4,358 research outputs found
Development and validation of the Cannabis Refusal Self-Efficacy Questionnaire (CRSEQ) in adult cannabis users in treatment
Background: There are few valid clinical assessment instruments for cannabis. Self-efficacy, or the ability of users to resist temptation, is a central feature of social cognitive theory. This study outlines the development and validation of the Cannabis Refusal Self-Efficacy Questionnaire (CRSEQ), which measures the situational confidence to refuse cannabis
Semiclassical ionization dynamics of the hydrogen molecular ion in an electric field of arbitrary orientation
Quasi-static models of barrier suppression have played a major role in our
understanding of the ionization of atoms and molecules in strong laser fields.
Despite their success, in the case of diatomic molecules these studies have so
far been restricted to fields aligned with the molecular axis. In this paper we
investigate the locations and heights of the potential barriers in the hydrogen
molecular ion in an electric field of arbitrary orientation. We find that the
barriers undergo bifurcations as the external field strength and direction are
varied. This phenomenon represents an unexpected level of intricacy even on
this most elementary level of the dynamics. We describe the dynamics of
tunnelling ionization through the barriers semiclassically and use our results
to shed new light on the success of a recent theory of molecular tunnelling
ionization as well as earlier theories that restrict the electric field to be
aligned with the molecular axis
Craving mediates the effect of impulsivity on lapse-risk during alcohol use disorder treatment
Rash impulsiveness, the propensity for approach behaviour despite potential negative consequences, is associated with stronger alcohol craving in patients with Alcohol Use Disorder (AUD). This relationship is poorly understood and implications for treatment response are unexamined. This study explored the relationship between rash impulsiveness, craving, and treatment response among 304 outpatients enrolled in a 12-week abstinence-based Cognitive-Behavioural Therapy (CBT) program for AUD. Assessments were completed pre-and-post treatment, with craving and alcohol consumption monitored at each treatment session. Higher rash impulsiveness predicted more frequent craving over treatment (b = 0.95, 95% CI = 0.40, 1.50). Higher craving was associated with greater lapse-risk (b = 0.04, 95% CI = 0.03, 0.05), with the association between craving and lapse-risk increasing as treatment progressed (b = 0.01, 95% CI = 0.01, 0.02). Craving positively mediated the relationship between rash impulsiveness and lapse-risk (µ = 0.38, 95% CI = 0.10, 0.70). Contrary to hypotheses, the risk of lapse in response to craving was not moderated by rash-impulsiveness. These results suggest that AUD patients with a predisposition for rash impulsiveness are more vulnerable to alcohol craving, and subsequently, poorer treatment outcomes
Chandra X-rays from the redshift 7.54 quasar ULAS J1342+0928
We present a 45 ks Chandra observation of the quasar ULAS J1342+0928 at
z=7.54. We detect 14.0^{+4.8}_{-3.7} counts from the quasar in the
observed-frame energy range 0.5-7.0 keV (6-sigma detection), representing the
most distant non-transient astronomical source identified in X-rays to date.
