The Laplace operator is named after the French mathematician Pierre-Simon de Laplace (1749–1827), who first applied the operator to the study of celestial mechanics. In this case, the operator gives a constant multiple of the mass density—when it is applied to a given gravitational potential. Solutions of the equation ∆"f" = 0, now called Laplace's equation, are the so-called harmonic functions, and represent the possible gravitational fields in free space.
The Laplacian occurs in differential equations that describe many physical phenomena, such as electric and gravitational potentials, the diffusion equation for heat and fluid flow, wave propagation, and quantum mechanics. The Laplacian represents the flux density of the gradient flow of a function. For instance, the net rate at which a chemical dissolved in a fluid moves toward or away from some point is proportional to the Laplacian of the chemical concentration at that point; the resulting equation is the diffusion equation. For these reasons, the Laplace operator is used in the sciences for modelling all kinds of physical phenomena. In image processing and computer vision, the Laplacian operator has been used for various tasks such as blob and edge detection.
ERA
ERA may refer to:
Bull Shoals Lake
Bull Shoals Lake is an artificial lake or reservoir. It is in the Ozark Mountains of northern Arkansas and southern Missouri. Bull Shoals has hundreds of miles of lake arms and coves. This makes it good for boating, water sports, swimming, and fishing. Nineteen developed parks around the shoreline. These provide campgrounds, boat launches, swim areas, and marinas.
Bull Shoals Dam was created to impound (hold water in a reservoir) the White River. Bull Shoals has one of the largest concrete dams in the United States. It was the 5th largest dam in the world when the project was started. Work on the dam began in 1947 and was completed in 1951. In 1952 it was dedicated by President Harry S. Truman At least seven small family cemeteries and 20 larger cemeteries were carefully moved to make room for the new lake.
Bull Shoals Lake is the last reservoir on the White River before it enters the Mississippi River. The other three are Beaver Lake, Table Rock Lake and Lake Taneycomo. Bull Shoals lake is controlled by the Army Corps of Engineers and has the primary purpose of flood control. The level of the lake changes regularly. The normal pool level elevation is 654 feet above sea level, which is locally known as 'powerpool'. However, the elevation changes between 630 and 680 feet.
The upper part of the lake, below nearby Powersite Dam, is known as the "Pothole". The dam is designed for a maximum elevation of 695 feet (top of the flood pool). Bull Shoals Lake covers 45,000 acres (182 km²) with a 700-mile (1,120-km) shoreline at powerpool. It expands to more than 70,000 acres (284 km²)with a 1,000-mile (1,600-km) shoreline at 690 feet. The bottom of the lake consists of bedrock with very little vegetation. The shoreline of the lake is protected by a buffer zone (locally called the 'take line'). This area is owned, managed, and controlled by the Army Corps of Engineers. There is very little development around Bull Shoals. Most of the shoreline is heavily forested.
The Bull Shoals-White River State Park is a 725-acre (2.9 km²) park in Baxter and Marion Counties of Arkansas. It lies both above and below the large dam. Facilities, including camping, pavilions, docks and a nature center, stretch along the banks of the White River. The park offers 103 riverside campsites and 20 tent sites. Two rent-a-camp and two rent-a-RV sites are also available. Picnic areas and pavilions are scattered throughout the park. There are trails through the surrounding woods. A marina contains boating equipment and also rents boats. The visitors' center offers programs, workshops, camps, boating and fishing exhibits and an aquarium. Tours of the power generation plant and other dam facilities are available for a fee.
Table Rock is one of the premier Largemouth bass fishing lakes in the United States. The best time for bass fishing is between March and May. This is when the bass spawn in the shallows. Bull Shoals Lake is Arkansas's largest lake, and is also well known as a trout hot spot. Rainbow trout and brown trout of record size have been caught in the lake, with bream, catfish, crappie and largemouth bass also plentiful. Swimming and other watersports are also welcome at the lake. Arkansas Highway 178 runs along the top of Bull Shoals Dam and into the park.
Record rainfall in the spring of 2008 caused Bull Shoals to reach its highest water level since 1957. The lake crested at 695.02 feet above sea level. The Army Corps of Engineers opened the floodgates to stop the lake from more flooding.
Wave equation
Equations that describe waves as they occur in nature are called wave equations. Waves as they occur in rivers, lakes, and oceans are similar to those of sound and light. The problem of having to describe waves arises in fields like acoustics, electromagnetics, and fluid dynamics.
Historically, the problem of a vibrating string such as that of a musical instrument was studied by Jean le Rond d'Alembert, Leonhard Euler, Daniel Bernoulli, and Joseph-Louis Lagrange. In 1746, d’Alambert discovered the one-dimensional wave equation, and within ten years Euler discovered the three-dimensional wave equation.
Theo James
Theodore Peter James Kinnaird Taptiklis (born 16 December 1984), simply known as Theo James, is an English actor. He is known for portraying Jed Harper in "Bedlam", Walter William Clark, Jr. in the crime drama "Golden Boy" and as "Four", a military instructor, in the film adaptation of Veronica Roth's dystopian sci-fi novel, "Divergent".
Clara's Heart
Clara's Heart is a 1988 drama movie. This movie is about a family in crisis. Whoopi Goldberg plays the title character.
The movie got bad reviews from critics. Roger Ebert gave the movie one and a half stars.
Regulate...G Funk Era
Regulate...G Funk Era is a 1994 music album by Warren G. The title track samples the single "I Keep Forgettin'" by singer Michael McDonald. Other songs on the album also have samples. The album entered the US "Billboard" Top 200 Album Chart at #2.
The reviews of the critics were positive.
Miss Beazley (dog)
Miss Beazley (October 28, 2004 – May 17, 2014) was an American Scottish Terrier. She belonged to former U.S. President George W. Bush and former U.S. First Lady Laura Bush. She was best known for starring in BarneyCam videos with her half-brother Barney, who died in February 2013.
Miss Beazley died from lymphoma on May 17, 2014 in Dallas, Texas. She was 9. Barney also died from lymphoma.
Dumb and Dumber
Dumb and Dumber is a 1994 American comedy road movie. This movie is about two men who are roommates and best friends. They live in Providence, Rhode Island and drive to Aspen, Colorado. Jim Carrey and Jeff Daniels play the roommates. Lauren Holly plays Mary. Teri Garr plays Helen.
The movie was released on December 16, 1994 by Warner Bros. The reviews it received were very good. The movie was a box office success.
A prequel, "Dumb and Dumberer", was released in 2003. A sequel, "Dumb and Dumber To", was released in 2014.
Everybody's Fine
Everybody's Fine is a 2009 comedy-drama movie. It is about secrets and dysfunctional family. Robert De Niro plays Frank Goode. Drew Barrymore plays Rosie. Kate Beckinsale plays Amy.
The movie got mixed reviews from the critics. It was released in December 2009.
The Perks of Being a Wallflower
The Perks of Being a Wallflower is a 2012 American drama movie. This movie is about issues of LGBT, partner dances and child abuse. Logan Lerman plays Charlie Kelmeckis. Emma Watson plays Sam. Ezra Miller plays Patrick.
The movie was released in September 2012. Reviews were mostly positive. The box office was also positive. The movie is based on the book with the same title by Stephen Chbosky.
Riding in Cars with Boys