Directory of Open Access Journals (Sweden)
Robitaille P.-M.
2009-10-01
Full Text Available Through the reevaluation of Kirchhoff's law (Robitaille P.M.L. IEEE Trans. Plasma Sci., 2003, v.31(6, 1263-1267, Planck's blackbody equation (Planck M. Ann. der Physik, 1901, v.4, 553-356 loses its universal significance and becomes restricted to perfect absorbers. Consequently, the proper application of Planck's radiation law involves the study of solid opaque objects, typically made from graphite, soot, and carbon black. The extension of this equation to other materials may yield apparent temperatures, which do not have any physical meaning relative to the usual temperature scales. Real temperatures are exclusively obtained from objects which are known solids, or which are enclosed within, or in equilibrium with, a perfect absorber. For this reason, the currently accepted temperature of the microwave background must be viewed as an apparent temperature. Rectifying this situation, while respecting real temperatures, involves a reexamination of Boltzman's constant. In so doing, the latter is deprived of its universal nature and, in fact, acts as a temperature dependent variable. In its revised form, Planck's equation becomes temperature insensitive near 300K, when applied to the microwave background.
Directory of Open Access Journals (Sweden)
Robitaille P.-M.
2009-10-01
Full Text Available Through the reevaluation of Kirchhoff’s law (Robitaille P. M. L. IEEE Trans. Plasma Sci. , 2003, v. 31(6, 1263–1267, Planck’s blackbody equation (Planck M. Ann. der Physik , 1901, v. 4, 553–356 loses its universal significance and becomes restricted to perfect absorbers. Consequently, the proper application of Planck’s radiation law in- volves the study of solid opaque objects, typically made from graphite, soot, and carbon black. The extension of this equation to other materials may yield apparent tempera- tures, which do not have any physical meaning relative to the usual temperature scales. Real temperatures are exclusively obtained from objects which are known solids, or which are enclosed within, or in equilibrium with, a perfect absorber. For this reason, the currently accepted temperature of the microwave background must be viewed as an apparent temperature. Rectifying this situation, while respecting real temperatures, involves a reexamination of Boltzman’s constant. In so doing, the latter is deprived of its universal nature and, in fact, acts as a temperature dependent variable. In its revised form, Planck’s equation becomes temperature insensitive near 300 K, when applied to the microwave background.
Interacting universes and the cosmological constant
Energy Technology Data Exchange (ETDEWEB)
Alonso-Serrano, A. [Centro de Física “Miguel Catalán”, Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 121, 28006 Madrid (Spain); Estación Ecológica de Biocosmología, Pedro de Alvarado 14, 06411 Medellín (Spain); Bastos, C. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal); Bertolami, O. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal); Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Robles-Pérez, S., E-mail: salvarp@imaff.cfmac.csic.es [Centro de Física “Miguel Catalán”, Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 121, 28006 Madrid (Spain); Estación Ecológica de Biocosmología, Pedro de Alvarado 14, 06411 Medellín (Spain); Física Teórica, Universidad del País Vasco, Apartado 644, 48080 Bilbao (Spain)
2013-02-12
In this Letter it is studied the effects that an interaction scheme among universes can have in the values of their cosmological constants. In the case of two interacting universes, the value of the cosmological constant of one of the universes becomes very close to zero at the expense of an increasing value of the cosmological constant of the partner universe. In the more general case of a chain of N interacting universes with periodic boundary conditions, the spectrum of the Hamiltonian splits into a large number of levels, each of them associated with a particular value of the cosmological constant, that can be occupied by single universes revealing a collective behavior that plainly shows that the multiverse is much more than the mere sum of its parts.
Our Universe from the cosmological constant
Energy Technology Data Exchange (ETDEWEB)
Barrau, Aurélien; Linsefors, Linda, E-mail: Aurelien.Barrau@cern.ch, E-mail: linda.linsefors@lpsc.in2p3.fr [Laboratoire de Physique Subatomique et de Cosmologie, Université Grenoble-Alpes, CNRS-IN2P3, 53, avenue des Martyrs, 38026 Grenoble Cedex (France)
2014-12-01
The issue of the origin of the Universe and of its contents is addressed in the framework of bouncing cosmologies, as described for example by loop quantum gravity. If the current acceleration is due to a true cosmological constant, this constant is naturally conserved through the bounce and the Universe should also be in a (contracting) de Sitter phase in the remote past. We investigate here the possibility that the de Sitter temperature in the contracting branch fills the Universe with radiation that causes the bounce and the subsequent inflation and reheating. We also consider the possibility that this gives rise to a cyclic model of the Universe and suggest some possible tests.
Pattern Recognition of Universal Mathematical Constants in Acheulean Biface Formats
National Research Council Canada - National Science Library
Alan Edward Cannell
2015-01-01
...) and examine the presence of universal mathematical constants. A probabilistic analysis suggests that the repeated use of the numbers 2, Pi and Phi and the relationship between them could not have been produced by chance. These relationships appear to be constant over very long time periods and are still used today in modern gemstone design.
Measuring the gravitational constant in a university laboratory
Energy Technology Data Exchange (ETDEWEB)
Stepanov, Nikolai S; Shisharin, Alexandr V [N.I. Lobachevskii Nizhnii Novgorod State University, Nizhnii Novgorod (Russian Federation)
2002-05-31
A setup for measuring gravitational constant in a university laboratory is described. The setup includes a torsion pendulum which swings under the action of gravitational attraction from test masses whose positions are made to change periodically in phase with pendulum oscillations by a special device. The gravity constant is calculated from the amplitude of steady-state oscillations. The experimental and calculation procedure is described and measurement errors are estimated. (methodological notes)
The five dimensional universal hypermultiplet and the cosmological constant problem
Canestaro, Charles A.; Emam, Moataz H.
2013-11-01
We model the universe as a 3-brane embedded in five dimensional spacetime with N=2 supersymmetry. The presence of the scalar fields of the universal hypermultiplet in the bulk results in a positive pressure effectively reducing the value of the cosmological constant and thereby providing a possible answer as to why the measured value of the cosmological constant is many orders of magnitude smaller than predicted from the vacuum energy. The solution allows for any number of parallel branes to exist and relates their cosmological constants (as well as matter densities and radiation pressures) to the value of the dilaton in the extra dimension. The results we find can be thought of as first order approximations, satisfying supersymmetry breaking and the Bogomol'nyi-Prasad-Sommerfield (BPS) conditions in the bulk only.
Cosmic Explosions, Life in the Universe, and the Cosmological Constant.
Piran, Tsvi; Jimenez, Raul; Cuesta, Antonio J; Simpson, Fergus; Verde, Licia
2016-02-26
Gamma-ray bursts (GRBs) are copious sources of gamma rays whose interaction with a planetary atmosphere can pose a threat to complex life. Using recent determinations of their rate and probability of causing massive extinction, we explore what types of universes are most likely to harbor advanced forms of life. We use cosmological N-body simulations to determine at what time and for what value of the cosmological constant (Λ) the chances of life being unaffected by cosmic explosions are maximized. Life survival to GRBs favors Lambda-dominated universes. Within a cold dark matter model with a cosmological constant, the likelihood of life survival to GRBs is governed by the value of Λ and the age of the Universe. We find that we seem to live in a favorable point in this parameter space that minimizes the exposure to cosmic explosions, yet maximizes the number of main sequence (hydrogen-burning) stars around which advanced life forms can exist.
How universe evolves with cosmological and gravitational constants
Directory of Open Access Journals (Sweden)
She-Sheng Xue
2015-08-01
Full Text Available With a basic varying space–time cutoff ℓ˜, we study a regularized and quantized Einstein–Cartan gravitational field theory and its domains of ultraviolet-unstable fixed point gir≳0 and ultraviolet-stable fixed point guv≈4/3 of the gravitational gauge coupling g=(4/3G/GNewton. Because the fundamental operators of quantum gravitational field theory are dimension-2 area operators, the cosmological constant is inversely proportional to the squared correlation length Λ∝ξ−2. The correlation length ξ characterizes an infrared size of a causally correlate patch of the universe. The cosmological constant Λ and the gravitational constant G are related by a generalized Bianchi identity. As the basic space–time cutoff ℓ˜ decreases and approaches to the Planck length ℓpl, the universe undergoes inflation in the domain of the ultraviolet-unstable fixed point gir, then evolves to the low-redshift universe in the domain of ultraviolet-stable fixed point guv. We give the quantitative description of the low-redshift universe in the scaling-invariant domain of the ultraviolet-stable fixed point guv, and its deviation from the ΛCDM can be examined by low-redshift (z≲1 cosmological observations, such as supernova Type Ia.
