cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Evolution of a foreshock bubble in the midtail (2020)
Creators: name: XUEYI WANG
name: CHIH-PING WANG
Publisher: name: figshare
Year: 2020
Subjects: subject: Geophysics
subject: FOS: Earth and related environmental sciences
subject: Space Science
subject: Plasma Physics

description: Partial data and figures for paper " Evolution of a foreshock bubble in the midtail foreshock and impact on the magnetopause: 3D global hybrid simulation" by Chih-Ping Wang et al.(2020). You could contact @ wangxue@auburn.edu to get more data.
Human Mobility Trends during the COVID-19 Pandemic in the United States
Creators: name: Lee, Minha
name: Zhao, Jun
name: Sun, Qianqian
name: Pan, Yixuan
name: Zhou, Weiyi
name: Xiong, Chenfeng
name: Zhang, Lei
Publisher: name: arXiv
Year: 2020
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Populations and Evolution (q-bio.PE)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: In March of this year, COVID-19 was declared a pandemic and it continues to threaten public health. This global health crisis imposes limitations on daily movements, which have deteriorated every sector in our society. Understanding public reactions to the virus and the non-pharmaceutical interventions should be of great help to fight COVID-19 in a strategic way. We aim to provide tangible evidence of the human mobility trends by comparing the day-by-day variations across the U.S. Large-scale public mobility at an aggregated level is observed by leveraging mobile device location data and the measures related to social distancing. Our study captures spatial and temporal heterogeneity as well as the sociodemographic variations regarding the pandemic propagation and the non-pharmaceutical interventions. All mobility metrics adapted capture decreased public movements after the national emergency declaration. The population staying home has increased in all states and becomes more stable after the stay-at-home order with a smaller range of fluctuation. There exists overall mobility heterogeneity between the income or population density groups. The public had been taking active responses, voluntarily staying home more, to the in-state confirmed cases while the stay-at-home orders stabilize the variations. The study suggests that the public mobility trends conform with the government message urging to stay home. We anticipate our data-driven analysis offers integrated perspectives and serves as evidence to raise public awareness and, consequently, reinforce the importance of social distancing while assisting policymakers.
description: 11 pages, 9 figures
Brésil: métissage et diversité
Creators: name: FILHO, HENRIQUE VIEIRA
Publisher: name: Zenodo
Year: 2016
Subjects: fotografia, arte, sociologia, diversidade, miscigenação, Brasil,fotopsicoterapia, photographie, art, sociologie, diversité, métissage, Brésil, photopsychothérapie

description: Henrique Vieira Filho est un photographe, designer et artiste numérique, mais aussi thérapeute holistique et cette une particularité influence directement son ouvre, qui cherche à illustrer la transcendance de l'être. Il travaille en collaboration avec les plus divers moyens de communication et est l’auteur de nombreux livres sur la Thérapie. La photographie est une passion et sert de base fondamentale pour toutes ses autres activités artistiques. Dans mon projet, le biotype ethnique de chaque individu, bien s’il peut avoir une origine prédominante, ne nie jamais le métissage de notre peuple et ne le limite jamais dans sa vision du monde. Henrique Vieira Filho é Fotógrafo, Designer e Artista Digital, além de Terapeuta Holístico, particularidade esta que influencia diretamente sua obra, que ilustra a transcendência do ser. Colaborador junto aos mais diversos meios de comunicação, autor de inúmeros livros relacionados à Terapia, tem a Fotografia como paixão e base fundamental para todos os seus demais desenvolvimentos artísticos. Em meu projeto, o biotipo étnico de cada indivíduo, ainda que possa predominar em uma direção, jamais nega a miscigenação de nosso povo e nunca limitará em sua visão de mundo.
description: Este Capítulo integra o livro "Le Brésil vu par les Brésiliens" - livro de fotografias fine art - outubro de 2016 - Editora Divine - Paris, França. ISBN 9782372750141
Covariant Hamiltonian approach for time-dependent potentials applied to a pill-box cavity
Creators: name: Laface, Emanuele
name: Folsom, Benjamin Tyler
Publisher: name: arXiv
Year: 2020
Subjects: subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Physical sciences

