cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Opportunistic behaviour by private irrigators within a capacity-sharing regime
Creators: name: De Lange, Willem J.
name: Vink, Nick
name: De Lange, Willem J.
name: Vink, Nick
Publisher: name: Unknown
Year: 2003
Subjects: Resource /Energy Economics and Policy

description: The concept of capacity-sharing (as a specific type of demand-orientated water management strategy) is a relatively newcomer on the South African water management regime and much debate is currently under way regarding the viability of the concept for the South African context. One of the main features is that it decentralises and integrates water management to a much greater degree than state-dominated management regimes. However, as the concept of capacity-sharing allows a greater degree of decision-making autonomy to the private decision-maker, the question could be asked to what extent the management of a capacity-sharing regime would be exposed to opportunistic behaviour from private irrigators. If it is heavily exposed, there are considerable scope for opportunistic decision-making behaviour under private decision-makers and therefore problems of moral hazard / adverse selection and rent seeking could present itself. Therefore, the question arises what safety features do capacity sharing present to confine possible opportunistic decision-making practices. This article discusses two areas within a capacity-sharing regime that are likely to be exposed to opportunistic decision-making behaviour. Possible safety-features from capacity sharing to account for this type of behaviour are identified and discussed briefly. This article concludes with the notion that capacity sharing does feature some properties that could minimise opportunistic behaviour from private decision-makers.
SIDDIQ MO'MIN SHE'RLARIDA OTA VA ONA TIMSOLI
Creators: name: Yuldasheva, D.
name: Usmonova, Z.
Publisher: name: Zenodo
Year: 2024

description: Badiiy matn tahlili yuzasidan olib borilayotgan tadqiqotlarda konseptual tahlilga e’tibor tabora ortib bormoqda. Ushbu maqola  shoir Siddiq Mo‘min ijodida ota va ona konseptining ifodalanishiga bag‘ishlanib,  unda shoirning konsept qo’llash mahorati va ularning nutqiy ahamiyatiga bog‘liq tahlillar berilgan.
Optimal Trajectory Planning for Cinematography with Multiple Unmanned Aerial Vehicles
Creators: name: Alcántara, Alfonso
name: Capitán, Jesús
name: Cunha, Rita
name: Ollero, Aníbal
Publisher: name: arXiv
Year: 2020
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: This paper presents a method for planning optimal trajectories with a team of Unmanned Aerial Vehicles (UAVs) performing autonomous cinematography. The method is able to plan trajectories online and in a distributed manner, providing coordination between the UAVs. We propose a novel non-linear formulation for this challenging problem of computing multi-UAV optimal trajectories for cinematography; integrating UAVs dynamics and collision avoidance constraints, together with cinematographic aspects like smoothness, gimbal mechanical limits and mutual camera visibility. We integrate our method within a hardware and software architecture for UAV cinematography that was previously developed within the framework of the MultiDrone project; and demonstrate its use with different types of shots filming a moving target outdoors. We provide extensive experimental results both in simulation and field experiments. We analyze the performance of the method and prove that it is able to compute online smooth trajectories, reducing jerky movements and complying with cinematography constraints.
description: This paper has been published as: Optimal trajectory planning for cinematography with multiple Unmanned Aerial Vehicles. Alfonso Alcantara and Jesus Capitan and Rita Cunha and Anibal Ollero. Robotics and Autonomous Systems. 103778 (2021) 10.1016/j.robot.2021.103778
Updated BBN constraints on electromagnetic decays of MeV-scale particles
Creators: name: Depta, Paul Frederik
name: Hufnagel, Marco
name: Schmidt-Hoberg, Kai
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: In this work, we revise and update model-independent constraints from Big Bang Nucleosynthesis on MeV-scale particles $ϕ$ which decay into photons and/or electron-positron pairs. We use the latest determinations of primordial abundances and extend the analysis in arXiv:1808.09324 by including all spin-statistical factors as well as inverse decays, significantly strengthening the resulting bounds in particular for small masses. For a very suppressed initial abundance of $ϕ$, these effects become ever more important and we find that even a pure 'freeze-in' abundance can be significantly constrained. In parallel to this article, we release the public code ACROPOLIS which numerically solves the reaction network necessary to evaluate the effect of photodisintegration on the final light element abundances. As an interesting application, we re-evaluate a possible solution of the lithium problem due to the photodisintegration of beryllium and find that e.g. an ALP produced via freeze-in can lead to a viable solution.
description: 26 pages, 11 figures, inverse decays; v2: minor changes, conclusions unchanged, matches published version
An analysis of factors contributing to the use of an income equalisation deposit scheme by commercial farmers in South Africa
Creators: name: Lishman, J.-L.
name: Nieuwoudt, W. Lieb
name: Lishman, J.-L.
name: Nieuwoudt, W. Lieb
Publisher: name: Unknown
Year: 2003
Subjects: Agricultural Finance

