871 research outputs found

    The environmental security debate and its significance for climate change

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    Policymakers, military strategists and academics all increasingly hail climate change as a security issue. This article revisits the (comparatively) long-standing “environmental security debate” and asks what lessons that earlier debate holds for the push towards making climate change a security issue. Two important claims are made. First, the emerging climate security debate is in many ways a re-run of the earlier dispute. It features many of the same proponents and many of the same disagreements. These disagreements concern, amongst other things, the nature of the threat, the referent object of security and the appropriate policy responses. Second, given its many different interpretations, from an environmentalist perspective, securitisation of the climate is not necessarily a positive development

    Dynamic biospeckle analysis, a new tool for the fast screening of plant nematicide selectivity

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    Background: Plant feeding, free-living nematodes cause extensive damage to plant roots by direct feeding and, in the case of some trichodorid and longidorid species, through the transmission of viruses. Developing more environmentally friendly, target-specific nematicides is currently impeded by slow and laborious methods of toxicity testing. Here, we developed a bioactivity assay based on the dynamics of light 'speckle' generated by living cells and we demonstrate its application by assessing chemicals' toxicity to different nematode trophic groups.Results: Free-living nematode populations extracted from soil were exposed to methanol and phenyl isothiocyanate (PEITC). Biospeckle analysis revealed differing behavioural responses as a function of nematode feeding groups. Trichodorus nematodes were less sensitive than were bacterial feeding nematodes or non-trichodorid plant feeding nematodes. Following 24 h of exposure to PEITC, bioactivity significantly decreased for plant and bacterial feeders but not for Trichodorus nematodes. Decreases in movement for plant and bacterial feeders in the presence of PEITC also led to measurable changes to the morphology of biospeckle patterns.Conclusions: Biospeckle analysis can be used to accelerate the screening of nematode bioactivity, thereby providing a fast way of testing the specificity of potential nematicidal compounds. With nematodes' distinctive movement and activity levels being visible in the biospeckle pattern, the technique has potential to screen the behavioural responses of diverse trophic nematode communities. The method discriminates both behavioural responses, morphological traits and activity levels and hence could be used to assess the specificity of nematicidal compounds.</p

    A statistical approach to quantitative data validation focused on the assessment of students' perceptions about biotechnology

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    Student awareness levels are frequently used to evaluate the effectiveness of educational policies to promote scientific literacy. Over the last years several studies have been developed to assess students' perceptions towards science and technology, which usually rely on quantitative methods to achieve broad characterizations, and obtain quantifiable and comparable data. Although the usefulness of this information depends on its validity and reliability, validation is frequently neglected by researchers with limited background in statistics. In this context, we propose a guideline to implement a statistical approach to questionnaire validation, combining exploratory factor analysis and reliability analysis. The work focuses on the psychometric analysis of data provided by a questionnaire assessing 1196 elementary and high school students' perceptions about biotechnology. Procedural guidelines to enhance the efficiency of quantitative inquiry surveys are given, by discussing essential methodological aspects and relevant criteria to integrate theory into practice.The authors are grateful to all the participant teachers and students that contributed to gather the data presented and to Catarina L. Santos for useful comments and suggestions on the manuscript. Maria Joao Fonseca was supported by the FCT fellowship SFRH/BD/37389/2007 and this work was sponsored by a research grant (PTDC/AGR-PRO/111857/2009) from Fundacao para a Ciencia e Tecnologia (FCT, Portugal)

    The Complete Genome Sequence of Escherichia coli EC958: A High Quality Reference Sequence for the Globally Disseminated Multidrug Resistant E. coli O25b:H4-ST131 Clone

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    Escherichia coli ST131 is now recognised as a leading contributor to urinary tract and bloodstream infections in both community and clinical settings. Here we present the complete, annotated genome of E. coli EC958, which was isolated from the urine of a patient presenting with a urinary tract infection in the Northwest region of England and represents the most well characterised ST131 strain. Sequencing was carried out using the Pacific Biosciences platform, which provided sufficient depth and read-length to produce a complete genome without the need for other technologies. The discovery of spurious contigs within the assembly that correspond to site-specific inversions in the tail fibre regions of prophages demonstrates the potential for this technology to reveal dynamic evolutionary mechanisms. E. coli EC958 belongs to the major subgroup of ST131 strains that produce the CTX-M-15 extended spectrum β-lactamase, are fluoroquinolone resistant and encode the fimH30 type 1 fimbrial adhesin. This subgroup includes the Indian strain NA114 and the North American strain JJ1886. A comparison of the genomes of EC958, JJ1886 and NA114 revealed that differences in the arrangement of genomic islands, prophages and other repetitive elements in the NA114 genome are not biologically relevant and are due to misassembly. The availability of a high quality uropathogenic E. coli ST131 genome provides a reference for understanding this multidrug resistant pathogen and will facilitate novel functional, comparative and clinical studies of the E. coli ST131 clonal lineage

    An interview with Eustáquio A. Araujo

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    Psychological responses to the proximity of climate change

