21,468 research outputs found
The role of stress-reactivity, stress-recovery and risky decision-making in psychosocial stress-induced alcohol consumption in social drinkers
Rationale
Chronic alcohol misuse can escalate into alcohol use disorder (AUD). The causal mechanisms through
which recreational social drinking develops into compulsive uncontrolled alcohol misuse are
multifaceted. For example, stress is an important risk factor that influences alcohol craving in both
healthy and addicted individuals. In addition, those that are high in impulsivity/risk taking drink more
and are at greater risk of developing addiction. At present, however, it is not possible accurately to
predict those at risk of escalation in alcohol use, or of developing AUD.
Objectives
The aim of this study was to investigate how underlying physiological and personality traits affect
stress-induced craving for, and consumption of, alcohol, in a sample of healthy social drinkers. The
primary hypothesis was that impulsivity/risk-taking would modulate stress-induced alcohol craving
and consumption.
Methods
Thirty-nine participants (22 male and 17 female; mean age = 23.92 years [SD = 4.90]) were randomly
allocated to “stress” and “no-stress” groups; in the stress group participants took part in the Trier
Social Stress Test (TSST). Participants completed several questionnaires and computer tasks in order
to assess prior alcohol use, impulsivity/risk-taking, stress-reactivity, craving and physiological
biomarkers of stress. Finally, participants completed a voluntary drinking task, in which increasing
numbers of presses on a computer keyboard were reinforced with 5ml shots of 37% ABV vodka (plus
mixer).
Results
Participants exposed to the TSST showed an increase in craving following the stressor. Several
factors predicted voluntary drinking, including risky decision making, slow HR recovery from stress,
poor vagal tone during recovery from stress and greater stress reactivity. Surprisingly, we found no
correlation between craving and consumption.
Conclusions
Our data suggest that variation in physiological stress parameters and poor decision-making abilities
increase risk of stress-induced alcohol consumption. This may provide a useful translational
framework through which we can further study early predictive markers for the shift between
controlled recreational drinking to uncontrolled alcohol misuse, including AUD
Adolescents care but don't feel responsible for farm animal welfare
Adolescents are the next generation of consumers with the potential to raise standards of farm animal welfare—to theirsatisfaction—if their preferences and concerns are translated into accurate market drivers and signals. There are no published data about adolescent views of farm animal welfare to allow meaningful design, implementation, and evaluation of educational strategies to improve consideration of—and behavior toward—farm animals. Knowledge of farm animal welfare, as well as beliefs and attitudes about farm animal welfare and behavioral intention relevant to it were determined in a sample of ukadolescents, using a survey incorporating an extended version of the theory of planned behavior and novel assessment tools. Our results indicate that adolescents have only a limited knowledge of welfare problems for farm animals and welfare-relevant product labels. Intentions to identify welfare standards for the animals from whom their food was derived were weak. Although they cared about farm animal welfare and agreed with fundamental principles—for example, the provision of space and the absence of pain and suffering—like adults they held limited belief in the power and responsibility that they possess through their choices as consumers; responsibility was often shifted to others, such as the government and farmers
Optimal eigenvalue estimate for the Dirac-Witten operator on bounded domains with smooth boundary
Eigenvalue estimate for the Dirac-Witten operator is given on bounded domains
(with smooth boundary) of spacelike hypersurfaces satisfying the dominant
energy condition, under four natural boundary conditions (MIT, APS, modified
APS, and chiral conditions). This result is a generalisation of Friedrich's
inequality for the usual Dirac operator. The limiting cases are also
investigated.Comment: 2007, 18 pages, submitted 02 June 200
Hole density dependence of effective mass, mobility and transport time in strained Ge channel modulation-doped heterostructures
We performed systematic low-temperature (T = 350 mK–15 K) magnetotransport measurements on the two-dimensional hole gas with various sheet carrier densities Ps = (0.57–2.1)×1012 cm–2 formed in the strained Ge channel modulation-doped (MOD) SiGe heterostructures grown on Si substrates. It was found that the effective hole mass deduced by temperature dependent Shubnikov–de Hass oscillations increased monotonically from (0.087±0.05)m0 to (0.19±0.01)m0 with the increase of Ps, showing large band nonparabolicity in strained Ge. In contrast to this result, the increase of the mobility with increasing Ps (up to 29 000 cm2/V s) was observed, suggesting that Coulomb scattering played a dominant role in the transport of the Ge channel at low temperatures. In addition, the Dingle ratio of the transport time to the quantum lifetime was found to increase with increasing Ps, which was attributed to the increase of remote impurity scattering with the increase of the doping concentration in MOD SiGe layers
Wave function-dependent mobility and suppression of interface roughness scattering in a strained SiGe p-channel field-effect structure
The 4 K Hall mobility has been measured in a top-gated, inverted, modulation-doped Si/Si0.8Ge0.2 structure having a Si:B doping layer beneath the alloy. From comparisons with theoretical calculations, we argue that, unlike an ordinary enhancement-mode SiGe p-channel metal–oxide–semiconductor structure, this configuration leads to a decrease of interface roughness scattering with increasing sheet carrier density. We also speculate on the nature of the interface charge observed in these structures at low temperature
Particle production from nonlocal gravitational effective action
In this paper we show how the nonlocal effective action for gravity, obtained
after integrating out the matter fields, can be used to compute particle
production and spectra for different space-time metrics. Applying this
technique to several examples, we find that the perturbative calculation of the
effective action up to second order in curvatures yields exactly the same
results for the total number of particles as the Bogolyubov transformations
method, in the case of masless scalar fields propagating in a Robertson-Walker
space-time. Using an adiabatic approximation we also obtain the corresponding
spectra and compare the results with the traditional WKB approximation.Comment: 22 pages, LaTeX, no figures. Corrected version with new comments and
results. To appear in Phys. Rev.
