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Lipidomics

Lipidomics is the large-scale study of pathways and networks of cellular lipids in biological systems. The word "lipidome" is used to describe the complete lipid profile within a cell, tissue, organism, or ecosystem and is a subset of the "metabolome" which also includes other major classes of biological molecules (such as amino acids, sugars, glycolysis & TCA intermediates, and nucleic acids). Lipidomics is a relatively recent research field that has been driven by rapid advances in technologies such as mass spectrometry (MS), nuclear magnetic resonance (NMR) spectroscopy, fluorescence spectroscopy, dual polarisation interferometry and computational methods, coupled with the recognition of the role of lipids in many metabolic diseases such as obesity, atherosclerosis, stroke, hypertension and diabetes. This rapidly expanding field complements the huge progress made in genomics and proteomics, all of which constitute the family of systems biology.

Lipidomics research involves the identification and quantification of the thousands of cellular lipid molecular species and their interactions with other lipids, proteins, and other metabolites. Investigators in lipidomics examine the structures, functions, interactions, and dynamics of cellular lipids and the changes that occur during perturbation of the system.

Han and Gross first defined the field of lipidomics through integrating the specific chemical properties inherent in lipid molecular species with a comprehensive mass spectrometric approach. Although lipidomics is under the umbrella of the more general field of "metabolomics", lipidomics is itself a distinct discipline due to the uniqueness and functional specificity of lipids relative to other metabolites.

In lipidomic research, a vast amount of information quantitatively describing the spatial and temporal alterations in the content and composition of different lipid molecular species is accrued after perturbation of a cell through changes in its physiological or pathological state. Information obtained from these studies facilitates mechanistic insights into changes in cellular function. Therefore, lipidomic studies play an essential role in defining the biochemical mechanisms of lipid-related disease processes through identifying alterations in cellular lipid metabolism, trafficking and homeostasis. The growing attention on lipid research is also seen from the initiatives underway of the LIPID Metabolites And Pathways Strategy (LIPID MAPS Consortium). and The European Lipidomics Initiative (ELIfe).

Structural diversity of lipids
Lipids are a diverse and ubiquitous group of compounds which have many key biological functions, such as acting as structural components of cell membranes, serving as energy storage sources and participating in signaling pathways. Lipids may be broadly defined as hydrophobic or amphipathic small molecules that originate entirely or in part from two distinct types of biochemical subunits or "building blocks": ketoacyl and isoprene groups. The huge structural diversity found in lipids arises from the biosynthesis of various combinations of these building blocks. For example, glycerophospholipids are composed of a glycerol backbone linked to one of approximately 10 possible headgroups and also to 2 fatty acyl/alkyl chains, which in turn may have 30 or more different molecular structures. In practice, not all possible permutations are detected experimentally, due to chain preferences depending on the cell type and also to detection limits - nevertheless several hundred distinct glycerophospholipid molecular species have been detected in mammalian cells.

Plant chloroplast thylakoid membranes however, have unique lipid composition as they are deficient in phospholipids. Also, their largest constituent, monogalactosyl diglyceride or MGDG, does not form aqueous bilayers. Nevertheless, dynamic studies reveal a normal lipid bilayer organisation in thylakoid membranes.

Lipid extraction
Most methods of lipid extraction and isolation from biological samples exploit the high solubility of hydrocarbon chains in organic solvents. Given the diversity in lipid classes, it is not possible to accommodate all classes with a common extraction method. The traditional Bligh/Dyer procedure uses chloroform/methanol-based protocols that include phase partitioning into the organic layer. However, several protocols now exist, with newer methods overcoming the shortcomings of older ones and solving problems associated with, for example, targeted lipid isolation or high throughput data collection . Most protocols work relatively well for a variety of physiologically relevant lipids but they have to be adapted for species with particular properties and low-abundance and labile lipid metabolites .

Lipid separation
The simplest method of lipid separation is the use of thin layer chromatography (TLC). Although not as sensitive as other methods of lipid detection, it offers a rapid and comprehensive screening tool prior to more sensitive and sophisticated techniques. Solid-phase extraction (SPE) chromatography is useful for rapid, preparative separation of crude lipid mixtures into different lipid classes. This involves the use of prepacked columns containing silica or other stationary phases to separate glycerophospholipids, fatty acids, cholesteryl esters, glycerolipids, and sterols from crude lipid mixtures. High-performance liquid chromatography (HPLC or LC) is extensively used in lipidomic analysis to separate lipids prior to mass analysis. Separation can be achieved by either normal-phase (NP) HPLC or reverse-phase (RP) HPLC. For example, NP-HPLC effectively separates glycerophospholipids on the basis of headgroup polarity, whereas RP-HPLC effectively separates fatty acids such as eicosanoids on the basis of chain length, degree of unsaturation and substitution. For global, untargeted lipidomic studies it is common to use both RP and NP or Hydrophilic Interaction Liquid Chromatrography (HILC) columns for increased lipidome coverage. The application of nano-flow liquid chromatography (nLC) proved thereby to be most efficient to enhance both general measurement sensitivity and lipidome coverage for a global lipidomics approach. Chromatographic (HPLC/UHPLC) separation of lipids may either be performed offline or online where the eluate is integrated with the ionization source of a mass spectrometer.

Lipid detection
The progress of modern lipidomics has been greatly accelerated by the development of spectrometric methods in general and soft ionization techniques for mass spectrometry such as electrospray ionization (ESI), desorption electrospray ionization (DESI), and matrix-assisted laser desorption/ionization (MALDI) in particular. "Soft" ionization does not cause extensive fragmentation, so that comprehensive detection of an entire range of lipids within a complex mixture can be correlated to experimental conditions or disease state. In addition, the technique of atmospheric pressure chemical ionization (APCI) has become increasingly popular for the analysis of nonpolar lipids.

ESI MS
ESI-MS was initially developed by Fenn and colleagues for analysis of biomolecules. It depends on the formation of gaseous ions from polar, thermally labile and mostly non-volatile molecules and thus is completely suitable for a variety of lipids. It is a soft-ionization method that rarely disrupts the chemical nature of the analyte prior to mass analysis. Various ESI-MS methods have been developed for analysis of different classes, subclasses, and individual lipid species from biological extracts. Comprehensive reviews of the methods and their application have recently been published. The major advantages of ESI-MS are high accuracy, sensitivity, reproducibility, and the applicability of the technique to complex solutions without prior derivatization. Han and coworkers have developed a method known as"shotgun lipidomics" which involves direct infusion of a crude lipid extract into an ESI source optimized for intrasource separation of lipids based on their intrinsic electrical properties.

DESI MS
DESI mass spectrometry is an ambient ionization technique developed by Professor Zoltan Takáts, et al., in Professor Graham Cooks' group from Purdue University. It combines the ESI and desorption ionization techniques, by directing an electrically charged mist to the sample surface that is a few millimeters away. The technique has been successfully applied to lipidomics as imaging tool to map the lipid distributions within tissue specimens. One of the advantages of DESI MS is that no matrix is required for tissue preparation, allowing multiple consecutive measurements on the same tissue specimen. DESI MS can also be used for imaging of lipids from tissue sections.

MALDI MS
MALDI mass spectrometry is a laser-based soft-ionization method often used for analysis of large proteins, but has been used successfully for lipids. The lipid is mixed with a matrix, such as 2,5-dihydroxybenzoic acid, and applied to a sample holder as a small spot. A laser is fired at the spot, and the matrix absorbs the energy, which is then transferred to the analyte, resulting in ionization of the molecule. MALDI-Time-of-flight (MALDI-TOF) MS has become a very promising approach for lipidomics studies, particularly for the imaging of lipids from tissue slides.

APCI MS
The source for APCI is similar to ESI except that ions are formed by the interaction of the heated analyte solvent with a corona discharge needle set at a high electrical potential. Primary ions are formed immediately surrounding the needle, and these interact with the solvent to form secondary ions that ultimately ionize the sample. APCI is particularly useful for the analysis of nonpolar lipids such as triacylglycerols, sterols, and fatty acid esters.

Imaging techniques
The high sensitivity of DESI in the lipid range makes it a powerful technique for the detection and mapping of lipids abundances within tissue specimens. Recent developments in MALDI methods have enabled direct detection of lipids in-situ. Abundant lipid-related ions are produced from the direct analysis of thin tissue slices when sequential spectra are acquired across a tissue surface that has been coated with a MALDI matrix. Collisional activation of the molecular ions can be used to determine the lipid family and often structurally define the molecular species. These techniques enable detection of phospholipids, sphingolipids and glycerolipids in tissues such as heart, kidney and brain. Furthermore, distribution of many different lipid molecular species often define anatomical regions within these tissues.

Lipid profiling
Lipid profiling is a targeted metabolomics platform that provides a comprehensive analysis of lipid species within a cell or tissue. Profiling based on electrospray ionization tandem mass spectrometry (ESI-MS/MS) is capable of providing quantitative data and is adaptable to high throughput analyses. The powerful approach of transgenics, namely deletion and/or overexpression of a gene product coupled with lipidomics, can give valuable insights into the role of biochemical pathways. Lipid profiling techniques have also been applied to plants and microorganisms such as yeast. A combination of quantitative lipidomic data in conjunction with the corresponding transcriptional data (using gene-array methods) and proteomic data (using tandem MS) enables a systems biology approach to a more in-depth understanding of the metabolic or signaling pathways of interest.

