Natural Scene Statistics (NSS) provide powerful perceptually relevant tools that have been successfully used for image quality analysis of visible light images. NSS capture statistical regularities that arise in the physical world and thus are relevant to Long Wave Infrared (LWIR) images. LWIR images are similar to visible light images and mainly differ by the wavelengths captured by the sensors. The distortions unique to LWIR are of particular interest to current researchers. We analyze a few common LWIR distortions and how they relate to NSS models. Humans are the most important factor for assessing distortion and quality in IR images, which are often used in perceptual tasks. Therefore, predicting human performance when a task involving LWIR images needs to be performed can be critical to improving task efficacy. The National Institute for Standards and Technology (NIST) characterizes human Targeting Task Performance (TTP) by asking firefighters to identify the locations of fire hazards in LWIR images under distorted conditions. We find that task performance can be predicted using NSS features. We also report the results of a human study. We analyzed the NSS of LWIR images under pristine and distorted conditions using four databases of LWIR images. Each database was captured with a different camera allowing us to better evaluate the statistics of LWIR images independent of camera model. We find that models of NSS are also effective for measuring distortions in the presence of other independent distortions. / text

O arbovírus Oropouche (OROV), da família Peribunyaviridae, gênero Orthobunyavirus, é importante causador de doença febril nas Américas Central e do Sul. Como outros Orthobunyavirus, OROV é envelopado, com genoma compreendido por três segmentos de RNA de fita simples de polaridade negativa, nomeados de acordo com o seu tamanho, como S (small), M (médio) e L (large). O segmento S codifica a proteína estrutural do nucleocapsideo N e, em uma fase de leitura alternativa, a proteína não estrutural NSs. Apesar da patogênese de OROV ser pouco conhecida, dados obtidos com modelos experimentais murinos indicam que a apoptose desempenha um papel central na morte de células infectadas. Portanto, embora não seja essencial à replicação de OROV, NSs pode desempenhar papeis importantes para a patogênese. Nosso grupo demonstrou previamente que OROV induz apoptose em células HeLa pela via intrínseca, e esse efeito requer a síntese de proteínas virais. No presente estudo objetivamos investigar o papel da proteína NSs de OROV na apoptose induzida em células HeLa. Nós encontramos que a superexpressão da proteína NSs de OROV induz apoptose em diferentes linhagens de células humanas (Glioblastoma, Huh7 e HCE) 24 horas após transfecção. NSs induz apoptose pela via intrínseca, com liberação de citocromo c da mitocôndria, ativação de caspases 9 e 3, e fragmentação de cromatina. Curiosamente, a proteína NSs também induz apoptose pela via extrínseca, confirmada pela detecção de caspase 8 ativada. Um clone infeccioso do OROV sem a proteína NSs (OROVdelNSs) também não induz apoptose em células HeLa até 36 horas pós-infecção, confirmando a importância da proteína NSs para a indução de morte celular por apoptose. A predição da estrutura da proteína NSs revelou a presença de uma sequência de treze aminoácidos na região C-terminal da proteína, que tem similaridade como receptor de TNF. Ensaio de PCR array indicou que a proteína NSs de OROV causa aumento na quantidade de transcritos de TNF em células HeLa. / The arbovirus Oropouche (OROV), of the family Peribunyaviridae, genus Orthobunyavirus, is an important cause of febrile disease in Central and South America. Like other Orthobunyaviruses, OROV is enveloped, with a genome comprised of three segments of single-stranded RNA of negative polarity, named according to their sizes as S (small), M (medium) and L (large). The S segment encodes the structural nucleocapsid N protein and, on an alternative reading frame, the NSs nonstructural protein. Although the pathogenesis of OROV is poorly understood, data obtained from murine experimental models indicate that apoptosis plays a central role in killing infected cells. Therefore, while not essential for the replication of OROV, NSs may play important roles in the pathogenesis. Our group has previously demonstrated that OROV induces apoptosis in HeLa cells via the intrinsic pathway, and this effect requires the synthesis of viral proteins. The present study aimed to investigate the role of OROV protein NSs in apoptosis induced in HeLa cells. We found that overexpression of the NSs protein induces apoptosis in different human cell lines (glioblastoma neuroblastoma and human corneal epithelium) 24 hours after transfection. NSs induces apoptosis by the intrinsic pathway, with release of cytochrome c from mitochondria, activation of caspases 9 and 3, and chromatin fragmentation. Interestingly, the NSs protein also induces activation of caspase 8, an element of the extrinsic pathway of apoptosis. An OROV infectious clone lacking the NSs protein (OROVdelNSs) does not induce apoptosis in HeLa cells up to 36 hours postinfection, confirming the importance of the NSs protein for the induction of cell death by apoptosis. The prediction of the structure of the NSs protein revealed the presence of a sequence of thirteen amino acids in the C-terminal region of the protein, which has similarity as a TNF receptor, and this could shed light into a possible mechanism of apoptosis to be validated by experiments silencing target genes in Hela cells.

