24,976 research outputs found

    Light Reflectance Characteristics and Remote Sensing of Waterlettuce

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    Waterlettuce ( Pistia stratiotes L.) is a free-floating exotic aquatic weed that often invades and clogs waterways in the southeastern United States. A study was conducted to evaluate the potential of using remote sensing technology to distinguish infestations of waterlettuce in Texas waterways. Field reflectance measurements showed that waterlettuce had higher visible green reflectance than associated plant species. Waterlettuce could be detected in both aerial color- infrared (CIR) photography and videography where it had light pink to pinkish-white image tonal responses. Computer analysis of CIR photographic and videographic images had overall accuracy assessments of 86% and 84%, respectively. (PDF contains 6 pages.

    Coulomb Oscillations of Indium-doped ZnO Nanowire Transistors in a Magnetic Field

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    We report on the observation of Coulomb oscillations from localized quantum dots superimposed on the normal hopping current in ZnO nanowire transistors. The Coulomb oscillations can be resolved up to 20 K. Positive anisotropic magnetoresistance has been observed due to the Lorentz force on the carrier motion. Magnetic field-induced tunneling barrier transparency results in an increase of oscillation amplitude with increasing magnetic field. The energy shift as a function of magnetic field indicates electron wavefunction modification in the quantum dots.Comment: 16 pages, 6 figure

    Effects of neutrino mass hierarchies on dynamical dark energy models

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    We investigate how three different possibilities of neutrino mass hierarchies, namely normal, inverted, and degenerate, can affect the observational constraints on three well known dynamical dark energy models, namely the Chevallier-Polarski-Linder, logarithmic, and the Jassal-Bagla-Padmanabhan parametrizations. In order to impose the observational constraints on the models, we performed a robust analysis using Planck 2015 temperature and polarization data, Supernovae type Ia from Joint Light curve analysis, baryon acoustic oscillations distance measurements, redshift space distortion characterized by f(z)σ8(z)f(z)\sigma_8(z) data, weak gravitational lensing data from Canada-France-Hawaii Telescope Lensing Survey, and cosmic chronometers data plus the local value of the Hubble parameter. We find that different neutrino mass hierarchies return similar fit on almost all model parameters and mildly change the dynamical dark energy properties.Comment: 10 pages, 5 captioned figures, 4 tables; Published version in Phys. Rev.

    Fabrication of transparent conducting amorphous Zn–Sn–In–O thin films by direct current magnetron sputtering

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    Amorphous ZnO–SnO2–In2O3 films were grown by direct current magnetron sputtering from vacuum hot pressed ceramic oxide targets of Zn:In:Sn cation ratios 1:2:1 and 1:2:1.5 onto glass substrates. X-ray diffraction analysis showed that the microstructure remained amorphous during annealing at 200 °C for up to 5 hours. By monitoring the electrical resistivity, oxygen content and substrate temperature were optimized during deposition. The optimal films were characterized by Hall Effect, work function and optical spectroscopy measurements. Films of 1:2:1 composition showed the lowest resistivity (7.6×10−4 Ω-cm), when deposited onto substrates preheated to 300 °C. Transmissivity of all films exceeded 80% in the visible spectral region. The energy gap was 3.52–3.74 eV, and the work function ranged 5.08–5.22 eV, suitable for cathode applications in organic light emitting diodes. Overall, the film characteristics were comparable or superior to those of amorphous tin-doped indium oxide and zinc-doped indium oxide films and may serve as viable, lower-cost alternatives

