812 resultados para Hidden champions
Resumo:
Actual school dropout among immigrant youth has been addressed in a number of studies, but research on hidden school dropout among immigrant students is rare. Thus, the objective of this paper is to analyze hidden school dropout among primary school students with an immigrant background. The analyses were performed using survey data of 1186 immigrant students in Swiss primary schools. Our results show that immigrant students’ academic achievement, their attitudes towards school-related values, and the quality of their relationships with classmates and teachers were significant predictors of their disengagement during classes. Moreover, our findings strongly suggest that those predictors that are important for actual school dropout are crucial for hidden school dropout as well. We conclude that low-achieving immigrant youth who do not value school and who have poor relationships with teachers and peers are especially at risk of hidden and, eventually, of actual school dropout.
Resumo:
Cryptic species, i.e. species that are morphologically hard to distinguish, have been detected repeatedly in various taxa and ecosystems. In order to evaluate the importance of this finding, we have to know in how far cryptic species differ in various aspects of their biology. The amphipod Gammarus fossarum is a key invertebrate in freshwater streams and contains several cryptic species. We examined the population genetic structure, genetic diversity and demographic history of two of them (type A and type B) using microsatellite markers and asked whether they show significant differences. We present results of population genetic analyses based on a total of 37 populations from the headwaters of two major European drainages, Rhine and Rhone. We found that, in both species, genetic diversity was geographically structured among and within drainages. For type A in the Rhine and type B in the Rhone, we detected significant patterns of isolation by distance. The increase of genetic differentiation with geographical distance, however, was much higher in type A than in type B. This result indicates substantial interspecific differences in population history and/or the extent of current gene flow between populations. In the Rhine, type B does not show evidence of isolation by distance, and population differentiation is relatively low across hundreds of kilometres. The majority of these populations also show signatures of recent bottlenecks. These patterns are consistent with a recent expansion of type B into the Rhine drainage. In summary, our results suggest considerable and previously unrecognized interspecific differences in the genetic structure of these cryptic keystone species.
Resumo:
The wealth of social information presented on Facebook is astound-ing. While these affordances allow users to keep up-to-date, they also produce a basis for social comparison and envy on an unprecedented scale. Even though envy may endanger users’ life satisfaction and lead to platform avoidance, no study exists uncovering this dynamics. To close this gap, we build on responses of 584 Facebook users collected as part of two independent studies. In study 1, we explore the scale, scope, and nature of envy incidents triggered by Face-book. In study 2, the role of envy feelings is examined as a mediator between intensity of passive following on Facebook and users’ life satisfaction. Con-firming full mediation, we demonstrate that passive following exacerbates envy feelings, which decrease life satisfaction. From a provider’s perspective, our findings signal that users frequently perceive Facebook as a stressful environ-ment, which may, in the long-run, endanger platform sustainability.
Resumo:
Why do new EU democracies engage in multilateralism? The dominant explanation proposes that new democracies use international treaties to lock in domestic reforms. This article offers a novel explanation as to why new EU democracies participate in multilateral treaties. We argue that ratifying a treaty serves three external signaling purposes (addressing recognition concerns; increasing strategic autonomy, and pleasing the EU). We test our argument through a mix of quantitative and qualitative methods. First, we apply event history analysis. Drawing on a new ratification data set comprising 76 multilateral treaties, we illustrate the prominent role of new EU democracies in multilateralism as compared to other new democracies. Second, to assess the importance of external signaling in the decision to ratify multilateral treaties, we examine parliamentary ratification debates in selected Central and Eastern European countries. Third, we compare parliamentary discussions across European and non-European new democracies to demonstrate the different motives driving their approaches toward multilateralism.
Resumo:
Acidic or EDTA-containing oral hygiene products and acidic medicines have the potential to soften dental hard tissues. The low pH of oral care products increases the chemical stability of some fluoride compounds and favours the incorporation of fluoride ions in the lattice of hydroxyapatite and the precipitation of calcium fluoride on the tooth surface. This layer has some protective effect against an erosive attack. However, when the pH is too low or when no fluoride is present these protecting effects are replaced by direct softening of the tooth surface. Oral dryness can occur as a consequence of medication such as tranquilizers, antihistamines, antiemetics and antiparkinsonian medicaments or of salivary gland dysfunction. Above all, patients should be aware of the potential demineralization effects of oral hygiene products with low pH. Acetyl salicylic acid taken regularly in the form of multiple chewable tablets or in the form of headache powder, as well as chewing hydrochloric acids tablets for the treatment of stomach disorders, can cause erosion. There is most probably no direct association between asthmatic drugs and erosion on the population level. Consumers and health professionals should be aware of the potential of tooth damage not only by oral hygiene products and salivary substitutes but also by chewable and effervescent tablets. Several paediatric medications show a direct erosive potential in vitro. Clinical proof of the occurrence of erosion after use of these medicaments is still lacking. However, regular and prolonged use of these medicaments might bear the risk of causing erosion. Additionally, it can be assumed that patients suffering from xerostomia should be aware of the potential effects of oral hygiene products with low pH and high titratable acidity.