O arbovírus Oropouche (OROV), da família Peribunyaviridae, gênero Orthobunyavirus, é importante causador de doença febril nas Américas Central e do Sul. Como outros Orthobunyavirus, OROV é envelopado, com genoma compreendido por três segmentos de RNA de fita simples de polaridade negativa, nomeados de acordo com o seu tamanho, como S (small), M (médio) e L (large). O segmento S codifica a proteína estrutural do nucleocapsideo N e, em uma fase de leitura alternativa, a proteína não estrutural NSs. Apesar da patogênese de OROV ser pouco conhecida, dados obtidos com modelos experimentais murinos indicam que a apoptose desempenha um papel central na morte de células infectadas. Portanto, embora não seja essencial à replicação de OROV, NSs pode desempenhar papeis importantes para a patogênese. Nosso grupo demonstrou previamente que OROV induz apoptose em células HeLa pela via intrínseca, e esse efeito requer a síntese de proteínas virais. No presente estudo objetivamos investigar o papel da proteína NSs de OROV na apoptose induzida em células HeLa. Nós encontramos que a superexpressão da proteína NSs de OROV induz apoptose em diferentes linhagens de células humanas (Glioblastoma, Huh7 e HCE) 24 horas após transfecção. NSs induz apoptose pela via intrínseca, com liberação de citocromo c da mitocôndria, ativação de caspases 9 e 3, e fragmentação de cromatina. Curiosamente, a proteína NSs também induz apoptose pela via extrínseca, confirmada pela detecção de caspase 8 ativada. Um clone infeccioso do OROV sem a proteína NSs (OROVdelNSs) também não induz apoptose em células HeLa até 36 horas pós-infecção, confirmando a importância da proteína NSs para a indução de morte celular por apoptose. A predição da estrutura da proteína NSs revelou a presença de uma sequência de treze aminoácidos na região C-terminal da proteína, que tem similaridade como receptor de TNF. Ensaio de PCR array indicou que a proteína NSs de OROV causa aumento na quantidade de transcritos de TNF em células HeLa. / The arbovirus Oropouche (OROV), of the family Peribunyaviridae, genus Orthobunyavirus, is an important cause of febrile disease in Central and South America. Like other Orthobunyaviruses, OROV is enveloped, with a genome comprised of three segments of single-stranded RNA of negative polarity, named according to their sizes as S (small), M (medium) and L (large). The S segment encodes the structural nucleocapsid N protein and, on an alternative reading frame, the NSs nonstructural protein. Although the pathogenesis of OROV is poorly understood, data obtained from murine experimental models indicate that apoptosis plays a central role in killing infected cells. Therefore, while not essential for the replication of OROV, NSs may play important roles in the pathogenesis. Our group has previously demonstrated that OROV induces apoptosis in HeLa cells via the intrinsic pathway, and this effect requires the synthesis of viral proteins. The present study aimed to investigate the role of OROV protein NSs in apoptosis induced in HeLa cells. We found that overexpression of the NSs protein induces apoptosis in different human cell lines (glioblastoma neuroblastoma and human corneal epithelium) 24 hours after transfection. NSs induces apoptosis by the intrinsic pathway, with release of cytochrome c from mitochondria, activation of caspases 9 and 3, and chromatin fragmentation. Interestingly, the NSs protein also induces activation of caspase 8, an element of the extrinsic pathway of apoptosis. An OROV infectious clone lacking the NSs protein (OROVdelNSs) does not induce apoptosis in HeLa cells up to 36 hours postinfection, confirming the importance of the NSs protein for the induction of cell death by apoptosis. The prediction of the structure of the NSs protein revealed the presence of a sequence of thirteen amino acids in the C-terminal region of the protein, which has similarity as a TNF receptor, and this could shed light into a possible mechanism of apoptosis to be validated by experiments silencing target genes in Hela cells.

