Rozprawy doktorskie na temat „Birge”

Ultraviolet (UV) spectra obtained from Earth's dayglow contain important information for understanding the thermosphere, and the N2 Lyman-Birge-Hopfield (LBH) bands are possibly the most useful emission. To be useful, a thorough understanding of how the LBH band emission varies with altitude and latitude is essential to present and future use of this emission by space-based remote sensors. Excited by photoelectron impact on N2 leading to transitions from the a 1[Pi]g state to the ground state, the LBH emissions radiate between 1270 and 2400 A. In addition to being populated by electron impact excitation, the a 1[pi]g state is populated by radiative and collisional cascading from adjacent singlet states a' 1[sigma]-u, and w 1[delta]u (Eastes, 2000). Ultimately, the intensity is most dependent on low energy electron flux (Ajello and Shemansky, 1985; Meier, 1991) because that is where the electron impact scattering cross sections of the singlet states are the largest. This dissertation presents modeled LBH profiles produced using the Intrasystem Cascade Excitation (ICE) model (Eastes, 2000) with photoelectron fluxes calculated using the Continuous Slowing Down (CSD) model (Jasperse, 1976). Both of these models implement the Mass Spectrometer and Incoherent Scatter (MSIS) to model an atmosphere. Modeled emissions are compared against observations by the High resolution Ionospheric and Thermospheric Spectrograph (HITS) on the Advanced Research and Global Observation Satellite (ARGOS). This dissertation will investigate the LBH emissions in detail and ultimately use them for remote sensing of thermospheric temperatures.
Ph.D.
Department of Physics
Sciences
Physics PhD

Thesis (M.F.A.)--Georgia State University, 2008.
Title from title page (Digital Archive@GSU, viewed July 6, 2010) Constance Thalken, committee chair; Sheldon Schiffer, Nancy Floyd, committee members. Includes bibliographical references (p. 35).

Binge is a multi-media installation consisting of dangling IV bags looming over a large table of food. Monitors on the table show live online chats about thinness, depression and eating disorders. On the rear wall, interview footage describing the gruesome experiences of the eating disorder sufferer intercut with the newest development of the disease, the online presence. The installation confronts the viewer with the horrible dualities of the disease: discipline and madness, reason and passion, and suffering and indulgence. The work references the philosophic mind/body struggle as well as the grim reality of these afflicted young women.

Binge-eating disorder (BED) was first included as its own diagnostic entity in the Fifth Edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) within the Feeding and Eating Disorders section.1 BED’s hallmark feature is recurrent binge eating, involving the consumption of an amount of food that is definitively larger than what others would eat under comparable circumstances within a certain time, associated with a feeling of loss of control over eating. Diagnosis of BED according to DSM-5 (307.59) requires this objective binge eating to occur at least once per week over 3 months. In contrast to binge eating in bulimia nervosa, binge eating in BED occurs without regular inappropriate compensatory behaviors aimed at preventing weight gain, such as self-induced vomiting, fasting, or laxative misuse. Binge eating in BED is further characterized by behavioral abnormalities, such as eating rapidly or until feeling uncomfortably full, and results in marked distress.

Psychology
Ph.D.
The well-documented relationship between alcohol use and affective distress can be destructive, in many cases leading to negative physiological, social, and legal consequences. Binge drinking, defined as a pattern of drinking that brings blood alcohol concentration levels to 0.08 g/dL, typically reached after drinking more than 4 (for women) or 5 (for men) standard drinks in under two hours, is an increasingly popular activity, particularly among young people, and rates of binge drinking spike around the same time lifelong patterns of alcohol abuse are being established. Given the prominence of negative affect and associated constructs (i.e., repetitive negative thought, intolerance of uncertainty, anxiety sensitivity, self-efficacy) in models of alcohol use, anxiety, and mood disorders, the present study examines the predictors and consequences of negative affect and associated constructs the day after binge drinking. Our primary aims were: (a) to determine the prevalence of negative affect the day after binge drinking in a large, undergraduate sample, and (b) to examine differences in negative affect, post-event processing, and negative perceived self-efficacy between individuals on days following binge drinking as compared to days following abstinence and to assess whether neuroticism moderated these differences. Secondary aims included examining predictors of situational avoidance, changes in alcohol use and negative affect, and psychological factors associated with neuroticism and increases in negative affect (i.e., alcohol-induced memory losses and intolerance of uncertainty, physical hangover symptoms and anxiety sensitivity). We hypothesized that types of negative affect (e.g., anxiety, depression, guilt) would be reported by 5% to 25% of the sample and that individuals in the binge group would report higher levels of state negative affect, post- event processing, and negative perceived self-efficacy in academic, social, and coping domains than individuals in the abstinence group. Further, we predicted that higher levels of neuroticism would be associated with higher levels of the outcome variables. Neuroticism was expected to moderate the main effect of group such that neuroticism would have a greater effect in the binge group than in the abstinence group. To these ends, the study was conducted in two parts: first, prevalence of negative affect the day after binge drinking was assessed in a large, undergraduate sample (N = 808). Then, a subsample (n = 139) was recruited to participate in a longitudinal, quasi- experimental examination in which participants were assessed at three time points: baseline, the day following either a night of binge drinking or a night of abstinence, and two weeks following their second assessment. In line with hypotheses, types of negative affect ranged in prevlance from 22.8% of the sample (Apathy) to 1.0% of the sample (Suicidal thoughts). In addition, negative affect, post-event processing, and negative perceived self-efficacy in academic, social, and coping domains were higher on days following binge drinking compared to days following abstinence. Of note, neuroticism did not moderate any of these relationships. Additional results and implications are discussed.
Temple University--Theses

Binge drinking has become common among adolescents. Binge drinking has many negative consequences and can lead to many health problems. The purpose of the present study was to explore the related factors persuading adolescents to binge drink. Several risk factors were examined in the study using a survey from adolescents between the ages of 12 and 17. Some of the risk factors examined included: parental marital status, adult supervision, missed school days, and emotional anguish. The results showed that the risk factors greatly influenced alcohol consumption among adolescents and binge drinking. The study was important to advance the literature on the subject of binge drinking among adolescents by providing greater knowledge of the potential risk factors and drinking problem.

