Science and Medicine

Subcategories:
Clear

Entry Category: Science and Medicine - Starting with D

DeGray Dam and Lake

DeGray Dam, located about eight miles northwest of Arkadelphia (Clark County), impounds the 13,400-acre DeGray Lake on the Caddo River. It was built by the U.S. Army Corps of Engineers (USACE) for purposes of electricity generation and flood control, as well as establishing a drinking water supply for Arkadelphia, and is the first “pump back capable impoundment” in the Corps’s history. A reregulation dam forms a 400-acre impoundment below the main lake, providing a supply of water that can be pumped back into DeGray Lake during times of drought and used again for hydropower generation and to provide a steady flow of water on the Caddo River. The site where DeGray Dam stands had been considered for a dam since …

Dellinger, Samuel Claudius

Samuel Claudius Dellinger was curator of the University of Arkansas Museum in Fayetteville (Washington County) and head of the Department of Zoology for over thirty years. As curator, he built the museum’s archaeology collection into one of the best in the nation. In Dellinger’s view, the museum was, first and foremost, an educational resource for the people of Arkansas, and he worked to generate interest in it from the university community and the general public. Samuel Dellinger was born on January 14, 1892, in Iron Station (later Lincolntown), North Carolina, to Robert H. and Laura Loftin Dellinger. After graduating from high school, Dellinger attended Trinity College (later Duke University), where he was a varsity wrestler and swimmer. Dellinger earned his …

Derechos, Squall Lines, Downbursts/Microbursts, and “Rogue” Winds

While Arkansas makes national news far more often for its tornadoes, the state suffers its fair share of what are commonly known as straight-line winds. For example, on June 5, 2014, a weather event originating in Colorado crossed northeastern Arkansas, killing two people, derailing a train in Craighead County, and leaving thousands without power. A derecho (pronounced “deh-REY-cho”) is an event that consists of winds that create a swath of damage that extends for more than 240 miles, has minimal wind gusts of at least fifty-eight miles per hour (mph) for most of this swath, and includes multiple hurricane-force (seventy-five mph or greater) gusts. Derechos originate from what are commonly called “bow echoes,” named for their curved radar signature. About …

Dibrell, James Anthony, Jr.

James Anthony Dibrell Jr. was a founder of the University of Arkansas Medical Department (now the University of Arkansas for Medical Sciences—UAMS) and served as its second dean. As a practicing physician and dean of the medical school, Dibrell was responsible for many of the developments in medical education in Arkansas at the turn of the century. James Dibrell was born on August 20, 1846, near Van Buren (Crawford County). His father, James A. Dibrell Sr., was a prominent pioneer physician of the Van Buren area well known in state medical circles. The Civil War had taken a toll on the family finances, so Dibrell began his medical education by “reading” medicine with his father in the evenings and working …

Diphtheria

Diphtheria is a serious contagious disease caused by toxin-producing strains of the bacteria Corynebacterium diphtheriae. Typically occurring in childhood, diphtheria is transmitted from person to person through respiratory droplets or contaminated surfaces. The symptoms appear following an incubation period of two to five days and include fever, chills, sore throat, fatigue, and swollen lymph glands in the neck. The formation of an adherent, thick, grayish pseudomembrane in the throat distinguishes the disease. Respiratory diphtheria can be fatal due to either respiratory obstruction or heart and kidney failure. Cutaneous diphtheria is a skin infection that rarely causes serious systemic illness. Recovery does not confer lifelong immunity. In 400 BC, the ancient Greek physician Hippocrates provided an early description of diphtheria. It …

Diplurans

aka: Two-Pronged Bristletails
The primitive insects known as diplurans belong to the phylum Arthropoda, subphylum Hexapoda, class Insecta and order Diplura. They are considered to have three lineages: the Campodeoidea, Japygoidea, and Projapygoidea. These superfamilies are defined morphologically by three different types of cerci (paired appendages) found across all the dipluran families. There are ten families in this cosmopolitan order distributed from the tropics to the temperate zones. Diplurans belong to one of the four groups of Hexapoda, with other primitive apterygote insects, including springtails (Collembola) and coneheads (Protura). There are about 800 described species, of which around seventy (9%) occur in North America, twelve (2%) in the United Kingdom, and two (0.3%) in Australia. In 2016, species of diplurans were reported from …

Dipteran Parasites

aka: Parasitic Dipterans
aka: flies
aka: mosquitos
aka: gnats
The order Diptera belongs to the Phylum Arthropoda and Class Insecta. The order ranks number two among all insect orders—only behind beetles (Coleoptera)—with about 125,000 described species (there are an estimated 1,000,000 total species), many of which are considered parasitic or serve as vectors for diseases. There are two main groups (suborders): the Nematocera with seven infraorders and Brachycera with six infraorders. Dipterans—including the sixty species of mosquitoes that occur in Arkansas and Missouri—can be irritating to humans and harmful to livestock and other animals. A major repository of voucher specimens of dipterans in Arkansas is the Entomology Arthropod Museum at the University of Arkansas in Fayetteville (Washington County). It houses the largest research and reference collection of insects and …

