cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Who's in the Driver's Seat? Mobile Source Policy in the U.S. Federal System
Creators: name: Harrington, Winston
name: McConnell, Virginia D.
name: Walls, Margaret
name: Harrington, Winston
name: McConnell, Virginia D.
name: Walls, Margaret
Publisher: name: Unknown
Year: 1996
Subjects: subject: Public Economics
subject: mobile source
subject: federalism

description: Regulation of mobile source emissions in the US has evolved as a complex combination of central government and decentralized authority. The central government required uniform new car emissions standards in the 1970 Clean Air Act, but gave states the power to meet ambient air quality standards however they saw fit, including various regulations on mobile sources. The 1990 Amendments to the Act strengthened the Federal role in some ways, by requiring tighter new car standards and more specific requirements for fuels and for vehicle emissions inspection and maintenance, but at the same time left states with a great deal of latitude to meet ambient standards and took greater recognition of regional variation in environmental problems. We examine the role of various levels of government in attempts to control vehicle emissions in the U.S., focusing primarily on regulations affecting ambient ozone pollution. Current regulations coming out of the 1990 Amendments are still the subject of much controversy. Several regulations are examined here from the federalist perspective, including the California new car standards and the current debate over "enhanced" inspection and maintenance. We discuss the theoretical basis for national uniform regulations, including production scale economies for new cars, pollution spillovers from one jurisdiction to another, and prevention of state non-compliance with ambient air quality goals. For the analysis of economies of scale in production, we model the trade-offs between gains from scale economies in polluted regions and losses from excess controls in cleaner regions, and illustrate the role of interregional transfers or side-payments. These trade-offs and transfers are particularly important as decisions are being made about whether the "California cars" will be sold only in California or whether they will be sold in the Northeast states and elsewhere. We then look at the debate over enhanced I&M. Finally, we draw some tentative conclusions about the future role of the states versus the central government in US ozone policy.
Sylvia M. Broadbent Papers on the Southern Sierra Miwok Language
Creators: name: Marquez, Freddy
name: Tapia, Mary
name: Aleck, Ned
name: Clifford, George
name: Darrow, Rose
name: Johnson, Castro
name: Lawrence, Johnny
name: Leemee, Chief
name: Lord, Emma
name: Miller, Mrs.  Henry
name: Watt, Rose
name: Broadbent, Sylvia M.
Publisher: name: California Language Archive, University of California, Berkeley
Year: 2015

description: The Papers document Sylvia Broadbent's field research on Miwok languages in 1955-1958 and 1961. The collection includes her original field notebooks and vocabulary file slips, as well as diaries she kept while in the field. Her primary Southern Sierra Miwok linguistic consultants were Chris Brown (a.k.a. Chief Leeme), Castro Johnson, Emma Lord, and Rose Watt. Additional consultants represented in the collection include John Lawrence (Southern Sierra Miwok) and Ned Aleck, George Clifford, Rose Darrow, and Mrs. Henry Miller (Northern Sierra Miwok). The collection also includes an undated set of notes on Ohlone recorded with speaker Maria Tapia.
Casimir Effect for Gauge Scalars: The Kalb-Ramond Case
Creators: name: Barone, F. A.
name: De Moraes, L. M.
name: Helayel-Neto, J. A.
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this work we calculate the functional generator of the Green's functions of the Kalb-Ramond field in 3+1 dimensions. We also calculate the functional generator, and corresponding Casimir energy, of the same field when it is submitted to boundary conditions on two parallel planes. The boundary conditions we consider can be interpreted as a kind of conducting planes for the field in compearing with the Maxwell case. We compare our result with the standard ones for the scalar and Maxwell fields.
description: 10 revtex pages, to be submitted for publication, minor changes
Quantum thermal transistors: Operation characteristics in steady state versus transient regimes
Creators: name: Ghosh, Riddhi
name: Ghoshal, Ahana
name: Sen, Ujjwal
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We show that a quantum thermal transistor can also cause the transistor effect - where one out of three terminals can control the flow of heat current in the other two - with good amplification properties in the transient regime for certain paradigmatic initial states. We find three broad classes of transient quantum thermal transistors - the first having a smaller amplification than the steady state quantum thermal transistor, the second with better amplification but a smaller operating region in terms of temperature, and the third that gives higher amplification with a larger operating region. The last type is of particular interest as it also operates in the region where the steady state thermal transistors lose the transistor effect. We discuss in some detail certain initial states for which the cases of necessarily transient transistors arise. We analyze the time variation of the amplification factor of transient thermal transistors and estimate the preferable time and duration for which they can work efficiently. Cumulative studies of the differences in magnitudes of the amplifications of heat currents at the non-base terminals of the quantum thermal transistor, first with respect to the base-terminal temperature and next with time, are also presented.
description: 14 pages, 13 figures
THE ECONOMICS OF PRIVATE VOLUNTARY ORGANIZATIONS AND COLLECTIVE ACTION IN DEER MANAGEMENT
Creators: name: Steffens, Karin
name: Schmid, A. Allan
name: Steffens, Karin
name: Schmid, A. Allan
Publisher: name: Unknown
Year: 1996
Subjects: Resource /Energy Economics and Policy