Eating disorders (EDs) are complex psychiatric illnesses involving genetic, environmental, cognitive and neurobiological factors. Recurrent, compulsive binge eating episodes (BEs) are a debilitating core symptom of bulimia nervosa (BN), binge eating disorder (BED), anorexia nervosa binge-purge subtype (AN-BP) and are a common feature of other specified feeding and eating disorder (OSFED). Neuroimaging techniques, particularly functional magnetic resonance imaging (fMRI), and research using fMRI in EDs, have both expanded significantly in recent decades. However, neuroimaging studies in BN and BED are significantly fewer relative to anorexia nervosa (AN). The use of disorder-relevant stimuli during neuroimaging, particularly food due to the role it plays in these illnesses, is a key area of interest, as understanding how the neural response to food differs in EDs can help to inform new, targeted treatment strategies. The aim of this thesis is to improve understanding of the differences in neural response between individuals with BN and BED compared to healthy controls (HCs) to low and high energy food stimuli. The thesis consists of a literature review and three peer-reviewed studies. The systematic review provides a comprehensive overview of the findings of 32 neuroimaging studies with BN and BED participants; the two empirical studies comprise a large fMRI study, with the first study examining neural responses of individuals with BN or BED to low energy foods compared to neutral items; the second empirical study with the same cohort investigated the profile of neural responses towards high energy food images. It is hoped that the findings of the studies increase understanding of the neural differences that may underlie compulsive binge eating in those with BN and BED and inform improvements in evidence-based treatment options.

There is a high prevalence rate of women who have alcohol problems and a co-morbid eating disorder, particularly Bulimia Nervosa. Few studies have attempted to examine the mechanisms underlying this relationship. The notion of self-control is well documented in the literature and is central to disorders of 1) eating and 2) drinking. However, within each of these disorders, no single definition of self-control exists. The aim of the current study was to develop an understanding of the meaning of self-control, as it relates to women with binge eating and binge drinking problems. Semi-structured interviews were conducted with six women who were in contact either with an eating disorder service or an alcohol service. The interviews were analysed using the qualitative methodology of Grounded Theory, which also informed the data collection process. A process model of self-control was developed, to account for the transition from having a perceived need for self-control to a continued struggle for self-control. The notions of self-control were found to be fuelled with contradictions and misapprehensions and therefore a core category of 'Illusion' was described. The findings were also related to existing theoretical models, with new themes not previously identified in the literature being highlighted. The research has important implications at a service, theoretical and clinical level.

The aim of this thesis is to explore the process of treatment seeking for eating disorders (EDs). EDs are frequently associated with psychological distress and poor quality of life, and it is widely recognised that there is a large proportion of individuals with EDs who are not accessing appropriate specialist treatment. This is concerning given that delays in treatment have been associated with poorer outcomes. A review of the literature regarding the experience of treatment seeking for an ED was carried out, this included: anorexia nervosa (AN); bulimia nervosa (BN); eating disorder not otherwise specified (EDNOS); binge eating disorder (BED); and sub-threshold eating difficulties. This review highlighted five themes across the papers; social stereotypes and norms; external factors; client (internal) factors; interpersonal factors; and gender. Critical review of eight papers found inconsistencies in the methods used for screening EDs and also large heterogeneity in the ED samples used. These methodological limitations should be taken into account when considering the findings. Paucity in research focusing specifically on treatment seeking for BED was highlighted. In response to this gap in the literature, Interpretative Phenomenological Analysis was used to explore the lived experience of people treatment seeking for BED. This analysis resulted in the following themes: the self as a barrier; the overlooked eating disorder; factors contributing to treatment seeking and disclosure; and making sense of BED. These findings are integral to engaging individuals with BED in services and ensuring that this often overlooked group are not left without appropriate treatment. These themes are considered in relation to existing theory; together with clinical implications and directions for future research. A reflective commentary considers personal reflections of completing the research; the influence of society on weight and shape; EDs and gender; and the controversial topic of psychiatric diagnosis.

Thesis (Ph.D.)--Kent State University, 2007.
Title from PDF t.p. (viewed March 28, 2008). Advisor: Janis H. Crowther. Keywords: binge eating, eating behavior, African American / Black, emotion regulation. Includes survey instrument. Includes bibliographical references (p. 94-107).

