838 research outputs found
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Cognitive Bias Modification Training & Exercise: For Alleviating Depression, Anxiety & Stress Related Disorders
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Two Session Cognitive Bias Modification Training; Exercise Interpretation Bias
Cognitive bias modification is the direct manipulation of a target bias by extensive exposure to task contingencies that encourage predetermined patterns of processing selectivity1,2. Forty-eight participants from a general population sample recruited for a two-part study investigating the effect of two sessions of exercise orientated Positive CBM-I Training, in comparison to a Neutral Pseudo Training condition. Baseline, post session one and post session two self-report measures of Anxiety, Depression and Stress were collected. Measures of interpretation bias were collected at baseline and post session two, both with and without cognitive load. Results suggest that for individuals undergoing two sessions of Positive CBM-I Training over a fortnight had significantly decreased Trait Anxiety scores, relative to the Pseudo Neutral Training condition. The findings hold promise for the Cognitive Bias Modification paradigm for decreasing symptoms of Anxiety
Interdecadal changes in the community, population and individual levels of the fish fauna of an extensively modified estuary
This study examined inter-period changes over two to three decades in the fish fauna of an urbanized estuary experiencing rapid population growth and a drying climate (Swan-Canning Estuary, Western Australia). Responses were compared at the fish community level (species composition; 1978-2009 in the shallows and 1993-2009 in deeper waters) and at the population and individual levels of an estuarine indicator species, black bream Acanthopagrus butcheri (biomass-abundance and per capita mass at age, respectively; 1993-2009). All three levels showed distinct shifts from earlier to later periods, but their patterns, sensitivity and breadth differed. Community composition changed markedly in the shallows of the lower-middle estuary between the late 1970s and all later periods and moderately between more disparate periods from 1995 to 2009. Several species trends could be linked to the increasing salinity of the estuary or declining dissolved oxygen levels in its middle-upper reaches. Community changes were, however, small or insignificant in the shallow and deeper waters of the upper estuary and deeper waters of the middle estuary, where environmental perturbations are often most pronounced. This may reflect the resilience of the limited suite of species that typify those reaches and thus their lack of sensitivity in reflecting longer-term change at the coarser level of mean abundance. One such species, the selected indicator, A. butcheri, did, however, show marked temporal changes at both the population and individual levels. Biomass decreased markedly in deeper waters while increasing in the shallows from earlier to later periods, presumably reflecting an onshore movement of fish, and per capita body mass in the 2+, 3+ and 4+ year classes fell steadily over time. Such changes probably indicate deteriorating habitat quality in the deeper waters. The study outcomes provide support for a multifaceted approach to the biomonitoring of estuaries using fishes and highlight the need for complementary monitoring of relevant stressors to better disentangle cause-effect pathways
Characteristics of the ichthyofauna of a temperate microtidal estuary with a reverse salinity gradient, including inter-decadal comparisons
Data on the fish fauna of the Leschenault Estuary on the lower west coast of Australia were collected and used as a model to elucidate the characteristics of permanently open estuaries with a reverse salinity gradient, which undergo seasonal changes similar to many other estuaries with Mediterranean climate. Focus was placed on determining (1) the relationships of the number of species, density, life cycle category and species composition of fishes with region (within estuary), season and year and salinity, (2) whether species are partitioned along the lengths of such systems and (3) the extent and significance of any inter-decadal changes in species composition. The analyses and interpretation involved using multi-factorial permutational multivariate analysis of variance (PERMANOVA) and analysis of similarity (ANOSIM) designs, and three new or recently published visualization tools, i.e. modified non-metric multidimensional scaling (nMDS) plots, coherent species curves and segmented bubble plots. The base, lower, upper and apex regions of the Leschenault Estuary, along which the salinity increased in each season except in winter when most rainfall occurs, were sampled