Neste estudo, foi determinado o dano celular em linfócitos periféricos após exposição ao 153Sm-EDTMP (Samário-153 etilenodiaminotetrametilenofosfonato) por meio da técnica de análise de micronúcleos e coloração diferencial. O 153Sm-EDTMP é um radiofármaco utilizado para alívio da dor em pacientes com metástase óssea. A análise da freqüência de micronúcleos em amostras sangüíneas de pacientes obtidas uma hora após a administração endovenosa do radiofármaco (41 MBq/kg) mostrou que não houve diferença estatística em relação aos valores basais em células binucleadas. Porém, a análise da distribuição do dano em células mononucleadas mostrou que os pacientes sem tratamento radioterápico prévio apresentaram um aumento significativo na freqüência de células com um micronúcleo e aqueles com tratamento radioterápico prévio, nas células com dois ou mais micronúcleos. Os experimentos in vitro realizados com exposição de sangue total a três concentrações radioativas de 153Sm-EDTMP (0,370; 0,555 e 1,110 MBq/mL) por uma hora mostraram um aumento na freqüência de micronúcleos e de células necróticas e apoptóticas com o aumento da dose de radiação. Foram construídas curvas dose-resposta para os indivíduos sadios e para os pacientes com metástases óssea sem prévio tratamento radioterápico. A comparação das curvas mostrou que os pacientes apresentaram uma radiossensibilidade mais alta que os indivíduos sadios tanto quanto a porcentagem de células com micronúcleos como de células mortas (necróticas e apoptóticas). / In this study the cellular damage in peripheral lymphocytes after exposure to 153Sm-EDTMP (Samarium-153 ethylenediaminetetrametylenephosphonate) was determined using the technique of micronuclei analysis and differential coloration. 153Sm- EDTMP is a radiopharmaceutical used for pain relief in patients with bone metastases. The analysis of the frequency of micronuclei in patient blood samples obtained one hour after endovenous administration of radiopharmaceutical (41 MBq/kg) showed no statistical difference in relation to basal values in binucleated cells. However the analysis of damage distribution in mononucleated cells, showed that the patients without previous radiotherapic treatment presented a significant increase in the frequency of cells with one micronucleus and in those who had taken previous radiotherapic treatment, in cells with two or more micronuclei. The in vitro experiments conducted with the exposition of total blood to three radiation concentrations of 153Sm-EDTMP (0.370, 0.555 and 1.110 MBq/mL) during one hour showed an increase in the frequency of micronuclei and necrotic and apoptotic cells with increasing radiation dose. Dose-response curves for healthy donors and patients with bone metastasis without previous radiotherapic treatment were constructed. The comparison of the curves showed that patients presented higher radiosensitivity, either micronuclei or dead cell (necrotic or apoptotic) percentages, than healthy donors.

Ce manuscrit de thèse présente l’étude des processus d’émission de deux types de noyaux actifs de galaxie détectés aux rayons gamma : des blazars vues au TeV et des Narrow Line Seyfert 1s (NLS1s) détectés au GeV. La distribution spectrale d’énergie des blazars peut être décrite en général par des modèles 'one-zone synchrotron self-Compton'. Ce modèle a été appliqué au blazar 1ES2322-409 qui fut premièrement détecté au TeV par l’expérience HESS. Des composantes externes comme le tore, le disque d’accrétion, la couronne X ou la 'Broad Line Region' sont nécessaires pour expliquer la radiation observée dans des NLS1 qui émettent des rayons gamma. Un modèle numérique qui considère ces champs des photons externes a été développé. Ce modèle explique l’émission observée et la transition entre des états bas et des états d’émission augmentée pour trois NLS1s vues au régime gamma : 1H0323+342, B20954+25A et PMN J0948+0022. / This thesis manuscript presents the study of the emission processes of two types of gamma-emitting active galactic nuclei: TeV-detected blazars and GeV-detected Narrow Line Seyfert 1s (NLS1s).The Spectral Energy Distribution (SED) of TeV blazars can in general be well described by simple one-zone synchrotron self-Compton models. Such model has been applied to the blazar 1ES2322-409 that was first detected at TeV by the HESS collaboration.Additional external photon fields such as the obscuring torus, the accretion disc, the X-ray corona or the broad line region are necessary to describe the observed radiation and broad-band SED of gamma-emitting NLS1s. A numerical model that takes into account emission from these external fields has been developed. The model explains the observed emission and the transition from quiescent to gamma-ray flaring states of three gamma-emitting NLS1s: 1H0323+342, B20954+25A and PMN J0948+0022.

