4,982 research outputs found
The first coefficients of the asymptotic expansion of the Bergman kernel of the spin^c Dirac operator
We establish the existence of the asymptotic expansion of the Bergman kernel
associated to the spin-c Dirac operators acting on high tensor powers of line
bundles with non-degenerate mixed curvature (negative and positive eigenvalues)
by extending the paper " On the asymptotic expansion of Bergman kernel "
(math.DG/0404494) of Dai-Liu-Ma. We compute the second coefficient b_1 in the
asymptotic expansion using the method of our paper "Generalized Bergman kernels
on symplectic manifolds" (math.DG/0411559).Comment: 21 pages, to appear in Internat. J. Math. Precisions added in the
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Search for decay of Eu to the first excited level of Pm using underground -ray spectrometry
The alpha decay of Eu to the first excited level of Pm
(, keV) was searched for at the HADES underground
laboratory ( m w.e.). A sample of high purity europium oxide with
mass of 303 g and a natural isotopic composition has been measured over 2232.8
h with a high energy resolution ultra-low background n-type semi-planar HPGe
detector (40 cm) with sub-micron deadlayer. The new improved half-life
limit has been set as yr at 68% C.L.
Possibilities to improve the sensitivity of the experiment, which is already
near the theoretical predictions, are discussed. New half-life limit for
decay of Eu is also set as
yr.Comment: 11 pages, 5 figures, 2 tables, 18 reference
An analogue of oka’s theorem for weakly normal complex spaces
Two well known results concerning normal complex spaces are the following. First, the singular set of a normal complex space has codimension at least two. Second, this property characterizes normality for complex spaces which are local complete intersections. This second result is a theorem of Abhyankar [1] which generalizes Oka’s theorem. The purpose of this paper is to prove analogues of these facts for the class of weakly normal complex spaces, which were introduced by Andreotti-Norguet [3] in a study of the space of cycles on an algebraic variety. A weakly normal complex space can have singularities in codimension one, but it will be shown that an obvious class of such singularities is generic. © 1977 Pacific Journal of Mathematics. All rights reserved
A simplified formula to estimate the load history due to ballistic impacts with bullet splash. Development and validation for finite element simulation of 9x21mm full metal jacket bullets
An original simplified formula is proposed to estimate the load history caused by ballistic impacts characterized by the so-called bullet splash phenomenon, consisting in the complete bullet fragmentation with no penetration of the target. The formula is based on the progressive momentum variation of the mass of the bullet impacting on a planar plate normal to the impact direction. The method aims at creating a simplified approach to assess the response of structures by means of explicit finite element simulations without the need of modelling the interaction between impactor and target. The results demonstrate that the proposed method can be used to estimate the forces generated by bullet-splash phenomena of 9x21mm full metal jacket bullets and effectively applied to finite element simulations allowing significant reductions in computational cost
Data from a multidisciplinary poll of 178 expert physicians on the usage of non-vitamin K Oral Anticoagulants in patients with atrial fibrillation and venous thromboembolism
This data article contains data from a multidisciplinary questionnaires filled in by 178 expert physicians on the usage of non-vitamin K Oral Anticoagulants in patients with atrial fibrillation (AF) and for the treatment of patients with venous thromboembolism (VTE). The questionnaire consists of 9 statements of clinical complex AF and VTE cases and informative campaign on antithrombotic therapy for stroke prevention in AF. The data are potentially valuable for the scientific community, showing the doubts of different specialists (Internists, Pneumologists, Geriatricians, Cardiologists and Neurologists) with a large experience in prescribing oral anticoagulation in difficult AF and VTE cases (see full list of participants provided). The data obtained in some particular clinical cases such as CHA2DS2-VASc=1, comorbid coronary artery disease, frailty, advanced age, risk