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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Zusammenhang zwischen posttraumatischen Riechstörungen und Läsionen des präfrontalen Kortex

Lindner, Kyri-Kristin 28 January 2020 (has links)
Ziel: Das Ziel der vorliegenden Studie war einen Zusammenhang zwischen posttraumatischen Riechstörungen und Frontalhirnläsionen zu beweisen. Methode: Dafür wurden 51 Patienten mit posttraumatischen Riechstörungen und 50 Patienten mit Riechstörungen anderer Ätiologie untersucht. Der Grad der Riechstörungen wurde mit dem orthonasalen Testverfahren der Sniffin‘ Sticks sowie dem retronasalem Schmeckpulvertest eingestuft. Zusätzlich wurden neuropsychologische Tests (TMT-A, COWA, WCST, d2-R) durchgeführt, um Funktionen, die als typisch für die Frontallappen angesehen werden, zu überprüfen. Außerdem sollte jeder Patient den Fragebogen des Beck Depressions Inventars für eine Einschätzung seiner depressiven Tendenz beantworten. Ergebnisse: Es konnte in beiden untersuchten Patientengruppen kein Zusammenhang zwischen dem Riechvermögen und der neuropsychologischen Leistung festgestellt werden. Allerdings wurde in der posttraumatischen Patientengruppe eine signifikante, inverse Korrelation zwischen der Punktzahl des BDI und der Punktzahl im Diskriminationstest beobachtet. In der Kontrollgruppe bestand zwischen diesen Faktoren kein Zusammenhang. Schlussfolgerungen: Trotz der Ergebnisse dieser Studie kann ein Zusammenhang zwischen posttraumatischen Riechstörungen und Frontalhirnläsionen nicht ausgeschlossen werden, da u.a. die Funktionen der Frontallappen aufgrund ihrer Komplexität und Unspezifität schwierig zu messen sind. Außerdem waren die Traumata der Patienten sowie der klinische Verlauf sehr variabel und individuell. Frontalhirnläsionen können allerdings dramatische Einschnitte bedeuten, auf die klinisch besonders geachtet werden sollte. Olfaktorische Probleme können darüber hinaus zusätzlich die Lebensqualität stark beeinträchtigen und sollten daher ebenfalls Bestandteil der posttraumatischen Diagnostik sein.:Inhaltsverzeichnis 1 ABKÜRZUNGSVERZEICHNIS IV 2 EINLEITUNG 1 2.1 POSTTRAUMATISCHER RIECHVERLUST 1 2.2 FRONTALHIRN 3 3 ZIELSETZUNG DER STUDIE 9 3.1 HYPOTHESE 9 3.2 ERWARTETE ERGEBNISSE 10 4 MATERIAL UND METHODEN 10 4.1 PATIENTEN 10 4.2 METHODEN 10 4.2.1 RIECHTESTS 10 4.2.2 NEUROPSYCHOLOGISCHE TESTS 17 4.3 STATISTISCHE AUSWERTUNG 24 5 ERGEBNISSE 25 5.1 DESKRIPTIVE STATISTIK 25 5.1.1 PATIENTENKOLLEKTIV 25 5.1.2 POSTTRAUMATISCHE PATIENTEN 27 5.1.3 KONTROLLGRUPPE 28 5.2 KORRELATIONSPRÜFUNGEN 29 5.2.1 KORRELATION DER ERGEBNISSE DER RIECHTESTS MIT DEN ERGEBNISSEN DER NEUROPSYCHOLOGISCHEN TESTS 29 5.2.2 KORRELATION DER NEUROPSYCHOLOGISCHEN TESTS UNTEREINANDER 35 5.2.3 KORRELATION DER ERGEBNISSE DER RIECHTESTS MIT DER PUNKTZAHL DES BDI 36 6 DISKUSSION 39 6.1 METHODEN 40 6.1.1 RIECHTESTS 40 6.1.2 NEUROPSYCHOLOGISCHE TESTS 41 6.1.3 BECK DEPRESSIONS INVENTAR 43 6.2 ERGEBNISSE 43 6.2.1 ZUSAMMENHANG RIECHLEISTUNG MIT ERGEBNISSEN DER NEUROPSYCHOLOGISCHEN TESTS 43 6.2.2 ZUSAMMENHANG DISKRIMINATIONSLEISTUNG MIT PUNKTZAHL DES BECK DEPRESSIONS INVENTARS 48 7 AUSBLICK 50 8 ZUSAMMENFASSUNG 52 9 SUMMARY 53 10 ABBILDUNGSVERZEICHNIS V 11 TABELLENVERZEICHNIS VII 12 LITERATURVERZEICHNIS VIII 13 ERKLÄRUNG ZUR ERÖFFNUNG DES PROMOTIONSVERFAHRENS XXI 14 EINHALTUNG DER AKTUELLEN GESETZLICHEN VORGABE XXII 15 DANKSAGUNG XXIII 16 CURRICULUM VITAE XXIV 17 PUBLIKATIONEN XXVI
62

