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  • 1
    Publication Date: 2011-04-23
    Description: Shallow Radar soundings from the Mars Reconnaissance Orbiter reveal a buried deposit of carbon dioxide (CO(2)) ice within the south polar layered deposits of Mars with a volume of 9500 to 12,500 cubic kilometers, about 30 times that previously estimated for the south pole residual cap. The deposit occurs within a stratigraphic unit that is uniquely marked by collapse features and other evidence of interior CO(2) volatile release. If released into the atmosphere at times of high obliquity, the CO(2) reservoir would increase the atmospheric mass by up to 80%, leading to more frequent and intense dust storms and to more regions where liquid water could persist without boiling.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Phillips, Roger J -- Davis, Brian J -- Tanaka, Kenneth L -- Byrne, Shane -- Mellon, Michael T -- Putzig, Nathaniel E -- Haberle, Robert M -- Kahre, Melinda A -- Campbell, Bruce A -- Carter, Lynn M -- Smith, Isaac B -- Holt, John W -- Smrekar, Suzanne E -- Nunes, Daniel C -- Plaut, Jeffrey J -- Egan, Anthony F -- Titus, Timothy N -- Seu, Roberto -- New York, N.Y. -- Science. 2011 May 13;332(6031):838-41. doi: 10.1126/science.1203091. Epub 2011 Apr 21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Planetary Science Directorate, Southwest Research Institute, Boulder, CO 80302, USA. roger@boulder.swri.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21512003" target="_blank"〉PubMed〈/a〉
    Keywords: Atmosphere ; Carbon Dioxide ; Cold Temperature ; *Dry Ice ; Extraterrestrial Environment ; Ice ; *Mars ; Water
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 2
    ISSN: 1432-1106
    Keywords: Frontal cortex ; Prelimbic cortex ; Mediodorsal thalamus ; Septum ; Delayed alternation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Rats were trained preoperatively on contingently reinforced delayed alternation in a T-maze. Then different matched groups of rats received lesions in the prelimbic cortex, mediodorsal thalamus, posterodorsal septum (aimed at transecting the precommissural fornix), and control operations (no brain lesions). Following a 2-week recovery period the rats were retested in the T-maze for retention of delayed alternation. Control rats were unaffected by the control operations and the testing hiatus of the recovery period. Rats with lesions in the prelimbic cortex performed at chance levels on the first postoperative session as did rats with posterodorsal septal lesions, but both groups recovered with continued experience, i.e., they could relearn the task. Rats with lesions in mediodorsal thalamus were only slightly affected by the lesions, The results suggest that a restricted field in the medial pregenual cortex, the prelimbic area, is critically involved in T-maze alternation. However, the data also suggest that a major subcortical source of afferents to prelimbic cortex, the mediodorsal nucleus of the thalamus, is not crucial for retention of delayed alternation. Impairment in retention of contingently reinforced T-maze delayed alternation following interference with septo-hippocampal circuitry is consistent with data previously reported.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0428
    Keywords: Pancreatic islets ; substantia nigra ; rat ; autonomic nervous system ; neural control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of substantia nigra lesions on the volume densities of islet cells and on the content of insulin and glucagon in the pancreas were examined using five groups of age-matched, Sprague-Dawley rats. Two groups received bilateral substantia nigra lesions using intrathecal injections of either a low (6 μg/hemisphere) or a high (12 μg/hemisphere) dose of 6-hydroxydopamine. Rats given sham lesions served as controls for the effects of the neurotoxic drug. These three groups, plus a fourth consisting of unoperated controls, were provided with a high-fat diet to minimize lesion-induced alterations of food intake and body weight. Eleven weeks after lesion placement, tissue was collected from all animals for the assessment of islet cell volume densities and the pancreatic content of insulin and glucagon. Plasma samples also were obtained to determine the levels of glucose, insulin, and glucagon. Data from those animals were compared with that obtained from a fifth group, termed “pre-lesion controls”, sacrificed at the beginning of the experiment. Linear-scan morphometry documented an increase of B-cell volume density in the pancreas of non-lesioned rats over the 11-week period (p〈0.05). However, the volume density of B cells in the pancreas of lesioned animals did not increase compared with that of pre-lesion controls. In terms of A or D cells, no significant differences of volume density were found between the five groups. Compared with that of the pre-lesion controls, pancreatic insulin and glucagon content increased in the lesioned and neurally-intact animals. However, the molar ratio of those hormones in the pancreas of lesioned rats remained similar to that of pre-lesion controls. The current findings suggest that the substantia nigra is an important autonomic area involved in controlling islet growth and development, and possibly islet function as well.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-7446
