4242 research outputs found
Sort by
Behavioural disturbances and underlying neurophysiological mechanisms during ocean acidification and warming in Gadus morhua and Boreogadus saida
Get PDFOcean acidification as projected for the end of the 21st century has the potential to cause behavioural alterations in fish with unclear consequences for affected species and ecosystems, both in the short and long term. Recent findings indicate that a change in functionality of A A aminobutyric acid receptors type A (GABAA-receptors) in the brain of fish due to acid-base regulatory processes may be the mechanism underpinning these behavioural disruptions. So far, studies have focused on the effects of CO2 on tropical and temperate species with no information about the relevance of these observations for polar species. The role of environmental temperature for CO2-induced behavioural changes is largely unknown, but highly important, as acidification and warming will occur simultaneously in marine ecosystems. In this thesis, behavioural effects of future CO2 conditions, the role of environmental temperature and the respective physiological background were analyzed in two cold water adapted fish species collected around Svalbard. Atlantic cod, Gadus morhua, is an invasive species currently shifting its distribution northward into colder waters where Polar cod, Boreogadus saida, is a native key species in the local food web. Shifting predator prey interactions and the differing potential of species to acclimate and adapt to future temperature and CO2 conditions will shape the future abundance of each species with concomitant impacts on the polar ecosystem. In manuscript I it is shown that the behaviour of B. saida is more sensitive to future environmental CO2 conditions than the behaviour of G. morhua. Nevertheless, the potential for behavioural resilience of G. morhua under high CO2 conditions may be dependent on the experienced environmental temperature and greatest under optimum temperature conditions. In manuscript II, metabolic changes are illustrated, which indicate CO2-dependent energy limitation in the brain of B. saida at 8 AAdegreeC, but not in G. morhua. However, in G. morhua, temperature and CO2-dependent alterations in GABA-metabolism were found potentially increasing this speciesa behavioural resistance against higher environmental CO2 partial pressures. In manuscript III, maintenance of intracellular pH in the brain of acutely CO2-exposed B. saida indicating sufficient acid-base regulatory processes is reported. However, long-lasting effects of CO2 on blood circulation were also observed with unclear relevance for the fitness of this species under expected ocean acidification scenarios. The results of this thesis indicate that G. morhua will be more capable to survive in warmer, more acidified waters around Svalbard than B. saida. Furthermore, the potential interplay between behaviour, GABA-metabolism and acid-base physiology with respect to their contribution to metabolic and behavioural resistance against environmental hypercapnia is discussed
Interview with Matthias Kempke on Ken Follett s The Pillars of the Earth
Get PDFMatthias Kempke, freelance game writer, narrative designer and creative consultant for games, speaks about his work on the 2D adventure game Ken Follett s The Pillars of the Earth (2017/2018) and his other projects
Inequalities in Health among Older Adults in Western Industrialised Countries : Explanations from Gender, Socioeconomic and Time Use Perspectives
Get PDFGender and socioeconomic inequalities in health persist in high-income countries, even at old age; yet, there is still no consensus about the best indicators of socioeconomic status to be used in health inequalities research among older adults, especially after retirement. Complementary social indicators that have been suggested to assess gender and socioeconomic inequalities in health outcomes at old age are social roles and time use activities. This thesis explores the social and economic inequalities in self-reported health among elderly men and women, using a combined framework of time use activities, socioeconomic status (SES) and family characteristics. It further explains gender and cross-national inequalities in health in some Western industrialised countries. The thesis is centered around three empirical studies focusing on different dimensions of social inequalities in health among elderly men and women. The studies are based on data from the Multinational Time Use Study (MTUS) on older men and women aged 65 years and above. It also consists of a framework paper with an introductory chapter and a discussion of methodological as well as content issues around the topic. Study I examined how time use activities, socioeconomic status and family characteristics impact the health of older adults, and the extent to which the associations varied by gender and across countries. It further examined the extent to which various social factors explain the gender inequalities in health at old age. Significant gender differences in self-reported health were found in Germany, Italy and Spain, but not in the United Kingdom and the United States. Further decomposition analysis showed that differences in time allocated to leisure activities and level of educational attainment accounted for the largest health gap between elderly men and women. The results also showed that whereas time devoted to paid work, housework and active leisure activities were positively associated with health, time allocated to passive leisure and personal activities were negatively related to health in both men and women. The magnitude of the associations however varied by gender and country. Study II investigated the extent to which the association between housework activities and health may be moderated by sleep duration among elderly men and women. The result showed that both short ( 7 hours) and long ( 8 hours) sleep duration were negatively associated with health for both genders. However, the interactive associations between total productive housework, sleep duration and health status varied considerably between men and women. Among women, long hours of housework combined with either short or long sleep was negatively associated with health. Study III examined whether stress defined in terms of time pressure plays a mediating role in the relationship between work-related activities (paid work and unpaid work) and health among elderly men and women. The results showed that socioeconomic status, demographic factors, stress and work-related time use activities after retirement had a significant direct influence on health among the elderly. The findings further revealed that although stress has a strong direct negative effect on the health of both genders, it does not indirectly influence the positive effects of work-related time use activities on health among older adults. The overall conclusion in this thesis is that social patterning of health inequalities persist at older ages in high-income countries. However, the magnitude of these inequalities differ across countries and are shaped by unequal distribution of social and time use resources. The results of this thesis thus demonstrate the need of using an integrated framework of social factors when analysing gender and cross-national inequalities in health among the elderly population
