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The radiative characteristics and lifetimes of contrails are dependent on the number concentration of ice-forming particles in the engine exhaust plume. Aircraft gas turbine engines produce a variety of particles, yet it is understood that non-volatile black carbon aggregates are the dominant source of ice-forming particles with typical, fossil-derived jet fuel. However, with cleaner combustion technologies and the adoption of alternative fuels (e.g. hydrogen or synthetic aviation fuel), non-volatile black carbon particle emissions are expected to decrease or even be eliminated. Under these conditions, contrail properties will depend upon the concentration and characteristics of particles other than black carbon. Ultrafine (< 100 nm) jet lubrication oil droplets constitute a significant fraction of the total organic particulate matter released by aircraft; however, their ability to form contrail ice crystals has hitherto been unexplored. In this work, we experimentally investigate the activation and freezing behaviour of lubrication oil droplets using an expansion chamber, assessing their potential as ice-forming particles. We generate lubrication oil droplets with a geometric mean mobility diameter of (100.9 ± 0.6) nm and show that these activate to form water droplets, which subsequently freeze when the temperature is below ∼ 235 K. We find that nucleation on lubrication oil droplets should be considered in future computational studies – particularly under soot-poor conditions – and that these studies would benefit from particle size distribution measurements at cruise altitude. Overall, taking steps to reduce lubrication oil number emissions would help reduce the climate impact of contrail cirrus.

This review paper describes the energy-upgraded Continuous Electron Beam Accelerator Facility (CEBAF) accelerator. This superconducting linac has achieved 12 GeV beam energy by adding 11 new high-performance cryomodules containing 88 superconducting cavities that have operated cw at an average accelerating gradient of 20 MV/m. After reviewing the attributes and performance of the previous 6 GeV CEBAF accelerator, we discuss the upgraded CEBAF accelerator system in detail with particular attention paid to the new beam acceleration systems. In addition to doubling the acceleration in each linac, the upgrade included improving the beam recirculation magnets, adding more helium cooling capacity to allow the newly installed modules to run cold, adding a new experimental hall, and improving numerous other accelerator components. We review several of the techniques deployed to operate and analyze the accelerator performance and document system operating experience and performance. In the final portion of the document, we present much of the current planning regarding projects to improve accelerator performance and enhance operating margins, and our plans for ensuring CEBAF operates reliably into the future. For the benefit of potential users of CEBAF, the performance and quality measures for the beam delivered to each of the experimental halls are summarized in the Appendix.

Despite safe methods of weight management being reported, adverse rapid weight loss (RWL) practices persist in horseracing. The aims of this study were to understand the factors that influence persistent RWL to ultimately develop potential solutions to ameliorate the associated issues. Semi-structured interviews were conducted with 33 participants representing relevant sectors of the Irish horseracing industry (jockeys n = 15; trainers/owners/breeders n = 7; health professionals n = 6; racing officials n = 5). Three higher order themes, each containing sub-themes were generated via reflexive thematic analysis: 1) Industry acceptance of RWL/wasting (broad awareness of the severity of RWL, RWL/wasting is part of the job, traditionalist attitude to jockey athletic identity) 2) Change is needed but will face barriers (alter minimum weight & claims, individualise minimum riding weights, implement mandatory education and supports for jockeys), and 3) Change requires a multifaceted, strategic approach (provide scientific rationale for change, industry wide approach is required). This study provides a comprehensive framework for understanding the factors influencing persistent RWL and provides potential changes to limit RWL. Implementing a multifaceted solution adapted to the context of horseracing is recommended, while industry agreement and endorsement of change by role models may facilitate change. Developing an evidence-based rationale should be priority to reduce RWL.

University study is a period of psychological vulnerability for many individuals. International college students may be particularly vulnerable to experiencing distress and developing a mental illness due to challenges of relocation and acculturation. The aim of this meta-analytic review was to synthesize the literature on the mental health correlates and outcomes of domestic and international tertiary students. A total of 35 studies were identified via search PsycINFO, PubMed, CINAHL, and Scopus databases. Results showed that, among 283,412 participants, very small but non-significant effects were found between domestic and international students on anxiety: r = 0.04; depression: r = -0.01; psychological distress: r = -0.01; and wellbeing: r = -0.01. Most studies were of relatively poor quality. Among high-quality studies, international students reported fewer symptoms of anxiety, depression, and stress than domestic students. On the other hand, domestic students declared higher wellbeing scores on quality-of-life measures. Despite these mixed findings, many students in the included studies reported poor mental health and wellbeing. Further research examining the mental health and wellbeing of domestic and international students is needed, with particular attention to the underlying needs and stressors that affect each subgroup to develop effective supports and countermeasures.

