cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Quantitative Amenability for Actions of Finitely Generated Groups
Creators: name: Xia, Zihan
Publisher: name: University of Illinois at Chicago
Year: 2024

description: We generalize the notion of isoperimetric profiles of finitely generated groups to their actions by measuring the boundary of finite subgraphings of the orbit graphing. The decay of such isoperimetric profile is asymptotically invariant if the Radon-Nikodym derivatives is L∞ bounded, and invariant up to a polynomial bound in most cases. We prove that like the classical isoperimetric profiles for groups, decay of the isoperimetric profile for an essentially-free action is equivalent to amenability of the action in the sense of Zimmer. For measure-preserving actions, we relate the isoperimetric profiles of the actions and the group. We proved that these two isoperimetric profiles are asymptotic same if the group
has a sequence of Følner multi-tilings. Moreover, we talk about example of the isoperimetric profile for the actions of free groups on its Poisson boundary in the case of simple random walks, and gives its lower boundary of the decay.
Dark states in the magnetotransport through triple quantum dots
Creators: name: Emary, Clive
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We consider the transport through a system of three coupled quantum dots in a perpendicular magnetic field. At zero field, destructive interference can trap an electron in a dark state -- a coherent superposition of dot states that completely blocks current flow. The magnetic field can disrupt this interference giving rise to oscillations in the current and its higher-order statistics as the field is increased. These oscillations have a period of either the flux-quantum or half the flux-quantum, depending on the dot geometry. We give results for the stationary current and for the shotnoise and skewness at zero and finite frequency.
description: 7 pages, 7 figures
Mid-IR cosmological spectrophotometric surveys from space: Measuring AGN and star formation at the Cosmic Noon with a SPICA-like mission
Creators: name: Spinoglio, Luigi
name: Mordini, Sabrina
name: Fernandez-Ontiveros, Juan Antonio
name: Alonso-Herrero, Almudena
name: Armus, Lee
name: Bisigello, Laura
name: Calura, Francesco
name: Carrera, Francisco J.
name: Cooray, Asantha
name: Dannerbauer, Helmut
name: Decarli, Roberto
name: Egami, Eiichi
name: Elbaz, David
name: Franceschini, Alberto
name: Alfonso, Eduardo Gonzalez
name: Graziani, Luca
name: Gruppioni, Carlotta
name: Hatziminaoglou, Evanthia
name: Kaneda, Hidehiro
name: Kohno, Kotaro
name: Labiano, Alvaro
name: Magdis, Georgios
name: Malkan, Matthew A.
name: Matsuhara, Hideo
name: Nagao, Tohru
name: Naylor, David
name: Pereira-Santaella, Miguel
name: Pozzi, Francesca
name: Rodighiero, Giulia
name: Roelfsema, Peter
name: Serjeant, Stephen
name: Vignali, Cristian
name: Wang, Lingyu
name: Yamada, Toru
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We use the SPace Infrared telescope for Cosmology and Astrophysics (SPICA) project as a template to demonstrate how deep spectrophotometric surveys covering large cosmological volumes over extended fields (1-15 square degrees) with a mid-IR imaging spectrometer (17-36 micron) in conjunction with deep 70 micron photometry with a far-IR camera, at wavelengths which are not affected by dust extinction can answer the most crucial questions in current galaxy evolution studies. A SPICA-like mission will be able for the first time to provide an unobscured three dimensional (3-D, i.e. x, y and redshift z) view of galaxy evolution back to an age of the Universe of less than ~2 Gyrs, in the mid-IR rest-frame. This survey strategy will produce a full census of the Star formation Rate (SFR) in the Universe, using Polycyclic Aromatic Hydrocarbons (PAH) bands and fine-structure ionic lines, reaching the characteristic knee of the galaxy luminosity function, where the bulk of the population is distributed, at any redshift up to z ~3.5. Deep follow-up pointed spectroscopic observations with grating spectrometers { onboard the satellite}, across the full IR spectral range (17-210 micron), would simultaneously measure Black Hole Accretion Rate (BHAR), from high-ionization fine-structure lines, and SFR, from PAH and low- to mid-ionization lines in thousands of galaxies from solar to low metallicities, down to the knee of their luminosity functions. The analysis of the resulting atlas of IR spectra will reveal the physical processes at play in evolving galaxies across cosmic time, especially its heavily dust-embedded phase during the activity peak at the cosmic noon (z ~1-3), through IR emission lines and features that are insensitive to the dust obscuration.
description: Paper accepted for publication on PASA on 5th March 2021, as part of the SPICA Special Issue
Approximations to Euler's constant
Creators: name: Pilehrood, Kh. Hessami
name: Pilehrood, T. Hessami
Publisher: name: arXiv
Year: 2007
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11Y60, 11Y35, 41A25

description: We study a problem of finding good approximations to Euler's constant $γ=\lim_{n\to\infty}S_n,$ where $S_n=\sum_{k=1}^n\frac{1}{n}-\log(n+1),$ by linear forms in logarithms and harmonic numbers. In 1995, C. Elsner showed that slow convergence of the sequence $S_n$ can be significantly improved if $S_n$ is replaced by linear combinations of $S_n$ with integer coefficients. In this paper, considering more general linear transformations of the sequence $S_n$ we establish new accelerating convergence formulae for $γ.$ Our estimates sharpen and generalize recent Elsner's, Rivoal's and author's results.
