cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Efficient ion acceleration driven by a Laguerre Gaussian laser in near-critical-density plasma
Creators: name: Gao, Jia-Xiang
name: Liu, Meng
name: Wang, Wei-Min
Publisher: name: arXiv
Year: 2023
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: Accelerator Physics (physics.acc-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Laser-driven ion accelerators have the advantages of compact size, high density, and short bunch duration over conventional accelerators. Nevertheless, it is still challenging to generate ion beams with quasi-monoenergetic peak and low divergence in the experiments with the current ultra-high intensity laser and thin target technologies. Here we propose a scheme that a Laguerre Gaussian laser irradiates a near-critical-density (NCD) plasma to generate a quasi-monoenergetic and low-divergence proton beam. The Laguerre Gaussian laser pulse in NCD plasma excites a moving longitudinal electrostatic field with a large amplitude, and it maintains the inward bowl-shape for dozens of laser durations. This special distribution of the longitudinal electrostatic field can accelerate and converge the protons simultaneously. Our particle-in-cell (PIC) simulation shows that the efficient proton acceleration can be realized with the Laguerre Gaussian laser intensity ranging from 3.9-10^21 Wcm^-2 -1.6-10^22 Wcm^-2 available in the near future, e.g., a quasi-monoenergetic proton beam with peak energy ~115 MeV and divergence angles less than 50 can be generated by a 5.3-10^21 Wcm^-2 pulse. This work could provide a reference for the high-quality ion beam generation with PW-class laser systems available recently.
description: 11 pages, 5 figures
Three dimensional Yukawa models and CFTs at strong and weak couplings
Creators: name: Pinto, Marcus Benghi
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The massless three dimensional Gross-Neveu-Yukawa (GNY) and Nambu--Jona-Lasinio--Yukawa (NJLY) models at finite temperatures are analyzed within the mean field framework considering all coupling values. When the number of Dirac fermions is taken to be $N_f=1/4$ (GNY) and $N_f=1/2$ (NJLY) these models relate to the supersymmetric Wess-Zumino (WZ) theory with cubic superpotential and one superfield. In this case the results show that the strong-weak entropy density ratio decreases from the Stefan-Boltzmann value, in the weak limit, to $s/s_{free}=31/35$ at strong couplings. This value agrees with the one recently obtained by applying the large-$N$ approximation to the supersymmetric $O(N)$ WZ model with quartic superpotential and $N$ superfields. When $N_f=0$ one obtains $s/s_{free}=4/5$ recovering, as expected, the ratio predicted in the context of the $O(N)$ scalar model. However, contrary to the $O(N)$ WZ model the simple Yukawa models analyzed here do not behave as CFTs for all couplings since the conformal measure exactly vanishes only at the extreme weak and strong limits although the speed of sound indicates that the deviation, at intermediate couplings, appears to be rather small. By comparing the thermal masses behavior in each case one can trace this difference as being a consequence that in the GNY/NJLY case the fermionic mass vanishes for all couplings while within the $O(N)$ WZ it only vanishes at the weak and strong limits. On the other hand, the Yukawa bosonic dimensionless masses display a more universal behavior decreasing from $2 \ln [(1+\sqrt{5})/2]$, at infinite coupling, to zero (at vanishing coupling).
To Till or Not to Till? Social Profitability of No-Till Technology
Creators: name: Lankoski, Jussi E.
name: Ollikainen, Markku
name: Uusitalo, Pekka
name: Lankoski, Jussi E.
name: Ollikainen, Markku
name: Uusitalo, Pekka
Publisher: name: Unknown
Year: 2005
Subjects: subject: Crop Production/Industries
subject: nutrient runoffs
subject: herbicide runoffs
subject: buffer strips
subject: agri-environmental policy

description: We study from economic and environmental angles under what conditions no-till technology is socially optimal. We demonstrate theoretically that if yield under no-till is equal to or greater than under conventional technology, its adoption is socially optimal provided that herbicide runoff damages under both technologies are close enough. Finnish data shows, however, that only in one case out of three no-till provides higher social returns. In terms of nutrient runoffs no-till performs better than conventional technology. No-till reduces surface runoffs of nitrogen by 58%, and surface runoffs of particulate phosphorus by 70% relative to conventional technology, but causes more than three times higher dissolved phosphorus surface runoffs. The amount of total phosphorus surface runoff is, however, lower under no-till. No-till produces higher total herbicide runoff because of higher use of herbicides to control perennial weeds.
GROUNDNUT TRADE LIBERALIZATION: A SOUTH-SOUTH DEBATE?
Creators: name: Beghin, John C.
name: Diop, Ndiame
name: Matthey, Holger
name: Sewadeh, Mirvat
name: Beghin, John C.
name: Diop, Ndiame
name: Matthey, Holger
name: Sewadeh, Mirvat
Publisher: name: Unknown
Year: 2003
Subjects: subject: Crop Production/Industries
subject: International Relations/Trade
subject: distortion
subject: Doha
subject: groundnuts
subject: negotiations
subject: oil
subject: peanut
subject: protection
subject: trade liberalization

