cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Three Dimensional Topological Field Theory induced from Generalized Complex Structure
Creators: name: Ikeda, Noriaki
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Differential Geometry (math.DG)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We construct a three-dimensional topological sigma model which is induced from a generalized complex structure on a target generalized complex manifold. This model is constructed from maps from a three-dimensional manifold $X$ to an arbitrary generalized complex manifold $M$. The theory is invariant under the diffeomorphism on the world volume and the $b$-transformation on the generalized complex structure. Moreover the model is manifestly invariant under the mirror symmetry. We derive from this model the Zucchini's two dimensional topological sigma model with a generalized complex structure as a boundary action on $\partial X$. As a special case, we obtain three dimensional realization of a WZ-Poisson manifold.
description: 18 pages
Measuring the Requirements and Benefits of Productivity Maintenance Research
Creators: name: Blakeslee, Leroy L.
name: Blakeslee, Leroy L.
Publisher: name: Unknown
Year: 1987
Subjects: Productivity Analysis
Research and Development/Tech Change/Emerging Technologies

description: Though the case for maintaining the even increasing agricultural resource productivity seems quite clear, the definition of maintenance research seems to be less so. I will proceed with an examination of what maintenance research is perceived to be, and how it is to be differentiated from non-maintenance research. Some evidence on the scope and nature of maintenance research activities will then be considered. Next, I will present some results from attempts to estimate structures formulated specifically to quantify the processes involved. The paper then concludes with some observations about possibilities for future work.
Characterization of Dielectric Materials by Sparse Signal Processing with Iterative Dictionary Updates
Creators: name: Thanthrige, Udaya S. K. P. Miriya
name: Barowski, Jan
name: Rolfes, Ilona
name: Erni, Daniel
name: Kaiser, Thomas
name: Sezgin, Aydin
Publisher: name: arXiv
Year: 2020
Subjects: subject: Signal Processing (eess.SP)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Estimating parameters and properties of various materials without causing damage to the material under test (MUT) is important in many applications. Thus, in this letter, we address this by wireless sensing. Here, the accuracy of the estimation depends on the accurate estimation of the properties of the reflected signal from the MUT (e.g., number of reflections, their amplitudes and time delays). For a layered MUT, there are multiple reflections and, due to the limited bandwidth at the receiver, these reflections superimpose each other. Since the number of reflections coming from the MUT is limited, we propose sparse signal processing (SSP) to decompose the reflected signal. In SSP, a so called dictionary is required to obtain a sparse representation of the signal. Here, instead of a fixed dictionary, a dictionary update technique is proposed to improve the estimation of the reflected signal. To validate the proposed method, a vector network analyzer (VNA) based measurement setup is used. It turns out that the estimated dielectric constants are in close agreement with the dielectric constants of the MUTs reported in literature. Further, the proposed approach outperforms the state-of-the-art model-based curve-fitting approach in thickness estimation.
description: 5 Pages, Accepted in IEEE Sensor Letters, Sept. 2020
E and B modes of the CMB y-type distortions: polarised kinetic Sunyaev-Zeldovich effect from the reionisation and post-reionisation eras
Creators: name: Gon, Aritra Kumar
name: Khatri, Rishi
Publisher: name: arXiv
Year: 2022
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We study the E and B mode polarisation of the cosmic microwave background (CMB) originating from the transverse peculiar velocity of free electrons, at second order in perturbation theory, during the reionisation and post-reionisation eras. Interestingly, the spectrum of this polarised kinetic Sunyaev-Zeldovich (SZ) effect can be decomposed into a blackbody part and a y-type distortion. The y-distortion part is distinguishable from the primary E and B modes and also the lensing B modes. Furthermore, it is also differentiable from the other y-type signals, such as the thermal SZ effect, which are unpolarised. We show that this signal is sensitive to the reionisation history, in particular to how fast reionisation happens. The E and B modes of y-type distortion provide a way to beat the cosmic variance of primary CMB anisotropies and are an independent probe of the cosmological parameters. The blackbody component of the pkSZ effect would be an important foreground for the primordial tensor modes for tensor to scalar ratio $r \lesssim 3\times10^{-5}$.
description: Published on JCAP
The Agricultural Knowledge Production Function: An Empirical Look
Creators: name: Pardey, Philip G.
name: Pardey, Philip G.
Publisher: name: Unknown
Year: 1987
Subjects: Productivity Analysis
Research and Development/Tech Change/Emerging Technologies

