2,412 research outputs found
The Utilization of U.S. male labor, 1975-1992: Estimates of foregone work hours
The percentage of working-age men in the United States who were fully active in the labor market decreased over the 1975-1992 period ("fully active" means working 2080 hours in a year). Similarly, the extent to which men were less than fully active increased. When one considers the number of hours by which men fell short of the 2080 norm in 1992, it was as if 20 percent of them did not work at all in that year, up from 18 percent in 1975. However, because the least-productive workers were the ones most likely to be less than fully active and the most-productive were the ones least likely to be less than fully active, total productivity-weighted work hours did not fall by this large an amount. If men failed to work 2080 hours in a year, most likely it was because they did not work at all; men most often did not work at all because they could find no jobs. Data were from Current Population Surveys.
Recent trends in U.S. male work and wage patterns: An overview
This paper brings together figures on recent trends in the labor market activity and wages of working-age men in the United States over the 1967-1992 period. The data, which come from Current Population Surveys, reveal several important developments. Year-long joblessness, the percentage of men failing to participate in the labor force, and the proportion who were unemployed rose throughout the period. Part-time employment as a percentage of all forms of employment was also higher at the end of the period than at the beginning, and the average hours worked by full-time workers increased slightly. Finally, median and mean wages fell. None of the trends was due to changes in the racial, educational, and age composition of the male work force; in fact, if the racial/educational/age composition had remained the same over the period, labor market activity would have declined even further.
Slipping anchor? Testing the vignettes approach to identification and correction of reporting heterogeneity
Anchoring vignettes are increasingly used to identify and correct heterogeneity in the reporting of health, work disability, life satisfaction, political efficacy, etc. with the aim of improving interpersonal comparability of subjective indicators of these constructs. The method relies on two assumptions: vignette equivalence – the vignette description is perceived by all to correspond to the same state; and, response consistency - individuals use the same response scales to rate the vignettes and their own situation. We propose tests of these assumptions. For vignette equivalence, we test a necessary condition of no systematic variation with observed characteristics in the perceived difference in states corresponding to any two vignettes. To test response consistency we rely on the assumption that objective indicators fully capture the covariation between the construct of interest and observed individual characteristics, and so offer an alternative way to identify response scales, which can then be compared with those identified from the vignettes. We also introduce a weaker test that is valid under a less stringent assumption. We apply these tests to cognitive functioning and mobility related health problems using data from the English Longitudinal Survey of Ageing. Response consistency is rejected for both health domains according to the first test, but the weaker test does not reject for cognitive functioning. The necessary condition for vignette equivalence is rejected for both health domains. These results cast some doubt on the validity of the vignettes approach, at least as applied to these health domains
Slipping anchor? Testing the vignettes approach to identification and correction of reporting heterogeneity
Elimination of TFA-Mediated Cleavage in Distributed Drug Discovery
Distributed Drug Discovery (D3) is a multi-disciplinary approach to the discovery of new drugs, which target neglected diseases or conditions common to developing-world countries. As part of a continuing effort to improve D3 methodology, two approaches for eliminating the final step TFA-mediated resin cleavage are proposed for investigation. Cleavage under basic conditions (saponification) and mild acid conditions (dilute HCl/hexafluoroisopropanol or dilute HCl/trifluoroethanol) represent improvements in safety and convenience to the undergraduate student researcher. Previous studies have shown that saponification provides yields comparable to the traditional TFA cleavage but recovery is not as convenient. Further improvements in the saponification workup will be evaluated by analyzing the effectiveness of simple trituration with acetone compared to use of a strong anion-exchange resin or drying reagents to isolate the free acid from the salt. Different trituration procedural modifications have been made and are being tested. Results have shown that in the presence of methanol, esterification will occur when the acid is liberated from the salt using HCl. To counter this problem, the samples are first evaporated to remove methanol and then the pH is adjusted with HCl. It was shown that using acetic acid did not result in pH levels low enough to guarantee complete protonation of the carboxylate. Through the use of a Bill-Board, an apparatus that holds six reaction vessels, several procedural modifications can be carried out simultaneously. Analysis is conducted by liquid chromatography coupled with a mass spectrometer and with nuclear magnetic resonance spectroscopy. Further studies will be carried out to assess the efficiency and practicality of using mild acidic conditions for cleavage using HCl/hexafluoroisopropanol or dilute HCl/trifluoroethanol. Both saponification and mild acid cleavage would represent improvements in safety and convenience to the undergraduate student researcher
Dissociation of CH₃–O as a Driving Force for Methoxyacetophenone Adsorption on Si(001)