Informatics
A major challenge for lipidomics, in particular for MS-based approaches, lies in the computational and bioinformatic demands of handling the large amount of data that arise at various stages along the chain of information acquisition and processing. Chromatographic and MS data collection requires substantial efforts in spectral alignment and statistical evaluation of fluctuations in signal intensities. Such variations have a multitude of origins, including biological variations, sample handling and analytical accuracy. As a consequence several replicates are normally required for reliable determination of lipid levels in complex mixtures. Within the last few years, a number of software packages have been developed by various companies and research groups to analyze data generated by MS profiling of metabolites, including lipids. The data processing for differential profiling usually proceed through several stages, including input file manipulation, spectral filtering, peak detection, chromatographic alignment, normalization, visualization, and data export. An example of metabolic profiling software is the freely-available Java-based Mzmine application. Another is Metabolon, Inc’s commercial applications for metabolomic analysis using proprietary software. Recently MS-DIAL 4 software was integrated with a comprehensive lipidome atlas with retention time, collision cross-section and tandem mass spectrometry information for 117 lipid subclasses and 8,051 lipids. Some software packages such as Markerview include multivariate statistical analysis (for example, principal component analysis) and these will be helpful for the identification of correlations in lipid metabolites that are associated with a physiological phenotype, in particular for the development of lipid-based biomarkers. Another objective of the information technology side of lipidomics involves the construction of metabolic maps from data on lipid structures and lipid-related protein and genes. Some of these lipid pathways are extremely complex, for example the mammalian glycosphingolipid pathway. The establishment of searchable and interactive databases of lipids and lipid-related genes/proteins is also an extremely important resource as a reference for the lipidomics community. Integration of these databases with MS and other experimental data, as well as with metabolic networks offers an opportunity to devise therapeutic strategies to prevent or reverse these pathological states involving dysfunction of lipid-related processes.

title: Lipidomics


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UNIVAC 1100/60

The UNIVAC 1100/60, introduced in 1979, continued the venerable UNIVAC 1100 series first introduced in 1962 with the UNIVAC 1107. The 1107 was the first 1100-series machine introduced under the Sperry Corporation name.

Like its predecessors, it had support for multiple CPUs; initially only two, but later up to four. It continued the naming convention introduced with the 1100/10, where the last digit represented the number of CPUs (thus, a four CPU system would be an 1100/64).

The 1100/60 introduced a new feature to the line: the CPUs used microcode that was loaded during the booting process. The booting process was controlled by a microcomputer (called the "SSP" - "System Support Processor") that ran from 8-inch floppy disks. The microcode was stored on these disks.

The system included an optional (extra-cost) set of additions to the instruction set (referred to as the Extended Instruction Set or EIS), which contained features to enhance the execution of COBOL programs, when appropriately compiled.

The UNIVAC 1100/70 shared much of the same architecture, including the same console and microcode.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: UNIVAC 1100/60


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Pikaia

Pikaia gracilens is an extinct, primitive chordate animal known from the Middle Cambrian Burgess Shale of British Columbia. Described in 1911 by Charles Doolittle Walcott as an annelid, and in 1979 by Harry B. Whittington and Simon Conway Morris as a chordate, it became "the most famous early chordate fossil", or "famously known as the earliest described Cambrian chordate". It is estimated to have lived during the latter period of the Cambrian explosion. Since its initial discovery, more than a hundred specimens have been recovered.

The body structure resembles that of the lancelet and it swam perhaps much like an eel. A notochord and myomeres (segmented blocks of skeletal muscles) span the entire length of the body, and are considered the defining signatures of chordate characters. Its primitive nature is indicated by the body covering, a cuticle, which is characteristic of invertebrates and some protochordates. A reinterpretation in 2024 found evidence of the gut canal, dorsal nerve cord and myomeres, and suggested that the taxon was previously interpreted upside down.

The exact phylogenetic position is unclear, though recent studies suggest that it is likely a stem-chordate with crown group traits. Previously proposed affinities include those of cephalochordata, craniata, or a stem-chordate not closely related to any extant lineage. Popularly but falsely attributed as an ancestor of all vertebrates, or the oldest fish, or the oldest ancestor of humans, it is generally viewed as a basal chordate alongside other Cambrian chordates; it is a close relative of vertebrate ancestors  but it is not an ancestor itself.

Discovery
The fossils of Pikaia gracilens was discovered by Charles Walcott from the Burgess shale member of the Stephen formation in British Columbia, and described it in 1911. He named it after Pika Peak, a mountain in Alberta, Canada. Based on the obvious and regular segmentation of the body, as is the feature of annelids, Walcott classified it as a polychaete worm and created a new family Pikaidae for it. (Princeton palaeontologist Benjamin Franklin Howell changed the name of the family to Pikaiidae in 1962. ) Walcott was aware of the limitation of his classification, as he noted: "I am unable to place it within any of the families of the Polychaeta, owing to the absence of parapodia [paired protrusions on the sides of polychaete worms] on the body segments back of the fifth."

University of Cambridge palaeontologist Harry B. Whittington and his student Simon Conway Morris re-examined the Burgess Shale fauna and noted the anatomical details of Pikaia for the first time. The fossil specimens bears features of notochord and muscle blocks that are fundamental structures of chordates, and not of annelids. In 1977, Conway Morris presented a paper that indicated the possible chordate position, without further explanation. He and Whittington were convinced that the animal was obviously a chordate, as they wrote in Scientific American in 1979:"Finally, we find among the Burgess Shale fauna one of the earliest-known invertebrate representatives of our own conspicuous corner of the animal kingdom: the chordate phylum... The chordates are represented in the Burgess Shale by the genus Pikaia and the single species P. gracilens."Conway Morris formally placed P. gracilens among the chordates in a paper in the Annual Review of Ecology and Systematics that same year. However, he provided no structural analyses such as using microscopes to confirm the chordate features. The comparative description only earned a "putative" chordate status. The fossil's chordate nature was received sceptically for several decades. Only in 2012, when detailed analysis was reported by Conway Morris and Jean-Bernard Caron, that the chordate position became generally accepted.

The fossils are found only in a restricted series of horizons in the strata exposed on Fossil Ridge, close to the Yoho National Park. From the same location, other fish-like animal fossils named Metaspriggina were discovered in 1993. Conway Morris identified the animals as another Cambrian chordate. The fossil specimens are preserved in the Smithsonian Institution and the Royal Ontario Museum.

Description
Pikaia has a lancelet-like body, tapering at both ends, laterally flat and lacked a well-defined head. It measures an average of about 1+1/2 in in length. Walcott recorded the longest individuals as 5 cm in length. Pikaia has a pair of large, antenna-like tentacles on its head that resembles those of invertebrates such as snails. The attachment of the tentacles makes a two-lobed structure of the head. The tentacles may be comparable to those in the present-day hagfish, a jawless chordate. It has a small circular mouth that could be used to eat small food particles in a single bite. There are a series of short appendages on either side of the underside of the head just after the mouth, and their exact nature or function is unknown. The pharynx is associated with six pairs of slits with tiny filaments that could be used for respiratory apparatus. In these ways, it differs from the modern lancelets, which have distinct pharyngeal gill slits on either sides of the pharynx and are used for filter feeding.

A major primitive structure of Pikaia is a cuticle as its body covering. Cuticle is a hard protein layer predominantly found in invertebrates such as arthropods, molluscs, echinoderms and nematodes. Unlike a typical cuticle, the cuticle of Pikaia does not have hard extracellular (exoskeleton) protection, and the entirely body is essentially soft-bodied. Although primitive, Pikaia shows the essential prerequisites for vertebrates. When alive, Pikaia was a compressed, leaf-shaped animal with an expanded tail fin; the flattened body is divided into pairs of segmented muscle blocks, seen as faint vertical lines. The muscles lie on either side of a flexible structure resembling a rod that runs from the tip of the head to the tip of the tail.

Pikaia was an active and free swimmer. It likely swam by throwing its body into a series of S-shaped, zigzag curves, similar to the movement of eels; fish inherited the same swimming movement, but they generally have stiffer backbones. These adaptations may have allowed Pikaia to filter particles from the water as it swam along. Pikaia was probably a slow swimmer, since it lacked the fast-twitch fibers that are associated with rapid swimming in modern chordates.

Reinterpretations
Walcott's original summary of the description of Pikaia reads:"Body elongate, slender, and tapering at each end. It is formed of many segments that are defined by strong annular shiny lines. Head small with two large eyes and two tentacles... Back of the head the first five segments carry short parapodia that appear to be divided into two parts. The enteric canal extends from end to end without change in character... This was one of the active, free-swimming annelids that suggest the Nephthydidae of the Polychaeta."Whittington and Conway Morris were the first to realise that Walcott's description and classification were not reliable and mostly inaccurate. They compared the body segments as described by Walcott with living animals and found that they were similar to the muscle bundles of chordates such as the living Amphioxus (Branchiostoma) as well as fishes, and not to superficial segments of annelids. They pictured that the muscles would be essential for swimming in water in wriggling motions. The enteric canal as observed by Walcott was not an ordinary digestive tract, it runs along with a stiff rod that resembles a notochord. They reported in 1979: "Although Pikaia differs from Amphioxus, in several important respects, the conclusion is that it is not a worm but a chordate appears inescapable."

Conway Morris was convinced that the longitudinal rod was a notochord and the segments were muscle blocks that he concluded that Pikaia "is a primitive chordate rather than a polychaete. The earliest fish scales are Upper Cambrian, and Pikaia may not be far removed from the ancestral fish." In 1982, he added further description in his Atlas of the Burgess Shale that Pikaia had one or more fins, but did not specify where they were present.

Pikaia was not popularly known as a chordate fossil or as an ancient chordate until 1989. That year, Harvard University palaeontologist Stephen Jay Gould wrote in his book Wonderful Life: The Burgess Shale and the Nature of History: "Pikaia is not an annelid worm. It is a chordate, a member of our own phylum—in fact, the first recorded member of our immediate ancestry." From this remark Pikaia became generally recognised as a chordate and ancestor of vertebrates.

In 1993, Conway Morris came up with another possible chordate feature. He identified structures that looked like gill slits but gave a cautious remark: "[They] may have been present, but are hard to identify with certainty in the compressed material available. The tiny pores on the side of the pharynx are normally gill slits in living chordates. He also noticed that Pikaia is similar to Amphioxus in most general aspects, with major difference in its notochord not reaching the anterior end.

Not all palaeontologists were convinced of the chordate designation without better analysis. In 2001, Nicholas D. Holland from the Scripps Institution of Oceanography and Junyuan Chen from the Chinese Academy of Sciences criticised the presentation in Wonderful Life, saying that the "reinterpretation [of Pikaia as a chordate] became almost universally accepted after its unqualified and forceful endorsement by Gould"; concluding that "the cephalochordate affinity of Pikaia is at best only weakly indicated by the characters visible in fossils discovered so far." In 2010, an international team of palaeontologists argued that Pikaia has sufficiently invertebrate characters, and that it mostly look like a much younger extinct animal, the Tully monster (Tullimonstrum gregarium), which is still debated as either an invertebrate or a chordate.