description: The common treatment of time-dependent potentials, such as those used for radio frequency cavities, is to average a potential's time component through the interval that the reference particle spends in the cavity. Such an approach, using the so-called transit-time factor, uses time as the independent variable in the Hamiltonian. In this paper, we instead propose a fully covariant Hamiltonian to treat the time component of the potential like any other space component. We show how to calculate the dynamics of the particles in a pill-box cavity using an explicit sympletic integrator. Finally, we compare the results with the simulator TraceWin.
Self-similarity of complex networks
Creators: name: Song, Chaoming
name: Havlin, Shlomo
name: Makse, Hernan A.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: Complex networks have been studied extensively due to their relevance to many real systems as diverse as the World-Wide-Web (WWW), the Internet, energy landscapes, biological and social networks \cite{ab-review,mendes,vespignani,newman,amaral}. A large number of real networks are called ``scale-free'' because they show a power-law distribution of the number of links per node \cite{ab-review,barabasi1999,faloutsos}. However, it is widely believed that complex networks are not {\it length-scale} invariant or self-similar. This conclusion originates from the ``small-world'' property of these networks, which implies that the number of nodes increases exponentially with the ``diameter'' of the network \cite{erdos,bollobas,milgram,watts}, rather than the power-law relation expected for a self-similar structure. Nevertheless, here we present a novel approach to the analysis of such networks, revealing that their structure is indeed self-similar. This result is achieved by the application of a renormalization procedure which coarse-grains the system into boxes containing nodes within a given "size". Concurrently, we identify a power-law relation between the number of boxes needed to cover the network and the size of the box defining a finite self-similar exponent. These fundamental properties, which are shown for the WWW, social, cellular and protein-protein interaction networks, help to understand the emergence of the scale-free property in complex networks. They suggest a common self-organization dynamics of diverse networks at different scales into a critical state and in turn bring together previously unrelated fields: the statistical physics of complex networks with renormalization group, fractals and critical phenomena.
description: 28 pages, 12 figures, more informations at http://www.jamlab.org
What is the price of abandoning dark matter? Cosmological constraints on alternative gravity theories
Creators: name: Pardo, Kris
name: Spergel, David N.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Any successful alternative gravity theory that obviates the need for dark matter must fit our cosmological observations. Measurements of microwave background polarization trace the large-scale baryon velocity field at recombination and show very strong, $O(1)$, baryon acoustic oscillations. Measurements of the large-scale structure of galaxies at low redshift show much weaker features in the spectrum. If the alternative gravity theory's dynamical equations for the growth rate of structure are linear, then the density field growth can be described by a Green's function: $δ(\vec x,t) = δ(\vec x,t')G(x,t,t')$. We show that the Green function, $G(x,t,t')$, must have dramatic features that erase the initial baryon oscillations. This implies an acceleration law that changes sign on the $\sim 150$ Mpc scale. On the other hand, if the alternative gravity theory has a large nonlinear term that couples modes on different scales, then the theory would predict large-scale non-Gaussian features in large-scale structure. These are not seen in the distribution of galaxies nor in the distribution of quasars. No proposed alternative gravity theory for dark matter seems to satisfy these constraints.
description: 6 pages, 3 figures. v2: matches version accepted for publication in PRL
Predicting Visual Importance Across Graphic Design Types
Creators: name: Fosco, Camilo
name: Casser, Vincent
name: Bedi, Amish Kumar
name: O'Donovan, Peter
name: Hertzmann, Aaron
name: Bylinskii, Zoya
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Graphics (cs.GR)
subject: Human-Computer Interaction (cs.HC)
subject: Image and Video Processing (eess.IV)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: This paper introduces a Unified Model of Saliency and Importance (UMSI), which learns to predict visual importance in input graphic designs, and saliency in natural images, along with a new dataset and applications. Previous methods for predicting saliency or visual importance are trained individually on specialized datasets, making them limited in application and leading to poor generalization on novel image classes, while requiring a user to know which model to apply to which input. UMSI is a deep learning-based model simultaneously trained on images from different design classes, including posters, infographics, mobile UIs, as well as natural images, and includes an automatic classification module to classify the input. This allows the model to work more effectively without requiring a user to label the input. We also introduce Imp1k, a new dataset of designs annotated with importance information. We demonstrate two new design interfaces that use importance prediction, including a tool for adjusting the relative importance of design elements, and a tool for reflowing designs to new aspect ratios while preserving visual importance. The model, code, and importance dataset are available at https://predimportance.mit.edu .
Theory of small aspect ratio waves in deep water
Creators: name: Kraenkel, A.
name: Leon, J.
name: Manna, M. A.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Pattern Formation and Solitons (nlin.PS)
subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: FOS: Physical sciences

description: In the limit of small values of the aspect ratio parameter (or wave steepness) which measures the amplitude of a surface wave in units of its wave-length, a model equation is derived from the Euler system in infinite depth (deep water) without potential flow assumption. The resulting equation is shown to sustain periodic waves which on the one side tend to the proper linear limit at small amplitudes, on the other side possess a threshold amplitude where wave crest peaking is achieved. An explicit expression of the crest angle at wave breaking is found in terms of the wave velocity. By numerical simulations, stable soliton-like solutions (experiencing elastic interactions) propagate in a given velocities range on the edge of which they tend to the peakon solution.
description: LaTex file, 16 pages, 4 figures
Promoting formal urban agricultural based organisations in the Greater Accra Metropolitan Area of Ghana: what factors influence choice?
Creators: name: Egyir, Irene Susana
name: Egyir, Irene Susana
Publisher: name: Unknown
Year: 2009
Subjects: subject: Agribusiness
subject: Agricultural and Food Policy
subject: Urban agriculture
subject: producer organisations
subject: logit model