Primordial perturbations in a rainbow universe with running Newton constant
Brighenti, Francesco; Gubitosi, Giulia; Magueijo, Joao
2017-03-01
We compute the spectral index of primordial perturbations in a rainbow universe. We allow the Newton constant G to run at (super-) Planckian energies and we consider both vacuum and thermal perturbations. If the rainbow metric is the one associated to a generalized Horava-Lifshitz dispersion relation, we find that only when G tends asymptotically to 0 can one match the observed value of the spectral index and solve the horizon problem, both for vacuum and thermal perturbations. For vacuum fluctuations the observational constraints imply that the primordial universe expansion can be both accelerating or decelerating, while in the case of thermal perturbations only decelerating expansion is allowed.
Energy and Economic Losses Due to Constant Power Outages in ...
African Journals Online (AJOL)
The results of the analysis also show that the economic losses associated with self-generation of electricity is high. Compared to an ... the use of generators. These will also assist energy policy makers and governments at all levels in developing highly applicable and productive planning for future energy policies in Nigeria.
A many-universe theory of the cosmological constant or warm universe in the googolplexus
Cline, James M.
1990-11-01
We reexamine the discouraging conclusion of Fischler, Klebanov, Polchinski and Susskind that second quantization of the Wheeler-DeWitt equation leads to the production of only cold and empty universes with vanishing cosmological constant Λ. We argue that if gravity is coupled to a scalar field with a suitable inflationary potential, the number of created universes which have at least one warm, inhabitable region by late times is exponentially peaked at Λ = 0. This appears to be a viable solution to the cosmological constant problem, invoking the weak anthropic principle in a natural way.
Universal Loss Dynamics in a Unitary Bose Gas
Directory of Open Access Journals (Sweden)
Ulrich Eismann
2016-05-01
Full Text Available The low-temperature unitary Bose gas is a fundamental paradigm in few-body and many-body physics, attracting wide theoretical and experimental interest. Here, we present experiments performed with unitary ^{133}Cs and ^{7}Li atoms in two different setups, which enable quantitative comparison of the three-body recombination rate in the low-temperature domain. We develop a theoretical model that describes the dynamic competition between two-body evaporation and three-body recombination in a harmonically trapped unitary atomic gas above the condensation temperature. We identify a universal “magic” trap depth where, within some parameter range, evaporative cooling is balanced by recombination heating and the gas temperature stays constant. Our model is developed for the usual three-dimensional evaporation regime as well as the two-dimensional evaporation case, and it fully supports our experimental findings. Combined ^{133}Cs and ^{7}Li experimental data allow investigations of loss dynamics over 2 orders of magnitude in temperature and 4 orders of magnitude in three-body loss rate. We confirm the 1/T^{2} temperature universality law. In particular, we measure, for the first time, the Efimov inelasticity parameter η_{*}=0.098(7 for the 47.8-G d-wave Feshbach resonance in ^{133}Cs. Our result supports the universal loss dynamics of trapped unitary Bose gases up to a single parameter η_{*}.
Universality of thermodynamic constants governing biological growth rates.
Corkrey, Ross; Olley, June; Ratkowsky, David; McMeekin, Tom; Ross, Tom
2012-01-01
Mathematical models exist that quantify the effect of temperature on poikilotherm growth rate. One family of such models assumes a single rate-limiting 'master reaction' using terms describing the temperature-dependent denaturation of the reaction's enzyme. We consider whether such a model can describe growth in each domain of life. A new model based on this assumption and using a hierarchical Bayesian approach fits simultaneously 95 data sets for temperature-related growth rates of diverse microorganisms from all three domains of life, Bacteria, Archaea and Eukarya. Remarkably, the model produces credible estimates of fundamental thermodynamic parameters describing protein thermal stability predicted over 20 years ago. The analysis lends support to the concept of universal thermodynamic limits to microbial growth rate dictated by protein thermal stability that in turn govern biological rates. This suggests that the thermal stability of proteins is a unifying property in the evolution and adaptation of life on earth. The fundamental nature of this conclusion has importance for many fields of study including microbiology, protein chemistry, thermal biology, and ecological theory including, for example, the influence of the vast microbial biomass and activity in the biosphere that is poorly described in current climate models.
Universality of thermodynamic constants governing biological growth rates.
Directory of Open Access Journals (Sweden)
Ross Corkrey
Full Text Available BACKGROUND: Mathematical models exist that quantify the effect of temperature on poikilotherm growth rate. One family of such models assumes a single rate-limiting 'master reaction' using terms describing the temperature-dependent denaturation of the reaction's enzyme. We consider whether such a model can describe growth in each domain of life. METHODOLOGY/PRINCIPAL FINDINGS: A new model based on this assumption and using a hierarchical Bayesian approach fits simultaneously 95 data sets for temperature-related growth rates of diverse microorganisms from all three domains of life, Bacteria, Archaea and Eukarya. Remarkably, the model produces credible estimates of fundamental thermodynamic parameters describing protein thermal stability predicted over 20 years ago. CONCLUSIONS/SIGNIFICANCE: The analysis lends support to the concept of universal thermodynamic limits to microbial growth rate dictated by protein thermal stability that in turn govern biological rates. This suggests that the thermal stability of proteins is a unifying property in the evolution and adaptation of life on earth. The fundamental nature of this conclusion has importance for many fields of study including microbiology, protein chemistry, thermal biology, and ecological theory including, for example, the influence of the vast microbial biomass and activity in the biosphere that is poorly described in current climate models.
Normalized General Relativity: Non-closed Universe and Zero Cosmological Constant
Davidson, Aharon
2014-01-01
We discuss the cosmological constant problem, at the minisuperspace level, within the framework of the so-called normalized general relativity (NGR). We prove that the Universe cannot be closed, and reassure that the accompanying cosmological constant $\\Lambda$ generically vanishes, at least classically. The theory does allow, however, for a special class of $\\Lambda \
Soil loss prediction using universal soil loss equation (USLE ...
African Journals Online (AJOL)
USER
2010-06-14
Jun 14, 2010 ... Land degradation and soil loss is a global event. Human induced pressures on the natural ecosystems are still in progress as well as conservation efforts. The need for sufficient knowledge and data for decision makers is obvious hence the present study was carried out. The study area, the Ağlasun district ...
Large scale geometry and evolution of a universe with radiation pressure and cosmological constant
Coquereaux, Robert; Coquereaux, Robert; Grossmann, Alex
2000-01-01
In view of new experimental results that strongly suggest a non-zero cosmological constant, it becomes interesting to revisit the Friedmann-Lemaitre model of evolution of a universe with cosmological constant and radiation pressure. In this paper, we discuss the explicit solutions for that model, and perform numerical explorations for reasonable values of cosmological parameters. We also analyse the behaviour of redshifts in such models and the description of ``very large scale geometrical features'' when analysed by distant observers.
Ground State of the Universe and the Cosmological Constant. A Nonperturbative Analysis.
Husain, Viqar; Qureshi, Babar
2016-02-12
The physical Hamiltonian of a gravity-matter system depends on the choice of time, with the vacuum naturally identified as its ground state. We study the expanding Universe with scalar field in the volume time gauge. We show that the vacuum energy density computed from the resulting Hamiltonian is a nonlinear function of the cosmological constant and time. This result provides a new perspective on the relation between time, the cosmological constant, and vacuum energy.
Cho, Guangsup; Shin, Myeong-Ju; Jeong, Jong-Mun; Kim, Jung-Hyun; Hong, Byoung-Hee; Koo, Je-Huan; Kim, YunKi; Choi, Eun-Ha; Fechner, Joerg; Letz, Martin; Ott, Franz
2007-12-01
A glass tube of aluminosilicate glass, with high dielectric constant K ˜6.0 and low dielectric loss tan δ˜8.0×10-4, was investigated for the external electrode fluorescent lamps (EEFLs) of a dielectric barrier discharge. Compared with conventional EEFLs made out of borosilicate glass tubes with K˜(4.9-5.3) and tan δ˜(2.3-2.4)×10-3, the efficiency of the aluminosilicate EEFL increases by 15%-25% even at high luminance above 20 000 cd/m2 and the pinhole stability of the aluminosilicate EEFL also improves remarkably. In a soda-lime glass EEFL with a high dielectric loss tan δ˜7.0×10-3, the luminance and pinhole stability deteriorate even with a high dielectric constant K ˜7.2 at room temperature, because the value of tan δ escalates as the temperature on the external electrode increases due to the dielectric heat dissipation.