description: 11 pages
An Accreting Black Hole in the Nuclear Star Cluster of the Bulgeless Galaxy NGC 1042
Creators: name: Shields, Joseph C.
name: Walcher, C. Jakob
name: Boeker, Torsten
name: Ho, Luis C.
name: Rix, Hans-Walter
name: van der Marel, Roeland P.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present spectroscopic evidence for a low-luminosity, low-excitation active galactic nucleus (AGN) in NGC 1042, powered by an intermediate-mass black hole. These findings are significant in that the AGN is coincident with a compact star cluster known to reside in the nucleus, thus providing an example where the two types of central mass concentration coexist. The existence of a central black hole is additionally remarkable in that NGC 1042 lacks a stellar bulge. Objects such as NGC 1042 may have an important role in testing theories for the genesis of massive black holes in galaxy nuclei, and the extent to which they are in symbiosis with the larger stellar host.
description: 15 pages, 6 figures, accepted for publication in ApJ
Dynamics and self-similarity in min-driven clustering
Creators: name: Menon, Govind
name: Niethammer, Barbara
name: Pego, Robert L.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: FOS: Physical sciences

description: We study a mean-field model for a clustering process that may be described informally as follows. At each step a random integer $k$ is chosen with probability $p_k$, and the smallest cluster merges with $k$ randomly chosen clusters. We prove that the model determines a continuous dynamical system on the space of probability measures supported in $(0,\infty)$, and we establish necessary and sufficient conditions for approach to self-similar form. We also characterize eternal solutions for this model via a Levy-Khintchine formula. The analysis is based on an explicit solution formula discovered by Gallay and Mielke, extended using a careful choice of time scale.
Andreev reflection and Josephson effect in the $α$-T3 lattice
Creators: name: Zhou, Xingfei
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We investigate the Andreev reflection and Josephson effect in the $α$-T3 lattice which falls between graphene ($α= 0$) and the dice lattice ($α= 1$) by adjusting the parameter $α$. In the regime of specular Andreev reflection, when the incident energy of electron is small, the probability of Andreev reflection decreases as the parameter $α$ increases. On the contrary, when the incident energy is large, the probability of Andreev reflection increases as the parameter $α$ increases. Interestingly, when the incident energy approaches the superconducting energy-gap function, the Andreev reflection with approximate all-angle perfect transmission happens in the case of $α= 1$. In the regime of Andreev retro-reflection, when the parameter $α$ increases, the probability of Andreev reflection increases regardless of the value of incident energy. When the incident energy approaches the superconducting energy-gap function, the Andreev reflection with approximate all-angle perfect transmission happens regardless of the value of $α$. We also give the differential conductance in these two regimes and find that the differential conductance increases as the parameter $α$ increases generally. In addition, the $α$-T3 lattice-based Josephson current increases as $α$ increases. When the length of junction approaches zero, the critical Josephson currents in the different values of $α$ approach the same value.
description: 9 pages, 9 figures
Il Punto Organico: una storia italiana
Creators: name: Rossi, Paolo
Publisher: name: Università degli Studi di Milano
Year: 2015
Subjects: Reclutamento

description: Recruitment of professors and researchers by Italian public Universities is limited not only by the financial constraints imposed by National laws, but also by the conversion of the financial resources into positions according to a rule esatablished a few years ago by the Ministry of Education and espressed by the so-called  “Punto Organico” (P.O.).
The origin of the notion of P.O. is traced back to some statistical studies performed more than a decade ago . Its subsequent application to university recruiting follows from  a sequel of administrative actions taken by the Ministry but it is not based on an explicit (and formally required) legal formulation.
The recent structural evolution of the università system and some changes in the legislation have further weakened the justification for such a constraint.  An alternative (and legally consistent) mechanism for keeping under control the projected expenses  for personnel is proposed.
description: RT. A Journal on Research Policy and Evaluation, Vol 3, No 1 (2015)
On the Role of Entanglement in Schroedinger's Cat Paradox
Creators: name: Rinner, S.
name: Werner, E.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In this paper we re-investigate the core of Schroedinger's 'cat paradox'. We argue that one has to distinguish clearly between superpositions of macroscopic cat states and superpositions of entangled states which comprise both the state of the cat. It is shown, that in the first instance recurrence to decoherence or other mechanisms is not necessary in this special case in order to explain the absence of macroscopic superpositions. Additionally, we present modified versions of two quantum optical experiments as experimenta crucis. Applied rigorously, quantum mechanical formalism reduces the problem to a mere pseudo-paradox.