description: Recent research suggests that an Income Equalisation Deposit (IED) scheme could be a feasible new risk management tool for commercial farmers in South Africa. This prompted a study of practicing consultants (tax experts) views on determining what types of farmers would be likely to use the scheme. During 2000, a postal survey of 24 consultants was conducted mainly in KwaZulu-Natal, and in the Maize Triangle and surrounding areas. Each consultant was to review nine scenarios (eight plus a control, giving 192 observations) and decide whether they would recommend an IED scheme for each scenario. A statistical experimental design was used to structure the scenarios, allowing for main and interaction effects between variables that could influence the potential use of an IED scheme. Discriminant analysis revealed that, ceteris paribus, farmers with higher annual net farm incomes (>R300,000), lower debt/asset ratios (<15%), more variable net farm incomes, and less off-farm income would most likely use an IED scheme. In terms of ranking, ceteris paribus, high risk maize farmers, intermediate risk maize farmers and high risk livestock farmers are more likely to use an IED scheme than are low risk maize farmers, low and intermediate risk livestock farmers and diversified farmers. These results support the use of an IED scheme as a risk management tool as higher risk farmers are more likely to make use of the scheme.
Measurements of $Λ^+_c$ Branching Fractions of Cabibbo-Suppressed Decay Modes involving $Λ$ and $Σ^{0}$
Creators: name: The BABAR Collaboration
name: Aubert, B.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We measure the branching ratios of the Cabibbo-suppressed decays $Λ^+_c$ $\to$ $Λ$ $K^+$ and $Λ^+_c$ $\to$ $Σ^{0}$ $K^+$ %(measured with improved accuracy). relative to the Cabibbo-favored decay modes $Λ^+_c$ $\to$ $Λ$ $π^+$ and $Λ^+_c$ $\to$ $Σ^{0}$ $π^+$ to be $ 0.044 \pm 0.004 (\textnormal{stat.}) \pm 0.003 \ (\textnormal{syst.})$ and $ 0.039 \pm 0.005 (\textnormal{stat.}) \pm 0.003 (\textnormal{syst.})$, respectively. We set an upper limit on the branching ratio at 90 % confidence level for $Λ^+_c$ $\to$ $Λ$ $K^+ π^+ π^-$ to be $ 4.1 \times 10^{-2}$ relative to $Λ^+_c$ $\to$ $Λ$ $π^+$ and for $Λ^+_c$ $\to$ $Σ^{0}$ $K^+ π^+ π^-$ to be $ 2.0 \times 10^{-2}$ relative to $Λ^+_c$ $\to$ $Σ^{0}$ $π^+$. We also measure the branching fraction for the Cabibbo-favored mode $Λ^+_c$ $\to$ $Σ^{0}$ $π^+$ relative to $Λ^+_c$ $\to$ $Λ$ $π^+$ to be $0.977 \pm 0.015 (\textnormal{stat.}) \pm 0.051 (\textnormal{syst.})$. This analysis was performed using a data sample with an integrated luminosity of 125 fb$^{-1}$ collected by the $BABAR$ detector at the PEP-II asymmetric-energy $B$ factory at SLAC.
description: 10 pages, 10 postscript figures, Published in Physics Review 75.052002
Decentralized Federated Learning via Mutual Knowledge Transfer
Creators: name: Li, Chengxi
name: Li, Gang
name: Varshney, Pramod K.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Machine Learning (cs.LG)
subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: FOS: Computer and information sciences

description: In this paper, we investigate the problem of decentralized federated learning (DFL) in Internet of things (IoT) systems, where a number of IoT clients train models collectively for a common task without sharing their private training data in the absence of a central server. Most of the existing DFL schemes are composed of two alternating steps, i.e., model updating and model averaging. However, averaging model parameters directly to fuse different models at the local clients suffers from client-drift especially when the training data are heterogeneous across different clients. This leads to slow convergence and degraded learning performance. As a possible solution, we propose the decentralized federated earning via mutual knowledge transfer (Def-KT) algorithm where local clients fuse models by transferring their learnt knowledge to each other. Our experiments on the MNIST, Fashion-MNIST, CIFAR-10, and CIFAR-100 datasets reveal that the proposed Def-KT algorithm significantly outperforms the baseline DFL methods with model averaging, i.e., Combo and FullAvg, especially when the training data are not independent and identically distributed (non-IID) across different clients.
description: Published in IEEE Internet of Things Journal
Factors affecting the loan status of sugarcane farmers using a graduated mortgage loan repayment scheme in KwaZulu-Natal
Creators: name: Mashatola, M.C.
name: Darroch, Mark A.G.
name: Mashatola, M.C.
name: Darroch, Mark A.G.
Publisher: name: Unknown
Year: 2003
Subjects: Agricultural Finance