seasonally for the 2 years between winter 2008 and autumn 2010. Estuarine residents contributed twice as many individuals, but less than half the number of species as marine taxa. While the numbers of marine species and estuarine residents declined between the base or lower and apex regions, the individuals of marine species dominated the catches in the base region and estuarine residents in the other three regions. Ichthyofaunal composition in each region underwent conspicuous annual cyclical changes, due to time-staggered differences in recruitment among species, and changed sequentially along the estuary, both paralleling salinity trends. Different groups of species characterized the fauna in the different regions and seasons, thereby partitioning resources among species. The ichthyofauna of the apex region, in which salinities reached 54 and temperatures 36° C, recorded the highest maximum density and, in terms of abundance, was dominated (90%) by three atherinid species, emphasizing the ability of this family to tolerate extreme conditions. Comparisons between the data for 2008-2010 and 1994 demonstrate that the spotted hardyhead Craterocephalus mugiloides and the common hardyhead Atherinomorus vaigiensis had colonized and become abundant in the Leschenault Estuary in the intervening period. This represents a southwards extension of the distribution of these essentially tropical species during a period of increasing coastal water temperatures as a result of climate change. The abundance of weed-associated species, e.g. the western gobbleguts Ostorhinchus rueppellii and the soldier Gymnapistes marmoratus, increased, whereas that of the longfinned goby Favonigobius lateralis decreased, probably reflecting increases in eutrophication and siltation, respectively
Aerial Survey Estimates of Abundance of the Eastern Chukchi Sea Stock of Beluga Whales (Delphinapterus leucas) in 2012
The eastern Chukchi Sea (ECS) stock of beluga whales is one of three stocks in western Alaska that are co-managed by the National Marine Fisheries Service and the Alaska Beluga Whale Committee. Abundance of this stock was estimated as 3710 in 1991 from incomplete data. Analysis of data from satellite-linked time-depth recorders (SDRs) attached to belugas in summer concentration areas of the ECS and Beaufort Sea (BS) stocks provided an overview of beluga distribution and movements and allowed the identification of an area (140Ë W to 157Ë W in the BS) and a time period (19 July â 20 August) in which the distributions of the two stocks do not overlap. Aerial survey data were collected by the Aerial Surveys of Arctic Marine Mammals (ASAMM) project in that region and time period in 2012. We used those data in a line transect analysis that estimated there were 5547 (CV = 0.22) surface-visible belugas in the study area. Data from SDRs were used to develop correction factors to account for animals that were missed because they were either outside of the study area or diving too deep to be seen, resulting in a total abundance estimate of 20 752 (CV = 0.70). The average annual Alaska Native subsistence harvest from the ECS stock (57) is about 0.3% of the population estimate. Without data collected by the ASAMM project and from satellite-linked tags, this analysis would not have been possible. Additional surveys and tagging of ECS belugas are warranted.Le stock de bĂ©lugas de lâest de la mer des Tchouktches (EMT) figure parmi les trois stocks de lâouest de lâAlaska Ă ĂȘtre gĂ©rĂ©s conjointement par le National Marine Fisheries Service et lâAlaska Beluga Whale Committee. Ă partir de donnĂ©es incomplĂštes, lâabondance de ce stock a Ă©tĂ© estimĂ©e Ă 3 710 en 1991. Lâanalyse des donnĂ©es recueillies Ă lâaide dâenregistreurs de profondeur temporelle satellitaires (SDR) fixĂ©s aux bĂ©lugas dans les zones de concentration estivales de lâEMT et de la mer de Beaufort (MB) a permis dâobtenir un aperçu de la rĂ©partition et du dĂ©placement des bĂ©lugas ainsi que de cerner une zone (de 140Ë O Ă 157Ë O dans la MB) et une pĂ©riode (du 19 juillet au 20 aoĂ»t) pour lesquelles la rĂ©partition des deux stocks ne se chevauchent pas. Le projet Aerial Surveys of Arctic Marine Mammals (ASAMM) a permis de recueillir des donnĂ©es Ă partir de levĂ©s aĂ©riens pour la rĂ©gion et la pĂ©riode concernĂ©es en 2012. GrĂące Ă une analyse de lignes interceptĂ©es, ces donnĂ©es ont permis dâestimer quâil y avait 5 547 (CV = 0,22) bĂ©lugas visibles Ă la surface dans la zone Ă lâĂ©tude. Les donnĂ©es en provenance de SDR ont servi Ă mettre au point des facteurs de correction pour tenir compte des bĂ©lugas qui nâont pas Ă©tĂ© captĂ©s, soit parce quâils se trouvaient en dehors de la zone visĂ©e par lâĂ©tude, soit parce quâils plongeaient trop loin pour ĂȘtre vus, ce qui sâest traduit par une estimation totale dâabondance de 20 752 (CV = 0,70) bĂ©lugas. La prise de subsistance annuelle moyenne de stock (57) par les Autochtones de lâAlaska dans lâEMT correspond Ă environ Ă 0,3 % de lâestimation de la population. Cette analyse nâaurait pu ĂȘtre possible sans les donnĂ©es prĂ©levĂ©es par le projet ASAMM et les SDR. Dâautres levĂ©s et lâĂ©tiquetage des bĂ©lugas de lâEMT sâimposent
