656 research outputs found
Combating CVD in Kazakhstan through workplace interventions
The project designs and tests a multifaceted worksite intervention protocol that includes
smoking cessation, dietary instruction, and exercise regimens to lower the prevalence of CVD morbidity
and mortality in Kazakhstan. Kazakhstan has among the highest CVD morbidity and mortality rates in
the world. Development of an effective worksite intervention model that targets and improves the health
behaviors and health status of high-risk middle age working males can be extended to the Republic's
crucial and expanding workplace environment
Combating CVD in Kazakhstan through workplace interventions
The project designs and tests a multifaceted worksite intervention protocol that includes
smoking cessation, dietary instruction, and exercise regimens to lower the prevalence of CVD morbidity
and mortality in Kazakhstan. Kazakhstan has among the highest CVD morbidity and mortality rates in
the world. Development of an effective worksite intervention model that targets and improves the health
behaviors and health status of high-risk middle age working males can be extended to the Republic's
crucial and expanding workplace environment
Light emission, light detection and strain sensing with nanocrystalline graphene
Graphene is of increasing interest for optoelectronic applications exploiting
light detection, light emission and light modulation. Intrinsically light
matter interaction in graphene is of a broadband type. However by integrating
graphene into optical micro cavities also narrow band light emitters and
detectors have been demonstrated. The devices benefit from the transparency,
conductivity and processability of the atomically thin material. To this end we
explore in this work the feasibility of replacing graphene by nanocrystalline
graphene, a material which can be grown on dielectric surfaces without catalyst
by graphitization of polymeric films. We have studied the formation of
nanocrystalline graphene on various substrates and under different
graphitization conditions. The samples were characterized by resistance,
optical transmission, Raman, X-ray photoelectron spectroscopy, atomic force
microscopy and electron microscopy measurements. The conducting and transparent
wafer-scale material with nanometer grain size was also patterned and
integrated into devices for studying light-matter interaction. The measurements
show that nanocrystalline graphene can be exploited as an incandescent emitter
and bolometric detector similar to crystalline graphene. Moreover the material
exhibits piezoresistive behavior which makes nanocrystalline graphene
interesting for transparent strain sensors
Risk factors associated with asbestos-related diseases: results of the asbestos surveillance programme Aachen
The aim of this study was to examine the association between workplace exposure to asbestos and risk factors for developing related chronic respiratory diseases, using the analysis of a cohort of 8,582 formerly asbestos-exposed workers, as well as to assess the grade value of three risk categories used for a focused surveillance procedure. The results showed that the participants who were aged over 65 (OR and 95% CI: 11.47 [5.48-23.99]) and active smokers (OR and 95% CI: 9.48 [4.07-22.09]), were at a significantly high risk for developing lung cancer. The risk of developing benign lesions of the lung or pleura (BLLP) was almost 6-times higher (OR and 95% CI: 5.76 [4.7-7]) for the age group over 65. The risk of developing mesothelioma was influenced by exposure duration (OR and 95% CI: 4.36 [1-19.01]); and for the age group over 65 (OR and 95% CI: 4.58 [1.86-11.27]). The study has demonstrated that the use of risk categories based on a combination of risk factors (age, smoking status, and duration of exposure) could be advantageous for planning the target health surveillance programmes
Effect of four plant species on soil 15N-access and herbage yield in temporary agricultural grasslands
Positive plant diversity-productivity relationships have been reported for experimental semi-natural grasslands (Cardinale et al. 2006; Hector et al. 1999; Tilman et al. 1996) as well as temporary agricultural grasslands (Frankow-Lindberg et al. 2009; Kirwan et al. 2007; Nyfeler et al. 2009; Picasso et al. 2008). Generally, these relationships are explained, on the one hand, by niche differentiation and facilitation (Hector et al. 2002; Tilman et al. 2002) and, on the other hand, by greater probability of including a highly productive plant species in high diversity plots (Huston 1997). Both explanations accept that diversity is significant because species differ in characteristics, such as root architecture, nutrient acquisition and water use efficiency, to name a few, resulting in composition and diversity being important for improved productivity and resource use (Naeem et al. 1994; Tilman et al. 2002). Plant diversity is generally low in temporary agricultural grasslands grown for ruminant fodder production. Grass in pure stands is common, but requires high nitrogen (N) inputs. In terms of N input, two-species grass-legume mixtures are more sustainable than grass in pure stands and consequently dominate low N input grasslands (Crews and Peoples 2004; Nyfeler et al. 2009; Nyfeler et al. 2011).
