1,083 research outputs found
Correction: Rubin, J.L. Applications of a Particular Four-Dimensional Projective Geometry to Galactic Dynamics. Galaxies 2018, 6, 83
No full textThe author wishes to make the following corrections to this paper [1]: [...
A modal derivatives enhanced Rubin substructuring method for geometrically nonlinear multibody systems
No full textThis paper presents a novel model order reduction technique for 3D flexible multibody systems featuring nonlinear elastic behavior. We adopt the mean-axis floating frame approach in combination with an enhanced Rubin substructuring technique for the construction of the reduction basis. The standard Rubin reduction basis is augmented with the modal derivatives of both free-interface vibration modes and attachment modes to consider the bending–stretching coupling effects for each flexible body. The mean-axis frame generally yields relative displacements and rotations of smaller magnitude when compared to the one obtained by the nodal-fixed floating frame. This positively impacts the accuracy of the reduction basis. Also, when equipped with modal derivatives, the Rubin method better considers the geometric nonlinearities than the Craig–Bampton method, as it comprises vibration modes and modal derivatives featuring free motion of the interface. The nonlinear coupling between free-interface modes and attachment modes is also considered. Numerical tests confirm that the proposed method is more accurate than Craig–Bampton’s, a nodal fixed floating frame counterpart originally proposed in Wu and Tiso (Multibody Syst. Dyn. 36(4): 405–425, [2016]), and produces significant speed-ups. However, the offline cost is increased because the mean-axis formulation produces operators with decreased sparsity patterns.Dynamics of Micro and Nano SystemsComputational Design and Mechanic
Rubin-Stark elements and ideal class groups (Algebraic Number Theory and Related Topics 2013)
No full text"Algebraic Number Theory and Related Topics 2013". December 9～13, 2013. edited by Tadashi Ochiai, Takeshi Tsuji and Iwao Kimura. The papers presented in this volume of RIMS Kôkyûroku Bessatsu are in final form and refereed.This article is a survey of the Galois module structure of the class groups of number fields, and of their relation with the L-values. After we explain several classical results, e.g., the order of a character component of a class group, etc., we introduce the Rubin-Stark conjecture in Rubin [27], which asserts the existence of certain algebraic elements related to the L-values. We also explain some new properties of Rubin-Stark elements obtained in a joint work of the author with D. Burns and T. Sano [7], including the description of the Fitting ideals of class groups and certain cohomology groups. We also give several concrete examples
Fluorine-enhanced boron diffusion in germanium-preamorphized silicon
No full textSilicon wafers were preamorphized with 60 keV Ge+ or 70 keV Si+ at a dose of 1× 1015 atoms cm2. F+ was then implanted into some samples at 6 keV at doses ranging from 1× 1014 to 5× 1015 atoms cm2, followed by B+11 implants at 500 eV, 1× 1015 atoms cm2. Secondary-ion-mass spectrometry confirmed that fluorine enhances boron motion in germanium-preamorphized materials in the absence of annealing. The magnitude of boron diffusion scales with increasing fluorine dose. Boron motion in as-implanted samples occurs when fluorine is concentrated above 1× 1020 atoms cm3. Boron atoms are mobile in as-implanted, amorphous material at concentrations up to 1× 1019 atoms cm3. Fluorine directly influences boron motion only prior to activation annealing. During the solid-phase epitaxial regrowth process, fluorine does not directly influence boron motion, it simply alters the recrystallization rate of the silicon substrate. Boron atoms can diffuse in germanium-amorphized silicon during recrystallization at elevated temperatures without the assistance of additional dopants. Mobile boron concentrations up to 1× 1020 atoms cm3 are observed during annealing of germanium-preamorphized wafers. © 2005 American Institute of Physics
Shifting ground: Can community development loan funds continue to serve the neediest borrowers?