Tian, Ming; Zhang, Jing; Zhang, Liqun; Liu, Suting; Zan, Xiaoqing; Nishi, Toshio; Ning, Nanying
2014-09-15
A dielectric composite with high dielectric constant, low dielectric loss and low percolation threshold was prepared by using the combined strategy of encapsulating of graphene oxide nanosheets (GONS) on carboxylated nitrile rubber (XNBR) latex particles and the in situ thermal reduction in GONS at a moderate temperature. The encapsulation of GONS on XNBR latex particles was mainly realized via the hydrogen bonding interactions between GONS and XNBR during latex mixing. A segregated graphene network was obtained at a low content of thermally reduced graphene (TRG), resulting in a low percolation threshold (0.25 vol.%). The dielectric constant at 100 Hz obviously increased from 23 for pure XNBR to 2211 and 5542 for the composite with 0.5 vol.% and 0.75 vol.% of TRG, respectively. The dielectric loss of the composites retained at a low value (less than 1.5). Meanwhile, the elastic modulus only slightly increased with the presence of 0.1-0.5 vol.% of TRG, keeping the good flexibility of the dielectric composites. This study provides a simple, low-cost and effective method to prepare high performance dielectric composites, facilitating the wide application of dielectric materials. Copyright © 2014 Elsevier Inc. All rights reserved.
Chakraborty, Writambhara; Debnath, Ujjal
2008-02-01
In this paper we have considered the Universe to be filled with Modified Gas and the Cosmological Constant Λ to be time-dependent with or without the Gravitational Constant G to be time-dependent. We have considered various phenomenological models for Λ, viz., Λ∝ρ,Λ∝dot{a}2/a2 and Λ∝ddot{a}/a . Using these models it is possible to show the accelerated expansion of the Universe at the present epoch. Also we have shown the natures of G and Λ over the total age of the Universe. Using the statefinder parameters we have shown the diagrammatical representation of the evolution of the Universe starting from radiation era to ΛCDM model.
Weight-loss practices among university students in Mexico.
Méndez-Hernández, Pablo; Dosamantes-Carrasco, Darina; Lamure, Michel; López-Loyo, Perla; Hernández-Palafox, Corín; Pineda-Pérez, Dayana; Flores, Yvonne; Salmerón, Jorge
2010-06-01
To evaluate the prevalence of weight-loss practices among university students from Tlaxcala, Mexico. A cross-sectional study of 2,651 university students was conducted. Logistic regression tests were used to estimate the probability of students trying to lose weight and successfully achieving weight loss. Nearly 40% of students attempted to lose weight, though only about 7% lost more than 10% of their body weight and maintained this weight loss during the time of the study. The methods used most were exercise and dieting, and those who dieted were more successful at losing weight. The high prevalence of weight-loss attempts and the poor outcomes with these weight-loss methods among this sample of university students is a public health concern. Universities should provide students with healthy weight-control approaches, which include offering information about healthier lifestyles, access to healthy food and opportunities to be physically active.
Saw, Vee-Liem
2016-01-01
We derive the asymptotic solutions for vacuum spacetimes with non-zero cosmological constant $\\Lambda$, using the Newman-Penrose formalism. Our approach is based exclusively on the physical spacetime, i.e. no reference of conformal rescaling nor conformal spacetime is made, at least not explicitly. By investigating the Schwarzschild-de Sitter spacetime in spherical coordinates, we subsequently stipulate the fall-offs of the null tetrad and spin coefficients for asymptotically de Sitter spacetimes such that the terms which would give rise to the Bondi mass-loss due to energy carried by gravitational radiation (i.e. involving $\\sigma^o$) must be non-zero. After solving the vacuum Newman-Penrose equations asymptotically, we obtain the Bondi mass-loss formula by integrating the Bianchi identity involving $D'\\Psi_2$ over a compact 2-surface on $\\mathcal{I}$. Whilst our original intention was to study asymptotically de Sitter spacetimes, the use of spherical coordinates implies that this readily applies for $\\Lambd...
Carboxylic acid functional group analysis using constant neutral loss scanning-mass spectrometry
Energy Technology Data Exchange (ETDEWEB)
Dron, Julien [Laboratoire de Chimie et Environnement, Marseille Universites (case 29), 3 place Victor Hugo, 13331 Marseille Cedex 3 (France)], E-mail: julien.dron@up.univ-mrs.fr; Eyglunent, Gregory; Temime-Roussel, Brice; Marchand, Nicolas; Wortham, Henri [Laboratoire de Chimie et Environnement, Marseille Universites (case 29), 3 place Victor Hugo, 13331 Marseille Cedex 3 (France)
2007-12-12
The present study describes the development of a new analytical technique for the functional group determination of the carboxylic moiety using atmospheric pressure chemical ionization-mass spectrometry (APCI-MS/MS) operated in the constant neutral loss scanning (CNLS) mode. Carboxylic groups were first derivatized into their corresponding methyl esters by reacting with BF{sub 3}/methanol mix and the reaction mixture was then directly injected into the APCI chamber. The loss of methanol (m/z = 32 amu) resulting from the fragmentation of the protonated methyl esters was then monitored. Applying this method together with a statistical approach to reference mixtures containing 31 different carboxylic acids at randomly calculated concentrations demonstrated its suitability for quantitative functional group measurements with relative standard deviations below 15% and a detection limit of 0.005 mmol L{sup -1}. Its applicability to environmental matrices was also shown through the determination of carboxylic acid concentrations inside atmospheric aerosol samples. To the best of our knowledge, it is the first time that the tandem mass spectrometry was successfully applied to functional group analysis, offering great perspectives in the characterization of complex mixtures which are prevailing in the field of environmental analysis as well as in the understanding of the chemical processes occurring in these matrices.
Running vacuum in the Universe and the time variation of the fundamental constants of Nature
Energy Technology Data Exchange (ETDEWEB)
Fritzsch, Harald [Nanyang Technological University, Institute for Advanced Study, Singapore (Singapore); Universitaet Muenchen, Physik-Department, Munich (Germany); Sola, Joan [Nanyang Technological University, Institute for Advanced Study, Singapore (Singapore); Universitat de Barcelona, Departament de Fisica Quantica i Astrofisica, Barcelona, Catalonia (Spain); Universitat de Barcelona (ICCUB), Institute of Cosmos Sciences, Barcelona, Catalonia (Spain); Nunes, Rafael C. [Universidade Federal de Juiz de Fora, Dept. de Fisica, Juiz de Fora, MG (Brazil)
2017-03-15
We compute the time variation of the fundamental constants (such as the ratio of the proton mass to the electron mass, the strong coupling constant, the fine-structure constant and Newton's constant) within the context of the so-called running vacuum models (RVMs) of the cosmic evolution. Recently, compelling evidence has been provided that these models are able to fit the main cosmological data (SNIa+BAO+H(z)+LSS+BBN+CMB) significantly better than the concordance ΛCDM model. Specifically, the vacuum parameters of the RVM (i.e. those responsible for the dynamics of the vacuum energy) prove to be nonzero at a confidence level >or similar 3σ. Here we use such remarkable status of the RVMs to make definite predictions on the cosmic time variation of the fundamental constants. It turns out that the predicted variations are close to the present observational limits. Furthermore, we find that the time evolution of the dark matter particle masses should be crucially involved in the total mass variation of our Universe. A positive measurement of this kind of effects could be interpreted as strong support to the ''micro-macro connection'' (viz. the dynamical feedback between the evolution of the cosmological parameters and the time variation of the fundamental constants of the microscopic world), previously proposed by two of us (HF and JS). (orig.)
Running vacuum in the Universe and the time variation of the fundamental constants of Nature
Fritzsch, Harald; Solà, Joan; Nunes, Rafael C.
2017-03-01
We compute the time variation of the fundamental constants (such as the ratio of the proton mass to the electron mass, the strong coupling constant, the fine-structure constant and Newton's constant) within the context of the so-called running vacuum models (RVMs) of the cosmic evolution. Recently, compelling evidence has been provided that these models are able to fit the main cosmological data (SNIa+BAO+H(z)+LSS+BBN+CMB) significantly better than the concordance Λ CDM model. Specifically, the vacuum parameters of the RVM (i.e. those responsible for the dynamics of the vacuum energy) prove to be nonzero at a confidence level ≳ 3σ . Here we use such remarkable status of the RVMs to make definite predictions on the cosmic time variation of the fundamental constants. It turns out that the predicted variations are close to the present observational limits. Furthermore, we find that the time evolution of the dark matter particle masses should be crucially involved in the total mass variation of our Universe. A positive measurement of this kind of effects could be interpreted as strong support to the "micro-macro connection" (viz. the dynamical feedback between the evolution of the cosmological parameters and the time variation of the fundamental constants of the microscopic world), previously proposed by two of us (HF and JS).
