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Radiation Oncology/Sarcoma/Ewing's sarcoma

Ewing's Sarcoma

Epidemiology

 * Tumor of neuroectodermal origin, part of the Ewing Sarcoma Family of Tumors
 * Usually presents in adolescents (40%), but 30% in <10 year olds
 * Second most common bone tumor in children, after osteosarcoma
 * Approximately 225 cases annually in U.S.
 * Primarily in white children; black and Asian children rarely affected

Clinical Presentation

 * Localized pain and swelling
 * Systemic symptoms (fever, low appetite, weight loss) in ~30%
 * Distribution
 * Lower extremity 40-45% (femur 22%, tibia 11%, fibula 9%)
 * Pelvis 20-25%
 * Chest wall 15-20%
 * Upper extremity 10% (humerus 10%)
 * Metastatic disease (20-25%)
 * Primary spread is hematogenous
 * Most commonly to lungs, bones, BM, soft tissue, brain, spine
 * Bilateral bone marrow biopsy part of staging, regardless of tumor size

Radiologic Findings

 * Should include bone scan, CXR, CT or MRI of primary, CT of chest
 * Plain films show "onion skinning" (soft tissue mass growing out from the bone, giving rise to multilamellated periosteal reaction) vs "sunburst" pattern seen in osteosarcoma.

Staging

 * Please see the bone tumors staging page

Pathology

 * Small round blue cell tumor, likely arising in the bone marrow
 * Fusion between EWS gene and a partner gene which presumably dysregulates cell growth
 * t(11;22) EWS-FLI1 (85%)
 * t(21;22) EWS-ERF (10-15%)
 * Other EWS fusions occur rarely (ETV1, E1AF, FEV)

Prognostic factors

 * Disease site: non-pelvic is favorable, with distal, ribs and other having the best prognosis. Pelvic site is unfavorable. Proximal sites are intermediate.
 * Age: younger is favorable
 * Size: >8cm is unfavorable
 * Labs: anemia, elevated ESR, leukocytosis, and elevated LDH associated with worse prognosis
 * Not prognostic: sex and time from onset of symptoms

Treatment Overview

 * Ewing's sarcoma is essentially an occult metastatic disease, and chemotherapy is the backbone of treatment
 * Radiation alone had cure rate ~10%, with majority failing distally
 * Chemotherapy is typically given for 12-15 weeks prior to local therapy
 * Local control is imperative, either with surgery, or radiation therapy, or both
 * No randomized studies comparing the two treatment approaches
 * Surgery favored if complete resection is feasible without significant morbidity and functional loss
 * Radiation favored for central lesions
 * Radiation dose
 * Doses >60 Gy result in unacceptable risk of secondary bone malignancies
 * Doses <40 Gy have unacceptable local failures
 * Currently, ~45 Gy are given for microscopic disease and ~55.8 Gy for gross disease (DeVita 8th ed)
 * Whole lung radiation used for consolidation after chemotherapy

Chemotherapy regimens

 * Standard 5-drug U.S. regimen (VCD + IE): vincristine, doxorubicin, and cyclophosphamide, alternating with ifosfamide and etoposide x48 weeks
 * Original IESS regimen (VAC): vincristine, actinomycin D, cyclophosphamide
 * VAC + ADR - vincristine, actinomycin D, cyclophosphamide + adriamycin

Localized disease

 * St. Jude (1978-88) -- used chemo before surgery
 * Prospective, non-randomized. 60 pts. Localized osseous Ewing's.
 * Induction chemo (ACx5) -> Resection (if possible) -> RT with concurrent chemo -> more chemo (total 57 wks).
 * RT to initial (pre-chemotherapy) osseous tumor and residual soft tissue tumor extension. 3 cm margins. No RT given if resection with negative margins. 35-41 Gy for positive margins. 35 Gy for those with CR after chemo. 50.4 Gy for those with residual tumor after chemo or a tumor >8 cm initially. 1.5-1.8 Gy/fx. Chemo consisted of VCR/DAC during RT, followed by CYC/ADR and VCR/DAC.
 * PMID 1938559, 1991 — "Ewing's sarcoma: local tumor control and patterns of failure following limited-volume radiation therapy." Arai Y et al. Int J Radiat Oncol Biol Phys. 1991 Nov;21(6):1501-8.
 * 5-yr EFS 59%, similar to other studies. 64% achieved CR to induction chemo. LC 68% at 5-yrs. LC depended on tumor size, +/- 8 cm.

 * POG 8346 (1983-88)
 * Randomized. 178 pts. Osseous Ewing's only (excluded PNET and extraosseous).
 * Induction chemotherapy: CYC/ADR x 5.
 * Assess response:
 * If PD, XRT and salvage chemo
 * If CR/PR and tumor involved expendable bone (proximal fibular, distal 4/5 of clavicle, body of scapula, iliac wing, ribs), had surgery. Received post-op RT for microscopic or gross residual disease.
 * If not receive surgery, received 55.8 Gy RT and randomized to whole bone RT (39.6 Gy + boost with 2 cm margin) vs a tailored, involved field (same as boost).
 * During RT, received VAC chemo followed by weekly VCR. Maintenance chemo given for a total of 50 wks.
 * PMID 9747829, 1998 — "A multidisciplinary study investigating radiotherapy in Ewing's sarcoma: end results of POG #8346. Pediatric Oncology Group." Donaldson SS et al. Int J Radiat Oncol Biol Phys. 1998 Aug 1;42(1):125-35.
 * 5-yr LC for resected tumors was 88% vs 65% with RT alone. No difference in LC between those randomized to whole bone vs involved field. LF was in-field in 62% vs outside in 24%.
 * Conclusion: Most failures are systemic rather than local. Thus, interpretation of local failures is difficult due to competing risks.

Disseminated disease

 * EURO-EWING 99 (1998-2006) PMID 19924786 -- "The value of local treatment in patients with primary, disseminated, multifocal Ewing sarcoma (PDMES)." (Haeusler J, Cancer. 2010 Jan 15;116(2):443-50.)
 * Retrospective. 120 patients. Local treatment of the primary with surgery 22%, surgery + RT 17% or definitive RT 33%. Local treatment of mets surgery 5%, surgergy + RT 7%, definitive RT 27%. No local therapy in 27%
 * Outcome: 3-year EFS 24%; by modality surgery 25% vs surgery + RT 47% vs RT 23% vs no local therapy 13% (SS). 3-year EFS if treatment of primary and met 39% vs either primary or met 17% vs no local therapy 14% (SS)
 * Conclusion: Local therapy of involved sites important for patients with disseminated Ewing sarcoma and should complement systemic treatment whenever possible

Intergroup IESS Trials

 * IESS-III (1988-92)
 * 518 pts. Ewings's, PNET of bone, or primitive sarcoma of bone. Allowed both localized and metastatic (23%).
 * Randomized to VAC+ADR or VAC+ADR alternating with ifosfamide and etoposide.
 * Chemotherapy was given q3weeks x 17 courses, total of 49 weeks. At week 12, radiation therapy or surgery was performed. RT was 45 Gy to initial tumor volume (with 3 cm margin) + 1080 cGy boost = 5580 cGy. For those undergoing resection, RT was to 45 Gy for microscopic residual (with 1 cm margin).
 * PMID 12594313, 2003 — "Addition of ifosfamide and etoposide to standard chemotherapy for Ewing's sarcoma and primitive neuroectodermal tumor of bone." Grier HE et al. N Engl J Med. 2003 Feb 20;348(8):694-701.
 * For non-metastatic pts, 5-yr EFS 69% vs 54% for VAC+ADR+IE vs VAC+ADR; RR=1.6. 5-yr OS 72% vs 61%; RR=1.6. Greater reduction in LR than in distant mets. Greater benefit for large primary tumors or pelvic tumors. For pts with mets, no difference between regimens: 5-yr EFS 22% and OS 34%.
 * Conclusion: improved survival with addition of ifosfamide and etoposide (in non-metastatic pts).

 * IESS-II (1978-82)
 * 214 pts. Localized, non-pelvic Ewing's sarcoma of bone.
 * Randomized to VAC+ADR as high-dose intermittent regimen or as moderate-dose continuous regimen (as per IESS-I). RT given in both arms for all pts except those with resection with negative margins.
 * Chemotherapy given q3weeks (high dose intermittent) or weekly (continuous). High-dose: VA-VC x 6, then VD-VC x 7. Continuous: VC x 6, then VD-VC4-VCA x 7. RT at beginning of chemo.
 * PMID 2099751, 1990 — "Multimodal therapy for the management of nonpelvic, localized Ewing's sarcoma of bone: intergroup study IESS-II." Burgert EO Jr et al. J Clin Oncol. 1990 Sep;8(9):1514-24.
 * Median f/u 5.6 yrs. 5-yr DFS, RFS, and OS 68% vs 48%, 73% vs 56%, 77% vs 63% for high-dose vs continuous. LR in only 9%.
 * Conclusion: improved survival with more aggressive chemotherapy.

 * Intergroup Ewing's Sarcoma Study IESS-I (1972-1978)
 * 342 pts. Localized Ewing's sarcoma of bone, previously untreated. 7 pts treated with amputation were not randomized but were entered on treatment 1.
 * Initially group I institutions randomized to +/- VAC chemo. Changed protocol in 1973 because it was realized that adjuvant chemotherapy was necessary.
 * Randomized 3:2 to 1) RT to primary plus VAC + Adriamycin or 2) RT plus VAC -- group I institutions
 * Randomized 3:2 to 3) RT to primary plus VAC and bilateral pulmonary RT (BRP) or 2) RT plus VAC (same as above) -- group II institutions
 * Chemotherapy given x 6 weeks. Vincristine and cyclophosphamide given weekly and adriamycin given with the last dose. After 6 weeks rest, pts had a 7 week course of continuation therapy that consisted of dactinomycin IV x 5 days followed 9 days later by VCR and cyclophosphamide weekly x 5 weeks. For treatment 1, adriamycin given with the last course in the 7th week of each course.
 * RT treated the entire involved bone to 45-55 Gy (dose depends on age), followed by 10 Gy boost to gross radiographic tumor + soft tissue mass with margin. For pts receiving lung RT, 15-18 Gy given at 150-180 cGy/day.
 * PMID 7029293, 1981 — "Multimodal therapy for the management of primary, nonmetastatic Ewing's sarcoma of bone: an Intergroup Study." Nesbit ME Jr et al. Natl Cancer Inst Monogr. 1981 Apr;(56):255-62.
 * PMID 2213103, 1990 — "Multimodal therapy for the management of primary, nonmetastatic Ewing's sarcoma of bone: a long-term follow-up of the First Intergroup study." Nesbit ME Jr et al. J Clin Oncol. 1990 Oct;8(10):1664-74.
 * Median f/u 6 yrs. 5-yr RFS treatment 1 - 60%, 2 - 24%, 3 - 44%. Similar trend for OS. Worse survival for pelvic sites. No evidence of difference among treatments for pelvic sites. 15% LR overall. DM in 30%, 72%, and 42%. BPR was not effective in preventing lung mets.
 * Conclusion: improved survival with addition of Adriamycin to VAC.