Ce travail de thèse s'inscrit dans le cadre du développement de la méthode de mélange de configurations multiparticules-multitrous visant à décrire les propriétés de structure des noyaux atomiques. Basée sur un double principe variationnel, cette approche permet de déterminer simultanément les coefficients d'expansion de la fonction d'onde et les orbitales individuelles.Dans ce manuscrit, le formalisme complet méthode de mélange de configurations multiparticules-multitrous auto-cohérente est pour la première fois appliqué à la description de quelques noyaux des couches p et sd, avec l'interaction de Gogny D1S.Un première étude du 12C est effectuée afin de tester et comparer le double processus de convergence lorsque différents types de critères sont appliqués pour sélectionner les configurations à N-corps inclues dans la fonction d'onde du noyau. Une analyse détaillée de l'effet induit par l'optimisation des orbitales est conduite. En particulier, son impact sur la densité à un corps et sur la fragmentation de la fonction d'onde de l'état fondamental, est analysé.Une étude systématique de noyaux de la couche sd est ensuite conduite. Une analyse précise du contenu en corrélation de l'état fondamental est effectuée, et quelques quantités observables telles que les énergies de liaison et de séparation, ainsi que les rayons de charge, sont calculées et comparées à l'expérience. Les résultats obtenus sont satisfaisants. La spectroscopie de basse énergie est ensuite étudiée. Les énergies d'excitation théoriques sont en très bon accord avec les données expérimentales, et les caractéristiques dipolaires magnétiques sont également satisfaisantes. Les propriétés quadripolaires électriques, et en particulier les probabilités de transition B(E2), sont par contre largement sous-estimée par rapport aux valeurs expérimentales, et révèle un manque important de collectivité dans la fonction d'onde, dû à l'espace de valence restreint considéré. Si la renormalisation des orbitales induit une importante fragmentation de la fonction d'onde de l'état fondamental, seul un effet très faible est obtenu sur les probabilités de transition B(E2). Une tentative d'explication est donnée.Enfin, les informations de structure fournies par la méthode de mélange de configurations multiparticules-multitrous sont utilisées comme ingrédient de base pour des calculs de réactions telles que la diffusion inélastique de protons et d'électrons sur noyaux de la couche sd. Si les résultats révèlent aussi un manque de collectivité, les tendances expérimentales sont bien reproduites et sont améliorées par l'optimisation des orbitales. / This thesis project takes part in the development of the multiparticle-multihole configuration mixing method aiming to describe the structure of atomic nuclei. Based on a double variational principle, this approach allows to determine the expansion coefficients of the wave function and the single-particle states at the same time. In this work we apply for the first time the fully self-consistent formalism of the mp-mh method to the description of a few p- and sd-shell nuclei, using the D1S Gogny interaction.A first study of the 12C nucleus is performed in order to test the doubly iterative convergence procedure when different types of truncation criteria are applied to select the many-body configurations included in the wave-function. A detailed analysis of the effect caused by the orbital optimization is conducted. In particular, its impact on the one-body density and on the fragmentation of the ground state wave function is analyzed.A systematic study of sd-shell nuclei is then performed. A careful analysis of the correlation content of the ground state is first conducted and observables quantities such as binding and separation energies, as well as charge radii are calculated and compared to experimental data. Satisfactory results are found. Spectroscopic properties are also studied. Excitation energies of low-lying states are found in very good agreement with experiment, and the study of magnetic dipole features are also satisfactory. Calculation of electric quadrupole properties, and in particular transition probabilities B(E2), however reveal a clear lack of collectivity of the wave function, due to the reduced valence space used to select the many-body configurations. Although the renormalization of orbitals leads to an important fragmentation of the ground state wave function, only little effect is observed on B(E2) probabilities. A tentative explanation is given.Finally, the structure description of nuclei provided by the multiparticle-multihole configuration mixing method is utilized to study reaction mechanisms such as electron and proton inelastic scattering on sd-shell nuclei. Although the results also suffer from the lack of collectivity, the experimental trends are well reproduced and improved by the orbital optimization.

