cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Angular Momentum Transport in Protoplanetary and Black-Hole Accretion Disks: The Role of Parasitic Modes in the Saturation of MHD Turbulence
Creators: name: Pessah, Martin E.
Publisher: name: arXiv
Year: 2009
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The magnetorotational instability (MRI) is considered a key process for driving efficient angular momentum transport in astrophysical disks. Understanding its non-linear saturation constitutes a fundamental problem in modern accretion disk theory. The large dynamical range in physical conditions in accretion disks makes it challenging to address this problem only with numerical simulations. We analyze the concept that (secondary) parasitic instabilities are responsible for the saturation of the MRI. Our approach enables us to explore dissipative regimes that are relevant to astrophysical and laboratory conditions that lie beyond the regime accessible to current numerical simulations. We calculate the spectrum and physical structure of parasitic modes that feed off the fastest, exact (primary) MRI mode when its amplitude is such that the fastest parasitic mode grows as fast as the MRI. We argue that this "saturation" amplitude provides an estimate of the magnetic field that can be generated by the MRI before the secondary instabilities suppress its growth significantly. Recent works suggest that the saturation amplitude of the MRI depends mainly on the magnetic Prandtl number. Our results suggest that, as long as viscous effects do not dominate the fluid dynamics, the saturation level of the MRI depends only on the Elsasser number $Λ_η$. We calculate the ratio between the stress and the magnetic energy density, $α_{\rm sat}β_{\rm sat}$, associated with the primary MRI mode. We find that for $Λ_η>1$ Kelvin-Helmholtz modes are responsible for saturation and $α_{\rm sat}β_{\rm sat} = 0.4$, while for $Λ_η< 1$ tearing modes prevail and $α_{\rm sat}β_{\rm sat} \simeq 0.5 \, Λ_η$. Several features of MRI simulations in accretion disks surrounding young stars and compact objects can be interpreted in terms of our findings.
description: 11 figures, 16 pages, uses emulateapj, updated to match published version in ApJ
Formation of late-type spiral galaxies: gas return from stellar populations regulates disk destruction and bulge growth
Creators: name: Martig, Marie
name: Bournaud, Frederic
Publisher: name: arXiv
Year: 2009
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Spiral galaxies have most of their stellar mass in a large rotating disk, and only a modest fraction in a central spheroidal bulge. This poses a major challenge for cosmological models of galaxy formation. Galaxies form at the centre of dark matter halos through a combination of hierarchical merging and gas accretion along cold streams, and should rapidly grow their bulge through mergers and instabilities. Cosmological simulations predict galaxies to have most of their mass in the central bulge, and therefore an angular momentum much below the observed level, except in dwarf galaxies. We propose that the continuous return of fresh gas by stellar populations over cosmic times could solve this issue. A population of stars formed at a given instant typically returns half of its initial mass in the form of gas over 10 billion years, and the process is not dominated by rapid supernovae explosions but by the long-term mass-loss from low- and intermediate-mass stars. Using simulations of galaxy formation, we show that this recycling of gas can strongly affect the structural evolution of massive galaxies, potentially solving the bulge fraction issue: we find that the bulge-to-disk ratio of a massive galaxy can be divided by a factor of 3. The continuous recycling of baryons through star formation and stellar mass loss helps the growth of disks and their survival to interactions and mergers. Instead of forming only early-type, spheroid-dominated galaxies (S0 and ellipticals), the standard cosmological model can then successfully account for massive late-type, disk-dominated spiral galaxies (Sb-Sc).
description: 6 pages, 4 figures, ApJL accepted. Movie available at http://marie.martig.free.fr/spiral/
Searches for Cosmic-String Gravitational-Wave Bursts in Mock LISA Data
Creators: name: Cohen, Michael I.
name: Cutler, Curt
name: Vallisneri, Michele
Publisher: name: arXiv
Year: 2010
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: A network of observable, macroscopic cosmic (super-)strings may have formed in the early universe. If so, the cusps that generically develop on cosmic-string loops emit bursts of gravitational radiation that could be detectable by both ground- and space-based gravitational-wave interferometers. Here we report on two versions of a LISA-oriented string-burst search pipeline that we have developed and tested within the context of the Mock LISA Data Challenges. The two versions rely on the publicly available MultiNest and PyMC software packages, respectively. To reduce the effective dimensionality of the search space, our implementations use the F-statistic to analytically maximize over the signal's amplitude and polarization, A and psi, and use the FFT to search quickly over burst arrival times t_C. The standard F-statistic is essentially a frequentist statistic that maximizes the likelihood; we also demonstrate an approximate, Bayesian version of the F-statistic that incorporates realistic priors on A and psi. We calculate how accurately LISA can expect to measure the physical parameters of string-burst sources. To understand LISA's angular resolution for string-burst sources, we draw maps of the waveform fitting factor [maximized over (A psi, t_C)] as a function of sky position; these maps dramatically illustrate why (for LISA) inferring the correct sky location of the emitting string loop will often be practically impossible. We also identify and elucidate several symmetries that are imbedded in this search problem, and we derive the distribution of cut-off frequencies f_max for observable bursts.
description: Final CQG version; 28 pages, 10 figures; higher-resolution plots available at http://www.vallis.org/publications/cosmicstrings
PROPERTIES AND CHARACTERISTICS OF NUCLEAR ENERGY
Creators: name: Jurakulov, Sanjar
Publisher: name: Zenodo
Year: 2023

