1,903 research outputs found
Isentropic Equation of State of Two-Flavour QCD in a Quasi-Particle Model
We examine the isentropic QCD equation of state within a quasi-particle model
being adjusted to first principle QCD calculations of two quark flavours. In
particular, we compare with Taylor expansion coefficients of energy and entropy
densities and with the isentropic trajectories describing the hydrodynamical
expansion of a heavy-ion collision fireball.Comment: Aug. 2006. 6pp. Invited talk given at International Workshop on Hot
and Dense Matter in Relativistic Heavy Ion Collisions, Budapest, Hungary,
9-12 Apr 200
VOLUNTARY REVELATION OF THE DEMAND FOR PUBLIC GOODS USING A PROVISION POINT MECHANISM
public goods, voluntary contributions, provision point, experiments, information, group size, Resource /Energy Economics and Policy, H41, C92,
Ultracold Chemistry and its Reaction Kinetics
We study the reaction kinetics of chemical processes occurring in the
ultracold regime and systematically investigate their dynamics. Quantum
entanglement is found to play a key role in driving an ultracold reaction
towards a dynamical equilibrium. In case of multiple concurrent reactions
Hamiltonian chaos dominates the phase space dynamics in the mean field
approximation.Comment: 15 pages, 5 figure
Particulate matter (PM) 2.5 levels in ETS emissions of a Marlboro Red cigarette in comparison to the 3R4F reference cigarette under open- and closed-door condition
Introduction: Potential health damage by environmental emission of tobacco smoke (environmental tobacco smoke, ETS) has been demonstrated convincingly in numerous studies. People, especially children, are still exposed to ETS in the small space of private cars. Although major amounts of toxic compounds from ETS are likely transported into the distal lung via particulate matter (PM), few studies have quantified the amount of PM in ETS. Study aim The aim of this study was to determine the ETS-dependent concentration of PM from both a 3R4F reference cigarette (RC) as well as a Marlboro Red brand cigarette (MRC) in a small enclosed space under different conditions of ventilation to model car exposure.
Method: In order to create ETS reproducibly, an emitter (ETSE) was constructed and mounted on to an outdoor telephone booth with an inner volume of 1.75 m3. Cigarettes were smoked under open- and closed-door condition to imitate different ventilation scenarios. PM2.5 concentration was quantified by a laser aerosol spectrometer (Grimm; Model 1.109), and data were adjusted for baseline values. Simultaneously indoor and outdoor climate parameters were recorded. The time of smoking was divided into the ETS generation phase (subset "emission") and a declining phase of PM concentration (subset "elimination"); measurement was terminated after 10 min. For all three time periods the average concentration of PM2.5 (Cmean-PM2.5) and the area under the PM2.5 concentration curve (AUC-PM2.5) was calculated. The maximum concentration (Cmax-PM2.5) was taken from the total interval.
Results: For both cigarette types open-door ventilation reduced the AUC-PM2.5 (RC: from 59 400 +/- 14 600 to 5 550 +/- 3 900 mug*sec/m3; MRC: from 86 500 +/- 32 000 to 7 300 +/- 2 400 mug*sec/m3; p < 0.001) and Cmean-PM2.5 (RC: from 600 +/- 150 to 56 +/- 40 mug/m3, MRC from 870 +/- 320 to 75 +/- 25 mug/m3; p < 0.001) by about 90%. Cmax-PM2.5 was reduced by about 80% (RC: from 1 050 +/- 230 to 185 +/- 125 mug/m3; MRC: from 1 560 +/-500 mug/m3 to 250 +/- 85 mug/m3; p < 0.001). In the subset "emission" we identified a 78% decrease in AUC-PM2.5 (RC: from 18 600 +/- 4 600 to 4 000 +/- 2 600 mug*sec/m3; MRC: from 26 600 +/- 7 200 to 5 800 +/- 1 700 mug*sec/m3; p < 0.001) and Cmean-PM2.5 (RC: from 430 +/- 108 to 93 +/- 60 mug/m3; MRC: from 620 +/- 170 to 134 +/- 40 mug/m3; p < 0.001). In the subset "elimination" we found a reduction of about 96-98% for AUC-PM2.5 (RC: from 40 800 +/- 11 100 to 1 500 +/- 1 700 mug*sec/m3; MRC: from 58 500 +/- 25 200 to 1 400 +/- 800 mug*sec/m3; p < 0.001) and Cmean-PM2.5 (RC: from 730 +/- 200 to 27 +/- 29 mug/m3; MRC: from 1 000 +/- 450 to 26 +/- 15 mug/m3; p < 0.001). Throughout the total interval Cmax-PM2.5 of MRC was about 50% higher (1 550 +/- 500 mug/m3) compared to RC (1 050 +/- 230 mug/m3; p < 0.05). For the subset "emission" - but not for the other periods - AUC-PM2.5 for MRC was 43% higher (MRC: 26 600 +/- 7 200 mug*sec/m3; RC: 18 600 +/- 4 600 mug*sec/m3; p < 0.05) and 44% higher for Cmean-PM2.5 (MRC: 620 +/- 170 mug/m3; RC: 430 +/- 108 mug/m3; p < 0.05).
