Judging where a ball will go: the case of curved free kicks in football

This study examined whether adding spin to a ball in the free kick situation in football affects a professional footballer’s perception of the ball’s future arrival position. Using a virtual reality set-up, participants observed the flight paths of aerodynamically realistic free kicks with (±600 rpm) and without sidespin. With the viewpoint being fixed in the centre of the goal, participants had to judge whether the ball would have ended up in the goal or not. Results show that trajectories influenced by the Magnus force caused by sidespin gave rise to a significant shift in the percentage of goal responses. The resulting acceleration that causes the ball to continually change its heading direction as the trajectory unfolds does not seem to be taken into account by the participants when making goal judgments. We conclude that the visual system is not attuned to such accelerated motion, which may explain why goalkeepers appear to misjudge the future arrival point of such curved free kicks. Electronic Supplementary Material  Supplementary material is available for this article at .     

Environmental innovation strategies: When and why NGOs go beyond public regulations

The concept of environmental innovation strategies (EIS) is introduced and discussed. The notion refers to the conduct by which non-governmental organisations (NGOs) act as policy entrepreneurs seeking to address environmental issues by going beyond the provisions of public regulations. Environmental innovation is understood as the product of a process of social interactions between heterogeneous types of actors, including NGOs. Three social mechanisms are introduced in order to capture the conditions enabling and motivating NGOs to pursue EIS, as well as the politics through which EIS are produced. These mechanisms are then discussed in the light of two in-depth case studies in Indonesia and Switzerland. The findings highlight the institutional frustration and mix of concerns that push NGOs to engage in EIS, as well as the non-spontaneous nature of environmental innovations. Innovation represents, in the end, a game of power that should be analysed as such.     

Uncertainty in establishing forest reference levels and predicting future forest-based carbon stocks for REDD+

Forest reference levels (FRLs) provide a benchmark for assessing reduced emissions from deforestation and forest degradation (REDD+), and they are central to demonstrate additionality of REDD+. Attaining realistic FRLs, however, is challenging, especially in complex mosaic landscapes. We established FRLs in northern Laos for different reference periods and tested them against actual carbon stock changes. Annual time series of Landsat satellite images were used to capture the subtle changes in carbon stocks in complex landscapes characterized by shifting cultivation. We found that FRLs differ considerably depending on the reference period chosen. Abrupt land-use changes occurred when hybrid maize replaced traditional shifting cultivation and forests, and this invalidated carbon stock trends that would have been predicted had the FRL been projected into the future. We conclude that demonstrating additionality of REDD+ in fast developing areas is difficult and that payment systems rewarding potential emission reductions against hypothetical extrapolation of FRLs are unlikely to be a cost-effective strategy.     

Challenging established narratives on soil erosion and shifting cultivation in Laos

The official environmental discourse in Laos describes a “chain of degradation” stretching from upland shifting cultivation, increased runoff and soil erosion to the siltation of wetlands and reservoirs. This perspective has had wide‐ranging impacts on rural development policy which, in the uplands, has long favoured forest conservation over agriculture. Integrating soil erosion and water sediment data with local perceptions of land degradation in an upland village of northern Laos, this study tests the validity of the official environmental discourse. Biophysical measurements made in a small agricultural catchment indicate a significant correlation between the spatial extent of cultivation and soil erosion rates. However, sediment yields recorded at the outlet of the catchment highlight relatively low levels of off‐site sediment exportation. Furthermore, farmers' perceptions suggest that local land degradation issues and crop yield declines could be less related to soil erosion than to agricultural land shortage, increased weed competition, and fertility losses resulting from the intensification of shifting cultivation. The study concludes that a better understanding and management of land degradation issues can be achieved by developing more inclusive and scientifically‐informed approaches to environmental perceptions and narratives.     

The recursive model as a new approach to validate and monitor activity sensors

Activity sensors are increasingly being used to monitor animal activity but current methods, used to validate the relationship between the motion sensor information and the actual behavior of animals, have weaknesses. This study aims to improve the methods used to estimate activity level from dual axis activity sensors and to validate the Tellus activity sensor for reindeer (Rangifer tarandus). We developed a new approach, the recursive model (a recursive application of a logistic regression), to predict continuous values of activity without biased estimations or previous modifications of the dataset. We compared this new recursive model approach with two traditional approaches: the tree classification method and the standard model (based on simple logistic regression). Estimations from the tree classification and the standard model were dependent on the dataset used for validation, whereas the recursive model gave unbiased estimations. Estimations from standard and recursive models were also more accurate (lower average absolute errors) than those from the tree classification method and they had a slightly better discriminatory power (higher percentage of good classification). We successfully applied the recursive model for the first time and validated the Tellus activity sensor for reindeer. Any user can apply our methodology to obtain their own equations of the relationship between activity sensor values and the level of activity of the individual, and users monitoring reindeer activity with Tellus activity sensor can directly apply the provided equations under appropriate conditions.     

Pedogenesis and nickel biogeochemistry in a typical Albanian ultramafic toposequence

This study aimed at relating the variability of Ni biogeochemistry along the ultramafic toposequence to pedogenesis and soil mineralogy. Hypereutric Cambisols dominate upslope; Cambic Vertisols and Fluvic Cambisols occur downslope. The soil mineralogy showed abundance of primary serpentine all over the sequence. It is predominant upslope but secondary smectites dominate in the Vertisols. Free Fe-oxides are abundant in all soils but slightly more abundant in the upslope soils. Whereas serpentines hold Ni in a similar and restricted range in every soil (approx. 0.3 %), Ni contents in smectites may vary a lot and Mg-rich and Al-poor smectites in the Vertisol could hold up to 4.9 % Ni. Ni was probably adsorbed onto amorphous Fe-oxides and was also exchangeable in secondary smectites. High availability of Ni in soils was confirmed by DTPA extractions. However, it varied significantly along the toposequence, being higher in upslope soils, where Ni-bearing amorphous Fe-oxides were abundant and total organic carbon higher and sensibly lower downslope on the Vertisols: Ni_DTPA varied from 285 mg kg^?1 in the surface of soil I (upslope) to 95.9 mg kg^?1 in the surface of Fluvic Cambisols. Concentration of Ni in Alyssum murale shoots varied from 0.7 % (Hypereutric Cambisols) to 1.4 % (Hypereutric Vertisol). Amazingly, Ni uptake by A. murale was not correlated to Ni_DTPA, suggesting the existence of specific edaphic conditions that affect the ecophysiology of A. murale upslope.     

From large-scale to micromachining: A review of force prediction models

In this paper, a review of work performed in the area of force modelling in metal cutting processes is presented. Past and present trends are described and criticised to compare their relevance with current requirements. Several approaches are reviewed, such as empirical, mechanistic and analytical models. The models’ ability to predict forces, from rough machining to finish machining, is analysed.