description: Factors affecting whether or not 83 medium-scale sugarcane farmers using a graduated mortgage loan repayment scheme in KwaZulu-Natal were current or in arrears on loan repayments as at 31 March 2001 were analysed using a logit model. Results show that the estimated probability of a farmer in the scheme being current on loan repayments was higher for clients with higher levels of average annual farm gross turnover relative to loan size, and for clients with access to substantive off-farm income. This suggests that farm size (proxied by annual gross turnover) does matter when policymakers in South Africa consider future similar schemes designed to improve access to commercial farmland by people that previously could not buy farmland. Access to off-farm income could also be considered as a criterion in selecting potential farmers for such schemes, as it helps to provide additional liquidity to fund future operations and debt repayments.
General method for determining the boundary layer thickness in nonequilibrium flows
Creators: name: Griffin, Kevin Patrick
name: Fu, Lin
name: Moin, Parviz
Publisher: name: arXiv
Year: 2020
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: While the computation of the boundary-layer thickness is straightforward for canonical equilibrium flows, there are no established definitions for general non-equilibrium flows. In this work, a method is developed based on a local reconstruction of the "inviscid" velocity profile $U_I[y]$ resulting from the application of the Bernoulli equation in the wall-normal direction. The boundary-layer thickness $δ_{99}$ is then defined as the location where $U/U_I = 0.99$, which is consistent with its classical definition for the zero-pressure-gradient boundary layers (ZPGBLs). The proposed local-reconstruction method is parameter free and can be deployed for both internal and external flows without resorting to an iterative procedure, numerical integration, or numerical differentiation. The superior performance of the local-reconstruction method over various existing methods is demonstrated by applying the methods to laminar and turbulent boundary layers and two flows over airfoils. Numerical experiments reveal that the local-reconstruction method is more accurate and more robust than existing methods, and it is applicable for flows over a wide range of Reynolds numbers.
description: Accepted to Physical Review Fluids
The Three-Dimensional Circumstellar Environment of SN 1987A
Creators: name: Sugerman, Ben E. K.
name: Crotts, Arlin P. S.
name: Kunkel, William E.
name: Heathcote, Stephen R.
name: Lawrence, Stephen S.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present the detailed construction and analysis of the most complete map to date of the circumstellar environment around SN 1987A, using ground and space-based imaging from the past 16 years. PSF-matched difference-imaging analyses of data from 1988 through 1997 reveal material between 1 and 28 ly from the SN. Careful analyses allows the reconstruction of the probable circumstellar environment, revealing a richly-structured bipolar nebula. An outer, double-lobed ``Peanut,'' which is believed to be the contact discontinuity between red supergiant and main sequence winds, is a prolate shell extending 28 ly along the poles and 11 ly near the equator. Napoleon's Hat, previously believed to be an independent structure, is the waist of this Peanut, which is pinched to a radius of 6 ly. Interior to this is a cylindrical hourglass, 1 ly in radius and 4 ly long, which connects to the Peanut by a thick equatorial disk. The nebulae are inclined 41\degr south and 8\degr east of the line of sight, slightly elliptical in cross section, and marginally offset west of the SN. From the hourglass to the large, bipolar lobes, echo fluxes suggest that the gas density drops from 1--3 cm^{-3} to >0.03 cm^{-3}, while the maximum dust-grain size increases from ~0.2 micron to 2 micron, and the Si:C dust ratio decreases. The nebulae have a total mass of ~1.7 Msun. The geometry of the three rings is studied, suggesting the northern and southern rings are located 1.3 and 1.0 ly from the SN, while the equatorial ring is elliptical (b/a < 0.98), and spatially offset in the same direction as the hourglass.
description: Accepted for publication in the ApJ Supplements. 38 pages in apjemulate format, with 52 figures
Information Hiding Using Matroid Theory
Creators: name: Freij-Hollanti, Ragnar
name: Kuznetsova, Olga
Publisher: name: arXiv
Year: 2020
Subjects: subject: Combinatorics (math.CO)
subject: Information Theory (cs.IT)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: Inspired by problems in Private Information Retrieval, we consider the setting where two users need to establish a communication protocol to transmit a secret without revealing it to external observers. This is a question of how large a linear code can be, when it is required to agree with a prescribed code on a collection of coordinate sets. We show how the efficiency of such a protocol is determined by the derived matroid of the underlying linear communication code. Furthermore, we provide several sufficient combinatorial conditions for when no secret transmission is possible.
Fertilizer trade and pricing in Uganda
Creators: name: Omamo, Steven Were
name: Omamo, Steven Were
Publisher: name: Unknown
Year: 2003
Subjects: Agribusiness

