cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
The value and Cost of Information
Creators: name: Nieuwoudt, W. L.
name: Nieuwoudt, W. L.
Publisher: name: Unknown
Year: 1981
Subjects: Production Economics

description: Mathematical models are derived measuring the social benefit and cost of information in comparison to the social benefit or cost of an input (fertilizer) subsidy under different factor market assumptions. In 1975, 54 countries subsidized fertilizers (FAO). In the following countries, the subsidy was as high as 50 percent of the average price of all fertilizers: Ghana, Libya, Niger, Tanzania, Uganda (certain farmers), Iran, and Sri Lanka. In Togo, the subsidy on urea in 1974 was 82 percent (FAO).
title: Daily Monetary Policy Rules and the ECB’s Medium-Term Orientation
title: MAGKS - Joint Discussion Paper Series in Economics
Creators: name: Klose, Jens
Publisher: name: Philipps-Universität Marburg
Year: 2021
Subjects: Monetary policy rules
Economics
Wirtschaft
ECB
medium-term orientation

description: This article develops the first granular database on daily real-time inflation rates and output. Four different European forecast sources and three computation methods are applied to calculate those daily data. These are used in two types of monetary policy rules, for three different interest rates as the dependent variable. The results indicate that the main source of differences in the forecast horizons and response coeffcients is not the data sources or the computation method but, rather, the monetary policy rule applied and the interest rate used. That is, the results differ if unconventional monetary policies are considered. Moreover, the results tend to be time-varying; that is, sudden shifts in the optimal forecast horizon can be identified, leading to substantially altered policy rules.
Modified Gravity with Torsion
Creators: name: Negreanu, Carina Suzana
Publisher: name: Apollo - University of Cambridge Repository
Year: 2019
Subjects: Gravity
Gauge Theory of Gravity
Cosmology

description: We are at a point in time when alternative gravitational theories are beginning to be constrained by high precision cosmological and astrophysical data. The work in this thesis focuses on applications of a particular modified gravity theory, the extended Weyl Gauge Theory (eWGT), that was recently developed by Prof. Lasenby and Prof. Hobson. The applications corresponds to subsets of the full theory that are applicable to different cosmological and astrophysical sectors. We start by investigating a simplified scenario that simulates a famous alternative theory of gravity, Weyl$^2$ Gravity. Recently a couple of issues have been raised regarding the validity of the theory. Starting from a gauge theory perspective we bring a fresh contribution to the debate. We argue against the classical formulation by showing that the theory cannot support astrophysical matter (introduced by a perfect fluid). Furthermore we extend the theory and show that even if we allow torsion to be present we cannot reach a physical setup. In this process we have discovered interesting properties of the torsion field that could play an important role in generalised cosmological setups. In the next application we consider a cosmology dictated by a Riemann$^2$ Lagrangian that can accommodate only radiation. We find new physical behaviour in the perturbed regime that discretises the power spectrum. We prove that the setup admits gravitational waves. Finally, we construct a new Lagrangian theory for spinning fluids. We show that it is compatible with current literature for a flat space time. Considering its extensibility we believe that it can be widely used in future research.
Dynamic Models for Stabilizing Food Prices
Creators: name: Halcrow, Harold G.
name: Takayama, Takashi
name: Halcrow, Harold G.
name: Takayama, Takashi
Publisher: name: Unknown
Year: 1981
Subjects: Financial Economics
Food Consumption/Nutrition/Food Safety

description: Multiyear dynamic spatial models of the U.S. grain, oilseed, and livestock (GOL) economy show how to stabilize prices in this part of the world food economy. The standard GOL model can be operated at modest cost, well within the limits of previous price support and storage programmes operated by the U.S. government. Appropriate application of the model and its derivatives will stabilize the U.S. GOL economy within a relatively narrow price band, and this will help to stabilize prices in other trading countries as well.
Magnetic hedgehog lattices in noncentrosymmetric metals
Creators: name: Okumura, Shun
name: Hayami, Satoru
name: Kato, Yasuyuki
name: Motome, Yukitoshi
Publisher: name: arXiv
Year: 2019
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The magnetic hedgehog lattice (HL) is a noncoplanar magnetic texture with a periodic array of magnetic monopoles and anti-monopoles. Despite phenomenological and numerical studies thus far, there remain open issues on the microscopic origin, especially with respect to the recent experimental findings of two different types of HLs even at zero magnetic field. Here, we study the stability of the HLs for an effective spin model with long-range interactions arising from itinerant nature of electrons. By variational calculations and simulated annealing, we find that the HLs are stabilized in the ground state at zero magnetic field by the synergetic effect of the anti-symmetric exchange interactions generated by the spin-orbit coupling and the multiple-spin interactions generated by the spin-charge coupling. We also clarify the phase diagram in the magnetic fields, which includes topological phase transitions with pair annihilation of the monopoles and anti-monopoles depending on the field directions.
description: 14 pages, 10 figures
On-Farm Reserach to Develop Technologies Appropriate to Farmers
Creators: name: Byerlee, Derek
name: Biggs, Stephen
name: Collinson, Michael
name: Harrington, Larry
name: Winkelmann, Donald
name: Byerlee, Derek
name: Biggs, Stephen
name: Collinson, Michael
name: Harrington, Larry
name: Winkelmann, Donald
Publisher: name: Unknown
Year: 1981
Subjects: Farm Management
Research and Development/Tech Change/Emerging Technologies

