cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
The dynamical modelling of dwarf spheroidal galaxies using Gaussian-process emulation
Creators: name: Gration, Amery
Publisher: name: University of Leicester
Year: 2020
Subjects: Uncategorized

description: This thesis concerns the use of Gaussian-process mulation (Sacks et al., 1989) to build metamodels of computationally expensive dynamical models of dwarf spheriodal galaxies. These metamodels are computationally cheaper to evaluate than the models that they emulate, and hence have the potential to render tractable previously intractable problems in galactic dynamics. The first part of the thesis deals with the theoretical foundations of Gaussian-process emulation (GPE) while the second part deals with the application of GPE to the modelling of dwarf spheroidal galaxies. I give a description of the general principles of modelling and metamodelling, formally defining a physical model, and showing that the parameter spaces of such models may be made metric or pseudometric spaces. I give a formal treatment of the foundations of GPE and, building on the work of Parzen (1959), give a novel derivation of the GPE predictor and mean-squared error. I also set right some confusion and errors in the literature. In particular, I show that the GPE predictor presented by Rasmussen and Williams (2006) is biased. I quantify this bias, and discuss the circumstances under which it will be significant. In modelling dwarf spheroidal galaxies, I adopt the distribution-function approach, and use GPE to construct a metamodel of the log-likelihood. First, I construct a toy model of a dwarf spheroidal galaxy which I fit using synthetic data drawn from the same toy model. I maximize the log-likelihood using the method of efficient global optimization (Jones et al., 1998), finding that I am able to recover robust confidence regions for the parameter vector, galactic density, and velocity anisotropy with fewer than 100 model evaluations. Second, I construct a more general model. Although the resulting predictions are accurate, the metamodel fails validation, indicating that we may not trust the confidence regions associated with these predictions. We conclude that the usual simplifications made in implementing GPE render it inadequate for the task of predicting the log-likelihood in this case, and that we must consider more general methods.
DNA polymerase sequence analysis of bacteriophage, podoviridae
Creators: name: Reid, Karen E.
Publisher: name: University of British Columbia
Year: 2009

description: Our oceans are biologically complex systems that incorporate a collection of participants. The most abundant players, which are the bacteria and viruses, are invisible to the naked eye. Seawater typically contains about a million bacteria and 10 million viruses per millilitre. Despite the abundance of viruses in seawater, little is known about their composition or diversity. This dissertation presents the design and application of a new set of PCR primers created to target a subset of bacteriophages. Bacteriophages are the viral fraction that infect and propagate through living bacterial cells. They vary both in terms of their morphology and their genetic constituents. My work focused on the family Podoviridae, one of 3 bacteriophage families that share similar morphological characteristics. The most notable characteristics include an isometric capsid about 60 nm in diameter, and a short, stubby tail. Moreover, although this family has been extensively reported in transmission electron microscopy scans, this study is the first to obtain Podoviridae genetic information from marine viral communities. To have a sense of the level of diversity that this Family constitutes, I designed a set of primers targeting the DNA polymerase gene (pol). The gene is approximately 2.0 kb in length and the primers target a 1.2-1.4 kb region for amplification. Following product verification and method optimization, I turned my attention to analysing environmental samples. Seven environmental samples from the Straight of Georgia, British Columbia, and one sample from the Gulf of Mexico, within the Mississippi River plume, were selected. The amplified products generated from each sample were cloned and 20 clones for each were randomly chosen for genetic comparison. Restriction fragment length polymorphism (RFLP) and sequencing were the methods adopted for analysis. RFLP analysis revealed 29 distinct restriction patterns of DNA pol genetic variation. These patterns indicate that certain samples contain greater genetic diversity than others and also that podovirus communities within a site are more similar than between sites. Sequencing these restriction patterns revealed that at the nucleotide level, 17 sequences were at least 5% different from each other. DNA pol genes from environmental podoviruses are divergent from coliphage T7 and T3, and are more similar to the marine isolates Roseophage SIO1 and Cyanophage P60. These latest environmental sequences clustered into four groups, two of which contain no cultured representatives. Moreover, the results indicate that the marine podoviruses share a common ancestor with the coliphage lineage. The work presented in this dissertation is the first study to target and examine the genetic diversity of environmental Podoviridae.
An Assessment of Consumer Preferences for Strawberry Products
Creators: name: Bruchhaus, Michael N.
name: Hinson, Roger A.
name: Bruchhaus, Michael N.
name: Hinson, Roger A.
Publisher: name: Unknown
Year: 2005
Subjects: Consumer/Household Economics

