How do systematic reviews incorporate risk of bias assessments into the synthesis of evidence? A methodological study

Background: Systematic reviews (SRs) are expected to critically appraise included studies and privilege those at lowest risk of bias (RoB) in the synthesis. This study examines if and how critical appraisals inform the synthesis and interpretation of evidence in SRs.<p></p> Methods: All SRs published in March–May 2012 in 14 high-ranked medical journals and a sample from the Cochrane library were systematically assessed by two reviewers to determine if and how: critical appraisal was conducted; RoB was summarised at study, domain and review levels; and RoB appraisals informed the synthesis process.<p></p> Results: Of the 59 SRs studied, all except six (90%) conducted a critical appraisal of the included studies, with most using or adapting existing tools. Almost half of the SRs reported critical appraisal in a manner that did not allow readers to determine which studies included in a review were most robust. RoB assessments were not incorporated into synthesis in one-third (20) of the SRs, with their consideration more likely when reviews focused on randomised controlled trials. Common methods for incorporating critical appraisals into the synthesis process were sensitivity analysis, narrative discussion and exclusion of studies at high RoB. Nearly half of the reviews which investigated multiple outcomes and carried out study-level RoB summaries did not consider the potential for RoB to vary across outcomes.<p></p> Conclusions: The conclusions of the SRs, published in major journals, are frequently uninformed by the critical appraisal process, even when conducted. This may be particularly problematic for SRs of public health topics that often draw on diverse study designs

Childhood psychological predictors of unemployment: Evidence from four cohort studies

Recent research in economics and psychology has examined the childhood noncognitive skills which predict future economic success. However, there has been relatively little research on whether these skills predict future unemployment. This thesis uses data from four cohort studies (total N = 47,328) from Great Britain and the United States to examine how lifetime trajectories of unemployment are affected by childhood differences in self-control (chapter 3), conscientiousness (4), and mental health (5-6). These are some of the first studies to examine how pre-labor market measures of these psychological characteristics prospectively predict future unemployment. Chapters 3, 5 and 6 are the first studies to examine how early psychological characteristics interact with recessions to produce differential unemployment outcomes. After adjusting for cognitive ability and key sociodemographic indicators (e.g. gender, SES), all three of these psychological characteristics are found to predict future unemployment. The effects are statistically significant and economically meaningful, comparable in magnitude to the effects of intelligence. Chapter 3 shows that childhood with poor self-control were disproportionately more likely than their more self-controlled peers to become unemployed during the 1980s UK recession, and chapters 5 and 6 find a similar effect for children with high psychological distress compared to their less distressed peers during the 1980s UK recession and 2007 US recession. These studies demonstrate the value of using psychological research to examine economic outcomes. The chief policy implication is that interventions which improve childhood levels of self-control, conscientiousness and mental health may be an effective way to reduce future population unemployment levels. In the short term, remediation programs which take into account individual psychological differences may improve the efficacy of unemployment interventions, particularly during recessions when certain groups are more likely than others to become unemployed

Synthetic Studies towards Trichothecene Mycotoxins

This thesis describes the first synthesis of a tetrahydroxylated trichothecene mycotoxin, 3alpha,4beta,8alpha,15-tetra-hydroxy-12,13-epoxy trichothec-9-ene (T-2 tetraol) (19), as its tetraacetate (Neosolaniol diacetate) (319) (Scheme 86). The synthetic strategy consists of five key elements. 1) formation of the cis fused AB ring system by a Diels-Alder cycloaddition; 2) formation of ring C by an intramolecular aldol reaction; 3) creation of the 3alpha,4beta-diol system of ring C by a stereoselective a-oxygenation/reduction protocol; 4) ring A enone formation via a regiospecific thermodynamically controlled alpha-selenylation, and 5) regio and stereospecific reduction of this enone to the required alpha-alcohol. As part of a concerted effort towards this molecule, this thesis reports a model study aimed at achieving the 3alpha,4beta-diol system of ring C (Scheme 52). The partial synthesis of 8-keto-anguidine (297) described herein (Chapter 2.2) allowed a study (Chapter 2.3) of the stereochemical outcome of the reduction of ring A enones by various reducing agents: it is shown that L-Selectride reduces such enones stereospecifically to 8alpha-alcohols. Attempted completion of an approach to deoxynivalenol (6) (Chapter 2.5) is discussed. The termination of this route is attributed to competing intramolecular processes which prevented successful olefination of the ketone (362)

DC-CAD : a new software solution for product design

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Vita.Includes bibliographical references.Many computer aided design (CAD) software packages focus on detailed design and not on early stage, conceptual design. The ability to conceptualize and sketch early versions of a product solution is currently limited to paper and pencil or to inadequate computer-aided industrial design programs (CAID) that focus mainly on surface design, not product design. Working on a design as a group also poses problems since the team can be geographically distributed. In an attempt to address the current inadequacies of CAD systems for distributed conceptual design, my thesis proposes a vision for a new CAD program, DC-CAD. This vision anticipates network-orientated conceptual design, and encompasses capabilities for multiple users to collaborate simultaneously on design, compare & evaluate concept sketches, comment on designs and merge changes from other designers, transfer data to detailed design CAD programs, and record concept changes over time. MIT's Product Engineering Class (2.009) was used as the basis for conceiving the software system. By analyzing design challenges that arose during the course, new software features are suggested to mitigate such problems.(cont.) The end result is a clear vision for a new program, DC-CAD, and a storyboard example of how it could be used in a futuristic 2.009 setting. The thesis closes with recommendations on how to pursue the implementation and realization of such a CAD system.by Mark D. Egan.S.B

How does money influence health?