of falling and prior haemorrhagic stroke, can be compared with indications from published guidelines and recommendations for future insight and to be considered as a benchmark for future trials in the area or oral anticoagulation for AF and VTE.The data concerning informative campaign on antithrombotic therapy for stroke prevention showed the expert panel agreement on the inclusion of self monitoring of heart rhythm by pulse taking in subjects older than 64 years of age (81% agreement, item 3); knowledge that the risk of stroke associated with AF is almost twice the risk associated with hypertension (95% agreement, item 4); knowledge that the CHA2DS2-VASc score exerts a higher influence on stroke risk compared to AF duration (92% agreement, item 5); knowledge that stroke prevention in AF with a NOAC is more effective, does not cause any higher bleeding risk, and is equally simple compared to aspirin treatment (91% agreement, item 6).Data on strategies to optimise appropriate prescription of antithrombotic therapy showed agreement on the utility of short television advertisements about the risks of stroke associated with AF (79% agreement, item 8), on a campaign encouraging regular control of cardiac rhythm by pulse taking (77% agreement, item 1), on a campaign reporting the advantages of anticoagulation over no antithrombotic therapy (98% agreement, item 2) or of NOACs over aspirin (96% agreement, item 3) or on the practical use of NOAC (93% agreement, item 6) or on stroke and bleeding risk scores (87% agreement, item 7). See Colonna et al. (2017) [1] for further interpretation and discussion
A collimation system for ELI-NP Gamma Beam System - design and simulation of performance
The purpose of this study was to evaluate the performance and refine the design of the collimation system for the gamma radiation source (GBS) currently being realised at ELI-NP facility. The gamma beam, produced by inverse Compton scattering, will provide a tunable average energy in the range between 0.2 and 20 MeV, an energy bandwidth 0.5% and a flux of about 108 photons/s. As a result of the inverse Compton interaction, the energy of the emitted radiation is related to the emission angle, it is maximum in the backscattering direction and decreases as the angle increase [1,2]. Therefore, the required energy bandwidth can be obtained only by developing a specific collimation system of the gamma beam, i.e. filtering out the radiation emitted at larger angles. The angular acceptance of the collimation for ELI-NP-GBS must be continuously adjustable in a range from about 700 to 60 μrad, to obtain the required parameters in the entire energy range. The solution identified is a stack of adjustable slits, arranged with a relative rotation around the beam axis to obtain an hole with an approximately circular shape. In this contribution, the final collimation design and its performance evaluated by carrying out a series of detailed Geant4 simulations both of the high-energy and the low-energy beamline are presented
A mutant of phosphomannomutase1 retains full enzymatic activity, but is not activated by IMP : possible implications for the disease PMM2-CDG
The most frequent disorder of glycosylation, PMM2-CDG, is caused by a deficiency of phosphomannomutase activity. In humans two paralogous enzymes exist, both of them require mannose 1,6-bis-phosphate or glucose 1,6-bis-phosphate as activators, but only phospho-mannomutase1 hydrolyzes bis-phosphate hexoses. Mutations in the gene encoding phosphomannomutase2 are responsible for PMM2-CDG. Although not directly causative of the disease, the role of the paralogous enzyme in the disease should be clarified. Phosphomannomutase1 could have a beneficial effect, contributing to mannose 6-phosphate isomerization, or a detrimental effect, hydrolyzing the bis-phosphate hexose activator. A pivotal role in regulating mannose-1phosphate production and ultimately protein glycosylation might be played by inosine monophosphate that enhances the phosphatase activity of phosphomannomutase1. In this paper we analyzed human phosphomannomutases by conventional enzymatic assays as well as by novel techniques such as 31P-NMR and thermal shift assay. We characterized a triple mutant of phospomannomutase1 that retains mutase and phosphatase activity, but is unable to bind inosine monophosphate
Relação entre a comercialização e a eficiência de acaricidas no Estado de Mato Grosso do Sul.