description: It is now widely accepted that technological change is a necessary although by no means sufficient condition for agricultural development. It is clear that despite the widespread diffusion of new wheat and rice varieties, many new technologies are not being widely used by farmers because they do not fit the particular circumstances of farmers for whom they are intended. This is despite the fact that considerable public expenditures are often made to provide the infrastructure such as credit and markets to enable the farmer to adopt these tee hnologies. This paper attempts to synthesize our experiences with national research programmes and with the International Wheat and Maize Improvement Center's (CIMMYT) wheat and maize programmes in deveolping research methodologies to ensure that agricultural technologies generated by scarce research resources are consistent with the circumstances of target farmers. It emphasizes collaboration of technical and social scientists in on-farm research--both in diagnosing farmers' problems and demands for technology and in developing and testing in farmers' fields those technologies which appear to meet these problems.
Predictable Scanpath for Gaze Points Using Classification Models
Creators: name: Isiaka, Fatima
name: Awwal Adamu, Muhammed
Publisher: name: figshare
Year: 2025
Subjects: classificationCode: 460399
subject: Computer vision and multimedia computation not elsewhere classified
classificationCode: 460806
subject: Human-computer interaction

description: As the field of eye-tracking research advances, understanding how visual attention is allocated in dynamic environments has become increasingly relevant. This article explores the classification of scanpaths for fixations based on pupil measures, particularly in response to dynamic visual content. By examining the relationship between pupil dynamics and eye movement patterns, the aim is to enhance our understanding of visual cognition and improve applications, the novel method here is based on attention and performance applying the Euclidean path for shortest distance (EPSD) and a Region Convolutional Network embedded Support vector machine (RCNN-RCNN-SVM) for a notable correlation between pupil sizes (Constriction and Dilation) to task performance in relation with scanpaths. The result shows that people who displayed larger pupil diameters during fixations on complex areas of a webpage often also demonstrated slower task completion times and shorter scanpath, suggesting deep contemplation or struggle to process information effectively. These methods applied on scanpaths for fixations through pupil measures provide a deeper understanding of how users interact with dynamic webpages with explicit animated content. These findings can significantly aid web developers and designers in creating more intuitive and engaging interfaces that accommodate the ways users naturally navigate digital content.
Pairwise entanglement in symmetric multi-qubit systems
Creators: name: Wang, Xiaoguang
name: Molmer, Klaus
Publisher: name: arXiv
Year: 2001
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The concurrence, a quantitative measure of the entanglement between a pair of particles, is determined for the case where the pair is extracted from a symmetric state of N two-level systems. Examples are given for both pure and mixed states of the N-particle system, and for a pair extracted from two ensembles with correlated collective spins.
description: 7 pages, 3 figures
Public Crop Insurance For Developing Countries: The Lessons From the Japanese Experiment
Creators: name: Ahsan, Syed M.
name: Ahsan, Syed M.
Publisher: name: Unknown
Year: 1981
Subjects: Crop Production/Industries
International Development

description: In view of the overwhelming impact of agricultural risks on peasant economies, many governments have traditionally adopted various measures, often in an ad hoc manner, to help farmers partially meet the losses due to natural hazards. These measures often take the form of reduction of land rent and taxes, cancellation or postponement of loan repayments, and direct subsidies. There are several disadvantages with this practice. An important one is that farmers cannot expect assistance as a right, but only as a privilege, and as a consequence cannot take these possibilities fully into consideration in determining their courses of action (for example, choice of farming techniques or use of agricultural credit). Certainly, in the case of Japan, tenancy disputes over the rent reduction on the part of landlords during the depression years brought the final pressure on the government leading to the introduction of public crop insurance in 1939 (Yamauchi, p. 14-15). The advantages of all-risk crop insurance over these ad hoc measures on various aspects of the farm economy (innovative cultivating methods, credit, and overall stability) have been discussed in the literature (Bardhan; and Wharton).
Hydromagnetic Oscillations and Instabilities in Astrophysical Discs
Creators: name: Dewberry, Janosz Walker
Publisher: name: Apollo - University of Cambridge Repository
Year: 2019
Subjects: Astrophysics
Magnetohydrodynamics
Accretion discs
Waves
Magnetic fields
Fluid dynamics
Black holes
Cataclysmic variables
Protoplanetary discs
AGN
Numerical analysis
Numerical astrophysics
Instabilities
X-ray astronomy
Hydrodynamics
Eccentric discs

