24 research outputs found

    Population genetic structure of Aedes polynesiensis in the Society Islands of French Polynesia: implications for control using a Wolbachia-based autocidal strategy

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    Abstract Background Aedes polynesiensis is the primary vector of Wuchereria bancrofti in the South Pacific and an important vector of dengue virus. An improved understanding of the mosquito population genetics is needed for insight into the population dynamics and dispersal, which can aid in understanding the epidemiology of disease transmission and control of the vector. In light of the potential release of a Wolbachia infected strain for vector control, our objectives were to investigate the microgeographical and temporal population genetic structure of A. polynesiensis within the Society Islands of French Polynesia, and to compare the genetic background of a laboratory strain intended for release into its population of origin. Methods A panel of eight microsatellite loci were used to genotype A. polynesiensis samples collected in French Polynesia from 2005-2008 and introgressed A. polynesiensis and Aedes riversi laboratory strains. Examination of genetic differentiation was performed using F-statistics, STRUCTURE, and an AMOVA. BAYESASS was used to estimate direction and rates of mosquito movement. Results FST values, AMOVA, and STRUCTURE analyses suggest low levels of intra-island differentiation from multiple collection sites on Tahiti, Raiatea, and Maupiti. Significant pair-wise FST values translate to relatively minor levels of inter-island genetic differentiation between more isolated islands and little differentiation between islands with greater commercial traffic (i.e., Tahiti, Raiatea, and Moorea). STRUCTURE analyses also indicate two population groups across the Society Islands, and the genetic makeup of Wolbachia infected strains intended for release is similar to that of wild-type populations from its island of origin, and unlike that of A. riversi. Conclusions The observed panmictic population on Tahiti, Raiatea, and Moorea is consistent with hypothesized gene flow occurring between islands that have relatively high levels of air and maritime traffic, compared to that of the more isolated Maupiti and Tahaa. Gene flow and potential mosquito movement is discussed in relation to trials of applied autocidal strategies.</p

    A randomized clinical trial comparing hydrocolloid, phenytoin and simple dressings for the treatment of pressure ulcers [ISRCTN33429693]

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    BACKGROUND: Pressure sores are important and common complications of spinal cord injury. Many preventive and therapeutic approaches have been tried and new trials are evolving. One relatively recent method is application of a hydrocolloid dressing (HD). In this study we compared the therapeutic effects of HD on pressure ulcer healing with two other topical applications, phenytoin cream (PC) and simple dressing (SD). METHODS: Ninety-one stage I and stage II pressure ulcers of 83 paraplegic male victims of the Iran-Iraq war were randomly allocated to three treatment groups. Mean age and weight of the participants were 36.64 ± 6.04 years and 61.12 ± 5.08 kg, respectively. All the patients were managed in long term care units or in their homes for 8 weeks by a team of general practitioners and nurses, and the ulcer status was recorded as "Complete healing", "Partial healing", "Without improvement" and "Worsening". RESULTS: Complete healing of ulcers, regardless of location and stage, was better in the HD group than the PC [23/31(74.19%) vs 12/30(40%); difference: 34.19%, 95% CI = 10.85–57.52, (P < 0.01)] or the SD [23/31(74.19%) vs 8/30(26.66%); difference: 47.53%, 95% CI = 25.45–69.61, (P < 0.005)] groups. Complete healing of stage I ulcers in the HD group [11/13(85%)] was better than in the SD [5/11(45%); difference: 40%, 95% CI = 4.7–75.22, (P < 0.05)] or PC [2/9 (22%); difference: 63%, 95% CI = 29.69–96.3, (P < 0.005)] groups. Complete healing of stage II ulcer in the HD group [12/18 (67%)] was better than in the SD group [3/19(16%); difference: 51%, 95% CI = 23.73–78.26, (P < 0.005)], but not significantly different from the PC group [10/21 (48%); difference: 19%, 95% CI = -11.47–49.47, (P > 0.05)]. We performed a second analysis considering only one ulcer per patient (i.e. 83 ulcers in 83 patients). This "per patient" analysis showed that complete ulcer healing in the HD group was better than in the PC [20/28(71.4%) vs 11/28 (39.3%); difference: 32.1%, 95% CI = 7.4–56.7, (P < 0.01)] or SD [20/28(71.4%) vs 8/27 (29.6%); difference: 41.8%, 95% CI = 17.7–65.8, (P < 0.005)] groups. CONCLUSION: We deduced that HD is the most effective method investigated for treating stage I and II pressure ulcers in young paraplegic men

    Genetic and ecological outcomes of Inga vera subsp. affinis (leguminosae) tree plantations in a fragmented tropical landscape

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    Planting of native trees for habitat restoration is a widespread practice, but the consequences for the retention and transmission of genetic diversity in planted and natural populations are unclear. Using Inga vera subsp. affinis as a model species, we genotyped five natural and five planted populations in the Atlantic forest of northeastern Brazil at polymorphic microsatellite loci. We studied the breeding system and population structure to test how much genetic diversity is retained in planted relative to natural populations. We then genotyped seedlings from these populations to test whether genetic diversity in planted populations is restored by outcrossing to natural populations of I. vera. The breeding system of natural I. vera populations was confirmed to be highly outcrossing (t = 0.92; FIS = -0.061, P = 0.04), with populations showing weak population substructure (FST = 0.028). Genetic diversity in planted populations was 50% less than that of natural populations (planted: AR = 14.9, HO = 0.865 and natural: AR = 30.8, HO = 0.655). However, seedlings from planted populations showed a 30% higher allelic richness relative to their parents (seedlings AR = 10.5, parents AR = 7.6). Understanding the processes and interactions that shape this system are necessary to provide ecologically sensible goals and successfully restore hyper-fragmented habitats. Future restoration plans for I. vera must consider the genetic diversity of planted populations and the potential for gene flow between natural populations in the landscape, in order to preserve ecological interactions (i.e. pollination), and promote opportunities for outcrossing

    Del./Task Identifier D4.11/T4.5 Work Package WP4: New generation of force feedback devices

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    The purpose of this document is to describe an fMRI (functional Magnetic Resonance Imaging) compatible haptic interface to investigate the mechanisms of tactile perception within an MR environment. This interface allows one translation with force-feedback along a horizontal axis as well as one rotation about a vertical axis linked to the translation. It can be used to move and orient various objects below the finger. The interface and its components MR compatibility properties are analyzed in this report
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