description: We use a new partial-equilibrium, multi-market international model to analyze trade and agricultural policies affecting markets for peanut/groundnut products. The model covers four goods in thirteen countries/regions, including a large set of developing countries. Welfare is evaluated by looking at consumers' equivalent variation, quasi-profits in farming, quasi-profits in crushing, and taxpayers' revenues and outlays implied by distortions. We calibrate the model on recent historical data and current policy information. We analyze several groundnut trade liberalization scenarios in deviation from the recent historical baseline. Trade liberalization in groundnut markets has a strong South-South dimension, opposing India and, to a lesser extent, China to smaller developing countries mainly located in Africa. In the former, current policies, exacerbated by their market size, depress the world prices of groundnut products. Under free trade, African exporters present in these world markets would gain because they are net sellers of groundnut products. In India, consumers would be better off, with lower consumer prices resulting from the removal of prohibitive tariffs and large imports of groundnut products. The cost of the adjustment would fall on Indian farmers and crushers. In China, crush margins would improve because of the large terms-of-trade effects in the oil market relative to the seed market. China's groundnut product exports would expand dramatically. Net buyers of groundnut products in OECD (Organisation of Economic Co-operation and Development) countries would be worse off. We draw implications for Doha negotiations.
Behavioral Incentives, Equilibrium Endemic Disease, and Health Management Policy for Farmed Animals
Creators: name: Hennessy, David A.
name: Hennessy, David A.
Publisher: name: Unknown
Year: 2005
Subjects: subject: Livestock Production/Industries
subject: biosecurity
subject: continuous time
subject: multiple equilibria
subject: Nash behavior
subject: reinfection

description: We develop a dynamic capital valuation model in which each farm can take an action with farm-varying cost to increase the probability of not contracting a disease. In the presence of infection externalities, circumstances are identified under which multiple equilibria exist and where the one involving the most extensive set of action takers is socially optimal. It is suggested that costly capital markets are one factor in determining the extent of endemic disease in a region. The introduction of frictions, such as dealing with a cumbersome veterinary public health bureaucracy, can enhance social welfare by encouraging precautionary biosecurity actions. Some technical innovations can reduce social welfare. The model is also extended to study a voluntary herd depopulation scheme. Moral hazard in the biosecurity action will dampen the scheme's welfare effect.
Signature of Carrier-Induced Ferromagnetism in Ti_{1-x}Co_{x}O_{2-delta}: Exchange Interaction Between High-Spin Co 2+ and the Ti 3d Conduction Band
Creators: name: Quilty, J. W.
name: Shibata, A.
name: Son, J. -Y.
name: Takubo, K.
name: Mizokawa, T.
name: Toyosaki, H.
name: Fukumura, T.
name: Kawasaki, M.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: X-ray photoemission spectroscopy measurements were performed on thin-film samples of rutile Ti_{1-x}Co_{x}O_{2-delta} to reveal the electronic structure. The Co 2p core level spectra indicate that the Co ions take the high-spin Co 2+ configuration, consistent with substitution on the Ti site. The high spin state and the shift due to the exchange splitting of the conduction band suggest strong hybridization between carriers in the Ti 3d t2g band and the t2g states of the high-spin Co 2+. These observations support the argument that room temperature ferromagnetism in Ti_{1-x}Co_{x}O_{2-delta} is intrinsic.
description: 4 pages, 5 figures. Accepted for publication in Physical Review Letters
On-line predictive linear regression
Creators: name: Vovk, Vladimir
name: Nouretdinov, Ilia
name: Gammerman, Alex
Publisher: name: arXiv
Year: 2005
Subjects: subject: Statistics Theory (math.ST)
subject: FOS: Mathematics
subject: 62G08, 62J07

description: We consider the on-line predictive version of the standard problem of linear regression; the goal is to predict each consecutive response given the corresponding explanatory variables and all the previous observations. We are mainly interested in prediction intervals rather than point predictions. The standard treatment of prediction intervals in linear regression analysis has two drawbacks: (1) the classical prediction intervals guarantee that the probability of error is equal to the nominal significance level epsilon, but this property per se does not imply that the long-run frequency of error is close to epsilon; (2) it is not suitable for prediction of complex systems as it assumes that the number of observations exceeds the number of parameters. We state a general result showing that in the on-line protocol the frequency of error for the classical prediction intervals does equal the nominal significance level, up to statistical fluctuations. We also describe alternative regression models in which informative prediction intervals can be found before the number of observations exceeds the number of parameters. One of these models, which only assumes that the observations are independent and identically distributed, is popular in machine learning but greatly underused in the statistical theory of regression.
description: 34 pages; 6 figures; 1 table. arXiv admin note: substantial text overlap with arXiv:0906.3123
Modular Calabi-Yau threefolds of level eight
Creators: name: Cynk, S.
name: Meyer, C.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Algebraic Geometry (math.AG)
subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 14G10; 14J32

description: In the studies on the modularity conjecture for rigid Calabi-Yau threefolds several examples with the unique level 8 cusp form were constructed. According to the Tate Conjecture correspondences inducing isomorphisms on the middle cohomologies should exist between these varieties. In the paper we construct several examples of such correspondences. In the constructions elliptic fibrations play a crucial role. In fact we show that all but three examples are in some sense built upon two modular curves from the Beauville list.
description: 18 pages, 1 figure
Two dimensionality in quasi one-dimensional cobalt oxides
Creators: name: Sugiyama, J.
name: Nozaki, H.
name: Brewer, J. H.
name: Ansaldo, E. J.
name: Takami, T.
name: Ikuta, H.
name: Mizutani, U.
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: By means of muon spin rotation and relaxation ($μ^+$SR) techniques, we have investigated the magnetism of quasi one-dimensional (1D) cobalt oxides $AE_{n+2}$Co$_{n+1}$O$_{3n+3}$ ($AE$=Ca, Sr and Ba, $n$=1, 2, 3, 5 and $\infty$), in which the 1D CoO$_3$ chain is surrounded by six equally spaced chains forming a triangular lattice in the $ab$-plane, using polycrystalline samples, from room temperature down to 1.8 K. For the compounds with $n$=1 - 5, transverse field $μ^+$SR experiments showed the existence of a magnetic transition below $\sim$100 K. The onset temperature of the transition ($T_{\rm c}^{\rm on}$) was found to decrease with $n$; from 100 K for $n$=1 to 60 K for $n$=5. A damped muon spin oscillation was observed only in the sample with $n$=1 (Ca$_3$Co$_2$O$_6$), whereas only a fast relaxation obtained even at 1.8 K in the other three samples. In combination with the results of susceptibility measurements, this indicates that a two-dimensional short-range antiferromagnetic (AF) order appears below $T_{\rm c}^{\rm on}$ for all compounds with $n$=1 - 5; but quasi-static long-range AF order formed only in Ca$_3$Co$_2$O$_6$, below 25 K. For BaCoO$_3$ ($n$=$\infty$), as $T$ decreased from 300 K, 1D ferromagnetic (F) order appeared below 53 K, and a sharp 2D AF transition occurred at 15 K.
description: 12 pages, 14 figures, and 2 tables
Model for a Universe described by a non-minimally coupled scalar field and interacting dark matter
Creators: name: Binder, J. B.
name: Kremer, G. M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this work it is investigated the evolution of a Universe where a scalar field, non-minimally coupled to space-time curvature, plays the role of quintessence and drives the Universe to a present accelerated expansion. A non-relativistic dark matter constituent that interacts directly with dark energy is also considered, where the dark matter particle mass is assumed to be proportional to the value of the scalar field. Two models for dark matter pressure are considered: the usual one, pressureless, and another that comes from a thermodynamic theory and relates the pressure with the coupling between the scalar field and the curvature scalar. Although the model has a strong dependence on the initial conditions, it is shown that the mixture consisted of dark components plus baryonic matter and radiation can reproduce the expected red-shift behavior of the deceleration parameter, density parameters and luminosity distance.
description: 11 pages and 6 figures. To appear in GRG
Far-field model of two-color laser driven terahertz radiation including field element interference and plasma response
Creators: name: Li, Nan
name: Wang, Wei-Min
Publisher: name: arXiv
Year: 2023
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: The two-color laser field scheme for broad-band terahertz (THz) radiation from air has been intensively and broadly investigated due to the simplicity in technology and relative high yield efficiency. Experiments showed that the detected THz angular distribution is usually conical with a dip in the laser propagation axis which is unfavorable for its application, and the formation of an oscillating tail in the THz waveform has not yet been well understood. Here, we develop an electric field element interference model in which each local current source has a phase velocity determined by the laser pulse and a Gaussian temporal profile, rather than an ideal point source, as well as the current oscillation caused by the plasma dynamics is considered. By introducing the temporal interference, effects of the phase velocity and the Gaussian profile of the current can correct the THz angular distribution. Therefore, by adjusting the laser pulse duration and the group velocity, the THz angular distribution can be controlled and the dip could be even eliminated. Besides, the plasma dynamics can result in the formation of an oscillating tail in the THz waveform and sunken spikes in the corresponding spectrum. This is similar to the experimental results which are usually explained by the water vapor absorption. In turn, the spikes in the spectrum could provide a way to measure the plasma filament density.
description: 25 pages, 6 figures
THE IMPACT OF THE BERLIN ACCORD AND EUROPEAN ENLARGEMENT ON DAIRY MARKETS
Creators: name: Fuller, Frank H.
name: Beghin, John C.
name: Mohanty, Samarendu
name: Fabiosa, Jacinto F.
name: Fang, Cheng
name: Kaus, Phillip J.
name: Fuller, Frank H.
name: Beghin, John C.
name: Mohanty, Samarendu
name: Fabiosa, Jacinto F.
name: Fang, Cheng
name: Kaus, Phillip J.
Publisher: name: Unknown
Year: 1999
Subjects: subject: International Relations/Trade
subject: Livestock Production/Industries
subject: Berlin Accord
subject: Common Agricultural Policy
subject: dairy markets
subject: European Union enlargement

description: Using a world agricultural model, we analyze the impact on dairy markets of the Berlin Accord on the European Union (EU) Common Agricultural Policy (CAP) Reforms. We also investigate the consequences of enlargement of the EU to include the Czech Republic, Hungary, and Poland for the same markets. We produce a market outlook up to 2010 for these two scenarios. The Berlin Accord induces lower EU milk and dairy prices. A change in relative prices between cheese and butter-skim milk powder (SMP) occurs after 2005 and induces an expansion of cheese production, consumption, and exports at the expense of the butter-SMP sector. Accession of the three Central and Eastern European countries (CEECs) leads to a permanent but moderate decrease in EU prices of milk and dairy products. For the three acceding CEECs, domestic prices increase dramatically. Their final consumption of milk decreases and dairy product consumption drops considerably. The derived demand of milk in dairy production increases, however, because of the higher prices for dairy products, benefiting dairy producers in these CEECs. Dairy exports of the three acceding countries to the EU-15 increase by one to three orders of magnitude, despite building large inventories. The impact of accession on world markets is small.
Entanglement monotones for multi-qubit states based on geometric invariant theory
Creators: name: Heydari, Hoshang
Publisher: name: arXiv
Year: 2005
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We construct entanglement monotones for multi-qubit states based on Plücker coordinate equations of Grassmann variety, which are central notion in geometric invariant theory. As an illustrative example, we in details investigate entanglement monotones of a three-qubit state.
description: 6 pages
A continuum model for the growth of dendritic actin networks
Creators: name: Abeyaratne, Rohan
name: Purohit, Prashant K.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Biological Physics (physics.bio-ph)
subject: FOS: Physical sciences

description: Polymerization of dendritic actin networks underlies important mechanical processes in cell biology such as the protrusion of lamellipodia, propulsion of growth cones in dendrites of neurons, intracellular transport of organelles and pathogens, among others. The forces required for these mechanical functions have been deduced from mechano-chemical models of actin polymerization; most models are focused on single growing filaments, and only a few address polymerization of filament networks through simulations. Here we propose a continuum model of surface growth and filament nucleation to describe polymerization of dendritic actin networks. The model describes growth and elasticity in terms of macroscopic stresses, strains and filament density rather than focusing on individual filaments. The microscopic processes underlying polymerization are subsumed into kinetic laws characterizing the change of filament density and the propagation of growing surfaces. This continuum model can predict the evolution of actin networks in disparate experiments. A key conclusion of the analysis is that existing laws relating force to polymerization speed of single filaments cannot predict the response of growing networks. Therefore a new kinetic law, consistent with the dissipation inequality, is proposed to capture the evolution of dendritic actin networks under different loading conditions. This model may be extended to other settings involving a more complex interplay between mechanical stresses and polymerization kinetics, such as the growth of networks of microtubules, collagen filaments, intermediate filaments and carbon nanotubes.
Multi-Fidelity Machine Learning for Excited State Energies of Molecules
Creators: name: Vinod, Vivin
name: Maity, Sayan
name: Zaspel, Peter
name: Kleinekathöfer, Ulrich
Publisher: name: arXiv
Year: 2023
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: Machine Learning (cs.LG)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: The accurate but fast calculation of molecular excited states is still a very challenging topic. For many applications, detailed knowledge of the energy funnel in larger molecular aggregates is of key importance requiring highly accurate excited state energies. To this end, machine learning techniques can be an extremely useful tool though the cost of generating highly accurate training datasets still remains a severe challenge. To overcome this hurdle, this work proposes the use of multi-fidelity machine learning where very little training data from high accuracies is combined with cheaper and less accurate data to achieve the accuracy of the costlier level. In the present study, the approach is employed to predict the first excited state energies for three molecules of increasing size, namely, benzene, naphthalene, and anthracene. The energies are trained and tested for conformations stemming from classical molecular dynamics simulations and from real-time density functional tight-binding calculations. It can be shown that the multi-fidelity machine learning model can achieve the same accuracy as a machine learning model built only on high cost training data while having a much lower computational effort to generate the data. The numerical gain observed in these benchmark test calculations was over a factor of 30 but certainly can be much higher for high accuracy data.
Fluctuations of the luminosity distance
Creators: name: Bonvin, Camille
name: Durrer, Ruth
name: Gasparini, M. Alice
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We derive an expression for the luminosity distance in a perturbed Friedmann universe. We define the correlation function and the power spectrum of the luminosity distance fluctuations and express them in terms of the initial spectrum of the Bardeen potential. We present semi-analytical results for the case of a pure CDM universe. We argue that the luminosity distance power spectrum represents a new observational tool which can be used to determine cosmological parameters. In addition, our results shed some light into the debate whether second order small scale fluctuations can mimic an accelerating universe.
description: 23 pages, 15 figures, errors in published version corrected (eqs. (53), (55), (58) and (59))
Core Structure of Intracluster Gas: Isothermal Hydrostatic Equilibrium
Creators: name: Akahori, Takuya
name: Masai, Kuniaki
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We investigate core structures of X-ray emitting intracluster gas based on the so-called beta-model, which is an isothermal hydrostatic model often used in observational studies. We reconsider the beta-model and find that the virial temperature T_vir of a cluster may be represented better by beta T_X than T_X, where beta is the parameter obtained from the X-ray surface brightness and T_X is the emission-weighted mean temperature of the gas. We investigate 121 clusters observed by ROSAT and ASCA and find that the luminosity-temperature relation L_X - beta T_X is less steep than L_X - T_X. We classify the clusters into two core-size groups in order to investigate their properties in detail. While in the larger core group the core radius is marginally proportional to the virial radius, no significant relation is found for the smaller core group. This may suggest that the smaller cores reflect the presence of cD galaxies, effect of radiative cooling or asymmetry in the surface brightness. We examine such possibilities, and find that the clusters of smaller cores have shorter cooling time than the Hubble time, while no significant correlation is found with cD or asymmetry. We carry out hydrodynamical calculations to simulate the beta-model, intending to see the behavior of the isothermal gas under the gravitational potential including the dark matter and galaxies with or without a central cD galaxy. Calculations show r_c \propto r_vir and T_vir \simeq beta T consistently with our consideration to the beta-model. Also is found from calculations that the presence of a large cD galaxy may form a gas core \sim 40 kpc, which seems too small to account for the range of the core sizes, 40--80 kpc, of the smaller core group.
description: 9 pages, 10 figures; To be published in PASJ vol 57, No. 3 (June 2005)
Get a GRIP: Should Area Revenue Coverage Be Offered through the Farm Bill or as a Crop Insurance Program?
Creators: name: Paulson, Nicholas D.
name: Babcock, Bruce A.
name: Paulson, Nicholas D.
name: Babcock, Bruce A.
Publisher: name: Unknown
Year: 2007
Subjects: subject: Agricultural and Food Policy
subject: Risk and Uncertainty
subject: area revenue insurance
subject: commodity programs
subject: crop insurance
subject: Group Risk Income Protection

description: The successful expansion of the U.S. crop insurance program has not eliminated ad hoc disaster assistance. An alternative currently being explored by members of Congress and others in preparation of the 2007 farm bill is to simply remove the "ad hoc" part of disaster assistance programs by creating a standing program that would automatically funnel aid to hard-hit regions and crops. One form such a program could take can be found in the area yield and area revenue insurance programs currently offered by the U.S. crop insurance program. The Group Risk Plan (GRP) and Group Risk Income Protection (GRIP) programs automatically trigger payments when county yields or revenues, respectively, fall below a producer-elected coverage level. The per-acre taxpayer costs of offering GRIP in Indiana, Illinois, and Iowa for corn and soybeans through the crop insurance program are estimated. These results are used to determine the amount of area revenue coverage that could be offered to farmers as part of a standing farm bill disaster program. Approximately 55% of taxpayer support for GRIP flows to the crop insurance industry. A significant portion of this support comes in the form of net underwriting gains. The expected rate of return on money put at risk by private crop insurance companies under the current Standard Reinsurance Agreement is approximately 100%. Taking this industry support and adding in the taxpayer support for GRIP that flows to producers would fund a county target revenue program at the 93% coverage level.
Causal Network Models of SARS-CoV-2 Expression and Aging to Identify Candidates for Drug Repurposing
Creators: name: Belyaeva, Anastasiya
name: Cammarata, Louis
name: Radhakrishnan, Adityanarayanan
name: Squires, Chandler
name: Yang, Karren Dai
name: Shivashankar, G. V.
name: Uhler, Caroline
Publisher: name: arXiv
Year: 2020
Subjects: subject: Molecular Networks (q-bio.MN)
subject: FOS: Biological sciences

description: Given the severity of the SARS-CoV-2 pandemic, a major challenge is to rapidly repurpose existing approved drugs for clinical interventions. While a number of data-driven and experimental approaches have been suggested in the context of drug repurposing, a platform that systematically integrates available transcriptomic, proteomic and structural data is missing. More importantly, given that SARS-CoV-2 pathogenicity is highly age-dependent, it is critical to integrate aging signatures into drug discovery platforms. We here take advantage of large-scale transcriptional drug screens combined with RNA-seq data of the lung epithelium with SARS-CoV-2 infection as well as the aging lung. To identify robust druggable protein targets, we propose a principled causal framework that makes use of multiple data modalities. Our analysis highlights the importance of serine/threonine and tyrosine kinases as potential targets that intersect the SARS-CoV-2 and aging pathways. By integrating transcriptomic, proteomic and structural data that is available for many diseases, our drug discovery platform is broadly applicable. Rigorous in vitro experiments as well as clinical trials are needed to validate the identified candidate drugs.
Dyadic Green Function for an Electromagnetic Medium Inspired by General Relativity
Creators: name: Lakhtakia, Akhlesh
name: Mackay, Tom G.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Optics (physics.optics)
subject: General Physics (physics.gen-ph)
subject: FOS: Physical sciences

description: The dyadic Green function for a homogeneous electromagnetic medium inspired by the spatiotemporally nonhomogeneous constitutive equations of gravitationally affected vacuum is derived.
description: With corrected eqns (24) and (27)-(30)
Quantum state complexity meets many-body scars
Creators: name: Nandy, Sourav
name: Mukherjee, Bhaskar
name: Bhattacharyya, Arpan
name: Banerjee, Aritra
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Scar eigenstates in a many-body system refers to a small subset of non-thermal finite energy density eigenstates embedded into an otherwise thermal spectrum. This novel non-thermal behaviour has been seen in recent experiments simulating a one-dimensional PXP model with a kinetically-constrained local Hilbert space realized by a chain of Rydberg atoms. We probe these small sets of special eigenstates starting from particular initial states by computing the spread complexity associated to time evolution of the PXP hamiltonian. Since the scar subspace in this model is embedded only loosely, the scar states form a weakly broken representation of the Lie Algebra. We demonstrate why a careful usage of the Forward Scattering Approximation (or similar strategies thereof) is required to extract an appropriate set of Lanczos coefficients in this case as the consequence of this approximate symmetry. This leads to a well defined notion of a closed Krylov subspace and consequently, that of spread complexity. We show how the spread complexity shows approximate revivals starting from both $|\mathbb{Z}_2\rangle$ and $|\mathbb{Z}_3\rangle$ states and how these revivals can be made more accurate by adding optimal perturbations to the bare Hamiltonian. We also investigate the case of the vacuum as the initial state, where revivals can be stabilized using an iterative process of adding few-body terms.
description: 19 pages, 11 figures
Fourier Transformer: Fast Long Range Modeling by Removing Sequence Redundancy with FFT Operator
Creators: name: He, Ziwei
name: Yang, Meng
name: Feng, Minwei
name: Yin, Jingcheng
name: Wang, Xinbing
name: Leng, Jingwen
name: Lin, Zhouhan
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computation and Language (cs.CL)
subject: FOS: Computer and information sciences

description: The transformer model is known to be computationally demanding, and prohibitively costly for long sequences, as the self-attention module uses a quadratic time and space complexity with respect to sequence length. Many researchers have focused on designing new forms of self-attention or introducing new parameters to overcome this limitation, however a large portion of them prohibits the model to inherit weights from large pretrained models. In this work, the transformer's inefficiency has been taken care of from another perspective. We propose Fourier Transformer, a simple yet effective approach by progressively removing redundancies in hidden sequence using the ready-made Fast Fourier Transform (FFT) operator to perform Discrete Cosine Transformation (DCT). Fourier Transformer is able to significantly reduce computational costs while retain the ability to inherit from various large pretrained models. Experiments show that our model achieves state-of-the-art performances among all transformer-based models on the long-range modeling benchmark LRA with significant improvement in both speed and space. For generative seq-to-seq tasks including CNN/DailyMail and ELI5, by inheriting the BART weights our model outperforms the standard BART and other efficient models. \footnote{Our code is publicly available at \url{https://github.com/LUMIA-Group/FourierTransformer}}
A zero-inflated gamma model for deconvolved calcium imaging traces
Creators: name: Wei, Xue-Xin
name: Zhou, Ding
name: Grosmark, Andres
name: Ajabi, Zaki
name: Sparks, Fraser
name: Zhou, Pengcheng
name: Brandon, Mark
name: Losonczy, Attila
name: Paninski, Liam
Publisher: name: arXiv
Year: 2020
Subjects: subject: Neurons and Cognition (q-bio.NC)
subject: Machine Learning (stat.ML)
subject: FOS: Biological sciences
subject: FOS: Computer and information sciences

description: Calcium imaging is a critical tool for measuring the activity of large neural populations. Much effort has been devoted to developing "pre-processing" tools for calcium video data, addressing the important issues of e.g., motion correction, denoising, compression, demixing, and deconvolution. However, statistical modeling of deconvolved calcium signals (i.e., the estimated activity extracted by a pre-processing pipeline) is just as critical for interpreting calcium measurements, and for incorporating these observations into downstream probabilistic encoding and decoding models. Surprisingly, these issues have to date received significantly less attention. In this work we examine the statistical properties of the deconvolved activity estimates, and compare probabilistic models for these random signals. In particular, we propose a zero-inflated gamma (ZIG) model, which characterizes the calcium responses as a mixture of a gamma distribution and a point mass that serves to model zero responses. We apply the resulting models to neural encoding and decoding problems. We find that the ZIG model outperforms simpler models (e.g., Poisson or Bernoulli models) in the context of both simulated and real neural data, and can therefore play a useful role in bridging calcium imaging analysis methods with tools for analyzing activity in large neural populations.
description: Accepted for publication in Neurons, Behavior, Data analysis, and Theory
Mediating and negotiating culture in an art museum
Creators: name: Dent, Sandra
Publisher: name: University of British Columbia
Year: 2009

description: Cross cultural education in art museums is an interesting and complex issue. While cultural exhibitions have received attention in research, studies have usually focused on the nature of the exhibitions and have not explored the audience's understanding about culture in relationship to the exhibition. This qualitative study explores how and what First Nations cultures have been mediated by a civic art museum and negotiated by the museum audience, and the relationship between the two. Observations of the exhibition and audience and interviews with 99 adults in the museum were collected and analyzed to identify patterns and relationships. Analysis of the exhibition found the mediation of culture was distinguished by a partnership of the museum and First Nations cultures which reflected both their languages and voices. Audience responses illustrated a range of affective, factual and conceptual responses. Positive affective responses reflected the stimulation and satisfaction with learning which occurred. Visitors indicated enlightenment, exposure and revision of previously held ideas and assumptions, similarities and differences among cultures, and insight into perspectives of others. Partnership between the museum and the exhibition of masks from Northwest First Nations cultures is seen as a complex undertaking requiring reflection and examination of these two cultures. Visitor responses to the exhibition indicates learning, thinking and innumerable ways individuals construct meanings and understanding from art museum experiences.
Anisotropy, inhomogeneity and inertial range scalings in turbulent convection
Creators: name: Rincon, Francois
Publisher: name: arXiv
Year: 2006
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: This paper provides a detailed study of scale-by-scale budgets in turbulent Rayleigh-Bénard convection and aims at testing the applicability of Kolmogorov (1941) and Bolgiano (1959) theories for this flow. Particular emphasis is laid on anisotropic and inhomogeneous effects: the SO(3) decomposition of structure functions (Arad et al 1999) and a method of description of inhomogeneities proposed by Danaila et al (2001) are used to derive inhomogeneous and anisotropic generalizations of Kolmogorov and Yaglom equations applying to RB convection. The various terms in these equations are computed using data from a DNS of turbulent Boussinesq convection at $\rayleigh=10^6$ and $\prandtl=1$ with aspect ratio A=5. The analysis of the isotropic component demonstrates that the shape of the third-order velocity structure function is significantly influenced by buoyancy forcing and large-scale inhomogeneities, while the mixed third-order structure function appearing in Yaglom equation exhibits a clear scaling exponent 1 in a small range of scales. The magnitudes of the various low $\ell$ degree anisotropic components of the equations are also estimated and are shown to be comparable to their isotropic counterparts at moderate to large scales. Finally, a qualitative analysis shows that the influence of buoyancy forcing at scales smaller than the Bolgiano scale is likely to remain important up to $\rayleigh=10^9$, thus preventing Kolmogorov scalings from showing up in convective flows at lower Rayleigh numbers.
description: 28 pages, 18 figures, accepted for publication in J. Fluid Mech
Acronicta aceris
Creators: name: Joos, R Enato
name: Fritsch, Dieter
name: Bryner, Rudolf
name: Billen, Wolfgang
name: Wicki, Christoph
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Lepidoptera
Noctuidae
Acronicta
Acronicta aceris

description: 8778 Acronicta aceris (Linnaeus, 1758)
Basel (BS), Hörnli, 21.5.2014. Von der eher lokal verbreiteten Art sind in der Region seit 1980 nur wenige Nachweise bekannt.
description: Published as part of Joos, R Enato, Fritsch, Dieter, Bryner, Rudolf, Billen, Wolfgang & Wicki, Christoph, 2018, Vielfalt der nachtaktiven Gross- und Kleinschmetterlinge in zwei Parkanlagen bei Basel, pp. 57-71 in Entomo Helvetica 11 on page 62, DOI: 10.5169/seals-986024, http://zenodo.org/record/8034307
STATE TRADING ENTERPRISES IN A DIFFERENTIATED ENVIRONMENT: THE CASE OF GLOBAL MALTING BARLEY MARKETS
Creators: name: Dong, Fengxia
name: Marsh, Thomas L.
name: Stiegert, Kyle W.
name: Dong, Fengxia
name: Marsh, Thomas L.
name: Stiegert, Kyle W.
Publisher: name: Unknown
Year: 2003
Subjects: subject: Crop Production/Industries
subject: Marketing
subject: FOS: Economics and business
subject: malting barley
subject: market structure
subject: prepayment system
subject: product differentiation
subject: rent shifting
subject: state trading enterprises (STEs).

description: The lack of transparency in the pricing and operational activities of state trading enterprises (STEs) has caused members of the World Trade Organization to express concern that certain countries' STEs might circumvent Uruguay Round commitments on export subsidies, domestic support, or market access. The purpose of this study is to examine the market structure of the differentiated world malting barley market in which two STEs (the Canadian Wheat Board and the Australian Barley Board) maintain jointly a very large share of the export market. In particular, this study focuses on the exclusive procuring and pricing policies used by both STEs to test if these intra-country mechanisms can generate leadership and shift rent from other exporting countries. A conceptual and empirical framework is also provided to test if STEs set their initial payments at optimal levels. The study suggests that two STEs and other exporting countries were in Cournot competition. While some distortionary impacts from the STE prepayment systems are possible, it does not appear to be a tool that either STE employs. Empirical results from the precommitment stage show that the two STEs did not set their initial payments low enough to maximize their profits.
Near Unity Molecular Doping Efficiency in Monolayer MoS2
Creators: name: Yarali, Milad
name: Zhong, Yiren
name: Reed, Serrae N.
name: Wang, Juefan
name: Ulman, Kanchan A.
name: Charboneau, David J.
name: Curley, Julia B.
name: Hynek, David J.
name: Pondick, Joshua V.
name: Yazdani, Sajad
name: Hazari, Nilay
name: Quek, Su Ying
name: Wang, Hailiang
name: Cha, Judy J.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Surface functionalization with organic electron donors (OEDs) is an effective doping strategy for two-dimensional (2D) materials, which can achieve doping levels beyond those possible with conventional electric field gating. While the effectiveness of surface functionalization has been demonstrated in many 2D systems, the doping efficiencies of OEDs have largely been unmeasured, which is in stark contrast to their precision syntheses and tailored redox potentials. Here, using monolayer MoS2 as a model system and an organic reductant based on 4,4-bipyridine (DMAP-OED) as a strong organic dopant, we establish that the doping efficiency of DMAP-OED to MoS2 is in the range of 0.63 to 1.26 electrons per molecule. We also achieve the highest doping level to date in monolayer MoS2 by surface functionalization and demonstrate that DMAP-OED is a stronger dopant than benzyl viologen, which was the previous best OED dopant. The measured range of the doping efficiency is in good agreement with the values predicted from first-principles calculations. Our work provides a basis for the rational design of OEDs for high-level doping of 2D materials.
description: 19 pages, 4 figures, 1 table
R-Process Nucleosynthesis in MHD Jet Explosions of Core-Collapse Supernovae
Creators: name: Nishimura, Sunao
name: Kotake, Kei
name: Hashimoto, Masa-aki
name: Yamada, Shoichi
name: Nishimura, Nobuya
name: Fujimoto, Shinichiro
name: Sato, Katsuhiko
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We investigate $r$-process nucleosynthesis during the magnetohydrodynamical (MHD) explosion of supernova in a massive star of 13 $M_{\odot}$. Contrary to the case of the spherical explosion, jet-like explosion due to the combined effects of the rotation and magnetic field lowers the electron fraction significantly inside the layers above the iron core. We find that the ejected material of low electron fraction responsible for the $r$-process comes out from the silicon rich layer of the presupernova model. This leads to the production up to the third peak in the solar $r$-process elements. We examine whether the fission affects the $r$-process paths by using the full nuclear reaction network with both the spontaneous and $β$-delayed fission included. Moreover, we pay particular attention how the mass formula affects the $r$-process peaks with use of two mass formulae. It is found that both formulae can reproduce the global abundance pattern up to the third peak though detailed distributions are rather different. We point out that there are variations in the $r$-process nucleosynthesis if the MHD effects play an important role in the supernova explosion.
description: 19 pages with 7 figures, submitted to ApJ
"I feel therefore I am" : selected British and Canadian senior high school students’ conceptions of music and music education
Creators: name: Thompson, Joan Kathleen
Publisher: name: University of British Columbia
Year: 2009

description: The research reported in this text addresses the need to know how high school students interact with and construct meaning from their experiences with music. Taking its cue from the academic discourse and research that has proposed that the meaning of texts arises through reading and is mediated by a myriad of contextual influences, this research explores the individual and educational confluences of musical belief in the worlds of senior high school students in England and British Columbia, Canada. Guided by ethnographic research techniques, the findings of this multi-site case study are largely informed by interviews with 68 senior high school students; 35 in England and 33 in British Columbia, Canada. Attention to the role music plays in the lives of students in this study has brought to light a multiplicity of interpretations: those that are bounded by the features of adolescence and those that are sensitive to pervasive educational and cultural norms. Music's perceived power to arrest the senses, to communicate a depth of emotion and to transfigure reality appears to characterize these respondents' responses to music, triggering a narrative impulse that acts to synthesize the musical experience and integrate it within their lives. In combination with these adolescents' romantic sensibility, music takes on an allegorical function for them, symbolizing their desires for liberty, honesty, mystery and hope. The extent to which students' allegorical constructions of music's meaning are permitted to dominate their conceptions of it depends largely on the educational and cultural context in which they develop. Students' passionate attachment to music as a prompt for narrativizing and as a vehicle for self-realization is reinforced by the romantic values of popular culture in both countries, and for the Canadian students, the human-centric focus of music education practices in British Columbia. More entrenched artistic traditions in Europe and an educational system that promotes specialization in a field before high school graduation appear to diffuse students' romantic attachments to music. In addition to investing music with a narrative significance, many British students also come to see music as a significant art form and cultural resource. This study's bi-cultural comparison of adolescent interpretations of music may provoke music educators and scholars to consider how literal (music-centric) and rhetorical (humancentric) conceptions of music education could be broadened in order that learners' conceptions of music, and ultimately, of themselves, might be simultaneously engaged and challenged.