Do minimum wages raise employment? Evidence from the US retail-trade sector

This paper examines the impact of minimum wages on earnings and employment in selected branches of the retail-trade sector, 1990-2005, using county-level data on employment and a panel regression framework that allows for county-specific trends in sectoral outcomes. We focus on specific subsectors within retail trade that are identified as particularly low-wage. We find little evidence of disemployment effects once we allow for geographic-specific trends. Indeed, in many sectors the evidence points to modest (but robust) positive employment effects. (C) 2009 Elsevier B.V. All rights reserved.

The influence of market deregulation on fast food consumption and body mass index:A cross-national time series analysis

Objective
To investigate the effect of fast food consumption on mean population body mass index (BMI) and explore the possible influence of market deregulation on fast food consumption and BMI.

Methods
The within-country association between fast food consumption and BMI in 25 high-income member countries of the Organisation for Economic Co-operation and Development between 1999 and 2008 was explored through multivariate panel regression models, after adjustment for per capita gross domestic product, urbanization, trade openness, lifestyle indicators and other covariates. The possible mediating effect of annual per capita intake of soft drinks, animal fats and total calories on the association between fast food consumption and BMI was also analysed. Two-stage least squares regression models were conducted, using economic freedom as an instrumental variable, to study the causal effect of fast food consumption on BMI.

Findings
After adjustment for covariates, each 1-unit increase in annual fast food transactions per capita was associated with an increase of 0.033 kg/m2 in age-standardized BMI (95% confidence interval, CI: 0.013–0.052). Only the intake of soft drinks – not animal fat or total calories – mediated the observed association (β: 0.030; 95% CI: 0.010–0.050). Economic freedom was an independent predictor of fast food consumption (β: 0.27; 95% CI: 0.16–0.37). When economic freedom was used as an instrumental variable, the association between fast food and BMI weakened but remained significant (β: 0.023; 95% CI: 0.001–0.045).

Conclusion
Fast food consumption is an independent predictor of mean BMI in high-income countries. Market deregulation policies may contribute to the obesity epidemic by facilitating the spread of fast food.

Population-based study reveals new risk-stratification biomarker panel for Barrett's esophagus

BACKGROUND & AIMS: The risk of progression of Barrett's esophagus (BE) to esophageal adenocarcinoma (EAC) is low and difficult to calculate. Accurate tools to determine risk are needed to optimize surveillance and intervention. We assessed the ability of candidate biomarkers to predict which cases of BE will progress to EAC or high-grade dysplasia and identified those that can be measured in formalin-fixed tissues. METHODS: We analyzed data from a nested case-control study performed using the population-based Northern Ireland BE Register (1993-2005). Cases who progressed to EAC (n = 89) or high-grade dysplasia =6 months after diagnosis with BE were matched to controls (nonprogressors, n = 291), for age, sex, and year of BE diagnosis. Established biomarkers (abnormal DNA content, p53, and cyclin A expression) and new biomarkers (levels of sialyl Lewis(a), Lewis(x), and Aspergillus oryzae lectin [AOL] and binding of wheat germ agglutinin) were assessed in paraffin-embedded tissue samples from patients with a first diagnosis of BE. Conditional logistic regression analysis was applied to assess odds of progression for patients with dysplastic and nondysplastic BE, based on biomarker status. RESULTS: Low-grade dysplasia and all biomarkers tested, other than Lewis(x), were associated with risk of EAC or high-grade dysplasia. In backward selection, a panel comprising low-grade dysplasia, abnormal DNA ploidy, and AOL most accurately identified progressors and nonprogressors. The adjusted odds ratio for progression of patients with BE with low-grade dysplasia was 3.74 (95% confidence interval, 2.43-5.79) for each additional biomarker and the risk increased by 2.99 for each additional factor (95% confidence interval, 1.72-5.20) in patients without dysplasia. CONCLUSIONS: Low-grade dysplasia, abnormal DNA ploidy, and AOL can be used to identify patients with BE most likely to develop EAC or high-grade dysplasia.

