Entries - Entry Category: Science and Medicine - Starting with P

Paddlefish belong to the family Polyodontidae and order Acipensiformes. There are six known species—four are extinct (three from western North America, one from China) and known only from fossil remains, while two extant species include the paddlefish (Polyodon spathula), which is native to the Mississippi River basin in the United States, and the gigantic critically endangered Chinese paddlefish (Psephurus gladius) endemic to the Yangtze River Basin in China, where they lived primarily in the broad-surfaced main stem rivers and shoal zones along the East China Sea. Paddlefish are basal Chondrostean ray-finned fish; they are archaic and have been referred to as “primitive fish” because they have evolved with few unique morphological changes since the earliest fossil records of the late …

Two, possibly three, huge rocks from outer space put the Arkansas town of Paragould (Greene County) into the history and science books early in 1930. What is now known as the Paragould Meteorite was, at that time, the largest meteorite to ever have been seen falling and then recovered. A belt of rocks known as the asteroid belt, left over from the formation of the solar system, orbits the sun mainly between the orbits of planets Mars and Jupiter. Due to the gravity of nearby Jupiter, some of these rocks can stray inward and cross Earth’s orbit, even striking it. At 4:08 a.m. on February 17, 1930, the orbit of one of these rocks crossed Earth’s orbit, and two fields …

The Subphylum Crustacea (Phylum Arthropoda) represents a diverse group of animals with members within several classes and orders, including the Amphipoda, Branchiura, Cirripedia, Copepoda, Isopoda, and Tantulocarida. (The Pentastomida, composed of parasites, are sometimes included in this subphylum and sometimes considered a separate phylum.) There are two classes with parasites: the Maxillopoda and Malacostraca. The majority of crustaceans are aquatic, living in either marine environments or fresh water, but a few groups have adapted to a terrestrial existence, such as some species of crabs and woodlice. Most crustaceans move about independently and live a free existence, although some are parasitic (about 30,000 named species) and live attached as ectoparasites to their hosts, including fish, sea, and whale lice, as well …

The passenger pigeon (Ectopistes migratorius) was a North American bird species in the order Columbiformes (pigeons and doves) that became extinct in the early twentieth century. The fate of the passenger pigeon serves as a graphic lesson in the misuse of natural resources, as the species went from an almost indescribable abundance to extinction in only a few decades. The decline came primarily as a result of relentless persecution of its breeding colonies by market hunters, largely for meat, with no (or ineffectual) regulation that might have maintained a stable population. The passenger pigeon had the same general body shape as the common and familiar mourning dove (Zenaida macroura) but was larger and somewhat more colorful, with areas of slate-blue …

Pauropods belong to the Phylum Arthropoda, Subphylum Labiata, Superclass Myriapoda, and Class Pauropoda. They are small, pale, millipede-like arthropods. There are about 830 species in twelve families worldwide, and they live under rocks in moist soil, leaf mold, and woodland litter. Only a single species, Eurypauropus spinosus, has been reported from Arkansas, but there are likely more that would be uncovered with further research. The only known fossil pauropod is Eopauropus balticus, a prehistoric species known from mid-Eocene Baltic amber (40 to 35 million years ago). Because pauropods are normally soil-dwelling, their presence in amber (fossilized tree sap) is unusual, and they are the rarest known animals in Baltic amber. They appear to be an old group closely related to …

Pellagra is a form of malnutrition caused by a severe deficiency of niacin (also known as nicotinic acid or vitamin B3) in the diet. The disease affected thousands of Arkansans and other Southerners in the late nineteenth and early twentieth centuries. Symptoms of pellagra can include lack of energy, outbreaks of red splotches on the skin, diarrhea, and—in extreme cases—depression, dementia, and even death. Pellagra is not contagious, and the condition can be reversed. The lethargic appearance of pellagra victims was also a symptom of two other diseases widely found in the South at the time, hookworm and malaria. These three contributed to the false stereotype of Southerners at this time as lazy. Pellagra was first recognized as a disease in 1762 …

