A record of Holocene climate change from lake geochemical analyses in southeastern Arabia

Lacustrine sediments from southeastern Arabia reveal variations in lake level corresponding to changes in the strength and duration of Indian Ocean Monsoon (IOM) summer rainfall and winter cyclonic rainfall. The late glacial/Holocene transition of the region was characterised by the development of mega-linear dunes. These dunes became stabilised and vegetated during the early Holocene and interdunal lakes formed in response to the incursion of the IOM at approximately 8500 cal yr BP with the development of C3 dominated savanna grasslands. The IOM weakened ca. 6000 cal yr BP with the onset of regional aridity, aeolian sedimentation and dune reactivation and accretion. Despite this reduction in precipitation, the take was maintained by winter dominated rainfall. There was a shift to drier adapted C4 grasslands across the dune field. Lake sediment geochemical analyses record precipitation minima at 8200, 5000 and 4200 cal yr BP that coincide with Bond events in the North Atlantic. A number of these events correspond with changes in cultural periods, suggesting that climate was a key mechanism affecting human occupation and exploitation of this region. (c) 2006 University of Washington. All rights reserved.

Poverty, migration and sex work: youth transitions in Ethiopia

Despite an emerging body of work on youth transitions, research has yet to explore the often unconventional routes to adulthood for young people marginalised through poverty. By drawing on interviews with 60 young commercial sex workers in Ethiopia, this paper explores the connections between poverty, migration and sex work and demonstrates that sex work provides a risky alternative, but often successful, path to independence for some rural-urban migrants. The paper concludes by offering recommendations for policies that seek to support young sex workers by enabling them to maintain their independence while seeking different employment.

Orphan worms and, homeless parasites enhance bilaterian diversity

Microscopic endoparasites belonging to the Phylum Myxozoa provide a striking example of how much there is still to be learned about the diversity of the Metazoa. Recent research on myxozoans has provided new insights into evolution within the Bilateria, revealing unparalleled levels of morphological simplification associated with parasitism, a home for an orphan worm, and a hypothesis of the endosymbiotic origin(s) for extrusible intracellular organelles in myxozoans and cnidarians. In addition, discovery of the source of a devastating disease of salmonid fish has enabled researchers to identify two ancient clades within the Myxozoa, and has exposed new mysteries concerning myxozoan life-cycle evolution and evolutionary diversification. This plethora of new insights exemplifies the fundamental value of studying obscure organisms.

A follow-up study of characteristics of young people that dropout and continue psychotherapy: service implications for a clinic in the community

Background: The paper reports the findings from a follow-up study of the factors that contribute to whether young people dropout or continue once-weekly psychotherapy at a voluntary sector psychotherapy service for young people aged 12 to 21 years. Method: The study uses data from an ongoing audit of the psychotherapy service that started in 1993; 882 young people were included in the study. Premature termination of treatment was defined as dropping out before the 21st session. Continuation in treatment was defined as remaining in therapy after 20 sessions. Measures and areas of interest used in the study include diagnostic measures, the Youth Self Report Form and Young Adult Self Report Form, demographic characteristics and treatment related information. Results: Young people who continued in treatment were more likely to be older, have anxieties about sexual and relationship issues and have higher scores on self-reported anxiety-depression. Young people who dropped out of treatment were more likely to be younger, have higher self-reported delinquency scores, have a diagnosis of hyperactivity-conduct disorder and be homeless. Conclusions: The study of treatment termination has demonstrated the value of service audit and has led to a significant change in clinical practice.

Disorder-specific functional abnormalities during sustained attention in youth with Attention Deficit Hyperactivity Disorder (ADHD) and with Autism

Attention Deficit Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD) are often comorbid and share behavioural-cognitive abnormalities in sustained attention. A key question is whether this shared cognitive phenotype is based on common or different underlying pathophysiologies. To elucidate this question, we compared 20 boys with ADHD to 20 age and IQ matched ASD and 20 healthy boys using functional magnetic resonance imaging (fMRI) during a parametrically modulated vigilance task with a progressively increasing load of sustained attention. ADHD and ASD boys had significantly reduced activation relative to controls in bilateral striato–thalamic regions, left dorsolateral prefrontal cortex (DLPFC) and superior parietal cortex. Both groups also displayed significantly increased precuneus activation relative to controls. Precuneus was negatively correlated with the DLPFC activation, and progressively more deactivated with increasing attention load in controls, but not patients, suggesting problems with deactivation of a task-related default mode network in both disorders. However, left DLPFC underactivation was significantly more pronounced in ADHD relative to ASD boys, which furthermore was associated with sustained performance measures that were only impaired in ADHD patients. ASD boys, on the other hand, had disorder-specific enhanced cerebellar activation relative to both ADHD and control boys, presumably reflecting compensation. The findings show that ADHD and ASD boys have both shared and disorder-specific abnormalities in brain function during sustained attention. Shared deficits were in fronto–striato–parietal activation and default mode suppression. Differences were a more severe DLPFC dysfunction in ADHD and a disorder-specific fronto–striato–cerebellar dysregulation in ASD.

Sibling caringscapes: time–space practices of caring within youth-headed households in Tanzania and Uganda

This paper investigates the time–space practices of young people caring for their siblings in youthheaded households affected by AIDS in Tanzania and Uganda. Based on qualitative exploratory research with young people heading households, their siblings, NGO workers and community members, the article develops the notion of sibling ‘caringscapes’ to analyse young people’s everyday practices and caring pathways through time and space. Participatory time-use data reveals that older siblings of both genders regularly undertake substantial caring tasks at the very high end of the caregiving continuum. Drawing on rhythmanalysis, the paper explores how young people negotiate emotional geographies and temporalities of caring. The competing rhythms of bodies, schooling, work and seasonal agricultural production can result in ‘arrhythmia’ and time scarcity, which has detrimental effects on young people’s health, education,future employment prospects and mobility. Young people’s lifecourse transitions are shaped to a large extent by their caring responsibilities, resulting in some young people remaining in a liminal position for considerable periods, unable to make ‘successful’ transitions to adulthood. Despite structural constraints,however, young people are able to exercise some autonomy over their caring pathways and lifecourse transitions. The research sheds light on the ways that individuals embody the practices, routines and rhythms of everyday life and exercise agency within highly restricted broader landscapes of care.