cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Specified resilience value of alternative forest management adaptations to storms
Creators: name: Hahn, Thomas
name: Eggers, Jeannette
name: Subramanian, Narayanan
name: Caicoya, Astor Toraño
name: Uhl, Enno
name: Snäll, Tord
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Ecology
subject: FOS: Biological sciences
subject: Science Policy

description: Resilient ecosystems provide natural insurance value, or resilience value, to the landowner and to society at large. In response to global calls for integrating biodiversity in sector policy and planning, we analysed the specified resilience value by simulating three storm regimes and five management scenarios: Business As Usual/BAU (spruce-dominance), Spruce Monoculture, More Broadleaves, Continuous Cover Forestry (CCF), and No Thinnings. The forest decision support system Heureka RegWise was used to simulate the effects of storms on forest dynamics and Net Present Value (NPV). No Thinnings, CCF and More Broadleaves were more resilient to storms (reduced damage cost) compared to BAU. BAU had the highest NPV only if storms are ignored, a common assumption in today’s forest planning. Given storms, No Thinnings maximises NPV on landscape level. On the 20% most vulnerable plots the NPV was much higher for No Thinnings and slightly higher for CCF and More Broadleaves, compared to BAU. CCF and More Broadleaves also provide nature-based solutions (co-benefits) including public goods. However, forestry adaptations to storms are slow in Sweden, in contrast to e.g. German state forestry which emphasises maximising tree growth and resilience to several stresses and disturbances rather than NPV optimisation.
Perturbations in a regular bouncing Universe
Creators: name: Battefeld, T. J.
name: Geshnizjani, G.
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Astrophysics (astro-ph)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We consider a simple toy model of a regular bouncing universe. The bounce is caused by an extra time-like dimension, which leads to a sign flip of the $ρ^2$ term in the effective four dimensional Randall Sundrum-like description. We find a wide class of possible bounces: big bang avoiding ones for regular matter content, and big rip avoiding ones for phantom matter. Focusing on radiation as the matter content, we discuss the evolution of scalar, vector and tensor perturbations. We compute a spectral index of $n_s=-1$ for scalar perturbations and a deep blue index for tensor perturbations after invoking vacuum initial conditions, ruling out such a model as a realistic one. We also find that the spectrum (evaluated at Hubble crossing) is sensitive to the bounce. We conclude that it is challenging, but not impossible, for cyclic/ekpyrotic models to succeed, if one can find a regularized version.
description: v3: 10 pages, 1 figure, section III revised, conclusions changed, references added, typos corrected; v4: numerics added, identical with version accepted in PRD
Pedagogy Collection, Access Microbiology
Creators: name: Efthimiou, Georgios
name: authors, Various
Publisher: name: National Teaching Repository
Year: 2024
Subjects: classificationCode: 310799
subject: Microbiology not elsewhere classified