Rift Valley fever virus (RVFV) is a Phlebovirus member of the Bunyaviridae family and it is the causative agent of Rift Valley fever (RVF), a mosquito-borne viral zoonotic disease that poses a significant threat to domestic ruminants and human health in Africa. The RVFV is an encapsulated, negative-sense, single-stranded RNA virus with a tripartite segmented genome, containing L (large), M (medium) and S (small) segments. The S segment codes for two proteins, namely the nucleocapsid (N) protein and non-structural protein (NSs). There is evidence that the NSs protein is involved in virulence by blocking the expression of the interferon beta (IFN-β) promoter. It has been recently demonstrated that the SAP30-NSs-YY1 multiprotein complex represses the IFN-β promoter. Consequently, the interferon expression is blocked, allowing virus to replicate. A total of 45 isolates of RVFV recovered over a period of 53 years in 14 African countries, Madagascar and Saudi Arabia were characterized by full sequencing of the S segment of the virus. This data was added to another 27 strains of RVFV available on GenBank for phylogenetic analysis using MEGA4, giving a total of 72 strains analyzed. Alignments were made of the entire S segment, the NSs gene, the N gene, and their deduced amino acid sequences. The laboratory strains, clone 13, MP12 and Smithburn, were also included in the alignments. Two isolates were passaged ten times through two different amplification systems to asses the potential for sequence variation to occur in the original material through routine laboratory manipulations. Sequencing data was generated from the virus RNA present in the original clinical specimens and from the extracted RNA from the tenth passage of virus in each amplification system. The results showed 100% homology for each respective isolate, demonstrating that the RVFV S segment remained stable during ten serial passages in different propagation systems. Phylogenetic analysis was conducted on the naturally occurring RVFV strains (n = 72) and the findings indicate that circulating strains are compartmentalized and belong to one of three major lineages, namely Egyptian, western African, and central, eastern and southern African. The strains clustered in the Egyptian lineage had an average p-distance of 1.0%, the western African strains 0.9%, and the central, southern and eastern African strains 2.0%. The overall average p-distance was 2.5%, with a range from 0 to 4.1%. For the N gene, the range was from 0 to 4.2%, with an average of 2.2%. For the N protein, the range was from 0 to 2%, with an average of 0.2%. The NSs gene had a range of 0 to 4.6%, with an average of 2.4%. The NSs protein had a range of 0 to 3.8%, with an average of 1.7%. The intergenic region (IGR) had a range of 0 to 9.2%, with an average of 4.8%. Results of the study suggest that RVF outbreaks can result from either the rapid spread of a single strain over vast distances or from an increased activity of a strain circulating at an endemic level within an area/region during prolonged dry periods. Sequencing alignment showed that the length of the S segment ranged from 1690 to 1692 nucleotides. This difference in length was due to insertions and deletions found in the IGR, which is also the region with the most sequence divergence (4.8%). Both the NSs and N genes had neither insertions nor deletions, and were both found to be stable, though the NSs gene was slightly more variable than the N gene (2.5% versus 2.2%) The deduced amino acid sequences of the NSs protein were considerably more variable than that of the N protein (1.7% versus 0.2%). Alignment of the NSs protein demonstrated that the 5 cysteine residues at positions 39, 40, 150, 179 and 195, are highly conserved among the isolates analyzed. These residues are important for conservation of the three-dimensional structure of the protein and the formation of filamentous structures observed in cells infected with natural strains of RVFV. The NSs protein is now implicated as the major factor of virulence and that its pathogenicity is associated with the blocking of interferon production. Therefore, any amino acid changes that result in changes to the filamentous structure of the NSs protein might impact on the binding kinetics between the NSs protein, SAP30 (Sin3A Associated Protein 30) and YY1 (Yin Yang-1). There were 6 amino acid changes in the NSs-SAP30 binding domain, with one being unique to the live-attenuated Smithburn vaccine strain. Generated sequencing data contributes to global phylogenetic characterization of RVFV isolates and and molecular epidemiology of the virus. In addition, findings of this study will further aid investigation on reassortment events occurring between strains of RVFV and genetically related viruses, the role of the NSs protein in the replicative cycle of the virus, the pathogenic effects of the NSs protein within the RVFV-infected host cells, and might help to identify molecular basis of RVFV virulence.