No full textCommunity development financial institutions (CDFIs) are designed to improve economic conditions for low-income individuals and communities by providing a range of financial products and services that often are not available from mainstream lenders and financiers. ; Part I of this paper reviews CDLF origins, structures, and current activities. Part II discusses the field’s historic sources of subsidized capital and why they have shrunk. Part III reviews potential new sources of capital and the organizational ways that CDLFs are responding to their changed environment. The paper concludes with recommendations for CDLFs, funders, and policy makers.Community development ; Loans
MANOVA modelling of a chiropractic longitudinal study using multiple imputation
No full textThe purpose of this report is to present the detailed statistical analysis of a randomised, placebo-controlled trial comparing two different treatment modalities to an intervention of no known benefit for people with acute or subacute thoracic spine pain.
The therapy arms consist of Spinal Manipulative Therapy (SMT) and Graston Technique (GT) and the placebo is a non-functional ultrasound. A placebo group was utilised because at present there are no proven treatments for non-specific thoracic pain. This trial is registered with the Australia and New Zealand Clinical Trials Registry. Ethics approval has been granted by Murdoch University Human Research and Ethics Committee, number 2007/274.
The aim of this three arm trial was to test the efficacy of SMT and GT as independent modalities compared to detuned ultrasound for the outcomes of pain and disability. The latter were measured using the Visual Analogue Scale (VAS) and a modified Oswestry Back Pain Disability Index. The study was conducted at the Murdoch University Chiropractic student clinic in Perth, Australia, and the protocol published in Crothers et al (2008).
In this report, Section 2 provides an initial exploratory analysis of the data, Section 3 outlines the statistical models used in the final analysis, Section 4 defines these models in mathematical terms, Section 5 discusses the management of missing values via multiple imputation and Section 6 presents the results of the statistical modelling and hypothesis tests. The clinical study will be published in full elsewhere
Writing and the rights of reality: usurpation and potentiality in Derrida, Plato, Nietzsche, and Beckett
No full textThe thesis critically evaluates Jacques Derrida's conferral of the rights of reality on writing, focussing on his theory of an arche-text in light of the speculative nature of this theory. The theory is initially considered in the context of Derrida's elucidation of the usurpatory status of writing within the Platonic and Nietzschean texts. This consideration reveals an admission of writing's usurpatory status by both writers while at the same time demonstrating their awareness of the intrinsically speculative nature of this view, the significance of writing lying in its ability to exteriorise the radically indeterminate status of consciousness m relation to reality rather than its ability to displace consciousness or reality The analyses, therefore, not only bring the Derridean hypothesis of a repressive or phonocentric metaphysical episteme into question but also exhibit the historical and philosophical role of potentiality in relation to writing, writing's ultimate significance lying in its capacity to exteriorise our existence as a mode of potentiality. Accordingly, in the second half of the thesis the Derridean theory of writing is countered with a specifically Aristotelian theory of the text as it is exhibited in the prose of Samuel Beckett, an author whose significance lies in his close alignment with Derridean theory within contemporary criticism. It is demonstrated that this identification has obviated an awareness of the significance of potentiality within the Beckettian text, his work consequently being appraised in the previously neglected context of Aristotelian metaphysics
Iwasawa theory for modular forms at supersingular primes
No full textLet f=\sum a_nq^n be a normalised eigen-newform of weight k\ge2 and p an odd prime which does not divide the level of f. We study a reformulation of Kato's main conjecture for f over the Zp-cyclotomic extension of Q. In particular, we generalise Kobayashi's main conjecture on p-supersingular elliptic curves over Q with a_p=0, which asserts that Pollack's p-adic L-functions generate the characteristic ideals of some \pm-Selmer groups which are cotorsion over the Iwasawa algebra \Lambda=Zp[[Zp]].
