4,273 research outputs found
Allergies and major depression: a longitudinal community study
© 2009 Patten et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
Deciphering the metabolic response of Mycobacterium tuberculosis to nitrogen stress.
© 2015 John Wiley & Sons Ltd.A key component to the success of Mycobacterium tuberculosis as a pathogen is the ability to sense and adapt metabolically to the diverse range of conditions encountered in vivo, such as oxygen tension, environmental pH and nutrient availability. Although nitrogen is an essential nutrient for every organism, little is known about the genes and pathways responsible for nitrogen assimilation in M. tuberculosis. In this study we have used transcriptomics and chromatin immunoprecipitation and high-throughput sequencing to address this. In response to nitrogen starvation, a total of 185 genes were significantly differentially expressed (96 up-regulated and 89 down regulated; 5% genome) highlighting several significant areas of metabolic change during nitrogen limitation such as nitrate/nitrite metabolism, aspartate metabolism and changes in cell wall biosynthesis. We identify GlnR as a regulator involved in the nitrogen response, controlling the expression of at least 33 genes in response to nitrogen limitation. We identify a consensus GlnR binding site and relate its location to known transcriptional start sites. We also show that the GlnR response regulator plays a very different role in M. tuberculosis to that in non-pathogenic mycobacteria, controlling genes involved in nitric oxide detoxification and intracellular survival instead of genes involved in nitrogen scavenging
Physical activity surveillance across the life-course: from data to policy
As a major risk factor for non-communicable diseases (NCDs), physical inactivity is a prominent challenge for public health. The purpose of this symposium is to present an overview of physical inactivity prevalence in Europe using data collected through international surveillance initiatives, while highlighting successes and discussing future challenges for utilising data to promote physical activity across the life course.
The World Health Organization (WHO) is involved in several physical activity surveillance systems on which discussions during this symposium will be based:
1. The WHO European Childhood Obesity Surveillance Initiative (COSI) is the largest survey of its kind in the world. An overview of results from the most recent round of COSI will be presented focusing on prevalence estimates for physical activity, screen time and sleep. Variations between countries of the socioeconomic determinants of physical inactivity, as well as the impact of the COVID-19 pandemic, will demonstrate the ongoing need for quality data to guide targeted policy actions in support of vulnerable groups throughout the life course.
2. The WHO’s STEPwise approach to surveillance (STEPS) survey provides important national level prevalence data on the behavioural and metabolic risk factors for NCDs. For many countries, the STEPS survey has provided the first estimates of physical inactivity and sedentary behaviour in the population and has been essential in raising awareness of the need for national policy actions to increase population levels of physical activity.
3. The European Commission, with the support of the WHO Regional Office for Europe, has established the European Union Physical Activity Focal Points Network to monitor implementation of the 23 indicators of the Health-Enhancing Physical Activity (HEPA) monitoring framework on physical activity policy development and implementation.
4. Within the European Union Physical Activity Focal Points Network, and during the COVID-19 pandemic, some countries established a survey on physical activity and screen time in children and adolescents
Experimental Tests of General Relativity
Einstein's general theory of relativity is the standard theory of gravity,
especially where the needs of astronomy, astrophysics, cosmology and
fundamental physics are concerned. As such, this theory is used for many
practical purposes involving spacecraft navigation, geodesy, and time transfer.
Here I review the foundations of general relativity, discuss recent progress in
the tests of relativistic gravity in the solar system, and present motivations
for the new generation of high-accuracy gravitational experiments. I discuss
the advances in our understanding of fundamental physics that are anticipated
in the near future and evaluate the discovery potential of the recently
proposed gravitational experiments.Comment: revtex4, 30 pages, 10 figure
Deciphering the response of Mycobacterium smegmatis to nitrogen stress using bipartite active modules.
Background
The ability to adapt to environments with fluctuating nutrient availability is vital for bacterial survival. Although essential for growth, few nitrogen metabolism genes have been identified or fully characterised in mycobacteria and nitrogen stress survival mechanisms are unknown.
Results
A global transcriptional analysis of the mycobacterial response to nitrogen stress, showed a significant change in the differential expression of 16% of the Mycobacterium smegmatis genome. Gene expression changes were mapped onto the metabolic network using Active Modules for Bipartite Networks (AMBIENT) to identify metabolic pathways showing coordinated transcriptional responses to the stress. AMBIENT revealed several key features of the metabolic response not identified by KEGG enrichment alone. Down regulated reactions were associated with the general reduction in cellular metabolism as a consequence of reduced growth rate. Up-regulated modules highlighted metabolic changes in nitrogen assimilation and scavenging, as well as reactions involved in hydrogen peroxide metabolism, carbon scavenging and energy generation.
