658 research outputs found

    Quadratic optimal functional quantization of stochastic processes and numerical applications

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    In this paper, we present an overview of the recent developments of functional quantization of stochastic processes, with an emphasis on the quadratic case. Functional quantization is a way to approximate a process, viewed as a Hilbert-valued random variable, using a nearest neighbour projection on a finite codebook. A special emphasis is made on the computational aspects and the numerical applications, in particular the pricing of some path-dependent European options.Comment: 41 page

    Schmallenberg virus detection in Culicoides biting midges in Spain: First laboratory evidence for highly efficient infection of Culicoides of the Obsoletus complex and Culicoides imicola

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    Since Schmallenberg disease was discovered in 2011, the disease rapidly spread across Europe. Culicoides biting midges have been implicated as putative Schmallenberg vectors in Europe. The detection of Schmallenberg virus (SBV) in field collected Culicoides was evaluated through retrospective (2011–2012) collections and captures performed in 2013. This study represents the first detection of SBV in field collected Culicoides in Spain. Infectious midges were detected at the foothills of Pyrenees, Aramunt, in the summer 2012. All the specimens infected with Schmallenberg were of the species Culicoides obsoletus s.s. confirming its putative vector status in Spain. Experimental infection on field collected Culicoides provided evidence of atypical high efficiency for SBV vector infection and transmission potential in local populations of Culicoides imicola and in Culicoides of the Obsoletus complex. However, captured individuals of C. imicola were more susceptible to SBV infection than C. obsoletus s.l. (p < .001), with an infection ratio of 0.94 and 0.63, respectively. In contrast, a Culicoides nubeculosus colony appeared to be refractory to SBV infection.info:eu-repo/semantics/acceptedVersio

    The predictive value of psychological assessment of candidates for gastric bypass: A medical chart review

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    Background and Objectives: Guidelines for bariatric surgery demand a psychological evaluation of applicants. The aim of this study was to evaluate if the presence of "psychological risk factors" predicts postoperative weight loss after gastric bypass. Methods: Medical records of obese women who underwent bariatric surgery between 2000 and 2004 were reviewed. Psychological assessment consisted of a one-hour semi-structured interview, summarized in a written report. Anthropometric assessment at baseline and 6,12,18 and 24 months after surgery included body weight, height and body mass index. Results: The mean BMI of included patients (N = 92) was 46.2 + 6,3 kg/m2 (range 38.4 - 69.7). Based on the psychological assessment, 27% (N = 25) of the patients were classified as having "psychological risk factors" and 28% (N = 26) were diagnosed with a psychiatric diagnosis, most often major depression. Two years after gastric bypass, 16% of patients with "psychological risk factors" achieved an excellent result (%EWL > 75) versus 39% of those without (p < 0.05). About 1 out of 4 patients was in postoperative psychiatric treatment, but only half of them were identified as having "psychological risk factors" at baseline. Weight loss of patients initiating a psychiatric treatment only after surgery was less than of patients who continued psychiatric treatment already initiated before surgery (55.7 + 14.8 versus 66.5 + 14.2 %EWL). Conclusions: A single semi-structured psychological interview may identify patients who are at risk for diminished postoperative weight loss; however, psychological assessment did not identify those patients who were in need of a psychiatric postoperative treatment

    Culicoides species communities associated with wild ruminant ecosystems in Spain: Tracking the way to determine potential bridge vectors for arboviruses

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    The genus Culicoides Latreille 1809 is a well-known vector for protozoa, filarial worms and, above all, numerous viruses. The Bluetongue virus (BTV) and the recently emerged Schmallenberg virus (SBV) are responsible for important infectious, non-contagious, insect-borne viral diseases found in domestic ruminants and transmitted by Culicoides spp. Both of these diseases have been detected in wild ruminants, but their role as reservoirs during the vector-free season still remains relatively unknown. In fact, we tend to ignore the possibility of wild ruminants acting as a source of disease (BTV, SBV) and permitting its reintroduction to domestic ruminants during the following vector season. In this context, a knowledge of the composition of the Culicoides species communities that inhabit areas where there are wild ruminants is of major importance as the presence of a vector species is a prerequisite for disease transmission. In this study, samplings were conducted in areas inhabited by different wild ruminant species; samples were taken in both 2009 and 2010, on a monthly basis, during the peak season for midge activity (in summer and autumn). A total of 102, 693 specimens of 40 different species of the genus Culicoides were trapped; these included major BTV and SBV vector species. The most abundant vector species were C. imicola and species of the Obsoletus group, which represented 15% and 11% of total numbers of specimens, respectively. At the local scale, the presence of major BTV and SBV vector species in areas with wild ruminants coincided with that of the nearest sentinel farms included in the Spanish Bluetongue Entomological Surveillance Programme, although their relative abundance varied. The data suggest that such species do not exhibit strong host specificity towards either domestic or wild ruminants and that they could consequently play a prominent role as bridge vectors for different pathogens between both types of ruminants. This finding would support the hypothesis that wild ruminants could act as reservoirs for such pathogens, and subsequently be involved in the reintroduction of disease to livestock on neighbouring farms

