Portal:Science

A CBC specimen in front of a printout displaying CBC and differential results

A complete blood count (CBC), also known as a full blood count (FBC), is a set of medical laboratory tests that provide information about the cells in a person's blood. The CBC indicates the counts of white blood cells, red blood cells and platelets, the concentration of hemoglobin, and the hematocrit (the volume percentage of red blood cells). The red blood cell indices, which indicate the average size and hemoglobin content of red blood cells, are also reported, and a white blood cell differential, which counts the different types of white blood cells, may be included.

The CBC is often carried out as part of a medical assessment and can be used to monitor health or diagnose diseases. The results are interpreted by comparing them to reference ranges, which vary with sex and age. Conditions like anemia and thrombocytopenia are defined by abnormal complete blood count results. The red blood cell indices can provide information about the cause of a person's anemia such as iron deficiency and vitamin B12 deficiency, and the results of the white blood cell differential can help to diagnose viral, bacterial and parasitic infections and blood disorders like leukemia. Not all results falling outside of the reference range require medical intervention. (Full article...)

The orca or killer whale (Orcinus orca) is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus Orcinus and is recognizable by its black-and-white patterned body. A cosmopolitan species, orcas can be found in all of the world's oceans in a variety of marine environments, from Arctic and Antarctic regions to tropical seas.

Orcas have a diverse diet, although individual populations often specialize in particular types of prey. Some feed exclusively on fish, while others hunt marine mammals such as seals and other species of dolphin. They have been known to attack baleen whale calves, and even adult whales. Orcas are apex predators, as they have no natural predators. They are highly social; some populations are composed of very stable matrilineal family groups (pods) which are the most stable of any animal species. Their sophisticated hunting techniques and vocal behaviours, which are often specific to a particular group and passed across generations, have been described as manifestations of animal culture. (Full article...)

Male

The white-winged fairywren (Malurus leucopterus) is a species of passerine bird in the Australasian wren family, Maluridae. It lives in the drier parts of Central Australia; from central Queensland and South Australia across to Western Australia. Like other fairywrens, this species displays marked sexual dimorphism and one or more males of a social group grow brightly coloured plumage during the breeding season. The female is sandy-brown with light-blue tail feathers; it is smaller than the male, which, in breeding plumage, has a bright-blue body, black bill, and white wings. Younger sexually mature males are almost indistinguishable from females and are often the breeding males. In spring and summer, a troop of white-winged fairywrens has a brightly coloured older male accompanied by small, inconspicuous brown birds, many of which are also male. Three subspecies are recognised. Apart from the mainland subspecies, one is found on Dirk Hartog Island, and another on Barrow Island off the coast of Western Australia. Males from these islands have black rather than blue breeding plumage.

The white-winged fairywren mainly eats insects, supplementing this with small fruits and leaf buds. It occurs in heathland and arid scrubland, where low shrubs provide cover. Like other fairywrens, it is a cooperative breeding species, and small groups of birds maintain and defend territories year-round. Groups consist of a socially monogamous pair with several helper birds who assist in raising the young. These helpers are progeny that have attained sexual maturity but remain with the family group for one or more years after fledging. Although not yet confirmed genetically, the white-winged fairywren may be promiscuous and assist in raising the young from other pairings. As part of a courtship display, the male wren plucks petals from flowers and displays them to female birds. (Full article...)

Davenport in 1912

Homer Calvin Davenport (March 8, 1867 – May 2, 1912) was a political cartoonist and writer from the United States. He is known for drawings that satirized figures of the Gilded Age and Progressive Era, most notably Ohio Senator Mark Hanna. Although Davenport had no formal art training, he became one of the highest paid political cartoonists in the world. Davenport also was one of the first major American breeders of Arabian horses and one of the founders of the Arabian Horse Club of America.

A native Oregonian, Davenport developed interests in both art and horses as a young boy. He tried a variety of jobs before gaining employment as a cartoonist, initially working at several newspapers on the West Coast, including The San Francisco Examiner, purchased by William Randolph Hearst. His talent for drawing and interest in Arabian horses dovetailed in 1893 at the Chicago Daily Herald when he studied and drew the Arabian horses exhibited at the World's Columbian Exposition. When Hearst acquired the New York Morning Journal in 1895, money was no object in his attempt to establish the Journal as a leading New York newspaper, and Hearst moved Davenport east in 1885 to be part of what is regarded as one of the greatest newspaper staffs ever assembled. Working with columnist Alfred Henry Lewis, Davenport created many cartoons in opposition to the 1896 Republican presidential candidate, former Ohio governor William McKinley, and Hanna, his campaign manager. McKinley was elected and Hanna elevated to the Senate; Davenport continued to draw his sharp cartoons during the 1900 presidential race, though McKinley was again victorious. (Full article...)