This research analyses a binge drinking night out of women aged 25-55. The research method is a thematically structured phenomenological analysis utilising Structured Existential Analysis (SEA) (Deurzen 2010) and Fractions of the Lifeworld (Ashworth 2003) as overlapping heuristic devices. The thematic structure allows a strong narrative flow, which ensures that the voices of co-researchers are maintained throughout. These voices are analysed with SEA, which generative process unveils a greater number of sub themes and an increased complexity that is then analysed using the Fractions of the Lifeworld heuristic. Emotional movement across the night out is tracked and many interwoven themes emerge including gender, sexuality, resistance, freedom, self worth and power. The night out is found to have a ritual structure of time that allows co-researchers a temporary transcendence of their pallid mood as a satiated tedium. The night out is in turn experienced as satiated fullness and is transcended by the release of the next day and the return to work. It is suggested that this ontological movement of the emotions is a possible key-underpinning factor in the initiation of the process of ritual, addiction and of all motivational movement.

Textilbewehrter Beton ist ein Verbundwerkstoff aus einer Feinbetonmatrix und einer kraftgerichteten textilen Bewehrung aus ARGlasfaser- oder Carbongelegen. Die heterogene Materialstruktur der textilen Bewehrung im Verbundbaustoff Textilbeton führt zu einem komplexen Tragverhalten mit einer Vielzahl sich zum Teil gegenseitig in ihrer Wirkung beeinflussender Effekte. Aufgrund der abweichenden Material- und Verbundeigenschaften können für die Bemessung von textilbewehrten Betonbauteilen die aus dem Stahlbetonbau bekannten Modelle nicht pauschal übertragen werden. In diesem Beitrag werden die wesentlichen Erkenntnisse experimenteller Untersuchungen von textilbewehrten Elementen unter Biege- und Querkraftbeanspruchung dargestellt, die Mechanismen des Tragverhaltens beschrieben und empirisch abgeleitete Berechnungsmodelle vorgestellt.

Nástup VOD přinesl novou formu spotřeby obsahu: binge-watching. Tato práce zkoumá, jak tento posun začal ovlivňovat scénář seriálů, které jsou koncipovány tak, aby byly zhlédnuty hned po sobě (binge-watched).

In my thesis I was trying to analize Nuri Bilge Ceylan´s feature films in chronological order, focusing on the possibilities and limitations of non-narrative and purely cinematic ways of expression - like the mis-en scené, editing, framing or creative sound editing. I wrote about all the five movies of the famous Turkish director, which were recently awarded with numerous awards in the most important film festivals: "Kasaba" ( "The Small town" ), "Mayis sikintisi" ( "Clouds of May" ), "Uzak" ( "Distant" ), "Iklimler" ( "Climates" ) a "Üç maymun" ( "Three Monkeys" ). In my analysis I focused on strictly formal film sequences - but I also tried to take a closer look at the coexistence and influence of the dead time sequences on the elements of dramatic narrative in these movies.

Rates of pediatric obesity in America are reaching epidemic proportions. Studies using both community and treatment-seeking samples of obese adolescents indicate that a subset engage in binge eating behaviors. This study investigated the prevalence and severity of binge eating behaviors among 86 primarily African American 11 to 17 year old adolescents seeking outpatient treatment for obesity. This study also examined the associations of stressful experiences (specifically, weight-related teasing, trauma, and daily hassles) with binge eating, as well as potential mediators and moderators of these relationships. Twenty-eight percent of the sample reported at least one episode of binge eating in the past two weeks and there were no ethnic or gender differences in rates of binge eating, nor in any other measures of eating related pathology. None of the forms of stress were associated with binge eating. However, weight-related teasing and trauma were associated with overall eating pathology. Therefore, the global measure of eating pathology was used as the dependent variable in the subsequent analysis.Although it was hypothesized that depressive symptoms would mediate the relationship between stressful experiences and disordered eating, this was not the case. Instead, the upset feelings about being teased mediated the relationship between depressive symptoms and disordered eating. It was also hypothesized that self-esteem and ethnic identity would moderate the relationships between stress and disordered eating. Self-esteem was not a significant moderator, but ethnic identity was among the European American participants only. Interpretation of the moderating role of ethnic identity revealed that European American participants with stronger ethnic identity were more likely to report disordered eating when they had also experienced teasing, trauma, and daily hassles. This result is interpreted using sociocultural theories which posit that the European American culture places individuals at more risk for disordered eating because of the emphasis placed on a thin body image ideal. Therefore, when European American obese adolescents identify highly with their ethnicity, they may be at more risk for developing disordered eating when they have also experienced other risk factors such as stressful life experiences. Future research should attempt to replicate these findings using a longitudinal approach.

Binge eating disorder (BED) is the most prevalent of all eating disorders and is characterized by recurrent episodes of eating a large amount of food in the absence of control. There have been various kinds of research of BED, but the phenomenon remains poorly understood. This thesis reviews the results of research on BED to provide a synthetic view of the current general understanding on BED, as well as the neural correlates of the disorder and treatments. Research has so far identified several risk factors that may underlie the onset and maintenance of the disorder, such as emotion regulation deficits and body shape and weight concerns. However, neuroscientific research suggests that BED may characterize as an impulsive/compulsive disorder, with altered reward sensitivity and increased attentional biases towards food cues, as well as cognitive dysfunctions due to alterations in prefrontal, insular, and orbitofrontal cortices and the striatum. The same alterations as in addictive disorders. Genetic and animal studies have found changes in dopaminergic and opioidergic systems, which may contribute to the severities of the disorder. Research investigating neuroimaging and neuromodulation approaches as neural treatment, suggests that these are innovative tools that may modulate food-related reward processes and thereby suppress the binges. In order to predict treatment outcomes of BED, future studies need to further examine emotion regulation and the genetics of BED, the altered neurocircuitry of the disorder, as well as the role of neurotransmission networks relatedness to binge eating behavior.

