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Inverted pendulum

An inverted pendulum is a pendulum that has its center of mass above its pivot point. It is unstable and falls over without additional help. It can be suspended stably in this inverted position by using a control system to monitor the angle of the pole and move the pivot point horizontally back under the center of mass when it starts to fall over, keeping it balanced. The inverted pendulum is a classic problem in dynamics and control theory and is used as a benchmark for testing control strategies. It is often implemented with the pivot point mounted on a cart that can move horizontally under control of an electronic servo system as shown in the photo; this is called a cart and pole apparatus. Most applications limit the pendulum to 1 degree of freedom by affixing the pole to an axis of rotation. Whereas a normal pendulum is stable when hanging downward, an inverted pendulum is inherently unstable, and must be actively balanced in order to remain upright; this can be done either by applying a torque at the pivot point, by moving the pivot point horizontally as part of a feedback system, changing the rate of rotation of a mass mounted on the pendulum on an axis parallel to the pivot axis and thereby generating a net torque on the pendulum, or by oscillating the pivot point vertically. A simple demonstration of moving the pivot point in a feedback system is achieved by balancing an upturned broomstick on the end of one's finger.

A second type of inverted pendulum is a tiltmeter for tall structures, which consists of a wire anchored to the bottom of the foundation and attached to a float in a pool of oil at the top of the structure that has devices for measuring movement of the neutral position of the float away from its original position.

Overview
A pendulum with its bob hanging directly below the support pivot is at a stable equilibrium point, where it remains motionless because there is no torque on the pendulum. If displaced from this position, it experiences a restoring torque that returns it toward the equilibrium position. A pendulum with its bob in an inverted position, supported on a rigid rod directly above the pivot, 180° from its stable equilibrium position, is at an unstable equilibrium point. At this point again there is no torque on the pendulum, but the slightest displacement away from this position causes a gravitation torque on the pendulum that accelerates it away from equilibrium, causing it to fall over. In order to stabilize a pendulum in this inverted position, a feedback control system can be used, which monitors the pendulum's angle and moves the position of the pivot point sideways when the pendulum starts to fall over, to keep it balanced. The inverted pendulum is a classic problem in dynamics and control theory and is widely used as a benchmark for testing control algorithms (PID controllers, state-space representation, neural networks, fuzzy control, genetic algorithms, etc.). Variations on this problem include multiple links, allowing the motion of the cart to be commanded while maintaining the pendulum, and balancing the cart-pendulum system on a see-saw. The inverted pendulum is related to rocket or missile guidance, where the center of gravity is located behind the center of drag causing aerodynamic instability. The understanding of a similar problem can be shown by simple robotics in the form of a balancing cart. Balancing an upturned broomstick on the end of one's finger is a simple demonstration, and the problem is solved by self-balancing personal transporters such as the Segway PT, the self-balancing hoverboard and the self-balancing unicycle.

Another way that an inverted pendulum may be stabilized, without any feedback or control mechanism, is by oscillating the pivot rapidly up and down. This is called Kapitza's pendulum. If the oscillation is sufficiently strong (in terms of its acceleration and amplitude) then the inverted pendulum can recover from perturbations in a strikingly counterintuitive manner. If the driving point moves in simple harmonic motion, the pendulum's motion is described by the Mathieu equation.

Equations of motion
The equations of motion of inverted pendulums are dependent on what constraints are placed on the motion of the pendulum. Inverted pendulums can be created in various configurations resulting in a number of Equations of Motion describing the behavior of the pendulum.

Stationary pivot point
In a configuration where the pivot point of the pendulum is fixed in space, the equation of motion is similar to that for an uninverted pendulum. The equation of motion below assumes no friction or any other resistance to movement, a rigid massless rod, and the restriction to 2-dimensional movement.

 * $$\ddot \theta - {g \over \ell} \sin \theta = 0$$

Where $$\ddot \theta $$ is the angular acceleration of the pendulum, $$g $$ is the standard gravity on the surface of the Earth, $$\ell$$ is the length of the pendulum, and $$\theta$$ is the angular displacement measured from the equilibrium position.

When $$\ddot \theta $$ added to both sides, it has the same sign as the angular acceleration term:

 * $$\ddot \theta = {g \over \ell} \sin \theta$$

Thus, the inverted pendulum accelerates away from the vertical unstable equilibrium in the direction initially displaced, and the acceleration is inversely proportional to the length. Tall pendulums fall more slowly than short ones.

Derivation using torque and moment of inertia:

The pendulum is assumed to consist of a point mass, of mass $$m $$, affixed to the end of a massless rigid rod, of length $$\ell$$, attached to a pivot point at the end opposite the point mass.

The net torque of the system must equal the moment of inertia times the angular acceleration:
 * $$\boldsymbol{\tau}_{\mathrm{net}}=I \ddot \theta$$

The torque due to gravity providing the net torque:
 * $$\boldsymbol{\tau}_{\mathrm{net}}= m g \ell \sin \theta\,\!$$

Where $$ \theta\ $$ is the angle measured from the inverted equilibrium position.

The resulting equation:
 * $$ I \ddot \theta= m g \ell \sin \theta\,\!$$

The moment of inertia for a point mass:
 * $$I = m R^2$$

In the case of the inverted pendulum the radius is the length of the rod, $$ \ell $$.

Substituting in $$I = m \ell ^2$$
 * $$ m \ell ^2 \ddot \theta= m g \ell \sin \theta\,\!$$

Mass and $$\ell^2$$ is divided from each side resulting in:
 * $$\ddot \theta = {g \over \ell} \sin \theta$$

Inverted pendulum on a cart
An inverted pendulum on a cart consists of a mass $$ m $$ at the top of a pole of length $$ \ell $$ pivoted on a horizontally moving base as shown in the adjacent image. The cart is restricted to linear motion and is subject to forces resulting in or hindering motion.

Essentials of stabilization
The essentials of stabilizing the inverted pendulum can be summarized qualitatively in three steps.

1.	If the tilt angle $$ \theta $$ is to the right, the cart must accelerate to the right and vice versa.

2.	The position of the cart $$ x $$ relative to track center is stabilized by slightly modulating the null angle (the angle error that the control system tries to null) by the position of the cart, that is, null angle $$ = \theta + k x $$ where $$ k $$ is small. This makes the pole want to lean slightly toward track center and stabilize at track center where the tilt angle is exactly vertical. Any offset in the tilt sensor or track slope that would otherwise cause instability translates into a stable position offset. A further added offset gives position control.

3.	A normal pendulum subject to a moving pivot point such as a load lifted by a crane, has a peaked response at the pendulum radian frequency of $$ \omega_p = \sqrt {g/\ell} $$. To prevent uncontrolled swinging, the frequency spectrum of the pivot motion should be suppressed near $$ \omega_p $$. The inverted pendulum requires the same suppression filter to achieve stability.

As a consequence of the null angle modulation strategy, the position feedback is positive, that is, a sudden command to move right produces an initial cart motion to the left followed by a move right to rebalance the pendulum. The interaction of the pendulum instability and the positive position feedback instability to produce a stable system is a feature that makes the mathematical analysis an interesting and challenging problem.

From Lagrange's equations
The equations of motion can be derived using Lagrange's equations. We refer to the drawing to the right where $$\theta(t)$$ is the angle of the pendulum of length $$l$$ with respect to the vertical direction and the acting forces are gravity and an external force F in the x-direction. Define $$x(t)$$ to be the position of the cart.

