1,720,983 research outputs found
Physiological responses to acute airborne particle exposure during maximal aerobic power
No full textWe measured physiological effects of airborne particle exposure in athletes.\ud
Intensity exercise close to maximal aerobic capacity was considered.\ud
Particles were generated through incense-burning indoor phenomena.\ud
Statistically significant differences were found between high and low scenarios.\ud
No differences were measured in terms of exhaled nitric oxide
Aerosol deposition doses in the human respiratory tree of electronic cigarette smokers
No full textAerosols from eight e-cigarettes at different nicotine levels and flavoring were characterized as particle number size distributions in the range 5.6-560 nm by FMPS and CPC. Results were used to provide dosimetry estimates applying the MMPD model. Particle number concentrations varied between 3.26 Ã 109 and 4.09 Ã 109 part cm-3 for e-liquids without nicotine and between 5.08 Ã 109 and 5.29 Ã 109 part cm-3 for e-liquids with nicotine. No flavor effects were detected on particle concentration data. Particle size distributions were unimodal with modes between 107-165 nm and 165-255 nm, for number and volume metrics, respectively. Averagely, 6.25 Ã 1010 particles were deposited in respiratory tree after a single puff. Highest deposition densities and mean layer thickness of e-cigarette liquid on the lung epithelium were estimated at lobar bronchi. Our study shows that e-cigarette aerosol is source of high particle dose in respiratory system, from 23% to 35% of the daily dose of a no-smoking individual
Dimensional and chemical characterization of airborne particles in schools: Respiratory effects in children
No full textThis work reports the detailed characterization of child exposure to particles in three naturally-ventilated Italian schools. Two polluted urban schools and a rural one are considered in this study. Dimensional and chemical analyses of particles were performed by measuring particle number concentrations, particle size distributions, OC/BC concentrations and relative inorganic and organic fractions, both indoors and outdoors.\ud
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Respiratory function, exhaled Nitric Oxide (eNO) and Prick Skin tests were also performed on 75 children attending the three schools in order to evaluate the effects of such exposure on the children’s respiratory systems.\ud
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Exposure to particles at the urban schools was found higher than at the rural one, from both dimensional and chemical perspectives. Indoor particle number concentrations ranged from 1.95 × 104 to 3.49 × 104 part./cm3, whereas indoor black carbon concentrations varied between 1.9–13.9 μg/m3, with the lowest levels of both measured at the rural school.\ud
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In contrast to the dimensional and chemical results, the respiratory function and eNO test results were statistically similar among children attending all the three schools: the lung function values were within 20% of the European Community for Steel and Coal predicted ones, with the eNO data for healthy children ranging from 10.1 to 11.5 ppm. Medical outcomes indicate that these levels of school exposure did not significantly affect the children’s respiratory outcomes
Particle resuspension in school gyms during physical activities
No full textThe aim of this work was to quantify the exposure of children to particle resuspension in school gyms. In fact, although moderate standard aerobic activity is suggested for good health, adverse health effects could affect people exercising in micro-environments with ambient pollution. Overall, 12 micro-environments were chosen and analyzed in a 3-month experimental campaign. The different fractions of particulate matter (PM) were measured by means of photometers, calibrated for the specific aerosols studied through gravimetric samplers, whereas particle number distributions in the 0.5–20 μm range were continuously measured using an Aerodynamic Particle Sizer (APS) spectrometer. High PM concentration levels were measured in school gyms compared to outdoor values. The dominant source is the particle resuspension produced by the activity of exercising pupils and, among the various PM fractions, the effect on coarse particles (PM10–2.5) was found to be the most important, with the related emissions factors measured in the range of 1.5–8.9 mg/min. During school activities, under natural ventilation conditions, the average coarse particle concentrations at the 12 school gyms investigated were found to be 4.8 ± 2.0 times higher than the background (outdoor) values. The key parameters are the number and intensity of the physical activities, which can be characterized by the total energy used by the students. Therefore, this study provides useful data on the exposure of students to airborne particles during periods of physical activity in gyms with natural ventilation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Electronic cigarettes: age-specific generation-resolved pulmonary doses
No full textParticle size-number distributions of aerosol from e-cigarettes (0 and 14 mg mL−1nicotine) were compared with conventional cigarettes. Results were used to provide age-specific (9–21 years) dosimetry estimates applying the MMPD model. After a 2-s puff, total number doses (DTot) were highest for 9 years of age (6.01 × 1010–1.31 × 1011particles) and lowest for 18 years of age (4.69 × 1010–1.06 × 1011particles). Such doses represented about 19–45 and 25–100% of the relevant daily doses of not smoking individuals, respectively, in tracheobronchial (TB) and alveolar (A) regions. DTotfor the e-cigarettes were about double that for conventional cigarette. Deposition densities and daily volume of e-cigarette liquid deposited per unit surface area were maximum at lobar bronchi, highest for 9 years and lowest for 21 years age
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