Exploiting total internal reflection geometry for efficient optical modulation of terahertz light
Directory of Open Access Journals (Sweden)
Xudong Liu
2016-10-01
Full Text Available Efficient methods to modulate terahertz (THz light are essential for realizing rapid THz imaging and communication applications. Here we report a novel THz modulator which utilizes the evanescent wave in a total internal reflection setup coupled with a conductive interface to enhance the attenuation efficiency of THz light. This approach makes it possible to achieve close to 100% modulation with a small interface conductivity of 12 mS. The frequency dependence of this technique is linked to the optical properties of the materials: a material with close to frequency independent conductivity that is also controllable will result in an achromatic modulation response, and the device performance can be optimized further by tuning the internal reflection angle. In this work, we focus on applying the technique in the terahertz frequency range. Using an LED array with a pump intensity of 475 mW/cm2 to produce carriers in a silicon wafer, we have achieved a modulation depth of up to 99.9% in a broad frequency range of 0.1 THz–0.8 THz. The required pumping power for the generation of the required free carriers is low because the sheet conductivity needed is far less than required for traditional transmission techniques. Consequently, the device can be modulated by an LED making it a very practical, low cost, and scalable solution for THz modulation.
Liu, Xudong; Chen, Xuequan; Parrott, Edward P. J.; Han, Chunrui; Humbert, Georges; Crunteanu, Aurelian; Pickwell-MacPherson, Emma
2018-05-01
Active broadband terahertz (THz) polarization manipulation devices are challenging to realize, but also of great demand in broadband terahertz systems. Vanadium dioxide (VO2) shows a promising phase transition for active control of THz waves and provides broadband polarization characteristics when integrated within grating-type structures. We creatively combine a VO2-based grating structure with a total internal reflection (TIR) geometry providing a novel interaction mechanism between the electromagnetic waves and the device, to realize a powerful active broadband THz polarization-controlling device. The device is based on a Si-substrate coated with a VO2 layer and a metal grating structure on top, attached to a prism for generating the TIR condition on the Si-VO2-grating interface. The grating is connected to electrodes for electrically switching the VO2 between its insulating and conducting phases. By properly selecting the incident angle of the THz waves, the grating direction, and the incident polarization state, we first achieved a broadband intensity modulator under a fused silica prism with an average modulation depth of 99.75% in the 0.2-1.1 THz region. Additionally, we realized an active ultra-broadband quarter-wave converter under a Si prism that can be switched between a 45° linear rotator and a quarter wave converter in the 0.8-1.5 THz region. This is the first demonstration of an active quarter-wave converter with ultra-broad bandwidth performance. Our work shows a highly flexible and multifunctional polarization-controlling device for broadband THz applications.
Second International workshop Geometry and Symbolic Computation
Walczak, Paweł; Geometry and its Applications
2014-01-01
This volume has been divided into two parts: Geometry and Applications. The geometry portion of the book relates primarily to geometric flows, laminations, integral formulae, geometry of vector fields on Lie groups, and osculation; the articles in the applications portion concern some particular problems of the theory of dynamical systems, including mathematical problems of liquid flows and a study of cycles for non-dynamical systems. This Work is based on the second international workshop entitled "Geometry and Symbolic Computations," held on May 15-18, 2013 at the University of Haifa and is dedicated to modeling (using symbolic calculations) in differential geometry and its applications in fields such as computer science, tomography, and mechanics. It is intended to create a forum for students and researchers in pure and applied geometry to promote discussion of modern state-of-the-art in geometric modeling using symbolic programs such as Maple™ and Mathematica®, as well as presentation of new results. ...
VIII International Meeting on Lorentzian Geometry
Flores, José; Palomo, Francisco; GeLoMa 2016; Lorentzian geometry and related topics
2017-01-01
This volume contains a collection of research papers and useful surveys by experts in the field which provide a representative picture of the current status of this fascinating area. Based on contributions from the VIII International Meeting on Lorentzian Geometry, held at the University of Málaga, Spain, this volume covers topics such as distinguished (maximal, trapped, null, spacelike, constant mean curvature, umbilical...) submanifolds, causal completion of spacetimes, stationary regions and horizons in spacetimes, solitons in semi-Riemannian manifolds, relation between Lorentzian and Finslerian geometries and the oscillator spacetime. In the last decades Lorentzian geometry has experienced a significant impulse, which has transformed it from just a mathematical tool for general relativity to a consolidated branch of differential geometry, interesting in and of itself. Nowadays, this field provides a framework where many different mathematical techniques arise with applications to multiple parts of mathem...
External and internal geometry of European adults.
Bertrand, Samuel; Skalli, Wafa; Delacherie, Laurent; Bonneau, Dominique; Kalifa, Gabriel; Mitton, David
2006-12-15
The primary objective of the study was to bring a deeper knowledge of the human anthropometry, investigating the external and internal body geometry of small women, mid-sized men and tall men. Sixty-four healthy European adults were recruited. External measurements were performed using classical anthropometric instruments. Internal measurements of the trunk bones were performed using a stereo-radiographic 3D reconstruction technique. Besides the original procedure presented in this paper for performing in vivo geometrical data acquisition on numerous volunteers, this study provides an extensive description of both external and internal (trunk skeleton) human body geometry for three morphotypes. Moreover, this study proposes a global external and internal geometrical description of 5th female 50th male and 95th male percentile subjects. This study resulted in a unique geometrical database enabling improvement for numerical models of the human body for crash test simulation and offering numerous possibilities in the anthropometry field.
International conference on Algebraic and Complex Geometry
Kloosterman, Remke; Schütt, Matthias
2014-01-01
Several important aspects of moduli spaces and irreducible holomorphic symplectic manifolds were highlighted at the conference “Algebraic and Complex Geometry” held September 2012 in Hannover, Germany. These two subjects of recent ongoing progress belong to the most spectacular developments in Algebraic and Complex Geometry. Irreducible symplectic manifolds are of interest to algebraic and differential geometers alike, behaving similar to K3 surfaces and abelian varieties in certain ways, but being by far less well-understood. Moduli spaces, on the other hand, have been a rich source of open questions and discoveries for decades and still continue to be a hot topic in itself as well as with its interplay with neighbouring fields such as arithmetic geometry and string theory. Beyond the above focal topics this volume reflects the broad diversity of lectures at the conference and comprises 11 papers on current research from different areas of algebraic and complex geometry sorted in alphabetic order by the ...
Studies of the Reflection, Refraction and Internal Reflection of Light
Lanchester, P. C.
2014-01-01
An inexpensive apparatus and associated experiments are described for studying the basic laws of reflection and refraction of light at an air-glass interface, and multiple internal reflections within a glass block. In order to motivate students and encourage their active participation, a novel technique is described for determining the refractive…
Total internal reflection effect on gyrotropic interface
Glushchenko, Alexander G.; Glushchenko, Eugene P.; Zhukov, Sergey V.
2018-02-01
This article considers the physical features of total internal reflection at gyrotropic and isotropic interfaces for two cases: electrical gyrotropy (plasma) and magnetic gyrotropy (ferrite). It is shown that the plasma magnetization may lead to the formation of the total internal reflection effect, which does not occur in isotropic plasma. The threshold values of the magnetic field, which are necessary for the total internal reflection effect, are determined. The total internal reflection effect on a ferrite-dielectric interface for waves emanating from different angles is observed in various frequency ranges and magnetization fields. The study points out the possibility of changing the total internal reflection angle value in large limits due to a change in the external magnetic field magnitude. The calculation results of the total internal reflection angle dependence on the external magnetic field magnitude are presented. The formulas are elaborated for calculating the total internal reflection angles of different interfaces for gyrotropic and isotropic media. The generalized formulas are defined for calculating the Doppler effect in the gyrotropic media. The study demonstrates how the velocity of the media interface affects the limiting angle of total internal refection.
On ''conformal spinor geometry'': An attempt to ''understand'' internal symmetry
International Nuclear Information System (INIS)
Budinich, P.
1982-01-01
The natural homomorphism of pure spinors corresponding to a given Clifford algebra Csub(2n) to polarized isotropic n-planes of complex Euclidean space Esub(2n)sup(c) is taken as a starting point for the construction of a geometry called spinor geometry where pure spinors are the only elements out of which all tensors have to be constructed (analytically as bilinear polynomials of the components of a pure spinor). C 4 and C 6 spinor geometry are analyzed, but it seems that C 8 spinor geometry is necessary to construct Minkowski space Msup(3,1). C 6 spinor field equations give rise in Minkowski space to a pair of Dirac equations (for conformal semispinors) presenting an su(2) internal symmetry algebra. Mass is generated by breaking spontaneously the original O(4,2) symmetry of the spinor equation. (author)
On ''conformal spinor geometry'': An attempt to ''understand'' internal symmetry
International Nuclear Information System (INIS)
Budinich, P.
1981-09-01
The natural homomorphism of pure spinors corresponding to a given Clifford algebra Csub(2n) to polarized isotropic n-planes of complex Euclidean space Esub(2n)sup(c) is taken as a starting point for the construction of a geometry called spinor geometry where pure spinors are the only elements out of which all tensors have to be constructed (analytically as bilinear polynomia of the components of a pure spinor). C 4 and C 6 spinor geometry are analyzed but it seems that C 8 spinor geometry is necessary to construct Minkowski space Msup(3,1). C 6 spinor field equations give rise in Minkowski space to a pair of Dirac equations (for conformal semispinors) presenting an SU(2) internal symmetry algebra. Mass is generated by spontaneously breaking the original O(4,2) symmetry of the spinor equation. (author)
3rd International Conference on Computational Mathematics and Computational Geometry
Ravindran, Anton
2016-01-01
This volume presents original research contributed to the 3rd Annual International Conference on Computational Mathematics and Computational Geometry (CMCGS 2014), organized and administered by Global Science and Technology Forum (GSTF). Computational Mathematics and Computational Geometry are closely related subjects, but are often studied by separate communities and published in different venues. This volume is unique in its combination of these topics. After the conference, which took place in Singapore, selected contributions chosen for this volume and peer-reviewed. The section on Computational Mathematics contains papers that are concerned with developing new and efficient numerical algorithms for mathematical sciences or scientific computing. They also cover analysis of such algorithms to assess accuracy and reliability. The parts of this project that are related to Computational Geometry aim to develop effective and efficient algorithms for geometrical applications such as representation and computati...
Energy Technology Data Exchange (ETDEWEB)
Du, Jiangtao; Sharples, Steve [School of Architecture, University of Sheffield, Crookesmoor Building, Conduit Road, Sheffield S10 1FL (United Kingdom)
2010-07-15
This study investigated the impacts of different diffuse reflectance distributions and well geometries on vertical daylight factors and vertical internally reflected components in atria. Two forms of reflectance distribution patterns of wall surface were examined: horizontal and vertical reflectance band variation. The square atrium models studied have a broader WI range of 0.25-2.0, which represent shallow, medium and high atria. Radiance, a powerful package based on backward ray tracing technique, was used for the simulations of vertical daylight levels. The results show that different reflectance distributions of square atrium walls do have an impact on the vertical daylight factors and vertical internally reflected components under overcast sky condition. The impact relates to the orientation of the band with different reflectance distributions on the wall. Compared with the vertical band surface, the horizontal band surface has a much more complicated effect. The horizontal distributions of the reflectances significantly affects the vertical daylight levels at the locations more than 30% atrium height on the wall. For an atrium with a height more than 1/2 the width, the effect tends to increase with the increasing well index. The vertical distributions of the reflectance, nevertheless, do not substantially take effect on the vertical daylight levels in atria except for some special reflectance distribution patterns. (author)
Sossinsky, A B
2012-01-01
The book is an innovative modern exposition of geometry, or rather, of geometries; it is the first textbook in which Felix Klein's Erlangen Program (the action of transformation groups) is systematically used as the basis for defining various geometries. The course of study presented is dedicated to the proposition that all geometries are created equal--although some, of course, remain more equal than others. The author concentrates on several of the more distinguished and beautiful ones, which include what he terms "toy geometries", the geometries of Platonic bodies, discrete geometries, and classical continuous geometries. The text is based on first-year semester course lectures delivered at the Independent University of Moscow in 2003 and 2006. It is by no means a formal algebraic or analytic treatment of geometric topics, but rather, a highly visual exposition containing upwards of 200 illustrations. The reader is expected to possess a familiarity with elementary Euclidean geometry, albeit those lacking t...
Indian Academy of Sciences (India)
. In the previous article we looked at the origins of synthetic and analytic geometry. More practical minded people, the builders and navigators, were studying two other aspects of geometry- trigonometry and integral calculus. These are actually ...
Prasolov, V V
2015-01-01
This book provides a systematic introduction to various geometries, including Euclidean, affine, projective, spherical, and hyperbolic geometries. Also included is a chapter on infinite-dimensional generalizations of Euclidean and affine geometries. A uniform approach to different geometries, based on Klein's Erlangen Program is suggested, and similarities of various phenomena in all geometries are traced. An important notion of duality of geometric objects is highlighted throughout the book. The authors also include a detailed presentation of the theory of conics and quadrics, including the theory of conics for non-Euclidean geometries. The book contains many beautiful geometric facts and has plenty of problems, most of them with solutions, which nicely supplement the main text. With more than 150 figures illustrating the arguments, the book can be recommended as a textbook for undergraduate and graduate-level courses in geometry.
Frustrated Total Internal Reflection: A Simple Application and Demonstration.
Zanella, F. P.; Magalhaes, D. V.; Oliveira, M. M.; Bianchi, R. F.; Misoguti, L.; Mendonca, C. R.
2003-01-01
Describes the total internal reflection process that occurs when the internal angle of incidence is equal to or greater than the critical angle. Presents a demonstration of the effect of frustrated total internal reflection (FTIR). (YDS)
Total internal reflection tomography of small objects
International Nuclear Information System (INIS)
Chen Xudong
2008-01-01
The multiple signal classification (MUSIC) imaging method is applied to determine the locations of a collection of small anisotropic spherical scatterers in the framework of the total internal reflection tomography. Multiple scattering between scatterers is considered and the inverse scattering problem is nonlinear, which, however, is solved by the proposed fast analytical approach where no associated forward problem is iteratively evaluated. The paper also discusses the role of the polarization of incidence waves, the incidence angle, the separation of scatterers from the surface of the substrate, and the level of noise on the resolution of imaging.
International Nuclear Information System (INIS)
Falkenberg, G.; Pepponi, G.; Streli, C.; Wobrauschek, P.
2003-01-01
X-ray absorption fine structure (XAFS) experiments in fluorescence mode have been performed in total reflection excitation geometry and conventional 45 deg. /45 deg. excitation/detection geometry for comparison. The experimental results have shown that XAFS measurements are feasible under normal total reflection X-ray fluorescence (TXRF) conditions, i.e. on droplet samples, with excitation in grazing incidence and using a TXRF experimental chamber. The application of the total reflection excitation geometry for XAFS measurements increases the sensitivity compared to the conventional geometry leading to lower accessible concentration ranges. However, XAFS under total reflection excitation condition fails for highly concentrated samples because of the self-absorption effect
Parsons, L. C.; Andrews, G. T.
2012-09-01
Pseudo-reflection geometry Brillouin spectroscopy can be used to probe acoustic wave dispersion approximately along the surface normal of a material system while avoiding the difficulties associated with specularly reflected light encountered in an ideal reflection configuration. As an example of its application, we show analytically that it can be used to determine both the refractive index and bulk acoustic mode velocities of optically-isotropic non-metallic materials and confirm the utility of the approach via a series of experiments on fused quartz, gallium phosphide, water, and porous silicon films.
Pedoe, Dan
1988-01-01
""A lucid and masterly survey."" - Mathematics Gazette Professor Pedoe is widely known as a fine teacher and a fine geometer. His abilities in both areas are clearly evident in this self-contained, well-written, and lucid introduction to the scope and methods of elementary geometry. It covers the geometry usually included in undergraduate courses in mathematics, except for the theory of convex sets. Based on a course given by the author for several years at the University of Minnesota, the main purpose of the book is to increase geometrical, and therefore mathematical, understanding and to he
Variation of MODIS reflectance and vegetation indices with viewing geometry and soybean development.
Breunig, Fábio M; Galvão, Lênio S; Formaggio, Antônio R; Epiphanio, José C N
2012-06-01
Directional effects introduce a variability in reflectance and vegetation index determination, especially when large field-of-view sensors are used (e.g., Moderate Resolution Imaging Spectroradiometer - MODIS). In this study, we evaluated directional effects on MODIS reflectance and four vegetation indices (Normalized Difference Vegetation Index - NDVI; Enhanced Vegetation Index - EVI; Normalized Difference Water Index - NDWI(1640) and NDWI(2120)) with the soybean development in two growing seasons (2004-2005 and 2005-2006). To keep the reproductive stage for a given cultivar as a constant factor while varying viewing geometry, pairs of images obtained in close dates and opposite view angles were analyzed. By using a non-parametric statistics with bootstrapping and by normalizing these indices for angular differences among viewing directions, their sensitivities to directional effects were studied. Results showed that the variation in MODIS reflectance between consecutive phenological stages was generally smaller than that resultant from viewing geometry for closed canopies. The contrary was observed for incomplete canopies. The reflectance of the first seven MODIS bands was higher in the backscattering. Except for the EVI, the other vegetation indices had larger values in the forward scattering direction. Directional effects decreased with canopy closure. The NDVI was lesser affected by directional effects than the other indices, presenting the smallest differences between viewing directions for fixed phenological stages.
International Nuclear Information System (INIS)
Kaufman, A.N.; Brizard, A.J.; Cook, D.R.
1993-01-01
The analysis of the minority-ion gyroresonant heating process by a magnetosonic wave in a general magnetic field geometry with one ignorable spatial coordinate can be divided into several steps, each defined in terms of a precise mathematical problem to be solved. In this work, the authors focus their attention on the magnetosonic wave reflection problem in axisymmetric tokamak geometry; the conversion and absorption of the minority-ion gyroresonant ballistic waves are treated elsewhere. In contrast to their previous work, they employ a kinetic model based on the perturbation generating function S for the gyroresonant minority-ions. The bulk plasma response is represented by the perturbation magnetic vector potential A, corresponding to a shielded magnetosonic wave. The set of coupled equations for S and A can be derived from an action principle, which can also be used to derive explicit wave-action conservation laws in ray phase space. The reflection problem is solved in ray phase space by considering three separate steps. In the first step, the incident magnetosonic ray propagates towards the first linear mode conversion region, where action is transferred to the minority-ion gyroresonant ballistic waves. In the second step, the continuum of excited gyroresonant ballistic rays propagate towards the second linear mode conversion region. In the third step, the reflected magnetosonic wave field is excited by linear mode conversion from the minority gyroresonant ballistic rays
X-Ray Topography of the Subsurface Crystal Layers in the Skew Asymmetric Reflection Geometry
Directory of Open Access Journals (Sweden)
Swiątek Z.
2016-12-01
Full Text Available The technique of X ray topography with the asymmetric reflection geometry of X-ray diffraction presented in this paper as useful tool for structural characterization of materials, particularly, epitaxial thin films and semiconductor multi-layered crystal systems used for the optoelectronic devices. New possibilities of this technique for a layer-by-layer visualization of structural changes in the subsurface crystal layers are demonstrated for semiconductors after various types of surface treatment, such as chemical etching, laser irradiation and ion implantation.
Water-Reflected 233U Uranyl Nitrate Solutions in Simple Geometry
International Nuclear Information System (INIS)
Elam, K.R.
2001-01-01
A number of critical experiments involving 233 U were performed in the Oak Ridge National Laboratory Building 9213 Critical Experiments Facility during the years 1952 and 1953. These experiments, reported in Reference 1, were directed toward determining bounding values for the minimum critical mass, minimum critical volume, and maximum safe pipe size of water-moderated solutions of 233 U. Additional information on the critical experiments was found in the experimental logbooks. Two experiments utilizing uranyl nitrate (UO 2 (NO 3 ) 2 ) solutions in simple geometry are evaluated in this report. Experiment 37 is in a 10.4-inch diameter sphere, and Experiment 39 is in a 10-inch diameter cylinder. The 233 U concentration ranges from 49 to 62 g 233 U/l. Both experiments were reflected by at least 6 inches of water in all directions. Paraffin-reflected uranyl nitrate experiments, also reported in Reference 1, are evaluated elsewhere. Experiments with smaller paraffin reflected 5-, 6-, and 7.5-inch diameter cylinders are evaluated in U233-SOL-THERM-004. Experiments with paraffin reflected 8-, 8.5-, 9-, 10-, and 12-inch diameter cylinders are evaluated in U233-SOL-THERM-002. Later experiments with highly-enriched 235 U uranyl fluoride solution in the same 10.4-inch diameter sphere are reported in HEU-SOL-THERM-010. Both experiments were judged acceptable for use as criticality-safety benchmark experiments
Forensic applications of microscopical infrared internal reflection spectroscopy
Tungol, Mary W.; Bartick, Edward G.; Reffner, John A.
1994-01-01
Applications of microscopical infrared internal reflection spectroscopy in forensic science are discussed. Internal reflection spectra of single fibers, hairs, paint chips, vehicle rubber bumpers, photocopy toners, carbon copies, writing ink on paper, lipstick on tissue, black electrical tape, and other types of forensic evidence have been obtained. The technique is convenient, non-destructive, and may permit smeared materials to be analyzed in situ.
Terahertz pulse imaging in reflection geometry of human skin cancer and skin tissue
International Nuclear Information System (INIS)
Woodward, Ruth M; Cole, Bryan E; Wallace, Vincent P; Pye, Richard J; Arnone, Donald D; Linfield, Edmund H; Pepper, Michael
2002-01-01
We demonstrate the application of terahertz pulse imaging (TPI) in reflection geometry for the study of skin tissue and related cancers both in vitro and in vivo. The sensitivity of terahertz radiation to polar molecules, such as water, makes TPI suitable for studying the hydration levels in the skin and the determination of the lateral spread of skin cancer pre-operatively. By studying the terahertz pulse shape in the time domain we have been able to differentiate between diseased and normal tissue for the study of basal cell carcinoma (BCC). Basal cell carcinoma has shown a positive terahertz contrast, and inflammation and scar tissue a negative terahertz contrast compared to normal tissue. In vivo measurements on the stratum corneum have enabled visualization of the stratum corneum-epidermis interface and the study of skin hydration levels. These results demonstrate the potential of terahertz pulse imaging for the study of skin tissue and its related disorders, both in vitro and in vivo
RefleX: X-ray absorption and reflection in active galactic nuclei for arbitrary geometries
Paltani, S.; Ricci, C.
2017-11-01
Reprocessed X-ray radiation carries important information about the structure and physical characteristics of the material surrounding the supermassive black hole (SMBH) in active galactic nuclei (AGN). We report here on a newly developed simulation platform, RefleX, which allows to reproduce absorption and reflection by quasi-arbitrary geometries. We show here the reliability of our approach by comparing the results of our simulations with existing spectral models such as pexrav, MYTorus and BNTorus. RefleX implements both Compton scattering on free electrons and Rayleigh scattering and Compton scattering on bound electrons. We show the effect of bound-electron corrections on a torus geometry simulated like in MYTorus. We release with this paper the RefleX executable, as well as RXTorus, a model that assumes absorption and reflection from a torus with a varying ratio of the minor to major axis of the torus. To allow major flexibility RXTorus is also distributed in three components: absorbed primary emission, scattered radiation and fluorescent lines. RXTorus is provided for different values of the abundance, and with (atomic configuration) or without (free-electron configuration) taking into account Rayleigh scattering and bound electrons. We apply the RXTorus model in both configurations on the XMM-Newton and NuSTAR spectrum of the Compton-thick AGN NGC 424 and find that the models are able to reproduce very well the observations, but that the assumption on the bound or free state of the electrons has significant consequences on the fit parameters. RefleX executable, user manual and example models are available at http://www.astro.unige.ch/reflex. A copy of the RefleX executable is also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/607/A31
Variation of MODIS reflectance and vegetation indices with viewing geometry and soybean development
Directory of Open Access Journals (Sweden)
Fábio M. Breunig
2012-06-01
Full Text Available Directional effects introduce a variability in reflectance and vegetation index determination, especially when large field-of-view sensors are used (e.g., Moderate Resolution Imaging Spectroradiometer - MODIS. In this study, we evaluated directional effects on MODIS reflectance and four vegetation indices (Normalized Difference Vegetation Index - NDVI; Enhanced Vegetation Index - EVI; Normalized Difference Water Index - NDWI1640 and NDWI2120 with the soybean development in two growing seasons (2004-2005 and 2005-2006. To keep the reproductive stage for a given cultivar as a constant factor while varying viewing geometry, pairs of images obtained in close dates and opposite view angles were analyzed. By using a non-parametric statistics with bootstrapping and by normalizing these indices for angular differences among viewing directions, their sensitivities to directional effects were studied. Results showed that the variation in MODIS reflectance between consecutive phenological stages was generally smaller than that resultant from viewing geometry for closed canopies. The contrary was observed for incomplete canopies. The reflectance of the first seven MODIS bands was higher in the backscattering. Except for the EVI, the other vegetation indices had larger values in the forward scattering direction. Directional effects decreased with canopy closure. The NDVI was lesser affected by directional effects than the other indices, presenting the smallest differences between viewing directions for fixed phenological stages.Efeitos direcionais introduzem variabilidade na reflectância e na determinação de índices de vegetação, especialmente quando sensores de amplo campo de visada são usados (p.ex., Moderate Resolution Imaging Spectroradiometer - MODIS. Neste estudo, nós avaliamos os efeitos direcionais sobre a reflectância e quatro índices de vegetação (Normalized Difference Vegetation Index - NDVI; Enhanced Vegetation Index - EVI; Normalized
Reflections on Dead Theory in International Relations
Thakur, Vineet
2016-01-01
In this short autobiographical essay, I trace my journey in the discipline of International Relations. While entering the discipline, I, along with a host of my classmates, were enamoured by the exciting possibilities of thinking theoretically. Almost a decade later, those promises look bleak. From the perspective of a student in the discipline, I…
REFLECTIONS ON PRODUCTION INTERNALIZATION AND ITS INTERNATIONAL TRADE IMPLICATIONS
Directory of Open Access Journals (Sweden)
CLIPA RALUCA IRINA
2014-06-01
Full Text Available Vertically-integrated multinational companies place the different stages of production and marketing chain in different countries, looking for advantages such as low production costs, lower taxes, abundant resources and so on, while benefiting from the advantages of economies of scale, control of supplies or outlets. In fact, this vertical integration of multinational companies has led to the expansion of intra-firm trade and "internalized" operations, thus creating their own markets for the vertically-integrated production. Internationally active firms operate in a way that replaces the different functions of an open market with internal transactions, i.e. intra-firm transactions, whenever internal transaction costs are lower than the open-market ones. The direct consequence over international trade is the increase of intra-firm share of trade flows to one third of world trade, those companies making a suppression of international market segments that act in favour of an internal market. The creation of a multinational market and the enhancement of intra-firm trade have profound quantitative and qualitative implications on the composition, geographic orientation and dynamics of international trade. This paper deals with the issue of production internalization, with an overview of the main contributions made to the theory of internalization, while tackling its relative dimension. However, we intend to highlight the implications of this phenomenon on international trade. The work methodology falls within the range of qualitative approaches: logical argumentation, critical theoretical analysis.
Nonimaging light concentration using total internal reflection films.
Ouellette, G; Waltham, C E; Drees, R M; Poon, A; Schubank, R; Whitehead, L A
1992-05-01
We present a method of fabricating nonimaging light concentrators from total internal reflection film. A prototype has been made and tested and found to operate in agreement with predictions of ray-tracing codes. The performance of the prototype is comparable with that of concentrators made from specular reflecting materials.
Reflections on International Certified Nursing Assistants.
Shaw, Penelope Ann
2017-01-01
The author, a former university faculty member who taught English to speakers of other languages and now a nursing home resident, shares her observations about how English language proficiency, culture, and religious differences affect her care. She provides examples of communication challenges that can be annoying or cause harm, her coping strategies, and reasons many certified nursing assistants might never be fully fluent in English. She explains how international certified nursing assistants can benefit residents because of skills developed by family-centered care in their countries of origin. She also discusses related issues-the importance of being culturally competent about U.S. culture. She points out how religiousness not only affects residents but is a buffer for staff against the stress of physically and emotionally demanding low-wage work. Overall, the author likes receiving care from individuals from other countries, finding reward in comparing how her personal struggle with illness and paralysis resonates with the trauma of migration and how learning firsthand about varying beliefs and attitudes clarifies her identity and place in world history.
Critical experiments on single-unit spherical plutonium geometries reflected and moderated by oil
International Nuclear Information System (INIS)
Rothe, R.E.
1997-05-01
Experimental critical configurations are reported for several dozen spherical and hemispherical single-unit assemblies of plutonium metal. Most were solid but many were hollow-centered, thick, shell-like geometries. All were constructed of nested plutonium (mostly 2139 Pu) metal hemispherical shells. Three kinds of critical configurations are reported. Two required interpolation and/or extrapolation of data to obtain the critical mass because reflector conditions were essentially infinite. The first finds the plutonium essentially fully reflected by a hydrogen-rich oil; the second is essentially unreflected. The third kind reports the critical oil reflector height above a large plutonium metal assembly of accurately known mass (no interpolation required) when that mass was too great to permit full oil reflection. Some configurations had thicknesses of mild steel just outside the plutonium metal, separating it from the oil. These experiments were performed at the Rocky Flats Critical Mass Laboratory in the late 1960s. They have not been published in a form suitable for benchmark-quality comparisons against state-of-the-art computational techniques until this paper. The age of the data and other factors lead to some difficulty in reconstructing aspects of the program and may, in turn, decrease confidence in certain details. Whenever this is true, the point is acknowledged. The plutonium metal was alpha-phase 239 Pu containing 5.9 wt-% 240 Pu. All assemblies were formed by nesting 1.667-mm-thick (nominal) bare plutonium metal hemispherical shells, also called hemishells, until the desired configuration was achieved. Very small tolerance gaps machined into radial dimensions reduced the effective density a small amount in all cases. Steel components were also nested hemispherical shells; but these were nominally 3.333-mm thick. Oil was used as the reflector because of its chemical compatibility with plutonium metal
Shin, Sunghwan; Kang, Hani; Kim, Jun Soo; Kang, Heon
2014-11-26
We investigated the phase transformations of amorphous solid acetone under confined geometry by preparing acetone films trapped in amorphous solid water (ASW) or CCl4. Reflection absorption infrared spectroscopy (RAIRS) and temperature-programmed desorption (TPD) were used to monitor the phase changes of the acetone sample with increasing temperature. An acetone film trapped in ASW shows an abrupt change in the RAIRS features of the acetone vibrational bands during heating from 80 to 100 K, which indicates the transformation of amorphous solid acetone to a molecularly aligned crystalline phase. Further heating of the sample to 140 K produces an isotropic solid phase, and eventually a fluid phase near 157 K, at which the acetone sample is probably trapped in a pressurized, superheated condition inside the ASW matrix. Inside a CCl4 matrix, amorphous solid acetone crystallizes into a different, isotropic structure at ca. 90 K. We propose that the molecularly aligned crystalline phase formed in ASW is created by heterogeneous nucleation at the acetone-water interface, with resultant crystal growth, whereas the isotropic crystalline phase in CCl4 is formed by homogeneous crystal growth starting from the bulk region of the acetone sample.
International Mindedness through the Looking Glass: Reflections on a Concept
Castro, Paloma; Lundgren, Ulla; Woodin, Jane
2015-01-01
The aim of this article is to report and reflect on a research project involving the conceptualization of the term "International Mindedness", which is used across a range of International Baccalaureate (IB) global and local contexts. The research process involved both a critical analysis of IB official documents and a literature review…
Harnessing Multiple Internal Reflections to Design Highly Absorptive Acoustic Metasurfaces
Shen, Chen; Cummer, Steven A.
2018-05-01
The rapid development of metasurfaces has enabled numerous intriguing applications with acoustically thin sheets. Here we report the theory and experimental realization of a nonresonant sound-absorbing strategy using metasurfaces by harnessing multiple internal reflections. We theoretically and numerically show that the higher-order diffraction of thin gradient-index metasurfaces is tied to multiple internal reflections inside the unit cells. Highly absorbing acoustic metasurfaces can be realized by enforcing multiple internal reflections together with a small amount of loss. A reflective gradient-index acoustic metasurface is designed based on the theory, and we further experimentally verify the performance using a three-dimensional printed prototype. Measurements show over 99% energy absorption at the peak frequency and a 95% energy absorption bandwidth of around 600 Hz. The proposed mechanism provides an alternative route for sound absorption without the necessity of high absorption of the individual unit cells.
A Method of Drusen Measurement Based on the Geometry of Fundus Reflectance
Directory of Open Access Journals (Sweden)
Barbazetto Irene
2003-04-01
Full Text Available Abstract Background The hallmarks of age-related macular degeneration, the leading cause of blindness in the developed world, are the subretinal deposits known as drusen. Drusen identification and measurement play a key role in clinical studies of this disease. Current manual methods of drusen measurement are laborious and subjective. Our purpose was to expedite clinical research with an accurate, reliable digital method. Methods An interactive semi-automated procedure was developed to level the macular background reflectance for the purpose of morphometric analysis of drusen. 12 color fundus photographs of patients with age-related macular degeneration and drusen were analyzed. After digitizing the photographs, the underlying background pattern in the green channel was leveled by an algorithm based on the elliptically concentric geometry of the reflectance in the normal macula: the gray scale values of all structures within defined elliptical boundaries were raised sequentially until a uniform background was obtained. Segmentation of drusen and area measurements in the central and middle subfields (1000 μm and 3000 μm diameters were performed by uniform thresholds. Two observers using this interactive semi-automated software measured each image digitally. The mean digital measurements were compared to independent stereo fundus gradings by two expert graders (stereo Grader 1 estimated the drusen percentage in each of the 24 regions as falling into one of four standard broad ranges; stereo Grader 2 estimated drusen percentages in 1% to 5% intervals. Results The mean digital area measurements had a median standard deviation of 1.9%. The mean digital area measurements agreed with stereo Grader 1 in 22/24 cases. The 95% limits of agreement between the mean digital area measurements and the more precise stereo gradings of Grader 2 were -6.4 % to +6.8 % in the central subfield and -6.0 % to +4.5 % in the middle subfield. The mean absolute
Total internal reflection and dynamic light scattering microscopy of gels
Gregor, Brian F.
Two different techniques which apply optical microscopy in novel ways to the study of biological systems and materials were built and applied to several samples. The first is a system for adapting the well-known technique of dynamic light scattering (DLS) to an optical microscope. This can detect and scatter light from very small volumes, as compared to standard DLS which studies light scattering from volumes 1000x larger. The small scattering volume also allows for the observation of nonergodic dynamics in appropriate samples. Porcine gastric mucin (PGM) forms a gel at low pH which lines the epithelial cell layer and acts as a protective barrier against the acidic stomach environment. The dynamics and microscopic viscosity of PGM at different pH levels is studied using polystyrene microspheres as tracer particles. The microscopic viscosity and microrheological properties of the commercial basement membrane Matrigel are also studied with this instrument. Matrigel is frequently used to culture cells and its properties remain poorly determined. Well-characterized and purely synthetic Matrigel substitutes will need to have the correct rheological and morphological characteristics. The second instrument designed and built is a microscope which uses an interferometry technique to achieve an improvement in resolution 2.5x better in one dimension than the Abbe diffraction limit. The technique is based upon the interference of the evanescent field generated on the surface of a prism by a laser in a total internal reflection geometry. The enhanced resolution is demonstrated with fluorescent samples. Additionally. Raman imaging microscopy is demonstrated using the evanescent field in resonant and non-resonant samples, although attempts at applying the enhanced resolution technique to the Raman images were ultimately unsuccessful. Applications of this instrument include high resolution imaging of cell membranes and macroscopic structures in gels and proteins. Finally, a third
International Nuclear Information System (INIS)
Chavda, L.K.
1978-01-01
Approximate analytic solutions to the self-similar equations of gas dynamics for a plasma, treated as an ideal gas with specific heat ratio γ=5/3 are obtained for the implosion and subsequent reflection of various types of shock sequences in spherical and cylindrical geometries. This is based on the lowest-order polynomial approximation in the reduced fluid velocity, for a suitable nonlinear function of the sound velocity and the fluid velocity. However, the method developed here is powerful enough to be extended analytically to higher order polynomial approximations, to obtain successive approximations to the exact self-similar solutions. Also obtained, for the first time, are exact asymptotic solutions, in analytic form, for the reflected shocks. Criteria are given that may enable one to make a choice between the two geometries for maximising compression or temperature of the gas. These solutions should be useful in the study of inertial confinement of a plasma. (author)
Internal reflection spectroscopic analysis of sulphide mineral surfaces
International Nuclear Information System (INIS)
Kaoma, J.
1989-01-01
To establish the reason for flotation of sulfide minerals in the absence of any conventional collector, internal reflection spectroscopic analysis (IRS) of their surfaces was conducted. sulfur, sulfates, thiosulfates, and hydrocarbonates have been detected on the surface of as-grand sulfide minerals. On sodium sulfide-treated surfaces, both sulfur and polysulfide have also been found to be present. From these findings, the flotation of sulfide minerals without collectors is discussed. (author). 26 refs
Directory of Open Access Journals (Sweden)
Tina Sabel
2014-02-01
Full Text Available Volume phase gratings, recorded in a photosensitive polymer by two-beam interference exposure, are studied by means of optical microscopy. Transmission gratings and reflection gratings, with periods in the order of 10 μm down to 130 nm, were investigated. Mapping of holograms by means of imaging in sectional view is introduced to study reflection-type gratings, evading the resolution limit of classical optical microscopy. In addition, this technique is applied to examine so-called parasitic gratings, arising from interference from the incident reference beam and the reflected signal beam. The appearance and possible avoidance of such unintentionally recorded secondary structures is discussed.
DIRC, the internally reflecting ring imaging Cherenkov detector for BABAR
International Nuclear Information System (INIS)
Adam, I.; Aston, D.
1997-11-01
The DIRC is a new type of Cherenkov imaging device that will be used for the first time in the BABAR detector at the asymmetric B-factory, PEP-II. It is based on total internal reflection and uses long, rectangular bars made from synthetic fused silica as Cherenkov radiator and light guide. The principles of the DIRC ring imaging Cherenkov technique are explained and results from the prototype program are presented. Its choice for the BABAR detector particle identification system is motivated, followed by a discussion of the quartz radiator properties and the detector design
Critical coupling of surface plasmons in graphene attenuated total reflection geometry
Energy Technology Data Exchange (ETDEWEB)
Cuevas, Mauro, E-mail: cuevas@df.uba.ar [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and Facultad de Ingeniería y Tecnología Informática, Universidad de Belgrano, Villanueva 1324, C1426BMJ, Buenos Aires (Argentina); Grupo de Electromagnetismo Aplicado, Departamento de Física, FCEN, Universidad de Buenos Aires and IFIBA, Ciudad Universitaria, Pabellón I, C1428EHA, Buenos Aires (Argentina)
2016-12-09
We study the optical response of an attenuated total reflection (ATR) structure in Otto configuration with graphene sheet, paying especial attention to the occurrence of total absorption. Our results show that due to excitation of surface plasmons on the graphene sheet, two different conditions of total absorption may occur. At these conditions, the energy loss of the surface plasmon by radiation is equal to its energy loss by absorption into the graphene sheet. We give necessary conditions on ATR parameters for the existence of total absorption. - Highlights: • Attenuated total reflection (ATR) structure with graphene sheet. • Surface plasmons and power matched condition. • Necessary conditions on ATR parameters for the existence of total absorption.
Critical coupling of surface plasmons in graphene attenuated total reflection geometry
International Nuclear Information System (INIS)
Cuevas, Mauro
2016-01-01
We study the optical response of an attenuated total reflection (ATR) structure in Otto configuration with graphene sheet, paying especial attention to the occurrence of total absorption. Our results show that due to excitation of surface plasmons on the graphene sheet, two different conditions of total absorption may occur. At these conditions, the energy loss of the surface plasmon by radiation is equal to its energy loss by absorption into the graphene sheet. We give necessary conditions on ATR parameters for the existence of total absorption. - Highlights: • Attenuated total reflection (ATR) structure with graphene sheet. • Surface plasmons and power matched condition. • Necessary conditions on ATR parameters for the existence of total absorption.
International Nuclear Information System (INIS)
Sarin, P.; Yoon, W.; Jurkschat, K.; Zschack, P.; Kriven, W. M.
2006-01-01
A four-lamp thermal image furnace has been developed to conduct high temperature x-ray diffraction in reflection geometry on oxide ceramic powder samples in air at temperatures ≤2050 K using synchrotron radiation. A refractory crucible made of Pt20%Rh alloy was used as a specimen holder. A material with well characterized lattice expansion properties was used as an internal crystallographic thermometer to determine the specimen temperature and displacement. The performance of the apparatus was verified by measurement of the thermal expansion properties of CeO 2 , MgO, and Pt which were found to be within ±3% of the acceptable values. The advantages, limitations, and important considerations of the instrument developed are discussed
Influence of internal channel geometry of gas turbine blade on flow structure and heat transfer
Szwaba, Ryszard; Kaczynski, Piotr; Telega, Janusz; Doerffer, Piotr
2017-12-01
This paper presents the study of the influence of channel geometry on the flow structure and heat transfer, and also their correlations on all the walls of a radial cooling passage model of a gas turbine blade. The investigations focus on the heat transfer and aerodynamic measurements in the channel, which is an accurate representation of the configuration used in aeroengines. Correlations for the heat transfer coefficient and the pressure drop used in the design of internal cooling passages are often developed from simplified models. It is important to note that real engine passages do not have perfect rectangular cross sections, but include a corner fillets, ribs with fillet radii and a special orientation. Therefore, this work provides detailed fluid flow and heat transfer data for a model of radial cooling geometry which has very realistic features.
Beyond the threshold for motion: river channel geometry and grain size reflect sediment supply
Pfeiffer, A.; Finnegan, N. J.; Willenbring, J. K.
2016-12-01
In many gravel-bedded rivers, floods that fill the channel banks create just enough shear stress to move the median-sized gravel particles on the bed surface (D50). Because this observation is common and is supported by theory, the coincidence of bankfull flow and the incipient motion of D50 has become a commonly employed assumption. However, not all natural gravel channels actually conform to this simple relationship; some channels maintain bankfull stresses far in excess of the critical stress required to initiate sediment transport. We use a database of >300 gravel-bedded rivers and >600 10Be-derived erosion rates from across North America to explore the hypothesis that sediment supply drives the magnitude of bankfull shear stress relative to the critical stress required to mobilize the median bed surface grain size. We find that the ratio of bankfull to critical stress is significantly higher in West Coast river reaches (2.47, n= 84) than in river reaches in the rest of the continent (1.03, n = 245). This pattern parallels trends in erosion rates (and hence sediment supplies). Supporting our hypothesis, we find a significant correlation between upstream erosion rate and local τ*bf/τ*c at sites where this comparison is possible. Our analysis reveals a decrease in bed surface armoring with increasing τ*bf/τ*c, suggesting that channels accommodate changes in sediment supply through adjustments in bed surface grain size, as predicted through numerical modeling. Our findings demonstrate that sediment supply is encoded in the bankfull hydraulic geometry of gravel-bedded channels through its control on bed surface grain size.
An algorithm for mass matrix calculation of internally constrained molecular geometries.
Aryanpour, Masoud; Dhanda, Abhishek; Pitsch, Heinz
2008-01-28
Dynamic models for molecular systems require the determination of corresponding mass matrix. For constrained geometries, these computations are often not trivial but need special considerations. Here, assembling the mass matrix of internally constrained molecular structures is formulated as an optimization problem. Analytical expressions are derived for the solution of the different possible cases depending on the rank of the constraint matrix. Geometrical interpretations are further used to enhance the solution concept. As an application, we evaluate the mass matrix for a constrained molecule undergoing an electron-transfer reaction. The preexponential factor for this reaction is computed based on the harmonic model.
An algorithm for mass matrix calculation of internally constrained molecular geometries
International Nuclear Information System (INIS)
Aryanpour, Masoud; Dhanda, Abhishek; Pitsch, Heinz
2008-01-01
Dynamic models for molecular systems require the determination of corresponding mass matrix. For constrained geometries, these computations are often not trivial but need special considerations. Here, assembling the mass matrix of internally constrained molecular structures is formulated as an optimization problem. Analytical expressions are derived for the solution of the different possible cases depending on the rank of the constraint matrix. Geometrical interpretations are further used to enhance the solution concept. As an application, we evaluate the mass matrix for a constrained molecule undergoing an electron-transfer reaction. The preexponential factor for this reaction is computed based on the harmonic model
Su-Yuen, Hsu
2011-01-01
Textile composite materials have good potential for constructing composite structures where the effects of three-dimensional stresses are critical or geometric complexity is a manufacturing concern. There is a recent interest in advancing competence within Langley Research Center for modeling the degradation of mechanical properties of textile composites. In an initial effort, two critical areas are identified to pursue: (1) Construction of internal geometry of textile composites, and (2) Rate-independent continuum damage mechanics. This report documents reviews on the two subjects. Various reviewed approaches are categorized, their assumptions, methods, and progress are briefed, and then critiques are presented. Each review ends with recommended research.
International Nuclear Information System (INIS)
Mikhailova, T V; Berzhansky, V N; Karavainikov, A V; Shaposhnikov, A N; Prokopov, A R; Lyashko, S D
2016-01-01
It is represented the results of modelling of magnetooptical properties in reflection polar geometry of one-dimensional photonic crystal, in which highly Bi-substituted iron garnet defect of composition Bi 1.0 Y 0.5 Gd 1.5 Fe 4.2 A l0.8 O 12 / Bi 2.8 Y 0.2 Fe 5 Oi 2 is located between the dielectric Bragg mirrors (SiO 2 / TiO 2 ) m (were m is number of layer pairs) and buffer SiO 2 and gold top layers of different thicknesses is placed on structure. The modification of spectral line- shapes of microcavity and Tamm plasmon-polariton modes depending on m is found. (paper)
Bryant, N. A.; Zobrist, A. L.; Walker, R. E.; Gokhman, B.
1985-01-01
Performance requirements regarding geometric accuracy have been defined in terms of end product goals, but until recently no precise details have been given concerning the conditions under which that accuracy is to be achieved. In order to achieve higher spatial and spectral resolutions, the Thematic Mapper (TM) sensor was designed to image in both forward and reverse mirror sweeps in two separate focal planes. Both hardware and software have been augmented and changed during the course of the Landsat TM developments to achieve improved geometric accuracy. An investigation has been conducted to determine if the TM meets the National Map Accuracy Standards for geometric accuracy at larger scales. It was found that TM imagery, in terms of geometry, has come close to, and in some cases exceeded, its stringent specifications.
PREFACE: The 7th International Seminar on Geometry, Continua and Microstructures
Burton, David A.
2007-04-01
It gives me great pleasure to present the proceedings of the 7th International Seminar on Geometry, Continua and Microstructures (GCM 7). The conference took place on 25-27 September 2006 at Lancaster University and the local organisers were Robin Tucker, Tim Walton, myself and Jonathan Gratus of the Lancaster University Mathematical Physics Group. Modern field theories of mechanically and electrically responsive continua have a wealth of interesting applications in physics. Such theories provide effective macroscopic models of complex systems, such as living tissue and material with dynamical defects, that capture macroscopic consequences of microscopic phenomena. GCM is an interdisciplinary conference series, initiated by the Eringen medallist Gérard A Maugin, that brings together physicists and applied mathematicians who have interests in continuum mechanics and differential geometry and who aim to develop new and powerful methods for analysing the behaviour of complex mechanical systems. The earlier conferences in the series were held in Paris, Madrid, Mannheim, Turin, Sinaia and Belgrade. This volume addresses a variety of topics including the physics of saturated porous media, the relationship between growth in living tissue and molecular transport, the mechanics of polymer bonds, the macroscopic properties of damaged elastomers, the mechanics of carbon nanotubes, the geometry of balance systems in Continuum Thermodynamics and wave propagation in the material manifold. I would like to warmly thank the rest of the organising committee and the conference participants for making GCM 7 an enjoyable and rewarding occasion. Photographs may be found at http://www.lancs.ac.uk/depts/spc/conf/gcm7/wss/index.htm David A Burton Editor
Effect of injector geometry on the performance of an internally mixed liquid atomizer
Energy Technology Data Exchange (ETDEWEB)
Kushari, A.
2010-11-15
This paper presents the results of an experimental study of the effect of injector's geometry on the performance of an internally mixed, air-assisted, liquid injector. In this type of injector a small amount of air is injected into a liquid stream within the injector. The interaction of the liquid with the atomizing air inside the injector induces atomization. The results presented in this paper show that the size of the droplets produced by the investigated injector decreases with a decrease in the air injection area. This is due to the increase in atomizing air injection velocity that accompanies the decrease in the air injection area, which improves atomization. This study also shows that the droplet sizes decrease with an increase in the injector's length, which is attributed to the increase in total interactive force. (author)
A Parametric Investigation of Nozzle Planform and Internal/External Geometry at Transonic Speeds
Cler, Daniel L.
1995-01-01
An experimental investigation of multidisciplinary (scarfed trailing edge) nozzle divergent flap geometry was conducted at transonic speeds in the NASA Langley 16-Foot Transonic Tunnel. The geometric parameters investigated include nozzle planform, nozzle contouring location (internal and/or external), and nozzle area ratio (area ratio 1.2 and 2.0). Data were acquired over a range of Mach Numbers from 0.6 to 1.2, angle-of-attack from 0.0 degrees to 9.6 degrees and nozzle pressure ratios from 1.0 to 20.0. Results showed that increasing the rate of change internal divergence angle across the width of the nozzle or increasing internal contouring will decrease static, aeropropulsive and thrust removed drag performance regardless of the speed regime. Also, increasing the rate of change in boattail angle across the width of the nozzle or increasing external contouring will provide the lowest thrust removed drag. Scarfing of the nozzle trailing edges reduces the aeropropulsive performance for the most part and adversely affects the nozzle plume shape at higher nozzle pressure ratios thus increasing the thrust removed drag. The effects of contouring were primary in nature and the effects of planform were secondary in nature. Larger losses occur supersonically than subsonically when scarfing of nozzle trailing edges occurs. The single sawtooth nozzle almost always provided lower thrust removed drag than the double sawtooth nozzles regardless the speed regime. If internal contouring is required, the double sawtooth nozzle planform provides better static and aeropropulsive performance than the single sawtooth nozzle and if no internal contouring is required the single sawtooth provides the highest static and aeropropulsive performance.
