Spatial interpolation of high-frequency monitoring data

Climate modelers generally require meteorological information on regular grids, but monitoring stations are, in practice, sited irregularly. Thus, there is a need to produce public data records that interpolate available data to a high density grid, which can then be used to generate meteorological maps at a broad range of spatial and temporal scales. In addition to point predictions, quantifications of uncertainty are also needed. One way to accomplish this is to provide multiple simulations of the relevant meteorological quantities conditional on the observed data taking into account the various uncertainties in predicting a space-time process at locations with no monitoring data. Using a high-quality dataset of minute-by-minute measurements of atmospheric pressure in north-central Oklahoma, this work describes a statistical approach to carrying out these conditional simulations. Based on observations at 11 stations, conditional simulations were produced at two other sites with monitoring stations. The resulting point predictions are very accurate and the multiple simulations produce well-calibrated prediction uncertainties for temporal changes in atmospheric pressure but are substantially overconservative for the uncertainties in the predictions of (undifferenced) pressure.Comment: Published in at http://dx.doi.org/10.1214/08-AOAS208 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Quantification of depth of anesthesia by nonlinear time series analysis of brain electrical activity

We investigate several quantifiers of the electroencephalogram (EEG) signal with respect to their ability to indicate depth of anesthesia. For 17 patients anesthetized with Sevoflurane, three established measures (two spectral and one based on the bispectrum), as well as a phase space based nonlinear correlation index were computed from consecutive EEG epochs. In absence of an independent way to determine anesthesia depth, the standard was derived from measured blood plasma concentrations of the anesthetic via a pharmacokinetic/pharmacodynamic model for the estimated effective brain concentration of Sevoflurane. In most patients, the highest correlation is observed for the nonlinear correlation index D*. In contrast to spectral measures, D* is found to decrease monotonically with increasing (estimated) depth of anesthesia, even when a "burst-suppression" pattern occurs in the EEG. The findings show the potential for applications of concepts derived from the theory of nonlinear dynamics, even if little can be assumed about the process under investigation.Comment: 7 pages, 5 figure

A Preliminary Analysis of SACMEQ III South Africa

The many and varied links between student socio-economic status and educational outcomes have been well documented in the South African economics of education literature. The strong legacy of apartheid and the consequent correlation between education and wealth have meant that, generally speaking, poorer students perform worse academically. The present study uses the recent Southern and East African Consortium for Monitoring Educational Quality (SACMEQ III) dataset for South Africa to identify those factors that have a significant effect on student maths and reading performance in Grade 6. The research confirms previous findings that socio-economic status, and particularly school socioeconomic status, is important when understanding student success or failure. Other factors which contribute significantly to student performance are homework frequency, preschool education, and the availability of reading textbooks. In contrast, teacher-subject knowledge was found to have only a modest impact on Grade 6 student performance. Policy interventions are also highlighted. The study concludes that South Africa is still a tale of two schools: one which is wealthy, functional and able to educate students, while the other is poor, dysfunctional, and unable to equip students with the necessary numeracy and literacy skills they should be acquiring in primary school. Nevertheless, it suggests that there are some options available to policy-makers which are expected to have a positive effect on student performance.SACMEQ, South Africa, primary education, education, education production function, education policy, economics of education

How High Performance Human Resource Practices and Workforce Unionization Affect Managerial Pay

Using data from a nationally representative sample of telecommunications establishments, this study finds that HR practices and workforce unionization influence managerial pay levels and the ratio of manager-to-worker pay. High performance HR practices, including investment in the skills of the workforce, in computer-based technologies, and in performance-based worker pay practices, are all positively related to managerial pay; but the use of workforce teams, which shift some managerial responsibilities to workers, has the opposite association. High performance HR practices also are associated with lower manager to- worker pay differentials. In addition, workforce unionization is positively associated with managerial pay levels, with worker base pay mediating the relationship between managers\u27 pay and unionization

Performance Persistence of Dutch Pension Funds

This paper studies the investment performance of pension funds with a focus on their ability in implementing their intended investment strategy. We use a sample of Dutch industry-wide pension funds, which are obliged by law to report their investment performance according to the so-called z-score. The z-score is a risk-adjusted performance measure with benchmark settings predefined by Dutch law. We find that pension funds as a group cannot beat their self-selected benchmarks consistently. Applying a cross-sectional portfolio approach we find evidence that the largest pension funds outperform the smallest funds

