451 research outputs found

    Well-defined silica-supported olefin metathesis catalysts

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    Two triethoxysilyl-functionalized N-heterocyclic carbene ligands have been synthesized and used to prepare the corresponding second-generation ruthenium olefin metathesis catalysts. These complexes were then grafted onto silica gel, and the resulting materials were efficient heterogeneous catalysts for a number of metathesis reactions. The solid-supported catalysts were shown to be recyclable over a number of reaction cycles, and no detectable levels of ruthenium were observed in reaction filtrates (ruthenium concentration of filtrate <5 ppb)

    'Hear Israel:' The involvement of Jews in education of the deaf

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    During the last two centuries there has been a methodological struggle over teaching the deaf. Do deaf people learn to communicate by means of gestures and signs (the "manual method") or is it important for them to learn speech and lip-reading (the "oral method")? In the second half of the nineteenth century, many schools for the deaf made the transition from the manual to the oral method, which the Milan conference of teachers of the deaf decided to promote in 1880. In this conversion, Jews played an important role. Yet there appears to be a clear link between their efforts and Jewish tradition, including its perception of the deaf. © 2008 The Author(s)

    Learning-associated gamma-band phase-locking of action-outcome selective neurons in orbitofrontal cortex

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    Gamma oscillations (30-100 Hz) correlate to a variety of neural functions, including sensory processing, attention, and action selection. However, they have barely been studied in relation to emotional processing and valuation of sensory signals and actions. We conducted multineuron and local field potential recordings in the orbitofrontal cortex (OFC) of rats performing a task in which they made go or no-go decisions based on two olfactory stimuli predicting appetitive or aversive outcomes. Gamma power was strongest during the late phase of odor sampling, just before go/no-go movement, and increased with behavioral learning. Learning speed was correlated to the slope of the gamma power increment. Spikes of OFC neurons were consistently timed to the gamma rhythm during odor sampling, regardless of the associated outcome. However, only a specific subgroup of cells showed consistent phase timing. These cells showed action-outcome selective activity, not during stimulus sampling but during subsequent movement responses. During sampling, this subgroup displayed a suppression in firing rate but a concurrent increment in the consistency of spike timing relative to gamma oscillations. In addition to gamma rhythm, OFC field potentials were characterized by theta oscillations during odor sampling. Neurons phase-locked to either theta or gamma rhythms but not to both, suggesting that they become associated with separate rhythmic networks involving OFC. Altogether, these results suggest that OFC gamma-band synchronization reflects inhibitory control over a subpopulation of neurons that express information about the emotional valence of actions after a motor decision, which suggests a novel mechanism for response inhibition

    Low Pressure Ethenolysis of Renewable Methyl Oleate in a Microchemical System

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    A microchemical system for ethenolysis of renewable methyl oleate was developed, in which the dual-phase, microfluidic design enabled efficient diffusion of ethylene gas into liquid methyl oleate through an increased contact area. The increased mass transfer of ethylene favored the formation of desired commodity chemicals with significantly suppressed homometathesis when compared to the bulk system. In addition to higher selectivity and conversion, this system also provides the typical advantages of a microchemical system, including the possibility of convenient scale-up

    De beslispraktijk van het Schadefonds Geweldsmisdrijven: een kwalitatieve studie naar de beoordeling van verzoeken tot tegemoetkoming

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    The Violent Offences Compensation Fund’s decision-making practice: A qualitative study into the evaluation of requests for compensation Victims who suffer severe damages due to the act of a violent crime can request state compensation from the Dutch Violent Offences Compensation Fund (VOCF). VOCF workers who decide on these requests use their discretionary powers to translate the VOCF’s rules and policy into concrete actions. This study investigated (1) to what extent these VOCF workers match Lipsky’s definition of street-level bureaucrats and (2) what routines and heuristics they use to deal with time and information constraints. On the basis of document analysis and interviews, we found that the decision makers of the VOCF can to a certain extent be seen as street-level bureaucrats. To make decisions timely, some of them use routines such as the ‘downstream orientation’. This means that they award requests for compensation if they think that the applicant would be able to successfully contest a rejecting decision. To deal with a lack of information, they sometimes include a review clause in the text of a rejection decision. The use of heuristics was not found among the lawyers who decide in first instance, but in case of appeal hearings heuristics such as the affect and representativeness heuristic seem to play a role in the decision-making process. Future research should investigate whether these routines and heuristics lead to disparities in outcomes. Criminal Justice: Legitimacy, accountability, and effectivit

    'Krijgt hij nog een kans, of rekenen we af?'. Rechters over de rol van het recidiverisico bij de straftoemeting

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    Het recidiverisico van de dader is in theorie een belangrijke straftoemetingsfactor indien gestraft wordt met het oog op speciale preventie. In deze studie onderzoeken we welke rol het recidiverisico in de praktijk speelt bij de straftoemetingsbeslissing van de rechter. Rechters zeggen aan hoog-risico-daders eerder bijzondere voorwaarden op te leggen en altijd op zoek te zijn naar aanknopingspunten dat de dader zijn leven wil beteren. Dit getuigt van een straftoemetingpraktijk die gekenmerkt wordt door penal welfarism. Desalniettemin worden hoog-risico-daders soms wel zwaarder bestraft, echter niet vanwege hun recidiverisico, maar vanwege hun sanctielijn: als daders hun kansen om hun leveren te beteren hebben vergooid, stappen rechters over op vergelding en incapacitatie. De straftoemetingspraktijk is dan ook een mix van traditionele vergeldingsgerichtheid, penal welfarism en new penology.Criminal Justice: Legitimacy, accountability, and effectivit
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