cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Longitudinal development of extensive air showers: hybrid code SENECA and full Monte Carlo
Creators: name: Ortiz, Jeferson A.
name: Tanco, Gustavo Medina
name: de Souza, V.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: New experiments, exploring the ultra-high energy tail of the cosmic ray spectrum with unprecedented detail, are exerting a severe pressure on extensive air hower modeling. Detailed fast codes are in need in order to extract and understand the richness of information now available. Some hybrid simulation codes have been proposed recently to this effect (e.g., the combination of the traditional Monte Carlo scheme and system of cascade equations or pre-simulated air showers). In this context, we explore the potential of SENECA, an efficient hybrid tridimensional simulation code, as a valid practical alternative to full Monte Carlo simulations of extensive air showers generated by ultra-high energy cosmic rays. We extensively compare hybrid method with the traditional, but time consuming, full Monte Carlo code CORSIKA which is the de facto standard in the field. The hybrid scheme of the SENECA code is based on the simulation of each particle with the traditional Monte Carlo method at two steps of the shower development: the first step predicts the large fluctuations in the very first particle interactions at high energies while the second step provides a well detailed lateral distribution simulation of the final stages of the air shower. Both Monte Carlo simulation steps are connected by a cascade equation system which reproduces correctly the hadronic and electromagnetic longitudinal profile. We study the influence of this approach on the main longitudinal characteristics of proton-induced air showers and compare the predictions of the well known CORSIKA code using the QGSJET hadronic interaction model.
description: 11 pages (LaTeX), 15 postscript figures, 3 tables
Supplemental File 1
Creators: name: Manjarin, Rodrigo
Publisher: name: figshare
Year: 2020
Subjects: subject: 70204 Animal Nutrition
subject: FOS: Animal and dairy science
subject: 70299 Animal Production not elsewhere classified

description: Probiotic detection and viability in diets and gastrointestinal tract
Thickness-dependent electron momentum relaxation times in iron films
Creators: name: Krewer, K. L.
name: Zhang, W.
name: Arabski, J.
name: Schmerber, G.
name: Beaurepaire, E.
name: Bonn, M.
name: Turchinovich, D.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: Terahertz time-domain conductivity measurements in 2 to 100 nm thick iron films resolve the femtosecond time delay between applied electric fields and resulting currents. This current response time decreases from 29 fs for thickest films to 7 fs for the thinnest films. The macroscopic response time is not strictly proportional to the conductivity. This excludes the existence of a single relaxation time universal for all conduction electrons. We must assume a distribution of microscopic momentum relaxation times. The macroscopic response time depends on average and variation of this distribution; the observed deviation between response time and conductivity scaling corresponds to the scaling of the variation. The variation of microscopic relaxation times depends on film thickness because electrons with different relaxation times are affected differently by the confinement since they have different mean free paths.
description: 9 pages, 6 figures
An ex-ante analysis of distributional effects of the CAP on western German farm incomes
Creators: name: Deppermann, Andre
name: Grethe, Harald
name: Offermann, Frank
name: Deppermann, Andre
name: Grethe, Harald
name: Offermann, Frank
Publisher: name: Unknown
Year: 2011
Subjects: subject: Agricultural and Food Policy
subject: Income distribution
subject: CAP
subject: Farm Group Model
subject: Equilibrium Model

description: This study is concerned with measuring impacts of the Common Agricultural Policy (CAP) on farm income distribution of western Germany. Not only the sheer contribution of market price support and direct payments as a proportion of income is taken into account, but also the impact of support on production incentives. For this purpose, we apply a modelling system consisting of a partial equilibrium model and a programming model. Based on a comparison of Gini coefficients and a decomposition of overall inequality effects we conclude that liberalization of the agricultural sector leads to a more unequal distribution of family farm income in relative terms, whereas a liberalized market provides a more equal situation in absolute terms.
Magnetic order in the normal state of the archetypal high-Tc superconductor La2-xSrxCuO4
Creators: name: Panagopoulos, C.
name: Majoros, M.
name: Nishizaki, T.
name: Iwasaki, H.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We report detailed bulk magnetization measurements of the normal state in the high transition temperature (high-Tc) superconductor La2-xSrxCuO4. A magnetic order in the form of hysteresis in the low field magnetization was observed at temperatures well above Tc but below the pseudogap temperature. The order arises from the interaction of magnetic domains, and the doping (x) dependence of its onset and strength broadly follows that of Tc(x).
description: More data and discussion, better signal to noise
Pricing Options on Commodity Futures: The Role of Weather and Storage
Creators: name: Bozic, Marin
name: Fortenbery, T. Randall
name: Bozic, Marin
name: Fortenbery, T. Randall
Publisher: name: Unknown
Year: 2011
Subjects: subject: Agribusiness
subject: Agricultural Finance
subject: Crop Production/Industries
subject: Financial Economics
subject: Research Methods/ Statistical Methods
subject: Risk and Uncertainty
subject: arbitrage pricing model
subject: options on futures
subject: generalized lambda distribution
subject: theory of storage
subject: skewness