description: Game theory and other approaches have been used to characterize problems involving high-exclusion-cost goods which also have the characteristic that marginal cost of an additional user is zero over some range. These analytical tools have made valuable contributions to understanding voluntary organizations and collective action. Resource systems for which composition or scale of the resource is an important factor do not fit neatly into the types of problems which are typically analyzed. The Quality Deer Management Association (QDMA) in Southern Wisconsin is used as an example to illustrate where the existing literature must be modified to take account of particular features of this resource problem. Schelling's multi-person prisoner's dilemma model is modified to incorporate preferences and marginal benefits of deer quality to different types of hunters and to explore issues of resource sustainability. Against the odds, the private QDMA has successfully organized hunters to practice harvesting techniques consistent with improved herd quality.
Victor Golla Papers on the Hupa Language
Creators: name: Jackson, Louisa
name: Jackson, Ned
name: Golla, Victor
Publisher: name: California Language Archive, University of California, Berkeley
Year: 2015

description: The Papers document Golla's work on the Hupa language in preparation for his doctoral dissertation, including field research conducted from 1962-1964. Ned Jackson and Louisa Jackson were his primary Hupa consultants; Golla also worked with Minnie Reeves and Rudolph Socktish. The Papers include digital images of file slips summarizing data from Golla's field notebooks and archival data collected by Edward Sapir.
Exact Results for the Roughness of a Finite Size Random Walk
Creators: name: Alfi, V.
name: Coccetti, F.
name: Marotta, M.
name: Petri, A.
name: Pietronero, L.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We consider the role of finite size effects on the value of the effective Hurst exponent H. This problem is motivated by the properties of the high frequency daily stock-prices. For a finite size random walk we derive some exact results based on Spitzer's identity. The conclusion is that finite size effects strongly enhance the value of H and the convergency to the asymptotic value (H=1/2) is rather slow. This result has a series of conceptual and practical implication which we discuss.
description: 5 pages, 3 figures
title: Experimental Paving Projects Using Curtiss-Wright’s Coal-Modified, Coal-Tar Binder
title: [1960]
titleType: Subtitle
Creators: name: Hardyman, James F.
Publisher: name: Kentucky Transportation Center, University of Kentucky
Year: 1960
Subjects: subject: Transportation Engineering

description: On April 7, 1959, the Curtiss-Wright Corporation announced the development of a new coal-based road paving binder, utilizing bituminous coal. This development was the result of their research program conducted in an effort to find new uses for coal and coal products. The basic principle used in preparing this bituminous binder was the digestion of powdered coal in coal tar and tar oils at temperatures of 500-600°F. By adjusting the proportions of tar, tar oils, and coal, binders could be prepared having penetration ranges comparable to asphalt cements. It was the intent of the developers that the modified binders be used in the same manner as asphalt cements in hot-plant mixtures.
ISSUES AND ALTERNATIVES IN THE 1995 FARM BILL DEBATE: IMPLICATIONS OF THE URUGUAY ROUND OF GATT NEGOTIATIONS
Creators: name: Batie, Sandra S.
name: Schweikhardt, David B.
name: Batie, Sandra S.
name: Schweikhardt, David B.
Publisher: name: Unknown
Year: 1994
Subjects: Agricultural and Food Policy

description: The recently completed round of negotiations under the General Agreement on Tariffs and Trade focused on domestic and international agricultural policies. If this agreement is approved by Congress, U.S. agricultural programs must comply with GATT provisions. The policy choices made during the 1995 farm bill debate about domestic programs, import policies, and export programs could all be affected by the approval of GATT.
Neutrino flavor mixing breaks isotropy in the early universe
Creators: name: Hansen, Rasmus S. L.
name: Shalgar, Shashank
name: Tamborra, Irene
Publisher: name: arXiv
Year: 2020
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The neutrino field is commonly assumed to be isotropic and homogeneous in the early universe. However, due to the large neutrino density, a small perturbation of the isotropy of the neutrino field could potentially be amplified by the non-linear flavor mixing caused by neutrino self-interactions. We carry out the first numerical simulations of the neutrino flavor evolution in a multi-angle anisotropic setting. Due to the computational challenges involved, we adopt a simplified framework consisting of a homogeneous universe with two angle bins -- left and right moving modes -- for neutrinos and antineutrinos, together with an approximate form for the collision term which goes beyond the commonly adopted damping approximation. By assuming a small initial left-right asymmetry of $\mathcal{O}(10^{-15})$, we convincingly demonstrate that flavor evolution can be affected in both mass orderings, with implications on the effective number of thermally excited neutrino species ($N_{\mathrm{eff}}$). Notably, the correction to $N_{\rm eff}$ is comparable to higher order corrections from finite temperature QED effects in normal ordering. In addition, by assuming an initial lepton asymmetry in the neutrino sector of the same order as the baryon one [$\mathcal{O}(10^{-9})$], we find that the neutrino-antineutrino asymmetry grows by several orders of magnitude for isotropic as well as anisotropic initial conditions. This work clearly shows that it is imperative to critically revisit standard assumptions concerning neutrino flavor mixing in the early universe, especially in the light of possible implications on the cosmological observables.
description: 44 pages, 10 figures. Updated with an improved linear stability analysis. Accepted for publication in JCAP
Power dependent switching of nonlinear trapping by local photonic potentials
Creators: name: Shavit, Y.
name: Linzon, Y.
name: Bar-Ad, S.
name: Morandotti, R.
name: Volatier-Ravat, M.
name: Aimez, V.
name: Ares, R.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences

description: We study experimentally and numerically the nonlinear scattering of wave packets by local multi-site guiding centers embedded in a continuous dielectric medium, as a function of the input power and angle of incidence. The extent of trapping into the linear modes of different sites is manipulated as a function of both the input power and incidence angle, demonstrating power-controlled switching of nonlinear trapping by local photonic potentials.
description: Submitted to Optics Letters
Lattice Quantum Electrodynamics in (3+1)-dimensions at finite density with Tensor Networks
Creators: name: Magnifico, Giuseppe
name: Felser, Timo
name: Silvi, Pietro
name: Montangero, Simone
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Gauge theories are of paramount importance in our understanding of fundamental constituents of matter and their interactions. However, the complete characterization of their phase diagrams and the full understanding of non-perturbative effects are still debated, especially at finite charge density, mostly due to the sign-problem affecting Monte Carlo numerical simulations. Here, we report the Tensor Network simulation of a three dimensional lattice gauge theory in the Hamiltonian formulation including dynamical matter: Using this sign-problem-free method, we simulate the ground states of a compact Quantum Electrodynamics at zero and finite charge densities, and address fundamental questions such as the characterization of collective phases of the model, the presence of a confining phase at large gauge coupling, and the study of charge-screening effects.
description: 16 pages, 9 Figures
Practical all-to-all propagators for lattice QCD
Creators: name: Foley, Justin
name: Juge, K. Jimmy
name: O'Cais, Alan
name: Peardon, Mike
name: Ryan, Sinead M.
name: Skullerud, Jon-Ivar
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: A new method for computing all elements of the lattice quark propagator is proposed. The method combines the spectral decomposition of the propagator, computing the lowest eigenmodes exactly, with noisy estimators which are 'diluted', i.e. taken to have support only on a subset of time, space, spin or colour. We find that the errors are dramatically reduced compared to traditional noisy estimator techniques.
description: 24 pages, 18 figures
Large Silicon Abundance in Photodissociation Regions
Creators: name: Okada, Yoko
name: Onaka, Takashi
name: Nakagawa, Takao
name: Shibai, Hiroshi
name: Tomono, Daigo
name: Yui, Yukari Y.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We have made one-dimensional raster-scan observations of the rho Oph and sigma Sco star-forming regions with two spectrometers (SWS and LWS) on board the ISO. In the rho Oph region, [SiII] 35um, [OI] 63um, 146um, [CII] 158um, and the H2 pure rotational transition lines S(0) to S(3) are detected, and the PDR properties are derived as the radiation field scaled by the solar neighborhood value G_0~30-500, the gas density n~250--2500 /cc, and the surface temperature T~100-400 K. The ratio of [SiII] 35um to [OI] 146um indicates that silicon of 10--20% of the solar abundance must be in the gaseous form in the photodissociation region (PDR), suggesting that efficient dust destruction is undergoing even in the PDR and that part of silicon atoms may be contained in volatile forms in dust grains. The [OI] 63um and [CII] 158um emissions are too weak relative to [OI] 146um to be accounted for by standard PDR models. We propose a simple model, in which overlapping PDR clouds along the line of sight absorb the [OI] 63um and [CII] 158um emissions, and show that the proposed model reproduces the observed line intensities fairly well. In the sigma Sco region, we have detected 3 fine-structure lines, [OI] 63um, [NII] 122um, and [CII] 158um, and derived that 30-80% of the [CII] emission comes from the ionized gas. The upper limit of the [SiII] 35um is compatible with the solar abundance relative to nitrogen and no useful constraint on the gaseous Si is obtained for the sigma Sco region.
description: 25 pages with 7 figures, accepted in Astrophysical Journal
ASSESSING THE ECONOMIC IMPACTS OF INTEGRATED PEST MANAGEMENT: LESSONS FROM THE PAST, DIRECTIONS FOR THE FUTURE
Creators: name: Swinton, Scott M.
name: Williams, Mollie B.
name: Swinton, Scott M.
name: Williams, Mollie B.
Publisher: name: Unknown
Year: 1998
Subjects: Crop Production/Industries

