481 research outputs found
Effects of temporary captivity on ranging behaviour in urban red foxes (Vulpes vulpes)
Temporary removal of wild animals from a resident territory has the potential to markedly impact subsequent ranging behaviour, and may negatively affect post-release welfare and survival. Admission of sick or injured wildlife into temporary captivity (termed ‘rehabilitation’) is a common practice in the UK. However, post-release monitoring of rehabilitated animals is unusual or restricted to recording survival rates over limited time periods. As part of a wider study of urban fox behaviour, we employed an experimental approach to compare the ranging behaviour of seven rehabilitated and 13 wild-caught ‘control’ urban red foxes using GPS tracking. Foxes were tracked over a two-year period for an average of 48 nights, and seasonal and sex-related effects were controlled for via inclusion in statistical models. Three of the five movement parameters we investigated were irregular for the rehabilitated animals, relative to controls. These were: reduced likelihood of establishing a stable home range (42.9/57.1% of rehabilitated foxes versus 84.6% of controls); larger home ranges (Kruskal Wallis test, χ2 = 7.517, df = 1, p < 0.01); and further distance travelled from release point, as measured by overlap between initial and final home ranges (Linear regression, F1,12 = 4.755, df = 1, P < 0.05). Females moved greater distances than males overall, and foxes from both groups travelled further in spring, and delayed home range establishment in summer. However, these results were skewed by the movements of two apparently cooperatively breeding wild-caught vixens. Our data provide evidence of territorial displacement of rehabilitated foxes on release. We discuss the welfare implications of this finding
Changes in microphytobenthos fluorescence over a tidal cycle: implications for sampling designs
Intertidal microphytobenthos (MPB) are important primary producers and provide food for herbivores in soft sediments and on rocky shores. Methods of measuring MPB biomass that do not depend on the time of collection relative to the time of day or tidal conditions are important in any studies that need to compare temporal or spatial variation, effects of abiotic factors or activity of grazers. Pulse amplitude modulated (PAM) fluorometry is often used to estimate biomass of MPB because it is a rapid, non-destructive method, but it is not known how measures of fluorescence are altered by changing conditions during a period of low tide. We investigated this experimentally using in situ changes in minimal fluorescence (F) on a rocky shore and on an estuarine mudflat around Sydney (Australia), during low tides. On rocky shores, the time when samples are taken during low tide had little direct influence on measures of fluorescence as long as the substratum is dry. Wetness from wave-splash, seepage from rock pools, run-off, rainfall, etc., had large consequences for any comparisons. On soft sediments, fluorescence was decreased if the sediment dried out, as happens during low-spring tides on particularly hot and dry days. Surface water affected the response of PAM and therefore measurements used to estimate MPB, emphasising the need for care to ensure that representative sampling is done during low tide
The CRESST Dark Matter Search
We present first competitive results on WIMP dark matter using the
phonon-light-detection technique. A particularly strong limit for WIMPs with
coherent scattering results from selecting a region of the phonon-light plane
corresponding to tungsten recoils. The observed count rate in the neutron band
is compatible with the rate expected from neutron background. CRESST is
presently being upgraded with a 66 channel SQUID readout system, a neutron
shield and a muon veto system. This results in a significant improvement in
sensitivity.Comment: 6 pages, 3 figures, to be published in the proceedings of the 5th
International Workshop on the Identification and Detection of Dark Matter IDM
2004, Edinburgh, Sept. 2004, World Scientifi
Do Red Foxes (Vulpes vulpes) Increase the Detectability of Scent Marks by Selecting Highly Conspicuous Substrates?
