Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2017-04-24T11:45:18Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação Tassiana Ramires.pdf: 1728606 bytes, checksum: a63d0903f11cb3f858c5a7fd4e32ad97 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-05-04T18:58:35Z (GMT) No. of bitstreams: 2 Dissertação Tassiana Ramires.pdf: 1728606 bytes, checksum: a63d0903f11cb3f858c5a7fd4e32ad97 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-05-04T18:58:35Z (GMT). No. of bitstreams: 2 Dissertação Tassiana Ramires.pdf: 1728606 bytes, checksum: a63d0903f11cb3f858c5a7fd4e32ad97 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-02-20 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Campylobacter termofílicos são, atualmente, as principais bactérias causadoras de doenças gastrointestinais em todo o mundo. Esse grupo é assim denominado devido a sua temperatura ótima de multiplicação oscilar entre 42 °C e 43 °C, sendo Campylobacter jejuni, C. coli, C. lari e C. upsaliensis, as principais espécies envolvidas nos casos de campilobacteriose em humanos. Dentre essas espécies, a mais relacionada à essa doença é C. jejuni, seguida por C. coli. O principal reservatório desses micro-organismos são as aves, principalmente os frangos, possivelmente pela temperatura corporal desses animais ser similar à temperatura ótima para Campylobacter termofílicos. Com isso, o objetivo desse estudo foi avaliar a ocorrência, a diversidade genética, o perfil de resistência a antimicrobianos e a presença de genes associados à virulência em isolados de Campylobacter termofílicos provenientes de frangos de corte e na cama de aviário em granjas aviárias da região sul do Rio Grande do Sul, Brasil. Um total de 48 amostras foram coletadas em três diferentes granjas (A, B e C), incluindo uma amostra de swab de arrasto da cama do aviário e 15 pools de amostras de swab de cloaca em cada granja. Das três granjas amostradas, apenas a granja C apresentou contaminação por Campylobacter termofílicos, sendo todos os isolados identificados por técnicas fenotípicas e moleculares como C. jejuni. Dessas 16 amostras positivas, obtiveram-se 28 isolados, sendo 16 pelo isolamento em ágar Preston e 12 do ágar mCCD. A diversidade genética entre os isolados foi avaliada por PFGE, verificando-se que todos os isolados apresentaram um único padrão de macrorestrição, sugerindo clonalidade entre os isolados e a presença de apenas uma fonte de infecção por Campylobacter nessa granja. O perfil de resistência a antimicrobianos foi avaliado pelo teste de disco difusão em ágar, utilizando-se oito antimicrobianos distintos, de três classes diferentes: tetraciclina, quinolonas e macrolídeos. Os isolados apresentaram perfil similar de resistência a antimicrobianos, sendo resistentes às quinolonas e tetraciclinas e sensíveis aos macrolídeos. Devido a relação clonal e ao perfil de resistência similar, um isolado representativo foi selecionado para detecção dos genes de virulência. A técnica de PCR foi utilizada para detectar a presença dos genes ciaB, cadF, cdtA, cdtB e cdtC, sendo o isolado selecionado positivo todos os genes pesquisados. Dessa forma, a presença de C. jejuni resistente a antimicrobianos e com potencial de virulência em frangos de corte prontos para o abate e na cama de aviário durante o período de produção é um risco à saúde pública, pois esses micro-organismos podem ser introduzidos no ambiente do abatedouro e contaminar as carcaças durante o abate. / Thermophilic Campylobacter are currently the leading bacteria causing of gastrointestinal diseases worldwide. This group is so named because its optimal multiplication temperature oscillates between 42 °C and 43 °C, being Campylobacter jejuni, C. coli, C. lari and C. upsaliensis, the main species involved in cases of human campylobacteriosis. Among these species, the most related to this disease is C. jejuni, followed by C. coli. The main reservoir of these microorganisms are birds, especially chickens, possibly because the body temperature of these animals coincides with the optimal temperature for thermophilic Campylobacter. Therefore, the aim of this study was to verify the occurrence, genetic relationship, antimicrobial susceptibility, and the presence of virulence genes in thermophilic Campylobacter from broilers and broiler bedding from the southern region of Rio Grande do Sul, Brazil. A total of 48 samples were collected in three different farms (A, B and C), which comprising one sample of drag swab and 15 pools of cloacal swabs in each farm. From the three farms sampled, only the farm C showed thermophilic Campylobacter contamination. All isolates were identified by phenotypic and molecular techniques such as C. jejuni. Of these 16 positive samples, 28 isolates were obtained, 16 being isolated by Preston agar and 12 by mCCD agar. The genetic diversity among the isolates was evaluated by PFGE, and it was observed that all the isolates belonged to the same macrorestriction pattern, suggesting clonality among the isolates and the presence of only one source of Campylobacter