description: Economic analysis of the process of technical change has often involved macro-level studies of its causes and consequences. Relatively little attention has been given to the, more fundamental knowledge generation process itself. This stems in large part from the real difficulties of obtaining appropriate indicators of research output. The view that there exists a systematic relationship between research expenditures and knowledge increments has been taken up by numerous authors including Evenson (1968), Minasian (1969), Pakes (1978), Gri1iches (1979), and Kamien and Schwartz (1982). It follows naturally from the perception that, in general, science progresses by a sequence of marginal improvements rather than a series of discrete and essentially sporadic breakthroughs (see Burke [1978). Recent studies by Pakes and Gri1iches (1980), Hausman et a1. (1981), and Hall et a1. (1984) have sought direct estimates of the research input-output relationship for research performed by private firms in the non-agricultural sector. To date there appears to be no similar analysis of the public sector agricultural research process. The study reported here represents a first step in this direction. It develops some quantifiable indicators of agricultural knowledge production by the U.S. public sector research system and will also attempt to provide some clues as to the nature of the agricultural research spending-research output relationship.
The EXOTIME project: Signals in the $ O-C $ diagrams of the rapidly pulsating subdwarfs DW Lyn, V1636 Ori, QQ Vir, and V541 Hya
Creators: name: Mackebrandt, F.
name: Schuh, S.
name: Silvotti, R.
name: Kim, S. -L.
name: Kilkenny, D.
name: Green, E. M.
name: Lutz, R.
name: Nagel, T.
name: Provencal, J. L.
name: Otani, T.
name: Oswalt, T. D.
name: Benatti, S.
name: Lanteri, L.
name: Bonanno, A.
name: Frasca, A.
name: Janulis, R.
name: Paparó, M.
name: Molnár, L.
name: Claudi, R.
name: Østensen, R. H.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We aim to investigate variations in the arrival time of coherent stellar pulsations due to the light-travel time effect to test for the presence of sub-stellar companions. Those companions are the key to one possible formation scenario of apparently single sub-dwarf B stars. We made use of an extensive set of ground-based observations of the four large amplitude p-mode pulsators DW Lyn, V1636 Ori, QQ Vir, and V541 Hya. Observations of the TESS space telescope are available on two of the targets. The timing method compares the phase of sinusoidal fits to the full multi-epoch light curves with phases from the fit of a number of subsets of the original time series. Observations of the TESS mission do not sample the pulsations well enough to be useful due to the (currently) fixed two-minute cadence. From the ground-based observations, we infer evolutionary parameters from the arrival times. The residual signals show many statistically significant periodic signals, but no clear evidence for changes in arrival time induced by sub-stellar companions. The signals can be explained partly by mode beating effects. We derive upper limits on companion masses set by the observational campaign.
description: 22 pages, 23 figures, accepted for publication in A&A
Distribution of Agricultural Research Impacts
Creators: name: White, Fred C.
name: White, Fred C.
Publisher: name: Unknown
Year: 1987
Subjects: Research and Development/Tech Change/Emerging Technologies

description: When there is a correspondence between two logical systems, duality can be used to derive a correspondence between results in one system and results in another system (Russell and Wilkinson, 1978). Under appropriate regularity conditions, dual functions such as normalized profit functions in production economics embody the same information on technology as the more familiar primal production functions. The technology can be examined directly using the primal approach or indirectly using the dual approach. It is often easier to estimate product supply and input demand relationships using a dual approach, because only endogenous variables appear on the left-hand side of equations and only exogenous variables appear on the right-hand side of equations (Shumway, 1983). Duality concepts allow the estimation of output supply and input demand functions that are consistent with underlying economic theory (Shumway, 1986). Estimation generally requires that the equations be estimated as a system in order to account for relevant cross-equation restrictions. Regularity conditions related to homogeneity, symmetry, and curvature properties required to ensure that a profit-maximizing solution exists can be maintained through appropriate restrictions or tested. Considering the versatility and power of the duality approach, one would conclude that empirical estimates using this approach might be better in some sense than estimates from other models that were not consistent with economic theory. The purpose of this paper is to review empirical estimates related to technological change in U.S. agriculture that have been obtained using the duality approach. Both static and dynamic duality models will be considered, although there is only limited empirical evidence on technological change using the dynamic duality approach.
SETI and Democracy
Creators: name: Hatfield, Peter
name: Trueblood, Leah
Publisher: name: arXiv
Year: 2020
Subjects: subject: Popular Physics (physics.pop-ph)
subject: History and Philosophy of Physics (physics.hist-ph)
subject: FOS: Physical sciences

