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Self-selection
Selected AbstractsAffinity-Based Protein Surface Pattern Formation by Ligand Self-Selection from Mixed Protein SolutionsADVANCED FUNCTIONAL MATERIALS, Issue 19 2009Manish Dubey Abstract Photolithographically prepared surface patterns of two affinity ligands (biotin and chloroalkane) specific for two proteins (streptavidin and HaloTag, respectively) are used to spontaneously form high-fidelity surface patterns of the two proteins from their mixed solution. High affinity protein-surface self-selection onto patterned ligands on surfaces exhibiting low non-specific adsorption rapidly yields the patterned protein surfaces. Fluorescence images after protein immobilization show high specificity of the target proteins to their respective surface patterned ligands. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) imaging further supports the chemical specificity of streptavidin and HaloTag for their surface patterned ligands from mixed protein solutions. However, ToF-SIMS did detect some non-specific adsorption of bovine serum albumin, a masking protein present in excess in the adsorbing solutions, on the patterned surfaces. Protein amino acid composition, surface coverage, density, and orientation are important parameters that determine the relative ToF-SIMS fragmentation pattern yields. ToF-SIMS amino acid-derived ion fragment yields summed to produce surface images can reliably determine which patterned surface regions contain bound proteins, but do not readily discriminate between different co-planar protein regions. Principal component analysis (PCA) of these ToF-SIMS data, however, improves discrimination of ions specific to each protein, facilitating surface protein pattern identification and image contrast. [source] Discussion of Self-Selection and the Forecasting Abilities of Female Equity AnalystsJOURNAL OF ACCOUNTING RESEARCH, Issue 2 2010PAOLA SAPIENZA First page of article [source] Bias from Farmer Self-Selection in Genetically Modified Crop Productivity Estimates: Evidence from Indian DataJOURNAL OF AGRICULTURAL ECONOMICS, Issue 1 2007Benjamin Crost Q12; D81 Abstract In the continuing debate over the impact of genetically modified (GM) crops on farmers of developing countries, it is important to accurately measure magnitudes such as farm-level yield gains from GM crop adoption. Yet most farm-level studies in the literature do not control for farmer self-selection, a potentially important source of bias in such estimates. We use farm-level panel data from Indian cotton farmers to investigate the yield effect of GM insect-resistant cotton. We explicitly take into account the fact that the choice of crop variety is an endogenous variable which might lead to bias from self-selection. A production function is estimated using a fixed-effects model to control for selection bias. Our results show that efficient farmers adopt Bacillus thuringiensis (Bt) cotton at a higher rate than their less efficient peers. This suggests that cross-sectional estimates of the yield effect of Bt cotton, which do not control for self-selection effects, are likely to be biased upwards. However, after controlling for selection bias, we still find that there is a significant positive yield effect from adoption of Bt cotton that more than offsets the additional cost of Bt seed. [source] Effectiveness of a smoking cessation intervention in older adultsADDICTION, Issue 1 2007Robert J. Tait ABSTRACT Aims To: (a) identify characteristics of older smokers considering cessation of smoking; (b) evaluate a cessation intervention plus access to nicotine replacement therapy (NRT); (c) identify predictors of those who successfully quit; and (d) evaluate the effectiveness of the intervention in those aged , 75 years. Design Self-selection of: (a) a cessation of smoking programme; or (b) ongoing smoking. Setting Teaching hospital, Perth, Western Australia. Participants A larger study recruited smokers and never smokers: from this the 215 community-dwelling smokers (, 5 cigarettes/day) aged , 68 years (171 males) were enrolled. Intervention Brief intervention with telephone support and access to NRT versus no intervention. Measurements (a) Profile of older adults planning to quit smoking compared with continuing smokers; (b) cessation at 6 months defined as 30-day point prevalence validated via expired carbon monoxide; and (c) factors predictive of successful cessation. Findings There were 165 intervention participants. Compared with the 50 continuing smokers, participants in the intervention were younger and had significantly less years of regular smoking, more previous quit attempts and greater nicotine dependence scores. At 6 months, the point prevalence of ex-smokers was 