1,121 research outputs found

    Pituitary function tests in black patients with pseudocyesis

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    Pituitary function was evaluated in a group of 10 patients with pseudocyesis. One patient was postmenopausal; the remainder demonstrated normal basal prolactin, luteinising hormone (LH) and follicle-stimulating hormone (FSH) levels and also normal pituitary-adrenal, pituitary-thyroid axes. Oestradiol deficiency was present in 6 patients, while 2 patients demonstrated elevated serum progesterone values, suggestive of a luteal phase. Gonadotrophin-releasing hormone administration resulted in exaggerated stimulation of LH and FSH in 4 and 2 patients, respectively. Impaired growth hormone (GH) secretion was present in 6 patients after insulin-induced hypoglycaemia and L-dopa administration. GH impairment is probably a consequence of the oestrogen deficiency that commonly occurs in this condition. It thus appears that there are aberrations in specific pituitary hormone responses after provocation in pseudocyesis

    Disruption of State Estimation in the Human Lateral Cerebellum

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    The cerebellum has been proposed to be a crucial component in the state estimation process that combines information from motor efferent and sensory afferent signals to produce a representation of the current state of the motor system. Such a state estimate of the moving human arm would be expected to be used when the arm is rapidly and skillfully reaching to a target. We now report the effects of transcranial magnetic stimulation (TMS) over the ipsilateral cerebellum as healthy humans were made to interrupt a slow voluntary movement to rapidly reach towards a visually defined target. Errors in the initial direction and in the final finger position of this reach-to-target movement were significantly higher for cerebellar stimulation than they were in control conditions. The average directional errors in the cerebellar TMS condition were consistent with the reaching movements being planned and initiated from an estimated hand position that was 138 ms out of date. We suggest that these results demonstrate that the cerebellum is responsible for estimating the hand position over this time interval and that TMS disrupts this state estimate

    Aromatic antimony compounds. Transition metal complexes of 2,5-dimethylstibacyclopentadienyl

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    Hydrostannation of 2,4-hexadiyne with dibutyltin dihydride gave 1,1-dibutyl-2,5-dimethylstannole, which was converted to 2,5-dimethylstibacymantrene and to bis(2,5-dimethylstibacyclopentadienyl)iron.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23084/1/0000001.pd

    Older Adults’ Outdoor Walking and the Built Environment: Does Income Matter?

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    Background Our aim was to examine the association between Street Smart Walk Score® and self-reported outdoor walking among older Canadians, and to determine whether socioeconomic status modifies this association. Methods We linked objective walkability data with cross-sectional survey data from the Canadian Community Health Survey Healthy-Aging 2008–2009 Cycle for a sample of 1309 British Columbians aged ≥ 65 years. We examined associations between Street Smart Walk Score and meeting physical activity guidelines (≥150 min of moderate to vigorous activity/week) through self-reported outdoor walking using multivariable logistic regression, and tested for significant interactions with household income. Results A ten point higher Street Smart Walk Score was associated with a 17 % higher odds of meeting physical activity guidelines through walking outside (95 % CI: 1.07,1.27). In addition, older adults living in neighbourhoods categorised as Walker’s Paradise were over three times more likely to meet guidelines than those living in Car-dependent/Very car dependent neighbourhoods. We found no evidence that household income moderated the effect of Walk Score on walking outside. Conclusions Neighbourhood design may be one avenue whereby physical activity levels of older people can be enhanced through outdoor walking, with benefit across socioeconomic strata

    Theoretical and experimental approaches to understand morphogen gradients

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    Morphogen gradients, which specify different fates for cells in a direct concentration-dependent manner, are a highly influential framework in which pattern formation processes in developmental biology can be characterized. A common analysis approach is combining experimental and theoretical strategies, thereby fostering relevant data on the dynamics and transduction of gradients. The mechanisms of morphogen transport and conversion from graded information to binary responses are some of the topics on which these combined strategies have shed light. Herein, we review these data, emphasizing, on the one hand, how theoretical approaches have been helpful and, on the other hand, how these have been combined with experimental strategies. In addition, we discuss those cases in which gradient formation and gradient interpretation at the molecular and/or cellular level may influence each other within a mutual feedback loop. To understand this interplay and the features it yields, it becomes essential to take system-level approaches that combine experimental and theoretical strategies

