cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
The Uncertainty Relation in "Which-Way" Experiments: How to Observe Directly the Momentum Transfer using Weak Values
Creators: name: Garretson, J. L.
name: Wiseman, H. M.
name: Pope, D. T.
name: Pegg, D. T.
Publisher: name: arXiv
Year: 2003
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: A which-way measurement destroys the twin-slit interference pattern. Bohr argued that distinguishing between two slits a distance s apart gives the particle a random momentum transfer \wp of order h/s. This was accepted for more than 60 years, until Scully, Englert and Walther (SEW) proposed a which-way scheme that, they claimed, entailed no momentum transfer. Storey, Tan, Collett and Walls (STCW) in turn proved a theorem that, they claimed, showed that Bohr was right. This work reviews and extends a recent proposal [Wiseman, Phys. Lett. A 311, 285 (2003)] to resolve the issue using a weak-valued probability distribution for momentum transfer, P_wv(\wp). We show that P_wv(\wp) must be wider than h/6s. However, its moments can still be zero because P_wv(\wp) is not necessarily positive definite. Nevertheless, it is measurable in a way understandable to a classical physicist. We introduce a new measure of spread for P_wv(\wp): half of the unit-confidence interval, and conjecture that it is never less than h/4s. For an idealized example with infinitely narrow slits, the moments of P_wv(\wp) and of the momentum distributions are undefined unless a process of apodization is used. We show that by considering successively smoother initial wave functions, successively more moments of both P_wv(\wp) and the momentum distributions become defined. For this example the moments of P_wv(\wp) are zero, and these are equal to the changes in the moments of the momentum distribution. We prove that this relation holds for schemes in which the moments of P_wv(\wp) are non-zero, but only for the first two moments. We also compare these moments to those of two other momentum-transfer distributions and \hat{p}_f-\hat{p}_i. We find agreement between all of these, but again only for the first two moments.
description: 14 pages, 6 figures, submitted to J. Opt. B
Ab initio Simulations of Fe-based Ferric Wheels
Creators: name: Postnikov, A. V.
name: Kortus, Jens
name: Bluegel, Stefan
Publisher: name: arXiv
Year: 2003
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Based on first-principles density-functional theory calculations we investigate the electronic structure of hexanuclear "ferric wheels" M Fe_6[N(CH_2 CH_2 O)_3]_6 Cl (M = Li, Na) in their antiferromagnetic ground state. The electronic structure is presented in form of spin- and site-resolved local densities of states. The latter clearly indicate that the magnetic moment is distributed over several sites. The local moment at the iron site is still the largest one with about 4 mu_B, thus indicating the valence state of iron to be closer to Fe(II) than to commonly accepted Fe(III). The local spin of S=5/2 per iron site, following from magnetization measurements, is perfectly reproduced if one takes the moments on the neighbor atoms into account. The largest magnetic polarization is found on the apical oxygen atom, followed by nitrogen bridging oxygens. These findings are confirmed by a map of spatial spin density. A further goal of the present study has been a comparative test of two different DFT implementations, Siesta and NRLMOL. They yield a very good agreement down to small details in the electronic structure.
description: 10 pages, 3 embedded postscript figures, to be published in Molecular Physics Reports (proceedings of the Summer School on New Magnetics - Bedlewo, Poland, September 2003). Two references updated
Coronavirus Optimization Algorithm: A bioinspired metaheuristic based on the COVID-19 propagation model
Creators: name: Martínez-Álvarez, F.
name: Asencio-Cortés, G.
name: Torres, J. F.
name: Gutiérrez-Avilés, D.
name: Melgar-García, L.
name: Pérez-Chacón, R.
name: Rubio-Escudero, C.
name: Riquelme, J. C.
name: Troncoso, A.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: A novel bioinspired metaheuristic is proposed in this work, simulating how the coronavirus spreads and infects healthy people. From an initial individual (the patient zero), the coronavirus infects new patients at known rates, creating new populations of infected people. Every individual can either die or infect and, afterwards, be sent to the recovered population. Relevant terms such as re-infection probability, super-spreading rate or traveling rate are introduced in the model in order to simulate as accurately as possible the coronavirus activity. The Coronavirus Optimization Algorithm has two major advantages compared to other similar strategies. First, the input parameters are already set according to the disease statistics, preventing researchers from initializing them with arbitrary values. Second, the approach has the ability of ending after several iterations, without setting this value either. Infected population initially grows at an exponential rate but after some iterations, when considering social isolation measures and the high number recovered and dead people, the number of infected people starts decreasing in subsequent iterations. Furthermore, a parallel multi-virus version is proposed in which several coronavirus strains evolve over time and explore wider search space areas in less iterations. Finally, the metaheuristic has been combined with deep learning models, in order to find optimal hyperparameters during the training phase. As application case, the problem of electricity load time series forecasting has been addressed, showing quite remarkable performance.
description: 30 pages, 4 figures
Ceralocyna variegata Monne and Napp 1999
Creators: name: Clarke, Robin
name: Zamalloa, Sonia
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Cerambycidae
Ceralocyna
Ceralocyna variegata

