567 research outputs found

    On the truncation of the harmonic oscillator wavepacket

    Get PDF
    We present an interesting result regarding the implication of truncating the wavepacket of the harmonic oscillator. We show that disregarding the non-significant tails of a function which is the superposition of eigenfunctions of the harmonic oscillator has a remarkable consequence: namely, there exist infinitely many different superpositions giving rise to the same function on the interval. Uniqueness, in the case of a wavepacket, is restored by a postulate of quantum mechanics

    Stabilized Schemes for the Hydrostatic Stokes Equations

    Get PDF
    Some new stable finite element (FE) schemes are presented for the hydrostatic Stokes system or primitive equations of the ocean. It is known that the stability of the mixed formulation ap- proximation for primitive equations requires the well-known Ladyzhenskaya–Babuˇska–Brezzi condi- tion related to the Stokes problem and an extra inf-sup condition relating the pressure and the vertical velocity. The main goal of this paper is to avoid this extra condition by adding a residual stabilizing term to the vertical momentum equation. Then, the stability for Stokes-stable FE combinations is extended to the primitive equations and some error estimates are provided using Taylor–Hood P2 –P1 or miniele- ment (P1 +bubble)–P1 FE approximations, showing the optimal convergence rate in the P2 –P1 case. These results are also extended to the anisotropic (nonhydrostatic) problem. On the other hand, by adding another residual term to the continuity equation, a better approximation of the vertical derivative of pressure is obtained. In this case, stability and error estimates including this better approximation are deduced, where optimal convergence rate is deduced in the (P 1 +bubble)–P1 case. Finally, some numerical experiments are presented supporting previous results

    Almost Perfect Privacy for Additive Gaussian Privacy Filters

    Full text link
    We study the maximal mutual information about a random variable YY (representing non-private information) displayed through an additive Gaussian channel when guaranteeing that only ϵ\epsilon bits of information is leaked about a random variable XX (representing private information) that is correlated with YY. Denoting this quantity by gϵ(X,Y)g_\epsilon(X,Y), we show that for perfect privacy, i.e., ϵ=0\epsilon=0, one has g0(X,Y)=0g_0(X,Y)=0 for any pair of absolutely continuous random variables (X,Y)(X,Y) and then derive a second-order approximation for gϵ(X,Y)g_\epsilon(X,Y) for small ϵ\epsilon. This approximation is shown to be related to the strong data processing inequality for mutual information under suitable conditions on the joint distribution PXYP_{XY}. Next, motivated by an operational interpretation of data privacy, we formulate the privacy-utility tradeoff in the same setup using estimation-theoretic quantities and obtain explicit bounds for this tradeoff when ϵ\epsilon is sufficiently small using the approximation formula derived for gϵ(X,Y)g_\epsilon(X,Y).Comment: 20 pages. To appear in Springer-Verla

    Hiperuricemia y componentes del síndrome metabólico en niños y adolescentes obesos

    Get PDF
    ResumenIntroducciónLa hiperuricemia se ha observado como una alteración metabólica adicional en pacientes adultos obesos, pero es poco conocida su magnitud en pacientes pediátricos.ObjetivosAnalizar la asociación entre ácido úrico sérico (AUS) con magnitud de la obesidad general y visceral y con otras mediciones bioquímicas en niños y adolescentes obesos de Santiago, Chile.Sujetos y métodoEn un estudio transversal se evaluaron 770 niños (edades: 6-15 años) de un colegio público de Santiago, Chile, encontrando 227 obesos (29%) (IMC>2 DE, estándares OMS). Se seleccionaron aleatoriamente 90 niños y aceptaron participar 77, sin otras enfermedades crónicas. Se evaluó: peso, talla, perímetro abdominal, adiposidad visceral con ultrasonografía abdominal y mediciones metabólicas: insulinemia, glucemia (HOMA), lípidos séricos, aspartato aminotransferasa, alanina aminotransferasa (ALT) y AUS.ResultadosLas concentraciones de AUS fueron 0,200±0,065mmol/l. El AUS fue mayor en niños con valores de hiperinsulinismo (ajustado según edad): 0,221±0,075 vs 0,183±0,054mmol/l (p<0,01), sin diferencias según HOMA; las diferencias también se observaron según ALT (>vs<26 U/ml): 0,238±0,070 vs 0,178±0,054mmol/l, p<0,001; la regresión logística controlando por sexo, edad e intensidad de la obesidad mostró solo las ALT asociadas a aumento de AUS. No hubo asociación de mayor AUS con magnitud de IMC, adiposidad visceral o hígado graso.ConclusionesLos niños y adolescentes obesos de Santiago, Chile, tienen una uricemia mayor en asociación a un aumento de la actividad de la enzima ALT e hiperinsulinismo. Se justifica analizar uricemia en el estudio de niños obesos y en su seguimiento.AbstractIntroductionHyperuricaemia has been suggested as an additional metabolic factor in adult obese patients, but it has not been sufficiently studied in paediatric.ObjectivesTo assess the relationship between serum uric acid levels (SUAL) with the level of general and visceral obesity, and other biochemical parameters in children and adolescents of Santiago, Chile.Subjects and methodA cross sectional study was conducted on 770 children and adolescents (ages: 6-15 y.) from a public school in Santiago, Chile, of whom 227 (29%) were obese (BMI>2 SD, WHO growth standards). Ninety subjects were randomly selected and 77 with no other chronic disease (41 males) accepted to participate. Data was collected on weight, stature, abdominal circumference (AC), visceral adiposity using ultrasound, and other biochemical measurements including fasting glucose, insulin, serum lipids, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and SUAL.ResultsThe mean SUAL was 0.200±0.065mmol/L, and was increased in children with hyperinsulinism (adjusted by age: 0.221±0.075 vs 0.183±0.054mmol/L; P<.01), with no significant differences according to HOMA. Differences were also found between children with ALT>or<26 U/mL: 0.238±0.070 vs 0.178±0.054mmol/L, P<.001. The logistic regression showed the increased SUAL was only associated with increased ALT. No significant differences were found in general or visceral adiposity measurements or fatty liver.ConclusionsChildren and adolescents from Santiago, Chile have higher uric acid serum uric acid levels as well as an association with increased ALT and insulin. It is demonstrated in this study that uric acid should be measured in obese children and adolescents, and in their follow up