infection in this farm. The antimicrobial resistance profile was evaluated by the agar disc diffusion test using eight distinct antimicrobial agents from three different classes: tetracyclines, quinolones and macrolides. The isolates presented a similar antimicrobial resistance profile, being resistant to quinolones and tetracyclines and susceptible to macrolides. As the isolates shared the same PFGE pattern and similar resistance profile, a representative isolate was chosed for investigation of virulence genes. A PCR assay was carried out aiming to identify the presence of ciaB, cadF, cdtA, cdtB and cdtC virulence genes and all the genes evaluated were found. Thus, the presence of C. jejuni resistant to antimicrobial agents and harboring virulence genes in broilers and broiler farm during the broiler production period may represents a potential risk to public health, because these microorganisms can be introduced into the abattoir environment and may contaminate the carcasses during slaughter.

Cooperative wireless communication has received significant attention during recent years due to several reasons. First, since the received power decreases rapidly with distance, the idea of multi-hopping is becoming of particular importance. In multi-hopped communication, the source exploits some intermediate nodes as relays. Then the source sends its message via those relays to the destination. Second, relays can emulate some kind of distributed transmit antennas to form spatial diversity and combat multi-path fading effect of the wireless channel. Parallel Relay Channel is an information theoretical model for a communication system whereby a sender aims to communicate to a receiver with the help of relay nodes. It represents the simplest model for a multi–hop wireless network and a full understanding of the limits of communication over such a channel can potentially shed light on the design of more efficient wireless networks. However, the capacity of the relay channel has been established only for few special cases and little progress has been made toward solving the general case since the early 1980s. In this dissertation, motivated by practical constraints, we study the information theoretical limits of the half-duplex Gaussian Parallel Relay channel , as well as, the transmission strategies for the parallel relay channel with bandwidth mismatch between the first and the second hops. Chapter 2 investigates the problem of communication for a network composed of two half-duplex parallel relays with additive white Gaussian noise (AWGN). There is no direct link between the source and the destination. However, the relays can communicate with each other through the channel between them. Two protocols, i.e., \emph{Simultaneous} and \emph{Successive} relaying, associated with two possible relay scheduling are proposed. The simultaneous relaying protocol is based on \emph{Broadcast-multiaccess with Common Message (BCM)} scheme. For the successive relaying protocol: (i) a \emph{Non-Cooperative} scheme based on the \emph{Dirty Paper Coding (DPC)}, and (ii) a \emph{Cooperative} scheme based on the \emph{Block Markov Encoding (BME)} are considered. The composite scheme of employing BME in \emph{at most} one relay and DPC in \emph{at least} another one is shown to achieve at least the same rate when compared to the \emph{Cooperative} and \emph{Non-Cooperative} schemes. A \emph{``Simultaneous-Successive Relaying based on Dirty paper coding scheme" (SSRD)} is also proposed. The optimum scheduling of the relays and hence the capacity of the half-duplex Gaussian parallel relay channel in the low and high signal-to-noise ratio (SNR) scenarios is derived. In the low SNR scenario, it is revealed that under certain conditions for the channel coefficients, the ratio of the achievable rate of the simultaneous relaying based on BCM to the cut-set bound tends to be 1. On the other hand, as SNR goes to infinity, it is proved that successive relaying, based on the DPC, asymptotically achieves the capacity of the network. Schein and Gallager introduced the Gaussian parallel relay channel in 2000. They proposed the Amplify-and-Forward (AF) and the Decode-and-Forward (DF) strategies for this channel. For a long time, the best known achievable rate for this channel was based on the AF and DF with time sharing (AF-DF). Recently, a Rematch-and-Forward (RF) scheme for the scenario in which different amounts of bandwidth can be assigned to the first and second hops were proposed. In chapter 3, we propose a \emph{Combined Amplify-and-Decode Forward (CADF)} scheme for the Gaussian parallel relay channel. We prove that the CADF scheme always gives a better achievable rate compared to the RF scheme, when there is a bandwidth mismatch between the first hop and the second hop. Furthermore, for the equal bandwidth case (Schein's setup), we show that the time sharing between the CADF and the DF schemes (CADF-DF) leads to a better achievable rate compared to the time sharing between the RF and the DF schemes (RF-DF) as well as the AF-DF.

