F4 positive enterotoxigenic Escherichia coli (ETEC) is the most common pathogen causing neonatal diarrhea in piglets. The pathogenesis requires the attachment of ETEC to the intestinal brush border, mediated by F4 fimbria. Colostral anti-F4 antibodies and some non-immunoglobulin porcine skim milk proteins can bind F4 and prevent colonization and infection by F4-positive ETEC. Little is known, however, about the F4-binding ability of porcine milk fat globule membrane (MFGM) proteins. In addition, the knowledge of the absorption of porcine colostral proteins into the blood of neonatal piglets is limited, despite the well accepted concept that in neonatal piglets, protein absorption from the intestine is non-selective.<p> In this study, the ability of porcine MFGM proteins to bind purified F4ac (one of the three subtypes of F4 fimbriae) was investigated. Porcine MFGM proteins were first separated by 2D SDS-PAGE and subsequently identified by mass spectrometry. Overlay western Blot was then employed to demonstrate the interaction between porcine MFGM proteins and purified F4ac. Several proteins from porcine MFGM reacted with F4ac, and of these, lactadherin, butyrophilin, adipophilin, and acyl-CoA synthetase 3 reacted strongly. The biological function of these proteins in vivo was not investigated but it is possible that their interaction with F4ac positive ETEC interferes with bacterial attachment and colonization. In order to investigate protein absorption by neonatal piglets after natural suckling, the protein profiles of the plasma of pre-suckling and 24 h post-suckling neonatal piglets were studied by 2D SDS-PAGE. Those plasma proteins that increased prominently after suckling were then identified by mass spectrometry. Only immunoglobulins were unequivocally determined to be absorbed, because they were absent before suckling and present in large quantity in plasma 24 h after suckling. The absorption of other colostral proteins was either equivocal or not detectable by our detection methods. These results suggest that, unlike immunoglobulins, major non-immunoglobulin proteins in porcine colostrum may not be absorbed into systemic circulation in substantial amounts.

This paper examines the synchronization of business cycles across the G7 countries during US recessions since the 1870s. Using a dynamic measure of correlations, results depend on the globalization period under consideration. During the 2007-2009 recession, business cycles co-movements increased to unprecedented levels. (author's abstract)

The energy-momentum tensor (EMT) is the Noether current associated with translations. It is of interest because, first of all, it has physical meaning as it contains the energy density and the momentum density. Moreover, its trace can be related to the beta function so that the scaling behaviour of the theory at hand can be studied. We are particularly interested in the scaling behaviour of strongly coupled theories. To explore the strong coupling regime it is necessary to compute the EMT non-perturbatively, i.e. on the lattice. This complicates matters greatly. On the lattice translation invariance is broken which leads to additional terms in the translation Ward identity from which the EMT is derived. This results in turn in the need to renormalise the EMT on the lattice. In this thesis we extend recent studies on the renormalisation of the EMT in four-dimensional gauge theory to the case of a three-dimensional scalar theory to investigate its divergence structure and the numerical feasibility of the suggested procedure on a more basic level. Furthermore, scalar φ4-theory in three dimensions exhibits an infrared fixed point and can thus serve as a toy model to examine mechanisms for building theories beyond the standard model. Our strategy to renormalise the EMT on the lattice is to identify all possible terms that can mix with both sides of the translation Ward identity. The renormalised EMT is a combination of operators of the same or lower dimension obeying the symmetries of the theory. The mixing is determined by requiring that the renormalised EMT satisfies the correct Ward identities. Using different probes in the translation Ward identity one can compute the coefficients of the EMT by solving a linear system of equations. However, contact terms can arise. One solution is the recently introduced Wilson flow. Its renormalisation properties allow for expectation values free of contact terms. That way the Wilson flow provides for a meaningful theoretical formulation of the EMT on the lattice that can be used in practice. In this thesis we review the renormalisation properties and the phase diagram of scalar φ4-theory in three dimensions, the translation Ward identity and the EMT in the continuum, as well as the gradient flow for scalar theory. A large part is dedicated to the perturbative renormalisation of the EMT on the lattice. Finally, our strategy to compute the renormalisation constants of the EMT in scalar theory non-perturbatively is discussed in detail, and our results for the renormalisation constants are presented.

Numerical Stochastic Perturbation theory is a powerful tool for estimating high-order perturbative expansions in lattice quantum field theory. The standard algorithm based on the Langevin equation, however, suffers from several limitations which in practice restrict the potential of this technique: first of all it is not exact, a sequence of simulations with finer and finer discretization of the relevant equations have to be performed in order to extrapolate away the systematic errors in the results; and, secondly, the numerical simulations suffer from critical slowing down as the continuum limit of the theory is approached. In this thesis I investigate some alternative methods which improve upon the standard approach. In particular, I present a formulation of Numerical Stochastic Perturbation theory based on the Generalised Hybrid Molecular Dynamics algorithm and a study of the recently proposed Instantaneous Stochastic Perturbation Theory. The viability of these methods is investigated in φ4 theory.

