1,963 research outputs found
A new framework of spatial targeting for single-species conservation planning
Context: Organisations acting to conserve and protect species across large spatial scales prioritise to optimise use of resources. Spatial conservation prioritization tools typically focus on identifying areas containing species groups of interest, with few tools used to identify the best areas for single-species conservation, in particular, to conserve currently widespread but declining species. /
Objective: A single-species prioritization framework, based on temporal and spatial patterns of occupancy and abundance, was developed to spatially prioritize conservation action for widespread species by identifying smaller areas to work within to achieve predefined conservation objectives. /
Methods: We demonstrate our approach for 29 widespread bird species in the UK, using breeding bird atlas data from two periods to define distribution, relative abundance and change in relative abundance. We selected occupied 10-km squares with abundance trends that matched species conservation objectives relating to maintaining or increasing population size or range, and then identified spatial clusters of squares for each objective using a Getis-Ord-Gi* or near neighbour analysis. /
Results: For each species, the framework identified clusters of 20-km squares that enabled us to identify small areas in which species recovery action could be prioritized. /
Conclusions: Our approach identified a proportion of species’ ranges to prioritize for species recovery. This approach is a relatively quick process that can be used to inform single-species conservation for any taxa if sufficiently fine-scale occupancy and abundance information is available for two or more time periods. This is a relatively simple first step for planning single-species focussed conservation to help optimise resource use
Comment on "Bicritical and Tetracritical Phenomena and Scaling Properties of the SO(5) Theory"
The multicritical point at which both a 3-component and a 2-component order
parameters order simultaneously in 3 dimensions is shown to have the critical
behavior of the decoupled fixed point, with separate n=3 and n=2 behavior. This
contradicts both the extrapolation of the epsilon-expansion at leading order,
which yields the biconical point, and recent Monte Carlo simulations, which
gave isotropic SO(5) behavior. Thus, this tetracritical point carries no
information on the relevance of the so-called SO(5) theory of high-T
superconductivity.Comment: 1 pag
Exploring experiences and impact of the COVID-19 pandemic on young racially minoritised people in the United Kingdom: A Qualitative Study
Within high-income-countries, the COVID-19 pandemic has disproportionately impacted people from racially minoritised backgrounds. There has been significant research interrogating the disparate impact of the virus, and recently, interest in the long-term implications of the global crisis on young people’s mental health and wellbeing. However, less work explores the experiences of young people from racialised backgrounds as they navigate the pandemic, and the specific consequences this has for their mental health. Forty young people (age 16-25) from black, mixed and other minority backgrounds and living in London, participated in consecutive focus group discussions over a two-month period, to explore the impact of the pandemic on their lives and emotional wellbeing. Thematic analysis identified seven categories describing the impact of the pandemic, indicating: deepening of existing socioeconomic and emotional challenges; efforts to navigate racism and difference within the response; and survival strategies drawing on communal and individual resources. Young people also articulated visions for a future public health response which addressed gaps in current strategies. Findings point to the need to contextualise public health responses to the pandemic in line with the lived experiences of racialised young people. We specifically note the importance of long-term culturally and socio-politically relevant support interventions. Implications for policy and practice are discusse
Solar Neutrinos and the Eclipse Effect
The solar neutrino counting rate in a real time detector like
Super--Kamiokanda, SNO, or Borexino is enhanced due to neutrino oscillations in
the Moon during a partial or total solar eclipse. The enhancement is calculated
as a function of the neutrino parameters in the case of three flavor mixing.
This enhancement, if seen, can further help to determine the neutrino
parameters.Comment: 24 Pages Revtex, 8 figures as one ps file. To appear in Phys. Rev. D;
Some typos corrected and a reference adde
Limits on a Composite Higgs Boson
Precision electroweak data are generally believed to constrain the Higgs
boson mass to lie below approximately 190 GeV at 95% confidence level. The
standard Higgs model is, however, trivial and can only be an effective field
theory valid below some high energy scale characteristic of the underlying
non-trivial physics. Corrections to the custodial isospin violating parameter T
arising from interactions at this higher energy scale dramatically enlarge the
allowed range of Higgs mass. We perform a fit to precision electroweak data and
determine the region in the (m_H, Delta T) plane that is consistent with
experimental results. Overlaying the estimated size of corrections to T arising
from the underlying dynamics, we find that a Higgs mass up to 500 GeV is
allowed. We review two composite Higgs models which can realize the possibility
of a phenomenologically acceptable heavy Higgs boson. We comment on the
potential of improvements in the measurements of m_t and M_W to improve
constraints on composite Higgs models.Comment: 9 pages, 2 eps figures. Shortened for PRL; some references elminate
Rest-frame properties of 32 gamma-ray bursts observed by the Fermi Gamma-Ray Burst Monitor
Aims: In this paper we study the main spectral and temporal properties of
gamma-ray bursts (GRBs) observed by Fermi/GBM. We investigate these key
properties of GRBs in the rest-frame of the progenitor and test for possible