description: This document is a list of pedagogical papers published in Access Microbiology (Microbiology Society, UK) since 2019. They are part of the Pedagogy Collection: https://www.microbiologyresearch.org/content/pedagogyDr Georgios Efthimiou from Hull York Medical School was Pedagogy Editor for Access Microbiology and acts as a curator for this list on the NTR.The purpose of the Pedagogy Collection is to help microbiology/bioscience educators in the UK and abroad in spicing up their teaching or outreach activities with new innovative ideas!
Folding model analysis of proton scattering from mirror nuclei $^{18}$Ne and $^{18}$O
Creators: name: Gupta, D.
name: Basu, D. N.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The elastic and inelastic scattering of protons from mirror nuclei $^{18}$Ne and $^{18}$O are studied in a folding model approach. For comparison, two different effective interactions are folded with Hartree-Fock densities to obtain the nuclear interaction potentials. Both of them provide equivalent descriptions to the data and the deformation parameters extracted from inelastic scattering are reasonable. The density dependence parameters obtained from nuclear matter calculations and used for present analysis also provide a good estimate for the nuclear mean free path. The present formalism unifies radioactivity, nuclear matter and nuclear scattering.
description: 12 pages including 5 figures
Intersecting hypersurfaces in AdS and Lovelock gravity
Creators: name: Gravanis, Elias
name: Willison, Steven
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Colliding and intersecting hypersurfaces filled with matter (membranes) are studied in the Lovelock higher order curvature theory of gravity. Lovelock terms couple hypersurfaces of different dimensionalities, extending the range of possible intersection configurations. We restrict the study to constant curvature membranes in constant curvature AdS and dS background and consider their general intersections. This illustrates some key features which make the theory different to the Einstein gravity. Higher co-dimension membranes may lie at the intersection of co-dimension 1 hypersurfaces in Lovelock gravity; the hypersurfaces are located at the discontinuities of the first derivative of the metric, and they need not carry matter. The example of colliding membranes shows that general solutions can only be supported by (spacelike) matter at the collision surface, thus naturally conflicting with the dominant energy condition (DEC). The imposition of the DEC gives selection rules on the types of collision allowed. When the hypersurfaces don't carry matter, one gets a soliton-like configuration. Then, at the intersection one has a co-dimension 2 or higher membrane standing alone in AdS-vacuum spacetime \emph{without conical singularities.} Another result is that if the number of intersecting hypersurfaces goes to infinity the limiting spacetime is free of curvature singularities if the intersection is put at the boundary of each AdS bulk.
description: 35 pages, 1 figure. Published version
Disparate Impact of Artificial Intelligence Bias in Ridehailing Economy's Price Discrimination Algorithms
Creators: name: Pandey, Akshat
name: Caliskan, Aylin
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computers and Society (cs.CY)
subject: Artificial Intelligence (cs.AI)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Ridehailing applications that collect mobility data from individuals to inform smart city planning predict each trip's fare pricing with automated algorithms that rely on artificial intelligence (AI). This type of AI algorithm, namely a price discrimination algorithm, is widely used in the industry's black box systems for dynamic individualized pricing. Lacking transparency, studying such AI systems for fairness and disparate impact has not been possible without access to data used in generating the outcomes of price discrimination algorithms. Recently, in an effort to enhance transparency in city planning, the city of Chicago regulation mandated that transportation providers publish anonymized data on ridehailing. As a result, we present the first large-scale measurement of the disparate impact of price discrimination algorithms used by ridehailing applications. The application of random effects models from the meta-analysis literature combines the city-level effects of AI bias on fare pricing from census tract attributes, aggregated from the American Community Survey. An analysis of 100 million ridehailing samples from the city of Chicago indicates a significant disparate impact in fare pricing of neighborhoods due to AI bias learned from ridehailing utilization patterns associated with demographic attributes. Neighborhoods with larger non-white populations, higher poverty levels, younger residents, and high education levels are significantly associated with higher fare prices, with combined effect sizes, measured in Cohen's d, of -0.32, -0.28, 0.69, and 0.24 for each demographic, respectively. Further, our methods hold promise for identifying and addressing the sources of disparate impact in AI algorithms learning from datasets that contain U.S. geolocations.
description: 16 pages, 3 tables, 8 figures
Chlorhexidine - Molecule of the Month August 2020 [Archived version]
Creators: name: Ke, Yu Xi
name: Orellana, Claudia
Publisher: name: figshare
Year: 2020
Subjects: subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences

description: This is the Molecule of the Month entry for August 2020 about chlorhexidine. It is a pdf archive version of the HTML webpage.
Pedagogy Collection, Access Microbiology
Creators: name: authors, Various
name: Efthimiou, Georgios
Publisher: name: National Teaching Repository
Year: 2023
Subjects: classificationCode: 310799
subject: Microbiology not elsewhere classified

description: This document is a list of pedagogical papers published in Access Microbiology (Microbiology Society, UK) since 2019. They are part of the Pedagogy Collection: https://www.microbiologyresearch.org/content/pedagogy 

Dr Georgios Efthimiou from Hull York Medical School is currently a Pedagogy Editor for Access Microbiology and will act as a curator for this list on NTR, updating it every 2-3 months. 

The purpose of this Collection is to help microbiology/bioscience educators in the UK and abroad in spicing up their teaching or outreach activities with new innovative ideas!
The timing of evaluation of genebank accessions and the effects of biotechnology
Creators: name: Koo, Bonwoo
name: Wright, Brian D.
name: Koo, Bonwoo
name: Wright, Brian D.
Publisher: name: Unknown
Year: 1999
Subjects: subject: Research and Development/Tech Change/Emerging Technologies
subject: Gene banks
subject: Plant
subject: Biotechnology

description: The lack of ex-ante evaluation of germplasm in genebanks has been the single most prevalent and long-standing complaint of plant breeders about the management of genebanks. Advances in biotechnology offer the possibility of faster, cheaper, and more efficient evaluation methodologies. Will these new technologies favor ex-post evaluation, as some expect, or will it lead to more ex-ante evaluation? Will it also lead to earlier development of varieties with disease resistance traits in anticipation of actual infestations? Will the prospect of further advances in biotechnology favor delay of evaluation and development? This paper addresses these questions in the case of evaluation of germplasm for resistance to a disease.
Intense Diffuse Far-UV Emission from the Orion Nebula
Creators: name: Murthy, Jayant
name: Sahnow, David J.
name: Henry, R. C.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present spectra of the diffuse FUV (900 -- 1200 Å) emission from a region near the Orion Nebula: the first high resolution spectra of the diffuse background radiation. These observations were made using serendipitous FUSE observations and were only possible because of the strength of the diffuse emission (~3 x 10^5 photons cm-2 s-1 sr-1 A-1) and the sensitivity of the FUSE instrument. Preliminary modeling suggests that the light is scattered starlight from the Trapezium stars, primarily Theta Ori 1 C. However, a comparison of the spectra with nearby stars shows significant differences in the presence and strength of the absorption lines, particularly in the LyB line where there is much less interstellar absorption in our diffuse spectrum. We believe that we are indeed observing scattered light from the Trapezium stars but through a line of sight with much less matter than the direct line to the stars.
description: 10 pages, 4 figures, submitted to ApJL
Many-electron effects in the hyperfine splitting of lithiumlike ions
Creators: name: Kosheleva, V. P.
name: Volotka, A. V.
name: Glazov, D. A.
name: Fritzsche, S.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: The rigorous QED evaluation of the one- and two-photon exchange corrections to the ground-state hyperfine splitting in Li-like ions is presented for the wide range of nuclear charge number $Z= 7 - 82$. The calculations are carried out in the framework of the extended Furry picture, i.e., with inclusion of the effective local screening potential in the zeroth-order approximation. The interelectronic-interaction contributions of the third and higher orders are taken into account in the framework of the Breit approximation employing the recursive perturbation theory. In comparison to the previous theoretical calculations, the accuracy of the interelectronic-interaction contributions to the ground-state hyperfine splitting in Li-like ions is substantially improved.
The changing organizational basis of African agricultural research
Creators: name: Roseboom, Johannes
name: Pardey, Philip G.
name: Beintema, Nienke M.
name: Roseboom, Johannes
name: Pardey, Philip G.
name: Beintema, Nienke M.
Publisher: name: Unknown
Year: 1998
Subjects: subject: Research and Development/Tech Change/Emerging Technologies
subject: Research--Economic aspects
subject: Research institutes
subject: Africa
subject: Agriculture--Research

