158 research outputs found
Density of large predators on commercial farmland in Ghanzi, Botswana
Accurate estimates of predator densities are important
for the conservation management of large
predator populations. Predator densities outside of
protected areas are often understudied and management
decisions are based on assumptions of predator
numbers. This study conducted three spoor
surveys on commercial farmland in Botswana to
estimate large predator densities. Brown hyaenas
(Hyaena brunnea) were found to occur evenly across
both cattle and game farms at higher densities than
previously assumed. Cheetahs (Acinonyx jubatus)
and leopards (Panthera pardus) were more commonly
located on game ranches, at or below population
density assumptions. This study demonstrated the
importance but difficulties of conducting predator
surveys on farmland, where study animals are often
at risk of persecution by landowners, due to the
perceived or real threat predators may pose to livestock
and stocked game.Cheetah
Conservation, Chester Zoo and Rufford small grants.http://www.sawma.co.za/am201
Water management on claypan soils in the midwest
Irrigation scheduling with soil moisture monitoring devices provided the most efficient use of water on claypan soils. Corn was found to be particularly responsive to both drainage and irrigation with average
yield increases of 80 bushels per acre over the seven year period of the
experiment. Consequently, water management was found to be an important aspect of corn production. Hybrid selection was found to be important to maximize the benefits of water management. Soybeans were found to be less responsive to irrigation than corn. Also, soybeans were found to be more responsive to drainage during the growing season than corn. Soybean variety selection was found to be important to prevent lodging when irrigation was used. Surface drainage is an important practice in water management but irrigation was found to be necessary to prevent yield reduction particularly with corn, when top soil was removed during the construction needed for surface drainage.U.S. Geological SurveyU.S. Department of the InteriorOpe
The colour of paternity: extra-pair paternity in the wild Gouldian finch does not appear to be driven by genetic incompatibility between morphs.
In socially monogamous species, individuals can use extra-pair paternity and offspring sex allocation as adaptive strategies to ameliorate costs of genetic incompatibility with their partner. Previous studies on domesticated Gouldian finches (Erythrura gouldiae) demonstrated a genetic incompatibility between head colour morphs, the effects of which are more severe in female offspring. Domesticated females use differential sex allocation, and extra-pair paternity with males of compatible head colour, to reduce fitness costs associated with incompatibility in mixed-morph pairings. However, laboratory studies are an oversimplification of the complex ecological factors experienced in the wild, and may only reflect the biology of a domesticated species. This study aimed to examine the patterns of parentage and sex-ratio bias with respect to colour pairing combinations in a wild population of the Gouldian finch. We utilized a novel PCR assay that allowed us to genotype the morph of offspring before the morph phenotype develops, and to explore bias in morph paternity and selection at the nest. Contrary to previous findings in the laboratory, we found no effect of pairing combinations on patterns of extra-pair paternity, offspring sex ratio, or selection on morphs in nestlings. In the wild, the effect of morph incompatibility is likely much smaller, or absent, than was observed in the domesticated birds. Furthermore, the previously studied domesticated population is genetically differentiated from the wild population, consistent with the effects of domestication. It is possible that the domestication process fostered the emergence (or enhancement) of incompatibility between colour morphs previously demonstrated in the laboratory. This article is protected by copyright. All rights reserved
Pre-release hunting training and post-release monitoring are key components in the rehabilitation of orphaned large felids
The rehabilitation of orphaned animals is commonly practiced but rarely scientifically
documented. The behavioural development before release (e.g. regarding hunting skills) is
particularly important for ensuring animals are self-sustaining after release. We document
the rehabilitation and release of three confiscated cheetah (Acinonyx jubatus) cubs and one
leopard (Panthera pardus) cub, which were taken from the wild in Botswana. The animals
were raised with minimal human contact and the development of their hunting skills was
observed and assisted by limited pre-release training. After release, all animals were
monitored and data showed they successfully hunted, with behavioural patterns similar to
wild conspecifics. All established stable home ranges at the release site.Home ranges of the
cheetahs ranged from 44 to 121 km2, travelling primarily during the early morning and
evening, ranging from4.5 to 9.4 km/day. While the leopard survived and probably reproduced
within a stable home range (449km2), all three cheetahs were shot within 7 months of release.