25% (n = 42) with 20% (n = 33) being abstinent throughout the study. No continuing smoker had ceased smoking. Among the intervention group, logistic regression showed that those who used NRT (OR 4.36), were male (OR 3.17), had higher anxiety (OR 1.67) or rejected ,more colds and coughs' as a reason for quitting (OR 2.91) were more likely to be successful quitters. Of those aged , 75 years (n = 77), 25% matched cessation criteria. Conclusions Older smokers can be engaged successfully in a brief intervention plus NRT as aids to cessation of smoking. The intervention was also effective in the older subgroup of participants. Social factors may provide an additional means of motivating older smokers to quit. [source] Self-selection and Earnings of Migrants: Evidence from Rural ChinaASIAN ECONOMIC JOURNAL, Issue 1 2010Zheren Wu J24; J31; O15; R23 Using data from a rural household survey in China, this paper explores the link between employment choice (nonworking, local farm work, local nonfarm work and migratory work) and migrant earnings. We find significant self-selection in migration. Youths, men, better-educated individuals and those in good health are more likely to migrate. In terms of unobserved characteristics, we find positive selection in migration to be related to the alternatives of not working and local farm work, and negative selection to be related to local nonfarm work. Controlling for self-selection, the wage returns to gender (male), education and health are lower than those obtained from OLS, and the returns to experience are higher. More importantly, we find different self-selection between individuals who have moved as pioneers and migrants from households in which other members have already migrated. [source] Labor productivity of small and large manufacturing firms: the case of TaiwanCONTEMPORARY ECONOMIC POLICY, Issue 3 2000M. Hsu This work studies the factors influencing the labor productivity of small and medium-sized enterprises (SMEs) and large firms using Taiwan as a case study. A special emphasis is placed on two possible international channels: exports and foreign direct investment (FDI). Different from conventional studies, we employ the two-stage switching regressions to correct the firm-size effect on labor productivity and estimate labor productivity for SMEs and large firms. The main findings are as follows. First, the estimates of the selectivity variable are statistically significant for both SMEs and large firms, supporting the hypothesis of correcting the effect of firm-size truncation. Second, while a larger trade intensity significantly increases the labor productivity of SMEs, it deteriorates significantly that of large firms. Third, FDI enhances the labor productivity of SMEs internally, whereas it has a negative spillover on that of other small and large firms in the industry. While the first outcome lends supports to the role of self-selection, the remaining stands in sharp contrast to conventional wisdom. [source] Participation and Impact of Poverty-oriented Public Works Projects in Rural MalawiDEVELOPMENT POLICY REVIEW, Issue 2 2002Ephraim W. Chirwa This article reports on factors influencing participation in the poverty-oriented public works programme in rural Malawi and analyses the determinants of the revealed positive socio-economic impact among the participants. The programme targets poor households through self-selection by offering a wage below the official minimum for rural areas. The empirical results show that most participants are poor and with little education. Probability of particpation is higher for members of female-headed households and households with longer periods of food insecurity, excess supply of labour, few assets and reservation wages below the wage offered in the programme. Taking account of selectivity bias, the impact of the programme increases with the gender (female) of participants and the numbers per household participating. [source] Immigration to the Land of RedistributionECONOMICA, Issue 308 2010TITO BOERI Negative perceptions about migrants in Europe are driven by concerns that foreigners abuse welfare. Paradoxically, instruments of social inclusion are becoming weapons of mass exclusion. We compare evidence on welfare access and the net fiscal position of migrants with perceptions based on a largely unexploited database (EU-SILC). We find no evidence that legal migrants, notably skilled migrants, are net recipients of transfers from the state. However, there is evidence of ,residual dependency' on non-contributory transfers and self-selection of unskilled migrants in the countries with the most generous welfare states. Alternative strategies to unbundle migration from welfare access are discussed. [source] Targeting fuel poverty