DomainTools.com |
 |
||
|
|
||
English Wikipedia references for Pnas.org 1-50 of 1985
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | >>
| Language: | ||||||||||||
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
|
| Articles: | 1,985 |
302 |
148 |
205 |
129 |
83 |
44 |
67 |
72 |
94 |
38 |
85 |
| Agriculture Agriculture refers to the production of food and goods through farming and forestry. Agriculture was the key development that led to the rise of civilization, with the husbandry of domesticated animals and plants (i.e. crops) creating food surpluses that enabled the development of more densely populated and stratified societies. The study of agriculture is known as agricultural science (the related practice of gardening is studied in horticulture). Agriculture | |
| Anthophyta anthophytes were thought to be a clade comprising plants bearing flower-like structures. The group contained the angiosperms - the extant flowering plants - as well as the Gnetales and the extinct Bennettitales.Detailed morphological and molecular studies have shown that the group is not actually monophyletic. Anthophyta | |
| Asterales The Asterales are an order of dicotyledonous flowering plants which include the composite family Asteraceae (sunflowers, daisies, thistles etc.) and its related families.The order is cosmopolitic, and includes mostly herbaceous species, although a small number of trees (Lobelia) and shrubs is also present. Asterales | |
| Aspirin Aspirin (USAN), also known as acetylsalicylic acid (, abbreviated ASA), is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication.Aspirin also has an antiplatelet, or "anti-coagulate", effect by inhibiting thromboxane prostaglandins, which under normal circumstances bind platelet molecules together to repair damaged blood vessels. Aspirin | |
| Adenosine triphosphate Adenosine-5'-triphosphate (ATP) is a multifunctional nucleotide, and plays an important role in cell biology as a coenzyme that is the "molecular unit of currency" of intracellular energy transfer. In this role, ATP transports chemical energy within cells for metabolism. Adenosine_triphosphate | |
| Antibiotic resistance Antibiotic resistance is the ability of a microorganism to withstand the effects of antibiotics. It is a specific type of drug resistance. Antibiotic resistance evolves via natural selection acting upon random mutation, but it can also be engineered by applying an evolutionary stress on a population. Antibiotic_resistance | |
| Arab An Arab (, ʿarabi) is a person who identifies as such on ethnic, linguistic or cultural grounds. The plural form, Arabs (العرب al-ʿarab), refers to the ethnocultural group at large.Though the Arabic language is older, Arabic culture was first spread in the Middle East beginning in the 2nd century as culturally Arab Christians such as the Ghassanids, Lakhmids and Banu Judham began migrating into the Syrian Desert and the Levant. Arab | |
| Ant Ants are social insects of the family Formicidae (), and along with the related wasps and bees, they belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130diversified after the rise of flowering plants. Today, more than 12,000 species are classified with upper estimates of about 14,000 species. They are easily identified by their elbowed antennae and a distinctive node-like structure that forms a slender waist. Ant | |
| Ames test Ames test is a biological assay to assess the mutagenic potential of chemical compounds. A positive test indicates that the chemical might act as a carcinogen (although a number of false-positives and false-negatives are known). As cancer is often linked to DNA damage, the test also serves as a quick assay to estimate the carcinogenic potential of a compound since it is difficult to ascertain whether standard carcinogen assays on rodents were successful. Ames_test | |
| Alpha helix A common motif in the secondary structure of proteins, the alpha helix (α-helix) is a right- or left-handed coiled conformation, resembling a spring, in which every backbone N-H group donates a hydrogen bond to the backbone C=O group of the amino acid four residues earlier ( hydrogen bonding). This secondary structure is also sometimes called a classic Pauling-Corey-Branson alpha helix (see below). (See also helix.) Alpha_helix | |
| Bead A bead is a small, decorative object that is pierced for threading or stringing. Beads range in size from under a millimeter to over a centimeter or sometimes several centimeters in diameter. Bead | |
