The Effect of Labor Market Changes from the Early 1970s to the Late 1980s on Youth Wage, Earnings, and Household Economic Position

While overall employment in the United States has risen in the last 30 years, the employment and earnings prospects for youths have fallen relative to those for older workers. This deterioration in youth labor market conditions has been most pronounced for low-skilled youths, high school dropouts, and those with low IQs. Using data from national longitudinal studies of young men, young women, and youths, this paper examines a number of aspects of the labor market outcomes of youths entering the labor market at two different times. The first group entered the robust labor market of the late 1960s, while the second group entered the deteriorated labor market of the mid-1980s. Consistent with previous research, this paper finds an improvement over the two periods in levels of employment and earnings for high-skilled youths, with a corresponding deterioration for lower-skilled youths. The paper presents a unique analysis of the growth trajectories of earnings and employment for high- and low-skilled youths in the two cohorts. We find substantial within-cohort growth for high-skilled youths in both cohorts (as well an improvement in household economic circumstances), with a corresponding deterioration in earnings, employment, and household economic circumstances for lower-skilled youths, especially those in the later cohort.

The Nomenclatural Status of Saperda Inordata Say (Coleoptera: Cerambycidae)

Excerpt: Confusion as to the identity and proper name of our common Saperda on trembling aspen, Populus tremuloides Michaux, in eastern North America should be clarified. The confusion has arisen from three reasons: (1) LeConte failed to distinguish S. concolor Lec. (1852) from S. irornata Say (1824); (2) Say\u27s type material was destroyed or lost which makes verification impossible; and (3) S. inornata varies from light to dark in overall appearance. The former two points are discussed here and the latter will be covered in a separate article. Authors since LeConte\u27s time have used a variety of binominal and trinominal designations for this species. In 1924 J. 0. Martin suggested that the name inornata, which had been placed in the Genus Mecas, really belonged in the Genus Saperda and that S. inornata should be reinstated replacing LeConte\u27s concolor which Martin, followed by Breuning (1952), considered a synonym of inornata. Despite Martin\u27s suggestion, S. concolor is in common use today. However, a search of the literature produced evidence which substantiates Martin\u27s claim that inornata must stand (Nord, 1968). A summary of this search is presented here in detail and a neotype has been proposed so that the nomenclature will be stabilized (Nord and Knight, 1970)

The Geographic Variation of Saperda Inornata Say (Coleoptera: Cerambycidae) in Eastern North America

Excerpt: During the summers of 1962 and 1963 a study of the life history and behavior of what was thought to have been Saperda moesta LeConte in trembling aspen, Populus tremuloides Michaux, was completed in northern Michigan (Nord, 1968). After the field study, it became apparent that the original identification was doubtful. Furthermore, there was a possibility that two species were present in the study areas, thus the biological data collected may have represented not one but two species

The Distribution of Saperda Inornata and Oberea Schaumii (Coleoptera: Cerambycidae) within the Crowns of Large Trembling Aspens, Populus Tremuloides

The larvae of Saperda inornata Say and Oberea schaumii LeConte inhabit the stems of trembling aspen (Populus tremuloides Michaux) root suckers and the twigs of larger trees. Nord et al. (1972a, 1972b) reported the biologies of these species in Upper Michigan and northern Wisconsin. S. inornata has a one or two year life cycle, probably depending on how early the egg is laid. Most (77.5%) 0. schaumii develop in three years while 5.0% require only two years and 17.5% require four years to develop. Knight (1963) described the distribution of galleries made by S. inornata and 0. schaumii in the crowns of large trembling aspen, P. tremuloides, in Upper Michigan. Similar distribution data were gathered from 180 large trembling aspen felled in a survey designed to determine the relative abundance of S. inornata and 0. schaumii in stands of different site quality (Nord and Knight 1972b). The analysis of that distribution data and comparisons with that of Knight (1963) are presented here. Inter- and intra-specific competition in light of the results and other behavioral information are discussed

The Importance of Saperda Inornata and Oberea Schaumii (Coleoptera: Cerambycidae) Galleries as Infection Courts of Hypoxylon Pruinatum in Trembling Aspen, Populus Tremuloides

(excerpt) Trembling aspen, Populus tremuloides Michaux, and bigtooth aspen, P. grandidentata Michaux, are hosts of numerous species of injurious insects and microorganisms (Harrison 1959). Only a few of those organisms, however, are directly responsible for mortality of healthy trees. The fungus Hypoxylon pruinatum (Klotzsche) Cke. is most important in that respect, killing 1-2%o f the standing volume annually in the Lake States (Anderson 1964). It invades and spreads in cambial tissue, killing it and eventually the branch or stem by girdling. Initially, a canker appears as a sunken, yellowish-orange area in the bark (Anderson 1956). In a later stage the outer bark raises in blister-like patches and sloughs off exposing blackened, crumbling cortex

The Relationship of the Abundance of \u3ci\u3eSaperda Inornata\u3c/i\u3e and \u3ci\u3eOberea Schaumii\u3c/i\u3e (Coleoptera: Cerambycidae) in Large Trembling Aspen, \u3ci\u3ePopulus Tremuloides\u3c/i\u3e, to Site Quality

