287 research outputs found
Morita Equivalence, Picard Groupoids and Noncommutative Field Theories
In this article we review recent developments on Morita equivalence of star
products and their Picard groups. We point out the relations between
noncommutative field theories and deformed vector bundles which give the Morita
equivalence bimodules.Comment: Latex2e, 10 pages. Conference Proceeding for the Sendai Meeting 2002.
Some typos fixe
Deformation Quantization of a Certain Type of Open Systems
We give an approach to open quantum systems based on formal deformation
quantization. It is shown that classical open systems of a certain type can be
systematically quantized into quantum open systems preserving the complete
positivity of the open time evolution. The usual example of linearly coupled
harmonic oscillators is discussed.Comment: Major update. Improved main statements. 21 page
Homogeneous spaces of Dirac groupoids
A Poisson structure on a homogeneous space of a Poisson groupoid is homogeneous if the action of the Lie groupoid on the homogeneous space is compatible with the Poisson structures. According to a result of Liu, Weinstein and Xu, Poisson homogeneous spaces of a Poisson groupoid are in correspondence with suitable Dirac structures in the Courant algebroid defined by the Lie bialgebroid of the Poisson groupoid. We show that this correspondence result fits into a more natural context: the one of Dirac groupoids, which are objects generalizing Poisson groupoids and multiplicative closed 2-forms on groupoids
Utilização de técnica de geoprocessamento no diagnóstico territorial dos sistemas agrícolas da citricultura familiar sergipana.
A realização de diagnóstico territorial dos sistemas agrícolas de produção é etapa essencial da análise de sua evolução e sustentabilidade. Nesse trabalho realizou-se a localização de propriedades representativas da citricultura familiar em Sergipe utilizando o Sistema de Posicionamento Global (GPS)
Integration of Dirac-Jacobi structures
We study precontact groupoids whose infinitesimal counterparts are
Dirac-Jacobi structures. These geometric objects generalize contact groupoids.
We also explain the relationship between precontact groupoids and homogeneous
presymplectic groupoids. Finally, we present some examples of precontact
groupoids.Comment: 10 pages. Brief changes in the introduction. References update
Relative and Absolute Risk to Guide the Management of Pulse Pressure, an Age-Related Cardiovascular Risk Factor
BACKGROUND Pulse pressure (PP) reflects the age-related stiffening of the central arteries, but no study addressed the management of the PP-related risk over the human lifespan.
METHODS In 4663 young (18-49 years) and 7185 older adults (≥50 years), brachial PP was recorded over 24-hour. Total mortality and all major cardiovascular events combined (MACE) were co-primary endpoints. Cardiovascular death, coronary events and stroke were secondary endpoints.
RESULTS In young adults (median follow-up, 14.1 years; mean PP, 45.1 mmHg), greater PP was not associated with absolute risk; the endpoint rates were ≤2.01 per 1000 person-years. The adjusted hazard ratios expressed per 10-mmHg PP increments were less than unity (P≤0.027) for MACE (0.67; 95% CI, 0.47-0.96) and cardiovascular death (0.33; 95% CI, 0.11-0.75). In older adults (median follow-up, 13.1 years; mean PP, 52.7 mmHg), the endpoint rates, expressing absolute risk, ranged from 22.5 to 45.4 per 1000 person-years and the adjusted hazard ratios, reflecting relative risk, from 1.09 to 1.54 (P3-fold from age 55 to 75 years, whereas absolute risk rose by a factor 3.
CONCLUSIONS From 50 years onwards, the PP-related relative risk decreases, whereas absolute risk increases. From a lifecourse perspective, young adulthood provides a window of opportunity to manage risk factors and prevent target organ damage as forerunner of premature death and MACE. In older adults, treatment should address absolute risk, thereby extending life in years and qualit
Star products made (somewhat) easier
We develop an approach to the deformation quantization on the real plane with
an arbitrary Poisson structure which based on Weyl symmetrically ordered
operator products. By using a polydifferential representation for deformed
coordinates we are able to formulate a simple and effective
iterative procedure which allowed us to calculate the fourth order star product
(and may be extended to the fifth order at the expense of tedious but otherwise
straightforward calculations). Modulo some cohomology issues which we do not
consider here, the method gives an explicit and physics-friendly description of
the star products.Comment: 20 pages, v2, v3: comments and references adde
Generalized Kaehler Potentials from Supergravity
We consider supersymmetric N=2 solutions with non-vanishing NS three-form.
Building on worldsheet results, we reduce the problem to a single generalized
Monge-Ampere equation on the generalized Kaehler potential K recently
interpreted geometrically by Lindstrom, Rocek, Von Unge and Zabzine. One input
in the procedure is a holomorphic function w that can be thought of as the
effective superpotential for a D3 brane probe. The procedure is hence likely to
be useful for finding gravity duals to field theories with non-vanishing
abelian superpotential, such as Leigh-Strassler theories. We indeed show that a
purely NS precursor of the Lunin-Maldacena dual to the beta-deformed N=4
super-Yang-Mills falls in our class.Comment: "38 pages. v3: improved exposition and minor mistakes corrected in
sec. 4
Resistant Hypertension Trials and Tribulations
Introduction
Our case concerns a 62-year-old white woman who was referred by her general practitioner in 2012 with a long-standing history of difficult to control blood pressure (BP). She had significant past medical history including an excised meningioma and an implantable cardiac defibrillator for a single episode of polymorphic ventricular tachycardia during general anesthesia. She also had a possible diagnosis of epilepsy and tablet-controlled type-2 diabetes mellitus.
On referral to our clinic she was on 5 antihypertensive medications including enalapril 40 mg daily, bisoprolol 10 mg daily, lercanidipine 10 mg daily, losartan 50 mg daily, and indapamide 2.5 mg once daily. She was also on metformin and sodium valproate.
In clinic, she appeared well. She complained of occasional headaches but had no other symptom of note. She had no significant family history of high BP. On examination, she had a body mass index in the normal range and after repeated measures, her clinic BP was found to be 195/110 mm Hg. There was very little else to find on examination, including no murmurs or renal bruits. On fundoscopy, she had grade 2 hypertensive retinopathy.
Baseline investigations did not reveal anything untoward. She had a normal blood count, renal function, and electrolytes. On urinalysis, she had mild proteinuria, with a urine protein-creatinine ratio of 17 (laboratory reference value 0–13 mg/mmol). Her ECG showed sinus rhythm with a normal rate, axis, and voltage. Her echocardiogram did not show any evidence of left ventricular hypertrophy, left ventricular ejection fraction was 58%, and she had evidence of mild diastolic dysfunction.
Ambulatory BP monitoring (ABPM) was performed and her mean 24-hour BP was 190/105 mm Hg. The range was 118/67 to 227/127 mm Hg, with >90% of readings >140/90 mm Hg. So, here, we have a patient with a diagnosis of resistant hypertension according to the definition in the European guidelines
- …