Study Of Tachyon Dynamics For Broad Classes of Potentials

We investigate in detail the asymptotic properties of tachyon cosmology for a broad class of self-interaction potentials. The present approach relies in an appropriate re-definition of the tachyon field, which, in conjunction with a method formerly applied in the bibliography in a different context, allows to generalize the dynamical systems study of tachyon cosmology to a wider class of self-interaction potentials beyond the (inverse) square-law one. It is revealed that independent of the functional form of the potential, the matter-dominated solution and the ultra-relativistic (also matter-dominated) solution, are always associated with equilibrium points in the phase space of the tachyon models. The latter is always the past attractor, while the former is a saddle critical point. For inverse power-law potentials $V\propto\phi^{-2\lambda}$ the late-time attractor is always the de Sitter solution, while for sinh-like potentials $V\propto\sinh^{-\alpha}(\lambda\phi)$, depending on the region of parameter space, the late-time attractor can be either the inflationary tachyon-dominated solution or the matter-scaling (also inflationary) phase. In general, for most part of known quintessential potentials, the late-time dynamics will be associated either with de Sitter inflation, or with matter-scaling, or with scalar field-dominated solutions.Comment: 13 pages, latex, 4 eps figures. Title changed, authors added, motivation rewritten, discussion improved, references added. To match the published versio

Latinx Immigrant Families With Youth With Disabilities Participating in Civic Engagement to Promote Social Justice

Vulnerable populations are exposed to several disparities and inequalities representing an infringement of social justice and limiting their opportunities to live healthy and fulfilling lives. Latinx immigrant families with youth and young adults with disabilities represent one such vulnerable population. The purpose of this article is to describe and discuss the participation of Latinx immigrant families of youth and young adults with disabilities in two interrelated civic engagement projects aimed at promoting social justice and community participation. First, we will discuss the conceptual framework of social justice that grounded these cases of civic engagement, and then we will describe two case studies. Both cases of civic engagement emerged from Latinx immigrant families as part of meaningful conversations they had with the research team related to healthy lifestyles and community participation. The first case of civic engagement addresses walkability safety, and the second describes a community-engaged asset-mapping process. These two cases of civic engagement provided participants an opportunity to advocate for justice. Finally, we discuss the implications and challenges that vulnerable populations experience in making their voices heard by those in positions of power

Formative E-Assessment of Schema Acquisition in the Human Lexicon as a Tool in Adaptive Online Instruction

This chapter presents a comprehensive method of implementing e-assessment in adaptive e-instruction systems. Specifically, a neural net classifier capable of discerning whether a student has integrated new schema-related concepts from course content into her/his lexicon is used by an expert system with a database containing natural mental representations from course content obtained from students and teachers for adapting e-instruction. Mental representation modeling is used to improve student modeling. Implications for adaptive hypermedia systems and hypertext-based instructions are discussed. Furthermore, it is argued that the current research constitutes a new cognitive science empirical direction to evaluate knowledge acquisition based on meaning information

Model for High-Throughput Screening of drug immunotoxicity - study of the antimicrobial G1 over peritoneal macrophages using flow cytometry

Modelos matematicos y citometriaQuantitative Structure-Activity (mt-QSAR) techniques may become an important tool for prediction of cytotoxicity and High-throughput Screening (HTS) of drugs to rationalize drug discovery process. In this work, we train and validate by the first time mt-QSAR model using TOPS-MODE approach to calculate drug molecular descriptors and Linear Discriminant Analysis (LDA) function. This model correctly classifies 8,258 out of 9,000 (Accuracy = 91.76%) multiplexing assay endpoints of 7903 drugs (including both train and validation series). Each endpoint correspond to one out of 1418 assays, 36 molecular and cellular targets, 46 standard type measures, in two possible organisms (human and mouse). After that, we determined experimentally, by the first time, the values of EC50 = 21.58 μg/mL and Cytotoxicity = 23.6 % for the anti-microbial / antiparasite drug G1 over Balb/C mouse peritoneal macrophages using flow cytometry. In addition, the model predicts for G1 only 7 positive endpoints out 1,251 cytotoxicity assays (0.56% of probability of cytotoxicity in multiple assays). The results obtained complement the toxicological studies of this important drug. This work adds a new tool to the existing pool of few methods useful for multi-target HTS of ChEMBL and other libraries of compounds towards drug discovery.Conacy

