6,356 research outputs found
Impact of a smoking ban in hospitality venues on second hand smoke exposure : a comparison of exposure assessment methods
In May 2010, Switzerland introduced a heterogeneous smoking ban in the hospitality sector. While the law leaves room for exceptions in some cantons, it is comprehensive in others. This longitudinal study uses different measurement methods to examine airborne nicotine levels in hospitality venues and the level of personal exposure of non-smoking hospitality workers before and after implementation of the law.; Personal exposure to second hand smoke (SHS) was measured by three different methods. We compared a passive sampler called MoNIC (Monitor of NICotine) badge, to salivary cotinine and nicotine concentration as well as questionnaire data. Badges allowed the number of passively smoked cigarettes to be estimated. They were placed at the venues as well as distributed to the participants for personal measurements. To assess personal exposure at work, a time-weighted average of the workplace badge measurements was calculated.; Prior to the ban, smoke-exposed hospitality venues yielded a mean badge value of 4.48 (95%-CI: 3.7 to 5.25; nâ=â214) cigarette equivalents/day. At follow-up, measurements in venues that had implemented a smoking ban significantly declined to an average of 0.31 (0.17 to 0.45; nâ=â37) (pâ=â0.001). Personal badge measurements also significantly decreased from an average of 2.18 (1.31-3.05 nâ=â53) to 0.25 (0.13-0.36; nâ=â41) (pâ=â0.001). Spearman rank correlations between badge exposure measures and salivary measures were small to moderate (0.3 at maximum).; Nicotine levels significantly decreased in all types of hospitality venues after implementation of the smoking ban. In-depth analyses demonstrated that a time-weighted average of the workplace badge measurements represented typical personal SHS exposure at work more reliably than personal exposure measures such as salivary cotinine and nicotine
Moment tensor inversions of icequakes on Gornergletscher, Switzerland
We have determined seismic source mechanisms for shallow and intermediate-depth icequake clusters recorded on the glacier Gornergletscher, Switzerland, during the summers of 2004 and 2006. The selected seismic events are part of a large data set of over 80,000 seismic events acquired with a dense seismic network deployed in order to study the yearly rapid drainage of Gornersee lake, a nearby ice-marginal lake. Using simple frequency and distance scaling and Greenâs functions for a homogeneous half-space, we calculated moment tensor solutions for icequakes with M_w-1.5 using a full-waveform inversion method usually applied to moderate seismic events (M_w>4) recorded at local to regional distances (â50â700 km). Inversions from typical shallow events are shown to represent tensile crack openings. This explains well the dominating Rayleigh waves and compressive first motions observed at all recording seismograms. As these characteristics can be observed in most icequake signals, we believe that the vast majority of icequakes recorded in the 2 yr is due to tensile faulting, most likely caused by surface crevasse openings. We also identified a shallow cluster with somewhat atypical waveforms in that they show less dominant Rayleigh waves and quadrantal radiation patterns of first motions. Their moment tensors are dominated by a large double-couple component, which is strong evidence for shear faulting. Although less than a dozen such icequakes have been identified, this is a substantial result as it shows that shear faulting in glacier ice is generally possible even in the absence of extreme flow changes such as during glacier surges. A third source of icequakes was located at 100 m depth. These sources can be represented by tensile crack openings. Because of the high-hydrostatic pressure within the ice at these depths, these events are most likely related to the presence of water lenses that reduce the effective stress to allow for tensile faulting
Evaluation of implementation, compliance and acceptance of partial smoking bans among hospitality workers before and after the Swiss Tobacco Control Act
Background The World Health Organization recommends uniform comprehensive smoking bans in public places. In Switzerland, regulations differ between various areas and are mostly incomplete for hospitality venues. As ambiguous regulations offer more leeway for implementation, we evaluated the Swiss regulations with respect to their effects on implementation, acceptance and compliance among hospitality workers. Methods In our longitudinal study, a standardized, self-administered questionnaire was mailed to a sample of 185 hospitality workers before and 4-6 month after the smoking ban came into effect. The matched longitudinal sample comprised 71 participants (repeated response rate 38.4%). We developed a seven-item acceptance scale. Logistic regressions were performed to explore the factors associated with acceptance. Results Acceptance of smoking bans was influenced by smoking status and perceived annoyance with second-hand smoke in private. Although not statistically significant (P = 0.09), we found some indications that post-ban acceptance increased in an area with strict regulations, whereas it decreased in two areas with less stringent regulations. Conclusions Tobacco bans in Swiss hospitality venues are still in a period of consolidation. The incomplete nature of the law may also have had a negative impact on the development of greater acceptanc