    Estudio económico de la reutilización de paneles solares en pequeñas instalaciones fotovoltaicas

    Get PDF
    CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: La generación eléctrica a partir de energía solar es limpia, asequible y renovable. Por estos motivos, su aprovechamiento ha sufrido un importante crecimiento en los últimos años y se ha situado como la tercera fuente de generación de energía renovable con más peso en España. Las plantas de generación de energía fotovoltaica son cada vez de mayor tamaño y emplean decenas de miles de módulos en su construcción. Estos módulos sufren, desde el comienzo de su actividad, una degradación continua de sus células que hace disminuir su rendimiento y a menudo son desechados por las grandes empresas aunque no hayan alcanzado el final de su vida útil. Este proyecto estudia de forma técnica y económica la rentabilidad de la reutilización de los paneles fotovoltaicos de Silicio, con el fin reducir la inversión inicial de las instalaciones de autoconsumo fotovoltaico y de ofrecer una segunda vida a los módulos que resultan aptos para continuar produciendo energía.ABSTRACT: Electricity generation from solar energy is clean, affordable and renewable. For this reason, it has grown a lot during the last years and has become the third source of renewable energy generation in Spain. Photovoltaic power generation plants are getting larger and using tens of thousands of modules in their construction. These modules suffer continuous degradation of their, which reduces their performance. For this reason, they are discarded by large companies even though they have not reached the end of their useful life. This project studies in a technical and economic way the reuse of Silicon photovoltaic panels, as they are the most used at present, in order to reduce the initial investment of photovoltaic self-consumption installations and to offer a second life to the modules that are suitable for continuing to produce energy.info:eu-repo/semantics/publishedVersio

    Sistema de inspección mediante imágenes de luminiscencia de módulos solares en funcionamiento

    Get PDF
    CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: Los avances en la detección de defectos en módulos fotovoltaicos por luminiscencia se están viendo demorados por la necesidad que las técnicas de inspección actuales tienen de actuar sobre los contactos eléctricos y retirar los paneles de su estado de funcionamiento. En el presente trabajo se introduce un sistema que vence esta limitación, pudiendo tomar imágenes de luminiscencia sobre módulos solares en funcionamiento. Dicho sistema se pone a prueba mediante la implementación de un primer prototipo funcional, con el que se toman imágenes de un string de células completo para poder compararlas con las obtenidas utilizando las técnicas de inspección actuales, determinando así sus similitudes y diferencias, y corroborando la validez del método propuesto.ABSTRACT: Advances in the detection of defects in photovoltaic modules by luminescence are being delayed by the need that current inspection techniques have to act on the electrical contacts and remove the panels from their operating state. In the present work, a system is introduced that overcomes this limitation, being able to take images of luminescence on solar modules in operation. This system is put to the test by implementing a first functional prototype, with which images are taken of a complete string of cells to be able to compare them with those obtained using current inspection techniques, thus determining their similarities and differences, and corroborating the validity of the proposed method.info:eu-repo/semantics/publishedVersio

    African regional progress and status of the programme to eliminate lymphatic filariasis: 2000–2020

