cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Improving stability of moving particle semi-implicit method by source terms based on time-scale correction of particle-level impulses
Creators: name: Cheng, Liang-Yee
name: Junior, Rubens Augusto Amaro
name: Favero, Eric Henrique
Publisher: name: arXiv
Year: 2022
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: The aim of this paper is to investigate the unstable nature of pressure computation focusing on incompressible flow modeling through the projection-based particle methods. A new approach from the original viewpoint of the momentum conservation regarding particle-level collisions, hereinafter refered to as time-scale correction of particle-level impulses (TCPI), is proposed to derive new source terms of pressure Poisson equation (PPE). This results in more stable computations with drastic reduction of unphysical pressure oscillations and more robust simulation with pressure magnitudes almost independent to time step. Moreover, compared to other strategies, no additional computational effort is required, its implementation is extremely simple, and the only numerical parameter is the propagation speed of the perturbations, of which the calibration is much more straightforward due to its physical meaning. Simulations were carried out using moving particle semi-implicit (MPS) method improved by the proposed approach. The comparisons of computed results with theoretical and experimental ones confirmed the effectiveness of the proposed approach.
description: 70 Pages, 35 Figures
Standard Errors for Nonparametric Regression
Creators: name: Chu, Ba M.
name: Jacho-Chávez, David T.
name: Linton, Oliver B.
Publisher: name: Taylor & Francis
Year: 2020
Subjects: subject: Medicine
subject: Genetics
subject: FOS: Biological sciences
subject: Molecular Biology
subject: Neuroscience
subject: Biotechnology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 19999 Mathematical Sciences not elsewhere classified
subject: FOS: Mathematics
subject: Marine Biology
subject: 111714 Mental Health
subject: FOS: Health sciences
subject: Plant Biology

description: This paper proposes five pointwise consistent and asymptotic normal estimators of the asymptotic variance function of the Nadaraya-Watson kernel estimator for nonparametric regression. The proposed estimators are constructed based on the first-stage nonparametric residuals, and their asymptotic properties are established under the assumption that the same bandwidth sequences are used throughout, which mimics what researchers do in practice while making derivations more complicated instead. A limited Monte Carlo experiment demonstrates that the proposed estimators possess smaller pointwise variability in small samples than the pair and wild bootstrap estimators which are commonly used in practice.
GALÆXI: Solving complex compressible flows with high-order discontinuous Galerkin methods on accelerator-based systems
Creators: name: Kempf, Daniel
name: Kurz, Marius
name: Blind, Marcel
name: Kopper, Patrick
name: Offenhäuser, Philipp
name: Schwarz, Anna
name: Starr, Spencer
name: Keim, Jens
name: Beck, Andrea
Publisher: name: arXiv
Year: 2024
Subjects: subject: Mathematical Software (cs.MS)
subject: Computational Engineering, Finance, and Science (cs.CE)
subject: FOS: Computer and information sciences

description: This work presents GALAEXI as a novel, energy-efficient flow solver for the simulation of compressible flows on unstructured meshes leveraging the parallel computing power of modern Graphics Processing Units (GPUs). GALAEXI implements the high-order Discontinuous Galerkin Spectral Element Method (DGSEM) using shock capturing with a finite-volume subcell approach to ensure the stability of the high-order scheme near shocks. This work provides details on the general code design, the parallelization strategy, and the implementation approach for the compute kernels with a focus on the element local mappings between volume and surface data due to the unstructured mesh. GALAEXI exhibits excellent strong scaling properties up to 1024 GPUs if each GPU is assigned a minimum of one million degrees of freedom degrees of freedom. To verify its implementation, a convergence study is performed that recovers the theoretical order of convergence of the implemented numerical schemes. Moreover, the solver is validated using both the incompressible and compressible formulation of the Taylor-Green-Vortex at a Mach number of 0.1 and 1.25, respectively. A mesh convergence study shows that the results converge to the high-fidelity reference solution and that the results match the original CPU implementation. Finally, GALAEXI is applied to a large-scale wall-resolved large eddy simulation of a linear cascade of the NASA Rotor 37. Here, the supersonic region and shocks at the leading edge are captured accurately and robustly by the implemented shock-capturing approach. It is demonstrated that GALAEXI requires less than half of the energy to carry out this simulation in comparison to the reference CPU implementation. This renders GALAEXI as a potent tool for accurate and efficient simulations of compressible flows in the realm of exascale computing and the associated new HPC architectures.
description: 19 pages, 12 figures, 3 tables. Accepted Manuscript. Code available at: https://github.com/flexi-framework/galaexi
Galley Congress Inspection Report (Legacy 01-162)
Creators: name: Cohn, Arthur
Publisher: name: DoD Legacy Resource Management Program
Year: 2001
Subjects: subject: Vermont
valueUri: https://core.tdar.org/browse/geographic-keyword/80813/vermont
subject: Arnold's Bay
valueUri: https://core.tdar.org/browse/geographic-keyword/85504/arnolds-bay
subject: Lake Champlain
valueUri: https://core.tdar.org/browse/geographic-keyword/35028/lake-champlain
subject: 18th Century
valueUri: https://core.tdar.org/browse/temporal-keyword/5549/18th-century
subject: American Revolutionary War
valueUri: https://core.tdar.org/browse/temporal-keyword/7782/american-revolutionary-war
subject: Historic
valueUri: https://core.tdar.org/browse/culture-keyword/25/historic
subject: Water-Related
valueUri: https://core.tdar.org/browse/site-type/365/water-related
subject: Shipwreck
valueUri: https://core.tdar.org/browse/site-type/367/shipwreck
subject: Archaeological Feature
valueUri: https://core.tdar.org/browse/site-type/339/archaeological-feature
subject: Documentation
valueUri: https://core.tdar.org/browse/other-keyword/26545/documentation
subject: Galley Congress
valueUri: https://core.tdar.org/browse/other-keyword/166484/galley-congress
subject: Mapping
valueUri: https://core.tdar.org/browse/other-keyword/19875/mapping
subject: General Benedict Arnold
valueUri: https://core.tdar.org/browse/other-keyword/166481/general-benedict-arnold
subject: Shipwreck
valueUri: https://core.tdar.org/browse/other-keyword/137042/shipwreck
subject: Underwater Archaeology
valueUri: https://core.tdar.org/browse/other-keyword/4198/underwater-archaeology
subject: Arnold's Bay
valueUri: https://core.tdar.org/browse/other-keyword/166485/arnolds-bay
subject: Archaeological Investigation
valueUri: https://core.tdar.org/browse/other-keyword/46172/archaeological-investigation
subject: Reconnaissance / Survey
valueUri: https://core.tdar.org/browse/investigation-type/7/reconnaissance-survey

