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Search Results: 1 - 8 of 8 matches for " Pyeko Menach "
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Cigarette Smoking and Alcohol Ingestion as Risk Factors for Laryngeal Squamous Cell Carcinoma at Kenyatta National Hospital, Kenya
Pyeko Menach, Herbert O. Oburra and Asmeeta Patel
Clinical Medicine Insights: Ear, Nose and Throat , 2012, DOI: 10.4137/CMENT.S8610
Abstract: Laryngeal squamous cell carcinoma (SCC) is strongly linked to cigarette smoking. It is estimated to account for more than 70% of laryngeal SCCs and up to 89% in combination with alcohol. We wished to determine the prevalence of cigarette smoking and alcohol ingestion among patients with laryngeal squamous cell carcinoma and estimate risk attributed to cigarette smoking and alcohol ingestion. Fifty experimental group patients and fifty controls were recruited of matching age, sex and region of residence. History of smoking and alcohol intake was taken and analyzed to estimate the relative strengths of these exposures. Cessation of smoking was associated with reduced risk of SCC. Smokers had increased risk compared to controls. Those who smoked only had a higher glottic cancer risk. Those who smoked and drank alcohol had a higher supraglottic cancer risk. Being a current smoker and long duration of smoking were independent risk factors of laryngeal SCC.
Cigarette Smoking and Alcohol Ingestion as Risk Factors for Laryngeal Squamous Cell Carcinoma at Kenyatta National Hospital, Kenya
Pyeko Menach,Herbert O. Oburra,Asmeeta Patel
Clinical Medicine Insights: Ear, Nose and Throat , 2012,
Abstract:
Demography and Histologic Pattern of Laryngeal Squamous Cell Carcinoma in Kenya
Owen Pyeko Menach,Asmeeta Patel,Herbert Ouma Oburra
International Journal of Otolaryngology , 2014, DOI: 10.1155/2014/507189
Abstract: Background. Laryngeal squamous cell carcinoma is a common head and neck cancer worldwide. Objective. To determine the demographic characteristics of patients with laryngeal cancer, establish their tumor characteristics and relate it to their smoking and alcohol ingestion habits. Methods. Fifty cases and fifty controls were recruited of matching age, sex, and region of residence. History and pattern of cigarette smoking and alcohol ingestion was taken and analyzed. Results. 33 (66%) of the cases and 3 (6%) among controls were current cigarette smokers. 74% had smoked for more than 30 years, OR 21.3 (95% CI: 2.6–176.1). There was a male predominance (96%) and most cases (62%) were from the ethnic communities in the highland areas of Kenya predominantly in Central and Eastern provinces. Very heavy drinkers had increased risk of OR, 6.0 (95% CI: 1.957–18.398) and those who smoked cigarettes and drank alcohol had poorly differentiated tumors G3, , OR 11.652 (95% CI 2.305–58.895), and G4, OR 7.286 (95% CI 0.726–73.075). They also presented with advanced disease (73.6%). Conclusion. Cigarette smoking and alcohol ingestion are strong risk factors for development of late stage and poorly differentiated laryngeal squamous cell carcinoma in Kenya. 1. Background The commonest causes of death in Kenya are infectious diseases followed closely by cardiovascular illnesses and cancer in that order [1]. Cancer cases in Kenya have however been steadily rising due to the increasing prevalence of cigarette smoking which is a known cause of various neoplasias, more so the upper aerodigestive tract and lung tumors [1, 2]. This rise has been documented and published by the Nairobi Cancer Registry [3], but it is not thought to depict the accurate situation on the ground because cancer diagnosis and notification from health institutions are not as meticulous as desirable. This increase has not been captured in local studies especially with regard to head and neck cancer in general and laryngeal carcinoma in particular. From previous published work, cigarette smoking and alcohol ingestion have been shown to be major risk factors for laryngeal squamous cell carcinoma in this locality as seen in other populations [4]. The incidence of this cancer may increase considering the rising prevalence of smoking in Kenya especially among men in the 45–49 years of age bracket [1, 2]. Moreover, it is also quite worrying that 13% of schooling children smoke cigarettes and, just like in adults, males smoke more than females [5, 6]. If not checked, there is likelihood of increased cancer burden