Large-Scale Application of a Telephone-Based Test of Cognitive Functioning in Older Adults

Breitling, Lutz P., Wolf, Melanie, Müller, Heiko, Raum, Elke, Kliegel, Matthias, Brenner, Hermann January 2010 (has links)
Aims: The study of cognitive functioning in large epidemiological settings is hampered by a lack of instruments for the remote assessment of cognitive performance, especially when targeting variability across the full range of adult functioning. The present study examined the practicability of such investigations using a recently developed telephone interview (Cognitive Telephone Screening Instrument, COGTEL). Methods: A subcohort of an ongoing epidemiological study in the elderly German population (ESTHER) was interviewed via telephone by trained personnel. These data were combined with sociodemographic information obtained by standardized self-administered questionnaires, and analysed by tabulation, histograms and regression models. Results: A total of 1,697 interviews could be analysed. The eligible participants had a mean age ± standard deviation of 74.0 ± 2.8 years. The COGTEL total scores closely followed a normal distribution with no evidence of a ceiling effect. In adjusted regression models, COGTEL total and subcomponent scores were negatively associated with age and strongly positively with higher education, whereas the association with sex was less consistent. Conclusions: The results suggest that the COGTEL can readily be administered to large study populations and produces plausible and informative results. Education should be considered in all investigations using this instrument and requires further in-depth analyses. Future studies will need to elucidate its associations with risk factors and its prognostic potential for cognitive decline and dementia. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
63

A Study of Partitioning and Parallel UDF Execution with the SAP HANA Database

Große, Philipp, May, Norman, Lehner, Wolfgang 08 July 2014 (has links)
Large-scale data analysis relies on custom code both for preparing the data for analysis as well as for the core analysis algorithms. The map-reduce framework offers a simple model to parallelize custom code, but it does not integrate well with relational databases. Likewise, the literature on optimizing queries in relational databases has largely ignored user-defined functions (UDFs). In this paper, we discuss annotations for user-defined functions that facilitate optimizations that both consider relational operators and UDFs. We believe this to be the superior approach compared to just linking map-reduce evaluation to a relational database because it enables a broader range of optimizations. In this paper we focus on optimizations that enable the parallel execution of relational operators and UDFs for a number of typical patterns. A study on real-world data investigates the opportunities for parallelization of complex data flows containing both relational operators and UDFs.
64

Computational Design of Nanomaterials

Gutierrez Laliga, Rafael 15 December 2017 (has links)
The development of materials with tailored functionalities and with continuously shrinking linear dimensions towards (and below) the nanoscale is not only going to revolutionize state of the art fabrication technologies, but also the computational methodologies used to model the materials properties. Specifically, atomistic methodologies are becoming increasingly relevant in the field of materials science as a fundamental tool in gaining understanding on as well as for pre-designing (in silico material design) the behavior of nanoscale materials in response to external stimuli. The major long-term goal of atomistic modelling is to obtain structure-function relationships at the nanoscale, i.e. to correlate a definite response of a given physical system with its specific atomic conformation and ultimately, with its chemical composition and electronic structure. This has clearly its pendant in the development of bottom-up fabrication technologies, which also require a detailed control and fine tuning of physical and chemical properties at sub-nanometer and nanometer length scales. The current work provides an overview of different applications of atomistic approaches to the study of nanoscale materials. We illustrate how the use of first-principle based electronic structure methodologies, quantum mechanical based molecular dynamics, and appropriate methods to model the electrical and thermal response of nanoscale materials, provides a solid starting point to shed light on the way such systems can be manipulated to control their electrical, mechanical, or thermal behavior. Thus, some typical topics addressed here include the interplay between mechanical and electronic degrees of freedom in carbon based nanoscale materials with potential relevance for designing nanoscale switches, thermoelectric properties at the single-molecule level and their control via specific chemical functionalization, and electrical and spin-dependent properties in biomaterials. We will further show how phenomenological models can be efficiently applied to get a first insight in the behavior of complex nanoscale systems, for which first principle electronic structure calculations become computationally expensive. This will become especially clear in the case of biomolecular systems and organic semiconductors.
65

