87 research outputs found
Honeybee Colony Vibrational Measurements to Highlight the Brood Cycle
Insect pollination is of great importance to crop production worldwide and honey bees are amongst its chief facilitators. Because of the decline of managed colonies, the use of sensor technology is growing in popularity and it is of interest to develop new methods which can more accurately and less invasively assess honey bee colony status. Our approach is to use accelerometers to measure vibrations in order to provide information on colony activity and development. The accelerometers provide amplitude and frequency information which is recorded every three minutes and analysed for night time only. Vibrational data were validated by comparison to visual inspection data, particularly the brood development. We show a strong correlation between vibrational amplitude data and the brood cycle in the vicinity of the sensor. We have further explored the minimum data that is required, when frequency information is also included, to accurately predict the current point in the brood cycle. Such a technique should enable beekeepers to reduce the frequency with which visual inspections are required, reducing the stress this places on the colony and saving the beekeeper time
Predictive Markers of Honey Bee Colony Collapse
Across the Northern hemisphere, managed honey bee colonies, Apis mellifera, are currently affected by abrupt depopulation during winter and many factors are suspected to be involved, either alone or in combination. Parasites and pathogens are considered as principal actors, in particular the ectoparasitic mite Varroa destructor, associated viruses and the microsporidian Nosema ceranae. Here we used long term monitoring of colonies and screening for eleven disease agents and genes involved in bee immunity and physiology to identify predictive markers of honeybee colony losses during winter. The data show that DWV, Nosema ceranae, Varroa destructor and Vitellogenin can be predictive markers for winter colony losses, but their predictive power strongly depends on the season. In particular, the data support that V. destructor is a key player for losses, arguably in line with its specific impact on the health of individual bees and colonies
Large-scale monitoring of effects of clothianidin-dressed oilseed rape seeds on pollinating insects in Northern Germany: effects on honey bees (Apis mellifera)
Dominance of Nosema ceranae in honey bees in the Balkan countries in the absence of symptoms of colony collapse disorder
New models of apprenticeship and equal employment opportunity : do training networks enhance fair hiring practices?
This study investigates whether occupational training networks enable the selection of apprentices to be less discriminatory. Training networks are a new organisational form of VET that is becoming increasingly widespread in Switzerland, as well as in Germany and Austria. In the Swiss model, an intermediary lead organisation recruits the candidates. It also attends to the apprenticeship itself and effects a placement of the young adults with the training network companies every year anew. The study is based on the sociology of conventions, which allows organisational mechanisms of selection in training institutions to be understood and the dangers of discrimination harboured therein to be appreciated. Based on a case study of a medium-sized training network, the study shows how this form of organisation permits a fairer selection, i.e. one that is gauged more by performance and less by social attributes of the applicants, as compared to selection processes in single SMB
Individual or Organizational Resources As Determinants of Success of Apprenticeship? The Need for Solving Organizational Problems As Motors behind Social InequalityIndividuelle oder organisationale Ressourcen als Determinanten des Bildungserfolgs? Organisatorischer Problemlosungsbedarf als Motor sozialer Ungleichheit
A recent sociological dispute serves to question the explanatory value of resource theories to account for inequality in labor market access. To explain educational success, human resource theories can be countered by organizational theories, in particular by the concept of Institutional Discrimination. The empirical plausibility of this concept is shown with regard to the distribution of apprenticeships in training firms. It is argued that by settling for a narrowed notion of individual productivity, previous research of social inequality has ignored significant organizational rationalities of selection in the educational field & in the labor market
Individual or Organizational Resources As Determinants of Success of Apprenticeship? The Need for Solving Organizational Problems As Motors behind Social InequalityIndividuelle oder organisationale Ressourcen als Determinanten des Bildungserfolgs? Organisatorischer Problemlosungsbedarf als Motor sozialer Ungleichheit
A recent sociological dispute serves to question the explanatory value of resource theories to account for inequality in labor market access. To explain educational success, human resource theories can be countered by organizational theories, in particular by the concept of Institutional Discrimination. The empirical plausibility of this concept is shown with regard to the distribution of apprenticeships in training firms. It is argued that by settling for a narrowed notion of individual productivity, previous research of social inequality has ignored significant organizational rationalities of selection in the educational field & in the labor market
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