2,034 research outputs found

    Tunable Sensitivity in Long Period Fiber Gratings During Mode Transition With Low Refractive Index Intermediate Layer

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    Double-clad fibers where the second cladding has a lower refractive index than the first cladding, prove to be ideal structures for potentiating and tuning the sensitivity in long-period fiber gratings (LPFGs) operating in mode transition. When a thin film is deposited on the optical fiber, the second cladding performs acts as a barrier that initially prevents the transition to guidance in the thin film of one of the modes guided in the first cladding. Finally, the transition to guidance occurs with a sensitivity increase, in analogy to the tunnel effect observed in semiconductors. This improvement has been demonstrated both as a function of the thin film thickness and the surrounding medium refractive index, with enhancement factors of 4 and 2, respectively. This idea reinforces the performance of LPFGs, adding a new degree of freedom to the mode transition and the dispersion turning point phenom- ena. Moreover, the control of the variation of the effective index of cladding modes could be applied in other structures, such as tilted-fiber gratings or evanescent wave sensors

    Diagnóstico antenatal de la madurez pulmonar fetal en embarazos normales y patológicos

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    Hemos realizado un estudio de madurez fetal, en muestras de líquido amniótico obtenido en 112 mujeres en las que el parto se produjo antes de transcurridos 7 días tras la amniocentesis. Comparamos el test de Clements, el estudio de células naranaja, la DO a 650 y 400 NM y la determinación de creatinina, con el cociente lecitina/ esfingomielina. El test de Clements y la determinación de DO presentan una buena correlación con el cociente L/E

    An approach to age and growth of south Atlantic swordfish (Xiphias gladius) stock

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    A first growth function was estimated for the South Atlantic swordfish stock. A total of 406 anal fins were collected from 2006 to 2013. Fins were classified into three types and the most common, type A, was selected. Biometric relationships among several ray section measurements and lower jaw fork length were analysed. A detailed methodological description for swordfish age interpretation has been developed. Inconclusive results have been obtained when indirect validation test, as edge type and marginal increment ratio analysis, were applied. Mean size at age and growth parameters were estimated using the Standard Von Bertalanffy growth model (VBGM) (L∞= 358.7, k= 0.092, t0= -1.929), which showed the best fit in comparison with other VBGMs

    Issues related to the MEDITS reference list of species

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    The MEDITS survey programme started in 1994 and adopted the basic protocols by the four first partners, just before the first survey. These protocols included the design of the survey, the sampling gear, the information collected, and the management of the data as far as the production of common standardized analyses of the data (Bertrand et al., 2002). The last updating of protocols has been done in 2007 (MEDITS, 2007). According to it, for each species the total weight and number of individuals is recorded. For a reference list of 38 species of fish, crustaceans and cephalopods, the length frequency by sex must be reported, as well as the maturity stage of the gonads. However, two different things should be taken into account. On one hand, for most works performed using MEDITS data (including assessments), the length frequency distributions are used, without taking into account the sex. On the other hand, the period of the surveys is not always coincident with the spawning season for all the species in the MEDITS reference list. This document attempts to be a practical exercise in relation to these topics, using both surveys and commercial data, and gives some proposals to the reference list of specie

    Interaction between Calpain 5, Peroxisome proliferator-activated receptor-gamma and Peroxisome proliferator-activated receptor-delta genes: a polygenic approach to obesity

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    <p>Abstract</p> <p>Context</p> <p>Obesity is a multifactorial disorder, that is, a disease determined by the combined effect of genes and environment. In this context, polygenic approaches are needed.</p> <p>Objective</p> <p>To investigate the possibility of the existence of a crosstalk between the <it>CALPAIN 10 </it>homologue <it>CALPAIN 5 </it>and nuclear receptors of the peroxisome proliferator-activated receptors family.</p> <p>Design</p> <p>Cross-sectional, genetic association study and gene-gene interaction analysis.</p> <p>Subjects</p> <p>The study sample comprise 1953 individuals, 725 obese (defined as body mass index ≥ 30) and 1228 non obese subjects.</p> <p>Results</p> <p>In the monogenic analysis, only the peroxisome proliferator-activated receptor delta (<it>PPARD</it>) gene was associated with obesity (OR = 1.43 [1.04–1.97], p = 0.027). In addition, we have found a significant interaction between <it>CAPN5 </it>and <it>PPARD </it>genes (p = 0.038) that reduces the risk for obesity in a 55%.</p> <p>Conclusion</p> <p>Our results suggest that <it>CAPN5 </it>and <it>PPARD </it>gene products may also interact in vivo.</p