Large panel-survey data demonstrated country-level and ethnic minority variation in consent for health record linkage

Objectives
To investigate individual, household and country variation in consent to health record linkage.

Study Design and Setting
Data from 50,994 individuals aged 16-74 years recruited to wave 1 of a large UK general purpose household survey (January 2009 – December 2010) were analysed using multi-level logistic regression models.

Results
Overall, 70.7% of respondents consented to record linkage. Younger age, marriage, tenure, car ownership and education were all significantly associated with consent, though there was little deviation from 70% in subgroups defined by these variables. There were small increases in consent rates in individuals with poor health when defined by self-reported long term limiting illness (adjusted OR 1.11; 95%CIs 1.06, 1.16), less so when defined by General Health Questionnaire score (adjusted OR=1.05; 95%CIs 1.00, 1.10), but the range in absolute consent rates between categories was generally less than 10%. Larger differences were observed for those of non-white ethnicity who were 38% less likely to consent (adjusted OR 0.62; 95%CIs 0.59, 0.66). Consent was higher in Scotland than England (adjusted OR 1.17; 95%CIs 1.06, 1.29) but lower in Northern Ireland (adjusted OR 0.56; 95%CIs 0.50, 0.63).

Conclusion
The modest overall level of systematic bias in consent to record linkage provides reassurance for record linkage potential in general purpose household surveys. However, the low consent rates amongst non-white ethnic minority survey respondents will further compound their low survey participation rates. The reason for the country-level variation requires further study.

Modified stiffened panel analysis methods for laser beam and friction stir welded aircraft panels

The introduction of advanced welding methods as an alternative joining process to riveting in the manufacture of primary aircraft structure has the potential to realize reductions in both manufacturing costs and structural weight. Current design and analysis methods for aircraft panels have been developed and validated for riveted fabrication. For welded panels, considering the buckling collapse design philosophy of aircraft stiffened panels, strength prediction methods considering welding process effects for both local-buckling and post-buckling behaviours must be developed and validated. This article reports on the work undertaken to develop analysis methods for the crippling failure of stiffened panels fabricated using laser beam and friction stir welding. The work assesses modifications to conventional analysis methods and finite-element analysis methods for strength prediction. The analysis work is validated experimentally with welded single stiffener crippling specimens. The experimental programme has demonstrated the potential static strength of laser beam and friction stir welded sheet-stiffener joints for post-buckling panel applications. The work undertaken has demonstrated that the crippling behaviour of welded stiffened panels may be analysed considering standard-buckling behaviour. However, stiffened panel buckling analysis procedures must be altered to account for the weld joint geometry and process altered material properties. © IMechE 2006.

Parenting practices in Northern Ireland: evidence from the Northern Ireland Household Panel Survey

The impact of parental child-rearing practices on child outcomes has been the subject of much research and debate for many years. Studies carried out within a variety of disciplines and across a number of different countries in the world have indicated that parents tend to use a different pattern of rearing their sons than their daughters, and that child-rearing practices are related to the gender of the parent, as well as to the age and developmental stage of the child. However, there has been little research in Northern Ireland on child-rearing behaviours. In order to address this shortfall, this paper presents an analysis of parents’ perceptions of their interactions with their children. Data from Wave 3 of the Northern Ireland Household Panel Survey were analysed to explore aspects of ‘‘negative’’ parenting practices (arguing, yelling and use of physical punishment) as well as ‘‘positive’’ parenting practices (talking, praising and hugging). The participants were all parents (aged 16 years and over) with children under the age of 16 years living in the same household. Each parent reported his/her interaction with each child (up to a maximum of six children), and in total 1,629 responses were recorded. The results of the research supported previous findings from the United Kingdom and elsewhere, and indicated that the parenting styles of respondents in Northern Ireland were indeed related to the gender and age of the children and to the gender of the parents. The survey found that parents in Northern Ireland tend to have a harsher, more negative style of parenting boys than girls and that children in their teenage years have fewer positive interactions with their parents than younger children. The same parents and children will be followed up in 2007 in order to provide a longitudinal analysis of parent/child relationships in Northern Ireland.

