Gerência da largura de banda para garantir QoS adaptável em redes sem fio ad hoc

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico.As redes sem fio apresentam um novo paradigma computacional que tem como função principal prover aos usuários o acesso permanente à rede independente de sua localização física. Com a diminuição dos custos dos dispositivos portáteis e o aumento da sua capacidade surgiu um novo conceito chamado redes ad hoc, onde a comunicação é feita diretamente entre os computadores móveis. Neste trabalho são descritas as características fundamentais das redes ad hoc. Assim como as principais tendências para garantir a qualidade de serviço nas redes sem fio, considerando as características: transmissão pouco confiável, largura de banda limitada e alta taxa de erros. No trabalho é proposto um mecanismo para manter QoS adaptável sobre o princípio de gerência da largura de banda em redes sem fio de topologia ad hoc. Também foi desenvolvido um software que permite simular ambientes de redes ad hoc, fazendo as conexões em conformidade com o critério do mecanismo proposto. Para a validação realizaram-se várias experiências que permitiram provar as vantagens do mecanismo. Naquelas redes onde o mecanismo de QoS adaptável foi usado, obteve-se melhor aproveitamento do canal de transmissão, ao mesmo tempo que maior quantidade de conexões eram aceitas

Estudio de caso de un enlace de red inalambrico en una zona rural. propuesta de conexion para entidades agropecuarias

En este trabajo se realiza el estudio de una red inalámbrica de área local WLAN que utiliza el estándar IEEE 802.11 con topología de Enlace LAN, para dar servicios de Internet a la red del Instituto de Ciencia Animal, de Cuba, que es una entidad agropecuaria ubicado en una zona rural. A través de este enlace se resuelve uno de los principales problemas que presenta el sector agropecuario, que es la falta de comunicación entre los productores, investigadores y profesores pues, de forma general, sus entidades se encuentran ubicadas en zonas carentes de infraestructura de telecomunicaciones. Para elestudio del enlace se utilizaron varios software y variables a través del protocolo SNMP (Simple Network Management Protocol), así como del software de configuración del equipo, y se definieron diferentes condiciones ambientales y de tráfico de datos. Como resultado se obtuvo que las condiciones ambientales influyen en el Indicador de ruido por subcanales de frecuencia, pero que de forma general no afecta el funcionamiento de la red, por lo que resulta viable la utilización de esta tecnología para el enlace de entidades agropecuarias en zonas rurales. Al mismo tiempo se hace referencia al uso potencial de la tecnología de comunicación por líneas eléctricas (PLC) como alternativa a utilizar para la conexión de estas entidades de forma independiente o conjuntamente con las WLAN

Toward the Discovery of Biological Functions Associated with the Mechanosensor Mtl1p of \u3ci\u3eSaccharomyces cerevisiae\u3c/i\u3e via Integrative Multi-OMICs Analysis

Functional analysis of the Mtl1 protein in Saccharomyces cerevisiae has revealed that this transmembrane sensor endows yeast cells with resistance to oxidative stress through a signaling mechanism called the cell wall integrity pathway (CWI). We observed upregulation of multiple heat shock proteins (HSPs), proteins associated with the formation of stress granules, and the phosphatase subunit of trehalose 6-phosphate synthase which suggests that mtl1Δ strains undergo intrinsic activation of a non-lethal heat stress response. Furthermore, quantitative global proteomic analysis conducted on TMT-labeled proteins combined with metabolome analysis revealed that mtl1Δ strains exhibit decreased levels of metabolites of carboxylic acid metabolism, decreased expression of anabolic enzymes and increased expression of catabolic enzymes involved in the metabolism of amino acids, with enhanced expression of mitochondrial respirasome proteins. These observations support the idea that Mtl1 protein controls the suppression of a non-lethal heat stress response under normal conditions while it plays an important role in metabolic regulatory mechanisms linked to TORC1 signaling that are required to maintain cellular homeostasis and optimal mitochondrial function