Another component of Pikaia fossils that constrains the animal to be accepted as a chordate is its distinct invertebrate character; its preservational mode suggests that it had cuticle. The cuticle as a body covering is uncharacteristic of the vertebrates, but is a dominant feature of invertebrates. The presence of earlier chordates among the Chengjiang, including Haikouichthys and Myllokunmingia, appears to show that cuticle is not necessary for preservation, overruling the taphonomic argument, but the presence of tentacles remains intriguing, and the organism cannot be assigned conclusively, even to the vertebrate stem group. Its anatomy closely resembles the modern creature Branchiostoma.

A fossil species Myoscolex ateles, discovered in 1979 from Cambrian Emu Bay shale of Kangaroo Island in South Australia, had been debated as among the oldest annelids, or at least other invertebrate groups. Polish palaeontologist Jerzy Dzik in his formal description in 2003 notes that it "closely resembles the slightly geologically younger Pikaia" in having smooth cuticle as well as muscular segmentation, and projections on its backside (ventral chaetae) that look like Pikaia 's tentacles. He concluded:"In fact, there is little evidence for chordate affinities of Pikaia. Its relationship with Myoscolex [as annelid in his proposition] appears a much better solution. Both were initially identified as polychaetes and this line of inference perhaps deserves confrontation with more recent evidence than that available to the authors who proposed these genera."

Comprehensive description
The first comprehensive description of Pikaia was published by Conway Morris and Jean-Bernard Caron in the May 2012 issue of Biological Reviews. The anatomical examination and interpretation based on 114 fossil specimens confirm the classification as a chordate. According to the new assessment, Pikaia fossils indicate important features that define the animal as a primitive chordate. All Pikaia fossils are in the range of 1.5 to 6 cm in length, with an average of 4 cm. Having a laterally compressed (taller than wide) and fusiform (tapering at both ends) body, the exact width and height are variable, and normally its height is twice that of its width throughout it body.

The head is bilaterally symmetrical with a distinct pair of tentacles. Due to its small size, only about 1 mm in diameter, the structural details are indistinguishable. Some specimens show a darker central line on the tentacles which may represent a nervous fibre; thus making the tentacles as sensory feelers. A mouth is marked by a small opening at the anterior end of the gut towards the underside of the head. There are no jaws and teeth. Walcott had mentioned the presence of two large eyes, but no specimens, including Walcott's original collection, show any evidence of eyes.

One of the most unusual body parts is a series of appendages just posterior to the tentacles. Walcott had called the appendages parapodia, as a kind of body protrusions that aid locomotion in snails, and mentioned five parapodia in each individual. He was even puzzled by the absence on the major part of the body, with other specimens having up to nine such appendages that could not be parapodia. These external appendages were reinterpreted as gills in a 2024 study. Fins are present as an expansion of the body on the dorsal and ventral sides. They are not present in many specimens indicating that they are delicate membranes and were lost during fossilisation. However, the 2024 study suggested that Pikaia was previously interpreted upside down, indicating that the 'dorsal and ventral' sides of Pikiaia were actually inverted.

The backside of Pikaia fossils show a hollow tubular structure that extends throughout most of the body length, but not the anterior region. It is easily noticeable as a highly light-reflective portion and is known as the dorsal organ. Once described as the notochord, its nature is not yet fully resolved and could be a storage organ. The true notochord, along with a nerve cord, is a fine lateral line that runs just beneath the thick dorsal organ. A 2024 study instead found evidence of the gut canal, dorsal nerve cord and myomeres from the specimens, providing more evidence with diagnostic features that Pikaia is a chordate.

The main chordate character is a series of myomeres that extends from the anterior to the posterior region. On average, there are 100 such myomeres in each individual. The muscle segments are not simply "annular shiny lines" as Walcott described, but are in concentric bends in the form of V-shaped chevron. The myomeres at the anterior end as simpler in appearance and show circular arrangement. Conway Morris and Caron concluded:"Whilst the possibility that Pikaia is simply convergent on the chordates cannot be dismissed, we prefer to build a scenario that regards Pikaia as the most stem-ward of the chordates with links to the phylogenetically controversial yunnanozoans. This hypothesis has implications for the evolution of the myomeres, notochord and gills."

Evolutionary importance
Much debate on whether Pikaia is a vertebrate ancestor, its worm-like appearance notwithstanding, exists in scientific circles. It looks like a worm that has been flattened sideways (lateral compression). The fossils compressed within the Burgess Shale show chordate features such as traces of an elongate notochord, dorsal nerve cord, and blocks of muscles (myotomes) down either side of the body – all critical features for the evolution of the vertebrates.

The notochord, a flexible rod-like structure that runs along the back of the animal, lengthens and stiffens the body so that it can be flexed from side to side by the muscle blocks for swimming. In the fish and all subsequent vertebrates, the notochord forms the backbone (or vertebral column). The backbone strengthens the body, supports strut-like limbs, and protects the vital dorsal nerve cord, while at the same time allowing the body to bend.

A Pikaia lookalike, the lancelet Branchiostoma, still exists today. With a notochord and paired muscle blocks, the lancelet and Pikaia belong to the chordate group of animals from which the vertebrates descended. Molecular studies have refuted earlier hypotheses that lancelets might be the closest living relative to the vertebrates, instead favoring tunicates in this position; other extant and fossil groups, such as acorn worms and graptolites, are more primitive.

The presence of cuticle, one of the principal characters of higher invertebrates, in Pikaia can be understood from the evolutionary trends. A Cambrian invertebrate, Myoscolex ateles was described to be structurally similar to Pikaia particularly in having smooth cuticle as well as muscular segmentation, and projections on its backside (ventral chaetae) that look like Pikaia 's tentacles. Although chordates normally lack the cuticle, a type of cuticle is present in some cephalochordates, indicating that primitive characters are retained in lower chordates.

Subsequently, Mallatt and Holland reconsidered Conway Morris and Caron's description, and concluded that many of the newly recognized characters are unique, already-divergent specializations that would not be helpful for establishing Pikaia as a basal chordate.

Development of the head
The first sign of head development, cephalization, is seen in chordates such as Pikaia and Branchiostoma. It is thought that development of a head structure resulted from a long body shape, a swimming habit, and a mouth at the end that came into contact with the environment first, as the animal swam forward. The search for food required ways of continually testing what lay ahead so it is thought that anatomical structures for seeing, feeling, and smelling developed around the mouth. The information these structures gathered was processed by a swelling of the nerve cord (efflorescence) – the precursor of the brain. Altogether, these front-end structures formed the distinct part of the vertebrate body known as the head.

Evolutionary interpretation
Once thought to be closely related to the ancestor of all vertebrates, Pikaia has received particular attention among the multitude of animal fossils found in the famous Burgess Shale and other Cambrian fauna. In 1979, Whittington and Conway Morris first explained the evolutionary importance of Pikaia. Realising the fossil to be that of a chordate in the Cambrian rocks, chordates could have originated much earlier than expected, as they commented: "The superb preservation of this Middle Cambrian organism [Pikaia] makes it a landmark history of the phylum [Chordata] to which all vertebrates, including man, belong." It is for this knowledge Pikaia as an old chordate that it is often misleadingly and falsely attributed to as an ancestor of all vertebrates, or the oldest fish, or the oldest ancestor of humans.

Before Pikaia and other Cambrian chordates were fully appreciated, it was generally believed that the first chordates appeared much later, such as in Ordovician (484–443 mya). The establishment of Cambrian chordates, according to Stephen Jay Gould, prompted "revised views of evolution, ecology and development," and remarked: "So much for chordate uniqueness marked by slightly later evolution." However, Gould did not believe that Pikaia itself was unique as an early chordate or that it was "the actual ancestor of vertebrates;" he presumed that there could be undiscovered fossils that are more closely linked to vertebrate ancestry.

Gould's interpretation and evolutionary contingency
Gould, in his presidential address of the Paleontological Society on 27 October 1988, cited Pikaia to explain the trends of evolutionary changes: Wind back life's tape to the Burgess (first erasing what actually came after), let it play again, and this time a quite different cast may emerge. If the cast lacked Pikaia, the first chordate, we might not be here—and the world would be no worse... Let us thank our lucky stars for the survival of Pikaia. He elaborated the same idea in "An epilogue on Pikaia" in his book Wonderful Life "to save the best for the last," in which he made a statement: Pikaia is the missing and final link in our story of contingency—the direct connection between Burgess decimation and eventual human evolution... Wind the tape of life back to Burgess times, and let it play again. If Pikaia does not survive in the replay, we are wiped out of future history—all of us, from shark to robin to orangutan...

And so, if you wish to ask the question of the age—why do humans exist?—a major part of the answer, touching those aspects of the issue that science can treat at all, must be: because Pikaia survived the Burgess decimation. This interpretation that the chances of evolutionary products are unpredictable is known as evolutionary contingency. Gould, from this statement, is regarded as "the most famous proponent" of the concept. His idea has inspired many research involving evolutionary contingency from palaeontology to molecular biology. He used Pikaia among the Cambrian animals as an epitome of contingent event in the entire evolution of life; if Pikaia had not existed, the rest of chordate animals might not have evolved, thus completely changing the diversity of life as we know. According to him, contingency is a major factor that drives large-scale evolution (macroevolution) and dictates that evolution has no inevitable destiny or outcome. However, as Gould explained, "The bad news is that we can't possibly perform the experiment."

