Darmstadt, Techn. Univ., Diss., 2002. / Dateien im PDF-Format

L'architecture des plantes est le résultat combiné des développements des structures topologique et géométrique qui interviennent dans l'acquisition de la biomasse et sa répartition sous l'influence des processus physiologiques. Pourtant cet aspect a été longtemps négligé dans la communauté des modèles dynamiques. Récemment les modèles structures fonction se sont montrés pertinents pour prendre en compte des questions comme les interactions plantes environnement (l'interception de la lumière), les interactions entre croissance et développement (répartition de la biomasse) en se plaçant au niveau de l'organe. Cependant les couts en calcul de la simulation numérique de ces processus rendent les applications impraticables en agriculture. Cette thèse vise a combiner le modèle structure fonction Greenlab avec d'une part un modèle de culture et d'autre part un modèle forestier basés sur le peuplement afin d'y introduire le concept d'architecture des plantes. Le modèle de culture Pilote fournit des prédictions de récoltes basés sur les paramètres de l'environnement (radiation, précipitations) et l'indice foliaire et l'indice de récolte. Une étude sur Maïs conjointe entre Pilote et GreenLab a permis d'expliciter en détail les paramètres de la production. Les indices foliaires et de récolte dépendent directement des paramètres sources puits, et la variabilité individuelle entre plantes est explicitée directement par les variations des retards a la germination et celles des surfaces disponibles par plantes (compétition spatiale). Tous ces paramétrés peuvent être calibré par méthodes inverses. Ainsi la jonction des deux types de modèles est réalisée au niveau du passage de la plante au peuplement.Une autre étude conjointe a été effectuée avec le modèle forestier empirique PNN qui modélise la croissance des peuplements forestiers de Pins noirs. A partir des données statistiques classiques sur les mesures de troncs et de houppiers, combinées avec les connaissances architecturales du Pin issues d'AMAP, GreenLab peut restituer l'architecture de l'arbre et visualiser des scenarios de sylviculture incorporant des élagages. Le procédé va jusqu'à l'obtention d'images de synthèse réalistes des peuplements. En conséquence il semble efficace de coupler les modèles de cultures et les modèles forestiers qui intègrent les connaissances écophysiologiques au niveau peuplement avec les modèles structures fonctions qui intègrent ces connaissances au niveau de l'architecture de la plante. Le modèle GreenLab par ses affinités avec ces deux types de modèles et ses performances en calcul, permet d'apporter un complément d'information essentiel sur la description du fonctionnement d'un peuplement tant du point de vue développement, que du point de vue des relations sources puits dans la plante. Enfin le modèle couplé a une plateforme comme Xplo (AMAP) permet en plus une simulation réaliste 3D du peuplement végétal aux divers stades de la croissance. / Plant architecture implies the development of both topological and geometrical structure over time, which determines resource acquisition, in the meantime interacts with physiological processes. However it has long been overlooked in traditional community dynamics models. Based on plant architecture, functional-structural plant models (FSPM) have showed their particular capability in addressing questions like interactions between plant and environment (e.g. light interception), between structure development and growth (e.g. carbon allocation), as they take into account morphogenesis with organ-level explicit descriptions. Anyway, high demand of time and memory for simulation and inverse calculation prevents FSPM from further agricultural or sylvicultural practice. This thesis attempts the combination of a mathematic FSPM GreenLab and a crop model or an empirical forest model (EFM) to introduce individual-based architectural support for community growth study. In the case of maize, disagreement from stand level (by crop model PILOTE) and individual level (by GreenLab) growth simulations implies different emergence time of individuals, which is used to quantify the distribution. By supposing that theoretical projective area (Sp) is determined by the growth situation and the final size of individual architecture, the variance of Sp is reversely computed with the variance of organ compartment measurements to characterize individual variability. In the case of Black pine, architecture dynamics built in GreenLab according to Rauh's model (architecture model for pine tree) are adapted to the simulation of an EFM PNN. As a consequence, thinning scenarios are well incorporated in the final stand visualization. From these preliminary applications, following conclusions can be drawn: (i) FSPM is able to provide individual performances (i.e. organ development and expansion) inside an area of crop field for crop models. (ii) The crop model may regulate the combined form of individuals from integral level. Both aspects are significant to deepen understanding of stand growth. (iii) Architecture conceptions integrated in FSPM may be adapted to EFM simulations for a data-driven visualization. (iv) EFM can guarantee ecological/sylvicultural function for 3D stand visualization. To take into consideration biomass processes, additional observations are needed. As models are independent in combinations, the same methods can be extended to linkage with other stand models.