294 research outputs found
Updating known distribution models for forecasting climate change impact on endangered species
To plan endangered species conservation and to design adequate management programmes, it is necessary to predict their
distributional response to climate change, especially under the current situation of rapid change. However, these
predictions are customarily done by relating de novo the distribution of the species with climatic conditions with no regard
of previously available knowledge about the factors affecting the species distribution. We propose to take advantage of
known species distribution models, but proceeding to update them with the variables yielded by climatic models before
projecting them to the future. To exemplify our proposal, the availability of suitable habitat across Spain for the endangered
Bonelli’s Eagle (Aquila fasciata) was modelled by updating a pre-existing model based on current climate and topography to
a combination of different general circulation models and Special Report on Emissions Scenarios. Our results suggested that
the main threat for this endangered species would not be climate change, since all forecasting models show that its
distribution will be maintained and increased in mainland Spain for all the XXI century. We remark on the importance of
linking conservation biology with distribution modelling by updating existing models, frequently available for endangered
species, considering all the known factors conditioning the species’ distribution, instead of building new models that are
based on climate change variables only.Ministerio de Ciencia e Innovación and FEDER (project CGL2009-11316/BOS
Linear response time-dependent density functional theory of the Hubbard dimer
The asymmetric Hubbard dimer is used to study the density-dependence of the
exact frequency-dependent kernel of linear-response time-dependent density
functional theory. The exact form of the kernel is given, and the limitations
of the adiabatic approximation utilizing the exact ground-state functional are
shown. The oscillator strength sum rule is proven for lattice Hamiltonians, and
relative oscillator strengths are defined appropriately. The method of Casida
for extracting oscillator strengths from a frequency-dependent kernel is
demonstrated to yield the exact result with this kernel. An unambiguous way of
labelling the nature of excitations is given. The fluctuation-dissipation
theorem is proven for the ground-state exchange-correlation energy. The
distinction between weak and strong correlation is shown to depend on the ratio
of interaction to asymmetry. A simple interpolation between carefully defined
weak-correlation and strong-correlation regimes yields a density-functional
approximation for the kernel that gives accurate transition frequencies for
both the single and double excitations, including charge-transfer excitations.
Many exact results, limits, and expansions about those limits are given in the
appendices.Comment: 22 pages, 14 figure
DFT-inspired methods for quantum thermodynamics
In the framework of quantum thermodynamics, we propose a method to
quantitatively describe thermodynamic quantities for out-of-equilibrium
interacting many-body systems. The method is articulated in various
approximation protocols which allow to achieve increasing levels of accuracy,
it is relatively simple to implement even for medium and large number of
interactive particles, and uses tools and concepts from density functional
theory. We test the method on the driven Hubbard dimer at half filling, and
compare exact and approximate results. We show that the proposed method
reproduces the average quantum work to high accuracy: for a very large region
of parameter space (which cuts across all dynamical regimes) estimates are
within 10% of the exact results
Climate and environmental monitoring for decision making
As human populations grow, so do the resource demands imposed on ecosystems and the impacts of our global footprint. Natural resources are not invulnerable, nor infinitely available. The environmental impacts of anthropogenic actions are becoming more apparent – air and water quality are increasingly compromised, pests and diseases are extending beyond their historical boundaries, and deforestation is exacerbating flooding downstream and loss of biodiversity. Society is increasingly becoming aware that ecosystem services are not only limited, but also that they are threatened by human activities. The need to better consider long-term ecosystem health and its role in enabling human habitation and economic activity is urgent. In this context IRI conducts research to understand the impact of climate and environmental changes on different sectors including agriculture, water management, human health, and natural disasters. Through exhaustive, rigorous evaluation, analysis and interpretation of remotely-sensed products and in-situ measurements, IRI ensures its