20,507 research outputs found
Gambling in Great Britain:a response to Rogers
A recent issue of Practice: Social Work in Action featured a paper by Rogers that examined whether the issue of problem gambling was a suitable case for social work. Rogers’ overview was (in various places) out of date, highly selective, contradictory, presented unsupported claims and somewhat misleading. Rogers’ paper is to be commended for putting the issue of problem gambling on the social work agenda. However, social workers need up-to-date information and contextually situated information if they are to make informed decisions in helping problem gamblers
Cosmic Gravitational Shear from the HST Medium Deep Survey
We present a measurement of cosmic shear on scales ranging from 10\arcsec
to 2\arcmin in 347 WFPC2 images of random fields. Our result is based on
shapes measured via image fitting and on a simple statistical technique;
careful calibration of each step allows us to quantify our systematic
uncertainties and to measure the cosmic shear down to very small angular
scales. The WFPC2 images provide a robust measurement of the cosmic shear
signal decreasing from at 10\arcsec to at 130\arcsec .Comment: 4 pages 2 Postscript figures, uses emulateapj.cls Astrophysical
Journal Letters, December 1, 200
How do impulsivity traits influence problem gambling through gambling motives? The role of perceived gambling risk/benefits.
Although substantial research suggests that motivations have been found to mediate the relationships between impulsivity traits and various forms of substance use, no studies have examined how gambling motives may mediate the relationships between impulsivity traits and problem gambling. The primary purpose of this study was to test an integrative model linking impulsivity traits and gambling problems, evaluating the mediating effects of gambling motives. Participants were 594 students (73% male; mean age =19.92; SD=2.91) enrolled in public high schools or universities. Young people who tend to act rashly in response to extremely positive moods, showed higher enhancement and coping motives, which in turn were positively related to gambling problems. Individuals with higher levels of sensation seeking were more likely to have higher levels of enhancement motives, which in turn were also positively related to gambling problems. The model was examined in several groups, separately for the level of perceived gambling risk/benefits (lower perceived gambling risk, higher perceived gambling risk, lower perceived gambling benefits, and higher perceived gambling benefits). There were significant differences between these groups for this division. These findings suggest that prevention and/or treatment strategies might want to consider the model’s variables, including impulsivity traits and gambling motives, in accordance with individual levels of perceived gambling risk/benefits
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Buddhist-Derived Loving-Kindness and Compassion Meditation for the Treatment of Psychopathology: a Systematic Review
Although clinical interest has predominantly focused on mindfulness meditation, interest into the clinical utility of Buddhist-derived loving-kindness meditation (LKM) and compassion meditation (CM) is also growing. This paper follows the PRISMA (preferred reporting items for systematic reviews and meta-analysis) guidelines and provides an evaluative systematic review of LKM and CM intervention studies. Five electronic academic databases were systematically searched to identify all intervention studies assessing changes in the symptom severity of Diagnostic and Statistical Manual of Mental Disorders (text revision fourth edition) Axis I disorders in clinical samples and/or known concomitants thereof in sub-clinical/healthy samples. The comprehensive database search yielded 342 papers and 20 studies (comprising a total of 1,312 participants) were eligible for inclusion. The Quality Assessment Tool for Quantitative Studies was then used to assess study quality. Participants demonstrated significant improvements across five psychopathology-relevant outcome domains: (i) positive and negative affect, (ii) psychological distress, (iii) positive thinking, (iv) interpersonal relations, and (v) empathic accuracy. It is concluded that LKM and CM interventions may have utility for treating a variety of psychopathologies. However, to overcome obstacles to clinical integration, a lessons-learned approach is recommended whereby issues encountered during the (ongoing) operationalization of mindfulness interventions are duly considered. In particular, there is a need to establish accurate working definitions for LKM and CM
Carbon Nanotubes in Helically Modulated Potentials
We calculate effects of an applied helically symmetric potential on the low
energy electronic spectrum of a carbon nanotube in the continuum approximation.