Zhao, Yongguang; Li, Chuanrong; Ma, Lingling; Tang, Lingli; Wang, Ning; Zhou, Chuncheng; Qian, Yonggang
2017-10-01
Time series of satellite reflectance data have been widely used to characterize environmental phenomena, describe trends in vegetation dynamics and study climate change. However, several sensors with wide spatial coverage and high observation frequency are usually designed to have large field of view (FOV), which cause variations in the sun-targetsensor geometry in time-series reflectance data. In this study, on the basis of semiempirical kernel-driven BRDF model, a new semi-empirical model was proposed to normalize the sun-target-sensor geometry of remote sensing image. To evaluate the proposed model, bidirectional reflectance under different canopy growth conditions simulated by Discrete Anisotropic Radiative Transfer (DART) model were used. The semi-empirical model was first fitted by using all simulated bidirectional reflectance. Experimental result showed a good fit between the bidirectional reflectance estimated by the proposed model and the simulated value. Then, MODIS time-series reflectance data was normalized to a common sun-target-sensor geometry by the proposed model. The experimental results showed the proposed model yielded good fits between the observed and estimated values. The noise-like fluctuations in time-series reflectance data was also reduced after the sun-target-sensor normalization process.
Energy loss from internal reflection off metal layers on glass
McDowell, M. W.; Bezuidenhout, D. F.; Klee, H. W.; Theron, E.
1983-12-01
The reflection characteristics of metal layers are considered for the situation where the electromagnetic radiation is incident from the glass side. Theoretical and measured reflectance values are presented which indicate that for some metals the reflection has a strong dependence on the refractive index of the incident medium. Some examples are given of recent cases where the above results were an important consideration in the choice of the metallic reflecting material. These results indicate that aluminium should not be automatically considered the best choice for the visible region nor gold for the infra-red.
Vasilkov, Alexander; Qin, Wenhan; Krotkov, Nickolay; Lamsal, Lok; Spurr, Robert; Haffner, David; Joiner, Joanna; Yang, Eun-Su; Marchenko, Sergey
2017-01-01
The Ozone Monitoring Instrument (OMI) cloud and NO2 algorithms use a monthly gridded surface reflectivity climatology that does not depend upon the observation geometry. In reality, reflection of incoming direct and diffuse solar light from land or ocean surfaces is sensitive to the sun sensor geometry. This dependence is described by the bidirectional reflectance distribution function (BRDF). To account for the BRDF, we propose to use a new concept of geometry-dependent Lambertian equivalent reflectivity (GLER). Implementation within the existing OMI cloud and NO2 retrieval infrastructure requires changes only to the input surface reflectivity database. GLER is calculated using a vector radiative transfer model with high spatial resolution BRDF information from MODIS over land and the Cox Munk slope distribution over ocean with a contribution from water-leaving radiance. We compare GLER and climatological LER at 466 nm, which is used in the OMI O2-O2cloud algorithm to derive effective cloud fractions. A detailed comparison of the cloud fractions and pressures derived with climatological and GLERs is carried out. GLER and corresponding retrieved cloud products are then used as input to the OMI NO2 algorithm. We find that replacing the climatological OMI-based LERs with GLERs can increase NO2 vertical columns by up to 50 % in highly polluted areas; the differences include both BRDF effects and biases between the MODIS and OMI-based surface reflectance data sets. Only minor changes to NO2 columns (within 5 %) are found over unpolluted and overcast areas.
The hidden hyperbolic geometry of international trade: World Trade Atlas 1870-2013.
García-Pérez, Guillermo; Boguñá, Marián; Allard, Antoine; Serrano, M Ángeles
2016-09-16
Here, we present the World Trade Atlas 1870-2013, a collection of annual world trade maps in which distance combines economic size and the different dimensions that affect international trade beyond mere geography. Trade distances, based on a gravity model predicting the existence of significant trade channels, are such that the closer countries are in trade space, the greater their chance of becoming connected. The atlas provides us with information regarding the long-term evolution of the international trade system and demonstrates that, in terms of trade, the world is not flat but hyperbolic, as a reflection of its complex architecture. The departure from flatness has been increasing since World War I, meaning that differences in trade distances are growing and trade networks are becoming more hierarchical. Smaller-scale economies are moving away from other countries except for the largest economies; meanwhile those large economies are increasing their chances of becoming connected worldwide. At the same time, Preferential Trade Agreements do not fit in perfectly with natural communities within the trade space and have not necessarily reduced internal trade barriers. We discuss an interpretation in terms of globalization, hierarchization, and localization; three simultaneous forces that shape the international trade system.
The hidden hyperbolic geometry of international trade: World Trade Atlas 1870–2013
García-Pérez, Guillermo; Boguñá, Marián; Allard, Antoine; Serrano, M. Ángeles
2016-01-01
Here, we present the World Trade Atlas 1870–2013, a collection of annual world trade maps in which distance combines economic size and the different dimensions that affect international trade beyond mere geography. Trade distances, based on a gravity model predicting the existence of significant trade channels, are such that the closer countries are in trade space, the greater their chance of becoming connected. The atlas provides us with information regarding the long-term evolution of the international trade system and demonstrates that, in terms of trade, the world is not flat but hyperbolic, as a reflection of its complex architecture. The departure from flatness has been increasing since World War I, meaning that differences in trade distances are growing and trade networks are becoming more hierarchical. Smaller-scale economies are moving away from other countries except for the largest economies; meanwhile those large economies are increasing their chances of becoming connected worldwide. At the same time, Preferential Trade Agreements do not fit in perfectly with natural communities within the trade space and have not necessarily reduced internal trade barriers. We discuss an interpretation in terms of globalization, hierarchization, and localization; three simultaneous forces that shape the international trade system. PMID:27633649
Furman, Rich; Coyne, Ann; Negi, Nalini Junko
2008-01-01
This descriptive article explores the uses of poetry and journaling exercises as means of helping students develop their self-reflective capacities within the context of international social work. First, self-reflection and its importance to social work practice and education is discussed. Second, the importance of self-reflection in international…
An Arduino-Based Experiment Designed to Clarify the Transition to Total Internal Reflection
Atkin, Keith
2018-01-01
The topic of refraction and reflection of light at the boundary of transparent media is a fundamentally important one. The special case of total internal reflection is however commonly misrepresented in elementary textbooks. This paper addresses the problem and describes an experimental procedure for measuring and displaying reflected and…
International Nuclear Information System (INIS)
Tourillon, Gerard; Dreesen, Laurent; Volcke, Cedric; Sartenaer, Yannick; Thiry, Paul A; Peremans, Andre
2007-01-01
We show that sum-frequency generation spectroscopy performed in the total internal reflection configuration (TIR-SFG) combined with a dense gold nanoparticles monolayer allows us to study, with an excellent signal to noise ratio and high signal to background ratio, the conformation of adsorbed molecules. Dodecanethiol (DDT) was used as probe molecules in order to assess the potentialities of the approach. An enhancement of more than one order of magnitude of the SFG signals arising from the adsorbed species is observed with the TIR geometry compared to the external reflection one while the SFG non-resonant contribution remains the same for both configurations. Although further work is required to fully understand the origin of the SFG process on nanoparticles, our work opens new possibilities for studying nanostructures
Murphy, M. A.; Taylor, M. H.
2006-12-01
Karakoram fault between 32°N to 30°N shows that its slip direction swings to more easterly orientations from north to south, paralleling the trace of the Himalayan thrust belt. We present a preliminary kinematic model to explain the fault slip data and regional geometry of these fault systems that incorporates eastward translation and counterclockwise rotation of a semi-triangular-shaped block. The Karakoram fault, the Dangardzong-Lopukangri fault system, and the Awong Co fault represent the major block boundaries. Although there is internal deformation within the block, inspection of satellite imagery and geologic maps suggests it is minor. We hypothesize that this strain pattern results from radial expansion of the Himalayan arc that causes regions within it to undergo arc-parallel stretching as well as arc-normal shortening. In this scenario rotation facilitates arc-normal shortening and arc-parallel stretching between south- western Tibetan plateau and Himalayan fold-thrust belt.
Analysis of 3D geometry in the stenosis of internal carotid artery siphon
International Nuclear Information System (INIS)
Xie Sheng; Xiao Jiangxi; Huang Yining; Zhang Chi; Li Deyu; Li Shuyu
2010-01-01
Objective: To identify the differences of 3D geometry of internal carotid artery (ICA) siphon between the controls and patients with ICA siphon stenosis. Methods: The clinical and imaging data of the inpatients under, vent carotid artery MRA in the past three years were collected. All patients were divided into the control group (17 males and 14 females with mean age of 67.5 years) and ICA siphon stenosis group (20 males and 9 females with mean age of 58.6 years). There were 5 smokers and 9 smokers in two groups, respectively. The atheroselerotic predisposing factors were compared between the two groups using chi-square test and paired t-test. In order to extract the 3D geometry of ICA siphon, the MRA data were transferred to PC and processed with the software of Mimics. The average curvature radius (ACR) was calculated and paired t-test was applied to determine the bilateral differences in the controls. According to the stenotic site of ICA siphon, ICA siphon stenosis group was divided into C2 segment stenosis group and C4 segment stenosis group. The differences of ACR among the control group, C2 segment stenosis group and C4 segment stenosis group were compared. In addition, the values of ACR in the stenotic and normal sides were compared with paired t-test in patients with unilateral C2 segment stenosis. Results: No significant differences were found in gender and smoker between the control group and the ICA siphon stenosis group (χ 2 =1.63, P>0.05; χ 2 =1.86, P>0.05). The systolic blood pressure was (146.6±21.3) mm Hg (1 mm Hg=0.133 kPa)and (140.3±17.3) mm Hg respectively in the ICA siphon stenosis group and the control group. The serum glucose level was (5.94±1.89) mmoL/L and (6.79±3.57) mmol/L respectively in two groups. The serum cholesterol level and triglyceride level were (4.57±0.87) mmol/L, (1.34±0.63) mmoL/L and (4.75±1.70) mmol/L, (1.54±0.72) mmol/L respectively in two groups. There were no differences in the atherosclerotic predisposing
Maintaining International Peace and Security: Reflections on Peace ...
African Journals Online (AJOL)
take measures and develop strategies to address the peacekeeping ... measures to achieve this purpose that are to be taken by the UN Security ..... For any democratic government it ..... financing for the mission, followed by a long procurement process for .... The view is also held that wide disparities in the international.
Reflections on the development of international nuclear law
International Nuclear Information System (INIS)
Lamm, Vanda
2017-01-01
Over the course of more than seven decades, treaty norms on the production and utilisation of nuclear energy have been developed, which together form a special section within international law. These norms are the consequence of the unique nature of the field, namely that on the one hand some aspects of the uses of nuclear energy should be covered by totally new and special norms (e.g. in the field of disarmament, seeking to eliminate or at least to control the spread of nuclear weapons, and nuclear weapons tests) and on the other hand that several traditional legal solutions were not suitable for the problems that emerged in connection with other uses of nuclear energy (like liability). In this article, three aspects of the development of that special section of international law will be explored, namely: the close connections between the regulation of peaceful and military uses of nuclear energy; the effects of nuclear catastrophes on the development of international nuclear legislation; and the interaction between soft law norms and binding norms in the area of nuclear law
Wang, Shinn-Fwu; Chiu, Ming-Hung; Chen, Wei-Wu; Kao, Fu-Hsi; Chang, Rong-Seng
2009-05-01
A small-displacement sensing system based on multiple total internal reflections in heterodyne interferometry is proposed. In this paper, a small displacement can be obtained only by measuring the variation in phase difference between s- and p-polarization states for the total internal reflection effect. In order to improve the sensitivity, we increase the number of total internal reflections by using a parallelogram prism. The theoretical resolution of the method is better than 0.417 nm. The method has some merits, e.g., high resolution, high sensitivity, and real-time measurement. Also, its feasibility is demonstrated.
Effect of the refraction factor of a plastic fiber shell on the internal reflection coefficient
International Nuclear Information System (INIS)
Pkrksypkin, A.I.; Ponomarev, L.I.
1992-01-01
Results of pilot studies of the effect of refraction factor of plastic fiber shell on the coefficient of light internal reflection in the fiber are presented. It is pointed, that the shell does not absorb the light, but effects the surface layer of the fiber centre so, that dependence of the coefficient of internal reflection on refraction factor of the shell may be described using Fresnel formulae. It is shown, that coefficient of internal reflection decreases with the increase of refraction factor. Technique to determine volume length of scintillation light absorption in the fiber is suggested
Internal Reflection Sensor for the Cone Penetrometer. Innovative Technology Summary Report
International Nuclear Information System (INIS)
None
2001-01-01
The Internal Reflection Sensor, developed by EIC Laboratories, Inc. as a cone penetrometer based technology, provides real-time detection of subsurface non-aqueous phase liquids (NAPLs). The internal reflection element is positioned against the wall of the cone penetrometer probe such that its sensing face is in contact with the soil or groundwater as the cone is pushed into the subsurface. When NAPL is present and in contact with the sensing face, the internally reflected light is diminished. This results in a decrease in the signal output by the detector - a positive indicator of NAPL presence
DIRC dreams: research directions for the next generation of internally reflected imaging counters
International Nuclear Information System (INIS)
Ratcliff, Blair N.; Spanier, Stefan
1999-01-01
Some conceptual design features of the total internally reflecting, imaging Cherenkov counter (DIRC) are described. Limits of the DIRC approach to particle identification, and a few features of alternative DIRC designs, are briefly explored
Energy Technology Data Exchange (ETDEWEB)
Ratcliff, Blair N
2001-09-18
Some general conceptual design features of total internally reflecting, imaging Cherenkov counters (DIRCs) are described. Limits of the DIRC approach to particle identification and a few features of alternative DIRC designs are briefly explored.
Precise shape reconstruction by active pattern in total-internal-reflection-based tactile sensor.
Saga, Satoshi; Taira, Ryosuke; Deguchi, Koichiro
2014-03-01
We are developing a total-internal-reflection-based tactile sensor in which the shape is reconstructed using an optical reflection. This sensor consists of silicone rubber, an image pattern, and a camera. It reconstructs the shape of the sensor surface from an image of a pattern reflected at the inner sensor surface by total internal reflection. In this study, we propose precise real-time reconstruction by employing an optimization method. Furthermore, we propose to use active patterns. Deformation of the reflection image causes reconstruction errors. By controlling the image pattern, the sensor reconstructs the surface deformation more precisely. We implement the proposed optimization and active-pattern-based reconstruction methods in a reflection-based tactile sensor, and perform reconstruction experiments using the system. A precise deformation experiment confirms the linearity and precision of the reconstruction.
Nursing student voices: reflections on an international service learning experience.
Main, E Eve; Garrett-Wright, Dawn; Kerby, Molly
2013-01-01
For the past decade participation in service and experiential learning in higher education has increased. The purpose of this study was to explore the lived experience of BSN and MSN students participating in a multidisciplinary service-learning course in a rural, underserved village in Belize. Researchers analyzed student journals utilizing qualitative data analysis techniques. There were eight consistent themes found in the student journals. The findings indicate that international service learning opportunities increase students' awareness of their place in a global society and the potential contribution they can make in society. For the past decade, service and experiential learning in higher education, including nursing education, has become increasingly important. Simply put, service and experiential learning combine community service activities with a student's academic study for the sole purpose of enriching the academic experience. As faculty, we feel the goal of baccalaureate and graduate nursing education is to produce an educated professional who will become a responsible citizen.
International migration, 1995: some reflections on an exceptional year.
Bedford, R
1996-10-01
"This paper examines the 1995 international migration statistics in the context of New Zealand's immigration policy, and with reference to the impact of migration on population change in 1995. Particular attention is focused on trying to unravel and interpret the statistics relating to net migration. Considerable confusion has arisen in the public debate about immigration because of uniformed and, at times, quite misleading use of information supplied by Statistics New Zealand and the Department of Labour.... This is a reprinted version of an article originally published in the New Zealand Journal of Geography in April 1996. The article has been reprinted because a number of tables in the earlier version were incorrectly reproduced. Any inconvenience caused by this problem is regretted." excerpt
Pedagogical Reflections on Internalizing Geopolitical Representations in Print Media
Directory of Open Access Journals (Sweden)
Wisam Khalid Abdul-Jabbar
2015-06-01
Full Text Available This essay explores how print media conceals implicit hegemonic texts that common readers unsuspectingly tend to internalize. These geopolitically infused texts are set to appropriate the reader’s worldviews by sublimating the kind of perceptions and notions they want to promote. This paper raises questions and awareness about how academia responds to these acts of internalization. These geopolitical texts, which dominate most of the print media and other resources, function at an imperceptible level to legitimize presuppositions and mould the world based on its own political imaginaries. To decode and interpret these largely shrewd texts requires a literacy skill that students need to acquire in different academic disciplines. This essay, therefore, explores how print media, such as newspapers and comics, attempts to legitimize knowledge through reports and stories that work at the subliminal level. Since all readers, students, instructors or researchers are vulnerable observers (Behar, 1996, because of our fallible human nature, the act of internalizing mediascaped knowledge becomes alarmingly simple and crucially effective on the way we are directed to perceive the world. By analogy, geopolitical texts are these id-instigated drives that the superego often suppresses and filters into dreams and fiction and yet they ominously somehow found their way out; they stealthily found expression and now they paint reality with their own biased colors. Can readers in the context be dream catchers? Cet article explore la manière dont les médias écrits dissimulent les textes hégémoniques implicites que les lecteurs ordinaires semblent assimiler à leur insu. Ces textes géopolitiquement insufflés sont appelés à approprier la vision du monde des lecteurs en sublimant le type de perceptions et de notions qu’ils souhaitent promouvoir. Cet article soulève des questions et sensibilise l’opinion sur la manière dont le monde universitaire r
Directory of Open Access Journals (Sweden)
Chenggang Zhu
2018-02-01
Full Text Available Total internal reflection (TIR is useful for interrogating physical and chemical processes that occur at the interface between two transparent media. Yet prism-coupled TIR imaging microscopes suffer from limited sensing areas due to the fact that the interface (the object plane is not perpendicular to the optical axis of the microscope. In this paper, we show that an electrically tunable lens can be used to rapidly and reproducibly correct the focal length of an oblique-incidence scanning microscope (OI-RD in a prism-coupled TIR geometry. We demonstrate the performance of such a correction by acquiring an image of a protein microarray over a scan area of 4 cm2 with an effective resolution of less than 20 microns. The electronic focal length tuning eliminates the mechanical movement of the illumination lens in the scanning microscope and in turn the noise and background drift associated with the motion.
Wicaksono, Sigit T.; Ardhyananta, Hosta; Rasyida, Amaliya; Hidayat, Mas Irfan P.
2018-04-01
Rapid Prototyping (RP) technologies, the manufacturing technology with less time consuming including high precission and complicated structure of products, are now become high demanding technologies. Those technologies can be base on top-down or bottom-up approaches. One of the bottom-up approach of RP technology is 3D printing machine. In this research, we have succeed to apply the droplet-based 3D printer to make the structured PLA (Polylactic Acid) materials with different internal geometry structures. The internal geometry used are triangle and honeycomb structure with different size of each symmetry axis of 4.5 mm and 9 mm and the thickness varied of 1 mm and 2 mm as well. The mechanical properties of those structures including tensile and bending stregth are evaluated by using tensile and flexural test respectively. Test results show that the best performance obtained by measuring its tensile and flexural strength is the sampel with triangle geometry of 9 mm geometrical size and 2 mm of thickness. The tensile strength and flexural strength values of the specimens are 59.2996 MPa and 123 MPa respectively.
GENIE - Generation of computational geometry-grids for internal-external flow configurations
Soni, B. K.
1988-01-01
Progress realized in the development of a master geometry-grid generation code GENIE is presented. The grid refinement process is enhanced by developing strategies to utilize bezier curves/surfaces and splines along with weighted transfinite interpolation technique and by formulating new forcing function for the elliptic solver based on the minimization of a non-orthogonality functional. A two step grid adaptation procedure is developed by optimally blending adaptive weightings with weighted transfinite interpolation technique. Examples of 2D-3D grids are provided to illustrate the success of these methods.
Biswas, Indranil; Morye, Archana; Parameswaran, A
2017-01-01
This volume is an outcome of the International conference held in Tata Institute of Fundamental Research and the University of Hyderabad. There are fifteen articles in this volume. The main purpose of the articles is to introduce recent and advanced techniques in the area of analytic and algebraic geometry. This volume attempts to give recent developments in the area to target mainly young researchers who are new to this area. Also, some research articles have been added to give examples of how to use these techniques to prove new results.
On fragments and geometry : The international legal order as metaphor and how it matters
Rajkovic, Nikolas
This 9, 871 word article was published in a special issue sponsored by the Institute for Global Law and Policy of the Harvard Law School. It questions how international legal theory is consumed over whether international law is “fragmenting”, yet without ever questioning where the meaning and
Spinning geometry = Twisted geometry
International Nuclear Information System (INIS)
Freidel, Laurent; Ziprick, Jonathan
2014-01-01
It is well known that the SU(2)-gauge invariant phase space of loop gravity can be represented in terms of twisted geometries. These are piecewise-linear-flat geometries obtained by gluing together polyhedra, but the resulting geometries are not continuous across the faces. Here we show that this phase space can also be represented by continuous, piecewise-flat three-geometries called spinning geometries. These are composed of metric-flat three-cells glued together consistently. The geometry of each cell and the manner in which they are glued is compatible with the choice of fluxes and holonomies. We first remark that the fluxes provide each edge with an angular momentum. By studying the piecewise-flat geometries which minimize edge lengths, we show that these angular momenta can be literally interpreted as the spin of the edges: the geometries of all edges are necessarily helices. We also show that the compatibility of the gluing maps with the holonomy data results in the same conclusion. This shows that a spinning geometry represents a way to glue together the three-cells of a twisted geometry to form a continuous geometry which represents a point in the loop gravity phase space. (paper)
Fasnacht, Zachary; Qin, Wenhan; Haffner, David P.; Loyola, Diego; Joiner, Joanna; Krotkov, Nickolay; Vasilkov, Alexander; Spurr, Robert
2017-01-01
Surface Lambertian-equivalent reflectivity (LER) is important for trace gas retrievals in the direct calculation of cloud fractions and indirect calculation of the air mass factor. Current trace gas retrievals use climatological surface LER's. Surface properties that impact the bidirectional reflectance distribution function (BRDF) as well as varying satellite viewing geometry can be important for retrieval of trace gases. Geometry Dependent LER (GLER) captures these effects with its calculation of sun normalized radiances (I/F) and can be used in current LER algorithms (Vasilkov et al. 2016). Pixel by pixel radiative transfer calculations are computationally expensive for large datasets. Modern satellite missions such as the Tropospheric Monitoring Instrument (TROPOMI) produce very large datasets as they take measurements at much higher spatial and spectral resolutions. Look up table (LUT) interpolation improves the speed of radiative transfer calculations but complexity increases for non-linear functions. Neural networks perform fast calculations and can accurately predict both non-linear and linear functions with little effort.
Vasilkov, Alexander; Qin, Wenhan; Krotkov, Nickolay; Lamsal, Lok; Spurr, Robert; Haffner, David; Joiner, Joanna; Yang, Eun-Su; Marchenko, Sergey
2017-01-01
Most satellite nadir ultraviolet and visible cloud, aerosol, and trace-gas algorithms make use of climatological surface reflectivity databases. For example, cloud and NO2 retrievals for the Ozone Monitoring Instrument (OMI) use monthly gridded surface reflectivity climatologies that do not depend upon the observation geometry. In reality, reflection of incoming direct and diffuse solar light from land or ocean surfaces is sensitive to the sun-sensor geometry. This dependence is described by the bidirectional reflectance distribution function (BRDF). To account for the BRDF, we propose to use a new concept of geometry-dependent Lambertian equivalent reflectivity (LER). Implementation within the existing OMI cloud and NO2 retrieval infrastructure requires changes only to the input surface reflectivity database. The geometry-dependent LER is calculated using a vector radiative transfer model with high spatial resolution BRDF information from the Moderate Resolution Imaging Spectroradiometer (MODIS) over land and the Cox-Munk slope distribution over ocean with a contribution from water-leaving radiance. We compare the geometry-dependent and climatological LERs for two wavelengths, 354 and 466 nm, that are used in OMI cloud algorithms to derive cloud fractions. A detailed comparison of the cloud fractions and pressures derived with climatological and geometry-dependent LERs is carried out. Geometry-dependent LER and corresponding retrieved cloud products are then used as inputs to our OMI NO2 algorithm. We find that replacing the climatological OMI-based LERs with geometry-dependent LERs can increase NO2 vertical columns by up to 50% in highly polluted areas; the differences include both BRDF effects and biases between the MODIS and OMI-based surface reflectance data sets. Only minor changes to NO2 columns (within 5 %) are found over unpolluted and overcast areas.
Vasilkov, Alexander; Qin, Wenhan; Krotkov, Nickolay; Lamsal, Lok; Spurr, Robert; Haffner, David; Joiner, Joanna; Yang, Eun-Su; Marchenko, Sergey
2017-01-01
Most satellite nadir ultraviolet and visible cloud, aerosol, and trace-gas algorithms make use of climatological surface reflectivity databases. For example, cloud and NO2 retrievals for the Ozone Monitoring Instrument (OMI) use monthly gridded surface reflectivity climatologies that do not depend upon the observation geometry. In reality, reflection of incoming direct and diffuse solar light from land or ocean surfaces is sensitive to the sun-sensor geometry. This dependence is described by the bidirectional reflectance distribution function (BRDF). To account for the BRDF, we propose to use a new concept of geometry-dependent Lambertian equivalent reflectivity (LER). Implementation within the existing OMI cloud and NO2 retrieval infrastructure requires changes only to the input surface reflectivity database. The geometry-dependent LER is calculated using a vector radiative transfer model with high spatial resolution BRDF information from the Moderate Resolution Imaging Spectroradiometer (MODIS) over land and the Cox-Munk slope distribution over ocean with a contribution from water-leaving radiance. We compare the geometry-dependent and climatological LERs for two wavelengths, 354 and 466 nm, that are used in OMI cloud algorithms to derive cloud fractions. A detailed comparison of the cloud fractions and pressures derived with climatological and geometry-dependent LERs is carried out. Geometry-dependent LER and corresponding retrieved cloud products are then used as inputs to our OMI NO2 algorithm. We find that replacing the climatological OMI-based LERs with geometry-dependent LERs can increase NO2 vertical columns by up to 50 % in highly polluted areas; the differences include both BRDF effects and biases between the MODIS and OMI-based surface reflectance data sets. Only minor changes to NO2 columns (within 5 %) are found over unpolluted and overcast areas.
Directory of Open Access Journals (Sweden)
Moira Stephens
2016-11-01
Full Text Available This article reports on the first Virtual International Practice Development Conference, held in May 2015 to celebrate International Nurses Day. The article describes key aspects of its planning, offers a flavour of the event itself and sets out an evaluation, including learning points and recommendations to assist with planning similar events in the future. Central to our learning are: The need for practice developers to grasp skills in technology associated with virtual space The need to embrace virtual space itself as another means by which creative and communicative spaces can be established for active learning and practice development activities The potential advantages that international virtual engagement has over face-to-face national or international engagement The delivery of this virtual event made a significant international contribution to global practice development activity within the International Practice Development Collaborative and to enabling practice developers to connect and celebrate on a more global basis. Implications for practice: Virtual space technology skills can assist with sharing and translating practice development research, innovations and critical commentary Virtual space can provide an adjunct to creative and communicative learning spaces Global networking opportunities can be developed and enhanced through the use of virtual space technology Practice developers need to role model the use of virtual technologies
Directory of Open Access Journals (Sweden)
Joanne Embree
2001-01-01
Full Text Available Ideally, editorials are written one to two months before publication in the Journal. It was my turn to write this one. I had planned to write the first draft the evening after my clinic on Tuesday, September 11. It didn't get done that night or during the next week. Somehow, the topic that I had originally chosen just didn't seem that important anymore as I, along my friends and colleagues, reflected on the changes that the events of that day were likely to have on our lives.
Symbolic Uses of Evaluation in the International Aid Sector: Arguments for Critical Reflection
McNulty, James
2012-01-01
Significant progress has been made in recent years to improve the quality of the evaluation of international aid. Increasingly, this includes an interest in improving the way evaluations are used to improve policies and programmes. However, the prevalence of symbolic use--a phenomenon that is often mentioned but rarely studied--reflects an…
Bitz, Michael; Emejulu, Obiajulu
2016-01-01
This article is an international reflection on literacy, creativity, and student engagement. The authors collaborated to help Nigerian youths and their teachers develop, design, and share original comic books. By leveraging student engagement for literacy learning, the authors highlighted the crucial role of creativity in the classroom. The…
Zheng, Desheng; Kaldaras, Leonora; Lu, H. Peter
2013-01-01
We have developed an integrated spectroscopy system combining total internal reflection fluorescence microscopy imaging with confocal single-molecule fluorescence spectroscopy for two-dimensional interfaces. This spectroscopy approach is capable of both multiple molecules simultaneously sampling and in situ confocal fluorescence dynamics analyses of individual molecules of interest. We have demonstrated the calibration with fluorescent microspheres, and carried out single-molecule spectroscop...
Saa'd AlDin, Kawther
2014-01-01
In 2010, the International Baccalaureate (IB) Organization mandated that all its schools, including Diploma (DP) schools, adhere to the collaborative planning and reflection requirements, which emphasized the importance of integrating its theory of knowledge (TOK) core component into all disciplines. Many schools officials and educations in Amman…
On Fragments and Geometry : The International Legal Order as Metaphor and How It Matters
N.M. Rajkovic (Nikolas)
2013-01-01
markdownabstract__Abstract__ This article engages the narrative of fragmentation in international law by asserting that legal academics and professionals have failed to probe more deeply into ‘fragmentation’ as a concept and, more specifically, as a spatial metaphor. The contention here is that
DEFF Research Database (Denmark)
Zacho, Mette; Damgaard, Sune; Lilleoer, Nikolaj Thomas
2012-01-01
The left internal thoracic artery (LITA) undergoes vascular remodelling when used for coronary artery bypass grafting. In this study we tested the hypothesis that the extent of the LITA remodelling late after coronary artery bypass grafting assessed by multidetector computed tomography is related...
Falsafioon, Mehdi; Aidoun, Zine; Poirier, Michel
2017-12-01
A wide range of industrial refrigeration systems are good candidates to benefit from the cooling and refrigeration potential of supersonic ejectors. These are thermally activated and can use waste heat recovery from industrial processes where it is abundantly generated and rejected to the environment. In other circumstances low cost heat from biomass or solar energy may also be used in order to produce a cooling effect. Ejector performance is however typically modest and needs to be maximized in order to take full advantage of the simplicity and low cost of the technology. In the present work, the behavior of ejectors with different nozzle exit positions has been investigated using a prototype as well as a CFD model. The prototype was used in order to measure the performance advantages of refrigerant (R-134a) flowing inside the ejector. For the CFD model, it is assumed that the ejectors are axi-symmetric along x-axis, thus the generated model is in 2D. The preliminary CFD results are validated with experimental data over a wide range of conditions and are in good accordance in terms of entrainment and compression ratios. Next, the flow patterns of four different topologies are studied in order to discuss the optimum geometry in term of ejector entrainment improvement. Finally, The numerical simulations were used to find an optimum value corresponding to maximized entrainment ratio for fixed operating conditions.
Total internal reflection second-harmonic generation: probing the alkane water interface
International Nuclear Information System (INIS)
Conboy, J.C.; Daschbach, J.L.; Richmond, G.L.
1994-01-01
Total internal reflection Second-Harmonic Generation (SHG) has been used to study a series of neat n-alkane/water interfaces. Polarization and incident angular-dependent measurements of the SH response show good agreement with theoretical predictions. Analysis of the incident and polarization angular-dependent SH response allows for determination of the nonlinear optical properties of molecules comprising the interfacial region. Based on Kleinman symmetry, the measured surface nonlinear susceptibilities suggest a high degree of interfacial order for octane and decane with less order indicated by the odd carbon n-alkanes examined, heptane and nonane. The SH response in reflection and transmission has been measured under a Total Internal Reflection (TIR) of the fundamental. The measured nonlinear susceptibilities in each case are found to be identical. (orig.)
Patterson, Brian M; Havrilla, George J
2006-11-01
The number of techniques and instruments available for Fourier transform infrared (FT-IR) microspectroscopic imaging has grown significantly over the past few years. Attenuated total internal reflectance (ATR) FT-IR microspectroscopy reduces sample preparation time and has simplified the analysis of many difficult samples. FT-IR imaging has become a powerful analytical tool using either a focal plane array or a linear array detector, especially when coupled with a chemometric analysis package. The field of view of the ATR-IR microspectroscopic imaging area can be greatly increased from 300 x 300 microm to 2500 x 2500 microm using a larger internal reflection element of 12.5 mm radius instead of the typical 1.5 mm radius. This gives an area increase of 70x before aberrant effects become too great. Parameters evaluated include the change in penetration depth as a function of beam displacement, measurements of the active area, magnification factor, and change in spatial resolution over the imaging area. Drawbacks such as large file size will also be discussed. This technique has been successfully applied to the FT-IR imaging of polydimethylsiloxane foam cross-sections, latent human fingerprints, and a model inorganic mixture, which demonstrates the usefulness of the method for pharmaceuticals.
Konstantinovskaya, E.; Malo, M.; Badina, F.
2014-12-01
Irregular basement geometry may affect thrust propagation in foreland fold-thrust belts creating a perturbation in structural continuity of hydrocarbon fields. Here we investigate how the irregular pattern of normal faults, along with the presence of uplifts and transverse faults in the Grenvillian basement has influenced the geometry and emplacement of frontal thrusts and duplexes in the parautochthonous domain of the southern Quebec Appalachians during the middle-late Ordovician Taconian orogeny. Integration of data from surface geology, wells, and 2D and 3D seismic reflection surveys into a regional-scale structural model is used to reconstruct the 3D geometry and emplacement history of one- and two-horse duplexes in the Joly-Saint-Flavien gas storage area. The normal hinterland to foreland sequence of thrusting in this area is complicated by the differential emplacement of tectonic slices along strike of the orogenic front, starting in the SW and developing subsequently to the NE within each structural level. The shortening related to duplex emplacement decreases laterally over the distance of 20 km from - 49% in the SW (Joly area) to - 31% in the NE (Saint-Flavien area). Duplex emplacement resulted from the differential forward propagation, deflexion and vertical-axis rotation of the roof thrust (Logan's Line), which, in turn, has been induced by the presence of frontal uplift and transverse faults in the basement. The structural-lithological analysis of tectonic slices and restoration of their initial location allows us to consider the lower slice of the Joly duplex as a structural trap comparable to the fractured reservoir in lower Ordovician dolomites of the Saint-Flavien duplex.
Directory of Open Access Journals (Sweden)
Francesco Pennacchio
2017-07-01
Full Text Available Ultrafast electron diffraction is a powerful technique to investigate out-of-equilibrium atomic dynamics in solids with high temporal resolution. When diffraction is performed in reflection geometry, the main limitation is the mismatch in group velocity between the overlapping pump light and the electron probe pulses, which affects the overall temporal resolution of the experiment. A solution already available in the literature involved pulse front tilt of the pump beam at the sample, providing a sub-picosecond time resolution. However, in the reported optical scheme, the tilted pulse is characterized by a temporal chirp of about 1 ps at 1 mm away from the centre of the beam, which limits the investigation of surface dynamics in large crystals. In this paper, we propose an optimal tilting scheme designed for a radio-frequency-compressed ultrafast electron diffraction setup working in reflection geometry with 30 keV electron pulses containing up to 105 electrons/pulse. To characterize our scheme, we performed optical cross-correlation measurements, obtaining an average temporal width of the tilted pulse lower than 250 fs. The calibration of the electron-laser temporal overlap was obtained by monitoring the spatial profile of the electron beam when interacting with the plasma optically induced at the apex of a copper needle (plasma lensing effect. Finally, we report the first time-resolved results obtained on graphite, where the electron-phonon coupling dynamics is observed, showing an overall temporal resolution in the sub-500 fs regime. The successful implementation of this configuration opens the way to directly probe structural dynamics of low-dimensional systems in the sub-picosecond regime, with pulsed electrons.
Ananyeva, K.; Wang, W.; Smucker, A. J.; Kravchenko, A. N.; Chun, H. C.; Rivers, M. L.
2010-12-01
Structure of soil aggregate interiors controls intra-aggregate processes and provides important contributions to the biogeochemical processes of the soil profile. Applications of computed microtomography (CMT) to soil science have enabled the direct and nondestructive analyses of internal aggregate pore structures within soil volumes. The main objective of this study was to employ CMT to examine the internal pore structures of soil aggregates, 4 to 6.3 mm across, sampled at 0-20 cm depths from contrasting long-term land management types. Intra-aggregate pore-size distributions were compared among land management types. Porosity below CMT resolution (tillage, grass vegetation) than that of aggregates managed by conventional tillage (CT) used for agriculture. There was also greater percentage of intra-aggregate pores >400 µm in aggregates from NS than CT or NT management systems. In the range 15-100 µm, however, porosity of CT aggregates exceeded that of NS and NT aggregates. Total intra-aggregate porosities were similar and higher for both CT and NS (34.6 and 34.7%, correspondingly) than the 32.6% for NT aggregates. Although statistically significant, this difference (CT or NS vs. NT) was practically small, requiring at least 48 replications to be detected. These results indicate that long-term differences in management affected intra-aggregate pore size distributions. Increased 15-100 µm porosity in CT aggregates is probably related to their greater fragility. A combination of higher microporosity (400 µm in NS aggregates may generate more favorable conditions for microbial activity through a combination of larger intra-aggregate regions with high water-holding capacities and increased aeration and preferential flow pathways for intra-aggregate solute and gas transport. Our current focus is comparing and relating specifics of internal pore structures in the aggregates from contrasting land management types, to the measurements of solution and microbial flow
Panigrahi, Ritwik; Srivastava, Suneel K.
2015-01-01
In present work, spherical core (polystyrene, PS)/shell (polypyrrole, PPy) has been synthesized via in situ chemical oxidative copolymerization of pyrrole (Py) on the surface of sulfonated PS microsphere followed by the formation of hollow polypyrrole (HPPy) shell by dissolving PS inner core in THF. Thereafter, we first time established that such fabricated novel art of morphology acts as a conducting trap in absorbing electromagnetic (EM) wave by internal reflection. Further studies have been extended on the formation of its silver nanocomposites HPPy/Ag to strengthen our contention on this novel approach. Our investigations showed that electromagnetic interference (EMI) shielding efficiency (SE) of HPPy (34.5-6 dB) is significantly higher compared to PPy (20-5 dB) in the frequency range of 0.5-8 GHz due to the trapping of EM wave by internal reflection. We also observed that EMI shielding is further enhanced to 59-23 in 10 wt% Ag loaded HPPy/Ag-10. This is attributed to the simultaneous contribution of internal reflection as well as reflection from outer surface. Such high EMI shielding capacity using conducting polymers are rarely reported.
Byrne, Gerard D; Vllasaliu, Driton; Falcone, Franco H; Somekh, Michael G; Stolnik, Snjezana
2015-11-02
In this work we utilize the combination of label-free total internal reflection microscopy and total internal reflectance fluorescence (TIRM/TIRF) microscopy to achieve a simultaneous, live imaging of single, label-free colloidal particle endocytosis by individual cells. The TIRM arm of the microscope enables label free imaging of the colloid and cell membrane features, while the TIRF arm images the dynamics of fluorescent-labeled clathrin (protein involved in endocytosis via clathrin pathway), expressed in transfected 3T3 fibroblasts cells. Using a model polymeric colloid and cells with a fluorescently tagged clathrin endocytosis pathway, we demonstrate that wide field TIRM/TIRF coimaging enables live visualization of the process of colloidal particle interaction with the labeled cell structure, which is valuable for discerning the membrane events and route of colloid internalization by the cell. We further show that 500 nm in diameter model polystyrene colloid associates with clathrin, prior to and during its cellular internalization. This association is not apparent with larger, 1 μm in diameter colloids, indicating an upper particle size limit for clathrin-mediated endocytosis.
Pedrera, Antonio; Marín-Lechado, Carlos; Galindo-Zaldívar, Jesús; García-Lobón, José Luis
2014-07-01
We have determined, for the first time, the 3D geometry of a sector of the eastern Internal Prebetic comprised between Parcent and Altea diapirs, combining structural, borehole and multichannel seismic reflection data. The tectonic structure of the Jurassic-Cretaceous carbonate series is characterized by regional ENE-WSW fold-and-thrusts that interact with oblique N-S and WNW-ESE folds, detached over Triassic evaporites and clays. The structural style comprises box-shape anticlines, and N-vergent anticlines with vertical to overturned limbs frequently bordered by reverse and strike-slip faults. The anticlines surround a triangular broad synclinal structure, the Tárbena basin, filled by a late Oligocene to Tortonian sedimentary sequence that recorded folding and thrusting history. The location and geometrical characteristics of fold-and-thrusts may be controlled by the positive inversion of pre-existing Mesozoic normal faults, and by the position and shape of near-surface diapirs composed of Triassic rocks. Therefore, we propose an initial near-surface diapir emplacement of Triassic evaporitic rocks driven by late Jurassic to early Cretaceous rifting of the southern Iberian paleomargin. Thrusting and folding started during the latest Oligocene (∼28-23 Ma) roughly orthogonal to the NW-directed shortening. Deformation migrated to the south during Aquitanian (∼23-20 Ma), when tectonic inversion implied the left-lateral transpressive reactivation of N-S striking former normal faults and right-lateral/reverse reactivation of inherited WNW-ESE faults. We show two mechanisms driving the extrusion of the diapirs during contraction: lateral migration of a pre-existing near-surface diapir associated with dextral transpression; and squeezing of a previous near-surface diapir at the front of an anticline. Our study underlines the value of 3D geological modeling to characterize geometry and kinematics of complex fold-and-thrust belts influenced by preexisting faults and
International Nuclear Information System (INIS)
Berkefeld, J.; Zanella, F.E.; Rosendahl, H.; Theron, J.G.; Guimaraens, L.; Treggiari-Venzi, M.M.
2002-01-01
A measurement system is proposed to evaluate reconstructive effects of carotid stents on the geometry of the carotid bifurcation and the course of the internal carotid artery. To describe deviations of the stenotic internal carotid artery (ICA) from the extended axis of the common carotid artery (CCA) the CCA-ICA angle is measured between the CCA midaxis and the midaxis of the stenotic ICA segment. Maximal extensions of ICA tortuosities perpendicular to the course of the CCA axis are defined as ICA offset. The measurements were applied to DSA images of 224 carotid stenoses to evaluate variation and correlation between the two parameters. Comparative pre- and post-stent evaluation was performed in two series of 55 and 31 carotid stenoses treated with Wallstents and in a historic control group of 35 stenoses treated with Strecker stents. Straight course of the ICA was associated with low angle and low offset values, whereas tortuous course of the ICA showed larger angle and offset. A moderate linear correlation between the two parameters was found. Corresponding to a straightening of the stented segment, Wallstents reduced mean angle and offset values significantly. In five cases of the second series of Wallstents, transferrals of curves above the distal stent end associated with kinks were observed, and offset remained constant or increased. Strecker stent implantation caused no significant changes of bifurcational geometry. The proposed parameters corresponded to visual aspects of ICA tortuosity and detected reconstructive effects of self-expanding Wallstents on the ICA course. The measurement system may provide a basis for geometric evaluation of different stent types or implantation concepts with the aim: to optimize anatomic recanalization results in tortuous high angle-high offset bifurcations. (orig.)
Ritwik Panigrahi; Suneel K. Srivastava
2015-01-01
In present work, spherical core (polystyrene, PS)/shell (polypyrrole, PPy) has been synthesized via in situ chemical oxidative copolymerization of pyrrole (Py) on the surface of sulfonated PS microsphere followed by the formation of hollow polypyrrole (HPPy) shell by dissolving PS inner core in THF. Thereafter, we first time established that such fabricated novel art of morphology acts as a conducting trap in absorbing electromagnetic (EM) wave by internal reflection. Further studies have bee...
Directory of Open Access Journals (Sweden)
Nikolenko Nataliya V.
2013-12-01
Full Text Available The article identifies the degree of correspondence of the national Provisions (Standard of Business Accounting (PSBA Lease with the international standard and provides recommendations with respect to their closing up. On the results of the study the author provides specific features of international and national standards – the existing IFRS 17 Lease and national PSBA 14 Lease by the following components: definition of lease, its classification and reflection in accounting. Also the text of PSBA 31 Financial Expenditures is supplemented with provisions on capitalisation of financial expenditures prospectively, which would allow avoidance of correction of the balance of the retained income and provision of comparative information for previous periods. The article provides an algorithm of division of lease for accounting purposes on the basis of international standards. Its use would ensure correctness of reflection of lease operations in accounting and would serve as a basis for development of methodical provisions with respect to accounting. By the result of the study the author forms definition of the qualification asset as an asset which requires considerable time for its creation, preparation for target use, sales or acquisition of the ownership right. Capitalisation of such expenditures would allow non-reduction of the accounting income and also would provide a possibility to reflect financial expenditures in accordance with their economic essence.
Beyond ‘Innocents Abroad’: Reflecting on Sustainability Issues During International Study Trips
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Anne H. Reilly
2016-12-01
Full Text Available With ecosystems and populations in many regions threatened by rapid development, sustainability is a critical component for businesses in mature markets and emerging economies alike. The International Association of Jesuit Business Schools notes that global sustainability involves a broad set of interconnected issues ranging from environmental preservation to social justice to desirable production and consumption patterns. Jesuit business schools are uniquely positioned to address sustainability issues with their focus on teaching managerial content in tandem with corporate social responsibility. Further, the Ignatian Pedagogy Paradigm of experience, reflection, and action would suggest that business students may benefit from reflective observation in support of learning about sustainability. In this paper, we examine the international study trip as an opportunity for students to learn about sustainability, with results suggesting that student understanding about the broad sustainability domain may be enhanced through the study abroad experience. We discuss how two classes of primarily American MBA students traveling to emerging markets (one class to Santiago, Chile and one class to Johannesburg, South Africa were able to connect local business practices with economic and social as well as environmental sustainability issues, enhancing both student engagement and learning outcomes. Further, these students’ sustainability experiences while in an unfamiliar environment provided the opportunity to apply the potentially transformative experience, reflection, and action components of the Ignatian Pedagogy Paradigm. Compared to similar graduate business students enrolled in regular classes, we argue that these students discerned deeper connections with the economic, social, and environmental issues of sustainability.
Internal-wave reflection from uniform slopes: higher harmonics and Coriolis effects
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T. Gerkema
2006-01-01
Full Text Available Weakly nonlinear reflection of internal waves from uniform slopes produces higher harmonics and mean fields; the expressions are here derived for constant stratification and with Coriolis effects fully included, i.e. the horizontal component of the earth rotation vector (referred to as 'non-traditional'' is taken into account. Uniformity in one of the horizontal directions is assumed. It is shown that solutions can be as readily derived with as without ; hence there is no need to make the so-called Traditional Approximation. Examples of reflecting internal-wave beams are presented for super-inertial, inertial and sub-inertial frequencies. The problem of resonant and non-resonant forcing of the second harmonic is studied for single plane waves; unlike under the Traditional Approximation, the problem of reflection from a horizontal bottom no longer forms a singular case. Non-traditional effects are favourable to resonant forcing at near-tidal rather than near-inertial frequencies, and generally increase the intensity of the second harmonic. Strong stratification tends to suppress non-traditional effects, but a near-total suppression is only attained for high values of stratification that are characteristic of the seasonal thermocline; in most parts of the ocean, non-traditional effects can therefore be expected to be important.
Zusin, Dmitriy; Tengdin, Phoebe M.; Gopalakrishnan, Maithreyi; Gentry, Christian; Blonsky, Adam; Gerrity, Michael; Legut, Dominik; Shaw, Justin M.; Nembach, Hans T.; Silva, T. J.; Oppeneer, Peter M.; Kapteyn, Henry C.; Murnane, Margaret M.
2018-01-01
The microscopic state of a magnetic material is characterized by its resonant magneto-optical response through the off-diagonal dielectric tensor component ɛx y. However, the measurement of the full complex ɛx y in the extreme ultraviolet spectral region covering the M absorption edges of 3 d ferromagnets is challenging due to the need for either a careful polarization analysis, which is complicated by a lack of efficient polarization analyzers, or scanning the angle of incidence in fine steps. Here, we propose and demonstrate a technique to extract the complex resonant permittivity ɛx y simply by scanning the polarization angle of linearly polarized high harmonics to measure the magneto-optical asymmetry in reflection geometry. Because this technique is more practical and faster to experimentally implement than previous approaches, we can directly measure the full time evolution of ɛx y(t ) during laser-induced demagnetization across the entire M2 ,3 absorption edge of cobalt with femtosecond time resolution. We find that for polycrystalline Co films on an insulating substrate, the changes in ɛx y are uniform throughout the spectrum, to within our experimental precision. This result suggests that, in the regime of strong demagnetization, the ultrafast demagnetization response is primarily dominated by magnon generation. We estimate the contribution of exchange-splitting reduction to the ultrafast demagnetization process to be no more than 25%.
Bohannon, Kevin P; Holz, Ronald W; Axelrod, Daniel
2017-10-01
The refractive index in the interior of single cells affects the evanescent field depth in quantitative studies using total internal reflection (TIR) fluorescence, but often that index is not well known. We here present method to measure and spatially map the absolute index of refraction in a microscopic sample, by imaging a collimated light beam reflected from the substrate/buffer/cell interference at variable angles of incidence. Above the TIR critical angle (which is a strong function of refractive index), the reflection is 100%, but in the immediate sub-critical angle zone, the reflection intensity is a very strong ascending function of incidence angle. By analyzing the angular position of that edge at each location in the field of view, the local refractive index can be estimated. In addition, by analyzing the steepness of the edge, the distance-to-substrate can be determined. We apply the technique to liquid calibration samples, silica beads, cultured Chinese hamster ovary cells, and primary culture chromaffin cells. The optical technique suffers from decremented lateral resolution, scattering, and interference artifacts. However, it still provides reasonable results for both refractive index (~1.38) and for distance-to-substrate (~150 nm) for the cells, as well as a lateral resolution to about 1 µm.
Kuang, Cuifang; Ali, M Yakut; Hao, Xiang; Wang, Tingting; Liu, Xu
2010-10-01
In order to achieve a higher axial resolution for displacement measurement, a novel method is proposed based on total internal reflection filter and confocal microscope principle. A theoretical analysis of the basic measurement principles is presented. The analysis reveals that the proposed confocal detection scheme is effective in enhancing the resolution of nonlinearity of the reflectance curve greatly. In addition, a simple prototype system has been developed based on the theoretical analysis and a series of experiments have been performed under laboratory conditions to verify the system feasibility, accuracy, and stability. The experimental results demonstrate that the axial resolution in displacement measurements is better than 1 nm in a range of 200 nm which is threefold better than that can be achieved using the plane reflector.