description: There is a wide-ranging debate about the merits and demerits of searching for, and sending messages to, extraterrestrial intelligences (SETI and METI). There is however reasonable (but not universal) consensus that replying to a message from an extraterrestrial intelligence should not be done unilaterally, without consultation with wider society and the rest of the world. But how should this consultation actually work? In this paper we discuss various ways that decision making in such a scenario could be done democratically, and gain legitimacy. In particular we consider a scientist-led response, a politician-led response, deciding a response using a referendum, and finally using citizens' assemblies. We present the results of a survey of a representative survey of 2,000 people in the UK on how they thought a response should best be determined, and finally discuss parallels to how the public is responding to scientific expertise in the COVID-19 Pandemic
description: 11 pages, 2 figures, accepted Acta Astronautica
A Model for Twin Kilohertz Quasi-Periodic Oscillations in Neutron Star Low-Mass X-Ray Binaries
Creators: name: Li, X. -D.
name: Zhang, C. -M.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We suggest a plausible interpretation for the twin kiloHertz quasi-periodic oscillations (kHz QPOs) in neutron star low-mass X-ray binaries. We identify the upper kHz QPO frequencies to be the rotational frequency and the lower kHz QPOs the standing kink modes of loop oscillations at the inner edge of the accretion disk, respectively. Taking into account the interaction between the neutron star magnetic field and the disk, this model naturally relates the twin QPO frequencies with the star's spin frequencies. We have applied the model to four X-ray sources with kHz QPOs detected simultaneously and known spin frequencies.
description: 12 pages including 3 figures, accepted for publication in ApJL
Visualizing the self : modernity, identity, and the Gente Decente in porfirian Mexico
Creators: name: Eineigel, Susanne
Publisher: name: University of British Columbia
Year: 2009

description: In late nineteenth-century Mexico City, members of an incipient middle class attempted to define themselves within new urban spaces and against a growing heterogeneous mix of strangers. This thesis argues that an increasingly visual culture brought about by urbanization and new visual practices heightened an awareness of the body's surface appearances and conduct. As a newly-emerging social group, members of the middle class needed to learn how to display and perform, as well as to read, the codes of class, gender, and citizenship. This paper analyzes two types of texts that provided their middle-class readers with guides both to self-fashioning and to navigating the complexities of a growing and rapidly changing city. Manuel Antonio Carrefio's popular Manual de Urbanidady Buenas Maneras taught its readers the rules of dress and behaviour that signaled respectability and the short urban sketches of writers such as Manuel Gutierrez Najera and Jose Thomas de Cuellar narrated the city's urban and social landscape into scenes of familiarity and recognition. However, despite attempts to stabilize codes of identification, these texts also reflect middle-class anxieties that surface appearances and social mobility could mask or disguise an individual's "immoral" character or lower-class background. The reading of these texts by members of the middle class formed part of larger late nineteenth-century discourses that attempted to mould a modern citizen through moral reform, education, and hygiene.
All-MgB2 Josephson tunnel junctions
Creators: name: Ueda, K.
name: Saito, S.
name: Semba, K.
name: Makimoto, T.
name: Naito, M.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Sandwich-type all-MgB2 Josephson tunnel junctions (MgB2/AlOx/MgB2) have been fabricated for the first time with as-grown MgB2 films formed by molecular beam epitaxy. The junctions exhibit substantial superconducting current (IcRN product ~ 0.8 mV at 4.2K), a well-defined superconducting gap (delta = ~2.3 mV), and clear Fraunhofer patterns. The superconducting gap voltage of delta agrees well with the smaller gap in the multi-gap scenario. The results demonstrate that MgB2 has great promise for superconducting electronics that can be operated at T ~ 20 K.
description: 9 pages, 3 figures
Research Bias Effects for Input and Output Decisions: An Application to U.S. Cash-Grain Farms
Creators: name: Huffman, Wallace E.
name: Huffman, Wallace E.
Publisher: name: Unknown
Year: 1987
Subjects: Crop Production/Industries
Research and Development/Tech Change/Emerging Technologies

description: Duality theory and static multi-product technology have been applied to analyze aggregate agricultural data by Shumway; Weaver; and McKay, Lawrence and Vlastuin. Several studies (e.g., Antle; Binswanger; and Lopez, 1985a) have indexed technology with a time trend, but no study has attempted to investigate the effects of agricultural research, extension, and education in the multiple-output dual static framework. The objectives of this paper are (i) to assess the bias effects in cash-grain farmers' production decisions caused by public agricultural research, public extension, and farmers' schooling and (ii) to present new estimates of the shadow values of agricultural research, extension, and schooling obtained from the static dual model of agricultural production. The model is fitted to data for 42 states, pooled over Agricultural Census years 1949-74, containing the cash-grain farm type. The organization is as follows: The econometric model of production is first presented. Second, the empirical analyses, which contain a discussion of the data and empirical results, are presented. Conclusions and implications are in the final section.
The PAX Toolkit and its Applications at Tevatron and LHC
Creators: name: Kappler, Steffen
name: Erdmann, Martin
name: Felzmann, Ulrich
name: Hirschbuehl, Dominic
name: Kirsch, Matthias
name: Quast, Guenter
name: Schmidt, Alexander
name: Weng, Joanna
Publisher: name: arXiv
Year: 2005
Subjects: subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences

description: At the CHEP03 conference we launched the Physics Analysis eXpert (PAX), a C++ toolkit released for the use in advanced high energy physics (HEP) analyses. This toolkit allows to define a level of abstraction beyond detector reconstruction by providing a general, persistent container model for HEP events. Physics objects such as particles, vertices and collisions can easily be stored, accessed and manipulated. Bookkeeping of relations between these objects (like decay trees, vertex and collision separation, etc.) including deep copies is fully provided by the relation management. Event container and associated objects represent a uniform interface for algorithms and facilitate the parallel development and evaluation of different physics interpretations of individual events. So-called analysis factories, which actively identify and distinguish different physics processes and study systematic uncertainties, can easily be realized with the PAX toolkit. PAX is officially released to experiments at Tevatron and LHC. Being explored by a growing user community, it is applied in a number of complex physics analyses, two of which are presented here. We report the successful application in studies of t-tbar production at the Tevatron and Higgs searches in the channel t-tbar-Higgs at the LHC and give a short outlook on further developments.
Object Detection Using Sim2Real Domain Randomization for Robotic Applications
Creators: name: Horváth, Dániel
name: Erdős, Gábor
name: Istenes, Zoltán
name: Horváth, Tomáš
name: Földi, Sándor
Publisher: name: arXiv
Year: 2022
Subjects: subject: Robotics (cs.RO)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Robots working in unstructured environments must be capable of sensing and interpreting their surroundings. One of the main obstacles of deep-learning-based models in the field of robotics is the lack of domain-specific labeled data for different industrial applications. In this article, we propose a sim2real transfer learning method based on domain randomization for object detection with which labeled synthetic datasets of arbitrary size and object types can be automatically generated. Subsequently, a state-of-the-art convolutional neural network, YOLOv4, is trained to detect the different types of industrial objects. With the proposed domain randomization method, we could shrink the reality gap to a satisfactory level, achieving 86.32% and 97.38% mAP50 scores, respectively, in the case of zero-shot and one-shot transfers, on our manually annotated dataset containing 190 real images. Our solution fits for industrial use as the data generation process takes less than 0.5 s per image and the training lasts only around 12 h, on a GeForce RTX 2080 Ti GPU. Furthermore, it can reliably differentiate similar classes of objects by having access to only one real image for training. To our best knowledge, this is the only work thus far satisfying these constraints.
description: Published in IEEE Transactions on Robotics (T-RO)
Quantum Singularities
Creators: name: Konkowski, D. A.
name: Helliwell, T. M.
name: Wieland, C.
Publisher: name: arXiv
Year: 2004
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The definitions of classical and quantum singularities in general relativity are reviewed. The occurence of quantum mechanical singularities in certain spherically symmetric and cylindrically symmetric (including infinite line mass)spacetimes is considered. A strong repulsive ``potential'' near the classical singularity is shown to turn a classically singular spacetime into a quantum mechanically nonsingular spacetime.
description: 5 pages, no figures, references current
Additional file 1 of The importance of social factors in the association between physical activity and depression in children
Creators: name: Conley, May I.
name: Hindley, Isabella
name: Baskin-Sommers, Arielle
name: Gee, Dylan G.
name: B. J. Casey
name: Rosenberg, Monica D.
Publisher: name: figshare
Year: 2020
Subjects: subject: Science Policy
subject: Cancer
subject: 111714 Mental Health
subject: FOS: Health sciences

