Resolution requirements for numerical simulations of transition

The resolution requirements for direct numerical simulations of transition to turbulence are investigated. A reliable resolution criterion is determined from the results of several detailed simulations of channel and boundary-layer transition

Nesiritide: Harmful or Harmless?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90328/1/phco.26.10.1465.pd

Primary skin fibroblasts as a model of Parkinson's disease

Parkinson's disease is the second most frequent neurodegenerative disorder. While most cases occur sporadic mutations in a growing number of genes including Parkin (PARK2) and PINK1 (PARK6) have been associated with the disease. Different animal models and cell models like patient skin fibroblasts and recombinant cell lines can be used as model systems for Parkinson's disease. Skin fibroblasts present a system with defined mutations and the cumulative cellular damage of the patients. PINK1 and Parkin genes show relevant expression levels in human fibroblasts and since both genes participate in stress response pathways, we believe fibroblasts advantageous in order to assess, e.g. the effect of stressors. Furthermore, since a bioenergetic deficit underlies early stage Parkinson's disease, while atrophy underlies later stages, the use of primary cells seems preferable over the use of tumor cell lines. The new option to use fibroblast-derived induced pluripotent stem cells redifferentiated into dopaminergic neurons is an additional benefit. However, the use of fibroblast has also some drawbacks. We have investigated PARK6 fibroblasts and they mirror closely the respiratory alterations, the expression profiles, the mitochondrial dynamics pathology and the vulnerability to proteasomal stress that has been documented in other model systems. Fibroblasts from patients with PARK2, PARK6, idiopathic Parkinson's disease, Alzheimer's disease, and spinocerebellar ataxia type 2 demonstrated a distinct and unique mRNA expression pattern of key genes in neurodegeneration. Thus, primary skin fibroblasts are a useful Parkinson's disease model, able to serve as a complement to animal mutants, transformed cell lines and patient tissues

Partial Volume Correction in Quantitative Amyloid Imaging.

Amyloid imaging is a valuable tool for research and diagnosis in dementing disorders. As positron emission tomography (PET) scanners have limited spatial resolution, measured signals are distorted by partial volume effects. Various techniques have been proposed for correcting partial volume effects, but there is no consensus as to whether these techniques are necessary in amyloid imaging, and, if so, how they should be implemented. We evaluated a two-component partial volume correction technique and a regional spread function technique using both simulated and human Pittsburgh compound B (PiB) PET imaging data. Both correction techniques compensated for partial volume effects and yielded improved detection of subtle changes in PiB retention. However, the regional spread function technique was more accurate in application to simulated data. Because PiB retention estimates depend on the correction technique, standardization is necessary to compare results across groups. Partial volume correction has sometimes been avoided because it increases the sensitivity to inaccuracy in image registration and segmentation. However, our results indicate that appropriate PVC may enhance our ability to detect changes in amyloid deposition

Bottom-up Infrastructures: Aligning Politics and Technology in building a Wireless Community Network

Contemporary innovation in infrastructures is increasingly characterized by a close relationship between experts and lay people. This phenomenon has attracted the attention from a wide range of disciplines, including computer-supported cooperative work (CSCW), science and technology studies (S&TS), organization studies and participatory design (PD). Connecting to this broad area of research, the article presents a qualitative case study concerning the building and maintenance of a grassroots, bottom-up information infrastructure in Italy, defined as wireless community network (WCN). Methodologically, the research is based on qualitative interviews with participants to the WCN, ethnographic observations and document analysis. The aim of the article is to understand the alignment between the technical work implied in building this bottom-up infrastructure and the political and cultural frameworks that move people to participate to this project. Relying on the field of science & technology studies, and in particular on the notions of ‘inverse infrastructure’ and ‘research in the wild’, we disclose the WCN’s peculiar innovation trajectory, localized outside conventional spaces of research and development. Overall, the presentation of the qualitative and ethnographic data allows to point out a more general reflection on bottom-up infrastructures and to enrich the academic debate concerning bottom-up infrastructuring work and other similar typologies of collaborative design projects in the domain of infrastructures

Resilience to obesity among socioeconomically disadvantaged women : the READI study