intra-parameter correlations to better understand the intrinsic nature of these
events. Methods: Our sample comprises 32 GRBs with measured redshift that were
observed by GBM until August 2010. 28 of them belong to the long-duration
population and 4 events were classified as short/hard bursts. For all of these
events we derive, where possible, the intrinsic peak energy in the spectrum (\eprest), the duration in the rest-frame, defined as the
time in which 90% of the burst fluence was observed (\tninetyrest) and the
isotropic equivalent bolometric energy (\eiso). Results: The distribution of
\eprest has mean and median values of 1.1 MeV and 750 keV, respectively. A
log-normal fit to the sample of long bursts peaks at ~800 keV. No high-\ep
population is found but the distribution is biased against low \ep values. We
find the lowest possible \ep that GBM can recover to be ~ 15 keV. The
\tninetyrest distribution of long GRBs peaks at ~10 s. The distribution of
\eiso has mean and median values of erg and erg, respectively. We confirm the tight correlation between \eprest
and \eiso (Amati relation) and the one between \eprest and the 1-s peak
luminosity () (Yonetoku relation). Additionally, we observe a parameter
reconstruction effect, i.e. the low-energy power law index gets softer
when \ep is located at the lower end of the detector energy range. Moreover, we
do not find any significant cosmic evolution of neither \eprest nor
\tninetyrest.Comment: accepted by A&
Higgs-Boson Mass Limits and Precise Measurements beyond the Standard Model
The triviality and vacuum stability bounds on the Higgs-boson mass (\mh)
were revisited in presence of weakly-coupled new interactions parameterized in
a model-independent way by effective operators of dimension 6. The constraints
from precision tests of the Standard Model were taken into account. It was
shown that for the scale of new physics in the region \Lambda \simeq 2 \div 50
\tev the Standard Model triviality upper bound remains unmodified whereas it
is natural to expect that the lower bound derived from the requirement of
vacuum stability is substantially modified depending on the scale \La and
strength of coefficients of effective operators. A natural generalization of
the standard triviality condition leads also to a substantial reduction of the
allowed region in the (\Lambda,\mh) space.Comment: 18 pages 3 eps figures. The discussion in the appendix was modified
slightly and some typographical errors were correcte
Comparison of assessments of fitness to drive for people with dementia
Cognitive tests are used to inform recommendations about the fitness to drive of people with dementia. The Rookwood Driving Battery (RDB) and Dementia Drivers' Screening Assessment (DDSA) are neuropsychological batteries designed to assist in this process. The aim was to assess the concordance between the classifications (pass/fail) of the RDB and DDSA in individuals with dementia, and to compare any discordant classifications against on-road driving ability. Participants were identified by community mental health teams and psychiatrists. Twenty four participants were recruited. The mean age was 74.1 (SD 8.9) years and 18 (75%) were men. Each participant was assessed on the RDB and DDSA in an order determined by random allocation. Those with discrepant results also had an on-road assessment. The agreement between the tests was 54% using a cut-off of > 6 on the RDB, and 75% using the cut-off to > 10 on the RDB. Three participants with discrepant results agreed to be assessed on the road and all were found to be safe to drive. The findings suggested that there was poor concurrent validity between the RDB and DDSA. This raises questions about the choice of assessments in making clinical recommendations about fitness to drive in people with dementia
Correlation Functions of Large N Chern-Simons-Matter Theories and Bosonization in Three Dimensions
We consider the conformal field theory of N complex massless scalars in 2+1
dimensions, coupled to a U(N) Chern-Simons theory at level k. This theory has a
't Hooft large N limit, keeping fixed \lambda = N/k. We compute some
correlation functions in this theory exactly as a function of \lambda, in the
large N (planar) limit. We show that the results match with the general
predictions of Maldacena and Zhiboedov for the correlators of theories that
have high-spin symmetries in the large N limit. It has been suggested in the
past that this theory is dual (in the large N limit) to the Legendre transform
of the theory of fermions coupled to a Chern-Simons gauge field, and our
results allow us to find the precise mapping between the two theories. We find
that in the large N limit the theory of N scalars coupled to a U(N)_k
Chern-Simons theory is equivalent to the Legendre transform of the theory of k
fermions coupled to a U(k)_N Chern-Simons theory, thus providing a bosonization
of the latter theory. We conjecture that perhaps this duality is valid also for
finite values of N and k, where on the fermionic side we should now have (for
N_f flavors) a U(k)_{N-N_f/2} theory. Similar results hold for real scalars
(fermions) coupled to the O(N)_k Chern-Simons theory.Comment: 49 pages, 16 figures. v2: added reference
Correlations and Renormalization in Lattice Gases
A complete formulation is given of an exact kinetic theory for lattice gases.
This kinetic theory makes possible the calculation of corrections to the usual
Boltzmann / Chapman-Enskog analysis of lattice gases due to the buildup of
correlations. It is shown that renormalized transport coefficients can be
calculated perturbatively by summing terms in an infinite series. A
diagrammatic notation for the terms in this series is given, in analogy with
the diagrammatic expansions of continuum kinetic theory and quantum field
theory. A closed-form expression for the coefficients associated with the
vertices of these diagrams is given. This method is applied to several standard
lattice gases, and the results are shown to correctly predict experimentally
observed deviations from the Boltzmann analysis.Comment: 94 pages, pure LaTeX including all figure
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