description: Nuclear power is the most important sub-sector of the world energy industry, which began to make a significant contribution to the world's electricity production several decades ago. Today, the price of electricity produced by nuclear power plants allows us to talk about serious competition with other types of power plants. A clear advantage of nuclear power plants is the absence of aerosol and greenhouse gas emissions into the atmosphere.
The geometry of dual complexes
Creators: name: Mauri, Mirko
Publisher: name: Imperial College London
Year: 2019

description: In this thesis we examine some aspects of the topology of dual complexes under three different viewpoints: birational, non-archimedean and symplectic. Our main source of inspiration is the question raised by Kollár and Xu, whether the dual complex of a log Calabi–Yau pair is a quotient of a sphere. Complete proofs exist only in low dimension, smaller than 4, or conditionally in dimension 5. We contribute to providing new evidence in any dimension. First, using the connectivity theorems of the Minimal Model Program, we answer the question positively for Mori fibre spaces of low Picard numbers or of low-dimensional bases. No assumption on the dimension of the total space is imposed. We also compute the dual complex of special log Calabi–Yau pairs of great interest in non-abelian Hodge theory. This provides the first non-trivial evidence for the geometric P=W conjecture of Katzarkov–Noll–Pandit–Simpson in the compact case. To this end, we define the essential skeleton of a pair over a trivially-valued field as the minimality locus of weight functions on the Berkovich analytification. In analogy to the case of degenerations, we show that the weight functions are defined in terms of the classical notion of log discrepancy, and more intrinsically, in terms of a canonical metric, called Temkin’s metric. Finally, we provide a general technique for constructing Lagrangian torus fibrations on affine varieties, whose bases are the skeletons of one of their compactifications. In particular, we provide a Lagrangian version of Mikhalkin’s tropicalisation of the pair-of-pants, and a Lagrangian fibration on the 3-fold negative vertex with codimension 2 discriminant locus, answering an old question of Gross. We also construct an analogue of the non-archimedean SYZ fibration studied by Nicaise, Xu and Yu.
Variations on Debris Disks II. Icy Planet Formation as a Function of the Bulk Properties and Initial Sizes of Planetesimals
Creators: name: Kenyon, Scott J.
name: Bromley, Benjamin C.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We describe comprehensive calculations of the formation of icy planets and debris disks at 30-150 AU around 1-3 solar mass stars. Disks composed of large, strong planetesimals produce more massive planets than disks composed of small, weak planetesimals. The maximum radius of icy planets ranges from roughly 1500 km to 11,500 km. The formation rate of 1000 km objects - `Plutos' - is a useful proxy for the efficiency of icy planet formation. Plutos form more efficiently in massive disks, in disks with small planetesimals, and in disks with a range of planetesimal sizes. Although Plutos form throughout massive disks, Pluto production is usually concentrated in the inner disk. Despite the large number of Plutos produced in many calculations, icy planet formation is inefficient. At the end of the main sequence lifetime of the central star, Plutos contain less than 10% of the initial mass in solid material. This conclusion is independent of the initial mass in the disk or the properties of planetesimals. Debris disk formation coincides with the formation of planetary systems containing Plutos. As Plutos form, they stir leftover planetesimals to large velocities. A cascade of collisions then grinds the leftovers to dust, forming an observable debris disk. In disks with small (< 1-10 km) planetesimals, collisional cascades produce luminous debris disks with maximum luminosity roughly 0.01 times the stellar luminosity. Disks with larger planetesimals produce much less luminous debris disks. Observations of debris disks around A-type and G-type stars strongly favor models with small planetesimals. In these models, our predictions for the time evolution and detection frequency of debris disks agree with published observations. We suggest several critical observations that can test key features of our calculations.
description: 61 pages of text, 24 tables, and 34 figures; submitted to ApJS; comments welcome; revised version accepted to ApJS, changed text, modified tables, added references, no major changes to conclusions
A decomposition of waves in time series of data related to Covid-19, applied to study the role of Alpha variant in the spread of infection
Creators: name: Sparavigna, Amelia Carolina
Publisher: name: Zenodo
Year: 2021
Subjects: Time-series Decomposition
Weibull functions
kappa-Weibull functions
Threshold
Variants of Sars-CoV-2
Covid-19
Alpha Variant
B.1.1.7
Gaussian pdf
probability distribution function

description: Here it is proposed a decomposition in components of the “waves” which appear in the time series of data related to Covid-19 pandemic. The decomposition is based on functions of κ-statistics; in particular the κ-Weibull is used. Fitted data are those of the “waves” ranging from August 2020 to April 2021 in the United Kingdom, from September 2020 to May 2021 in Ireland, and from September 2020 to June 2021 in Italy. For the United Kingdom, the time series of daily infection shows a wave composed by two peaks. Among the many factors involved in the spread of infection, it seems that, in driving the onset of the second peak, the main role was played by the emergence of Alpha variant of Sars-Cov-2. For what concerns data from Ireland, if we decompose the analysed “wave” in three components, we can observed that for one of them the role of the Alpha variant was relevant for sure. In the case of Italy, the effect is less evident, because it was spread over a larger time interval.
Search for galactic H2+
Creators: name: Sloan, David Scott
Publisher: name: University of British Columbia
Year: 2011