in England: is the government getting warm?FISCAL STUDIES, Issue 3 2002Tom Sefton Abstract This paper examines the cost-effectiveness of the new Home Energy Efficiency Scheme (HEES), a key component of the UK government's Fuel Poverty Strategy. The impact on the fuel poverty gap is simulated using data on a large-scale and representative sample of households in England. The scope for improving the scheme's targeting is considered by examining the optimal allocation of grants between households. The extent to which these potential gains might be achieved in practice using pragmatic criteria for distributing grants, and the implications of taking into account the dynamics of fuel poverty and the self-selection of grant applicants, are also explored. The current scheme is unlikely to have a very significant impact on fuel poverty, and considerable gains could be achieved by redesigning HEES, although the paper also highlights the difficulties involved in efficient targeting, including some additional complications not encountered in the analysis of more traditional anti-poverty measures. [source] Affinity-Based Protein Surface Pattern Formation by Ligand Self-Selection from Mixed Protein SolutionsADVANCED FUNCTIONAL MATERIALS, Issue 19 2009Manish Dubey Abstract Photolithographically prepared surface patterns of two affinity ligands (biotin and chloroalkane) specific for two proteins (streptavidin and HaloTag, respectively) are used to spontaneously form high-fidelity surface patterns of the two proteins from their mixed solution. High affinity protein-surface self-selection onto patterned ligands on surfaces exhibiting low non-specific adsorption rapidly yields the patterned protein surfaces. Fluorescence images after protein immobilization show high specificity of the target proteins to their respective surface patterned ligands. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) imaging further supports the chemical specificity of streptavidin and HaloTag for their surface patterned ligands from mixed protein solutions. However, ToF-SIMS did detect some non-specific adsorption of bovine serum albumin, a masking protein present in excess in the adsorbing solutions, on the patterned surfaces. Protein amino acid composition, surface coverage, density, and orientation are important parameters that determine the relative ToF-SIMS fragmentation pattern yields. ToF-SIMS amino acid-derived ion fragment yields summed to produce surface images can reliably determine which patterned surface regions contain bound proteins, but do not readily discriminate between different co-planar protein regions. Principal component analysis (PCA) of these ToF-SIMS data, however, improves discrimination of ions specific to each protein, facilitating surface protein pattern identification and image contrast. [source] A Random Utility Model of Environmental EquityGROWTH AND CHANGE, Issue 1 2000Diane Hite Past attempts to uncover evidence that economically disadvantaged groups are unjustly exposed to environmental disamenities have failed to take into account self-selection behavior of individuals or groups of individuals. For instance, when choosing a place to live, households may be trading environmental quality for other housing, neighborhood, and location characteristics they care about. Previous literature on environmental justice has investigated location choice of polluting industries, but fails to account for consumer self-selection in housing markets. This paper thus focuses on location choice of individuals based on observed housing transactions. From the results of a random utility model, a test is proposed that incorporates the no-envy concept of economic equity. The results support a finding for environmental discrimination with respect to African American households, but do not support the hypothesis that poor households in general are unfairly exposed to environmental disamenities. [source] Non-pecuniary returns to higher education: the effect on smoking intensity in the UKHEALTH ECONOMICS, Issue 8 2010Massimiliano Bratti Abstract This paper investigates whether higher education (HE) produces non-pecuniary returns via a reduction in the intensity of consumption of health-damaging substances. In particular, it focuses on current smoking intensity of the British individuals sampled in the 29-year follow-up survey of the 1970 British Cohort Study. We estimate endogenous dummy ordinal response models for cigarette consumption and show that HE is endogenous with respect to smoking intensity and that even when endogeneity is accounted for, HE is found to have a strong negative effect on smoking intensity. Moreover, pecuniary channels, such as occupation and income, mediate only a minor part of the effect of HE. Our results