572 research outputs found
Is famine exposure during developmental life in rural Bangladesh associated with a metabolic and epigenetic signature in young adulthood? A historical cohort study
Objectives Famine exposure in utero can ‘programme’ an individual towards type 2 diabetes and obesity in later life. We sought to identify, (1) whether Bangladeshis exposed to famine during developmental life are programmed towards diabetes and obesity, (2) whether this programming was specific to gestational or postnatal exposure windows and (3) whether epigenetic differences were associated with famine exposure.
Design A historical cohort study was performed as part of a wider cross-sectional survey. Exposure to famine was defined through birth date and historical records and participants were selected according to: (A) exposure to famine in postnatal life, (B) exposure to famine during gestation and (C) unexposed.
Setting Matlab, a rural area in the Chittagong division of Bangladesh.
Participants Young adult men and women (n=190) recruited to a historical cohort study with a randomised subsample included in an epigenetic study (n=143).
Outcome measures Primary outcome measures of weight, body mass index and oral glucose tolerance tests (0 and 120 min glucose). Secondary outcome measures included DNA methylation using genome-wide and targeted analysis of metastable epialleles sensitive to maternal nutrition.
Results More young adults exposed to famine in gestation were underweight than those postnatally exposed or unexposed. In contrast, more young adults exposed to famine postnatally were overweight compared to those gestationally exposed or unexposed. Underweight adults exposed to famine in gestation in utero were hyperglycaemic following a glucose tolerance test, and those exposed postnatally had elevated fasting glucose, compared to those unexposed. Significant differences in DNA methylation at seven metastable epialleles (VTRNA2-1, PAX8, PRDM-9, near ZFP57, near BOLA, EXD3) known to vary with gestational famine exposure were identified.
Conclusions Famine exposure in developmental life programmed Bangladeshi offspring towards diabetes and obesity in adulthood but gestational and postnatal windows of exposure had variable effects on phenotype. DNA methylation differences were replicated at previously identified metastable epialleles sensitive to periconceptual famine exposure
Provider Attitudes toward the Voluntary Medical Male Circumcision Scale-Up in Kenya, South Africa, Tanzania and Zimbabwe.
Countries participating in voluntary medical male circumcision (VMMC) scale-up have adopted most of six elements of surgical efficiency, depending on national policy. However, effective implementation of these elements largely depends on providers' attitudes and subsequent compliance. We explored the concordance between recommended practices and providers' perceptions toward the VMMC efficiency elements, in part to inform review of national policies. As part of Systematic Monitoring of the VMMC Scale-up (SYMMACS), we conducted a survey of VMMC providers in Kenya, South Africa, Tanzania, and Zimbabwe. SYMMACS assessed providers' attitudes and perceptions toward these elements in 2011 and 2012. A restricted analysis using 2012 data to calculate unadjusted odds ratios and 95% confidence intervals for the country effect on each attitudinal outcome was done using logistic regression. As only two countries allow more than one cadre to perform the surgical procedure, odds ratios looking at country effect were adjusted for cadre effect for these two countries. Qualitative data from open-ended responses were used to triangulate with quantitative analyses. This analysis showed concordance between each country's policies and provider attitudes toward the efficiency elements. One exception was task-shifting, which is not authorized in South Africa or Zimbabwe; providers across all countries approved this practice. The decision to adopt efficiency elements is often based on national policies. The concordance between the policies of each country and provider attitudes bodes well for compliance and effective implementation. However, study findings suggest that there may be need to consult providers when developing national policies.\u
Boundary work: An interpretive ethnographic perspective on negotiating and leveraging cross-cultural identity
