159 research outputs found

    What drives corporate default risk premia? Evidence from the CDS market

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    This paper studies the evolution of the default risk premia for European firms during the years surrounding the recent credit crisis. We employ the information embedded in Credit Default Swaps (CDS) and Moody’s KMV EDF default probabilities to analyze the common factors driving this risk premia. The risk premium is characterized in several directions: Firstly, we perform a panel data analysis to capture the relationship between CDS spreads and actual default probabilities. Secondly, we employ the intensity framework of Jarrow et al. (2005) in order to measure the theoretical effect of risk premium on expected bond returns. Thirdly, we carry out a dynamic panel data to identify the macroeconomic sources of risk premium. Finally, a vector autoregressive model analyzes which proportion of the co-movement is attributable to financial or macro variables. Our estimations report coefficients for risk premium substantially higher than previously referred for US firms and a time varying behavior. A dominant factor explains around 60% of the common movements in risk premia. Additionally, empirical evidence suggests a public-to-private risk transfer between the sovereign CDS spreads and corporate risk premia

    Assessment and counseling to get the best efficiency and effectiveness of the assistive technology (MATCH): study protocol

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    Clinical Trials ID: NCT04723784[Abstract] Aims: To determine the psychosocial impact of assistive technology(AT) based on robotics and artificial intelligence in the life of people with disabilities. Background: The best match between any person with disabilities and its AT only can be gotten through a complete assessment and monitoring of his/her needs, abilities, priorities, difficulties and limitations. Without this analysis, it's possible that the device won't meet the individual's expectations. Therefore, it is important that any project focused on the development of innovating AT for people with disabilities includes the perspective of outcome measures as an important phase of the research. In this sense, the integration of the assessment, implementation process and outcome measures is crucial to guarantee the transferability for the project findings and to get the perspective from the final user. Methods: Pilot study, with prospective, longitudinal and analytical cohort. The study lasts from July 2020 until April 2023. The sample is formed by people with disabilities, ages from 2-21, that will participate from the first stage of the process (initial assessment of their abilities and needs) to the final application of outcome measures instruments (with a complete implication during the test of technology). Discussion: Only with the active participation of the person is possible to carry out a user-centered approach. This fact will allow us to define and generate technological solutions that really adjust to the expectations, needs and priorities of the people with disabilities, avoiding the AT from being abandoned, with the consequent health and social spending.Ministerio de Ciencia e Innovación (España); PID2019-104323RB-C31Ministerio de Ciencia e Innovación (España); PID2019-104323RB-C32Ministerio de Ciencia e Innovación (España); PID2019-104323RB-C33Ministerio de Ciencia e Innovación (España); PID2019-104323RB-C3

    Have State Renewable Portfolio Standards Really Worked? Synthesizing Past Policy Assessments to Build an Integrated Econometric Analysis of RPS effectiveness in the U.S.

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    Renewable portfolio standards (RPS) are the most popular U.S. state-level policies for promoting deployment of renewable electricity (RES-E). While several econometric studies have estimated the effect of RPS on in-state RES-E deployment, results are contradictory. We reconcile these studies and move toward a definitive answer to the question of RPS effectiveness. We conduct an analysis using time series cross sectional regressions - including the most nuanced controls for policy design features to date - and nonparametric matching analysis. We find that higher RPS stringency does not necessarily drive more RES-E deployment. We examine several RPS design features and market characteristics (including REC unbundling, RPS in neighboring states, out-of-state renewable energy purchases) that may explain the gap between effective and ineffective policies. We also investigate other RES-E policies and technology-specific effects. Ultimately, we show that RPS effectiveness is largely explained by a combination of policy design, market context, and inter-state trading effects

    Methods to study splicing from high-throughput RNA Sequencing data

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    The development of novel high-throughput sequencing (HTS) methods for RNA (RNA-Seq) has provided a very powerful mean to study splicing under multiple conditions at unprecedented depth. However, the complexity of the information to be analyzed has turned this into a challenging task. In the last few years, a plethora of tools have been developed, allowing researchers to process RNA-Seq data to study the expression of isoforms and splicing events, and their relative changes under different conditions. We provide an overview of the methods available to study splicing from short RNA-Seq data. We group the methods according to the different questions they address: 1) Assignment of the sequencing reads to their likely gene of origin. This is addressed by methods that map reads to the genome and/or to the available gene annotations. 2) Recovering the sequence of splicing events and isoforms. This is addressed by transcript reconstruction and de novo assembly methods. 3) Quantification of events and isoforms. Either after reconstructing transcripts or using an annotation, many methods estimate the expression level or the relative usage of isoforms and/or events. 4) Providing an isoform or event view of differential splicing or expression. These include methods that compare relative event/isoform abundance or isoform expression across two or more conditions. 5) Visualizing splicing regulation. Various tools facilitate the visualization of the RNA-Seq data in the context of alternative splicing. In this review, we do not describe the specific mathematical models behind each method. Our aim is rather to provide an overview that could serve as an entry point for users who need to decide on a suitable tool for a specific analysis. We also attempt to propose a classification of the tools according to the operations they do, to facilitate the comparison and choice of methods.Comment: 31 pages, 1 figure, 9 tables. Small corrections adde