The kinetic energy $$T$$ of the system is:

T = \frac{1}{2} M v_1^2 + \frac{1}{2} m v_2^2, $$

where $$v_1$$ is the velocity of the cart and $$v_2$$ is the velocity of the point mass $$m$$. $$v_1$$ and $$v_2$$ can be expressed in terms of x and $$\theta$$ by writing the velocity as the first derivative of the position;

v_1^2=\dot x^2, $$

v_2^2=\left({\frac{\rm d}{{\rm d}t}}{\left(x- \ell\sin\theta\right)}\right)^2 + \left({\frac{\rm d}{{\rm d}t}}{\left( \ell\cos\theta \right)}\right)^2. $$ Simplifying the expression for $$v_2$$ leads to:

v_2^2= \dot x^2 -2 \ell \dot x \dot \theta\cos \theta + \ell^2\dot \theta^2. $$

The kinetic energy is now given by:

T = \frac{1}{2} \left(M+m \right ) \dot x^2 -m \ell \dot x \dot\theta\cos\theta + \frac{1}{2} m \ell^2 \dot \theta^2. $$

The generalized coordinates of the system are $$\theta$$ and $$x$$, each has a generalized force. On the $$x$$ axis, the generalized force $$Q_x$$ can be calculated through its virtual work

Q_x\delta x=F \delta x,\quad Q_x=F, $$

on the $$\theta$$ axis, the generalized force $$Q_\theta$$ can be also calculated through its virtual work

Q_\theta\delta\theta=mgl\sin\theta \delta \theta,\quad Q_\theta=mgl\sin\theta. $$

According to the Lagrange's equations, the equations of motion are:

\frac{\mathrm{d}}{\mathrm{d}t}{\partial{T}\over \partial{\dot x}} - {\partial{T}\over \partial x} = F, $$

\frac{\mathrm{d}}{\mathrm{d}t}{\partial{T}\over \partial{\dot \theta}} - {\partial{T}\over \partial \theta} = mgl\sin\theta, $$ substituting $$T$$ in these equations and simplifying leads to the equations that describe the motion of the inverted pendulum:

\left ( M + m \right ) \ddot x - m \ell \ddot \theta \cos \theta + m \ell \dot \theta^2 \sin \theta = F, $$

\ell \ddot \theta - g \sin \theta = \ddot x \cos \theta. $$

These equations are nonlinear, but since the goal of a control system would be to keep the pendulum upright the equations can be linearized around $$\theta \approx 0$$.

From Euler-Lagrange equations
The generalized forces can be both written as potential energy $$V_x$$ and $$V_\theta$$,

According to the D'Alembert's principle, generalized forces and potential energy are connected:

 * $$Q_j = \frac{\mathrm{d}}{\mathrm{d}t}\frac{\partial V}{\partial \dot{q}_j} - \frac{\partial V}{\partial q_j} \,,$$

However, under certain circumstances, the potential energy is not accessible, only generalized forces are available.

After getting the Lagrangian $$L=T-V$$, we can also use Euler–Lagrange equation to solve for equations of motion:

 * $$\frac {\partial L}{\partial x} - \frac{\mathrm{d}}{\mathrm{d}t} \left ( \frac {\partial L}{\partial \dot{x}} \right ) = 0$$,
 * $$\frac {\partial L}{\partial \theta} - \frac{\mathrm{d}}{\mathrm{d}t} \left ( \frac {\partial L}{\partial \dot{\theta}} \right ) = 0$$.

The only difference is whether to incorporate the generalized forces into the potential energy $$V_j$$ or write them explicitly as $$Q_j$$ on the right side, they all lead to the same equations in the final.

From Newton's second law
Oftentimes it is beneficial to use Newton's second law instead of Lagrange's equations because Newton's equations give the reaction forces at the joint between the pendulum and the cart. These equations give rise to two equations for each body; one in the x-direction and the other in the y-direction. The equations of motion of the cart are shown below where the LHS is the sum of the forces on the body and the RHS is the acceleration.

F-R_x = M \ddot x $$

F_N - R_y - M g = 0 $$

In the equations above $$R_x$$ and $$R_y$$ are reaction forces at the joint. $$F_N$$ is the normal force applied to the cart. This second equation depends only on the vertical reaction force, thus the equation can be used to solve for the normal force. The first equation can be used to solve for the horizontal reaction force. In order to complete the equations of motion, the acceleration of the point mass attached to the pendulum must be computed. The position of the point mass can be given in inertial coordinates as

\vec r_P = (x-\ell \sin \theta) \hat x_I + \ell \cos \theta \hat y_I $$

Taking two derivatives yields the acceleration vector in the inertial reference frame.

\vec a_{P/I} = (\ddot x + \ell \dot \theta^2 \sin \theta - \ell \ddot \theta \cos \theta ) \hat x_I + (-\ell \dot \theta^2 \cos \theta  - \ell \ddot \theta \sin \theta) \hat y_I $$

Then, using Newton's second law, two equations can be written in the x-direction and the y-direction. Note that the reaction forces are positive as applied to the pendulum and negative when applied to the cart. This is due to Newton's Third Law.

R_x = m(\ddot x + \ell \dot \theta^2 \sin \theta - \ell \ddot \theta \cos \theta ) $$

R_y - m g = m (-\ell \dot \theta^2 \cos \theta - \ell \ddot \theta \sin \theta) $$

The first equation allows yet another way to compute the horizontal reaction force in the event the applied force $$F$$ is not known. The second equation can be used to solve for the vertical reaction force. The first equation of motion is derived by substituting $$F-R_x = M \ddot x$$ into $$R_x = m(\ddot x + \ell \dot \theta^2 \sin \theta - \ell \ddot \theta \cos \theta )$$, which yields

\left (M+m \right) \ddot x - m \ell \ddot \theta \cos \theta  + m \ell \dot \theta^2 \sin \theta  = F $$

By inspection this equation is identical to the result from Lagrange's Method. In order to obtain the second equation, the pendulum equation of motion must be dotted with a unit vector that runs perpendicular to the pendulum at all times and is typically noted as the x-coordinate of the body frame. In inertial coordinates this vector can be written using a simple 2-D coordinate transformation

\hat x_B = \cos \theta \hat x_I + \sin \theta \hat y_I $$

The pendulum equation of motion written in vector form is $$\sum \vec F = m \vec a_{P/I}$$. Dotting $$\hat x_B$$ with both sides yields the following on the LHS (note that a transpose is the same as a dot product)

(\hat x_B)^T\sum \vec F = (\hat x_B)^T (R_x \hat x_I + R_y \hat y_I - m g \hat y_I) = (\hat x_B)^T(R_p \hat y_B - m g \hat y_I) = -m g \sin \theta $$

In the above equation the relationship between body frame components of the reaction forces and inertial frame components of reaction forces is used. The assumption that the bar connecting the point mass to the cart is massless implies that this bar cannot transfer any load perpendicular to the bar. Thus, the inertial frame components of the reaction forces can be written simply as $$R_p \hat y_B$$, which signifies that the bar can transfer loads only along the axis of the bar itself. This gives rise to another equation that can be used to solve for the tension in the rod itself:

R_p = \sqrt{ R_x^2 + R_y^2} $$

The RHS of the equation is computed similarly by dotting $$\hat x_B$$ with the acceleration of the pendulum. The result (after some simplification) is shown below.

m(\hat x_B)^T(\vec a_{P/I}) = m(\ddot x \cos \theta - \ell \ddot \theta) $$

Combining the LHS with the RHS and dividing through by m yields

\ell \ddot \theta - g \sin \theta = \ddot x \cos \theta $$

which again is identical to the result of Lagrange's method. The benefit of using Newton's method is that all reaction forces are revealed to ensure that nothing is damaged.

Variants
Achieving stability of an inverted pendulum has become a common engineering challenge for researchers. There are different variations of the inverted pendulum on a cart ranging from a rod on a cart to a multiple segmented inverted pendulum on a cart. Another variation places the inverted pendulum's rod or segmented rod on the end of a rotating assembly. In both, (the cart and rotating system) the inverted pendulum can fall only in a plane. The inverted pendulums in these projects can either be required to maintain balance only after an equilibrium position is achieved, or can achieve equilibrium by itself. Another platform is a two-wheeled balancing inverted pendulum. The two wheeled platform has the ability to spin on the spot offering a great deal of maneuverability. Yet another variation balances on a single point. A spinning top, a unicycle, or an inverted pendulum atop a spherical ball all balance on a single point.

