Analytical approximations to the spectra of quark-antiquark potentials

A method, recently devised to obtain analytical approximations to certain classes of integrals, is used in combination with the WKB expansion to derive accurate analytical expressions for the spectrum of quantum potentials. The accuracy of our results is verified by comparing them both with the literature on the subject and with the numerical results obtained with a Fortran code. As an application of the method that we propose, we consider the meson spectroscopy with various phenomenological potentials.Comment: 12 pages, 4 figures, 1 tabl

Esbozo de la astronomía en El Salvador: de la contemplación a la promesa científica

Época antigua. De la colonia al siglo XIX. Siglo XX, del desatino a la guerra. Del Halley al Eclipse de 1991. Siglo XXI

NERVE FIBER DIAMETER MEASUREMENTS USING HEMATOXYLIN AND EOSIN STAINING AND BRIGHTFIELD MICROSCOPY TO ASSESS THE NOVEL METHOD OF CHARACTERIZING PERIPHERAL NERVE FIBER DISTRIBUTIONS BY GROUP DELAY

Peripheral neuropathies are a set of common diseases that affect the peripheral nervous system, causing damage to vital connections between various parts of the body and the brain and spinal cord. Different clinical conditions are known to selectively impact various size nerve fibers, which often makes it difficult to diagnose which peripheral neuropathy a patient might have. The nerve conduction velocity diagnostic test provides clinically useful information in the diagnosis of some peripheral neuropathies. This method is advantageous because it tends to be minimally invasive yet it provides valuable diagnostic information. However, this test does not determine characteristics of peripheral nerve fiber size distributions, and therefore does not show any detailed information regarding the nerve fibers within the nerve trunk. Being able to determine which nerve fibers are contributing to the evoked potential within a nerve trunk could provide additional information to clinicians for the diagnosis of specific pathologies of the peripheral nervous system, such as chronic inflammatory demyelinating polyneuropathy or early diabetic peripheral neuropathy. In this study, three rat sciatic nerves are sectioned and stained with hematoxylin and eosin in order to measure the nerve fiber diameters within the nerve trunk. Stained samples are viewed using brightfield microscopy and images are analyzed using ImageJ. Histograms were created to show the frequency of various nerve fiber diameters. The nerve fiber diameters measured during this research are consistent with the range of previously published diameter values and will be used to support continuing research for a novel method to characterize peripheral nerve fiber size distributions using group delay

Alineación Astronómica de la Estructura 7 del Sitio Arqueológico San Andrés, El Salvador

El presente artículo presenta un estudio arqueoastronómico de la Estructura 7 del sitio arqueológico San Andrés, en El Salvador. La estructura, fechada en el período clásico terminal, posee una marcada alineación con respecto al ocaso solar durante el solsticio de verano. This paper is a study of the Structure number 7 in San Andrés, archaeological sitein El Salvador. The structure dated to the Terminal Classic period and shows a strong alignment with the sunset in the summer solstice

Estado de salud y autocuidado en adultos expuestos a enfermedad cardiovascular

Tesis (Maestría en Ciencias de Enfermería con Enfasis en Salud Comunitaria) UANLUANLhttp://www.uanl.mx

Historia del diseño en El Salvador: El Diseño Gráfico como profesión formal (1978-1988)

El presente artículo trata sobre la historia del diseño gráfico en El Salvador, desde principios del siglo XX hasta 1988, cuando se formaliza como profesión en la Universidad Dr. José Matías Delgado

A carta Laudato si' do Papa Francisco: de objeto de ataque a documento ignorado.

