2,198 research outputs found
Long-Range Connections in Transportation Networks
Since its recent introduction, the small-world effect has been identified in
several important real-world systems. Frequently, it is a consequence of the
existence of a few long-range connections, which dominate the original regular
structure of the systems and implies each node to become accessible from other
nodes after a small number of steps, typically of order .
However, this effect has been observed in pure-topological networks, where the
nodes have no spatial coordinates. In this paper, we present an alalogue of
small-world effect observed in real-world transportation networks, where the
nodes are embeded in a hree-dimensional space. Using the multidimensional
scaling method, we demonstrate how the addition of a few long-range connections
can suubstantially reduce the travel time in transportation systems. Also, we
investigated the importance of long-range connections when the systems are
under an attack process. Our findings are illustrated for two real-world
systems, namely the London urban network (streets and underground) and the US
highways network enhanced by some of the main US airlines routes
"Brachyspira hampsonii" associated diarrhea in pigs: virulence assessment and host-pathogen interactions
This thesis aimed to verify the causal association between "B. hampsonii" and the re-emergence of mucohaemorrhagic diarrhea in North American swine farms, to investigate the role of the intestinal microbiome as a predisposing factor for infection, to develop a porcine colon in vitro culture model and to apply this model in investigating early host-pathogen interactions.
Two infection trials were conducted to determine the pathogenicity of "B. hampsonii" clade II and clade I. Weanling pigs were divided into control (n=6) and inoculated (n=12) groups. In each trial, pigs were inoculated with "B. hampsonii" clade II (tissue homogenate or pure culture) or clade I (pure culture) or sterile culture media. Animals were monitored for clinical signs of diarrhea and upon observation of bloody diarrhea they were necropsied for characterization of lesions. Fecal shedding of "B. hampsonii" was monitored throughout the trials using culture and quantitative real-time PCR. Pre and post-diarrhea fecal samples from the clade II infection trial were used to study the microbiome response to "B. hampsonii" infection and to determine if pre-inoculation microbiome composition differed between pigs that did or did not develop clinical disease. For in vitro model development, numerous factors associated with explant survivability in culture were investigated to develop a protocol for culture of porcine colon explants. The optimized model was used to study the first 12 hours of "B. hampsonii" clade II interaction with the host using a combination of histopathology and gene expression analysis.
Pigs inoculated with "B. hampsonii" clade I (9/11) and clade II (9/12 and 8/12 in the tissue homogenate and pure culture experiments, respectively) developed mucohaemorrhagic diarrhea and colitis within 14 days of inoculation. In all trials, mucohaemorrhagic diarrhea was significantly more common in inoculated pigs than controls. No significant differences in richness, diversity or taxonomic composition distinguished the pre-inoculation microbiomes of affected or unaffected clade II inoculated pigs. After the development of diarrhea, the fecal microbiome of diarrheic pigs was more dense and had a had a lower Bacteroidetes:Firmicutes ratio when compared to inoculated but unaffected or control pigs. Cultured porcine colon explants displayed differentiated epithelium and crypts after 5 days in culture, while expressing GAPDH at a constant rate. For explants to thrive in vitro our results suggested the use of distal spiral colon, processed immediately after euthanasia, and cultured in an oxygen-rich gas mix with air-liquid culture interface in media containing antibiotics and antifungals. Explants exposed to "B. hampsonii" for 12 hours had a greater number of necrotic cells and thicker catarrhal exudate than control explants. Interaction of spirochaetes with the epithelium, necrotic cells and crypts was visible under optical microscopy, and a trend of increased expression of IFN-γ and e-cadherin in inoculated explants relative to control explants was observed.
