143 research outputs found

    Longitudinal rates of self-reported delinquency of at-risk and not at-risk Western Australian high school students

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    Two hundred and forty nine 12 to 13 year old at risk and not at risk male and female high school students randomly selected from five high schools in the Perth metropolitan area of Western Australia provided self-reported delinquency data for three consecutive years. A multivariate analysis of variance revealed at risk students self-reported significantly more involvement in delinquency at the first data collection point than their not at risk counterparts. Male 12-13 year olds self-reported significantly more involvement in car related crimes, assault, rule infractions, and vandalism compared to their female peers. For some delinquent activities there were significant increases in involvement over time (Motor Vehicle, Drugs, and Public Disorder Offences) while for others (Theft, Rule Infractions, and Vandalism) this was not the case. In the majority of categories of delinquency at risk students self-reported significantly higher rates of involvement

    Childhood loneliness as a predictor of adolescent depressive symptoms: an 8-year longitudinal study

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    Childhood loneliness is characterised by children’s perceived dissatisfaction with aspects of their social relationships. This 8-year prospective study investigates whether loneliness in childhood predicts depressive symptoms in adolescence, controlling for early childhood indicators of emotional problems and a sociometric measure of peer social preference. 296 children were tested in the infant years of primary school (T1 5 years of age), in the upper primary school (T2 9 years of age) and in secondary school (T3 13 years of age). At T1, children completed the loneliness assessment and sociometric interview. Their teachers completed externalisation and internalisation rating scales for each child. At T2, children completed a loneliness assessment, a measure of depressive symptoms, and the sociometric interview. At T3, children completed the depressive symptom assessment. An SEM analysis showed that depressive symptoms in early adolescence (age 13) were predicted by reports of depressive symptoms at age 8, which were themselves predicted by internalisation in the infant school (5 years). The interactive effect of loneliness at 5 and 9, indicative of prolonged loneliness in childhood, also predicted depressive symptoms at age 13. Parent and peer-related loneliness at age 5 and 9, peer acceptance variables, and duration of parent loneliness did not predict depression. Our results suggest that enduring peer-related loneliness during childhood constitutes an interpersonal stressor that predisposes children to adolescent depressive symptoms. Possible mediators are discussed

    A sad tale: has the small mussel Idas argenteus lost its symbionts?

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    Idas argenteus (Bivalvia: Mytilidae) belongs to a genus of mussels that are often associated with sunken wood and vertebrate bones in the deep sea. By contrast to other species currently included within the genus Idas and other related genera, such as Bathymodiolus, I. argenteus was documented to lack chemosynthetic symbionts bacterial symbionts in its gills. In the present study, new specimens are assigned to I. argenteus based on shell and soft parts analysis. Molecular data confirm the absence or low abundance of symbionts. Phylogeny based on five genes indicates that the symbiont-bearing I. washingtonius is the closest relative of I. argenteus. Symbiosis loss or extreme reduction is thus inferred to have occurred subsequent to the speciation event, 11–13 Mya. This is the first report of a loss of symbiosis within the clade of deep-sea chemosynthetic mussels

    Delinquency and reputational orientations of adolescent at-risk and not-at-risk males and females

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    This research investigated differences in delinquent activities and the reputational orientations of at-risk and not-at-risk male and female adolescents. Initially, we sought to establish that adolescent males and females differed in these respects. This was found to be the case: males (n = 722) scored significantly higher than females (n = 738) on seven self-reported delinquency variables and on eight reputation enhancement variables pertaining to social deviance, non-conforming reputation, and power/evaluation private identity. When a sample of 31 at-risk females was subsequently pair-wise age matched with 31 not-at-risk females, at-risk females scored significantly higher on all delinquency variables other than school misdemeanors. These at-risk females also scored significantly higher on four reputation enhancement variables relating to social deviance and non-conformity. Given that at-risk females did not differ from their not-at-risk counterparts in level of involvement in school misdemeanors, we sought to determine whether this was also the case for at-risk and not-at-risk males. An age-matched sample of 91 pairs revealed that at-risk males reported significantly higher involvement than not-at-risk males in all aspects of delinquency, including school misdemeanors. They also sought a more non-conforming reputation. To explore the relationships between delinquency and reputation enhancement, a canonical correlation analysis was performed. All findings are discussed in the light of reputation enhancement theory. © 2008 Taylor & Franci

    Challenges Using Extrapolated Family-level Macroinvertebrate Metrics in Moderately Disturbed Tropical Streams: a Case-study From Belize

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    Family-level biotic metrics were originally designed to rapidly assess gross organic pollution effects, but came to be regarded as general measures of stream degradation. Improvements in water quality in developed countries have reignited debate about the limitations of family-level taxonomy to detect subtle change, and is resulting in a shift back towards generic and species-level analysis to assess smaller effects. Although the scale of pollution characterizing past condition of streams in developed countries persists in many developing regions, some areas are still considered to be only moderately disturbed. We sampled streams in Belize to investigate the ability of family-level macroinvertebrate metrics to detect change in stream catchments where less than 30% of forest had been cleared. Where disturbance did not co-vary with natural gradients of change, and in areas characterized by low intensity activities, none of the metrics tested detected significant change, despite evidence of environmental impacts. We highlight the need for further research to clarify the response of metrics to disturbance over a broader study area that allows replication for confounding sources of natural variation. We also recommend research to develop more detailed understanding of the taxonomy and ecology of Neotropical macroinvertebrates to improve the robustness of metric use

    Ecology and Biogeography of Free-Living Nematodes Associated with Chemosynthetic Environments in the Deep Sea: A Review

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    Background: Here, insight is provided into the present knowledge on free-living nematodes associated with chemosynthetic environments in the deep sea. It was investigated if the same trends of high standing stock, low diversity, and the dominance of a specialized fauna, as observed for macro-invertebrates, are also present in the nematodes in both vents and seeps. Methodology: This review is based on existing literature, in combination with integrated analysis of datasets, obtained through the Census of Marine Life program on Biogeography of Deep-Water Chemosynthetic Ecosystems (ChEss). Findings: Nematodes are often thriving in the sulphidic sediments of deep cold seeps, with standing stock values ocassionaly exceeding largely the numbers at background sites. Vents seem not characterized by elevated densities. Both chemosynthetic driven ecosystems are showing low nematode diversity, and high dominance of single species. Genera richness seems inversely correlated to vent and seep fluid emissions, associated with distinct habitat types. Deep-sea cold seeps and hydrothermal vents are, however, highly dissimilar in terms of community composition and dominant taxa. There is no unique affinity of particular nematode taxa with seeps or vents. Conclusions: It seems that shallow water relatives, rather than typical deep-sea taxa, have successfully colonized the reduced sediments of seeps at large water depth. For vents, the taxonomic similarity with adjacent regular sediments is much higher, supporting rather the importance of local adaptation, than that of long distance distribution. Likely the ephemeral nature of vents, its long distance offshore and the absence of pelagic transport mechanisms, have prevented so far the establishment of a successful and typical vent nematode fauna. Some future perspectives in meiofauna research are provided in order to get a more integrated picture of vent and seep biological processes, including all components of the marine ecosystem
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