The phylum Pentastomida (some consider it a class) includes four orders, seven families, and about 144 species, including eight extinct species from the Paleozoic Era. They are wormlike obligate parasites, meaning that they cannot complete their life cycle without a host. As adults, they inhabit the respiratory tract (lungs and nasal passages) of vertebrates. Four species are known from intermediate host insects (three coprophagus cockroaches and one coleopteran). In addition, fishes are common intermediate hosts for pentastomes occurring in crocodilians and piscivorous chelonians, and rarely for some species of snakes. Definitive hosts include amphibians (few hosts) but mainly reptiles (lizards, snakes, freshwater turtles, and crocodilians), the latter making up about seventy percent of hosts. The most common genera of reptilian …

The Percidae is a family containing three subfamilies and approximately 250 species within eleven genera of perciform fishes found mostly in freshwater and brackish waters of the Northern Hemisphere. Most are found in the Nearctic realm. It is one of the largest families in North America, making up about one-fifth of all fish biota, only outnumbered by the Cyprinidae. There are also some Palearctic (Eurasian) species in the genera Gymnocephalus (four species), Percarina (two species), Romanichthys (single species), and Zingel (four species). The family includes the perches and their relatives, with some well-known species such as the ruffe, sauger, walleye, and three species of perch. However, much smaller fishes restricted to North America known as darters are also an integral …

Pertussis or “whooping cough” is an acute infectious disease caused by the bacteria Bordetella pertussis. Person-to-person transmission occurs through respiratory droplets. Following an incubation period of seven to fourteen days, pertussis progresses through the catarrhal, paroxysmal, and convalescent stages. Cold-like symptoms—including a runny nose, sneezing, a mild cough, and a low-grade fever—characterize the catarrhal stage. The paroxysmal stage begins one or two weeks later and lasts for up to eight weeks. Patients suffer from numerous rapid bursts of productive coughing followed by a long, inspiratory whoop, which is the origin of the disease’s common name. Young infants may exhibit breathing difficulties instead of whooping. Coughing spasms produce vomiting and cyanosis. Gradual recovery characterizes the convalescent stage. Neither vaccination nor recovery …

Pillstrom Tongs were invented by Lawrence G. Pillstrom MD for the safe capture of snakes for scientific research. The company eventually began shipping these unique, safe herpetological tools all over the world. They are used by zoos, animal control agencies, specialty animal handlers, collectors, and others. The company expanded upon the line of original snake tongs and modified them to be used for hunting frogs, pruning trees, cooking outdoors, picking up aluminum cans, and more. In 1953, as a young student at what is now the University of Arkansas for Medical Sciences (UAMS) in Little Rock (Pulaski County), Pillstrom began some early studies and medical research of snake venom and its effects. As a key part of his doctoral work, …

The pirate perch (Aphredoderus sayanus) belongs to the order Aphredoderiformes (or by some sources, Percopsiformes) and family Aphredoderidae. There are two subspecies, A. s. sayanus and A. s. gibbosus. It is the only living member of the family and ranges from the Atlantic and Gulf slopes from Michigan, Wisconsin, Minnesota, and New York south to the Gulf of Mexico and west to the Brazos River drainage, Texas. In Arkansas, A. sayanus occurs throughout the Coastal Plain physiographic region extending westward into the central areas of the state. It is quite rare in the Ozark uplands, and there are no records from the northwestern part of the state. The Aphredoderidae contains one fossil genus, Trichophanes, with possibly two of three valid …