description: National agricultural research systems in Africa increased markedly in size throughout the past three decades, but from an especially small base. In 1961, public systems in 33 of 48 African countries employed fewer than 25 full-time equivalent (fte) researchers, by 1991 there were only 8 such systems (and 23 countries employed more than 100 fte researchers, compared with only 4 countries in 1961). Despite this overall growth, and the efforts that began in the late 1980s to consolidate the conduct of agricultural research, most African agencies are still very small and fragmented by international standards, making it difficult to realize the scale and scope economies that seem increasingly evident in agricultural R&D conducted elsewhere. This study reports a range of institutional indicators for 341 agricultural research agencies located in 39 African countries. In 1991, 236 agencies (nearly 70 percent of our sample total) employed less than 20 fte researchers. Most public research in Africa is still done by government agencies; they employed 87 percent of the total number of researchers in 1991. University research has grown the most rapidly, but still accounted for only 10 percent of the total number of African researchers in 1991. Partly in response to the small, fragmented, and comparatively isolated structure of agricultural R&D agencies, but partly from local political and, especially, donor pressure too, there has been a proliferation of research networks in recent years. We identified 86 networks, of which 72 involved Africans linked to Africans, a rather parochial strategy in an increasingly interdependent world. Regional approaches to the conduct and funding of agricultural R&D have been revived in more recent years, a feature of much of the region's research in earlier, colonial times, as we describe here. However, the political and economic realities of today bear little relationship to those of colonial times, and it remains unclear how these regional approaches will prosper and effect meaningful research given the organizational uncertainties that still abound.
description: "November 1998". Also published as ISNAR paper no. 98-17". Includes bibliographical references (p. 65-69).
Evolutionary Signatures in the Formation of Low-Mass Protostars
Creators: name: Young, Chadwick H.
name: Evans, Neal J.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present an evolutionary picture of a forming star. We assume a singular, isothermal sphere as the initial state of the core that undergoes collapse as described by \citet{shu77}. We include the evolution of a first hydrostatic core at early times and allow a disk to grow as predicted by \citet{adams86}. We use a 1-dimensional radiative transfer code to calculate the spectral energy distribution for the evolving protostar from the beginning of collapse to the point when all envelope material has accreted onto the star+disk system. Then, we calculate various observational signatures ($T_{bol}$, $L_{bol}/L_{smm}$, and infrared colors) as a function of time. As defined by the bolometric temperature criterion, the Class 0 stage should be very short, while the Class I stage persists for much of the protostar's early life. We present physical distinctions among the classes of forming stars and calculate the observational signatures for these classes. Finally, we present models of infrared color-magnitude diagrams, as observed by the Spitzer Space Telescope, that should be strong discriminators in determining the stage of evolution for a protostar.
description: accepted ApJ
Understorey-overstorey biotic and nutrient interactions are key factors for Pinus pinaster growth and development under oligotrophic conditions
Creators: name: Vidal, David F.
name: Augusto, Laurent
name: Bakker, Mark R.
name: Trichet, Pierre
name: Puzos, Luc
name: Domec, Jean-Christophe
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: Ecology
subject: FOS: Biological sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: Plant Biology