    Calibrated Fairness in Bandits

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    We study fairness within the stochastic, \emph{multi-armed bandit} (MAB) decision making framework. We adapt the fairness framework of "treating similar individuals similarly" to this setting. Here, an `individual' corresponds to an arm and two arms are `similar' if they have a similar quality distribution. First, we adopt a {\em smoothness constraint} that if two arms have a similar quality distribution then the probability of selecting each arm should be similar. In addition, we define the {\em fairness regret}, which corresponds to the degree to which an algorithm is not calibrated, where perfect calibration requires that the probability of selecting an arm is equal to the probability with which the arm has the best quality realization. We show that a variation on Thompson sampling satisfies smooth fairness for total variation distance, and give an O~((kT)2/3)\tilde{O}((kT)^{2/3}) bound on fairness regret. This complements prior work, which protects an on-average better arm from being less favored. We also explain how to extend our algorithm to the dueling bandit setting.Comment: To be presented at the FAT-ML'17 worksho

    Column froth flotation

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    The froth flotation device includes a flotation column partially filled with a packing which defines a large number of small flow passages extending in a circuitous pattern between the upper and lower portions of the column. A conditioned aqueous pulp of a mineral ore, such as iron ore, is introduced into the midzone of the column. A pressurized inert gas, such as air, is introduced into the bottom of the column and is forced upwardly through the flow passages in the packing. As the air flows upwardly through these flow passages, it is broken into fine bubbles which intimately contact the floatable particles (e.g., iron oxide) in the aqueous pulp and forms a froth concentrate or float fraction which overflows from the top of the column. Wash water is introduced into the top of the column and flows through the flow passages in the packing countercur- rently to the float fraction to scrub entrained non-floata- ble particles (e.g., gangue) from the froth concentrate. A tailing fraction containing the non-floatable particles is withdrawn from the bottom of the column.https://digitalcommons.mtu.edu/patents/1101/thumbnail.jp

    HRTEM study of a new non-stoichiometric BaTiO(3-δ) structure

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    BaTiO3-based multilayer ceramic capacitors (MLCCs) with Ni internal electrodes are co-fired in reducing atmospheres to avoid oxidation of the electrode. Although dielectric materials are doped by acceptor, donor and amphoteric dopants to minimize the oxygen vacancy content, there is still a large concentration of oxygen vacancies that are accommodated in the BaTiO3 active layers. In general, ABO3 perovskites demonstrates a strong ability to accommodate the oxygen vacancies and maintain a regular pseudo-cubic structure. Oxygen deficient barium titanate can be transformed to a hexagonal polymorph (h-BT) at high temperatures1,2. In this paper, we report the new modulated and long range ordered structures of non-stoichiometric BaTiO3-δ that are observed in the electrically degraded Ni-BaTiO3 MLCCs at low temperature

    An MRI-Derived Definition of MCI-to-AD Conversion for Long-Term, Automati c Prognosis of MCI Patients

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    Alzheimer's disease (AD) and mild cognitive impairment (MCI), continue to be widely studied. While there is no consensus on whether MCIs actually "convert" to AD, the more important question is not whether MCIs convert, but what is the best such definition. We focus on automatic prognostication, nominally using only a baseline image brain scan, of whether an MCI individual will convert to AD within a multi-year period following the initial clinical visit. This is in fact not a traditional supervised learning problem since, in ADNI, there are no definitive labeled examples of MCI conversion. Prior works have defined MCI subclasses based on whether or not clinical/cognitive scores such as CDR significantly change from baseline. There are concerns with these definitions, however, since e.g. most MCIs (and ADs) do not change from a baseline CDR=0.5, even while physiological changes may be occurring. These works ignore rich phenotypical information in an MCI patient's brain scan and labeled AD and Control examples, in defining conversion. We propose an innovative conversion definition, wherein an MCI patient is declared to be a converter if any of the patient's brain scans (at follow-up visits) are classified "AD" by an (accurately-designed) Control-AD classifier. This novel definition bootstraps the design of a second classifier, specifically trained to predict whether or not MCIs will convert. This second classifier thus predicts whether an AD-Control classifier will predict that a patient has AD. Our results demonstrate this new definition leads not only to much higher prognostic accuracy than by-CDR conversion, but also to subpopulations much more consistent with known AD brain region biomarkers. We also identify key prognostic region biomarkers, essential for accurately discriminating the converter and nonconverter groups
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