description: Options on agricultural futures are popular financial instruments used for agricultural price risk management and to speculate on future price movements. Poor performance of Black’s classical option pricing model has stimulated many researchers to introduce pricing models that are more consistent with observed option premiums. However, most models are motivated solely from the standpoint of the time series properties of futures prices and need for improvements in forecasting and hedging performance. In this paper we propose a novel arbitrage pricing model motivated from the economic theory of optimal storage, and consistent with implications of plant physiology on the importance of weather stress. We introduce a pricing model for options on futures based on a Generalized Lambda Distribution (GLD) that allows greater flexibility in higher moments of the expected terminal distribution of futures price. We use times and sales data for corn futures and options for the period 1995-2009 to estimate the implied skewness parameter separately for each trading day. An economic explanation is then presented for inter-year variations in implied skewness based on the theory of storage. After controlling for changes in planned acreage, we find a statistically significant negative relationship between ending stocks-to-use and implied skewness, as predicted by the theory of storage. Furthermore, intra-year dynamics of implied skewness reflect the fact that resolution of uncertainty in corn supply is resolved between late June and middle of October, i.e. during corn growth phases that encompass corn silking through grain maturity. Impacts of storage and weather on the distribution of terminal futures price jointly explain upward sloping implied volatility curves.
Stellar angular momentum distribution linked to galaxy morphology
Creators: name: Sweet, Sarah M.
name: Glazebrook, Karl
name: Obreschkow, Danail
name: Fisher, Deanne B.
name: Burkert, Andreas
name: Lagos, Claudia D. P.
name: Salcedo, Juan M. Espejo
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We study the spatially-resolved stellar specific angular momentum $j_*$ in a high-quality sample of 24 CALIFA galaxies covering a broad range of visual morphology, accounting for stellar velocity and velocity dispersion. The shape of the spaxel-wise probability density function of normalised $s=j_*/j_{*mean}$, PDF($s$), deviates significantly from the near-universal initial distribution expected of baryons in a dark matter halo and can be explained by the expected baryonic effects in galaxy formation that remove and redistribute angular momentum. Further we find that the observed shape of the PDF($s$) correlates significantly with photometric morphology, where late-type galaxies have PDF($s$) that is similar to a normal distribution, whereas early types have a strongly-skewed PDF($s$) resulting from an excess of low-angular momentum material. Galaxies that are known to host pseudobulges (bulge Sersic index $n_b <2.2$) tend to have less skewed bulge PDF($s$), with skewness $(b_{1rb})\lesssim0.8$. The PDF($s$) encodes both kinematic and photometric information and appears to be a robust tracer of morphology. Its use is motivated by the desire to move away from traditional component-based classifications which are subject to observer bias, to classification on a galaxy's fundamental (stellar mass, angular momentum) properties. In future, PDF($s$) may also be useful as a kinematic decomposition tool.
description: 19 pages, 11 figures, accepted for publication in MNRAS
Climate-smart agriculture: ecosystem services in mixed farming and agroforestry systems
Creators: name: Venn, Rosemary
name: Dehnen-Schmutz, Katharina
name: Allen, Michelle
Publisher: name: AGROMIX
Year: 2022

