3,934 research outputs found

    Fate of aflatoxin M1 in cheese whey processing

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    AflatoxinM1 (AFM1) is an important mycotoxin frequently found in milk and in dairy products. It is aminor metabolic product of Aspergillus flavus and A parasiticus. However, it occurs in dairy products as a metabolite formed in cows from aflatoxin B1 contained in animal feeds. In cheese production, AFM1 distributes between curd and whey, being present in products derived from cheese whey processing. In this study, cheese whey from dairy processing was artificially contaminated with the mycotoxin at about 0.1 μg lֿ¹. Ultra-filtration experiments of whey were carried out in order to determinate AFM1 distribution between retentate (protein-rich fraction) and permeate (lactose-rich fraction). Recoveries of AFM1 in retentate were 72.6–86.4% while, in permeate, recoveries were in the range 2.4–14.7%. Partition coefficients of AFM1, lactose and protein were calculated to determine whether there was an interaction between AFM1 and protein. In all experiments, AFM1 partition coefficient was lower than 1, whilst for lactose coefficients close to 1 were determined, showing an affinity of aflatoxin M1 to the protein-rich fraction (retentate)

    Performance Studies of Prototype II for the CASTOR forward Calorimeter at the CMS Experiment

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    We present results of the performance of the second prototype of the CASTOR quartz-tungsten sampling calorimeter, to be installed in the very forward region of the CMS experiment at the LHC. The energy linearity and resolution, as well as the spatial resolution of the prototype to electromagnetic and hadronic showers are studied with E=20-200 GeV electrons, E=20-350 GeV pions, and E=50,150 GeV muons from beam tests carried out at CERN/SPS in 2004. The responses of the calorimeter using two different types of photodetectors (avalanche photodiodes APDs, and photomultiplier tubes PMTs) are compared.Comment: 16 pages, 22 figs., submitted to EPJ-

    Loop mediated isothermal amplification (LAMP) of Theileria annulata DNA

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    In the past three decades, as an alternative to PCR (polymerase chain reaction) new diagnostic techniques like LAMP (loop mediated isothermal amplification) whereby target DNA can be amplified under isothermal conditions without using thermocycler have been developed. The LAMP method allows the synthesis of large amounts of DNA in a short time with high specificity and rapid and easy detection of generated products. In this study, specificity and sensitivity of LAMP method was evaluated for the detection of T. annulata in acute infected and/or carriers cattle using primer pair specifically designed to amplify merozoite surface antigen gene (Mero1), 30 kDa major merozoite surface antigen gene (Tams-1) and cytochrome b gene of T.annulata. Primer pairs with highest sensitivity were used to evaluate the applicability of LAMP to the field samples. Two LAMP primers (CYTOB1 and CYTOB341) targeting cytochrome b gene specifically amplified DNA of different T. annulata isolates successfully while no amplification was seen in other species DNAs and BL20. CYTOB1 primers detected T. annulata Ankara / D7 DNA up to 2 fg, however the detection limit of CYTOB341 was 10 fold lower. The sensitivity of CYTOB1 LAMP assay was same with F3/B3 PCR, however when compared with that of cytob1 PCR a 10 fold lower sensitivity was found. The LAMP product was confirmed by restriction digestion and sequencing. Results obtained from this study indicated that none of the designed primer pairs specific to target genes (Tams-1 and Mero1), except cytochrome b gene was able to specifically and sensitively detect different isolates of T. annulata. Consequently, it was shown that LAMP method using CYTOB1 primers is less effective than the cytob1 PCR in terms of detecting T. annulata in the field sample

    An Audio-Based Vehicle Classifier Using Convolutional Neural Network

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    Audio-based event and scene classification are getting more attention in recent years. Many examples of environmental noise detection, vehicle classification, and soundscape analysis are developed using state of art deep learning techniques. The major noise source in urban and rural areas is road traffic noise. Environmental noise pa-rameters for urban and rural small roads have not been investigated due to some practical reasons. The purpose of this study is to develop an audio-based traffic classifier for rural and urban small roads which have limited or no traffic flow data to supply values for noise mapping and other noise metrics. An audio-based vehicle classifier a convolutional neural network-based algorithm was pro-posed using Mel spectrogram of audio signals as an input feature. Different variations of the network were generated by changing the parameters of the convolu-tional layers and the length of the network. Filter size, number of filters were tested with a dataset prepared with various real-life traffic records and audio extracts from traffic videos. The precision of the networks was evaluated with the common performance metrics. Further assessments were conducted with longer audio files and predictions of the system compared with actual traffic flow. The results showed that convolutional neural networks can be used to classify road traffic noise sources and perform outstandingly for single or double-lane roads

    Is United States’ Economic Power in Decline? Can China Replace the U.S. as the World’s next Economic Superpower?