Introduction : En 2011, un arbovirus émergent appelé virus Schmallenberg (SBV) et appartenant à la famille des Bunyaviridae a été identifié en Allemagne et s’est répandu en Europe. Le SBV infecte les ruminants domestiques et sauvages. Chez l’adulte, la virémie est transitoire et l’infection est souvent inapparente. En revanche, chez les femelles gestantes, le SBV peut franchir la barrière transplacentaire et infecter le fœtus, pouvant provoquer des avortements et des malformations du système nerveux central. Parmi les protéines virales synthétisées par le SBV, la protéine non-structurale NSs est un facteur de virulence majeur. Elle entraîne notamment la dégradation de sa sous-unité Rpb1 de l’ARN polymérase II pour inhiber la transcription cellulaire. Ce travail a pour but d’étudier les propriétés biochimiques et fonctionnelles de NSs et d’identifier les déterminants moléculaires régissant ses principales activités.Méthodes et résultats: L’analyse in silico de la séquence peptidique de NSs réalisée à l’aide d’algorithmes de prédiction a permis de designer plusieurs de mutants de délétion de la protéine. L’observation de la localisation cellulaire des mutants dans plusieurs modèles humains et ovins confirme la prédiction d’une distribution principalement nucléaire pour NSs. De façon intéressante, une séquence interne à la protéine (33-51) sert de motif d’adressage spécifique au niveau des nucléoles (NoLS) et nous avons pu démontrer la co-localisation de NSs avec plusieurs protéines nucléolaires. De plus, l’infection de cellules humaines et ovines par le SBV entraîne la translocation de protéines nucléolaires (B23 et fibrillarine) vers le nucléoplasme, témoignant d’un stress nucléolaire viro-induit. Pour évaluer l’impact de la localisation nucléolaire de NSs sur ce phénomène, un virus recombinant dont NSs a été délétée de son motif d’adressage nucléolaire (SBVΔNoLS) a été produit par génétique inverse. Le SBVΔNoLS n’induit plus de redistribution de B23 confirmant le rôle de NSs dans l’induction d’un stress nucléolaire au cours de l’infection. Ces résultats ont été confirmés dans des cellules souches neurales humaines, qui constituent un modèle pertinent par rapport aux lésions provoquées par le SBV dans le système nerveux.En parallèle de ce travail, nous avons recherché des partenaires cellulaires de NSs par la méthode du double-hybride en levures. Huit partenaires cellulaires de NSs ont été découverts, dont la chaîne légère de la dynéine de type 1 (Tctex-1) et la Major Vault Protein (MVP), qui sont toutes les deux impliquées dans le transport de protéines grâce à leur association aux microtubules. Une des hypothèses avancées est que ces protéines pourraient servir de cargos pour promouvoir le transport nucléo-cytoplasmique de NSs.Conclusions et perspectives : Ce travail de thèse a permis de démontrer que la protéine NSs du SBV est localisée principalement dans le noyau cellulaire et dans les nucléoles, grâce à une séquence d’adressage spécifique. L’infection virale induit un stress nucléolaire dépendant de NSs, qui a pu être reproduit dans un modèle de cellules souches neurales humaines. Les perturbations nucléolaires induites par NSs pourraient contribuer au blocage de la transcription cellulaire observé au cours de l’infection et, de manière subséquente, moduler la réponse antivirale de la cellule et/ou induire la mort cellulaire en lien avec la pathogenèse virale. Ainsi, ces perturbations des nucléoles pourraient être à l’origine d’une dégénérescence des neurones et des anomalies développementales observées chez les fœtus infectés. Au niveau moléculaire, nous souhaitons préciser l’implication de la protéine nucléolaire B23, relocalisée vers le nucléoplasme en cours d’infection, et/ou d’autres composants du nucléole