description: 10 pages; LaTeX; contact information updated
On the contact Ozsvath-Szabo invariant
Creators: name: Etgü, Tolga
name: Ozbagci, Burak
Publisher: name: arXiv
Year: 2007
Subjects: subject: Geometric Topology (math.GT)
subject: Symplectic Geometry (math.SG)
subject: FOS: Mathematics
subject: 57R17, 57R65, 57R58, 57M99

description: Sarkar and Wang proved that the hat version of Heegaard Floer homology group of a closed oriented 3-manifold is combinatorial starting from an arbitrary nice Heegaard diagram and in fact every closed oriented 3-manifold admits such a Heegaard diagram. Plamenevskaya showed that the contact Ozsvath-Szabo invariant is combinatorial once we are given an open book decomposition compatible with a contact structure. The idea is to combine the algorithm of Sarkar and Wang with the recent description of the contact Ozsvath-Szabo invariant due to Honda, Kazez and Matic. Here we simply observe that the hat version of the Heegaard Floer homology group and the contact Ozsvath-Szabo invariant in this group can be combinatorially calculated starting from a contact surgery diagram. We give detailed examples pointing out to some shortcuts in the computations.
description: 17 pages, 18 figures
Z-Sequence: Photometric redshift predictions for galaxy clusters with sequential random k-nearest neighbours
Creators: name: Chan, Matthew C.
name: Stott, John P.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We introduce Z-Sequence, a novel empirical model that utilises photometric measurements of observed galaxies within a specified search radius to estimate the photometric redshift of galaxy clusters. Z-Sequence itself is composed of a machine learning ensemble based on the k-nearest neighbours algorithm. We implement an automated feature selection strategy that iteratively determines appropriate combinations of filters and colours to minimise photometric redshift prediction error. We intend for Z-Sequence to be a standalone technique but it can be combined with cluster finders that do not intrinsically predict redshift, such as our own DEEP-CEE. In this proof-of-concept study we train, fine-tune and test Z-Sequence on publicly available cluster catalogues derived from the Sloan Digital Sky Survey. We determine the photometric redshift prediction error of Z-Sequence via the median value of $|Δz|/(1+z)$ (across a photometric redshift range of $0.05 \le \textit{z} \le 0.6$) to be $\sim0.01$ when applying a small search radius. The photometric redshift prediction error for test samples increases by 30-50 per cent when the search radius is enlarged, likely due to line-of-sight interloping galaxies. Eventually, we aim to apply Z-Sequence to upcoming imaging surveys such as the Legacy Survey of Space and Time to provide photometric redshift estimates for large samples of as yet undiscovered and distant clusters.
description: Accepted to MNRAS on 16th March 2021; pp. 1-21. Supplementary material is included; pp. 22-164
Uchch Shikshan Sansthanon Mein Patrakarita Evam Jansanchar Vishay Ke Shaikshanik Star Ka Adhyayan Evam Avalokan: Uttarakhand Rajya Ke Vishesh Sandarbh Mein"
Creators: name: Rajat Pandey
name: Prof. (Dr.) Sukhnandan Singh
Publisher: name: Zenodo
Year: 2025

description: "Uchch Shikshan Sansthanon Mein Patrakarita Evam Jansanchar Vishay Ke Shaikshanik Star Ka Adhyayan Evan Avalokan: Uttarakhand Rajya Ke Vishesh Sandarbh Mein"
Complex Langevin study for polarons in an attractively interacting one-dimensional two-component Fermi gas
Creators: name: Doi, Takahiro M.
name: Tajima, Hiroyuki
name: Tsutsui, Shoichiro
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: High Energy Physics - Lattice (hep-lat)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We investigate a polaronic excitation in a one-dimensional spin-1/2 Fermi gas with contact attractive interactions, using the complex Langevin method, which is a promising approach to evade a possible sign problem in quantum Monte Carlo simulations. We found that the complex Langevin method works correctly in a wide range of temperature, interaction strength, and population imbalance. The Fermi polaron energy extracted from the two-point imaginary Green's function is not sensitive to the temperature and the impurity concentration in the parameter region we considered. Our results show a good agreement with the solution of the thermodynamic Bethe ansatz at zero temperature.
description: 18 pages, 5 figures
Deeply virtual Compton scattering on a virtual pion target
Creators: name: Amrath, Daniela
name: Diehl, Markus
name: Lansberg, Jean-Philippe
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study deeply virtual Compton scattering on a virtual pion that is emitted by a proton. Using a range of models for the generalized parton distributions of the pion, we evaluate the cross section, as well as the beam spin and beam charge asymmetries in the leading-twist approximation. Studying Compton scattering on the pion in suitable kinematics puts high demands on both beam energy and luminosity, and we find that the corresponding requirements will first be met after the energy upgrade at Jefferson Laboratory. As a by-product of our study, we construct a parameterization of pion generalized parton distributions that has a non-trivial interplay between the x and t dependence and is in good agreement with form factor data and lattice calculations.