description: The galley Congress was one of five vessels burned in Arnold Bay, Panton, Vermont, in 1776 by Benedict Arnold to prevent their capture by the British. This report of a 2001 inspection of the remains of the Congress discusses the documentation and measurement of scattered parts of the boat and records observations regarding the stability of the site, including the presence of zebra mussels.
Economic Perspectives of the Diversity of Risks among Crop Farmers in the Northern Guinea Savanna of Nigeria
Creators: name: Olarinde, Luke O.
name: Manyong, Victor M.
name: Akintola, J.O.
name: Olarinde, Luke O.
name: Manyong, Victor M.
name: Akintola, J.O.
Publisher: name: Unknown
Year: 2010
Subjects: Risk and Uncertainty

description: In this paper, we examine the diversity of risks that affect farming in the Northern Guinea Savanna of Nigeria. We also investigate the perspectives of these risks in relation to their economic implications on the farming enterprises. We also show that through reorganization of these risks, some derived factors have the ability to present themselves whether as corresponding to existing categorization of the variables or not and also to enable us know which of the factors is more important than the other. Gross margin and factor analytical methods were used in computing the estimated results on a cross sectional sample of 348 farming households. Results show that farmers who were grouped under natural risk incurred the least mean production cost of N11, 115.61, while the highest mean production cost of N 15,998.18 was incurred by farmers grouped under production risks. The highest mean revenue of N18, 998.16 was recorded by farmers under production risk which translated into a mean gross margin of N65, 999.85. Verifying whether some derived factors would correspond to the existing categorization of 14 risk types (from 5 sources) which the farmers faced, results from the factor analysis and the consequent F-tests from ANOVA show no marked or significant differences among the identified factors and the existing risk sources. Consequently, the individual effect or importance of the original 14 risk types that the sampled farmers considered important can be dully represented and effectively regrouped into five sources (factors) as natural, technical, social, ecosocial and biochemical.
The polarization of mm methanol masers
Creators: name: Wiesemeyer, Helmut
name: Thum, Clemens
name: Walmsley, Malcolm
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present a survey of the polarization properties of mm-wavelength methanol masers, comprising both classes, and transitions from 84.5 to 157.0 GHz. Linear polarization is found in more than half of the observed objects, and circular polarization is tentatively detected in two sources. Class I and Class II CH_3OH masers show similar polarization properties.The largest linear polarization is found in the 133 GHz Class I maser towards L379 (39.5 %), and in the 157 GHz Class II maser towards G9.62+0.19 (36.7 %). The spectral profiles of the polarization angle of Class I masers are mostly flat, except for two sources showing a linear slope. Since the mm-line methanol masers are expected to be weakly (or not) saturated, we suggest that the stronger fractional polarizations found by us are enhanced by anisotropic pumping and radiative losses. In NGC 7538, we find, for both maser classes, a good agreement between our polarization angles, and those measured for the submillimeter dust continuum. This can be taken as evidence for magnetic alignment of dust grains. It is also possible that an unsaturated maser with equally populated magnetic substates simply amplifies polarized continuum seed radiation. For Class II masers, the polarization properties of the various velocity components towards a given source with detectable polarization are quite homogeneous. A possible explanation is discussed. Since methanol is non-paramagnetic, the circular polarization of the unsaturated maser emission can only be due to variations of the angle between the magnetic field and the line of sight along the maser propagation path.
description: Astronomy & Astrophysics, in press, received 27 February 2004, accepted 27 July 2004
Penetration depth and gap structure in the antiperovskite oxide superconductor Sr$_{3-x}$SnO revealed by $μ$SR
Creators: name: Ikeda, Atsutoshi
name: Guguchia, Zurab
name: Oudah, Mohamed
name: Koibuchi, Shun
name: Yonezawa, Shingo
name: Das, Debarchan
name: Shiroka, Toni
name: Luetkens, Hubertus
name: Maeno, Yoshiteru
Publisher: name: arXiv
Year: 2020
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We report a $μ$SR study on the antiperovskite oxide superconductor Sr$_{3-x}$SnO. With transverse-field $μ$SR, we observed the increase of the muon relaxation rate upon cooling below the superconducting transition temperature $T_{\mathrm{c}}=5.4$ K, evidencing bulk superconductivity. The exponential temperature dependence of the relaxation rate $σ$ at low temperatures suggests a fully gapped superconducting state. We evaluated the zero-temperature penetration depth $λ(0)\propto1/\sqrt{σ(0)}$ to be around 320-1020 nm. Such a large value is consistent with the picture of a doped Dirac semimetal. Moreover, we revealed that the ratio $T_{\mathrm{c}}/λ(0)^{-2}$ is larger than those of ordinary superconductors and is comparable to those of unconventional superconductors. The relatively high $T_{\mathrm{c}}$ for small carrier density may hint at an unconventional pairing mechanism beyond the ordinary phonon-mediated pairing. In addition, zero-field $μ$SR did not provide evidence of broken time-reversal symmetry in the superconducting state. These features are consistent with the theoretically proposed topological superconducting state in Sr$_{3-x}$SnO, as well as with $s$-wave superconductivity.
description: 9 pages, 9 figures, to be published in Physical Review B
Delay compensated fade prediction based CDMA closed loop power control
Creators: name: Lee, Peter Ming Wong
Publisher: name: University of British Columbia
Year: 2009

