3,140 research outputs found

    Influence of human pressures on large river structure and function

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    A large river study was conducted as part of the Cross Departmental Research Pool (CDRP) ecological integrity project to (i) provide an overview of the macroinvertebrate faunas of large rivers, including those in deep-water habitats, and (ii) to elucidate links between these faunas, river function and anthropogenic stressors. Eleven sites on 6th-order or 7th-order rivers were sampled; four in the South Island and seven in the North Island. We measured (i) macroinvertebrate communities colonising wood, riffles (where present), littoral habitats (1.5 m deep) (ii) ecosystem metabolism using a single-station open-channel approach based on natural changes in dissolved oxygen concentration over a 24-hour period, and (iii) wood and cellulose breakdown. Relationships were investigated between these response variables and reach-scale assessments of habitat quality, underlying upstream and segment environmental variables provided in the Freshwater Environments of New Zealand (FWENZ) database, and anthropogenic pressure variables provided by the Waters of National Importance (WONI) database

    A novel DRD2 single-nucleotide polymorphism associated with schizophrenia predicts age of onset: HapMap tag-sincle-nucleotide polymorphism analysis

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    Background: Dopamine D2 receptor (DRD2) is thought to be critical in regulating the dopaminergic pathway in the brain which is known to be important in the aetiology of schizophrenia. It is therefore not surprising that most antipsychotic medication acts on the Dopamine D2 receptor. DRD2 is widely expressed in brain, levels are reduced in brains of schizophrenia patients and DRD2 polymorphisms have been associated with reduced brain expression. We have previously identified a genetic variant in DRD2, rs6277 to be strongly implicated in schizophrenia susceptibility. Methods: To identity new associations in the DRD2 gene with disease status and clinical severity, we genotyped seven single nucleotide polymorphisms (SNPs) in DRD2 using a multiplex mass spectrometry method. SNPs were chosen using a haplotype block-based gene-tagging approach so the entire DRD2 gene was represented. Results: One polymorphism rs2734839 was found to be significantly associated with schizophrenia as well as late onset age. Individuals carrying the genetic variation were more than twice as likely to have schizophrenia compared to controls. Conclusions: Our results suggest that DRD2 genetic variation is a good indicator for schizophrenia risk and may also be used as a predictor age of onset

    International Migration, Population Change and the Labour Force, 1991-1996: An Overview

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    Between March 1991 and March 1996 the de facto population of New Zealand increased by around 225,000, the largest intercensal increase since the early 1970s. A short-lived surge in levels of natural increase in the early 1990s, coupled with some of the highest annual net migration gains since 1975, account for this substantial population growth. While there has been considerable comment in the media about the impact of this growth on the Auckland region in particular, the impacts which it has had on New Zealand's Labour force are less well known. This paper examines the components of change in labour force age groups between 1991 and 1996, isolating the impacts of immigration from those of structural change. The contrasting contributions to particular labour force age groups made by emigration of New Zealanders on the one hand, and immigration of citizens from other countries on the other, are then discussed. It is clear from the analysis that emigration and immigration are impacting quite differentially on the younger and older workforces. Some of the implications of these changes are explored with reference to the ageing labour force

    Genetic, environmental and gender influences on attachment disorder behaviours

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    Background Despite current interest in attachment disorder, there is concern about its discrimination from other disorders and an unproven assumption of an environmental aetiology. Aims To test whether behaviours suggestive of attachment disorder are distinct from other childhood behavioural and emotional problems and are solely environmentally determined. Method In a community sample of 13 472 twins, we carried out factor analysis of questionnaire items encompassing behaviours indicative of attachment disorder, conduct problems, hyperactivity and emotional difficulties. We used behavioural genetic model-fitting analysis to explore the contribution of genes and environment. Results Factor analysis showed clear discrimination between behaviours suggestive of attachment disorder, conduct problems, hyperactivity and emotional problems. Behavioural genetics analysis suggested a strong genetic influence to attachment disorder behaviour, with males showing higher heritability. Conclusions Behaviours suggestive of attachment disorder can be differentiated from common childhood emotional and behavioural problems and appear to be strongly genetically influenced, particularly in boys. INTRODUCTION TOP ABSTRACT INTRODUCTION METHOD RESULTS DISCUSSION REFERENCES There have been recent attempts to codify behaviours associated with early neglect and institutionalisation (Chisolm et al, 1995; Zeanah et al, 2004) into a psychiatric category. Both DSM–IV and ICD–10 describe reactive attachment disorder, with two subtypes encompassing inhibited and disinhibited behaviour (World Health Organization, 1992; American Psychiatric Association, 1994). Questions remain about the nosology of the syndrome beyond age 5 years (American Academy of Child and Adolescent Psychiatry, 2005), therefore we simply refer to ‘attachment disorder behaviours’. We seek to extend the extant literature by testing two hypotheses: first, that the two subtypes are distinct from one another and from other common behavioural and emotional problems in young children, and second that these behavioural patterns are environmentally mediated. We capitalise on a twin study, a design that provides particular leverage in testing environmental hypotheses