description: 23 pages, 9 figures
Diffuse Synchrotron Emission Associated with the Starburst in the Circumnuclear Disk of NGC 1275
Creators: name: Nagai, Hiroshi
name: Kawakatu, Nozomu
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Recent Atacama Large Millimeter/submillimeter Array (ALMA) observations found a positive correlation between the mass of dense molecular gas in the circumnuclear disks (CNDs) and accretion rate to the active galactic nuclei (AGNs). This indicates that star formation activity in the CNDs is essential for triggering the accretion of mass to AGNs. Although the starburst-driven turbulence is a key mechanism for the transfer of angular momentum and the resultant mass accretion from the CND scale to the inner radius, the observational evidence is lacking. We report the very-long-baseline-interferometry (VLBI) detection of the diffuse synchrotron emission on a scale of several tens-pc coinciding spatially with the molecular gas disk recently discovered by ALMA observations in NGC~1275. The synchrotron emissions are most likely resulted from the relativistic electrons produced by the supernova explosions. This is an unambiguous evidence of the star formation activity in a CND. The turbulent velocity and the scale height of the CND predicted from the supernova-driven turbulence model agree with the observations, although the model-predicted accretion rate disagrees with the bolometric luminosity. This might indicate that additional mechanisms to enhance the turbulence is required for the inner disk. We discuss the multiphase nature of the CND by combining the information of the CO emission, synchrotron emission, and free-free absorption.
description: 6 pages, 3 figures, Accepted for publication in ApJL
XMM-Newton observations of the eclipsing polar V2301 Oph
Creators: name: Ramsay, Gavin
name: Cropper, Mark
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present XMM-Newton observations of the eclipsing polar V2301 Oph which cover nearly 2.5 binary orbital cycles and 2 eclipses. This polar is believed to have the lowest magnetic field strength (7 MG) of any known polar. We find evidence for structure in the X-ray eclipse profile which shows a `standstill' feature lasting 26+/-4 sec. This allows us to place an upper limit on the mass of the white dwarf of ~1.2 Msun. We find no evidence for QPOs in the frequency range 0.02-10 Hz. This coupled with the absence of QPOs in RXTE data suggest that, if present, any oscillations in the shock front have a minimal effect on the resultant X-ray flux. We find no evidence for a distinct soft X-ray component in its spectrum - it therefore joins another 7 systems which do not show this component. We suggest that those systems which are asynchronous, have low mass transfer rates, or have accretion occurring over a relatively large fraction of the white dwarf are more likely to show this effect. We find that the specific mass transfer rate has to be close to 0.1 g cm^-2 s^-1 to predict masses which are consistent with that derived from our eclipse analysis. This maybe due to the fact that the low magnetic field strength allows accretion to take place along a wide range of azimuth.
description: Accepted MNRAS
19-F NMR Investigation of Iron-pnictide Superconductor LaFeAsO(0.89)F(0.11)
Creators: name: Ahilan, K.
name: Ning, F. L.
name: Imai, T.
name: Sefat, A. S.
name: Jin, R.
name: McGuire, M. A.
name: Sales, B. C.
name: Mandrus, D.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We report 19-F NMR investigation of the new high temperature superconductor LaFeAsO(0.89)F(0.11) (Tc ~ 28K). We demonstrate that low frequency spin fluctuations exhibit pseudo gap behavior above Tc. We also deduce the London penetration depth lambda from NMR line broadening below Tc.
description: Accepted for publication in Phys. Rev. B (Rapid) with the original submission date
East-West trade and the regional development of Siberia and the Soviet Far East
Creators: name: Bradshaw, Michael Joseph
Publisher: name: University of British Columbia
Year: 2010

description: Studies of the role of East-West trade in Soviet economic development often assume that Siberia and the Far East play an important role in trading relations, but few studies have examined the extent of that role and the relationship between trade and economic development within the region. This study addresses two interrelated questions: firstly, what is the role of Siberia and the Far East in trade with the West, and secondly, what is the role of East-West trade in Siberian development. Regional trade participation data are not available. The study therefore examines the composition of Soviet trade with the West and the industrial structure of the Siberian economy, in order to deduce the extent of regional participation in trade. Soviet exports to the West are dominated by natural resources, while imports from the West comprise machinery and equipment, manufactured goods and agricultural products. Analysis of the Siberian economy reveals a specialisation in the production and processing of natural resources. Estimates of export participation show that since the late 1970s the region has become the Soviet Union's most important source of foreign currency. Imports of Western technology are shown to play an important part in natural resource production and in the creation of Siberia's Territorial-Production Complexes. In many instances compensation agreements tie the use of imports to export production. Overall the value of Siberian exports exceeds the cost of imports of Western technology, so that the region generates a sizeable foreign currency surplus. In conclusion, a simple model of the trade and development process is presented which relates the pattern of foreign trade participation to the process of regional development. The impact of Western imports is felt mainly in the European core region where they provide additional resources to feed the population and renovate the industrial base; the impact of exports to the West is felt mainly in Siberia and the Far East where they increase demands for natural resource production. Thus, East-West trade serves to perpetuate the existing core-periphery pattern of Soviet regional development.