Relationship between biomedical catheter surface properties and lubricity as determined using textural analysis and multiple regression analysis

In this study, the surface properties of and work required to remove 12 commercially available and developmental catheters from a model biological medium (agar), a measure of catheter lubricity, were characterised and the relationships between these properties were examined using multiple regression and correlation analysis. The work required for removal of catheter sections (7 cm) from a model biological medium (1% w/w agar) were examined using tensile analysis. The water wettability of the catheters were characterised using dynamic contact angle analysis, whereas surface roughness was determined using atomic force microscopy. Significant differences in the ease of removal were observed between the various catheters, with the silicone-based materials generally exhibiting the greatest ease of removal. Similarly, the catheters exhibited a range of advancing and receding contact angles that were dependent on the chemical nature of each catheter. Finally, whilst the microrugosities of the various catheters differed, no specific relationship to the chemical nature of the biomaterial was apparent. Using multiple regression analysis, the relationship between ease of removal, receding contact angle and surface roughness was defined as: Work done (N mm) 17.18 + 0.055 Rugosity (nm)-0.52 Receding contact angle (degrees) (r = 0.49). Interestingly, whilst the relationship between ease of removal and surface roughness was significant (r = 0.48, p = 0.0005), in which catheter lubricity increased as the surface roughness decreased, this was not the case with the relationship between ease of removal and receding contact angle (r = -0.18, p > 0.05). This study has therefore uniquely defined the contributions of each of these surface properties to catheter lubricity. Accordingly, in the design of urethral catheters. it is recommended that due consideration should be directed towards biomaterial surface roughness to ensure maximal ease of catheter removal. Furthermore, using the method described in this study, differences in the lubricity of the various catheters were observed that may be apparent in their clinical use. (C) 2003 Elsevier Ltd. All rights reserved.

A panel of single locus minisatellite DNA probes for application to problems in salmonid aquaculture

Eleven minisatellite DNA locus specific probes, isolated from Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) partial genomic DNA libraries, were tested for cross-hybridization to eleven other salmonid species, i.e. sockeye salmon (Oncorhynchus nerka); coho salmon (O. kisutch), chum salmon (O. keta); pink salmon (O. gorbuscha); chinook salmon (O. tshawytscha); rainbow trout (O. mykiss); brook trout (Salvelinus fontinalis); Arctic charr (S. alpinus); grayling (Thymallus thymallus); huchen (Hucho hucho); pollan (Coregonus autumnalis). Simple single locus profiles for each of these species were revealed by, from two to ten SLPs. These markers are likely to be of great value in addressing several problems in aquaculture of these species.

The Characterization of Friction Stir Welding Process Effects on Stiffened Panel Buckling Performance

The introduction of advanced welding methods as an alternative joining process to riveting in the manufacture of primary aircraft structure has the potential to realize reductions in both manufacturing costs and structural weight. However, welding processes can introduce undesirable residual stresses and distortions in the final fabricated components, as well as localized loss of mechanical properties at the weld joints. The aim of this research is to determine and characterize the key process effects of advanced welding assembly methods on stiffened panel static strength performance. This in-depth understanding of the relationships between welding process effects and buckling and collapse strength is required to achieve manufacturing cost reductions without introducing structural analysis uncertainties and hence conservative over designed welded panels. This current work is focused at the sub-component level and examines the static strength of friction stir welded multi stiffener panels. The undertaken experimental and computational studies have demonstrated that local skin buckling is predominantly influenced by the magnitude of welding induced residual stresses and associated geometric distortions, whereas panel collapse behavior is sensitive to the lateral width of the physically joined skin and stiffener flange material, the strength of material in the Heat Affected Zone as well as the magnitude of the welding induced residual stresses. Copyright © 2006 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.


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