3,208 research outputs found

    Shock tunnel studies of scramjet phenomena

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    Commissioning of the new T4 shock tunnel at the University of Queensland implied that it was no longer necessary to focus the work of the research group about an annual test series conducted in the T3 shock tunnel in Canberra. Therefore, it has been possible to organize a group for work to proceed along lines such that particular personnel are associated with particular project areas. The format of this report consists of a series of reports on specific project areas, with a brief general introduction commenting on each report. The introduction is structured by project areas, with the title of the relevant report stated under the project area heading. The reports themselves follow in the order of the project area headings

    Prehistory of the British Isles: A tale of coming and going

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    It is now recognised that Britain has not always been geographically isolated from Europe and, for most of the last one million years, formed an extension of the northwest European landmass. During most of this time, Britain was accessible to migrating humans and animals, although climatic conditions varied greatly from Mediterranean-like through to glaciations and extreme cold, making Britain a difficult place to settle for any length of time. The oldest evidence for humans in Britain dates to between about 850,000 and 1 million years ago. Recovered lithic artefacts suggest that hominin species occupied and deserted the British Isles at least nine times. This article reviews the prehistory of the British Isles and presents the main sites and time periods

    Climate change adaptation planning and cross-sectoral policy coherence in southern Africa

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    The post-2015 development agenda requires policy coherence, where achievement of development goals in one sector does not undermine the achievement of the goals of another. It also recognises that cross-cutting issues like adaptation to climate change need to be mainstreamed across multiple sectors. This paper presents a policy analysis using the cases of Malawi, Tanzania and Zambia. It analyses the water management and agricultural strategies and approaches identified in a variety of policies and plans. These include national sector policies for water and agriculture, National Development Plans, and climate change policies and strategies, including National Adaptation Programmes of Action and the Intended Nationally Determined Contributions submitted prior to the 2015 United Nations Framework Convention on Climate Change Conference of the Parties. It assesses the extent to which policies are coherent with one another with regard to their treatment of climate change adaptation using Qualitative Document Analysis. Findings identify that sector policies show some degree of cross-thematic coherence, in particular around their acknowledgement of the importance to address disaster management of floods and droughts. However, policy statements are typified by a relative lack of recognition of the need to develop supporting instruments and strategies that address climate adaptation needs over longer timeframes. Climate change policies explicitly call for significant investment in adaptation from the international community. Where coherence between sector and climate policies and strategies is strongest, the more recent climate policies largely repackage existing sectoral policy statements. These findings can be understood in the context of the uncertainty of climate change impacts for the longer term (for which a wider variety of adaptations are identified), alongside more event-driven disaster management planning where the impacts are more immediate and obviously evident. This prioritisation is also linked to development needs and the short-term nature of political cycles and economic gain. For climate-resilient policy decision-making to make further headway, we argue that governments need to embrace cross-sectoral planning more pro- actively in order to foster greater policy coherence and to deliver more climate resilient agriculture and water management

    Reduced expression of brain cannabinoid receptor 1 (Cnr1) is coupled with an increased complementary micro-RNA (miR-26b) in a mouse model of fetal alcohol spectrum disorders

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    BACKGROUND: Prenatal alcohol exposure is known to result in fetal alcohol spectrum disorders, a continuum of physiological, behavioural, and cognitive phenotypes that include increased risk for anxiety and learning-associated disorders. Prenatal alcohol exposure results in life-long disorders that may manifest in part through the induction of long-term gene expression changes, potentially maintained through epigenetic mechanisms. FINDINGS: Here we report a decrease in the expression of Canabinoid receptor 1 (Cnr1) and an increase in the expression of the regulatory microRNA miR-26b in the brains of adult mice exposed to ethanol during neurodevelopment. Furthermore, we show that miR-26b has significant complementarity to the 3’-UTR of the Cnr1 transcript, giving it the potential to bind and reduce the level of Cnr1 expression. CONCLUSIONS: These findings elucidate a mechanism through which some genes show long-term altered expression following prenatal alcohol exposure, leading to persistent alterations to cognitive function and behavioural phenotypes observed in fetal alcohol spectrum disorders

    Sir Arthur Keith's Legacy: Re-discovering a lost collection of human fossils Quaternary International

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    In 2001, a collection of skeletal material was donated to the Natural History Museum, London, by the Royal College of Surgeons, London. It consisted of boxes discovered among the personal belongings of Sir Arthur Keith. This paper describes the work undertaken to identify and document the human skeletal material in the Keith Collection. The study identified the human fossils as having come from a number of excavations directed by Dorothy Garrod in the 1920s and 30s in Israel. The collection contains the long considered lost human skeletal collection from the type-site of the Natufian industry: Shukbah Cave. The majority of this material is of Natufian origin but contains a few Neanderthal specimens. A small amount of heavily fragmented bones associated with Skhul VII and IX were also found. The most remarkable of the re-discovered collection is the material from el-Wad and Kebara Caves. It was identified to be the missing material from the Middle and Upper Paleolithic levels briefly described in 1939 in The Stone Age of Mount Carmel by Theodore McCown and Sir Arthur Keith. These important fossils hold great potential to answer questions about the Middle to Upper Paleolithic transition in the Near East, and the emergence of anatomically modern humans

