cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
A longitudinal analysis of students' motivational characteristics in introductory physics courses: Gender differences
Creators: name: Marshman, Emily
name: Kalender, Zeynep Y.
name: Schunn, Christian
name: Nokes-Malach, Timothy
name: Singh, Chandralekha
Publisher: name: arXiv
Year: 2021
Subjects: subject: Physics Education (physics.ed-ph)
subject: FOS: Physical sciences

description: The lack of diversity and the under-performance of underrepresented students in STEM courses have been the focus of researchers in the last decade. In particular, many hypotheses have been put forth for the reasons for the under-representation and under-performance of women in physics. Here, we present a framework for helping all students learn in science courses that takes into account four factors: 1) characteristics of instruction and learning tools, 2) implementation of instruction and learning tools, 3) student characteristics, and 4) students' environments. While there has been much research on factor 1 (characteristics of instruction and learning tools), there has been less focus on factor 2 (students' characteristics, and in particular, motivational factors). Here, we focus on the baseline motivational characteristics of introductory physics students obtained from survey data to inform factor 2 of the framework. A longitudinal analysis of students' motivational characteristics in two-semester introductory physics courses was performed by administering pre- and post-surveys that evaluated students' self-efficacy, grit, fascination with physics, value associated with physics, intelligence mindset, and physics epistemology. Female students reported lower self-efficacy, fascination and value, and had a more "fixed" view of intelligence in the context of physics compared to male students. Grit was the only factor on which female students reported averages that were equal to or higher than male students throughout introductory physics courses. These gender differences can at least partly be attributed to the societal stereotypes and biases about who belongs in physics and can excel in it. The findings inform the framework and have implications for the development and implementation of effective pedagogies and learning tools to help all students learn.
description: published in the issue honoring first tenured female physics professor in Canada, Dr. Ursula Franklin
Partial dynamical symmetry from energy density functionals
Creators: name: Nomura, K.
name: Gavrielov, N.
name: Leviatan, A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Nuclear Theory (nucl-th)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: We show that the notion of partial dynamical symmetry is robust and founded on a microscopic many-body theory of nuclei. Based on the universal energy density functional framework, a general quantal boson Hamiltonian is derived and shown to have essentially the same spectroscopic character as that predicted by the partial SU(3) symmetry. The principal conclusion holds in two representative classes of energy density functionals: nonrelativistic and relativistic. The analysis is illustrated in application to the axially-deformed nucleus $^{168}$Er.
description: 7 pages, 3 figures, 1 table
Οι επιπτώσεις της ακτινοβολίας σε ζωντανούς οργανισμούς – Στατιστική ανάλυση βιοϊατρικών δεδομένων
Creators: name: Φανάρας, Σωτήριος Θωμά
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Ανάλυση Βιοϊατρικών Δεδομένων
Ανάλυση Βιοϊατρικών Δικτύων
Επιπτώσεις Ακτινοβολίας
Biomedical Data Analysis
Biomedical Networks Analysis
Effect of Radiation

description: Σκοπός της εργασίας είναι να παρουσιάσει την ανάλυση Βιοϊατρικών δεδομένων που σχετίζονται με την επίδραση που έχει η χαμηλής δόσης ιονίζουσα ακτινοβολία στα κύτταρα των ζωντανών οργανισμών. Αρχικά, γίνεται αναφορά στις επιπτώσεις από την έκθεση σε ιονίζουσα ακτινοβολία χαμηλής δόσης και αναφέρονται αρκετές περιπτώσεις όπου ζώντες οργανισμοί δέχτηκαν τέτοιας μορφής ακτινοβολία. Εν συνεχεία, αναφέρονται διάφορα εργαλεία και βάσεις δεδομένων που συνδέουν μεταβολές στην έκφραση γνωστών γονιδίων και πρωτεϊνών με την ανάπτυξη συγκεκριμένων ασθενειών. Τέλος, πραγματοποιήθηκε στατιστική ανάλυση δεδομένων και έγινε προσπάθεια κατασκευής μοντέλου που να εξηγεί το φαινόμενο της υπερέκφρασης και υποέκφρασης των γονιδίων ώστε να τα συσχετίσει με την εμφάνιση ορισμένων μορφών ασθενειών
description: The aim of the present thesis was the study of biomedical data related to the effect of low dose ionizing radiation on the cells of living organisms. Initially, reference is made to the effects of exposure to low dose ionizing radiation, and several cases are reported where living organisms have received such radiation. Furthermore, various tools and databases are reported that link changes in the expression of known genes and proteins with the development of specific diseases. Finally, a statistical analysis of the data was performed and a model was attempted to explain the phenomenon of overexpression and underexpression of genes in order to correlate them with the occurrence of certain forms of diseases
Multifractal analysis in non-uniformly hyperbolic interval maps
Creators: name: Ma, Guan-Zhong
name: Shen, Wen-Qiang
name: Yao, Xiao
Publisher: name: arXiv
Year: 2021
Subjects: subject: Dynamical Systems (math.DS)
subject: FOS: Mathematics
subject: 37B40, 28A80

description: In this paper, we study the Hausdorff dimension of the generalized intrinsic level set with respect to the given ergodic meausre in a class of non-uniformly hyperbolic interval maps with finitely many branches.