description: California has exploited its production advantages and marketing efficiency to increase strawberry production at the expense of traditional production areas like Louisiana. Conjoint analysis is used to examine consumer's preferences for selected product attributes of fresh strawberries in Louisiana. Consumers put highest relative importance on brand/origin and, to a lesser degree, price.
Microscopic theory of cavity-confined monolayer semiconductors: polariton-induced valley relaxation and the prospect of enhancing and controlling the valley pseudospin by chiral strong coupling
Creators: name: Salij, Andrew
name: Tempelaar, Roel
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We apply a microscopic theory of exciton-polaritons in cavity-confined monolayer transition-metal dichalcogenides including both optical polarizations in the monolayer plane, allowing to describe how chiral cavity photons interact with the valley degrees of freedom of the active material. Upon polariton formation, the degenerate excitons inhabiting the two inequivalent valleys are shown to assume bonding and antibonding superpositions as a result of cavity-mediated intravalley interactions combined with intervalley Coulomb interactions. This is representative of a polariton-induced coherent mixing of the valley polarization. In combination with disorder, this mixing is prone to open a new valley relaxation channel which attains significance with increasing cavity coupling. Importantly, we show that optical cavities with an asymmetric reflectance of left- and right-handed circularly-polarized photons offer a considerably more robust platform to realize a conserved valley polarization, as the valley localization of excitons is reinstated by an asymmetric Rabi splitting which lifts their degeneracy. Moreover, we show this degeneracy lifting to allow for wavelength-selective access to the valley pseudospin by means of a polariton-induced chiral Stark effect, offering interesting opportunities for valleytronic applications.
description: 9 pages, 4 figures
Economics of Increased Beef Grader Accuracy
Creators: name: Ibarburu, Maro A.
name: Lawrence, John D.
name: Busby, Darrell
name: Ibarburu, Maro A.
name: Lawrence, John D.
name: Busby, Darrell
Publisher: name: Unknown
Year: 2007
Subjects: subject: cattle
subject: carcass grading
subject: accuracy
subject: economics of grading

description: Carcass data from more than 38,000 cattle was used to compare the called and measured yield grade in two different periods: before and after the slaughter plant incorporated another grader in the line to improve grading accuracy. The study shows that the graders accuracy significantly increased. The higher accuracy affected all yield grades, but most notably resulted in more called yield grade 4 and 5 carcasses. This analysis will develop insight of what will be the effect of instrument grading that will be more accurate than previously called grades.The results are expressed as the conditional distribution of the called yield grade for a given value of the measured yield grade. The pricing grid currently used by the industry was used to analyze the effect of the graders errors on the expected values of the premiums on both periods and by yield grade. The results show that the company has an incentive to improve accuracy of grading. Simulating the results of measured vs. called yield grade over prices at the time and a standard industry grid showed that the plant can benefit by $1.32 per head by increasing grading accuracy.
Quantum mechanics is about quantum information
Creators: name: Bub, Jeffrey
Publisher: name: arXiv
Year: 2004
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: I argue that quantum mechanics is fundamentally a theory about the representation and manipulation of information, not a theory about the mechanics of nonclassical waves or particles. The notion of quantum information is to be understood as a new physical primitive -- just as, following Einstein's special theory of relativity, a field is no longer regarded as the physical manifestation of vibrations in a mechanical medium, but recognized as a new physical primitive in its own right.
description: 17 pages, forthcoming in Foundations of Physics Festschrift issue for James Cushing. Revised version: some paragraphs have been added to the final section clarifying the argument, and various minor clarifying remarks have been added throughout the text
Impacts of Alternative Marketing Agreement Cattle Procurement Volumes on Packer Costs: Evidence from Plant-Level P&L Data
Creators: name: Koontz, Stephen R.
name: Muth, Mary K.
name: Lawrence, John D.
name: Koontz, Stephen R.
name: Muth, Mary K.
name: Lawrence, John D.
Publisher: name: Unknown
Year: 2007

description: It has been argued that access to captive supply cattle improve the economic efficiency of beef packing facilities. However, this argument has not been subject to hypothesis testing. This work models the cost efficiencies associated with captive supplies or cattle we refer to as being sourced through alternative marketing agreements (AMAs). We find that slaughter and processing costs are lower ceteris paribus for AMA cattle than for cash market cattle. We find that plants that slaughter cattle from AMA sources operate at higher monthly volumes ceteris paribus and lower average costs per head. And we find that plants that slaughter cattle from AMA sources have more predictable volumes ceteris paribus and have lower average costs per head. If AMAs were limited or prohibited then packing industry efficiency would be negatively impacted and that fed cattle prices would be negatively impacted.
On a homotopy relation between the 2-local geometry and the Bouc complex for the sporadic group Co3
Creators: name: Maginnis, John
name: Onofrei, Silvia
Publisher: name: arXiv
Year: 2005
Subjects: subject: Group Theory (math.GR)
subject: Algebraic Topology (math.AT)
subject: FOS: Mathematics
subject: 20G05 (Primary); 20C20, 51D20 (Secondary)