description: This study uses data from a survey of 326 members of agricultural-based organisations in the Greater Accra Metropolitan Area of Ghana to model choice of formal organisation. People engaged in farming, and who perceive that they would reduce production and marketing risk, increase commodity sales and profits, reduce costs, improve rate of performance and can have a high level of trust for the members and leadership of the organisation were more likely to join formal organisations. These are the tangible benefits that members of formal organisations will require to commit. The study reiterates the necessity of appropriate role sharing and cooperation between the various government, non-governmental organisations and patrons for the success of formal agricultural-based organisations in urban centres.
description: agricultural producer organisations
Groupwise Multimodal Image Registration using Joint Total Variation
Creators: name: Brudfors, Mikael
name: Balbastre, Yaël
name: Ashburner, John
Publisher: name: arXiv
Year: 2020
Subjects: subject: Image and Video Processing (eess.IV)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: In medical imaging it is common practice to acquire a wide range of modalities (MRI, CT, PET, etc.), to highlight different structures or pathologies. As patient movement between scans or scanning session is unavoidable, registration is often an essential step before any subsequent image analysis. In this paper, we introduce a cost function based on joint total variation for such multimodal image registration. This cost function has the advantage of enabling principled, groupwise alignment of multiple images, whilst being insensitive to strong intensity non-uniformities. We evaluate our algorithm on rigidly aligning both simulated and real 3D brain scans. This validation shows robustness to strong intensity non-uniformities and low registration errors for CT/PET to MRI alignment. Our implementation is publicly available at https://github.com/brudfors/coregistration-njtv.
Two-Step Discontinuous Shear Thickening of Dilute Inertial Suspensions Having Soft-Core Potential
Creators: name: Sugimoto, Shuichi
name: Takada, Satoshi
Publisher: name: arXiv
Year: 2020
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Kinetic theory for dilute inertial suspension having soft-core potential is theoretically investigated. From the analysis of the scattering process, the expression of the scattering angle is analytically obtained. We derive the flow curve between the viscosity and the shear rate, which shows two-step discontinuous shear thickening when we change the softness of the particles. The molecular dynamics simulation shows that our theoretical results are consistent with the numerical ones.
description: 11 pages, 7 figures. Some typos are modified, and an addendum is added
Two remarks on non-zero constant Jacobian polynomial map of $C^2$
Creators: name: van Chau, Nguyen
Publisher: name: arXiv
Year: 2004
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14R15

description: We present some estimations on geometry of the exceptional value sets of non-zero constant Jacobian polynomial maps of $\C^2$ and it's components.
description: Latex
Participation by Men and Women in Off-Farm Activities: an Empirical Analysis in Rural Northern Ghana
Creators: name: McCarthy, Nancy
name: Sun, Yan
name: McCarthy, Nancy
name: Sun, Yan
Publisher: name: Unknown
Year: 2009
Subjects: subject: Labor and Human Capital
subject: off-farm labor supply
subject: participation
subject: community groups
subject: gender

description: The paper evaluates the household- and community-level factors influencing women’s and men’s decisions to participate in off-farm activities, either in the off-farm labor market or in local community groups, and the relationship with on-farm crop returns. Results reveals female participation in off-farm labor markets increases at higher levels of labor availability, and female on-farm work and group participation are complementary activities. Results also indicate that male labor is relatively more productive on-farm versus off-farm than female labor. Finally, the study shows that education increases the likelihood for both women and men to work off-farm, although the impact is greater for women.
Des Timotheos von Alexandrien, Schülers des h. Athanasios, Rede "in sanctam virginem Mariam et in salutationem Elisabeth"
Creators: name: Vardanean, Aristakês
Publisher: name: Oriens christianus : Hefte für die Kunde des christlichen Orients
Year: 2024