description: Highly supersonic, magnetized and differentially rotating, accretion flows provide an environment for the propagation of waves and the growth of instabilities unlike those normally encountered on Earth. In this dissertation, I investigate the properties of oscillations and instabilities in accretion discs, developing theoretical and numerical models to explore the physical nature of variability encountered in a variety of astrophysical contexts. Through linear theory and semi-analytical calculations, I first consider the physical properties of magnetically altered inertial waves. ‘Trapped inertial waves’ provide an attractive explanation of the fast variability observed in the emission from low-mass black hole binary systems, but such oscillations can be affected by magnetic tension provided by large-scale poloidal magnetic fields threading the accretion disc. Through local and global analyses, I constrain the modification of trapped inertial waves by poloidal, toroidal and helical magnetic fields. I then investigate the excitation of oscillations in deformed discs with eccentric, non-circular streamlines. Many processes can lead to the growth of eccentricity in accretion discs, and turbulence deriving from the excitation of inertial waves by a local parametric instability provides one mechanism for curbing this growth. However, eccentric discs also provide an environment for the excitation of additional, inherently global oscillations, and I present a framework facilitating a semi-analytical investigation of these modes. I finally employ numerical simulations to explore the dynamics of accretion disc oscillations in the non-linear regime. I first follow the non-linear saturation of inertial waves driven by parametric resonance in non-relativistic discs, and confirm the growth of a second family of large-scale, low-frequency oscillations. Using a pseudo-Newtonian framework to approximate relativistic effects, I then demonstrate the excitation of trapped inertial waves through non-linear coupling with accretion disc deformations in a black hole accretion disc, providing preliminary evidence that trapped inertial waves can be excited even in the presence of MHD turbulence
description: PhD primarily funded by a Cambridge International Scholarship provided by the Cambridge Commonwealth European and International Trust. Additional funding provided by the Vassar College De Golier Trust, the Cambridge Philosophical Society, and Churchill College.
Star Clusters as Type Ia Supernova Factories
Creators: name: Shara, Michael M.
name: Hurley, Jarrod R.
Publisher: name: arXiv
Year: 2002
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We find a remarkably enhanced production rate in star clusters (relative to the field) of very short period, massive double-white-dwarf stars and of giant-white dwarf binaries. These results are based on N-body simulations performed with the new GRAPE-6 special purpose hardware and are important in identifying and characterizing the progenitors of type Ia supernovae. The high incidence of very close double-white-dwarf systems is the result of dynamical encounters between (mostly) primordial binaries and other cluster stars. Orbital hardening rapidly drives these degenerate binaries to periods under ~10 hours. Gravitational radiation emission and mergers producing supra-Chandrasekhar objects follow in less than a Hubble time. If most stars are born in clusters then estimates of the double white dwarf merger rates in galaxies (due to cluster dynamical interaction) must be increased more than tenfold. A majority of the Roche lobe overflow giant-white dwarf binaries are not primordial; they are produced in exchange reactions. Most cases resulted in a common-envelope and formation of a double-white-dwarf binary rather than Supersoft X-ray sources leading possibly to a type Ia supernova.
description: 29 pages, 6 figures (2 color), 3 tables, accepted for publication in the Astrophysical Journal
Measurement of Bose-Einstein Correlations in e+e- -> W+W- Events at LEP
Creators: name: L3 Collaboration
Publisher: name: arXiv
Year: 2002
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Bose-Einstein correlations in W-pair production at LEP are investigated in a data sample of 629 pb^-1 collected by the L3 detector at centre-of-mass energies of 189-209 GeV. Bose-Einstein correlations between pions within a W decay are observed and found to be in good agreement with those in light-quark Z decay. No evidence is found for Bose-Einstein correlations between hadrons coming from different W's in the same event.
Thermal representations in group field theory: squeezed vacua and quantum gravity condensates
Creators: name: Assanioussi, Mehdi
name: Kotecha, Isha
Publisher: name: arXiv
Year: 2019
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We apply the formalism of thermofield dynamics to group field theory quantum gravity and construct thermal representations associated with generalised equilibrium Gibbs states using Bogoliubov transformations. The newly constructed class of thermal vacua are entangled, two-mode squeezed, thermofield double states. The corresponding finite temperature representations are inequivalent to the standard zero temperature one based on a degenerate vacuum. An interesting class of states, coherent thermal states, are defined and understood as thermal quantum gravity condensates.
description: v2, 11 pages, minor revisions, published version; v1, 10 pages
Geometry of WZW Orientifolds
Creators: name: Huiszoon, L. R.
name: Schalm, K.
name: Schellekens, A. N.
Publisher: name: arXiv
Year: 2001
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We analyze unoriented Wess-Zumino-Witten models from a geometrical point of view. We show that the geometric interpretation of simple current crosscap states is as centre orientifold planes localized on conjugacy classes of the group manifold. We determine the locations and dimensions of these planes for arbitrary simply-connected groups and orbifolds thereof. The dimensions of the O-planes turn out to be given by the dimensions of symmetric coset manifolds based on regular embeddings. Furthermore, we give a geometrical interpretation of boundary conjugation in open unoriented WZW models; it yields D-branes together with their images under the orientifold projection. To find the agreement between O-planes and crosscap states, we find explicit answers for lattice extensions of Gaussian sums. These results allow us to express the modular P-matrix, which is directly related to the crosscap coefficient, in terms of characters of the horizontal subgroup of the affine Lie algebra. A corollary of this relation is that there exists a formal linear relation between the modular P- and the modular S-matrix.
description: 35 pages LaTeX, 2 tables; Proof added for symmetric space relation; minor improvements; references added
Agricultural Pricing Policies in Developed and Developing Countries: Their Effects on Efficiency, Distribution, and Rural Change
Creators: name: Bale, Malcolm D.
name: Lutz, Ernst
name: Bale, Malcolm D.
name: Lutz, Ernst
Publisher: name: Unknown
Year: 1981
Subjects: Agricultural and Food Policy
Community/Rural/Urban Development
International Development

