46 research outputs found

    Knowledge management and human trafficking: using conceptual knowledge representation, text analytics and open-source data to combat organized crime

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    Globalization, the ubiquity of mobile communications and the rise of the web have all expanded the environment in which organized criminal entities are conducting their illicit activities, and as a result the environment that law enforcement agencies have to police. This paper triangulates the capability of open-source data analytics, ontological knowledge representation and the wider notion of knowledge management (KM) in order to provide an effective, interdisciplinary means to combat such threats, thus providing law enforcement agencies (LEA’s) with a foundation of competitive advantage over human trafficking and other organized crime

    Kondo effect induced by a magnetic field

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    We study peculiarities of transport through a Coulomb blockade system tuned to the vicinity of the spin transition in its ground state. Such transitions can be induced in practice by application of a magnetic field. Tunneling of electrons between the dot and leads mixes the states belonging to the ground state manifold of the dot. Remarkably, both the orbital and spin degrees of freedom of the electrons are engaged in the mixing at the singlet-triplet transition point. We present a model which provides an adequate theoretical description of recent experiments with semiconductor quantum dots and carbon nanotubes

    Kondo effect in coupled quantum dots: a Non-crossing approximation study

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    The out-of-equilibrium transport properties of a double quantum dot system in the Kondo regime are studied theoretically by means of a two-impurity Anderson Hamiltonian with inter-impurity hopping. The Hamiltonian, formulated in slave-boson language, is solved by means of a generalization of the non-crossing approximation (NCA) to the present problem. We provide benchmark calculations of the predictions of the NCA for the linear and nonlinear transport properties of coupled quantum dots in the Kondo regime. We give a series of predictions that can be observed experimentally in linear and nonlinear transport measurements through coupled quantum dots. Importantly, it is demonstrated that measurements of the differential conductance G=dI/dV{\cal G}=dI/dV, for the appropriate values of voltages and inter-dot tunneling couplings, can give a direct observation of the coherent superposition between the many-body Kondo states of each dot. This coherence can be also detected in the linear transport through the system: the curve linear conductance vs temperature is non-monotonic, with a maximum at a temperature TT^* characterizing quantum coherence between both Kondo states.Comment: 20 pages, 17 figure

    Tandem-mirror technology demonstration facility

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    The Earth Law Club was formed by Osgoode Hall Law School students Isabel Dávila Pereira and Jennifer Fischer

    Unusual switchable peroxidase-mimicking nanozyme for the determination of proteolytic biomarker

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    Detection of enzyme biomarkers originating from either bio-fluids or contaminating microorganisms is of utmost importance in clinical diagnostics and food safety. Herein, we present a simple, low-cost and easy-to-use sensing approach based on the switchable peroxidase-mimicking activity of plasmonic gold nanoparticles (AuNPs) that can catalyse for the oxidation of 3,3’,5’5-tetramethylbenzidine (TMB) for the determination of protease enzyme. The AuNP surface is modified with casein, showing dual functionalities. The first function of the coating molecule is to suppress the intrinsic peroxidase-mimicking activity of AuNPs by up to 77.1%, due to surface shielding effects. Secondly, casein also functions as recognition sites for the enzyme biomarker. In the presence of protease, the enzyme binds to and catalyses the degradation of the coating layer on the AuNP surface, resulting in the recovery of peroxidase-mimicking activity. This is shown visually in the development of a blue colored product (oxidised TMB) or spectroscopically as an increase in absorbance at 370 and 650 nm. This mechanism allows for the detection of protease at 44 ng·mL−1 in 90 min. The nanosensor circumvents issues associated with current methods of detection in terms of ease of use, compatibility with point-of-care testing, low-cost production and short analysis time. The sensing approach has also been applied for the detection of protease spiked in ultra-heat treated (UHT) milk and synthetic human urine samples at a limit of detection of 490 and 176 ng·mL−1, respectively, showing great potential in clinical diagnostics, food safety and quality control.[Figure not available: see fulltext.

    Mechanisms of particle transport acceleration in porous media

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    Experimental data show that the groundwater transport of radionuclides in porous media is frequently facilitated when accompanied with colloid particles. This is usually explained by the size exclusion mechanism which implies that the particles move through the largest pores where the flow velocity is higher. We call attention to three other mechanisms which influence the colloid particle motion, while determining both the probable transport facilitation and retardation. First of all, it is shown that the transport facilitation may be significantly reduced and even transformed into a retardation due to the growth of the effective suspension viscosity (a friction-limited facilitation). Secondly, we will show that the transport of particles through the largest pores can be retarded due to a reduced connectivity of the large-pore cluster (a percolation-breakup retardation). Thirdly, we highlight the Fermi mechanism of acceleration known in statistical physics which is based on the elastic collisions between particles. All three effects are analyzed in terms of the velocity enhancement factor, by using statistical models of porous media in the form of a capillary bundle and a 3D capillary network. Optimal and critical regimes of velocity enhancement are quantified. Estimations show that for realistic parameters, the maximal facilitation of colloid transport is close to the experimentally observed data

    Differences in Young Adult Psychopathology Among Drug Abstainers, Experimenters, and Frequent Users

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    Shedler and Block offered the provocative proposal that individuals who experiment with drugs are psychologically healthier than either those who abstain completely or those who are frequent users. Not all studies have come to such conclusions, however. In an effort to specify under what conditions Shedler and Block\u27s conclusions might hold, the present study examined three groups of drug users (abstainers, experimenters, frequent users) classified according to three different criteria: (a) marijuana use at age 20; (b) alcohol use during 10th grade; and (c) alcohol use at age 20. The three groups were compared at age 20 in terms of personality, deviant behavior, and psychopathology. The results revealed that abstainers were never more psychologically impaired, and were occasionally healthier, than experimenters. Frequent users of marijuana were consistently more impaired than both the abstainers and experimenters, in terms of both internalizing and externalizing disorders. Classification according to marijuana use appeared to be more related to psychopathology than did classification according to alcohol use

    Differences in Young Adult Psychopathology Among Drug Abstainers, Experimenters, and Frequent Users

    No full text
    Shedler and Block offered the provocative proposal that individuals who experiment with drugs are psychologically healthier than either those who abstain completely or those who are frequent users. Not all studies have come to such conclusions, however. In an effort to specify under what conditions Shedler and Block\u27s conclusions might hold, the present study examined three groups of drug users (abstainers, experimenters, frequent users) classified according to three different criteria: (a) marijuana use at age 20; (b) alcohol use during 10th grade; and (c) alcohol use at age 20. The three groups were compared at age 20 in terms of personality, deviant behavior, and psychopathology. The results revealed that abstainers were never more psychologically impaired, and were occasionally healthier, than experimenters. Frequent users of marijuana were consistently more impaired than both the abstainers and experimenters, in terms of both internalizing and externalizing disorders. Classification according to marijuana use appeared to be more related to psychopathology than did classification according to alcohol use
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