Solution of the Boussinesq equations by means of the finite element method

A finite element method is presented for the computation of flows that are influenced by buoyancy forces. The accuracy of several finite elements is studied by solving the Bénard problem and determining the critical Rayleigh number. It is found that the accuracy is greatly enhanced if the shape functions satisfy a certain requirement that arises from the physical nature of the problem

Why should governments intervene in education, and how effective is education policy

This paper reviews arguments for government interference in the education sector and discusses the effectiveness of commonly used policy instruments. There are both efficiency and equity reasons for government intervention. Particular attention is paid to education spillovers (an efficiency motive). The empirical literature shows that there is little reason to argue for additional policy efforts to correct for externalities. There is some promising evidence, however, for non-pecuniary spillovers in the form of crime reduction and health improvements. With regard to the effectiveness of policy instruments, the paper discusses studies with a (quasi-)experimental design so that the causal impact of the policy can be identified. Early childhood interventions appear to be more effective than interventions in later stages of the education cycle.

The Emergence of a European Community of Communication - Insights from Empirical Research on the Europeanization of Public Spheres

A European public sphere emerges out of Europeanized national public spheres if the following two phenomena are verified. First, if and when the same (European) themes are discussed at the same time with similar frames of reference, meaning structures, and patterns of interpretation across the various media sources. Second, if and when a transnational community of communication emerges in which speakers and listeners recognize each other as legitimate participants in a discourse that frames the issues at stake as common European problems. We present empirical evidence from other scholars and two case studies of our own, namely Eastern enlargement and the sanctions against the Austrian ÖVP/FPÖ-government. The main finding is that at least when European issues are discussed, that a European public sphere is constituted and re-constituted through the discursive connections and debates across borders.European Public Sphere; media; Europeanization; Europeanization

Chemical thinning of 'Conference' pears

The increasing difference in the market value of small and larger sized ‘Conference’ pears (>65 mm) and the high labour costs for hand thinning, makes it interesting for growers to find a cheaper and reliable method for thinning pear trees. In 2007, 2008 and 2009 trials were carried out to test the thinning efficacy of several chemicals. Fruit set was only significantly reduced by a two-fold application of ammonium thiosulphate (ATS) or by a tankmix application of 6-benzyladenine (BA) and 1-naphtalene acetic acid (NAA). Unfortunately, russeting of ‘Conference’ pears was augmented by the treatments with ATS during bloom. Tankmix applications of NAA + BA, applied at an average fruit diameter of 8.8 mm, resulted in a severe overthinning of the trees in 2008. However, the same treatments applied at an average fruit diameter of 14.7 mm had much less of a thinning effect. In 2009 adequate thinning was obtained with lower concentrations of BA+NAA applied at 8-10 mm fruit diameter. Surprisingly, the reduction in fruit set by BA+NAA did not result in a proptional increase in the average fruit weight at harvest. In some treatments average fruit weight was even reduced compared to that of the hand-thinned trees, a size-reducing effect that was attributed to NAA. In conclusion, BA+NAA seems to thin ‘Conference’ pears more strongly than BA alone. However, the addition of NAA to BA has the disadvantage of a diminishing effect on the increment of fruit size, i.e. fruit size increased less than expected on basis of the reduction in crop load. Additional research will be carried out to further optimise the developmental stage, weather conditions, and concentrations at which a BA and NAA must be applied to obtain the desired level of thinning and gain in yield percentage of fruits over 65 mm in diameter

Did the 2006 covenants reduce school dropout in the Netherlands?

Early school-leaving is considered to be one of the major problems in Dutch education. In order to reduce the number of dropouts in the school year 2006-2007 the Dutch government has offered a financial incentive scheme to 14 out of 39 regions. This scheme provides a reward of 2000 euro per school dropout less in 2006-07. The target of the scheme was a reduction of the total number of school dropouts by at least 10 percent in one year. This paper evaluates the effectiveness of this school dropout policy by comparing the change in school dropout in these 14 regions with the change in the remaining 25 regions before and after the introduction of the policy. We observe a modest decline in the probability of dropping out in the 14 covenants regions. However, the decline in the non-covenant regions was equally large. We therefore find no significant effect on the probability of dropping out in the post-covenant year. In both regions, the number of dropouts has fallen by 3 percent in the year after the covenants. This nationwide decline can be largely assigned to changes in the student populations among the pre- and post-covenant year. The covenants also gave a reward to regions for a successful reintegration of dropouts in order to reduce school dropout in that way. However, estimates for the effect on the re-enrolment of previous dropouts are statistically insignificant as well. We conclude that 2006 covenant policy has not been effective in reducing early school-leaving.

The effect of early tracking on participation in higher education

This paper examines the impact of early tracking on enrollment in and completion of higher education. We compare pupils that are directly tracked in lower general secondary education (ââ¬Ëmavoââ¬â¢) to pupils that postpone their choice of education level by entering secondary education in a combined first-grade class. Potential self-selection problems are addressed in two ways. First of all, using micro data allows us to control for a large set of individual background characteristics including tests of cognitive ability. Second, we exploit differences in regional supply of particular school types. The estimates show that early tracking has a detrimental effect on enrollment in and completion of higher education for pupils who leave primary education with a mavo advice. In addition, we find no evidence that pupils who leave primary education with a higher general secondary education (‘havo’) advice would be negatively affected by being in a comprehensive class together with the mavo advice pupils. Enrollment in and completion of higher education can be increased by stimulating participation in combined first-grade classes that keep pupils with a mavo or havo advice together for an additional one or two years.

Skill gaps in the EU: role for education and training policies

Skill gaps are widely seen as a problem that lowers aggregate productivity growth. A question for the European Commission is whether and how governments should take action with education and training policies to reduce skill gaps and make Europe the best performing region in the world. European citizens can best decide for themselves on the type of education. Distribution of information on occupation prospects is effective to influence their choice of education. Moreover, it is important that the education system is sufficiently flexible to absorb unexpected shocks in skill needs of employees. Policies stimulating education targeted at government-assigned sectors are risky policies. Intensification of general education at the cost of specific education, and intensification of training of employees find little support.