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23070号 / 医博第4697号 / 新制||医||1049(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 花川 隆, 教授 溝脇 尚志, 教授 高橋 淳 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Hintergrund: Bei erwachsenen Patient*innen mit Erkrankungen aus dem Schizophrenie-Spektrum konnte im transkraniellen Ultraschall im Vergleich zu gesunden Proband*innen eine signifikant erhöhte Echogenität der Substantia Nigra (SN) nachgewiesen werden. Zudem bestand ein Zusammenhang zwischen der SN-Fläche und stärker ausgeprägten extrapyramidalmotorischen Bewegungsstörungen unter Antipsychotikatherapie. In der vorliegenden Arbeit wurde überprüft, inwiefern die Echogenität der SN auch bei Jugendlichen und jungen Erwachsenen als Biomarker für Erkrankungen aus dem psychotischen Formenkreis und als Korrelat psychopharmakologischer Nebenwirkungen herangezogen werden kann. Des Weiteren wurde der Einfluss von Alter, Krankheitsdauer sowie Antipsychotika-Lebenszeitdosis auf die SN-Echogenität untersucht sowie Zusammenhänge mit peripheren Eisenparametern. Methoden: Hierfür wurden insgesamt 16 stationär behandelte Patient*innen zwischen 14 – 22 Jahren mit Erkrankungen aus dem schizophrenen Formenkreis sowie nach Alter und Geschlecht gematchte gesunde Kontrollen mittels TCS untersucht. Aus peripher entnommenem Blut wurden Parameter des Eisenhaushalts bestimmt. Ergebnisse: Es konnten entgegen der Hypothese keine signifikanten Unterschiede in Bezug auf die Echogenität der SN im Vergleich zur gesunden Kontrollgruppe festgestellt werden. Bezüglich der Schwere der beobachteten EPMS ergab sich entgegen der Hypothese und im Kontrast zu Befunden bei Erwachsenen kein Zusammenhang mit der SN-Echogenität. Das Alter der Proband*innen, die Krankheitsdauer sowie die Dosis der eingenommenen Antipsychotika zeigten keine Zusammenhänge mit der SN-Echogenität. Interessanterweise zeigte sich eine signifikant negative Korrelation zwischen der echogenen Fläche der SN und Eisen sowie Transferrin. Schlussfolgerung: Im Jugend- und jungen Erwachsenenalter eignet sich die SN-Echogenität vermutlich nicht als Biomarker für Erkrankungen aus dem Schizophrenie-Spektrum oder für die Prädiktion von Nebenwirkungen antipsychotischer Medikation. Möglicherweise manifestiert sich eine erhöhte Echogenität der SN, welche als Zeichen für eine Schädigung der dopaminergen Neurone gesehen wird, bei schizophrenen Psychosen erst im Verlauf der Krankheit. Da wir die Studienteilnehmer*innen nur zu einem einzigen Zeitpunkt im Laufe ihrer Krankheitsgeschichte untersuchten, kann keine Aussage über den weiteren Verlauf der SN-Echogenität getroffen werden. Hierfür wären longitudinale Untersuchungen zielführend, da nur so mögliche entwicklungsbedingte Veränderungen festgestellt werden können. / Background: Adult patients with schizophrenic spectrum disorders showed a significantly larger mean echogenic area of the subtantia nigra (SN) in transcranial sonography compared to healthy controls. Also, patients showing larger echogenic SN developed more severe neuroleptic-induced extrapyramidal side-effects. In this study, we examined if SN echogenicity can function as a biomarker for schizophrenic spectrum disorders and as a predictor of neuroleptic-induced extrapyramidal side-effects in adolescents and young adults. Furthermore, we investigated the correlation of age, disease duration, lifetime neuroleptic dose and iron parameters with SN echogenicity. Methods: 16 hospitalized patients who had been diagnosed with schizophrenic spectrum disorders and 16 healthy controls between the ages of 14 – 22 years were examined via transcranial sonography. We also assessed the concentration of iron parameters in peripheral blood samples. Results: In contradiction to our hypothesis, no significant differences regarding SN echogenicity could be found when comparing the two groups. There also was no correlation of severity of extrapyramidal side-effects, age, disease duration or lifetime neuroleptic dose with echogenicity of the SN. Interestingly, we found a significant negative correlation of SN echogenicity with serum iron as well as serum transferrin levels. Conclusion: SN echogenicity apparently cannot be used as a biomarker for schizophrenic spectrum disorders or a predictor of neuroleptic-induced extrapyramidal side-effects in adolescents and young adults. Increased SN echogenicity, which is assumed to be an indicator of nigrostriatal injury, presumably evolves much later in the course of schizophrenic disorders. As our probands underwent examination only once in the course of their disease, we cannot draw conclusions regarding the development of SN echogenicity. Longitudinal studies are needed to shed more light on possible developmental changes in this regard.

