Yersinia pestisYersinia pestis (Y. pestis; formerly Pasteurella pestis) is a gram-negative, non-motile, coccobacillus bacterium without spores that is related to both Yersinia enterocolitica and Yersinia pseudotuberculosis, the pathogen from which Y. pestis evolved and responsible for the Far East scarlet-like fever. It is a facultative anaerobic organism that can infect humans via the Oriental rat flea (Xenopsylla cheopis). It causes the disease plague, which caused the Plague of Justinian and the Black Death, the deadliest pandemic in recorded history.
Prairie dogPrairie dogs (genus Cynomys) are herbivorous burrowing ground squirrels native to the grasslands of North America. Within the genus are five species: black-tailed, white-tailed, Gunnison's, Utah, and Mexican prairie dogs. In Mexico, prairie dogs are found primarily in the northern states, which lie at the southern end of the Great Plains: northeastern Sonora, north and northeastern Chihuahua, northern Coahuila, northern Nuevo León, and northern Tamaulipas.
American PrairieAmerican Prairie is a prairie-based nature reserve in Central Montana, United States, on a mixed grass prairie ecosystem with migration corridors and native wildlife. This wildlife conservation area is being developed as a private project of the American Prairie Foundation (APF). This independent non-profit organization aims to include over through a combination of both private and public lands. American Prairie provides public access to its land for all types of outdoor recreation including hiking, mountain biking, hunting, and fishing.
Disease vectorIn epidemiology, a disease vector is any living agent that carries and transmits an infectious pathogen to another living organism; agents regarded as vectors are organisms, such as parasites or microbes. The first major discovery of a disease vector came from Ronald Ross in 1897, who discovered the malaria pathogen when he dissected a mosquito. Arthropods form a major group of pathogen vectors with mosquitoes, flies, sand flies, lice, fleas, ticks, and mites transmitting a huge number of pathogens.
ZoonosisA zoonosis (zoʊˈɒnəsɪs,_ˌzoʊəˈnoʊsɪs; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a bacterium, virus, parasite or prion) that can jump from a non-human (usually a vertebrate) to a human and vice versa. Major modern diseases such as Ebola virus disease and salmonellosis are zoonoses. HIV was a zoonotic disease transmitted to humans in the early part of the 20th century, though it has now evolved into a separate human-only disease.
PathogenIn biology, a pathogen (πάθος, pathos "suffering", "passion" and -γενής, -genēs "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term pathogen came into use in the 1880s. Typically, the term pathogen is used to describe an infectious microorganism or agent, such as a virus, bacterium, protozoan, prion, viroid, or fungus. Small animals, such as helminths and insects, can also cause or transmit disease.
Percolation thresholdThe percolation threshold is a mathematical concept in percolation theory that describes the formation of long-range connectivity in random systems. Below the threshold a giant connected component does not exist; while above it, there exists a giant component of the order of system size. In engineering and coffee making, percolation represents the flow of fluids through porous media, but in the mathematics and physics worlds it generally refers to simplified lattice models of random systems or networks (graphs), and the nature of the connectivity in them.
Percolation theoryIn statistical physics and mathematics, percolation theory describes the behavior of a network when nodes or links are added. This is a geometric type of phase transition, since at a critical fraction of addition the network of small, disconnected clusters merge into significantly larger connected, so-called spanning clusters. The applications of percolation theory to materials science and in many other disciplines are discussed here and in the articles Network theory and Percolation (cognitive psychology).
Plague (disease)Plague is an infectious disease caused by the bacterium Yersinia pestis. Symptoms include fever, weakness and headache. Usually this begins one to seven days after exposure. There are three forms of plague, each affecting a different part of the body and causing associated symptoms. Pneumonic plague infects the lungs, causing shortness of breath, coughing and chest pain; bubonic plague affects the lymph nodes, making them swell; and septicemic plague infects the blood and can cause tissues to turn black and die.
GrasslandA grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur naturally on all continents except Antarctica and are found in most ecoregions of the Earth. Furthermore, grasslands are one of the largest biomes on earth and dominate the landscape worldwide. There are different types of grasslands: natural grasslands, semi-natural grasslands, and agricultural grasslands.
