451 research outputs found
Testing for Network and Spatial Autocorrelation
Testing for dependence has been a well-established component of spatial
statistical analyses for decades. In particular, several popular test
statistics have desirable properties for testing for the presence of spatial
autocorrelation in continuous variables. In this paper we propose two
contributions to the literature on tests for autocorrelation. First, we propose
a new test for autocorrelation in categorical variables. While some methods
currently exist for assessing spatial autocorrelation in categorical variables,
the most popular method is unwieldy, somewhat ad hoc, and fails to provide
grounds for a single omnibus test. Second, we discuss the importance of testing
for autocorrelation in data sampled from the nodes of a network, motivated by
social network applications. We demonstrate that our proposed statistic for
categorical variables can both be used in the spatial and network setting
Developing self-regulation for dietary temptations: intervention effects on physical, self-regulatory and psychological outcomes
We aimed to investigate whether a self-regulatory skills intervention can improve weight loss-related outcomes. Fifty-five participants (M BMI = 32.60 ± 4.86) were randomized into self-regulation training and advice groups and received two training workshops and weekly practice tasks. The self-regulation training group was trained to use six self-regulatory skills: Delayed gratification, thought control, goal setting, self-monitoring, mindfulness, and coping. The advice group received dietary and physical activity advice for weight loss. Physical, self-regulatory, and psychological measures were taken at baseline, end of intervention (week 8) and at follow-up (week 12). Using intention-to-treat analysis, weight, waist circumference, body fat and body mass index (BMI) were significantly reduced at follow-up for both groups. There were significant increases in all six self-regulatory skills and the psychological measures of self-efficacy, self-regulatory success, and physical self-worth for both groups. Results indicate that self-regulatory skills training might be as effective as dietary and physical activity advice in terms of weight loss and related outcomes
Degradation of metalaxyl and folpet by filamentous fungi isolated from Portuguese (Alentejo) vineyard soils
Degradation of xenobiotics by microbial populations is a potential method to enhance the effectiveness of ex situ or in situ bioremediation. The purpose of this study was to evaluate the impact of repeated metalaxyl and folpet treatments on soil microbial communities and to select soil fungal strains able to degrade these fungicides. Results showed enhanced degradation of metalaxyl and folpet in vineyards soils submitted to repeated treatments with these fungicides. Indeed, the greatest degradation ability was observed in vineyard soil samples submitted to greater numbers of treatments. Respiration activities, as determined in the presence of selective antibiotics in soil suspensions amended with metalaxyl and folpet, showed that the fungal population was the microbiota community most active in the degradation process. Batch cultures performed with a progressive increase of fungicide concentrations allowed the selection of five tolerant fungal strains: Penicillium sp. 1 and Penicillium sp. 2, mycelia sterila 1 and 3, and Rhizopus stolonifer. Among these strains, mycelium sterila 3 and R. stolonifer presented only in vineyard soils treated with repeated application of these fungicides and showed tolerance >1,000 mg l−1 against commercial formulations of metalaxyl (10 %) plus folpet (40 %). Using specific methods for inducing sporulation, mycelium sterila 3 was identified as Gongronella sp. Because this fungus is rare, it was compared using csM13-polymerase chain reaction (PCR) with the two known species, Gongronella butleri and G. lacrispora. The high tolerance to metalaxyl and folpet shown by Gongronella sp. and R. stolonifer might be correlated with their degradation ability. Our results point out that selected strains have potential for the bioremediation of metalaxyl and folpet in polluted soil sites
Different healthy habits between northern and southern Spanish school children
Aim: Healthy habits are influenced by several factors such as, geographical location. The aims of this study were to describe and compare healthy habits within two populations of sixth-grade primary school children (aged 11-12 years) from Northern and Southern Spain.
Subject and Methods: A cross-sectional study using two representative samples of school children was conducted. Participants came from Logroño (n=329), in the North and Granada (n=284), in the South of Spain. Socio-demographic and anthropometric variables, adherence to the Mediterranean diet, aerobic fitness, and healthy lifestyles were recorded.
Results: Boys reported higher level of physical activity and aerobic fitness than girls (p=0.000). Southern school children reported significantly higher adherence to the Mediterranean diet (♀: p=0.041; ♂: p=0.008), and lower aerobic fitness (♀: p=0.000; ♂: p=0.042) and hours of nightly sleep (♀: p=0.008, ♂: p=0.007) than Northern school children. Southern boys also reported lower levels of physical activity (p=0.013). There were slight or moderate correlations among all habits measured (physical activity, diet, screen and sleep time). Additionally, physical activity level was inversely related to body mass index in Northern boys (p=0.020) and Southern girls (p=0.024).