Melatonin has a neuroprotective function, which is mediated via its G-protein-coupled MT1 and MT2 receptors. When activated, various downstream pathways are triggered promoting cell protection and survival. By utilizing this function of melatonin, studies have shown positive effects in animal models of neurodegenerative disorders such as Parkinson’s disease (PD). In our previous studies, a physiological dose of melatonin was shown to have neuroprotective effects in the nigrostriatal pathway, as indicated by preservation of tyrosine hydroxylase (TH) immunoreactivity in a 6-hydroxydopamine (6-OHDA) model of PD. We also have reported that transplantation of MT1 receptor-expressing mouse neural stem cells (C17.2) along with melatonin treatment, preserved TH immunoreactivity in a similar PD model. Moreover, others have reported an increase in striatal melatonin levels in 6-OHDA-induced hemiparkinsonian rats. Based on these implications of a close relationship between the dopaminergic and melatonergic systems, we hypothesize that degeneration of dopaminergic neurons induced by 6-OHDA will affect the melatonergic system in the nigrostriatal pathway. In this study, 6-hydroxydopamine was unilaterally injected in the rat striatum or medial forebrain bundle. An apomorphine rotation test showed significant increases in net contralateral rotations (p<0.01) in lesioned animals as compared to sham. Also, a loss of TH immunoreactivity in the striatum and substantia nigra was seen in striatum lesioned groups, confirming lesion-induced degeneration of dopaminergic neurons in the nigrostriatal pathway. There were no significant differences in MT1 receptor protein expression in the striatum and substantia nigra, between all intrastriatal lesioned groups and the sham group. However, 6-OHDA lesions in the medial forebrain bundle caused a significant increase in MT1 receptor mRNA expression on the lesioned side (right) of the ventral midbrain as compared with the contralateral side. These results suggest that MT1 receptors are upregulated in the ventral midbrain following lesion-induced dopaminergic neurodegeneration, and may be involved in an endogenous neuroprotective mechanism. / Thesis / Master of Science (MSc)

No / Nursing has reciprocal benefits for both mother and infant, helping to promote maternal behavior and bonding. To test the "rewarding" nature of nursing, functional magnetic resonance imaging was used to map brain activity in lactating dams exposed to their suckling pups versus cocaine. Suckling stimulation in lactating dams and cocaine exposure in virgin females activated the dopamine reward system. In contrast, lactating dams exposed to cocaine instead of pups showed a suppression of brain activity in the reward system. These data support the notion that pup stimulation is more reinforcing than cocaine, underscoring the importance of pup seeking over other rewarding stimuli during lactation

No description available.

