A semi-Lagrangian scheme for the game pp-Laplacian via pp-averaging

We present and analyze an approximation scheme for the two-dimensional game $p$-Laplacian in the framework of viscosity solutions. The approximation is based on a semi-Lagrangian scheme which exploits the idea of $p$-averages. We study the properties of the scheme and prove that it converges, in particular cases, to the viscosity solution of the game $p$-Laplacian. We also present a numerical implementation of the scheme for different values of $p$; the numerical tests show that the scheme is accurate.Comment: 34 pages, 3 figures. To appear on Applied Numerical Mathematic

The BIOEXPLOIT Project

The EU Framework 6 Integrated Project BIOEXPLOIT concerns the exploitation of natural plant biodiversity for the pesticide-free production of food. It focuses on the pathogens Phytophthora infestans, Septoria tritici, Blumeria graminis, Puccinia spp. and Fusarium spp. and on the crops wheat, barley, tomato and potato. The project commenced in October 2005, comprises 45 laboratories in 12 countries, and is carried out by partners from research institutes, universities, private companies and small-medium enterprises. The project has four strategic objectives covered in eight sub-projects. These objectives relate to (i) understanding the molecular components involved in durable disease resistance, (ii) exploring and exploiting the natural biodiversity in disease resistance, (iii) accelerating the introduction of marker-assisted breeding and genetic engineering in the EU plant breeding industry, and (iv) coordinating and integrating resistance breeding research, providing training in new technologies, disseminating the results, and transferring knowledge and technologies to the industry

The conversion of aneurin into aneurinpryrophosphate by blood corpuscles

1. The in vitro synthesis of aneurinpyrophosphate from added aneurin by the white and red cells of the blood of the rat and of man was studied. Though the synthesis is by no means negligible in human blood it is much higher in rat blood. 2. An average rat leukocyte contains about 160 times as much aneuripyrophosphate as an average rat erythrocyte. This ratio is increased to about 550 upon incubation of the blood with 1 mg aneurin per ml. 3. The synthesis in inhibited by oxalate, monoiodoacetate, fluoride and cyanide. 4. The synthesis by the red cells is preferentially inhibited by oxalate, the synthesis by the white cells by cyanide. This proves that the energy required for the synthesis of aneurinpyrophosphate from aneurin is mainly provided by glycolysis in the red cells and by respiration in the white cells. 5. Upon incubation of the blood with a small amount of aneurin a higher percentage is converted into aneurinpyrophosphate than with a large amount of aneurin. However, even from 0.1 gamma-aneurin added to 1 ml of blood only 26% is phosphorylated (from 1 mg added about 0.25% is phosphorylated). 6. During incubation of rat blood with aneurin at 39°C aneurin is not destroyed, nor are substances formed inhibiting aneurin pyrophosphate synthesis. 7. The synthesis of aneurinpyrophosphate by the erythrocytes depends upon the concentration of glucose present. It is decreased when the glucose concentration is below normal or extremely high. 8. The enzym system responsible for the synthesis of aneurinpyrophosphate from aneurin is badly damaged by incubating the blood at 39°C for some hours. 9. Attention is called to the fact that process producing energy are necessary for the conversion of a certain vitamin into its physiologically active form. As other vitamins form part of various enzymes connected with energy production insight into the interrelationship of various avitaminoses may be gained from investigations on the influence of the lack or one vitamin in the food on the conversion of another vitamin into its physiologically active form

The Occupational Structure of Further and Higher Education in Ireland and the Netherlands

Although most types of education give access to a range of occupations, the educational background determines to a large extent the labour market possibilities of a worker. However, since educational systems vary widely between different countries, there is a question about the specific role of each type of education in a country and the influence of the structure of the educational system as a whole on the relationship between education and the labour market. In this paper a comparison of the occupational structure of further and higher education in Ireland and the Netherlands is made. This comparison is based on a common occupational classification, which provides the possibility of measuring the extent of the occupational domains of types of education and the overlap in occupational domain of different types of education within each country and between both countries. The extent of the occupational domain and the similarities within a country provide information about aspects of the occupational structure of higher education in both countries, while the similarities between types of education in both countries make it possible to determine in a simple way the mutual position of types of education in the two countries. It is shown in the paper that since the Irish education system is more generally oriented than the Dutch system, Ireland has a broader occupational domain for similar types of further and higher education, on average, than the Netherlands. In addition the occupational domains for academics and technicians in Ireland have more overlap between different fields of study than in the Netherlands. Furthermore, despite the fact that the fraction of higher educated people in the Netherlands considerably exceeds the fraction in Ireland – which might result in some qualifications inflation – some types of education in Ireland, such as engineering and agricultural science, at higher levels seem to be closer to the Dutch intermediate vocational level than to the higher level.education, training and the labour market;

The optimal schedule for pulsar timing array observations

In order to maximize the sensitivity of pulsar timing arrays to a stochastic gravitational wave background, we present computational techniques to optimize observing schedules. The techniques are applicable to both single and multi-telescope experiments. The observing schedule is optimized for each telescope by adjusting the observing time allocated to each pulsar while keeping the total amount of observing time constant. The optimized schedule depends on the timing noise characteristics of each individual pulsar as well as the performance of instrumentation. Several examples are given to illustrate the effects of different types of noise. A method to select the most suitable pulsars to be included in a pulsar timing array project is also presented.Comment: 16 pages, 6 figures, accepted by MNRA

Theoretical He I Emissivities in the Case B Approximation

We calculate the He I case B recombination cascade spectrum using improved radiative and collisional data. We present new emissivities over a range of electron temperatures and densities. The differences between our results and the current standard are large enough to have a significant effect not only on the interpretation of observed spectra of a wide variety of objects but also on determinations of the primordial helium abundance.Comment: Accepted to ApJ

Paradoxical popups: Why are they hard to catch?

Even professional baseball players occasionally find it difficult to gracefully approach seemingly routine pop-ups. This paper describes a set of towering pop-ups with trajectories that exhibit cusps and loops near the apex. For a normal fly ball, the horizontal velocity is continuously decreasing due to drag caused by air resistance. But for pop-ups, the Magnus force (the force due to the ball spinning in a moving airflow) is larger than the drag force. In these cases the horizontal velocity decreases in the beginning, like a normal fly ball, but after the apex, the Magnus force accelerates the horizontal motion. We refer to this class of pop-ups as paradoxical because they appear to misinform the typically robust optical control strategies used by fielders and lead to systematic vacillation in running paths, especially when a trajectory terminates near the fielder. In short, some of the dancing around when infielders pursue pop-ups can be well explained as a combination of bizarre trajectories and misguidance by the normally reliable optical control strategy, rather than apparent fielder error. Former major league infielders confirm that our model agrees with their experiences.Comment: 28 pages, 10 figures, sumitted to American Journal of Physic

The distribution of aneurinpyrophosphate between the nucleus and the cytoplasm of chicken erythrocytes

The nuclei of chicken erythrocytes contain about 20 times as much aneurinpyrophosphate per unit volume as the cytoplasm