306 research outputs found
A Real-Time Comparison of Four Particulate Matter Size Fractions in the Personal Breathing Zone of Paris Subway Workers: A Six-Week Prospective Study.
We developed a Bayesian spline model for real-time mass concentrations of particulate matter (PM10, PM2.5, PM1, and PM0.3) measured simultaneously in the personal breathing zone of Parisian subway workers. The measurements were performed by GRIMM, a gravimetric method, and DiSCmini during the workers' work shifts over two consecutive weeks. The measured PM concentrations were analyzed with respect to the working environment, the underground station, and any specific events that occurred during the work shift. Overall, PM0.3 concentrations were more than an order of magnitude lower compared to the other PM concentrations and showed the highest temporal variation. The PM2.5 levels raised the highest exposure concern: 15 stations out of 37 had higher mass concentrations compared to the reference. Station PM levels were not correlated with the annual number of passengers entering the station, the year of station opening or renovation, or the number of platforms and tracks. The correlation with the number of station entrances was consistently negative for all PM sizes, whereas the number of correspondence concourses was negatively correlated with PM0.3 and PM10 levels and positively correlated with PM1 and PM2.5 levels. The highest PM10 exposure was observed for the station platform, followed by the subway cabin and train, while ticket counters had the highest PM0.3, PM1, and PM2.5 mass concentrations. We further found that compared to gravimetric and DiSCmini measurements, GRIMM results showed some discrepancies, with an underestimation of exposure levels. Therefore, we suggest using GRIMM, calibrated by gravimetric methods, for PM sizes above 1μm, and DiSCmini for sizes below 700 nm
The blue compact dwarf galaxy I Zw 18: a comparative study of its low-surface-brightness component
(abridged): Using HST and ground-based optical and NIR imaging data, we
investigate whether the blue compact dwarf (BCD) galaxy I Zw 18 possesses an
extended low-surface-brightness (LSB) old stellar population underlying its
star-forming (SF) regions. We show that the exponential intensity decrease
observed in the filamentary LSB envelope of the BCD out to 18 arcsec (1.3 kpc
at a distance of 15 Mpc) is not due to an evolved stellar disc, but rather due
to extended ionized gas emission. Broad-band images reveal, after subtraction
of nebular line emission, a compact stellar LSB component extending slightly
beyond the SF regions. This stellar host, being blue over a radius range of 5
exponential scale lengths and showing little colour contrast to the SF
component, differs strikingly from the red LSB host of standard BCDs. This
fact, in connection with the blue colors of component I Zw 18 C, suggests that
most of the stellar mass in I Zw 18 has formed within the last 0.5 Gyr.
Furthermore, we show that the exponential intensity fall-off in the filamentary
ionized envelope of I Zw 18 is not particular to this system but a common
property of the ionized halo of many SF dwarf galaxies on galactocentric
distances of several kpc. In the absence of an appreciable underlying stellar
background, extended ionized gas emission dominates in the periphery of I Zw
18, mimicking an exponential stellar disc on optical surface brightness
profiles.Comment: 24 pages, 16 figures; accepted for publication in Astronomy &
Astrophysics; higher resolution images available at
http://alpha.uni-sw.gwdg.de/~papade/IZw18
Karelian Seaside in a Linguistic Context
The current state of the study of Russian dialects in Karelian Seaside is analyzed, the territory of the studied region, which coincides with the boundaries of the dialectal division of the Russian language in 1915 is indicated. It is shown that the exclusion of Karelian Seaside from the dialectal division of 1965, which was an indirect reason for the lack of proper research attention to this region is unjustified. An overview of linguistic works devoted to the study of various language levels (phonetic, grammatical, lexical) is presented. The review of dictionaries, including the vocabulary of Russian dialects of the Karelian Seaside, is carried out. The prospects and objectives of the study are determined. In particular, future research is associated with comparative work on the study of the preservation / change of linguistic phenomena at each level, including the lexical one, which is the most stable in its main core. It is primarily due to extralinguistic reasons. Particular attention is paid to the use of digital technologies when creating a textual database, tested on the materials of the Karelian Seaside. It is noted that the electronic resource will make it possible to constantly introduce new data into scientific circulation, connecting them to various aspects of research, both linguistic and broader humanitarian
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Selective opposition-like control of large-scale structures in wall-bounded turbulence
Abstract: We investigate the effect of controlling large-scale, logarithmic-layer turbulent structures, which have a characteristic size and aspect ratio that scale with the distance from the wall. The aim is to quantify the effect of suppressing these structures while leaving the near-wall turbulent dynamics unaltered. By affecting only the logarithmic-layer structures, it might be possible to isolate their contribution to the drag from that of the other scales in the flow. We conduct direct numerical simulations of turbulent channel flows at friction Reynolds number ReT ?s 500-1000 and artificially remove certain streamwise and spanwise wavelengths of the wall-normal velocity across a range of heights. The wavelengths chosen depend on the target height (and size) of the structures that we wish to target. When these wavelengths are removed, we observe a positive, outward shift of the mean velocity profile above the target height, due to a local reduction in Reynolds shear stress, and a subsequent increase in viscous stress. Our preliminary results suggest that this shift in the mean velocity profile scales in outer units
Psychometric properties of burnout measures: a systematic review.
