865 resultados para Pseudo-population bootstrap approach
Resumo:
The goal of this study is the analysis of the dynamical properties of financial data series from worldwide stock market indices. We analyze the Dow Jones Industrial Average ( ∧ DJI) and the NASDAQ Composite ( ∧ IXIC) indexes at a daily time horizon. The methods and algorithms that have been explored for description of physical phenomena become an effective background, and even inspiration, for very productive methods used in the analysis of economical data. We start by applying the classical concepts of signal analysis, Fourier transform, and methods of fractional calculus. In a second phase we adopt a pseudo phase plane approach.
Resumo:
El objetivo de este capítulo es mostrar los resultados de investigación del desempeño de las redes de servicios de salud frente a diferentes dimensiones relacionadas al acceso, coordinación y calidad de la atención en dos enfermedades crónicas como es el cáncer de mama y la diabetes en Colombia, importantes patologías por su incidencia e impacto así como por la necesidad de la mecanismos efectivos de coordinación para la adecuada atención de los usuarios del sistema de salud. Por tanto, se realiza el análisis del desempeño de dos redes de servicios de salud en la atención de usuarias con diagnostico confirmado de cáncer de mama, vinculadas unas a redes pertenecientes al régimen contributivo y otras al régimen subsidiado. Redes que también fueron consideradas para el análisis del desempeño en la atención de usuarios con diagnostico confirmado de diabetes, en el que de manera adicional participó otra red perteneciente al régimen subsidiado con área de operación en el municipio de Soacha, puesto que las dos anteriores tiene influencia en la ciudad de Bogotá. La fuente primaria de los datos fue la historia clínica y éstos fueron extraídos de acuerdo a ciertos indicadores seleccionados por el equipo investigador a través de un previo proceso de validación y a partir de su importancia para evidenciar el desempeño de las redes de servicios de salud en las dimensiones enunciadas anteriormente. Se muestran los resultados del estudio, a partir de los cuales se propone una breve discusión y conclusiones.
Resumo:
A new macroporous stationary phase bearing 'tweezer' receptors that exhibit specificity for cholesterol has been constructed from rigid multifunctional vinylic monomers derived from 3,5-dibromobenzoic acid, propargyl alcohol and cholesterol. The synthesis of the novel tweezer monomer that contains two cholesterol receptor arms using palladium mediated Sonogashira methodologies and carbonate couplings is reported. The subsequent co-polymerisation of this tweezer monomer with a range of cross-linking agents via a 'pseudo' molecular imprinting approach afforded a diverse set of macroporous materials. The selectivity and efficacy of these materials for cholesterol binding was assessed using a chromatographic screening process. The optimum macroporous stationary phase material composition was subsequently used to construct monolithic solid phase extraction columns for use in the selective extraction of cholesterol from multi-component mixtures of structurally related steroids.
Resumo:
Background Staphylococcus aureus is a major cause of healthcare associated mortality, but like many important bacterial pathogens, it is a common constituent of the normal human body flora. Around a third of healthy adults are carriers. Recent evidence suggests that evolution of S. aureus during nasal carriage may be associated with progression to invasive disease. However, a more detailed understanding of within-host evolution under natural conditions is required to appreciate the evolutionary and mechanistic reasons why commensal bacteria such as S. aureus cause disease. Therefore we examined in detail the evolutionary dynamics of normal, asymptomatic carriage. Sequencing a total of 131 genomes across 13 singly colonized hosts using the Illumina platform, we investigated diversity, selection, population dynamics and transmission during the short-term evolution of S. aureus. Principal Findings We characterized the processes by which the raw material for evolution is generated: micro-mutation (point mutation and small insertions/deletions), macro-mutation (large insertions/deletions) and the loss or acquisition of mobile elements (plasmids and bacteriophages). Through an analysis of synonymous, non-synonymous and intergenic mutations we discovered a fitness landscape dominated by purifying selection, with rare examples of adaptive change in genes encoding surface-anchored proteins and an enterotoxin. We found evidence for dramatic, hundred-fold fluctuations in the size of the within-host population over time, which we related to the cycle of colonization and clearance. Using a newly-developed population genetics approach to detect recent transmission among hosts, we revealed evidence for recent transmission between some of our subjects, including a husband and wife both carrying populations of methicillin-resistant S. aureus (MRSA). Significance This investigation begins to paint a picture of the within-host evolution of an important bacterial pathogen during its prevailing natural state, asymptomatic carriage. These results also have wider significance as a benchmark for future systematic studies of evolution during invasive S. aureus disease.
