22,811 research outputs found

    Towards Noncommutative Linking Numbers Via the Seiberg-Witten Map

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    In the present work some geometric and topological implications of noncommutative Wilson loops are explored via the Seiberg-Witten map. In the abelian Chern-Simons theory on a three dimensional manifold, it is shown that the effect of noncommutativity is the appearance of 6n6^n new knots at the nn-th order of the Seiberg-Witten expansion. These knots are trivial homology cycles which are Poincar\'e dual to the high-order Seiberg-Witten potentials. Moreover the linking number of a standard 1-cycle with the Poincar\'e dual of the gauge field is shown to be written as an expansion of the linking number of this 1-cycle with the Poincar\'e dual of the Seiberg-Witten gauge fields. In the process we explicitly compute the noncommutative 'Jones-Witten' invariants up to first order in the noncommutative parameter. Finally in order to exhibit a physical example, we apply these ideas explicitly to the Aharonov-Bohm effect. It is explicitly displayed at first order in the noncommutative parameter, we also show the relation to the noncommutative Landau levels.Comment: 19 pages, 1 figur

    "The Keynesian Roots of Stock-flow Consistent Macroeconomic Models: Peering Over the Edge of the Short Period"

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    This paper argues that institutionally rich stock-flow consistent models—that is, models in which economic agents are identified with the main social categories/institutional sectors of actual capitalist economies, the short period behavior of these agents is thoroughly described, and the "period by period" balance sheet dynamics implied by the latter is consistently modeled—are (1) perfectly compatible with John Maynard Keynes's theoretical views, (2) the ideal tool for rigorous post-Keynesian analyses of the medium run, and (3) therefore crucial to the consolidation of the broad post-Keynesian research program.

    "Revisiting (and Connecting) Marglin-Bhaduri and Minsky--An SFC Look at Financialization and Profit-led Growth"

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    Many heterodox strands of thought share both a concern with the study of different phases or growth regimes in the history of capitalism and the use of formal short-run models as an analytical tool. This text suggests that (1) this strategy is potentially misleading; (2) that the stock-flow consistent (SFC) approach, while providing a general framework that may facilitate the dialogue among those currents, is particularly well suited to all those who think that macroeconomic models may illuminate historical quests; and (3) that the main intuitions may be conveyed through the "benchmark" Post Keynesian SFC model presented by Dos Santos and Zezza (2008), dispensing with the complex computer simulations that are normally employed by SFC authors.

    Got my γδ17 T cells to keep me warm

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    © 2018 Nature America Inc., part of Springer Nature. All rights reservedγδ T cells accumulate with age in adipose tissue and produce the cytokine IL-17, which controls the homeostasis of regulatory T cells and adaptive thermogenesis. Thus, maintenance of core body temperature unexpectedly relies on these adipose tissue–resident γδ17 T cells.info:eu-repo/semantics/publishedVersio

    Charge Discreteness as Model in Charge Migration in a Chain of DNA Molecules under Radiation

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    Charge migration through DNA is a problem to be solved. A numerical wavefront solution for quantum transmission lines with charge discreteness is obtained as model for the charge migration of a chain DNA molecules induced by electromagnetic radiation. The nonlinearity of the system becomes deeply related to charge discreteness. The wavefront velocity depends on the normalized (pseudo) flux variable. Finding the dispersion relation for the normalized flux we show that the condition on the wave-front velocity gives the band-gap conditions for the charge propagation on the system

    The gut microbiota, bile acids and their correlation in primary sclerosing cholangitis associated with inflammatory bowel disease.

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    BACKGROUND: Patients with primary sclerosing cholangitis associated with inflammatory bowel disease (PSC-IBD) have a very high risk of developing colorectal neoplasia. Alterations in the gut microbiota and/or gut bile acids could account for the increase in this risk. However, no studies have yet investigated the net result of cholestasis and a potentially altered bile acid pool interacting with a dysbiotic gut flora in the inflamed colon of PSC-IBD. AIM: The aim of this study was to compare the gut microbiota and stool bile acid profiles, as well as and their correlation in patients with PSC-IBD and inflammatory bowel disease alone. METHODS: Thirty patients with extensive colitis (15 with concomitant primary sclerosing cholangitis) were prospectively recruited and fresh stool samples were collected. The microbiota composition in stool was profiled using bacterial 16S rRNA sequencing. Stool bile acids were assessed by high-performance liquid chromatography tandem mass spectrometry. RESULTS: The total stool bile acid pool was significantly reduced in PSC-IBD. Although no major differences were observed in the individual bile acid species in stool, their overall combination allowed a good separation between PSC-IBD and inflammatory bowel disease. Compared with inflammatory bowel disease alone, PSC-IBD patients demonstrated a different gut microbiota composition with enrichment in Ruminococcus and Fusobacterium genus compared with inflammatory bowel disease. At the operational taxonomic unit level major shifts were observed within the Firmicutes (73%) and Bacteroidetes phyla (17%). Specific microbiota-bile acid correlations were observed in PSC-IBD, where 12% of the operational taxonomic units strongly correlated with stool bile acids, compared with only 0.4% in non-PSC-IBD. CONCLUSIONS: Patients with PSC-IBD had distinct microbiota and microbiota-stool bile acid correlations as compared with inflammatory bowel disease. Whether these changes are associated with, or may predispose to, an increased risk of colorectal neoplasia needs to be further clarified.info:eu-repo/semantics/publishedVersio

    Does she deserve it? The influence of gender and meritocracy in reactions to affirmative action legislation

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    Gender equality is a matter for debate worldwide. In 2018, Portugal enacted legislation (Decree Law no. 62/2017) to balance gender representation on the executive boards of listed and public sector organizations with measures similar to those causing controversies in other countries. Thus, in accordance with previous research, a study took place to examine the attitudes towards the justice of this legislation and the role of merit in these attitudes. This study (n = 129 women and 94 men) deployed an experimentally manipulative type of affirmative action program to consider the role of individual perceptions of the justice of the legislation coupled with the influence of beliefs in meritocracy and participant gender. The results identify how the type of affirmative action impacted on the perceived justice, also influenced by merit, which seems normative and fundamental to evaluating the justice of such legally stipulated provisions. Nonetheless, objectively evaluating candidate merits revealed difficulties in disentangling this process from personality traits.info:eu-repo/semantics/publishedVersio

    Ocorrência da podridão floral dos citros (Coletotrichum acutatum, Simmonds), em diferentes combinações de copa e porta-enxerto.

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    A doença Podridão Floral dos Citros (PFC) ou estrelinha como é conhecida pelos produtores é causada pelo fungo Colletotrichum acutatum, Simmonds que produz lesões de coloração alaranjada ou ferruginosa nos botões florais ou nas pétalas, infectando posteriormente o estilo que se desprende, ficando aderidos aos ramos os receptáculos persistentes da flor. Este trabalho objetivou avaliar a incidência do fungo C. acutatum, Simmonds, em flores de copa de lima ácida Tahiti enxertada sobre cinco diferentes porta-enxertos.PDF. 089_1
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