description: The aim of this report is to evaluate the ecosystem services and disservices present in mixed farming and agroforestry systems and to assess their relative importance in relation to climate smart agriculture, from a farmers’ perspective. An online survey was conducted to gather farmer perceptions of agricultural practices in relation to on-farm resilience , ecosystem services and contribution to climate change mitigation Despite the small data set (44 responses), some general conclusions can be drawn. Almost all farms had experienced extreme weather in the last five years and the vast majority of farmers plan to improve ecosystem services on their farm. The top 5 ecosystem services farmers would like to improve are: carbon sequestration; carbon cycling; enhanced soil fertility; education value; and nitrogen fixation. Farmers cited money and time as the top two requirements for improving ecosystem services on farm. The top 5 practices cited by all farm types to reduce the effects of extreme weather were: keeping the soil covered; increasing diversity of crops; rotational grazing; incorporating trees; and growing indigenous species.
Theory of BCS-like bogolon-mediated superconductivity in transition metal dichalcogenides
Creators: name: Sun, Meng
name: Parafilo, A.
name: Villegas, K. H. A.
name: Kovalev, V. M.
name: Savenko, I. G.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We report on a novel mechanism of BCS-like superconductivity, mediated by a pair of Bogoliubov quasiparticles (bogolons). It takes place in hybrid systems consisting of a two-dimensional electron gas in a transition metal dichalcogenide monolayer in the vicinity of a Bose-Einstein condensate. Taking a system of two-dimensional indirect excitons as a testing ground we show, that the bogolon-pair-mediated electron pairing mechanism is stronger than phonon-mediated and single bogolon-mediated ones. We develop a microscopic theory of bogolon-pair-mediated superconductivity, based on the Schrieffer-Wolff transformation and the Gor'kov's equations, study the temperature dependence of the superconducting gap and estimate the critical temperature of superconducting transition for various concentrations of the electron gas and the condensate densities.
description: Manuscript: 6 pages, 4 figures
Can there be any new physics in b -> d penguins
Creators: name: Giri, A. K.
name: Mohanta, R.
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We analyze the possibility of observing new physics effects in the $b \to d$ penguin amplitudes. For this purpose, we consider the decay mode $B \to K^0 \bar K^0 $, which has only $b \to d$ penguin contributions. Using the QCD factorization approach, we find very tiny CP violating effects in the standard model for this process. Furthermore, we show that the minimal supersymmetric standard model with $LR$ mass insertion and R-parity violating supersymmetric model can provide substantial CP violation effects. Observation of sizable CP violation in this mode would be a clear signal of new physics.
description: Published version
Optimal Preservation of Agricultural and Environmental Land within a Municipality Under Irreversibility and Uncertainty
Creators: name: Howard, Peter H.
name: Howard, Peter H.
Publisher: name: Unknown
Year: 2011
Subjects: subject: Environmental Economics and Policy
subject: Land Economics/Use
subject: Political Economy
subject: Risk and Uncertainty
subject: Uncertainty
subject: Irreversibility
subject: Spatial-temporal modeling
subject: Value of information
subject: Policy design
subject: Climate change
subject: Agricultural preservation
subject: Environmental conservation

description: This paper analyzes the optimal policy choice for the conservation of privately owned open space when future land cover types are uncertain. Policymakers must use land use policies to make conservation decisions under uncertainty over the social benefits of future vegetation, due to the uncertain effects of climate change on suitable habitat ranges. If policymakers fail to account for future information gains when designing land use policies, expected social welfare may not be maximized. To examine this situation, I consider three policy instruments: urban growth boundaries (UGB), location-independent development fees (LIF), and location-dependent development fees (LDF). I analyze them in a spatial-dynamic model in which climate change is treated as a land use externality with an uncertain future value. I derive the privately and socially optimal land allocations under open-loop and closed-loop control. By comparing the privately and socially optimal land allocations for each control problem, I identify the optimal trajectory of each instrument over time. Results depend on whether or not there is a cumulative externality from urban development. When no cumulative externality exists, welfare-maximizing UGB and LIF depend on the control problem. In contrast, LDF are identical in expectation across the two control problems. As a consequence, LDF are the first best policy when landowners do and policymakers do not anticipate (or cannot respond to) the future availability of climatic information. When a cumulative externality exists, none of the policies are robust to the type of control problem, including LDF, and only UGB are time consistent. Therefore, UGB are the first best policy when policymakers anticipate future climatic information and there is a cumulative externality. This work implies that conservation programs should amend current methods for ranking conservation choices to account for future ecosystem movement, and return lands to other uses if climate change causes conservation goals to not be achieved.
description: Replaced with revised version of paper 07/22/11.
Joint Hand-object 3D Reconstruction from a Single Image with Cross-branch Feature Fusion
Creators: name: Chen, Yujin
name: Tu, Zhigang
name: Kang, Di
name: Chen, Ruizhi
name: Bao, Linchao
name: Zhang, Zhengyou
name: Yuan, Junsong
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Accurate 3D reconstruction of the hand and object shape from a hand-object image is important for understanding human-object interaction as well as human daily activities. Different from bare hand pose estimation, hand-object interaction poses a strong constraint on both the hand and its manipulated object, which suggests that hand configuration may be crucial contextual information for the object, and vice versa. However, current approaches address this task by training a two-branch network to reconstruct the hand and object separately with little communication between the two branches. In this work, we propose to consider hand and object jointly in feature space and explore the reciprocity of the two branches. We extensively investigate cross-branch feature fusion architectures with MLP or LSTM units. Among the investigated architectures, a variant with LSTM units that enhances object feature with hand feature shows the best performance gain. Moreover, we employ an auxiliary depth estimation module to augment the input RGB image with the estimated depth map, which further improves the reconstruction accuracy. Experiments conducted on public datasets demonstrate that our approach significantly outperforms existing approaches in terms of the reconstruction accuracy of objects.
description: Accepted by IEEE Transactions on Image Processing (TIP)
Measuring the Welfare Loss to Landowners of Future Geographic Shifts In the Suitable Habitat for Vegetation Due to Climate Change
Creators: name: Howard, Peter H.
name: Howard, Peter H.
Publisher: name: Unknown
Year: 2011
Subjects: subject: Consumer/Household Economics
subject: Demand and Price Analysis
subject: Environmental Economics and Policy
subject: Land Economics/Use
subject: Hedonic
subject: Multi-scale capitalization
subject: Housing demand
subject: Species distribution model
subject: Climate change
subject: Displacement of native species
subject: Vegetation movement
subject: Geographic Information System (GIS)
subject: Amenity value
subject: Land use