<p>Познавање параметара нуклеарне структуре, попут шеме нивоа, функциjе густине стања и функциjе jачине прелаза су неопходне за разумевање<br />нуклеарних особина атомског jезгра. Ове величине су директно повезане са ефикасним пресеком, коjи jе битна физичка величина у нуклеарноj физици, као и теориjски са моделима jезгра. Прикупљање тачних и прецизних података о овим физичким величинама jе jедан од наjважниjих задатака у&nbsp; нискоенергетскоj нуклеарноj физици.У овом раду за одређивање ових величина коришћен jе метод двоструких гама каскада коjи се заснива на&nbsp; коинциденционоj детекциjи гама кваната коjи настаjу након захвата термалних неутрона на jезгрима мете. Циљ експеримента jе детекциjа два узастопна гама кванта коjи се емитуjу када се jезг-ро након захвата неутрона деексцитуjе са енергиjе захвата на основно или неко од нископобуђених стања.Jезгра коjа су испитивана у овом раду су⁹⁴Nb и⁵⁶Mn, а експерименти су извршени на BRR истра-живачком реактору у Будимпешти и FRM II истраживачком реактору на Техничком универзитету у Минхену, у Хаjнц Меjер-Лаjбниц центру, тим редом. Прикупљени експериментални подаци су анализирани и добиjене су информациjе о шеми нивоа и емитованих гама кваната приликом чега jе пронађен велики броj нових гама прелаза унутар ових jезгара (210 за ⁹⁴Nb, 50 за⁵⁶ Mn) , као и нових енергетских нивоа у овим jезгрима (29 за ⁹⁴ Nb, 24 за<br />⁵⁶ Mn). За детектоване каскаде израчунати су и интензитети. Након одређивања интензитета кас-када, за одређивање функциjе густине нивоа и jа-чине прелаза за<br />⁹⁴ Nb и ⁵⁶ Mn коришћен jе практични модел за гама распад неутронских резонанци, развиjен на Обjедињеном институту за нуклеарна истраживања у Дубни, Руска федерациjа. Такође, у овом раду jе одрађена и систематизациjа података за 43 jезгра коjа су раниjе испитивана овом методом и представљени су закључци добиjени овом систематизациjом.</p> / <p>Poznavanje parametara nuklearne strukture, poput šeme nivoa, funkcije gustine stanja i funkcije jačine prelaza su neophodne za razumevanje<br />nuklearnih osobina atomskog jezgra. Ove veličine su direktno povezane sa efikasnim presekom, koji je bitna fizička veličina u nuklearnoj fizici, kao i teorijski sa modelima jezgra. Prikupljanje tačnih i preciznih podataka o ovim fizičkim veličinama je jedan od najvažnijih zadataka u&nbsp; niskoenergetskoj nuklearnoj fizici.U ovom radu za određivanje ovih veličina korišćen je metod dvostrukih gama kaskada koji se zasniva na&nbsp; koincidencionoj detekciji gama kvanata koji nastaju nakon zahvata termalnih neutrona na jezgrima mete. Cilj eksperimenta je detekcija dva uzastopna gama kvanta koji se emituju kada se jezg-ro nakon zahvata neutrona deekscituje sa energije zahvata na osnovno ili neko od niskopobuđenih stanja.Jezgra koja su ispitivana u ovom radu su⁹⁴Nb i⁵⁶Mn, a eksperimenti su izvršeni na BRR istra-živačkom reaktoru u Budimpešti i FRM II istraživačkom reaktoru na Tehničkom univerzitetu u Minhenu, u Hajnc Mejer-Lajbnic centru, tim redom. Prikupljeni eksperimentalni podaci su analizirani i dobijene su informacije o šemi nivoa i emitovanih gama kvanata prilikom čega je pronađen veliki broj novih gama prelaza unutar ovih jezgara (210 za ⁹⁴Nb, 50 za⁵⁶ Mn) , kao i novih energetskih nivoa u ovim jezgrima (29 za ⁹⁴ Nb, 24 za<br />⁵⁶ Mn). Za detektovane kaskade izračunati su i intenziteti. Nakon određivanja intenziteta kas-kada, za određivanje funkcije gustine nivoa i ja-čine prelaza za<br />⁹⁴ Nb i ⁵⁶ Mn korišćen je praktični model za gama raspad neutronskih rezonanci, razvijen na Objedinjenom institutu za nuklearna istraživanja u Dubni, Ruska federacija. Takođe, u ovom radu je odrađena i sistematizacija podataka za 43 jezgra koja su ranije ispitivana ovom metodom i predstavljeni su zaključci dobijeni ovom sistematizacijom.