7,170 research outputs found
Heat fluxes between the Guadalquivir river and the Gulf of Cádiz Continental Shelf
An 18-year time series of daily sea surface temperature of Gulf of Cadiz and an 18-month time series of temperature collected in the vicinity of the Guadalquivir estuary mouth have been analyzed to investigate the heat exchange between the estuary and the adjacent continental shelf. The first time identifies a continental shelf area where seasonal thermal oscillation signal (amplitudes and phase) changes abruptly.
In order to explain this anomaly, the second data set allows a description of thermal fluctuations in a wide range of frequencies and an estimation of the upstream heat budget of the Guadalquivir estuary. Results show that high frequency thermal signal, diurnal and semidiurnal, and water flux signal through Guadalquivir mouth, mainly semidiurnal, apparently interact randomly to give a small exchange of thermal energy at high frequency. There is no trace, at the estuary's mouth, of daily heat exchanges with intertidal mudflats probably because it tends to cancel on daily time scales. Results also show that fluctuations of estimated air-sea fluxes force fluctuations of temperature in a quite homogeneous estuarine, with a delay of 20 days. The along-channel thermal energy gradient reaches magnitudes of 300-400 J m-4 near the mouth during the summer and winter and drives the estuary-shelf exchange of thermal energy at seasonal scale. Particularly, the thermal heat imported by the estuary from the shelf area during late fall-winter-early spring of 2008/2009 is balanced by the thermal heat that the estuary exports to the shelf area during late spring-summer of 2008. In summary, Guadalquivir river removes/imports excess of thermal energy towards/from the continental shelf seasonally, as a mechanism to accommodate excess of heat from one side respect to the other side.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech. Autoridad Portuaria de Sevilla (APS
3D hydrodynamic model as a tool for more efficient port management and operations.
Ports have been attempting to increase their competitiveness by enhancing their productivity and operate in a more environmentally friendly way. The Port of Seville is located in the Guadalquivir River in the south of Spain and it is the unique Spanish inland port. The estuary has generated and is still generating conflicts of interests. The access channel to the port is being periodically dredged, the natural course has been anthropologically modified several times, original salt marshes have been transformed to grow rice and approximately one-fourth of the total surface of the estuary is now part of two protected areas, one of them is a UNESCO_MAB Biosphere Reserve. Despite its socio-economic and environmental significance there is a surprising lack of scientific and technical information about the environmental interactions between the port activities and the Guadalquivir estuary stakeholders.
A 3D hydrodynamic model has been developed to study the tidal regime, water circulation, temperature and salinity distributions, flooding areas and the sediment dynamics in the estuary. The model output has been validated with in situ current speed, direction, water elevation and also with temperature and salinity measurements. Good agreement between modeled and real measurements have been obtained. Our preliminary results show that the vessel traffic management could be improved by using the tidal elevations and currents calculated by the model in the whole estuary. The interactions among the port activities (mainly due of changes in the sediments dynamics), the watershed management and the saline intrusion evolution will be studied in detail.
3D Hydrodynamic Modelling provide spatially explicit information on the key variables governing the dynamics of estuarine areas. The numerical model is a powerful tool to effectively guide the management and operations of ports located in a complex socio-ecological systems.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech
The LMO2 -25 Region Harbours GATA2-Dependent Myeloid Enhancer and RUNX-Dependent T-Lymphoid Repressor Activity.
Lim domain only 2 (LMO2) is a transcriptional co-factor required for angiogenesis and the specification of haematopoietic cells during development. LMO2 is widely expressed within haematopoiesis with the exception of T-cells. Failure to downregulate LMO2 during T-cell maturation leads to leukaemia, thus underlining the critical nature of context-dependent regulation of LMO2 expression. We previously identified a distal regulatory element of LMO2 (element -25) that cooperates with the proximal promoter in directing haematopoietic expression. Here we dissected the functional activity of element -25 and showed it to consist of two modules that conferred independent and cell-type specific activities: a 3' myeloid enhancer and a 5' T-cell repressor. The myeloid enhancer was bound by GATA2 in progenitors and its activity depended on a highly conserved GATA motif, whereas the T-cell repressor moiety of element -25 was bound by the Core Binding Factor in T-cells and its repressive activity depended on a highly conserved RUNT motif. Since the myeloid enhancer and nearby downstream region is recurrently involved in oncogenic translocations, our data suggest that the -25 enhancer region provides an open chromatin environment prone to translocations, which in turn cause aberrant LMO2 expression in T-cells due to the removal of the adjacent T-cell repressor.This work was supported by Leukaemia and Lymphoma Research (BG) (http://leukaemialymphomaresearch.org.uk/, grants number 07060 and 12029), a fellowship from the Swiss National Science Foundation (NB) (http://www.snf.ch/) and Wellcome Trust Infrastructure support funding for the Cambridge Institute for Medical
Research ((http://www.wellcome.ac.uk/) grant number 100140/Z/12/Z) and the Wellcome Trust and MRC Cambridge Stem Cell Institute (http://www.mrc.ac.uk/, grant
number 097922/Z/11/Z).This is the final version of the article. It first appeared from PLOS via http://dx.doi.org/10.1371/journal.pone.013157
Understanding Nanopore Window Distortions in the Reversible Molecular Valve Zeolite RHO
Molecular valves are becoming popular for potential biomedical applications.