Ion Funnels for the Masses: Experiments and Simulations with a Simplified Ion Funnel
A modified ion funnel is described. Counterintuitively, increased spacing between electrodes results in enhanced âfocusingâ of the ions through the funnel. Consequently, the internal diameter (i.d.) of the funnel need not decrease to the conductance limit (as in previous designs). A simple dc-only lens, which also serves as the conductance limit, combined with the natural flow of gas is used to extract the ions from the funnel. Ions with mass to charge ratios varying between 75 and 3000 m/z are passed through the funnel with no apparent discrimination. The funnel can be operated under mild conditions that preserve weakly bound noncovalent complexes. After testing several designs, a thin closely spaced dc lens was found to be the best solution for extracting ions. A simple method for simulating ion trajectories at nonzero pressures based on ion mobility and explicit diffusion is described. This theoretical approach was used to design and calculate ion trajectories for the modified funnel presented here. Finally, the increased spacing between electrodes in the current funnel significantly relaxes machining constraints, reduces cost, and enhances ease of use versus previous funnel designs
Polyphyly of non-bioluminescent Vibrio fischeri sharing a lux-locus deletion
available in PMC 2013 May 16This study reports the first description and molecular characterization of naturally occurring, non-bioluminescent strains of Vibrio fischeri. These âdarkâV. fischeri strains remained non-bioluminescent even after treatment with both autoinducer and aldehyde, substrate additions that typically maximize light production in dim strains of luminous bacteria. Surprisingly, the entire lux locus (eight genes) was absent in over 97% of these dark V. fischeri strains. Although these strains were all collected from a Massachusetts (USA) estuary in 2007, phylogenetic reconstructions allowed us to reject the hypothesis that these newly described non-bioluminescent strains exhibit monophyly within the V. fischeri clade. These dark strains exhibited a competitive disadvantage against native bioluminescent strains when colonizing the light organ of the model V. fischeri host, the Hawaiian bobtail squid Euprymna scolopes. Significantly, we believe that the data collected in this study may suggest the first observation of a functional, parallel locus-deletion event among independent lineages of a non-pathogenic bacterial species.National Institutes of Health (U.S.) (NIH Molecular Biosciences (5T32GM007215-35))National Institutes of Health (U.S.) (NIH Microbes in Health and Disease, training grant (2T32AI055397-07))Gordon and Betty Moore FoundationBroad Institute of MIT and Harvard (SPARC programme)National Science Foundation (U.S.) (NSF IOS 0841507)National Institutes of Health (U.S.) (NIH R01 RR12294)National Science Foundation (U.S.) (NSF Microbial Systems in the Biosphere programme)Woods Hole Center for Oceans & Human Healt
Leadership Development Programs in College Athletics: An Exploration of the Student-Athlete Experience
Vergleich dreier unterschiedlich spezialisierter Winterweizen-Populationen unter ökologischen und konventionellen Anbaubedingungen in Deutschland und England
Three Composite Cross Populations (CCPs) of winter wheat were created in 2001, one from crossing high baking quality parents (called QCCP), one based on high yielding parents (YCCP), and one created from both parent sets combined (YQ). All three CCPs were grown for several years in the UK and in Germany under conventional and organic cropping management. Based on properties of the different parent sets, yields were predicted to be highest in the YCCP and lowest in the QCCP, with the YQCCP in between. However, data showed that the YCCP was not significantly higher-yielding than the more generalist YQCCP in five out of six sites; in fact, the YQCCP even tended to outyield the YCCP on average over all sites, and this effect was significant at the German conventional site. Our results suggest that high diversity present in generalist populations of wheat may convey yield advantages
Accurate measurement of 5-methylcytosine and 5-hydroxymethylcytosine in human cerebellum DNA by oxidative bisulfite on an array (OxBS-array).