description: Liberalized fertilizer markets in eastern Africa typically deliver fertilizer to smallholder farming regions at prices that render its use unprofitable. Simultaneously, faced with little demand for fertilizer in these regions, fertilizer traders appear unwilling to invest in measures that might reduce farm-gate prices. A basic question throughout the region is therefore how to cost-effectively increase smallholders' access to fertilizer, under conditions of liberalized and privatised trade in the input. This paper explores that question for Uganda using data from a wide-ranging study of Uganda's fertilizer sub-sector. The prevailing system of fertilizer procurement and distribution is found to imply a market structure dominated by retail-level trade, high prices, and low net margins. The study concludes that there is no inherent pressures in the extant system of fertilizer procurement and distribution toward development of a wholesaling backbone that might allow capture of scale economies. But with imaginative and sustained investments in institutional innovation and strengthening, there is scope to reduce prices and increase net trading margins.
Measuring Z' couplings at the LHC
Creators: name: Petriello, Frank
name: Quackenbush, Seth
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the properties of potential new Z' gauge bosons produced through the Drell-Yan mechanism at the LHC. Our analysis is performed using a fully differential next-to-leading order QCD calculation with spin correlations, interference effects, and experimental acceptances included. We examine the distinguishability of different models and the feasibility of extracting general coupling information with statistical, residual scale, and current parton distribution function error estimates included. We extend a previous parametrization of Z' couplings to include parity-violating coupling combinations, and introduce a convenient technique for simulating new gauge bosons on-peak using the concept of basis models. We illustrate our procedure using several example Z' models. We find that one can extract reliably four combinations of generation-independent quark and lepton couplings in our analysis. For a Z' mass of 1.5 TeV, one can determine coupling information very well assuming 100 fb^{-1} of integrated luminosity, and a precise measurement becomes possible with 1 ab^{-1} at the SLHC. For a 3 TeV mass, a reasonable determination requires the SLHC.
description: 22 pgs., 6 figs; refs and discussion added
Gluonic Tetracharm Configuration of $X(6900)$
Creators: name: Wan, Bing-Dong
name: Qiao, Cong-Feng
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Recently, a new hadronic structure at around $6.9$ GeV was observed in an LHCb experiment. From its limited yet known decay mode, one could still determine that it contains at least four charm quarks and hence belongs to the category of exotic state. This finding indicates for the first time the tetracharm exotic states and is therefore quite importance. In this letter, we propose a nature hybrid interpretation for the structure of $X(6900)$, i.e. in $[\bar{3}_c]_{c c}\otimes[8_c]_{G}\otimes[3_c]_{\bar{c} \bar{c}}$ configuration with $J^{PC}=0^{++}$, and by using the QCD Sum Rule technique we performed mass spectrum calculation. The results showed that the observed $X(6900)$ could be a gluonic tetracharm state, and some other structures may exist, e.g., one around $7.2$ GeV in the tetracharm hybrid configuration and with $J^{PC}=0^{-+}$. We also predict the tetrabottom hybrid states, leaving for future experiment.
description: 14 pages, 4 figures, published in PLB
Behavior of shell-model configuration moments
Creators: name: Teran, Edgar
name: Johnson, Calvin W.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: An important input into reaction theory is the density of states or the level density. Spectral distribution theory (also known as nuclear statistical spectroscopy) characterizes the secular behavior of the density of states through moments of the Hamiltonian. One particular approach is to partition the model space into subspaces and find the moments in those subspaces; a convenient choice of subspaces are spherical shell-model configurations. We revisit these configuration moments and find, for complete $0\hbarω$ many-body spaces, the following behaviors: (a) the configuration width is nearly constant for all configurations; (b) the configuration asymmetry or third moment is strongly correlated with the configuration centroid; (c) the configuration fourth moment, or excess is linearly related to the square to the configuration asymmetry. Such universal behavior may allow for more efficient modeling of the density of states in a shell-model framework.
description: 12 pages, 8 figures
Creating a new valuation tool for South African agricultural cooperatives
Creators: name: Geyser, Mariette
name: Hassan, Rashid M.
name: Geyser, Mariette
name: Hassan, Rashid M.
Publisher: name: Unknown
Year: 2003
Subjects: Agribusiness