| Bacteria Talk:Bacteria | |
| Biochemistry Biochemistry is the study of the chemical processes in living organisms. It deals with the structure and function of cellular components such as proteins, carbohydrates, lipids, nucleic acids and other biomolecules.Although there are a vast number of different biomolecules many are complex and large molecules (called polymers) that are composed of similar repeating subunits (called monomers). Biochemistry | |
| Big Bang The Big Bang is a cosmological model of the initial conditions and subsequent development of the universe. It is supported by the most comprehensive and accurate explanations from current scientific evidence and observation. As used by cosmologists, the term Big Bang generally refers to the idea that the universe has expanded from a primordial hot and dense initial condition at some finite time in the past, and continues to expand to this day. Big_Bang | |
| Bacillus thuringiensis Bacillus thuringiensis (or Bt) is a Gram-positive, soil-dwelling bacterium, commonly used as a pesticide. Additionally, B. thuringiensis also occurs naturally in the gut of caterpillars of various types of moths and butterflies, as well as on the dark surface of plants. Bacillus_thuringiensis | |
| Bipedalism Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs, or legs. An animal or machine that usually moves in a bipedal manner is known as a biped (), meaning "two feet" (from the Latin bi for "two" and ped for "foot"). Bipedalism | |
| Bacterial conjugation Bacterial conjugation is the transfer of genetic material between bacteria through direct cell-to-cell contact. Discovered in 1946 by Joshua Lederberg and Edward Tatum, conjugation is a mechanism of horizontal gene transfer—transformation and transduction—Bacterial conjugation is often incorrectly regarded as the bacterial equivalent of sexual reproduction or mating. Bacterial_conjugation | |
| Black Death Black Death was one of the deadliest pandemics in human history, peaking in Europe between 1348 and 1350. It is widely thought to have been caused by a bacterium named Yersinia pestis (Plague). Black_Death | |
| Biotechnology Biotechnology is technology based on biology, especially when used in agriculture, food science, and medicine. United Nations Convention on Biological Diversity defines biotechnology asBiotechnology is often used to refer to genetic engineering technology of the 21st century, however the term encompasses a wider range and history of procedures for modifying biological organisms according to the needs of humanity, going back to the initial modifications of native plants into improved food crops through artificial selection and hybridization. Biotechnology | |
| Transgenic maize Transgenic maize (corn) has been deliberately genetically modified to have agronomically desirable traits. Traits that have been engineered into corn are resistance to herbicides and incorporation of a gene that codes for the Bacillus thuringiensis (Bt) toxin, protecting plants from insect pests. Hybrids with both herbicide and pest resistance have also been produced. Transgenic maize is currently grown commercially in the United States. Transgenic_maize | |
| Cooking For a topical guide to this subject, see Outline of cooking.Cooking is the process of preparing food by applying heat, selecting, measuring and combining of ingredients in an ordered procedure for producing safe and edible food. The process encompasses a vast range of methods, tools and combinations of ingredients to alter the flavor, appearance, texture, or digestibility of food. Cooking | |
| Creutzfeldt–Jakob disease Creutzfeldt or CJD (IPA pronunciationdegenerative neurological disorder (brain disease) that is very rare, incurable, and invariably fatal. Among the types of transmissible spongiform encephalopathy found in humans, it is the most common. Creutzfeldt–Jakob_disease | |
| Cadmium Cadmium () is a chemical element with the symbol Cd and atomic number 48. The soft, bluish-white transition metal is chemically similar to the two other metals in group 12 , zinc and mercury. Similar to zinc it prefers oxidation state +2 in most of its compounds and similar to mercury it shows a low melting point for a transition metal. Cadmium is a relatively abundant element. Cadmium was discovered in 1817 by Friedrich Strohmeyer as an impurity in zinc carbonate. Cadmium | |
