1,044 research outputs found

    Validation of the detection of Alexandrium spp using specific RNA probes tested in a microarray format: Calibration of signal using variability of RNA content with environmental conditions

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    The dinoflagellate genus Alexandrium contains several toxin producing species and strains, which can cause major economic losses to the shell fish industry. It is therefore important to be able to detect these toxin producers and also distinguish toxic strains from some of the morphologically identical non-toxic strains. To facilitate this DNA probes to be used in a microarray format were designed in silico or developed from existing published probes. These probes targeted either the 18S or 28S ribosomal ribonucleic acid (rRNA) gene in Alexandrium tamarense Group I, Group III and Group IV, Alexandrium ostenfeldii and Alexandrium minutum. Three strains of A. tamarense Group I, A. tamarense Group III, A. minutum and two strains of A. ostenfeldii were grown at optimal conditions and transferred into new environmental conditions changing either the light intensity, salinity, temperature or nutrient concentrations, to check if any of these environmental conditions induced changes in the cellular ribonucleic acid (RNA) concentration or growth rate. The aim of this experiment was the calibration of several species-specific probes for the quantification of the toxic Alexandrium strains. Growth rates were highly variable but only elevated or lowered salinity significantly lowered growth rate for A. tamarense Group I and Group III; differences in RNA content were not significant for the majority of the treatments. Only light intensity seemed to affect significantly the RNA content in A. tamarense Group I and Group III, but this was still within the same range as for the other treatments meaning that a back calibration from RNA to cell numbers was possible. The designed probes allow the production of quantitative information for Alexandrium species for the microarray chip

    Preliminary results of the MIDTAL project: a microarray chip to monitor toxic dinoflagellates in the Orkney Islands, U.K.

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    Harmful algae can cause economic damage to fisheries and tourism. Additionally, toxins produced by harmful algae and ingested via contaminated shellfish can be potentially fatal to humans. Monitoring these harmful algae can be difficult as determining cell morphology by light microscopy may be insufficient to give definitive species attribution. The goal of the EU FP7 project MIDTAL (microarrays for the detection of toxic algae) was to achieve rapid species identification using species specific probes for rRNA genes in a microarray chip format. Field samples from the Orkney Islands, an area of the U.K. that has a number of nuisance and toxic species were tested with the second generation of the microarray chip. Species specific probes were looked at for the toxin producing dinoflagellates Alexandrium tamarense Group III (North American clade) and Dinophysis acuta and also general class probes for Dinophyta, Heterokontaphyta and Prymnesiophyta over the course of a year. These were compared with light microscopy cell counts. A good agreement in determining presence and absence between the methods was found. The second generation microarray is potentially more sensitive than cell counts. However, further work is needed to ensure that the microarray signal for each species provides an accurate quantitative assessment

    Are pregnancy outcomes associated with risk factor reporting in routinely collected perinatal data?

