1,776 research outputs found

    Young-adult children of alcoholic parents: protective effects of positive family functioning

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    The occurrence of alcoholism is clustered within families, but the detrimental effect of a positive family history may vary with the degree of family impairment involved. In this study we assessed the effects of family history and family environment on alcohol misuse. From ongoing studies we recruited parents who had a child aged 18–30, 20 with a DSM-III-R alcohol dependence diagnosis, 20 without. The child then completed a multidimensional assessment. The young-adult participants included 20 men and 20 women (mean age=24.8). Differences by family history were restricted to substance abuse behaviors. While a high level of alcohol problems occurred in both groups, those with an alcohol-dependent parent were more likely to be heavy drinkers and showed more symptoms of alcohol dependence. Overall psychological adjustment did not differ between the groups, however. Alcohol misuse measures did correlate moderately with symptoms of poor emotional health. The most important correlates of alcohol misuse measures in this study were exposure to parental alcoholism, abusive punishment, and psychological symptoms, with some separation of effects in the two subgroups. Psychological symptoms had a stronger relationship with misuse in subjects with social-drinking parents, while abuse was more associated in the group with an alcohol-dependent parent. These results confirm the importance of environmental interactions with familial risk. A biological vulnerability from an alcohol-dependent parent was not sufficient or necessary for the participants in this study to develop alcohol dependence as a young adult, although there was an increased risk. There appear to be strong protective effects of positive family relationships on the potential negative effects of a family history of alcoholism.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73415/1/j.1360-0443.1992.tb02681.x.pd

    Nonthermal Emission from the Arches Cluster (G0.121+0.017) and the Origin of γ\gamma-ray Emission from 3EG J1746-2851

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    High resolution VLA observations of the Arches cluster near the Galactic center show evidence of continuum emission at λ\lambda3.6, 6, 20 and 90cm. The continuum emission at λ\lambda90cm is particularly striking because thermal sources generally become optically thick at longer wavelengths and fall off in brightness whereas non-thermal sources increase in brightness. It is argued that the radio emission from this unique source has compact and diffuse components produced by thermal and nonthermal processes, respectively. Compact sources within the cluster arise from stellar winds of mass-losing stars (Lang, Goss & Rodriguez 2001a) whereas diffuse emission is likely to be due to colliding wind shocks of the cluster flow generating relativistic particles due to diffuse shock acceleration. We also discuss the possibility that γ\gamma-ray emission from 3EG J1746--2851, located within 3.3' of the Arches cluster, results from the inverse Compton scattering of the radiation field of the cluster.Comment: 15 pages, four figures, ApJL (in press

    Evidence for a Weak Galactic Center Magnetic Field from Diffuse Low Frequency Nonthermal Radio Emission

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    New low-frequency 74 and 330 MHz observations of the Galactic center (GC) region reveal the presence of a large-scale (6\arcdeg\times 2\arcdeg) diffuse source of nonthermal synchrotron emission. A minimum energy analysis of this emission yields a total energy of (ϕ4/7f3/7)×1052\sim (\phi^{4/7}f^{3/7})\times 10^{52} ergs and a magnetic field strength of 6(ϕ/f)2/7\sim 6(\phi/f)^{2/7} \muG (where ϕ\phi is the proton to electron energy ratio and ff is the filling factor of the synchrotron emitting gas). The equipartition particle energy density is 1.2(ϕ/f)2/71.2(\phi/f)^{2/7} \evcm, a value consistent with cosmic-ray data. However, the derived magnetic field is several orders of magnitude below the 1 mG field commonly invoked for the GC. With this field the source can be maintained with the SN rate inferred from the GC star formation. Furthermore, a strong magnetic field implies an abnormally low GC cosmic-ray energy density. We conclude that the mean magnetic field in the GC region must be weak, of order 10 \muG (at least on size scales \ga 125\arcsec).Comment: 12 pages, 1 JPEG figure, uses aastex.sty; Accepted for publication, ApJL (2005, published

    The magnetic environment in the central region of nearby galaxies

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    The central regions of galaxies harbor some of the most extreme physical phenomena, including dense stellar clusters, non-circular motions of molecular clouds and strong and pervasive magnetic field structures. In particular, radio observations have shown that the central few hundred parsecs of our Galaxy has a striking magnetic field configuration. It is not yet clear whether these magnetic structures are unique to our Milky Way or a common feature of all similar galaxies. Therefore, we report on (a) a new radio polarimetric survey of the central 200 pc of the Galaxy to better characterize the magnetic field structure and (b) a search for large-scale and organized magnetized structure in the nuclear regions of nearby galaxies using data from the Very Large Array (VLA) archive. The high angular resolution of the VLA allows us to study the central 1 kpc of the nearest galaxies to search for magnetized nuclear features similar to what is detected in our own Galactic center. Such magnetic features play a important role in the nuclear regions of galaxies in terms of gas transport and the physical conditions of the interstellar medium in this unusual region of galaxies.Comment: 8 pages; Proceedings for "The Universe under the Microscope" (AHAR 2008), held in Bad Honnef (Germany) in April 2008, to be published in Journal of Physics: Conference Series by Institute of Physics Publishing, R. Schoedel, A. Eckart, S. Pfalzner, and E. Ros (eds.