| Cretaceous–Tertiary extinction event The Cretaceous–Tertiary extinction event, which occurred approximately (Ma), was a large-scale mass extinction of animal and plant species in a geologically short period of time. Widely known as the K–T extinction event, it is associated with a geological signature known as the K–T boundary, usually a thin band of sedimentation found in various parts of the world. Cretaceous–Tertiary_extinction_event | |
| Cretaceous–Tertiary extinction event Talk:Cretaceous–Tertiary_extinction_event | |
| Cytosine Cytosine is one of the four main bases found in DNA and RNA. It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and a keto group at position 2). The nucleoside of cytosine is cytidine. In Watson-Crick base pairing, it forms three hydrogen bonds with guanine. Cytosine | |
| Chloroplast Chloroplasts are organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis. Chloroplasts capture light energy to conserve free energy in the form of ATP and reduce NADP to NADPH through a complex set of processes called photosynthesis. Chloroplast | |
| Chromosome chromosome is an organized structure of DNA and protein that is found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions. The word chromosome comes from the Greek (chroma, color) and (soma, body) due to their property of being very strongly stained by particular dyes. organisms. The DNA molecule may be circular or linear, and ca Chromosome | |
| Cnidaria Cnidaria | |
| Cytosol cytosol or intracellular fluid (or cytoplasmic matrix) is the liquid found inside cells. In eukaryotes this liquid is separated by cell membranes from the contents of the organelles suspended in the cytosol, such as the mitochondrial matrix inside the mitochondrion. Cytosol | |
| Chlorophyll Chlorophyll | |
| Central nervous system central nervous system (CNS) is the part of the nervous system that functions to coordinate the activity of all parts of the bodies of multicellular organisms. In vertebrates, the central nervous system is enclosed in the meninges. It contains the majority of the nervous system and consists of the brain and the spinal cord. Central_nervous_system | |
| Cosmic microwave background radiation Talk:Cosmic_microwave_background_radiation | |
| Common Chimpanzee The Common Chimpanzee (Pan troglodytes), also known as the Robust Chimpanzee, is a great ape. The name troglodytes, Greek for 'cave-dweller', was coined by Johann Friedrich Blumenbach in his Handbuch der Naturgeschichte (Handbook of Natural History) published in 1779. Colloquially, it is often called the chimpanzee (or simply 'chimp'), though technically this term refers to both species in the genus Pan:Bonobo, or Pygmy Chimpanzee. Common_Chimpanzee | |
| Dravidian languages The Dravidian family of languages includes approximately 73 languages , spoken by around 200 million people. They are mainly spoken in southern India and parts of eastern and central India as well as in northeastern Sri Lanka, Pakistan, Nepal, Bangladesh, Afghanistan, Iran, and overseas in other countries such as Malaysia and Singapore. Dravidian_languages | |
| DNA Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information. DNA is often compared to a set of blueprints or a recipe, or a code, since it contains the instructions needed to construct other components of cells, such as proteins and RNA molecules. DNA | |
| Deforestation Deforestation is the logging and/or burning of trees in the forested area. There are several reasons for doing socharcoal can be sold as a commodity and used by humans, while cleared land is used as pasture, plantations of commodities and human settlement. The removal of trees without sufficient reforestation has resulted in damage to habitat, biodiversity loss and aridity. Deforested regions often degrade into wasteland. Deforestation | |
| Dyslexia Dyslexia is a learning disability that makes itself manifest primarily as a difficulty with the visual notation of speech or written language, particularly with reading the various man-made writing systems. It is separate and distinct from reading difficulties resulting from other causes, such as a non-neurological deficiency with vision or hearing, or from poor or inadequate reading instruction, This suggests that dyslexia results from differences in how the brain processes written and spoken language. Dyslexia | |
| Dinosaur Dinosaurs (Greek δεινόσαυρος, deinosauros) were the dominant vertebrate animals of terrestrial ecosystems for over 160Triassic period (about 230million years ago) until the end of the Cretaceous period (65Cretaceous–Tertiary extinction event. The living species of birds may be classified as dinosaurs.The term "dinosaur" was coined in 1842 by Sir Richard Owen and derives from Greek δεινός (deinos) "terrible, powerful, wondrous" + σαῦρος (sauros) "lizard". Dinosaur | |