Understanding age-related prospective memory performance: The role of cognitive, motivational and emotional mechanisms associated with age differences in the delayed execution of intended actions

Schnitzspahn, Katharina 17 August 2011 (has links)
A pervasive real-world memory task is remembering to carry out intended activities at appropriate moments in the future, such as remembering to call one’s mother after returning from work or to hand a message to a colleague when seeing him in the office on the next morning. Such types of tasks are termed prospective memory (PM) tasks (Einstein & McDaniel, 1996). PM has been identified as one of the most frequent everyday memory challenges (e.g., Maylor, 1990), particularly in old age (McDaniel, Einstein, & Rendell, 2008) and an intact PM is considered to be crucial for the maintenance of independent living (Kliegel & Martin, 2003). Therefore, many researchers have focused on the exploration of possible age differences in PM. While age-related deficits were found in standard lab-based PM tasks, age-related benefits occured in naturalistic tasks that are carried out in participants’ everyday lives. This surprising pattern has been called the age-PM-paradox (Rendell & Craik, 2000). It has been supported by a meta-analysis comparing PM age effects found in studies that focused either on lab-based or on naturalistic PM tasks (Henry, MacLeod, Phillips, & Crawford, 2004). However, the mechanisms which are critical in determining the direction of age effects remain poorly delineated. Thus, the overall aim of the research programme presented in the present thesis was to investigate the age-PM-paradox as well as potential cognitive, motivational and emotional mechanisms and processes associated with age-related PM performance. For that purpose, three experimental studies were conducted testing adult age effects in different PM task settings with different task material. Furthermore, several possible underlying mechanisms suggested by the literature on age effects in PM were measured and/ or varied experimentally. The first aim of Study 1 was to cross-validate the age-PM-paradox within a single sample. The second aim was to empirically explore the relative importance of four recently proposed factors (motivation, metacognitive awareness, activity absorption, and control over the task) that may be associated with the direction of age effects inside and outside of the laboratory. For that purpose, 20 young and 20 older adults performed a lab-based and a naturalistic PM task, which were similar in structure and demand. The level of control was experimentally manipulated in both task settings. The remaining possibly influencing factors (motivation, metacognitive awareness, and activity absorption) were assessed via questionnaires in the laboratory and with a daily diary in the field. First, analysing mean level age differences, the paradox was confirmed. Second, exploring possible correlates of the paradox revealed that the level of daily activity absorption (i.e., everyday stress) was the most important mechanism in naturalistic PM performance. Further, high motivation and good metacognitive awareness were associated with age benefits in PM performance in the naturalistic task, while high ongoing activity absorption and low control over the PM cue were related to deficits in lab-based tasks. Thus, Study 1 confirmed the age-PM-paradox within one sample and with carefully matched lab-based and naturalistic tasks. In addition, the results indicate that the relative importance of the suggested factors may vary as a function of setting. While cognitive factors were most influential in the laboratory, motivational and knowledge-based factors were associated with high PM performance in the naturalistic task. The strong association between PM performance in the field and everyday stress highlights the need for future studies exploring the mechanisms underlying this effect. Results from Study 1 suggest that cognitive resources are most influential for PM age effects in the laboratory. Yet, it is not clear, which specific cognitive resources are needed for successful PM performance and if these processes differ between young and older adults. Thus, Study 2 explored the role of executive functions (i.e. shifting, updating and inhibition) as possible developmental mechanisms associated with PM age effects. 170 young and 110 older adults performed a battery of cognitive tests including measures of PM, shifting, updating, inhibition, working memory and speed. A comprehensive set of statistical approaches (e.g. median analyses, structural equation modelling) was used to analyze the possible cognitive correlates in predicting PM performance. First, age effects were confirmed in PM and also obtained in measures of executive control. Moreover, the facets of executive control differently predicted PM performance. Specifically, shifting was the strongest predictor of PM performance in young and older adults as well as for explaining age differences in PM. Thus, Study 2 clarified the role of different facets of controlled attention in age effects in PM and bears important conceptual implications: The results suggest that executive functions are important developmental mechanisms of PM across adulthood beyond working memory and speed. Specifically, shifting appeared to be an essential aspect of cognitive control involved in age-related PM performance. Moreover, examining PM as a latent construct confirmed the convergent and discriminant validity of PM. This demonstrates PM as a separate cognitive construct and suggests that PM is related to, but not identical with, executive control. Study 3 was set out to explore if the amount of cognitive resources needed to successfully perform a PM task in the laboratory can be influenced by the emotionality of the task material. First studies suggested that emotional task material may enhance PM performance in young and older adults by heightening the salience of the task and thereby reducing the need for controlled attention. However, the extent and mechanisms of this effect are still under debate. Therefore, Study 3 explored possible differential effects of PM target cue valence on PM age effects. For that purpose, 45 young and 41 older adults performed a PM task in which emotional valence of the PM cue was manipulated (positive, negative, neutral). Results revealed an interaction indicating that age differences were smaller in both emotional valence conditions compared to the neutral condition. This finding supports an emotionally enhanced memory effect in PM, but only for the older adults as PM performance in young adults was not affected by cue valence. From a conceptual perspective, the results from Study 3 may also contribute to the explanation of the age-PM-paradox, as they suggest that the neutral material usually applied in lab-based studies might overestimate PM age effects. In summary, the present thesis makes an important contribution to the ongoing conceptual debate concerning adult age effects in PM performance assessed in the laboratory versus participants’ everyday lives. Results strongly suggest that mostly different variables may be crucial for understanding PM age deficits in the laboratory and age benefits in naturalistic PM tasks. Successful PM performance in the laboratory seems to require high levels of cognitive resources. The present results suggest that shifting ability is especially relevant in this respect. On a task level the emotionality of the material seems to influence the required amount of cognitive resources as it reduced PM age effects. Everyday stress seems to be particularly important for successful PM performance in the field. Thus, possible future studies should specify the relation between stress and PM as outlined in the general discussion.
66

