Implications of skill-biased technological change: international evidence

Demand for less skilled workers decreased dramatically in the US and in other developed countries over the past two decades. WE argue that pervasive skill-biased technological change, rather than increased trade with the development world, is the principal culprit. The pervasiveness of this technological change is important for two reasons. Firstly, it is an immediate and testable implication of technological change. Secondly, under standard assumptions, the more pervasive the skill-biased technological, the greater the increase in the embodied supply of less skilled workers and the greater the increase in the embodied supply if less skilled workers and the greater the increases in the embodied supply of less skilled workers and the greater the depressing effect on their relative wages through world goods prices. In contrast, in the Heckscher-Ohlin model with small open economies the skill-bias of local technological changes does not affect wages. Thus, pervasiveness deals with a major criticism of skill-biased technological as a cause. Testing the implications of pervasive, skill-biased technological change, we find strong supporting evidence. Firstly, across the OECD, most industries have increased the proportion of skilled workers employed, despite rising or stable relative wages. Secondly, increases in demand for skills were concentrated in the same manufacturing industries in different developed countries

The Impact of Dormancy Breakers on Hormone Profiles, Fruit Growth and Quality in Sweet Cherry

Chemical dormancy breakers are often used to manipulate floral bud break in sweet cherry production, and their use is increasing due to unpredictable climate effects. The role of plant hormones in regulating the critical transition of floral buds from dormant to opening in deciduous trees is now emerging. By monitoring changes in endogenous hormone levels within floral buds that are undergoing the transition from dormant to the growing state in response to various cues (environmental and/or chemical inducers), we can begin to distinguish the plant hormones that are the drivers of this process. This study sought to identify key hormonal regulators of floral bud break using sweet cherry as a model and modifying timing of bud break through the application of two chemical dormancy breakers, hydrogen cyanamide (HC, Dormex®) and emulsified vegetable oil compound (EVOC, Waiken®), and to determine the effect of these chemicals on fruit growth and quality. Treatments were applied at label rates 35–40 days before estimated bud break. We found that HC-treated tree buds broke earlier, and this was associated with a significant early elevation of the cytokinins dihydrozeatin and dihydrozeatin riboside compared to the control and EVOC-treated tree buds. In contrast, changes in auxin and abscisic acid content did not appear to explain the hastened bud burst induced by hydrogen cyanamide. While HC-treated trees resulted in larger fruit, there was a higher incidence of cracked fruit and the pack-out of A-grade fruit was reduced. The increase in fruit size was attributed to the earlier flowering and hence longer growing period. Harvest assessment of fruit quality showed no treatment effect on most quality parameters, including fruit dry matter content, total soluble solids or malic acid content, but a reduction in fruit compression firmness and stem pull force in EVOC-treated trees was observed. However, all fruit still met the Australian industry fruit quality export market standards. This study offers important insights into bud hormonal activities underpinning the action of these chemical regulators; understanding bud responses is critically important to ensuring consistent and sustainable fruit tree production systems into the future. It also demonstrates that the dormancy-breaking agents HC and EVOC have no detrimental impact on fruit quality at harvest or following storage, however growers need to be aware of the potential for increased fruit cracking when earlier bud break results in a longer growing season which has the potential to increase fruit size. Further studies are required to determine the role of gibberellin in hastening bud break by dormancy breaker

Relationships of the early insulin secretory response and oral disposition index with gastric emptying in subjects with normal glucose tolerance

The oral disposition index, the product of the early insulin secretory response during an oral glucose tolerance test and insulin sensitivity, is used widely for both the prediction of, and evaluation of the response to interventions, in type 2 diabetes. Gastric emptying, which determines small intestinal exposure of nutrients, modulates postprandial glycemia. The aim of this study was to determine whether the insulin secretory response and the disposition index (DI) related to gastric emptying in subjects with normal glucose tolerance. Thirty-nine subjects consumed a 350 mL drink containing 75 g glucose labeled with 99mTc-sulfur colloid. Gastric emptying (by scintigraphy), blood glucose (G) and plasma insulin (I) were measured between t = 0-120 min. The rate of gastric emptying was derived from the time taken for 50% emptying (T50) and expressed as kcal/min. The early insulin secretory response was estimated by the ratio of the change in insulin (∆I0-30) to that of glucose at 30 min (∆G0-30) represented as ∆I0-30/∆G0-30 Insulin sensitivity was estimated as 1/fasting insulin and the DI was then calculated as ∆I0-30/∆G0-30 × 1/fasting insulin. There was a direct relationship between ∆G0-30 and gastric emptying (r = 0.47, P = 0.003). While there was no association of either ∆I0-30 (r = -0.16, P = 0.34) or fasting insulin (r = 0.21, P = 0.20), there were inverse relationships between the early insulin secretory response (r = -0.45, P = 0.004) and the DI (r = -0.33, P = 0.041), with gastric emptying. We conclude that gastric emptying is associated with both insulin secretion and the disposition index in subjects with normal glucose tolerance, such that when gastric emptying is relatively more rapid, both the early insulin secretory response and the disposition index are less. These findings should be interpreted as "hypothesis generating" and provide the rationale for longitudinal studies to examine the impact of baseline rate of gastric emptying on the prospective risk of type 2 diabetes.Chinmay S. Marathe, Christopher K. Rayner, Kylie Lange, Michelle Bound, Judith Wishart, Karen L. Jones, Steven E. Kahn and Michael Horowit

