83 research outputs found
Maximum likelihood methods and their application in neighbourhood models
Los métodos de máxima verosimilitud (MMV) ofrecen un marco alternativo a la estadística frecuentista convencional, alejándose del uso del p-valor para el rechazo de una única hipótesis nula y optando por el uso de las verosimilitudes para evaluar el grado de apoyo en los datos a un conjunto de hipótesis alternativas (o modelos) de interés para el investigador. Estos métodos han sido ampliamente aplicados en ecología en el marco de los modelos de vecindad. Dichos modelos usan una aproximación espacialmente explícita para describir procesos demográficos de plantas o procesos ecosistémicos en función de los atributos de los individuos vecinos. Se trata por tanto de modelos fenomenológicos cuya principal utilidad radica en funcionar como herramientas de síntesis de los múltiples mecanismos por los que las especies pueden interactuar e influenciar su entorno, proporcionando una medida del efecto per cápita de individuos de distintas características (ej. tamaño, especie, rasgos fisiológicos) sobre los procesos de interés. La gran ventaja de aplicar los MMV en el marco de los modelos de vecindad es que permite ajustar y comparar múltiples modelos que usen distintos atributos de los vecinos y/o formas funcionales para seleccionar aquel con mayor soporte empírico. De esta manera, cada modelo funcionará como un “experimento virtual” para responder preguntas relacionadas con la magnitud y extensión espacial de los efectos de distintas especies coexistentes, y extraer conclusiones sobre posibles implicaciones para el funcionamiento de comunidades y ecosistemas. Este trabajo sintetiza las técnicas de implementación de los MMV y los modelos de vecindad en ecología terrestre, resumiendo su uso hasta la fecha y destacando nuevas líneas de aplicación.Maximum likelihood methods (MLM) offer an alternative framework to the traditional frequentist approach of data analysis, where the use of p-values to reject a single null (usually trivial) hypothesis is replaced by the use of likelihoods to evaluate the support in the data for a set of alternative working hypotheses of scientific relevance. These methods have been widely applied in the ecological framework of the neighbourhood models. These models use a spatially-explicit approach to describe demographic or ecosystem processes as a function of the attributes of neighbouring plants. They are therefore phenomenological models that serve as a tool of synthesis of the multiple mechanisms by which species can interact and modify its immediate environment, offering an estimate of the per-capita influence of individuals of different characteristics (e.g. size, species, functional traits) on the processes of study. A fundamental advantage of applying MMV in the framework of the neighbourhood models is that it allows fitting and comparing multiple models that use contrasting neighbour attributes and/or functional forms to select the one with the largest empirical support. In this way, each model works as a “virtual experiment” to answer questions related with the magnitude and spatial extent of the effects of different coexisting species and their potential implications for the function of communities and ecosystems. This paper reviews the use of MMV and neighborhood models in terrestrial ecology, synthesizing the state of the art and emphasizing new avenues of application
Steric, Activation Method and Solvent Effects on the Structure of Paddlewheel Diruthenium Complexes
Conventional heating and solvothermal synthetic methods (with or without microwave activation) have been used to study the reaction of o-, m- and p-methoxybenzoic acid with [Ru2Cl(μ-O2CMe)4]. The tetrasubstituted series [Ru2Cl(µ-O2CC6H4-R)4], with R = o-OMe, m-OMe and p-OMe, has been prepared by the three procedures. Depending on the synthetic method and the experimental conditions, three compounds have been isolated (1a, 1b, 1c) with the o-methoxybenzoate ligand. However, with the m- and p-methoxybenzoate ligands, only the complexes 2 and 3 have been obtained, respectively. Compound 1a, with stoichiometry [Ru2Cl(µ-O2CC6H4-o-OMe)4]n, shows a polymeric structure with the chloride ions bridging the diruthenium units to form linear chains. Compounds 2 and 3, with the same stoichiometry, predictably form zig-zag chains in accordance with their insolubility and their magnetic measurements. Compound 1b, [Ru2Cl(µ-O2CC6H4-o-OMe)4(EtOH)], is a discrete molecular species with a chloride ion and one ethanol molecule occupying the axial positions of the dimetallic unit. Compound 1c is a cation-anion complex, [Ru2(µ-O2CC6H4-o-OMe)4(MeOH)2][Ru2Cl2(µ-O2CC6H4-o-OMe)4]. The cationic complex has two solvent molecules at the axial positions whereas the anionic complex has two chloride ligands at these positions. Complexes have been characterized by elemental analyses, mass spectrometry and IR and UV-vis-NIR spectroscopies. A magnetic study of complexes 1a, 1b, 2 and 3 have also been carried out. The crystal structure of compounds 1b and 1c have been solved by single X-ray crystal methods
Understanding microRNAs in the Context of Infection to Find New Treatments against Human Bacterial Pathogens
[EN] The development of RNA-based anti-infectives has gained interest with the successful
application of mRNA-based vaccines. Small RNAs are molecules of RNA of <200 nucleotides in
length that may control the expression of specific genes. Small RNAs include small interference RNAs