Adult and juvenile specimens, Muséum national d'Histoire naturelle, Paris; the juvenile could possibly also be from Kangaroo Island

The King Island emu (Dromaius novaehollandiae minor) is an extinct subspecies of emu that was endemic to King Island, in the Bass Strait between mainland Australia and Tasmania. Its closest relative may be the extinct Tasmanian emu (D. n. diemenensis), as they belonged to a single population until less than 14,000 years ago when Tasmania and King Island were still connected. The small size of the King Island emu may be an example of insular dwarfism. The King Island emu was the smallest of all known emus and had darker plumage than the mainland emu. It was black and brown and had naked blue skin on the neck, and its chicks were striped like those on the mainland. The subspecies was distinct from the likewise small and extinct Kangaroo Island emu (D. n. baudinianus) in a number of osteological details, including size. The behaviour of the King Island emu probably did not differ much from that of the mainland emu. The birds gathered in flocks to forage and during breeding time. They fed on berries, grass and seaweed. They ran swiftly and could defend themselves by kicking. The nest was shallow and consisted of dead leaves and moss. Seven to nine eggs were laid, which were incubated by both parents.

Europeans discovered the King Island emu in 1802 during early expeditions to the island, and most of what is known about the bird in life comes from an interview French naturalist François Péron conducted with a sealer there, as well as depictions by artist Charles Alexandre Lesueur. They had arrived on King Island in 1802 with Nicolas Baudin's expedition, and in 1804 several live and stuffed King and Kangaroo Island emus were sent to France. The two live King Island specimens were kept in the Jardin des Plantes, and the remains of these and the other birds are scattered throughout various museums in Europe today. The logbooks of the expedition did not specify from which island each captured bird originated, or even that they were taxonomically distinct, so their status remained unclear until more than a century later. Hunting pressure and fires started by early settlers on King Island likely drove the wild population to extinction by 1805. The captive specimens in Paris both died in 1822 and are believed to have been the last of their kind. (Full article...)

Persoonia lanceolata, commonly known as lance-leaf geebung, is a shrub native to New South Wales in eastern Australia. It reaches 3 m (10 ft) in height and has smooth grey bark and bright green foliage. Its small yellow flowers grow on racemes and appear in the austral summer and autumn (January to April), followed by green fleshy fruits (known as drupes) which ripen the following spring (September to October). Within the genus Persoonia, P. lanceolata belongs to the lanceolata group of 58 closely related species. It interbreeds with several other species found in its range.

The species is usually found in dry sclerophyll forest on sandstone-based nutrient-deficient soil. It has adapted to a fire-prone environment; plants lost in bushfires can regenerate through a ground-stored seed bank. Seedlings mostly germinate within two years of fires. Several species of native bee of the genus Leioproctus pollinate the flowers. Swamp wallabies are a main consumer of its fruit, and the seeds are spread in wallaby faeces. Its lifespan ranges from 25 to 60 years, though difficulties in propagation have seen low cultivation rates. (Full article...)

Title page of the 1859 edition

On the Origin of Species (or, more completely, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life) is a work of scientific literature by Charles Darwin that is considered to be the foundation of evolutionary biology; it was published on 24 November 1859. Darwin's book introduced the scientific theory that populations evolve over the course of generations through a process of natural selection. The book presented a body of evidence that the diversity of life arose by common descent through a branching pattern of evolution. Darwin included evidence that he had collected on the Beagle expedition in the 1830s and his subsequent findings from research, correspondence, and experimentation.

Various evolutionary ideas had already been proposed to explain new findings in biology. There was growing support for such ideas among dissident anatomists and the general public, but during the first half of the 19th century the English scientific establishment was closely tied to the Church of England, while science was part of natural theology. Ideas about the transmutation of species were controversial as they conflicted with the beliefs that species were unchanging parts of a designed hierarchy and that humans were unique, unrelated to other animals. The political and theological implications were intensely debated, but transmutation was not accepted by the scientific mainstream. (Full article...)

Two sheep on the shoreline of North Ronaldsay

The North Ronaldsay or Orkney is a breed of sheep from North Ronaldsay, the northernmost island of Orkney, off the north coast of Scotland. It belongs to the Northern European short-tailed sheep group of breeds, and has evolved without much cross-breeding with modern breeds. It is a smaller sheep than most, with the rams (males) horned and ewes (females) mostly hornless. It was formerly kept primarily for wool, but now the two largest flocks are feral, one on North Ronaldsay and another on the Orkney island of Auskerry. The Rare Breeds Survival Trust lists the breed as a priority on its 2021–2022 watchlist, and they are in danger of extinction, with fewer than 600 registered breeding females in the United Kingdom.