description: The design and construction of a digital autocorrelation spectometer for radio astronomy is described. It is a 16 channel device with an overall bandwidth of 2 MHz. Extensive use was made of integrated circuitry. The use of the spectrometer in a search for singly ionized molecular hydrogen (Hg₂⁺) is described. The search covered a frequency range 1404 to 1409 MHz for the radio sources NML Cygnus and the Omega Nebula down to a level of T[subscript b] 0.25 K.
A discrete time neural network model with spiking neurons II. Dynamics with noise
Creators: name: Cessac, B.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Dynamical Systems (math.DS)
subject: Probability (math.PR)
subject: Biological Physics (physics.bio-ph)
subject: Neurons and Cognition (q-bio.NC)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: We provide rigorous and exact results characterizing the statistics of spike trains in a network of leaky integrate and fire neurons, where time is discrete and where neurons are submitted to noise, without restriction on the synaptic weights. We show the existence and uniqueness of an invariant measure of Gibbs type and discuss its properties. We also discuss Markovian approximations and relate them to the approaches currently used in computational neuroscience to analyse experimental spike trains statistics.
description: 43 pages - revised version - to appear il Journal of Mathematical Biology
Fabrication and development of high-aspect-ratio nanostructures for biointerfacing
Creators: name: Becce, Michele
Publisher: name: Imperial College London
Year: 2019

description: This thesis describes the optimisation of the fabrication protocols for vertically-aligned nanostructures to be interfaced with living cells. The dissertation is organised around four aims. The first aim describes the optimisation of a nanoneedle fabrication process. Nanoneedles are regular arrays of conical mesoporous-silicon nanostructures, recently developed by the Stevens Group. The second aim describes one potential novel development for nanoneedles, in the field of biosensing. This involves the selective deposition of silver nanoparticles at the nanoneedle tips, in order to take advantage of Raman-spectroscopy-signal-enhancement phenomena. These were envisioned to facilitate the detection of Raman-active molecules, as well as the investigation of cellular processes. The third aim represents another direction in broadening the horizon of the nanoneedle applications, in the field of cell transfection. This concerns the fabrication of interdigitated, planar electrodes, having nanoneedle-bearing digits. This way, a portable device was envisioned, which could exploit tip-field-enhanced electroporation, as well as tight membrane interface, for improved delivery of molecules to cells. The fourth aim describes the optimisation of the fabrication of nanowires. These were interfaced with bacteria, for prokaryotic-cell transformation purposes. This project is conceptually similar to the nanoneedle-mediated delivery of molecules that has been proven in the literature, but on a smaller scale. Bacteria cells are indeed smaller that eukaryotic ones, thus smaller nanostructures were developed to deliver cargoes into them. This thesis aims to give a contribution to the field of vertically-aligned nanostructures for nanomedicine. This field needs further insights before devices can be used in clinical settings but holds great promises for the future.
The ACS Nearby Galaxy Survey Treasury II. Young Stars and their Relation to Halpha and UV Emission Timescales in the M81 Outer Disk
Creators: name: Gogarten, Stephanie M.
name: Dalcanton, Julianne J.
name: Williams, Benjamin F.
name: Seth, Anil C.
name: Dolphin, Andrew
name: Weisz, Daniel
name: Skillman, Evan
name: Holtzman, Jon
name: Cole, Andrew
name: Girardi, Leo
name: de Jong, Roelof S.
name: Karachentsev, Igor D.
name: Olsen, Knut
name: Rosema, Keith
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We have obtained resolved stellar photometry from Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) observations of a field in the outer disk of M81 as part of the ACS Nearby Galaxy Survey Treasury (ANGST). Motivated by the recent discovery of extended UV (XUV) disks around many nearby spiral galaxies, we use the observed stellar population to derive the recent star formation histories of five ~0.5 kpc-sized regions within this field. These regions were selected on the basis of their UV luminosity from GALEX and include two HII regions, two regions which are UV-bright but Halpha-faint, and one "control" region faint in both UV and Halpha. We estimate our effective SFR detection limit at ~2 x 10^-4 Msun/yr, which is lower than that of GALEX for regions of this size. As expected, the HII regions contain massive main sequence stars (in the mass range 18-27 Msun, based on our best extinction estimates), while similar massive main sequence stars are lacking in the UV-bright/Halpha-faint regions. The observations are consistent with stellar ages <10 Myr in the HII regions, and >16 Myr in the UV-bright/Halpha-faint regions. All regions but the control have formed ~10^4 Msun of stars over the past ~65 Myr. Thus, our results, for at least one small area in the outer disk of M81, are consistent with an age difference being sufficient to explain the observed discrepancy between star-forming regions detected in Halpha and those detected exclusively in UV. However, our data cannot conclusively rule out other explanations, such as a strongly truncated initial mass function (IMF).
description: 18 pages, 12 figures, accepted for publication in ApJ, paper with full resolution figures available: http://www.nearbygalaxies.org/papers/M81_Halpha_uv.pdf
MPEC 2023-Y04 : 2023 XV14
Creators: name: Minor Planet Center Staff
Publisher: name: The Minor Planet Center
Year: 2023
Subjects: subject: Small Solar System bodies
valueUri: http://astrothesaurus.org/uat/1469
subject: 2023 XV14