Conclusion: This method allows reliable quantification of PM2.5-ETS exposure under various conditions, and may be useful for ETS risk assessment in realistic exposure situations. The findings demonstrate that open-door condition does not completely remove ETS from a defined indoor space of 1.75 m3. Because there is no safe level of ETS exposure ventilation is not adequate enough to prevent ETS exposure in confined spaces, e.g. private cars. Additionally, differences in the characteristics of cigarettes affect the amount of ETS particle emission and need to be clarified by ongoing investigations
Quantum yield optimized fluorophores for site-specific labeling and super-resolution imaging
Single molecule applications, saturated pattern excitation microscopy, or
stimulated emission depletion (STED) microscopy demand for bright and highly
stable fluorescent dyes1,2. Despite of intensive research the choice of
fluorphores is still very limited. Typically a stable fluorescent dyes is
covalently attached to the target. This methodology brings forward a number of
limitations, in particular, in case of protein labeling. First of all the
fluorescent probes need to be attached selectively and site-specifically to
prevent unspecific background. This often requires single cysteine mutations
for covalent protein modification. Employing quantum dots allows overcoming
problems of photo-bleaching3-6. However, the downsides are their large size,
rendering the probe inaccessible to spatially confined architectures, issues in
biocompatibility due to proper particle coating, and cellular toxicity6-8. Here
we propose a new method to overcome the above outlined problems
Real-time determination of laser beam quality by modal decomposition
We present a real-time method to determine the beam propagation ratio M2 of
laser beams. The all-optical measurement of modal amplitudes yields M2
parameters conform to the ISO standard method. The experimental technique is
simple and fast, which allows to investigate laser beams under conditions
inaccessible to other methods.Comment: 8 pages, 4 figures, published in Optics Expres
Validity and invariance of Turker’s corporate social responsibility scale in five cross-cultural samples
As organizational research turned its focus to Corporate Social Responsibility (CSR), interest also grew in the individual’s perspective on CSR. When looking for cross-cultural comparisons of the effects of CSR, measurement invariance is of utter importance as a questionnaire might not be equivalent in all investigated samples and thus bias results. We examined a previously published questionnaire assessing different aspects of personal CSR ratings. Factorial validity and measurement invariance was tested by means of confirmatory factor analysis and Bayesian structural equation modeling in five samples (total N = 1120): 2 US-American, 2 German, and 1 English-speaking Indian sample. In an exploratory-confirmatory approach, the originally proposed factor structure was altered to finally comprise four facets of CSR: employee-related CSR, environmental CSR, philanthropy and customer-related CSR. Measurement invariance tests showed evidence for small differences of the English and German version as well as significant divergences of the measurement model in the Indian sample. In conclusion, we show the validity of the questionnaire for a circumscribed Western context but are hesitant about further transfers. Future research on perception of CSR in non-western contexts might depend on new and tailored questionnaires
Consumer protection on Kickstarter
This article investigates consumer protection on Kickstarter—a popular and sizeable, yet largely unregulated reward-based crowdfunding platform. Specifically, the article focuses on Kickstarter campaigns’ use of price advertising claims (PACs) and their failure to honor the promised discounts. Analyses show that between 2009 and 2016, more than 500,000 consumers who backed a wide variety of game or technology campaigns lost on average $45.72 because of broken PAC promises. Whereas 75% of PAC campaigns did not provide the promised discounts, in almost 50% of all cases backers who were promised a discount paid more, not less, than the retail price. In contrast, backers of campaigns that did not promise a discount received larger effective discounts. Analyzing an extensive data set comprising 34,745 Kickstarter campaigns, complete backing histories of more than 400,000 backers, and more than 4 million consumer comments, complaints, and reviews, we show that broken PAC promises pose a substantial problem to consumers, that the problem is persistent across more than 6 years, and that it has not been resolved through self-regulation by market participants thus far
Partial Measurement Invariance: Extending and Evaluating the Cluster Approach for Identifying Anchor Items
When measurement invariance does not hold, researchers aim for partial measurement invariance by identifying anchor items that are assumed to be measurement invariant. In this paper, we build on Bechger and Maris’s approach for identification of anchor items. Instead of identifying differential item functioning (DIF)-free items, they propose to identify different sets of items that are invariant in item parameters within the same item set. We extend their approach by an additional step in order to allow for identification of homogeneously functioning item sets. We evaluate the performance of the extended cluster approach under various conditions and compare its performance to that of previous approaches, that are the equal-mean difficulty (EMD) approach and the iterative forward approach. We show that the EMD and the iterative forward approaches perform well in conditions with balanced DIF or when DIF is small. In conditions with large and unbalanced DIF, they fail to recover the true group mean differences. With appropriate threshold settings, the cluster approach identified a cluster that resulted in unbiased mean difference estimates in all conditions. Compared to previous approaches, the cluster approach allows for a variety of different assumptions as well as for depicting the uncertainty in the results that stem from the choice of the assumption. Using a real data set, we illustrate how the assumptions of the previous approaches may be incorporated in the cluster approach and how the chosen assumption impacts the results
Using One-Dimensional Compaction for Smaller Graph Drawings
We review the technique of one-dimensional compaction and use it as part of two new methods tackling problems in the context of automatic diagram layout: First, a postprocessing of the layer-based layout algorithm, also known as Sugiyama layout, and second a placement algorithm for connected components with external extensions. We apply our methods to dataflow diagrams from practical applications and find that the first method significantly reduces the width of left-to-right drawn diagrams. The second method allows to properly arrange disconnected graphs that have hierarchycrossing edges. Keywords: one-dimensional compaction, diagram layout, layer-based layout, Sugiyama layout, disconnected graphs, dataflow diagram
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