نتایج جستجو برای: cobble
تعداد نتایج: 285 فیلتر نتایج به سال:
Natural selection often promotes evolutionary innovation by coopting preexisting genes for new functions, and this process may be greatly facilitated by gene duplication. Here we report an example of cooptive convergence where paralogous members of the globin gene superfamily independently evolved a specialized O(2) transport function in the two deepest branches of the vertebrate family tree. S...
Corpus luteum formation is characterized by a period of extensive vascularization, as capillaries in the thecal layer of the collapsed follicle following ovulation invade the previously avascular granulosa layer. In order to study these processes in vitro we have developed an endothelial cell preparation from the specific microvasculature of the ovarian follicle. Follicular aspirates, obtained ...
The use of fish closures as a management tool to protect juvenile fish habitat and adult spawning grounds has become increasingly popular, although knowledge of the direct effects of marine closures on juvenile fish populations is limited. Given that monkfish landings account for a considerable percentage of the monetary value derived from the groundfish fishery in new England, investigating th...
--A stratified systematic sampling design was used to quantify the habitat relationships of the Del Norte salamander (Plethodon elongatus) in northwestern California. We sampled 57 sites, each within at least 5-7 ha of relatively homogeneous forest or post-forest habitat, where we measured 83 characteristics of the environment. Salamander sampling consisted of area-constrained sampling of 7 x 7...
Morphological differentiation in the ground beetles of the Nebria gregaria group, found on the Queen Charlotte Islands, has been used as support for the glacial refugium proposed for the northwest coast of North America. Two members of this species group, N. charlottae and N. louiseae, are restricted to cobble beaches in this archipelago. A third, N. haida, is found only in alpine regions of th...
There’s a medical student in the office today and we just saw a woman with pelvic inflammatory disease. We reviewed the guidelines for treatment and came to the catch — she can’t afford the treatment. Catches like this are common in my office, so off we go to the sample room to try and cobble together a reasonable alternative. I treat the working poor, refugees and immigrants. Many of these pat...
Employing an atomic force microscope (AFM) in conjunction with a quartz crystal microbalance, we have investigated how a high-frequency lateral oscillation of the substrate influences the imaging process of the AFM. It was found that the time-averaged deflection of the cantilever (both vertical and lateral) changed when the oscillation of the quartz resonator was turned on. The vertical-tip-sub...
A colonial tunicate belonging to the genus Didemnum has recently been found in many temperate coastal regions throughout the world, as well as large areas of Georges Bank in the NW Atlantic. It continues to spread rapidly and compete aggressively with native, hard substrate species (e.g., mussels, barnacles, bryozoans, other ascidians). In addition, it can form dense mats on deepwater cobble-gr...
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