M-theory compactifications on hyperbolic spaces
Creators: name: Orlando, Domenico
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Negatively-curved, maximally symmetric hyperbolic spaces enjoy a number of remarkable properties that can be traced back to Riemannian geometry, group theory and algebraic geometry. In this note we recall some such properties and find $H_n$ as M-theory solutions.
description: 8 pages. Based on a talk given at the RTN Workshop 2006, Napoli
Measurement of Direct Emission in the KL->pi+pi-gamma Decay Mode
Creators: name: KTeV Collaboration
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: In this paper the KTeV collaboration reports the analysis of 112.1*10^3 candidate KL->pi+pi-gamma decays including a background of 671+/-41 events with the objective of determining the photon production mechanisms intrinsic to the decay process. These decays have been analyzed to extract the relative contributions of the CP violating bremsstrahlung process and the CP conserving M1 and CP violating E1 direct photon emission processes. The M1 direct photon emission amplitude and its associated vector form factor parameterized as |g_M1|(1+ (a_1/a_2)/(M(rho)^2-M(K)^2+2M(K)*E(gamma)) have been measured to be |g_M1|=1.198 +/- 0.035(stat) +/- 0.086(syst) and a_1/a_2 = -0.738 +/- 0.007(stat) +/- 0.018 (syst) GeV^2/c^2 respectively. An upper limit for the CP violating E1 direct emission amplitude |g_E1| < 0.21 (90% CL) has been found. The overall ratio of direct photon emission (DE) to total photon emission including the bremsstrahlung process (IB) has been determined to be DE/(DE +IB) = 0.689 +/- 0.021 for E(gamma) > 20 MeV.
description: REVTeX 3.1, 4 pages, 4 figures submitted to Physical Review Letters
Implications of new evidence for lepton-universality violation in $b\to s\ell^+\ell^-$ decays
Creators: name: Geng, Li-Sheng
name: Grinstein, Benjamín
name: Jäger, Sebastian
name: Li, Shuang-Yi
name: Camalich, Jorge Martin
name: Shi, Rui-Xiang
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Motivated by renewed evidence for new physics in $b \to s\ell\ell$ transitions in the form of LHCb's new measurements of theoretically clean lepton-universality ratios and the purely leptonic $B_s\toμ^+μ^-$ decay, we quantify the combined level of discrepancy with the Standard Model and fit values of short-distance Wilson coefficients. A combination of the clean observables $R_K$, $R_{K^*}$, and $B_s\to μμ$ alone results in a discrepancy with the Standard Model at $4.0σ$, up from $3.5σ$ in 2017. One-parameter scenarios with purely left-handed or with purely axial coupling to muons fit the data well and result in a $\sim 5 σ$ pull from the Standard Model. In a two-parameter fit of %$C_9$ and $C_{10}$, new-physics contributions with both vector and axial-vector couplings to muons the allowed region is much more restricted than in 2017, principally due to the much more precise result on $B_s \to μ^+ μ^-$, which probes the axial coupling to muons.Including angular observables data restricts the allowed region further.A by-product of our analysis is an updated average of $\text{BR}(B_s \to μ^+ μ^-) = (2.8\pm 0.3) \times 10^{-9}$.
description: In the Appendix, we update the clean fits by considering the latest measurements of the branching fraction ratios $R_{K^0_s}$ and $R_{K^{*+}}$ by the LHCb Collaboration and show that two one-parameter scenarios and a two-parameter scenario fit the data well and result in a pull from the SM crossing the 5.0$\sigma$ threshold
Parameterized Energy-Optimal Regenerative Braking Strategy for Connected and Autonomous Electrified Vehicles: A Real-Time Dynamic Programming Approach
Creators: name: Kim, Dohee
name: Eo, Jeong Soo
name: Kim, Kwang-Ki K.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optimization and Control (math.OC)
subject: Systems and Control (eess.SY)
subject: FOS: Mathematics
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: This paper presents a vehicle speed planning system called the energy-optimal deceleration planning system (EDPS), which aims to maximize energy recuperation of regenerative braking of connected and autonomous electrified vehicles. A recuperation energy-optimal speed profile is computed based on the impending deceleration requirements for turning or stopping at an intersection. This is computed to maximize the regenerative braking energy while satisfying the physical limits of an electrified powertrain. In automated driving, the powertrain of an electrified vehicle can be directly controlled by the vehicle control unit such that it follows the computed optimal speed profile. To obtain smooth optimal deceleration speed profiles, optimal deceleration commands are determined by a parameterized polynomial-based deceleration model that is obtained by regression analyses with real vehicle driving test data. The parameters are dependent on preview information such as residual time and distance as well as target speed. The key design parameter is deceleration time, which determines the deceleration speed profile to satisfy the residual time and distance constraints as well as the target speed requirement. The bounds of deceleration commands corresponding to the physical limits of the powertrain are deduced from realistic deceleration test driving. The state constraints are dynamically updated by considering the anticipated road load and the deceleration preference. For validation and comparisons of the EDPS with different preview distances, driving simulation tests with a virtual road environment and vehicle-to-infrastructure connectivity are presented. It is shown that the longer preview distance in the EDPS, the more energy-recuperation. In comparison with driver-in-the-loop simulation tests, EDPS-based autonomous driving shows improvements in energy recuperation and reduction in trip time.