    Get PDF
    To eliminate lymphatic filariasis (LF) by 2020, the World Health Organization (WHO) has launched a campaign against the disease. Since the launch in 2000, significant progress has been made to achieve this ambitious goal. In this article we review the progress and status of the LF programme in Africa through the WHO neglected tropical diseases preventive chemotherapy databank, the Expanded Special Project for Elimination of Neglected Tropical Diseases (ESPEN) portal and other publications. In the African Region there are 35 countries endemic for LF. The Gambia was reclassified as not requiring preventive chemotherapy in 2015, while Togo and Malawi eliminated LF as a public health problem in 2017 and 2020, respectively. Cameroon discontinued mass drug administration (MDA) and transitioned to post-MDA surveillance to validate elimination. The trajectory of coverage continues to accelerate; treatment coverage increased from 0.1% in 2000 to 62.1% in 2018. Geographical coverage has also significantly increased, from 62.7% in 2015 to 78.5% in 2018. In 2019, 23 of 31 countries requiring MDA achieved 100% geographic coverage. Although much remains to be done, morbidity management and disability prevention services have steadily increased in recent years. Vector control interventions conducted by other programmes, particularly malaria vector control, have had a profound effect in stopping transmission in some endemic countries in the region. In conclusion, significant progress has been made in the LF programme in the region while we identify the key remaining challenges in achieving an Africa free of LF

    Steroid regulation: An overlooked aspect of tolerance and chronic rejection in kidney transplantation.

    Get PDF
    Steroid conversion (HSD11B1, HSD11B2, H6PD) and receptor genes (NR3C1, NR3C2) were examined in kidney-transplant recipients with "operational tolerance" and chronic rejection (CR), independently and within the context of 88 tolerance-associated genes. Associations with cellular types were explored. Peripheral whole-blood gene-expression levels (RT-qPCR-based) and cell counts were adjusted for immunosuppressant drug intake. Tolerant (n = 17), stable (n = 190) and CR patients (n = 37) were compared. Healthy controls (n = 14) were used as reference. The anti-inflammatory glucocorticoid receptor (NR3C1) and the cortisol-activating HSD11B1 and H6PD genes were up-regulated in CR and were lowest in tolerant patients. The pro-inflammatory mineralocorticoid gene (NR3C2) was downregulated in stable and CR patients. NR3C1 was associated with neutrophils and NR3C2 with T-cells. Steroid conversion and receptor genes, alone, enabled classification of tolerant patients and were major contributors to gene-expression signatures of both, tolerance and CR, alongside known tolerance-associated genes, revealing a key role of steroid regulation and response in kidney transplantation

    Breast cancer Multiple cycles of dose-intensive chemotherapy with repeated stem cell support as induction treatment in metastatic breast cancer: a feasibility study

    Get PDF
    Summary: The purpose of this trial was to study feasibility and tolerance of a dose-intensive multicyclic alternating induction chemotherapy with repeated stem cell support in a series of 43 metastatic breast cancer patients. ades. Extensive literature reviews by Hryniuk et al 1,2 have found dose intensity to be correlated with response rate and survival. This effect has been considered in the rationale of many clinical trials that attempted to improve long-term survival in metastatic BC by delivering single courses of high-dose chemotherapy (HDC). Despite some promising data derived from phase II trials, results of the randomized studies published thus far have failed to show a sound clinical benefit for single autografts. 8 Multicyclic treatment schemes appear to take advantage of the inherent time-dependant responsiveness of most cancer tissues. Autologous peripheral blood stem cell infusions have been extensively used to support single courses of HDC. Nonetheless, their possible use in programs of multicyclic non-myeloablative dose-intense chemotherapy has been little explored. Materials and methods Women with histologically proven metastatic BC were evaluated for study entry. An ECOG performance status of 0-1, age less than 65 years, and no evidence of cardiac, pulmonary, liver or renal impairment were required. All patients gave written informed consent according to institutional policy before entering the study. Patients presenting with brain metastases, leptomeningeal disease, or bone marrow involvement, as well as patients previousl

    Long-Range Chromosome Organization in E. coli: A Site-Specific System Isolates the Ter Macrodomain

    Get PDF
    The organization of the Escherichia coli chromosome into a ring composed of four macrodomains and two less-structured regions influences the segregation of sister chromatids and the mobility of chromosomal DNA. The structuring of the terminus region (Ter) into a macrodomain relies on the interaction of the protein MatP with a 13-bp target called matS repeated 23 times in the 800-kb-long domain. Here, by using a new method that allows the transposition of any chromosomal segment at a defined position on the genetic map, we reveal a site-specific system that restricts to the Ter region a constraining process that reduces DNA mobility and delays loci segregation. Remarkably, the constraining process is regulated during the cell cycle and occurs only when the Ter MD is associated with the division machinery at mid-cell. The change of DNA properties does not rely on the presence of a trans-acting mechanism but rather involves a cis-effect acting at a long distance from the Ter region. Two specific 12-bp sequences located in the flanking Left and Right macrodomains and a newly identified protein designated YfbV conserved with MatP through evolution are required to impede the spreading of the constraining process to the rest of the chromosome. Our results unravel a site-specific system required to restrict to the Ter region the consequences of anchoring the Ter MD to the division machinery
    corecore