Ecology
Pikaia is suggested to have been an active swimming organism that swam close to the seafloor (nektobenthic) using side to side undulations of its flattened posterior for propulsion. The anterior appendages are unlikely to have been used in feeding, and may have had a respiratory function. Pikaia is suggested to have fed on small particles of organic matter.

title: Pikaia


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Ranger 6

Ranger 6 was a lunar probe in the NASA Ranger program, a series of robotic spacecraft of the early and mid-1960s to obtain close-up images of the Moon's surface. It was launched on January 30, 1964 and was designed to transmit high-resolution photographs of the lunar terrain during the final minutes of flight until impacting the surface. The spacecraft carried six television vidicon cameras—two wide-angle (channel F, cameras A and B) and four narrow-angle (channel P)—to accomplish these objectives. The cameras were arranged in two separate chains, or channels, each self-contained with separate power supplies, timers, and transmitters so as to afford the greatest reliability and probability of obtaining high-quality television pictures. No other experiments were carried on the spacecraft. Due to a failure of the camera system, no images were returned.

Spacecraft design
Rangers 6, 7, 8, and 9 were called Block 3 versions of the Ranger spacecraft. The spacecraft consisted of a hexagonal aluminum frame base 1.5m across on which was mounted the propulsion and power units, topped by a truncated conical tower that held the TV cameras. Two solar panel wings, each 739mm wide by 1537mm long, extended from opposite edges of the base with a full span of 4.6m, and a pointable high-gain dish antenna was hinge mounted at one of the corners of the base away from the solar panels. A cylindrical quasi omnidirectional antenna was seated on top of the conical tower. The overall height of the spacecraft was 3.6m.

Propulsion for the mid-course trajectory correction was provided by a 224N thrust monopropellant hydrazine engine with four jet-vane vector control. Orientation and attitude control about three axes were enabled by twelve nitrogen gas jets coupled to a system of three gyros, four primary Sun sensors, two secondary Sun sensors, and an Earth sensor. Power was supplied by 9,792 silicon solar cells contained in the two solar panels, giving a total array area of 2.3 square meters and producing 200W. Two 1200 watt-hour AgZnO batteries rated at 26.5V with a capacity for 9 hours of operation provided power to each of the separate communication/TV camera chains. Two 1000 watt-hour AgZnO batteries stored power for spacecraft operations.

Communications were through the quasi omnidirectional low-gain antenna and the parabolic high-gain antenna. Transmitters aboard the spacecraft included a 60W TV channel F at 959.52MHz, a 60W TV channel P at 960.05MHz, and a 3W transponder channel 8 at 960.58MHz. The telecommunications equipment converted the composite video signal from the camera transmitters into an RF signal for subsequent transmission through the spacecraft high-gain antenna. Sufficient video bandwidth was provided to allow for rapid framing sequences of both narrow- and wide-angle television pictures.

Mission profile
The Cuban Missile Crisis had momentarily diverted attention from the failure of Ranger 5, but that mission forced a wholesale review of the entire Ranger program. Numerous theories were put forward about the cause of the failures, including poor management at JPL, overly-ambitious spacecraft designs that were unworkable and unreliable with contemporary technology, and some lesser reasons such as heat sterilization of the probes.

NASA established a Ranger Board of Inquiry on October 29, 1962, headed by Albert J. Kelley, with the mission of establishing by November 30 the reasons for the continued program failures. The board's findings included the verdict that the Ranger design was "more complicated than necessary" for a lunar mission and also required a very high degree of engineering and workmanship, neither of which were being delivered. They also concluded that heat sterilization was damaging to the delicate spacecraft systems and should be abandoned at once. They also found that JPL's handling of the program was poor, the spacecraft lacked redundant systems in the event of a malfunction, NASA's deep-space tracking network crews were not trained adequately and had deficiencies in their equipment, and finally, the Atlas-Agena booster's reliability was poor, having malfunctioned on eight Air Force and NASA launches as November 1962 ended. If the Thor-Agena was also counted in, there had been a total of nine times that an Agena B stage had malfunctioned in flight.

The board's recommendations included improving the management of projects, abandoning heat sterilization and testing of components designed for future planetary missions on Ranger, outsourcing assembly of the probes to a subcontractor, and excluding JPL from involvement in procurement and launching of the Atlas-Agena. Moreover, it suggested that NASA needed to improve their prelaunch testing and preparation of launch vehicles.

The Block III spacecraft would be stripped down to a minimum of instrumentation with the eight scientific instruments on Rangers 3-5 removed so that more space could be devoted to redundant systems hardware. This caused some protests from the scientific community that the gamma-ray and other measurements were far more valuable than simply returning photography of the Moon. Jet Propulsion Laboratory began more thorough testing of Ranger components and the second review board was put to work evaluating the reliability of the Atlas-Agena.

The booster problems would prove a particularly vexing one to solve because the U.S. Air Force, not NASA, was in charge of Atlas-Agena. Although NASA had hoped to launch planetary probes on Centaur, which was entirely under their control, that program was delayed by serious technical issues and would not be flight-ready for a long time. Having to share the booster with the U.S. Air Force and its Department of Defense missions on the West Coast created repeated mixups, delays, and technical problems. Therefore, it was recommended that NASA be given complete oversight in the procurement and launch of Atlas-Agena without the Air Force's involvement.

One of the important parts of the Ranger program was monitoring all Atlas and Thor-Agena launches to check for failures that could directly affect it. This job had been assigned to the Marshall Space Flight Center in Huntsville, Alabama, but was instead moved to the Lewis Research Center (LRC) in Cleveland, Ohio. LRC sent additional personnel to the Convair assembly plant in San Diego to monitor the construction of Atlas vehicles.

The review board focused on the malfunctions plaguing Atlas-Agena, in particular, the General Electric guidance system, both the Mod III-G variant used on East Coast Atlas Agenas and the Mod II-A used on West Coast vehicles, which had malfunctioned repeatedly. They recommended putting forward more detailed and stringent requirements for testing Atlas vehicles and making sure the guidance package could withstand in-flight vibration levels along with improved fabrication of wiring harnesses. Also, it was recommended that Convair establish one standardized booster configuration for all U.S. Air Force and NASA launches instead of custom modifications for each mission, replacing hardware with known design flaws with better substitutes, and improved testing of everything. Since the Air Force was in charge of Atlas-Agena, it followed that all these changes required their approval.

Finally, NASA for the first time would be given complete oversight of all its space launches. Air Force involvement in procuring, preparing, and flying launch vehicles, as well as drafting postflight mission reports for NASA missions, was to end, a step that would greatly streamline and improve program efficiency.

Problems continued, this time with getting the TV cameras for Ranger 6 in working order. The camera tubes, supplied by Radio Corporation of America, were of variable quality and it took some time to find one that matched JPL's standards.

During testing of Atlas guidance systems at General Electric, it was found that gold coating on diodes was flaking off and causing electrical shorts. Even worse, Ranger 6 had hundreds of the same diodes. This problem had easily eluded testing; moreover, ground tests could not simulate a "zero gravity" environment in space where the gold flakes would float around and form a short between the legs of the diode. In the end, there was no choice except to replace every one of the several hundred diodes inside Ranger 6's circuitry.

In April 1963, the United States Congress also decided to cut funding to the Ranger program by nearly 50% on the grounds that "no success had been achieved with any of the missions to date". This meant that plans for Ranger probes up to 13 were cancelled. Only Rangers 6-9 would be flown and they would carry little more than a TV camera.

One of the Ranger program's goals was looking for potential landing sites for crewed lunar missions. At this point, it was not clear exactly what the Moon's surface was like and widespread fears existed of there being bottomless quicksand that would swallow up spacecraft and astronauts. Since the basic design of the Apollo lunar module had already been finalized by 1963, landing on the Moon would only "confirm or deny that design". JPL decided to go for an impact point near the lunar equator, in the Sea of Tranquility, partially because it was considered a prime Apollo landing spot, and also because the target had to match lighting conditions during the time of launch in January–February.

Ranger 6 and its launch vehicle (Atlas 199D and Agena 6008) arrived at Cape Canaveral in mid-December and, with the nation still mourning President Kennedy's assassination the previous month, began preflight tests.

Liftoff took place at 10:49 AM EST on January 30, 1964. The Atlas lifted smoothly into an overcast sky and disappeared from view. All went well during the boost phase and the launch vehicle's performance was excellent, indicating the hard-fought effort to improve booster reliability.

Shortly after Atlas BECO and staging, an ominous development occurred when telemetry indicated that the telemetry for the TV camera on Ranger 6 had turned itself on and then back off again 67 seconds later. Telemetry data showed everything else appears to function normally and tensions at JPL eased. The Agena placed the probe into a parking orbit and then fired for translunar injection 25 minutes after launch. After separation of Ranger 6, the solar panels and high-gain antenna were extended and all appeared normal. The launch vehicle had placed the probe on an accurate enough flight path that only a short midcourse correction burn would be required. However, the activation of the TV camera telemetry during launch remained a cause for concern. JPL technicians wanted to turn the camera on to verify its operability, however, they were running the risk of not being able to turn it off again if an electrical short had indeed occurred somewhere. Since the camera had its own batteries and did not use the probe's main power bus, they would be depleted before it could get to the Moon and eliminate any chance of returning pictures. They decided that it was not worth compromising the mission and the camera would not be touched until descent to the Moon began.

Early on the morning of January 31, the command was sent to fire the midcourse correction engine, which performed flawlessly and set the probe on an impact course with the Sea of Tranquility. On February 2, JPL technicians prepared for the final phase of the mission. Ranger 6 began its descent and trajectory calculations determined that impact would occur close to the intended area. With the probe's angle suitable for taking images, the order was given to turn on the camera with 13 minutes and 10 seconds until impact. After an initial warm-up phase, the command to power them on was sent. However, no imagery or any sign of camera operation appeared. Two more commands were sent to turn on the camera, but still, nothing happened even though all other systems continued to operate normally. At 01:24 AM, impact with the Moon occurred and telemetry transmission from Ranger 6 ceased. The mission was over and for the 12th time in a row, a U.S. attempt to send a probe to the Moon had malfunctioned. Even worse, it had occurred one week before NASA officials were planning to announce to Congress their projected US$5.3 billion budget for FY 1965, a good deal of it related to crewed and uncrewed lunar missions. NASA attempted to put a positive spin on the mission by noting that, aside from the cameras, Ranger 6 and its Atlas-Agena booster had both functioned "extremely well".