are robust to modelling individual self-selection into current smoking participation (at age 29) and to estimating a dynamic model in which past smoking levels affect current smoking levels. Copyright © 2009 John Wiley & Sons, Ltd. [source] Do nutrition labels improve dietary outcomes?,HEALTH ECONOMICS, Issue 6 2008Jayachandran N. Variyam Abstract The disclosure of nutritional characteristics of most packaged foods became mandatory in the United States with the implementation of the Nutrition Labeling and Education Act (NLEA) in 1994. Under the NLEA regulations, a ,Nutrition Facts' panel displays information on nutrients such as calories, total and saturated fats, cholesterol, and sodium in a standardized format. By providing nutrition information in a credible, distinctive, and easy-to-read format, the new label was expected to help consumers choose healthier, more nutritious diets. This paper examines whether the disclosure of nutrition information through the mandatory labels impacted consumer diets. Assessing the dietary effects of labeling is problematic due to the confounding of the label effect with unobserved label user characteristics. This self-selection problem is addressed by exploiting the fact that the NLEA exempts away-from-home foods from mandatory labeling. Difference-in-differences models that account for zero away-from-home intakes suggest that the labels increase fiber and iron intakes of label users compared with label nonusers. In comparison, a model that does not account for self-selection implies significant label effects for all but two of the 13 nutrients that are listed on the label. Published in 2007 by John Wiley & Sons, Ltd. [source] Use of instrumental variables in the presence of heterogeneity and self-selection: an application to treatments of breast cancer patientsHEALTH ECONOMICS, Issue 11 2007Anirban Basu Abstract Instrumental variable (IV) methods are widely used in the health economics literature to adjust for hidden selection biases in observational studies when estimating treatment effects. Less attention has been paid in the applied literature to the proper use of IVs if treatment effects are heterogeneous across subjects and individuals select treatments based on expected idiosyncratic gains or losses from treatments. In this paper we compare conventional IV analysis with alternative approaches that use IVs to estimate treatment effects in models with response heterogeneity and self-selection. Instead of interpreting IV estimates as the effect of treatment at an unknown margin of patients, we identify the marginal patients and we apply the method of local IVs to estimate the average treatment effect and the effect on the treated on 5-year direct costs of breast-conserving surgery and radiation therapy compared with mastectomy in breast cancer patients. We use a sample from the Outcomes and Preferences in Older Women, Nationwide Survey which is designed to be representative of all female Medicare beneficiaries (aged 67 or older) with newly diagnosed breast cancer between 1992 and 1994. Our results reveal some of the advantages and limitations of conventional and alternative IV methods in estimating mean treatment effect parameters. Copyright © 2007 John Wiley & Sons, Ltd. [source] A DYNAMIC ANALYSIS OF EDUCATIONAL ATTAINMENT, OCCUPATIONAL CHOICES, AND JOB SEARCH,INTERNATIONAL ECONOMIC REVIEW, Issue 1 2010Paul Sullivan This article examines career choices using a dynamic structural model that nests a job search model within a human capital model of occupational and educational choices. Wage growth occurs in the model because workers move between firms and occupations as they search for suitable job matches and because workers endogenously accumulate firm and occupation specific human capital. Simulations performed using the estimated model reveal that both self-selection in occupational choices and mobility between firms account for a much larger share of total earnings and utility than the combined effects of firm and occupation specific human capital. [source] Nonlinear taxation and punishmentINTERNATIONAL JOURNAL OF ECONOMIC THEORY, Issue 1 2007Tommy Andersson D82; H21 The paper analyzes nonlinear tax schedules that are identified by maximizing a welfare function represented by a weighted summation of net utilities over a set of n , 3 differing individuals. It is demonstrated that some of the feasible and Pareto efficient tax schedules that satisfy self-selection can only be identified by maximizing a welfare function of the above form if (at least) one of the individuals in the economy is assigned a negative weight. [source] Bias from Farmer Self-Selection in Genetically Modified Crop Productivity Estimates: Evidence from Indian DataJOURNAL OF AGRICULTURAL ECONOMICS, Issue 