Superresolution confocal technology for displacement measurements based on total internal reflection
International Nuclear Information System (INIS)
Kuang Cuifang; Hao Xiang; Wang Tingting; Liu Xu; Ali, M. Yakut
2010-01-01
In order to achieve a higher axial resolution for displacement measurement, a novel method is proposed based on total internal reflection filter and confocal microscope principle. A theoretical analysis of the basic measurement principles is presented. The analysis reveals that the proposed confocal detection scheme is effective in enhancing the resolution of nonlinearity of the reflectance curve greatly. In addition, a simple prototype system has been developed based on the theoretical analysis and a series of experiments have been performed under laboratory conditions to verify the system feasibility, accuracy, and stability. The experimental results demonstrate that the axial resolution in displacement measurements is better than 1 nm in a range of 200 nm which is threefold better than that can be achieved using the plane reflector.
International Nuclear Information System (INIS)
Kim, Kyujung; Cho, Eun-Jin; Suh, Jin-Suck; Huh, Yong-Min; Kim, Donghyun; Kim, Dong Jun
2009-01-01
We investigated evanescent field enhancement based on subwavelength nanogratings for improved sensitivity in total internal reflection microscopy of live cells. The field enhancement is associated with subwavelength-grating-coupled plasmon excitation. An optimum sample employed a silver grating on a silver film and an SF10 glass substrate. Field intensity was enhanced by approximately 90% when measured by fluorescent excitation of microbeads relative to that on a bare prism as a control, which is in good agreement with numerical results. The subwavelength-grating-mediated field enhancement was also applied to live cell imaging of quantum dots, which confirmed the sensitivity enhancement qualitatively.
Nonpolarizing beam splitter designed by frustrated total internal reflection inside a glass cube.
Xu, Xueke; Shao, Jianda; Fan, Zhengxiu
2006-06-20
A method for the design of an all-dielectric nonpolarizing prism beam splitter utilizing the principle of frustrated total internal reflection is reported. The nonpolarizing condition for a prism beam splitter is discussed, and some single layer design examples are elaborated. The concept can be applied to a wide range of wavelengths and arbitrary transmittance values, and with the help of a computer design program examples of 400-700 nm, T(p)=T(s)=0.5+/-0.01, with incident angles of 45 degrees and 62 degrees are given. In addition, the sensitivity and application of the design are also discussed.
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Marcelina Cardoso Dos Santos
2017-06-01
Full Text Available We propose a new strategy to evaluate adhesion strength at the single cell level. This approach involves variable-angle total internal reflection fluorescence microscopy to monitor in real time the topography of cell membranes, i.e. a map of the membrane/substrate separation distance. According to the Boltzmann distribution, both potential energy profile and dissociation energy related to the interactions between the cell membrane and the substrate were determined from the membrane topography. We have highlighted on glass substrates coated with poly-L-lysine and fibronectin, that the dissociation energy is a reliable parameter to quantify the adhesion strength of MDA-MB-231 motile cells.
Microplate-compatible total internal reflection fluorescence microscopy for receptor pharmacology
Chen, Minghan; Zaytseva, Natalya V.; Wu, Qi; Li, Min; Fang, Ye
2013-05-01
We report the use of total internal reflection fluorescence (TIRF) microscopy for analyzing receptor pharmacology and the development of a microplate-compatible TIRF imaging system. Using stably expressed green fluorescence protein tagged β2-adrenergic receptor as the reporter, we found that the activation of different receptors results in distinct kinetic signatures of the TIRF intensity of cells. These TIRF signatures closely resemble the characteristics of their respective label-free dynamic mass redistribution signals in the same cells. This suggests that TIRF in microplate can be used for profiling and screening drugs.
Identifying diffraction effects in measured reflectances
Holzschuch , Nicolas; Pacanowski , Romain
2015-01-01
International audience; There are two different physical models connecting the micro-geometry of a surface and its physical reflectance properties (BRDF). The first, Cook-Torrance, assumes geometrical optics: light is reflected and masked by the micro-facets. In this model, the BRDF depends on the probability distribution of micro-facets normals. The second, Church-Takacs, assumes diffraction by the micro-geometry. In this model, the BRDF depends on the power spectral distribution of the surf...
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Etik Rahayu
2012-06-01
Full Text Available Tujuan penelitian ini adalah untuk mendeskripsikanÂ domain kognitif dan aspek kognitif (required behavior soal matematika dalam Buku Matematika Bilingual untuk Sekolah Menengah Pertama (SMP Kelas VIII berdasarkan kriteria International Assessment TIMSS 2007 dan proporsinya. Metode penelitian yang digunakan adalah deskriptif kualitatif, dengan subjek penelitian adalah soal geometri dalam Buku Matematika Bilingual SMP. yang berjudul â€œMathematics for Junior High School Grade VIII 1st Semesterâ€ dan â€œMathematics for Junior High School Grade VIII 2nd Semesterâ€ karangan karangan M. Cholik Adinawan dan Sugijono. Pengumpulan data menggunakan metode observasi dan wawancara tentang penggunaan buku matematika bilingual yang paling banyak digunakan di kota semarang. Pedoman analisis soal berdasarkan kriteria International Assessment TIMSS 2007, dengan validasi hasil oleh ahli. Hasil penelitian menunjukkan bahwa soal yang dianalisis memuat satu hingga tujuh aspek kognitif. Sebagian besar soal memuat 4 aspek kognitif yaitu 44.04 %, diikuti soal dengan 3 aspek kognitifÂ yaitu 36, 42%,Â soal dengan 2 aspek kognitif yaitu 14, 90%, kemudian 1,99% untuk soal dengan 1 atau 5 aspek kognitif, dan 0,33% untuk soal dengan 6 atau 7 aspek kognitif. Proporsi tinggi pada recall (28.26% dan compute (26.57%, diikuti dengan SRP (10.85%, implement (10.65%, retrieve (8.36%, recognize (6.17%, analyze (1.99%, measure (1.59%, generalize (1.09%, SNRP (1.00%, classify (0.80%, represent (0.80%, justify (0.80%, select (0.60%, model (0.30%, synthesis (0.20%. Secara keseluruhan berdasarkan International Assessment TIMSS 2007 soal yang termasuk domain knowing memiliki persentase paling tinggi (52.28%, domain knowing-applying (24.83%, domain knowing- reasoning (12.91%, dan hanya sedikit yang termasuk domain knowing-apllying-reasoning (3.97%. Serta terdapat 4 soal (1.32% yang mempunyai ketidaksesuaian penggunaan mathematics terms serta 1 soal (0
International Nuclear Information System (INIS)
Lopuski, J.
1993-01-01
This book deals with deals of the complex issues of liability and compensation for nuclear damage which have been considered in the course of the work of the IAEA concerning the revision of the Vienna Convention on nuclear liability. It presents, in an orderly way, personal reflections of its author based on his experience gathered in years 1989-1992 when participating in this work. Necessarily it contains in some of its parts references to documents of the IAEA Standing Committee on Nuclear Liability; these documents because of their length could not be reproduced. Consequently these parts may not be fully intelligible for those who have not participated in or closely followed the Committee's work. The IAEA work on liability for nuclear damage was initiated in the wake of the impact made on the world's public opinion by the Chernobyl incident and its transboundary effects; issues of international state liability and full compensation have been raised. But humanitarian ideas have quickly been confronted with cold calculations of the cost of financial protection for victims and an open unwillingness of some nuclear states has been manifested. After three years of discussions no wide consensus could be reached on some basic issues, such as: relationship between international state and civil liability regimes, structure of international legislation, concept of nuclear damage, limits of compensation, role of public funds or jurisdiction. The author presents his approach to these controversial issue, trying to provide at the same time a theoretical outline for the future international legislation on nuclear liability. (author)
ELiXIR—Solid-State Luminaire With Enhanced Light Extraction by Internal Reflection
Allen, Steven C.; Steckl, Andrew J.
2007-06-01
A phosphor-converted light-emitting diode (pcLED) luminaire featuring enhanced light extraction by internal reflection (ELiXIR) with efficacy of 60 lm/W producing 18 lumens of yellowish green light at 100 mA is presented. The luminaire consists of a commercial blue high power LED, a polymer hemispherical shell lens with interior phosphor coating, and planar aluminized reflector. High extraction efficiency of the phosphor-converted light is achieved by separating the phosphor from the LED and using internal reflection to steer the light away from lossy reflectors and the LED package and out of the device. At 10 and 500 mA, the luminaire produces 2.1 and 66 lumens with efficacies of 80 and 37 lm/W, respectively. Technological improvements over existing commercial LEDs, such as more efficient pcLED packages or, alternatively, higher efficiency green or yellow for color mixing, will be essential to achieving 150 200 lm/W solid-state lighting. Advances in both areas are demonstrated.
International Nuclear Information System (INIS)
Gleńska-Olender, J.; Dworecki, K.; Sęk, S.; Kwinkowski, M.; Kaca, W.
2013-01-01
Total internal reflection ellipsometry (TIRE), a label-free optical detection technique for studying interactions between biomolecules, was used to examine the adsorption of various forms of lipopolysaccharides (LPSs) isolated from Proteus mirabilis S1959, R110, and R45 strains on a gold surface. The thickness of the adsorbed layers was determined by TIRE, with the average values for S1959, R110, and R45 LPS layers being 78 ± 5, 39 ± 3, and 12 ± 2 nm, respectively. The thickness of LPS layers corresponds to the presence and length of O-specific parts in P. mirabilis LPS molecules. Atomic force microscopy was used as a complementary technique for visualizing lipopolysaccharides on the surface. Force measurements seem to confirm the data obtained from TIRE experiments. - Highlights: • Proteus mirabilis lipopolysaccharides were adsorbed on the gold surface. • Thickness of adsorbed layers was determined by total internal reflection ellipsometry. • Atomic force microscopy was used to visualize lipopolysaccharide build-up on gold surface. • Time is important in the evolution of biomolecular film thickness created on gold surface
Deng, Zhichao; Wang, Jin; Ye, Qing; Sun, Tengqian; Zhou, Wenyuan; Mei, Jianchun; Zhang, Chunping; Tian, Jianguo
2016-01-01
The complex refractive index dispersion (CRID), which contains the information on the refractive index dispersion and extinction coefficient spectra, is an important optical parameter of biotissue. However, it is hard to perform the CRID measurement on biotissues due to their high scattering property. Continuous CRID measurement based on internal reflection (CCRIDM-IR) is introduced. By using a lab-made apparatus, internal reflectance spectra of biotissue samples at multiple incident angles were detected, from which the continuous CRIDs were calculated based on the Fresnel formula. Results showed that in 400- to 750-nm range, hemoglobin solution has complicated dispersion and extinction coefficient spectra, while other biotissues have normal dispersion properties, and their extinction coefficients do not vary much with different wavelengths. The normal dispersion can be accurately described by several coefficients of dispersion equations (Cauchy equation, Cornu equation, and Conrady equation). To our knowledge, this is the first time that the continuous CRID of scattering biotissue over a continuous spectral region is measured, and we hereby have proven that CCRIDM-IR is a good method for continuous CRID research of biotissue.
Energy Technology Data Exchange (ETDEWEB)
Gleńska-Olender, J., E-mail: joannaglenska@wp.pl [Institute of Biology, Jan Kochanowski University, 25-406 Kielce (Poland); Świętokrzyski Biobank, Regional Science and Technology Center, 26-060 Chęciny (Poland); Dworecki, K. [Institute of Physics, Jan Kochanowski University, 25-406 Kielce (Poland); Sęk, S. [Department of Chemistry, University of Warsaw, 02-093 Warsaw (Poland); Kwinkowski, M.; Kaca, W. [Institute of Biology, Jan Kochanowski University, 25-406 Kielce (Poland)
2013-12-02
Total internal reflection ellipsometry (TIRE), a label-free optical detection technique for studying interactions between biomolecules, was used to examine the adsorption of various forms of lipopolysaccharides (LPSs) isolated from Proteus mirabilis S1959, R110, and R45 strains on a gold surface. The thickness of the adsorbed layers was determined by TIRE, with the average values for S1959, R110, and R45 LPS layers being 78 ± 5, 39 ± 3, and 12 ± 2 nm, respectively. The thickness of LPS layers corresponds to the presence and length of O-specific parts in P. mirabilis LPS molecules. Atomic force microscopy was used as a complementary technique for visualizing lipopolysaccharides on the surface. Force measurements seem to confirm the data obtained from TIRE experiments. - Highlights: • Proteus mirabilis lipopolysaccharides were adsorbed on the gold surface. • Thickness of adsorbed layers was determined by total internal reflection ellipsometry. • Atomic force microscopy was used to visualize lipopolysaccharide build-up on gold surface. • Time is important in the evolution of biomolecular film thickness created on gold surface.
Directory of Open Access Journals (Sweden)
Kim Myung K
2011-09-01
Full Text Available Abstract Background Total internal reflection fluorescence microscopy (TIRFM is a powerful tool for observing fluorescently labeled molecules on the plasma membrane surface of animal cells. However, the utility of TIRFM in plant cell studies has been limited by the fact that plants have cell walls, thick peripheral layers surrounding the plasma membrane. Recently, a new technique known as variable-angle epifluorescence microscopy (VAEM was developed to circumvent this problem. However, the lack of a detailed analysis of the optical principles underlying VAEM has limited its applications in plant-cell biology. Results Here, we present theoretical and experimental evidence supporting the use of variable-angle TIRFM in observations of intact plant cells. We show that when total internal reflection occurs at the cell wall/cytosol interface with an appropriate angle of incidence, an evanescent wave field of constant depth is produced inside the cytosol. Results of experimental TIRFM observations of the dynamic behaviors of phototropin 1 (a membrane receptor protein and clathrin light chain (a vesicle coat protein support our theoretical analysis. Conclusions These findings demonstrate that variable-angle TIRFM is appropriate for quantitative live imaging of cells in intact tissues of Arabidopsis thaliana.
Jackson, Christopher; Schofield, Nick; Magee, Craig; Golenkov, Bogdan
2017-04-01
Emplacement of magma in the shallow subsurface can result in the development of dome-shaped folds at the Earth's surface. These so-called 'forced folds' have been described in the field and in subsurface datasets, although the exact geometry of the folds and the nature of their relationship to underlying sills remains unclear and, in some cases, controversial. As a result, the utility of these features in tracking the subsurface movement of magma, and predicting the potential size and location of potentially hazardous volcanic eruptions, is uncertain. Here we use high-quality, 2D seismic reflection and borehole data from the Ceduna sub-basin, offshore southern Australia to describe the structure and infer the evolution of igneous sill-related forced folds in the Bight Basin Igneous Complex (BBIC). We mapped 33 igneous sills, which were emplaced 200-1500 m below the palaeo-seabed in an Upper Cretaceous, coal-bearing, predominantly coastal-plain succession. The intrusions, which are expressed as packages of high-amplitude reflections, are 32-250 m thick and 7-19 km in diameter. They are overlain by dome-shaped folds, which are up to 17 km wide and display up to 210 m of relief. The edges of these folds coincide with the margins of the underlying sills and the folds display the greatest relief where the underlying sills are thickest; the folds are therefore interpreted as forced folds that formed in response to emplacement of magma in the shallow subsurface. The folds are onlapped by Lutetian (middle Eocene) strata, indicating they formed and the intrusions were emplaced during the latest Ypresian (c. 48 Ma). We demonstrate that fold amplitude is typically less than sill thickness even for sills with very large diameter-to-depth ratios, suggesting that pure elastic bending (forced folding) of the overburden is not the only process accommodating magma emplacement, and that supra-sill compaction may be important even at relatively shallow depths. Based on the
Directory of Open Access Journals (Sweden)
Ergün Köksoy
2015-11-01
Full Text Available Public diplomacy is described as a new form of relations and communications between countries and societies in the field of international relations with the process of globalisation. The subject of refugees shown among the priority issues can be solved through international cooperation and solidarity with its results affecting all countries and societies, that’s why becoming part of public diplomacy. Asylum seekers and refugee rights are guaranteed by the Universal Declaration of Human Rights and considered to be an area that the international community needs to take the roles and share responsibilities. In this aspect, it is shown as global responsibilities and part of the humanitarian sensibility of countries and societies. In one hand, asylum seekers and refugees are considered to be the subject of the problem and crisis, on the other hand, due to contributing to the human and cultural interaction between the different communities, these are specified as part of public diplomacy. This article discusses the relationship between public diplomacy and refugees relations which provides the interaction between countries and effects the prestige and perception of them. In the study, to reveal the reflections of Turkey’s Refugees Relations on the International Media, three highest-circulation newspapers (“The Guardian”, “Le Monde”, “Der Spiegel” will be choosen from three important EU countries (United Kingdom, France, Germany. These newspapers’ headlines and news content which related to Turkey and Syrian refugees are going to be analized on three-month period. As a result, Turkish public diplomacy and refugee relations and its implications on the international media in the context of Syrian refugees will be evaluated and some recommendations for the future of Turkish public diplomacy and refugee relations will be provided.
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Brighide M. Lynch
2015-05-01
Full Text Available Background: In 2010 a community of practice was set up for and by doctoral students engaged in person-centred and practitioner research. After three years, this community became part of a larger international community of practice. Aims and objectives: Captured under the stanzas of a poem and supported by the literature, this paper uses member narratives and creative expressions in a critical reflection on the experience of being a member of the Student International Community of Practice. Conclusions: Membership in the community of practice was experienced as beneficial, providing both support and challenge to enrich the doctoral students’ development as person-centred researchers. Retaining connectivity across an international landscape and finding effective ways to integrate new members into the community presented the greatest challenges. Implications for practice development: • The theoretical foundation and experiential knowledge could assist others considering support structures for the development of person-centred practices • Shared learning and co-creation of knowledge add value to the experience of being a doctoral researcher • Membership fluctuations present challenges to continuity of learning and the maintenance of a safe space with communities of practice. Such fluctuations, however, create chances for community members to experience diverse roles within the group and encourage explicit attention to person-centredness
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Raúl Hernán Contreras Román
2015-12-01
Full Text Available The present article develops an initial discussion on the persistence of the peasant class in anthropology as an awkward object, which since it has become asubject for the discipline has obliged anthropologists to re-examine their disciplinary identity and re-think their theoretical bases. We start from the idea that both the emergence and the decline of peasant studies in the discipline have corresponded with localizable social, intellectual and political contexts. For this reason we present the current struggle of peasant internationalism, represented by the international movement Vía Campesina, for food sovereignty and international recognition of the rights of peasant men and women. These struggles are considered to constitute a politically novel space which has the potential to generate political opportunities for peasant claims in the face of neoliberal despoliation. Finally, we reflect on how these struggles again present the peasant class as an awkward object for anthropology and demand anthropological discussion of the subject.
Energy Technology Data Exchange (ETDEWEB)
Lopuski, J
1994-12-31
This book deals with deals of the complex issues of liability and compensation for nuclear damage which have been considered in the course of the work of the IAEA concerning the revision of the Vienna Convention on nuclear liability. It presents, in an orderly way, personal reflections of its author based on his experience gathered in years 1989-1992 when participating in this work. Necessarily it contains in some of its parts references to documents of the IAEA Standing Committee on Nuclear Liability; these documents because of their length could not be reproduced. Consequently these parts may not be fully intelligible for those who have not participated in or closely followed the Committee`s work. The IAEA work on liability for nuclear damage was initiated in the wake of the impact made on the world`s public opinion by the Chernobyl incident and its transboundary effects; issues of international state liability and full compensation have been raised. But humanitarian ideas have quickly been confronted with cold calculations of the cost of financial protection for victims and an open unwillingness of some nuclear states has been manifested. After three years of discussions no wide consensus could be reached on some basic issues, such as: relationship between international state and civil liability regimes, structure of international legislation, concept of nuclear damage, limits of compensation, role of public funds or jurisdiction. The author presents his approach to these controversial issue, trying to provide at the same time a theoretical outline for the future international legislation on nuclear liability. (author).
Energy Technology Data Exchange (ETDEWEB)
Lopuski, J.
1993-12-31
This book deals with deals of the complex issues of liability and compensation for nuclear damage which have been considered in the course of the work of the IAEA concerning the revision of the Vienna Convention on nuclear liability. It presents, in an orderly way, personal reflections of its author based on his experience gathered in years 1989-1992 when participating in this work. Necessarily it contains in some of its parts references to documents of the IAEA Standing Committee on Nuclear Liability; these documents because of their length could not be reproduced. Consequently these parts may not be fully intelligible for those who have not participated in or closely followed the Committee`s work. The IAEA work on liability for nuclear damage was initiated in the wake of the impact made on the world`s public opinion by the Chernobyl incident and its transboundary effects; issues of international state liability and full compensation have been raised. But humanitarian ideas have quickly been confronted with cold calculations of the cost of financial protection for victims and an open unwillingness of some nuclear states has been manifested. After three years of discussions no wide consensus could be reached on some basic issues, such as: relationship between international state and civil liability regimes, structure of international legislation, concept of nuclear damage, limits of compensation, role of public funds or jurisdiction. The author presents his approach to these controversial issue, trying to provide at the same time a theoretical outline for the future international legislation on nuclear liability. (author).
DEFF Research Database (Denmark)
Parhamifar, Ladan; Moghimi, Seyed Moien
2012-01-01
Nanoparticulate systems are widely used for site-specific drug and gene delivery as well as for medical imaging. The mode of nanoparticle-cell interaction may have a significant effect on the pathway of nanoparticle internalization and subsequent intracellular trafficking. Total internal reflection...
Label free imaging of cell-substrate contacts by holographic total internal reflection microscopy.
Mandracchia, Biagio; Gennari, Oriella; Marchesano, Valentina; Paturzo, Melania; Ferraro, Pietro
2017-09-01
The study of cell adhesion contacts is pivotal to understand cell mechanics and interaction at substrates or chemical and physical stimuli. We designed and built a HoloTIR microscope for label-free quantitative phase imaging of total internal reflection. Here we show for the first time that HoloTIR is a good choice for label-free study of focal contacts and of cell/substrate interaction as its sensitivity is enhanced in comparison with standard TIR microscopy. Finally, the simplicity of implementation and relative low cost, due to the requirement of less optical components, make HoloTIR a reasonable alternative, or even an addition, to TIRF microscopy for mapping cell/substratum topography. As a proof of concept, we studied the formation of focal contacts of fibroblasts on three substrates with different levels of affinity for cell adhesion. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Benchmarking of HEU mental annuli critical assemblies with internally reflected graphite cylinder
Directory of Open Access Journals (Sweden)
Xiaobo Liu
2017-01-01
Full Text Available Three experimental configurations of critical assemblies, performed in 1963 at the Oak Ridge Critical Experiment Facility, which are assembled using three different diameter HEU annuli (15-9 inches, 15-7 inches and 13-7 inches metal annuli with internally reflected graphite cylinder are evaluated and benchmarked. The experimental uncertainties which are 0.00057, 0.00058 and 0.00057 respectively, and biases to the benchmark models which are − 0.00286, − 0.00242 and − 0.00168 respectively, were determined, and the experimental benchmark keff results were obtained for both detailed and simplified models. The calculation results for both detailed and simplified models using MCNP6-1.0 and ENDF/B-VII.1 agree well to the benchmark experimental results within difference less than 0.2%. The benchmarking results were accepted for the inclusion of ICSBEP Handbook.
Chen, Youhua; Cao, Ruizhi; Liu, Wenjie; Zhu, Dazhao; Zhang, Zhiming; Kuang, Cuifang; Liu, Xu
2018-04-01
We present an alternative approach to realize structured illumination microscopy (SIM), which is capable for live cell imaging. The prototype utilizes two sets of scanning galvo mirrors, a polarization converter and a piezo-platform to generate a fast shifted, s-polarization interfered and periodic variable illumination patterns. By changing the angle of the scanning galvanometer, we can change the position of the spots at the pupil plane of the objective lens arbitrarily, making it easy to switch between widefield and total internal reflection fluorescent-SIM mode and adapting the penetration depth in the sample. Also, a twofold resolution improvement is achieved in our experiments. The prototype offers more flexibility of pattern period and illumination orientation changing than previous systems.
Goudsmits, Joris M H; van Oijen, Antoine M; Slotboom, Dirk J
2017-01-01
Cells are delineated by a lipid bilayer that physically separates the inside from the outer environment. Most polar, charged, or large molecules require proteins to reduce the energetic barrier for passage across the membrane and to achieve transport rates that are relevant for life. Here, we describe techniques to visualize the functioning of membrane transport proteins with fluorescent probes at the single-molecule level. First, we explain how to produce membrane-reconstituted transporters with fluorescent labels. Next, we detail the construction of a microfluidic flow cell to image immobilized proteoliposomes on a total internal reflection fluorescence microscope. We conclude by describing the methods that are needed to analyze fluorescence movies and obtain useful single-molecule data. © 2017 Elsevier Inc. All rights reserved.
Registration of T-2 mycotoxin with total internal reflection ellipsometry and QCM impedance methods.
Nabok, A V; Tsargorodskaya, A; Holloway, A; Starodub, N F; Gojster, O
2007-01-15
A sensitive optical method of total internal reflection ellipsometry (TIRE) in conjunction with immune assay approach was exploited for the registration of T-2 mycotoxin in a wide range of concentrations from 100 microg/ml down to 0.15 ng/ml. Association constants of 1.4x10(6) and 1.9x10(7)mol(-1)s for poly- and monoclonal T-2 antibodies, respectively, were evaluated from TIRE kinetic measurements. According to TIRE data fitting, binding of T-2 molecules to antibodies (at saturation) has resulted in the increase in adsorbed layer thickness of 4-5 nm. The QCM impedance measurements data showed anomalously large mass increase and film softening, most likely, due to the binding of large T-2 aggregates to antibodies.
Imaging Early Steps of Sindbis Virus Infection by Total Internal Reflection Fluorescence Microscopy
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Youling Gu
2011-01-01
Full Text Available Sindbis virus (SINV is an alphavirus that has a broad host range and has been widely used as a vector for recombinant gene transduction, DNA-based vaccine production, and oncolytic cancer therapy. The mechanism of SINV entry into host cells has yet to be fully understood. In this paper, we used single virus tracking under total internal reflection fluorescence microscopy (TIRFM to investigate SINV attachment to cell surface. Biotinylated viral particles were labeled with quantum dots, which retained viral viability and infectivity. By time-lapse imaging, we showed that the SINV exhibited a heterogeneous dynamics on the surface of the host cells. Analysis of SINV motility demonstrated a two-step attachment reaction. Moreover, dual color TIRFM of GFP-Rab5 and SINV suggested that the virus was targeted to the early endosomes after endocytosis. These findings demonstrate the utility of quantum dot labeling in studying the early steps and behavior of SINV infection.
Watch your step! A frustrated total internal reflection approach to forensic footwear imaging.
Needham, J A; Sharp, J S
2016-02-16
Forensic image retrieval and processing are vital tools in the fight against crime e.g. during fingerprint capture. However, despite recent advances in machine vision technology and image processing techniques (and contrary to the claims of popular fiction) forensic image retrieval is still widely being performed using outdated practices involving inkpads and paper. Ongoing changes in government policy, increasing crime rates and the reduction of forensic service budgets increasingly require that evidence be gathered and processed more rapidly and efficiently. A consequence of this is that new, low-cost imaging technologies are required to simultaneously increase the quality and throughput of the processing of evidence. This is particularly true in the burgeoning field of forensic footwear analysis, where images of shoe prints are being used to link individuals to crime scenes. Here we describe one such approach based upon frustrated total internal reflection imaging that can be used to acquire images of regions where shoes contact rigid surfaces.
Watch your step! A frustrated total internal reflection approach to forensic footwear imaging
Needham, J. A.; Sharp, J. S.
2016-02-01
Forensic image retrieval and processing are vital tools in the fight against crime e.g. during fingerprint capture. However, despite recent advances in machine vision technology and image processing techniques (and contrary to the claims of popular fiction) forensic image retrieval is still widely being performed using outdated practices involving inkpads and paper. Ongoing changes in government policy, increasing crime rates and the reduction of forensic service budgets increasingly require that evidence be gathered and processed more rapidly and efficiently. A consequence of this is that new, low-cost imaging technologies are required to simultaneously increase the quality and throughput of the processing of evidence. This is particularly true in the burgeoning field of forensic footwear analysis, where images of shoe prints are being used to link individuals to crime scenes. Here we describe one such approach based upon frustrated total internal reflection imaging that can be used to acquire images of regions where shoes contact rigid surfaces.
Allgeyer, Edward S; Sterling, Sarah M; Gunewardene, Mudalige S; Hess, Samuel T; Neivandt, David J; Mason, Michael D
2015-01-27
Understanding surface and interfacial lateral organization in material and biological systems is critical in nearly every field of science. The continued development of tools and techniques viable for elucidation of interfacial and surface information is therefore necessary to address new questions and further current investigations. Sum frequency spectroscopy (SFS) is a label-free, nonlinear optical technique with inherent surface specificity that can yield critical organizational information on interfacial species. Unfortunately, SFS provides no spatial information on a surface; small scale heterogeneities that may exist are averaged over the large areas typically probed. Over the past decade, this has begun to be addressed with the advent of SFS microscopy. Here we detail the construction and function of a total internal reflection (TIR) SFS spectral and confocal fluorescence imaging microscope directly amenable to surface investigations. This instrument combines, for the first time, sample scanning TIR-SFS imaging with confocal fluorescence microscopy.
Common-path configuration in total internal reflection digital holography microscopy.
Calabuig, Alejandro; Matrecano, Marcella; Paturzo, Melania; Ferraro, Pietro
2014-04-15
Total Internal Reflection Digital Holographic Microscopy (TIRDHM) is recognized to be a powerful tool for retrieving quantitative phase images of cell-substrate interfaces, adhesions, and tissue structures close to the prism surface. In this Letter, we develop an improved TIRDHM system, taking advantage of a refractive index mismatch between the prism and the sample substrate, to allow phase-shifting DH with just a single-beam interferometric configuration. Instead of the traditional off-axis method, phase-shift method is used to retrieve amplitude and phase images in coherent light and TIR modality. Essentially, the substrate-prism interface acts like a beam splitter generating a reference beam, where the phase-shift dependence on the incident angle is exploited in this common-path configuration. With the aim to demonstrate the technique's validity, some experiments are performed to establish the advantage of this compact and simple configuration, in which the reference arm in the setup is avoided.
Analysis of thin-film polymers using attenuated total internal reflection-Raman microspectroscopy.
Tran, Willie; Tisinger, Louis G; Lavalle, Luis E; Sommer, André J
2015-01-01
Two methods commonly employed for molecular surface analysis and thin-film analysis of microscopic areas are attenuated total reflection infrared (ATR-IR) microspectroscopy and confocal Raman microspectroscopy. In the former method, the depth of the evanescent probe beam can be controlled by the wavelength of light, the angle of incidence, or the refractive index of the internal reflection element. Because the penetration depth is proportional to the wavelength of light, one could interrogate a smaller film thickness by moving from the mid-infrared region to the visible region employing Raman spectroscopy. The investigation of ATR Raman microspectroscopy, a largely unexplored technique available to Raman microspectroscopy, was carried out. A Renishaw inVia Raman microscope was externally modified and used in conjunction with a solid immersion lens (SIL) to perform ATR Raman experiments. Thin-film polymer samples were analyzed to explore the theoretical sampling depth for experiments conducted without the SIL, with the SIL, and with the SIL using evanescent excitation. The feasibility of micro-ATR Raman was examined by collecting ATR spectra from films whose thickness measured from 200 to 60 nm. Films of these thicknesses were present on a much thicker substrate, and features from the underlying substrate did not become visible until the thin film reached a thickness of 68 nm.
Near IR Scanning Angle Total Internal Reflection Raman Spectroscopy at Smooth Gold Films
Energy Technology Data Exchange (ETDEWEB)
McKee, Kristopher; Meyer, Matthew; Smith, Emily
2012-04-13
Total internal reflection (TIR) Raman and reflectivity spectra were collected for nonresonant analytes as a function of incident angle at sapphire or sapphire/smooth 50 nm gold interfaces using 785 nm excitation. For both interfaces, the Raman signal as a function of incident angle is well-modeled by the calculated interfacial mean square electric field (MSEF) relative to the incident field times the thickness of the layer being probed in the Raman measurement (D{sub RS}). The Raman scatter was reproducibly enhanced at the interface containing a gold film relative to the sapphire interface by a factor of 4.3–4.6 for aqueous pyridine or 2.2–3.7 for neat nitrobenzene, depending on the analyzed vibrational mode. The mechanism for the increased Raman signal is the enhanced MSEF at incident angles where propagating surface plasmons are excited in the metal film. The background from the TIR prism was reduced by 89–95% with the addition of the gold film, and the percent relative uncertainty in peak area was reduced from 15 to 1.7% for the 1347 cm–1 mode of nitrobenzene. Single monolayers of benzenethiol (S/N = 6.8) and 4-mercaptopyridine (S/N = 16.5) on gold films were measured by TIR Raman spectroscopy with 785 nm excitation (210 mW) without resonant enhancement in 1 min.
Unusual conversations: A reflection on the mechanics of internationally engaged public scholarship
Directory of Open Access Journals (Sweden)
Jonathan Damiani
2016-09-01
Full Text Available This article analyses the civic engagement pathways of researchers from the Asia-Pacific and the United States in an effort to see how the principles of what American scholars consider publicly engaged research and creative practice are being enacted in research sites across the globe. The purpose of this ongoing project is to focus on finding ways of connecting American scholars with a network of higher education and research institutions that hold a commitment and passion for social responsibility and civic engagement as it impacts education, research and service for community development overseas. The narrative includes the voices and perspectives of colleagues dedicated to engaged scholarship from across the new region in which I work (the Asia-Pacific, alongside the voices of some of Imagining America’s (IA 2014 National Conference participants. These conversations serve as a critical reflection on the mechanics of doing public scholarship overseas and frame a new model of internationally engaged scholarship. Keywords: Internationally engaged public scholarship, unusual conversations
Transformational plane geometry
Umble, Ronald N
2014-01-01
Axioms of Euclidean Plane Geometry The Existence and Incidence Postulates The Distance and Ruler Postulates The Plane Separation Postulate The Protractor Postulate The Side-Angle-Side Postulate and the Euclidean Parallel Postulate Theorems of Euclidean Plane Geometry The Exterior Angle Theorem Triangle Congruence Theorems The Alternate Interior Angles Theorem and the Angle Sum Theorem Similar Triangles Introduction to Transformations, Isometries, and Similarities Transformations Isometries and SimilaritiesAppendix: Proof of Surjectivity Translations, Rotations, and Reflections Translations Rotations Reflections Appendix: Geometer's Sketchpad Commands Required by Exploratory Activities Compositions of Translations, Rotations, and Reflections The Three Points Theorem Rotations as Compositions of Two Reflections Translations as Compositions of Two Halfturns or Two Reflections The Angle Addition Theorem Glide Reflections Classification of Isometries The Fundamental Theorem and Congruence Classification of Isometr...
Iversen, Birger
1992-01-01
Although it arose from purely theoretical considerations of the underlying axioms of geometry, the work of Einstein and Dirac has demonstrated that hyperbolic geometry is a fundamental aspect of modern physics
van den Broek, P.M.
1984-01-01
The aim of this paper is to give a detailed exposition of the relation between the geometry of twistor space and the geometry of Minkowski space. The paper has a didactical purpose; no use has been made of differential geometry and cohomology.
Gong, Xiangjun; Hua, Li; Wu, Chi; Ngai, To
2013-03-01
We present a novel microrheometer by incorporating magnetic tweezers in the total internal reflection microscopy (TIRM) that enables measuring of viscoelastic properties of materials near solid surface. An evanescent wave generated by a solid∕liquid interface in the TIRM is used as the incident light source in the microrheometer. When a probe particle (of a few micrometers diameter) moves near the interface, it can interact with the evanescent field and reflect its position with respect to the interface by the scattered light intensity. The exponential distance dependence of the evanescent field, on the one hand, makes this technique extremely sensitive to small changes from z-fluctuations of the probe (with a resolution of several nanometers), and on the other, it does not require imaging of the probe with high lateral resolution. Another distinct advantage is the high sensitivity in determining the z position of the probe in the absence of any labeling. The incorporated magnetic tweezers enable us to effectively manipulate the distance of the embedded particle from the interface either by a constant or an oscillatory force. The force ramp is easy to implement through a coil current ramp. In this way, the local viscous and elastic properties of a given system under different confinements can therefore be measured by resolving the near-surface particle motion. To test the feasibility of applying this microrheology to soft materials, we measured the viscoelastic properties of sucrose and poly(ethylene glycol) solutions and compared the results to bulk rheometry. In addition, we applied this technique in monitoring the structure and properties of deformable microgel particles near the flat surface.
Tabachnikov, Serge
2005-01-01
Mathematical billiards describe the motion of a mass point in a domain with elastic reflections off the boundary or, equivalently, the behavior of rays of light in a domain with ideally reflecting boundary. From the point of view of differential geometry, the billiard flow is the geodesic flow on a manifold with boundary. This book is devoted to billiards in their relation with differential geometry, classical mechanics, and geometrical optics. The topics covered include variational principles of billiard motion, symplectic geometry of rays of light and integral geometry, existence and nonexistence of caustics, optical properties of conics and quadrics and completely integrable billiards, periodic billiard trajectories, polygonal billiards, mechanisms of chaos in billiard dynamics, and the lesser-known subject of dual (or outer) billiards. The book is based on an advanced undergraduate topics course (but contains more material than can be realistically taught in one semester). Although the minimum prerequisit...
Directory of Open Access Journals (Sweden)
Hardre PL
2017-01-01
Full Text Available Patricia L Hardré,1 Mikio Nihira,2 Edgar L LeClaire3 1Department of Educational Psychology, University of Oklahoma College of Education, Norman, 2Department of Obstetrics and Gynecology, University of Oklahoma College of Medicine, Oklahoma City, OK, 3Department of Obstetrics and Gynecology, University of Kansas College of Medicine, Kansas City, KS, USA Abstract: Research in medical education does not provide a clear understanding of how professional expertise develops among surgeons and what experiential factors contribute to that development. To address this gap, the researchers interviewed 16 international experts in female pelvic medicine and reconstructive surgery to assess their reflective perceptions of what specific opportunities and experiences initiated and supported their development toward expertise in their field. Characteristics and influences explaining the speed and quality of expertise development were sorted into the following themes: the dynamic process of expertise development, internal and personal characteristics, general aptitudes and preparatory skills, role modeling and interpersonal influences, opportunities to learn and practice, and roles and reference points. Across the narratives and perspectives of these expert surgeons, both individual characteristics and choices, and contextual activities and opportunities were necessary and important. Experiences with greatest impact on quality of expertise development included those provided by the environment and mentors, as well as those sought out by learners themselves, to elaborate and supplement existing opportunities. The ideal combination across experts was interaction and integration of individual characteristics with experiential opportunities. Grounded in theory and research in expertise development, these findings can support improvement of medical education, both for individual mentors and strategic program development. As surgery evolves at a continuously
International Nuclear Information System (INIS)
Zhu, Peifen
2016-01-01
The light extraction efficiency of top-emitting organic light-emitting diodes (OLEDs) is numerically investigated employing the finite-difference time-domain method. The periodic nanostructures formed by embedding the sphere arrays in polystyrene (PS) are placed on top of OLED to frustrate the total internal reflection at the interface between OLED and free space. These nanostructures serve as an intermediate medium to extract the light out of OLED devices. Efficiently coupling both evanescent waves and propagation waves into spheres and subsequently extracting these light waves out of the sphere is key to achieving high extraction efficiency. By tuning the thickness of PS layer, both of the in-coupling efficiency and out-coupling efficiency are optimized for achieving high light extraction efficiency. Thicker PS layer results in higher in-coupling efficiency in sphere while the thinner PS layer leads to higher out-coupling efficiency. Thus the maximum light extraction is a trade-off between the in-coupling efficiency and out-coupling efficiency. The study shows that light extraction efficiency of 89% can be achieved by embedding 0.90 μm TiO 2 sphere in 0.30 μm PS layer with optimized in-coupling efficiency, out-coupling efficiency and cavity effect. (paper)
Accessible biometrics: A frustrated total internal reflection approach to imaging fingerprints.
Smith, Nathan D; Sharp, James S
2017-05-01
Fingerprints are widely used as a means of identifying persons of interest because of the highly individual nature of the spatial distribution and types of features (or minuta) found on the surface of a finger. This individuality has led to their wide application in the comparison of fingerprints found at crime scenes with those taken from known offenders and suspects in custody. However, despite recent advances in machine vision technology and image processing techniques, fingerprint evidence is still widely being collected using outdated practices involving ink and paper - a process that can be both time consuming and expensive. Reduction of forensic service budgets increasingly requires that evidence be gathered and processed more rapidly and efficiently. However, many of the existing digital fingerprint acquisition devices have proven too expensive to roll out on a large scale. As a result new, low-cost imaging technologies are required to increase the quality and throughput of the processing of fingerprint evidence. Here we describe an inexpensive approach to digital fingerprint acquisition that is based upon frustrated total internal reflection imaging. The quality and resolution of the images produced are shown to be as good as those currently acquired using ink and paper based methods. The same imaging technique is also shown to be capable of imaging powdered fingerprints that have been lifted from a crime scene using adhesive tape or gel lifters. Copyright © 2017 The Chartered Society of Forensic Sciences. Published by Elsevier B.V. All rights reserved.
Boehm, E M; Subramanyam, S; Ghoneim, M; Washington, M Todd; Spies, M
2016-01-01
Large, dynamic macromolecular complexes play essential roles in many cellular processes. Knowing how the components of these complexes associate with one another and undergo structural rearrangements is critical to understanding how they function. Single-molecule total internal reflection fluorescence (TIRF) microscopy is a powerful approach for addressing these fundamental issues. In this article, we first discuss single-molecule TIRF microscopes and strategies to immobilize and fluorescently label macromolecules. We then review the use of single-molecule TIRF microscopy to study the formation of binary macromolecular complexes using one-color imaging and inhibitors. We conclude with a discussion of the use of TIRF microscopy to examine the formation of higher-order (i.e., ternary) complexes using multicolor setups. The focus throughout this article is on experimental design, controls, data acquisition, and data analysis. We hope that single-molecule TIRF microscopy, which has largely been the province of specialists, will soon become as common in the tool box of biophysicists and biochemists as structural approaches have become today. © 2016 Elsevier Inc. All rights reserved.
Nabok, Alexei; Tsargorodskaya, Anna; Davis, Frank; Higson, Séamus P J
2007-10-31
The adsorption of genomic DNA and subsequent interactions between adsorbed and solvated DNA was studied using a novel sensitive optical method of total internal reflection ellipsometry (TIRE), which combines spectroscopic ellipsometry with surface plasmon resonance (SPR). Single strands of DNA of two species of fish (herring and salmon) were electrostatically adsorbed on top of polyethylenimine films deposited upon gold coated glass slides. The ellipsometric spectra were recorded and data fitting utilized to extract optical parameters (thickness and refractive index) of adsorbed DNA layers. The further adsorption of single stranded DNA from an identical source, i.e. herring ss-DNA on herring ss-DNA or salmon ss-DNA on salmon ss-DNA, on the surface was observed to give rise to substantial film thickness increases at the surface of about 20-21 nm. Conversely adsorption of DNA from alternate species, i.e. salmon ss-DNA on herring ss-DNA or herring ss-DNA on salmon ss-DNA, yielded much smaller changes in thickness of 3-5 nm. AFM studies of the surface roughness of adsorbed layers were in line with the TIRE data.
New light on ion channel imaging by total internal reflection fluorescence (TIRF) microscopy.
Yamamura, Hisao; Suzuki, Yoshiaki; Imaizumi, Yuji
2015-05-01
Ion channels play pivotal roles in a wide variety of cellular functions; therefore, their physiological characteristics, pharmacological responses, and molecular structures have been extensively investigated. However, the mobility of an ion channel itself in the cell membrane has not been examined in as much detail. A total internal reflection fluorescence (TIRF) microscope allows fluorophores to be imaged in a restricted region within an evanescent field of less than 200 nm from the interface of the coverslip and plasma membrane in living cells. Thus the TIRF microscope is useful for selectively visualizing the plasmalemmal surface and subplasmalemmal zone. In this review, we focused on a single-molecule analysis of the dynamic movement of ion channels in the plasma membrane using TIRF microscopy. We also described two single-molecule imaging techniques under TIRF microscopy: fluorescence resonance energy transfer (FRET) for the identification of molecules that interact with ion channels, and subunit counting for the determination of subunit stoichiometry in a functional channel. TIRF imaging can also be used to analyze spatiotemporal Ca(2+) events in the subplasmalemma. Single-molecule analyses of ion channels and localized Ca(2+) signals based on TIRF imaging provide beneficial pharmacological and physiological information concerning the functions of ion channels. Copyright © 2015 The Authors. Production and hosting by Elsevier B.V. All rights reserved.
Directory of Open Access Journals (Sweden)
Yoshihiro Kawano
Full Text Available Whole slide imaging (WSI is a useful tool for multi-modal imaging, and in our work, we have often combined WSI with darkfield microscopy. However, traditional darkfield microscopy cannot use a single condenser to support high- and low-numerical-aperture objectives, which limits the modality of WSI. To overcome this limitation, we previously developed a darkfield internal reflection illumination (DIRI microscope using white light-emitting diodes (LEDs. Although the developed DIRI is useful for biological applications, substantial problems remain to be resolved. In this study, we propose a novel illumination technique called color DIRI. The use of three-color LEDs dramatically improves the capability of the system, such that color DIRI (1 enables optimization of the illumination color; (2 can be combined with an oil objective lens; (3 can produce fluorescence excitation illumination; (4 can adjust the wavelength of light to avoid cell damage or reactions; and (5 can be used as a photostimulator. These results clearly illustrate that the proposed color DIRI can significantly extend WSI modalities for biological applications.
International Nuclear Information System (INIS)
Dunklin, Jeremy R; Keith Roper, D; Forcherio, Gregory T
2015-01-01
Optical properties of polymer films embedded with plasmonic nanoparticles (NPs) are important in many implementations. In this work, optical extinction by polydimethylsiloxane (PDMS) films containing gold (Au) NPs was enhanced at resonance compared to AuNPs in suspensions, Beer–Lambert law, or Mie theory by internal reflection due to optical diffraction in 16 nm AuNP–PDMS films and Mie scattering in 76 nm AuNP–PDMS films. Resonant extinction per AuNP for 16 nm AuNPs with negligible resonant Mie scattering was enhanced up to 1.5-fold at interparticle separation (i.e., Wigner–Seitz radii) comparable to incident wavelength. It was attributable to diffraction through apertures formed by overlapping electric fields of adjacent, resonantly excited AuNPs at Wigner–Seitz radii equal to or less than incident wavelengths. Resonant extinction per AuNP for strongly Mie scattering 76 nm AuNPs was enhanced up to 1.3-fold at Wigner–Seitz radii four or more times greater than incident wavelength. Enhanced light trapping from diffraction and/or scattering is relevant to optoelectronic, biomedical, and catalytic activity of substrates embedded with NPs. (paper)
Gulley-Stahl, Heather J; Haas, Jennifer A; Schmidt, Katherine A; Evan, Andrew P; Sommer, André J
2009-07-01
The impact of kidney stone disease is significant worldwide, yet methods for quantifying stone components remain limited. A new approach requiring minimal sample preparation for the quantitative analysis of kidney stone components has been investigated utilizing attenuated total internal reflection Fourier transform infrared spectroscopy (ATR-FT-IR). Calcium oxalate monohydrate (COM) and hydroxylapatite (HAP), two of the most common constituents of urinary stones, were used for quantitative analysis. Calibration curves were constructed using integrated band intensities of four infrared absorptions versus concentration (weight %). The correlation coefficients of the calibration curves range from 0.997 to 0.93. The limits of detection range from 0.07 +/- 0.02% COM/HAP where COM is the analyte and HAP is the matrix, to 0.26 +/- 0.07% HAP/COM where HAP is the analyte and COM is the matrix. This study shows that linear calibration curves can be generated for the quantitative analysis of stone mixtures provided the system is well understood especially with respect to particle size.
Rodger, Alison
1995-01-01
Molecular Geometry discusses topics relevant to the arrangement of atoms. The book is comprised of seven chapters that tackle several areas of molecular geometry. Chapter 1 reviews the definition and determination of molecular geometry, while Chapter 2 discusses the unified view of stereochemistry and stereochemical changes. Chapter 3 covers the geometry of molecules of second row atoms, and Chapter 4 deals with the main group elements beyond the second row. The book also talks about the complexes of transition metals and f-block elements, and then covers the organometallic compounds and trans
Le Cornu, Alison
2009-01-01
The study of the process of reflection has a dignified history. However, few have linked reflection to the development of the self in such a way that the form of reflection is understood to influence the resultant type of self. This article explores the process of reflection using a framework of meaning making, internalization, and externalization…
Ng, Vinci; Yuen, Mantak
2015-01-01
This paper reflects upon the relevance of Buddhism to counselling in general and to career counseling in particular by discussing a program implemented at an international school in Hong Kong. The authors provide an analysis of the pertinent literature related to relevant concepts within Buddhism. This topic has not yet been adequately researched…
Cardoso Dos Santos, Marcelina; Vézy, Cyrille; Jaffiol, Rodolphe
2016-02-01
Total Internal Reflection Fluorescence Microscopy (TIRFM) is a widespread technique to study cellular process occurring near the contact region with the glass substrate. In this field, determination of the accurate distance from the surface to the plasma membrane constitutes a crucial issue to investigate the physical basis of cellular adhesion process. However, quantitative interpretation of TIRF pictures regarding the distance z between a labeled membrane and the substrate is not trivial. Indeed, the contrast of TIRF images depends on several parameters more and less well known (local concentration of dyes, absorption cross section, angular emission pattern…). The strategy to get around this problem is to exploit a series of TIRF pictures recorded at different incident angles in evanescent regime. This technique called variable-angle TIRF microscopy (vaTIRFM), allowing to map the membrane-substrate separation distance with a nanometric resolution (10-20 nm). vaTIRFM was developed by Burmeister, Truskey and Reichert in the early 1990s with a prism-based TIRF setup [Journal of Microscopy 173, 39-51 (1994)]. We propose a more convenient prismless setup, which uses only a rotatable mirror to adjust precisely the laser beam on the back focal plane of the oil immersion objective (no azimuthal scanning is needed). The series of TIRF images permit us to calculate accurately membrane-surface distances in each pixel. We demonstrate that vaTIRFM are useful to quantify the adhesion of living cells for specific and unspecific membrane-surface interactions, achieved on various functionalized substrates with polymers (BSA, poly-L-lysin) or extracellular matrix proteins (collagen and fibronectin).
