Context affects student thinking about sources of uncertainty in classical and quantum mechanics

Measurement uncertainty is an important topic in the undergraduate laboratory curriculum. Previous research on student thinking about experimental measurement uncertainty has focused primarily on introductory-level students' procedural reasoning about data collection and interpretation. In this paper, we extended this prior work to study upper-level students' thinking about sources of measurement uncertainty across experimental contexts, with a particular focus on classical and quantum mechanics contexts. We developed a survey to probe students' thinking in the generic question ``What comes to mind when you think about measurement uncertainty in [classical/quantum] mechanics?'' as well as in a range of specific experimental scenarios. We found that students primarily focused on limitations of the experimental setup in classical mechanics and principles of the underlying physics theory in quantum mechanics. Our results suggest that students need careful scaffolding to identify principles in appropriate classical experimental contexts and limitations in appropriate quantum experimental contexts. We recommend that future research probe how instruction in both classical and quantum contexts can help students better understand the range of sources of uncertainty present in classical and quantum experiments.Comment: 15 pages, 8 figure

New perspectives on student reasoning about measurement uncertainty: More or better data

Uncertainty is an important and fundamental concept in physics education. Students are often first exposed to uncertainty in introductory labs, expand their knowledge across lab courses, and then are introduced to quantum mechanical uncertainty in upper-division courses. This study is part of a larger project evaluating student thinking about uncertainty across these contexts. In this research, we investigate advanced physics student thinking about uncertainty by asking them conceptual questions about how a hypothetical distribution of measurements would change if `more' or `better' data were collected in four different experimental scenarios. The scenarios include both classical and quantum experiments, as well as experiments that theoretically result in an expected single value or an expected distribution. This investigation is motivated by our goal of finding insights into students' potential point- and set-like thinking about uncertainty and of shining light on the limitations of those binary paradigms.Comment: 15 pages, 5 figures, accepted to Physical Review Physics Education Researc

PSYCHOSOCIAL FACTORS AND MOBILE HEALTH INTERVENTION: IMPACT ON LONG-TERM OUTCOMES AFTER LUNG TRANSPLANTATION

Identifying and intervening on modifiable risk factors may improve outcomes in lung transplantation (LTx), which, despite recent improvements, remain suboptimal. Evidence suggests that two modifiable risk factors, psychiatric disorders and nonadherence, may improve LTx outcomes in the short-term; however, neither has been explored in the long-term. Therefore, the overarching goal of this dissertation was to determine the long-term impact of these modifiable risk factors and intervention to attenuate them. First, we examined the relationship of pre- and early post-transplant psychiatric disorders on LTx-related morbidity and mortality for up to 15 years post-LTx. Our sample included 155 1-year LTx survivors enrolled in a prospective study of mental health post- LTx. We found that depression during the first year post-LTx increased risk of BOS, mortality and graft loss by nearly twofold, and that pre-transplant depression and pre- and post-transplant anxiety were not associated with clinical outcomes. Next, we examined the impact of a mobile health intervention designed to promote adherence to the post-LTx regimen, PocketPATH, on long-term LTx-related morbidity, mortality and nonadherence. We conducted two follow-up studies to the original yearlong randomized controlled trial in which participants assigned to PocketPATH showed improved adherence to the regimen, relative to usual care. Among the 182 LTx recipients (LTxRs) who survived the original trial, we found that PocketPATH had a protective indirect effect on mortality by promoting LTxRs’ communication with the LTx team during the first year. Among the 104 LTxRs who completed the follow-up assessment, we found that PocketPATH’s adherence benefits over the first year were not sustained into the long-term, although LTxRs assigned to PocketPATH were more likely than LTxRs assigned to usual care to perform the home self-care tasks of the regimen at follow-up. Median time since LTx for participants in both follow-up studies was 4.2 years (range, 2.8-5.7 years). This dissertation presents an important first step toward identifying and intervening on modifiable risk factors to improve long-term LTx outcomes. Mobile health technologies offer limitless potential to target these risk factors and others. More work is needed to determine specific features and long-term patient engagement strategies that will optimize and sustain intervention effectiveness

Sickness presenteeism in Spanish-born and immigrant workers in Spain

<p>Abstract</p> <p><b>Background</b></p> <p>Previous studies have shown that immigrant workers face relatively worse working and employment conditions, as well as lower rates of sickness absence than native-born workers. This study aims to assess rates of sickness presenteeism in a sample of Spanish-born and foreign-born workers according to different characteristics.</p> <p>Methods</p> <p>A cross-sectional survey was conducted amongst a convenience sample of workers (Spanish-born and foreign-born), living in four Spanish cities: Barcelona, Huelva, Madrid and Valencia (2008-2009). Sickness presenteeism information was collected through two items in the questionnaire ("Have you had health problems in the last year?" and "Have you ever had to miss work for any health problem?") and was defined as worker who had a health problem (answered yes, first item) and had not missed work (answered no, second item). For the analysis, the sample of 2,059 workers (1,617 foreign-born) who answered yes to health problems was included. After descriptives, logistic regressions were used to establish the association between origin country and sickness presenteeism (adjusted odds ratios aOR; 95% confidence interval 95%CI). Analyses were stratified per time spent in Spain among foreign-born workers.</p> <p>Results</p> <p>All of the results refer to the comparison between foreign-born and Spanish-born workers as a whole, and in some categories relating to personal and occupational conditions. Foreign-born workers were more likely to report sickness presenteeism compared with their Spanish-born counterparts, especially those living in Spain for under 2 years [Prevalence: 42% in Spanish-born and 56.3% in Foreign-born; aOR 1.77 95%CI 1.24-2.53]. In case of foreign-born workers (with time in Spain < 2 years), men [aOR 2.31 95%CI 1.40-3.80], those with university studies [aOR 3.01 95%CI 1.04-8.69], temporary contracts [aOR 2.26 95%CI 1.29-3.98] and salaries between 751-1,200€ per month [aOR 1.74 95% CI 1.04-2.92] were more likely to report sickness presenteeism. Also, recent immigrants with good self-perceived health and good mental health were more likely to report presenteeism than Spanish-born workers with the same good health indicators.</p> <p>Conclusions</p> <p>Immigrant workers report more sickness presenteeism than their Spanish-born counterparts. These results could be related to precarious work and employment conditions of immigrants. Immigrant workers should benefit from the same standards of social security, and of health and safety in the workplace that are enjoyed by Spanish workers.</p