Conclusions: Results showed differences in physical activity, eating and sleep habits, and aerobic fitness, according to geographical location. The relationships found among lifestyle habits indicate the need of health promotion interventions nationally and considering the differences discussed here
Inferring viral quasispecies spectra from 454 pyrosequencing reads
<p>Abstract</p> <p>Background</p> <p>RNA viruses infecting a host usually exist as a set of closely related sequences, referred to as quasispecies. The genomic diversity of viral quasispecies is a subject of great interest, particularly for chronic infections, since it can lead to resistance to existing therapies. High-throughput sequencing is a promising approach to characterizing viral diversity, but unfortunately standard assembly software was originally designed for single genome assembly and cannot be used to simultaneously assemble and estimate the abundance of multiple closely related quasispecies sequences.</p> <p>Results</p> <p>In this paper, we introduce a new <b>Vi</b>ral <b>Sp</b>ectrum <b>A</b>ssembler (ViSpA) method for quasispecies spectrum reconstruction and compare it with the state-of-the-art ShoRAH tool on both simulated and real 454 pyrosequencing shotgun reads from HCV and HIV quasispecies. Experimental results show that ViSpA outperforms ShoRAH on simulated error-free reads, correctly assembling 10 out of 10 quasispecies and 29 sequences out of 40 quasispecies. While ShoRAH has a significant advantage over ViSpA on reads simulated with sequencing errors due to its advanced error correction algorithm, ViSpA is better at assembling the simulated reads after they have been corrected by ShoRAH. ViSpA also outperforms ShoRAH on real 454 reads. Indeed, 7 most frequent sequences reconstructed by ViSpA from a real HCV dataset are viable (do not contain internal stop codons), and the most frequent sequence was within 1% of the actual open reading frame obtained by cloning and Sanger sequencing. In contrast, only one of the sequences reconstructed by ShoRAH is viable. On a real HIV dataset, ShoRAH correctly inferred only 2 quasispecies sequences with at most 4 mismatches whereas ViSpA correctly reconstructed 5 quasispecies with at most 2 mismatches, and 2 out of 5 sequences were inferred without any mismatches. ViSpA source code is available at <url>http://alla.cs.gsu.edu/~software/VISPA/vispa.html</url>.</p> <p>Conclusions</p> <p>ViSpA enables accurate viral quasispecies spectrum reconstruction from 454 pyrosequencing reads. We are currently exploring extensions applicable to the analysis of high-throughput sequencing data from bacterial metagenomic samples and ecological samples of eukaryote populations.</p
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Too few staff, too many patients: A qualitative study of the impact on obstetric care providers and on quality of care in Malawi
Background: Shortages of staff have a significant and negative impact on maternal outcomes in low-income countries, but the impact on obstetric care providers in these contexts is less well documented. Despite the government of Malawi's efforts to increase the number of human resources for health, maternal mortality rates remain persistently high. Health workers' perceptions of insufficient staff or time to carry out their work can predict key variables concerning motivation and attrition, while the resulting sub-standard care and poor attitudes towards women dissuade women from facility-based delivery. Understanding the situation from the health worker perspective can inform policy options that may contribute to a better working environment for staff and improved quality of care for Malawi's women. Methods: A qualitative research design, using critical incident interviews, was used to generate a deep and textured understanding of participants' experiences. Eligible participants had performed at least one of the emergency obstetric care signal functions a in the previous three months and had experienced a demotivating critical incident within the same timeframe. Data were analysed using NVivo software. Results: Eighty-four interviews were conducted. Concerns about staff shortages and workload were key factors for over 40% of staff who stated their intention to leave their current post and for nearly two-thirds of the remaining health workers who were interviewed. The main themes emerging were: too few staff, too many patients; lack of clinical officers/doctors; inadequate obstetric skills; undermining performance and professionalism; and physical and psychological consequences for staff. Underlying factors were inflexible scheduling and staff allocations that made it impossible to deliver quality care. Conclusion: This study revealed the difficult circumstances under which maternity staff are operating and the professional and emotional toll this exacts. Systems failures and inadequate human resource management are key contributors to the gaps in provision of obstetric care and need to be addressed. Thoughtful strategies that match supply to demand, coupled with targeted efforts to support health workers, are necessary to mitigate the effects of working in this context and to improve the quality of obstetric care for women in Malawi
Postdigital Dialogue
This article is a multi-authored experimental postdigital dialogue about postdigital dialogue. Fourteen authors were invited to produce their sections, followed by two author-reviewers who examined the article as a whole. Authors were invited to reflect on Petar Jandric’s book Learning in the age of digital reason (2017) or to produce completely new insights. The article also contains a summary of book symposium on Learning in the age of digital reason held at the 2017 American Educational Research Conference (AERA). The authors are tentatively confident that this article produces more knowledge than the arithmetic sum of its constituent parts. However, they are also very aware of its limits and insist that their conclusions are not consensual or homogenous. As traditional forms of research increasingly fail to describe our current reality, they present this article as an experiment and a possible starting point for developing new dialogical research approaches fit for our postdigital reality
Measurement of the t¯tZ and t¯tW cross sections in proton-proton collisions at √s=13 TeV with the ATLAS detector
A measurement of the associated production of a top-quark pair (t¯t) with a vector boson (W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV is presented, using 36.1 fb−1 of integrated luminosity collected by the ATLAS detector at the Large Hadron Collider. Events are selected in channels with two same- or opposite-sign leptons (electrons or muons), three leptons or four leptons, and each channel is further divided into multiple regions to maximize the sensitivity of the measurement. The t¯tZ and t¯tW production cross sections are simultaneously measured using a combined fit to all regions. The best-fit values of the production cross sections are σt¯tZ=0.95±0.08stat±0.10syst pb and σt¯tW=0.87±0.13stat±0.14syst pb in agreement with the Standard Model predictions. The measurement of the t¯tZ cross section is used to set constraints on effective field theory operators which modify the t¯tZ vertex
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