description: Oriens christianus : Hefte für die Kunde des christlichen Orients, Bd. 10 (1912): Oriens christianus, Band 10
Symbol Alphabets from Plabic Graphs
Creators: name: Mago, Jorge
name: Schreiber, Anders
name: Spradlin, Marcus
name: Volovich, Anastasia
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Symbol alphabets of n-particle amplitudes in N=4 super-Yang-Mills theory are known to contain certain cluster variables of Gr(4,n) as well as certain algebraic functions of cluster variables. In this paper we suggest an algorithm for computing these symbol alphabets from plabic graphs by solving matrix equations of the form C Z = 0 to associate functions on Gr(m,n) to parameterizations of certain cells of Gr(k,n) indexed by plabic graphs. For m=4 and n=8 we show that this association precisely reproduces the 18 algebraic symbol letters of the two-loop NMHV eight-point amplitude from four plabic graphs.
description: 19 pages; v2: minor corrections and improvements
Rice Production Response in Cambodia
Creators: name: Yu, Bingxin
name: Fan, Shenggen
name: Yu, Bingxin
name: Fan, Shenggen
Publisher: name: Unknown
Year: 2009
Subjects: subject: Agricultural and Food Policy
subject: Crop Production/Industries
subject: Food Security and Poverty
subject: Production Economics
subject: Production response
subject: government investment
subject: price
subject: rice
subject: Cambodia

description: This paper analyzes how Cambodian farmers and the government can respond to the rise of rice price. The study estimates rice production response in Cambodia using the Cambodia Socio-Economic Surveys (CSES) conducted in 2004 and 2007. The results indicate that agricultural productivity is far from its potential and can be increased substantially by using modern technology and inputs such as fertilizers and irrigation. Our findings also suggest that the Cambodian government needs to design its investment strategy to relax constraints in rural infrastructure such as transportation and electricity in order to increase its agricultural production and productivity and boost farmers’ income.
Sight word reading in children with developmental disabilities using picture communication symbols : a comparative study
Creators: name: Fossett, Brenda
Publisher: name: University of British Columbia
Year: 2009

description: Historically, children with developmental disabilities were often excluded from literacy instruction, particularly i f they were non-verbal. A growing body of research suggests this population can develop sight word reading skills. Numerous methods have been investigated; paired associate research recommends that pictures be removed from reading instruction while stimulus fading and picture-to-text matching research advocates the use of pictures in reading instruction. The present study used an adapted alternating treatments design (Sindelar, Rosenberg, & Wilson, 1985) to examine the use of Picture Communication Symbols (PCS) to develop a small sight word reading vocabulary in three non-reading individuals with developmental disabilities. The study compared two instructional conditions, paired associate learning and picture-to-text matching, and measured changes in participants' ability to match PCS to corresponding text. In the paired associate condition, PCS were always presented alongside text. In the picture-to-text matching condition, PCS were always presented separate from text. Results indicated that, for two participants, the picture-to-text matching condition was more effective than the paired associate condition for developing a small sight word vocabulary. The third participant was unable to complete the study due to difficulties in her personal life and did not demonstrate learning in either condition. Follow-up data for one participant showed that skills developed using the picture-to-text matching strategy were maintained up to 4 months after intervention. The results contribute to the existing research on sight word reading instruction and extend previous findings in a variety of ways. First, the study investigated the effectiveness of two different sight word instructional approaches, both of which used pictures. This was to clarify the role of pictures in sight word reading instruction. In addition, the study investigated two sight word instructional strategies that can be used to teach individuals who are unable to speak and are often excluded from literacy instruction. Finally, the study examined retention of sight word vocabulary over several months and suggested that the picture-to-text matching intervention can achieve long-lasting sight word reading skills. Further research is necessary to extend these findings, particularly in terms of the development of larger sight word vocabularies and the transition from sight word reading to more conventional reading skills.
Statistical hadronization with resonances
Creators: name: Torrieri, Giorgio
name: Letessier, Jean
name: Rafelski, Johann
name: Steinke, Steve
Publisher: name: arXiv
Year: 2004
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We introduce the equilibrium and non-equilibrium statistical hadronization picture of particle production in ultra-relativistic heavy ion collisions. We describe the related physical reaction scenarios, and show how these can lead to quark pair yield non-equilibrium. Using the SHARE1.2 program suite we quantitatively model particle yields and ratios for RHIC-130 run. We study how experimental particle ratios can differentiate between model scenarios, and discuss in depth the importance of hadronic resonances in understanding of hadron production processes.
description: Presented at the XLIV Crakow School of Theoretical Physics
A Typology of Food Security in Developing Countries under High Food Prices
Creators: name: Yu, Bingxin
name: You, Liangzhi
name: Fan, Shenggen
name: Yu, Bingxin
name: You, Liangzhi
name: Fan, Shenggen
Publisher: name: Unknown
Year: 2009
Subjects: subject: Agricultural and Food Policy
subject: Food Consumption/Nutrition/Food Safety
subject: Food Security and Poverty
subject: International Development
subject: Food security
subject: factor analysis
subject: agricultural potential
subject: typology
subject: trade

