1,767 research outputs found
Key biological information for the management of Black Bream in the Vasse-Wonnerup
The Vasse-Wonnerup is a shallow intermittently-open system located near the town of Busselton, Western Australia and is listed under the Ramsar Convention. Despite its ecological importance, the Vasse-Wonnerup is highly modified and suffers from excess nutrients, low oxygen levels, which can lead to fish kills. A major component of the fish that die during these kills is the iconic recreational species Black Bream (Acanthopagrus butcheri). Because Black Bream are a solely estuarine species, i.e. individuals complete their life cycle within the estuary and do not leave, depleted populations of this species cannot be replenished from stocks in the marine environment or from other estuaries.
Results from previous studies in the Vasse-Wonnerup demonstrated that, following a major fish kill in April 2013 there was no evidence of recruitment (an increase in juveniles following the birth of new fish) of Black Bream from that year. It was not known, however, whether this was due to the environment at the time of spawning not being conducive for survival or to a lack of sufficient numbers of brood stock (sexually mature fish) and thus whether recruitment would continue to fail in the future. It also became apparent that the good, thorough information required for management of this fish in the Vasse-Wonnerup was lacking. There was thus an urgent need to acquire information on the key biological characteristics of Black Bream and assess the health of this stock in the Vasse-Wonnerup
Critical exponents in Ising spin glasses
We determine accurate values of ordering temperatures and critical exponents
for Ising Spin Glass transitions in dimension 4, using a combination of finite
size scaling and non-equilibrium scaling techniques. We find that the exponents
and vary with the form of the interaction distribution, indicating
non-universality at Ising spin glass transitions. These results confirm
conclusions drawn from numerical data for dimension 3.Comment: 6 pages, RevTeX (or Latex, etc), 10 figures, Submitted to PR
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Distinctive impact craters are formed by organic rich cometary dust grains
Introduction: Preliminary Examination (PE) of the Stardust cometary collector revealed many tracks in the silica aerogel and impact craters on aluminium (Al) foil, from which Wild 2 dust particle fluence and size distribution were determined. Laboratory light gas gun (LGG) shots provided impactor size calibrations. Analogue impacts of diverse mineral compositions and aggregate particles aided
interpretation of dust composition and structure. We now describe our recent impact experiments on foil by organic materials, which reveal distinctive crater surface textures, and even preserved residue
Residential mobility and childhood leukemia.
AimsStudies of environmental exposures and childhood leukemia studies do not usually account for residential mobility. Yet, in addition to being a potential risk factor, mobility can induce selection bias, confounding, or measurement error in such studies. Using data collected for California Powerline Study (CAPS), we attempt to disentangle the effect of mobility.MethodsWe analyzed data from a population-based case-control study of childhood leukemia using cases who were born in California and diagnosed between 1988 and 2008 and birth certificate controls. We used stratified logistic regression, case-only analysis, and propensity-score adjustments to assess predictors of residential mobility between birth and diagnosis, and account for potential confounding due to residential mobility.ResultsChildren who moved tended to be older, lived in housing other than single-family homes, had younger mothers and fewer siblings, and were of lower socioeconomic status. Odds ratios for leukemia among non-movers living <50 meters (m) from a 200+ kilovolt line (OR: 1.62; 95% CI: 0.72-3.65) and for calculated fields âĽâŻ0.4 microTesla (OR: 1.71; 95% CI: 0.65-4.52) were slightly higher than previously reported overall results. Adjustments for propensity scores based on all variables predictive of mobility, including dwelling type, increased odds ratios for leukemia to 2.61 (95% CI: 1.76-3.86) for living <âŻ50âŻm from a 200âŻ+ kilovolt line and to 1.98 (1.11-3.52) for calculated fields. Individual or propensity-score adjustments for all variables, except dwelling type, did not materially change the estimates of power line exposures on childhood leukemia.ConclusionThe residential mobility of childhood leukemia cases varied by several sociodemographic characteristics, but not by the distance to the nearest power line or calculated magnetic fields. Mobility appears to be an unlikely explanation for the associations observed between power lines exposure and childhood leukemia
Supersymmetric NambuJona-Lasinio Model on four-dimensional Non(anti)commutative Superspace
We construct the Lagrangian of the four-dimensional generalized
supersymmetric NambuJona-Lasinio (SNJL) model, which has
supersymmetry (SUSY) on non(anti)commutative superspace. A special attention is
paid to the examination on the nonperturbative quantum dynamics: The phenomenon
of dynamical-symmetry-breaking/mass-generation on the deformed superspace is
investigated. The model Lagrangian and the method of SUSY auxiliary fields of
composites are examined in terms of component fields. We derive the effective
action, examine it, and solve the gap equation for self-consistent mass
parameters.Comment: 16 pages, TeX mistakes corrected, accepted for publication in JHEP,
25 Jan. 200
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Microcraters in aluminum foils exposed by Stardust
We will present preliminary results on the nature and size frequency distribution of microcraters that formed in aluminum foils during the flyby of comet Wild 2 by the Stardust spacecraft
Recurrent dynamical symmetry breaking and restoration by Wilson lines at finite densities on a torus
In this paper we derive the general expression of a one-loop effective
potential of the nonintegrable phases of Wilson lines for an SU(N) gauge theory
with a massless adjoint fermion defined on the spactime manifold
at finite temperature and fermion density. The Phase
structure of the vacuum is presented for the case with and N=2 at zero
temperature. It is found that gauge symmetry is broken and restored alternately
as the fermion density increases, a feature not found in the Higgs mechanism.
It is the manifestation of the quantum effects of the nonintegrable phases.Comment: 17 pages, 2 figure
Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events
The - oscillation frequency has been measured with a sample of
23 million \B\bar B pairs collected with the BABAR detector at the PEP-II
asymmetric B Factory at SLAC. In this sample, we select events in which both B
mesons decay semileptonically and use the charge of the leptons to identify the
flavor of each B meson. A simultaneous fit to the decay time difference
distributions for opposite- and same-sign dilepton events gives ps.Comment: 7 pages, 1 figure, submitted to Physical Review Letter
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
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