66 research outputs found

    Multi-references shape constraint for snakes

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    In this research, we intend to present a new method of snakes with an invariant shape prior. We consider the general case where different templates are available and we have to choose the most suitable ones to define the shape constraint. A new external force is then proposed which is able to take into account several references at the same time with proportional weighting factors. Both a Fourier based shape alignment method and a complete and stable set of shape descriptors are used to ensure invariance and robustness of the prior knowledge to Euclidean transformations. To illustrate the efficiency of our approach, a set of experiments are applied on synthetic and real data. Promising results are obtained and commented

    Perforation Behavior of 304 Stainless Steel Plates at Various Temperatures

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    The effect of temperature on perforation behavior of 304 austenitic stainless steel plates was investigated experimentally. Perforation tests have been conducted at velocities from 80 to 180 m/s and temperatures between − 163 and 200 °C. Low temperatures were obtained using a specific designed cooling device and the temperature distribution on the specimens was verified to be uniform. Based on the experimental results, the failure mode, the initial-residual velocity curves, the ballistic limit velocities and the energy absorption capacity under different temperatures were analyzed. It was found that petalling was the main failure mode during the perforation process. The average number of petals was three at 20 °C or 200 °C and was increasing continuously to five at − 163 °C. The ballistic limit velocity Vbl was also affected by the initial temperature. It increased slightly from 93 m/s at 200 °C to 103 m/s at − 20 °C and then remained constant at lower temperatures. The material showed better energy absorption capacity at low temperatures and this came not only from the temperature sensitivity of the material but also from the strain-induced martensitic transformation effect. According to martensite measurement by X-ray diffraction technique, the martensite fractions along the fracture surface of petals were 87.1%, 66.2%, 52.8% and 32.4% respectively for initial temperatures of − 163 °C, − 60 °C, − 20 °C and 20 °C

    Genetic Diversity Analysis of Onion (Allium cepa L.) from the Arid Region of Tunisia Using Phenotypic Traits and SSR Markers

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    The present study was carried out to evaluate and characterize, for the first time, the genetic potential of a collection of onion (Allium cepa L.) local accessions from the arid region of southern Tunisia. The genetic diversity among 135 onion individuals, belonging to 23 accessions, was evaluated using microsatellite (SSR) markers and phenotypic information. A total of 35 alleles were generated with 11 SSRs. The polymorphic information content (PIC) value ranged from 0.08 to 0.95, with an average PIC of 0.43. The expected heterozygosity averaged 0.37, and the observed heterozygosity averaged 0.42. The analysis of molecular variance (AMOVA) revealed that 79% of genetic variation existed within individuals. Structure and cluster analysis grouped the accessions into two major clusters: landraces and pre-breeding lines. For the phenotypic traits evaluated, field trials were conducted in two different environments. Significant differences among accessions were shown, and for most traits, there was also a significant environmental effect and a significant interaction between environment and accession. Great variability was found for all the traits that could be exploited to create new varieties of onion adapted to local conditions by selecting appropriate parents in hybridization breeding.Esta investigaciĂłn fue financiada en parte por el laboratorio de investigaciĂłn LR21AGR03-ProducciĂłn y ProtecciĂłn para una Horticultura Sostenible, financiado por el Ministerio de EducaciĂłn Superior e InvestigaciĂłn CientĂ­fica de TĂșnez y parcialmente financiado por el proyecto A11-20R financiado por el Gobierno de AragĂłn y por el programa AGROALNEXT apoyado por MCIN con financiaciĂłn de la UniĂłn Europea NextGenerationEU (PRTR-C17.I1).diversitylandracesmicrosatellitesbreedingphenotypicG × E interactionPublishe

    Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

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    Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

    Genetic Structure Analysis of a Collection of Tunisian Durum Wheat Germplasm

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    The Tunisian durum wheat germplasm includes modern cultivars and traditional varieties that are still cultivated in areas where elite cultivars or intensive cultivation systems are not suitable. Within the frame of a collection program of the National Gene Bank of Tunisia (NGBT), durum wheat germplasm was collected from different Tunisian agro-ecological zones. The collected samples were studied using simple sequence repeats (SSRs) markers to explore the genetic diversity and evaluate the genetic structure in Tunisian germplasm. The results demonstrated significant diversity in the Tunisian durum wheat germplasm, with clear differentiation between traditional varieties and modern cultivars. The population structure analysis allowed the identification of five subpopulations, two of which appear to be more strongly represented in germplasm collected in central and southern Tunisia, where environmental conditions at critical development phases of the plant are harsher. Moreover these subpopulations are underrepresented in modern varieties, suggesting that traits of adaptation useful for breeding more resilient varieties might be present in central and southern germplasm. Moreover, our results will support, the activity of in situ on farm conservation of Tunisian durum wheat germplasm started by the National Gene Bank of Tunisia along with the ex situ approach

    Multi-references shape constraint for snakes

    Get PDF
    In this research, we intend to present a new method of snakes with an invariant shape prior. We consider the general case where different templates are available and we have to choose the most suitable ones to define the shape constraint. A new external force is then proposed which is able to take into account several references at the same time with proportional weighting factors. Both a Fourier based shape alignment method and a complete and stable set of shape descriptors are used to ensure invariance and robustness of the prior knowledge to Euclidean transformations. To illustrate the efficiency of our approach, a set of experiments are applied on synthetic and real data. Promising results are obtained and commented

    Raccourcir le temps de déploiement des SFC en interrogeant de maniÚre adaptative les fournisseurs de ressources

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    We consider the SFC embedding (SFCE) problem in the Slice as a Service (SlaaS) model. In this model, a slice provider leases resources from multiple cloud and network providers in order to instantiate the Service Function Chain (SFC) requested by a slice tenant. As the slice provider has no visibility on the infrastructures of the resource providers, in which resources may be purchased and released quite rapidly, it has to query them to determine what are the possible allocations and their costs. We show that when there are many resource providers and many VNFs composing the SFC, the number of queries to be made for discovering a minimum cost SFC embedding grows quickly, leading to excessively long deployment times. In order to reduce the latter quantity, we propose to query resource providers strategically, rather than collecting the information on all possible allocations at once. We provide bounds on the number of queries to be made in this approach, and propose to exploit a Shortest Path Discovery algorithm in order to reduce this number of queries and thus the SFC deployment time. Our numerical results suggest that this algorithm is fairly efficient, in particular when initial estimates of allocation costs can be provided by the slice provider, and that the deployment times can be significantly shortened
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