8,090 research outputs found

    Towards an aims-led curriculum

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    Regional agreements and trade services - policy issues

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    Every major regional trade agreement now has a services dimension. Is trade in services so different that there is need to modify the conclusions on preferential agreements pertaining to goods reached so far? The authors first examine the implications of unilateral policy choices in a particular services market. They then explore the economics of international cooperation and identify the circumstances in which a country is more likely to benefit from cooperation in a regional rather than multilateral forum.Health Economics&Finance,Environmental Economics&Policies,Decentralization,Economic Theory&Research,Payment Systems&Infrastructure,Economic Theory&Research,Environmental Economics&Policies,Trade and Services,TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT,Trade and Regional Integration

    Towards a killer app for the Semantic Web

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    Killer apps are highly transformative technologies that create new markets and widespread patterns of behaviour. IT generally, and the Web in particular, has benefited from killer apps to create new networks of users and increase its value. The Semantic Web community on the other hand is still awaiting a killer app that proves the superiority of its technologies. There are certain features that distinguish killer apps from other ordinary applications. This paper examines those features in the context of the Semantic Web, in the hope that a better understanding of the characteristics of killer apps might encourage their consideration when developing Semantic Web applications

    Digital library economics : aspects and prospects

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    A review of the issues surrounding the economics of and economic justification for, digital libraries

    Neural circuits mediating aversive olfactory conditioning in Drosophila

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    Neural circuits mediating aversive olfactory conditioning in Drosophila

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    For all animals it is highly advantageous to associate an environmental sensory stimulus with a reinforcing experience. During associative learning, the neural representation of the sensory stimulus (conditioned stimulus; CS) converges in time and location with that of the reinforcer (unconditioned stimulus; US). The CS is then affiliated with a predictive value, altering the animal’s response towards it in following exposures. In my PhD thesis I made use of olfactory aversive conditioning in Drosophila to ask where these two different stimuli are represented and how they are processed in the nervous system to allow association. In the first part of my thesis, I investigated the presentation of the odor stimulus (CS) and its underlying neuronal pathway. CS-US association is possible even when the US is presented after the physical sensory stimulus is gone ('trace conditioning'). I compared such association of temporally non-overlapping stimuli to learning of overlapping stimuli ('delay conditioning'). I found that flies associate an odor trace with electric shock reinforcement even when they were separated with a 15 s gap. Memories after trace and delay conditioning have striking similarities: both reached the same asymptotic learning level, although at different rates, and both memories have similar decay kinetics and highly correlated generalization profiles across odors. Altogether, these results point at a common odor percept which is probably kept in the nervous system throughout and following odor presentation. In search of the physiological correlate of the odor trace, we used in vivo calcium imaging to characterize the odor-evoked activity of the olfactory receptor neurons (ORNs) in the antennal lobe (in collaboration with Alja Luedke, Konstanz University). After the offset of odor presentation, ORNs showed odor-specific response patterns that lasted for a few seconds and were fundamentally different from the response patterns during odor stimulation. Weak correlation between the behavioral odor generalization profile in trace conditioning and the physiological odor similarity profiles in the antennal lobe suggest that the odor trace used for associative learning may be encoded downstream of the ORNs. In the second part of the thesis I investigated the presentation of different aversive stimuli (USs) and their underlying neuronal pathways. I established an odor-temperature conditioning assay, comparable to the commonly used odor-shock conditioning, and compared the neural pathways mediating both memory types. I described a specific sensory pathway for increased temperature as an aversive reinforcement: the thermal sensors AC neurons, expressing dTrpA1 receptors. Despite the separate sensory pathways for odor-temperature and odor-shock conditioning, both converge to one central pathway: the dopamine neurons, generally signaling reinforcement in the fly brain. Although a common population of dopamine neurons mediates both reinforcement types, the population mediating temperature reinforcement is smaller, and probably included within the population of dopamine neurons mediating shock reinforcement. I conclude that dopamine neurons integrate different noxious signals into a general aversive reinforcement pathway. Altogether, my results contribute to our understanding of aversive olfactory conditioning, demonstrating previously undescribed behavioral abilities of flies and their neuronal representations

    The impact of incidental learning on the acquisition of the sound /p/ by Arabic-speaking EFL learners

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    The effect of incidental learning on acquiring the pronunciation of the phoneme /p/ by Arabic-speaking English as foreign language learners was the focus of this study. This phoneme was chosen because it does not exist in the phonemic inventory of Arabic. Eighth graders studying at Al-Ethra’a Secondary School in Alkarak were tested on the pronunciation of words containing /p/ in context (pretest). For three weeks, they were taught the primary stress of English words containing the target phoneme in their first or second syllable (treatment/incidental learning). The learning exercises consisted of explaining the stress rules and listening to native speakers uttering the words, followed by the participants’ repetition. The students were then re-tested (post-test) to determine whether incidental learning had affected the participants’ pronunciation of /p/. The results reveal that the treatment (incidental learning of /p/) had a positive impact on the participants\u27 answers on the post-test
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