DEFF Research Database (Denmark)
Damgård, Ivan Bjerre; Nielsen, Jesper Buus
2002-01-01
Canetti and Fischlin have recently proposed the security notion universal composability for commitment schemes and provided two examples. This new notion is very strong. It guarantees that security is maintained even when an unbounded number of copies of the scheme are running concurrently, also ...... versions. These are the rst schemes to show that constant expansion factor, perfect hiding, and perfect binding can be obtained for universally composable commitments.......Canetti and Fischlin have recently proposed the security notion universal composability for commitment schemes and provided two examples. This new notion is very strong. It guarantees that security is maintained even when an unbounded number of copies of the scheme are running concurrently, also...... it guarantees non-malleability, resilience to selective decommitment, and security against adaptive adversaries. Both of their schemes uses (k) bits to commit to one bit and can be based on the existence of trapdoor commitments and non-malleable encryption. We present new universally composable commitment...
The varying cosmological constant: A new approximation to the Friedmann equations and universe model
Öztaş, Ahmet M.; Dil, Emre; Smith, Michael L.
2018-01-01
We investigate the time-dependent nature of the cosmological constant, Λ, of the Einstein Field Equation (EFE). Beginning with the Einstein-Hilbert action as our fundamental principle we develop a modified version of the EFE allowing the value of Λ to vary as a function of time, Λ(t), indirectly, for an expanding universe. We follow the evolving Λ presuming 4-dimensional spacetime and a flat universe geometry and present derivations of Λ(t) as functions of the Hubble constant, matter density and volume changes which can be traced back to the radiation epoch. The models are more detailed descriptions of the Λ dependence on cosmological factors than previous, allowing calculations of the important parameters, Ωm and Ωr, to deep lookback times. Since we derive these without the need for extra dimensions or other special conditions our derivations are useful for model evaluation with astronomical data. This should aid resolution of several difficult problems of astronomy such as the best value for the Hubble constant at present and at recombination.
Energy Technology Data Exchange (ETDEWEB)
Gorokhovski, M A [Laboratoire de Mecanique des Fluides et d' Acoustique, CNRS - Ecole Centrale de Lyon - INSA Lyon - Universite Claude Bernard Lyon 1, 36 Avenue Guy de Collongue, 69134 Ecully Cedex (France); Saveliev, V L [Institut of Ionosphere, Kamenskoe Plato, 050020 Almaty (Kazakhstan)], E-mail: mikhael.gorokhovski@ec-lyon.fr, E-mail: saveliev@topmail.kz
2008-04-21
This paper analyses statistical universalities that arise over time during constant frequency fragmentation under scaling symmetry. The explicit expression of particle-size distribution obtained from the evolution kinetic equation shows that, with increasing time, the initial distribution tends to the ultimate steady-state delta function through at least two intermediate universal asymptotics. The earlier asymptotic is the well-known log-normal distribution of Kolmogorov (1941 Dokl. Akad. Nauk. SSSR 31 99-101). This distribution is the first universality and has two parameters: the first and the second logarithmic moments of the fragmentation intensity spectrum. The later asymptotic is a power function (stronger universality) with a single parameter that is given by the ratio of the first two logarithmic moments. At large times, the first universality implies that the evolution equation can be reduced exactly to the Fokker-Planck equation instead of making the widely used but inconsistent assumption about the smallness of higher than second order moments. At even larger times, the second universality shows evolution towards a fractal state with dimension identified as a measure of the fracture resistance of the medium.
Ahmed, Ayesha Ejaz; Masood, Komal; Dean, Sohni Vicky; Shakir, Tanzila; Kardar, Ahmed Abdul Hafeez; Barlass, Usman; Imam, Syed Haider; Mohmand, Mohammad Ghawar Khan; Ibrahim, Hussain; Khan, Imad Saeed; Akram, Usman; Hasnain, Farid
2011-04-01
To assess the levels of stress in the face of terrorism and the adopted coping strategies, amongst the student population of universities in Karachi. A descriptive, cross sectional study was conducted on undergraduate students from four universities of Karachi. Self-administered questionnaires were filled out by 291 students. Pearson Chi-Square test was used to assess associations between stress levels and different variables at a level of significance of 0.05%. A total of 65.8% of the students had mild stress levels, 91.5% of university students were exposed to terrorism through television, while only 26.5% students reported personal exposure to terrorism. 67.4% students were forbidden by their parents to go out (p = 0.002). Most of those who had self exposure to an attack were the ones whose parents forbade them from going out (p = 0.00). Most commonly used coping strategy was increased faith in religion. Irritability was the most common stress symptom. A majority of students studying in universities of Karachi had mild stress levels due to the constant threat of terrorism whereas a minority had severe stress levels. Possible reasons for resilience and only mild stress levels could be the history of Karachi's internal conflicts and its prolonged duration of being exposed to terrorism. These students who are positive for stress need to be targeted for counseling either through the media or through their universities. More extensive research is needed in this area.
Zheng, Xiliang; Wang, Jin
2015-01-01
We uncovered the universal statistical laws for the biomolecular recognition/binding process. We quantified the statistical energy landscapes for binding, from which we can characterize the distributions of the binding free energy (affinity), the equilibrium constants, the kinetics and the specificity by exploring the different ligands binding with a particular receptor. The results of the analytical studies are confirmed by the microscopic flexible docking simulations. The distribution of binding affinity is Gaussian around the mean and becomes exponential near the tail. The equilibrium constants of the binding follow a log-normal distribution around the mean and a power law distribution in the tail. The intrinsic specificity for biomolecular recognition measures the degree of discrimination of native versus non-native binding and the optimization of which becomes the maximization of the ratio of the free energy gap between the native state and the average of non-native states versus the roughness measured by the variance of the free energy landscape around its mean. The intrinsic specificity obeys a Gaussian distribution near the mean and an exponential distribution near the tail. Furthermore, the kinetics of binding follows a log-normal distribution near the mean and a power law distribution at the tail. Our study provides new insights into the statistical nature of thermodynamics, kinetics and function from different ligands binding with a specific receptor or equivalently specific ligand binding with different receptors. The elucidation of distributions of the kinetics and free energy has guiding roles in studying biomolecular recognition and function through small-molecule evolution and chemical genetics. PMID:25885453
Universal size dependence of auger constants in direct- and indirect-gap semiconductor nanocrystals
Energy Technology Data Exchange (ETDEWEB)
Robel, Istvan [Los Alamos National Laboratory; Schaller, Richard D [Los Alamos National Laboratory; Klimov, Victor I [Los Alamos National Laboratory; Gresback, Ryan [U OF MINNESOTA; Kortshagen, Uwe [U OF MINNESOTA
2008-01-01
Three-dimensional (3D) spatial confinement of electronic wave functions in semiconductor nanocrystals (NCs) results in a significant enhancement of multi-electron phenomena including non radiative Auger recombination. In this process, a conduction-band electron recombines with a valence-band hole by transferring the recombination energy to a third carrier. Significant interest in Auger recombination in NCs has been stimulated by recent studies ofNC lasing, and generation-III photovoltaics enabled by carrier multiplication because in both of these prospective applications Auger recombination represents a dominant carrier-loss mechanism. Here, we perform a side-by-side comparison of Auger recombination rates in NCs of several different compositions including Ge, PbSe, InAs, and CdSe. We observe that the only factor, which has a significant effect on the measured recombination rates, is the size of the NCs but not the details of the material's electronic structure. Most surprisingly, comparable rates are measured for nanocrystals of directand indirect-gap semiconductor NCs despite a dramatic four-to-five orders of magnitude difference in respective bulk-semiconductor Auger constants. This unusual observation can be explained by confinement-induced relaxation of momentum conservation, which smears out the difference between direct- and indirect-gap materials.
DEFF Research Database (Denmark)
Liang, Xiaodong; Kontogeorgis, Georgios
2015-01-01
resolved the mostly criticized numerical pitfall, that is, the presence of more than three volume roots at real application conditions. Finally, the possibility of using the original PC-SAFT EOS parameters with the new universal constants has been investigated for the phase equilibria of the systems......The Perturbed Chain-Statistical Associating Fluid Theory Equation of State (PC-SAFT EOS) has been successfully applied to model phase behavior of various types of systems, while it is also well-known that the PC-SAFT EOS has difficulties in describing some second-order derivative properties...... roots, have been analyzed. Then, a practical procedure has been proposed to refit the universal constants of the PC-SAFT EOS with the purpose of fixing the numerical pitfalls in the real application ranges and reusing the original parameters. It is shown that the new universal constants have practically...
Event soil loss, runoff and the Universal Soil Loss Equation family of models: A review
Kinnell, P. I. A.