description: Scientists predict that global warming will cause suitable habitat ranges to shift for many plant species, including blue oak in California. If proximity to particular land cover types significantly affects human welfare, any such shifts will affect household welfare, resulting in an indirect cost that is currently unaccounted for in the climate change literature. Using a hedonic pricing model, the marginal values of blue oaks and the land cover types most likely to replace them are estimated at multiple spatial scales using single family residences sold in Kern County from 1997 to 2003. In addition to the common identification problems of specification error and omitted variable bias, the variables measuring the degree of proximity of a property to land cover types are endogenous. To identify the marginal values of land cover types at multiple spatial scales using two-stage least squares, instrumental variables are developed using soil data. The results show that the value of blue oaks and other land cover types capitalize at different spatial scales, and these values differ at these various scales. The overall welfare effect of a marginal loss of blue oaks depends on the spatial distribution of the surrounding population, its spatial relationship with respect to blue oaks, and the type of vegetation that replaces blue oaks. With respect to the goal of maximizing social welfare, these results suggest that blue oaks should be preserved from agricultural and urban development in some, but not all, situations.
An Agent-Based Model of Exurban Land Development
Creators: name: Chen, Yong
name: Irwin, Elena G.
name: Jayaprakash, Ciriyam
name: Chen, Yong
name: Irwin, Elena G.
name: Jayaprakash, Ciriyam
Publisher: name: Unknown
Year: 2011
Subjects: Land Economics/Use

description: In contrast to urban areas that are aptly characterized by a large population base and scarce land supply, exurban regions have limited households and plentiful land. This basic difference has far reaching implications for spatial equilibrium in exurban land markets. Rather than bidding their maximum willingness-to-pay and reaching a spatial equilibrium in which households are indifferent to location, as is the central condition of urban economic models, we argue that exurban households will be able to retain some amount of surplus in moving to an exurban location and therefore will choose the location that maximizes this locational surplus. In this paper, we first review the handful of structural spatial models of exurban land development that have been developed. We then develop a structural spatial model of exurban land development that captures these hypothesized features of exurban land markets using an auction model to represent household bidding and adapting the Capooza and Helsley (1990) model to represent landowners’ optimal timing of development. A key innovation of our approach is that, in the absence of full capitalization of land or location differences into land prices, households have preferences for some locations over others and thus it is possible to order household location choices in time and space. This greatly facilitates modeling of land use dynamics by enabling us to model location and land use decisions sequentially in time rather than assuming that all development is instantaneous for given levels of population and income in the region. In addition, the spatial agent-based simulation method that is used to implement the model permits an explicit examination of the implications of exurban land market conditions for the evolution of urban development pattern. Specifically, we ask whether these exurban market conditions explain the emergence and persistence of so-called leapfrog development that is characteristic of exurban regions.
Image Pre-processing on NumtaDB for Bengali Handwritten Digit Recognition
Creators: name: Paul, Ovi
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: NumtaDB is by far the largest data-set collection for handwritten digits in Bengali. This is a diverse dataset containing more than 85000 images. But this diversity also makes this dataset very difficult to work with. The goal of this paper is to find the benchmark for pre-processed images which gives good accuracy on any machine learning models. The reason being, there are no available pre-processed data for Bengali digit recognition to work with like the English digits for MNIST.
description: 5 pages, 8 figures and 4 tables
Real-space electronic-structure calculations with timesaving double-grid technique
Creators: name: Ono, Tomoya
name: Hirose, Kikuji
Publisher: name: arXiv
Year: 2004
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We present a set of efficient techniques in first-principles electronic-structure calculations utilizing the real-space finite-difference method. These techniques greatly reduce the overhead for performing integrals that involve norm-conserving pseudopotentials, solving Poisson equations, and treating models which have specific periodicities, while keeping a high degree of accuracy. Since real-space methods are inherently local, they have a lot of advantages in applicability and flexibility compared with the conventional plane-wave approach, and promise to be well suited for large and accurate {\it ab initio} calculations. In order to demonstrate the potential power of these techniques, we present several applications for electronic structure calculations of atoms, molecules and a helical nanotube.
description: 20 pages and 8 figures
Graduate recitals
Creators: name: Decock, Annelies
Publisher: name: University of British Columbia
Year: 2009