Comprehensive ECG reference intervals in C57BL/6N substrains provide a generalizable guide for cardiac electrophysiology studies in mice.

Reference ranges provide a powerful tool for diagnostic decision-making in clinical medicine and are enormously valuable for understanding normality in pre-clinical scientific research that uses in vivo models. As yet, there are no published reference ranges for electrocardiography (ECG) in the laboratory mouse. The first mouse-specific reference ranges for the assessment of electrical conduction are reported herein generated from an ECG dataset of unprecedented scale. International Mouse Phenotyping Consortium data from over 26,000 conscious or anesthetized C57BL/6N wildtype control mice were stratified by sex and age to develop robust ECG reference ranges. Interesting findings include that heart rate and key elements from the ECG waveform (RR-, PR-, ST-, QT-interval, QT corrected, and QRS complex) demonstrate minimal sexual dimorphism. As expected, anesthesia induces a decrease in heart rate and was shown for both inhalation (isoflurane) and injectable (tribromoethanol) anesthesia. In the absence of pharmacological, environmental, or genetic challenges, we did not observe major age-related ECG changes in C57BL/6N-inbred mice as the differences in the reference ranges of 12-week-old compared to 62-week-old mice were negligible. The generalizability of the C57BL/6N substrain reference ranges was demonstrated by comparison with ECG data from a wide range of non-IMPC studies. The close overlap in data from a wide range of mouse strains suggests that the C57BL/6N-based reference ranges can be used as a robust and comprehensive indicator of normality. We report a unique ECG reference resource of fundamental importance for any experimental study of cardiac function in mice

Correction to: Cluster identification, selection, and description in Cluster randomized crossover trials: the PREP-IT trials

An amendment to this paper has been published and can be accessed via the original article

Psychiatric disorders as risk factors for adverse medical outcomes after solid organ transplantation

PURPOSE OF REVIEW: Given that the prevalence of psychiatric disorders in transplant candidates and recipients is substantially higher than in the general population, and that linkages between psychiatric disorders and medical outcomes for nontransplant-related diseases have been established, it is important to determine whether psychiatric disorders predict posttransplant medical outcomes. RECENT FINDINGS: Most research has focused on the association between depression (both pretransplant and posttransplant) and posttransplant mortality. Some research has examined transplant-related morbidity outcomes, such as graft rejection, posttransplant malignancies, and infection. However, methodological limitations make it difficult to compare existing studies in this literature directly. Overall, the studies presented in this review indicate that psychiatric distress occurring in the early transplant aftermath bears a stronger relationship to morbidity and mortality outcomes than psychiatric distress occurring before transplant. SUMMARY: The literature on the impact of psychiatric conditions on the morbidity and mortality of solid organ transplant recipients remains inconclusive. More research is needed in order to investigate these associations among a broader range of psychiatric predictors, morbidity outcomes, and recipient populations. Until evidence suggests otherwise, we recommend frequent monitoring of psychiatric symptoms during the first year after transplantation to aid in early identification and treatment during this critical period of adjustment. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins

Variability of genome-wide DNA methylation and mRNA expression profiles in reproductive and endocrine disease related tissues

Genome-wide-association-studies in the fields of reproductive medicine and endocrinology are yielding robust genetic variants associated with disease. Integrated genomic, transcriptomic and epigenomic molecular profiling studies are a common methodology to understand the biological pathways perturbed by these variants. However, molecular profiling resources do not include the tissue most relevant to many female reproductive traits, endometrium, whilst the parameters influencing variability of results from its molecular profiling is unclear. We investigated the sources of variability of DNA-methylation and RNA-expression profiles in n=135 endometrium, endometriotic disease tissue (endometriosis) and subcutaneous abdominal fat samples from 24 women, quantifying between-individual, within-tissue (cellular heterogeneity) and technical variation. DNA samples (n=96) were analysed using Illumina-450Kmethylation and RNA (n=39) using H12-expression arrays. Variance-component-analyses showed that for the top 10-50% variable DNA methylation/RNA expression sites, between-individual variation far exceeded within-tissue and technical variation. Menstrual-phase accounted for most variability in methylation/expression patterns in endometrium (Pm=7.8x10-3, Pe=8.4x10-5) but not in fat and endometriotic tissue; age was significantly associated with DNA-methylation profile of endometrium (Pm=9x10-5) and endometriotic-disease tissue (Pm=2.4x10-5); and smoking in adipose tissue (Pm=1.8x10-3). Hierarchical-cluster-analysis showed significantly different methylation signatures between endometrium and endometriotic tissue enriched for WNT signaling, angiogenesis, cadherin signalling, and gonadotropin-releasing-hormone-receptor pathways. Differential DNA methylation/expression analyses suggested detection of a limited number of sites with large fold changes (FC>4), but power calculations accounting for different sources of variability showed that for robust detection >500 tissue samples are required. These results enable appropriate study design for large-scale expression and methylation tissue-based profiling relevant to many reproductive and endocrine traits