Latino and Black smokers in the Health and Retirement Study are more likely to quit: the role of light smoking

Abstract Background Older persons are more vulnerable to tobacco mortality and less likely to make quit attempts. Less is known, however, about the role of race and ethnicity on quit rates in the U.S. Using a nationally representative data source of older adults in U.S., we aimed to study racial and ethnic differences in smoking cessation rates. Methods We used data from all waves of the Health and Retirement Study (HRS) between 1992-2012. The HRS is a longitudinal nationally representative survey of adults over the age of 50 in the United States. We followed current smokers at baseline (year 1992) until time to first quit. Race/ethnicity was the main predictor; gender, age, education, marital status, count of chronic medical conditions, depressive symptoms, and drinking at baseline were control variables. Cox regression was used for analysis of time to quit. Results Hazard ratios of quitting during the first ten (Hazard ratio = 1.51, p < 0.05) and 20 years (Hazard ratio = 1.46, p < 0.05) were larger for Latinos over the age of 50 compared to Whites. In addition, hazard ratios of quitting during the first 20 years (Hazard ratio = 1.19, p < 0.05) were larger for Blacks over the age of 50 compared to Whites. These findings were partially explained by cigarette consumption intensity, such that Latinos were lighter smokers and therefore more likely to quit than Whites. Conclusion Latinos and Blacks were more likely than Whites to quit smoking cigarettes within 20 years. However, this finding may be explained by cigarette consumption intensity.http://deepblue.lib.umich.edu/bitstream/2027.42/134608/1/12971_2016_Article_90.pd

The Density Spike in Cosmic-Ray-Modified Shocks: Formation, Evolution, and Instability

We examine the formation and evolution of the density enhancement (density spike) that appears downstream of strong, cosmic-ray-modified shocks. This feature results from temporary overcompression of the flow by the combined cosmic-ray shock precursor/gas subshock. Formation of the density spike is expected whenever shock modification by cosmic-ray pressure increases strongly. That occurence may be anticipated for newly generated strong shocks or for cosmic-ray-modified shocks encountering a region of higher external density, for example. The predicted mass density within the spike increases with the shock Mach number and with shocks more dominated by cosmic-ray pressure. We find this spike to be linearly unstable under a modified Rayleigh-Taylor instability criterion at the early stage of its formation. We confirm this instability numerically using two independent codes based on the two-fluid model for cosmic-ray transport. These two-dimensional simulations show that the instability grows impulsively at early stages and then slows down as the gradients of total pressure and gas density decrease. Observational discovery of this unstable density spike behind shocks, possibly through radio emission enhanced by the amplified magnetic fields would provide evidence for the existence of strongly cosmic-ray modified shock structures.Comment: 26 pages in Latex and 6 figures. Accepted to Ap

Trapped Protostellar Winds and their Breakout

Observations show that high-velocity jets stem from deeply embedded young stars, which may still be experiencing infall from their parent cloud cores. Yet theory predicts that, early in this buildup, any outgoing wind is trapped by incoming material of low angular momentum. As collapse continues and brings in more rapidly rotating gas, the wind can eventually break out. Here we model this transition by following the motion of the shocked shell created by impact of the wind and a rotating, collapsing envelope. We first demonstrate, both analytically and numerically, that our previous, quasi-static solutions are dynamically unstable. Our present, fully time-dependent calculations include cases both where the wind is driven back by infall to the stellar surface, and where it erupts as a true outflow. For the latter, we find that the time of breakout is sim 50,000 yr for wind speeds of 200 km/s. The reason for the delay is that the shocked material, including the swept-up infall, must be able to climb out of the star's gravitational potential well. We explore the critical wind speed necessary for breakout as a function of the mass transport rates in the wind and infall, as well as the cloud rotation rate Omega0 and time since the start of infall. Breakout does occur for realistic parameter choices. The actual breakout times would change if we relaxed the assumption of perfect mixing between the wind and infall material. Our expanding shells do not exhibit the collimation of observed jets, but continue to expand laterally. To halt this expansion, the density in the envelope must fall off less steeply than in our model.Comment: 44 pages, 10 figures, accepted to Ap

At risk alcohol consumption with smoking by national background: Results from the Hispanic community health study/study of Latinos

Introduction: Tobacco smoking and binge or excess drinking are unhealthy behaviors that frequently co-occur. Studies of Hispanics/Latinos have mostly been of Mexican Americans although there are substantial differences in smoking and drinking by heritage background. Associated with co-use by 5 subpopulations. Methods: Cross-sectional data of 16,412 Hispanics/Latinos from Miami, the Bronx, Chicago and San Diego collected between 2008 and 2011 as part of the HCHS/SOL were analyzed. Smoking and alcohol consumption and demographic data were measured by self-report. Prevalence of smoking and alcohol consumption and co-use were reported. Logistic regression models examined the odds of co-use of smoking and binge or excess alcohol use by Hispanic/Latino background group. Results: Men of Cuban (10.3%), Puerto Rican (8.9%), and Mexican (8.9%) background had the highest prevalence of co-use of smoking and binge drinking compared to men of Central American (6.1%) and Dominican (6.6%) background. Women of Dominican (16.4%) and Puerto Rican (19.7%) background had the highest prevalence of binge drinking compared to women of Central American (10%) and Cuban (8%) background and Puerto Rican (34.1%) and Cuban (21.8%) women were the most likely to report current smoking compared to women of Central American (8.3%) and Mexican (10.4%) background. Acculturation was not associated with couse among men and women. Elevated depressive symptoms were positively associated with smoking and binge drinking among men, OR=1.5 [1.2–2.0], and women, OR=1.5 [1.1–2.2]. Puerto Rican women had increased odds of co-use of smoking and binge or excess drinking compared to Mexican American women, OR=3.2 [1.5–6.6]. Conclusions: Puerto Rican and Dominican Latinas and Central American and South American men have a higher prevalence of co-use

