cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Microwave Lens for Polar Molecules
Creators: name: Odashima, Hitoshi
name: Merz, Simon
name: Enomoto, Katsunari
name: Schnell, Melanie
name: Meijer, Gerard
Publisher: name: arXiv
Year: 2010
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: We here report on the implementation of a microwave lens for neutral polar molecules suitable to focus molecules both in low-field-seeking and in high-field-seeking states. By using the TE_11m modes of a 12 cm long cylindrically symmetric microwave resonator, Stark-decelerated ammonia molecules are transversally confined. We investigate the focusing properties of this microwave lens as a function of the molecules' velocity, the detuning of the microwave frequency from the molecular resonance frequency, and the microwave power. Such a microwave lens can be seen as a first important step towards further microwave devices, such as decelerators and traps.
description: 4 pages, 3 figures
On the lack of stellar bars in Coma dwarf galaxies
Creators: name: Mendez-Abreu, J.
name: Sanchez-Janssen, R.
name: Aguerri, J. A. L.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We present a study of the bar fraction in the Coma cluster galaxies based on a sample of ~190 galaxies selected from the SDSS-DR6 and observed with the Hubble Space Telescope (HST) Advanced Camera for Survey (ACS). The unprecedented resolution of the HST-ACS images allows us to explore the presence of bars, detected by visual classification, throughout a luminosity range of 9 mag (-23 < M_r < -14), permitting us to study the poor known region of dwarf galaxies. We find that bars are hosted by galaxies in a tight range of both luminosities (-22 < M_r < -17) and masses (10^9 < M*/Msun < 10^11). In addition, we find that the bar fraction does not vary significantly when going from the center to the cluster outskirts, implying that cluster environment plays a second-order role in bar formation/evolution. The shape of the bar fraction distribution with respect to both luminosity and mass is well matched by the luminosity distribution of disk galaxies in Coma, indicating that bars are good tracers of cold stellar disks.
description: 2 pages, 1 figure, to appear in the proceedings of the conference "A Universe of Dwarf Galaxies" (Lyon, June 14-18, 2010)
Excitonic Tunneling in the AB-bilayer Graphene Josephson Junctions
Creators: name: Apinyan, V.
name: Kopeć, T. K.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We have considered the AB-stacked bilayer graphene Josephson junction. The bilayers are supposed to be in the charge equilibrium states and at the half-filling in each of the electronic layers of the construction and at each value of the external gate. By considering the interacting bilayers in both sides of the junction and by taking into account both intralayer and interlayer Coulomb interaction effects, we have calculated the normal and excitonic tunnel currents through the junction. The electronic band renormalizations have been taken into account, due to the excitonic pairing effects and condensation in the BLGs. The exact four-band energy dispersions, including the excitonic renormalizations, have been used for the bilayers without any low-energy approximation. We show the degeneracy of the ground state at the zero applied voltage and for different phases of the coherent condensates by showing a dc Josephson current through the junction. The normal and excitonic tunneling currents have been calculated for different gate voltages and for different values of the interaction parameters. The role of the charge neutrality point has been discussed in details.
description: 17 pages, 14 Figures
Electronic charges and electric potential at LaAlO3/SrTiO3 interfaces studied by core-level photoemission spectroscopy
Creators: name: Takizawa, M.
name: Tsuda, S.
name: Susaki, T.
name: Hwang, H. Y.
name: Fujimori, A.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We studied LaAlO3/SrTiO3 interfaces for varying LaAlO3 thickness by core-level photoemission spectroscopy. In Ti 2p spectra for conducting "n-type" interfaces, Ti3+ signals appeared, which were absent for insulating "p-type" interfaces. The Ti3+ signals increased with LaAlO3 thickness, but started well below the critical thickness of 4 unit cells for metallic transport. Core-level shifts with LaAlO3 thickness were much smaller than predicted by the polar catastrophe model. We attribute these observations to surface defects/adsorbates providing charges to the interface even below the critical thickness.
Threshold concepts in the Scholarship of Teaching and Learning : a phenomenological study of educational leaders in a Canadian research-intensive university
Creators: name: Webb, Andrea Suzanne
Publisher: name: University of British Columbia
Year: 2015