The spectrum depends on the strength of this potential and on a dimensionless
geometrical parameter, P, which is the ratio of the circumference of the
nanotube to the pitch of the helix. We find that the minimum band gap of a
semiconducting nanotube is reduced by an arbitrarily weak helical potential,
and for a given field strength there is an optimal P which produces the biggest
change in the band gap. For metallic nanotubes the Fermi velocity is reduced by
this potential and for strong fields two small gaps appear at the Fermi surface
in addition to the gapless Dirac point. A simple model is developed to estimate
the magnitude of the field strength and its effect on DNA-CNT complexes in an
aqueous solution. We find that under typical experimental conditions the
predicted effects of a helical potential are likely to be small and we discuss
several methods for increasing the size of these effects.Comment: 12 pages, 10 figures. Accepted for publication in Physical Review B.
Image quality reduced to comply with arxiv size limitation
Weak Lensing Determination of the Mass in Galaxy Halos
We detect the weak gravitational lensing distortion of 450,000 background
galaxies (20<R<23) by 790 foreground galaxies (R<18) selected from the Las
Campanas Redshift Survey (LCRS). This is the first detection of weak lensing by
field galaxies of known redshift, and as such permits us to reconstruct the
shear profile of the typical field galaxy halo in absolute physical units
(modulo H_0), and to investigate the dependence of halo mass upon galaxy
luminosity. This is also the first galaxy-galaxy lensing study for which the
calibration errors are negligible. Within a projected radius of 200 \hkpc, the
shear profile is consistent with an isothermal profile with circular velocity
164+-20 km/s for an L* galaxy, consistent with typical disk rotation at this
luminosity. This halo mass normalization, combined with the halo profile
derived by Fischer et al (2000) from lensing analysis SDSS data, places a lower
limit of (2.7+-0.6) x 10^{12}h^{-1} solar masses on the mass of an L* galaxy
halo, in good agreement with satellite galaxy studies. Given the known
luminosity function of LCRS galaxies, and the assumption that for galaxies, we determine that the mass within 260\hkpc of normal
galaxies contributes to the density of the Universe (for
) or for . These lensing data suggest
that (95% CL), only marginally in agreement with the usual
Faber-Jackson or Tully-Fisher scaling. This is the most
complete direct inventory of the matter content of the Universe to date.Comment: 18 pages, incl. 3 figures. Submitted to ApJ 6/7/00, still no response
from the referee after four months
Networking strategies in streptomyces coelicolor
We are interested the soil dwelling bacteria Streptomyces coelicolor because its cells grow end to end in a line. New branches have the potential to extend from any point along this line and the result is a network of branches and connections. This is a novel form of colonisation in the bacterial world and it is advantageous for spreading through an environment resourcefully. Networking protocols for communication technologies have similar pressures to be resourceful in terms of time, computing power, and energy. In this preliminary investigation we design a computer model of the biological system to understand its limitations and strategies for survival. The decentralised capacity for organisation of both the bacterial system and the model reflects well on the now-popular conventions for path finding and ad hoc network building in human technologies. The project will ultimately become a comparison of strategies between nature and the man-made
Cosmological Reionization by Stellar Sources
I use cosmological simulations that incorporate a physically motivated
approximation to three-dimensional radiative transfer that recovers correct
asymptotic ionization front propagation speeds for some cosmologically relevant
density distributions transfer to investigate the process of the reionization
of the universe by ionizing radiation from proto-galaxies. Reionization
proceeds in three stages and occupies a large redshift range from z~15 until
z~5. During the first, ``pre-overlap'' stage, HII regions gradually expand into
the low density IGM, leaving behind neutral high density protrusions. During
the second, ``overlap'' stage, that occurs in about 10% of the Hubble time, HII
regions merge and the ionizing background rises by a large factor. During the
third, ``post-overlap'' stage, remaining high density regions are being
gradually ionized as the required ionizing photons are being produced.
Residual fluctuations in the ionizing background reach significant (more than
10%) levels for the Lyman-alpha forest absorption systems with column densities
above 10^14 - 10^15 cm^-2 at z=3 to 4.Comment: Revised version accepted for publication in ApJ. Color versions of
Fig. 3a-h in GIF format, full (unbinned) versions of Fig. 5, 6, and 13, as
well as MPEG animations are available at
http://casa.colorado.edu/~gnedin/GALLERY/rei_p.htm
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