164 research outputs found

    Neural Correlates of Experience-Induced Deficits in Learned Vocal Communication

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    Songbirds are one of the few vertebrate groups (including humans) that evolved the ability to learn vocalizations. During song learning, social interactions with adult models are crucial and young songbirds raised without direct contacts with adults typically produce abnormal songs showing phonological and syntactical deficits. This raises the question of what functional representation of their vocalizations such deprived animals develop. Here we show that young starlings that we raised without any direct contact with adults not only failed to differentiate starlings' typical song classes in their vocalizations but also failed to develop differential neural responses to these songs. These deficits appear to be linked to a failure to acquire songs' functions and may provide a model for abnormal development of communicative skills, including speech

    Investigating attentional processes in depressive-like domestic horses (Equus caballus).

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    Some captive/domestic animals respond to confinement by becoming inactive and unresponsive to external stimuli. Human inactivity is one of the behavioural markers of clinical depression, a mental disorder diagnosed by the co-occurrence of symptoms including deficit in selective attention. Some riding horses display 'withdrawn' states of inactivity and low responsiveness to stimuli that resemble the reduced engagement with their environment of some depressed patients. We hypothesized that 'withdrawn' horses experience a depressive-like state and evaluated their level of attention by confronting them with auditory stimuli. Five novel auditory stimuli were broadcasted to 27 horses, including 12 'withdrawn' horses, for 5 days. The horses' reactions and durations of attention were recorded. Non-withdrawn horses reacted more and their attention lasted longer than that of withdrawn horses on the first day, but their durations of attention decreased over days, but those of withdrawn horses remained stable. These results suggest that the withdrawn horses' selective attention is altered, adding to already evidenced common features between this horses' state and human depression

    Überwachung der Kfz-Emissionen im realen Verkehr, Methoden und Ergebnisse

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    Systematic monitoring of real driving emissions from vehicles started in the 1990’ies with measurements for the Handbook on Emission factors (HBEFA, http://www.hbefa.net/e/index.html). From 2000 to 2005, a European consortium improved the methods for vehicle testing and evaluation in the EU FP7 Project ARTEMIS. Results from this project are e.g. the ARTEMIS driving cycle (CADC), frequently used for real world LDVs chassis dyno tests, and the ERMES data base, where test results from independent European labs are brought together. Based on the ARTEMIS core consortium, the ERMES group was established (http://www.ermes-group.eu/web/). The ERMES group consists of laboratories, funding organisations and researchers dealing with emission testing with PEMS and on the dynamometer, with remote sensing measurement and with corresponding analysis of measures and technologies to reduce emissions and energy consumption of road vehicles and mobile machines. While the ERMES database on real world tests had only a limited number of cars until HBEFA version 3.1 (e.g. 24 different EURO 5 diesel cars measured), the available data significantly increased during the last 3 years (e.g. covering today 101 EURO 5 and 85 EURO 6 diesel cars). Also for HDVs and 2-wheelers the number of measured vehicles increased significantly after the recent discussions on real world NOx emissions from diesel LDVs. Parallel to the conventional vehicle tests also remote sensing has been systematically developed for vehicle emission monitoring. Remote sensing measures the incremental concentration of gases in the exhaust plume of passing vehicles and thus provides mass emissions per mass of CO2. The number plate is used to identify make and model, engine type, year of registration and emission standard. This information is then associated with the measured instantaneous emissions. Since remote sensing measures thousands of vehicles per day, the data is very useful for the analysis of trends, which need a high number of vehicles to be representative. E.g., Remote Sensing can monitor aging and temperature influences and emission levels per EURO class, brand and possibly vehicle model also as basis for the selection of vehicles for more detailed instrumented tests. The paper describes the methods developed for the monitoring and evaluation and shows actual trends in vehicle emissions