Risk of Second Malignancy

 * St. Judes; 1996 PMID 8874344 -- "Second malignancies after Ewing's sarcoma: radiation dose-dependency of secondary sarcomas." (Kuttesch JF, J Clin Oncol. 1996 Oct;14(10):2818-25.)
 * Retrospective. 266 patients with Ewing's sarcoma. Median F/U 9.5 years (3-30)
 * 16 second malignancies (10 sarcomas, 6 others). Median latency 7.6 years (3.5 - 25.7)
 * 20-year cumulative incidence: 9.2% for any malignancy, 6.5% for sarcoma
 * Dose-response: none in <48 Gy, 130/10,000 for >60 Gy
 * Conclusion: Overall risk of 2nd malignancies similar to other pediatric tumors. RT dose-dependency justifies modification in approach to reduce radiation doses


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Cookbook:Tapas

| Cuisine of Spain

Tapas are often defined as bite-sized Spanish hors-d'oeuvres, and many people think of them as appetizers. Tapas are more than just appetizers; they are an integral part of Spanish cuisine and customs. Tapas originated many centuries ago in the southern region of Spain known as Andalucía.

The most popular explanation for the origin of tapas is that they began when innkeepers began placing saucers or pieces of bread atop their customers' wine glasses as a way to prevent flies from swarming in. "Tapas" is the Spanish word for "cover" or "lid". These small portions of food that were used to cover glasses proved to be a good way of attracting customers into bars, which is why tapas have evolved from a simple piece of bread into more intricate culinary works.

Although tapas originated in the south, they are served in every region of Spain. Some bars serve tapas for free when a drink is ordered, for example, olives or nuts are commonly free of charge.

Tapas are an essential part of Spanish tradition and culture because they bring families and friends together. It is common for Spaniards to gather at bars or bodegas for drinks and conversation while sharing "raciones", or portions of tapas.

There are many different varieties of tapas, but some of the most well known include:

 * Spanish omelette (tortilla de patatas)
 * Pan tomaca (Cured ham and tomato sandwich)
 * Gambas al ajillo

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

title: Cookbook:Tapas


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User:Karl Wick/Test/Foundational Books

A discussion of the goals of this page

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General Chemistry | Organic Chemistry | Physics | General Biology

Mathematics
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Introduction to Psychology | Introduction to Philosophy

History
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English
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title: User:Karl Wick/Test/Foundational Books


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Cookbook:Marinated Green Olives

Green olives marinated in herbs and garlic are very common in Spanish restaurants. They are commonly served free when you order a drink, and are often served with toasted, salted nuts.

Ingredients

 * 2 cups (16 oz/450 g) unpitted large green Spanish olives
 * 7 cloves garlic, peeled and minced
 * 2 bay leaves
 * ½ medium lemon, sliced
 * 1 teaspoon dried oregano
 * 1 teaspoon ground fennel seeds
 * ½ teaspoon dried thyme
 * ½ teaspoon ground cumin seeds
 * ½ teaspoon dried rosemary
 * ½ teaspoon Spanish paprika
 * ½ teaspoon black pepper

Procedure

 * 1) Lightly crush the olives with a mallet, or make slight slits on each olive with a knife, to ensure that the marinade permeates them.
 * 2) Place the olives in a sealable glass jar and add the remaining ingredients.
 * 3) Fill the jar with water and shake well.
 * 4) Marinate at room temperature for several days to a week.
 * 5) Serve the olives with toasted almonds and fresh bread.

title: Cookbook:Marinated Green Olives


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Adventist Youth Honors Answer Book/Vocational/Automobile Mechanics

==1. Properly start an automobile or light truck engine with an automatic transmission and one with a standard transmission. Explain why it is necessary for the engine to have the proper oil, water, fuel, and battery pressures and levels for proper engine operation.==

Starting an Automatic
To start a vehicle with an automatic transmission, sit in the driver's seat and make sure the vehicle is in Park. Insert the key in the ignition and turn it clockwise as far as it will go. The engine should crank. Do not depress the gas pedal. As soon as the engine starts, release the key. To turn it off, turn the key counter-clockwise.

Starting a Manual
To start a vehicle with a manual transmission, sit in the driver's seat and push the clutch pedal all the way in with the left foot. The clutch pedal is the third one from the right, and this is often the one farthest to the left (although some vehicles have the parking brake to the left of the clutch).

Make sure the parking brake has been applied. Inexperienced drivers should also shift the vehicle into neutral so that if the foot slips off the clutch after the engine starts, the car does not move. Even with the vehicle in neutral, it is still important to depress the clutch, as many autos have a switch in the clutch which prevents the engine from starting unless the clutch is depressed. Insert the key in the ignition and turn it clockwise as far as it will go. The engine should crank. Do not depress the gas pedal, but leave the clutch pedal depressed. As soon as the engine starts, release the key. To turn it off, turn the key counter-clockwise.

Importance of Proper Pressures and Levels
Oil keeps the engine lubricated and reduces friction between the moving parts of the engine. Friction causes heat, so if there is insufficient oil pressure in the engine, it will quickly overheat. Running an engine without oil for any amount of time will damage it, and doing so for an extended period will destroy it.

Water circulates through the engine to cool it. Running an engine too hot will damage it.

Fuel is what makes the engine go. If the vehicle has insufficient fuel pressure, the fuel will not flow into the combustion chamber at the proper rate.

The Battery provides energy to run the engine's starter. If the battery's voltage level is low, it may not be able to turn the starter.

==2. Explain the principles of four- and two-cycle engines and the difference between gasoline and diesel engines. Explain the major differences between carburetor fuel systems and fuel-injection systems.==

Four-cycle Engine
A four-cycle engine is so named because it makes four strokes to generate power. These strokes are as follows:
 * 1) Intake Stroke: During this stroke, the piston draws a mixture of fuel and air into the cylinder.  The fuel and air enters through an intake valve which opens during this stroke.
 * 2) Compression Stroke: Once the fuel and air have been drawn into the cylinder, the intake valve close and the piston returns towards the engine's head.  This compresses the fuel.
 * 3) Power Stroke: When the piston reaches the top of the cylinder, the spark plug fires, igniting the compressed fuel and air mixture and causing an explosion.  This explosion causes the gases to expand which powers the piston downwards again.  This is where the engines power (and noise!) comes from.
 * 4) Exhaust Stroke: When the piston reaches the bottom of the cylinder, the exhaust valve opens, and as the piston returns to the top of the cylinder again, the exhaust gases are pushed out.  When the cylinder reaches the top again, the four cycles are ready to repeat.

Two-cycle Engine

Power and Exhaust Stroke: In a two-cycle engine, the spark plug fires every time the piston reaches the top of the cylinder. This is the beginning of the power and exhaust cycle. As in the four cycle engine, the spark plug firing causes a compressed air/fuel mixture in the cylinder to explode, and the expanding gases drive the piston downward. As the cylinder goes down, it compresses another air/fuel mixture inside the crankcase - not inside the cylinder as in the four-stroke engine. The crankcase is the area beneath the piston, and the cylinder is the area above the piston. When the piston nears the bottom of this stroke, it uncovers an exhaust outlet and it also uncovers a passage between the crankcase and the cylinder. The compressed air-fuel mixture in the crankcase then rushes through this passage-way into the cylinder, forcing the exhaust gases out of the cylinder though the exhaust outlet. Some of the air/fuel mixture is also forced out the exhaust outlet, and this unfortunately decreases the engine's fuel efficiency and increases its pollution output. The piston's head is shaped in such a way as to minimize this waste, but it does not entirely eliminate it.

Intake and Compression Stroke: After the piston reaches the bottom of the stroke, it begins traveling upwards again, compressing the air/fuel mixture that rushed into the cylinder from the crankcase during the previous stroke, and simultaneously drawing more air and fuel into the crankcase. By the time the piston reaches the top of the cylinder, the air/fuel mixture is very highly compressed - much more compressed than it was in the crankcase. It is at this point in the cycle that the intake valve closes and the spark plug fires.

Because the crankcase is opened to the cylinder during its operation, oil in the crankcase makes its way into the cylinder where it is compressed and combusted along with the fuel. If this situation were ignored, the engine would soon burn up all its oil, leaving itself unlubricated. The engine would soon get so hot that its parts would fuse together and destroy itself. This is addressed by adding oil to the fuel (often one part oil to sixteen parts fuel). Thus the engine's oil supply is refreshed on every stroke of the piston. This unfortunately increases the pollution levels generated by two-stroke engines.

Gasoline verses Diesel Engines
In many respects, the four-stroke gasoline engine and the four-stroke diesel engine are very similar. They both follow an operating cycle that consists of intake, compression, power, and exhaust strokes. They also share in the same system for intake and exhaust valves. The fuel and air mixture is ignited by the heat generated by the compression stroke in a diesel engine versus the use of a spark ignition system on a gasoline engine. The diesel engine needs no ignition system. For this reason, the gasoline engine is referred to as a spark ignition engine and a diesel engine is referred to as a compression ignition engine.

The fuel and air mixture is compressed to about one-twentieth of its original volume in a diesel engine. In contrast, the fuel and air mixture in a gasoline engine is compressed to about one-eighth of its original volume. The diesel engine must compress the mixture this tightly to generate enough heat to ignite the fuel and air mixture.

