cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Circumstellar discs around solar-mass stars in NGC 6611
Creators: name: Oliveira, J. M.
name: Jeffries, R. D.
name: van Loon, J. Th.
name: Littlefair, S. P
name: Naylor, T.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We have performed IZJHKL' observations in NGC 6611, the young cluster that ionises the Eagle Nebula. We have discovered a rich pre-main sequence concentrated around the O-stars in the cluster. As measured by their L'-band excesses, at least 58% +/- 5% of the pre-main sequence objects (0.45 Msun < M < 2 Msun) have circumstellar discs. By comparing this disc frequency with frequencies determined for regions where the pre-main sequence stars are subject to less ionising radiation, we find no evidence that the harsher environment of NGC 6611 (approximately an order of magnitude more ionising Lyman continuum radiation than the Trapezium cluster) significantly hastens the dissipation of circumstellar discs around solar-mass stars.
description: 4 pages, 3 figures, accepted for publication by MNRAS letters
Do Pesticide Hazards to Human Health and Beneficial Insects Cause or Result from IPM Adoption? Mixed Messages from Farmer Field Schools in Nicaragua
Creators: name: Labarta, Ricardo A.
name: Swinton, Scott M.
name: Labarta, Ricardo A.
name: Swinton, Scott M.
Publisher: name: Unknown
Year: 2005
Subjects: subject: Farm Management
subject: ecosystem service
subject: integrated pest management
subject: agricultural extension
subject: Nicaragua

description: This paper analyzes the interaction between farmer training in pest management and effects on acute pesticide poisoning and populations of beneficial insects in Nicaragua. Using farm level data from Nicaraguan bean growers, including graduates of Farmer Field Schools (FFS), other integrated pest management (IPM) outreach methods, and farmers without exposure to IPM, we found that small farmers are influenced by pesticide-related acute illness experiences when adopting IPM practices and making decisions about pesticide use. However, exposure to IPM extension programs failed to reduce the use of highly toxic pesticides and increased the number of self-reported acute illness symptoms during the most recent bean crop season. IPM training did result in growth of beneficial insect populations.
Why Doesn't Africa Trade Regionally?
Creators: name: Mitchell, Lorraine
name: Mitchell, Lorraine
Publisher: name: Unknown
Year: 2005
Subjects: International Relations/Trade

description: African countries do not tend to trade agricultural goods regionally, in contrast to other regions of the world. The current research uses a gravity model to consider several alternative hypotheses for this stylized fact. The results indicate that African countries tend to trade with countries that have similar diets, but also with countries that have comparative advantage in production and similar languages. Being landlocked reduces trade likelihood, but African countries seem similarly or more likely to import from bordering countries than nations in general. The model also overpredicts trade for most observations but underpredicts imports from middle income African importers.
Analysis of Grain Supply Chain Performance Based on Relative Impact of Channel Coordinator's Objectives on Firm Level Objectives
Creators: name: Baiyee-Mbi, Agbor-Baiyee
name: Mazzocco, Michael A.
name: Baiyee-Mbi, Agbor-Baiyee
name: Mazzocco, Michael A.
Publisher: name: Unknown
Year: 2005
Subjects: Industrial Organization

description: A fuzzy multi-objective programming model is used to analyze the optimal decisions in a multi-objective grain supply chain in which the firm-level firm goals are conflicting with the channel coordinator's goals. The relative impact of the channel coordinator's goals on performance of the supply chain is determined through a linear weighting method. The study finds that prioritizing the channel coordinator's goals enhances the overall performance of the system.
Spatial Evidence for Transition Radiation in a Solar Radio Burst
Creators: name: Nita, Gelu M.
name: Gary, Dale E.
name: Fleishman, Gregory D.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Microturbulence, i.e. enhanced fluctuations of plasma density, electric and magnetic fields, is of great interest in astrophysical plasmas, but occurs on spatial scales far too small to resolve by remote sensing, e.g., at ~ 1-100 cm in the solar corona. This paper reports spatially resolved observations that offer strong support for the presence in solar flares of a suspected radio emission mechanism, resonant transition radiation, which is tightly coupled to the level of microturbulence and provides direct diagnostics of the existence and level of fluctuations on decimeter spatial scales. Although the level of the microturbulence derived from the radio data is not particularly high, /n^2 ~ 10^{-5}$, it is large enough to affect the charged particle diffusion and give rise to effective stochastic acceleration. This finding has exceptionally broad astrophysical implications since modern sophisticated numerical models predict generation of much stronger turbulence in relativistic objects, e.g., in gamma-ray burst sources.
description: 13 pages, 4 figures, ApJL accepted
Testing Speculative Behavior in Farmland Demand
Creators: name: Barton, Nick
name: Adelaja, Adesoji O.
name: Seedang, Saichon
name: Barton, Nick
name: Adelaja, Adesoji O.
name: Seedang, Saichon
Publisher: name: Unknown
Year: 2005
Subjects: Land Economics/Use

