1,906 research outputs found

    Higher sociability leads to lower reproductive success in female kangaroos: Sociability and fitness in kangaroos

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    In social mammals, social integration is generally assumed to improve females’ reproductive success. Most species demonstrating this relationship exhibit complex forms of social bonds and interactions. However, female eastern grey kangaroos (Macropus giganteus) exhibit differentiated social relationships, yet do not appear to cooperate directly. It is unclear what the fitness consequences of such sociability could be in species that do not exhibit obvious forms of cooperation. Using 4 years of life history, spatial and social data from a wild population of approximately 200 individually recognizable female eastern grey kangaroos, we tested whether higher levels of sociability are associated with greater reproductive success. Contrary to expectations, we found that the size of a female’s social network, her numbers of preferential associations with other females and her group sizes all negatively influenced her reproductive success. These factors influenced the survival of dependent young that had left the pouch rather than those that were still in the pouch. We also show that primiparous females (first-time breeders) were less likely to have surviving young. Our findings suggest that social bonds are not always beneficial for reproductive success in group-living species, and that female kangaroos may experience trade-offs between successfully rearing young and maintaining affiliative relationships

    Higher sociability leads to lower reproductive success in female kangaroos

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    In social mammals, social integration is generally assumed to improve females' reproductive success. Most species demonstrating this relationship exhibit complex forms of social bonds and interactions. However, female eastern grey kangaroos (Macropus giganteus) exhibit differentiated social relationships, yet do not appear to cooperate directly. It is unclear what the fitness consequences of such sociability could be in species that do not exhibit obvious forms of cooperation. Using 4 years of life history, spatial and social data from a wild population of approximately 200 individually recognizable female eastern grey kangaroos, we tested whether higher levels of sociability are associated with greater reproductive success. Contrary to expectations, we found that the size of a female's social network, her numbers of preferential associations with other females and her group sizes all negatively influenced her reproductive success. These factors influenced the survival of dependent young that had left the pouch rather than those that were still in the pouch. We also show that primiparous females (first-time breeders) were less likely to have surviving young. Our findings suggest that social bonds are not always beneficial for reproductive success in group-living species, and that female kangaroos may experience trade-offs between successfully rearing young and maintaining affiliative relationships

    Levosimendan for the prevention of acute organ dysfunction in sepsis

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    BACKGROUND Levosimendan is a calcium-sensitizing drug with inotropic and other properties that may improve outcomes in patients with sepsis. METHODS We conducted a double-blind, randomized clinical trial to investigate whether levosimendan reduces the severity of organ dysfunction in adults with sepsis. Patients were randomly assigned to receive a blinded infusion of levosimendan (at a dose of 0.05 to 0.2 μg per kilogram of body weight per minute) for 24 hours or placebo in addition to standard care. The primary outcome was the mean daily Sequential Organ Failure Assessment (SOFA) score in the intensive care unit up to day 28 (scores for each of five systems range from 0 to 4, with higher scores indicating more severe dysfunction; maximum score, 20). Secondary outcomes included 28-day mortality, time to weaning from mechanical ventilation, and adverse events. RESULTS The trial recruited 516 patients; 259 were assigned to receive levosimendan and 257 to receive placebo. There was no significant difference in the mean (±SD) SOFA score between the levosimendan group and the placebo group (6.68±3.96 vs. 6.06±3.89; mean difference, 0.61; 95% confidence interval [CI], −0.07 to 1.29; P=0.053). Mortality at 28 days was 34.5% in the levosimendan group and 30.9% in the placebo group (absolute difference, 3.6 percentage points; 95% CI, −4.5 to 11.7; P=0.43). Among patients requiring ventilation at baseline, those in the levosimendan group were less likely than those in the placebo group to be successfully weaned from mechanical ventilation over the period of 28 days (hazard ratio, 0.77; 95% CI, 0.60 to 0.97; P=0.03). More patients in the levosimendan group than in the placebo group had supraventricular tachyarrhythmia (3.1% vs. 0.4%; absolute difference, 2.7 percentage points; 95% CI, 0.1 to 5.3; P=0.04). CONCLUSIONS The addition of levosimendan to standard treatment in adults with sepsis was not associated with less severe organ dysfunction or lower mortality. Levosimendan was associated with a lower likelihood of successful weaning from mechanical ventilation and a higher risk of supraventricular tachyarrhythmia. (Funded by the NIHR Efficacy and Mechanism Evaluation Programme and others; LeoPARDS Current Controlled Trials number, ISRCTN12776039.