description: The recent surge in food prices around the world may reverse the gains of reducing hunger and poverty in the recent years. This paper employs factor and sequential typology analysis using data for 175 countries to identify groups of countries categorized according to four measures of food security: utilization, availability, accessibility and stability. Nine indicators are used for this study: calories intake, protein intake, fat intake, food production, the ratio of total exports to food imports, soil fertility, length of growing period, coefficient of variation of length of growing period and urbanization. The analysis first identifies 5 distinct food security groups characterized by food intake then further split these groups based on similarities and differences across the various measures of food production, trade security and agricultural potentials. The result suggests that the general category of “developing countries” is very heterogeneous and is not very useful if the focus is on issues of food security. Our food security classification is aligned with national income level and malnutrition status, but does not perfectly map to poverty headcount. The analysis provides tailored policy recommendations focusing on agricultural production for countries sharing the same typology.
An Experimental Economic Analysis of Carbon Trading Options for Australia
Creators: name: Tisdell, John G.
name: Grainger, Corinne
name: Tisdell, John G.
name: Grainger, Corinne
Publisher: name: Unknown
Year: 2009
Subjects: subject: Environmental Economics and Policy
subject: Resource /Energy Economics and Policy
subject: climate change
subject: emissions trading
subject: compliance

description: Australia is currently developing a carbon emissions trading program. The Garnaut report recommendations include options for the allocation of carbon credits, trading schemes, banking and borrowing, and self reporting mechanisms. This paper reports the results of a series of economic experiments in which we explored spot and future markets given high and low levels of carbon credit reductions. The results provide important insights to the current debate in Australia and highlight the importance of well crafted market design.
Neutron star inner crust: effects of rotation and magnetic fields
Creators: name: Sengo, Ivo
name: Pais, Helena
name: Franzon, Bruno
name: Providência, Constança
Publisher: name: arXiv
Year: 2020
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We study the role of the pasta phases on the properties of rotating and magnetized neutron stars. In order to investigate such systems, we make use of two different relativistic mean-field unified inner-crust--core equations of state, with a different density dependence of the symmetry energy, and an inner-crust computed within a Thomas-Fermi calculation. Special attention is given to the crust-core transition density, and the pasta phases effects on the global properties of stars. The effects of strong magnetic fields and fast rotation are computed by solving the Einstein-Maxwell equations self-consistently, taking into account anisotropies induced by the centrifugal and the Lorentz force. The location of the magnetic field neutral line and the maximum of the Lorentz force on the equatorial plane are calculated. The conditions under which they fall inside the inner crust region are discussed. We verified that models with a larger symmetry energy slope show more sensitivity to the variation of the magnetic field. One of the maxima of the Lorentz force, as well as the neutral line, and for a certain range of frequencies, fall inside the inner crust region. This may have consequences in the fracture of the crust, and may help explain phenomena associated with star quakes.
description: 10 pages, 8 figures, 3 tables; accepted for publication in PRD
The 6.7 keV KALPHA complex of He-like iron in transient plasmas
Creators: name: Oelgoetz, Justin
name: Pradhan, Anil K.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Time dependent numerical simulations of the K ALPHA complex of Fe XXV are carried out as a function of temperature/density/radiation field variations in high-temperature astrophysical and laboratory plasmas. In addition to several well known features, the transient and steady state spectra reveal the effects due to (a) time-dependent thermal and non-thermal radiation fields, (b) photo and collisional excitation and ionization, and (c) high densities, on the `quartet' of principal w,x,y,z lines, and dielectronic satellites. The highly detailed models show precisely how, assuming a temporal-temperature correlation, the X-ray intensity varies between 6.6 - 6.7 keV and undergoes a `spectral inversion' in the w and z line intensities, characterizing an ionization or a recombination dominated plasma. The dielectronic satellite intensities are the most temperature dependent features, but insensitive to density variations, and significantly contribute to the K ALPHA complex for T < 6.7 keV leading to asymmetric profiles. The 6.7 keV K ALPHA complex should be a potential diagnostic of X-ray flares in AGN, afterglows in gamma-ray bursts, and other non-equilibrium sources with the high-resolution measurements possible from the upcoming mission Astro-E2. It is also shown that high electron densities attenuate the line intensities in simulations relevant to laboratory plasmas, such as in inertial confinement fusion, laser, or magnetic Z-pinch devices.
description: 13 pages, 4 figures, 1 postscript coversheet. This is a preprint of an article accepted for publication in the Monthly Notices of the Royal Astronomical Society
Gravitational Theory, Galaxy Rotation Curves and Cosmology without Dark Matter
Creators: name: Moffat, J. W.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Einstein gravity coupled to a massive skew symmetric field F_{μνλ} leads to an acceleration law that modifies the Newtonian law of attraction between particles. We use a framework of non-perturbative renormalization group equations as well as observational input to characterize special renormalization group trajectories to allow for the running of the effective gravitational coupling G and the coupling of the skew field to matter. The latter lead to an increase of Newton's constant at large galactic and cosmological distances. For weak fields a fit to the flat rotation curves of galaxies is obtained in terms of the mass (mass-to-light ratio M/L) of galaxies. The fits assume that the galaxies are not dominated by exotic dark matter and that the effective gravitational constant G runs with distance scale. The equations of motion for test particles yield predictions for the solar system and the binary pulsar PSR 1913+16 that agree with the observations. The gravitational lensing of clusters of galaxies can be explained without exotic dark matter. An FLRW cosmological model with an effective G=G(t) running with time can lead to consistent fits to cosmological data without assuming the existence of exotic cold dark matter.
description: 33 pages, 20 figures, 1 table. Latex file. Additional text and references. Corrections. To be published in Journal of Cosmology and Astroparticle Physics (JCAP)
Gender and irrigation in India: the Women's Irrigation Group of Jambar, South Gujarat.
Creators: name: Van Koppen, Barbara
name: Nagar, Rashmi K.
name: Vasavada, Shilpa
name: Van Koppen, Barbara
name: Nagar, Rashmi K.
name: Vasavada, Shilpa
Publisher: name: Unknown
Year: 2001
Subjects: subject: Agribusiness
subject: Agricultural Finance
subject: Community/Rural/Urban Development
subject: Farm Management
subject: Food Consumption/Nutrition/Food Safety
subject: Production Economics
subject: Public Economics
subject: Risk and Uncertainty
subject: Irrigation management
subject: Women in development
subject: Gender
subject: Female labor
subject: Agricultural credit
subject: Decision making
subject: Irrigation programs
subject: Rain-fed farming
subject: Institution building
subject: Pumping
subject: India
subject: South Gujarat
subject: Bharuck
subject: Jambar