Taken together, results of this thesis demonstrate that "B. hampsonii" causes mucohaemorrhagic diarrhea in pigs and modulates their intestinal microbiome. The development of an in vitro infection model that replicates in vivo features facilitated the observation of the initial events in "B. hampsonii" interaction with the colon. When explants were exposed to "B. hampsonii" similar histological lesions to in vivo were observed. This system provides a powerful model for future studies of the pathogenesis of "B. hampsonii" and other enteric pathogens of pigs
On time-varying collaboration networks
The patterns of scientific collaboration have been frequently investigated in
terms of complex networks without reference to time evolution. In the present
work, we derive collaborative networks (from the arXiv repository)
parameterized along time. By defining the concept of affine group, we identify
several interesting trends in scientific collaboration, including the fact that
the average size of the affine groups grows exponentially, while the number of
authors increases as a power law. We were therefore able to identify, through
extrapolation, the possible date when a single affine group is expected to
emerge. Characteristic collaboration patterns were identified for each
researcher, and their analysis revealed that larger affine groups tend to be
less stable
The Case of Latin American Countries
This dissertation examines the impact of renewable energy policies on carbon dioxide
emissions in Latin America region. Ten countries were analyzed in a period from 1991
to 2012, utilizing the methodology of autoregressive panel with distributed lag to
decompose the total effect in their repercussions in the short- and long-run. The
presence of cross-sectional dependence confirms that Latin American countries share
spatial patterns, as well as, the heteroskedasticity, contemporaneous correlation,
and first order autocorrelation cross-sectional dependence were identified.
Considering this violations, the robust dynamic Driscoll-Kraay estimator with fixed
effects that is robust to these phenomena was used. In the same way, it was
observed that the primary energy consumption per capita contributes in both the
short- and long-run, to increase in carbon dioxide emissions. The research proved
that the number of renewable energy policies in the long-run, and renewable
electricity generation per capita both in the short-and long-run, contribute to
mitigate per capita carbon dioxide emissions.Esta dissertação examina o impacto das políticas de energias renováveis nas emissões
de dióxido de carbono na região da América Latina. Foram analisados, dez países no
período compreendido entre 1991 a 2012, utilizando como metodologia o modelo
auto-regressivo, com desfasamentos distribuídos, para decompor o efeito total e as
suas repercussões a curto e longo prazo. Foi detetada a presença da dependência
transversal, confirmando que estes países compartilham os mesmos padrões
espaciais, bem como a presença de heterocedasticidade, correlação contemporânea
e autocorrelação de dependência transversal de primeira ordem. Tendo em atenção
estas infrações, foi utilizado o estimador dinâmico Driscoll-Kraay, com efeitos fixos,
que é robusto a estes fenómenos. De igual modo, se observou que o consumo de
energia primária per capita, contribui, tanto a curto como a longo prazo, para o
aumento das emissões de dióxido de carbono. A pesquisa comprovou que o número
de políticas e a geração a geração de energias renováveis contribuem para mitigar as
emissões de dióxido de carbono
TMPRSS2 e outras serino proteases transmembrana tipo II (TTSPS) : sinal de uma corrida armamentista de longo periodo entre vírus e mamíferos placentários
O gene da Serina Protease Transmembrana 2 (TMPRSS2), localizado no cromossomo 21q22.3, codifica uma proteína com o mesmo nome, sendo membro da família das Serino Proteases Transmembrana Tipo II (TTSPs). A TMPRSS2 humana é normalmente relacionada a resposta a andrógenos, mas foi cooptada pelo SARS-CoV-2 para clivar a glicoproteína viral Spike, e assim permitir a infecção da célula hospedeira. Apesar da existência de outras proteases cooptadas pelo SARS-CoV-2 para realizar essa função, recentes estudos funcionais mostram uma ativação e penetração mais velozes do SARS-CoV-2 em células expressando TMPRSS2 que naquelas dependentes de outras proteases. De forma a avaliar os padrões evolutivos que moldaram a relação entre a TMPRSS2 do Homo sapiens e a Spike do SARS-CoV-2, buscamos identificar todas as TTSPs presentes no genoma do Homo sapiens, visto que o último estudo sobre o tema foi publicado em 2009. Foram