Kapitza's pendulum
An inverted pendulum in which the pivot is oscillated rapidly up and down can be stable in the inverted position. This is called Kapitza's pendulum, after Russian physicist Pyotr Kapitza who first analysed it. The equation of motion for a pendulum connected to a massless, oscillating base is derived the same way as with the pendulum on the cart. The position of the point mass is now given by:
 * $$\left( -\ell \sin \theta, y + \ell \cos \theta   \right)$$

and the velocity is found by taking the first derivative of the position:
 * $$v^2=\dot y^2-2 \ell \dot y \dot \theta \sin \theta + \ell^2\dot \theta ^2.$$[[Image:Inverted pendulum oscillatory base.svg|thumb|right|500px|Plots for the inverted pendulum on an oscillatory base. The first plot shows the response of the pendulum on a slow oscillation, the second the response on a fast oscillation]]

The Lagrangian for this system can be written as:

L = \frac{1 }{2} m \left ( \dot y^2-2 \ell \dot y \dot \theta \sin \theta + \ell^2\dot \theta ^2   \right) - m g \left( y + \ell \cos \theta  \right ) $$ and the equation of motion follows from:

{\mathrm{d} \over \mathrm{d}t}{\partial{L}\over \partial{\dot \theta}} - {\partial{L}\over \partial \theta} = 0 $$ resulting in:

\ell \ddot \theta - \ddot y \sin \theta = g \sin \theta. $$ If y represents a simple harmonic motion, $$y = A \sin \omega t$$, the following differential equation is:

\ddot \theta - {g \over \ell} \sin \theta = -{A \over \ell} \omega^2 \sin \omega t \sin \theta. $$

This equation does not have elementary closed-form solutions, but can be explored in a variety of ways. It is closely approximated by the Mathieu equation, for instance, when the amplitude of oscillations are small. Analyses show that the pendulum stays upright for fast oscillations. The first plot shows that when $$y$$ is a slow oscillation, the pendulum quickly falls over when disturbed from the upright position. The angle $$\theta$$ exceeds 90° after a short time, which means the pendulum has fallen on the ground. If $$y$$ is a fast oscillation the pendulum can be kept stable around the vertical position. The second plot shows that when disturbed from the vertical position, the pendulum now starts an oscillation around the vertical position ($$\theta = 0$$). The deviation from the vertical position stays small, and the pendulum doesn't fall over.

Examples
Arguably the most prevalent example of a stabilized inverted pendulum is a human being. A person standing upright acts as an inverted pendulum with their feet as the pivot, and without constant small muscular adjustments would fall over. The human nervous system contains an unconscious feedback control system, the sense of balance or righting reflex, that uses proprioceptive input from the eyes, muscles and joints, and orientation input from the vestibular system consisting of the three semicircular canals in the inner ear, and two otolith organs, to make continual small adjustments to the skeletal muscles to keep us standing upright. Walking, running, or balancing on one leg puts additional demands on this system. Certain diseases and alcohol or drug intoxication can interfere with this reflex, causing dizziness and disequilibration, an inability to stand upright. A field sobriety test used by police to test drivers for the influence of alcohol or drugs, tests this reflex for impairment.

Some simple examples include balancing brooms or meter sticks by hand. The inverted pendulum has been employed in various devices and trying to balance an inverted pendulum presents a unique engineering problem for researchers. The inverted pendulum was a central component in the design of several early seismometers due to its inherent instability resulting in a measurable response to any disturbance.

The inverted pendulum model has been used in some recent personal transporters, such as the two-wheeled self-balancing scooters and single-wheeled electric unicycles. These devices are kinematically unstable and use an electronic feedback servo system to keep them upright.

Swinging a pendulum on a cart into its inverted pendulum state is considered a traditional optimal control toy problem/benchmark.

title: Inverted pendulum


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Cindy Crawford

Cynthia Ann Crawford (born February 20, 1966) is an American model. During the 1980s and 1990s, she was among the most popular supermodels and a ubiquitous presence on magazine covers and runways, as well as fashion campaigns. She subsequently expanded into acting and business ventures.

Early life
Crawford was born in DeKalb, Illinois, on February 20, 1966, the daughter of Daniel Kenneth Crawford and Jennifer Sue Crawford-Moluf (née Walker). She has two sisters, Chris and Danielle, and a brother, Jeffery, who died of childhood leukemia at age 3.

On social media, she has stated that her family had been in the United States for generations and that her ancestry was mostly German, English, and French. She is a descendant of English Puritan settler Thomas Trowbridge, who helped establish the Congregational Church in New Haven. She was raised in the Congregationalist faith and found it “incredible” that religious values “trickled down" to her family. According to official census records, Crawford’s paternal great-grandfather David Crawford was of Scottish ancestry from Ulster, Northern Ireland who settled in Wisconsin. Appearing in an episode of Who Do You Think You Are? in 2013, she discovered that her ancestors included European nobility and that she was descended from Charlemagne.

In her sophomore year at high school, she received a call from a local clothing store regarding modeling work, only to discover it was a prank by two of her classmates. However, the following year, another store hired a number of high school girls, including Crawford, to work for them (including a fashion shoot). In her junior year, local photographer Roger Legel, whose duties included photographing a different college girl to be that week's coed in the DeKalb Nite Weekly, asked to take her picture for the publication; the result was Crawford's first cover. The photo and positive feedback she received were enough to convince her to take up modeling. Initially, she worked with a small agency, which was sold to Elite Model Management shortly after she signed. In 1983, she entered Elite's Look of the Year contest at 17 and made the national finals.

Crawford graduated from DeKalb High School in 1984 as valedictorian. She earned an academic scholarship to study chemical engineering at Northwestern University, which she attended for only one quarter before dropping out to pursue a full-time modeling career. After working for photographer Victor Skrebneski in Chicago, she moved to New York City in 1986 and signed with the Elite New York modeling agency.

Career
In 1987, Crawford appeared in the opening credits of the Michael J. Fox film The Secret of My Success. Three years later, she was featured alongside top models Christy Turlington, Linda Evangelista, Tatjana Patitz and Naomi Campbell on the cover of the January 1990 edition of British Vogue. Crawford and the other four models subsequently appeared in the video for George Michael's hit "Freedom! '90" later that year. Subsequently, Crawford played the lost love of Jon Bon Jovi in the 1994 video for his version of "Please Come Home For Christmas", "John Taylor" in the 2011 video for Duran Duran's "Girl Panic" (featuring supermodels as the band, including Naomi Campbell as Simon Le Bon), and Headmistress in the 2015 video for Taylor Swift's "Bad Blood" as part of a cast including Jessica Alba, Selena Gomez, and fellow models Lily Aldridge, Cara Delevingne, Gigi Hadid, Martha Hunt and Karlie Kloss. She was frequently featured on the cover of multiple fashion and lifestyle magazines, including Vogue, W, People, Harper's Bazaar, Elle, Cosmopolitan, and Allure. A partial count in 1998 totalled over 500 appearances. Crawford has walked the runway shows for Chanel, Versace, Dolce & Gabbana, Christian Dior, Calvin Klein, Ralph Lauren, Roberto Cavalli, Michael Kors, Thierry Mugler, Todd Oldham, DKNY, and Valentino. Crawford also appeared in many fashion campaigns during her career, including those for Versace, Calvin Klein, Escada, David Yurman, Oscar De La Renta, Balmain, Hermes, Ellen Tracy, Valentino, Bally, Liz Claiborne, Hervé Leger, Halston, Anne Klein, Isaac Mizrahi, Blumarine, Guess, Ink, Gap, and Revlon. She has also worked for Omega, Maybelline, Clairol, Pepsi, and Chilean retail stores Ripley (partner of Macy's).