description: Ceralocyna variegata Monné and Napp, 1999
 Dept. Santa Cruz. 17°29′96″S/ 63°39′13″W, 430 m, 5 km SSE of Buena Vista, Hotel Flora and Fauna: on/flying to flowers of “ Red Powder Puff ”, male, 4.VII.2005 (RCSZ); on/flying to flowers of “ Barbasquillo ”, 2 females, 12+ 18.VIII.2005 (RCSZ); on/flying to flowers of “Turere”, female, 7.X.2005 (RCSZ).
 Remarks. In all these specimens the legs are entirely black; the vermillion areas dark (the sides of prothorax inconspicuously so); but in both sexes the form of the genae and most of the other characters correspond to the original description.
description: Published as part of Clarke, Robin & Zamalloa, Sonia, 2018, Bolivian anthophilous Cerambycinae (Coleoptera: Cerambycidae) host flower records, pp. 1-35 in Insecta Mundi 2018 (640) on page 23, DOI: 10.5281/zenodo.4645968
A refinement of the complex convexity theorem via symplectic techniques
Creators: name: Kroetz, Bernhard
name: Otto, Michael
Publisher: name: arXiv
Year: 2004
Subjects: subject: Symplectic Geometry (math.SG)
subject: FOS: Mathematics

description: We apply techniques from symplectic geometry to extend and give a new proof of the complex convexity theorem of Gindikin-Kroetz.
description: 10 pages
A Comparative Analysis of Different Monte Carlo Methods
Creators: name: Matyas, Laszlo
name: Harris, Mark
name: Matyas, Laszlo
name: Harris, Mark
Publisher: name: Unknown
Year: 1993
Subjects: subject: Research Methods/ Statistical Methods
subject: Monte Carlo experiment
subject: Simulation
subject: Estimation
subject: Durbin—Watson test

description: The purpose of this paper is to investigate how different ways to generate data in a Monte Carlo experiment can influence the outcome of an analysis.
title: The extrusion limits, parameters and microstructures of aluminium 2014 solid and powder.
Creators: name: Shi, Heying
Publisher: name: The Open University
Year: 1990

description: Solid and powdered Al-2014 alloy extrusions, heat transfer during compaction, temperature changes during extrusion, microstructures of extrusion products, hot torsion and plane strain compression tested specimens have been extensively investigated. Estimation of maximum and minimum pressure allows the prediction of the possibility of an extrusion and the amount of heat transferred from mechanical work to be obtained. Temperature changes during extrusion have a major effect on the extrusion pressure, microstructure and quality of the products. Temperature changes are mainly in two stages: compaction and steady-state and a numerical model of these stages has been developed. Hot torsion and plane strain compression data has been analysed and this data is used to predict the shear stress at any temperature and strain rate by using hot working theory. The minimized extrusion pressure may then be obtained by upper-bound solution. Microstructures of hot torsion, plane strain compression and extrusion have been extensively examined. ATLASES of microstructures at hot working condition for both solid and powdered material have been created. The thermal model has been shown to be essential for the fundamental prediction of hot shortness limits and for the comparison of microstructures between extrusion and metal working tests.
Η δημογραφική γήρανση, πρόκληση ή απειλή; (Demographic aging, challenge or threat?) DEMONEWS, 38, 2020
Creators: name: BYRON KOTZAMANIS
Publisher: name: figshare
Year: 2021
Subjects: subject: 160399 Demography not elsewhere classified
subject: FOS: Sociology