description: Long-term shareholder wealth is equally important for all profit seeking organizations, regardless of their size. This paper examines introducing Economic Value Added (EVA) as a performance measure for agribusinesses and co-ops in South Africa. EVA is an effective measure of the quality of managerial decisions as well as a reliable indicator of an enterprise's value growth in future. The question posed is whether South African agribusinesses and cooperatives are capable of creating shareholder and member value after the deregulation of the agricultural markets.
Centrifugal Breakout of Magnetically Confined Line-Driven Stellar Winds
Creators: name: ud-Doula, A.
name: Townsend, R. H. D.
name: Owocki, S. P.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present 2D MHD simulations of the radiatively driven outflow from a rotating hot star with a dipole magnetic field aligned with the star's rotation axis. We focus primarily on a model with moderately rapid rotation (half the critical value), and also a large magnetic confinement parameter, $η_{\ast} \equiv B_{\ast}^2 R_{\ast}^{2} / \dot{M} V_{\infty} = 600$. The magnetic field channels and torques the wind outflow into an equatorial, rigidly rotating disk extending from near the Kepler corotation radius outwards. Even with fine-tuning at lower magnetic confinement, none of the MHD models produce a stable Keplerian disk. Instead, material below the Kepler radius falls back on to the stellar surface, while the strong centrifugal force on material beyond the corotation escape radius stretches the magnetic loops outwards, leading to episodic breakout of mass when the field reconnects. The associated dissipation of magnetic energy heats material to temperatures of nearly $10^{8}$K, high enough to emit hard (several keV) X-rays. Such \emph{centrifugal mass ejection} represents a novel mechanism for driving magnetic reconnection, and seems a very promising basis for modeling X-ray flares recently observed in rotating magnetic Bp stars like $σ$ Ori E.
description: 5 pages, 3 figures, accepted by ApJL
Modeling interactions for resonant p-wave scattering
Creators: name: Pricoupenko, Ludovic
Publisher: name: arXiv
Year: 2005
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: In view of recent experiments on ultra-cold polarized fermions, the zero-range potential approach is generalized to situations where two-body scattering is resonant in the p-wave channel. We introduce a modified scalar product which reveals a deep relation between the geometry of the Hilbert space and the interaction. This formulation is used to obtain a simple interpretation for the transfer rates between atomic and molecular states within a two branches picture of the many-body system close to resonance. At resonance, the energy of the dilute gas is found to vary linearly with density.
description: 4 pages
How Large Are the Welfare Gains from Technological Innovation Induced by Environmental Policies?
Creators: name: Parry, Ian W.H.
name: Pizer, William A.
name: Fischer, Carolyn
name: Parry, Ian W.H.
name: Pizer, William A.
name: Fischer, Carolyn
Publisher: name: Unknown
Year: 2002
Subjects: subject: Environmental Economics and Policy
subject: innovation
subject: welfare
subject: regulation
subject: endogenous
subject: technological
subject: change
subject: R&D

description: This paper examines whether the welfare gains from technological innovation that reduces future abatement costs are larger or smaller than the "Pigouvian" welfare gains from optimal pollution control. The relative welfare gains from innovation depend on three key factors ¾ the initially optimal level of abatement, the speed at which innovation reduces future abatement costs, and the discount rate. We calculate the welfare gains from innovation under a variety of different scenarios. Mostly they are less than the Pigouvian welfare gains. To be greater, innovation must reduce abatement costs substantially and quickly and the initially optimal abatement level must be fairly modest.
Transferable Graph Optimizers for ML Compilers
Creators: name: Zhou, Yanqi
name: Roy, Sudip
name: Abdolrashidi, Amirali
name: Wong, Daniel
name: Ma, Peter
name: Xu, Qiumin
name: Liu, Hanxiao
name: Phothilimthana, Phitchaya Mangpo
name: Wang, Shen
name: Goldie, Anna
name: Mirhoseini, Azalia
name: Laudon, James
Publisher: name: arXiv
Year: 2020
Subjects: subject: Machine Learning (cs.LG)
subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: FOS: Computer and information sciences

description: Most compilers for machine learning (ML) frameworks need to solve many correlated optimization problems to generate efficient machine code. Current ML compilers rely on heuristics based algorithms to solve these optimization problems one at a time. However, this approach is not only hard to maintain but often leads to sub-optimal solutions especially for newer model architectures. Existing learning based approaches in the literature are sample inefficient, tackle a single optimization problem, and do not generalize to unseen graphs making them infeasible to be deployed in practice. To address these limitations, we propose an end-to-end, transferable deep reinforcement learning method for computational graph optimization (GO), based on a scalable sequential attention mechanism over an inductive graph neural network. GO generates decisions on the entire graph rather than on each individual node autoregressively, drastically speeding up the search compared to prior methods. Moreover, we propose recurrent attention layers to jointly optimize dependent graph optimization tasks and demonstrate 33%-60% speedup on three graph optimization tasks compared to TensorFlow default optimization. On a diverse set of representative graphs consisting of up to 80,000 nodes, including Inception-v3, Transformer-XL, and WaveNet, GO achieves on average 21% improvement over human experts and 18% improvement over the prior state of the art with 15x faster convergence, on a device placement task evaluated in real systems.
description: arXiv admin note: text overlap with arXiv:1910.01578
Niemöller, Martin: Reden, Predigten, Denkanstöße 1964-1976
Creators: name: Kg.
Publisher: name: Ökumenische Rundschau
Year: 2025

description: Ökumenische Rundschau, Bd. 26 Nr. 3 (1977): Ökumenische Rundschau, Band 26, Heft 3
An Analysis of Global Timber Markets
Creators: name: Sohngen, Brent
name: Mendelsohn, Robert
name: Sedjo, Roger A.
name: Lyon, Kenneth S.
name: Sohngen, Brent
name: Mendelsohn, Robert
name: Sedjo, Roger A.
name: Lyon, Kenneth S.
Publisher: name: Unknown
Year: 1997
Subjects: subject: Resource /Energy Economics and Policy
subject: global timber markets
subject: forest plantations
subject: model
subject: forecast

