Pneumocéfalo Espontâneo Hipertensivo

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CP4 miracle: shaping Yukawa sector with CP symmetry of order four

We explore the phenomenology of a unique three-Higgs-doublet model based on the single CP symmetry of order 4 (CP4) without any accidental symmetries. The CP4 symmetry is imposed on the scalar potential and Yukawa interactions, strongly shaping both sectors of the model and leading to a very characteristic phenomenology. The scalar sector is analyzed in detail, and in the Yukawa sector we list all possible CP4-symmetric structures which do not run into immediate conflict with experiment, namely, do not lead to massless or mass-degenerate quarks nor to insufficient mixing or CP-violation in the CKM matrix. We show that the parameter space of the model, although very constrained by CP4, is large enough to comply with the electroweak precision data and the LHC results for the 125 GeV Higgs boson phenomenology, as well as to perfectly reproduce all fermion masses, mixing, and CP violation. Despite the presence of flavor changing neutral currents mediated by heavy Higgs scalars, we find through a parameter space scan many points which accurately reproduce the kaon CP-violating parameter $\epsilon_K$ as well as oscillation parameters in K and $B_{(s)}$ mesons. Thus, CP4 offers a novel minimalistic framework for building models with very few assumptions, sufficient predictive power, and rich phenomenology yet to be explored.Comment: 39 pages, 8 figures, 1 table; v2: expanded discussion, extra references, matches published versio

Constraints on leptogenesis from a symmetry viewpoint

It is shown that type I seesaw models based on the standard model Lagrangian extended with three heavy Majorana right-handed fields do not have leptogenesis in leading order, if the symmetries of mass matrices are also the residual symmetry of the Lagrangian. In particular, flavor models that lead to a mass-independent leptonic mixing have a vanishing leptogenesis CP asymmetry. Based on symmetry arguments, we prove that in these models the Dirac-neutrino Yukawa coupling combinations relevant for leptogenesis are diagonal in the physical basis where the charged leptons and heavy Majorana neutrinos are diagonal.Comment: 5 pages; a few comments added; final version to appear in Phys. Rev.

Uniqueness of the Fock quantization of a free scalar field on S1S^1 with time dependent mass

We analyze the quantum description of a free scalar field on the circle in the presence of an explicitly time dependent potential, also interpretable as a time dependent mass. Classically, the field satisfies a linear wave equation of the form $\ddot{\xi}-\xi"+f(t)\xi=0$. We prove that the representation of the canonical commutation relations corresponding to the particular case of a massless free field ($f=0$) provides a unitary implementation of the dynamics for sufficiently general mass terms, $f(t)$. Furthermore, this representation is uniquely specified, among the class of representations determined by $S^1$-invariant complex structures, as the only one allowing a unitary dynamics. These conclusions can be extended in fact to fields on the two-sphere possessing axial symmetry. This generalizes a uniqueness result previously obtained in the context of the quantum field description of the Gowdy cosmologies, in the case of linear polarization and for any of the possible topologies of the spatial sections.Comment: 13 pages, typos corrected, version accepted for publication in Physical Review

Higher education methodologies: from urban planning to mathematical issues

This article will be focused on higher education learning and teaching methodologies, based on the experience of the Master Degree in Civil Engineering at the University of Beira Interior, in Covilhã (Portugal). It aims to present the results of the practises used by scholar of urban planning and mathematical issues, both regarding the civil engineering research field. Actually, there are some similarities in between the research process features of urban planning domain and mathematics field in order to promote the students’ success. In fact, these both scientific subjects follow analogous tasks in their research processes, not only regarding the same starting point which is the definition of the research problem, but also observing the final phase, which is based on the findings of results, or the proposed solution. It joins scholars from the department of civil engineering and architecture, experts in spatial analysis and scholars from the department of mathematics of the University of Beira Interior (UBI). One case study will be presented as an example and pioneer research of the application of these methodological approaches. It will be focused on the urban planning experiences, associated with postgraduate teachings. It is related to a PhD thesis in Civil Engineering focused on urban planning issues.info:eu-repo/semantics/publishedVersio

Strategies to obtain designer polymers based on cyanobacterial extracellular polymeric substances (EPS)

Biopolymers derived from polysaccharides are a sustainable and environmentally friendly alternative to the synthetic counterparts available in the market. Due to their distinctive properties, the cyanobacterial extracellular polymeric substances (EPS), mainly composed of heteropolysaccharides, emerge as a valid alternative to address several biotechnological and biomedical challenges. Nevertheless, biotechnological/biomedical applications based on cyanobacterial EPS have only recently started to emerge. For the successful exploitation of cyanobacterial EPS, it is important to strategically design the polymers, either by genetic engineering of the producing strains or by chemical modification of the polymers. This requires a better understanding of the EPS biosynthetic pathways and their relationship with central metabolism, as well as to exploit the available polymer functionalization chemistries. Considering all this, we provide an overview of the characteristics and biological activities of cyanobacterial EPS, discuss the challenges and opportunities to improve the amount and/or characteristics of the polymers, and report the most relevant advances on the use of cyanobacterial EPS as scaffolds, coatings, and vehicles for drug delivery.This work was financed by FEDER—Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 - Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by Portuguese funds through FCT—Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior in the framework of the project POCI-01-0145-FEDER-028779, contract DL57/2016/CP1327/CT0007 and fellowship SFRH/BD/119920/2016

The role of Social Capital towards resource sharing in collaborative R&D projects: Evidences from the 7th Framework Programme