    Pregnancy-associated osteoporosis. Presentation of 5 cases and long term monitoring

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    Fundamento: La osteoporosis del embarazo (OPE) es una entidad claramente descrita y relativamente frecuente, aunque existen pocos estudios que hayan realizado un seguimiento a largo plazo de la enfermedad. Material y métodos: Se estudió a 5 mujeres afectas de osteoporosis del embarazo a las que se les hizo un seguimiento a largo plazo, entre 4 y 16 años. A todas las pacientes se les realizó un cuestionario sobre estilos de vida y factores de riesgo, una exploración física completa, así como una densitometría tras el embarazo y posteriormente cada año mientras duró el seguimiento. Al finalizar éste, se les realizó una radiografía lateral de columna dorsal y lumbar. Resultados: En 3 casos, se produjo una fractura espontánea como primera manifestación de la OPE, mientras que en 2 casos se observó un valor densitométrico muy bajo sin fracturas en el postparto inmediato. Todas las pacientes recibieron un suplemento de calcio y vitamina D, y en 3 casos se indicó un bifosfonato (risedronato). No se observó ninguna nueva fractura en ningún caso a lo largo del periodo de seguimiento. La densidad mineral ósea (DMO) aumentó en la columna lumbar en todas las pacientes, pero en una de ellas se observó un descenso en la medición de cadera, tanto en cuello femoral como en el total de cadera. Ninguna paciente volvió a quedarse embarazada en el periodo de estudio. Conclusiones: Aunque ninguna de las 5 pacientes con OPE estudiadas a largo plazo sufrió una nueva fractura, y en todas se observó un incremento en la densidad mineral ósea de la columna lumbar, lo que nos hace pensar en una recuperación de la DMO con el tiempo, en 1 caso se produjo un descenso considerable de la densidad mineral ósea en fémur proximal, por lo que creemos que es recomendable realizar seguimientos a largo plazo a estas pacientes.Background: Pregnancy-associated osteoporosis (PAO) is a clearly described and relatively frequent entity, although there are few studies which have carried out long term monitoring of the disease. Material and methods: 5 women affected by osteoporosis who were monitored over the long term, between 4 and 16 years. In all the patients a questionnaire on lifestyle and risk factors was completed and a physical examination carried out, as well as densitometry after the pregnancy and subsequently every year during the follow up period. At the end of this period, a lateral X-ray of the dorsal and lumbar spine was performed. Results: In 3 cases there was a spontaneous fracture as the first manifestation of PAO, while in 2 cases a very low densitometric value was observed, without fractures, in the immediate postpartum period. All the patients received calcium and vitamin D supplements, and in 3 cases a biphosphonate (risedronate) was indicated. No new fractures were observed in any of the cases over the follow up period. The bone mineral density (BMD) increased in the lumbar spine in all the patients, but in one a decreased measu rement was observed in the hip, both in the femoral neck and the total hip. None of the patients beca me pregnant again in the period of the study. Conclusions: While none of the patients with PAO studied over the long term suffered a new fracture, and in all an increase in the bone mineral density in the lumbar spine was observed, which makes us think that there is a recovery of DMO over time, in one case there was a considerable decrease in bone mineral density in the proximal femur, for which reason we believe that it is advisable to carry out long term monitoring of these patients

    Estimation of alternative splicing isoform frequencies from RNA-Seq data

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    <p>Abstract</p> <p>Background</p> <p>Massively parallel whole transcriptome sequencing, commonly referred as RNA-Seq, is quickly becoming the technology of choice for gene expression profiling. However, due to the short read length delivered by current sequencing technologies, estimation of expression levels for alternative splicing gene isoforms remains challenging.</p> <p>Results</p> <p>In this paper we present a novel expectation-maximization algorithm for inference of isoform- and gene-specific expression levels from RNA-Seq data. Our algorithm, referred to as IsoEM, is based on disambiguating information provided by the distribution of insert sizes generated during sequencing library preparation, and takes advantage of base quality scores, strand and read pairing information when available. The open source Java implementation of IsoEM is freely available at <url>http://dna.engr.uconn.edu/software/IsoEM/</url>.</p> <p>Conclusions</p> <p>Empirical experiments on both synthetic and real RNA-Seq datasets show that IsoEM has scalable running time and outperforms existing methods of isoform and gene expression level estimation. Simulation experiments confirm previous findings that, for a fixed sequencing cost, using reads longer than 25-36 bases does not necessarily lead to better accuracy for estimating expression levels of annotated isoforms and genes.</p