This thesis explored the feasibility and efficacy of individual emotion-focused therapy for binge-eating disorder, and the role of beliefs about emotions and emotional expressivity as potential mechanisms of change. The unique findings of this research will assist clinicians and patients by providing another treatment option for binge-eating disorder, which is important given mounting evidence of the comparatively high prevalence and clinical significance, and the paucity of proven effective treatment approaches for this condition compared to other eating disorders such as anorexia nervosa and bulimia nervosa.

The subject of this thesis study is Ç
ukur Hamam, one of the remarkable edifices in Birgi town in Ö
demis district of Izmir. The aim of the study is to create a restoration project for Ç
ukur Hamam to provide its survival by integrating its neighbourhood to the social life of the city. During the study the edifice and its periphery was documented carefully by using 3D Laser Scanner. In the historical and comparative study the original status of the edifice was researched. With respect to the data gathered from the studies, a restoration project which includes the intervention decisions for the conservation of the physical condition and authentic elements of the edifice.

The central aim of the present study was to examine the role of expectancies in binge eating behavior. Two distinct statistical techniques were used to accomplish this goal. First, regression analyses were conducted using variables previously identified in the literature, as well as eating expectancies as measured by the Eating Expectancy Inventory (EEI). For both females and males, regression equations including expectancies accounted for a substantial portion of the variance in binge eating behavior. Second, memory modeling techniques were used to model the probable organization of eating expectancies. Memory modeling of hypothetical expectancy networks has lead to successful interventions in alcohol use, and preliminary work in eating revealed a fundamental difference in the way that individuals with high levels of pathology activate and store eating related messages. In the present study, Individual Differences Scaling was used to model the two-dimensional organization of an eating expectancy memory network in relation to binge eating. INDSCAL weights indicated that participants with higher levels of binge eating placed more emphasis on the positive-negative dimension, and examination of group means revealed that high binge eaters expected more change in mood in response to eating. All findings are discussed in terms of implications for enhancing assessment, treatment, and prevention strategies.
Ph.D.
Department of Psychology
Sciences
Psychology

This study examined how attentional sub-processes contribute to binge-eating. Dense-array EEG and a version of the canonical attentional blink task were used to ascertain the neural correlates underlying the attentional sub-processes that comprise the Posner model of attention (alerting, orienting, and executive control) and how attentional activation differs for binge-eaters vs. non-binge eaters. Furthermore, we examined a number of the event-related potentials (ERP), including P2 activation, which has been linked with orientating of attention, and N2 activation which has been linked with attentional conflict. We found decreased P2 activation for binge-eaters, in the negative condition, for incorrect target 2 (T2) detection trials. We also found more N2 activation for binge-eaters than non-binge eaters, in negative trials when T2 was not detected. This pattern of results suggest that binge-eaters showed deficiencies in allocating attention to stimuli that followed negative images; this attention deficiency may be a key factor for binge-eating behavior.

Binge-watching, the act of watching large amounts of television at a time, has become a popular phenomenon internationally; however, it has yet to be sufficiently defined. In order to define binge-watching, data was collected on specific watching instances from 216 undergraduate students at a large research university. Hierarchical and k-means cluster analyses were conducted in Phase I to empirically determine how binge-watching should be defined. In Phase II, that definition was tested by correlating the number of instances of binge-watching in a one-week period, collected by seven days of daily diary logs, with several theoretically related measures including body mass index, dissociative tendencies, psychological distress, compulsion to watch, boredom proneness, and escapism through watching. The data-driven definition was found to be that eight hours or more of continuous watching was binge-watching, while anything less than that was not. In Phase II, the frequency of binge-watching through the seven-day period was calculated based on that new definition. The frequency of binge-watching was positively correlated with body mass index and dissociative tendencies with statistical significance at the alpha = .05 level. Compulsion to watch was not statistically significant; however, there was a positive correlation. These findings indicate that the proposed data-driven definition has concurrent validity. Psychological distress, boredom proneness, and escapism through watching were not statistically significantly related to binge-watching frequency, nor did the effect sizes indicate a correlation may exist. Potential reasons for these results are discussed. The definition found in this study will be helpful to other researchers as research into binge-watching continues to grow.

The current quantitative study attempted to understand, identify and examine four aspects of the viewing behavior; binge watching. Those aspects were binge watching characteristics, binge watching motivations and people’s perceptions of binge watching, as well as exploring the relationships between binge watching and gender. The study found that people would usually binge watch alone between 3-5 episodes in one session, and they would spend six hours binge watching on weekends. Moreover, catching up on missed episodes was the only positive significant motivation the study found. The study found people perceived binge watching as a satisfying activity that made them feel in control, which would not cause anxiety, addiction, or isolation even though it was unproductive and time-wasting behavior. The study found some differences between men and women. Women binge watched dramas and were motivated by catching up on missed episodes. Women tended to perceive binge watching as unproductive behavior. Men were more likely to repeat binge watching after they had already finished doing so.