description: Substantial increases in farmland demand in sub-urbanization have had profound effects on agriculture and produced a surge in farmland values. With escalating land values, farmland can take on the characteristics of a speculative asset and farmland owners may be more responsive to the investment value of farmland than the productive value. Speculation has been shown to have a significant impact on the agricultural production decisions of farms, and may encourage farmers to curtail capital investments and prematurely idle productive farmland. This paper investigates the effects of farmland value appreciation on agriculture and isolates the speculative component of land use demand, using New Jersey as a case study. A conceptual model of land use and investment behavior is developed and estimated. Two empirical models are used in the analysis; one that accounts for speculation and one that does not. The former is found to be superior. An inverse relationship is estimated between the rate of appreciation and the demand for farmland, suggesting a direct relationship between appreciation and land supplied to development. The relationship, however, is found to be positive at rates of farmland value appreciation in excess of the risk free rate of return. This suggests an identifiable speculative demand component whereby farmland owners retain farmland at high rates of appreciation. Results also support the conjecture that when the rate of appreciation is lower than the risk free rate, the speculative behavior of farmland owners is to keep less land in agriculture.
Experimental study of effectiveness of nonpoint source water pollution control group contract.
Creators: name: Pushkarskaya, Helen N.
name: Arkes, Hal
name: Pieratt, Jason
name: Bamba, Ibrahim
name: Pushkarskaya, Helen N.
name: Arkes, Hal
name: Pieratt, Jason
name: Bamba, Ibrahim
Publisher: name: Unknown
Year: 2005
Subjects: Environmental Economics and Policy

description: The goal of this experimental study was to test an effectiveness of a group contract designed to control nonpoint source water pollution from farms' runoff (Pushkarskaya 2003). In particular, the regulator pays for pollution reduction credits earned by the group of the farmers, who voluntary enter the contract, and is concerned only with the total level of the abatement achieved, while the group of farmers undertakes responsibility to distribute the payment so as to induce the farmers to deliver the desired level of abatement. First round of experiments was conducted using as subjects undergraduate students from the Ohio State University, second round of experiments was conducted using as a subjects Kentucky farmers, who would be an actual subjects to this policy if it is ever implemented. Experiments with farmers can be considered as an intermediate step between traditional experiments with undergraduate students and field experiments. Results of these experiments suggest, in contrast to common believes among environmental economists, that uncertainty, associated with diffusive nature of nonpoint source water pollution, not only does not affect negatively farmers' participation in the program, but also might play a positive role in promoting a cooperation within a group.
The maximum entropy ansatz in the absence of a time arrow: fractional pole models
Creators: name: Georgiou, Tryphon T.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Probability (math.PR)
subject: Optimization and Control (math.OC)
subject: FOS: Mathematics
subject: 60G10

description: The maximum entropy ansatz, as it is often invoked in the context of time-series analysis, suggests the selection of a power spectrum which is consistent with autocorrelation data and corresponds to a random process least predictable from past observations. We introduce and compare a class of spectra with the property that the underlying random process is least predictable at any given point from the complete set of past and future observations. In this context, randomness is quantified by the size of the corresponding smoothing error and deterministic processes are characterized by integrability of the inverse of their power spectral densities--as opposed to the log-integrability in the classical setting. The power spectrum which is consistent with a partial autocorrelation sequence and corresponds to the most random process in this new sense, is no longer rational but generated by finitely many fractional-poles.
description: 18 pages, 3 figures
Cheap Food Policy: Fact or Rhetoric?
Creators: name: Miller, James C.
name: Coble, Keith H.
name: Miller, James C.
name: Coble, Keith H.
Publisher: name: Unknown
Year: 2005
Subjects: Agricultural and Food Policy

description: The term "cheap food policy" has frequently been used as a descriptor for U.S. commodity programs by those who contend these payments to farmers ultimately result in lower food costs for consumers. More recently, farm policy has been criticized for contributing to the obesity problem in the U.S. by making large quantities of fattening foods widely available and relatively inexpensive. This paper econometrically evaluates the impact of direct government payments to farmers from 1960-1999 on the proportion of disposable income consumers spend on food. The model finds the payments do not significantly affect the affordability of food.
Lilje, Hanns (Hrsg.) / ..., Das Buch der Spirituals und Gospel Songs
Creators: name: Krüger
Publisher: name: Ökumenische Rundschau
Year: 2025

description: Ökumenische Rundschau, Bd. 11 Nr. 2 (1962): Ökumenische Rundschau, Band 11, Heft 2
Finite element model for cyclic loading of concrete filled steel tube pile
Creators: name: Park, Min Young
Publisher: name: University of British Columbia
Year: 2009