DNA methylation, deamination, and translesion synthesis combine to generate footprint mutations in cancer driver genes in B-cell derived lymphomas and other cancers

Cancer genomes harbor numerous genomic alterations and many cancers accumulate thousands of nucleotide sequence variations. A prominent fraction of these mutations arises as a consequence of the off-target activity of DNA/RNA editing cytosine deaminases followed by the replication/repair of edited sites by DNA polymerases (pol), as deduced from the analysis of the DNA sequence context of mutations in different tumor tissues. We have used the weight matrix (sequence profile) approach to analyze mutagenesis due to Activation Induced Deaminase (AID) and two error-prone DNA polymerases. Control experiments using shuffled weight matrices and somatic mutations in immunoglobulin genes confirmed the power of this method. Analysis of somatic mutations in various cancers suggested that AID and DNA polymerases η and θ contribute to mutagenesis in contexts that almost universally correlate with the context of mutations in A:T and G:C sites during the affinity maturation of immunoglobulin genes. Previously, we demonstrated that AID contributes to mutagenesis in (de)methylated genomic DNA in various cancers. Our current analysis of methylation data from malignant lymphomas suggests that driver genes are subject to different (de)methylation processes than non-driver genes and, in addition to AID, the activity of pols η and θ contributes to the establishment of methylation-dependent mutation profiles. This may reflect the functional importance of interplay between mutagenesis in cancer and (de)methylation processes in different groups of genes. The resulting changes in CpG methylation levels and chromatin modifications are likely to cause changes in the expression levels of driver genes that may affect cancer initiation and/or progression

Unsupervised machine learning method for indirect estimation of reference intervals for chronic kidney disease in the Puerto Rican population

Abstract Reference intervals (RIs) for clinical laboratory values are extremely important for diagnostics and treatment of patients. However, the determination of these ranges is costly and time-consuming. As a result, often different unverified RIs are used in practice for the same analyte and the same range is used for all patients despite evidence that the values are gender, age, and ethnicity dependent. Moreover, the abnormal flags are rudimentary, merely indicating if a value is within the RI. At the same time, clinical lab data generated in the everyday medical practice contains a wealth of information, that given the correct methodology, can help determine the RIs for each specific segment of the population, including populations that suffer from health disparities. In this work, we develop unsupervised machine learning methods, based on Gaussian mixtures, to determine RIs of analytes related to chronic kidney disease, using millions of routine lab results for the Puerto Rican population. We show that the measures are both gender and age dependent and we find evidence for normal age-related organ function deterioration and failure. We also show that the joint distribution of measures improves the diagnostic value of the lab results

Bibliographie descriptive et critique de la réception canadienne de Bonheur d'occasion (1945-1983)

Dans un premier temps, notre présentation de Bonheur d'occasion fournira des renseignements sur les éditions et les tirages du roman, les prix et les mentions obtenus, les droits cinématographiques. Suivra une perspective générale de l'accueil de la critique au Canada. Dans une troisième partie, nous analyserons l'évolution de l'approche du roman au Canada français. Cette analyse sera mise en parallèle avec l'évolution du contexte idéologique qui entoure l'oeuvre et la critique

Non-Random Enrichment of Single-Nucleotide Polymorphisms Associated with Clopidogrel Resistance within Risk Loci Linked to the Severity of Underlying Cardiovascular Diseases: The Role of Admixture

