Spectral properties of random graphs with fixed equitable partition

We define a graph to be $S$-regular if it contains an equitable partition given by a matrix $S$. These graphs are generalizations of both regular and bipartite, biregular graphs. An $S$-regular matrix is defined then as a matrix on an $S$-regular graph consistent with the graph's equitable partition. In this paper we derive the limiting spectral density for large, random $S$-regular matrices as well as limiting functions of certain statistics for their eigenvector coordinates as a function of eigenvalue. These limiting functions are defined in terms of spectral measures on $S$-regular trees. In general, these spectral measures do not have a closed-form expression; however, we provide a defining system of polynomials for them. Finally, we explore eigenvalue bounds of $S$-regular graph, proving an expander mixing lemma, Alon-Bopana bound, and other eigenvalue inequalities in terms of the eigenvalues of the matrix $S$.Comment: 24 pages, 3 figure

Neighborhood Homogeneous Labelings of Graphs

Given a labeling of the vertices and edges of a graph, we define a type of homogeneity that requires that the neighborhood of every vertex contains the same number of each of the labels. This homogeneity constraint is a generalization of regularity – all such graphs are regular. We consider a specific condition in which both the edge and vertex label sets have two elements and every neighborhood contains two of each label. We show that vertex homogeneity implies edge homogeneity (so long as the number of edges in any neighborhood is four), and give two theorems describing how to build new homogeneous graphs (or multigraphs) from others. Keywords: vertex labeling; edge labeling; homogenous graph; regular graph 1

Zika Virus Outside Africa

This should be considered an emerging pathogen

A computational framework to emulate the human perspective in flow cytometric data analysis

Background: In recent years, intense research efforts have focused on developing methods for automated flow cytometric data analysis. However, while designing such applications, little or no attention has been paid to the human perspective that is absolutely central to the manual gating process of identifying and characterizing cell populations. In particular, the assumption of many common techniques that cell populations could be modeled reliably with pre-specified distributions may not hold true in real-life samples, which can have populations of arbitrary shapes and considerable inter-sample variation. <p/>Results: To address this, we developed a new framework flowScape for emulating certain key aspects of the human perspective in analyzing flow data, which we implemented in multiple steps. First, flowScape begins with creating a mathematically rigorous map of the high-dimensional flow data landscape based on dense and sparse regions defined by relative concentrations of events around modes. In the second step, these modal clusters are connected with a global hierarchical structure. This representation allows flowScape to perform ridgeline analysis for both traversing the landscape and isolating cell populations at different levels of resolution. Finally, we extended manual gating with a new capacity for constructing templates that can identify target populations in terms of their relative parameters, as opposed to the more commonly used absolute or physical parameters. This allows flowScape to apply such templates in batch mode for detecting the corresponding populations in a flexible, sample-specific manner. We also demonstrated different applications of our framework to flow data analysis and show its superiority over other analytical methods. <p/>Conclusions: The human perspective, built on top of intuition and experience, is a very important component of flow cytometric data analysis. By emulating some of its approaches and extending these with automation and rigor, flowScape provides a flexible and robust framework for computational cytomics

Representing complex data using localized principal components with application to astronomical data

Often the relation between the variables constituting a multivariate data space might be characterized by one or more of the terms: ``nonlinear'', ``branched'', ``disconnected'', ``bended'', ``curved'', ``heterogeneous'', or, more general, ``complex''. In these cases, simple principal component analysis (PCA) as a tool for dimension reduction can fail badly. Of the many alternative approaches proposed so far, local approximations of PCA are among the most promising. This paper will give a short review of localized versions of PCA, focusing on local principal curves and local partitioning algorithms. Furthermore we discuss projections other than the local principal components. When performing local dimension reduction for regression or classification problems it is important to focus not only on the manifold structure of the covariates, but also on the response variable(s). Local principal components only achieve the former, whereas localized regression approaches concentrate on the latter. Local projection directions derived from the partial least squares (PLS) algorithm offer an interesting trade-off between these two objectives. We apply these methods to several real data sets. In particular, we consider simulated astrophysical data from the future Galactic survey mission Gaia.Comment: 25 pages. In "Principal Manifolds for Data Visualization and Dimension Reduction", A. Gorban, B. Kegl, D. Wunsch, and A. Zinovyev (eds), Lecture Notes in Computational Science and Engineering, Springer, 2007, pp. 180--204, http://www.springer.com/dal/home/generic/search/results?SGWID=1-40109-22-173750210-

Programa de saneamento da água de poços rasos de escolas públicas rurais do município de Ibiúna-SP