description: The Minor Planet Electronic Circulars contain information on unusual minor planets, routine data on comets and natural satellites, and occasional editorial announcements.  They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Radiative transition probabilities between the 3p54s and 3p54p configurations of argon
Creators: name: Jacobson, Thor Victor
Publisher: name: University of British Columbia
Year: 2011

description: The absolute transition probabilities between the 3p⁵4s and 3p⁵4p configurations of neutral argon have been measured in a three part experiment. In the first experiment, a technique of absorption spectroscopy was used to obtain relative transition probabilities for spectral lines with a common lower level. Secondly, relative transition probabilities were obtained for spectral lines with a common upper level by measuring the relative intensities of suitable pairs of lines in an emission experiment. In the third experiment, the relative values were converted to absolute transition probabilities by obtaining the lifetime of the P₁-S2 transition at ʎ7503Å. The experimental techniques used in this experiment were developed by Robinson (1966) and van Andel (1966).
Turbo Packet Combining Strategies for the MIMO-ISI ARQ Channel
Creators: name: Ait-Idir, Tarik
name: Saoudi, Samir
Publisher: name: arXiv
Year: 2009
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: This paper addresses the issue of efficient turbo packet combining techniques for coded transmission with a Chase-type automatic repeat request (ARQ) protocol operating over a multiple-input--multiple-output (MIMO) channel with intersymbol interference (ISI). First of all, we investigate the outage probability and the outage-based power loss of the MIMO-ISI ARQ channel when optimal maximum a posteriori (MAP) turbo packet combining is used at the receiver. We show that the ARQ delay (i.e., the maximum number of ARQ rounds) does not completely translate into a diversity gain. We then introduce two efficient turbo packet combining algorithms that are inspired by minimum mean square error (MMSE)-based turbo equalization techniques. Both schemes can be viewed as low-complexity versions of the optimal MAP turbo combiner. The first scheme is called signal-level turbo combining and performs packet combining and multiple transmission ISI cancellation jointly at the signal-level. The second scheme, called symbol-level turbo combining, allows ARQ rounds to be separately turbo equalized, while combining is performed at the filter output. We conduct a complexity analysis where we demonstrate that both algorithms have almost the same computational cost as the conventional log-likelihood ratio (LLR)-level combiner. Simulation results show that both proposed techniques outperform LLR-level combining, while for some representative MIMO configurations, signal-level combining has better ISI cancellation capability and achievable diversity order than that of symbol-level combining.
description: 13 pages, 7 figures, and 2 tables
„Ich traue mir zu …“
Creators: name: Beudels, Melanie
name: Schroeder, Nadine
name: Preisfeld, Angelika
Publisher: name: PraxisForschungLehrer*innenBildung. Zeitschrift für Schul- und Professionsentwicklung.
Year: 2021

description: Viele (zukünftige) Sachunterrichtslehrkräfte haben geringe Selbstwirksamkeitserwartungen und teils auch ein geringes Interesse hinsichtlich des Unterrichtens von naturwissenschaftlichen und technischen Inhalten. Gleichzeitig mangelt es an der Beforschung von universitären Lehrkonzepten, welche versuchen, die Entwicklung dieser motivationalen Orientierungen in Bezug auf mehrere sachunterrichtliche Bezugsfächer parallel positiv zu beeinflussen. Dies ist auch aufgrund des perspektivenvernetzenden Charakters des Faches relevant. Im Beitrag wird daher mithilfe eines quasi-experimentellen Pre-Post-Interventions-Baseline-Gruppen-Designs untersucht, ob sich durch einen Kurs, in dem die Bezugsfächer Biologie, Chemie, Physik und Technik vernetzt vermittelt werden, die Interessen und Selbstwirksamkeitserwartungen von n = 202 Grundschullehramtsstudierenden verändern. Während sich in der Baselinegruppe, die nicht an der Lehrveranstaltung teilnahm, die Selbstwirksamkeitserwartungen nicht signifikant ändern und die Interessen teils abnehmen, ist bei der Interventionsgruppe eine positive Entwicklung – gerade in Bezug auf die Selbstwirksamkeitserwartungen – festzustellen. Es zeigt sich zudem bei der Entwicklung der Sachinteressen ein leichter Vorteil für die Teilnehmenden der Lehrveranstaltung als Blockkursformat im Gegensatz zu jenen, die an einem wöchentlichen Format partizipierten. Keine signifikanten Unterschiede in der Veränderung der motivationalen Orientierungen bestehen hinsichtlich des Studienschwerpunktes. Grundschullehramtsstudierende mit und ohne ‚Naturwissenschaften und Technik‘ als Studienfach profitieren gleichermaßen von der Lehrveranstaltung.
description: PraxisForschungLehrer*innenBildung. Zeitschrift für Schul- und Professionsentwicklung., Bd. 3 Nr. 1 (2021): PraxisForschungLehrer*innenBildung – Ausgabe 3
RESEARCH THEORIES OF PHYSICS COURSES IN JAPAN
Creators: name: Jurakulov, Sanjar
Publisher: name: Zenodo
Year: 2023