Gravitating discs around black holes

Fluid discs and tori around black holes are discussed within different approaches and with the emphasis on the role of disc gravity. First reviewed are the prospects of investigating the gravitational field of a black hole--disc system by analytical solutions of stationary, axially symmetric Einstein's equations. Then, more detailed considerations are focused to middle and outer parts of extended disc-like configurations where relativistic effects are small and the Newtonian description is adequate. Within general relativity, only a static case has been analysed in detail. Results are often very inspiring, however, simplifying assumptions must be imposed: ad hoc profiles of the disc density are commonly assumed and the effects of frame-dragging and completely lacking. Astrophysical discs (e.g. accretion discs in active galactic nuclei) typically extend far beyond the relativistic domain and are fairly diluted. However, self-gravity is still essential for their structure and evolution, as well as for their radiation emission and the impact on the environment around. For example, a nuclear star cluster in a galactic centre may bear various imprints of mutual star--disc interactions, which can be recognised in observational properties, such as the relation between the central mass and stellar velocity dispersion.Comment: Accepted for publication in CQG; high-resolution figures will be available from http://www.iop.org/EJ/journal/CQ

Competency-based (CanMEDS) residency training programme in radiology: systematic design procedure, curriculum and success factors

Based on the CanMEDS framework and the European Training Charter for Clinical Radiology a new radiology curriculum was designed in the Netherlands. Both the development process and the resulting new curriculum are presented in this paper. The new curriculum was developed according to four systematic design principles: discursiveness, hierarchical decomposition, systematic variation and satisficing (satisficing is different from satisfying; in this context, satisficing means searching for an acceptable solution instead of searching for an optimal solution). The new curriculum is organ based with integration of radiological diagnostic techniques, comprises a uniform national common trunk followed by a 2-year subspecialisation, is competency outcome based with appropriate assessment tools and techniques, and is based on regional collaboration among radiology departments. The application of the systematic design principles proved successful in producing a new curriculum approved by all authorities. The principles led to a structured, yet flexible, development process in which creative solutions could be generated and adopters (programme directors, supervisors and residents) were highly involved. Further research is needed to empirically test the components of the new curriculum

Functional microRNA screen uncovers O-linked N-acetylglucosamine transferase as a host factor modulating hepatitis C virus morphogenesis and infectivity

OBJECTIVE: Infection of human hepatocytes by the hepatitis C virus (HCV) is a multistep process involving both viral and host factors. microRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally regulate gene expression. Given that miRNAs were indicated to regulate between 30% and 75% of all human genes, we aimed to investigate the functional and regulatory role of miRNAs for the HCV life cycle. DESIGN: To systematically reveal human miRNAs affecting the HCV life cycle, we performed a two-step functional high-throughput miRNA mimic screen in Huh7.5.1 cells infected with recombinant cell culture-derived HCV. miRNA targeting was then assessed using a combination of computational and functional approaches. RESULTS: We uncovered miR-501-3p and miR-619-3p as novel modulators of HCV assembly/release. We discovered that these miRNAs regulate O-linked N-acetylglucosamine (O-GlcNAc) transferase (OGT) protein expression and identified OGT and O-GlcNAcylation as regulators of HCV morphogenesis and infectivity. Furthermore, increased OGT expression in patient-derived liver tissue was associated with HCV-induced liver disease and cancer. CONCLUSION: miR-501-3p and miR-619-3p and their target OGT are previously undiscovered regulatory host factors for HCV assembly and infectivity. In addition to its effect on HCV morphogenesis, OGT may play a role in HCV-induced liver disease and hepatocarcinogenesis

Assessing the Quality of Clinical Teachers: A Systematic Review of Content and Quality of Questionnaires for Assessing Clinical Teachers

BACKGROUND: Learning in a clinical environment differs from formal educational settings and provides specific challenges for clinicians who are teachers. Instruments that reflect these challenges are needed to identify the strengths and weaknesses of clinical teachers. OBJECTIVE: To systematically review the content, validity, and aims of questionnaires used to assess clinical teachers. DATA SOURCES: MEDLINE, EMBASE, PsycINFO and ERIC from 1976 up to March 2010. REVIEW METHODS: The searches revealed 54 papers on 32 instruments. Data from these papers were documented by independent researchers, using a structured format that included content of the instrument, validation methods, aims of the instrument, and its setting. Results : Aspects covered by the instruments predominantly concerned the use of teaching strategies (included in 30 instruments), supporter role (29), role modeling (27), and feedback (26). Providing opportunities for clinical learning activities was included in 13 instruments. Most studies referred to literature on good clinical teaching, although they failed to provide a clear description of what constitutes a good clinical teacher. Instrument length varied from 1 to 58 items. Except for two instruments, all had to be completed by clerks/residents. Instruments served to provide formative feedback ( instruments) but were also used for resource allocation, promotion, and annual performance review (14 instruments). All but two studies reported on internal consistency and/or reliability; other aspects of validity were examined less frequently. CONCLUSIONS: No instrument covered all relevant aspects of clinical teaching comprehensively. Validation of the instruments was often limited to assessment of internal consistency and reliability. Available instruments for assessing clinical teachers should be used carefully, especially for consequential decisions. There is a need for more valid comprehensive instruments