description: This paper presents a model of global timber markets that captures the evolution of a broad array of forest resources and timber market margins over time. These margins include the inaccessible northern and tropical margins, plantation establishment, and timberland management. A baseline case is presented and discussed. Five alternative scenarios are then presented. These scenarios allow us to consider several important questions about timber market behavior and the future supply of industrial fiber: (1) What happens along the northern and the tropical inaccessible margins? (2) What role do timber plantations play? and (3) How do shifts in management intensity interact with market forces? The baseline case suggests that both prices and harvests rise over the next 150 years, with most of the increased harvest coming from existing and newly established plantations. Future gains in harvests result mainly from intensification of management, through additional plantation establishment and higher levels of management on selected forests rather than higher harvests in currently inaccessible forests. Prices and harvests are most sensitive to alternative demand and plantation establishment scenarios, and less sensitive to costs of accessing extensive forests.
Essays on new venture survival and growth
Creators: name: Thornhill, Stewart
Publisher: name: University of British Columbia
Year: 2009

description: This thesis is comprised of three essays dealing with the survival and growth of business enterprises. The first paper (Chapter 2) explores a long-standing question in corporate venture management: How closely should a corporate parent link itself with its own venture? We challenge the conventional view that autonomy is best for venture growth by arguing that access to the parent's resources and capabilities (i.e., a "tight fit") is essential if a venture is to demonstrate competitive advantage. Data from 97 Canadian corporate ventures generally support the "tight-fit" hypothesis. We also find empirical support for the proposition that the relationship between a corporate parent and its venture(s) evolves over time; economic ties diminish with venture maturity, relational ties remain intact. The next paper (Chapter 3) models the growth and decline of young firms as a function of their initial asset stocks, initial capabilities, rate of capability development, rate of asset depletion, and failure threshold. Data from 246 Canadian corporate bankruptcies confirm that young firms fail due to insufficient organizational capital at start-up and inadequacies in managerial knowledge, financial management skills, and marketing abilities. Older firms, on the other hand, are more prone to failure due to environmental change. The final paper (Chapter 4) utilizes detailed survey data from a proportionally stratified, representative sample of 3,000 Canadian firms to evaluate industry- and firm-level determinants of young firm growth. The competitive environment is found to be a poor predictor of the growth of young firms. In general, growth of the seven to ten year old firms in our study did not follow the growth trends of the industries in which they operated. Among firm strategies, innovation was the strongest predictor of revenue growth. Also of note was the finding that different types of managerial experience were significant in different sectors. For service firms, general management experience was positively associated with growth, while for goods-producing firms industry experience was a more important factor.
Connecting Dense Gas Tracers of Star Formation in our Galaxy to High-z Star Formation
Creators: name: Wu, Jingwen
name: Evans, Neal J.
name: Gao, Yu
name: Solomon, Philip M.
name: Shirley, Yancy L.
name: Bout, Paul A. Vanden
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Observations have revealed prodigious amounts of star formation in starburst galaxies as traced by dust and molecular emission, even at large redshifts. Recent work shows that for both nearby spiral galaxies and distant starbursts, the global star formation rate, as indicated by the infrared luminosity, has a tight and almost linear correlation with the amount of dense gas as traced by the luminosity of HCN. Our surveys of Galactic dense cores in HCN 1-0 emission show that this correlation continues to a much smaller scale, with nearly the same ratio of infrared luminosity to HCN luminosity found over 7-8 orders of magnitude in L_IR, with a lower cutoff around 10^{4.5} L_sun of infrared luminosity. The linear correlation suggests that we may understand distant star formation in terms of the known properties of local star-forming regions. Both the correlation and the luminosity cutoff can be explained if the basic unit of star formation in galaxies is a dense core, similar to those studied in our Galaxy.
description: 10 pages, 2 figures. In press for ApJ Letters
Science at the Seaside - Digitisation of Ilfracombe Museum Collection - Ehive (2015)
Creators: name: Hadjiafxendi, Kyriaki
Publisher: name: BathSPAdata
Year: 2021
Subjects: subject: 200503 British and Irish Literature
subject: FOS: Languages and literature
subject: 60205 Marine and Estuarine Ecology (incl. Marine Ichthyology)
subject: FOS: Biological sciences

description: The material referenced in this item is located externally at the above linked website, and can be viewed in full by accessing via the provided link.

Science at the Seaside is a collaboration between Ilfracombe Museum, Bath Spa University and the University of Exeter, which proposes a new and original understanding of the interlinked growth of popular science and coastal tourism during the Victorian period, with the different outputs producing original insights into the Victorian fascination with natural history.