1 2007Benjamin Crost Q12; D81 Abstract In the continuing debate over the impact of genetically modified (GM) crops on farmers of developing countries, it is important to accurately measure magnitudes such as farm-level yield gains from GM crop adoption. Yet most farm-level studies in the literature do not control for farmer self-selection, a potentially important source of bias in such estimates. We use farm-level panel data from Indian cotton farmers to investigate the yield effect of GM insect-resistant cotton. We explicitly take into account the fact that the choice of crop variety is an endogenous variable which might lead to bias from self-selection. A production function is estimated using a fixed-effects model to control for selection bias. Our results show that efficient farmers adopt Bacillus thuringiensis (Bt) cotton at a higher rate than their less efficient peers. This suggests that cross-sectional estimates of the yield effect of Bt cotton, which do not control for self-selection effects, are likely to be biased upwards. However, after controlling for selection bias, we still find that there is a significant positive yield effect from adoption of Bt cotton that more than offsets the additional cost of Bt seed. [source] Do Local Landscape Patterns Affect the Demand for Landscape Amenities Protection?JOURNAL OF AGRICULTURAL ECONOMICS, Issue 1 2003Felix Schläpfer Agricultural support is increasingly flowing into the maintenance and improvement of landscape quality. While variations in the demand for landscape protection have been successfully attributed to variations in socio-economic characteristics, the effect of the local landscape setting as a potential determinant of environmental preferences has received less attention. A framework is formulated that describes public support for regional landscape protection as a function of socio-economic variables and land use patterns. Models are then estimated using detailed local land use statistics and voting records from a referendum on increasing public funding for local landscape amenities protection in the Swiss canton of Zurich. The land use variables represent proportions of open landscape and landscape features that are viewed as particularly valuable for aesthetic and other reasons. Cross-sectional estimation results suggest that attitudes towards public landscape protection are indeed strongly associated with the local landscape. Approval for protection programmes increased with local scarcity of open space and with the presence of high-amenity landscape features. Comparison with referendum outcomes on a national-level environmental issue suggests that the positive association with high-amenity landscape features may be partly attributable to individuals' self-selection of residency. [source] Importance of insect prey quality for grey partridge chicks Perdix perdix: a self-selection experimentJOURNAL OF APPLIED ECOLOGY, Issue 4 2000Claus Borg Summary 1.,The proportion of aphids in the cereal arthropod fauna has increased since the introduction of herbicides in the 1950s. In order to examine whether this increase has negative consequences for partridge chicks, a controlled experiment was carried out. Four groups of partridge chicks were fed different diets of fixed mixtures of grasshoppers and aphids, with aphid contents ranging from 0% to 45% wet weight. One additional group was allowed to select how much to eat of aphids and grasshoppers (self-selection). 2.,Over the run of the 5-day experiment the self-selecting chicks ate 7% wet weight of aphids and showed a higher growth rate than all groups on fixed diets. 3.,Increasing the proportion of aphids in the chick diet above the self-selected level had negative consequences for chick growth and flight feather development. 4.,Food consumption and growth efficiency were markedly lower when chicks were fed a diet with a high proportion of aphids. 5.,It is concluded that high densities of aphids cannot substitute for a diverse insect fauna as food for partridge chicks. Changes in the composition of the cereal arthropod fauna towards aphids constituting a greater proportion of available chick food may be detrimental to chick survival. [source] Enhancing well-being and alleviating depressive symptoms with positive psychology interventions: a practice-friendly meta-analysis,JOURNAL OF CLINICAL PSYCHOLOGY, Issue 5 2009Nancy L. Sin Abstract Do positive psychology interventions,that is, treatment methods or intentional activities aimed at cultivating positive feelings, positive behaviors, or positive cognitions,enhance well-being and ameliorate depressive symptoms? A meta-analysis of 51 such interventions with 4,266 individuals was conducted to address this question and to provide practical guidance