Ranger 6 was launched into an Earth parking orbit and injected on a lunar trajectory by a second Agena burn. The midcourse trajectory correction was accomplished early in the flight by ground control. On February 2, 1964, 65.5 hours after launch, Ranger 6 impacted the Moon on the eastern edge of Mare Tranquillitatis (Sea of Tranquility in English). The orientation of the spacecraft to the surface during descent was correct, but no video signal was received and no camera data obtained. A review board determined the most likely cause of failure was due to an arc-over in the TV power system when it inadvertently turned on for 67 seconds approximately 2 minutes after launch during the period of booster-engine separation.

This fourth American attempt at lunar impact was the closest success. The spacecraft, the first Block III type vehicle with a suite of six TV cameras, was sterilized to avoid contaminating the lunar surface. The series would also serve as a test bed for future interplanetary spacecraft by deploying systems (such as solar panels) that could be used for more ambitious missions. The Block III spacecraft carried a 173-kilogram TV unit (replacing the impact capsule carried on the Block II Ranger spacecraft). The six cameras included two full-scan and four partial-scan cameras. Ranger 6 flew to the Moon successfully and impacted precisely on schedule at 09:24:32 GMT on February 2. Unfortunately, the power supply for the TV camera package had short-circuited three days previously during Atlas booster separation and left the system inoperable. The cameras were to have transmitted high-resolution photos of the lunar approach from 1448 kilometers to 6.4 kilometers range in support of Project Apollo. Impact coordinates were 9°24' north latitude and 21°30' east longitude.

title: Ranger 6


text:
U.S. Route 8

U.S. Highway 8 (US 8) is a United States Numbered Highway that runs primarily east–west for 280 mi, mostly within the state of Wisconsin. It connects Interstate 35 (I-35) in Forest Lake, Minnesota, to US 2 at Norway in the Upper Peninsula of Michigan near the border with Wisconsin. Except for the short freeway segment near Forest Lake, a section near the St. Croix River bridge, the interchange with US 51, and a 3 mi stretch west of Rhinelander, Wisconsin, it is mostly an undivided surface road. As a state highway in the three states, US 8 is maintained by the Minnesota, Wisconsin and Michigan departments of transportation (MnDOT, WisDOT, and MDOT, respectively).

The highway was originally commissioned on November 11, 1926, with the rest of the original U.S. Highway System. At the time, it ran between Forest Lake, Minnesota, and Pembine, Wisconsin, with a planned continuation to Powers, Michigan. Several changes have been made to the routing of the highway since then. The western end was extended south to Minneapolis before it was truncated back to Forest Lake. Other changes on the east end have moved that terminus from the originally planned end location at Powers to the current location in Norway. Internal WisDOT and MDOT map files at various times have shown plans to reroute the highway to connect to the original planned 1926 terminus. US 8's course through the three states has also been shifted to follow different alignments over the years.

WisDOT built a bypass around the city of Rhinelander in the 1990s and created a business loop along the old highway through the town. This loop was a locally maintained route through the central business district in Rhinelander. The signage for the loop was removed in 2005.

Forest Lake to St. Croix Falls
US 8 begins at an interchange with I-35 in Forest Lake. This interchange is incomplete: traffic can only access US 8 directly from northbound I-35, and westbound traffic on US 8 merges onto southbound I-35. The first 1 mi segment of roadway to Forest Lake is a freeway, with an interchange at US 61. East of this junction, the highway follows Lake Boulevard North around Forest Lake and continues northeasterly through the community to cross the Washington–Chisago county line. The highway continues to the northeast along farmland and the shore of Green Lake to Chisago City, where it meets up with County State-Aid Highway 22 (CSAH 22). US 8 follows Lake Boulevard through Chisago City along the isthmus between the larger Chisago Lake and the smaller Wallmark Lake on the eastern side of town. The highway turns along a more easterly path in Lindström between North and South Lindström lakes. East of those lakes, US 8 crosses into the town of Center City.

In Center City, US 8 runs between North and South Center lakes, curving around the north shore of South Center Lake. On the eastern edge of town, it turns due east for several miles and runs through Shafer. US 8 merges with Minnesota State Highway 95 (MN 95) at a roundabout about 2 mi southwest of Taylors Falls. The two highways concurrently turn northeast along the St. Croix River, entering town. At this point, MN 95 continues north along the river while US 8 turns east to cross the St. Croix River, exiting the state of Minnesota into Wisconsin.

Legally, the Minnesota section of US 8 is defined as Constitutional Route 46 and Legislative Route 98 in the Minnesota Statutes §§161.114(2) and 161.115(29); the roadway is not marked with those numbers. The section of US 8 in Chisago County was officially designated the Moberg Trail in 1990.

St. Croix Falls to Rhinelander
US 8 enters Polk County at St. Croix Falls as a multilane roadway. It joins State Trunk Highway 35 (WIS 35) at a diamond interchange located approximately 1 mi from the state line. The two highways run concurrently for 4 mi before WIS 35 turns off to the north at a location in the Town of St. Croix Falls west of Deer Lake. US 8 continues eastward through forest lands, and WIS 46 joins from the north for a 4 mi concurrency before splitting off to the south. Continuing eastward, US 8 passes through Range and crosses into Barron County at Turtle Lake. US 63 merges from the south near Turtle Lake and departs to the north in the downtown area. The roadway passes through Poskin and intersects WIS 25 in Barron. East of Barron, US 8 meets US 53 at a mixed diamond/cloverleaf interchange and turns north into Cameron, then turns east in downtown to leave the latter community. After a 9 mi straightaway, the highway crosses into Rusk County, and then it continues due east for an additional 5 mi before turning northeast and passing through Weyerhaeuser. Continuing northeasterly, the roadway crosses WIS 40 in Bruce. East of town, the highway continues through rural Rusk County, and US 8 meets WIS 27 in downtown Ladysmith.

Upon leaving Ladysmith, US 8 passes through the communities of Tony, Glen Flora, Ingram (where it meets the northern terminus of WIS 73) and Hawkins on its way out of Rusk County. In Price County, US 8 passes through Kennan and Catawba. WIS 111 terminates at its south end on US 8 just east of Catawba. US 8 meets WIS 13 at a diamond interchange northwest of Prentice and passes north of the city. The highway passes through Brantwood and enters Lincoln County at Clifford. Further east, US 8 crosses Tripoli and McCord and runs north of Tomahawk as it passes through the Lake Nokomis area. US 51 crosses US 8 northeast of Tomahawk. US 8 turns northeast into Oneida County and onto a forested twisting northeasterly alignment. For much of this segment the highway follows the Soo Line Railroad. The highway passes through Woodboro and passes several lakes. A few miles before Rhinelander, the highway expands to a divided highway into Rhinelander. During this stretch, the highway has an exempt railroad crossing with only crossbucks. It merges with WIS 47 at a roundabout on the southwest side of Rhinelander. WIS 17 north joins the highways 1/2 mi to the southeast, creating a wrong-way concurrency with WIS 47; along this section of highway, eastbound US 8 is also southbound WIS 47 and northbound WIS 17 and vice versa. WIS 17 turns to the north 2 mi southeast of there, and US 8 and WIS 47 head eastbound out of the Rhinelander area.

Rhinelander to Norway
US 8 intersects US 45 south in Monico, and WIS 47 splits from US 8 to follow US 45 south. Immediately east of the same intersection, US 45 north follows US 8 for 1 mi before splitting to the north. US 8 enters Forest County 5 mi east of Monico. 7 mi into the county, the highway merges with WIS 32 from the north in Crandon and the two highways head east to Laona where US 8 turns north and WIS 32 turns south. US 8 turns east again at Cavour and passes through the community of Armstrong Creek 1 mi from the Marinette County line. The highway passes through Goodman and Dunbar as it meanders through the county and joins US 141 at Pembine. The two routes split 10 mi further north near Niagara; after the split, US 8 heads east. The highway takes a northward turn and heads across the Menominee River into Michigan near Pier's Gorge Park.

Entering Michigan south of Norway at the Menominee River crossing in Norway Township, US 8 proceeds north into the city where it ends at US 2. US 8 in Michigan is 2.322 mi long; in this segment, the road passes by the Dickinson County fairgrounds and Norway Speedway.

20th century
Starting in 1918, the Wisconsin Highway Commission erected highway numbers along state-maintained roadways. The highway across the state from St. Croix Falls to Armstrong Creek was numbered WIS 14 at that time. The remainder of what is now US 8 was unnumbered secondary highways, and WIS 14 continued north of Armstrong Creek to Florence. When Michigan numbered its highway system the following year, the future US 8 was not included in the system. In Minnesota, US 8 would follow what was Constitutional Route 46, which was designated in a state constitutional amendment adopted on November 2, 1920; that roadway originally ran between Forest Lake and Chisago City through Wyoming.

The first changes to the routings of the predecessor highways were made by Wisconsin by 1920. A series of curves were added between Turtle Lake and Barron adding "stair steps" to the routing while similar jogs were removed near Cameron, Weyerhauser, Hawkins and Prentice. WIS 14 was rerouted between Rhinelander and Pelican Lake to run via Monico, and WIS 38 (the future US 141) was extended northward from Wausaukee to terminate at the state line near Niagara. The realignment between Rhinelander and Pelican Lake was shown as reversed by 1922. By 1925, the highway in that area was again rerouted to run directly from Rhinelander to Monico, but instead of turning south to Pelican Lake, it was run directly to Crandon. That same year, WIS 14 was extended eastward from Armstrong Creek to Pembine and northward to Niagara. The north–south section, previously numbered WIS 38, was also redesignated as part of WIS 57.

US 8 was created with the beginnings of the United States Numbered Highway System on November 26, 1926. The highway was originally shown on maps running between Forest Lake, Minnesota and Powers, Michigan. At the time, its planned routing was not previously designated as part of the State Trunkline Highway System in Michigan. The trunkline connection from Quinnesec south into Wisconsin was part of M-57, which met WIS 57 at the state line. US 8 ended at WIS 57 in Pembine at the time, with no connection into Michigan shown on official maps. A map by the American Automobile Association does show the highway continuing east through Faithorn and Hermansville in Michigan to end at US 2. The Wisconsin Highway Commission previously indicated an unnumbered state highway on their 1925 state map that connected Pembine with the Menominee River near Hermansville. A later extension in 1927 moved US 8 to run along US 141, which had replaced WIS 57 and M-57, ending in Quinnesec at US 2. By the next year, the highway was shifted to end in Norway, utilizing a separate crossing of the Menominee River to enter Michigan.