description: Documents a "best practice" - a successful gender-balanced irrigation intervention in which women were given control over an irrigation technology. The study evaluates the approach taken by the implementing NGO, the Aga Khan Rural Support Programme, in terms of its replicability in other areas where women share in farm activities and decision making.
Near-field spectra of quantum well excitons with non-Markovian phonon scattering
Creators: name: Mannarini, G.
name: Zimmermann, R.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The excitonic absorption spectrum for a disordered quantum well in presence of exciton-acoustic phonon interaction is treated beyond the Markov approximation. Realistic disorder exciton states are taken from a microscopic simulation, and the deformation potential interaction is implemented. The exciton Green's function is solved with a self energy in second order Born quality. The calculated spectra differ from a superposition of Lorentzian lineshapes by enhanced inter-peak absorption. This is a manifestation of pure dephasing which should be possible to measure in near-field experiments.
description: 8 pages, 7 figures
Modern Supply Chains and Product Innovation: How Can Smallholder Farmers Benefit?
Creators: name: Schipmann, Christin
name: Qaim, Matin
name: Schipmann, Christin
name: Qaim, Matin
Publisher: name: Unknown
Year: 2009
Subjects: subject: Community/Rural/Urban Development
subject: Marketing
subject: FOS: Economics and business
subject: Research Methods/ Statistical Methods
subject: Adoption
subject: Duration analysis
subject: Impact assessment
subject: Modern supply chains
subject: Product innovation
subject: Sweet pepper
subject: Thailand