This study examines the role of Social capital dimensions towards resource sharing within R&D cooperation projects funded by the 7th Framework Programme (FP7). Data were collected in a survey of 553 FP7 project participants and analysed using two different social network analysis (SNA) methodologies: Logistic regression quadratic assignment procedure and exponential random graph models. Results showed that all Social Capital dimensions helped to explain partners' resource sharing, although to a different extent. Prior ties were often significant, whilst shared vision and commitment were very frequently positive contributors to resource sharing. Trust was rarely significant, and occasionally detrimental, to partners' resource sharing. Therefore, the FP7 provided a collaborative but opportunistic environment for public and private actors. The novelty of this study derives from the combination of social capital theory with SNA to study intra-project partner relationships, contributing to a better understanding on the diversity of partner relationships within R&D projects.FCT doctoral grant (SFRH/BD/68802/2010) with funds from POPH/National Strategic Reference Framework, subsidized by the European Social Fund and MEC funds, and by FCT/MEC through Portuguese funds (PIDDAC)-PEst-OE/BIA/UI4050/2014info:eu-repo/semantics/publishedVersio

Conjugacy and geometry I : foot of the perpendicular, distance and gram determinant

In this note on space geometry, the Gram determinant is used for expressing distances, vectors whose magnitude equals those distances and best approximation points. Three cases are considered: distances from a point to a line and to a plane and distances between two skew lines. (Symbolic) determinants occur in the expressions of the feet of perpendiculars and in the representation of the vectors materializing the distances. Because best approximation problems often require the use of subspaces, in order to solve the general cases of the proposed problems, we make extensive use of the conjugacy principle much present in Mathematics. The main purpose of this paper, focused on the resolution of distance problems in tridimensional geometry, is to provide the acquisition of spatial abilities through the proposed constructive approach. The obtained results, which could be a starting point and give clues for solving more advanced geometry problems, are applicable in several fields of practical sciences, such as the Coordinate Metrology, for instance. Moreover, this paper may be a window for coming across with a diversity of scalar products.info:eu-repo/semantics/publishedVersio

Intrahepatic Colangiocarcinoma

Introdução: o colangiocarcinoma intra-hepático (CCIhp) é um tumor maligno raro, normalmente diagnosticado num estadio avançado. São objectivos deste estudo avaliar os resultados da terapêutica do CCIhp e os factores prognósticos com significado estatístico na sobrevida de doentes com esta entidade nosológica tratados no nosso Serviço. Material e métodos: Vinte e um doentes submetidos a tratamento por CCIhp nos últimos anos, dos quais onze foram operados com intuitos curativos: quatro hepatectomias esquerdas, duas hepatectomias esquerdas alargadas aos segmentos V e VIII, duas hepatectomias direitas, duas bissegmentectomias e uma trissegmentectomia. Resultados: a mortalidade per-operatória foi de 0% e a pós-operatória (três meses) de 6%. As sobrevidas cumulativas aos 5 anos foram de 14% no total da população, 26% nos doentes submetidos a cirurgia com intuitos curativos e 26% para a sobrevida cumulativa livre de doença. Observou-se recidiva tumoral hepática em cinco doentes, a qual ocorreu aos 1,09 ± 0,82 anos (limites: 0,24-2,08). Os factores que influenciaram a sobrevida da globalidade dos doentes foram o tratamento cirúrgico com intuitos curativos (p=0,028), a presença de invasão vascular (p=0,002) e o valor da fosfatase alcalina no momento do diagnóstico (p=0,044). Entre os doentes operados com intuitos curativos, a presença de invasão vascular influenciou a sobrevida global (p=0,025) e a sobrevida livre de doença (p=0,002). Conclusões: A ressecção cirúrgica com intuitos curativos aumentou, de forma estatisticamente significativa, a sobrevida dos doentes com CCIhp. No entanto, sendo o diagnóstico geralmente tardio, apenas uma pequena percentagem destes doentes pode beneficiar deste tratamento.info:eu-repo/semantics/publishedVersio

Coca-Cola - a model of transparency in research partnerships? A network analysis of Coca-Cola's research funding (2008-2016).

OBJECTIVE: To (i) evaluate the extent to which Coca-Cola's 'Transparency Lists' of 218 researchers that it funds are comprehensive; (ii) map all scientific research acknowledging funding from Coca-Cola; (iii) identify those institutions, authors and research topics funded by Coca-Cola; and (iv) use Coca-Cola's disclosure to gauge whether its funded researchers acknowledge the source of funding. DESIGN: Using Web of Science Core Collection database, we retrieved all studies declaring receipt of direct funding from the Coca-Cola brand, published between 2008 and 2016. Using conservative eligibility criteria, we iteratively removed studies and recreated Coca-Cola's transparency lists using our data. We used network analysis and structural topic modelling to assess the structure, organization and thematic focus of Coca-Cola's research enterprise, and string matching to evaluate the completeness of Coca-Cola's transparency lists. RESULTS: Three hundred and eighty-nine articles, published in 169 different journals, and authored by 907 researchers, cite funding from The Coca-Cola Company. Of these, Coca-Cola acknowledges funding forty-two authors (<5 %). We observed that the funded research focuses mostly on nutrition and emphasizes the importance of physical activity and the concept of 'energy balance'. CONCLUSIONS: The Coca-Cola Company appears to have failed to declare a comprehensive list of its research activities. Further, several funded authors appear to have failed to declare receipt of funding. Most of Coca-Cola's research support is directed towards physical activity and disregards the role of diet in obesity. Despite initiatives for greater transparency of research funding, the full scale of Coca-Cola's involvement is still not known