The gasoline engine mixes the fuel and air before it reaches the combustion chamber. A diesel engine takes in only air through the intake port. Fuel is put into the combustion chamber directly through an injection system. The air and fuel then mix in the combustion chamber.

The engine speed and the power output of a diesel engine are controlled by the quantity of fuel admitted to the combustion chamber. The amount of air is constant. This contrasts with the gasoline engine where the speed and power output are regulated by limiting the air entering the  engine.

Carburetor verses Fuel Injection Systems
The carburetor serves the following basic functions:
 * 1) The carburetor mixes fuel and air Into the correct proportions for the most efficient use by the engine. The carburetor  also must constantly vary the mixture proportions to meet the engine’s needs as Its speed and load requirements vary.
 * 2) The carburetor regulates engine speed and power output.
 * 3) The carburetor atomizes the fuel as it mixes it with the air.

Fuel injection systems are an increasingly popular alternative to the carburetor for providing   an air-fuel mixture. They inject, under pressure, a measured amount of fuel into the Intake air, usually at a point near the intake valve. Fuel injection systems provide the following advantages.
 * 1) Fuel delivery can be measured with extreme accuracy, giving the potential for improved fuel economy and performance.
 * 2) Because the fuel is injected at the intake port of each cylinder, fuel distribution will be much better and fuel condensing in the manifold will not be a problem.
 * 3) The fuel injector, working under pressure, can atomize the fuel much finer than the carburetor, resulting in improved fuel vaporization.

3. Describe the construction of a typical gasoline engine and explain briefly the function of these units
===a. Engine: crankshaft, connecting rods, pistons, camshaft, valves, oil pump, carburetor, fuel injectors, ignition distributor, fuel distributor, electrical system including alternator, battery, and regulator=== As can be seen in the diagram to the right, the pistons drive the crankshaft via the connecting rods. The connecting rods and crankshaft convert the back-and-forth motion of the pistons into rotary motion.

The camshaft is a smaller rotating shaft with small "bumps" on it called cams. As the cams rotate, they lift and lower the valves at just the right time to allow gasses to either flow into the cylinder or escape from it.

The oil pump moves oil through the engine to keep the internal parts well lubricated.

The function of the carburetor and fuel injector were covered in requirement 3.

The ignition distributor has several jobs to do in the ignition system. First, it must close and open the primary circuit to produce the magnetic buildup and collapse in the ignition coil. Second, it times these actions so the resultant high-voltage surges from the secondary will be produced at the right time. Third, it must establish a timing sequence to direct the high-voltage surges to the proper spark plugs.

The distributor injection system used in automotive diesel engines is classed as a low-pressure system in that pumping, metering, and distribution operations take place at low pressure. The high pressure required for injection is built up by the injector at each cylinder. A suction pump lifts fuel from the tank and delivers it to the float chamber. From here a second low-pressure pump delivers the fuel to the fuel distributor. Fuel passes through the distributor to the metering pump, where it is divided into measured charges. The fuel charges then are delivered back to the distributor, where they are sent to the injectors in the proper sequence.

Electrical system
The alternator is an electrical generator. As the engine turns a shaft in the alternator, it generates electricity to run everything in the car's electrical system, including the headlights, on-board computers, radio, and more. It also recharges the battery.

The battery is used primarily for starting the vehicle. When the car is not running, the alternator cannot generate any electricity, so the battery must do this. It will also power the headlights, radio, and a few other things. The most common way a battery "dies" is when someone leaves the headlights on for too long with the engine off.

The regulator evens out the voltage coming out of the alternator before it is fed to the rest of the electrical system. The voltage from the alternator can vary depending on a lot of different factors, and it is the regulator's job to make sure that none of the other components have to deal with varying amounts of power. Without the regulator, the headlights would brighten and dim as the alternator's voltage varied.

b. Difference between standard transmission and automatic transmission and how the engine torque is transmitted to both kinds of transmissions; the purpose of overdrive
The transmission couples the engine to the drive shaft and has two main functions:
 * 1) Control direction of travel (forward or revers)
 * 2) Provide the operator with a selection of gear ratios between engine and wheels so that the vehicle can operate at best efficiency under a variety of driving conditions and loads.

In a vehicle with a standard transmission the driver selects the desired gear manually. In a vehicle with an automatic transmission the transmission makes the gear selection itself depending on throttle position, vehicle speed, and the position of the shift control lever.

In both cases, engine torque is transmitted to the wheels via a clutch. Automotive clutches depend on friction for their operation, whether it be solid friction as in the conventional clutch (found on a standard transmission), or fluid friction and inertia as utilized in the fluid coupling and torque converter (found on an automatic transmission).

Overdrive can refer to two different things. An overdrive is a device which was commonly used on rear-wheel drive automobiles to allow the choice of an extra-high overall gear ratio for high speed cruising, thus saving fuel, at the cost of less torque.

It also refers to a combination of gearing inside a transmission or transaxle which results in the output speed being greater than the input speed. In the latter case, "overdrive" does not refer to a physically separate identifiable part/assembly.

c. Difference between rear wheel drive and front wheel drive
If you put a car on a hydraulic lift, raised all four wheels off the ground, turned on the engine, and put it in gear, the rear wheels of rear-wheel drive vehicle would turn, while the front wheels of a front-wheel drive vehicle would turn. In a four-wheel drive vehicle, all four wheels would spin. The terms simply indicate which wheels are connected to the engine via the transmission.

d. Difference between drum brakes and disk brakes, standard brakes and power brakes, and the parking brake
The diagram on the right shows the parts of a drum brake system. The brake is taken apart in this photo showing the brake drum on the left, and the brake shoes on the right. In operation, the shoes fit inside the drum. The drum rotates with the wheel, and the shoes are held stationary. When the brakes are applied, the shoes press against the inside surface of the drum, and the friction produced slows the wheels, stopping them ultimately.

The diagram on the right shows the parts of a disk brake system. Here, the disk (gold) rotates with the wheel, and a stationary pair of calipers (red) squeeze both sides of the disc.

In standard brakes the energy supplied by the operator’s foot in pushing down on the brake pedal is transferred to the brake mechanism on the wheels by various means. A mechanical hookup has been used since the earliest motor vehicles, but hydraulic pressure is used most extensively at the present time. Mechanically operated braking systems are obsolete on today’s automobiles, but these systems may be used for a portion of the braking systems in many vehicles.

Power braking systems are designed to reduce the effort required to depress the brake   pedal when stopping or holding a vehicle stationary. Most power brake systems use the difference in pressure between intake manifold vacuum and atmospheric pressure to develop the additional force required to decrease brake pedal pressure. When a vehicle is powered by a diesel engine, the absence of intake manifold vacuum requires the use of an auxiliary vacuum pump. This type of pump usually is driven by the engine or by an electric motor.

The parking brake usually is operated by an auxiliary foot pedal or hand lever located in the driver compartment. This brake mechanism is designed to keep the vehicle stationary when the operator is not present. It is usually integrated into the disk or drum brake system (which ever is used) and locks in place until released by the operator.

a. Check engine and transmission oil levels.
There are usually two dipsticks in the engine compartment for checking the engine oil and transmission oil levels. Once the dipstick is located, simply pull it out, wipe it clean on a rag or paper towel, reinsert it, pull it out again and check the level. The dipstick will be wet with oil up to the level of the fluid, and fluid levels are marked on the stick itself.

b. Check water/anti-freeze level. Change and flush the cooling system.
The coolant level (also known as antifreeze) can be checked by looking in a plastic reservoir off the dise of the engine. This reservoir is usually mounted on the fender or on the front grill. It has markings on the side and an overflow area. It is also semi-transparent so that you can see the level of the coolant inside.

Flushing the cooling system

 * 1) The first thing you will need to do is make sure the engine is cool. It is very dangerous to open the cooling system on a hot engine, as serious burns can result.  While you're waiting for the engine to cool, get a container that will hold at least two gallons.  You will drain the coolant into this.  Apply the parking brake.
 * 2) Set the vehicles temperature control to Hot. This opens a valve in some vehicles, connecting (or isolating) the car's heater and the cooling system.
 * 3) Open the radiator cap and locate the valve at the bottom of the radiator. If there is no valve, you may have to disconnect the hose at the bottom of the radiator.  Get the catch container ready, open the valve, and maneuver the catch container into position to catch the coolant which should begin flowing as soon as you open the valve.
 * 4) Allow the radiator to drain. This may take a while.  When coolant stops coming out, close the valve again.
 * 5) Fill the radiator with water - not with coolant. Turn on the engine, let it run until the engine's cooling fan turns on.  This means the thermostat has opened and has allowed the coolant to flow into the engine.  Turn off the engine.  Drain the water out using the same steps as outlined above.
 * 6) Add a 50-50 mixture of water and antifreeze to the radiator until it is about an inch from the fill neck. Add more coolant to the reservoir, filling it to the "full" line.  Then - with the radiator cap off - turn the engine on again while monitoring the coolant level.  Add more coolant as the level drops, until it quits dropping.  Replace the radiator cap.
 * 7) Take the waste coolant to a service station for recycling.
 * 8) After driving the vehicle for the first time after flushing the cooling system, let it cool and check the coolant level - both in the reservoir and by removing the radiator cap. Add coolant if it is necessary.

c. Change engine oil and filter.
When an engine is not running, the oil collects in an oil pan or sump at the bottom of the crankcase. There is an oil drain plug normally screwed into a drain hole at the bottom of the oil pan which is accessible from underneath the vehicle. To change the oil in a vehicle's engine, the drain plug is unscrewed to let the oil drain out of the oil pan and into a container. After the used oil drains out, the plug is screwed back into the drain hole. Some drain plugs have a replaceable washer to prevent leakage due to corrosion, rust or worn threads in the drain hole. The removable oil filter can be unscrewed at this time, often with the help of an oil filter removal tool, or in some cases, by hand. Then a new oil filter screwed back in after applying fresh oil to the sealing surface of the new filter. Then new oil is poured in through an otherwise capped opening at the top of the engine. For many cars, 4 to 5 quarts or liters of oil are needed to fill the engine. Take the old motor oil to a service station for recycling. It is illegal to dispose of used motor oil in the trash or dump it into the environment!

d. Change a tire/wheel assembly, following proper safety procedure.