    A colorectal cancer susceptibility new variant at 4q26 in the Spanish population identified by genome-wide association analysis

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    This work was partially supported by the CENIT program from the Centro Tecnológico Industrial (CEN-20091016), grants from the Spanish Institute of Health Carlos III (ADE10/00026, PI09/02444, PI12/00511, Acción Transversal de Cáncer) grants from the Fondo de Investigacion Sanitaria/FEDER (08/1276, 08/0024, PS09/02368, 11/00219, 11/00681), and by COST office through COST action BM1206. SCB is supported by contracts from the Fondo de Investigación Sanitaria (CP 03-0070). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Centro Tecnológico IndustrialInstituto de Salud Carlos IIIFondo de Investigación Sanitaria / FEDE

    Asociaciones de moluscos de fondos sedimentarios circalitorales y batiales del norte del mar de Alborán

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    Molluscan assemblages from shelf and slope soft bottoms of the Alboran Sea have been sampled with a beam trawl during 2014 and 2015 MEDITS expeditions. A total of 134 spp. of molluscs (shell size > 3 mm) were identified, being gastropods the most diverse and dominant group. Four main depth related assemblages were detected in multivariate analyses and characterized by (1) Turritella communis, Chamelea striatula and Nucula sulcata for the inner shelf, (2) Timoclea ovata, Clelandella miliaris and Neopycnodonte cochlear for the outer shelf, (3) Nassarius ovoideus, Calumbonella suturale and N. sulcata for the upper slope and (4) Abra longicallus, Euspira fusca and Aporrhais serresianus for the middle slope. Species richness and abundance decreased with depth, unlike evenness and Shannon-Wiener diversity which displayed an opposite pattern. A higher spatial variability was detected for the shelf, indicating that more assemblages may occur at this level and further sampling is needed for covering all sedimentary habitat types of the Alboran Sea.Versión del edito

    Is ultra-violet radiation the main force shaping molecular evolution of varicella-zoster virus?

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    <p>Abstract</p> <p>Background</p> <p>Varicella (chickenpox) exhibits a characteristic epidemiological pattern which is associated with climate. In general, primary infections in tropical regions are comparatively less frequent among children than in temperate regions. This peculiarity regarding varicella-zoster virus (VZV) infection among certain age groups in tropical regions results in increased susceptibility during adulthood in these regions. Moreover, this disease shows a cyclic behavior in which the number of cases increases significantly during winter and spring. This observation further supports the participation of environmental factors in global epidemiology of chickenpox. However, the underlying mechanisms responsible for this distinctive disease behavior are not understood completely. In a recent publication, Philip S. Rice has put forward an interesting hypothesis suggesting that ultra-violet (UV) radiation is the major environmental factor driving the molecular evolution of VZV.</p> <p>Discussion</p> <p>While we welcomed the attempt to explain the mechanisms controlling VZV transmission and distribution, we argue that Rice's hypothesis takes lightly the circulation of the so called "temperate VZV genotypes" in tropical regions and, to certain degree, overlooks the predominance of such lineages in certain non-temperate areas. Here, we further discuss and present new information about the overwhelming dominance of temperate VZV genotypes in Mexico regardless of geographical location and climate.</p> <p>Summary</p> <p>UV radiation does not satisfactorily explain the distribution of VZV genotypes in different tropical and temperate regions of Mexico. Additionally, the cyclic behavior of varicella does not shown significant differences between regions with different climates in the country. More studies should be conducted to identify the factors directly involved in viral spreading. A better understanding of the modes of transmissions exploited by VZV and their effect on viral fitness is likely to facilitate the implementation of preventive measures for disease control.</p
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