1,569 research outputs found

    Nonmarket Valuations of Accidental Oil Spills: A Survey of Economic and Legal Principles

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    This paper presents an overview of legal and economic theories used to assess liability and damages for loss of nonmarket goods arising from an accidental oil spill. Several different economic methods used for quantifying values are discussed and critiqued. Also reviewed are the fundamental legal doctrines that permit individuals and public agencies to seek compensation for these damages. To illustrate the applicability of these economic and legal theories, two case studies arc presented and evaluated in terms of the principles presented earlier.Environmental Economics and Policy, International Relations/Trade, Research Methods/ Statistical Methods, Resource /Energy Economics and Policy, Risk and Uncertainty,

    Dirac parameters and topological phase diagram of Pb1-xSnxSe from magneto-spectroscopy

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    Pb1-xSnxSe hosts 3D massive Dirac fermions across the entire composition range for which the crystal structure is cubic. In this work, we present a comprehensive experimental mapping of the 3D band structure parameters of Pb1-xSnxSe as a function of composition and temperature. We cover a parameter space spanning the band inversion that yields its topological crystalline insulator phase. A non-closure of the energy gap is evidenced in the vicinity of this phase transition. Using magnetooptical Landau level spectroscopy, we determine the energy gap, Dirac velocity, anisotropy factor and topological character of Pb1-xSnxSe epilayers grown by molecular beam epitaxy on BaF2 (111). Our results are evidence that Pb1-xSnxSe is a model system to study topological phases and the nature of the phase transition.Comment: Submitte

    Sample clock offset compensation in the fifth-generation new radio downlink

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    In this paper, the authors investigate the issue of sampling clock offset (SCO) in fifth generation new radio systems. Due to the imperfect SCO estimation methods, the correction methods relying on the SCO estimation will not be perfect, so the proposed method directly corrects the effect of SCO without using any kind of estimation methods. Our method can work well in physical downlink shared channel (PDSCH) and use reference signals as recommended by the 3rd generation partnership project (3GPP) standards. Through system-level simulations, the obtained results show that the throughput of the system is improved where the gain difference between the proposed method and the case without SCO compensation arises to reach 25 % over tapped-line (TDL) channel

    Molecular Imaging in Synthetic Biology, and Synthetic Biology in Molecular Imaging

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    Biomedical synthetic biology is an emerging field in which cells are engineered at the genetic level to carry out novel functions with relevance to biomedical and industrial applications. This approach promises new treatments, imaging tools, and diagnostics for diseases ranging from gastrointestinal inflammatory syndromes to cancer, diabetes, and neurodegeneration. As these cellular technologies undergo pre-clinical and clinical development, it is becoming essential to monitor their location and function in vivo, necessitating appropriate molecular imaging strategies, and therefore, we have created an interest group within the World Molecular Imaging Society focusing on synthetic biology and reporter gene technologies. Here, we highlight recent advances in biomedical synthetic biology, including bacterial therapy, immunotherapy, and regenerative medicine. We then discuss emerging molecular imaging approaches to facilitate in vivo applications, focusing on reporter genes for noninvasive modalities such as magnetic resonance, ultrasound, photoacoustic imaging, bioluminescence, and radionuclear imaging. Because reporter genes can be incorporated directly into engineered genetic circuits, they are particularly well suited to imaging synthetic biological constructs, and developing them provides opportunities for creative molecular and genetic engineering

    Quantile stochastic frontier models with endogeneity

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    In this paper, we extend Jradi et al. (2019). First, we use the asymmetric Laplace distribution which is a more reasonable assumption in quantile models. Second, we address the issue of statistical inference for the optimal quantile. Finally, we allow for endogeneity in quantile stochastic frontier models. The new formulation is implemented in a Bayesian framework using Markov Chain Monte Carlo. We employ the celebrated Philippine rice data as in Jradi et al. (2019). Jradi et al. (2019) did not provide efficiency measures which, in our framework, is straightforward to do

    Massive and massless Dirac fermions in Pb1-xSnxTe topological crystalline insulator probed by magneto-optical absorption

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    Dirac fermions in condensed matter physics hold great promise for novel fundamental physics, quantum devices and data storage applications. IV-VI semiconductors, in the inverted regime, have been recently shown to exhibit massless topological surface Dirac fermions protected by crystalline symmetry, as well as massive bulk Dirac fermions. Under a strong magnetic field (B), both surface and bulk states are quantized into Landau levels that disperse as B^1/2, and are thus difficult to distinguish. In this work, magneto-optical absorption is used to probe the Landau levels of high mobility Bi-doped Pb0.54Sn0.46Te topological crystalline insulator (111)-oriented films. The high mobility achieved in these thin film structures allows us to probe and distinguish the Landau levels of both surface and bulk Dirac fermions and extract valuable quantitative information about their physical properties. This work paves the way for future magnetooptical and electronic transport experiments aimed at manipulating the band topology of such materials.Comment: supplementary material included, to appear in Scientific Report

    Antiferromagnetic phase of the gapless semiconductor V3Al

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    Discovering new antiferromagnetic compounds is at the forefront of developing future spintronic devices without fringing magnetic fields. The antiferromagnetic gapless semiconducting D03 phase of V3Al was successfully synthesized via arc-melting and annealing. The antiferromagnetic properties were established through synchrotron measurements of the atom-specific magnetic moments, where the magnetic dichroism reveals large and oppositely-oriented moments on individual V atoms. Density functional theory calculations confirmed the stability of a type G antiferromagnetism involving only two-third of the V atoms, while the remaining V atoms are nonmagnetic. Magnetization, x-ray diffraction and transport measurements also support the antiferromagnetism. This archetypal gapless semiconductor may be considered as a cornerstone for future spintronic devices containing antiferromagnetic elements.Comment: Accepted to Physics Review B on 02/23/1

    A note on Gauge Theories Coupled to Gravity

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    We analyze the bound on gauge couplings em/mpe\geq m/m_p, suggested by Arkani-Hamed et.al. We show this bound can be derived from simple semi-classical considerations and holds in spacetime dimensions greater than or equal to four. Non abelian gauge symmetries seem to satisfy the bound in a trivial manner. We comment on the case of discrete symmetries and close by performing some checks for the bound in higher dimensions in the context of string theory.Comment: 15 pages, 1 figure, Late

    Tactile signatures and hand motion intent recognition for wearable assistive devices

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    Within the field of robotics and autonomous systems where there is a human in the loop, intent recognition plays an important role. This is especially true for wearable assistive devices used for rehabilitation, particularly post-stroke recovery. This paper reports results on the use of tactile patterns to detect weak muscle contractions in the forearm while at the same time associating these patterns with the muscle synergies during different grips. To investigate this concept, a series of experiments with healthy participants were carried out using a tactile arm brace (TAB) on the forearm while performing four different types of grip. The expected force patterns were established by analysing the muscle synergies of the four grip types and the forearm physiology. The results showed that the tactile signatures of the forearm recorded on the TAB align with the anticipated force patterns. Furthermore, a linear separability of the data across all four grip types was identified. Using the TAB data, machine learning algorithms achieved a 99% classification accuracy. The TAB results were highly comparable to a similar commercial intent recognition system based on a surface electromyography (sEMG) sensing
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