    Impact of Systematics on SZ-Optical Scaling Relations

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    One of the central goals of multi-wavelength galaxy cluster cosmology is to unite all cluster observables to form a consistent understanding of cluster mass. Here, we study the impact of systematic effects from optical cluster catalogs on stacked SZ signals. We show that the optically predicted Y-decrement can vary by as much as 50% based on the current 2 sigma systematic uncertainties in the observed mass-richness relationship. Mis-centering and impurities will suppress the SZ signal compared to expectations for a clean and perfectly centered optical sample, but to a lesser degree. We show that the level of these variations and suppression is dependent on the amount of systematics in the optical cluster catalogs. We also study X-ray luminosity-dependent sub-sampling of the optical catalog and find that it creates Malmquist bias increasing the observed Y-decrement of the stacked signal. We show that the current Planck measurements of the Y-decrement around SDSS optical clusters and their X-ray counterparts are consistent with expectations after accounting for the 1 sigma optical systematic uncertainties using the Johnston mass richness relation.Comment: 6 pages, 4 figures. Revised to match version accepted in the Astrophysical Journa

    Electromechanics of charge shuttling in dissipative nanostructures

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    We investigate the current-voltage (IV) characteristics of a model single-electron transistor where mechanical motion, subject to strong dissipation, of a small metallic grain is possible. The system is studied both by using Monte Carlo simulations and by using an analytical approach. We show that electromechanical coupling results in a highly nonlinear IV-curve. For voltages above the Coulomb blockade threshold, two distinct regimes of charge transfer occur: At low voltages the system behave as a static asymmetric double junction and tunneling is the dominating charge transfer mechanism. At higher voltages an abrupt transition to a new shuttle regime appears, where the grain performs an oscillatory motion back and forth between the leads. In this regime the current is mainly mediated by charges that are carried on the grain as it moves from one lead to the other.Comment: 8 pages, 10 figures, final version to be published in PR

    Exploring what lies behind public preferences for avoiding health losses caused by lapses in healthcare safety and patient lifestyle choices

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    © 2013 Singh et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.This article has been made available through the Brunel Open Access Publishing Fund.Background: Although many studies have identified public preferences for prioritising health care interventions based on characteristics of recipient or care, very few of them have examined the reasons for the stated preferences. We conducted an on-line person trade-off (PTO) study (N=1030) to investigate whether the public attach a premium to the avoidance of ill health associated with alternative types of responsibilities: lapses in healthcare safety, those caused by individual action or lifestyle choice; or genetic conditions. We found that the public gave higher priority to prevention of harm in a hospital setting such as preventing hospital associated infections than genetic disorder but drug administration errors were valued similar to genetic disorders. Prevention of staff injuries, lifestyle diseases and sports injuries, were given lower priority. In this paper we aim to understand the reasoning behind the responses by analysing comments provided by respondents to the PTO questions. Method: A majority of the respondents who participated in the survey provided brief comments explaining preferences in free text responses following PTO questions. This qualitative data was transformed into explicit codes conveying similar meanings. An overall coding framework was developed and a reliability test was carried out. Recurrent patterns were identified in each preference group. Comments which challenged the assumptions of hypothetical scenarios were also investigated. Results: NHS causation of illness and a duty of care were the most cited reasons to prioritise lapses in healthcare safety. Personal responsibility dominated responses for lifestyle related contexts, and many respondents mentioned that health loss was the result of the individual’s choice to engage in risky behaviour. A small proportion of responses questioned the assumptions underlying the PTO questions. However excluding these from the main analysis did not affect the conclusions. Conclusion: Although some responses indicated misunderstanding or rejection of assumptions we put forward, the results were still robust. The reasons put forward for responses differed between comparisons but responsibility was the most frequently cited. Most preference elicitation studies only focus on eliciting numerical valuations but allowing for qualitative data can augment understanding of preferences as well as verifying results.EPSRC through the MATCH programme(EP/F063822/1 and EP/G012393/1) and HERG within Brunel University

    Low frequency current noise of the single-electron shuttle

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    Coupling between electronic and mechanical degrees of freedom in a single electron shuttle system can cause a mechanical instability leading to shuttle transport of electrons between external leads. We predict that the resulting low frequency current noise can be enhanced due to amplitude fluctuations of the shuttle oscillations. Moreover, at the onset of mechanical instability a pronounced peak in the low frequency noise is expected.Comment: 14 pages, 3 figures, 1 tabl
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