Orientador: Domingos da Silva Leite / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-07T11:06:07Z (GMT). No. of bitstreams: 1 Valadares_GeorgioFreesz_D.pdf: 5633139 bytes, checksum: eb53d324f81f52cd2327efa730c3e888 (MD5) Previous issue date: 2006 / Resumo: Infecções por Escherichia coli são freqüentes em animais domésticos, afetando principalmente animais recém nascidos e no período do pós-desmame, sendo responsáveis por importantes danos econômicos na suinocultura e pecuária de bovinos e ovinos. A instalação da bactéria ao hospedeiro se dá através da colonização, processo mediado por proteínas denominadas adesinas, que se encontram distribuídas por toda a superfície bacteriana. Estas apresentam uma grande variedade morfológica e são coletivamente chamadas de Fatores de Colonização (FCs). Neste trabalho identificamos um novo fator de colonização (FC O25) presente em cepas de Escherichia coli isoladas de casos de colibacilose neonatal bovina, que apresenta semelhanças antigênicas com os FCs F4(K88), CS31A e F41 sem, contudo, apresentar identidade genética com estes fatores em ensaios de PCR. Baseados nessas homologias, investigamos a hipótese do FC O25 pertencer a esta família de FCs. Estudamos a seqüência do gene que compõe a subunidade principal do FC O25 com base em semelhanças com genes dos fatores de colonização homólogos e encontramos o FC O25 presente em 35 das 41 cepas em estudo. Verificamos que a proteína FC O25 apresenta 49,7% de homologia com a proteína FaeG (F4), 35,4% com ClpG (CS31A) e 29,4% com FimF41. Com ferramentas de bioinformática determinamos a relação filogenética entre essas proteínas e a estrutura secundária do FC O25. Os estudos de extração de DNA genômico e plasmidial indicaram que o gene FC O25 deve estar localizado no cromossomo bacteriano. Este foi clonado no vetor de expressão pET-151, inserido na linhagem de E.coli BL21[DE3]-Star e a proteína do FC O25 foi obtida e purificada e antissoro policlonal monoespecífico foi obtido em coelho. A proteína do FC O25 purificada foi submetida a ensaios de Western Blotting frente a antissoros anti os FCs F4, F41 e CS31A e verificamos reconhecimento da proteína em diferentes graus. A cepa CG1905-B foi utilizada em ensaios de microscopia eletrônica de transmissão com marcação por anticorpos conjugados com ouro e verificamos que a estrutura do FC O25 é do tipo fibrilar assemelhando-se à estrutura do CS31A. Em ensaios de adesão a linhagens de células eucarióticas in vitro observamos adesão às células Caco-2 (carcinoma de cólon humano) e que esta adesão era inibida pelo antissoro anti-FC O25. Os resultados sugerem que o FC O25 pode ser importante para a patogenicidade das E. coli bovinas no Brasil, uma vez que encontramos uma associação deste com outros fatores de colonização e, sobretudo com toxinas relacionadas com a patogenia em bovinos, evidenciando novas relações entre mecanismos de virulência que merecem novas investigações, além da própria elucidação completa da estrutura do operon FC O25 / Abstract: Infections from Escherichia coli are frequent in domestic animals, affecting mainly newborn animals in the post weaning period, being thus responsible for important economic losses in the cattle, porcine and lamb herds. The establishment of the bacterium in the host is made by colonization and it is a process mediated by proteins called adhesins that are distributed along the bacterial surface. They present a great morphological variety and are called Colonization factors (CFs). Our objective in this work was to identify the new colonization factor (CF O25) in Escherichia coli strains isolated from bovine neonatal colibacillosis, this CF O25 presents antigenic similarities with the FCs F4(K88), CS31A and F41 without, however, present genetic identity to these factors in PCR assays. Based in these homologies, we investigated the hypothesis of the NFC be a member of this "family" of CFs. So we studied the sequence of the CF O25¿s main subunit gene and its similarities with the genes of the homologous CFs (F4, F41 and CS31A) in polymerase chain reaction (PCR) assays. We found the CF O25 in 35 of the 41 studied strains. Through DNA sequencing, we verified that CF O25 protein presents 49.7% of homology with FaeG protein (F4), 35.4% with ClpG (CS31A) and 29.4% with FimF41. Using bioinformatics tools we determined the phylogenetic relationships between these proteins and the secondary structure of the CF O25. The genomic and plasmid DNA extraction assays indicates that the CF O25 gene is located in the bacterial chromosome. The CF O25 gene was cloned in the pET-151 expression vector, inserted in the E.coli BL21[DE3]-Star strain and the CF O25 protein was over expressed, purified and monospecific antiserum was obtained in rabbits. The purified CF O25 protein was submitted to Western Blotting assays with antissera against the FCs F4, F41 and CS31A and we verified recognition of the CF O25 in different degrees. The CG1905-B strain was used in the assays of electronic transmission microscopy using immunogold. The structure of the PCF is fibrillar resembling it the structure of the CS31A. This strain also was submitted the assays of adhesion to the eukaryotic culture cells and we observed adhesion to the Caco-2 cells (human colon carcinoma), this adhesion could be inhibited by anti-CFO25 antiserum. Our results suggest that the CF O25 can be important for the bovine pathogenicity of E. coli in Brazil, since we found CF O25 associated with other colonization factors and toxins, related with patogenicity in bovines, evidencing new relationships between virulence mechanisms that deserve new investigations, as well the elucidation of the complete structure of CF O25 operon / Doutorado / Microbiologia / Doutor em Genetica e Biologia Molecular

