Intersections of Quadrics, Moment-angle Manifolds and Connected Sums

The topology of the intersection of two real homogeneous coaxial quadrics was studied by the second author who showed that its intersection with the unit sphere is in most cases diffeomorphic to a connected sum of sphere products. Combining that approach with a recent one (due to Antony Bahri, Martin Bendersky, Fred Cohen and the first author) we study here the intersections of k>2 quadrics and we identify very general families of such manifolds that are diffeomorphic to connected sums of sphere products. These include those moment-angle manifolds for which the result was conjectured by Frederic Bosio and Laurent Meersseman. As a byproduct, a simpler and neater proof of the result for the case k=2 is obtained. Two new sections contain results not included in the first version of this article: Section 2 describes the topological change on the manifolds after the operations of cutting off a vertex or an edge of the associated polytope, which can be combined in a special way with the previos results to produce new infinite families of manifolds that are connected sums of sphere products. In other cases we get slightly more complicated manifolds: with this we solve another question by Bosio-Meersseman about the manifold associated to the truncated cube. In Section 3 we use this to show that the known rules for the cohomology product of a moment-angle manifold have to be drastically modified in the general situation. We state the modified rule, but leave the details of this for another publication. Section 0 recalls known definitions and results and in section 2.1 some elementary topological constructions are defined and explored. In the Appendix we state and prove some results about specific differentiable manifolds, which are used in sections 1 and 2.Comment: We have included many clarifying suggestions and minor corrections from some colleagues who read the manuscript carefully. The only change in content from the previous version is the suppression a special case (item 3) of Theorem 1.3 because we have not been able to fill in the details of any of the known sketched proofs (including ours

MODERN CRYPTOGRAPHY

We live in an age where we willingly provide our social security number, credit card information, home address and countless other sensitive information over the Internet. Whether you are buying a phone case from Amazon, sending in an on-line job application, or logging into your on-line bank account, you trust that the sensitive data you enter is secure. As our technology and computing power become more sophisticated, so do the tools used by potential hackers to our information. In this paper, the underlying mathematics within ciphers will be looked at to understand the security of modern ciphers. An extremely important algorithm in today\u27s practice is the Advanced Encryption Standard (AES), which is used by our very own National Security Agency (NSA) for data up to TOP SECRET. Another frequently used cipher is the RSA cryptosystem. Its security is based on the concept of prime factorization, and the fact that it is a hard problem to prime factorize huge numbers, numbers on the scale of 2^{2048} or larger. Cryptanalysis, the study of breaking ciphers, will also be studied in this paper. Understanding effective attacks leads to understanding the construction of these very secure ciphers

Evaluation of human obstructive sleep apnea using computational fluid dynamics.

Obstructive sleep apnea (OSA) severity might be correlated to the flow characteristics of the upper airways. We aimed to investigate the severity of OSA based on 3D models constructed from CT scans coupled with computational fluid dynamics (CFD) simulations. The CT scans of seven adult patients diagnosed with OSA were used to reconstruct the 3D models of the upper airways and CFD modeling and analyses were performed. Results from the fluid simulations were compared with the apnea-hypopnea index. Here we show a correlation between a CFD-based parameter, the adjusted pressure coefficient (Cp*), and the respective apnea-hypopnea index (Pearson's r = 0.91, p = 0.004), which suggests that the anatomical-based model coupled with CFD could provide functional and localized information for different regions of the upper airways

Effects of the 2008-09 economic crisis on labor markets in Mexico

The 2008-09 economic crisis has had a long-lasting negative impact on the Mexican economy. This paper examines labor market dynamics in Mexico in light of the crisis. The labor market has been characterized in recent years by low relative unemployment, but high levels of informal jobs, low-growth, and almost stagnant real wages. In this context, the crisis destroyed a wide number of formal jobs, and even informal, increasing the unemployment rates to pre-crisis levels. Manufacturing was the sector that endured the largest job losses during the crisis and wages decreased for all sectors. The government of Mexico implemented a variety of programs to cope with the crises. However, these measures were too limited to counteract the large negative impact of the crisis on labor markets.Labor Markets,Labor Policies,Population Policies,Labor Standards,Economic Theory&Research

