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Les élements présents a l'état de traces et les Hydrocarbures Aromatiques Polycycliques dans la neige et la glace prélevées au Col Gnifetti, massif du Mont Rose (4450m): implications environnementales et climatiquesGabrieli, Jacopo 28 November 2008 (has links) (PDF)
Nous avons conçu, construit et testé un nouveau système pour la décontamination en ligne et l'analyse en continu de carottes de neige ou de glace des Alpes. L'eau de fusion obtenue à partir de la partie centrale des carottes est directement introduite dans un spectromètre de masse à quadrupole (ICP-QMS) et un conductimètre, pour la détermination en continu de différents éléments présents à l'état de traces et de la conductivité. Des échantillons sont également prélevés en discontinu pour la détermination de divers éléments présents à l'état de traces, des isotopes du Plomb et du Plutonium par spectrométrie de masse à secteur magnétique (ICP-SFMS) et par ICP-OES. L'eau de fusion obtenue à partir de la partie externe des carottes est quant à elle utilisée pour la détermination en semi-continu des Hydrocarbures Aromatiques Polycycliques (HAPs), avec extraction en ligne à l'aide de cartouches en phase solide.<br />D'importantes variations saisonnières des concentrations sont observées pour tous les éléments, aussi bien les éléments qui proviennent de manière prédominante de la croûte terrestre (Mg, Al) que les éléments enrichis par suite d'apports anthropiques (Pb). Pour comprendre ces variations à court terme, il est important de se référer aux rétro-trajectoires des masses d'air. D'autres paramètres importants sont la dynamique des inversions de températures et les caractéristiques de la couche limite. Ils jouent en effet un rôle majeur dans le transport et la dispersion des aérosols et des gaz à partir des sources d'émissions situées à basse altitude.<br />Les émissions les plus importantes de Plomb au cours de l'histoire ont eu lieu pendant les 19e et 20e siècles, et plus particulièrement des années 1950 aux années 1970. Pour déterminer si les variations observées dans la carotte du Colle Gnifetti reflètent fidèlement les variations des émissions dans les pays européens voisins, nous avons comparé les données obtenues pour la neige et la glace avec les données d'émission disponibles. De 1800 jusqu'à la première décennie du 20e siècle, les concentrations de Plomb ont augmenté de manière très marquée, atteignant un maximum dans les années 1920. Pendant les années 1920, les concentrations de Plomb décroissent rapidement d'un facteur deux, et restent à ce niveau pendant les deux décennies suivantes. Après la fin de la 2e guerre mondiale, les flux de retombées de Plomb augmentent de manière très importante par suite de l'utilisation des additifs au Plomb dans l'essence, et atteignent un maximum au milieu des années 1970. A partir de 1975, les concentrations de Plomb mesurées dans la neige et la glace du Colle Gnifetti commencent à décroître par suite des règlementations adoptées en Europe pour limiter les émissions de polluants.<br />Avant 1875, les concentrations de HAP étaient très basses: les concentrations observées dans la glace datant d'avant les années 1750 représentent très probablement le niveau de bruit de fond de ces composés. Les concentrations cumulées des HAP au cours de la décennie 1945-1955 sont supérieures d'un facteur dix aux valeurs de bruit de fond, alors que les concentrations cumulées de HAP* sont environ 40 à 50 fois plus élevées. A partir des années 1900, les concentrations de HAP augmentent de façon très importante, atteignant un maximum vers 1920. Pendant les années 1920, après la première guerre mondiale, la récession économique en Europe conduit à une chute des activités industrielles. A partir du milieu des années 1930, les concentrations de HAP doublent rapidement, atteignant un maximum pendant les années 1940. La concentration cumulée des HAP* les plus lourds décroit ensuite d'un facteur cinq de 1950 à 1975 alors que la concentration cumulée des HAP décroit d'un facteur deux. De 1975 à 2003, la concentration totale des HAP augmente à nouveau, approchant les valeurs des années 1910. De manière globale, les variations temporelles observées pour les HAP sont fortement corrélées aux variations des émissions anthropiques. Cependant, les variations détaillées sont difficiles à interpréter et pourraient être influencées par divers paramètres.