partners have access to the most reliable and relevant information about the climate and environment in a format that best informs their decision making and planning. We focus on monitoring satellite-derived and in-situ estimates of precipitation, temperature, vegetation, water bodies, evapotranspiration, and land cover. Ultimately, the new products developed at IRI in partnership with other institutions at national (e.g. NOAA, NASA, USGS) and international (e.g. National Meteorology Agencies, UN FAO) levels are integrated into operational early-warning systems for health, natural disasters, agriculture, and food security. The new products which monitor in almost real-time climate and environmental conditions are made available through two online data bases at IRI called IRI Data Library and Map Room. In this paper we present the products developed at IRI and how they are integrated into Early Warning Systems (EWS). We also discuss IRI’s experience in linking EWS into decisions and policies using the fire early warning system as a concrete example
At the coalface and the cutting edge: general practitioners’ accounts of the rewards of engaging with HIV medicine
The interviews we conducted with GPs suggest that an engagement with HIV medicine enables clinicians to develop
strong and long-term relationships with and expertise
about the care needs of people living with HIV ‘at the
coalface’, while also feeling connected with a broader
network of medical practitioners and other professionals
concerned with and contributing to the ever-changing
world of science: ‘the cutting edge’. The general practice
HIV prescriber is being modelled here as the interface between these two worlds, offering a rewarding opportunity
for general practitioners to feel intimately connected to
both community needs and scientific change
Phosphoproteomic Analysis of Platelets in Severe Obesity Uncovers Platelet Reactivity and Signaling Pathways Alterations
OBJECTIVE: Obesity is associated with a proinflammatory and prothrombotic state that supports atherosclerosis progression. The goal of this study was to gain insights into the phosphorylation events related to platelet reactivity in obesity and identify platelet biomarkers and altered activation pathways in this clinical condition. APPROACH AND RESULTS: We performed a comparative phosphoproteomic analysis of resting platelets from obese patients and their age- A nd gender-matched lean controls. The phosphoproteomic data were validated by mechanistic, functional, and biochemical assays. We identified 220 differentially regulated phosphopeptides, from at least 175 proteins; interestingly, all were up-regulated in obesity. Most of the altered phosphoproteins are involved in SFKs (Src-family kinases)-related signaling pathways, cytoskeleton reorganization, and vesicle transport, some of them validated by targeted mass spectrometry. To confirm platelet dysfunction, flow cytometry assays were performed in whole blood indicating higher surface levels of GP (glycoprotein) VI and CLEC (C-type lectin-like receptor) 2 in platelets from obese patients correlating positively with body mass index. Receiver operator characteristics curves analysis suggested a much higher sensitivity for GPVI to discriminate between obese and lean individuals. Indeed, we also found that obese platelets displayed more adhesion to collagen-coated plates. In line with the above data, soluble GPVI levels-indicative of higher GPVI signaling activation-were almost double in plasma from obese patients. CONCLUSIONS: Our results provide novel information on platelet phosphorylation changes related to obesity, revealing the impact of this chronic pathology on platelet reactivity and pointing towards the main signaling pathways dysregulatedThis work was supported by the Spanish Ministry of Science and Innovation (grants No. SAF2016-79662-R, and PID2019-108727RB-I00), co-funded by the European Regional Development Fund (ERDF). Financial support from the Consellería de Cultura, Educación e Ordenación Universitaria, Xunta de Galicia (Centro Singular de investigación de Galicia accreditation 2019–2022, ED431G 2019/02; predoctoral grant 2018 Call) and the ERDF is also gratefully acknowledged. E.E. Gardiner and R.K. Andrews are supported by the National Health and Medical Research Council of Australia. The Proteomics Laboratory CSIC/UAB (Centro Superior de Investigaciones Científicas/Universidad Autónoma de Barcelona) is a member of Proteored, PRB3-ISCIII (Instituto de Salud Carlos III), and is supported by Grant PT17/0019/0008, funded by ISCIII and ERDF. L.A. Morán is supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 766118. S.P. Watson is supported by a BHF (British Heart Foundation) Chair (CH03/003)
V01 345. Implante de prótesis aórtica transcatéter por vía transaórtica: una alternativa de abordaje a las vías convencionales
