1,354 research outputs found
Variability of physical factors relevant to fisheries production in the Mediterranean Sea, North Sea and Baltic Sea
Recent publications have shown that river runoff and wind mixing are two major environmental factors affecting productivity of fish populations in subtropical and tropical areas, as opposed to water temperature in colder waters. In the present paper, we compare the variability of seawater temperature, river runoff and wind mixing in three different seas: a subtropical sea (the Mediterranean) and two cold seas (the North Sea and the Baltic). Temperature variability decreased from colder to warmer areas. The highest temporal variability in the river runoff corresponded to rivers flowing into the Mediterranean, and the lowest corresponded to rivers flowing into the North Sea and the Baltic Sea. The variability in the wind mixing index (cube of the wind speed) depended on the area under consideration, and attained maximum values in the Cap Béar station (northwestern Mediterranean). The effect of these regional variability differences in environmental factors on fisheries production is briefly discussed.Investigaciones recientes demuestran que las descargas fluviales y los vientos son factores ambientales clave para la productividad de las poblaciones explotadas en zonas subtropicales y tropicales, mientras que en mares fríos la temperatura del agua constituye el factor ambiental más importante para la productividad pesquera. Este estudio compara las diferencias geográficas en la variabilidad temporal de tres factores físicos (temperatura del agua, aportes fluviales y velocidad del viento) en un mar subtropical (Mediterráneo) y dos mares fríos (Mar del Norte y Báltico). La variabilidad temporal de la temperatura del agua es mayor en los dos mares fríos que en el subtropical. Así mismo, los ríos que desembocan en el Mediterráneo presentan mayor variabilidad temporal en cuanto a los aportes fluviales que los ríos que desembocan en el Mar del Norte y el mar Báltico. La variabilidad temporal en el índice de mezcla del viento (velocidad del viento al cubo) es distinta según la zona que se considere, y es máxima en la estación de Cap Béar (Mediterráneo noroccidental). Finalmente, se discuten los efectos de esta variabilidad ambiental geográfica sobre las poblaciones explotadas.Instituto Español de Oceanografí
Scaling analysis of the magnetic monopole mass and condensate in the pure U(1) lattice gauge theory
We observe the power law scaling behavior of the monopole mass and condensate
in the pure compact U(1) gauge theory with the Villain action. In the Coulomb
phase the monopole mass scales with the exponent \nu_m=0.49(4). In the
confinement phase the behavior of the monopole condensate is described with
remarkable accuracy by the exponent \beta_{exp}=0.197(3). Possible implications
of these phenomena for a construction of a strongly coupled continuum U(1)
gauge theory are discussed.Comment: Added references [1
Being Warm Being Happy: fuel poverty and adults with intellectual disabilities
Self-determination has been acknowledged as a criticalconstruct for people with intellectual disability (ID), given the benefits itspromotion entails towards an enhanced quality of life..