In temperate grasslands, N is often the limiting factor for productivity (Whitehead 1995). Plant available soil N is generally concentrated in the upper soil layers, but may leach to deeper layers, especially in grasslands that include legumes (Scherer-Lorenzen et al. 2003) and under conditions with surplus precipitation (Thorup-Kristensen 2006). To improve soil N use efficiency in temporary grasslands, we propose the addition of deep-rooting plant species to a mixture of perennial ryegrass and white clover, which are the most widespread forage plant species in temporary grasslands in a temperate climate (Moore 2003). Perennial ryegrass and white clover possess relatively shallow root systems (Kutschera and Lichtenegger 1982; Kutschera and Lichtenegger 1992) with effective rooting depths of <0.7 m on a silt loamy site (Pollock and Mead 2008). Grassland species, such as lucerne and chicory, grow their tap-roots into deep soil layers and exploit soil nutrients and water in soil layers that the commonly grown shallow-rooting grassland species cannot reach (Braun et al. 2010; Skinner 2008). Chicory grown as a catch crop after barley reduced the inorganic soil N down to 2.5 m depth during the growing season, while perennial ryegrass affected the inorganic soil N only down to 1 m depth (Thorup-Kristensen 2006). Further, on a Wakanui silt loam in New Zealand chicory extracted water down to 1.9 m and lucerne down to 2.3 m soil depth, which resulted in greater herbage yields compared with a perennial ryegrass-white clover mixture, especially for dryland plots (Brown et al. 2005).
There is little information on both the ability of deep- and shallow-rooting grassland species to access soil N from different vertical soil layers and the relation of soil N-access and herbage yield in temporary agricultural grasslands. Therefore, the objective of the present work was to test the hypotheses 1) that a mixture comprising both shallow- and deep-rooting plant species has greater herbage yields than a shallow-rooting binary mixture and pure stands, 2) that deep-rooting plant species (chicory and lucerne) are superior in accessing soil N from 1.2 m soil depth compared with shallow-rooting plant species, 3) that shallow-rooting plant species (perennial ryegrass and white clover) are superior in accessing soil N from 0.4 m soil depth compared with deep-rooting plant species, 4) that a mixture of deep- and shallow-rooting plant species has greater access to soil N from three soil layers compared with a shallow-rooting two-species mixture and that 5) the leguminous grassland plants, lucerne and white clover, have a strong impact on grassland N acquisition, because of their ability to derive N from the soil and the atmosphere
The Age-Redshift Relation for Standard Cosmology
We present compact, analytic expressions for the age-redshift relation
for standard Friedmann-Lema\^ \itre-Robertson-Walker (FLRW)
cosmology. The new expressions are given in terms of incomplete Legendre
elliptic integrals and evaluate much faster than by direct numerical
integration.Comment: 13 pages, 3 figure
Gamma-Ray Background from Structure Formation in the Intergalactic Medium
The universe is filled with a diffuse and isotropic extragalactic background
of gamma-ray radiation, containing roughly equal energy flux per decade in
photon energy between 3 MeV-100 GeV. The origin of this background is one of
the unsolved puzzles in cosmology. Less than a quarter of the gamma-ray flux
can be attributed to unresolved discrete sources, but the remainder appears to
constitute a truly diffuse background whose origin has hitherto been
mysterious. Here we show that the shock waves induced by gravity during the
formation of large-scale structure in the intergalactic medium, produce a
population of highly-relativistic electrons with a maximum Lorentz factor above
10^7. These electrons scatter a small fraction of the microwave background
photons in the present-day universe up to gamma-ray energies, thereby providing
the gamma-ray background. The predicted diffuse flux agrees with the observed
background over more than four decades in photon energy, and implies a mean
cosmological density of baryons which is consistent with Big-Bang
nucleosynthesis.Comment: 7 pages, 1 figure. Accepted for publication in Nature. (Press embargo
until published.
Managing risks to drivers in road transport
This report presents a number of case studies in managing risks to road transport drivers. The cases feature a variety of initiatives and interventions to protect drivers.In the road transport sector, as with any other, it is important to pay attention to working conditions in order to ensure a skilled and motivated workforce. Certain characteristics of the sector make it more difficult to practice risk management than in other sectors. But by taking account of how the sector operates in practice, and the characteristics of drivers themselves and the way they work, risks can be successfully manage
Spectral evolution of non-thermal electron distributions in intense radiation fields
(abridged) Models of many astrophysical gamma-ray sources assume they contain
a homogeneous distribution of electrons that are injected as a power-law in
energy and evolve by interacting with radiation fields, magnetic fields and
particles in the source and by escaping. This problem is particularly
complicated if the radiation fields have higher energy density than the
magnetic field and are sufficiently energetic that inverse Compton scattering
is not limited to the Thomson regime. We present a simple, time-dependent,
semi-analytical solution of the electron kinetic equation that treats both
continuous and impulsive injection, cooling via synchrotron and inverse Compton
radiation, (taking into account Klein-Nishina effects) and energy dependent
particle escape. The kinetic equation for an arbitrary, time-dependent source
function is solved by the method of Laplace transformations. Using an
approximate expression for the energy loss rate that takes into account
synchrotron and inverse Compton losses including Klein-Nishina effects for
scattering off an isotropic photon field with either a power-law or black-body
distribution, we find explicit expressions for the cooling time and escape
probability of individual electrons. This enables the full, time-dependent
solution to be reduced to a single quadrature. From the electron distribution,
we then construct the time-dependent, multi-wavelength emission spectrum. We
compare our solutions with several limiting cases and discuss the general
appearance and temporal behaviour of spectral features (i.e., cooling breaks,
bumps etc.). As a specific example, we model the broad-band energy spectrum of
the open stellar association Westerlund-2 at different times of its evolution,
and compare it with observations.Comment: 14 pages, 8 figures, acccepted for publication in A&
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