2010-05-01
SummaryThe Universal Soil Loss Equation (USLE) is the most widely used and misused prediction equation in the world. Although it was designed to predict long-term average annual soil loss, it has the capacity to predict event soil losses reasonably well at some geographic locations and not well at others. Its lack of capacity to predict event erosion is highly influenced by the fact the event rainfall-runoff factor used in the USLE and its revisions (RUSLE, RUSLE2) does not consider runoff explicitly. While including direct consideration of runoff in the event rainfall-runoff factor improves the capacity to predict event erosion when runoff is measured, that capacity is reduced by inaccurate runoff prediction methods. Even so, the predictions may be better than when the traditional event rainfall-runoff factor is used if the rainfall-runoff model used to predict runoff works reasonably well. Direct consideration of runoff in the rainfall-runoff factor may improve the ability of the model to account for seasonal effects. It also enhances the ability of the model to account for the spatial variations in soil loss on hillslopes which result from spatial variations in soil and vegetation. However, the USLE model will not provide a capacity to account for deposition taking place on concave hillslopes unless it is coupled with an appropriate sediment transport model, as in done in RUSLE2. Changing the basis of the event rainfall-runoff factor has consequences on a number of the other factors used in the model, in particular new values of the soil erodibility factor need to be determined. Using runoff values from cropped areas is necessary to account for differences in infiltration capacities between vegetated and tilled bare fallow areas, but requires re-evaluation of the crop factors.
Energy Technology Data Exchange (ETDEWEB)
Burgazli, Alvina [Odessa National University, Department of Theoretical Physics, Odessa (Ukraine); Eingorn, Maxim [Odessa National University, Astronomical Observatory, Odessa (Ukraine); Odessa National Polytechnic University, Department of Theoretical and Experimental Nuclear Physics, Odessa (Ukraine); North Carolina Central University, CREST and NASA Research Centers, Durham, NC (United States); Zhuk, Alexander [Odessa National University, Astronomical Observatory, Odessa (Ukraine)
2015-03-01
In this paper, we consider the Universe at the late stage of its evolution and deep inside the cell of uniformity. At these scales, the Universe is filled with inhomogeneously distributed discrete structures (galaxies, groups and clusters of galaxies). Supposing that the Universe contains also the cosmological constant and a perfect fluid with a negative constant equation of state (EoS) parameter ω (e.g., quintessence, phantom or frustrated network of topological defects), we investigate scalar perturbations of the Friedmann-Robertson-Walker metrics due to inhomogeneities. Our analysis shows that, to be compatible with the theory of scalar perturbations, this perfect fluid, first, should be clustered and, second, should have the EoS parameter ω = -1/3. In particular, this value corresponds to the frustrated network of cosmic strings. Therefore, the frustrated network of domain walls with ω = -2/3 is ruled out. A perfect fluid with ω = -1/3 neither accelerates nor decelerates the Universe. We also obtain the equation for the nonrelativistic gravitational potential created by a system of inhomogeneities. Due to the perfect fluid with ω = -1/3, the physically reasonable solutions take place for flat, open and closed Universes. This perfect fluid is concentrated around the inhomogeneities and results in screening of the gravitational potential. (orig.)
Burgazli, Alvina; Eingorn, Maxim; Zhuk, Alexander
In this paper, we consider the Universe at the late stage of its evolution and deep inside the cell of uniformity. At these scales, the Universe is filled with inhomogeneously distributed discrete structures (galaxies, groups and clusters of galaxies). Supposing that the Universe contains also the cosmological constant and a perfect fluid with a negative constant equation of state (EoS) parameter [Formula: see text] (e.g., quintessence, phantom or frustrated network of topological defects), we investigate scalar perturbations of the Friedmann-Robertson-Walker metrics due to inhomogeneities. Our analysis shows that, to be compatible with the theory of scalar perturbations, this perfect fluid, first, should be clustered and, second, should have the EoS parameter [Formula: see text]. In particular, this value corresponds to the frustrated network of cosmic strings. Therefore, the frustrated network of domain walls with [Formula: see text] is ruled out. A perfect fluid with [Formula: see text] neither accelerates nor decelerates the Universe. We also obtain the equation for the nonrelativistic gravitational potential created by a system of inhomogeneities. Due to the perfect fluid with [Formula: see text], the physically reasonable solutions take place for flat, open and closed Universes. This perfect fluid is concentrated around the inhomogeneities and results in screening of the gravitational potential.
Roatta, Luca
2017-01-01
Assuming that space and time can only have discrete values, we obtain the expression of the gravitational potential energy that at large distance coincides with the Newtonian. In very precise circumstances it coincides with the relativistic mass-energy relation: this shows that the Universe is a black hole in which all bodies are subjected to an acceleration toward the border of the Universe itself. Since the Universe is a black hole with a fixed radius, we can obtain the density of the Unive...
Creating the Universe Without a Singularity and the Cosmological Constant Problem
Guendelman, E. I.
2013-01-01
We consider a non singular origin for the Universe starting from an Einstein static Universe in the framework of a theory which uses two volume elements $\\sqrt{-{g}}d^{4}x$ and $\\Phi d^{4}x$, where $\\Phi $ is a metric independent density, also curvature, curvature square terms, first order formalism and for scale invariance a dilaton field $\\phi$ are considered in the action. In the Einstein frame we also add a cosmological term that parametrizes the zero point fluctuations. The resulting eff...
Livio, Mario
2000-12-01
Advance Praise for The Accelerating Universe "The Accelerating Universe is not only an informative book about modern cosmology. It is rich storytelling and, above all, a celebration of the human mind in its quest for beauty in all things." -Alan Lightman, author of Einstein's Dreams "This is a wonderfully lucid account of the extraordinary discoveries that have made the last years a golden period for observational cosmology. But Mario Livio has not only given the reader one clear explanation after another of what astronomers are up to, he has used them to construct a provocative argument for the importance of aesthetics in the development of science and for the inseparability of science, art, and culture." -Lee Smolin, author of The Life of the Cosmos "What a pleasure to read! An exciting, simple account of the universe revealed by modern astronomy. Beautifully written, clearly presented, informed by scientific and philosophical insights." -John Bahcall, Institute for Advanced Study "A book with charm, beauty, elegance, and importance. As authoritative a journey as can be taken through modern cosmology." -Allan Sandage, Observatories of the Carnegie Institution of Washington
La jurisdicción universal: una realidad en constante construcción
Directory of Open Access Journals (Sweden)
Luis Peraza
2006-01-01
Full Text Available Muchas críticas se han suscitado y se suscitarán con respecto a la sentencia del constitucional español. España es la patria del genial y universal Quijote de Cervantes y, como tal, acepta todos los crímenes internacionales que se le presenten. Luchará contra gigantes pero la clave es pensar que son sólo molinos de viento que dejarán de agitar sus armas cuando el viento de la impunidad amaine y su círculo vicioso se rompa. El principio dejurisdicción universal es un imperativo humanitario, una exigencia ética, una obligación política y una necesidad jurídica impostergable. El ciclo de la lluvia es la mejor imagen para reflejar la relación entre el derecho y la justicia, tanto nacional como internacional. El derecho y la justicia nacional son como un mar de sentencias y leyes, la mejor parte del cual se va evaporando y condensando en un cielo preñado paulatinamente de nubes que serían el derecho y la justicia internacional. Una vez cristalizado, se desata una lluvia sobre el mar en forma de derecho y justicia internacional que influye, se mezcla y se diluye, en su descarga, en el mar nacional. La influencia es mutua, recíproca y simbiótica ya que enriquece todas las esferas del derecho y la justicia. Para conseguir la aplicación efectiva del ideal de justicia internacional, los tribunales internacionales y nacionales deben seguir creando derecho y jurisprudencia que se base en un único, desbordante e irradiante concepto: la dignidad del ser humano. Como dice Peter Häberle "a nosotros nos queda en la actualidad, ni más ni menos, la tarea de crear un derecho constitucional nacional, regional y universal de la dignidad humana".