Parton physics from a heavy-quark operator product expansion: Formalism and Wilson coefficients
Creators: name: Detmold, William
name: Grebe, Anthony V.
name: Kanamori, Issaku
name: Lin, C. -J. David
name: Perry, Robert J.
name: Zhao, Yong
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Parton distribution functions (PDFs) and light-cone distribution amplitudes (LCDAs) are central non-perturbative objects of interest in high-energy inelastic and elastic scattering, respectively. As a result, an ab-initio determination of these objects is highly desirable. In this paper we present theoretical details for the calculation of the PDFs and LCDAs using a heavy-quark operator product expansion method. This strategy was proposed in a previous paper [Phys. Rev. D 73, 014501 (2006)] for computing higher moments of the PDFs using lattice QCD. Its central feature is the introduction of a fictitious, valence heavy quark. In the current article, we show that the operator product expansion (OPE) of the hadronic matrix element we study can also be expressed as the convolution of a perturbative matching kernel and the corresponding light-cone distribution, which in principle can be inverted to determine the parton momentum fraction dependence. Regarding the extraction of higher moments, this work also provides the one-loop Wilson coefficients in the OPE formulas for the unpolarized PDF, helicity PDF and pseudo-scalar meson LCDAs. Although these Wilson coefficients for the PDFs can be inferred from existing results in the literature, those for the LCDAs are new.
description: 22 pages, 3 figures; Text updated to be consistent with published version
(2+1)D Exotic Newton-Hooke Symmetry, Duality and Projective Phase
Creators: name: Alvarez, Pedro D.
name: Gomis, Joaquim
name: Kamimura, Kiyoshi
name: Plyushchay, Mikhail S.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: A particle system with a (2+1)D exotic Newton-Hooke symmetry is constructed by the method of nonlinear realization. It has three essentially different phases depending on the values of the two central charges. The subcritical and supercritical phases (describing 2D isotropic ordinary and exotic oscillators) are separated by the critical phase (one-mode oscillator), and are related by a duality transformation. In the flat limit, the system transforms into a free Galilean exotic particle on the noncommutative plane. The wave equations carrying projective representations of the exotic Newton-Hooke symmetry are constructed.
description: 30 pages, 2 figures; typos corrected
Failed clinical trials on COVID-19 acute respiratory distress syndrome in hospitalized patients: common oversights and streamlining the development of clinically effective therapeutics
Creators: name: Battaglini, Denise
name: Cruz, Fernanda
name: Robba, Chiara
name: Pelosi, Paolo
name: Rocco, Patricia R.M.
Publisher: name: Taylor & Francis
Year: 2022
Subjects: subject: Medicine
subject: Genetics
subject: FOS: Biological sciences
subject: Biotechnology
subject: Information Systems not elsewhere classified
subject: Cancer
subject: Science Policy

description: The coronavirus disease 2019 (COVID-19) pandemic has put a strain on global healthcare systems. Despite admirable efforts to develop rapidly new pharmacotherapies, supportive treatments remain the standard of care. Multiple clinical trials have failed due to design issues, biased patient enrollment, small sample sizes, inadequate control groups, and lack of long-term outcomes monitoring. This narrative review depicts the current situation around failed and success COVID-19 clinical trials and recommendations in hospitalized patients with COVID-19, oversights and streamlining of clinically effective therapeutics. PubMed, EBSCO, Cochrane Library, and WHO and NIH guidelines were searched for relevant literature up to 5 August 2022. The WHO, NIH, and IDSA have issued recommendations to better clarify which drugs should be used during the different phases of the disease. Given the biases and high heterogeneity of published studies, interpretation of the current literature is difficult. Future clinical trials should be designed to standardize clinical approaches, with appropriate organization, patient selection, addition of control groups, and careful identification of disease phase to reduce heterogeneity and bias and should rely on the integration of scientific societies to promote a consensus on interpretation of the data and recommendations for optimal COVID-19 therapies.
Lagrangian 3-torus fibrations
Creators: name: Castano-Bernard, R.
name: Matessi, D.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Symplectic Geometry (math.SG)
subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 53D05,14J32

description: We give a method to construct singular Lagrangian 3-torus fibrations over certain a priori given integral affine manifolds with singularities, which we call simple. The main result of this article is the proof that the topological Calabi-Yau compactifications of M. Gross' "Topological Mirror Symmetry", can be made into symplectic compactifications. As an example, we obtain a pair of compact symplectic 6-manifolds together with Lagrangian fibrations whose underlying affine structures are dual. The symplectic manifolds obtained are homeomorphic to a smooth quintic Calabi-Yau 3-fold and its mirror.
description: 68 pages, 17 figures
Three-dimensional Coherent X-ray Diffraction Imaging via Deep Convolutional Neural Networks
Creators: name: Wu, Longlong
name: Yoo, Shinjae
name: Suzana, Ana F.
name: Assefa, Tadesse A.
name: Diao, Jiecheng
name: Harder, Ross J.
name: Cha, Wonsuk
name: Robinson, Ian K.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Image and Video Processing (eess.IV)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Applied Physics (physics.app-ph)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Physical sciences

description: As a critical component of coherent X-ray diffraction imaging (CDI), phase retrieval has been extensively applied in X-ray structural science to recover the 3D morphological information inside measured particles. Despite meeting all the oversampling requirements of Sayre and Shannon, current phase retrieval approaches still have trouble achieving a unique inversion of experimental data in the presence of noise. Here, we propose to overcome this limitation by incorporating a 3D Machine Learning (ML) model combining (optional) supervised learning with transfer learning. The trained ML model can rapidly provide an immediate result with high accuracy which could benefit real-time experiments, and the predicted result can be further refined with transfer learning. More significantly, the proposed ML model can be used without any prior training to learn the missing phases of an image based on minimization of an appropriate 'loss function' alone. We demonstrate significantly improved performance with experimental Bragg CDI data over traditional iterative phase retrieval algorithms.