High-statistics finite size scaling analysis of U(1) lattice gauge theory with Wilson action
We describe the results of a systematic high-statistics Monte-Carlo study of
finite-size effects at the phase transition of compact U(1) lattice gauge
theory with Wilson action on a hypercubic lattice with periodic boundary
conditions. We find unambiguously that the critical exponent nu is lattice-size
dependent for volumes ranging from 4^4 to 12^4. Asymptotic scaling formulas
yield values decreasing from nu(L >= 4) = 0.33 to nu(L >= 9) = 0.29. Our
statistics are sufficient to allow the study of different phenomenological
scenarios for the corrections to asymptotic scaling. We find evidence that
corrections to a first-order transition with nu=0.25 provide the most accurate
description of the data. However the corrections do not follow always the
expected first-order pattern of a series expansion in the inverse lattice
volume V^{-1}. Reaching the asymptotic regime will require lattice sizes
greater than L=12. Our conclusions are supported by the study of many cumulants
which all yield consistent results after proper interpretation.Comment: revtex, 12 pages, 9 figure
The relationship between ecosystem services and human modification displays decoupling across global delta systems
The ties between a society and its local ecosystem can decouple as societies develop and replace ecosystem services such as food or water regulation via trade and technology. River deltas have developed into important, yet threatened, urban, agricultural and industrial centres. Here, we use global spatial datasets to explore how 49 ecosystem services respond to four human modification indicators, e.g. population density, across 235 large deltas. We formed bundles of statistically correlated ecosystem services and examined if their relationship with modification changed. Decoupling of all robust ecosystem service bundles from at least one modification indicator was indicated in 34% of deltas, while 53% displayed decoupling for at least one bundle. Food-related ecosystem services increased with modification, while the other bundles declined. Our findings suggest two developmental pathways for deltas: as coupled agricultural systems risking irreversible local biodiversity loss; and as decoupled urban centres externalising the impact of their growing demands
Giant crystal-electric-field effect and complex magnetic behavior in single-crystalline CeRh3Si2
Single-crystalline CeRh3Si2 was investigated by means of x-ray diffraction,
magnetic susceptibility, magnetization, electrical resistivity, and specific
heat measurements carried out in wide temperature and magnetic field ranges.
Moreover, the electronic structure of the compound was studied at room
temperature by cerium core-level x-ray photoemission spectroscopy (XPS). The
physical properties were analyzed in terms of crystalline electric field and
compared with results of ab-initio band structure calculations performed within
the density functional theory approach. The compound was found to crystallize
in the orthorhombic unit cell of the ErRh3Si2 type (space group Imma -- No.74,
Pearson symbol: oI24) with the lattice parameters: a = 7.1330(14) A, b =
9.7340(19) A, and c = 5.6040(11) A. Analysis of the magnetic and XPS data
revealed the presence of well localized magnetic moments of trivalent cerium
ions. All physical properties were found to be highly anisotropic over the
whole temperature range studied, and influenced by exceptionally strong
crystalline electric field with the overall splitting of the 4f1 ground
multiplet exceeding 5700 K. Antiferromagnetic order of the cerium magnetic
moments at TN = 4.70(1)K and their subsequent spin rearrangement at Tt =
4.48(1) K manifest themselves as distinct anomalies in the temperature
characteristics of all investigated physical properties and exhibit complex
evolution in an external magnetic field. A tentative magnetic B-T phase
diagram, constructed for B parallel to the b-axis being the easy magnetization
direction, shows very complex magnetic behavior of CeRh3Si2, similar to that
recently reported for an isostructural compound CeIr3Si2. The electronic band
structure calculations corroborated the antiferromagnetic ordering of the
cerium magnetic moments and well reproduced the experimental XPS valence band
spectrum.Comment: 32 pages, 12 figures, to appear in Physical Review
Infrared behavior of the gluon propagator in lattice Landau gauge: the three-dimensional case
We evaluate numerically the three-momentum-space gluon propagator in the
lattice Landau gauge, for three-dimensional pure-SU(2) lattice gauge theory
with periodic boundary conditions. Simulations are done for nine different
values of the coupling , from (strong coupling) to (in the scaling region), and for lattice sizes up to . In the
limit of large lattice volume we observe, in all cases, a gluon propagator
decreasing for momenta smaller than a constant value . From our data
we estimate MeV. The result of a gluon propagator
decreasing in the infrared limit has a straightforward interpretation as
resulting from the proximity of the so-called first Gribov horizon in the
infrared directions.Comment: 14 pages, BI-TP 99/03 preprint, correction in the Acknowledgments
section. To appear in Phys.Rev.
Non-Zero Sum Games for Reactive Synthesis
In this invited contribution, we summarize new solution concepts useful for
the synthesis of reactive systems that we have introduced in several recent
publications. These solution concepts are developed in the context of non-zero
sum games played on graphs. They are part of the contributions obtained in the
inVEST project funded by the European Research Council.Comment: LATA'16 invited pape
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