Macroecology and ecoinformatics: evaluating the accuracy of the ecological niche models calibrated with species occurrence data with biases and/or errors

Hoy en día es común estudiar los patrones globales de biodiversidad a partir de las predicciones generadas por diferentes modelos de nicho ecológico. Habitualmente, estos modelos se calibran con datos procedentes de bases de datos de libre acceso (e.g. GBIF). Sin embargo, a pesar de la facilidad de descarga y de la accesibilidad de los datos, la información almacenada sobre las localidades donde están presentes las especies suele tener sesgos y errores. Estos problemas en los datos de calibración pueden modificar drásticamente las predicciones de los modelos y con ello pueden enmascarar los patrones macroecológicos reales. El objetivo de este trabajo es investigar qué métodos producen resultados más precisos cuando los datos de calibración incluyen sesgos y cuáles producen mejores resultados cuando los datos de calibración tienen, además de sesgos, errores. Para ello creado una especie virtual, hemos proyectado su distribución en la península ibérica, hemos muestreado su distribución de manera sesgada y hemos calibrado dos tipos de modelos de distribución (Bioclim y Maxent) con muestras de distintos tamaños. Nuestros resultados indican que cuando los datos sólo están sesgados, los resultados de Bioclim son mejores que los de Maxent. Sin embargo, Bioclim es extremadamente sensible a la presencia de errores en los datos de calibración. En estas situaciones, el comportamiento de Maxent es mucho más robusto y las predicciones que proporciona son más ajustadas.In spite of the biases and errors of the open access biodiversity databases we need to take advantage of the occurrences stored in those databases for analyzing the global patterns of biodiversity. Here, we aimed to test which modelling method produces better predictions when calibrated with data samples that have biases and errors. We tested two different methods, a complex one, Maxent, and a simple one, Bioclim. We created a virtual species, sampled its distribution with both, bias and errors, and calibrated the models with those samples. Results indicated that Bioclim produces better predictions than Maxent when calibrated with biased data sets. Bioclim did not overestimate the species’ range and it was able to produce accurate predictions even when calibrated with small and biased data samples (25-50 points). However, when wrong occurrences were included in the calibration samples, Bioclim over-predicted the species’ range. Our experiments indicated that in that case, Maxent predictions remained robust and provided accurate maps. Thus, if the calibration data samples have just biases, Bioclim provided better maps than Maxent. However, when samples have both, biases and wrong occurrences, Maxent model provided better results than Bioclim.Este trabajo se enmarca dentro de los proyectos: “Support of establishment, development and mobility of quality research teams at the Charles University” CZ.1.07/2.3.00/30.0022, financiado por la European Science Foundation y la República Checa (S.Varela); y “Potential effects of climate change on Natura 2000 conservation targets in Castilla-La Mancha (CLICHE)” (Ref. no.: POIC10-0311-0585), financiado por el gobierno de Castilla La-Mancha, España (S. Varela, R. G. Mateos, R. García-Valdés, and F. Fernández-González)

Exact Relativistic Static Charged Dust Disks and Non-axisymmetric Structures

The well-known ``displace, cut and reflect'' method used to generate disks from given solutions of Einstein field equations is applied to the superposition of twoextreme Reissner-Nordstrom black holes to construct disks made of charged dust and alsonon-axisymmetric planar distributions of charged dust on the z=0 plane. They are symmetric with respect to twoor one coordinate axes, depending whether the black holes have equal or unequal masses, respectively.For these non-axisymmetric distributions of matter we also study the effective potential for geodesic motion of neutral test particles.Comment: Classical and Quantum Gravity (in press). 15 pages, LaTex, 8 .eps fig

Hydrological structures along the N y NW Iberian Shelf during the winter-spring transition

ECOPE

Seagrass Patch Complexity Affects Macroinfaunal Community Structure in Intertidal Areas: An In Situ Experiment Using Seagrass Mimics