    Genetic Tests for Ecological and Allopatric Speciation in Anoles on an Island Archipelago

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    From Darwin's study of the Galapagos and Wallace's study of Indonesia, islands have played an important role in evolutionary investigations, and radiations within archipelagos are readily interpreted as supporting the conventional view of allopatric speciation. Even during the ongoing paradigm shift towards other modes of speciation, island radiations, such as the Lesser Antillean anoles, are thought to exemplify this process. Geological and molecular phylogenetic evidence show that, in this archipelago, Martinique anoles provide several examples of secondary contact of island species. Four precursor island species, with up to 8 mybp divergence, met when their islands coalesced to form the current island of Martinique. Moreover, adjacent anole populations also show marked adaptation to distinct habitat zonation, allowing both allopatric and ecological speciation to be tested in this system. We take advantage of this opportunity of replicated island coalescence and independent ecological adaptation to carry out an extensive population genetic study of hypervariable neutral nuclear markers to show that even after these very substantial periods of spatial isolation these putative allospecies show less reproductive isolation than conspecific populations in adjacent habitats in all three cases of subsequent island coalescence. The degree of genetic interchange shows that while there is always a significant genetic signature of past allopatry, and this may be quite strong if the selection regime allows, there is no case of complete allopatric speciation, in spite of the strong primae facie case for it. Importantly there is greater genetic isolation across the xeric/rainforest ecotone than is associated with any secondary contact. This rejects the development of reproductive isolation in allopatric divergence, but supports the potential for ecological speciation, even though full speciation has not been achieved in this case. It also explains the paucity of anole species in the Lesser Antilles compared to the Greater Antilles

    The first transcriptome of Italian wall lizard, a new tool to infer about the Island Syndrome

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    Some insular lizards show a high degree of differentiation from their conspecific mainland populations, like Licosa island lizards, which are described as affected by Reversed Island Syndrome (RIS). In previous works, we demonstrated that some traits of RIS, as melanization, depend on a differential expression of gene encoding melanocortin receptors. To better understand the basis of syndrome, and providing raw data for future investigations, we generate the first de novo transcriptome of the Italian wall lizard. Comparing mainland and island transcriptomes, we link differences in life-traits to differential gene expression. Our results, taking together testis and brain sequences, generated 275,310 and 269,885 transcripts, 18,434 and 21,606 proteins in Gene Ontology annotation, for mainland and island respectively. Variant calling analysis identified about the same number of SNPs in island and mainland population. Instead, through a differential gene expression analysis we found some putative genes involved in syndrome more expressed in insular samples like Major Histocompatibility Complex class I, Immunoglobulins, Melanocortin 4 receptor, Neuropeptide Y and Proliferating Cell Nuclear Antigen

    De Novo Transcriptome Sequencing in Anopheles funestus Using Illumina RNA-Seq Technology

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    BACKGROUND: Anopheles funestus is one of the primary vectors of human malaria, which causes a million deaths each year in sub-Saharan Africa. Few scientific resources are available to facilitate studies of this mosquito species and relatively little is known about its basic biology and evolution, making development and implementation of novel disease control efforts more difficult. The An. funestus genome has not been sequenced, so in order to facilitate genome-scale experimental biology, we have sequenced the adult female transcriptome of An. funestus from a newly founded colony in Burkina Faso, West Africa, using the Illumina GAIIx next generation sequencing platform. METHODOLOGY/PRINCIPAL FINDINGS: We assembled short Illumina reads de novo using a novel approach involving iterative de novo assemblies and "target-based" contig clustering. We then selected a conservative set of 15,527 contigs through comparisons to four Dipteran transcriptomes as well as multiple functional and conserved protein domain databases. Comparison to the Anopheles gambiae immune system identified 339 contigs as putative immune genes, thus identifying a large portion of the immune system that can form the basis for subsequent studies of this important malaria vector. We identified 5,434 1:1 orthologues between An. funestus and An. gambiae and found that among these 1:1 orthologues, the protein sequence of those with putative immune function were significantly more diverged than the transcriptome as a whole. Short read alignments to the contig set revealed almost 367,000 genetic polymorphisms segregating in the An. funestus colony and demonstrated the utility of the assembled transcriptome for use in RNA-seq based measurements of gene expression. CONCLUSIONS/SIGNIFICANCE: We developed a pipeline that makes de novo transcriptome sequencing possible in virtually any organism at a very reasonable cost ($6,300 in sequencing costs in our case). We anticipate that our approach could be used to develop genomic resources in a diversity of systems for which full genome sequence is currently unavailable. Our An. funestus contig set and analytical results provide a valuable resource for future studies in this non-model, but epidemiologically critical, vector insect
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