Dipterans

aka: True Flies
The order Diptera belongs to the Phylum Arthropoda, Subphylum Labiata, Superclass Hexapoda, and Class Insecta. Among all insect orders, the order is number two in total number of species, ranked only behind beetles (Coleoptera), with about 125,000 described species (and an estimated 1,000,000 total species). They include house flies, blow flies, mosquitoes, gnats, black flies, midges, crane flies, horseflies, fruit flies, and others. Arkansas is home to many of these species. The first true fossil dipterans are known from the Middle Triassic Period (about 240 million years ago [mya]), and became more widespread during the Middle to Late Triassic. Although modern flowering plants did not appear until the Cretaceous (around 140 mya), the original dipterans may have had a different …

Disease during the Civil War

Disease was a major problem among the armies serving in Arkansas during the Civil War. Large numbers of men living in close confines made the spread of illness likely. As many as 700,000 members of the military across the country lost their lives during the war, and approximately two-thirds of them died from disease. Outbreaks of disease were common in the state even before the beginning of the war. In 1855, a yellow fever epidemic struck Helena (Phillips County), and minor outbreaks of other diseases such as cholera and typhoid were common. The lack of major centers of population and difficulty of travel, however, prevented many large-scale epidemics before the Civil War. The state had a number of doctors in …

Dodge, Eva Francette

Eva Francette Dodge was a pioneer physician, educator in obstetrics and gynecology, and advocate for maternal health care and sex education for young people in Arkansas and the United States. Her influence was felt worldwide through her work with the Pan American Medical Women’s Alliance (PAMWA) as an obstetrical consultant. Dodge was adamant in her belief that birth control was a right of women and that sex education was to be provided for all youth. Eva Dodge was born on July 24, 1896, to George Dodge and Winnie Worthen Dodge in New Hampton, New Hampshire. Her father was a physician who greatly influenced her choice of medicine as a career. She was the eldest of three daughters. Dodge graduated from …

Dog Heartworms

aka: Dirofilaria immitis
The canine heartworm (Dirofilaria immitis) is a filarial parasite that belongs to the Phylum Nematoda, Class Secertenea, Order Spirurida, and Family Onchocercidae. There are two subgenera: Dirofilaria and Nochtiella. This parasite is often found in wild and domestic canids throughout the world, especially in the United States where it is endemic from the East to the Midwest, the southeastern Atlantic seaboard, and the southern Gulf Coast. Transmission of the parasite occurs throughout the United States (even Alaska) and in the warmer regions of Canada. In the United States, the highest infection rates are found within 241 km (150 mi.) of the coast from Texas northeast to New Jersey, and along the Mississippi River Valley and its major tributaries. The parasite …

Drummond-Webb, Jonathan

Jonathan Drummond-Webb was the chief pediatric heart surgeon at Arkansas Children’s Hospital from 2001 to 2004. He brought the David Clark Heart Center into national prominence through his high success rate, averaging 600 surgeries per year with only a two percent mortality rate. He also performed the first-ever successful surgery using the DeBakey ventricular assist device (VAD), a miniature heart pump, in 2004. Jonathan Drummond-Webb was born in Johannesburg, South Africa, on August 29, 1959, toErrol Praine Drummond and Anne Drummond-Webb. He was first inspired to become a heart surgeon after Dr. Christiaan Barnard performed the world’s first successful human-to-human heart transplant, in Cape Town, South Africa. Drummond-Webb stated in an interview that when he learned of this, he was “amazed …

Duke, Charles Sumner

A trailblazing African-American architect and engineer, Charles Sumner Duke not only designed unique public structures, but he also fought for housing rights and educational opportunities for African Americans. His powerful legacy continues in the buildings he designed, as well as in the organization he formed to facilitate the development of engineering and technological skills in youth of color. Charles Sumner Duke was born in Selma, Alabama, on July 21, 1879. His father, Jesse Duke, was the editorial writer and publisher for a local newspaper, The Herald. His mother, Willie Black Duke, was from a family of established businessmen. It was a financially secure family, allowing Duke and his siblings to take advantage of opportunities that many others in the black …

DuVal, Elias Rector

In the late nineteenth century, physician Elias Rector DuVal (sometimes rendered Duval) was a leader in the drive to modernize medicine in Arkansas. In the 1870s, he cofounded the Arkansas State Medical Association (ASMA) and the Arkansas Medical Society (AMS). E. R. DuVal was born on August 13, 1836, in Fort Smith (Sebastian County) to William DuVal, who was a trader, and his wife, Harriet Tabitha Doddridge DuVal. The family included three sisters and two brothers. In 1835, DuVal’s sister Catherine DuVal married Elias Rector. Rector was a U.S. marshal for the Western District of Arkansas and Indian Territory and later served as superintendent of Indian Affairs. Educated in the local schools, DuVal graduated from Arkansas College in Fayetteville (Washington …