description: This research study explored the lived experience of educational leaders in a research-intensive context as they engage in the Scholarship of Teaching and Learning (SoTL) in the University of British Columbia’s Faculty Scholarship of Teaching and Learning Leadership Program (UBC SoTL Leadership Program). The study was guided by two research questions: (1) What is the nature and substance of threshold concepts in SoTL and (2) What enhances or constrains educational leaders’ ability to navigate threshold concepts in SoTL? A qualitative phenomenological inquiry approach was employed over a nine-month period to explore educational leaders’ experience with SoTL. Data collection and analysis were informed by van Manen’s interpretive phenomenology and data sources included a questionnaire, participant observation in classroom sessions, interviews with members of the 2013-2014 cohort and past graduates of the program, and participants’ ePortfolios. The research questions sought to explore threshold concepts in SoTL as well as factors that enhance or constrain the ability of institution-level and Faculty-level educational leaders to navigate threshold concepts in the scholarship of teaching and learning in a research-intensive university. Seven themes emerged from the analysis as potential SoTL threshold concepts for the participants: conceptions of research, subjectivity, institutional culture, studentness, boundary crossing, teaching as scholarship, and the disposition of a SoTL scholar. The concepts were examined in light of four defining characteristics of threshold concepts. The first five of the themes exhibited significant evidence of the characteristics and were categorized as threshold concepts. The final two themes exhibited some of the characteristics and warrant further inquiry. Further data analysis indicated that educational leaders’ ability to navigate threshold concepts was enhanced and constrained by their understanding of the nature of SoTL and disciplinary and institutional cultures in which they undertake their daily work. These results offer important insights for understanding how threshold concepts are manifest in a SoTL based faculty development program for institution-level and Faculty-level UBC SoTL Leadership Program educational leaders and insights into how these concepts might have been navigated in such contexts.
Inventário de referências a livros litúrgicos na documentação asturiano-leonesa relativa ao Entre-Minho-e-Mondego (séc. IX-XI)
Creators: name: Gouveia, Mário De
Publisher: name: Lusitania Sacra
Year: 2015

description: Apresenta-se neste artigo um inventário de referências a livros litúrgicos constantes da documentação relativa ao Entre-Minho-e-Mondego entre os séculos IX e XI. Pretende-se com a sua publicação colocar à disposição dos investigadores um instrumento de trabalho que se possa entender como um ponto de partida para a elaboração de estudos sectoriais sobre a circulação de livros litúrgicos nas igrejas e mosteiros de uma região periférica do reino de Astúrias-Leão durante a Alta Idade Média.
description: Lusitania Sacra, n. 31 (2015): Vivências Religiosas Femininas Medievais
Excitation of the isomeric ^{229m}Th nuclear state via an electronic bridge process in ^{229}Th^+
Creators: name: Porsev, S. G.
name: Flambaum, V. V.
name: Peik, E.
name: Tamm, Chr.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We consider the excitation of the nuclear transition ^{229g}Th - ^{229m}Th near 7.6 eV in singly ionized thorium via an electronic bridge process. The process relies on the excitation of the electron shell by two laser photons whose sum frequency is equal to the nuclear transition frequency. This scheme allows to determine the nuclear transition frequency with high accuracy. Based on calculations of the electronic level structure of Th^+ which combine the configuration-interaction method and many-body perturbation theory, we estimate that a nuclear excitation rate in the range of 10 s^{-1} can be obtained using conventional laser sources.
description: 4 pages, 3 figures
Uma Inquisição diferente: para uma leitura institucional do Santo Ofício de Goa e do seu distrito (séculos XVI e XVII)
Creators: name: Lourenço, Miguel Rodrigues
Publisher: name: Lusitania Sacra
Year: 2015

description: A circunstância de, em Goa, se ter constituído a única sede extra-peninsular de um tribunal do Santo Ofício nos domínios da Coroa de Portugal conferiu à “Inquisição da Índia” uma singularidade no contexto dos distritos inquisitoriais portugueses. Contudo, se o seu carácter não peninsular evidencia, no imediato, uma originalidade do tribunal com base num critério espacial, importa aferir em que medida é que esta variável afetou, na prática, os procedimentos institucionais mantidos em Goa. Neste estudo, procuraremos objetivar a especificidade da Inquisição de Goa a partir de uma caracterização geográfica e social do distrito que tutela.
description: Lusitania Sacra, n. 31 (2015): Vivências Religiosas Femininas Medievais
Creada a su imagen y semajanza: la coronación de la Reina de Aragón según las Ordenaciones de Pedro el Ceremonioso
Creators: name: Silleras-Fernández, Núria
Publisher: name: Lusitania Sacra
Year: 2015