Dynamically avoiding fine-tuning the cosmological constant: the ''Relaxed Universe''
Energy Technology Data Exchange (ETDEWEB)
Bauer, Florian; Solà, Joan [High Energy Physics Group, Dept. ECM, and Institut de Ciències del Cosmos Univ. de Barcelona, Av. Diagonal 647, E-08028 Barcelona, Catalonia (Spain); Štefancić, Hrvoje, E-mail: fbauer@ecm.ub.es, E-mail: sola@ecm.ub.es, E-mail: shrvoje@thphys.irb.hr [Theoretical Physics Division, Rudjer Bošković Institute, PO Box 180, HR-10002 Zagreb (Croatia)
2010-12-01
We demonstrate that there exists a large class of F(R,G) action functionals of the scalar curvature and of the Gauß-Bonnet invariant which are able to relax dynamically a large cosmological constant (CC), whatever it be its starting value in the early universe. Hence, it is possible to understand, without fine-tuning, the very small current value Λ{sub 0} ∼ H{sub 0}{sup 2} of the CC as compared to its theoretically expected large value in quantum field theory and string theory. In our framework, this relaxation appears as a pure gravitational effect, where no ad hoc scalar fields are needed. The action involves a positive power of a characteristic mass parameter, M, whose value can be, interestingly enough, of the order of a typical particle physics mass of the Standard Model of the strong and electroweak interactions or extensions thereof, including the neutrino mass. The model universe emerging from this scenario (the ''Relaxed Universe'') falls within the class of the so-called ΛXCDM models of the cosmic evolution. Therefore, there is a ''cosmon'' entity X (represented by an effective object, not a field), which in this case is generated by the effective functional F(R,G) and is responsible for the dynamical adjustment of the cosmological constant. This model universe successfully mimics the essential past epochs of the standard (or ''concordance'') cosmological model (ΛCDM). Furthermore, it provides interesting clues to the coincidence problem and it may even connect naturally with primordial inflation.
Loss of Accreditation at Historically Black Colleges and Universities
Baylor, Rhonda E.
2010-01-01
For nearly two centuries, historically Black colleges and universities (HBCUs) have provided educational opportunities to millions of students who were disenfranchised from traditional higher education institutions. HBCUs have provided African Americans and international students of color with a sense of self-worth and accomplishment. However,…
National Research Council Canada - National Science Library
Hodzic, A; Aumont, B; Knote, C; Lee‐Taylor, J; Madronich, S; Tyndall, G
2014-01-01
...) is largely unconstrained in current chemistry‐climate models. We apply the Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere to calculate Henry's law constants for these intermediate species...
Hamada, T.; Yamamoto, T.; Momida, H.; Uda, T.; Ohno, T.; Tajima, N.; Hasaka, S.; Inoue, M.; Kobaysahi, N.
2006-06-01
We have developed a first principles software, universal virtual spectroscope for opto-electronics research (UVSOR), which can calculate dielectric functions of materials at atomistic levels on the basis of the density functional pseudopotential method in the frequency range from the static to ultra-violet region. The UVSOR can calculate separately electronic and lattice components of the dielectric function, by using the random phase approximation and the Berry phase polarization theory, respectively. This makes the UVSOR unique "virtual spectroscope" on computer, covering all frequencies interested in materials science; i. e., radio, Tera-Hz, infrared, visible, and ultra-violet frequencies. Since the UVSOR can quantitatively calculate the dielectric constant of materials, it is quite effective for studying new dielectrics such as high-k and low-k materials discussed in nano-scale semiconductor technologies. The UVSOR is free software and can be downloaded from our web site: .
De Martini, Francesco
2017-10-01
The nature of the scalar field responsible for the cosmological inflation is found to be rooted in the most fundamental concept of Weyl's differential geometry: the parallel displacement of vectors in curved space-time. Within this novel geometrical scenario, the standard electroweak theory of leptons based on the SU(2)L⊗U(1)Y as well as on the conformal groups of space-time Weyl's transformations is analysed within the framework of a general-relativistic, conformally covariant scalar-tensor theory that includes the electromagnetic and the Yang-Mills fields. A Higgs mechanism within a spontaneous symmetry breaking process is identified and this offers formal connections between some relevant properties of the elementary particles and the dark energy content of the Universe. An `effective cosmological potential': Veff is expressed in terms of the dark energy potential: via the `mass reduction parameter': , a general property of the Universe. The mass of the Higgs boson, which is considered a `free parameter' by the standard electroweak theory, by our theory is found to be proportional to the mass which accounts for the measured cosmological constant, i.e. the measured content of vacuum-energy in the Universe. The non-integrable application of Weyl's geometry leads to a Proca equation accounting for the dynamics of a φρ-particle, a vector-meson proposed as an an optimum candidate for dark matter. On the basis of previous cosmic microwave background results our theory leads, in the condition of cosmological `critical density', to the assessment of the average energy content of the φρ-excitation. The peculiar mathematical structure of Veff offers a clue towards a very general resolution of a most intriguing puzzle of modern quantum field theory, the `Cosmological Constant Paradox' (here referred to as the `Λ-Paradox'). Indeed, our `universal' theory offers a resolution of the Λ-Paradox for all exponential inflationary potentials: VΛ(T,φ)∝e-nφ, and for all
De Martini, Francesco
2017-11-13
The nature of the scalar field responsible for the cosmological inflation is found to be rooted in the most fundamental concept of Weyl's differential geometry: the parallel displacement of vectors in curved space-time. Within this novel geometrical scenario, the standard electroweak theory of leptons based on the SU(2) L ⊗U(1) Y as well as on the conformal groups of space-time Weyl's transformations is analysed within the framework of a general-relativistic, conformally covariant scalar-tensor theory that includes the electromagnetic and the Yang-Mills fields. A Higgs mechanism within a spontaneous symmetry breaking process is identified and this offers formal connections between some relevant properties of the elementary particles and the dark energy content of the Universe. An 'effective cosmological potential': Veff is expressed in terms of the dark energy potential: [Formula: see text] via the 'mass reduction parameter': [Formula: see text], a general property of the Universe. The mass of the Higgs boson, which is considered a 'free parameter' by the standard electroweak theory, by our theory is found to be proportional to the mass [Formula: see text] which accounts for the measured cosmological constant, i.e. the measured content of vacuum-energy in the Universe. The non-integrable application of Weyl's geometry leads to a Proca equation accounting for the dynamics of a ϕρ -particle, a vector-meson proposed as an an optimum candidate for dark matter. On the basis of previous cosmic microwave background results our theory leads, in the condition of cosmological 'critical density', to the assessment of the average energy content of the ϕρ -excitation. The peculiar mathematical structure of Veff offers a clue towards a very general resolution of a most intriguing puzzle of modern quantum field theory, the 'Cosmological Constant Paradox' (here referred to as the 'Λ-Paradox'). Indeed, our 'universal' theory offers a resolution of the Λ-Paradox for all
Ludescher, J.; Tsallis, C.; Bunde, A.
2011-09-01
We consider 16 representative financial records (stocks, indices, commodities, and exchange rates) and study the distribution PQ(r) of the interoccurrence times r between daily losses below negative thresholds -Q, for fixed mean interoccurrence time RQ. We find that in all cases, PQ(r) follows the form PQ(r)~1/[(1+(q- 1)βr]1/(q-1), where β and q are universal constants that depend only on RQ, but not on a specific asset. While β depends only slightly on RQ, the q-value increases logarithmically with RQ, q=1+q0 ln(RQ/2), such that for RQ→2, PQ(r) approaches a simple exponential, PQ(r)cong2-r. The fact that PQ does not scale with RQ is due to the multifractality of the financial markets. The analytic form of PQ allows also to estimate both the risk function and the Value-at-Risk, and thus to improve the estimation of the financial risk.
Hodzic, A.; Aumont, B.; Knote, C.; Lee-Taylor, J.; Madronich, S.; Tyndall, G.
2014-07-01
The water solubility of oxidation intermediates of volatile organic compounds that can condense to form secondary organic aerosol (SOA) is largely unconstrained in current chemistry-climate models. We apply the Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere to calculate Henry's law constants for these intermediate species. Results show a strong negative correlation between Henry's law constants and saturation vapor pressures. Details depend on precursor species, extent of photochemical processing, and NOx levels. Henry's law constants as a function of volatility are made available over a wide range of vapor pressures for use in 3-D models. In an application using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) over the U.S. in summer, we find that dry (and wet) deposition of condensable organic vapors leads to major reductions in SOA, decreasing surface concentrations by ~50% (10%) for biogenic and ~40% (6%) for short chain anthropogenic precursors under the considered volatility conditions.
Huizinga, Richard J.
2014-01-01
Streamflow data, basin characteristics, and rainfall data from 39 streamflow-gaging stations for urban areas in and adjacent to Missouri were used by the U.S. Geological Survey in cooperation with the Metropolitan Sewer District of St. Louis to develop an initial abstraction and constant loss model (a time-distributed basin-loss model) and a gamma unit hydrograph (GUH) for urban areas in Missouri. Study-specific methods to determine peak streamflow and flood volume for a given rainfall event also were developed.
Energy Technology Data Exchange (ETDEWEB)
Diaz-Guillen, M. r.; Fuentes, A. F.; Diaz-Guillen, J. a.; Santamaria, J.; Leon, C.