Attenuated total internal reflection infrared microscopy of multilayer plastic packaging foils.
van Dalen, Gerard; Heussen, Patricia C M; den Adel, Ruud; Hoeve, Robert B J
2007-06-01
Multilayer plastic foils are important packaging materials that are used to extend the shelf life of food products and drinks. Fourier transform infrared (FT-IR) spectroscopic imaging using attenuated total internal reflection (ATR) can be used for the identification and localization of different layers in multilayer foils. A new type of ATR crystal was used in combination with a linear array detector through which large sample areas (400 x 400 microm(2)) could be imaged with a pixel size of 1.6 microm. The method was tested on laminated plastic packing materials containing 5 to 12 layers. The results of the identification of the different materials using ATR-FT-IR were compared with differential scanning calorimetry (DSC) and the layer thickness of the individual layers measured by ATR-FT-IR was compared with polarized light microscopy (LM) and scanning electron microscopy (SEM). It has been demonstrated that individual layers with a thickness of about 3 microm could be identified in multilayer foils with a total thickness ranging from 100 to 150 microm. The results show a spatial resolution of about 4 microm (measured at wavenumbers ranging from 1000 to 1730 cm(-1)), which is about a factor of two better than can be obtained using transmission FT-IR imaging. An additional advantage of ATR is the ease of sample preparation. A good correspondence was found between visible and FT-IR images. The results of ATR-FT-IR imaging were in agreement with those obtained by LM, SEM, and DSC. ATR-FT-IR is superior to the combination of these techniques because it delivers both spatial and chemical information.
International Nuclear Information System (INIS)
Robinson, I.; Trautman, A.
1988-01-01
The geometry of classical physics is Lorentzian; but weaker geometries are often more appropriate: null geodesics and electromagnetic fields, for example, are well known to be objects of conformal geometry. To deal with a single null congruence, or with the radiative electromagnetic fields associated with it, even less is needed: flag geometry for the first, optical geometry, with which this paper is chiefly concerned, for the second. The authors establish a natural one-to-one correspondence between optical geometries, considered locally, and three-dimensional Cauchy-Riemann structures. A number of Lorentzian geometries are shown to be equivalent from the optical point of view. For example the Goedel universe, the Taub-NUT metric and Hauser's twisting null solution have an optical geometry isomorphic to the one underlying the Robinson congruence in Minkowski space. The authors present general results on the problem of lifting a CR structure to a Lorentz manifold and, in particular, to Minkowski space; and exhibit the relevance of the deviation form to this problem
Lepp, Margret; Zorn, CeCelia R.; Duffy, Patricia R.; Dickson, Rana J.
2003-01-01
A nursing course connected U.S. and Swedish sites via interactive videoconferencing and used reflective methods (journaling, drama, photo language) and off-air group discussion. Evaluation by five Swedish and seven U.S. students suggested how reflection moved students toward greater authenticity and professionalism in nursing practice. (Contains…
International Nuclear Information System (INIS)
Roshan Entezar, S.
2015-01-01
The phase difference between two p-polarized and s-polarized plane waves which are reflected under total internal reflection from the base of a prism with a thin metal coating is studied. Typically such a quantity can be used to measure the refractive index of a test material using the total internal reflection method. It is shown that due to the excitation of surface plasmon polaritons at the interface between the tested dielectric material and the thin metal layer, the p-polarized light experiences a large phase shift which enlarges the phase difference between the p-polarized and the s-polarized waves. As a result, the sensitivity of refractive index measurement increases and the error in determining the refractive index decreases. - Highlights: • Phase difference of totally internally reflected p and s polarized beams is studied. • Excitation of the surface wave increases the phase shift of the p-polarized light. • The sensitivity of refractive index measurement increases by using a coated prism. • The error in determining the refractive index decreases using the coated prism
Pottmann, Helmut; Eigensatz, Michael; Vaxman, Amir; Wallner, Johannes
2014-01-01
Around 2005 it became apparent in the geometry processing community that freeform architecture contains many problems of a geometric nature to be solved, and many opportunities for optimization which however require geometric understanding. This area of research, which has been called architectural geometry, meanwhile contains a great wealth of individual contributions which are relevant in various fields. For mathematicians, the relation to discrete differential geometry is significant, in particular the integrable system viewpoint. Besides, new application contexts have become available for quite some old-established concepts. Regarding graphics and geometry processing, architectural geometry yields interesting new questions but also new objects, e.g. replacing meshes by other combinatorial arrangements. Numerical optimization plays a major role but in itself would be powerless without geometric understanding. Summing up, architectural geometry has become a rewarding field of study. We here survey the main directions which have been pursued, we show real projects where geometric considerations have played a role, and we outline open problems which we think are significant for the future development of both theory and practice of architectural geometry.
Pottmann, Helmut
2014-11-26
Around 2005 it became apparent in the geometry processing community that freeform architecture contains many problems of a geometric nature to be solved, and many opportunities for optimization which however require geometric understanding. This area of research, which has been called architectural geometry, meanwhile contains a great wealth of individual contributions which are relevant in various fields. For mathematicians, the relation to discrete differential geometry is significant, in particular the integrable system viewpoint. Besides, new application contexts have become available for quite some old-established concepts. Regarding graphics and geometry processing, architectural geometry yields interesting new questions but also new objects, e.g. replacing meshes by other combinatorial arrangements. Numerical optimization plays a major role but in itself would be powerless without geometric understanding. Summing up, architectural geometry has become a rewarding field of study. We here survey the main directions which have been pursued, we show real projects where geometric considerations have played a role, and we outline open problems which we think are significant for the future development of both theory and practice of architectural geometry.
Beyond Reflection through an Academic Lens: Refraction and International Experiential Education
Pagano, Monica; Roselle, Laura
2009-01-01
Students today are becoming more interested in international opportunities for study, and are drawn to alternative programs such as international service learning and international internships. These programs, however, must be carefully designed. In this paper, the authors propose using tools that go beyond the traditional understanding of…
Maor, Eli
2014-01-01
If you've ever thought that mathematics and art don't mix, this stunning visual history of geometry will change your mind. As much a work of art as a book about mathematics, Beautiful Geometry presents more than sixty exquisite color plates illustrating a wide range of geometric patterns and theorems, accompanied by brief accounts of the fascinating history and people behind each. With artwork by Swiss artist Eugen Jost and text by acclaimed math historian Eli Maor, this unique celebration of geometry covers numerous subjects, from straightedge-and-compass constructions to intriguing configur
Kemnitz, Arnfried
Der Grundgedanke der Analytischen Geometrie besteht darin, dass geometrische Untersuchungen mit rechnerischen Mitteln geführt werden. Geometrische Objekte werden dabei durch Gleichungen beschrieben und mit algebraischen Methoden untersucht.
Lefschetz, Solomon
2005-01-01
An introduction to algebraic geometry and a bridge between its analytical-topological and algebraical aspects, this text for advanced undergraduate students is particularly relevant to those more familiar with analysis than algebra. 1953 edition.
Ay, Nihat; Lê, Hông Vân; Schwachhöfer, Lorenz
2017-01-01
The book provides a comprehensive introduction and a novel mathematical foundation of the field of information geometry with complete proofs and detailed background material on measure theory, Riemannian geometry and Banach space theory. Parametrised measure models are defined as fundamental geometric objects, which can be both finite or infinite dimensional. Based on these models, canonical tensor fields are introduced and further studied, including the Fisher metric and the Amari-Chentsov tensor, and embeddings of statistical manifolds are investigated. This novel foundation then leads to application highlights, such as generalizations and extensions of the classical uniqueness result of Chentsov or the Cramér-Rao inequality. Additionally, several new application fields of information geometry are highlighted, for instance hierarchical and graphical models, complexity theory, population genetics, or Markov Chain Monte Carlo. The book will be of interest to mathematicians who are interested in geometry, inf...
Smith, P Alex; Wang, Yaxin; Metcalfe, Ralph W; Sampaio, Luiz C; Timms, Daniel L; Cohn, William E; Frazier, O H
2018-03-01
A minimally invasive, partial-assist, intra-atrial blood pump has been proposed, which would unload the left ventricle with a flow path from the left atrium to the arterial system. Flow modulation is a common strategy for ensuring washout in the pump, but it can increase power consumption because it is typically achieved through motor-speed variation. However, if a pump's performance curve had the proper gradient, flow modulation could be realized passively. To achieve this goal, we propose a pump performance operating curve as an alternative to the more standard operating point. Mean-line theory was employed to generate an initial set of geometries that were then tested on a hydraulic test rig at ~20,000 r/min. Experimental results show that the intra-atrial blood pump performed below the operating region; however, it was determined that smaller hub diameter and longer chord length bring the performance of the intra-atrial blood pump device closer to the operating curve. We found that it is possible to shape the pump performance curve for specifically targeted gradients over the operating region through geometric variations inside the pump.
International Nuclear Information System (INIS)
Guillemot, M.; Colomb, G.
1985-01-01
A series of criticality benchmark experiments with a small LWR-type core, reflected by 30 cm of lead, was defined jointly by SEC (Service d'Etude de Criticite), Fontenay-aux-Roses, and SRD (Safety and Reliability Directorate). These experiments are very representative of the reflecting effect of lead, since the contribution of the lead to the reactivity was assessed as about 30% in Δ K. The experiments were carried out by SRSC (Service de Recherche en Surete et Criticite), Valduc, in December 1983 in the sub-critical facility called APPARATUS B. In addition, they confirmed and measured the effect on reactivity of a water gap between the core and the lead reflector; with a water gap of less than 1 cm, the reactivity can be greater than that of the core directly reflected the lead or by over 20 cm of water. The experimental results were to a large extent made use of by SRD with the aid of the MONK Monte Carlo code and to some extent by SEC with the aid of the MORET Monte Carlo Code. All the results obtained are presented in the summary tables. These experiments allowed to compare the different libraries of cross sections available
Bathe-Peters, M; Annibale, P; Lohse, M J
2018-02-05
Microscopic imaging at high spatial-temporal resolution over long time scales (minutes to hours) requires rapid and precise stabilization of the microscope focus. Conventional and commercial autofocus systems are largely based on piezoelectric stages or mechanical objective actuators. Objective to sample distance is either measured by image analysis approaches or by hardware modules measuring the intensity of reflected infrared light. We propose here a truly all-optical microscope autofocus taking advantage of an electrically tunable lens and a totally internally reflected infrared probe beam. We implement a feedback-loop based on the lateral position of a totally internally reflected infrared laser on a quadrant photodetector, as an indicator of the relative defocus. We show here how to treat the combined contributions due to mechanical defocus and deformation of the tunable lens. As a result, the sample can be kept in focus without any mechanical movement, at rates up to hundreds of Hertz. The device requires only reflective optics and can be implemented at a fraction of the cost required for a comparable piezo-based actuator.
A plastic total internal reflection-based photoluminescence device for enzymatic biosensors
Thakkar, Ishan G.
Growing concerns for quality of water, food and beverages in developing and developed countries drive sizeable markets for mass-producible, low cost devices that can measure the concentration of contaminant chemicals in water, food, and beverages rapidly and accurately. Several fiber-optic enzymatic biosensors have been reported for these applications, but they exhibit very strong presence of scattered excitation light in the signal for sensing, requiring expensive thin-film filters, and their non-planar structure makes them challenging to mass-produce. Several other planar optical waveguide-based biosensors prove to be relatively costly and more fragile due to constituent materials and the techniques involved in their fabrication. So, a plastic total internal reflection (TIR)-based low cost, low scatter, field-portable device for enzymatic biosensors is fabricated and demonstrated. The design concept of the TIR-based photoluminescent enzymatic biosensor device is explained. An analysis of economical materials with appropriate optical and chemical properties is presented. PMMA and PDMS are found to be appropriate due to their high chemical resistance, low cost, high optical transmittance and low auto-fluorescence. The techniques and procedures used for device fabrication are discussed. The device incorporated a PMMA-based optical waveguide core and PDMS-based fluid cell with simple multi-mode fiber-optics using cost-effective fabrication techniques like molding and surface modification. Several techniques of robustly depositing photoluminescent dyes on PMMA core surface are discussed. A pH-sensitive fluorescent dye, fluoresceinamine, and an O2-sensitive phosphorescent dye, Ru(dpp) both are successfully deposited using Si-adhesive gel-based as well as HydroThane-based deposition methods. Two different types of pH-sensors using two different techniques of depositing fluoresceinamine are demonstrated. Also, the effect of concentration of fluoresceinamine-dye molecules
Michielsen, Kristien; De Meyer, Sara; Ivanova, Olena; Anderson, Ragnar; Decat, Peter; Herbiet, Céline; Kabiru, Caroline W.; Ketting, Evert; Lees, James; Moreau, Caroline; Tolman, Deborah L.; Vega, Bernardo; Verhetsel, Elizabeth; Chandra-Mouli, Venkatraman; Vanwesenbeeck, W.M.A.
2016-01-01
On December 4th 2014, the International Centre for Reproductive Health (ICRH) at Ghent University organized an international conference on adolescent sexual and reproductive health (ASRH) and well-being. This viewpoint highlights two key messages of the conference - 1) ASRH promotion is broadening
Grimes, T. F.; Hagen, A. R.; Archambault, B. C.; Taleyarkhan, R. P.
2018-03-01
This paper describes the development of a SNM detection system for interrogating 1m3 cargos via the combination of a D-D neutron interrogation source (with and without reflectors) and tensioned metastable fluid detectors (TMFDs). TMFDs have been previously shown (Taleyarkhan et al., 2008; Grimes et al., 2015; Grimes and Taleyarkhan, 2016; Archambault et al., 2017; Hagen et al., 2016) to be capable of using Threshold Energy Neutron Analysis (TENA) techniques to reject the ∼2.45 MeV D-D interrogating neutrons while still remaining sensitive to >2.45 MeV neutrons resulting from fission in the target (HEU) material. In order to enhance the performance, a paraffin reflector was included around the accelerator head. This reflector was used to direct neutrons into the package to increase the fission signal, lower the energy of the interrogating neutrons to increase the fission cross-section with HEU, and, also to direct interrogating neutrons away from the detectors in order to enhance the required discrimination between interrogating and fission neutrons. Experiments performed with a 239 Pu-Be neutron source and MnO2 indicated that impressive performance gains could be made by placing a parabolic paraffin moderator between the interrogation source and an air-filled cargo container with HEU placed at the center. However, experiments with other cargo fillers (as specified in the well-known ANSI N42.41-2007 report), and with HEU placed in locations other than the center of the package indicated that other reflector geometries might be superior due to over-"focusing" and the increased solid angle effects due to the accommodation of the moderator geometry. The best performance for the worst case of source location and box fill was obtained by placing the reflector only behind the D-D neutron source rather than in front of it. Finally, it was shown that there could be significant gains in the ability to detect concealed SNM by operating the system in multiple geometric
DEFF Research Database (Denmark)
Thomsen, Dorthe Kirkegaard; Tønnesvang, Jan; Schnieber, Anette
2011-01-01
In three studies it was investigated whether rumination was related to less internalized self-regulation and goals and whether reflection was related to more internalized self-regulation and goals. In all studies students completed questionnaires measuring rumination, reflection, and internalizat...
Interns reflect: the effect of formative assessment with feedback during pre-internship
Directory of Open Access Journals (Sweden)
McKenzie S
2017-01-01
Full Text Available Susan McKenzie,1 Annette Burgess,2 Craig Mellis1 1Central Clinical School, 2Education Office, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia Background: It is widely known that the opportunity for medical students to be observed and to receive feedback on their procedural skills performance is variable in the senior years. To address this problem, we provided our Pre-Intern (PrInt students with “one-to-one” formative feedback on their ability to perform urethral catheterization (U/C and hypothesized that their future practice of U/C as interns would benefit. This study sought to evaluate the performance and practice of interns in U/C 4–5 months after having received feedback on their performance of U/C as PrInt students.Methods: Between 2013 and 2014, two cohorts of interns, (total n=66 who had received recent formative feedback on their U/C performance as PrInt students at Central Clinical School, were invited to complete an anonymous survey. The survey contained nine closed unvalidated questions and one open-ended question, designed to allow interns to report on their current practice of U/C.Results: Forty-one out of 66 interns (62% completed the survey. Thirty-five out of 41 respondents (85% reported that the assessment with feedback during their PrInt term was beneficial to their practice. Thirty of 41 (73% reported being confident to perform U/C independently. Eleven out of 41 respondents (27% reported that they had received additional training at intern orientation. Nine of the 11 interns (82% reported that they had a small, but a significant, increase in confidence to perform U/C when compared with the 30 of the 41 respondents (73% who had not (p=0.03.Conclusion: Our results substantiate our hypothesis that further education by assessment with feedback in U/C during PrInt was of benefit to interns’ performance. Additional educational reinforcement in U/C during intern orientation further improved intern
Smith, Jan
2016-01-01
Research ethics in education is a challenging topic to teach and to learn. As the staff and student body in UK higher education and elsewhere diversifies, the challenges increase as shared reference points diminish. My teaching reflections focus on a key tension explored in this article: how the imperative of internationalising the curriculum…
Leeuwis, C.; Pyburn, R.; Röling, N.G.
2002-01-01
Standing in contrast to technological interventions and economics, ‘social learning’ reflects the idea that the shared learning of interdependent stakeholders is a key mechanism for arriving at more desirable solutions to complex problems in rural environments. Degradation of natural resources,
Directory of Open Access Journals (Sweden)
Michael Crossley
2012-04-01
Full Text Available Recent years have seen a resurgence of interest in comparative and international education, along with a fundamental reconceptualisation of this distinctive multidisciplinary field of study. The nature and significance of these developments are explored with particular reference to their implications for broader research capacity building initiatives worldwide. In doing so, a critique of the international transfer of globally dominant research modalities and strategies is presented--along with arguments for increased attention to context sensitivity in both international development cooperation and educational research in general. Illustrative examples that support these arguments are drawn from the author's own research, from an analysis of emergent educational policy debates in the UK, and from related studies being carried out in Malaysia. In concluding, the strategic role of comparative research traditions and perspectives in a rapidly globalizing world is highlighted, while supporting the promotion of new initiative and research centres for comparative and international education.
DEFF Research Database (Denmark)
Buhmann, Karin
: The paper aims to contribute to our understanding of whether a shift is taking place in societal attitudes towards a perception that corporations have duties based on international law. This is assessed on the basis of EU initiatives on inclusiveness and responsible competitiveness, particularly...... the EU Multistakeholder Forum and the Lisbon Strategy, with a particular focus on goals or views related to the human rights of non-discrimination and rights to work, education and vocational training, and network governance in (soft) law creation. It is found that despite obvious links, international...... law does not serve as a clear source of inclusiveness or responsible competitiveness. It is also found that the initiatives assessed do not indicate a shift at EU institutional level towards a perception that business holds duties under international law. International law seems at the most to be seen...
Interns reflect: the effect of formative assessment with feedback during pre-internship.
McKenzie, Susan; Burgess, Annette; Mellis, Craig
2017-01-01
It is widely known that the opportunity for medical students to be observed and to receive feedback on their procedural skills performance is variable in the senior years. To address this problem, we provided our Pre-Intern (PrInt) students with "one-to-one" formative feedback on their ability to perform urethral catheterization (U/C) and hypothesized that their future practice of U/C as interns would benefit. This study sought to evaluate the performance and practice of interns in U/C 4-5 months after having received feedback on their performance of U/C as PrInt students. Between 2013 and 2014, two cohorts of interns, (total n=66) who had received recent formative feedback on their U/C performance as PrInt students at Central Clinical School, were invited to complete an anonymous survey. The survey contained nine closed unvalidated questions and one open-ended question, designed to allow interns to report on their current practice of U/C. Forty-one out of 66 interns (62%) completed the survey. Thirty-five out of 41 respondents (85%) reported that the assessment with feedback during their PrInt term was beneficial to their practice. Thirty of 41 (73%) reported being confident to perform U/C independently. Eleven out of 41 respondents (27%) reported that they had received additional training at intern orientation. Nine of the 11 interns (82%) reported that they had a small, but a significant, increase in confidence to perform U/C when compared with the 30 of the 41 respondents (73%) who had not ( p =0.03). Our results substantiate our hypothesis that further education by assessment with feedback in U/C during PrInt was of benefit to interns' performance. Additional educational reinforcement in U/C during intern orientation further improved intern confidence. Our results indicate that extra pre- and post-graduation procedural skills training, with feedback, should be universal.
International Nuclear Information System (INIS)
Lorenz, Bernd
2016-01-01
The ICRP international symposium on the radiation protection system provides always extensive information on new developments in radiation protection. The ICRP 2105 discussed the following issues: radiation effects of low dose irradiation, dose coefficients for internal and external exposures, radiation protection in nuclear medicine, application of ICRP recommendations, environmental protection, studies on existing exposure situations, medical radiation protection today, science behind radiation doses, new developments in radiation effects, and ethics in radiation protection.
Troubling Metaphors and International Student Adjustment: Reflections from a Transnational Place
David Starr-Glass
2017-01-01
On many campuses, offices of International Student Affairs address the perceived needs of international students. However, a number of underlying assumptions and persistent metaphors shape these efforts and influence their outcomes. All students are uniquely different and face equally different challenges in adjusting to higher education. Labeling students “international” may make institutional sense, but it can potentially hinder their transition, adjustment, and ultimate success. Applying r...
Burdette, A C
1971-01-01
Analytic Geometry covers several fundamental aspects of analytic geometry needed for advanced subjects, including calculus.This book is composed of 12 chapters that review the principles, concepts, and analytic proofs of geometric theorems, families of lines, the normal equation of the line, and related matters. Other chapters highlight the application of graphing, foci, directrices, eccentricity, and conic-related topics. The remaining chapters deal with the concept polar and rectangular coordinates, surfaces and curves, and planes.This book will prove useful to undergraduate trigonometric st
Berger, Marcel
2010-01-01
Both classical geometry and modern differential geometry have been active subjects of research throughout the 20th century and lie at the heart of many recent advances in mathematics and physics. The underlying motivating concept for the present book is that it offers readers the elements of a modern geometric culture by means of a whole series of visually appealing unsolved (or recently solved) problems that require the creation of concepts and tools of varying abstraction. Starting with such natural, classical objects as lines, planes, circles, spheres, polygons, polyhedra, curves, surfaces,
Robinson, Gilbert de B
2011-01-01
This brief undergraduate-level text by a prominent Cambridge-educated mathematician explores the relationship between algebra and geometry. An elementary course in plane geometry is the sole requirement for Gilbert de B. Robinson's text, which is the result of several years of teaching and learning the most effective methods from discussions with students. Topics include lines and planes, determinants and linear equations, matrices, groups and linear transformations, and vectors and vector spaces. Additional subjects range from conics and quadrics to homogeneous coordinates and projective geom
Connes, Alain
1994-01-01
This English version of the path-breaking French book on this subject gives the definitive treatment of the revolutionary approach to measure theory, geometry, and mathematical physics developed by Alain Connes. Profusely illustrated and invitingly written, this book is ideal for anyone who wants to know what noncommutative geometry is, what it can do, or how it can be used in various areas of mathematics, quantization, and elementary particles and fields.Key Features* First full treatment of the subject and its applications* Written by the pioneer of this field* Broad applications in mathemat
Internal reflection of interstitial atoms from close-packed tungsten faces
International Nuclear Information System (INIS)
Dranova, Zh.I.; Mikhajlovskij, I.M.
1981-01-01
Use of field-ion microscopy methods has shown that changes in microtopography of tungsten specimens irradiated with 2-5 keV helium atoms are mainly related to the liberation of interstitial atoms on the surface. It is established that the atom liberation on the surface is considerably anisotropic: maximum quantity of atoms is observed in the vicinity of faces (100), (111) and (211) along the sections of zone lines (110) oriented along the edge of the first Brillouin zone. The atom liberation on plane sections of the most dense-packed face (110) was not observed as a rule; atomic steps of the face are interstitial atom sinks. It is concluded on the basis of the results obtained that there is the predominant inner reflection of interstitial atoms from the dense-packed faces and a possible contribution of inner reflection to the surface migration processes activated with the ion bombardment as well as material swelling have been analyzed [ru
Indian Academy of Sciences (India)
mathematicians are trained to use very precise language, and so find it hard to simplify and state .... thing. If you take a plane on which there are two such triangles which enjoy the above ... within this geometry to simplify things if needed.
Geometry -----------~--------------RESONANCE
Indian Academy of Sciences (India)
Parallel: A pair of lines in a plane is said to be parallel if they do not meet. Mathematicians were at war ... Subsequently, Poincare, Klein, Beltrami and others refined non-. Euclidean geometry. ... plane divides the plane into two half planes and.
Castillo, Camilo Hernán Manchola; Garrafa, Volnei; Cunha, Thiago; Hellmann, Fernando
2017-07-01
Using the United Nations (UN) and its subordinate body, the World Health Organization (WHO), as a frame of reference, this article explores access to healthcare as a human right in international intergovernmental policies. First, we look at how the theme of health is treated within the UN, focusing on the concept of global health. We then discuss the concept of global health from a human rights perspective and go on to outline the debate surrounding universal coverage versus universal access as a human right, addressing some important ethical questions. Thereafter, we discuss universal coverage versus universal access using the critical and constructivist theories of international relations as a frame of reference. Finally, it is concluded that, faced with the persistence of huge global health inequalities, the WHO began to reshape itself, leaving behind the notion of health as a human right and imposing the challenge of reducing the wide gap that separates international intergovernmental laws from reality.
International Nuclear Information System (INIS)
Arias Canete, A.
1995-01-01
This probably is a suitable moment for work to begin on an international Convention in this area, although it is a difficult task. Generally speaking, the RADWASS (Radioactive Waste Safety Standards) Programme has achieved sufficient consensus, and might serve as an important basis for work in relation to the Convention. The Convention should not go into highly technical details since consensus at this level is more difficult at the present moment, although this will undoubtedly be achieved in the medium term. An important element of the Convention should be the regulation of movements of radioactive wastes at international level. (orig./HP)
Patterson, Timothy
2015-01-01
Common sense thinking on international professional development suggests that the rewards for teachers are automatic. One of the most frequently advertised gains teachers are expected to see from participation includes the likelihood that they will have a transformative experience, whereby aspects of their personal or professional attributes are…
Vos, Lynn
2013-01-01
This article looks at the curriculum redesign of a master's-level program in international marketing from a UK perspective. In order to ensure that the program would be more fit-for-purpose for future managers working under conditions of complexity, uncertainty, and within regimes often very different from the home market, the team began the…
International Nuclear Information System (INIS)
Wigger, Lothar; Buenger, Carsten
2017-01-01
The book on the educational and learning theoretical reflection of nuclear disasters as a consequence of Fukushima includes contributions on the following issues: pedagogical approach: children write on Fukushima, description of the reality as pedagogical challenge; lessons learned on the nuclear technology - perspectives and limits of pedagogical evaluation: moral education - Japanese teaching materials, educational challenges at the universities with respect to nuclear technology and technology impact assessment; education and technology - questions concerning the pedagogical responsibility: considerations on the responsibility of scientists, on the discrepancy between technology and education, disempowerment of the public by structural corruption - nuclear disaster and post-democratic tendencies in Japan.
Wang, Shinn-Fwu
2009-01-01
A small-displacement sensor based on total-internal reflection theory and surface plasmon resonance technology is proposed for use in heterodyne interferometry. A small displacement can be obtained simply by measuring the variation in phase difference between s- and p-polarization states with the small-displacement sensor. The theoretical displacement resolution of the small-displacement sensor can reach 0.45 nm. The sensor has some additional advantages, e.g., a simple optical setup, high resolution, high sensitivity and rapid measurement. Its feasibility is also demonstrated.
International Nuclear Information System (INIS)
Haynie, A.; Min, T.-J.; Luan, L.; Mu, W.; Ketterson, J. B.
2009-01-01
We describe an extension of the total-internal-reflection microscopy technique that permits direct in-plane distance measurements with high accuracy (<10 nm) over a wide range of separations. This high position accuracy arises from the creation of a standing evanescent wave and the ability to sweep the nodal positions (intensity minima of the standing wave) in a controlled manner via both the incident angle and the relative phase of the incoming laser beams. Some control over the vertical resolution is available through the ability to scan the incoming angle and with it the evanescent penetration depth.
Petersen, Peter
2016-01-01
Intended for a one year course, this text serves as a single source, introducing readers to the important techniques and theorems, while also containing enough background on advanced topics to appeal to those students wishing to specialize in Riemannian geometry. This is one of the few Works to combine both the geometric parts of Riemannian geometry and the analytic aspects of the theory. The book will appeal to a readership that have a basic knowledge of standard manifold theory, including tensors, forms, and Lie groups. Important revisions to the third edition include: a substantial addition of unique and enriching exercises scattered throughout the text; inclusion of an increased number of coordinate calculations of connection and curvature; addition of general formulas for curvature on Lie Groups and submersions; integration of variational calculus into the text allowing for an early treatment of the Sphere theorem using a proof by Berger; incorporation of several recent results about manifolds with posit...
International Nuclear Information System (INIS)
Strominger, A.
1990-01-01
A special manifold is an allowed target manifold for the vector multiplets of D=4, N=2 supergravity. These manifolds are of interest for string theory because the moduli spaces of Calabi-Yau threefolds and c=9, (2,2) conformal field theories are special. Previous work has given a local, coordinate-dependent characterization of special geometry. A global description of special geometries is given herein, and their properties are studied. A special manifold M of complex dimension n is characterized by the existence of a holomorphic Sp(2n+2,R)xGL(1,C) vector bundle over M with a nowhere-vanishing holomorphic section Ω. The Kaehler potential on M is the logarithm of the Sp(2n+2,R) invariant norm of Ω. (orig.)
Reflections of a TMS International Scholar: Sharing Research across Cultures and Continents
Energy Technology Data Exchange (ETDEWEB)
Unocic, Kinga A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2017-07-19
Here, I was honored to be selected as the 2017 Japan Institute of Metals (JIM)/TMS Young Leaders International Scholar, an opportunity made possible by the TMS Foundation. One of the benefits of receiving this award for me was traveling to Japan to visit the National Institute for Materials Science (NIMS), and attending the 2017 JIM Annual Spring Meeting, held at the Tokyo Metropolitan University.
"They Will Come to Understand": Supervisor Reflections on International Medical Electives.
Roebbelen, Erica; Dorman, Katie; Hunter, Andrea; Kraeker, Christian; O'Shea, Tim; Bozinoff, Nikki
2018-03-22
Phenomenon: Increasing numbers of medical students from high-income countries are undertaking international medical electives (IMEs) during their training. Much has been written about the benefits of these experiences for the student, and concerns have been raised regarding the burden of IMEs on host communities. The voices of physicians from low- and middle-income countries who supervise IMEs have not been explored in depth. The current study sought to investigate host-physician perspectives on IMEs. Host supervisors were recruited by convenience sampling through students travelling abroad for IMEs during the summer of 2012. From 2012 through 2014, 11 semistructured interviews were conducted by telephone with host supervisors from Nepal, Uganda, Ghana, Guyana, and Kenya. Participants were invited to describe their motivations for hosting IMEs and their experiences of the benefits and harms of IMEs. Interviews were transcribed verbatim and checked for accuracy. An initial coding framework was developed and underwent multiple revisions, after which analytic categories were derived using conventional qualitative content analysis. For host supervisors, visits from international medical students provided a window into the resource-rich medical practice of high-income countries, and supervisors positioned themselves, their education, and clinical expertise against perceived standards of the international students' context. Hosting IMEs also contributed to supervisors' identities as educators connected to a global community. Supervisors described the challenge of helping students navigate their distress when confronting global health inequity. Finally, the desire for increasingly reciprocal relationships was expressed as a hope for the future. Insights: IMEs can be formative for host supervisors' identities and are used to benchmark host institutions compared with international medical standards. Reciprocity was articulated as essential for IMEs moving forward.
González-Escobar, Mario; Suárez-Vidal, Francisco; Hernández-Pérez, José Antonio; Martín-Barajas, Arturo
2010-12-01
This study examines the structural characteristics of the northern Gulf of California by processing and interpreting ca. 415 km of two-dimensional multi-channel seismic reflection lines (data property of Petróleos Mexicanos PEMEX) collected in the vicinity of the border between the Wagner and Consag basins. The two basins appear to be a link between the Delfín Superior Basin to the south, and the Cerro Prieto Basin to the north in the Mexicali-Imperial Valley along the Pacific-North America plate boundary. The seismic data are consistent with existing knowledge of four main structures (master faults) in the region, i.e., the Percebo, Santa María, Consag Sur, and Wagner Sur faults. The Wagner and Consag basins are delimited to the east by the Wagner Sur Fault, and to the west by the Consag Sur Fault. The Percebo Fault borders the western margin of the modern Wagner Basin depocenter, and is oriented N10°W, dipping (on average) ˜40° to the northeast. The trace of the Santa María Fault located in the Wagner Basin strikes N19°W, dipping ˜40° to the west. The Consag Sur Fault is oriented N14°W, and dips ˜42° to the east over a distance of 21 km. To the east of the study area, the Wagner Sur Fault almost parallels the Consag Sur Fault over a distance of ˜86 km, and is oriented N10°W with an average dip of 59° to the east. Moreover, the data provide new evidence that the Wagner Fault is discontinuous between the two basins, and that its structure is more complex than previously reported. A structural high separates the northern Consag Basin from the southern Wagner Basin, comprising several secondary faults oriented NE oblique to the main faults of N-S direction. These could represent a zone of accommodation, or transfer zone, where extension could be transferred from the Wagner to the Consag Basin, or vice versa. This area shows no acoustic basement and/or intrusive body, which is consistent with existing gravimetric and magnetic data for the region.
General Geometry and Geometry of Electromagnetism
Shahverdiyev, Shervgi S.
2002-01-01
It is shown that Electromagnetism creates geometry different from Riemannian geometry. General geometry including Riemannian geometry as a special case is constructed. It is proven that the most simplest special case of General Geometry is geometry underlying Electromagnetism. Action for electromagnetic field and Maxwell equations are derived from curvature function of geometry underlying Electromagnetism. And it is shown that equation of motion for a particle interacting with electromagnetic...
Interns reflect: the effect of formative assessment with feedback during pre-internship
McKenzie, Susan; Burgess, Annette; Mellis, Craig
2017-01-01
Susan McKenzie,1 Annette Burgess,2 Craig Mellis1 1Central Clinical School, 2Education Office, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia Background: It is widely known that the opportunity for medical students to be observed and to receive feedback on their procedural skills performance is variable in the senior years. To address this problem, we provided our Pre-Intern (PrInt) students with “one-to-one” formative feedback on their ability to p...
Critical Reflection on the Reception of Vygotsky’s Theory in the International Academic Communities
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Dafermos M.,
2016-12-01
Full Text Available This paper is an attempt to analyze various types of the reception of Vygotsky’s theory in the international academic communities. The paper develops a critical analysis of three widespread theoretical frameworks of interpretation of Vygotsky’s theory: cognitivism, culturalism, cultural-historical activity theory. It is argues that fragmented readings of particular ideas of Vygotsky, without enough understanding of the theoretical programme in which these ideas have been included dominates in North-Atlantic research. The paper proposes the reconstruction of the theoretical programme of cultural-historical psychology in the social and scientific context of its formation.
Ensink, Karin; Bégin, Michaël; Normandin, Lina; Fonagy, Peter
2017-11-01
The objective was to examine pathways from child sexual abuse (CSA) and maternal mentalizing to child internalizing and externalizing difficulties and to test a model of MRF as a moderator of the relationships between CSA and child difficulties. The sample was comprised of 154 mothers and children aged 2-12 where 64 children had experienced CSA. To assess parental mentalizing the Parental Development Interview was rated with the Parental Reflective Functioning Scale. Child internalizing and externalizing difficulties were assessed with the Child Behavior Checklist (CBCL). Results indicate that there were significant inverse relationships between maternal mentalizing and child internalizing and externalizing difficulties. When maternal mentalizing was considered together with CSA, only maternal mentalizing was a significant predictor of child difficulties. Furthermore, maternal mentalizing moderated the relationship between CSA and child internalizing difficulties. These findings provide evidence of the importance of the parents' mentalizing stance for psychiatric symptoms of children aged 2-12, as well as children's recovery from CSA. The clinical implications of the findings are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.
Finsler geometry, relativity and gauge theories
International Nuclear Information System (INIS)
Asanov, G.S.
1985-01-01
This book provides a self-contained account of the Finslerian techniques which aim to synthesize the ideas of Finslerian metrical generalization of Riemannian geometry to merge with the primary physical concepts of general relativity and gauge field theories. The geometrization of internal symmetries in terms of Finslerian geometry, as well as the formulation of Finslerian generalization of gravitational field equations and equations of motion of matter, are two key points used to expound the techniques. The Clebsch representation of the canonical momentum field is used to formulate the Hamilton-Jacobi theory for homogeneous Lagrangians of classical mechanics. As an auxillary mathematical apparatus, the author uses invariance identities which systematically reflect the covariant properties of geometrical objects. The results of recent studies of special Finsler spaces are also applied. The book adds substantially to the mathematical monographs by Rund (1959) and Rund and Bear (1972), all basic results of the latter being reflected. It is the author's hope that thorough exploration of the materrial presented will tempt the reader to revise the habitual physical concepts supported conventionally by Riemannian geometry. (Auth.)
Directory of Open Access Journals (Sweden)
Ricardo Lopes Cardoso
2010-01-01
Full Text Available The main purpose of this study is to understand what the competences of the Management accountant are, compare to international studies and assess the existence of competences to be prioritized. This questioning has as motivation the placements of Hardern (1995, Morgan (1997, IMA (1996 e 1999 and IFAC (2003. The theoretical basis about competences is related to McClelland study (1973, 1998, Boyatzis (1982 and Spencer and Spencer (1993. This research is based on the study of 18 competences about knowledge, skills and attitudes obtained in accountant literature and that have been submitted to 200 Management accountants. Data collection instrument presented a 0.884 Cronbach Alpha. From a factorial analysis and after Kruskal-Wallis test 12 competences were obtained as the most relevant segregated in 3 factors, in comparison to international studies of nine common competences 4 were not considered relevant in statistical tests and only one must be prioritized. Results demonstrate differences between competences required from Brazilian Management accountants and from other countries, being that their reasons is an open-ended question up to the moment.
Caxaj, C Susana
2015-01-01
Storytelling, in its various forms, has often been described as a practice with great emancipatory potential. In turn, Indigenous knowledge shows great promise in guiding a participatory action research (PAR) methodology. Yet these two approaches are rarely discussed in relation to one another, nor, has much been written in terms of how these two approaches may work synergistically toward a decolonizing research approach. In this article, I report on a community-driven knowledge translation activity, the Peoples' International Health Tribunal, as an exemplar of how narrative and PAR approaches, guided by local Indigenous knowledge, have great potential to build methodologically and ethically robust research processes. Implications for building globally relevant research alliances and scholarship are further discussed, particularly in relation to working with Indigenous communities.
Ciarlet, Philippe G
2007-01-01
This book gives the basic notions of differential geometry, such as the metric tensor, the Riemann curvature tensor, the fundamental forms of a surface, covariant derivatives, and the fundamental theorem of surface theory in a selfcontained and accessible manner. Although the field is often considered a classical one, it has recently been rejuvenated, thanks to the manifold applications where it plays an essential role. The book presents some important applications to shells, such as the theory of linearly and nonlinearly elastic shells, the implementation of numerical methods for shells, and
Grenoble, Zlata; Baldelli, Steven
2013-08-29
The adsorption of the cationic surfactant benzyldimethylhexadecylammonium (BDMHA(+)) chloride was studied at an octadecyltrichlorosilane (OTS)-monolayer-modified silica-water interface by Raman spectroscopy in total internal reflection (TIR) geometry. The present study demonstrates the capabilities of this spectroscopic technique to evaluate thermodynamic and kinetic BDMHA(+)Cl(-) adsorption properties at the hydrophobic silica surface. The surface coverage of BDMHA(+) decreased by 50% at the hydrophobic OTS-silica surface relative to the surface coverage on bare silica; the dominating driving mechanisms for surfactant adsorption were identified as hydrophobic effects and head group charge screening by the electrolyte counterions. Addition of magnesium metal salt (MgCl2) to the aqueous solution (∼ neutral pH) lowered the surface coverage and moderately increased the Langmuir adsorption constants relative to those of the pure surfactant. These trends were previously observed at the hydrophilic, negatively charged silica surface but with a smaller change in the Gibbs free energy of adsorption at the hydrophobic silica surface. The hydrophobic OTS-silica surface properties resulted in shorter times for the surfactant to reach steady-state adsorption conditions compared to the slow adsorption kinetics previously seen with the surfactant at the hydrophilic surface. Adsorption isotherms, based on Raman signal intensities from spectral analysis, were developed according to the Langmuir adsorption model for the pure surfactant at the OTS-silica-water interface; the modified Langmuir model was applied to the surfactant adsorption in the presence of 5, 10, 50, and 100 mM magnesium chloride. Spectral analysis of the Raman scattering intensities and geometric considerations suggests a hemimicelle-type surface aggregate as the most likely surfactant structure at the OTS-silica surface. The different kinetics observed at the hydrophilic versus the hydrophobic silica surface
Martinez, Nicole
The first study in Part 1 examines the effects of lake tropic structure on the uptake of iodine-131 (131I) in rainbow trout (Oncorhynchus mykiss) and considers a simple computational model for the estimation of resulting radiation dose. Iodine-131 is a major component of the atmospheric releases following reactor accidents, and the passage of 131I through food chains from grass to human thyroids has been extensively studied. By comparison, the fate and effects of 131I deposition onto lakes and other aquatic systems has been less studied. In this study we reanalyze 1960s data from experimental releases of 131I into two small lakes and compare the effects of differences in lake trophic structures on 131I accumulation in fish. The largest concentrations in the thyroids of trout may occur from 8 to 32 days post initial release. DCFs for trout for whole body as well as thyroid were computed using Monte Carlo modeling with an anatomically-appropriate model of trout thyroid structure. Activity concentration data was used in conjunction with the calculated DCFs to estimate dose rates and ultimately determine cumulative radiation dose (Gy) to the thyroids after 32 days. The estimated cumulative thyroid doses at 32 days post-release ranged from 6 mGy to 18 mGy per 1 Bq mL-1 of initial 131I in the water, depending upon fish size. The subsequent studies in Part 1 seek to develop and compare different, increasingly detailed anatomical phantoms for O. mykiss for the purpose of estimating organ radiation dose and dose rates from 131I uptake and from molybdenum-99 (99Mo) uptake. Model comparison and refinement is important to the process of determining both dose rates and dose effects, and we develop and compare three models for O. mykiss: a simplistic geometry considering a single organ, a more specific geometry employing anatomically relevant organ size and location, and voxel reconstruction of internal anatomy obtained from CT imaging (referred to as CSUTROUT). Dose Conversion
Struckmeier, Willi; Howard, Ken; Chilton, John
2016-08-01
The 60th anniversary of the founding of the International Association of Hydrogeologists (IAH) is an important milestone that allows pause for reflection on how the association has evolved over the years and the contributions it has made to groundwater science and water management. IAH was founded in 1956 at the 20th International Geological Congress and developed rapidly during the 1980s and 1990s in response to a growing global interest in groundwater mapping and in sound approaches to resource protection and sustainable aquifer management. Incorporated in 2000, IAH has now secured its position as the world's leading international association specialising in groundwater with over 4,100 members in 131 countries. Much credit for this success must go to members, past and present, whose individual efforts and collaboration with sister institutions are documented here. These members have shaped the association's goals and contributed selflessly to its scientific programmes, publications and educational and charitable activities. Looking ahead to the next 60 years, it is essential that IAH does not rest on past achievements but listens and adjusts to the needs of members while continuing to pursue its mission of furthering the understanding, wise use and protection of groundwater resources throughout the world.
Córdova Pozo, Kathya; Chandra-Mouli, Venkatraman; Decat, Peter; Nelson, Erica; De Meyer, Sara; Jaruseviciene, Lina; Vega, Bernardo; Segura, Zoyla; Auquilla, Nancy; Hagens, Arnold; Van Braeckel, Dirk; Michielsen, Kristien
2015-01-24
In February 2014, an international congress on Promoting Adolescent Sexual and Reproductive Health (ASRH) took place in Cuenca, Ecuador. Its objective was to share evidence on effective ASRH intervention projects and programs in Latin America, and to link this evidence to ASRH policy and program development. Over 800 people participated in the three-day event and sixty-six presentations were presented.This paper summarizes the key points of the Congress and of the Community Embedded Reproductive Health Care for Adolescents (CERCA) project. It aims at guiding future ASRH research and policy in Latin America. 1. Context matters. Individual behaviors are strongly influenced by the social context in which they occur, through determinants at the individual, relational, family, community and societal levels. Gender norms/attitudes and ease of communication are two key determinants. 2. Innovative action. There is limited and patchy evidence of effective approaches to reach adolescents with the health interventions they need at scale. Yet, there exist several promising and innovative examples of providing comprehensive sexuality education through conventional approaches and using new media, improving access to health services, and reaching adolescents as well as families and community members using community-based interventions were presented at the Congress. 3. Better measurement. Evaluation designs and indicators chosen to measure the effect and impact of interventions are not always sensitive to subtle and incremental changes. This can create a gap between measured effectiveness and the impact perceived by the targeted populations. Thus, one conclusion is that we need more evidence to better determine the factors impeding progress in ASRH in Latin American, to innovate and respond flexibly to changing social dynamics and cultural practices, and to better measure the impact of existing intervention strategies. Yet, this Congress offered a starting point from which to
Johnson, Heath E; Haugh, Jason M
2013-12-02
This unit focuses on the use of total internal reflection fluorescence (TIRF) microscopy and image analysis methods to study the dynamics of signal transduction mediated by class I phosphoinositide 3-kinases (PI3Ks) in mammalian cells. The first four protocols cover live-cell imaging experiments, image acquisition parameters, and basic image processing and segmentation. These methods are generally applicable to live-cell TIRF experiments. The remaining protocols outline more advanced image analysis methods, which were developed in our laboratory for the purpose of characterizing the spatiotemporal dynamics of PI3K signaling. These methods may be extended to analyze other cellular processes monitored using fluorescent biosensors. Copyright © 2013 John Wiley & Sons, Inc.
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Ryan, M.A.; Fitzgerald, E.C.; Spitler, M.T. (Polaroid Corp., Cambridge, MA (USA))
1989-08-10
It is shown that the photoelectrochemical data on eosin Y sensitized TiO{sub 2} single-crystal electrodes cannot be interpreted unambiguously without concomitant data from flash photolysis measurements on this system. By use of a combination of internal reflection spectroscopy and laser flash photolysis, electron exchange with TiO{sub 2} was observed for the excited singlet state, the triplet state, and the cation radical of the dye. With a temporal resolution of 100 ns, the kinetics of the charge transfer are compared with those of the dye in solution and used to interpret the photoelectrochemistry of the dye at the electrode. Spectroscopic evidence revealed photocurrent production by the triplet state and a reduction of the eosin cation radical by electrons from the TiO{sub 2} conduction band and by hydroquinone.
International Nuclear Information System (INIS)
Wang Lei; Xu Guang; Shi Zhikun; Jiang Wei; Jin Wenrui
2007-01-01
We developed a sensitive single-molecule imaging method for quantification of protein by total internal reflection fluorescence microscopy with adsorption equilibrium. In this method, the adsorption equilibrium of protein was achieved between solution and glass substrate. Then, fluorescence images of protein molecules in a evanescent wave field were taken by a highly sensitive electron multiplying charge coupled device. Finally, the number of fluorescent spots corresponding to the protein molecules in the images was counted. Alexa Fluor 488-labeled goat anti-rat IgG(H + L) was chosen as the model protein. The spot number showed an excellent linear relationship with protein concentration. The concentration linear range was 5.4 x 10 -11 to 8.1 x 10 -10 mol L -1
Directory of Open Access Journals (Sweden)
Yoshihiro Kawano
Full Text Available We present a new method for whole slide darkfield imaging. Whole Slide Imaging (WSI, also sometimes called virtual slide or virtual microscopy technology, produces images that simultaneously provide high resolution and a wide field of observation that can encompass the entire section, extending far beyond any single field of view. For example, a brain slice can be imaged so that both overall morphology and individual neuronal detail can be seen. We extended the capabilities of traditional whole slide systems and developed a prototype system for darkfield internal reflection illumination (DIRI. Our darkfield system uses an ultra-thin light-emitting diode (LED light source to illuminate slide specimens from the edge of the slide. We used a new type of side illumination, a variation on the internal reflection method, to illuminate the specimen and create a darkfield image. This system has four main advantages over traditional darkfield: (1 no oil condenser is required for high resolution imaging (2 there is less scatter from dust and dirt on the slide specimen (3 there is less halo, providing a more natural darkfield contrast image, and (4 the motorized system produces darkfield, brightfield and fluorescence images. The WSI method sometimes allows us to image using fewer stains. For instance, diaminobenzidine (DAB and fluorescent staining are helpful tools for observing protein localization and volume in tissues. However, these methods usually require counter-staining in order to visualize tissue structure, limiting the accuracy of localization of labeled cells within the complex multiple regions of typical neurohistological preparations. Darkfield imaging works on the basis of light scattering from refractive index mismatches in the sample. It is a label-free method of producing contrast in a sample. We propose that adapting darkfield imaging to WSI is very useful, particularly when researchers require additional structural information without the
Schmitz, R.; Yordanov, S.; Butt, H. J.; Koynov, K.; Dünweg, B.
2011-12-01
Total internal reflection fluorescence cross-correlation spectroscopy (TIR-FCCS) has recently [S. Yordanov , Optics ExpressOPEXFF1094-408710.1364/OE.17.021149 17, 21149 (2009)] been established as an experimental method to probe hydrodynamic flows near surfaces, on length scales of tens of nanometers. Its main advantage is that fluorescence occurs only for tracer particles close to the surface, thus resulting in high sensitivity. However, the measured correlation functions provide only rather indirect information about the flow parameters of interest, such as the shear rate and the slip length. In the present paper, we show how to combine detailed and fairly realistic theoretical modeling of the phenomena by Brownian dynamics simulations with accurate measurements of the correlation functions, in order to establish a quantitative method to retrieve the flow properties from the experiments. First, Brownian dynamics is used to sample highly accurate correlation functions for a fixed set of model parameters. Second, these parameters are varied systematically by means of an importance-sampling Monte Carlo procedure in order to fit the experiments. This provides the optimum parameter values together with their statistical error bars. The approach is well suited for massively parallel computers, which allows us to do the data analysis within moderate computing times. The method is applied to flow near a hydrophilic surface, where the slip length is observed to be smaller than 10nm, and, within the limitations of the experiments and the model, indistinguishable from zero.
Teng, Tun-Chien; Lai, Wei-Che
2014-12-15
This study proposed a planar solar concentrator featuring alignment-free total-internal-reflection (TIR) collectors and an innovative compound tracker. The compound tracker, combining a mechanical single-axis tracker and scrollable prism sheets, can achieve a performance on a par with dual-axis tracking while reducing the cost of the tracking system and increasing its robustness. The alignment-free TIR collectors are assembled on the waveguide without requiring alignment, so the planar concentrator is relatively easily manufactured and markedly increases the feasibility for use in large concentrators. Further, the identical TIR collector is applicable to various-sized waveguide slab without requiring modification, which facilitates flexibility regarding the size of the waveguide slab. In the simulation model, the thickness of the slab was 2 mm, and its maximal length reached 6 m. With an average angular tolerance of ±0.6°, and after considering both the Fresnel loss and the angular spread of the sun, the simulation indicates that the waveguide concentrator of a 1000-mm length provides the optical efficiencies of 62-77% at the irradiance concentrations of 387-688, and the one of a 2000-mm length provides the optical efficiencies of 52-64.5% at the irradiance concentrations of 645-1148. Alternatively, if a 100-mm horizontally staggered waveguide slab is collocated with the alignment-free TIR collectors, the optical efficiency would be greatly improved up to 91.5% at an irradiance concentration of 1098 (C(geo) = 1200X).