description: Power control is essential in Code Division Multiple Access (CDMA) systems in order to reduce the near-far effect, optimize,the system capacity, and combat the signal degradation due to fading. One problem with Closed Loop Power Control (CLPC) is the delay introduced by power measurement and round-trip delay in the power control loop. We study the impact of power control loop delays on Frame Error Rate (FER) performance under a range of channel conditions. A new CLPC algorithm with delay compensation and fade prediction is then proposed to mitigate the effects of loop delays on CLPC. Delay compensation can reduce power oscillation amplitude around the desired received power level and fade prediction can forecast an upcoming fade in order to mitigate its effect. The FER performance on the forward link of an Interim Standard - 2000 (IS-2000) CDMA system using the delay compensated fade prediction based CLPC algorithm is studied. Simulations with a detailed IS-2000 physical layer model and various Third Generation Partnership Project 2 (3GPP2) channel models are used to illustrate the performance gains of the proposed CLPC algorithm over the conventional CLPC algorithm. The performance of the proposed CLPC algorithm as a function of mobile speed, delay, and carrier frequency is analyzed. It is found that the proposed CLPC algorithm performs better than the conventional CLPC algorithm by about 1 dB for a range of mobile speeds of interest. The performance improvement obtainable by using the proposed CLPC algorithm can reduce the interference and result in an increase in the system capacity. Finally, the effect of power control bit (PCB) errors on the performance of the proposed CLPC algorithm is studied. Simulation results indicate that the proposed CLPC algorithm is still beneficial when the PCB error rate is 5%.
Gauged Gaussian PEPS -- A High Dimensional Tensor Network Formulation for Lattice Gauge Theories
Creators: name: Kelman, Ariel
name: Borla, Umberto
name: Gomelski, Itay
name: Elyovich, Jonathan
name: Roose, Gertian
name: Emonts, Patrick
name: Zohar, Erez
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Gauge theories form the basis of our understanding of modern physics - ranging from the description of quarks and gluons to effective models in condensed matter physics. In the non-perturbative regime, gauge theories are conventionally treated discretely as lattice gauge theories. The resulting systems are evaluated with path-integral based Monte Carlo methods. These methods, however, can suffer from the sign problem and do not allow for a direct evaluation of real-time dynamics. In this work, we present a unified and comprehensive framework for gauged Gaussian Projected Entangled Pair States (PEPS), a variational ansatz based on tensor networks. We review the construction of Hamiltonian lattice gauge theories, explain their similarities with PEPS, and detail the construction of the state. The estimation of ground states is based on a variational Monte Carlo procedure with the PEPS as an ansatz state. This sign-problem-free ansatz can be efficiently evaluated in any dimension with arbitrary gauge groups, and can include dynamical fermionic matter, suggesting new options for the simulation of non-perturbative regimes of gauge theories, including QCD.
description: V2: update to match published version
Conservation Agriculture Practices and Adoption by Smallholder Farmers in Zimbabwe
Creators: name: Mazvimavi, Kizito
name: Ndlovu, Patrick V.
name: Nyathi, Putso
name: Minde, Isaac J.
name: Mazvimavi, Kizito
name: Ndlovu, Patrick V.
name: Nyathi, Putso
name: Minde, Isaac J.
Publisher: name: Unknown
Year: 2010
Subjects: subject: Farm Management
subject: Research and Development/Tech Change/Emerging Technologies
subject: Resource /Energy Economics and Policy
subject: conservation agriculture
subject: planting basins
subject: yield gains
subject: adoption labor
subject: and fertilizer

