Weight change and quality of life in a community-based population

*Objectives:* This study investigates the longitudinal association between 5-year weight change and quality of life (QoL) in Dutch men and women.

*Design:* A prospective cohort study (1998, 2000, 2003) in a population based sample. Subjects: 2,414 men and women from the Maastricht region of the Netherlands.

*Measurements:* QoL outcomes were measured by the RAND-36 (eight subscales and two overall composite scores, physical and mental health (PCS and MCS)). Weight was measured on a scale. Weight change was calculated as change in weight between 1998 and 2003. In addition, 5-year weight change was also categorized in three groups: weight losers, weight maintainers, and weight gainers. All analyses were stratified for gender.

*Results:* A total of 598 men (50%) and 646 women (54%) maintained their weight, 177 men (15%) and 163 women (14%) lost more than 2.5 kg, and 410 men (35%) and 379 women (32%) gained more than 2.5 kg. Associations between 5-year weight change and QoL were found for MCS ([beta] = 0.13, 95% CI: 0.02|0.24) in women, and PCS ([beta] = -0.09, 95% CI: -0.17|-0.00; [beta] = -0.10, 95% CI: -0.19|-0.01) in men and women respectively. Moreover, associations between weight change and QoL were most pronounced for women of normal weight and obese men. Furthermore, in both genders, weight gainers showed a greater reduction on all physical components of QoL compared with weight maintainers. However, after 5-years weight gainers and weight losers did not significantly differ from weight maintainers in the mean change of MCS and PCS.

*Conclusion:* Weight gain was inversely associated with the physical domains of QoL in women and obese men. Conversely, in women, weight gain was positively associated with the mental domains of QoL. No differences between weight losers and weight gainers were found in mean change of QoL compared with weight maintainers

Towards a Robust Method of Modelling Leaf Appearance in Plants

The thermal interval for leaf tip appearance (phyllochron) is a critical variable for modelling plant development and growth. Phyllochron varies across environments, but is generally constant for a species grown in specific environments. For example, the phyllochron in maize is lower in temperate environments than in tropical and subtropical environments. The limitation of existing data is that each experiment has been evaluated in a narrow range of environments, and underlying mechanisms have not been adequately examined. Consequently, no method is available to model the variation across environments. Models use constant values that are fixed for particular environments. This situation is unsatisfactory, as model users must have values that have been determined for their locality. A method of adjusting the value of phyllochron according to genotype adaptation groups or environmental conditions is required. Of these two options, the latter appears most promising as there is little, if any, variation among genotypes when grown in specific environments. Recent information shows that phyllochron in maize is related to light intensity. The data also suggests that phyllochron depends on the adequacy of current photosynthesis (source) to meet the demands of the plant for growth (sink), one aspect of which is the production of new leaves. This paper reports on concepts and early progress in relating phyllochron to both irradiance and thermal time

Cosmic rays studied with a hybrid high school detector array

The LORUN/NAHSA system is a pathfinder for hybrid cosmic ray research combined with education and outreach in the field of astro-particle physics. Particle detectors and radio antennae were mainly setup by students and placed on public buildings. After fully digital data acquisition, coincidence detections were selected. Three candidate events confirmed a working prototype, which can be multiplied to extend further particle detector arrays on high schools.Comment: 10 pages, 6 figures. Nigl, A., Timmermans, C., Schellart, P., Kuijpers, J., Falcke, H., Horneffer, A., de Vos, C. M., Koopman, Y., Pepping, H. J., Schoonderbeek, G., Cosmic rays studied with a hybrid high school detector array, Europhysics News (EPN), Vol. 38, No. 5, accepted on 22/08/200

Applying Bayesian belief networks (BBNs) with stakeholders to explore and codesign options for water resource interventions