</p> / <p>Knowledge of nuclear parameters, such as level scheme, level density function and radiative strength function is important in order to understand nuclear properties. These parameters are directly related to the value of the cross section, an important quantity in nuclear physics, and also, theoretically to nuclear models. Acquisition of precise and high quality data on these parameters is one of the most important<br />tasks in low-energy nuclear physics. To determine these parameters, in this thesis the method of the two step gamma cascade was used. This method is based on coincidence detection of gamma rays that are emitted after thermal neutron capture&nbsp; on the nucleus. The goal of the experiment is to record two consecutive gamma rays &nbsp; that are emitted as nucleus decays from the capture energy to the ground state<br />or some of the low-excited states.In this work, 94 Nb and 56 Mn nuclei were investigated and the experiments were carried out at the BRR research reactor at the&nbsp; PGAA facility of the Centre for Energy Research (MTA EK), Budapest, Hungary and FRM II research reactor at the Technische Universit&uml;at M&uml;unchen, Heinz Maier- Leibnitz&nbsp; Zentrum (MLZ), Garching, Germany, respectively. Collected data were analyzed and information about level scheme and emitted gamma rays were obtained. The analysis showed that a large number of new gamma transitions, as well as new energy levels (29 for 94 Nb, 24 for 56 Mn) was detected for these nuclei (210 for 94 Nb, 50 for 56 Mn). The intensities were also calculated for all recorded cascades. After calculating the intensities of cascades, to determine the level density function and radiative strength function the practical model of neutron resonances gamma decay developed at JINR, Dubna, Russia, was used. Also, in this thesis, the systematization of results obtained for 43 nuclei previously measured by this method,&nbsp; are presented.</p>

Giacconi et al. (1962) discovered a diffuse cosmic X-ray background with rocket experiments when they searched for lunar X-ray emission. Later satellite missions found a spectral peak in the cosmic X-ray background at ~30 keV. Imaging X-ray satellites such as ROSAT (1990-1999) were able to resolve up to 80% of the background below 2 keV into single point sources, mainly active galaxies. The cosmic X-ray background is the integration of all accreting super-massive (several million solar masses) black holes in the centre of active galaxies over cosmic time. Synthesis models need further populations of X-ray absorbed active galaxy nuclei (AGN) in order to explain the cosmic X-ray background peak at ~30 keV. Current X-ray missions such as XMM-Newton and Chandra offer the possibility of studying these additional populations. This Ph.D. thesis studies the populations that dominate the X-ray sky. For this purpose the 120 ksec XMM-Newton Marano field survey, named for an earlier optical quasar survey in the southern hemisphere, is analysed. Based on the optical follow-up observations the X-ray sources are spectroscopically classified. Optical and X-ray properties of the different X-ray source populations are studied and differences are derived. The amount of absorption in the X-ray spectra of type II AGN, which are considered as a main contributor to the X-ray background at ~30 keV, is determined. In order to extend the sample size of the rare type II AGN, this study also includes objects from another survey, the XMM-Newton Serendipitous Medium Sample. In addition, the dependence of the absorption in type II AGN with redshift and X-ray luminosity is analysed. We detected 328 X-ray sources in the Marano field. 