Abstract Background Past research on the association between insomnia and suicidal ideation (SI) has produced mixed findings. The current study explored the relationship between insomnia, SI, and past-year mental health status among a large Canadian Forces (CF) sample. Method Data was obtained from the 2013 Canadian Forces Mental Health Survey (CFMHS), and included a large representative sample of Canadian Regular Forces personnel (N = 6700). A series of univariate logistic regressions were conducted to test individual associations between past-year mental health status, insomnia, and potential confounds and SI. Mental health status included three groups: 0, 1, or two or more probable diagnoses of posttraumatic stress disorder (PTSD), major depressive disorder (MDD), generalized anxiety disorder (GAD), panic disorder (PD) and alcohol abuse/dependence. Stepwise multivariate logistic regression was used to assess the relationship between insomnia and SI with mental health status as a moderator. Results 40.8% of respondents reported experiencing insomnia. Both insomnia and number of mental health conditions incrementally increased the risk of SI. However, past-year mental health status was a significant moderator of this relationship, such that for CF personnel with either no (AOR = 1.61, 1.37–1.89) or only one past-year mental health condition (AOR = 1.39, 1.12–1.73), an incremental increase in insomnia was associated with an increased likelihood of SI. However, in personnel with two or more past-year mental health disorders, insomnia was no longer significantly associated with SI (AOR = 1.04, 0.81–1.33). Conclusions Insomnia significantly increased the odds of SI, but only among individuals with no or one mental health condition. Findings highlight the importance of assessing insomnia among CF members in order to further suicide prevention efforts.

Background: Antonovsky’s concept of sense of coherence (SOC) – as a global orientation reflecting an individual’s feeling of confidence in both the predictability of their internal and external environment and their ability to cope with stressful and challenging situations in life – shows a negative association with symptoms of post-traumatic stress. However, single studies varying in study characteristics provide heterogeneous effect size estimations. Objective: The purpose of the current study is to investigate the relationship between SOC and post-traumatic stress disorder (PTSD) symptom severity for the first time on a meta-analytical level. Method: The random-effects meta-analysis is based on zero-order correlations (r) and consists of 47 independent samples out of 45 studies (N = 10,883). Results: After correcting for sampling error, the mean correlation between SOC and PTSD symptoms was M(r) = −.41 (excluding four outliers: −.39). However, this effect could not be generalized to all types of PTSD samples owing to substantial remaining heterogeneity. Subsequent moderator analyses investigating the influence of different SOC and PTSD measures, trauma type and duration, mean age and gender imbalances per sample did not reveal significant moderating effects. Conclusions: The meta-analysis reveals a substantial correlation between SOC and PTSD symptom severity: higher SOC levels are associated with lower symptom severity. Thus, future research should progress to the question of whether the relationship between SOC and post-traumatic stress is causal, and by which factors it is moderated. Abbreviations: CD, Cook’s distance; DSM, Diagnostic and Statistical Manual of Mental Disorders; (G)RR, general (and specific) resistance resources; IES(-R), Impact of Event Scale (Revised); PDS, Posttraumatic Stress Diagnostic Scale; PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses; PTSD, post-traumatic stress disorder; SDR, standard deleted residual; SOC, sense of coherence; SOC-R, Sense of Coherence Scale – Revised