Produktionsbegleitende Messeinrichtung basierend auf digitaler Holografie
Get PDFFor industrial mass production of micro parts it is important to detect the tool wear. To avoid long machine down time the measurement tool should be fast and it should be used inside the production machine. In this thesis a measuring system based on digital holography was developed. The set-up was designed as a digital holographic microscope to detect and characterise wear at micro deep drawing tools within a deep drawing machine. Furthermore, the basic idea of comparative holography was used to give the opportunity to generate a state difference of a worn tool and its initial state. Beside the measuring system an evaluation tool was developed. Here, both were evaluated by detecting a state difference of a die of an upsetting machine which shows material lost at the edges and surface after upset wires
Ehrenamt im Krankenhaus - Tradition oder Thema der Zukunft? : Die Sicht von Leitungskräften, Personal und Ehrenamtlichen auf das Ehrenamt in der akutstationären Versorgung
Get PDFVolunteer services are a traditional part of hospitals. To cope with future tasks, politicians and experts value volunteer services as an integral component of the health care mix. However, little is known about how volunteering is perceived within hospitals and among staff. This study focuses the goals and expectancies of hospital leaders, hospital staff and volunteers. The results of group discussions in four German hospitals indicate that volunteer services are perceived as valuable complement to medical care and nursing care, especially with regard to patient orientation. Some topics inhibiting motivation or use of volunteer services were identified. As the relevance of voluntary work is increasing, integration of volunteers into the health care system should be improved. Moreover there is a need for initiatives to increase the appeal for volunteering and the knowledge of voluntary work in hospitals. Politics should give greater attention to volunteer services in hospitals and better support. To enhance the requirements, there is a need for more in-depth research on the effects of volunteer services in health care
Active Perception for Autonomous Systems : In a Deep Space Navigation Scenario
Get PDFAutonomous systems typically pursue certain goals for an extended amount of time in a self-sustainable fashion. To this end, they are equipped with a set of sensors and actuators to perceive certain aspects of the world and thereupon manipulate it in accordance with some given goals. This kind of interaction can be thought of as a closed loop in which a perceive-reason-act process takes place. The bi-directional interface between an autonomous system and the outer world is then given by a sequence of imperfect observations of the world and corresponding controls which are as well imperfectly actuated. To be able to reason in such a setting, it is customary for an autonomous system to maintain a probabilistic state estimate. The quality of the estimate -- or its uncertainty -- is, in turn, dependent on the information acquired within the perceive-reason-act loop described above. Hence, this thesis strives to investigate the question of how to actively steer such a process in order to maximize the quality of the state estimate. The question will be approached by introducing different probabilistic state estimation schemes jointly working on a manifold-based encapsuled state representation. On top of the resultant state estimate different active perception approaches are introduced, which determine optimal actions with respect to uncertainty minimization. The informational value of the particular actions is given by the expected impact of measurements on the uncertainty. The latter can be obtained by different direct and indirect measures, which will be introduced and discussed. The active perception schemes for autonomous systems will be investigated with a focus on two specific deep space navigation scenarios deduced from a potential mining mission to the main asteroid belt. In the first scenario, active perception strategies are proposed, which foster the correctional value of the sensor information acquired within a heliocentric navigation approach. Here, the expected impact of measurements is directly estimated, thus omitting counterfactual updates of the state based on hypothetical actions. Numerical evaluations of this scenario show that active perception is beneficial, i.e., the quality of the state estimate is increased. In addition, it is shown that the more uncertain a state estimate is, the more the value of active perception increases. In the second scenario, active autonomous deep space navigation in the vicinity of asteroids is investigated. A trajectory and a map are jointly estimated by a Graph SLAM algorithm based on measurements of a 3D Flash-LiDAR. The active perception strategy seeks to trade-off the exploration of the asteroid against the localization performance. To this end, trajectories are generated as well as evaluated in a novel twofold approach specifically tailored to the scenario. Finally, the position uncertainty can be extracted from the graph structure and subsequently be used to dynamically control the trade-off between localization and exploration. In a numerical evaluation, it is shown that the localization performance of the Graph SLAM approach to navigation in the vicinity of asteroids is generally high. Furthermore, the active perception strategy is able to trade-off between localization performance and the degree of exploration of the asteroid. Finally, when the latter process is dynamically controlled, based on the current