222 resultados para White-footed mouse
Resumo:
Multilayer samples of white architectural paint potentially have very high evidential value in forensic casework, because the probability that two unrelated samples will have the same sequence of layers is extremely low. However, discrimination between the different layers using optical microscopy is often difficult or impossible. Here, lateral scanning Raman spectroscopy has been used to chemically map the cross-sections of multilayer white paint chips. It was found that the spectra did allow the different layers to be delineated on the basis of their spectral features. The boundaries between different layers were not as sharp as expected, with transitions occurring over length scales of > 20 µm, even with laser spot diameters <4 µm. However, the blurring of the boundaries was not so large as to prevent recording and identification of spectra from each of the layers in the samples. This method clearly provides excellent discrimination between different multilayer white paint samples and can readily be incorporated into existing procedures for examination of paint transfer evidence.
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Recent evidence suggests that bats can detect the geomagnetic field, but the way in which this is used by them for navigation to a home roost remains unresolved. The geomagnetic field may be used by animals both to indicate direction and to locate position. In birds, directional information appears to be derived from an interaction of the magnetic field with either the sun or the stars, with some evidence suggesting that sunset/sunrise provides the primary directional reference by which a magnetic compass is calibrated daily. We demonstrate that homing greater mouse-eared bats (Myotis myotis) calibrate a magnetic compass with sunset cues by testing their homing response after exposure to an altered magnetic field at and after sunset. Magnetic manipulation at sunset resulted in a counterclockwise shift in orientation compared with controls, consistent with sunset calibration of the magnetic field, whereas magnetic manipulation after sunset resulted in no change in orientation. Unlike in birds, however, the pattern of polarization was not necessary for the calibration. For animals that occupy ecological niches where the sunset is rarely observed, this is a surprising finding. Yet it may indicate the primacy of the sun as an absolute geographical reference not only for birds but also within other vertebrate taxa.
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This review considers the ethical and technical problems currently associated with employing mouse bioassays for marine-toxin analysis and the challenges and the difficulties that alternative methods must overcome before being deemed applicable for implementation into a regulatory monitoring regime. We discuss proposed alternative methods, classified as functional, immunological and analytical, for well-established European toxins as well as emerging toxins in European waters, highlighting their advantages and disadvantages. We also consider emerging tools and technologies for future toxin analysis.
Resumo:
A single founder mutation resulting in a Ser163Arg substitution in the C1QTNF5 gene product causes autosomal dominant late-onset retinal macular degeneration (L-ORMD) in humans, which has clinical and pathological features resembling age-related macular degeneration. We generated and characterised a mouse
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1. Skeletal remains of greater white-toothed shrew Crocidura russula were recovered from barn owl Tyto alba and kestrel Falco tinnunculus pellets collected at 15 locations in Counties Tipperary and Limerick in Ireland in September 2007 and March 2008. Seven greater white-toothed shrews were trapped at four locations in Tipperary in March 2008. This is the first Irish record of C. russula and compelling evidence that the species is established in Ireland.
Resumo:
1. The population characteristics and distribution of wood mice Apodemus sylvaticus (L.) were investigated along field margins of farmland dominated by grass production. 2. Turnover, sex ratio, breeding season, spatial density dependence and density dependence in reproductive activity indicated that the population ecology of A. sylvaticus is consistent in different habitats in the same geographical region. 3. Spatial variation in the abundance of A.sylvaticus was related negatively to percentage of land under pasture and distance from woodland and positively related to variables associated with food supply and cover. 4. Variation in numbers of overwintered mice at the start of the breeding season was related more closely to breeding opportunity than to environmental factors. This was particularly so in males. 5. The association of overwintered male and female A. sylvaticus remained evident in the later half of the breeding season. Young males and females of the year, however, were distributed more with respect to physical and biological features than towards adults or reproductive opportunity. 6. A. sylvaticus is an important species of field margins, even where these are poorly developed and agriculture is pastoral rather than arable. Further studies of this species in a wider range of agricultural systems are desirable.
Resumo:
1. This paper examines the interaction between the wood mouse, Apodemus sylvaticus L., and the intestinal nematode, Heligmosomoides polygyrus Dujardin, using data collected at Tollymore Park Forest, Co. Down, Northern Ireland, between November 1978 and July 1981.
Resumo:
(1) The abundance and dispersion of a population of Apodemus sylvaticus was investigated with respect to tree seed availability and vegetative structure over three harvests.
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Variation in the diet of wood mice, Apodemus sylvaticus, was investigated in two contrasting habitats, deciduous and coniferous woodland, over 26 months and in 10 additional sites trapped during winter. Stomach contents were categorized as seed, fruit, green plant, root and animal material. Diet was evaluated using the percentage occurrence of each food type. Age and sex differences in diet occurred infrequently. Seed predominated throughout but was especially prevalent in autumn and winter. There was a peak in the incidence of animal material in the spring and early summer. Animal food was generally more frequent in mice caught in conifer plantations than in deciduous woodland during the longer-term study. Further, mice from the additional coniferous habitats had greater percentage occurrence of animal food than those from the additional deciduous sites. There was a negative, non-linear association between relative population size and diet in these winter samples. This suggests that spatial variation in numbers of A. sylvaticus is dictated by food availability and density is locally food limited.