description: This study is based on a panel survey interviewing 416 farmers practising conservation agriculture for at least five cropping seasons. Farmers obtained higher yields on conservation agriculture plots than on nonconservation agriculture ones. The mean maize yield on conservation agriculture was 1546 kg/ha compared to 970 kg/ha for non-conventional draft tillage plots across all 15 districts. However, the contribution of conservation agriculture to total household food security requirements was limited due to small plot sizes. Labor and land still remains a major challenge that limits the expansion of conservation agriculture area. Winter weeding remains a challenge, with 63% of farmers practicing it. Application of residues is still limited (56% of farmers practising it). Fertilizer application is largely dependent on access to free fertilizer. The survey results show that the 78 % of the respondent farmers were initially selected by the NGOs and were provided with inputs such as seed and fertilizer. The other 22% of the farmers in the sample were selected as spontaneous adopters, who did not initially receive any NGO support to implement conservation agriculture practices. Eleven percent of the interviewed farmers had stopped conservation agriculture practices by the 2008/09 cropping season due to withdrawal of input support by NGOs. Research should continue to explore different recommendations for different areas as farmers face dynamic agro-ecological and soil environments. Conservation agriculture should not be introduced as a blanket technology for all areas, but should be flexible and adaptable to local conditions.
Déterminants de l’achat des semences améliorées de cultures maraîchères dans les structures formelles
Creators: name: Tchuinte, Ghislaine Simeni
name: Coulibaly, Ousmane
name: Biaou, Gauthier
name: Tchuinte, Ghislaine Simeni
name: Coulibaly, Ousmane
name: Biaou, Gauthier
Publisher: name: Unknown
Year: 2010
Subjects: subject: Farm Management
subject: semences
subject: cultures maraîchères
subject: systèmes semenciers maraîchers
subject: Bénin

description: Contrairement aux cultures de rente et vivrières pour lesquelles l’Etat a mis en place un minimum de politique, des moyens de production et de distribution de semences améliorées, les cultures maraîchères n’ont pas bénéficié d’un appui substantiel sur ce plan. L’objectif de cette étude est d’identifier et de caractériser les acteurs du système semencier des cultures maraîchères au Bénin, de déterminer les facteurs qui affectent la demande des producteurs en semences améliorées dans les structures formelles. Les données ont été collectées auprès de 284 producteurs répartis dans trois communes : Cotonou et Grand-Popo (Sud et Sud-ouest), Malanville au Nord-Est. Les résultats obtenus à l’aide de la revue de littérature, de la statistique descriptive et d’une régression multiple destinée à identifier les facteurs influençant l’achat des semences dans les structures formelles montrent que deux principales catégories d’acteurs sont impliquées dans le commerce des semences améliorées des cultures maraîchères : le secteur privé et le secteur public. Le secteur privé est représenté par les fournisseurs et est spécialisé dans la commercialisation, le stockage et la distribution ; l’Etat s’occupe du contrôle. Les facteurs qui influencent l’achat de semences améliorées dans les structures formelles sont : les prix identiques de vente dans les structures formelles et chez les distributeurs informels, la disponibilité des distributeurs informels, les perceptions des producteurs sur la distance séparant leurs sites de production des points de vente et les prix bas de vente de produits.
Application de la Programmation Stochastique Discrète à l’évaluation de l’impact de la contrainte de crédit sur le revenu et la production agricoles dans la basse vallée de l’Ouémé
Creators: name: Kpadonou, Rivaldo A.B.
name: Adegbola, Patrice Ygue
name: Tovignan, Silvere D.
name: Kpadonou, Rivaldo A.B.
name: Adegbola, Patrice Ygue
name: Tovignan, Silvere D.
Publisher: name: Unknown
Year: 2010
Subjects: subject: Agricultural Finance
subject: Programmation linéaire
subject: modélisation
subject: production
subject: revenu agricole
subject: Bénin

