17,905 research outputs found
Exposure to Dust and Endotoxin of Employees in Cucumber and Tomato Nurseries
Exposure to bioaerosols in occupational settings is associated with a range of adverse health effects. The aim of this study was to investigate the exposure levels to dust and endotoxin of people working in two cucumber nurseries and two tomato nurseries. Exposure was measured for greenhouse workers (n = 70) mainly working on harvesting cucumbers and tomatoes and clearing the plants after the harvest season. The people were exposed to between 0.2 and 15 mg inhalable dust m−3 (median = 1.6 mg m−3) and between 0.5 and 400 ng inhalable endotoxin m−3 (median = 32 ng m−3). The exposure to ‘total dust’ and endotoxin measured by stationary samplers (n = 30) in the greenhouses was low. Endotoxin was present in relatively high concentrations on cucumber leaves compared with leaves on pot plants. The Danish occupational exposure limit (OEL) for total organic dust is 3 mg m−3 and 36% and 17% of the cucumber and tomato workers, respectively, were exposed to >3.0 mg inhalable dust m−3. There is no OEL for endotoxin, but ‘no effect levels’ at ∼15 ng m−3 have been found. The majority of subjects (65%) were exposed to >15 ng m−3. Significantly higher exposure was found for employees in cucumber nurseries than for employees in tomato nurseries. Clearing tomato plants after the harvest season caused a higher exposure to endotoxin than tomato harvesting. In conclusion, people working in cucumber and tomato nurseries were often exposed to high levels of inhalable dust and endotoxin. Cucumber harvest workers were exposed to significantly more dust and endotoxin than tomato harvest workers. The dust and endotoxin aerosolized during the working processes were only transported to other areas in the greenhouses to a very low degree. Cucumber and tomato leaves were identified as endotoxin reservoirs
Interaction between superconducting vortices and Bloch wall in ferrite garnet film
Interaction between a Bloch wall in a ferrite-garnet film and a vortex in a
superconductor is analyzed in the London approximation. Equilibrium
distribution of vortices formed around the Bloch wall is calculated. The
results agree quantitatively with magneto-optical experiment where an in-plane
magnetized ferrite-garnet film placed on top of NbSe2 superconductor allows
observation of individual vortices. In particular, our model can reproduce a
counter-intuitive attraction observed between vortices and a Bloch wall having
the opposite polarity. It is explained by magnetic charges appearing due to
discontinuity of the in-plane magnetization across the wall.Comment: 4 pages, 5 figure
Onset of dendritic flux avalanches in superconducting films
We report a detailed comparison of experimental data and theoretical
predictions for the dendritic flux instability, believed to be a generic
behavior of type-II superconducting films. It is shown that a thermo-magnetic
model published very recently [Phys. Rev. B 73, 014512 (2006)] gives an
excellent quantitative description of key features like the instability onset
(first dendrite appearance) magnetic field, and how the onset field depends on
both temperature and sample size. The measurements were made using
magneto-optical imaging on a series of different strip-shaped samples of MgB2.
Excellent agreement is also obtained by reanalyzing data previously published
for Nb.Comment: 4 pages, 5 figure
Aesthetics and literature : a problematic relation?
The paper argues that there is a proper place for literature within aesthetics but that care must be taken in identifying just what the relation is. In characterising aesthetic pleasure associated with literature it is all too easy to fall into reductive accounts, for example, of literature as merely "fine writing". Belleslettrist or formalistic accounts of literature are rejected, as are two other kinds of reduction, to pure meaning properties and to a kind of narrative realism. The idea is developed that literature-both poetry and prose fiction-invites its own distinctive kind of aesthetic appreciation which far from being at odds with critical practice, in fact chimes well with it
Deriving main field and secular variation models from synthetic Swarm satellite and observatory data
The Dendritic magnetic avalanches in carbon-free MgB thin films with and without a deposited Au layer
From the magneto optics images (MOI), the dendritic magnetic avalanche is
known to appear dominantly for thin films of the newly discovered MgB. To
clarify the origin of this phenomenon, we studied in detail the MOI of
carbon-free MgB thin films with and without a deposited gold layer. The MOI
indicated carbon contamination was not the main source of the avalanche. The
MOI clearly showed that the deposition of metallic gold deposition on top of a
MgB thin film improved its thermal stability and suppressed the sudden
appearance of the dendritic flux avalanche. This is consistent with the
previous observation of flux noise in the magnetization.Comment: 9 pages, 4 figeure
Prescription patterns of benzodiazepine and benzodiazepine-related drugs in the peripartum period: A population-based study
Using prescription drugs during pregnancy is challenging and approached with caution. In this study, we present population-based information on prescription patterns of benzodiazepines and benzodiazepine-related drugs in the peripartum period. A population-based study of 1,154,817 pregnancies between 1997 and 2015 in Denmark, of which 205,406 (17.8%) pregnancies in women with a psychiatric history. Prescription drugs starting with Anatomical Therapeutic Chemical codes N05BA, N05CD, and N05CF from 12 months before pregnancy to 12 months following pregnancy were identified. We used generalised estimating equations to estimate the adjusted 5 year risk difference in the proportion of women redeeming benzodiazepines from 1 year to 5 years after. Logistic regression was used to analyze the association between characteristics and discontinuation of benzodiazepines during pregnancy. The prevalence of benzodiazepine prescriptions was 1.9% before pregnancy, 0.6% during pregnancy, and 1.3% after pregnancy. In women with a psychiatric history, the prevalence was 5–6 times higher. A significant decrease in prescriptions to women with a psychiatric history was observed, which was less profound among women with no psychiatric history. Approximately 90% of women discontinue benzodiazepines during pregnancy, with a higher percentage of women discontinuing from 1997 to 2015. The observed decrease is likely explained by changing treatment guidelines
Homology and K--Theory Methods for Classes of Branes Wrapping Nontrivial Cycles
We apply some methods of homology and K-theory to special classes of branes
wrapping homologically nontrivial cycles. We treat the classification of
four-geometries in terms of compact stabilizers (by analogy with Thurston's
classification of three-geometries) and derive the K-amenability of Lie groups
associated with locally symmetric spaces listed in this case. More complicated
examples of T-duality and topology change from fluxes are also considered. We
analyse D-branes and fluxes in type II string theory on with torsion flux and demonstrate in details
the conjectured T-duality to with no flux. In the
simple case of , T-dualizing the circles reduces to
duality between with
flux and with no flux.Comment: 27 pages, tex file, no figure
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