Exploring the benefits and risks of mentor self-disclosure: relationship quality and ethics in youth mentoring
Creators: name: Dutton, Hilary
name: Deane, Kelsey L.
name: Bullen, Pat
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Medicine
subject: Science Policy
subject: 111714 Mental Health
subject: FOS: Health sciences

description: Evidence shows that self-disclosure plays an important role in developing and maintaining close interpersonal relationships. As self-disclosure remains largely unexamined in the context of interventions based on youth-adult helping relationships, little is known about the effects of mentor disclosure, or the ethics of using this communication technique. In this study, we used self-report questionnaire data from 51 mentoring pairs to investigate the effect of mentor self-disclosure on relationship quality in youth mentoring relationships, and consider the ethical challenges that arise when helping adults disclose to young people. Bivariate correlations showed mentor self-disclosure was significantly associated with relationship quality for mentees, but not mentors. Qualitative content analysis showed mentors were aware of how their disclosure may have ethical implications associated with the age and role-appropriateness of topics, contradictions between their own and the mentees’ family or cultural values, and the potential to negatively influence mentee behaviour. We consider these findings in a context of ethics in youth mentoring to raise questions about the intersection of disclosure, relationship quality, and safe mentoring practice.
Does Geopolitics Have an Impact on Energy Trade? Empirical Research on Emerging Countries
Creators: name: Li, Fen
name: Yang, Cunyi
name: Li, Zhenghui
name: Failler, Pierre
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Economics (econ.GN)
subject: FOS: Economics and business

description: The energy trade is an important pillar of each country's development, making up for the imbalance in the production and consumption of fossil fuels. Geopolitical risks affect the energy trade of various countries to a certain extent, but the causes of geopolitical risks are complex, and energy trade also involves many aspects, so the impact of geopolitics on energy trade is also complex. Based on the monthly data from 2000 to 2020 of 17 emerging economies, this paper employs the fixed-effect model and the regression-discontinuity (RD) model to verify the negative impact of geopolitics on energy trade first and then analyze the mechanism and heterogeneity of the impact. The following conclusions are drawn: First, geopolitics has a significant negative impact on the import and export of the energy trade, and the inhibition on the export is greater than that on the import. Second, the impact mechanism of geopolitics on the energy trade is reflected in the lagging effect and mediating effect on the imports and exports; that is, the negative impact of geopolitics on energy trade continued to be significant 10 months later. Coal and crude oil prices, as mediating variables, decreased to reduce the imports and exports, whereas natural gas prices showed an increase. Third, the impact of geopolitics on energy trade is heterogeneous in terms of national attribute characteristics and geo-event types.
description: 23 Pages,16 Tables, 8 Figures
Optimal weighted partial decision combining for fading channel diversity
Creators: name: Kot, Alan Douglas
Publisher: name: University of British Columbia
Year: 2010

description: A diversity combining scheme is examined that utilizes a demodulator's hard decisions in conjunction with knowledge of each decision's reliability. A maximum-likelihood bit decision is made, based on these partial decisions from the demodulator and on measurements of the state of the fading channel. The technique is sub-optimal since hard decisions are processed, but it may find application in low cost receiver design. The technique is optimal in the sense that a minimum probability of bit error is achieved, given a set of partial decisions and knowledge of their reliability. Performance analysis for the case of non-coherent frequency shift keying on a slow Rayleigh fading channel with additive white Gaussian noise includes the derivation of a tight upper bound on the probability of bit error, and estimates of the asymptotic performance relative to standard diversity schemes such as majority-voting, selection diversity, square-law, and maximal ratio combining. These results are supported by simulation results for bit and packet error rates in an example system. With five independent bit repeats and a BER of 10⁻³, the receiver is about 3 dB more efficient than majority-voting, and about 1 dB more efficient than selection diversity. The gain in efficiency, relative to the standard partial decision combination schemes, increases with the number of repeats. The degradation in performance in a practical receiver implementation is addressed, and it is demonstrated that near ideal performance may be obtained with only a few reliability weights quantized to a small number of levels. Furthermore, this performance is maintained over a wide range of average signal to noise ratio without having to adapt the reliability weights. When the reliability estimate is corrupted by additive white Gaussian noise, it is demonstrated that simple low- pass filtering of the signal strength estimate is sufficient to obtain near ideal performance. The performance is degraded in the presence of cochannel interference, but for a moderate level of interference the performance is demonstrated to be superior to majority-voting or selection diversity. Other results include a method to estimate the optimal quantization thresholds, and a method to obtain the probability of error of selection diversity receivers employing signal to noise ratio measurement quantization. The selection diversity analysis is applicable to the more general case of Rician fading.
Polar Coding for Efficient Transport Layer Multicast
Creators: name: Pereira, Pablo Gil
name: Herfet, Thorsten
Publisher: name: arXiv
Year: 2022
Subjects: subject: Information Theory (cs.IT)
subject: Networking and Internet Architecture (cs.NI)
subject: FOS: Computer and information sciences

description: In this paper, we shed light on how an adaptive, efficient error coding in the transport layer helps ensure the application requirements. We recap the use of MDS codes and show that binary coding can significantly reduce the complexity and hence increase the applicability also for embedded devices. We exploit the persymmetric structure of the generator matrix in polar codes to establish a duality of dispersion over channels (the polarization effect) and over packets (the generality required for multicast transmission), thereby constructing systematic polar codes for incremental redundancy whose performance, despite a much lower complexity, is near to MDS codes for medium-range residual loss rates.
