276 research outputs found

    Input-output theory for fermions in an atom cavity

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    We generalize the quantum optical input-output theory developed for optical cavities to ultracold fermionic atoms confined in a trapping potential, which forms an "atom cavity". In order to account for the Pauli exclusion principle, quantum Langevin equations for all cavity modes are derived. The dissipative part of these multi-mode Langevin equations includes a coupling between cavity modes. We also derive a set of boundary conditions for the Fermi field that relate the output fields to the input fields and the field radiated by the cavity. Starting from a constant uniform current of fermions incident on one side of the cavity, we use the boundary conditions to calculate the occupation numbers and current density for the fermions that are reflected and transmitted by the cavity

    Pilot Implementation of a Wellness and Tobacco Cessation Curriculum in North Carolina Group Homes

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    (2) Instructors used prior professional experiences and goal setting to facilitate program success and participant engagementDespite a steady decline in smoking rates in recent decades, individuals with mental illness continue to smoke at disproportionately higher rates than the general population. Adults with mental illness are motivated to quit and quit with rates similar to the general population when evidence-based cessation interventions are used. To build an evidence base for a wellness and cessation curriculum aimed at individuals with mental illness, the Breathe Easy Live Well (BELW) program was pilot tested in two group homes in North Carolina in the spring of 2014. Evaluators conducted pre- and post-implementation site visits and interviews with program instructors to assess outcomes as well as barriers and facilitators to implementation. Qualitative analysis of the data indicated that implementation was successful in both group homes, and the following themes emerged: (1) Training and technical assistance provided throughout implementation was sufficient; (3) Fostering positive coping strategies contributed to reports of reduced smoking; (4) Curriculum length may be a barrier to recruitment. Additional results included an increased interest among group home residents in more diligently managing mental illness symptoms and one group home moving the designated smoking area out of the direct path of the entrance/exit. Results of this pilot project suggest that BELW could be a potentially useful tool for group home staff to address health and wellness along with smoking cessation among individuals with mental illness

    The tobacco 21 movement and electronic nicotine delivery system use among youth

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    Cigarette smoking prevalence in the United States has significantly decreased over the past few decades to 15.1% among adults 1 and 9.3% among high school students. Declines are a result of a variety of tobacco control initiatives, including limits on tobacco marketing, higher per-unit cost of tobacco products, clean air legislation, mass media campaigns, and reductions in youth access. At the same time, use of electronic nicotine delivery systems (ENDS) has rapidly increased. The role of ENDS in reducing or exacerbating population-level morbidity and mortality from tobacco products remains hotly contested. The increased use of ENDS, and the fact that smoking remains the leading cause of preventable death in the United States indicate that additional policy interventions are needed to work toward the tobacco “endgame.” One such intervention is raising the minimum legal sales age (MLSA) to 21 years. As more states and localities enact Tobacco 21 laws, it is important to consider how such policies, initially designed to decrease combustible cigarette and other tobacco use, will interact with ENDS use patterns among youth

    Impact of non-menthol flavours in e-cigarettes on perceptions and use: an updated systematic review