description: The main objective of this study was to examine the interactive effects of nutrient availability and understorey plants, including a nitrogen(N)-fixing shrub, on growth, physiology and survival of commercial maritime pines (Pinus pinaster Ait.). Three experimental sites within the Landes de Gascogne forest were installed in two wet moorlands (one dominated by gorse, a leguminous shrub and one by a perennial grass), and in one dry moorland dominated by ericaceous plants. In dry moorland, the ericaceous understorey increased pine mortality and decreased pine growth, suggesting a competition for water, the most limiting resource of this ecosystem. In wet moorland, a decrease in pine growth suggested a strong competition for soil resources, with or without phosphorus addition. In the other wet moorland dominated by gorse, pines responded to competition for light through stem elongation and self-pruning, but not by reducing growth. The intercropped gorse improved pine N-nutrition and trees acclimated to shrubs by growing more fine roots. Gorse had a positive effect on stomatal conductance during spring, while pine water status decreased moderately with increasing shrub competition during summer. Our results provide new understanding of the feasibility of using gorse as an intercropping N-fixing plant in managed forests, and revealed the structural and physiological trade-offs that exist between increasing N-availability and competition for water and light.
Role of inputs, institutions, and technical innovations in stimulating growth in Chinese agriculture
Creators: name: Fan, Shenggen
name: Pardey, Philip G.
name: Fan, Shenggen
name: Pardey, Philip G.
Publisher: name: Unknown
Year: 1995
Subjects: subject: International Development
subject: Research and Development/Tech Change/Emerging Technologies
subject: Growth economics -- Models
subject: Agricultural productivity -- China

description: Recent attempts to quantify the sources of growth in Chinese agriculture have attributed an exceptionally large share of this growth to the contemporary institutional and market reforms within China. To analyze this important issue we use a newly constructed panel data set that includes an agricultural research or stock-of-knowledge variable. Our results suggest that while still a significant source of growth, the direct growth promoting consequence of institutional change and market reforms have been overstated by these earlier studies, even during the early stages of reforms that included the rapid introduction of the household production responsibility system. Research-induced technical change accounts for nearly 20% of the growth in aggregate agricultural output since 1965 although the share of growth attributable to technological innovation and changes in inputs and institutions varies considerably over time. Disaggregating the results within China also reveals substantial interregional variability in the sources of local growth, as would be expected in such a large and diverse country.
description: Cover title. "September 1995"--Cover. Includes bibliographical references (p. 33-35).
The onset of a small-scale turbulent dynamo at low magnetic Prandtl numbers
Creators: name: Schekochihin, A. A.
name: Haugen, N. E. L.
name: Brandenburg, A.
name: Cowley, S. C.
name: Maron, J. L.
name: McWilliams, J. C.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We study numerically the dependence of the critical magnetic Reynolds number Rmc for the turbulent small-scale dynamo on the hydrodynamic Reynolds number Re. The turbulence is statistically homogeneous, isotropic, and mirror--symmetric. We are interested in the regime of low magnetic Prandtl number Pm=Rm/Re<1, which is relevant for stellar convective zones, protostellar disks, and laboratory liquid-metal experiments. The two asymptotic possibilities are Rmc->const as Re->infinity (a small-scale dynamo exists at low Pm) or Rmc/Re=Pmc->const as Re->infinity (no small-scale dynamo exists at low Pm). Results obtained in two independent sets of simulations of MHD turbulence using grid and spectral codes are brought together and found to be in quantitative agreement. We find that at currently accessible resolutions, Rmc grows with Re with no sign of approaching a constant limit. We reach the maximum values of Rmc~500 for Re~3000. By comparing simulations with Laplacian viscosity, fourth-, sixth-, and eighth-order hyperviscosity and Smagorinsky large-eddy viscosity, we find that Rmc is not sensitive to the particular form of the viscous cutoff. This work represents a significant extension of the studies previously published by Schekochihin et al. 2004, PRL 92, 054502 and Haugen et al. 2004, PRE, 70, 016308 and the first detailed scan of the numerically accessible part of the stability curve Rmc(Re).
description: 4 pages, emulateapj aastex, 2 figures; final version as published in ApJL (but with colour figures)
Recent $J/ψ$ Results from BESII
Creators: name: Shen, Xiaoyan
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The studies on the multi-quark candidates, light scalar mesons and excited baryon states at BES are presented, based on $5.8 \times 10^7$ $J/ψ$ data collected with BESII detector. The measurements of some $J/ψ$ and $η_c$ decays are presented too. We also report the searches for the lepton flavor violation and pentaquark states in $J/ψ$ decays.
description: Talk given at 10th International Symposium on Meson-Nucleon Physics and the Structure of the Nucleon (MENU 2004), Beijing, China, 29 Aug - 4 Sept. 2004, 6 pages, 8 figures, to be published in Int. J. Mod. Phys
Analytic Modelling of a Planar Goubau Line with Circular Conductor
Creators: name: Schaich, Tobias
name: Molnar, Daniel
name: Rawi, Anas Al
name: Payne, Mike
Publisher: name: arXiv
Year: 2020
Subjects: subject: Classical Physics (physics.class-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: This paper analyses the surface wave mode propagating along a simplified planar Goubau line consisting of a perfectly conducting circular wire on top of a dielectric substrate of finite thickness but infinite width. An approximate equation for the propagation constant is derived and solved through numerical integration. The dependence of the propagation constant on various system parameters is calculated and the results agree well with full numerical simulations. In addition, the spatial distribution of the longitudinal electric field is reported and excellent agreement with the numerical simulation and previous studies is found. Moreover, validation against experimental phase velocity measurements is also reported. Finally, insights gained from the model are considered for a Goubau line with a rectangular conductor. These results present the first step towards an analytic model of the planar Goubau line.
description: 15 pages, 4 figures Submitted To Nature Scientific Reports
Photonic band structure of ZnO photonic crystal slab laser
Creators: name: Yamilov, A.
name: Wu, X.
name: Cao, H.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We recently reported on the first realization of ultraviolet photonic crystal laser based on zinc oxide [Appl. Phys. Lett. {\bf 85}, 3657 (2004)]. Here we present the details of structural design and its optimization. We develop a computational super-cell technique, that allows a straightforward calculation of the photonic band structure of ZnO photonic crystal slab on sapphire substrate. We find that despite of small index contrast between the substrate and the photonic layer, the low order eigenmodes have predominantly transverse-electric (TE) or transverse-magnetic (TM) polarization. Because emission from ZnO thin film shows strong TE preference, we are able to limit our consideration to TE bands, spectrum of which can possess a complete photonic band gap with an appropriate choice of structure parameters. We demonstrate that the geometry of the system may be optimized so that a sizable band gap is achieved.
description: 8 pages, 7 figures
Hog Options: Contract Redesign and Market Efficiency
Creators: name: Urcola, Hernan A.
name: Irwin, Scott H.
name: Urcola, Hernan A.
name: Irwin, Scott H.
Publisher: name: Unknown
Year: 2010
Subjects: subject: Agribusiness
subject: Agricultural Finance
subject: Crop Production/Industries
subject: Demand and Price Analysis
subject: Farm Management
subject: Financial Economics
subject: Livestock Production/Industries
subject: Marketing
subject: FOS: Economics and business
subject: Production Economics
subject: Productivity Analysis
subject: Public Economics
subject: Research Methods/ Statistical Methods
subject: hog options
subject: mispricing perceptions
subject: contract redesign
subject: trading returns

