3,805 research outputs found
The association between tobacco and the risk of asthma, rhinoconjunctivitis and eczema in children and adolescents : analyses from Phase Three of the ISAAC programme
We are grateful to the children and parents who participated
in ISAAC Phase Three and the coordination and assistance by the school staff is
sincerely appreciated. The authors also acknowledge and thank the many funding
bodies throughout the world that supported the individual ISAAC centres and
collaborators and their meetings.Background: Exposure to parental smoking is associated
with wheeze in early childhood, but in 2006 the US
Surgeon General stated that the evidence is insufficient
to infer a causal relationship between exposure and
asthma in childhood and adolescents.
Aims:To examine the association between maternal and
paternal smoking and symptoms of asthma, eczema and
rhinoconjunctivitis.
Methods: Parents or guardians of children aged
6-7 years completed written questionnaires about
symptoms of asthma, rhinoconjunctivitis and eczema,
and several risk factors, including maternal smoking in
the child’s first year of life, current maternal smoking
(and amount) and paternal smoking. Adolescents aged
13-14 years self completed the questionnaires on these
symptoms and whether their parents currently smoked.
Results: In the 6-7-year age group there were 220 407
children from 75 centres in 32 countries. In the 13-14-
year age group there were 350 654 adolescents from
118 centres in 53 countries. Maternal and paternal
smoking was associated with an increased risk of
symptoms of asthma, eczema and rhinoconjunctivitis in
both age groups, although the magnitude of the OR is
higher for symptoms of asthma than the other outcomes.
Maternal smoking is associated with higher ORs than
paternal smoking. For asthma symptoms there is a clear
dose relationship (1e9 cigarettes/day, OR 1.27; 10-19
cigarettes/day, OR 1.35; and 20+ cigarettes/day, OR
1.56). When maternal smoking in the child’s first year of
life and current maternal smoking are considered, the
main effect is due to maternal smoking in the child’s first
year of life. There was no interaction between maternal
and paternal smoking.
Conclusions: This study has confirmed the importance
of maternal smoking, and the separate and additional
effect of paternal smoking. The presence of
a dose-response effect relationship with asthma
symptoms suggests that the relationship is causal,
however for eczema and rhinoconjunctivitis causality is
less certain.peer-reviewe
Potential Distribution of Six North American Higher-Attine Fungus-Farming Ant (Hymenoptera: Formicidae) Species
Ants are among the most successful insects in Earth’s evolutionary history. However, there is a lack of knowledge regarding range-limiting factors that may influence their distribution. The goal of this study was to describe the environmental factors (climate and soil types) that likely impact the ranges of five out of the eight most abundant Trachymyrmex species and the most abundant Mycetomoellerius species in the United States. Important environmental factors may allow us to better understand each species’ evolutionary history. We generated habitat suitability maps using MaxEnt for each species and identified associated most important environmental variables. We quantified niche overlap between species and evaluated possible congruence in species distribution. In all but one model, climate variables were more important than soil variables. The distribution of M. turrifex (Wheeler, W.M., 1903) was predicted by temperature, specifically annual mean temperature (BIO1), T. arizonensis (Wheeler, W.M., 1907), T. carinatus, and T. smithi Buren, 1944 were predicted by precipitation seasonality (BIO15), T. septentrionalis (McCook, 1881) were predicted by precipitation of coldest quarter (BIO19), and T. desertorum (Wheeler, W.M., 1911) was predicted by annual flood frequency. Out of 15 possible pair-wise comparisons between each species’ distributions, only one was statistically indistinguishable (T. desertorum vs T. septentrionalis). All other species distribution comparisons show significant differences between species. These models support the hypothesis that climate is a limiting factor in each species distribution and that these species have adapted to temperatures and water availability differently
ASCA and contemporaneous ground-based observations of the BL Lacertae objects 1749+096 and 2200+420 (BL Lac)
We present ASCA observations of the radio-selected BL Lacertae objects
1749+096 (z=0.32) and 2200+420 (BL Lac, z=0.069) performed in 1995 Sept and
Nov, respectively. The ASCA spectra of both sources can be described as a first
approximation by a power law with photon index Gamma ~ 2. This is flatter than
for most X-ray-selected BL Lacs observed with ASCA, in agreement with the
predictions of current blazar unification models. While 1749+096 exhibits
tentative evidence for spectral flattening at low energies, a concave continuum
is detected for 2200+420: the steep low-energy component is consistent the
high-energy tail of the synchrotron emission responsible for the longer
wavelengths, while the harder tail at higher energies is the onset of the
Compton component. The spectral energy distributions from radio to gamma-rays
are consistent with synchrotron-self Compton emission from a single homogeneous
region shortward of the IR/optical wavelengths, with a second component in the
radio domain related to a more extended emission region. For 2200+420,
comparing the 1995 Nov state with the optical/GeV flare of 1997 July, we find
that models requiring inverse Compton scattering of external photons provide a
viable mechanism for the production of the highest (GeV) energies during the
flare. An increase of the external radiation density and of the power injected
in the jet can reproduce the flat gamma-ray continuum observed in 1997 July. A
directly testable prediction of this model is that the line luminosity in
2200+420 should vary shortly after (~1 month) a non-thermal synchrotron flare.Comment: 28 pages,6 figures, 5 tables; LaTeX document. accepted for
publication in the Astrophysical Journa
Implementing clinical trial data sharing requires training a new generation of biomedical researchers
