99 research outputs found

    Analysis of the Soil Foodweb Structure on Organic- and Conventional Dairy Farms

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    The below ground biodiversity of soil organisms plays an important role in the functioning of the soil ecosystem, and consequently the efficiency of the above ground plant production on dairy farms. However, for farmers, soil biology remains a black box. It is difficult to interpret soil biology on dairy farms and to identify management measures to improve it. The objective of this study was to investigate if it is possible to classify the soil foodweb structure on a dairy farm in relation to management practice

    Striving for excellence sometimes hinders high achievers : Performance-approach goals deplete arithmetical performance in students with high working memory capacity

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    We tested whether the goal to attain normative superiority over other students, referred to as performance-approach goals, is particularly distractive for high-Working Memory Capacity (WMC) students-that is, those who are used to being high achievers. Indeed, WMC is positively related to high-order cognitive performance and academic success, a record of success that confers benefits on high-WMC as compared to low-WMC students. We tested whether such benefits may turn out to be a burden under performance-approach goal pursuit. Indeed, for high achievers, aiming to rise above others may represent an opportunity to reaffirm their positive status-a stake susceptible to trigger disruptive outcome concerns that interfere with task processing. Results revealed that with performance-approach goals-as compared to goals with no emphasis on social comparison-the higher the students' WMC, the lower their performance at a complex arithmetic task (Experiment 1). Crucially, this pattern appeared to be driven by uncertainty regarding the chances to outclass others (Experiment 2). Moreover, an accessibility measure suggested the mediational role played by status-related concerns in the observed disruption of performance. We discuss why high-stake situations can paradoxically lead high-achievers to sub-optimally perform when high-order cognitive performance is at play

    Improving low achievers' academic performance at university by changing the social value of mastery goals

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    Recent research has shown that, in a University context, mastery goals are highly valued, and that students may endorse these goals either because they believe in their utility (i.e., social utility), in which case mastery goals are positively linked to achievement, or to create a positive image of themselves (i.e., social desirability), in which case mastery goals do not predict academic achievement. The present two experiments induced high vs. neutral levels of mastery goals' social utility and social desirability. Results confirmed that mastery goals predicted performance only when these goals were presented as socially useful but not socially desirable, especially among low achievers, those who need mastery goals the most to succeed

    The motivation to learn as a self-presentation tool among Swiss high school students : The moderating role of mastery goals' perceived social value on learning

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    Although it has been assumed that the motivation to learn - or mastery goal endorsement - positively predicts learning achievement, most empirical findings fail to demonstrate this relationship. In the present research, conducted in a Swiss high school, we adopted a social value approach to test the hypothesis that adolescent students' mastery goals do in fact predict learning, but only if these goals are perceived as highly useful for scholarly success (high social utility), and are not endorsed as a means to be appreciated by the teachers (low social desirability), a finding that has previously been observed among college students and on teacher-graded achievement measures only. Results demonstrate that in spite of potential peculiarities of an adolescent population, individual differences in mastery goals' perceived social utility and desirability moderate the mastery goal endorsement-learning achievement relation. Findings are discussed with regard to both theory development and educational practice

    Assessing does not mean threatening : the purpose of assessment as a key determinant of girls' and boys' performance in a science class

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    International audienceDans le domaine scientifique, plusieurs travaux pointent les performances plus faibles des filles, en comparaison de celles obtenues par les garçons, surtout lorsque la situation évaluative active le stéréotype négatif supposé à propos de leurs capacités. L'originalité de cette recherche a été de ne pas répliquer un effet de menace du stéréotype, cette étude a testé l'efficacité d'une évaluation orientée vers la maßtrise en gardant le caractÚre évaluatif de la situation et surtout a permis de prouver que cette situation offrait un environnement d'apprentissage équitable pour les filles et les garçons

    Verkenning verwerkingsopties bedrijfsmatig gemengd kunststofverpakkingsafval

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    Within this project, an inventory has been made of the suitable processing options for processing plastic packaging waste of the Dutch state government. Hereby the technical feasibility of different options is analysed, but also readiness in the Netherlands (within the next 5 years), related cost and environmental impact. The separately collected plastic packaging waste of the Dutch state government has been studied during the last months of 2018. The composition was studied both with regard to the material composition and the types of packages and objects that are present. This material was sampled from five different locations in twofold. The separately collected material is composed of 60% plastics, small amounts of beverage cartons and metals (both 3%) and two non-targeted materials – paper & board and organic materials – in relatively large amounts (both approximately 17%). Currently, this material cannot be processed in conventional sorting facilities for post-consumer plastic packaging waste due to the relatively high concentrations of both contaminants. Ideally, the collection method is adapted in such a manner that the concentration of both contaminants is lowered below 15% or even better below 10%. This can potentially be achieved by information campaigns towards the users, a change in the waste collection system (the size of the opening of the waste collection bins, use of icons and the grouping of the waste bins for the various materials). Subsequently, the separately collected plastic waste can be treated at conventional sorting facilities for post-consumer lightweight packaging waste. An existing model for post-consumer plastic packaging waste was used to approximate the flows of the plastic packages through conventional sorting and recycling companies. The model predicts that roughly 58 tons of washed milled goods can be made from the separately collected plastic packaging waste. In case these recycled plastics are used in applications where virgin plastics are replaced then this will approximately result in a reduction of the greenhouse gases of 239 tons CO2 equivalents. The research of alternative methods shows that only the mechanical recovery of plastics from residual waste is ready in the Netherlands. This demands that the residual waste of the Dutch government will be processed in a central waste sorting facility and this is financially less attractive. Magnetic density separation is likely to develop within 5 years’ time to a robust alternative, but with currently unknown financial consequences. Other alternative processing options are not yet ready or are only a partial solution. Therefore the current system of separate collection, sorting and mechanical recycling is – based on our current knowledge – the most suitable processing option for the next 5 years

