471 research outputs found
Fisheries interactions of Delphinus delphis in the north-east Atlantic with an emphasis on Galicia, north-west Spain.
Bycatch from interactions with fisherie
s remains the biggest global threat to marine
mammals. Galicia, north
-
west Spain, is one of the world’s main fishing regions and a high
level of cetacean
-
fisheries interactions has been reported from on
-
board observers, interviews
with fisheries stakeholde
rs and analysis of stranded and by
-
caught carcasses.
Delphinus
delphis
is the most abundant cetacean in the area and since 1990 necropsies of over 1800
stranded and by
-
caught
Delphinus
have been conducted. Life history data (age, maturity, and
pregnancy ra
te data) from stranded and by
-
caught cetaceans can be used to construct life
tables and to estimate overall mortality and fisheries mortality rates. Age and maturity were
determined from stranded and by
-
caught
Delphinus
between 1990 and 2009. Males and
fem
ales reach sexual maturity at 8.5 and 7.5 years of age, respectively, and no temporal
difference in age at sexual maturity was observed. Results indicate 13% annual mortality in
the
Delphinus delphis
north
-
east Atlantic population and necropsy data suggest
s that 60% of
mortality (i.e. 7.2% annual mortality) is attributable to fisheries interactions, predominantly
from pair trawls and gillnets. By
-
caught
Delphinus
were found to die significantly younger
than non
-
by
-
caught animals (p=<0.001) although no sex
-
r
elated difference in bycatch rate
was observed (p=0.051). The estimated annual mortality due to fisheries interactions greatly
exceeds the 2% limit set by ASCOBANS and the IWC and high bycatch rates are also
reported for other countries e.g. the UK, France
and Portugal. Although
Delphinus delphis
in
the north
-
east Atlantic is one continuous population, the high level of bycatch occurring in
parts of the range is most likely unsustainable and will be discussed. There is a need to carry
out on
-
board monitorin
g, notably in the north
-
west Iberian Peninsula (Galicia and Portugal),
to incorporate cetacean bycatch into fisheries advice and, above all, to start introducing
mitigation measures
The UK risk assessment scheme for all non-native species
1. A pest risk assessment scheme, adapted from the EPPO (European and Mediterranean Plant Protection Organisation) scheme, was developed to assess the risks posed to UK species, habitats and ecosystems by non-native taxa.
2. The scheme provides a structured framework for evaluating the potential for non-native organisms, whether intentional or unintentional introductions, to enter, establish, spread and cause significant impacts in all or part of the UK. Specialist modules permit the relative importance of entry pathways, the vulnerability of receptors and the consequences of policies to be assessed and appropriate risk management options to be selected. Spreadsheets for summarising the level of risk and uncertainty, invasive attributes and economic impact were created. In addition, new methods for quantifying economic impact and summarising risk and uncertainty were explored.
3. Although designed for the UK, the scheme can readily be applied elsewhere
Sudden switch of generalized Lieb-Robinson velocity in a transverse field Ising spin chain
The Lieb-Robinson theorem states that the speed at which the correlations
between two distant nodes in a spin network can be built through local
interactions has an upper bound, which is called the Lieb-Robinson velocity.
Our central aim is to demonstrate how to observe the Lieb-Robinson velocity in
an Ising spin chain with a strong transverse field. We adopt and compare four
correlation measures for characterizing different types of correlations, which
include correlation function, mutual information, quantum discord, and
entanglement of formation. We prove that one of correlation functions shows a
special behavior depending on the parity of the spin number. All the
information-theoretical correlation measures demonstrate the existence of the
Lieb-Robinson velocity. In particular, we find that there is a sudden switch of
the Lieb-Robinson speed with the increasing of the number of spin
Are markers of inflammation more strongly associated with risk for fatal than for nonfatal vascular events?
