361 research outputs found
Approximate controllability for some integrodifferential measure driven system with nonlocal conditions
In this work, we focus on a specific category of nonlocal integrodifferential equations. The development of a few new sufficient postulates that guarantee solvability and approxi- mative controllability is described here. We apply the theory of the resolvent operator in the sense of Grimmer, as well as the fixed point strategy and the theory of the Lebesgue-Stieljes integral, in the context of the space of regulated functions. In light of this, the prevalence of our findings is greater than that which is found in the literature. At last, and example is comprised that exhibits the significance of developed theory
Improving the depth sensitivity of time-resolved measurements by extracting the distribution of times-of-flight
Time-resolved (TR) techniques provide a means of discriminating photons based on their time-of-flight. Since early arriving photons have a lower probability of probing deeper tissue than photons with long time-of-flight, time-windowing has been suggested as a method for improving depth sensitivity. However, TR measurements also contain instrument contributions (instrument-response-function, IRF), which cause temporal broadening of the measured temporal point-spread function (TPSF) compared to the true distribution of times-of-flight (DTOF). The purpose of this study was to investigate the influence of the IRF on the depth sensitivity of TR measurements. TPSFs were acquired on homogeneous and two-layer tissue-mimicking phantoms with varying optical properties. The measured IRF and TPSFs were deconvolved using a stable algorithm to recover the DTOFs. The microscopic Beer-Lambert law was applied to the TPSFs and DTOFs to obtain depth-resolved absorption changes. In contrast to the DTOF, the latest part of the TPSF was not the most sensitive to absorption changes in the lower layer, which was confirmed by computer simulations. The improved depth sensitivity of the DTOF was illustrated in a pig model of the adult human head. Specifically, it was shown that dynamic absorption changes obtained from the late part of the DTOFs recovered from TPSFs acquired by probes positioned on the scalp were similar to absorption changes measured directly on the brain. These results collectively demonstrate that this method improves the depth sensitivity of TR measurements by removing the effects of the IRF. © 2013 Optical Society of America
DĂ©veloppement dâun algorithme pour la surveillance de lâincidence du cancer colorectal Ă MontrĂ©al avec les banques donnĂ©es mĂ©dico-administratives de la RAMQ
Contexte : Les meÌthodes actuelles, dâidentification des cas de cancer, utiliseÌes au QueÌbec et ailleurs sont connues pour sous-estimer le fardeau du cancer, en particulier pour certains sous- groupes de population. Les algorithmes utilisant des donneÌes de facturation constituent des options peu couÌteuses pour ameÌliorer la qualiteÌ de la surveillance du cancer, mais nâont pas eÌteÌ mis en place au niveau populationnel.
Objectifs : Nos objectifs eÌtaient de : 1) deÌvelopper un algorithme permettant lâidentification des cas de cancer colorectal (CCR) en utilisant, au niveau populationnel, les donneÌes des hospitalisations et de facturation ; 2) valider lâalgorithme ; et 3) deÌcrire les caracteÌristiques des cas nouvellement captureÌs.
MeÌthodes : Nous avons jumeleÌ les donneÌes de facturation des meÌdecins, des hospitalisations et du fichier des tumeurs (FiTQ) pour 2 013 430 reÌsidents montreÌalais aÌgeÌs de 20 et plus entre le 1er avril 2000 et le 31 mars 2010. Nous avons compareÌ les performances de trois algorithmes baseÌs sur des codes de diagnostics et diffeÌrentes sources de donneÌes. Nous avons valideÌ les cas de CCR identifieÌs en utilisant les codes dâacte de traitement, la reÌpartition par site et les tendances temporelles. Nous avons deÌcrit les cas identifieÌs selon lâaÌge, le sexe, le statut socioeÌconomique et les types de traitement.
ReÌsultats : Notre algorithme baseÌ sur les codes de diagnostics et de traitement identifie 11 476 des 12 933 cas incidents de CCR contenus dans le FiTQ ainsi que 2 317 cas nouvellement captureÌs. Nos cas ont des tendances globales dans le temps et des distributions par site similaires aux donneÌes existantes, ce qui augmente notre confiance en lâalgorithme. Notre algorithme a captureÌ, en termes de pourcentage, plus dâindividus aÌgeÌs de 50 ans et moins chez les cas de CCR nouvellement captureÌs : 8,2 % contre 5,3 %. De plus, les cas nouvellement captureÌs sont plus susceptibles de vivre dans des zones favoriseÌes socioeÌconomiquement.
