cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
The jet-powered optical nebula of Cygnus X-1
Creators: name: Russell, D. M.
name: Fender, R. P.
name: Gallo, E.
name: Kaiser, C. R.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present H-alpha and [O III] (5007 Angstroms) images of the nebula powered by the jet of the black hole candidate and microquasar Cygnus X-1, observed with the 2.5m Isaac Newton Telescope (INT). The ring-like structure is luminous in [O III] and there exists a thin outer shell with a high [O III] / H-alpha flux ratio. This outer shell probably originates in the collisionally excited atoms close to the front of the bow shock. Its presence indicates that the gas is shock excited as opposed to photoionised, supporting the jet-powered scenario. The shock velocity was previously constrained at 20 < v < 360 km/s; here we show that v >= 100 km/s (1 sigma confidence) based on a comparison of the observed [O III] / H-alpha ratio in the bow shock with a number of radiative shock models. From this we further constrain the time-averaged power of the jet: P_Jet = (4 - 14)*10^36 erg/s. The H-alpha flux behind the shock front is typically 4*10^-15 erg/s/cm^2/arcsec^2, and we estimate an upper limit of ~8*10^-15 erg/s/cm^2/arcsec^2 (3 sigma) to the optical (R-band) continuum flux of the nebula. The inferred age of the structure is similar to the time Cyg X-1 has been close to a bright H II region (due to the proper motion of the binary), indicating a dense local medium is required to form the shock wave. In addition, we search a > 1 square degree field of view to the south of Cyg X-1 in H-alpha (provided by the INT Photometric H-alpha Survey of the Northern Galactic Plane; IPHAS) for evidence of the counter jet interacting with the surrounding medium. Two candidate regions are identified, whose possible association with the jet could be confirmed with follow-up observations in [S II] and deeper observations in [O III] and radio.
description: Accepted for publication in MNRAS. 10 pages, 8 figures. High resolution figures can be downloaded from http://www.astro.soton.ac.uk/~davidr/mywork/Russell-CygX-1.pdf
Modelling overlap functions for one-nucleon removal: role of the effective three-nucleon force
Creators: name: Timofeyuk, N. K.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Nuclear Theory (nucl-th)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: One-nucleon overlap functions, needed for nucleon-removal reaction calculations, are solutions of an inhomogeneous equation with the source term defined by the wave functions of the initial and final nuclear states and interaction between the removed nucleon with the rest. The source term approach (STA) allows the overlaps with correct asymptotic decrease to be modelled while using nuclear many-body functions calculated in minimal model spaces. By properly choosing the removed nucleon interaction the minimum-model-space STA can reproduce reduced values of spectroscopic factors extracted from nucleon-removal reactions and predicts isospin asymmetry in the spectroscopic factor reduction. It is well-known that model space truncation leads to the appearance of higher-order induced forces, with three-nucleon force being the most important. In this paper the role of such a force on the source term calculation is studied. Applications to one-nucleon removal from double-magic nuclei show that three-nucleon force improves the description of available phenomenological overlap functions and reduces isospin asymmetry in spectroscopic factors.
description: Accepted for publication in Journal of Physics G
The rate and luminosity function of Short GRBs
Creators: name: Piran, Tsvi
name: Guetta, Dafne
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We compare the luminosity function and rate inferred from the BATSE short hard bursts (SHBs) peak flux distribution with the redshift and luminosity distributions of SHBs observed by Swift/HETE II. The Swift/HETE II SHB sample is incompatible with SHB population that follows the star formation rate. However, it is compatible with a distribution of delay times after the SFR. This would be the case if SHBs are associated with binary neutron star mergers. The implied SHB rates that we find range from \sim 8 to \sim 30h_{70}^3Gpc^{-3}yr^{-1}. This rate is a much higher than what was previously estimated and, when beaming is taken into account, it is comparable to the rate of neutron star mergers estimated from statistics of binary pulsars. If GRBs are produced in mergers the implied rate practically guarantees detection by LIGO II and possibly even by LIGO I, if we are lucky. Our analysis, which is based on observed short hard burst is limited to bursts with luminosities above 10^{49}erg/sec. Weaker bursts may exist but if so they are hardly detected by BATSE or Swift and hence their rate is very weakly constrained by current observations. Thus the rate of mergers that lead to a detection of a gravitational radiation signal might be even higher.
description: Proceedings of the conference on "Gamma Ray Bursts in the Swift Era", November 29,-December 2, Washington, DC
All-Optical and Microwave-Free Detection of Meissner Screening using Nitrogen-Vacancy Centers in Diamond
Creators: name: Paone, D.
name: Pinto, D.
name: Kim, G.
name: Feng, L.
name: Kim, M-J.
name: Stöhr, R.
name: Singha, A.
name: Kaiser, S.
name: Logvenov, G.
name: Keimer, B.
name: Wrachtrup, J.
name: Kern, K.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Microscopic studies on thin film superconductors play an important role for probing non-equilibrium phase transitions and revealing dynamics at the nanoscale. However, magnetic sensors with nanometer scale spatial and picosecond temporal resolution are essential for exploring these. Here, we present an all-optical, microwave-free method, that utilizes the negatively charged nitrogen-vacancy (NV) center in diamond as a non-invasive quantum sensor and enables the spatial detection of the Meissner state in a superconducting thin film. We place an NV implanted diamond membrane on a superconducting LSCO thin film. The strong B-field dependence of the NV photoluminescence (PL) allows us to investigate the Meissner screening in LSCO under an externally applied magnetic field in a non-resonant manner.
