1,377 research outputs found

    The effects of explicit chiral symmetry breaking multiquark interactions on the spin 0 and 1 meson nonets: the ruling of the vector mesons

    Full text link
    We have recently extended the scalar-pseudoscalar sector of a generalized NJL Lagrangian that includes all NLO non derivative interactions in Nc counting (including explicit symmetry breaking ones) in order to incorporate the spin 1 mesons in the low-lying ground state of QCD [1]. Upon bosonization, the well known mixing of the scalar-vector and of the pseudoscalar- axial-vector fields occurs in the quadratic part of the Lagrangian. We show that a linearized diagonalization of these terms can be effected in a completely general way without compromising the underlying symmetries of the Lagrangian [2]. The resulting spin 1 mass spectra evidence a relation involving only the vector and axial-vector meson masses and the constituent quark masses. We discuss the dominant role of this relation in the fits and we show that the model may be fitted to accommodate to a very good accuracy the 4 low-lying meson spectra.Comment: 5 pages, 3 tables; based on a talk given at Hadron 2017, Salamanc

    A imagem, o texto e as aldeias

    Get PDF
    Eug√©ne Smith, norte-americano, fot√≥grafo, Jorge Dias, portugu√™s, antrop√≥logo, escritor, consumaram, quase ao mesmo tempo, um processo de an√°lise de duas comunidades rurais distintas, que viriam a tornar-se famosas de cada um dos lados da fronteira terrestre que nos √© mais pr√≥xima:. A presente comunica√ß√£o tem por objectivo, al√©m de servir de evoca√ß√£o e efem√©ride, efectuar uma compara√ß√£o entre as duas formas de comunica√ß√£o que deram a conhecer, √† sua maneira, as aldeias: a linguagem ic√≥nica e a linguagem verbal. Pretende-se introduzir alguns dados de reflex√£o e debate face √† for√ßa da imagem na modernidade, que, em v√°rios casos, s√≥ por si, consegue suplantar outras formas de comunica√ß√£o estabelecidas e aparentemente melhor estruturadas. Problematizar, talvez, se os efeitos lobrigados na reportagem de Eug√©ne Smith seriam hoje igualmente eficazes. Nesta comunica√ß√£o ser√£o ainda revelados alguns dados hist√≥ricos e recolhidos actualmente no terreno, angariados para refor√ßar os prop√≥sitos enunciados, e tamb√©m o perfil de milit√Ęncia humana, social e pol√≠tica dos seus autores

    Textbooks, image analysis from the perspective of social semiotics

    Get PDF
    O presente trabalho traduz resultados e reflex√Ķes da an√°lise efectuada a uma amostra de 525 imagens extra√≠das de 7 manuais escolares da disciplina de Ci√™ncias da Natureza do 6¬ļ ano de escolaridade do Ensino B√°sico, utilizando uma metodologia de an√°lise de imagens segundo a perspectiva de Kress & Leeuwen (1996), gram√°tica do ‚Äúdesign‚ÄĚ visual, inserida no contexto da semi√≥tica social, devotada esta a extrair significados que procuram expandir a mera considera√ß√£o formal e morfol√≥gica das imagens e que podem ser pertinentes equacionar sob o ponto de vista da did√°ctica e tecnologia educativa. Procura-se estabelecer bases para compreender se existe correla√ß√£o entre o maior ou menor sucesso de vendas das editoras de manuais escolares consideradas e determinadas caracter√≠sticas que essas mesmas imagens possuam. Os resultados da an√°lise esclarecem que as editoras que mais vendem obt√©m, de um modo geral, melhores pontua√ß√Ķes nas vari√°veis das imagens consideradas, face aos manuais menos vendidos. This study reflects results and reflections from the analysis of a sample of 525 images taken from seven textbooks in the discipline of Natural Sciences in the 6th year of basic school, using a method of image analysis from the perspective of Kress & Leeuwen (1996) , Grammar of " visual design " into the context of social semi√≥tica, devoted to this extract meanings that seek to expand the mere consideration of formal and morphological images that may be relevant to equate the point of view of teaching and educational technology. An attempt to establish the basis to understand the correlation between the more or less successful sales of publishers of textbooks and considered certain characteristics that have these same images. The analysis results clarify that publishers who sell more get, in general, high scores on the variables of the images considered, compared with less manual sold