Power spectrum of HI intensity fluctuations in DDO 210
Creators: name: Begum, Ayesha
name: Chengalur, Jayaram N.
name: Bharadwaj, Somnath
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We measure the power spectrum of HI intensity fluctuations in the extremely faint (M_B ~ -10.9) dwarf galaxy DDO 210 using a visibility based estimator that is well suited in very low signal to noise ratio regimes. DDO 210's HI power spectrum is well fit by a power law $P_HI(U)= A U^α$ with $α=-2.75 \pm0.45$ over the length-scales 80 pc to 500 pc. We also find that the power spectrum does not change with an increase in the velocity channel width, indicating that the measured fluctuations correspond mainly to density fluctuations. However, Kolmogorov turbulence (with a velocity structure function spectral slope of 2/3) cannot be ruled out from the present observations. The value of the slope $α$ is similar to that obtained in the Milkyway. In contrast to the Milkyway, DDO 210 has three orders of magnitude less HI, no spiral arms, and also no measurable ongoing star formation. The fact that the power spectrum slope is nonetheless similar in these two galaxies (and also similar to the values measured for the LMC and SMC) suggests that there is some universal, star formation independent, phenomenon responsible for producing fine scale structure in the gas.
description: 5 Pages, 3 Figures. Accepted for publication in MNRAS Letters
Variational equations on mixed Riemannian-Lorentzian metrics
Creators: name: Otway, Thomas H.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mathematical Physics (math-ph)
subject: Analysis of PDEs (math.AP)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 35M10, 53A10, 83C80

description: A class of elliptic-hyperbolic equations is placed in the context of a geometric variational theory, in which the change of type is viewed as a change in the character of an underlying metric. A fundamental example of a metric which changes in this way is the extended projective disc, which is Riemannian at ordinary points, Lorentzian at ideal points, and singular on the absolute. Harmonic fields on such a metric can be interpreted as the hodograph image of extremal surfaces in Minkowski 3-space. This suggests an approach to generalized Plateau problems in 3-dimensional space-time via Hodge theory on the extended projective disc. Analogous variational problems arise on Riemannian-Lorentzian flow metrics in fiber bundles (twisted nonlinear Hodge equations), and on certain singular Riemannian-Lorentzian manifolds which occur in relativity and quantum cosmology. The examples surveyed come with natural gauge theories and Hodge dualities. This paper is mainly a review, but some technical extensions are proven.
description: 28 pages
Detailed Study of the Ursa Major Supercluster of Galaxies Using the 2MASS and SDSS Catalogs
Creators: name: Kopylova, Flera
name: Kopylov, Alexander
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We study the infrared (K_s band) properties of clusters of galaxies in the Ursa Major supercluster using data from 2MASS (Two-Micron All-Sky Survey) and SDSS (Sloan Digital Sky Survey). We identified three large filaments with mean redshifts of z = 0.051, 0.060, and 0.071. All clusters of the supercluster are located in these filaments. We determined the total K_s-band luminosities and masses for 11 clusters of galaxies within comparable physical regions (within a radius R_200 close to the virial radius) using a homogeneous method. We constructed a combined luminosity function for the supercluster in this region, which can be described by the Schechter function with the following parameters: M*_K = -24^m.50 and α= -0.98. The infrared luminosities of the clusters of galaxies correlate with their masses; the M/L_K ratios of the systems increase with their masses (luminosities), with most of the Ursa Major clusters of galaxies (particularly the richer ones) closely following the relations derived previously for a large sample of clusters and groups of galaxies. The total mass-to-infrared-luminosity ratio is 52 M_{\odot}/L_{\odot} for six Abell clusters and 49 M_{\odot}/L_{\odot} for all of the clusters, except Anon2.
description: 16 pages, 5 figures
Identifying atomically thin crystals with diffusively reflected light
Creators: name: Domaretskiy, D.
name: Ubrig, N.
name: Gutiérrez-Lezama, I.
name: Tran, M. K.
name: Morpurgo, A. F.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: The field of two-dimensional materials has been developing at an impressive pace, with atomically thin crystals of an increasing number of different compounds that have become available, together with techniques enabling their assembly into functional heterostructures. The strategy to detect these atomically thin crystals has however remained unchanged since the discovery of graphene. Such an absence of evolution is starting to pose problems because for many of the 2D materials of current interest the optical contrast provided by the commonly used detection procedure is insufficient to identify the presence of individual monolayers or to determine unambiguously the thickness of atomically thin multilayers. Here we explore an alternative detection strategy, in which the enhancement of optical contrast originates from the use of optically inhomogeneous substrates, leading to diffusively reflected light. Owing to its peculiar polarization properties and to its angular distribution, diffusively reflected light allows a strong contrast enhancement to be achieved through the implementation of suitable illumination-detection schemes. We validate this conclusion by carrying out a detailed quantitative analysis of optical contrast, which fully reproduces our experimental observations on over 60 WSe$_2$ mono-, bi-, and trilayers. We further validate the proposed strategy by extending our analysis to atomically thin phosphorene, InSe, and graphene crystals. Our conclusion is that the use of diffusively reflected light to detect and identify atomically thin layers is an interesting alternative to the common detection scheme based on Fabry-Perot interference, because it enables atomically thin layers to be detected on substrates others than the commonly used Si/SiO$_2$, and it may offer higher sensitivity depending on the specific 2D material considered.