    Does Work Affect Personality? A Study in Horses

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    It has been repeatedly hypothesized that job characteristics are related to changes in personality in humans, but often personality models still omit effects of life experience. Demonstrating reciprocal relationships between personality and work remains a challenge though, as in humans, many other influential factors may interfere. This study investigates this relationship by comparing the emotional reactivity of horses that differed only by their type of work. Horses are remarkable animal models to investigate this question as they share with humans working activities and their potential difficulties, such as “interpersonal” conflicts or “suppressed emotions”. An earlier study showed that different types of work could be associated with different chronic behavioural disorders. Here, we hypothesised that type of work would affect horses' personality. Therefore over one hundred adult horses, differing only by their work characteristics were presented standardised behavioural tests. Subjects lived under the same conditions (same housing, same food), were of the same sex (geldings), and mostly one of two breeds, and had not been genetically selected for their current type of work. This is to our knowledge the first time that a direct relationship between type of work and personality traits has been investigated. Our results show that horses from different types of work differ not as much in their overall emotional levels as in the ways they express emotions (i.e. behavioural profile). Extremes were dressage horses, which presented the highest excitation components, and voltige horses, which were the quietest. The horses' type of work was decided by the stall managers, mostly on their jumping abilities, but unconscious choice based on individual behavioural characteristics cannot be totally excluded. Further research would require manipulating type of work. Our results nevertheless agree with reports on humans and suggest that more attention should be given to work characteristics when evaluating personalities

    The challenge of designing a Fischer-Tropsch reactor

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    Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.The Fischer-Tropsch process converts synthesis gas, a mixture of carbon monoxide and hydrogen, to a spectrum of predominantly hydrocarbon products. The reaction is catalysed by cobalt, iron, nickel or ruthenium at elevated temperatures and pressures. In our studies of this system we developed a thermo-kinetic model of the reactor. One of the main challenges for the design of this type of reactor is the exothermicity of the reaction. Heat removal is critical to avoid catalyst deactivation and damage. To assess the heat removal it was therefore necessary to develop a descriptive model of the reactor. The overall process design we are developing is based on the results of an application of our process synthesis methodologies. These methods involved initially the definition and description of the fundamental processes taking place which are reaction and heat transfer. Thus in order to achieve an optimised design we needed to consider not only the reaction rate but also the rate of heat removal. Ideally, one would prefer a highly active catalyst to increase production per unit volume. However, the advantage of a highly active catalyst is offset by the necessity to equivalently enhance the heat removal to avoid damaging or destroying the catalyst. This requires the reactor designs to accommodate a trade-off between unit volume production rate and heat removal. This paper will address the issues involved in the thermodynamics, mass and heat transfer aspects of the Fischer-Tropsch reactor. This is further complicated by the high number of components and the multiple phases involved in the reactor. However due to the sensitivity of some information for commercial purposes in our research centre, relative values have been assigned to critical variables. This however does not compromise the quality of work.cs201

    Adult-Young Ratio, a Major Factor Regulating Social Behaviour of Young: A Horse Study

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    Adults play an important role in regulating the social behaviour of young individuals. However, a few pioneer studies suggest that, more than the mere presence of adults, their proportions in social groups affect the social development of young. Here, we hypothesized that aggression rates and social cohesion were correlated to adult-young ratios. Our biological model was naturally-formed groups of Przewalski horses, Equus f. przewalskii, varying in composition.We investigated the social interactions and spatial relationships of 12 one- and two-year-old Przewalski horses belonging to five families with adult-young ratios (AYR) ranging from 0.67 to 1.33. We found striking variations of aggression rates and spatial relationships related to the adult-young ratio: the lower this ratio, the more the young were aggressive, the more young and adults segregated and the tighter the young bonded to other young.This is the first study demonstrating a correlation between adult-young ratios and aggression rates and social cohesion of young individuals in a naturalistic setting. The increase of aggression and the emergence of social segregation in groups with lower proportions of adults could reflect a related decrease of the influence of adults as regulators of the behaviour of young. This social regulation has both theoretical and practical implications for understanding the modalities of the influence of adults during ontogeny and for recommending optimal settings, as for instance, for schooling or animal group management
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