[EN] Seagrasses, as key ecosystem engineers in coastal ecosystems, contribute to enhancing diversity in comparison with nearby bare areas. It has been proved mainly for epifauna, but data on infauna are still scarce. The present study addresses how seagrass structural complexity (i.e., canopy properties) affects the diversity of infaunal organisms inhabiting those meadows. Canopy attributes were achieved using seagrass mimics, which were used to construct in situ vegetation patches with two contrasting canopy properties (i.e., shoot density and morphology) resembling the two seagrass species thriving in the inner Cadiz Bay: Zostera noltei and Cymodocea nodosa. After three months, bare nearby areas, two mimicked seagrass patches (‘Zostera’ and ‘Cymodocea’), and the surrounding natural populations of Zostera noltei were sampled in a spatially explicit way. Shifts in organism diets were also determined using15N and13C analyses in available food sources and main infaunal organisms, mixing models, and niche metrics (standard ellipse area). Seagrass-mimicked habitats increased the species richness (two-fold), organism abundance (three to four times), and functional diversity compared with bare nearby areas. The clam Scrobicularia plana (deposit/filter feeder) and the worm Hediste diversicolor (omnivore) were dominant in all of the samples (> 85%) and showed an opposite spatial distribution in the reconstructed patches: whilst S. plana accumulated in the outer-edge parts of the meadow, H. diversicolor abounded in the center. Changes in the isotopic signature of both species depending on the treatment suggest that this faunal distribution was associated with a shift in the diet of the organisms. Based on our results, we concluded that facilitation processes (e.g., reduction in predation and in bioturbation pressures) and changes in food availability (quality and quantity) mediated by seagrass canopies were the main driving forces structuring this community in an intertidal muddy area of low diversitySIThis work was supported by the Spanish Project PAVAROTTI (CTM2017-85365-R) from the Ministry of Science and Innovation and by the Junta de Andalucía Excellence Project PAMBIO (P08-RNM-03783

The use of clinical guidelines for referral of patients with lesions suspicious for oral cancer may ease early diagnosis and improve education of healthcare professionals

Early diagnosis and referral of oral cancer is essential. Successful implementation of clinical guidelines must include current practitioners and students. Objective: To evaluate the diagnostic accuracy of students at oral cancer screening and to assess the effectiveness of clinical referral guidelines. Study Design: Fifth year dental students were randomly allocated to either control (n=19) or experimental groups (n=18). Both received the customary training in oral diagnosis. The experimental group underwent a 2 hour workshop where the guidelines for the referral of suspicious lesions were discussed. Three months later, a set of 51 clinical cases including benign, malignant, and precancerous conditions/lesions were used to assess the screening ability of each subject. Results: All 37 students entered the study. Sensitivity (control group) ranged from 16.7% to 66.7%; the experimental group scored from 16.7% to 83.3%. Fifty percent of the experimental students reached sensitivity values ?62.5% (p=0.01). Diagnostic specificity (control group) spanned from 80% to 93.3% (median=50%); amongst experimental group it ranged from 82.2% to 97.8% (median=92.8%); (p=0.003). Concordance -control group- was X=82.5 (SD=3.2), and X=88.2 (SD=4.3) for the experimental, (p>0.001). Cohen's kappa test was poor (K<0.40) for the controls and moderate for the experimental group. The experimental group referred more oral cancers urgently (p=0.002) and left less unreferred cancers (0.04). This group also referred more precancerous lesions/conditions urgently (p=0.02). Conclusions: The implementation of a clinical referral guideline at undergraduate level has proved valuable, under experimental conditions, to significantly increase diagnostic abilities of the examiners and thus to improve screening for oral cancer. © Medicina Oral S. L

Títulos de anticuerpos contra Leptospira sp., en primates del zoológico Matecaña, Pereira, Colombia

RESUMEN Objetivo. Identificar los serovares más frecuentes de Leptospira sp., por la técnica de Microaglutinación (MAT) en una población de primates neotropicales, mantenida en condiciones de cautiverio, y evaluar por microscopía de campo oscuro la presencia de espiroquetas en aguas para el consumo de los animales. Materiales y métodos. Se realizó un estudio de prevalencia de punto en 65 monos neotropicales, mediante la técnica de Microaglutinación Macroscópica (MAT) usando un cepario de referencia conformado por 21 serovares de Leptospira sp., y la observación de espiroquetas en el agua mediante microscopía de campo oscuro. Resultados. La seroprevalencia de Leptospira sp., en los monos neotropicales fue del 41.5% (27/65). Los serovares de Leptospira Autumnalis (25%), Ranarum (22.9%), Icterohaemorrhagiae (12.5%), Pomona (12.5%) y Australis (10.4%) fueron los más aglutinados por los sueros. Los monos ardilla (Saimiri sciureus), lanudo (Lagothrix lagotricha) y tití pielroja (Saguinus oedipus) fueron seronegativos. Se observaron espiroquetas en el agua evaluada. Conclusiones. Se evidencia la circulación de Leptospira sp., en el zoológico, siendo necesario la implementación de estrategias de vigilancia epidemiológica activa y programas de promoción