The earliest phases of high-mass star formation: a 3 square degree millimeter continuum mapping of Cygnus X
Creators: name: Motte, Frédérique
name: Bontemps, S.
name: Schilke, P.
name: Schneider, N.
name: Menten, K. M.
name: Broguière, D.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We have made an extensive 1.2mm continuum mosaicing study of the Cygnus X molecular cloud complex using the MAMBO cameras at the IRAM 30 m telescope. We then compared our mm maps with mid-IR images, and have made SiO(2-1) follow-up observations of the best candidate progenitors of high-mass stars. Our complete study of Cygnus X provides, for the first time, an unbiased census of massive young stellar objects. We discover 129 massive dense cores, among which 42 are probable precursors of high-mass stars. Our study qualifies 17 cores as good candidates for hosting massive IR-quiet protostars, while up to 25 cores potentially host high-luminosity IR protostars. We fail to discover the high-mass analogs of pre-stellar dense cores in CygnusX, but find several massive starless clumps that might be gravitationally bound. Since our sample is derived from a single molecular complex and covers every embedded phase of high-mass star formation, it gives the first statistical estimates of their lifetime. In contrast to what is found for low-mass class 0 and class I phases, the IR-quiet protostellar phase of high-mass stars may last as long as their better-known high-luminosity IR phase. The statistical lifetimes of high-mass protostars and pre-stellar cores (~ 3 x 10^4 yr and < 10^3 yr) in Cygnus X are one and two order(s) of magnitude smaller, respectively, than what is found in nearby, low-mass star-forming regions. We therefore propose that high-mass pre-stellar and protostellar cores are in a highly dynamic state, as expected in a molecular cloud where turbulent processes dominate.
description: 32 pages, 62 figures to be published in Astronomy & Astrophysics journal
Interacting Higher Spins and the High Energy Limit of the Bosonic String
Creators: name: Fotopoulos, A.
name: Tsulaia, M.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this note, we construct a BRST invariant cubic vertex for massless fields of arbitrary mixed symmetry in flat space-time. The construction is based on the vertex given in bosonic Open String Field Theory. The algebra of gauge transformations is closed without any additional, higher than cubic, couplings due to the presence of an infinite tower of massless fields. We briefly discuss the generalization of this result to a curved space-time and other possible implications.
description: Published Version; typos corrected, references added; (v3) Some typos corrected and a minor clarification about eq. (3.29)
Confirmation and physical characterization of the new bulge globular cluster Patchick 99 from the VVV and Gaia surveys
Creators: name: Garro, E. R.
name: Minniti, D.
name: Gómez, M.
name: Alonso-García, J.
name: Palma, T.
name: Smith, L. C.
name: Ripepi, V.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Globular clusters (GCs) are important tools to understand the formation and evolution of the Milky Way (MW). The known MW sample is still incomplete, so the discovery of new GC candidates and the confirmation of their nature are crucial for the census of the MW GC system. Our goal is to confirm the physical nature of two GC candidates: Patchick99 and TBJ3, located towards the Galactic bulge. We use public data in the near-IR from the VVV, VVVX and 2MASS along the with deep optical data from the Gaia DR2, in order to estimate their main physical parameters: reddening, extinction, distance, luminosity, mean cluster proper motions (PMs), size, metallicity and age. We investigate both candidates at different wavelengths. We use near-IR and optical CMDs in order to analyse Patchick99. We decontaminate CMDs following a statistical procedure and PM-selection. Reddening and extinction are derived by adopting reddening maps. Metallicity and age are evaluated by fitting stellar isochrones. Reddening and extinction are E(J-Ks)=0.12+/-0.02 mag, AKs=0.09+/-0.01 mag from the VVV data, whereas E(BP-RP)=0.21+/-0.03 mag, AG=0.68+/-0.08 mag from Gaia DR2. We estimate a distance d=6.4+/-0.2 kpc in near-IR and D=7.0+/-0.2 kpc in optical. We derive its metallicity and age fitting PARSEC isochrones, finding [Fe/H]=-0.2+/-0.2 dex and t=10+/-2 Gyr. The mean PMs for Patchick99 are pmRA=-298+/-1.74 mas/yr and pmDEC=-5.49+/-2.02 mas/yr. We confirm that it is a low-luminosity GC, with MKs=-7.0+/-0.6 mag. The radius estimation is performed building the radial density profile, finding r~10'. We recognise 7 RR Lyrae star members within 8.2 arcmin from its centre, confirming the distance found by other methods. We found that TBJ3 shows mid-IR emissions that are not present in GCs. We discard TBJ3 as GC candidate and we focus on Patchick99. We conclude that it is an old metal-rich GC, situated in the Galactic bulge.
description: 13 pages, 14 figures, accepted in Astronomy & Astrophysics Journal
Possible Competing Order-Induced Fermi Arcs in Cuprate Superconductors
Creators: name: Yu, B. -L.
name: Wang, J. C. F.
