Local-scale models reveal ecological niche variability in amphibian and reptile communities from two contrasting biogeographic regions

Los modelos de nicho ecológico (ENMs) son ampliamente usados para describir cómo los factores ambientales influyen en la distribución de las especies. Su modelización en una escala local, frente a una gran escala dentro de un alto gradiente ambiental, pueden mejorar nuestra comprensión de los nichos ecológicos de las especies. El principal objetivo de este estudio es evaluar y comparar la contribución de variables ambientales ENMs de anfibios y reptiles en dos parques nacionales españoles ubicados en regiones biogeográficas contrastantes, es decir, el Mar Mediterráneo y la zona atlántica. Los ENMs fueron construidos con modelado de entropía máxima, utilizando 11 variables ambientales en cada territorio. Las contribuciones de estas variables para los modelos fueron analizadas y clasificadas utilizando diversos procedimientos estadísticos (U de Mann Whitney, análisis de componentes principales y modelos lineales generales). La distancia a la red hidrológica fue siempre la variable más relevante para ambos parques y clases taxonómicas. Las variables topográficas (es decir, la altitud y la pendiente) fueron la segunda variable más predictiva, seguida por las variables climáticas. Las diferencias en la variable de contribución fue observada entre los parques y las clases taxonómicas. Las variables relacionadas con la disponibilidad de agua, tuvieron la mayor contribución en los modelos del parque mediterráneo, mientras que la variable topográfica fue decisiva en el parque atlántico. Las curvas de respuesta específica a variables ambientales estaban de acuerdo con la afinidad biogeográfica de especies (Mediterráneo y no especies mediterráneas) y taxonomía (anfibios y reptiles). Curiosamente, estos resultados fueron observados para especies que se encuentran en ambos parques, particularmente los situados en sus límites. Nuestros resultados muestran que el modelo de nicho ecológico construidos a escala local revelan diferencias en las preferencias de hábitat dentro de un amplio gradiente ambiental. Por lo tanto, la modelización en escalas locales en lugar de asumir modelos a gran escala podría ser preferible para el establecimiento de estrategias de conservación de especies de reptiles en parques naturales.Ecological Niche Models (ENMs) are widely used to describe how environmental factors influence species distribution. Modelling at a local scale, compared to a large scale within a high environmental gradient, can improve our understanding of ecological species niches. The main goal of this study is to assess and compare the contribution of environmental variables to amphibian and reptile ENMs in two Spanish national parks located in contrasting biogeographic regions, i.e., the Mediterranean and the Atlantic area. The ENMs were built with maximum entropy modelling using 11 environmental variables in each territory. The contributions of these variables to the models were analysed and classified using various statistical procedures (Mann-Whitney U tests, Principal Components Analysis and General Linear Models). Distance to the hydrological network was consistently the most relevant variable for both parks and taxonomic classes. Topographic variables (i.e., slope and altitude) were the second most predictive variables, followed by climatic variables. Differences in variable contribution were observed between parks and taxonomic classes. Variables related to water availability had the larger contribution to the models in the Mediterranean park, while topography variables were decisive in the Atlantic park. Specific response curves to environmental variables were in accordance with the biogeographic affinity of species (Mediterranean and non-Mediterranean species) and taxonomy (amphibians and reptiles). Interestingly, these results were observed for species located in both parks, particularly those situated at their range limits. Our findings show that ecological niche models built at local scale reveal differences in habitat preferences within a wide environmental gradient. Therefore, modelling at local scales rather than assuming largescale models could be preferable for the establishment of conservation strategies for reptile species in natural parks.Trabajo financiado por: Universidad de Extremadura. Ayuda de Research Group Kraken Fundaçao para a Ciência e Tecnologia. Beca postdoctoral SFRH/BPD/73176/2010peerReviewe

Critical wetting of a class of nonequilibrium interfaces: A mean-field picture

A self-consistent mean-field method is used to study critical wetting transitions under nonequilibrium conditions by analyzing Kardar-Parisi-Zhang (KPZ) interfaces in the presence of a bounding substrate. In the case of positive KPZ nonlinearity a single (Gaussian) regime is found. On the contrary, interfaces corresponding to negative nonlinearities lead to three different regimes of critical behavior for the surface order-parameter: (i) a trivial Gaussian regime, (ii) a weak-fluctuation regime with a trivially located critical point and nontrivial exponents, and (iii) a highly non-trivial strong-fluctuation regime, for which we provide a full solution by finding the zeros of parabolic-cylinder functions. These analytical results are also verified by solving numerically the self-consistent equation in each case. Analogies with and differences from equilibrium critical wetting as well as nonequilibrium complete wetting are also discussed.Comment: 11 pages, 2 figure