Saperda inornata Say and Oberea schaumii LeConte are cerambycids that inhabit the stems of trembling aspen, Populus tremuloides Michaux, root suckers and the twigs of larger trees. The biologies of those species in northern Wisconsin and Upper Michigan were reported by Nord et al. (1972a and 1972b). S. inornata oviposits on the cambium under horseshoe- or shield-shaped egg niches gnawed in the outer bark by the female. The term egg niche, connotes an oviposition place prepared by the female using the mandibles and ovipositor (Linsley 1959). There are usually 2 or 3 egg niches at one level on the stem or twig, and a globose gall consisting of callus tissue forms there. The larvae feed in the cambial and callus tissue around the gall and require 1 or 2 years to complete development. The 0. schaurnii female gnaws an elongate, rectangular egg niche in the outer bark and deposits an egg on the cambium beneath it. The larva bores downward from the egg niche in the wood. Most individuals require 3 years to complete the life cycle; but some take only 2 years, while others take 4 years. A survey designed to determine the importance of the egg niches and galleries of S. inornata and 0. schaumii as infection courts of Hypoxylon pruinatum (Klotzsche) Cke. in large trembling aspen was begun in 1962 in Iron and Ontonogan Counties, Michigan. The data from that survey indicated that abundance of borers might be correlated with the site quality of the stand. Therefore in 1963 the survey was redesigned to detect differences in abundance between stands of different site quality. Since the redesign concerned only the selection of stands, not the sampling procedures used within the stand, most of the trees sampled in 1962 were incorporated into the redesigned survey. The data collected in conjuction with the survey also make possible conclusions regarding the distribution of borer galleries within the crowns of large trees. Those results and a discussion of competition between S. inornata and 0. schaurnii are given in another paper (Nord and Knight, 1972a). The incidence of H. pruinatum in the galleries was reported by Nord and Knight (1972b)

The Hymenopterous Parasites Agathis Pumila (Braconidae) and Epilampsis Laricinellae (Eulophidae) on the Larch Casebearer (Lepidoptera: Coleophoridae) in the Northern Lake States

Excerpt: The larch casebearer Coleophora laricella (Hübner) is a defoliator of larch (Larix spp.). The insect was introduced into North America from Europe at some time prior to 1886, and since has spread steadily westward. It was causing heavy defoliation by the early 1920\u27s near Ann Arbor in southern Michigan and was recorded in northeast Wisconsin in 1939, at Sault Ste. Marie, Ontario in 1942, and Port Arthur, Ontario in 1947. Many native parasites attack the case bearer but seem to effect little control. Parasites were imported from Europe beginning in 1928, but the first attempts to establish them were unsuccessful. In 1932, the United States Bureau of Entomology and Plant Quarantine made releases of Agathis pumila (Ratz.) at Lynwood, Massachusetts, and Epilampsis laricinellae (Ratz.) in Lunenburg Township, Massachusetts. These two species were successfully established

Are searching and non-searching unemployment distinct states when unemployment is high? The case of South Africa

Broadly and narrowly measured unemployment rates differ very markedly in certain countries, and the measure chosen to be the ‘official’ unemployment rate affects perceptions about the extent of the problem. The appropriate measure of the unemployment rate depends on whether jobless persons who say they want work but who are not actively searching should be regarded as part of the labour force. This paper examines whether the non-searching-unemployed state is distinct from the searching-unemployed state in a developing country - South Africa - where the broad unemployment rate and the gap between the broad and narrow rates are both very high. It asks whether lack of job-search among jobless persons claiming to want work is an outcome of tastes or of constraints. It finds evidence in support of adopting the broad definition.

Sampling design for compliance monitoring of surface water quality: A case study in a Polder area

International agreements such as the EU Water Framework Directive (WFD) ask for efficient sampling methods for monitoring natural resources. In this paper a general methodology for designing efficient, statistically sound monitoring schemes is described. An important decision is the choice between a design-based and a model-based method, implying the choice between probability (random) sampling and purposive sampling. For mapping purposes, model-based methods are more appropriate, whereas to obtain valid results for the universe as a whole, such as in testing water quality standards against legal standards, we generally prefer a design-based method. Four basic sampling patterns in space-time universe are described: static, synchronous, static-synchronous, and rotational. A case study is carried out for monitoring the quality of surface water at two farms in western Netherlands, wherein a synchronous sampling design is applied, with stratified simple random sampling in both space and time. To reduce laboratory costs the aliquots taken at the locations of a given sampling round are bulked to form a composite. To test the spatiotemporal mean N-total concentration during the summer half-year against the MAR standard with a power of 80% at a concentration 15% below the MAR standard and with a confidence of 95%, six to nine sampling rounds are needed with 50 to 75 locations per sampling round. For P-total the required number of sampling rounds differs strongly between the two farms, but is for both farms much larger than for N-total

List Size, Standards and Perfromance in General Practice - A Pilot Study in the South East Thames Region

This is a report of a piolt study carried out among 155 general practitioner trainers in South East Thames region. Similar pilot studies have been carried out among trainers in four other regions on England. Separate reports have been prepared for each of the five regions, together with a summary report comparing the findings among the regions. The pilot studies were funded by the DHSS and carried out by staff of the Health Services Research Unit at the University of Kent at Camterbury