Therefore, although orphaned large felids can successfully hunt after release using appropriate rehabilitation techniques, they face the same human–carnivore conflicts of their wild
counterparts. Our study demonstrates the indispensable but commonly neglected need for post-release monitoring in wildlife rehabilitation.http://www.sawma.co.za
Unpacking the complex nature of cooperative interactions: case studies of Israeli–Palestinian environmental cooperation in the greater Bethlehem area
Regulation of a rat VL30 element in human breast cancer cells in hypoxia and anoxia: role of HIF-1
Novel approaches to cancer gene therapy currently exploit tumour hypoxia to achieve transcriptional targeting using oxygen-regulated enhancer elements called hypoxia response elements. The activity of such elements in hypoxic cells is directly dependent on upregulation of the hypoxia-inducible transcription factor-1 However tumours also contain areas of anoxia, which may be considered a more tumour-selective transcriptional stimulus than hypoxia for targeting gene therapy to tumours. Another element, from the rat virus-like retrotransposon, VL30 (termed the ‘secondary anoxia response element’) has been reported to be more highly inducible in rat fibroblasts under anoxia than hypoxia. To investigate anoxia as a potential transcriptional target in human tumours, we have examined secondary anoxia response element inducibility in two human breast cancer cell lines, MCF-7 and T47D, under anoxia, hypoxia and normoxia. In both cell types, the trimerised secondary anoxia response element showed greater inducibility in anoxia than hypoxia (1% and 0.5% O2). The anoxic response of the secondary anoxia response element was shown to be dependent on hypoxia-inducible transcription factor-1 and the presence of a hypoxia-inducible transcription binding site consensus (5′-ACGTG-3′). Mutational analysis demonstrated that the base immediately 5′ to this modulates the anoxic/hypoxic induction of the secondary anoxia response element, such that TACGTG>GACGTG>>CACGTG. A similar correlation was found for erythropoietin, phosphoglycerate kinase 1, and aldolase hypoxia response elements, which contain these respective 5′ flanking bases
Identification of Radiopure Titanium for the LZ Dark Matter Experiment and Future Rare Event Searches
The LUX-ZEPLIN (LZ) experiment will search for dark matter particle
interactions with a detector containing a total of 10 tonnes of liquid xenon
within a double-vessel cryostat. The large mass and proximity of the cryostat
to the active detector volume demand the use of material with extremely low
intrinsic radioactivity. We report on the radioassay campaign conducted to
identify suitable metals, the determination of factors limiting radiopure
production, and the selection of titanium for construction of the LZ cryostat
and other detector components. This titanium has been measured with activities
of U~1.6~mBq/kg, U~0.09~mBq/kg,
Th~~mBq/kg, Th~~mBq/kg, K~0.54~mBq/kg, and Co~0.02~mBq/kg (68\% CL).
Such low intrinsic activities, which are some of the lowest ever reported for
titanium, enable its use for future dark matter and other rare event searches.
Monte Carlo simulations have been performed to assess the expected background
contribution from the LZ cryostat with this radioactivity. In 1,000 days of
WIMP search exposure of a 5.6-tonne fiducial mass, the cryostat will contribute
only a mean background of (stat)(sys) counts.Comment: 13 pages, 3 figures, accepted for publication in Astroparticle
Physic
Simulations of events for the LUX-ZEPLIN (LZ) dark matter experiment
The LUX-ZEPLIN dark matter search aims to achieve a sensitivity to the WIMP-nucleon spin-independent cross-section down to (1–2)×10−12 pb at a WIMP mass of 40 GeV/c2. This paper describes the simulations framework that, along with radioactivity measurements, was used to support this projection, and also to provide mock data for validating reconstruction and analysis software. Of particular note are the event generators, which allow us to model the background radiation, and the detector response physics used in the production of raw signals, which can be converted into digitized waveforms similar to data from the operational detector. Inclusion of the detector response allows us to process simulated data using the same analysis routines as developed to process the experimental data
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Projected WIMP sensitivity of the LUX-ZEPLIN dark matter experiment
LUX-ZEPLIN (LZ) is a next-generation dark matter direct detection experiment that will operate 4850 feet underground at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. Using a two-phase xenon detector with an active mass of 7 tonnes, LZ will search primarily for low-energy interactions with weakly interacting massive particles (WIMPs), which are hypothesized to make up the dark matter in our galactic halo. In this paper, the projected WIMP sensitivity of LZ is presented based on the latest background estimates and simulations of the detector. For a 1000 live day run using a 5.6-tonne fiducial mass, LZ is projected to exclude at 90% confidence level spin-independent WIMP-nucleon cross sections above 1.4×10-48 cm2 for a 40 GeV/c2 mass WIMP. Additionally, a 5σ discovery potential is projected, reaching cross sections below the exclusion limits of recent experiments. For spin-dependent WIMP-neutron(-proton) scattering, a sensitivity of 2.3×10-43 cm2 (7.1×10-42 cm2) for a 40 GeV/c2 mass WIMP is expected. With underground installation well underway, LZ is on track for commissioning at SURF in 2020
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