description: A topic of intense concern during the interwar period in some Western European countries with the 'early' appearance of the mechanisms of demographic transition, demographic aging (i.e. the constant increase in the proportion of older people in the population) is still emerging as one of the main concerns in all the developed countries worldwide. Thus, a demographic phenomenon of the restructuring of population structures by age, progressively falls into one of the major problems (as a problem of economic and social organization) that our developed societies have to solve during the first half of the present century.In this article, we outline the evolution of demographic aging in Greece as well as the main factors (fertility decline, life expectancy increase) that have led to an increase in the population and a rising of the proportion of the elderly in the general population. We are also looking at the irreversible path of aging in the coming decades (an increase in 2040 of population 65+ years by 450,000, a decline of population 20-64 years by 1 million and a reduction of population 0-19 year by 450,000), a course that will leading to a significant increase in the demographic ratio of 65 + / 20-64 years, as in 2040 there will be 52 people aged 65 and over in 100 people 20-64, compared to 37 in 2018.
Θέμα έντονων προβληματισμών και ανησυχιών στη διάρκεια του μεσοπολέμου σε ορισμένες δυτικοευρωπαϊκές χώρες με «πρώιμη» εμφάνιση των μηχανισμών της δημογραφικής μετάβασης, η δημογραφική γήρανση (η συνεχής δηλαδή αύξηση της αναλογίας των ηλικιωμένων στον πληθυσμό) αναδύεται ως ένα από τα κύρια θέματα προβληματισμού σε όλες πλέον τις ανεπτυγμένες χώρες του πλανήτη μας. Ένα δημογραφικό φαινόμενο αναδιάρθρωσης των δομών του πληθυσμού κατά ηλικία ανάγεται έτσι προοδευτικά σε ένα από τα βασικότερα προβλήματα (ως πρόβλημα» οικονομίας και κοινωνικής οργάνωσης), που καλούνται να επιλύσουν οι ανεπτυγμένες κοινωνίες μας στη διάρκεια του πρώτου μισού του αιώνα μας.Στο άρθρο αυτό, εκθέτουμε την εξέλιξη της δημογραφικής γήρανσης στη χώρας μας ως και τους κύριους παράγοντες (πτώση της γονιμότητάς, αύξηση του προσδόκιμου ζωής) που οδήγησαν στην αύξηση του πλήθους και της αναλογίας των ηλικιωμένων στο συνολικό πληθυσμό. Εξετάζουμε ταυτόχρονα και την μη αναστρέψιμη πορεία της γήρανσης τις επόμενες δεκαετίες (αύξηση το 2040 των άνω των 65 ετών κατά 450 χιλ, μείωση των 20-64 ετών κατά 1 εκατομμύριο ως και των 0-19 ετών κατά 450 χιλιάδες), μια πορεία που θα οδηγήσει σε μια σημαντική αύξηση του δημογραφικού λόγου 65+/20-64 ετών, καθώς το 2040 θα αντιστοιχούν 52 άτομα ηλικίας 65 ετών και άνω σε 100 άτομα 20-64 ετών, έναντι 37 το 2018.
Systematic errors in direct state measurements with quantum controlled measurements
Creators: name: Ho, Le Bin
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Von Neumann measurement framework describes a dynamic interaction between a target system and a probe. In contrast, a quantum controlled measurement framework uses a qubit probe to control the actions of different operators on the target system, and convenient for establishing universal quantum computation. In this work, we use a quantum controlled measurement framework for measuring quantum states directly. We introduce two types of the quantum controlled measurement framework and investigate the systematic error (the bias between the true value and the estimated values) that caused by these types. We numerically investigate the systematic errors, evaluate the confidence region, and investigate the effect of experimental noise that arises from the imperfect detection. Our analysis has important applications in direct quantum state tomography.
description: 9 pages, 6 figures
A Note on Absolute Derivations and Zeta Functions
Creators: name: Lagarias, Jeffrey C.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Number Theory (math.NT)
subject: Algebraic Geometry (math.AG)
subject: Spectral Theory (math.SP)
subject: FOS: Mathematics
subject: 11M26, 11G99, 14G99

description: This comment answers a question raised by Kurokawa, Ochiai and Wakayama whether a certain operator constructed using a notion of quantum non-commutativity of primes has eigenvalues related to the Riemann zeta zeros.
description: 6 pages, latex; v2 title change, small text changes
Stream development at Wesbrook Place, UBC
Creators: name: Weddell, Angelena
Publisher: name: The University of British Columbia
Year: 2014

