2,872 research outputs found
Learning by hiring: the effects of scientists’ inbound mobility on research performance in academia
This study investigates the effects of scientists’ inbound mobility on the research performance of incumbent scientists in an academic setting. The theoretical framework integrates insights from learning theory and social comparison theory to suggest two main mechanisms behind these effects, localized learning and social comparison. The authors propose several hypotheses about the conditions that might intensify or weaken such effects. Specifically, the arrival of new scientific personnel is likely to exert stronger positive effects on the performance of incumbent scientists with shorter (cf. longer) organizational tenure; in addition, academic departments with less diversified expertise and with higher levels of internal collaborations likely reap greater benefits from learning by hiring. The empirical findings, based on a longitudinal analysis of a sample of 94 U.S. academic chemical engineering departments, provide empirical support for these contentions
Flavor violating leptonic decays of τ and μ leptons in the Standard Model with massive neutrinos
We have revisited the computations of the flavor
violating leptonic decays of the τ and μ leptons into three
lighter charged leptons in the Standard Model with massive
neutrinos. We were driven by a claimed unnaturally large
branching ratio predicted for the τ
− → μ
−
l
+
l
− (l = μ, e)
decays (Pham, Eur Phys J C 8:513 1999), which was at odds
with the corresponding predictions for the μ
− → e−e−e+
processes (Petcov, Sov J Nucl Phys 25:340 1977). In contrast
with the prediction in [17], our results are strongly suppressed
and in good agreement with the approximationmade
in Ref. [15], where masses and momenta of the external particles
were neglected in order to deal with the loop integrals.
However -as a result of keeping external momenta and
masses in the computation of the dominant penguin and box
diagrams- we even find slightly smaller branching fractions.
Therefore, we confirm that any future observation of such
processes would be an unambiguous manifestation of new
physics beyond the Standard Model.Finally, we also
acknowledge support from Conacyt through projects FOINS-296-2016
(Fronteras de la Ciencia), and 236394 and 250628 (Ciencia Básica)
Local Difference Measures between Complex Networks for Dynamical System Model Evaluation
Acknowledgments We thank Reik V. Donner for inspiring suggestions that initialized the work presented herein. Jan H. Feldhoff is credited for providing us with the STARS simulation data and for his contributions to fruitful discussions. Comments by the anonymous reviewers are gratefully acknowledged as they led to substantial improvements of the manuscript.Peer reviewedPublisher PD
Examining Alternative Measures of Social Disadvantage Among Asian Americans: The Relevance of Economic Opportunity, Subjective Social Status, and Financial Strain for Health
Socioeconomic position is often operationalized as education, occupation, and income. However, these measures may not fully capture the process of socioeconomic disadvantage that may be related to morbidity. Economic opportunity, subjective social status, and financial strain may also place individuals at risk for poor health outcomes. Data come from the Asian subsample of the 2003 National Latino and Asian American Study (n = 2095). Regression models were used to examine the associations between economic opportunity, subjective social status, and financial strain and the outcomes of self-rated health, body mass index, and smoking status. Education, occupation, and income were also investigated as correlates of these outcomes. Low correlations were observed between all measures of socioeconomic status. Economic opportunity was robustly negatively associated with poor self-rated health, higher body mass index, and smoking, followed by financial strain, then subjective social status. Findings show that markers of socioeconomic position beyond education, occupation, and income are related to morbidity among Asian Americans. This suggests that potential contributions of social disadvantage to poor health may be understated if only conventional measures are considered among immigrant and minority populations
Alcohol consumption and body composition in a population-based sample of elderly Australian men
Background: Alcohol is calorie dense, and impacts activity, appetite and lipid processing. The aim of this study was to therefore investigate the association between alcohol consumption and components of body composition including bone, fat and lean tissue.Methods: Participants were recruited from a randomly selected, population-based sample of 534 men aged 65 years and older enrolled in the Geelong Osteoporosis Study. Alcohol intake was ascertained using a food frequency questionnaire and the sample categorised as nondrinkers or alcohol users who consumed B2, 3–4 or C5 standard drinks on a usual drinking day. Bone mineral density (BMD), lean body mass and body fat mass were measured using dual energy X-ray absorptiometry; overall adiposity (%body fat), central adiposity (%truncal fat) and body mass index (BMI) were calculated. Bone quality was determined by quantitative heel ultrasound (QUS).Results: There were 90 current non-drinkers (16.9 %), 266 (49.8 %) consumed 1–2 drinks/day, 104 (19.5 %) 3–4 drinks/day and 74 (13.8 %) C5 drinks/day. Those consuming C5 drinks/day had greater BMI (?4.8 %), fat mass index (?20.1 %), waist circumference (?5.0 %), %body fat (?15.2 %) and proportion of trunk fat (?5.3 %) and lower lean mass (-5.0 %) than non-drinkers after adjustment for demographic and lifestyle factors. Furthermore, they were more likely to be obese than non-drinkers according to criteria based on BMI (OR = 2.83, 95 %CI 1.10–7.29) or waist circumference (OR = 3.36, 95 %CI 1.32–8.54). There was an inverse relationship between alcohol consumption and QUS parameters and BMD at the mid forearm site; no differences were detected for BMD at other skeletal sites.Conclusion: Higher alcohol intake was associated with greater total and central adiposity and reduced bone quality.<br /
Effects of an outpatient education program in patients with uncontrolled asthma
OBJECTIVE: To evaluate the effects of an outpatient education program in patients with uncontrolled asthma. METHODS: This was an uncontrolled study evaluating an educational intervention and involving patients with uncontrolled asthma ≥ 14 years of age. The participants completed a questionnaire designed to assess the level of asthma control, the inhalation technique, and quality of life. All of the patients underwent pulmonary function testing, after which they participated in an education program consisting of one 45-min face-to-face session, followed by phone interviews at two, four, and eight weeks. The participants were reevaluated after three months. RESULTS: Sixty-three patients completed the study. There was a significant improvement in the level of asthma control (p < 0.001). Of the 63 patients, 28 (44.4%) and 6 (9.5%) were classified as having partially controlled asthma and controlled asthma, respectively. The mean FEV1 was 63.0 ± 20.0% and 68.5 ± 21.2% of the predicted value prior to and after the educational intervention, respectively (p = 0.002), and all of the quality of life scores improved (p < 0.05 for all). The same was true for the proportion of patients prior to and after the educational intervention using the proper inhalation technique when using metered dose inhalers (15.4% vs. 46.2%; p = 0.02) and dry powder inhalers (21.3% vs. 76.6%; p < 0.001). The logistic regression analysis revealed that an incorrect inhalation technique identified during the first evaluation was independently associated with a favorable response to the educational intervention. CONCLUSIONS: This study suggests that an outpatient education program for asthma patients improves the level of asthma control, lung function parameters, and quality of life. An incorrect inhalation technique identified during the first evaluation was predictive of a favorable response to the educational intervention
Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli
Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts. Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins. Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets
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