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    Relatório de estágio do mestrado em Ensino da Educação Física dos Ensinos Básico e Secundário, apresentado à Faculdade de Ciências do Desporto e Educação Física da Universidade de CoimbraApresentado como um documento reflexivo e figurativo das experiências e vivências tidas durante o ano de Estágio Pedagógico em Ensino da Educação Física nos Ensinos Básico e Secundário, este relatório final foi desenvolvido com base no contexto da Turma do 11º PS da Escola Secundária de Avelar Brotero, contendo, assim, todas as expetativas, conceções, aprendizagens, dificuldades, estratégias, soluções e etapas superadas. Estruturado em cinco capítulos – Enquadramento pessoal onde consta as expetativas iniciais relativas ao Estágio Pedagógico; contextualização da prática desenvolvida, onde caracterizamos o contexto; realização da prática profissional, da qual consta uma reflexão sobre todo o processo de planeamento, realização e avaliação; reflexões acerca do processo pedagógico, onde expomos opiniões edificantes dos desafios e dilemas na condução do processo de ensino-aprendizagem; e o aprofundamento do tema problema – foi evidenciado o caminho que fomos (re)construindo com identidade, partilha e reflexão, e a forma como encaramos o compromisso com as aprendizagens dos alunos. Fundamentado no paradigma construtivista, o desenvolvimento curricular foi neste relatório assumido como um processo que deverá centrar-se no aluno, aludindo ao conjunto de estratégias, métodos e procedimentos que permitem a concretização de um projeto de formação pessoal e social que a prática desportiva pode potenciar. Tendo em atenção os contextos e cenários de aprendizagem, os papéis e responsabilidades de quem ensina e de quem aprende, fomos delegando ao aluno autonomia, iniciativa, criatividade, capacidade de cooperação e entreajuda, capacidade de decidir, vontade de aprender e de praticar. O Modelo de Educação Desportiva, enquanto modelo de ensino, foi um marco neste processo, pelo que foi objeto de um estudo mais aprofundado. This document was presented as a reflective essay on the experiences lived during the year of Practicum in Teaching of Physical Education on learning stages of Elementary School and High School. This final report was based on the class of 11º PS of Avelar Brotero’s High School, and represents all the expectations, conceptions, learning skills, difficulties found in the process, strategies adopted, solutions found and overcome barriers. It was structured in five chapters: initial expectations relating to the Practicum; characterization of the context; professional practice, in which lies was a reflexion about all the process of planning, making and evaluation; problems and challenges occurred during the process of teaching and learning; and finally deep reflection about he main theme - was then noted the way in which we had been (re)building our study with identity, sharing and reflexion and the way we faced the commitment with the students own learning skills and paths. Under the influence of the constructivist paradigm, curriculum development was seen as a process that will focus on the student, alluding to the set of strategies, methods and procedures that allow the making of a project of personal and social development that the sports practice may enhance, delegating the student autonomy, responsibility, initiative, creativity, ability to cooperate and assist others, and ability to learn and share. The Sport Education Model while teaching model it was a milestone in this process, whereat it was object of further study

    Investigating linkage rates among probabilistically linked birth and hospitalization records

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    BACKGROUND: With the increasing use of probabilistically linked administrative data in health research, it is important to understand whether systematic differences occur between the populations with linked and unlinked records. While probabilistic linkage involves combining records for individuals, population perinatal health research requires a combination of information from both the mother and her infant(s). The aims of this study were to (i) describe probabilistic linkage for perinatal records in New South Wales (NSW) Australia, (ii) determine linkage proportions for these perinatal records, and (iii) assess records with linked mother and infant hospital-birth record, and unlinked records for systematic differences. METHODS: This is a population-based study of probabilistically linked statutory birth and hospital records from New South Wales, Australia, 2001-2008. Linkage groups were created where the birth record had complete linkage with hospital admission records for both the mother and infant(s), partial linkage (the mother only or the infant(s) only) or neither. Unlinked hospital records for mothers and infants were also examined. Rates of linkage as a percentage of birth records and descriptive statistics for maternal and infant characteristics by linkage groups were determined. RESULTS: Complete linkage (mother hospital record – birth record – infant hospital record) was available for 95.9% of birth records, partial linkage for 3.6%, and 0.5% with no linked hospital records (unlinked). Among live born singletons (complete linkage = 96.5%) the mothers without linked infant records (1.6%) had slightly higher proportions of young, non-Australian born, socially disadvantaged women with adverse pregnancy outcomes. The unlinked birth records (0.4%) had slightly higher proportions of nulliparous, older, Australian born women giving birth in private hospitals by caesarean section. Stillbirths had the highest rate of unlinked records (3-4%). CONCLUSIONS: This study shows that probabilistic linkage of perinatal records can achieve high, representative levels of complete linkage. Records for mother’s that did not link to infant records and unlinked records had slightly different characteristics to fully linked records. However, these groups were small and unlikely to bias results and conclusions in a substantive way. Stillbirths present additional challenges to the linkage process due to lower rates of linkage for lower gestational ages, where most stillbirths occur

    Potential prevention of small for gestational age in Australia: a population-based linkage study

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    BACKGROUND: Small for gestational age (SGA) infants are at increased risk of morbidity and mortality. We sought to identify risk factors associated with SGA and examined the potential for reducing the proportion of infants with SGA at a population level. METHODS: Birth and hospital records were linked for births occurring in 2007–2010 in New South Wales, Australia. The analysis was stratified into three groups: preterm births, term births to non-diabetic mothers and term births to diabetic mothers. Logistic regression was used to examine the association between SGA and a range of socio-demographic and behavioural factors and health conditions, with generalised estimating equations to account for correlation among births to the same mother. Model-based population attributable fractions (PAFs) were calculated for risk factors that were considered causative and potentially modifiable. RESULTS: Of 28,126 SGA infants, the largest group was term infants of non-diabetic mothers (88.5%), followed by term infants of diabetic mothers (6.3%) and preterm infants (5.3%). The highest PAFs were for smoking: 12.4% for preterm SGA and 10.3% for term SGA infants of non-diabetic mothers. Other risk factors for SGA that were considered modifiable included: illicit drug dependency or abuse in pregnancy in all three groups, and pregnancy hypertension and late commencement of antenatal care in term infants of non-diabetic mothers, but PAFs were less than 3%. CONCLUSIONS: There are opportunities for modest reduction of the prevalence of SGA through reduction in smoking in pregnancy, and possibly earlier commencement of antenatal care and improved management of high-risk pregnancies