Ling, Chen; Sommer, André J
2015-06-01
Until recently, the analysis of polymer laminates using infrared microspectroscopy involved the painstaking separation of individual layers by dissection or by obtaining micrometer thin cross-sections. The latter usually requires the expertise of an individual trained in microtomy and even then, the very structure of the laminate could affect the outcome of the spectral results. The recent development of attenuated total internal reflection (ATR) infrared microspectroscopy imaging has provided a new avenue for the analysis of these multilayer structures. This report compares ATR infrared microspectroscopy imaging with conventional transmission infrared microspectroscopy imaging. The results demonstrate that the ATR method offers improved spatial resolution, eliminates a variety of competing optical processes, and requires minimal sample preparation relative to transmission measurements. These advantages were illustrated using a polymer laminate consisting of 11 different layers whose thickness ranged in size from 4-20 μm. The spatial resolution achieved by using an ATR-FTIR (Fourier transform infrared spectroscopy) imaging technique was diffraction limited. Contrast in the ATR images was enhanced by principal component analysis.
KEMAJUAN BELAJAR SISWA PADA GEOMETRI TRANSFORMASI MENGGUNAKAN AKTIVITAS REFLEKSI GEOMETRI
Directory of Open Access Journals (Sweden)
Irkham Ulil Albab
2014-10-01
Full Text Available Abstrak: Penelitian ini bertujuan untuk mendeskripsikan kemajuan belajar siswa pada materi geometri transformasi yang didukung dengan serangkaian aktivitas belajar berdasarkan Pendidikan Matematika Realistik Indonesia. Penelitian didesain melalui tiga tahap, yaitu tahapan perancangan desain awal, pengujian desain melalui pembelajaran awal dan pembelajaran eksperimental, dan tahap analisis retrospektif. Dalam penelitian ini, Hypothetical Learning Trajectory, HLT (HLT berperan penting sebagai desain pembelajaran sekaligus instrumen penelitian. HLT diujikan terhadap 26 siswa kelas VII. Data dikumpulkan dengan teknik wawancara, pengamatan, dan catatan lapangan. Hasil penelitian menunjukkan bahwa desain pembelajaran ini mampu menstimulasi siswa untuk memberikan karakteristik refleksi dan transformasi geometri lainnya secara informal, mengklasifikasikannya dalam transformasi isometri pada level kedua, dan menemukan garis bantuan refleksi pada level yang lebih formal. Selain itu, garis bantuan refleksi digunakan oleh siswa untuk menggambar bayangan refleksi dan pola pencerminan serta memahami bentuk rotasi dan translasi sebagai kombinasi refleksi adalah level tertinggi. Keyword: transformasi geometri, kombinasi refleksi, rotasi, translasi, design research, HLT STUDENTS’ LEARNING PROGRESS ON TRANSFORMATION GEOMETRY USING THE GEOMETRY REFLECTION ACTIVITIES Abstract: This study was aimed at describing the students’ learning progress on transformation geometry supported by a set of learning activities based on Indonesian Realistic Mathematics Education. The study was designed into three stages, that is, the preliminary design stage, the design testing through initial instruction and experiment, and the restrospective analysis stage. In this study, Hypothetical Learning Trajectory (HLT played an important role as an instructional design and a research instrument. HLT was tested to 26 seventh grade students. The data were collected through interviews
Silva, Alessandro
1993-01-01
The papers in this wide-ranging collection report on the results of investigations from a number of linked disciplines, including complex algebraic geometry, complex analytic geometry of manifolds and spaces, and complex differential geometry.
Eisenhart, Luther Pfahler
2005-01-01
This concise text by a prominent mathematician deals chiefly with manifolds dominated by the geometry of paths. Topics include asymmetric and symmetric connections, the projective geometry of paths, and the geometry of sub-spaces. 1927 edition.
International Nuclear Information System (INIS)
Gurevich, L.Eh.; Gliner, Eh.B.
1978-01-01
Problems of investigating the Universe space-time geometry are described on a popular level. Immediate space-time geometries, corresponding to three cosmologic models are considered. Space-time geometry of a closed model is the spherical Riemann geonetry, of an open model - is the Lobachevskij geometry; and of a plane model - is the Euclidean geometry. The Universe real geometry in the contemporary epoch of development is based on the data testifying to the fact that the Universe is infinitely expanding
International Nuclear Information System (INIS)
Sabry, Mohamed
2016-01-01
Low-concentration Façade-integrated Photovoltaic system in the form of TIR (total internal reflection) prismatic segmented façade could play an effective role in reducing the direct component of solar radiation transmitting through buildings, hence reducing both cooling and artificial lighting load on such buildings. A prismatic segmented façade is capable of allowing diffused skylight to transmit through it to the building interior, while preventing most of the direct solar radiation and converting it into clean energy by means of the integrated PV (photovoltaics) cells. A range of prismatic TIR segmented façades with different head angles has been designed based on the geographical latitude of the chosen location. Each façade configuration is simulated by ray-tracing technique and its performance is investigated against realistic direct solar radiation data in two clear sky days representing summer and winter of the targeted location. Ray tracing simulations revealed that all of the selected configurations could collect most of the direct solar radiation in summer. In contrary, larger head angle of the segmented façade could collect wider intervals around the noon time till reaching a head angle of 23° at which most of the incident direct solar radiation could be collected. - Highlights: • 5 different head angles of prismatic segmented PV-integrated Façade are ray-traced. • Transmitted and PV-collected solar radiation percentages are determined. • DNI daily profiles with associated solar altitudes and azimuth data are simulated. • Expected transmitted and PV collected solar radiation are calculated for the proposed segments.
Fierke, Kerry K.; Lepp, Gardner A.; Bastianelli, Karen; Vogelsang, Lisa; Tornabene, Ladona
2016-01-01
The article describes a student-centered approach to generating meaningful learning outcomes in a short-term study abroad program. A practice named Intention/Reflection (I/R) was used to help students to identify, articulate, and reflect upon learning objectives that were personally meaningful, within the broader framework of the intended outcomes…
Ryngaert, C.M.J.
2016-01-01
The Netherlands is home to a substantial number of international organizations, which on the basis of international agreements are entitled to immunity from jurisdiction and enforcement before Dutch courts. This immunity grant has not stopped claimants from suing international organizations in The
Euclidean geometry and its subgeometries
Specht, Edward John; Calkins, Keith G; Rhoads, Donald H
2015-01-01
In this monograph, the authors present a modern development of Euclidean geometry from independent axioms, using up-to-date language and providing detailed proofs. The axioms for incidence, betweenness, and plane separation are close to those of Hilbert. This is the only axiomatic treatment of Euclidean geometry that uses axioms not involving metric notions and that explores congruence and isometries by means of reflection mappings. The authors present thirteen axioms in sequence, proving as many theorems as possible at each stage and, in the process, building up subgeometries, most notably the Pasch and neutral geometries. Standard topics such as the congruence theorems for triangles, embedding the real numbers in a line, and coordinatization of the plane are included, as well as theorems of Pythagoras, Desargues, Pappas, Menelaus, and Ceva. The final chapter covers consistency and independence of axioms, as well as independence of definition properties. There are over 300 exercises; solutions to many of the...
Voloshinov, Vitaly; Polikarpova, Nataliya; Ivanova, Polina; Khorkin, Vladimir
2018-04-01
Peculiar cases of acoustic wave propagation and reflection may be observed in strongly anisotropic acousto-optical crystals. A tellurium dioxide crystal serves as a prime example of such media, since it possesses record indexes of acoustic anisotropy. We studied one of the unusual scenarios of acoustic incidence and reflection from a free crystal-vacuum boundary in paratellurite. The directions of the acoustic waves in the (001) plane of the crystal were determined, and their basic characteristics were calculated. The carried-out acousto-optic experiment at the wavelength of light 532 nm and the acoustic frequency 73 MHz confirmed the theoretical predictions. The effects examined in the paper include the acoustic wave propagation with the record walkoff angle 74°. We also observed the incidence of the wave on the boundary at the angle exceeding 90°. Finally, we registered the close-to-back reflection of acoustic energy following the incidence. One of the stunning aspects is the distribution of energy between the incident and the back-reflected wave. The unusual features of the acoustic wave reflections pointed out in the paper are valuable for their possible applications in acousto-optic devices.
Directory of Open Access Journals (Sweden)
Buddhini Gayathri Jayatilleke
2017-03-01
Full Text Available This research paper discusses the accomplishments, issues, and challenges experienced by Open University of Sri Lanka (OUSL academics when offering the first cross-border professional development online course to train online tutors and mentors. The course was delivered exclusively online and facilitated by OUSL academics and e-mentors from the USA. The course was comprised of 30 participants: 9 from Pakistan, 10 from Mauritius and 11 from Sri Lanka. This qualitative study is based on reflections of both faculty and participants. Data were collected using reflections and informal anecdotal records of the three OUSL academics and self-reflection instruments (pre, mid and final administered to participants, and reflective journal entries made by participants. Participants’ views were triangulated with the reflections of the OUSL academics to validate the results. While there were many accomplishments in the design and delivery of the course, the findings revealed that there were many challenges in implementing the course: pedagogical, organizational and technological aspects in particular. The paper provides recommendations to address such challenges when offering cross-border online courses in the future.
Greene, Catie A.
2016-01-01
The purpose of this research was to investigate the sociocultural model of eating disorder development among male and female college student-athletes as moderated by students' level of Reflective Judgment, a stage theory of adult epistemology marked by increasing cognitive complexity. A review of literature on the established relationships between…
Meyer, Walter J
2006-01-01
Meyer''s Geometry and Its Applications, Second Edition, combines traditional geometry with current ideas to present a modern approach that is grounded in real-world applications. It balances the deductive approach with discovery learning, and introduces axiomatic, Euclidean geometry, non-Euclidean geometry, and transformational geometry. The text integrates applications and examples throughout and includes historical notes in many chapters. The Second Edition of Geometry and Its Applications is a significant text for any college or university that focuses on geometry''s usefulness in other disciplines. It is especially appropriate for engineering and science majors, as well as future mathematics teachers.* Realistic applications integrated throughout the text, including (but not limited to): - Symmetries of artistic patterns- Physics- Robotics- Computer vision- Computer graphics- Stability of architectural structures- Molecular biology- Medicine- Pattern recognition* Historical notes included in many chapters...
Indian Academy of Sciences (India)
algebraic geometry but also in related fields like number theory. ... every vector bundle on the affine space is trivial. (equivalently ... les on a compact Riemann surface to unitary rep- ... tial geometry and topology and was generalised in.
International Nuclear Information System (INIS)
Sloane, Peter
2007-01-01
We adapt the spinorial geometry method introduced in [J. Gillard, U. Gran and G. Papadopoulos, 'The spinorial geometry of supersymmetric backgrounds,' Class. Quant. Grav. 22 (2005) 1033 [ (arXiv:hep-th/0410155)
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Sloane, Peter [Department of Mathematics, King' s College, University of London, Strand, London WC2R 2LS (United Kingdom)
2007-09-15
We adapt the spinorial geometry method introduced in [J. Gillard, U. Gran and G. Papadopoulos, 'The spinorial geometry of supersymmetric backgrounds,' Class. Quant. Grav. 22 (2005) 1033 [ (arXiv:hep-th/0410155)
International Nuclear Information System (INIS)
Cavalanti, C. de A.
1992-01-01
The growing importance of nuclear energy (on the threshold of the twenty-first century) and of its ethical uses is considered, including major political events in recent years, their social and economic consequences in the world scene. International Nuclear Law is seen as the most adequate instrument to promote the ethical uses of nuclear energy on a worldwide basis, so that mankind can benefit safely and properly and improving their living conditions in general. Problems associated with access to nuclear technology, plants, equipments and materials are addressed. Basic principles of international agreements ruling nuclear trade, ethical aspects are also covered. The different markets involved in international nuclear trade and their specific requirements are described. Certain international treaties on the peaceful uses of nuclear energy are discussed such as the Non-Proliferation Treaty and the Tlatelolco Treaty as are international conventions on matters related to the use of nuclear energy, such as the environment and protection of personnel. The author concludes by debating whether ethical uses of nuclear energy are a possible reality or merely utopia. Prospects on the future of international nuclear trade are considered. (author)
Reflecting reflection in supervision
DEFF Research Database (Denmark)
Lystbæk, Christian Tang
associated with reflection and an exploration of alternative conceptions that view reflection within the context of settings which have a more group- and team-based orientation. Drawing on an action research project on health care supervision, the paper questions whether we should reject earlier views...... of reflection, rehabilitate them in order to capture broader connotations or move to new ways of regarding reflection that are more in keeping with not only reflective but also emotive, normative and formative views on supervision. The paper presents a critical perspective on supervision that challenge...... the current reflective paradigm I supervision and relate this to emotive, normative and formative views supervision. The paper is relevant for Nordic educational research into the supervision and guidance...
Geometry essentials for dummies
Ryan, Mark
2011-01-01
Just the critical concepts you need to score high in geometry This practical, friendly guide focuses on critical concepts taught in a typical geometry course, from the properties of triangles, parallelograms, circles, and cylinders, to the skills and strategies you need to write geometry proofs. Geometry Essentials For Dummies is perfect for cramming or doing homework, or as a reference for parents helping kids study for exams. Get down to the basics - get a handle on the basics of geometry, from lines, segments, and angles, to vertices, altitudes, and diagonals Conque
Arithmetic noncommutative geometry
Marcolli, Matilde
2005-01-01
Arithmetic noncommutative geometry denotes the use of ideas and tools from the field of noncommutative geometry, to address questions and reinterpret in a new perspective results and constructions from number theory and arithmetic algebraic geometry. This general philosophy is applied to the geometry and arithmetic of modular curves and to the fibers at archimedean places of arithmetic surfaces and varieties. The main reason why noncommutative geometry can be expected to say something about topics of arithmetic interest lies in the fact that it provides the right framework in which the tools of geometry continue to make sense on spaces that are very singular and apparently very far from the world of algebraic varieties. This provides a way of refining the boundary structure of certain classes of spaces that arise in the context of arithmetic geometry, such as moduli spaces (of which modular curves are the simplest case) or arithmetic varieties (completed by suitable "fibers at infinity"), by adding boundaries...
Zeelen, Jacques; van der Linden, Josje
2009-01-01
The intent of capacity building in international development cooperation is to enable people to control their own development. Important premises are ownership, choice and self-esteem. The authors analyse the dynamics of the enabling process in practice, based on their own experiences working for several years in universities in developing…
Papajohn, Dean
2006-01-01
While many institutions have utilized TOEFL scores for international admissions for many years, a speaking section has never before been a required part of TOEFL until the development of the iBT/Next Generation TOEFL. So institutions will need to determine how to set standards for the speaking section of TOEFL, also known as TOEFL Academic…
Fractal geometry mathematical foundations and applications
Falconer, Kenneth
2013-01-01
The seminal text on fractal geometry for students and researchers: extensively revised and updated with new material, notes and references that reflect recent directions. Interest in fractal geometry continues to grow rapidly, both as a subject that is fascinating in its own right and as a concept that is central to many areas of mathematics, science and scientific research. Since its initial publication in 1990 Fractal Geometry: Mathematical Foundations and Applications has become a seminal text on the mathematics of fractals. The book introduces and develops the general theory and applica
Moduli spaces in algebraic geometry
International Nuclear Information System (INIS)
Goettsche, L.
2000-01-01
This volume of the new series of lecture notes of the Abdus Salam International Centre for Theoretical Physics contains the lecture notes of the School on Algebraic Geometry which took place at the Abdus Salam International Centre for Theoretical Physics from 26 July to 13 August 1999. The school consisted of 2 weeks of lecture courses and one week of conference. The topic of the school was moduli spaces. More specifically the lectures were divided into three subtopics: principal bundles on Riemann surfaces, moduli spaces of vector bundles and sheaves on projective varieties, and moduli spaces of curves
Changing Role of China in the International Politics of the Last 15 Years in Reflection to the US
Directory of Open Access Journals (Sweden)
Szilárd Boros
2018-04-01
Full Text Available As a result of its 30-year successful economic growth, China has been gradually reshaping its international position. After the end of the Cold War, the US has been the unquestionable hegemon in the world politics and world economy, but after the economic crisis of 2007-08, the US hegemonic power is slowly eroding, the country’s capabilities in shaping world politics are decreasing and the international order, led by the US, is in disarray. On the other hand, China has made enormous efforts to reinforce its international positions over the last decade, which suits more to its growing economic power and own interests. The first part of the paper looks into the main theories on the two major powers’ possible future relations. In the second and third part of the paper, theories are being examined on practical bases; on the one hand we look at their relative explaining strength using a geopolitical power index, on the other hand, we briefly analyse main events and processes in their bilateral relations of the last decade to see how their relation is formed dynamically. In the summary, the paper attempts to outline scenarios on how their relation will evolve in the future.
Loignon, Christine; Gottin, Thomas; Valois, Carol; Couturier, François; Williams, Robert; Roy, Pierre-Michel
2016-11-01
To explore the perceived effect of an elective international health rotation on family medicine resident learning. Qualitative, collaborative study based on semistructured interviews. Quebec. A sample of 12 family medicine residents and 9 rotation supervisors (N = 21). Semistructured interviews of residents and rotation supervisors. Residents and supervisors alike reported that their technical skills and relationship skills had benefited. All increased their knowledge of tropical pathologies and learned to expand their clinical examinations. They benefited from having very rich interactions in other care settings, working with vulnerable populations. The rotations had their greatest effect on relationship skills (communication, empathy, etc) and the ability to work with vulnerable patients. All of the participants were exposed to local therapies and local interpretations of disease symptoms and pathogenesis. The findings of this study will have a considerable effect on pedagogy. The residents' experiences of their international health rotations and what they learned in terms of medical skills and pedagogic approaches in working with patients are described. Using a collaborative approach with the rotation supervisors, the data were triangulated and the benefits of an international rotation on academic training were more accurately defined. The findings can now be used to enrich academic programs in social and preventive medicine and more adequately prepare future family physicians for work in various social and cultural settings. Copyright© the College of Family Physicians of Canada.
Wave reflections from breakwaters
Dickson, William S.
1994-01-01
A new method is presented for estimating the reflection of a random, multi-directional sea from a coastal structure. The technique is applicable to an array of wave gauges of arbitrary geometry deployed seaward of the reflector. An expansion for small oblique wave incidence angles is used to derive an approximate relationship between measured array cross-spectra and a small number of parameters that describe the incident wave properties and the reflectivity of the structure. Model tests with ...
Kivioja, Antti; Hartus, Timo; Vuorinen, Tapani; Gane, Patrick; Jääskeläinen, Anna-Stiina
2013-06-01
The interactive behavior of ink constituents with porous substrates during and after the offset print process has an important effect on the quality of printed products. To help elucidate the distribution of ink components between the retained ink layer and the substrate, a variety of spectroscopic and microscopic analysis techniques have been developed. This paper describes for the first time the use of total internal reflection (TIR) Raman spectroscopy to analyze the penetration behavior of separated offset ink components (linseed oil, solid color pigment) in coated papers providing chemically intrinsic information rapidly, nondestructively, and with minimal sample preparation. In addition, the already widely applied technique of attenuated total reflection infrared spectroscopy (ATR-IR) was evaluated in parallel and compared. The results of the ATR-IR Raman clearly revealed an improvement in uppermost depth resolution compared with values previously published from other nondestructive techniques, and the method is shown to be capable of providing new knowledge of the setting of thin (0.25-2 μm) offset ink films, allowing the spreading and the penetration behavior on physically different paper coating surfaces to be studied.
Bárány, Imre; Vilcu, Costin
2016-01-01
This volume presents easy-to-understand yet surprising properties obtained using topological, geometric and graph theoretic tools in the areas covered by the Geometry Conference that took place in Mulhouse, France from September 7–11, 2014 in honour of Tudor Zamfirescu on the occasion of his 70th anniversary. The contributions address subjects in convexity and discrete geometry, in distance geometry or with geometrical flavor in combinatorics, graph theory or non-linear analysis. Written by top experts, these papers highlight the close connections between these fields, as well as ties to other domains of geometry and their reciprocal influence. They offer an overview on recent developments in geometry and its border with discrete mathematics, and provide answers to several open questions. The volume addresses a large audience in mathematics, including researchers and graduate students interested in geometry and geometrical problems.
Solar photovoltaic reflective trough collection structure
Anderson, Benjamin J.; Sweatt, William C.; Okandan, Murat; Nielson, Gregory N.
2015-11-19
A photovoltaic (PV) solar concentration structure having at least two troughs encapsulated in a rectangular parallelepiped optical plastic structure, with the troughs filled with an optical plastic material, the troughs each having a reflective internal surface and approximately parabolic geometry, and the troughs each including photovoltaic cells situated so that light impinging on the optical plastic material will be concentrated onto the photovoltaic cells. Multiple structures can be connected to provide a solar photovoltaic collection system that provides portable, efficient, low-cost electrical power.
Bhatia, Rajendra
2013-01-01
This book is an outcome of the Indo-French Workshop on Matrix Information Geometries (MIG): Applications in Sensor and Cognitive Systems Engineering, which was held in Ecole Polytechnique and Thales Research and Technology Center, Palaiseau, France, in February 23-25, 2011. The workshop was generously funded by the Indo-French Centre for the Promotion of Advanced Research (IFCPAR). During the event, 22 renowned invited french or indian speakers gave lectures on their areas of expertise within the field of matrix analysis or processing. From these talks, a total of 17 original contribution or state-of-the-art chapters have been assembled in this volume. All articles were thoroughly peer-reviewed and improved, according to the suggestions of the international referees. The 17 contributions presented are organized in three parts: (1) State-of-the-art surveys & original matrix theory work, (2) Advanced matrix theory for radar processing, and (3) Matrix-based signal processing applications.
Algorithms in Algebraic Geometry
Dickenstein, Alicia; Sommese, Andrew J
2008-01-01
In the last decade, there has been a burgeoning of activity in the design and implementation of algorithms for algebraic geometric computation. Some of these algorithms were originally designed for abstract algebraic geometry, but now are of interest for use in applications and some of these algorithms were originally designed for applications, but now are of interest for use in abstract algebraic geometry. The workshop on Algorithms in Algebraic Geometry that was held in the framework of the IMA Annual Program Year in Applications of Algebraic Geometry by the Institute for Mathematics and Its
O'Leary, Michael
2010-01-01
Guides readers through the development of geometry and basic proof writing using a historical approach to the topic. In an effort to fully appreciate the logic and structure of geometric proofs, Revolutions of Geometry places proofs into the context of geometry's history, helping readers to understand that proof writing is crucial to the job of a mathematician. Written for students and educators of mathematics alike, the book guides readers through the rich history and influential works, from ancient times to the present, behind the development of geometry. As a result, readers are successfull
Fundamental concepts of geometry
Meserve, Bruce E
1983-01-01
Demonstrates relationships between different types of geometry. Provides excellent overview of the foundations and historical evolution of geometrical concepts. Exercises (no solutions). Includes 98 illustrations.
Developments in special geometry
International Nuclear Information System (INIS)
Mohaupt, Thomas; Vaughan, Owen
2012-01-01
We review the special geometry of N = 2 supersymmetric vector and hypermultiplets with emphasis on recent developments and applications. A new formulation of the local c-map based on the Hesse potential and special real coordinates is presented. Other recent developments include the Euclidean version of special geometry, and generalizations of special geometry to non-supersymmetric theories. As applications we discuss the proof that the local r-map and c-map preserve geodesic completeness, and the construction of four- and five-dimensional static solutions through dimensional reduction over time. The shared features of the real, complex and quaternionic version of special geometry are stressed throughout.
Fujinami, Taku; Kigami, Hiroshi; Unno, Noriyuki; Taniguchi, Jun; Satake, Shin-ichi
2018-03-01
Total internal reflection fluorescence microscopy (TIRFM) is a promising method for measuring fluid flow close to a wall with nanoscale resolution in a process that is termed "multilayer nanoparticle image velocimetry" (MnPIV). TIRFM uses evanescent light that is generated on a substrate (typically a glass slide) by total internal reflection of light. Many researchers have previously studied x-y-z (3D) flows of water close to flat glass slides using MnPIV. On the other hand, a fluid flow close to a structured surface is also important. To measure flows of water near micro-patterns, we previously developed an MnPIV technique that uses a refractive-index-matching method. In previous study, the micropattern is made of a thermoplastic material with a refractive index that closely matches that of water. In this study, ultraviolet nanoimprint lithography was used for fabricating the appropriate micro-patterns because this technique can fabricate a pattern with a high resolution. As a result, we succeeded in performing MnPIV in water with a circular hole array pattern made by ultraviolet nanoimprint using a refractive-index-matching method. We believe that this technique will be helpful in elucidating fluid flows around microstructures.
International Nuclear Information System (INIS)
Lizana, A; Foldyna, M; Garcia-Caurel, E; Stchakovsky, M; Georges, B; Nicolas, D
2013-01-01
High sensitivity of spectroscopic ellipsometry and reflectometry for the characterization of thin films can strongly decrease when layers, typically metals, absorb a significant fraction of the light. In this paper, we propose a solution to overcome this drawback using total internal reflection ellipsometry (TIRE) and exciting a surface longitudinal wave: a plasmon-polariton. As in the attenuated total reflectance technique, TIRE exploits a minimum in the intensity of reflected transversal magnetic (TM) polarized light and enhances the sensitivity of standard methods to thicknesses of absorbing films. Samples under study were stacks of three films, ZnO : Al/Ag/ZnO : Al, deposited on glass substrates. The thickness of the silver layer varied from sample to sample. We performed measurements with a UV–visible phase-modulated ellipsometer, an IR Mueller ellipsometer and a UV–NIR reflectometer. We used the variance–covariance formalism to evaluate the sensitivity of the ellipsometric data to different parameters of the optical model. Results have shown that using TIRE doubled the sensitivity to the silver layer thickness when compared with the standard ellipsometry. Moreover, the thickness of the ZnO : Al layer below the silver layer can be reliably quantified, unlike for the fit of the standard ellipsometry data, which is limited by the absorption of the silver layer. (paper)
Lizana, A.; Foldyna, M.; Stchakovsky, M.; Georges, B.; Nicolas, D.; Garcia-Caurel, E.
2013-03-01
High sensitivity of spectroscopic ellipsometry and reflectometry for the characterization of thin films can strongly decrease when layers, typically metals, absorb a significant fraction of the light. In this paper, we propose a solution to overcome this drawback using total internal reflection ellipsometry (TIRE) and exciting a surface longitudinal wave: a plasmon-polariton. As in the attenuated total reflectance technique, TIRE exploits a minimum in the intensity of reflected transversal magnetic (TM) polarized light and enhances the sensitivity of standard methods to thicknesses of absorbing films. Samples under study were stacks of three films, ZnO : Al/Ag/ZnO : Al, deposited on glass substrates. The thickness of the silver layer varied from sample to sample. We performed measurements with a UV-visible phase-modulated ellipsometer, an IR Mueller ellipsometer and a UV-NIR reflectometer. We used the variance-covariance formalism to evaluate the sensitivity of the ellipsometric data to different parameters of the optical model. Results have shown that using TIRE doubled the sensitivity to the silver layer thickness when compared with the standard ellipsometry. Moreover, the thickness of the ZnO : Al layer below the silver layer can be reliably quantified, unlike for the fit of the standard ellipsometry data, which is limited by the absorption of the silver layer.
Special metrics and group actions in geometry
Fino, Anna; Musso, Emilio; Podestà, Fabio; Vezzoni, Luigi
2017-01-01
The volume is a follow-up to the INdAM meeting “Special metrics and quaternionic geometry” held in Rome in November 2015. It offers a panoramic view of a selection of cutting-edge topics in differential geometry, including 4-manifolds, quaternionic and octonionic geometry, twistor spaces, harmonic maps, spinors, complex and conformal geometry, homogeneous spaces and nilmanifolds, special geometries in dimensions 5–8, gauge theory, symplectic and toric manifolds, exceptional holonomy and integrable systems. The workshop was held in honor of Simon Salamon, a leading international scholar at the forefront of academic research who has made significant contributions to all these subjects. The articles published here represent a compelling testimony to Salamon’s profound and longstanding impact on the mathematical community. Target readership includes graduate students and researchers working in Riemannian and complex geometry, Lie theory and mathematical physics.
Directory of Open Access Journals (Sweden)
Wederson Rufino dos Santos
2010-07-01
Full Text Available This paper reviews the debate on the social model of disability has influenced conceptions of the International Classification of Functioning, Disability and Health adopted by the World Health Organization in 2001 and adopted in Brazil in 2007, through the law of the Continuous Cash Benefit. The BPC is a major social policy of income transfer to poor disabled people, affecting over one million and half disabled people in the country. Since 2009, the evaluation of persons with disabilities for the BPC will make by medical and social skills targeted by ICF. Will be demonstrated that, although the adoption of the ICF maybe to represent regard to how to understand disability as social inequality, the adoption of the ICF by the law of the BPC will face challenges in ensuring the right to dignity of disabled people.
Spencer, Phoebe R; Sanders, Katherine A; Judge, Debra S
2018-02-01
Population-specific growth references are important in understanding local growth variation, especially in developing countries where child growth is poor and the need for effective health interventions is high. In this article, we use mixed longitudinal data to calculate the first growth curves for rural East Timorese children to identify where, during development, deviation from the international standards occurs. Over an eight-year period, 1,245 children from two ecologically distinct rural areas of Timor-Leste were measured a total of 4,904 times. We compared growth to the World Health Organization (WHO) standards using z-scores, and modeled height and weight velocity using the SuperImposition by Translation And Rotation (SITAR) method. Using the Generalized Additive Model for Location, Scale and Shape (GAMLSS) method, we created the first growth curves for rural Timorese children for height, weight and body mass index (BMI). Relative to the WHO standards, children show early-life growth faltering, and stunting throughout childhood and adolescence. The median height and weight for this population tracks below the WHO fifth centile. Males have poorer growth than females in both z-BMI (p = .001) and z-height-for-age (p = .018) and, unlike females, continue to grow into adulthood. This is the most comprehensive investigation to date of rural Timorese children's growth, and the growth curves created may potentially be used to identify future secular trends in growth as the country develops. We show significant deviation from the international standard that becomes most pronounced at adolescence, similar to the growth of other Asian populations. Males and females show different growth responses to challenging conditions in this population. © 2017 Wiley Periodicals, Inc.
Directory of Open Access Journals (Sweden)
Sérgio Carvalho Benício de Mello
2011-03-01
Full Text Available Internal marketing perspective has gaining primordial space. It happens through an interdisciplinary process with human management discipline and is based on the assumption that a significant part of the organizational success depends on the attitudes, commitment and performance of people in an organization, above all the ones that interact with the customers. Assuming the premise that such procedure depends on the relationship between the contact employees and the customers of an organization, we revise in this essay fundamental notions of interpresonel relationships to discuss the role of the internal marketing in the formation of employees that becomes reflexive subjects. We understand such premise as a fundamental characteristic for those to carry out his/her role in a conscious way. Our conclusion is a theoretical proposal of how this can be developed.A perspectiva do marketing interno tem ganho espaço primordial. Isto ocorre por meio de um processo interdisciplinar com a gestão de pessoas, por se compreender que parte do êxito organizacional dependa das atitudes, do comprometimento e do desempenho de todos os envolvidos numa organização, sobretudo os que interagem com os clientes. Assumindo a premissa de que tal procedimento dependa do relacionamento entre o funcionário de contato e os clientes de uma organização, neste ensaio teórico revisamos noções fundamentais do conhecimento acerca das relações interpessoais para discutir o papel do marketing interno na formação de funcionários que se tornem sujeitos reflexivos. Tal premissa é por nos compreendida como característica fundamental para que estes desempenhem seu papel de forma consciente. Nossa chegada é uma proposta teórica de como isto possa ser desenvolvido.
Geometry of multihadron production
Energy Technology Data Exchange (ETDEWEB)
Bjorken, J.D.
1994-10-01
This summary talk only reviews a small sample of topics featured at this symposium: Introduction; The Geometry and Geography of Phase space; Space-Time Geometry and HBT; Multiplicities, Intermittency, Correlations; Disoriented Chiral Condensate; Deep Inelastic Scattering at HERA; and Other Contributions.
1996-01-01
Designs and Finite Geometries brings together in one place important contributions and up-to-date research results in this important area of mathematics. Designs and Finite Geometries serves as an excellent reference, providing insight into some of the most important research issues in the field.
Geometry of multihadron production
International Nuclear Information System (INIS)
Bjorken, J.D.
1994-10-01
This summary talk only reviews a small sample of topics featured at this symposium: Introduction; The Geometry and Geography of Phase space; Space-Time Geometry and HBT; Multiplicities, Intermittency, Correlations; Disoriented Chiral Condensate; Deep Inelastic Scattering at HERA; and Other Contributions
Morris, Barbara H.
2004-01-01
This article describes a geometry project that used the beauty of stained-glass-window designs to teach middle school students about geometric figures and concepts. Three honors prealgebra teachers and a middle school mathematics gifted intervention specialist created a geometry project that covered the curriculum and also assessed students'…
Fractal geometry and computer graphics
Sakas, Georgios; Peitgen, Heinz-Otto; Englert, Gabriele
1992-01-01
Fractal geometry has become popular in the last 15 years, its applications can be found in technology, science, or even arts. Fractal methods and formalism are seen today as a general, abstract, but nevertheless practical instrument for the description of nature in a wide sense. But it was Computer Graphics which made possible the increasing popularity of fractals several years ago, and long after their mathematical formulation. The two disciplines are tightly linked. The book contains the scientificcontributions presented in an international workshop in the "Computer Graphics Center" in Darmstadt, Germany. The target of the workshop was to present the wide spectrum of interrelationships and interactions between Fractal Geometry and Computer Graphics. The topics vary from fundamentals and new theoretical results to various applications and systems development. All contributions are original, unpublished papers.The presentations have been discussed in two working groups; the discussion results, together with a...
Foliation theory in algebraic geometry
McKernan, James; Pereira, Jorge
2016-01-01
Featuring a blend of original research papers and comprehensive surveys from an international team of leading researchers in the thriving fields of foliation theory, holomorphic foliations, and birational geometry, this book presents the proceedings of the conference "Foliation Theory in Algebraic Geometry," hosted by the Simons Foundation in New York City in September 2013. Topics covered include: Fano and del Pezzo foliations; the cone theorem and rank one foliations; the structure of symmetric differentials on a smooth complex surface and a local structure theorem for closed symmetric differentials of rank two; an overview of lifting symmetric differentials from varieties with canonical singularities and the applications to the classification of AT bundles on singular varieties; an overview of the powerful theory of the variety of minimal rational tangents introduced by Hwang and Mok; recent examples of varieties which are hyperbolic and yet the Green-Griffiths locus is the whole of X; and a classificati...
Loi, Shyeh Tjing; Papaloizou, John C. B.
2018-04-01
The spectrum of oscillation modes of a star provides information not only about its material properties (e.g. mean density), but also its symmetries. Spherical symmetry can be broken by rotation and/or magnetic fields. It has been postulated that strong magnetic fields in the cores of some red giants are responsible for their anomalously weak dipole mode amplitudes (the "dipole dichotomy" problem), but a detailed understanding of how gravity waves interact with strong fields is thus far lacking. In this work, we attack the problem through a variety of analytical and numerical techniques, applied to a localised region centred on a null line of a confined axisymmetric magnetic field which is approximated as being cylindrically symmetric. We uncover a rich variety of phenomena that manifest when the field strength exceeds a critical value, beyond which the symmetry is drastically broken by the Lorentz force. When this threshold is reached, the spatial structure of the g-modes becomes heavily altered. The dynamics of wave packet propagation transitions from regular to chaotic, which is expected to fundamentally change the organisation of the mode spectrum. In addition, depending on their frequency and the orientation of field lines with respect to the stratification, waves impinging on different parts of the magnetised region are found to undergo either reflection or trapping. Trapping regions provide an avenue for energy loss through Alfvén wave phase mixing. Our results may find application in various astrophysical contexts, including the dipole dichotomy problem, the solar interior, and compact star oscillations.
Energy Technology Data Exchange (ETDEWEB)
Grotz, Andreas
2011-10-07
In this thesis, a formulation of a Lorentzian quantum geometry based on the framework of causal fermion systems is proposed. After giving the general definition of causal fermion systems, we deduce space-time as a topological space with an underlying causal structure. Restricting attention to systems of spin dimension two, we derive the objects of our quantum geometry: the spin space, the tangent space endowed with a Lorentzian metric, connection and curvature. In order to get the correspondence to classical differential geometry, we construct examples of causal fermion systems by regularizing Dirac sea configurations in Minkowski space and on a globally hyperbolic Lorentzian manifold. When removing the regularization, the objects of our quantum geometry reduce to the common objects of spin geometry on Lorentzian manifolds, up to higher order curvature corrections.
Methods of information geometry
Amari, Shun-Ichi
2000-01-01
Information geometry provides the mathematical sciences with a new framework of analysis. It has emerged from the investigation of the natural differential geometric structure on manifolds of probability distributions, which consists of a Riemannian metric defined by the Fisher information and a one-parameter family of affine connections called the \\alpha-connections. The duality between the \\alpha-connection and the (-\\alpha)-connection together with the metric play an essential role in this geometry. This kind of duality, having emerged from manifolds of probability distributions, is ubiquitous, appearing in a variety of problems which might have no explicit relation to probability theory. Through the duality, it is possible to analyze various fundamental problems in a unified perspective. The first half of this book is devoted to a comprehensive introduction to the mathematical foundation of information geometry, including preliminaries from differential geometry, the geometry of manifolds or probability d...
International Nuclear Information System (INIS)
Grotz, Andreas
2011-01-01
In this thesis, a formulation of a Lorentzian quantum geometry based on the framework of causal fermion systems is proposed. After giving the general definition of causal fermion systems, we deduce space-time as a topological space with an underlying causal structure. Restricting attention to systems of spin dimension two, we derive the objects of our quantum geometry: the spin space, the tangent space endowed with a Lorentzian metric, connection and curvature. In order to get the correspondence to classical differential geometry, we construct examples of causal fermion systems by regularizing Dirac sea configurations in Minkowski space and on a globally hyperbolic Lorentzian manifold. When removing the regularization, the objects of our quantum geometry reduce to the common objects of spin geometry on Lorentzian manifolds, up to higher order curvature corrections.
International Nuclear Information System (INIS)
ElBaradei, M.
2005-01-01
Emerging nuclear challenges are proliferation of nuclear weapons and sensitive nuclear technologies, emergence of nuclear clandestine procurement networks in nuclear materials and equipment and the sluggishment in nuclear disarmament. Practical steps to address them are 1) better control of access to nuclear fuel cycle technology; 2) supporting effective nuclear verification; 3) strengthening the credibility of enforcement mechanisms; 4) protecting nuclear material and 5) developing an alternative approach to collective security. For better control of access to nuclear fuel cycle technology a group of international experts proposes to a) provide assurance of supply of reactor technology and nuclear fuel; b) accept a time-limited moratorium (of perhaps 5-10 years) on new uranium enrichment and plutonium separation facilities - at the very least for countries that do not currently have such technologies; c) establish a framework for multilateral management and control of the 'back end' of the fuel cycle (i.e. spent fuel reprocessing and waste disposal); and d) create a similar framework for multilateral management and control of the 'front end' of the fuel cycle (i.e. enrichment and fuel production). The effectiveness of nuclear verification depends on the extend of access to information and locations in a given country and inspections can only verify what countries declare. The expanded access provided by the Additional Protocol to safeguards agreements enables the Agency to verify possible undeclared activities however both safeguards agreements are focused on nuclear material and therefore the Agency's authority to investigate possible parallel weaponization activity is limited. In addition only 70 countries have the additional protocol on force. A dditional transparency measures' may be required as well as additional funding to support R and D on new technologies for detecting clandestine nuclear facilities and activity. An important step to address the nuclear
Directory of Open Access Journals (Sweden)
Wagner Moura Lamounier
2008-10-01
Full Text Available In this research, we analyzed the short and long term interdependence and relationship between the stock indices of the major emerging capital markets and the major developed markets for the period 1995-2005. The aim was to verify the existence and the dynamics of the “contagion” between the markets, or if the occurrence of crises and changes in the behavior of a market would have impacts on the behavior of the others. In the development of the work, we applied the methodology of the Vector Error Correction Model (VEC. We found the presence of cointegrating relationships between the markets analyzed, but was able to see that, despite being cointegrated markets, investors could beneﬁt from international diversiﬁcation of portfolios. That’s because the speed of adjustment of the long-term ratio of cointegration between the markets was low for the period analyzed. Accordingly, investors would have the opportunity to reduce risk by diversifying their portfolios.
Hoang, U; Luna, P; Russell, P; Bergonzi-King, L; Ashton, J; McCarthy, C; Donovan, H; Inman, P; Seminog, O; Botchway, S
2018-03-01
Film competitions can be a helpful method to understand issues of quality in health films. In this paper, we describe the development and use of explicit quality criteria to identify the 'best' films for the first ever international public health film competition. A film selection committee encompassing a range of stakeholders was compiled. The committee drew up 10 explicit quality criteria to judge films drawing upon other film festival's selection criteria. These criteria were then applied to a broad range of health-related films entered into a film competition to select the 'best' film to screen. Eighty-four films from 20 different countries were submitted to the public health film competition. The originality of the subject covered by the film, the public health importance of the issue and story-telling approach in the film were found to be the most discriminatory criteria to select films. Selection of health films for festivals can be undertaken using explicit quality criteria. There are a number of advantages to such an approach; however, explicit selection involves a large commitment of resources from film festival organizers and there is further research required to test the validity of the quality criteria applied to health-related films.
Geometry on the space of geometries
International Nuclear Information System (INIS)
Christodoulakis, T.; Zanelli, J.
1988-06-01
We discuss the geometric structure of the configuration space of pure gravity. This is an infinite dimensional manifold, M, where each point represents one spatial geometry g ij (x). The metric on M is dictated by geometrodynamics, and from it, the Christoffel symbols and Riemann tensor can be found. A ''free geometry'' tracing a geodesic on the manifold describes the time evolution of space in the strong gravity limit. In a regularization previously introduced by the authors, it is found that M does not have the same dimensionality, D, everywhere, and that D is not a scalar, although it is covariantly constant. In this regularization, it is seen that the path integral measure can be absorbed in a renormalization of the cosmological constant. (author). 19 refs
Complex and symplectic geometry
Medori, Costantino; Tomassini, Adriano
2017-01-01
This book arises from the INdAM Meeting "Complex and Symplectic Geometry", which was held in Cortona in June 2016. Several leading specialists, including young researchers, in the field of complex and symplectic geometry, present the state of the art of their research on topics such as the cohomology of complex manifolds; analytic techniques in Kähler and non-Kähler geometry; almost-complex and symplectic structures; special structures on complex manifolds; and deformations of complex objects. The work is intended for researchers in these areas.
Kulczycki, Stefan
2008-01-01
This accessible approach features two varieties of proofs: stereometric and planimetric, as well as elementary proofs that employ only the simplest properties of the plane. A short history of geometry precedes a systematic exposition of the principles of non-Euclidean geometry.Starting with fundamental assumptions, the author examines the theorems of Hjelmslev, mapping a plane into a circle, the angle of parallelism and area of a polygon, regular polygons, straight lines and planes in space, and the horosphere. Further development of the theory covers hyperbolic functions, the geometry of suff
Worldsheet geometries of ambitwistor string
Energy Technology Data Exchange (ETDEWEB)
Ohmori, Kantaro [Department of Physics, the University of Tokyo,Hongo, Bunkyo-ku, Tokyo 133-0022 (Japan)
2015-06-12
Mason and Skinner proposed the ambitwistor string theory which directly reproduces the formulas for the amplitudes of massless particles proposed by Cachazo, He and Yuan. In this paper we discuss geometries of the moduli space of worldsheets associated to the bosonic or the RNS ambitwistor string. Further, we investigate the factorization properties of the amplitudes when an internal momentum is near on-shell in the abstract CFT language. Along the way, we propose the existence of the ambitwistor strings with three or four fermionic worldsheet currents.
Le, Nam Cao Hoai; Yokokawa, Ryuji; Dao, Dzung Viet; Nguyen, Thien Duy; Wells, John C; Sugiyama, Susumu
2009-01-21
A poly(dimethylsiloxane) (PDMS) chip for Total Internal Reflection (TIR)-based imaging and detection has been developed using Si bulk micromachining and PDMS casting. In this paper, we report the applications of the chip on both inverted and upright fluorescent microscopes and confirm that two types of sample delivery platforms, PDMS microchannel and glass microchannel, can be easily integrated depending on the magnification of an objective lens needed to visualize a sample. Although any device configuration can be achievable, here we performed two experiments to demonstrate the versatility of the microfluidic TIR-based devices. The first experiment was velocity measurement of Nile red microbeads with nominal diameter of 500 nm in a pressure-driven flow. The time-sequenced fluorescent images of microbeads, illuminated by an evanescent field, were cross-correlated by a Particle Image Velocimetry (PIV) program to obtain near-wall velocity field of the microbeads at various flow rates from 500 nl/min to 3000 nl/min. We then evaluated the capabilities of the device for Single Molecule Detection (SMD) of fluorescently labeled DNA molecules from 30 bp to 48.5 kbp and confirm that DNA molecules as short as 1105 bp were detectable. Our versatile, integrated device could provide low-cost and fast accessibility to Total Internal Reflection Fluorescent Microscopy (TIRFM) on both conventional upright and inverted microscopes. It could also be a useful component in a Micro-Total Analysis System (micro-TAS) to analyze nanoparticles or biomolecules near-wall transport or motion.
Roe, John
2003-01-01
Coarse geometry is the study of spaces (particularly metric spaces) from a 'large scale' point of view, so that two spaces that look the same from a great distance are actually equivalent. This point of view is effective because it is often true that the relevant geometric properties of metric spaces are determined by their coarse geometry. Two examples of important uses of coarse geometry are Gromov's beautiful notion of a hyperbolic group and Mostow's proof of his famous rigidity theorem. The first few chapters of the book provide a general perspective on coarse structures. Even when only metric coarse structures are in view, the abstract framework brings the same simplification as does the passage from epsilons and deltas to open sets when speaking of continuity. The middle section reviews notions of negative curvature and rigidity. Modern interest in large scale geometry derives in large part from Mostow's rigidity theorem and from Gromov's subsequent 'large scale' rendition of the crucial properties of n...
Lectures on Symplectic Geometry
Silva, Ana Cannas
2001-01-01
The goal of these notes is to provide a fast introduction to symplectic geometry for graduate students with some knowledge of differential geometry, de Rham theory and classical Lie groups. This text addresses symplectomorphisms, local forms, contact manifolds, compatible almost complex structures, Kaehler manifolds, hamiltonian mechanics, moment maps, symplectic reduction and symplectic toric manifolds. It contains guided problems, called homework, designed to complement the exposition or extend the reader's understanding. There are by now excellent references on symplectic geometry, a subset of which is in the bibliography of this book. However, the most efficient introduction to a subject is often a short elementary treatment, and these notes attempt to serve that purpose. This text provides a taste of areas of current research and will prepare the reader to explore recent papers and extensive books on symplectic geometry where the pace is much faster. For this reprint numerous corrections and cl...
Kollár, János
1997-01-01
This volume contains the lectures presented at the third Regional Geometry Institute at Park City in 1993. The lectures provide an introduction to the subject, complex algebraic geometry, making the book suitable as a text for second- and third-year graduate students. The book deals with topics in algebraic geometry where one can reach the level of current research while starting with the basics. Topics covered include the theory of surfaces from the viewpoint of recent higher-dimensional developments, providing an excellent introduction to more advanced topics such as the minimal model program. Also included is an introduction to Hodge theory and intersection homology based on the simple topological ideas of Lefschetz and an overview of the recent interactions between algebraic geometry and theoretical physics, which involve mirror symmetry and string theory.
DEFF Research Database (Denmark)
Kokkendorff, Simon Lyngby
2002-01-01
The subject of this Ph.D.-thesis is somewhere in between continuous and discrete geometry. Chapter 2 treats the geometry of finite point sets in semi-Riemannian hyperquadrics,using a matrix whose entries are a trigonometric function of relative distances in a given point set. The distance...... to the geometry of a simplex in a semi-Riemannian hyperquadric. In chapter 3 we study which finite metric spaces that are realizable in a hyperbolic space in the limit where curvature goes to -∞. We show that such spaces are the so called leaf spaces, the set of degree 1 vertices of weighted trees. We also...... establish results on the limiting geometry of such an isometrically realized leaf space simplex in hyperbolic space, when curvature goes to -∞. Chapter 4 discusses negative type of metric spaces. We give a measure theoretic treatment of this concept and related invariants. The theory developed...
Busemann, Herbert
2005-01-01
A comprehensive approach to qualitative problems in intrinsic differential geometry, this text examines Desarguesian spaces, perpendiculars and parallels, covering spaces, the influence of the sign of the curvature on geodesics, more. 1955 edition. Includes 66 figures.
Introduction to tropical geometry
Maclagan, Diane
2015-01-01
Tropical geometry is a combinatorial shadow of algebraic geometry, offering new polyhedral tools to compute invariants of algebraic varieties. It is based on tropical algebra, where the sum of two numbers is their minimum and the product is their sum. This turns polynomials into piecewise-linear functions, and their zero sets into polyhedral complexes. These tropical varieties retain a surprising amount of information about their classical counterparts. Tropical geometry is a young subject that has undergone a rapid development since the beginning of the 21st century. While establishing itself as an area in its own right, deep connections have been made to many branches of pure and applied mathematics. This book offers a self-contained introduction to tropical geometry, suitable as a course text for beginning graduate students. Proofs are provided for the main results, such as the Fundamental Theorem and the Structure Theorem. Numerous examples and explicit computations illustrate the main concepts. Each of t...
Rudiments of algebraic geometry
Jenner, WE
2017-01-01
Aimed at advanced undergraduate students of mathematics, this concise text covers the basics of algebraic geometry. Topics include affine spaces, projective spaces, rational curves, algebraic sets with group structure, more. 1963 edition.
Implosions and hypertoric geometry
DEFF Research Database (Denmark)
Dancer, A.; Kirwan, F.; Swann, A.
