311 research outputs found

    An SDI for the GIS-education at the UGent Geography Department

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    The UGent Geography Department (GD) (ca. 200 students; 10 professors) has been teaching GIS since the mid 90’s. Ever since, GIS has evolved from Geographic Information Systems, to GIScience, to GIServices; implying that a GIS specialist nowadays has to deal with more than just desktop GIS. Knowledge about the interaction between different components of an SDI (spatial data, technologies, laws and policies, people and standards) is crucial for a graduated Master student. For its GIS education, the GD has until recently been using different sources of datasets, which were stored in a non-centralized system. In conformity with the INSPIRE Directive and the Flemish SDI Decree, the GD aims to set-up its own SDI using free and open source software components, to improve the management, user-friendliness, copyright protection and centralization of datasets and the knowledge of state of the art SDI structure and technology. The central part of the system is a PostGIS-database in which both staff and students can create and share information stored in a multitude of tables and schemas. A web-based application facilitates upper-level management of the database for administrators and staff members. Exercises in various courses not only focus on accessing and handling data from the SDI through common GIS-applications as QuantumGIS or GRASS, but also aim at familiarizing students with the set-up of widely used SDI-elements as WMS, WFS and WCS services. The (dis)advantages of the new SDI will be tested in a case study in which the workflow of a typical ‘GIS Applications’ exercise is elaborated. By solving a problem of optimal location, students interact in various ways with geographic data. A comparison is made between the situation before and after the implementation of the SDI

    The battle for chitin recognition in plant-microbe interactions

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    Fungal cell walls play dynamic functions in interaction of fungi with their surroundings. In pathogenic fungi, the cell wall is the first structure to make physical contact with host cells. An important structural component of fungal cell walls is chitin, a well-known elicitor of immune responses in plants. Research into chitin perception has sparked since the chitin receptor from rice was cloned nearly a decade ago. Considering the widespread nature of chitin perception in plants, pathogens evidently evolved strategies to overcome detection, including alterations in the composition of cell walls, modification of their carbohydrate chains and secretion of effectors to provide cell wall protection or target host immune responses. Also non-pathogenic fungi contain chitin in their cell walls and are recipients of immune responses. Intriguingly, various mutualists employ chitin-derived signaling molecules to prepare their hosts for the mutualistic relationship. Research on the various types of interactions has revealed different molecular components that play crucial roles and, moreover, that various chitin-binding proteins contain dissimilar chitin-binding domains across species that differ in affinity and specificity. Considering the various strategies from microbes and hosts focused on chitin recognition, it is evident that this carbohydrate plays a central role in plant-fungus interaction

    Helium balloons for 3D modelling : off to a flying start?

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    Currently, the use of unmanned aerial vehicles (UAV) as a platform for aerial photography is becoming more and more common practice for 3D photo modelling applications. However, the use of these platforms has several drawbacks. Firstly, to recharge the UAV’s batteries a nearby electricity source is needed. This might cause problems when performing research in remote areas. Secondly, a skilled operator is required to control the UAV. Thirdly, there might be legal restrictions to the use of such an aerial platform in several countries. Finally, purchasing a UAV can form a big cost when performing a small project. To address these issues, the use of helium balloons as an alternative and low cost platform for aerial photography is proposed. To assess its efficiency, effectiveness and accuracy, several case studies are elaborated. In the first case study the accuracy of a 3D model created by laser scanning is compared with a 3D model created by helium balloon imagery (Ghent, Belgium). The second case study comprises a test of the performance of the system used at the lake of Vassivière (France). Finally, the helium balloons are deployed on the archaeological site of Edzna (Mexico). Here, a comparison is made between the accuracy of 3D models generated by UAV and helium balloon imagery. In conclusion, the advantages and drawbacks of the use of helium balloons as platform for aerial photography are listed. This allows potential users to make an informed choice between this and other platforms

    Host-dependent type 1 cytokine responses driven by inactivated viruses may fail to default in the absence of IL-12 or IFN-α/β