How Country and Safety-Net Characteristics Affect Bank Risk-Shifting

Risk-shifting occurs when creditors or guarantors are exposed to loss without receiving adequate compensation. This project seeks to measure and compare how well authorities in 56 countries controlled bank risk shifting during the 1990s. Although significant risk shifting occurs on average, substantial variation exists in the effectiveness of risk control across countries. We find that the tendency for explicit deposit insurance to exacerbate risk shifting is tempered by incorporating loss-control features such as risk-sensitive premiums, coverage limits, and coinsurance. Introducing explicit deposit insurance has had adverse effects in environments that are low in political and economic freedom and high in corruption.

Efficiency and distribution in contract farming:The case of Indian poultry growers

This paper is an empirical analysis of the gains from contract farming in the case of poultry production in the state of Andhra Pradesh in India. The paper finds that contract production is more efficient than noncontract production. The efficiency surplus is largely appropriated by the processor. Despite this, contract growers still gain appreciably from contracting in terms of lower risk and higher expected returns. Improved technology and production practices as well as the way in which the processor selects growers is what makes these outcomes possible. In terms of observed and unobserved characteristics, contract growers have relatively poor prospects as independent growers. With contract production, these growers achieve incomes comparable to that of independent growersContract Farming, Contracting, Poultry, Vertical Integration

A comparison of A-level performance in economics and business studies: how much more difficult is economics?

This paper uses ALIS data to compare academic performance in two subjects often viewed as relatively close substitutes for one another at A-level. The important role of GCSE achievement is confirmed for both subjects. There is evidence of strong gender effects and variation in outcomes across Examination Boards. A counterfactual exercise suggests that if the sample of Business Studies candidates had studied Economics nearly 40% of those who obtained a grade C or better in the former subject would not have done so in the latter. The opposite exercise uggests that 12% more Economics candidates would have achieved a grade C or better if they had taken Business Studies. In order to render a Business Studies A-level grade comparable to an Economics one in terms of relative difficulty, we estimate that a downward adjustment of 1.5 UCAS points should be applied to the former subject. This adjustment is lower than that suggested by correction factors based on conventional subject pair analysis for these two subjects

Inequality, Well-being and Institutions in Latin America and the Caribbean

This paper focuses on the role of “institutions” in the fight against poverty and inequality. Our view of institutions encompasses formal rules designed by polity (including those in the legal and economics sphere such as rules of property rights, contracts and liabilities) as well as informal rules (usually labelled social capital) that have emerged over the history of one’s civilisation. The inclusion of health, nutrition, and literacy indicators in defining well-being (or, non-income poverty à la capability approach of Amartya Sen) allows a rich discussion of policy interventions. While both orientations as to the concepts of poverty, inequality and institutions are expounded on a priori reasoning, empirical analysis with LAC data prove rewarding. Quality of institutions (measured by a composite variable called institutional capital, IC) turns out to be a key factor explaining well-being. Further where the level of income is also important to the explanation, the quantitative role of the institutional factor dominates that of the income variable. Within IC, political stability (or lack of violence) appeared to provide the more precise estimates in every case. Consequently we argue that the foremost policy interventions ought to be in the areas of building both adequate formal institutions, as well as creating an enabling environment for the informal institutions (such as social capital) to flourish and find their own roots. The principal focus of the policy debate must centre on the mutual interaction of market as well as non-market institutions in reducing poverty broadly speaking

External financing of US corporations: Are loans and securities complements or substitutes?

“Multiple avenues of intermediation” (Greenspan 2000) suggest substitutability of corporate loan and bond finance which smooths external financing flows. Holmstrom and Tirole (1997) stress complementarity; for most firms bank finance and consequent monitoring is essential for bond finance. Econometric work based on their model is consistent with complementarity both on average over time and during financial crises, and for levels and volatilities. It implies that “multiple avenues” may not be effective as a buffer in a bank credit crunch, and hence supply-side blockages of bank credit may impact on real activity. There are important implications for regulation, not least Basel II