description: This paper reviews the literature assessing the economic impacts of integrated pest management (IPM). Definitions of IPM are categorized as input- or outcome-oriented, and an outcome- oriented definition is recommended for public program assessment. The literature on economic impact assessment of IPM is divided according to focus on expected profit, profitability risk, environment, and health. Measuring diverse impacts on the environment and health poses a challenge, as does placing a value on those impacts. Evaluation of environment and health variables has been accomplished either by comparing individual attributes (multiple criteria approach) or else by constructing a weighted index (index approach), which may be measured in monetary or non- monetary terms. While partial budgeting represents an accepted measure of short-term expected profitability effects of IPM practices, the three other focal areas are much more costly and complicated to measure. For routine IPM project assessments, simple indicators of health and environmental impacts are needed that can be used to extrapolate upon valuation measures from prior, published studies.
Boosting Adversarial Attacks on Neural Networks with Better Optimizer
Creators: name: Yin, Heng
name: Zhang, Hengwei
name: Wang, Jindong
name: Dou, Ruiyu
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Convolutional neural networks have outperformed humans in image recognition tasks, but they remain vulnerable to attacks from adversarial examples. Since these data are crafted by adding imperceptible noise to normal images, their existence poses potential security threats to deep learning systems. Sophisticated adversarial examples with strong attack performance can also be used as a tool to evaluate the robustness of a model. However, the success rate of adversarial attacks can be further improved in black-box environments. Therefore, this study combines a modified Adam gradient descent algorithm with the iterative gradient-based attack method. The proposed Adam Iterative Fast Gradient Method is then used to improve the transferability of adversarial examples. Extensive experiments on ImageNet showed that the proposed method offers a higher attack success rate than existing iterative methods. By extending our method, we achieved a state-of-the-art attack success rate of 95.0% on defense models.
The Meta-Variational Quantum Eigensolver (Meta-VQE): Learning energy profiles of parameterized Hamiltonians for quantum simulation
Creators: name: Cervera-Lierta, Alba
name: Kottmann, Jakob S.
name: Aspuru-Guzik, Alán
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We present the meta-VQE, an algorithm capable to learn the ground state energy profile of a parametrized Hamiltonian. By training the meta-VQE with a few data points, it delivers an initial circuit parametrization that can be used to compute the ground state energy of any parametrization of the Hamiltonian within a certain trust region. We test this algorithm with a XXZ spin chain, an electronic H$_{4}$ Hamiltonian and a single-transmon quantum simulation. In all cases, the meta-VQE is able to learn the shape of the energy functional and, in some cases, resulted in improved accuracy in comparison to individual VQE optimization. The meta-VQE algorithm introduces both a gain in efficiency for parametrized Hamiltonians, in terms of the number of optimizations, and a good starting point for the quantum circuit parameters for individual optimizations. The proposed algorithm proposal can be readily mixed with other improvements in the field of variational algorithms to shorten the distance between the current state-of-the-art and applications with quantum advantage.
description: 11 pages, 6 figures, code available
Scalar Dark Matter Candidates -- Revisited
Creators: name: Bœhm, Céline
name: Chu, Xiaoyong
name: Kuo, Jui-Lin
name: Pradler, Josef
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We revisit the possibility of light scalar dark matter, in the MeV to GeV mass bracket and coupled to electrons through fermion or vector mediators, in light of significant experimental and observational advances that probe new physics below the GeV-scale. We establish new limits from electron colliders and fixed-target beams, and derive the strength of loop-induced processes that are probed by precision physics, among other laboratory probes. In addition, we compute the cooling bound from SN1987A, consider self-scattering, structure formation, and cosmological constraints as well as the limits from dark matter-electron scattering in direct detection experiments. We then show that the combination of constraints largely excludes the possibility that the galactic annihilation of these particles may explain the long-standing INTEGRAL excess of 511 keV photons as observed in the galactic bulge. As caveat to these conclusions we identify the resonant annihilation regime where the vector mediator goes nearly on-shell.
description: 22 pages, 9 figures; to match the published version
2003 MICHIGAN TREE FRUIT BUSINESS ANALYSIS SUMMARY
Creators: name: Wittenberg, Eric
name: Harsh, Stephen B.
name: Thornsbury, Suzanne
name: Wittenberg, Eric
name: Harsh, Stephen B.
name: Thornsbury, Suzanne
Publisher: name: Unknown
Year: 2004
Subjects: Crop Production/Industries

