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Search Results: 1 - 10 of 462305 matches for " Wesley DB;Mendon?a "
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Resposta à mosca-branca (Bemisia tabaci) e ao Tomato severe rugose virus de acessos de Solanum subgênero Leptostemonum
Michereff-Filho, Miguel;Machini, Wesley DB;Mendona, José L;Fonseca, Maria Esther de N;Fernandes-Acioli, Niday AN;Boiteux, Leonardo S;
Horticultura Brasileira , 2012, DOI: 10.1590/S0102-05362012000300014
Abstract: the whitefly (bemisia tabaci) and the infection by begomovirus species are two major problems affecting yield and quality of the tomato (solanum lycopersicum) crop as well as other solanaceae species of economic importance. the present work was conducted aiming to characterize the reaction of 36 accessions of the genus solanum subgenus leptostemonum (= spiny solanum species) and closely related species to tomato severe rugose virus (tosrv) and b. tabaci. seedlings of the accessions (43 days after sowing) were exposed under greenhouse conditions to viruliferous whiteflies (b. tabaci biotype b) carrying an isolate of tosrv. two susceptible tomato cultivars were used as susceptible controls. reaction to the virus was evaluated using a symptom severity scale and the systemic tosrv infection was evaluated via pcr with universal begomovirus primers. a group of accessions from s. stramonifolium, s. asperolanatum, and s. jamaiscense displayed mild symptoms and low virus accumulation. the accession s. mammosum 'cnph 035', even though tolerant, was the only one displaying clear tosrv symptoms and conspicuous systemic spread of the virus. the remaining accessions were found to be free of tosrv symptoms and with no indication of systemic infection. this germplasm collection was also evaluated to b. tabaci in a free-choice assay under greenhouse conditions. significant differences were observed for the number of eggs and number of 4th instar nymphs. a group of ten accessions from s. asperolanatum, s. stramonifolium, s. paniculatum, and s. syssimbrifolium displayed no signs of whitefly infestation. therefore, accessions of the subgenus leptostemonum might represent potential sources of resistance genes to both b. tabaci and tosrv. this genetic diversity might be transferred to other solanum species via conventional and/or transgenic approaches. our results also indicated that these spiny solanum species might have minor importance either as reservoirs of begomovirus or as alterna
Interpreting Dose-Response Relation for Exposure to Multiple Sound Impulses in the Framework of Immunity  [PDF]
Hongyun Wang, Wesley A. Burgei, Hong Zhou
Health (Health) , 2017, DOI: 10.4236/health.2017.913132
Abstract: Hearing loss is a common military health problem and it is closely related to exposures to impulse noises from blast explosions and weapon firings. In a study based on test data of chinchillas and scaled to humans (Military Medicine, 181: 59-69), an empirical injury model was constructed for exposure to multiple sound impulses of equal intensity. Building upon the empirical injury model, we conduct a mathematical study of the hearing loss injury caused by multiple impulses of non-uniform intensities. We adopt the theoretical framework of viewing individual sound exposures as separate injury causing events, and in that framework, we examine synergy for causing injury (fatigue) or negative synergy (immunity) or independence among a sequence of doses. Starting with the empirical logistic dose-response relation and the empirical dose combination rule, we show that for causing injury, a sequence of sound exposure events are not independent of each other. The phenomenological effect of a preceding event on the subsequent event is always immunity. We extend the empirical dose combination rule, which is applicable only in the case of homogeneous impulses of equal intensity, to accommodate the general case of multiple heterogeneous sound exposures with non-uniform intensities. In addition to studying and extending the empirical dose combination rule, we also explore the dose combination rule for the hypothetical case of independent events, and compare it with the empirical one. We measure the effect of immunity quantitatively using the immunity factor defined as the percentage of decrease in injury probability attributed to the sound exposure in the preceding event. Our main findings on the immunity factor are: 1) the immunity factor is primarily a function of the difference in SELA (A- weighted sound exposure level) between the two sound exposure events; it is virtually independent of the magnitude of the two SELA values as long as the difference is fixed; 2) the immunity factor increases monotonically from 0 to 100% as the first dose is varied from being significantly below the second dose, to being moderately above the second dose. The extended dose-response formulation developed in this study provides a theoretical framework for assessing the injury risk in realistic situations.