    ÂżComo podemos anallizar la competencia narrativa del alumnado en el aprendizaje de la historia?

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    The aim of this paper is to analyze the role that teachers assigned to curricular requirements, establishing the relationship between these documents and everyday practice. From the interpretation of interviews with a group of teachers, is to study the ways in which teachers used, discarded and/or reworked curriculum requirements, based on assume that they have an active role in the redefinition of such documents. The research results indicate that the new meanings and adaptations that teachers do in the written standard change according to different courtly and contextual realities

    Studies With Soft Corals – Recommendations on Sample Processing and Normalization Metrics

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    Soft corals (Octocorallia) often constitute the second most abundant macrobenthic group on many tropical and temperate reefs. However, the gelatinous and leather-like nature of their tissue and their variable hydroskeleton entails a number of problems for tissue homogenization and data normalization. An easy and fast protocol for tissue homogenization, as well as a normalization metric that can be used to perform inter-studies or inter-species comparisons, are thus needed. In this study, we tested whether the tissue sample state before processing (frozen vs. freeze-dried samples) and the media used for tissue homogenization (0.2 ÎŒm filtered seawater; FSW vs. Milli-Q water; DI) affect the quantitative measurements of tissue descriptors (chlorophyll, protein, and Symbiodinium concentrations) in the model species Heteroxenia fuscescens. Furthermore, the suitability of dry weight (DW) and ash-free dry weight (AFDW) as size-normalizing metric was investigated across different soft coral species. Our results reveal that freeze-drying the samples and homogenizing them in DI water exhibited several benefits, namely enhancing chlorophyll and protein concentrations up to 50%, saving processing time and providing a more accurate determination of DW and AFDW. Overall, this optimized tissue processing protocol offers a more reliable quantification of tissue descriptors and reduces the chance of underestimating these parameters in soft corals. Finally, since the contribution of sclerites to the total DW of the colony can highly differ between species, we demonstrate that AFDW is a reliable metric for normalizing soft coral data, particularly when inter-species comparisons are made

    A framework linking ecosystem services and human well‐being: Saltmarsh as a case study

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    1. The ecosystem services approach is based on the interdependencies between nature and human well‐being. However, while the ecosystem services aspect of this approach is well‐developed, the human well‐being aspect remains unstructured and vaguely defined. 2. An integrated conceptual framework was developed by adapting and linking the UK National Ecosystem Assessment‐Follow On framework with human well‐being domains. 3. As well as benefits, the notion of disbenefits was incorporated to recognise the potentially detrimental effects from interacting with nature. Benefits and disbenefits occur at the social–ecological interface and are classified by the seven domains of human well‐being they affect. 4. The framework is applied to saltmarsh habitat as a case study, highlighting knowledge gaps and the potential applicability and usefulness of the framework. In saltmarsh, benefits mainly accrue at larger scales with a greater impact affecting local to global individuals, while disbenefits tend to occur at a smaller scale and impact in‐situ individuals. 5. The framework provides in‐depth insight into links, trade‐offs and dichotomies between benefits and disbenefits and human well‐being, and improves accessibility to the complex research area of human well‐being. 6. This research can be a useful tool to guide environmental and health policy and management, as well as stakeholder engagement

    Effects of proton versus photon irradiation on (lymph) angiogenic, inflammatory, proliferative and anti-tumor immune responses in head and neck squamous cell carcinoma