2012-07-01
We report on ac conductivity measurement of oxide ion conductors with composition Gd{sub 2}(ZryTi{sub 1}-y){sub 2}O{sub 7} and a pyrochlore type structure, at temperatures between -20 and 250 degree centigrade and in the frequency range from 1 Hz to 3 MHz by using impedance spectroscopy. Results show that a crossover from a power law dependence to a linear frequency dependence (or nearly constant loss behavior) in the ac conductivity can be clearly observed in a wide temperature range. This crossover is found to be thermally activated, and its activation energy ENCL to be much lower than the activation energy Edc for the dc conductivity. We also found that the values of ENCL are almost independent of composition, and therefore of the concentration of mobile oxygen vacancies, unlike those of Edc. Moreover, for each composition, the values of E{sub N}CL=0.67{+-}0.04 eV are very similar to those estimated for the energy barrier for the ions to leave their cages, E{sub {alpha}}=0.69{+-}0.05 eV. These results support that the nearly constant loss behavior, ubiquitous in ionic conductors, is originated from caged ion dynamics. (Author) 33 refs.
Universal effective coupling constant ratios of 3D scalar ϕ4 field theory and pseudo-ϵ expansion
Directory of Open Access Journals (Sweden)
Sokolov A. I.
2016-01-01
Full Text Available The ratios R2k = g2k/gk − 14 of renormalized coupling constants g2k entering the small-field equation of state approach universal values R*2k at criticality. They are calculated for the three-dimensional λϕ4 field theory within the pseudo-ϵ expansion approach. Pseudo-ϵ expansions for R*6, R*8, R*10 are derived in the five-loop approximation, numerical estimates are obtained with a help of the Padé–Borel–Leroy resummation technique. Its use gives R*6 = 1.6488, the number which perfectly agrees with the most recent lattice result R*6 = 1.649. For the octic coupling the pseudo-ϵ expansion is less favorable numerically. Nevertheless the Padé–Borel–Leroy resummation leads to the estimate R*8 = 0.890 close to the values R*8 = 0.87, R*8 = 0.857 extracted from the lattice and field-theoretical calculations. The pseudo-ϵ expansion for R*10 turns out to have big and rapidly increasing coefficients. This makes correspondent estimates strongly dependent on the Borel–Leroy shift parameter b and prevents proper evaluation of R*10
Ninomiya, K.; Akiyama, T.; Hata, M.; Hatori, M.; Iguri, T.; Ikeda, Y.; Inaba, S.; Kawamura, H.; Kishi, R.; Murakami, H.; Nakaya, Y.; Nishio, H.; Ogawa, N.; Onishi, J.; Saiba, S.; Sakuta, T.; Tanaka, S.; Tanuma, R.; Totsuka, Y.; Tsutsui, R.; Watanabe, K.; Murata, J.
2017-09-01
The composition dependence of gravitational constant G is measured at the millimeter scale to test the weak equivalence principle, which may be violated at short range through new Yukawa interactions such as the dilaton exchange force. A torsion balance on a turning table with two identical tungsten targets surrounded by two different attractor materials (copper and aluminum) is used to measure gravitational torque by means of digital measurements of a position sensor. Values of the ratios \\tilde{G}_Al-W/\\tilde{G}_Cu-W -1 and \\tilde{G}_Cu-W/GN -1 were (0.9 +/- 1.1sta +/- 4.8sys) × 10-2 and (0.2 +/- 0.9sta +/- 2.1sys) × 10-2 , respectively; these were obtained at a center to center separation of 1.7 cm and surface to surface separation of 4.5 mm between target and attractor, which is consistent with the universality of G. A weak equivalence principle (WEP) violation parameter of η_Al-Cu(r∼ 1 cm)=(0.9 +/- 1.1sta +/- 4.9sys) × 10-2 at the shortest range of around 1 cm was also obtained.
Zhang, Xianhong; Ma, Yuhong; Zhao, Changwen; Yang, Wantai
2014-06-01
Interfacial interaction and compatibility between the ceramic dielectric and polymer matrix have strong impact on the dielectric permittivity and dielectric loss of their composites. In this work, we presented a simple strategy to fabricate flexible dielectric composite of high dielectric constant BaTiO3 (BT) nanofiber and ferroelectric poly(vinylidene fluoride) (PVDF) matrix. The electrospun BT nanofiber was sintered at about 800 °C to form perovskite crystalline. Fluorosilane 1H,1H,2H,2H-perfluorooctyltrimethoxysilane was used to introduce a short perfluoroalkyl chain to the surface of BT nanofiber by silane coupling. The effects of content of modified BT nanofiber on the dielectric performance of the composites were investigated by broadband dielectric spectroscopy. The results in comparison with pure PVDF showed that the dielectric constant increased about 2 times (from 10 to 22) and dielectric loss tan δ reduced about 50% (from 0.12 to 0.06) when the loading of modified BT nanofiber was up to 20 v%. In the same loading fraction of BT nanofibers (10 v%), the dielectric loss of fluorosilane modified sample (tan δ = 0.08) was lower than that of unmodified one (tan δ = 0.1). In the range of 20-100 °C, the k showed almost no dependence on the temperature. However, the dielectric loss revealed a trend of decreasing at first and increased later with the increasing of temperature, and reached the lowest value (tanδ = 0.01) at about 60 °C.
A non-parametric/parametric analysis of the universal soil loss equation
Sonneveld, B.G.J.S.; Nearing, M.A.
2003-01-01
Due to its modest data demands and transparent model structure, the Universal Soil Loss Equation (USLE) remains the most popular tool for water erosion hazard assessment. However, the model has several shortcomings, two of which are likely to have prominent implications for the model results. First,
A non-parametric/parametric analysis of the universal soil loss equation
Sonneveld, B.G.J.S.; Nearing, M.A.
2002-01-01
Due to its modest data demands and transparent model structure, the Universal Soil Loss Equation (USLE) remains the most popular tool for water erosion hazard assessment. However, the model has several shortcomings, two of which are likely to have prominent implications for the model results. First,
Hydrologic Impacts of Oak Harvesting and Evaluation of the Modified Universal Soil Loss Equation
Charlette R. Epifanio; Michael J. Singer; Xiaohong Huang
1991-01-01
Two Sierra foothill watersheds were monitored to learn what effects selective oak removal would have on watershed hydrology and water quality. We also used the data to generate sediment rating curves and evaluate the modified universal soil loss equation (MUSLE). Annual sediment rating curves better accounted for the variability in precipitation events from year to...
Guendelman, Eduardo; Labrana, Pedro
2013-01-01
We consider a non-singular origin for the Universe starting from an Einstein static Universe, the so called "emergent universe" scenario, in the framework of a theory which uses two volume elements $\\sqrt{-{g}}d^{4}x$ and $\\Phi d^{4}x$, where $\\Phi $ is a metric independent density, used as an additional measure of integration. Also curvature, curvature square terms and for scale invariance a dilaton field $\\phi$ are considered in the action. The first order formalism is applied. The integrat...
Directory of Open Access Journals (Sweden)
Wen-hai Zhang
2009-06-01
Full Text Available Six types of runoff plots were set up and an experimental study was carried out to examine natural rate of soil and water loss in the granite gneiss region of northern Jiangsu Province in China. Through correlation analysis of runoff and soil loss during 364 rainfall events, a simplified and convenient mathematical formula suitable for calculating the rainfall erosivity factor (R for the local region was established. Other factors of the universal soil loss equation (USLE model were also determined. Relative error analysis of the soil loss of various plots calculated by the USLE model on the basis of the observed values showed that the relative error ranged from -3.5% to 9.9% and the confidence level was more than 90%. In addition, the relative error was 5.64% for the terraced field and 12.36% for the sloping field in the practical application. Thus, the confidence level was above 87.64%. These results provide a scientific basis for forecasting and monitoring soil and water loss, for comprehensive management of small watersheds, and for soil and water conservation planning in the region.
Kaminska, Ewa; Tarnacka, Magdalena; Madejczyk, Olga; Chrobok, Anna; Kaminski, Kamil; Paluch, Marian
2016-04-07
The molecular dynamics of three saccharides: D-glucose, 1,6-anhydro-D-glucose (levoglucosan) and 1,6:2,3-dianhydro-β-D-mannopyranose of various degrees of freedom, number of hydroxyl groups and internal structures was investigated over a wide range of temperatures and frequencies by means of Broadband Dielectric Spectroscopy (BDS). Despite the pronounced variety in the physicochemical properties of the carbohydrates, no change in the shape of the structural relaxation process was observed in the vicinity of the glass transition temperature (β(KWW) = 0.5). On the other hand further studies of the Debye-Stokes-Einstein relationship between dc conductivity and structural dynamics revealed some significant changes connected with the ability to form strong H-bonded structures. Moreover the presence of nearly constant loss (NCL) at moderate frequencies and just below the T(g) in the glassy state of levoglucosan and 1,6:2,3-dianhydro-β-D-mannopyranose was noticeable. We followed the temperature evolution of ε'' located at frequencies f = 0.1 kHz and f = 1 kHz, where the NCL is detected. Interestingly, a clear change in the dynamics far below the glass transition was observed in both compounds. This crossover (T(c)), found in different materials, and studied by various experimental techniques, is usually interpreted as being caused by the freezing of the Johari-Goldstein (JG) relaxation process. Alternatively it can also be due to the increasing anharmonicity in the density of vibrational states. Interestingly, it was shown that the slope of ε''(T) measured above the T(c) slightly changes while below the T(c) stays constant after physical aging. This is related to the densification of the sample that might result in steric hindrance and suppression of some kind of motion occurring in the glassy state, involving the larger parts of the molecules.