Three decades of continuous ocean observations in North Atlantic Spanish waters: The RADIALES time series project, context, achievements and challenges

Ship-based time-series observations provide crucial data for understanding marine ecosystems, improving decision making in ocean and coastal management. However, only a few time series survive for more than a decade. RADIALES is one of the longest multidisciplinary programs in operation in the northern and northwestern coast of Spain. In the last 30 years, this program collected monthly data on physical, chemical and plankton observations in an array of five sections of stations representative of upwelling and stratified dynamics. Here, the main achievements, including key contributions to ecosystem conservation policies, are summarized. The development of this program, in line with similar initiatives in other countries, included phases focused on the study of seasonality, on comparative analysis, and lately on the analysis of decadal variability and regime shifts. Furthermore, in recent years there was a substantial improvement in the identification of plankton species by genomics. Among the main findings of RADIALES are the quantification of ocean warming at subsurface layers, the determination of climatologies in thermohaline, biogeochemical and biological variables, the inventory of plankton species (from bacteria to zooplankton) and the identification of regionally coherent regime shifts. Baselines defined by RADIALES series were instrumental for the assessment of environmental impacts (e.g. oil spills) and for the support of environmental policies (e.g. Marine Strategy Framework Directive). By contributing to international databases, data from programs as RADIALES combined with new instrumental observations will help to develop a more coherent and comprehensive understanding of the ocean ecosystems, enhancing our ability to detect and forecast risks.IEO, GAIN (Xunta de Galicia)Versión del editor3,26

SAR studies of epoxycurcuphenol derivatives on leukemia CT-CD4 cells

Bioactive natural products are a potential source of new pharmaceuticals since they offer new modes of action and more specific activities. The use of derivatization also enables the optimal structure for their biological activity to be determined. In this study several epoxycurcuphenol derivatives were synthesized. The substitution pattern on the aromatic and oxirane rings was varied along with that at the benzylic position and the length of the side chain was altered. These changes were made in order to gain a deeper understanding of the structural requirements for activity. The biological activities of these compounds were evaluated on the human leukemia cell line Jurkat using an antiproliferative assay. The activity results and structural requirements are discussed

The role of family in the intergenerational transmission of collective action

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordThe present research demonstrates intergenerational influences on collective action participation, whereby parents’ past and current participation in collective action (descriptive family norms) shape their children’s participation in conventional and radical collective action via injunctive family norms (perception that parents value such participation). Two unique data sets were used: dyads of activist parents and their adult children (Study 1, N = 100 dyads) and student activists who participated in a yearlong, three-wave longitudinal study (Study 2, Ns wave 1 = 1,221, Wave 2 = 960, and Wave 3 = 917). Parents’ past and current participation directly and indirectly predicted children’s protest participation in Study 1, while Study 2 showed a similar pattern longitudinally: Perceptions of parents’ participation (descriptive family norm) and approval (injunctive family norm) predicted change in collective action participation over time. Together, results highlight family environment as a critical setting for the intergenerational transmission of protest

Mechanical compartmentalization of the intestinal organoid enables crypt folding and collective cell migration

Intestinal organoids capture essential features of the intestinal epithelium such as crypt folding, cellular compartmentalization and collective movements. Each of these processes and their coordination require patterned forces that are at present unknown. Here we map three-dimensional cellular forces in mouse intestinal organoids grown on soft hydrogels. We show that these organoids exhibit a non-monotonic stress distribution that defines mechanical and functional compartments. The stem cell compartment pushes the extracellular matrix and folds through apical constriction, whereas the transit amplifying zone pulls the extracellular matrix and elongates through basal constriction. The size of the stem cell compartment depends on the extracellular-matrix stiffness and endogenous cellular forces. Computational modelling reveals that crypt shape and force distribution rely on cell surface tensions following cortical actomyosin density. Finally, cells are pulled out of the crypt along a gradient of increasing tension. Our study unveils how patterned forces enable compartmentalization, folding and collective migration in the intestinal epithelium