Animal personality can be defined as a set of physiological and behavioral characteristics that differ between individuals, but are consistent over time and across situations. The evolution of individual differences in behavior that are consistent over time and situations is still not clear. Our understanding of why animals have personality can be improved by investigating the underlying physiological mechanisms of animal behavior. Serotonin is a key monoamine that serves as a physiological modulator of animal behavior. Selective serotonin reuptake inhibitors are a group of chemicals that increase levels of serotonin in the brain. Fluoxetine is one such chemical and is used to treat depression in humans. In the field cricket (Gryllus bimaculatus), increased levels of serotonin have been linked to higher activity and boldness, which are both personality traits. In the current study, the effects of induced serotonin on activity, exploration, boldness and aggression was investigated. My results show that injecting fluoxetine causes substantial changes in behavioral traits used to describe personality in field crickets. This result is opposite to previous studies, as serotonin induced individuals were less active, less explorative, and won less fights, compared to control individuals. This could be due to serotonin existing naturally within the circulatory system of the field cricket, whereas fluoxetine is a manufactured chemical intended for human receptors, or that fluoxetine has a similar effect in modulating personality in field crickets as in humans. Since fluoxetine acts similarly in field crickets as in humans, an increased understanding of the effects of induced serotonin on different behaviors in field crickets could be beneficial for treating psychological illnesses.

Le procédé de galvanisation à chaud se compose d’un recuit continu suivi d’une immersion de la bande d’acier dans un bain de zinc afin de lui conférer une protection contre la corrosion. Au cours de l’étape de recuit de recristallisation des nouveaux aciers, dits à « haute limite élastique », les éléments d’addition, tel que l’aluminium, ségrégent et diffusent en surface où ils forment des îlots voire des films superficiels qui, mal mouillés par le zinc liquide, nuisent à la qualité du produit final. Dans ce cadre, l’étude s’est attachée d’une part à caractériser l’oxydation sélective d’alliages binaires Fe-Al et d’autre part, dans le cas modèle de l’α-alumine (0001), à déterminer les effets de la terminaison de surface sur l’énergie d’adhésion du zinc, à l’aide d’une approche combinant simulations numériques ab initio (théorie de la fonctionnelle de la densité) et expériences sous ultra-vide (réflectivité UV-visible, photoémission et désorption thermique). A l’issu de recuits calqués sur les conditions industrielles les alliages binaires Fe-Al (1,5 et 8% pds.) présentent en surface une couche couvrante d’γ-alumine de plusieurs nanomètres d’épaisseur. Une entrée du flux de gaz focalisée sur l’échantillon aboutit à une croissance vermiculaire des grains d’alumine alors qu’un flux de gaz homogène engendre une croissance plus structurée qui montre que l’approche modèle Zn/α-alumine (0001) est pertinente.Les simulations numériques faites aux premiers stades du dépôt, ont montré que, le zinc interagit faiblement avec la surface stœchiométrique (1x1), ce qui confirme l’expérience. Expérience et calcul convergent sur la valeur de ≈ 0,5 eV de l’énergie d’adsorption. Par contre, un excès de charge de surface peut considérablement renforcer l’adsorption. Deux mécanismes ont été identifiés et décrits en terme de stabilité thermodynamique, en fonction des conditions environnementales (pression, température) : (i) une sous-stœchiométrie surfacique en Al, telle que présente sur la terminaison polaire, (ii) un excès de groupements hydroxyles de surfaces, issus de la dissociation de l’eau, opérationnel aussi bien sur la terminaison polaire que non-polaire de l’alumine. En parallèle avec l’expérience, la simulation montre que le zinc est capable d’interagir fortement avec la surface en en déplaçant l’hydrogène des groupements hydroxyles de surface. L’énergie d’adsorption du zinc ainsi adsorbé, évaluée à 7 eV par le calcul, est du même ordre que la valeur expérimentale de 3,5 eV. L’étude étendue à plusieurs métaux de transition a permis d’identifier le titane comme élément montrant l’interaction la plus forte avec l’alumine et qu’un enrichissement en titane de la surface d’alumine peut fortement améliorer l’adhésion du zinc. / The process of continuous hot galvanization consists in annealing and then diving a steel strip in a zinc bath to confer it a protection against corrosion. During the recrystallization annealing step of the so call “high elastic limit’ steels, the additional elements, such as aluminum, segregate and diffuse towards the surface and form oxide islands or superficial film which degrade the zinc adhesion and harm the final quality. This study attempted, on one hand to characterize the selective oxidation of binary alloys and, on the other hand, to improve adhesion at the zinc/α-Al2O3 (0001) interface taken as a test bed. The originality of the research program is to be based on both numerical ab initio simulation (density functional theory) and