The riverine barrier model suggests that rivers play a significant role in separating widespread organisms into isolated populations. In this study, we used a comparative approach to investigate the phylogeography of 6 didelphid marsupial species in central Brazil. Specifically, we evaluate the role of the mid-Araguaia River in differentiating populations and estimate divergence time among line...

Previous studies have suggested that birds and mammals select materials needed for nest building based on their thermal or structural properties, although the amounts or properties of the materials used have been recorded for only a very small number of species. Some of the behaviours underlying the construction of nests can be indirectly determined by careful deconstruction of the structure an...

Nearly all the major Web search engines today use link analysis to improve their search results. That’s exciting news for linear algebraists because link analysis, the use of the Web’s hyperlink structure, is built from fundamentals of matrix theory. Link analysis and its underlying linear algebra have helped revolutionize Web search, so much so that the pre-link analysis search (before 1998) p...

Male pales weevils, Hylobius pales (Herbst), were sexually immature upon emergence from their pupal cells. During the first 2 wk of adult life the concentration of sperm bundles in the testes increased, and a lumen containing a granular material began to form in the accessory glands. Most individuals had active sperm when 2 wk old. Four-week-old males had a large concentration of sperm bundles,...

Adrenal glands of small smooth-tailed tree shrews (Dendrogale murina), four males and two females, caught and fixed in Thailand were observed macroscopically and histologically. They were located at the cranio-medial sides of the kidney. They were elongated in shape and consisted of a cortex and medulla. The cortex could be subdivided into three zones by the cell arrangement and the morphology ...

In 1837, Piorry, a French professor of medicine stated, "It is rather difficult to understand why the investigation of veins has been passed over almost in silence, while such a great diagnostic value has been attached to the investigation of arteries." Even today, our understanding of venous disease pales in comparison to our understanding of arterial disease. This is despite the fact that mil...