description: Additional file 1: Section 1. Sex differences in relationship between social physical activities and depression. Section 2. Youth activities and other mental health symptoms. Section 3. Specificity analyses of mediation effects. Figure S1a. Line plot comparing total intra-cluster variation (total within sum of squares) to hypothetical number of clusters (k). Figure S1b. Line plot comparing average silhouette of observations for hypothetical number of clusters (k). Figure S2. Histogram of CBCL t-scores for subscale symptoms across original (n = 4,393) and replication samples (n = 7,127). Figure S3. Histogram of CBCL t-scores for broadband symptoms across original (n = 4,393) and replication samples (n = 7,127). Figure S4 Scatter plot of transformed depressive symptoms by participation in social–physical activities split by sex. A mixed effect model was used to examine the differences in symptoms according to activity participation in the past 12 months. Table S1a. Descriptive statistics for original sample internalizing t-scores across all activity categories. Table S1b. Descriptive statistics for replication sample internalizing t-scores across all activity categories. Table S2. Relationship between involvement in clusters of SAIQ activities on normalized CBCL internalizing subscale symptoms. All analyses include site and family nested within site as random effects. Table S3. Relationship between involvement in clusters of SAIQ activities on CBCL broadband symptoms (t-scores). All analyses include site and family nested within site as random effects.
Energy level displacement of excited np states of kaonic hydrogen
Creators: name: Ivanov, A. N.
name: Cargnelli, M.
name: Faber, M.
name: Fuhrmann, H.
name: Ivanova, V. A.
name: Marton, J.
name: Troitskaya, N. I.
name: Zmeskal, J.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We compute the energy level displacement of the excited np states of kaonic hydrogen within the quantum field theoretic and relativistic covariant model of strong low-energy bar-KN interactions suggested in EPJA21, 11 (2004). For the width of the energy level of the excited 2p state of kaonic hydrogen, caused by strong low-energy interactions, we find Gamma_2p = 2 meV. This result is important for the theoretical analysis of the X-ray yields in kaonic hydrogen.
description: 20 pages, no figures, Latex, new references are added
Training Gaussian Boson Sampling Distributions
Creators: name: Banchi, Leonardo
name: Quesada, Nicolás
name: Arrazola, Juan Miguel
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Gaussian Boson Sampling (GBS) is a near-term platform for photonic quantum computing. Applications have been developed which rely on directly programming GBS devices, but the ability to train and optimize circuits has been a key missing ingredient for developing new algorithms. In this work, we derive analytical gradient formulas for the GBS distribution, which can be used to train devices using standard methods based on gradient descent. We introduce a parametrization of the distribution that allows the gradient to be estimated by sampling from the same device that is being optimized. In the case of training using a Kullback-Leibler divergence or log-likelihood cost function, we show that gradients can be computed classically, leading to fast training. We illustrate these results with numerical experiments in stochastic optimization and unsupervised learning. As a particular example, we introduce the variational Ising solver, a hybrid algorithm for training GBS devices to sample ground states of a classical Ising model with high probability.
description: 15 pages, 3 figures
The role of stationarity in magnetic crackling noise
Creators: name: Durin, Gianfranco
name: Zapperi, Stefano
Publisher: name: arXiv
Year: 2005
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We discuss the effect of the stationarity on the avalanche statistics of Barkhuasen noise signals. We perform experimental measurements on a Fe$_{85}$B$_{15}$ amorphous ribbon and compare the avalanche distributions measured around the coercive field, where the signal is stationary, with those sampled through the entire hysteresis loop. In the first case, we recover the scaling exponents commonly observed in other amorphous materials ($τ=1.3$, $α=1.5$). while in the second the exponents are significantly larger ($τ=1.7$, $α=2.2$). We provide a quantitative explanation of the experimental results through a model for the depinning of a ferromagnetic domain wall. The present analysis shed light on the unusually high values for the Barkhausen noise exponents measured by Spasojevic et al. [Phys. Rev. E 54 2531 (1996)].
description: submitted to JSTAT. 11 pages 5 figures
Additional file 1 of Bioproduction of succinic acid from xylose by engineered Yarrowia lipolytica without pH control
Creators: name: Prabhu, Ashish A.
name: Ledesma-Amaro, Rodrigo
name: Lin, Carol Sze Ki
name: Coulon, Frederic
name: Thakur, Vijay Kumar
name: Kumar, Vinod
Publisher: name: figshare
Year: 2020
Subjects: subject: Biochemistry
subject: Space Science
subject: Medicine
subject: Microbiology
subject: FOS: Biological sciences
subject: Genetics
subject: Molecular Biology
subject: Pharmacology
subject: Biotechnology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: 69999 Biological Sciences not elsewhere classified
subject: Developmental Biology
subject: Inorganic Chemistry

description: Additional file 1: Table S1. Primers used in this study. Table S2. List of Plasmids and strain used in this study.
Food Security, Energy Equity, and the Global Commons: a Computable Village Model applied to sub-Saharan Africa
Creators: name: Winter, Etti Maria
name: Fasse, Anja
name: Winter, Etti Maria
name: Fasse, Anja
Publisher: name: Unknown
Year: 2009
Subjects: Crop Production/Industries
Productivity Analysis