Cellular Senescence in Livers from Children with End Stage Liver Disease

Senescent cells occur in adults with cirrhotic livers independent of the etiology. Aim: Investigate the presence rate of cellular senescence and expression of cell cycle check points in livers from children with end stage disease. staining occurred in the areas of ductular transformation and in the interlobular bile ducts.Cellular senescence in livers of children with end stage disease is associated with damage rather than corresponding to an age dependent phenomenon. Further studies are needed to support the hypothesis that these senescence markers correlate with disease progression

Impacto de los proveedores autorizados de la Universidad Nacional Autónoma de México en el desarrollo de colecciones de las bibliotecas de humanidades

The impact of the suppliers authorized by the Directorate General of libraries (DGB) of the National Autonomous University of Mexico (UNAM) in the development of collections of the libraries of the subsystem of Humanities at the University is analysed through direct observation and the application of questionnaires both to the acquisition staff and the suppliers authorized by the DGB. Acquisitions managers claim the program has been very successful, but also that more than half of the list of providers do not cover the geographic area of study of the research projects carried out by the community of users, and occasionally the have to seek their materials outside this list. Therefore, it is necessary to pay attention to the list of providers that work with editorials that publish in the field of Humanities, so that more countries in Latin America are covered. It is recommended that each subsystem library commission considers a meeting with the DGB-authorized bibliographic providers to explain them the research projects of their users and reinforce the knowledge they have of the specialty of each library.Se analiza el impacto de los proveedores autorizados por la Dirección General de Bibliotecas (DGB) de la Universidad Nacional Autónoma de México (UNAM) en el desarrollo de colecciones de las bibliotecas de su Subsistema de Humanidades. Se utilizó la observación directa y la aplicación de cuestionarios a los encargados del área de adquisiciones bibliográficas de las bibliotecas y a los proveedores autorizados. En general, el programa ha sido un éxito, pero los encargados de adquisiciones declaran que más de la mitad de la lista de proveedores no cubre el área geográfica de estudio de los proyectos de investigación que realiza su comunidad de usuarios. Es necesario, por tanto, asegurar que la lista de proveedores de editoriales relacionadas con las humanidades abarque en mayor medida a todos los países de América Latina. Se recomienda que la comisión de Biblioteca de cada biblioteca del Subsistema considere una reunión con los proveedores de material bibliográfico autorizados por la DGB para explicarles los proyectos y líneas de investigación de su dependencia y reforzar el conocimiento que tienen de la especialidad de cada biblioteca

A Pilot Study of the Association of Tumor Necrosis Factor Alpha Polymorphisms with Psoriatic Arthritis in the Romanian Population

Tumor necrosis factor alpha (TNF-alpha) is an important pro-inflammatory cytokine implicated in the pathogenesis of psoriatic arthritis. We have performed a case-control association study of three TNF-alpha gene polymorphisms in a group of Romanian psoriatic arthritis patients versus ethnically matched controls. A second group of patients with undifferentiated spondyloarthritis was used in order to look for similarities in the genetic background of the two rheumatic disorders. The −857C/T polymorphism was associated with susceptibility to psoriatic arthritis in our population at the individual level (p = 0.03, OR 1.65, 95% CI 1.05–2.57) and in combined haplotypes with the −238G/A and −308G/A SNPs. Regarding the investigated polymorphisms and derived haplotypes, no potential association was found with the susceptibility to undifferentiated spondyloarthritis in Romanian patients