In 1931, US 8 was extended south from Forest Lake into downtown Minneapolis. West of the Rhinelander area, US 8 and US 51 overlapped for about 8 mi as US 8 jogged northward along US 51. This concurrency was altered in 1934, and two years later the short east–west section of US 8/US 51 was removed when changes to US 51's routing were finished in the area. A jog in the routing near Almena was removed in 1937 when Wisconsin rerouted the highway to a more direct alignment in the area.

The last segment of US 8 in Wisconsin was paved in 1937 between Cavour and Armstrong Creek; the highway in Minnesota was paved in its entirety by 1940. Near Hawkins, a pair of sharp curves near the Rusk–Price county line were removed as the State Highway Commission realigned the highway to follow a straighter course. The US 8/US 51 concurrency was altered the next year to a shorter overlap running southward near Heafford Junction. The former routing of US 8 was redesignated County Trunk Highway K (CTH-K) after it was transferred back to county control.

Starting around the year 1955, US 8 was moved to a more direct routing between Forest Lake and Chisago City; US 8 replaced MN 98 along Legislative Route 98. The former routing between Wyoming and Chisago City along Constitutional Route 46 was then redesignated MN 98 until it was decommissioned in the late 1990s.

As late as 1959, the Michigan State Highway Department still had plans to build the section of US 8 west of Hermansville to the Menominee River. The control section atlas published on January 1, 1959, showed this segment of highway on the Menominee County map, complete with a control section number. The section of highway is shown as "proposed" or "under construction". However, a new bridge was built over the Menominee River to carry the highway across the Michigan–Wisconsin state line near Norway in 1966. WisDOT still shows the section of highway needed in their state to extend US 8 to the original eastern terminus in Michigan on internal maps. The December 31, 2004, edition of their Official State Trunk Highway System Maps shows this section as a "mapped corridor".

In the late 1970s, with ongoing construction and completion of the I-35W freeway in Minnesota, US 8 was routed along I-35W; US 8 was truncated again by 1981 to its current terminus in Forest Lake. The section in New Brighton is currently known as Old Highway 8.

WisDOT built a bypass of the city of Rhinelander during the early 1990s; the new highway was constructed south of town as a new two-lane highway that opened to traffic by 1993. The former route through downtown Rhinelander and near Clear and George lakes was redesignated as Business US 8 (Bus. US 8).

21st century
In 2002, US 8 was widened from two lanes to four lanes with a grass median between North Rifle Road and WIS 47 near Rhinelander, Wisconsin. At the time, officials with WisDOT had plans to extend the four-lane divided highway as far west as US 51 near Tomahawk. Problems related to wetlands in the construction area and bad weather pushed completion of the project back almost a year. Contractors had to install metal sheeting to stabilize the marshy ground. Originally scheduled to end in late 2002, the project did not finish until August 2003. The delays and additional work increased the price tag of the project from the original $4.5 million (equivalent to $ in ) to $6.0 million (equivalent to $ in ). A section of the project was only designed for 45 mph speeds for safety reasons. The design also allowed planners to limit the amount of land needed for the expansion.

Bill and Jerri Osberg sued the state and seven other parties in April 2003 over runoff from the construction, claiming that it killed hundreds of trees and polluted ponds on their property. Later investigation uncovered damage to wildlife habitat in the Wisconsin River. Included in the original lawsuit were six individual WisDOT employees, the primary contractor and a local pet supply company. The court of appeals partially upheld a ruling by the district court dismissing the employees and the contractor from the lawsuit in March 2006. The pet supply company was reinstated in the case by the appeals court. The couple settled their claims, and the state pursued the matter against Pagel Construction in a related lawsuit. WisDOT alleged that the contractor did not follow proper erosion controls and failed to remediate the erosion damage to the Osbergs' property. The state wanted the construction company to forfeit their $70,000 retainer (equivalent to $ in ) and pay damages of $150,000 (equivalent to $ in ). Pagel Construction faulted WisDOT's erosion control plan and said that the state's engineers controlled the project and was seeking the return of its retainer. In September 2007, a jury ruled in favor of Pagel Construction and awarded them $70,898.13 in damages (equivalent to $ in ).

Future
WisDOT has completed the environmental studies of bypasses of Barron and Cameron in Barron County. These bypasses would form a continuous expressway through the area. No funding has been identified to complete the projects. The entire length of US 8 in the state has been classified as a North Country Corridor in the Connections 2030 Plan by the department. This designation marks the highway as a priority in "continued safety, enhanced mobility and efficiency" as well as "modernization to correct outdated infrastructure design".

Business route
Business U.S. Highway 8 (Bus. US 8) in Rhinelander, Wisconsin, was a locally maintained business loop highway routing through the central business district of the city. The route was designated when US 8 was shifted to a bypass of downtown in 1992. The former routing of US 8 through the area was designated as a business loop, and it was turned over to the city and county for maintenance. The local authorities erected signs along this route to designate it as a business loop of the main highway south of town. The signs along the road were scheduled to be removed on July 1, 2005, when the business loop was to be redesignated CTH-P.

Before the signage was removed, Bus. US 8 started at the western junction of US 8 and WIS 47. The business loop ran east from this intersection along Kemp Street, crossing the Wisconsin River north of the convergence with the Pelican River. The loop jogged north along Oneida Street for three blocks and turned east again on Lincoln Street. East of town, Bus. US 8 intersected WIS 17 and turned to the southeast. Outside of town, the business loop ran through wooded terrain and turned south near Clear Lake. Near the larger George Lake, the roadway curved back east along the lake's southern shore, running parallel to the main highway before turning south to connect to the main highway. At this intersection with US 8/WIS 47, the business loop ended after a total run of 7.1 mi.

title: U.S. Route 8


text:
Template talk:Red

Red links
Red links mean an article does not exist. Please do not mislead people by using this confusing template to make links red when they should not be. I've removed it from Template:Cleanup. Angela. 03:02, Aug 8, 2004 (UTC)

Edit request
editprotected

Please remove the usage section and replace it with the  template as I've created a documentation subpage at Template:Red/doc. A specific description of the request follows below. Thanks.

Change this:

Usage
My <nowiki>&#123;&#123;red|color&#125;&#125;</nowiki> text. Produces: &nbsp;&nbsp;My color text.

ar:قالب:أحمر es:Plantilla:Rojo sr:Шаблон:Црвено vi:Tiêu bản:Đỏ

To this:

--Lightsup55 ( T | C ) 17:31, 23 January 2009 (UTC)
 * Yes check.svg Done--Aervanath (talk) 18:12, 23 January 2009 (UTC)

Edit request (again)
Hate to do this to another administrator, but there is an empty line at the very top that needs to be removed. It is causing a new line to be placed on pages where it is used.

In other words, we don't want this to happen when the template is used.

Change this:

To this:

--Lightsup55 ( T | C ) 20:24, 23 January 2009 (UTC)
 * Seconded. (See look at my sig)--> -- [[ axg|undefinedSpecial:Contributions/AxGtalk  |undefined]] 21:33, 23 January 2009 (UTC)

 * This change doesn't need consensus. Besides, signatures should not have templates in them for various reasons. --Lightsup55 ( T | C ) 22:20, 23 January 2009 (UTC)
 * Yes check.svg Done - Rjd0060 (talk) 02:30, 24 January 2009 (UTC)

Some misplaced comments relating to Template:Red (band)
"Breathe Into Me" now has a wikipage. Can you please add the link: Breathe Into Me

Thank you.

ChauffWiki (talk) 15:00, 12 October 2010 (UTC)
 * Is suspect you are on the wrong page. This is the talk page for Template:Red. — Martin (MSGJ · talk) 17:05, 12 October 2010 (UTC)
 * Think you are looking for Template:Red (band). — Martin (MSGJ · talk) 17:07, 12 October 2010 (UTC)

In the Navbox, "Already Over" should be styled like this for wiki link: Already Over —Preceding unsigned comment added by 12.148.86.3 (talk) 14:47, 13 October 2010 (UTC)

Edit request as of 01:24, 20 January 2020 (UTC)
Please change: to: Edit request basis filled by WikiLevy on behalf of – 184 . 254  —Preceding undated comment added 01:24, 20 January 2020
 * Pictogram voting comment.svg Note: if you decline or accept this edit please notify me on my talk page. – 184 . 254  —Preceding undated comment added 01:37, 20 January 2020
 * Yes check.svg Done Izno (talk) 02:28, 20 January 2020 (UTC)

title: Template talk:Red


text:
Talk:Father's Day

Welcome
The gov't of the Kingdom of Saudi Arabia is theocratic where state affairs are governed by the king but lifestyle of the Saudis is controlled by religious elders (read, Muslim sheikhs) who would detest observance of anniversaries other than the two Islamic holidays, viz: Eid Al-Fitr & Eid Al-Adha. Never had I heard Fathers Day (Arabic, Yawm Al-Ab يوم الأب) for three decades that I lived there. Hence, it is absolutely a mistake to include Saudi Arabia as among countries observing Fathers Day on the 3rd Sunday of June. Do rectify to add more credibility on the article. Tomdec78 (talk) 01:52, 21 June 2021 (UTC)

Celebrations of one's individual father (singular) vs. celebration of fathers (pl)
"Father's Day is a holiday of honoring fatherhood and paternal bonds, as well as the influence of fathers in society." Seems inaccurate. The holiday is specifically "Father's Day" a singular possessive, not "Fathers' Day" a plural possessive. This would indicate it is about each individual father and not the collection of all fathers.