description: En 1353 Pedro el Ceremonioso (n. 1319, r. 1336-87) promulgó una ordenación que reglamentaba la coronación del rey y la reina de la Corona de Aragón. El presente artículo analiza detalladamente el texto de coronación de la reina entendido en sentido metafórico, porque se identifica algo real, la reina, con algo imaginario o evocado, la figura de la reina según las ordenaciones. El examen de la relación y de las similitudes entre ambas imágenes permite vislumbrar el complejo papel desempeñado por la reina de Aragón, en la teoría y en la práctica.
description: Lusitania Sacra, n. 31 (2015): Vivências Religiosas Femininas Medievais
Evaluation of image-shift measurement algorithms for solar Shack-Hartmann wavefront sensors
Creators: name: Löfdahl, Mats G.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: Context. Solar Shack-Hartmann wavefront sensors measure differential wavefront tilts as the relative shift between images from different subapertures. There are several methods in use for measuring these shifts. Aims. We evaluate the inherent accuracy of the methods and the effects of various sources of error, such as noise, bias mismatch, and blurring. We investigate whether Z-tilts or G-tilts are measured. Methods. We test the algorithms on two kinds of artificial data sets, one corresponding to images with known shifts and one corresponding to seeing with different r_0. Results. Our results show that the best methods for shift measurements are based on the square difference function and the absolute difference function squared, with subpixel accuracy accomplished by use of two-dimensional quadratic interpolation. These methods measure Z-tilts rather than G-tilts.
description: In press in Astronomy & Astrophysics. 19 pages, 10 figures, 10 tables
Magnetic Energy Buildup for Relativistic Magnetar Giant Flares
Creators: name: Yu, Cong
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Motivated by coronal mass ejection studies, we construct general relativistic models of a magnetar magnetosphere endowed with strong magnetic fields. The equilibrium states of the stationary, axisymmetric magnetic fields in the magnetar magnetosphere are obtained as solutions of the Grad-Shafranov equation in a Schwarzschild spacetime. To understand the magnetic energy buildup in the magnetar magnetosphere, a generalized magnetic virial theorem in the Schwarzschild metric is newly derived. We carefully address the question whether the magnetar magnetospheric magnetic field can build up sufficient magnetic energy to account for the work required to open up the magnetic field during magnetar giant flares. We point out the importance of the Aly-Sturrock constraint, which has been widely studied in solar corona mass ejections, as a reference state in understanding magnetar energy storage processes. We examine how the magnetic field can possess enough energy to overcome the Aly-Sturrock energy constraint and open up. In particular, general relativistic (GR) effects on the Aly-Sturrock energy constraint in the Schwarzschild spacetime are carefully investigated. It is found that, for magnetar outbursts, the Aly-Sturrock constraint is more stringent, i.e., the Aly-Sturrock energy threshold is enhanced due to the GR effects. In addition, neutron stars with greater mass have a higher Aly-Sturrock energy threshold and are more difficult to erupt. This indicates that magnetars are probably not neutron stars with extreme mass. For a typical neutron star with mass of $1-2 M_{\odot}$, we further explore the effects of cross-field current effects, caused by the mass loading, on the possibility of stored magnetic field energy exceeding the Aly-Sturrock threshold.
description: Accepted for publication in Astrophysical Journal
The gauge-string duality and heavy ion collisions
Creators: name: Gubser, Steven S.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: History and Philosophy of Physics (physics.hist-ph)
subject: FOS: Physical sciences

description: I review at a non-technical level the use of the gauge-string duality to study aspects of heavy ion collisions, with special emphasis on the trailing string calculation of heavy quark energy loss. I include some brief speculations on how variants of the trailing string construction could provide a toy model of black hole formation and evaporation. This essay is an invited contribution to "Forty Years of String Theory" and is aimed at philosophers and historians of science as well as physicists.
description: 21 pages
On the use of electron-multiplying CCDs for astronomical spectroscopy
Creators: name: Tulloch, Simon
name: Dhillon, Vik
Publisher: name: arXiv
Year: 2010
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences
subject: 85-02

description: Conventional CCD detectors have two major disadvantages: they are slow to read out and they suffer from read noise. These problems combine to make high-speed spectroscopy of faint targets the most demanding of astronomical observations. It is possible to overcome these weaknesses by using electron-multiplying CCDs (EMCCDs). EMCCDs are conventional frame-transfer CCDs, but with an extended serial register containing high-voltage electrodes. An avalanche of secondary electrons is produced as the photon-generated electrons are clocked through this register, resulting in signal amplification that renders the read noise negligible. Using a combination of laboratory measurements with the QUCAM2 EMCCD camera and Monte Carlo modelling, we show that it is possible to significantly increase the signal-to-noise ratio of an observation by using an EMCCD, but only if it is optimised and utilised correctly. We also show that even greater gains are possible through the use of photon counting. We present a recipe for astronomers to follow when setting up a typical EMCCD observation which ensures that maximum signal-to-noise ratio is obtained. We also discuss the benefits that EMCCDs would bring if used with the next generation of extremely large telescopes. Although we mainly consider the spectroscopic use of EMCCDs, our conclusions are equally applicable to imaging.
description: 18 figures, 3 tables, 18 pages
Decision analysis models for aircraft engine maintenance planning using discrete event simulation
Creators: name: Razavi, Behnam
Publisher: name: University of British Columbia
Year: 2015