Understanding Quadratic Functions Using Real World Problems and IT

Karim, Nakhshin A. 02 May 2012 (has links)
The concept of function is crucial to a great extent in modern mathematics and is considered a major barrier to many mathematics students. Students have difficulty interpreting information related to functions in general, and quadratic functions in particular. Quadratic Function is one of the topics which are covered in a course which is compulsory for a large number of students in the General Education Program of Zayed University. This program leads to different majors, including Mathematics Education, Business, Information Technology, and other majors. The challenge in teaching Quadratic Function in a course like this is mostly based on the fact that many students think that Quadratic Function is a difficult topic to understand and learn, and some teachers would agree with them that it is difficult to teach. In this paper, I demonstrate real world problems aimed to improve the students understanding of Quadratic Functions; life problems on this topic support developing student’s knowledge, critical thinking, quantitative reasoning, and analytical skills. This paper also includes examples of the techniques used with graphing of quadratic function, the algebra, and inverses of the same function. International move to improve mathematics curriculum have supported new goals for student’s learning which highlights problem solving skills, reasoning, ability to work in groups and individually, and use of technology. Knowing that information technology plays considerable role in achieving the above goals, teaching students the concept of Quadratic Functions can be smoothly achieved by using Information Technology in solving real world problems.
67

TO TEACH COMBINATORICS, USING SELECTED PROBLEMS

Modan, Laurentiu 07 May 2012 (has links)
In 1972, professor Grigore Moisil, the most famous Romanian academician for Mathematics, said about Combinatorics, that it is “an opportunity of a renewed gladness”, because “each problem in the domain asks for its solving, an expenditure without any economy of the human intelligence”. More, the research methods, used in Combinatorics, are different from a problem to the other! This is the explanation for the existence of my actual paper, in which I propose to teach Combinatorics, using selected problems. MS classification: 05A05, 97D50.
68

Ungeordnete Zahlpartitionen mit k Parts, ihre 2^(k - 1) Typen und ihre typspezifischen erzeugenden Funktionen

Lösch, Manfred 06 December 2012 (has links)
Jede ungeordnete Zahlpartition mit k Parts (k-Partiton) hat einen Typ, der mittels einer geordneten Partition von k definiert werden kann. Es können somit 2^(k - 1) Typen definiert werden. Pro Typ gibt es eine eindeutig nummerierbare erzeugende Funktion der geschlossenen Form. Mit Rekursionen können diese Funktionen in (unendlich lange) Potenzreihen expandiert werden. Mit diesen erzeugenden Funktionen lassen sich Bijektionen zwischen den Partitionsmengen verschiedener Typen aufspüren.:1. Kurze Vorbetrachtung 2. Typen der ungeordneten k-Partitionen 3. Konstruktion der GF (generating function) des allgemeinen Typs 4. Nummerierung der konstruierten GF 5. Weitere Analysen zur konstruierten GF 6. Die konjugierten der typspezifischen k-Partitionen 7. Vereinfachte GF-Symbolik 8. Eine programmierbare Basis-GF 9. Dekomposition von Q(x, k) in typspezifische GF''s 10. Rekursives Expandieren typspezifischer GF''s 11. GF-Zerlegungen und Bijektionen 12. Zahlen, die in k-Partitionen aller Typen zerlegbar sind 13. Referenzen
69

Referenzielle Kohärenz im Erstspracherwerb: Untersuchungen zur Verarbeitung und Produktion anaphorischer Referenz

