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11.
12.
J. Matthew Shumway 《Papers in Regional Science》1993,72(2):159-176
The length of time that individuals are unemployed has considerable political and policy significance. Important questions about the factors influencing the duration of unemployment remain to be answered. The purpose of this paper is to carry out an empirical investigation of the factors that cause unemployment to be of a longer or shorter duration. Such factors are identified within a micro-economic framework drawn from human capital and job search theories. Event history methods and panel data are used to model unemployment duration. The data come from the Survey of Income and Program Participation (SIPP) which contains weekly information on labor force status over about a two and a half year period, as well as data on a number of individual and locational attributes. Evidence from the empirical investigation suggests that migration, temporary layoff and income during unemployment combine with individual characteristics to influence the duration of unemployment spells.An earlier version of this paper was presented at the 38th North American Meetings of the RSAI, New Orleans, LA, November 1991. 相似文献
13.
Matthew Chamberlain 《电子设计技术》2006,13(1):96
平板液晶技术的迅猛发展让大屏幕、宽视角、高质量的视频图像得以实现。但是,随着液晶电视的屏幕变大、亮度更高,工作时所需的电压和电流也逐渐增加。而且,由于液晶电视屏幕中配置了多种供用户使用的接口,所以特别容易由于过电流和过电压的原因而出现损坏。 相似文献
14.
Over the last century, IQ scores have been steadily rising, a phenomenon dubbed the Flynn effect. Because of the Flynn effect, IQ tests are periodically renormed, making them harder. Given that eligibility for mental retardation (MR) services relies heavily on IQ scores, renormed tests could have a significant impact on MR placements. In longitudinal IQ records from 9 sites around the country, students in the borderline and mild MR range lost an average of 5.6 points when retested on a renormed test and were more likely to be classified MR compared with peers retested on the same test. The magnitude of the effect is large and affects national policies on education, social security, the death penalty, and the military. This paper reports the perceptions of professionals as they relate to IQ score fluctuations in normal, borderline, and/or MR populations. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
15.
Studied the differences in moral orientation in terms of gender specific modes of reasoning, in 2 experiments. In Exp 1, 32 Ss (aged 24–55 yrs) were read the "Heinz dilemma," and asked 3 questions regarding it. Deliberative and justificatory strategies were identified on the basis of the presence or absence of the higher level knowledge structures. In Exp 2, 40 undergraduates were presented with "Michael and Kohlberg Heinz dilemma," followed by a set of relevant questions. Male Ss preferred to apply a norm or rule in their solutions, while females rejected the application of a norm and sought alternative solutions. This was replicated in Exp 2, but the pattern was reversed with female Ss preferring to apply a norm. Males were divided in their use of either strategy indicating that although, genders differed in their judgments as to which norms or rules to apply; once adopted, norms and rules were used in similar ways. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
16.
Nick Fourikis Kimberley W. Eccleston Nick Lioutas Matthew J. Sorell 《Journal of Infrared, Millimeter and Terahertz Waves》1991,12(7):819-843
Scalar network analysers measuring the amplitude of the reflection/transmission coefficients of waveguide structures have been realised at Ka- and W-bands. Their accuracy derived by using standard mismatches is excellent at Ka- band and fairly good at W-band. To our knowledge this is the first instance where the accuracy of measurements obtained from a scalar network analyser was checked over full waveguide bands with the aid of standard mismatches. The reported reflectometers are precursors of vector network analysers based on six-port reflectometers. Methods aimed at increasing the signal-to-noise ratio (SNR) of the measurements have been developed, while proposals for improving the dynamic range of these network analysers are put forward. 相似文献
17.