description: We study the homotopy relation between the standard 2-local geometry and the Bouc complex for the sporadic group Co3. We also give a result concerning the relative projectivity of the reduced Lefschetz module associated to the aformentioned 2-local geometry.
description: 20 pages
Economic Analysis of Pharmaceutical Technologies in Modern Beef Production
Creators: name: Lawrence, John D.
name: Ibarburu, Maro A.
name: Lawrence, John D.
name: Ibarburu, Maro A.
Publisher: name: Unknown
Year: 2007
Subjects: subject: cattle
subject: production cost
subject: growth promotants
subject: ionophores
subject: antibiotics
subject: parasite control
subject: beta-agonists

description: Cattle production is the largest single agricultural sector in the U.S. with cash receipts of $49.2 billion in 2005. Like the rest of agriculture cattle producers have adopted efficiency and quality improving technology to meet consumer demands for a safe, wholesome, and affordable food supply. This research uses meta analysis to combine over 170 research trials evaluating pharmaceutical technologies in the cow-calf, stocker, and feedlot segments of beef production. These results were used to estimate the farm level economic value of parasite control, growth promotant implants, sub-therapeutic antibiotics, ionophores, and beta agonists for the industry in 2005. The Food and Agriculture Policy Research Institute (FAPRI) model of U.S. agriculture was used to estimate the impact on beef production, price, and trade and the rest of agriculture if these pharmaceutical technologies were not available. Using 2005 prices and production levels the cost savings of the five pharmaceutical technologies evaluated was over $360 head over the lifetime of the animal. Selling prices would have to increase 36% to cover the increase in costs. The resulting industry would have a similar beef cow inventory, lower beef production, and higher prices from retail through to producers. However, the higher prices do not fully offset the higher cost of production. Some consumers are requesting “natural” or organically produced beef and a portion of consumers are willing to pay a premium for these products. However, if pharmaceutical technologies were not available in the US cost of production would rise forcing some producers and resources out of cattle production. The smaller industry and domestic beef supply, increased net beef imports, and higher prices to all consumers.
Meat Processors Purchasing and Sale Practices: Lessons Learned from the GIPSA Livestock and Meat Marketing Study
Creators: name: Lawrence, John D.
name: Muth, Mary K.
name: Taylor, Justin
name: Koontz, Stephen R.
name: Lawrence, John D.
name: Muth, Mary K.
name: Taylor, Justin
name: Koontz, Stephen R.
Publisher: name: Unknown
Year: 2007
Subjects: subject: Downstream meat marketing
subject: alternative marketing arrangements
subject: supply chain

description: The meat value chain is a complex organization with multiple participants performing numerous value added functions. Perhaps the most complex and least well understood segment is that downstream from the packer, e.g., the processor, wholesaler, exporter, retailer and food service (or restaurant) operator. One portion of the Livestock and Meat Marketing Study provided an overview of marketing and pricing methods used in this sector and, in particular, the results of analyses of the relationship between use of alternative marketing arrangements (AMAs) and the distribution and sales of meat products downstream from the packer. The analyses include both beef and pork products, are descriptive and focus on the relationships among industry articipants beyond the packing plant. The information used includes the results of the industry interviews, data from the industry surveys, and transactions data from meat processors. Primary conclusions related to meat processing, distribution, and sales, are as follows: • Firms differ greatly in the sales, purchase, and pricing methods for meat. Firms rely heavily on the spot market but also use other methods. They also mix-and-match purchase and pricing methods, e.g., buying on the forward market, but pricing on a formula. • Meat processors play an important distribution role in the meat value chain by purchasing large lots from a few sources and selling small lots to many firms. • Packers sort cattle purchased under various marketing arrangements to meet the needs of its buyers, but aggregate transactions data suggest that downstream marketing arrangements have little or no relationship to cattle purchase methods or branded beef sales programs.
The Impact of Small-Scale Structure on Cosmological Ionization Fronts and Reionization
Creators: name: Iliev, Ilian T.
name: Scannapieco, Evan
name: Shapiro, Paul R.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The propagation of cosmological ionization fronts during the reionization of the universe is strongly influenced by small-scale gas inhomogeneities due to structure formation. These inhomogeneities include both collapsed minihalos, which are generally self-shielding, and lower-density structures, which are not. The minihalos are dense and sufficiently optically-thick to trap intergalactic ionization fronts, blocking their path and robbing them of ionizing photons until the minihalo gas is expelled as an evaporative wind. The lower-density structures do not trap these fronts, but they can slow them down by increasing the overall recombination rate in the intergalactic medium. In this paper we study the effects of both types of inhomogeneities, including nonlinear clustering effects, and we find that both IGM clumping and collapsed minihalos have significant yet qualitatively different impacts on reionization. While the number density of minihalos on average increases strongly with time, the density of minihalos inside H II regions around ionizing sources is largely constant. Thus the impact of minihalos is essentially to decrease the number of ionizing photons available to the IGM at all epochs, which is equivalent to a reduction in the luminosity of each source. On the other hand, the effect of IGM clumping increases strongly with time, slowing down reionization and extending it. Thus while the impact of minihalos is largely degenerate with the unknown source efficiency, IGM clumping can help significantly in reconciling the recent observations of cosmic microwave background polarization with quasar absorption spectra at z~6, which together point to an early but extended reionization epoch.
description: 15 pages, 9 figures, minor revisions to respond to referee comments, accepted for publication in The Astrophysical Journal
Neural Network for Low-Memory IoT Devices and MNIST Image Recognition Using Kernels Based on Logistic Map
Creators: name: Velichko, Andrei
Publisher: name: arXiv
Year: 2020
Subjects: subject: Neural and Evolutionary Computing (cs.NE)
subject: Emerging Technologies (cs.ET)
subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: This study presents a neural network which uses filters based on logistic mapping (LogNNet). LogNNet has a feedforward network structure, but possesses the properties of reservoir neural networks. The input weight matrix, set by a recurrent logistic mapping, forms the kernels that transform the input space to the higher-dimensional feature space. The most effective recognition of a handwritten digit from MNIST-10 occurs under chaotic behavior of the logistic map. The correlation of classification accuracy with the value of the Lyapunov exponent was obtained. An advantage of LogNNet implementation on IoT devices is the significant savings in memory used. At the same time, LogNNet has a simple algorithm and performance indicators comparable to those of the best resource-efficient algorithms available at the moment. The presented network architecture uses an array of weights with a total memory size from 1 to 29 kB and achieves a classification accuracy of 80.3-96.3%. Memory is saved due to the processor, which sequentially calculates the required weight coefficients during the network operation using the analytical equation of the logistic mapping. The proposed neural network can be used in implementations of artificial intelligence based on constrained devices with limited memory, which are integral blocks for creating ambient intelligence in modern IoT environments. From a research perspective, LogNNet can contribute to the understanding of the fundamental issues of the influence of chaos on the behavior of reservoir-type neural networks.
description: 17 pages, 7 figures, 2 tables, 1 Appendix
Information Content in Deferred Futures Prices: Live Cattle and Hogs
Creators: name: Sanders, Dwight R.
name: Garcia, Philip
name: Manfredo, Mark R.
name: Sanders, Dwight R.
name: Garcia, Philip
name: Manfredo, Mark R.
Publisher: name: Unknown
Year: 2007
Subjects: subject: forecast information
subject: forecast evaluation
subject: livestock futures