Lehmkuhle, Ina 13 May 2022 (has links)
Die Bezugnahme auf bereits in den Diskurs eingeführte Referenten durch Anaphern stellt ein zentrales Mittel zur Etablierung referenzieller Kohärenz dar. Der Gebrauch anaphorischer Referenzausdrücke hängt dabei mit dem Grad der Zugänglichkeit der mentalen Repräsentation eines Diskursreferenten zusammen: Referenzausdrücke wie Pronomen spiegeln beispielsweise einen hohen Zugänglichkeitsgrad wider, wohingegen Referenzausdrücke wie Nominalphrasen und Eigennamen einen niedrigeren Zugänglichkeitsgrad signalisieren (u.a. Ariel, 1990). Der relative Zugänglichkeitsgrad von Diskursreferenten wird dabei von verschiedenen Zugänglichkeitsfaktoren auf unterschiedlichen sprachlichen Ebenen beeinflusst (für einen Überblick: Arnold, 2010). Diese Dissertation beschäftigt sich mit dem Erwerb referenzieller Kohärenz durch deutschsprachige Kinder. Dabei geht es sowohl um die Verarbeitung als auch um die Produktion anaphorischer Referenzausdrücke. Zum einen stellt sich hierbei die Frage, inwiefern Kinder in der Lage sind, anaphorische Referenzausdrücke als Hinweis auf den Grad der Zugänglichkeit von Diskursreferenten online zu verarbeiten und offline zu interpretieren. Zum anderen wird untersucht, inwiefern Kinder beim Gebrauch anaphorischer Referenzausdrücke den relativen Zugänglichkeitsgrad von Diskursreferenten in narrativen Textproduktionen berücksichtigen. Um zu überprüfen, auf welche Weise sich Kinder hierbei von Erwachsenen unterscheiden, werden die Ergebnisse der kindlichen Gruppe jeweils mit denen einer erwachsenen Kontrollgruppe verglichen. Die Ergebnisse der Untersuchungen in dieser Arbeit zeigen, dass deutschsprachige Kinder sowohl bei der Verarbeitung als auch bei der Produktion von anaphorischen Referenzausdrücken sensibel auf den relativen Zugänglichkeitsgrad von Diskursreferenten reagieren: Drei- bis vierjährige Kinder bevorzugen bei der Online-Verarbeitung Personalpronomen gegenüber wiederholten Eigennamen, wenn sich diese auf höchst zugängliche Diskursreferenten beziehen (Experiment 1, Eyetracking). Dies wird als Hinweis darauf gewertet, dass sie verstehen, dass sich gewisse Ausdrücke besser als andere dazu eignen, auf höchst zugängliche Diskursreferenten zu verweisen. Zudem berücksichtigen neun- bis zehnjährige Kinder bei der Produktion anaphorischer Referenzausdrücke in narrativen Textproduktionen lokale und globale Zugänglichkeitsfaktoren (Studie, Bildergeschichte). Als lokaler Zugänglichkeitsfaktor wird hier die referenzielle Funktion (Erhalt vs. Wiederaufnahme) betrachtet; der Charaktertyp (Hauptcharakter vs. Nebencharakter) repräsentiert hingegen einen globalen Zugänglichkeitsfaktor (Vogels, 2014). In Übereinstimmung mit den Präferenzen Erwachsener benutzen die Kinder überwiegend Pronomen zum