The complexity of global organizations highlights the importance of members’ ability to span diverse boundaries that may be defined by organization structures, national borders, and/or a variety of cultures associated with organization, nation-based societal and work cultures, industries, and/or professions. Based on ethnographic research in a Japan–US binational firm, the paper describes and analyzes the boundary role performance of the firm\u27s Japanese members. It contributes toward theory on boundary spanning by introducing a “cultural identity negotiation” conceptual framework. We show boundary spanning as a process shaped through the interplay of the contextual issues that make a boundary problematic; an individual\u27s multiple repertoires of cultural knowledge; and the individual boundary spanner\u27s “negotiation”, through interaction with others, of his/her cultural identities – the sense of “who I am” as a cultural being that is fundamental to an individual\u27s self-concept. At the same time, we make transparent the epistemological and methodological foundations of an interpretive ethnographic approach, demonstrating its value for understanding complex organizational processes. Research findings have practical implications for the selection and training of an organization\u27s employees, particularly of persons who may be considered “bicultural”
Spatially distributed dendritic resonance selectively filters synaptic input
© 2014 Laudanski et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.An important task performed by a neuron is the selection of relevant inputs from among thousands of synapses impinging on the dendritic tree. Synaptic plasticity enables this by strenghtening a subset of synapses that are, presumably, functionally relevant to the neuron. A different selection mechanism exploits the resonance of the dendritic membranes to preferentially filter synaptic inputs based on their temporal rates. A widely held view is that a neuron has one resonant frequency and thus can pass through one rate. Here we demonstrate through mathematical analyses and numerical simulations that dendritic resonance is inevitably a spatially distributed property; and therefore the resonance frequency varies along the dendrites, and thus endows neurons with a powerful spatiotemporal selection mechanism that is sensitive both to the dendritic location and the temporal structure of the incoming synaptic inputs.Peer reviewe
Recommended from our members
Externalizing, internalizing and fostering commitment: the case of born-global firms in emerging economies
This paper examines the HR practices of mature born-global firms from twenty-nine emerging economies. Through an examination of large scale survey data the paper questions the extent to which firm size impacts the employment of temporary workers, the employment of skilled workers and the extent of employee training. Findings suggest that as firm size increases the use of temporary workers decreases, the number of skilled workers increases and the number of employees receiving training also increases. The paper highlights how born-global firms are able to shift away from externalized, market-based approaches towards more internalized, commitment-based approaches in order to survive, adapt and grow
QCD and strongly coupled gauge theories : challenges and perspectives
We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.Peer reviewe
NICE : A Computational solution to close the gap from colour perception to colour categorization
The segmentation of visible electromagnetic radiation into chromatic categories by the human visual system has been extensively studied from a perceptual point of view, resulting in several colour appearance models. However, there is currently a void when it comes to relate these results to the physiological mechanisms that are known to shape the pre-cortical and cortical visual pathway. This work intends to begin to fill this void by proposing a new physiologically plausible model of colour categorization based on Neural Isoresponsive Colour Ellipsoids (NICE) in the cone-contrast space defined by the main directions of the visual signals entering the visual cortex. The model was adjusted to fit psychophysical measures that concentrate on the categorical boundaries and are consistent with the ellipsoidal isoresponse surfaces of visual cortical neurons. By revealing the shape of such categorical colour regions, our measures allow for a more precise and parsimonious description, connecting well-known early visual processing mechanisms to the less understood phenomenon of colour categorization. To test the feasibility of our method we applied it to exemplary images and a popular ground-truth chart obtaining labelling results that are better than those of current state-of-the-art algorithms
An analysis of simple computational strategies to facilitate the design of functional molecular information processors
