Stand up Paddle Surfing-An Aerobic Workout and Balance Training

AbstractOriginating from an ancient Hawaiian tradition Stand Up Paddle Surfing (SUP) is a growing pastime and sports activity in which a person stands upright on a surfboard and propels it using a single paddle. During paddling the board constantly is in an unstable condition forcing paddlers to focus on keeping balance and simultaneously propelling the board by paddling. Therefore it is expected that SUP can be a high impact aerobic workout and balance training. A total of 68 subjects performed on-water and SUP ergometer trials, during ergometer trials heart rate (HR) was permanently measured and balance was assessed before and after all trials (ergometer and on-water) using a single leg hop test on a Win Pod electronic baropedometric platform. Results of the balance tests - though for a relatively small number of participants - showed that after ergometer trials a significant improvement in stability occurred whereas it was only significant for the right foot's anteroposterior movement after on-water trials. The result of the exercise-test illustrated that the HR of beginners stays in the aerobic zone which makes SUP suitable for endurance training

Preparative fractionation of a random copolymer (SAN) with respect to either chain length or chemical composition

The possibilities to fractionate copolymers with respect to their chemical composition on a preparative scale by means of the establishment of liquid/liquid phase equilibria were studied for random copolymers of styrene and acrylonitrile (san). Experiments with solutions of san in toluene have shown that fractionation does in this quasi-binary system, where demixing results from marginal solvent quality, take place with respect to the chain length of the polymer only. On the other hand, if phase separation is induced by a second, chemically different polymer one can find conditions under which fractionation with respect to composition becomes dominant. This opportunity is documented for the quasi-ternary system dmac/san/polystyrene, where the solvent dimethyl acetamide is completely miscible with both polymers. The theoretical reasons for the different fractionation mechanisms are discussed

Potential range of impact of an ecological trap network: the case of timber stacks and the Rosalia longicorn

Although the negative impact of timber stacks on populations of saproxylic beetles is a well-known phenomenon, there is relatively little data concerning the scale of this impact and its spatial aspect. Beech timber stored in the vicinity of the forest can act as an ecological trap for the Rosalia longicorn (Rosalia alpina), so in this study we have attempted to determine the spatial range of the impact of a network of timber stacks. Timber stacks in the species’ range in the study area were listed and monitored during the adult emergence period in 2014–2016. Based on published data relating to the species’ dispersal capabilities, buffers of four radii (500, 1000, 1600, 3000 m) were delineated around the stacks and the calculated ranges of potential impact. The results show that the percentage of currently known localities of the Rosalia longicorn impacted by stacks varies from 19.7 to 81.6%, depending on the assumed impact radius. The percentage of forest influenced by timber stacks was 77% for the largest-radius buffer. The overall impact of the ecological trap network is accelerated by fragmentation of the impact-free area. It was also found that forests situated close to the timber stacks where the Rosalia longicorn was recorded were older and more homogeneous in age and species composition than those around stacks where the species was absent. Such results suggest that timber stacks act as an ecological trap in the source area of the local population