description: A non-linear finite element analysis is presented to predict the lateral response of a concrete-filled steel tube (CFT) pile subjected to cyclic loading. The computer program CFTPILE was developed as a part of this study. The pile is modeled as a beam element on a non-linear soil medium, which is able to resist compression only. Information on the soil-pile interaction and the stress-strain relationships for concrete and steel is required in order to calculate the response of the pile. The soil-pile interaction is assumed to follow a P-y curve proposed by Yan and Byrne. The formation of gaps between pile and soil is taken into account in the analysis. Tomii and Sakino's confined concrete model is adopted to determine the stress-strain relationship for the concrete inside steel tube. Steel is assumed to be elasto-perfectly plastic. Numerical examples are presented for a CFT and a Hollow section pile. Variability of pile capacity caused by the uncertainty in soil properties is investigated using the computer program RELAN and a response surface involving six random variables. The cumulative distribution function for maximum pile capacity is calculated for cases with and without correlation between the soil variables.
Hawking Radiation Correlations of Evaporating Black Holes in JT Gravity
Creators: name: Hollowood, Timothy J.
name: Kumar, S. Prem
name: Legramandi, Andrea
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We consider the Hawking radiation emitted by an evaporating black hole in JT gravity and compute the entropy of arbitrary subsets of the radiation in the slow evaporation limit, and find a zoo of possible island saddles. The Hawking radiation is shown to have long range correlations. We compute the mutual information between early and late modes and bound from below their squashed entanglement. A small subset of late modes are shown to be correlated with modes in a suitably large subset of the radiation previously emitted as well as later modes. We show how there is a breakdown of the semi-classical approximation in the form of a violation of the Araki-Lieb triangle entropy inequality, if the interior of the black hole and the radiation are considered to be separate systems. Finally, we consider how much of the radiation must be collected, and how early, to recover information thrown into the black hole as it evaporates.
description: 37 pages
Household Welfare Cost of the Indonesian Macroeconomic Crisis
Creators: name: Fabiosa, Jacinto F.
name: Jensen, Helen H.
name: Yan, Dong
name: Fabiosa, Jacinto F.
name: Jensen, Helen H.
name: Yan, Dong
Publisher: name: Unknown
Year: 2005
Subjects: Consumer/Household Economics

description: A theoretically consistent incomplete demand system is estimated to quantify the cost of the 1997 microeconomic crisis. Welfare cost per person was $128, which translates to $26.12 billion total cost. This amount is equivalent to agriculture's GDP contribution, and sufficient to pay for Indonesia's total annual government budget.
Mineral dust increases the habitability of terrestrial planets but confounds biomarker detection
Creators: name: Boutle, Ian A.
name: Joshi, Manoj
name: Lambert, F. Hugo
name: Mayne, Nathan J.
name: Lyster, Duncan
name: Manners, James
name: Ridgway, Robert
name: Kohary, Krisztian
Publisher: name: arXiv
Year: 2020
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Identification of habitable planets beyond our solar system is a key goal of current and future space missions. Yet habitability depends not only on the stellar irradiance, but equally on constituent parts of the planetary atmosphere. Here we show, for the first time, that radiatively active mineral dust will have a significant impact on the habitability of Earth-like exoplanets. On tidally-locked planets, dust cools the day-side and warms the night-side, significantly widening the habitable zone. Independent of orbital configuration, we suggest that airborne dust can postpone planetary water loss at the inner edge of the habitable zone, through a feedback involving decreasing ocean coverage and increased dust loading. The inclusion of dust significantly obscures key biomarker gases (e.g. ozone, methane) in simulated transmission spectra, implying an important influence on the interpretation of observations. We demonstrate that future observational and theoretical studies of terrestrial exoplanets must consider the effect of dust.
description: 15 pages, 4 figures, 3 tables
Effectively Open Real Functions
Creators: name: Ziegler, Martin
Publisher: name: arXiv
Year: 2005
Subjects: subject: Logic in Computer Science (cs.LO)
subject: FOS: Computer and information sciences
subject: F.4.1