Background Binge eating is often co-morbid with obesity. There is no widely accepted theoretical model for binge eating, this has treatment implications. Research has highlighted the role of metacognitions in psychopathology, including eating disorders. However, metacognitions in obesity and binge eating have not yet been researched. The self-regulatory executive functioning model (S-REF; Wells & Matthews, 1994, 1996) conceptualises the role of metacognition in the aetiology and maintenance of psychological disturbance. This exploratory study aimed to explore metacognition in people with obesity and binge eating, and people with obesity without binge eating. Design A clinical sample of ten participants, five with obesity and binge eating, and five with obesity without binge eating were recruited. A mixed-method design was utilised, with a dominant qualitative component. Participants were interviewed using the Metacognitive Profiling Interview and completed self-report measures to contextualise the results. Using template analysis the two groups were first analysed separately, and then compared to each other. Results Three main themes were identified; metacognitive judgements, metacognitive processes and thought control strategies. The binge-eating group reported experiencing greater and more problematic metacognitions, metacognitive processes and thought control strategies than the non binge-eating group. Conclusions The results build upon existing metacognitive research, indicating that metacognitions involved in the development and maintenance of binge eating in obesity are often very different from those involved in obesity without binge eating. This suggests the S-REF iii model may have relevance for binge eating in obesity. The study supports the idea that individuals with binge eating should be offered specialised treatment that is distinct from the treatment for obese non-binge eaters. Further research is needed to develop an empirically-tested disorder-specific model of binge eating.