Objective: This cross-sectional study aimed to identify sociodemographic and behavioural characteristics of ‘overweight-resilient’ women, that is, women who were in a healthy body weight range, despite living in socioeconomically disadvantaged neighbourhoods that place them at increased risk of obesity. The study also aimed to test a comprehensive theoretically derived model of the associations between intrapersonal, social and environmental factors and obesity among this target group.Participants: A total of 3235 women aged 18–45 years from 80 urban and rural neighbourhoods throughout Victoria, Australia, participated in the Resilience for Eating and Activity Despite Inequality study.Measurements: Women reported height, weight, sociodemographic characteristics, leisure-time physical activity, dietary behaviours and a range of theoretically derived cognitive, social and neighbourhood environmental characteristics hypothesized to influence obesity risk. A theoretical model predicting body mass index (BMI) was tested using structural equation models.Results: Women classified as ‘resilient’ to obesity tended to be younger, born overseas, more highly educated, unmarried and to have higher or undisclosed household incomes. They engaged in more leisure-time physical activity and consumed less fast foods and soft drinks than overweight/obese women. Neighbourhood characteristics, social characteristics and cognitive characteristics all contributed to explaining variation in BMI in the hypothesized directions.Conclusions: These results demonstrate several characteristics of women appearing ‘resilient’ to obesity, despite their increased risk conferred by residing in socioeconomically disadvantaged neighbourhoods. Acknowledging the cross-sectional study design, the results advance theoretical frameworks aimed at investigating obesity risk by providing evidence in support of a comprehensive model of direct and indirect effects on obesity of neighbourhood, as well as social, cognitive and behavioural characteristics

A systematic review of intervention effects on potential mediators of children\u27s physical activity

Background : Many interventions aiming to increase children’s physical activity have been developed and implemented in a variety of settings, and these interventions have previously been reviewed; however the focus of these reviews tends to be on the intervention effects on physical activity outcomes without consideration of the reasons and pathways leading to intervention success or otherwise. To systematically review the efficacy of physical activity interventions targeting 5-12 year old children on potential mediators and, where possible, to calculate the size of the intervention effect on the potential mediator. Methods : A systematic search identified intervention studies that reported outcomes on potential mediators of physical activity among 5-12 year old children. Original research articles published between 1985 and April 2012 were reviewed. Results : Eighteen potential mediators were identified from 31 studies. Positive effects on cognitive/psychological potential mediators were reported in 15 out of 31 studies. Positive effects on social environmental potential mediators were reported in three out of seven studies, and no effects on the physical environment were reported. Although no studies were identified that performed a mediating analysis, 33 positive intervention effects were found on targeted potential mediators (with effect sizes ranging from small to large) and 73% of the time a positive effect on the physical activity outcome was reported. Conclusions : Many studies have reported null intervention effects on potential mediators of children’s physical activity; however, it is important that intervention studies statistically examine the mediating effects of interventions so the most effective strategies can be implemented in future programs

Depressive Symptoms among Pregnant Women Screened in Obstetrics Settings

Objectives: This study aimed to describe the prevalence of depressive symptomatology during pregnancy when seen in obstetric settings, the extent of treatment in this population, and specific risk factors associated with mood symptoms in pregnancy. Methods: A total of 3472 pregnant women age 18 and older were screened while waiting for their prenatal care visits in 10 obstetrics clinics using a brief (10 minute) screening questionnaire. This screen measured demographics, tobacco and alcohol (TWEAK problem alcohol use screening measure), and depression measures, including the Center for Epidemiological Studies-Depression scale (CES-D), use of antidepressant medications, past history of depression, and current treatment (i.e., medications, psychotherapy, or counseling) for depression. Results: Of women screened, 20% (n = 689) scored above the cutoff score on the CES-D, and only 13.8% of those women reported receiving any formal treatment for depression. Past history of depression, poorer overall health, greater alcohol use consequences, smoking, being unmarried, unemployment, and lower educational attainment were significantly associated with symptoms of depression during pregnancy. Conclusions: These data show that a substantial number of pregnant women screened in obstetrics settings have significant symptoms of depression, and most of them are not being monitored in treatment during this vulnerable time. This information may be used to justify and streamline systematic screening for depression in clinical encounters with pregnant women as a first step in determining which women may require further treatment for their mood symptoms. As elevations in depressive symptomatology have been associated with adverse maternal and infant outcomes, further study of the impact of psychiatric treatment in gravid women is essential.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63218/1/154099903765448880.pd