    Interstellar Iron and Silicon Depletions in Translucent Sight Lines

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    We report interstellar FeII and SiII column densities toward six translucent sight lines (A_V >~ 1) observed with the Space Telescope Imaging Spectrograph (STIS). The abundances were determined from the absorption of SiII] at 2335 Angstroms, and several weak Fe transitions including the first reported detections of the 2234 Angstrom line. We derive an empirical f-value for the FeII 2234 Angstrom transition of log(f lambda) = -1.54 +/- 0.05. The observed sight lines sample a variety of extinction characteristics as indicated by their R_V values, which range from 2.6 - 5.8. The dust-phase abundances of both Si and Fe are positively correlated with the small-grain population (effective radii smaller than a few hundred micron) toward the targets. The physical conditions along the sight lines suggest that this relationship may be due to differences in the survival of small particles in some interstellar environments. The chemical composition of the small grains could either resemble dust mantles or be silicate rich.Comment: accepted for publication in Ap

    Effects of STN and GPi Deep Brain Stimulation on Impulse Control Disorders and Dopamine Dysregulation Syndrome

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    Impulse control disorders (ICDs) and dopamine dysregulation syndrome (DDS) are important behavioral problems that affect a subpopulation of patients with Parkinson's disease (PD) and typically result in markedly diminished quality of life for patients and their caregivers. We aimed to investigate the effects of subthalamic nucleus (STN) and internal globus pallidus (GPi) deep brain stimulation (DBS) on ICD/DDS frequency and dopaminergic medication usage.A retrospective chart review was performed on 159 individuals who underwent unilateral or bilateral PD DBS surgery in either STN or GPi. According to published criteria, pre- and post-operative records were reviewed to categorize patients both pre- and post-operatively as having ICD, DDS, both ICD and DDS, or neither ICD nor DDS. Group differences in patient demographics, clinical presentations, levodopa equivalent dose (LED), and change in diagnosis following unilateral/bilateral by brain target (STN or GPi DBS placement) were examined.28 patients met diagnostic criteria for ICD or DDS pre- or post-operatively. ICD or DDS classification did not differ by GPi or STN target stimulation. There was no change in DDS diagnosis after unilateral or bilateral stimulation. For ICD, diagnosis resolved in 2 of 7 individuals after unilateral or bilateral DBS. Post-operative development of these syndromes was significant; 17 patients developed ICD diagnoses post-operatively with 2 patients with pre-operative ICD developing DDS post-operatively.Unilateral or bilateral DBS did not significantly treat DDS or ICD in our sample, even though a few cases of ICD resolved post-operatively. Rather, our study provides preliminary evidence that DDS and ICD diagnoses may emerge following DBS surgery

    Subcutaneous or Transvenous Defibrillator Therapy.

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    BACKGROUND: The subcutaneous implantable cardioverter-defibrillator (ICD) was designed to avoid complications related to the transvenous ICD lead by using an entirely extrathoracic placement. Evidence comparing these systems has been based primarily on observational studies. METHODS: We conducted a noninferiority trial in which patients with an indication for an ICD but no indication for pacing were assigned to receive a subcutaneous ICD or transvenous ICD. The primary end point was the composite of device-related complications and inappropriate shocks; the noninferiority margin for the upper boundary of the 95% confidence interval for the hazard ratio (subcutaneous ICD vs. transvenous ICD) was 1.45. A superiority analysis was prespecified if noninferiority was established. Secondary end points included death and appropriate shocks. RESULTS: A total of 849 patients (426 in the subcutaneous ICD group and 423 in the transvenous ICD group) were included in the analyses. At a median follow-up of 49.1 months, a primary end-point event occurred in 68 patients in the subcutaneous ICD group and in 68 patients in the transvenous ICD group (48-month Kaplan-Meier estimated cumulative incidence, 15.1% and 15.7%, respectively; hazard ratio, 0.99; 95% confidence interval [CI], 0.71 to 1.39; P = 0.01 for noninferiority; P = 0.95 for superiority). Device-related complications occurred in 31 patients in the subcutaneous ICD group and in 44 in the transvenous ICD group (hazard ratio, 0.69; 95% CI, 0.44 to 1.09); inappropriate shocks occurred in 41 and 29 patients, respectively (hazard ratio, 1.43; 95% CI, 0.89 to 2.30). Death occurred in 83 patients in the subcutaneous ICD group and in 68 in the transvenous ICD group (hazard ratio, 1.23; 95% CI, 0.89 to 1.70); appropriate shocks occurred in 83 and 57 patients, respectively (hazard ratio, 1.52; 95% CI, 1.08 to 2.12). CONCLUSIONS: In patients with an indication for an ICD but no indication for pacing, the subcutaneous ICD was noninferior to the transvenous ICD with respect to device-related complications and inappropriate shocks. (Funded by Boston Scientific; PRAETORIAN ClinicalTrials.gov number, NCT01296022.)
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