1,062 research outputs found

    Evidence for the formation of supplementary corpora lutea in the pregnant and pseudopregnant rat

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    In a series of experiments investigating a possible post-coitum contraceptive, it was observed that the numbers of corpora lutea (CL) of pregnant Sprague-Dawley (CD) rats were greater than in cyclic, unmated control females (p<0.001). The ontogeny of these supplementary CL (SCL) was established by the recording the mean number of CL in pregnant Sprague-Dawley rats on days 1 to 9 post-coitum (day 1 being the first day post-coitum) using the gross phological dissection of the ovary. Compared to cyclic controls, an initial significant increase in mean CL numbers was recorded on day 1 post-coitum (p<0.05) with a further significant increase between days 5 and 7 (p<0.001). This phenomena was neither Sprague-Dawley strain, nor pregnancy specific, as a similar increase was also recorded for Wistar rats between days 4 and 7 postcoitum and identical increases in mean CL numbers were recorded in pseudopregnant rats of both strains. Histological studies of ovarian tissue confirmed the presence of newly formed CL on day 5 and 6 post-coitum and an absence of entrapped ova; follicular development was also present in early pregnancy with Graafian follicles evident on day 4 post-coitum. Plasma progesterone determinations revealed no increase in circulating progesterone as a result of SCL formation in either pregnant or pseudopregnant rats. Supplementary ovulations may be initiated by the preimplantation surge of oestrogen, on day 4 post-coitum, as treatment with the anti-oestrogen. Tamoxifen, inhibits their formation. Investigations into the presence of an appropriately-timed preovulatory surge of gonadotrophins in the early stages of pregnancy however, proved inconclusive. Supplementary ovulation occurs therefore between day 4 and 7 post-coitum in both pregnant and pseudopregnant Wistar and Sprague-Dawley rats, probably initiated by a consistent physiological event. This phenomena therefore obviously has an impact on the estimation of embryo mortality studies in this species

    Development of a color display capability

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    Color display capabilities for digital computer

    An update on the potential for male contraception : emerging options

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    The human population continues to grow and is estimated to rise to 10.1 billion by the end of the century. Therefore, there is still an unmet need for safe and highly effective contraceptive options for both men and women. Current options available to men include withdrawal, condoms, and vasectomy. Methods in development fall into two categories: hormonal and nonhormonal. This review will provide an overview of the testosterone combinations and immunocontraception of hormonal targets. Nonhormonal immunocontraception of sperm proteins will also be examined, together with the use of agents to disrupt other sperm-associated targets and pathways. The categories focused on include epididymal proteins, testicular kinases, epigenetic reader proteins, opioids, lonidamine derivatives, retinoic acid, microRNAs associated with spermatogenesis, and plant extracts. Considering these developments, the number of options available to men is likely to increase in the near future

    Growth and yield responses to amending the sugarcane monoculture: interactions between break history and nitrogen fertiliser

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    Experiments were established in the Burdekin Irrigation Area in North Queensland, Australia, to measure whether yield improvements from breaking the sugarcane monoculture or fumigating the soil could be modified by the application of different rates of nitrogen (N) fertiliser. Experiments were conducted in consecutive crop cycles (phase 1, planted 1998; phase 2, planted 2001) using the variety Q117, with the interaction between N applications and rotation histories discussed for the two plant crops. Histories consisted of alternate crop, bare fallow or mixed grass-legume pastures for periods of 42-66 months, compared with continuous cane as plough-out replant without (PORP) or with (PORP-F) soil fumigation. The N strategies involved combinations of N rates (0-180kgN/ha) and application times (at planting, 90 days after planting (DAP) or split between these times) in phase 1 and N rates (0-300kgN/ha) in phase 2. Histories had differing effects on N available to the cane crop and hence on response to N fertiliser. Some combinations of history and N rate were N-limited and strong linear relationships between biomass production or cane yield and crop N content could be developed. Critical N contents for biomass production (R2≤0.93) and fresh-weight cane yield (R2≤0.88) were 1.42 and 0.57kgN/t, respectively. Application of N fertiliser was shown to have significant impacts on both tiller addition and the retention of tillers to produce harvestable stalks. However, the application of fertiliser N had limited (phase 1) or no (phase 2) capacity to provide the quantum of yield response in soil health benefits associated with breaking the sugarcane monoculture. Increasing N application rates above that required to optimise crop yield resulted in significant decreases in sugar content of cane and thus lower sugar yields. Yield increases solely from improved soil health (i.e. exclusive of N response) constituted advantages averaging 15% (phase 1) to 20% (phase 2) compared with PORP. These effects were manifest early in the establishment of primary shoots in the plant crops, although the longevity of these benefits was limited. Replanting cane after a 3-year crop cycle (plant, 1st and 2nd ratoon) on land that had been under pasture, crop, bare fallow or PORP-F histories (phase 2, cycle 2) showed carryover effects of histories on N availability and fertiliser N responsiveness, but limited yield impacts attributable to residual soil health benefits. These results reinforce the importance of crop rotation during breaks between sugarcane cycles to maintain soil health and improve crop productivity