description: There is an emerging body of literature analysing how smallholder farmers in developing countries can benefit from modern supply chains. However, most of the available studies concentrate on export markets and fail to capture spillover effects that modern supply chains may have on local markets. Here, we analyse the case of sweet pepper in Thailand, which was initially introduced as a product innovation in modern supply chains, but which is now widely traded also in more traditional markets. Using survey data from smallholder farmers and econometric techniques, we show that sweet pepper cultivation contributes significantly to higher household incomes. Strikingly, at this stage, participation in modern supply chains does not lead to higher incomes than supplying sweet pepper to traditional markets. However, the results also indicate that missing land titles, weak infrastructure conditions, and limited access to information constituted serious constraints during the early phases of sweet pepper adoption. Such constraints need to be overcome, so that smallholder farmers are better prepared for the prompt reactions needed under rapidly changing market conditions.
Chiral dynamics in QED and QCD in a magnetic background and nonlocal noncommutative field theories
Creators: name: Gorbar, E. V.
name: Homayouni, S.
name: Miransky, V. A.
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the connection of the chiral dynamics in QED and QCD in a strong magnetic field with noncommutative field theories (NCFT). It is shown that these dynamics determine complicated nonlocal NCFT. In particular, although the interaction vertices for electrically neutral composites in these gauge models can be represented in the space with noncommutative spatial coordinates, there is no field transformation that could put the vertices in the conventional form considered in the literature. It is unlike the Nambu-Jona-Lasinio (NJL) model in a magnetic field where such a field transformation can be found, with a cost of introducing an exponentially damping form factor in field propagators. The crucial distinction between these two types of models is in the characters of their interactions, being short-range in the NJL-like models and long-range in gauge theories. The relevance of the NCFT connected with the gauge models for the description of the quantum Hall effect in condensed matter systems with long-range interactions is briefly discussed.
description: 19 pages, REVTeX4, v2: clarifications added, v3: to match PRD version
Coulomb collisions in strongly anisotropic plasmas II. Cyclotron cooling in laboratory pair plasmas
Creators: name: Kennedy, Daniel
name: Helander, Per
Publisher: name: arXiv
Year: 2020
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: The behaviour of a strongly-magnetized collisional electron-positron plasma which is optically thin to cyclotron radiation is considered, and the distribution functions accessible to it on the various timescales in the system are calculated. Particular attention is paid to the limit in which the collision time exceeds the radiation emission time, making the electron distribution function strongly anisotropic. Indeed, these are the exact conditions likely to be attained in the first laboratory electron-positron plasma experiments currently being developed, which will typically have very low densities and be confined in very strong magnetic fields. The constraint of strong-magnetization adds an additional complication in that long-range Coulomb collisions, which are usually negligible, must now be considered. A rigorous collision operator for these long-range collisions has never been written down. Nevertheless, we show that the collisional scattering can be accounted for without knowing the explicit form of this collision operator. The rate of radiation emission is calculated and it is found that the loss of energy from the plasma is proportional to the parallel collision frequency multiplied by a factor that only depends logarithmically on plasma parameters. That is, this is a self-accelerating process, meaning that the bulk of the energy will be lost in a few collision times. We show that in a simple case, that of straight field-line geometry, there are no unstable drift waves in such plasmas, despite being far from Maxwellian.
Google Apps Script: instructivo
Creators: name: Vazano, Irene Noé
name: Black, Melissa
name: Nanton, María Cristina
name: Buede, Julián
name: López, Sabrina
name: Poggio, Iván Gabriel
Publisher: name: Zenodo
Year: 2024
Subjects: Ciencia Abierta
Comunidad
Teaching
Latin America
Enseñanza
Clases virtuales
Pedagogía
Programación
Docencia
Cursos

description: Instructivo basado en la experiencia de MetaDocencia para las organizaciones que necesiten utilizar la plataforma Google Apps Script para cumplir sus objetivos.
An Indexing Scheme and Descriptor for 3D Object Retrieval Based on Local Shape Querying
Creators: name: van Blokland, Bart Iver
name: Theoharis, Theoharis
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: A binary descriptor indexing scheme based on Hamming distance called the Hamming tree for local shape queries is presented. A new binary clutter resistant descriptor named Quick Intersection Count Change Image (QUICCI) is also introduced. This local shape descriptor is extremely small and fast to compare. Additionally, a novel distance function called Weighted Hamming applicable to QUICCI images is proposed for retrieval applications. The effectiveness of the indexing scheme and QUICCI is demonstrated on 828 million QUICCI images derived from the SHREC2017 dataset, while the clutter resistance of QUICCI is shown using the clutterbox experiment.
description: 13 pages, 13 figures, to be published in a Special Issue in Computers & Graphics
Flexible all-PM NALM Yb:fiber laser design for frequency comb applications: operation regimes and their noise properties
Creators: name: Mayer, Aline S.
name: Grosinger, Wilfrid
name: Fellinger, Jakob
name: Winkler, Georg
name: Perner, Lukas W.
name: Droste, Stefan
name: Salman, Sarper H.
name: Li, Chen
name: Heyl, Christoph M.
name: Hartl, Ingmar
name: Heckl, Oliver H.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We present a flexible all-polarization-maintaining (PM) mode-locked ytterbium (Yb):fiber laser based on a nonlinear amplifying loop mirror (NALM). In addition to providing detailed design considerations, we discuss the different operation regimes accessible by this versatile laser architecture and experimentally analyze five representative mode-locking states. These five states were obtained in a 78-MHz configuration at different intracavity group delay dispersion (GDD) values ranging from anomalous (-0.035 ps$^2$) to normal (+0.015 ps$^2$). We put a particular focus on the characterization of the intensity noise as well as the free-running linewidth of the carrier-envelope-offset (CEO) frequency as a function of the different operation regimes. We observe that operation points far from the spontaneous emission peak of Yb (~1030 nm) and close to zero intracavity dispersion can be found, where the influence of pump noise is strongly suppressed. For such an operation point, we show that a CEO linewidth of less than 10-kHz at 1 s integration can be obtained without any active stabilization.
Decomposition of Agricultural Labor Productivity Growth and its Regional Disparity in China
Creators: name: Xin, Xiangfei
name: Qin, Fu
name: Xin, Xiangfei
name: Qin, Fu
Publisher: name: Unknown
Year: 2009
Subjects: subject: Productivity Analysis
subject: Agricultural labor productivity growth
subject: Decomposition
subject: Regional disparity

description: This paper studies the regional disparity of China's agricultural productivity growth by decomposing it into technical changes, efficiency changes and input accumulation per worker. The convergence test is also used to analyze the determinants of regional disparity. The paper finds that during 1987 and 2005, although the growth of China’s agricultural labor productivity mainly depended on the accumulation of inputs, technical changes contributed more to regional disparities in agricultural productivity growth. Improving efficiency to promote TFP growth is important for agricultural labor productivity growth for the three regions—Eastern, Central and Western of China. The increase in inputs for Western China, and the improvement in technical change for Central and Western China are significant aspects to promote the growth of agricultural productivity and narrow the gap with the Eastern China.
Paradigmi, Spie e Fallacie
Creators: name: Sparavigna, Amelia Carolina
Publisher: name: Zenodo
Year: 2021
Subjects: paradigma
paradigma indiziario
pensiero induttivo
falsificazione
paradigma di Wason
pregiudizio di conferma
fallacia
non sequitur
fallacia emotiva
rasoio di Occam
scopa di Occam
bulverismo
benaltrismo
ad misericordiam
ad baculum
ad personam
ad ridiculum
accusa indiretta
argomento fantoccio
accumulo di postille
uso dei testimoni
verità della maggioranza
volontà superiore
piano inclinato
ad populum
ipse dixit
polemica
i pozzi
luoghi comuni
onere della prova
topoi retorici
Gorgia
proverbi
versi celebri
favole
parabole
Cicerone
Pro Fonteio

description: Questa è una raccolta di appunti per sviluppare una discussione sui vari aspetti dei paradigmi nelle scienze. Si amplia con spie e fallacie. Del paradigma indiziario ne parla Carlo Ginzburg. Si vedranno poi le fallacie, e come si arrivi ai topoi retorici, con uso di versi celebri, proverbi, favole e parabole. Incontreremo anche Ignazio di Loyola, in relazione all'argumentum ad baculum e Cicerone ed i testimoni barbari.
description: Si veda anche la Raccolta di discussioni sul pregiudizio di conferma. Zenodo. http://doi.org/10.5281/zenodo.4273991
Cosmological N-Body simulation: Techniques, Scope and Status
Creators: name: Bagla, J. S.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Cosmological N-Body simulations have become an essential tool for studying formation of large scale structure. These simulations are computationally challenging even though the available computing power gets better every year. A number of efficient algorithms have been developed to run large simulations with better dynamic range and resolution. We discuss key algorithms in this review, focusing on techniques used and their efficacy. N-Body simulations solve a model that is an approximation of the physical model to be simulated, we discuss limitations arising from this approximation and techniques employed for solving equations. Apart from simulating models of structure formation, N-Body simulations have also been used to study aspects of gravitational clustering. Simulating formation of galaxies requires us to take many physical process into account; we review numerical implementations of key processes.
description: Invited Review; To appear in Current Science (special issue on Cosmology, Guest editor T.Padmanabhan)
Stress Probe
Creators: name: Okello, Moses
Publisher: name: figshare
Year: 2024
Subjects: classificationCode: 400510
subject: Structural engineering

description: This structural stress and deformation analysis shows the effects of an unevenly distributed load on a box shape with and without reinforced support when either the middle portion of the box is supported by a fixed support or both ends are.Software used for simulation; ANSYS Student Version 2023 R1.Statics Structural Analysis
Robotics Software Engineering: A Perspective from the Service Robotics Domain
Creators: name: García, Sergio
name: Strüber, Daniel
name: Brugali, Davide
name: Berger, Thorsten
name: Pelliccione, Patrizio
Publisher: name: arXiv
Year: 2020
Subjects: subject: Software Engineering (cs.SE)
subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: Robots that support humans by performing useful tasks (a.k.a., service robots) are booming worldwide. In contrast to industrial robots, the development of service robots comes with severe software engineering challenges, since they require high levels of robustness and autonomy to operate in highly heterogeneous environments. As a domain with critical safety implications, service robotics faces a need for sound software development practices. In this paper, we present the first large-scale empirical study to assess the state of the art and practice of robotics software engineering. We conducted 18 semi-structured interviews with industrial practitioners working in 15 companies from 9 different countries and a survey with 156 respondents (from 26 countries) from the robotics domain. Our results provide a comprehensive picture of (i) the practices applied by robotics industrial and academic practitioners, including processes, paradigms, languages, tools, frameworks, and reuse practices, (ii) the distinguishing characteristics of robotics software engineering, and (iii) recurrent challenges usually faced, together with adopted solutions. The paper concludes by discussing observations, derived hypotheses, and proposed actions for researchers and practitioners.
description: 11 pages + 1 page for references, 3 figures, 3 tables, in proceedings of ESEC/FSE 2020