description: This article tests the efficiency of the hog options market and assesses the impact of the 1996 contract redesign on efficiency. We find that the hog options market is efficient, but some options yielded excess returns during the live hogs period but not during the lean hogs period. Our findings indicate that the hog options market is efficient and is consistent with the new contract improving the efficiency of the market. However, other market conditions such as lower transaction costs during the lean hogs period can also contribute to reduce expected option returns during the latter period.
Preliminary data on cryoconservation of male gametes of the scallop Pecten maximu sfor experimental purposes and development of aquaculture
Creators: name: Micarelli, Primo
Publisher: name: figshare
Year: 2020
Subjects: subject: 70401 Aquaculture
subject: FOS: Agriculture, forestry and fisheries

description: The year round availability of high numbers of topquality bivalves larvae is a major problem in the field of molluscs farming. As regards monitoring of gonad ripening , recent technical developments have allowed the periods of natural spawning of male and female gametes to be extended, by manipulation of environmental parameters. Instead, as regards gamete and embryo stocking, available information is scanty and refer exclusively to cryopreservation for fish (Villani and Catena 1991) and mammals. The Ifremer Centre of Brest (France) has carried out some low-temperature preservation experiments of Pecten maximus male gametes over a period of three months, in order to evaluate their preservation in time and later use for fertilization tests.
Coupling a mobile hole to an antiferromagnetic spin background: Transient dynamics of a magnetic polaron
Creators: name: Ji, Geoffrey
name: Xu, Muqing
name: Kendrick, Lev Haldar
name: Chiu, Christie S.
name: Brüggenjürgen, Justus C.
name: Greif, Daniel
name: Bohrdt, Annabelle
name: Grusdt, Fabian
name: Demler, Eugene
name: Lebrat, Martin
name: Greiner, Markus
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Understanding the interplay between charge and spin and its effects on transport is a ubiquitous challenge in quantum many-body systems. In the Fermi-Hubbard model, this interplay is thought to give rise to magnetic polarons, whose dynamics may explain emergent properties of quantum materials such as high-temperature superconductivity. In this work, we use a cold-atom quantum simulator to directly observe the formation dynamics and subsequent spreading of individual magnetic polarons. Measuring the density- and spin-resolved evolution of a single hole in a 2D Hubbard insulator with short-range antiferromagnetic correlations reveals fast initial delocalization and a dressing of the spin background, indicating polaron formation. At long times, we find that dynamics are slowed down by the spin exchange time, and they are compatible with a polaronic model with strong density and spin coupling. Our work enables the study of out-of-equilibrium emergent phenomena in the Fermi-Hubbard model, one dopant at a time.
description: 7+11 pages, 5+8 figures
Studies of orbital parameters and pulse profile of the accreting millisecond pulsar XTE J1807-294
Creators: name: Kirsch, M. G. F.
name: Mukerjee, K.
name: Breitfellner, M. G.
name: Djavidnia, S.
name: Freyberg, M. J.
name: Kendziorra, E.
name: Smith, M. J. S.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The accreting millisecond pulsar XTE J1807-294 was observed by XMM-Newton on March 22, 2003 after its discovery on February 21, 2003 by RXTE. The source was detected in its bright phase with an observed average count rate of 33.3 cts/s in the EPIC-pn camera in the 0.5-10 keV energy band (3.7 mCrab). Using the earlier established best-fit orbital period of 40.0741+/-0.0005 minutes from RXTE observations and considering a circular binary orbit as first approximation, we derived a value of 4.8+/-0.1 lt-ms for the projected orbital radius of the binary system and an epoch of the orbital phase of MJD 52720.67415(16). The barycentric mean spin period of the pulsar was derived as 5.2459427+/-0.0000004 ms. The pulsar's spin-pulse profile showed a prominent (1.5 ms FWHM) pulse, with energy and orbital phase dependence in the amplitude and shape. The measured pulsed fraction in four energy bands was found to be 3.1+/-0.2 % (0.5-3.0 keV), 5.4+/-0.4 % (3.0-6.0 keV), 5.1+/-0.7 % (6.0-10.0 keV) and 3.7+/-0.2 % (0.5-10.0 keV), respectively. Studies of spin-profiles with orbital phase and energy showed significant increase in its pulsed fraction during the second observed orbit of the neutron star, gradually declining in the subsequent two orbits, which was associated with sudden but marginal increase in mass accretion. From our investigations of orbital parameters and estimation of other properties of this compact binary system, we conclude that XTE J1807-294 is very likely a candidate for a millisecond radio pulsar.