description: A function f is continuous iff the PRE-image f^{-1}[V] of any open set V is open again. Dual to this topological property, f is called OPEN iff the IMAGE f[U] of any open set U is open again. Several classical Open Mapping Theorems in Analysis provide a variety of sufficient conditions for openness. By the Main Theorem of Recursive Analysis, computable real functions are necessarily continuous. In fact they admit a well-known characterization in terms of the mapping V+->f^{-1}[V] being EFFECTIVE: Given a list of open rational balls exhausting V, a Turing Machine can generate a corresponding list for f^{-1}[V]. Analogously, EFFECTIVE OPENNESS requires the mapping U+->f[U] on open real subsets to be effective. By effectivizing classical Open Mapping Theorems as well as from application of Tarski's Quantifier Elimination, the present work reveals several rich classes of functions to be effectively open.
description: added section on semi-algebraic functions; to appear in Proc. http://cca-net.de/cca2005
Heavy-Flavor Collectivity - Light-Flavor Thermalization at RHIC
Creators: name: Schweda, K.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: Flow measurements of multi-strange baryons from Au + Au collisions at RHIC energies demonstrate that collectivity develops before hadronization, among partons. To pin down the partonic EOS of matter produced at RHIC, the status of thermalization in such collisions has to be addressed. We propose to measure collective flow of heavy-flavor quarks, e.g. charm quarks, as an indicator of thermalization of light flavors ($u,d,s$). The completion of the time of flight barrel and the proposed upgrade with a $μ$Vertex detector for heavy-flavor identification in STAR are well suited for achieving these goals.
description: proceedings of the ISMD 2005 conference, Kromeriz, Czech Republic; 6 pages, 4 figures
The broad-band X-ray spectrum of the blazar PKS B1830-211 by Chandra and INTEGRAL
Creators: name: De Rosa, A.
name: Piro, L.
name: Tramacere, A.
name: Massaro, E.
name: Walter, R.
name: Bassani, L.
name: Malizia, A.
name: Bird, A. J.
name: Dean, A. J.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: In this paper we present a broad-band study of the X-ray emission of the blazar PKS1830-211 based on Chandra and Integral observations. Notwithstanding the high redshift (z=2.507), it is a bright X-ray source (F(2-10 keV)~10^{-11} erg cm^{-2} s^{-1}), due to gravitational lensing by an intervening galaxy at z=0.89. Previous X-ray observations attribute the observed absorption at E<2 keV to the lensing galaxy. Our analysis, although not in contrast with this hypothesis, suggests also the possibility of an intrinsic (ionized) absorption, taking place at the front side of the jet. This scenario is also supported by some evidence, in the same data, of a feature observed at 2.15 keV which can be interpreted as a blueshifted iron line (v/c ~ 0.18). The SED of PKS1830-211 can be well modelled by combining a Synchrotron Self-Compton component and an external source of photons to be scattered up to γ-ray energies by relativistic electrons moving outward in the jet. The main source of low energy photons is a dust torus at the temperature of 10^3 K as expected in MeV blazars.
description: Accepted for publication in A&A
Inductive and Electrostatic Acceleration in Relativistic Jet-Plasma Interactions
Creators: name: Ng, Johnny S. T.
name: Noble, Robert J.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report on the observation of rapid particle acceleration in numerical simulations of relativistic jet-plasma interactions and discuss the underlying mechanisms. The dynamics of a charge-neutral, narrow, electron-positron jet propagating through an unmagnetized electron-ion plasma was investigated using a three-dimensional, electromagnetic, particle-in-cell computer code. The interaction excited magnetic filamentation as well as electrostatic plasma instabilities. In some cases, the longitudinal electric fields generated inductively and electrostatically reached the cold plasma wave-breaking limit, and the longitudinal momentum of about half the positrons increased by 50% with a maximum gain exceeding a factor of 2 during the simulation period. Particle acceleration via these mechanisms occurred when the criteria for Weibel instability were satisfied.
description: Revised for Phys. Rev. Lett. Please see publised version for best graphics
Running-phase state in a Josephson washboard potential
Creators: name: Paraoanu, G. S.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We investigate the dynamics of the phase variable of an ideal underdamped Josephson junction in switching current experiments. These experiments have provided the first evidence for macroscopic quantum tunneling in large Josephson junctions and are currently used for state read-out of superconducting qubits. We calculate the shape of the resulting macroscopic wavepacket and find that the propagation of the wavepacket long enough after a switching event leads to an average voltage increasing linearly with time.
description: 6 pages, 3 figures
Integrated economy of humans and biological resources: A general equilibrium approach
Creators: name: Tajibaeva, Liaila
name: Tajibaeva, Liaila
Publisher: name: Unknown
Year: 2005
Subjects: Resource /Energy Economics and Policy

description: This paper develops a model of economic growth where a natural resource is an important part of the economy. In the environment of labor and capital markets and an open access resource stock the general equilibrium approach allows for the endogenous prices and consumption, as well as labor allocation between employment and harvest of the resource for own consumption. Equilibrium for the model is defined and characterized. The analysis of steady state and approach dynamics show that if an economy has a high capital stock and high employment then it can converge to a steady state without depleting an open access resource stock. However, if an economy has low capital stock and low employment then it can deplete its resource stock.
Further Results on Active Magnetic Bearing Control with Input Saturation
Creators: name: Mazenc, Frederic
name: de Queiroz, Marcio S.
name: Malisoff, Michael
name: Gao, Feng
Publisher: name: arXiv
Year: 2006
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics
subject: 93D15

description: We study the low-bias stabilization of active magnetic bearings (AMBs) subject to voltage saturation based on a recently proposed model for the AMB switching mode of operation. Using a forwarding-like approach, we construct a stabilizing controller of arbitrarily small amplitude and a control-Lyapunov function for the AMB dynamics. We illustrate our construction using a numerical example.
description: 9 pages, 2 figures. IEEE Transactions on Control Systems Technology, accepted for publication in January 2006
Comparative Evaluation of the Performance of Spans of Control Designs in Grain Supply Chains
Creators: name: Baiyee-Mbi, Agbor-Baiyee
name: Mazzocco, Michael A.
name: Baiyee-Mbi, Agbor-Baiyee
name: Mazzocco, Michael A.
Publisher: name: Unknown
Year: 2005
Subjects: Crop Production/Industries