Conclusions : Notre algorithme fournit un portrait plus complet de lâincidence du CCR aÌ lâeÌchelle de la population que les meÌthodes actuelles dâidentification. Il pourrait eÌtre utiliseÌ pour estimer les tendances de lâincidence aÌ long terme, aider aÌ la surveillance en temps opportun et supporter les interventions, au QueÌbec et dans dâautres provinces ou pays ayant des donneÌes similaires.Background: Cancer case ascertainment methods used in Quebec and elsewhere are known to underestimate the burden of cancer, particularly for certain subgroups. Algorithms using claims data are a low-cost option to improve the quality of cancer surveillance but have not been implemented at the population-level.
Objectives: Our objectives were to 1) develop a colorectal cancer (CRC) case ascertainment algorithm using population-level hospitalization and physician billing data, 2) validate the algorithm, and 3) describe the characteristics of newly-captured cases.
Methods: We linked physician billing, hospitalization, and tumour registry data for 2,013,430 Montreal residents aged 20 + (2000â2010). We compared the performance of three algorithms based on diagnostic codes and different data sources. We validated cases using receipt of treatment, site distribution, and time trends. We described identified cases according to age, sex, socioeconomic status, and treatment patterns.
Results: Our algorithm based on diagnosis and treatment codes identified 11,476 of the 12,933 incident CRC cases contained in the tumour registry as well as 2,317 newly-captured cases. Our cases share similar overall time trends and site distributions to existing data, which increases our confidence in the algorithm. Our algorithm captured, proportionally more individuals aged 50 and younger among newly captured CRC cases: 8.2% vs. 5.3%. Additionally, newly captured cases were more likely to live in socioeconomically advantaged areas.
Conclusions: Our algorithm provides a more complete picture of population-wide CRC incidence than existing case ascertainment methods. It could be used to estimate long-term incidence trends, aid in timely surveillance, and to inform interventions, in both Quebec and other jurisdictions
Neutral stochastic delay partial functional integro-differential equations driven by a fractional Brownian motion
This paper deals with the existence and uniqueness of mild solutions to neutral stochastic delay functional integro-di erential equations perturbed by a fractional Brownian motion BH, with Hurst parameter H 2 ( 1 2; 1). We use the theory of resolvent operators developed in R.Grimmer [5] to show the existence of mild solutions. An example is provided to illustrate the results of this work
Influence de la mutation kdr (L1014F) sur la rĂ©ponse comportementale dâAnopheles gambiae aux insecticides pyrĂ©thrinoĂŻdes.
The blood feeding behaviour is a crucial step in the reproductive cycle of female mosquitoes for egg maturation. However the widespread use of insecticide treated bed nets reduce the ability of mosquitoes to feed on human host. In this context of integrated vector control strategies, mosquitoes have evolve physiological and behavioural adaptations to scope the deleterious effect of insecticides. Despite the progress made on understanding of physiological resistance, few data exist on effects of insecticide treated nets on host seeking behaviour. The aim of my thesis was to determine whether host seeking behaviour of Anopheles gambiae in the presence of insecticide-treated materials is modulated by the presence of the kdr L1014F mutation which confers resistance to pyrethroids used on treated bed nets. Firstly, our results show that the kdr gene modulate the host seeking behaviour in the presence of insecticide treated nettings and the fitness of kdr-resistant mosquitoes. Homozygous resistant mosquitoes for kdr gene have oriented flight to host odours in the presence of permethrin treated net compared