description: The purpose of this study is to explain in-service programs for science and physics teachers in Japan. This study specifically discusses the "course research" approach. "Lesson research" is an approach used in teacher training. Lesson Research was developed in Japan and has been successfully used in teacher training in many countries. Document review, one of the qualitative research methods, was used to collect data for this study conducted in a survey model. When document analysis was carried out in the study, efforts were made to access primary sources, documents were analyzed and data were analyzed and presented.
Coactions of Hopf C*-bimodules
Creators: name: Timmermann, Thomas
Publisher: name: arXiv
Year: 2009
Subjects: subject: Operator Algebras (math.OA)
subject: Quantum Algebra (math.QA)
subject: FOS: Mathematics
subject: 46L55, 22A22, 20G42

description: Coactions of Hopf C*-bimodules simultaneously generalize coactions of Hopf C*-algebras and actions of groupoids. Following an approach of Baaj and Skandalis, we construct reduced crossed products and establish a duality for fine coactions. Examples of coactions arise from Fell bundles on groupoids and actions of a groupoid on bundles of C*-algebras. Continuous Fell bundles on an etale groupoid correspond to coactions of the reduced groupoid algebra, and actions of a groupoid on a continuous bundle of C*-algebras correspond to coactions of the function algebra.
description: 44 pages, to appear in the Journal of Operator theory
Development and application of advanced analytical strategies for understanding paracetamol metabolism and toxicity.
Creators: name: Dargue, Rebecca
Publisher: name: Imperial College London
Year: 2019

description: Paracetamol (N-acetyl-p-aminophenol [APAP]) has been authorised in the United Kingdom as an analgesic and antipyretic therapy for over 60 years. When ingested at supratherapeutic doses, its hepatic metabolism is altered from a non-toxic route via conjugations, with sulfate or glucuronic acid, to an oxidative pathway of metabolism via cytochrome p450 (CYP) enzymes resulting in the formation of the reactive intermediate N-acetyl-p-benzoquinone imine (NAPQI). This reacts with glutathione (GSH), depleting this in the liver, causing APAP induced liver injury. APAP overdose is the largest cause of acute liver failure (ALF) in the UK and the second largest cause of liver transplantation world-wide. In England and Wales APAP overdose results in around 100 000 hospital admissions per year, of which 50% result in extended stays, and contributes to around 150 deaths. While improved treatments for APAP-induced liver injury are being developed, it is important to understand how to predict the severity of liver injury; to reduce unnecessary hospital stays and the number of deaths. The hypotheses for the work described below are that GSH depletion following APAP activation to NAPQI is a major route of APAP toxicity, and metabolites related to GSH biosynthesis, including 5-oxoproline (5-OP) and ophthalmic acid (OA), are circulating biomarkers for GSH depletion. In addition, APAP- glutathione conjugate (APAP-SG) and related metabolites, are predictive of liver injury. For the development of new therapies, animal models of APAP overdose are required. A detailed knowledge of the routes of APAP metabolism in these species is crucial for understanding their translation to human. Analytical methods have been developed and applied to samples from animal models and patients. Plasma/serum concentrations of 5-OP have been shown to be a promising biomarker across animal models and human patients, especially when used in combination with concentrations of alanine aminotransferase (ALT) and glutathione-derived APAP conjugates.
Zero-one laws for connectivity in random key graphs
Creators: name: Yagan, Osman
name: Makowski, Armand M.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Combinatorics (math.CO)
subject: Probability (math.PR)
subject: FOS: Mathematics

description: The random key graph is a random graph naturally associated with the random key predistribution scheme of Eschenauer and Gligor for wireless sensor networks. For this class of random graphs we establish a new version of a conjectured zero-one law for graph connectivity as the number of nodes becomes unboundedly large. The results reported here complement and strengthen recent work on this conjecture by Blackburn and Gerke. In particular, the results are given under conditions which are more realistic for applications to wireless sensor networks.
description: 16 pages
La manualistica genovese per la preparazione degli uomini d'affari
Creators: name: Zanini, Andrea
Publisher: name: Zenodo
Year: 2005
Subjects: History of Education
Early modern businessmen
Financial history