description: The marginal forecast information contained in deferred futures prices is evaluated using the direct test of Vuchelen and Gutierrez. In particular, the informational role of deferred futures contracts in live cattle and hogs is assessed from the two- to twelve-month horizons. The results indicate that unique information is contained in live cattle futures prices out through the ten-month horizon, while hog futures prices add incremental information at all tested horizons. Practitioners using futures-based forecasting methods are well-served by deferred hog futures prices; however, live cattle futures listed beyond the 10 month horizon are not adding incremental information.
Giới thiệu: Hướng dẫn triển khai khung năng lực số cho công dân (DigComp) ở nơi làm việc
Creators: name: Nghia, Lê Trung
Publisher: name: Zenodo
Year: 2024

description: Bài trình chiếu để sử dụng trong các cuộc hội thảo/tọa đàm/khóa tập huấn về chủ đề chuyển đổi số và/hoặc các khung năng lực số, đặc biệt có liên quan đến Khung năng lực số cho công dân (DigComp) của châu Âu.
Do Big Crops Get Bigger and Small Crops Get Smaller? Further Evidence on Smoothing in USDA Crop Production Forecasts
Creators: name: Isengildina-Massa, Olga
name: Irwin, Scott H.
name: Good, Darrel L.
name: Isengildina-Massa, Olga
name: Irwin, Scott H.
name: Good, Darrel L.
Publisher: name: Unknown
Year: 2007
Subjects: subject: corn
subject: crop production
subject: forecasts
subject: smoothing
subject: soybeans
subject: USDA