description: Agriculture is the main source of food for the world, and food is the basic input in the daily sustenance of humans. Yet, in many parts of the world there is insufficient food, which in turn implies inadequate agricultural output. The reasons for inadequate agricultural production are many and varied, ranging from poor distribution and poor production techniques to political intervention at various levels in the global agricultural complex. The most important reason for deficie.nt agricultural output is difficult to ascertain, but Schultz (1977) left no doubt as to his ranking of the causes. He suggested that the level of agricultural production depends not so much on technical considerations, but in large measure "on what governments do to agriculture." Schultz has long been the most ardent and eloquent spokesman of this position. See, for example, Schultz, 1964, 1977, and 1978. Export taxes on agricultural products provide government revenue and keep domesitc prices low, product price supports in developed countries maintain farm incomes and provide surpluses which in turn find their way to developing country markets to further depress domestic farm prices, and agricultural inputs are frequently either taxed or subsidized. Yet, the magnitude of these effects on agricultural output, income distribution between producers and consumers, efficiency, and on rural-urban migration is often not fully appreciated. This paper discusses government intervention in agricultural price determination, drawing on welfare theory to quantify the economic impacts on the previously mentioned variables. In this study, we examine France, Federal Republic of Germany, United Kingdom, Japan, Yugoslavia, Argentina, Egypt, Pakistan, and Thailand. The general theme of the paper is that the agricultural policies pursued by developing countries produce effects which are diametrically opposite to those produced by the policies of many developed countries, and that the policies of both are costly in terms of global welfare. Peterson addresses the developing country side of this question in a somewhat different manner.
title: Whatever it Takes to Understand a Central Banker – Embedding their Words Using Neural Networks.
title: MAGKS - Joint Discussion Paper Series in Economics
Creators: name: Baumgärtner, Martin
name: Zahner, Johannes
Publisher: name: Philipps-Universität Marburg
Year: 2021
Subjects: Word Embedding
Natural Language Processing
Economics
Wirtschaft
Central Bank Com- munication
Neural Network
Transfer Learning

description: Dictionary approaches are at the forefront of current techniques
for quantifying central bank communication. This paper proposes embeddings - a language model trained using machine learning techniques - to locate words and documents in a multidimensional vector space. To accomplish this, we utilize a text corpus that is unparalleled in size and diversity in the central bank communication literature, as well as introduce a novel approach to text quantification from computational linguistics. This allows us to provide high-quality central bank-specific textual representations and demonstrate their applicability by developing an index that tracks deviations in the Fed's communication towards inflation targeting. Our findings indicate that these deviations in communication significantly impact monetary policy actions, substantially reducing the reaction towards inflation deviation in the US.
A Profit Function Approach to the Efficiency Aspects of Land Reform in Zimbabwe
Creators: name: Khatri, Y.
name: Jayne, T.S.
name: Thirtle, C.
name: Khatri, Y.
name: Jayne, T.S.
name: Thirtle, C.
Publisher: name: Unknown
Year: 1997
Subjects: Agribusiness
Agricultural Finance
Land Economics/Use

description: The purchase of commercial farm land in Zimbabwe for resettlement has been a factor in government policy since independence in 1980, but from l 980 to 1989 only 52 000 families were relocated. The Land Acquisition Bill of 1992 made compulsory purchase easier and at present the government has announced its intention to considerably increase the rate of resettlement. But Zimbabwe has a serious food security problem and the output effects of land redistribution are a matter of dispute. The World Bank estimate that 3 million hectares of commercial farmland are under-utilized is contested by the Commercial Farmer's Union. Fitting a normalized restricted profit function to the data for the commercial sector allows estimation of the shadow price of commercial farm land. We find that the model suggests that the World Bank is correct, in that the marginal value product of land is negative, meaning that there is under-utilization. However, negative values of capital assets are common when real interest rates are negative, so the result should be treated with some caution. Also, the problem of identifying the unutilized land is not trivial and redistributing intra-marginal land would have output effects.
Subdivision and manifold techniques for isogeometric design and analysis of surfaces
Creators: name: Zhang, Qiaoling
Publisher: name: Apollo - University of Cambridge Repository
Year: 2019
Subjects: isogeometric analysis
finite elements
subdivision surfaces
manifold-based surfaces
unstructured meshes
thin shell

