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.

secCl is a cys-loop ion channel necessary for the chloride conductance that mediates hormone-induced fluid secretion in Drosophila

Organisms use circulating diuretic hormones to control water balance (osmolarity), thereby avoiding dehydration and managing excretion of waste products. The hormones act through G-protein-coupled receptors to activate second messenger systems that in turn control the permeability of secretory epithelia to ions like chloride. In insects, the chloride channel mediating the effects of diuretic hormones was unknown. Surprisingly, we find a pentameric, cys-loop chloride channel, a type of channel normally associated with neurotransmission, mediating hormone-induced transepithelial chloride conductance. This discovery is important because: 1) it describes an unexpected role for pentameric receptors in the membrane permeability of secretory epithelial cells, and 2) it suggests that neurotransmitter-gated ion channels may have evolved from channels involved in secretion

Assessing the impact of autonomous motivation and psychological need satisfaction in explaining adherence to an exercise referral scheme

Given the mixed findings concerning self-determination theory in explaining adherence to exercise referral schemes (ERS), the present study attempted to examine whether autonomous motivation and psychological need satisfaction could predict ERS adherence. Participants referred to an 8-week ERS completed self-report measures grounded in self-determination theory and basic needs theory at baseline (N = 124), mid-scheme (N = 58), and at the end of the scheme (N = 40). Logistic regressions were used to analyse the data. Autonomous motivation measured at mid-scheme explained between 12 and 16% of the variance in ERS adherence. Autonomy, relatedness and competence measured at mid-scheme explained between 18 and 26% of the variance in ERS adherence. This model also explained between 18 and 25% when measured at the end of the scheme. The study found limited evidence for the role of autonomous motivation in explaining ERS adherence. Stronger support was found for the satisfaction of the three needs for autonomy, relatedness and competence in predicting ERS adherence. Future research should tap into the satisfaction of all three needs collectively to help foster ERS adherence

Photoluminescence of near-lattice-matched GaN/AlInN quantum wells grown on free-standing GaN and on sapphire substrates

Near-lattice-matched GaN/Al1−xInxN single quantum wells, grown using both free-standing GaN and conventional GaN-on-sapphire substrates, are studied by photoluminescence (PL) and PL excitation spectroscopies. PL spectra distinguish luminescence originating in the wells, barriers, and underlying GaN buffer layers. The spectra also reveal significant differences between structures grown simultaneously on the different substrates. The quantum well transition energy decreases as the well width increases due to the intense in-built electric fields, estimated to be 3.0±0.5 MeV/cm, that persist in strain free GaN/Al1−xInxN. Screening of these fields is studied using the excitation power dependence of the P

Reflectance - Current state of research and future directions for archaeological charcoal; Results from a pilot study on Irish Bronze Age cremation charcoals

‘Reflectance’ is a method that estimates the absolute burn temperature of charcoal from the ‘shininess’ of resin mounted samples. The method's usefulness for archaeological charcoal is yet to be comprehensively studied. This article details first results from reflectance testing of archaeological charcoals excavated from Irish Bronze Age cremations, which included calcined bone. As calcination of bone commences at 650 °C, it was expected that the charcoals would reflect at least this temperature. This was not the case for taxonomically identified charcoals >2 mm, nor for micro-charcoals of c. 250 μm, although measured temperatures rose slightly with decreasing fraction size of charcoal remains. Depositional practice, combustion completeness and taphonomic influences may have all played a part in this result, and these will need careful consideration in different archaeological circumstances. However, the greatest challenge for reflectance of archaeological materials lies in obtaining full agreement on the production and use of reflectance calibration curves. Current calibration curves differ substantially, by 100–150 °C (±50–75 °C) and in one instance up to as much as 180 °C (±90 °C). Without better agreement on calibration, the method's ultimate usefulness in archaeological research will be limited. At the level of refinement currently possible, it will still be useful for determining very high or very low temperature processes, and possibly the difference between charcoal fuel and raw wood fuel fires. The latter has distinct implications for estimating ancient forest wood consumption, since more wood is consumed in processes employing charcoal fuel. Proving the utility of reflectance for archaeological purposes may also require modification of normal practice for archaeological field collection of charcoal, to include collection and laboratory processing of un-sieved soil samples.The authors acknowledge the support of the CSIRO, Sydney; the Department of Archaeology, and the Australian Centre for Microscopy and Microanalysis, University of Sydney (especially materials preparation specialist, Mr Adam Sikorski); and the McDonald Institute for Archaeological Research, University of Cambridge. Excavations were carried out by Margaret Gowen & Co. Ltd, funded by the National Roads Authority, Ireland. This research was partly funded by the Government of Ireland, Irish Research Council (Project id GOIPD/2013/387) supported by the School of Archaeology, University College Dublin

The nest as fortress: defensive behavior of Polybia emaciata, a mud-nesting eusocial wasp

The swarm-founding wasp Polybia emaciata is unusual among eusocial Vespidae because it uses mud, rather than wood pulp, as its primary nest construction material. Polybia emaciata nests are more durable than similarly sized paper nests. We tested the hypothesis that the defensive behavior of this wasp may have been modified to take advantage of their strong nests in defense against vertebrate attacks. We simulated vertebrate disturbances by tapping on, and breathing in, P. emaciata nests and similarly sized P. occidentalis paper nests in the same location at the same time. Polybia emaciata responses to disturbance were qualitatively different from those of P. occidentalis. The latter exit the nest and attack, while P. emaciata workers typically fled or entered the nest, attacking only after repeated and extended disturbances. We conclude that durable nest material may permit predator avoidance behavior in P. emaciata. We compare the defensive responses of P. emaciata workers with those of other swarm-founding Vespidae, and discuss several selective forces that could cause the evolution of species variation in nest defense behavior

Using the PUMA System

This document describes the operation of the Lisp Machine interface to the Unimation Puma 600 Robot Arm. The interface is evolved from a system described in an earlier paper, and much is the same. However, the under-lying interface between the Lisp Machine and the Puma has changed and some enhancements have been made. VAL has been replaced with a PDP-11/23, communicating with the Lisp Machine over the Chaosnet. The purpose of this document is to provide instruction and information in the programming of the Puma arm from the Lisp Machine. The network protocol is not described here, nor are the internals of the implementation. These details are provided in separate documentation. The reader will find in this paper both a tutorial section and a reference section. The tutorial will lead the reader through a sample session using the Puma by directly calling the primitive operations, and will provide an introduction to programming using the primitives. The reference section provides an overview of the network protocol and describes all of the primitive operations provided. Please note that this document corresponds to the version of the Puma system in use on 11 March, 1985. The system is still undergoing development and enhancement, and there may be additional features, if you are running a newer system. The authors welcome reports of errors, inaccuracies, or suggestions for clarification or improvement in either the documentation or the code for the Puma system. Please send electronic mail to [email protected] Artificial Intelligence Laborator

Puma/Cougar Implementor's Guide

This document is intended to be a guide to assist a programmer in modifying or extending the Lisp Puma system, the Puma PDP-11 system, or the Cougar PDP-11 system. It consists mostly of short descriptions or hints, and is not intended to be a polished manual. The reader is expected to be familiar with the use of the Puma system, as described in "Using the PUMA System," and the Lisp flavor system, as described in the Lisp Machine Manual.MIT Artificial Intelligence Laborator