description: The purpose of this paper is to determine whether smoothing in USDA corn and soybean production forecasts is concentrated in years with relatively small and large crops. The sample consists of all USDA corn and soybean production forecasts released over the 1970 through 2006 crop years. Results show that USDA crop production forecasts in both corn and soybeans have a marked tendency to decrease in small crop years and increase in big crop years. The magnitude of smoothing is surprisingly large, with corn and soybean production forecasts cumulatively revised downward by about 6 to 7 percent in small crop years and upward by about 5 to 6 percent in large crop years. Crop condition ratings are useful in predicting whether the current year is likely to be a small, normal, or big crop year. Hence, there appears to be an opportunity for the USDA to incorporate additional information into the forecasting process to reduce or eliminate the smoothing inherent in different types of crop years.
Quantum fluctuations hinder finite-time information erasure near the Landauer limit
Creators: name: Miller, Harry J. D.
name: Guarnieri, Giacomo
name: Mitchison, Mark T.
name: Goold, John
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Information is physical but information is also processed in finite time. Where computing protocols are concerned, finite-time processing in the quantum regime can dynamically generate coherence. Here we show that this can have significant thermodynamic implications. We demonstrate that quantum coherence generated in the energy eigenbasis of a system undergoing a finite-time information erasure protocol yields rare events with extreme dissipation. These fluctuations are of purely quantum origin. By studying the full statistics of the dissipated heat in the slow driving limit, we prove that coherence provides a non-negative contribution to all statistical cumulants. Using the simple and paradigmatic example of single bit erasure, we show that these extreme dissipation events yield distinct, experimentally distinguishable signatures.
description: 5+13 pages, 3+2 figures. Comments welcome. v2: Minor changes to text; updated Fig. 1, bibliography and links. v3: Final author version
Universal Aspects of Coulomb Frustrated Phase Separation
Creators: name: Jamei, Reza
name: Kivelson, Steven
name: Spivak, Boris
Publisher: name: arXiv
Year: 2004
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study the consequences of Coulomb interactions on a system undergoing a putative first order phase transition. In two dimensions (2D), near the critical density, the system is universally unstable to the formation of new intermediate phases, which we call ``electronic microemulsion phases,'' which consist of an intermediate scale mixture of regions of the two competing phases. A correlary is that there can be no direct transition as a function of density from a 2D Wigner crystal to a uniform electron liquid. In 3D, %we find that if the strength of the Coulomb interactions exceeds a critical value, no phase separation occurs, while for weaker Coulomb strength, electronic microemulsions are inevitable. This tendency is considerably more pronounced in anisotropic (quasi 2D or quasi 1D) systems, where a devil's staircase of transitions is possible.
description: 4 pgs
The Cattle Price Cycle: An Exploration in Simulation
Creators: name: Stockton, Matthew C.
name: Van Tassell, Larry W.
name: Stockton, Matthew C.
name: Van Tassell, Larry W.
Publisher: name: Unknown
Year: 2007
Subjects: subject: cattle Price cycle
subject: harmonic model
subject: simulation

description: The simulation of commodity prices has been undertaken using a myriad of techniques, with some omitting the cyclical component and others ignoring the presence of inter-temporal relationships expressed as autoregressive errors. This study examines the periodicity of cattle prices and the modeling of the cattle cycle for simulation purposes. The AIC criterion is used to determine lengths of various cycles to be included in a harmonic model, with a chained modeling approach providing the best representation of the cattle cycle.
The Effect of Ethanol Production on the U.S. National Corn Price
Creators: name: Park, Hwanil
name: Fortenbery, T. Randall
name: Park, Hwanil
name: Fortenbery, T. Randall
Publisher: name: Unknown
Year: 2007
Subjects: subject: corn price
subject: ethanol
subject: simultaneous equations
subject: three-state least squares
subject: elasticity

description: A system of equations representing corn supply, feed demand, export demand, food, alcohol and industrial (FAI) demand, and corn price is estimated by three-stage least squares. A price dependent reduced form equation is then formed to investigate the effect of ethanol production on the national average corn price. The elasticity of corn price with respect to ethanol production is then obtained. Results suggest that ethanol production has a positive impact on the national corn price and that the demand from FAI has a greater impact on the corn price than other demand categories. Thus, significant growth in ethanol production is important in explaining corn price determination.
Archäologische Miszellen aus Ägypten
Creators: name: Kaufmann, Carl Maria
Publisher: name: Oriens christianus : Hefte für die Kunde des christlichen Orients
Year: 2024

description: Oriens christianus : Hefte für die Kunde des christlichen Orients, Bd. 11 Nr. 2 (1913): Oriens christianus, Band 11, Heft 2
Issues and Strategies for Aggregate Supply Response Estimation for Policy Analyses
Creators: name: Ramirez, Octavio A.
name: Mohanty, Samarendu
name: Carpio, Carlos E.
name: Denning, Megan
name: Ramirez, Octavio A.
name: Mohanty, Samarendu
name: Carpio, Carlos E.
name: Denning, Megan
Publisher: name: Unknown
Year: 2004
Subjects: subject: nonnormality
subject: probability distribution function
subject: supply response