description: Design of surfaces and analysis of partial differential equations defined on them are of great importance in engineering applications, e.g., structural engineering, automotive and aerospace. This thesis focuses on isogeometric design and analysis of surfaces, which aims to integrate engineering design and analysis by using the same representation for both. The unresolved challenge is to develop a desirable surface representation that simultaneously satisfies certain favourable properties on meshes of arbitrary topology around the extraordinary vertices (EVs), i.e., vertices not shared by four quadrilaterals or three triangles. These properties include high continuity (geometric or parametric), optimal convergence in finite element analysis as well as simplicity in terms of implementation. To overcome the challenge, we further develop subdivision and manifold surface modelling techniques, and explore a possible scheme to combine the distinct appealing properties of the two. The unique advantages of the developed techniques have been confirmed with numerical experiments. Subdivision surfaces generate smooth surfaces from coarse control meshes of arbitrary topology by recursive refinement. Around EVs the optimal refinement weights are application-dependent. We first review subdivision-based finite elements. We then proceed to derive the optimal subdivision weights that minimise finite element errors and can be easily incorporated into existing implementations of subdivision schemes to achieve the same accuracy with much coarser meshes in engineering computations. To this end, the eigenstructure of the subdivision matrix is extensively used and a novel local shape decomposition approach is proposed to choose the optimal weights for each EV independently. Manifold-based basis functions are derived by combining differential-geometric manifold techniques with conformal parametrisations and the partition of unity method. This thesis derives novel manifold-based basis functions with arbitrary prescribed smoothness using quasi-conformal maps, enabling us to model and analyse surfaces with sharp features, such as creases and corners. Their practical utility in finite element simulation of hinged or rigidly joined structures is demonstrated with Kirchhoff-Love thin shell examples. We also propose a particular manifold basis reproducing subdivision surfaces away from EVs, i.e., B-splines, providing a way to combine the appealing properties of subdivision (available in industrial software) for design and manifold basis (relatively new) for analysis.
description: Cambridge International Scholarship Scheme (CISS) by Cambridge Trust
Simultaneous X-ray spectroscopy of YY Gem with Chandra and XMM-Newton
Creators: name: Stelzer, B.
name: Burwitz, V.
name: Audard, M.
name: Guedel, M.
name: Ness, J. -U.
name: Grosso, N.
name: Neuhaeuser, R.
name: Schmitt, J. H. M. M.
name: Predehl, P.
name: Aschenbach, B.
Publisher: name: arXiv
Year: 2002
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report on a detailed study of the X-ray spectrum of the nearby eclipsing spectroscopic binary YY Gem. Observations were obtained simultaneously with both large X-ray observatories, XMM-Newton and Chandra. We compare the high-resolution spectra acquired with the Reflection Grating Spectrometer onboard XMM-Newton and with the Low Energy Transmission Grating Spectrometer onboard Chandra, and evidence in direct comparison the good performance of both instruments in terms of wavelength and flux calibration. The strongest lines in the X-ray spectrum of YY Gem are from oxygen. Oxygen line ratios indicate the presence of a low-temperature component (1-4 MK) with density n_e < 2 10^{10} cm^-3. The X-ray lightcurve reveals two flares and a dip corresponding to the secondary eclipse. An increase of the density during phases of high activity is suggested from time-resolved spectroscopy. Time-resolved global fitting of the European Photon Imaging Camera CCD spectrum traces the evolution of temperature and emission measure during the flares. These medium-resolution spectra show that temperatures > 10^7 K are relevant in the corona of YY Gem although not as dominant as the lower temperatures represented by the strongest lines in the high-resolution spectrum. Magnetic loops with length on the order of 10^9 cm, i.e., about 5 % of the radius of each star, are inferred from a comparison with a one-dimensional hydrodynamic model. This suggests that the flares did not erupt in the (presumably more extended) inter-binary magnetosphere but are related to one of the components of the binary.
description: 15 pages, accepted for publication in A&A
Variable-range hopping conductivity in the copper-oxygen chains of La_3Sr_3Ca_8Cu_24O_41
Creators: name: Vuletic, T.
name: Korin-Hamzic, B.
name: Tomic, S.
name: Gorshunov, B.
name: Haas, P.
name: Dressel, M.
name: Akimitsu, J.
name: Sasaki, T.
name: Nagata, T.
Publisher: name: arXiv
Year: 2002
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We show that the spin chain/ladder compound La_3Sr_3Ca_8Cu_24O_41 is an insulator with hopping transport along the chains. In the temperature range 35 - 280 K, DC conductivity sigma_{DC}(T) follows Mott's law of variable-range hopping conduction; the frequency dependence has the form sigma(ν, T) = σ_{DC}(T) + A(T)ν^{s}, where s \approx 1. The conduction mechanism changes from variable-range hopping to nearest-neighbor hopping around T_{c} =300 K. The chain array thus behaves like a one-dimensional disordered system. Disorder is due to random structural distortions of chains induced by irregular coordination of the La/Sr/Ca ions.
description: 4 pages, 3 figures, accepted for publication in PRB
TEACHING ENGLISH AS A FOREIGN LANGUAGE: DIFFICULTIES AND CHALLENGES
Creators: name: Gafforova, Dilnura
Publisher: name: Zenodo
Year: 2025