description: The thesis for the Master of Music degree in Orchestral Instrument Performance consists of two full- length recitals, or the equivalent, with emphasis on solo works, but also including representative chamber works. I performed these recitals on April 15th, 2003 and on March 2nd, 2004 in the UBC School of Music Recital Hall.
Space-Time Symmetries of Noncommutative Spaces
Creators: name: Calmet, Xavier
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We define a noncommutative Lorentz symmetry for canonical noncommutative spaces. The noncommutative vector fields and the derivatives transform under a deformed Lorentz transformation. We show that the star product is invariant under noncommutative Lorentz transformations. We then apply our idea to the case of actions obtained by expanding the star product and the fields taken in the enveloping algebra via the Seiberg-Witten maps and verify that these actions are invariant under these new noncommutative Lorentz transformations. We finally consider general coordinate transformations and show that the metric is undeformed.
description: 7 pages, v2: typos corrected, to appear in Phys. Rev. D
Broken into Pieces: ATLAS and Aliqa Uma as One Single Stream
Creators: name: Li, Ting S.
name: Koposov, Sergey E.
name: Erkal, Denis
name: Ji, Alexander P.
name: Shipp, Nora
name: Pace, Andrew B.
name: Hilmi, Tariq
name: Kuehn, Kyler
name: Lewis, Geraint F.
name: Mackey, Dougal
name: Simpson, Jeffrey D.
name: Wan, Zhen
name: Zucker, Daniel B.
name: Bland-Hawthorn, Joss
name: Cullinane, Lara R.
name: Da Costa, Gary S.
name: Drlica-Wagner, Alex
name: Hattori, Kohei
name: Martell, Sarah L.
name: Sharma, Sanjib
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present the first spectroscopic measurements of the ATLAS and Aliqa Uma streams from the Southern Stellar Stream Spectroscopic Survey ($S^5$), in combination with the photometric data from the Dark Energy Survey and astrometric data from $Gaia$. From the coherence of spectroscopic members in radial velocity and proper motion, we find out that these two systems are extremely likely to be one stream with discontinuity in morphology and density on the sky (the "kink" feature). We refer to this entire stream as the ATLAS-Aliqa Uma stream, or the AAU stream. We perform a comprehensive exploration of the effect of baryonic substructures and find that only an encounter with the Sagittarius dwarf $\sim 0.5$ Gyr ago can create a feature similar to the observed "kink". In addition, we also identify two gaps in the ATLAS component associated with the broadening in the stream width (the "broadening" feature). These gaps have likely been created by small mass perturbers, such as dark matter halos, as the AAU stream is the most distant cold stream known with severe variations in both the stream surface density and the stream track on the sky. With the stream track, stream distance and kinematic information, we determine the orbit of the AAU stream and find that it has been affected by the Large Magellanic Cloud, resulting in a misalignment between the proper motion and stream track. Together with the Orphan-Chenab Stream, AAU is the second stream pair that has been found to be a single stream separated into two segments by external perturbation.
description: 33 pages, 22 figures (including 1 movie), 3 tables. Accepted for publication in ApJ
Economic and Groundwater Use Implications of Climate Change and Bioenergy Feedstock Production in the Ogallala Aquifer Region
Creators: name: Wang, Weiwei
name: Park, Seong Cheol
name: McCarl, Bruce A.
name: Amosson, Stephen H.
name: Wang, Weiwei
name: Park, Seong Cheol
name: McCarl, Bruce A.
name: Amosson, Stephen H.
Publisher: name: Unknown
Year: 2011
Subjects: subject: Environmental Economics and Policy
subject: Land Economics/Use
subject: Resource /Energy Economics and Policy
subject: Groundwater
subject: Land Use Change
subject: Climate Change
subject: Bioenergy feedstock
subject: Dynamic Optimization Model
subject: Deficit Irrigation