Risk of Hearing Loss Caused by Multiple Acoustic Impulses in the Framework of Biovariability  [PDF]
Hongyun Wang, Wesley A. Burgei, Hong Zhou
Health (Health) , 2018, DOI: 10.4236/health.2018.105048
Abstract: We consider the hearing loss injury among subjects in a crowd with a wide spectrum of individual intrinsic injury probabilities due to biovariability. For multiple acoustic impulses, the observed injury risk of a crowd vs the effective combined dose follows the logistic dose-response relation. The injury risk of a crowd is the average fraction of injured. The injury risk was measured in experiments as follows: each subject is individually exposed to a sequence of acoustic impulses of a given intensity and the injury is recorded; results of multiple individual subjects were assembled into data sets to mimic the response of a crowd. The effective combined dose was adjusted by varying the number of impulses in the sequence. The most prominent feature observed in experiments is that the injury risk of the crowd caused by multiple impulses is significantly less than the value predicted based on assumption that all impulses act independently in causing injury and all subjects in the crowd are statistically identical. Previously, in the case where all subjects are statistically identical (i.e., no biovariability), we interpreted the observed injury risk caused by multiple impulses in terms of the immunity effects of preceding impulses on subsequent impulses. In this study, we focus on the case where all sound exposure events act independently in causing injury regardless of whether one is preceded by another (i.e., no immunity effect). Instead, we explore the possibility of interpreting the observed logistic dose-response relation in the framework of biovariability of the crowd. Here biovariability means that subjects in the crowd have their own individual injury probabilities. That is, some subjects are biologically less or more susceptible to hearing loss injury than others. We derive analytically the distribution of individual injury probability that produces the observed logistic dose-response relation. For several parameter values, we prove that the derived distribution is mathematically a proper density function. We further study the asymptotic approximations for the density function and discuss their significance in practical numerical computation with finite precision arithmetic. Our mathematical analysis implies that the observed logistic dose-response relation can be theoretically explained in the framework of biovariability in the absence of immunity effect.
Asymptotics and Well-Posedness of the Derived Distribution Density in a Study of Biovariability  [PDF]
Hongyun Wang, Wesley A. Burgei, Hong Zhou
Applied Mathematics (AM) , 2018, DOI: 10.4236/am.2018.96046
In our recent work (Wang, Burgei, and Zhou, 2018) we studied the hearing loss injury among subjects in a crowd with a wide spectrum of heterogeneous individual injury susceptibility due to biovariability. The injury risk of a crowd is defined as the average fraction of injured. We examined mathematically the injury risk of a crowd vs the number of acoustic impulses the crowd is exposed to, under the assumption that all impulses act independently in causing injury regardless of whether one is preceded by another. We concluded that the observed dose-response relation can be explained solely on the basis of biovariability in the form of heterogeneous susceptibility. We derived an analytical solution for the distribution density of injury susceptibility, as a power series expansion in terms of scaled log individual non-injury probability. While theoretically the power series converges for all argument values, in practical computations with IEEE double precision, at large argument values, the numerical accuracy of the power series summation is completely wiped out by the accumulation of round-off errors. In this study, we derive a general asymptotic approximation at large argument values, for the distribution density. The combination of the power series and the asymptotics provides a practical numerical tool for computing the distribution density. We then use this tool to verify numerically that the distribution obtained in our previous theoretical study is indeed a proper density. In addition, we will also develop a very efficient and accurate Pade approximation for the distribution density.
