636 research outputs found

    Ecological Distribution of Small Mammals in the De Long Mountains of Northwestern Alaska

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    The ecological distribution of small mammals (<200 g) was studied in the foothill tundra of the De Long Mountains in northwestern Alaska. Three species of shrews and five species of microtine rodents were trapped on 15 live-trapping grids during 1978 and 1979. Emphasis was placed on the three most abundant microtine species (Clethrionomys rutilus, Microtus oeconomus and M. gregalis). During late summer up to six species of small mammals were captured per habitat type which ranged from wet meadow through mesic shrubland to dry ridges. Following snowmelt most habitats contained only a single species and some contained none. Only four habitat types were continuously occupied by small mammals during both summers. Species diversity was variable among habitats. Most species of small mammals were captured on eight or fewer of the 15 trapping grids. Only Clethrionomys rutilus was captured on all grids. The number of habitats occupied by Clethrionomys rutilus increased from 4 to 14 as population densities increased. The number of habitats occupied by the other species seemed to be independent of population density. Average population densities for the microtines were low (<15/ha) and, for each species, varied according to habitat type. Only Clethrionomys rutilus populations demonstrated marked intra-annual fluctuations (3/ha to 37/ha).Key words: rodents, habitat, Alaska, populations, Clethrionomys rutilus, Micro oeconomus, Microtu gregalisMots clés: rongeurs, habitat, Alaska, populations, Clethrionomys rutilus, Microtus oeconomus, M. gregali

    Research Issues Surrounding Holocaust Survivors: Adaptability and Aging

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    The thesis of this article is that, in spite of a large body of literature on the subject, a significant need exists for sociological research on the long-term consequences of the trauma experienced by survivors of Nazi concentration camps. Most of what is known about the adjustment of Holocaust survivors is based upon limited case histories of survivors who sought psychiatric aid, or requested assistance in qualifying for indemnification payments from the German government. The social and psychological dynamics of successful adjustment to life after the traumatic Holocaust experience by the majority of survivors has largely been ignored. Reasons for this oversight are discussed, and several areas of further research are suggested

    Hantavirus Outbreaks in Deer Mice in Montana May Be Predictable Based on Mouse Population Dynamics

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    Sin Nombre hantavirus (SNV) is a rodent-borne virus that causes hantavirus pulmonary syndrome in humans, which has a 37% mortality rate. There is no vaccine or cure, therefore the best strategy is to prevent spillover from rodent hosts. Understanding the ecological drivers of infection in rodent populations can lead to better predictive models of disease dynamics in the reservoir and consequent risk to humans. Using an epidemiological model parameterized and cross-validated using a long term dataset from Montana, I show how environmental variation and fluctuating mouse density affects hantavirus prevalence. I provide evidence for a critical host density necessary to sustain transmission and show how there can be long delays between peaks in density and subsequent peaks in infection prevalence. The lengths of these delays vary with density but are predictable. This means that outbreaks may sometimes be predictable many months in advance. These same principles should also apply to many other disease systems in wildlife with fluctuating populations, and may help predict and mitigate wildlife disease

    Grazing Effects on Deer Mice with Implications to Human Exposure to Sin Nombre Virus

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    We examined the effects of grazing on deer mouse (Peromyscus maniculatus) movements into buildings using passive integrated transponder (PIT) technology and small simulated buildings located on 0.6-ha treatment (grazing) and control (no grazing) plots. Twelve experimental 9-day trials were conducted over the course of the study. During these trials, mouse movements into buildings were monitored during three time periods (each 3 days in length). In the treatment plots these time periods corresponded to pre-grazing, grazing, and post grazing by horses. The number of individual deer mice entering buildings over time decreased in both the grazed and control plots during the 9 days of each experiment. The number of entrances per/individual among the pre-grazing, grazing and post grazing periods was different between control and treated plots for both males and females. The distribution of entrances/individual among the three periods differed between males and females in both grazed and control plots. The habitat modification caused by grazing appeared to reduce deer mouse activity (entrances/individual) in buildings but does not affect the number of mice entering buildings. Reducing vegetative cover by grazing or mowing may not affect the number of mice investigating small structures but grazing creates different activity patterns in the structures for neighboring deer mice

    Effect of Rock Cover on Small Mammal Abundance in a Montana Grassland

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    We examined the influence of rock cover, as an indicator of presumable retreat site availability on the abundance of deer mice (Peromyscus maniculatus) and prevalence of Sin Nombre virus (SNV) using long-term live trapping and habitat data from three live trapping grids and a shortterm (three month), spatially replicated study across three slopes in Cascade County, Montana. In our long-term study, we found that deer mice were more abundant at a live-trapping grid with greater rock cover, than two grids with less rock cover. There was a non-significant trend (P = 0.053) for deer mice to be more abundant in rocky sites in the short term study. In the long-term study, average SNV antibody prevalence among deer mice was slightly greater (5.0 vs. 3.5 % on average) at the live trapping grid with more rock cover, than the grid with less rock cover. We were unable to demonstrate differences in SNV antibody prevalence among treatments in the short-term study. Further studies are needed to elucidate the multiple determinants of deer mouse abundance and SNV prevalence in grassland ecosystem and other habitat types

    Stratospheric General Circulation with Chemistry Model (SGCCM)

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    In the past two years constituent transport and chemistry experiments have been performed using both simple single constituent models and more complex reservoir species models. Winds for these experiments have been taken from the data assimilation effort, Stratospheric Data Analysis System (STRATAN)

    Removing Deer Mice from Buildings and the Risk for Human Exposure to Sin Nombre Virus

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    Trapping and removing deer mice from ranch buildings resulted in an increased number of mice, including Sin Nombre virus antibody–positive mice, entering ranch buildings. Mouse removal without mouse proofing will not reduce and may even increase human exposure to Sin Nombre hantavirus

    The Atmospheric Effects of Stratospheric Aircraft: a First Program Report

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    Studies have indicated that, with sufficient technology development, high speed civil transport aircraft could be economically competitive with long haul subsonic aircraft. However, uncertainty about atmospheric pollution, along with community noise and sonic boom, continues to be a major concern; and this is addressed in the planned 6 yr HSRP begun in 1990. Building on NASA's research in atmospheric science and emissions reduction, the AESA studies particularly emphasizing stratospheric ozone effects. Because it will not be possible to directly measure the impact of an HSCT aircraft fleet on the atmosphere, the only means of assessment will be prediction. The process of establishing credibility for the predicted effects will likely be complex and involve continued model development and testing against climatological patterns. Lab simulation of heterogeneous chemistry and other effects will continue to be used to improve the current models

    Satellite observation and mapping of wintertime ozone variability in the lower stratosphere

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    Comparison is made between 30 mbar ozone fields that are generated by a transport chemistry model utilizing the winds from the Goddard Space Flight Center stratospheric data assimilation system (STRATAN), observations from the LIMS instrument on Nimbus-7, and the ozone fields that result from 'flying a mathematical simulation of LIMS observations through the transport chemistry model ozone fields. The modeled ozone fields were found to resemble the LIMS observations, but the model fields show much more temporal and spatial structure than do the LIMS observations. The 'satellite mapped' model results resemble the LIMS observations much more closely. These results are very consistent with the earlier discussions of satellite space-time sampling by Salby

    The Adirondack Chronology

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    The Adirondack Chronology is intended to be a useful resource for researchers and others interested in the Adirondacks and Adirondack history.https://digitalworks.union.edu/arlpublications/1000/thumbnail.jp
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