In July 1988, she posed nude for Playboy magazine in a shoot by photographer Herb Ritts. In October 1998, Crawford returned to the pages of Playboy for a second nude pictorial, again taken by Ritts. She was ranked number 5 on Playboy's list of the 100 sexiest stars of the 20th century. A 1997 Shape magazine survey of 4,000 picked her as the second (after Demi Moore) most beautiful woman in the world. In 2002, Crawford was named one of the 50 most beautiful people by People magazine. In her forties, she claimed No. 26 in the 2006 Hot 100 issue of Maxim magazine. She was named No. 3 on VH1's 40 Hottest Hotties of the 90s and was named one of the "100 Hottest Women of All-Time" by Men's Health.

The red Versace dress she wore to the 63rd Academy Awards in 1991 had a major influence on fashion, and many copies and fakes of the dress were produced. In 1992, Crawford—through GoodTimes Home Video and her company Crawdaddy Productions—made an exercise video with Radu Teodorescu named Cindy Crawford: Shape Your Body; although criticised by some for being unsafe, it was hugely successful and led to two equally lucrative followups, Cindy Crawford: The Next Challenge in 1993 (again with Radu) and Cindy Crawford: A New Dimension in 2000; the latter, made with fitness expert Kathy Kaehler and produced not long after Crawford gave birth to her first child, was aimed at new mothers getting back into shape. In 2001, Crawford also made a shorter fitness video aimed at children, Mini-Muscles with Cindy Crawford and the Fit-wits, an animated production featuring the voices of Crawford (who also appears at the beginning in live action), Radu and Kobe Bryant.

The inaugural issue of George, a short lived political magazine in the 1990s, featured Crawford dressed like George Washington on the cover. In 2005, the American Society of Magazine Editors listed it as the 22nd best magazine cover of the last 40 years.

Crawford has also been on TV and in films. From 1989 to 1995, Crawford was host and executive producer of MTV's House of Style. In the early 1990s, Crawford starred in the Pepsi and Pepsi Stuff advertising. In 1992, she appeared in Pepsi's Super Bowl commercial, aired during Super Bowl XXVI. In 2016, Pepsi released a remake of the commercial, also featuring Crawford. In 1995, Crawford broke into movies as the female lead in the movie Fair Game. Her performance was panned by critics—Leonard Maltin commented "In her acting debut, supermodel Crawford makes a good jogger." The film was also a financial failure, with expenses of $50 million and $11 million takings at the box office. In 2001, she costarred as part of an ensemble cast in The Simian Line. Again the film was not successful or critically acclaimed, but Crawford's acting was not criticized. She has had many lesser roles guest starring on TV and as supporting roles, often playing herself. For example, in 2000, she was one of the celebrities (along with Victoria Silvstedt, Anna Falchi and Megan Gale) playing themselves in the Italian comedy Body Guards – Guardie del corpo. In the 1990s, Carol Shaw, her make-up artist, named a lipstick color after Crawford as a part of the Lorac Cosmetics lip-wear line.

In the late 1990s, she made a number of appearances in magician David Copperfield's stage shows, standing in for her fellow supermodel Claudia Schiffer as Copperfield's guest assistant. During these appearances, she took part in a number of different illusions including being levitated, guillotined, and sawn in half in Copperfield's Clearly Impossible illusion. On a number of occasions, she joined Copperfield and Schiffer in a performance of the Double Sawing illusion in which both women were sawn in half and then reassembled with their lower halves swapped.

After modeling
Crawford quit full-time modeling in 2000 and now appears only occasionally in fashion magazines. In 2005, Crawford created a line of beauty products with Jean-Louis Sebagh called Meaningful Beauty for Guthy-Renker. Crawford has stated that she regularly receives certain cosmetic procedures, including Botox and vitamin injections. She first saw a plastic surgeon at the age of 29.

In 2005, Crawford launched a new line of furniture under the "Cindy Crawford Home Collection" name. The collection is manufactured by HM Richards Inc. She assisted in the creation of the line by consulting on the features, colors, or styles that fit the needs of families or reflected her own tastes. She also has a furniture line with Rooms to Go, Raymour & Flanigan and launched a home goods line with J. C. Penney in late 2009.

In 2009, Crawford was one of many celebrities to be photographed by Deborah Anderson for the coffee table book Room 23, produced by philanthropist Diana Jenkins. In addition to appearing in the book, Crawford was the cover model and wrote the dedication. Becoming, a book about Crawford's life and career co-written by Crawford and Katherine O'Leary, was published in September 2015.

Crawford appeared on the US version of Lipsync Battle reenacting her performance in the bathtub from the George Michael music for "Freedom! '90", performed by actor Zachary Quinto.

Crawford and her daughter Kaia appeared together on the cover of the April 2016 issue of Vogue Paris. In 2016, she became a spokesperson for Acqua Minerale San Benedetto in Italy. In September 2017, Crawford, along with models Claudia Schiffer, Naomi Campbell, Helena Christensen and Carla Bruni, closed the Versace spring/summer 2018 fashion show, which was an homage to the late Gianni Versace.

In January 2019, Crawford, along with her husband Rande Gerber, Michael Meldman, Jeff Shell, and Jay Sures announced they would purchase the Hollywood deli, Nate 'n Al, to keep its doors open after three generations of family ownership.

Crawford was featured in an upcoming four-part Apple TV+ docuseries titled The Super Models, which premiered on September 20, 2023. The series also featured Naomi Campbell, Christy Turlington, and Linda Evangelista and was directed by Roger Ross Williams and Larissa Bills.

Personal life
Crawford was married to actor Richard Gere from 1991 until their divorce in 1995. She married businessman and former model Rande Gerber on May 29, 1998. They have two children, son Presley Walker Gerber (born July 2, 1999) and daughter Kaia Jordan Gerber (born September 3, 2001), the latter of whom has had a successful modeling career.

In August 2021, the couple sold their home in Trousdale Estates, Beverly Hills, for a reported $13.5 million.

Style and appearance
Crawford is 5 ft tall with brown hair and eyes. Her measurements are 34–25.5–36. Her trademark is a mole (or "beauty mark") above her upper lip. She is so closely associated with this physical feature that she appeared in an Australian advertising campaign for flavoured milk featuring a TV commercial wherein she "licked off" her own mole. Her resemblance to model Gia Carangi led her to being known as "Baby Gia".

Advocacy and charity work
When Crawford was 10 years old, her three-year-old brother Jeff—whom she continues to praise as "the fourth most influential person in [her] life"—died of leukemia. Since becoming a model, Crawford has made childhood leukemia a focal point of her charity work, donating proceeds of her calendars to medical research. Crawford has been a long-time supporter of the pediatric oncology program at the University of Wisconsin–Madison, where Jeff was treated, stating that she believes he received the best care possible. She is also an honorary board member of the Multiple Myeloma Research Foundation.

In 2007, she became an official supporter of the Ronald McDonald House Charities and is a member of their celebrity board, called the Friends of RMHC. Crawford is on the honorary committee of the California Wildlife Center.

In 2021, Cindy Crawford recreated her iconic Pepsi ad with photographer David Yarrow to help raise funds for the American family Children's Hospital in Madison, Wisconsin where her brother, Jeff, was treated for leukemia.

Political endorsements
In 2008, Crawford endorsed Barack Obama for President of the United States. Despite reports, Crawford denied endorsing Mitt Romney for the 2012 election.

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

title: Cindy Crawford


text: Wikipedia:Developer

title: Wikipedia:Developer


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Talk:Text adventure

There's too much crossover and duplication here between Adventure game, interactive fiction and text adventure. I suggest some king of merger would be in order. Mintguy 20:23 11 Jul 2003 (UTC)

 * There is not usually any distinction made between interactive fiction and text adventure - some people prefer one term, and others prefer the other. So I think those two articles should be merged. (In theory, interactive fiction ought to have a much broader meaning, but in practice it doesn't. The current interactive fiction article discusses only text adventures.) Adventure game is much more general, and needs to be kept separate. --Zundark 16:08 16 Jul 2003 (UTC)

 * I propose pretty much deleting this article and redirecting it to Interactive Fiction. I don't think there is anything here that isn't covered there. 2toise 16:36, 4 Oct 2003 (UTC)

title: Talk:Text adventure


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Tidal resonance

In oceanography, a tidal resonance occurs when the tide excites one of the resonant modes of the ocean. The effect is most striking when a continental shelf is about a quarter wavelength wide. Then an incident tidal wave can be reinforced by reflections between the coast and the shelf edge, the result producing a much higher tidal range at the coast.