dans l’initiation de ce processus. Enfin, l’hypothèse d’un transport rétrograde actif de NSs du cytoplasme vers le noyau médié par son interaction avec MVP ou Tctex1 est en cours d’investigation. / Introduction: In 2011, an emerging arbovirus named Schmallenberg virus (SBV), and belonging to the Bunyaviridae family, was discovered in Germany. Then, SBV has rapidly spread to Europe infecting wild and domestic ruminants. Adult infection is basically mild and associated with a short viremia (2-5 days). However, in case of pregnant females’ infection, SBV has the ability to cross the placental barrier to infect the foetuses, which can lead to stillbirth and central nervous system developmental abnormalities (arthrogyposis, hydranencephaly). Among bunyavirus-encoded proteins, the non-structural protein NSs has been shown to be an important virulence factor. Indeed, it is able to degrade the Rpb1 subunit of RNA polymerase II, leading to the inhibition of cellular transcription. The work of my thesis aimed to study biochemical and functional properties of NSs and to identify the molecular patterns ruling its main activities.Methods and results: An in silico amino acids sequence analysis was used to predict some common features of NSs and to help the design of several NSs mutants. As predicted by several algorithms, NSs and its mutants are mainly localised to cell nucleus in different cell types (from human and ovine origin). Interestingly, we highlighted an internal sequence (residues 33 to 51) containing a nucleolar localisation signal (NoLS), and have shown that NSs co-localises with several nucleolar proteins. Moreover, infections of human and ovine cell lines with SBV lead to re-localisation of nucleolar proteins to nucleoplasm (B23 and fibrillarin), demonstrating a viral-induced nucleolar stress. To assess the role of the NSs nucleolar localisation in this phenomenon, a recombinant virus, with a mutated version of NSs devoid of its NolS motif (SBVΔNoLS), was constructed by reverse genetic. Infection with SBVΔNoLS does not induce nucleolar stress, suggesting that the nucleolar stress induced by SBV occurs only if NSs is addressed to the nucleolus. Moreover, these results have been confirmed in human neural stem cells, which coud be a more relevant cellular model to mimic SBV infection in foetuses.Another way to study NSs functions was to identify its cellular partners by means of a yeast-two hybrid screen and using NSs as bait. Eight putative interactors of NSs have been discovered, including the dynein light chain type 1 (Tctex-1) and the Major Vault protein (MVP). These proteins are involved in cellular protein transport, notably by their associations with the microtubules network. Thus, NSs might interact with Tctex-1 and MVP to favour its shuttling from cell cytoplasm to the nucleus.Conclusions and perspectives: Altogether, these data indicate that SBV-NSs protein is mainly localised into cell nucleus and nucleolus, by means of its internal NoLS contained in the 33-51 NSs domain. SBV infection induces a nucleolar stress, particularly in human neural stem cells. NSs-induced nucleolar disruption could promote NSs inhibitory function on cellular transcription, and subsequently modulate cellular antiviral state and/or induce cell death. Regarding the pathogenesis in SBV-infected foetuses, nucleolar stress could be responsible for neurons degeneration and subsequent developmental abnormalities. At molecular level, our aim is to define the role of nucleolar protein B23 on viral replication, which is strongly relocalised to the nucleoplasm during SBV infection. Finally, hypothesis of NSs retrograde transport from cell cytoplasm to nucleus and the possible contributions of MVP and/or Tctex-1 needs to be further investigate.