(siRNAs), Piwi-interacting RNAs (piRNAs), or microRNAs (miRNAs). Notably, the role of miRNAs
on the post-transcriptional regulation of gene expression has been studied in detail in the context of
cancer and many other genetic diseases. However, it is also becoming apparent that some human
miRNAs possess important antimicrobial roles by silencing host genes essential for the progress
of bacterial or viral infections. Therefore, their potential use as novel antimicrobial therapies has
gained interest during the last decade. The challenges of the transport and delivery of miRNAs
to target cells are important, but recent research with exosomes is overcoming the limitations in
RNA-cellular uptake, avoiding their degradation. Therefore, in this review, we have summarised the
latest developments in the exosomal delivery of miRNA-based therapies, which may soon be another
complementary treatment to pathogen-targeted antibiotics that could help solve the problem caused
by multidrug-resistant bacteriaSIWe thank the Junta de Castilla y León (Spain) for funding our research work on microRNAs, grant number LE044P20. A.M. is supported with a postdoctoral fellowship “Margarita Salas”. M.L. is the recipient of a “Beatriz Galindo” grant (Ref. BEAGAL18/00068 - BGP18/00033
Mechanisms of coronavirus pathogenicity and virus-host interactions
Trabajo presentado en la Conference on the Cooperation and Collaboration on Prevention and Control of Animal Diseases, celebrada en Hangzhou (China), del 21 al 23 de mayo de 2019Coronaviruses (CoVs) are important human and animal pathogens mainly causing respiratory and enteric infections with
diverse severity. The presence of CoVs in bats, as animal reservoirs, and their ability for interspecies transmission have recently led to the emergence of novel CoVs responsible for epidemics in humans and livestock.
In order to develop protection strategies against CoV infections, our laboratory is interested in the identification of (i)
Viral factors involved in virulence and (ii) Host signaling pathways contributing to pathogenesis, using human coronaviruses SARS- and MERS-CoVs as model systems
Una estética de la vivienda de interés social: desarrollos progresivos en Palmira, Colombia (2000-2017)
This case study explores the progressive development of social housing projects in the city of Palmira (Colombia) between 2000 and 2017. Here particular attention is paid to aesthetic parameters through three main concepts: perception, form and function. The methodological approach brought together four qualitative tools for data gathering and analysis: document review, field observations (field diaries, notes and photographic record); interviews (with users representatives of constructors and public servants), and; the development of urban profiles. The findings suggest that social housing units constitute an unfinished project, that, shaped by the subjectivity of their inhabitants’, generates conflict with public spaces. Despite their diversity, the interventions follow identifiable patterns, commonly linked to inadequacies in the original designs.Este estudio de caso explora los desarrollos progresivos de la vivienda de interés social (VIS) en la ciudad de Palmira (Colombia) entre los años 2000 y 2017, prestando particular atención a su dimensión estética, a partir de tres ejes fundamentales: percepción, forma y función. La aproximación metodológica agrupó cuatro herramientas cualitativas de recolección y análisis de datos: revisión documental, observación in situ (diarios de campo, levantamientos y registro fotográfico), entrevistas (a usuarios, representantes de constructoras y servidores públicos) y desarrollo de perfiles urbanos. Los hallazgos sugieren que la VIS constituye un proyecto inacabado, que, determinado por la subjetividad de los habitantes, genera relaciones conflictivas con el espacio público. Pesa a su diversidad, las intervenciones siguen patrones asociados a la solución de carencias en los diseños originales
Encuestas de Evaluación docente en Grados y Másteres: realización y propuestas de mejora de participación
Durante el curso 2016/17 se han realizado encuestas sobre todas las asignaturas y títulos impartidos en la Facultad, tanto de los Estudios de Grado como de Máster, dando continuidad a la evaluación de la calidad docente que se inició en el curso 2010/11. Estas encuestas abarcan a todos los niveles y tipos de asignaturas (prácticas, teóricas, prácticas externas) y a todo el profesorado. El cuestionario incluye además preguntas sobre los Servicios Generales (biblioteca, secretarías, aulas generales y específicas, laboratorios, cafetería, comedor, reprografía y librería), Servicios informáticos (campus virtual, web de la Facultad y redes sociales) y empleabilidad.
Los resultados se ofrecen en abierto en la página web de la Facultad, con un resumen de lo más destacado de Grados y de Másteres en los Proyectos de Innovación y Mejora de la Calidad de la Docencia (https://geografiaehistoria.ucm.es/pimcd) y más detallados en los informes de cada Grado
Galaxy clusters and groups in the ALHAMBRA Survey
We present a catalogue of 348 galaxy clusters and groups with
selected in the 2.78 ALHAMBRA Survey. The high precision of our
photometric redshifts, close to , and the wide spread of the seven
ALHAMBRA pointings ensure that this catalogue has better mass sensitivity and
is less affected by cosmic variance than comparable samples.
The detection has been carried out with the Bayesian Cluster Finder (BCF),
whose performance has been checked in ALHAMBRA-like light-cone mock catalogues.