to clinicians. The results revealed that positive psychology interventions do indeed significantly enhance well-being (mean r=.29) and decrease depressive symptoms (mean r=.31). In addition, several factors were found to impact the effectiveness of positive psychology interventions, including the depression status, self-selection, and age of participants, as well as the format and duration of the interventions. Accordingly, clinicians should be encouraged to incorporate positive psychology techniques into their clinical work, particularly for treating clients who are depressed, relatively older, or highly motivated to improve. Our findings also suggest that clinicians would do well to deliver positive psychology interventions as individual (versus group) therapy and for relatively longer periods of time. © 2009 Wiley Periodicals, Inc. J Clin Psychol: In Session 65: 1,21, 2009. [source] The impact of migration on rural poverty and inequality: a case study in ChinaAGRICULTURAL ECONOMICS, Issue 2 2010Nong Zhu Migration; Poverty; Inequality; China Abstract Large numbers of agricultural labor moved from the countryside to cities after the economic reforms in China. Migration and remittances play an important role in transforming the structure of rural household income. This article examines the impact of rural-to-urban migration on rural poverty and inequality in a mountainous area of Hubei province using the data of a 2002 household survey. Since migration income is a potential substitute for farm income, we present counterfactual scenarios of what rural income, poverty, and inequality would have been in the absence of migration. Our results show that, by providing alternatives to households with lower marginal labor productivity in agriculture, migration leads to an increase in rural income. In contrast to many studies that suggest that the increasing share of nonfarm income in total income widens inequality, this article offers support for the hypothesis that migration tends to have egalitarian effects on rural income for three reasons: (1) migration is rational self-selection,farmers with higher expected return in agricultural activities and/or in local nonfarm activities choose to remain in the countryside while those with higher expected return in urban nonfarm sectors migrate; (2) households facing binding constraints of land supply are more likely to migrate; (3) poorer households benefit disproportionately from migration. [source] Can Nutritional Label Use Influence Body Weight Outcomes?KYKLOS INTERNATIONAL REVIEW OF SOCIAL SCIENCES, Issue 4 2009Andreas C. Drichoutis SUMMARY Many countries around the world have already mandated, or plan to mandate, the presence of nutrition related information on most pre-packaged food products. Health advocates and lobbyists would like to see similar laws mandating nutrition information in the restaurant and fast-food market as well. In fact, New York City has already taken a step forward and now requires all chain restaurants with 15 or more establishments anywhere in US to show calorie information on their menus and menu board. The benefits were estimated to be as much as 150,000 fewer obese New Yorkers over the next five years. The implied benefits of the presence of nutrition information are that consumers will be able to observe such information and then make informed (and hopefully healthier) food choices. In this study, we use the latest available dataset from the US National Health and Nutrition Examination Survey (2005,2006) to explore whether reading such nutrition information really has an effect on body weight outcomes. In order to deal with the inherent problem of cross-sectional datasets, namely self-selection, and the possible occurrence of reverse causality we use a propensity score matching approach to estimate causal treatment effects. We conducted a series of tests related to variable choice of the propensity score specification, quality of matching indicators, robustness checks, and sensitivity to unobserved heterogeneity, using Rosenbaum bounds to validate our propensity score exercise. Our results generally suggest that reading nutrition information does not affect body mass index. The implications of our findings are also discussed. [source] From Welfare to Work: Evaluating a Tax and Benefit Reform Targeted at Single Mothers in SwedenLABOUR, Issue 3 2007Lennart Flood We formulate and estimate simultaneously a structural static model of labor supply and welfare participation. The results suggest that labor supply among single mother households in Sweden is quite elastic, and that there is self-selection into welfare. We also find that the proposed reform would generate welfare gains for virtually everyone in the sample, benefit low-income