description: We demonstrate the use of the small-sample econometrics principles and strategies to come up with reliable yield and acreage models for policy analyses. We focus on demonstrating the importance of proper representation of systematic and random components of the model for improving forecasting precision along with more reliable confidence intervals for the forecasts. A probability distribution function modeling approach, which has been shown to provide more reliable confidence intervals for the dependent variable forecasts than the standard models that assume error term normality, is used to estimate cotton supply response in the Southeastern United States.
Evolving small-world networks with geographical attachment preference
Creators: name: Zhang, Zhongzhi
name: Rong, Lili
name: Comellas, Francesc
Publisher: name: arXiv
Year: 2005
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We introduce a minimal extended evolving model for small-world networks which is controlled by a parameter. In this model the network growth is determined by the attachment of new nodes to already existing nodes that are geographically close. We analyze several topological properties for our model both analytically and by numerical simulations. The resulting network shows some important characteristics of real-life networks such as the small-world effect and a high clustering.
description: 11 pages, 4 figures
Pair separation in parallel electric field in magnetar magnetosphere and narrow spectra of fast radio bursts
Creators: name: Yang, Yuan-Pei
name: Zhu, Jin-Ping
name: Zhang, Bing
name: Wu, Xue-Feng
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: When the magnetosphere of a magnetar is perturbed by crustal deformation, an electric field $E_\parallel$ parallel to the magnetic field line would appear via Alvfén waves in the charge starvation region. The electron-positron pair bunches will be generated via two-stream instability in the magnetosphere, and these pairs will undergo charge separation in the $E_\parallel$ and in the meantime emit coherent curvature radiation. Following the approach of Yang & Zhang (2018), we find that the superposed curvature radiation becomes narrower due to charge separation, with the width of spectrum depending on the separation between the electron and positron clumps. This mechanism can interpret the narrow spectra of FRBs, in particular, the spectrum of Galactic FRB 200428 recently detected in association with a hard X-ray burst from the Galactic magnetar SGR J1935+2154.
description: 7 pages, 3 figures, accepted for publication in ApJL
Solving the Fokker-Planck kinetic equation on a lattice
Creators: name: Moroni, Daniele
name: Rotenberg, Benjamin
name: Hansen, Jean-Pierre
name: Succi, Sauro
name: Melchionna, Simone
Publisher: name: arXiv
Year: 2005
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We propose a discrete lattice version of the Fokker-Planck kinetic equation along lines similar to the Lattice-Boltzmann scheme. Our work extends an earlier one-dimensional formulation to arbitrary spatial dimension $D$. A generalized Hermite-Gauss procedure is used to construct a discretized kinetic equation and a Chapman-Enskog expansion is applied to adapt the scheme so as to correctly reproduce the macroscopic continuum equations. The stability of the algorithm with respect to the finite time-step $Δt$ is characterized by the eigenvalues of the collision matrix. A heuristic second-order algorithm in $Δt$ is applied to investigate the time evolution of the distribution function of simple model systems, and compared to known analytical solutions. Preliminary investigations of sedimenting Brownian particles subjected to an orthogonal centrifugal force illustrate the numerical efficiency of the Lattice-Fokker-Planck algorithm to simulate non-trivial situations. Interactions between Brownian particles may be accounted for by adding a standard BGK collision operator to the discretized Fokker-Planck kernel.
description: 21 pages, 6 figures, submitted to Phys. Rev. E
Conductive Paintable 2D Layered MoS2 Inks
Creators: name: Carroll, Elaine
name: Buckley, Darragh
name: McNulty, David
name: O'Dwyer, Colm
Publisher: name: arXiv
Year: 2020
Subjects: subject: Applied Physics (physics.app-ph)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Conductive and paintable inks of 2D layered MoS2 with aspect ratio-dependent conductivity are demonstrated. Using ultrasonically assisted solvent-exfoliation of MoS2, high concentration 2D and few-layer suspensions become inks that provide coherent films when painted. Conductivity of paintable 2D MoS2 inks can be modulated by length and width, where the conductivity is linked to the painting direction. Reducing the painted film width, increases conductivity for similar length, and the films conductivity is aspect ratio-dependent. Inks of solvent-exfoliated 2D MoS2 can be painted without polymeric additives.
description: 11 pages, 4 figures
Buyback Programs: Goals, Objectives, and Industry Restructuring in Fisheries
Creators: name: Kirkley, James E.
name: Walden, John B.
name: Waters, James R.
name: Kirkley, James E.
name: Walden, John B.
name: Waters, James R.
Publisher: name: Unknown
Year: 2004
Subjects: subject: capacity utilization
subject: Data Envelopment Analysis
subject: fishery buyback programs
subject: fishing capacity

