870 resultados para new technologies in teaching
Resumo:
Resume : L'utilisation de l'encre comme indice en sciences forensiques est décrite et encadrée par une littérature abondante, comprenant entre autres deux standards de l'American Society for Testing and Materials (ASTM). La grande majorité de cette littérature se préoccupe de l'analyse des caractéristiques physiques ou chimiques des encres. Les standards ASTM proposent quelques principes de base qui concernent la comparaison et l'interprétation de la valeur d'indice des encres en sciences forensiques. L'étude de cette littérature et plus particulièrement des standards ASTM, en ayant a l'esprit les développements intervenus dans le domaine de l'interprétation de l'indice forensique, montre qu'il existe un potentiel certain pour l'amélioration de l'utilisation de l'indice encre et de son impact dans l'enquête criminelle. Cette thèse propose d'interpréter l'indice encre en se basant sur le cadre défini par le théorème de Bayes. Cette proposition a nécessité le développement d'un système d'assurance qualité pour l'analyse et la comparaison d'échantillons d'encre. Ce système d'assurance qualité tire parti d'un cadre théorique nouvellement défini. La méthodologie qui est proposée dans ce travail a été testée de manière compréhensive, en tirant parti d'un set de données spécialement créer pour l'occasion et d'outils importés de la biométrie. Cette recherche répond de manière convaincante à un problème concret généralement rencontré en sciences forensiques. L'information fournie par le criminaliste, lors de l'examen de traces, est souvent bridée, car celui-ci essaie de répondre à la mauvaise question. L'utilisation d'un cadre théorique explicite qui définit et formalise le goal de l'examen criminaliste, permet de déterminer les besoins technologiques et en matière de données. Le développement de cette technologie et la collection des données pertinentes peut être justifiées économiquement et achevée de manière scientifique. Abstract : The contribution of ink evidence to forensic science is described and supported by an abundant literature and by two standards from the American Society for Testing and Materials (ASTM). The vast majority of the available literature is concerned with the physical and chemical analysis of ink evidence. The relevant ASTM standards mention some principles regarding the comparison of pairs of ink samples and the evaluation of their evidential value. The review of this literature and, more specifically, of the ASTM standards in the light of recent developments in the interpretation of forensic evidence has shown some potential improvements, which would maximise the benefits of the use of ink evidence in forensic science. This thesis proposes to interpret ink evidence using the widely accepted and recommended Bayesian theorem. This proposition has required the development of a new quality assurance process for the analysis and comparison of ink samples, as well as of the definition of a theoretical framework for ink evidence. The proposed technology has been extensively tested using a large dataset of ink samples and state of the art tools, commonly used in biometry. Overall, this research successfully answers to a concrete problem generally encountered in forensic science, where scientists tend to self-limit the usefulness of the information that is present in various types of evidence, by trying to answer to the wrong questions. The declaration of an explicit framework, which defines and formalises their goals and expected contributions to the criminal and civil justice system, enables the determination of their needs in terms of technology and data. The development of this technology and the collection of the data is then justified economically, structured scientifically and can be proceeded efficiently.
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Although the T-cell receptor αδ (TCRαδ) locus harbours large libraries of variable (TRAV) and junctional (TRAJ) gene segments, according to previous studies the TCRα chain repertoire is of limited diversity due to restrictions imposed by sequential coordinate TRAV-TRAJ recombinations. By sequencing tens of millions of TCRα chain transcripts from naive mouse CD8(+) T cells, we observed a hugely diverse repertoire, comprising nearly all possible TRAV-TRAJ combinations. Our findings are not compatible with sequential coordinate gene recombination, but rather with a model in which contraction and DNA looping in the TCRαδ locus provide equal access to TRAV and TRAJ gene segments, similarly to that demonstrated for IgH gene recombination. Generation of the observed highly diverse TCRα chain repertoire necessitates deletion of failed attempts by thymic-positive selection and is essential for the formation of highly diverse TCRαβ repertoires, capable of providing good protective immunity.
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"In the nineties, dialogue in the Irish education system has been frenetic and painful at times. But it has gradually led to an extraordinary cohesion and partnership in the system. The book tracks the major consultations - and confrontations - of the nineties and it explores the personalities and policies of the protagonists - ministers, officials, leaders of Church bodies and third-level institutions, representatives of teachers' unions and parents' organisations." "All of the important consultation documents of the decade are here, the various drafts of the Green and White Papers - some benign, some infamous - the Bills, the Acts. The big issues are expertly set forth - intermediate structures and regionalisation, school governance and boards of management, the role of the Churches, higher education and the abolition of tuition fees."-This resource was contributed by The National Documentation Centre on Drug Use.