 * 1) Locate the point on the car designed to take the jack. This is usually illustrated in the owner's manual, and is often a point on the chassis a few inches behind the front tire, or a few inches in front of the rear tire.
 * 2) Place chocks around two of the car's tires. If changing a front tire, place the chocks on the two rear tires.  If changing a rear tire, place them on the front tires.  Chocks are brick-sized blocks that prevent the car from rolling.  Indeed, you can use about anything for a chock, so long as it will stand up to the pressure of a car being parked on it, and if it is tall enough to prevent the car from rolling over it.  Bricks, blocks, blocks of wood, or even large rocks can be used as chocks, or you can use store-bought ones.
 * 3) Set the parking brake.
 * 4) Loosen the lug nuts, but do not remove them yet. It is easier to loosen them before jacking up the vehicle because the tires will remain stationary.  Once the vehicle is jacked up, the wheels will easily rotate, making it more difficult to loosen the lug nuts.  It may be necessary to remove the hubcap to get at the lug nuts.  The hubcap usually prys off with a screw driver or with the end of the jack handle.  Be careful not to damage the hubcap.
 * 5) Place the jack beneath the jack point and use it to lift the vehicle. Do not ever lift more than one tire from the ground at a time!  This is a very dangerous thing to do, because it makes it very easy to knock a car off the jacks.
 * 6) Stop lifting the vehicle as soon as the tire is lifted from the ground.
 * 7) Finish removing the lug nuts.
 * 8) Once all the lug nuts have been removed, you may pull the tire/wheel assembly towards yourself and off the wheel mount. Once it's off, you can carefully roll it out of the way and get the new tire (or the same tire since this is likely an exercise, and there is likely nothing wrong with the tire in the first place).
 * 9) Lift the new tire onto the wheelmount, aligning the holes in the wheel with the bolts on the wheel mount. Push the tire into position and quickly put a lug nut or two in place.  Get them all on, and finger-tight first, and then get the lug wrench out and begin tightening the first lugnut.
 * 10) After the first lug nut is tightened, move to the one on the opposite side of the wheel (or as near to opposite as you can get) and tighten it. Continue tightening the other nuts, going to opposite sides of the wheel each time so that they are tightened evenly.  When they are all right, lower the jack.
 * 11) Remove the jack.
 * 12) Go around the lug nuts again, tightening them further. With the car's weight preventing the tires from rotating, you should be able to tighten them a little more (but don't overdo it).
 * 13) Congratulate yourself on a job well done.

e. Lubricate the chassis according to the vehicle service manual.
Lubrication of the chassis is accomplished by using a grease gun. Grease guns have a tube on them through which the grease is forced. At the end of this tube is a fitting that attaches to a grease nipple. The vehicle service manual will show you where to find the grease nipples. First wipe any dirt or foreign material from the grease nipple. Then place the grease gun on the grease nipple and force grease into it. Remove the grease gun and wipe the grease nipple clean so that no dirt accumulates there. Do this to all the grease nipples on the vehicle.

5. How often should the engine oil, transmission oil, and cooling fluid be changed?
The manufacturer specifies how often the oil changes should be made. For example, most people believe that the oil change frequency should be every 3000 miles or every 3 months, whichever comes sooner. This 3000 mile oil change interval has been relentlessly promoted by oil changing companies for decades. It had a scientific basis when engines used non-multi-weight, non-detergent oil. It no longer has any scientific basis, but it is still being promoted by certain entities, most notably the oil change industry in the United States (including car dealerships). Most manufacturers recommend oil change intervals of 6,000 miles or more for modern cars. For convenience, the oil filter is usually also replaced at the time the oil is changed.

Transmission fluid change frequency is specified in the owner's manual, but is most often every 15,000 miles.

How often the coolant should be flushed and changed is also spelled out in the owner's manual. 30,000 miles or three years is typical.

6. Give some pointers on proper care of the vehicle and its finish, both interior and exterior.
The owner's manual has a service schedule in it, telling you how often to change the oil, various filters, and other maintenance items. You also need to check tire inflation and tread wear on a regular basis. If you have ever pedaled a bicycle with low tires, you know that it requires much more effort to propel a vehicle with improperly inflated tires.

Keep your vehicle clean, and wax it at least once per year (in the autumn is best so the car's finish is protected from any road salt). Vacuum the interior as often as you change the oil, as any dirt that stays in the carpet will accelerate carpet wear. Wipe vinyl and leather seats down with an appropriate cleaner and vacuum cloth seats. You should also clean the dashboard and interior door panels regularly.


text:
Electronics/Latches and Flip Flops

Intro
A flip-flop is a circuit which exists in one of two states and so can store information.

A simple flip-flop can be defined in terms of two NAND logic gates. Flip-flops are non linear circuits, meaning the output from one of its gates is fed 'back' to be processed with the input signal. Because flip-flops operate on an input signal mixed with this previous output signal their own outputs are dependent upon their previous state.

A flip flop (F/F) is a device made out of digital gates that uses feedback to store the state (1 or 0) of its input(s). Flip Flops are frequently used to latch input data. Meaning that in a circuit they are fed some binary value and then hold it until the latch is turned off. All flip flops have at least one output labeled Q. Frequently they have a complement, labeled /Q. The 4 basic flip flops are SR, D, Toggle and JK.

A latch is an example of a bistable multivibrator, that is, a device with exactly two stable states. These states are high-output and low-output. A latch has a feedback path, so information can be retained by the device. Therefore latches can be memory devices, and can store one bit of data for as long as the device is powered. As the name suggests, latches are used to "latch onto" information and hold in place. Latches are very similar to flip-flops, but are not synchronous devices, and do not operate on clock edges as flip-flops do.

SR latch
An SR latch (Set/Reset) is an asynchronous device: it works independently of control signals and relies only on the state of the S and R inputs. In the image we can see that an SR flip-flop can be created with two NOR gates that have a cross-feedback loop. SR latches can also be made from NAND gates, but the inputs are swapped and negated. In this case, it is sometimes called an $\overline{SR}$ latch.

When a high is applied to the Set line of an SR latch, the Q output goes high (and $\overline{SR}$ low). The feedback mechanism, however, means that the Q output will remain high, even when the S input goes low again. This is how the latch serves as a memory device. Conversely, a high input on the Reset line will drive the Q output low (and $\overline{Q}$ high), effectively resetting the latch's "memory". When both inputs are low, the latch "latches" – it remains in its previously set or reset state.

When both inputs are high at once, however, there is a problem: it is being told to simultaneously produce a high Q and a low Q. This produces a "race condition" within the circuit – whichever flip flop succeeds in changing first will feedback to the other and assert itself. Ideally, both gates are identical and this is "metastable", and the device will be in an undefined state for an indefinite period. In real life, due to manufacturing methods, one gate will always win, but it's impossible to tell which it will be for a particular device from an assembly line. The state of S = R = 1 is therefore "illegal" and should never be entered.

When the device is powered up, a similar condition occurs, because both outputs, Q and $\overline{Q}$, are low. Again, the device will quickly exit the metastable state due to differences between the two gates, but it's impossible to predict which of Q and $\overline{Q}$ will end up high. To avoid spurious actions, you should always set SR flip-flops to a known initial state before using them – you must not assume that they will initialise to a low state.

In general, RS Flip Flop has a symbol and a truth table as shown
 * {| class=wikitable style="; margin: 1em auto 1em auto"

|- !width=40| S !!width=40| R  |rowspan=5| !width=40| Q !! width=40|$\overline{Q}$ |- | 0 || 0 || colspan=2|Latch |- | 0 || 1 || 0 || 1  |-  | 1 || 0 || 1 || 0  |-  | 1 || 1 || colspan=2 | Metastable
 * }

Gated SR latch
In some situations it may be desirable to dictate when the latch can and cannot latch. The gated SR latch is a simple extension of the SR latch which provides an Enable line which must be driven high before data can be latched. Even though a control line is now required, the SR latch is not synchronous, because the inputs can change the output even in the middle of an enable pulse.

When the Enable input is low, then the outputs from the AND gates must also be low, thus the Q and $\overline{Q}$ outputs remain latched to the previous data. Only when the enable input is high can the state of the latch change, as shown in the truth table. When the enable line is asserted, a gated SR latch is identical in operation to an SR latch.

The Enable line is sometimes a clock signal, but is usually a read or write strobe.

D latch
The D latch (D for "data") or transparent latch is a simple extension of the gated SR latch that removes the possibility of invalid input states.

Since the gated SR latch allows us to latch the output without using the S or R inputs, we can remove one of the inputs by driving both the Set and Reset inputs with a complementary driver: we remove one input and automatically make it the inverse of the remaining input.

The D latch outputs the D input whenever the Enable line is high, otherwise the output is whatever the D input was when the Enable input was last high. This is why it is also known as a transparent latch – when Enable is asserted, the latch is said to be "transparent" – it signals propagate directly through it as if it isn't there.

D latches are often used in I/O ports of integrated circuits and are available as discrete devices, often multiply packaged. An example is the 74HC75, part of the 7400 series of ICs, containing four separate D latches.

SR Flip Flops

The fundamental latch is the simple SR flip-flop , where S and R stand for set and reset respectively. It can be constructed from a pair of cross-coupled NOR logic gates. The stored bit is present on the output marked Q.

Normally, in storage mode, the S and R inputs are both low, and feedback maintains the Q and Q outputs in a constant state, with Q the complement of Q. If S (Set) is pulsed high while R is held low, then the Q output is forced high, and stays high even after S returns low; similarly, if R (Reset) is pulsed high while S is held low, then the Q output is forced low, and stays low even after R returns low.

('X' denotes a Don't care condition; meaning the signal is irrelevant)

D Flip Flops

The Q output always takes on the state of the D input at the moment of a rising clock edge. (or falling edge if the clock input is active low) It is called the D flip-flop for this reason, since the output takes the value of the D input or Data input, and Delays it by one clock count. The D flip-flop can be interpreted as a primitive memory cell, zero-order hold, or delay line.

