442 research outputs found
Molecular Dynamics Simulations of Lead and Lithium in Liquid Phase
Pb17Li is today a reference breeder material in diverse fusion R&D programs worldwide. Extracting dynamic and structural properties of liquid LiPb mixtures via molecular dynamics simulations, represent a crucial step for multiscale modeling efforts in order to understand the suitability of this compound for future Nuclear Fusion technologies. At present a Li-Pb cross potential is not available in the literature. Here we present our first results on the validation of two semi-empirical potentials for Li and Pb in liquid phase. Our results represent the establishment of a solid base as a previous but crucial step to implement a LiPb cross potential. Structural and thermodynamical analyses confirm that the implemented potentials for Li and Pb are realistic to simulate both elements in the liquid phase
The effects of over-indebtedness on individual health
This paper uses data from the 2002-2005-2008 waves of the Spanish Survey of
Household Finances (EFF) to investigate whether debts burdens hamper people's
health. Several measures of debt strain are constructed, including debt-to-income
ratios, the existence of debt arrears and amounts of outstanding debts. The paper
also differentiates between mortgage and non-mortgage debts and explores the role
of social norm effects in the debt-health relationship. The results, based on a
random effects model extended to include a Mundlak term, show that nonmortgage
debt payments and debt arrears affect significantly people's health.
Furthermore, mild social norm effects are detected, according to which being less
indebted than the reference group results, ceteris paribus, in better health
Machine Learning for Screening Large Organic Molecules
Organic semiconductors are promising materials for cheap, scalable and
sustainable electronics, light-emitting diodes and photovoltaics. For organic
photovoltaic cells, it is a challenge to find compounds with suitable
properties in the vast chemical compound space. For example, the ionization
energy should fit to the optical spectrum of sun light, and the energy levels
must allow efficient charge transport. Here, a machine-learning model is
developed for rapidly and accurately estimating the HOMO and LUMO energies of a
given molecular structure. It is build upon the SchNet model (Sch\"utt et al.
(2018)) and augmented with a `Set2Set' readout module (Vinyals et al. (2016)).
The Set2Set module has more expressive power than sum and average aggregation
and is more suitable for the complex quantities under consideration. Most
previous models have been trained and evaluated on rather small molecules.
Therefore, the second contribution is extending the scope of machine-learning
methods by adding also larger molecules from other sources and establishing a
consistent train/validation/test split. As a third contribution, we make a
multitask ansatz to resolve the problem of different sources coming at
different levels of theory. All three contributions in conjunction bring the
accuracy of the model close to chemical accuracy.Comment: Presented at E-MRS Fall Meeting 2022, Symposium
Does income deprivation affect people's mental well-being?
Incluye bibliografĂaEste trabajo utiliza datos de panel de olas 2002-2010 del Panel SocioeconĂłmico Alemán, a fin de evaluar el impacto que la privaciĂłn en tĂ©rminos de renta familiar tiene sobre el bienestar mental. La heterogeneidad no observable está controlada a travĂ©s de un modelo de efectos aleatorios que incluye un tĂ©rmino de Mundlak y controles explĂcitos para la personalidad de los individuos. El artĂculo muestra que, dada una renta familiar, una posiciĂłn menos favorable en la posiciĂłn relativa de la distribuciĂłn de renta se traduce en un menor bienestar mental. Este efecto no es estadĂsticamente significativo entre las mujeres. Sin embargo, en el caso de los hombres el efecto perjudicial que un aumento de una desviaciĂłn estándar en la privaciĂłn de renta tiene sobre el bienestar mental equivale a un pĂ©rdida del 30% en la renta familiar permanente. Curiosamente, este impacto difiere entre individuos dotados con diferentes habilidades no cognitivas. Estos resultados sugieren que las polĂticas, prácticas e iniciativas orientadas a mejorar el bienestar de los ciudadanos europeos requieren una mayor consideraciĂłn de la renta relativa de los individuosThis paper uses panel data from the 2002-2010 waves of the German Socio-Economic Panel dataset (SOEP) to assess the impact of income deprivation upon individual mental well-being. Unobserved heterogeneity is controlled for by means of a random effects model extended to include a Mundlak term and explicit controls for the respondents’ personality traits. The paper shows that, for a given household income, a less favourable relative position in the income distribution is associated with lower mental well-being. This effect is not statistically significant among women, though. Among men, a one standard deviation increase in income deprivation is found to be as harmful as a reduction in permanent household income of almost 30%. Interestingly, this impact is found to differ among individuals endowed with different sets of non-cognitive skills. We suggest that policies, practices and initiatives aimed at improving well-being among European citizens require a better understanding of individuals’ sensitiveness to others’ incom
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