    Serrated Polyposis: An Enigmatic Model of Colorectal Cancer Predisposition

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    Serrated polyposis has only recently been accepted as a condition which carries an increased personal and familial risk of colorectal cancer. Described over four decades ago, it remains one of the most underrecognized and poorly understood of all the intestinal polyposes. With a variety of phenotypic presentations, it is likely that serrated polyposis represents a group of diseases rather than a single entity. Further, neoplastic progression in serrated polyposis may be associated with premature aging in the normal mucosa, typified by widespread gene promoter hypermethylation. From this epigenetically altered field, arise diverse polyps and cancers which show a range of molecular features. Despite a high serrated polyp count, only one-third of colorectal cancers demonstrate a BRAF V600E mutation, the molecular hallmark of the canonical serrated pathway, suggesting that though multiple serrated polyps act as a marker of an abnormal mucosa, the majority of CRC in these patients arise within lesions other than BRAF-mutated serrated polyps

    Literacy practices in the learning careers of childcare students

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    This paper draws from the Literacies for Learning in Further Education research project, funded through the Teaching and Learning Research Programme. Drawing on the empirical study of literacy practices in eight Childcare courses in Scotland and England, we seek to demonstrate that, integral to the learning careers of students are literacy careers through which their learning is mediated. In the process, by drawing upon the lens of literacy, we also challenge some of the common sense understandings of learning in childcare. In particular we suggest that the literacy practices of lower level courses can be more diverse than those of higher level courses, producing confusing literacy careers for the students involved. We also point to the complexity of the literacy careers in childcare, given that students are required to mediate different aspects of their experience through literacy. In particular there are the mediations made possible by the use of information technology and those entailed in relating work placements to classroom practice. We argue that students on vocational courses have complex literacy careers and that a literacies approach to learning helps to reveal this complexity

    Automatic differentiation evaluated as a tool for rotorcraft design and optimization

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    This paper investigates the use of automatic differentiation (AD) as a means for generating sensitivity analyses in rotorcraft design and optimization. This technique transforms an existing computer program into a new program that performs sensitivity analysis in addition to the original analysis. The original FORTRAN program calculates a set of dependent (output) variables from a set of independent (input) variables, the new FORTRAN program calculates the partial derivatives of the dependent variables with respect to the independent variables. The AD technique is a systematic implementation of the chain rule of differentiation, this method produces derivatives to machine accuracy at a cost that is comparable with that of finite-differencing methods. For this study, an analysis code that consists of the Langley-developed hover analysis HOVT, the comprehensive rotor analysis CAMRAD/JA, and associated preprocessors is processed through the AD preprocessor ADIFOR 2.0. The resulting derivatives are compared with derivatives obtained from finite-differencing techniques. The derivatives obtained with ADIFOR 2.0 are exact within machine accuracy and do not depend on the selection of step-size, as are the derivatives obtained with finite-differencing techniques

    BRAF Mutation in Colorectal Cancer

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    The BRAF mutant colorectal cancer subgroup is a small population with unique clinicopathological and molecular features. This subgroup has been associated with particularly poor prognosis and advanced disease. The poor response of these patients to available treatments has driven much of the effort in trialling combination targeted treatments involving BRAF and MEK inhibitors. Most recently, an observed survival benefit with intensive triplet chemotherapy agents would encourage its use as first-line treatment in suitable candidates given that few of these patients proceed to second- or third-line treatments
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