Evaluation of Hungarian Wines for Resveratrol by Overpressured Layer Chromatography

A method, including solid phase extraction sample preparation, overpressured layer chromatographic separation and subsequent densitometric evaluation, was developed for measurement of total resveratrol (cis- and trans-isomers) content of wine. The amount of resveratrol was determined in wine samples from different winemaking regions of Hungary. The total resveratrol was high in Hungarian red wines (3.6–11 mg/L), and much lower in white ones (0.04–1.5 mg/L)

Geographic profiling applied to testing models of bumble-bee foraging

Geographical profiling (GP) was originally developed as a statistical tool to help police forces prioritize lists of suspects in investigations of serial crimes. GP uses the location of related crime sites to make inferences about where the offender is most likely to live, and has been extremely successful in criminology. Here, we show how GP is applicable to experimental studies of animal foraging, using the bumble-bee Bombus terrestris. GP techniques enable us to simplify complex patterns of spatial data down to a small number of parameters (2-3) for rigorous hypothesis testing. Combining computer model simulations and experimental observation of foraging bumble-bees, we demonstrate that GP can be used to discriminate between foraging patterns resulting from (i) different hypothetical foraging algorithms and (ii) different food item (flower) densities. We also demonstrate that combining experimental and simulated data can be used to elucidate animal foraging strategies: specifically that the foraging patterns of real bumble-bees can be reliably discriminated from three out of nine hypothetical foraging algorithms. We suggest that experimental systems, like foraging bees, could be used to test and refine GP model predictions, and that GP offers a useful technique to analyse spatial animal behaviour data in both the laboratory and field

Droplet entrainment prediction in horizontal flow by SYS-TH codes - Mantilla experiments - Recent analyses made with the FONESYS network

International audienceThe droplet entrainment in horizontal flow in water-cooled nuclear reactor plays an important role in many transients such as IB-LOCA and LB-LOCA. A benchmark of system thermal-hydraulic (SYS-TH) codes capabilities to predicting the onset of droplet entrainment and entrainment rate was conducted within FONESYS. FONESYS is a network among code developers who share the common objective to strengthen current technology, to highlight the capabilities and the robustness as well as the limitations of current SYS-TH codes to predict the main phenomena during transient scenarios in nuclear reactors for safety issues.Mantilla performed 49 air-water tests with the 2-inch test section and 19 tests with the 6-inch test section at low pressure and temperature. Tests were selected aiming to support and complement an on-going activity on the scalability of codes' closure laws, currently focusing on the horizontal stratification criteria and the onset of droplet entrainment and entrainment fraction criteria. Focus was put on the capability of ATHLET, CATHARE3, MARS-KS, RELAP5, RELAP5-3D, SPACE and TRACE in predicting the onset of droplet entrainment, the entrainment rate and pressure drops.Overall benchmark results show some spread in the results calculated by codes, highlighting the need for further research and development. Improving the capability in predicting dispersed flows might be beneficial for the analyses of different LOCA scenarios. The scalability of closure laws is discussed and possible ways for improving them are suggested

TPTF horizontal flow prediction by SYS-TH codes - Recent analyses made within the FONESYS network

International audienceThe horizontal stratification occurrence in WNCR plays an important role in many transients such as loss of coolant accidents and loss of residual heat removal by influencing the liquid mass repartition, the natural circulation and reflux condenser modes, and the break or leak flowrate. A benchmark activity on horizontal flow prediction was conducted in the framework of FONESYS. FONESYS is a network among code developers who share the common objective to strengthen current technology. The aim of the network is to highlight the capabilities and the robustness as well as the limitations of current SYS-TH codes to predict the main phenomena during transient scenarios in nuclear reactors for safety issues.One-hundred-twenty-six runs performed with the Two-Phase Test Facility (TPTF) were considered. Tests were selected aiming to support and complement an ongoing activity on the scalability of codes' closure laws, currently focusing on the horizontal stratification criteria and the onset of droplet entrainment and entrainment fraction criteria. Therefore, experiments performed with the 4-inch and 8-inch tests sections, at pressure ranging from 30 bar to 118 bar, in different flow regimes were considered. Focus was put on the capability of ATHLET, CATHARE 3, MARS-KS, RELAP5, RELAP5-3D, SPACE and TRACE in predicting void fractions, the transition to slug flow and the onset of droplet entrainment.Overall, the benchmark results show reasonably good capabilities of codes in predicting horizontal flow. However, some noticeable limitations emerged related to flow regime transition criteria, interfacial friction, and to the prediction of non-established flow. The scalability of closure laws and possible ways for improving them are discussed

Does intraspecific size variation in bumblebees allow colonies to efficiently exploit different flowers?

1. It has long been known that foraging bumblebee workers vary greatly in size, within species, and within single nests. This phenomenon has not been adequately explained. Workers of their relatives within the Apidae exhibit much less size variation.2. For the bumblebee Bombus terrestris size, as measured by thorax width, was found to correspond closely with tongue length, so that larger bees are equipped to feed from deeper flowers.3. The mean size of worker bees attracted to flowers was found to differ between plant species, and larger bees with longer tongues tended to visit deeper flowers.4. Finally, handling time depended on the match between corolla depth and tongue length: large bees were slower than small bees when handling shallow flowers, but quicker than small bees when handling deep flowers.5. Size variation within bumblebees may be adaptive, since it enables the colony as a whole to efficiently exploit a range of different flowers. Possible explanations for the marked differences in size variation exhibited by bumblebees compared with Apis species and stingless bees (Meliponinae) are discussed