1,045 research outputs found

    The role of universities in a network of subsidized R&D collaboration: The case of the biotechnology-industry in Germany

    Get PDF
    This paper contributes to the growing literature on knowledge network evolution. It provides an analysis of the role universities play in a network emerging from the joint participation of organizations in R&D projects subsidized by public authorities. In addition to theorizing universities’ effect on network formation processes, the paper includes an empirical study identifying the main drivers behind the formation of the subsidized network of R&D collaboration in the German biotechnology industry. We find that universities strongly shape the evolution of the network in the period 2007–2010. They are clearly central knowledge sources and dominate the network as partners in many R&D projects. While knowledge links among universities are an essential part of the network, universities are also able to connect local firms to inter-regional knowledge networks. Accordingly, subsidies for joint R&D support universities in acting as regional gatekeepers and thereby facilitate local and inter-regional knowledge diffusion. © 2017 The Author(s

    Daytime lidar measurements of tidal winds in the mesospheric sodium layer at Urbana, Illinois

    Get PDF
    For more than 15 years lidar systems have been used to study the chemistry and dynamics of the mesospheric sodium layer. Because the layer is an excellent tracer of atmospheric wave motions, sodium lidar has proven to be particularly useful for studying the influence of gravity waves and tides on mesospheric dynamics. These waves, which originate in the troposphere and stratosphere, propagate through the mesosphere and dissipate their energy near the mesopause making important contributions to the momentum and turbulence budget in this region of the atmosphere. Recently, the sodium lidar was modified for daytime operation so that wave phenomena and chemical effects could be monitored throughout the complete diurnal cycle. The results of continuous 24 hour lidar observations of the sodium layer structure are presented alond with measurement of the semidiurnal tidal winds

    Ante mortem comparative evaluation of different ELISA systems for diagnosis of porcine Salmonella lnfantis infection

    Get PDF
    Salmonellosis is one of the most important enteric mfections in man and in livestock. Various serotypes of Salmonella entenca can cause a vanety of clinical and subclinical infections, which are mamly self-limiting gastroenteritis or systemic d1seases. Beside Salmonella (S) Typhimurium, S. Derby and S. lnfantis are the most important cause of porcine Salmonella infections. Although pigs usually do not develop clinical salmonellosis, they become carriers and shedders resulting in a substantial disease-causing potential for humans via meat and faeces

    A Machine Learning-Based Raman Spectroscopic Assay for the Identification of Burkholderia mallei and Related Species

    Get PDF
    Burkholderia (B.) mallei, the causative agent of glanders, and B. pseudomallei, the causative agent of melioidosis in humans and animals, are genetically closely related. The high infectious potential of both organisms, their serological cross-reactivity, and similar clinical symptoms in human and animals make the differentiation from each other and other Burkholderia species challenging. The increased resistance against many antibiotics implies the need for fast and robust identification methods. The use of Raman microspectroscopy in microbial diagnostic has the potential for rapid and reliable identification. Single bacterial cells are directly probed and a broad range of phenotypic information is recorded, which is subsequently analyzed by machine learning methods. Burkholderia were handled under biosafety level 1 (BSL 1) conditions after heat inactivation. The clusters of the spectral phenotypes and the diagnostic relevance of the Burkholderia spp. were considered for an advanced hierarchical machine learning approach. The strain panel for training involved 12 B. mallei, 13 B. pseudomallei and 11 other Burkholderia spp. type strains. The combination of top- and sub-level classifier identified the mallei-complex with high sensitivities (>95%). The reliable identification of unknown B. mallei and B. pseudomallei strains highlighted the robustness of the machine learning-based Raman spectroscopic assay

    The derived category of surface algebras: the case of the torus with one boundary component

    Full text link
    In this paper we refine the main result of a previous paper of the author with Grimeland on derived invariants of surface algebras. We restrict to the case where the surface is a torus with one boundary component and give an easily computable derived invariant for such surface algebras. This result permits to give answers to open questions on gentle algebras: it provides examples of gentle algebras with the same AG-invariant (in the sense of Avella-Alaminos and Geiss) that are not derived equivalent and gives a partial positive answer to a conjecture due to Bobi\'nski and Malicki on gentle 22-cycles algebras.Comment: 22 pages, a mistake concerning the computation of the mapping class group has been fixed, version 3: 25 pages, to appear in Algebras and Representation Theor