Margaret Pittman was known worldwide for her pioneering research into the microbiology and immunology of infectious diseases. Her work in developing a vaccine for whooping cough remains the scientific basis (with later improvements) for protecting the children of Arkansas and the world from this potentially deadly disease. Margaret Pittman was born near Prairie Grove (Washington County) on January 20, 1901, to James Pittman, a country doctor, and Virginia Alice McCormick. In 1909, the family moved to the village of Cincinnati (Washington County), where Margaret and her sister sometimes helped with administering anesthesia and vaccinating patients in their father’s practice. After his early death, Virginia Pittman took her children—Margaret, Mary Helen, and James—to Conway (Faulkner County), where she did dressmaking and …

There are at least seven species of planarians found in Arkansas, on land and in water. Planarians belong to the superphylum Lophotrochozoa, phylum Platyhelminthes, subphylum Catenulidea, class Rhabditophora (some consider the artificial grouping Turbellaria), order Tricladida, suborder Paludicola, and families Dugesiidae, Kenkiidae, Planariidae, and Dendrocoelidae. These flatworms are often simply referred to as triclads or triclad worms. Currently, the order Tricladida is split into three suborders, including the marine forms (Maricola); those found mostly in freshwater habitats of caves, although at least one species occurs in surface waters (Cavernicola); and land planarians/freshwater triclads (Continenticola). Scientists have argued about the systematics of platyhelminths for many years, and with the advent of molecular approaches (18S and 28S ribosomal DNA sequences), older classification …

Through education, advocacy, and direct services, Planned Parenthood seeks to ensure healthy sexuality, family health, and access to high-quality sexual and reproductive healthcare. The topic of reproductive education and healthcare has long been a source for debate both nationally and in Arkansas. At the height of the Depression, Little Rock (Pulaski County) activist Hilda Cornish was convinced that the ability to limit family size could be crucial to a family’s financial survival. In February 1931, Cornish established the Little Rock Birth Control Clinic, the first such service in Arkansas. Services were provided at a minimal fee for any married woman whose family made less than $75 per month. Establishment of this clinic was met with public resistance; one woman wrote, …

Not all mushrooms are appropriate for human consumption, although there is no broad group of poisonous fungi, as many different families contain toxins. Although some toxic species do not kill humans outright and might only cause gastrointestinal (GI) distress such as nausea and vomiting, others can be debilitating and even fatal. They include species that affect the central nervous system (CNS) and induce mild hallucinations, while a small number of taxa contain various toxins that are fatal to humans. There are many types of mushrooms in Arkansas, and the Arkansas Mycological Society (AMS) helps educate its members in the morphological similarities and differences between the harmless and the poisonous. The number of poisonous (fatal) mushrooms is relatively small, perhaps just …

The poliovirus terrorized the United States for many years, and Arkansas was no exception. Infection with the virus either went unnoticed or caused poliomyelitis, commonly called polio, which resulted in paralysis that sometimes ended in death but more often left its victims permanently handicapped. As the disease often affected children, it was also called infantile paralysis. While the large urban centers of the country dealt with polio epidemics early in the twentieth century, Arkansas had only a few intermittent cases. The Arkansas Gazette, however, reported frequently on the disease, keeping its readers informed of efforts to combat, cure, and curtail its devastating effects in other areas. After the first significant numbers were reported in the state, Arkansans reacted to the …

Presbyterian Village is a residential care facility located in Little Rock (Pulaski County). At the time of its opening in 1965, it represented a new approach to healthcare for senior citizens in the area. Rather than focusing on one aspect of senior care, such as independent living or nursing home care, Presbyterian Village was designed to provide progressive care that could evolve with a resident’s changing healthcare needs. As a result, Presbyterian Village provided independent apartment living, assisted living, and nursing home care all in one facility, remaining the only healthcare facility of its type in the area until the mid-1970s. It was listed on the National Register of Historic Places on September 8, 2020. Presbyterian Village was the brainchild …