description: A fuzzy multi-objective linear programming model is used to analyze the performances of three spans of control designs that are observed in the U.S grain industry. Performance of the grain supply chain increases with amount of control and compromise.
A genetic-algorithm based automatic model calibrator for the UBC watershed model
Creators: name: Lan, Yao-Hung
Publisher: name: University of British Columbia
Year: 2009

description: In this study, an optimization and search technique, based on the genetic algorithms (GAs) approach, is successfully used to develop an automatic model calibrator for the UBC Watershed Model. Unlike the existing random search calibration procedure, which limits the number of simultaneously calibrated modeling parameters to groups of about three to six at a time, the new GA-based calibrator allows all modeling parameters to be simultaneously evaluated. Because of the non-linear interactions between the modeling parameters, the simultaneous evaluation of all modeling parameters is demonstrated to achieve a good model calibration efficiently and quickly. The fundamental components of GAs as inspired by the Darwinian principle of natural selection are explained in detail in order to develop a complete GA-based model calibrator. A flow chart is used to illustrate the computational implementation of the GA procedures. Why GAs can work efficiently in finding an optimal set of modeling parameter values is explained by the schema theory with mathematical proofs provided. To test the soundness of the GA code developed for the automatic calibrator of the UBC Watershed Model, two well-studied watersheds in the Province of British Columbia, Campbell River and Illecillewaet River, are used. The effects of genetic operators (crossover, niching and elitism) on GA search efficiency are individually demonstrated. To objectively determine the performance of a calibrated watershed model, the difference between the observed and simulated streamflows is statistically measured. Four statistical measures are evaluated: coefficient of linear correlation (or coefficient of determination), Nash & Sutcliffe coefficient of efficiency (e!), least squares objective function and least absolute difference objective function are introduced. GA computational experiments show that the Nash & Sutcliffe coefficient of efficiency (e!) exhibits the most consistently decreasing trend of streamflow volume error (dV/V) as the coefficient value increases. A fifth statistical measure, the modified Nash & Sutcliffe coefficient (eopt!), is also used to quantify the difference between the observed and simulated streamflow data, and ensures the optimal or near-optimal set of model parameter values found at the end of a GA search achieves both high el and low dV/V at the same time.
Magnetic resonance of collective paramagnets with gapped excitations spectrum
Creators: name: Glazkov, V. N.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Some magnets due to particular geometry of the exchange bonds do not undergo transition to the conventional magnetically ordered state despite of the presence of significant exchange couplings. Instead, a collective paramagnetic state is formed. The later state can remain stable down to $T=0$ if the ground state of this magnet turns out to be nonmagnetic singlet separated from the excited triplet states by an energy gap. Low-temperature spin dynamics of the collective paramagnets with gapped excitations spectrum (or spin-gap magnets) can be described in terms of a dilute gas of the triplet excitations. Applied magnetic field can suppress the energy gap, resulting in the formation of the gapless spin-liquid state or even leading to the unusual phenomenon of field-induced antiferromagnetic order. Introduction of defects in the crystallographic structure of the spin-gap magnet can result either in the formation of multi-spin paramagnetic center or in the formation of randomly distributed modified exchange bonds in the crystal. This review includes results of electron spin resonance (ESR) spectroscopy study of several representative quantum paramagnets with gapped excitations spectrum: quasy-two-dimensional magnet \phcc{}, quasy-one-dimensional magnets of "spin-tube" type \sul{} and "spin-ladder" type \dimpy{}. We will demonstrate that ESR absorption spectra reveal common features of these systems: ESR spectroscopy allows to observe and characterize fine structure if the triplet energy levels, to identify many-particles relaxation processes in the gas of triplet excitations and to observe collective spin-wave oscillations in the field induced antiferromagnetically ordered state, as well as to observe some individual features of the studied systems.
description: This text is an expanded author-translated version of the review prepared for the memorial issue of Journal of Experimental and Theoretical Physics dedicated to 100-year anniversary of A.S.~Borovik-Romanov (full memorial volume is available as JETP 131 No.1 (2020) [ZhETF 158 No.1 (2020)])
Partonic structure of the Nucleon in QCD and Nuclear Physics: new developments from old ideas
Creators: name: Radici, Marco
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The nucleon is an ideal laboratory to solve QCD in the nonperturbative regime. There are several experimental observations that still lack a rigorous interpretation; they involve the nucleon as a (polarized) target as well as a beam (in collisions and Drell-Yan processes). These data look like big azimuthal and spin asymmetries, related to the transverse polarization and momentum of the nucleon and/or the final detected particles. They suggest internal reaction mechanisms that are suppressed in collinear perturbative QCD but that are "natural" in Nuclear Physics: quark helicity flips, residual final state interactions, etc.. In my talk, I will give a brief survey of the main results and I will flash the most recent developments and measurements.
description: to appear in the proceedings of the X Convegno su problemi di Fisica Nucleare e Teorica, Cortona (Italy), 6-9 Oct. 2004; ws-proc9x6.cls included
NLTE spectral analysis of the intermediate helium-rich subdwarf B star CPD-20°1123
Creators: name: Löbling, L.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Subdwarf B (sdB) stars are core helium-burning stars with stratified atmospheres. Their atmospheres are dominated by hydrogen (H) while the helium (He) and metal abundances are shaped by an interplay of gravitational settling and radiative levitation. However, a small fraction of these show spectra dominated by He I absorption lines. In between these groups of He-deficient and extreme He-rich sdBs, some are found to have intermediate surface He abundances. These objects are proposed to be young "normal" (He-deficient) sdBs for which the dynamical stratification of the atmosphere is still ongoing. We present an analysis of the optical spectrum of such an intermediate He-rich sdB, namely CPD-20°1123, by means of non-local thermodynamic equilibrium (NLTE) stellar atmosphere models. It has a He-to-H number ratio of $\mathrm{He/H} = 0.13 \pm 0.05$ and its effective temperature of $T_\mathrm{eff} = 25\,500 \pm 1\,000$ together with a surface gravity of $\log\,(g\,/\,\mathrm{cm}/\mathrm{s}^2) = 5.3 \pm 0.3$ places the star close to the high-temperature edge until which it may be justified to use LTE model atmospheres. This work states a test of the Tübingen NLTE Model Atmosphere Package for this temperature regime. We present the first application of revised, elaborated model atoms of low ionization stages of light metals usable with this atmosphere code.
description: 16 pages, 13 figures
Discovery of a quantum limit Chern magnet TbMn6Sn6
Creators: name: Yin, Jia-Xin
name: Ma, Wenlong
name: Cochran, Tyler A.
name: Xu, Xitong
name: Zhang, Songtian S.
name: Tien, Hung-Ju
name: Shumiya, Nana
name: Cheng, Guangming
name: Jiang, Kun
name: Lian, Biao
name: Song, Zhida
name: Chang, Guoqing
name: Belopolski, Ilya
name: Multer, Daniel
name: Litskevich, Maksim
name: Cheng, Zijia
name: Yang, Xian
name: Swidler, Bianca
name: Zhou, Huibin
name: Lin, Hsin
name: Neupert, Titus
name: Wang, Ziqiang
name: Yao, Nan
name: Chang, Tay-Rong
name: Jia, Shuang
name: Hasan, M. Zahid
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The quantum level interplay between geometry, topology, and correlation is at the forefront of fundamental physics. Owing to the unusual lattice geometry and breaking of time-reversal symmetry, kagome magnets are predicted to support intrinsic Chern quantum phases. However, quantum materials hosting ideal spin-orbit coupled kagome lattices with strong out-of-plane magnetization have been lacking. Here we use scanning tunneling microscopy to discover a new topological kagome magnet TbMn6Sn6, which is close to satisfying the above criteria. We visualize its effectively defect-free purely Mn-based ferromagnetic kagome lattice with atomic resolution. Remarkably, its electronic state exhibits distinct Landau quantization upon the application of a magnetic field, and the quantized Landau fan structure features spin-polarized Dirac dispersion with a large Chern gap. We further demonstrate the bulk-boundary correspondence between the Chern gap and topological edge state, as well as the Berry curvature field correspondence of Chern gapped Dirac fermions. Our results point to the realization of a quantum-limit Chern phase in TbMn6Sn6, opening up an avenue for discovering topological quantum phenomena in the RMn6Sn6 (R = rare earth element) family with a variety of magnetic structures. Our visualization of the magnetic bulk-boundary-Berry correspondence covering real and momentum space demonstrates a proof-of-principle method revealing topological magnets.
description: To appear in Nature (2020)
Seeing the forest and the trees: a spatial analysis of common property land use
Creators: name: Alix-Garcia, Jennifer Marie
name: Alix-Garcia, Jennifer Marie
Publisher: name: Unknown
Year: 2004
Subjects: Farm Management