description: This paper examines potential of contract farming as a rural development tool by revealing its effect on productivity and income of small holders in tea production in north-western Vietnam. In the present research, three economic analyses are applied. First, the technical efficiency of tea production is estimated by using stochastic frontier model. The results show that contract farming achieved significantly higher technical efficiency compared to non-contract farming. Second, logit model is investigated to determine the influential socio-economic characteristics of households for contract participation. The model indicates that social relationship of households, such as the membership in the communist party, play an important role in contract participation with 73% correct prediction. Finally, the impact of contract participation on income is estimated by applying Propensity Score Matching. A significant effect of contract participation on income by 8,000 VND daily per capita can be observed.
Chern Insulators and Topological Flat-bands in Magic-angle Twisted Bilayer Graphene
Creators: name: Wu, Shuang
name: Zhang, Zhenyuan
name: Watanabe, K.
name: Taniguchi, T.
name: Andrei, Eva Y.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Magic-angle twisted bilayer graphene (MA-TBG) exhibits intriguing quantum phase transitions triggered by enhanced electron-electron interactions when its flat-bands are partially filled. However, the phases themselves and their connection to the putative non-trivial topology of the flat bands are largely unexplored. Here we report transport measurements revealing a succession of doping-induced Lifshitz transitions that are accompanied by van Hove singularities (VHS) which facilitate the emergence of correlation-induced gaps and topologically non-trivial sub-bands. In the presence of a magnetic field, well quantized Hall plateaus at filling of 1, 2, 3 carriers per moiré-cell reveal the sub-band topology and signal the emergence of Chern insulators with Chern-numbers, ! = !, !, !, respectively. Surprisingly, for magnetic fields exceeding 5T we observe a VHS at a filling of 3.5, suggesting the possibility of a fractional Chern insulator. This VHS is accompanied by a crossover from low-temperature metallic, to high-temperature insulating behavior, characteristic of entropically driven Pomeranchuk-like transitions,
description: 29 pages, 15 figures
Performance of Hamamatsu 64-anode photomultipliers for use with wavelength--shifting optical fibres
Creators: name: Tagg, N.
name: De Santo, A.
name: Weber, A.
name: Cabrera, A.
name: Miyagawa, P. S.
name: Barker, M. A.
name: Lang, K.
name: Michael, D.
name: Saakyan, R.
name: Thomas, J.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: Hamamatsu R5900-00-M64 and R7600-00-M64 photomultiplier tubes will be used with wavelength--shifting optical fibres to read out scintillator strips in the MINOS near detector. We report on measurements of the gain, efficiency, linearity, crosstalk, and dark noise of 232 of these PMTs, of which 219 met MINOS requirements.
description: 15 pages, 12 figures. Accepted by Nucl. Inst. Meth. A
Does Composition of Government Spending Matter to Economic Growth?
Creators: name: Yu, Bingxin
name: Fan, Shenggen
name: Saurkar, Anuja
name: Yu, Bingxin
name: Fan, Shenggen
name: Saurkar, Anuja
Publisher: name: Unknown
Year: 2009
Subjects: subject: Agricultural and Food Policy
subject: Financial Economics
subject: International Development
subject: Government expenditure
subject: growth
subject: GMM

description: This paper assesses the impact of the composition of government spending on economic growth in developing countries. We use a dynamic GMM model and a panel data set for 44 developing countries between 1980 and 2004. We find that the various types of government spending have different impact on economic growth. In Africa, human capital spending contributes to economic growth whereas in Asia, capital formation, agriculture and education has strong growth promoting effect. In Latin America, none of government spending items has significant impact on economic growth. Our results are robust regardless of model specifications and instruments chosen.
Self-assembled nanowires on semiconductor surfaces
Creators: name: Owen, J. H. G.
name: Miki, K.
name: Bowler, D. R.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: A number of different families of nanowires which self-assemble on semiconductor surfaces have been identified in recent years. They are particularly interesting from the standpoint of nanoelectronics, which seeks non-lithographic ways of creating interconnects at the nanometre scale (though possibly for carrying signal rather than current), as well as from the standpoint of traditional materials science and surface science. We survey these families and consider their physical and electronic structure, as well as their formation and reactivity. Particular attention is paid to rare earth nanowires and the Bi nanoline, both of which self-assemble on Si(001).
description: 32 pages, 30 figures
Additional file 2 of Estimating the daily trend in the size of the COVID-19 infected population in Wuhan
Creators: name: Lin, Qiu-Shi
name: Tao-Jun Hu
name: Zhou, Xiao-Hua
Publisher: name: figshare
Year: 2020
Subjects: subject: Medicine
subject: Neuroscience
subject: Biotechnology
subject: 19999 Mathematical Sciences not elsewhere classified
subject: FOS: Mathematics
subject: Cancer
subject: 110309 Infectious Diseases
subject: FOS: Health sciences
subject: Computational Biology

description: Additional file 2. The second file’s name is Appendix.docx. It contains two appendices with additional sensitivity analysis and detailed description of our method. They are only for reviewers’ convenience, not for publication.
Valley polarization of singlet and triplet trions in WS$_2$ monolayer in magnetic fields
Creators: name: Kapuściński, P.
name: Vaclavkova, D.
name: Grzeszczyk, M.
name: Slobodeniuk, A. O.
name: Nogajewski, K.
name: Bartos, M.
name: Watanabe, K.
name: Taniguchi, T.
name: Faugeras, C.
name: Babiński, A.
name: Potemski, M.
name: Molas, M. R.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The spectral signatures associated with different negatively charged exciton complexes (trions) in a WS$_2$ monolayer encapsulated in hBN, are analyzed from low temperature and polarization resolved reflectance contrast (RC) and photoluminescence (PL) experiments, with an applied magnetic field. Based on results obtained from the RC experiment, we show that the valley Zeeman effect affects the optical response of both the singlet and the triplet trion species through the evolution of their energy and of their relative intensity, when applying an external magnetic field. Our analysis allows us to estimate a free electron concentration of $\sim 1.3 \cdot 10^{11}$ cm$^{-2}$. The observed evolutions based on PL experiments on the same sample are different and can hardly be understood within the same simple frame highlighting the complexity of relaxation processes involved in the PL response.
description: 7 pages, 4 figures; source file corrected
Testing Distributions of Huge Objects
Creators: name: Goldreich, Oded
name: Ron, Dana
Publisher: name: arXiv
Year: 2022
Subjects: subject: Data Structures and Algorithms (cs.DS)
subject: FOS: Computer and information sciences