<br />Le Plutonium est présent dans l'environnement par suite des essais nucléaires atmosphériques des années 1960, de la production des armes nucléaires et des rejets par l'industrie nucléaire au cours des 50 dernières années. Le profil de variations du Plutonium dans la neige et la glace du Colle Gnifetti met en évidence les trois périodes principales d'essais nucléaires atmosphériques.<br />Le rapport isotopique 206Pb/207Pb est compris entre 1.18 et 1.20 pour la glace datant d'avant 1700, en accord avec la composition des roches locale. Bien que les retombées de Plomb au Colle Gnifetti après les années 1900 soient presque entièrement dues à des apports anthropiques, on n'observe pas de variations importantes du rapport isotopique jusqu'en 1975. Ceci est lié au fait que la composition isotopique moyenne du Plomb dans l'essence et le pétrole utilisés était très semblable à la composition isotopique des roches et des sols locaux. Après 1975, on observe une décroissance brutale et forte du rapport isotopique 206Pb/207Pb, jusqu'à des valeurs proches de 1.11 en 1979-1980. Cette décroissance brutale est liée à une expérience réalisée entre 1975 et 1980 dans la région du Piémont au Nord-Ouest de l'Italie (Isotopic Lead Experiment).
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Assessment of Environmental Pollutants in Humans from Four Continents : Exposure levels in Slovakia, Guinea-Bissau, Nicaragua and BangladeshLinderholm, Linda January 2010 (has links)
Humans are continuously exposed to complex mixtures of anthropogenic chemicals. This thesis focus on human exposure to persistent organic pollutants (POPs). POPs ability to bioaccumulate and biomagnify together with the extensive historical use of POPs in e.g. agriculture and industry have resulted in detection of these compounds in humans and animals from all over the world. Adverse health effects caused by POPs are of particular concern for newborns and young individuals. The objective of this thesis is to assess human exposure to a selected set of POPs and their metabolites. More specifically, one aim of my thesis is to determine the exposure to polychlorinated biphenyls (PCBs) and in particular their methylsulfonyl and hydroxylated metabolites in humans from a “hot-spot” area of PCB contamination in eastern Slovakia. The maternal transfer of these chemicals is studied. Further, another specific aim is to determine occurrence, levels and, when possible, temporal trends of POPs in children and adults from three developing countries, Nicaragua, Guinea-Bissau and Bangladesh. High concentrations of PCBs and their metabolites are shown in men and women from Michalovce in eastern Slovakia. Placental transfer of methylsulfonyl-metabolites of PCBs and 4,4’-DDE was observed for the first time. Decreasing temporal trends of the majority of POPs are shown in serum from a cohort of policemen from Guinea-Bissau. In contrast, the levels of polybrominated diphenyl ethers (PBDEs) show an increasing time trend. Within five years, decreasing levels of POPs were also shown in children working and living at a waste disposal site in Nicaragua. Children working and living at waste disposal sites in Bangladesh have considerably lower levels of POPs compared to the children from Nicaragua except for 4,4’-DDT and 4,4’-DDE that are present at very high concentrations, indicating ongoing use of technical DDT. There are many studies on levels and trends of environmental pollutants from the developed industrial countries in the world, whereas data from developing countries is still scarce. This thesis contributes to partly fill this data gap since it includes assessments of POPs in children and adults from four countries on four continents. / At the time of doctoral defense, the following papers were unpublished and had a status as follows: Paper 5: Manuscript. Paper 6: Manuscript.