Ahluwalia Jasjit S.; Nollen Nicole; Kaur Harsohena; James Aimee S.; Mayo Matthew S.; Resnicow Ken 《Canadian Metallurgical Quarterly》2007,26(2):214
Objectives: Examine the effectiveness of an intervention to increase fruits and vegetables (FV) consumption among smokers. Design: Cluster-randomized trial of 20 public housing developments; 10 randomly assigned to an FV intervention and 10 to a smoking cessation intervention. Main outcome measures: Usual (past 7 days) and past 30 days change in daily FV intake at 8 weeks and 6 months postbaseline. Results: Greater increases were seen in the FV group. At Week 8 and Month 6, the FV group had consumed 1.58 (p = .001) and 0.78 (p = .04), respectively, more daily FV servings in the past 7 days than the cessation group. At the same time points, the FV group had consumed 3.61 (p = .01) and 3.93 (p = .01), respectively, more FV servings in the past 30 days than the cessation group. Completing more motivational interviewing sessions (p = .02) and trying more recipes (p = .02) led to significantly greater increases at Month 6 among FV participants. Conclusions: Motivational interviewing counseling and lifestyle modification through trying out healthy recipes may be effective in helping a high-risk population increase their FV intake. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
18.
Matthew John M. Krane Frank P. Incropera 《Metallurgical and Materials Transactions A》1995,26(9):2329-2339
Numerical calculations based on a continuum model are used to examine the effects of solidification shrinkage on the redistribution
of solute in a Pb-19.2 pct Sn mixture which is convectively cooled at a sidewall. For each of three different cooling rates,
separate calculations are performed for shrinkage and buoyancy-induced flows, as well as for the combined influence of shrinkage
and buoyancy effects. The calculations reveal that flow and macrosegregation patterns are more strongly influenced by buoyancy
effects over a wide range of solidification rates. Although extremely large solidification rates yield small regions near
the chilled wall in which shrinkage-induced flows control the redis-tribution of solute, the overall effect on macrosegregation
is small relative to that associated with buoyancy. Scaling analysis of the governing equations produces reference shrinkage
and buoyancy velocities which can be used to extend the current numerical results to other binary systems. 相似文献
19.
Zhufang Liu Mohammad Shamsuzzoha Earl T. Ada W. Matthew Reichert David E. Nikles 《Journal of power sources》2007
Well-dispersed Pt nanoparticles with controlled size and narrow size distribution were prepared by polyalcohol reduction of platinum acetylacetonate, using oleylamine as a capping agent. The particle size was varied from 3.5 nm to 11.5 nm by decreasing the amount of oleylamine added in the synthesis. Size selection of the as-prepared particles by solvent fractionation yielded nearly monodispersed Pt particles. The as-prepared particles were loaded on a carbon support by physical deposition, but showed no electrocatalytic activity due to the oleylamine bound to the particle surface. The particles were activated for electrocatalysis after heating the particles in air at 185 °C for 5 h, conditions that gave no particle-sintering and no oxidation. Cyclic voltammetry showed that the particles after the heat treatment in air were electrocatalytically active for methanol oxidation. The smaller 3.5 nm and 4.0 nm Pt particles had a higher intrinsic activity for methanol oxidation, but a lower tolerance to CO poisoning, compared with 6.0 nm, 9.5 nm and 11.5 nm particles. CO-stripping results suggest that CO is more easily oxidized on larger Pt particles. 相似文献
20.
Tabletability of five types of maltodextrin, a filler/binder excipient, was studied by testing their loading potentials with acetaminophen. The formulations consisted of excipient and acetaminophen at five different ratios and magnesium stearate at a 0.5% concentration. These mixtures were compacted employing an Integrated Compaction Research System at a constant punch velocity of 100 mm/sec. under varying applied pressures from 50 to 450 MPa. Compaction data were evaluated using the total work of compaction vs applied pressure plots whilst the post-compaction tests included the measurements of crushing force, disintegration time, and friability of the resulting tablets. Both the energy involved during the compaction of a formulation and the crushing force values of the resulting tablets decreased as the amount of the maltodextrin in a formulation was reduced. Maltodextrins exhibited adequate binding potential at acetaminophen drug loading levels of only up to twenty-five percent. The disintegration times of the tablets containing maltodextrins were generally prolonged and this was found to be due to the formation of a “gel” layer around the tablet which formed on immersion into water. The tabletability of maltodextrins were also compared to that of Fast-Flo lactose, and the compactability of these excipients were found to be similar. 相似文献