7,230 research outputs found

    UniquID: A Quest to Reconcile Identity Access Management and the Internet of Things

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    The Internet of Things (IoT) has caused a revolutionary paradigm shift in computer networking. After decades of human-centered routines, where devices were merely tools that enabled human beings to authenticate themselves and perform activities, we are now dealing with a device-centered paradigm: the devices themselves are actors, not just tools for people. Conventional identity access management (IAM) frameworks were not designed to handle the challenges of IoT. Trying to use traditional IAM systems to reconcile heterogeneous devices and complex federations of online services (e.g., IoT sensors and cloud computing solutions) adds a cumbersome architectural layer that can become hard to maintain and act as a single point of failure. In this paper, we propose UniquID, a blockchain-based solution that overcomes the need for centralized IAM architectures while providing scalability and robustness. We also present the experimental results of a proof-of-concept UniquID enrolment network, and we discuss two different use-cases that show the considerable value of a blockchain-based IAM.Comment: 15 pages, 10 figure

    Cumulus cloud venting of mixed layer ozone

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    Observations are presented which substantiate the hypothesis that significant vertical exchange of ozone and aerosols occurs between the mixed layer and the free troposphere during cumulus cloud convective activity. The experiments utilized the airborne Ultra-Violet Differential Absorption Lidar (UV-DIAL) system. This system provides simultaneous range resolved ozone concentration and aerosol backscatter profiles with high spatial resolution. Evening transects were obtained in the downwind area where the air mass had been advected. Space-height analyses for the evening flight show the cloud debris as patterns of ozone typically in excess of the ambient free tropospheric background. This ozone excess was approximately the value of the concentration difference between the mixed layer and free troposphere determined from independent vertical soundings made by another aircraft in the afternoon

    Forms of Limited Practice Under the Medical Practice Act

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    No abstract available. doi:10.2204/iodp.sd.5.07.2007</a

    Potential of hemp (Cannabis sativa L.) for paired phytoremediation and bioenergy production

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    Hemp (Cannabis sativa L.) is a multi-use crop that has been investigated for its potential use in phytoremediation of heavy metals, radionuclides, and organic contaminants, and as a feedstock for bioenergy production. A review of research literature indicates that hemp is a suitable crop for phytoremediation, and a competitive option for bioenergy. Coupling phytoremediation and bioenergy production from a single hemp crop is a potential solution to overcoming the economic constraints of phytoremediation projects. The current challenge is ensuring that the extracted contaminants are not introduced into the consumer marketplace. After several decades of limited research on hemp in the United States, the purpose of this review is to identify the knowledge available for hemp applications in phytoremediation or in production of bioenergy, and if and how those two purposes have been combined. The literature shows that hemp growth has been demonstrated successfully at the field scale for phytoremediation and in several bioenergy conversion technologies. Little is known about the fate of contaminants during hemp growth or during post-harvest processing, especially the relationships between hemp genetics, metabolomics, and contaminant partitioning. Complicating the understanding is the expectation that contaminant fate will be dependent on the contaminant type, the concentration in the material, and the processing methods. Before hemp from phytoremediation applications can be used for bioenergy, the fractionation of heavy metals, radionuclides, and/or organic compounds during transesterification, anaerobic digestion, fermentation, and/or combustion of hemp must be evaluated

    Adverse Effects of Antimicrobials via Predictable or Idiosyncratic Inhibition of Host Mitochondrial Components

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    This minireview explores mitochondria as a site for antibiotic-host interactions that lead to pathophysiologic responses manifested as nonantibacterial side effects. Mitochondrion-based side effects are possibly related to the notion that these organelles are archaic bacterial ancestors or commandeered remnants that have co-evolved in eukaryotic cells; thus, this minireview focuses on mitochondrial damage that may be analogous to the antibacterial effects of the drugs. Special attention is devoted to aminoglycosides, chloramphenicol, and fluoroquinolones and their respective single side effects related to mitochondrial disturbances. Linezolid/oxazolidinone multisystemic toxicity is also discussed. Aminoglycosides and oxazolidinones are inhibitors of bacterial ribosomes, and some of their side effects appear to be based on direct inhibition of mitochondrial ribosomes. Chloramphenicol and fluoroquinolones target bacterial ribosomes and gyrases/topoisomerases, respectively, both of which are present in mitochondria. However, the side effects of chloramphenicol and the fluoroquinolones appear to be based on idiosyncratic damage to host mitochondria. Nonetheless, it appears that mitochondrion-associated side effects are a potential aspect of antibiotics whose targets are shared by prokaryotes and mitochondria—an important consideration for future drug design