description: Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report.”
Additional Boundary Condition for the Wire Medium
Creators: name: Silveirinha, Mario G.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: In this paper, it is proved that the continuity of the tangential components of the average electric and magnetic fields is insufficient to describe the reflection of plane waves by a set of thin parallel wires embedded in a dielectric host using a homogenization approach. It is shown that an additional boundary condition is required to conveniently model a slab of the homogenized metamaterial. In order to understand how the different electromagnetic modes are excited at the interface, the problem of reflection of a plane wave by a set of semi-infinite parallel wires is solved analytically within the thin-wire approximation. Based on the derived result and other arguments, a new boundary condition is proposed for the homogenized wire medium. Extensive numerical simulations support our theoretical analysis, and show that when the additional boundary condition is considered the agreement between full wave results and homogenization theory is very good even for wavelengths comparable with the lattice constant.
Epidemic processes with immunization
Creators: name: Jimenez-Dalmaroni, Andrea
name: Hinrichsen, Haye
Publisher: name: arXiv
Year: 2003
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Quantitative Biology (q-bio)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: We study a model of directed percolation (DP) with immunization, i.e. with different probabilities for the first infection and subsequent infections. The immunization effect leads to an additional non-Markovian term in the corresponding field theoretical action. We consider immunization as a small perturbation around the DP fixed point in d<6, where the non-Markovian term is relevant. The immunization causes the system to be driven away from the neighbourhood of the DP critical point. In order to investigate the dynamical critical behaviour of the model, we consider the limits of low and high first infection rate, while the second infection rate remains constant at the DP critical value. Scaling arguments are applied to obtain an expression for the survival probability in both limits. The corresponding exponents are written in terms of the critical exponents for ordinary DP and DP with a wall. We find that the survival probability does not obey a power law behaviour, decaying instead as a stretched exponential in the low first infection probability limit and to a constant in the high first infection probability limit. The theoretical predictions are confirmed by optimized numerical simulations in 1+1 dimensions.
description: 12 pages, 11 figures. v.2: minor corrections
Realization and transport investigation of a single layer-twisted bilayer graphene junction
Creators: name: Rui, Dingran
name: Sun, Luzhao
name: Kang, N.
name: Li, Jiayu
name: Lin, Li
name: Peng, Hailin
name: Liu, Zhongfan
name: Xu, H. Q.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We report on low-temperature transport study of a single layer graphene (SLG)-twisted bilayer graphene (tBLG) junction device. The SLG-tBLG junction in the device is grown by chemical vapor deposition and the device is fabricated in a Hall-bar configuration on Si/SiO$_2$ substrate. The longitudinal resistances across the SLG-tBLG junction (cross-junction resistances) on the two sides of the Hall bar and the Hall resistances of SLG and tBLG in the device are measured. In the quantum Hall regime, the measurements show that the measured cross-junction resistances exhibit a series of new quantized plateaus and the appearance of these resistance plateaus can be attributed to the presence of the well-defined edge-channel transport along the SLG-tBLG junction interface. The measurements also show that the difference between the cross-junction resistances measured on the two sides of the Hall-bar provides a sensitive measure to the edge channel transport characteristics in the two graphene layers that constitute the SLG-tBLG junction and to degeneracy lifting of the Landau levels in the tBLG layer. Temperature dependent measurements of the cross-junction resistance in the quantum Hall regime are also carried out and the influence of the transverse transport of the bulk Landau levels on the edge channel transport along the SLG-tBLG junction interface are extracted. These results enrich the understanding of the charge transport across interfaces in graphene hybrid structures and open up new opportunities for probing exotic quantum phenomena in graphene devices.
description: 20 pages, 4 figures
title: Mathematical Modelling of the Effects of Health Interventions on the Evolution of Life History in Disease-Causing Organisms
Creators: name: Lynch, Penelope Anne
Publisher: name: The Open University
Year: 2013

description: We use mathematical models to explore the evolutionary implications of health interventions affecting age-dependent mortality schedules in two contexts, antihelminthics targeting parasitic nematodes, and programs directed against malaria vectors. We show that interventions targeting parasitic nematodes can exert selection pressure to either shorten or extend the time to maturity, depending on the details of worm mortality functions with and without the intervention. Interventions may therefore generate selection favouring later-maturing, larger and more fecund worms, rather than inevitably favouring the evolution of smaller, less fecund and hence potentially clinically less damaging worms as previously assumed. The evolution of insecticide-resistant mosquitoes threatens conventional public health programs targeting malaria vectors. By exploiting the high mortality rates of wild mosquitoes and the delay between malaria infection and infectiousness in mosquito hosts, late-life-acting (LLA) insecticides which kill only older mosquitoes can in principle provide effective transmission control in combination with very low selection for resistance. We develop a novel mathematical model to evaluate the potential of such pesticides and find that theoretical LLAs which affect only mosquitoes above a specific age can offer transmission control comparable with conventional insecticides, combined with very low selection for resistance. Benefits are maximised by generating lower mortality in mosquitoes not infected with malaria, and contacting and killing mosquitoes prior to biting. We also explore the optimum virulence characteristics for a fungal LLA biopesticide, and find that it may offer improved transmission reduction as well as lower selection for resistance when compared to some insecticides in current use. Lastly we use our model to assess a candidate for development as a chemical LLA. Finally, we explore a disparity between our model results and the conventional wisdom that a rare, recessive resistance allele will not spread. We find that the assumption of discrete, non-overlapping generations is key in this context.
Centrality dependence of charged-particle pseudorapidity distributions from d+Au collisions at sqrt(s_{NN})=200 GeV
Creators: name: BRAHMS Collaboration
name: Arsene, I.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: Charged-particle pseudorapidity densities are presented for the d+Au reaction at sqrt{s_{NN}}=200 GeV with -4.2 <= eta <= 4.2$. The results, from the BRAHMS experiment at RHIC, are shown for minimum-bias events and 0-30%, 30-60%, and 60-80% centrality classes. Models incorporating both soft physics and hard, perturbative QCD-based scattering physics agree well with the experimental results. The data do not support predictions based on strong-coupling, semi-classical QCD. In the deuteron-fragmentation region the central 200 GeV data show behavior similar to full-overlap d+Au results at sqrt{s_{NN}}=19.4 GeV.
description: 4 pages, 3figures; expanded discussion of uncertainties; added 60-80% centrality range; added additional discussion on centrality selection bias
title: Leukocyte HMGB1 Guides Neoangiogenesis in Regenerating Skeletal Muscle
Creators: name: Campana, Lara
Publisher: name: The Open University
Year: 2012