Erhalt und Nominalphrasen zur Wiederaufnahme von Diskursreferenten. Ein Unterschied zu den Erwachsenen besteht jedoch im Hinblick auf den globalen Zugänglichkeitsfaktor des Charaktertyps: Anders als die Erwachsenen verweisen die Kinder vorzugsweise mit Pronomen auf Hauptcharaktere und mit Nominalphrasen auf Nebencharaktere. Erwachsene scheinen den globalen Zugänglichkeitsfaktor des Charaktertyps hingegen erst dann zu berücksichtigen, wenn lokale Diskursanforderungen erfüllt sind. Dies legt nahe, dass Kinder Zugänglichkeitsfaktoren zum Teil anders gewichten als Erwachsene. Für eine ähnliche Interpretation spricht auch das Verhalten acht- bis neunjähriger Kinder bei der Online-Verarbeitung von Personalpronomen und definiten Nominalphrasen (Experiment 2, Eyetracking). Während die Erwachsenen Personalpronomen gegenüber Nominalphrasen bevorzugen, wenn sich diese in der Funktion des Topikerhalts auf höchst zugängliche Diskursreferenten beziehen, zeigen die Kinder keinen Unterschied in ihrem Blickverhalten in Bezug auf diese beiden referenziellen Ausdrucksformen. Dies spricht dafür, dass die Kinder die informationsstrukturelle Funktion dieser beiden Referenzausdrücke im Gegensatz zu den Erwachsenen unberücksichtigt lassen. Obwohl Kinder bei der Verarbeitung und Produktion anaphorischer Referenzausdrücke bereits vielfach den relativen Zugänglichkeitsgrad von Diskursreferenten berücksichtigen, scheint der Erwerb anaphorischer Referenz auch noch am Ende der Grundschule nicht abgeschlossen zu sein.
70

CSP dichotomy for ω-categorical monadically stable structures

Bodor, Bertalan 18 January 2022 (has links)
The constraint satisfaction problem (CSP) over a structure A with a finite relational signature, denoted by CSP(A), is the problem of deciding whether a given finite structure B with the same signature as A has a homomorphism to A. Using concepts and techniques from universal algebra, Bulatov and Zhuk proved independently that if A is finite, then the CSP over A is always in P or NP-complete. Following this result, it is a natural question to ask when and how this dichotomy can be generalized for infinite structures. The infinite-domain CSP dichotomy conjecture (originally formulated by Bodirsky and Pinsker [BPP14]) states that the same complexity dichotomy holds for first-order reducts of finitely bounded homogeneous structures. This conjecture has been solved for many special classes of structures. In this thesis we are developing new techniques involving canonical polymorphisms to attack this conjecture. Using these techniques we prove a new CSP dichotomy result, namely we show that the CSP over every finitely related ω-categorical monadically stable structure is in P or NP-complete.

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