Audio Loop Station

A digital loop station is an electronic device that takes an analog audio signal, samples it with an Analog-to-Digital converter, stores it digitally in a system memory, and repeatedly outputs the content to a Digital-to-Analog converter. The signal is controlled by use of a microcontroller and amplified by external circuitry. The purpose of a digital loop station is to record and store an audio sample in real-time then playback the stored signal and superimpose additional audio signals over it. This project details a 16-bit digital loop station that samples at a rate of 44.1 kHz which is the industry standard for CD quality music. This loop station has three functions available to the user -- record, playback, or reset. Tests performed on the prototype demonstrated successful operation of the digital loop station. Two issues remain unresolved: high frequency noise at the analog output and a slight discontinuity in the processed audio waveform

A systematic review and meta-analysis of the diagnostic accuracy of the Phototest for cognitive impairment and dementia

The recently developed Phototest is a simple, easy and very brief test for detecting cognitive impairment or dementia. Objective: To evaluate the diagnostic accuracy of the Phototest for detecting cognitive impairment or dementia. METHODS: We used a manually created database to search for studies evaluating the Phototest diagnostic yield and performed an initial meta-analysis to determine sensitivity (Sn) and specificity (Sp) of diagnostic parameters. We also performed a second meta-analysis of individual participant data. RESULTS: In total, 6 studies were included in the meta-analysis. For dementia, Sn was 0.85 (95% CI, 0.82-0.88) and Sp 0.87 (95% CI, 0.85-0.99); for cognitive impairment, Sn was 0.80 (95% CI, 0.77-0.92) and Sp 0.88 (95% CI, 0.86-0.90). In the individual data meta-analysis, 1565 subjects were included, where best cut-off points for dementia and for cognitive impairment were 26/27 (Sn=0.89 (95% CI 0.85-0.91), Sp=0.84 (95% CI, 0.82-0.91)) and 28/29 (Sn=0.79 (95% CI, 0.76-0.81), Sp=0.88 (95% CI, 0.86-0.90)), respectively. CONCLUSION: Phototest has good diagnostic accuracy for dementia and cognitive impairment. It is brief, simple and can be used in illiterate persons. This makes it suitable for use in primary care settings and/or in subjects with low educational level.Phototest é um teste simples, fácil e muito rápido para detecção de comprometimento cognitivo e demência recentemente desenvolvido. Objetivo: Avaliar a acurácia diagnostica do Phototest para detecção de comprometimento cognitivo e demência. MÉTODOS: Nós usamos um banco de dados manualmente criado para estudos que avaliassem a capacidade diagnóstica do Phototest e realizamos uma meta-análise para determinar a sensibilidade (Sn) e especificidade (Ep) dos parâmetros diagnósticos. Nós também realizamos uma segunda meta-análise dos dados individuais dos participantes. RESULTADOS: Um total de seis estudos foram incluídos na meta-análise. Para demência a Sn foi 0.85 (95% CI, 0,82-0,88) e Ep 0,87 (95% CI, 0,85-0,99); para comprometimento cognitivo a Sn foi 0,80 (95% CI, 0,77-0,92) e Sp 0,88 (95% CI, 0,86-0,90). Na meta-análise de dados individuais, 1565 foram incluídos, os melhores escores de corte para demência e para comprometimento cognitivo foram 26/27 (Sn=0,89 (95% CI 0,85-0,91), Ep=0,84 (95% CI, 0,82-0,91)) e 28/29 (Sn=0,79 (95% CI, 0,76-0,81), Ep=0,88 (95% CI, 0,86-0,90)), respectivamente. CONCLUSÃO: Photest tem boa acurácia diagnostica para demência e comprometimento cognitivo. É breve, simples e pode ser usado em pessoas analfabetas. Tornando-o apropriado para o uso em cuidados primários e/ou sujeitos com baixo nível educacional.Fil: Carnero Pardo, Cristobal. Hospital Universitario Virgen de Las Nieves; España. Fidyan Neurocenter; EspañaFil: Lopez Alcalde Samuel. Fidyan Neurocenter; España. Hospital Universitario Virgen de Las Nieves; EspañaFil: Allegri, Ricardo Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para la Lucha Contra las Enfermedades Neurológicas de la Infancia. Instituto de Investigaciones Neurológicas ; ArgentinaFil: Russo, María Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para la Lucha Contra las Enfermedades Neurológicas de la Infancia. Instituto de Investigaciones Neurológicas ; Argentin