    Crohn's disease activity index and Vienna classification - Is it worthwhile to calculate before surgery?

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    Background: Crohn's disease (CD) patients with increased disease activity may reveal an increased risk for perioperative complications. The `Crohn's disease activity index' (CDAI) and the `Vienna classification' (VC) were developed for standardized disease activity estimations. The significance of these scores to predict extent, type and early outcome of surgery in CD patients was analyzed. Methods: In 179 surgically treated CD patients, the CDAI and VC were assessed from a prospective database. Relations of the scores with CD risk factors, type, number, location and complications of surgery were analyzed. Results: VC behavior and location subtypes were associated with distinct types of surgery (i.e. `strictureplasty' in `stricturing disease', `colon surgery' in `colon involvement'), but not with surgery type and extent or outcome. Surgery extent (i.e. with 5 vs. 3 `surgical sites' 425 +/- 25 vs. 223.3 +/- 25) and complications (357.1 +/- 36.9 (with) vs. 244.4 +/- 13 (without)) were associated with elevated CDAI levels; however, nicotine abuse remained the only significant risk factor for perioperative complications after multiple logistic regression. Conclusion: The significance of VC or CDAI for predicting the extent of surgery or complications is limited. None of the tested variables except preoperative nicotine abuse influenced the likelihood for perioperative complications. Copyright (c) 2006 S. Karger AG, Base

    Estimating the cost-effectiveness of detecting cases of chronic hepatitis C infection on reception into prison

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    Background In England and Wales where less than 1% of the population are Injecting drug users (IDUs), 97% of HCV reports are attributed to injecting drug use. As over 60% of the IDU population will have been imprisoned by the age of 30 years, prison may provide a good location in which to offer HCV screening and treatment. The aim of this work is to examine the cost effectiveness of a number of alternative HCV case-finding strategies on prison reception Methods A decision analysis model embedded in a model of the flow of IDUs through prison was used to estimate the cost effectiveness of a number of alternative case-finding strategies. The model estimates the average cost of identifying a new case of HCV from the perspective of the health care provider and how these estimates may evolve over time. Results The results suggest that administering verbal screening for a past positive HCV test and for ever having engaged in illicit drug use prior to the administering of ELISA and PCR tests can have a significant impact on the cost effectiveness of HCV case-finding strategies on prison reception; the discounted cost in 2017 being £2,102 per new HCV case detected compared to £3,107 when no verbal screening is employed. Conclusion The work here demonstrates the importance of targeting those individuals that have ever engaged in illicit drug use for HCV testing in prisons, these individuals can then be targeted for future intervention measures such as treatment or monitored to prevent future transmission

    Induction immunosuppression in adults undergoing liver transplantation: a network meta-analysis