experiments (UV-vis reflectivity, photoemission, thermal desorption) to determine the parameters of greater relevance.After annealing based on industrial conditions, binary alloys (1.5%- 8% wt.) are totally covered by γ-alumina layer some nanometers in thickness. Gas flow focused on the sample leads to a ‘worm’ like growth of the alumina grains while an homogeneous flow gives rise to a well- structured growth which shows the relevance of the study of Zn/α-alumina (0001).The numerical simulations of the early stage of deposition show that, zinc interacts weakly on a stoichiometric surface (1x1) what is in agreement with experiments. Experiment and theory converge on 0.5 eV for adhesion energy. On the other hand, an excess of surface charge can considerably reinforce the adsorption. Two mechanisms were identified and described in terms of thermodynamics stability according to the environmental conditions (pressure, temperature): (i) electron deficiency present at polar termination, such as oxygen rich (ii) an excess of surface hydroxyls groups issued from water dissociation. Interestingly, this effect is operational on both polar and non-polar terminations. In parallel with experiments, calculation show zinc is able to spill over the hydroxyls groups and interact strongly with the surface. Adhesion energy is 7 eV which is in a good agreement with the 3.5 eV of experimental value. Extended over the 3d transition metals series, the calculations identify titanium as the element exposing the strongest interaction with alumina. By focusing on the adhesive characteristics at the Zn/alumina interfaces, calculations show that titanium enrichment can indeed improve considerably the adhesion.

The focus of this project was to investigate the use of interdigitated electrodes (IDEs) as impedimetric ion-selective chemical sensors for the determination of several important analytes found within a freshwater aquarium. The overall aim of this research was to work towards a prototype sensing device that could eventually be developed into a commercial product for sale to aquarium owners. Polyvinyl chloride and sol-gels containing commercially-available ionophores for four aquarium-significant ions (NH4+, NO2-, NO3- and pH) were prepared and investigated for use within polymeric ion-selective membranes. Three separate IDE transducers were produced using either photolithography or screen-printing microfabrication techniques. A sinusoidal voltage was applied to the IDEs and an LCR meter was used to measure changes in the conductance and capacitance of the ion-selective membrane layer deposited over the electrode digits. Each ionophore, when tested within potentiometric ion-selective electrodes (ISEs), was found to be suitable for further investigation within IDE devices. Sol-gels were investigated as a potential membrane material for a coated wire electrode; however, poor response characteristics were observed. An IDE sensor fabricated in-house using lift-off photolithography and spin-coated with a polymeric membrane was found to produce non-selective responses caused by changes in the conductivity of the test solution. IDE devices with reduced geometric parameters were purchased and coated with a selective polymeric membrane. When the membrane was spin-coated, non-selective responses were observed; therefore, drop-coating of the membrane material was investigated. This initially resulted in an unacceptably long response time; however, this effect was reduced by decreasing the membrane solution viscosity prior to drop-coating. A fully-screen printed carbon IDE device was fabricated by incorporating the ionophore into a support matrix based on a commercial dielectric paste. Matrix interferences to the sensor response were reduced by printing ‘build-up’ layers over the sensing area prior to the ion-selective membrane. Two novel routes for monitoring the water quality of an aquarium, using IDE sensors fabricated by either photolithography or screen-printing, have been demonstrated. Due to the commercial aspect of this project, it is important to consider the final cost of producing these sensors. Both of the techniques used to produce ion-selective sensors require further experimentation to optimise the sensor response, prior to integration within a multi-analyte sensing prototype.

This Diploma thesis deals with a Software as a Service (SaaS) architecture model in a private business. The goal is to identify factors which influence the decision making process of potential SaaS acquisition and whether the factors are dependent on characteristic of the business. The thesis may serve companies as a guideline to follow customer's SaaS solution demand. In order to achieve the goal, economical, marketing and IT aspects of SaaS are discussed first in the theoretical part. According to these aspects selective factors and business characteristics are determined. Practical part presents a survey which was performed among Czech companies in order to obtain a relevant data enabling to evaluate dependencies between selective factors and business characteristics. After the analysis of the data a result of the survey and identified dependencies are introduced. Furthermore, the author's suggestions to the SaaS suppliers are presented in the conclusion.