PPP in light rail transit systems in Spain

Light rail systems have proliferated in Spain in the last decade, following a tendency that is common not only in other European countries but also in other parts of the world. This paper reviews the benefits of light rail systems, both related to environmental issues and mobility issues. It analyses the evolution of light rail projects in Spain and shows that light rail systems in this country have evolved towards an extensive use of public-private partnerships. The analysis of the Spanish projects, however, does not contribute any conclusive evidence about whether public-private partnerships have been more efficient than publicly owned enterprises in building and operating light rail systems

Savoirs Statistiques et Curriculum Scolaire au Brésil

International audienceSThis is an issue that discuss statistic knowledges and your insertion in the Brazilian school curriculum of mathematics. First, we use the concept of "numeramentality" to express an analytical perspective that allows the study of knowledges which produce, organize and regulate the ways of thinking and acting in the contemporary and are based on the action to quantify, measure. Then we wonder about the risk as contemporary value to exercise the government of populations and individuals, and how it became a school curriculum component, which chooses the school theme and therefore the most appropriate knowledge. In this context, we note as the Brazilian curriculum agrees to demands and practices of the governmental order even though its knowledges have an epistemological importance. Finally, in our point of view, the use of themes such as inflation, growth, life expectancy for teaching Statistics provides the most political and social urgency in relation to ways of behaving face of the the risks and uncertainty. Finally, what is taught as statistical knowledge in school is only a form to be socially desirable subject.Il s’agit d’une discussion sur les savoirs statistiques et leur insertion dans le curriculum scolaire brésilien des mathématiques. En premier lieu, nous utilisons le concept de « numéramentalité » pour exprimer une perspective analytique adéquate à l’étude des savoirs capables de produire, organiser et régulariser des façons de penser et d’agir dans la contemporanéité basées sur la quantification, la codification, la mesure. Ensuite, nous nous interrogeons sur le risque comme question contemporaine de l’exercice de gouvernement des populations et des individus et sur comment cette notion devient une composante curriculaire scolaire qui orientent les thématiques et par conséquent, les savoirs choisis comme les plus adéquats. Dans ce cadre, nous remarquons que le curriculum scolaire brésilien est en accord avec les demandes et pratiques d’ordre gouvernemental même si ces savoirs revêtent une importance épistémologique. Enfin, à notre avis, l’usage de thématiques comme l’inflation, la croissance, l’espérance de vie pour l’enseignement de la Statistique répondent à une urgence politique et sociale en rapport avec les façons de se conduire devant les risques et les incertitudes. Pour ainsi dire, ce qui s’enseigne comme connaissance statistique à l’école n’est peut-être qu’une forme socialement souhaitable d’être suje

Lexico del tabú de la decencia utilizado por los jovenes homosexuales de la carrera de filologia y comunicacion de la UNAN-Managua, durante el segundo semestre del año 2013 y primer semestre de 2014