Over 15 million contact sports players and military veterans are at risk for the development of chronic traumatic encephalopathy (CTE), a neurodegenerative disease associated with exposure to repetitive head impacts (RHI) that sometimes presents with parkinsonian motor symptoms, although very little is understood about how these individuals develop parkinsonism. CTE is characterized by accumulation of hyperphosphorylated tau protein (p-tau), and diagnosis requires the presence of neuronal tau in the form of neurofibrillary tangles at the depth of cortical sulci. We performed quantitative immunoassays for markers of neurovascular inflammation within the postmortem dorsolateral frontal cortex of participants with and without a history of RHI and CTE (n = 156), and tested for associations with RHI, microgliosis, and tau pathology measures. Levels of vascular injury-associated markers were increased in CTE compared to RHI-exposed and -naïve controls. Markers increased with RHI exposure duration and were associated with increased microglial density and tau pathology. Histologically, there was significantly increased ICAM1 staining of the microvasculature, extracellular space, and astrocytes at the sulcal depths in high stage CTE compared to both low stage CTE and controls. Multifocal perivascular immunoreactivity for serum albumin was present in all RHI-exposed individuals. These findings demonstrate that vascular injury markers are associated with RHI exposure, duration, and microgliosis, are elevated in CTE, and increase with disease severity. We next performed a cross-sectional analysis of all brain donors with CTE and without comorbid neurodegenerative disease (n=495) in the UNITE Brain Bank. Participants with parkinsonism (CTE-p, n=119) had a higher mean age at death (71.5 years (y)) than participants without parkinsonism (CTE-np, n=362, 54.1 y) and exhibited a higher rate of dementia than CTE-np participants. CTE-p participants had a more severe CTE stage and nigral pathology (NFTs, neuronal loss, and more frequent Lewy bodies), though the majority of cases were negative for nigral Lewy bodies. In American football players, simultaneous regression analysis demonstrated that nigral NFTs and neuronal loss mediate a connection between years of play and parkinsonism in CTE. In this cross-sectional study of contact sports athletes with CTE, years of contact sports participation was associated with SN proteinopathy and neuronal loss, and these pathologies were associated with parkinsonism. Finally, in a postmortem cohort (n=392) of brain donors with CTE without comorbid neurodegenerative disease, we used linear regression modelling to analyze the associations between isodendritic core nuclei pathology (semiquantitative neurofibrillary tangles (NFTs), neurites, and neuronal loss scores) and CTE disease severity, RHI exposure duration (years of contact sport play), and informant-reported cognitive and daily function as assessed by the Cognitive Difficulties Scale (CDS) and Functional Activities Questionnaire (FAQ), respectively. Overall, isodendritic core (IC) NFT scores increase with disease stage, Initially in the locus coeruleus and finally in the median raphe nuclei. Neuronal loss occurred at later disease stages than NFT accumulation. RHI exposure was associated with p-tau pathology for all IC regions. NFTs and neuronal loss in the substantial nigra were associated with increased CDS scores (i.e., worse cognitive function), and neuronal loss in the substantia nigra and locus coeruleus were associated with increased FAQ scores (i.e., worse daily function). We are able to show CTE is similar in distribution of p-tau pathology to progressive supranuclear palsy (PSP), a disease that is thought to primarily affect subcortical regions, especially by end stage disease. These results demonstrate the vulnerability of the isodendritic core nuclei to p-tau pathology and neuronal loss in CTE, and suggest that their involvement contributes to cognitive and functional symptoms during life. This work highlights the possible linkage between neuroinflammation leading to nigral p-tau accumulation and neuron loss which likely underlies the development and progression of parkinsonian motor symptoms in CTE.

The goal of this research was to determine the interactions between forage and tree components of a silvopasture system. Two studies were performed on adjacent sites established in 1995 at Virginia Tech's Kentland Research Farm. The objectives of the studies were to: 1. Determine the influence of honey locust and black walnut silvopastures on indicators of soil quality when compared to open pasture. 2. Determine if silvopasture systems changed forage mass production and soil water compared to open pastures. The study on soil quality indicators was performed in a previously grazed silvopasture. Samples were collected from the upper 15 cm of soil at three distances from the tree rows. Total N (p= 0.0219), total C (p= 0.0216), extractable P (p= 0.063), extractable K (p= 0.0347) and microbial organic C (p= 0.0255) were greater in honey locust silvopastures. The highest concentration of soil nutrients and best soil physical and chemical properties were observed 1.5 m from the tree stem. Forage growth and soil water were measured in silvopastures in 2006 and 2007. In 2006 there was higher forage growth in the black walnut and honey locust than beneath 70% shade cloth. In 2007, with a 50% shade cloth, forage growth was similar in all treatments. Initial soil water content was highest under shade cloth in 2006. In 2007 the rate of soil drying was lowest beneath the shade cloth. The presence of trees did not negatively effect forage growth and silvopasture systems improved the soil quality indicators compared to open pasture. / Master of Science

Dominance rank often determines the share of reproduction an individual male can secure in group-living animals (i.e. dominance rank-based reproductive skew). However, our knowledge of the interplay between individual and social factors in determining rank trajectories of males is still limited. The overall aim of this thesis was therefore to investigate mechanisms that underlie individual dominance rank trajectories in male crested macaques (Macaca nigra) and to highlight potential individual and social determinants of how males can achieve and maintain the highest rank possible. Data for this thesis were collected on 37 males during a field study on a natural population of crested macaques living in the Tangkoko-Batuangus Nature Reserve in Indonesia. In study 1, I validate Elo-rating as a particularly well suited method to quantify dominance hierarchies in animal species with dynamic dominance relationships. In studies 2 and 3, I suggest a personality structure for crested macaque males consisting of five distinct factors and further demonstrate that two personality factors determine whether males will rise or fall in rank. Finally, in study 4, I present results on how males utilize coalitions to increase their future rank. Together, these results shed light on how individual attributes and social environment both can impact male careers. Ultimately, in order to understand what determines rank-based reproductive skew, we need to consider the complexity and likely diversity of the mechanisms underlying rank trajectories of individual males which are likely to differ across different species.