10,966 research outputs found

    Conservation genetics of Iberian raptors

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    Genética de la conservación de rapaces ibéricas En este artículo se da una visión global de lo que es la genética de la conservación y cuáles son las acciones de manejo en la naturaleza que pueden beneficiarse de los estudios genéticos. Se presentan en primer lugar los factores genéticos de riesgo para la supervivencia de las especies y cuáles son las consecuencias de la pérdida de diversidad genética y de la depresión tanto por endogamia como por exogamia. Se explica el uso de las herramientas genéticas en la delimitación de las unidades de conservación. Tras ello se explica cuáles son las aplicaciones más comunes de la genética de la conservación en el manejo de poblaciones silvestres. En una segunda parte del artículo se hace una revisión de los estudios en genética de la conservación llevados a cabo en rapaces ibéricas. Se explican varios estudios llevados a cabo sobre el águila imperial ibérica, el quebrantahuesos, el buitre negro y el milano real usando marcadores en microsatélites autosomales y secuencias de ADN mitocondrial (mtDNA). Se describen estudios sobre el cernícalo primilla y el alimoche que han utilizado adicionalmente marcadores en el complejo de histocompatibilidad mayor (MHC) con el propósito de incorporar el estudio de variación no neutral. Para cada una de las especies se explica cómo estos estudios se pueden aplicar y/o se aplican en las estrategias de conservación de dichas especies en la naturaleza. Palabras clave: Genética de la conservación, Genómica de la conservación, Marcadores moleculares, Rapaces ibéricas, Manejo de poblaciones amenazadas.In this paper I provide an overview of conservation genetics and describe the management actions in the wild that can benefit from conservation genetic studies. I describe the genetic factors of risk for the survival of wild species, the consequences of loss of genetic diversity, inbreeding and outbreeding depression, and the use of genetic tools to delimitate units of conservation. Then I introduce the most common applications of conservation genetics in the management of wild populations. In a second part of the paper I review the conservation genetic studies carried on the Iberian raptors. I introduce several studies on the Spanish imperial eagle, the bearded vulture, the black vulture and the red kite that were carried out using autosomal microsatellite markers and mitochondrial DNA (mtDNA) sequencing. I describe studies on the lesser kestrel and Egyptian vulture that additionally applied major histocompatibility complex (MHC) markers, with the purpose of incorporating the study of non–neutral variation. For every species I explain how these studies can be and/or are applied in the strategy of conservation in the wild. Key words: Conservation genetics, Conservation genomics, Molecular markers, Iberian raptors, Management of threatened populations.Genética de la conservación de rapaces ibéricas En este artículo se da una visión global de lo que es la genética de la conservación y cuáles son las acciones de manejo en la naturaleza que pueden beneficiarse de los estudios genéticos. Se presentan en primer lugar los factores genéticos de riesgo para la supervivencia de las especies y cuáles son las consecuencias de la pérdida de diversidad genética y de la depresión tanto por endogamia como por exogamia. Se explica el uso de las herramientas genéticas en la delimitación de las unidades de conservación. Tras ello se explica cuáles son las aplicaciones más comunes de la genética de la conservación en el manejo de poblaciones silvestres. En una segunda parte del artículo se hace una revisión de los estudios en genética de la conservación llevados a cabo en rapaces ibéricas. Se explican varios estudios llevados a cabo sobre el águila imperial ibérica, el quebrantahuesos, el buitre negro y el milano real usando marcadores en microsatélites autosomales y secuencias de ADN mitocondrial (mtDNA). Se describen estudios sobre el cernícalo primilla y el alimoche que han utilizado adicionalmente marcadores en el complejo de histocompatibilidad mayor (MHC) con el propósito de incorporar el estudio de variación no neutral. Para cada una de las especies se explica cómo estos estudios se pueden aplicar y/o se aplican en las estrategias de conservación de dichas especies en la naturaleza. Palabras clave: Genética de la conservación, Genómica de la conservación, Marcadores moleculares, Rapaces ibéricas, Manejo de poblaciones amenazadas

    Novel efficient genome-wide SNP panels for the conservation of the highly endangered Iberian lynx

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    Background: The Iberian lynx (Lynx pardinus) has been acknowledged as the most endangered felid species in the world. An intense contraction and fragmentation during the twentieth century left less than 100 individuals split in two isolated and genetically eroded populations by 2002. Genetic monitoring and management so far have been based on 36 STRs, but their limited variability and the more complex situation of current populations demand more efficient molecular markers. The recent characterization of the Iberian lynx genome identified more than 1.6 million SNPs, of which 1536 were selected and genotyped in an extended Iberian lynx sample. Methods: We validated 1492 SNPs and analysed their heterozygosity, Hardy-Weinberg equilibrium, and linkage disequilibrium. We then selected a panel of 343 minimally linked autosomal SNPs from which we extracted subsets optimized for four different typical tasks in conservation applications: individual identification, parentage assignment, relatedness estimation, and admixture classification, and compared their power to currently used STR panels. Results: We ascribed 21 SNPs to chromosome X based on their segregation patterns, and identified one additional marker that showed significant differentiation between sexes. For all applications considered, panels of autosomal SNPs showed higher power than the currently used STR set with only a very modest increase in the number of markers. Conclusions: These novel panels of highly informative genome-wide SNPs provide more powerful, efficient, and flexible tools for the genetic management and non-invasive monitoring of Iberian lynx populations. This example highlights an important outcome of whole-genome studies in genetically threatened species