Famous examples of this effect are found in the Bay of Fundy, where the world's highest tides are reportedly found, and in the Bristol Channel. Less well known is Leaf Bay, part of Ungava Bay near the entrance of Hudson Strait (Canada), which has tides similar to those of the Bay of Fundy. Other resonant regions with large tides include the Patagonian Shelf and on the continental shelf of northwest Australia.

Most of the resonant regions are also responsible for large fractions of the total amount of tidal energy dissipated in the oceans. Satellite altimeter data shows that the M2 tide dissipates approximately 2.5 TW, of which 261 GW is lost in the Hudson Bay complex, 208 GW on the European Shelves (including the Bristol Channel), 158 GW on the North-west Australian Shelf, 149 GW in the Yellow Sea and 112 GW on the Patagonian Shelf.

Scale of the resonances
The speed of long waves in the ocean is given, to a good approximation, by $$\scriptstyle\sqrt{g h}$$, where g is the acceleration of gravity and h is the depth of the ocean. For a typical continental shelf with a depth of 100 m, the speed is approximately 30 m/s. So if the tidal period is 12 hours, a quarter wavelength shelf will have a width of about 300 km.

With a narrower shelf, there is still a resonance but it is mismatched to the frequency of the tides and so has less effect on tidal amplitudes. However the effect is still enough to partly explain why tides along a coast lying behind a continental shelf are often higher than at offshore islands in the deep ocean (one of the additional partial explanations being Green's law). Resonances also generate strong tidal currents and it is the turbulence caused by the currents which is responsible for the large amount of tidal energy dissipated in such regions.

In the deep ocean, where the depth is typically 4000 m, the speed of long waves increases to approximately 200 m/s. The difference in speed, when compared to the shelf, is responsible for reflections at the continental shelf edge. Away from resonance this can reduce tidal energy moving onto the shelf. However near a resonant frequency the phase relationship, between the waves on the shelf and in the deep ocean, can have the effect of drawing energy onto the shelf.

The increased speed of long waves in the deep ocean means that the tidal wavelength there is of order 10,000 km. As the ocean basins have a similar size, they also have the potential of being resonant. In practice deep ocean resonances are difficult to observe, probably because the deep ocean loses tidal energy too rapidly to the resonant shelves.

title: Tidal resonance


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Lake monster

A lake monster is a lake-dwelling entity in folklore. The most famous example is the Loch Ness Monster. Depictions of lake monsters are often similar to those of sea monsters.

In the Motif-Index of Folk-Literature, entities classified as "lake monsters", such as the Scottish Loch Ness Monster, the American Chessie, and the Swedish Storsjöodjuret fall under B11.3.1.1. ("dragon lives in lake").

Theories
According to the Swedish naturalist and author Bengt Sjögren (1980), present-day lake monsters are variations of older legends of water kelpies. Sjögren claims that the accounts of lake-monsters have changed during history, as do others. Older reports often talk about horse-like appearances, but more modern reports often have more reptile and dinosaur-like appearances; he concludes that the legendary kelpies have evolved into the present day saurian lake-monsters since the discovery of dinosaurs and giant aquatic reptiles and the popularization of them in both scientific and fictional writings and art.

The stories cut across cultures, existing in some variation in many countries. and have undergone what Michel Meurger calls concretizing (The process of turning items, drawings, general beliefs and stories into a plausible whole) and naturalization over time as humanity's view of the world has changed.

In many of these areas, especially around Loch Ness, Lake Champlain and the Okanagan Valley, these lake monsters have become important tourist draws.

In Ben Radford and Joe Nickell's book Lake Monster Mysteries, the authors attribute a vast number of sightings to otter misidentifications. Ed Grabianowski plotted the distribution of North American lake monster sightings and then overlaid this with the distribution of the common otter and found a near perfect match. It turns out that three or four otters swimming in a line look remarkably like a serpentine, humped creature undulating through the water, very easy to mistake for a single creature if you see them from a distance. "This isn't speculation. I'm not making this up," Nickell said. "I've spoken to people who saw what they thought was a lake monster, got closer and discovered it was actually a line of otters. That really happens." Of course, not every supposed lake monster sighting can be attributed to otters, but it is an excellent example of how our perceptions can be fooled.

Paul Barrett and Darren Naish note that the existence of any large animals in isolation (i.e., in a situation where no breeding population exists) is highly unlikely. Naish also observes that the stories are likely remnants of tales meant to keep children safely away from the water.

There have been many purported sightings of lake monsters, and even some photographs, but each time these have either been shown to be deliberate deceptions, such as the Lake George Monster Hoax, or serious doubts about the veracity and verifiability have arisen, as with the famous Mansi photograph of Champ.

Examples
Well-known lake monsters include:
 * Mishipeshu, in Lake Superior, Canada and US
 * Nessie, in Loch Ness, Scotland
 * Morag, in Loch Morar, Scotland
 * Lagarfljót Worm, in Lagarfljót, Iceland
 * Ogopogo, in Okanagan Lake, Canada
 * Lariosauro, in Lake Como, Italy
 * Champ, in Lake Champlain, Canada and US
 * Memphre, in Lake Memphremagog, Canada and US
 * Bessie, in Lake Erie, Canada and US
 * Nahuelito, in Nahuel Huapi Lake, Argentina
 * Muyso, in Lake Tota, Colombia
 * Van Gölü Canavarı, in Lake Van, Turkey
 * Inkanyamba, in Howick Falls, South Africa
 * Tahoe Tessie, in Lake Tahoe, US
 * Flessie, in Flathead Lake, US
 * Iliamna Lake monster, in Lake Iliamna, US

title: Lake monster


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Arthur Baker (calligrapher)

Arthur Baker (c. 1930 – December 2016) was the creator of a distinctive and dramatic style of brush and pen calligraphy.

Biography
Baker grew up in Berkeley, California. He attended school on the West Coast of the United States and New York City, where he studied under Oscar Ogg, George Salter, and Tommy Tompson.

Baker studied letterforms and historical calligraphic styles, about which he wrote many books. Baker also designed typefaces, and his own pens and brushes.

Baker lived most of his life in Andover, Massachusetts. His hobbies included designing, making and flying paper airplanes.

Baker died in December 2016, at the age of 86. His archive is held at Letterform Archive

Typefaces

 * Amigo
 * Baker Sans—Eddie Bauer catalog logo and text.
 * Baker Signet—designed in 1965.
 * Calligraphica
 * Cold Mountain
 * Collier Script
 * Daybreak
 * Duckweed
 * Fish Face
 * Hiroshige
 * Kigali
 * Kigali Block
 * Kigali Decorative
 * Kigali ZigZag
 * Marigold
 * Mercator
 * Oak Graphic
 * Oxford
 * Pelican
 * Sassafras
 * Signet—Coca-Cola used Signet Bold for the word 'Coke' and Fleet Bank uses it for its logo.
 * Tiepolo—Lipton foods.
 * Visigoth

Books by Arthur Baker

 * Arthur Baker, Calligraphic Alphabets, (Dover, 1974)
 * Arthur Baker, The Roman Alphabet, (Art Direction Book Co., 1976) ISBN 0-910158-23-1
 * Arthur Baker, Dance of the pen, (Art Direction Book Co., 1978) ISBN 0-910158-45-2
 * Arthur Baker, New Calligraphic Ornaments and Flourishes, (Mineola: Dover, 1981)
 * Arthur Baker, Chancery Cursive: Stroke by Stroke, (Dover, 1982)
 * Arthur Baker, Cut and Assemble Paper Airplanes That Fly, (Dover, 1982)
 * Arthur Baker, Celtic Hand Stroke by Stroke (Irish Half-Uncial from "The Book of Kells"), (Dover, 1983)
 * Arthur Baker, Calligraphic cut paper designs for artists and craftsmen, (Mineola: Dover, 1983)
 * Arthur Baker, Calligraphic Swash Initials, (Dover, 1984)
 * Arthur Baker, Arthur Baker's Historic Calligraphic Alphabets, (Dover)
 * Arthur Baker, Encyclopedia of Calligraphy Styles

title: Arthur Baker (calligrapher)


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Talk:Arthur Baker (calligrapher)

Untitled
How about some more information about the style, when this person lived, and so on?

