Simplicial Complexes From Graphs Toward Graph Persistence

Persistent homology is a branch of computational topology which uses geometry and topology for shape description and analysis. This dissertation is an introductory study to link persistent homology and graph theory, the connection being represented by various methods to build simplicial complexes from a graph. The methods we consider are the complex of cliques, of independent sets, of neighbours, of enclaveless sets and complexes from acyclic subgraphs, each revealing several properties of the underlying graph. Moreover, we apply the core ideas of persistence theory in the new context of graph theory, we define the persistent block number and the persistent edge-block number

Uso de habitat y residencia de la tortuga verde (Chelonia mydas) en dos baías diferentes de la Isla San Cristóbal.

The Green turtle, Chelonia Mydas, is the most common specie of the Archipelago, where some potential nesting beaches can be found in Santa Cruz, Baltra and Isabela. The great majority of studies made in turtles focused on nesting populations. There are few studies in the water, one of them focuses on habitat utilization by juvenile hawksbill turtles (Eretmochelys imbricata), in a shallow water coral reef in the Seychelles in the Indian Ocean This study started from the month of October of the 2008 to October of the 2009, where the presence and behavior of the green turtle was analyzed in two different bays on San Cristobal Island (The Lobería and Punta Carola). Lobería, is located in the south of the Island, a very productive zone, where it could be found are greater diversity of seaweed, in the case of Punta Carola it is affected by human actions (impact of traffic boat and sewage waters of the town). The two bays the Lobería and Punta Carola are of the most accessible beaches of the island, and therefore the most visited ones. In these two areas during the whole year green turtles are present while the nesting activity in theses beaches is sporadic. This study investigates the different habitat uses of the turtles and implements a new method, indentifying different individuals by combinations of natural marks in their carapace. This method helps providing more information about their residency and movements in the two areas. The relative abundance of turtles differs between the two bays being the highest Lobería, and the same happens with the residence of individuals. In habitat utilization predominate the feeding and resting in the two areas.La tortuga Verde, Chelonia Mydas, es la más común del Archipiélago de Galápagos, zona donde se pueden encontrar algunas playas potenciales de anidación como Santa Cruz, Baltra e Isabela. La gran mayoría de los estudios realizados en tortugas se han enfocado en poblaciones anidadoras. Se han efectuado muy pocos estudios en el agua, uno de ellos enfocado en el uso del hábitat de tortugas carey (Eretmochelys imbricata), en aguas poco profundas en las Seychelles en el océano índigo. Este estudio se inicio en el mes de Octubre del 2008 y se extendió hasta Octubre del 2009. Se ha analizado la presencia y el comportamiento de la tortuga verde en dos bahías diferentes aunque cercanas en la Isla San Cristóbal (La Lobería y Punta Carola). La lobería, está localizada al sur de la Isla, en un zona muy productiva, con una gran diversidad de algas, en el caso de Punta Carola en cambio estaa más afectada acciones humanas (tráfico de lanchas y aguas negras del pueblo). Las dos bahías, La Lobería y Punta Carola, son playas que por ser las más accesibles de las islas son también las hace las más visitadas . En estas dos áreas se observa la presencia de la tortuga verde, durante todo el año, mientras que la anidación en estas playas es esporádica. Este estudio se centra en investigar el uso de hábitat y también en identificar individuos por medio de combinaciones de marcas naturales en su caparazón, lo cual ayuda a poder obtener más información sobre su tiempo de residencia en las dos zonas de estudio y patrones de distribución. La abundancia relativa de individuos encontrados difiere entre las dos bahías siendo en la Lobería la más alta, al igual que la residencia de individuos. Los comportamientos predominantes en el uso de hábitat son la alimentación y el descanso en las dos áreas

Beyond topological persistence: Starting from networks

Persistent homology enables fast and computable comparison of topological objects. However, it is naturally limited to the analysis of topological spaces. We extend the theory of persistence, by guaranteeing robustness and computability to significant data types as simple graphs and quivers. We focus on categorical persistence functions that allow us to study in full generality strong kinds of connectedness such as clique communities, $k$-vertex and $k$-edge connectedness directly on simple graphs and monic coherent categories.Comment: arXiv admin note: text overlap with arXiv:1707.0967