Cooperative wireless communication has received significant attention during recent years due to several reasons. First, since the received power decreases rapidly with distance, the idea of multi-hopping is becoming of particular importance. In multi-hopped communication, the source exploits some intermediate nodes as relays. Then the source sends its message via those relays to the destination. Second, relays can emulate some kind of distributed transmit antennas to form spatial diversity and combat multi-path fading effect of the wireless channel. Parallel Relay Channel is an information theoretical model for a communication system whereby a sender aims to communicate to a receiver with the help of relay nodes. It represents the simplest model for a multi–hop wireless network and a full understanding of the limits of communication over such a channel can potentially shed light on the design of more efficient wireless networks. However, the capacity of the relay channel has been established only for few special cases and little progress has been made toward solving the general case since the early 1980s. In this dissertation, motivated by practical constraints, we study the information theoretical limits of the half-duplex Gaussian Parallel Relay channel , as well as, the transmission strategies for the parallel relay channel with bandwidth mismatch between the first and the second hops. Chapter 2 investigates the problem of communication for a network composed of two half-duplex parallel relays with additive white Gaussian noise (AWGN). There is no direct link between the source and the destination. However, the relays can communicate with each other through the channel between them. Two protocols, i.e., \emph{Simultaneous} and \emph{Successive} relaying, associated with two possible relay scheduling are proposed. The simultaneous relaying protocol is based on \emph{Broadcast-multiaccess with Common Message (BCM)} scheme. For the successive relaying protocol: (i) a \emph{Non-Cooperative} scheme based on the \emph{Dirty Paper Coding (DPC)}, and (ii) a \emph{Cooperative} scheme based on the \emph{Block Markov Encoding (BME)} are considered. The composite scheme of employing BME in \emph{at most} one relay and DPC in \emph{at least} another one is shown to achieve at least the same rate when compared to the \emph{Cooperative} and \emph{Non-Cooperative} schemes. A \emph{``Simultaneous-Successive Relaying based on Dirty paper coding scheme" (SSRD)} is also proposed. The optimum scheduling of the relays and hence the capacity of the half-duplex Gaussian parallel relay channel in the low and high signal-to-noise ratio (SNR) scenarios is derived. In the low SNR scenario, it is revealed that under certain conditions for the channel coefficients, the ratio of the achievable rate of the simultaneous relaying based on BCM to the cut-set bound tends to be 1. On the other hand, as SNR goes to infinity, it is proved that successive relaying, based on the DPC, asymptotically achieves the capacity of the network. Schein and Gallager introduced the Gaussian parallel relay channel in 2000. They proposed the Amplify-and-Forward (AF) and the Decode-and-Forward (DF) strategies for this channel. For a long time, the best known achievable rate for this channel was based on the AF and DF with time sharing (AF-DF). Recently, a Rematch-and-Forward (RF) scheme for the scenario in which different amounts of bandwidth can be assigned to the first and second hops were proposed. In chapter 3, we propose a \emph{Combined Amplify-and-Decode Forward (CADF)} scheme for the Gaussian parallel relay channel. We prove that the CADF scheme always gives a better achievable rate compared to the RF scheme, when there is a bandwidth mismatch between the first hop and the second hop. Furthermore, for the equal bandwidth case (Schein's setup), we show that the time sharing between the CADF and the DF schemes (CADF-DF) leads to a better achievable rate compared to the time sharing between the RF and the DF schemes (RF-DF) as well as the AF-DF.