The mammals of Angola

Scientific investigations on the mammals of Angola started over 150 years ago, but information remains scarce and scattered, with only one recent published account. Here we provide a synthesis of the mammals of Angola based on a thorough survey of primary and grey literature, as well as recent unpublished records. We present a short history of mammal research, and provide brief information on each species known to occur in the country. Particular attention is given to endemic and near endemic species. We also provide a zoogeographic outline and information on the conservation of Angolan mammals. We found confirmed records for 291 native species, most of which from the orders Rodentia (85), Chiroptera (73), Carnivora (39), and Cetartiodactyla (33). There is a large number of endemic and near endemic species, most of which are rodents or bats. The large diversity of species is favoured by the wide range of habitats with contrasting environmental conditions, while endemism tends to be associated with unique physiographic settings such as the Angolan Escarpment. The mammal fauna of Angola includes 2 Critically Endangered, 2 Endangered, 11 Vulnerable, and 14 Near-Threatened species at the global scale. There are also 12 data deficient species, most of which are endemics or near endemics to the countryinfo:eu-repo/semantics/publishedVersio

The fracture toughness of a ultrahigh carbon steel containing 1.5 wt% C

Thermomechanical processing of ultrahigh-carbon steels allows the attainment of spheroidized and pearlitic microstructures that show very different mechanical properties. Spheroidized microstructures are formed by proeutectoid and eutectoid carbide particles embedded in a ferrite matrix. The mean proeutectoid carbide particle size is larger than the mean eutectoid carbide particle size and is practically invariable with austenitizing temperature below 850 °C. Pearlitic microstructures exhibit prior austenite grain sizes and pearlite colony sizes which increase and interlamellar spacings which decrease as the austenitizing temperature increases above 850 °C. A proeutectoid carbide size distribution that remains basically constant with austenitizing temperature is also observed in these microstructures. Plane-strain fracture toughness of spheroidized and pearlitic UHCS-1.5C materials do not vary significantly with austenitizing temperature, being the average fracture toughness of about 40 MPa m1/2 and 30 MPa m1/2, respectively. The constancy of fracture toughness with austenitizing temperature of the spheroidized microstructures is attributed to the constancy of the mean proeutectoid and eutectoid carbide size. Austenite grain size, pearlite colony size, interlamellar spacing and undissolved proeutectoid carbide size are evaluated for the influence of fracture toughness associated with pearlitic microstructures. It is found that proeutectoid carbide is the microstructural parameter that controls fracture toughness of pearlitic microstructures. Austenite grain size, pearlite colony size and interlamellar spacing are considered to have a minor influence.Peer reviewe

Facilitating the social behaviour of bull elephants in zoos

From Crossref journal articles via Jisc Publications RouterHistory: epub 2019-10-10Article version: VoRPublication status: Publishe

Devastating Decline of Forest Elephants in Central Africa.

African forest elephants– taxonomically and functionally unique–are being poached at accelerating rates, but we lack range-wide information on the repercussions. Analysis of the largest survey dataset ever assembled for forest elephants (80 foot-surveys; covering 13,000 km; 91,600 person-days of fieldwork) revealed that population size declined by ca. 62% between 2002–2011, and the taxon lost 30% of its geographical range. The population is now less than 10% of its potential size, occupying less than 25% of its potential range. High human population density, hunting intensity, absence of law enforcement, poor governance, and proximity to expanding infrastructure are the strongest predictors of decline. To save the remaining African forest elephants, illegal poaching for ivory and encroachment into core elephant habitat must be stopped. In addition, the international demand for ivory, which fuels illegal trade, must be dramatically reduced