The semi-feral flock on North Ronaldsay is the original flock that evolved to subsist almost entirely on seaweed – they are one of few mammals to do this. They are confined to the foreshore by a 1.8 m (6 ft) drystane dyke, which completely encircles the island, forcing the sheep to evolve this unusual characteristic. The wall was built as kelping (the production of soda ash from seaweed) on the shore became uneconomical. Sheep were confined to the shore to protect the fields and crofts inside, and afterwards subsisted largely on seaweed. (Full article...)

Life drawing by Paul Jossigny, 1770s

Newton's parakeet (Psittacula exsul), also known as the Rodrigues parakeet or Rodrigues ring-necked parakeet, is an extinct species of parrot that was endemic to the Mascarene island of Rodrigues in the western Indian Ocean. Several of its features diverged from related species, indicating long-term isolation on Rodrigues and subsequent adaptation. The rose-ringed parakeet of the same genus is a close relative and probable ancestor. Newton's parakeet may itself have been ancestral to the endemic parakeets of nearby Mauritius and Réunion.

Around 40 centimetres (16 in) long, Newton's parakeet was roughly the size of a rose-ringed parakeet. Its plumage was mostly greyish or slate blue in colour, which is unusual in Psittacula, a genus containing mostly green species. The male had stronger colours than the female and possessed a reddish instead of black beak, but details of a mature male's appearance are uncertain; only one male specimen is known, and it is believed to be immature. Mature males might have possessed red patches on the wing like the related Alexandrine parakeet. Both sexes had a black collar running from the chin to the nape, but this was clearer in the male. The legs were grey and the iris yellow. Some 17th-century accounts indicate that some members of the species were green, which would suggest that both blue and green colour morphs occurred, but no definitive explanation exists for these reports. Little is known about its behaviour in life, but it may have fed on the nuts of the bois d'olive tree, along with leaves. It was very tame and was able to mimic speech. (Full article...)

At Little Tobago Island, Trinidad, and Tobago

The red-billed tropicbird (Phaethon aethereus) is a tropicbird, one of three closely related species of seabird of tropical oceans. Superficially resembling a tern in appearance, it has mostly white plumage with some black markings on the wings and back, a black mask and, as its common name suggests, a red bill. Most adults have tail streamers that are about two times their body length, with those in males being generally longer than those in females. The red-billed tropicbird itself has three subspecies recognized, including the nominate. The subspecies mesonauta is distinguished from the nominate by the rosy tinge of its fresh plumage, and the subspecies indicus can be differentiated by its smaller size, more restricted mask, and more orange bill. This species ranges across the tropical Atlantic, eastern Pacific, and Indian Oceans. The nominate is found in the southern Atlantic Ocean, the subspecies indicus in the waters off of the Middle East and in the Indian Ocean, and the subspecies mesonauta in the eastern portions of both the Atlantic and the Pacific Oceans and in the Caribbean. It was one of the many species described by Carl Linnaeus in his 1758 10th edition of Systema Naturae.

Nesting takes place in loose colonies, as they nest a scrape found on a cliff face that is easy to take off from. A single egg is laid and is incubated by both sexes for about six weeks. Whether the egg hatches or not can be influenced by pollution and weather, although the latter has a minimal effect on whether a chick fledges or not. After a chick fledges, the parents will usually stop visiting the nest and the chick will leave. Birds of all ages feed on fish and squid, catching them by diving from the air into the water. However, the red-billed tropicbird sometimes follows surface-feeding predators. The predators will drive the prey to the surface, which are then seized by the tropicbird. (Full article...)

Teleosts of different orders, painted by Castelnau, 1856 (left to right, top to bottom): Fistularia tabacaria (Syngnathiformes), Mylossoma duriventre (Characiformes), Mesonauta acora (Cichliformes), Corydoras splendens and Pseudacanthicus spinosus (Siluriformes), Acanthurus coeruleus (Acanthuriformes), Stegastes pictus (Incertae sedis, Pomacentridae)

Teleostei (/ˌtɛliˈɒstiaɪ/; Greek teleios "complete" + osteon "bone"), members of which are known as teleosts (/ˈtɛliɒsts, ˈtiːli-/), is, by far, the largest infraclass in the class Actinopterygii, the ray-finned fishes, containing 96% of all extant species of fish. Teleosts are arranged into about 40 orders and 448 families. Over 26,000 species have been described. Teleosts range from giant oarfish measuring 7.6 m (25 ft) or more, and ocean sunfish weighing over 2 t (2.0 long tons; 2.2 short tons), to the minute male anglerfish Photocorynus spiniceps, just 6.2 mm (0.24 in) long. Including not only torpedo-shaped fish built for speed, teleosts can be flattened vertically or horizontally, be elongated cylinders or take specialised shapes as in anglerfish and seahorses.

