A computerized approach to finding the minimum sample size for single sample attribute sampling plans

Much has been written concerning the determination of a single sampling plan given two points on the operating characteristic (OC) curve. A computer program is presented which will provide minimum sample size for single sample attribute sampling plans. The program provides sampling plans based on the binomial distribution. It incorporates the Fibonacci search technique for discrete valued functions. The search is conducted over an interval, for the variable representing the acceptance number, known to contain the optimal solution. For each point evaluated within this interval, a Fibonacci search is used to determine the least value of the sample size. It is shown how an initial feasible solution could provide the values needed to establish the search intervals. An algorithm already developed to produce integral solutions is used to determine the initial feasible solution. The algorithm developed in this paper is tested to determine its performance. The testing is to illustrate the accuracy of the proposed method. Use of the program also highlights accuracy problems existing with the previous minimum sample size method. Exact solutions are also determined through exhaustive searches for this purpose. A proof of optimality based on the Poisson approximation to the binomial is offered

Feeding behaviour of potential vectors of West Nile virus in Senegal

Background: West Nile virus (WNV) is a widespread pathogen maintained in an enzootic cycle between mosquitoes and birds with occasional spill-over into dead-end hosts such as horses and humans. Migratory birds are believed to play an important role in its dissemination from and to the Palaearctic area, as well as its local dispersion between wintering sites. The Djoudj Park, located in Senegal, is a major wintering site for birds migrating from Europe during the study period (Sept. 2008-Jan. 2009). In this work, we studied the seasonal feeding behaviour dynamics of the potential WNV mosquito vectors at the border of the Djoudj Park, using a reference trapping method (CDC light CO(2)-baited traps) and two host-specific methods (horse- and pigeon-baited traps). Blood meals of engorged females were analysed to determine their origin. Results: Results indicated that Culex tritaeniorhynchus and Cx. neavei may play a key role in the WNV transmission dynamics, the latter being the best candidate bridging-vector species between mammals and birds. Moreover, the attractiveness of pigeon-and horse-baited traps for Cx. neavei and Cx. tritaeniorhynchus varied with time. Finally, Cx. tritaeniorhynchus was only active when the night temperature was above 20 degrees C, whereas Cx. neavei was active throughout the observation period. Conclusions: Cx. neavei and Cx. tritaeniorhynchus are the main candidate vectors for the transmission of WNV in the area. The changes in host attractiveness might be related to variable densities of the migratory birds during the trapping period. We discuss the importance of these results on the risk of WNV transmission in horses and humans

Conveying personality traits trough product design for a symbolic product

Product design, through its sensory attributes, plays a major role in product perceptions and its understanding by consumers. It conveys rich symbolic associations and contributes to shape brand image and its personality traits. A flower is a singular product, expressive and particularly evocative through its design. We postulate that flowers can be considered as brands possessing human-like traits. An experiment being run on two flowers\u27 varieties (tulips and roses) with 509 French participants shows how shape (pointed or rounded petals) and brightness (pink for the light color or purple for the dark color) influence the perceived flower\u27s personality, with gender as a moderating variable. The findings confirm the power of design to shape consumers\u27 perceptions, especially for symbolic products such as flowers

Drivers for Rift Valley fever emergence in Mayotte: A Bayesian modelling approach

Rift Valley fever (RVF) is a major zoonotic and arboviral hemorrhagic fever. The conditions leading to RVF epidemics are still unclear, and the relative role of climatic and anthropogenic factors may vary between ecosystems. Here, we estimate the most likely scenario that led to RVF emergence on the island of Mayotte, following the 2006–2007 African epidemic. We developed the first mathematical model for RVF that accounts for climate, animal imports and livestock susceptibility, which is fitted to a 12-years dataset. RVF emergence was found to be triggered by the import of infectious animals, whilst transmissibility was approximated as a linear or exponential function of vegetation density. Model forecasts indicated a very low probability of virus endemicity in 2017, and therefore of re-emergence in a closed system (i.e. without import of infected animals). However, the very high proportion of naive animals reached in 2016 implies that the island remains vulnerable to the import of infectious animals. We recommend reinforcing surveillance in livestock, should RVF be reported is neighbouring territories. Our model should be tested elsewhere, with ecosystem-specific data

Private patient perceptions about a public programme; what do private Indian tuberculosis patients really feel about directly observed treatment?

<p>Abstract</p> <p>Background</p> <p>India accounts for one-fifth of the global incident cases of tuberculosis(TB). The country presently has the world's largest directly observed treatment, short course (DOTS) programme, that has shown impressive results and covers almost 100% of the billion-plus Indian population. Despite such a successful programme, the majority of Indian patients with tuberculosis prefer private healthcare, although repeated audits of this sector have shown the quality to be poor.</p> <p>We aimed to ascertain the level of awareness and knowledge of private patients with tuberculosis attending our clinic at a tertiary private healthcare institute with regards to the DOTS programme, understanding the reasons behind their preference for private healthcare, and evaluating their perceptions and reasons for accepting or failing to accept directly observed therapy as a treatment option.</p> <p>Methods</p> <p>A structured interview schedule was administered to private patients with tuberculosis at the P.D. Hinduja Hospital and Medical Research Centre, Mumbai, India between January 2006 to November 2007.</p> <p>Results</p> <p>Only 30 of 200 patients (15%) were aware of the DOTS programme. After being explained what directly observed therapy was, 136 patients (68%) found this form of treatment unacceptable.183 patients (91.5%) preferred buying the drugs themselves to visiting a DOTS centre. 90 patients (45%) were not prepared to be observed while swallowing their TB drugs, finding it an intrusion of privacy.</p> <p>Conclusions</p> <p>Our study reveals a poor knowledge and awareness of the DOTS programme among the cohort of TB patients that we interviewed. The control of TB in India will undoubtedly benefit from more patients being attracted to and treated by the existing DOTS programmes. However, directly observed treatment, in its present form, is considered too rigid and intrusive and is unlikely to be accepted by a majority of patients seeking private healthcare. Novel strategies and more flexible options will have to be devised to ensure higher cure rates without compromising patient choice.</p