Resumo:
O objetivo deste trabalho foi investigar a produção científica sobre Plantão Psicológico no Brasil, entre 1997 e 2009, através de pesquisa em bases eletrônicas de dados científicos, utilizando o descritor "plantão psicológico". Obtiveram-se 38 resumos, analisados a partir das seguintes categorias: distribuição, autoria, filiação institucional, fonte, ano, suporte de publicação, população alvo, enfoque teórico, natureza do trabalho e região geográfica do país. Os resultados sugerem que as bases eletrônicas de dados constituem atualmente importante fonte de acesso à produção brasileira sobre Plantão Psicológico. Verifica-se uma prevalência na produção sobre o assunto na Região Sudeste, assim como na utilização da Abordagem Centrada na Pessoa, revelando maior ênfase em pesquisa relacionada à dissertação, com predominância de produção em 2005 e 2006.
Resumo:
We use data from about 700 GPS stations in the EuroMediterranen region to investigate the present-day behavior of the the Calabrian subduction zone within the Mediterranean-scale plates kinematics and to perform local scale studies about the strain accumulation on active structures. We focus attenction on the Messina Straits and Crati Valley faults where GPS data show extentional velocity gradients of ∼3 mm/yr and ∼2 mm/yr, respectively. We use dislocation model and a non-linear constrained optimization algorithm to invert for fault geometric parameters and slip-rates and evaluate the associated uncertainties adopting a bootstrap approach. Our analysis suggest the presence of two partially locked normal faults. To investigate the impact of elastic strain contributes from other nearby active faults onto the observed velocity gradient we use a block modeling approach. Our models show that the inferred slip-rates on the two analyzed structures are strongly impacted by the assumed locking width of the Calabrian subduction thrust. In order to frame the observed local deformation features within the present- day central Mediterranean kinematics we realyze a statistical analysis testing the indipendent motion (w.r.t. the African and Eurasias plates) of the Adriatic, Cal- abrian and Sicilian blocks. Our preferred model confirms a microplate like behaviour for all the investigated blocks. Within these kinematic boundary conditions we fur- ther investigate the Calabrian Slab interface geometry using a combined approach of block modeling and χ2ν statistic. Almost no information is obtained using only the horizontal GPS velocities that prove to be a not sufficient dataset for a multi-parametric inversion approach. Trying to stronger constrain the slab geometry we estimate the predicted vertical velocities performing suites of forward models of elastic dislocations varying the fault locking depth. Comparison with the observed field suggest a maximum resolved locking depth of 25 km.
Resumo:
The mechanism underlying the mineralization of bone is well studied and yet it remains controversial. Inherent difficulties of imaging mineralized tissues and the aqueous solubility of calcium and phosphate, the 2 ions which combine to form bone mineral crystals, limit current analyses of labile diffusible, amorphous, and crystalline intermediates by electron microscopy. To improve the retention of calcium and phosphorus, we developed a pseudo nonaqueous processing approach and used it to characterize biomineralization foci, extracellular sites of hydroxyapatite deposition in osteoblastic cell cultures. Since mineralization of UMR106-01 osteoblasts is temporally synchronized and begins 78 h after plating, we used these cultures to evaluate the effectiveness of our method when applied to cells just prior to the formation of the first mineral crystals. Our approach combines for the first time 3 well-established methods with a fourth one, i.e. dry ultrathin sectioning. Dry ultrathin sectioning with an oscillating diamond knife was used to produce electron spectroscopic images of mineralized biomineralization foci which were high-pressure frozen and freeze substituted. For comparison, cultures were also treated with conventional processing and wet sectioning. The results show that only the use of pseudo nonaqueous processing was able to detect extracellular sites of early calcium and phosphorus enrichment at 76 h, several hours prior to detection of mineral crystals within biomineralization foci.