Hyperacusis is a condition that is described by abnormal reactions to ordinary sounds, however, because of its complexity and newness, this diagnosis still lacks centralized definition and established prevalence rates. Previous research has attempted to define the condition and establish measurements. The Noise Sensitivity Scale (NSS) has been examined several times and new questionnaires have been produced, one being Umeå Hyperacusis Questionnaire (UHQ) produced by Paulin et al. (2019). The latter has not been analyzed in regards to its ability to measure hyperacusis. The current study used exposure data from Paulin et al. (2019) to compare UHQ and NSS abilities to measure the different elements of hyperacusis; the study aimed to a) compare ratings of intensity, concentration, and unpleasantness between UHQ and NSS; b) determine the validity of UHQ. The sample consisted of 64 participants and analyses conducted were linear regression, logistic regression, factor analysis and repeated measures ANOVA. The results indicate that UHQ was greater at measuring intensity, while NSS more accurately measured unpleasantness and concentration. The abilities of the former differed when time was taken in consideration and showed significance in relation to unpleasantness across the lab exposure. The studies suggest that future research should investigate and include more elements that constitute hyperacusis and attempt to increase the sample size. / Hyperacusis är ett tillstånd som karaktäriseras av onormala reaktioner på vanliga ljud, men på grund av att diagnosen är relativt ny och med komplex sjukdomsbild saknas det fortfarande en centraliserad definition och fastställd prevalens. Tidigare forskning har arbetat med att definiera konceptet och utveckla mätinstrument; Noise Sensitivity Scale (NSS) har brukats i flertalet studier och nya enkäter har skapats, bland annat Umeå Hyperacusis Questionnaire (UHQ) av Paulin et al; UHQ har inte analyserats avseende dess förmåga att tillförlitligt mäta hyperacusis. Denna studie använde exponeringsdata från Paulin et al. (2019) för att jämföra UHQ och NSS med avseende på att mäta de olika elementen i hyperacusis. Studien syftade till att a) jämföra självuppskattning av intensitet, koncentration och obehag mellan UHQ och NSS; b) fastställa validitet av UHQ. Urvalet bestod av 64 deltagare och genomförda analyser var linjär regression, logistisk regression, faktoranalys och repeated measures ANOVA. Resultaten visade att UHQ var bättre på att mäta intensitet, medan NSS var lämpligare att mäta obehag och koncentration. UHQs förmåga att mäta obehag skilde sig när tid togs i beaktande och blev då signifikant. Framtida forskning borde undersöka och inkludera fler element som utgör hyperacusis och försöka öka urvalsstorlek.

京都大学 / 新制・課程博士 / 博士(生命科学) / 甲第23440号 / 生博第461号 / 新制||生||61(附属図書館) / 京都大学大学院生命科学研究科統合生命科学専攻 / (主査)教授 野田 岳志, 教授 朝長 啓造, 教授 千坂 修 / 学位規則第4条第1項該当 / Doctor of Philosophy in Life Sciences / Kyoto University / DFAM

Environmental scientists use ice-core records to reconstruct past atmospheric conditions. Anthropogenic and natural sources of emissions can be traced when analyzing ions in the ice, which is included in the science of glaciochemistry. Sulfate is an excellent ion to use in these studies since it is traceable to these emissions. This study is therefore focused on the sulfate ion, how its concentration has fluctuated over the last 200-years and when a change of trend occurred. The ice-cores used in this study were extracted at Lomonosovfonna, Svalbard, and analyzed by Ion Chromatography (IC). The new data that has been brought forth in this study covers nss-SO42- concentrations in the years of 1998-2012 and is connected to previous extracted ice-core records. The results of nss-SO42- concentration in the ice-cores confirm the change of trend in the 1970s. The increasing trend in the result correlate with historical emissions and the decrease after the change of trend enhances less anthropogenic impact on the atmosphere. / Miljöforskare använder sig av isborrkärnor för att återskapa tidigare atmosfäriska förhållanden. Antropogena och naturliga utsläppskällor kan spåras genom att analysera joner i isen. Sulfat är en utmärkt jon att använda sig av i dessa studier, eftersom den kan anknytas till dessa utsläpp. Denna studie fokuserar därför på sulfatjonen, hur dess koncentration har ändrats under de senaste 200-åren och på det trendbrott som har ägt rum. Isborrkärnorna som har använts i denna studie borrades upp på Lomonosovfonna, Svalbard, och analyserades med jonkromato-grafi. Ny data som har tagits fram i den här studien täcker nss-SO42- koncentrationen mellan 1998-2012 och är sammankopplad med tidigare framtagen data från samma plats. Resultatet av nss-SO42- koncentrationen i isborrkärnorna bekräftar trendbrottet som inträffade på 1970-talet. Den ökande trenden i resultatet korrelerar med historiska utsläpp och minskningen efter trendbrottet påvisar mindre antropogen påverkan på atmosfären.

