Generalized Geometry and Partial Supersymmetry Breaking

This review article consists of two parts. In the first part we use the formalism of (exceptional) generalized geometry to derive the scalar field space of SU(2)xSU(2)-structure compactifications. We show that in contrast to SU(3)xSU(3) structures, there is no dynamical SU(2)xSU(2) structure interpolating between an SU(2) structure and an identity structure. Furthermore, we derive the scalar manifold of the low-energy effective action for consistent Kaluza-Klein truncations as expected from N=4 supergravity. In the second part we then determine the general conditions for the existence of stable Minkowski and AdS N=1 vacua in spontaneously broken gauged N=2 supergravities and construct the general solution under the assumption that two appropriate commuting isometries exist in the hypermultiplet sector. Furthermore, we derive the low-energy effective action below the scale of partial supersymmetry breaking and show that it satisfies the constraints of N=1 supergravity. We then apply the discussion to special quaternionic-Kahler geometries which appear in the low-energy limit of SU(3)xSU(3)-structure compactifications and construct Killing vectors with the right properties. Finally we discuss the string theory realizations for these solutions.Comment: 117 pages, Ph.D. thesis (Advisor: Jan Louis); v2: references adde

To respond or not to respond - a personal perspective of intestinal tolerance

For many years, the intestine was one of the poor relations of the immunology world, being a realm inhabited mostly by specialists and those interested in unusual phenomena. However, this has changed dramatically in recent years with the realization of how important the microbiota is in shaping immune function throughout the body, and almost every major immunology institution now includes the intestine as an area of interest. One of the most important aspects of the intestinal immune system is how it discriminates carefully between harmless and harmful antigens, in particular, its ability to generate active tolerance to materials such as commensal bacteria and food proteins. This phenomenon has been recognized for more than 100 years, and it is essential for preventing inflammatory disease in the intestine, but its basis remains enigmatic. Here, I discuss the progress that has been made in understanding oral tolerance during my 40 years in the field and highlight the topics that will be the focus of future research

Evidence for the classical integrability of the complete AdS(4) x CP(3) superstring

We construct a zero-curvature Lax connection in a sub-sector of the superstring theory on AdS(4) x CP(3) which is not described by the OSp(6|4)/U(3) x SO(1,3) supercoset sigma-model. In this sub-sector worldsheet fermions associated to eight broken supersymmetries of the type IIA background are physical fields. As such, the prescription for the construction of the Lax connection based on the Z_4-automorphism of the isometry superalgebra OSp(6|4) does not do the job. So, to construct the Lax connection we have used an alternative method which nevertheless relies on the isometry of the target superspace and kappa-symmetry of the Green-Schwarz superstring.Comment: 1+26 pages; v2: minor typos corrected, acknowledgements adde

Multimodal prediction of Alzheimer's disease severity level based on resting-state EEG and structural MRI

While several biomarkers have been developed for the detection of Alzheimer's disease (AD), not many are available for the prediction of disease severity, particularly for patients in the mild stages of AD. In this paper, we explore the multimodal prediction of Mini-Mental State Examination (MMSE) scores using resting-state electroencephalography (EEG) and structural magnetic resonance imaging (MRI) scans. Analyses were carried out on a dataset comprised of EEG and MRI data collected from 89 patients diagnosed with minimal-mild AD. Three feature selection algorithms were assessed alongside four machine learning algorithms. Results showed that while MRI features alone outperformed EEG features, when both modalities were combined, improved results were achieved. The top-selected EEG features conveyed information about amplitude modulation rate-of-change, whereas top-MRI features comprised information about cortical area and white matter volume. Overall, a root mean square error between predicted MMSE values and true MMSE scores of 1.682 was achieved with a multimodal system and a random forest regression model

A paramutation phenomenon is involved in the genetics of maize low phytic acid1-241 (lpa1-241) trait

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Phenylpropanoid Glycoside Analogues: Enzymatic Synthesis, Antioxidant Activity and Theoretical Study of Their Free Radical Scavenger Mechanism

Phenylpropanoid glycosides (PPGs) are natural compounds present in several medicinal plants that have high antioxidant power and diverse biological activities. Because of their low content in plants (less than 5% w/w), several chemical synthetic routes to produce PPGs have been developed, but their synthesis is a time consuming process and the achieved yields are often low. In this study, an alternative and efficient two-step biosynthetic route to obtain natural PPG analogues is reported for the first time. Two galactosides were initially synthesized from vanillyl alcohol and homovanillyl alcohol by a transgalactosylation reaction catalyzed by Kluyveromyces lactis β-galactosidase in saturated lactose solutions with a 30%–35% yield. To synthesize PPGs, the galactoconjugates were esterified with saturated and unsaturated hydroxycinnamic acid derivatives using Candida antarctica Lipase B (CaL-B) as a biocatalyst with 40%–60% yields. The scavenging ability of the phenolic raw materials, intermediates and PPGs was evaluated by the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) method. It was found that the biosynthesized PPGs had higher scavenging abilities when compared to ascorbic acid, the reference compound, while their antioxidant activities were found similar to that of natural PPGs. Moreover, density functional theory (DFT) calculations were used to determine that the PPGs antioxidant mechanism proceeds through a sequential proton loss single electron transfer (SPLET). The enzymatic process reported in this study is an efficient and versatile route to obtain PPGs from different phenylpropanoid acids, sugars and phenolic alcohols

Excesso de peso e ambiente de trabalho no setor público municipal

RESUMO Objetivo: Identificar se características sociodemográficas, hábitos alimentares, situação de saúde e condições de trabalho estão relacionadas ao excesso de peso em servidores e empregados públicos municipais. Métodos: Inquérito epidemiológico eletrônico (online) com servidores do município de Belo Horizonte, Minas Gerais, de setembro a dezembro de 2009. Investigaram-se informações sociodemográficas, de saúde, hábitos relacionados à alimentação e nutrição e informações sobre condições e ambiente de trabalho. Foi realizada análise de Regressão de Poisson (p<0,05), ajustada por sexo, idade e tempo do funcionário na função. Resultados: Um total de 44,4% dos participantes (n=4.893) apresentou sobrepeso, que prevaleceu em mulheres (p<0,001) e pessoas com maior mediana de idade (p<0,001), com filhos (p<0,001), casadas ou em união estável (p=0,002), e com menor nível educacional (p<0,001) e status ocupacional (p<0,001), determinados pelo International Socio-Economic Index. A regressão de Poisson encontrou associação entre sobrepeso e auto-relato de diabetes mellitus (RP=1,15; IC95%=1,03-1,27), hipercolesterolemia (RP=1,24; IC95%=1,15-1,32), hipertensão arterial (RP=1,47; IC95%=1,37-1,58), autoavaliação de saúde (RP=1,20; IC95%=1,12-1,29), cozinhar habitualmente (RP=1,11; IC95%CI=1,04-1,20), consumir carne com gordura aparente (RP=1,16; IC95%=1,08-1,24), e frequentemente não pausar durante o trabalho (RP=1,10; IC95%=1,03-1,18). Conclusão: A relação entre ambiente de trabalho e excesso de peso, evidenciada pela associação com a privação de pausa no trabalho, denota a necessidade de medidas preventivas específicas que considerem as características do ambiente de trabalho