    A general framework to diagonalize vector--scalar and axial-vector--pseudoscalar transitions in the effective meson Lagrangian

    Get PDF
    A new mathematical framework for the diagonalization of the nondiagonal vector--scalar and axial-vector--pseudoscalar mixing in the effective meson Lagrangian is described. This procedure has unexpected connections with the Hadamard product of n√ónn\times n matrices describing the couplings, masses, and fields involved. The approach is shown to be much more efficient as compared with the standard methods employed previously. The difference is especially noticeable if the chiral symmetry is broken explicitly. The paper ends with an illustrative application to the chiral model with broken SU(3)L√óSU(3)RSU(3)_L\times SU(3)_R symmetry.Comment: 16 page

    Problemas de identidade e comunicação nos manuais escolares da actualidade

    Get PDF
    Neste estudo e reflex√Ķes decorrentes do doutoramento efectuado pelo autor no bi√©nio de 2003/2004 defendido na UTAD em Novembro de 2008, √© analisada a forma de comunica√ß√£o verbo-ic√≥nica numa amostra representativa dos manuais escolares de Ci√™ncias da Natureza do 6¬ļ ano de escolaridade, adoptados pelas escolas p√ļblicas e privadas do pa√≠s e que foram adoptados durante v√°rios anos. Visa-se denunciar alguns problemas de concretiza√ß√£o que perturbam a identifica√ß√£o da mensagem did√°ctica e podem influenciar a pr√≥pria percep√ß√£o do eu (aluno) e do envolvimento com o qual os conte√ļdos se relacionam: Problemas de identidade face √† caracteriza√ß√£o de g√©nero e de ra√ßa, de contexto geogr√°fico e local; problemas de ambiguidade formal e legibilidade; problemas de veicula√ß√£o err√≥nea ou desfocada de conte√ļdos; problemas na articula√ß√£o verbo-ic√≥nica

    Merging traditional livelihood activities with new employment opportunities brought by ecotourism to Iona national park, Angola: rethinking social sustainability

    Get PDF
    Ecotourism activities and investment projects have been consistently increasing worldwide over the last few decades. In this process, ecotourism has contributed to fight poverty, to create local employment opportunities and to promote nature conservation. However, there are also plenty examples of nature-base tourism destinations where ecotourism principles have been distorted and negative impacts are on the rise. Therefore, studies that provide a deep understanding of the roots and consequences of those both positive and negative impacts are needed to achieve new higher tourism quality standards, to foster a sound local development and to promote an integrated and sustainable national growth. To obtain information useful to contribute specific recommendations aimed at linking tourism employers and job seekers, we have conducted a survey addressing locals’ demographic characteristics and their engagement in traditional livelihood activities. Data gathered from 202 respondents showed that in the largest villages traditional livelihood activities, excepting pastoralism, tend to have little expression while the same activities seem to play a key role in some small communities. Striking differences were found between nomadic or semi-nomadic people and people who have been assimilated into the western civilization and also have more sedentary life styles. Using this information and taking in consideration some new employment opportunities brought nature-based tourism to the Iona National Park, we have identified specific demographic profiles more suited for part-time and full-time jobs

    O neg√≥cio atl√Ęntico : as redes comerciais portuenses e as novas geografias do trato internacional (s√©culos XVI-XVII)

    Get PDF
    This work introduces the part played by the Portuguese Northwest centres in the construction of the Atlantic system due to the international traffic developed from its ports. One discusses here traditional historiographical interpretations, namely in what concerns the amplitude of the trade developed in the beginning of the Early Modern Period by commercial agents who can be positioned outside the Iberian imperial schemes, and the centrality of the economic spaces in the same period