Stochastic amplification of fluctuations in cortical up-states

Supporting Information: Appendix S1-S7Cortical neurons are bistable; as a consequence their local field potentials can fluctuate between quiescent and active states, generating slow 0.5-2 Hz oscillations which are widely known as transitions between Up and Down States. Despite a large number of studies on Up-Down transitions, deciphering its nature, mechanisms and function are still today challenging tasks. In this paper we focus on recent experimental evidence, showing that a class of spontaneous oscillations can emerge within the Up states. In particular, a non-trivial peak around 20 Hz appears in their associated power-spectra, what produces an enhancement of the activity power for higher frequencies (in the 30-90 Hz band). Moreover, this rhythm within Ups seems to be an emergent or collective phenomenon given that individual neurons do not lock to it as they remain mostly unsynchronized. Remarkably, similar oscillations (and the concomitant peak in the spectrum) do not appear in the Down states. Here we shed light on these findings by using different computational models for the dynamics of cortical networks in presence of different levels of physiological complexity. Our conclusion, supported by both theory and simulations, is that the collective phenomenon of >stochastic amplification of fluctuations> - previously described in other contexts such as Ecology and Epidemiology - explains in an elegant and parsimonious manner, beyond model-dependent details, this extra-rhythm emerging only in the Up states but not in the Downs. © 2012 Hidalgo et al.Funding provided by Spanish MICINN-FEDER under project FIS2009-08451 and Junta de Andalucia Proyecto de Excelencia P09FQM-4682. L.S. acknowledges the financial support of Fundacion P. Barrie de la Maza and funding grant 01GQ1001A.Peer Reviewe

Analyzing climate variations at multiple timescales can guide Zika virus response measures

Background: The emergence of Zika virus (ZIKV) in Latin America and the Caribbean in 2014–2016 occurred during a period of severe drought and unusually high temperatures, conditions that have been associated with the 2015–2016 El Niño event, and/or climate change; however, no quantitative assessment has been made to date. Analysis of related flaviviruses transmitted by the same vectors suggests that ZIKV dynamics are sensitive to climate seasonality and longer-term variability and trends. A better understanding of the climate conditions conducive to the 2014–2016 epidemic may permit the development of climate-informed short and long-term strategies for ZIKV prevention and control. Results: Using a novel timescale-decomposition methodology, we demonstrate that the extreme climate anomalies observed in most parts of South America during the current epidemic are not caused exclusively by El Niño or climate change, but by a combination of climate signals acting at multiple timescales. In Brazil, the dry conditions present in 2013–2015 are primarily explained by year-to-year variability superimposed on decadal variability, but with little contribution of long-term trends. In contrast, the warm temperatures of 2014–2015 resulted from the compound effect of climate change, decadal and year-to-year climate variability. Conclusions: ZIKV response strategies made in Brazil during the drought concurrent with the 2015-2016 El Niño event, may require revision in light of the likely return of rainfall associated with the borderline La Niña event expected in 2016–2017. Temperatures are likely to remain warm given the importance of long term and decadal scale climate signals. Keywords: Zika virus Epidemic Climate Climate change Decadal Inter-annual El Niño Brazil Drought Vector contro

Cross-time scales interactions and rainfall extreme events in southeastern South America for the austral summer. Part II: predictive skill

Potential and real predictive skill of the frequency of extreme rainfall in southeastern South America for the December–February season are evaluated in this paper, finding evidence indicating that mechanisms of climate variability at one time scale contribute to the predictability at another scale; that is, taking into account the interference of different potential sources of predictability at different time scales increases the predictive skill. Part I of this study suggested that a set of daily atmospheric circulation regimes, or weather types, was sensitive to these cross–time scale interferences, conducive to the occurrence of extreme rainfall events in the region, and could be used as a potential predictor. At seasonal scale, a combination of those weather types indeed tends to outperform all the other candidate predictors explored (i.e., sea surface temperature patterns, phases of the Madden–Julian oscillation, and combinations of both). Spatially averaged Kendall’s t improvements of 43% for the potential predictability and 23% for real-time predictions are attained with respect to standard models considering sea surface temperature fields alone. A new subseasonal-to-seasonal predictive methodology for extreme rainfall events is proposed based on probability forecasts of seasonal sequences of these weather types. The cross-validated real-time skill of the new probabilistic approach, as measured by the hit score and the Heidke skill score, is on the order of twice that associated with climatological values. The approach is designed to offer useful subseasonal-to-seasonal climate information to decision-makers interested not only in how many extreme events will happen in the season but also in how, when, and where those events will probably occur