encontradas 18 TTSPs pertencentes a 4 subfamílias, resgatando a relação filogenética original das subfamílias TTSPs. Porém quando foram analizados somente os 30 sítios que interagem com a Spike do SARS-CoV-2 um padrão filogenético distinto foi encontrado. Também investigamos a região codificante dos ortólogos do TMPRSS2 de 182 espécies de mamíferos placentários. A variabilidade interespecífica em 33 sítios pode ser explicada por seleção positiva de acordo com a análise no pacote MEME, sendo que seis desses sítios (299, 340, 389, 413, 431, 438), ou seja, 15%, são reconhecidos como importantes para a interação com o vírus. Esses resultados podem indicar um sinal de uma corrida armamentista entre os coronavirus e os seus potenciais hospedeiros mamíferos. Em outras palavras, esse padrão de variação sugere que a maior parte da variação entre espécies seja resultados de pressões seletivas que potencialmente vêm moldando a função normal da TMPRSS2 humana e de seus ortólogos nas células das espécies correspondentes. Por outro lado, a Spike viral estaria sendo moldada evolutivamente para se ligar em posições nas proteases dos hospedeiros mamíferos com menos propensão a terem variação promovida por ação de seleção positiva, o que conferiria vantagem ao vírus, pois ele teria menos chance de perder afinidade com o hospedeiro ao mesmo tempo que daria mais chances para saltos zoonóticos.The Transmembrane Serine Protease 2 (TMPRSS2) gene, located at human chromosome 21q22.3, encodes a protein with the same name member from the type II transmembrane serine proteases (TTSPs). TMPRSS2 is usually related to the response to androgens but is co-opted by the SARS-CoV2 to cleave the viral Spike glycoprotein to infect the host cell. Despite the existence of other proteases co-opted by SARS-CoV2 to that function, recent functional studies show a more rapid activation and penetration of SARS-CoV2 in cells expressing TMPRSS2 than with those in which infection depends on other proteases. In order to assess the evolutionary patterns that shaped the relationship between the Homo sapiens TMPRSS2 and SARS-CoV2 Spike, we aimed to identify all TTSPs present in the Homo sapiens genome since the previous study with this purpose was published in 2009. One of our goals is to understand better why TMPRSS2 has been evolutionarily co-opted and is preferentially used to cleave Spike. Eighteen canonic Homo sapiens TTSPs, grouped in 4 clades were found, rescuing the original phylogenetic relationship of the TTSPs subfamilies. However, when only 30 sites that interact with the Spike of SARS-CoV-2 were used, a distinct phylogenetic pattern was found. We also investigated the coding region of TMPRSS2 orthologs of the 182 species of placental mammals. Using the MEME package, our evolutionary analysis shows that the interspecific variability in 33 sites can be explained by positive selection, six of them (299, 340, 389, 413, 431, 438), that is, 15%, with importance for the interaction with SARS- CoV-2. These results may be a sign of the biological arms race between coronaviruses and their potential mammalian hosts. In other words, this pattern of variation suggests that most of the variation between species is the result of selective pressures that have been shaping the normal function of human TMPRSS2 and its orthologs in the cells of the corresponding species. On the other hand, the virtal Spike would be evolutionarily shaped to bind at positions in the proteases of mammalian hosts that are less likely to have variation promoted by positive selection action, which would give the virus an advantage, as it would have less chance of losing affinity with the host while giving more chances for zoonotic jumps
State of the art of money laundering and corruption mitigation : the example of brazilian compliance with international standards
Mestrado em Economia Internacional e Estudos EuropeusO branqueamento de capitais e a corrupção estão profundamente ligados porque os rendimentos da corrupção devem ser branqueados e integrados no mercado. Estes crimes também têm uma dimensão internacional. Na ausência de cooperação e normas internacionais, o processo de luta contra o branqueamento de capitais e a mitigação da corrupção está em risco nas jurisdições nacionais. Esta tese apresenta o estado da arte neste domínio, nomeadamente, como as políticas anti-branqueamento de capitais podem prevenir a corrupção, com base no exemplo da jurisdição brasileira na sua aplicação de normas internacionais. O Brasil ganhou atenção com casos de corrupção como "Mensalão" ou "Lava Jato", que afetaram a forma como era percebida internacionalmente.