An almost sure limit theorem for super-Brownian motion
We establish an almost sure scaling limit theorem for super-Brownian motion
on associated with the semi-linear equation , where and are positive constants. In
this case, the spectral theoretical assumptions that required in Chen et al
(2008) are not satisfied. An example is given to show that the main results
also hold for some sub-domains in .Comment: 14 page
Generation of Porous Particle Structures using the Void Expansion Method
The newly developed "void expansion method" allows for an efficient
generation of porous packings of spherical particles over a wide range of
volume fractions using the discrete element method. Particles are randomly
placed under addition of much smaller "void-particles". Then, the void-particle
radius is increased repeatedly, thereby rearranging the structural particles
until formation of a dense particle packing.
The structural particles' mean coordination number was used to characterize
the evolving microstructures. At some void radius, a transition from an
initially low to a higher mean coordination number is found, which was used to
characterize the influence of the various simulation parameters. For structural
and void-particle stiffnesses of the same order of magnitude, the transition is
found at constant total volume fraction slightly below the random close packing
limit. For decreasing void-particle stiffness the transition is shifted towards
a smaller void-particle radius and becomes smoother.Comment: 9 pages, 8 figure
Large Kinetic Power in FRII Radio Jets
We investigate the total kinetic powers (L_{j}) and ages (t_{age}) of
powerful jets of four FR II radio sources (Cygnus A, 3C 223, 3C 284, and 3C
219) by the detail comparison of the dynamical model of expanding cocoons with
observed ones. It is found that these sources have quite large kinetic powers
with the ratio of L_{j} to the Eddington luminosity (L_{Edd}) resides in . Reflecting the large kinetic powers, we also find that the
total energy stored in the cocoon (E_{c}) exceed the energy derived from the
minimum energy condition (E_{min}): . This implies that
a large amount of kinetic power is carried by invisible components such as
thermal leptons (electron and positron) and/or protons.Comment: 5 pages, accepted for publication in Astrophysics and Space Scienc
Assume-Guarantee Abstraction Refinement for Probabilistic Systems
We describe an automated technique for assume-guarantee style checking of
strong simulation between a system and a specification, both expressed as
non-deterministic Labeled Probabilistic Transition Systems (LPTSes). We first
characterize counterexamples to strong simulation as "stochastic" trees and
show that simpler structures are insufficient. Then, we use these trees in an
abstraction refinement algorithm that computes the assumptions for
assume-guarantee reasoning as conservative LPTS abstractions of some of the
system components. The abstractions are automatically refined based on tree
counterexamples obtained from failed simulation checks with the remaining
components. We have implemented the algorithms for counterexample generation
and assume-guarantee abstraction refinement and report encouraging results.Comment: 23 pages, conference paper with full proof
Statistics of the contact network in frictional and frictionless granular packings
Simulated granular packings with different particle friction coefficient mu
are examined. The distribution of the particle-particle and particle-wall
normal and tangential contact forces P(f) are computed and compared with
existing experimental data. Here f equivalent to F/F-bar is the contact force F
normalized by the average value F-bar. P(f) exhibits exponential-like decay at
large forces, a plateau/peak near f = 1, with additional features at forces
smaller than the average that depend on mu. Computations of the force-force
spatial distribution function and the contact point radial distribution
function indicate that correlations between forces are only weakly dependent on
friction and decay rapidly beyond approximately three particle diameters.
Distributions of the particle-particle contact angles show that the contact
network is not isotropic and only weakly dependent on friction. High
force-bearing structures, or force chains, do not play a dominant role in these
three dimensional, unloaded packings.Comment: 11 pages, 13 figures, submitted to PR
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