description: This essay presents an overview of textbooks devoted to professional education of merchants and businessmen in 17th and 18th Genoa and points out some issues deriving from these little-known printed sources.
description: {"references": ["Borlandi, F. (1963). La formazione culturale del mercante genovese nel medioevo, Atti della Societ\u00e0 Ligure di Storia Patria, n.s, 3(2), 221-230.", "Doria, G. (1995). Comptoirs, foires de changes et places \u00e9trang\u00e8res: les lieux d'apprentissage des nobles n\u00e9gociants de G\u00eanes entre Moyen \u00c2ge et \u00e2ge baroque, in F. Angiolini, D. Roche (dir.). Cultures et formations n\u00e9gociantes dans l'Europe moderne, Paris, 321-347.", "Felloni, G., (2005). Genova e la storia della finanza: una serie di primati? Genoa and the History of Finance: a Series of Firsts?, Genova", "Hoock, J., Jeannin, P, hrsg. von (1991-2001), Ars Mercatoria. Handb\u00fccher und Traktate f\u00fcr den Gebrauch des Kaufmanns, 1470-1820, Padeborn (3 voll.).", "Jeannin, P. (1991). De l'aritmetique commerciale \u00e0 la pratique bancarie: l'escompte aux XVIe-XVIIe si\u00e8cles, in Banchi pubblici, banchi privati e monti di piet\u00e0 nell'Europa preindustriale, Genova, 1, 95-116.", "Massa, P. (1986-87). \"Fra teoria e pratica mercantile: il \"negotiante\" Gio. Domenico Peri (1590-1666)\", Annali della Facolt\u00e0 di Giurisprudenza di Genova, 21(1-2), 800-812.", "Massa, P. (1995). Dalla \"bottega\" ai corsi universitari\", in P. Massa, Lineamenti di organizzazione economica in uno Stato preindustriale: la Repubblica di Genova, Genova, 443-455.", "Massa, P. (2001). Cultura e tecnica commerciale nella storia della formazione professionale a Genova tra XIX e XX secolo, in M. Martini, L. Zan (a cura di). Computisti, ragionieri, aziendalisti. La costruzione di una professione e di una disciplina tra Otto e Novecento, Padova, 269-288.", "Piccinno, L. (2001). \"La riflessione economica in Liguria tra scienza e pratica (secoli XVI-XIX)\", Storia Economica, 4(2), 279-327.", "Piccinno, L., Zanini A. (2004). Cultura economica e cultura mercantile: idee e protagonisti\", in C. Bitossi (a cura di). Erudizione e storiografia settecentesche in Liguria, Genova, 563-595.", "Zanini A. (2003). \"Abaco e aritmetica mercantile a Genova nel XVII secolo: i manuali e la scuola di David Veronese\", Atti della Accademia Ligure di Scienze e Lettere, 6(1), 225-256, https://doi.org/10.5281/zenodo.3976814"]}
An estimate of the number of apparent singularities in the Riemann-Hilbert problem on a compact Riemann surface
Creators: name: Artamonov, D. V.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: Complex Variables (math.CV)
subject: FOS: Mathematics
subject: 34M45, 34M50

description: In the paper we give an upper estimate of the number of apparent singularities that are sufficient for construction of a system of linear differential equations on a Riemann surface with given fuchsian singularities and monodromy.
description: 8 pages. Several typos are corrected
Long lived central engines in Gamma Ray Bursts
Creators: name: Ghisellini, G.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The central engine of Gamma Ray Bursts may live much longer than the duration of the prompt emission. Some evidence of it comes from the presence of strong precursors, post-cursors, and X-ray flares in a sizable fraction of bursts. Additional evidence comes from the fact that often the X-ray and the optical afterglow light curves do not track one another, suggesting that they are two different emission components. The typical "steep-flat-steep" behavior of the X-ray light curve can be explained if the same central engine responsible for the main prompt emission continues to be active for a long time, but with a decreasing power. The early X-ray "afterglow" emission is then the extension of the prompt emission, originating at approximately the same location, and is not due to forward shocks. If the bulk Lorentz factor Gamma is decreasing in time, the break ending the shallow phase can be explained, since at early times Gamma is large, and we see only a fraction of the emitting area. Later, when Gamma decreases, we see an increasing fraction of the emitting surface up to the time when Gamma ~ 1/theta_j. This time ends the shallow phase of the X-ray light curve. The origin of the late prompt emission can be the accretion of the fall-back material, with an accretion rate dot M proportional to t^(-5/3). The combination of this late prompt emission with the flux produced by the standard forward shock can explain the great diversity of the optical and the X-ray light curves.
description: 6 pages, 6 figures, To appear in: 2008 Nanjing GRB Conference, AIP, Eds. Y.F. Huang, Z.G. Dai, B. Zhang
IMPACT OF THE MINING INDUSTRY ON PEOPLE AND THE ENVIRONMENT
Creators: name: Jurakulov, Sanjar
Publisher: name: Zenodo
Year: 2023

description: The article considers the impact of the mining industry on people and the environment, pollution of nature, pollution of the environment, negative consequences of using natural resources. Rational use of minerals, processes of their extraction and processing, methods of uranium extraction are important. Since the beginning of mankind, all natural resources of the earth's crust have been happily used for their needs. For this purpose, more than a million tons of natural land landscapes have been developed.
Androgen signalling-modulatory microRNAs: roles in prostate cancer progression and therapy
Creators: name: Kalofonou, Foteini
Publisher: name: Imperial College London
Year: 2019