Search for the brightest stars in galaxies outside the Local Group
Creators: name: Tikhonov, N. A.
name: Galazutdinova, O. A.
name: Sholukhova, O. N.
name: Valcheva, A.
name: Nedialkov, P. L.
name: Merkulova, O. A.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: This paper shows a technique for searching for bright massive stars in galaxies beyond the Local Group. To search for massive stars, we used the results of stellar photometry of the Hubble Space Telescope images using the DAOPHOT and DOLPHOT packages. The results of such searches are shown on the example of the galaxies DDO68, M94 and NGC1672. In the galaxy DDO68 the LBV star changes its brightness, and in M94 massive stars can be identified by the excess in the H$α$ band. For the galaxy NGC1672, we measured the distance for the first time by the TRGB method, which made it possible to determine the luminosities of the brightest stars, likely hypergiants, in the young star formation region. So far we have performed stellar photometry of HST images of 320 northern sky galaxies located at a distance below 12Mpc. This allowed us to identify 53 galaxies with probable hypergiants. Further photometric and spectral observations of these galaxies are planned to search for massive stars.
description: Accepted for publication in Research in Astronomy and Astrophysics
Green's function approach to quantum criticality in the anisotropic Kondo-necklace model
Creators: name: Rezania, H.
name: Langari, A.
name: Thalmeier, P.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We have studied the quantum phase transition between the antiferromagnetic and spin liquid phase for the two dimensional anisotropic Kondo-necklace model. The bond operator formalism has been implemented to transform the spin Hamiltonian to a bosonic one. We have used the Green's function approach including a hard core repulsion to find the low energy excitation spectrum of the model. The bosonic excitations become gapless at the quantum critical point where the phase transition from the Kondo singlet state to long range antiferromagnetic order takes place. We have studied the effect of both inter-site (delta) and local (Delta) anisotropies on the critical point and on the critical exponent of the excitation gap in the paramagnetic phase. We have also compared our results with previous bond operator mean field calculations.
description: 14 pages and 7 EPS figures
A study of wide-band time-delayed phased-arrays with phase and frequency encoded signals for arrival-time measurement
Creators: name: Ho, Nelson
Publisher: name: University of British Columbia
Year: 2009

description: Phase-encoded signals are useful for arrival-time estimation after correlation. The bandwidth to carrier frequency ratio for the phase-encoded signals used in certain applications is very high. As the narrow-band assumption is violated, conventional phase-tuned phased-arrays suffer from dispersion and do not function properly for these applications. Time-delayed phased-arrays do not suffer from dispersion and function normally under the wide-band requirement. This thesis studies the time-delayed array and three types of modulated signals: linear Frequency Modulated (FM) signal, complementary Barker-coded Phase Modulated (PM) signal and Golomb-coded P M signal, for the purpose of arrival-time estimation. It is shown that the time-delay tuning for the linear F M signal is equivalent to linearly offsetting the initial frequency and adding a quadratic phase across the array. A new way of adjusting the element spacing for the time-delayed phased-array for the three types of signal to minimize off-tuning angle correlation is presented. Performance of the time-delayed phasedarray using the three types of signal are simulated and compared. Experiments have been performed to verify the practicality of the time-delayed phased-array.
Radio signature of a distant behind-the-limb CME on 2017 September 6
Creators: name: Melnik, V. N.
name: Rucker, H. O.
name: Brazhenko, A. I.
name: Panchenko, M.
name: Konovalenko, A. A.
name: Frantsuzenko, A. V.
name: Dorovskyy, V. V.
name: Shevchuk, M. V.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We discuss properties of a Type IV burst, which was observed on 2017 September 6, as a result of the powerful flare X 9.3. At decameter wavelengths this burst was observed by the radio telescopes STEREO A, URAN-2, and NDA at frequencies 5 - 35 MHz. This moving Type IV burst was associated with a coronal mass ejection (CME) propagating in the southwest direction with a speed of 1570 km/s. The maximum radio flux of this burst was about 300 s.f.u. and the polarization was more than 40%. In the frequency range of 8-33 MHz it continued for more than 2 hr. For STEREO A the associated CME was behind the limb, its longitudinal angle was about 160 degrees. This moving Type IV burst was observed by STEREO A at frequencies of 5-15 MHz in spite of the low sensitivity of STEREO A. This means that the radio emission directivity of a Type IV burst is rather wide. Assuming the plasma mechanism of Type IV radio emission we derived the plasma density distribution in the CME core at distances of 5.6 Rs and 9.8 Rs and its mass to be about 10^16 g . It is planned that the minimum perihelion of the Parker Solar Probe (PSP) spacecraft will be at about 9 Rs. So we discuss in what conditions PSP will be in if it crosses a similar CME core.