description: With stringent standards for materials, manufacturing, operation, and quality control, jet engines in use on commercial aircraft are very reliable. It is not uncommon for engines to operate for thousands of hours before being scheduled for inspection, service or repair. However, due to required maintenance and unexpected failures aircraft must be periodically grounded and their engines attended to. The tasks of maintenance and repair without optimal planning can be costly and result in prolonged maintenance times, reduced availability and possible flight delays. These factors have a negative impact on both the airline operators and the passengers alike. Aircraft manufacturers and maintainers, who provide after sale services, see significant benefits in constantly improving health management and maintenance practices by deploying the most effective maintenance strategies. Maintenance is seen as an imposed cost that ought to be minimized. Airlines must evaluate new technologies and their possible role in reducing the long term expenditure for operating a fleet of aircraft throughout its life cycle. A significant share of these expenses goes towards maintenance of these aircraft, especially their engines. This study presents a model-based integrated decision making system for aircraft engine maintenance planning. The goal is to determine the optimum number of engines on an aircraft for maintenance based on logged engine operation data in order to maximize the use of estimated remaining time to the next service as well as to minimize the duration of downtime. To achieve this, engine condition is used in a set of preliminary Discrete Event Simulation (DES) models to evaluate and provide the most effective maintenance policies for the aircraft engines. To assess options for making decisions, a comprehensive model is developed based on the integration of the smaller preliminary maintenance models for one, two, three and four engine maintenance cases. Results from these analyses determine the optimal number of engines tagged for maintenance on any aircraft in the fleet that arrives at the service facility. Since the materials, technicians and other costs are proprietary information, this study is time-based but allowance is made for the user to include associated costs and thus perform cost-based decision making.
An Effective Field Theory Look at Deep Inelastic Scattering
Creators: name: Paz, Gil
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: This talk discusses the effective field theory view of deep inelastic scattering. In such an approach, the standard factorization formula of a hard coefficient multiplied by a parton distribution function arises from matching of QCD onto an effective field theory. The DGLAP equations can then be viewed as the standard renormalization group equations that determines the cut-off dependence of the non-local operator whose forward matrix element is the parton distribution function. As an example, the non-singlet quark splitting functions is derived directly from the renormalization properties of the non-local operator itself. This approach, although discussed in the literature, does not appear to be well known to the larger high energy community. In this talk we give a pedagogical introduction to this subject.
description: 11 pages, 1 figure, To appear in Modern Physics Letters A
Fundaciones conventuales femeninas y Querella de las Mujeres en la ciudad del siglo XV
Creators: name: Cid, María Del Mar Graña
Publisher: name: Lusitania Sacra
Year: 2015

description: El siglo XV asistió en la Corona de Castilla a un amplio y diversificado fenómeno de creaciones conventuales femeninas promovidas por mujeres que fue muy visible en las ciudades. Se inscribió en las reformas de la Baja Edad Media y coincidió con el debate conocido como “Querella de las Mujeres”. Partiendo de la idea de que hubo un Humanismo femenino, pensado y enunciado por las mujeres en sus propios términos, en estas páginas se buscan las conexiones entre dichos fenómenos, especialmente entre las aportaciones femeninas de reforma religiosa concretadas en las fundaciones de espacios de espiritualidad y la “Querella de las Mujeres”. Para ello, se fundamenta el análisis en una ciudad concreta, Córdoba, y se delimitan cronologías y tipologías religiosas a fin de determinar sus contenidos programáticos. El objetivo último es perfilar algunas de las principales formulaciones y claves explicativas del proyecto humanista de las mujeres.
description: Lusitania Sacra, n. 31 (2015): Vivências Religiosas Femininas Medievais
Generalized Geologic Map for Land-Use Planning: McCreary County, Kentucky
Creators: name: Carey, Daniel I.
name: Paylor, Randall L.
name: Overfield, Bethany L.
Publisher: name: Kentucky Geological Survey, University of Kentucky
Year: 2006

description: Abstract:
This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.
Em torno de uma experiência religiosa feminina: as mulheres da "pobre vida" de Évora
Creators: name: Fontes, João Luís Inglês
Publisher: name: Lusitania Sacra
Year: 2015

description: Tomando como campo de observação a cidade de Évora, o presente artigo procura analisar o percurso das várias experiências religiosas não regulares protagonizadas por mulheres, no interior da urbe, ao longo do século XV. O registo, nos livros de aniversários da Sé de Évora, de várias mulheres pobres ou reclusas que aí se fizeram sepultar e confiaram aos seus clérigos a intercessão pelas suas almas, é o pretexto para analisar a forte implementação, na cidade, destes grupos femininos adeptos da pobre vida, a sua evolução ao longo da centúria e a inflexão, em finais da centúria, conducente à sua gradual institucionalização e conversão em comunidades monásticas regulares. O protagonismo feminino assumido no apoio ou na adesão a estes grupos cruza-se com as dinâmicas de crescimento e de enquadramento destas opções religiosas não institucionalizadas que constituem, por si, um espaço de autonomia e de afirmação, social e religiosa, das mulheres no âmbito do mundo medieval.
description: Lusitania Sacra, n. 31 (2015): Vivências Religiosas Femininas Medievais
Mulheres sob custódia: as comunidades de clarissas como espaços de obediência e autonomia (séculos XIII e XIV)
Creators: name: Andrade, Maria Filomena
Publisher: name: Lusitania Sacra
Year: 2015