Occupational Burnout (OB) is currently measured through several Patient-Reported Outcome Measures (PROMs) and some of them have become widely used in occupational health research and practice. We, therefore, aimed to review and grade the psychometric validity of the five OB PROMs considered as valid for OB measure in mental health professionals (the Maslach Burnout Inventory (MBI), the Pines' Burnout Measure (BM), the Psychologist Burnout Inventory (PBI), the OLdenburg Burnout Inventory (OLBI) and the Copenhagen Burnout Inventory (CBI)).
We conducted systematic literature searches in MEDLINE, PsycINFO and EMBASE databases. We reviewed studies published between January 1980 and September 2018 following a methodological framework, in which each step of PROM validation, the reference method, analytical technics and result interpretation criteria were assessed. Using the COnsensus-based Standards for the selection of health Measurement Instruments we evaluated the risk of bias in studies assessing content and criterion validity, structural validity, internal consistency, reliability, measurement error, hypotheses testing and responsiveness of each PROM. Finally, we assessed the level of evidence for the validity of each PROM using the GRADE approach.
We identified 6541 studies, 19 of which were included for review. Fifteen studies dealt with MBI whereas BM, PBI, OLBI and CBI were each examined in only one study. OLBI had the most complete validation, followed by CBI, MBI, BM and PBI, respectively. When examining the result interpretation correctness, the strongest disagreement was observed for MBI (27% of results), BM (25%) and CBI (17%). There was no disagreement regarding PBI and OLBI. For OLBI and CBI, the quality of evidence for sufficient content validity, the crucial psychometric property, was moderate; for MBI, BM and PBI, it was very low.
To be validly and reliably used in medical research and practice, PROM should exhibit robust psychometric properties. Among the five PROMs reviewed, CBI and, to a lesser extent, OLBI meet this prerequisite. The cross-cultural validity of these PROMs was beyond the scope of our work and should be addressed in the future. Moreover, the development of a diagnostic standard for OB would be helpful to assess the sensitivity and specificity of the PROMs and further reexamine their validity.The study protocol was registered in PROSPERO (CRD 42019124621)
Assessing the inhaled dose of nanomaterials by nanoparticle tracking analysis (NTA) of exhaled breath condensate (EBC) and its relationship with lung inflammatory biomarkers.
The widespread and increasing use of nanomaterials has resulted in a higher likelihood of exposure by inhalation for nanotechnology workers. However, tracking the internal dose of nanoparticles deposited at the airways level, is still challenging. To assess the suitability of particle number concentration determination as biomarker of internal dose, we carried out a cross sectional investigation involving 80 workers handling nanomaterials. External exposure was characterized by portable counters of particles DISCminiTM (Testo, DE), allowing to categorize 51 workers as exposed and 29 as non-exposed (NE) to nanoparticles. Each subject filled in a questionnaire reporting working practices and health status. Exhaled breath condensate was collected and analysed for the number of particles/ml as well as for inflammatory biomarkers. A clear-cut relationship between the number of airborne particles in the nano-size range determined by the particle counters and the particle concentration in exhaled breath condensate (EBC) was apparent. Moreover, inflammatory cytokines (IL-1β, IL-10, and TNF-α) measured in EBC, were significantly higher in the exposed subjects as compared to not exposed. Finally, significant correlations were found between external exposure, the number concentration of particles measured by the nanoparticle tracking analysis (NTA) and inflammatory cytokines. As a whole, the present study, suggests that NTA can be regarded as a reliable tool to assess the inhaled dose of particles and that this dose can effectively elicit inflammatory effects
First look with JWST spectroscopy: galaxies resemble local analogues
Deep images and near-IR spectra of galaxies in the field of the lensing
cluster SMACS J0723.3-7327 were recently taken in the Early Release
Observations program of JWST. Among these, two NIRSpec spectra of galaxies at
and one at were obtained, revealing for the first time
rest-frame optical emission line spectra of galaxies in the epoch of
reionization, including the detection of the important[OIII]4363 auroral line
(see JWST PR 2022-035). We present an analysis of the emission line properties
of these galaxies, finding that these galaxies have a high excitation (as
indicated by high ratios of [OIII]/[OII], [NeIII]/[OII]), strong
[OIII]4363/H, high equivalent widths, and other properties which are
typical of low-metallicity star-forming galaxies. Using the direct method we
determine oxygen abundances of in two galaxies, and
a lower metallicity of in the galaxy
using different strong line methods. More accurate metallicity determinations
