2,531 research outputs found
The role of the North Atlantic Oscillation in controlling U.K. butterfly population size and phenology
Copyright @ 2012 The Authors. This article can be accessed from the links below.This article has been made available through the Brunel Open Access Publishing Fund.1. The North Atlantic Oscillation (NAO) exerts considerable control on U.K. weather. This study investigates the impact of the NAO on butterfly abundance and phenology using 34 years of data from the U.K. Butterfly Monitoring Scheme (UKBMS). 2. The study uses a multi-species indicator to show that the NAO does not affect overall U.K. butterfly population size. However, the abundance of bivoltine butterfly species, which have longer flight seasons, were found to be more likely to respond positively to the NAO compared with univoltine species, which show little or a negative response. 3. A positive winter NAO index is associated with warmer weather and earlier flight dates for Anthocharis cardamines (Lepidoptera: Pieridae), Melanargia galathea (Lepidoptera: Nymphalidae), Aphantopus hyperantus (Lepidoptera: Nymphalidae), Pyronia tithonus (Lepidoptera: Nymphalidae), Lasiommata megera (Lepidoptera: Nymphalidae) and Polyommatus icarus (Lepidoptera: Lycaenidae). In bivoltine species, the NAO affects the phenology of the first generation, the timing of which indirectly controls the timing of the second generation. 4. The NAO influences the timing of U.K. butterfly flight seasons more strongly than it influences population size.This study was supported by a multi-agency consortium led by the U.K. Department for Environment, Food and Rural Affairs (Defra), including the Countryside Council for Wales, the Joint Nature Conservation Committee, the Forestry Commission, Natural England, the Natural Environment Research Council, the Northern Ireland Environment Agency and Scottish Natural Heritage. This article is made available through the Brunel Open Access Publishing Fund
Chemical elements in the environment: Multi-element geochemical datasets from continental- to national-scale surveys on four continents
During the last 10–20 years, Geological Surveys around the world have undertaken a major effort towards delivering fully harmonised and tightly quality controlled low-density multi-element soil geochemical maps and datasets of vast regions including up to whole continents. Concentrations of between 45 and 60 elements commonly have been determined in a variety of different regolith types (e.g., sediment, soil). The multi-element datasets are published as complete geochemical atlases and made available to the general public. Several other geochemical datasets covering smaller areas, but generally at a higher spatial density, are also available. These datasets may, however, not be found by superficial internet-based searches because the elements are not mentioned individually either in the title or in the keyword lists of the original references. This publication attempts to increase the visibility and discoverability of these fundamental background datasets covering large areas up to whole continents.We thank the governments and
other sponsors for funding geochemical surveys, field and laboratory
support teams and collaborators for their support, and land owners for
granting access to field sites around the globe
Little Higgses from an Antisymmetric Condensate
We construct an SU(6)/Sp(6) non-linear sigma model in which the Higgses arise
as pseudo-Goldstone bosons. There are two Higgs doublets whose masses have no
one-loop quadratic sensitivity to the cutoff of the effective theory, which can
be at around 10 TeV. The Higgs potential is generated by gauge and Yukawa
interactions, and is distinctly different from that of the minimal
supersymmetric standard model. At the TeV scale, the new bosonic degrees of
freedom are a single neutral complex scalar and a second copy of SU(2)xU(1)
gauge bosons. Additional vector-like pairs of colored fermions are also
present.Comment: 13 page
Choosing more mathematics : happiness through work?
This paper examines how A-level students construct relationships between work and happiness in their accounts of choosing mathematics and further mathematics A-level. I develop a theoretical framework that positions work and happiness as opposed, managed and working on the self and use this to examine students' dual engagement with individual practices of the self and institutional practices of school mathematics. Interviews with students acknowledge four imperatives that they use as discursive resources to position themselves as successful/unsuccessful students: you have to work, you have to not work, you have to be happy, you have to work at being happy. Tensions in these positions lead students to rework their identities or drop further mathematics. I then identify the practices of mathematics teaching that students use to explain un/happiness in work, and show how dependable mathematics and working together are constructed as 'happy objects' for students, who develop strategies for claiming control over these shapers of happiness. © 2010 British Society for Research into Learning Mathematics
Calibration of Smearing and Cooling Algorithms in SU(3)-Color Gauge Theory
The action and topological charge are used to determine the relative rates of
standard cooling and smearing algorithms in pure SU(3)-color gauge theory. We
consider representative gauge field configurations on lattices
at and lattices at . We find the
relative rate of variation in the action and topological charge under various
algorithms may be succinctly described in terms of simple formulae. The results
are in accord with recent suggestions from fat-link perturbation theory.Comment: RevTeX, 25 pages, 22 figures, full resolution jpeg version of Fig. 22
can be obtained from
http://www.physics.adelaide.edu.au/cssm/papers_etc/SmearingComp.jp
Preliminary estimates of the abundance and fidelity of dolphins associating with a demersal trawl fishery