    Assessing the impact of peat erosion on growing season CO2 fluxes by comparing erosional peat pans and surrounding vegetated haggs (article)

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    This is the author accepted manuscript. The final version is available from International Mire Conservation Group and International Peat Society via the DOI in this record.The research data supporting this publication are openly available from the University of Exeter's institutional repository at: https://doi.org/10.24378/exe.1143.Peatlands are recognised as an important but vulnerable ecological resource. Understanding the effects of existing damage, in this case erosion, enables more informed land management decisions to be made. Over the growing seasons of 2013 and 2014 photosynthesis and ecosystem respiration were measured using closed chamber techniques within vegetated haggs and erosional peat pans in Dartmoor National Park, southwest England. Below-ground total and heterotrophic respiration were measured and autotrophic respiration estimated from the vegetated haggs. The mean water table was significantly higher in the peat pans than in the vegetated haggs; because of this, and the switching from submerged to dry peat, there were differences in vegetation composition, photosynthesis and ecosystem respiration. In the peat pans photosynthetic CO2 uptake and ecosystem respiration were greater than in the vegetated haggs and strongly dependent on the depth to water table (r2>0.78, p<0.001). Whilst in the vegetated haggs, photosynthesis and ecosystem respiration had the strongest relationships with normalised difference vegetation index (NDVI) (r2=0.82, p<0.001) and soil temperature at 15 cm depth (r2=0.77, p=0.001). Autotrophic and total below-ground respiration in the vegetated haggs varied with soil temperature; heterotrophic respiration increased as water tables fell. An empirically derived net ecosystem model estimated that over the two growing seasons both the vegetated haggs (29 and 20 gC m 2; 95 % confidence intervals of -570 to 762 and -873 to 1105 gC m-2) and the peat pans (7 and 8 gC m 2; 95 % confidence intervals of -147 to 465 and -136 to 436 gC m 2) were most likely net CO2 sources. This study suggests that not only the visibly degraded bare peat pans but also the surrounding vegetated haggs are losing carbon to the atmosphere, particularly during warmer and drier conditions, highlighting a need for ecohydrological restoration.MomentaSouth West Water (SWW)Dartmoor National Park Authorit

    New Directions in Conservation for the National Wildlife Refuge System

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    The National Wildlife Refuge System Improvement Act of 1997 includes the nation’s broadest statutory commitment to ecosystem protection: to “ensure that the biological integrity, diversity, and environmental health of the system are maintained.” The act also directs the US Fish and Wildlife Service (FWS) to expand the scope of conservation monitoring, assessment, and management beyond refuge boundaries to encompass surrounding landscapes. The act thus gives the FWS a leadership role in developing research and management partnerships with other agencies, organizations, and neighboring landowners. Increasing research capacity and scientific expertise, and strengthening institutional resolve to limit activities that impede the attainment of this directive, are challenges for the FWS. Success requires reexamination of existing priorities, refocused training, the acquisition of new funding and technical expertise, and creative application of those new skills to meet the law’s broad mandat

    The SOAR Optical Imager

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    The SOAR Optical Imager (SOI) is the commissioning instrument for the 4.2-m SOAR telescope, which is sited on Cerro Pachón, and due for first light in April 2003. It is being built at Cerro Tololo Inter-American Observatory, and is one of a suite of first-light instruments being provided by the four SOAR partners (NOAO, Brazil, University of North Carolina, Michigan State University). The instrument is designed to produce precision photometry and to fully exploit the expected superb image quality of the SOAR telescope, over a 6x6 arcmin field. Design goals include maintaining high throughput down to the atmospheric cut-off, and close reproduction of photometric passbands throughout 310-1050nm. The focal plane consists of a two-CCD mosaic of 2Kx4K Lincoln Labs CCDs, following an atmospheric dispersion corrector, focal reducer, and tip-tilt sensor. Control and data handling are within the LabVIEW-Linux environment used throughout the SOAR Project
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