description: HMGB1 is ubiquitously present in the cell nucleus and highly conserved among species. It is released by necrotic cells and actively secreted by immune cells in the extracellular environment, where it behaves as a DAMP (Damage-Associate Molecular Pattern). Up to now all studies addressing the role of HMGB1 in wound healing have been carried out either in vitro or using pharmacological inhibitors. To assess the relative contribution of leukocyte HMGB1 and of passively released HMGB1 we have set up an ad hoc animal model. In this system, haematopoietic cells selectively lack HMGB1 by transplanting Hmgb1+/+ or Hmgb1-/- foetal livers into WT recipients. The role of leukocyte HMGB1 in tissue repair has been analyzed after skeletal muscle damage. I have used histological and magnetic resonance imaging (MRI) to non-invasively evaluate muscle inflammation and tissue architecture. In the absence of Hmgbl, there is a lower number of regenerating fibres at day7 after injury and an aberrant repair with smaller fibres at day 15. In vitro no differential effects of Hmgb1-/- and Hmgb1+/+ macrophages are detected on satellite cells differentiation/fusion, suggesting that events taking place in vivo are independent of the direct macrophage/satellite cell cross talk. No obvious differences are observed in the extent of leukocyte infiltration, as assessed both by cytofluorimetric and MRI analysis, suggesting that leukocyte Hmgb1 is not required for the attraction of inflammatory cells. qPCR unveils a role for leukocyte Hmgb1 in the production of angiogenic stimuli such as Ang2 and TNFα, probably in a hypoxia-dependent manner. Accordingly, the number of CD31 cells is dramatically reduced in the absence of leukocyte Hmgb1. Collectively our data suggest that HMGB1 secreted by leukocytes guides muscle regeneration through a paracrine role on vascular bed reconstitution.
Boundary Inflation and the WMAP Data
Creators: name: Ringeval, Christophe
name: Brax, Philippe
name: van de Bruck, Carsten
name: Davis, Anne-Christine
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Inflation in a five-dimensional brane world model with two boundary branes is studied. We make use of the moduli space approximation whereby the low energy theory reduces to a four-dimensional biscalar-tensor gravity plus a minimally coupled scalar field. After a detailed analysis of the inflationary solutions, we derive the evolution equations of the linear perturbations separating the adiabatic mode from two entropy modes. We then examine the primordial scalar and tensor power spectra and show that their tilt depends on the scalar-tensor coupling constant. Finally, the induced CMB anisotropies are computed and we present a Monte Carlo Markov Chains exploration of the parameter space using the first year WMAP data. We find a marginalized probability bound for the associated Eddington parameter at the end of inflation 1 - gamma < 0.002, at 95% confidence level. This suggests that future CMB data could provide crucial information helping to distinguish scalar-tensor and standard inflationary scenarios.
description: 24 pages, 19 figures, uses RevTex. Qualitative discussions added, matches published version
Pairing effects on the collectivity of quadrupole states around 32Mg
Creators: name: Yamagami, M.
name: Van Giai, Nguyen
Publisher: name: arXiv
Year: 2003
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The first 2+ states in N=20 isotones including neutron-rich nuclei 32Mg and 30Ne are studied by the Hartree-Fock-Bogoliubov plus quasiparticle random phase approximation method based on the Green's function approach. The residual interaction between the quasiparticles is consistently derived from the hamiltonian density of Skyrme interactions with explicit velocity dependence. The B(E2) transition probabilities and the excitation energies of the first 2+ states are well described within a single framework. We conclude that pairing effects account largely for the anomalously large B(E2) value and the very low excitation energy in 32Mg.
description: 14 pages, 9 figures
Domain wall mobility in nanowires: transverse versus vortex walls
Creators: name: Wieser, R.
name: Nowak, U.
name: Usadel, K. D.
Publisher: name: arXiv
Year: 2003
Subjects: subject: Condensed Matter (cond-mat)
subject: FOS: Physical sciences

description: The motion of domain walls in ferromagnetic, cylindrical nanowires is investigated numerically by solving the Landau-Lifshitz-Gilbert equation for a classical spin model in which energy contributions from exchange, crystalline anisotropy, dipole-dipole interaction, and a driving magnetic field are considered. Depending on the diameter, either transverse domain walls or vortex walls are found. The transverse domain wall is observed for diameters smaller than the exchange length of the given material. Here, the system behaves effectively one-dimensional and the domain wall mobility agrees with a result derived for a one-dimensional wall by Slonczewski. For low damping the domain wall mobility decreases with decreasing damping constant. With increasing diameter, a crossover to a vortex wall sets in which enhances the domain wall mobility drastically. For a vortex wall the domain wall mobility is described by the Walker-formula, with a domain wall width depending on the diameter of the wire. The main difference is the dependence on damping: for a vortex wall the domain wall mobility can be drastically increased for small values of the damping constant up to a factor of $1/α^2$.
description: 5 pages, 6 figures
Dynamic Reserve Prices for Repeated Auctions: Learning from Bids
Creators: name: Kanoria, Yash
name: Nazerzadeh, Hamid
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computer Science and Game Theory (cs.GT)
subject: Theoretical Economics (econ.TH)
subject: FOS: Computer and information sciences
subject: FOS: Economics and business