Quantum waveguides with a lateral semitransparent barrier: spectral and scattering properties

We consider a quantum particle in a waveguide which consists of an infinite straight Dirichlet strip divided by a thin semitransparent barrier on a line parallel to the walls which is modeled by a $\delta$ potential. We show that if the coupling strength of the latter is modified locally, i.e. it reaches the same asymptotic value in both directions along the line, there is always a bound state below the bottom of the essential spectrum provided the effective coupling function is attractive in the mean. The eigenvalues and eigenfunctions, as well as the scattering matrix for energies above the threshold, are found numerically by the mode-matching technique. In particular, we discuss the rate at which the ground-state energy emerges from the continuum and properties of the nodal lines. Finally, we investigate a system with a modified geometry: an infinite cylindrical surface threaded by a homogeneous magnetic field parallel to the cylinder axis. The motion on the cylinder is again constrained by a semitransparent barrier imposed on a ``seam'' parallel to the axis.Comment: a LaTeX source file with 12 figures (11 of them eps); to appear in J. Phys. A: Math. Gen. Figures 3, 5, 8, 9, 11 are given at 300 dpi; higher resolution originals are available from the author

Household Disposal of Pharmaceuticals as a Pathway for Aquatic Contamination in the United Kingdom

Pharmaceuticals are produced and used in increasingly large volumes every year. With this growth comes concern about the fate and effects of these compounds in the environment. The discovery of pharmaceuticals in the aquatic environment has stimulated research in the last decade. A wide range of pharmaceuticals has been found in fresh and marine waters, and it has recently been shown that even in small quantities, some of these compounds have the potential to cause harm to aquatic life. The primary pathway into the environment is the use and disposal of medicines; although much of the research in the area currently focuses on the removal of pharmaceuticals during sewage treatment processes, disposal via household waste might be a significant pathway requiring further research. To investigate the household disposal of unused and expired pharmaceuticals as a source of pharmaceutical compounds in the environment, we carried out a survey and interviewed members of 400 households, predominantly from southeastern England. We used the information on when and how they disposed of unfinished pharmaceuticals to construct a conceptual model to assess the pathways of human pharmaceuticals into the environment. The model demonstrated that disposal of unused pharmaceuticals, either by household waste or via the sink or toilet, may be a prominent route that requires greater attention

The Effect of Disability Insurance Receipt on Labor Supply: A Dynamic Analysis

This paper estimates the effect of Disability Insurance receipt on labor supply, accounting for the dynamic nature of the application process. Exploiting the effectively random assignment of judges to disability insurance cases, we use instrumental variables to address the fact that those allowed benefits are a selected sample. We find that benefit receipt reduces labor force participation by 26 percentage points three years after a disability determination decision when not considering the dynamic nature of the applications process. OLS estimates are similar to instrumental variables estimates. We also find that over 60% of those denied benefits by an Administrative Law Judge are subsequently allowed benefits within 10 years, showing that most applicants apply, re-apply, and appeal until they get benefits. Next, we estimate a dynamic programming model of optimal labor supply and appeals choices. Consistent with the law, we assume that people cannot work and appeal at the same time. We match labor supply, appeals, and subsequent allowance decisions predicted by the model to the decisions observed in the data. We use the model to predict labor supply responses to benefit denial when there is no option to appeal. We find that if there was no appeals option, those denied benefits are 35 percentage points more likely to work. However, there is considerable heterogeneity in responses. Most individuals in their 40s would return to work if denied benefits, for example. Our results suggest that many of those denied benefits not because they are unable to work, but because they remain out of the labor force in order to appeal their benefit denial

Pricing in Online Auction Procurement: A Review of Empirical Methods and Current Understandings

The online auction has become an important channel for procurement and sourcing management. As firms often expect lower procurement prices through online auctions, how the prices are determined in online auctions should be of major interest to procurement managers and supply chain researchers. Despite the abundant empirical studies on online auction prices, an aggregated view is still absent. This study fills this gap with a review of extant studies. More specifically, this study provides summaries of all major theories behind online auction pricing, defines and analyzes often encountered econometric issues, and discusses how the treatments of these issues have been operationalized. Towards the end, existing findings on determinants of online auction prices are integrated and examined. The purpose of this study is to provide a convenient and precise package of current studies for researchers and professional