description: The paper presents a theory of the deforestation of common property forest over space and tests this theory using data from 319 Mexican ejidos. One of the main implications of the model is that at a parcel level, the deforestation decision depends on the qualities of that parcel relative to the others within the community and on aggregate, the decision of how much forest to convert to pasture or agricultural land depends upon the entire distribution of land quality and distance in the ejido. The theory also relates the physical characteristics of the converted land to its marginal value. Aggregate community characteristics affect the demand for forest conversion, in particular, inequality can operate both through individual incentives as well as by increasing cooperation. Empirically, we see that within a given ejido, parcels of forest that are relatively closer, of lower slope and altitude are at higher risk of deforestation, and that communities with large tracts of low-sloped, accessible land have considerably higher overall forest loss. This suggests that payments in exchange for standing forest should be higher for land within an ejido with these types of characteristics and between ejido targeting should focus on those with large tracts of accessible forests on land of good quality for agriculture or pasture. We also find that expanding the agricultural/pastoral frontier into increasingly remote and highly sloped land has negative effects on the value of this land. At a community level, we find that demand is increasing with the number of ejido members, but that this effect can be mitigated by higher inequality. The inequality effect operates both through individual incentives and by influencing overall cooperation: users at the lower end of the land distribution use the commons less intensively than those at the high end, and communities with high inequality have lower participation rates but a higher likelihood of implementing rules for commons management. This suggests that the formation of groups responsible for commons management, with members composed of those with the highest stake in the resource, can lead to more effective resource exploitation.
CROWDING OUT OPEN SPACE: THE EFFECTS OF FEDERAL LAND PROGRAMS ON LAND TRUST ACTIVITY
Creators: name: Parker, Dominic P.
name: Thurman, Walter N.
name: Parker, Dominic P.
name: Thurman, Walter N.
Publisher: name: Unknown
Year: 2004
Subjects: Land Economics/Use