On the Preparation of High School Mathematics Teachers

In this paper I discuss some results got in 1997/98 with Brazilian mathematics school teachers. The research was done to investigate their mathematical language as related to the concept of function. A dichotomy was detected between “formal” and “practical” language they used to express their own conceptions of function, as well as to teach their students this subject. Also, I found teachers’ conceptual images “shrinking” as soon as they were far from their colleges or universities programs

β decay of odd-A As to Ge isotopes in the interacting boson-fermion model

The structure of odd-mass isotopes of As and Ge is described in the framework of the proton-neutron interacting boson-fermion model. The energy levels and the electromagnetic properties of 69, 71, 73As and 69, 71, 73Ge are calculated and compared with the experiment. The beta-decay rates from the As isotopes to the Ge isotopes are calculated. The calculated decays tend to be stronger than the observed ones. This may indicate a mixture of components outside the model space in the wave functions of actual nuclei. The effect of the higher-order terms in the decay operators seems small

Comment augmenter l’impact économique du tourisme d’affaires dans le Canton de Neuchâtel?

Le Canton de Neuchâtel est réputé pour son industrie horlogère et microtechnique. En revanche, le tourisme, et plus particulièrement le tourisme d’affaires, n’est pas reconnu comme étant un élément important pour son économie. C’est pourquoi, ce travail s’intéresse aux améliorations pouvant augmenter l’impact économique du tourisme d’affaires dans cette région. Pour cela, une recherche bibliographique et différents entretiens ont été menés. De plus, un atelier a été organisé au Swiss Creative Center et un questionnaire a été envoyé à plusieurs hôteliers du Canton de Neuchâtel. Ce travail se divise en trois parties : une première partie théorique s’intéresse au secteur du tourisme d’affaires et aux impacts économiques de ce dernier. Ensuite, plusieurs éléments liés à ce segment ont été répertoriés, tels que les hôtels et les salles de conférences du Canton. Finalement, plusieurs propositions ont été amenées. Il en résulte que le secteur du tourisme d’affaires n’est que très peu connu dans la région (de même que son impact économique) et que, par conséquent, peu d’actions sont menées afin de le développer. C’est pourquoi, il serait intéressant d’effectuer une étude sectorielle qui permettrait de déterminer l’impact économique de ce secteur dans le Canton. De plus, il conviendrait de revoir le lien entre Neuchâtel Tourisme et Jura & Trois-Lacs (société de marketing pour la région Trois-Lacs) afin d’éviter que Neuchâtel soit désavantagé dans ce regroupement

β decay of the even-even 124Ba nucleus: A test for the interacting boson-fermion-fermion model

IBFFM is applied to β decay of 124Ba to 124Cs. The interacting boson-fermion-fermion model approach to β decay is applied to the decay from the even-even 124Ba to the odd-odd 124Cs nucleus. The theoretical results for energy levels, electromagnetic properties and β decay rates are compared with experimental data for 124Cs. The calculated β-decay rates demonstrate that the interacting boson approximation can be applied in the description of β decays from even-even to odd-odd nuclei

β decay of odd-A Cs isotopes in the interacting boson-fermion model

The structure of odd-mass isotopes of Cs and Xe is described in the framework of IBFM. The model provides a consistent description of beta decay from Cs to Xe nuclei of mass number A = 125, 127, and 129