Depression in older adults: prevalence and risk factors in a primary health care sample

BACKGROUND: Depression in the geriatric population has been identified as a significant problem in view of the associated negative outcomes regarding poor functioning, increased perception of poor health and increased utilisation of medical services. Significantly associated with increased morbidity and mortality, depression has been found to be an independent cause of disability as well as adding to disability due to primary physical illnesses. Early identification and treatment of depression reduces medical costs and lessens caregiver burden. Epidemiological data and prevalence rates of geriatric depression in Africa are limited, although such data are vital to mobilise and plan government mental health initiatives aimed at screening and early intervention. OBJECTIVE: To determine the prevalence of depression and associated clinical and socio-demographic factors amongst older adult patients attending a primary health care clinic in the Ethekwini District in Kwa-Zulu Natal, South Africa. METHODS: The 15-item Geriatric Depression Scale and a socio-demographic questionnaire were administered in English to 255 geriatric outpatients, randomly selected, at a local community clinic in Durban. DATA ANALYSIS: Data were analysed using SPSS version 23®. Descriptive statistics were used to summarise the sample demographics and response rate and non-parametric statistics were used to test for associations and differences. RESULTS: A Cronbach’s alpha for the GDS was calculated (p = 0.793). Some 40% of participants screened positive for depression. Female gender, widowhood and a negative subjective health status rating were significantly associated with depression and marriage appeared to be protective (p < 0.001). Participants with a poor subjective health rating were 21 times more likely to be depressed and widowhood conferred an almost fourfold increased risk of being depressed, with widows at greater risk than widowers. No association between depression and specific medical conditions was identified. CONCLUSION: There is a high rate of undetected depression among the elderly attending a local primary health care clinic with widowhood and poor subjective health being strong predictors of mood disorders. The findings warrant replication in bigger samples.DHE

Detecting the influence of initial pioneers on succession at deep-sea vents

© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS One 7 (2012): e50015, doi:10.1371/journal.pone.0050015.Deep-sea hydrothermal vents are subject to major disturbances that alter the physical and chemical environment and eradicate the resident faunal communities. Vent fields are isolated by uninhabitable deep seafloor, so recolonization via dispersal of planktonic larvae is critical for persistence of populations. We monitored colonization near 9°50′N on the East Pacific Rise following a catastrophic eruption in order to address questions of the relative contributions of pioneer colonists and environmental change to variation in species composition, and the role of pioneers at the disturbed site in altering community structure elsewhere in the region. Pioneer colonists included two gastropod species: Ctenopelta porifera, which was new to the vent field, and Lepetodrilus tevnianus, which had been rare before the eruption but persisted in high abundance afterward, delaying and possibly out-competing the ubiquitous pre-eruption congener L. elevatus. A decrease in abundance of C. porifera over time, and the arrival of later species, corresponded to a decrease in vent fluid flow and in the sulfide to temperature ratio. For some species these successional changes were likely due to habitat requirements, but other species persisted (L. tevnianus) or arrived (L. elevatus) in patterns unrelated to their habitat preferences. After two years, disturbed communities had started to resemble pre-eruption ones, but were lower in diversity. When compared to a prior (1991) eruption, the succession of foundation species (tubeworms and mussels) appeared to be delayed, even though habitat chemistry became similar to the pre-eruption state more quickly. Surprisingly, a nearby community that had not been disturbed by the eruption was invaded by the pioneers, possibly after they became established in the disturbed vents. These results indicate that the post-eruption arrival of species from remote locales had a strong and persistent effect on communities at both disturbed and undisturbed vents.The authors received funding from National Science Foundation grant OCE-0424953, WHOI Deep Ocean Exploration Institute, WHOI Summer Student Fellow program, Woods Hole Partnership in Education Program, IFREMER and CNRS, Fondation TOTAL Chair Extreme Marine Environment, Biodiversity and Global change