The subject of the thesis is the fiscal and allocation function of selective excise taxes with focus on the Czech Republic. Due to the fact that the Czech Republic is among countries that apply "traditional excise duties" in their taxation mix, the subjects of which are assumed to have low elasticity of demand, the question is whether these taxes may perform the allocation function. Analysis of the fiscal function is based on the comparison of percentage of excise duties in overall tax revenues of public budgets, and on the development of this portion in time in the EU countries. Stability of revenues resulting from these taxes is verified by variability measures. On the grounds of the performed analysis it can be stated that excise duties in the Czech Republic represent stable revenue of the national budget. Allocation function of these taxes is analysed by graphic depiction and description of the trend of consumption of selected products and of the trend of prices in the period between 1995 and 2010. The trend of prices of selected products is estimated as the difference between interannual changes in the consumer price index for selected product groups and the overall consumer price index. This analysis did not prove unequivocally that the selective excise taxes imposed on the analysed commodities would be able to perform the allocation function.

Orientador: Luiz Carlos Kretly / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-24T13:36:57Z (GMT). No. of bitstreams: 1 Silva_MauricioWeberBenjoda_D.pdf: 10953654 bytes, checksum: 6b4d1b6000f187a807b5cec8ba653713 (MD5) Previous issue date: 2014 / Resumo: Neste trabalho, as diferentes propriedades de superfícies seletivas em frequência, FSS - Frequency Selective Surfaces, são analisadas. As FSS são estruturas planares com células periódicas e podem ser classificadas como uma classe de metamateriais. Para tanto, o mecanismo de trabalho dessas estruturas foi extensivamente estudado, e um método próprio, baseado no modelo de circuito equivalente em conjunto com simulações de onda completa foi proposto. A ferramenta desenvolvida é útil para uma análise preliminar rápida de FSS, a qual foi utilizada para criar uma base de dados de elementos conhecidos na literatura. Diferente dos modelos de análise clássicos, a modelagem analítica proposta, que é uma das principais contribuições do trabalho, usa um simples algoritmo para aproximar a resposta de superfícies seletivas em frequência com geometrias arbitrárias, para incidências normal e oblíqua e para substratos com quaisquer espessuras. Nesse sentido, após a simulação eletromagnética da estrutura, é possível computar a resposta de uma FSS com diferentes parâmetros sem o consumo de tempo das simulações de onda completa. O modelo usa as características peculiares de superfícies de alta impedância, HIS - High Impedance Surface, que dentro de determina faixa comporta-se como condutor magnético perfeito, PMC - Perfect Magnetic Conductor, enquanto no restante da banda tem comportamento de um condutor elétrico perfeito, PEC - Perfect Electric Conductor, para sintetizar absorvedores finos e planares de micro-ondas. As estruturas, compostas de superfície seletiva em frequência resistivas sobre um substrato dielétrico aterrado, são projetadas visando aplicação em diferentes faixas de frequência de absorção e diferentes larguras de banda. Na faixa de 5,5 GHz, objetivou-se satisfazer as especificações dos sistemas WIMAX, WLAN, com os padrões IEEE 802.11a, bem como sistemas de radar, enquanto sinais de outras faixas podem trafegar com atenuação mínima ou nula. Para a faixa mais elevada, projetou-se uma estrutura que oferece absorção sobre a faixa de frequências de 10 GHz a 18 GHz, que pode ser empregada visando aplicações na banda-X e banda-Ku. O método de modelagem para a FSS e para os absorvedores propostos foi validado fisicamente através de montagens experimentais e instrumentação, especialmente desenvolvidas para estas estruturas. Os protótipos dos absorvedores fabricados são extremamente finos e foram medidos por meio de setups de medida em campo aberto e em câmara anecóica. As estruturas projetadas mostraram excelente desempenho para as faixas medidas, mantendo refletividade tipicamente abaixo de -10 dB ao longo de toda a banda. A metodologia desenvolvida nesta pesquisa pode ser ampliada para diferentes faixas de frequências, larguras de banda e aplicações / Abstract: In this work, the different properties of frequency selective surfaces - FSS are analyzed. Frequency selective surfaces are planar structures with periodic cells and can be classified as a kind of metamaterials. To this end, the working mechanism of these structures has been