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The Types of Perception of Organizational Politics and the reason of the types of perception of Organizational PoliticsYang, Szu-Chi 26 August 2003 (has links)
Abstract
Political behavior in organization is undeniable, while studies of organizational politics lasting for recent decades had accumulated abundant understanding in this area. However, there are still many arguments against this complex subject needed further research. The purpose of the research is 1) to test and verify the input model of Organizational Politics Perception Model¡C 2) to test the effectiveness and reliability and solve the controversy of dimensions of POPS ¡C 3) to further refine the input model by type analysis and try to explain the cause of Organizational Politics Perceptions¡C
For research procedure and sample: Participants were 973 and drawn from Hospital¡Bprivate and public service firms¡Btraditional manufacturing and high-technical firms¡CThe research method is descriptive statistics analysis¡B reliability analysis¡Bfactor analysis¡Bregression analysis¡Bone-way ANOVA and cluster analysis¡C
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The reason formed of Perception of Organization Politics and the effects of Perception of Organization Politics on Organizational Citizenship Behavior. ¡V A Study of T CompanyLin, Wei-Chih 28 August 2004 (has links)
This investigation uses the model proposed by Ferris et al.¡]1989¡^, the sample consisted of 802 employees selected from a big organizations in Taiwan. The data were analyzed by applying statistical methods, including factor analysis, reliability, correlation and multiple linear regressions. The process of study was divided into two stages and carry on real example analysis and accordance with the analysis result to offer management suggestions. In the first stage, studying the relationships among the perceptions of organizational politics , employee¡¦s personal influences¡Morganizational influences¡Mjob/work environment influences in T company. In the second stage, studying the relationships among the perceptions of organizational politics and organizational citizenship within T Company.
The results of this study in summary are:
1. Personal factor has effects on POPs with respect to all its three dimensions.
2. Organizational factor has effects on POPs with respect to all its three dimensions.
3. POPs has effects on Organizational Citizenship Behavior with respect to all its three dimensions.
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Occurrence, Distribution And Sources Of Polychlorinated Biphenyls At Selected Industrial Sites In TurkeyGedik, Kadir 01 June 2010 (has links) (PDF)
In this study, the occurrence and distribution of polychlorinated biphenyls (PCBs) were investigated via sampling studies conducted around a thermal power plant (Seyitö / mer, Kü / tahya), a scrap metal yard (Kizilirmak, Kirikkale), transformer repair and maintenance facility (Lake Eymir, Ankara), and two organized industrial districts (izmit and Mersin), and 120 samples composed mainly of sediments were collected from those sites.
Total PCBs ranged from not detected to 385 ng/g for all samples. Analysis of samples indicates enrichment of PCBs with special emphasis to sediments collected around the Seyitö / mer thermal power plant. Congener specific results indicate domination of profiles by penta- and hexa-chlorobiphenyls. Overall, the PCB concentrations observed in sampling sites are comparable to the background levels of soil/sediments around the world.
To identify relevant pollution sources, congener specific data were further evaluated in the subsequent process of source apportionment using Chemical Mass Balance (CMB) receptor model. A general overview of the source apportionment results indicate that equipments (transformers and capacitors) mainly used in the energy generation/transmission and high energy consuming industries as the major PCB sources. PCBs used in open applications were also predicted as sources depending on site characteristics.
Overall, indications of contaminated sites are evident in a number of locations / yet, no major contamination is evident in any media according to the current relevant national regulatory actions. However, findings of this study suggest that, over expanded time exposure, threat to the environment and human health may be of concern.
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The Study on the relationship of employees¡¦ perceptions of organizational politics, job involvement, and job performanceHuang, Shu-Chen 09 August 2002 (has links)
ABSTRACT
Most of the organizational politics derive either from achieving the organizational goal by organizational members, or from the purpose of maximizing self-interests. Therefore, Perceptions of Organizational Politics (POPs) might influence the perception of need satisfaction or outcome and affect job involvement and job performance. The purpose of the study is to understand the relationship among POPs, job involvement and job performance. Through empirical survey, there are several outcomes as follows:
1. Females have more political perceptions of organizational policy and practice than males do.
2. Members under 35 years old have more perceptions of supervisors¡¦ political behavior and have more perceptions of coworkers¡¦ and cliques¡¦ political behavior than members over 35 years old do.