Also, full sentences are good.

Removed copyrighted material
I have reverted the article to a rather old version, in order to get rid of the content of two articles from other publications that were added to the article. In both cases, the editor claims to have permission, but the permission is not documented. If you wish to use text from other sources in such a way, please follow the procedures at Copyright problems to document the permission. --Alvestrand 11:34, 1 December 2007 (UTC)

General Notability
The header of this page questions whether the topic (Arthur Baker) meets Wikipedia's general notability guideline. As a typography and type design specialist, I can confirm that, among American calligraphers who have also made a name as type designers, Mr. Baker is one the most respected and influential. Online sources are scarce compared to printed ones, but I'll try to add some. — Preceding unsigned comment added by Jandorp (talk • contribs) 13:54, 6 September 2014 (UTC)

title: Talk:Arthur Baker (calligrapher)


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Talk:Mesotrophic lake

The article merely says what mesotrophic water is not. Can't it begin with a definition that says what it is? 131.183.137.36 20:46 11 Jul 2003 (UTC)

I think it's fixed up enough to say what it is now. Seem ok? Dmsar 20:54 11 Jul 2003 (UTC)

 * Napzilla (talk) 04:03, 5 July 2010 (UTC)

title: Talk:Mesotrophic lake


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Otto Schily

Otto Georg Schily (born 20 July 1932) is a former Federal Minister of the Interior of Germany, his tenure was from 1998 to 2005, in the cabinet of Chancellor Gerhard Schröder. He is a member of the Social Democratic Party of Germany (SPD).

Early life and education
Born in Bochum as the son of an iron works director, Schily grew up in a family of anthroposophists. His younger brother is Konrad Schily, an academic and also a politician. They spent their adolescence during the war in Bavaria. The family opposed Adolf Hitler. In 1962, he passed his second state exam after having studied law and politics in Munich, Hamburg, and Berlin, thus being admitted to the bar; a year later, he opened his own law practice.

On 2 June 1967 Schily went to a demonstration in Berlin against the violation of human rights in Iran. A student, Benno Ohnesorg, was shot dead by the police. He subsequently decided to represent the student's family.

In the 1970s, he became a public figure as a trial lawyer, defending several guerrilla activists of the left-wing Red Army Faction. In 1971, he represented his friend Horst Mahler, who much later would become an advocate of the fascist National Democratic Party. During the Stammheim trial (1975–1977), he was the only remaining attorney of Gudrun Ensslin. While he gained popularity and respect for acting according to his own moral principles, some accused him of supporting the radicals' goals.

Founding member of the Green Party
In 1980, Schily became founding member of the Green Party. In 1982, he joined other members of the Green Party for a meeting with Libyan leader Muammar Gaddafi, who offered to help groups allied with the European anti-nuclear movement to try to close United States military bases in Europe.

In the 1983 elections, Schily was elected to the German Bundestag and in the first electoral term in which the Greens were represented in parliament, he was one of the spokespersons of the parliamentary group, together with Petra Kelly and Marieluise Beck. In parliament, he became a leading exponent of the party's realist wing, which favored striving for a governing coalition with the Social Democrats following the 1987 elections. In 1986, he was the Greens' sole representative on a Bundestag committee investigating the so-called Flick affair. Due to the party's policy of rotating its representatives, he had to leave parliament in 1986, but he was re-elected in 1987.

Switch to the Social Democrats
Increasingly estranged from the fundamentalist wing of the Greens, particularly regarding alliances with larger parties, Schily left the party in 1989, resigned his seat in parliament, and joined the Social Democrats (SPD) instead – which he represented in the new Bundestag in 1990. In subsequent years, he was active in affairs of the former East Germany and in coordinating various legal policies of the SPD. Between 1994 and 1998, Schily served on the Committee on the Election of Judges (Wahlausschuss), which is in charge of appointing judges to the Federal Constitutional Court of Germany. He was also a member of the parliamentary body in charge of appointing judges to the Highest Courts of Justice, namely the Federal Court of Justice (BGH), the Federal Administrative Court (BVerwG), the Federal Fiscal Court (BFH), the Federal Labour Court (BAG), and the Federal Social Court (BSG).

Federal Minister of the Interior, 1998–2005
After Gerhard Schröder became chancellor in 1998, he appointed Schily as Federal Minister of the Interior. He was the oldest member of the cabinet.

During his time in office, Schily was frequently criticized for conservative policies, such as pushing through German anti-terrorist legislation after the 11 September 2001 terrorist attacks, which were seen as contradictory to his earlier beliefs. Under the new legislation, his ministry moved against Metin Kaplan’s radical Islamic group in December 2001, banning it and 19 associated organizations and carrying out more than 200 raids in seven cities.

Between 2001 and 2004, Schily led the government’s negotiations with the conservative opposition on a bill that made it easier for skilled workers to move to Germany but toughened controls on foreign militants. In 2004, he joined Italy in proposing the creation of the camps, possibly in Libya, to process potential immigrants and repatriate illegal arrivals to the EU.

In 2001, the parliamentary opposition called for Schily’s resignation in light of revelations that his ministry had failed to inform the Federal Constitutional Court that a key witness in the government’s petition to ban the far-right National Democratic Party (NPD) had worked as an undercover agent for the domestic intelligence service; the failure to notify the court later resulted in the suspension of the proceedings.

In 2005, Schily again came under pressure for authorizing a raid on the newsroom of Cicero magazine after it had published information from a secret Federal Criminal Police Office (BKA) report.

On 29 March 2007, Schily took responsibility for the handling of the case of Guantanamo detainee Murat Kurnaz, who was arrested in Pakistan in 2001, turned over to United States authorities and held at the U.S. prison camp in Cuba as a terror suspect. Kurnaz was released in 2006 and returned to Germany.

Following the 2005 elections and the formation of the new government of Chancellor of Germany Angela Merkel, Schily was succeeded in his post by Wolfgang Schäuble. Schily remained a member of parliament until 2009 and served on the Committee on Foreign Affairs. In 2008, he caused headlines when the German Bundestag on 22 April fined him €22,000 for failing to disclose the names of his law firm’s clients. Otto Schily opposed compulsory vaccination as unconstitutional in an article in Die Welt.

Life after politics
After serving as a minister, Schily became a supervisory board member of two companies for biometric technologies, raising questions as to whether or not he was capitalizing on his work as minister, regarding the implementation of biometric passports.

Between 2006 and 2007, Schily served as member of the Amato Group, a group of high-level European politicians unofficially working on rewriting the Treaty establishing a Constitution for Europe into what became known as the Treaty of Lisbon following its rejection by French and Dutch voters.

In 2015, Schily was accused of receiving money to lobby for the prosecution in Austria of Rakhat Aliyev, a former Kazakh official who turned against the Kazakh government.