description: National Oceanic and Atmospheric Administration Fisheries has conducted several buyback programs to reduce harvesting capacity in fisheries. These programs have attempted to maximize capacity reduction given a fixed budget. However, restructuring issues have not been considered. We explore the possibility of satisfying three different buyback objective We examine the black sea bass trap fishery and determine the number of vessels given different allowable catch levels and objectives of maximizing technical efficiency, capacity utilization, and vessels in the fishery. We find considerable variation in the number of vessels allowed to remain in the fishery given the different objectives.
The Disk Atmospheres of Three Herbig Ae/Be Stars
Creators: name: Harker, David E.
name: Woodward, Charles E.
name: Wooden, Diane H.
name: Temi, Pasquale
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present infrared (IR) spectrophotometry ($R \simeq 180$) of three Herbig Ae/Be stars surrounded by possible protoplanetary disks: HD 150193, HD100546 and HD 179218. We construct a mid-IR spectral energy distributions (SED) for each object by using $7.6 - 13.2$ \micron HIFOGS spectra, 2.4 -- 45 \micron\ spectrophotometry from the {\it ISO} SWS, the 12, 25, 60, and 100 \micron\ photometric points from IRAS, and for HD 179218, photometric bolometric data points from the Mt. Lemmon Observing Facility. The SEDs are modeled by using an expanded version of the \citet{chigol97} two-layer, radiative and hydrostatic equilibrium, passive disk. This expanded version includes the emission from Mg-pure crystalline olivine (forsterite) grains in the disk surface layer. HD 150193 contains no crystals while HD 100546 and HD 179218 respectively show evidence of having crystalline silicates in the surface layers of their disks. We find that the inner region of HD100546 has a 37% higher crystalline-to-amorphous silicate ratio in its inner disk region ($\leq 5$ AU) compared to the outer disk region, while the inner disk region of HD 179218 has a 84% higher crystalline-to-amorphous silicate ratio in its inner disk region ($\leq 5$ AU) compared to the outer region. HD 150193 is best-fit by a small disk ($\sim 5$ AU in radius) while HD 100546 and HD 179218 are best fit by larger disks ($\sim 150$ AU in radius).
description: 20 pages, 5 figures
Buyback Programs for Capacity Reduction in the U.S. Atlantic Shark Fishery
Creators: name: Larkin, Sherry L.
name: Keithly, Walter R.
name: Adams, Charles M.
name: Kazmierczak, Richard F.
name: Larkin, Sherry L.
name: Keithly, Walter R.
name: Adams, Charles M.
name: Kazmierczak, Richard F.
Publisher: name: Unknown
Year: 2004
Subjects: subject: buyback programs
subject: fishing capacity
subject: fishing permits
subject: latent permits
subject: marine fisheries
subject: vessel decommissioning schemes