    Nas origens de uma Resp√ļblica mar√≠tima e mercantil : o acolhimento ao estrangeiro nos portos medievais e modernos

    Get PDF
    Na constitui√ß√£o das identidades mar√≠timas o acolhimento ao estrangeiro nos portos medievais e modernos constituiu um elemento central; numa perspectiva comparada, este estudo procura mostrar a forma como os portos portugueses foram locais de experi√™ncias de contacto que enriqueceram os seus quotidianos e influenciaram comportamentos. Debatem-se quest√Ķes de relacionamento entre o ¬ęOutro¬Ľ e o ¬ęEu¬Ľportu√°rios e rev√™em-se conceitos muitas vezes utilizados de forma anacr√≥nica, como o de ¬ęna√ß√£o¬Ľ ou ¬ęxenofobia¬Ľ.In the constitution of medieval and early modern maritime identities, welcoming the foreigner in ports was a key-element; in a comparative perspective, this study seeks to show how the Portuguese portsdeveloped experiences of contact that enriched and influenced their everyday behaviours.The paper suggests new interpretations of the relations between the ¬ęSelf¬Ľ and the ¬ęOther¬Ľ, and reviews concepts often misused such as the ones of ¬ęnation¬Ľ or ¬ęxenophobia¬Ľ

    Caraterização de vírus específicos de insetos: análise da sua diversidade genética e relação com outros vírus