As part of Science at the Seaside, Ilfracombe Museum digitised circa 2000 items covering items relating to seaside science and the growth of Ilfracombe as a tourist resort in the nineteenth- and early-twentieth centuries. E-Hive is a web-based collection cataloguing system used by many museums to publish their collections online. This was the first time that Ilfracombe Museum had digitised part of its collections and made them publicly available online from January 2015. As of February 2021, there are 3326 items on eHive as the museum has continued to add digitised items from the collection.
As project leads, Hadjiafxendi, Plunkett and the museum curator oversaw the selection of items for digitisation from Ilfracombe Museum archives; the selection was based on research into the collection undertaken for the exhibition and the availability of items relating to the growth of Ilfracombe as a seaside resort in the nineteenth-century.
Accidents Waiting to Happen: Liability Policy and Toxic Pollution Releases
Creators: name: Alberini, Anna
name: Austin, David H.
name: Alberini, Anna
name: Austin, David H.
Publisher: name: Unknown
Year: 1999
Subjects: subject: Environmental Economics and Policy
subject: strict liability
subject: toxic spills
subject: policy endogeneity

description: Proponents of environmental policies based on liability assert that strict liability imposed on the polluter will induce firms to handle hazardous wastes properly and to avoid disposing them into the environment. Economic theory and a few well-publicized cases, however, suggest that a number of factors may dilute the incentives posed by strict liability. In this paper, we run regressions relating unintended releases of pollution into the environment (aggregated at the state level, and followed over nine years from 1987 to 1995) to the imposition of strict liability on the polluter, exploiting variation across states in the liability provisions of their mini-Superfund laws, and in the years these were adopted. We experiment with instrumental variable estimation, fixed effects, and endogenous switching, and find that only after we explicitly model the endogeneity of states' liability laws is strict liability seen as reducing the seriousness of spills and releases. We also find evidence consistent with the notion that under strict liability, firms may spin off into, or delegate riskier production processes to, smaller firms, which are partially sheltered from liability. This tendency appears to be widespread.
Fishing Quota Markets
Creators: name: Newell, Richard G.
name: Sanchirico, James N.
name: Kerr, Suzi
name: Newell, Richard G.
name: Sanchirico, James N.
name: Kerr, Suzi
Publisher: name: Unknown
Year: 2002
Subjects: subject: Resource /Energy Economics and Policy
subject: tradable permits
subject: individual transferable quota
subject: fisheries
subject: policy

description: Fisheries worldwide continue to suffer from the negative consequences of open access. In 1986, New Zealand responded by establishing an individual transferable quota (ITQ) system that by 1998 included 33 species and more than 150 markets for fishing quotas. We assess these markets in terms of trends in market activity, price dispersion, and the fundamentals determining quota prices. We find that market activity is sufficiently high to support a competitive market and that price dispersion has decreased over time. Using a 15-year panel dataset, we also find evidence of economically rational behavior through the relationship between quota lease and sale prices and fishing output and input prices, ecological variability, and market interest rates. Controlling for these factors, our results show an increase in quota prices, consistent with increased profitability. Overall, the results suggest these markets are operating reasonably well, implying that ITQs can be effective instruments for efficient fisheries management.
The Architecture and Measurement of an Ecosystem Services Index
Creators: name: Banzhaf, H. Spencer
name: Boyd, James
name: Banzhaf, H. Spencer
name: Boyd, James
Publisher: name: Unknown
Year: 2005
Subjects: subject: Environmental Economics and Policy
subject: ecosystem services
subject: Green GDP
subject: index numbers
subject: ecological economics

description: This paper describes the construction of an ecological services index (ESI). An ESI is meant to summarize and track over time the magnitude of beneficial services arising from the natural environment. A central task of this paper is to define rigorously ecosystem services so that services can be counted in an economically and ecologically defensible manner - a requirement if ecological contributions to welfare are to be incorporated into the national accounts. This paper advocates a particular economic structure and relates it to index theory and makes concrete recommendations for the measurement of such an index.
Particle Acceleration, Magnetic Field Generation, and Associated Emission in Collisionless Relativistic Jets
Creators: name: Nishikawa, K. -I.
name: Mizuno, Y.
name: Fishman, G. J.
name: Hardee, P.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma-ray bursts (GRBs), and Galactic microquasar systems usually have power-law emission spectra. Recent PIC simulations using injected relativistic electron-ion (electro-positron) jets show that acceleration occurs within the downstream jet. Shock acceleration is a ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, other two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields. These magnetic fields contribute to the electron's transverse deflection behind the jet head. The ``jitter'' radiation from deflected electrons has different properties than synchrotron radiation which assumes a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.
description: 4 pages, 3 figures, contributed talk at the workshop: High Energy Phenomena in Relativistic Outflows (HEPRO), Dublin, 24-28 September 2007. Fig. 3 is replaced by the correct version
Science at the Seaside - Blog - ‘Science at the Seaside’: Experiential learning and public engagement (2015) [Contextualising information]
Creators: name: Hadjiafxendi, Kyriaki
name: Plunkett, John
Publisher: name: BathSPAdata
Year: 2021
Subjects: subject: 200503 British and Irish Literature
subject: FOS: Languages and literature
subject: Marine Biology

description: The material referenced in this item is located externally at the above linked website, and can be viewed in full by accessing via the provided link.

Science at the Seaside is a collaboration between Ilfracombe Museum, Bath Spa University and the University of Exeter, which proposes a new and original understanding of the interlinked growth of popular science and coastal tourism during the Victorian period, with the different outputs producing original insights into the Victorian fascination with natural history.