Extremely high room-temperature two-dimensional hole gas mobility in Ge/Si0.33Ge0.67/Si(001) p-type modulation-doped heterostructures
To extract the room-temperature drift mobility and sheet carrier density of two-dimensional hole gas (2DHG) that form in Ge strained channels of various thicknesses in Ge/Si0.33Ge0.67/Si(001) p-type modulation-doped heterostructures, the magnetic field dependences of the magnetoresistance and Hall resistance at temperature of 295 K were measured and the technique of maximum entropy mobility spectrum analysis was applied. This technique allows a unique determination of mobility and sheet carrier density of each group of carriers present in parallel conducting multilayers semiconductor heterostructures. Extremely high room-temperature drift mobility (at sheet carrier density) of 2DHG 2940 cm2 V–1 s–1 (5.11×1011 cm–2) was obtained in a sample with a 20 nm thick Ge strained channel
Advances in targeted Alpha therapy for prostate cancer
BACKGROUND: Amongst therapeutic radiopharmaceuticals, targeted alpha therapy (TαT) can deliver potent and local radiation selectively to cancer cells as well as the tumor microenvironment and thereby control cancer while minimizing toxicity. DESIGN: In this review, we discuss the history, progress, and future potential of TαT in the treatment of prostate cancer, including dosimetry-individualized treatment planning, combinations with small-molecule therapies, and conjugation to molecules directed against antigens expressed by prostate cancer cells, such as prostate-specific membrane antigen (PSMA) or components of the tumor microenvironment. RESULTS: A clinical proof of concept that TαT is efficacious in treating bone-metastatic castration-resistant prostate cancer has been demonstrated by radium-223 via improved overall survival and long-term safety/tolerability in the phase III ALSYMPCA trial. Dosimetry calculation and pharmacokinetic measurements of TαT provide the potential for optimization and individualized treatment planning for a precision medicine-based cancer management paradigm. The ability to combine TαTs with other agents, including chemotherapy, androgen receptor (AR)-targeting agents, DNA repair inhibitors, and immuno-oncology agents, is under investigation. Currently, TαTs that specifically target prostate cancer cells expressing PSMA represents a promising therapeutic approach. Both PSMA-targeted actinium-225 and thorium-227 conjugates are under investigation. CONCLUSIONS: The described clinical benefit, safety and tolerability of radium-223 and the recent progress in TαT trial development suggest that TαT occupies an important new role in prostate cancer treatment. Ongoing studies with newer dosimetry methods, PSMA targeting, and novel approaches to combination therapies should expand the utility of TαT in prostate cancer treatment
Extinction in Lotka-Volterra model
Competitive birth-death processes often exhibit an oscillatory behavior. We
investigate a particular case where the oscillation cycles are marginally
stable on the mean-field level. An iconic example of such a system is the
Lotka-Volterra model of predator-prey competition. Fluctuation effects due to
discreteness of the populations destroy the mean-field stability and eventually
drive the system toward extinction of one or both species. We show that the
corresponding extinction time scales as a certain power-law of the population
sizes. This behavior should be contrasted with the extinction of models stable
in the mean-field approximation. In the latter case the extinction time scales
exponentially with size.Comment: 11 pages, 17 figure
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