description: Declining fishery stocks, increasing fishing effort and adverse market conditions have produced difficult financial situations for fishermen worldwide. Several high-valued fisheries are considered to be overcapitalized. The purchase and permanent retirement of fishing vessels and/or permits under a buyback program is one approach for reducing fishing capacity. Evidence from previous programs, however, suggests that buybacks are not a panacea for solving overcapacity problems. Whether such programs can help rebuild stocks and improve the financial condition of fleets in any specific fishery depends on a multitude of factors. We consider the potential of a buyback program for the U.S. Atlantic shark fishery.
WIYN/Hydra Detection of Lithium Depletion in F Stars of the Young Open Cluster M35 and Implications for the Development of the Lithium Gap
Creators: name: Steinhauer, Aaron
name: Deliyannis, Constantine P.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report discovery of significant depletion of Li on the surfaces of F dwarf stars in the 150-Myr-old open cluster M35, analagous to a feature in the 700-Myr-old Hyades cluster that has been referred to as the ``Li gap.'' We have caught the gap in the act of forming: using high resolution, high S/N, WIYN/Hydra observations, we detect Li in all but a few M35 F stars; the maximum depletion lies at least 0.6-0.8 dex below minimally depleted (or undepleted) stars. The M35 Li depletion region, a) is quite wide, with clear depletion seen from 6000K to 6700K or hotter; b) shows a significant dispersion in Li abundance at all T_eff, even with stars of the same T_eff; and c) contains undepleted stars (as well as depleted ones) in the (narrow) classical Hyades gap region, which itself shows no undepleted stars. All of these M35 Li depletion properties support rotationally-induced slow mixing as the primary physical mechanism that forms the gap, and argues against other proposed mechanisms, particularly diffusion and steady main sequence mass loss. When viewed in the context of the M35 Li depletion properties, the Hyades Li gap may well be wider than is usually recognized.
description: 14 Pages, 3 figures. Accepted to ApJ Letters
Revealing the Atomic Site-Dependent g Factor within a Single Magnetic Molecule via the Extended Kondo Effect
Creators: name: Liu, Liwei
name: Yang, Kai
name: Jiang, Yuhang
name: Song, Boqun
name: Xiao, Wende
name: Song, Shiru
name: Du, Shixuan
name: Ouyang, Min
name: Hofer, Werner A.
name: Neto, Antonio H. Castro
name: Gao, Hong-Jun
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The site-dependent g factor of a single magnetic molecule, with intramolecular resolution, is demonstrated for the first time by low-temperature, high-magnetic-field scanning tunneling microscopy of dehydrogenated Mn-phthalocyanine molecules on Au(111). This is achieved by exploring the magneticfield dependence of the extended Kondo effect at different atomic sites of the molecule. Importantly, an inhomogeneous distribution of the g factor inside a single molecule is revealed. Our results open up a new route to access local spin properties within a single molecule.
Assessing the accuracy of the GENIE event generator with electron-scattering data
Creators: name: Ankowski, Artur M.
name: Friedland, Alexander
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Precision neutrino oscillation experiments of the future---of which DUNE is a prime example---require reliable event generator tools. The 1--4 GeV energy regime, in which DUNE will operate, is marked by the transition from the low-energy nuclear physics domain to that of perturbative QCD, resulting in rich and highly complex physics. Given this complexity, it is important to establish a validation procedure capable of disentangling the physical processes and testing each of them individually. Here, we demonstrate the utility of this approach by benchmarking the GENIE generator, currently used by all Fermilab-based experiments, against a broad set of inclusive electron-scattering data. This comparison takes advantage of the fact that, while electron-nucleus and neutrino-nucleus processes share a lot of common physics, electron scattering gives one access to precisely known beam energies and scattering kinematics. Exploring the kinematic parameter range relevant to DUNE in this manner, we observe patterns of large discrepancies between the generator and data. These discrepancies are most prominent in the pion-producing regimes and are present not only in medium-sized nuclei, including argon, but also in deuterium and hydrogen targets, indicating mismodeled hadronic physics. Several directions for possible improvement are discussed.
description: 22 pages, 20 figures, matches the published version
Polymer-encapsulated organic nanocrystals for single photon emission
Creators: name: Schofield, Ross C.
name: Bogusz, Dominika P.
name: Hoggarth, Rowan A.
name: Nur, Salahuddin
name: Major, Kyle D.
name: Clark, Alex S.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optics (physics.optics)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We demonstrate an emulsion-polymerisation technique to embed dibenzoterrylene-doped anthracene nanocrystals in polymethyl methacrylate (PMMA) nanocapsules. The nanocapsules require no further protection after fabrication and are resistant to sublimation compared to unprotected anthracene. The room temperature emission from single dibenzoterrylene molecules is stable and when cooled to cryogenic temperatures we see no change in their excellent optical properties compared to existing growth methods. These now robust nanocapsules have potential for surface functionalisation and integration into nanophotonic devices, where the materials used are compatible with incorporation in polymer-based designs.
description: 8 pages, comments welcome
Constraining Reionization with the Evolution of the Luminosity Function of Lyman Alpha mitting Galaxies
Creators: name: Haiman, Zoltan
name: Cen, Renyue
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: At redshifts beyond z>6, as the mean fraction of neutral hydrogen x_HI in the intergalactic medium (IGM) increases, the line flux of Lyman alpha (Lya) emitters can be significantly suppressed, which can result in a decrease in the observed number of emitters at a given Lya flux. However, cosmological HII regions surrounding the Lya emitting galaxies alleviate these effects. We use simple models of the Lya line suppression that incorporate the presence of HII regions to predict the overall effect of the Lya absorption on the Lya luminosity function. We find, in agreement with other recent studies, that unless ionizing sources are unusually strongly clustered, a fully neutral IGM may be inconsistent with the large abundance of confirmed z=6.5 Lya emitters. However, the presence of local HII regions prohibits placing a tight constraint on the mean neutral fraction. We find x_HI < 0.25; the presence of strong winds and/or the clustering of ionizing sources would further weaken this constraint. We conclude that the evolution of the Lya LF is consistent with reionization occurring near this redshift. Finally, we suggest that a measurement of observed Lya line width as a function of the Lya luminosity, in a future, larger sample of Lya emitters, may serve as a robust diagnostic of the neutral fraction in the IGM.
description: 4 emulateapj pages, 4 figures, submitted to ApJ Letters
Measurement and Explanation of Technical Efficiency Performance in Ukrainian Agriculture, 1991-1996
Creators: name: Murova, Olga I.
name: Trueblood, Michael A.
name: Coble, Keith H.
name: Murova, Olga I.
name: Trueblood, Michael A.
name: Coble, Keith H.
Publisher: name: Unknown
Year: 2004
Subjects: subject: Data envelopment analysis
subject: enterprise privatization
subject: inefficiency
subject: price liberalization
subject: productivity
subject: stochastic frontier analysis
subject: technical efficiency

description: The present study examines technical efficiency patterns in Ukraine’s crop sector for 1991-1996. The economic and policy environment in Ukraine has changed since reform began in 1991. Many policy changes have exerted offsetting economic pressures on efficiency. Enterprise privatization and the liberalization of prices and trade put upward pressure on technical efficiency, whereas start-stop land privatization efforts, unpredictable government intervention, and slow developments in the credit and labor markets put downward pressure on efficiency. We found that technical efficiency appears to have improved slightly over the 1991-1996 period, suggesting that the positive forces had more impact.
Kinetic energy change with doping upon superfluid condensation in high temperature superconductors
Creators: name: Deutscher, G.
name: Santander-Syro, A. F.
name: Bontemps, N.
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 conventional BCS superconductors, the electronic kinetic energy increases upon superfluid condensation (the change DEkin is positive). Here we show that in the high critical temperature superconductor Bi-2212, DEkin crosses over from a fully compatible conventional BCS behavior (DEkin>0) to an unconventional behavior (DEkin<0) as the free carrier density decreases. If a single mechanism is responsible for superconductivity across the whole phase diagram of high critical temperature superconductors, this mechanism should allow for a smooth transition between such two regimes around optimal doping.
description: 3 pages, 2 figures