description: This article discusses main problems faced in teaching English as foreign a language (TEFL), including pronunciation errors, grammatical difficulties, lack of practice and exposure to English in daily life. It also highlights how native language affects learners` pronunciation and their overall learning process. Additionally, the study provides some effective solutions for these issues, for instance, conducting specialized pronunciation classes with native speakers, doing exercises related to grammar, as much as possible, integrating English into everyday activities to be more fluent and articulate.
Macro-Economic Policy, Export Competitiveness and Poverty in Kenya: A General Equilibrium Analysis
Creators: name: Tyler, Godfrey J.
name: Tyler, Godfrey J.
Publisher: name: Unknown
Year: 1997
Subjects: subject: International Relations/Trade
subject: Marketing
subject: FOS: Economics and business
subject: Production Economics
subject: Public Economics

description: A Computable General Equilibrium model based on a Social Accounting Matrix for Kenya is used to simulate the effects of a 10 percent devaluation combined with a more progressive tax regime and elimination of indirect industrial taxes. For each policy simulation two specifications for the labour markets are adopted, the first assuming abundant supplies of labour at given nominal wages and the second assuming fixed supplies so that wages are determined endogenously. These crucially affect the results. The poor are better off under both scenarios; but only under the first (preferred) assumption does the policy also result in a large boost to GDP, to exports, particularly agricultural exports and to a dramatic improvement in the balance of payments, while maintaining real investment and essential government expenditure.
Detection and correction of errors with quantum tomography
Creators: name: Sazonova, Z. S.
name: Singh, Ranjit
Publisher: name: arXiv
Year: 2001
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: It is shown that quantum tomography can detect and correct unlimited number of errors during the evaluation of quantum algorithms on quantum computer.
Improving the dynamics of quantum sensors with reinforcement learning
Creators: name: Schuff, Jonas
name: Fiderer, Lukas J.
name: Braun, Daniel
Publisher: name: arXiv
Year: 2019
Subjects: subject: Quantum Physics (quant-ph)
subject: Machine Learning (cs.LG)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Recently proposed quantum-chaotic sensors achieve quantum enhancements in measurement precision by applying nonlinear control pulses to the dynamics of the quantum sensor while using classical initial states that are easy to prepare. Here, we use the cross-entropy method of reinforcement learning to optimize the strength and position of control pulses. Compared to the quantum-chaotic sensors with periodic control pulses in the presence of superradiant damping, we find that decoherence can be fought even better and measurement precision can be enhanced further by optimizing the control. In some examples, we find enhancements in sensitivity by more than an order of magnitude. By visualizing the evolution of the quantum state, the mechanism exploited by the reinforcement learning method is identified as a kind of spin-squeezing strategy that is adapted to the superradiant damping.
Floquet Amable, Histoire du parlement de Normandie, Rouen, É. Frère, 1842, tome 6.
Creators: name: Floquet, Amable
Publisher: name: NAKALA - https://nakala.fr (Huma-Num - CNRS)
publisherIdentifier: https://ror.org/04ces3204
publisherIdentifierScheme: ROR
Year: 2019

description: Source: https://gallica.bnf.fr/ark:/12148/bpt6k945663?rk=42918;4
description: Relation: vignette : https://www.nakala.fr/data/11280/531e7408
title: Leading Standards and the Business Cycle: Evidence from Loan Survey Releases
title: MAGKS - Joint Discussion Paper Series in Economics
Creators: name: Hafemann, Lucas
name: Tillmann, Peter
Publisher: name: Philipps-Universität Marburg
Year: 2021
Subjects: loan survey
Economics
Wirtschaft
risk-taking
shock identification
credit supply
instrumental variable lo- cal projections