    Two dimensionality in quasi one-dimensional cobalt oxides

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    By means of muon spin rotation and relaxation (μ+\mu^+SR) techniques, we have investigated the magnetism of quasi one-dimensional (1D) cobalt oxides AEn+2AE_{n+2}Con+1_{n+1}O3n+3_{3n+3} (AEAE=Ca, Sr and Ba, nn=1, 2, 3, 5 and \infty), in which the 1D CoO3_3 chain is surrounded by six equally spaced chains forming a triangular lattice in the abab-plane, using polycrystalline samples, from room temperature down to 1.8 K. For the compounds with nn=1 - 5, transverse field μ+\mu^+SR experiments showed the existence of a magnetic transition below \sim100 K. The onset temperature of the transition (TconT_{\rm c}^{\rm on}) was found to decrease with nn; from 100 K for nn=1 to 60 K for nn=5. A damped muon spin oscillation was observed only in the sample with nn=1 (Ca3_3Co2_2O6_6), whereas only a fast relaxation obtained even at 1.8 K in the other three samples. In combination with the results of susceptibility measurements, this indicates that a two-dimensional short-range antiferromagnetic (AF) order appears below TconT_{\rm c}^{\rm on} for all compounds with nn=1 - 5; but quasi-static long-range AF order formed only in Ca3_3Co2_2O6_6, below 25 K. For BaCoO3_3 (nn=\infty), as TT decreased from 300 K, 1D ferromagnetic (F) order appeared below 53 K, and a sharp 2D AF transition occurred at 15 K.Comment: 12 pages, 14 figures, and 2 table

    Virtual light-by-light scattering and the g factor of a bound electron

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    The contribution of the light-by-light diagram to the g factor of electron and muon bound in Coulomb field is obtained. For electron in a ground state, our results are in good agreement with the results of other authors obtained numerically for large Z. For relatively small Z our results have essentially higher accuracy as compared to the previous ones. For muonic atoms, the contribution is obtained for the first time with the high accuracy in whole region of Z.Comment: 10 pages, 3 figures, RevTe

    Adolescents’ and adults’ perceptions of ‘natural’, ‘organic’ and ‘additive-free’ cigarettes, and the required disclaimers

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    We sought to investigate adolescents’ and adults’ perceptions of an American Spirit advertisement with “natural,” “organic,” and “additive-free” descriptors and related disclaimers

    Hidden magnetic transitions in thermoelectric layered cobaltite, [Ca2_2CoO3_3]0.62_{0.62}[CoO2_2]

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    A positive muon spin rotation and relaxation (μ+\mu^+SR) experiment on [Ca2_2CoO3_3]0.62_{0.62}[CoO2_2], ({\sl i.e.}, Ca3_3Co4_4O9_9, a layered thermoelectric cobaltite) indicates the existence of two magnetic transitions at \sim 100 K and 400 - 600 K; the former is a transition from a paramagnetic state to an incommensurate ({\sf IC}) spin density wave ({\sf SDW}) state. The anisotropic behavior of zero-field μ+\mu^+SR spectra at 5 K suggests that the {\sf IC-SDW} propagates in the aa-bb plane, with oscillating moments directed along the c-axis; also the {\sf IC-SDW} is found to exist not in the [Ca2_2CoO3_3] subsystem but in the [CoO2_2] subsystem. In addition, it is found that the long-range {\sf IC-SDW} order completes below \sim 30 K, whereas the short-range order appears below 100 K. The latter transition is interpreted as a gradual change in the spin state of Co ions %% at temperatures above 400 K. These two magnetic transitions detected by μ+\mu^+SR are found to correlate closely with the transport properties of [Ca2_2CoO3_3]0.62_{0.62}[CoO2_2].Comment: 7 pages, 8 figures. to be appeared in Phys. Rev.
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