Return on investment in higher education : evidence for different subjects, degrees and gender in Germany

Applying an investment perspective to higher education, the paper presents detailed empirical evidence on the rate of return to higher education and its determinants. Employing a sample of 17,180 higher education graduates derived from the German Labor Force Survey 2004, we show considerable variation in the rates of return to higher education across the different subjects, with some subjects on average not representing attractive private investments from an economic point of view. We find that the decision what to study is worth several hundred thousand Euros. Applying regression analysis, we find gender- and degree-specific return advantages only in certain subjects. Comparing the return of an investment in higher education and the production cost of higher education, we show that more expensive subjects (apart from Medicine) yield a lower return. When considering the cost of study, the overall order of attractiveness of the different forms of education remains stable, but the investment in further subjects is no longer clearly attractive. Keywords: Returns to Education, Human Capital, Higher Education Earnings Capacity

Desirable properties for XML update mechanisms

The adoption of XML as the default data interchange format and the standardisation of the XPath and XQuery languages has resulted in significant research in the development and implementation of XML databases capable of processing queries efficiently. The ever-increasing deployment of XML in industry and the real-world requirement to support efficient updates to XML documents has more recently prompted research in dynamic XML labelling schemes. In this paper, we provide an overview of the recent research in dynamic XML labelling schemes. Our motivation is to define a set of properties that represent a more holistic dynamic labelling scheme and present our findings through an evaluation matrix for most of the existing schemes that provide update functionality

When Order matters for Iterated Strict Dominance

We demonstrate that iterated elimination of strictly dominated strategies is an order dependent procedure. We also prove that order does not matter if strategy spaces are compact and payoff functions continous. Examples show that this result is tight.game theory; iterated strict dominance; order independence

Alternative Compensation Arrangements and Productive Efficiency in Partnerships: Evidence from Medical Group Practice

Although the role of the services sector in the economy has grown increasingly large, and partnerships are a prevalent form of organization in this sector, relatively little is known about the behavior and performance of these firms. In this paper an attempt is made to fill that gap by developing and testing a model of the effect of alternative compensation arrangements on productive efficiency in medical group practices. The technique employed is two-stage production frontier estimation. This technique provides direct estimates of productive efficiency and allows for differences across agents in ability or responsiveness to financial incentives. In the frontier literature productive efficiency is assumed to be exogenously given. In this paper it is determined endogenously, thus a simple econometric technique correcting for this endogeneity in estimating the production frontier is employed. In addition, the measures of efficiency themselves can be made dependent variables for explicit econometric analysis of the determinants of efficiency. Overall, the empirical results are consistent with theoretical work on internal theory of the firm, which predicts that productivity compensation schemes will work well for firms with non-joint production and observable output. These two criteria are met by medical group practices. The treatment of measured efficiency as an endogenous variable is unique and allows some interesting insights into the determinants of productive efficiency. We find that relating compensation to productivity does increase the quantity and efficiency of production, as theory has hypothesized. The number of members in a group decreases both the quantity produced and the efficiency with which that output is produced. Experience does lead to greater productivity and efficiency. Medical groups in general are measured as being no less efficient than an average manufacturing firm, but Health Maintenance Organizations are less efficient than average.

Decidability Results for the Boundedness Problem

We prove decidability of the boundedness problem for monadic least fixed-point recursion based on positive monadic second-order (MSO) formulae over trees. Given an MSO-formula phi(X,x) that is positive in X, it is decidable whether the fixed-point recursion based on phi is spurious over the class of all trees in the sense that there is some uniform finite bound for the number of iterations phi takes to reach its least fixed point, uniformly across all trees. We also identify the exact complexity of this problem. The proof uses automata-theoretic techniques. This key result extends, by means of model-theoretic interpretations, to show decidability of the boundedness problem for MSO and guarded second-order logic (GSO) over the classes of structures of fixed finite tree-width. Further model-theoretic transfer arguments allow us to derive major known decidability results for boundedness for fragments of first-order logic as well as new ones

Hyperon masses in nuclear matter

We analyze hyperon and nucleon mass shifts in nuclear matter using chiral perturbation theory. Expressions for the mass shifts that include strong interaction effects at leading order in the density are derived. Corrections to our results are suppressed by powers of the Fermi momentum divided by either the chiral symmetry breaking scale or the nucleon mass. Our work is relevant for neutron stars and for large hypernuclei

A Modeling Experiment on the Grounding of an Ice Shelf in the Central Arctic Ocean During MIS 6

High-resolution chirp sonar subbottom profiles from the Lomonosov Ridge in the central Arctic Ocean, acquired from the Swedish icebreaker Oden in 1996, revealed large-scale erosion of the ridge crest down to depths of 1000 m below present sea level [Jakobsson, 1999]. Subsequent acoustic mapping during the SCICEX nuclear submarine expedition in 1999 showed glacial fluting at the deepest eroded areas and subparallel ice scours from 950 m water depth to the shallowest parts of the ridge crest [Polyak et al., 2001]. The directions of the mapped glaciogenic bed-forms and the redeposition of eroded material on the Amerasian side of the ridge indicate ice flow from the Barents-Kara Sea area. Core studies revealed that sediment drape the eroded areas from Marine Isotope Stage (MIS) 5.5 and, thus, it was proposed that the major erosional event took place during Marine Isotope Stage (MIS) 6 [Jakobsson et al., 2001]. Glacial geological evidence suggests strongly that the Late Saalian (MIS 6) ice sheet margin reached the shelf break of the Barents-Kara Sea [Svendsen et al. in press] and this gives us two possible ways to explain the ice erosional features on the Lomonosov Ridge. One is the grounding of a floating ice shelf and the other is the scouring from large deep tabular iceberg. Here we apply numerical ice sheet modeling to test the hypothesis that an ice shelf emanating from the Barents/Kara seas grounded across part of the Lomonsov Ridge and caused the extensive erosion down to a depth of around 1000 m below present sea level. A series of model experiments was undertaken in which the ice shelf mass balance (surface accumulation and basal melting) and ice shelf strain rates were adjusted. Grounding of the Lomonosov Ridge was not achieved when the ice shelf strain rate was 0.005 yr-1 (i.e. a free flowing ice shelf). However this model produced two interesting findings. First, with basal melt rates of up to 50 cm yr-1 an ice shelf grew from the St. Anna Trough ice stream across the section of the ridge where there is evidence for grounding. Second, even with ultra low rates of basal melting, the ice shelf thickness was always less than 200 m over the ridge. We conclude that grounding of the Lomonosov Ridge by a free-flowing ice shelf is not possible. When the strain rate was reduced to zero, however, the shelf thickness increased substantially. Such conditions are likely only to have occurred during periods of large-scale glaciation across the Eurasian Arctic such as in the Saalian, and if a substantial stagnant thickened sea ice was present in the ocean, buttressing the shelf flowing from the Barents Sea. Our results are interpreted using new techniques for dynamic 3Dvisualization