The incidental capture of wildlife in fishing gear presents a global conservation challenge. As a baseline to inform assessments of the impact of bycatch on bottlenose dolphins (Tursiops truncatus) interacting with an Australian trawl fishery, we conducted an aerial survey to estimate dolphin abundance across the fishery. Concurrently, we carried out boat-based dolphin photo-identification to assess short-term fidelity to foraging around trawlers, and used photographic and genetic data to infer longer-term fidelity to the fishery. We estimated abundance at ≈ 2,300 dolphins (95% CI = 1,247-4,214) over the ≈ 25,880-km2 fishery. Mark-recapture estimates yielded 226 (SE = 38.5) dolphins associating with one trawler and some individuals photographed up to seven times over 12 capture periods. Moreover, photographic and genetic re-sampling over three years confirmed that some individuals show long-term fidelity to trawler-associated foraging. Our study presents the first abundance estimate for any Australian pelagic dolphin community and documents individuals associating with trawlers over days, months and years. Without trend data or correction factors for dolphin availability, the impact of bycatch on this dolphin population's conservation status remains unknown. These results should be taken into account by management agencies assessing the impact of fisheries-related mortality on this protected species
Studies of a three-stage dark matter and neutrino observatory based on multi-ton combinations of liquid xenon and liquid argon detectors
We study a three stage dark matter and neutrino observatory based on
multi-ton two-phase liquid Xe and Ar detectors with sufficiently low
backgrounds to be sensitive to WIMP dark matter interaction cross sections down
to 10E-47 cm^2, and to provide both identification and two independent
measurements of the WIMP mass through the use of the two target elements in a
5:1 mass ratio, giving an expected similarity of event numbers. The same
detection systems will also allow measurement of the pp solar neutrino
spectrum, the neutrino flux and temperature from a Galactic supernova, and
neutrinoless double beta decay of 136Xe to the lifetime level of 10E27 - 10E28
y corresponding to the Majorana mass predicted from current neutrino
oscillation data. The proposed scheme would be operated in three stages G2, G3,
G4, beginning with fiducial masses 1-ton Xe + 5-ton Ar (G2), progressing to
10-ton Xe + 50-ton Ar (G3) then, dependent on results and performance of the
latter, expandable to 100-ton Xe + 500-ton Ar (G4). This method of scale-up
offers the advantage of utilizing the Ar vessel and ancillary systems of one
stage for the Xe detector of the succeeding stage, requiring only one new
detector vessel at each stage. Simulations show the feasibility of reducing or
rejecting all external and internal background levels to a level <1 events per
year for each succeeding mass level, by utilizing an increasing outer thickness
of target material as self-shielding. The system would, with increasing mass
scale, become increasingly sensitive to annual signal modulation, the agreement
of Xe and Ar results confirming the Galactic origin of the signal. Dark matter
sensitivities for spin-dependent and inelastic interactions are also included,
and we conclude with a discussion of possible further gains from the use of
Xe/Ar mixtures
Statistical Survey of Type III Radio Bursts at Long Wavelengths Observed by the Solar TErrestrial RElations Observatory (STEREO)/Waves Instruments: Radio Flux Density Variations with Frequency
We have performed a statistical study of Type III radio bursts observed
by Solar TErrestrial RElations Observatory (STEREO)/Waves between May 2007 and
February 2013. We have investigated the flux density between kHz and
MHz. Both high- and low-frequency cutoffs have been observed in of
events suggesting an important role of propagation. As already reported by
previous authors, we observed that the maximum flux density occurs at MHz on
both spacecraft. We have developed a simplified analytical model of the flux
density as a function of radial distance and compared it to the STEREO/Waves
data.Comment: published in Solar Physic
The Upper Critical Field in Disordered Two-Dimensional Superconductors
We present calculations of the upper critical field in superconducting films
as a function of increasing disorder (as measured by the normal state
resistance per square). In contradiction to previous work, we find that there
is no anomalous low-temperature positive curvature in the upper critical field
as disorder is increased. We show that the previous prediction of this effect
is due to an unjustified analytical approximation of sums occuring in the
perturbative calculation. Our treatment includes both a careful analysis of
first-order perturbation theory, and a non-perturbative resummation technique.
No anomalous curvature is found in either case. We present our results in
graphical form.Comment: 11 pages, 8 figure
A semantical approach to equilibria and rationality
Game theoretic equilibria are mathematical expressions of rationality.
Rational agents are used to model not only humans and their software
representatives, but also organisms, populations, species and genes,
interacting with each other and with the environment. Rational behaviors are
achieved not only through conscious reasoning, but also through spontaneous
stabilization at equilibrium points.
Formal theories of rationality are usually guided by informal intuitions,
which are acquired by observing some concrete economic, biological, or network
processes. Treating such processes as instances of computation, we reconstruct
and refine some basic notions of equilibrium and rationality from the some
basic structures of computation.
It is, of course, well known that equilibria arise as fixed points; the point
is that semantics of computation of fixed points seems to be providing novel
methods, algebraic and coalgebraic, for reasoning about them.Comment: 18 pages; Proceedings of CALCO 200
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