The present data are sufficient only to infer rough constraints on the spectral
parameters. We find an X-ray hardness ratio of HR = -0.51^{+0.26}_{-0.28}
between the 0.5-2.0 keV and 2.0-7.0 keV ranges and derive a power-law photon
index of Gamma = 1.95^{+0.55}_{-0.53}. Assuming a typical value for
high-redshift quasars of Gamma = 1.9, ULAS J1342+0928 has a 2-10 keV rest-frame
X-ray luminosity of L_{2-10} = 11.6^{+4.3}_{-3.5} x 10^{44} erg/s. Its
X-ray-to-optical power-law slope is alpha_{OX}=-1.67^{+0.16}_{-0.10},
consistent with the general trend indicating that the X-ray emission in the
most bolometrically powerful quasars is weaker relative to their optical
emission.Comment: Accepted for publication in the Astrophysical Journal Letter
Short message service (SMS) reminders improve treatment attendance in alcohol dependence, but are less effective for patients high in impulsivity
Background and aims: Poor attendance increases the likelihood of relapse in alcohol dependence treatment. Evidence for improved attendance rates following introduction of short message service (SMS) appointment reminders is available in other health care domains. Patients high in impulsivity, characterized by a lack of planning, may particularly benefit from reminders. The study investigated the impact of SMS reminders on outpatient treatment attendance for alcohol dependence, and whether effects were moderated by impulsivity. Design: Prospective natural history study, with historical case control. Alcohol-dependent outpatients attending treatment received SMS appointment reminders (n = 102). These were compared to a historical control group (n = 91) treated prior to the introduction of SMS (totalling 1149 scheduled sessions). Setting: A metropolitan university hospital alcohol and drug outpatient clinic. Participants: 193 alcohol-dependent patients participated in a 12-week cognitive-behavioral therapy (CBT) program with a treatment goal of abstinence. Measurements: Trait impulsivity, severity of dependence, psychological distress at baseline. Attendance at each scheduled session. Findings: SMS reminders significantly increased probability of session attendance (0.90 versus 0.84, p =.02). The effect was qualified by a significant SMS x Impulsivity interaction whereby reminders became less effective with increasing patient impulsivity (p =.003). Conclusions: SMS appointment reminders improve treatment attendance for alcohol-dependent outpatients. More impulsive patients benefited less from reminders, suggesting their non-attendance may be related more to motivational factors
Metabolic syndrome components and their response to lifestyle and metformin interventions are associated with differences in diabetes risk in persons with impaired glucose tolerance
Aims
To determine the association of metabolic syndrome (MetS) and its components with diabetes risk in participants with impaired glucose tolerance (IGT), and whether intervention-related changes in MetS lead to differences in diabetes incidence. Methods
We used the National Cholesterol Education Program/Adult Treatment Panel III (NCEP/ATP III) revised MetS definition at baseline and intervention-related changes of its components to predict incident diabetes using Cox models in 3234 Diabetes Prevention Program (DPP) participants with IGT over an average follow-up of 3.2 years. Results
In an intention-to-treat analysis, the demographic-adjusted hazard ratios (95% confidence interval) for diabetes in those with MetS (vs. no MetS) at baseline were 1.7 (1.3–2.3), 1.7 (1.2–2.3) and 2.0 (1.3–3.0) for placebo, metformin and lifestyle groups, respectively. Higher levels of fasting plasma glucose and triglycerides at baseline were independently associated with increased risk of diabetes. Greater waist circumference (WC) was associated with higher risk in placebo and lifestyle groups, but not in the metformin group. In a multivariate model, favourable changes in WC (placebo and lifestyle) and high-density lipoprotein cholesterol (placebo and metformin) contributed to reduced diabetes risk. Conclusions
MetS and some of its components are associated with increased diabetes incidence in persons with IGT in a manner that differed according to DPP intervention. After hyperglycaemia, the most predictive factors for diabetes were baseline hypertriglyceridaemia and both baseline and lifestyle-associated changes in WC. Targeting these cardiometabolic risk factors may help to assess the benefits of interventions that reduce diabetes incidence
Social cognitive predictors of treatment outcome in cannabis dependence
Background Drug-related outcomes expectancies and refusal self-efficacy are core components of Social Cognitive Theory. Both predict treatment outcome in alcohol use disorders. Few studies have reported expectancies and refusal self-efficacy in cannabis dependence. None have examined both, although both constructs are key targets in Cognitive-Behavioural Therapy (CBT). This study tests the predictive role of expectancies and refusal self-efficacy in treatment outcome for cannabis dependence. Design Outpatients completed a comprehensive assessment when commencing cannabis treatment and predictors of treatment outcome were tested. Setting A university hospital alcohol and drug outpatient clinic. Participants 221 cannabis-dependent patients participated in a 6-week CBT program where the goal was abstinence. Measurements Cannabis Expectancy Questionnaire and Cannabis Refusal Self-Efficacy Questionnaire, cannabis dependence severity [Severity of Dependence Scale], psychological distress [General Health Questionnaire] at baseline; the timeline follow-back procedure at baseline and each session. Findings Patients reporting lower confidence in their ability to resist cannabis during high negative affect (emotional relief refusal self-efficacy) had a lower likelihood of abstinence (p\ua0=\ua00.004), more days of use (p\ua