description: A large fraction of online advertisement is sold via repeated second price auctions. In these auctions, the reserve price is the main tool for the auctioneer to boost revenues. In this work, we investigate the following question: Can changing the reserve prices based on the previous bids improve the revenue of the auction, taking into account the long-term incentives and strategic behavior of the bidders? We show that if the distribution of the valuations is known and satisfies the standard regularity assumptions, then the optimal mechanism has a constant reserve. However, when there is uncertainty in the distribution of the valuations, previous bids can be used to learn the distribution of the valuations and to update the reserve price. We present a simple, approximately incentive-compatible, and asymptotically optimal dynamic reserve mechanism that can significantly improve the revenue over the best static reserve. The paper is from July 2014 (our submission to WINE 2014), posted later here on the arxiv to complement the 1-page abstract in the WINE 2014 proceedings.
description: 1-page abstract appeared in the proceedings of Web and Internet Economics ( WINE ), 2014
Comparison of three sources of biodiesel based on a Life Cycle Analysis
Creators: name: Pagès, Benoît
name: Higginson, Anthony
name: Berlemont, Rémi
Publisher: name: The University of British Columbia
Year: 2010

description: Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report.”
General covariance violation and the gravitational dark matter. II. Vector graviton
Creators: name: Pirogov, Yu. F.
Publisher: name: arXiv
Year: 2005
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Astrophysics (astro-ph)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The (four componenet) vector graviton contained in metric, the scalar component incorporated, is attributed to the violation of the general covariance to the residual isoharmonic one. In addition to the previously studied (singlet) scalar graviton, the vector graviton may constitute one more fraction of the gravitational dark matter. The gravity interactions of the vector graviton, as well as its impact on the continuous medium are studied.
description: 10 pages
Constraint and Super Yang-Mills Equations on the Deformed Superspace R^(4|16)_\hbar
Creators: name: Saemann, Christian
name: Wolf, Martin
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: It has been known for quite some time that the N=4 super Yang-Mills equations defined on four-dimensional Euclidean space are equivalent to certain constraint equations on the Euclidean superspace R^(4|16). In this paper we consider the constraint equations on a deformed superspace R^(4|16)_\hbar a la Seiberg and derive the deformed super Yang-Mills equations. In showing this, we propose a super Seiberg-Witten map.
description: v3: harvmac, 1+26 pages, typos fixed, replaced with published version
Nonlocal pseudopotentials and magnetic fields
Creators: name: Pickard, Chris J.
name: Mauri, Francesco
Publisher: name: arXiv
Year: 2003
Subjects: subject: Condensed Matter (cond-mat)
subject: FOS: Physical sciences

