333 research outputs found
Rectifiability and upper Minkowski bounds for singularities of harmonic Q-valued maps
In this article we prove that the singular set of Dirichlet-minimizing Q-valued functions is countably .m2/-rectifiable and we give upper bounds for the .m2/-dimensional Minkowski content of the set of singular points with multiplicity Q
CaracterizaciĂłn del rĂ©gimen agroclimático de heladas para la provincia de Santa Fe durante el perĂodo 1979 - 2004
p.53-62El conocimiento del rĂ©gimen de las temperaturas consideradas limitantes para los cultivos, es indispensable para la toma de decisiones respecto al calendario agrĂcola de una regiĂłn. Con datos de temperatura mĂnima diaria de seis localidades de la provincia de Santa Fe, donde existen estaciones del SMN (perĂodo 1979-2004) se caracterizĂł el rĂ©gimen agroclimático de heladas meteorolĂłgicas y agronĂłmicas. Se determinaron las fechas medias de primeras y Ăşltimas heladas, las respectivas fechas extremas, el perĂodo libre de heladas, y los Ăndices de peligrosidad. Por medio de estadĂsticos simples se analizĂł las frecuencias de dĂas con heladas mensuales y anuales. Las fechas medias de primeras y Ăşltimas heladas meteorolĂłgicas están comprendidas entre 27 de junio y el 2 de septiembre. El perĂodo medio con heladas meteorolĂłgicas en ningĂşn caso supera los 90 dĂas. Las heladas agronĂłmicas comienzan en mayo y terminan en septiembre. El perĂodo medio con heladas agronĂłmicas aumenta hasta 150 dĂas en el SE de la provincia
Influence of LV Neutral Grounding on Global Earthing Systems
International Standards define a Global Earthing System as an earthing net created interconnecting local Earthing Systems (generally through the shield of MV cables and/or bare buried conductors). In Italy the Regulatory Authority for Electricity and Gas requires Distributors to guarantee the electrical continuity of LV neutral conductor. This requirement has led to the standard practice of realizing “reinforcement groundings” along the LV neutral conductor path and at users’ delivery cabinet. Moreover, in urban high load scenarios (prime candidates to be part of a Global Earthing System), it is common that LV distribution scheme creates, trough neutral conductors, an effective connection between grounding systems of MV/LV substations, modifying Global Earthing System consistency. Aim of this paper is to evaluate the effect, in terms of electrical safety, of the above mentioned LV neutral distribution scheme when an MV-side fault to ground occurs. At this purpose simulations are carried out on a realistic urban test case and suitable evaluation indexes are proposed
A Practical Method to Test the Safety of HV/MV Substation Grounding System
The adequacy of a Grounding System (GS) to the safety conditions has to be periodically tested by measurements. The test methods and techniques used to verify the electrical characteristics of the GS include the measurements of step and touch voltages. The goal of the test is to verify that touch voltage and step voltage remain below a safe value in all the zones of the installation. The measurements can present some operational difficulties. The purpose of this paper is to present the procedure, step-by-step, of a practical method of measuring touch/step voltages in grounding systems located in urban or industrial areas with reduced accessibility. The suggested method uses auxiliary current electrodes located at short distances. This paper demonstrates by test measurements done in a real case that the method provides conservative results
Combined characterization of a pituitary adenoma and a subcutaneous lipoma in a MEN1 patient with a whole gene deletion
Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant hereditary disorder associated with mutations of the MEN1 gene, which is characterized by combined tumors of the parathyroid glands, pancreatic islet cells, and the anterior pituitary. A significant number of patients with the clinical features of MEN1, however, do not show MEN1 mutations upon direct sequencing. We describe a young woman who fulfilled the clinical and biochemical criteria for MEN1 syndrome, but DNA sequencing did not indicate any MEN1 mutations. She developed a prolactin-secreting pituitary macroadenoma, primary hyperparathyroidism with parathyroid hyperplasia, pancreatic lesions, and two subcutaneous lipomas. Array comparative genomic hybridization (aCGH) analysis of peripheral blood DNA revealed a heterozygous germline deletion at 11q13.1 that spanned at least 22.23 kilobases and contained the entire MEN1 gene. Integrated aCGH and cytogenetic analyses of the adenoma and lipoma tissues revealed somatic inactivation of the wild-type MEN1 allele by different routes: the second hit of MEN1 recessive oncogenesis leading to adenoma implied a loss of heterozygosity, whereas a balanced translocation deleting the wild-type MEN1 allele primed the lipoma development. These findings show that aCGH is a valuable means of optimizing genetic testing in MEN1 patients which complements other technologic approaches to elucidating the pathologic mechanisms of MEN1 tumors
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