Population parameters of small pelagic fishes caught off Tawi-Tawi, Philippines

Growth and mortality parameters, exploitation rates and annual recruitment patterns were estimated from monthly length-frequency samples for Sardinella longiceps, S. fimbriata, S. Albella, Decapterus macrosoma, Dipterygonatus balteatus, Rastrelliger faughni and Encrasicolina heteroloba. These results provide the first sets of stock parameter estimates for these species off Tawi-Tawi, Philippines. The growth parameters derived were found comparable with previous estimates available for the same species from other localities. Recruitment was noted to be year-round and bimodal. Estimates of fishing mortality and exploitation rate were found to be presently above appropriate levels

Cognitive coherence in the evluation of a novel single item

Article published in Judgement and Decision-Makin

Talking soil science with farmers

When agricultural researchers visit farms in order to gather information for their research programmes, farmers rarely get proper feedback. Research information on scientific concepts such as soil fertility and nutrient balances is often considered too abstract for them. Researchers in Kenya returned to farmers to discuss their results in the context of Farmer Field Schools. Through the workshops that ensued, they managed to find a common language to bridge the communication gap

Maize silage for dairy cows: mitigation of methane emissions can be offset bij and use change

Increasing the digestibility of cattle rations by feeding grains and whole plant silages from maize have been identified as effective options to mitigate greenhouse gas emissions. The effect of ploughing grassland for maize crops have not been taken into account yet. A intensive dairy farm is used as an example to demonstrate the trade offs by this type of land use change when more maize silage is fed to dairy cows. The model DAIRY WISE has been used to calculate the mitigation by the changed ration, the Introductory Carbon Balance Model to calculate the changes in soil organic carbon and nitrogen caused by ploughing grassland for maize crops. The losses of soil carbon and the loss of sequestration potential are much larger than the annual mitigation by feeding more maize. The ecosystem carbon payback time defines the years of mitigation that are needed before the emissions due to land use change are compensated. For ploughing grassland on sandy soils, the carbon payback time is 60 years. A higher global warming potential for methane can reduce the carbon payback time with 30%. Ploughing clay soils with a higher equilibrium level of soil organic matter increases the payback time by maximally 70%. The payback times occur only in the case of permanent maize cropping, grass maize rotations cause annual losses of nitrous oxide that are larger than the mitigation by feeding more maize

The Optimal Linear Quadratic Feedback State Regulator Problem for Index One Descriptor Systems

In this note we present both necessary and sufficient conditions for the existence of a linear static state feedback controller if the system is described by an index one descriptor system. A priori no definiteness restrictions are made w.r.t. the quadratic performance criterium. It is shown that in general the set of solutions that solve the problem constitutes a manifold. This feedback formulation of the optimization problem is natural in the context of differential games and we provide a characterization of feedback Nash equilibria in a deterministic context.linear quadratic optimal control;descriptor systems;static stabilizing state feedback control

The Open-Loop Discounted Linear Quadratic Differential Game for Regular Higher Order Index Descriptor Systems

In this paper we consider the discounted linear quadratic differential game for descriptor systems that have an index larger than one. We derive both necessary and sufficient conditions for existence of an open-loop Nash (OLN) equilibrium. In a small macro-economic stabilization game we illustrate that the corresponding optimal response is generically cyclic.linear quadratic differential games;open-loop information structure;descriptor systems

Dynamics of personal development on healthy students

The aim is to study the effectiveness of different physical training for the relatively healthy students. The study involved 1004 students. The directions of development of the students' positive personal qualities. Found that the positive development of personality of students observed mostly on the first and third year than in the second. Could not find significant differences between the growth estimates of development of personality traits of students in classes in the sample program and the program specializations. Found that the rate of development of students' personality traits minor: the average growth estimates for core positive personal qualities for 3 years does not exceed 10% of the maximum possible level. Recommended in the classroom more emphasis on developing positive personality traits. It is shown that special attention should be paid to the development of emotional stability of students and their tolerance towards other people

'Beregenen op maat' krijgt remote sensing techniek

Ruim tien jaar geleden is Beregenen op Maat in Nederland geïntroduceerd. In 2009 vonden de ZLTO en de provincie Noord-Brabant het tijd om Beregenen op Maat een nieuwe impuls te geven. Met nieuwe computertechnieken en modules hebben Wageningen UR Livestock Research en Basfood BV een geavanceerd computersysteem ontwikkeld, waarbij veehouders via internet een actueel beregeningsadvies krijgen. De eerste ervaringen zijn veelbelovend