Varios puntos de la Carta Laudato si' chocan de frente con la doctrina económica hegemónica y con políticos alineados que la defienden. Es el documento pontificio más notable que trata, de manera sistemática, los temas ecológicos presentados con un análisis articulador de las principales dimensiones de los problemas que aquejan “a nuestra casa común”. Una de sus características más destacadas es la superación de aproximaciones reduccionistas y unidisciplinarias excluyentes, con la propuesta de construir un enfoque integrador. Desde este ve todos los problemas diagnosticados, que afectan la vida del planeta Tierra, como consecuencias del paradigma tecnocrático dominante ‒dominante al punto de que se constituye en un paradigma de comprensión que condiciona la vida de las personas y el funcionamiento de la sociedad donde las finanzas continúan ahogando a la economía real‒. Para Francisco, es una concepción mágica del mercado, porque tiende a pensar que los problemas se resuelven solo con el crecimiento de los beneficios de empresas y de individuos. Tremendamente riesgoso que el poder tecnocientífico de este paradigma resida en una pequeña parte de la humanidad. Un paradigma alternativo implicaría, entre otras cosas, redefinir concepto y práctica de progreso; proponer soluciones desde la perspectiva de todos los afectados, establecer límites infranqueables a la protección de los ecosistemas, crear empleo promoviendo una economía que favorezca la diversidad productiva y la creatividad empresarial. Requiere cambiar la mentalidad, el modelo de desarrollo global y cuestionar la lógica subyacente en la cultura actual, de manera que se avance hacia una valiente revolución cultural.Several points of the Laudato si' Letter clash head-on with the hegemonic economic doctrine and with aligned politicians who defend it. It is the most notable pontifical document that deals systematically with ecological issues, presenting an articulating analysis of the main dimensions of the problems that afflict “our common home”. One of its most outstanding characteristics is the overcoming of reductionist and unidisciplinary excluding approaches, with the proposal to build an integrative approach. From this perspective, it sees all the problems diagnosed, which affect life on planet Earth, as consequences of the dominant technocratic paradigm ‒dominant to the point that it constitutes a paradigm of understanding that conditions people’s lives and the functioning of society, where finance continues to drown the real economy. For Francisco, it is a fabricated conception of the market, because it tends to think that problems are solved only with the growth of the profits of companies and individuals. It is tremendously risky that the techno-scientific power of this paradigm resides in a small part of humanity. An alternative paradigm would imply, among other things: redefining the concept and practice of progress, proposing solutions from the perspective of all those affected, establishing insurmountable limits to the protection of ecosystems, creating jobs by promoting an economy that favors productive diversity and entrepreneurial creativity. It requires changing the mentality, the global development model and questioning the logic underlying the current culture, moving towards a courageous cultural revolution.Vários pontos da Carta Laudato si' colidem frontalmente com a doutrina econômica hegemônica e com políticos alinhados que a defendem. É o documento pontifício mais notável que trata sistematicamente as questões ecológicas apresentadas com uma análise articulada das principais dimensões dos problemas que afligem “nossa casa comum”. Uma de suas características mais marcantes é a superação de abordagens reducionistas excludentes e unidisciplinares, com a proposta de construir uma abordagem integradora. A partir disso, ele vê todos os problemas diagnosticados que afetam a vida no planeta Terra, como consequências do paradigma tecnocrático dominante ‒dominante a ponto de constituir um paradigma de compreensão que condiciona a vida das pessoas e o funcionamento da sociedade onde as finanças continuam a sufocar a economia real‒. Para Francisco, trata-se de uma concepção mágica do mercado, pois tende a pensar que os problemas só se resolvem com o crescimento dos lucros das empresas e dos indivíduos. É tremendamente arriscado que o poder tecno-científico desse paradigma resida em uma pequena parte da humanidade. Um paradigma alternativo implicaria, entre outras coisas, redefinir o conceito e a prática do progresso; propor soluções na perspectiva de todos os afetados, estabelecer limites intransponíveis para a proteção dos ecossistemas, criar emprego promovendo uma economia que favoreça a diversidade produtiva e a criatividade empresarial. É preciso mudar a mentalidade, o modelo de desenvolvimento global e questionar a lógica subjacente à cultura atual, para avançar em direção a uma corajosa revolução cultural

The Structural Information Filtered Features Potential for Machine Learning calculations of energies and forces of atomic systems.

In the last ten years, machine learning potentials have been successfully applied to the study of crystals, and molecules. However, more complex materials like clusters, macro-molecules, and glasses are out reach of current methods. The input of any machine learning system is a tensor of features (the most universal type are rank 1 tensors or vectors of features), the quality of any machine learning system is directly related to how well the feature space describes the original physical system. So far, the feature engineering process for machine learning potentials can not describe complex material. The current methods are highly inefficient transforming the information of the physical structure into the feature vector, the losses of information constraint the accuracy of machine learning potentials. This work introduces the Structural Information Filtered Features (SIFF), the SIFF is a feature engineering method, based on maximizing the transfer of information from the physical structure to the feature space. The SIFF are thought as a universal feature, universal in two senses. First is able to describe complex systems, as well as molecules, and crystals. Second it can be easily used as input for any machine learning algorithm. When applied to crystals the SIFF does as well as the best feature engineering methods for this materials (SOAP, CGNN). When applied to molecules the SIFF performs better than the Bag of Bonds method, especially when the number of structures is reduced to less than 10000, in this conditions the SIFF shows a superior performance, due to its superior information transference. Whit respect to complex system, the SIFF is compared to the Behler and Parrinello approach, here the SIFF method reach an error of 0.083 eV/structure in 18110 second, in contrast the Behler and Parrinello method achieved and error of 0.109 eV/structure in 61969 seconds. The main disadvantage of the SIFF method is that the conventionality of the feature space grows exponentially with the number of chemical species in the system