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    A frequent suggestion to increase individuals’ willingness to take action on climate change and to support relevant policies is to highlight its proximal consequences. However, previous studies that have tested this proximising approach have not revealed the expected positive effects on individual action and support for addressing climate change. We present three lines of psychological reasoning that provide compelling arguments as to why highlighting proximal impacts of climate change might not be as effective a way to increase individual mitigation and adaptation efforts as is often assumed. Our contextualisation of the proximising approach within established psychological research suggests that, depending on the particular theoretical perspective one takes to this issue, and on specific individual characteristics suggested by these perspectives, proximising can bring about the intended positive effects, can have no (visible) effect, or can even backfire. Thus, the effects of proximising are much more complex than is commonly assumed. Revealing this complexity contributes to a refined theoretical understanding of the role psychological distance plays in the context of climate change and opens up further avenues for future research and for interventions

    The Directly Observed Therapy Short-Course (DOTS) strategy in Samara Oblast, Russian Federation

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    BACKGROUND: The World Health Organisation (WHO) defines Russia as one of the 22 highest-burden countries for tuberculosis (TB). The WHO Directly Observed Treatment Short Course (DOTS) strategy employing a standardised treatment for 6 months produces the highest cure rates for drug sensitive TB. The Russian TB service traditionally employed individualised treatment. The purpose of this study was to implement a DOTS programme in the civilian and prison sectors of Samara Region of Russia, describe the clinical features and outcomes of recruited patients, determine the proportion of individuals in the cohorts who were infected with drug resistant TB, the degree to which resistance was attributed to the Beijing TB strain family and establish risk factors for drug resistance. METHODS: prospective study RESULTS: 2,099 patients were recruited overall. Treatment outcomes were analysed for patients recruited up to the third quarter of 2003 (n = 920). 75.3% of patients were successfully treated. Unsuccessful outcomes occurred in 7.3% of cases; 3.6% of patients died during treatment, with a significantly higher proportion of smear-positive cases dying compared to smear-negative cases. 14.0% were lost and transferred out. A high proportion of new cases (948 sequential culture-proven TB cases) had tuberculosis that was resistant to first-line drugs; (24.9% isoniazid resistant; 20.3% rifampicin resistant; 17.3% multidrug resistant tuberculosis). Molecular epidemiological analysis demonstrated that half of all isolated strains (50.7%; 375/740) belonged to the Beijing family. Drug resistance including MDR TB was strongly associated with infection with the Beijing strain (for MDR TB, 35.2% in Beijing strains versus 9.5% in non-Beijing strains, OR-5.2. Risk factors for multidrug resistant tuberculosis were: being a prisoner (OR 4.4), having a relapse of tuberculosis (OR 3.5), being infected with a Beijing family TB strain (OR 6.5) and having an unsuccessful outcome from treatment (OR 5.0). CONCLUSION: The implementation of DOTS in Samara, Russia, was feasible and successful. Drug resistant tuberculosis rates in new cases were high and challenge successful outcomes from a conventional DOTS programme alone

    The core genome of the anaerobic oral pathogenic bacterium Porphyromonas gingivalis

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    <p>Abstract</p> <p>Background</p> <p>The Gram negative anaerobic bacterium <it>Porphyromonas gingivalis </it>has long been recognized as a causative agent of periodontitis. Periodontitis is a chronic infectious disease of the tooth supporting tissues eventually leading to tooth-loss. Capsular polysaccharide (CPS) of <it>P. gingivalis </it>has been shown to be an important virulence determinant. Seven capsular serotypes have been described. Here, we used micro-array based comparative genomic hybridization analysis (CGH) to analyze a representative of each of the capsular serotypes and a non-encapsulated strain against the highly virulent and sequenced W83 strain. We defined absent calls using <it>Arabidopsis thaliana </it>negative control probes, with the aim to distinguish between aberrations due to mutations and gene gain/loss.</p> <p>Results</p> <p>Our analyses allowed us to call aberrant genes, absent genes and divergent regions in each of the test strains. A conserved core <it>P. gingivalis </it>genome was described, which consists of 80% of the analyzed genes from the sequenced W83 strain. The percentage of aberrant genes between the test strains and control strain W83 was 8.2% to 13.7%. Among the aberrant genes many CPS biosynthesis genes were found. Most other virulence related genes could be found in the conserved core genome. Comparing highly virulent strains with less virulent strains indicates that <it>hmuS, </it>a putative CobN/Mg chelatase involved in heme uptake, may be a more relevant virulence determinant than previously expected. Furthermore, the description of the 39 W83-specific genes could give more insight in why this strain is more virulent than others.</p> <p>Conclusion</p> <p>Analyses of the genetic content of the <it>P. gingivalis </it>capsular serotypes allowed the description of a <it>P. gingivalis </it>core genome. The high resolution data from three types of analysis of triplicate hybridization experiments may explain the higher divergence between <it>P. gingivalis </it>strains than previously recognized.</p

    Coupling changes in cell shape to chromosome segregation

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    Animal cells undergo dramatic changes in shape, mechanics and polarity as they progress through the different stages of cell division. These changes begin at mitotic entry, with cell–substrate adhesion remodelling, assembly of a cortical actomyosin network and osmotic swelling, which together enable cells to adopt a near spherical form even when growing in a crowded tissue environment. These shape changes, which probably aid spindle assembly and positioning, are then reversed at mitotic exit to restore the interphase cell morphology. Here, we discuss the dynamics, regulation and function of these processes, and how cell shape changes and sister chromatid segregation are coupled to ensure that the daughter cells generated through division receive their fair inheritance
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