    Keywords: anti-inflammatory therapy ; Escherichia coli ; goats ; mastitis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Coliform mastitis in dairy cattle frequently results in systemic disease with occasional deaths in association with endotoxic shock. Systemic anti-inflammatory therapy has been used to alter the course of endotoxic shock in severe cases. Use of anti-inflammatory therapy has been questioned on the basis that such treatment may compromise immune function and decrease clearance of bacteria from infected mammary glands. The purpose of this investigation was to determine whether anti-inflammatory therapy influenced bacterial clearance following intramammary challenge of lactating goats with Escherichia coli. Standardized quantities of a pathogenic coliform culture were infused through the teat canal into one half of the mammary gland in 18 goat does. The does were then randomly assigned to receive one of three intravenous treatments: saline (controls), one dose of steroid (dexamethasone), or two doses of a non-steroidal anti-inflammatory agent (flunixin meglumine). The clinical signs, milk production, complete blood counts, serum clinical chemistry values, milk bacterial cultures and milk somatic cell concentrations were monitored sequentially. Goats treated with anti-inflammatory agents exhibited some improvement in clinical response to challenge with E. coli (e.g. rectal temperature, degree of appetite suppression) as compared to saline controls. There were no significant differences between treatments in the degree of inflammation present in the mammary glands or supramammary lymph nodes examined at necropsy. The most important finding was that anti-inflammatory therapy did not adversely influence the clearance of E. coli from challenged glands.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 42 (1977), S. 315-320 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Along the California coast there are three intertidal species of the genus Gibbonsia (G. elegans, G. metzi, G. montereyensis). These species have distinct but overlapping distributions. Collections were made seasonally from three areas. Each collection was divided into two groups — a critical thermal maximum and minimum were determined for one group and the other group was tested after a 3 week acclimation period. The three species showed genetically different adaptation abilities and these were correlated with species differences in latitudinal distributions. The species that experiences the widest seasonal temperature range proved capable of anticipatory adjustment to temperature while the two experiencing small seasonal changes showed only reactive adjustments. the species with the widest distribution showed the greatest ability to adapt to temperature extremes. After 1 week acclimation all three species demonstrated different mechanisms for heat and cold adaptation.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four geographic populations of the painted greenling Oxylebius pictus, a small cryptic reef fish of the western coast of North America, were examined for biochemical evidence of genetic differentiation. Painted greenlings in Puget Sound and those in central and southern California are similar by Nei's genetic identity (I=0.966 to 0.995); Fowever, other observations argue for genetic differentiation among the 4 populations. First, there are geographic differences in allelic frequencies at two loci (Est-3 and Pgm), with a geographic cline exhibited at the latter locus. Second, and most significant, two assayable loci are uniquely present in pairs of populations below Point Conception (G3pdh-3) and above Point Conception (Idh-3), respectively. Larval dispersal patterns are inferred from breeding times for the painted greenling and on patterns of currents off the western coast of North America. We believe that gene flow in this species is less across Point Conception than between Puget Sound, Washington, and Monterey, California, on the basis of these genetic data and the patterns of dispersal.
    Type of Medium: Electronic Resource
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  • 8
    Publication Date: 2018-03-06
    Description: Maintenance of biodiversity in a rapidly changing climate will depend on the efficacy of evolutionary rescue, whereby population declines due to abrupt environmental change are reversed by shifts in genetically driven adaptive traits. However, a lack of traits known to be under direct selection by anthropogenic climate change has limited the incorporation of evolutionary processes into global conservation efforts. In 21 vertebrate species, some individuals undergo a seasonal color molt from summer brown to winter white as camouflage against snow, whereas other individuals remain brown. Seasonal snow duration is decreasing globally, and fitness is lower for winter white animals on snowless backgrounds. Based on 2713 georeferenced samples of known winter coat color—from eight species across trophic levels—we identify environmentally driven clinal gradients in winter coat color, including polymorphic zones where winter brown and white morphs co-occur. These polymorphic zones, underrepresented by existing global protected area networks, indicate hot spots for evolutionary rescue in a changing climate.
    Keywords: Evolution
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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