description: 9 pages, 6 figures, 1 table
Tentative detection of HC5NH+ in TMC-1
Creators: name: Marcelino, N.
name: Agundez, M.
name: Tercero, B.
name: Cabezas, C.
name: Bermudez, C.
name: Gallego, J. D.
name: de Vicente, P.
name: Cernicharo, J.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Using the Yebes 40m radio telescope, we report the detection of a series of seven lines harmonically related with a rotational constant B0=1295.81581 +/- 0.00026 MHz and a distortion constant D0=27.3 +/- 0.5 Hz towards the cold dense cloud TMC-1. Ab initio calculations indicate that the best possible candidates are the cations HC5NH+ and NC4NH+. From a comparison between calculated and observed rotational constants and other arguments based on proton affinities and dipole moments, we conclude that the best candidate for a carrier of the observed lines is the protonated cyanodiacetylene cation, HC5NH+. The HC5N/HC5NH+ ratio derived in TMC-1 is 240, which is very similar to the HC3N/HC3NH+ ratio. Results are discussed in the framework of a chemical model for protonated molecules in cold dense clouds.
description: Accepted for publication in A&A Letters
Four-dimensional symplectic cobordisms containing three-handles
Creators: name: Gay, David T
Publisher: name: arXiv
Year: 2006
Subjects: subject: Geometric Topology (math.GT)
subject: Symplectic Geometry (math.SG)
subject: FOS: Mathematics
subject: 53D35, 57R17, 53D20, 57M50

description: We construct four-dimensional symplectic cobordisms between contact three-manifolds generalizing an example of Eliashberg. One key feature is that any handlebody decomposition of one of these cobordisms must involve three-handles. The other key feature is that these cobordisms contain chains of symplectically embedded two-spheres of square zero. This, together with standard gauge theory, is used to show that any contact three-manifold of non-zero torsion (in the sense of Giroux) cannot be strongly symplectically fillable. John Etnyre pointed out to the author that the same argument together with compactness results for pseudo-holomorphic curves implies that any contact three-manifold of non-zero torsion satisfies the Weinstein conjecture. We also get examples of weakly symplectically fillable contact three-manifolds which are (strongly) symplectically cobordant to overtwisted contact three-manifolds, shedding new light on the structure of the set of contact three-manifolds equipped with the strong symplectic cobordism partial order.
description: This is the version published by Geometry & Topology on 28 October 2006
Effects of flexible modes and vibration damping for scaled teleoperation
Creators: name: Chen, Chia-Tung
Publisher: name: University of British Columbia
Year: 2009

description: During experiments with a dual-stage bilateral teleoperation system proposed in [1], it was observed that flexibilities in the coupling linkage of the fine manipulators and in the structure of the coarse manipulator produce vibrations that can induce instability. The effects of flexible modes on the stability robustness and performance of a bilateral motion scaling system are studied empirically. Performance is examined by comparing the environment impedance to that transmitted to the operator, while stability robustness is evaluated using the multivariable Nyquist test. Difficulties in implementing an effective active damping control with endpoint feedback are then discussed. They can be traced mostly to inaccuracies in modeling and/or sensing and actuation. The approach of passive damping is investigated in detail. The constrained layer damping technique is proposed to achieve intrinsic structural damping. The stress/strain analysis based on the Strain Energy Method first proposed by Ross, Ungar and Kerwin [2] is summarized and explained. The extension of this analysis to a hollow beam with multiple viscoelastic laminates is developed and simulation results are presented. Experiments were performed with a hollow cantilever aluminum beam with multiple damping layers, and the computed damping coefficients were compared to the measured ones.
Spatially resolved CIII]$λ$1909 emission in Haro 11
Creators: name: Micheva, Genoveva
name: Östlin, Göran
name: Melinder, Jens
name: Hayes, Matthew
name: Oey, M. S.
name: Inoue, Akio K.
name: Iwata, Ikuru
name: Adamo, Angela
name: Wisotzki, Lutz
name: Nakajima, Kimihiko
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The CIII]1909 (hereafter, C III]) line is the strongest ultraviolet emission line after Ly$α$ and is therefore of interest to high redshift studies of star-forming (SF) galaxies near the epoch of reionization. It is thought that C III] emission is strongest in galaxies with subsolar metallicity and low mass, however, spectral observations of numerous such galaxies at high and low redshift produce inconclusive or even contradictory results. We present the first ever C III ] imaging, obtained with HST/STIS for the low-redshift SF galaxy Haro 11. Cluster parameters like stellar mass, dust fraction and dust attenuation, and ionization parameter, obtained through spectral energy distribution fitting, show no correlation with the CIII] equivalent width (EW), which may be due to a combination of the limitation of the models and the age-homogeneity of the cluster population. Comparing the ratio of C III] emission line flux from individual clusters to that of H$α$, [O III], and [O II] we find that the clusters with the highest EW(C III]) can be reconciled only with Cloudy models with an extremely high C/O ratio of $\ge$ 1.4(C/O)$_\odot$ for an ionizing population of single stars, binary stars, or a mixture of binary stars and active galactic nuclei. Given the point-like nature of strong C III], the integrated total strength of EW(C III]) becomes dependent on the morphology of the galaxy, which would explain the large scatter in EW(C III]) strengths, observed in galaxies with otherwise similar SF properties, and of similarly low metallicity and stellar mass.