The association between the weight of schoolbags and low back pain among schoolchildren: A systematic review, meta‐analysis and individual patient data meta‐analysis

[EN] Background The objective of this study was to determine whether carrying a heavy schoolbag is associated to a higher prevalence of low back pain (LBP). Methods A systematic review and meta-analysis was conducted (PROSPERO, CRD42018077839). Observational studies analysing the relationship between schoolbag weight and LBP, were searched for in 20 electronic databases and 12 specialized journals until February 28th, 2019, without date or language restrictions. All studies which included ≥ 50 subjects aged 9 to 16, were reviewed. Methodological quality was assessed by two reviewers separately, using validated tools. A meta-analysis and an individual patient data (IPD) meta-analysis were conducted to examine the relationship between schoolbag weight and LBP. Certainty of evidence was assessed using an adapted GRADE methodology. Results 5,524 citations were screened, 21 studies (18,296 subjects) were reviewed and 11 studies (9,188 subjects) were included in the meta-analysis. The IPD meta-analysis included 9,188 subjects from seven studies. Among the 21 studies reviewed, the mean score for methodological quality was 78.3 of 100. Only one study suggested an association between heavier schoolbags and LBP. Neither the meta-analysis nor the IPD meta-analysis found an association between carrying schoolbags weighing > 10% of bodyweight, and LBP. No differences based on age, gender or sport activity were found. Discussion Available evidence does not support that schoolbags weighing > 10% of bodyweight are associated with a higher prevalence of LBP among schoolchildren aged 9–16. The certainty of evidence is low. Further research is required on the relationship between schoolbag weight and LBP. Significance This systematic review, with a meta-analysis and an IPD meta-analysis, failed to find a link between schoolbags weighing ≥ 10% of body weight and LBP among schoolchildren aged 9 to 16. Further longitudinal studies, with large samples, long follow-up periods, and rigorous methods taking into account duration of carry and the physical capacity of each subject, are required in this field.S

Validación de la escala CRUSADE para evaluar el riesgo de sangrado en pacientes con infarto agudo de miocardio sin elevación del ST

ResumenObjetivoEvaluar si la escala CRUSADE es aplicable en la comunidad colombiana.MétodosSe realizó un estudio de validación externa dentro de una cohorte histórica, en el que se incluyeron pacientes hospitalizados entre los años 2006 y 2012 en el Hospital Universitario San Ignacio, en Bogotá, Colombia. Se tomaron historias clínicas de pacientes mayores de 18 años, que tuvieran asignado el diagnóstico de infarto agudo de miocardio sin supradesnivel del ST. Se comparó el número de eventos (sangrado) predichos y observados durante la hospitalización (calibración). Finalmente, se estimó la capacidad para separar sujetos de alto y bajo riesgo (discriminación).ResultadosSe incluyeron 252 pacientes. El número de eventos mayores fue 30 (11,9%) y el de eventos menores 23 (9,12%); 12 pacientes (7,46%) fallecieron. En el grupo de muy alto riesgo (más de 50 puntos de la escala), se reportó el mayor número de eventos (respecto a la población estudiada). Al evaluar la escala se evidenció una buena capacidad de calibración (X2 p=0,84); sin embargo, la discriminación no fue adecuada (área bajo la curva 0,6128 [IC 95% 0,46-0,76]).ConclusionesSe encontraron pocos eventos, si bien los datos sugieren que la escala subestima levemente los riesgos. La escala tiene buena calibración, pero no posee capacidad de discriminación adecuada, hecho que probablemente obedece a que se obtuvo un pequeño número de eventos, con desviaciones estándar altas. Por tanto, se requieren estudios adicionales, con mayor poder estadístico.AbstractObjectiveTo assess whether CRUSADE scale is applicable in the Colombian community.MethodsA study of external validation in a historical cohort, which included patients hospitalized between 2006 and 2012 in the Hospital Universitario San Ignacio in Bogota Colombia, was performed. Medical records of patients older than 18 years, who had been diagnosed as acute myocardial infarction without ST segment elevation, were included. The number of events (bleeding) predicted and observed during hospitalization (calibration) were compared. Finally, the ability to separate subjects at high and low risk (discrimination) was estimated.Results252 patients were included. The number of major events was 30 (11.9%) and that of minor events 23 (9.12%); 12 patients (7.46%) died. In the group of very high risk (more than 50 points on the scale), the largest number of events (regarding the study population) was reported. At assessing the scale, a good calibration capacity was evidenced (X2 p=.84); however, discrimination was not adequate (0.6128 AUC [95% CI 0.46 to 0.76]).ConclusionsFew events were found, although the data suggest that the scale slightly underestimates the risks. The scale has good calibration, but lacks adequate discriminatory capacity, probably due to the fact that a small number of events with high standard deviations were obtained. Therefore, further studies with greater statistical power are required