The unexpected importance of mosquito oviposition behaviour for malaria: non-productive larval habitats can be sources for malaria transmission
Arnaud Menach, F Ellis McKenzie, Antoine Flahault, David L Smith
Malaria Journal , 2005, DOI: 10.1186/1475-2875-4-23
Abstract: Biting and host seeking, not oviposition, have been the focus of most previous studies of mosquitoes and malaria transmission. This study presents a mathematical model that incorporates mosquito oviposition behaviour.The model demonstrates that oviposition is one potential factor explaining heterogeneous biting and vector distribution in a landscape with a heterogeneous distribution of larval habitat. Adult female mosquitoes tend to aggregate around places where they oviposit, thereby increasing the risk of malaria, regardless of the suitability of the habitat for larval development. Thus, a water body may be unsuitable for adult mosquito emergence, but simultaneously, be a source for human malaria.Larval density may be a misleading indicator of a habitat's importance for malaria control. Even if mosquitoes could be lured to oviposit in sprayed larval habitats, this would not necessarily mitigate – and might aggravate – the risk of malaria transmission. Forcing mosquitoes to fly away from humans in search of larval habitat may be a more efficient way to reduce the risk of malaria than killing larvae. Thus, draining, fouling, or filling standing water where mosquitoes oviposit can be more effective than applying larvicide.Malaria is responsible for 700,000 to 2.3 million deaths each year, mainly among children [1]. It is caused by four species of Plasmodium, protozoan parasites that are most common in the tropics, especially Africa, and are transmitted between humans by the bites of female Anopheles mosquitoes. Thus, the distribution of Anopheles mosquitoes is an important factor in determining the prevalence of Plasmodium infections in humans. At large spatial scales (i.e. 100–1,000 kilometers), the distribution of malaria is best described by climate: warm, humid places with standing water support large mosquito populations and high malaria prevalence. At local scales (i.e. 100 metres to one kilometre), the risk of malaria is determined by mosquito behaviour and ec
Heterogeneity, Mixing, and the Spatial Scales of Mosquito-Borne Pathogen Transmission
T. Alex Perkins ,Thomas W. Scott,Arnaud Le Menach,David L. Smith
PLOS Computational Biology , 2013, DOI: 10.1371/journal.pcbi.1003327
Abstract: The Ross-Macdonald model has dominated theory for mosquito-borne pathogen transmission dynamics and control for over a century. The model, like many other basic population models, makes the mathematically convenient assumption that populations are well mixed; i.e., that each mosquito is equally likely to bite any vertebrate host. This assumption raises questions about the validity and utility of current theory because it is in conflict with preponderant empirical evidence that transmission is heterogeneous. Here, we propose a new dynamic framework that is realistic enough to describe biological causes of heterogeneous transmission of mosquito-borne pathogens of humans, yet tractable enough to provide a basis for developing and improving general theory. The framework is based on the ecological context of mosquito blood meals and the fine-scale movements of individual mosquitoes and human hosts that give rise to heterogeneous transmission. Using this framework, we describe pathogen dispersion in terms of individual-level analogues of two classical quantities: vectorial capacity and the basic reproductive number, . Importantly, this framework explicitly accounts for three key components of overall heterogeneity in transmission: heterogeneous exposure, poor mixing, and finite host numbers. Using these tools, we propose two ways of characterizing the spatial scales of transmission—pathogen dispersion kernels and the evenness of mixing across scales of aggregation—and demonstrate the consequences of a model's choice of spatial scale for epidemic dynamics and for estimation of , both by a priori model formulas and by inference of the force of infection from time-series data.