140 sources were spectroscopically classified. We found 89 type I AGN, 36 type II AGN, 6 galaxies, and 9 stars. AGN, galaxies, and stars are clearly distinguishable by their optical and X-ray properties. Type I and II AGN do not separate clearly. They have a significant overlap in all studied properties. In a few cases the X-ray properties are in contradiction to the observed optical properties for type I and type II AGN. For example we find type II AGN that show evidence for optical absorption but are not absorbed in X-rays. Based on the additional use of near infra-red imaging (K-band), we were able to identify several of the rare type II AGN. The X-ray spectra of type II AGN from the XMM-Newton Marano field survey and the XMM-Newton Serendipitous Medium Sample were analysed. Since most of the sources have only ~40 X-ray counts in the XMM-Newton PN-detector, I carefully studied the fit results of simulated X-ray spectra as a function of fit statistic and binning method. The objects revealed only moderate absorption. In particular, I do not find any Compton-thick sources (absorbed by column densities of NH > 1.5 x 10^24 cm^−2). This gives evidence that type II AGN are not the main contributor of the X-ray background around 30 keV. Although bias effects may occur, type II AGN show no noticeable trend of the amount of absorption with redshift or X-ray luminosity. / Giacconi et al. (1962) entdeckten mit Hilfe von Raketenexperimenten auf der Suche nach Röntgenstrahlung vom Mond eine scheinbar diffuse extragalaktische Röntgenhintergrundstrahlung. Spätere Satellitenmissionen detektierten ein Maximum dieser Strahlung bei ~30 keV. Abbildenden Röntgensatelliten wie ROSAT (1990-1999) gelang es, bis zu 80% des diffusen Hintergrundes unter 2 keV in einzelne Punktquellen aufzulösen, von denen die überwiegende Mehrheit aktive Galaxienkerne waren. Der Röntgenhintergrund ist somit wahrscheinlich als die Emission der Gesamtheit aller akkretierenden superschweren (mehrere Millionen Sonnenmassen) schwarzen Löcher in den Zentren von Galaxien in der kosmischen Geschichte zu verstehen. Zur Erklärung des Maximums der spektralen Energieverteilung der Röntgenhintergrundstrahlung bei ~30 keV benötigen theoretische Modelle jedoch zusätzliche Populationen von röntgenabsorbierenden aktiven Galaxienkernen (AGN). Derzeitige Röntgenmissionen wie XMM-Newton und Chandra ermöglichen die Untersuchung dieser Quellklassen. Die vorliegende Arbeit untersucht die Quellpopulationen, die den Röntgenhimmel dominieren. Dazu wird die 120 ksec XMM-Newton Beobachtung im Marano Feld, Ziel einer früheren optischen AGN-Durchmusterung am Südhimmel, ausgewertet. Die optischen und Röntgeneigenschaften der unterschiedlichen Quellpopulationen werden untersucht und Unterschiede erarbeitet. Für die röntgenabsorbierende Objektklasse der Typ II AGN, die man als möglichen Erzeuger der Röntgenstrahlung um 30 keV betrachtet, wird aus den Röntgenspektren das Ausmaß der Absorption ermittelt. Um die Anzahl dieser selten gefundenen Objekte zu erhöhen, werden in dieser Arbeit zusätzliche Objekte aus der Röntgendurchmusterung des “XMM-Newton Serendipitous Medium Sample” einbezogen. Die Abhängigkeit der Absorption von der Rotverschiebung und der Röntgenleuchtkraft wird untersucht. Von 328 Röntgenquellen im Marano Feld konnten 140 spektroskopisch klassifiziert werden. Es wurden 89 Typ I AGN, 36 Typ II AGN, 6 Galaxien und 9 Sterne gefunden. Nur basierend auf den optischen und Röntgeneigenschaften können AGN, Galaxien und Sterne unterschieden werden. Typ I und II AGN lassen sich nicht klar trennen und zeigen große Gemeinsamkeiten in den untersuchten Eigenschaften. Mit Hilfe von zusätzlichen Aufnahmen im nahen Infraroten (K-Band) konnten erfolgreich mehrere seltene Typ II AGN identifiziert werden. Die Röntgenspektren von Typ II AGN aus dem XMM-Newton Marano Feld und dem “XMM-Newton Serendipitous Medium Sample” wurden ausgewertet. Die Objekte weisen nur eine mäßige Absorption auf und scheinen somit nicht einen Hauptbestandteil des Röntgenstrahlungshintergrundes um 30 keV zu erzeugen. Obwohl Selektionseffekte nicht vollständig verstanden sind, zeigen Typ II AGN keine erkennbare Abhängigkeit der Absorption von der Rotverschiebung oder der Röntgenleuchtkraft.