Truth table:

 * {|class="wikitable" style="text-align:center"

('X' denotes a Don't care condition, meaning the signal is irrelevant)
 * Clock||D||Q||Qprev
 * Rising edge||0||0||X
 * Rising edge||1||1||X
 * Non-Rising||X||Qprev||
 * }
 * Non-Rising||X||Qprev||
 * }
 * }

These flip flops are very useful, as they form the basis for shift registers, which are an essential part of many electronic devices. The advantage of the D flip-flop over the D-type latch is that it "captures" the signal at the moment the clock goes high, and subsequent changes of the data line do not influence Q until the next rising clock edge. An exception is that some flip-flops have a 'reset' signal input, which will reset Q (to zero), and may be either asynchronous or synchronous with the clock.

The above circuit shifts the contents of the register to the right, one bit position on each active transition of the clock. The input X is shifted into the leftmost bit position.

Toggle Flip Flops
If the T input is high, the T flip-flop changes state ("toggles") whenever the clock input is strobed. If the T input is low, the flip-flop holds the previous value. This behavior is described by the characteristic equation:

 * $$Q_{next} = T \oplus Q$$ (or, without benefit of the XOR operator, the equivalent: $$Q_{next} = T\overline{Q} + \overline{T}Q$$)

and can be described in a truth table:

When T is held high, the toggle flip-flop divides the clock frequency by two; that is, if clock frequency is 4 MHz, the output frequency obtained from the flip-flop will be 2 MHz. This 'divide by' feature has application in various types of digital counters. A T flip-flop can also be built using a JK flip-flop (J & K pins are connected together and act as T) or D flip-flop (T input and Qprevious is connected to the D input through an XOR gate).

JK Flip Flops

The JK flip-flop augments the behavior of the SR flip-flop (J=Set, K=Reset) by interpreting the S = R = 1 condition as a "flip" or toggle command. Specifically, the combination J = 1, K = 0 is a command to set the flip-flop; the combination J = 0, K = 1 is a command to reset the flip-flop; and the combination J = K = 1 is a command to toggle the flip-flop, i.e., change its output to the logical complement of its current value. Setting J = K = 0 does NOT result in a D flip-flop, but rather, will hold the current state. To synthesize a D flip-flop, simply set K equal to the complement of J. The JK flip-flop is therefore a universal flip-flop, because it can be configured to work as an SR flip-flop, a D flip-flop, or a T flip-flop. NOTE: The flip flop is positive edge triggered (Clock Pulse) as seen in the timing diagram.

The characteristic equation of the JK flip-flop is:

$$Q_{next} = J\overline Q + \overline KQ$$

and the corresponding truth table is:

title: Electronics/Latches and Flip Flops


text:
Wikijunior:Kings and Queens of England/More Anglo-Saxons

Edward the Confessor (1042-1066)
Edward the Confessor was born in Islip, Oxfordshire around the year 1004. He was the penultimate Anglo-Saxon King of England and the last of the House of Wessex, ruling from 1042 until his death in 1066. His reign marked the continuing disintegration of royal power in England, which was replaced by more power going to the great territorial earls.

Edward, along with his brothers, was taken to Normandy by his mother Emma, the sister of the Duke of Normandy, Richard II, in 1013 to escape the Danish invasion of England. In his quarter-century of Norman exile, Edward developed an intense personal piety and gained a familiarity with Normandy and its leaders that was to influence his later rule.

In 1036 he returned to England with his brother Alfred to try to displace Harold Harefoot as king, but this failed, Alfred was caught and brutally killed by Earl Godwin with a red hot poker. Luckily, Edward escaped back to Normandy. In 1041 he was invited back by the Anglo-Saxon lay and ecclesiastical nobility to be co-ruler with Harthacanute, and when Harthacanute died in June 1042, Edward ascended the throne. He was crowned at Winchester Cathedral on 3 April 1043.

Edward's Reign
Edward's reign was marked by peace and prosperity, but to rule effectively Edward had to come to terms with three powerful nobles. The first of these was Godwin, Earl of Wessex, who was firmly in control of Wessex which had formerly been the heart of the Anglo-Saxon monarchy. Next there was Leofric, Earl of Mercia, and in the north there was Siward, Earl of Northumbria.

Edward favoured Normans, however, and this frustrated both Saxon and Danish nobles and fueled the growth of anti-Norman opinion led by Godwin, who had become the king's father-in-law in 1045. The breaking point came when Edward appointed the then Bishop of London, the Norman Robert Jumièges, as Archbishop of Canterbury rather than Godwin's preferred choice. There was a bloody riot at Dover between the townsfolk and Edward's kinsman, Eustace, Count of Boulogne. After Godwin refused to punish the townsfolk, Leofric and Siward backed King Edward and Godwin and his family were all exiled in September 1051. Edward's queen, Eadgyth, who was also Godwin's daughter, was sent to a nunnery at Wherwell. Godwin returned with an army a year later forcing the king to restore his title and send away his Norman advisors. Godwin died in 1053 and a Norman, Ralph the Timid, was given Herefordshire but his son Harold accumulated even greater territories for the Godwins and later became Edward's successor.

Marriage and Heirs
Edward married Godwin's daughter, Eadyth of Wessex, on 23 January 1045. They had no children. His nearest heir would have been a nephew, also called Edward, who was born in England but spent most of his life in Hungary. He had returned from exile in 1056 and died not long after, in February the following year. So Edward made his great nephew Edgar Atheling his heir, but Edgar did not have much of a following among the nobles and this led to Harold Godwinson being declared king

Death and Legacy
Edward died in January 1066. The cult that grew up around him in the mediaeval period under the later Plantagenet kings has had a lasting impact on English history. Edward had founded Westminster Abbey, where he was buried, sometime between 1045 and 1050, and it was consecrated on 28 December 1065. When Henry II came to the throne in 1154, he united the Saxon and Norman royal lines. To reinforce his legitimacy, the cult of King Edward the Confessor was promoted. Westminster Abbey was redesigned to contain a shrine to Edward, which remains there to this day. After much lobbying, Edward was made a saint by Pope Alexander III in 1161. At the time when Edward was made a saint, there were two types: martyrs and confessors. Martyrs were people who died in the service of the Lord, and confessors were people who died natural deaths. Since Edward died a natural death, he was styled Edward the Confessor.

The Roman Catholic Church now regards Edward the Confessor as the patron saint of kings, difficult marriages and separated spouses. After the reign of Henry II, Edward was considered the patron saint of England until 1348 when he was replaced in this role by Saint George. He remains the patron saint of the Royal Family.

Harold Godwinson (1066)
Harold Godwinson or Harold II of England was born around the year 1022 in Wessex. He ruled from 5 January to 14 October 1066, when he was killed at the Battle of Hastings. Harold's father was Godwin, the powerful Earl of Wessex. Godwin married twice and it was his second marriage that produced Harold, Tostig and Edith.

Harold was made Earl of East Anglia in 1045, and then accompanied his father, Godwin, into exile in 1051. A year later he helped Godwin regain his position. When Godwin died in 1053, Harold inherited the earldom of Wessex, which made him the second most powerful figure in England after the king. In 1058 Harold also became Earl of Hereford, and he replaced his late father as the focus of opposition to growing Norman influence in England under the restored Saxon monarchy of Edward the Confessor. In 1062 and 1063 Harold then successfully fought a series of campaigns against the ruler of Gwynedd, Gruffydd ap Llywelyn, who had conquered all of Wales. About 1064, Harold married Aldith, daughter of the Earl of Mercia, and widow of Gruffydd ap Llywelyn. By Harold, Aldith had two sons, Harold and Ulf. Harold also had several illegitimate children by his mistress, Eadgyth.

In 1064, Harold was shipwrecked in Normandy and was turned over to the court of Duke William. William considered himself to be the successor of the childless Edward the Confessor, and got Harold to swear an oath to support William as the future king of England. In 1065 Harold supported a Northumbrian rebellion against taxes levied by his brother Tostig and replaced him with Morcar, the Earl of Northumbria. This strengthened his acceptability as Edward's successor, but divided his own family. Tostig went into alliance with King Harald Hardrada of Norway. In January 1066, upon Edward's death, Harold was proclaimed king by the Witenagemot who, under Anglo-Saxon law held the ultimate authority to convey kingship.

Harold's Reign
Harold's position as king, though, was much disputed and the country was invaded, first by Harald Hardrada of Norway and then by William, Duke of Normandy. Harold offered his brother, Tostig, a third of the kingdom, and Tostig asked what Harold would offer the king of Norway. "Six feet of ground or as much more as he needs, as he is taller than most men," was Harold's response according to Henry of Huntingdon. Invading what is now Yorkshire in September, 1066, Harald Hardrada and Tostig defeated the English earls, Edwin of Mercia and Morcar of Northumbria, at the Battle of Fulford near York on 20 September. But they were in turn defeated and killed by Harold's army five days later at the Battle of Stamford Bridge. Harold now forced his army to march 240 miles to meet William, who had landed about 7,000 men in Sussex, on 28 September. Harold established his army near Hastings, and on 14 October the two armies clashed at the Battle of Hastings, near the present town of Battle. Harold was killed and his forces routed. According to tradition, Harold was killed by an arrow in the eye, but the victim depicted in the Bayeux Tapestry is anonymous. Whether he did, indeed, die in this manner, or was killed by the sword, is unknown.

Edgar Atheling (1066)
Edgar Atheling was born around the year 1051. Born in Hungary, he was also known as Edgar the Outlaw. The Anglo-Saxon name Atheling means "man of noble blood, chief, prince" and was used to designate the sons of the king. Edgar was the only son of Edward the Exile, heir to the English throne and grandson of King Edmund II Ironside. Upon his father's death in 1057, Edgar was nominated as heir apparent by the King Edward the Confessor. Edgar was brought up at Edward's court, together with his sisters Margaret and Christina. However he was too young at the time of the king's death in January 1066 to defend the country against invasion and his election as king after Harold's death was no more than a symbolic token of defiance against the invading Norman forces. After Harold II's death he was proclaimed, but never crowned, King of England. Edgar relied largely for his support upon Archbishop Stigand and upon Earls Edwin of Mercia and Morcar of Northumbria and, when this weakened within a matter of days of the witan that proclaimed him king, Edgar was forced to submit to William at Berkhamstead in either late November or early December 1066.