This item contains a link to a blog co-written by Dr Kyriaki Hadjiafxendi and Professor John Plunkett about the Science at the Seaside project, included as contextualising information.
StackRec: Efficient Training of Very Deep Sequential Recommender Models by Iterative Stacking
Creators: name: Wang, Jiachun
name: Yuan, Fajie
name: Chen, Jian
name: Wu, Qingyao
name: Yang, Min
name: Sun, Yang
name: Zhang, Guoxiao
Publisher: name: arXiv
Year: 2020
Subjects: subject: Information Retrieval (cs.IR)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Deep learning has brought great progress for the sequential recommendation (SR) tasks. With advanced network architectures, sequential recommender models can be stacked with many hidden layers, e.g., up to 100 layers on real-world recommendation datasets. Training such a deep network is difficult because it can be computationally very expensive and takes much longer time, especially in situations where there are tens of billions of user-item interactions. To deal with such a challenge, we present StackRec, a simple, yet very effective and efficient training framework for deep SR models by iterative layer stacking. Specifically, we first offer an important insight that hidden layers/blocks in a well-trained deep SR model have very similar distributions. Enlightened by this, we propose the stacking operation on the pre-trained layers/blocks to transfer knowledge from a shallower model to a deep model, then we perform iterative stacking so as to yield a much deeper but easier-to-train SR model. We validate the performance of StackRec by instantiating it with four state-of-the-art SR models in three practical scenarios with real-world datasets. Extensive experiments show that StackRec achieves not only comparable performance, but also substantial acceleration in training time, compared to SR models that are trained from scratch. Codes are available at https://github.com/wangjiachun0426/StackRec.
Meta Analysis in Model Implementation: Choice Sets and the Valuation of Air Quality Improvements
Creators: name: Banzhaf, H. Spencer
name: Smith, V. Kerry
name: Banzhaf, H. Spencer
name: Smith, V. Kerry
Publisher: name: Unknown
Year: 2003
Subjects: subject: Environmental Economics and Policy
subject: meta analysis
subject: random utility model
subject: choice set
subject: air quality
subject: housing

description: We document the sensitivity of welfare estimates derived from discrete choice models to assumptions about the choice set. Such assumptions can affect welfare estimates through both the estimated parameters of the model and, conditional on the parameters, the substitution among alternatives. Our analysis involves estimates of the benefits of air quality improvements in Los Angeles based on discrete choices of neighborhood and housing. We further illustrate the use of meta analysis to document and summarize voluminous information derived from repeated sensitivity analyses.
Through the Looking-Glass: Alice's Adventures in Mirror World
Creators: name: Berezhiani, Zurab
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We briefly review the concept of a parallel `mirror' world which has the same particle physics as the observable world and couples to the latter by gravity and perhaps other very weak forces. The nucleosynthesis bounds demand that the mirror world should have a smaller temperature than the ordinary one. By this reason its evolution should substantially deviate from the standard cosmology as far as the crucial epochs like baryogenesis, nucleosynthesis etc. are concerned. In particular, we show that in the context of certain baryogenesis scenarios, the baryon asymmetry in the mirror world should be larger than in the observable one. Moreover, we show that mirror baryons could naturally constitute the dominant dark matter component of the Universe, and discuss its cosmological implications.
description: Published in Ian Kogan Memorial Collection "From Fields to Strings: Circumnavigating Theoretical Physics", Eds. M. Shifman et al., World Scientific, Singapore, vol. 3, pp. 2147-2195. 49pp., 8 Figures
ALISHER NAVOIY "XAMSA" DOSTONIDA HARF (KITOBAT) SAN'ATINING QO`LLANILISHI
Creators: name: Saydullayeva, Fotima
Publisher: name: Zenodo
Year: 2024

description: Muallif maqolani yaratar ekan,Alisher Navoiy ijodiga cheksiz bir hurmat bilan qaraydi.Alisher Navoiy “Xamsa” asarining dastlabki dostoni “Hayrat ul-abror” dostoni tarkibidagi arabcha harflarni tahlil qilishga harakat qiladi. Maqola arab yozuvidagi kitobat san’atini tahlil qilganligi bilan qimmatlidir.
Vector coherent state theory of the generic representations of so(5) in an so(3) basis
Creators: name: Turner, P. S.
name: Rowe, D. J.
name: Repka, J.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Mathematical Physics (math-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: For applications of group theory in quantum mechanics, one generally needs explicit matrix representations of the spectrum generating algebras that arise in bases that reduce the symmetry group of some Hamiltonian of interest. Here we use vector coherent state techniques to develop an algorithm for constructing the matrices for arbitrary finite-dimensional irreps of the SO(5) Lie algebra in an SO(3) basis. The SO(3) subgroup of SO(5) is defined by regarding SO(5) as linear transformations of the five-dimensional space of an SO(3) irrep of angular momentum two. A need for such irreps arises in the nuclear collective model of quadrupole vibrations and rotations. The algorithm has been implemented in MAPLE, and some tables of results are presented.
description: 20 pages, uses multirow.sty, submitted to J. Math. Phys