description: 4 pages, 4 figures, Accepted for publication in Astronomy and Astrophysics letters
Do Farmers Hedge Optimally or by Habit? A Bayesian Partial-Adjustment Model of Farmer Hedging
Creators: name: Dorfman, Jeffrey H.
name: Karali, Berna
name: Dorfman, Jeffrey H.
name: Karali, Berna
Publisher: name: Unknown
Year: 2010
Subjects: subject: Agribusiness
subject: Agricultural Finance
subject: Farm Management
subject: Financial Economics
subject: Labor and Human Capital
subject: Production Economics
subject: Productivity Analysis
subject: Research Methods/ Statistical Methods
subject: Bayesian econometrics
subject: habit formation
subject: hedging decisions
subject: information sources

description: Hedging is one of the most important risk management decisions that farmers make and has a potentially large role in the level of profit eventually earned from farming. Using panel data from a survey of Georgia farmers that recorded their hedging decisions for 4 years on four crops, we examine the role of habit, demographics, farm characteristics, and information sources on the hedging decisions made by 57 different farmers. We find that the role of habit varies widely and that estimation of a single habit effect suffers from aggregation bias. Thus, modeling farmer-level heterogeneity in the examination of habit and hedging is crucial.
Dynamic Effects of Grain and Energy Prices on the Catfish Feed and Farm Sectors
Creators: name: Muhammad, Andrew
name: Zheng, Hualu
name: Muhammad, Andrew
name: Zheng, Hualu
Publisher: name: Unknown
Year: 2010
Subjects: subject: Agribusiness
subject: Agricultural Finance
subject: Demand and Price Analysis
subject: Financial Economics
subject: Institutional and Behavioral Economics
subject: Marketing
subject: FOS: Economics and business
subject: Production Economics
subject: Productivity Analysis
subject: Resource /Energy Economics and Policy
subject: catfish
subject: prices
subject: autoregressive distributed lag (ARDL) model
subject: ethanol
subject: feed
subject: corn
subject: soybeans

description: This study examines the dynamic effects of grain prices and energy prices on catfish feed prices and the price of food-sized catfish at the farm level. Using the autoregressive distributed lag model and bounds testing procedure, a long-run relationship between feed and farm prices and their determinants was confirmed. Given the effect of corn and soybean meal prices on catfish feed prices, and catfish fish feed prices on farm prices, the long-run responsiveness of feed prices to a percentage increase in U.S. ethanol production is 0.325, and the responsiveness of catfish farm prices is 0.064. Although both feed and farm prices increase with ethanol production, the relatively small responsiveness of farm prices when compared with feed prices suggests that catfish farmers are worse off. Results are conditional on ethanol production causing an increase in grain prices.
Stability of Landau-Ginzburg branes
Creators: name: Walcher, Johannes
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Algebraic Geometry (math.AG)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We evaluate the ideas of Pi-stability at the Landau-Ginzburg point in moduli space of compact Calabi-Yau manifolds, using matrix factorizations to B-model the topological D-brane category. The standard requirement of unitarity at the IR fixed point is argued to lead to a notion of "R-stability" for matrix factorizations of quasi-homogeneous LG potentials. The D0-brane on the quintic at the Landau-Ginzburg point is not obviously unstable. Aiming to relate R-stability to a moduli space problem, we then study the action of the gauge group of similarity transformations on matrix factorizations. We define a naive moment map-like flow on the gauge orbits and use it to study boundary flows in several examples. Gauge transformations of non-zero degree play an interesting role for brane-antibrane annihilation. We also give a careful exposition of the grading of the Landau-Ginzburg category of B-branes, and prove an index theorem for matrix factorizations.
description: 46 pages, LaTeX, summary added
An Improved Method for Calibrating Purchase Intentions in Stated Preference Demand Models
Creators: name: Davies, Stephen P.
name: Loomis, John B.
name: Davies, Stephen P.
name: Loomis, John B.
Publisher: name: Unknown
Year: 2010
Subjects: subject: Agribusiness
subject: Agricultural Finance
subject: Consumer/Household Economics
subject: Demand and Price Analysis
subject: Financial Economics
subject: Food Consumption/Nutrition/Food Safety
subject: Institutional and Behavioral Economics
subject: Marketing
subject: FOS: Economics and business
subject: Production Economics
subject: Productivity Analysis
subject: Research Methods/ Statistical Methods
subject: hypothetical bias
subject: Orbit
subject: ordered probit model
subject: travel cost model
subject: recreation
subject: stated preference

