1,449 research outputs found

    Optimal Collocation Nodes for Fractional Derivative Operators

    Get PDF
    Spectral discretizations of fractional derivative operators are examined, where the approximation basis is related to the set of Jacobi polynomials. The pseudo-spectral method is implemented by assuming that the grid, used to represent the function to be differentiated, may not be coincident with the collocation grid. The new option opens the way to the analysis of alternative techniques and the search of optimal distributions of collocation nodes, based on the operator to be approximated. Once the initial representation grid has been chosen, indications on how to recover the collocation grid are provided, with the aim of enlarging the dimension of the approximation space. As a results of this process, performances are improved. Applications to fractional type advection-diffusion equations, and comparisons in terms of accuracy and efficiency are made. As shown in the analysis, special choices of the nodes can also suggest tricks to speed up computations

    Congenital deformity of the distal extremities in three dogs

    Get PDF
    Congenital limb deformities are very rare conditions and the knowledge about etiology, pathogenesis, clinical presentation and treatment is still poor. Moreover, many defects are still not reported in veterinary literature. This report documents clinical and radiographic findings in three dogs with congenital deformity involving the distal extremities. Case 1 was affected with bilateral aphalangia of the pedes, case 2 presented a combination of brachydactyly and syndactyly, whereas in case 3 a unilateral ectrodactyly was observed. To the authors’ knowledge, brachydactyly, as well as aphalangia, are very uncommon anomalies and have been rarely documented. Moreover, association between syndactyly and brachydactyly has still not been reported

    Implementing and optimizing the operation of membrane bioreactors for petroleum wastewater treatment

    Get PDF
    In the recent Kazakhstan Upstream Oil and Gas Technology and R&D Roadmap, water management has been recognized one of the fifteen main challenges that must be dealt with. This roadmap mentions that chemical processes are increasingly used for wastewater treatment; however it is recognized that "the preferred, longer term solution is likely to be membrane technology, which present a local R&D opportunity since further development is needed. This could lead to local opportunities for design, installation and maintenance of membrane separation equipment"[1]. In line with the above requirements the proposed project develops and optimizes a membrane based treatment scheme for the treating & recycling of the water within the industry. Another objective is to investigate several biological processes within the membrane bioreactor (MBR) including nitrification/denitrification and biological removal of cyanides

    CT findings of thoracolumbar spine lesions in dogs

    Get PDF
    In veterinary medicine, computed tomography (CT) is one of the most commonly used methods for imaging the spine because it provides a detailed examination of the spinal cord and surrounding tissues. The aim of this study was to assess thoracolumbar lesions in a number of dogs studied during the year 2011. There were retrospectively evaluated CT studies from 30 dogs of different breeds (mean age= 6.23 years) presented at the Interdepartmental Center of Radiology in the period January - December 2011, with suspected thoracolumbar vertebral or spinal cord lesions. The CT studies were performed without contrast medium in 27 patients, with contrast medium in subarachnoid space (CT- myelography) in two dogs, and in two patients before and after i.v. administration of contrast medium (Iopamidol 370mgl/ml). In one dog both intravenous and subarachnoid administration of contrast medium were used. There were found 46 disc herniations, 10 degenerative spondylopathies, 5 vertebral malformations, 4 vertebral neoplasia, 4 disc degenerations (mineralization and/or vacuum phenomenon), 4 subdural and epidural hemorrhages, 2 spinal cord degenerations (degenerative myelopathy), 2 radicular neoplasia and 2 discospondylitis. In our sample, there was a prevalence of intervertebral disc herniation and in many cases the same dog showed multiple localizations. Usually, disc herniations were clearly visible without contrast medium, causing different degrees of spinal cord compression. In conclusion, CT demonstrated to be a valuable diagnostic tool for detection and characterization of thoracolumbar spinal lesions in dogs

    Noninvasive Ultrasound Monitoring of Embryonic and Fetal Development in Chinchilla lanigera to Predict Gestational Age: Preliminary Evaluation of This Species as a Novel Animal Model of Human Pregnancy

    Get PDF
    Ultrasound is a noninvasive routine method that allows real-time monitoring of fetal development in utero to determine gestational age and to detect congenital anomalies and multiple pregnancies. To date, the developmental biology of Chinchilla lanigera has not yet been characterized. This species has been found to undergo placentation, long gestation, and fetal dimensions similar to those in humans. The aim of this study was to assess the use of high-frequency ultrasound (HFUS) and clinical ultrasound (US) to predict gestational age in chinchillas and evaluate the possibility of this species as a new animal model for the study of human pregnancy. In this study, 35 pregnant females and a total of 74 embryos and fetuses were monitored. Ultrasound examination was feasible in almost all chinchilla subjects. It was possible to monitor the chinchilla embryo with HFUS from embryonic day (E) 15 to 60 and with US from E15 to E115 due to fetus dimensions. The placenta could be visualized and measured with HFUS from E15, but not with US until E30. From E30, the heartbeat became detectable and it was possible to measure fetal biometrics. In the late stages of pregnancy, stomach, eyes, and lenses became visible. Our study demonstrated the importance of employing both techniques while monitoring embryonic and fetal development to obtain an overall and detailed view of all structures and to recognize any malformation at an early stage. Pregnancy in chinchillas can be confirmed as early as the 15th day postmating, and sonographic changes and gestational age are well correlated. The quantitative measurements of fetal and placental growth performed in this study could be useful in setting up a database for comparison with human fetal ultrasounds. We speculate that, in the future, the chinchilla could be used as an animal model for the study of US in human pregnancy

    Lateral patellar luxation in nine small breed dogs

    Get PDF
    The objective of this paper was to describe the clinical features, the management and the outcome of nine small breed dogs affected with lateral patella luxation referred during the period between January 2010 and December 2014. Patellar luxations were classified according to: breed, age, sex, weight, and grade of patellar luxation, as well as if unilateral or bilateral, and concurrent cranial cruciate ligament lesion. In affected dogs, surgical correction consisted in the combination of tibial tuberosity transposition and soft tissue procedure. Adjunctive condroplasty or trochleoplasty was performed as needing. The outcome was found positive after surgical management with low complication rate and complications have been easily managed with high success rate

    Using geographical information system for spatial evaluation of canine extruded disc herniation

    Get PDF
    Disc herniation is one of the most common pathologies of the vertebral column in dogs. The aim of this study was to develop a geographical information system (GIS)-based vertebral canal (VC) map useful for spatial evaluation of extruded disc herniation (EDH) in dogs. ArcGIS® was used to create two-dimensional and three-dimensional maps, in which the VC surface is divided into polygons by lines representing latitude and longitude. Actual locations and directions of the herniated disc material were assessed by a series of 142 computer tomographies of dogs collected between 2005 and 2013. Most EDHs were located on the cervical and transitional regions (thoraco-lumbar and lumbo-sacral) and shown at the level of the ven- tro-cranial and ventro-central polygons created. Choropleth maps, highlighting the distribution and the location/direction patterns of the EDHs throughout the VC, were produced based on the frequency of the ailment. GIS proved to be a valuable tool in analysing EDH in dogs. Further studies are required for biomechanical analysis of EDH patterns
    corecore