Resumo:
BACKGROUND: Opportunistic screening for genital chlamydia infection is being introduced in England, but evidence for the effectiveness of this approach is lacking. There are insufficient data about young peoples' use of primary care services to determine the potential coverage of opportunistic screening in comparison with a systematic population-based approach. AIM: To estimate use of primary care services by young men and women; to compare potential coverage of opportunistic chlamydia screening with a systematic postal approach. DESIGN OF STUDY: Population based cross-sectional study. SETTING: Twenty-seven general practices around Bristol and Birmingham. METHOD: A random sample of patients aged 16-24 years were posted a chlamydia screening pack. We collected details of face-to-face consultations from general practice records. Survival and person-time methods were used to estimate the cumulative probability of attending general practice in 1 year and the coverage achieved by opportunistic and systematic postal chlamydia screening. RESULTS: Of 12 973 eligible patients, an estimated 60.4% (95% confidence interval [CI] = 58.3 to 62.5%) of men and 75.3% (73.7 to 76.9%) of women aged 16-24 years attended their practice at least once in a 1-year period. During this period, an estimated 21.3% of patients would not attend their general practice but would be reached by postal screening, 9.2% would not receive a postal invitation but would attend their practice, and 11.8% would be missed by both methods. CONCLUSIONS: Opportunistic and population-based approaches to chlamydia screening would both fail to contact a substantial minority of the target group, if used alone. A pragmatic approach combining both strategies might achieve higher coverage.
Resumo:
Mobile Mesh Network based In-Transit Visibility (MMN-ITV) system facilitates global real-time tracking capability for the logistics system. In-transit containers form a multi-hop mesh network to forward the tracking information to the nearby sinks, which further deliver the information to the remote control center via satellite. The fundamental challenge to the MMN-ITV system is the energy constraint of the battery-operated containers. Coupled with the unique mobility pattern, cross-MMN behavior, and the large-spanned area, it is necessary to investigate the energy-efficient communication of the MMN-ITV system thoroughly. First of all, this dissertation models the energy-efficient routing under the unique pattern of the cross-MMN behavior. A new modeling approach, pseudo-dynamic modeling approach, is proposed to measure the energy-efficiency of the routing methods in the presence of the cross-MMN behavior. With this approach, it could be identified that the shortest-path routing and the load-balanced routing is energy-efficient in mobile networks and static networks respectively. For the MMN-ITV system with both mobile and static MMNs, an energy-efficient routing method, energy-threshold routing, is proposed to achieve the best tradeoff between them. Secondly, due to the cross-MMN behavior, neighbor discovery is executed frequently to help the new containers join the MMN, hence, consumes similar amount of energy as that of the data communication. By exploiting the unique pattern of the cross-MMN behavior, this dissertation proposes energy-efficient neighbor discovery wakeup schedules to save up to 60% of the energy for neighbor discovery. Vehicular Ad Hoc Networks (VANETs)-based inter-vehicle communications is by now growingly believed to enhance traffic safety and transportation management with low cost. The end-to-end delay is critical for the time-sensitive safety applications in VANETs, and can be a decisive performance metric for VANETs. This dissertation presents a complete analytical model to evaluate the end-to-end delay against the transmission range and the packet arrival rate. This model illustrates a significant end-to-end delay increase from non-saturated networks to saturated networks. It hence suggests that the distributed power control and admission control protocols for VANETs should aim at improving the real-time capacity (the maximum packet generation rate without causing saturation), instead of the delay itself. Based on the above model, it could be determined that adopting uniform transmission range for every vehicle may hinder the delay performance improvement, since it does not allow the coexistence of the short path length and the low interference. Clusters are proposed to configure non-uniform transmission range for the vehicles. Analysis and simulation confirm that such configuration can enhance the real-time capacity. In addition, it provides an improved trade off between the end-to-end delay and the network capacity. A distributed clustering protocol with minimum message overhead is proposed, which achieves low convergence time.