    Characterisation of ionisation chambers for a mixed radiation field and investigation of their suitability as radiation monitors for the LHC

    Get PDF
    Monitoring of the radiation environment is one of the key tasks in operating a high-energy accelerator such as the Large Hadron Collider (LHC). The radiation fields consist of neutrons, charged hadrons as well as photons and electrons with energy spectra extending from those of thermal neutrons up to several hundreds of GeV. The requirements for measuring the dose equivalent in such a field are different from standard uses and it is thus necessary to investigate the response of monitoring devices thoroughly before the implementation of a monitoring system can be conducted. For the LHC, it is currently foreseen to install argon- and hydrogen-filled high-pressure ionisation chambers as radiation monitors of mixed fields. So far their response to these fields was poorly understood and, therefore, further investigation was necessary to prove that they can serve their function well enough. In this study, ionisation chambers of type IG5 (Centronic Ltd) were characterised by simulating their response functions by means of detailed FLUKA calculations as well as by calibration measurements for photons and neutrons at fixed energies. The latter results were used to obtain a better understanding and validation of the FLUKA simulations. Tests were also conducted at the CERF facility at CERN in order to compare the results with simulations of the response in a mixed radiation field. It is demonstrated that these detectors can be characterised sufficiently enough to serve their function as radiation monitors for the LH

    Detection of Brucella melitensis in bovine milk and milk products from apparently healthy animals in Egypt by real-time PCR

    Get PDF
    Introduction: Brucellosis in Egypt is an endemic disease among animals and humans. In endemic developing countries, dairy products produced from untreated milk are a potential threat to public health. The aim of this study was to detect brucellae in milk and milk products produced from apparently healthy animals to estimate the prevalence of contamination. Methodology: Two hundred and fifteen unpasteurized milk samples were collected from apparently healthy cattle (n = 72) and buffaloes (n = 128) reared on small farms, and from milk shops (n = 15) producing dairy products for human consumption. All milk samples were examined by indirect enzyme-linked immunosorbent assay (iELISA) and real-time PCR (RT-PCR) to detect Brucella antibodies and Brucella-specific DNA, respectively. Results: Using iELISA, anti-Brucella antibodies were detected in 34 samples (16%), while RT-PCR amplified Brucella- specific DNA from 17 milk samples (7.9%). Species-specific IS711 RT-PCR identified 16 of the RT-PCR-positive samples as containing B. melitensis DNA; 1 RT-PCR-positive sample was identified as containing B. abortus DNA. Conclusions: The detection of Brucella DNA in milk or milk products sold for human consumption, especially the highly pathogenic species B. melitensis, is of obvious concern. The shedding of Brucella spp. in milk poses an increasing threat to consumers in Egypt. Consumption of dairy products produced from non- pasteurized milk by individual farmers operating under poor hygienic conditions represents an unacceptable risk to public health

    Adsorption kinetics and equilibria of two methanol samples with different water content on activated carbon

    Get PDF
    To investigate the influence of fluid purity on the adsorption properties, adsorption kinetics and adsorption equilibria of two methanol samples with different water content on an activated carbon were studied. The purity of the methanol samples was 98.5% and 99.9%. Measurements were conducted at 298 K and 318 K using a magnetic suspension balance and cover a wide p/p0 range. To determine effective diffusion time constants and mass transfer coefficients, adsorption kinetics were evaluated using an isothermal and a nonisothermal Fickian diffusion model, and the linear driving force model. The pressure dependence of the kinetic parameters was studied and discussed. A small influence of sample purity on the adsorption equilibria was observed, as the purer methanol sample showed slightly higher equilibrium loadings than the less pure sample. However, significantly faster adsorption kinetics were observed for the purer sample at all temperature and pressure conditions. Compared to the less pure sample, the determined effective diffusion time constants and the mass transfer coefficients were up to 98% and 35% higher, respectively
    • …
    corecore