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Capillary zone electrophoresis (CZE) with UV detection has been widely used for the determination of carbohydrate-deficient transferrin (CDT), an indirect marker of the chronic alcohol consumption (≥60-80g/day). A commercially available method (CEofix? CDT kit), containing a bilayer anionic coating, allows for the analysis of CDT with a high resolution between transferrin (Tf) glycoforms with reduced protein adsorption onto the capillary wall. Although widely used in routine analysis, this procedure presents some limitations in terms of selectivity and sensitivity which may be overcome with mass spectrometry (MS). However, the available method is not MS-compatible due to the non-volatile coating as well as the phosphate and borate buffers present in the background electrolyte (BGE). This study firstly consisted in developing MS-compatible separation conditions, i.e., coating and BGE compositions. Numerous cationic, neutral, and anionic coatings were evaluated in combination with BGEs covering a broad range of pH values. A bilayer coating composed of a cationic layer of 10% polybrene (m/v) and an anionic layer of 10% dextran sulfate (m/v) combined with a BGE composed of 20mM ammonium acetate at pH 8.5 provided the best results in terms of glycoforms' resolution, efficiency, adsorption reduction, migration times' repeatability, and coating stability. The method was then transferred to CZE-MS after investigations of the electrospray ionization (ESI) source, equipped with a sheath-flow interface, and the time-of-flight (TOF/MS) parameters. A successful MS detection of tetrasialo-Tf was obtained during infusion, while the experiments highlighted the challenges and issues encountered with intact glycoprotein analysis by CZE-ESI-MS.
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In this paper we examine the problem of compositional data from a different startingpoint. Chemical compositional data, as used in provenance studies on archaeologicalmaterials, will be approached from the measurement theory. The results will show, in avery intuitive way that chemical data can only be treated by using the approachdeveloped for compositional data. It will be shown that compositional data analysis is aparticular case in projective geometry, when the projective coordinates are in thepositive orthant, and they have the properties of logarithmic interval metrics. Moreover,it will be shown that this approach can be extended to a very large number ofapplications, including shape analysis. This will be exemplified with a case study inarchitecture of Early Christian churches dated back to the 5th-7th centuries AD
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Celiac disease (CD) is a common autoimmune disorder characterized by an immune response to ingested gluten and has a strong HLA association with HLA-DQ2 and HLA-DQ8 molecules, but human HLA-DQ risk factors do not explain the entire genetic susceptibility to gluten intolerance. CD is caused by the lack of immune tolerance (oral tolerance) to wheat gluten. In this sense, the expression of soluble HLA-G in CD is of special interest because the molecule plays an important role in the induction of immune tolerance. The enhanced expression of soluble HLA-G found in CD may be part of a mechanism to restore the gluten intolerance. In this editorial, we review recent progress in understanding CD in relation to its prevalence, diagnosis and possible mechanisms of pathogenesis.
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Over the last 10 years, Uruguay, Chile and Brazil have been certified as being free from disease transmission by Triatoma infestans, the main domiciliated vector for Chagas disease in the Southern Cone countries. This demonstrates that programmes addressing the vector for the disease's transmission are effective. These programmes have resulted in a dramatic decrease in the incidence of Chagas disease in Latin America. Guatemala was certified a few months ago as being free from disease transmission by Rhodnius prolixus, the main domiciliated vector for Chagas disease in Central American countries. However, the main concern for different countries' current control programmes is the continuity and sustainability of future vector control actions. The prevalence and incidence figures for individuals infected by Trypanosoma cruzi in Mexico and Andean and Central American countries highlights the need for broadened strategies in the struggle against the disease and its vectors. A number of triatomine insects are parasite vectors, each with a different life history. Therefore, it is important that new vector control strategies be proposed, keeping in mind that some species are found in peridomiciliary areas and wild ecotopes. The only viable control strategy is to reduce human interactions with vector insects so that the re-infestation and re-colonisation of human habitats will not take place.
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New products available for food creations include a wide variety of "supposed" food grade aerosol sprays. However, the gas propellants used cannot be considered as safe. The different legislations available did not rule any maximum residue limits, even though these compounds have some limits when used for other food purposes. This study shows a preliminary monitoring of propane, butane and dimethyl ether residues, in cakes and chocolate after spraying, when these gases are used as propellants in food aerosol sprays. Release kinetics of propane, butane and dimethyl ether were measured over one day with sprayed food, left at room temperature or in the fridge after spraying. The alkanes and dimethyl ether analyses were performed by headspace-gas chromatography-mass spectrometry/thermal conductivity detection, using monodeuterated propane and butane generated in situ as internal standards. According to the obtained results and regardingthe extrapolations of the maximum residue limits existing for these substances, different delays should be respected according to the storage conditions and the gas propellant to consume safely the sprayed food.
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In 2004, Aedes (Stegomyia) albopictus (Skuse, 1894) was observed for the first time in Catalonia, northeastern Spain. A decade later, it has spread throughout the eastern Mediterranean region of the country and the Balearic Islands. Framed within a national surveillance project, we present the results of monitoring in 2013 in the autonomous communities of the mainland Levante. The current study reveals a remarkable increase in the spread of the invasive mosquito in relation to results from 2012; the species was present and well-established in 48 municipalities, most of which were along the Mediterranean coastline from the Valencian Community to the Region of Murcia.