description: We show how to describe the coupling of electrons to non-uniform magnetic fields in the framework of the widely used norm-conserving pseudopotential appro ximation for electronic structure calculations. Our derivation applies to magnetic fields that are smooth on the scale of the core region. The method is validated by application to the calculation of the magnetic susceptibility of molecules. Our results are compared with high quality all electron quantum chemical results, and another recently proposed formalism.
description: 4 pages, submitted to Physical Review Letters
Toronto-3D: A Large-scale Mobile LiDAR Dataset for Semantic Segmentation of Urban Roadways
Creators: name: Tan, Weikai
name: Qin, Nannan
name: Ma, Lingfei
name: Li, Ying
name: Du, Jing
name: Cai, Guorong
name: Yang, Ke
name: Li, Jonathan
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Semantic segmentation of large-scale outdoor point clouds is essential for urban scene understanding in various applications, especially autonomous driving and urban high-definition (HD) mapping. With rapid developments of mobile laser scanning (MLS) systems, massive point clouds are available for scene understanding, but publicly accessible large-scale labeled datasets, which are essential for developing learning-based methods, are still limited. This paper introduces Toronto-3D, a large-scale urban outdoor point cloud dataset acquired by a MLS system in Toronto, Canada for semantic segmentation. This dataset covers approximately 1 km of point clouds and consists of about 78.3 million points with 8 labeled object classes. Baseline experiments for semantic segmentation were conducted and the results confirmed the capability of this dataset to train deep learning models effectively. Toronto-3D is released to encourage new research, and the labels will be improved and updated with feedback from the research community.
description: Toronto-3D dataset can be downloaded at https://github.com/WeikaiTan/Toronto-3D
Chromatin and cytoskeletal tethering determine nuclear morphology in progerin expressing cells
Creators: name: Lionetti, M. C.
name: Bonfanti, S.
name: Fumagalli, M. R.
name: Budrikis, Z.
name: Clos, F. Font
name: Costantini, G.
name: Chepizhko, O.
name: Zapperi, S.
name: La Porta, C. A. M.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Cell Behavior (q-bio.CB)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: The nuclear morphology of eukaryotic cells is determined by the interplay between the lamina forming the nuclear skeleton, the chromatin inside the nucleus and the coupling with the cytoskeleton. Nuclear alterations are often associated with pathological conditions as in the Hutchinson-Gilford progeria syndrome (HGPS) where a mutation in the lamin A gene yields an altered form of the protein, named progerin, and an aberrant nuclear shape. Here, we introduce an inducible cellular model of HGPS in HeLa cells where increased progerin expression leads to alterations in the coupling of the lamin shell with cytoskeletal/chromatin tethers as well as with Polycomb-group (PcG) proteins. Furthermore, our experiments show that progerin expression leads to enhanced nuclear shape fluctuations in response to cytoskeletal activity. To interpret the experimental results, we introduce a computational model of the cell nucleus that includes explicitly chromatin fibers, the nuclear shell and the coupling with the cytoskeleton. The model allows us to investigate how the geometrical organization of chromatin-lamin tether affects nuclear morphology and shape fluctuations. In sum, our findings highlight the crucial role played by lamin-chromatin and lamin-cytoskeletal alterations in determining nuclear shape morphology and in affecting cellular functions and gene regulation.
description: 38 pages, 25 figures
Gyrating Strings: A new instability of black strings?
Creators: name: Marolf, Donald
name: Palmer, Belkis Cabrera
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: A thermodynamic argument is presented suggesting that near-extremal spinning D1-D5-P black strings become unstable when their angular momentum exceeds $J_{crit} = {3Q_1Q_5}/2\sqrt{2}$. In contrast, the dimensionally reduced black holes are thermodynamically stable. The proposed instability involves a phase in which the spin angular momentum above $J_{crit}$ is transferred to gyration of the string in space; i.e., to orbital angular momentum of parts of the string about the mean location in space. Thus the string becomes a rotating helical coil. We note that an instability of this form would yield a counter-example to the Gubser-Mitra conjecture, which proposes a particular link between dynamic black string instabilities and the thermodynamics of black strings. There may also be other instabilities associated with radiation modes of various fields. Our arguments also apply to the D-brane bound states associated with these black strings in weakly coupled string theory.
description: 6 pages, revtex4, zero of Hessian noted, references added
Rates, Polarizations, and Asymmetries in Charmless Vector-Vector B Meson Decays
Creators: name: The BABAR Collaboration
name: Aubert, B.
Publisher: name: arXiv
Year: 2003
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: With a sample of approximately 89 million BBbar pairs collected with the BABAR detector, we perform a search for B meson decays into pairs of charmless vector mesons (phi, rho, and K*). We measure the branching fractions, determine the degree of longitudinal polarization, and search for CP violation asymmetries in the processes B->phiK*+, B->phiK*0, B->rho0K*+, and B->rho0rho+. We also set an upper limit on the branching fraction for the decay B->rho0rho0.
description: 7 pages, 2 postscript figures, published in Phys. Rev. Lett
Evidence of itinerant holes for long-range magnetic order in tungsten diselenide semiconductor with vanadium dopants
Creators: name: Song, Bumsub
name: Yun, Seok Joon
name: Jiang, Jinbao
name: Beach, Kory
name: Choi, Wooseon
name: Kim, Young-Min
name: Terrones, Humberto
name: Song, Young Jae
name: Duong, Dinh Loc
name: Lee, Young Hee
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: One primary concern in diluted magnetic semiconductors (DMSs) is how to establish a long-range magnetic order with a low magnetic doping concentration to maintain the gate tunability of the host semiconductor, as well as to increase Curie temperature. Two-dimensional van der Waals semiconductors have been recently investigated to demonstrate the magnetic order in DMSs; however, a comprehensive understanding of the mechanism responsible for the gate-tunable long-range magnetic order in DMSs has not been achieved yet. Here, we introduce a monolayer tungsten diselenide (WSe2) semiconductor with V dopants to demonstrate the long-range magnetic order through itinerant spin-polarized holes. The V atoms are sparsely located in the host lattice by substituting W atoms, which is confirmed by scanning tunneling microscopy and high-resolution transmission electron microscopy. The V impurity states and the valence band edge states are overlapped, which is congruent with density functional theory calculations. The field-effect transistor characteristics reveal the itinerant holes within the hybridized band; this clearly resembles the Zener model. Our study gives an insight into the mechanism of the long-range magnetic order in V-doped WSe2, which can also be used for other magnetically doped semiconducting transition metal dichalcogenides.
description: 19 pages, 4 figures
Chiral Supersymmetric Gepner Model Orientifolds
Creators: name: Blumenhagen, Ralph
name: Weigand, Timo
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We explicitly construct A-type orientifolds of supersymmetric Gepner models. In order to reduce the tadpole cancellation conditions to a treatable number we explicitly work out the generic form of the one-loop Klein bottle, annulus and Moebius strip amplitudes for simple current extensions of Gepner models. Equipped with these formulas, we discuss two examples in detail to provide evidence that in this setting certain features of the MSSM like unitary gauge groups with large enough rank, chirality and family replication can be achieved.
description: 37 pages, TeX (harvmac), minor changes, typos corrected, to appear in JHEP
Implementing Sustainable production techniques and landscape management at the UBC Farm: A Hands-on Approach
Creators: name: McNeill, Gemma
name: Hall, Alicia
name: Dring, Colin
name: Pearson, Kristine
name: Ngai, Adrienne
name: Ng, Ruth
name: Ninkovic, Anja
name: Ngan, Jenifer
Publisher: name: The University of British Columbia
Year: 2010