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    Objectives Given the exponential increase in the use of e-cigarettes among younger age groups and in the growth in research on e-cigarette flavours, we conducted a systematic review examining the impact of non-menthol flavoured e-cigarettes on e-cigarette perceptions and use among youth and adults. Design PubMed, Embase, PyscINFO and CINAHL were systematically searched for studies published and indexed through March 2018. Eligibility criteria Quantitative observational and experimental studies that assessed the effect of non-menthol flavours in e-cigarettes on perceptions and use behaviours were included. Specific outcome measures assessed are appeal, reasons for use, risk perceptions, susceptibility, intention to try, initiation, preference, current use, quit intentions and cessation. Data extraction and synthesis Three authors independently extracted data related to the impact of flavours in tobacco products. Data from a previous review were then combined with those from the updated review for final analysis. Results were then grouped and analysed by outcome measure. Results The review included 51 articles for synthesis, including 17 published up to 2016 and an additional 34 published between 2016 and 2018. Results indicate that non-menthol flavours in e-cigarettes decrease harm perceptions (five studies) and increase willingness to try and initiation of e-cigarettes (six studies). Among adults, e-cigarette flavours increase product appeal (seven studies) and are a primary reason many adults use the product (five studies). The role of flavoured e-cigarettes on smoking cessation remains unclear (six studies). Conclusion This review provides summary data on the role of non-menthol flavours in e-cigarette perceptions and use. Consistent evidence shows that flavours attract both youth and adults to use e-cigarettes. Given the clear findings that such flavours increase product appeal, willingness to try and initiation among youth, banning non-menthol flavours in e-cigarettes may reduce youth e-cigarette use. Longitudinal research is needed to examine any role flavours may play in quit behaviours among adults

    Hydrodynamic theory for granular gases

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    A granular gas subjected to a permanent injection of energy is described by means of hydrodynamic equations derived from a moment expansion method. The method uses as reference function not a Maxwellian distribution fMf_{\sf M} but a distribution f0=ΦfMf_0 = \Phi f_{\sf M}, such that Φ\Phi adds a fourth cumulant κ\kappa to the velocity distribution. The formalism is applied to a stationary conductive case showing that the theory fits extraordinarily well the results coming from our molecular dynamic simulations once we determine κ\kappa as a function of the inelasticity of the particle-particle collisions. The shape of κ\kappa is independent of the size NN of the system.Comment: 10 pages, 9 figures, more about our research in http://www.cec.uchile.cl/cinetica

    Factors Influencing Trust in Agencies That Disseminate Tobacco Prevention Information

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    Several health-related agencies administer national and targeted public education campaigns to provide health information and change health-related behaviors. The trust the public has in these agencies as the source of the message impacts the effectiveness of their communication campaigns. In this study, we explore the perceived trust of agencies that communicate health messages in the tobacco control field. As part of a larger tobacco regulatory science study, we conducted six 90-min focus groups comprising 41 participants. Five main themes emerged pertinent to the agency: (1) its integrity, (2) its competence, (3) its motives, (4) how it is portrayed in the media, and (5) skepticism and mistrust about it. Given the significant resources spent on health messaging to the public and potential benefits offered by this communication, an understanding of public trust in the agencies as the source of health messages is important. Findings suggest health information may be ignored or discounted when there is mistrust in the agency sending those messages

    Youth source of acquisition for E-Cigarettes

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    As rates of traditional cigarette smoking have decreased among youth over the past several years, rates of e-cigarette use have increased. Little evidence exists on how youth obtain e-cigarettes. We used data from middle and high school students under the age of 18 who reported using an e-cigarette in the past 30 days from the 2017 North Carolina Youth Tobacco Survey (n = 640). We used chi-square tests and multivariable logistic regressions to examine correlates of access and place of acquisition. Over half (51.5%) of youth report acquiring e-cigarettes from a friend. Youth in 12th grade had higher odds of acquiring e-cigarettes from a vape shop (aOR: 2.54, 95% CI: 1.25, 5.15) or retail outlet (aOR: 2.40, 95% CI: 1.18, 4.90) than youth in middle school. Compared to non-Hispanic white youth, Hispanic youth had lower odds of acquiring e-cigarettes from a vape shop (aOR: 0.42, 95% CI: 0.20, 0.87). Youth living with someone who uses e-cigarettes, compared to those who did not, had higher odds of acquiring e-cigarettes from a family member (aOR: 3.95, 95% CI: 1.94, 8.05). Finally, current smokers had higher odds of acquiring e-cigarettes from a retail outlet (aOR: 3.28, 95% CI: 1.88, 5.70) and lower odds of acquiring e-cigarettes from a friend (aOR: 0.53, 95% CI: 0.36, 0.77). Youth primarily reported obtaining e-cigarettes from a friend. Living with someone who uses e-cigarettes may be a risk factor for acquiring e-cigarettes from family members. Identifying sources of e-cigarette acquisition will help inform interventions preventing youth e-cigarette access