2013-01-01
The geometry of the universal hyperkahler implosion for SU (n) is explored. In particular, we show that the universal hyperkahler implosion naturally contains a hypertoric variety described in terms of quivers. Furthermore, we discuss a gauge theoretic approach to hyperkahler implosion.......The geometry of the universal hyperkahler implosion for SU (n) is explored. In particular, we show that the universal hyperkahler implosion naturally contains a hypertoric variety described in terms of quivers. Furthermore, we discuss a gauge theoretic approach to hyperkahler implosion....
Intermediate algebra & analytic geometry
Gondin, William R
1967-01-01
Intermediate Algebra & Analytic Geometry Made Simple focuses on the principles, processes, calculations, and methodologies involved in intermediate algebra and analytic geometry. The publication first offers information on linear equations in two unknowns and variables, functions, and graphs. Discussions focus on graphic interpretations, explicit and implicit functions, first quadrant graphs, variables and functions, determinate and indeterminate systems, independent and dependent equations, and defective and redundant systems. The text then examines quadratic equations in one variable, system
Ceresole, Anna; Gnecchi, Alessandra; Marrani, Alessio
2013-01-01
We analyze some properties of the four dimensional supergravity theories which originate from five dimensions upon reduction. They generalize to N>2 extended supersymmetries the d-geometries with cubic prepotentials, familiar from N=2 special K\\"ahler geometry. We emphasize the role of a suitable parametrization of the scalar fields and the corresponding triangular symplectic basis. We also consider applications to the first order flow equations for non-BPS extremal black holes.
International Nuclear Information System (INIS)
Osborne, I; Brownson, E; Eulisse, G; Jones, C D; Sexton-Kennedy, E; Lange, D J
2014-01-01
CMS faces real challenges with upgrade of the CMS detector through 2020 and beyond. One of the challenges, from the software point of view, is managing upgrade simulations with the same software release as the 2013 scenario. We present the CMS geometry description software model, its integration with the CMS event setup and core software. The CMS geometry configuration and selection is implemented in Python. The tools collect the Python configuration fragments into a script used in CMS workflow. This flexible and automated geometry configuration allows choosing either transient or persistent version of the same scenario and specific version of the same scenario. We describe how the geometries are integrated and validated, and how we define and handle different geometry scenarios in simulation and reconstruction. We discuss how to transparently manage multiple incompatible geometries in the same software release. Several examples are shown based on current implementation assuring consistent choice of scenario conditions. The consequences and implications for multiple/different code algorithms are discussed.
Software Geometry in Simulations
Alion, Tyler; Viren, Brett; Junk, Tom
2015-04-01
The Long Baseline Neutrino Experiment (LBNE) involves many detectors. The experiment's near detector (ND) facility, may ultimately involve several detectors. The far detector (FD) will be significantly larger than any other Liquid Argon (LAr) detector yet constructed; many prototype detectors are being constructed and studied to motivate a plethora of proposed FD designs. Whether it be a constructed prototype or a proposed ND/FD design, every design must be simulated and analyzed. This presents a considerable challenge to LBNE software experts; each detector geometry must be described to the simulation software in an efficient way which allows for multiple authors to easily collaborate. Furthermore, different geometry versions must be tracked throughout their use. We present a framework called General Geometry Description (GGD), written and developed by LBNE software collaborators for managing software to generate geometries. Though GGD is flexible enough to be used by any experiment working with detectors, we present it's first use in generating Geometry Description Markup Language (GDML) files to interface with LArSoft, a framework of detector simulations, event reconstruction, and data analyses written for all LAr technology users at Fermilab. Brett is the other of the framework discussed here, the General Geometry Description (GGD).
Introduction to combinatorial geometry
International Nuclear Information System (INIS)
Gabriel, T.A.; Emmett, M.B.
1985-01-01
The combinatorial geometry package as used in many three-dimensional multimedia Monte Carlo radiation transport codes, such as HETC, MORSE, and EGS, is becoming the preferred way to describe simple and complicated systems. Just about any system can be modeled using the package with relatively few input statements. This can be contrasted against the older style geometry packages in which the required input statements could be large even for relatively simple systems. However, with advancements come some difficulties. The users of combinatorial geometry must be able to visualize more, and, in some instances, all of the system at a time. Errors can be introduced into the modeling which, though slight, and at times hard to detect, can have devastating effects on the calculated results. As with all modeling packages, the best way to learn the combinatorial geometry is to use it, first on a simple system then on more complicated systems. The basic technique for the description of the geometry consists of defining the location and shape of the various zones in terms of the intersections and unions of geometric bodies. The geometric bodies which are generally included in most combinatorial geometry packages are: (1) box, (2) right parallelepiped, (3) sphere, (4) right circular cylinder, (5) right elliptic cylinder, (6) ellipsoid, (7) truncated right cone, (8) right angle wedge, and (9) arbitrary polyhedron. The data necessary to describe each of these bodies are given. As can be easily noted, there are some subsets included for simplicity
Global aspects of complex geometry
Catanese, Fabrizio; Huckleberry, Alan T
2006-01-01
Present an overview of developments in Complex Geometry. This book covers topics that range from curve and surface theory through special varieties in higher dimensions, moduli theory, Kahler geometry, and group actions to Hodge theory and characteristic p-geometry.
Sources of hyperbolic geometry
Stillwell, John
1996-01-01
This book presents, for the first time in English, the papers of Beltrami, Klein, and Poincaré that brought hyperbolic geometry into the mainstream of mathematics. A recognition of Beltrami comparable to that given the pioneering works of Bolyai and Lobachevsky seems long overdue-not only because Beltrami rescued hyperbolic geometry from oblivion by proving it to be logically consistent, but because he gave it a concrete meaning (a model) that made hyperbolic geometry part of ordinary mathematics. The models subsequently discovered by Klein and Poincaré brought hyperbolic geometry even further down to earth and paved the way for the current explosion of activity in low-dimensional geometry and topology. By placing the works of these three mathematicians side by side and providing commentaries, this book gives the student, historian, or professional geometer a bird's-eye view of one of the great episodes in mathematics. The unified setting and historical context reveal the insights of Beltrami, Klein, and Po...
International Nuclear Information System (INIS)
Jonsson, Rickard; Westman, Hans
2006-01-01
We show that by employing the standard projected curvature as a measure of spatial curvature, we can make a certain generalization of optical geometry (Abramowicz M A and Lasota J-P 1997 Class. Quantum Grav. A 14 23-30). This generalization applies to any spacetime that admits a hypersurface orthogonal shearfree congruence of worldlines. This is a somewhat larger class of spacetimes than the conformally static spacetimes assumed in standard optical geometry. In the generalized optical geometry, which in the generic case is time dependent, photons move with unit speed along spatial geodesics and the sideways force experienced by a particle following a spatially straight line is independent of the velocity. Also gyroscopes moving along spatial geodesics do not precess (relative to the forward direction). Gyroscopes that follow a curved spatial trajectory precess according to a very simple law of three-rotation. We also present an inertial force formalism in coordinate representation for this generalization. Furthermore, we show that by employing a new sense of spatial curvature (Jonsson R 2006 Class. Quantum Grav. 23 1)) closely connected to Fermat's principle, we can make a more extensive generalization of optical geometry that applies to arbitrary spacetimes. In general this optical geometry will be time dependent, but still geodesic photons move with unit speed and follow lines that are spatially straight in the new sense. Also, the sideways experienced (comoving) force on a test particle following a line that is straight in the new sense will be independent of the velocity
Alsdorf, Doug
1997-08-01
Migration of deep seismic data is often hindered by a narrow recording aperture (line length by record length) and a low signal-to-noise ratio. The severity of typical migration artifacts (e.g., lateral smearing of discontinuous reflections into synforms, "smiles") increases with travel time such that interpreters of deep seismic data have often substituted migrated line drawings for the actual sections. As part of Project INDEPTH (International Deep Profiling of Tibet and the Himalaya), a new migration method was developed to address both the noise and migration issues. The method works in the time-space domain and uses the simple, constant velocity, straight ray path to perform the migration. First, only amplitudes within a given range are retained for migration, thus avoiding high-amplitude noise bursts and low-amplitude background noise. Then, the local dip of a reflection is found by automatically fitting a straight line to the highest amplitudes within a small window (several time samples by several traces) and calculating the dip of the line using a constant velocity. Finally, using this dip, the method migrates a selected amplitude value. The dips, lateral positions, and depths of the migrated events compare very well with output from more conventional algorithms (e.g.,fk-Stolt, finite difference, etc.). The advantages of the new method include fewer artifacts, fast computer run times, low memory use and the ability to migrate long profiles and travel times (e.g., 50 s). The output of the method is a grid of migrated amplitudes (not wavelets) or dip values which is particularly effective for making small figures, such as those needed for publication. The principal disadvantage is the use of a constant migration velocity.
Computational synthetic geometry
Bokowski, Jürgen
1989-01-01
Computational synthetic geometry deals with methods for realizing abstract geometric objects in concrete vector spaces. This research monograph considers a large class of problems from convexity and discrete geometry including constructing convex polytopes from simplicial complexes, vector geometries from incidence structures and hyperplane arrangements from oriented matroids. It turns out that algorithms for these constructions exist if and only if arbitrary polynomial equations are decidable with respect to the underlying field. Besides such complexity theorems a variety of symbolic algorithms are discussed, and the methods are applied to obtain new mathematical results on convex polytopes, projective configurations and the combinatorics of Grassmann varieties. Finally algebraic varieties characterizing matroids and oriented matroids are introduced providing a new basis for applying computer algebra methods in this field. The necessary background knowledge is reviewed briefly. The text is accessible to stud...
Discrete and computational geometry
Devadoss, Satyan L
2011-01-01
Discrete geometry is a relatively new development in pure mathematics, while computational geometry is an emerging area in applications-driven computer science. Their intermingling has yielded exciting advances in recent years, yet what has been lacking until now is an undergraduate textbook that bridges the gap between the two. Discrete and Computational Geometry offers a comprehensive yet accessible introduction to this cutting-edge frontier of mathematics and computer science. This book covers traditional topics such as convex hulls, triangulations, and Voronoi diagrams, as well as more recent subjects like pseudotriangulations, curve reconstruction, and locked chains. It also touches on more advanced material, including Dehn invariants, associahedra, quasigeodesics, Morse theory, and the recent resolution of the Poincaré conjecture. Connections to real-world applications are made throughout, and algorithms are presented independently of any programming language. This richly illustrated textbook also fe...
Ochiai, T.; Nacher, J. C.
2011-09-01
Recently, the application of geometry and conformal mappings to artificial materials (metamaterials) has attracted the attention in various research communities. These materials, characterized by a unique man-made structure, have unusual optical properties, which materials found in nature do not exhibit. By applying the geometry and conformal mappings theory to metamaterial science, it may be possible to realize so-called "Harry Potter cloaking device". Although such a device is still in the science fiction realm, several works have shown that by using such metamaterials it may be possible to control the direction of the electromagnetic field at will. We could then make an object hidden inside of a cloaking device. Here, we will explain how to design invisibility device using differential geometry and conformal mappings.
2002-01-01
Discrete geometry investigates combinatorial properties of configurations of geometric objects. To a working mathematician or computer scientist, it offers sophisticated results and techniques of great diversity and it is a foundation for fields such as computational geometry or combinatorial optimization. This book is primarily a textbook introduction to various areas of discrete geometry. In each area, it explains several key results and methods, in an accessible and concrete manner. It also contains more advanced material in separate sections and thus it can serve as a collection of surveys in several narrower subfields. The main topics include: basics on convex sets, convex polytopes, and hyperplane arrangements; combinatorial complexity of geometric configurations; intersection patterns and transversals of convex sets; geometric Ramsey-type results; polyhedral combinatorics and high-dimensional convexity; and lastly, embeddings of finite metric spaces into normed spaces. Jiri Matousek is Professor of Com...
Zheng, Fangyang
2002-01-01
The theory of complex manifolds overlaps with several branches of mathematics, including differential geometry, algebraic geometry, several complex variables, global analysis, topology, algebraic number theory, and mathematical physics. Complex manifolds provide a rich class of geometric objects, for example the (common) zero locus of any generic set of complex polynomials is always a complex manifold. Yet complex manifolds behave differently than generic smooth manifolds; they are more coherent and fragile. The rich yet restrictive character of complex manifolds makes them a special and interesting object of study. This book is a self-contained graduate textbook that discusses the differential geometric aspects of complex manifolds. The first part contains standard materials from general topology, differentiable manifolds, and basic Riemannian geometry. The second part discusses complex manifolds and analytic varieties, sheaves and holomorphic vector bundles, and gives a brief account of the surface classifi...
Yale, Paul B
2012-01-01
This book is an introduction to the geometry of Euclidean, affine, and projective spaces with special emphasis on the important groups of symmetries of these spaces. The two major objectives of the text are to introduce the main ideas of affine and projective spaces and to develop facility in handling transformations and groups of transformations. Since there are many good texts on affine and projective planes, the author has concentrated on the n-dimensional cases.Designed to be used in advanced undergraduate mathematics or physics courses, the book focuses on ""practical geometry,"" emphasi
On relational nature of geometry of microphysics
International Nuclear Information System (INIS)
Chylinski, Z.
1985-11-01
A relativity principle and a curiosity of Galilei space-time is described. An internal space-time of R 4 relation is presented. Lorentz limit of R 4 geometry and a field theory is given. The sources of the effects of R 4 hypothesis are characterized. The completeness of quantum description is discussed. 32 refs. (A.S.)
Towards relativistic quantum geometry
Energy Technology Data Exchange (ETDEWEB)
Ridao, Luis Santiago [Instituto de Investigaciones Físicas de Mar del Plata (IFIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Mar del Plata (Argentina); Bellini, Mauricio, E-mail: mbellini@mdp.edu.ar [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, C.P. 7600, Mar del Plata (Argentina); Instituto de Investigaciones Físicas de Mar del Plata (IFIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Mar del Plata (Argentina)
2015-12-17
We obtain a gauge-invariant relativistic quantum geometry by using a Weylian-like manifold with a geometric scalar field which provides a gauge-invariant relativistic quantum theory in which the algebra of the Weylian-like field depends on observers. An example for a Reissner–Nordström black-hole is studied.
Multiplicity in difference geometry
Tomasic, Ivan
2011-01-01
We prove a first principle of preservation of multiplicity in difference geometry, paving the way for the development of a more general intersection theory. In particular, the fibres of a \\sigma-finite morphism between difference curves are all of the same size, when counted with correct multiplicities.
Spacetime and Euclidean geometry
Brill, Dieter; Jacobson, Ted
2006-04-01
Using only the principle of relativity and Euclidean geometry we show in this pedagogical article that the square of proper time or length in a two-dimensional spacetime diagram is proportional to the Euclidean area of the corresponding causal domain. We use this relation to derive the Minkowski line element by two geometric proofs of the spacetime Pythagoras theorem.
International Nuclear Information System (INIS)
Konopleva, N.P.
2009-01-01
The basic ideas of description methods of physical fields and elementary particle interactions are discussed. One of such ideas is the conception of space-time geometry. In this connection experimental measurement methods are analyzed. It is shown that measure procedures are the origin of geometrical axioms. The connection between space symmetry properties and the conservation laws is considered
Wares, Arsalan; Elstak, Iwan
2017-01-01
The purpose of this paper is to describe the mathematics that emanates from the construction of an origami box. We first construct a simple origami box from a rectangular sheet and then discuss some of the mathematical questions that arise in the context of geometry and algebra. The activity can be used as a context for illustrating how algebra…
MacKeown, P. K.
1984-01-01
Clarifies two concepts of gravity--those of a fictitious force and those of how space and time may have geometry. Reviews the position of Newton's theory of gravity in the context of special relativity and considers why gravity (as distinct from electromagnetics) lends itself to Einstein's revolutionary interpretation. (JN)
DEFF Research Database (Denmark)
Booss-Bavnbek, Bernhelm
2011-01-01
This paper applies I.M. Gelfand's distinction between adequate and non-adequate use of mathematical language in different contexts to the newly opened window of model-based measurements of intracellular dynamics. The specifics of geometry and dynamics on the mesoscale of cell physiology are elabo...
Diophantine geometry an introduction
Hindry, Marc
2000-01-01
This is an introduction to diophantine geometry at the advanced graduate level. The book contains a proof of the Mordell conjecture which will make it quite attractive to graduate students and professional mathematicians. In each part of the book, the reader will find numerous exercises.
Sliding vane geometry turbines
Sun, Harold Huimin; Zhang, Jizhong; Hu, Liangjun; Hanna, Dave R
2014-12-30
Various systems and methods are described for a variable geometry turbine. In one example, a turbine nozzle comprises a central axis and a nozzle vane. The nozzle vane includes a stationary vane and a sliding vane. The sliding vane is positioned to slide in a direction substantially tangent to an inner circumference of the turbine nozzle and in contact with the stationary vane.
Boyer, Carl B
2012-01-01
Designed as an integrated survey of the development of analytic geometry, this study presents the concepts and contributions from before the Alexandrian Age through the eras of the great French mathematicians Fermat and Descartes, and on through Newton and Euler to the "Golden Age," from 1789 to 1850.
Coxeter, HSM
1965-01-01
This textbook introduces non-Euclidean geometry, and the third edition adds a new chapter, including a description of the two families of 'mid-lines' between two given lines and an elementary derivation of the basic formulae of spherical trigonometry and hyperbolic trigonometry, and other new material.
International Nuclear Information System (INIS)
Ezin, J.P.
1988-08-01
The lectures given at the ''5th Symposium of Mathematics in Abidjan: Differential Geometry and Mechanics'' are presented. They are divided into four chapters: Riemannian metric on a differential manifold, curvature tensor fields on a Riemannian manifold, some classical functionals on Riemannian manifolds and questions. 11 refs
Hartshorne, Robin
2000-01-01
In recent years, I have been teaching a junior-senior-level course on the classi cal geometries. This book has grown out of that teaching experience. I assume only high-school geometry and some abstract algebra. The course begins in Chapter 1 with a critical examination of Euclid's Elements. Students are expected to read concurrently Books I-IV of Euclid's text, which must be obtained sepa rately. The remainder of the book is an exploration of questions that arise natu rally from this reading, together with their modern answers. To shore up the foundations we use Hilbert's axioms. The Cartesian plane over a field provides an analytic model of the theory, and conversely, we see that one can introduce coordinates into an abstract geometry. The theory of area is analyzed by cutting figures into triangles. The algebra of field extensions provides a method for deciding which geometrical constructions are possible. The investigation of the parallel postulate leads to the various non-Euclidean geometries. And ...
Sastre Toraño, J; van Hattum, S H
2001-10-01
A new method is presented for the quantitative analysis of compounds in pharmaceutical preparations Fourier transform (FT) mid-infrared (MIR) spectroscopy with an attenuated total reflection (ATR) module. Reduction of the quantity of overlapping absorption bands, by interaction of the compound of interest with an appropriate solvent, and the employment of an internal standard (IS), makes MIR suitable for quantitative analysis. Vigabatrin, as active compound in vigabatrin 100-mg capsules, was used as a model compound for the development of the method. Vigabatrin was extracted from the capsule content with water after addition of a sodium thiosulfate IS solution. The extract was concentrated by volume reduction and applied to the FTMIR-ATR module. Concentrations of unknown samples were calculated from the ratio of the vigabatrin band area (1321-1610 cm(-1)) and the IS band area (883-1215 cm(-1)) using a calibration standard. The ratio of the area of the vigabatrin peak to that of the IS was linear with the concentration in the range of interest (90-110 mg, in twofold; n=2). The accuracy of the method in this range was 99.7-100.5% (n=5) with a variability of 0.4-1.3% (n=5). The comparison of the presented method with an HPLC assay showed similar results; the analysis of five vigabatrin 100-mg capsules resulted in a mean concentration of 102 mg with a variation of 2% with both methods.
The Reflective Learning Continuum: Reflecting on Reflection
Peltier, James W.; Hay, Amanda; Drago, William
2005-01-01
The importance of reflection to marketing educators is increasingly recognized. However, there is a lack of empirical research that considers reflection within the context of both the marketing and general business education literature. This article describes the use of an instrument that can be used to measure four identified levels of a…
Multivariate calculus and geometry
Dineen, Seán
2014-01-01
Multivariate calculus can be understood best by combining geometric insight, intuitive arguments, detailed explanations and mathematical reasoning. This textbook has successfully followed this programme. It additionally provides a solid description of the basic concepts, via familiar examples, which are then tested in technically demanding situations. In this new edition the introductory chapter and two of the chapters on the geometry of surfaces have been revised. Some exercises have been replaced and others provided with expanded solutions. Familiarity with partial derivatives and a course in linear algebra are essential prerequisites for readers of this book. Multivariate Calculus and Geometry is aimed primarily at higher level undergraduates in the mathematical sciences. The inclusion of many practical examples involving problems of several variables will appeal to mathematics, science and engineering students.
Multilevel geometry optimization
Rodgers, Jocelyn M.; Fast, Patton L.; Truhlar, Donald G.
2000-02-01
Geometry optimization has been carried out for three test molecules using six multilevel electronic structure methods, in particular Gaussian-2, Gaussian-3, multicoefficient G2, multicoefficient G3, and two multicoefficient correlation methods based on correlation-consistent basis sets. In the Gaussian-2 and Gaussian-3 methods, various levels are added and subtracted with unit coefficients, whereas the multicoefficient Gaussian-x methods involve noninteger parameters as coefficients. The multilevel optimizations drop the average error in the geometry (averaged over the 18 cases) by a factor of about two when compared to the single most expensive component of a given multilevel calculation, and in all 18 cases the accuracy of the atomization energy for the three test molecules improves; with an average improvement of 16.7 kcal/mol.
Multilevel geometry optimization
Energy Technology Data Exchange (ETDEWEB)
Rodgers, Jocelyn M. [Department of Chemistry and Supercomputer Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431 (United States); Fast, Patton L. [Department of Chemistry and Supercomputer Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431 (United States); Truhlar, Donald G. [Department of Chemistry and Supercomputer Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431 (United States)
2000-02-15
Geometry optimization has been carried out for three test molecules using six multilevel electronic structure methods, in particular Gaussian-2, Gaussian-3, multicoefficient G2, multicoefficient G3, and two multicoefficient correlation methods based on correlation-consistent basis sets. In the Gaussian-2 and Gaussian-3 methods, various levels are added and subtracted with unit coefficients, whereas the multicoefficient Gaussian-x methods involve noninteger parameters as coefficients. The multilevel optimizations drop the average error in the geometry (averaged over the 18 cases) by a factor of about two when compared to the single most expensive component of a given multilevel calculation, and in all 18 cases the accuracy of the atomization energy for the three test molecules improves; with an average improvement of 16.7 kcal/mol. (c) 2000 American Institute of Physics.
Krauss, Lawrence M.; Turner, Michael S.
1999-01-01
The recognition that the cosmological constant may be non-zero forces us to re-evaluate standard notions about the connection between geometry and the fate of our Universe. An open Universe can recollapse, and a closed Universe can expand forever. As a corollary, we point out that there is no set of cosmological observations we can perform that will unambiguously allow us to determine what the ultimate destiny of the Universe will be.
DEFF Research Database (Denmark)
Tamke, Martin; Ramsgaard Thomsen, Mette; Riiber Nielsen, Jacob
2009-01-01
The versatility of wood constructions and traditional wood joints for the production of non standard elements was in focus of a design based research. Herein we established a seamless process from digital design to fabrication. A first research phase centered on the development of a robust...... parametric model and a generic design language a later explored the possibilities to construct complex shaped geometries with self registering joints on modern wood crafting machines. The research was carried out as collaboration with industrial partners....
International Nuclear Information System (INIS)
Lepora, N.; Kibble, T.
1999-01-01
We analyse symmetry breaking in the Weinberg-Salam model paying particular attention to the underlying geometry of the theory. In this context we find two natural metrics upon the vacuum manifold: an isotropic metric associated with the scalar sector, and a squashed metric associated with the gauge sector. Physically, the interplay between these metrics gives rise to many of the non-perturbative features of Weinberg-Salam theory. (author)
International Nuclear Information System (INIS)
Hull, C.M.
1993-01-01
The geometric structure of theories with gauge fields of spins two and higher should involve a higher spin generalisation of Riemannian geometry. Such geometries are discussed and the case of W ∝ -gravity is analysed in detail. While the gauge group for gravity in d dimensions is the diffeomorphism group of the space-time, the gauge group for a certain W-gravity theory (which is W ∝ -gravity in the case d=2) is the group of symplectic diffeomorphisms of the cotangent bundle of the space-time. Gauge transformations for W-gravity gauge fields are given by requiring the invariance of a generalised line element. Densities exist and can be constructed from the line element (generalising √detg μν ) only if d=1 or d=2, so that only for d=1,2 can actions be constructed. These two cases and the corresponding W-gravity actions are considered in detail. In d=2, the gauge group is effectively only a subgroup of the symplectic diffeomorphisms group. Some of the constraints that arise for d=2 are similar to equations arising in the study of self-dual four-dimensional geometries and can be analysed using twistor methods, allowing contact to be made with other formulations of W-gravity. While the twistor transform for self-dual spaces with one Killing vector reduces to a Legendre transform, that for two Killing vectors gives a generalisation of the Legendre transform. (orig.)
Integral geometry and valuations
Solanes, Gil
2014-01-01
Valuations are finitely additive functionals on the space of convex bodies. Their study has become a central subject in convexity theory, with fundamental applications to integral geometry. In the last years there has been significant progress in the theory of valuations, which in turn has led to important achievements in integral geometry. This book originated from two courses delivered by the authors at the CRM and provides a self-contained introduction to these topics, covering most of the recent advances. The first part, by Semyon Alesker, is devoted to the theory of convex valuations, with emphasis on the latest developments. A special focus is put on the new fundamental structures of the space of valuations discovered after Alesker's irreducibility theorem. Moreover, the author describes the newly developed theory of valuations on manifolds. In the second part, Joseph H. G. Fu gives a modern introduction to integral geometry in the sense of Blaschke and Santaló, based on the notions and tools presented...
CBM RICH geometry optimization
Energy Technology Data Exchange (ETDEWEB)
Mahmoud, Tariq; Hoehne, Claudia [II. Physikalisches Institut, Giessen Univ. (Germany); Collaboration: CBM-Collaboration
2016-07-01
The Compressed Baryonic Matter (CBM) experiment at the future FAIR complex will investigate the phase diagram of strongly interacting matter at high baryon density and moderate temperatures in A+A collisions from 2-11 AGeV (SIS100) beam energy. The main electron identification detector in the CBM experiment will be a RICH detector with a CO{sub 2} gaseous-radiator, focusing spherical glass mirrors, and MAPMT photo-detectors being placed on a PMT-plane. The RICH detector is located directly behind the CBM dipole magnet. As the final magnet geometry is now available, some changes in the RICH geometry become necessary. In order to guarantee a magnetic field of 1 mT at maximum in the PMT plane for effective operation of the MAPMTs, two measures have to be taken: The PMT plane is moved outwards of the stray field by tilting the mirrors by 10 degrees and shielding boxes have been designed. In this contribution the results of the geometry optimization procedure are presented.
Introducing geometry concept based on history of Islamic geometry
Maarif, S.; Wahyudin; Raditya, A.; Perbowo, K. S.
2018-01-01
Geometry is one of the areas of mathematics interesting to discuss. Geometry also has a long history in mathematical developments. Therefore, it is important integrated historical development of geometry in the classroom to increase’ knowledge of how mathematicians earlier finding and constructing a geometric concept. Introduction geometrical concept can be started by introducing the Muslim mathematician who invented these concepts so that students can understand in detail how a concept of geometry can be found. However, the history of mathematics development, especially history of Islamic geometry today is less popular in the world of education in Indonesia. There are several concepts discovered by Muslim mathematicians that should be appreciated by the students in learning geometry. Great ideas of mathematicians Muslim can be used as study materials to supplement religious character values taught by Muslim mathematicians. Additionally, by integrating the history of geometry in teaching geometry are expected to improve motivation and geometrical understanding concept.
Directory of Open Access Journals (Sweden)
Giorgina B Piccoli
2018-03-01
Full Text Available Chronic Kidney Disease affects approximately 10% of the world’s adult population: it is within the top 20 causes of death worldwide, and its impact on patients and their families can be devastating. World Kidney Day and International Women’s Day in 2018 coincide, thus offering an opportunity to reflect on the importance of women’s health and specifically their kidney health, on the community, and the next generations, as well as to strive to be more curious about the unique aspects of kidney disease in women so that we may apply those learnings more broadly. Girls and women, who make up approximately 50% of the world’s population, are important contributors to society and their families. Gender differences continue to exist around the world in access to education, medical care, and participation in clinical studies. Pregnancy is a unique state for women, offering an opportunity for diagnosis of kidney disease, but also a state where acute and chronic kidney diseases may manifest, and which may impact future generations with respect to kidney health. There are various autoimmune and other conditions that are more likely to impact women with profound consequences for child bearing, and on the fetus. Women have different complications on dialysis than men, and are more likely to be donors than recipients of kidney transplants. In this editorial, we focus on what we do and do not know about women, kidney health, and kidney disease, and what we might learn in the future to improve outcomes worldwide
Directory of Open Access Journals (Sweden)
Giorgina B. Piccoli
2018-03-01
Full Text Available Chronic kidney disease affects approximately 10% of the world's adult population: it is within the top 20 causes of death worldwide, and its impact on patients and their families can be devastating. World Kidney Day and International Women's Day in 2018 coincide, thus offering an opportunity to reflect on the importance of women's health and specifically their kidney health, on the community, and the next generations, as well as to strive to be more curious about the unique aspects of kidney disease in women so that we may apply those learnings more broadly.Girls and women, who make up approximately 50% of the world's population, are important contributors to society and their families. Gender differences continue to exist around the world in access to education, medical care, and participation in clinical studies. Pregnancy is a unique state for women, offering an opportunity for diagnosis of kidney disease, but also a state where acute and chronic kidney diseases may manifest, and which may impact future generations with respect to kidney health. There are various autoimmune and other conditions that are more likely to impact women with profound consequences for child bearing, and on the fetus. Women have different complications on dialysis than men, and are more likely to be donors than recipients of kidney transplants.In this editorial, we focus on what we do and do not know about women, kidney health, and kidney disease, and what we might learn in the future to improve outcomes worldwide. Keywords: Women, Access to care, Kidney health, Acute and chronic kidney disease, Inequities
Conference on Strings, Duality, and Geometry
Phong, Duong; Yau, Shing-Tung; Mirror Symmetry IV
2002-01-01
This book presents contributions of participants of a workshop held at the Centre de Recherches Mathématiques (CRM), University of Montréal. It can be viewed as a sequel to Mirror Symmetry I (1998), Mirror Symmetry II (1996), and Mirror Symmetry III (1999), copublished by the AMS and International Press. The volume presents a broad survey of many of the noteworthy developments that have taken place in string theory, geometry, and duality since the mid 1990s. Some of the topics emphasized include the following: Integrable models and supersymmetric gauge theories; theory of M- and D-branes and noncommutative geometry; duality between strings and gauge theories; and elliptic genera and automorphic forms. Several introductory articles present an overview of the geometric and physical aspects of mirror symmetry and of corresponding developments in symplectic geometry. The book provides an efficient way for a very broad audience of mathematicians and physicists to explore the frontiers of research into this rapi...
Two lectures on D-geometry and noncommutative geometry
International Nuclear Information System (INIS)
Douglas, M.R.
1999-01-01
This is a write-up of lectures given at the 1998 Spring School at the Abdus Salam ICTP. We give a conceptual introduction to D-geometry, the study of geometry as seen by D-branes in string theory, and to noncommutative geometry as it has appeared in D-brane and Matrix theory physics. (author)
Energy Technology Data Exchange (ETDEWEB)
Lentine, Anthony L.; Nielson, Gregory N.; Cruz-Campa, Jose Luis; Okandan, Murat; Goeke, Ronald S.
2018-03-06
A photovoltaic module includes colorized reflective photovoltaic cells that act as pixels. The colorized reflective photovoltaic cells are arranged so that reflections from the photovoltaic cells or pixels visually combine into an image on the photovoltaic module. The colorized photovoltaic cell or pixel is composed of a set of 100 to 256 base color sub-pixel reflective segments or sub-pixels. The color of each pixel is determined by the combination of base color sub-pixels forming the pixel. As a result, each pixel can have a wide variety of colors using a set of base colors, which are created, from sub-pixel reflective segments having standard film thicknesses.
International Nuclear Information System (INIS)
Anon.
1997-01-01
This rubric reports on 10 short notes about international economical facts about nuclear power: Electricite de France (EdF) and its assistance and management contracts with Eastern Europe countries (Poland, Hungary, Bulgaria); Transnuclear Inc. company (a 100% Cogema daughter company) acquired the US Vectra Technologies company; the construction of the Khumo nuclear power plant in Northern Korea plays in favour of the reconciliation between Northern and Southern Korea; the delivery of two VVER 1000 Russian reactors to China; the enforcement of the cooperation agreement between Euratom and Argentina; Japan requested for the financing of a Russian fast breeder reactor; Russia has planned to sell a floating barge-type nuclear power plant to Indonesia; the control of the Swedish reactor vessels of Sydkraft AB company committed to Tractebel (Belgium); the renewal of the nuclear cooperation agreement between Swiss and USA; the call for bids from the Turkish TEAS electric power company for the building of the Akkuyu nuclear power plant answered by three candidates: Atomic Energy of Canada Limited (AECL), Westinghouse (US) and the French-German NPI company. (J.S.)
Seismic reflection imaging, accounting for primary and multiple reflections
Wapenaar, Kees; van der Neut, Joost; Thorbecke, Jan; Broggini, Filippo; Slob, Evert; Snieder, Roel
2015-04-01
Imaging of seismic reflection data is usually based on the assumption that the seismic response consists of primary reflections only. Multiple reflections, i.e. waves that have reflected more than once, are treated as primaries and are imaged at wrong positions. There are two classes of multiple reflections, which we will call surface-related multiples and internal multiples. Surface-related multiples are those multiples that contain at least one reflection at the earth's surface, whereas internal multiples consist of waves that have reflected only at subsurface interfaces. Surface-related multiples are the strongest, but also relatively easy to deal with because the reflecting boundary (the earth's surface) is known. Internal multiples constitute a much more difficult problem for seismic imaging, because the positions and properties of the reflecting interfaces are not known. We are developing reflection imaging methodology which deals with internal multiples. Starting with the Marchenko equation for 1D inverse scattering problems, we derived 3D Marchenko-type equations, which relate reflection data at the surface to Green's functions between virtual sources anywhere in the subsurface and receivers at the surface. Based on these equations, we derived an iterative scheme by which these Green's functions can be retrieved from the reflection data at the surface. This iterative scheme requires an estimate of the direct wave of the Green's functions in a background medium. Note that this is precisely the same information that is also required by standard reflection imaging schemes. However, unlike in standard imaging, our iterative Marchenko scheme retrieves the multiple reflections of the Green's functions from the reflection data at the surface. For this, no knowledge of the positions and properties of the reflecting interfaces is required. Once the full Green's functions are retrieved, reflection imaging can be carried out by which the primaries and multiples are
International Nuclear Information System (INIS)
Hook, D W
2008-01-01
A geometric framework for quantum mechanics arose during the mid 1970s when authors such as Cantoni explored the notion of generalized transition probabilities, and Kibble promoted the idea that the space of pure quantum states provides a natural quantum mechanical analogue for classical phase space. This central idea can be seen easily since the projection of Schroedinger's equation from a Hilbert space into the space of pure spaces is a set of Hamilton's equations. Over the intervening years considerable work has been carried out by a variety of authors and a mature description of quantum mechanics in geometric terms has emerged with many applications. This current offering would seem ideally placed to review the last thirty years of progress and relate this to the most recent work in quantum entanglement. Bengtsson and Zyczkowski's beautifully illustrated volume, Geometry of Quantum States (referred to as GQS from now on) attempts to cover considerable ground in its 466 pages. Its topics range from colour theory in Chapter 1 to quantum entanglement in Chapter 15-to say that this is a whirlwind tour is, perhaps, no understatement. The use of the work 'introduction' in the subtitle of GQS, might suggest to the reader that this work be viewed as a textbook and I think that this interpretation would be incorrect. The authors have chosen to present a survey of different topics with the specific aim to introduce entanglement in geometric terms-the book is not intended as a pedagogical introduction to the geometric approach to quantum mechanics. Each of the fifteen chapters is a short, and mostly self-contained, essay on a particular aspect or application of geometry in the context of quantum mechanics with entanglement being addressed specifically in the final chapter. The chapters fall into three classifications: those concerned with the mathematical background, those which discuss quantum theory and the foundational aspects of the geometric framework, and
Functional integration over geometries
International Nuclear Information System (INIS)
Mottola, E.
1995-01-01
The geometric construction of the functional integral over coset spaces M/G is reviewed. The inner product on the cotangent space of infinitesimal deformations of M defines an invariant distance and volume form, or functional integration measure on the full configuration space. Then, by a simple change of coordinates parameterizing the gauge fiber G, the functional measure on the coset space M/G is deduced. This change of integration variables leads to a Jacobian which is entirely equivalent to the Faddeev--Popov determinant of the more traditional gauge fixed approach in non-abelian gauge theory. If the general construction is applied to the case where G is the group of coordinate reparameterizations of spacetime, the continuum functional integral over geometries, i.e. metrics modulo coordinate reparameterizations may be defined. The invariant functional integration measure is used to derive the trace anomaly and effective action for the conformal part of the metric in two and four dimensional spacetime. In two dimensions this approach generates the Polyakov--Liouville action of closed bosonic non-critical string theory. In four dimensions the corresponding effective action leads to novel conclusions on the importance of quantum effects in gravity in the far infrared, and in particular, a dramatic modification of the classical Einstein theory at cosmological distance scales, signaled first by the quantum instability of classical de Sitter spacetime. Finite volume scaling relations for the functional integral of quantum gravity in two and four dimensions are derived, and comparison with the discretized dynamical triangulation approach to the integration over geometries are discussed. Outstanding unsolved problems in both the continuum definition and the simplicial approach to the functional integral over geometries are highlighted
Dooner, David B
2012-01-01
Building on the first edition published in 1995 this new edition of Kinematic Geometry of Gearing has been extensively revised and updated with new and original material. This includes the methodology for general tooth forms, radius of torsure', cylinder of osculation, and cylindroid of torsure; the author has also completely reworked the '3 laws of gearing', the first law re-written to better parallel the existing 'Law of Gearing" as pioneered by Leonard Euler, expanded from Euler's original law to encompass non-circular gears and hypoid gears, the 2nd law of gearing describing a unique relat
Flegg, H Graham
2001-01-01
This excellent introduction to topology eases first-year math students and general readers into the subject by surveying its concepts in a descriptive and intuitive way, attempting to build a bridge from the familiar concepts of geometry to the formalized study of topology. The first three chapters focus on congruence classes defined by transformations in real Euclidean space. As the number of permitted transformations increases, these classes become larger, and their common topological properties become intuitively clear. Chapters 4-12 give a largely intuitive presentation of selected topics.
Torsional heterotic geometries
International Nuclear Information System (INIS)
Becker, Katrin; Sethi, Savdeep
2009-01-01
We construct new examples of torsional heterotic backgrounds using duality with orientifold flux compactifications. We explain how duality provides a perturbative solution to the type I/heterotic string Bianchi identity. The choice of connection used in the Bianchi identity plays an important role in the construction. We propose the existence of a much larger landscape of compact torsional geometries using string duality. Finally, we present some quantum exact metrics that correspond to NS5-branes placed on an elliptic space. These metrics describe how torus isometries are broken by NS flux.
Geometrie verstehen: statisch - kinematisch
Kroll, Ekkehard
Dem Allgemeinen steht begrifflich das Besondere gegenüber. In diesem Sinne sind allgemeine Überlegungen zum Verstehen von Mathematik zu ergänzen durch Untersuchungen hinsichtlich des Verstehens der einzelnen mathematischen Disziplinen, insbesondere der Geometrie. Hier haben viele Schülerinnen und Schüler Probleme. Diese rühren hauptsächlich daher, dass eine fertige geometrische Konstruktion in ihrer statischen Präsentation auf Papier nicht mehr die einzelnen Konstruktionsschritte erkennen lässt; zum Nachvollzug müssen sie daher ergänzend in einer Konstruktionsbeschreibung festgehalten werden.
Kendig, Keith
2015-01-01
Designed to make learning introductory algebraic geometry as easy as possible, this text is intended for advanced undergraduates and graduate students who have taken a one-year course in algebra and are familiar with complex analysis. This newly updated second edition enhances the original treatment's extensive use of concrete examples and exercises with numerous figures that have been specially redrawn in Adobe Illustrator. An introductory chapter that focuses on examples of curves is followed by a more rigorous and careful look at plane curves. Subsequent chapters explore commutative ring th
Abhyankar, Shreeram Shankar
1964-01-01
This book provides, for use in a graduate course or for self-study by graduate students, a well-motivated treatment of several topics, especially the following: (1) algebraic treatment of several complex variables; (2) geometric approach to algebraic geometry via analytic sets; (3) survey of local algebra; (4) survey of sheaf theory. The book has been written in the spirit of Weierstrass. Power series play the dominant role. The treatment, being algebraic, is not restricted to complex numbers, but remains valid over any complete-valued field. This makes it applicable to situations arising from
Akopyan, A V
2007-01-01
The book is devoted to the properties of conics (plane curves of second degree) that can be formulated and proved using only elementary geometry. Starting with the well-known optical properties of conics, the authors move to less trivial results, both classical and contemporary. In particular, the chapter on projective properties of conics contains a detailed analysis of the polar correspondence, pencils of conics, and the Poncelet theorem. In the chapter on metric properties of conics the authors discuss, in particular, inscribed conics, normals to conics, and the Poncelet theorem for confoca
2015-01-01
This stimulating volume offers a broad collection of the principles of geometry and trigonometry and contains colorful diagrams to bring mathematical principles to life. Subjects are enriched by references to famous mathematicians and their ideas, and the stories are presented in a very comprehensible way. Readers investigate the relationships of points, lines, surfaces, and solids. They study construction methods for drawing figures, a wealth of facts about these figures, and above all, methods to prove the facts. They learn about triangle measure for circular motion, sine and cosine, tangent
REA, The Editors of
2012-01-01
REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Geometry I includes methods of proof, points, lines, planes, angles, congruent angles and line segments, triangles, parallelism, quadrilaterals, geometric inequalities, and geometric
Graded geometry and Poisson reduction
Cattaneo, A S; Zambon, M
2009-01-01
The main result of [2] extends the Marsden-Ratiu reduction theorem [4] in Poisson geometry, and is proven by means of graded geometry. In this note we provide the background material about graded geometry necessary for the proof in [2]. Further, we provide an alternative algebraic proof for the main result. ©2009 American Institute of Physics
Bertelli, Marco O.; Munir, Kerim; Harris, James; Salvador-Carulla, Luis
2016-01-01
Purpose The debate as to whether intellectual disability (ID) should be conceptualized as a health condition or as a disability has intensified as the revision of World Health Organization’s (WHO’s) International Classification of Diseases (ICD) is being finalized. Defining ID as a health condition is central to retaining it in ICD, with significant implications for health policy and access to health services. The purpose of this paper is to include some reflections on the consensus document produced by the first WHO Working Group on the Classification of MR (WHO WG-MR) and on the process that was followed to realize it. The consensus report was the basis for the development of official recommendations sent to the WHO Advisory Group for ICD-11. Design/methodology/approach A mixed qualitative approach was followed in a series of meetings leading to the final consensus report submitted to the WHO Advisory group. These recommendations combined prior expert knowledge with available evidence; a nominal approach was followed throughout with face-to-face conferences. Findings The WG recommended a synonym set (“synset”) ontological approach to the conceptualisation of this health condition underlying a clinical rationale for its diagnosis. It proposed replacing MR with Intellectual Developmental Disorders (IDD) in ICD-11, defined as “a group of developmental conditions characterized by a significant impairment of cognitive functions, which are associated with limitations of learning, adaptive behaviour and skills”. The WG further advised that IDD be included under the parent category of neurodevelopmental disorders, that current distinctions (mild, moderate, severe and profound) be continued as severity qualifiers, and that problem behaviours removed from its core classification structure and instead described as associated features. Originality/value Within the ID/IDD synset two different names combine distinct aspects under a single construct that describes
Students’ Errors in Geometry Viewed from Spatial Intelligence
Riastuti, N.; Mardiyana, M.; Pramudya, I.
2017-09-01
Geometry is one of the difficult materials because students must have ability to visualize, describe images, draw shapes, and know the kind of shapes. This study aim is to describe student error based on Newmans’ Error Analysis in solving geometry problems viewed from spatial intelligence. This research uses descriptive qualitative method by using purposive sampling technique. The datas in this research are the result of geometri material test and interview by the 8th graders of Junior High School in Indonesia. The results of this study show that in each category of spatial intelligence has a different type of error in solving the problem on the material geometry. Errors are mostly made by students with low spatial intelligence because they have deficiencies in visual abilities. Analysis of student error viewed from spatial intelligence is expected to help students do reflection in solving the problem of geometry.
Reflection: A Socratic approach.
Van Seggelen-Damen, Inge C M; Van Hezewijk, René; Helsdingen, Anne S; Wopereis, Iwan G J H
2017-12-01
Reflection is a fuzzy concept. In this article we reveal the paradoxes involved in studying the nature of reflection. Whereas some scholars emphasize its discursive nature, we go further and underline its resemblance to the self-biased dialogue Socrates had with the slave in Plato's Meno . The individual and internal nature of the reflection process creates difficulty for studying it validly and reliably. We focus on methodological issues and use Hans Linschoten's view of coupled systems to identify, analyze, and interpret empirical research on reflection. We argue that researchers and research participants can take on roles in several possible system couplings. Depending on who controls the manipulation of the stimulus, who controls the measuring instrument, who interprets the measurement and the response, different types of research questions can be answered. We conclude that reflection may be validly studied by combining different couplings of experimenter, manipulation, stimulus, participant, measurement, and response.
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education. Personal Reflections. Articles in Resonance – Journal of Science Education. Volume 6 Issue 3 March 2001 pp 90-93 Personal Reflections. Why did I opt for Career in Science? Jayant V Narlikar · More Details Fulltext PDF. Volume 9 Issue 8 August 2004 pp 89-89 ...
International Nuclear Information System (INIS)
Eggermont, G.
2006-01-01
In 2005, PISA organised proactive meetings of reflection groups on involvement in decision making, expert culture and ethical aspects of radiation protection.All reflection group meetings address particular targeted audiences while the output publication in book form is put forward
DEFF Research Database (Denmark)
Boura, Christina; Canteaut, Anne; Knudsen, Lars Ramkilde
2017-01-01
study the necessary properties for this coupling permutation. Special care has to be taken of some related-key distinguishers since, in the context of reflection ciphers, they may provide attacks in the single-key setting.We then derive some criteria for constructing secure reflection ciphers...
Bochnak, Jacek; Roy, Marie-Françoise
1998-01-01
This book is a systematic treatment of real algebraic geometry, a subject that has strong interrelation with other areas of mathematics: singularity theory, differential topology, quadratic forms, commutative algebra, model theory, complexity theory etc. The careful and clearly written account covers both basic concepts and up-to-date research topics. It may be used as text for a graduate course. The present edition is a substantially revised and expanded English version of the book "Géometrie algébrique réelle" originally published in French, in 1987, as Volume 12 of ERGEBNISSE. Since the publication of the French version the theory has made advances in several directions. Many of these are included in this English version. Thus the English book may be regarded as a completely new treatment of the subject.
Critique of information geometry
International Nuclear Information System (INIS)
Skilling, John
2014-01-01
As applied to probability, information geometry fails because probability distributions do not form a metric space. Probability theory rests on a compelling foundation of elementary symmetries, which also support information (aka minus entropy, Kullback-Leibler) H(p;q) as the unique measure of divergence from source probability distribution q to destination p. Because the only compatible connective H is from≠to asymmetric, H(p;q)≠H(q;p), there can be no compatible geometrical distance (which would necessarily be from=to symmetric). Hence there is no distance relationship compatible with the structure of probability theory. Metrics g and densities sqrt(det(g)) interpreted as prior probabilities follow from the definition of distance, and must fail likewise. Various metrics and corresponding priors have been proposed, Fisher's being the most popular, but all must behave unacceptably. This is illustrated with simple counter-examples
International Nuclear Information System (INIS)
Correa, Diego H.; Silva, Guillermo A.
2008-01-01
We discuss how geometrical and topological aspects of certain (1/2)-BPS type IIB geometries are captured by their dual operators in N = 4 Super Yang-Mills theory. The type IIB solutions are characterized by arbitrary droplet pictures in a plane and we consider, in particular, axially symmetric droplets. The 1-loop anomalous dimension of the dual gauge theory operators probed with single traces is described by some bosonic lattice Hamiltonians. These Hamiltonians are shown to encode the topology of the droplets. In appropriate BMN limits, the Hamiltonians spectrum reproduces the spectrum of near-BPS string excitations propagating along each of the individual edges of the droplet. We also study semiclassical regimes for the Hamiltonians. For droplets having disconnected constituents, the Hamiltonian admits different complimentary semiclassical descriptions, each one replicating the semiclassical description for closed strings extending in each of the constituents
Emergent geometry of membranes
Energy Technology Data Exchange (ETDEWEB)
Badyn, Mathias Hudoba de; Karczmarek, Joanna L.; Sabella-Garnier, Philippe; Yeh, Ken Huai-Che [Department of Physics and Astronomy, University of British Columbia,6224 Agricultural Road, Vancouver (Canada)
2015-11-13
In work http://dx.doi.org/10.1103/PhysRevD.86.086001, a surface embedded in flat ℝ{sup 3} is associated to any three hermitian matrices. We study this emergent surface when the matrices are large, by constructing coherent states corresponding to points in the emergent geometry. We find the original matrices determine not only shape of the emergent surface, but also a unique Poisson structure. We prove that commutators of matrix operators correspond to Poisson brackets. Through our construction, we can realize arbitrary noncommutative membranes: for example, we examine a round sphere with a non-spherically symmetric Poisson structure. We also give a natural construction for a noncommutative torus embedded in ℝ{sup 3}. Finally, we make remarks about area and find matrix equations for minimal area surfaces.
DEFF Research Database (Denmark)
Alcock, Gordon Lindsay
2013-01-01
´ These are all based on Blooms taxonomy and levels of competence and form a major part of individual student and group learning portfolios. Key Words :Project-Based learning, Reflective Portfolios, Self assessment, Defining learning gains, Developing learning strategies , Reflections on and for learning....... It contrasts the students’ self-assessment in a range of ‘product’ skills such as Revit, Structural Design, Mathematics of construction, Technical Installations; as well as ‘process’ competencies such as ‘Working in a team’, Sharing knowledge, Maintaining a portfolio and Reflecting ON learning and FOR learning......This paper documents 1st semester student reflections on “learning to learn” in a team-based PBL environment with quantitative and qualitative student reflective feedback on the learning gains of 60 Architectural Technology and Construction Management students at VIA University College, Denmark...