This dissertation attempts to extend the classes of halogen-containing systems which may be studied using solid-state nuclear magnetic resonance (SSNMR). As line shape broadening due to the quadrupolar interaction (QI) scales inversely with the applied field, high-field magnet technology is indispensable for this research. Combining advanced radiofrequency pulse sequences with high-field wideline data acquisition allowed for the collection of very broad SSNMR signals of all quadrupolar halogen nuclei (i.e., 35/37Cl, 79/81Br and 127I) within a reasonable amount of experimental time. The initial systems for study were of the MX2 variety (M = Mg, Ca, Sr, Ba; X = Cl, Br, I). In total, 9 anhydrous compounds were tested. The effects of hydrate formation were tested on 7 additional compounds. Systematic trends in the observed δiso values (and to a lesser extent, Ω and CQ) were found to be diagnostic of the extent of hydration in these materials. Resolving power was successfully tested using SrBr2, which possesses 4 magnetically unique sites. The composition of CaBr2•xH2O was convincingly determined using SSNMR data and the hydration trends noted above. The sensitivity of the QI to the local bonding environment (e.g., bond distance changes of less than 0.05 Å) was used to refine (when coupled with gauge-including projector augmented-wave density functional theory (GIPAW DFT) quantum chemical computations) the structure of MgBr2, and was used to correct prior NMR data for CaCl2 (earlier accounts had been performed upon a CaCl2 hydrate). During NMR data analysis of certain iodine-containing materials, it was found that standard fitting software (which uses perturbation theory) could not reproduce the observations. Proper analysis required the use of exact simulation software and allowed for the observation of high-order quadrupole-induced effects (HOQIE). This motivated further studies using rhenium-185/187 nuclei, where it was expected that HOQIE would be more dramatic. The observed rhenium SSNMR spectra possessed additional fine structure that had never been observed before experimentally, nor would be expected from currently-available perturbation theory analysis software. Lastly, preliminary results are shown where 127I SSNMR is used to study important supramolecular systems, and the composition of the popular synthetic reagent ‘GaI’ is elucidated.

