532 research outputs found

    The relative dependence of Spanish landscape pattern on environmental and geographical variables over time

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    The analysis of the dependence of landscape patterns on environment was carried out in order to investigate the landscape structure evolution of Spain. The underlying concept was that the dependence between landscape spatial structure and environmental factors could be gradually decreasing over time. Land cover data were recorded from aerial photo interpretation of 206 4 x 4 km(2) samples from three different years: 1956, 1984 and 1998. Geographical variables were taken into consideration together with the purely environmental ones. General Linear Models of repeated measures were then used to segregate environmental from geographical effects on the pattern of the land cover patches of the samples. Aridity, lithology and topography were the environmental factors used to analyse structural indices of landscape. Landscape composition has a higher dependence on environment than configuration. Environmental variables showed higher correlations with landscape composition and configuration than geographical variables. Ail-long them, overall the climatic aridity and topography significantly accounted for more variation than did lithology. There was a high degree of stability in land cover composition over time, with some significant exceptions. Nevertheless, the registered increase of fragmentation over time has demonstrated that configuration measures are needed to fully assess landscape change

    Far from random? The role of homophily in student supervision

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    The paper studies racial and gender homophily in student supervision relationships in a context of social transformations, South Africa academia. We develop a technique to separate choice homophily from that induced by the system. Comprising two permutation tests repeated at two levels of aggregation, system and departments. We find clear evidence of homophily in student supervision, along racial lines in particular. Roughly half of the observed homophily is induced by the departments composition and stays constant over time. Overall, choice homophily has similar magnitude along racial and gender dimensions. Further, we ask where choice homophily originates in the demographic groups of students and professors. We find that white (male) students have high tendency to form same-type relations, while among professors it is black (female) who display the higher frequency. Group differences show that choice homophily is likely to originate from students in the former majority

    Networking strategies in streptomyces coelicolor

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    We are interested the soil dwelling bacteria Streptomyces coelicolor because its cells grow end to end in a line. New branches have the potential to extend from any point along this line and the result is a network of branches and connections. This is a novel form of colonisation in the bacterial world and it is advantageous for spreading through an environment resourcefully. Networking protocols for communication technologies have similar pressures to be resourceful in terms of time, computing power, and energy. In this preliminary investigation we design a computer model of the biological system to understand its limitations and strategies for survival. The decentralised capacity for organisation of both the bacterial system and the model reflects well on the now-popular conventions for path finding and ad hoc network building in human technologies. The project will ultimately become a comparison of strategies between nature and the man-made

    Ph.D. research output in STEM: the role of gender and race in supervision

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    We study whether student-advisor gender and race couples matter for publication productivity of Ph.D. students in South Africa. We consider the sample of all Ph.D.s in STEM graduating between 2000 and 2014, after the recent systematic introduction of doctoral programs in this country. We investigate the joint effects of gender and race for the whole sample and looking separately at the sub-samples of (1) whitewhite; (2) black-black; and (3) black-white student-advisor couples. We find early career productivity differences: while female students publish on average 10% to 20% fewer articles than males, this is true mainly for female students working with a male advisor, not for those working with a female one. These disparities are similar, though more pronounced, when looking at the joint effects of gender and race for the white-white and black-black student-advisor pairs. We also explore whether publication productivity differences change significantly for students with a high, medium, or low “productivity-profile”, and find that they are U-shaped. Female students with a high (or low) “productivity-profile” studying with female advisors are as productive than male students with a high (or low) “productivity-profile” studying with male advisor

    Orthorexia nervosa: A cross-sectional study among athletes competing in endurance sports in Northern Italy