extensively studied, and a proper method based on the equivalent circuit model in conjunction with full-wave simulations was proposed. The developed tool is useful for a fast preliminary analysis of FSS, which was used to create a database of known elements presented in the literature. Unlike of classical analysis model, the proposed analytical modeling, which is one of the main thesis contributions, uses a simple algorithm for approximate the response of frequency selective surfaces with arbitrary shape, for normal and oblique incidence and for substrates with all thicknesses. In this sense, after the electromagnetic simulation of the structure, it is possible to compute the response of an FSS with different parameters without the time consuming full-wave simulations. The model uses the unique characteristics of High-Impedance Surfaces - HIS, which for certain frequency range, behaves as Perfect Magnetic Conductor - PMC, while outside this band behaves as a Perfect Electric Conductor - PEC, for synthesizing thin planar microwave absorbers. The structures, comprising resistive frequency selective surfaces over a grounded dielectric substrate, are designed aiming different absorption frequency bands and different bandwidths. In the 5.5 GHz frequency range, the aim was to satisfy the specifications of WiMAX, WLAN systems, in view of the IEEE 802.11a standards, as well as radar systems, while signals from other bands can travel across with zero or minimal attenuation. To the highest range, the designed structure provides absorption over 10 GHz to 18 GHz frequency range, and can be applied to the X- and Ku- band. The modeling method for the FSS and the proposed absorbers was physically validated through experimental setups and instrumentation, especially developed for these structures. The prototype of the fabricated absorbers are extremely thin and were characterized by using free space and anechoic chamber measurement setups. The designed structures showed excellent performance for measurements ranges, with reflectivity typically below -10 dB over the entire band. The methodology developed in this research can be extended to different frequency bands, bandwidth and applications / Doutorado / Eletrônica, Microeletrônica e Optoeletrônica / Doutor em Engenharia Elétrica

INTRODUÇÃO: A misofonia é caracterizada pela aversão a sons bem seletivos, que provocam uma forte reação emocional. Foi proposto que a misofonia, assim como o zumbido, esteja associada à hiperconectividade entre os sistemas auditivo e límbico. Indivíduos com zumbido de incômodo significativo podem apresentar comprometimento da atenção seletiva, o que ainda não foi demonstrado no caso da misofonia. OBJETIVO: caracterizar uma amostra de indivíduos com misofonia e compará-la com dois grupos controle, um com zumbido (sem misofonia) e outro assintomático (sem zumbido e sem misofonia). METODOLOGIA: Foram avaliados 40 sujeitos normo-ouvintes, sendo 10 com misofonia (grupo misofonia - GM), 10 com zumbido (sem misofonia) (grupo controle zumbido - GCZ) e 20 sem zumbido e sem misofonia (grupo controle assintomático - GCA). Foi realizada anamnese geral em todos os grupos e anamnese específica apenas para o GM. Nos três grupos, foi aplicado o Teste de Identificação de Sentenças Dicóticas em três situações. Na primeira, foi realizado o exame padrão. Em seguida, foi aplicado incluindo mensagem competitiva, uma com som de mastigação (exame mastigação), e outra com white noise (exame white noise). RESULTADOS: A amostra do GM apontou que os primeiros sintomas da misofonia foram percebidos ainda na infância ou adolescência (média 11,5 anos). O grau de incômodo variou de 6 a 10 na escala visual analógica e, dentre os 10 participantes do GM, nove (90%) responderam que a misofonia atrapalha, sempre ou às vezes, a vida social e profissional. No teste de Identificação de Sentenças Dicóticas, foi observado que no exame mastigação, as médias da porcentagem de acertos diferem entre os grupos GM e GCA (valor-p = 0,027) e entre os grupos GM e GCZ (valor-p = 0,002), sendo menor em ambos os casos no GM. Para os exames padrão e white noise, não há diferença entre as médias da porcentagem de acertos nos três grupos (valores-p >= 0,452). CONCLUSÃO: os participantes do GM apresentaram menor porcentagem de acertos no Teste de Identificação de Sentenças Dicóticas na situação de apresentação de um ruído distraidor (exame mastigação) em relação ao mesmo teste aplicado em situação padrão ou white noise, sugerindo que indivíduos com misofonia podem apresentar alteração da atenção seletiva quando expostos a sons que desencadeiam esta condição / INTRODUCTION: Misophonia is characterized by the aversion to very