1,120 research outputs found

    Effects of Reflection and Refraction of Ultrasonic Waves on the Angle Beam Inspection of Anisotropic Composite Material

    Get PDF
    Nondestructive testing of composite materials by ultrasonic techniques has several specific features resulting from strong material anisotropy and inhomogeneity. This requires reexamination of old testing methodologies and development of new ones. The latest developments in this direction were recently reviewed by Henneke and Duke [1] and by Bar-Cohen [2]

    The impact of partially missing communities~on the reliability of centrality measures

    Full text link
    Network data is usually not error-free, and the absence of some nodes is a very common type of measurement error. Studies have shown that the reliability of centrality measures is severely affected by missing nodes. This paper investigates the reliability of centrality measures when missing nodes are likely to belong to the same community. We study the behavior of five commonly used centrality measures in uniform and scale-free networks in various error scenarios. We find that centrality measures are generally more reliable when missing nodes are likely to belong to the same community than in cases in which nodes are missing uniformly at random. In scale-free networks, the betweenness centrality becomes, however, less reliable when missing nodes are more likely to belong to the same community. Moreover, centrality measures in scale-free networks are more reliable in networks with stronger community structure. In contrast, we do not observe this effect for uniform networks. Our observations suggest that the impact of missing nodes on the reliability of centrality measures might not be as severe as the literature suggests

    Pediatric Cushing disease: disparities in disease severity and outcomes in the Hispanic and African-American populations.

    Get PDF
    BackgroundLittle is known about the contribution of racial and socioeconomic disparities to severity and outcomes in children with Cushing disease (CD).MethodsA total of 129 children with CD, 45 Hispanic/Latino or African-American (HI/AA) and 84 non-Hispanic White (non-HW), were included in this study. A 10-point index for rating severity (CD severity) incorporated the degree of hypercortisolemia, glucose tolerance, hypertension, anthropomorphic measurements, disease duration, and tumor characteristics. Race, ethnicity, age, gender, local obesity prevalence, estimated median income, and access to care were assessed in regression analyses of CD severity.ResultsThe mean CD severity in the HI/AA group was worse than that in the non-HW group (4.9±2.0 vs. 4.1±1.9, P=0.023); driving factors included higher cortisol levels and larger tumor size. Multiple regression models confirmed that race (P=0.027) and older age (P=0.014) were the most important predictors of worse CD severity. When followed up a median of 2.3 years after surgery, the relative risk for persistent CD combined with recurrence was 2.8 times higher in the HI/AA group compared with that in the non-HW group (95% confidence interval: 1.2-6.5).ConclusionOur data show that the driving forces for the discrepancy in severity of CD are older age and race/ethnicity. Importantly, the risk for persistent and recurrent CD was higher in minority children

    Scintigraphic assessment of bone status at one year following hip resurfacing : comparison of two surgical approaches using SPECT-CT scan

    Get PDF
    Objectives: To study the vascularity and bone metabolism of the femoral head/neck following hip resurfacing arthroplasty, and to use these results to compare the posterior and the trochanteric-flip approaches. Methods: In our previous work, we reported changes to intra-operative blood flow during hip resurfacing arthroplasty comparing two surgical approaches. In this study, we report the vascularity and the metabolic bone function in the proximal femur in these same patients at one year after the surgery. Vascularity and bone function was assessed using scintigraphic techniques. Of the 13 patients who agreed to take part, eight had their arthroplasty through a posterior approach and five through a trochanteric-flip approach. Results: One year after surgery, we found no difference in the vascularity (vascular phase) and metabolic bone function (delayed phase) at the junction of the femoral head/neck between the two groups of patients. Higher radiopharmaceutical uptake was found in the region of the greater trochanter in the trochanteric-flip group, related to the healing osteotomy. Conclusions: Our findings using scintigraphic techniques suggest that the greater intra-operative reduction in blood flow to the junction of the femoral head/neck, which is seen with the posterior approach compared with trochanteric flip, does not result in any difference in vascularity or metabolic bone function one year after surgery