3. Single members¡¦ POPs is higher than married members¡¦.
4. Non-managers¡¦ POPs and perceptions of coworkers¡¦ and cliques¡¦ political behavior are higher than managers.
5. The higher the managers¡¦ level, the higher the job involvement.
6. The dimensions of POPs are negatively relative to job involvement.
7. By controlling sex, marriage, age, education, service seniority, and position to examine the relationship between POPs and job performance.
7.1 Females, single, under 35 years old, college and above, seniority and managers have higher perceptions of supervisors¡¦ political behavior and lower job performance, task performance, and contextual performance.
7.2 Females, college and above, seniority, and managers have higher political perceptions of organizational policy and practice, and higher job performance.
7.3 Males, under 35 years old, college and above, less years spent on the job, non-managers have higher political perceptions of organizational policy and practice and higher task performance.
7.4 Females, seniority, and managers have higher political perceptions of organizational policy and practice and higher contextual performance.
8. As an interference variable, job involvement doesn¡¦t significantly interfere the relationship between POPs and job performance.
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Perceptions of Organizational Politics¡GAn Investigation of AntecedentsLiu, Chao-Ping 30 July 2003 (has links)
Abstract¡GThis investigation uses the model proposed by Ferris et al.,¡]1989¡^to study the relationships among the perceptions of organizational politics , employee¡¦s personal influences¡Morganizational influences¡M job/work environment influences in domestic enterprises. The sample consisted of 430 employee selected from five service organizations in Taiwan. The data were analyzed by applying statistical methods, including factor analysis, reliability, correlation and multiple linear regression. The major findings of this study are as fallow:
Perceptions of organizational politics were found have a negative relationship with age¡Mtenure¡Meducation¡Mhierarchical level¡Morganizational formalization¡Mskill variety¡Mjob autonomy¡Mjob feedback¡Mrelationship with supervisor¡Mrelationship with coworker and a positive relationship with organizational centralization. Those employee with high Machiavellians¡Mtype A personality or external locus might feel higher perceptions of organizational politics.
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The Moderators of Perceptions of Organizational Politics which Have Negatives Effects on Organization-Job Satisfaction as an ExampleChen, An-Yin 25 August 2003 (has links)
The purpose of this research is to examine the relationship between perceptions of organizational politics and job satisfaction. This research also deeply investigates the variables that moderate the perceptions of organizational politics-. These variables are understanding, control, locus of control, type A personality and the tenure working for supervisor. The objects of this research are public and privacy organizations. The sample consisted of 1643 employees selected from diverse organizations. The data was analyzed by statistical methods are descriptive statistic, t-test, ANOVA, correlation analysis, factor analysis, reliability analysis, regression analysis and hierarchical regression analysis. The major results of this study are as following:
The perceptions of organizational politics were found have a negative relationship with satisfaction. This finding also indicated that understanding and control moderated the relationship between the perceptions of organizational politics and job satisfaction. However, locus of control, type A personality and tenure working for supervisor don¡¦t have moderate effect in the relationship between perceptions of organizational politics and job satisfaction.
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Pops e famosinhos: identidade e performance de jovens na internet.Salles, Tatiana Rocha de. 30 November 2017 (has links)
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Previous issue date: 2016-02 / Esse trabalho é resultado de uma ampla pesquisa em torno de indivíduos populares
na internet, cujas atuações conseguem reunir milhares de jovens que passam a
segui-los em suas mídias sociais e fora delas. Fazendo uso das contribuições
teóricas das Ciências Sociais contemporâneas e do instrumental da metodologia
qualitativa, é feita uma análise do processo de construção das identidades e
performances de pops e de famosinhos, termo criado por esses jovens para
identificá-los nas mídias sociais, nas cidades de João Pessoa e de São Paulo. Em
um processo reflexivo, pops e famosinhos procuram se diferenciar dos seus
seguidores e de outros jovens famosos na internet através das suas ações
expressas em fotos e posts publicados no facebook. Para esses jovens, as fotos
são as grandes responsáveis pelas suas popularidades na rede e eles manipulamnas
a fim de causar a impressão necessária. Nesse sentido, os perfis pessoais de
pops e de famosinhos na internet são mídias, veículos nos quais eles fazem circular
cotidianamente os seus “estilos” e as suas atitudes “diferentes”. Para os garotos e
garotas informantes da pesquisa, o “jovem” de hoje em dia é mais “livre”, pois a
internet permite a comunicação deles com jovens de outras cidades, Estados e até
países, sem intermediários. Eles próprios regulam as suas mídias sociais e nessa
perspectiva a rede se configura como um espaço propício para a concepção de
suas identidades de jovem. Assim, ser jovem para esses agentes é zoar e curtir,
uma vez que eles encaram essa identidade de pops e de famosinhos como uma
fase das suas vidas que logo irá passar. / This work is the result of a broad research about highly popular young internet
individuals whose actions can gather thousands of fans in their social media profiles
and outside the internet as well. Through the use of theoretical contributions from
social sciences, we made an analysis of the identity construction process and
performance of pops and famosinhos, terms created by these young people to allow
their identification on the social media in the cities of João Pessoa and São Paulo.