selective sounds, which evoke a strong emotional reaction. It has been proposed that misophonia, as well as tinnitus, is associated with hyperconnectivity between the auditory and limbic systems. Individuals with bothersome tinnitus may have selective attention impairment, but it has not been demonstrated in case of misophonia yet. OBJECTIVE: to characterize a sample of misophonic subjects and compare it to two control groups, one with tinnitus individuals (without misophonia) and the other one with asymptomatic individuals (without misophonia and without tinnitus), regarding self-perception of the condition and selective attention. METHODOLOGY: we had evaluated 40 normal hearing participants: 10 with misophonia (GM), 10 with tinnitus (without misophonia) (GCZ) and 20 without tinnitus and without misophonia (GCA). General questionnare was applied in all of three groups and specific misophonia questionnaire was applied only in GM. In order to evaluate the selective attention, it was applied the Dichotic Sentence Identification (DSI) Test in three situations: In the first one, it was applied the original test. Then, the test was applied in two other situations including two competitive sounds, one with chewing sound (chewing test), and the other one with white noise sound (white noise test). RESULTS: The GM sample indicated that the onset of misophonia occurred in childhood or adolescence (mean 11.5 years). According to the visual analog scale, the discomfort with misophonia ranged from 5 to 10, and nine (90%) participants answered that misophonia always or sometimes limits their social and professional interactions. In the chewing test, it was observed that the average of correct responses differed between GM and GCA groups (pvalue = 0.027) and between GM and GCZ groups (p-value = 0.002), in both cases it was lower in GM. In the original and white noise tests, no difference was observed between the averages of correct responses in the three groups (p-values >= 0.452). CONCLUSION: The GM participants had a lower percentage of correct responses in the chewing test, suggesting that individuals with misophonia may have selective attention impairment when they are exposed to sounds that trigger the condition

Este ensaio clinico randomizado controlado avaliou a eficácia do uso da proteção pulpar indireta com cimento de hidróxido de cálcio (HC) ou sistema adesivo universal (AU) num período de seis meses de acompanhamento em lesões profundas de cáries em dentes permanentes após a remoção seletiva de tecido cariado (RSTC). Métodos: Participaram do estudo 48 pacientes, (mediana de idade de 27 anos [distribuição 7-54 anos]), com 41 molares e 15 premolares com lesões profundas de cárie (envolvimento radiográfico ≥50% de profundidade de dentina), sensibilidade pulpar positiva ao teste frio (gás refrigerado, -50°C, Maquira, PR, Brasil), ausência de dor espontânea, sensibilidade negativa aos testes de percussão, ausência de perda cuspídea e ausência de imagem radiográfica sugestiva de lesão periapical (radiografia periapical - VistaScan®). Após a remoção seletiva de tecido cariado para dentina amolecida, o grupo teste do ensaio recebeu um sistema adesivo universal (Universal single bond, 3M Espe, Brasil), enquanto o grupo controle recebeu a proteção pulpar indireta com cimento de hidróxido de cálcio (Dycal, Dentisply, Rj, Brasil). Todos os dentes foram imediatamente restaurados seguindo o condicionamento ácido seletivo em esmalte, aplicação de um sistema adesivo universal (AU) e resina composta nanoparticulada (Filtek Z350, 3M Espe, SP, Brasil). O desfecho de sucesso para vitalidade pulpar avaliou após seis meses: sensibilidade pulpar positiva ao teste frio, ausência de imagem sugestiva de lesão periapical (radiografia periapical - VistaScan®), ausência de dor espontânea e sensibilidade negativa à percussão vertical. Os dados foram submetidos à análise de sobrevida de Kaplan-Meier e teste Log Rank, e as variáveis idade (mediana), gênero, escolaridade, IPV, ISG, CPO-D, CPO-S, número de faces da restauração, tipo do dente, proteção pulpar indireta, profundidade da lesão (≥50% da profundidade da dentina ou ≥75% da profundidade da dentina) e presença de antagonista, quanto as suas distribuições nos dois grupos de tratamento pelos testes qui-quadrado e de Mann-Whitney. Resultados: As taxas de sucesso foram de 93.3% para o grupo controle (HC) e de 95.8% para o grupo teste (AU) (P=0.976). Dois casos de insucesso foram registrados, sendo necrose pulpar (grupo controle) e pulpite (grupo teste). As variáveis analisadas no início do estudo mostram uma amostra igualmente distribuída entre os grupos de tratamento. Nenhuma das variáveis foi relacionada ao