Les diarrhées post-sevrages causées par des infections à Escherichia coli entérotoxinogène positif pour le fimbriae F4 (ETEC F4), entraînent des pertes économiques importantes chez les producteurs de porc. Depuis quelques années, l’utilisation de probiotiques, comme additif alimentaire pour prévenir ce type d’infection entérique et réduire les traitements aux antimicrobiens, suscite un intérêt grandissant en production porcine. Le but du présent travail est de déterminer l’influence de l’administration des probiotiques Pediococcus acidilactici (PA) et Saccharomyces cerevisiae boulardii (SCB) sur la colonisation et l’attachement des ETEC F4, l’accumulation de fluide intestinal et l’expression de cytokines dans l’iléon de porcelets sevrés. Dès la naissance, différentes portées de porcelets ont été affectées aux traitements suivants : PA, SCB, PA + SCB, témoin et témoin avec antibiotiques (ATB). Une dose quotidienne de probiotiques (1 × 109 UFC) a été administrée aux porcelets des groupes probiotiques durant la lactation et après le sevrage. Sept jours après le sevrage, à 28 jours d’âge, des porcelets positifs pour le récepteur intestinal spécifique pour F4 ont été infectés oralement avec une souche ETEC F4. Les porcelets ont été euthanasiés 24 heures après l’infection (jour 29) et différents échantillons intestinaux ont été prélevés. Chez les porcelets recevant des probiotiques, l’attachement des ETEC F4 à la muqueuse iléale était significativement diminué chez les groupes PA ou SCB en comparaison avec le groupe ATB. Finalement, l’expression de cytokines intestinales était plus élevée chez les porcs du groupe PA + SCB en comparaison avec les porcelets témoins. En conclusion, les résultats de cette étude suggèrent que l’administration de probiotiques pourrait être une alternative pour limiter les infections à ETEC F4 chez le porc. / Postweaning diarrhea (PWD) associated with F4-positive enterotoxigenic Escherichia coli (ETEC F4) causes important economic losses in swine production. Since a couple of years, the use of probiotics as feed additives to prevent such enteric infections and reduce the use of antimicrobial treatments, has gained in interest. The aim of the present study is to evaluate the effects of Pediococcus acidilactici (PA) and Saccharomyces cerevisiae boulardii (SCB), on ETEC F4 colonization and attachment, accumulation of intestinal fluid and cytokines expression in weaned pig’s ileum. At birth, different litters of pigs were allocated to the following treatments: PA, SCB, PA + SCB, control (CTRL) and control with antibiotics (ATB). Probiotics (1 × 109 CFU) were administered daily to probiotics group during the lactation period and after weaning. One week after weaning, at 28 days of age, all F4-receptor-positive pigs were orally challenged with an ETEC F4 strain. Pigs were slaughter 24 hours later (day 29) and different intestinal samples were collected. In pigs treated with PA or SCB, the attachment of ETEC F4 to the ileal mucosa was significantly reduced in comparison with the ATB group. Finally, intestinal cytokines were upregulated in PA + SCB group in comparison with the CTRL group. In conclusion, these results suggest that administration of probiotics could be an alternative to attenuate ETEC F4 infection in pigs.

