354 research outputs found

    LARGE-EDDY SIMULATION OF TURBULENT PLANE COUETTE FLOW

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    The purpose of this study was to explore the central core region of a plane turbulent Cou- ette flow by means of large-eddy simulations. First it was demonstrated how accurately a low Reynolds number flow could be simulated. After having verified the reliability of the LES approach. simulations were performed at a substantially higher Re. It was observed that the mean velocity exhibited a practically linear variation in the core region. The extent of the core increased with Re, whereas the slope of the mean velocity profile was significantly reduced

    SDL - The IoT Language

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    Interconnected smart devices constitute a large and rapidly growing element of the contemporary Internet. A smart thing can be as simple as a web-enabled device that collects and transmits sensor data to a repository for analysis, or as complex as a web-enabled system to monitor and manage a smart home. Smart things present marvellous opportunities, but when they participate in complex systems, they challenge our ability to manage risk and ensure reliability. SDL, the ITU Standard Specification and Description Language, provides many advantages for modelling and simulating communicating agents – such as smart things – before they are deployed. The potential for SDL to enhance reliability and safety is explored with respect to existing smart things below. But SDL must advance if it is to become the language of choice for developing the next generation of smart things. In particular, it must target emerging IoT platforms, it must support simulation of interactions between pre-existing smart things and new smart things, and it must facilitate deployment of large numbers of similar things. Moreover, awareness of the potential benefits of SDL must be raised if those benefits are to be realized in the current and future Internet of Things.Peer ReviewedPostprint (published version

    Influence of Agronomic and Climatic Factors on Fusarium Infestation and Mycotoxin Contamination of Cereals in Norway

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    A total of 602 samples of organically and conventionally grown barley, oats and wheat was collected at grain harvest during 2002–2004 in Norway. Organic and conventional samples were comparable pairs regarding cereal species, growing site and harvest time, and were analysed for Fusarium mould and mycotoxins. Agronomic and climatic factors explained 10–30% of the variation in Fusarium species and mycotoxins. Significantly lower Fusarium infestation and concentrations of important mycotoxins were found in the organic cereals. The mycotoxins deoxynivalenol (DON) and HT-2 toxin (HT-2) constitute the main risk for human and animal health in Norwegian cereals. The impacts of various agronomic and climatic factors on DON and HT-2 as well as on their main producers F. graminearum and F. langsethiae and on total Fusarium were tested by multivariate statistics. Crop rotation with non-cereals was found to reduce all investigated characteristics significantly – mycotoxin concentrations as well as various Fusarium infestations. No use of mineral fertilisers and herbicides was also found to decrease F. graminearum, whereas lodged fields increased the occurrence of this species. No use of herbicides was also found to decrease F. langsethiae, but for this species the occurrence was lower in lodged fields. Total Fusarium infestation was decreased with no use of fungicides or mineral fertilisers, and with crop rotation, as well as by using herbicides and increased by lodged fields. Clay and to some extent silty soils seemed to reduce F. graminearum in comparison with sandy soils. Concerning climate factors, low temperature before grain harvest was found to increase DON; and high air humidity before harvest to increase HT-2. F. graminearum was negatively correlated with precipitation in July but correlated with air humidity before harvest. F. langsethiae was correlated with temperature in July. Total Fusarium increased with increasing precipitation in July. Organic cereal farmers have fewer cereal intense rotations than conventional farmers. Further, organic farmers do not apply mineral fertiliser or pesticides (fungicides, herbicides or insecticides), and have less problem with lodged fields. The study showed that these agronomic factors were related to the infestation of Fusarium species and the concentration of mycotoxins. Hence, it is reasonable to conclude that farming system (organic versus conventional) impacts Fusarium infestation, and that organic management tends to reduce Fusarium and mycotoxins. However, Fusarium infestation and mycotoxin concentrations may be influenced by a range of factors not studied here, such as local topography and more local climate, as well as cereal species and variety

    Wandering behaviour prevents inter and intra oceanic speciation in a coastal pelagic fish