    Integrable models and degenerate horizons in two-dimensional gravity

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    We analyse an integrable model of two-dimensional gravity which can be reduced to a pair of Liouville fields in conformal gauge. Its general solution represents a pair of ``mirror'' black holes with the same temperature. The ground state is a degenerate constant dilaton configuration similar to the Nariai solution of the Schwarzschild-de Sitter case. The existence of ϕ=const.\phi=const. solutions and their relation with the solution given by the 2D Birkhoff's theorem is then investigated in a more general context. We also point out some interesting features of the semiclassical theory of our model and the similarity with the behaviour of AdS2_2 black holes.Comment: Latex, 16 pages, 1 figur

    Intermittent reconnection and plasmoids in UV bursts in the low solar atmosphere

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    Magnetic reconnection is thought to drive a wide variety of dynamic phenomena in the solar atmosphere. Yet the detailed physical mechanisms driving reconnection are difficult to discern in the remote sensing observations that are used to study the solar atmosphere. In this paper we exploit the high-resolution instruments Interface Region Imaging Spectrograph (IRIS) and the new CHROMIS Fabry-Perot instrument at the Swedish 1-m Solar Telescope (SST) to identify the intermittency of magnetic reconnection and its association with the formation of plasmoids in so-called UV bursts in the low solar atmosphere. The Si IV 1403A UV burst spectra from the transition region show evidence of highly broadened line profiles with often non-Gaussian and triangular shapes, in addition to signatures of bidirectional flows. Such profiles had previously been linked, in idealized numerical simulations, to magnetic reconnection driven by the plasmoid instability. Simultaneous CHROMIS images in the chromospheric Ca II K 3934A line now provide compelling evidence for the presence of plasmoids, by revealing highly dynamic and rapidly moving brightenings that are smaller than 0.2 arcsec and that evolve on timescales of order seconds. Our interpretation of the observations is supported by detailed comparisons with synthetic observables from advanced numerical simulations of magnetic reconnection and associated plasmoids in the chromosphere. Our results highlight how subarcsecond imaging spectroscopy sensitive to a wide range of temperatures combined with advanced numerical simulations that are realistic enough to compare with observations can directly reveal the small-scale physical processes that drive the wide range of phenomena in the solar atmosphere.Comment: Accepted for publication in Astrophysical Journal Letters. Movies are available at http://folk.uio.no/rouppe/plasmoids_chromis

    Análisis funcional de efectores candidatos de Podosphaera xanthii

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    Los oídios son patógenos biotrofos obligados que requieren células vivas para su desarrollo, por lo que deben eludir o inhibir las respuestas de defensa de la planta mediante la secreción de efectores para completar su ciclo de vida. El haustorio, estructura del hongo especializada en la toma de nutrientes, es también la vía de intercambio de factores con las células huésped. Hasta la fecha, son muy numerosos los efectores identificados en diversos hongos fitopatógenos, sin embargo, los efectores de los oídios están poco caracterizados todavía. En este trabajo hemos desarrollado un método para la identificación y el análisis de efectores candidatos de Podosphaera xanthii (ECP), el principal agente causal del oídio de las cucurbitáceas, mediante silenciamiento génico inducido por hospedador (HIGS) y la sobrexpresión de estos efectores en cotiledones de melón, utilizando para ello Agrobacterium tumefaciens. El silenciamiento de algunos de los ECP analizados provocó la acumulación en las células de la planta de compuestos relacionados con las respuestas de defensa como peróxido de hidrógeno (H2O2) y calosa, lo que sugiere un importante papel en el establecimiento de la infección. En concreto, ECPEc2 parece interferir específicamente con la formación de la papila, primera barrera de defensa de la planta que impide o ralentiza la penetración de la célula vegetal. En el caso de ECP5191, su silenciamiento se traduce un aumento del número de células que acumulaban H2O2 y calosa, así como una disminución en el número de puntos de penetración del hongo, observándose todo lo contrario cuando se sobrexpresa dicho efector. Además, la fusión traduccional CSEP5191-GFP ha permitido localizar este efector en los puntos de penetración y vesículas del haustorio del hongo.Este trabajo ha sido financiado por ayudas del Plan Nacional de I+D+I del anterior Ministerio de Ciencia e Innovación (AGL2010-21848-CO2-01), cofinanciado con fondos FEDER (UE)y una ayuda del Plan Propio de Investigación de la Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Efficacy and sex-specific outcomes after six episodes of percutaneous tibial nerve stimulation treatment on overactive bladder syndrome symptoms