Bayesian Belief networks (BBNs) are a useful tool to account for uncertainty and can be used to incorporate stakeholder understandings of how a system works. In this study, BBNs were applied to elicit and discuss local stakeholders’ concerns in conflicts over water resource planning in two cases in southern Thailand. One concerned the construction of a dam proposed by a top-down project. The other concerned a bottom-up participatory process at the catchment scale to assess the need for water resources interventions and explore perceptions on alternative design options. In the top-down project, the responses of participants during the elaboration of the BBN showed that potentially affected stakeholders were particularly concerned about limited consultation and lack of shared benefits, which led them to oppose the dam project. In the bottom-up project, local stakeholders expected and agreed with the benefits of a dam, proposing to locate the dam upstream of community land. The BBN method did not facilitate dialogue in the top-down dam-building project because no alternative design options could be discussed and potentially affected stakeholders did not want to discuss compensation because of mistrust and differences in valuation of effects. In the bottom-up project, the BBN method did facilitate dialogue on alternative intervention options and their effects. The replicable BBN framework can support policy-makers to better understand water conflict situations in different stages of planning. Its application supports exploring a wider repertoire of options, enlarging the scope for more inclusive and sustainable solutions to water resource conflicts

An eccentric companion at the edge of the brown dwarf desert orbiting the 2.4 Msun giant star HIP67537

We report the discovery of a substellar companion around the giant star HIP67537. Based on precision radial velocity measurements from CHIRON and FEROS high-resolution spectroscopic data, we derived the following orbital elements for HIP67537$\,b$: m$_b$sin$i$ = 11.1$^{+0.4}_{-1.1}$ M$_{\rm {\tiny jup}}$, $a$ = 4.9$^{+0.14}_{-0.13}$ AU and $e$ = 0.59$^{+0.05}_{-0.02}$. Considering random inclination angles, this object has $\gtrsim$ 65% probability to be above the theoretical deuterium-burning limit, thus it is one of the few known objects in the planet to brown-dwarf transition region. In addition, we analyzed the Hipparcos astrometric data of this star, from which we derived a minimum inclination angle for the companion of $\sim$ 2 deg. This value corresponds to an upper mass limit of $\sim$ 0.3 M$_\odot$, therefore the probability that HIP67537$\,b$ is stellar in nature is $\lesssim$ 7%. The large mass of the host star and the high orbital eccentricity makes HIP67537$\,b$ a very interesting and rare substellar object. This is the second candidate companion in the brown dwarf desert detected in the sample of intermediate-mass stars targeted by the EXPRESS radial velocity program, which corresponds to a detection fraction of $f$ = 1.6$^{+2.0}_{-0.5}$%. This value is larger than the fraction observed in solar-type stars, providing new observational evidence of an enhanced formation efficiency of massive substellar companions in massive disks. Finally, we speculate about different formation channels for this object.Comment: Accepted for publication to A&

Modelling Kinetics of Plant Canopy Architecture - Concepts and Applications

Most crop models simulate the crop canopy as an homogeneous medium. This approach enables modelling of mass and energy transfer through relatively simple equations, and is useful for understanding crop production. However, schematisation of an homogeneous medium cannot address the heterogeneous nature of canopies and interactions between plants or plant organs, and errors in calculation of light interception may occur. Moreover, conventional crop models do not describe plant organs before they are visible externally e.g young leaves of grasses. The conditions during early growth of individual organs are important determinants of final organ size, causing difficulties in incorporating effects of environmental stresses in such models. Limited accuracy in describing temporal source-sink relationships also contributes to difficulty in modelling dry matter distribution and paramaterisation of harvest indices. Functional-architectural modelling overcomes these limitations by (i) representing crops as populations of individual plants specified in three dimensions and (ii) by modelling whole plant growth and development from the behaviour of individual organs, based on sound models of organs such as leaves and internodes. Since individual plants consist of numerous organs, generic models of organ growth applicable across species are desirable. Consequently, we are studying the development of individual organs, and parameterising it in terms of environmental variables and plant characteristics. Models incorporating plant architecture are currently applied in education, using dynamic visual representation for teaching growth and development. In research, the 3D representation of plants addresses issues presented above and new applications including modelling of pesticide distribution, fungal spore dispersal through splashing and plant to plant heterogeneity

Orbit and trajectory measurement with low intensity lead ion beams in the SPS

The orbit measurement system of the CERN SPS was designed to measure the position of dense proton beams with an intensity of up to 0.28 A. The lower design limit for the lead ion beam intensity has been fixed at 35mA. This requires a substantial extension of the dynamic range. We describe the properties of the system and its modifications together with the results obtained for sulphur ion beams in the past and lead ions more recently