<p><b>Background:</b> Circulating inflammatory markers may more strongly relate to risk of fatal versus nonfatal cardiovascular disease (CVD) events, but robust prospective evidence is lacking. We tested whether interleukin (IL)-6, C-reactive protein (CRP), and fibrinogen more strongly associate with fatal compared to nonfatal myocardial infarction (MI) and stroke.</p>
<p><b>Methods and Findings:</b> In the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER), baseline inflammatory markers in up to 5,680 men and women aged 70-82 y were related to risk for endpoints; nonfatal CVD (i.e., nonfatal MI and nonfatal stroke [n = 672]), fatal CVD (n = 190), death from other CV causes (n = 38), and non-CVD mortality (n = 300), over 3.2-y follow-up. Elevations in baseline IL-6 levels were significantly (p = 0.0009; competing risks model analysis) more strongly associated with fatal CVD (hazard ratio [HR] for 1 log unit increase in IL-6 1.75, 95% confidence interval [CI] 1.44-2.12) than with risk of nonfatal CVD (1.17, 95% CI 1.04-1.31), in analyses adjusted for treatment allocation. The findings were consistent in a fully adjusted model. These broad trends were similar for CRP and, to a lesser extent, for fibrinogen. The results were also similar in placebo and statin recipients (i.e., no interaction). The C-statistic for fatal CVD using traditional risk factors was significantly (+0.017; p<0.0001) improved by inclusion of IL-6 but not so for nonfatal CVD events (p = 0.20).</p>
<p><b>Conclusions:</b> In PROSPER, inflammatory markers, in particular IL-6 and CRP, are more strongly associated with risk of fatal vascular events than nonfatal vascular events. These novel observations may have important implications for better understanding aetiology of CVD mortality, and have potential clinical relevance.</p>
Double-Layer Systems at Zero Magnetic Field
We investigate theoretically the effects of intralayer and interlayer
exchange in biased double-layer electron and hole systems, in the absence of a
magnetic field. We use a variational Hartree-Fock-like approximation to analyze
the effects of layer separation, layer density, tunneling, and applied gate
voltages on the layer densities and on interlayer phase coherence. In agreement
with earlier work, we find that for very small layer separations and low layer
densities, an interlayer-correlated ground state possessing spontaneous
interlayer coherence (SILC) is obtained, even in the absence of interlayer
tunneling. In contrast to earlier work, we find that as a function of total
density, there exist four, rather than three, distinct noncrystalline phases
for balanced double-layer systems without interlayer tunneling. The newly
identified phase exists for a narrow range of densities and has three
components and slightly unequal layer densities, with one layer being spin
polarized, and the other unpolarized. An additional two-component phase is also
possible in the presence of sufficiently strong bias or tunneling. The
lowest-density SILC phase is the fully spin- and pseudospin-polarized
``one-component'' phase discussed by Zheng {\it et al.} [Phys. Rev. B {\bf 55},
4506 (1997)]. We argue that this phase will produce a finite interlayer Coulomb
drag at zero temperature due to the SILC. We calculate the particle densities
in each layer as a function of the gate voltage and total particle density, and
find that interlayer exchange can reduce or prevent abrupt transfers of charge
between the two layers. We also calculate the effect of interlayer exchange on
the interlayer capacitance.Comment: 35 pages, 19 figures included. To appear in PR
Moving beyond Goffman: the performativity of anonymity on SNS
Purpose: This paper explores consumer behaviour on the popular anonymous social networking site (SNS) Yik Yak. It examines the reasons behind the turn to anonymous social networking and also considers the ways in which anonymity impacts consumers' self-performances on SNS.
Design/methodology/approach: The study used a netnographic approach to explore Yik Yak across eight universities in Ireland and the UK. Data are based on observation and participation on the app. Screenshots on smart phones were the central method used to collect data. Data also included twelve in-depth interviews.
Findings: Young consumers are becoming fatigued by the negative effects of self-presentation on many SNS. By enabling consumers to engage in what they consider to be more authentic modes of being and interaction, Yik Yak provides respite from these pressures. Through the structures of its design, Yik Yak enables consumers to realise self-authentication in anonymised self-performances that engender a sense of virtue and social connection.
Originality/value: By invoking a performative lens, this paper extends a novel theoretical approach to understandings of identity formation within consumer research. Highlighting anonymity as a dynamic process of socio- material enactments, the study reveals how consumers' self-performances are brought into effect through the citation of various discursive arrangements, which promulgate distinct understandings of authenticity.
Practical implications: This research highlights the potential value of anonymous SNS in fostering supportive dialogue, concerning mental health amongst post-millennials
A First Search for coincident Gravitational Waves and High Energy Neutrinos using LIGO, Virgo and ANTARES data from 2007
We present the results of the first search for gravitational wave bursts
associated with high energy neutrinos. Together, these messengers could reveal
new, hidden sources that are not observed by conventional photon astronomy,
particularly at high energy. Our search uses neutrinos detected by the
underwater neutrino telescope ANTARES in its 5 line configuration during the
period January - September 2007, which coincided with the fifth and first
science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed
for candidate gravitational-wave signals coincident in time and direction with
the neutrino events. No significant coincident events were observed. We place
limits on the density of joint high energy neutrino - gravitational wave
emission events in the local universe, and compare them with densities of
merger and core-collapse events.Comment: 19 pages, 8 figures, science summary page at
http://www.ligo.org/science/Publication-S5LV_ANTARES/index.php. Public access
area to figures, tables at
https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=p120000
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