households, and would at the same time generate a small revenue surplus. [source] On-the-job leisure as a cause of asymmetric observed-effort distributionsMANAGERIAL AND DECISION ECONOMICS, Issue 6 2006David L. DickinsonArticle first published online: 18 SEP 200 When employers observe imperfect measures of worker effort, theorists typically assume that observed effort is unimodal and symmetrically distributed. Though observable effort may be distributed in different ways within a work day, for example, available field data on these effort distributions are rare. The symmetry assumption is largely untestable as a result. This paper presents empirical data from two experimental work environments that question the validity of such assumptions. For these piece-rate work environments the author finds that observed effort is significantly negatively-skew (i.e. modal>mean effort). The author's hypothesis is that on-the-job leisure causes this skewness in observed effort distributions. There are both theoretical and practical implications of this asymmetry. Some implications from the theoretical agency literature that we discuss include: self-selection into rank-order tournaments, optimal wage spreads in rank-order tournaments, and optimal wage contracts with asymmetric information. Copyright © 2006 John Wiley & Sons, Ltd. [source] Inverse association between farm animal contact and respiratory allergies in adulthood: protection, underreporting or selection?ALLERGY, Issue 4 2006K. Radon Background:, It has been argued that the inverse association between exposure to farm animals and nasal allergies observed in children and adults might be because of self-selection. Aims:, We aimed to assess the health-based selection out of farming in adults. Material and methods:, A cross-sectional study was carried out in a rural region. Overall, 4053 inhabitants (63%) aged 18,44 years responded to a questionnaire on respiratory diseases, life-time exposure to farming environments and potential confounders. For 2678 of these, specific immunoglobulin E to common allergens was available. The outcome was: (i) sensitization and symptoms of nasal allergies (symptomatic sensitization); (ii) sensitization without symptoms of nasal allergies (asymptomatic sensitization). Results:, Farm animal contact in childhood was associated with a decreased risk of symptomatic and asymptomatic sensitization. Continued exposure to farm animals in adulthood further decreased the odds ratio of symptomatic (odds ratio 0.2; 95% confidence interval 0.1, 0.4) but not asymptomatic sensitization (0.7; 0.4, 1.1). Starting farm animal contact in adulthood even increased the odds ratio of asymptomatic sensitization (2.4; 1.1, 5.2). Conclusions:, The preventive effect of childhood contact to farm animals against sensitization continues into adulthood. However, in adulthood self-selection based on symptoms and underreporting of symptoms might also play a role. [source] Temporary Help Agencies and Occupational Mobility,OXFORD BULLETIN OF ECONOMICS & STATISTICS, Issue 2 2005J. Ignacio García-Pérez Abstract This paper analyses the effects of Temporary Help Agencies (THA) on occupational mobility by performing an empirical comparison of the job-to-job upgrading chances of agency and regular (non-agency) workers in Spain. We estimate a switching regression model to allow for self-selection into agency work because of, for instance, more motivated workers being more likely to search for jobs through a THA. We find evidence in favour of the existence of self-selection in all qualification groups considered. Concerning mobility, we find that agency workers in intermediate qualification levels are less likely to experience demotions than regular workers. THA increase the probability of high-skilled workers achieving a permanent contract in Spain. [source] THE BIG FIVE PERSONALITY CHARACTERISTICS AS PREDICTORS OF EXPATRIATE'S DESIRE TO TERMINATE THE ASSIGNMENT AND SUPERVISOR-RATED PERFORMANCEPERSONNEL PSYCHOLOGY, Issue 1 2000PAULA M. CALIGIURI Applying the evolutionary theory of personality, this study proposed and tested the hypotheses that each of the Big Five personality characteristics (Extroversion, Agreeableness, Conscientiousness, Emotional Stability, and Openness or Intellect) predict two criteria of expatriate success: (a) desire to prematurely terminate the expatriate assignment, and (b) supervisor-rated performance on the expatriate assignment. The participants were 143 expatriate employees (and 94 supervisors) from a U.S.