description: Accepted for publication in ApJ
Connection between the Loop Variable Formalism and the Old Covariant Formalsm for the Open Bosonic String
Creators: name: Sathiapalan, B.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The gauge invariant loop variable formalism and old covariant formalism for bosonic open string theory are compared in this paper. It is expected that for the free theory, after gauge fixing, the loop variable fields can be mapped to those of the old covariant formalism in bosonic string theory, level by level. This is verified explicitly for the first two massive levels. It is shown that (in the critical dimension) the fields, constraints and gauge transformations can all be mapped from one to the other. Assuming this continues at all levels one can give general arguments that the tree S-matrix (integrated correlation functions for on-shell physical fields) is the same in both formalisms and therefore they describe the same physical theory (at tree level).
description: Latex file, 24 pages
What is the time scale of random sequential adsorption?
Creators: name: Erban, Radek
name: Chapman, S. Jonathan
Publisher: name: arXiv
Year: 2006
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: Quantitative Methods (q-bio.QM)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: A simple multiscale approach to the diffusion-driven adsorption from a solution to a solid surface is presented. The model combines two important features of the adsorption process: (i) the kinetics of the chemical reaction between adsorbing molecules and the surface; and (ii) geometrical constraints on the surface made by molecules which are already adsorbed. The process (i) is modelled in a diffusion-driven context, i.e. the conditional probability of adsorbing a molecule provided that the molecule hits the surface is related to the macroscopic surface reaction rate. The geometrical constraint (ii) is modelled using random sequential adsorption (RSA), which is the sequential addition of molecules at random positions on a surface; one attempt to attach a molecule is made per one RSA simulation time step. By coupling RSA with the diffusion of molecules in the solution above the surface the RSA simulation time step is related to the real physical time. The method is illustrated on a model of chemisorption of reactive polymers to a virus surface.
description: 4 pages, submitted to Physical Review Letters
Guidelines for Life in a Pandemic:A Historical Approach
Creators: name: Fujihara, Tatsushi
Publisher: name: สมาคมญี่ปุ่นศึกษาแห่งประเทศไทย
Year: 2020
Subjects: Spain influenza
pandemic
Covid-19

description: วารสารเครือข่ายญี่ปุ่นศึกษา, 10, 2, 2-23
Effects of imperfections for Shor's factorization algorithm
Creators: name: Garcia-Mata, Ignacio
name: Frahm, Klaus M.
name: Shepelyansky, Dima L.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study effects of imperfections induced by residual couplings between qubits on the accuracy of Shor's algorithm using numerical simulations of realistic quantum computations with up to 30 qubits. The factoring of numbers up to N=943 show that the width of peaks, which frequencies allow to determine the factors, grow exponentially with the number of qubits. However, the algorithm remains operational up to a critical coupling strength $ε_c$ which drops only polynomially with $\log_2 N$. The numerical dependence of $ε_c$ on $\log_2 N$ is explained by analytical estimates that allows to obtain the scaling for functionality of Shor's algorithm on realistic quantum computers with a large number of qubits.
description: 10 pages, 10 figures, 1 table. Added references and new data. Erratum added as appendix. 1 Figure and 1 Table added. Research is available at http://www.quantware.ups-tlse.fr/
title: The Convention on Nuclear Safety for Nuclear Power Plants: Between Stability and Reform during a Quarter Century
Creators: name: Chirtes, Amelia - Paula
Publisher: name: University of Reading
Year: 2027

description: Considering the importance of protecting people and the environment against
the dangers arising from ionising radiation from nuclear installations, this research
project focuses on the Convention on Nuclear Safety applicable to nuclear power
plants, adopted in 1994 and entered into force in 1996. The research question explores
the Convention’s positioning between stability and reform, with the aid of a new model
whose application can be extended to other treaties. To support the answer to the
research question, the thesis proposes a new theoretical approach associated with the
legal analysis, which regards the Convention as a ‘formal institution’ and applies a
set of historical institutionalist concepts as an explanatory device for its evolution. The
research project studies the Convention’s formation, and its development over 25 years
since its entry into force (1996 - 2021), over a three-phase chronology. It finds that the
Treaty’s institutional architecture, designed in the aftermath of the 1986 first major
nuclear accident at Chernobyl (an exogenous shock classified at the highest severity
level), was the root cause for the Convention’s enduring path dependence. The Treaty
has remained unaffected, even when a reform could have occurred, notably in the
aftermath of the 2011 second major nuclear accident in history at Fukushima (ranked
at the highest severity level). Instead of undergoing a reform of the core Treaty (which
would have entailed important efforts in terms of time, costs, and procedures), new
developments arising from significant exogenous nuclear events and from the
Convention’s implementation monitoring have been gradually absorbed into auxiliary
legal instruments and processes (procedural arrangements and peer-review process,
declaration, standards). These are referred to in the thesis as ‘institutional
mechanisms’ supporting the Convention’s implementation. The research proposes the
new concept of the ‘institutional system of the Convention’, composed of the formal
institution and the institutional mechanisms. It finds that the Convention’s stability
was ensured through the coexistence of the path dependence of the Treaty as a formal
institution with the compensatory dynamic actualisations of the institutional
mechanisms. This formula has also ensured the institutional system’s adaptability.
