WKB formalism and a lower limit for the energy eigenstates of bound states for some potentials

In the present work the conditions appearing in the WKB approximation formalism of quantum mechanics are analyzed. It is shown that, in general, a careful definition of an approximation method requires the introduction of two length parameters, one of them always considered in the text books on quantum mechanics, whereas the second one is usually neglected. Afterwards we define a particular family of potentials and prove, resorting to the aforementioned length parameters, that we may find an energy which is a lower bound to the ground energy of the system. The idea is applied to the case of a harmonic oscillator and also to a particle freely falling in a homogeneous gravitational field, and in both cases the consistency of our method is corroborated. This approach, together with the Rayleigh--Ritz formalism, allows us to define an energy interval in which the ground energy of any potential, belonging to our family, must lie.Comment: Accepted in Modern Physics Letters

Efficient functional built-in test for RF systems using two-tone response envelope analysis

Trabajo presentado al AFRICON celebrado en Nairobi del 23 al 25 de septiembre de 2009.This paper presents a novel and low-cost methodology that can be used for testing RF blocks embedded in complex SoCs. It is based on the detection and spectral analysis of the two-tone response envelope of the block under test. The main non-linearity specifications of the block under test can be easily extracted from the envelope signal. The analytical basis of the proposed methodology is demonstrated, and a proposal for its implementation as a built-in test core is discussed. Finally, practical simulation examples show the feasibility of the approach.This work has been partially supported by the Spanish Ministry of Innovation through project TEST (TEC2007-68072/MIC) and CATRENE's project TOETS.Peer Reviewe

State-selective electron capture in collisions of ground and metastable N2+ ions with H(1s)

9 págs.; 12 figs.; 1 tab.; PACS number(s): 34.70.1e, 34.10.1xA calculation of the electron capture (EC) cross sections for collisions of metastable and ground states of nitrogen2+ ions with H(1s) was presented. The double translational energy spectroscopy technique facilitated the energy change spectrum in EC to be measured for an incident pure beam of ground state ions. It was found that the nuclear wave functions were derived by solving numerically the system of differential equations. It was observed that for impact energies 1 KeV, the impact parameter method was employed, where the nuclei followed straightline trajectories with constant relative velocity V and impact parameter b (R=b+vt). ©2004 The American Physical SocietyI.R. is grateful to the Spanish MCyT for a “Contrato Ramón y Cajal.” This work has been partially supported by DGICYT Projects No. BFM2000-0025 and FTN2000-0911.Peer Reviewe

Isotropic and Anisotropic Bouncing Cosmologies in Palatini Gravity

We study isotropic and anisotropic (Bianchi I) cosmologies in Palatini $f(R)$ and $f(R,R_{\mu\nu}R^{\mu\nu})$ theories of gravity and consider the existence of non-singular bouncing solutions in the early universe. We find that all $f(R)$ models with isotropic bouncing solutions develop shear singularities in the anisotropic case. On the contrary, the simple quadratic model $R+a R^2/R_P+R_{\mu\nu}R^{\mu\nu}/R_P$ exhibits regular bouncing solutions in both isotropic and anisotropic cases for a wide range of equations of state, including dust (for $a<0$) and radiation (for arbitrary $a$). It thus represents a purely gravitational solution to the big bang singularity and anisotropy problems of general relativity without the need for exotic ($w>1$) sources of matter/energy.Comment: 25 pages, 7 figure

Essential thrombocythaemia in a child of three years

AbstractEssential thrombocythaemia is a rare pathology in adults and extremely rare in children, making it a diagnostic challenge for paediatricians. The challenge is greater when patients are asymptomatic, despite an incidental discovery of thrombocytosis.We report the case of extreme thrombocytosis found in an asymptomatic child of 3 years with no personal history or familial history. Study protocol started by ruling out laboratory errors, infectious disease, haemolytic anaemia, iron deficiency anaemia and autoimmune diseases. Bone marrow sample confirmed elevated megakaryocyte production, with other cell lines within normal ranges. Genetic analysis (including JAK2 mutation) was also negative, leading to a differential diagnosis of essential thrombocythaemia. Hydroxyurea (10mg/kg) and aspirin (5mg/kg) were prescribed. A moderate reduction in platelet count was achieved after 4 weeks of treatment

Improving the accuracy of RF alternate test using multi-VDD conditions: application to envelope-based test of LNAs