El presente trabajo monográfico es la recopilación del “Léxico del tabú de la decencia utilizado por los jóvenes homosexuales de la carrera de Filología y Comunicación de la UNAN- Managua, durante el segundo semestre del año 2013 y primer semestre de 2014” y tiene como objetivo principal contribuir al estudio del léxico en el habla nicaragüense a través del análisis del tabú de la decencia utilizado por los jóvenes homosexuales en estudio, y así aplicar las técnicas de la lexicografía moderna en el análisis de los vocablos encontrados para luego elaborar un glosario según la planta del Diccionario de Español de Nicaragua DEN (2009). El primer paso para su realización fue la revisión sobre trabajos relacionados al tema en estudio, para describir de manera general los antecedentes. Se visitó la Biblioteca Central de la UNAN-Managua, el Centro de Documentación Joaquín Pasos del departamento de español, el Centro de documentación de Psicología, la coordinación de la carrera, y posteriormente buscar el soporte teórico que sirviera como base para analizar y conceptualizar los aspectos que se consideraban de importancia para el fortalecimiento de la investigación. Después de obtener la base teórica, se procedió a ordenar el marco teórico. Primero se detallan los aspectos de la lingüística, (lengua y habla, niveles de la lengua etc.), la semántica (tipos de significados, antonimia, metáfora, tabú y su clasificación, las causas que originan el significado, eufemismos, disfemismos, aumentativos, diminutivos, lexicología, lexicografía, macroestructura y microestructura, y lo referente a la gramática. Luego se presenta una reseña histórica sobre los orígenes de la homosexualidad, y las teorías de origen genético, hormonal y psicosociales, que dan un vistazo a las causas de la homosexualidad. Posteriormente se expone el concepto de sexo y su clasificación, sexualidad, género, y todo lo actual en cuanto a conceptos de la diversidad sexual: (homosexual-gay, lesbiana, trasngéneros, bisexuales, etc.). Para la recopilación de los lemas se realizó un grupo focal con 15 estudiantes que admiten su homosexualidad, y se aplicaron 33 encuestas, de las cuales, 17 eran personas de Managua, y 16 de los departamentos, lo que ayudó a poner marca diatópica a los lemas; en total se habla de 48 jóvenes homosexuales que cumplían con la característica principal que regía la investigación, es decir, estudiantes de la carrera con tendencia homosexual. Posteriormente, se presentan la metodología y preguntas directrices, las cuales responden a los objetivos planteados en la investigación; además se detallan los métodos utilizados, el universo y muestra del trabajo, para presentar el glosario, análisis e interpretación de los resultados, conclusiones, recomendaciones y anexos del trabajo. Se recopilaron 488 vocablos, se clasificaron de acuerdo a las marcas gramaticales, y sociolingüísticas, y se aplicaron aspectos de la lexicografía moderna, para de esa manera demostrar la riqueza léxica del sector social que se estudiaba, en este caso los homosexuales. Es importante destacar la importancia de realizar estudios con sectores de la sociedad que son considerados minorías, pero que de una u otra manera dan un aporte a la lengua por su manera de hablar

Las concesiones de infraestructuras de transporte en los países de Centro y Este de Europa: influencia del entorno institucional

La necesidad de incrementar de modo significativo sus niveles de inversión en infraestructuras de transporte, unida a las exigencias en materia de control del déficit presupuestario y de la deuda pública, conducen a los países recientemente incorporados a la Unión Europea a una apuesta por los mecanismos de participación del sector privado, principalmente a través de concesiones. Además, se trata de un planteamiento impulsado por la propia Comisión Europea para todos los países de la Unión Europea. En este artículo se analizan algunos de los principales problemas a los que se enfrentan los países recientemente incorporados a la Unión Europea en su empeño por avanzar en el desarrollo del sistema concesional, que son en buena medida problemas derivados de la complejidad de los proyectos concesionales y de las deficiencias del entorno institucional en estos países. - The need to significantly increase investment levels in transport infrastructures, together with the requirements for control of budgetary deficit and public debt, has led to the backing by countries recently incorporated in the European Union for private sector participation methods, mainly through concessions. This is, in fact, the focus promoted by the European Commission for all EU countries. This article examines some of the main problems affecting the new members of the EU when attempting to develop the concessionary system and which are largely related to the complexity of the concession project itself and the defects in the institutional environment in these countries