3,611 research outputs found

    Social experience during adolescence in female rats increases 50 kHz ultrasonic vocalizations in adulthood, without affecting anxiety-like behavior

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    Funding was provided by a University of St Andrews postgraduate studentship to MGE.Adolescents are highly motivated to engage in social interactions, and researchers have hypothesized that positive social relationships during adolescence can have long term, beneficial effects on stress reactivity and mental well‐being. Studies of laboratory rodents provide the opportunity to investigate the relationship between early social experiences and later behavioral and physiological responses to stressors. In this study, female Lister‐hooded rats (N = 12 per group) were either (a) provided with short, daily encounters (10 min/day) with a novel partner during mid‐adolescence (postnatal day 34–45; “social experience,” SE, subjects) or (b) underwent the same protocol with a familiar cagemate during mid‐adolescence (“control experience,” CE, subjects), or (c) were left undisturbed in the home cage (non‐handled “control,” C, subjects). When tested in adulthood, the groups did not differ in behavioral responses to novel environments (elevated plus maze, open field, and light‐dark box) or in behavioral and physiological (urinary corticosterone) responses to novel social partners. However, SE females emitted significantly more 50 kHz ultrasonic vocalizations than control subjects both before and after social separation from a familiar social partner, which is consistent with previous findings in male rats. Thus, enhanced adolescent social experience appears to have long‐term effects on vocal communication and could potentially modulate adult social relationships.PostprintPeer reviewe

    Pilot retrofit test of refrigerant R-134a for GDSCC

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    NASA has issued an interim policy requiring all of its Centers to eliminate consumption (purchase) of stratospheric ozone-depleting substances, including chlorofluorocarbons (CFC's), by 1995. Also, plans must be outlined for the eventual phase out of their usage. The greatest source of CFC consumption and usage at the Goldstone Deep Space Communications Complex is refrigerant R-12, which is used in many of the facility's air-conditioning systems. A pilot retrofit test shows that retrofitting R-12 air-conditioning systems with hydrofluorocarbon R-13a would be a workable means to comply with the R-12 portion of NASA's policy. Results indicate acceptable cost levels and nearly equivalent system performance

    Multi-wavelength INTEGRAL NEtwork (MINE) observations of the microquasar GRS 1915+105

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    We present the international collaboration MINE (Multi-lambda Integral NEtwork) aimed at conducting multi-wavelength observations of X-ray binaries and microquasars simultaneously with the INTEGRAL gamma-ray satellite. We will focus on the 2003 March-April campaign of observations of the peculiar microquasar GRS 1915+105 gathering radio, IR and X-ray data. The source was observed 3 times in the plateau state, before and after a major radio and X-ray flare. It showed strong steady optically thick radio emission corresponding to powerful compact jets resolved in the radio images, bright near-infrared emission, a strong QPO at 2.5 Hz in the X-rays and a power law dominated spectrum without cutoff in the 3-300 keV range. We compare the different observations, their multi-wavelength light curves, including JEM-X, ISGRI and SPI, and the parameters deduced from fitting the spectra obtained with these instruments on board INTEGRAL.Comment: 4 pages, 9 fig., Proc. of the 5th INTEGRAL Workshop (Feb. 16-20 2004), to be published by ES

    Simultaneous multi-wavelength observations of microquasars (the MINE collaboration)

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    We present the international collaboration MINE (Multi-lambda INTEGRAL NEtwork) aimed at conducting multi-wavelength observations of microquasars simultaneously with the INTEGRAL satellite. The first results on GRS 1915+105 are encouraging and those to come should help us to understand the physics of the accretion and ejection phenomena around a compact object.Comment: 2 p, 3 fig., proc. of the IAU Coll. 194, ``Compact Binaries in the Galaxy and Beyond'', Nov. 2003, La Paz, Mexico, to be published in the Conf. Series of Revista Mexicana de Astronomia y Astrofisica, Eds. G. Tovmassian & E. Sio

    In vivo localization at the cellular level of stilbene fluorescence induced by Plasmopara viticola in grapevine leaves