description: Malgré la mise en oeuvre des différentes politiques d’ajustement structurels découlant de l’option du libéralisme économique, l’économie béninoise peine toujours à décoller avec une agriculture à dominance familiale et traditionnelle, subvenant difficilement aux besoins des populations sans cesse croissantes. Les ménages agricoles ruraux vivent toujours dans des situations contraignantes de crédit qui sont souvent considérées comme faisant partie des contraintes majeures au développement agricole du pays. Ainsi, au regard de l’importance accordée au crédit dans les programmes de développement, cette étude s’est proposée d’analyser la vulnérabilité des exploitations agricole à la contrainte de crédit d’une part et, d’autre part, de faire une évaluation ex anté l’impact de la levée de cette contrainte sur la production et le revenu agricole de ces exploitations. L’étude a été réalisée dans la basse vallée de l’Ouémé et a utilisé les données empiriques collectées auprès de 54 exploitations agricoles. Ces données ont été complétées par les données secondaires de sources diverses. L’approche méthodologique adoptée a été la modélisation par la programmation linéaire stochastique discrète tenant compte des risques d’inondations. Le modèle de programmation élaboré a montré que les petites exploitations sont les plus vulnérables à la contrainte de crédit. Ainsi, le modèle a estimé respectivement à 2,62 ; 0,76 et 0,55 FCFA l’augmentation du revenu qui résulterait de l’apport d’un francs CFA supplémentaire du crédit formel pour les petites, moyennes et grandes exploitations. En ce qui concerne l’impact de la levée de la contrainte sur la production et le revenu agricoles, les prédictions du modèle ont montré que cette levée pourrait permettre d’accroître la production du piment de 66% tout en réduisant celle du niébé de 65%. Par ailleurs, l’impact de la levée de la contrainte de crédit sur le revenu agricole a été évalué à 21,26% pour les exploitations moyennes.
The Penobscot Expedition Archaeological Project: Field Investigations 2000 and 2001 - Report (Legacy 01-133)
Creators: name: Hunter, James
Publisher: name: DoD Legacy Resource Management Program
Year: 2003
Subjects: subject: Maine
valueUri: https://core.tdar.org/browse/geographic-keyword/46205/maine
subject: Penobscot River
valueUri: https://core.tdar.org/browse/geographic-keyword/26193/penobscot-river
subject: 18th Century
valueUri: https://core.tdar.org/browse/temporal-keyword/5549/18th-century
subject: American Revolutionary War
valueUri: https://core.tdar.org/browse/temporal-keyword/7782/american-revolutionary-war
subject: Historic
valueUri: https://core.tdar.org/browse/culture-keyword/25/historic
subject: Water-Related
valueUri: https://core.tdar.org/browse/site-type/365/water-related
subject: Shipwreck
valueUri: https://core.tdar.org/browse/site-type/367/shipwreck
subject: Archaeological Feature
valueUri: https://core.tdar.org/browse/site-type/339/archaeological-feature
subject: Wood
valueUri: https://core.tdar.org/browse/material-type/15/wood
subject: Ceramic
valueUri: https://core.tdar.org/browse/material-type/1/ceramic
subject: Glass
valueUri: https://core.tdar.org/browse/material-type/6/glass
subject: Metal
valueUri: https://core.tdar.org/browse/material-type/11/metal
subject: Shipwrecks
valueUri: https://core.tdar.org/browse/other-keyword/86578/shipwrecks
subject: Data Recovery
valueUri: https://core.tdar.org/browse/other-keyword/787/data-recovery
subject: Mapping
valueUri: https://core.tdar.org/browse/other-keyword/19875/mapping
subject: Underwater Archaeology
valueUri: https://core.tdar.org/browse/other-keyword/4198/underwater-archaeology
subject: Penobscot Expedition of 1779
valueUri: https://core.tdar.org/browse/other-keyword/166486/penobscot-expedition-of-1779
subject: Remote Sensing
valueUri: https://core.tdar.org/browse/other-keyword/3929/remote-sensing
subject: Archaeological Investigation
valueUri: https://core.tdar.org/browse/other-keyword/46172/archaeological-investigation
subject: Data Recovery / Excavation
valueUri: https://core.tdar.org/browse/investigation-type/5/data-recovery-excavation
subject: Reconnaissance / Survey
valueUri: https://core.tdar.org/browse/investigation-type/7/reconnaissance-survey

description: This is the final report of a site assessment and multi-component remote-sensing survey of the Penobscot River, Penobscot County, Maine. The project was part of an ongoing effort to research, investigate, and document shipwrecks and other submerged archaeological sites associated with the Penobscot Expedition of 1779, and ultimately develop a management plan for their protection and preservation.
Dual forward packet traffic channel and optimized data rate selection for IS-856 (cdma2000 1 x EV-DO)
Creators: name: Dost, Serkan
Publisher: name: University of British Columbia
Year: 2009