description: A Ordem de Santa Clara teve um papel fundamental na vivência da espiritualidade feminina na Idade Média em Portugal. Aos conventos de clarissas chegavam mulheres de todos os estratos sociais revelando a vitalidade da mensagem de Francisco e de Clara. Sujeitas ao voto de clausura e tuteladas pelos Franciscanos, estas comunidades parecem “encerrar” mulheres submetidas e vigiadas pelo poder masculino. Como se relacionam estas mulheres com o mundo masculino que as tutela e que com elas interage? E, estando sujeitas à clausura, como é que estas comunidades estabelecem relações com o mundo que as rodeia? De monjas tuteladas e vigiadas, as clarissas passam a tomar um papel de protagonistas da sua história, construindo comunidades vivas e atuantes, onde as mulheres assumem os seus papéis de liderança e concitam dos homens uma atitude de interajuda e de solidariedade de forma a viverem de forma autónoma mas em constante relação com o mundo exterior.
description: Lusitania Sacra, n. 31 (2015): Vivências Religiosas Femininas Medievais
Broadening the applicability of FPGA-based soft vector processors
Creators: name: Severance, Aaron
Publisher: name: University of British Columbia
Year: 2015

description: A soft vector processor (SVP) is an overlay on top of FPGAs that allows data- parallel algorithms to be written in software rather than hardware, and yet still achieve hardware-like performance. This ease of use comes at an area and speed penalty, however. Also, since the internal design of SVPs are based largely on custom CMOS vector processors, there is additional opportunity for FPGA-specific optimizations and enhancements. This thesis investigates and measures the effects of FPGA-specific changes to SVPs that improve performance, reduce area, and improve ease-of-use; thereby expanding their useful range of applications. First, we address applications needing only moderate performance such as audio filtering where SVPs need only a small number (one to four) of parallel ALUs. We make implementation and ISA design decisions around the goals of producing a compact SVP that effectively utilizes existing BRAMs and DSP Blocks. The resulting VENICE SVP has 2x better performance per logic block than previous designs. Next, we address performance issues with algorithms where some vector elements ‘exit early’ while others need additional processing. Simple vector predication causes all elements to exhibit ‘worst case’ performance. Density time masking (DTM) improves performance of such algorithms by skipping the completed elements when possible, but traditional implementations of DTM are coarse-grained and do not map well to the FPGA fabric. We introduce a BRAM-based implementation that achieves 3.2x higher performance over the base SVP with less than 5% area overhead. Finally, we identify a way to exploit the raw performance of the underlying FPGA fabric by attaching wide, deeply pipelined computational units to SVPs through a custom instruction interface. We support multiple inputs and outputs, arbitrary-length pipelines, and heterogeneous lanes to allow streaming of data through large operator graphs. As an example, on an n-body simulation problem, we show that custom instructions achieve 120x better performance per area than the base SVP.
On the connectivity of visibility graphs
Creators: name: Payne, Michael S.
name: Pór, Attila
name: Valtr, Pavel
name: Wood, David R.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 52C10, 05C40, 05C10, 05C12, 05C62

description: The visibility graph of a finite set of points in the plane has the points as vertices and an edge between two vertices if the line segment between them contains no other points. This paper establishes bounds on the edge- and vertex-connectivity of visibility graphs. Unless all its vertices are collinear, a visibility graph has diameter at most 2, and so it follows by a result of Plesník (1975) that its edge-connectivity equals its minimum degree. We strengthen the result of Plesník by showing that for any two vertices v and w in a graph of diameter 2, if deg(v) <= deg(w) then there exist deg(v) edge-disjoint vw-paths of length at most 4. Furthermore, we find that in visibility graphs every minimum edge cut is the set of edges incident to a vertex of minimum degree. For vertex-connectivity, we prove that every visibility graph with n vertices and at most l collinear vertices has connectivity at least (n-1)/(l-1), which is tight. We also prove the qualitatively stronger result that the vertex-connectivity is at least half the minimum degree. Finally, in the case that l=4 we improve this bound to two thirds of the minimum degree.
description: 16 pages, 8 figures
María de Cervelló: el velo hagiográfico y la piedad no reglada en la Barcelona del siglo XIII
Creators: name: Garí, Blanca
Publisher: name: Lusitania Sacra
Year: 2015