Cardiovascular disease (CVD) is one of the leading causes of death in Puerto Rico, where clopidogrel is commonly prescribed to prevent ischemic events. Genetic contributors to both a poor clopidogrel response and the severity of CVD have been identified mainly in Europeans. However, the non-random enrichment of single-nucleotide polymorphisms (SNPs) associated with clopidogrel resistance within risk loci linked to underlying CVDs, and the role of admixture, have yet to be tested. This study aimed to assess the possible interaction between genetic biomarkers linked to CVDs and those associated with clopidogrel resistance among admixed Caribbean Hispanics. We identified 50 SNPs significantly associated with CVDs in previous genome-wide association studies (GWASs). These SNPs were combined with another ten SNPs related to clopidogrel resistance in Caribbean Hispanics. We developed Python scripts to determine whether SNPs related to CVDs are in close proximity to those associated with the clopidogrel response. The average and individual local ancestry (LAI) within each locus were inferred, and 60 random SNPs with their corresponding LAIs were generated for enrichment estimation purposes. Our results showed no CVD-linked SNPs in close proximity to those associated with the clopidogrel response among Caribbean Hispanics. Consequently, no genetic loci with a dual predictive role for the risk of CVD severity and clopidogrel resistance were found in this population. Native American ancestry was the most enriched within the risk loci linked to CVDs in this population. The non-random enrichment of disease susceptibility loci with drug-response SNPs is a new frontier in Precision Medicine that needs further attention

Nucleotide weight matrices reveal ubiquitous mutational footprints of AID/APOBEC deaminases in human cancer genomes

Cancer genomes accumulate nucleotide sequence variations that number in the tens of thousands per genome. A prominent fraction of these mutations is thought to arise as a consequence of the off-target activity of DNA/RNA editing cytosine deaminases. These enzymes, collectively called activation induced deaminase (AID)/APOBECs, deaminate cytosines located within defined DNA sequence contexts. The resulting changes of the original C:G pair in these contexts (mutational signatures) provide indirect evidence for the participation of specific cytosine deaminases in a given cancer type. The conventional method used for the analysis of mutable motifs is the consensus approach. Here, for the first time, we have adopted the frequently used weight matrix (sequence profile) approach for the analysis of mutagenesis and provide evidence for this method being a more precise descriptor of mutations than the sequence consensus approach. We confirm that while mutational footprints of APOBEC1, APOBEC3A, APOBEC3B, and APOBEC3G are prominent in many cancers, mutable motifs characteristic of the action of the humoral immune response somatic hypermutation enzyme, AID, are the most widespread feature of somatic mutation spectra attributable to deaminases in cancer genomes. Overall, the weight matrix approach reveals that somatic mutations are significantly associated with at least one AID/APOBEC mutable motif in all studied cancers

Insight on the Genetics of Atrial Fibrillation in Puerto Rican Hispanics

Non-Hispanic whites present with higher atrial fibrillation (AF) prevalence than other racial minorities living in the mainland USA. In two hospital-based studies, Puerto Rican Hispanics had a lower prevalence of atrial fibrillation of 2.5% than non-Hispanic Whites with 5.7%. This data is particularly controversial because Hispanics possess a higher prevalence of traditional risk factors for developing AF yet have a lower AF prevalence. This phenomenon is known as the atrial fibrillation paradox. Despite recent advancements in understanding AF, its pathogenesis remains unclear. In this study, we compared a genetic dataset of Puerto Rican Hispanics to 111 SNP known to be associated with AF in a large European cohort and determine if they are associated with AF susceptibility in our cohort. To achieve this aim, we performed a secondary analysis of existing data using the following two studies: (1) The Pharmacogenetics of Warfarin in Puerto Ricans study and the (2) A Genomic Approach for Clopidogrel in Caribbean Hispanics, and assess for the presence of European SNPs associated with AF from the genome-wide association study of 1 million people identifies 111 loci for atrial fibrillation. We used data from 555 cardiovascular Puerto Rican Hispanic patients, consisting of 486 control and 69 cases. We found that the following SNPs showed significant association with AF in PHR: rs2834618, rs6462079, rs7508, rs2040862, and rs10458660. Some of these SNPs are proteins involved in lysosomal activities responsible for breaking ceramides to sphingosines and collagen deposition around atrial cardiomyocytes. Furthermore, we performed a machine learning analysis and determined that Native American admixture and heart failure were strongly predictive of AF in PHR. For the first time, this study provides some genetic insight into AF’s mechanisms in a Puerto Rican Hispanic cohort