BACKGROUND: Biological macromolecules (DNA, RNA and proteins) are capable of processing physical or chemical inputs to generate outputs that parallel conventional Boolean logical operators. However, the design of functional modules that will enable these macromolecules to operate as synthetic molecular computing devices is challenging. RESULTS: Using three simple heuristics, we designed RNA sensors that can mimic the function of a seven-segment display (SSD). Ten independent and orthogonal sensors representing the numerals 0 to 9 are designed and constructed. Each sensor has its own unique oligonucleotide binding site region that is activated uniquely by a specific input. Each operator was subjected to a stringent in silico filtering. Random sensors were selected and functionally validated via ribozyme self cleavage assays that were visualized via electrophoresis. CONCLUSIONS: By utilising simple permutation and randomisation in the sequence design phase, we have developed functional RNA sensors thus demonstrating that even the simplest of computational methods can greatly aid the design phase for constructing functional molecular devices. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12859-016-1297-x) contains supplementary material, which is available to authorized users
RNAstructure: software for RNA secondary structure prediction and analysis
<p>Abstract</p> <p>Background</p> <p>To understand an RNA sequence's mechanism of action, the structure must be known. Furthermore, target RNA structure is an important consideration in the design of small interfering RNAs and antisense DNA oligonucleotides. RNA secondary structure prediction, using thermodynamics, can be used to develop hypotheses about the structure of an RNA sequence.</p> <p>Results</p> <p>RNAstructure is a software package for RNA secondary structure prediction and analysis. It uses thermodynamics and utilizes the most recent set of nearest neighbor parameters from the Turner group. It includes methods for secondary structure prediction (using several algorithms), prediction of base pair probabilities, bimolecular structure prediction, and prediction of a structure common to two sequences. This contribution describes new extensions to the package, including a library of C++ classes for incorporation into other programs, a user-friendly graphical user interface written in JAVA, and new Unix-style text interfaces. The original graphical user interface for Microsoft Windows is still maintained.</p> <p>Conclusion</p> <p>The extensions to RNAstructure serve to make RNA secondary structure prediction user-friendly. The package is available for download from the Mathews lab homepage at <url>http://rna.urmc.rochester.edu/RNAstructure.html</url>.</p
Racial/Ethnic Disparities in Exercise and Dietary Behaviors of Middle-Aged and Older Adults
BackgroundDifferences in health behaviors may be important contributors to racial/ethnic disparities in the health status of adults. Studies to date have not compared whether there are health behavior differences in exercise and dietary behaviors among middle-age and older adults in the four largest racial/ethnic categories.ObjectiveTo investigate racial/ethnic differences in exercise and dietary behaviors of middle-aged and older adults.DesignWe used data from the 2007 California Health Interview Survey. Multivariable logistic regression was used to examine interactions between age and race/ethnicity in predicting two categories of health behaviors. Analyses were conducted adjusting for sociodemographic characteristics, health insurance status, and healthcare utilization.ParticipantsA population-based sample of 33,189 California adults 45 years old and older: 26,522 non-Hispanic whites, 1,686 African American/blacks, 2,565 Asian/Pacific Islanders (1,741 English-proficient; 824 limited English-proficient), and 2,416 Latinos (1,538 English-proficient; 878 limited English-proficient).Main measuresSelf-report leisure-time physical activity (moderate and vigorous) and daily consumption of fruits and vegetables.Key resultsRacial/ethnic minorities generally engaged in less healthy exercise and dietary behaviors than whites, with differences more pronounced in middle adulthood. The disparities were the greatest among English-proficient minorities. Specifically, among middle-aged respondents, all racial/ethnic minorities engaged in less vigorous physical activity than whites (ORs range = 0.28 to 0.73; 95% CI range = 0.16-1.00). Additionally, middle-aged, English-proficient minorities engaged in less moderate physical activity compared to whites (ORs range =0.57 to 0.67; 95% CI range = 0.45-0.79). Furthermore, middle-aged, English-proficient Latinos had a poorer diet than whites (OR = 0.54; 0.39-0.75). Few significant racial/ethnic differences emerged in the exercise and dietary behaviors of older adults.ConclusionsRacial/ethnic disparities in exercise and dietary behaviors are most notable among middle-aged, acculturated minorities. Results highlight the need to promote positive exercise and dietary behaviors during critical preventive ages, when racial/ethnic disparities are large and the potential to prevent chronic disease is great
- …