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    ObjectiveThis study aimed to investigate the efficacy of six episodes of percutaneous tibial nerve stimulation (PTNS) treatment for overactive bladder (OAB) symptoms in men and women and to determine the duration of the effects over a 6-month period.MethodsWomen and men with OAB symptoms participated in the study, which was conducted in accordance with an approved ethical protocol (ISRCTN15733799). Patients underwent six 30-min PTNS sessions, twice per week. The symptoms of OAB were assessed using a voiding diary, the short form of the Overactive Bladder Symptom Score questionnaire (OAB-q SF), and the Patient Perception of Bladder Condition (PPBC), which were self-completed by patients before and after treatment (24 h and at 1, 3, and 6 months). The outcome data were compared for sex and time points using two-way ANOVA for repeated measures.ResultsPTNS treatment significantly improved the OAB symptoms and quality of life in men and women. PTNS increased the voided volume (p < 0.05) and decreased the frequency of voiding, nocturia, and urgency at 24 h and up to 6 months (p < 0.001). The OABq-SF and PPBC scores were significantly decreased after PTNS (p < 0.001). Urgency was greater in men than in women. The duration of PTNS clinical success on frequency and the perception of improvement in quality of life were greater in women than in men.ConclusionThe clinical effects of six sessions of PTNS strongly suggest its potential for shortening, from the standard 12 sessions, to effectively alleviate symptoms of OAB. This therapeutic procedure would reduce both the time and economic costs of OAB treatment

    The postulates of gravitational thermodynamics

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    The general principles and logical structure of a thermodynamic formalism that incorporates strongly self-gravitating systems are presented. This framework generalizes and simplifies the formulation of thermodynamics developed by Callen. The definition of extensive variables, the homogeneity properties of intensive parameters, and the fundamental problem of gravitational thermodynamics are discussed in detail. In particular, extensive parameters include quasilocal quantities and are naturally incorporated into a set of basic general postulates for thermodynamics. These include additivity of entropies (Massieu functions) and the generalized second law. Fundamental equations are no longer homogeneous first-order functions of their extensive variables. It is shown that the postulates lead to a formal resolution of the fundamental problem despite non-additivity of extensive parameters and thermodynamic potentials. Therefore, all the results of (gravitational) thermodynamics are an outgrowth of these postulates. The origin and nature of the differences with ordinary thermodynamics are analyzed. Consequences of the formalism include the (spatially) inhomogeneous character of thermodynamic equilibrium states, a reformulation of the Euler equation, and the absence of a Gibbs-Duhem relation.Comment: 28 pages, Revtex, no figures. An important sentence and several minor corrections included. To appear in Physical Review

    A vision about lifelong learning and its barriers

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    Around 25 years ago, some researchers argued for moving towards innovative learning models characterized by being more personalized and where the students would have a more active role in deciding what to learn, when to learn and how to learn. Nowadays, there is a need for a flexible, efficient, universal and lifelong education. Lifelong learning is fully integrated into our society and, from the student point of view, it is very different from regular learning. Among these differences there is the maturity of students, the fact that the domains of interest are much broader, the way how learning occurs at different depths, the fact that the topics to study may be related both to work, family and leisure, and that students have little availability due to their necessity to conciliate home, work, leisure and learning. Lifelong learning requires personalized models that adapt to students'' needs and constraints, but lifelong learners keep suffering from models that are neither adapted to their necessities, nor to the needs of society. This paper reflects on the actual situation of lifelong learning, analyses some of the relevant literature and discusses the challenges to conceptualize, from a transdisciplinary point of view, innovative e-learning models that promote self-determination of students

    p53 and bcl-2 expression in high-grade B-cell lymphomas: correlation with survival time.

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    B-cell high-grade lymphomas are heterogeneous in terms of histology, clinical presentation, treatment response and prognosis. As bcl-2 and p53 gene deregulations are frequently involved in several types of lymphoid malignancies, we aimed our investigation at the study of the relation between bcl-2 and p53 expression and survival probability in a group of 119 patients with B-cell high-grade lymphoma. These were obtained from the Virgen de la Salud Hospital, Toledo, Spain (73 cases), John Radcliffe Hospital, Oxford, UK (31 cases), and the Istituto Nazionale dei Tumori, Milan, Italy (15 cases). The relation between bcl-2 protein expression and survival was small, depending on the primary localisation of the tumour (in lymph node of mucosae), and lacked a significant correlation with overall survival. In contrast with this, p53 expression was related to survival probability in our series, this relation being both significant and independent of histological diagnosis. p53-positive patients showed a sudden decrease in life expectancy in the first months after diagnosis. Multivariant regression analysis confirmed that the only parameters significantly related with survival were extranodal origin, which is associated with a better prognosis, and p53 expression, which indicates a poor prognosis. Simultaneous expression of bcl-2 and p53 was associated with a poorer prognosis than p53 alone. This is particularly significant for large B-cell lymphomas presenting in lymph nodes. The cumulative poor effect of both p53 and bcl-2 in large B-cell lymphomas, which is more significant in nodal tumours, could confirm the existence of a multistep genetic deregulation in non-Hodgkin's lymphoma. This indicates that the genetic mechanisms controlling apoptosis and their disregulation are critical steps in the progression of lymphomas
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