Resumo:
BACKGROUND Vitamin D deficiency is prevalent in HIV-infected individuals and vitamin D supplementation is proposed according to standard care. This study aimed at characterizing the kinetics of 25(OH)D in a cohort of HIV-infected individuals of European ancestry to better define the influence of genetic and non-genetic factors on 25(OH)D levels. These data were used for the optimization of vitamin D supplementation in order to reach therapeutic targets. METHODS 1,397 25(OH)D plasma levels and relevant clinical information were collected in 664 participants during medical routine follow up visits. They were genotyped for 7 SNPs in 4 genes known to be associated with 25(OH)D levels. 25(OH)D concentrations were analyzed using a population pharmacokinetic approach. The percentage of individuals with 25(OH)D concentrations within the recommended range of 20-40ng/ml during 12 months of follow up and several dosage regimens were evaluated by simulation. RESULTS A one-compartment model with linear absorption and elimination was used to describe 25(OH)D pharmacokinetics, while integrating endogenous baseline plasma concentrations. Covariate analyses confirmed the effect of seasonality, body mass index, smoking habits, the analytical method, darunavir/r and the genetic variant in GC (rs2282679) on 25(OH)D concentrations. 11% of the interindividual variability in 25(OH)D levels was explained by seasonality and other non-genetic covariates and 1% by genetics. The optimal supplementation for severe vitamin D deficient patients was 300000 IU two times per year. CONCLUSIONS This analysis allowed identifying factors associated with 25(OH)D plasma levels in HIV-infected individuals. Improvement of dosage regimen and timing of vitamin D supplementation is proposed based on those results.
Resumo:
My dissertation focuses on developing methods for gene-gene/environment interactions and imprinting effect detections for human complex diseases and quantitative traits. It includes three sections: (1) generalizing the Natural and Orthogonal interaction (NOIA) model for the coding technique originally developed for gene-gene (GxG) interaction and also to reduced models; (2) developing a novel statistical approach that allows for modeling gene-environment (GxE) interactions influencing disease risk, and (3) developing a statistical approach for modeling genetic variants displaying parent-of-origin effects (POEs), such as imprinting. In the past decade, genetic researchers have identified a large number of causal variants for human genetic diseases and traits by single-locus analysis, and interaction has now become a hot topic in the effort to search for the complex network between multiple genes or environmental exposures contributing to the outcome. Epistasis, also known as gene-gene interaction is the departure from additive genetic effects from several genes to a trait, which means that the same alleles of one gene could display different genetic effects under different genetic backgrounds. In this study, we propose to implement the NOIA model for association studies along with interaction for human complex traits and diseases. We compare the performance of the new statistical models we developed and the usual functional model by both simulation study and real data analysis. Both simulation and real data analysis revealed higher power of the NOIA GxG interaction model for detecting both main genetic effects and interaction effects. Through application on a melanoma dataset, we confirmed the previously identified significant regions for melanoma risk at 15q13.1, 16q24.3 and 9p21.3. We also identified potential interactions with these significant regions that contribute to melanoma risk. Based on the NOIA model, we developed a novel statistical approach that allows us to model effects from a genetic factor and binary environmental exposure that are jointly influencing disease risk. Both simulation and real data analyses revealed higher power of the NOIA model for detecting both main genetic effects and interaction effects for both quantitative and binary traits. We also found that estimates of the parameters from logistic regression for binary traits are no longer statistically uncorrelated under the alternative model when there is an association. Applying our novel approach to a lung cancer dataset, we confirmed four SNPs in 5p15 and 15q25 region to be significantly associated with lung cancer risk in Caucasians population: rs2736100, rs402710, rs16969968 and rs8034191. We also validated that rs16969968 and rs8034191 in 15q25 region are significantly interacting with smoking in Caucasian population. Our approach identified the potential interactions