469 research outputs found

    Electronic transport in gadolinium atomic-size contacts

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    We report on the fabrication, transport measurements, and density functional theory (DFT) calculations of atomic-size contacts made of gadolinium (Gd). Gd is known to have local moments mainly associated with f electrons. These coexist with itinerant s and d bands that account for its metallic character. Here we explore whether and how the local moments influence electronic transport properties at the atomic scale. Using both scanning tunneling microscope and lithographic mechanically controllable break junction techniques under cryogenic conditions, we study the conductance of Gd when only few atoms form the junction between bulk electrodes made of the very same material. Thousands of measurements show that Gd has an average lowest conductance, attributed to single-atom contact, below 2e2h. Our DFT calculations for monostrand chains anticipate that the f bands are fully spin polarized and insulating and that the conduction may be dominated by s, p, and d bands. We also analyze the electronic transport for model nanocontacts using the nonequilibrium Green's function formalism in combination with DFT. We obtain an overall good agreement with the experimental results for zero bias and show that the contribution to the electronic transport from the f channels is negligible and that from the d channels is marginal.B.O., C.S., J.F.R., J.J.P., and C.U. acknowledge financial support by MEC-Spain (Grant No. FIS2013-47328-C2 and MAT2016-78625-C2) and the Generalitat Valenciana under Grant No. PROMETEO/2012/011. C.S. and J.J.P. acknowledge the EU structural funds and the Comunidad de Madrid under NANOFRONTMAG-CM program Grant No. S2013/MIT-2850. J.L.L. and J.F.R. acknowledge Marie Curie ITN SPINOGRAPH FP7 under REA Grant Agreement No. 607904-13. B.O. acknowledges financial support by MEC Spain (Grant No. FIS2010-21883-C02-01) under brief stays abroad scholarship

    Bacterioplankton responses to riverine and atmospheric inputs in a coastal upwelling system (Ría de Vigo, NW Spain)

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    Original research paperAnthropogenic pressures are changing the magnitude and nature of matter inputs into the ocean. The Ría de Vigo (NW Spain) is a highly productive and dynamic coastal system that is likely affected by such alterations. Previous nutrient-addition microcosm experiments conducted during contrasting hydrographic conditions suggested that heterotrophic bacteria are limited by organic carbon (C) and occasionally co-limited by inorganic nutrients in this coastal area. In order to assess short-term responses in biomass, production, and respiration of heterotrophic bacteria from the Ría de Vigo to increasing amounts of natural inputs of matter, we conducted 6 microcosm experiments, wherein surface seawater collected in spring, summer, and autumn was mixed with increasing amounts of dissolved natural matter concentrates from riverine and atmospheric origin. Simultaneous experiments with controlled inorganic and/or organic additions indicated that bacteria were co-limited by inorganic nutrients and C in spring and summer and primarily limited by C in autumn. Production responded more than biomass to increasing inputs of matter, whereas respiration did not change. The bacterial production response to increasing dissolved organic C load associated with riverine and atmospheric inputs was strongly related to the relative phosphorus (P) content of the dissolved matter concentrates. Our data suggest that bacterial production might decrease with the increase of P-deficient allochthonous matter inputs, which would have important biogeochemical consequences for C cycling in coastal areas.Spanish Ministry of Science and Innovation, MINECO, CSIC, Xunta of Galicia and European Union (Marie Curie Grants)Versión del edito

    Bacterioplankton responses to riverine and atmospheric inputs in a coastal upwelling system (Ría de Vigo, NW Spain)

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    12 páginas, 5 figuras, 2 tablasAnthropogenic pressures are changing the magnitude and nature of matter inputs into the ocean. The Ría de Vigo (NW Spain) is a highly productive and dynamic coastal system that is likely affected by such alterations. Previous nutrient-addition microcosm experiments conducted during contrasting hydrographic conditions suggested that heterotrophic bacteria are limited by organic carbon (C) and occasionally co-limited by inorganic nutrients in this coastal area. In order to assess short-term responses in biomass, production, and respiration of heterotrophic bacteria from the Ría de Vigo to increasing amounts of natural inputs of matter, we conducted 6 microcosm experiments, wherein surface seawater collected in spring, summer, and autumn was mixed with increasing amounts of dissolved natural matter concentrates from riverine and atmospheric origin. Simultaneous experiments with controlled inorganic and/or organic additions indicated that bacteria were co-limited by inorganic nutrients and C in spring and summer and primarily limited by C in autumn. Production responded more than biomass to increasing inputs of matter, whereas respiration did not change. The bacterial production response to increasing dissolved organic C load associated with riverine and atmospheric inputs was strongly related to the relative phosphorus (P) content of the dissolved matter concentrates. Our data suggest that bacterial production might decrease with the increase of P-deficient allochthonous matter inputs, which would have important biogeochemical consequences for C cycling in coastal areasThis research was supported by the Spanish Ministry of Science and Innovation through project REIMAGE (grants CTM2011-30155-C03-01 and CTM2011-30155-C03-02) and by the Xunta the Galicia trough project DIMENSION (grant EM2013/023). E. B-L was funded by a F.P.I. MICINN fellowship. M.N.-C. was funded by the CSIC Program "Junta para la Ampliación de Estudios" co-financed by the ESF. S.M.G. was funded by a Marie Curie fellowshipPeer reviewe