description: The Orbit demand model allows the magnitude of the calibration to stated purchase intentions to vary based on the magnitude of the stated quantities. Using an empirical example of stated trips, we find that the extent of calibration varies substantially with less correction needed at small stated trips (–25%) but larger corrections at higher quantities of stated visits (–48%). We extend the Orbit model to calculate consumer surplus per stated trip of $26. Combining the calibrations in stated trips and value per trip, the Orbit model provides estimates of annual benefits from 60% to 111% less than the count data model.
Preliminary histological observations of mature gonads in Pecten jacobaeus fished off western Sardinia Item
Creators: name: Micarelli, Primo
name: Ceccarelli, Riccardo
name: Bitetto, Massimiliano Di
Publisher: name: figshare
Year: 2020
Subjects: subject: 70401 Aquaculture
subject: FOS: Agriculture, forestry and fisheries

description: In Italy, the studies on Pecten jacobaeus are limited to natural populations present in Adriatic Sea, because of widespread and commercial interest of this species. Brief information on this species, with particular emphasis on diffusion and fishing techniques, are reported by Renzoni (1991). The studies on on its biology and reproductive physiology are limited to the Adriatic area (Valli 1977, 1979). The present study aims to increase current knowledge on the reproductive biology of P.jacobaeus, in the Tyrrhenian sea, looking also the possible aquaculture development of this resource.
Single- and double-vortex vector solitons in self-focusing nonlinear media
Creators: name: Salgueiro, Jose R.
name: Kivshar, Yuri S.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences

description: We study two-component spatial optical solitons carrying an angular momentum and propagating in a self-focusing saturable nonlinear medium. When one of the components is small, such vector solitons can be viewed as a self-trapped vortex beam that guides either the fundamental or first-order guided mode, and they are classified as single- and double-vortex vector solitons. For such composite vortex beams, we demonstrate that a large-amplitude guided mode can stabilize the ring-like vortex beam which usually decays due to azimuthal modulational instability. We identify different types of these vector vortex solitons and demonstrate both vortex bistability and mutual stabilization effect.
description: 7 pages, 13 figures
FREIGHT VILLAGES: MODERN  WAREHOUSE DESIGN AND RAIL LINK ASPECTS
Creators: name: Nazirov, Nozimjon
name: Tashmurodov, Umidjon
Publisher: name: Zenodo
Year: 2024

description: Freight villages reflect a modern way of organizing logistics, transport and goods distribution activities. Warehouses are a basic element in such building complexes and their efficient planning and operation is essential for the viability of the system. Warehouse design requires a mixture of analytical skills and creativity. Although effort has been dedicated to define a global methodological design framework, the overwhelming majority of scientific papers on the subject address well-defined isolated problems. On the other hand, a practitioner may notice that a great number of warehouses offering efficient, cost-effective services are in operation nowadays and that a number of warehouse design manuals, tackling actual design and operation aspects exist.
Analysis of Import Demand for Wooden Beds in the U.S.
Creators: name: Wan, Yang
name: Sun, Changyou
name: Grebner, Donald L.
name: Wan, Yang
name: Sun, Changyou
name: Grebner, Donald L.
Publisher: name: Unknown
Year: 2010
Subjects: subject: Agribusiness
subject: Consumer/Household Economics
subject: Demand and Price Analysis
subject: Financial Economics
subject: Marketing
subject: FOS: Economics and business
subject: antidumping
subject: cointegration
subject: demand elasticity
subject: furniture
subject: trade diversion

description: The market of wooden beds in the U.S. has been flooded with imports from China and Vietnam in recent years. Static and dynamic Almost Ideal Demand System models are used to assess the import demand for wooden beds from the top seven supplying countries. The analyses reveal that the antidumping investigation on China has some temporary trade depression effect on China, but trade diversion occur to Vietnam, Indonesia, Canada, and Brazil. The formal implementation of antidumping duties since 2005 has not shown any significant effect on the trade pattern. U.S. consumers spend more on beds from newly industrialized countries and there are moderate degrees of substitution among wooden beds from most countries.
Study from nature : women, mobility, and the politics of urban vision in Harper’s Weekly, January 1860
Creators: name: Steinmann, Catherine A.
Publisher: name: University of British Columbia
Year: 2009