O carrapato-do-boi foi introduzido no Brasil em função da utilização de bovinos nas expedições exploradoras dos séculos passados representando hoje um sério problema na pecuária nacional. Os prejuízos estimados giram em torno de US$ 2 bilhões anuais e são provocados pelo estresse, perda de peso, danos no couro, transmissão de patógenos, além de gastos relacionados com o controle do parasita. O controle químico é a principal forma de tratamento, cujo uso indiscriminado favorece o surgimento de resistência. Neste trabalho, teve-se por objetivo relacionar a comercialização de produtos acaricidas com a sua eficiência no controle do carrapato-do-boi no Estado de Mato Grosso do Sul. As informações referentes à comercialização dos acaricidas foram obtidas no período de setembro a dezembro de 2010,por meio de entrevista oral com os funcionários responsáveis pelo setor de vendas das lojas agropecuárias da cidade de Campo Grande. O diagnóstico da resistência foi feito com o teste TIA na Embrapa Gado de Corte pelo Programa de Controle do Carrapato de 30 propriedades rurais. Foram testados 11 carrapaticidas nas suas formulações comerciais, representados por cipermetrina (5%) + diclorvós (45%); cipermetrina (20%) + clorpirifós (50%); cipermetrina (15%); diclorvós (60%) + clorpirifós (20%); amitraz (12,5 %); deltametrina (2,5%); diclorvós (60%) + clorfenvinfós (20%); cipermetrina (8%) + ethion (60%); clorpirifós (25%) + cipermetrina (15%) + butóxido de piperonila (15%) + citronelal (1%); e clorpirifós (25%) + cipermetrina (15%) + citronelal (1%). Os piretroides representam 60% dos produtos mais vendidos, seguidos pelos organofosforados (37,14%). Dos onze produtos testados, dois não alcançaram a eficiência recomendada pelo MAPA, acima de 95%, em nenhuma das propriedades testadas sendo que cipermetrina (15%) apresentou eficiência média de 32,22% e cipermetrina (8%) + ethion (60%), eficiência média de 54,38%. Os produtos com melhores resultados foram clorpirifós (25%) + cipermetrina (15%) + butóxido de piperonila (15%) + citronelal (1%) e diclorvós (60 %) + clorfenvinfós (20%) com eficiência média de 99,34% e 97,48%, respectivamente. Os dados sugerem uma relação direta entre produtos presentes no mercado versus resistência, enfatizando a necessidade do monitoramento dos mecanismos da resistência associado à implementação de um programa de controle estratégico de carrapatos, levando ao manejo adequado de acaricidas e uma política de fiscalização atuante por parte dos órgãos competentes com relação aos produtos químicos disponíveis no mercado para o controle do carrapato-do-boi.bitstream/item/48613/1/BP28.pd
Tagetes minuta - uma nova alternativa no controle fitoterápico de carrapatos.
Obrigatoriamente os carrapatos são parasitas hematófagos (FREIRE, 1972) da maioria dos animais vertebrados, podendo transmitir uma variedade de agentes patogênicos (ESTRADA-PENA; JONGEJAN, 1999). Depois dos mosquitos os carrapatos são considerados o primeiro grupo de artrópodes ectoparasitos a transmitirem agentes patogênicos aos seres humanos, e ocupam o primeiro lugar na transmissão de agentes causadores de doenças aos animais (JONGEJAN; UILENBERG, 2004; OGRZEWALSKA, 2009). Pertencem ao filo Arthropoda, classe Arachnida, ordem Acari e subordem Ixodida e apresentam uma ampla distribuição geográfica.bitstream/item/109847/1/DOC207.pd
Dynamical compressibility of dense granular shear flows
It has been conjectured by Bagnold [1] that an assembly of hard
non-deformable spheres could behave as a compressible medium when slowly
sheared, as the average density of such a system effectively depends on the
confining pressure. Here we use discrete element simulations to show the
existence of transverse and sagittal waves associated to this dynamical
compressibility. For this purpose, we study the resonance of these waves in a
linear Couette cell and compare the results with those predicted from a
continuum local constitutive relation
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