Great care has been taken to ensure that the observable properties of the mocks
photometry accurately correspond to those of real catalogues. From our
simulations, we expect to detect galaxy clusters and groups with both
completeness and purity down to dark matter halo masses of
for . Cluster redshifts are
expected to be recovered with precision for . We also expect
to measure cluster masses with
precision down to , masses which are
smaller than those reached by similar work.
We have compared these detections with previous optical, spectroscopic and
X-rays work, finding an excellent agreement with the rates reported from the
simulations. We have also explored the overall properties of these detections
such as the presence of a colour-magnitude relation, the evolution of the
photometric blue fraction and the clustering of these sources in the different
ALHAMBRA fields. Despite the small numbers, we observe tentative evidence that,
for a fixed stellar mass, the environment is playing a crucial role at lower
redshifts (z0.5).Comment: Accepted for publication in MNRAS. Catalogues and figures available
online and under the following link:
http://bascaso.net46.net/ALHAMBRA_clusters.htm
Identification of candidate genes associated with fibromyalgia susceptibility in southern Spanish women: the al‑Ándalus project
Candidate-gene studies on fibromyalgia susceptibility often include a small number of single nucleotide
polymorphisms (SNPs), which is a limitation. Moreover, there is a paucity of evidence in Europe. Therefore, we
compared genotype frequencies of candidate SNPs in a well-characterised sample of Spanish women with fibromyalgia
and healthy non-fibromyalgia women.This work was supported by the Spanish Ministry of Economy and Competitiveness
[I+D+i DEP2010-15639, I+D+i DEP2013-40908-R to M.D.-F.;
BES-2014-067612 to F.E.-L.]; the Spanish Ministry of Education [FPU2014/02518
to M.B.-C.]; the Consejería de Turismo, Comercio y Deporte, Junta de Andalucía
[CTCD-201000019242-TRA to M.D.-F.]; Consejería de Salud, Junta de Andalucía
[PI-0520-2016 to M.D.-F.], and the University of Granada, Plan Propio de
Investigación 2016, Excellence actions: Units of Excellence; Unit of Excellence
on Exercise and Health (UCEES). This work is part of a Ph.D. Thesis conducted
in the Biomedicine Doctoral Studies of the University of Granada, Spai
Non-local heat transport in Alcator C-Mod ohmic L-mode plasmas
Non-local heat transport experiments were performed in Alcator C-Mod ohmic L-mode plasmas by inducing edge cooling with laser blow-off impurity (CaF2) injection. The non-local effect, a cooling of the edge electron temperature with a rapid rise of the central electron temperature, which contradicts the assumption of 'local' transport, was observed in low collisionality linear ohmic confinement (LOC) regime plasmas. Transport analysis shows this phenomenon can be explained either by a fast drop of the core diffusivity, or the sudden appearance of a heat pinch. In high collisionality saturated ohmic confinement (SOC) regime plasmas, the thermal transport becomes 'local': the central electron temperature drops on the energy confinement time scale in response to the edge cooling. Measurements from a high resolution imaging x-ray spectrometer show that the ion temperature has a similar behaviour as the electron temperature in response to edge cooling, and that the transition density of non-locality correlates with the rotation reversal critical density. This connection may indicate the possible connection between thermal and momentum transport, which is also linked to a transition in turbulence dominance between trapped electron modes (TEMs) and ion temperature gradient (ITG) modes. Experiments with repetitive cold pulses in one discharge were also performed to allow Fourier analysis and to provide details of cold front propagation. These modulation experiments showed in LOC plasmas that the electron thermal transport is not purely diffusive, while in SOC the electron thermal transport is more diffusive like. Linear gyrokinetic simulations suggest the turbulence outside r/a = 0.75 changes from TEM dominance in LOC plasmas to ITG mode dominance in SOC plasmas.United States. Dept. of Energy (DoE Contract No DE-FC02-99ER54512)Oak Ridge Institute for Science and Education (DOE Fusion Energy Postdoctoral Research Program
Alcator C-Mod: research in support of ITER and steps beyond
This paper presents an overview of recent highlights from research on Alcator C-Mod. Significant progress has been made across all research areas over the last two years, with particular emphasis on divertor physics and power handling, plasma–material interaction studies, edge localized mode-suppressed pedestal dynamics, core transport and turbulence, and RF heating and current drive utilizing ion cyclotron and lower hybrid tools. Specific results of particular relevance to ITER include: inner wall SOL transport studies that have led, together with results from other experiments, to the change of the detailed shape of the inner wall in ITER; runaway electron studies showing that the critical electric field required for runaway generation is much higher than predicted from collisional theory; core tungsten impurity transport studies reveal that tungsten accumulation is naturally avoided in typical C-Mod conditions.United States. Department of Energy (DE-FC02-99ER54512-CMOD)United States. Department of Energy (DE-AC02-09CH11466)United States. Department of Energy (DE-FG02-96ER-54373)United States. Department of Energy (DE-FG02-94ER54235
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