This dissertation attempts to extend the classes of halogen-containing systems which may be studied using solid-state nuclear magnetic resonance (SSNMR). As line shape broadening due to the quadrupolar interaction (QI) scales inversely with the applied field, high-field magnet technology is indispensable for this research. Combining advanced radiofrequency pulse sequences with high-field wideline data acquisition allowed for the collection of very broad SSNMR signals of all quadrupolar halogen nuclei (i.e., 35/37Cl, 79/81Br and 127I) within a reasonable amount of experimental time. The initial systems for study were of the MX2 variety (M = Mg, Ca, Sr, Ba; X = Cl, Br, I). In total, 9 anhydrous compounds were tested. The effects of hydrate formation were tested on 7 additional compounds. Systematic trends in the observed δiso values (and to a lesser extent, Ω and CQ) were found to be diagnostic of the extent of hydration in these materials. Resolving power was successfully tested using SrBr2, which possesses 4 magnetically unique sites. The composition of CaBr2•xH2O was convincingly determined using SSNMR data and the hydration trends noted above. The sensitivity of the QI to the local bonding environment (e.g., bond distance changes of less than 0.05 Å) was used to refine (when coupled with gauge-including projector augmented-wave density functional theory (GIPAW DFT) quantum chemical computations) the structure of MgBr2, and was used to correct prior NMR data for CaCl2 (earlier accounts had been performed upon a CaCl2 hydrate). During NMR data analysis of certain iodine-containing materials, it was found that standard fitting software (which uses perturbation theory) could not reproduce the observations. Proper analysis required the use of exact simulation software and allowed for the observation of high-order quadrupole-induced effects (HOQIE). This motivated further studies using rhenium-185/187 nuclei, where it was expected that HOQIE would be more dramatic. The observed rhenium SSNMR spectra possessed additional fine structure that had never been observed before experimentally, nor would be expected from currently-available perturbation theory analysis software. Lastly, preliminary results are shown where 127I SSNMR is used to study important supramolecular systems, and the composition of the popular synthetic reagent ‘GaI’ is elucidated.

It is well known that atmospheric aerosols provide the sites for forming cloud droplets, and can affect the Earth's radiation budget through their interactions with clouds. The ability of aerosols to act as cloud condensation nuclei is a strong function of their chemical composition and size. The compositional complexity of aerosol prohibits their explicit treatment in atmospheric models of aerosol-cloud interactions. Nevertheless, the cumulative impact of organics on CCN activity is still required, as carbonaceous material can constitute up to 90% of the total aerosol, 10-70% of which is water soluble. Therefore it is necessary to characterize the water soluble organic carbon fraction by CCN activation, droplet growth kinetics, and surface tension measurements. In this thesis, we investigate the water soluble properties, such as surface tension, solubility, and molecular weight, of laboratory and ambient aerosols and their effect on CCN formation. A mechanism called Curvature Enhanced Solubility is proposed and shown to explain the apparent increased solubility of organics. A new method, called Köhler Theory Analysis, which is completely new, fast, and uses minimal amount of sample was developed to infer the molar volume (or molar mass) of organics. Due to the success of the technique in predicting the molar volume of laboratory samples, it was applied to aerosols collected in Mexico City. Additionally the surface tension, CCN activity, and droplet growth kinetics of these urban polluted aerosols were investigated. Studies performed for the water soluble components showed that the aerosols in Mexico City have surfactants present, can readily become CCN, and have growth similar to ammonium sulfate. Finally, aerosols from three different polluted sources, urban, bovine, and ship emissions, were collected and characterized. The data assembled was used to predict CCN concentrations and access our understanding of the system. From these analyses, it was evident that knowledge of the chemical composition and mixing state of the aerosol is necessary to achieve agreement between observations and predictions. The data obtained in this thesis can be introduced and used as constraints in aerosol-cloud interaction parameterizations developed for global climate models, which could lead to improvements in the indirect effect of aerosols.

