16,275 research outputs found
Review of the methods to determine the hazard and toxicity of pesticides to bumblebees
Methods to determine the impact of pesticides on bumblebees are described. They are classified into laboratory tests to determine the acute toxicity and the hazard to bumblebees, (semi) field tests, and brood tests. The reproducibility and the significance of the data for practical purpose are discussed. Standardized laboratory toxicity tests supply reproducible data. In hazard tests, both in the laboratory and semi field tests, the exposure is not proportionate to the number of adult insects and the brood. Field tests provide realistic data on the hazard of a pesticide to bumblebee colonies but when the results are interpreted it must be taken in account that the test plot is only a portion of the total foraging area of a bumblebee colony. In a brood nest, due to the disorderly structure, only major effects can be recognized. Laboratory rearing of bumblebee brood should be developed to produce a standardized brood test that supplies reproducible dat
Infection and transmission of Nosema bombi in Bombus terrestris colonies and its effect on hibernation, mating and colony founding
The impact of the microsporidium Nosema bombi on Bombus terrestris was studied by recording mating, hibernation success, protein titre in haemolymph, weight change during hibernation, and colony founding of queens that were inoculated with N. bombi in the larval phase. Infection with N. bombi was diagnosed in 36% of B. terrestris queens exposed to N. bombi. Mating and hibernation of queens was not significantly affected by N. bombi infection but colony founding was reduced significantly. Haemolymph protein titre of N. bombi diseased queens was reduced, possibly indicating a disturbance of the metabolism. It was demonstrated that N. bombi infection was transmitted to the successive age cohorts in a colony and to the adults that were already in the colony prior to the introduction of the infection. The study showed a significant negative impact of N. bombi on B. terrestris colony development and indoor rearing
Overconfidence by Bayesian Rational Agents
This paper derives two mechanisms through which Bayesian-rational individuals with differing priors will tend to be relatively overconfident about their estimates and predictions, in the sense of overestimating the precision of these estimates. The intuition behind one mechanism is slightly ironic: in trying to update optimally, Bayesian agents overweight information of which they over-estimate the precision and underweight in the opposite case. This causes overall an over-estimation of the precision of the final estimate, which tends to increase as agents get more data.
Authority versus Persuasion
This paper studies a principal's trade-off between using persuasion versus using interpersonal authority to get the agent to 'do the right thing' from the principal's perspective (when the principal and agent openly disagree on the right course of action). It shows that persuasion and authority are complements at low levels of effectiveness but substitutes at high levels. Furthermore, the principal will rely more on persuasion when agent motivation is more important for the execution of the project, when the agent has strong intrinsic or extrinsic incentives, and, for a wide range of settings, when the principal is more confident about the right course of action.
What research we no longer need in neurodegenerative disease at the end of life : The case of research in dementia
A complete silence. That was what we got back from the European experts who had been energetically discussing research priorities in palliative care in neurodegenerative disease (ND) until a short while ago.1 The chair, an entertaining professor with good manners, must have felt the unease and quickly refocused the group to their task. But, wasn’t this the best question of all day? What research we no longer need? As scientists able to consider different perspectives, shouldn’t we have some idea of what research is, by contrast, no longer necessary? Palliative care research and research with people who have ND and are at the end of their life is, by definition, difficult. Making choices is a sensitive issue, but funds are limited. Therefore, we take a counterpoint to the research agenda recently reported by European Union (EU) Joint Programme – Neurodegenerative Disease Research (JPND),1 and consider whether there are studies we no longer need or are low priority, taking the example of dementiaPeer reviewedFinal Accepted Versio
Spaceprint: a Mobility-based Fingerprinting Scheme for Public Spaces
In this paper, we address the problem of how automated situation-awareness
can be achieved by learning real-world situations from ubiquitously generated
mobility data. Without semantic input about the time and space where situations
take place, this turns out to be a fundamental challenging problem.
Uncertainties also introduce technical challenges when data is generated in
irregular time intervals, being mixed with noise, and errors. Purely relying on
temporal patterns observable in mobility data, in this paper, we propose
Spaceprint, a fully automated algorithm for finding the repetitive pattern of
similar situations in spaces. We evaluate this technique by showing how the
latent variables describing the category, and the actual identity of a space
can be discovered from the extracted situation patterns. Doing so, we use
different real-world mobility datasets with data about the presence of mobile
entities in a variety of spaces. We also evaluate the performance of this
technique by showing its robustness against uncertainties
Culture Clash: The Costs and Benefits of Homogeneity
This paper develops an economic theory of the costs and benefits of corporate culture -- in the sense of shared beliefs and values -- in order to study the effects of 'culture clash' in mergers and acquisitions. I first use a simple analytical framework to show that shared beliefs lead to more delegation, less monitoring, higher utility (or satisfaction), higher execution effort (or motivation), faster coordination, less influence activities, and more communication, but also to less experimentation and less information collection. When two firms that are each internally homogenous but different from each other, merge, the above results translate to specific predictions how the change in homogeneity will affect firm behavior. The paper's predictions can also serve more in general as a test for the theory of culture as homogeneity of beliefs.
The development of a mapping tool for the evaluation of building systems for future climate scenarios on European scale
The paper presents a tool for the mapping of the performance of building
systems on European scale for different (future) time periods. The tool is to
use for users and be applicable for different building systems. Users should
also be able to use a broad range of climate parameters to assess the influence
of climate change on these climatic parameters. Also should the calculation
time be reasonable short. The mapping tool is developed in MATLAB, which can be
used by other users for their own studies.Comment: 21 pages, 24 figures, pre-conferenc
Housing subsidisation in the Netherlands; measuring its distortionary and distributional effects
This paper measures the distortionary and distributional effects of housing subsidies. The results are discussed in the light of the main justifications for subsidising housing, i.e. the merit-good argument, external effects and the distribution motive. Our measurements reveal some patterns of subsidisation that seem difficult to justify on these grounds. This applies especially to the differences between subsidisation of rental and owner-occupied housing, the differences between mortgage- and equity-financed ownership and the increase of relative subsidisation above a certain income level.
Helping the poor manage risk better : the role of social funds
Recent trends in trade, technology, and politics have created new opportunities for global welfare improvement, but have also increased risks. This challenge requires rethinking social protection, and its instruments, particularly social funds. This paper reviews social funds, and suggests future directions by using a"social risk management"framework, to examine how social funds can help the poor manage risk better. Risk management covers risk reduction, risk mitigation, and risk coping. Analyzing social funds within the social risk management framework, suggests that: they should be assessed as one of many components in countries'social risk management strategies; they should move from coping and mitigation, to risk reduction; they should focus more on the medium term impact of projects; their targeting should focus on vulnerability, and vulnerable groups; their"investment menus"should be expanded to include more risk reduction projects; and, more emphasis should be given to participation, and capacity building.Banks&Banking Reform,Social Risk Management,Environmental Economics&Policies,Rural Poverty Reduction,Safety Nets and Transfers
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