The coverage-dependent behavior of p-methoxyacetophenone on the clean Si(001) surface was followed using X-ray photoelectron spectroscopy and supporting density functional theory calculations. Unlike other multifunctional organic molecules, this compound exhibits a high selectivity of adsorbate species formation by forming only two distinct adsorbate structures at low coverage, with a third configuration forming at high coverages. At low coverage, surface chemisorption is driven by methoxy group dissociation. However, at high coverage, the surface footprint required for this process is no longer available, leading to the formation of less thermodynamically stable adsorbates that are datively bonded to the surface with a smaller footprint. This coverage-dependent but well-defined behavior is promising in designing functional organic–inorganic interfaces on silicon
Adsorption and Dissociation of a Bicyclic Tertiary Diamine, Triethylenediamine, on a Si(100)-2 x 1 Surface
This study investigates the adsorption and thermal transformations of a bicyclic tertiary amine, triethylenediamine, on the clean Si(100)-2 × 1 surface. Below room temperature, triethylenediamine adsorption leads to the formation of a strong dative bond between one of the nitrogen atoms of this compound and the silicon surface. In contrast to previously studied amines, the datively adsorbed triethylenediamine features a second tertiary amine entity that is not bonded to the surface, with a lone pair orbital that is directed away from the surface and is available for further reactions. The thermal chemistry and electronic properties of triethylenediamine on silicon are studied using thermal desorption spectroscopy, infrared spectroscopy, and X-ray photoelectron spectroscopy. Near-edge X-ray absorption fine structure measurements are utilized to clarify the geometry of the adsorbates at room temperature. Density functional theory calculations are used to describe the binding geometry and electronic properties of the resulting surface species and the likely reaction paths at elevated temperatures
Relationship of Proteinases and Proteinase Inhibitors with Microbial Presence in Chronic Lung Disease of Prematurity
Background: A proteolytic imbalance has been implicated in the development of “classical” chronic lung disease of prematurity (CLD). However, in “new” CLD this pattern has changed. This study examines the longitudinal relationship between neutrophil proteinases and their inhibitors in ventilated preterm infants and their relationship to microbial colonisation. Methods: Serial bronchoalveolar lavage fluid was obtained from ventilated newborn preterm infants. Neutrophil elastase (NE) activity, cell counts, metalloproteinase (MMP)-9, MMP-9/TIMP-1 complex, SerpinB1 concentration and percentage of SerpinB1 and α1-antitrypsin (AAT) in complex with elastase were measured. The presence of microbial genes was examined using PCR for 16S rRNA genes. Results: Statistically more infants who developed CLD had NE activity in at least one sample (10/20) compared with infants with resolved respiratory distress syndrome (RDS) (2/17). However, NE activity was present in a minority of samples, occurring as episodic peaks. Peak levels of MMP-9, MMP-9/TIMP-1 complex, percentage of AAT and SerpinB1 in complex and cell counts were all statistically greater in infants developing CLD than in infants with resolved RDS. Peak values frequently occurred as episodic spikes and strong temporal relationships were noted between all markers. The peak values for all variables were significantly correlated to each other. The presence of bacterial 16S rRNA genes was associated with the development of CLD and with elevated elastase and MMP-9. Conclusion: NE activity and MMP-9 appear to be important in the development of “new” CLD with both proteinase and inhibitor concentrations increasing episodically, possibly in response to postnatal infection
Phospholipid signaling in innate immune cells
Phospholipids comprise a large body of lipids that define cells and organelles by
forming membrane structures. Importantly, their complex metabolism represents a
highly controlled cellular signaling network that is essential for mounting an effective
innate immune response. Phospholipids in innate cells are subject to dynamic
regulation by enzymes, whose activities are highly responsive to activation status.
Along with their metabolic products, they regulate multiple aspects of innate immune
cell biology, including shape change, aggregation, blood clotting, and degranulation.
Phospholipid hydrolysis provides substrates for cell-cell communication, enables
regulation of hemostasis, immunity, thrombosis, and vascular inflammation, and is
centrally important in cardiovascular disease and associated co-morbidities.
Phospholipids themselves are also recognized by innate-like T cells, which are
considered essential for recognition of infection or cancer, as well as self-antigens. This
review will describe the major phospholipid metabolic pathways present in innate
immune cells and summarize the formation and metabolism of phospholipids as well as
their emerging roles in cell biology and disease
How do we get people into contact? Predictors of intergroup contact and drivers of contact seeking
Compared to the impressive amount of research on consequences of intergroup contact, relatively little work has been devoted to predictors of intergroup contact. Although opportunities for intergroup contact are constantly growing in modern diverse societies, these contact opportunities are not necessarily exploited. In the present review article, we describe current research on predictors of intergroup contact and drivers of contact seeking on a micro‐, meso‐, and macro‐level. We provide an overview of predictors, while focusing on recent research that is especially relevant for designing interventions and planning social policies aiming at increasing contact between different groups in varied societies. On the micro‐level, we discuss relational self‐expansion motives and confidence in contact as predictors of intergroup contact. On the meso‐level, we focus on the role of intragroup processes and historical intergroup conflicts in facilitating contact. On the macro‐level, we reflect on changing societal norms as a potential tool to increase the frequency intergroup contact. By focusing on the applied value of research findings, discussing diverse predictors, and applying a multilevel approach, we also address recent criticisms of the intergroup contact literature and demonstrate the generative nature of contemporary research in this area
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