of SNP rs2256543 in 6p21 with smoking on contributing to lung cancer risk. Genetic imprinting is the most well-known cause for parent-of-origin effect (POE) whereby a gene is differentially expressed depending on the parental origin of the same alleles. Genetic imprinting affects several human disorders, including diabetes, breast cancer, alcoholism, and obesity. This phenomenon has been shown to be important for normal embryonic development in mammals. Traditional association approaches ignore this important genetic phenomenon. In this study, we propose a NOIA framework for a single locus association study that estimates both main allelic effects and POEs. We develop statistical (Stat-POE) and functional (Func-POE) models, and demonstrate conditions for orthogonality of the Stat-POE model. We conducted simulations for both quantitative and qualitative traits to evaluate the performance of the statistical and functional models with different levels of POEs. Our results showed that the newly proposed Stat-POE model, which ensures orthogonality of variance components if Hardy-Weinberg Equilibrium (HWE) or equal minor and major allele frequencies is satisfied, had greater power for detecting the main allelic additive effect than a Func-POE model, which codes according to allelic substitutions, for both quantitative and qualitative traits. The power for detecting the POE was the same for the Stat-POE and Func-POE models under HWE for quantitative traits.
Resumo:
Most Rhizobium leguminosarum bv. viciae isolates are able to specifically nodulate plants of any of four different legume genera: Pisum, Lens, Vicia, and Lathyrus. However, previous evidence suggests that some genotypes are more adapted to a given plant host than others, and that the plant host can select specific genotypes among those present in a given soil population. We have used a population genomics approach to confirm that this is indeed the case, and to analyze the specific genotypic characteristics that each plant host selects
Resumo:
Determining the dimensionality of G provides an important perspective on the genetic basis of a multivariate suite of traits. Since the introduction of Fisher's geometric model, the number of genetically independent traits underlying a set of functionally related phenotypic traits has been recognized as an important factor influencing the response to selection. Here, we show how the effective dimensionality of G can be established, using a method for the determination of the dimensionality of the effect space from a multivariate general linear model introduced by AMEMIYA (1985). We compare this approach with two other available methods, factor-analytic modeling and bootstrapping, using a half-sib experiment that estimated G for eight cuticular hydrocarbons of Drosophila serrata. In our example, eight pheromone traits were shown to be adequately represented by only two underlying genetic dimensions by Amemiya's approach and factor-analytic modeling of the covariance structure at the sire level. In, contrast, bootstrapping identified four dimensions with significant genetic variance. A simulation study indicated that while the performance of Amemiya's method was more sensitive to power constraints, it performed as well or better than factor-analytic modeling in correctly identifying the original genetic dimensions at moderate to high levels of heritability. The bootstrap approach consistently overestimated the number of dimensions in all cases and performed less well than Amemiya's method at subspace recovery.
Resumo:
2010 Mathematics Subject Classification: 62J99.
Resumo:
El presente artículo propone el análisis de la composición socio-demográfica del territorio de Misiones a partir de los resultados del censo específico de territorios nacionales de 1920. Este análisis abordará tanto los resultados de este censo, como sus condiciones de producción y los objetivos políticos que inspiraron su realización. A través de este análisis se buscará, en primer lugar, abordar la realización de este censo como parte de la agenda de ampliación de derechos políticos del gobierno radical de la Argentina. En segundo lugar, conocer las características generales de la población de Misiones, en cuanto a su composición según sexo, edades y origen. En tercer lugar, observar las características poblacionales en las zonas fronterizas del territorio. El objetivo será aportar al conocimiento socio-demográfico de Misiones, en tanto permite observar las particularidades en la composición poblacional de las zonas fronterizas que constituyeron los escenarios de un conjunto de movimientos políticos de carácter transfronterizo entre las décadas de 1920 y 1930.