- Ziele der Arbeit - Das primäre Ziel der vorliegenden Arbeit bestand in einer möglichst umfassenden Be-schreibung einzelner Entwicklungsstadien im Verjüngungszyklus von Betula pendula Roth. Dabei waren die lokalen Bestandes- und Standortsbedingungen im Untersuchungsgebiet in besonderer Weise zu berücksichtigen. Des Weiteren sollten Optionen zur waldbaulichen Integration der Sand-Birkenverjüngung in bestehende Behandlungskonzepte für in Auflösung befindliche Fichtenaltbestände aufgezeigt werden. - Untersuchungsgebiet - Der Tharandter Wald liegt im Freistaat Sachsen (50° 55’-50° 00’n. Br., 13° 25’-13° 35’ ö. L.) und umfasst eine Fläche von etwa 6.000 ha. Das von der Baumart Fichte dominierte Gebiet kolliner bis submontaner Höhenstufe (350 - 420 m ü. NN) wird der „Unteren Nordostab-dachung des Erzgebirges“ zugeordnet. Als Untersuchungsflächen wurden wechselfeuchte (wechselfrische) Standorte mittlerer Trophie gewählt, die von einschichtigen Fichtenbe-ständen in einem Alter von ≥ 80 Jahren bestockt waren. Einzeln bis truppweise eingemischte Samenbäume der Sand-Birke (B. pendula) bildeten eine Grundvoraussetzung für die Flächen-auswahl. - Methodisches Vorgehen - Das methodische Vorgehen konzentrierte sich auf die verjüngungsökologisch relevanten Entwicklungsstadien (fruktifizierender Samenbaum, Diaspore, Keimling, Sämling und eta-blierte Verjüngungspflanze) der Sand-Birke. Die Wachstumsparameter der vorhandenen Samenbäume wurden durch Untersuchungen zum Fruchtbehang unterlegt. Der mehrstufige Versuchsansatz zur Erfassung einzelner Verjüngungsstadien stützte sich auf Bestandesauf-nahmen, Gefäß- und Laborversuche. Erhebungen auf Bestandesebene erfassten die Diaspo-renausbreitung mithilfe von Samenfallen und dokumentierten die Keimlings- und Ver-jüngungsstadien von B. pendula auf entsprechend etablierten Aufnahmeplots (1 m x 1 m). Darüber hinaus umfassten die Aufnahmen Strahlungs- und Feuchtemessungen und die Charakterisierung der Bodenvegetation. Für die Einschätzung des mikrostandörtlichen Um-feldes wurden exemplarisch Bodendeckungsvarianten (Mineralboden, Nadelstreuauflage, Calamagrostis villosa CHAIX (GMEL.) und Deschampsia flexuosa L. (TRIN.)) ausgewählt, die als besonders repräsentativ für reine Fichtenbestände des Erzgebirges gelten. Für die räumliche Modellierung der Diasporen und Keimlinge auf Bestandesebene stand das Pro-gramm WALDSTAT (NÄTHER & WÄLDER 2003) zur Verfügung. Im Rahmen des Mitscherlich-Gefäßversuchs wurden gleichermaßen quantitative und qualitative Entwicklungen von Sand-Birkenkeimlingen und -sämlingen erhoben. Der Einfluss ausgewählter Bodendeckungs-varianten wurde in diesen Betrachtungen berücksichtigt. Neben zahlreichen Pflanzenpara-metern (Spross-, Blatt- und Wurzelentwicklung, Allokationen, Allometrien) war die kleinstandörtliche räumliche Verteilung dieser Verjüngungspflanzen von vorrangiger Be-deutung. Als Verteilungs- und Konkurrenzmaße auf Ebene des Mikrostandortes dienten Tessellationsmodelle, der Aggregationsindex nach CLARK & EVANS, der Gini-Koeffizient und das “Constant Yield Law“. - Ergebnisse - - Die Erfassung der Samenbaumparameter von B. pendula führte zu flächenspezifischen und signifikanten Unterschieden in der Dimension, Höhe und soziologischen Stellung. Für die Darstellung der Durchmesser-Höhenverteilungen erwiesen sich logarithmische und quadra-tische Funktionen gleichermaßen geeignet. Das Kronenprozent ereichte im Mittel Werte zwi-schen 37 % und 49 %. Die einzelnen Kronenparameter (Kronendurchmesser, Kronenlänge und Kronenmantelfläche) zeigten straffe lineare Zusammenhänge. Innerhalb der Kronen-strukturen (z. B. Blatt- und Zweigtrockenmasse) ließen sich zum Teil allometrische Be-ziehungen nachweisen. Im Rahmen der Vollbaumbeerntung war ein durchmesserabhängiger Fruchtbehang nachweisbar, der für den Einzelbaum eine Anzahl zwischen 2,3 und 4,2 Millionen Diasporen erreichte. - Mit den Erhebungen zur zeitlichen Ausbreitungsdynamik der Diasporen waren durch mehrjährige Untersuchungszeiträume, auch für eine Pionierbaumart wie B. pendula, stärkere Samenjahre nachzuweisen. Die räumliche Modellierung der anemochoren Diasporenaus-breitung belegte erwartungsgemäß bessere Modellanpassungen für den anisotropen (richtungsgebundenen) Modellansatz. Dennoch zeichneten sich sowohl jahres- als auch flächenspezifisch deutliche Unterschiede in der Modellgüte ab. Als maximale Diasporen-dichte pro m² wurde ein Wert von 20.700 Diasporen ermittelt. Die mittleren Ausbreitungs-distanzen (MDD - “Mean Dispersal Distances“) lagen nach Modellschätzung für die ge-samten Beprobungszeiträume und unter Berücksichtigung aller Versuchsflächen zwischen 37 m und 90 m. Die durchschnittliche Diasporenproduktion eines Einzelbaumes lag nach Anga-ben des Modells in einem Bereich von 180.000 bis 7.400.000. Die Qualitätsansprache an den Diasporen ergab einen Anteil von etwa 5 % bis 8 % äußerlich Schadhaften. Der unmittelbare Windeinfluss auf Hauptausbreitungsrichtung und -entfernung konnte ebenfalls nachgewiesen werden. - Untersuchungen zum Keimlingsstadium zeigten deutliche Abhängigkeiten zwischen den ausgewählten Bodendeckungsvarianten, der Keimlingsdichte und dem Keimlingswachstum. Sand-Birkenkeimlinge waren sowohl unter Bestandesbedingungen als auch unter den freif-lächenähnlichen Bedingungen des Mitscherlich-Gefäßversuchs auf der Variante mit Mine-ralboden besonders dicht aufgelaufen, blieben jedoch stark in ihrer weiteren Entwicklung zurück. Als besonders wüchsig erwiesen sich Keimlinge auf den Bodendeckungsvarianten mit Nadelstreuauflage und in D. flexuosa. Sand-Birkenkeimlinge der Bodendeckungsvarianten ohne Konkurrenz durch Bodenvegetation (Mb, Nd) besaßen eine längere Hauptwurzel und eine höhere Wurzelmasse (56 % - 60 % der Gesamtmasse). Die oberirdische Allokation (Blatt- und Sprossmasse) fiel hingegen für Sand-Birkenkeimlinge in den Bodendeckungs-varianten mit C. villosa und D. flexuosa höher aus. Verteilungs- und Konkurrenzerhebungen in den Gefäßversuchen erbrachten signifikante Zusammenhänge zwischen Keimlingsdichte, Standraum und Wachstum der Einzelpflanze. - Das Sämlingsstadium und die älteren Verjüngungspflanzen wiesen einen deutlichen Rückgang in der Mortalität auf. Die Erhebungen im Bestand ergaben ein unterschiedliches Durchschnittsalter für Sand-Birken auf den einzelnen Bodendeckungsvarianten (C. villosa 7,6 Jahre, D. flexuosa 6,2 Jahre und Nadelstreu 4,7 Jahre). Die wachstumsrelevanten Umweltbe-dingungen wie Strahlungsverfügbarkeit, Feuchteregime und Entfernung zum nächsten Alt-baum unterschieden sich außerdem in Abhängigkeit von den als repräsentativ eingestuften Bodendeckungsvarianten unter Bestandesbedingungen. Das bestandesbezogene Wachstum der Sand-Birken in einem Alter von 2 bis 6 Jahren ließ sich durch eine exponentielle Funktion mit hoher Anpassungsgüte (p ≤ 0,000) abbilden. Innerhalb des Mitscherlich-Gefäßversuchs haben sich ebenfalls Unterschiede in der Individuendichte, den Mortalitäts- und Wachstums-raten in Abhängigkeit von den Bodendeckungsvarianten ausgebildet. Höchste Verjüngungs-dichten wurden nach einem 2,5jährigen Entwicklungszeitraum auf der Bodendeckungs-variante Nadelstreuauflage erreicht. Die Allokationen in der Trockenmasse näherten sich hingegen in den unterschiedlichen Varianten stärker an. Ein dichteabhängiges Wachstum konnte in der letzten Aufnahme nicht mehr nachgewiesen werden. Abschließend bleibt festzuhalten, dass die ermittelten Untersuchungsergebnisse in Abhängig-keit vom jeweiligen Verjüngungsstadium die zeitliche und räumliche Präsenz, Konkurrenz- und Entwicklungsfähigkeit der Sand-Birke in Fichtenaltbeständen des Tharandter Waldes charakterisieren. Sie belegen eine kleinstandörtliche Heterogenität in den untersuchten Beständen, die sich nachhaltig auf die Etablierung der hier untersuchten Pionierbaumart auswirkt. Anhand der räumlichen Modellierung lässt sich die zu erwartende Verteilung von Diasporen und Keimlingen in Abhängigkeit von den Positionen der Samenbäume prognostizieren. Insgesamt ergibt sich aus den vorliegenden Ergebnissen ein vergleichsweise hohes Verjüngungspotenzial für B. pendula, das sich durch waldbauliche Maßnahmen effizient nutzen ließe. Ein detailliertes Wissen über die einzelnen Verjüngungsstadien bietet zudem die Möglichkeit einer gezielten waldbaulichen Steuerung der Baumart und zur Risikoabschätzung des Verjüngungserfolgs unter den gegebenen Rahmenbedingungen. Bei einer wachsenden waldbaulichen Unsicherheit im Umgang mit unterschiedlichsten Klima-prognosen, die sich in ihrer Wirkung regionalspezifisch erheblich unterscheiden können, sollte die Sand-Birke als Misch- und Vorwaldbaumart unbedingt berücksichtigt werden. Um dem viel zitierten Anspruch an die Nachhaltigkeit waldbaulichen Handelns gerecht zu werden, muss die Option zur Integration von B. pendula gewährleistet bleiben, auch für künftige Generationen und bei sich wandelnden Ansprüchen an den Wald