Based on the Convention’s case study, the thesis proposes, as a novelty, a hybrid legal
– historical institutionalist model that can be used to study the evolution of other
international treaties in different areas, also supporting future decisions on their
development. Thereby, the thesis contributes to the international nuclear law
literature and the historical institutionalism literature.
Coherent population trapping combined with cycling transitions for quantum dot hole spins using triplet trion states
Creators: name: Carter, Samuel G.
name: Badescu, Stefan C.
name: Bracker, Allan S.
name: Yakes, Michael K.
name: Tran, Kha X.
name: Grim, Joel Q.
name: Gammon, Daniel
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Optical spin rotations and cycling transitions for measurement are normally incompatible in quantum dots, presenting a fundamental problem for quantum information applications. Here we show that for a hole spin this problem can be addressed using a trion with one hole in an excited orbital, where strong spin-orbit interaction tilts the spin. Then, a particular trion triplet forms a double $Λ$ system, even in a Faraday magnetic field, which we use to demonstrate fast hole spin initialization and coherent population trapping. The lowest trion transitions still strongly preserve spin, thus combining fast optical spin control with cycling transitions for spin readout.
description: 30 pages, 13 figures
The Molecular Hydrogen Deficit in Gamma-Ray Burst Afterglows
Creators: name: Whalen, Daniel
name: Prochaska, Jason X.
name: Heger, Alexander
name: Tumlinson, Jason
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Recent analysis of five gamma-ray burst (GRB) afterglow spectra reveal the absence of molecular hydrogen absorption lines, a surprising result in light of their large neutral hydrogen column densities and the detection of H$_2$ in similar, more local star-forming regions like 30 Doradus in the Large Magellanic Cloud (LMC). Observational evidence further indicates that the bulk of the neutral hydrogen column in these sight lines lies 100 pc beyond the progenitor and that H$_2$ was absent prior to the burst, suggesting that direct flux from the star, FUV background fields, or both suppressed its formation. We present one-dimensional radiation hydrodynamical models of GRB host galaxy environments, including self-consistent radiative transfer of both ionizing and Lyman-Werner photons, nine-species primordial chemistry with dust formation of H$_2$, and dust extinction of UV photons. We find that a single GRB progenitor is sufficient to ionize neutral hydrogen to distances of 50 - 100 pc but that a galactic Lyman-Werner background is required to dissociate the molecular hydrogen in the ambient ISM. Intensities of 0.1 - 100 times the Galactic mean are necessary to destroy H$_2$ in the cloud, depending on its density and metallicity. The minimum radii at which neutral hydrogen will be found in afterglow spectra is insensitive to the mass of the progenitor or the initial mass function (IMF) of its cluster, if present.
description: 12 pages, 7 figures, accepted for ApJ
The Complexity of Stoquastic Local Hamiltonian Problems
Creators: name: Bravyi, Sergey
name: DiVincenzo, David P.
name: Oliveira, Roberto I.
name: Terhal, Barbara M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study the complexity of the Local Hamiltonian Problem (denoted as LH-MIN) in the special case when a Hamiltonian obeys conditions of the Perron-Frobenius theorem: all off-diagonal matrix elements in the standard basis are real and non-positive. We will call such Hamiltonians, which are common in the natural world, stoquastic. An equivalent characterization of stoquastic Hamiltonians is that they have an entry-wise non-negative Gibbs density matrix for any temperature. We prove that LH-MIN for stoquastic Hamiltonians belongs to the complexity class AM -- a probabilistic version of NP with two rounds of communication between the prover and the verifier. We also show that 2-local stoquastic LH-MIN is hard for the class MA. With the additional promise of having a polynomial spectral gap, we show that stoquastic LH-MIN belongs to the class POSTBPP=BPPpath -- a generalization of BPP in which a post-selective readout is allowed. This last result also shows that any problem solved by adiabatic quantum computation using stoquastic Hamiltonians lies in PostBPP.
