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William Tinsley Keeton
William Tinsley Keeton (February 3, 1933 – August 17, 1980) was an American zoologist known internationally for his work on animal behavior, especially bird migration, and for his work on millipede taxonomy. He was a well-liked professor of biology at Cornell University in Ithaca, New York and author of a widely used introductory textbook, ''Biological Science''. Biography William Keeton was born February 3, 1933, in Roanoke, Virginia, and grew up in Lynchburg. Keeton attended the University of Chicago and received both his Bachelor of Arts and the Bachelor of Science degrees, working under Dr. Alfred E. Emerson. Keeton earned a master's degree at Virginia Polytechnic Institute (Virginia Tech), during which he revised the millipede genus '' Brachoria''. During his time at Virginia Tech, Keeton met Barbara Orcutt, whom he married in 1958. He moved to Cornell University in 1956 in order to continue his research with millipede systematics for his doctorate, where he studied unde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roanoke, Virginia
Roanoke ( ) is an independent city in the U.S. state of Virginia. At the 2020 census, the population was 100,011, making it the 8th most populous city in the Commonwealth of Virginia and the largest city in Virginia west of Richmond. It is located in the Roanoke Valley of the Roanoke Region of Virginia. Roanoke is the largest municipality in Southwest Virginia, and is the principal municipality of the Roanoke Metropolitan Statistical Area (MSA), which had a 2020 population of 315,251. It is composed of the independent cities of Roanoke and Salem, and Botetourt, Craig, Franklin, and Roanoke counties. Bisected by the Roanoke River, Roanoke is the commercial and cultural hub of much of Southwest Virginia and portions of Southern West Virginia. History Timeline * 1835 - Town of Gainesborough incorporated. * 1838 - Roanoke County created. * 1852 - Big Lick Depot built near Gainesborough; Virginia & Tennessee Railroad begins operating. * 1865 - April: Big Lick settlement sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brachoria
''Brachoria'' is a genus of polydesmidan millipedes in the family Xystodesmidae inhabiting the Eastern United States. Also known as the Appalachian mimic millipedes, at least 30 species are known, with highest diversity in the Appalachian Mountains, especially the Cumberland Plateau and Ridge and Valley Province. Species of ''Brachoria'' are boldly patterned with yellow, orange, red, violet that contrasts with a black background, and in the Appalachians some species mimic species of ''Apheloria'' where they co-occur, a phenomenon known as Müllerian mimicry Species There are over 30 species of ''Brachoria'' which differ mainly in characteristics of the male gonopods (reproductive appendages), but since many species have very small known ranges, geographic location can aid in identification as well. * ''Brachoria badbranchensis'' * ''Brachoria blackmountainensis'' * ''Brachoria calceata'' * ''Brachoria campcreekensis'' * ''Brachoria cedra'' * ''Brachoria conta'' * ''Bracho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnets
A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, cobalt, etc. and attracts or repels other magnets. A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. An everyday example is a refrigerator magnet used to hold notes on a refrigerator door. Materials that can be magnetized, which are also the ones that are strongly attracted to a magnet, are called ferromagnetic (or ferrimagnetic). These include the elements iron, nickel and cobalt and their alloys, some alloys of rare-earth metals, and some naturally occurring minerals such as lodestone. Although ferromagnetic (and ferrimagnetic) materials are the only ones attracted to a magnet strongly enough to be commonly considered magnetic, all other substances respond weakly to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homing Pigeon
The homing pigeon, also called the mail pigeon or messenger pigeon, is a variety of domestic pigeons (''Columba livia domestica'') derived from the wild rock dove, selective breeding, selectively bred for its ability to find its way home over extremely long distances. The rock dove has an innate homing ability, meaning that it will generally return to its nest using magnetoreception. Flights as long as have been recorded by birds in competitive pigeon racing. Their average flying speed over moderate distances is around and speeds of up to have been observed in top racers for short distances. In 2019 after sixty years a new world record was set in Netherlands for the fastest racing pigeon flight, distance flown 239 kilometers at speed above 143 kilometers per hour. Because of this skill, domesticated pigeons were used to carry messages as messenger pigeons. They are usually referred to as "pigeon post" if used in post service, or "war pigeon" during wars. Until the introducti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artificial Heart Valve
An artificial heart valve is a one-way valve implanted into a person's heart to replace a heart valve that is not functioning properly (valvular heart disease). Artificial heart valves can be separated into three broad classes: mechanical heart valves, bioprosthetic tissue valves and engineered tissue valves. The human heart contains four valves: tricuspid valve, pulmonary valve, mitral valve and aortic valve. Their main purpose is to keep blood flowing in the proper direction through the heart, and from the heart into the major blood vessels connected to it (the pulmonary artery and the aorta). Heart valves can malfunction for a variety of reasons, which can impede the flow of blood through the valve ( stenosis) and/or let blood flow backwards through the valve ( regurgitation). Both processes put strain on the heart and may lead to serious problems, including heart failure. While some dysfunctional valves can be treated with drugs or repaired, others need to be replaced wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heart Attack