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    BACKGROUND: Liver transplantation is considered the definitive treatment for people with liver failure. As part of post-liver transplantation management, immunosuppression (suppressing the host immunity) is given to prevent graft rejections. Immunosuppressive drugs can be classified into those that are used for a short period during the beginning phase of immunosuppression (induction immunosuppression) and those that are used over the entire lifetime of the individual (maintenance immunosuppression), because it is widely believed that graft rejections are more common during the first few months after liver transplantation. Some drugs such as glucocorticosteroids may be used for both induction and maintenance immunosuppression because of their multiple modalities of action. There is considerable uncertainty as to whether induction immunosuppression is necessary and if so, the relative efficacy of different immunosuppressive agents. OBJECTIVES: To assess the comparative benefits and harms of different induction immunosuppressive regimens in adults undergoing liver transplantation through a network meta-analysis and to generate rankings of the different induction immunosuppressive regimens according to their safety and efficacy. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, Science Citation Index Expanded, World Health Organization International Clinical Trials Registry Platform, and trials registers until July 2019 to identify randomised clinical trials in adults undergoing liver transplantation. SELECTION CRITERIA: We included only randomised clinical trials (irrespective of language, blinding, or status) in adults undergoing liver transplantation. We excluded randomised clinical trials in which participants had multivisceral transplantation and those who already had graft rejections. DATA COLLECTION AND ANALYSIS: We performed a network meta-analysis with OpenBUGS using Bayesian methods and calculated the odds ratio (OR), rate ratio, and hazard ratio (HR) with 95% credible intervals (CrIs) based on an available case analysis, according to National Institute of Health and Care Excellence Decision Support Unit guidance. MAIN RESULTS: We included a total of 25 trials (3271 participants; 8 treatments) in the review. Twenty-three trials (3017 participants) were included in one or more outcomes in the review. The trials that provided the information included people undergoing primary liver transplantation for various indications and excluded those with HIV and those with renal impairment. The follow-up in the trials ranged from three to 76 months, with a median follow-up of 12 months among trials. All except one trial were at high risk of bias, and the overall certainty of evidence was very low. Overall, approximately 7.4% of people who received the standard regimen of glucocorticosteroid induction died and 12.2% developed graft failure. All-cause mortality and graft failure was lower with basiliximab compared with glucocorticosteroid induction: all-cause mortality (HR 0.53, 95% CrI 0.31 to 0.93; network estimate, based on 2 direct comparison trials (131 participants; low-certainty evidence)); and graft failure (HR 0.44, 95% CrI 0.28 to 0.70; direct estimate, based on 1 trial (47 participants; low-certainty evidence)). There was no evidence of differences in all-cause mortality and graft failure between other induction immunosuppressants and glucocorticosteroids in either the direct comparison or the network meta-analysis (very low-certainty evidence). There was also no evidence of differences in serious adverse events (proportion), serious adverse events (number), renal failure, any adverse events (proportion), any adverse events (number), liver retransplantation, graft rejections (any), or graft rejections (requiring treatment) between other induction immunosuppressants and glucocorticosteroids in either the direct comparison or the network meta-analysis (very low-certainty evidence). However, because of the wide CrIs, clinically important differences in these outcomes cannot be ruled out. None of the studies reported health-related quality of life. FUNDING: the source of funding for 14 trials was drug companies who would benefit from the results of the study; two trials were funded by neutral organisations who have no vested interests in the results of the study; and the source of funding for the remaining nine trials was unclear. AUTHORS' CONCLUSIONS: Based on low-certainty evidence, basiliximab induction may decrease mortality and graft failure compared to glucocorticosteroids induction in people undergoing liver transplantation. However, there is considerable uncertainty about this finding because this information is based on small trials at high risk of bias. The evidence is uncertain about the effects of different induction immunosuppressants on other clinical outcomes, including graft rejections. Future randomised clinical trials should be adequately powered, employ blinding, avoid post-randomisation dropouts (or perform intention-to-treat analysis), and use clinically important outcomes such as mortality, graft failure, and health-related quality of life

    Low frequency radio properties of the z>5 quasar population

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    Optically luminous quasars at z > 5 are important probes of super-massive black hole (SMBH) formation. With new and future radio facilities, the discovery of the brightest low-frequency radio sources in this epoch would be an important new probe of cosmic reionization through 21-cm absorption experiments. In this work, we systematically study the low-frequency radio properties of a sample of 115 known spectroscopically confirmed z > 5 quasars using the second data release of the Low Frequency Array (LOFAR) Two Metre Sky survey (LoTSS-DR2), reaching noise levels of ∼80 µJy beam−1 (at 144 MHz) over an area of ∼ 5720 deg2 . We find that 41 sources (36%) are detected in LoTSS-DR2 at > 2σ significance and we explore the evolution of their radio properties (power, spectral index, and radio loudness) as a function of redshift and rest-frame ultra-violet properties. We obtain a median spectral index of −0.29+0.10 −0.09 by stacking 93 quasars using LoTSS-DR2 and Faint Images of the Radio Sky at Twenty Centimetres (FIRST) data at 1.4 GHz, in line with observations of quasars at z < 3. We compare the radio loudness of the high-z quasar sample to a lower-z quasar sample at z ∼ 2 and find that the two radio loudness distributions are consistent with no evolution, although the low number of high-z quasars means that we cannot rule out weak evolution. Furthermore, we make a first order empirical estimate of the z = 6 quasar radio luminosity function, which is used to derive the expected number of high-z sources that will be detected in the completed LoTSS survey. This work highlights the fact that new deep radio observations can be a valuable tool in selecting high-z quasar candidates for follow-up spectroscopic observations by decreasing contamination of stellar dwarfs and reducing possible selection biases introduced by strict colour cuts