William treated Edgar well. Seeing political advantage, he kept him in his custody and eventually took him back to his court in Normandy. Edgar joined in the rebellion of the earls Edwin and Morcar in 1068 and, defeated, he fled to the court of Malcolm III of Scotland. The next year Malcolm married Edgar's sister Margaret, and agreed to support Edgar in his attempt to claim the English crown. In exchange, Edgar married Malcolm's sister, another Margaret. Edgar now made common cause with Sweyn Estridson, the king of Denmark and nephew of Canute, who believed he was the rightful king of England. Their combined forces invaded England in 1069, and they captured York. William marched on the north, devastating the land as he went. He paid the Danes to leave, and Edgar fled back to Scotland. He remained there till 1072 when William forced Malcolm to accept a peace treaty that also required Edgar to be exiled. Edgar eventually made his peace with William in 1074, but he never fully gave up his dreams of regaining the throne of England. He supported Robert, Duke of Normandy, against William II in 1091 and again found himself seeking refuge in Scotland. He also supported his nephew, Edgar, in gaining the Scottish throne, overthrowing Donald III.

Around 1098 he went to Constantinople, where he may have joined the Varangian Guard of the Byzantine Empire. Later that year he was given a fleet by Emperor Alexius I so he could help in the First Crusade, and Edgar brought reinforcements to the crusaders at the Siege of Antioch. He was taken prisoner during battle in 1106 whilst fighting for Duke Robert against King Henry I of England. He returned to England where Henry pardoned him, and he retired to his country estate in Hertfordshire. His niece Edith (renamed Matilda) had married Henry I in 1100. Edgar is believed to have returned to the Kingdom of Scotland late in life, perhaps around the year 1120, and was still alive in 1125, but may have died soon after, in his early seventies.


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Talk:Introduction to Indonesian Philosophy

Well, I fully agree with the idea. That's a good idea. What should I do then to merge it? Should I leave this book unfinished in the process of merging or what? Please advise me.203.123.254.39 10:57, 10 March 2006 (UTC)


text:
User:FHidayat

Hello, guys. I am a contributor to Wikipedia, Wikibooks, and Wikiquote. Please see my profile in Wikipedia

title: User:FHidayat


text:
User:Dresdnhope

I am working on the Visual Basic .Net Wikibook. I consider myself a beginning programmer, so I would appreciate anyone who's willing to jump in and help.

Click below to go to the Visual Basic .Net Wikibook

Visual Basic .NET

title: User:Dresdnhope


text:
Talk:Quenya

Syllabary
Is there are list of words that could be used as either a syllabary or a glossary (non-copyrighted... if that is possible)? That seems like a key feature that is missing from this textbook right now. --Rob Horning 16:03, 10 March 2006 (UTC)

 * Rob, there's little complete evidence of corresponding canon quenya vocabulary. The most complete that I have heard is a document from the old/primitive quenya (spelt 'qenya', but pronounced the same).

 * I don't know about legal status on these documents:

 * http://www.uib.no/people/hnohf/qlindex1.htm
 * http://www.uib.no/people/hnohf/qlindex2.htm

 * But we could definitely link to them, and see what the author feels about making derivative works of them (reproducing them, in a revised presentation, on this site). —Auk 00:52, 11 November 2006 (UTC)

Wikiversity course
There is now a Wikiversity course being developed for Quenya. See Quenya. Jade Knight 18:39, 26 October 2006 (UTC)

Stress markings
Which syllable to stress is one of the harder things to get right when learning a language; it's more an innate 'feel' than calculating based upon known rules. I suggest we (in addition to providing the rules) emphasize the stressed syllables of words, especially when modifying with prefixes and suffixes and in the lower chapters. This would ease the student (it would help me a lot) into a more natural feel to the rhythm of the language.

Comments on the style in which to do this? (Bold, italics, underline, capitals?)

—Auk 21:57, 10 November 2006 (UTC)

I think this will make these pages more complicated than needed.

It might however be useful on the paradigms page. I don't know how it would best be indicated as underlines are already use to indicate irregularities.

—User:Dirk_math 12 November 2006

A user of the Elfling mailing list has sent a link to this WikiBook. It generated so far criticism from one of the authors cited as the source of this WikiBook, Thorsten Renk. You can read it at Elfling message http://groups.yahoo.com/group/elfling/message/33860

I do not agree with his vision that "in this situation, the Wikipedia concept is bound to fail", but it surely can be much improved. The Book, as it is, may mislead the reader into thinking that Quenya is a fully developed and completely usable language, when in fact Tolkien apparently never had such intentions. For example, the scope of this WikiBook could be shifted from a "how do I learn Quenya" type of book (there are two well-written ones already) to a "how did Tolkien develop his ideas on Quenya through the course of his lifetime." I can find Quenya courses in a snap on Google, but I can't say the same about comparative analysis of the various stages of the Quenya development.

If this shift doesn't happen, at least change the name of the WikiBook to "Neo-Quenya," which is more accurate.

-User:Jaroszewski 23 February 2007

Book name change
Should this book maybe rather be called Neo-Quenya since it's on that topic, rather than Quenya. --Swift (talk) 01:52, 26 October 2008 (UTC)

 * Yes_check.svg Done. – Adrignola discuss 21:03, 3 February 2011 (UTC)

Disclaimer stating this book is on Neo-Quenya was added back onto the main page of the book. Thus it seems contrary to not have the book named Neo-Quenya. – Adrignola discuss 00:03, 6 February 2011 (UTC)

 * The disclaimer doesn't mean that in any way. It is simply a reminder that it is about a version of the language as it is now used and not as Tolkien has left it in 1973. I rewrote it to make that clearer.
 * And would it have been so difficult to ask about the change before rushing in? Someone now renamed the main page back to Quenya, but this is even worse as the book is now inconsistent as all the other pages and the category are still called Neo-Quenya. Dirk math (discuss • contribs) 17:46, 6 February 2011 (UTC)

I have found this book useful - up to a point. It presents some information that is not included in other prominent books on Quenya including the page on "special verbs", however it is generally lacking in citations to Tolkein's work and any discussion of controversy or period-relevance of words (are they 'Qenya'? are they 'LotR era Quenya'? or late Quenya developments?  At least a footnote would be good, for canon words a citation back to the Tolkein work where they appear and for inferred words an explanation of the rationale behind the inference.  Certainly the addition of references would give it better academic credence and separate it from the dross "elvish" courses that take whatever they can from Quenya, Sindarin, Telerin etc. Ecthelion 22:45, 20 March 2013 (UTC)

Pages in limbo
There are a whole bunch of pages under the name Special:PrefixIndex/Neo-Quenya, which somehow or other ended up over there while the book is over here. I'm not sure what's going on with them, but it's a mess that needs to be cleaned up. There's even a |book category for the other name, even though there's no book there. --Pi zero (discuss • contribs) 02:15, 1 November 2016 (UTC)
 * I've moved all the pages to be under the current book main page. --Pi zero (discuss • contribs) 03:33, 5 December 2017 (UTC)
 * Deleted redirects, except left main page redirect for now. --Pi zero (discuss • contribs) 17:44, 5 December 2017 (UTC)

Tengwar fonts
The tengwar font page seems not to be accessible anymore. Does anybody know another source for this encoding? Or, one could consider to switch to the proposed Unicode encoding which has some fonts available. --Mmh (discuss • contribs) 13:31, 4 January 2023 (UTC)

 * Although I generally favor the use of the proposed Unicode encoding (I use it myself), changing this entire book would be a lot of work, and could introduce significant errors. I think it would be easier to edit the link, http://web.comhem.se/alatius/fonts/annatar.html  (a dead link), to point to a different source.  I found the referenced Annatar font at https://www.dafont.com/tengwar-annatar.font.   I tested it and it worked, although I had to deactivate my ad blocker on the page. From looking at the source for the page, I see that it supports the following fonts: Tengwar Annatar, Tengwar Eldamar, Tengwar Noldor, Tengwar Parmaite, Tengwar Formal, Tengwar Elfica, Tengwar Sindarin, Tengwar Quenya, and Tengwar Gothika.  Many of these can be found here: https://fontsgeek.com/search/?q=Tengwar
 * I would recommend perhaps some intermediary page to explain the Tengwar fonts issue.  Nomme Ectawa (discuss • contribs) 04:21, 13 April 2024 (UTC)

title: Talk:Quenya


text:
Organic Chemistry/Authors

If you wish to be formally listed as an author of the Organic Chemistry Wikibook, please sign your name below.

According to the United States Code for registering a copyrighted work, you must include your nationality (what country you claim citizenship in) and the country you are currently residing in, if different. It is also suggested by the U.S. Copyright office to include the year you were born, for identification purposes. They also ask for the year of death, and if you know of a Wikibookian who has passed away, this would also be useful. How exactly we are going to collect this information for users and contributors of this Wikibooks is totally unknown, and is going to be an interesting little ride. Please add comments in the discussion page if you have any reservations about giving this information out. This is moving into new territory here, so we don't know exactly what is going to be required or if new policies should or ought to be developed.

Keep in mind, this information is needed only if you want to be credited formally as the author of this Wikibook and have your information correctly cited in any formal registration procedure for this Wikibook. Efforts to get this information put into the general user record of MediaWiki have met with huge resistance even on a voluntary basis, so this is the only forum for you to even put this sort of information out to the public. This information may also be needed for enforcement of copyright laws in the unfortunate situation where somebody copies this Wikibook contrary to the terms of the GFDL. An attempt to contact you would then be done to see if you would be willing to enforce your copyright for this Wikibook.

Anonymous authors include those who made edits without logging in as a user. While edits of this nature are appreciated, there is no way we can give attribution to any specific person unless they have created an account here.