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may travel into the shoulder, arm, back, neck or jaw. Often it occurs in the center or left side of the chest and lasts for more than a few minutes. The discomfort may occasionally feel like heartburn. Other symptoms may include shortness of breath, nausea, feeling faint, a cold sweat or feeling tired. About 30% of people have atypical symptoms. Women more often present without chest pain and instead have neck pain, arm pain or feel tired. Among those over 75 years old, about 5% have had an MI with little or no history of symptoms. An MI may cause heart failure, an irregular heartbeat, cardiogenic shock or cardiac arrest. Most MIs occur due to coronary artery disease. Risk factors include high blood pressure, smoking, diabetes, lack of e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zoology
Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the Animal, animal kingdom, including the anatomy, structure, embryology, evolution, Biological classification, classification, Ethology, habits, and distribution of all animals, both living and extinction, extinct, and how they interact with their ecosystems. The term is derived from Ancient Greek , ('animal'), and , ('knowledge', 'study'). Although humans have always been interested in the natural history of the animals they saw around them, and made use of this knowledge to domesticate certain species, the formal study of zoology can be said to have originated with Aristotle. He viewed animals as living organisms, studied their structure and development, and considered their adaptations to their surroundings and the function of their parts. The Greek physician Galen studied human anatomy and was one of the greatest surgeons of the a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Botany
Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek word (''botanē'') meaning " pasture", " herbs" "grass", or " fodder"; is in turn derived from (), "to feed" or "to graze". Traditionally, botany has also included the study of fungi and algae by mycologists and phycologists respectively, with the study of these three groups of organisms remaining within the sphere of interest of the International Botanical Congress. Nowadays, botanists (in the strict sense) study approximately 410,000 species of land plants of which some 391,000 species are vascular plants (including approximately 369,000 species of flowering plants), and approximately 20,000 are bryophytes. Botany originated in prehistory as herbalism with the efforts of early humans to identify – and later cultivate – ed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olfactory Navigation
Olfactory navigation is a hypothesis put forward to explain navigation and homing of pigeons, in particular the homing pigeon. There are two principal versions. Papi's mosaic model proposes that pigeons construct a map from the distribution of environmental odours, within a radius of 70-100 kilometres. Wallraff's gradient theory overcomes the problem of distance limitation by proposing the existence of long-range, stable atmospheric odour gradients. However, the evidence to suggest that pigeons use an ‘olfactory map’ in order to home is not conclusive. Background Homing can be defined as the ability to return to a set point from potentially anywhere on the earth's surface, including destinations that are unfamiliar. There are two criteria needed to coordinate this task, a compass sense (a sense of direction) and a map sense (a sense of location). It is the ability to return from unfamiliar locations that posed the question of what sensory cues are used to determine locati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth's Magnetic Field
Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun. The magnetic field is generated by electric currents due to the motion of convection currents of a mixture of molten iron and nickel in Earth's outer core: these convection currents are caused by heat escaping from the core, a natural process called a geodynamo. The magnitude of Earth's magnetic field at its surface ranges from . As an approximation, it is represented by a field of a magnetic dipole currently tilted at an angle of about 11° with respect to Earth's rotational axis, as if there were an enormous bar magnet placed at that angle through the center of Earth. The North geomagnetic pole actually represents the South pole of Earth's magnetic field, and conversely the South geomagnetic pole corresponds to the north pole of Earth's magnetic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Entomology
Entomology () is the science, scientific study of insects, a branch of zoology. In the past the term "insect" was less specific, and historically the definition of entomology would also include the study of animals in other arthropod groups, such as arachnids, myriapods, and crustaceans. This wider meaning may still be encountered in informal use. Like several of the other fields that are categorized within zoology, entomology is a taxon-based category; any form of scientific study in which there is a focus on insect-related inquiries is, by definition, entomology. Entomology therefore overlaps with a cross-section of topics as diverse as molecular genetics, behavior, neuroscience, biomechanics, biochemistry, systematics, physiology, developmental biology, ecology, morphology (biology), morphology, and paleontology. Over 1.3 million insect species have been described, more than two-thirds of all known species. Some insect species date back to around 400 million years ago. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal Navigation
Animal navigation is the ability of many animals to find their way accurately without maps or instruments. Birds such as the Arctic tern, insects such as the monarch butterfly and fish such as the salmon regularly migrate thousands of miles to and from their breeding grounds, and many other species navigate effectively over shorter distances. Dead reckoning, navigating from a known position using only information about one's own speed and direction, was suggested by Charles Darwin in 1873 as a possible mechanism. In the 20th century, Karl von Frisch showed that honey bees can navigate by the sun, by the polarization pattern of the blue sky, and by the earth's magnetic field; of these, they rely on the sun when possible. William Tinsley Keeton showed that homing pigeons could similarly make use of a range of navigational cues, including the sun, earth's magnetic field, olfaction and vision. Ronald Lockley demonstrated that a small seabird, the Manx shearwater, could orient itse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