description: Este artículo restaura en primer lugar el proceso de construcción hagiográfica de la figura de Maria de Cervelló. Se analizan en él el peso de las primeras vidas medievales, cuyo original no conservamos, pasando por las copias del siglo XV destinadas a su oficialización en el Capítulo General de la Orden de 1442, y las copias realizadas en el contexto del proceso de canonización del s.XVII. Partiendo del reconocimiento de una progresiva manipulación de la figura de Maria y de las fuentes que nos hablan de ella, el artículo se interroga sobre las posibilidades que nos ofrecen estas fuentes para lograr conocer algo acerca de la existencia en la Barcelona del siglo XIII de una comunidad de beguinas cercanas a la espiritualidad mercedaria. A pesar de los muchos problemas que las hagiografías plantean la autora considera que es posible “des-velar” las fuentes e intuir lo que había detrás de ellas.
description: Lusitania Sacra, n. 31 (2015): Vivências Religiosas Femininas Medievais
On conformal Killing symmetric tensor fields on Riemannian manifolds
Creators: name: Dairbekov, Nurlan S.
name: Sharafutdinov, Vladimir A.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 53A45 (Primary) 53B20 (Secondary)

description: A vector field on a Riemannian manifold is called conformal Killing if it generates one-parameter group of conformal transformations. The class of conformal Killing symmetric tensor fields of an arbitrary rank is a natural generalization of the class of conformal Killing vector fields, and appears in different geometric and physical problems. A symmetric tensor field is a trace-free field if the contraction of the field with the metric tensor is identically equal to zero. On a Riemannian manifold of dimension at least three, the space of trace-free conformal Killing symmetric tensor fields of arbitrary rank is of a finite dimension. On a two-dimensional manifold, the space can be of infinite dimension. Nevertheless, on a connected manifold of any dimension, a trace-free conformal Killing tensor field is uniquely determined by its $C^\infty$-jet at any point. We prove the statement: On a connected manifold, a trace-free conformal Killing tensor field is identically equal to zero if it vanishes on some hypersurface. This statement is a basis of the theorem on decomposition of a symmetric tensor field on a compact Riemannian manifold with boundary to a sum of three fields such that the first summand is a trace-free and divergence-free field, the second summand is a potential field with a trace-free potential vanishing on the boundary, and the last summand is a multiple of the metric tensor. The classical theorem by Bochner - Yano states the absence of conformal Killing vector fields on a closed manifold of negative Ricci curvature. We generalize the latter statements to arbitrary rank tensor fields but under the stronger hypothesis: the sectional curvature is assumed to be negative. There is no nontrivial trace-free conformal Killing symmetric tensor field of any rank on a closed negatively curved Riemannian manifold.
description: 44 pages
An explicit model for the adiabatic evolution of quantum observables driven by 1D shape resonances
Creators: name: Faraj, A.
name: Mantile, A.
name: Nier, F.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mathematical Physics (math-ph)
subject: Analysis of PDEs (math.AP)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 35J10, 35B34, 47A20, 81Q12

description: This paper is concerned with a linearized version of the transport problem where the Schrödinger-Poisson operator is replaced by a non-autonomous Hamiltonian, slowly varying in time. We consider an explicitly solvable model where a semiclassical island is described by a flat potential barrier, while a time dependent 'delta' interaction is used as a model for a single quantum well. Introducing, in addition to the complex deformation, a further modification formed by artificial interface conditions, we give a reduced equation for the adiabatic evolution of the sheet density of charges accumulating around the interaction point.
description: latex; 26 pages
Are Farmers Losing Their Right to Manage Their Farms Because of Contract Farming?
Creators: name: Scoville, Orlin J.
Publisher: name: Unknown
Year: 1958
Subjects: subject: Agribusiness
subject: Farm Management
subject: Marketing
subject: FOS: Economics and business
subject: Research and Development/Tech Change/Emerging Technologies

description: Excerpt: Farmers should be concerned about keeping the essential rights to the management of their farms in their own hands either as individuals or through cooperatives, or both. Farmers make up only about a third to a fourth of all the people who work to produce, process, and market farm products, including those who produce farm supplies. If large numbers of farmers should cease to assert major responsibilities for farm management and the risks of production, they might become submerged in the larger total of what has been called the "agribusiness sector." If the people who live out on the farms cease to make the vital decisions, they will become in effect piece workers, sharecroppers, or wage hands, and other entrepreneurs that have assumed the risks and responsibilities of management will eventually become the leaders of, and the spokesmen for, agriculture.
description: Delivered at the Second Farm Management Short Course, Farm and Home Week, Clemson Agricultural College, August 12, 1958.
Two-bands superconductivity with intra- and interband pairing for synthetic superlattices
Creators: name: Schmidt, Alex A.
name: Rodríguez-Núñez, Jose J.
name: Bianconi, Antonio
name: Perali, Andrea
Publisher: name: arXiv
Year: 2010
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We consider a model for superconductivity in a two-band superconductor, having an anisotropic electronic structure made of two partially overlapping bands with a first hole-like and a second electron-like fermi surface. In this pairing scenario, driven by the interplay between interband $V_{i,j}$ and intraband $V_{i,i}$ pairing terms, we have solved the two gap equations at the critical temperature $T = T_c$ and calculate $T_c$ and the chemical potential $μ$ as a function of the number of carriers $n$ for various values of pairing interactions, $V_{1,1}$, $V_{2,2}$, and $V_{1,2}$. The results show the complexity of the physics of condensates with multiple order parameters with the chemical potential near band edges.
description: 6 pages, 2 figures
Design and characterization of polymeric strain gauges for biomedical applications
Creators: name: Almarghalani, Maan
Publisher: name: University of British Columbia
Year: 2015