description: 21 pages Latex, 1 figure. v2 contains several small corrections. v3 has more small corrections
Integer point enumeration on independence polytopes and half-open hypersimplices
Creators: name: Ferroni, Luis
Publisher: name: arXiv
Year: 2020
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05B35, 52B20

description: In this paper we investigate the Ehrhart Theory of the independence matroid polytope of uniform matroids. It is proved that these polytopes have an Ehrhart polynomial with positive coefficients. To do that, we prove that indeed all half-open-hypersimplices are Ehrhart positive, and tile disjointly our polytope using them.
description: 7 pages
The relationship between driving volatility in time to collision and crash injury severity in a naturalistic driving environment
Creators: name: Wali, Behram
name: Khattak, Asad
name: Karnowski, Thomas
Publisher: name: arXiv
Year: 2020
Subjects: subject: General Economics (econ.GN)
subject: Applications (stat.AP)
subject: FOS: Economics and business
subject: FOS: Computer and information sciences

description: As a key indicator of unsafe driving, driving volatility characterizes the variations in microscopic driving decisions. This study characterizes volatility in longitudinal and lateral driving decisions and examines the links between driving volatility in time to collision and crash injury severity. By using a unique real-world naturalistic driving database from the 2nd Strategic Highway Research Program (SHRP), a test set of 671 crash events featuring around 0.2 million temporal samples of real world driving are analyzed. Based on different driving performance measures, 16 different volatility indices are created. To explore the relationships between crash-injury severity outcomes and driving volatility, the volatility indices are then linked with individual crash events including information on crash severity, drivers' pre crash maneuvers and behaviors, secondary tasks and durations, and other factors. As driving volatility prior to crash involvement can have different components, an indepth analysis is conducted using the aggregate as well as segmented (based on time to collision) real world driving data. To account for the issues of observed and unobserved heterogeneity, fixed and random parameter logit models with heterogeneity in parameter means and variances are estimated. The empirical results offer important insights regarding how driving volatility in time to collision relates to crash severity outcomes. Overall, statistically significant positive correlations are found between the aggregate (as well as segmented) volatility measures and crash severity outcomes. The findings suggest that greater driving volatility (both in longitudinal and lateral direction) in time to collision increases the likelihood of police reportable or most severe crash events... ...
Consistent de Sitter String Vacua from Kahler Stabilization and D-term uplifting
Creators: name: Parameswaran, Susha L.
name: Westphal, Alexander
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this note, we review our construction of de Sitter vacua in type IIB flux compactifications, in which moduli stabilization and D-term uplifting can be combined consistently with the supergravity constraints. Here, the closed string fluxes fix the dilaton and the complex structure moduli while perturbative quantum corrections to the Kähler potential stabilize the volume Kahler modulus in an AdS_4-vacuum. Then, magnetized D7-branes provide consistent supersymmetric D-term uplifting towards dS_4. Based on hep-th/0602253.
description: 8 pages, 1 figure, LaTeX, Contribution to the proceedings of the RTN project "Constituents, Fundamental Forces and Symmetries of the Universe" conference in Napoli, October 9-13, 2006
Characterization of the Plasmodial GTP Cyclohydrolase I enzyme as a potential antimalarial drug target using computational approaches
Creators: name: Afrah Khairallah
name: Vuyani  Moses
name: Ozlem Tastan Bishop
Publisher: name: F1000 Research Limited
Year: 2019

description: Malaria remains a global health problem. About a quarter of a billion people are infected annually, including young children, pregnant women, and non-immune travelers. Majority of the cases occur in Sub-Saharan Africa, making it a malaria-endemic region. The efficacy of current anti-malarial drugs has reduced significantly due to the parasites’ developed resistance, causing a delay in clearing it from the infected host blood system. With the problem of drug resistance on the rise, the need to develop new anti-malarial treatment strategies has become crucial. In this study, we characterize the malaria parasite GTP cyclohydrolase (GCH1) enzyme as an alternative antimalarial drug target. Sequence, motif, and phylogenetic analyses were performed to identify unique sequence features. Accurate 3D models of the five human-infective malaria parasites were calculated. Drug candidates from the South African Natural Compounds Database (SANCDB, https://sancdb.rubi.ru.ac.za/) were screened against the GCH1 enzyme. All-atom molecular dynamics (MD) simulations were carried out using the GROningen MAchine for Chemical Simulations (GROMACS) and Chemistry at HARvard Molecular Mechanics (CHARMM) MD packages to analyze the enzyme dynamical properties.