The Role Of Oxidative Stress In The Pathogenesis Of Epithelial Ovarian Cancer

Ovarian cancer is the leading cause of death from gynecologic malignancies yet the underlying pathophysiology is not clearly established. The disease is usually diagnosed in the advanced stage and carries a poor prognosis. The 5-year survival rate is greater than 75% if diagnosis of the cancer occurs at an early stage; however, this rate drops to 20% when the tumor has spread beyond its origin. Thus, a method for early detection is critically needed, which can help prolong, or even save lives. Currently, an effective screening test for ovarian cancer is lacking. Many tests have been evaluated but have been found to be lacking in sensitivity, specificity, or both. This becomes even more difficult as ovarian cancer is so rare in the general population, with an estimated prevalence of 0.04%. To date, 96% is the highest sensitivity recorded for the early detection of ovarian cancer. However, because of the low prevalence of ovarian cancer, a sensitivity and specificity of 96% would only detect 1 case of cancer per 100 oophorectomies done for positive screens due to the high false positive rate. Clinical and epidemiological investigations have provided evidence supporting the role of reactive oxygen species (ROS) in the prognosis and metastasis of cancer due to exogenous factors that lead to chronic inflammation. In addition, cancer cells are frequently under persistent oxidative stress, which participates in cancer progression as well as in the selection of resistant cells that are unable to be eliminated by apoptosis. A recent novel finding from our laboratory has shown that myeloperoxidase (MPO) is expressed in ovarian cancer cell lines and tissues, with minimal or no expression detected in normal ovarian tissues. Myeloperoxidase is an abundant heme protein, which plays a central role in the formation of reactive oxidant and free radical species. Additionally, under conditions of oxidative stress, MPO serves as a source of free iron. Another source of ROS is the superoxide producing nicotinamide adenine dinucleotide phosphate (NAD(P)H) oxidase, which we observed to be upregulated in ovarian cancer as compared to normal ovarian tissues. It has been reported that mutations in specific regions of NAD(P)H oxidase subunits contribute to the enhancement of the enzyme activity with subsequent increase in superoxide (O2 ●−) production, contributing to enhanced levels of oxidative stress. Therefore, there is compelling eveidence to support the role of oxidative stress in the pathogenesis of ovarian cancer, yet the mechanisms responsible for the dissemination of EOC are not fully understood. The objective of this work is to identify mechanisms of oxidative stress in the pathogenesis of ovarian cancer. The central hypothesis of this study is that ovarian cancer is controlled by mechanisms that emanate from an altered redox balance. To test this hypothesis, the following specific aims have been investigated: Specific Aim I: Determine the oxidative stress profile in epithelial ovarian cancer and determine the effect of the modulation of specific key players of oxidative stress on the persistence of the oncogeneic phenotype. To determine the oxidative stress profile, the expression of the following markers will be evaluated: NAD(P)H oxidase, nitrate/nitrite, glutathione, glutathione reductase, glutathione peroxidase, glutathione s-transferase, inducible nitric oxide synthase, myeloperoxidase, catalase, and superoxide dismutase in epithelial ovarian cancer cells and tissues as compared to their normal counterparts. These markers were selected based on extensive preliminary and published results, utilizing a cell culture model and ovarian cancer tissues. Modulation of key players of oxidative stress will contribute to delineation of the mechanisms of development of ovarian cancer. To achieve this, a combination of knockdown or inhibition of specific pro-oxidants ulizing siRNA or direct inhibition will be performed followed by the assessment of the expression other pro-oxidants as well as the effect on apoptosis. Specific Aim II: To assess the effectiveness of MPO and free iron levels in detection of early stage ovarian cancer. The mechanism by which MPO functions under oxidative stress is not well defined. MPO has been indicated to serve as a source of free iron under oxidative stress. The hypothesis of this aim is that serum MPO and free iron levels can be utilized to distinguish patients with stage I ovarian cancer from those with normal ovaries or benign gynecologic conditions as well as from late state ovarian cancer. MPO and free iron levels will be measured in the sera and tissues of women at the time of ovarian cancer diagnosis as compared to healthy women or those with benign gynecologic disorders respectively. The biological significance of the relationship between serum MPO and free iron, in conjunction with the poor prognosis of ovarian cancer has the potential for future clinical applications. . Specific Aim III: To assess whether a SNP in NAD(P)H oxidase is associated with increased risk of development of ovarian cancer. Single nucleotide polymorphisms (SNPs) are associated with increased risk of several cancers. We evaluated the association of a SNP (rs4673) in the CYBA gene, encoding the p22phox subunit of NAD(P)H oxidase, substituting allele C with T at position 242 located on chromosome 16q24, in high-risk individuals with or without ovarian cancer, with or without a deleterious BRCA1/2 mutation. This SNP is known to be associated an increased activity of the enzyme, resulting in an increase in superoxide production. TaqMan® SNP Genotype analysis and the QuantStudio 12K Flex Real-Time PCR System were utilized to determine the frequency of this SNP in individuals with ovarian cancer as compared to noncancer individuals