Σκοπός του διδακτορικού αυτού είναι να αναδείξει τις ομοιότητες και τις διαφορές των ενεργών πυρήνων, μελετώντας το περιβάλλον γαλαξιών τύπου Sy1, Sy2, αλλά και λαμπρών υπέρυθρων γαλαξιών (BIRG, οι οποίοι ως επί το πλείστον είναι τύπου Starburst και Sy2) και συγκρίνοντας το με το περιβάλλον κανονικών μη ενεργών γαλαξιών. Διερευνάται επίσης εις βάθος, η σχέση Starburst και AGN γαλαξιών και περιλαμβάνεται η αναλυτική φασματοσκοπική μελέτη και κατηγοριοποίηση των γειτόνων των Seyfert και BIRG, σε μία προσπάθεια να βρεθεί η αναμενόμενη αμφίδρομη σχέση μεταξύ των αλληλεπιδρώντων γαλαξιών. Εν κατακλείδι, προτείνεται ένα συνολικό εξελικτικό σενάριο, που περιλαμβάνει όλους τους τύπους των ενεργών γαλαξιών που παρατηρούνται στο τοπικό σύμπαν. Το τελευταίο τμήμα της διατριβής προσεγγίζει το πρόβλημα του περιβάλλοντος των ενεργών γαλαξιών από μία διαφορετική πλευρά, αυτή των σμηνών γαλαξιών. Η ανεύρεση των ενεργών πυρήνων σε αυτή την περίπτωση γίνεται με χρήση δεδομένων ακτινών-Χ από το δορυφόρο XMM-Newton. Η ορθή ερμηνεία των αποτελεσμάτων προϋποθέτει την σύγκριση των αποτελεσμάτων με οπτικά δεδομένα, η οποία ακολουθεί σε δεύτερη φάση. / The purpose of the present thesis is to bring out the similarities and the differences of the Active Galactic Nuclei (AGN), by studying the environment of Seyfert and of Bright IRAS galaxies (BIRG, which in their majority are Starburst and Sy2 galaxies) and compare it with the environment of normal (non-active) galaxies. The Starburst/AGN connection is also studied and the spectroscopic analysis and classification of all the neighboring galaxies of Seyferts and BIRGs is included, in an attempt to find the expected bidirectional relation between interacting galaxies. We propose an evolutionary scenario, which includes all types of active galaxies present in the local universe. The last part approaches the problem from a different angle, that of the galaxy clusters. In this case the selection of the AGNs is based on their X-ray emmision, using data from the XMM-Newton satellite. Finally, we compare our findings with optical data from the Sloan Digital Sky Survey.

The anterior thalamic nuclei (ATN) are a critical part of an extended hippocampal system that supports key elements of episodic memory. Damage or disconnection of the ATN is a component of clinical conditions associated with severe anterograde amnesisa such as the Korsakoff’s syndrome, thalamic stroke, and neurodegenerative disorders. Previous studies have demonstrated that the ATN and hippocampus are often interdependent, and that ATN damage can result in ‘covert pathology’ in ostensibly healthy distal regions of the extended hippocampal system. Adult male rats with neurotoxic bilateral ATN lesions or sham surgery were post-operatively housed in an enriched environment or standard housing after a lesion-induced spatial working memory deficit had been established. These rats were retested on cross-maze and then trained in radial-arm maze spatial memory tasks. Other enriched rats received pseudo-training only after the enrichment period. The detailed neuromorphology of neurons was subsequently examined in the hippocampal CA1. Soma characteristics were also examined in the retrosplenial granular b cortex and the prelimbic cortex. In Experiment 1, ATN lesions produced clear deficits in both the cross-maze and radial-arm maze tasks and reduced hippocampal CA1 dendritic complexity, length, and spine density, while increasing the average diameter of the dendrites. Post-operative enrichment reversed the ATN lesion-induced deficits in the cross-maze and radial-arm maze, and returned CA1 basal and apical spine density to a level comparable to that of sham standard housed trained rats. The sham enriched rats exhibited improved radial-arm maze performance and increased CA1 branching complexity and spine density in both basal and apical arbors compared to sham standard housed rats. The neuromorphological changes observed in the enriched ATN and sham rats may be in part responsible for the spatial working memory improvements observed. Experiment 2 provided support for this contention by demonstrating that the CA1 spine changes were explicitly relevant to spatial learning and memory, because trained enriched sham and ATN rats had increased spines, particularly in the basal tree when compared to closely comparable pseudo-trained enriched rats. Interestingly, spatial memory training increased the numbers of both thin and mushroom spines, whereas enrichment was only associated with an increase in thin spines. In Experiment 3, ATN lesions increased cell body size in layer II of the retrosplenial granular b cortex, whereas enrichment decreased cell body size in layer V of this region. Neither ATN lesions nor enrichment had any effect on cell body morphology in the prelimbic cortex. The current research provides some of the strongest evidence to date of ATN and hippocampal interdependence within the extended hippocampal system, and provides the first evidence of neuromorphological correlates of recovery after ATN lesions.