description: In the UK, prostate cancer is the most common cancer and the second most common cause of cancer related death amongst men. Prostate cancer is an androgen dependent malignancy that initially responds well to androgen ablation therapy. However, despite hormonal treatment, hormone unresponsive prostate cancer eventually emerges and may lead to death. Current diagnostic and therapeutic strategies have many limitations and it is imperative to identify new biomarkers and therapeutic targets for this condition. MicroRNAs have emerged over the years as potential biomarkers and therapeutic targets. MicroRNAs are small, non-coding RNAs that regulate gene silencing through the inhibition of translation and mRNA degradation, and function both as oncogenes, and as tumour suppressors. Circulating microRNAs potentially have a significant role as diagnostic, and prognostic markers and microRNAs and their inhibitors, in the form of antisense oligonucleotides, have therapeutic potential as regulators of gene expression. Work in this thesis has focused on the role of miR-1271-5p, an AR-modulatory microRNA, and miR-27a-3p in prostate cancer progression and therapy. I report that miR-1271-5p has androgenic potential, is implicated in disease progression and has therapeutic potential. In work described in this thesis, miR-27a-3p has been found to be an androgen receptor modulatory oncomiR in prostate cancer cell lines, and to have therapeutic potential in castrate resistant prostate cancer. The predicted targets of both miR-27a-3p and miR-1271-5p include genes with roles in growth arrest, apoptosis and DNA repair. It is hoped that the elucidation of the molecular and biological role of these microRNAs and their target genes in prostate cancer, will provide us with a better understanding of disease development and lay the foundation for further advances in the diagnosis and treatment of prostate cancer.
Mapping all classical spin models to a lattice gauge theory
Creators: name: Cuevas, G. De las
name: Dür, W.
name: Briegel, H. J.
name: Martin-Delgado, M. A.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Quantum Physics (quant-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: In our recent work [Phys. Rev. Lett. 102, 230502 (2009)] we showed that the partition function of all classical spin models, including all discrete standard statistical models and all Abelian discrete lattice gauge theories (LGTs), can be expressed as a special instance of the partition function of a 4-dimensional pure LGT with gauge group Z_2 (4D Z_2 LGT). This provides a unification of models with apparently very different features into a single complete model. The result uses an equality between the Hamilton function of any classical spin model and the Hamilton function of a model with all possible k-body Ising-type interactions, for all k, which we also prove. Here, we elaborate on the proof of the result, and we illustrate it by computing quantities of a specific model as a function of the partition function of the 4D Z_2 LGT. The result also allows one to establish a new method to compute the mean-field theory of Z_2 LGTs with d > 3, and to show that computing the partition function of the 4D Z_2 LGT is computationally hard (#P hard). The proof uses techniques from quantum information.
description: 21 pages, 21 figures; published version
Influence of loading arrangement on shear enhancement in reinforced concrete beams
Creators: name: Filiagi Pastore, Marcus
Publisher: name: Imperial College London
Year: 2020

description: Shear enhancement occurs in reinforced concrete beams when loads are applied within around 2d of supports where d is the beam effective depth. This thesis examines shear enhancement in beams that are loaded both within 2d of supports and at 3d where shear enhancement is minimal. This loading arrangement (LA) frequently occurs in practice but has not previously been studied. The research combines laboratory testing, nonlinear finite element analysis (NLFEA) and analytical work. In total twelve beams, without and with shear reinforcement, were tested in three groups of four. Digital image correlation was used to determine the kinematics of the critical shear crack in each beam. The resulting crack displacements were inserted into constitutive models to estimate the contributions to shear resistance of aggregate interlock, dowel action, residual tensile strength, flexural compression zone and shear reinforcement. The relative contribution of each shear transfer action is shown to vary during loading and be dependent on the location and shape of the critical shear crack. For short-span beams, the dominant shear resisting mechanism is the flexural compression zone. For slender beams, the prevalent mechanism at peak load is aggregate interlock for beams without links and shear reinforcement otherwise. The measured beam strengths are evaluated against the predictions of NLFEA, strut-and-tie models (STMs), recent shear models from the literature and various international design standards. A novel STM is developed for beams simultaneously loaded with concentrated loads positioned within and outside 2d of supports. The accuracy of the STM predictions is improved by relating strut strength to the longitudinal strain in the reinforcement at the bottom node. The considered STMs are significantly more accurate than the considered design codes for the tested beams. Tests and NLFEA suggest that the shear resistance of beams with shear reinforcement depends on the angle of the failure plane.
Wave-train induced unpinning of weakly anchored vortices in excitable media
Creators: name: Pumir, Alain
name: Sinha, Sitabhra
name: Sridhar, S.
name: Argentina, Mederic
name: Horning, Marcel
name: Filippi, Simonetta
name: Cherubini, Christian
name: Luther, Stefan
name: Krinsky, Valentin
Publisher: name: arXiv
Year: 2009
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Pattern Formation and Solitons (nlin.PS)
subject: Tissues and Organs (q-bio.TO)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: A free vortex in excitable media can be displaced and removed by a wave-train. However, simple physical arguments suggest that vortices anchored to large inexcitable obstacles cannot be removed similarly. We show that unpinning of vortices attached to obstacles smaller than the core radius of the free vortex is possible through pacing. The wave-train frequency necessary for unpinning increases with the obstacle size and we present a geometric explanation of this dependence. Our model-independent results suggest that decreasing excitability of the medium can facilitate pacing-induced removal of vortices in cardiac tissue.
description: Published version
Supplemental table for "Postgraduate education among family and community physicians in Brazil: the Trajetórias MFC project"
Creators: name: Fontenelle, Leonardo Ferreira
name: Rossi, Stephani Vogt
name: Oliveira, Miguel Henrique Moraes de
name: Brandão, Diego José
name: Sarti, Thiago Dias
Publisher: name: Zenodo
Year: 2019