Conclusions
Application of an Active Modules algorithm to transcriptomic data identified key metabolic reactions and pathways altered in response to nitrogen stress, which are central to survival under nitrogen limiting environments
Long-Term Medical Conditions and Major Depression: Strength of Association for Specific Conditions in the General Population
Background: The prevalence of major depression (MD) in persons with nonpsychiatric medical conditions is an indicator of clinical need in those groups, an indicator of the feasibility of screening and case-finding efforts, and a source of etiologic hypotheses. This analysis explores the prevalence of MD in the general population in relation to various long-term medical conditions. Methods: We used a dataset from a large-scale Canadian national health survey, the Canadian Community Health Survey (CCHS). The sample consisted of 115 071 subjects aged 18 years and over, randomly sampled from the Canadian population. The survey interview recorded self-reported diagnoses of various long-term medical conditions and employed a brief predictive interview for MD, the Composite International Diagnostic Interview Short Form for Major Depression. Logistic regression was used to adjust estimates of association for age and sex. Results: The conditions most strongly associated with MD were chronic fatigue syndrome (adjusted odds ratio [AOR] 7.2) and fibromyalgia (AOR 3.4). The conditions least strongly associated were hypertension (AOR 1.2), diabetes, heart disease, and thyroid disease (AOR 1.4 in each case). We found associations with various gastrointestinal, neurologic, and respiratory conditions. Conclusions: A diverse set of long-term medical conditions are associated with MD, although previous studies might have lacked power to detect some of these associations. The strength of association in prevalence data, however, varies across specific conditions
MOSFiT: Modular open source fitter for transients
Much of the progress made in time-domain astronomy is accomplished by
relating observational multi-wavelength time series data to models derived from
our understanding of physical laws. This goal is typically accomplished by
dividing the task in two: collecting data (observing), and constructing models
to represent that data (theorizing). Owing to the natural tendency for
specialization, a disconnect can develop between the best available theories
and the best available data, potentially delaying advances in our understanding
new classes of transients. We introduce MOSFiT: the Modular Open-Source Fitter
for Transients, a Python-based package that downloads transient datasets from
open online catalogs (e.g., the Open Supernova Catalog), generates Monte Carlo
ensembles of semi-analytical light curve fits to those datasets and their
associated Bayesian parameter posteriors, and optionally delivers the fitting
results back to those same catalogs to make them available to the rest of the
community. MOSFiT is designed to help bridge the gap between observations and
theory in time-domain astronomy; in addition to making the application of
existing models and creation of new models as simple as possible, MOSFiT yields
statistically robust predictions for transient characteristics, with a standard
output format that includes all the setup information necessary to reproduce a
given result. As large-scale surveys such as LSST discover entirely new classes
of transients, tools such as MOSFiT will be critical for enabling rapid
comparison of models against data in statistically consistent, reproducible,
and scientifically beneficial ways
Mathematically gifted and talented learners: Theory and practice
This is an Author's Accepted Manuscript of an article published in International Journal of Mathematical Education in Science and Technology, 40(2), 213-228, 2009, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/00207390802566907.There is growing recognition of the special needs of mathematically gifted learners. This article reviews policy developments and current research and theory on giftedness in mathematics. It includes a discussion of the nature of mathematical ability as well as the factors that make up giftedness in mathematics. The article is set in the context of current developments in Mathematics Education and Gifted Education in the UK and their implications for Science and Technology. It argues that early identification and appropriate provision for younger mathematically promising pupils capitalizes on an intellectual resource which could provide future mathematicans as well as specialists in Science or Technology. Drawing on a Vygotskian framework, it is suggested that the mathematically gifted require appropriate cognitive challenges as well as attitudinally and motivationally enhancing experiences. In the second half of this article we report on an initiative in which we worked with teachers to identify mathematically gifted pupils and to provide effective enrichment support for them, in a number of London Local Authorities. A number of significant issues are raised relating to the identification of mathematical talent, enrichment provision for students and teachers’ professional development
A disk of dust and molecular gas around a high-mass protostar
The processes leading to the birth of low-mass stars such as our Sun have
been well studied, but the formation of high-mass (> 8 x Sun's mass) stars has
heretofore remained poorly understood. Recent observational studies suggest
that high-mass stars may form in essentially the same way as low-mass stars,
namely via an accretion process, instead of via merging of several low-mass (<
8 Msun) stars. However, there is as yet no conclusive evidence. Here, we report
the discovery of a flattened disk-like structure observed at submillimeter
wavelengths, centered on a massive 15 Msun protostar in the Cepheus-A region.
The disk, with a radius of about 330 astronomical units (AU) and a mass of 1 to
8 Msun, is detected in dust continuum as well as in molecular line emission.
Its perpendicular orientation to, and spatial coincidence with the central
embedded powerful bipolar radio jet, provides the best evidence yet that
massive stars form via disk accretion in direct analogy to the formation of
low-mass stars
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