Analisamos primeiro os conceitos e contextos de corrupção, branqueamento de capitais e conformidade. Analisamos também vários documentos referenciados como Convenções e as "Quarenta Recomendações", uma vez que se tratam de códigos internacionais para criminalizar o branqueamento de capitais. Estes documentos permitiram o desenvolvimento do anti-branqueamento de capitais numa lógica de conformidade. Depois, usamos o Brasil como um exemplo prático para ilustrar como os padrões podem ser implementados, bem como os desafios associados. Ao destacar a importância de uma cultura de conformidade, esta tese contribui para a compreensão de como as normas internacionais podem ajudar um país a superar a corrupção e explicar o que pode falhar no processo de mitigação em resultado de desafios políticos e sociais nacionais.Money laundering and corruption are deeply connected because the proceeds from corruption must be laundered and integrated into the market. Those crimes also have an international dimension. In the absence of international cooperation and standards, the process of anti-money laundering and corruption mitigation is at risk in domestic jurisdictions. This thesis presents the state of the art in this field, namely, how anti-money laundering policies can prevent corruption, based on the example of Brazilian jurisdiction in its application of international standards. Brazil gained attention with corruption cases as "Mensalão" or "Lava Jato", which affected how it was perceived internationally.
We first analyse the concepts and contexts of corruption, money laundering, and compliance. We also analyse several referenced documents as Conventions and the Forty recommendations as these are international codes to criminalize money laundering. These documents allowed the development of anti-money laundering in a logic of compliance. Then, we use Brazil as a practical example to illustrate how standards can be implemented, as well as the associated challenges. By highlighting importance of a culture of compliance, this thesis contributes to the understanding of how international standards can help a country overcome corruption and to explain what can fail in the process of mitigation as a result of national political and societal behavioural challenges.info:eu-repo/semantics/publishedVersio
Economic Loss to the Brazilian Regions Due to the Doha Round Failure
We build a database and model to develop general equilibrium analysis of the Brazilian economy at the level of the five macro regions. The model is multiregional at global level as also at the Brazilian level. The project is coupled to the GTAP model through disaggregation of the original Brazilian input-output matrix and trade flows and follows the GTAPinGAMS structure and syntax to generate the General Equilibrium Analysis Project for the Brazilian Economy (PAEG). The regional database is that of the GTAP version 6 and represent the 2001 world economy. We aggregate the data in seven regions plus the five Brazilian sub-regions and nineteen commodities/sectors to apply the scenario Doha Round to determine the probable losses to the Brazilian regions from the failure of the Doha round of negotiations. It is analyzed cuts in the agricultural and manufactures (NAMA proposal) import tariffs via the application of the Swiss formula, reduction in the agricultural production subsidies and elimination of agricultural export subsidies. The results show that although the regions are affected in different ways, the Doha Round failure generates losses for all Brazilian regions. The losses are greater for the Midwest and South regions, the most important for the Brazilian agricultural production.Brazilian regions, General equilibrium, Agribusiness, Trade liberalization, International Development, International Relations/Trade, F13, F15, Q17,
THE HERITAGE OF EUROPEAN INTERNATIONAL SOCIETY IN MULTIDIMENSIONAL PEACE OPERATIONS: LIBERIA AS A CASE STUDY
The present paper has as its central objective to analyze United Nations (UN) peace operations as a form of creating post-conflict States that carries a series of institutions that underpins what is understood as the International Society, firstly consolidated by European states in previous centuries. I rely on English School’s historical perspective on International Society in order to demonstrate the transmission of certain institutions through multidimensional peace operations, briefly exposing the United Nations Mission in Liberia (UNMIL) case. By analyzing some primary documents concerning the mission that took place in Liberia, it is possible to infer that UN multidimensional peace operations promotes institutions built within a European and Western international order.Key words: English School; International Society; Peace Operations; United Nations; UNMIL.O presente trabalho tem como objetivo central analisar as operações de paz da Organização das Nações Unidas (ONU) como uma forma de criar Estados pós-conflito que carregam uma série de instituições que sustentam o que é entendido como Sociedade Internacional, primeiramente consolidada pelos europeus nos séculos anteriores. O artigo baseia-se na perspectiva histórica da Escola Inglesa sobre a Sociedade Internacional, a fim de demonstrar a transmissão de certas instituições através das operações de paz multidimensionais, expondo o caso UNMIL. Ao analisar alguns documentos primários relativos à missão que ocorreu na Libéria, é possível inferir que as operações de paz multidimensionais da ONU promovem instituições construídas dentro de uma ordem internacional europeia e ocidental.Palavres Chave: Escola Inglesa; Sociedade Internacional; Operações de Paz; Nações Unidas; UNMIL
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