description: This report summarizes the financial and production records of 9 Michigan tree fruit farms. To be included, the farms must have produced at least 50 percent of gross cash farm income from one or a combination of sales from cherries, apples, and other fruits. The records came from Michigan State University's TelFarm project. The values were pooled into averages for reporting purposes. Farm records were included if a farm financial summary was completed for 2003 data including beginning and ending balance sheets, plus income and expenses. The data was checked to verify that cash and debt discrepancy were within an acceptable range, cash discrepancy must be less than 10% of gross cash inflow and debt discrepancy must be less than $1,000. While considerable variation in the data exists, average values are reported in the summary tables that follow.
Jacobi Structures in $\mathbb{R}^3$
Creators: name: Haas, F.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Mathematical Physics (math-ph)
subject: Differential Geometry (math.DG)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 53C15; 53D17, 37K05

description: The most general Jacobi brackets in $\mathbb{R}^3$ are constructed after solving the equations imposed by the Jacobi identity. Two classes of Jacobi brackets were identified, according to the rank of the Jacobi structures. The associated Hamiltonian vector fields are also constructed.
Development of graphene-based enzymatic biofuel cells: A minireview
Creators: name: Tang, Jing
name: Yan, Xiaomei
name: Engelbrekt, Christian
name: Ulstrup, Jens
name: Magner, Edmond
name: Xiao, Xinxin
name: Zhang, Jingdong
Publisher: name: University of Limerick
Year: 2024
Subjects: classificationCode: 34
subject: Chemical sciences
subject: FOS: Chemical sciences

description: Enzymatic biofuel cells (EBFCs) have attracted increasing attention due to their potential to harvest energy from a wide range of fuels under mild conditions. Fabrication of effective bioelectrodes is essential for the practical application of EBFCs. Graphene possesses unique physiochemical properties making it an attractive material for the construction of EBFCs. Despite these promising properties, graphene has not been used for EBFCs as frequently as carbon nanotubes, another nanoscale carbon allotrope. This review focuses on current research progress in graphene-based electrodes, including electrodes modified with graphene derivatives and graphene composites, as well as free-standing graphene electrodes. Particular features of graphene-based electrodes such as high conductivity, mechanical flexibility and high porosity for bioelectrochemical applications are highlighted. Reports on graphene-based EBFCs from the last five years are summarized, and perspectives for graphene-based EBFCs are offered.
Sideband transitions in a two-mode Josephson circuit driven beyond the rotating wave approximation
Creators: name: Ann, Byoung-moo
name: Kessels, Wouter
name: Steele, Gary. A.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Driving quantum systems periodically in time plays an essential role in the coherent control of quantum states. The rotating wave approximation (RWA) is a good approximation technique for weak and nearly-resonance driven fields. However, these experiments sometimes require large detuning and strong driving fields, for which the RWA may not hold. In this work, we experimentally, numerically, and analytically explore strongly driven two-mode Josephson circuits in the regime of strong driving and large detuning. Specifically, we investigate beam-splitter and two-mode squeezing interaction between the two modes induced by driving a two-photon sideband transition. Using numerical simulations, we observe that the RWA is unable to correctly capture the amplitude of the sideband transition rates. We verify this finding using an analytical model that is based on perturbative corrections. We find that the breakdown of the RWA in the regime studied does not lead to qualitatively different dynamics, but gives the same results as the RWA theory at higher drive strengths, enhancing the coupling rates compared to what one would predict. This is an interesting consequence compared to the carrier transition case, where the breakdown of the RWA results in qualitatively different time evolution of the quantum state. Our work provides an insight into the behavior of time-periodically driven systems beyond the RWA. We also provide a robust theoretical framework for including these findings in the calculation and calibration of quantum protocols in circuit quantum electrodynamics.
Braking the Gas in the beta Pictoris Disk
Creators: name: Fernández, Rodrigo
name: Brandeker, Alexis
name: Wu, Yanqin
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: (Abridged) The main sequence star beta Pictoris hosts the best studied circumstellar disk to date. Nonetheless, a long-standing puzzle has been around since the detection of metallic gas in the disk: radiation pressure from the star should blow the gas away, yet the observed motion is consistent with Keplerian rotation. In this work we search for braking mechanisms that can resolve this discrepancy. We find that all species affected by radiation force are heavily ionized and dynamically coupled into a single fluid by Coulomb collisions, reducing the radiation force on species feeling the strongest acceleration. For a gas of solar composition, the resulting total radiation force still exceeds gravity, while a gas of enhanced carbon abundance could be self-braking. We also explore two other braking agents: collisions with dust grains and neutral gas. Grains surrounding beta Pic are photoelectrically charged to a positive electrostatic potential. If a significant fraction of the grains are carbonaceous (10% in the midplane and larger at higher altitudes), ions can be slowed down to satisfy the observed velocity constraints. For neutral gas to brake the coupled ion fluid, we find the minimum required mass to be $\approx$ 0.03 $M_\earth$, consistent with observed upper limits of the hydrogen column density, and substantially reduced relative to previous estimates. Our results favor a scenario in which metallic gas is generated by grain evaporation in the disk, perhaps during grain-grain collisions. We exclude a primordial origin for the gas, but cannot rule out the possibility of its production by falling evaporating bodies near the star. We discuss the implications of this work for observations of gas in other debris disks.
description: 19 pages, 12 figures, emulateapj. Accepted for publication in ApJ
RETENTION AND EXPANSION ISSUES AND CONCERNS OF RURAL BUSINESSES: SOME FINDINGS FROM SURVEYS IN THE WESTERN UPPER PENINSULA OF MICHIGAN
Creators: name: Abate-Kassa, Getachew
name: Moser, Colletta H.
name: Abate-Kassa, Getachew
name: Moser, Colletta H.
Publisher: name: Unknown
Year: 2002
Subjects: Community/Rural/Urban Development