description: The market need for organic materials to be used in sensor design has increased with the growing interest in organic printed electronics. Therefore, it is important to find and investigate the piezoelectric and piezoresistive properties of organic materials through the use of alternative rapid fabrication techniques. Poly(3,4- ethylenedioxythiophene) poly(styrenesulfonate), commonly known as PEDOT:PSS, a conductive polymer widely used in organic electronics, can be possibly used as piezoresistive element to measure the strain on flexible substrate electronics. Using PEDOT:PSS and other metallic inks such as silver, the goal of this work is use alternative microfabrication technologies to deposit PEDOT:PSS on flexible substrates and then to use these methods to design strain gauges. The targeted biomedical applications of the designed strain gauges vary from rehabilitation devices to smart biomedical monitoring systems. In this work, PEDOT:PSS strain gauges are initially designed using aerosol jet deposition on a flexible polyamide substrate. The technology has proved to be very powerful in depositing lines with thickness less than 1um. In order to reduce the initial resistance of the strain gauges, it is desirable to increase the thickness of the structure. For this reason, laser micromachining etching is used to fabricate PEDOT:PSS strain gauges. The designed structures have been tested mechanically and electrically in order to measure their gauge factors to longitudinal and transversal mechanical strains. The resultant longitudinal gauge factor varied in the range of -1 and 2, while little change in the resistance was noticed for transversal characterization. Using the same fabrication method, silver paint strain gauges are designed and characterized to have a high longitudinal gauge factor approximated to be higher than 10. The silver paint gauge factor barely responded to transversal actuation. While the variability of the PEDOT:PSS strain gauges results seemed to be an issue, the reproducibility of silver ink strain gauges proved the viability of the technological fabrication process presented in this work.
The geometry of Hrushovski constructions, I. The uncollapsed case
Creators: name: Evans, David M.
name: Ferreira, Marco S.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Logic (math.LO)
subject: FOS: Mathematics
subject: 03C45, 03C30, 03C13

description: An intermediate stage in Hrushovski's construction of flat strongly minimal structures in a relational language L produces omega-stable structures of rank omega. We analyze the pregeometries given by forking on the regular type of rank omega in these structures. We show that varying L can affect the (local) isomorphism type of the pregeometry, but not its finite subpregeometries. A sequel will compare these to the pregeometries of the strongly minimal structures.
description: 31 pages
Dark haloes as seen with gravitational lensing
Creators: name: Kuijken, Konrad
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Dark matter is an important ingredient of galaxies, as was recognised early on by Ken Freeman himself! Evidence for dark matter halos is still indirect, based on analysing motions of tracers such as gas and stars. In a sense the visible galaxy is the mask through which we can study the dark matter. Light rays are also sensitive to gravitational fields, and dark haloes cause observable gravitational lensing effects. There are three regimes: microlensing (which probes the clumpiness of dark matter haloes), strong lensing (sensitive to the inner mass distribution) and weak lensing (which can probe haloes out to 100s of kpc from the center). This review will concentrate on weak lensing, and describe a new survey, the Kilo-Degree Survey (KiDS) that is designed to study galaxy halo masses, extents and shapes as a function of environment, galaxy type and redshift.
description: To appear in 'Galaxies and their Masks' (Namibia, April 2010), eds. Block, D.L., Freeman, K.C. & Puerari, I., 2010, Springer (New York)
Neural Network Prediction of solar cycle 24
Creators: name: Ajabshirizadeh, A.
name: Jouzdani, N. Masoumzadeh
name: Abbassi, S.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The ability to predict the future behavior of solar activity has become of extreme importance due to its effect on the near Earth environment. Predictions of both the amplitude and timing of the next solar cycle will assist in estimating the various consequences of Space Weather. The level of solar activity is usually expressed by international sunspot number ($R_z$). Several prediction techniques have been applied and have achieved varying degrees of success in the domain of solar activity prediction. In this paper, we predict a solar index ($R_z$) in solar cycle 24 by using the neural network method. The neural network technique is used to analyze the time series of solar activity. According to our predictions of yearly sunspot number, the maximum of cycle 24 will occur in the year 2013 and will have an annual mean sunspot number of 65. Finally, we discuss our results in order to compare it with other suggested predictions.
description: Accepted for publication RAA
ILLANES, José Luis (coord.) – Diccionario de San Josemaría Escrivá de Balaguer. Burgos: Editorial Monte Carmelo; Instituto Histórico San Josemaría Escrivá de Balaguer, 2013. 1360 p. ISBN 978-84-8353-592-9
Creators: name: Romo, Eduardo Javier Alonso
Publisher: name: Lusitania Sacra
Year: 2014