- Objectives - The main goal of this study was to describe comprehensively the particular stages of the regeneration cycle of Betula pendula Roth. Investigations were carried out in local stand and site conditions of a research area in South-East Germany (Tharandter Forest) are considered. In this context options for integrating Silver birch regeneration into silvicultural management concepts of old Spruce stands (Picea abies L.) with lacking vitality are pointed out. - Research area - The Tharandter Forest is located (50°00’N, 13°35’E.) in Saxony (South-East Germany) with an area of around 6.000 ha. It is dominated by Norway spruce stands, and ranges from colline to submontane altitudinal belt (350 to 420 m a.s.l.). These sites are part of the northern declivity of the Ore Mountains. Mono-layered Norway spruce stands with soils of medium trophy and well drained, but featured highly variable soil moisture levels during the growing season were selected for this study. The stand age was ≥ 80 years. Seed trees of Silver birch were mixed as single trees or small groups. - Methodical aspects - The methodical work was concentrated on relevant regeneration aspects like fructification of seed trees, seeds, seedlings, saplings and established regeneration of Silver birch. Growth parameters of seed trees and the amount of fructification were used to quantify allometric relationships. The multi-level research design was based on measurements under stand conditions, pot and laboratory experiments. Seed traps and plots (1m x 1m) were located in spruce stands with regard to different stages of Silver birch development. Therefore micro-environmental growth conditions like soil humidity and photosynthetic active radiation were measured, and plants of ground cover characterized. As examples of ground cover variants with highest presence in homogeneous spruce stands mineral soil, needle litter, Calamagrostis villosa CHAIX (GMEL.) und Deschampsia flexuosa L. (TRIN.) were chosen. Using the program WALDSTAT (NÄTHER & WÄLDER 2003) spatial distribution of dispersed seeds (diaspores) and seedlings could be modelled. Additionally pot experiments were done to compare quantitative and qualitative development of birch seedlings between stand and open site conditions. Regeneration density, number of leaves, shoot and root growth and allocations were measured as important growth parameters to evaluate single plant development under different environmental conditions. Finally, spatial distribution of seedlings in microsites and intraspecific competition were calculated by tessellation models, aggregation indices after CLARK & EVANS, Gini-coefficient and ‘constant yield law’. - Main results - - Measurements on seed trees of B. pendula indicate stand specific differences significantly in dimension, height and biosocial position of trees within the birch population (crown classes). For specific height-dbh curves logarithmic and quadratic equations were adapted. The relative crown length for seed trees was located between 37 % and 49 %. Allometric relationships between crown parameters (e.g. crown diameter, crown length and crown surface) were strongly correlated. In specific cases crown structures (e.g. dry mass of leaves and twigs) were also correlated, certainly with different grades. Direct seed counting of felled seed trees provided the relationships between dbh and number of seeds. Counted seeds for single Silver birch trees ranged between 2.300.000 - 4.200.000. - As one result of seed trapping huge varieties in seed production of Silver birch were detectable between years with different seed potential. Spatial modeling of seed dispersal supported strong influences caused by wind (direction and speed). Hence, best fitted model estimations were found for anisotropic scenarios. The maximum in seed density was recorded with 20.700 seeds per m². As data for ‘Mean Dispersal Distances’ (MDD) the program WALDSTAT calculated between 37 m and 90 m. Furthermore the amount of seeds produced by a single tree was estimated with 180.000 - 7.400.000 depending on dbh. Physical quality evaluations for seeds have shown a mean proportion of damaged and not germinable seeds between 5 % and 8 %. - Direct effects of ground cover variants have been identified for seedling density and growth. Seedling density was highest on mineral soil for both, stand conditions and pot experiment, but these birch seedlings developed slowly compared with individuals in the other ground cover variants. The best growth was realized by birch seedlings in needle litter and D. flexuosa. Regarding to root length and mass, birches in ground cover variants without grass competition (mineral soil and needle litter) have shown a significant better development of underground parts. Root dry mass of these birch seedlings reached proportions between 56 % and 60 % of whole plant dry mass. By contrast the aboveground dry mass (leaves and shoot) was higher for birches competing with grasses. Overall results of birch seedling distribution and competition were significant correlations between densities, space, and growth per single plant. - For saplings and established birch regeneration a notable decrease in mortality rates were found. According to regeneration analyses under stand conditions age distributions in Silver birch regeneration have been controlled by ground cover variants and their environment conditions. The average age of Silver birch seedlings was high in areas with C. villosa (7.6 years) and low in needle litter (4.7 years). Furthermore growth influencing environmental conditions like light, humidity, and distance of old spruce trees have shown differences between variants in ground cover. The growth of regenerated Silver birches at the age of 2 to 6 years under those stand conditions can be described by an exponential function with high degree of adaptation (p ≤ 0,000). There were also differences in sapling densities, mortality and growth rates caused by ground cover variants in the pot experiments. After 2.5 years maximum regeneration densities in pots were registered on ground covers with needle litter. Allocations in regeneration dry mass were less influenced by ground cover variants than in previous stages. Density dependent growth rates could not be proved during last measurements. Finally, the presented results provide the opportunity to characterize temporal and spatial presence of different regeneration stages of Silver birch, its potential of competition and further development in old Norway spruce stands of the Tharandter Forest. They document heterogeneous structures of micro-environmental conditions in these spruce stands, which have sustainable effects on regeneration establishment of this studied pioneer tree species. On the basis of spatial modeling it is possible to estimate spatial distribution of seeds and seedlings depending on seed tree positions. Overall the results involve a high potential of successful regeneration in Silver birch, which opens up promising vistas for silvicultural management. More detailed knowledge in particular regeneration stages induces possibilities for selective control in silviculture with Silver birch. Additionally, estimating the regeneration risks and the success under given surrounding conditions will be more precisely. Considering uncertainty in giving prognoses for climate change Silver birch should be integrated in silvicultural strategies because of its role as admixed tree species and pioneer crop combined with comparably high resilience against warming