$D_{s0}(2317)$ as a tetraquark state with QCD sum rules in heavy quark limit
Creators: name: Wang, Zhi-Gang
name: Wan, Shao-Long
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In this article, we take the point of view that the charmed scalar meson $D_{s0}(2317)$ be a tetraquark state and devote to calculate its mass within the framework of the QCD sum rules approach in the heavy quark limit. The numerical values for the mass of the $D_{s0}(2317)$ are consistent with the experimental data, there must be some tetraquark component in the scalar meson $D_{s0}(2317)$. Detailed discussions about the threshold parameter and Borel parameter for the multiquark states are also presented.
description: 9 pages, 1 figure, third version
Questionnaire on Knowledge and Behavior of Snakebite in Residents(1)(1).pdf
Creators: name: He, Lanfen
name: Lv, Chuanzhu
name: Song, Xingyue
name: Hao, Wenjie
name: Wang, Juntao
name: Hu, Yanlan
name: Chen, Yu
name: Gan, Yong
name: Han, Xiaotong
name: Yan, Shijiao
Publisher: name: figshare
Year: 2024
Subjects: classificationCode: 320299
subject: Clinical sciences not elsewhere classified

description: A cross-sectional study was conducted in China from May 2022 to February 2023, using multi-stage random sampling as the primary method and snowball sampling as the secondary method to obtain the study sample. First, based on literature research and work practice, 12 provinces/municipalities/autonomous regions south of the Yangtze River Basin with incidents of severe snake bites were selected: Hubei, Hunan, Guangdong, Guangxi, Hainan, Zhejiang, Fujian, Jiangxi, Sichuan, Guizhou, Yunnan, and Chongqing. Then, a convenience sampling method was used to select three cities from each province/municipality/autonomous region, three districts/counties from each city, and three communities/villages from each district/county. A questionnaire survey was conducted among 30-50 residents from each community/village. At the same time, we used WeChat and QQ to distribute questionnaires to other unselected regions and supplemented national survey data through snowball sampling.
Parallel Spin Stripes and Their Coexistance with Superconducting Ground States at Optimal and High Doping in La$_{1.6-x}$Nd$_{0.4}$Sr$_x$CuO$_4$
Creators: name: Ma, Qianli
name: Rule, Kirrily C.
name: Cronkwright, Zachary W.
name: Dragomir, Mirela
name: Mitchell, Gabrielle
name: Smith, Evan M.
name: Chi, Songxue
name: Kolesnikov, Alexander I.
name: Stone, Matthew B.
name: Gaulin, Bruce D.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Quasi-two dimensional quantum magnetism is clearly highly correlated with superconducting ground states in cuprate-based High T$_c$ superconductivity. Three dimensional, commensurate long range magnetic order in La$_2$CuO$_4$ quickly evolves to quasi-two dimensional, incommensurate correlations on doping with mobile holes, and superconducting ground states follow for x as small as 0.05 in the La$_{2-x}$Sr$_x$/Ba$_x$CuO$_4$ family of superconductors. It has long been known that the onset of superconducting ground states in these systems is coincident with a remarkable rotation of the incommensurate spin order from "diagonal stripes" below x = 0.05, to "parallel stripes" above. However, little is known about the spin correlations at optimal and high doping levels, where the dome of superconductivity draws to an end. Here we present new elastic and inelastic neutron scattering measurements on single crystals of La$_{1.6-x}$Nd$_{0.4}$Sr$_x$CuO$_4$ with x = 0.125, 0.19, 0.24 and 0.26, and show that two dimensional, quasi-static, parallel spin stripes are observed to onset at temperatures such that the parallel spin stripe phase envelopes all superconducting ground states in this system. Parallel spin stripes stretch across 0.05 < < 0.26, with rapidly decreasing moment size and onset temperatures for x > 0.125. We also show that the low energy, parallel spin stripe fluctuations for optimally doped x = 0.19 display dynamic spectral weight which grows with decreasing temperature and saturates below its superconducting T$_c$. The elastic order parameter for x = 0.19 also shows plateau behavior coincident with the onset of superconductivity. This set of observations assert the foundational role played by two dimensional parallel spin stripe order and fluctuations in High T$_c$ cuprate superconductivity.
Fluctuations in the discrete TASEP with periodic initial configurations and the Airy_1 process
Creators: name: Borodin, Alexei
name: Ferrari, Patrik L.
name: Prähofer, Michael
Publisher: name: arXiv
Year: 2006
Subjects: subject: Mathematical Physics (math-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences
subject: 82C22, 60K35, 15A52

description: We consider the totally asymmetric simple exclusion process (TASEP) in discrete time with sequential update. The joint distribution of the positions of selected particles is expressed as a Fredholm determinant with a kernel defining a signed determinantal point process. We focus on periodic initial conditions where particles occupy dZ, d>=2. In the proper large time scaling limit, the fluctuations of particle positions are described by the Airy_1 process. Interpreted as a growth model, this confirms universality of fluctuations with flat initial conditions for a discrete set of slopes.
description: 45 pages, 7 figures, LaTeX
Research Theories and Themes on Personality Traits and Personal Data Safety
Creators: name: Manda, Vijaya Kittu
Publisher: name: Zenodo
Year: 2023
Subjects: information privacy
conspiracy theory
research theories
personality theories
privacy protection

description: Increased researcher attention is drawn to personal data privacy and security due to increased access and usage of electronic devices and the internet. Governments across the world are formulating laws and regulations to protect data privacy. Because of their personality traits, individuals play a vital role in protecting their data privacy. Much academic research went into understanding how individuals perceive and behave regarding various aspects of personal data. An examination is done using the literature review method to study recent research papers that connect to personality traits and data privacy. To understand the publication metrics on the topic, academic interest, publication trends, and keyword analysis were done. Key theories and research themes have been identified and discussed in the paper. Research papers for the literature review are taken from leading databases, and attention and importance are given to recent research papers. The theories and themes identified will help researchers and policymakers understand the theories and themes upon which most of the academic research is currently based. The direction for future research section draws attention to further research that can be done in the area.