description: This paper is part of a series of reports of the activities conducted under a grant from the Fund for Rural America, U.S. Department of Agriculture. Funds for the grant entitled "Enhancing Rural Economies Through Comprehensive Extension, Research & Partnering Approaches Using Multi-County Clusters in Michigan With Application to National Rural Settings" were received by Michigan State University's Department of Agricultural Economics in March, 1998. The major goal of the grant is to increase economic development activity in four clusters of rural counties in Michigan through the utilization of the resources of the Michigan State University Extension Service, Michigan Agricultural Experiment Station, and other resources of Michigan State University. Various local, state, and federal public partners as well as the private sector are co-sponsors of projects in the counties. This paper focuses on Business Retention and Expansion (BR&E) programs that have been conducted in the Western Upper Peninsula (WUP) of Michigan. The paper highlights and assesses major achievements and performances of the programs with respect to identifying issues, problems, and opportunities impacting the local economies. The data include information from BR&E visitation programs supported by the project and two other surveys in the WUP region.
An all-digital associated particle imaging system for the 3D determination of isotopic distributions
Creators: name: Unzueta, Mauricio Ayllon
name: Ludewigt, Bernhard
name: Mak, Brian
name: Tak, Tanay
name: Persaud, Arun
Publisher: name: arXiv
Year: 2020
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: Associated particle imaging (API) is a non-destructive nuclear technique for the 3D determination of isotopic distributions. By detecting the alpha particle associated with the emitted neutron in the deuterium-tritium fusion reaction with a position- and time-resolving detector, the direction of the 14.1 MeV neutron and its time of emission can be determined. Employing this method, isotope characteristic gamma rays emitted in inelastic neutron scattering events can be correlated with the neutron interaction location. An API system consisting of a sealed-type neutron generator, gamma detectors, and a position-sensitive alpha detector was designed, constructed, and characterized. The system was tested with common soil elements and shown to be sensitive to 12C, 16O, 28Si, 27Al, and 56Fe. New aspects of our approach are the use of a yttrium-aluminum-perovskite (YAP) scintillator, using a sapphire window instead of a fiber-optic faceplate for light transport to the photomultiplier, and the all-digital data acquisition system. We present a description of the system with simulations and experimental results that show a position resolution on the alpha detector of 1 mm, a depth resolution using a LaBr3 detector of 6.2 cm, and an angular resolution of 4.5 degrees. Additionally, we present single-element gamma response measurements for the elements mentioned above together with a comparison to Monte Carlo simulations (MCNP6).
Fabrication and superconductivity of NaxTaS2 crystals
Creators: name: Fang, L.
name: Wang, Y.
name: Zou, P. Y.
name: Tang, L.
name: Xu, Z.
name: Chen, H.
name: Dong, C.
name: Shan, L.
name: Wen, H. H.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: In this paper we report the growth and superconductivity of $Na_xTaS_2$ crystals. The structural data deduced from X-ray diffraction pattern shows that the sample has the same structure as $2H-TaS_2$. A series of crystals with different superconducting transition temperatures ($T_c$) ranging from 2.5 K to 4.4 K were obtained. It is found that the $T_c$ rises with the increase of $Na$ content determined by Energy-Dispersive x-ray microanalysis(EDX) of Scanning Electron Microscope (SEM) on these crystals. Compared with the resistivity curve of un-intercalated sample $2H-TaS_2$ ($T_c$ = 0.8 K, $T_{CDW} \approx$ 70 K), no signal of charge density wave (CDW) was observed in samples $Na_{0.1}TaS_2$ and $Na_{0.05}TaS_2$. However, in some samples with lower $T_c$, the CDW appears again at about 65 K. Comparison between the anisotropic resistivity indicates that the anisotropy becomes smaller in samples with more $Na$ intercalation (albeit a weak semiconducting behavior along c-axis) and thus higher $T_c$. It is thus concluded that there is a competition between the superconductivity and the CDW. With the increase of sodium content, the rise of $T_c$ in $Na_xTaS_2$ is caused mainly by the suppression to the CDW in $2H-TaS_2$, and the conventional rigid band model for layered dichalcogenide may be inadequate to explain the changes induced by the slight intercalation of sodium in $2H-TaS_2$.
description: 8 pages, 13 figures, To appear in Physical Review B
Causal Discovery using Compression-Complexity Measures
Creators: name: SY, Pranay
name: Nagaraj, Nithin
Publisher: name: arXiv
Year: 2020
Subjects: subject: Machine Learning (cs.LG)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences
subject: 62D20 (Primary) 68P30, 68Q30, 94A17 (Secondary)