The Infinium 450K Methylation array is an established tool for measuring methylation. However, the bisulfite (BS) reaction commonly used with the 450K array cannot distinguish between 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC). The oxidative-bisulfite assay disambiguates 5mC and 5hmC. We describe the use of oxBS in conjunction with the 450K array (oxBS-array) to analyse 5hmC/5mC in cerebellum DNA. The "methylation" level derived by the BS reaction is the combined level of 5mC and 5hmC at a given base, while the oxBS reaction gives the level of 5mC alone. The level of 5hmC is derived by subtracting the oxBS level from the BS level. Here we present an analysis method that distinguishes genuine positive levels of 5hmC at levels as low as 3%. We performed four replicates of the same sample of cerebellum and found a high level of reproducibility (average r for BS = 98.3, and average r for oxBS = 96.8). In total, 114,734 probes showed a significant positive measurement for 5hmC. The range at which we were able to distinguish 5hmC occupancy was between 3% and 42%. In order to investigate the effects of multiple replicates on 5hmC detection we also simulated fewer replicates and found that decreasing the number of replicates to two reduced the number of positive probes identified by > 50%. We validated our results using qPCR in conjunction with glucosylation of 5hmC sites followed by MspI digestion and we found good concordance with the array estimates (r = 0.94). This experiment provides a map of 5hmC in the cerebellum and a robust dataset for use as a standard in future 5hmC analyses. We also provide a novel method for validating the presence of 5hmC at low levels, and highlight some of the pitfalls associated with measuring 5hmC and 5mC.S. Balasubramanian is a Senior Investigator of The Wellcome Trust and the Balasubramanian group is core-funded by Cancer Research UK. We would like to thank Tobias Ost and Christine Clark of Cambridge Epigenetix Ltd. for valuable discussions and development of the method.This article was originally published in PLOS ONE (Field SF, Beraldi D, Bachman M, Stewart SK, Beck S, Balasubramanian S, PLoS ONE 2015, 10(2): e0118202. doi:10.1371/journal.pone.0118202
High resolution time series reveals cohesive but short-lived communities in coastal plankton
© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 9 (2018): 266, doi:10.1038/s41467-017-02571-4.Because microbial plankton in the ocean comprise diverse bacteria, algae, and protists that are subject to environmental forcing on multiple spatial and temporal scales, a fundamental open question is to what extent these organisms form ecologically cohesive communities. Here we show that although all taxa undergo large, near daily fluctuations in abundance, microbial plankton are organized into clearly defined communities whose turnover is rapid and sharp. We analyze a time series of 93 consecutive days of coastal plankton using a technique that allows inference of communities as modular units of interacting taxa by determining positive and negative correlations at different temporal frequencies. This approach shows both coordinated population expansions that demarcate community boundaries and high frequency of positive and negative associations among populations within communities. Our analysis thus highlights that the environmental variability of the coastal ocean is mirrored in sharp transitions of defined but ephemeral communities of organisms.This work was supported by grants from the U.S. National Science Foundation (OCE-1441943) to M.F.P. and the U.S. Department of Energy (DE-SC0008743) to M.F.P. and E.J.A. A.M.M.-P. was partially supported by the Ramon Areces foundation through a postdoctoral fellowship. D.J.M. was supported by the U.S. National Science Foundation (OCE-1314642) and National Institute of Environmental Health Sciences (1P01ES021923-01) through the Woods Hole Center for Oceans and Human Health
Equivariant Data Augmentation for Generalization in Offline Reinforcement Learning
We present a novel approach to address the challenge of generalization in
offline reinforcement learning (RL), where the agent learns from a fixed
dataset without any additional interaction with the environment. Specifically,
we aim to improve the agent's ability to generalize to out-of-distribution
goals. To achieve this, we propose to learn a dynamics model and check if it is
equivariant with respect to a fixed type of transformation, namely translations
in the state space. We then use an entropy regularizer to increase the
equivariant set and augment the dataset with the resulting transformed samples.
Finally, we learn a new policy offline based on the augmented dataset, with an
off-the-shelf offline RL algorithm. Our experimental results demonstrate that
our approach can greatly improve the test performance of the policy on the
considered environments
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