name: Beyer, A. D.
name: Teague, M. L.
name: Lockhart, G. P.
name: Horng, J. S. A.
name: Lee, S. -P.
name: Yeh, N. -C.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We investigate the scenario of competing order (CO) induced Fermi arcs and pseudogap in cuprate superconductors. For hole-type cuprates, both phenomena as a function of temperature and doping level can be accounted for if the CO vanishes at $T^{\ast}$ above the superconducting transition $T_c$ and the CO wave-vector Q is parallel to the antinodal direction. In contrast, the absence of these phenomena and the non-monotonic d-wave gap in electron-type cuprates may be attributed to $T^{\ast} < T_c$ and a CO wave-vector Q parallel to the nodal direction.
description: 6 pages and 5 figures, with one figure added in the updated version. Accepted for publication in Solid State Communications, Fast Communications. Corresponding author: Nai-Chang Yeh (ncyeh@caltech.edu)
Locating the inner edge of neutron star crust using terrestrial nuclear laboratory data
Creators: name: Xu, Jun
name: Chen, Lie-Wen
name: Li, Bao-An
name: Ma, Hong-Ru
Publisher: name: arXiv
Year: 2008
Subjects: subject: Nuclear Theory (nucl-th)
subject: Astrophysics (astro-ph)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: Within both dynamical and thermodynamical approaches using the equation of state for neutron-rich nuclear matter constrained by the recent isospin diffusion data from heavy-ion reactions in the same sub-saturation density range as the neutron star crust, the density and pressure at the inner edge separating the liquid core from the solid crust of neutron stars are determined to be 0.040 fm$^{-3}$ $\leq ρ_{t}\leq 0.065$ fm$^{-3}$ and 0.01 MeV/fm$^{3}$ $\leq P_{t}\leq 0.26$ MeV/fm$^{3}$, respectively. These together with the observed minimum crustal fraction of the total moment of inertia allow us to set a new limit for the radius of the Vela pulsar significantly different from the previous estimate. It is further shown that the widely used parabolic approximation to the equation of state of asymmetric nuclear matter leads systematically to significantly higher core-crust transition densities and pressures, especially with stiffer symmetry energy functionals.
description: 6 pages, 4 figures, section heads added and typos fixed, version to appear in PRC
A Machine Learning Framework for Real-time Inverse Modeling and Multi-objective Process Optimization of Composites for Active Manufacturing Control
Creators: name: Humfeld, Keith D.
name: Gu, Dawei
name: Butler, Geoffrey A.
name: Nelson, Karl
name: Zobeiry, Navid
Publisher: name: arXiv
Year: 2021
Subjects: subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: For manufacturing of aerospace composites, several parts may be processed simultaneously using convective heating in an autoclave. Due to uncertainties including tool placement, convective Boundary Conditions (BCs) vary in each run. As a result, temperature histories in some of the parts may not conform to process specifications due to under-curing or over-heating. Thermochemical analysis using Finite Element (FE) simulations are typically conducted prior to fabrication based on assumed range of BCs. This, however, introduces unnecessary constraints on the design. To monitor the process, thermocouples (TCs) are placed under tools near critical locations. The TC data may be used to back-calculate BCs using trial-and-error FE analysis. However, since the inverse heat transfer problem is ill-posed, many solutions are obtained for given TC data. In this study, a novel machine learning (ML) framework is presented capable of optimizing air temperature cycle in real-time based on TC data from multiple parts, for active control of manufacturing. The framework consists of two recurrent Neural Networks (NN) for inverse modeling of the ill-posed curing problem at the speed of 300 simulations/second, and a classification NN for multi-objective optimization of the air temperature at the speed of 35,000 simulations/second. A virtual demonstration of the framework for process optimization of three composite parts with data from three TCs is presented.
Does energy efficiency affect ambient PM2.5? The moderating role of energy investment
Creators: name: Yang, Cunyi
name: Li, Tinghui
name: Albitar, Khaldoon
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Economics (econ.GN)
subject: FOS: Economics and business

description: The difficulty of balance between environment and energy consumption makes countries and enterprises face a dilemma, and improving energy efficiency has become one of the ways to solve this dilemma. Based on data of 158 countries from 1980 to 2018, the dynamic TFP of different countries is calculated by means of the Super-SBM-GML model. The TFP is decomposed into indexes of EC (Technical Efficiency Change), TC (Technological Change) and EC has been extended to PEC (Pure Efficiency Change) and SEC (Scale Efficiency Change). Then the fixed effect model and fixed effect panel quantile model are used to analyze the moderating effect and exogenous effect of energy efficiency on PM2.5 concentration on the basis of verifying that energy efficiency can reduce PM2.5 concentration. We conclude, first, the global energy efficiency has been continuously improved during the sample period, and both of technological progress and technical efficiency have been improved. Second, the impact of energy efficiency on PM2.5 is heterogeneous which is reflected in the various elements of energy efficiency decomposition. The increase of energy efficiency can inhibit PM2.5 concentration and the inhibition effect mainly comes from TC and PEC but SEC promotes PM2.5 emission. Third, energy investment plays a moderating role in the environmental protection effect of energy efficiency. Fourth, the impact of energy efficiency on PM2.5 concentration is heterogeneous in terms of national attribute, which is embodied in the differences of national development, science & technology development level, new energy utilization ratio and the role of international energy trade.
