2,196 research outputs found

    Bioaccumulation of PCB & DDE methyl sulfones in marine mammals and their interactions with receptor proteins

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    PCB and DDE-Methyl sulphone metabolites are the product of enzymatic and bile acid entero hepatic metabolism in the final phase (III) of PCB and DDE detoxification in mammals following hepatic microsomal cytochrome P450-dependent metabolism (phase I) and conjugation (phase II). There is good evidence that PCB and DDE methyl sulphone (MSF) metabolites interfere with steroid binding to a receptor protein in uterine epithelium (uteroglobin - UG2 and bronchial epithelium (clara cell secretory protein - CCSP). UG and CCSP are homologous 16,000 Da proteins with different tissue-specific functions. UG binds progesterone in the pre-implantation uterus to signal localised endometrial thickening and capillary formation, vital for successful attachment of the fertilised embryo. PCB-MSFs can displace progesterone in the mammalian uterus due to their higher affinity for UG, resulting in implantation failure or early fetal death. CCSP however, functions to sequester phospholipase A2 (PLA2) released in response to stress (pathogenic infection / injury) to suppress inflammatory responses triggered by PLA2 in bronchial epithelium. CCSP is also known as retinol-binding protein (RBP) transporting retinol (vit A) to target epithelia for a functional immune response*. Studies with Harbour Seals demonstrated displacement of retinol from RBP by hydroxy-PCB metabolites resulting in immunosuppression. PCB-MSFs have been shown to accumulate in clara cells and uterine epithelium in laboratory radioactive tracer studies and CCSP-knock out studies with mice. PCB and DDE -MSFs burdens have been found in marine mammals, suggesting they may be subject to reproductive and immuno-toxic effects of these metabolites. This study determines PCB and DDE-MSFs burdens in tissues (including lung & uterus) of Harbour Seal (Phoca vitulina) and Striped Dolphin (Stenella coeruleoalba) morbillivirus victims and characterises the marine mammalian UG/CCSP protein

    Els conjunts patrimonials com a elements generadors de recursos

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    La necessitat de fer compatibles els beneficis pedagògics i divulgatius del patrimoni, reflectits en el seu rendiment social i cultural, amb els econòmics que permetin la dinamització i autofinançament d'aquest, és l'eix expositiu d'aquesta comunicació. Els orígens i història del projecte de les Mines Prehistòriques de Gavà, fent balanç de la seva experiència en els darrers sis anys, conclouen l'exposició tot recordant els àmbits d'actuació d'aquest: investigació, conservació i divulgació. L'Escola Taller Museu de Gavà ha estat una eina important per poder conjugar i posar en relació cadascun d'aquests aspectes.La necesidad de hacer compatibles los beneficios pedagógicos y divulgativos del patrimonio, reflejados en su rendimiento social y cultural, con los económicos que permitan la dinamización y autofinanciación de éste, es el eje expositivo de esta comunicación. Los orígens y història del proyecto de las Minas Prehistóricas de Gavà, haciendo balance de su experiencia en los últimos seis años, concluyen la exposición recordando los ámbitos de actuación de éste: investigación, conservación y divulgación. La Escola Taller Museu de Gavà ha sido un instrumento importante para poder conjugar y poner en relación cada uno de estos aspectos

    Learning Koopman eigenfunctions of stochastic diffusions with optimal importance sampling and ISOKANN

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    The dominant eigenfunctions of the Koopman operator characterize the metastabilities and slow-timescale dynamics of stochastic diffusion processes. In the context of molecular dynamics and Markov state modeling, they allow for a description of the location and frequencies of rare transitions, which are hard to obtain by direct simulation alone. In this article, we reformulate the eigenproblem in terms of the ISOKANN framework, an iterative algorithm that learns the eigenfunctions by alternating between short burst simulations and a mixture of machine learning and classical numerics, which naturally leads to a proof of convergence. We furthermore show how the intermediate iterates can be used to reduce the sampling variance by importance sampling and optimal control (enhanced sampling), as well as to select locations for further training (adaptive sampling). We demonstrate the usage of our proposed method in experiments, increasing the approximation accuracy by several orders of magnitude

    Calidad de los diagnósticos en urgencias de las lesiones por causas externas que requieren ingreso hospitalario

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    SummaryObjectiveTo establish the quality of emergency department diagnoses for those patients whose injuries required hospital admission.MethodsEmergency and hospital discharge diagnostics were retrieved for 339 injured patients. Severity scores (ISS) were calculated using an automatic conversion procedure (ICDMAP). Emergency diagnoses for each patient (grouped into categories) were compared with the hospital discharge ones. Quality was analyzed based on accuracy (Percy groups) and reliability (percentage of concordance) measurements. Severity scores were evaluated using reliability measures (percentage of concordance and intraclass correlation coefficient -ICC-).ResultsMean diagnoses per patient were 1.1 at the emergency department and 1.4 at hospital discharge. In the latter, there were diagnoses in each category except for those more unspecific, where there was a reduction. Overall,emergency information showed under notification. Severity scores were higher with hospital discharge data. There was a 63% percentage of concordance. When grouped into categories, severity scores had an ICC of 0.61 (moderate-good).ConclusionEmergency departments are a potential good source of information about injury severity even for those patients who require hospital admission. Emergency department injury surveillance can be very useful in assessing the magnitude and distribution of injury severity at the population level. Nevertheless for individual severity assessment, use of hospital discharge information is recommended

    Antimicrobial resistance in Mycobacterium tuberculosis : mechanistic and evolutionary perspectives