description: The sustainable water use especially for irrigated agriculture in the Texas Panhandle Region is a major concern. A semi-arid climate and average low rainfalls results in little surface water being available year-round. The Ogallala Aquifer is the primary source of irrigation water in this region. The intensive irrigated agricultural production and growing livestock industry have led to substantial decline of water tables. Furthermore, climate change and growing bioenergy feedstock productions exacerbates the water shortage and quality problems. Given the critical dependence of the regional economy on Ogallala Aquifer, underground water use is an intergenerational issue that must be evaluated in terms of the sustainability of agricultural activities in the long run. This paper develops a dynamic multi-county land allocation optimization model which integrates three sectors: agriculture, climate and hydrology. The sustainable water use and associated irrigated agricultural economic consequences under climate change are analyzed. This model also serves as a policy tool in evaluating economic impacts of alternative bioenergy expansion policies and water saving technologies in Ogallala Aquifer Region. The simulation results show that availability of extractable water has a direct impact on optimal land allocation. Deficit irrigation for major crops is an effective short-run strategy for water sustainability. In the longer run, dryland and pastureland farming will dominate. Climate change has heterogeneous impacts on agricultural production over counties and sub-counties because of the non-uniform hydrological characteristics.
Is negative kinetic energy meta-stable?
Creators: name: Gross, Christian
name: Strumia, Alessandro
name: Teresi, Daniele
name: Zirilli, Matteo
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We explore the possibility that theories with negative kinetic energy (ghosts) can be meta-stable up to cosmologically long times. In classical mechanics, ghosts undergo spontaneous lockdown rather than run-away if weakly-coupled and non-resonant. Physical examples of this phenomenon are shown. In quantum mechanics this leads to meta-stability similar to vacuum decay. In classical field theory, lockdown is broken by resonances and ghosts behave statistically, drifting towards infinite entropy as no thermal equilibrium exists. We analytically and numerically compute the run-away rate finding that it is cosmologically slow in 4-derivative gravity, where ghosts have gravitational interactions only. In quantum field theory the ghost run-away rate is naively infinite in perturbation theory, analogously to what found in early attempts to compute vacuum tunnelling; we do not know the true rate.
description: 40 pages, 6 figures; published version
Can the diversity of Singapore Marine Planktonic Eukaryotes be uncovered using culture methods?
Creators: name: Santos, Adriana Lopes Dos
name: Chua, Rae
Publisher: name: figshare
Year: 2020
Subjects: subject: 60504 Microbial Ecology
subject: FOS: Biological sciences
subject: 60205 Marine and Estuarine Ecology (incl. Marine Ichthyology)

description: Final Year thesis presented in June 2020 at School of Biological Sciences NTU
On the stability of the Brazilian presidential regime: a statistical analysis
Creators: name: Fetter, Frederico
name: Gamermann, Daniel
name: Brito, Carolina
Publisher: name: arXiv
Year: 2020
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Applications (stat.AP)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Brazil's presidential system is characterized by the existence of many political parties that are elected for the Chamber of Deputies and unite in legislative coalitions to form a majority. Since the re-democratization in 1985, Brazil has had 8 direct presidential elections, among which there were two impeachments of the elected president. In this work we characterize the stability of the presidential regime and the periods of rupture analysing the votes that took place in the Chamber of Deputies from 1991 to 2019. We start by measuring the cohesion of the parties and the congress in the votes, quantifying the agreement between the votes of congressmen and observe that there is a stronger polarization among congressmen during legislative periods where there was no impeachment, referred to here as stable legislative periods. Using clustering algorithms, we are able to associate these polarized groups observed during the stable periods with the opposition to the government and government base. To characterize the impeachment of Dilma Roussef that happened in 2016 we analyze how the agreement between congressmen and the government evolved over time and identified, using cluster algorithms, that all the parties belonging to the majority coalition of the president, except her own party and another one, migrated to the opposition just before the impeachment. Our analyses allow us to identify some differences between stable presidential periods and Legislative terms with an impeachment.
Spin-excitations of the quantum Hall ferromagnet of composite fermions
Creators: name: Doretto, R. L.
name: Goerbig, M. O.
name: Lederer, P.
name: Caldeira, A. O.
name: Smith, C. Morais
Publisher: name: arXiv
Year: 2004
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The spin-excitations of a fractional quantum Hall system are evaluated within a bosonization approach. In a first step, we generalize Murthy and Shankar's Hamiltonian theory of the fractional quantum Hall effect to the case of composite fermions with an extra discrete degree of freedom. Here, we mainly investigate the spin degrees of freedom, but the proposed formalism may be useful also in the study of bilayer quantum-Hall systems, where the layer index may formally be treated as an isospin. In a second step, we apply a bosonization scheme, recently developed for the study of the two-dimensional electron gas, to the interacting composite-fermion Hamiltonian. The dispersion of the bosons, which represent quasiparticle-quasihole excitations, is analytically evaluated for fractional quantum Hall systems at ν= 1/3 and ν= 1/5. The finite width of the two-dimensional electron gas is also taken into account explicitly. In addition, we consider the interacting bosonic model and calculate the lowest-energy state for two bosons. Besides a continuum describing scattering states, we find a bound-state of two bosons. This state is interpreted as a pair excitation, which consists of a skyrmion of composite fermions and an antiskyrmion of composite fermions. The dispersion relation of the two-boson state is evaluated for ν= 1/3 and ν= 1/5. Finally, we show that our theory provides the microscopic basis for a phenomenological non-linear sigma-model for studying the skyrmion of composite fermions.
description: Revised version, 14 pages, 4 figures, accepted to Phys. Rev. B
Asymptotic analysis of a line source diffraction by a perfectly conducting half-plane in a bi-isotropic medium
Creators: name: Hussain, Wasiq
Publisher: name: arXiv
Year: 2005
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 78M35, 78A25, 78A40, 78A45