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    Orthorexia Nervosa (ON) is an eating disorder marked by an excessive control over the quality of the food eaten. Some groups present a higher prevalence of ON and people practicing sports seems to be a population at risk. The aim of this study is to assess the prevalence of ON in endurance athletes and to compare their prevalence with the ones recorded in the sedentary population and in athletes playing other sports. A cross-sectional survey was carried in Piedmont and Valle d'Aosta, among 549 participants in local sports events aged between 18 and 40 years old. The questionnaire assessed socio-demographic characteristics, physical activity, nutrition and diet, the ORTO-15 questionnaire and Eating Habits Questionnaire (EHQ). The sample was stratified according to the minutes of sport practiced in a week and the type of sport played. Crosstab chi-square analyses to determine group differences on categorical variables (e.g. gender), and ANOVAs or t tests to determine group differences on continuous variables were performed. When required, post hoc analyses were performed. Linear and logistic regressions were performed in order to investigate potential predictors of orthorexia. The EHQ mean scores ware significantly higher in people who practice sports >150 minutes/week. EHQ score resulted to be positively correlated with endurance sport practice >150 minutes/week, with a coefficient of 2.407 (I.C.95% [0.27;4.54], p = 0.027). Analyses carried out suggested a correlation between endurance sport practice and ON. Further studies should be performed to identify diagnostic criteria and to compare different questionnaire used to assess them

    Distinct ecotypes within a natural haloarchaeal population enable adaptation to changing environmental conditions without causing population sweeps

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    Microbial communities thriving in hypersaline brines of solar salterns are highly resistant and resilient to environmental changes, and salinity is a major factor that deterministically influences community structure. Here, we demonstrate that this resilience occurs even after rapid osmotic shocks caused by a threefold change in salinity (a reduction from 34 to 12% salts) leading to massive amounts of archaeal cell lysis. Specifically, our temporal metagenomic datasets identified two co-occurring ecotypes within the most dominant archaeal population of the brines Haloquadratum walsbyi that exhibited different salt concentration preferences. The dominant ecotype was generally more abundant and occurred in high-salt conditions (34%); the low abundance ecotype always co-occurred but was enriched at salinities around 20% or lower and carried unique gene content related to solute transport and gene regulation. Despite their apparent distinct ecological preferences, the ecotypes did not outcompete each other presumably due to weak functional differentiation between them. Further, the osmotic shock selected for a temporal increase in taxonomic and functional diversity at both the Hqr. walsbyi population and whole-community levels supporting the specialization-disturbance hypothesis, that is, the expectation that disturbance favors generalists. Altogether, our results provide new insights into how intraspecies diversity is maintained in light of substantial gene-content differences and major environmental perturbations

    Interprofessional Communication Team for Caregivers of Patients Hospitalized in the COVID-19 Wards: Results From an Italian Experience

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    Background: During the COVID-19 pandemic, emergency restrictions did not allow clinician family meetings and relatives' visits. In Molinette Hospital, a new communication model between healthcare providers and families of COVID-19 affected patients was developed by a team of physicians and psychologists. The study's aims were to investigate caregivers' distress and to analyse their satisfaction with the communications provided. Methods: A cross-sectional study was conducted among caregivers of patients of Molinette Hospital COVID wards. Between April and June 2020, all caregivers were contacted 2 weeks after the patient's discharge/death to assess their satisfaction with the communications received through an online survey. Results: A total of 155 caregivers completed the survey. Caregivers' distress level was found to be higher in women than men (p = 0.048) and in caregivers whose relative died compared to the caregivers whose relative was discharged (p < 0.001). More than 85% of caregivers defined communication “excellent”/“very good”; being male was associated with higher satisfaction levels than women (β = −0.165, p = 0.046). Besides daily communication, 63 caregivers (40.6%) received additional support from a psychologist of the team. Conclusions: To our knowledge, this is the first study presenting, in an emergency, a new model of communication provided by a team of physicians and psychologists, and analyzing satisfaction with it. This model was highly appreciated by caregivers and it limited the discomfort caused by the restrictions on relatives' visits. It would be interesting to further evaluate the possibility of extending a communication model that includes doctors and psychologists in routine clinical practice
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