3,847 research outputs found

    Hamiltonian embedding of the massive noncommutative U(1) theory

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    We show that the massive noncommutative U(1) can be embedded in a gauge theory by using the BFFT Hamiltonian formalism. By virtue of the peculiar non-Abelian algebraic structure of the noncommutative massive U(1) theory, several specific identities involving Moyal commutators had to be used in order to make the embedding possible. This leads to an infinite number of steps in the iterative process of obtaining first-class constraints. We also shown that the involutive Hamiltonian can be constructed.Comment: 8 pages, Revtex (multicol

    Portuguese crypto-Jews: The genetic heritage of a complex history

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    The first documents mentioning Jewish people in Iberia are from the Visigothic period. It was also in this period that the first documented anti-Judaic persecution took place. Other episodes of persecution would happen again and again during the long troubled history of the Jewish people in Iberia and culminated with the Decrees of Expulsion and the establishment of the Inquisition: some Jews converted to Catholicism while others resisted and were forcedly baptized, becoming the first Iberian Crypto-Jews. In the 18th century the official discrimination and persecution carried out by the Inquisition ended and several Jewish communities emerged in Portugal. From a populational genetics point of view, the worldwide Diaspora of contemporary Jewish communities has been intensely studied. Nevertheless, very little information is available concerning Sephardic and Iberian Crypto-Jewish descendants. Data from the Iberian Peninsula, the original geographic source of Sephardic Jews, is limited to two populations in Portugal, Belmonte, and Bragança district, and the Chueta community from Mallorca. Belmonte was the first Jewish community studied for uniparental markers. The construction of a reference model for the history of the Portuguese Jewish communities, in which the genetic and classical historical data interplay dynamically, is still ongoing. Recently an enlarged sample covering a wide region in the Northeast Portugal was undertaken, allowing the genetic profiling of male and female lineages. A Jewish specific shared female lineage (HV0b) was detected between the community of Belmonte and Bragança. In contrast to what was previously described as a hallmark of the Portuguese Jews, an unexpectedly high polymorphism of lineages was found in Bragança, showing a surprising resistance to the erosion of genetic diversity typical of small-sized isolate populations, as well as signs of admixture with the Portuguese host population

    Machine learning risk prediction of mortality for patients undergoing surgery with perioperative SARS-CoV-2: the COVIDSurg mortality score.

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    To support the global restart of elective surgery, data from an international prospective cohort study of 8492 patients (69 countries) was analysed using artificial intelligence (machine learning techniques) to develop a predictive score for mortality in surgical patients with SARS-CoV-2. We found that patient rather than operation factors were the best predictors and used these to create the COVIDsurg Mortality Score (https://covidsurgrisk.app). Our data demonstrates that it is safe to restart a wide range of surgical services for selected patients

    Assessment of nutrient returns in a tropical dry forest after clear-cut without burning.

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    Tropical dry forests (TDFs) are being deforested at unprecedented rates. The slash/burn/ agriculture/fallow-extensive livestock sequence causes significant nutrient losses and soil degradation. Our aim is to assess nutrient inputs and outputs in a TDF area under an alternative management system, for exclusive wood production. The study involved clear-cutting a preserved caatinga TDF site without burning, quantifying nutrients exported in firewood/ timber and nutrients returned to the soil from the litter layer plus the slash debris, left to decompose unburned on the soil surface. Before clear-cut, the litter layer on the forest floor contained 6.1 t ha of dry matter (DM). After clear-cut, the aboveground biomass was 61.9 t DM ha-1 (consisting of 21.5 t DM ha-1 of commercial wood and 40.4 t DM ha-1 of clear-cut debris that did not include the underlying litter layer). The litter layer was composed of fine and coarse litter, with turnovers of 0.86 and 0.31 year-1, respectively, separately measured in uncut control plots during two rainy seasons (Dec-2007/June-2008 and Dec-2008/ June-2009). In a single season, its decomposition returned to the soil 48.4, 1.16 and 12.3 kg ha-1 of N, P and K. The clear-cut debris was mainly composed of branches, 33.4 t ha-1, bromeliads, 5.63 t ha-1 and green leaves, 1.32 t ha-1. In-situ decomposition rates for branches and bromeliads were 0.24 and 1.47 year-1, respectively. After two rainy seasons the clear-cut debris released 206, 6.5 and 106 kg ha-1 of N, P and K respectively. This input plus that of the underlying litter layer exceeded exports in the commercial wood, and replenished a soil nutrient stock (0?30 cm) of approximately the same magnitude

    Índices de emissão de ramos em pereiras.

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    A elaboração de escalas de emissão de ramos em pereiras objetiva classificar os genótipos quanto a seu hábito de crescimento, as quis serão úteis para compor o índice de vigor de plantas e para a seleção de genitores em programas de melhoramento genético. Para isso, foram desenvolvidas duas escalas: a primeira, para avaliar a quantidade de emissão de ramos secundários, ou seja, os ramos originados do tronco principal da planta, composta por três classes e com notas variando entre 1 e 5, contendo desenhos e exemplos de genótipos; a segunda, para avaliar o tipo e a quantidade de ramos terciários e quaternários emitidos a partir dos ramos secundários, sendo ela composta também por três classes e notas variando de 1 a 5. Utilizando as duas tabelas, foram avaliadas duas (em alguns casos somente uma) plantas/genótipo do Banco de Germoplasma de Pereira existente na Estação Experimental de Caçador, em Caçador, SC, no ano agrícola 2012/13. As plantas ficaram sem poda e condução durante 2 anos. Exemplos de genótipos com menor emissão de ramos secundários foram os cvs. Kousui, Kikusui, Nijisseiki, Beurre d?Anjou e Doyenne du Comice; e com maior emissão os cvs. Le Conte e Md. Siebold. Quanto à menor emissão de ramos terciários e quaternários, destacaram-se os cvs. Rugosa e Md. Siebold; e com maior emissão os cvs. Feliz e Choujuurou. As escalas foram eficientes na separação dos genótipos

    Classes de vigor de plantas de genótipos de pereira.