In the southeastern US, substantial emissions of isoprene from deciduous trees undergo atmospheric oxidation to form secondary organic aerosol (SOA) that contributes to fine particulate matter (PM2.5). Laboratory studies have revealed that anthropogenic pollutants, such as sulfur dioxide (SO2), oxides of nitrogen (NOx), and aerosol acidity, can enhance SOA formation from the hydroxyl radical (OH)-initiated oxidation of isoprene; however, the mechanisms by which specific pollutants enhance isoprene SOA in ambient PM2.5 remain unclear. As one aspect of an investigation to examine how anthropogenic pollutants influence isoprene-derived SOA formation, high-volume PM2.5 filter samples were collected at the Birmingham, Alabama (BHM), ground site during the 2013 Southern Oxidant and Aerosol Study (SOAS). Sample extracts were analyzed by gas chromatography–electron ionization-mass spectrometry (GC/EI-MS) with prior trimethylsilylation and ultra performance liquid chromatography coupled to electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-QTOFMS) to identify known isoprene SOA tracers. Tracers quantified using both surrogate and authentic standards were compared with collocated gas- and particle-phase data as well as meteorological data provided by the Southeastern Aerosol Research and Characterization (SEARCH) network to assess the impact of anthropogenic pollution on isoprene-derived SOA formation. Results of this study reveal that isoprene-derived SOA tracers contribute a substantial mass fraction of organic matter (OM) ( ∼ 7 to ∼ 20 %). Isoprene-derived SOA tracers correlated with sulfate (SO42−) (r2 = 0.34, n = 117) but not with NOx. Moderate correlations between methacrylic acid epoxide and hydroxymethyl-methyl-α-lactone (together abbreviated MAE/HMML)-derived SOA tracers with nitrate radical production (P[NO3]) (r2 = 0.57, n = 40) were observed during nighttime, suggesting a potential role of the NO3 radical in forming this SOA type. However, the nighttime correlation of these tracers with nitrogen dioxide (NO2) (r2 = 0.26, n = 40) was weaker. Ozone (O3) correlated strongly with MAE/HMML-derived tracers (r2 = 0.72, n = 30) and moderately with 2-methyltetrols (r2 = 0.34, n = 15) during daytime only, suggesting that a fraction of SOA formation could occur from isoprene ozonolysis in urban areas. No correlation was observed between aerosol pH and isoprene-derived SOA. Lack of correlation between aerosol acidity and isoprene-derived SOA is consistent with the observation that acidity is not a limiting factor for isoprene SOA formation at the BHM site as aerosols were acidic enough to promote multiphase chemistry of isoprene-derived epoxides throughout the duration of the study. All in all, these results confirm previous studies suggesting that anthropogenic pollutants enhance isoprene-derived SOA formation.

Sixteen temperature minimum and maximum series are used to quantify annual and seasonal changes in temperature means and extremes over Georgia (Southern Caucasus) during the period 1961 and 2010. Along with trends in mean minimum and maximum temperature, eight indices are selected from the list of climate extreme indices as defined by the Expert Team on Climate Change Detection and Indices (ETCCDI) of the Commission for Climatology of the World Meteorological Organization (WMO), for studying trends in temperature extremes. Between the analysis periods 1961–2010, 1971–2010 and 1981–2010 pronounced warming trends are determined for all Georgia-averaged trends in temperature means and extremes, while all magnitudes of trends increase towards the most recent period. During 1981 and 2010, significant warming trends for annual minimum and maximum temperature at a rate of 0.39 °C (0.47 °C) days/decade and particularly for the warm temperature extremes, summer days, warm days and nights and the warm spell duration index are evident, whereas warm extremes show larger trends than cold extremes. The most pronounced trends are determined for summer days 6.2 days/decade, while the warm spell duration index indicates an increase in the occurrence of warm spells by 5.4 days/decade during 1981 and 2010. In the comparison of seasonal changes in temperature means and extremes, the largest magnitudes of warming trends can be observed for temperature maximum in summer and temperature minimum in fall. Between 1981 and 2010, summer maximum temperature shows a significant warming at a rate of 0.84 °C/decade, increasing almost twice as fast as its annual trend (0.47 °C/decade). The Georgia-averaged trends for temperature minimum in fall increase by 0.59 °C/decade. Strongest significant trends in temperature extremes are identified during 1981 and 2010 for warm nights (4.6 days/decade) in summer and fall as well as for warm days (5.6 days/decade) in summer. Analyses demonstrate that there have been increasing warming trends since the 1960s, particularly for warm extremes during summer and fall season, accompanied by a constant warming of temperature means in Georgia.