Dose-Injury Relation as a Model for Uncertainty Propagation from Input Dose to Target Dose  [PDF]
Hongyun Wang, Wesley A. Burgei, Hong Zhou
American Journal of Operations Research (AJOR) , 2018, DOI: 10.4236/ajor.2018.85021
Abstract: We study a general framework for assessing the injury probability corresponding to an input dose quantity. In many applications, the true value of input dose may not be directly measurable. Instead, the input dose is estimated from measurable/controllable quantities via numerical simulations using assumed representative parameter values. We aim at developing a simple modeling framework for accommodating all uncertainties, including the discrepancy between the estimated input dose and the true input dose. We first interpret the widely used logistic dose-injury model as the result of dose propagation uncertainty from input dose to target dose at the active site for injury where the binary outcome is completely determined by the target dose. We specify the symmetric logistic dose-injury function using two shape parameters: the median injury dose and the 10 - 90 percentile width. We relate the two shape parameters of injury function to the mean and standard deviation of the dose propagation uncertainty. We find 1) a larger total uncertainty will spread more the dose-response function, increasing the 10 - 90 percentile width and 2) a systematic over-estimate of the input dose will shift the injury probability toward the right along the estimated input dose. This framework provides a way of revising an established injury model for a particular test population to predict the injury model for a new population with different distributions of parameters that affect the dose propagation and dose estimation. In addition to modeling dose propagation uncertainty, we propose a new 3-parameter model to include the skewness of injury function. The proposed 3-parameter function form is based on shifted log-normal distribution of dose propagation uncertainty and is approximately invariant when other uncertainties are added. The proposed 3-parameter function form provides a framework for extending skewed injury model from a test population to a target population in application.
Risk of Hearing Loss Injury Caused by Multiple Flash Bangs on a Crowd  [PDF]
Hongyun Wang, Wesley A. Burgei, Hong Zhou
American Journal of Operations Research (AJOR) , 2018, DOI: 10.4236/ajor.2018.84014
Abstract: A flash bang is a non-lethal explosive device that delivers intensely loud bangs and bright lights to suppress potentially dangerous targets. It is usually used in crowd control, hostage rescue and numerous other missions. We construct a model for assessing quantitatively the risk of hearing loss injury caused by multiple flash bangs. The model provides a computational framework for incorporating the effects of the key factors defining the situation and for testing various sub-models for these factors. The proposed model includes 1) uncertainty in the burst point of flash bang mortar, 2) randomness in the dispersion of multiple submunitions after the flash bang mortar burst, 3) decay of acoustic impulse from a single submunition to an individual subject along the ground surface, 4) the effective combined sound exposure level on an individual subject caused by multiple submunitions at various distances from the subject, and 5) randomness in the spatial distribution of subjects in the crowd. With the mathematical model formulated, we seek to characterize the overall effect of flash bang mortar in the form of an effective injury area. We carry out simulations to study the effects of uncertainty and randomness on the risk of hearing loss injury of the crowd. The proposed framework serves as a starting point for a comprehensive assessment of hearing loss injury risk, taking into consideration all realistic and relevant features of flash bang mortar. It also provides a platform for testing and updating component models.
An Approach for Personalized Social Matching Systems by Using Ant Colony  [PDF]
Luziane Ferreira de Mendona
Social Networking (SN) , 2014, DOI: 10.4236/sn.2014.32013

Personalized social matching systems can be seen as recommender systems that recommend people to others in the social networks, with desirable skills/characteristics. In this work, an algorithm based on Ant Colony is proposed to solve the optimization problem of clustering/matching people in a social network specifically designed for this purpose; during this process, their personal characteristics and preferences (and the degree of importance thereof) are taken into account. The numerical results indicate that the proposed algorithm can successfully perform clustering with a variable number of individuals.