This work had the objective to implant the sanitation program of groundwater in all rural schools in the District of Ibiúna-SP. In order to execute it, samples were collected in 50 schools before and after the interventions, for microbiological and physical-chemistry analyses. It was identified the main contamination risk factors. It was installed alternative systems of chlorine and fluoridation and developed educative actions with the involved persons in this work. The microbiological result, after interventions, showed that the program was satisfactory, with the absence of coli forms in all samples after interventions. The association and the inclusion of fluorine permitted adequate concentrations of that element in the water. About risk contamination factors, the more important was the maintenance, information, quality control of water and hygienic conditions and conservation of reservoirs. The education in the health of involved persons was important for the maintenance and enlargement of the program.Este trabajo tuvo por objetivo implantar programa de sanidad del agua de pozos rasos de todas las escuelas de la zona rural de la Municipalidad de Ibiúna. Para su ejecución fueron recogidas muestras de agua en 50 escuelas antes y después de las intervenciones, para análisis microbiológico y físico químico. Fueron identificados los principales factores de riesgo de contaminación del agua, fueron instalados sistemas alternativos de aplicación de cloro y flúor, y desarrolladas acciones educativas con las personas envueltas en el trabajo. El resultado microbiológico, después de las intervenciones, mostró que el programa fue satisfactorio y presentó ausencia de coliformes en todas las muestras pós- intervención. La asociación e inclusión de flúor permitió concentraciones adecuadas de este elemento en el agua. Sobre factores de riesgo de contaminación, los más destacados fueron la manutención, la información, el control de la calidad del agua y las condiciones de higiene y conservación de los reservatorios. La educación sanitaria de las personas envueltas fue fundamental para la manutención y ampliación del programa.Este trabalho teve por objetivo implantar o programa de saneamento da água de poços rasos de todas as escolas da zona rural do Município de Ibiúna. Para a sua realização, foram colhidas amostras de água em 50 escolas, antes e após as intervenções, para análise microbiológica e físico-química. Foram identificados os principais fatores de risco de contaminação da água. Foram instalados sistemas alternativos de cloração e fluoretação e, ainda, desenvolvidas ações educativas com as pessoas envolvidas no trabalho. O resultado microbiológico, após as intervenções, mostrou que o programa foi satisfatório, com a ausência de coliformes em todas as amostras pósintervenção. A associação e a inclusão do flúor permitiu concentrações adequadas deste elemento na água. Sobre os fatores de risco de contaminação, os mais importantes foram a manutenção, informação, controle de qualidade da água e condições de higiene e conservação dos reservatórios. A educação em saúde das pessoas envolvidas foi importante para a manutenção e ampliação do programa

Programa de saneamento da água de poços rasos de escolas públicas rurais do município de Ibiúna-SP

This work had the objective to implant the sanitation program of groundwater in all rural schools in the District of Ibiúna-SP. In order to execute it, samples were collected in 50 schools before and after the interventions, for microbiological and physical-chemistry analyses. It was identified the main contamination risk factors. It was installed alternative systems of chlorine and fluoridation and developed educative actions with the involved persons in this work. The microbiological result, after interventions, showed that the program was satisfactory, with the absence of coli forms in all samples after interventions. The association and the inclusion of fluorine permitted adequate concentrations of that element in the water. About risk contamination factors, the more important was the maintenance, information, quality control of water and hygienic conditions and conservation of reservoirs. The education in the health of involved persons was important for the maintenance and enlargement of the program.Este trabajo tuvo por objetivo implantar programa de sanidad del agua de pozos rasos de todas las escuelas de la zona rural de la Municipalidad de Ibiúna. Para su ejecución fueron recogidas muestras de agua en 50 escuelas antes y después de las intervenciones, para análisis microbiológico y físico químico. Fueron identificados los principales factores de riesgo de contaminación del agua, fueron instalados sistemas alternativos de aplicación de cloro y flúor, y desarrolladas acciones educativas con las personas envueltas en el trabajo. El resultado microbiológico, después de las intervenciones, mostró que el programa fue satisfactorio y presentó ausencia de coliformes en todas las muestras pós- intervención. La asociación e inclusión de flúor permitió concentraciones adecuadas de este elemento en el agua. Sobre factores de riesgo de contaminación, los más destacados fueron la manutención, la información, el control de la calidad del agua y las condiciones de higiene y conservación de los reservatorios. La educación sanitaria de las personas envueltas fue fundamental para la manutención y ampliación del programa.Este trabalho teve por objetivo implantar o programa de saneamento da água de poços rasos de todas as escolas da zona rural do Município de Ibiúna. Para a sua realização, foram colhidas amostras de água em 50 escolas, antes e após as intervenções, para análise microbiológica e físico-química. Foram identificados os principais fatores de risco de contaminação da água. Foram instalados sistemas alternativos de cloração e fluoretação e, ainda, desenvolvidas ações educativas com as pessoas envolvidas no trabalho. O resultado microbiológico, após as intervenções, mostrou que o programa foi satisfatório, com a ausência de coliformes em todas as amostras pósintervenção. A associação e a inclusão do flúor permitiu concentrações adequadas deste elemento na água. Sobre os fatores de risco de contaminação, os mais importantes foram a manutenção, informação, controle de qualidade da água e condições de higiene e conservação dos reservatórios. A educação em saúde das pessoas envolvidas foi importante para a manutenção e ampliação do programa

A network linking scene perception and spatial memory systems in posterior cerebral cortex

The neural systems supporting scene-perception and spatial-memory systems of the human brain are well-described. But how do these neural systems interact? Here, using fine-grained individual-subject fMRI, we report three cortical areas of the human brain, each lying immediately anterior to a region of the scene perception network in posterior cerebral cortex, that selectively activate when recalling familiar real-world locations. Despite their close proximity to the scene-perception areas, network analyses show that these regions constitute a distinct functional network that interfaces with spatial memory systems during naturalistic scene understanding. These “place-memory areas” offer a new framework for understanding how the brain implements memory-guided visual behaviors, including navigation

Genetic Characterization of Zika Virus Strains: Geographic Expansion of the Asian Lineage

Zika virus (ZIKV) is a mosquito-transmitted flavivirus found in both Africa and Asia. Human infection with the virus may result in a febrile illness similar to dengue fever and many other tropical infections found in these regions. Previously, little was known about the genetic relationships between ZIKV strains collected in Africa and those collected in Asia. In addition, the geographic origins of the strains responsible for the recent outbreak of human disease on Yap Island, Federated States of Micronesia, and a human case of ZIKV infection in Cambodia were unknown. Our results indicate that there are two geographically distinct lineages of ZIKV (African and Asian). The virus has circulated in Southeast Asia for at least the past 50 years, whereupon it was introduced to Yap Island resulting in an epidemic of human disease in 2007, and in 2010 was the cause of a pediatric case of ZIKV infection in Cambodia. This study also highlights the danger of ZIKV introduction into new areas and the potential for future epidemics of human disease