| Desmothoracid The desmothoracids are a group of heliozoan protists, usually sessile and found in freshwater environments. Each adult is a spherical cell around 10-20 μm in diameter surrounded by a perforated organic lorica or shell, with many radial pseudopods projecting through the holes to capture food. Desmothoracid | |
| Dynamical system Talk:Dynamical_system | |
| Evolution In biology, evolution is the change in the genetic material of a population of organisms from one generation to the next. Though the changes produced in any one generation are small, differences accumulate with each generation and can, over time, cause substantial changes in the organisms. Evolution | |
| Ernst W. Mayr Ernst Walter Mayr (July 5, 1904, Kempten, Germany February 3, 2005, Bedford, Massachusetts U.S.), was one of the 20th century's leading evolutionary biologists. He was also a renowned taxonomist, tropical explorer, ornithologist, historian of science, and naturalist. His work contributed to the conceptual revolution that led to the modern evolutionary synthesis of Mendelian genetics, systematics, and Darwinian evolution, and to the development of the biological species concept. Ernst_W._Mayr | |
| Elephant Elephants are large land mammals of the order Proboscidea and the family Elephantidae. There are three living species:African Bush Elephant, the African Forest Elephant and the Asian Elephant (also known as the Indian Elephant). Other species have become extinct since the last ice age, the Mammoths, dwarf forms of which may have survived as late as 2,000 BC, being the best-known of these. They were once classified along with other thick skinned animals in a now invalid order, Pachydermata. Elephant | |
| Eocene The Eocene epoch, lasting from 55.8 ± 0.2 to 33.9 ± 0.1 Ma (million years ago), is a major division of the geologic timescale and the second epoch of the Palaeogene period in the Cenozoic era. The Eocene spans the time from the end of the Paleocene epoch to the beginning of the Oligocene epoch. Eocene | |
| Erosion For morphological image processing operations, see Erosion (morphology)For use of in dermatopathology, see Erosion (dermatopathology)Erosion is the removal of solids (sediment, soil, rock and other particles) in the natural environment. It usually occurs due to transport by wind, water, or ice; by down-slope creep of soil and other material under the force of gravity; or by living organisms, such as burrowing animals, in the case of bioerosion. Erosion | |
| Extinction event An extinction event (also known asmass extinction; extinction-level event, ELE) is a sharp decrease in the number of species in a relatively short period of time. Mass extinctions affect most major taxonomic groups present at the time — birds, mammals, reptiles, amphibians, fish, invertebrates and other simpler life forms. They may be caused by one or both of extinction of an unusually large number of species in a short period. a sharp drop in the rate of speciation. Extinction_event | |
| Ethanol Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug, best known as the type of alcohol found in alcoholic beverages and in modern thermometers. Ethanol is one of the oldest recreational drugs. Ethanol | |
| Human evolution Human evolution, or anthropogenesis, is the part of biological evolution concerning the emergence of Homo sapiens as a distinct species from other hominins, great apes and placental mammals. It is the subject of a broad scientific inquiry that seeks to understand and describe how this change occurred. The study of human evolution encompasses many scientific disciplines, most notably physical anthropology, primatology, archaeology, linguistics and genetics. Human_evolution | |
| Edwin Hubble Edwin Powell Hubble (November 29, 1889 – September 28, 1953) was an American astronomer. He profoundly changed our understanding of the universe by demonstrating the existence of other galaxies besides the Milky Way. He also discovered that the degree of redshift observed in light coming from a galaxy increased in proportion to the distance of that galaxy from the Milky Way. This became known as Hubble's law, and would help establish that the universe is expanding. Edwin_Hubble |
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | >>