As part of a reflexive process, pops and famosinhos aim to be different from their
own followers and from other popular teenagers on the internet through their actions
expressed by pictures of themselves and posts on facebook. To them, the pictures
are the main reason of their popularity in the web and they manipulate the
photography in order to achieve a desirable effect. In this sense, their personal
profiles are Medias, communication vehicles which they feed with information about
their style and their unusual attitude. To these boys and girls who were informants of
this research, the youth of nowadays is freer than ever, as the internet allows faceto-face
communication with people from other cities, states and even countries. They
regulate their own media by themselves and, in such perspective, the network
becomes a suitable space for the conception of their identities as young people.
Therefore, to be young for these agents is to have fun and enjoy life, once they
acknowledge that the identity of being a pop or famosinho is a phase of their lives
that will soon be over.
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Transfert des polluants organiques persistants (POP) du fourrage vers le lait chez le ruminant / Transfer of persistent organic pollutants (POP) of fodder to milk in ruminantsCostera Pastor, Adrián 11 June 2007 (has links)
Le ruminant est exposé aux POP déposés sur les prairies. Cette thèse étudie le transfert des PCDD/F, PCB et HAP du fourrage et du sol vers le lait. De l’herbe contaminée en PHE, PYR et B[a]P a été incubée dans le rumen des vaches pour déterminer la disparition in sacco des HAP, des alcanes cuticulaires et de la MS. Les 3 HAP ont disparus (83%) au bout d’1h d’incubation, tandis que les alcanes cuticulaires et la MS ont présenté une disparition plus lente. Les FT des HAP de l’herbe et du sol vers le lait a été étudié in vivo chez la chèvre. Les HAP natifs sont très faiblement transférés vers le lait quelle que soit la matrice d’apport. Le transfert des PCDD/F et PCB du foin contaminé vers le lait a été aussi étudié. Les FT des PCB ont varié de 5 à 90% et pour les PCDD/F de 1 à 40%. Le risque d’exposition de l’homme via le lait peut se présenter notamment pour les PCDD/F et PCB. Les normes actuelles sur les teneurs de HAP dans le lait ainsi que la toxicité du 1-OH-PYR devraient être précisées / Ruminant is exposed to POPs deposited on grasslands. This thesis study the transfer of PCDD/Fs, PCBs and PAHs from fodder and soil to milk. PHE, PYR and B[a]P contaminated grass was incubated in the rumen of cows in order to determine the in sacco disappearance of PAHs, cuticular n-alkanes and DM. The 3 PAHs disappeared (83%) in the 1st hour of incubation while the cuticular n-alkanes and DM disappearance was slower. The transfer of PAHs from grass and soil towards milk has been studied in vivo in goats. The transfer to milk of native PAHs is minimal whatever the matrix ingested. The transfer of PCDD/Fs and PCBs from contaminated hay to milk has been also studied. The CORs of PCBs varied from 5% to 90% and for PCDD/Fs from 1% to 40%. The risk of human exposure via milk could become meanly with PCDD/Fs an PCBs. The current safety threshold values in milk as well as toxicity of 1-OH-PYR must be reviewed
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