description: We initiate a study of a new model of property testing that is a hybrid of testing properties of distributions and testing properties of strings. Specifically, the new model refers to testing properties of distributions, but these are distributions over huge objects (i.e., very long strings). Accordingly, the model accounts for the total number of local probes into these objects (resp., queries to the strings) as well as for the distance between objects (resp., strings), and the distance between distributions is defined as the earth mover's distance with respect to the relative Hamming distance between strings.
 We study the query complexity of testing in this new model, focusing on three directions. First, we try to relate the query complexity of testing properties in the new model to the sample complexity of testing these properties in the standard distribution testing model. Second, we consider the complexity of testing properties that arise naturally in the new model (e.g., distributions that capture random variations of fixed strings). Third, we consider the complexity of testing properties that were extensively studied in the standard distribution testing model: Two such cases are uniform distributions and pairs of identical distributions.
MFRNet: A New CNN Architecture for Post-Processing and In-loop Filtering
Creators: name: Ma, Di
name: Zhang, Fan
name: Bull, David R.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Image and Video Processing (eess.IV)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: Multimedia (cs.MM)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: In this paper, we propose a novel convolutional neural network (CNN) architecture, MFRNet, for post-processing (PP) and in-loop filtering (ILF) in the context of video compression. This network consists of four Multi-level Feature review Residual dense Blocks (MFRBs), which are connected using a cascading structure. Each MFRB extracts features from multiple convolutional layers using dense connections and a multi-level residual learning structure. In order to further improve information flow between these blocks, each of them also reuses high dimensional features from the previous MFRB. This network has been integrated into PP and ILF coding modules for both HEVC (HM 16.20) and VVC (VTM 7.0), and fully evaluated under the JVET Common Test Conditions using the Random Access configuration. The experimental results show significant and consistent coding gains over both anchor codecs (HEVC HM and VVC VTM) and also over other existing CNN-based PP/ILF approaches based on Bjontegaard Delta measurements using both PSNR and VMAF for quality assessment. When MFRNet is integrated into HM 16.20, gains up to 16.0% (BD-rate VMAF) are demonstrated for ILF, and up to 21.0% (BD-rate VMAF) for PP. The respective gains for VTM 7.0 are up to 5.1% for ILF and up to 7.1% for PP.
Determinants of Agricultural Cash Rents in Germany: A Spatial Econometric Analysis for Farm-Level Data
Creators: name: Breustedt, Gunnar
name: Habermann, Hendrik
name: Breustedt, Gunnar
name: Habermann, Hendrik
Publisher: name: Unknown
Year: 2009
Subjects: subject: Farm Management
subject: Land Economics/Use
subject: Political Economy
subject: farmland rental price
subject: per-hectare premium
subject: spatial econometrics
subject: subsidy incidence