description: Federal land programs, such as the Conservation Reserve, provide land amenities with public goods attributes. Private land trusts supply related amenities through their holdings of land and conservation easements. We analyze, in a unique county-level panel, the effects of the federal programs on private land trust land preservation.
Density-matrix renormalization group study of pairing when electron-electron and electron-phonon interactions coexist: effect of the electronic band structure
Creators: name: Tezuka, Masaki
name: Arita, Ryotaro
name: Aoki, Hideo
Publisher: name: arXiv
Year: 2005
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Density-matrix renormalization group is used to study the pairing when both of electron-electron and electron-phonon interactions are strong in the Holstein-Hubbard model at half-filling in a region intermediate between the adiabatic (Migdal's) and antiadiabatic limits. We have found: (i) the pairing correlation obtained for a one-dimensional system is nearly degenerate with the CDW correlation in a region where the phonon-induced attraction is comparable with the electron-electron repulsion, but (ii) pairing becomes dominant when we destroy the electron-hole symmetry in a trestle lattice. This provides an instance in which pairing can arise, in a lattice-structure dependent manner, from coexisting electron-electron and electron-phonon interactions.
description: 4 pages, 3 figures; to appear in Phys. Rev. Lett
Domain wall propagation by spin-orbit torques in in-plane magnetized systems
Creators: name: Kohno, Ryuhei
name: Sampaio, João
name: Rohart, Stanislas
name: Thiaville, André
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The effect of damping-like spin-orbit torque (DL SOT) on magnetic domain walls (DWs) in in-plane magnetised soft tracks is studied analytically and with micromagnetic simulations. We find that DL SOT drives vortex DWs, whereas transverse DWs, the other typical DW structure in soft tracks, propagate only if the Dzyaloshinskii-Moriya interaction (DMI) is present. The SOT drive can add to, and be more efficient than, spin-transfer torque (STT), and so may greatly benefit applications that require in-plane DWs. Our analysis based on the Thiele equation shows that the driving force arises from a cycloidal distortion of the DW structure caused by geometrical confinement or DMI. This distortion is higher, and the SOT more efficient, in narrower, thinner tracks. These results show that the effects of SOT cannot be understood by simply considering the effective field at the center of the structure, an ill-founded but often-used estimation. We also show that the relative magnitude of STT and DL SOT can be determined by comparing the motion of different vortex DW structures in the same track.
description: Accepted for publication in Physical Review B Rapid Communications
Chiral resolution by composite Raman pulses
Creators: name: Torosov, Boyan T.
name: Drewsen, Michael
name: Vitanov, Nikolay V.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We present two methods for efficient detection of chiral molecules based on sequences of single pulses and Raman pulse pairs. The chiral molecules are modelled by a closed-loop three-state system with different signs in one of the couplings for the two enantiomers. One method uses a sequence of three interaction steps: a single pulse, a Raman pulse, and another single pulse. The other method uses a sequence of only two interaction steps: a Raman pulse, and a single pulse. The second method is simpler and faster but requires a more sophisticated Raman pulse than the first one. Both techniques allow for straightforward generalizations by replacing the single and Raman pulses with composite pulse sequences. The latter achieve very high signal contrast and far greater robustness to experimental errors than by using single pulses. We demonstrate that both constant-rotation (i.e., with phase compensation) and variable-rotation (i.e., with phase distortion) composite pulses can be used, the former being more accurate and the latter being simpler and faster.
description: 7 pages, 7 figures
NATIONAL DIFFERENCES IN THE UPTAKE OF AGRI-ENVIRONMENTAL SCHEMES: AN EXPLANATION
Creators: name: Salhofer, Klaus
name: Glebe, Thilo W.
name: Salhofer, Klaus
name: Glebe, Thilo W.
Publisher: name: Unknown
Year: 2004
Subjects: Environmental Economics and Policy