Authors
And many anonymous Wikibook contributors.
 * 1) Karl Wick Citizen of the United States of America, and living there
 * The initiator of this project is Karl Wick, who is finishing up his premed science courses at the Cleveland State University in Cleveland, Ohio. At the time of this writing (7/15/03) I have been the sole contributor but as time goes on it will become a group project "of the people" as many contribute and improve it by bits and pieces.
 * 1) Justin Johnson Citizen of the United States of America, residing therein, born 1975
 * Justin Johnson(JSJohnson) is a pre-medical undergraduate student at Indiana University Purdue University Indianapolis. He first read this book in the summer of 2005, and began contributing to it in the spring of 2006.
 * 1) David Rose
 * David Rose (Ghostal) is a chemical engineering undergraduate at Michigan Technological University. He began adding to this book in October, 2004.
 * Patrick Holder (Lineweaver) is a PhD Graduate Student working for Matt Francis at UC-Berkeley in the Department of Chemistry. He began adding to this book in December, 2005.
 * 1) Zachary T. Tackett, Zach is a student at Marshall University majoring in bio-organic chemistry.
 * 2) Igoroisha
 * Goh Liang Song (User:Gohliangsong) Citizen of the Republic of Singapore. He graduated from the National University of Singapore, majoring in Chemistry. He began adding to this book in August, 2006.
 * 1) Pete Davis Citizen of the United States of America. I joined this project in November 2006. There are few of us working on it at the moment. Feel free to join in.
 * 2) Ewen McLaughlin UK Citizen, living in Wales. I started adding bits here in February 2006. I'm a teacher, so I suppose I might be more help with how to present information than with the information itself.

Many thanks to Jimbo Wales for paying for the bandwidth and for the many other ways he has been a great support to this project at every step.

كيمياء عضوية/مساعدة للمحررين

title: Organic Chemistry/Authors


text:
Visual Basic .NET/The Visual Studio Integrated Development Environment

An integrated development environment (IDE), also known as integrated design environment and integrated debugging environment, is a type of computer software that assists computer programmers to develop software. In the case of Visual Basic .NET, that IDE is Visual Studio.

IDE Contents
The Visual Studio IDE consists of several sections, or tools, that the developer uses while programming. As you view the IDE for a new project you generally have three sections in view:
 * The Toolbox on the left
 * The Solution Explorer on the right
 * The Code / Design view in the middle

Toolbox
The Toolbox is a palette of developer objects, or controls, that are placed on forms or web pages, and then code is added to allow the user to interact with them. An example would be TextBox, Button and ListBox controls. With these three controls added to a Windows Form object the developer could write code that would take text. We can easy to access those things while using IDE.

Solution Explorer
This is a section that is used to view and modify the contents of the project. A Visual Studio Windows Application Project will generally have a Form object with a code page, references to System components and possibly other modules with special code that is used by the application.

Properties Windows
The properties window shows all the control (like Textbox) properties to be changed at design time. Most of these properties can be also changed with code at run time, but basically most properties change the way the control is displayed on your application.

Object Browser
By pressing F2 or selecting it into the View menu, it's possible to explore all the available objects of the libraries (types, functions...).

Review
The Visual Studio IDE is a complex and exciting work space for developers, providing many enhancements and upgrades from the days of Visual Basic 4.0 or the introduction of C++. This section only serves as a mere introduction to this multi-functional interface.

Visual Basic .NET/Visual_Studio


text:
Organic Chemistry/Print version

= Contents = If you save this file to your computer, you can click on these links to go to the appropriate section.
 * Copyright · Authors · Forward

 * 1) Unit 1: Foundational Concepts of Organic Chemistry
 * Ch 1: History of Organic Chemistry · Ch 2: Atomic Structure · Ch 3: Electronegativity · Ch 4: Bonding · Ch 5: Electron Dot Structures & Formal Charge · Ch 6: CResonance · Ch 7: Acids and Bases
 * 1) Unit 2: Alkanes and Cycloalkanes
 * Ch 1: Methane and Carbon Chains · Ch 2: Properties of Alkanes · Ch 3: Drawing Alkanes · Ch 4: Branched Alkanes · Ch 5: Constitutional Isomers · Ch 6: Naming Alkanes · Ch 7: Cycloalkanes · Ch 8: Newman Projections and Conformers · Ch 9: Conformations · Ch 10: Stereoisomers and Chirality
 * 1) Unit 3: Stereochemistry
 * Ch 1: Chirality · Ch 2: Optical Activity · Ch 3: Enantiomers · Ch 4: Meso Compounds · Ch 5: Diastereomers · Ch 6: Configurations · Ch 7: R-S Notational System
 * 1) Unit 4: Haloalkanes
 * 2) Unit 5: Alcohols
 * 3) Unit 6: Amine
 * 4) Unit 7: Alkenes
 * Ch 1: Alkene Properties · Ch 2: Naming Alkenes · Ch 3: Cycloalkenes · Ch 4: The pi bond · Ch 5: Stability of Double Bonds · Ch 6: Alkene Reactions
 * 1) Unit 8: Alkynes
 * Ch 1: The Triple Carbon-Carbon Bond · Ch 2: Alkyne Properties · Ch 3: Naming Alkynes · Ch 4: Cycloalkynes · Ch 5: Alkyne Reactions
 * 1) Unit 9: Dienes
 * Ch 1: Kinds of Dienes · Ch 2: Conjugation · Ch 3: Diene Properties and eactions
 * 1) Unit 10: Aromatics
 * Ch 1: Aromatics in history · Ch 2.1: Benzene structure · Ch 2.2: Benzene Properties · Ch 4.1: Overview of Electrophilic Aromatic Substitution Reactions · Ch 4.5: Friedel-Crafts Alkylation · Ch 4.6: Friedel-Crafts Acylation · Ch 10: Aromatic reactions
 * 1) Unit 11: Ketones and Aldehydes
 * 2) Unit 12: Carboxylic Acids
 * 3) Unit 13: Carboxylic Acid Derivatives
 * 4) Unit 14: Analytical Techniques
 * Ch 1: Elemental Analysis · Ch 2: Chromatography · Ch 3: Spectroscopy
 * 1) Unit 15: Organometallics

 * 1) Appendix A: Introduction to Reactions
 * 1: How to Write Organic Reactions · 2: Overview of Addition, Elimination, Substitution and Rearrangement Reactions · 3: Polar and Radical Reactions · 4: Redox Reactions · 5: Functional Groups in Reactions · 6: Drawing Reactions · 7: Rates and Equilibria · 8: Gibbs Free Energy · 9: Bond Dissociation Energy · 10: Energy Diagrams · 11: Transition States · 12: Carbocations · 13: Electrophilic Additions · 14: Zaitsev's Rule · 15: Hydroboration/Oxidation · 16: Radicals · 17: Rearrangement Reactions · 18: Pericyclic Reactions · 19: Diels-Alder Reaction · 20: Epoxide
 * 1) Appendix B: Index of Reactions
 * 2) Appendix C: Introduction to Functional Groups
 * What is a Functional Group?
 * 1) Other Appendices
 * Glossary · Short Periodic Table · External Links

= Authors = The authors of this book are:

= Foreword =

= Unit 1: Foundational concepts of organic chemistry =

= History of organic chemistry =

= Atomic structure =

= Electronegativity =

= Bonding =

= Electron dot structures & formal charge =

= Resonance =

= Acids and bases =

= Unit 2: Alkanes and cycloalkanes =

= Alkanes =

= Methane and carbon chains =

= Properties of alkanes =

= Drawing alkanes =

Branched alkanes
= Constitutional isomers =

= Naming alkanes =

= Cycloalkanes =

= Newman projections and conformers =

= Conformations =

= Stereoisomers and chirality =

= Unit 3: Stereochemistry =

= Chirality =

= Optical activity =

= Enantiomers =

= Meso compounds =

= Diastereomers =

= Configurations =

= R-S notational system =

= Unit 4: Haloalkanes =

= Unit 5: Alcohols =

= Unit 6: Amine =

= Unit 7: Alkenes =

= Unit 8: Alkynes =

= The triple carbon-carbon bond =

= Alkyne properties =

= Naming alkynes =

= Cycloalkynes =

= Alkyne reactions =

= Unit 9: Dienes =

= Kinds of dienes =

= Conjugation =

= Diene properties and reactions =

= Unit 10: Aromatics =

= Aromatics in history =

= Benzene structure =

= Benzene properties =

= Overview of electrophilic aromatic substitution reactions =

= Friedel-Crafts alkylation =

= Friedel-Crafts acylation =

= Aromatic reactions =

= Unit 11: Ketones and aldehydes =

= Unit 12: Carboxylic acids =

= Unit 13: Carboxylic acid derivatives =

= Unit 14: Analytical techniques =

= Elemental analysis =

= Chromatography =

= Spectroscopy =

= Unit 15: Organometallics =

= Appendix A: Introduction to reactions =

= How to write organic reactions =

= Overview of addition, elimination, substitution and rearrangement reactions =

= Polar and radical reactions =

= Redox reactions =

= Functional groups in reactions =

= Drawing reactions =

= Rates and equilibria =

= Gibbs free energy =

= Bond dissociation energy =

= Energy diagrams =

= Transition states =

= Carbocations =

= Electrophilic additions =

= Zaitsev's rule =

= Oxidation =

= Radicals =

= Rearrangement reactions =

= Pericyclic reactions =

= Diels-Alder reaction =

= Epoxide =

= Appendix B: Index of reactions =

= Appendix C: Introduction to functional groups =

= Overview of Functional Groups =

= Other appendices =

= Glossary =

= Short periodic table =

= External links =

title: Organic Chemistry/Print version


text:
Talk:Piano/Chords (and pop examples)

Notation
We need notation, or at least we need to figure out how to correctly structure the book. There should be an extended introduction in basics that at least introduces notation. When I learn a new language, I always observe the written part first. We need a functional tutorial, that works step-by-step, not something to just explain what's happening. I'd go through old method books and figure out how they started off, and then embellish it with learned knowledge. I'll work on this later, but it's 3 am now. --Zen 10:30, 15 July 2006 (UTC)

Images
Please, if you can replace the images with the correct ones, do so. Masahiko 16:53, 10 March 2006 (UTC)

--What's wrong with them?

I think they are confusing for the beginners. They need to see from the beginning that the most important things in music are patterns. Chords, scales, extremely confusingly super-kablooey counterpoint :) Only chords in their rootpositions first, we can put the inversions in later. Otherwise the pictures are good. Masahiko 20:38, 7 June 2006 (UTC)

title: Talk:Piano/Chords (and pop examples)


text:
Arimaa/Elephant Blockade

An elephant mobility advantage is most often procured by threats which keep the enemy elephant on defense. Sometimes, however, an elephant can be physically blocked. If an elephant is surrounded and can't simply push its way out, that elephant is blockaded.