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    Replicating viruses generally induce type 1 immune responses, with high interferon (IFN)-γ levels and antibodies of the IgG2a isotype. In the present study we demonstrate the intrinsic ability of non-replicating virions to induce comparable immune responses in the notable absence of any adjuvant. Injection of inactivated pseudorabies virus, an alphaherpesvirus, by various routes into mice resulted in the generation of T helper (Th) 1 type immune response. Co-delivery of inactivated pseudorabies herpesvirus (iPRV) with protein redirected IgG1-dominated tetanus toxoid-specific responses towards an IgG1/IgG2a balanced response. Also inactivated preparations of viruses from the paramyxo- (Newcastle disease virus), rhabdo- (rabies virus), corona- (infectious bronchitis virus) and reovirus (avian reovirus) families led to IgG2a antibody responses; however, the genetic background of the host did result in considerable variation. Because disrupted virions also induced type 1 immune responses, we conclude that structural elements of virions inherently contribute to IFN-γ-dependent isotype switching by inactivated viruses. Strikingly, immunizations in gene-disrupted mice showed that a functional IFN-α/β, IFN-γ or interleukin (IL)-12 pathway was not required for the generation of a polarized Th1 type immune response initiated by inactivated virus particles. These findings have a bearing on the understanding of immune responsiveness to virus structures and the design of vaccines containing virus components.</p

    Host-dependent type 1 cytokine responses driven by inactivated viruses may fail to default in the absence of IL-12 or IFN-α/β

    Get PDF
    Replicating viruses generally induce type 1 immune responses, with high interferon (IFN)-γ levels and antibodies of the IgG2a isotype. In the present study we demonstrate the intrinsic ability of non-replicating virions to induce comparable immune responses in the notable absence of any adjuvant. Injection of inactivated pseudorabies virus, an alphaherpesvirus, by various routes into mice resulted in the generation of T helper (Th) 1 type immune response. Co-delivery of inactivated pseudorabies herpesvirus (iPRV) with protein redirected IgG1-dominated tetanus toxoid-specific responses towards an IgG1/IgG2a balanced response. Also inactivated preparations of viruses from the paramyxo- (Newcastle disease virus), rhabdo- (rabies virus), corona- (infectious bronchitis virus) and reovirus (avian reovirus) families led to IgG2a antibody responses; however, the genetic background of the host did result in considerable variation. Because disrupted virions also induced type 1 immune responses, we conclude that structural elements of virions inherently contribute to IFN-γ-dependent isotype switching by inactivated viruses. Strikingly, immunizations in gene-disrupted mice showed that a functional IFN-α/β, IFN-γ or interleukin (IL)-12 pathway was not required for the generation of a polarized Th1 type immune response initiated by inactivated virus particles. These findings have a bearing on the understanding of immune responsiveness to virus structures and the design of vaccines containing virus components.</p

    Design and use of web lectures to enhance GIS teaching and learning strategies : the students' opinions

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    The goal of this research is to design, use and evaluate a set of web lectures, specifically tailored to the needs of students in higher education who follow geographic information system -related courses. Since education in geographic information system includes theoretical concepts and practical experience, both of these teaching strategies will be implemented in the web lectures. The user-centered design approach is used in the design process to increase the acceptance of the web lectures and the motivation to use them: perceived usefulness and ease of use. The results show that the students appreciate the initial set of web lectures, but that they need to be motivated more to use them (especially when theoretical topics are covered). Students still value the "traditional" face-to-face lectures and see the web lectures as an ideal complement

    Acute flaccid myelitis and Guillain-Barre syndrome in children:A comparative study with evaluation of diagnostic criteria

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    BACKGROUND AND PURPOSE: Differentiation between acute flaccid myelitis (AFM) and Guillain–Barré syndrome (GBS) can be difficult, particularly in children. Our objective was to improve the diagnostic accuracy by giving recommendations based on a comparison of clinical features and diagnostic criteria in children with AFM or GBS. METHODS: A cohort of 26 children with AFM associated with enterovirus D68 was compared to a cohort of 156 children with GBS. The specificity of the Brighton criteria, used for GBS diagnosis, was evaluated in the AFM cohort and the specificity of the Centers for Disease Control and Prevention (CDC) AFM diagnostic criteria in the GBS cohort. RESULTS: Children with AFM compared to those with GBS had a shorter interval between onset of weakness and nadir (3 vs. 8 days, p < 0.001), more often had asymmetric limb weakness (58% vs. 0%, p < 0.001), and less frequently had sensory deficits (0% vs. 40%, p < 0.001). In AFM, cerebrospinal fluid leukocyte counts were higher, whereas protein concentrations were lower. Spinal cord lesions on magnetic resonance imaging were only found in AFM patients. No GBS case fulfilled CDC criteria for definite AFM. Of the AFM cases, 8% fulfilled the Brighton criteria for GBS, when omitting the criterion of excluding an alternate diagnosis. CONCLUSIONS: Despite the overlap in clinical presentation, we found distinctive early clinical and diagnostic characteristics for differentiating AFM from GBS in children. Diagnostic criteria for AFM and GBS usually perform well, but some AFM cases may fulfill clinical diagnostic criteria for GBS. This underlines the need to perform diagnostic tests early to exclude AFM in children suspected of atypical GBS
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