description: The IS-856 (cdma2000 1xEV-DO) standard is designed with the intention of only providing delay tolerant high rate data services for cdma2000 systems. It uses packet switched transmission by transmitting only one packet at a time using the entire transmission bandwidth. It uses adaptive data rate transmission by transmitting to users at the highest data rate supportable by the channel. It takes advantage of multiple user environment by selecting users based on the user's channel conditions at the time of transmission. In this thesis, improvements to the performance of the IS-856 system in terms of average system data rates and packet delays are considered. A modification to the downlink to include a second downlink packet channel is proposed . To take advantage of the two user transmission, existing packet scheduling algorithms are modified to schedule two users simultaneously. Simulations including physical layer and system level are used to determine the performance of the proposed system. The modification gives an increase in average data rates and decrease in packet delays. The repetition coding used by the system allows for the creation of variable data rates. In the thesis, a set of optimized data rates are generated for a selected channel model. The data rates are optimized for single user transmission and for two user transmission. These optimized data rates show a performance gain for the system.
Panoramic GALEX FUV and NUV imaging of M31 and M33
Creators: name: Thilker, D. A.
name: Hoopes, C. G.
name: Bianchi, L.
name: Boissier, S.
name: Rich, M.
name: Seibert, M.
name: Friedman, P. G.
name: Rey, S.
name: Buat, V.
name: Barlow, T. A.
name: Byun, Y.
name: Donas, J.
name: Forster, K.
name: Heckman, T. M.
name: Jelinsky, P. N.
name: Lee, Y.
name: Madore, B. F.
name: Malina, R. F.
name: Martin, C.
name: Milliard, B.
name: Morrissey, P. F.
name: Neff, S. G.
name: Schiminovich, D.
name: Siegmund, O. H. W.
name: Small, T.
name: Szalay, A. S.
name: Welsh, B. Y.
name: Wyder, T. K.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present Galaxy Evolution Explorer (GALEX) far-UV and near-UV mosaic observations covering the entirety of M31 and M33. For both targets, we measure the decline of surface brightness (in FUV and NUV) and changes in FUV--NUV color as a function of galactocentric radius. These UV radial profiles are compared to the distribution of ionized gas traced by H-alpha emission. We find that the extent of the UV emission, in both targets, is greater than the extent of the observed HII regions and diffuse ionized gas. We determine the ultraviolet diffuse fraction in M33 using our FUV observations and compare it to the H-alpha diffuse fraction obtained from wide-field narrow-band imaging. The FUV diffuse fraction appears to be remarkably constant near 0.65 over a large range in galactocentric radius, with departures to higher values in circumnuclear regions and, most notably, at the limit of the H-alpha disk. We suggest that the increase in FUV diffuse fraction at large galactocentric radii could indicate that a substantial portion of the diffuse emission beyond this point is not generated in situ but rather scattered from dust, after originating in the vicinity of the disk's outermost HII regions. Radial variation of the H-alpha diffuse fraction was also measured. We found the H-alpha diffuse fraction generally near 0.4 but rising toward the galaxy center, up to 0.6. We made no attempt to correct our diffuse fraction measurements for position-dependent extinction, so the quoted values are best interpreted as upper limits given the plausibly higher extinction for stellar clusters relative to their surroundings.
description: This paper will be published as part of the Galaxy Evolution Explorer (GALEX) Astrophysical Journal Letters Special Issue. Links to the full set of papers will be available at http://www.galex.caltech.edu/PUBLICATIONS/ after November 22, 2004. Individual high-resolution figures can be found at http://dolomiti.pha.jhu.edu/publgoto.html
Using Weak Lensing to find Halo Masses
Creators: name: de Putter, Roland
name: White, Martin
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Since the strength of weak gravitational lensing is proportional to the mass along the line of sight, it might be possible to use lensing data to find the masses of individual dark matter clusters. Unfortunately, the effect on the lensing field of other matter along the line of sight is substantial. We investigate to what extent we can correct for these projection effects if we have additional information about the most massive halos along the line of sight from deep optical data. We conclude that unless we know the masses and positions of halos down to a very low mass, we can only correct for a small part of the line-of-sight projection, which makes it very hard to get accurate mass estimates of individual halos from lensing data.
description: 16 pages, 9 figures, to be submitted to New Astronomy
Influence of interlocked transactions on gum arabic production and marketing in Senegal
Creators: name: Mujawamariya, Gaudiose
name: D'Haese, Marijke F.C.
name: Burger, Kees
name: Mujawamariya, Gaudiose
name: D'Haese, Marijke F.C.
name: Burger, Kees
Publisher: name: Unknown
Year: 2010
Subjects: subject: Marketing
subject: FOS: Economics and business

description: Interlocked relationships are characterised by traders’ supply of inputs and cash to producers on credit, to be reimbursed at sale time based on a pre-defined price which is often lower than the prevailing market price. The study analyses determinants of choice of interlocking in the gum sector in Senegal and the effect of interlocking on market participation and gum production. Data from 422 gum producers in Northern and Eastern regions of Senegal are used. About 41% of respondents are involved into interlocking with village shop-owners or mobile traders. Interlocking positively influences market participation and production as found through a Heckman selection model.
Reconsidering the origin of the 21 micron feature: Oxides in carbon-rich PPNe?
Creators: name: Posch, Thomas
name: Mutschke, Harald
name: Andersen, Anja C.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The origin of the so-called "21 micron" feature which is especially prominent in the spectra of some carbon-rich protoplanetary nebulae (PPNe}) is the matter of a lively debate. A large number of potential band carriers have been presented and discarded within the past decade. The present paper gives an overview of the problems related to the hitherto proposed feature identifications, including the recently suggested candidate carrier silicon carbide. We also discuss the case for spectroscopically promising oxides. SiC is shown to produce a strong resonance band at 20-21 micron if coated by a layer of silicon dioxide. At low temperatures, core-mantle particles composed of SiC and amorphous SiO$_2$ indeed have their strongest spectral signature at a position of 20.1 micron, which coincides with the position of the "21 micron" emission band. The optical constants of another candidate carrier that has been relatively neglected so far -- iron monoxide -- are proven to permit a fairly accurate reproduction of the "21 micron" feature profile as well, especially when low-temperature measurements of the infrared properties of FeO are taken into account. As candidate carrier of the "21 micron" emission band, FeO has the advantage of being stable against further oxidation and reduction only in a narrow range of chemical and physical conditions, coinciding with the fact that the feature, too, is detected in a small group of objects only. However, it is unclear how FeO should form or survive particularly in carbon-rich PPNe.
description: 28 pages, 15 figures, accepted for publication in ApJ (December)
Why some community forests are performing better than others: a case of forest user groups in Nepal
Creators: name: Chand, Narendra
name: Kerr, Geoffrey N.
name: Bigsby, Hugh R.
name: Chand, Narendra
name: Kerr, Geoffrey N.
name: Bigsby, Hugh R.
Publisher: name: Unknown
Year: 2010
Subjects: subject: Community/Rural/Urban Development
subject: Environmental Economics and Policy
subject: Farm Management
subject: Productivity Analysis
subject: Community forestry
subject: stochastic frontier
subject: production efficiency
subject: Nepal