Discovery of hard X-ray delays in the X-ray emission of the Seyfert 1 galaxy Mrk~110: possible evidence for Comptonization
Creators: name: Dasgupta, Surajit
name: Rao, A. R.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report the discovery of hard X-ray delays in the X-ray emission of the Seyfert 1 galaxy Mrk 110, based on a long XMM-Newton observation. Cross correlation between the X-ray light curves of different energy bands reveals an energy dependent delay ranging from a few minutes to an hour. We find that the energy spectrum can be modeled by Comptonization of disk blackbody photons. The energy dependent delay can be modeled as due to the effect of Comptonization in a hot plasma confined within 10 Schwarzschild radius of the black hole. We discuss our results in the context of inverse Comptonization of the soft photons by highly energetic plasma.
description: 4 pages, 4 figures, To appear in Astrophysical Journal Letter
Correlations between $γ$-ray luminosity and magnetization of the jet as well as relativistic electron injection power:cases for Mrk 421, 3C 454.3 and 3C 279
Creators: name: Hu, Wen
name: Yan, Da-hai
name: Hu, Qiang-lin
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: By fitting high-quality and simultaneous multi-wavelength (MWL) spectral energy distributions (SEDs) at multiple epochs with a one-zone leptonic jet model, we study jet properties of the three famous blazars Mrk 421, 3C 454.3 and 3C 279. In the jet model, the emitting electron energy distributions (EEDs) are calculated by solving the kinetic equation of electron injection, escape, adiabatic and radiative energy losses. To explore multi-dimensional parameter space systematically, we employ a Markov chain Monte Carlo (MCMC) fitting technique. The properties of emission regions we derived here are consistent with those in previous studies, e.g., the particle-dominated and low-magnetization jet. The new finding is that there is a tight correlation between $γ$-ray luminosity and electron injection power and an anti-correlation between $γ$-ray luminosity and jet magnetization parameter. The results suggest that same energy-dissipative mechanism (like a shock) could be operating in the jets of different types of blazars, and the origin of $γ$-ray flares is associated with the particle acceleration process.
description: 17 pages, 38 figures, 2 tables; Accepted for publication in MNRAS
Two new prenylated coumarins from roots of Zanthoxylum nitidum
Creators: name: Niu, Sheng-Li
name: Lv, Tian-Meng
name: Tong, Zhi-Fan
name: Li, Xin-Yu
name: Xue, Jing-Jing
name: Yuan, Jing
name: Hu, Ping
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Biochemistry
subject: Cell Biology
subject: Pharmacology
subject: Environmental Sciences not elsewhere classified
subject: Chemical Sciences not elsewhere classified
subject: Biological Sciences not elsewhere classified
subject: Cancer
subject: Infectious Diseases
subject: FOS: Health sciences

description: Two new prenylated coumarins, 3'-hydroxytoddanone (1), and isotoddalolactone (2), along with four known analogues (3–6) were isolated from the roots of Zanthoxylum nitidum. Their chemical structures were elucidated based on extensive spectroscopic interpretation and HR-ESI-MS analysis. The absolute configuration of compound 2 was determined by comparing experimental ECD spectrum with that calculated by the time-dependent density functional theory (TDDFT) method. Compounds 4–6 were isolated from the Zanthoxylum genus for the first time. The two new compounds were tested for antiproliferative activities in vitro on the HL-60, K562 and THP-1 cell lines. Compounds 1 and 2 exhibited moderate cell growth inhibitory activities in vitro against human leukemic HL-60 cell lines, with IC50 values of 32.64 and 33.15 µM, respectively.
Does there arise a significant enhancement of the dynamical quark mass in external magnetic field?
Creators: name: Klimenko, K. G.
name: Zhukovsky, V. Ch.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Recently, it was found in QED that the generation of a dynamical electron mass in a strong magnetic field is significantly enhanced by the perturbative electron mass. In the present paper, the related question of a possible enhancement of the dynamical quark mass in an external magnetic field and with a bare mass term is investigated in the Nambu--Jona-Lasinio model.
description: 4 pages; Revtex4; new references added; version accepted for publication in Phys. Lett. B
Two c's in a pod: Cosmology independent measurement of the Type Ia supernova colour-luminosity relation with a sibling pair
Creators: name: Biswas, Rahul
name: Goobar, Ariel
name: Dhawan, Suhail
name: Schulze, Steve
name: Johansson, Joel
name: Bellm, Eric C.
name: Dekany, Richard
name: Drake, Andrew J.
name: Duev, Dmitry A.