Resumo:
Aviation security strongly depends on screeners' performance in the detection of threat objects in x-ray images of passenger bags. We examined for the first time the effects of stress and stress-induced cortisol increases on detection performance of hidden weapons in an x-ray baggage screening task. We randomly assigned 48 participants either to a stress or a nonstress group. The stress group was exposed to a standardized psychosocial stress test (TSST). Before and after stress/nonstress, participants had to detect threat objects in a computer-based object recognition test (X-ray ORT). We repeatedly measured salivary cortisol and X-ray ORT performance before and after stress/nonstress. Cortisol increases in reaction to psychosocial stress induction but not to nonstress independently impaired x-ray detection performance. Our results suggest that stress-induced cortisol increases at peak reactivity impair x-ray screening performance.
Resumo:
UNLABELLED (111)In-DOTA-exendin-4 SPECT/CT has been shown to be highly efficient in the detection of insulinomas. We aimed at determining whether novel PET/CT imaging with [Nle(14),Lys(40)(Ahx-DOTA-(68)Ga)NH2]exendin-4 ((68)Ga-DOTA-exendin-4) is feasible and sensitive in detecting benign insulinomas. METHODS (68)Ga-DOTA-exendin-4 PET/CT and (111)In-DOTA-exendin-4 SPECT/CT were performed in a randomized cross-over order on 5 patients with endogenous hyperinsulinemic hypoglycemia. The gold standard for comparison was the histologic diagnosis after surgery. RESULTS In 4 patients histologic diagnosis confirmed a benign insulinoma, whereas one patient refused surgery despite a positive (68)Ga-DOTA-exendin-4 PET/CT scan. In 4 of 5 patients, previously performed conventional imaging (CT or MR imaging) was not able to localize the insulinoma. (68)Ga-DOTA-exendin-4 PET/CT correctly identified the insulinoma in 4 of 4 patients, whereas (111)In-DOTA-exendin-4 SPECT/CT correctly identified the insulinoma in only 2 of 4 patients. CONCLUSION These preliminary data suggest that the use of (68)Ga-DOTA-exendin-4 PET/CT in detecting hidden insulinomas is feasible.
Resumo:
OBJECTIVE: To explore women's experience of unwanted pregnancy and induced abortion in Bolivia, where nearly all induced abortions are carried out in clandestine, unregulated, and unsafe conditions. METHODS: Qualitative and quantitative research methods, including focus group discussions, in-depth interviews and a structured survey of women of reproductive age, were used to explore the experience of unwanted pregnancy and induced abortion in poor urban areas of 5 Bolivian cities. RESULTS: Of the 1175 sexually experienced women surveyed, 13% reported having had an induced abortion. The methods they tried included surgical abortion, taking misoprostol, drinking herbal and chemical preparations, and inflicting physical trauma on themselves. Many women made multiple attempts before successfully terminating a pregnancy. Lack of knowledge and confusion about how to use misoprostol may have contributed to the complications that resulted in seeking postabortion care. CONCLUSION: Increased access to accurate information and counseling about abortion options are paramount if women are to make informed decisions and minimize health risks.
Resumo:
Cold-water corals, such as Lophelia pertusa, are key habitat-forming organisms found throughout the world's oceans to 3000 m deep. The complex three-dimensional framework made by these vulnerable marine ecosystems support high biodiversity and commercially important species. Given their importance, a key question is how both the living and the dead framework will fare under projected climate change. Here, we demonstrate that over 12 months L. pertusa can physiologically acclimate to increased CO2, showing sustained net calcification. However, their new skeletal structure changes and exhibits decreased crystallographic and molecular-scale bonding organization. Although physiological acclimatization was evident, we also demonstrate that there is a negative correlation between increasing CO2 levels and breaking strength of exposed framework (approx. 20-30% weaker after 12 months), meaning the exposed bases of reefs will be less effective 'load-bearers', and will become more susceptible to bioerosion and mechanical damage by 2100.