description: 27 Pages, 11 Tables, 2 Figures
A new approach to the exact solutions of the effective mass Schrodinger equation
Creators: name: Tezcan, Cevdet
name: Sever, Ramazan
name: Yesiltas, Ozlem
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Effective mass Schrodinger equation is solved exactly for a given potential. Nikiforov-Uvarov method is used to obtain energy eigenvalues and the corresponding wave functions. A free parameter is used in the transformation of the wave function. The effective mass Schrodinger equation is also solved for the Morse potential transforming to the constant mass Schrödinger equation for a potential. One can also get solution of the effective mass Schrodinger equation starting from the constant mass Schrodinger equation.
description: 14 pages
Accretion of Dark Matter onto a Moving Schwarzschild Black Hole: An Exact Solution
Creators: name: Mach, Patryk
name: Odrzywolek, Andrzej
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We investigate accretion of dark matter onto a moving Schwarzschild black hole. The dark matter is modeled by the collisionless Vlasov gas, assumed to be in thermal equilibrium at infinity. We derive an exact stationary solution and provide a compact formula for the mass accretion rate. In general, the mass accretion rate is a nonmonotonic function of the black hole velocity. A monotonic relation (the accretion rate proportional to the Lorentz factor associated with the velocity of the black hole) is obtained for high asymptotic temperatures of the gas. The derived accretion rates are relevant for the growth of primordial black holes in the early Universe.
description: 6 pages, 1 figure, to appear in Phys. Rev. Lett
The evolving starburst-AGN connection: Implications for SKA and its pathfinders
Creators: name: Norris, Ray
name: Middelberg, Enno
name: Boyle, Brian
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: How well is the modern-day starburst-AGN connection mirrored in the early Universe? This is starting to be answered by deep wide radio surveys such as ATLAS, which are giving us a new view of high redshift galaxies. For example, we find powerful radio-loud AGNs which look like star-forming spirals in the optical and infrared, a composite which is almost unknown in the modern Universe. We find radio-bright objects which are unexpectedly invisible in the infrared, and which may be very high redshift radio galaxies and quasars. And although the radio-far-infrared correlation for star-forming galaxies has now been extended down to microJy levels, we still cannot reliably distinguish between starburst and AGN. So what do we need to do to ensure that SKA and its pathfinders will be able to understand galaxy evolution in the early Universe?
description: In From Planets to Dark Energy: the Modern Radio Universe, ed R. Beswick, accepted
Antimagic labelings of regular bipartite graphs: An application of the Marriage Theorem
Creators: name: Cranston, Daniel W.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: A labeling of a graph is a bijection from $E(G)$ to the set $\{1, 2,..., |E(G)|\}$. A labeling is \textit{antimagic} if for any distinct vertices $u$ and $v$, the sum of the labels on edges incident to $u$ is different from the sum of the labels on edges incident to $v$. We say a graph is antimagic if it has an antimagic labeling. In 1990, Ringel conjectured that every connected graph other than $K_2$ is antimagic. In this paper, we show that every regular bipartite graph (with degree at least 2) is antimagic. Our technique relies heavily on the Marriage Theorem.
description: 9 pages
The dust temperatures of the prestellar cores in the rho Oph main cloud and in other star forming regions: consequences for the core mass function
Creators: name: Stamatellos, D.
name: Whitworth, A. P.
name: Ward-Thompson, D.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We estimate the dust temperatures of the clumps in the rho Oph main cloud taking into account the 3D geometry of the region, and external heating from the interstellar radiation field and from HD147879,a nearby luminous B2V star, which is believed to dominate the radiation field in the region. We find that the regions where prestellar cores are observed (i.e. at optical visual extinctions >7 mag) are colder than ~10-11K. These dust temperatures are smaller than those which previous studies of the same region have assumed. We use the new dust temperatures to estimate the masses of the prestellar cores in the rho Oph main cloud from mm observations, and we find core masses that are larger than previous estimates by a factor of ~2-3. This affects the core mass function (CMF) of the region; we find that the mass at which the core mass spectrum steepens from a slope alpha~1.5 to a slope alpha~2.5 has moved from ~0.5 Msun to ~1Msun. In contrast with the CMF in other star forming regions (e.g. Orion), there is no indication for a turnover down to the completeness limit (~0.2Msun), but the CMF may flatten at around ~0.4Msun. We generalize our results to the prestellar cores in Taurus and in Orion. In Taurus the ambient radiation field heating the prestellar cores is believed to be weaker than than that in rho Oph. Hence, the dust temperatures of the cores in Taurus are expected to be below ~ 10-11 K.In Orion the radiation field is believed to be 10^3 times stronger than the standard interstellar radiation field. Based on this assumption we estimate that the dust temperatures of the prestellar cores in Orion are around ~20-30K.
description: MNRAS accepted