However, little is known concerning their performance in energy and
environmental areas. Zeolite RHO shows unique pore deformations upon changes in
hydration, cation siting, cation type, or temperature-pressure conditions. By
varying the level of distortion of double eight-rings, it is possible to
control the adsorption properties, which confer a molecular valve behavior to
this material. We have employed interatomic potentials-based simulations to
obtain a detailed atomistic view of the structural distortion mechanisms of
zeolite RHO, in contrast with the averaged and space group restricted
information provided by diffraction studies. We have modeled four
aluminosilicate structures, containing Li, Na, K, Ca, and
Sr cations. The distortions of the three different zeolite rings are
coupled, and the six- and eight-membered rings are largely flexible. A large
dependence on the polarizing power of the extra-framework cations and with the
loading of water has been found for the minimum aperture of the eight-membered
rings that control the nanovalve effect. The calculated energy barriers for
moving the cations across the eight-membered rings are very high, which
explains the experimentally observed slow kinetics of the phase transition as
well as the appearance of metastable phases
Principales cambios en la epidemiologĂa de las enfermedades infecciosas en el mundo
ResumenEste trabajo revisa el concepto y el impacto de las nuevas enfermedades infecciosas y las razones para su emergencia; a partir de ahĂ, describe algunas estrategias para su control. Entre estas medidas se encuentra, en primer lugar. el fortalecimiento de los servicios de salud pĂşblica, como la vigilancia epidemiolĂłgica y los laboratorios de salud pĂşblica, que permitan identificar nuevos brotes y nuevas enfermedades infecciosas. En segundo lugar la difusiĂłn rápida de los conocimientos generados, hasta las personas encargadas del control de enfermedades. En tercer lugar, la promociĂłn de la investigaciĂłn en este campo y la formaciĂłn de personal especializado. Dentro de la investigaciĂłn es prioritario el desarrollo de nuevas vacunas, potencialmente Ăştiles tambiĂ©n para el control de las enfermedades crĂłnicas, consideradas hasta ahora como no infecciosas (Ăşlceras pĂ©ptica, coronariopatĂas, etcĂ©tera). Por Ăşltimo, se recomienda un “nuevo abordaje epidemiolĂłgico”, que integre los aspectos mĂ©dicos y sociales de las enfermedades. Este abordaje es además el que permite la necesaria colaboraciĂłn con los profesionales de otros campos, como la inmunologĂa, la microbiologĂa, la clĂnica y las ciencias sociales.SummaryThis paper reviews the concept and impact of new infectious diseases and the reasons for their emergence; taking that as a start, it describes some strategies to control them. Among these measures we can find, firstly, the strengthening of public health services, such as epidemiological surveillance and public health laboratories, which allow us to identify new outbreaks and new infectious diseases. Secondly, the quick spread of the knowledge that is generated towards the people who are in charge of the control of diseases, and thirdly, the promotion of research in this field and the training of specialized staff. In the field of research, priority is given to the development of new vaccinations that are potentially useful for the control of chronic diseases which were considered until now as non-infectious (peptic ulcer, coronarypathies, etc.). Finally, a new epidemiological approach which integrates medical and social aspects of diseases is advised. Besides, this approach is what allows the necessary collaboration with professionals from other fields, such as immunology, microbiology, clinics and social sciences
Dealing with the nucleus during cell migration
© 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).The position of the nucleus within cells is a key event during cell migration. The movement and positioning of the nucleus strongly impacts cell migration. Notably, the last two years largely contributed to emphasise the dynamicity of the nucleus-cytoskeleton interactions that occur during cell migration. Nuclei are under continuous tension from opposing intracellular forces and its tether to the cytoskeleton can be regulated at different levels. Interestingly, it was showed how nuclear positioning is highly related to cell function. In most migrating cells, including cancer cells, the nucleus can be the rate limiting step of cell migration and is placed away from the leading edge. By contrast, leukocytes position their nucleus close to the lamellipodia at the leading edge, and the nucleus contributes to drilling through the endothelium. Differences in cell migration in 2D versus 3D environments are also evident. The mechanisms and forces at play during nuclear positioning and translocation are clearly affected by the nature of the substrate. As such nuclear positioning during cell migration can vary between cell types and environments. In this review we aim to give an overview of the latest discoveries in the field revealing how nuclear positioning is tightly regulated, not only by intrinsic nuclear properties, such as deformability, nuclear envelope content or nucleus-cytoskeleton connectivity, but also by the microenvironment.This work was supported by the European Research Council, EMBO installation, LISBOA-01-0145-FEDER-007391, project cofunded by FEDER, through POR Lisboa 2020 — Programa Operacional Regional de Lisboa, Portugal 2020 and Fundação para a Ciência e a Tecnologia.info:eu-repo/semantics/publishedVersio
HIV Infection and the Central Nervous System: A Primer
The purpose of this brief review is to prepare readers who may be unfamiliar with Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome (HIV/AIDS) and the rapidly accumulating changes in the epidemic by providing an introduction to HIV disease and its treatment. The general concepts presented here will facilitate understanding of the papers in this issue on HIV-associated neurocognitive disorders (HAND). Toward that end, we briefly review the biology of HIV and how it causes disease in its human host, its epidemiology, and how antiretroviral treatments are targeted to interfere with the molecular biology that allows the virus to reproduce. Finally, we describe what is known about how HIV injures the nervous system, leading to HAND, and discuss potential strategies for preventing or treating the effects of HIV on the nervous system
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