description: Causal inference is one of the most fundamental problems across all domains of science. We address the problem of inferring a causal direction from two observed discrete symbolic sequences $X$ and $Y$. We present a framework which relies on lossless compressors for inferring context-free grammars (CFGs) from sequence pairs and quantifies the extent to which the grammar inferred from one sequence compresses the other sequence. We infer $X$ causes $Y$ if the grammar inferred from $X$ better compresses $Y$ than in the other direction. To put this notion to practice, we propose three models that use the Compression-Complexity Measures (CCMs) - Lempel-Ziv (LZ) complexity and Effort-To-Compress (ETC) to infer CFGs and discover causal directions without demanding temporal structures. We evaluate these models on synthetic and real-world benchmarks and empirically observe performances competitive with current state-of-the-art methods. Lastly, we present two unique applications of the proposed models for causal inference directly from pairs of genome sequences belonging to the SARS-CoV-2 virus. Using a large number of sequences, we show that our models capture directed causal information exchange between sequence pairs, presenting novel opportunities for addressing key issues such as contact-tracing, motif discovery, evolution of virulence and pathogenicity in future applications.
description: Accepted version with major revisions to results and discussion. 17 pages, 9 figures
Quantum simulation of three-body interactions in weakly driven quantum systems
Creators: name: Petiziol, Francesco
name: Sameti, Mahdi
name: Carretta, Stefano
name: Wimberger, Sandro
name: Mintert, Florian
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: The realization of effective Hamiltonians featuring many-body interactions beyond pairwise coupling would enable the quantum simulation of central models underpinning topological physics and quantum computation. We overcome crucial limitations of perturbative Floquet engineering and discuss the highly accurate realization of a purely three-body Hamiltonian in superconducting circuits and molecular nanomagnets.
description: 6+8 pages, 3+4 figures
2001 ANNUAL AGRICULTURAL OUTLOOK
Creators: name: Hilker, James H.
name: Alderman, Nicole
name: Hilker, James H.
name: Alderman, Nicole
Publisher: name: Unknown
Year: 2001
Subjects: Farm Management

description: One word summarizes the current outlook for the U.S. economy. That word is confusion. First, we review the recent behavior of the U.S. economy. Ten years of economic expansion without a recession had led some to believe that we could have continual expansion without a recession. The year 2000 was the fourth year in a row with growth exceeding 4 percent and this was accomplished with relatively stable prices. unemployment was about 4 percent or below what many perceived as a sustainable rate of unemployment without rapid inflation. Stock market prices had increased and some consumers were spending their "new wealth." However, the stock market showed signs of weakness beginning in 1999. That weakness grew, especially for technology stocks and price volatility became much larger. Energy prices also increased in volatility with gasoline, natural gas and electric rates changing frequently except where highly regulated. The economy continued to show strength through much of the year in spite of these problems. Then a series of events led to a major shift in consumer attitudes which began in the final quarter of the year.
Modern meson spectroscopy: the fundamental role of unitarity
Creators: name: van Beveren, Eef
name: Rupp, George
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: The importance of $S$-matrix unitarity in realistic meson spectroscopy is reviewed, both its historical development and more recent applications. First the effects of imposing $S$-matrix unitarity on meson resonances is demonstrated in both the elastic and the inelastic case. Then, the static quark model is revisited and its theoretical as well as phenomenological shortcomings are highlighted. A detailed account is presented of the mesons in the tables of the Particle Data Group that cannot be explained at all or only poorly in models describing mesons as pure quark-antiquark bound states. Next the earliest unitarised and coupled-channel models are revisited, followed by several examples of puzzling meson resonances and their understanding in a modern unitarised framework. Also, recent and fully unquenched lattice descriptions of such mesons are summarised. Finally, attention is paid to production processes, which require an unconventional yet related unitary approach. Proposals for further improvement are discussed.
description: Invited review paper, 51 pages, 16 figures, 4 tables; to be published in "Progress in Particle and Nuclear Physics" 2021. v2: several typos corrected, in particular in Eqs. (15), (17), (36), and (37) in Section 2; some accompanying remarks rephrased for clarity; Eq. (41) improved. NOTE: v3 is identical to v2; published version (in print and online) largely corresponds to v1; v3 (=v2) is correct
PRIVATIZING MARKETS FOR HETEROGENEOUS, EXPERIENCE GOODS: COFFEE IN NORTHWEST CAMEROON
Creators: name: Wessen, Paul D.
name: Oehmke, James F.
name: Wessen, Paul D.
name: Oehmke, James F.
Publisher: name: Unknown
Year: 2001
Subjects: subject: Marketing
subject: FOS: Economics and business