    Cerebrospinal Fluid Cytokines in Multiple System Atrophy: a Cross-Sectional Catalan MSA Registry Study

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    Introduction: Neuroinflammation is a potential player in neurodegenerative conditions, particularly the aggressive ones, such as multiple system atrophy (MSA). Previous reports on cytokine levels in MSA using serum or cerebrospinal fluid (CSF) have been inconsistent, including small samples and a limited number of cytokines, often without comparison to Parkinson's disease (PD), a main MSA differential diagnosis. Methods: Cross-sectional study of CSF levels of 38 cytokines using a multiplex assay in 73 participants: 39 MSA patients (19 with parkinsonian type [MSAp], 20 with cerebellar type [MSAc]; 31 probable, 8 possible), 19 PD patients and 15 neurologically unimpaired controls. None of the participants was under non-steroidal anti-inflammatory drugs at the time of the lumbar puncture. Results: There were not significant differences in sex and age among participants. In global non-parametric comparisons FDR-corrected for multiple comparisons, CSF levels of 5 cytokines (FGF-2, IL-10, MCP-3, IL-12p40, MDC) differed among the three groups. In pair-wise FDR-corrected non-parametric comparisons 12 cytokines (FGF-2, eotaxin, fractalkine, IFN-α2, IL-10, MCP-3, IL-12p40, MDC, IL-17, IL-7, MIP-1β, TNF-α) were significantly higher in MSA vs. non-MSA cases (PD + controls pooled together). Of these, MCP-3 and MDC were the most significant ones, also differed in MSA vs. PD, and were significant MSA-predictors in binary logistic regression models and ROC curves adjusted for age. CSF levels of fractalkine and MIP-1α showed a strong and significant positive correlation with UMSARS-2 scores. Conclusion: Increased CSF levels of cytokines such as MCP-3, MDC, fractalkine and MIP-1α deserve consideration as potential diagnostic or severity biomarkers of MSA.info:eu-repo/semantics/publishedVersio

    Hacia un modelo integral de accesibilidad en sistemas e-learning

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    Con el transcurso del tiempo, las actividades humanas, se han ido modificando, desde el ocio hasta el entablar una conversación, se vieron afectadas por la implementación de tecnologías. La educación, no está exceptuada, ya que cada día toman más impulso los sistemas de aprendizaje en línea mediados por tecnología, apuntando a una educación virtual, que se ha consolidado como una gran alternativa en los procesos de enseñanza-aprendizaje. En este sentido, esta línea de investigación plantea la importancia de incorporar condiciones de accesibilidad en los entornos virtuales de aprendizaje, a través de la definición de métricas a partir de la identificación de algunos criterios que permiten cuantificar el grado de satisfacción de los usuarios.Eje: Ingeniería de Software.Red de Universidades con Carreras en Informátic

    Community-Academic Partnership to implement a Breast and Cervical Cancer screening education program in Puerto Rico

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    To describe how a community-academic partnership between Taller Salud Inc., a community-based organization, and the Puerto Rico Community Cancer Control Outreach Program of the University of Puerto Rico was crucial in the adaptation and implementation of Cultivando La Salud (CLS), an evidence-based educational outreach program designed to increase breast and cervical cancer screening among Hispanic women living in Puerto Rico. This collaboration facilitated the review and adaptation of the CLS intervention to improve cultural appropriateness, relevance, and acceptability for Puerto Rican women

    Update of the cardiovascular disease policy model to predict cardiovascular events in Argentina