Les diarrhées post-sevrages causées par des infections à Escherichia coli entérotoxinogène positif pour le fimbriae F4 (ETEC F4), entraînent des pertes économiques importantes chez les producteurs de porc. Depuis quelques années, l’utilisation de probiotiques, comme additif alimentaire pour prévenir ce type d’infection entérique et réduire les traitements aux antimicrobiens, suscite un intérêt grandissant en production porcine. Le but du présent travail est de déterminer l’influence de l’administration des probiotiques Pediococcus acidilactici (PA) et Saccharomyces cerevisiae boulardii (SCB) sur la colonisation et l’attachement des ETEC F4, l’accumulation de fluide intestinal et l’expression de cytokines dans l’iléon de porcelets sevrés. Dès la naissance, différentes portées de porcelets ont été affectées aux traitements suivants : PA, SCB, PA + SCB, témoin et témoin avec antibiotiques (ATB). Une dose quotidienne de probiotiques (1 × 109 UFC) a été administrée aux porcelets des groupes probiotiques durant la lactation et après le sevrage. Sept jours après le sevrage, à 28 jours d’âge, des porcelets positifs pour le récepteur intestinal spécifique pour F4 ont été infectés oralement avec une souche ETEC F4. Les porcelets ont été euthanasiés 24 heures après l’infection (jour 29) et différents échantillons intestinaux ont été prélevés. Chez les porcelets recevant des probiotiques, l’attachement des ETEC F4 à la muqueuse iléale était significativement diminué chez les groupes PA ou SCB en comparaison avec le groupe ATB. Finalement, l’expression de cytokines intestinales était plus élevée chez les porcs du groupe PA + SCB en comparaison avec les porcelets témoins. En conclusion, les résultats de cette étude suggèrent que l’administration de probiotiques pourrait être une alternative pour limiter les infections à ETEC F4 chez le porc. / Postweaning diarrhea (PWD) associated with F4-positive enterotoxigenic Escherichia coli (ETEC F4) causes important economic losses in swine production. Since a couple of years, the use of probiotics as feed additives to prevent such enteric infections and reduce the use of antimicrobial treatments, has gained in interest. The aim of the present study is to evaluate the effects of Pediococcus acidilactici (PA) and Saccharomyces cerevisiae boulardii (SCB), on ETEC F4 colonization and attachment, accumulation of intestinal fluid and cytokines expression in weaned pig’s ileum. At birth, different litters of pigs were allocated to the following treatments: PA, SCB, PA + SCB, control (CTRL) and control with antibiotics (ATB). Probiotics (1 × 109 CFU) were administered daily to probiotics group during the lactation period and after weaning. One week after weaning, at 28 days of age, all F4-receptor-positive pigs were orally challenged with an ETEC F4 strain. Pigs were slaughter 24 hours later (day 29) and different intestinal samples were collected. In pigs treated with PA or SCB, the attachment of ETEC F4 to the ileal mucosa was significantly reduced in comparison with the ATB group. Finally, intestinal cytokines were upregulated in PA + SCB group in comparison with the CTRL group. In conclusion, these results suggest that administration of probiotics could be an alternative to attenuate ETEC F4 infection in pigs.

This diploma thesis is devoted to the multivariate cryptosystems. It includes an overview of commutative algebra with emphasis on Gröbner bases. Of all algorithms, especially the ones using Gröbner bases are studied, i.e. Buchberger's algorithm, which is already implemented in Wolfram Mathematica, and F4 algorithm, for which a program package has been created in the Wolfram Mathematica environment. Also Zhuang-Zi algorithm is described. To simplify its steps a program to compute the Lagrange interpolation polynomial has been created in Python.

This paper gives an overview on the research done in the fields of tax competition, coordination and harmonisation. The survey is divided in two main parts, in the first section we compare the standard tax competition literature that sees tax competition as a bad, to public choice contributions that advocate tax reductions. In the second part we consider theories of endogenous growth, which focus on analysing the taxation question. After introducing the fundamental contributions, we discuss extensions in the line of an open economy, an OLG setting and the transitional dynamics in greater detail. (author's abstract) / Series: Discussion Papers SFB International Tax Coordination

The paper provides an explanation of the mechanisms underlying trade roots of the contagion effects emanating from the recent turmoils. It is argued that under demand uncertainty risk averse behavior of firms provides a basis for international trade. The paper shows by means of a simple two-country model that risk averse firms operating in perfectly competitive markets with uncertainty of demand tend to diversify markets what gives a basis for international trade in identical commodities even between identical countries. It is shown that such trade may be welfare improving despite efficiency losses due to cross-hauling and transportation costs. The analysis reveals that change of the expectations concerning market conditions caused by the turmoil in the neighbor country (i.e., shift in the perception of market conditions) may lead to macroeconomic destabilization (increase in price level and unemployment, worsening of terms of trade, and deterioration of trade balance). / Series: Discussion Papers of the Institute for Economic Geography and GIScience