will require better data. With stellar masses estimated from SED fits, we find
that the three galaxies lie close to or below the mass-metallicity
relation. Overall, these first galaxy spectra at show a strong
resemblance of the emission lines properties of galaxies in the epoch of
reionization with those of relatively rare local analogues previously studied
from the SDSS. Clearly, the first JWST observations demonstrate already the
incredible power of spectroscopy to reveal properties of galaxies in the early
Universe.Comment: 6 pages, 6 Figures. Accepted for publication in Astronomy &
Astrophysics Letter
Broad Line Emission in Low-Metallicity Blue Compact Dwarf Galaxies: Evidence for Stellar Wind, Supernova and Possible AGN Activity
We present spectra of a large sample of low-metallicity blue compact dwarf
galaxies which exhibit broad components in their strong emission lines, mainly
in Hbeta, [O III]4959, 5007 and Halpha. Twenty-three spectra have been obtained
with the MMT, 14 of which show broad emission. The remaining 21 spectra with
broad emission have been selected from the Data Release 5 of the Sloan Digital
Sky Survey. The most plausible origin of broad line emission is the evolution
of massive stars and their interaction with the circumstellar and interstellar
medium. The broad emission with the lowest H luminosities (10^36 -
10^39 erg/s) is likely produced in circumstellar envelopes around hot Ofp/WN9
and/or LBV stars. The broad emission with the highest Halpha luminosities
(10^40 - 10^42 erg/s) probably arises from type IIp or type IIn supernovae
(SNe). It can also come from active galactic nuclei (AGN) containing
intermediate-mass black holes, although we find no strong evidence for hard
non-thermal radiation in our sample galaxies. The oxygen abundance in the host
galaxies with SN candidates is low and varies in the range 12 + log O/H = 7.36
- 8.31. However, type IIn SN / AGN candidates are found only in galaxies with
12 + log O/H < 7.99. Spectroscopic monitoring of these type IIn SN / AGN
candidates over a time scale of several years is necessary to distinguish
between the two possibilities.Comment: 50 pages, 6 figures. Accepted for publication in the Astrophysical
Journa
The Effect of pre-incubation duration of soil-biochar model mixtures on the results of determination the intensity of substrate-induced respiration (Methodological aspects of study)
Was studied in laboratory experiments the effect of short term (3 days) and long term (95 and 187 days) pre-incubation of soil-biochar model mixes (ratio 20:1) in optimal conditions for the microorganisms on the results of definition the intensity of substrate induced respiration. For experiments 10 biochar samples were used. The biochars were produced from the woody and herbaceous materials under different pyrolysis conditions. Is revealed the heterogeneous influence of biochar by direction and dynamics on the rate of substrate induced respiration depending on the pre-incubation time of model mixtures. It is shown that the prolonged pre-incubation of biochar with soil material under optimal levels of moisture and temperature is a prerequisite for the correct formulation of laboratory experiments and provides a reliable assessment of the impact of biochar on a soil respiration. We can recommend the duration of pre-incubation 3-5 months
Associating Air Pollution with Cytokinesis-Block Micronucleus Assay Parameters in Lymphocytes of the General Population in Zagreb (Croatia).
Air pollution is recognized as one of the most serious public health issues worldwide and was declared to be a leading environmental cause of cancer deaths. At the same time, the cytokinesis-block micronucleus (CBMN) assay serves as a cancer predictive method that is extensively used in human biomonitoring for populations exposed to environmental contamination. The objective of this cross-sectional study is two-fold: to evaluate genomic instability in a sample (N = 130) of healthy, general population residents from Zagreb (Croatia), chronically exposed to different levels of air pollution, and to relate them to air pollution levels in the period from 2011 to 2015. Measured frequencies of CBMN assay parameters were in agreement with the baseline data for the general population of Croatia. Air pollution exposure was based on four factors obtained from a factor analysis of all exposure data obtained for the examined period. Based on the statistical results, we did not observe a significant positive association between any of the CBMN assay parameters tested and measured air pollution parameters for designated time windows, except for benzo(a)pyrene (B[a]P) that showed significant negative association. Our results show that measured air pollution parameters are largely below the regulatory limits, except for B[a]P, and as such, they do not affect CBMN assay parameters' frequency. Nevertheless, as air pollution is identified as a major health threat, it is necessary to conduct prospective studies investigating the effect of air pollution on genome integrity and human health
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