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    The decline of American economic power has been passionately debated for decades. Starting from the Kennedy administration, there were many cases that declinist scholars interpreted as the beginning of American economic power decline. The financial crisis of 2007-09 is the latest case of the same debate. However, unlike the previous cases, declinist scholars who support the idea of U.S. economic power is in decline after the financial crisis, strongly believe that this time the decline is different. This time the decline is real. In addition, the same scholars also argue that China, as an economic challenger which is different from previous contenders, will replace the U.S. as the world’s next economic superpower. All these concerns made this topic necessary to examine again. In that respect, this paper employs inductive and deductive analysis, scrutinizes qualitative and quantitative data and finds out whether U.S. economic power is in decline and whether China is replacing the U.S. as the world’s next economic superpower. In all, this paper’s results contradict the results of declinist scholars’ studies. For example, contrary to most of declinist scholars’ studies, which state that the financial crisis of 2007-09 created a situation that significantly undermined American economic power, this study finds out that U.S. economic power is not in long-term, fundamental and irreversible decline. It is in a relative decline, a decrease in relative external economic power, like the U.S. experienced several times in the past. From the same perspective, contrary to many declinist scholars who argue that China will displace the U.S. as the world’s next economic superpower, this study reveals that it will be very hard for China to continue its high-paced economic growth in the future. That means rather than displacing the U.S. as the world’s next economic superpower, China’s future will be more about dealing with its own economic problems

    Radiation-Hardness Measurements of High OHOH^{-} Content Quartz Fibres Irradiated with 24 GeV Protons up to 1.25 Grad

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    We investigated the darkening of two high OH- content quartz fibres irradiated with 24 GeV protons at the Cern PS facility IRRAD. The two tested fibres have a 0.6 mm quartz core diameter, one with hard plastic cladding (qp) and the other with quartz cladding (qq). These fibres were exposed at about 1.25 Gigarad in 3 weeks. The fibres became opaque below 380nm, and in the range 580-650 nm. The darkening under irradiation and damage recovery after irradiation as a function of dose and time are similar to what we observed with electrons. The typical attenuation at 455 nm are 1.44 + - 0.22 and 2.20 + - 0.15 dB/m at 100 Mrad for qp and qq fibres, respectively. The maximum damage recovery is also observed near this wavelength

    Ionic Current Rectification Phenomena in Asymmetrical Polymer Nanopores Under Salt Gradients

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    The magnitude of current through a conical nanopore filled with an electrolyte solution depends on the polarity of the applied bias, indicating an asymmetric diode-like current-voltage (I-V) curve. This kind of phenomenon refers to ionic current rectification (ICR), which is of interest because many ion-channel proteins in cellular membranes are rectifying. In addition, ICR in nanopores can be used to control ion concentrations in nano- and microfluidic systems. In this study, the ICR phenomenon through a conical nanopore simultaneously subjected to an electric field and salt concentration gradient is experimentally and numerically investigated. The experiments were conducted in an Izon\u27s SIOS nanopore system, which consisted of a fluid cell with two fluid wells separated by a thermoplastic polyurethane membrane containing a single conical nanopore. The ICR was studied experimentally by imposing a bias voltage ranging from -IV to IV across the two fluid wells filled with potassium chloride (KCI) solutions of two different concentrations. To elucidate the mechanism of ICR, a mathematical model consisting of the Nernst - Planck equations for the ionic mass transport, the Poisson equation for the electrostatics, and the Navier- Stokes equations for the flow field has been developed. The obtained numerical results are in qualitative agreement with the obtained experimental results. In this research, the effect of the imposed electrolyte concentration gradient on the ICR is studied for the first time. Typically, the preferential current direction of a negatively charged nanopore directs from the tip towards the base due to the ion depletion under a negative voltage and ion enrichment under a positive voltage. Furthermore, the preferential current direction of a nanopore highly depends on the externally imposed salt concentration gradient, which makes it possible to tune ICR by altering the salt concentrations in the two fluid reservoirs

    Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

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    A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

    Combined search for the quarks of a sequential fourth generation

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    Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.Comment: Replaced with published version. Added journal reference and DO

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns
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