5,176 research outputs found
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Plethodon stormi
Number of Pages: 2Integrative BiologyGeological Science
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Plethodon elongatus
Number of Pages: 2Integrative BiologyGeological Science
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Taricha torosa
Number of Pages: 4Integrative BiologyGeological Science
Effect of closing facilities on electroconvulsive therapy use in Glasgow
<p>Objectives: To assess the effect of closure of electroconvulsive therapy (ECT) centers on ECT use. Electroconvulsive therapy remains a recommended and effective treatment for mental disorders. Declining rates
of ECT use in the United Kingdom have been observed over the last 20 years with anecdotal observations that use has declined as the result of centralization of provision. In Glasgow, there have been site closures in the north with no such rationing taking place in the south.</p>
<p>Methods: A naturalistic retrospective survey of the number of ECT
courses commenced each year in Glasgow, with a comparison made between the north and the south of the city. Data were available from 1996 to 2008.</p>
<p>Results: Our analysis showed no change in the mean number of ECT courses commenced in southern AQ2 Glasgow (period 1, 42.25; period 2, 41.83; period 3, 31; F = 1.369; P = 0.298). There was a signiļ¬cant reduction in the mean number of ECT treatments commenced in northern Glasgow (period 1, 91.25; period 2, 51; period 3, 33.33; F = 10.06; P = 0.04).</p>
<p>Conclusions: In northern Glasgow, where there have been 2 site closures since 1996, ECT use has declined. This trend was not replicated in the south of the city. This would suggest that the closure of ECT centers does reduce the use of ECT. However, there may be a number of confounding variables that could not be factored into the analysis because of lack of available data.</p>
IUCN Redlist Assessment of Placostylus fulguratus
This species is assessed as Least Concern. It is relatively common and found relatively easily at several different and widespread locations on Viti Levu, within its known geographical range. More research is needed to determine its current occurrence on Vanua Levu, Ovalau and Beqa. The population of this species should be monitored for any potential future impacts of invasive species or collection
On āOrganized Crimeā in the illicit antiquities trade: moving beyond the definitional debate
The extent to which āorganized crimeā is involved in illicit antiquities trafficking is unknown and frequently debated. This paper explores the significance and scale of the illicit antiquities trade as a unique transnational criminal phenomenon that is often said to be perpetrated by and exhibit traits of so-called āorganized crime.ā The definitional debate behind the term āorganized crimeā is considered as a potential problem impeding our understanding of its existence or extent in illicit antiquities trafficking, and a basic progression-based model is then suggested as a new tool to move beyond the definitional debate for future research that may help to elucidate the actors, processes and criminal dynamics taking place within the illicit antiquities trade from source to market. The paper concludes that researchers should focus not on the question of whether organized criminals- particularly in a traditionally conceived, mafia-type stereotypical sense- are involved in the illicit antiquities trade, but instead on the structure and progression of antiquities trafficking itself that embody both organized and criminal dynamics
Phenotypic Mismatches Reveal Escape from Arms-Race Coevolution
Because coevolution takes place across a broad scale of time and space, it is virtually impossible to understand its dynamics and trajectories by studying a single pair of interacting populations at one time. Comparing populations across a range of an interaction, especially for long-lived species, can provide insight into these features of coevolution by sampling across a diverse set of conditions and histories. We used measures of prey traits (tetrodotoxin toxicity in newts) and predator traits (tetrodotoxin resistance of snakes) to assess the degree of phenotypic mismatch across the range of their coevolutionary interaction. Geographic patterns of phenotypic exaggeration were similar in prey and predators, with most phenotypically elevated localities occurring along the central Oregon coast and central California. Contrary to expectations, however, these areas of elevated traits did not coincide with the most intense coevolutionary selection. Measures of functional trait mismatch revealed that over one-third of sampled localities were so mismatched that reciprocal selection could not occur given current trait distributions. Estimates of current locality-specific interaction selection gradients confirmed this interpretation. In every case of mismatch, predators were āaheadā of prey in the arms race; the converse escape of prey was never observed. The emergent pattern suggests a dynamic in which interacting species experience reciprocal selection that drives arms-race escalation of both prey and predator phenotypes at a subset of localities across the interaction. This coadaptation proceeds until the evolution of extreme phenotypes by predators, through genes of large effect, allows snakes to, at least temporarily, escape the arms race
Sparse and stable Markowitz portfolios
We consider the problem of portfolio selection within the classical Markowitz
mean-variance framework, reformulated as a constrained least-squares regression
problem. We propose to add to the objective function a penalty proportional to
the sum of the absolute values of the portfolio weights. This penalty
regularizes (stabilizes) the optimization problem, encourages sparse portfolios
(i.e. portfolios with only few active positions), and allows to account for
transaction costs. Our approach recovers as special cases the
no-short-positions portfolios, but does allow for short positions in limited
number. We implement this methodology on two benchmark data sets constructed by
Fama and French. Using only a modest amount of training data, we construct
portfolios whose out-of-sample performance, as measured by Sharpe ratio, is
consistently and significantly better than that of the naive evenly-weighted
portfolio which constitutes, as shown in recent literature, a very tough
benchmark.Comment: Better emphasis of main result, new abstract, new examples and
figures. New appendix with full details of algorithm. 17 pages, 6 figure
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