    Get PDF
    Os arbov√≠rus s√£o respons√°veis por doen√ßas com impacto significativo na sa√ļde humana, sendo transmitidos a humanos e outros animais por insetos e outros vetores invertebrados. Entre estes √ļltimos, os mosquitos representam um dos mais importantes vetores conhecidos por servirem de vetores a arbov√≠rus patog√©nicos para os humanos, de que s√£o exemplos os v√≠rus da dengue e Zika. Por muito tempo, a pesquisa de v√≠rus foi impulsionada pelo impacto que estes agentes imp√Ķem √† sa√ļde humana/animal/plantas, mas os desenvolvimentos nas √ļltimas d√©cadas nos dom√≠nios das tecnologias de sequencia√ß√£o de alto rendimento e bioinform√°tica permitiram melhorias nas estrat√©gias de descoberta de v√≠rus, o que, por sua vez, levou a um aumento no n√ļmero de v√≠rus peculiares que vieram a ser descobertos em rastreios virol√≥gicos, alguns com replica√ß√£o restrita em c√©lulas de vertebrados. Acredita-se que esses v√≠rus, designados v√≠rus espec√≠ficos de insetos, tenham impacto nulo ou baixo na sa√ļde animal e, provavelmente por isso mesmo, tenham permanecido √† sombra de arbov√≠rus patog√©nicos. No entanto, nas √ļltimas d√©cadas eles tornaram-se no foco da nossa aten√ß√£o, n√£o apenas pela sua extensa diversidade e estrat√©gias incomuns de replica√ß√£o restrita nalguns hospedeiros, mas tamb√©m pelo seu potencial de interferir na replica√ß√£o de arbov√≠rus. Desde ent√£o, diversos v√≠rus espec√≠ficos de insetos foram descobertos em v√°rias fam√≠lias de v√≠rus, com v√≠rus espec√≠ficos de mosquitos associados especialmente √†s fam√≠lias Flaviviridae, Mesoniviridae e Parvoviridae. Neste projeto procurou-se detetar e analisar novas sequ√™ncias de v√≠rus espec√≠ficos de insetos dessas tr√™s fam√≠lias virais em mosquitos coletados em Portugal, Angola e Mo√ßambique. A diversidade gen√©tica, reconstru√ß√£o filogen√©tica e avalia√ß√Ķes filodin√Ęmicas foram ent√£o executadas, usando tanto sequ√™ncias gen√≥micas geradas de novo, bem como de sequ√™ncias dispon√≠veis em bases de dados p√ļblicas. Novas sequ√™ncias de flaviv√≠rus espec√≠ficos de insetos ditos "cl√°ssicos" (cISF) foram detetadas em pools de mosquitos das tr√™s regi√Ķes geogr√°ficas, e diferentes sub-linhagens de cISF foram caracterizadas. A sua an√°lise filodin√Ęmica sugeriu que a dispers√£o de cISF no espa√ßo e no tempo dever√° ser recente e bastante din√Ęmica. Por outro lado, embora dados insuficientes n√£o tenham permitido uma an√°lise filodin√Ęmica completa com base em sequ√™ncias de mesoniv√≠rus, foi realizada uma extensa revis√£o taxon√≥mica, que incluiu a an√°lise de sequ√™ncias semelhantes a mesoniv√≠rus (meson-like viruses) recentemente detetadas em outros organismos que n√£o mosquitos. Por fim, tamb√©m procur√°mos analisar entre os parvov√≠rus de invertebrados aqueles que t√™m sido inclu√≠dos no g√©nero Brevihamaparvovirus, cuja distribui√ß√£o at√© ao momento parece ser restrita a algumas esp√©cies de mosquitos. Os seus genomas parecem evoluir sob forte sele√ß√£o negativa e tamb√©m s√£o caracterizados por baixa entropia, tal como foi igualmente observado para flaviv√≠rus e mesoniv√≠rus. Tamb√©m realiz√°mos uma revis√£o taxon√≥mica do t√°xon (o primeiro para brevihamaparvov√≠rus) e efetu√°mos a sua primeira reconstru√ß√£o filodin√Ęmica.Arboviruses are responsible for impactful viral diseases and are transmitted to humans and other animals by insect and other arthropod vectors. Among the latter, mosquitoes pose as one of the most important hematophagous vectors known to carry pathogenic arboviruses for humans, like dengue and Zika. For a long while, virus research was driven by the negative impact viruses impose on human/animal/plant health, but recent developments in next-generation sequencing and bioinformatics have allowed for improvements on virus discovery strategies. In turn, these have led to an increase in the number of peculiar viruses detected in viral screening-based studies, some of which display restricted replication in vertebrate cells. These viruses, designated insect-specific viruses, are thought to have none-to-low impact on animal health and have endured in the shadow of pathogenic arboviruses. However, in the last decades they have become the focus of our attention, not only due to their extensive diversity and unusual host-restriction strategies, but also because of their potential to interfere with the replication of arboviruses. Insect-specific viruses have since been discovered in multiple virus families, with mosquito-specific viruses especially associated with the Flaviviridae, Mesoniviridae and Parvoviridae families. In this project we sought to detect and analyze new insect-specific virus sequences from these three viral families in mosquitoes collected in Portugal, Angola and Mozambique. Genetic diversity, phylogenetic reconstruction and phylodynamic assessments were then executed, using both new generated sequences and sequences available in public databases. New classical insect-specific flavivirus (cISF) sequences were detected in mosquito pools from these three geographic regions, and different sub-lineages inside the cISF cluster were characterized. Phylodynamics analyses suggested that cISF dispersion over space and time could be recent and quite dynamic. On the other hand, while insufficient data did not allow for a full phylodynamic analysis based on mesonivirus sequences, an extensive taxonomy revision was performed, that also included the analysis of sequences similar to mesoniviruses (meson-like viruses) recently detected in organisms other than mosquitoes. Finally, we also sought to analyze among the parvoviruses of invertebrates those included in the Brevihamaparvovirus genus, that have been restricted (so far) to a few mosquito species. Their genomes seem to evolve under strong purifying selection and are also characterized by low entropy, as also observed for flaviviruses and mesoniviruses. We also performed a taxonomic revision of the taxon (the first ever for brevihamaparvoviruses), and attempted their first ever phylodynamic reconstruction
    • ‚Ķ
    corecore