1,088 research outputs found
The diet of the Tasmanian Devil, Sarcophilus harrisii, as determined from analysis of scat and stomach contents
Knowledge of the diets of carnivores is an essential precursor to understanding their role as predators in ecosystems. To date, understanding of the diet of Tasmanian Devils, Sarcophilus harrisii, is limited and based upon largely qualitative descriptions. We examined the diets of Tasmanian Devils at six sites by identifying undigested hair, bone and feathers found in their scats. These sites range across different habitat types in coastal and inland Tasmania, and encompass devil populations that are known as both free of the Devil Facial Tumour Disease (DFTD) and populations that are infected by the disease. Tasmanian Devil scats at coastal sites (n=27) contained ten species of mammal, as well as birds, fish and insects. Scats collected from inland sites (n= 17) were comprised of six mammalian species, birds and invertebrates. The most common food items were birds, Common Brushtail and Ringtail possums (Trichosurus vulpecula and Pseudocheirus
peregrinus respectively), Tasmanian Pademelons (Thylogale billardierii) and Bennett's Wallabies (Macropus ruftgriseus). O fall the scats, 61% contained only one food group, 32% contained two groups, 4% contained three food items and only one scat (2%) contained four food groups. We supplement this information with stomach contents from road-killed devils, and compare our results with those of previous studies, with a view to furthering our understanding ofthe ecology ofthe threatened Tasmanian Devil. Such information will be important for the management of wild and captive devil populations, particularly in light of DFTD
Trapping and relocating seals from salmonid fish farms in Tasmania, 1990-2000: was it a success?
In an effort to reduce the impact of seals on fish farms, the trapping and relocation of seals at Tasmanian salmonid farms began in 1990. To the end of May 2000,353 identified individual seals had been trapped in 672 capture events. Most were non-breeding male Australian fur seals (Arctocephalus pusillus doriftrus). The number of seals captured increased (from four in 1990 ro a peak of 164 in 1998) with the size and extent of the farms, and an increase in salmon production from 55 tonnes in 1986/87 to almost 10000 tonnes in 1999/2000.
Of 586 capture events 52% were of seals that had been captured more than once. When seals are recaptured following trapping and relocation, this occurs on average 25 days after capture. Capture-mark-recapture calculations show that many seals in the vicinity of fish farms are not 'trappable', suggesting that trapping is only effective for certain individuals. Some individuals are recaptured many times, reflecting the predisposition of some individuals to be captured ('trap-happy'). Interaction is seasonal, with most seals trapped during winter, between May and September. The assessment of trends in capture rates is problematic, due to the lack of capture effort information from the farms. A further confounding factor has been the change in management practice both between farms and over time, as the use of predator nets has become more widespread. Two seals trapped at fish farms and fitted with satellite transmitters before relocation have
either not returned to the farm or returned to the vicinity of farms and not interacted with them, although on one occasion the individual was trapped. The effectiveness of the relocation program as a management tool to reduce seal interactions cannot be quantified from the relocation data per se, but relocation does not stop seals interacting with farms
Observations of mortality of fur seals between 1998 and 2005 in Tasmania, Australia
Because of their often close relationship with the human environment, the deaths of marine mammals are often documented, particularly if
there are links to anthropogenic influences. Between 1998 and 2005 a total of 504 dead Australian Fur Seals, Arctocephalus pusillus doriferus, and New Zealand Fur Seals, Arctocephalus forsteri, were reported in Tasmanian waters. Ninety individuals (18%) were dependent unweaned pups that had been displaced from their natal colonies. Of the 209 adult or subadult seals for which the cause of death could be ascertained,anthropogenic activities were identified as being responsible for the deaths of 172 individuals (82%), with 112 (53%) associated with fish farms. Most fish farm-related deaths occurred during the winter when adult and subadult seals were away from breeding colonies and seal numbers are highest around farms. The next most common cause of death was from firearms (41 individuals - 20%). Death of adults and subadults by natural causes accounted for 37 animals, or 18% of all deaths for which the cause was identified. Excluding pups, most seals were identified as Australian (80%) or New Zealand fur seals (3%). The remainder (17%) were identified as fur seals but not to species. Males were most common (58%), with only 6% identified as females; the sex of 36% could not be determined. Of the males, 106 (26%) were adults and 98 (24%) were subadults or juveniles
Blind Normalization of Speech From Different Channels
We show how to construct a channel-independent representation of speech that
has propagated through a noisy reverberant channel. This is done by blindly
rescaling the cepstral time series by a non-linear function, with the form of
this scale function being determined by previously encountered cepstra from
that channel. The rescaled form of the time series is an invariant property of
it in the following sense: it is unaffected if the time series is transformed
by any time-independent invertible distortion. Because a linear channel with
stationary noise and impulse response transforms cepstra in this way, the new
technique can be used to remove the channel dependence of a cepstral time
series. In experiments, the method achieved greater channel-independence than
cepstral mean normalization, and it was comparable to the combination of
cepstral mean normalization and spectral subtraction, despite the fact that no
measurements of channel noise or reverberations were required (unlike spectral
subtraction).Comment: 25 pages, 7 figure
Ground state correlations and structure of odd spherical nuclei
It is well known that the Pauli principle plays a substantial role at low
energies because the phonon operators are not ideal boson operators.