Treatment seeking in cannabis dependence: the role of social cognition
Background and aims Relatively few cannabis dependent individuals seek treatment and little is known about the determinants of treatment seeking. Social Cognitive Theory (SCT) provides a useful framework for examining human behaviour and motivation which may be helpful in explaining treatment seeking. This study examined the differences in cannabis outcome expectancies and cannabis refusal self-efficacy between treatment seekers and non-treatment seekers with cannabis dependence. Design Non-treatment seekers were referred to an illicit drug diversion program. Treatment seekers commenced an outpatient cannabis treatment program and completed a comprehensive assessment that included measures of cannabis outcome expectancies and refusal self-efficacy. Setting A public hospital alcohol and drug outpatient clinic. Participants 269 non-treatment seekers and 195 individuals commencing cannabis dependence treatment. Measurements The Cannabis Expectancy Questionnaire (CEQ), Cannabis Refusal Self-Efficacy Questionnaire (CRSEQ), Severity of Dependence Scale – Cannabis (SDS-C), General Health Questionnaire (GHQ-28) and Readiness to Change Questionnaire (RTC) were completed. Findings Treatment seekers had significantly higher levels of negative cannabis outcome expectancies and significantly lower levels of emotional relief refusal self-efficacy (belief in ability to resist using cannabis when experiencing negative affect) (ps < 0.001). Treatment seekers had significantly higher levels of psychological distress and self-perceived cannabis dependence compared to non-treatment seekers (ps < 0.001). Conclusions High negative cannabis outcome expectancies and low emotional relief refusal self-efficacy may play a key role in motivation to seek treatment
Numerical simulations of a non-commutative theory: the scalar model on the fuzzy sphere
We address a detailed non-perturbative numerical study of the scalar theory
on the fuzzy sphere. We use a novel algorithm which strongly reduces the
correlation problems in the matrix update process, and allows the investigation
of different regimes of the model in a precise and reliable way. We study the
modes associated to different momenta and the role they play in the ``striped
phase'', pointing out a consistent interpretation which is corroborated by our
data, and which sheds further light on the results obtained in some previous
works. Next, we test a quantitative, non-trivial theoretical prediction for
this model, which has been formulated in the literature: The existence of an
eigenvalue sector characterised by a precise probability density, and the
emergence of the phase transition associated with the opening of a gap around
the origin in the eigenvalue distribution. The theoretical predictions are
confirmed by our numerical results. Finally, we propose a possible method to
detect numerically the non-commutative anomaly predicted in a one-loop
perturbative analysis of the model, which is expected to induce a distortion of
the dispersion relation on the fuzzy sphere.Comment: 1+36 pages, 18 figures; v2: 1+55 pages, 38 figures: added the study
of the eigenvalue distribution, added figures, tables and references, typos
corrected; v3: 1+20 pages, 10 eps figures, new results, plots and references
added, technical details about the tests at small matrix size skipped,
version published in JHE
The Discovery of a Highly Accreting, Radio-loud Quasar at z = 6.82
Radio sources at the highest redshifts can provide unique information on the first massive galaxies and black holes, the densest primordial environments, and the epoch of reionization. The number of astronomical objects identified at z > 6 has increased dramatically over the last few years, but previously only three radio-loud (R 2500 = f ν,5 GHz/f ν,2500 Å > 10) sources had been reported at z > 6, with the most distant being a quasar at z = 6.18. Here we present the discovery and characterization of PSO J172.3556+18.7734, a radio-loud quasar at z = 6.823. This source has an Mg ii-based black hole mass of ∼3 × 108 M o˙ and is one of the fastest accreting quasars, consistent with super-Eddington accretion. The ionized region around the quasar is among the largest measured at these redshifts, implying an active phase longer than the average lifetime of the z ⪆ 6 quasar population. From archival data, there is evidence that its 1.4 GHz emission has decreased by a factor of two over the last two decades. The quasar's radio spectrum between 1.4 and 3.0 GHz is steep (α = -1.31). Assuming the measured radio slope and extrapolating to rest-frame 5 GHz, the quasar has a radio-loudness parameter R 2500 ∼ 90. A second steep radio source (α = -0.83) of comparable brightness to the quasar is only 23.″1 away (∼120 kpc at z = 6.82; projection probability <2%), but shows no optical or near-infrared counterpart. Further follow-up is required to establish whether these two sources are physically associated
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