858 research outputs found

    Climate change impact on the leaching of a heavy metal contamination in a small lowland catchment

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    The objective of this study was to assess the potential effects of climate change on the transport of pre-existing spatially-extensive trace metal contamination to a small lowland catchment in the south of the Netherlands. The area surrounding the Keersop has been contaminated with heavy metals by the atmospheric emissions of four zinc ore smelters. This heavy metal contamination, e.g. with Cd and Zn, has accumulated in the topsoil and leaches towards surface water system, especially during high groundwater levels and high discharge rates. Simulated projections of future climate predict increased precipitation in winter, less precipitation in summer, and higher air temperatures throughout the year. These climate change scenarios projected lower groundwater levels and lower discharge rates. As a result of lower groundwater levels, transport of Cd and Zn towards surface water is also projected to decrease in the future climate. These results indicate a positive effect of climate change on a limited aspect of surface water quality

    Multilevel analysis of nuclear dynamics in lamin perturbed fibroblasts

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    The nuclear lamina provides structural support to the nucleus and has a central role in defining nuclear organization. Defects in its filamentous constituents, the lamins, lead to a class of diseases collectively referred to as laminopathies. On the cellular level, lamin mutations affect the physical integrity of nuclei and nucleo-cytoskeletal interactions, resulting in increased susceptibility to mechanical stress and altered gene expression [1]. Most studies regarding the mechanical properties of the nucleus in laminopathic conditions are based on the induction of extracellular stress, such as strain or compression, and focus on nuclear integrity and/or nucleo-cytoskeletal interaction [2]. Far less is known about the role of nuclear organization and mobility under basal steady-state conditions. In this study, we quantitatively compared nuclear organization, nuclear deformation and chromatin mobility of fibroblasts from a Hutchinson-Gilford progeria patient with cells from a lamin A/C-deficient patient and wild-type dermal fibroblasts. To this end, we created a toolbox in imageJ for automatically analyzing both nuclear as well as subnuclear dynamics in living cells. Simultaneously, we developed a workflow for comparing cellular morphology and subcellular protein distribution in a high content fashion. We found that the absence of functional lamin A/C leads to increased nuclear plasticity on the hour and minute time scale but also to increased intranuclear mobility down to the seconds time scale. In contrast, progeria cells showed overall reduced nuclear dynamics. In addition, high content analysis revealed marked morphological and topological differences between different culture passages within a cell type and between different pathological variants of culture-age matched laminopathic cell types

    A Schema Therapy Based Milieu in Secure Residential Youth Care:Effects on Aggression, Group Climate, Repressive Staff Interventions, and Team Functioning

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    Group care workers of residential youth care settings face the challenge of creating a warm and involved treatment climate against the demands and restrictions of the treatment setting. We tested the effects of SafePath, a milieu-based intervention based on Schema Therapy principles, during the first year of implementation on two secure residential treatment units compared to two control units. Staff’s daily reports on 139 individual patients were coded on use of schema mode language (implementation check), occurrences of aggression (primary outcome) and repressive staff interventions. In addition, repeated questionnaires were filled out by patients (n = 87) on group climate and by staff (n = 50) on team functioning. Compared to the control units, SafePath units showed higher improvements in group climate and repressive interventions. Both SafePath and control units showed decreased aggression over time. Team functioning was consistently better in the SafePath units compared to the care-as-usual units from baseline through 12 months. In conclusion, a Schema Therapy based milieu as implemented with SafePath may contribute to a warm and supportive group climate with less repressive interventions in secure residential youth care

    Substance Misuse Education for Physicians: Why Older People are Important.

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    This perspective article focuses on the need for training and education for undergraduate medical students on substance-related disorders, and describes initiatives undertaken in the United Kingdom (UK), Netherlands, United States (US), and Norway to develop the skills, knowledge, and attitudes needed by future doctors to treat patients adequately. In addition, we stress that in postgraduate training, further steps should be taken to develop Addiction Medicine as a specialized and transverse medical domain. Alcohol use disorder is a growing public health problem in the geriatric population, and one that is likely to continue to increase as the baby boomer generation ages. Prescription drug misuse is a major concern, and nicotine misuse remains problematic in a substantial minority. Thus, Addiction Medicine training should address the problems for this specific population. In recent years, several countries have started an Addiction Medicine specialty. Although addiction psychiatry has been a subspecialty in the UK and US for more than 20 years, in most countries it has been a more recent development. Additional courses on addiction should be integrated into the curriculum at both undergraduate and postgraduate levels, as well as form part of the continuous training of other medical specialists. It is recommended that further research and mapping of what is currently taught in medical programs be undertaken, so as to enhance medical education in addiction and improve treatment services

    Observation of coherent transients in ultrashort chirped excitation of an undamped two-level system

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    The effects of Coherent excitation of a two level system with a linearly chirped pulse are studied theoretically and experimentally (in Rb (5s - 5p)) in the low field regime. The Coherent Transients are measured directly on the excited state population on an ultrashort time scale. A sharp step corresponds to the passage through resonance. It is followed by oscillations resulting from interferences between off-resonant and resonant contributions. We finally show the equivalence between this experiment and Fresnel diffraction by a sharp edge.Comment: 4 pages, 4 figures, to appear in PR

    Floquet dynamics in light-driven solids

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    We demonstrate how the properties of light-induced electronic Floquet states in solids impact natural physical observables, such as transport properties, by capturing the environmental influence on the electrons. We include the environment as dissipative processes, such as inter-band decay and dephasing, often ignored in Floquet predictions. These dissipative processes determine the Floquet band occupations of the emergent steady state, by balancing out the optical driving force. In order to benchmark and illustrate our framework for Floquet physics in a realistic solid, we consider the light-induced Hall conductivity in graphene recently reported by J.~W.~McIver, et al., Nature Physics (2020). We show that the Hall conductivity is estimated by the Berry flux of the occupied states of the light-induced Floquet bands, in addition to the kinetic contribution given by the average band velocity. Hence, Floquet theory provides an interpretation of this Hall conductivity as a geometric-dissipative effect. We demonstrate this mechanism within a master equation formalism, and obtain good quantitative agreement with the experimentally measured Hall conductivity, underscoring the validity of this approach which establishes a broadly applicable framework for the understanding of ultrafast non-equilibrium dynamics in solids
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