Objetivosel implante de prótesis valvulares aórticas por vía transcatéter es una opción terapéutica reconocida en pacientes de alto riesgo quirúrgico. Nuestro objetivo es mostrar una vía de abordaje alternativa para su implante en algunos pacientes no candidatos para las vías usuales de acceso vascular periférico (femoral/subclavia) o transapical.Material y métodospresentamos el caso de un varón de 74 años con estenosis aórtica grave, CF IV y fracción de eyección del ventrículo izquierdo (FEVI) gravemente deprimida. Antecedentes de neoplasia de colon, diabetes mellitus tipo 2, enfermedad vascular periférica grave, cardiopatía isquémica crónica con revascularización percutánea mediante stents convencionales y neumonectomía derecha por carcinoma de pulmón. EuroSCORE logístico: 42,57%. Ecocardiograma: válvula aórtica trivalva (gradiente máximo 76, medio 51mmHg, área: 0,6cm2;, anillo: 24mm). Angiotomografía computarizada (angio-TC): grave ateromatosis ilíaca bilateral, desplazamiento importante del ápex cardíaco hacia la línea media y de la aorta ascendente hacia el hemitórax derecho. Cateterismo: ateromatosis grave de subclavia izquierda y estenosis grave de subclavia derecha, no reestenosis intra-stents.Se somete a implante de prótesis aórtica Core-Valve autoexpandible número 29 vía transaórtica (aorta ascendente) bajo visión directa a través de minitoracotomía anterior derecha por segundo espacio intercostal.Resultadosel paciente es extubado en 6h. Ecocardiograma de control: prótesis con apertura conservada e insuficiencia aórtica ligera-moderada. Ritmo sinusal estable.Conclusionesaunque la vía transaórtica mediante cirugía mínimamente invasiva está aún poco utilizada, en pacientes con alto riesgo para cirugía convencional puede ser una opción factible y segura para el implante de prótesis transcatéter en las que no sea posible el abordaje habitual
Determinants of Epstein-Barr virus-positive gastric cancer: an international pooled analysis
BACKGROUND: Meta-analyses of the published literature indicate that about 9% of gastric cancers contain Epstein-Barr virus (EBV), with consistent and significant differences by sex and anatomic subsite. This study aimed to identify additional determinants of EBV positivity and their joint effects.METHODS: From 15 international populations with consistent laboratory testing for EBV, we pooled individual-level data for 5081 gastric cancer cases including information on age, sex, subsite, histologic type, diagnostic stage, geographic region, and period of diagnosis. First, we combined population-specific EBV prevalence estimates using random effects meta-analysis. We then aggregated individual-level data to estimate odds ratios of EBV positivity in relation to all variables, accounting for within-population clustering.RESULTS: In unadjusted analyses, EBV positivity was significantly higher in males, young subjects, non-antral subsites, diffuse-type histology, and in studies from the Americas. Multivariable analyses confirmed significant associations with histology and region. Sex interacted with age (P = 0.003) and subsite (P = 0.002) such that male predominance decreased with age for both subsites. The positivity of EBV was not significantly associated with either stage or time period.CONCLUSION: Aggregating individual-level data provides additional information over meta-analyses. Distinguishing histologic and geographic features as well as interactions among age, sex, and subsite further support classification of EBV-associated gastric cancer as a distinct aetiologic entity. British Journal of Cancer (2011) 105, 38-43. doi: 10.1038/bjc.2011.215 www.bjcancer.com Published online 7 June 2011 (C) 2011 Cancer Research UKNational Cancer Institute, National Institutes of Healt
The Effect of Cash Flow on Investment: An Empirical Test of the Balance Sheet Channel
This paper tests the balance sheet theory, where the status of balance sheets affects the economy's response to monetary and other shocks. The theory predicts a positive effect of cash flow on investment, given fundamental determinants of investment. I use an empirical method developed by Gilchrist and Himmelberg (1995, 1999), which has previously only been used to study very large, publicly traded firms. In contrast, this paper uses a large Swedish data set with many smaller firms, where balance sheet effects are likely to be especially important. I find that a firm's cash flow has a positive impact on its investment, controlling for any information in cash flow about investment opportunities. As predicted by the balance sheet channel, the estimated effect of cash flow on investment is especially large for firms which, a priori, are more likely to be financially constrained (low-dividend, small and non-group firms). Moreover, the investment-cash flow sensitivity is significantly larger and more persistent during the first half of the sample period, which includes a severe banking crisis and recession, than during the second half
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