Complement Binding Anti-HLA Antibodies and the Survival of Kidney Transplantation

Background: Antibody-mediated rejection (AMR) is one of the most important challenges in the context of renal transplantation, because the binding of de novo donor-specific antibodies (dnDSA) to the kidney graft triggers the activation of the complement, which in turn leads to loss of transplant. In this context, the objective of this study was to evaluate the association between complement-fixing dnDSA antibodies and graft loss as well as the possible association between non-complement-fixing antibodies and transplanted organ survival in kidney transplant recipients. Methods: Our study included a cohort of 245 transplant patients over a 5-year period at Virgen de las Nieves University Hospital (HUVN) in Granada, Spain. Results: dnDSA was observed in 26 patients. Of these patients, 17 had non-complement-fixing dnDSA and 9 had complement-fixing dnDSA. Conclusions: Our study demonstrated a significant association between the frequency of rejection and renal graft loss and the presence of C1q-binding dnDSA. Our results show the importance of the individualization of dnDSA, classifying them according to their ability to activate the complement, and suggest that the detection of complement-binding capacity by dnDSA could be used as a prognostic marker to predict AMR outcome and graft survival in kidney transplant patients who develop dnDSA

Global stability analysis of axisymmetric liquid-liquid flow focusing

Article number A10We analyse both numerically and experimentally the stability of the steady jetting tip streaming produced by focusing a liquid stream with another liquid current when they coflow through the orifice of an axisymmetric nozzle. We calculate the global eigenmodes characterizing the response of this configuration to small-amplitude perturbations. In this way, the critical conditions leading to the instability of the steady jetting tip streaming are determined. The unstable perturbations are classified according to their oscillatory character and to the region where they originate (convective and absolute instability). We derive and explain in terms of the velocity field a simple scaling law to predict the diameter of the emitted jet. The numerical stability limits are compared with experimental results, finding reasonable agreement. The experiments confirm the existence of the two instability mechanisms predicted by the global stability analysisMinisterio de Economía, Industria y Competitividad (España) DPI2016-78887Junta de Extremadura GR18175Junta de Andalucía P18-FR-362

Microstructure and tensile properties of oxide dispersion strengthened Fe–14Cr– 0.3Y₂O₃ and Fe–14Cr–2W–0.3Ti–0.3Y₂O₃

Proocedings of: 15th International Conference on Fusion Reactor Materials (ICFRM15). Charleston, South Carolina (United States of America), 16-22 october, 2011Two ODS ferritic steels with nominal compositions (wt.%): Fe–14Cr–0.3Y2O3 and Fe–14Cr–2W–0.3Ti–0.3Y2O3 have been produced by mechanical alloying and consolidation by hot isostatic pressing. The microstructure and tensile properties of these materials after being forged and heat treated at 1123 K have been investigated to clarify the interrelation between composition, microstructure and mechanical properties. The second phase precipitates in these alloys have been analyzed by high angle annular dark field imaging in scanning TEM mode and electron diffraction. Fe–14Cr–2W–0.3Ti–0.3Y2O3 exhibits a duplex microstructure consisting of large recrystallized grains, as large as 1.5 μm, and unrecovered regions containing submicron equiaxed grains. In addition, three types of secondary phase particles have been found: large M₂₃C₆ particles containing W and Cr, (Cr + Ti) rich spherical particles with diameters between 50 and 500 nm, and fine (Y + Ti) oxide particles with sizes below 30 nm. In contrast, Fe14CrY shows a uniform structure of equiaxed grains, with sizes in the range 0.5 3 μm, containing a fine disper sion of Y oxide particles (<30 nm) homogeneously distributed inside the grains, as well as large carbide and oxide particles. Tensile tests performed over the temperature range 273 973 K have revealed that the alloy containing W and Ti has lower yield and tensile strengths than Fe–14Cr–0.3Y2O3 at tempera tures up to 773 K, but the opposite appears to occur beyond this temperature.This investigation was supported by the Spanish Ministry of Science and Innovation (Project No. ENE 2008 06403 C06 04 and Juan de la Cierva program), the Comunidad de Madrid through the program ESTRUMAT CM (Grant S0505/MAT/0077), and the European Commission through the European Fusion Development Agreement (Contract No. 09 240), the IP3 FP6 ESTEEM project (Contract No. 026019) and the Fusion Energy Materials Science (FEMaS) FP7 coordination action.Publicad