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    Small pelagic fishes have the ability to disperse over long distances and may present complex evolutionary histories. Here, Old World Anchovies (OWA) were used as a model system to understand genetic patterns and connectivity of fish between the Atlantic and Pacific basins. We surveyed 16 locations worldwide using mtDNA and 8 microsatellite loci for genetic parameters, and mtDNA (cyt b; 16S) and nuclear (RAG1; RAG2) regions for dating major lineage-splitting events within Engraulidae family. The OWA genetic divergences (0-0.4%) are compatible with intra-specific divergence, showing evidence of both ancient and contemporary admixture between the Pacific and Atlantic populations, enhanced by high asymmetrical migration from the Pacific to the Atlantic. The estimated divergence between Atlantic and Pacific anchovies (0.67 [0.53-0.80] Ma) matches a severe drop of sea temperature during the Gunz glacial stage of the Pleistocene. Our results support an alternative evolutionary scenario for the OWA, suggesting a coastal migration along south Asia, Middle East and eastern Africa continental platforms, followed by the colonization of the Atlantic via the Cape of the Good Hope.Portuguese Foundation for Science & Technology (FCT) [SFRH/BD/36600/2007]; FCT [UID/MAR/04292/2013, SFRH/BPD/65830/2009]; FCT strategic plan [UID/Multi/04326/2013]info:eu-repo/semantics/publishedVersio

    Lone mothers’ time allocations: Choices and satisfactions

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    This paper uses the 2006 Australian Time Use Survey to examine theallocation of time to personal care, employment-related activities, homeduties, leisure and child care of lone mothers, in comparison to the timeallocations of single women, women in childless couples and partneredmothers. Both primary and secondary time allocations are considered. Thesatisfactions that women report concerning their current time allocations arealso analysed. The time use and satisfaction data are described using bothtabulations and multiple regression methods. Lone mothers are shown tohave similar time allocations as the other types of households, even thoughthey have different financial and time resources. This raises the concernthat lone mothers’ desire or need to maintain such time allocations maylead to task overload. Consistent with this, lone mothers are found to beless satisfied with the way they allocate their time than single women andpartnered mothers. The tensions associated with time use among lonemothers discussed in the literature are real, and important

    Sea ice breakup and marine melt of a retreating tidewater outlet glacier in northeast Greenland (81°N)

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    Rising temperatures in the Arctic cause accelerated mass loss from the Greenland Ice Sheet and reduced sea ice cover. Tidewater outlet glaciers represent direct connections between glaciers and the ocean where melt rates at the ice-ocean interface are influenced by ocean temperature and circulation. However, few measurements exist near outlet glaciers from the northern coast towards the Arctic Ocean that has remained nearly permanently ice covered. Here we present hydrographic measurements along the terminus of a major retreating tidewater outlet glacier from Flade Isblink Ice Cap. We show that the region is characterized by a relatively large change of the seasonal freshwater content, corresponding to ~2 m of freshwater, and that solar heating during the short open water period results in surface layer temperatures above 1 °C. Observations of temperature and salinity supported that the outlet glacier is a floating ice shelf with near-glacial subsurface temperatures at the freezing point. Melting from the surface layer significantly influenced the ice foot morphology of the glacier terminus. Hence, melting of the tidewater outlet glacier was found to be critically dependent on the retreat of sea ice adjacent to the terminus and the duration of open water

    Herbal medicine use during pregnancy in a group of Australian women

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    BACKGROUND: There are limited data on the extent of women's use of herbal medicines during pregnancy, despite the fact that knowledge of the potential benefits or harms of many of these products is sparse, particularly with respect to their use in pregnancy. We aimed to measure the prevalence of herbal medicine use in a group of pregnant women attending a public tertiary maternity hospital in Melbourne, Australia. Secondary aims were to explore why women took the herbal medicine, where they received advice, what form the supplements took and if they perceived the supplements to be helpful. METHODS: Consecutive pregnant women were approached in the antenatal clinic and the birth centre at around 36–38 weeks gestation. A questionnaire was developed and self-administered in English, as well as being translated into the four most common languages of women attending the hospital: Cantonese, Vietnamese, Turkish and Arabic. Back translation into English was undertaken by different professional translators to verify accuracy of both words and concepts. Data collected included demographic information, model of pregnancy care and herbal supplement use. Descriptive statistics were used initially, with stratified and regression analysis to compare sub-groups. RESULTS: Of 705 eligible women, 588 (83%) agreed to participate. Of these, 88 (15%) completed the questionnaire in a language other than English. Thirty-six percent of women took at least one herbal supplement during the current pregnancy. The most common supplements taken were raspberry leaf (14%), ginger (12%) and chamomile (11%). Women were more likely to take herbal supplements if they were older, tertiary educated, English speaking, non-smokers and primiparous. CONCLUSION: Use of herbal supplements in pregnancy is likely to be relatively high and it is important to ascertain what supplements (if any) women are taking. Pregnancy care providers should be aware of the common herbal supplements used by women, and of the evidence regarding potential benefits or harm
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