Father's Day is derived from Mother's Day. Anna Jarvis, who created and championed Mother's Day specifically calls out that "Mother's" should "be a singular possessive, for each family to honor its own mother, not a plural possessive commemorating all mothers in the world." (https://en.wikipedia.org/wiki/Mother%27s_Day). Mpeachey (talk) 18:33, 2 May 2023 (UTC)

 * As with many other words and terms, meaning changes over time, and differs around the world. I'm in my 70s and can long remember discussion of the day being about all mothers, not just one's own. And there's more. Mother's Day is very soon here in Australia, and I heard a discussion this morning about how this day should be focussed given the modern day acceptance of many different structures of families. Obviously some families don't include mothers, for many different reasons - two fathers, or death of a mother, for example. The same obviously applies to fathers. There isn't a rigid, single, global definition. HiLo48 (talk) 03:06, 3 May 2023 (UTC)

title: Talk:Father's Day


text:
Talk:Mauthausen concentration camp

"Melk concentration camp" listed at Redirects for discussion
A discussion is taking place to address the redirect Melk concentration camp. The discussion will occur at Redirects for discussion/Log/2020 June 10 until a consensus is reached, and readers of this page are welcome to contribute to the discussion. buidhe 11:30, 10 June 2020 (UTC)

Mauthausen
This was German camp 85.255.234.39 (talk) 19:41, 5 January 2022 (UTC)

I believe the following should be added for BRUTAL context; from the book "The 186 steps": "Those who visit the Mauthausen quarry today, don't see the same thing, for since then, the steps have been redone - a real stairway, cemented, and regular. At that time, they were simply cut with a pick into the clay and rock, held in place by logs, unequal in height and tread, and therefore extremely difficult, not only for climbing but also for the descent. Stones rolled under our wooden-soled sandals, and we were forced to keep moving at a very rapid pace.

The work consisted of carrying up a stone of considerable size and weight, along the 186 steps, after which there was still a considerable distance to cover. The man who chose a stone found to be too small was out of luck. And all of this went on at the rate of eight to ten trips per day. The pace was infernal, without a second's rest."

https://www.amusingplanet.com/2017/01/the-infamous-mauthausen-stairs-of-death.html -NotBond007 — Preceding unsigned comment added by NotBond007 (talk • contribs) 01:18, 17 February 2023 (UTC)

Revert
I point out that per WP:ONUS, just being verifiable is not sufficient reason to keep material in the lead. Your preferred version puts excessive weight on the official grade of the camp. However, this grade was only on paper and in practice, the grade of a camp does not correlate well with the actual conditions or death rate (Auschwitz was consistently deadlier despite being rated a grade II camp). The prominent position in the lead can mislead the reader into thinking that this is an important and accurate measure of the camp's severity. Furthermore, the entire Mauthausen system cannot be described as "extermination through labor", as it included camps with a low death rate or even where no deaths occurred. The entire concept of extermination through labor is controversial for a variety of reasons and should not be given excessive weight or presented in a decontextualized manner. (t · c)  buidhe  17:00, 15 February 2022 (UTC)
 * Colleague, I see your logic, but these issues must come from reliable sources. In particular the controversy over "Extermination through labour" is not covered in this article. Therefore these substantial changes must be supported by reliable sources or as a minimum by other Wikipedia articles, otherwise they are not easily verifiable.
 * Second, I know only well that scholarly sources may err and may be superceded by more recent research, but you cannot dismiss cited referenced by wikipedian's opinion. If you think that some sources err or obsolete or fringe, etc., you have to provide other sources, not just an "alphabet soup". By the way WP:ONUS is inapplicable, because I am not seeking to include some text. Instead, you are seeking to delete a piece which was present in the article for a long time. Therefofre the onus is on you to prove that all previous wikipedians were wrong. Loew Galitz (talk) 18:09, 15 February 2022 (UTC)
 * P.S. I am not an expert on this issue, I merely noticed major changes in pages on my watchlist. Therefore I will not engage further in this discussion, let us see what other wikipedians will say. Unfortunately with a sorrow I notice that the participation of active contributors in Wikipedia dwindled greatly and 90% of changes in my watchlist are from wikignomes, with only cosmetic changes which do not contribute to knowledge. Therefore I anticipate you changes will stay regardless. Good luck. Loew Galitz (talk) 18:17, 15 February 2022 (UTC)
 * Regardless of concerns about accuracy, I do not see why the removed content is WP:DUE in the lead. The lead must be a summary of the body and neither the official grade of the camp, nor the concept of "extermination through labor", are discussed in the body, so they should not be in the lead.
 * The claim that "Unlike many other concentration camps, which were intended for all categories of prisoners, Mauthausen was mostly used for extermination through labour of the intelligentsia – educated people and members of the higher social classes in countries subjugated by the Nazi regime during World War II." does not even seem to be factually accurate. I cannot access the cited sources but based on the ones I have access to, Mauthausen also held all classes of prisoners, including many Soviet POWs who would not have been any more educated than the average Red Army soldier, and homosexual prisoners who were disproportionately from the lower classes. (t · c)  buidhe  18:41, 15 February 2022 (UTC)

After a brief reading, I figured out the issue with "grade III". The reason of our misunderstanding about its inclusion in the lede is that over time the functionality of the camp changed somewhere in 1942. Before that it was indeed a "tough" camp for political enemies hence assigned grade III. But gradually it was turned into a "regular" (if I may say so) labor camp, for which workforce was important. But the classification did not change. (The brutality towards emaciated Muselmänner (and to others) did not change, but there was no longer intentional starvation.) That's my summary. I think this is an important consideration to be added, but I do not intend to work on the article. Loew Galitz (talk) 19:23, 15 February 2022 (UTC)

20 years later sentence
I'm not sure what this sentence is trying to say:

Mauthausen was a concentration camp that first appeared in 1938, and the original Mauthausen camp was not situated precisely on the same spot as the latter more commonly known Mauthausen opened 20 years later.

It seems to imply there was one Mauthausen concentration camp in 1938, and then another in 1958 or possibly one in 1918 and one in 1938, I'm pretty sure neither meaning is the intended one, so it would be good if someone knowledge-able could clean this sentence up. 173.71.95.77 (talk) 15:07, 16 January 2024 (UTC)

title: Talk:Mauthausen concentration camp


text:
Talk:Ergodic literature

Cleanup efforts
Most of the works listed here as ergodic literature are clearly NOT ergodic literature based on Espen Aarseth's definition and the term's use in academic texts. This article really needs clearing up - I'll try and contribute but can't right now. [http://grandtextauto.gatech.edu/2005/08/12/clarifying-ergodic-and-cybertext/ Noah Wardrip-Fruin's discussion of what cybertext and ergodic really mean would be a useful source in editing this, but of course it's Aarseth's book Cybertext that is the primary source, as this is where the term was coined and defined. Future developments and uses of the term should be discussed too, which requires more work. For now I've removed the most obviously false examples of ergodic literature and I've flagged the article as needing attention from an expert. Lijil 11:59, 2 September 2006 (UTC)

OK; I've fixed a lot - deleted the bits about how works with some non-linear chronology can be ergodic. I deleted the confusing list of examples and put in a list of texts Aarseth refers to as ergodic instead (from Noah's discussion of the book) and added both Cybertext itself and Noah's discussion to the list of references. Plenty left to do. --Lijil 13:11, 2 September 2006 (UTC)

Questions
Does "The Sound and the Fury" by Faulkner qualify as Ergodic? It's read front-to-back, but then again so is Burroughs, and it requires considerable effort by the reader to keep track of where you are in time -- which often changes midparagraph -- and which characters are speaking. And then there's the name changes.

Just added the links to FF (which seemed appropriate from the definition) and the pieces of "Ergodic literature" I found from another article online. I'm still not quite clear on what Ergodic literature is? If were reading the copy of the Count of Monte Cristo here then would it count as Ergodic Literature, since I need to click on a hyperlink to move through the chapters? If someone reads something by Will Self and keeps needing to reach for a dictionary does this turn Will Self's book into Ergodic Literature? These examples might seem Pathological, but 253 exists both as an novel and as a [ http://www.amazon.com/exec/obidos/tg/detail/-/0312182953/qid=1091932786/sr=1-4/ref=sr_1_4/002-0521382-4667201?v=glance&s=books proper book]. One can read the physical book sequentially, no flicking back and forth from the descriptions of interelated passengers is necessary - but is quite irresistable. Is the physical book Ergodic? Is Ergodic Literature only intended to refer to HyperFiction?

A Sample Chapter from Cybertext: Perspectives on Ergodic Literature from which the term Ergodic seems to have come from. I would try and answer the questions I have asked by trying to read it, but it's late and it seems quite dense - but if anyone else wants to tighten up this article that might be a place to start. Number 0 03:04, 8 Aug 2004 (UTC)

 * Hopefully some of these questions are answered by the slightly improved definition ont he article page - it still needs more work. Ergodic literature is a very specific term and you absolutely should read Aarseth's book to understand it. Lijil 07:45, 8 September 2006 (UTC)

I Ching
What "critics of ergodic literature" consider the I Ching to be an example of the style? It wasn't constructed to be read as a text; unless someone can cite this claim it should be deleted.