    Structural Probe of a Glass Forming Liquid: Generalized Compressibility

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    We introduce a new quantity to probe the glass transition. This quantity is a linear generalized compressibility which depends solely on the positions of the particles. We have performed a molecular dynamics simulation on a glass forming liquid consisting of a two component mixture of soft spheres in three dimensions. As the temperature is lowered (or as the density is increased), the generalized compressibility drops sharply at the glass transition, with the drop becoming more and more abrupt as the measurement time increases. At our longest measurement times, the drop occurs approximately at the mode coupling temperature TCT_C. The drop in the linear generalized compressibility occurs at the same temperature as the peak in the specific heat. By examining the inherent structure energy as a function of temperature, we find that our results are consistent with the kinetic view of the glass transition in which the system falls out of equilibrium. We find no size dependence and no evidence for a second order phase transition though this does not exclude the possibility of a phase transition below the observed glass transition temperature. We discuss the relation between the linear generalized compressibility and the ordinary isothermal compressibility as well as the static structure factor.Comment: 18 pages, Latex, 26 encapsulated postscript figures, revised paper is shorter, to appear in Phys. Rev.

    Boson-fermion unification, superstrings, and Bohmian mechanics

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    Bosonic and fermionic particle currents can be introduced in a more unified way, with the cost of introducing a preferred spacetime foliation. Such a unified treatment of bosons and fermions naturally emerges from an analogous superstring current, showing that the preferred spacetime foliation appears only at the level of effective field theory, not at the fundamental superstring level. The existence of the preferred spacetime foliation allows an objective definition of particles associated with quantum field theory in curved spacetime. Such an objective definition of particles makes the Bohmian interpretation of particle quantum mechanics more appealing. The superstring current allows a consistent Bohmian interpretation of superstrings themselves, including a Bohmian description of string creation and destruction in terms of string splitting. The Bohmian equations of motion and the corresponding probabilistic predictions are fully relativistic covariant and do not depend on the preferred foliation.Comment: 30 pages, 1 figure, revised, to appear in Found. Phy

    Organic nitrate aerosol formation via NO³ + biogenic volatile organic compounds in the southeastern United States

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    Gas- and aerosol-phase measurements of oxidants, biogenic volatile organic compounds (BVOCs) and organic nitrates made during the Southern Oxidant and Aerosol Study (SOAS campaign, Summer 2013) in central Alabama show that a nitrate radical (NO₃) reaction with monoterpenes leads to significant secondary aerosol formation. Cumulative losses of NO₃ to terpenes are correlated with increase in gasand aerosol-organic nitrate concentrations made during the campaign. Correlation of NO₃ radical consumption to organic nitrate aerosol formation as measured by aerosol mass spectrometry and thermal dissociation laser-induced fluorescence suggests a molar yield of aerosol-phase monoterpene nitrates of 23–44 %. Compounds observed via chemical ionization mass spectrometry (CIMS) are correlated to predicted nitrate loss to BVOCs and show C₁₀H₁₇NO₅, likely a hydroperoxy nitrate, is a major nitrate-oxidized terpene product being incorporated into aerosols. The comparable isoprene product C₅H₉NO₅ was observed to contribute less than 1% of the total organic nitrate in the aerosol phase and correlations show that it is principally a gas-phase product from nitrate oxidation of isoprene. Organic nitrates comprise between 30 and 45% of the NOy budget during SOAS. Inorganic nitrates were also monitored and showed that during incidents of increased coarse-mode mineral dust, HNO₃ uptake produced nitrate aerosol mass loading at a rate comparable to that of organic nitrate produced via NO₃ CBVOCs
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