This study looks at hundreds of theories to consider how income influences health. There is a graded association between money and health – increased income equates to better health. But the reasons are debated.<p></p> Researchers have reviewed theories from 272 wide-ranging papers, most of which examined the complex interactions between people’s income and their health throughout their lives.<p></p> Key points<p></p> This research identifies four main ways money affects people’s wellbeing:<p></p> Material: Money buys goods and services that improve health. The more money families have, the better the goods they can buy.<p></p> Psychosocial: Managing on a low income is stressful. Comparing oneself to others and feeling at the bottom of the social ladder can be distressing, which can lead to biochemical changes in the body, eventually causing ill health.<p></p> Behavioural: For various reasons, people on low incomes are more likely to adopt unhealthy behaviours – smoking and drinking, for example – while those on higher incomes are more able to afford healthier lifestyles.<p></p> Reverse causation (poor health leads to low income): Health may affect income by preventing people from taking paid employment. Childhood health may also affect educational outcomes, limiting job opportunities and potential earnings

Childhood self-control and adult pension participation

Self-control problems have been proposed as a key reason for low pension saving rates, yet evidence of this link remains scarce. We test the association between childhood self-control and adult pension participation using data from 14,223 individuals from two nationally-representative British cohorts. We find that a 1 standard deviation increase in self-control predicts a 4–5 percentage point higher probability of having a pension. Mediation analysis shows that about 50–60 percent of this association is explained by the contribution of self-control to a range of factors (e.g. education, economic status, home-ownership) which are associated with pension uptake throughout adulthood

Childhood psychological distress and youth unemployment: evidence from two British cohort studies

The effect of childhood mental health on later unemployment has not yet been established. In this article we assess whether childhood psychological distress places young people at high risk of subsequent unemployment and whether the presence of economic recession strengthens this relationship. This study was based on 19,217 individuals drawn from two nationally-representative British prospective cohort studies; the Longitudinal Study of Young People in England (LSYPE) and the National Child Development Study (NCDS). Both cohorts contain rich contemporaneous information detailing the participants' early life socioeconomic background, household characteristics, and physical health. In adjusted analyses in the LSYPE sample (N = 10,232) those who reported high levels of distress at age 14 were 2 percentage points more likely than those with low distress to be unemployed between ages 16 and 21. In adjusted analyses of the NCDS sample (N = 8985) children rated as having high distress levels by their teachers at age 7 and 11 were 3 percentage points more likely than those with low distress to be unemployed between ages 16 and 23. Our examination of the 1980 UK recession in the NCDS cohort found the difference in average unemployment level between those with high versus low distress rose from 2.6 pct points in the pre-recession period to 3.9 points in the post-recession period. These findings point to a previously neglected contribution of childhood mental health to youth unemployment, which may be particularly pronounced during times of economic recession. Our findings also suggest a further economic benefit to enhancing the provision of mental health services early in life

Pupil slicer design for the NASA-NSF extreme precision Doppler spectrograph concept WISDOM

The WIYN Spectrograph for Doppler Monitoring (WISDOM) was a concept responding to NASA's solicitation for an extreme precision radial velocity instrument for the 3.5 meter WIYN telescope on Kitt Peak in Arizona. In order to meet the spectral resolution requirement of R = 110,000 while maintaining good throughput and a manageable beam diameter, the front end design of the instrument employed a pupil slicing technique wherein a collimated beam is sliced and fed to six separate fibers. This paper presents the optical and mechanical design of the pupil slicer subassembly, a unique method of dealing with thermally induced defocus error, and the methods and results of aligning a prototype

MSX versus IRAS Two-Color Diagrams and the CSE-Sequence of Oxygen-Rich Late-Type Stars

We present MSX two-color diagrams that can be used to characterize circumstellar environments of sources with good quality MSX colors in terms of IRAS color regions for oxygen-rich stars. With these diagrams we aim to provide a new tool that can be used to study circumstellar environments and to improve detection rates for targeted surveys for circumstellar maser emission similar to the IRAS two-color diagram. This new tool is especially useful for regions in the sky where IRAS was confused, in particular in the Galactic plane and bulge region. Unfortunately, using MSX colors alone does not allow to distinguish between carbon-rich and oxygen-rich objects. An application of this tool on 86 GHz SiO masers shows that for this type of masers an instantaneous detection rate of 60% to 80% can be achieved if target sources are selected according to MSX color (region). Our investigations may have revealed an error in the MSX point source catalog version 2.3. That is, the photometry of the 21.3 $\mu$m (MSX E filter) band for most weak 8.28 $\mu$m (or MSX A filter) band sources seems off by about a factor two (0.5--1 magnitude too bright).Comment: accepted to Astrophysical Journal, 11 pages, 11 figs of which 1 in colo