The corners can be dangerous places for elephants. Gold might willingly expose a small piece to capture in c3 if such a capture would require the silver elephant to end the turn on c2. Early on, players discovered that some bots could be lured into a blockade this way. Once the elephant found itself surrounded, it would look for a quick escape, and thus could be tempted further by an empty c1; the blockade could then become stronger, as it is easier to smother a piece against the edge.

In, Silver took the bait and was strategically lost by the ninth turn. Due to the b1, d1, and c2 phalanxes, the silver elephant has no move at all. With the only functional elephant, Gold is in firm control. Silver could try to free her elephant, but Gold could ward off or capture any silver piece which approached the blockade. To keep it intact, Gold must continue to occupy c3, and thus should restrict most home captures to f3.

Rotation
Most elephant blockades are not as lopsided as the one above, which was only possible because the bot thought nothing of where it placed its elephant. An elephant even one square away from the edge will at least have a potentially quicker escape path.

Having his elephant stuck on g7 would be no problem for Gold if Silver kept this exact blockade in place. Until Silver moves a blockading piece, the strongest free piece is the gold camel.

Silver can, however, rotate pieces out of the blockade. If Silver now slides his camel and three rabbits with mh6s rh7s rh8s rg8e, those rabbits will block the gold elephant from h7, and the camel can move west. Although g8 is left empty, it is not an escape path; the gold elephant must stay on g7 to avoid being completely smothered against the edge.

Silver should try to form a phalanx to replace her elephant, which could then dominate the board. Gold must race to free his elephant; a gold piece, maybe the camel, must reach some place where it can pull away a blockading piece, thus allowing the gold elephant to push its way to freedom. Silver could make such a rescue harder by playing a move such as ce7s ce8s rd8s. If a path does open for the gold elephant to move west or south, it must do so immediately. Even if the gold elephant escapes, the rescuing piece may be lost, but that is better than having one's own elephant stuck and the enemy elephant free. Gold must throw caution in the wind to break this blockade.

For the blockade to remain intact without the silver elephant, a silver phalanx must extend to g5, so the blockade would use more pieces and be more breakable than one which stuck the elephant against the edge. Still, a free silver elephant could easily neutralize the gold camel, and the silver camel could stop any other gold piece. In the, the silver camel went to g5, rounding out this phalanx while continuing to protect the h-file.

Were the gold elephant on g6 and the silver elephant on g5, it would be a different story; a silver phalanx extending to g4 and f5 could be quite vulnerable, so elephant rotation might not be feasible for Silver. If rotation is not an option, the strength of a blockade depends on the free pieces. The opponent might attack on the other wing, or might try to break the blockade from the center; the blockader might then give up the blockade but capture a piece.

In any blockade position, a blunder by either side could be huge. Both sides must keep track of possible escape paths and even possible captures.

Cost
As with a frame, an elephant blockade may require too much material when one's forces are already depleted. The silver elephant appeared hopelessly stuck in, but Gold had to move pieces west to defend goal.

Elephants in middle
With ee4nn rc6e, Silver to move can block the gold elephant from the south and west; d7 would be blocked by a phalanx, and e6 would be blocked by the silver elephant, which would also defend f6 so that Gold couldn't capture anything there. Surrounded on three sides, the gold elephant couldn't flip any piece. The gold elephant might hope to escape via the east, but Silver could stop that with solid tactics, beginning with a fourth step of rh8s, which would allow Silver to block the gold elephant on both the g- and h-files.

With no clear escape path, a surrounded elephant should probably stay as close to the center as possible; this blockade would not be strong unless the silver elephant could rotate out, which would be much more likely if the gold elephant went east and thus marginalized itself further. Gold might instead create a western threat to force the silver elephant to abandon the blockade.

Friendly rabbit blockade
Unable to step backward, a rabbit blocked in the other three directions cannot be moved by its owner. When advanced rabbits of the same color are side-by-side, they might all get stuck in place, forming a wall which could severely limit the movement of other friendly pieces.

After move 48s of, well-placed silver pieces combined with five advanced gold rabbits to blockade the gold elephant, camel, and dog. In the east, four more gold pieces couldn't move at all. The gold horses were stuck in the south. For the next eight turns, Silver's elephant and eastern horse did all the work, pushing Gold toward complete immobilization. To avoid this, Gold sacrificed his elephant.

Such a blockade could be risky on a depleted board. In, the stuck silver rabbits threatened goal, and Gold walked a tight rope to keep them blocked while also defending in the east.

Blockading the gold elephant on g6 would often require the silver elephant to remain on g5, since a silver phalanx extending to g4 and f5 could be highly vulnerable. In, however, such a phalanx was formed mostly by stuck gold pieces. Gold might have hoped to get a piece onto e6 or f7 and then move his elephant through the trap, but Silver can now easily prevent that. Two advanced gold rabbits have allowed Silver to completely immobilize three strong gold pieces.

With a gold rabbit on a5 and the silver elephant on b5 in, the gold elephant was stuck in the northwest. If Silver can get an additional gold rabbit onto b5, the silver elephant could rotate out and dominate the board.

Partial blockades
Even if an elephant can't be fully smothered, it might be marginalized for several turns. With Silver's elephant boxed in, his horse-by-camel hostage is useless; the strongest free piece is the gold camel. The silver elephant could eventually escape, perhaps through the c6 trap, but the gold camel could make a capture in the meantime.

The Center
A semi-centralized elephant can sometimes be blockaded by a phalanx on a central square. Such a phalanx will occupy three of the four central squares; a strong piece on the fourth central square might protect and reinforce the phalanx. Silver's central blockade is strong, not only because of his camel but also because of his advanced elephant and horse. Even if Gold got his elephant onto d5 via Hc4w rd4w cd5s Ec5e, Silver could then capture the c3 rabbit by dislodging the c2 cat; Silver would then have a strong trap attack and goal threat.

This strategy requires great caution; if a central dividing wall does not hold, the pieces likely can't all retreat. This blockade worked because of the attack on c3, which the silver elephant soon rotated out of.

Swarm
Even in its own home territory, an elephant is not always safe from a blockade; a swarm can sometimes blockade an elephant next to its home trap. In, Silver exploited the bot's susceptibility to elephant blockades.

The frozen gold cat has become part of the blockade holding in the gold elephant. Gold might try to change that with ha3s Eb3w rb4s Ca4e, but an elephant usually can't escape a blockade via the edge of the board; in this case, the c4 horse could then push the gold cat back to a4, immobilizing both the cat and elephant, as b3 would now be blocked by a silver phalanx.

As things stand, the gold elephant might eventually escape to the center via the second rank, but then Silver could make captures in c3, and the advanced silver rabbits would become strong goal threats. Silver's swarm has put the gold elephant in an impossible situation; a home hostage-holder must be wary of such a swarm.

title: Arimaa/Elephant Blockade


text:
Talk:FHSST Physics/Electrostatics/Electrostatic Force

I can only see this in Worked Example 60 Coulomb's Law II

Step 3 :

Calculate the electrostatic force using Coulomb's Law:

Failed to parse (unknown function\rmC): \begin{matrix}F_E&=&k\frac{Q_1 Q_2}{r^2}=k\frac{e\cdot e}{1\AA^2}\\&=&(8.99\times10^{9}\rm N\cdot m^2/C^2)\frac{(-1.60\times10^{-19}{\rm C})(-1.60\times10^{-19}\rmC)}{(10^{-10}\rm m)^2}\\&=&2.30\times10^{-8}\rm N\end{matrix}

Hence the magnitude of the electrostatic force between the electrons is 2.30\times10^{-8}\rm N. (Note that the electrons carry like charge and from this we know the force must be repulsive. Another way to see this is that the force is positive and thus repulsive.)

Step 4 :

Calculate the gravitational force: Failed to parse (unknown function\cdotm): \begin{matrix}F_E&=&G\frac{m_1m_2}{r^2}=G\frac{m_e\cdot m_e}{(1\AA)^2}\\&=&(6.67\times10^{-11}{\rm N\cdotm^2/kg^2})\frac{(9.11\times10^{-31}{\rm C})(9.11\times10^{-31}{\rm kg})}{(10^{-10}{\rm m})^2}\\&=&5.54\times10^{-51}{\rm N}\end{matrix}

The magnitude of the gravitational force between the electrons is 5.54\times10^{-51}\rm N


text:
Chinese (Mandarin)/Traditional/Lesson 1

=Lesson 1: 你好！=

It is appropriate to start off the introduction to Chinese with the common greeting: 你好. Below is a dialogue between two people meeting each other for the first time.

Vocabulary
Note: Visit this lesson's Stroke Order subpage to see images and animations detailing how to write the following characters. Audio files of the words are linked from the pīnyīn when available. Problems listening? See media help.

Basic Sentences
1. 我叫艾美.
 * Wǒ jiào Àiměi.
 * I'm called Amy.

Sentences using shì [是]
1. 我是中國人.
 * Wǒ shì Zhōngguórén.
 * I am a Chinese person.

2. 她是金妮.
 * Tā shì Jīnní.
 * She is Ginny.

3. 她們是英國人.
 * Tāmen shì Yīngguórén.
 * They are English.

1. 他不是東尼.
 * Tā bú shì Dōngní.
 * He is not Tony.

2. 我不是美國人.
 * Wǒ bú shì Měiguórén.
 * I am not American.

The question particle ma [嗎]
The declarative example sentence in #1 is transformed into an interrogative in #2.

1. 她是金妮.
 * Tā shì Jīnní.
 * She is Ginny.

2. 她是金妮嗎？
 * Tā shì Jīnní ma?
 * Is she Ginny?

The question particle ne [呢]
1. 我叫東尼，你呢？
 * Wǒ jiào Dōngní, nǐ ne?
 * I'm called Tony. How about you?

2. 艾美是中國人，他呢？
 * Àiměi shì Zhōngguórén, tā ne?
 * Amy is Chinese. How about him?

Question words
1. 他們是哪國人？
 * Tāmen shì nǎ guó rén?
 * What country are they from?

2. 誰是美國人？
 * Shéi shì Měiguórén?
 * Who is American?

3. 她是誰？
 * Tā shì shéi?
 * Who is she?

title: Chinese (Mandarin)/Traditional/Lesson 1