to untreated net. The analysis of the performance of the three genotypes to pass through a hole on untreated net in the presence of a vertebrate host showed a cost of kdr mutation on behavioural activity of resistant mosquitoes. In addition, this work highlighted a high performance of heterozygous (overdominance) to pass through a hole treated net to reach a vertebrate host. Finally, our data reveals that a sub-lethal exposure of resistant mosquitoes to two pyrethroid treated nets has a contrasting effect on blood feeding rate. In addition, the pre-exposure of the three genotypes to pyrethroid impact the biting behaviour of susceptible and resistant mosquitoes by reducing the feeding duration, pre-diuresis duration and blood meal size. All of these results are discussed in the context of blood seeking behaviour in natural conditions. Through the study of 3 complementary behavioural sequences, our results brought new insights about the malaria vector behavior in front of pyrethroid-impregnated bed nets and highlighted complex gene-environment interactions.Les parasites du genre Plasmodium responsables du paludisme sont transmis du moustique Ă lâhomme et de lâhomme au moustique pendant la prise du repas de sang. Lâutilisation massive des moustiquaires imprĂ©gnĂ©es dâinsecticides pyrĂ©thrinoĂŻdes vise Ă limiter la prise du repas de sang et Ă rĂ©duire la survie des moustiques. Dans un contexte de lutte antivectorielle gĂ©nĂ©ralisĂ©e, des mĂ©canismes dâadaptations physiologiques et comportementaux ont Ă©tĂ© sĂ©lectionnĂ©s chez les populations dâAnophĂšles vecteurs. Les mĂ©canismes de rĂ©sistances physiologiques font lâobjet dâun large effort de recherche alors que nous ne disposons que de peu de connaissances sur le comportement de recherche et de piqĂ»re dâun homme protĂ©gĂ© par une moustiquaire. Lâobjectif de ce travail de thĂšse Ă©tait de contribuer Ă la comprĂ©hension des interactions entre un mĂ©canisme de rĂ©sistance physiologique aux insecticides, le comportement des moustiques et les outils de lutte antivectorielle. Pour rĂ©aliser cette Ă©tude, nous avons testĂ© lâeffet de la moustiquaire imprĂ©gnĂ©e dâinsecticide sur le comportement de recherche de lâhĂŽte chez Anopheles gambiae en relation avec le gĂ©notype kdr L1014F, qui confĂšre une rĂ©sistance aux pyrĂ©thrinoĂŻdes utilisĂ©s sur les moustiquaires imprĂ©gnĂ©es. Dans la premiĂšre partie, nous avons analysĂ© lâeffet de lâinsecticide pyrĂ©thrinoĂŻde prĂ©sent sur la moustiquaire sur lâattractivitĂ© de lâhĂŽte chez An. gambiae. Nos resultats ont montrĂ© que les moustiques rĂ©sistants Ă©taient plus attirĂ©s par un hĂŽte protĂ©gĂ© par une moustiquaire traitĂ©e de permĂ©thrine comparĂ© une moustiquaire non traitĂ©e. Nous avons ensuite analysĂ© la performance des trois gĂ©notypes kdr Ă atteindre un hĂŽte protĂ©gĂ© par une moustiquaire et leur activitĂ© comportementale au contact de la moustiquaire. Nous avons mis en Ă©vidence dâune part dâun coĂ»t adaptatif du gĂšne kdr sur lâactivitĂ© comportementale des moustiques rĂ©sistants et dâautre part, une meilleure performance des hĂ©tĂ©rozygotes (superdominance) pour localiser une faille sur une moustiquaire traitĂ©e afin dâatteindre un hĂŽte protĂ©gĂ©. Enfin, nos expĂ©riences ont portĂ© sur lâeffet dâune exposition sublĂ©tale des moustiques Ă des insecticides pyrĂ©thrinoĂŻdes sur le comportement de piqĂ»re lors de la recherche dâun hĂŽte protĂ©gĂ©. Cette prĂ©exposition aux pyrĂ©thrinoĂŻdes a eu un effet contrastĂ© sur le taux de gorgement des moustiques rĂ©sistants toutefois elle a rĂ©duit la durĂ©e de gorgement, de prĂ©diurĂšse ainsi que le volume de repas de sang des trois gĂ©notypes. Ă travers lâĂ©tude de 3 sĂ©quences comportementales, nos rĂ©sultats ont permis dâapporter des informations cruciales sur le comportement des anophĂšles vecteurs du paludisme face aux moustiquaires imprĂ©gnĂ©es et ouvre la voie Ă de nombreuses pistes de recherches
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