description: Management of many Nepalese forests has been devolved to local communities. Forest products, which are used by the community and which may also be traded, are essential contributors to community well-being. Forests are also important contributors of ecosystem services, such as flood protection and wildlife habitat. Nepalese communities were surveyed to measure flows of forest products from their community forests. A stochastic frontier analysis shows that communities are not producing forest products efficiently and there is potential for improvement. The results shows that forest products benefit and environmental performance are associated products. In addition, analysis reveals that factors such as social capital, support from government and knowledge in management contributes positively to the production efficiency. It is anticipated that these findings will contribute to community forest policy redesign and consequently to the welfare of communities.
Recovering from conflict: an analysis of food production in Burundi
Creators: name: D'Haese, Marijke F.C.
name: Speelman, Stijn
name: Vandamme, Ellen
name: Nkunzimana, Tharcisse
name: Ndimubandi, Jean
name: D'Haese, Luc
name: D'Haese, Marijke F.C.
name: Speelman, Stijn
name: Vandamme, Ellen
name: Nkunzimana, Tharcisse
name: Ndimubandi, Jean
name: D'Haese, Luc
Publisher: name: Unknown
Year: 2010
Subjects: subject: International Development
subject: food security
subject: post-conflict
subject: Central Africa
subject: Burundi
subject: subsistence farming
subject: poverty trap

description: This paper deals with the devastating food insecurity in two densely populated provinces in the north of Burundi as a result of overpopulation and low production capacity in the aftermath of conflict. We compare data that was collected in the Ngozi and Muyinga Province in 2007 with data of households interviewed on the same hills in 1996. Households live from subsistence farming, erratic surplus sales, sales of coffee and banana and occasional off- and non-farm work. We find that not only did production levels decrease but also total factor productivity (Malmquist indices calculated with DEA approach) dropped in 83% of the hills between 1996 and 2007.
Search for a Charged Partner of the X(3872) in the B Meson Decay B --> X- K, X- --> J/psi pi- pi0
Creators: name: Aubert, B.
name: Collaboration, BaBar
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We search for a charged partner of the X(3872) in the decay B --> X- K, X- --> J/psi pi- pi0, using 234 million BBbar events collected at the Y(4S) resonance with the BaBar detector at the PEP-II e+e- asymmetric-energy storage ring. The resulting product branching fraction upper limits are BR(B0 --> X- K+, X- --> J/psi pi- pi0) < 5.4 x 10(-6) and BR(B- --> X- K0bar,X- --> J/psi pi- pi0) < 22 x 10(-6) at the 90% confidence level.
description: 8 pages, 3 postscript figues, submitted to Phys. Rev. D (Rapid Communications)
Land Management Practices and Their Effects on Food Crop Yields in Ghana
Creators: name: Asuming-Brempong, Samuel
name: Asuming-Brempong, Samuel
Publisher: name: Unknown
Year: 2010
Subjects: subject: Land Economics/Use
subject: Land Management
subject: Crop Yields
subject: Ecological Zones
subject: Productivity
subject: Practices

description: Agricultural land use and the management of agricultural lands in Ghana as evidenced from farmer practices have been analysed using descriptive and regression analysis. The analysis shows that different land management practices affect crop yields differently in the different ecological zones. Also, the types of land management practices farmers use differ across the different ecological zones. The policy implication is that agricultural interventions should be developed on the basis of agro-ecological zones, and blanket crop improvement packages should be avoided. The recommended policy action is that food crop farmers should be helped to improve the management of their agricultural lands by ecological zones at two levels. First, the practices that are common and promote agricultural production in each zone should be targeted for improvement. Such a policy will re-orient farmers towards the adoption of more sustainable farm practices. Second, land management practices that are not currently being used by farmers in each zone but have potential to improve crop production should be identified and promoted in the respective agro-ecological zones. A pro-active policy of this kind will provide farmers better land use alternatives in each ecological zone.
The inverse proximity effect in strong ferromagnet-superconductor structures
Creators: name: Yagovtsev, Vladimir
name: Pugach, Natalia
name: Eschrig, Matthias
Publisher: name: arXiv
Year: 2020
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The magnetization in a superconductor induced due to the inverse proximity effect is investigated in hybrid bilayers containing a superconductor and a ferromagnetic insulator or a strongly spin-polarized ferromagnetic metal. The study is performed within a quasiclassical Green function framework, wherein Usadel equations are solved with boundary conditions appropriate for strongly spin-polarized ferromagnetic materials. A comparison with recent experimental data is presented. The singlet to triplet conversion of the superconducting correlations as a result of the proximity effect with a ferromagnet is studied.
description: 10 pages, 6 figures Submitted to "Superconductor Science and Technology" journal
Viabilidade econômica da irrigação da cultura do café na região de Viçosa - MG
Creators: name: Aredes, Alan Figueiredo De
name: Santos, Maurinho Luiz Dos
name: Rufino, Jose Luiz Dos Santos
name: Reis, Bricio Dos Santos
name: Aredes, Alan Figueiredo De
name: Santos, Maurinho Luiz Dos
name: Rufino, Jose Luiz Dos Santos
name: Reis, Bricio Dos Santos
Publisher: name: Unknown
Year: 2007
Subjects: subject: Risk and Uncertainty
subject: Coffee
subject: Return
subject: Risk