name: Fremling, Christoffer
name: Graham, Matthew
name: Kim, Young-Lo
name: Kool, Erik C.
name: Kulkarni, Shrinivas R.
name: Mahabal, Ashish A.
name: Perley, Daniel
name: Rigault, Mickael
name: Rusholme, Ben
name: Sollerman, Jesper
name: Shupe, David L.
name: Smith, Matthew
name: Walters, Richard S.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Using Zwicky Transient Facility (ZTF) observations, we identify a pair of "sibling" Type Ia supernovae (SNe Ia), i.e., hosted by the same galaxy at z = 0.0541. They exploded within 200 days from each other at a separation of $0.6^{"} $ corresponding to a projected distance of only 0.6 kpc. Performing SALT2 light curve fits to the gri ZTF photometry, we show that for these equally distant "standardizable candles", there is a difference of 2 magnitudes in their rest frame B-band peaks, and the fainter SN has a significantly red SALT2 colour $c = 0.57 \pm$ 0.04, while the stretch values $x_1$ of the two SNe are similar, suggesting that the fainter SN is attenuated by dust in the interstellar medium of the host galaxy. We use these measurements to infer the SALT2 colour standardization parameter, $β$ = 3.5 $\pm$ 0.3, independent of the underlying cosmology and Malmquist bias. Assuming the colour excess is entirely due to dust, the result differs by $2σ$ from the average Milky-Way total-to-selective extinction ratio, but is in good agreement with the colour-brightness corrections empirically derived from the most recent SN Ia Hubble-Lemaitre diagram fits. Thus we suggest that SN "siblings", which will increasingly be discovered in the coming years, can be used to probe the validity of the colour and lightcurve shape corrections using in SN Ia cosmology while avoiding important systematic effects in their inference from global multi-parameter fits to inhomogeneous data-sets, and also help constrain the role of interstellar dust in SN Ia cosmology.
description: Replaced with version accepted in MNRAS
Study of rotational splittings in $δ$~Scuti stars using pattern finding techniques
Creators: name: Ramón-Ballesta, A.
name: Hernández, A. García
name: Suárez, J. C.
name: Rodón, J. R.
name: Pascual-Granado, J.
name: Garrido, R.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Detecting and understanding rotation in stellar interiors is nowadays one of the unsolved problems in stellar physics. Asteroseismology has been able to provide insights on rotation for the Sun, solar-like stars, and compact objects like white dwarfs. However, this is still very difficult for intermediate-mass stars. These stars are moderate-to-rapid rotators. Rotation splits and shifts the oscillation modes, which makes the oscillation spectrum more complex and harder to interpret. Here we study the oscillation patterns of a sample of benchmark $δ$~Sct stars belonging to eclipsing binary systems with the objective to find the frequency spacing related to the rotational splitting ($δr$). For this task, we combine three techniques: the Fourier transform, the autocorrelation function, and the histogram of frequency differences. The last two showed a similar behaviour. For most of the stars, it was necessary to determine the large separation ($Δν$) prior to spot $δr$. This is the first time we may clearly state that one of the periodicities present in the p~modes oscillation spectra of $δ$~Sct stars corresponds to the rotational splitting. This is true independently of the stellar rotation rate. These promising results pave the way to find a robust methodology to determine rotational splittings from the oscillation spectra of $δ$~Sct stars and, thus, understanding the rotational profile of intermediate-mass pulsating stars.
description: Accepted for publication in Monthly Notices of the Royal Astronomical Society
A synoptic comparison of the MHD and the OPAL equations of state
Creators: name: Trampedach, R.
name: Dappen, W.
name: Baturin, V. A.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: A detailed comparison is carried out between two popular equations of state (EOS), the Mihalas-Hummer-Dappen (MHD) and the OPAL equations of state, which have found widespread use in solar and stellar modeling during the past two decades. They are parts of two independent efforts to recalculate stellar opacities; the international Opacity Project (OP) and the Livermore-based OPAL project. We examine the difference between the two equations of state in a broad sense, over the whole applicable rho-T range, and for three different chemical mixtures. Such a global comparison highlights both their differences and their similarities. We find that omitting a questionable hard-sphere correction, tau, to the Coulomb interaction in the MHD formulation, greatly improves the agreement between the MHD and OPAL EOS. We also find signs of differences that could stem from quantum effects not yet included in the MHD EOS, and differences in the ionization zones that are probably caused by differences in the mechanisms for pressure ionization. Our analysis do not only give a clearer perception of the limitations of each equation of state for astrophysical applications, but also serve as guidance for future work on the physical issues behind the differences. The outcome should be an improvement of both equations of state.