insucesso. Os resultados sugerem que não há diferença entre o uso ou não de HC na proteção pulpar indireta após remoção 7 seletiva de tecido cariado em seis meses de acompanhamento, apresentando uma taxa de sucesso alta independente do tratamento. / This randomized controlled clinical trial evaluated the effectiveness of using indirect pulp protection with calcium hydroxide liner (CH) or universal adhesive (UA) over a period of 6 months in deep caries lesions on permanent teeth after selective removal to soft dentin (SCRSD). Methods: The sample consisted of 41 molars and 15 premolars (with radiographic involvement of the inner half of the dentin), from 48 patients, (median age 27 [distribution 7-54 years]), with positive response to cold test (refrigerated gas, -50 °C, Maquira, PR, Brazil), absence of spontaneous pain, negative sensitivity to percussion tests, absence of cuspid loss and absence of radiographic imaging suggestive of periapical lesion (periapical radiography). After the selective removal to soft dentin, the test group received a universal adhesive system (Universal Single Bond, 3M Espe, Brazil) whereas the control group received indirect pulp protection with calcium hydroxide liner (Dycal, Dentisply, Rj, Brazil). All teeth were restored following selective acid condition for enamel, adhesive system (UA) and nanoparticulate composite resin (Filtek Z350, 3M Espe, SP, Brazil). The successful outcome for pulp vitality assessed after six months: positive pulpal sensitivity to the cold test, absence of image suggestive of periapical lesion (periapical radiography - VistaScan®), absence of spontaneous pain and negative response to vertical percussion test. The results were submitted to the Kaplan-Meier survival analysis and the Log Rank test and the variables: age of subjects, gender, schooling, plaque index, gingival bleeding index, DMF-T, DMF-S, number of surfaces involved in the filling, type of the tooth, indirect pulp material, size of lesion (≥50% of dentine or ≥75% of dentine) and antagonist, analyzed for their distribution in the two treatment groups by the tests chi-square and Mann-Whitney. Results: The success rates were 93.3% for the control group (CH) and 95.8% for the test group (UA) (P=0,976). Only two cases of failure were recorded, one pulp necrosis (control group) and pulpitis (test group). The variables analyzed at the beginning of the study show a similarly distributed sample between treatment groups. The results suggest that there is no difference between the use of CH or UA in indirect pulp protection after SCRSD followed by composite restoration at six months of follow-up, showing a high rate of success for both treatments.

abstract: The “filter bubble” has been a heated discussion topic since several years ago. In addition to possible algorithmic contribution to this phenomenon, people’s selective exposure tendency may be another primary cause of the “filter bubble” on social media. Prior research indicates that, under the influence of selective exposure tendency, people tend to perceive pro-attitudinal news as more credible than counter-attitudinal news, with strong partisans more likely to be affected. The proposed thesis seeks to examine whether the perceived credibility of a news source and story on social media is influenced by selective exposure and strength of partisanship. Through an experimental study via Amazon’s Mechanical Turk, 468 participants chose or were assigned to read an ostensible news story from a social media feed with the news source and ideological slant varied between participants. The results showed that people reported higher perceived source and story credibility when the source and stories were pro-attitudinal (consistent with their political ideology) as opposed to counter-attitudinal, regardless of participants’ age, race, perceived credibility of news from social media, in general, and strength of partisanship. However, contrary to the hypotheses, selective exposure behavior (i.e., choosing a preferred news source before reading a news story) did not affect credibility perceptions when participants read counter-attitudinal news from a pro-attitudinal source. Last, strength of partisanship did not moderate the influence of selective exposure on credibility perceptions. In sum, this study suggests that although selective exposure tendency may affect people’s credibility perceptions and contribute to “filter bubbles,” the impact of selective exposure behavior may be overestimated in terms of perceived source and story credibility of news on social media. / Dissertation/Thesis / Masters Thesis Public Administration 2020

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