    Circular polarization in n-type resonant tunneling diodes with Si delta-doping in the quantum well

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    In this work, we have investigated magneto-transport and polarization resolved photoluminescence of a GaAs/AlGaAs resonant tunneling diode with Si delta-doping at the center of the quantum well under a magnetic field parallel to the tunnel current. Three resonant peaks were observed in the current-voltage characteristics curve (J(V)) which were associated to donor-assisted resonant tunneling, electron resonant tunneling and to phonon-­assisted resonant tunneling. The optical emission from GaAs contact layers shows evidence of highly spin-polarized two-dimensional electron and hole gases which affect the spin-polarization of carriers in the well. The quantum well photoluminescence shows strong circular polarization degrees with values up to 85% under 15T at the donor assisted resonant tunneling peak voltage. Our results can be exploited for future development of voltage-controlled spintronics devices

    Novel 4, 8-benzobisthiazole copolymers and their field-effect transistor and photovoltaic applications

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    A series of copolymers containing the benzo[1,2-d:4,5-d′]bis(thiazole) (BBT) unit has been designed and synthesised with bisthienyl-diketopyrrolopyrrole (DPP), dithienopyrrole (DTP), benzothiadiazole (BT), benzodithiophene (BDT) or 4,4′-dialkoxybithiazole (BTz) comonomers. The resulting polymers possess a conjugation pathway that is orthogonal to the more usual substitution pathway through the 2,6-positions of the BBT unit, facilitating intramolecular non-covalent interactions between strategically placed heteroatoms of neighbouring monomer units. Such interactions enable a control over the degree of planarity through altering their number and strength, in turn allowing for tuning of the band gap. The resulting 4,8-BBT materials gave enhanced mobility in p-type organic field-effect transistors of up to 2.16 × 10−2 cm2 V−1 s−1 for pDPP2ThBBT and good solar cell performance of up to 4.45% power conversion efficiency for pBT2ThBBT

    Precise spatio-temporal control of rapid optogenetic cell ablation with mem-KillerRed in Zebrafish

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    The ability to kill individual or groups of cells in vivo is important for studying cellular processes and their physiological function. Cell-specific genetically encoded photosensitizing proteins, such as KillerRed, permit spatiotemporal optogenetic ablation with low-power laser light. We report dramatically improved resolution and speed of cell targeting in the zebrafish kidney through the use of a selective plane illumination microscope (SPIM). Furthermore, through the novel incorporation of a Bessel beam into the SPIM imaging arm, we were able to improve on targeting speed and precision. The low diffraction of the Bessel beam coupled with the ability to tightly focus it through a high NA lens allowed precise, rapid targeting of subsets of cells at anatomical depth in live, developing zebrafish kidneys. We demonstrate that these specific targeting strategies significantly increase the speed of optoablation as well as fish survival

    The role of Schizosaccharomyces pombe SUMO ligases in genome stability

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    SUMOylation is a post-translational modification that affects a large number of proteins, many of which are nuclear. While the role of SUMOylation is beginning to be elucidated, it is clear that understanding the mechanisms that regulate the process is likely to be important. Control of the levels of SUMOylation is brought about through a balance of conjugating and deconjugating activities, i.e. of SUMO (small ubiquitin-related modifier) conjugators and ligases versus SUMO proteases. Although conjugation of SUMO to proteins can occur in the absence of a SUMO ligase, it is apparent that SUMO ligases facilitate the SUMOylation of specific subsets of proteins. Two SUMO ligases in Schizosaccharomyces pombe, Pli1 and Nse2, have been identified, both of which have roles in genome stability. We report here on a comparison between the properties of the two proteins and discuss potential roles for the proteins
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