    How do older people describe their sensory experiences of the natural world? a systematic review of the qualitative evidence

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    This is the final version of the article. Available from the publisher via the DOI in this record.BACKGROUND: Despite the increased scholarly interest in the senses and sensory experiences, the topic of older people's sensory engagement with nature is currently under researched. This paper reviews and synthesises qualitative research evidence about how older people, including those living with dementia, describe their sensory engagement with the natural world. METHODS: Ten databases were searched from 1990 to September 2014: MEDLINE (Ovid), MEDLINE-in-Process (Ovid), PsycINFO (Ovid), CINAHL (EBSCO), GreenFILE (EBSCO), ProQuest Sociology, ASSIA (ProQuest), International Bibliography of the Social Sciences (ProQuest); HMIC (Ovid); Social Policy and Practice (Ovid). Forward and backward citation chasing of included articles was conducted; 20 organizations were contacted to identify unpublished reports. Screening was undertaken independently by two reviewers. RESULTS: Twenty seven studies were included. Thematic analysis revealed that descriptions of sensory experiences are encompassed within six themes: descriptions from 'the window'; sensory descriptions that emphasise vision; descriptions of 'being in nature'; descriptions of 'doing in nature'; barriers to sensory engagement; and meanings of being and doing in nature. CONCLUSIONS: Older people derive considerable pleasure and enjoyment from viewing nature, being and doing in nature which, in turn has a positive impact on their wellbeing and quality of life. Future research could usefully explore how sensory engagement with nature could be used to stimulate reminiscences of places and people, and evoke past sensory experiences to enrich everyday life and maintain a sense of self. The protocol was registered with PROSPERO ( CRD42015020736 ).The research for this systematic review was supported by the European Centre for Environment and Human Health which is in part financed by the European Regional Development Fund Programme 2007 to 2013 and European Social Fund Convergence for Cornwall and Isles of Scilly. RG is partially supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care (CLAHRC) for the South West Peninsula

    What are the health and well-being impacts of community gardening for adults and children: a mixed method systematic review protocol

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    Background Community gardening is defined by its shared nature; gardeners work collectively to manage a garden for shared benefit. Although communal gardening activities, and recognition of their perceived benefits have a long history, it is in recent years that interest has developed in assessing the potential of the approach to address many of the threats to health and wellbeing faced by global populations. Community gardening may address chronic and non-communicable disease through the provision of opportunities for physical activity, improved nutrition and reduced stress. Participation in the gardening activities may improve wellbeing through increased social contact, culturally valued activities and mitigation of food poverty. The benefits of community gardening are argued to extend beyond the participants themselves through more coherent and cohesive communities, improved physical environments and the sharing of the products of the labour. While there are many claims made and an emerging body of research, no previous systematic review has sought to identify and synthesise the evidence in a global context. Methods The objectives of the mixed method systematic review are to understand the health and wellbeing impacts of active participation in community gardening. Both quantitative and qualitative evidence will be sought using a broad and diverse search strategy to address the four review questions: 1) does active involvement in community gardening lead to improved health or wellbeing; 2) if so, how does active involvement in community gardening affect health and wellbeing; 3) are there different impacts for different population groups (for instance according to age, socio-economic status or sex); and 4) do different types of community gardening (for example producing vegetables or a flower garden) or in different contexts have different types of impacts? A theoretical framework, informed by an initial theory of change model, will illustrate the outcomes of participation and any mechanisms of action (i.e. how such impacts are achieved). The synthesis will be sensitive to factors which may affect the impacts, such as the context of the activities, the demographics of participants, and the implementation and specifics of the community gardening interventions.European Regional Development Fund Programme 2007 to 2013Social Fund Convergence Programme for Cornwall and the Isles of Scill

    Affine configurations and pure braids

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    We show that the fundamental group of the space of ordered affine-equivalent configurations of at least five points in the real plane is isomorphic to the pure braid group modulo its centre. In the case of four points this fundamental group is free with eleven generators.Comment: 5 pages, 1 figure, final version; to appear in Discrete & Computational Geometry, available from the publishers at http://www.springerlink.com/content/384516n7q24811ph
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