The difference between teleosts and other bony fish lies mainly in their jaw bones; teleosts have a movable premaxilla and corresponding modifications in the jaw musculature which make it possible for them to protrude their jaws outwards from the mouth. This is of great advantage, enabling them to grab prey and draw it into the mouth. In more derived teleosts, the enlarged premaxilla is the main tooth-bearing bone, and the maxilla, which is attached to the lower jaw, acts as a lever, pushing and pulling the premaxilla as the mouth is opened and closed. Other bones further back in the mouth serve to grind and swallow food. Another difference is that the upper and lower lobes of the tail (caudal) fin are about equal in size. The spine ends at the caudal peduncle, distinguishing this group from other fish in which the spine extends into the upper lobe of the tail fin. (Full article...)

Neptune is the eighth planet from the Sun and the farthest known planet in the Solar System. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times the mass of Earth, and slightly more massive than its near-twin Uranus. Neptune is denser and physically smaller than Uranus because its greater mass causes more gravitational compression of its atmosphere. Being composed primarily of gases and liquids, it has no well-defined solid surface. The planet orbits the Sun once every 164.8 years at an average distance of 30.1 astronomical units (4.5 billion kilometres; 2.8 billion miles). It is named after the Roman god of the sea and has the astronomical symbol , representing Neptune's trident. (Full article...)

The social history of viruses describes the influence of viruses and viral infections on human history. Epidemics caused by viruses began when human behaviour changed during the Neolithic period, around 12,000 years ago, when humans developed more densely populated agricultural communities. This allowed viruses to spread rapidly and subsequently to become endemic. Viruses of plants and livestock also increased, and as humans became dependent on agriculture and farming, diseases such as potyviruses of potatoes and rinderpest of cattle had devastating consequences.

Smallpox and measles viruses are among the oldest that infect humans. Having evolved from viruses that infected other animals, they first appeared in humans in Europe and North Africa thousands of years ago. The viruses were later carried to the New World by Europeans during the time of the Spanish Conquests, but the indigenous people had no natural resistance to the viruses and millions of them died during epidemics. Influenza pandemics have been recorded since 1580, and they have occurred with increasing frequency in subsequent centuries. The pandemic of 1918–19, in which 40–50 million died in less than a year, was one of the most devastating in history. (Full article...)

Drymoreomys is a rodent genus in the tribe Oryzomyini that lives in the Atlantic Forest of Brazil. The single species, D. albimaculatus, is known only from the states of São Paulo and Santa Catarina and was not named until 2011. It lives in the humid forest on the eastern slopes of the Serra do Mar and perhaps reproduces year-round. Although its range is relatively large and includes some protected areas, it is patchy and threatened, and the discoverers recommend that the animal be considered "Near Threatened" on the IUCN Red List. Within Oryzomyini, Drymoreomys appears to be most closely related to Eremoryzomys from the Andes of Peru, a biogeographically unusual relationship, in that the two populations are widely separated and each is adapted to an arid or a moist environment.

With a body mass of 44–64 g (1.6–2.3 oz), Drymoreomys is a medium-sized rodent with long fur that is orange to reddish-buff above and grayish with several white patches below. The pads on the hindfeet are very well developed and there is brown fur on the upper sides of the feet. The tail is brown above and below. The front part of the skull is relatively long and the ridges on the braincase are weak. The palate is short, with its back margin between the third molars. Several traits of the genitals are not seen in any other oryzomyine rodent. (Full article...)

Portrait of Kepler by an unknown artist in 1620

Johannes Kepler (/ˈkɛplər/; German: [joˈhanəs ˈkɛplɐ, -nɛs -] (listen); 27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best known for his laws of planetary motion, and his books Astronomia nova, Harmonice Mundi, and Epitome Astronomiae Copernicanae. These works also provided one of the foundations for Newton's theory of universal gravitation.

Kepler was a mathematics teacher at a seminary school in Graz, where he became an associate of Prince Hans Ulrich von Eggenberg. Later he became an assistant to the astronomer Tycho Brahe in Prague, and eventually the imperial mathematician to Emperor Rudolf II and his two successors Matthias and Ferdinand II. He also taught mathematics in Linz, and was an adviser to General Wallenstein.
Additionally, he did fundamental work in the field of optics, invented an improved version of the refracting (or Keplerian) telescope, and was mentioned in the telescopic discoveries of his contemporary Galileo Galilei. (Full article...)