Calculating the exact commutators between the quasiparticle and phonon
operators one can take into account the Pauli principle corrections. Besides
the ground state correlations due to the quasiparticle interaction in the
ground state influence the single particle fragmentation as well. In this
paper, we generalize the basic QPM equations to account for both mentioned
effects. As an illustration of our approach, calculations on the structure of
the low-lying states in Ba have been performed.Comment: 12 pages, 1 figur
Low Energy States of : Elements on the Doubly-Magic Nature of Ni
Excited levels were attributed to Ga for the first time
which were fed in the -decay of its mother nucleus Zn produced in
the fission of U using the ISOL technique. We show that the structure
of this nucleus is consistent with that of the less exotic proton-deficient
N=50 isotones within the assumption of strong proton Z=28 and neutron N=50
effective shell effects.Comment: 4 pages, REVTeX 4, 5 figures (eps format
The Mineralogical and Chemical Case for Habitability at Yellowknife Bay, Gale Crater, Mars
Sediments of the Yellowknife Bay formation (Gale crater) include the Sheepbed member, a mudstone cut by light-toned veins. Two drill samples, John Klein and Cumberland, were collected and analyzed by the CheMin XRD/XRF instrument and the Sample Analysis at Mars (SAM) evolved gas and isotopic analysis suite of instruments. Drill cuttings were also analyzed by the Alpha Particle X-ray Spectrometer (APXS) for bulk composition. The CheMin XRD analysis shows that the mudstone contains basaltic minerals (Fe-forsterite, augite, pigeonite, plagioclase), as well as Fe-oxide/hydroxides, Fe-sulfides, amorphous materials, and trioctahedral phyllosilicates. SAM evolved gas analysis of higher-temperature OH matches the CheMin XRD estimate of ~20% clay minerals in the mudstone. The light-toned veins contain Ca-sulfates; anhydrite and bassanite are detected by XRD but gypsum is also indicated from Mastcam spectral mapping. These sulfates appear to be almost entirely restricted to late-diagenetic veins. The sulfate content of the mudstone matrix itself is lower than other sediments analyzed on Mars. The presence of phyllosilicates indicates that the activity of water was high during their formation and/or transport and deposition (should they have been detrital). Lack of chlorite places limits on the maximum temperature of alteration (likely <100 C). The presence of Ca-sulfates rather than Mg- or Fe-sulfates suggests that the pore water pH was near-neutral and of relatively low ionic strength (although x-ray amorphous Mg-and Fe- sulfates could be present and undetectable by CheMin). The presence of Fe and S in both reduced and oxidized states represents chemical disequilibria that could have been utilized by chemolithoautotrophic biota, if present. When compared to the nearby Rocknest sand shadow mineralogy or the normative mineralogy of Martian soil, both John Klein and Cumberland exhibit a near-absence of olivine and a surplus of magnetite (7-9% of the crystalline component). The magnetite is interpreted as an authigenic product formed when olivine was altered to phyllosilicate. Saponitization of olivine (a process analogous to serpentinization) could have produced H2 in situ. Indeed, early diagenetic hollow nodules ("minibowls") present in the Cumberland mudstone are interpreted by some as forming when gas bubbles accumulated in the unconsolidated mudstone. Lastly, all of these early diagenetic features appear to have been preserved with minimal alteration since their formation, as indicated by the ease of drilling (weak lithification, lack of cementing phases), the presence of 20-30% amorphous material, and the late-stage fracturing with emplacement of calcium sulfate veins and minibowl infills, where they were intersected by veins. A rough estimate of the minimum duration of the lacustrine environment is provided by the minimum thickness of the Sheepbed member. Given 1.5 meters, and applying a mean sediment accumulation rate for lacustrine strata of 1 m/1000 yrs yields a duration of 1,500 years. If the aqueous environments represented by overlying strata are considered, such as Gillespie Lake and Shaler, then this duration increases. The Sheepbed mudstone meets all the requirements of a habitable environment: Aqueous deposition at clement conditions of P, T, pH, Eh and ionic strength, plus the availability of sources of chemical energy
The Paradox of Power in CSR: A Case Study on Implementation
Purpose Although current literature assumes positive outcomes for stakeholders resulting from an increase in power associated with CSR, this research suggests that this increase can lead to conflict within organizations, resulting in almost complete inactivity on CSR.
Methods A single in-depth case study, focusing on power as an embedded concept.
Results Empirical evidence is used to demonstrate how some actors use CSR to improve their own positions within an organization. Resource dependence theory is used to highlight why this may be a more significant concern for CSR.
Conclusions Increasing power for CSR has the potential to offer actors associated with it increased personal power, and thus can attract opportunistic actors with little interest in realizing the benefits of CSR for the company and its stakeholders. Thus power can be an impediment to furthering CSR strategy and activities at the individual and organizational level
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