We assess the potential of the water-soluble fraction of atmospheric fine aerosols in the southeastern United States to generate reactive oxygen species (ROS) and identify major ROS-associated emission sources. ROS-generation potential of particles was quantified by the dithiothreitol (DTT) assay and involved analysis of fine particulate matter (PM) extracted from high-volume quartz filters (23 h integrated samples) collected at various sites in different environmental settings in the southeast, including three urban-Atlanta sites, in addition to a rural site. Paired sampling was conducted with one fixed site in Atlanta (Jefferson Street), representative of the urban environment, with the others rotating among different sites, for ~250 days between June 2012 and September 2013 (N=483). A simple linear regression between the DTT activity and aerosol chemical components revealed strong associations between PM ROS-generation potential and secondary organic aerosol (WSOC – water-soluble organic carbon) in summer, and biomass burning markers in winter. Redox-active metals were also somewhat correlated with the DTT activity, but mostly at urban and roadside sites. Positive matrix factorization (PMF) was applied to apportion the relative contribution of various sources to the ROS-generation potential of water-soluble PM2.5 in urban Atlanta. PMF showed that vehicular emissions contribute uniformly throughout the year (12–25%), while secondary oxidation processes dominated the DTT activity in summer (46%) and biomass burning in winter (47%). Road dust was significant only during drier periods (~12% in summer and fall). Source apportionment by chemical mass balance (CMB) was reasonably consistent with PMF, but with higher contribution from vehicular emissions (32%). Given the spatially large data set of PM sampled over an extended period, the study reconciles the results from previous work that showed only region- or season-specific aerosol components or sources contributing to PM ROS activity, possibly due to smaller sample sizes. The ubiquitous nature of the major sources of PM-associated ROS suggests widespread population exposures to aerosol components that have the ability to catalyze the production of oxidants in vivo.

Annual changes to climate extreme indices in Georgia (Southern Caucasus) from 1971 to 2010 are studied using homogenized daily minimum and maximum temperature and precipitation series. Fourteen extreme temperature and 11 extreme precipitation indices are selected from the list of core climate extreme indices recommended by the World Meteorological Organization – Commission for Climatology (WMO-CCL) and the research project on Climate Variability and Predictability (CLIVAR) of the World Climate Research Programme (WCRP). Trends in the extreme indices are studied for 10 minimum and 11 maximum temperature and 24 precipitation series for the period 1971–2010. Between 1971 and 2010 most of the temperature extremes show significant warming trends. In 2010 there are 13.3 fewer frost days than in 1971. Within the same time frame there are 13.6 more summer days and 7.0 more tropical nights. A large number of stations show significant warming trends for monthly minimum and maximum temperature as well as for cold and warm days and nights throughout the study area, whereas warm extremes and night-time based temperature indices show greater trends than cold extremes and daytime indices. Additionally, the warm spell duration indicator indicates a significant increase in the frequency of warm spells between 1971 and 2010. Cold spells show an insignificant increase with low spatial coherence. Maximum 1-day and 5-day precipitation, the number of very heavy precipitation days, very wet and extremely wet days as well as the simple daily intensity index all show an increase in Georgia, although all trends manifest a low spatial coherence. The contribution of very heavy and extremely heavy precipitation to total precipitation increased between 1971 and 2010, whereas the number of wet days decreases.

Aims: The use of biodegradable-polymer drug-eluting stents has been shown to provide favorable results when compared with durable polymer drug-eluting stents and long-term follow up data have recently shown significant reductions in terms of very late stent thrombosis. Aim of the present study was to assess the safety and efficacy profile of a novel biodegradable polymer DES, the Yukon Choice Flex sirolimus-eluting stent. Methods: We report here the one-year clinical outcomes associated with the use of the Yukon Choice Flex sirolimus-eluting stent in an all-comers patient population. The present stent represents a further refinement of the stent platform tested in the ISAR TEST 3 and 4 randomized clinical trials. A total of 778 consecutive patients undergoing implantation of this stent were enrolled in the present observational study and prospectively followed for one year. Results: The use of the Yukon Choice Flex stent in a patient population with complex coronary lesion morphology was associated with optimal immediate angiographic results. At one year follow up the rates of death, myocardial infarction, definite stent thrombosis and ischemia-driven target lesion revascularization were respectively 2.4%, 1.9%, 0.3% and 11.3%. Conclusions: The use of the sirolimus-eluting biodegradable polymer Yukon Choice Flex stent in an all-comers population of patients with complex coronary artery disease is associated with a favorable safety and efficacy profile up to one year follow up.

Background: Health coaching sessions that incorporate goal setting may help improve college students' health behaviors. Purpose: This study examined whether specific goal-setting practices moderated changes in health behaviors during an online wellness intervention in college students. Methods: Participants were 90 college students recruited from one US university. The intervention was a one-hour virtual one-on-one health coaching session where participants set two goals for either physical activity (Metabolic Equivalent Task (MET)-minutes or MET-minutes), nutrition, sleep, or stress management. Self-reported baseline behaviors were collected, and follow-up surveys were completed at 6- and 12-weeks. Mixed effects models examined behavior change outcomes across the follow-up timepoints while testing the moderating effect of goal setting using interactions. Results: The Goal×Time interaction was significant for moderate MET-minutes at 1st follow-up (b = 443, p = 0.003), and for total MET-minutes at the 2nd follow-up (b = 717, p = 0.047). The Goal×Time interaction was also significant for stress management at 1st follow-up (Odds Ratio = 7.3, p = 0.042). Discussion: Participants who set physical activity and stress management goals had significantly higher physical activity and utilized more stress management techniques. Translation to Health Education Practice: The use of specific goal-setting strategies for physical activity and stress management is recommended during online health coaching sessions. A AJHE Self-Study quiz is online for this article via the SHAPE America Online Institute (SAOI) http://portal.shapeamerica.org/trn-Webinars.