description: The Fed's Senior Loan Officer Opinion Survey (SLOOS) is widely considered a good indicator of banks' lending conditions. We use the change in corporate bond spreads on SLOOS release days to instrument changes in lending standards. A series of estimated IV local projections shows that lending standards have highly significant effects on macroeconomic and financial variables. A relaxation of standards expands economic activity and eases _- financial conditions. We then use the change in spreads and the change in the VIX index on release days to identify a pure credit supply shock and a risk-taking shock using sign restrictions in a Bayesian VAR model. We find that an easing in lending has different consequences for both types of shocks. While the VIX, the excess bond premium and stock prices decrease after a pure credit supply shock, they increase after a risk-taking shock.
Validation of object detection in UAV-based images using synthetic data
Creators: name: Lee, Eung-Joo
name: Conover, Damon M.
name: Bhattacharyyaa, Shuvra S.
name: Kwon, Heesung
name: Hill, Jason
name: Evensen, Kenneth
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Object detection is increasingly used onboard Unmanned Aerial Vehicles (UAV) for various applications; however, the machine learning (ML) models for UAV-based detection are often validated using data curated for tasks unrelated to the UAV application. This is a concern because training neural networks on large-scale benchmarks have shown excellent capability in generic object detection tasks, yet conventional training approaches can lead to large inference errors for UAV-based images. Such errors arise due to differences in imaging conditions between images from UAVs and images in training. To overcome this problem, we characterize boundary conditions of ML models, beyond which the models exhibit rapid degradation in detection accuracy. Our work is focused on understanding the impact of different UAV-based imaging conditions on detection performance by using synthetic data generated using a game engine. Properties of the game engine are exploited to populate the synthetic datasets with realistic and annotated images. Specifically, it enables the fine control of various parameters, such as camera position, view angle, illumination conditions, and object pose. Using the synthetic datasets, we analyze detection accuracy in different imaging conditions as a function of the above parameters. We use three well-known neural network models with different model complexity in our work. In our experiment, we observe and quantify the following: 1) how detection accuracy drops as the camera moves toward the nadir-view region; 2) how detection accuracy varies depending on different object poses, and 3) the degree to which the robustness of the models changes as illumination conditions vary.
title: The Nexus between Lockdown Shocks and Economic Uncertainty: Empirical Evidence from a VAR Model
title: MAGKS - Joint Discussion Paper Series in Economics
Creators: name: Hafemann, Lucas
Publisher: name: Philipps-Universität Marburg
Year: 2021
Subjects: shock identi�cation
lockdown
COVID-19
market uncertainty
Economics
Wirtschaft

description: The contribution of this paper is twofold. First, we introduce a daily vector
autoregression (VAR) model for the US economy that allows discerning between lockdown shocks and a real business cycle shocks. With this methodology at hand, we then evaluate the impact of lockdown measures on economic uncertainty in a second step. Overall, we only find a moderate positive impact on uncertainty levels that is, in particular, weaker than the impact of the real business cycle shock. Taking a more granular perspective, we observe that in particular uncertainty related to entitlement programs increases and monetary policy uncertainty decreases after a lockdown shock.
Understanding travel mode choice: A new approach for city scale simulation
Creators: name: Hillel, Tim
Publisher: name: Apollo - University of Cambridge Repository
Year: 2019
Subjects: transport modelling
machine learning
discrete choice
mode choice
data fusion
urban planning
ensemble learning
demand modelling
random utility
travel demand
behavioural modelling
passenger movements
choice prediction
assisted specification

description: Understanding travel mode choice behaviour is key to effective management of transport networks, many of which are under increasing strain from rising travel demand. Conventional approaches to simulating mode choice typically make use of behavioural models either derived from stated preference choice experiments or calibrated to observed average mode shares. Whilst these models have played and continue to play a key role in economic, social, and environmental assessments of transport investments, there is growing need to gain a deeper understanding of how people interact with transport services, through exploiting available but fragmented data on passenger movements and transport networks. This thesis contributes to this need through developing a novel approach for urban mode choice prediction and applying it to historical trip records in the Greater London area. The new approach consists of two parts: (i) a data generation framework which combines multiple data-sources to build trip datasets containing the likely mode-alternative options faced by a passenger at the time of travel, and (ii) a modelling framework which makes use of these datasets to fit, optimise, validate, and select mode choice classifiers. This approach is used to compare the relative predictive performance of a complete suite of Machine Learning (ML) classification algorithms, as well as traditional utility-based choice models. Furthermore, a new assisted specification approach, where a fitted ML classifier is used to inform the utility function structure in a utility-based choice model, is then explored. The results identify three key findings. Firstly, the Gradient Boosting Decision Trees (GBDT) model is the highest performing classifier for this task. Secondly, the relative differences in predictive performance between classifiers are far smaller than has been suggested by previous research. In particular, there is a much smaller performance gap identified between Random Utility Models (RUMs) and ML classifiers. Finally, the assisted specification approach is successful in using the structure of a fitted ML classifier to improve the performance of a RUM. The resulting model achieves significantly better performance than all but the GBDT ML classifier, whilst maintaining a robust, interpretable behavioural model.
description: Funding provided by UK Engineering and Physical Sciences Research Council via the Future Infrastructure and Built Environment Centre for Doctoral Training (EP/L016095/1).
Aggregate Estimate of Environmental Degradation for Zimbabwe: Does Sustainable National Income Ensure Sustainability?
Creators: name: Adger, W. Neil
name: Grohs, Florian
name: Adger, W. Neil
name: Grohs, Florian
Publisher: name: Unknown
Year: 1997
Subjects: Environmental Economics and Policy
International Development