description: This is the supplemental table for manuscript "Postgraduate education among family and community physicians in Brazil: the Trajetórias MFC project". Please refer to the manuscript for background. The table is in the CSV (comma-separated values) format, delimited with semicolon and encoded in UTF-8 with byte-order mark (there are special characters due to the Portuguese language). It can be opened with desktop or Web application software (LibreOffice Calc, Microsoft Excel, Google Sheets) or with statistical software such as R.
Crowd Counting Using CNN
Creators: name: Journal IJIRT
Publisher: name: figshare
Year: 2021
Subjects: Computer Engineering

description: - Increase in population all over the world has opened a pathway to large gatherings for many causes. It might be grand openings of hotels and institutions, award ceremony, local football matches, riots and much more. Analysing the crowd formation before is quite a difficult task and therefore would not come under control. Due to this, many accidents have occurred in the past taking away innocent lives. The technique, which is Crowd Counting, is an approach to analyse and detect the crowd, that is, to estimate the number of people gathered in a certain area. In this paper, a CNN model is presented to estimate the count of a particular crowd. We have implemented the VGG-16 model for a deep layered image classification and henceforth a better understanding of each image. Shanghai Crowd Counting Dataset has been used which contains more than 400 images for training and testing.
DIDACTIC TEACHING PROCESS IN PEDAGOGY AS A WHOLE SYSTEM.
Creators: name: Rahimberdiyeva, Mahfuza
name: Komilova, Umida
name: Umarova, Umida
Publisher: name: Zenodo
Year: 2023

description: This article discusses the specific features of primary education didactics and gives methodical recommendations. Also, the formation of the teaching process as a whole system and its importance in the educational process are discussed.
Stabilization of the p-wave superfluid state in an optical lattice
Creators: name: Han, Y. -J.
name: Chan, Y. -H.
name: Yi, W.
name: Daley, A. J.
name: Diehl, S.
name: Zoller, P.
name: Duan, L. -M.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: It is hard to stabilize the p-wave superfluid state of cold atomic gas in free space due to inelastic collisional losses. We consider the p-wave Feshbach resonance in an optical lattice, and show that it is possible to have a stable p-wave superfluid state where the multi-atom collisional loss is suppressed through the quantum Zeno effect. We derive the effective Hamiltonian for this system, and calculate its phase diagram in a one-dimensional optical lattice. The results show rich phase transitions between the p-wave superfluid state and different types of insulator states induced either by interaction or by dissipation.
description: 5 pages, 5 figures
Materials engineering strategies on nanostructured WO3 photoanodes for solar water splitting
Creators: name: Malms, Lukas
Publisher: name: Imperial College London
Year: 2020

description: Photoelectrochemical water splitting cells could offer a simple, yet efficient approach to solar hydrogen production. Known materials lack the required efficiencies and stabilities to make this process commercially viable, however. This thesis aims to contribute to our understanding of existing materials engineering strategies and to develop new approaches to the design of efficient WO3 based photoanodes. The results of a full factorial optimisation strategy for the synthesis of hydrothermal WO3 nanorod photoanodes are presented first. The external quantum efficiencies of the optimised photoanodes are amongst the highest photon conversion efficiencies reported to date for nanostructured WO3, demonstrating that the full factorial approach can be effective in designing high efficiency WO3 photoanodes. The optimised photoanodes exhibit comparatively fast electron extraction kinetics, which, in contrast to previous studies, shift to earlier timescales with increasing anodic bias. Measurements of charge extraction kinetics as a function of oxygen vacancy concentration demonstrate that this difference in bias dependence can be attributed to a comparatively small degree of oxygen deficiency in these photoanodes. Photovoltammetry measurements in the presence of hole scavengers suggest that bulk recombination limits photoanode performance at all biases, while surface recombination is only limiting at low anodic biases. Motivated by these findings, the impacts of electrocatalyst deposition on photoanode performance are finally investigated. Two different Earth abundant electrocatalysts were chosen for this purpose: FeOx and CoFePbOx. Interestingly, both catalysts have a similar impact on performance. Deposition of either catalyst improves photoanode activity at low biases but reduces performance at high anodic biases. Catalyst stability is an issue for both systems. The work presented here therefore expands our understanding of existing engineering strategies and informs future strategies for the design of efficient WO3 photoanodes.
Shock propagation into inhomogeneous media
Creators: name: Strachan, James D.
Publisher: name: University of British Columbia
Year: 2011

description: The propagation of a shock wave into a general inhomo-geneous flow field is studied. The equations for the shock velocity through such a region are developed in a general manner. A consequence of these equations is the development of the shock wave as a probe into unknown flow fields. The shock velocity is measured and the initial parameters ahead of the shock are calculated. The unique advantage of the shock probe is that it does not perturb the gas ahead of the front. An experimental application is described in which the shock probe is used to analyze the unknown flow field created by a constricted arc light source. The flow field is subsequently identified as a radiation front at the Chapman-Jouguet point.