Adaptive clock recovery and jitter control in ATM networks
Creators: name: Muhiyaddin, Ammar
Publisher: name: University of British Columbia
Year: 2009

description: Transporting continuous bit rate (CBR) or real-time periodic traffic is one of the major services that ATM-based B-ISDN technology is promising to provide. This service requires the receiver to preserve the original inter-cell spacing. However, statistical multiplexing and buffering in the ATM transport networks can introduce significant jitter in the inter-arrival period of the cell stream, thus degrading the quality, of the cell play-back at the receiver. An additional complication in plesiochronous networks is the absence of the transmitter clock frequency at the receiver. Therefore, the receiver must be capable of extracting the frequency of the transmitter clock and removing the jitter from the arriving cell stream. This thesis provides a thorough treatment of the clock recovery and jitter removal problems for CBR traffic in ATM networks, and proposes a new practical design of a receiver unit for handling multirate CBR traffic. The design proposed complies with the ATM standards. Our design employs a number of control parameters that can be varied to optimize the operation of the receiver and to provide high adaptability to rapidly changing input cell traffic. The proposed scheme is based on monitoring the fluctuation in the receiver buffer occupancy to derive a jitter free receiver clock. The hardware design has been specified and simulated extensively using VHDL (a hardware description language), and the simulation results show that our design is robust and very effective in removing cell delay jitter and restoring the original CBR stream.
MIMO Networks: the Effects of Interference
Creators: name: Chiani, Marco
name: Win, Moe Z.
name: Shin, Hyundong
Publisher: name: arXiv
Year: 2008
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: Multiple-input/multiple-output (MIMO) systems promise enormous capacity increase and are being considered as one of the key technologies for future wireless networks. However, the decrease in capacity due to the presence of interferers in MIMO networks is not well understood. In this paper, we develop an analytical framework to characterize the capacity of MIMO communication systems in the presence of multiple MIMO co-channel interferers and noise. We consider the situation in which transmitters have no information about the channel and all links undergo Rayleigh fading. We first generalize the known determinant representation of hypergeometric functions with matrix arguments to the case when the argument matrices have eigenvalues of arbitrary multiplicity. This enables the derivation of the distribution of the eigenvalues of Gaussian quadratic forms and Wishart matrices with arbitrary correlation, with application to both single user and multiuser MIMO systems. In particular, we derive the ergodic mutual information for MIMO systems in the presence of multiple MIMO interferers. Our analysis is valid for any number of interferers, each with arbitrary number of antennas having possibly unequal power levels. This framework, therefore, accommodates the study of distributed MIMO systems and accounts for different positions of the MIMO interferers.
description: Submitted to IEEE Trans. on Info. Theory
First detection of orbital motion for HD 106906 b: A wide-separation exoplanet on a Planet Nine-like orbit
Creators: name: Nguyen, Meiji M.
name: De Rosa, Robert J.
name: Kalas, Paul
Publisher: name: arXiv
Year: 2020
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: HD 106906 is a 15 Myr old short-period (49 days) spectroscopic binary that hosts a wide-separation (737 au) planetary-mass ($\sim11\,M_{\rm Jup}$) common proper motion companion, HD 106906 b. Additionally, a circumbinary debris disk is resolved at optical and near-infrared wavelengths that exhibits a significant asymmetry at wide separations that may be driven by gravitational perturbations from the planet. In this study we present the first detection of orbital motion of HD 106906 b using Hubble Space Telescope images spanning a 14 yr period. We achieve high astrometric precision by cross-registering the locations of background stars with the Gaia astrometric catalog, providing the subpixel location of HD 106906 that is either saturated or obscured by coronagraphic optical elements. We measure a statistically significant $31.8\pm7.0$ mas eastward motion of the planet between the two most constraining measurements taken in 2004 and 2017. This motion enables a measurement of the inclination between the orbit of the planet and the inner debris disk of either $36_{-14}^{+27}$ deg or $44_{-14}^{+27}$ deg, depending on the true orientation of the orbit of the planet. There is a strong negative correlation between periastron and mutual inclination; orbits with smaller periastra are more misaligned with the disk plane. With a periastron of $510_{-320}^{+480}$ au, HD 106906 b is likely detached from the planetary region within 100 au radius, showing that a Planet Nine-like architecture can be established very early in the evolution of a planetary system.
description: 38 pages, 14 figures. Published in The Astronomical Journal on December 10, 2020