-based information technology company. Results from correlation and regression analyses suggest that Extroversion, Agreeableness, and Emotional Stability are negatively related to whether expatriates desire to terminate their assignment. Conscientiousness is positively related to the supervisor-rated performance on the expatriate assignment. Practical implications for expatriate management (e.g., self-selection) are given. [source] Discriminating tastes: self-selection of macronutrients in two populations of grasshoppersPHYSIOLOGICAL ENTOMOLOGY, Issue 3 2008DENNIS J. FIELDING Abstract The capacity to self-select an optimal balance of macronutrients (protein and carbohydrate) is studied in two populations of Melanoplus sanguinipes F. (Orthoptera: Acrididae). One population derives from the subarctic (interior of Alaska) and the other from the temperate zone (Idaho, U.S.A.). Over the duration of the fourth and fifth stadia, Alaskan grasshoppers consistently self-select a diet centred on a 0.90 ratio of protein : carbohydrate, whereas protein and carbohydrate intake by the Idaho grasshoppers is contingent on the particular food choices presented to them. When restricted to imbalanced diets, the Alaskan grasshoppers develop more rapidly than the Idaho grasshoppers, regardless of diet composition. The Idaho grasshoppers also have a greater amount of lipid than the Alaskan grasshoppers across all diets. Performance measures (body mass, survival, developmental times) are more sensitive to dietary imbalances in the Alaskan grasshoppers than in the Idaho grasshoppers. When fed diets with low, but balanced, proportions of protein and carbohydrate, grasshoppers of both populations are able to increase consumption to compensate for the low concentration of nutrients. The results suggest that demographic responses of insects to changes in host plant quality, such as may result from climate change, may differ among populations within a species. [source] Ergonomic risk factors for low back pain in North Carolina crab pot and gill net commercial fishermenAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 4 2009Kristen L. Kucera PhD Abstract Background The objective of this research was to determine the association between LBP that limited or interrupted fishing work and ergonomic low back stress measured by (1) self-reported task and (2) two ergonomic assessment methods of low back stress. Methods Eligible participants were from a cohort of North Carolina commercial fishermen followed for LBP in regular clinic visits from 1999 to 2001 (n,=,177). Work history, including crab pot and gill net fishing task frequency, was evaluated in a telephone questionnaire (n,=,105). Ergonomic exposures were measured in previous study of 25 fishermen using two methods. The occurrence rate of LBP that limited or interrupted fishing work since last visit (severe LBP) was evaluated in a generalized Poisson regression model. Results Predictors of severe LBP included fishing with crew members and a previous history of severe LBP. Among crab pot and gill net fishermen (n,=,89), running pullers or net reels, sorting catch, and unloading catch were associated with an increased rate of LBP. Percent of time in forces >20 lb while in non-neutral trunk posture, spine compression >3,400 N, and National Institute of Occupational Safety and Health lifting indices >3.0 were associated with LBP. Conclusions Tasks characterized by higher (unloading boat and sorting catch) and lower (running puller or net reel) ergonomic low back stress were associated with the occurrence of severe LBP. History of LBP, addition of crew members, and self-selection out of tasks were likely important contributors to the patterns of low back stress and outcomes we observed. Based on the results of this study, a participatory ergonomic intervention study is currently being conducted to develop tools and equipment to decrease low back stress in commercial crab pot fishing. Am. J. Ind. Med. 52:311,321, 2009. © 2009 Wiley-Liss, Inc. [source] EXPORTING AND PRODUCTIVITY: A FIRM-LEVEL ANALYSIS OF THE TAIWAN ELECTRONICS INDUSTRYTHE DEVELOPING ECONOMIES, Issue 3 2003Chih-Hai YANG Based on the panel data of Taiwanese electronics firms, this paper explores the relationship between exporting and productivity. Contemporaneous levels of exports and productivity are indeed positively correlated. The causality tests show causality from productivity to exporting and vice versa, implying that self-selection and learning-by-exporting effects coexist in the Taiwan electronics industry, while the learning-by-exporting effect is less supported. Exporting also has a positive impact on the productivity growth of firms, while the effect diminishes gradually after entering foreign markets. Decomposing the productivity growth shows that the reallocation effect accounts for only 20 per cent compared to the own-effect share of 80 per cent, which is mostly contributed by firms that continually export. [source] | ||||||||||||||||||||||||||||||||||||||||