    Tracking mite trophic interactions by multiplex PCR

    Get PDF
    BACKGROUND A thorough knowledge of trophic webs in agroecosystems is essential to achieve successful biological pest control. Phytoseiid mites are the most efficient natural enemies of tetranychid mites, which include several important pests worldwide. Nevertheless, phytoseiids may feed on other food sources including other microarthropods, plants and even other phytoseiids (intraguild predation), which can interfere with biological control services. Molecular gut content analysis is a valuable tool for characterizing trophic interactions, mainly when working on microarthropods such as mites. We have designed new primers for Phytoseiidae, Tetranychidae and Thysanoptera identification and they have been multiplexed in a polymerase chain reaction (PCR) together with universal plant primers. Additionally, we have estimated prey DNA detectability success over time (DS50) considering the most probable events in Spanish citrus orchards: the phytoseiid Euseius stipulatus as a predator, the phytoseiid Phytoseiulus persimilis as intraguild prey, and the thrips Frankliniella occidentalis and Anaphothrips obscurus as alternative prey to Tetranychus urticae. RESULTS The designed multiplex PCR allows the identification of phytoseiids (both predator and intraguild prey) and detects alternative food sources mentioned above in the gut of the phytoseiid predator. DS50 for E. stipulatus as the predator were 1.3, 2.3 and 18.7 h post feeding for F. occidentalis, A. obscurus and P. persimilis as prey, respectively. CONCLUSION Tracking of the trophic relationships within the citrus acarofauna, and the unveiling of the role of alternative food sources will pave the way for enhancing T. urticae biological control. This multiplex PCR approach could be applicable for these purposes in similar agroecosystems

    Comparison of Wolbachia Bacterial Density in Females of Four Thelythokous Strains of Trichogramma cordubensis and T. evanescens (Hymenoptera, Trichogrammatidae)

    Get PDF
    The endosymbionts of the genus Wolbachia infect numerous arthropods and nematods, and often cause different effects on the reproduction of these hosts. The endosymbiotic bacteria Wolbachia induces the thelytokous mode of reproduction in the egg parasitoids of the genus Trichogramma. The Dot-blot technique was performed to compare the symbiont Wolbachia density using the wsp gene of Wolbachia and the 18S gene of Trichogramma. It was established that Wolbachia density is not different in two host species, Trichogramma cordubensis Vargas et Cabello and T. evanescens Haliday.Эндосимбиотические бактерии рода Wolbachia заражают различных артропод и нематод, оказывая различный эффект на их репродуктивные особенности. Бактерии рода Wolbachia вызывают телитокию у яйцеедов рода Trichogramma. Использована техника Dot-blot для сравнения плотности симбионта Wolbachia, с помощью выделения гена wsp у симбионта Wolbachia и гена 18S у Trichogramma. Экспериментально установлено, что плотность Wolbachia у двух видов, Trichogramma cordubensis Vargas et Cabello и T. evanescens Haliday, одинаковая

    Comparative evaluation of Fungitest, Neosensitabs and broth microdilution method for yeasts susceptibility testing

    Full text link
    The need of a simple and reliable method for routine yeasts susceptibility testing led us to evaluate two commercially available methods. We investigated the in vitro susceptibility of 67 clinical isolates (26 C. albicans, 32 C. glabrata, 4 C. krusei, 2 C. tropicalis, 2 C. kefyr and 1 S. cerevisiae) to 6 drugs flucytosine (FC), amphotericin B (A), fluconazole (FZ), itraconazole (IT), kétoconazole (K), miconazole (M), comparing two methods Fungitest (Sanofi Pasteur) and Neosensitabs (Rosco). A broth microdilution adaptation from the NCCLS-M27A procedure was used as reference method. Fungitests consist of individually packed 16 wells microplates containing 6 drugs at two critical concentrations in buffered medium. Reading was performed after 24 and 48h incubation. Neosensitabs is an agar diffusion method on Shadomy agar using antifungals tablets. Reading was performed after 24h. For all strains Neosensitabs was in concordance with NCCLS M27-A for FC (94%), A (98%), FZ (55%) I (53%) with p<0.05. Fungitest correlated with NCCLS method for all antifungals after 24 and 48h incubation time (p<0.05) with respectively 95/95% for FC, 100/100% for A, 80/76% for FZ, 81/55% for I and 93/75% for K, and 88/81 for M. Candida glabrata gave the poorest result with Neosensitabs with 28% concordance for FZand 39% for I; therefore the method can't be recommended for this species. Fungitest concordance observed was 55% for I after 48h. Our results suggest that Fungitest is appropriate for routine yeast susceptibility testing. However itraconazole testing has to be improved with this method
    corecore