Dimethyl Sulfide (CH3SCH3, DMS) is the most important natural sulfur compound emitted from the ocean and its oxidation in the atmosphere has been proposed to play an important role in climate modification because some products from DMS oxidation become non-volatile and could participate in particle formation and growth processes. Although it has been demonstrated that aqueous phase reactions are potentially important for understanding DMS oxidation, the kinetics database for aqueous phase transformations is rather limited. In this work, a laser flash photolysis (LFP) ??ng path UV-visible absorption (LPA) technique was employed to investigate the kinetics of the aqueous phase reactions of four organic sulfur compounds produced from DMS oxidation, i.e., dimethylsulfoxide (DMSO), dimethyl-sulfone (DMSO2), methanesulfinate (MSI) and methanesulfonate (MS), with four important aqueous phase radicals, OH, SO4 and #8722;, Cl and Cl2 and #8722;. The temperature-dependent kinetics of the OH and SO4 and #8722; reactions with DMSO, DMSO2 and MS were studied for the first time. OH is found to be the most reactive, while Cl2 and #8722; is the least reactive toward all the sulfur species studied. The less oxidized DMSO and MSI are found to be more reactive than the more oxidized DMSO2 and MS for each radical. The kinetic data have been employed in a Trajectory Ensemble Model to simulate DMS oxidation in the marine atmosphere as a means of assessing the contribution of aqueous phase reactions to the growth of particulate matter. For the first time, oxidation of organic sulfur compounds by SO4 and #8722;, Cl and Cl2 and #8722; are included in the model to simulate DMS chemistry. Our simulations suggest that aqueous phase reactions contribute >97% of MS and ~90% of NSS (Non-Seasalt Sulfate) production, and aqueous phase reactions of the organic sulfur compounds contribute 30% of total particle mass growth. When our kinetic data for the MS + OH reaction were used in the model, it was found that MS + OH could consume ~20% of MS and produce ~8% of NSS, within 3 days under typical marine atmospheric conditions.

Natural scene statistics (NSS) have played an increasingly important role in both our understanding of the function and evolution of the human vision system, and in the development of modern image processing applications. Because depth/range, i.e., egocentric distance, is arguably the most important thing a visual system must compute (from an evolutionary perspective), the joint statistics between natural image and depth/range information are of particular interest. However, while there exist regular and reliable statistical models of two-dimensional (2D) natural images, there has been little work done on statistical modeling of natural luminance/chrominance and depth/disparity, and of their mutual relationships. One major reason is the dearth of high-quality three-dimensional (3D) image and depth/range database. To facilitate research progress on 3D natural scene statistics, this dissertation first presents a high-quality database of color images and accurately co-registered depth/range maps using an advanced laser range scanner mounted with a high-end digital single-lens reflex camera. By utilizing this high-resolution, high-quality database, this dissertation performs reliable and robust statistical modeling of natural image and depth/disparity information, including new bivariate and spatial oriented correlation models. In particular, these new statistical models capture higher-order dependencies embedded in spatially adjacent bandpass responses projected from natural environments, which have not yet been well understood or explored in literature. To demonstrate the efficacy and effectiveness of the advanced NSS models, this dissertation addresses two challenging, yet very important problems, depth estimation from monocular images and no-reference stereoscopic/3D (S3D) image quality assessment. A Bayesian depth estimation framework is proposed to consider the canonical depth/range patterns in natural scenes, and it forms priors and likelihoods using both univariate and bivariate NSS features. The no-reference S3D image quality index proposed in this dissertation exploits new bivariate and correlation NSS features to quantify different types of stereoscopic distortions. Experimental results show that the proposed framework and index achieve superior performance to state-of-the-art algorithms in both disciplines. / text