In addition, Schily has held various paid and unpaid positions, including the following:
 * Deloitte Germany, Member of the Advisory Board
 * Schengen White List Project, Member of the Advisory Board
 * Hertha BSC Foundation, Member of the Board of Trustees
 * Investcorp, Member of the European Advisory Board (since 2006)
 * Ziegert Bank- und Immobilienconsulting, Member of the Advisory Board
 * DAPD News Agency, Member of the Advisory Board (2011-2012)
 * 2006 FIFA World Cup Organizing Committee, Member of the Supervisory Board (2005-2006)

Recognition
In 2005, Schily received the Leo Baeck Medal for his humanitarian work promoting tolerance and social justice.

title: Otto Schily


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Escape Velocity Nova

Escape Velocity Nova (a.k.a. EV Nova or EVN) is a video game developed by Ambrosia Software in collaboration with ATMOS. It is the third game in the Escape Velocity series of space trading and combat games. It was released on March 19, 2002 for Mac OS X and Mac OS 9, and later ported to Windows and released on July 11, 2003. The game's premise, set in a time period after mankind has discovered hyperspace technology, grants the player freedom to take missions, trade goods, steal from other ships, and enter one of six storylines.

Originally a plug-in for Escape Velocity Override created by ATMOS, Nova development began with Ambrosia contracting ATMOS to make the plug-in the scenario for a new game. ATMOS developed the scenario and graphics, while Matt Burch developed the game engine. The game features six different mutually exclusive plot lines, but players have control to act as they will from the start of the game. Reception to the game praised the gameplay, plot, and ability to be replayed, but was critical of the lack of a soundtrack, repetitiveness, and pace and difficulty of the storylines.

Gameplay and plot
In Escape Velocity Nova, the player is placed in command of a shuttlecraft in space. The game is played from a top-down perspective in 2D. A tutorial is offered, but players are granted freedom to act as they will at the start. Players can earn money by purchasing and trading goods, taking missions transporting people or goods to various locations, or by stealing from other ships. The player's ship moves between systems of planets by using a hyperspace jump. At various planets, the player can take on missions and trade goods, buy new ships, or outfit their current ship with new weapons and accessories. Ship classes vary from shuttlecraft to large frigates. There are six different storylines within the game that can be played; each one is mutually exclusive and a new game must be begun to play a different story. A player's choices in the plot can impact the political alignment of the entire map. If players become strong enough, they can demand tribute from a system. Doing so will cause the system to deploy its fleet of ships, but should the player defeat the fleet, the system recognizes the player as its warlord and pays tribute.

Escape Velocity Nova is a shareware game. Its status is enforced in game by a character named Captain Hector, who will continuously remind the player to pay their shareware fee. The game also supports plug-ins, allowing players to create their own ships and campaigns, but access to do so is disallowed if the shareware fee is not paid.

Set in the year 1177 N.C., Escape Velocity Nova's plot begins long after mankind has begun to explore outer space. Years before, a person named Omata Kane designed a "hypergate" system connecting systems of human-inhabited worlds that had been discovered by colonists from Earth. Terrorists destroyed the hypergate in the Sol system, which damaged the entire network. With this isolation, warlords arose and fell in the various disconnected systems. The later invention of hyperspace technology allowed for the lost systems to be reconnected, and resulted in order. Centered around Earth and the Sol system is the Federation, while to the south is the Auroran Empire, categorized as "a savage race". Another group, called the Polaris, hold the east, while the north and west are unexplored territory. The player, having just purchased a shuttle, is cast out to begin a life as the captain of their own ship.

Development
Nova began as a plug-in for Ambrosia Software's Escape Velocity Override in July 1998. A group of students from Tasmania: Dafydd Williams, Jason Cook, and Scott Vardy were fans of Override and began working on a modding project called Override Nova. Their updates on the project were shared on Ambrosia Software's website forums, which caught the attention of Ambrosia employee Andrew Welch. Shortly afterward, the student group took the name ATMOS Software and signed a contract with Ambrosia to work on a new game. Ambrosia Software's Matt Burch developed the game engine, while Welch managed the project and ATMOS developed the graphics and scenario. Burch, who had programmed Escape Velocity and Override, programmed Nova while also working a second job as an engineer. In July 2000, Ambrosia contracted ATMOS to convert the plug-in into the scenario for Nova. Development of the game from Override took approximately 12 months, with an additional 8 months of beta testing. Escape Velocity Nova was released on March 19, 2002 for Mac, and received both OS X and OS 9 releases. Later that year was announced to be receiving a Windows port, which was released on July 11, 2003. A 2008 update for Mac was built as a universal binary with native support for Intel processors.

Reception
Escape Velocity Nova received praise for its gameplay and game design, especially in light of it being a shareware game. MacAddict gave Escape Velocity Nova its Editor's Choice Award. Reviewer Chris Barylick stated that the gameplay is essentially the same as its predecessors, Escape Velocity and Override. He called the game "more beautifully designed than you could expect a shareware game to be". Two years after the game's release, Barylick said the game was still worth the download. In a review for Inside Mac Games, Richard Porcher expressed that Nova 's graphics were superior for a shareware game. Macworld's Peter Cohen lauded the combination of action-based space battles with adventure-style gaming. He noted the game made improvements over Nova 's predecessors while stating that Ambrosia Software "has wisely left alone what ain't broken."

The game's story and game length received more mixed reviews. Porcher stated that Nova 's strongest point is its ability to be replayed repeatedly, especially with support for plug-ins in the game. He also pointed out flaws with the storylines being too easy and the plot lines being mutually exclusive, but felt all would be addressed with plug-ins. PC Gamer 's J.T. Trollman gave praise for the game's story writing but was critical of the game's lengthy repetition and time span between points in the story. NomaD of Russian website Absolute Games praised the game's large map and scenario, while also critical of the game's lack of a soundtrack. By contrast, MacNN was critical of the small universe size and dialogue, though it called the game "extraordinary" and praised the game's replayability.

title: Escape Velocity Nova


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Detroit Dam

Detroit Dam is a gravity dam on the North Santiam River between Linn County and Marion County, Oregon. It is located in the Cascades, about 5 mi west of the city of Detroit. It was constructed between 1949 and 1953 by the United States Army Corps of Engineers. The dam created 400 ft deep Detroit Lake, more than 9 miles (14 km) long with 32 miles (51 km) of shoreline.

It is one of the dams authorized by the Flood Control Act of 1938. Construction was delayed largely due to World War II. The dam, dedicated on June 10, 1953, was authorized for the purposes of flood control, power generation, navigation, and irrigation. Other uses are fishery, water quality, and recreation. It was built in concert with the Big Cliff Dam downstream.

In 2021, the U.S. Army Corps of Engineers determined that this dam was at risk of failing in a large earthquake in the Cascadia subduction zone, which would result in a "potentially catastrophic flood", which could potentially affect Oregon's state capital, Salem, located downstream. For this reason, the level of the reservoir was lowered by five feet, to reduce the stress on the concrete structure.

Capacity
Source:
 * Drainage area: 437 mi2 (1,132 km2)
 * Maximum inflow: 63,200 ft3/s (1,790 m³/s) 1909
 * Lake Elevation
 * Maximum pool: 1,574 ft (480 m)
 * Full pool: 1,569 ft (478 m)
 * Minimum flood control pool: 1,450 ft (442 m)
 * Usable storage (1,425.0 to 1,563.5 ft) = 321000 acre.ft
 * Powerhouse
 * Number of units: 2
 * Nameplate capacity: 100 MW
 * Overload capacity: 115 MW
 * Hydraulic capacity: 5,340 ft3/s (151 m³/s)

title: Detroit Dam


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Military history of Britain

The Military history of Britain, including the military history of the United Kingdom and the military history of the island of Great Britain, is discussed in the following articles:

 * Military history of England: the military history of the nations and tribes that inhabited or occupied the lands that make up England and Wales, before the creation of the United Kingdom under the Act of Union in 1707.
 * Military history of Scotland: for the military history of Scotland since prehistoric times to today.
 * Military history of the United Kingdom: since its formation in 1707.

title: Military history of Britain


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Comparative anatomy

Comparative anatomy is the study of similarities and differences in the anatomy of different species. It is closely related to evolutionary biology and phylogeny (the evolution of species).

The science began in the classical era, continuing in the early modern period with work by Pierre Belon who noted the similarities of the skeletons of birds and humans.

Comparative anatomy has provided evidence of common descent, and has assisted in the classification of animals.