3,4-Methylenedioxymethamphetamine (MDMA) use has increased dramatically and more intensive patterns of use such as binging have become common. This thesis pays particular attention to the translation of animal data to humans by examining low doses and binge type repeated regimen of MDMA in the rat. The functional effects especially acute and long-term effects on memory have been investigated together with the measurement of changes in 5-HT and dopamine to investigate the possible link of these neurotransmitters and the functional effects of MDMA. The acute effect of single low doses of MDMA on memory was initially examined and it was shown that MDMA (3 mg/kg) acutely disrupted novel object discrimination when given 30 min before the test. However there was no change in 5-HT and dopamine in the hippocampus, striatum and frontal cortex 150 min after MDMA administration. The combined techniques of radiotelemetry and in vivo microdialysis were used to examine effects of 'binge-type' repeated low dose MDMA administration (3 or 6 mglkg i.p. x 3 every 2 h). Locomotor activity, body temperature and 5-HT release in the hippocampus were simultaneously measured in the same animal during MDMA administration. MDMA (3 x 6 mglkg) increased locomotor activity after each injection. In addition MDMA (3 x 3 mg/kg) produced hypothermia following each injection while MDMA (3 x 6 mg/kg) changed thermoregulation as it decreased body temperature after the first injection and then increased body temperature after the second to a maximum of + 1.3 °C after the third injection. Both 'binge' doses of MDMA however increased extracellular 5-HT in the hippocampus after each injection and there was no correlation between 5-HT release in the hippocampus and changes either in locomotor activity or body temperature. The long-term effect of repeated administration of low doses of MDMA (3 or 6 mg/kg i.p. x 3 every 2 h) on memory was investigated using novel object discrimination 2 weeks after treatment. To imitate the single housing condition used in radiotelemetry experiments, rats were individually housed during drug treatment. MDMA (3 x 6 mglkg) caused impairment of novel object discrimination but there was no change in 5-HT, dopamine and their metabolites in the hippocampus, striatum and frontal cortex 2 weeks after MDMA treatment suggesting no contribution of either 5-HT or dopamine loss to the MDMA-induced memory impairment. The effects of housing conditions on MDMA-induced changes in body temperature and subsequent 5-HT neurotoxicity were determined. Group housed rats showed a similar pattern of changes in body temperature to singly housed rats measured by radiotelemetry following MDMA (3 x 6 mg/kg) suggesting no effect of the housing condition on MDMA-induced changes in body temperature. MDMA (3 x 6 mg/kg) given to group housed rats however produced loss of hippocampal 5-HT 2 weeks after treatment indicating that MDMA-induced hyperthermia is not an essential factor for MDMA-induced neurotoxicity. The influence of tyrosine on MDMA-induced 5-HT neurotoxicity was determined by depletion of brain tyrosine availability by giving a tyrosine-free amino acid mixture (1 glkg twice 1 h apart) to Dark Agouti rats before and after MDMA administration (12.5 mglkg i.p.). A small increase of tyrosine in the hippocampus and striatum occurred in rats treated with MDMA alone. Although the tyrosine-free amino acid mixture decreased tyrosine in the hippocampus and striatum by more than 50% 2 h after administration, this did not protect against MDMA-induced acute hippocampal and striatal 5-HT depletion and long-term 5-HT loss in the hippocampus indicating no effect of tyrosine on MDMA-induced 5-HT neurotoxicity. Overall the results of the present study provide extensive evidence for acute and long-term memory impairments following single and 'binge-type' repeated low dose MDMA administration and that these effects may translate effectively to human conditions. The memory impairments appeared to have no link with 5-HT and dopamine thus it is important to focus on other factors involved in the mechanism of MDMA-induced memory impairments.