description: Standard measures of economic growth do not adequately reflect changes in aggregate welfare over time. Sustainable national income is therefore defined as Net National Product with adjustments for the degradation of renewable and non-renewable capital. Productivity loss rather than replacement cost is the most theoretically correct way to value resource depletion. Modified net product is estimated for the agriculture and forestry sectors of Zimbabwe by valuing the loss of forest stock and soil erosion. The results show that traditional measures overstate the value of the agricultural sector's product by approximately IO percent in 1989. It is argued that indicators of sustainable national income do not ensure sustainable development; as with all macroeconomic indicators, they do not account for distributional and equity issues which are at the crux of sustainable development, nor do they point to mechanisms which would ensure sustainable resource management. Indicators are therefore a necessary but not sufficient condition for the achievement of sustainable development.
title: Machine Learning in Energy Forecasts with an Application to High Frequency Electricity Consumption Data
title: MAGKS - Joint Discussion Paper Series in Economics
Creators: name: Heilmann, Erik
name: Henze, Janosch
name: Wetzel, Heike
Publisher: name: Philipps-Universität Marburg
Year: 2021
Subjects: machine learning
electricity consumption forecast
time series forecast
Economics
Wirtschaft
arti�cial neural network

description: Forecasting plays an essential role in energy economics. With new challenges and use cases in the energy system, forecasts have to meet more complex requirements, such as increasing temporal and spatial resolution of data. The concept of machine learning can meet these requirements by providing different model approaches and a standardized process of model selection. This paper provides a concise and comprehensible introduction to the topic by discussing the concept of machine learning in the context of energy economics and presenting an exemplary application to electricity load data. For this, we introduce and demonstrate the structured machine learning process containing the preparation, model selection and test of forecast models. This process is intended to serve as a general guideline for energy economists and practitioners who need to apply sophisticated forecast models.
An Overview of SLAC Experiment E158
Creators: name: Arroyo, Klejda Bega Carlos Gerardo
Publisher: name: arXiv
Year: 2002
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Overview of SLAC Experiment E158 May-June 2002 run
description: 3 pages, poster presented to the 2002 Physics in Collision Conference
The balance of knowledge flows
Creators: name: Abramo, Giovanni
name: D'Angelo, Ciriaco Andrea
name: Carloni, Massimiliano
Publisher: name: arXiv
Year: 2019
Subjects: subject: Digital Libraries (cs.DL)
subject: FOS: Computer and information sciences

description: In analogy to the technology balance of payments, in this paper we propose a possible way to set up a "balance of knowledge flows" (BKF), recording world flows of knowledge within the scientific community. Adopting a pure bibliometric approach, the "knowledge" traced in the BKF is that produced and exchanged by the scientific community by means of publications and relevant citations. A description of the theoretical foundation of such a tool is presented together with its empirical testing over the scientific production of four different countries. The BKF can be part of yearly reports of science and technology indicators, aimed at informing research policy.
title: Corporate CO2 Offsetting in Small- and Medium-Seized Firms in Germany
title: MAGKS - Joint Discussion Paper Series in Economics
Creators: name: Engler, Daniel
name: Gutsche, Gunnar
name: Simixhiu, Amantia
name: Ziegler, Andreas
Publisher: name: Philipps-Universität Marburg
Year: 2021
Subjects: Corporate CO2 offsetting
corporate climate protection and pro-environmental activities
small- and medium-sized firms
Economics
Wirtschaft

description: Voluntary CO2 offsetting by individuals, firms, and organizations is increasingly considered as a direction of climate policy that is complementary to traditional approaches such as sub-sidies or CO2 taxes. Based on data from a large-scale survey among corporate decision mak-ers, this paper empirically examines corporate CO2 offsetting and its determinants in small- and medium-sized firms in Germany. Our descriptive analysis shows both a rather limited engagement in corporate CO2 offsetting as well as a strong lack of knowledge about its mechanism. The econometric analysis reveals that some firm-specific characteristics like the average age of the employees, firm size, and firm age matter for CO2 offsetting. However, the main estimation results refer to the relevance of general environment-related variables like the implementation of environmental product and service innovations or the share of employees that carry out environment-related tasks and especially of climate-related factors and activities. In particular, the implementation of climate targets and the participation in the EU Emissions Trading System (EU ETS) are strongly significantly positively correlated with CO2 offsetting. In line with similar findings at the individual level, these estimation results imply that corporate CO2 offsetting also does not substitute or crowd out other climate pro-tection and further pro-environmental activities, but rather complements them.