description: This article analyses determinants for 2001 farmland rental prices from 4376 farms in Germany. We derive our regression equation from a spatial reaction function to allow for spatial transmission of rental prices. Results from a general spatial model show that a € 1 per hectare higher rental price in a farmer’s neighbourhood coincides with a € 0.57 higher rental price he has to pay. For policy evaluation we estimate the marginal incidence of regional EU per-hectare premiums. We find a value significantly above one and propose an explanation for this counterintuitive result based on the long-running nature of rental contracts, simultaneity of premium introduction and intervention price cuts as well as assumed stickiness of rental prices. Regional livestock density, which is indirectly influenced by different policies, is also a major determinant of rental prices.
Characterization of Optical Light Curves of Extreme Variability Quasars Over a ~16-yr Baseline
Creators: name: Luo, Yuanze
name: Shen, Yue
name: Yang, Qian
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We study the optical light curves - primarily probing the variable emission from the accretion disk - of ~ 900 extreme variability quasars (EVQs, with maximum flux variations more than 1 mag) over an observed-frame baseline of ~ 16 years using public data from the SDSS Stripe 82, PanSTARRS-1 and the Dark Energy Survey. We classify the multi-year long-term light curves of EVQs into three categories roughly in the order of decreasing smoothness: monotonic decreasing or increasing (3.7%), single broad peak and dip (56.8%), and more complex patterns (39.5%). The rareness of monotonic cases suggests that the major mechanisms driving the extreme optical variability do not operate over timescales much longer than a few years. Simulated light curves with a damped random walk model generally under-predict the first two categories with smoother long-term trends. Despite the different long-term behaviors of these EVQs, there is little dependence of the long-term trend on the physical properties of quasars, such as their luminosity, BH mass, and Eddington ratio. The large dynamic range of optical flux variability over multi-year timescales of these EVQs allows us to explore the ensemble correlation between the short-term (< 6 months) variability and the seasonal-average flux across the decade-long baseline (the rms-mean flux relation). We find that unlike the results for X-ray variability studies, the linear short-term flux variations do not scale with the seasonal-average flux, indicating different mechanisms that drive the short-term flickering and long-term extreme variability of accretion disk emission. Finally, we present a sample of 16 EVQs, where the approximately bell-shaped large amplitude variation in the light curve can be reasonably well fit by a simple microlensing model.
The role of strong electronic correlations in the metal-to-insulator transition in disordered LiAl_yTi_(2-y)O_4
Creators: name: Fazileh, F.
name: Gooding, R. J.
name: Atkinson, W. A.
name: Johnston, D. C.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The compound LiAl_yTi_(2-y)O_4 undergoes a metal-to-insulator transition for y_c ~0 .33. This system, in the absence of strong electronic correlations, is a prototypical example of quantum site percolation. However, it is known that the effects of disorder produced by such a percolating lattice are insufficient to explain this transition: a quantum site percolation model predicts y_c ~ 0.8, well above the experimental value. We have included an on-site Hubbard interaction into a model of this compound, using a real-space Hartree-Fock approach, and have found that for a Hubbard energy equal to 1.5 times the non-interacting bandwidth one obtains y_c~0.35. Further, as a function of increasing Hubbard energy, we find that an Altshuler-Aronov suppression of the density of states, delta N(E) ~ sqrt(| E-E_F |), reduces the density of states at the Fermi energy to zero at the critical Hubbard interaction. Using this ratio of correlation to hopping energy one is led to a prediction for the value of near-neighbour superexchange J/t~1/3 which is similar to that for the cuprate superconductors.
description: 10 pages, 4 figures
Universal and dynamic ridge filter for pencil beam scanning particle therapy: novel concept for ultra-fast treatment delivery
Creators: name: Maradia, Vivek
name: Colizzi, Isabella
name: Meer, David
name: Weber, Damien Charles
name: Lomax, Antony John
name: Actis, Oxana
name: Psoroulas, Serena
Publisher: name: arXiv
Year: 2022
Subjects: subject: Medical Physics (physics.med-ph)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: Purpose In PBS particle therapy, short treatment delivery time is paramount for the efficient treatment of moving targets with motion mitigation techniques (such as breath-hold, rescanning, and gating). Energy and spot position change time are limiting factors in reducing treatment time. In this study, we designed a universal and dynamic energy modulator (ridge filter, RF) to broaden the Bragg peak, to reduce the number of energies and spots required to cover the target volume, thus lowering the treatment time. Methods Our RF unit comprises two identical RFs placed just before the isocenter. Both RFs move relative to each other, changing the Bragg peaks characteristics dynamically. We simulated different Bragg peak shapes with the RF in TOPAS and validated them experimentally. We then delivered single-field plans with 1Gy/fraction to different geometrical targets in water, to measure the dose delivery time using the RF and compare it with the clinical settings. Results Aligning the RFs in different positions produces different broadening in the Bragg peak; we achieved a maximum broadening of 2 cm. With RF we reduced the number of energies in a field by more than 60%, and the dose delivery time by 50%, for all geometrical targets investigated, without compromising the dose distribution transverse and distal fall-off. Conclusions Our novel universal and dynamic RF allows for the adaptation of the Bragg peak broadening for a spot and/or energy layer based on the requirement of dose shaping in the target volume. It significantly reduces the number of energy layers and spots to cover the target volume, and thus the treatment time. This RF design is ideal for ultra-fast treatment delivery within a single breath-hold (5-10 sec), efficient delivery of motion mitigation techniques, and small animal irradiation with ultra-high dose rates (FLASH).
description: 18 pages, 9 figures
Angle-Constrained Formation Control for Circular Mobile Robots
Creators: name: Chan, Nelson P. K.
name: Jayawardhana, Bayu
name: de Marina, Hector Garcia
Publisher: name: arXiv
Year: 2020
Subjects: subject: Systems and Control (eess.SY)
subject: Multiagent Systems (cs.MA)
subject: Robotics (cs.RO)
subject: Optimization and Control (math.OC)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences
subject: FOS: Mathematics
subject: 34H05, 70E60, 93C10, 93C85

description: In this letter, we investigate the formation control problem of mobile robots moving in the plane where, instead of assuming robots to be simple points, each robot is assumed to have the form of a disk with equal radius. Based on interior angle measurements of the neighboring robots' disk, which can be obtained from low-cost vision sensors, we propose a gradient-based distributed control law and show the exponential convergence property of the associated error system. By construction, the proposed control law has the appealing property of ensuring collision avoidance between neighboring robots. We also present simulation results for {a team} of four circular mobile robots forming a rectangular shape.
description: 6 pages, submitted to the 59th IEEE Conf. Dec. Control and IEEE Control Systems Letters