History

The first specifically anatomical investigation separate from a surgical or medical procedure is associated by Alcmaeon of Croton. Leonardo da Vinci made notes for a planned anatomical treatise in which he intended to compare the hands of various animals including bears. Pierre Belon, a French naturalist born in 1517, conducted research and held discussions on dolphin embryos as well as the comparisons between the skeletons of birds to the skeletons of humans. His research led to modern comparative anatomy.

Around the same time, Andreas Vesalius was also making some strides of his own. A young anatomist of Flemish descent made famous by a penchant for amazing charts, he was systematically investigating and correcting the anatomical knowledge of the Greek physician Galen. He noticed that many of Galen's observations were not even based on actual humans. Instead, they were based on other animals such as non-human apes, monkeys, and oxen. In fact, he entreated his students to do the following, in substitution for human skeletons, as cited by Edward Tyson : "If you can't happen to see any of these, dissect an Ape, carefully view each Bone, &c. ..." Then he advises what sort of Apes to make choice of, as most resembling a Man : And conclude "One ought to know the Structure of all the Bones either in a Humane Body, or in an Apes ; 'tis best in both ; and then to go to the Anatomy of the Muscles." Up until that point, Galen and his teachings had been the authority on human anatomy. The irony is that Galen himself had emphasized the fact that one should make one's own observations instead of using those of another, but this advice was lost during the numerous translations of his work. As Vesalius began to uncover these mistakes, other physicians of the time began to trust their own observations more than those of Galen. An interesting observation made by some of these physicians was the presence of homologous structures in a wide variety of animals which included humans. These observations were later used by Darwin as he formed his theory of Natural Selection.

Edward Tyson is regarded as the founder of modern comparative anatomy. He is credited with determining that whales and dolphins are, in fact, mammals. Also, he concluded that chimpanzees are more similar to humans than to monkeys because of their arms. Marco Aurelio Severino also compared various animals, including birds, in his Zootomia democritaea, one of the first works of comparative anatomy. In the 18th and 19th century, great anatomists like George Cuvier, Richard Owen and Thomas Henry Huxley revolutionized our understanding of the basic build and systematics of vertebrates, laying the foundation for Charles Darwin's work on evolution. An example of a 20th-century comparative anatomist is Victor Negus, who worked on the structure and evolution of the larynx. Until the advent of genetic techniques like DNA sequencing, comparative anatomy together with embryology were the primary tools for understanding phylogeny, as exemplified by the work of Alfred Romer.

Concepts

Two major concepts of comparative anatomy are:
 * 1) Homologous structures - structures (body parts/anatomy) which are similar in different species because the species have common descent and have evolved, usually divergently, from a shared ancestor.  They may or may not perform the same function. An example is the forelimb structure shared by cats and whales.
 * 2) Analogous structures - structures similar in different organisms because, in convergent evolution, they evolved in a similar environment, rather than were inherited from a recent common ancestor. They usually serve the same or similar purposes. An example is the streamlined torpedo body shape of porpoises and sharks. So even though they evolved from different ancestors, porpoises and sharks developed analogous structures as a result of their evolution in the same aquatic environment. This is known as a homoplasy.

Uses
Comparative anatomy has long served as evidence for evolution, now joined in that role by comparative genomics; it indicates that organisms share a common ancestor.

It also assists scientists in classifying organisms based on similar characteristics of their anatomical structures. A common example of comparative anatomy is the similar bone structures in forelimbs of cats, whales, bats, and humans. All of these appendages consist of the same basic parts; yet, they serve completely different functions. The skeletal parts which form a structure used for swimming, such as a fin, would not be ideal to form a wing, which is better-suited for flight. One explanation for the forelimbs' similar composition is descent with modification. Through random mutations and natural selection, each organism's anatomical structures gradually adapted to suit their respective habitats. The rules for development of special characteristics which differ significantly from general homology were listed by Karl Ernst von Baer as the laws now named after him.

title: Comparative anatomy


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Pinot blanc

Pinot blanc or Pinot bianco is a white wine grape. It is a point genetic mutation of Pinot noir. Pinot noir is genetically unstable and will occasionally experience a point mutation in which a vine bears all black fruit except for one cane which produces white fruit.

Origins and regional production
In Alsace, Germany, Luxembourg, Italy, Hungary, Czech Republic and Slovakia, the wine produced from this grape is a full-bodied white. In Germany, where it is known as Weißer Burgunder or Weißburgunder, there were 5540 ha of Pinot blanc in 2018. The most powerful versions are usually made in Baden and Palatinate. In 2018, there were 1232 ha of Pinot blanc in France, with most of the plantations found in Alsace, where it is used for both still white wines and is the most common variety used for sparkling wine, Crémant d'Alsace. Somewhat confusingly, the designation "Pinot blanc" for Alsace AOC wine does not necessarily mean that the wine is varietally pure Pinot blanc. (This is in difference to Pinot gris, which is a "true" varietal designation in Alsace.) Rather, the designation means that it is a white wine made from Pinot varieties. Under Alsace appellation rules, the varieties Pinot blanc, Auxerrois blanc, Pinot gris and Pinot noir (vinified white, without skin contact) may all be used, but a blend of Pinot blanc and Auxerrois blanc is the most common. The most full-bodied "Pinot blanc" wines from Alsace, with a spicy and smokey character and moderate acidity, are probably dominated by Auxerrois grapes.

Historically, Pinot blanc was used both in Burgundy and Champagne. It is still allowed in Bourgogne blanc blend and small amounts of Pinot blanc may in principle be blended into some Burgundy wines, but very small amounts are cultivated in either region. In the Champagne region, Pinot blanc is often called Blanc Vrai.

In the United States it is mainly produced in California. In the United States, many of the vines called Pinot blanc are actually a different variety, Melon de Bourgogne/Muscadet, that resembles Chardonnay when on the vine. This mistake was discovered around the mid-1980s by a French oenologist who was examining rootstock while visiting University of California, Davis, and now Pinot blanc purchased from a nursery will be the genuine article. The grape is also grown in Austria and Hungary as well as in Burgundy, France. In Canada, Pinot blanc is often used to make ice wine. Canada's Okanagan Valley has developed a reputation for Pinot blanc as its signature wine.

Pinot blanc has also been confused with Chardonnay, and wineries often vinify it in a similar style, using barrel fermentation, new oak and malolactic fermentation. It can also be treated more lightly and made into a crisper wine that still has some ability to age.

Relationship to other grapes
During a series of trials between 1930 and 1935, Pinot blanc was crossed with Riesling to create the white Italian wine grape variety Manzoni bianco.

Wine characteristics
In Alsace, Italy and Hungary, the wine produced from this grape is a full-bodied dry white wine while in Germany and Austria they can be either dry or sweet. One of the components of the wine Vin Santo can be Pinot blanc.

In France the grape is often blended with Klevner, sometimes referred to by locals as "true Pinot", and Auxerrois grapes, in order to give it a more Alsatian flavor.

Bottles labeled Pinot blanc offer fruity aromas, often of apple, citrus fruit, and floral characteristics. Bottles that are varietally pure, although more difficult to find, provide stronger floral characteristics, stone fruits and a headier minerality. Regardless of their exact composition, most wines under the label 'Pinot blanc' are rather high in acidity and are vinified in tank, though more prestigious examples are fermented in large, 100% used oak barrels. Pinot blanc wines are usually made for immediate consumption.

Names in other regions
Pinot blanc's name varies by region. In Austria it may be bottled as Weissburgunder or Klevner. Weissburgunder is also used in the Südtirol/Alto Adige region of north east Italy (also occasionally named so in Alsace) and in Germany. Hungary calls it Fehér Burgundi. Spain and Italy refer to it as Pinot bianco. In the Czech Republic it is known as Rulandské Bílé, in Slovakia Rulandské Biele and in Croatia Pinot bijeli or Burgundac bijeli. In Serbia it is called Бели пино, Бели бургундац, Пино блан.

title: Pinot blanc