 * Espen Aarseth explicitly gives the I Ching as an example of ergodic literature. I'll add a page reference when I'm back at the office with the book. --Lijil 11:59, 2 September 2006 (UTC)

House of Leaves
Has anyone else read House of Leaves by Mark Z. Danielewski? Its a pretty good example of ergodic literature, and well worth reading. And do the muds really count? It would seem to me they are no more this than any sort of video game... Sklarface 05:54, 8 September 2006 (UTC)

 * House of Leaves is a great book, and I suppose it counts as ergodic literature as much as Apollinaire's Calligrammes, which are also characterised by their unusual layout, requiring the reader to move his/her eyes in different ways than a conventional top to bottom, left to write text. I don't think we should simply add more and more examples, though - I think the list will get entirely out of hand (again) and that a better strategy is to work on clarifying the definition as given. MUDs are quite definitely an example of ergodic literature, and Aarseth devotes a whole chapter to them in the book that defines ergodic literature - ergodic literature is literature (written words) that require a non-trivial effort to traverse on the part of the reader. Print books with odd layouts are just one kind, and not the most common kind, either. Lijil 07:45, 8 September 2006 (UTC)

 * Also with the house of leaves (Not so obvious on the surface) are the codes and sequences contained within. Some paragraphs and lines are spaced in different formations to symbolize morse code (SOS), you need to hold four pages together and up to a light to reveal a picture, some reconstructing of pages using "codes" provided by the characters change the meaning of a passage entirely, the list goes on.  I am working on a book of Ergodic Literature myself and find it tough to stick within the guidelines.  —Preceding unsigned comment added by 24.85.75.221 (talk) 01:23, 27 August 2008 (UTC)

 * Besides being specifically cited in the Aarseth text, MUDs-- especially role-playing enforced MUDs-- exist to do little more than let a group of people tell a narrative. There's a hack and slash framework built into a lot of them, but the storyline in an RP MUD is considered the whole point of the game. JoshOak (talk) 21:30, 28 January 2010 (UTC)

 * As of today, I no longer see any reference to House of Leaves in the article text, but I also don't see any recent edits that deleted it. Am I missing something? The book itself is great, and a good contemporary (relative to the application of the term "ergodic" to literature) example of the theory. ExecutorElassus (talk) 14:17, 4 March 2012 (UTC)

Clarification
Does "ergodic" require that the text be dependant on the reader? For instance, would the copious note-taking required to follow Dream of the Red Chamber or similarly populous novels count as a "non-trivial effort"? Again, would a comic with ambiguously placed panels that do not immediately suggest an order, but still have an intended order, require "non-trivial effort"? Rozencrantz 05:43, 11 October 2006 (UTC)

Puzzles
What about puzzle books and those puzzles where you put together blocks of letters and the final result spells a quotation?

Mathematical proofs?

Riddles and such where you have to rot-13 or turn the page to check the answer?

 * The same goes for various children's books, e.g., pop-up books, choose-your-own-adventures, and (especially!) things like [ http://www.amazon.com/Barbie-Match-Fashions-Sectioned-Flip/dp/157584334X/ref=sr_1_1 Barbie Mix and Match Fashions Sectioned Flip Book]. I can think of a handful of published cybertexts that use almost the same exact traversal mechanics.

 * I think the larger issue here is ergodic text versus ergodic literature. To illustrate my point, is a TV commercial considered film? If I can relate to the guy on the TV screen with a headache, or empathize with the mom scrubbing soap scum off the shower tile, or feel for the characters in the Zoloft commercial, then why is it in a different category than a short film? In the hegemonic structure, the only way we justify the distinction, of course, is by placing requirements on the impetus or motive that precipitates the end result. Therefore, commercially motivated works don't count; works associated with mathmematics, science, and research do not count; entertainment doesn't count.

 * The main problem with this method of classification is that it does not accomodate works with multiple, unclear, or missing motivations (e.g., video games, multi-authored works, computer-assisted works, found poetry) or works that bridge typically disparate audiences (e.g., "mash up"-type new media projects). Perhaps not coincidentally, it is these same works that comprise the present frontier of literature. AdamSap (talk) 18:37, 16 December 2007 (UTC)

 * I think the point is that puzzles, proofs, riddles and pop-up books do not have a narrative. — Preceding unsigned comment added by Geryhall31 (talk • contribs) 21:15, 2 February 2016 (UTC)

Other uses of "ergodic"
The current article makes it sound like the word "ergodic" was created solely for this context. However, in mathematics and science there is the Ergodic hypothesis and Ergodic theory, as well as Ergodic (adjective) - which I presume predate the use of the term for literature. Some mention of the connection between the use of the term in math/science contexts and literary contexts is warranted - even if it goes no deeper than saying that there is no connection and that none was ever intended. -- 128.104.112.147 (talk) 16:37, 5 September 2008 (UTC)

The Ergodic principle is quite simple really. It is an important statistical concept in thermodynamics (see Wikipedia article!). The idea is that the time average is the same as the ensemble average. To give you an example, the average position of one molecule in an empty room (not a single other atom or molecule in the room) over time (given enough time for the molecule to explore all the room) is the same as the average position of a dilute gas of molecules filling the room : any spot in the room is as likely to be occupied by a molecule as any other. I hope this makes sense. It is a bit of random concept to introduce in Literature! I believe part of the interest in thermodynamics from the Literary community comes from the very catchy second law of thermodynamics (which basically states that all isolated systems tend to greater disorder) AlineApple (talk) 08:43, 23 May 2010 (UTC)

Article Fails to Define Ergodic
IMO this still needs major work, not from the perspective of whether certain examples are correct or not, but from the perspective of DEFINING THE TERM "ERGODIC". Surely this is the major point that needs to be dealt with before the article can serve any useful purpose to the general Wikipedia reader?

After reading the article, I still have no clear idea what "ergodic" means. I'm not unintelligent, so I believe the fault lies not in my comprehension skills, but in the article itself. A good starting place might be to parse the "most commonly cited definition" instead of simple quoting it and then immediately moving on to discuss variations.

Simply put, if you're going to have a Wiki page be a resource for the uninitiated, you probably should explain the concept clearly before going on to discuss the minutiae thereof. R0nin Two (talk) 01:49, 26 July 2011 (UTC)

My thought as well, ten years later. Fourthark (talk) 04:15, 14 November 2021 (UTC)

Confusing article
This is the truest statement in this entire article.
 * "It has been argued that these distinctions are not entirely clear..."

 * Just a question: Does this mean that every text in Braille is "ergodic"?  Liz  Read! Talk! 18:36, 31 August 2013 (UTC)

 * I don't think that people reading with Braille find it non-trivial it's no different to a sighted person who can read with their eyes. — Preceding unsigned comment added by Geryhall31 (talk • contribs) 21:36, 2 February 2016

Another possible example
Is James Joyce's Finnegans Wake considered an example of ergodic literature? Are there any reliable sources that discuss whether to include/exclude it from that genre? -- llywrch (talk) 05:40, 26 June 2014 (UTC)

I can find by googling "Finnegans Wake ergodic" several book references to not only Finnegans Wake but also Joyce's earlier Ulysses as examples of ergodic literature. By any measure these books fit both Espen's definition of ergodic (non-trivial effort) and the idea of hypertext literature. Espen has a couple of references to James Joyce in Cybertext but does not reference FW or Ulysses directly. So yes, I think Finnegans Wake definitely qualifies as ergodic. Simon9 (talk) 06:01, 30 July 2014 (UTC)
 * Here's another possible example: Giorgio de Chirico's Hebdomeros. Or does it only fall in the category of surrealist literature?
 * Jacques Derrida's Glas? — Preceding unsigned comment added by 2603:7000:39F0:8EC0:C4E5:B642:4D7F:E5BD (talk) 18:23, 20 June 2024 (UTC)

Interactive narration
I propose changing the name of this page to Interactive narration, and to clarify the terminology. — Preceding unsigned comment added by Geryhall31 (talk • contribs) 13:54, 1 February 2016

I disagree. My understanding of Ergodic literature as a medium is that the literature exists, and can be consumed, in any order. It requires no direct interaction on the part of the reader to jumble the text -- it cannot be un-jumbled. If I understand the notion of "Interactive narration," it is something that requires a person to specifically choose a direction to read it in, often with a given starting point and a perceived ideal goal. The I Ching has no starting point. A MUD has no table of contents. I believe this article lists several things which perhaps do not actually qualify as Ergodic literature, but that doesn't mean the title is wrong, only the content needs to be refined. This is a complex topic to understand effectively, as it turns out. Skotte (talk) 17:40, 11 December 2023 (UTC)

 * I agree that the page shouldn't be renamed, but I do think it would help to make Aarseth's book a separate article and diversify sources for this text. What do you think?
 * I'll be happy to contribute to one or both once I'm more familiar with the literature myself; faceted search on JSTOR ( in a subset of journals for non-mathematical disciplines) turned up >150 results accessible through my public library. – spida-tarbell ❀ (talk) (contribs) 01:16, 28 January 2024 (UTC)

title: Talk:Ergodic literature


text:
Talk:ASEAN

Map of ASEAN countries is incorrect
In the quick facts section, there is a world map with the ASEAN countries highlighted in dark green. In this map, Papua is highlighted dark green, but it is not an ASEAN country. The map should be corrected. Wmcoco (talk) 11:32, 19 August 2023 (UTC)

 * Additional note: The maps under the headings "Member states" and "Relations with other blocs" similarly include Papua incorrectly. Papua has ASEAN observer status, as does East Timor. East Timor, in contrast, is not highlighted as a member state in these maps. Wmcoco (talk) 11:41, 19 August 2023 (UTC)
 * I am not sure what the quick facts section is, but the Member states and Relations with other blocs maps appears correct to me. CMD (talk) 02:54, 21 August 2023 (UTC)
 * My apologies. You are correct, I withdraw my above comments. (The quick facts section is the pulldown information section - the information is first revealed when you click the downward arrow - near the top of many Wikipedia pages.) Wmcoco (talk) 11:23, 24 August 2023 (UTC)

Map of ASEAN is incorrect
East Timor is highlighted in dark green despite not being officially a member yet. Proximaprotogen (talk) 16:56, 7 January 2024 (UTC)

 * East Timor does not appear to be green in any of the maps at the moment, please check if clearing your cache helps. CMD (talk) 02:15, 8 January 2024 (UTC)
 * Someone must have changed it after I posted that I comment Proximaprotogen (talk) 11:08, 16 January 2024 (UTC)
 * I appreciate your observation. It seems there might have been changes made to the map after your initial comment. CMD suggests clearing your cache to see if that resolves the issue. If the map is still showing East Timor as dark green, it could be a technical glitch or a recent edit by another user 207.96.13.213 (talk) 18:58, 23 January 2024 (UTC)
 * It became dark green againhttps://en.m.wikipedia.org/wiki/File:Association_of_Southeast_Asian_Nations_(orthographic_projection).svg Proximaprotogen (talk) 09:03, 6 March 2024 (UTC)

ASEAN member list is outdated
There are many countries omitted from the list 2402:E280:4116:299:CB6:C6D8:4D23:FC81 (talk) 15:12, 2 February 2024 (UTC)

title: Talk:ASEAN


text: User talk:68.51.145.27

title: User talk:68.51.145.27


text: Wikipedia:WikiProject Tree of Life/taxobox usage (multi-template)