description: The objective of this paper is analyze the economic viability of implanting different technological alternatives of irrigation in the culture of coffee in the municipal district of Viçosa-MG. Technical and financial parameters of coffee cultivation were analyzed in five different technological alternatives: (A) - no-irrigated production with low productivity, (B) - no-irrigated production with high productivity, (C) - irrigated production by leaking, (D) - irrigated production by leaking fertilizing, (E) - irrigated production by mesh. For each one of there alternatives, Present Value, Internal Rate of Return, the Rate Interns of Return Modified and the Payback Period, being made the risk simulations were performed using the Latin Hypercube method. Results showed that the alternatives of production white irrigated were economically superior to the alternatives without no-irrigated, even in traditional producers areas, as the municipal district of Viçosa-MG. In addition to elevating the economical return and reducing the of the Payback Period capital invested, irrigated coffee reduces the risk of the activity.
Relações de troca com efeito tecnológico no mercado doméstico de arroz, milho, café e soja
Creators: name: Ponciano, Niraldo Jose
name: Souza, Paulo Marcelo De
name: Mata, Henrique Tome Da Costa
name: Detmann, Edenio
name: Ponciano, Niraldo Jose
name: Souza, Paulo Marcelo De
name: Mata, Henrique Tome Da Costa
name: Detmann, Edenio
Publisher: name: Unknown
Year: 2007
Subjects: subject: Productivity Analysis
subject: Terms of exchange
subject: Grains
subject: Inputs
subject: Prices
subject: Productivity
subject: Income

description: The objective of this work was to evaluate, by means of the exchange rate, the profitability of two products directed toward the domestic market and two export products. Other objective was to identify productivity growth compensated the decrease of prices. The geometric rates of the production, area and productivity growth were estimated. The exchange rate was estimated by the relation between the index of the inputs prices and the index of the product prices. The results show a great trend of deterioration of the exchange terms for all the analyzed products. Evidenced that these effects more was been accented for rice and maize. Such behavior associates it the fact of the rice cultures and of maize to be destined to the domestic market, its demands have been not elastic in relation to the coffee and soy cultures.
Percepção e respostas gerenciais ao risco: um estudo sobre os produtores de leite do Programa de Desenvolvimento da Pecuária Leiteira da Região de Viçosa - MG
Creators: name: Vale, Sonia Maria Leite Ribeiro Do
name: Pereira, Vanessa Da Fonseca
name: Lima Neto, Antonio Carlos
name: Sant'Anna, Julio Cezar Oliveira
name: Vale, Sonia Maria Leite Ribeiro Do
name: Pereira, Vanessa Da Fonseca
name: Lima Neto, Antonio Carlos
name: Sant'Anna, Julio Cezar Oliveira
Publisher: name: Unknown
Year: 2007
Subjects: subject: Risk and Uncertainty
subject: Agricultural risk management
subject: Information

description: The agriculture sector has particular characteristics, general and unfavorable, which make its participants exposed to risks, and increase the complexity of making decisions. However, little is known about how farmers perceive risk in their activity. Based on a research done in the Zona da Mata region in the State of Minas Gerais, this work shows the view of a group of milk producers about the risks which they are exposed to, and also, describes the tools used by them as managing responses to these risks. Firstly, the farmers answered about the importance of the different kinds of risks in their business, and next, pointed out the methods they use to manage them. The results show the lack of a formal risk managing strategy, which has been substituted up to the moment, by the farmers’ experience and, consequently, their familiarity with the marketing.
A influência da exportação de açúcar no porto de Santos sobre o frete rodoviário do fertilizante no estado de São Paulo
Creators: name: Antonio, Joao Paulo Gomes Rigueiral E
name: Carvalho, Leandro Bernardino De
name: Antonio, Joao Paulo Gomes Rigueiral E
name: Carvalho, Leandro Bernardino De
Publisher: name: Unknown
Year: 2007
Subjects: subject: Marketing
subject: FOS: Economics and business
subject: Agro-industrial logistic
subject: Linear regression
subject: Pearson's correlation
subject: Distribution of fertilizer

description: This survey has the purpose to prove as and how much the volume of exported sugar by Santos port interferes in the freight value negotiated for fertilizer distribution for the final customer, in São Paulo State. For people who are directly connected to fertilizer logistic, it is very important to have knowledge of how this variable impact in its market and so, it is possible to plan and make feasible differential logistic strategies to can provide more competitiveness for its business. Through statistics methodology, it is possible to observe and quantify the influence of main variable that has interference in the delivery road freight to the final customer. Based on this, it will be able to conclude that the logistic linking between sugar and fertilizer will be closer, due to strong relationships and it will depend on both bases and its commercial interests.
Key Challenges and Options Confronting Smallholder, Agribusiness and Government Leaders in Zambia's Cotton Sector
Creators: name: Jayne, Thomas S.
name: Jayne, Thomas S.
Publisher: name: Unknown
Year: 2000
Subjects: subject: Agribusiness
subject: Farm Management
subject: food security
subject: food policy
subject: Zambia
subject: cotton

description: This policy brief highlights some of the key messages contained in the full report. However the problems and opportunities facing the industry are very complex, and cannot be easily summarized in this brief. Hence one goal of this policy brief is to encourage interested parties to obtain, review and debate the full study. A second objective of this brief is to highlight the strategic industry development questions and proposals identified in the study that require debate and follow up actions.