Terrestrial, Habitable-Zone Exoplanet Frequency from Kepler
Wesley A. Traub
Physics , 2011, DOI: 10.1088/0004-637X/745/1/20
Abstract: Data from Kepler's first 136 days of operation are analyzed to determine the distribution of exoplanets with respect to radius, period, and host-star spectral type. The analysis is extrapolated to estimate the percentage of terrestrial, habitable-zone exoplanets. The Kepler census is assumed to be complete for bright stars (magnitude <14.0) having transiting planets >0.5 Earth radius and periods <42 days. It is also assumed that the size distribution of planets is independent of orbital period, and that there are no hidden biases in the data. Six significant statistical results are found: there is a paucity of small planet detections around faint target stars, probably an instrumental effect; the frequency of mid-size planet detections is independent of whether the host star is bright or faint; there are significantly fewer planets detected with periods <3 days, compared to longer periods, almost certainly an astrophysical effect; the frequency of all planets in the population with periods <42 days is 29%, broken down as terrestrials 9%, ice giants 18%, and gas giants 3%; the population has a planet frequency with respect to period which follows a power-law relation dN/dP ~ P^{\beta - 1}, with \beta = 0.71 +/- 0.08; and an extrapolation to longer periods gives the frequency of terrestrial planets in the habitable zones of FGK stars as \eta_\oplus = (34 +/- 14)%. Thus about one-third of FGK stars are predicted to have at least one terrestrial, habitable-zone planet.
Etude de l’estimateur de la distance minimale pour des modèles de rupture des processus de Poisson : cas avec simulations
DB Ba, AS Dabye, A Diakhaby, GS Lo
Afrika Statistika , 2008,
Abstract: Résumé. Ce travail est consacré aux problèmes d’estimation pour différents modèles de processus de Poisson non homogènes. Nous supposons que la fonction d’intensité du processus de Poisson est discontinue par rapport aux paramètres inconnus. On montre que l’estimateur de la distance minimale est consistant et asymptotiquement normal. Des simulations sont faites pour chaque modèle. Mot-clés : Processus de Poisson, estimation paramétrique, modèle non régulière, estimateur de la distance minimale, propriétés asymptotiques, simulations. Abstract. We consider several problems of parameter estimation by observations of different models of inhomogeneous Poisson processes of discontinuous intensity functions. It is shown that the minimum distance estimators of these parameters are consistent and asymptotically normal. The numerical simulation results are presented as well.
Current and future role of biomarkers in Crohn's disease risk assessment and treatment
Tamboli CP, Doman DB, Patel A
Clinical and Experimental Gastroenterology , 2011, DOI: http://dx.doi.org/10.2147/CEG.S18187
Abstract: rrent and future role of biomarkers in Crohn's disease risk assessment and treatment Review (5453) Total Article Views Authors: Tamboli CP, Doman DB, Patel A Published Date June 2011 Volume 2011:4 Pages 127 - 140 DOI: http://dx.doi.org/10.2147/CEG.S18187 Cyrus P Tamboli1, David B Doman2, Amar Patel3 1Department of Internal Medicine, Division of Gastroenterology, University of Iowa, Iowa City, IA, USA; 2George Washington School of Medicine, Silver Spring, MD, USA; 3Peloton Advantage, LLC, Parsippany, NJ, USA Background: Crohn’s disease (CD), a chronic inflammatory bowel disease (IBD), occurs in genetically susceptible individuals who develop aberrant immune responses to endoluminal bacteria. Recurrent inflammation increases the risk of several complications. Despite use of a traditional “step-up” therapy with corticosteroids and immunomodulators, most CD patients eventually require surgery at some time in their disease course. Newer biologic agents have been remarkably effective in controlling severe disease. Thus, “top-down,” early aggressive therapy has been proposed to yield better outcomes, especially in complicated disease. However, safety and cost issues mandate the need for careful patient selection. Identification of high-risk candidates who may benefit from aggressive therapy is becoming increasingly relevant. Serologic and genetic markers of CD have great potential in this regard. The aim of this review is to highlight the clinical relevance of these markers for diagnostics and prognostication. Methods: A current PubMed literature search identified articles regarding the role of biomarkers in IBD diagnosis, severity prediction, and stratification. Studies were also reviewed on the presence of IBD markers in non-IBD diseases. Results: Several IBD seromarkers and genetic markers appear to be associated with complex CD phenotypes. Qualitative and quantitative serum immune reactivity to microbial antigens may be predictive of disease progression and complications. Conclusion: The cumulative evidence provided by serologic and genetic testing has the potential to enhance clinical decision-making when formulating individualized IBD therapeutic plans.
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