description: 33 pages, 26 figures. Corrected discussion of Basu & Antia, 2004, ApJ, 606, L85-L88
The effects of a silvicultural sludge application on small mammal populations and the potential of Giardia contamination in a forest ecosystem
Creators: name: Cheng, Chris
Publisher: name: University of British Columbia
Year: 2008

description: The effects of a silvicultural sludge application on resident small mammal populations were assessed by monitoring their demographic responses before and after sewage sludge treatment. Potential contamination of the forest ecosystem by Giardia duodenalis, a parasitic protozoan, was also investigated. Populations of the deer mouse (Peromyscus maniculatus), Oregon vole (Microtus oregoni), Townsend chipmunk (Eutamias townsendii), shrews (Sorex spp.), and a few species caught occasionally, were sampled in control and treatment study sites from May 1990 to October 1991. Sludge application occurred in November 1990. There were no detectable differences in the abundances of deer mice, Oregon voles, and chipmunks on treatment areas relative to controls after sludge application. This was also the case for recruitment, survival, mean body weight, weight at sexual maturity, sex ratio, species diversity and spatial distribution. There was, however, a significant increase in the growth rate of juvenile deer mice on treatment sites after sludge application. This was also the only effect on small mammal population dynamics observed from the sludge treatment. The prevalence of Giardia spp. cysts in small mammal fecal samples on study sites did not differ between pre-sludge and post-sludge periods. My laboratory study using wild deer mice concluded that this species was capable of acting as a host to some strains of human Giardia under specific laboratory conditions. Because of the deer mouse's apparent ability to adapt well to this environmental change, as illustrated by the lack of effect on its survival and reproduction attributes, and this species' potential ability to host human Giardia, additional research and consideration are warranted prior to the implementation of large scale silvicultural sludge applications.
Καθ’ έξιν αποβολές και νοσήματα
Creators: name: Μαυρουδή, Ευαγγελία Νικολάου
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Καθ’ έξιν αποβολές
Πρόληψη
Βιολογικοί Δείκτες
Recurrent pregnancy loss
Prevention
Biological indicators

description: Οι καθ’ έξιν αποβολές και γενικότερα οι αποβολές, είναι ένα σημαντικό πρόβλημα της σύγχρονης εποχής που επηρεάζει ένα μεγάλο ποσοστό των γυναικών. Σκοπός της εργασίας αυτής είναι η ανασκόπηση των παραγόντων που οδηγούν σε καθ’ έξιν αποβολές. Καθ’ έξιν αποβολή ορίζεται η απώλεια τριών ή περισσότερων διαδοχικών κυήσεων. Αποτελούν μια ετερογενή κατάσταση που έχει πολλά πιθανά αίτια, ενώ πολύ παράγοντες μπορεί να συμβάλλουν στην εμφάνισή τους. Μερικοί από αυτούς τους παράγοντες μπορεί να είναι γενετικοί, ανατομικοί και ενδοκρινολογικοί , παρ’ όλα αυτά σε πολλές περιπτώσεις οι αιτίες παραμένουν άγνωστες. Οι περιπτώσεις αυτές είναι εξαιρετικά επίπονες για το ζευγάρι, αφού όσο παραμένει ανεξήγητη η αιτία δεν μπορεί να αντιμετωπιστεί. Αρχικά αναλύονται τα είδη και οι περιπτώσεις των καθ’ έξιν αποβολών και ύστερα παρατίθενται συγκεντρωτικά οι μέθοδοι πρόληψης και θεραπείας. Τέλος, αναφέρονται ειδικοί βιολογικοί δείκτες οι οποίοι θα πρέπει να λαμβάνονται υπόψιν και να εξετάζονται, έτσι ώστε τα ζευγάρια με εμφάνιση επαναλαμβανόμενων αποβολών να μπαίνουν στην διαδικασία ελέγχου και εξέτασης. Εκτός από τους στόχους και τις προτάσεις των ερευνών που αναφέρονται σε αυτή την εργασία, γίνεται λόγος και για περαιτέρω μελλοντικές μελέτες και διερευνήσεις
description: Recurrent pregnancy loss (RPL) and other types of miscarriages are surprisingly common nowadays. The aim of this study is to analyze the factors that cause recurrent miscarriages. RPL is three or more consecutive pregnancy losses. They constitute a heterogenous case that includes many possible causes, while there are multiple factors that can cause them. These factors can be genetic, anatomical and endocrine, but still in many cases the causes of RPL remain unknown. This fact is extremely painful for the couple, because as long as the element remains unexplained it cannot be treated. First of all, the types and the miscarriage cases are analyzed. Methods of prevention, treatment and testing are also mentioned. At the end of the thesis, there is also an analysis of specific biological markers, which should be taken into consideration and examined. It is extremely important for the couples with RPL to enter screening and testing process. Besides this research objectives and suggestions stated in this thesis there are more directions for further analysis and future investigations.
description: Σε συνεργασία με το Τμήμα Ιατρικής της Σχολής Επιστημών Υγείας του Δημοκρίτειου Πανεπιστημίου Θράκης (ΔΠΘ)και το Τμήμα Πολιτικών Μηχανικών ΤΕ της Σχολής Τεχνολογικών Εφαρμογών του Αλεξάνδρειου ΤΕΙ Θεσσαλονίκης (ΑΤΕΙΘ)
Convex cones and SAGBI bases of permutation invariants
Creators: name: Thiéry, Nicolas M.
name: Thomassé, Stéphan
Publisher: name: arXiv
Year: 2006
Subjects: subject: Commutative Algebra (math.AC)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 13A50 (Primary) 13P10 (Secondary)

description: Let G be a permutation group acting on {1,...,n}, and < be any admissible term order on the polynomial ring K[x_1,...,x_n]. We prove that the invariant ring K[x_1,...,x_n]^G of G has a finite SAGBI basis if, and only if, G is generated by reflections.