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    Accurate localization of phytoalexins is a key for better understanding their role. This work aims to localize stilbenes, the main phytoalexins of grapevine. The cellular localization of stilbene fluorescence induced by Plasmopara viticola, the agent of downy mildew, was determined in grapevine leaves of very susceptible, susceptible, and partially resistant genotypes during infection. Laser scanning confocal microscopy and microspectrofluorimetry were used to acquire UV-excited autofluorescence three-dimensional images and spectra of grapevine leaves 5–6 days after inoculation. This noninvasive technique of investigation in vivo was completed with in vitro spectrofluorimetric studies on pure stilbenes as their fluorescence is largely affected by the physicochemical environment in various leaf compartments. Viscosity was the major physicochemical factor influencing stilbene fluorescence intensity, modifying fluorescence yield by more than two orders of magnitude. Striking differences in the localization of stilbene fluorescence induced by P. viticola were observed between the different genotypes. All inoculated genotypes displayed stilbene fluorescence in cell walls of guard cells and periclinal cell walls of epidermal cells. Higher fluorescence intensity was observed in guard-cell walls than in any other compartment due to increased local viscosity. In addition stilbene fluorescence was found in epidermal cell vacuoles of the susceptible genotype and in the infected spongy parenchyma of the partially resistant genotype. The very susceptible genotype was devoid of fluorescence both in the epidermal vacuoles and the mesophyll. This strongly suggests that the resistance of grapevine leaves to P. viticola is correlated with the pattern of localization of induced stilbenes in host tissues

    Unequal relationships in high and low power distance societies: a comparative study of tutor - student role relations in Britain and China

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    This study investigated people's conceptions of an unequal role relationship in two different types of society: a high power distance society and a low power distance society. The study focuses on the role relationship of tutor and student. British and Chinese tutors and postgraduate students completed a questionnaire that probed their conceptions of degrees of power differential and social distance/closeness in this role relationship. ANOVA results yielded a significant nationality effect for both aspects. Chinese respondents judged the relationship to be closer and to have a greater power differential than did British respondents. Written comments on the questionnaire and interviews with 9 Chinese academics who had experienced both British and Chinese academic environments supported the statistical findings and indicated that there are fundamental ideological differences associated with the differing conceptions. The results are discussed in relation to Western and Asian concepts of leadership and differing perspectives on the compatibility/incompatibility of power and distance/closeness

    Controls on the composition and lability of dissolved organic matter in Siberia's Kolyma River basin

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    High-latitude northern rivers export globally significant quantities of dissolved organic carbon (DOC) to the Arctic Ocean. Climate change, and its associated impacts on hydrology and potential mobilization of ancient organic matter from permafrost, is likely to modify the flux, composition, and thus biogeochemical cycling and fate of exported DOC in the Arctic. This study examined DOC concentration and the composition of dissolved organic matter (DOM) across the hydrograph in Siberia's Kolyma River, with a particular focus on the spring freshet period when the majority of the annual DOC load is exported. The composition of DOM within the Kolyma basin was characterized using absorbance-derived measurements (absorbance coefficienta330, specific UV absorbance (SUVA254), and spectral slope ratio SR) and fluorescence spectroscopy (fluorescence index and excitation-emission matrices (EEMs)), including parallel factor analyses of EEMs. Increased surface runoff during the spring freshet led to DOM optical properties indicative of terrestrial soil inputs with high humic-like fluorescence, SUVA254, and low SRand fluorescence index (FI). Under-ice waters, in contrast, displayed opposing trends in optical properties representing less aromatic, lower molecular weight DOM. We demonstrate that substantial losses of DOC can occur via biological (∼30% over 28 days) and photochemical pathways (>29% over 14 days), particularly in samples collected during the spring freshet. The emerging view is therefore that of a more dynamic and labile carbon pool than previously thought, where DOM composition plays a fundamental role in controlling the fate and removal of DOC at a pan-Arctic scale