localization uncertainty, a joint improvement of localization as well as exploration performance can be achieved. In addition, this thesis comprises an excursion into active sensorimotor object recognition. A sensorimotor feature is derived from biological principles of the human perceptual system. This feature is then employed in different probabilistic classification schemes. Furthermore, it enables the implementation of an active perception strategy, which can be thought of as a feature selection process in a classification scheme. It is shown that those strategies might be driven by top-down factors, i.e., based on previously learned information, or by bottom-up factors, i.e., based on saliency detected in the currently considered data. Evaluations are conducted based on real data acquired by a camera mounted on a robotic arm as well as on datasets. It is shown that the integrated representation of perception and action fosters classification performance and that the application of an active perception strategy accelerates the classification process
Impact of deep-sea mining on redox environment, biogeochemical processes and element fluxes within and from sediments of the Clarion-Clipperton Zone, Pacific Ocean
Get PDFThe economic interest in deep-sea mineral resources has grown in recent years. Minerals of interest include polymetallic nodules, which occur in extensive deposits at more than 4000 m water depth in the Clarion-Clipperton Zone (CCZ), NE Pacific Ocean. In light of recent technological advances in mining equipment, the CCZ represents a prospective area for commercial deep-sea mining. In the framework of this PhD thesis, sediments from four European contract areas for the exploration of polymetallic nodules in the CCZ and one of the protected Areas of Particular Environmental Interest (APEI) were investigated. Comprehensive pore-water and solid phase data were produced for undisturbed sediments and sediments from disturbance tracks of small-scale deep sea mining experiments. The presented studies provide new insights into the spatial and temporal variation of redox zonation, biogeochemical processes and element fluxes in the sediments and the impact of potential mining activities in the CCZ
Fundamental Bonding Concepts of Inorganic Chemistry Revisited
Get PDFThe bonding situation in a variety of systems from inorganic chemistry is analyzed by application of a variety of bond analysis methods from real space, orbital space und energy space - a complementary bonding analysis. Fundamental bonding concepts such as bond polarization, resonance, hyperconjugative interactions and hypervalency are analyzed by this approach. It is shown that a complementary bonding analysis is a powerful tool to tackle complex bonding situations. The analysis is based on theoretically obtained wavefunctions and on the novel approach of X-ray wavefunction refinement
Rückmeldungen aus Schulleistungstests an Lehrkräfte durch interaktive Informationsvisualisierungen
Get PDFTeaching staff are expected to be able to use results from comprehensive student achieve-ment tests to improve their instruction. For these data-driven decision-making processes, skills that could be denoted as data literacy are required. Research has shown, however, that in some cases these competencies are not sufficiently pronounced and that feedback is often difficult to understand. Furthermore, the research demonstrated that it is necessary to in-crease the comprehensibility of feedback by using data visualizations. Regional state insti-tutes for education tasked with providing feedback supported teaching staff by offering fur-ther training and handouts on how to use external achievement test results. The matter of increasing the comprehensibility of feedback remains unaddressed. This gap in the research will be taken up in this thesis, which uses the example of comparative achievement tests to approach the question of whether the comprehensibility of achievement-test feedback could be increased by using a feedback system with interactive information visualizations. As part of a study with a cross-sectional design, twenty primary school teachers compared a familiar paper-based feedback for achievement-test results with a new, interactive feedback system. First, the teachers participating in the study assessed the perceived time required to answer the questions asked about the test results. Secondly, the teachers assessed how useful the feedback formats were for answering the questions. The results show that, on average, the questions asked about the data could be answered significantly more quickly using the interactive information visualizations. Furthermore, interactive information visualizations are assessed as being significantly more useful on average. Matrix visualizations were prov-en to have particularly positive effects. For the co-variables only one significant effect was perceived: Teachers with a high level of data literacy assessed the interactive feedback sys-tem as being faster. Moreover, the teachers gave statements regarding requirements for an interactive feedback system and their attitudes and experiences in working with achievement tests. The findings of this study indicate that feedback systems with a user- and demand-oriented graphic layout are becoming more important
Konstruktionsprozesse schulischer Leistung in Zeugniskonferenzen - Ein Erfahrungsbericht zum Arbeiten mit der Grounded Theory-Methodologie im Rahmen einer studentischen Forschungsarbeit.
No full textEntlang einer Masterarbeit mit dem Titel Weil er sich da angestrengt hat - Konstruktionsprozesse schulischer Leistung in Zeugniskonferenzen werden in diesem Aufsatz zentrale Ergebnisse der Studie vorstellen sowie Erfahrungen mit der Reflexiven Grounded Theory als Forschungsstil und Auswertungsmethode qualitativer Forschungsdesigns geschildert. Der Aufsatz soll damit zum einen Einblicke in die Ergebnisse der ethnographischen Forschung in Zeugniskonferenzen geben. Dazu werden die organisationalen Logiken der kommunikativen Praxis in Zeugniskonferenzen aufgezeigt, in welcher die institutionelle Funktion der Leistungserfassung sowie der Selektionsentscheidungen vollzogen wird. Zum anderen gibt dieser Aufsatz einen Einblick in das Arbeiten mit der Grounded Theory-Methodologie aus der Perspektive einer Forschungsnovizin. Schließlich wird die Bedeutung des Memoschreibens als reflexives Tool sowie stabilisierendes und strukturierendes Instrument im Forschungsprozess mit der Grounded Theory-Methodologie beleuchtet