Computational commutative and non-commutative algebraic geometry
Cojocaru, S; Ufnarovski, V
2005-01-01
This publication gives a good insight in the interplay between commutative and non-commutative algebraic geometry. The theoretical and computational aspects are the central theme in this study. The topic is looked at from different perspectives in over 20 lecture reports. It emphasizes the current trends in commutative and non-commutative algebraic geometry and algebra. The contributors to this publication present the most recent and state-of-the-art progresses which reflect the topic discussed in this publication. Both researchers and graduate students will find this book a good source of information on commutative and non-commutative algebraic geometry.
Geometry through history Euclidean, hyperbolic, and projective geometries
Dillon, Meighan I
2018-01-01
Presented as an engaging discourse, this textbook invites readers to delve into the historical origins and uses of geometry. The narrative traces the influence of Euclid’s system of geometry, as developed in his classic text The Elements, through the Arabic period, the modern era in the West, and up to twentieth century mathematics. Axioms and proof methods used by mathematicians from those periods are explored alongside the problems in Euclidean geometry that lead to their work. Students cultivate skills applicable to much of modern mathematics through sections that integrate concepts like projective and hyperbolic geometry with representative proof-based exercises. For its sophisticated account of ancient to modern geometries, this text assumes only a year of college mathematics as it builds towards its conclusion with algebraic curves and quaternions. Euclid’s work has affected geometry for thousands of years, so this text has something to offer to anyone who wants to broaden their appreciation for the...
On organizing principles of discrete differential geometry. Geometry of spheres
International Nuclear Information System (INIS)
Bobenko, Alexander I; Suris, Yury B
2007-01-01
Discrete differential geometry aims to develop discrete equivalents of the geometric notions and methods of classical differential geometry. This survey contains a discussion of the following two fundamental discretization principles: the transformation group principle (smooth geometric objects and their discretizations are invariant with respect to the same transformation group) and the consistency principle (discretizations of smooth parametrized geometries can be extended to multidimensional consistent nets). The main concrete geometric problem treated here is discretization of curvature-line parametrized surfaces in Lie geometry. Systematic use of the discretization principles leads to a discretization of curvature-line parametrization which unifies circular and conical nets.
Higher geometry an introduction to advanced methods in analytic geometry
Woods, Frederick S
2005-01-01
For students of mathematics with a sound background in analytic geometry and some knowledge of determinants, this volume has long been among the best available expositions of advanced work on projective and algebraic geometry. Developed from Professor Woods' lectures at the Massachusetts Institute of Technology, it bridges the gap between intermediate studies in the field and highly specialized works.With exceptional thoroughness, it presents the most important general concepts and methods of advanced algebraic geometry (as distinguished from differential geometry). It offers a thorough study
Advanced geometries for ballistic neutron guides
International Nuclear Information System (INIS)
Schanzer, Christian; Boeni, Peter; Filges, Uwe; Hils, Thomas
2004-01-01
Sophisticated neutron guide systems take advantage of supermirrors being used to increase the neutron flux. However, the finite reflectivity of supermirrors becomes a major loss mechanism when many reflections occur, e.g. in long neutron guides and for long wavelengths. In order to reduce the number of reflections, ballistic neutron guides have been proposed. Usually linear tapered sections are used to enlarge the cross-section and finally, focus the beam to the sample. The disadvantages of linear tapering are (i) an inhomogeneous phase space at the sample position and (ii) a decreasing flux with increasing distance from the exit of the guide. We investigate the properties of parabolic and elliptic tapering for ballistic neutron guides, using the Monte Carlo program McStas with a new guide component dedicated for such geometries. We show that the maximum flux can indeed be shifted away from the exit of the guide. In addition we explore the possibilities of parabolic and elliptic geometries to create point like sources for dedicated experimental demands
An introduction to incidence geometry
De Bruyn, Bart
2016-01-01
This book gives an introduction to the field of Incidence Geometry by discussing the basic families of point-line geometries and introducing some of the mathematical techniques that are essential for their study. The families of geometries covered in this book include among others the generalized polygons, near polygons, polar spaces, dual polar spaces and designs. Also the various relationships between these geometries are investigated. Ovals and ovoids of projective spaces are studied and some applications to particular geometries will be given. A separate chapter introduces the necessary mathematical tools and techniques from graph theory. This chapter itself can be regarded as a self-contained introduction to strongly regular and distance-regular graphs. This book is essentially self-contained, only assuming the knowledge of basic notions from (linear) algebra and projective and affine geometry. Almost all theorems are accompanied with proofs and a list of exercises with full solutions is given at the end...
International Nuclear Information System (INIS)
Buescher, R.
2005-01-01
Casimir interactions are interactions induced by quantum vacuum fluctuations and thermal fluctuations of the electromagnetic field. Using a path integral quantization for the gauge field, an effective Gaussian action will be derived which is the starting point to compute Casimir forces between macroscopic objects analytically and numerically. No assumptions about the independence of the material and shape dependent contributions to the interaction are made. We study the limit of flat surfaces in further detail and obtain a concise derivation of Lifshitz' theory of molecular forces. For the case of ideally conducting boundaries, the Gaussian action will be calculated explicitly. Both limiting cases are also discussed within the framework of a scalar field quantization approach, which is applicable for translationally invariant geometries. We develop a non-perturbative approach to calculate the Casimir interaction from the Gaussian action for periodically deformed and ideally conducting objects numerically. The obtained results reveal two different scaling regimes for the Casimir force as a function of the distance between the objects, their deformation wavelength and -amplitude. The results confirm that the interaction is non-additive, especially in the presence of strong geometric deformations. Furthermore, the numerical approach is extended to calculate lateral Casimir forces. The results are consistent with the results of the proximity-force approximation for large deformation wavelengths. A qualitatively different behaviour between the normal and lateral force is revealed. We also establish a relation between the boundary induced change of the of the density of states for the scalar Helmholtz equation and the Casimir interaction using the path integral method. For statically deformed boundaries, this relation can be expressed as a novel trace formula, which is formally similar to the so-called Krein-Friedel-Lloyd formula. While the latter formula describes the
Planetary Image Geometry Library
Deen, Robert C.; Pariser, Oleg
2010-01-01
The Planetary Image Geometry (PIG) library is a multi-mission library used for projecting images (EDRs, or Experiment Data Records) and managing their geometry for in-situ missions. A collection of models describes cameras and their articulation, allowing application programs such as mosaickers, terrain generators, and pointing correction tools to be written in a multi-mission manner, without any knowledge of parameters specific to the supported missions. Camera model objects allow transformation of image coordinates to and from view vectors in XYZ space. Pointing models, specific to each mission, describe how to orient the camera models based on telemetry or other information. Surface models describe the surface in general terms. Coordinate system objects manage the various coordinate systems involved in most missions. File objects manage access to metadata (labels, including telemetry information) in the input EDRs and RDRs (Reduced Data Records). Label models manage metadata information in output files. Site objects keep track of different locations where the spacecraft might be at a given time. Radiometry models allow correction of radiometry for an image. Mission objects contain basic mission parameters. Pointing adjustment ("nav") files allow pointing to be corrected. The object-oriented structure (C++) makes it easy to subclass just the pieces of the library that are truly mission-specific. Typically, this involves just the pointing model and coordinate systems, and parts of the file model. Once the library was developed (initially for Mars Polar Lander, MPL), adding new missions ranged from two days to a few months, resulting in significant cost savings as compared to rewriting all the application programs for each mission. Currently supported missions include Mars Pathfinder (MPF), MPL, Mars Exploration Rover (MER), Phoenix, and Mars Science Lab (MSL). Applications based on this library create the majority of operational image RDRs for those missions. A
Mid infrared upconversion spectroscopy using diffuse reflectance
DEFF Research Database (Denmark)
Sanders, Nicolai Højer; Kehlet, Louis M.; Dam, Jeppe Seidelin
2014-01-01
specifically that upconversion methods can be deployed using a diffuse reflectance setup where the test sample is irradiated by a thermal light source, i.e. a globar. The diffuse reflectance geometry is particularly well suited when a transmission setup cannot be used. This situation may happen for highly...
Initiation to global Finslerian geometry
Akbar-Zadeh, Hassan
2006-01-01
After a brief description of the evolution of thinking on Finslerian geometry starting from Riemann, Finsler, Berwald and Elie Cartan, the book gives a clear and precise treatment of this geometry. The first three chapters develop the basic notions and methods, introduced by the author, to reach the global problems in Finslerian Geometry. The next five chapters are independent of each other, and deal with among others the geometry of generalized Einstein manifolds, the classification of Finslerian manifolds of constant sectional curvatures. They also give a treatment of isometric, affine, p
DEFF Research Database (Denmark)
Burcharth, H. F.; Larsen, Brian Juul
The investigation concerns the design of a new internal breakwater in the main port of Ibiza. The objective of the model tests was in the first hand to optimize the cross section to make the wave reflection low enough to ensure that unacceptable wave agitation will not occur in the port. Secondly...
International Nuclear Information System (INIS)
Eklund, S.; Mandel, H.; Teller, E.
1977-01-01
Personal reflections after twenty one years of nuclear power are presented by a number of those who were international figures in the nuclear energy field during that period. Lessons learnt, achievements, prospects and predictions for the future are discussed in eleven brief surveys. (U.K.)
Directory of Open Access Journals (Sweden)
Šárka Nedomová
2013-01-01
Full Text Available Precise quantification of the profile of egg can provide a powerful tool for the analysis of egg shape for various biological problems. A new approach to the geometry of a Ostrich’s egg profile is presented here using an analysing the egg’s digital photo by edge detection techniques. The obtained points on the eggshell counter are fitted by the Fourier series. The obtained equations describing an egg profile have been used to calculate radii of curvature. The radii of the curvature at the important point of the egg profile (sharp end, blunt end and maximum thickness are independent on the egg shape index. The exact values of the egg surface and the egg volume have been obtained. These quantities are also independent on the egg shape index. These quantities can be successively estimated on the basis of simplified equations which are expressed in terms of the egg length, L¸ and its width, B. The surface area of the eggshells also exhibits good correlation with the egg long circumference length. Some limitations of the most used procedures have been also shown.
Nonperturbative quantum geometries
International Nuclear Information System (INIS)
Jacobson, T.; California Univ., Santa Barbara; Smolin, L.; California Univ., Santa Barbara
1988-01-01
Using the self-dual representation of quantum general relativity, based on Ashtekar's new phase space variables, we present an infinite dimensional family of quantum states of the gravitational field which are exactly annihilated by the hamiltonian constraint. These states are constructed from Wilson loops for Ashtekar's connection (which is the spatial part of the left handed spin connection). We propose a new regularization procedure which allows us to evaluate the action of the hamiltonian constraint on these states. Infinite linear combinations of these states which are formally annihilated by the diffeomorphism constraints as well are also described. These are explicit examples of physical states of the gravitational field - and for the compact case are exact zero eigenstates of the hamiltonian of quantum general relativity. Several different approaches to constructing diffeomorphism invariant states in the self dual representation are also described. The physical interpretation of the states described here is discussed. However, as we do not yet know the physical inner product, any interpretation is at this stage speculative. Nevertheless, this work suggests that quantum geometry at Planck scales might be much simpler when explored in terms of the parallel transport of left-handed spinors than when explored in terms of the three metric. (orig.)
International Nuclear Information System (INIS)
Aspinwall, P.S.; Luetken, C.A.
1991-01-01
We analyze the mirror manifold hypothesis in one and three dimensions using the simplest available representations of the N = 2 superconformal algebra. The symmetries of these tensor models can be divided out to give an explicit representation of the mirror, and we give a simple group theoretical algorithm for determining which symmetries should be used. We show that the mirror of a superconformal field theory does not always have a geometrical interpretation, but when it does, deformations of complex structure of one manifold are reflected in deformations of the Kaehler form of the mirror manifold, and we show how the large radius limit of a manifold corresponds to a large complex structure limit in the mirror manifold. The mirror of the Tian-Yau three generation model is constructed both as a conformal field theory and as an algebraic variety with Euler number six. The Hodge numbers of this manifolds are fixed, but the intersection numbes are highly ambiguous, presumably reflected a rich structure of multicritical points in the moduli space of the field theory. (orig.)
International Nuclear Information System (INIS)
Lucon, Oswaldo; Romeiro, Viviane; Pacca, Sergio
2013-01-01
This short communication presents a synthesis of a Working Group on Carbon Emission Policy and Regulation held at the University of Sao Paulo, in Brazil. The document looked at the problems with the international negotiations, the options for Brazil as it attempts to control emissions, and ways to leverage the mitigation process. Several options are currently being proposed, but these are neither clear in order to support a solid polycentric approach with adequate metrics, nor a robust international coordination and a sound scientific communication. Brazil has a central role in this process, for having successful initiatives on renewable energy and deforestation control. Its leadership can demonstrate how such policies might take shape. However, the country´s future is uncertain in terms of low carbon development. Although the country is still well positioned among BRICS to find practical solutions to the stalemate in international cooperation, several internal challenges need to be harmonized. - Highlights: • The work presents results of a recent climate change mitigation policies workshop. • It assesses Brazil's potential role in shaping future policies and negotiations. • Policies are evaluated based on domestic and international effects. • Suggests how Brazil's national effort could leverage the international processes
Analytic Reflected Lightcurves for Exoplanets
Haggard, Hal M.; Cowan, Nicolas B.
2018-04-01
The disk-integrated reflected brightness of an exoplanet changes as a function of time due to orbital and rotational motion coupled with an inhomogeneous albedo map. We have previously derived analytic reflected lightcurves for spherical harmonic albedo maps in the special case of a synchronously-rotating planet on an edge-on orbit (Cowan, Fuentes & Haggard 2013). In this letter, we present analytic reflected lightcurves for the general case of a planet on an inclined orbit, with arbitrary spin period and non-zero obliquity. We do so for two different albedo basis maps: bright points (δ-maps), and spherical harmonics (Y_l^m-maps). In particular, we use Wigner D-matrices to express an harmonic lightcurve for an arbitrary viewing geometry as a non-linear combination of harmonic lightcurves for the simpler edge-on, synchronously rotating geometry. These solutions will enable future exploration of the degeneracies and information content of reflected lightcurves, as well as fast calculation of lightcurves for mapping exoplanets based on time-resolved photometry. To these ends we make available Exoplanet Analytic Reflected Lightcurves (EARL), a simple open-source code that allows rapid computation of reflected lightcurves.
Geometry of hyperbolic monopoles
International Nuclear Information System (INIS)
Nash, C.
1986-01-01
The hyperbolic monopoles of Atiyah [M. F. Atiyah, Commun. Math. Phys. 93, 471 (1984); ''Magnetic monopoles in hyperbolic space,'' in Proceedings of the International Colloquium on Vector Bundles (Tata Institute, Bombay, 1984)] and Chakrabarti [A. Chakrabarti, J. Math. Phys. 27, 340 (1986)] are introduced and their geometric properties and relations to instantons and ordinary monopoles clarified. A key tool is the use of the ball model of hyperbolic space to construct and examine solutions
GPS: Geometry, Probability, and Statistics
Field, Mike
2012-01-01
It might be said that for most occupations there is now less of a need for mathematics than there was say fifty years ago. But, the author argues, geometry, probability, and statistics constitute essential knowledge for everyone. Maybe not the geometry of Euclid, but certainly geometrical ways of thinking that might enable us to describe the world…
Surrogate Modeling for Geometry Optimization
DEFF Research Database (Denmark)
Rojas Larrazabal, Marielba de la Caridad; Abraham, Yonas; Holzwarth, Natalie
2009-01-01
A new approach for optimizing the nuclear geometry of an atomic system is described. Instead of the original expensive objective function (energy functional), a small number of simpler surrogates is used.......A new approach for optimizing the nuclear geometry of an atomic system is described. Instead of the original expensive objective function (energy functional), a small number of simpler surrogates is used....
Kaehler geometry and SUSY mechanics
International Nuclear Information System (INIS)
Bellucci, Stefano; Nersessian, Armen
2001-01-01
We present two examples of SUSY mechanics related with Kaehler geometry. The first system is the N = 4 supersymmetric one-dimensional sigma-model proposed in hep-th/0101065. Another system is the N = 2 SUSY mechanics whose phase space is the external algebra of an arbitrary Kaehler manifold. The relation of these models with antisymplectic geometry is discussed
A prediction for bubbling geometries
Okuda, Takuya
2007-01-01
We study the supersymmetric circular Wilson loops in N=4 Yang-Mills theory. Their vacuum expectation values are computed in the parameter region that admits smooth bubbling geometry duals. The results are a prediction for the supergravity action evaluated on the bubbling geometries for Wilson loops.
Molecular motion in restricted geometries
Indian Academy of Sciences (India)
Molecular dynamics in restricted geometries is known to exhibit anomalous behaviour. Diffusion, translational or rotational, of molecules is altered significantly on confinement in restricted geometries. Quasielastic neutron scattering (QENS) offers a unique possibility of studying molecular motion in such systems. Both time ...
Conference on Complex Geometry and Mirror Symmetry
Vinet, Luc; Yau, Shing-Tung; Mirror Symmetry III
1999-01-01
This book presents surveys from a workshop held during the theme year in geometry and topology at the Centre de recherches mathématiques (CRM, University of Montréal). The volume is in some sense a sequel to Mirror Symmetry I (1998) and Mirror Symmetry II (1996), copublished by the AMS and International Press. Included are recent developments in the theory of mirror manifolds and the related areas of complex and symplectic geometry. The long introductory articles explain the key physical ideas and motivation, namely conformal field theory, supersymmetry, and string theory. Open problems are emphasized. Thus the book provides an efficient way for a very broad audience of mathematicians and physicists to reach the frontier of research in this fast expanding area. - See more at: http://bookstore.ams.org/amsip-10#sthash.DbxEFJDx.dpuf
Smith, J. A.; Cooper, K.; Randolph, M.
1984-01-01
A classical description of the one dimensional radiative transfer treatment of vegetation canopies was completed and the results were tested against measured prairie (blue grama) and agricultural canopies (soybean). Phase functions are calculated in terms of directly measurable biophysical characteristics of the canopy medium. While the phase functions tend to exhibit backscattering anisotropy, their exact behavior is somewhat more complex and wavelength dependent. A Monte Carlo model was developed that treats soil surfaces with large periodic variations in three dimensions. A photon-ray tracing technology is used. Currently, the rough soil surface is described by analytic functions and appropriate geometric calculations performed. A bidirectional reflectance distribution function is calculated and, hence, available for other atmospheric or canopy reflectance models as a lower boundary condition. This technique is used together with an adding model to calculate several cases where Lambertian leaves possessing anisotropic leaf angle distributions yield non-Lambertian reflectance; similar behavior is exhibited for simulated soil surfaces.
Shafarevich, Igor Rostislavovich
1994-01-01
Shafarevich Basic Algebraic Geometry 2 The second edition of Shafarevich's introduction to algebraic geometry is in two volumes. The second volume covers schemes and complex manifolds, generalisations in two different directions of the affine and projective varieties that form the material of the first volume. Two notable additions in this second edition are the section on moduli spaces and representable functors, motivated by a discussion of the Hilbert scheme, and the section on Kähler geometry. The book ends with a historical sketch discussing the origins of algebraic geometry. From the Zentralblatt review of this volume: "... one can only respectfully repeat what has been said about the first part of the book (...): a great textbook, written by one of the leading algebraic geometers and teachers himself, has been reworked and updated. As a result the author's standard textbook on algebraic geometry has become even more important and valuable. Students, teachers, and active researchers using methods of al...
Optical geometry across the horizon
International Nuclear Information System (INIS)
Jonsson, Rickard
2006-01-01
In a recent paper (Jonsson and Westman 2006 Class. Quantum Grav. 23 61), a generalization of optical geometry, assuming a non-shearing reference congruence, is discussed. Here we illustrate that this formalism can be applied to (a finite four-volume) of any spherically symmetric spacetime. In particular we apply the formalism, using a non-static reference congruence, to do optical geometry across the horizon of a static black hole. While the resulting geometry in principle is time dependent, we can choose the reference congruence in such a manner that an embedding of the geometry always looks the same. Relative to the embedded geometry the reference points are then moving. We discuss the motion of photons, inertial forces and gyroscope precession in this framework
Geometry of illumination, luminance contrast, and gloss perception
Leloup, Frédéric; Pointer, Michael R.; Dutré, Philip; Hanselaer, Peter
2010-01-01
The influence of both the geometry of illumination and luminance contrast on gloss perception has been examined using the method of paired comparison. Six achromatic glass samples having different lightness were illuminated by two light sources. Only one of these light sources was visible in reflection by the observer. By separate adjustment of the intensity of both light sources, the luminance of both the reflected image and the adjacent off-specular surroundings could be individually varied...
Korsch, Dietrich
1991-01-01
This is the first book dedicated exclusively to all-reflective imaging systems. It is a teaching tool as well as a practical design tool for anyone who specializes in optics, particularly for those interested in telescopes, infrared, and grazing-incidence systems. The first part of the book describes a unified geometric optical theory of all-reflective imaging systems (from near-normal to grazing incidence) developed from basic principles. The second part discusses correction methods and a multitude of closed-form solutions of well-corrected systems, supplemented with many conventional and unc
Energy Technology Data Exchange (ETDEWEB)
Alvarado-Mendez, E.; Torres-Cisneros, M.; Gutierrez-Hernandez, D. A.; Andrade-Lucio, J. A.; Rojas-Lagunas, R.; Pedraza-Ortega, J. C.; Torres Cisneros, G. E. [Universidad de Guanajuato, Guanajuato (Mexico); Sanchez Mondragon, J. J. [Universidad Autonoma del Estado de Morelos, Morelos (Mexico); Flores-Alvarado, G. [Preparatoria por Cooperacion Domingo Arenas, Tlaxcala (Mexico)
2001-06-01
We study the reflection of one-dimensional spatial soliton at the nonlinear interface between a saturable type medium and linear medium. Our study makes emphasis on determining the physical conditions under which the beam reflected by the interface is still a spatial soliton. Depended the incidence angle we find three critical regions for spatial solitons in the interface. We observed nonlinear Goos- Haechen shift is determined if reflection angle are conserved. Finally, we present preliminary experimental results in SBN61:Ce of the total internal reflection of one dimensional beam. [Spanish] Estudiamos la reflexion de un soliton espacial unidimensional en una interfase formada por un medio no lineal saturable y un medio lineal. Nuestros estudios hacen enfasis en determinar las condiciones fisicas bajo las cuales el haz reflejado por la interfase no lineal sigue siendo soliton. Encontramos tres regiones criticas para un soliton especial en la interfase, dependiendo del valor que tome el angulo de incidencia. Asi mismo observamos corrimiento Goos-Haechen no lineal que es determinante para la conservacion del angulo de reflexion. Finalmente, presentamos resultados preliminares experimentales en SBN61:Ce de la reflexion interna total de un haz unidimensional.
Using Dance to Deepen Student Understanding of Geometry
Moore, Candice; Linder, Sandra M.
2012-01-01
This article provides an example of a collaborative effort between a dance specialist and four third-grade classroom teachers at an arts magnet school. They developed a dance and geometry integration project including implementation strategies, assessment tools, and reflections completed by both the classroom teacher and the third-grade students.…
Leung, W.S.; Coulter, D.A.; Moes, C.C.M.; Horvath, I.
2012-01-01
This paper presents a case study on the experience of delivering an Internet-based international collaborative semester course at intermediate postgraduate level and attempts to distill a model for exploring the success factors involved when presenting such courses. The pedagogic and practical
Complex analysis and CR geometry
Zampieri, Giuseppe
2008-01-01
Cauchy-Riemann (CR) geometry is the study of manifolds equipped with a system of CR-type equations. Compared to the early days when the purpose of CR geometry was to supply tools for the analysis of the existence and regularity of solutions to the \\bar\\partial-Neumann problem, it has rapidly acquired a life of its own and has became an important topic in differential geometry and the study of non-linear partial differential equations. A full understanding of modern CR geometry requires knowledge of various topics such as real/complex differential and symplectic geometry, foliation theory, the geometric theory of PDE's, and microlocal analysis. Nowadays, the subject of CR geometry is very rich in results, and the amount of material required to reach competence is daunting to graduate students who wish to learn it. However, the present book does not aim at introducing all the topics of current interest in CR geometry. Instead, an attempt is made to be friendly to the novice by moving, in a fairly relaxed way, f...
The geometry description markup language
International Nuclear Information System (INIS)
Chytracek, R.
2001-01-01
Currently, a lot of effort is being put on designing complex detectors. A number of simulation and reconstruction frameworks and applications have been developed with the aim to make this job easier. A very important role in this activity is played by the geometry description of the detector apparatus layout and its working environment. However, no real common approach to represent geometry data is available and such data can be found in various forms starting from custom semi-structured text files, source code (C/C++/FORTRAN), to XML and database solutions. The XML (Extensible Markup Language) has proven to provide an interesting approach for describing detector geometries, with several different but incompatible XML-based solutions existing. Therefore, interoperability and geometry data exchange among different frameworks is not possible at present. The author introduces a markup language for geometry descriptions. Its aim is to define a common approach for sharing and exchanging of geometry description data. Its requirements and design have been driven by experience and user feedback from existing projects which have their geometry description in XML
Energy Technology Data Exchange (ETDEWEB)
Wigger, Lothar; Buenger, Carsten (eds.) [Technische Univ. Dortmund (Germany). Bereich Allgemeine Erziehungswissenschaft; Platzer, Barbara [Technische Univ. Dortmund (Germany)
2017-08-01
The book on the educational and learning theoretical reflection of nuclear disasters as a consequence of Fukushima includes contributions on the following issues: pedagogical approach: children write on Fukushima, description of the reality as pedagogical challenge; lessons learned on the nuclear technology - perspectives and limits of pedagogical evaluation: moral education - Japanese teaching materials, educational challenges at the universities with respect to nuclear technology and technology impact assessment; education and technology - questions concerning the pedagogical responsibility: considerations on the responsibility of scientists, on the discrepancy between technology and education, disempowerment of the public by structural corruption - nuclear disaster and post-democratic tendencies in Japan.
Fallow), Stray
2009-01-01
Having trouble with geometry? Do Pi, The Pythagorean Theorem, and angle calculations just make your head spin? Relax. With Head First 2D Geometry, you'll master everything from triangles, quads and polygons to the time-saving secrets of similar and congruent angles -- and it'll be quick, painless, and fun. Through entertaining stories and practical examples from the world around you, this book takes you beyond boring problems. You'll actually use what you learn to make real-life decisions, like using angles and parallel lines to crack a mysterious CSI case. Put geometry to work for you, and
Walsh, Edward T
2014-01-01
This introductory text is designed to help undergraduate students develop a solid foundation in geometry. Early chapters progress slowly, cultivating the necessary understanding and self-confidence for the more rapid development that follows. The extensive treatment can be easily adapted to accommodate shorter courses. Starting with the language of mathematics as expressed in the algebra of logic and sets, the text covers geometric sets of points, separation and angles, triangles, parallel lines, similarity, polygons and area, circles, space geometry, and coordinate geometry. Each chapter incl
Differential geometry curves, surfaces, manifolds
Kohnel, Wolfgang
2002-01-01
This carefully written book is an introduction to the beautiful ideas and results of differential geometry. The first half covers the geometry of curves and surfaces, which provide much of the motivation and intuition for the general theory. Special topics that are explored include Frenet frames, ruled surfaces, minimal surfaces and the Gauss-Bonnet theorem. The second part is an introduction to the geometry of general manifolds, with particular emphasis on connections and curvature. The final two chapters are insightful examinations of the special cases of spaces of constant curvature and Einstein manifolds. The text is illustrated with many figures and examples. The prerequisites are undergraduate analysis and linear algebra.
PREFACE: Algebra, Geometry, and Mathematical Physics 2010
Stolin, A.; Abramov, V.; Fuchs, J.; Paal, E.; Shestopalov, Y.; Silvestrov, S.
2012-02-01
This proceedings volume presents results obtained by the participants of the 6th Baltic-Nordic workshop 'Algebra, Geometry, and Mathematical Physics (AGMP-6)' held at the Sven Lovén Centre for Marine Sciences in Tjärnö, Sweden on October 25-30, 2010. The Baltic-Nordic Network AGMP 'Algebra, Geometry, and Mathematical Physics' http://www.agmp.eu was created in 2005 on the initiative of two Estonian universities and two Swedish universities: Tallinn University of Technology represented by Eugen Paal (coordinator of the network), Tartu University represented by Viktor Abramov, Lund University represented by Sergei Silvestrov, and Chalmers University of Technology and the University of Gothenburg represented by Alexander Stolin. The goal was to promote international and interdisciplinary cooperation between scientists and research groups in the countries of the Baltic-Nordic region in mathematics and mathematical physics, with special emphasis on the important role played by algebra and geometry in modern physics, engineering and technologies. The main activities of the AGMP network consist of a series of regular annual international workshops, conferences and research schools. The AGMP network also constitutes an important educational forum for scientific exchange and dissimilation of research results for PhD students and Postdocs. The network has expanded since its creation, and nowadays its activities extend beyond countries in the Baltic-Nordic region to universities in other European countries and participants from elsewhere in the world. As one of the important research-dissimilation outcomes of its activities, the network has a tradition of producing high-quality research proceedings volumes after network events, publishing them with various international publishers. The PDF also contains the following: List of AGMP workshops and other AGMP activities Main topics discussed at AGMP-6 Review of AGMP-6 proceedings Acknowledgments List of Conference Participants
Ferrero, Alejandro; Rabal, Ana; Campos, Joaquín; Martínez-Verdú, Francisco; Chorro, Elísabet; Perales, Esther; Pons, Alicia; Hernanz, María Luisa
2013-02-01
A reduced set of measurement geometries allows the spectral reflectance of special effect coatings to be predicted for any other geometry. A physical model based on flake-related parameters has been used to determine nonredundant measurement geometries for the complete description of the spectral bidirectional reflectance distribution function (BRDF). The analysis of experimental spectral BRDF was carried out by means of principal component analysis. From this analysis, a set of nine measurement geometries was proposed to characterize special effect coatings. It was shown that, for two different special effect coatings, these geometries provide a good prediction of their complete color shift.
McGlinchey, S.
2017-01-01
A ‘Day 0’ introduction to International Relations for beginners. Written by a range of emerging and established experts, the chapters offer a broad sweep of the basic components of International Relations and the key contemporary issues that concern the discipline. The narrative arc forms a complete circle, taking readers from no knowledge to competency. The journey starts by examining how the international system was formed and ends by reflecting that International Relations is always adapti...
Zhu, Chun-Sheng; Lin, Zhi-Jian; Xiao, Ming-Liang; Niu, Hong-Juan; Zhang, Bing
2016-03-01
Since the chromatographic fingerprint was introduced, it has been accepted by many countries to assess the quality and authenticity of Chinese herbal medicine (CHM). However, solely using the chromatographic fingerprint to assay numerous chemicals is not suitable for the assessment of the whole internal quality and pharmacodynamics of CHM. Consequently, it is necessary to develop a rational approach to connecting the chromatographic fingerprint with effective components to assess the internal quality of CHM. For this purpose, a spectrum-effect relationship theory was proposed and accepted as a new method for the assessment of CHM because of its potential use to screen effective components from CHM. In this paper, we systematically reviewed the application of the spectrum-effect relationship theory in the research of CHM, including research mentality, different chromatographic analysis techniques, data processing technologies, and structure determination. Copyright © 2016 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.
Directory of Open Access Journals (Sweden)
Carla Bagnoli
2018-04-01
Full Text Available The purpose of this paper is to highlight some difficulties of Neil Sinhababu’s Humean theory of agency, which depend on his radically reductivist approach, rather than to his Humean sympathies. The argument is that Sinhababu’s theory builds upon a critique of reflective agency which is based on equivocation and misunderstandings of the Kantian approach. Ultimately, the objection is that his reductivist view is unequipped to address the rclassical problems of rational deliberation and agential authority.
Advances in discrete differential geometry
2016-01-01
This is one of the first books on a newly emerging field of discrete differential geometry and an excellent way to access this exciting area. It surveys the fascinating connections between discrete models in differential geometry and complex analysis, integrable systems and applications in computer graphics. The authors take a closer look at discrete models in differential geometry and dynamical systems. Their curves are polygonal, surfaces are made from triangles and quadrilaterals, and time is discrete. Nevertheless, the difference between the corresponding smooth curves, surfaces and classical dynamical systems with continuous time can hardly be seen. This is the paradigm of structure-preserving discretizations. Current advances in this field are stimulated to a large extent by its relevance for computer graphics and mathematical physics. This book is written by specialists working together on a common research project. It is about differential geometry and dynamical systems, smooth and discrete theories, ...
Hyperbolic Metamaterials with Complex Geometry
DEFF Research Database (Denmark)
Lavrinenko, Andrei; Andryieuski, Andrei; Zhukovsky, Sergei
2016-01-01
We investigate new geometries of hyperbolic metamaterialssuch as highly corrugated structures, nanoparticle monolayer assemblies, super-structured or vertically arranged multilayersand nanopillars. All structures retain basic propertiesof hyperbolic metamaterials, but have functionality improved...
An introduction to differential geometry
Willmore, T J
2012-01-01
This text employs vector methods to explore the classical theory of curves and surfaces. Topics include basic theory of tensor algebra, tensor calculus, calculus of differential forms, and elements of Riemannian geometry. 1959 edition.
Symplectic geometry and Fourier analysis
Wallach, Nolan R
2018-01-01
Suitable for graduate students in mathematics, this monograph covers differential and symplectic geometry, homogeneous symplectic manifolds, Fourier analysis, metaplectic representation, quantization, Kirillov theory. Includes Appendix on Quantum Mechanics by Robert Hermann. 1977 edition.
Topology and geometry for physicists
Nash, Charles
1983-01-01
Differential geometry and topology are essential tools for many theoretical physicists, particularly in the study of condensed matter physics, gravity, and particle physics. Written by physicists for physics students, this text introduces geometrical and topological methods in theoretical physics and applied mathematics. It assumes no detailed background in topology or geometry, and it emphasizes physical motivations, enabling students to apply the techniques to their physics formulas and research. ""Thoroughly recommended"" by The Physics Bulletin, this volume's physics applications range fr
Spectral dimension of quantum geometries
International Nuclear Information System (INIS)
Calcagni, Gianluca; Oriti, Daniele; Thürigen, Johannes
2014-01-01
The spectral dimension is an indicator of geometry and topology of spacetime and a tool to compare the description of quantum geometry in various approaches to quantum gravity. This is possible because it can be defined not only on smooth geometries but also on discrete (e.g., simplicial) ones. In this paper, we consider the spectral dimension of quantum states of spatial geometry defined on combinatorial complexes endowed with additional algebraic data: the kinematical quantum states of loop quantum gravity (LQG). Preliminarily, the effects of topology and discreteness of classical discrete geometries are studied in a systematic manner. We look for states reproducing the spectral dimension of a classical space in the appropriate regime. We also test the hypothesis that in LQG, as in other approaches, there is a scale dependence of the spectral dimension, which runs from the topological dimension at large scales to a smaller one at short distances. While our results do not give any strong support to this hypothesis, we can however pinpoint when the topological dimension is reproduced by LQG quantum states. Overall, by exploring the interplay of combinatorial, topological and geometrical effects, and by considering various kinds of quantum states such as coherent states and their superpositions, we find that the spectral dimension of discrete quantum geometries is more sensitive to the underlying combinatorial structures than to the details of the additional data associated with them. (paper)
DEFF Research Database (Denmark)
Blasco, Maribel
2012-01-01
produces: that the self is accessible and transcendable, that reflexivity is universal across space and time, and that the self can act as its own remedial change agent or ‘inner consultant.’ I argue that because reflexivity is understood in many different ways, attention to definition is crucial, both...... on the concepts of selfhood that prevail and how notions of difference are constructed. First, I discuss how the dominant usages of reflexivity in intercultural education reflect and reproduce a Cartesian view of the self that shapes how ICC is conceptualized and taught. I discuss three assumptions that this view...
DEFF Research Database (Denmark)
Muchie, Mammo
2011-01-01
A numberof Chris Freeman's colleagues were asked to reflect on what they thought describes his life and work in a few words. Some of the colleagues replied including former SPRU students that were taught or supervised by Chris Freeman. Their views on what they thought were Chris Freeman's defining...... life is not free from fluctuations, cycles, disruptions, crises and destructions both human and ecological. Innovation research ought to position itself to address environmental, financial and economic crises. The third is innovation research for development by addressing not only poverty erdaication...
DEFF Research Database (Denmark)
Ahrenkiel Jørgensen, Andriette
2016-01-01
In Breve fra min Have (Letters from my Garden), the Swedish landscape architect, Sven-Ingvar Andersson, produces dialogues about his garden to a wide circle of friends, colleagues, deceased and still living acquaintances such as Karen Blixen, Gertrude Stein, C. Th. Sørensen, Albrecht Dürer, Peter...... Høeg etetera. The dialogues work as a tool of reflection in terms of providing opportunity to examine his own beliefs, to explore the possible reasons for engaging in a particular activity. On the basis of Sven-Ingvar Andersson’s book a teaching program at the Aarhus School of Architecture provides...
1994-01-01
The aluminized polymer film used in spacecraft as a radiation barrier to protect both astronauts and delicate instruments has led to a number of spinoff applications. Among them are aluminized shipping bags, food cart covers and medical bags. Radiant Technologies purchases component materials and assembles a barrier made of layers of aluminized foil. The packaging reflects outside heat away from the product inside the container. The company is developing new aluminized lines, express mailers, large shipping bags, gel packs and insulated panels for the building industry.
Directory of Open Access Journals (Sweden)
Mariya Riekkinen
2016-01-01
Full Text Available This article deals with the much debated issue of children’s public participation from the perspective of legal practices in the Russian Federation. Having emerged at the level of national jurisdictions, the practice of engaging minors in decision-making processes on issues of public significance – or the practice of public participation of children – is stipulated by the UN Committee on the Rights of the Child, based on Article 12 of the UN Convention on the Rights of the Child. Public participation of minors implies that children have clearly defined opportunities to take part in decision-making processes concerning those political and public matters affecting their interests.Albeit limited by the clause “regarding the issues concerning them,” the claims for such participation are dictated by emerging standards of international law. The author has examined the process of devising these standards in Russian public law. Moreover, an analysis of the evolution of academic views on public participation of children in Russian legal scholarship is also included in this article.Relying extensively on the method of legal analysis and the comparative analysis of the conformity of national public law standards with respect to international law, the author proposes several legal amendments to the Federal law “On the Basic Guarantees of the Rights of the Child in the Russian Federation,” which would lead to anchoring more solidly the participatory right of minors in the legal system of the Russian Federation.
Flexible intuitions of Euclidean geometry in an Amazonian indigene group
Izard, Véronique; Pica, Pierre; Spelke, Elizabeth S.; Dehaene, Stanislas
2011-01-01
Kant argued that Euclidean geometry is synthesized on the basis of an a priori intuition of space. This proposal inspired much behavioral research probing whether spatial navigation in humans and animals conforms to the predictions of Euclidean geometry. However, Euclidean geometry also includes concepts that transcend the perceptible, such as objects that are infinitely small or infinitely large, or statements of necessity and impossibility. We tested the hypothesis that certain aspects of nonperceptible Euclidian geometry map onto intuitions of space that are present in all humans, even in the absence of formal mathematical education. Our tests probed intuitions of points, lines, and surfaces in participants from an indigene group in the Amazon, the Mundurucu, as well as adults and age-matched children controls from the United States and France and younger US children without education in geometry. The responses of Mundurucu adults and children converged with that of mathematically educated adults and children and revealed an intuitive understanding of essential properties of Euclidean geometry. For instance, on a surface described to them as perfectly planar, the Mundurucu's estimations of the internal angles of triangles added up to ∼180 degrees, and when asked explicitly, they stated that there exists one single parallel line to any given line through a given point. These intuitions were also partially in place in the group of younger US participants. We conclude that, during childhood, humans develop geometrical intuitions that spontaneously accord with the principles of Euclidean geometry, even in the absence of training in mathematics. PMID:21606377
Proximal Femoral Geometry and the Risk of Fractures: Literature Review
Directory of Open Access Journals (Sweden)
N.V. Grygorieva
2016-02-01
Full Text Available This article presents the literature review of the impact of the upper third of the femur geometry (hip axis length, femoral neck angle, inter-trochanteric length, horizontal offset, thickness of the cortical bone, etc. on the risk of fractures. The article demonstrates the capabilities of techniques for measurement of hip geometry, namely conventional X-ray of pelvic bones, dual-energy X-ray absorptiometry, computed tomography. Possible correlation is shown between some genetic markers and features of the geometry of the upper third of the femur. Also, there are presented the results of own researches of age and sex characteristics of proximal hip geometry parameters in patients without fractures, as well as in patients of older age groups with internal and extraarticular femoral fractures.
Directory of Open Access Journals (Sweden)
Cousin Fabrice
2015-01-01
Full Text Available The specular neutron reflectivity is a technique enabling the measurement of neutron scattering length density profile perpendicular to the plane of a surface or an interface, and thereby the profile of chemical composition. The characteristic sizes that are probed range from around 5 Å up 5000 Å. It is a scattering technique that averages information on the entire surface and it is therefore not possible to obtain information within the plane of the interface. The specific properties of neutrons (possibility of tuning the contrast by isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons makes it particularly interesting in the fields of soft matter, biophysics and magnetic thin films. This course is a basic introduction to the technique and does not address the magnetic reflectivity. It is composed of three parts describing respectively its principle and its formalism, the experimental aspects of the method (spectrometers, samples and two examples related to the materials for energy.
Directory of Open Access Journals (Sweden)
Mitzkat, Anika
2016-04-01
Full Text Available The terminology which has been used up until now within interprofessional healthcare has been characterised by a certain definitional weakness, which, among other factors, has been caused by an uncritical adoption of language conventions and a lack of theoretical reflection. However, as terminological clarity plays a significant role in the development and profiling of a discipline, the clarification and definition of commonly-used terminology has manifested itself as a considerable objective for the interprofessional research community. One of the most important journals for research in the area of interprofessional education and care, the Journal of Interprofessional Care, has expanded its author guidelines relating to terminology, modeled after the conceptual considerations of the research group around Barr et. al and Reeves et al. A German translation of the suggested terms therein has been presented in this contribution, and discussed in light of the challenges to a possible adaptation for the German-speaking world. The objective is to assist communication in practice and research in becoming clearer, while promoting an increasing awareness to and the transparency of determined definitions and terminologies.
Directory of Open Access Journals (Sweden)
Lucía Inés Coppa
2014-12-01
Full Text Available The following article intends to approach some aspects of bourdiean thoughts in order to develop an approach to the notion of gender and the way in which – within an androcentric symbolic order and a normative heterosexual matrix – function these diagrams in the way gender makes up the subjective corporal form. From those notions, we want to reflect about the emergency of sexual identities that transgress the cultural precepts around gender founded in doxic experience. Likewise, we will sketch a brief reference among inconscient dimension across psychoanalytical tradition and performative theory across Judith Butler in the feminists debates.Through this conceptual framework we will attempt to examine how may the dominant representations of femininity, androcentric and heterosexually regulated, influence the identity formation of a feminine transsexual person, founded in the morphological ideal which has sustenance in the man-woman dichotomy, leaving the questioning open about the ways that the transgressive assumption of sex of what appears like the order of things may take in a binomic gender matrix, examining the reception of this debates in te Gender Identity Law N° 26.743
Obtaining local reflectivity at two-way travel time by filtering acoustic reflection data
Slob, E.C.; Zhang, L.; Wapenaar, C.P.A.; Mihai Popovici, A.; Fomel, S.
2017-01-01
A modified implementation of Marchenko redatuming leads to a filter that removes internal multiples from reflection data. It produces local reflectivity at two-way travel time. The method creates new primary reflections resulting from emitted events that eliminate internal multiples. We call these
Variable geometry Darrieus wind machine
Pytlinski, J. T.; Serrano, D.
1983-08-01
A variable geometry Darrieus wind machine is proposed. The lower attachment of the blades to the rotor can move freely up and down the axle allowing the blades of change shape during rotation. Experimental data for a 17 m. diameter Darrieus rotor and a theoretical model for multiple streamtube performance prediction were used to develop a computer simulation program for studying parameters that affect the machine's performance. This new variable geometry concept is described and interrelated with multiple streamtube theory through aerodynamic parameters. The computer simulation study shows that governor behavior of a Darrieus turbine can not be attained by a standard turbine operating within normally occurring rotational velocity limits. A second generation variable geometry Darrieus wind turbine which uses a telescopic blade is proposed as a potential improvement on the studied concept.
Flux compactifications and generalized geometries
International Nuclear Information System (INIS)
Grana, Mariana
2006-01-01
Following the lectures given at CERN Winter School 2006, we present a pedagogical overview of flux compactifications and generalized geometries, concentrating on closed string fluxes in type II theories. We start by reviewing the supersymmetric flux configurations with maximally symmetric four-dimensional spaces. We then discuss the no-go theorems (and their evasion) for compactifications with fluxes. We analyse the resulting four-dimensional effective theories for Calabi-Yau and Calabi-Yau orientifold compactifications, concentrating on the flux-induced superpotentials. We discuss the generic mechanism of moduli stabilization and illustrate with two examples: the conifold in IIB and a T 6 /(Z 3 x Z 3 ) torus in IIA. We finish by studying the effective action and flux vacua for generalized geometries in the context of generalized complex geometry
Flux compactifications and generalized geometries
Energy Technology Data Exchange (ETDEWEB)
Grana, Mariana [Service de Physique Theorique, CEA/Saclay, 91191 Gif-sur-Yvette Cedex (France)
2006-11-07
Following the lectures given at CERN Winter School 2006, we present a pedagogical overview of flux compactifications and generalized geometries, concentrating on closed string fluxes in type II theories. We start by reviewing the supersymmetric flux configurations with maximally symmetric four-dimensional spaces. We then discuss the no-go theorems (and their evasion) for compactifications with fluxes. We analyse the resulting four-dimensional effective theories for Calabi-Yau and Calabi-Yau orientifold compactifications, concentrating on the flux-induced superpotentials. We discuss the generic mechanism of moduli stabilization and illustrate with two examples: the conifold in IIB and a T{sup 6} /(Z{sub 3} x Z{sub 3}) torus in IIA. We finish by studying the effective action and flux vacua for generalized geometries in the context of generalized complex geometry.
Guide to Computational Geometry Processing
DEFF Research Database (Denmark)
Bærentzen, Jakob Andreas; Gravesen, Jens; Anton, François
be processed before it is useful. This Guide to Computational Geometry Processing reviews the algorithms for processing geometric data, with a practical focus on important techniques not covered by traditional courses on computer vision and computer graphics. This is balanced with an introduction...... to the theoretical and mathematical underpinnings of each technique, enabling the reader to not only implement a given method, but also to understand the ideas behind it, its limitations and its advantages. Topics and features: Presents an overview of the underlying mathematical theory, covering vector spaces......, metric space, affine spaces, differential geometry, and finite difference methods for derivatives and differential equations Reviews geometry representations, including polygonal meshes, splines, and subdivision surfaces Examines techniques for computing curvature from polygonal meshes Describes...
Electrodynamics and Spacetime Geometry: Foundations
Cabral, Francisco; Lobo, Francisco S. N.
2017-02-01
We explore the intimate connection between spacetime geometry and electrodynamics. This link is already implicit in the constitutive relations between the field strengths and excitations, which are an essential part of the axiomatic structure of electromagnetism, clearly formulated via integration theory and differential forms. We review the foundations of classical electromagnetism based on charge and magnetic flux conservation, the Lorentz force and the constitutive relations. These relations introduce the conformal part of the metric and allow the study of electrodynamics for specific spacetime geometries. At the foundational level, we discuss the possibility of generalizing the vacuum constitutive relations, by relaxing the fixed conditions of homogeneity and isotropy, and by assuming that the symmetry properties of the electro-vacuum follow the spacetime isometries. The implications of this extension are briefly discussed in the context of the intimate connection between electromagnetism and the geometry (and causal structure) of spacetime.
Dayside merging and cusp geometry
International Nuclear Information System (INIS)
Crooker, N.U.
1979-01-01
Geometrical considerations are presented to show that dayside magnetic merging when constrained to act only where the fields are antiparallel results in lines of merging that converge at the polar cusps. An important consequence of this geometry is that no accelerated flows are predicted across the dayside magnetopause. Acceleration owing to merging acts in opposition to the magnetosheath flow at the merging point and produces the variably directed, slower-than-magnetosheath flows observed in the entry layer. Another consequence of the merging geometry is that much of the time closed field lines constitute the subsolar region of the magnetopause. The manner in which the polar cap convection patterns predicted by the proposed geometry change as the interplanetary field is rotated through 360 0 provides a unifying description of how the observed single circular vortex and the crescent-shaped double vortex patterns mutually evolve under the influence of a single operating principle
DOGBONE GEOMETRY FOR RECIRCULATING ACCELERATORS
International Nuclear Information System (INIS)
BERG, J.S.; JOHNSTONE, C.; SUMMERS, D.
2001-01-01
Most scenarios for accelerating muons require recirculating acceleration. A racetrack shape for the accelerator requires particles with lower energy in early passes to traverse almost the same length of arc as particles with the highest energy. This extra arc length may lead to excess decays and excess cost. Changing the geometry to a dogbone shape, where there is a single linac and the beam turns completely around at the end of the linac, returning to the same end of the linac from which it exited, addresses this problem. In this design, the arc lengths can be proportional to the particle's momentum. This paper proposes an approximate cost model for a recirculating accelerator, attempts to make cost-optimized designs for both racetrack and dogbone geometries, and demonstrates that the dogbone geometry does appear to be more cost effective
Total-reflection X-ray fluorescence analysis of Austrian wine
Energy Technology Data Exchange (ETDEWEB)
Gruber, X. [Atominstitut der Osterreichischen Universitaeten, 1020 Vienna (Austria); Kregsamer, P. [Atominstitut der Osterreichischen Universitaeten, 1020 Vienna (Austria); Wobrauschek, P. [Atominstitut der Osterreichischen Universitaeten, 1020 Vienna (Austria); Streli, C. [Atominstitut der Osterreichischen Universitaeten, 1020 Vienna (Austria)]. E-mail: streli@ati.ac.at
2006-11-15
The concentration of major, minor and trace elements in Austrian wine was determined by total-reflection X-ray fluorescence using gallium as internal standard. A multi-elemental analysis was possible by pipetting 6 {mu}l of wine directly on the reflector and drying. Total-reflection X-ray fluorescence analysis was performed with Atomika EXTRA II A (Cameca) X-rays from a Mo tube with a high-energy cut-off at 20 keV in total-reflection geometry. The results showed that it was possible to identify only by the elemental analysis as fingerprint the vineyards and year of vintage among 11 different wines.
Total-reflection X-ray fluorescence analysis of Austrian wine
International Nuclear Information System (INIS)
Gruber, X.; Kregsamer, P.; Wobrauschek, P.; Streli, C.