Parallel Sparse Matrix Solver on the GPU Applied to Simulation of Electrical Machines
Antonio Wendell De Oliveira Rodrigues,Frédéric Guyomarch,Yvonnick Le Menach,Jean-Luc Dekeyser
Computer Science , 2010,
Abstract: Nowadays, several industrial applications are being ported to parallel architectures. In fact, these platforms allow acquire more performance for system modelling and simulation. In the electric machines area, there are many problems which need speed-up on their solution. This paper examines the parallelism of sparse matrix solver on the graphics processors. More specifically, we implement the conjugate gradient technique with input matrix stored in CSR, and Symmetric CSR and CSC formats. This method is one of the most efficient iterative methods available for solving the finite-element basis functions of Maxwell's equations. The GPU (Graphics Processing Unit), which is used for its implementation, provides mechanisms to parallel the algorithm. Thus, it increases significantly the computation speed in relation to serial code on CPU based systems.
An elaborated feeding cycle model for reductions in vectorial capacity of night-biting mosquitoes by insecticide-treated nets
Arnaud Le Menach, Shannon Takala, F Ellis McKenzie, Andre Perisse, Anthony Harris, Antoine Flahault, David L Smith
Malaria Journal , 2007, DOI: 10.1186/1475-2875-6-10
Abstract: Using an elaborated description of the classic feeding cycle model, simple formulas have been derived to describe how ITNs change mosquito behaviour and the intensity of malaria transmission, as summarized by vectorial capacity and EIR. The predicted changes are illustrated as a function of the frequency of ITN use for four different vector populations using parameter estimates from the literature.The model demonstrates that ITNs simultaneously reduce mosquitoes' lifespans, lengthen the feeding cycle, and by discouraging human biting divert more bites onto non-human hosts. ITNs can substantially reduce vectorial capacity through small changes to all of these quantities. The total reductions in vectorial capacity differ, moreover, depending on baseline behavior in the absence of ITNs. Reductions in lifespan and vectorial capacity are strongest for vector species with high baseline survival. Anthropophilic and zoophilic species are affected differently by ITNs; the feeding cycle is lengthened more for anthrophilic species, and the proportion of bites that are diverted onto non-human hosts is higher for zoophilic species.This model suggests that the efficacy of ITNs should be measured as a total reduction in transmission intensity, and that the quantitative effects will differ by species and by transmission intensity. At very high rates of ITN use, ITNs can generate large reductions in transmission intensity that could provide very large reductions in transmission intensity, and effective malaria control in some areas, especially when used in combination with other control measures. At high EIR, ITNs will probably not substantially reduce the parasite rate, but when transmission intensity is low, reductions in vectorial capacity combine with reductions in the parasite rate to generate very large reductions in EIR.Insecticide-treated nets (ITNs) are now regarded as standard tools for malaria control [1]. ITNs reduce malaria transmission by vectors that bite during the n
Automatic Multi-GPU Code Generation applied to Simulation of Electrical Machines
Antonio Wendell De Oliveira Rodrigues,Frédéric Guyomarc'H,Jean-Luc Dekeyser,Yvonnick Le Menach
Computer Science , 2011,
Abstract: The electrical and electronic engineering has used parallel programming to solve its large scale complex problems for performance reasons. However, as parallel programming requires a non-trivial distribution of tasks and data, developers find it hard to implement their applications effectively. Thus, in order to reduce design complexity, we propose an approach to generate code for hybrid architectures (e.g. CPU + GPU) using OpenCL, an open standard for parallel programming of heterogeneous systems. This approach is based on Model Driven Engineering (MDE) and the MARTE profile, standard proposed by Object Management Group (OMG). The aim is to provide resources to non-specialists in parallel programming to implement their applications. Moreover, thanks to model reuse capacity, we can add/change functionalities or the target architecture. Consequently, this approach helps industries to achieve their time-to-market constraints and confirms by experimental tests, performance improvements using multi-GPU environments.
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