description: This paper is concerned with the diffraction of an electromagnetic wave by a perfectly conducting half-plane in a homogeneous bi-isotropic medium (asymptotically). Similar analysis in a source-free field is done in Asghar,S. and Lakhtakia, A., (1994), Plane-wave diffraction by a perfectly conducting half-plane in a homogeneous bi-isotropic medium. Int. J Appl. Electromagnetics in materials,5,(1994), 181-188. In this paper attention is focused on the wave coming from a line source. The objective is to study the scattering of an electromagnetic wave from the boundary of a half-plane and thereby to provide a theoretical framework for the line source diffraction asymptotically. In far field approximation it is shown that an incident wave coming from a line source behaves like a plane wave. The scattered field is calculated by using the Fourier transform and the Wiener-Hopf techniques. The scattered field in the far zone is determined by using contour integration.
description: 18 pages
Relativistic supersymmetric quantum mechanics based on Klein-Gordon equation
Creators: name: Znojil, Miloslav
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Witten's non-relativistic formalism of supersymmetric quantum mechanics was based on a factorization and partnership between Schroedinger equations. We show how it accommodates a transition to the partnership between relativistic Klein-Gordon equations. In such a class of models the requirement of supersymmetry is shown to lead to a certain "exceptional-point" instability of ground states.
description: 20 pages
On anomalies in effective models with nonlinear symmetry realization
Creators: name: Arbuzov, Andrej
name: Latosh, Boris
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Anomalous features of models with nonlinear symmetry realization are addressed. It is shown that such models can have anomalous amplitudes breaking of its original symmetry realization. An illustrative example of a simple models with a nonlinear conformal symmetry realization is given. It is argued that the effective action obtained via nonlinear symmetry realization should be used to obtain an anomaly-induced action which is to drive the low energy dynamics.
description: Accepted to Modern Physics Letters A
Data from: Climbing rice plants above the waterline: escape of freshwater snails from underwater predation by snail-eating specialists
Creators: name: Hayashi, Masakazu
name: Sugiura, Shinji
Publisher: name: figshare
Year: 2020
Subjects: subject: Ecology
subject: FOS: Biological sciences

description: Hayashi M, Sugiura S (2020) Climbing rice plants above waterline: escape of freshwater snails from underwater predation by snail-eating specialists. Biological Journal of the Linnean Society (http://dx.doi.org/10.1093/biolinnean/blaa087)
Blowup of smooth solutions for relativistic Euler equations
Creators: name: Pan, Ronghua
name: Smoller, Joel A.
Publisher: name: arXiv
Year: 2005
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Mathematical Physics (math-ph)
subject: Analysis of PDEs (math.AP)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We study the singularity formation of smooth solutions of the relativistic Euler equations in $(3+1)$-dimensional spacetime for both finite initial energy and infinite initial energy. For the finite initial energy case, we prove that any smooth solution, with compactly supported non-trivial initial data, blows up in finite time. For the case of infinite initial energy, we first prove the existence, uniqueness and stability of a smooth solution if the initial data is in the subluminal region away from the vacuum. By further assuming the initial data is a smooth compactly supported perturbation around a non-vacuum constant background, we prove the property of finite propagation speed of such a perturbation. The smooth solution is shown to blow up in finite time provided that the radial component of the initial "generalized" momentum is sufficiently large.
description: 30 pages
Role of Third Lady in W.A. Mozart’s "Die Zauberflöte"
Creators: name: Wood, Heidi Christine
Publisher: name: University of British Columbia
Year: 2009

