28,460 research outputs found
The Ecosystem Approach to Fisheries: Issues, Terminology, Principles, Institutional Foundations, Implementation and Outlook
Ecosystems are complex and dynamic natural units that produce goods and services beyond those of benefit to fisheries. Because fisheries have a direct impact on the ecosystem, which is also impacted by other human activities, they need to be managed in an ecosystem context. The meaning of the terms 'ecosystem management', 'ecosystem based management', 'ecosystem approach to fisheries'(EAF), etc., are still not universally defined and progressively evolving. The justification of EAF is evident in the characteristics of an exploited ecosystem and the impacts resulting from fisheries and other activities. The rich set of international agreements of relevance to EAF contains a large number of principles and conceptual objectives. Both provide a fundamental guidance and a significant challenge for the implementation of EAF. The available international instruments also provide the institutional foundations for EAF. The FAO Code of Conduct for Responsible Fisheries is particularly important in this respect and contains provisions for practically all aspects of the approach. One major difficulty in defining EAF lies precisely in turning the available concepts and principles into operational objectives from which an EAF management plan would more easily be developed. The paper discusses these together with the types of action needed to achieve them. Experience in EAF implementation is still limited but some issues are already apparent, e.g. in added complexity, insufficient capacity, slow implementation, need for a pragmatic approach, etc. It is argued, in conclusion, that the future of EAF and fisheries depends on the way in which the two fundamental concepts of fisheries management and ecosystem management, and their respective stakeholders, will join efforts or collide
Adaptive Optics Observations of the Galactic Center Young Stars
Adaptive Optics observations have dramatically improved the quality and
versatility of high angular resolution measurements of the center of our
Galaxy. In this paper, we quantify the quality of our Adaptive Optics
observations and report on the astrometric precision for the young stellar
population that appears to reside in a stellar disk structure in the central
parsec. We show that with our improved astrometry and a 16 year baseline,
including 10 years of speckle and 6 years of laser guide star AO imaging, we
reliably detect accelerations in the plane of the sky as small as 70
microarcsec/yr/yr (~2.5 km/s/yr) and out to a projected radius from the
supermassive black hole of 1.5" (~0.06 pc). With an increase in sensitivity to
accelerations by a factor of ~6 over our previous efforts, we are able to
directly probe the kinematic structure of the young stellar disk, which appears
to have an inner radius of 0.8". We find that candidate disk members are on
eccentric orbits, with a mean eccentricity of = 0.30 +/- 0.07. Such
eccentricities cannot be explained by the relaxation of a circular disk with a
normal initial mass function, which suggests the existence of a top-heavy IMF
or formation in an initially eccentric disk.Comment: 7 pages, 4 figures, SPIE Astronomical Telescopes and Instrumentation
201
THE EFFECT OF LANGUAGE BARRIERS ON VARIATION AND RECEIPT OF EARLY STAGE BREAST CANCER TREATMENT
Background: Arriving at and implementing an appropriate patient centered treatment plan for early stage breast cancer requires significant dialogue between healthcare providers and patients. How language barriers affect this process has not been thoroughly explored in the literature. The aim of this paper is to examine the effect of language barrier on variation and receipt of early stage breast cancer treatment.
Methods: Rates of lumpectomy, mastectomy, and contralateral prophylactic mastectomy (CPM) with or without reconstruction were compared between English speaking and Low English Proficiency (LEP) cohorts. Patients with recurrent or bilateral breast cancer, male patients, and/or known genetic mutations were excluded. Receipt of recommended treatments including chemotherapy, hormonal therapy and radiation were compared between the two groups, as well as patient refusal and loss of follow-up. Regression analysis for all-cause mortality within this time period was tabulated for each group.
Results: There were no significant differences between receipt of recommended treatments, patient refusal or loss of follow up between the cohorts. LEP patients had a greater proportion of lumpectomies (79.7 versus 70.7%) while 9.2% of English-speaking patients had CPM or CPM with reconstruction compared to none of the LEP patients. These trends, however, did not rise to statistical significance within our small population sample. Age, insurance type, and LEP were associated with significant difference in all-cause mortality, however only age and insurance remained significant in adjusted analysis.
Conclusion: Our results indicate a non-statistically significant trend towards less variation of surgical treatment variation for early stage breast cancer in the LEP population, including a greater frequency of lumpectomy and less utilization of CPM. Larger, multicenter studies would be needed to affirm and further investigate these trends
Emergent bipartiteness in a society of knights and knaves
We propose a simple model of a social network based on so-called
knights-and-knaves puzzles. The model describes the formation of networks
between two classes of agents where links are formed by agents introducing
their neighbours to others of their own class. We show that if the proportion
of knights and knaves is within a certain range, the network self-organizes to
a perfectly bipartite state. However, if the excess of one of the two classes
is greater than a threshold value, bipartiteness is not observed. We offer a
detailed theoretical analysis for the behaviour of the model, investigate its
behaviou r in the thermodynamic limit, and argue that it provides a simple
example of a topology-driven model whose behaviour is strongly reminiscent of a
first-order phase transitions far from equilibrium.Comment: 12 pages, 5 figure
Própolis: uma alternativa para diversificar a produção apícola.
O mel é o principal produto da apicultura, principalmente nos estados do Nordeste. Entretanto, nos últimos anos, a produção de própolis tem adquirido maior importância no agronegócio apícola, verificando-se aumento de demanda no mercado interno e significativa representação nas exportações do setor...bitstream/item/123253/1/Saude-Animal.pd
Efeitos de herbicida sobre animais em pastejo.
bitstream/item/57819/1/Animaispastejo0001.pd
Top quark and Electroweak measurements at the Tevatron
We present recent preliminary measurements at the Tevatron of t-tbar and
single top production cross section, top quark mass and width, top pair spin
correlations and forward-backward asymmetry. In the electroweak sector, we
present the Tevatron average of the W boson width, and preliminary measurements
of the W and Z forward-backward asymmetries and WZ, ZZ diboson production cross
sections. All measurements are based on larger amount of collision data than
previously used and are in agreement with the standard model.Comment: 6 pages, 6 figures; In proceedings of the 16th International
Symposium on Particles, Strings and Cosmology, Valencia (Spain) 201
The Influence of Gravity on Particle Collision and Agglomeration in Turbulent Channel Flows
The study described in this paper concerns the simulation of a particle-laden turbulent channel flow at high mass loadings, with and without the presence of gravity. Large eddy simulation (LES) is used to simulate the fluid phase, with solutions combined with a Lagrangian particle tracker to model the particle phase. Particle-particle interactions are detected using an algorithm based on a deterministic collision treatment (hard-sphere collision model), and particle agglomeration is based on the use of a particle restitution coefficient, energy balance and the sum of the van der Waals’ force on each colliding particle. In order to establish the validity of the treatment, results are compared with those based on a DNS, with good agreement being found. Subsequent runs for colliding and agglomerating particles in a channel flow demonstrate that the rate of particle agglomeration peaks towards the channel walls due to increased particle concentrations and turbulence levels in these regions. Agglomeration is also greatly influenced by the presence of gravity, with this effect accentuated on the lower wall of the channel
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