description: 4 pages
Modified Afshar Experiment: Calculations
Creators: name: Flores, Eduardo V.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The Afshar experiment is a relatively simple two-slit experiment with results that appear to show a discrepancy with the predictions of Bohr's Principle of Complementarity. We report on the results of a calculation using a simpler but equivalent set-up called the modified Afshar experiment. Numerical results are in agreement with the experimental results performed on the Afshar experiment set-up. Calculations show that the level of which-way information and visibility in the Afshar experiement is higher than originally estimated.
description: Typos have been corrected. Two sections added: visibility and which-way information. Conclusions section revised. Reference [4] has been changed
Simultaneous Measurement of Non-Commuting Observables
Creators: name: Aquino, G.
name: Mehmani, B.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: It is shown that the full unknown state of a spin-1/2 system, S, which, within Born's statistical interpretation, is meant as the state of an ensamble of identically prepared systems, can be determined with a simultaneous measurement with the help of an "assistant" system A whose initial state is known. The idea is to let S and A interact with each other in a known way during a proper interaction time, to measure simultaneously two observables, one of S and one of A and their correlation. One thus determines the three unknown components of the polarization vector of S by means of repeated experiments using a unique setting. In this way one can measure simultaneously all the non-commutative observables of S, which might seem prohibited in quantum mechanics.
description: 10 pages, 1 figure; Proceedings of the Workshop "Beyond the Quantum" World Scientific (2007)
Different faces of the phantom
Creators: name: Bronnikov, K. A.
name: Fabris, J. C.
name: Gonçalves, S. V. B.
Publisher: name: arXiv
Year: 2006
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The SNe type Ia data admit that the Universe today may be dominated by some exotic matter with negative pressure violating all energy conditions. Such exotic matter is called {\it phantom matter} due to the anomalies connected with violation of the energy conditions. If a phantom matter dominates the matter content of the universe, it can develop a singularity in a finite future proper time. Here we show that, under certain conditions, the evolution of perturbations of this matter may lead to avoidance of this future singularity (the Big Rip). At the same time, we show that local concentrations of a phantom field may form, among other regular configurations, black holes with asymptotically flat static regions, separated by an event horizon from an expanding, singularity-free, asymptotically de Sitter universe.
description: 6 pages, presented at IRGAC 2006, Barcelona, 11-15 July 2006
Πεδινές χορτολιβαδικές εκτάσεις στους δασικούς χάρτες και ο προσδιορισμός τους με την χρήση γεωγραφικών συστημάτων πληροφοριών (GIS)
Creators: name: Ντόγας Γεώργιος Κωνσταντίνου
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Πεδινά χορτολίβαδα
Δασικός Χάρτης
Κτηματολόγιο
Κλίση
Υψόμετρο
Lowland grassland
Forest map
Cadastre
Slope
Altitude

description: Είναι γεγονός ότι το δαιδαλώδες και πολύπλοκο νομοθετικό πλαίσιο που διέπει σήμερα τις χορτολιβαδικές εκτάσεις, εμποδίζει την ορθή επίλυση ιδιοκτησιακών ζητημάτων τόσο στο πλαίσιο των Δασικών Χαρτών όσο και στο Εθνικό Κτηματολόγιο. Ιδιαίτερα ένα ζήτημα που έχει προκύψει με την ανάρτηση των Δασικών Χαρτών αφορά τον χαρακτηρισμό των χορτολιβαδικών εκτάσεων ως δασικές. Επιπρόσθετα, με την έκδοση του Π.Δ. 32/2016 τα κριτήρια χαρακτηρισμού μιας χορτολιβαδικής έκτασης σε πεδινή, και μη πεδινή, εξειδικεύονται με βάση το υψόμετρο, τις κλίσεις των εδαφών και τη σύνθεση της βλάστησης. Όλα τα παραπάνω κριτήρια ωστόσο, αφήνουν περιθώρια ερμηνείας τέτοια που να δημιουργούν προβλήματα, όπως αυτά που παρατηρήθηκαν με την ανάρτηση των Δασικών Χαρτών σε πολλά νησιά του Αιγαίου. Λαμβάνοντας όλα τα παραπάνω υπόψη, η παρούσα εργασία έχει ως σκοπό, μέσω της χρήσης του ArcGIS, να αναλύσει τη μεθοδολογία ταυτοποίησης και ελέγχου των πολύγωνων που έχουν χαρακτηρισθεί ως πεδινά χορτολίβαδα στο Δασικό Χάρτη, ούτως ώστε να διαπιστωθεί εάν όντως αυτά πληρούν τις προϋποθέσεις κλίσης και υψομέτρου των δασικών προδιαγραφών
description: The fact that the intricate and complex legislative framework currently governing the grassland, prevent the proper settlement of property issues, both within the forest maps and the National Cadastre. Particularly an issue that has arisen with the posting of Forest Maps concerns the classification of grassland as forest. In addition, with the publication of the PD 32/2016 the criteria for designating a lowland and non-lowland area are specified by altitude, soil slopes and vegetation composition. All of the above criteria, however, leave room for interpretation such as to create problems such as those observed with the posting of Forest Maps in many Aegean islands. Taking all this into account, this paper aims, through the use of ArcGIS, analyze the polygon identification and control methodology are classified as lowland grasslands in Forest Charter, he to see if indeed they meet the slope conditions and altitude of forest specifications