Background: Important tools in preventing the spread of COVID-19 include contract tracing and adherence to isolation guidelines after a positive diagnosis of COVID-19. This is especially relevant among college students who are often away from support systems at home, living in high-density housing, and may not experience serious symptoms from COVID-19 while still contagious. Objective: As text message-based interventions have been found effective in addressing health behaviors among young adults, we conducted formative research to explore how text messaging could support students in adhering to isolation guidelines. Participants: A convenience sample of college students (n = 104) at one university. Methods: An online survey gathered students' perceptions of helpful components to include in a text message-based intervention. Results: Students expressed interest in receiving text messages with support, encouragement, and resources during their time in isolation following a COVID-19 diagnosis. Conclusions: Based on the results, we developed a text message-based intervention designed to provide motivation, support, distraction, and information on resources.

Light absorbing organic carbon, often called brown carbon, has the potential to significantly contribute to the visible light-absorption budget, particularly at shorter wavelengths. Currently, the relative contributions of particulate brown carbon to light absorption, as well as the sources of brown carbon, are poorly understood. With this in mind size-resolved direct measurements of brown carbon were made at both urban (Atlanta), and rural (Yorkville) sites in Georgia. Measurements in Atlanta were made at both a representative urban site and a road-side site adjacent to a main highway. Fine particle absorption was measured with a multi-angle absorption photometer (MAAP) and seven-wavelength Aethalometer, and brown carbon absorption was estimated based on Mie calculations using direct size-resolved measurements of chromophores in solvents. Size-resolved samples were collected using a cascade impactor and analyzed for water-soluble organic carbon (WSOC), organic and elemental carbon (OC and EC), and solution light-absorption spectra of water and methanol extracts. Methanol extracts were more light-absorbing than water extracts for all size ranges and wavelengths. Absorption refractive indices of the organic extracts were calculated from solution measurements for a range of wavelengths and used with Mie theory to predict the light absorption by fine particles comprised of these components, under the assumption that brown carbon and other aerosol components were externally mixed. For all three sites, chromophores were predominately in the accumulation mode with an aerodynamic mean diameter of 0.5 μm, an optically effective size range resulting in predicted particle light absorption being a factor of 2 higher than bulk solution absorption. Mie-predicted brown carbon absorption at 350 nm contributed a significant fraction (20 to 40%) relative to total light absorption, with the highest contributions at the rural site where organic to elemental carbon ratios were highest. Brown carbon absorption, however, was highest by the roadside site due to vehicle emissions. The direct size-resolved measurement of brown carbon in solution definitively shows that it is present and optically important in the near-UV range in both a rural and urban environment during the summer when biomass burning emissions are low. These results allow estimates of brown carbon aerosol absorption from direct measurements of chromophores in aerosol extracts.

We examined the prevalence and correlates of anticipated responses to hypothetical cigar price increases. Data are from a 2021 representative sample of U.S. adults who reported past-30-day cigar use (n = 454; mean age = 39.8 years). Weighted multivariable logistic regressions assessed the correlates of behavior change responses. If cigar price increased, 77.2% intend to pay more, 44.7% intend to reduce use, and 39.9%, 37.7%, and 17.1% intend to use other tobacco, cannabis, and cheaper cigars, respectively. Those who smoked cigarillos (vs. other cigars) had higher odds of intending to pay more (adjusted odds ratio [AOR] = 2.73; 95% confidence interval [CI] = [1.41, 5.29]) and use other tobacco (AOR = 2.35; 95%CI = [1.26, 4.36]). Those who smoked within 5 min of waking (vs. > 60 min) had higher odds of intending to use cheaper cigars (AOR = 5.19, 95%CI = [1.38, 19.46]). Almost half of U.S. adults who report past-30-day cigar use may reduce cigar smoking in response to price increases, though behavioral response may depend on cigar type smoked and tobacco dependence.