2006-01-01
The concentration of major, minor and trace elements in Austrian wine was determined by total-reflection X-ray fluorescence using gallium as internal standard. A multi-elemental analysis was possible by pipetting 6 μl of wine directly on the reflector and drying. Total-reflection X-ray fluorescence analysis was performed with Atomika EXTRA II A (Cameca) X-rays from a Mo tube with a high-energy cut-off at 20 keV in total-reflection geometry. The results showed that it was possible to identify only by the elemental analysis as fingerprint the vineyards and year of vintage among 11 different wines
Directory of Open Access Journals (Sweden)
Peter Šenk
2013-07-01
Full Text Available The paper presents the international urban-architectural workshop Maribor-South (2010-11 as a model for “Maribor’s” urban-architectural workshops, which urban planners evaluate and use to direct urban development and theoretical discussion. The presented interdisciplinary project explored possibilities for designing the southern edge of the city in the area where the southern bypass construction is planned. In addition describing the example of the workshop, which develops the theoretical field through a “practical and project approach” with the defined project basis, i.e. the defined area of discussion and project issue, the paper also highlights the opportunity for a “theoretical approach”. The theoretical approach aims at providing a wider insight into the related theoretical field based on a generalised spatial issue. As one of the key priorities of contemporary urban planning and sustainable urban redevelopment, the planned direction of urban development in the areas of constructing transport infrastructure, which is evident in the first approach, moves into a wider referential field (no longer directly related to the project with the second approach by examining the issues of mobility, space, place, diversity of infrastructures of contemporary space, etc. While in the first approach developing design concepts strives for theoretical conceptualisation, the second approach facilitates focusing on finding links between the theoretical concept and manifestations in real space, though the approaches are always separated. Their operationality is possible only on the level of “combinatorial thinking” and remains beyond direct instrumentality.
Geometric Transformations in Engineering Geometry
Directory of Open Access Journals (Sweden)
I. F. Borovikov
2015-01-01
Full Text Available Recently, for business purposes, in view of current trends and world experience in training engineers, research and faculty staff there has been a need to transform traditional courses of descriptive geometry into the course of engineering geometry in which the geometrical transformations have to become its main section. On the basis of critical analysis the paper gives suggestions to improve a presentation technique of this section both in the classroom and in academic literature, extend an application scope of geometrical transformations to solve the position and metric tasks and simulation of surfaces, as well as to design complex engineering configurations, which meet a number of pre-specified conditions.The article offers to make a number of considerable amendments to the terms and definitions used in the existing courses of descriptive geometry. It draws some conclusions and makes the appropriate proposals on feasibility of coordination in teaching the movement transformation in the courses of analytical and descriptive geometry. This will provide interdisciplinary team teaching and allow students to be convinced that a combination of analytical and graphic ways to solve geometric tasks is useful and reasonable.The traditional sections of learning courses need to be added with a theory of projective and bi-rational transformations. In terms of application simplicity and convenience it is enough to consider the central transformations when solving the applied tasks. These transformations contain a beam of sub-invariant (low-invariant straight lines on which the invariant curve induces non-involution and involution projectivities. The expediency of nonlinear transformations application is shown in the article by a specific example of geometric modeling of the interfacing surface "spar-blade".Implementation of these suggestions will contribute to a real transformation of a traditional course of descriptive geometry to the engineering geometry
2011-02-01
The nebula Messier 78 takes centre stage in this image taken with the Wide Field Imager on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile, while the stars powering the bright display take a backseat. The brilliant starlight ricochets off dust particles in the nebula, illuminating it with scattered blue light. Igor Chekalin was the overall winner of ESO's Hidden Treasures 2010 astrophotography competition with his image of this stunning object. Messier 78 is a fine example of a reflection nebula. The ultraviolet radiation from the stars that illuminate it is not intense enough to ionise the gas to make it glow - its dust particles simply reflect the starlight that falls on them. Despite this, Messier 78 can easily be observed with a small telescope, being one of the brightest reflection nebulae in the sky. It lies about 1350 light-years away in the constellation of Orion (The Hunter) and can be found northeast of the easternmost star of Orion's belt. This new image of Messier 78 from the MPG/ESO 2.2-metre telescope at the La Silla Observatory is based on data selected by Igor Chekalin in his winning entry to the Hidden Treasures competition [1]. The pale blue tint seen in the nebula in this picture is an accurate representation of its dominant colour. Blue hues are commonly seen in reflection nebulae because of the way the starlight is scattered by the tiny dust particles that they contain: the shorter wavelength of blue light is scattered more efficiently than the longer wavelength red light. This image contains many other striking features apart from the glowing nebula. A thick band of obscuring dust stretches across the image from the upper left to the lower right, blocking the light from background stars. In the bottom right corner, many curious pink structures are also visible, which are created by jets of material being ejected from stars that have recently formed and are still buried deep in dust clouds. Two bright stars, HD 38563A and
Graphical debugging of combinational geometry
International Nuclear Information System (INIS)
Burns, T.J.; Smith, M.S.
1992-01-01
A graphical debugger for combinatorial geometry being developed at Oak Ridge National Laboratory is described. The prototype debugger consists of two parts: a FORTRAN-based ''view'' generator and a Microsoft Windows application for displaying the geometry. Options and features of both modules are discussed. Examples illustrating the various options available are presented. The potential for utilizing the images produced using the debugger as a visualization tool for the output of the radiation transport codes is discussed as is the future direction of the development
Lectures on Algebraic Geometry I
Harder, Gunter
2012-01-01
This book and the following second volume is an introduction into modern algebraic geometry. In the first volume the methods of homological algebra, theory of sheaves, and sheaf cohomology are developed. These methods are indispensable for modern algebraic geometry, but they are also fundamental for other branches of mathematics and of great interest in their own. In the last chapter of volume I these concepts are applied to the theory of compact Riemann surfaces. In this chapter the author makes clear how influential the ideas of Abel, Riemann and Jacobi were and that many of the modern metho
Combinatorial geometry in the plane
Hadwiger, Hugo; Klee, Victor
2014-01-01
Geared toward advanced undergraduates familiar with analysis and college geometry, this concise book discusses theorems on topics restricted to the plane such as convexity, coverings, and graphs. In addition to helping students cultivate rigorous thought, the text encourages the development of mathematical intuition and clarifies the nature of mathematical research.The two-part treatment begins with specific topics including integral distances, covering problems, point set geometry and convexity, simple paradoxes involving point sets, and pure combinatorics, among other subjects. The second pa
Modern differential geometry for physicists
Isham, C J
1989-01-01
These notes are the content of an introductory course on modern, coordinate-free differential geometry which is taken by the first-year theoretical physics PhD students, or by students attending the one-year MSc course "Fundamental Fields and Forces" at Imperial College. The book is concerned entirely with mathematics proper, although the emphasis and detailed topics have been chosen with an eye to the way in which differential geometry is applied these days to modern theoretical physics. This includes not only the traditional area of general relativity but also the theory of Yang-Mills fields
Comparison theorems in Riemannian geometry
Cheeger, Jeff
2008-01-01
The central theme of this book is the interaction between the curvature of a complete Riemannian manifold and its topology and global geometry. The first five chapters are preparatory in nature. They begin with a very concise introduction to Riemannian geometry, followed by an exposition of Toponogov's theorem-the first such treatment in a book in English. Next comes a detailed presentation of homogeneous spaces in which the main goal is to find formulas for their curvature. A quick chapter of Morse theory is followed by one on the injectivity radius. Chapters 6-9 deal with many of the most re
Geometry, topology, and string theory
Energy Technology Data Exchange (ETDEWEB)
Varadarajan, Uday [Univ. of California, Berkeley, CA (United States)
2003-01-01
A variety of scenarios are considered which shed light upon the uses and limitations of classical geometric and topological notions in string theory. The primary focus is on situations in which D-brane or string probes of a given classical space-time see the geometry quite differently than one might naively expect. In particular, situations in which extra dimensions, non-commutative geometries as well as other non-local structures emerge are explored in detail. Further, a preliminary exploration of such issues in Lorentzian space-times with non-trivial causal structures within string theory is initiated.
Spatial geometry and special relativity
DEFF Research Database (Denmark)
Kneubil, Fabiana Botelho
2016-01-01
In this work, it is shown the interplay of relative and absolute entities, which are present in both spatial geometry and special relativity. In order to strengthen the understanding of special relativity, we discuss firstly an instance of geometry and the existence of both frame......-dependent and frame-independent entities. We depart from a subject well known by students, which is the three-dimensional geometric space in order to compare, afterwards, with the treatment of four-dimensional space in the special relativity. The differences and similarities between these two subjects are also...
Stochastic geometry and its applications
Chiu, Sung Nok; Kendall, Wilfrid S; Mecke, Joseph
2013-01-01
An extensive update to a classic text Stochastic geometry and spatial statistics play a fundamental role in many modern branches of physics, materials sciences, engineering, biology and environmental sciences. They offer successful models for the description of random two- and three-dimensional micro and macro structures and statistical methods for their analysis. The previous edition of this book has served as the key reference in its field for over 18 years and is regarded as the best treatment of the subject of stochastic geometry, both as a subject with vital a
Introduction to topology and geometry
Stahl, Saul
2014-01-01
An easily accessible introduction to over three centuries of innovations in geometry Praise for the First Edition ". . . a welcome alternative to compartmentalized treatments bound to the old thinking. This clearly written, well-illustrated book supplies sufficient background to be self-contained." -CHOICE This fully revised new edition offers the most comprehensive coverage of modern geometry currently available at an introductory level. The book strikes a welcome balance between academic rigor and accessibility, providing a complete and cohesive picture of the science with an unparallele
Algebraic geometry and theta functions
Coble, Arthur B
1929-01-01
This book is the result of extending and deepening all questions from algebraic geometry that are connected to the central problem of this book: the determination of the tritangent planes of a space curve of order six and genus four, which the author treated in his Colloquium Lecture in 1928 at Amherst. The first two chapters recall fundamental ideas of algebraic geometry and theta functions in such fashion as will be most helpful in later applications. In order to clearly present the state of the central problem, the author first presents the better-known cases of genus two (Chapter III) and
Geometry, topology, and string theory
International Nuclear Information System (INIS)
Varadarajan, Uday
2003-01-01
A variety of scenarios are considered which shed light upon the uses and limitations of classical geometric and topological notions in string theory. The primary focus is on situations in which D-brane or string probes of a given classical space-time see the geometry quite differently than one might naively expect. In particular, situations in which extra dimensions, non-commutative geometries as well as other non-local structures emerge are explored in detail. Further, a preliminary exploration of such issues in Lorentzian space-times with non-trivial causal structures within string theory is initiated
Shaw, Malcolm N
2017-01-01
International Law is the definitive and authoritative text on the subject, offering Shaw's unbeatable combination of clarity of expression and academic rigour and ensuring both understanding and critical analysis in an engaging and authoritative style. Encompassing the leading principles, practice and cases, and retaining and developing the detailed references which encourage and assist the reader in further study, this new edition motivates and challenges students and professionals while remaining accessible and engaging. Fully updated to reflect recent case law and treaty developments, this edition contains an expanded treatment of the relationship between international and domestic law, the principles of international humanitarian law, and international criminal law alongside additional material on international economic law.
Felder-Puig, Rosemarie; Griebler, Robert; Samdal, Oddrun; King, Matthew A; Freeman, John; Duer, Wolfgang
2012-09-01
Given the pressure that educators and policy makers are under to achieve academic standards for students, understanding the relationship of academic success to various aspects of health is important. The international Health Behavior in School-Aged Children (HBSC) questionnaire, being used in 41 countries with different school and grading systems, has contained an item assessing perceived school performance (PSP) since 1986. Whereas the test-retest reliability of this item has been reported previously, we determined its convergent and discriminant validity. This cross-sectional study used anonymous self-report data from Austrian (N = 266), Norwegian (N = 240), and Canadian (N = 9,717) samples. Students were between 10 and 17 years old. PSP responses were compared to the self-reported average school grades in 6 subjects (Austria) or 8 subjects (Norway), respectively, or to a general, 5-category-based appraisal of most recent school grades (Canada). Correlations between PSP and self-reported average school grade scores were between 0.51 and 0.65, representing large effect sizes. Differences between the median school grades in the 4 categories of the PSP item were statistically significant in all 3 samples. The PSP item showed predominantly small associations with some randomly selected HBSC items or scales designed to measure different concepts. The PSP item seems to be a valid and useful question that can distinguish groups of respondents that get good grades at school from those that do not. The meaning of PSP may be context-specific and may have different connotations across student populations from different countries with different school systems. © 2012, American School Health Association.
Radar reflection off extensive air showers
Stasielak, J; Bertaina, M; Blümer, J; Chiavassa, A; Engel, R; Haungs, A; Huege, T; Kampert, K -H; Klages, H; Kleifges, M; Krömer, O; Ludwig, M; Mathys, S; Neunteufel, P; Pekala, J; Rautenberg, J; Riegel, M; Roth, M; Salamida, F; Schieler, H; Šmída, R; Unger, M; Weber, M; Werner, F; Wilczyński, H; Wochele, J
2012-01-01
We investigate the possibility of detecting extensive air showers by the radar technique. Considering a bistatic radar system and different shower geometries, we simulate reflection of radio waves off the static plasma produced by the shower in the air. Using the Thomson cross-section for radio wave reflection, we obtain the time evolution of the signal received by the antennas. The frequency upshift of the radar echo and the power received are studied to verify the feasibility of the radar detection technique.
The Idea of Order at Geometry Class.
Rishel, Thomas
The idea of order in geometry is explored using the experience of assignments given to undergraduates in a college geometry course "From Space to Geometry." Discussed are the definition of geometry, and earth measurement using architecture, art, and common experience. This discussion concludes with a consideration of the question of whether…
Teaching Spatial Geometry in a Virtual World
DEFF Research Database (Denmark)
Förster, Klaus-Tycho
2017-01-01
Spatial geometry is one of the fundamental mathematical building blocks of any engineering education. However, it is overshadowed by planar geometry in the curriculum between playful early primary education and later analytical geometry, leaving a multi-year gap where spatial geometry is absent...
Directory of Open Access Journals (Sweden)
Arno Tausch
2013-01-01
Full Text Available BackgroundThis article looks at the long-term, structural determinants of environmental and public health performance in the world system. MethodsIn multiple standard ordinary least squares (OLS regression models, we tested the effects of 26 standard predictor variables, including the ‘four freedoms’ of goods, capital, labour and services, on the following indicators of sustainable development and public health: avoiding net trade of ecological footprint global hectare (gha per person; avoiding high carbon emissions per million US dollars GDP; avoiding high CO2 per capita (gha/cap; avoiding high ecological footprint per capita; avoiding becoming victim of natural disasters; a good performance on the Environmental Performance Index (EPI; a good performance on the Happy Life Years (HLYs scale; and a good performance on the Happy Planet Index (HPI. ResultsOur research showed that the apprehensions of quantitative research, critical of neo-liberal globalization, are fully vindicated by the significant negative environmental and public health effects of the foreign savings rate. High foreign savings are indeed a driver of global footprint, and are a blockade against a satisfactory HPI performance. The new international division of labour is one of the prime drivers of high CO2 per capita emissions. Multinational Corporation (MNC penetration, the master variable of most quantitative dependency theories, blocks EPI and several other socially important processes. Worker remittances have a significant positive effect on the HPI, and HLYs. ConclusionWe re-analysed the solid macro-political and macro-sociological evidence on a global scale, published in the world’s leading peer-reviewed social science, ecological and public health journals, which seem to indicate that there are contradictions between unfettered globalization and unconstrained world economic openness and sustainable development and public health development. We suggest that there
Tausch, Arno
2013-08-01
This article looks at the long-term, structural determinants of environmental and public health performance in the world system. In multiple standard ordinary least squares (OLS) regression models, we tested the effects of 26 standard predictor variables, including the 'four freedoms' of goods, capital, labour and services, on the following indicators of sustainable development and public health: avoiding net trade of ecological footprint global hectare (gha) per person; avoiding high carbon emissions per million US dollars GDP; avoiding high CO2 per capita (gha/cap); avoiding high ecological footprint per capita; avoiding becoming victim of natural disasters; a good performance on the Environmental Performance Index (EPI); a good performance on the Happy Life Years (HLYs) scale; and a good performance on the Happy Planet Index (HPI). Our research showed that the apprehensions of quantitative research, critical of neo-liberal globalization, are fully vindicated by the significant negative environmental and public health effects of the foreign savings rate. High foreign savings are indeed a driver of global footprint, and are a blockade against a satisfactory HPI performance. The new international division of labour is one of the prime drivers of high CO2 per capita emissions. Multinational Corporation (MNC) penetration, the master variable of most quantitative dependency theories, blocks EPI and several other socially important processes. Worker remittances have a significant positive effect on the HPI, and HLYs. We re-analysed the solid macro-political and macro-sociological evidence on a global scale, published in the world's leading peer-reviewed social science, ecological and public health journals, which seem to indicate that there are contradictions between unfettered globalization and unconstrained world economic openness and sustainable development and public health development. We suggest that there seems to be a strong interaction between 'transnational
Analogical Reasoning in Geometry Education
Magdas, Ioana
2015-01-01
The analogical reasoning isn't used only in mathematics but also in everyday life. In this article we approach the analogical reasoning in Geometry Education. The novelty of this article is a classification of geometrical analogies by reasoning type and their exemplification. Our classification includes: analogies for understanding and setting a…
Normal forms in Poisson geometry
Marcut, I.T.
2013-01-01
The structure of Poisson manifolds is highly nontrivial even locally. The first important result in this direction is Conn's linearization theorem around fixed points. One of the main results of this thesis (Theorem 2) is a normal form theorem in Poisson geometry, which is the Poisson-geometric
Exploring Bundling Theory with Geometry
Eckalbar, John C.
2006-01-01
The author shows how instructors might successfully introduce students in principles and intermediate microeconomic theory classes to the topic of bundling (i.e., the selling of two or more goods as a package, rather than separately). It is surprising how much students can learn using only the tools of high school geometry. To be specific, one can…
Stochastic Modelling of River Geometry
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard; Schaarup-Jensen, K.
1996-01-01
Numerical hydrodynamic river models are used in a large number of applications to estimate critical events for rivers. These estimates are subject to a number of uncertainties. In this paper, the problem to evaluate these estimates using probabilistic methods is considered. Stochastic models for ...... for river geometries are formulated and a coupling between hydraulic computational methods and numerical reliability methods is presented....
Matter in toy dynamical geometries
Konopka, T.J.
2009-01-01
One of the objectives of theories describing quantum dynamical geometry is to compute expectation values of geometrical observables. The results of such computations can be affected by whether or not matter is taken into account. It is thus important to understand to what extent and to what effect
Ca??adas, Mar??a C.; Molina, Marta; Gallardo, Sandra; Mart??nez-Santaolalla, Manuel J.; Pe??as, Mar??a
2010-01-01
In this work we present an activity for High School students in which various mathematical concepts of plane and spatial geometry are involved. The final objective of the proposed tasks is constructing a particular polyhedron, the cube, by using a modality of origami called modular origami.
Granular flows in constrained geometries
Murthy, Tejas; Viswanathan, Koushik
Confined geometries are widespread in granular processing applications. The deformation and flow fields in such a geometry, with non-trivial boundary conditions, determine the resultant mechanical properties of the material (local porosity, density, residual stresses etc.). We present experimental studies of deformation and plastic flow of a prototypical granular medium in different nontrivial geometries- flat-punch compression, Couette-shear flow and a rigid body sliding past a granular half-space. These geometries represent simplified scaled-down versions of common industrial configurations such as compaction and dredging. The corresponding granular flows show a rich variety of flow features, representing the entire gamut of material types, from elastic solids (beam buckling) to fluids (vortex-formation, boundary layers) and even plastically deforming metals (dead material zone, pile-up). The effect of changing particle-level properties (e.g., shape, size, density) on the observed flows is also explicitly demonstrated. Non-smooth contact dynamics particle simulations are shown to reproduce some of the observed flow features quantitatively. These results showcase some central challenges facing continuum-scale constitutive theories for dynamic granular flows.
General Relativity: Geometry Meets Physics
Thomsen, Dietrick E.
1975-01-01
Observing the relationship of general relativity and the geometry of space-time, the author questions whether the rest of physics has geometrical explanations. As a partial answer he discusses current research on subatomic particles employing geometric transformations, and cites the existence of geometrical definitions of physical quantities such…
Learners engaging with transformation geometry
African Journals Online (AJOL)
participants engaged in investigative semi-structured interviews with the resear- chers. ... Keywords: analysis; conversions; transformation geometry; transformations; treatments .... semiotic systems of representation is not only to designate mathematical objects or to com- municate but also to ... Research design. We believe ...
Multivariable calculus and differential geometry
Walschap, Gerard
2015-01-01
This text is a modern in-depth study of the subject that includes all the material needed from linear algebra. It then goes on to investigate topics in differential geometry, such as manifolds in Euclidean space, curvature, and the generalization of the fundamental theorem of calculus known as Stokes' theorem.
College geometry a unified development
Kay, David C
2011-01-01
""The book is a comprehensive textbook on basic geometry. … Key features of the book include numerous figures and many problems, more than half of which come with hints or even complete solutions. Frequent historical comments add to making the reading a pleasant one.""-Michael Joswig, Zentralblatt MATH 1273
Mahaffey, Michael L.
One of a series of experimental units for children at the preschool level, this booklet deals with geometric concepts. A unit on volume and a unit on linear measurement are covered; for each unit a discussion of mathematical objectives, a list of materials needed, and a sequence of learning activities are provided. Directions are specified for the…
DEFF Research Database (Denmark)
Byg din egen boomerang, kast den, se den flyve, forstå hvorfor og hvordan den vender tilbage, og grib den. Det handler om opdriften på vingerne når du flyver, men det handler også og allermest om den mærkværdige gyroskop-effekt, du bruger til at holde balancen, når du kører på cykel. Vi vil bruge...
Discrete differential geometry. Consistency as integrability
Bobenko, Alexander I.; Suris, Yuri B.
2005-01-01
A new field of discrete differential geometry is presently emerging on the border between differential and discrete geometry. Whereas classical differential geometry investigates smooth geometric shapes (such as surfaces), and discrete geometry studies geometric shapes with finite number of elements (such as polyhedra), the discrete differential geometry aims at the development of discrete equivalents of notions and methods of smooth surface theory. Current interest in this field derives not ...
Kyte, Derek; Reeve, Bryce B; Efficace, Fabio; Haywood, Kirstie; Mercieca-Bebber, Rebecca; King, Madeleine T; Norquist, Josephine M; Lenderking, William R; Snyder, Claire; Ring, Lena; Velikova, Galina; Calvert, Melanie
2016-02-01
In 2014, the European Medicines Agency (EMA) released for comment a draft reflection paper on the use of patient-reported outcome (PRO) measures in oncology studies. A twelve-member International Society for Quality of Life Research (ISOQOL) taskforce was convened to coordinate the ISOQOL response. Twenty-one ISOQOL members provided detailed comments and suggestions on the paper: 81 % from academia and 19 % from industry. Taskforce members consolidated and further refined these comments and shared the recommendations with the wider ISOQOL membership. A final response was submitted to the EMA in November 2014. The impending publication of the EMA reflection paper presents a valuable opportunity for ISOQOL to comment on the current direction of EMA PRO guidance and strategy. The EMA paper, although focused on cancer, could serve as a model for using PROs in other conditions, as it provides a useful update surrounding some of the design issues common to all trial research including PRO endpoints. However, we believe there are a number of additional areas in need of greater consideration. The purpose of this commentary is therefore to highlight the strengths of this timely and potentially useful document, but also to outline areas that may warrant further discussion.
Numerically robust geometry engine for compound solid geometries
International Nuclear Information System (INIS)
Vlachoudis, V.; Sinuela-Pastor, D.
2013-01-01
Monte Carlo programs heavily rely on a fast and numerically robust solid geometry engines. However the success of solid modeling, depends on facilities for specifying and editing parameterized models through a user-friendly graphical front-end. Such a user interface has to be fast enough in order to be interactive for 2D and/or 3D displays, but at the same time numerically robust in order to display possible modeling errors at real time that could be critical for the simulation. The graphical user interface Flair for FLUKA currently employs such an engine where special emphasis has been given on being fast and numerically robust. The numerically robustness is achieved by a novel method of estimating the floating precision of the operations, which dynamically adapts all the decision operations accordingly. Moreover a predictive caching mechanism is ensuring that logical errors in the geometry description are found online, without compromising the processing time by checking all regions. (authors)
Geometry of illumination, luminance contrast, and gloss perception.
Leloup, Frédéric B; Pointer, Michael R; Dutré, Philip; Hanselaer, Peter
2010-09-01
The influence of both the geometry of illumination and luminance contrast on gloss perception has been examined using the method of paired comparison. Six achromatic glass samples having different lightness were illuminated by two light sources. Only one of these light sources was visible in reflection by the observer. By separate adjustment of the intensity of both light sources, the luminance of both the reflected image and the adjacent off-specular surroundings could be individually varied. It was found that visual gloss appraisal did not correlate with instrumentally measured specular gloss; however, psychometric contrast seemed to be a much better correlate. It has become clear that not only the sample surface characteristics determine gloss perception: the illumination geometry could be an even more important factor.
Bare AGN: an Unobscured View of the Innermost Accretion Geometry
Fink, M.; Dauser, T.; Beuchert, T.; Jeffreson, S.; Tawabutr, J.; Wilms, J.; Garcia, J.; Walton, D.
2017-10-01
In a systematic study of the relativistic reflection spectra and coronal properties for a sample of bare AGN we analyze high signal-to-noise spectra obtained with the XMM-Newton and NuSTAR observatories utilizing state-of-the-art reflection codes. Features of blurred reflection off an ionized accretion disk are modelled using different flavors of the relativistic ray-tracing code Relxill. We show that the more physically motivated and self-consistent lamp-post geometry is largely consistent with fits of broken power-law emissivity profiles. We provide good constraints on parameters describing the compact reprocessing corona, i.e., the reflection fraction and the lamp-post height. The latter are found to be prevalent within 1-10 r_{g}, while our models generally find close-to-maximal black hole spins. These results are discussed and compared with previous studies by Walton et al. (2013).
Geometry Design, Principles and Assembly of Micromotors
Directory of Open Access Journals (Sweden)
Huanpo Ning
2018-02-01
Full Text Available Discovery of bio-inspired, self-propelled and externally-powered nano-/micro-motors, rotors and engines (micromachines is considered a potentially revolutionary paradigm in nanoscience. Nature knows how to combine different elements together in a fluidic state for intelligent design of nano-/micro-machines, which operate by pumping, stirring, and diffusion of their internal components. Taking inspirations from nature, scientists endeavor to develop the best materials, geometries, and conditions for self-propelled motion, and to better understand their mechanisms of motion and interactions. Today, microfluidic technology offers considerable advantages for the next generation of biomimetic particles, droplets and capsules. This review summarizes recent achievements in the field of nano-/micromotors, and methods of their external control and collective behaviors, which may stimulate new ideas for a broad range of applications.
System Geometries and Transit/Eclipse Probabilities
Directory of Open Access Journals (Sweden)
Howard A.
2011-02-01
Full Text Available Transiting exoplanets provide access to data to study the mass-radius relation and internal structure of extrasolar planets. Long-period transiting planets allow insight into planetary environments similar to the Solar System where, in contrast to hot Jupiters, planets are not constantly exposed to the intense radiation of their parent stars. Observations of secondary eclipses additionally permit studies of exoplanet temperatures and large-scale exo-atmospheric properties. We show how transit and eclipse probabilities are related to planet-star system geometries, particularly for long-period, eccentric orbits. The resulting target selection and observational strategies represent the principal ingredients of our photometric survey of known radial-velocity planets with the aim of detecting transit signatures (TERMS.
Code subspaces for LLM geometries
Berenstein, David; Miller, Alexandra
2018-03-01
We consider effective field theory around classical background geometries with a gauge theory dual, specifically those in the class of LLM geometries. These are dual to half-BPS states of N= 4 SYM. We find that the language of code subspaces is natural for discussing the set of nearby states, which are built by acting with effective fields on these backgrounds. This work extends our previous work by going beyond the strict infinite N limit. We further discuss how one can extract the topology of the state beyond N→∞ and find that, as before, uncertainty and entanglement entropy calculations provide a useful tool to do so. Finally, we discuss obstructions to writing down a globally defined metric operator. We find that the answer depends on the choice of reference state that one starts with. Therefore, within this setup, there is ambiguity in trying to write an operator that describes the metric globally.
Euclidean distance geometry an introduction
Liberti, Leo
2017-01-01
This textbook, the first of its kind, presents the fundamentals of distance geometry: theory, useful methodologies for obtaining solutions, and real world applications. Concise proofs are given and step-by-step algorithms for solving fundamental problems efficiently and precisely are presented in Mathematica®, enabling the reader to experiment with concepts and methods as they are introduced. Descriptive graphics, examples, and problems, accompany the real gems of the text, namely the applications in visualization of graphs, localization of sensor networks, protein conformation from distance data, clock synchronization protocols, robotics, and control of unmanned underwater vehicles, to name several. Aimed at intermediate undergraduates, beginning graduate students, researchers, and practitioners, the reader with a basic knowledge of linear algebra will gain an understanding of the basic theories of distance geometry and why they work in real life.
The geometry of celestial mechanics
Geiges, Hansjörg
2016-01-01
Celestial mechanics is the branch of mathematical astronomy devoted to studying the motions of celestial bodies subject to the Newtonian law of gravitation. This mathematical introductory textbook reveals that even the most basic question in celestial mechanics, the Kepler problem, leads to a cornucopia of geometric concepts: conformal and projective transformations, spherical and hyperbolic geometry, notions of curvature, and the topology of geodesic flows. For advanced undergraduate and beginning graduate students, this book explores the geometric concepts underlying celestial mechanics and is an ideal companion for introductory courses. The focus on the history of geometric ideas makes it perfect supplementary reading for students in elementary geometry and topology. Numerous exercises, historical notes and an extensive bibliography provide all the contextual information required to gain a solid grounding in celestial mechanics.
Differential geometry and mathematical physics
Rudolph, Gerd
Starting from an undergraduate level, this book systematically develops the basics of • Calculus on manifolds, vector bundles, vector fields and differential forms, • Lie groups and Lie group actions, • Linear symplectic algebra and symplectic geometry, • Hamiltonian systems, symmetries and reduction, integrable systems and Hamilton-Jacobi theory. The topics listed under the first item are relevant for virtually all areas of mathematical physics. The second and third items constitute the link between abstract calculus and the theory of Hamiltonian systems. The last item provides an introduction to various aspects of this theory, including Morse families, the Maslov class and caustics. The book guides the reader from elementary differential geometry to advanced topics in the theory of Hamiltonian systems with the aim of making current research literature accessible. The style is that of a mathematical textbook,with full proofs given in the text or as exercises. The material is illustrated by numerous d...
Grassmannian geometry of scattering amplitudes
Arkani-Hamed, Nima; Cachazo, Freddy; Goncharov, Alexander; Postnikov, Alexander; Trnka, Jaroslav
2016-01-01
Outlining a revolutionary reformulation of the foundations of perturbative quantum field theory, this book is a self-contained and authoritative analysis of the application of this new formulation to the case of planar, maximally supersymmetric Yang–Mills theory. The book begins by deriving connections between scattering amplitudes and Grassmannian geometry from first principles before introducing novel physical and mathematical ideas in a systematic manner accessible to both physicists and mathematicians. The principle players in this process are on-shell functions which are closely related to certain sub-strata of Grassmannian manifolds called positroids - in terms of which the classification of on-shell functions and their relations becomes combinatorially manifest. This is an essential introduction to the geometry and combinatorics of the positroid stratification of the Grassmannian and an ideal text for advanced students and researchers working in the areas of field theory, high energy physics, and the...
Groups and Geometries : Siena Conference
Kantor, William; Lunardon, Guglielmo; Pasini, Antonio; Tamburini, Maria
1998-01-01
On September 1-7, 1996 a conference on Groups and Geometries took place in lovely Siena, Italy. It brought together experts and interested mathematicians from numerous countries. The scientific program centered around invited exposi tory lectures; there also were shorter research announcements, including talks by younger researchers. The conference concerned a broad range of topics in group theory and geometry, with emphasis on recent results and open problems. Special attention was drawn to the interplay between group-theoretic methods and geometric and combinatorial ones. Expanded versions of many of the talks appear in these Proceedings. This volume is intended to provide a stimulating collection of themes for a broad range of algebraists and geometers. Among those themes, represented within the conference or these Proceedings, are aspects of the following: 1. the classification of finite simple groups, 2. the structure and properties of groups of Lie type over finite and algebraically closed fields of f...
Needle decompositions in Riemannian geometry
Klartag, Bo'az
2017-01-01
The localization technique from convex geometry is generalized to the setting of Riemannian manifolds whose Ricci curvature is bounded from below. In a nutshell, the author's method is based on the following observation: When the Ricci curvature is non-negative, log-concave measures are obtained when conditioning the Riemannian volume measure with respect to a geodesic foliation that is orthogonal to the level sets of a Lipschitz function. The Monge mass transfer problem plays an important role in the author's analysis.
Systematics of IIB spinorial geometry
Gran, U.; Gutowski, J.; Papadopoulos, G.; Roest, D.
2005-01-01
We reduce the classification of all supersymmetric backgrounds of IIB supergravity to the evaluation of the Killing spinor equations and their integrability conditions, which contain the field equations, on five types of spinors. This extends the work of [hep-th/0503046] to IIB supergravity. We give the expressions of the Killing spinor equations on all five types of spinors. In this way, the Killing spinor equations become a linear system for the fluxes, geometry and spacetime derivatives of...
Geometry Dependence of Stellarator Turbulence
International Nuclear Information System (INIS)
Mynick, H.E.; Xanthopoulos, P.; Boozer, A.H.
2009-01-01
Using the nonlinear gyrokinetic code package GENE/GIST, we study the turbulent transport in a broad family of stellarator designs, to understand the geometry-dependence of the microturbulence. By using a set of flux tubes on a given flux surface, we construct a picture of the 2D structure of the microturbulence over that surface, and relate this to relevant geometric quantities, such as the curvature, local shear, and effective potential in the Schrodinger-like equation governing linear drift modes
Superbanana orbits in stellarator geometries
International Nuclear Information System (INIS)
Derr, J.A.; Shohet, J.L.
1979-04-01
The presence of superbanana orbit types localized to either the interior or the exterior of stellarators and torsatrons is numerically investigated for 3.5 MeV alpha particles. The absence of the interior superbanana in both geometries is found to be due to non-conservation of the action. Exterior superbananas are found in the stellarator only, as a consequence of the existence of closed helical magnetic wells. No superbananas of either type are found in the torsatron
Turtle geometry the Python way
Battle, S.
2014-01-01
An introduction to coding using Python’s on-screen ‘turtle’ that can be commanded with a few simple instructions including forward, backward, left and right. The turtle leaves a trace that can be used to draw geometric figures. This workshop is aimed at beginners of all ages. The aim is to learn a smattering of programming and a little bit of geometry in a fun way.
Topics in modern differential geometry
Verstraelen, Leopold
2017-01-01
A variety of introductory articles is provided on a wide range of topics, including variational problems on curves and surfaces with anisotropic curvature. Experts in the fields of Riemannian, Lorentzian and contact geometry present state-of-the-art reviews of their topics. The contributions are written on a graduate level and contain extended bibliographies. The ten chapters are the result of various doctoral courses which were held in 2009 and 2010 at universities in Leuven, Serbia, Romania and Spain.
Computational geometry for reactor applications
International Nuclear Information System (INIS)
Brown, F.B.; Bischoff, F.G.
1988-01-01
Monte Carlo codes for simulating particle transport involve three basic computational sections: a geometry package for locating particles and computing distances to regional boundaries, a physics package for analyzing interactions between particles and problem materials, and an editing package for determining event statistics and overall results. This paper describes the computational geometry methods in RACER, a vectorized Monte Carlo code used for reactor physics analysis, so that comparisons may be made with techniques used in other codes. The principal applications for RACER are eigenvalue calculations and power distributions associated with reactor core physics analysis. Successive batches of neutrons are run until convergence and acceptable confidence intervals are obtained, with typical problems involving >10 6 histories. As such, the development of computational geometry methods has emphasized two basic needs: a flexible but compact geometric representation that permits accurate modeling of reactor core details and efficient geometric computation to permit very large numbers of histories to be run. The current geometric capabilities meet these needs effectively, supporting a variety of very large and demanding applications
Number theory III Diophantine geometry
1991-01-01
From the reviews of the first printing of this book, published as Volume 60 of the Encyclopaedia of Mathematical Sciences: "Between number theory and geometry there have been several stimulating influences, and this book records of these enterprises. This author, who has been at the centre of such research for many years, is one of the best guides a reader can hope for. The book is full of beautiful results, open questions, stimulating conjectures and suggestions where to look for future developments. This volume bears witness of the broad scope of knowledge of the author, and the influence of several people who have commented on the manuscript before publication ... Although in the series of number theory, this volume is on diophantine geometry, and the reader will notice that algebraic geometry is present in every chapter. ... The style of the book is clear. Ideas are well explained, and the author helps the reader to pass by several technicalities. Reading and rereading this book I noticed that the topics ...
Riemannian geometry and geometric analysis
Jost, Jürgen
2017-01-01
This established reference work continues to provide its readers with a gateway to some of the most interesting developments in contemporary geometry. It offers insight into a wide range of topics, including fundamental concepts of Riemannian geometry, such as geodesics, connections and curvature; the basic models and tools of geometric analysis, such as harmonic functions, forms, mappings, eigenvalues, the Dirac operator and the heat flow method; as well as the most important variational principles of theoretical physics, such as Yang-Mills, Ginzburg-Landau or the nonlinear sigma model of quantum field theory. The present volume connects all these topics in a systematic geometric framework. At the same time, it equips the reader with the working tools of the field and enables her or him to delve into geometric research. The 7th edition has been systematically reorganized and updated. Almost no page has been left unchanged. It also includes new material, for instance on symplectic geometry, as well as the B...
Donaldson invariants in algebraic geometry
International Nuclear Information System (INIS)
Goettsche, L.
2000-01-01
In these lectures I want to give an introduction to the relation of Donaldson invariants with algebraic geometry: Donaldson invariants are differentiable invariants of smooth compact 4-manifolds X, defined via moduli spaces of anti-self-dual connections. If X is an algebraic surface, then these moduli spaces can for a suitable choice of the metric be identified with moduli spaces of stable vector bundles on X. This can be used to compute Donaldson invariants via methods of algebraic geometry and has led to a lot of activity on moduli spaces of vector bundles and coherent sheaves on algebraic surfaces. We will first recall the definition of the Donaldson invariants via gauge theory. Then we will show the relation between moduli spaces of anti-self-dual connections and moduli spaces of vector bundles on algebraic surfaces, and how this makes it possible to compute Donaldson invariants via algebraic geometry methods. Finally we concentrate on the case that the number b + of positive eigenvalues of the intersection form on the second homology of the 4-manifold is 1. In this case the Donaldson invariants depend on the metric (or in the algebraic geometric case on the polarization) via a system of walls and chambers. We will study the change of the invariants under wall-crossing, and use this in particular to compute the Donaldson invariants of rational algebraic surfaces. (author)
Aspects of differential geometry II
Gilkey, Peter
2015-01-01
Differential Geometry is a wide field. We have chosen to concentrate upon certain aspects that are appropriate for an introduction to the subject; we have not attempted an encyclopedic treatment. Book II deals with more advanced material than Book I and is aimed at the graduate level. Chapter 4 deals with additional topics in Riemannian geometry. Properties of real analytic curves given by a single ODE and of surfaces given by a pair of ODEs are studied, and the volume of geodesic balls is treated. An introduction to both holomorphic and Kähler geometry is given. In Chapter 5, the basic properties of de Rham cohomology are discussed, the Hodge Decomposition Theorem, Poincaré duality, and the Künneth formula are proved, and a brief introduction to the theory of characteristic classes is given. In Chapter 6, Lie groups and Lie algebras are dealt with. The exponential map, the classical groups, and geodesics in the context of a bi-invariant metric are discussed. The de Rham cohomology of compact Lie groups an...
Multiple-view, Multiple-selection Visualization of Simulation Geometry in CMS
International Nuclear Information System (INIS)
Bauerdick, L A T; Eulisse, G; Jones, C; McCauley, T; Osborne, I; Kovalskyi, D; Mrak Tadel, A; Tadel, M; Yagil, A
2012-01-01
Fireworks, the event-display program of CMS, was extended with an advanced geometry visualization package. ROOT's TGeo geometry is used as internal representation, shared among several geometry views. Each view is represented by a GUI list-tree widget, implemented as a flat vector to allow for fast searching, selection, and filtering by material type, node name, and shape type. Display of logical and physical volumes is supported. Color, transparency, and visibility flags can be modified for each node or for a selection of nodes. Further operations, like opening of a new view or changing of the root node, can be performed via a context menu. Node selection and graphical properties determined by the list-tree view can be visualized in any 3D graphics view of Fireworks. As each 3D view can display any number of geometry views, a user is free to combine different geometry-view selections within the same 3D view. Node-selection by proximity to a given point is possible. A visual clipping box can be set for each geometry view to limit geometry drawing into a specified region. Visualization of geometric overlaps, as detected by TGeo, is also supported. The geometry visualization package is used for detailed inspection and display of simulation geometry with or without the event data. It also serves as a tool for geometry debugging and inspection, facilitating development of geometries for CMS detector upgrades and for SLHC.
Algebraic Geometry and Number Theory Summer School
Sarıoğlu, Celal; Soulé, Christophe; Zeytin, Ayberk
2017-01-01
This lecture notes volume presents significant contributions from the “Algebraic Geometry and Number Theory” Summer School, held at Galatasaray University, Istanbul, June 2-13, 2014. It addresses subjects ranging from Arakelov geometry and Iwasawa theory to classical projective geometry, birational geometry and equivariant cohomology. Its main aim is to introduce these contemporary research topics to graduate students who plan to specialize in the area of algebraic geometry and/or number theory. All contributions combine main concepts and techniques with motivating examples and illustrative problems for the covered subjects. Naturally, the book will also be of interest to researchers working in algebraic geometry, number theory and related fields.
Geometry success in 20 minutes a day
LLC, LearningExpress
2014-01-01
Whether you're new to geometry or just looking for a refresher, Geometry Success in 20 Minutes a Day offers a 20-step lesson plan that provides quick and thorough instruction in practical, critical skills. Stripped of unnecessary math jargon but bursting with geometry essentials, Geometry Success in 20 Minutes a Day: Covers all vital geometry skills, from the basic building blocks of geometry to ratio, proportion, and similarity to trigonometry and beyond Provides hundreds of practice exercises in test format Applies geometr
Experimental and Theoretical Methods in Algebra, Geometry and Topology
Veys, Willem; Bridging Algebra, Geometry, and Topology
2014-01-01
Algebra, geometry and topology cover a variety of different, but intimately related research fields in modern mathematics. This book focuses on specific aspects of this interaction. The present volume contains refereed papers which were presented at the International Conference “Experimental and Theoretical Methods in Algebra, Geometry and Topology”, held in Eforie Nord (near Constanta), Romania, during 20-25 June 2013. The conference was devoted to the 60th anniversary of the distinguished Romanian mathematicians Alexandru Dimca and Ştefan Papadima. The selected papers consist of original research work and a survey paper. They are intended for a large audience, including researchers and graduate students interested in algebraic geometry, combinatorics, topology, hyperplane arrangements and commutative algebra. The papers are written by well-known experts from different fields of mathematics, affiliated to universities from all over the word, they cover a broad range of topics and explore the research f...
Network geometry with flavor: From complexity to quantum geometry
Bianconi, Ginestra; Rahmede, Christoph
2016-03-01
Network geometry is attracting increasing attention because it has a wide range of applications, ranging from data mining to routing protocols in the Internet. At the same time advances in the understanding of the geometrical properties of networks are essential for further progress in quantum gravity. In network geometry, simplicial complexes describing the interaction between two or more nodes play a special role. In fact these structures can be used to discretize a geometrical d -dimensional space, and for this reason they have already been widely used in quantum gravity. Here we introduce the network geometry with flavor s =-1 ,0 ,1 (NGF) describing simplicial complexes defined in arbitrary dimension d and evolving by a nonequilibrium dynamics. The NGF can generate discrete geometries of different natures, ranging from chains and higher-dimensional manifolds to scale-free networks with small-world properties, scale-free degree distribution, and nontrivial community structure. The NGF admits as limiting cases both the Bianconi-Barabási models for complex networks, the stochastic Apollonian network, and the recently introduced model for complex quantum network manifolds. The thermodynamic properties of NGF reveal that NGF obeys a generalized area law opening a new scenario for formulating its coarse-grained limit. The structure of NGF is strongly dependent on the dimensionality d . In d =1 NGFs grow complex networks for which the preferential attachment mechanism is necessary in order to obtain a scale-free degree distribution. Instead, for NGF with dimension d >1 it is not necessary to have an explicit preferential attachment rule to generate scale-free topologies. We also show that NGF admits a quantum mechanical description in terms of associated quantum network states. Quantum network states evolve by a Markovian dynamics and a quantum network state at time t encodes all possible NGF evolutions up to time t . Interestingly the NGF remains fully classical but
A climatology of visible surface reflectance spectra
International Nuclear Information System (INIS)
Zoogman, Peter; Liu, Xiong; Chance, Kelly; Sun, Qingsong; Schaaf, Crystal; Mahr, Tobias; Wagner, Thomas
2016-01-01
We present a high spectral resolution climatology of visible surface reflectance as a function of wavelength for use in satellite measurements of ozone and other atmospheric species. The Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument is planned to measure backscattered solar radiation in the 290–740 nm range, including the ultraviolet and visible Chappuis ozone bands. Observation in the weak Chappuis band takes advantage of the relative transparency of the atmosphere in the visible to achieve sensitivity to near-surface ozone. However, due to the weakness of the ozone absorption features this measurement is more sensitive to errors in visible surface reflectance, which is highly variable. We utilize reflectance measurements of individual plant, man-made, and other surface types to calculate the primary modes of variability of visible surface reflectance at a high spectral resolution, comparable to that of TEMPO (0.6 nm). Using the Moderate-resolution Imaging Spectroradiometer (MODIS) Bidirection Reflectance Distribution Function (BRDF)/albedo product and our derived primary modes we construct a high spatial resolution climatology of wavelength-dependent surface reflectance over all viewing scenes and geometries. The Global Ozone Monitoring Experiment–2 (GOME-2) Lambertian Equivalent Reflectance (LER) product provides complementary information over water and snow scenes. Preliminary results using this approach in multispectral ultraviolet+visible ozone retrievals from the GOME-2 instrument show significant improvement to the fitting residuals over vegetated scenes. - Highlights: • Our goals was visible surface reflectance for satellite trace gas measurements. • Captured the range of surface reflectance spectra through EOF analysis. • Used satellite surface reflectance products for each given scene to anchor EOFs. • Generated a climatology of time/geometry dependent surface reflectance spectra. • Demonstrated potential to
Kawashima, Natsumi; Hosono, Satsuki; Ishimaru, Ichiro
2016-05-01
We proposed the snapshot-type Fourier spectroscopic imaging for smartphone that was mentioned in 1st. report in this conference. For spectroscopic components analysis, such as non-invasive blood glucose sensors, the diffuse reflection lights from internal human skins are very weak for conventional hyperspectral cameras, such as AOTF (Acousto-Optic Tunable Filter) type. Furthermore, it is well known that the spectral absorption of mid-infrared lights or Raman spectroscopy especially in long wavelength region is effective to distinguish specific biomedical components quantitatively, such as glucose concentration. But the main issue was that photon energies of middle infrared lights and light intensities of Raman scattering are extremely weak. For improving sensitivity of our spectroscopic imager, the wide-field-stop & beam-expansion method was proposed. Our line spectroscopic imager introduced a single slit for field stop on the conjugate objective plane. Obviously to increase detected light intensities, the wider slit width of the field stop makes light intensities higher, regardless of deterioration of spatial resolutions. Because our method is based on wavefront-division interferometry, it becomes problems that the wider width of single slit makes the diffraction angle narrower. This means that the narrower diameter of collimated objective beams deteriorates visibilities of interferograms. By installing the relative inclined phaseshifter onto optical Fourier transform plane of infinity corrected optical systems, the collimated half flux of objective beams derived from single-bright points on objective surface penetrate through the wedge prism and the cuboid glass respectively. These two beams interfere each other and form the infererogram as spatial fringe patterns. Thus, we installed concave-cylindrical lens between the wider slit and objective lens as a beam expander. We successfully obtained the spectroscopic characters of hemoglobin from reflected lights from
A Whirlwind Tour of Computational Geometry.
Graham, Ron; Yao, Frances
1990-01-01
Described is computational geometry which used concepts and results from classical geometry, topology, combinatorics, as well as standard algorithmic techniques such as sorting and searching, graph manipulations, and linear programing. Also included are special techniques and paradigms. (KR)
Optimizing solar-cell grid geometry
Crossley, A. P.
1969-01-01
Trade-off analysis and mathematical expressions calculate optimum grid geometry in terms of various cell parameters. Determination of the grid geometry provides proper balance between grid resistance and cell output to optimize the energy conversion process.
Streaked x-ray spectrometer having a discrete selection of Bragg geometries for Omega
Energy Technology Data Exchange (ETDEWEB)
Millecchia, M.; Regan, S. P.; Bahr, R. E.; Romanofsky, M.; Sorce, C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299 (United States)
2012-10-15
The streaked x-ray spectrometer (SXS) is used with streak cameras [D. H. Kalantar, P. M. Bell, R. L. Costa, B. A. Hammel, O. L. Landen, T. J. Orzechowski, J. D. Hares, and A. K. L. Dymoke-Bradshaw, in 22nd International Congress on High-Speed Photography and Photonics, edited by D. L. Paisley and A. M. Frank (SPIE, Bellingham, WA, 1997), Vol. 2869, p. 680] positioned with a ten-inch manipulator on OMEGA [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] and OMEGA EP [L. J. Waxer et al., Presented at CLEO/QELS 2008, San Jose, CA, 4-9 May 2008 (Paper JThB1)] for time-resolved, x-ray spectroscopy of laser-produced plasmas in the 1.4- to 20-keV photon-energy range. These experiments require measuring a portion of this photon-energy range to monitor a particular emission or absorption feature of interest. The SXS relies on a pinned mechanical reference system to create a discrete set of Bragg reflection geometries for a variety of crystals. A wide selection of spectral windows is achieved accurately and efficiently using this technique. It replaces the previous spectrometer designs that had a continuous Bragg angle adjustment and required a tedious alignment calibration procedure. The number of spectral windows needed for the SXS was determined by studying the spectral ranges selected by OMEGA users over the last decade. These selections are easily configured in the SXS using one of the 25 discrete Bragg reflection geometries and one of the six types of Bragg crystals, including two curved crystals.