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    O índice de vigor de pereiras pode ser utilizado como referência em trabalhos de melhoramento genético para a seleção de genitores e também como indicativo de manejo de plantas em pomares comerciais. Para isso, foi gerado um índice de vigor utilizando informações de emissão de ramos secundários (originados do tronco principal da planta), de ramos terciários e quaternários (gerados respectivamente dos ramos secundários e terciários), além da medida da altura da planta

    Myocardial bridging: retrospective analysis and scintigraphic testing of patients with no angiographically significant atherosclerotic coronary disease.

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    Rev Port Cardiol. 2006 Apr;25(4):397-406. Myocardial bridging: retrospective analysis and scintigraphic testing of patients with no angiographically significant atherosclerotic coronary disease. [Article in English, Portuguese] Luz A, Silveira J, Palma P, Carvalho HC, Albuquerque A, Amorim I, Gomes L. SourceServiço de Cardiologia, Hospital Geral de Santo António, Porto, Portugal. [email protected] Abstract INTRODUCTION AND OBJECTIVE: The clinical relevance of myocardial bridging (MB) is a matter of debate. The objective of this work was to examine its prevalence, clinical presentation, prognosis, and functional features on scintigraphy in a group of patients with no significant atherosclerotic coronary disease. METHODS: We retrospectively examined 7039 consecutive cardiac angiograms performed between January 1994 and December 2004, selecting cases in which MB was not accompanied by significant coronary disease (defined as luminal stenosis > 50%), valvular heart disease or cardiomyopathy. Patient characteristics such as age, gender, vascular risk factors and clinical presentation were recorded. We then contacted these patients by telephone to determine cardiovascular events since diagnosis (hospitalization, infarction, death) or symptoms of angina, and to invite them for myocardial perfusion scintigraphy (MPS) with stress testing. RESULTS: The prevalence of MB was 0.97% (68 patients). The study population without significant coronary disease, valvular heart disease or cardiomyopathy was composed of 31 subjects, mean age 51.45 +/- 13.77 years, 94% (29 patients) male. Clinical presentations were: non-ST elevation acute coronary syndromes with or without biomarkers of necrosis 34% (14 patients), stable angina 23% (7 patients), atypical chest pain 16% (5 patients), ST-elevation myocardial infarction 13% (4 patients), other 3% (1 patient). Left ventricular function was normal in all patients, and angiography showed MB of the left anterior descending artery, 63% (19 patients) in the mid portion, and 33% (12 patients) in the distal portion. All subjects were treated medically. We were able to contact 24 (77%) of the 31 patients, all of whom underwent MPS; mean time since angiography was 61.25 months, with no cardiovascular events (hospitalization, infarction, death) or symptomatic angina. MPS only identified three patients with findings consistent with anterior wall ischemia. CONCLUSIONS: In this series, 58% of the patients with MB and no significant atherosclerotic coronary disease presented with acute coronary syndromes. In all the subjects contacted, the prognosis had been good during the time since diagnosis. In the majority of them, no signs of ischemia were detected on MPS. PMID: 16869205 [PubMed - indexed for MEDLINE

    Environmental hazards of nanopesticides to non-target soil species - commercial nanoformulation versus its active substance (Karate Zeon® and lambda-cyhalothrin)

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    Nanopesticides (Npes) carry the potential of increased efficacy while reducing application rates, hence increasing agricultural productivity in a more sustainable way. However, given its novelty, the environmental risk assessment of these advanced materials is mostly absent. In the present study we investigated the ecotoxicity of a commercial insecticide, with reported nanofeatures, Karate Zeon®, and compared it to its active substance lambda-cyhalothrin. It is hypothesised that the use of the nanopesticide Karate Zeon® poses lower risk to enchytraeids than its active substance. The standard non-target soil invertebrate Enchytraeus crypticus was used, and exposure was done in LUFA 2.2 soil in 4 tests (endpoints: days): avoidance test [avoidance behaviour: 2 days], OECD standard reproduction test [survival, reproduction plus adults' size: 28 days] and its extension [total number organisms: 56 days], and Full Life Cycle (FLC) test [hatching and juveniles' size: 13 days; survival, reproduction and adults' size: 46 days]. Results showed that enchytraeids did not avoid Karate Zeon® nor its active substance lambda-cyhalothrin, which could be due to neurotoxicity. There was no indication of increased toxicity with prolonged exposure (46, 56d) compared to the standard (28d) for neither of the materials, being overall equally toxic in terms of hatching, survival, and reproduction. The FLCt results indicated that the juvenile stage was the most sensitive, resulting in higher toxicity for the adult animals when exposed from the cocoon stage. Although toxicity was similar between Karate Zeon and lambda-cyhalothrin, different patterns of uptake and elimination cannot be excluded. The benefits of using Karate Zeon will rely on reduced application rates.publishe
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