description: The number of agri-environmental programs, as well as the share of agricultural land covered under these programs, varies significantly between EU member states. We analyze national differences in the uptake of agri-environmental programs by developing a model of countries' political objective function. Based on this model we identify six factors which may explain the extent to which agri-environmental policies are implemented: environmental benefits, opportunity costs of participation, financial budget pressure, the share of program expenditures financed by the EU, contribution to the EU budget, and political weight attributed to farmers' income. The conceptual approach is then supplemented by an empirical analysis.
Erythrocyte-erythrocyte aggregation dynamics under shear flow
Creators: name: Abbasi, Mehdi
name: Farutin, Alexander
name: Ez-Zahraouy, Hamid
name: Benyoussef, Abdelilah
name: Misbah, Chaouqi
Publisher: name: arXiv
Year: 2020
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Computational Physics (physics.comp-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Red blood cells (RBCs) -- erythrocytes -- suspended in plasma tend to aggregate and form rouleaux. During aggregation the first stage consists in the formation of RBC doublets [Blood cells, molecules, and diseases 25, 339 (1999)]. While aggregates are normally dissociated by moderate flow stresses, under some pathological conditions the aggregation becomes irreversible, which leads to high blood viscosity and vessel occlusion. We perform here two-dimensional simulations to study the doublet dynamics under shear flow in different conditions and its impact on rheology. We sum up our results on the dynamics of doublet in a rich phase diagram in the parameter space (flow strength, adhesion energy) showing four different types of doublet configurations and dynamics. We find that membrane tank-treading plays an important role in doublet disaggregation, in agreement with experiments on RBCs. A remarkable feature found here is that when a single cell performs tumbling (by increasing vesicle internal viscosity) the doublet formed due to adhesion (even very weak) remains stable even under a very strong shear rate. It is seen in this regime that an increase of shear rate induces an adaptation of the doublet conformation allowing the aggregate to resist cell-cell detachment. We show that the normalized effective viscosity of doublet suspension increases significantly with the adhesion energy, a fact which should affect blood perfusion in microcirculation.
description: 14pages
Detailed description of the bumblebee risk assessment framework and its validation
Creators: name: Butler Et Al. (2009)
Publisher: name: Zenodo
Year: 2019
Subjects: Bumblebee equations

description: This document is from Butler et al. (2009). It contains equations for risk score calculation of bumblebees. (Reference: BUTLER, S. J., BROOKS, D., FEBER, R. E., STORKEY, J., VICKERY, J. A. & NORRIS, K. 2009. A cross-taxonomic index for quantifying the health of farmland biodiversity. Journal of Applied Ecology, 46, 1154-1162.)
On the ground state energy for a magnetic Shcrödinger operator and the effect of the De Gennes Boundary condition
Creators: name: Kachmar, Ayman
Publisher: name: arXiv
Year: 2006
Subjects: subject: Mathematical Physics (math-ph)
subject: Dynamical Systems (math.DS)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 81Q10; 35P15; 35Q55; 82D55

description: Motivated by the Ginzburg-Landau theory of superconductivity, we estimate in the semi-classical limit the ground state energy of a magnetic Schrödinger operator with De Gennes boundary condition and we study the localization of the ground state. We exhibit cases when the De Gennes boundary condition has strong effects on this localization.
description: content revised
Band Representations and Topological Quantum Chemistry
Creators: name: Cano, Jennifer
name: Bradlyn, Barry
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: In this article, we provide a pedagogical review of the theory of topological quantum chemistry and topological crystalline insulators. We begin with an overview of the properties of crystal symmetry groups in position and momentum space. Next, we introduce the concept of a band representation, which quantifies the symmetry of topologically trivial band structures. By combining band representations with symmetry constraints on the connectivity of bands in momentum space, we show how topologically nontrivial bands can be catalogued and classified. We present several examples of new topological phases discovered using this paradigm, and conclude with an outlook towards future developments.
description: 24pgs, 2 figures. To appear in Annual Reviews of Condensed Matter Physics
A COMPARISON OF RISK MANAGEMENT STRATEGIES FOR INDIANA GRAIN PRODUCERS
Creators: name: Rios, Ana R.
name: Patrick, George F.
name: Rios, Ana R.
name: Patrick, George F.
Publisher: name: Unknown
Year: 2004
Subjects: Risk and Uncertainty

description: Crop insurance and pre-harvest pricing strategies were analyzed for all years and "years following an normal crop year" from 1986 to 2001 in three counties. Although pre-harvest marketing strategies had the highest certainty equivaenls, net farm revenues were lower and crop insurances were more common strategies following normal crop years.
DOES PRIVATE LABEL OWNERSHIP AND PRICING STRUCTURE MATTER?
Creators: name: Pittman, Grant
name: Love, H. Alan
name: Pittman, Grant
name: Love, H. Alan
Publisher: name: Unknown
Year: 2004
Subjects: Demand and Price Analysis

description: This article provides an analysis of the two-stage game between manufacturers and retailers. Response functions showing how prices are set are derived for the case of a manufacturer producing one and multiple goods and for a retailer selling multiple goods. The functions are expressed in terms of elasticities, budget shares, and variable production costs. An application using ready-to-eat cereals is conducted to investigate the pricing structure and ownership of private label cereals.