    Previous reproductive history and post-natal family planning among HIV-infected women in Ukraine

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    BACKGROUND: Ukraine has the highest antenatal HIV prevalence in Europe. The national prevention of mother-to-child transmission (MTCT) programme has reduced the MTCT rate, but less attention has been given to the prevention of unintended pregnancy among HIV-positive women. Our objectives were to describe the reproductive health, condom use and family planning (FP) practices of HIV-positive childbearing Ukrainian women and to identify factors associated with different methods of post-natal contraception. METHODS: HIV-infected childbearing women, diagnosed before or during pregnancy, were enrolled prospectively in a post-natal cohort study in four regional HIV/AIDS centres in Ukraine from December 2007. Logistic regression models were used to identify factors associated with post-natal FP practices. RESULTS: Data were available for 371 women enrolled by March 2009; 82% (n = 303) were married or cohabiting, 27% (97 of 363) reported a current HIV-negative sexual partner and 69% were diagnosed with HIV during their most recent pregnancy. Overall, 21% (75 of 349) of women were not using contraception post-natally (of whom 80% reported no current sexual activity), 50% (174 of 349) used condoms, 20% (74 of 349) relied solely/partially on coitus interruptus and 4% used hormonal methods or intrauterine device. Among married/cohabiting women, consistent use of condoms in the previous pregnancy [AOR 1.96 (95%CI 1.06–3.62)], having an HIV-positive partner [AOR 0.42 (0.20–0.87)], current sexual activity [AOR 4.53 (1.19–17.3)] and study site were significantly associated with post-natal condom use; 16% of those with HIV-negative partners did not use condoms. Risk factors for non-use of FP were lack of affordability [AOR 6.34 (1.73–23.2)] and inconsistent use of condoms in the previous pregnancy [AOR 7.25 (1.41–37.2)]. CONCLUSIONS: More than 40% of HIV-positive women in this population are at risk of unintended pregnancy and the one in six women in HIV-discordant couples not using barrier methods risk transmitting HIV to their partners. Our study results are limited by the observational nature of the data and the potential for both measured and unmeasured confounding

    A Computational Model of the Development of Separate Representations of Facial Identity and Expression in the Primate Visual System

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    Experimental studies have provided evidence that the visual processing areas of the primate brain represent facial identity and facial expression within different subpopulations of neurons. For example, in non-human primates there is evidence that cells within the inferior temporal gyrus (TE) respond primarily to facial identity, while cells within the superior temporal sulcus (STS) respond to facial expression. More recently, it has been found that the orbitofrontal cortex (OFC) of non-human primates contains some cells that respond exclusively to changes in facial identity, while other cells respond exclusively to facial expression. How might the primate visual system develop physically separate representations of facial identity and expression given that the visual system is always exposed to simultaneous combinations of facial identity and expression during learning? In this paper, a biologically plausible neural network model, VisNet, of the ventral visual pathway is trained on a set of carefully-designed cartoon faces with different identities and expressions. The VisNet model architecture is composed of a hierarchical series of four Self-Organising Maps (SOMs), with associative learning in the feedforward synaptic connections between successive layers. During learning, the network develops separate clusters of cells that respond exclusively to either facial identity or facial expression. We interpret the performance of the network in terms of the learning properties of SOMs, which are able to exploit the statistical indendependence between facial identity and expression

    A social-ecological systems approach is necessary to achieve land degradation neutrality

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    Viewing humans as drivers of change operating outside the natural environment is unhelpful for defining interventions that effectively manage change and complexity. Indeed, there is now broad agreement that en-vironmental governance needs to consider integrated social-ecological systems (SES) in order to tackle theworld’s grand challenges of land degradation. This requires a more differentiated, innovative approach that considers how changes in SES shape the functioning of land systems as a whole, and the synergies and trade-off these changes may produce. In this study, we identify and discuss some of the ways SES science and practice can inspire progress towards land degradation neutrality (LDN) outcomes in an integrated manner, through synthesis of literature and relevant documents related to the United Nations Convention to Combat Desertification(UNCCD). We do these by considering: (i) how LDN has been approached to date and the challenges likely to undermine progress towards achieving it; and (ii) an SES-based LDN approach relevant to the neutrality agenda, in particular, by describing how LDN might be thought of differently through an SES lens. We argue that an SES approach focusing on: (i)“people as part of nature”, not“people and nature”; and (ii) the frame of reference against which neutrality can be assessed across temporal and spatial dimensions, is necessary to both inform policy and guide actions of the different groups involved in avoiding and combating land degradation. Such an(integrated) approach adds a dimension (to achieving neutrality goals) not previously explored in sustainable land management and LDN research. Important next steps in operationalising the SES-based LDN approach involve empirical and field case studies, requiring interdisciplinary, mixed method technique
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