description: Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report.”
The Study of the Continuum Limit of the Supersymmetric Ward-Takahashi Identity for N=1 Super Yang-Mills Theory
Creators: name: Feo, A.
Publisher: name: arXiv
Year: 2003
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The one-loop corrections to the supersymmetric Ward-Takahashi identity (WTi) are investigated in the off-shell regime in the Wilson formulation of the discretized N=1 Super Yang-Mills (SYM) theory. The study of the continuum limit as well as the renormalization procedure for the supercurrent are presented.
description: Talk at Confinement 2003
Hodge decomposition of string topology
Creators: name: Berest, Yuri
name: Ramadoss, Ajay C.
name: Zhang, Yining
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Algebra (math.QA)
subject: Algebraic Topology (math.AT)
subject: Rings and Algebras (math.RA)
subject: FOS: Mathematics

description: Let $X$ be a simply connected closed oriented manifold of rationally elliptic homotopy type. We prove that the string topology bracket on the $S^1$-equivariant homology $\overline{H}_{\ast}^{S^1}(\mathcal{L}X,\mathbb{Q}) $ of the free loop space of $X$ preserves the Hodge decomposition of $\overline{H}_{\ast}^{S^1}(\mathcal{L}X,\mathbb{Q}) $ , making it a bigraded Lie algebra. We deduce this result from a general theorem on derived Poisson structures on the universal enveloping algebras of homologically nilpotent finite-dimensional DG Lie algebras. Our theorem settles a conjecture proposed in our earlier work.
description: 28 pages
Lost equivalence of nonlinear sigma and $CP^{1}$ models on noncommutative space
Creators: name: Otsu, H.
name: Sato, T.
name: Ikemori, H.
name: Kitakado, S.
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We show that the equivalence of nonlinear sigma and $CP^{1}$ models which is valid on the commutative space is broken on the noncommutative space. This conclusion is arrived at through investigation of new BPS solitons that do not exist in the commutative limit.
description: 17 pages, LaTeX2e
Stabilities of Shape Identification Inverse Problems in a Bayesian Framework
Creators: name: Kawakami, Hajime
Publisher: name: arXiv
Year: 2020
Subjects: subject: Statistics Theory (math.ST)
subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35K05, 35K10, 35R30, 60J60, 62F15

description: A general shape identification inverse problem is studied in a Bayesian framework. This problem requires the determination of the unknown shape of a domain in the Euclidean space from finite-dimensional observation data with some Gaussian random noise. Then, the stability of posterior is studied for observation data. For each point of the space, the conditional probability that the point is included in the unknown domain given the observation data is considered. The stability is also studied for this probability distribution. As a model problem for our inverse problem, a heat inverse problem is considered. This problem requires the determination of the unknown shape of cavities in a heat conductor from temperature data of some portion of the surface of the heat conductor. To apply the above stability results to this model problem, one needs the measurability and some boundedness of the forward operator. These properties are shown.
description: Accepted by Journal of Mathematical Analysis and Applications
Measuring Hidden Bias within Face Recognition via Racial Phenotypes [other]
Creators: name: Yucer, Seyma
Publisher: name: Durham University
Year: 2021
Subjects: subject: Face perception--Racial bias
subject: Facial phenotypes
subject: Labels
subject: Pre-trained models

description: Deposit consists of metadata files of two datasets and one machine learning model trained parameters. Code published on GitHub: https://github.com/seymayucer/FacialPhenotypes
description: Originally published as: Understanding racial bias using facial phenotypes
description: Recent work reports disparate performance for intersectional racial groups across face recognition tasks: face verification and identification. However, the definition of those racial groups has a significant impact on the underlying findings of such racial bias analysis. Previous studies define these groups based on either demographic information (e.g. African, Asian etc.) or skin tone (e.g. lighter or darker skins). The use of such sensitive or broad group definitions has disadvantages for bias investigation and subsequent counter-bias solutions design. By contrast, this study introduces an alternative racial bias analysis methodology via facial phenotype attributes for face recognition. We use the set of observable characteristics of an individual face where a race-related facial phenotype is hence specific to the human face and correlated to the racial profile of the subject. We propose categorical test cases to investigate the individual influence of those attributes on bias within face recognition tasks. We compare our phenotype-based grouping methodology with previous grouping strategies and show that phenotype-based groupings uncover hidden bias without reliance upon any potentially protected attributes or ill-defined grouping strategies. Furthermore, we contribute corresponding phenotype attribute category labels for two face recognition tasks: RFW for face verification and VGGFace2 (test set) for face identification.