description: Lusitania Sacra, n. 30 (2014): Catecismo e Liberalismo em Portugal e no México
Demand side management for the future smart grid
Creators: name: Samadi Dinani, Pedram
Publisher: name: University of British Columbia
Year: 2015

description: To achieve a high level of reliability and robustness in power systems, the grid is usually designed for the peak demand rather than the average demand. This usually results in an under-utilized system. Demand side management (DSM) programs can be adopted to shape the load pattern of the users to better utilize the available power generation capacity and to prevent installing new generation and transmission infrastructures. In this thesis, we propose different algorithms for DSM. First, we focus on the problem of maximizing the social welfare of the users. We consider a scenario where the users are equipped with automated control units and are able to make price-responsive decisions. We propose a Vickrey-Clarke-Groves (VCG) mechanism to maximize the social welfare of the users. Subsequently, we focus on developing a novel automated load scheduling algorithm to minimize the energy expenses of the user. The proposed algorithm takes into account the effects of the load uncertainties in future time slots. Moreover, the operational constraints of different types of appliances including must-run appliances, and interruptible and non-interruptible controllable appliances are studied. Next, we study how the utility company can set price values for different times of a day such that the peak-to-average ratio (PAR) of the load is minimized. We also consider the effects of the uncertainty regarding the price-responsiveness of the users. To simulate the likely behavior of the users in response to different price values for different times of the day, we propose the use of a system simulator unit. We propose two pricing algorithms based on stochastic approximation aiming to minimize the PAR of the aggregate load. Finally, we consider systems with high penetration of renewable energy resources. To tackle the reverse power flow problem associated with these systems, we propose a joint load scheduling and trading algorithm. This algorithm encourages the users to sell their excess generation to their neighboring users which mitigates the reverse power flow problem.
The use of high-throughput amplicon deep sequencing to explore aquatic virus communities
Creators: name: Tian, Xi
Publisher: name: University of British Columbia
Year: 2015

description: Viruses are the most abundant biological entity in aquatic ecosystems. In each milliliter of marine or fresh water, there are typically between one to ten million viruses. Aquatic viruses influence microbial diversity, mortality and evolution, which in turn affect biogeochemical cycles and energy fluxes in marine ecosystems. As most aquatic microbes have not been cultured, the viruses which infect them cannot be cultured; hence, non-culture based approaches are needed to ascertain changes in the composition and diversity of virus communities. This research involves using PCR amplicons and high-throughput sequencing to uncover unknown diversity in marine and freshwater viruses and determine its temporal and spatial variation. Differences in the taxonomic profiles of viruses in the families Phycodnaviridae, Myoviridae, and Podoviridae across marine locations were assessed using 454 pyrosequencing. Temporal and spatial changes in the taxonomic profiles of viruses in the family Myoviridae were assessed in a stream using Illumina sequencing. Results show that high-throughput sequencing of marker genes is a robust method to explore viral diversity, and revealed many previously unknown Operational Taxonomic Units (OTUs). Furthermore, distributions of OTUs within virus families differed markedly among samples, indicating that the virus distributions were spatially dynamic. Moreover, the variation of OTUs within the freshwater Myoviridae communities suggested that some OTUs could be used as indicators of agricultural runoff.
A Ti/Pt/Co multilayer stack for transfer function based magnetic force microscopy calibrations
Creators: name: Sakar, Baha
name: Sievers, Sibylle
name: Scarioni, Alexander Fernandez
name: Garcia-Sanchez, Felipe
name: Oztoprak, Ilker
name: Schumacher, Hans Werner
name: Ozturk, Osman
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Magnetic force microscopy is a widespread technique for imaging magnetic structures with a resolution of some 10 nanometers. MFM can be calibrated to obtain quantitative spatially resolved magnetization data in units of A/m by determining the calibrated point spread function of the instrument, its instrument calibration function (ICF), from a measurement of a well-known reference sample. Beyond quantifying the MFM data, a deconvolution of the MFM image data with the ICF also corrects the smearing caused by the finite width of the MFM tip stray field distribution. However, the quality of the calibration depends critically on the calculability of the magnetization distribution of the reference sample. Here, we discuss a Ti/Pt/Co multilayer stack that shows a stripe domain pattern as a suitable reference material. A precise control of the fabrication process, combined with a characterization of the sample micromagnetic parameters, allows reliable calculation of the sample's magnetic stray field, proven by a very good agreement between micromagnetic simulations and qMFM measurements. A calibrated qMFM measurement using the Ti/Pt/Co stack as a reference sample is shown and validated, and the application area for quantitative MFM measurements calibrated with the Ti/Pt/Co stack is discussed
description: 24 page 12 Picture