Detection of the Natural Alpha Decay of Tungsten
The natural alpha decay of 180W has been unambiguously detected for the first
time. The alpha peak is found in a (gamma,beta and neutron)-free background
spectrum. This has been achieved by the simultaneous measurement of phonon and
light signals with the CRESST cryogenic detectors. A half-life of T1/2 = (1.8
+- 0.2) x 10^18 y and an energy release of Q = (2516.4 +- 1.1 (stat.) +- 1.2
(sys.)) keV have been measured. New limits are also set on the half-lives of
the other naturally occurring tungsten isotopes.Comment: Submitted to Physical Review C Revised versio
Adenosine triphosphate is co-secreted with glucagon-like peptide-1 to modulate intestinal enterocytes and afferent neurons.
Enteroendocrine cells are specialised sensory cells located in the intestinal epithelium and generate signals in response to food ingestion. Whilst traditionally considered hormone-producing cells, there is evidence that they also initiate activity in the afferent vagus nerve and thereby signal directly to the brainstem. We investigate whether enteroendocrine L-cells, well known for their production of the incretin hormone glucagon-like peptide-1 (GLP-1), also release other neuro-transmitters/modulators. We demonstrate regulated ATP release by ATP measurements in cell supernatants and by using sniffer patches that generate electrical currents upon ATP exposure. Employing purinergic receptor antagonists, we demonstrate that evoked ATP release from L-cells triggers electrical responses in neighbouring enterocytes through P2Y2 and nodose ganglion neurones in co-cultures through P2X2/3-receptors. We conclude that L-cells co-secrete ATP together with GLP-1 and PYY, and that ATP acts as an additional signal triggering vagal activation and potentially synergising with the actions of locally elevated peptide hormone concentrations.Wellcome Trust joint investigator award (106262/Z/14/Z and 106263/Z/14/Z); MRC programme within the Metabolic Diseases Unit (MRC_MC_UU_12012/3); MRC Metabolic Diseases Unit [MRC_MC_UU_12012/5] ; Wellcome Trust Strategic Award [100574/Z/12/Z
Status of the CRESST Dark Matter Search
The CRESST experiment aims for a detection of dark matter in the form of
WIMPs. These particles are expected to scatter elastically off the nuclei of a
target material, thereby depositing energy on the recoiling nucleus. CRESST
uses scintillating CaWO4 crystals as such a target. The energy deposited by an
interacting particle is primarily converted to phonons which are detected by
transition edge sensors. In addition, a small fraction of the interaction
energy is emitted from the crystals in the form of scintillation light which is
measured in coincidence with the phonon signal by a separate cryogenic light
detector for each target crystal. The ratio of light to phonon energy permits
the discrimination between the nuclear recoils expected from WIMPs and events
from radioactive backgrounds which primarily lead to electron recoils. CRESST
has shown the success of this method in a commissioning run in 2007 and, since
then, further investigated possibilities for an even better suppression of
backgrounds. Here, we report on a new class of background events observed in
the course of this work. The consequences of this observation are discussed and
we present the current status of the experiment.Comment: Proceedings of the 13th International Workshop on Low Temperature
Detectors, 4 pages, 3 figure
Composite CaWO4 Detectors for the CRESST-II Experiment
CRESST-II, standing for Cryogenic Rare Events Search with Superconducting
Thermometers phase II, is an experiment searching for Dark Matter. In the LNGS
facility in Gran Sasso, Italy, a cryogenic detector setup is operated in order
to detect WIMPs by elastic scattering off nuclei, generating phononic lattice
excitations and scintillation light. The thermometers used in the experiment
consist of a tungsten thin-film structure evaporated onto the CaWO4 absorber
crystal. The process of evaporation causes a decrease in the scintillation
light output. This, together with the need of a big-scale detector production
for the upcoming EURECA experiment lead to investigations for producing
thermometers on smaller crystals which are glued onto the absorber crystal. In
our Run 31 we tested composite detectors for the first time in the Gran Sasso
setup. They seem to produce higher light yields as hoped and could provide an
additional time based discrimination mechanism for low light yield clamp
events.Comment: Proceedings of the Thirteenth International Workshop on Low
Temperature Detectors 4 pages, 9 figure
- …