description: Nestled among the classified ads on the back page of the January 21, 1860, issue of Harper's Weekly is a cartoon that marks a moment of anxiety in the public life of the New York middle class on the eve of the Civil War. Set in the increasingly illegible streets of the rapidly changing city, this fragmented lithograph represents, in two frames, four women—two white, one black, one unidentifiable—walking on a pavement during and after the passing of an omnibus. Harper's published the image, titled Study from Nature, in a moment when issues of citizenship, civic capacity, and national belonging were rapidly coming to the forefront of public consciousness, especially in New York, which was a nexus for feminist, abolitionist, and black manhood suffrage movements. The pages Study from Nature sits among are spatially analogous to the physical environment of the street. Similarly, the image mimics the spatial experience of a viewer standing in that street, at once describing and formally manifesting the visual change that was at the core of riew challenges to urban legibility. In this respect, the image serves both as a guide for the viewer and as a visual puzzle that re-presented to that viewer many of the changes in vision that inhabitants of the city were experiencing—changes that occurred alongside the rise of industrial commercialism, increasing urban density, and developments in fashion, architecture, and systems of urban transport. I argue that Study from Nature participated in a set of regulatory discourses that produced and responded to concerns over the visual metamorphosis of free black and bourgeois white women, their increasing freedom to move about in metropolitan space, and their mounting resistance to ideologies that denied them subjective personhood. Emphasizing civility and sartorial self-discipline, Study from Nature attempted to order the intractable bodies circulating within it, creating a comic, admonitory fantasy of fear and subjugation. Through satire, the cartoon imposed punishment for acts that transgressed performative standards of race and gender, thereby depoliticizing social relations and deflecting the conflicts and inequities of New York society onto the individual inhabitants of the street.
SUSY-Breaking Scenarios With a Mildly Violated R Symmetry
Creators: name: Pallis, C.
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: New realizations of the gravity-mediated SUSY breaking are presented consistently with an R symmetry. We employ monomial superpotential terms for the hidden-sector (goldstino) superfield and Kahler potentials parameterizing compact or non-compact Kahler manifolds. Their scalar curvature may be systematically related to the R charge of the goldstino so that Minkowski solutions without fine tuning are achieved. A mild violation of the R symmetry by a higher order term in the Kahler potentials allows for phenomenologically acceptable masses for the R axion. In all cases, non-vanishing soft SUSY-breaking parameters are obtained and a solution to the mu problem of MSSM may be accommodated by conveniently applying the Giudice-Masiero mechanism.
description: Revised version accepted for publication in EPJC
Detection of Thermal Emission from an Extrasolar Planet
Creators: name: Charbonneau, David
name: Allen, Lori E.
name: Megeath, S. Thomas
name: Torres, Guillermo
name: Alonso, Roi
name: Brown, Timothy M.
name: Gilliland, Ronald L.
name: Latham, David W.
name: Mandushev, Georgi
name: O'Donovan, Francis T.
name: Sozzetti, Alessandro
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present Spitzer Space Telescope infrared photometric time series of the transiting extrasolar planet system TrES-1. The data span a predicted time of secondary eclipse, corresponding to the passage of the planet behind the star. In both bands of our observations, we detect a flux decrement with a timing, amplitude, and duration as predicted by published parameters of the system. This signal represents the first direct detection of (i.e. the observation of photons emitted by) a planet orbiting another star. The observed eclipse depths (in units of relative flux) are 0.00066 +/- 0.00013 at 4.5um and 0.00225 +/- 0.00036 at 8.0um. These estimates provide the first observational constraints on models of the thermal emission of hot Jupiters. Assuming that the planet emits as a blackbody, we estimate an effective temperature of T_p=1060 +/- 50 K. Under the additional assumptions that the planet is in thermal equilibrium with the radiation from the star and emits isotropically, we find a Bond albedo of A = 0.31 +/- 0.14. This would imply that the planet absorbs the majority of stellar radiation incident upon it, a conclusion of significant impact to atmospheric models of these objects. We compare our data to a previously-published model of the planetary thermal emission, which predicts prominent spectral features in our observational bands due to water and carbon monoxide. Based on the time of secondary eclipse, we present an upper limit on the orbital eccentricity that is sufficiently small that we conclude that tidal dissipation is unlikely to provide a significant source of energy interior to the planet.(abridged)
description: 20 pages, 4 figures, to appear in the Astrophysical Journal, 20 June 2005
Uncertainties of Sudakov form factors
Creators: name: Gieseke, Stefan
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the uncertainties of Sudakov form factors as the basis for parton shower evolution in Monte Carlo event generators. We discuss the particular cases of systematic uncertainties of parton distribution functions and scale uncertainties.
description: 17 pages, 10 Figures