3,158 research outputs found

    Mental Illness and Mental Health: The Two Continua Model Across the Lifespan

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    Mental health has long been defined as the absence of psychopathologies, such as depression and anxiety. The absence of mental illness, however, is a minimal outcome from a psychological perspective on lifespan development. This article therefore focuses on mental illness as well as on three core components of positive mental health: feelings of happiness and satisfaction with life (emotional well-being), positive individual functioning in terms of self-realization (psychological well-being), and positive societal functioning in terms of being of social value (social well-being). The two continua model holds that mental illness and mental health are related but distinct dimensions. This model was studied on the basis of a cross-sectional representative internet survey of Dutch adults (N = 1,340; 18–87 years). Mental illness was measured with the Brief Symptom Inventory and mental health with the Mental Health Continuum Short Form. It was found that older adults, except for the oldest-old, scored lower on psychopathological symptoms and were less likely to be mentally ill than younger adults. Although there were fewer age differences for mental health, older adults experienced more emotional, similar social and slightly lower psychological well-being. In sum, today’s older adults have fewer mental illness problems, but they are not in a better positive mental health than today’s younger adults. These findings support the validity of the two continua model in adult development

    The Potential Energy Landscape and Mechanisms of Diffusion in Liquids

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    The mechanism of diffusion in supercooled liquids is investigated from the potential energy landscape point of view, with emphasis on the crossover from high- to low-T dynamics. Molecular dynamics simulations with a time dependent mapping to the associated local mininum or inherent structure (IS) are performed on unit-density Lennard-Jones (LJ). New dynamical quantities introduced include r2_{is}(t), the mean-square displacement (MSD) within a basin of attraction of an IS, R2(t), the MSD of the IS itself, and g_{loc}(t) the mean waiting time in a cooperative region. At intermediate T, r2_{is}(t) posesses an interval of linear t-dependence allowing calculation of an intrabasin diffusion constant D_{is}. Near T_{c} diffusion is intrabasin dominated with D = D_{is}. Below T_{c} the local waiting time tau_{loc} exceeds the time, tau_{pl}, needed for the system to explore the basin, indicating the action of barriers. The distinction between motion among the IS below T_{c} and saddle, or border dynamics above T_{c} is discussed.Comment: submitted to pr

    Inherent-Structure Dynamics and Diffusion in Liquids

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    The self-diffusion constant D is expressed in terms of transitions among the local minima of the potential (inherent structure, IS) and their correlations. The formulae are evaluated and tested against simulation in the supercooled, unit-density Lennard-Jones liquid. The approximation of uncorrelated IS-transition (IST) vectors, D_{0}, greatly exceeds D in the upper temperature range, but merges with simulation at reduced T ~ 0.50. Since uncorrelated IST are associated with a hopping mechanism, the condition D ~ D_{0} provides a new way to identify the crossover to hopping. The results suggest that theories of diffusion in deeply supercooled liquids may be based on weakly correlated IST.Comment: submitted to PR

    Instantaneous Normal Mode analysis of liquid HF

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    We present an Instantaneous Normal Modes analysis of liquid HF aimed to clarify the origin of peculiar dynamical properties which are supposed to stem from the arrangement of molecules in linear hydrogen-bonded network. The present study shows that this approach is an unique tool for the understanding of the spectral features revealed in the analysis of both single molecule and collective quantities. For the system under investigation we demonstrate the relevance of hydrogen-bonding ``stretching'' and fast librational motion in the interpretation of these features.Comment: REVTeX, 7 pages, 5 eps figures included. Minor changes in the text and in a figure. Accepted for publication in Phys. Rev. Let

    Configurational entropy of hard spheres

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    We numerically calculate the configurational entropy S_conf of a binary mixture of hard spheres, by using a perturbed Hamiltonian method trapping the system inside a given state, which requires less assumptions than the previous methods [R.J. Speedy, Mol. Phys. 95, 169 (1998)]. We find that S_conf is a decreasing function of packing fraction f and extrapolates to zero at the Kauzmann packing fraction f_K = 0.62, suggesting the possibility of an ideal glass-transition for hard spheres system. Finally, the Adam-Gibbs relation is found to hold.Comment: 10 pages, 6 figure

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    Burden of Mental Disorders and Suicide Attributable to Childhood Maltreatment

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    Importance: The proportion of mental disorders and burden causally attributable to childhood maltreatment is unknown. Objective: To determine the contribution of child maltreatment to mental health conditions in Australia, accounting for genetic and environmental confounding. Design, Setting, and Participants: This meta-analysis involved an epidemiological assessment accounting for genetic and environmental confounding between maltreatment and mental health and 3 cross-sectional national surveys: the Australian Child Maltreatment Study (ACMS) 2023, National Study of Mental Health and Well-being 2020-2022, and Australian Burden of Disease Study 2023. Causal estimates were derived on the association between childhood maltreatment and mental health conditions from a meta-analysis of quasi-experimental studies. This was combined with the prevalence of maltreatment from the ACMS to calculate the population attributable fraction (PAF). The PAF was applied to the number and burden of mental health conditions in Australia, sourced from 2 population-based, nationally representative surveys of Australians aged 16 to 85 years, to generate the number and associated burden of mental disorders attributable to child maltreatment. Exposure: Physical abuse, sexual abuse, emotional abuse, or neglect prior to age 18 years. Main Outcomes and Measures: Proportion and number of cases, years of life lost, years lived with disability, and disability-adjusted life-years of mental health conditions (anxiety, depression, harmful alcohol and drug use, self-harm, and suicide attempt) attributable to childhood maltreatment. Results: Meta-analytic estimates were generated from 34 studies and 54646 participants and applied to prevalence estimates of childhood maltreatment generated from 8503 Australians. Childhood maltreatment accounted for a substantial proportion of mental health conditions, ranging from 21% (95% CI, 13%-28%) for depression to 41% (95% CI, 27%-54%) of suicide attempts. More than 1.8 million cases of depressive, anxiety, and substance use disorders could be prevented if childhood maltreatment was eradicated. Maltreatment accounted for 66143 years of life lost (95% CI, 43313-87314), primarily through suicide, and 184636 disability-adjusted life-years (95% CI, 109321-252887). Conclusions and Relevance: This study provides the first estimates of the causal contribution of child maltreatment to mental health in Australia. Results highlight the urgency of preventing child maltreatment to reduce the population prevalence and burden of mental disorders.

    Instantaneous Normal Mode Analysis of Supercooled Water

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    We use the instantaneous normal mode approach to provide a description of the local curvature of the potential energy surface of a model for water. We focus on the region of the phase diagram in which the dynamics may be described by the mode-coupling theory. We find, surprisingly, that the diffusion constant depends mainly on the fraction of directions in configuration space connecting different local minima, supporting the conjecture that the dynamics are controlled by the geometric properties of configuration space. Furthermore, we find an unexpected relation between the number of basins accessed in equilibrium and the connectivity between them.Comment: 5 pages, 4 figure
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