Comment on water pollution in Lake Michigan from pollution aerosol fallout

The hypothesis that air pollution is a major source of some water pollution trace elements in Lake Michigan (Winchester and Nifong, 1971) is reexamined. Hazards evaluation techniques are used to assess the overall transfer efficiency of pollution from air to the lake. This efficiency was found to be at least 25%, which supports the hypothesis. It is suggested that the problem be studied taking into account local mesoscale systems (such as lake breeze) and the distribution of air trajectory, wind speed and stability categories.     

Functional analysis of vegetation on alpine treeline ecotone in the Julian and Kamnik-Savinja Alps in Slovenia

Our study focused on the functional aspects of plant species and vegetation at the transition from larch (Larix decidua Mill.) forest to mountain pine (Pinus mugo Turra) stands on the alpine treeline ecotone. With increasing elevation, living conditions grow harsher, which is reflected in the plant species and functional trait composition of plant communities. At four different localities in the Slovenian Alps, relevés along an altitudinal gradient and according to vegetation type were made (European larch forests, larch trees-mountain pine shrubs, mountain pine shrubs), using standard Central European phytocoenological method. In the upper mountain pine belt, few differential species were found, since most species represented in mountain pine stands also occurred in the lower two vegetation belts, while there were many differential species in the lower forest belt. Species with considerable competitive ability and moderate stress tolerance dominated the upper treeline ecotone, whereas ruderality is poorly expressed. The importance of stress tolerance in plant strategies increased slightly in the mountain pine belt. Changes in the representation of some functional traits attributes were detected by vegetation belts, but complete species turnover did not occur. Changes in dominant life form involved greater cover of chamaephytes and nanophanerophytes in the upper mountain pine belt. Species with evergreen leaves dominated mountain pine stands and deciduous forest stands. The share of species with scleromorphic leaves increased in the direction of the mountain pine belt while the share of species with mesomorphic and hygromorphic leaves declined. Mountain pine stands create good conditions for the regeneration of tree species and colonisation by ecologically more demanding forest species while species of alpine grasslands withdraw on open areas. Since today’s treeline is lowered due to past human activity, an upward shift is expected. Also, considering the great importance of competition strategy, current conditions in mountain pine stands are favourable for future forest succession.     

Ensuring the validity of private forest owner typologies by controlling for response style bias and the robustness of statistical methods

In survey-based segmentation of forest owners, two threats to the validity of results have largely been ignored: (1) response style bias and (2) the robustness of the statistical methods. This study demonstrates response style bias detection, presents an approach for correcting for acquiescence – the systematic tendency to agree with survey items, and explores the sensitivity of a probabilistic clustering algorithm to requirements for the validity of the typology. Structural equation modeling and Monte Carlo data generation techniques were employed to detect acquiescence and estimate its effect on construct validity. A survey of the relevance of management information for private forest owners (N = 364) was used as an example. Although acquiescence was confirmed, it had minor effect on the results and no effect on the substantive construct. Uncertainty about the number of forest owner types and membership can be reduced by using probabilistic clustering and observing the number of clusters while changing the requirements for the validity of clusters. The expectation maximization algorithm proved to be robust even to stringent requirements for the validity of clusters. By controlling for response style and the robustness of statistical methods, the validity of private forest owner typologies can be better ensured.     

The Modeling of Production and Economic Indicators in Suckler Cows Herds

The aim of this study was to analyse the most important factors affecting the profitability of suckler cows herds in Slovakia in 2010. The economic models were used to verify whether the suckler cows farming is profitable without subsidies in the current production conditions in Slovakia as well as their optimal location in the agricultural natural conditions of Slovakia from the perspective of economic efficiency. The breeding of cattle, mainly for the beef meat production, has long been unprofitable as it is apparent also from the analysis of several studies. In the model without inclusion of subsidies, it was calculated that the suckler cows farming is unprofitable at the current production parameters and realization prices of calves. The losses per cow and year were ranged from -240ε in the model by using a combination of the maximum threshold values of input parameters to -818ε by using a combination of the minimum threshold values of the input parameters. In the models including of subsidies amount of loss and/or profit per cow and year varied depending on the input parameters mainly on natality, average daily gain, the realization price of calves and the level of subsidies provided to breeder as well. The economic results are ranged from -277ε to 724ε per cow and year. From economical as well as production point of view, the most appropriate agricultural natural regions for suckler cows farming in Slovakia are upland and highland regions.     

Kepler-16: a transiting circumbinary planet

We report the detection of a planet whose orbit surrounds a pair of low-mass stars. Data from the Kepler spacecraft reveal transits of the planet across both stars, in addition to the mutual eclipses of the stars, giving precise constraints on the absolute dimensions of all three bodies. The planet is comparable to Saturn in mass and size and is on a nearly circular 229-day orbit around its two parent stars. The eclipsing stars are 20 and 69% as massive as the Sun and have an eccentric 41-day orbit. The motions of all three bodies are confined to within 0.5° of a single plane, suggesting that the planet formed within a circumbinary disk.