Trabajo presentado al "20 Asina Test Symposium" celebrado en Nueva Delhi (India) del 20 al 23 de Noviembre del 2011.-- Reprinted from (relevant publication info). This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the products or services of CSIC Spanish National Research Council, Digital.CSIC. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.This work demonstrates that multi-VDD conditions may be used to improve the accuracy of machine learning mod- els, significantly decreasing the prediction error. The proposed technique has been successfully applied to a previous alternate test strategy for LNAs based on response envelope detection. A prototype has been developed to show its feasibility. The prototype consists of a low-power 2.4GHz LNA and a simple envelope detector, integrated in a 90nm CMOS technology. Post- layout simulation results are provided to verify the functionality of the approach. Copyright © 2011 IEEE.This work has been partially funded by a CSIC JAE-Doc contract (cofinanced by FSE), a Spanish MAE-AECID grant and projects: SR2 - Short Range Radio (Catrene European project 2A105SR2 and Avanza I+D Spanish project TSI-020400-2010-55, cofinanced with FEDER program), Auto-calibración y auto-test en circuitos analógicos, mixtos y de radio frecuencia (Andalusian Government project P09-TIC-5386, cofinanced with FEDER program), and Catrene project TOETS (CT 302).Peer reviewe

Luces y sombras del análisis de expresión génica utilizando microarrays. Un ejemplo en cerdo ibérico

Ponencia publicada en ITEA, vol.104La tecnología de los microarrays de expresión es la herramienta ideal para el estudio de patrones de expresión de miles de genes de forma simultánea. Sin embargo existe gran variabilidad de resultados atribuible a los aspectos técnicos y de análisis estadístico. En este trabajo presentamos algunos de los problemas surgidos en el estudio de las diferencias de expresión en hígado de cerdos ibéricos para los tratamientos sexo y alimentación empleando microarrays de Affymetrix. Los datos de expresión normalizados fueron analizados siguiendo dos aproximaciones de la metodología de los modelos mixtos. Para ambos tratamientos las diferencias de expresión detectadas fueron dependientes del modelo de análisis y solo un pequeño número de genes diferencialmente expresados fueron coincidentes en ambas estrategias estadísticas. Algunas de estas diferencias de expresión fueron validadas por PCR cuantitativa. Además identificamos errores de diseño y falta de anotación de las sondas del array. Los resultados de este estudio nos han permitido detectar diferencias de expresión de algunos genes de interés, pero también remarcan la necesidad de realizar estudios complementarios que confirmen las diferencias de expresión reveladas a través de la tecnología de los microarraysLights and darkness of gene expression analysis using microarrays: an example in Iberian pigs Expression microarray technology is the ideal tool for the study of thousands of gene expression patterns simultaneously. However there is a great variability of results attributed to technical and statistical analysis aspects. In this work we present several of the arisen problems of a differential expression study in liver of Iberian pigs under the treatments sex and feeding level using Affymetrix microarray. Normalized expression data were analyzed following two approaches of the mixed model methodology. In both treatments the detected differential expressions were dependent of the statistical model and just a small number of genes were coincident between both statistical strategies. Some of the expression differences were confirmed by quantitative PCR. Besides, we have identified design mistakes and missing annotation of the array probes. The results of this study have allowed us to detect differential expression of interesting genes, but it pointed out the necessity of carrying out complementary studies in order to confirm the differential expressions revealed using microarrays technology

Swelling properties of alkali-metal doped polymeric anion-exchange membranes in alcohol media for application in fuel cells

Swelling properties of four commercial anion-exchange membranes with different structure have been analyzed in several hydro-organic media. With this target, the liquid uptake and the surface expansion of the membranes in contact with different pure liquids, water and alcohols (methanol, ethanol and 1-propanol), and with water alcohol mixtures with different concentrations have been experimentally determined in presence and in absence of an alkaline medium (LiOH, NaOH and KOH of different concentrations). The alkali-metal doping effect on the membrane water uptake has also been investigated, analyzing the influence of the hydroxide concentration and the presence of an alcohol in the doping solution. The results show that the membrane structure plays an essential role in the influence that alcohol nature and alkaline media has on the selective properties of the membrane. The heterogeneous membranes, with lower density, show higher liquid uptakes and dimensional changes than the homogeneous membranes, regardless of the doping conditions. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved