cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Distinct Degrees and Their Distribution in Complex Networks
Creators: name: Krapivsky, P. L.
name: Redner, S.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences

description: We investigate a variety of statistical properties associated with the number of distinct degrees that exist in a typical network for various classes of networks. For a single realization of a network with N nodes that is drawn from an ensemble in which the number of nodes of degree k has an algebraic tail, N_k ~ N/k^nu for k>>1, the number of distinct degrees grows as N^{1/nu}. Such an algebraic growth is also observed in scientific citation data. We also determine the N dependence of statistical quantities associated with the sparse, large-k range of the degree distribution, such as the location of the first hole (where N_k=0), the last doublet (two consecutive occupied degrees), triplet, dimer (N_k=2), trimer, etc.
description: 12 pages, 6 figures, iop format. Version 2: minor corrections
XUV exposed, non-hydrostatic hydrogen-rich upper atmospheres of terrestrial planets II: Hydrogen coronae and ion escape
Creators: name: Kislyakova, K. G.
name: Lammer, H.
name: Holmström, M.
name: Panchenko, M.
name: Odert, P.
name: Erkaev, N. V.
name: Leitzinger, M.
name: Khodachenko, M. L.
name: Kulikov, Yu. N.
name: Güdel, M.
name: Hanslmeier, A.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We study the interactions between the stellar wind plasma flow of a typical M star, such as GJ 436, and hydrogen-rich upper atmospheres of an Earth-like planet and a "super-Earth" with the radius of 2 R_Earth and a mass of 10 M_Earth, located within the habitable zone at ~0.24 AU. We investigate the formation of extended atomic hydrogen coronae under the influences of the stellar XUV flux (soft X-rays and EUV), stellar wind density and velocity, shape of a planetary obstacle (e.g., magnetosphere, ionopause), and the loss of planetary pick-up ions on the evolution of hydrogen-dominated upper atmospheres. Stellar XUV fluxes which are 1, 10, 50 and 100 times higher compared to that of the present-day Sun are considered and the formation of high-energy neutral hydrogen clouds around the planets due to the charge-exchange reaction under various stellar conditions have been modeled. Charge-exchange between stellar wind protons with planetary hydrogen atoms, and photoionization, leads to the production of initially cold ions of planetary origin. We found that the ion production rates for the studied planets can vary over a wide range, from ~1.0x10^{25} s^{-1} to ~5.3x10^{30} s^{-1}, depending on the stellar wind conditions and the assumed XUV exposure of the upper atmosphere. Our findings indicate that most likely the majority of these planetary ions are picked up by the stellar wind and lost from the planet. Finally, we estimate the long-time non-thermal ion pick-up escape for the studied planets and compare them with the thermal escape. According to our estimates, non-thermal escape of picked up ionized hydrogen atoms over a planet's lifetime varies between ~0.4 Earth ocean equivalent amounts of hydrogen (EO_H) to <3 EO_H and usually is several times smaller in comparison to the thermal atmospheric escape rates.
description: 53 pages, 6 figures, 10 tables, submitted to Astrobiology
Estimations of the magnetic field strength in the torus of AGN using near-infrared polarimetry
Creators: name: Lopez-Rodriguez, E.
name: Packham, C.
name: Young, S.
name: Elitzur, M.
name: Levenson, N. A.
name: Mason, R. E.
name: Almeida, C. Ramos
name: Alonso-Herrero, A.
name: Jones, T. J.
name: Perlman, E.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: An optically and geometrically thick torus obscures the central engine of Active Galactic Nuclei (AGN) from some lines of sight. From a magnetohydrodynamical framework, the torus can be considered to be a particular region of clouds surrounding the central engine where the clouds are dusty and optically thick. In this framework, the magnetic field plays an important role in the creation, morphology and evolution of the torus. If the dust grains within the clouds are assumed to be aligned by paramagnetic alignment, then the ratio of the intrinsic polarisation and visual extinction, P(%)/Av, is a function of the magnetic field strength. To estimate the visual extinction through the torus and constrain the polarisation mechanisms in the nucleus of AGN, we developed a polarisation model to fit both the total and polarised flux in a 1.2" (~263pc) aperture of the type 2 AGN, IC5063. The polarisation model is consistent with the nuclear polarisation observed at K being produced by dichroic absorption from aligned dust grains with a visual extinction through the torus of 48$\pm$2 mag. We estimated the intrinsic polarisation arising from dichroic absorption to be P$_{K}^{dic}$=12.5$\pm$2.7%. We consider the physical conditions and environment of the gas and dust for the torus of IC5063. Then, through paramagnetic alignment, we estimate a magnetic field strength in the range of 12-128mG in the NIR emitting regions of the torus of IC5063. Alternatively, we estimate the magnetic field strength in the plane of the sky using the Chandrasekhar-Fermi method. The minimum magnetic field strength in the plane of the sky is estimated to be 13 and 41 mG depending of the conditions within the torus of IC5063. These techniques afford the chance to make a survey of AGN, to investigate the effects of magnetic field strength on the torus, accretion, and interaction to the host galaxy.
description: Accepted by MNRAS, 16 pages, 10 figures, 6 tables
Galaxy rotation curves. The theory
Creators: name: Meierovich, Boris E.
Publisher: name: arXiv
Year: 2013
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The non-gauge vector field with as simple as possible Lagrangian (\ref{Lagrangian}) turned out an adequate tool for macroscopic description of the main properties of dark matter. The dependence of the velocity of a star on the radius of the orbit $V\left(r\right) $ -- galaxy rotation curve -- is derived analytically from the first principles\ completely within the Einstein's general relativity. The Milgrom's empirical modification of Newtonian dynamics in nonrelativistic limit (MOND) gets justified and specified in detail. In particular, the transition to a plateau is accompanied by damping oscillations. In the scale of a galaxy, and in the scale of the whole universe, the dark matter is described by a vector field with the same energy-momentum tensor. It is the evidence of the common physical nature. Now, when we have the general expression (\ref{Tik b=c=0}) for the energy-momentum tensor of dark matter, it is possible to analyze its influence on the structure and evolution of super heavy stars and black holes.
description: 17 pages, 13 figures
Investigation of pollen cell fate determination in Arabidopsis thaliana
Creators: name: Hasan, Ghazwan Q.
Publisher: name: University of Leicester
Year: 2021
Subjects: Uncategorized

description: The aim of the work is to investigate how asymmetric cell division and cell lineage isolation are linked to pollen cell fate determination. This was analysed by monitoring the activation of vegetative and male germline-specific markers in mutants, which disturb microspore polarity and division asymmetry (gemini pollen 1), or which disturb cytokinesis and cell lineage isolation (two-in-one). In twin-celled equally divided pollen present in late bicellular and mature anthers, the activation of VCK promoter was expressed in both daughter cells, while the activation of DUO1 and HTR10 promoters were not expressed at any stages. The centromeric chromatin fate marker HTR12-GFP is present at discrete nuclear foci in generative cell and sperm cell nuclei in wild type pollen, while in gem1 equal daughter cells the marker was initially detected in foci, but later was dispersed. Further, transposable elements activation represented by GUS reporter activity was present in wild type, twin-celled and binucleate pollen. These results support the hypothesis that asymmetric division of the microspore is required for the specification of generative cell fate and differential centromere identity between vegetative and generative cell nuclei. The analysis of cell fate in tio mutants showed that isolation of the germ cell lineage is not required for the initial activation of generative cell fate, but is essential for the maintenance of differential centromere identity. In binucleate tio pollen, generative cell fate markers were expressed despite the failure to partition daughter nuclei into separate cells. Three different cell fate categories were observed among binucleate tio pollen, including pollen with vegetative cell fate only, generative cell fate only and pollen with mixed cell fate. Moreover, the centromeric fate marker was initially present at discrete nuclear foci in both nuclei of binucleate tio pollen and later was dispersed. In a study of MICROTUBULE ORGANIZATION1 (MOR1) fused to YFP, the protein was localised as a perinuclear signal in microspores and enriched in the male germline of wild type pollen, while MOR1-YFP was not expressed in mutant gem1 and tio pollen.
A study of porous metal cooling
Creators: name: Hoffman, Charles Calvin
name: Gillette, Edmond Stephen
Publisher: name: California Institute of Technology
Year: 1946
Subjects: Aeronautics
Aeronautical Engineering

description: This investigation was conducted to study the flow rate necessary to maintain a sweat cooled metal at an equilibrium temperature when subjected to a high gas temperature. The study was limited to fundamental tests on copper, bronze, and stainless steel porous metal specimens which were the only types available at this time. Water cooling was used throughout the investigation.

Conclusions of a qualitative nature were obtained which show that water flow rate is a primary factor in maintaining sweat cooled metals at equilibrium temperature, and that metal thermal conductivity has but slight effect. The feasibility of the sweat cooling technique was proven by the fact that a water flow rate of less than 0.1 cc/in.^2-sec was required to satisfactorily cool a porous metal surface subjected to a potential heat transfer of 1.0 BTU/in.^2-sec.
Compressive X-ray phase tomography based on the transport of intensity equation
Creators: name: Tian, Lei
name: Petruccelli, Jonathan C.
name: Miao, Qin
name: Kudrolli, Haris
name: Nagarkar, Vivek
name: Barbastathis, George
Publisher: name: arXiv
Year: 2013
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We develop and implement a compressive reconstruction method for tomographic recovery of refractive index distribution for weakly attenuating objects in a microfocus X-ray system. This is achieved through the development of a discretized operator modeling both the transport of intensity equation and X-ray transform that is suitable for iterative reconstruction techniques.
Emerging investigator series: thermodynamic and energy analysis of nitrogen and phosphorous recovery from wastewaters
Creators: name: McCartney, Stephanie Nicole
name: Watanabe, Nobuyo S.
name: Yip, Ngai Yin
Publisher: name: Columbia University
Year: 2021
Subjects: subject: Water reuse
subject: Water--Management
subject: Thermodynamics
subject: Environmental engineering
subject: FOS: Environmental engineering

description: In a circular nutrient economy, nitrogen and phosphorous are removed from waste streams and captured as valuable fertilizer products, to more sustainably reuse the resources in closed-loops and simultaneously protect receiving aquatic environments from harmful N and P emissions. For nutrient reclamation to be competitive with the existing practices of N fixation and P mining, the methods of recovery must achieve at least comparable energy consumption. This study employed the Gibbs free energy of separation to quantify the minimum energy required to recover various N and P fertilizer products from waste streams of fresh and hydrolyzed urine, greywater, domestic wastewater, and secondary treated wastewater effluent. The comparative advantages in theoretical energy intensities for N and P recovery from nutrient-dense waste streams, such as fresh and hydrolyzed urine, were assessed against the other more dilute sources. For example, compared to reclaiming the nutrients from treated wastewater effluent at centralized wastewater treatment plants, the minimum energy required to recover 1.0 M NH3(aq) from source-separated hydrolyzed urine can be ≈40–68% lower, whereas recovering KH2PO4(s) from diverted fresh urine can, in principle, be ≈13–34% less energy intensive. The study also evaluated the efficiencies required by separation techniques for the energy demand of N and P recovery to be lower than the current production approaches of the Haber–Bosch process and phosphate rock mining. For instance, the most energetically favorable ammoniacal nitrogen and orthophosphate reclamation schemes, which target hydrolyzed and fresh urine, respectively, require energy efficiencies >7% and >39%. This study highlights that strategic selection of waste stream and fertilizer product can enable the most expedient recovery of nutrients and realize a circular economy model for N and P management.
A class of random fields on complete graphs with tractable partition function
Creators: name: Flach, Boris
Publisher: name: arXiv
Year: 2012
Subjects: subject: Machine Learning (cs.LG)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: The aim of this short note is to draw attention to a method by which the partition function and marginal probabilities for a certain class of random fields on complete graphs can be computed in polynomial time. This class includes Ising models with homogeneous pairwise potentials but arbitrary (inhomogeneous) unary potentials. Similarly, the partition function and marginal probabilities can be computed in polynomial time for random fields on complete bipartite graphs, provided they have homogeneous pairwise potentials. We expect that these tractable classes of large scale random fields can be very useful for the evaluation of approximation algorithms by providing exact error estimates.
description: accepted for publication in IEEE TPAMI (short paper)
Determination of Non-Metals by Molecular Absorption: A Minireview from the Beginning through Recent Developments in High-Resolution Continuum Source Molecular Absorption Spectrometry (HR-CS MAS)
Creators: name: Souza, Lilian Rodrigues Rosa
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Biophysics
subject: Biochemistry
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: FOS: Biological sciences
subject: Sociology
subject: FOS: Sociology
subject: Cancer
subject: Science Policy

description: The determination of nonmetals via molecular absorption spectrometry (MAS) began in the 1970s using conventional atomic absorption spectrometry with a line source. However, due to low resolution and spectral interferences, these measurements were improved by the development of the high-resolution continuum source that provides information about the spectral environment. Hence, here is reviewed formative studies on the determination of nonmetals as well as the state of the art of this approach. This review presents the fundamentals of the MAS involving the determination of S, P, Cl, F, and Br, and the cutting-edge research such as isotopic determination via MAS.
Electrochemical Point-of Care (PoC) Determination of Interleukin-6 (IL-6) Using a Pyrrole (Py) Molecularly Imprinted Polymer (MIP) on a Carbon-Screen Printed Electrode (C-SPE)
Creators: name: de Lurdes Gonçalves, M.
name: Truta, Liliana A. N.
name: Sales, M. Goreti F.
name: Moreira, Felismina T. C.
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Space Science
subject: Medicine
subject: Molecular Biology
subject: Neuroscience
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: Cancer

description: Here is presented a highly sensitive biomimetic sensor for the detection of an Alzheimer’s Disease (AD) biomarker, interleukin-6 (IL6), for point-of-care (PoC) analysis. The imprinted polymeric film was prepared by the co-electropolymerization of pyrrole (Py) and carboxylated pyrrole in the presence of IL6, on a carbon-screen printed electrode . The biomarker molecule was then removed by oxalic acid , creating the recognition vacant sites. Similarly, a control was also prepared in absense of the IL6 biomarker . The different steps of the sensor fabrication were characterized by Raman Spectroscopy, Electrochemical Impedance Spectroscopy (EIS), and Cyclic Voltammetry. Biomarker recognition and capture capacity of the sensing material was measured by EIS. The biomimetic sensor showed a limit of detection for IL6 of 0.02 pg/mL in spiked serum samples. Overall, the biosensing device showed good sensitivity, reproducibility, accuracy, and rapid response time, which contibute for the development of early diagnostics Poc tools for neurological diseases.
dc conductivity as a geometric phase
Creators: name: Hetényi, Balázs
Publisher: name: arXiv
Year: 2012
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: Mathematical Physics (math-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The zero frequency conductivity ($D_c$), the criterion to distinguish between conductors and insulators is expressed in terms of a geometric phase. $D_c$ is also expressed using the formalism of the modern theory of polarization. The tenet of Kohn [{\it Phys. Rev.} {\bf 133} A171 (1964)], namely, that insulation is due to localization in the many-body space, is refined as follows. Wavefunctions which are eigenfunctions of the total current operator give rise to a finite $D_c$ and are therefore metallic. They are also delocalized. Several examples which corroborate the results are presented, as well as a numerical implementation. The formalism is also applied to the Hall conductance, and the quantization condition for zero Hall conductance is derived to be $\frac{eΦ_B}{N h c} = \frac{Q}{M}$, with $Q$ and $M$ integers.
description: minor changes compared to previous version, and reference added
Simultaneous Determination of the Acid Dissociation Constants of Phenolics by Multivariate Analysis of pH and Ultraviolet-Visible Spectrophotometric Measurements
Creators: name: Dinç, Erdal
name: Selimoğlu, Faysal
name: Ünal, Nazangül
name: Ertekin, Zehra Ceren
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Biochemistry
subject: Space Science
subject: Medicine
subject: Microbiology
subject: FOS: Biological sciences
subject: Pharmacology
subject: Biotechnology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Sociology
subject: FOS: Sociology
subject: 69999 Biological Sciences not elsewhere classified
subject: 80699 Information Systems not elsewhere classified
subject: FOS: Computer and information sciences
subject: Cancer
subject: Hematology
subject: 110309 Infectious Diseases
subject: FOS: Health sciences
subject: Plant Biology

description: In the development of new commercial products in the pharmaceutical and food industries, acid dissociation constant (Ka) values of active and inactive ingredients are important factors for the estimation of the biological activity. In this regard, new spectrophotometric approaches based on parallel factor analysis (PARAFAC) and multivariate curve resolution-alternating least squares (MCR-ALS) to pH-absorbance dataset are described for the simultaneous determination of the acid dissociation constants of the phenolics ferulic acid, 4-hydroxybenzoic acid, syringic acid, protocatechuic acid, vanillic acid, and isovanillic acid that have more than one dissociation equilibrium without using classical titration procedures. The acid dissociation constants were determined by the pH profiles obtained by bilinear MCR-ALS and trilinear PARAFAC decomposition of pH-ultraviolet and pH-ultraviolet-visible spectroscopic datasets of the phenolics. For the quantification of the acid dissociation constants with the MCR-ALS and PARAFAC approaches, the estimated spectral profiles provided an opportunity for the direct observation of the individual spectral bands of each phenolic without the use of additional software. The results showed that MCR-ALS and PARAFAC applications to spectrophotometric measurements at various pH values were alternatives for solving acid dissociation constant problems that cannot be determined by classical methods.
Magnetic Domain Structure of La0.7Sr0.3MnO3 thin-films probed at variable temperature with Scanning Electron Microscopy with Polarization Analysis
Creators: name: Reeve, Robert M.
name: Mix, Christian
name: König, Markus
name: Foerster, Michael
name: Jakob, Gerhard
name: Kläui, Mathias
Publisher: name: arXiv
Year: 2013
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The domain configuration of 50 nm thick La0.7SrMnO3 films has been directly investigated using scanning electron microscopy with polarization analysis (SEMPA), with magnetic contrast obtained without the requirement for prior surface preparation. The large scale domain structure reflects a primarily four-fold anisotropy, with a small uniaxial component, consistent with magneto-optic Kerr effect measurements. We also determine the domain transition profile and find it to be in agreement with previous estimates of the domain wall width in this material. The temperature dependence of the image contrast is investigated and compared to superconducting-quantum interference device magnetometry data. A faster decrease in the SEMPA contrast is revealed, which can be explained by the technique's extreme surface sensitivity, allowing us to selectively probe the surface spin polarization which due to the double exchange mechanism exhibits a distinctly different temperature dependence than the bulk magnetization.
Statistics of a quantum-state-transfer Hamiltonian in the presence of disorder
Creators: name: Nikolopoulos, Georgios M.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We present a statistical analysis on the performance of a protocol for the faithful transfer of a quantum state in finite qubit or spin chains, in the presence of diagonal and off-diagonal disorder. It is shown that the average-state fidelity, typically employed in the literature for the quantification of the transfer, may overestimate considerably the performance of the protocol in a single realization, leading to faulty conclusions about the success of the transfer.
The Dependence of Star Formation Efficiency on Gas Surface Density
Creators: name: Burkert, Andreas
name: Hartmann, Lee
Publisher: name: arXiv
Year: 2012
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Studies by Lada (2010) and Heiderman (2010) have suggested that star formation mostly occurs above a threshold in gas surface density Sigma of Sigma_c = 120 Msun pc^{-2} (A_K = 0.8). Heiderman infer a threshold by combining low-mass star-forming regions, which show a steep increase in the star formation rate per unit area Sigma_SFR with increasing Sigma, and massive cores forming luminous stars which show a linear relation. We argue that these observations do not require a particular density threshold. The steep dependence of Sigma_SFR, approaching unity at protostellar core densities, is a natural result of the increasing importance of self-gravity at high densities along with the corresponding decrease in evolutionary timescales. The linear behavior of Sigma_SFR vs. Sigma in massive cores is consistent with probing dense gas in gravitational collapse, forming stars at a characteristic free-fall timescale given by the use of a particular molecular tracer. The low-mass and high-mass regions show different correlations between gas surface density and the area A spanned at that density, with A=Sigma^{-3} for low-mass regions and A=Sigma^{-1} for the massive cores; this difference, along with the use of differing techniques to measure gas surface density and star formation, suggests that connecting the low-mass regions with massive cores is problematic. We show that the approximately linear relationship between dense gas mass and stellar mass used by Lada similarly does not demand a particular threshold for star formation, and requires continuing formation of dense gas. Our results are consistent with molecular clouds forming by galactic hydrodynamic flows with subsequent gravitational collapse.
description: 15 pages, 11 figures, ApJ, in press
Fluxes of Courant bracket twisted at the same time by $B$ and $θ$
Creators: name: Davidović, Ljubica
name: Ivanišević, Ilija
name: Sazdović, Branislav
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: This paper investigates the simultaneous twisting of the Courant bracket by a 2-form $B$ and a bi-vector $θ$, exploring the generalized fluxes obtained in Courant algebroid relations. We define the twisted Lie bracket and demonstrate that the generalized $H$-flux can be expressed as the field strength defined on this Lie algebroid. Similarly, we show that the $f$-flux is a direct consequence of simultaneous twisting, which arises in the twisted Lie bracket relations between holonomic partial derivatives. We obtain the generalized $Q$ flux in terms of the twisted Koszul bracket, which is a quasi-Lie algebroid bracket. The action of an exterior derivative related to the twisted Koszul bracket on a bi-vector produces the generalized $R$-flux. We show that the generalized $R$-flux is also the twisted Schouten-Nijenhuis bracket, i.e. the natural graded bracket on multi-vectors defined with the twisted Lie bracket.
An arithmetic count of osculating lines
Creators: name: Muratore, Giosuè
Publisher: name: arXiv
Year: 2023
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14N15, 11E81, 14F42

description: We say that a line in $\mathbb P^{n+1}_k$ is osculating to a hypersurface $Y$ if they meet with contact order $n+1$. When $k=\mathbb C$, it is known that through a fixed point of $Y$, there are exactly $n!$ of such lines. Under some parity condition on $n$ and $\mathrm{deg}(Y)$, we define a quadratically enriched count of these lines over any perfect field $k$. The count takes values in the Grothendieck--Witt ring of quadratic forms over $k$ and depends linearly on $\mathrm{deg}(Y)$.
description: 21 pages, nyjm.albany.edu/j/2024/30-72.html
Classical and quantum Big Brake cosmology for scalar field and tachyonic models
Creators: name: Kamenshchik, A.
name: Manti, S.
Publisher: name: arXiv
Year: 2013
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study a relation between the cosmological singularities in classical and quantum theory, comparing the classical and quantum dynamics in some models possessing the Big Brake singularity - the model based on a scalar field and two models based on a tachyon-pseudo-tachyon field . It is shown that the effect of quantum avoidance is absent for the soft singularities of the Big Brake type while it is present for the Big Bang and Big Crunch singularities. Thus, there is some kind of a classical - quantum correspondence, because soft singularities are traversable in classical cosmology, while the strong Big Bang and Big Crunch singularities are not traversable.
description: 8 pages, published in the Proceedings of the International conference "Multiverse and Fundamental Cosmology: Multicosmofun '12", September 10-14, Szczein, Poland edited by Mariusz P. Dabrowski, Adam Balcerzak, Tomasz Denkiewicz
Ergodic behavior of products of random positive operators
Creators: name: Ligonnière, Maxime
Publisher: name: arXiv
Year: 2023
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics

description: This article is devoted to the study of products of random operators of the form $M_{0,n}=M_0\cdots M_{n-1}$, where $(M_{n})_{n\in\mathbb{N}}$ is an ergodic sequence of positive operators on the space of signed measures on a space $\mathbb{X}$. Under suitable conditions, in particular, a Doeblin-type minoration suited for non conservative operators, we obtain asymptotic results of the form \[ μM_{0,n} \simeq μ(\tilde{h}) r_n π_n,\] where $\tilde{h}$ is a random bounded function, $(r_n)_{n\geq 0}$ is a random non negative sequence and $π_n$ is a random probability measure on $\mathbb{X}$. Moreover, $\tilde{h}$, $(r_n)$ and $π_n$ do not depend on the choice of the measure $μ$. We prove additionally that $n^{-1} \log (r_n)$ converges almost surely to the Lyapunov exponent $λ$ of the process $(M_{0,n})_{n\geq 0}$ and that the sequence of random probability measures $(π_n)$ converges weakly towards a random probability measure. These results are analogous to previous estimates from Hennion in the case of $d\times d$ matrices, that were obtained with different techniques, based on a projective contraction in Hilbert distance. In the case where the sequence $(M_n)$ is i.i.d, we additionally exhibit an expression of the Lyapunov exponent $λ$ as an integral with respect to the weak limit of the sequence of random probability measures $(π_n)$ and exhibit an oscillation behavior of $r_n$ when $λ=0$. We provide a detailed comparison of our assumptions with the ones of Hennion and present some example of applications of our results, in particular in the field of population dynamics.
description: 43 pages. Comments and remarks are welcome !
Correlation of Fatigue Data to Determine Stress Concentration Factors in 76s-T Aluminum Alloys
Creators: name: Kane, John Clarence
Publisher: name: California Institute of Technology
Year: 1950
Subjects: Aeronautical engineering
Aeronautics

description: The purpose of this study was to determine the stress concentration factor in a shoulder under a cyclic tensile load. The test specimens were models of a propeller blade root section similar to the blade design now employed in the fans of the Cooperative Wind Tunnel. All specimens were given a 5 microinch finish and all were made of 76S-T aluminum alloy taken from an actual propeller blade forging. Two series of tests were conducted. One series consisted of a cyclic tensile load varying from zero to maximum over a nominal stress range from 21,000 psi to 28,000 psi. The other series consisted of a cyclic load, wherein the amplitude of the cyclic stress was varied from 20 to 50 percent of the maximum developed stress. These two conditions would correspond respectively to the "start-stop" cycle of wind tunnel operation and to constant speed tunnel operation.

It was found that the stress concentration factor determined from the fatigue test results closely approximated the results obtained from the three dimensional static tests of the actual blade.

This work was carried out by the authors at the Guggenheim Aeronautical Laboratory, California Institute of Technology, under the supervision of Dr. E. E. Sechler.
Electrochemical Determination of Levodopa and Cabergoline by a Magnetic Core-Shell Iron (II,III) Oxide@Silica/Multiwalled Carbon Nanotube/Ionic Liquid/2-(4-Oxo-3-Phenyl-3,4-Dihydroquinazolinyl)- N′-Phenyl-Hydrazine Carbothioamide (FSCNT/IL/2PHC) Modified Carbon Paste Electrode
Creators: name: Tajik, Somayeh
name: Garkani-Nejad, Zahra
name: Mahmoudi-Moghaddam, Hadi
name: Beitollahi, Hadi
name: Khabazzadeh, Hojatollah
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Biophysics
subject: Space Science
subject: Medicine
subject: Microbiology
subject: FOS: Biological sciences
subject: Biotechnology
subject: Sociology
subject: FOS: Sociology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: Inorganic Chemistry
subject: Science Policy
subject: Plant Biology

description: This study reports a highly selective and sensitive electrochemical technique for levodopa and cabegoline based on the enhanced electrochemical response to magnetic core-shell Fe3O4@SiO2/multiwalled carbon nanotubes nanocomposite/N-butylpyridinium hexafluorophosphate (as an ionic liquid [IL])/2-(4-oxo-3-phenyl-3,4-dihydroquinazolinyl)-N′-phenyl-hydrazine-carbothioamide (2PHC) modified carbon paste electrode (FSCNT/IL/2PHC/CPE). Therefore differential pulse voltammetry (DPV) and the cyclic voltammetry (CV) were utilized to examine the electrocatalysis of levodopa and cabergoline at the modified electrode. After optimizing the conditions, the sensor had favorable electrochemical responses toward levodopa and cabergoline. DPV indicated a significantly higher electrochemical signal for levodopa and cabergoline at the modified electrode, which provides the sensitivity of the sensor for the analytes. The peak current for levodopa was linear between 0.06 and 400.0 µM with a limit of detection of 0.02 µM. In addition, the modified CPE was used to determine cabergoline from 0.07 to 350.0 µM with a limit of detection of 0.019 µM. This sensor was employed to simultaneously determine cabergoline and levodopa in urine, serum, and pharmaceuticals.
An experimental investigation of wind tunnel wall interference on rolling and yawing moments due to deflected ailerons
Creators: name: Koch, Walter Louis
Publisher: name: California Institute of Technology
Year: 1940
Subjects: Aeronautics

description: Wind tunnel tests were made on a model wing with deflected ailerons in both open- and closed-jet configurations of a small wind tunnel.  Rolling and yawing moments and lift were measured at various angles of attack.  The wind tunnel wall interference on rolling and yawing moments is determined by comparison of the open- and closed-jet results.  An approximate comparison with available theories is included.  It appears that the interference effects measured are somewhat smaller than predicted by the theories.
Freeness of hyperplane arrangements and related topics
Creators: name: Yoshinaga, Masahiko
Publisher: name: arXiv
Year: 2012
Subjects: subject: Algebraic Geometry (math.AG)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: This is the expanded notes of the lecture by the author in "Arrangements in Pyrenees", June 2012. We are discussing relations of freeness and splitting problems of vector bundles, several techniques proving freeness of hyperplane arrangements, K. Saito's theory of primitive derivations for Coxeter arrangements, their application to combinatorial problems and related conjectures.
description: 28 pages
BFKL Pomeron: modeling confinement
Creators: name: Levin, Eugene
name: Tapia, Sebastian
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In this paper we introduce the confinement into the kernel of the BFKL equation,assuming that the sizes of produced dipoles cannot be large. The goal of this paper is to find how this assumption, which leads to a correct exponential decrease of the amplitude at large impact parameters, affects the main properties of the BFKL Pomeron. We solve the equations for total cross section and $\ $ numerically and developed some methods of analytical solutions. The main result is that the modified BFKL Pomeron has the same intercept and $α'_\pom = 0$ as the BFKL Pomeron.It gives us a hope that the unknown confinement will change only slightly the equations of the CGC/saturation approach
description: 22pp, 23 figures in .eps files
ASEXUAL MINORITY STRESS SCALE (AMSS): CONSTRUCTION AND VALIDATION
Creators: name: Rouvere, Julien
Publisher: name: Zenodo
Year: 2022
Subjects: asexuality
minority stress
item response theory
nominal response model
scale development
LGBTQIA

description: The majority of studies examining discrimination in the asexual population adapted existing measures intended for lesbian, gay, and bisexual (LGB) people. While these studies examined overlapping experiences of discrimination between asexual and LGB individuals, they failed to assess facets of minority stress unique to asexual people. Asexuality is defined as the lack of, or little, sexual attraction towards others. The goal of the current study was to develop the Asexual Minority Stress Scale (AMSS), a validated self-report measure that assesses minority stress factors experienced by the asexual population. The methodology was guided by phenomenological theory and the minority stress model. The study used an exploratory sequential design. Participants (n = 721) completed an intake survey, and six researchers conducted interviews with 23 asexual participants. A thematic analysis guided item development for the preliminary AMSS. In Study 2, data (n = 896, nasexual = 666) were analyzed using Item Response Theory (IRT) with the 2-parameter logistic and nominal response models to guide item retention and modification. The finalized AMSS comprised 49 items with four subscales (Distal Stressors, Proximal Stressors, Coping Factors, and Protective Factors). Study 3 involved examining the psychometric properties of the AMSS using IRT, validity analyses, and the assessment of several exploratory hypotheses. The AMSS had high reliability, content validity, and known-groups validity, excellent convergent validity for the Distal and Proximal Stressors subscales, and excellent incremental validity for the Coping Mechanisms and Protective Factors subscales. The AMSS is the first validated instrument for the asexual population developed using IRT and provides a comprehensive assessment of minority stress factors that impact disparate health outcomes for asexual people within the minority stress model.
Edge Union of Networks on the Same Vertex Set
Creators: name: Wen, Chuan
name: Loe
name: Jensen, Henrik Jeldtoft
Publisher: name: arXiv
Year: 2012
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Social and Information Networks (cs.SI)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Random networks generators like Erdoes-Renyi, Watts-Strogatz and Barabasi-Albert models are used as models to study real-world networks. Let G^1(V,E_1) and G^2(V,E_2) be two such networks on the same vertex set V. This paper studies the degree distribution and cluster coefficient of the resultant networks, G(V, E_1 U E_2).
description: 18 pages and 8 figures
The effect of quantum fluctuations on the coloring of random graphs
Creators: name: Bapst, Victor
name: Semerjian, Guilhem
name: Zamponi, Francesco
Publisher: name: arXiv
Year: 2013
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Computational Complexity (cs.CC)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: We present a study of the coloring problem (antiferromagnetic Potts model) of random regular graphs, submitted to quantum fluctuations induced by a transverse field, using the quantum cavity method and quantum Monte-Carlo simulations. We determine the order of the quantum phase transition encountered at low temperature as a function of the transverse field and discuss the structure of the quantum spin glass phase. In particular, we conclude that the quantum adiabatic algorithm would fail to solve efficiently typical instances of these problems because of avoided level crossings within the quantum spin glass phase, caused by a competition between energetic and entropic effects.
description: 28 pages, 17 figures
Assessing short-term effects of ambient air pollution on respiratory diseases in Guwahati, India with the application of the generalized additive model
Creators: name: Dutta, Abhishek
name: Jinsart, Wanida
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Medicine
subject: Biotechnology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Sociology
subject: FOS: Sociology
subject: Science Policy
subject: Computational Biology

description: Research studies connecting air pollution and its effect on health are much needed by the policymakers in India. Generalized additive model (GAM) was applied to quantify the effect of air pollutants on hospital visits related to respiratory diseases for an Indian city, Guwahati. A total of 6335 patients visited the only medical college and hospital in the city for respiratory diseases during 2016-2018. The multi-pollutant GAM models indicate the existence of synergistic effects of particulate matter less than 2.5 µm in diameter (PM2.5), nitrogen dioxide (NO2), and carbon monoxide (CO) on hospital visits of the patients due to respiratory diseases. The ambient PM2.5 concentrations have a strong link with hospital visits in all 6 single lag days. However, the effect of CO on hospital visits due to respiratory diseases was more robust. The percent change of hospital visits associated with each 1 unit increase in CO concentrations at lag 1 day was 15.7% (RR = 1.157; 95% CI 0.929, 1.442), which was enhanced to as high as 40.8% (RR = 1.408; 1.130,1.755) at lag3. The rise of each 10 units of concentrations of PM2.5 and 1 unit of CO at cumulative lag0-6 day was associated with the percentage change in hospital visits of 6.67% and 62.36% respectively. Single-pollutant GAM models indicate that the risk percentage of PM2.5 causing respiratory disease increased in combination with other pollutants.
A Terradynamics of Legged Locomotion on Granular Media
Creators: name: Li, Chen
name: Zhang, Tingnan
name: Goldman, Daniel I.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Fluid Dynamics (physics.flu-dyn)
subject: Quantitative Methods (q-bio.QM)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: The theories of aero- and hydrodynamics predict animal movement and device design in air and water through the computation of lift, drag, and thrust forces. Although models of terrestrial legged locomotion have focused on interactions with solid ground, many animals move on substrates that flow in response to intrusion. However, locomotor-ground interaction models on such flowable ground are often unavailable. We developed a force model for arbitrarily-shaped legs and bodies moving freely in granular media, and used this "terradynamics" to predict a small legged robot's locomotion on granular media using various leg shapes and stride frequencies. Our study reveals a complex but generic dependence of stresses in granular media on intruder depth, orientation, and movement direction and gives insight into the effects of leg morphology and kinematics on movement.
An investigation of the round jet in a moving air stream
Creators: name: Deodati, Joseph Benjamin
name: Monteath, Edward Berlendis
Publisher: name: California Institute of Technology
Year: 1947
Subjects: round jet
air stream
Aeronautics
Aeronautical Engineering

description: A theoretical investigation is made of a circular jet issuing from an orifice into an air stream flowing parallel to the jet axis and in the same direction as the jet. The analysis is divided into two portions:

1. The region immediately downstream of the orifice in which exists the potential cone of uniform velocity.
2. The region downstream of the end of the potential cone in which the jet is fully developed.

The solution for these two portions are fitted together at the section at which the potential cone disappears giving a complete solution for the whole jet.

Numerical computations are made for several ratios of free stream velocity to jet velocity to determine the spread of the jet, velocity on the axis of the jet, and spread of the surface on which the velocity is one half the sum of the jet velocity and free stream velocity.

Squire and Trouncer's results are plotted as a comparison with those obtained in this analysis.
Heterotic non-Abelian orbifolds
Creators: name: Fischer, Maximilian
name: Ramos-Sanchez, Saul
name: Vaudrevange, Patrick K. S.
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We perform the first systematic analysis of particle spectra obtained from heterotic string compactifications on non-Abelian toroidal orbifolds. After developing a new technique to compute the particle spectrum in the case of standard embedding based on higher dimensional supersymmetry, we compute the Hodge numbers for all recently classified 331 non-Abelian orbifold geometries which yield N=1 supersymmetry for heterotic compactifications. Surprisingly, most Hodge numbers follow the empiric pattern h^(1,1) - h^(2,1) = 0 mod 6, which might be related to the number of three standard model generations. Furthermore, we study the fundamental groups in order to identify the possibilities for non-local gauge symmetry breaking. Three examples are discussed in detail: the simplest non-Abelian orbifold S_3 and two more elaborate examples, T_7 and Δ(27), which have only one untwisted Kaehler and no untwisted complex structure modulus. Such models might be especially interesting in the context of no-scale supergravity. Finally, we briefly discuss the case of orbifolds with vanishing Euler numbers in the context of enhanced (spontaneously broken) supersymmetry.
description: 42 pages, 3 tables; v2: matches JHEP version
Nonlinear stochastic biasing of halos: Analysis of cosmological N-body simulations and perturbation theories
Creators: name: Sato, Masanori
name: Matsubara, Takahiko
Publisher: name: arXiv
Year: 2013
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: It is crucial to understand and model a behavior of galaxy biasing for future ambitious galaxy redshift surveys. Using 40 large cosmological N-body simulations for a standard LambdaCDM cosmology, we study the cross-correlation coefficient between matter and the halo density field, which is an indicator of the stochasticity of bias, over a wide redshift range 0\le z \le 3. The cross-correlation coefficient is important to extract information on the matter density field, e.g., by combining galaxy clustering and galaxy-galaxy lensing measurements. We compare the simulation results with integrated perturbation theory (iPT) proposed by one of the present authors and standard perturbation theory (SPT) combined with a phenomenological model of local bias. The cross-correlation coefficient derived from the iPT agrees with N-body simulation results down to r~15 (10) h^{-1}Mpc within 0.5 (1.0) % for all redshifts and halo masses we consider. The SPT with local bias does not explain complicated behaviors on quasilinear scales at low redshifts, while roughly reproduces the general behavior of the cross-correlation coefficient on fully nonlinear scales. The iPT is powerful to predict the cross-correlation coefficient down to quasilinear regimes with a high precision.
description: 12 pages, 6 figures. Maches version published by the Physical Review D