description: Reform and privatization of administratively controlled marketing parastatals is always a thorny issue. Reform of public coffee parastatals is one of the most fascinating-and trickiest-exercises in free-market development. Coffee, a heterogenous, experience good, undergoes several processing stages with imperfect quality control, leading to agency problems. Successful privatization must address these problems. This paper analyzes the reform and partial privatization of the North West Cooperative Association (NWCA) parastatal in Cameroon. A conceptual, principal-agent framework informs the analysis. In an interesting twist, the reforms structured the marketing chain so that farmers are the residual claimants to profits from international sales, in effect making them the principals. As is suggested by the conceptual framework, empirical work confirms that farmers as principals have reinvested in coffee quality. However, the evidence also shows that agency problems still exist at later stages of the marketing chain. This is consistent with the principal-agent framework, since incentive-compatible contracts are not used in this marketing chain. The paper concludes by drawing more general lessons about how incomplete information and incentive structure issues arising from imperfect markets might be handled within the context of market liberalization.
Astrophysical Production of Microscopic Black Holes in a Low Planck-scale World
Creators: name: Barrau, A.
name: Feron, C.
name: Grain, J.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In the framework of brane-world models lowering the Planck scale to the TeV range, it has recently been pointed out that small black holes could be formed at particle colliders or by neutrinos interactions in the atmosphere. This article aims at reviewing other places and epochs where microscopic black holes could be formed : the interstellar medium and the early Universe. The related decay channels and the propagation of the emitted particles are studied to conclude that, in spite of the large creation rate for such black holes, the amount of produced particles do not conflict with experimental data. This shows, from the astronomical viewpoint, that models with large extra dimensions making the gravity scale much lower are compatible with observations.
description: To appear in ApJ
A SIMPLE FRAMEWORK FOR DETERMINING THE FUNDAMENTAL AGRICULTURAL-USE VALUE OF MICHIGAN FARMLAND
Creators: name: Hanson, Steven D.
name: Hanson, Steven D.
Publisher: name: Unknown
Year: 1999
Subjects: Land Economics/Use

description: There is considerable interest in the determination of farmland values. Although alternative models exist, present value models have played a central role in recent studies of agricultural land markets. Alston (1986) uses a present value model to examine the effects of inflation and real growth in net rental income on farmland prices (see also Melichar, 1979). Present value models also underlie analysis of the dynamic behavior of farmland prices by Burt (1986); investigation of causality relations between farmland rents and prices by Phipps (1984); and analysis of the relationship between agricultural and nonagricultural land markets by Robison et al. (1985).
title: Iris (bulbeux) :
title: Principes directeurs pour la conduite de l’examen de la distinction, de l’homogénéité et de la stabilité.
titleType: Subtitle
Creators: name: International Union For The Protection Of New Varieties Of Plants,
Publisher: name: International Union for the Protection of New Varieties of Plants,
Year: 0
Subjects: Group identity.
New Varieties of Plants
Iris (bulbous)

description: Ces principes directeurs (“principes directeurs d’examen”) visent à approfondir les principes énoncés dans l’introduction générale (document TG/1/3) et dans les documents TGP qui s’y rapportent afin de donner des indications concrètes détaillées pour l’harmonisation de l’examen de la distinction, de l’homogénéité et de la stabilité (DHS) et, en particulier, à identifier des caractères convenant à l’examen DHS et à la production de descriptions variétales harmonisées.
Quantum phase transitions in an effective Hamiltonian: fast and slow systems
Creators: name: Sainz, Isabel
name: Klimov, Andrei B.
name: Roa, Luis
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: An effective Hamiltonian describing interaction between generic "fast" and a "slow" systems is obtained in the strong interaction limit. The result is applied for studying the effect of quantum phase transition as a bifurcation of the ground state of the "slow subsystem" in the thermodynamic limit. Examples as atom-field and atom-atom interactions are analyzed in detail.
The algebra of flat currents for the string on AdS_5 x S^5 in the light-cone gauge
Creators: name: Das, Ashok
name: Melikyan, A.
name: Sato, Matsuo
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We continue the program initiated in hep-th/0411200 and calculate the algebra of the flat currents for the string on AdS_5 x S^5 background in the light-cone gauge with kappa-symmetry fixed. We find that the algebra has a closed form and that the non-ultralocal terms come with a weight factor e^ϕ that depends on the radial AdS_5 coordinate. Based on results in two-dimensional sigma models coupled to gravity via the dilaton field, this suggests that the algebra of transition matrices in the present case is likely to be unambigous.
description: 27 pages, references added, version published in JHEP