    Recognizing Speech in a Novel Accent: The Motor Theory of Speech Perception Reframed

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    The motor theory of speech perception holds that we perceive the speech of another in terms of a motor representation of that speech. However, when we have learned to recognize a foreign accent, it seems plausible that recognition of a word rarely involves reconstruction of the speech gestures of the speaker rather than the listener. To better assess the motor theory and this observation, we proceed in three stages. Part 1 places the motor theory of speech perception in a larger framework based on our earlier models of the adaptive formation of mirror neurons for grasping, and for viewing extensions of that mirror system as part of a larger system for neuro-linguistic processing, augmented by the present consideration of recognizing speech in a novel accent. Part 2 then offers a novel computational model of how a listener comes to understand the speech of someone speaking the listener's native language with a foreign accent. The core tenet of the model is that the listener uses hypotheses about the word the speaker is currently uttering to update probabilities linking the sound produced by the speaker to phonemes in the native language repertoire of the listener. This, on average, improves the recognition of later words. This model is neutral regarding the nature of the representations it uses (motor vs. auditory). It serve as a reference point for the discussion in Part 3, which proposes a dual-stream neuro-linguistic architecture to revisits claims for and against the motor theory of speech perception and the relevance of mirror neurons, and extracts some implications for the reframing of the motor theory

    The role of childhood social position in adult type 2 diabetes: Evidence from the English Longitudinal Study of Ageing

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    Copyright @ 2014 Pikhartova et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.This article has been made available through the Brunel Open Access Publishing Fund.Background: Socioeconomic circumstances in childhood and early adulthood may influence the later onset of chronic disease, although such research is limited for type 2 diabetes and its risk factors at the different stages of life. The main aim of the present study is to examine the role of childhood social position and later inflammatory markers and health behaviours in developing type 2 diabetes at older ages using a pathway analytic approach. Methods. Data on childhood and adult life circumstances of 2,994 men and 4,021 women from English Longitudinal Study of Ageing (ELSA) were used to evaluate their association with diabetes at age 50 years and more. The cases of diabetes were based on having increased blood levels of glycated haemoglobin and/or self-reported medication for diabetes and/or being diagnosed with type 2 diabetes. Father's job when ELSA participants were aged 14 years was used as the measure of childhood social position. Current social characteristics, health behaviours and inflammatory biomarkers were used as potential mediators in the statistical analysis to assess direct and indirect effects of childhood circumstances on diabetes in later life. Results: 12.6 per cent of participants were classified as having diabetes. A disadvantaged social position in childhood, as measured by father's manual occupation, was associated at conventional levels of statistical significance with an increased risk of type 2 diabetes in adulthood, both directly and indirectly through inflammation, adulthood social position and a risk score constructed from adult health behaviours including tobacco smoking and limited physical activity. The direct effect of childhood social position was reduced by mediation analysis (standardised coefficient decreased from 0.089 to 0.043) but remained statistically significant (p = 0.035). All three indirect pathways made a statistically significantly contribution to the overall effect of childhood social position on adulthood type 2 diabetes. Conclusions: Childhood social position influences adult diabetes directly and indirectly through inflammatory markers, adulthood social position and adult health behaviours. © 2014Pikhartova et al.; licensee BioMed Central Ltd.Economic and Social Research Council-funded International Centre for Life Course Studies in Society and Health (RES-596-28-0001)
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