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.

A hardware library for sensors/actuators interfaces in sensor networks

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. J. Portilla, J. L. Buron, T. Riesgo, and A. de Castro, "A hardware library for sensors/actuators interfaces in sensor networks", and 13th IEEE International Conference on Electronics, Circuits and Systems, ICECS 2006, Nice (France), 2006, pp. 1244 - 1247.Sensor networks have reached a great relevance during the last years. The idea is to use a high number of nodes measuring different physical parameters in several environments, which implies different research challenges (low power consumption, communication protocols, platform hardware design, etc). There is a tendency to use modular hardware nodes in order to make easier rapid prototyping as well as to be able to redesign faster and reuse part of the hardware modules. One of the main obstacles for rapid prototyping is that sensors present heterogeneous interfaces. In this paper, a VHDL library for sensors/actuators interfaces is proposed in order to have a set of different sensor interfaces that include the most common in the sensors/actuators world, enabling a rapid connection to a new sensor/actuator

Comparaison microstructurale et mécanique de polypropylènes-choc recyclés : suivi de l'endommagement et du vieillissement

International audienceCette étude porte sur des polypropylènes (PP)-chocs provenant du recyclage de pare-chocs de véhicules hors d'usage. Deux voies sont étudiées pour l'utilisation du matériau recyclé : soit en mélange avec du matériau neuf, soit après un traitement spécifique (TR) visant à éliminer la peinture. Des différences microstructurales ont été identifiées par DSC et DMA entre les différents PP-chocs étudiés. Ces matériaux soumis à des essais de traction s'endommagent par cavitation ; cet endommagement a été suivi et quantifié à différents stades de déformation à partir des mesures de variation de volume. Le matériau résultant du mélange présente une meilleure ductilité et un endommagement très légèrement retardé par rapport au matériau recyclé seul. Le traitement TR semble plus prometteur au niveau du comportement mécanique car il conduit à des matériaux encore plus ductiles et présentant un endommagement nettement retardé. Par ailleurs, le vieillissement thermique à 80°C de ces matériaux n'entraîne pas, après six à dix-huit mois de suivi, de variation significative au niveau des caractéristiques mécaniques et de l'endommagement, ce qui témoigne d'une très bonne stabilité de ces PP-chocs recyclés

Transient vitamin B5 starving improves mammalian cell homeostasis and protein production.

Maintaining a metabolic steady state is essential for an organism's fitness and survival when confronted with environmental stress, and metabolic imbalance can be reversed by exposing the organism to fasting. Here, we attempted to apply this physiological principle to mammalian cell cultures to improve cellular fitness and consequently their ability to express recombinant proteins. We showed that transient vitamin B5 deprivation, an essential cofactor of central cellular metabolism, can quickly and irreversibly affect mammalian cell growth and division. A selection method was designed that relies on mammalian cell dependence on vitamin B5 for energy production, using the co-expression of the B5 transporter SLC5A6 and a gene of interest. We demonstrated that vitamin B5 selection persistently activates peroxisome proliferator-activated receptors (PPAR), a family of transcription factors involved in energy homeostasis, thereby altering lipid metabolism, improving cell fitness and therapeutic protein production. Thus, stable PPAR activation may constitute a cellular memory of past deprivation state, providing increased resistance to further potential fasting events. In other words, our results imply that cultured cells, once exposed to metabolic starvation, may display an improved metabolic fitness as compared to non-exposed cells, allowing increased resistance to cellular stress

Variabilidad en la brotación de las yemas vegetativas de los olmos europeos

The bud-burst dates of clones of Ulmus minor, Ulmus glabra, and Ulmus laevis were recorded in the field during the spring of 2000, 2001 and 2002 at six locations in five European countries. Meteorological data were obtained from stations close to the plots. Thermal time to bud-burst (T) and chilling (C) were calculated. A relationship on the form T = a + b erC was fitted for each species. In the three species, winter rest release seems to be controlled by two opposite quantitative effects of the temperature, which interrelate according to an inverse exponential relation. Besides, the bud-burst date was found to be stable between years characterised by different winter thermal trends. These three Elm species have small chilling requirements. U. minor has chilling requirements lower than those of the other two species, in agreement with the more southern distribution.Durante las primaveras de los años 2000, 2001 y 2002 se registró en campo, en seis localidades de cinco países europeos, la fecha de apertura de yemas en un número de clones pertenecientes a Ulmus minor, Ulmus glabra y Ulmus laevis. Simultáneamente se obtuvieron datos meteorológicos en estaciones próximas a las parcelas. Se calculó los grados día (T) y el requerimiento de frío (C). Para cada especie se estableció una relación de la forma T = a + b erC. En las tres especies, la interrupción de la quiescencia parece estar controlada por dos efectos termales cuantitativos opuestos, relacionados por una exponencial inversa. Se ha encontrados que la fecha de apertura de yemas ha sido estable incluso en años con características térmicas invernales considerablemente diferentes. Los requerimientos de frío son pequeños en las tres especies de olmo. U. minor requiere fríos menores que las otras dos especies, lo que es consistente con su distribución más meridional