    Worse Postoperative Outcomes and Higher Reoperation in Smokers Compared to Nonsmokers for Arthroscopic Rotator Cuff Repair

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    Introduction: Smoking impairs healing potential and is a significant risk factor for complications following orthopaedic surgeries. The purpose of this study was to determine if a cohort of former or current smokers at time of surgery met the minimally clinical important difference (MCID) for Patient-Reported Outcomes Measurement Information System Upper Extremity (PROMIS-UE), Depression (PROMIS-D), and Pain Interference (PROMIS-PI) scores in comparison to nonsmokers. Methods: A retrospective review of patients who underwent rotator cuff repair was performed. Patients who completed preoperative and 6-month postoperative PROMIS scores were included. The MCID was calculated using a distribution technique with a threshold of 0.5 standard deviations above the mean. A cohort of nonsmokers was compared to current/former smokers in terms of clinical outcomes and PROMIS scores. Results: A total of 182 patients, 80 current/former smokers and 102 nonsmokers, were included. Smokers had significantly more massive-sized tears and more reoperations (16.3% vs 5.9%,P=0.02). No differences were found in change in PROMIS scores, proportion meeting MCID for PROMIS scores, and retear rate. In the sub-analysis, 74 current/former smokers were matched to 74 nonsmokers. Smokers had lower change in PROMIS-UE (8.6±9.8 vs 12.3±10.0,P=0.007) and PROMIS-PI (-9.1±8.5 vs -12.8±10.1,P=0.03) postoperatively. Fewer met MCID for PROMIS UE postoperatively (60.3% vs 82.4%,P=0.003) and more had reoperations (16.2% vs 4.1%,P=0.02). Conclusion: Smokers or former smokers demonstrated smaller improvements in function, pain scores, and were less likely to meet MCID for PROMIS-UE when compared to nonsmokers after arthroscopic rotator cuff repair. Smokers were more likely to undergo reoperations within 6 months

    Establishing Professional Intercultural Relations: Chinese Perceptions of Behavioural Success in a Sino-American Exchange Visit

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    This article examines the ways in which professionals from different countries handle first encounters when they wish to initiate and establish business/professional relations. The majority of research on business relations in intercultural contexts has so far focused on misunderstandings, face threats, and conflict. There has been comparatively little research into the initiation and establishment of relations from a positive perspective. This article addresses this lacuna by analysing how Chinese delegates built positive relations with American counterparts on a visit to the USA. Drawing on insights from the analysis, it proposes a conceptual framework for future research in this area

    A transient relativistic radio jet from Cygnus X-1

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    We report the first observation of a transient relativistic jet from the canonical black hole candidate, Cygnus X-1, obtained with the Multi-Element Radio-Linked Interferometer Network (MERLIN). The jet was observed in only one of six epochs of MERLIN imaging of the source during a phase of repeated X-ray spectral transitions in 2004 Jan--Feb, and this epoch corresponded to the softest 1.5-12 keV X-ray spectrum. With only a single epoch revealing the jet, we cannot formally constrain its velocity. Nevertheless, several lines of reasoning suggest that the jet was probably launched 0.5-4.0 days before this brightening, corresponding to projected velocities of 0.2c < v_app < 1.6c, and an intrinsic velocity of > 0.3c. We also report the occurrence of a major radio flare from Cyg X-1, reaching a flux density of ~120 mJy at 15 GHz, and yet not associated with any resolvable radio emission, despite a concerted effort with MERLIN. We discuss the resolved jet in terms of the recently proposed 'unified model' for the disc-jet coupling in black hole X-ray binaries, and tentatively identify the 'jet line' for Cyg X-1. The source is consistent with the model in the sense that a steady jet appears to persist initially when the X-ray spectrum starts softening, and that once the spectral softening is complete the core radio emission is suppressed and transient ejecta / shock observed. However, there are some anomalies, and Cyg X-1 clearly does not behave like a normal black hole transient in progressing to the canonical soft / thermal state once the ejection event has happened.Comment: Accepted for publication in MNRA
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