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    Antibiotic-resistant Mycobacterium tuberculosis strains are threatening progress in containing the global tuberculosis epidemic. Mycobacterium tuberculosis is intrinsically resistant to many antibiotics, limiting the number of compounds available for treatment. This intrinsic resistance is due to a number of mechanisms including a thick, waxy, hydrophobic cell envelope and the presence of drug degrading and modifying enzymes. Resistance to the drugs which are active against M. tuberculosis is, in the absence of horizontally transferred resistance determinants, conferred by chromosomal mutations. These chromosomal mutations may confer drug resistance via modification or overexpression of the drug target, as well as by prevention of prodrug activation. Drug resistance mutations may have pleiotropic effects leading to a reduction in the bacterium's fitness, quantifiable e.g. by a reduction in the in vitro growth rate. Secondary so-called compensatory mutations, not involved in conferring resistance, can ameliorate the fitness cost by interacting epistatically with the resistance mutation. Although the genetic diversity of M. tuberculosis is low compared to other pathogenic bacteria, the strain genetic background has been demonstrated to influence multiple aspects in the evolution of drug resistance. The rate of resistance evolution and the fitness costs of drug resistance mutations may vary as a function of the genetic background

    Enset‐based agricultural systems in Ethiopia: A systematic review of production trends, agronomy, processing and the wider food security applications of a neglected banana relative

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    Enset (Ensete ventricosum (Welw.) Cheesman) is the major starch staple of the Ethiopian Highlands, where its unique attributes enhance the food security of approximately 20 million people and have earned it the title “The Tree Against Hunger”. Yet enset‐based agriculture is virtually unknown outside of its narrow zone of cultivation, despite growing wild across much of East and Southern Africa. Here, we review historical production data to show that the area of land under enset production in Ethiopia has reportedly increased 46% in two decades, whilst yield increased 12‐fold over the same period, making enset the second most produced crop species in Ethiopia—though we critically evaluate potential issues with these data. Furthermore, we address a major challenge in the development and wider cultivation of enset, by reviewing and synthesizing the complex and fragmented agronomic and ethnobotanic knowledge associated with this species; including farming systems, processing methods, products, medicinal uses and cultural importance. Finally, we provide a framework to improve the quality, consistency and comparability of data collected across culturally diverse enset‐based agricultural systems to enhanced sustainable use of this neglected starch staple. In conclusion, we discuss the challenges and opportunities for enset cultivation beyond its restricted distribution, and the regional food security potential it could afford smallholders elsewhere in Southern and East Africa

    Un enfoque tolerante a interrupciones para la seguridad de la Internet de las cosas

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    La Internet de las cosas (IoT, Internet of Things) es un paradigma emergente que pretende la interconexión de cualquier objeto susceptible de contar con una parte de electrónica, favorecido por la miniaturización de los componentes. El estado de desarrollo de la IoT hace que no haya ninguna propuesta firme para garantizar la seguridad y la comunicación extremo a extremo. En este artículo presentamos un trabajo en progreso hacia una aproximación tolerante a retrasos (DTN, Delay and Disruption Tolerant Networks) para la comunicación en el paradigma de la IoT y planteamos la adaptación de los mecanismo de seguridad existentes en DTN a la IoT.Este trabajo ha sido parcialmente financiado por el Ministerio de Ciencia e Innovación Español, proyecto TIN2010-15764 y por la Generalitat de Cataluña, proyecto 2014SGR-619

    Agency and responsibility over virtual movements controlled through different paradigms of brain−computer interface

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    Agency is the attribution of an action to the self and is a prerequisite for experiencing responsibility over its consequences. Here we investigated agency and responsibility by studying the control of movements of an embodied avatar, via brain computer interface (BCI) technology, in immersive virtual reality. After induction of virtual body ownership by visuomotor correlations, healthy participants performed a motor task with their virtual body. We compared the passive observation of the subject's ‘own’ virtual arm performing the task with (1) the control of the movement through activation of sensorimotor areas (motor imagery) and (2) the control of the movement through activation of visual areas (steady‐state visually evoked potentials). The latter two conditions were carried out using a brain–computer interface (BCI) and both shared the intention and the resulting action. We found that BCI‐control of movements engenders the sense of agency, which is strongest for sensorimotor areas activation. Furthermore, increased activity of sensorimotor areas, as measured using EEG, correlates with levels of agency and responsibility. We discuss the implications of these results for the neural basis of agency

    Post-head-emergence frost in wheat and barley: defining the problem, assessing the damage, and identifying resistance

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    Radiant frost is a significant production constraint to wheat (Triticum aestivum) and barley (Hordeum vulgare), particularly in regions where spring-habit cereals are grown through winter, maturing in spring. However, damage to winter-habit cereals in reproductive stages is also reported. Crops are particularly susceptible to frost once awns or spikes emerge from the protection of the flag leaf sheath. Post-head-emergence frost (PHEF) is a problem distinct from other cold-mediated production constraints. To date, useful increased PHEF resistance in cereals has not been identified. Given the renewed interest in reproductive frost damage in cereals, it is timely to review the problem. Here we update the extent and impacts of PHEF and document current management options to combat this challenge. We clarify terminology useful for discussing PHEF in relation to chilling and other freezing stresses. We discuss problems characterizing radiant frost, the environmental conditions leading to PHEF damage, and the effects of frost at different growth stages. PHEF resistant cultivars would be highly desirable, to both reduce the incidence of direct frost damage and to allow the timing of crop maturity to be managed to maximize yield potential. A framework of potential adaptation mechanisms is outlined. Clarification of these critical issues will sharpen research focus, improving opportunities to identify genetic sources for improved PHEF resistance
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