We begin by studying the p-adic Hodge theory for the p-adic representation associated to f in the case when a_p=0. It allows us to give analogous definitions of Kobayashi's \pm-Coleman maps and \pm-Selmer groups. The Coleman maps are used to show that the Pontryagin duals of these new Selmer groups are torsion over \Lambda as in the elliptic curve case. As a consequence, we formulate a main conjecture stating that Pollack's p-adic L-functions generate their characteristic ideals. Similar to Kobayashi's works, we prove one inclusion of the main conjecture using an Euler system constructed by Kato.
We then prove the other inclusion of the main conjecture for CM modular forms, generalising works of Pollack and Rubin on CM elliptic curves. As a key step of the proof, we generalise the reciprocity law of Coates-Wiles and Rubin.
Next, we study Wach modules associated to positive crystalline p-adic representations in general and generalise the construction of the Coleman maps. By applying this to modular forms with much more general a_p, we define two Coleman maps and decompose the classical p-adic L functions of f into linear combinations of two power series of bounded coefficients generalising works of Pollack (in the case a_p=0) and Sprung (when f corresponds to an elliptic curve over Q with a_p\ne0). Once again, this leads to a reformulation of Kato's main conjecture involving cotorsion Selmer groups and p-adic L-functions of bounded coefficients. One inclusion of this new main conjecture is proved in the same way as the a_p=0 case.
Finally, we explain how the \pm-Coleman maps can be extended to Lubin-Tate extensions of height 1 in place of the Zp-cyclotomic extension. This generalises works of Iovita and Pollack for elliptic curves over Q
Relativistic Localizing Processes Bespeak an Inevitable Projective Geometry of Spacetime
No full textWork presented at the "5th Winter Workshop on Non-Perturbative Quantum Field Theory," (WWNPQFT) 22--24 March 2017, Institut du Non-Linéaire de Nice, Valbonne (France). Accepted for publication in the special issue "Nonperturbative Approaches in Field Theory," (Eds: R. Hofmann, T. Grandou) of "Advances in High Energy Physics" review.Surprisingly, the issue of events localization in spacetime is poorly understood and a fortiori realized even in the context of Einstein’s relativity. Accordingly, a comparison between observational data and theoretical expectations might then be strongly compromised. In the present paper, we give the principles of relativistic localizing systems so as to bypass this issue. Such systems will allow to locate users endowed with receivers and, in addition, to localize any spacetime event. These localizing systems are made up of relativistic auto-locating positioning sub-systems supplemented by an extra satellite. They indicate that spacetime must be supplied everywhere with an unexpected local four dimensional projective structure besides the well-known three dimensional relativistic projective one. As a result, the spacetime manifold can be seen as a generalized Cartan space modeled on a four dimensional real projective space, i.e., a spacetime with both a local four dimensional projective structure and a compatible (pseudo-)Riemannian structure. Localization protocols are presented in details, while possible applications to astrophysics are also considered
Applications d'une géométrie projective quadri-dimensionnelle particulière à la dynamique galactique
No full textPublished 3 August 2018 in the "Galaxies" journal (http://www.mdpi.com/journal/galaxies), Vol.6, Iss. 3 (Sept. 2018).International audienceRelativistic location systems that extend relativistic positioning systems show that pseudo-Riemannian space-time geometry is somehow encompassed in a particular four-dimensional projective geometry. The resulting geometric structure is then that of a generalized Cartan space (also called Cartan connection space) with projective connection. The result is that locally non-linear actions of projective groups via homographies systematically induce the existence of a particular space-time foliation independent of any space-time dynamics or solutions of Einstein's equations for example. In this article, we present the consequences of these projective group actions and this foliation. In particular, it is shown that the particular geometric structure due to this foliation is similar from a certain point of view to that of a black hole but not necessarily based on the existence of singularities. We also present modified Newton's laws invariant with respect to the homographic transformations induced by this projective geometry. Consequences on galactic dynamics are discussed and fits of galactic rotational velocity curves based on these modificationswhich are independent of any MOND or dark matter theories are presented
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