Data sharing enhances the value of medical research and builds trust in clinical trials, but more biomedical researchers need to be trained in these approaches, which include meta-research, data science and ethical, legal and social issues
Fundamental constants and tests of theory in Rydberg states of hydrogen-like ions
Comparison of precision frequency measurements to quantum electrodynamics
(QED) predictions for Rydberg states of hydrogen-like ions can yield
information on values of fundamental constants and test theory. With the
results of a calculation of a key QED contribution reported here, the
uncertainty in the theory of the energy levels is reduced to a level where such
a comparison can yield an improved value of the Rydberg constant.Comment: 4 pages, RevTe
Environmentally and behaviourally mediated co-occurrence of functional traits in bird communities of tropical forest fragments
Two major theories of community assembly - based on the assumption of limiting similarity' or 'habitat filtering', respectively - predict contrasting patterns in the spatial arrangement of functional traits. Previous analyses have made progress in testing these predictions and identifying underlying processes, but have also pointed to theoretical as well as methodological shortcomings. Here we applied a recently developed methodology for spatially explicit analysis of phylogenetic meta-community structure to study the pattern of co-occurrence of functional traits in Afrotropical and Neotropical bird species inhabiting forest fragments. Focusing separately on locomotory, dietary, and dispersal traits, we tested whether environmental filtering causes spatial clustering, or competition leads to spatial segregation as predicted by limiting similarity theory. We detected significant segregation of species co-occurrences in African fragments, but not in the Neotropical ones. Interspecific competition had a higher impact on trait co-occurrence than filter effects, yet no single functional trait was able to explain the observed degree of spatial segregation among species. Despite high regional variability spanning from spatial segregation to aggregation, we found a consistent tendency for a clustered spatial patterning of functional traits among communities in fragmented landscapes, particularly in non-territorial species. Overall, we show that behavioural effects, such as territoriality, and environmental effects, such as the area of forest remnants or properties of the landscape matrix in which they are embedded, can strongly affect the pattern of trait co-occurrence. Our findings suggest that trait-based analyses of community structure should include behavioural and environmental covariates, and we here provide an appropriate method for linking functional traits, species ecology and environmental conditions to clarify the drivers underlying spatial patterns of species co-occurrence
Brief Report: The Value of a Patient Global Assessment of Disease Activity in Granulomatosis With Polyangiitis (Wegener's)
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102695/1/art38248.pd
Recommended from our members
Beyond words: Aesthetic knowledge and knowing in design
Aesthetic knowledge comes from practitioners understanding the look, feel, smell, taste and sound of things. It is vital to work in many organizational contexts. In this paper, we explore aesthetic knowledge and knowing in organizations through detailed observation of design work in the architectural practice Edward Cullinan Architects. Through our research, we explore aesthetic knowledge in the context of architectural work, we unpack what it is, how it is generated, and how it is applied in design projects, shared between practitioners and developed at the level of the organization. Our analysis suggests that aesthetic knowledge plays an important part in organizational practice, not only as the symbolic context for work, but as an integral part of the work that people do. It suggests that aesthetic reflexivity, which involves an opening up and questioning of what is known, is experienced as part of practice as well as a `time out' from practice
Designing physical activity environments to accrue physical and psychological effects
Understanding how best to accrue benefits from designing physical activity and exercise programmes is needed to tackle global health problems related to physical inactivity and poor mental health. Some studies have implicated an important role for green exercise and physical activity, but there is a lack of clarity in current research. Therefore, more work is needed to understand how to design green physical activity and exercise environments that afford (invite) physical and psychological benefits to individuals. We examined whether exercising while viewing a dynamic or static image of a scene from nature would offer different affordances (invitations for behaviours to emerge), compared to the common conditions of self-selected entertainment. For this purpose, 30 participants (18 males and 12 females; age 27.5 ± 9 yrs; mass 67.6 ± 11.1 kg; stature 173.7 ± 8.2 cm) exercised in three experimental conditions in a counterbalanced design while: (i) viewing a video of a green environment, (ii) viewing a single static image of the green environment; and (iii), when using typical self-selected entertainment without viewing images of nature. A twenty-minute treadmill run was undertaken at the participants’ own self-selected speed in a laboratory while energy expenditure and psychological states (using PANAS) were assessed. Results showed no differences in energy expenditure (p > .05) or negative affect (p > .05) between conditions. However, data revealed significant differences in positive affect when participants ran with a static image and their own entertainment compared to running with a dynamic image. Results revealed how differences in affordances designed into physical activity environments can shape psychological states that emerge during exercise. Further research is needed on affordance design in physical activity and exercise by engineers, designers, planners and psychologists to explore effects of a range of simulated environments, with different target groups, such as fit and unfit individuals, elderly and children
- …