In 2016, a pro-ISIL group hacked the website of the Arkansas Library Association (ArLA) and released the membership directory to other ISIL supporters as a scare tactic, although the breach had few consequences for the organization. In June 2014, the terrorist organization known as the Islamic State of Iraq and the Levant (ISIL), also called Islamic State (IS) or the Islamic State of Iraq and al-Sham (ISIS), declared a global caliphate (Islamic state ruled by a religious leader). By March 2015, ISIL had established its rule over sizeable portions of Syria and Iraq and benefitted from sympathetic supporters around the world. Starting in 2015, pro-ISIL supporters began waging indiscriminate cyberattacks against various Western websites and databases. Hackers specifically targeted websites …

Proturans belong to the Phylum Euarthropoda, Class Entognatha, and Class Protura. The Protura constitute a taxon of hexapods that were previously thought to be insects and now are considered as a class on their own. Proturans are cosmopolitan in distribution (except for both polar regions and snow zones of mountains) with more than 800 described species belonging to three distinct orders (Acerentomata, Eosentomata, and Sinentomata) and seven families (Acerentomidae, Antelientomidae Eosentomidae, Fujientomidae, Hesperentomidae, Protentomidae, and Sinentomidae). As of 2019, seventy-six genera are known worldwide, with nearly 300 species contained within the single cosmopolitan genus, Eosentomon. There are about twenty-six species in North America, though there is no exact number of species reported, to date, from Arkansas. However, four species of …

Pseudoscorpions belong to the phylum Arthropoda, class Arachnida, order Pseudoscorpionida, and two suborders (Epiocheirata and Iocheirata). There are more than 3,300 species within about 430 genera, with more described as new species regularly. They are cosmopolitan in distribution and occur in a variety of habitats from temperate to cold regions from Northern Ontario, Canada, and above the timberline in the Rocky Mountains of Wyoming in the United States to the karst system of the Jenolan Caves of New South Wales, Australia. However, pseudoscorpions are most dense with diverse populations in the tropics and subtropics, where they can be found on island territories such as the Canary Islands, where about twenty-five endemic species have been reported. There are also two endemic …

Public health is a dynamic, interdisciplinary field with the goal of improving and maintaining the health and well-being of communities through education, the promotion of healthy behaviors and lifestyles, the creation of health-related government policy, and research on disease and injury prevention. In Arkansas, the field of public health has been active since territorial days, when infectious diseases such as malaria plagued the area. In the early days, efforts to improve sanitation, prevent the spread of disease, and treat the health problems of the public in Arkansas centered on diseases—particularly malaria, hookworm, polio, yellow fever, typhoid, and tuberculosis. In modern times, public health campaigns in Arkansas have moved toward a focus on chronic health problems such as obesity and diabetes. …

The Pulaski County Medical Society (PCMS), founded in 1866, is Arkansas’s largest and one of the state’s oldest county medical organizations for regular physicians (meaning those within the medical mainstream.) (Although sources identify the PCMS as the “first medical organization chartered by the state of Arkansas,” an earlier organization, known as the Crawford County Medical Society, was established in the early 1840s.) The PCMS supports physicians and promotes public health. In nineteenth-century America, regular physicians formed professional organizations to advocate for themselves. In 1866, a group of Little Rock (Pulaski County) physicians, including Philo Oliver Hooper and Roscoe G. Jennings, formed the Little Rock and Pulaski County Medical Society. The PCMS, whose members were required to be American Medical Association …

Albert Homer Purdue was the ex officio state geologist from 1907 to 1912. He published many works on the geology of both Arkansas and Tennessee. Purdue was a renowned geologist and taught at Arkansas Industrial University, which is now the University of Arkansas (UA) in Fayetteville. Albert Purdue was born on March 29, 1861, on a farm near Yankeetown, Indiana, to Samuel Leroy and Phoebe (Priest) Purdue. Albert was the second oldest of eight children and spent his youth working on the family farm, receiving only minimal formal education. At the age of twenty, however, he entered the Indiana State Normal School (later Indiana State University) in Terre Haute. He received his diploma on June 8, 1888. Until 1896, Purdue …