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    The Cardiovascular Disease Policy Model (CVDPM) is a computer simulation model used to represent and project future CVD mortality and morbidity. The objective was to update Argentina’s version of the CVDPM. For this purpose, information from the 2010 National Census, the 2013 National Risk Factor Survey, CESCAS I study, and PrEViSTA study were used to update the dynamics of population size, demographics, and cardiovascular disease (CVD) risk factor distributions over time. Results of the project are provided in model predictions and national statistics following calibration. Cardiovascular disease is the leading cause of death in Argentina

    Response of phytoplankton to enhanced atmospheric and riverine nutrient inputs in a coastal upwelling embayment

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    Original research paperOver the past decades, as a consequence of human activity, there was an increase in nutrient inputs to the ocean and they are expected to enhance even more in the future. Coastal areas, accounting for a significant proportion of marine primary productivity, are the most vulnerable zones to anthropogenic impacts. The response of phytoplankton communities to an increase in organic and inorganic nutrients levels from natural allochthonous sources was assessed in microcosm experiments conducted in a coastal system affected by intermittent upwelling events (Ría de Vigo, NW Iberia). Three nutrient addition experiments were performed in spring, summer and autumn, when surface water was supplemented with 5 and 10% of atmospheric and riverine matter. Pico-, nano- and microphytoplankton abundances, chlorophyll a concentration (Chl a) and primary production rates (PP) were measured and compared with those in the control seawater sample (without additions) after 48 h of incubation. Simultaneous experiments with controlled additions of inorganic and organic nutrients were also performed in order to describe the limiting nutrient for phytoplankton growth at each experiment. The composition of the matter inputs and the structure of the phytoplankton communities determined the type of response observed. Phytoplankton responses varied among seasons, being positively correlated with dissolved inorganic nitrogen (DIN) concentrations. As expected, the phytoplankton responses to external nutrient inputs were stronger under low nutrient levels (summer) than when phytoplankton was already growing in nutrient replete conditions (spring). Null and negative responses to the natural inputs were observed in autumn, which suggests that the oceanic phytoplankton advected to this coastal system during downwelling events could be occasionally inhibited by these nutrient inputs. In a future global change scenario, characterized by enhanced nutrient inputs from riverine and atmospheric origin, the response of phytoplankton communities will strongly depend on the concentration and chemical composition of these inputs and on the structure of phytoplankton communities able to respond to themSpanish Ministry of Science and Innovation (project REIMAGE CTM2011-30155); Spanish Ministry of Economy and Competitiviness (project iSmall, reference CTM2014-56119-R); Portuguese Foundation for Science and Technology (reference SFRH/BPD/188485/2015); ESF (reference JAE DOC 040) and MINECO (project FERMIO reference CTM2014-57334-JIN)Versión del edito

    The CD14 (−159 C/T) SNP is associated with sCD14 levels and allergic asthma, but not with CD14 expression on monocytes

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    LPS-ligation to CD14/TLR-4 on monocytes/macrophages triggers the production of IL-12-family cytokines. IL12/18 promote TH1-differentiation, counteracting the TH2-driven asthma. Therefore, CD14 modulation could alter the TH2-differentiation and should be taken into account when studying asthma. To analyse the alteration in CD14 levels and its association with CD14 (−159 C/T) SNP (rs2569190) in Caucasian adults with stable allergic asthma, we performed a cross-sectional study (277 healthy subjects vs. 277 patients) where clinical parameters, CD14 values and the CD14 (−159 C/T) SNP were studied. Apart from typical biomarkers, we found an increment of neuron-specific enolase (NSE) in allergic asthma, probably linked to monocyte activity. Indeed, we evidenced increased monocyte numbers, but lower CD14 expression and normalised sCD14 values in patients. Moreover, we noticed an association of the T allele (P = 0.0162) and TT genotype (P = 0.0196) of the CD14 SNP with a decreased risk of allergic asthma and augmented sCD14 levels. In conclusion, monocyte CD14 expression and normalized sCD14 values were reduced in stable state asthmatics, and this could be related to the presence of an expanded CD14low monocyte subset. This study also demonstrates that the CD14 (−159 C/T) polymorphism is a risk factor for moderate-severe allergic asthma in adult CaucasiansThis study was funded by grants from Sociedad Española de Neumología y Cirugía Torácica, (SEPAR) (121/2012) and Instituto de Salud Carlos III, Ministerio de Economía y Competitividad (Fondo de Investigación Sanitaria, FIS; co-financed by European Union ERDF funds) (PI13/02046). JJNF is a recipient of a Xunta de Galicia Fellowship (Co-financed by European Social Fund (ESF))S
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