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    International audienceThe proximity of organs at risk makes the treatment of head and neck squamous cell carcinoma (HNSCC) challenging by standard radiotherapy. The higher precision in tumor targeting of proton (P) therapy could promote it as the treatment of choice for HNSCC. Besides the physical advantage in dose deposition, few is known about the biological impact of P versus photons (X) in this setting. To investigate the comparative biological effects of P versus X radiation in HNSCC cells, we assessed the relative biological effectiveness (RBE), viability, proliferation and mRNA levels for genes involved in (lymph)angiogenesis, inflammation, proliferation and anti-tumor immunity. These parameters, particularly VEGF-C protein levels and regulations, were documented in freshly irradiated and/or long-term surviving cells receiving low/high-dose, single (SI)/multiple (MI) irradiations with P/X. The RBE was found to be 1.1 Key (lymph)angiogenesis and inflammation genes were downregulated (except for vegf-c) after P and upregulated after X irradiation in MI surviving cells, demonstrating a more favorable profile after P irradiation. Both irradiation types stimulated vegf-c promoter activity in a NF-ÎșB-dependent transcriptional regulation manner, but at a lesser extent after P, as compared to X irradiation, which correlated with mRNA and protein levels. The cells surviving to MI by P or X generated tumors with higher volume, anarchic architecture and increased density of blood vessels. Increased lymphangiogenesis and a transcriptomic analysis in favor of a more aggressive phenotype were observed in tumors generated with X-irradiated cells. Increased detection of lymphatic vessels in relapsed tumors from patients receiving X radiotherapy was consistent with these findings. This study provides new data about the biological advantage of P, as compared to X irradiation. In addition to its physical advantage in dose deposition, P irradiation may help to improve treatment approaches for HNSCC

    Delineation of Culicoides species by morphology and barcode exemplified by three new species of the subgenus Culicoides (Diptera: Ceratopogonidae) from Scandinavia

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    BACKGROUND: Culicoides biting midges (Diptera: Ceratopogonidae) cause biting nuisance to livestock and humans and are vectors of a range of pathogens of medical and veterinary importance. Despite their economic significance, the delineation and identification of species where only morphology is considered, as well as the evolutionary relationships between species within this genus remains problematic. In recent years molecular barcoding has assisted substantially in the identification of biting midges in the multiple entomological survey projects which were initiated in many European countries following the bluetongue outbreak in 2006–2009. These studies revealed potentially new species and “species-complexes” with large genetic and morphological variability. Here we use molecular barcoding, together with morphological analysis, to study subgenus Culicoides Latreille from Scandinavia with focus on three potentially new species. METHODS: Biting midges were collected at various sites in Denmark and Sweden. Culicoides specimens were described by variation of a fragment of their cytochrome c oxidase subunit 1 (COI) gene sequence and wing, palp and antennal characters. RESULTS: It is shown that three new species initially separated by DNA barcoding with mitochondrial COI can be distinguished by morphological characters. In this context a key to Scandinavian subgenus Culicoides using wing and maxillary palp characters is presented. The key is including the three new species Culicoides boyi, Culicoides selandicus and Culicoides kalix. CONCLUSION: Three new species of Culicoides biting midges were identified and could be identified by both molecular and morphological differences. Evaluation of differences between and within taxa of biting midges using COI barcode yielded a rough estimate of species delineation; interspecies differences across Culicoides subgenera approaches 20%, whereas intraspecies differences are below 4% and in most cases below 1%. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13071-015-0750-4) contains supplementary material, which is available to authorized users

    Rift Valley fever virus and European mosquitoes vector competence of Culex pipiens and Stegomyia albopicta (= Aedes albopictus)

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    Rift Valley fever (RVF) is a mosquito-borne disease caused by the Rift Valley fever virus (RVFV). Rift Valley fever affects a large number of species, including human, and has severe impact on public health and the economy, especially in African countries. The present study examined the vector competence of three different European mosquito species, Culex pipiens (Linnaeus, 1758) form molestus (Diptera Culicidae), Culex pipiens hybrid form and Stegomyia albopicta (= Aedes albopictus) (Skuse, 1894) (Diptera Culicidae). Mosquitoes were artificially fed with blood containing RVFV. Infection, disseminated infection and transmission efficiency were evaluated. This is the first study to assess the transmission efficiency of European mosquito species using a virulent RVFV strain. The virus disseminated in Cx. pipiens hybrid form and in S. albopicta. Moreover, infectious viral particles were isolated from saliva of both species, showing their RVFV transmission capacity. The presence of competent Cx. pipiens and S. albopicta in Spain indicates that an autochthonous outbreak of RVF may occur if the virus is introduced. These findings provide information that will help health authorities to set up efficient entomological surveillance and RVFV vector control programmes. © 2017 The Authors. Medical and Veterinary Entomology published by John Wiley & Sons Ltd on behalf of Royal Entomological Society
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