description: The thesis for the Master of Music degree in Opera Performance consists of the performance of a major role in one full opera production in the first or second year. I performed the role of Third Lady in Mozart's "Zauberflöte" on December 12th and 14th, 2003.
Mobile Robot Path Planning in Dynamic Environments: A Survey
Creators: name: Cai, Kuanqi
name: Wang, Chaoqun
name: Cheng, Jiyu
name: De Silva, Clarence W
name: Meng, Max Q. -H.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: There are many challenges for robot navigation in densely populated dynamic environments. This paper presents a survey of the path planning methods for robot navigation in dense environments. Particularly, the path planning in the navigation framework of mobile robots is composed of global path planning and local path planning, with regard to the planning scope and the executability. Within this framework, the recent progress of the path planning methods is presented in the paper, while examining their strengths and weaknesses. Notably, the recently developed Velocity Obstacle method and its variants that serve as the local planner are analyzed comprehensively. Moreover, as a model-free method that is widely used in current robot applications, the reinforcement learning-based path planning algorithms are detailed in this paper.
Unitarily localizable entanglement of Gaussian states
Creators: name: Serafini, Alessio
name: Adesso, Gerardo
name: Illuminati, Fabrizio
Publisher: name: arXiv
Year: 2004
Subjects: subject: Quantum Physics (quant-ph)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We consider generic $m\times n$-mode bipartitions of continuous variable systems, and study the associated bisymmetric multimode Gaussian states. They are defined as $(m+n)$-mode Gaussian states invariant under local mode permutations on the $m$-mode and $n$-mode subsystems. We prove that such states are equivalent, under local unitary transformations, to the tensor product of a two-mode state and of $m+n-2$ uncorrelated single-mode states. The entanglement between the $m$-mode and the $n$-mode blocks can then be completely concentrated on a single pair of modes by means of local unitary operations alone. This result allows to prove that the PPT (positivity of the partial transpose) condition is necessary and sufficient for the separability of $(m + n)$-mode bisymmetric Gaussian states. We determine exactly their negativity and identify a subset of bisymmetric states whose multimode entanglement of formation can be computed analytically. We consider explicit examples of pure and mixed bisymmetric states and study their entanglement scaling with the number of modes.
description: 10 pages, 2 figures
Peer Effect, Risk-Pooling and Status Seeking: Which Matters to Gift Spending Escalation in Rural China?
Creators: name: Chen, Xi
name: Zhang, Xiaobo
name: Chen, Xi
name: Zhang, Xiaobo
Publisher: name: Unknown
Year: 2011
Subjects: subject: Agricultural and Food Policy
subject: Agricultural Finance
subject: Community/Rural/Urban Development
subject: Consumer/Household Economics
subject: Demand and Price Analysis
subject: Food Consumption/Nutrition/Food Safety
subject: Food Security and Poverty
subject: Institutional and Behavioral Economics
subject: International Development
subject: Public Economics
subject: Research Methods/ Statistical Methods
subject: Risk and Uncertainty
subject: Social Network
subject: Peer Effect
subject: Risk-pooling
subject: Status Seeking
subject: Gift-giving
subject: Ceremony

description: It has been widely documented that the poor spend a significant proportion of their income on gifts even at the expense of basic consumption. We test three competing explanations to this phenomenon, peer effect, status concern, and risk-pooling, based on a census-type primary household survey in three natural villages in rural China and detailed household records of gifts received in major occasions. The gift giving behavior is largely influenced by peers in the reference groups. Status concern is another key motive for “keeping up with the Joneses” in extending gifts. In particular, the poor with sons spend more on gift giving in proportion to their income than their rich counterparts in response to the tightening marriage market. In contrast, risk pooling does not seem to be a key driver of the observed gift giving patterns. Large windfall income to a large extent triggers the escalation of gift giving behavior.
description: This paper is based on our ongoing joint work with Ravi Kanbur. Xi Chen is grateful to Ravi Kanbur for invaluable comments, guidance and encouragement. For comments and suggestions, please direct correspondence to Xi Chen at xc49@cornell.edu.
description: Replaced with revised version of paper 07/22/11.
Anatomy of Stigmatized Behavior: Peer Influence and Relative Concern
Creators: name: Chen, Xi
name: Chen, Xi
Publisher: name: Unknown
Year: 2011
Subjects: subject: Agricultural and Food Policy
subject: Community/Rural/Urban Development
subject: Consumer/Household Economics
subject: Food Security and Poverty
subject: Health Economics and Policy
subject: Institutional and Behavioral Economics
subject: International Development
subject: Labor and Human Capital
subject: Research Methods/ Statistical Methods
subject: Risk and Uncertainty
subject: Social Stigma
subject: Peer Influences
subject: Relative Concern
subject: Blood Donation
subject: China

description: Despite the resultant disutility, some people, in particular the poor, are still engaged in behavior carrying social stigma, such as selling organs and sex. Empirical economic studies on stigmatized behavior are largely absent due to lack of data. In this paper, merging a unique long-term gift exchange record with a census-type panel survey over three waves in rural China, we examine blood sales (or more correctly, “donations with nutrition subsidy”), a widely regarded stigma behavior in the Chinese society. Three identification strategies are applied to identify peer influence, namely conventional IV method, centrality-based reweighting and spatial instruments strategy. Results show that a 100% rise in peers’ engagement in blood sales increases one’s sales probability by 12%-21%, sales value by 9%-12%, and a second household member selling blood by 9%-16%. The results are robust to adding heterogeneous intensities of social ties and definitions of reference groups. Moreover, concern for status plays an important role in shaping stigma behavior, especially when the consequence of falling behind is grave. For example, families with unmarried son are more likely to sale blood as they need to build bigger houses, bid up bride price, and throw larger wedding banquet in order to improve their sons’ likelihood of marriage in the increasingly tightening marriage market. However, status concern is not captured by the conventional community-specific inequality measures. Our results call for a big caution using the well-accepted Gini index in predicting social behavior, and special attention should be given to the negative externality originated from peers’ stigmatized behavior.
description: This paper is based on an ongoing joint work with David Sahn and Xiaobo Zhang.