Universal Coherence-Induced Power Losses of Quantum Heat Engines in Linear Response.
Brandner, Kay; Bauer, Michael; Seifert, Udo
2017-10-27
We identify a universal indicator for the impact of coherence on periodically driven quantum devices by dividing their power output into a classical contribution and one stemming solely from superpositions. Specializing to Lindblad dynamics and small driving amplitudes, we derive general upper bounds on both the coherent and the total power of cyclic heat engines. These constraints imply that, for sufficiently slow driving, coherence inevitably leads to power losses in the linear-response regime. We illustrate our theory by working out the experimentally relevant example of a single-qubit engine.
Nesbitt, F. L.; Monks, P. S.; Payne, W. A.; Stief, L. J.; Toumi, R.
1995-01-01
The absolute rate constant for the reaction O((3)P) + HOBr has been measured between T = 233K and 423K using the discharge-flow kinetic technique coupled to mass spectrometric detection. The value of the rate coefficient at room temperature is (2.5 +/- 0.6) x 10(exp -11)cu cm/molecule/s and the derived Arrhenius expression is (1.4 +/- 0.5) x 10(exp -10) exp((-430 +/- 260)/T)cu cm/molecule/s. From these rate data the atmospheric lifetime of HOBr with respect to reaction with O((3)P) is about 0.6h at z = 25 km which is comparable to the photolysis lifetime based on recent measurements of the UV cross section for HOBr. Implications for HOBr loss in the stratosphere have been tested using a 1D photochemical box model. With the inclusion of the rate parameters and products for the O + HOBr reaction, calculated concentration profiles of BrO increase by up to 33% around z = 35 km. This result indicates that the inclusion of the O + HOBr reaction in global atmospheric chemistry models may have an impact on bromine partitioning in the middle atmosphere.
Wu, Qi; Sun, Baozhu; Wang, Shuqin; Zhao, Lianying; Qi, Feng
2013-01-01
The present paper proposes a new approach for fitting the plasma effect-site equilibrium rate constant (Ke0) of propofol to satisfy the condition that the effect-site concentration (Ce) is equal at the time of loss of consciousness (LOC) and recovery of consciousness (ROC). Forty patients receiving intravenous anesthesia were divided into 4 groups and injected propofol 1.4, 1.6, 1.8, or 2 mg/kg at 1,200 mL/h. Durations from the start of injection to LOC and to ROC were recorded. LOC and ROC were defined as an observer's assessment of alertness and sedation scale change from 3 to 2 and from 2 to 3, respectively. Software utilizing bisection method iteration algorithms was built. Then, Ke0 satisfying the CeLOC=CeROC condition was estimated. The accuracy of the Ke0 estimated by our method was compared with the Diprifusor TCI Pump built-in Ke0 (0.26 min(-1)), and the Orchestra Workstation built-in Ke0 (1.21 min(-1)) in another group of 21 patients who were injected propofol 1.4 to 2 mg/kg. Our results show that the population Ke0 of propofol was 0.53 ± 0.18 min(-1). The regression equation for adjustment by dose (mg/kg) and age was Ke0=1.42-0.30 × dose-0.0074 × age. Only Ke0 adjusted by dose and age achieved the level of accuracy required for clinical applications. We conclude that the Ke0 estimated based on clinical signs and the two-point fitting method significantly improved the ability of CeLOC to predict CeROC. However, only the Ke0 adjusted by dose and age and not a fixed Ke0 value can meet clinical requirements of accuracy.
Sound Pressure Levels Measured in a University Concert Band: A Risk of Noise-Induced Hearing Loss?
Holland, Nicholas V., III
2008-01-01
Researchers have reported public school band directors as experiencing noise-induced hearing loss. Little research has focused on collegiate band directors and university student musicians. The present study measures the sound pressure levels generated within a university concert band and compares sound levels with the criteria set by the…
Webb, Marquitta C.; Salandy, Sinead T.; Beckford, Safiya E.
2016-01-01
Objective: To investigate the hydration status pre- and post-training among university athletes using urine color and weight loss as indicators. Participants: Participants were 52 university athletes training for campus games in a developing country. Methods: Pre- and post-training urine specimens were compared with a standard urine color scale.…
Social work with a pet loss support group in a university veterinary hospital.
Dunn, Kathleen L; Mehler, Stephen J; Greenberg, Helaine S
2005-01-01
This article describes the development of a bereavement support group for pet owners in a university veterinary hospital. The group is predicated on the understanding that a human-animal relationship can be strong and the loss of that bond, through the animal's death, can produce a grief reaction, though this problem is often overlooked. The description of the support group is presented in detail so that it may be replicated. Included are: the history of the group, the procedure for making clients aware of the group, the program, the demographics, and problems brought to the group. The discussion and conclusion support the development of interdisciplinary collaborations among veterinarians, owners and social workers in other veterinary hospitals.
Universal relation between spectroscopic constants
Indian Academy of Sciences (India)
potential curve by revoking the idea of valence state [11] and thereby the valence state dissociation energy, DVS which refers to an asymptote in which atoms are in suitable va- lence state. He has introduced a new dimensionless parameter z analogous to Sutherland parameter and equal to ker2 e/DVS. He found that F and ...
Universal relation between spectroscopic constants
Indian Academy of Sciences (India)
diatomic molecules, G Herzberg, vol. I, 2nd ed., p. 459, paragraph 2). His wrong definition has resulted in highly erroneous values of re. (2) With our equation lnG = 1.91578 + 0.9711lnA (omitting the standard de- viations) the value of re for Li2 X. 1Σ+ g comes out to be 2.52 oA against the experimental value of 2.6729 oA.
LOSS-OF-COOLANT ACIDENT SIMULATIONS IN THE NATIONAL RESEARCH UNIVERSAL REACTOR
Energy Technology Data Exchange (ETDEWEB)
Bennett, W D; Goodman, R L; Heaberlin, S W; Hesson, G M; Nealley, C; Kirg, L L; Marshall, R K; McNair, G W; Meitzler, W D; Neally, G W; Parchen, L J; Pilger, J P; Rausch, W N; Russcher, G E; Schreiber, R E; Wildung, N J
1981-02-01
Pressurized water reactor loss-of-coolant accident (LOCA) phenomena are being simulated with a series of experiments in the U-2 loop of the National Research Universal Reactor at Chalk River, Ontario, Canada. The first of these experiments includes up to 45 parametric thermal-hydraulic tests to establish the relationship among the reflood delay time of emergency coolant, the reflooding rate, and the resultant fuel rod cladding peak temperature. Subsequent experiments establish the fuel rod failure characteristics at selected peak cladding temperatures. Fuel rod cladding pressurization simulates high burnup fission gas pressure levels of modern PWRs. This document contains both an experiment overview of the LOCA simulation program and a review of the safety analyses performed by Pacific Northwest Laboratory (PNL) to define the expected operating conditions as well as to evaluate the worst case operating conditions. The primary intent of this document is to supply safety information required by the Chalk River Nuclear Laboratories (CRNL), to establish readiness to proceed from one test phase to the next and to establish the overall safety of the experiment. A hazards review summarizes safety issues, normal operation and three worst case accidents that have been addressed during the development of the experiment plan.
Park, Soyoung; Jin, Cheunggil; Choi, Chuluong
2011-11-01
Loss of soil has become a problem worldwide, and as concerns about the environment grow, active research has begun regarding soil erosion and soil-preservation polices. This study analyzed the trend of soil loss in South Korea over the past 30-year and predicted future soil loss in 2020 using the revised universal soil loss equation. In the period 1975-2005, soil loss showed an increasing trend, the 2005 value represents a 0.59 Mg/ha (2.58%) increase. Scenario 1 assumes that urban areas have a similar trend to that between 1975 and 2005 and that precipitation amount follows scenario A1B of the IPCC. The soil loss amount for 2020 land-cover map that account for the ECVAM should increase by 25.0~26.3% compared to 1975. In the case where the ECVAM is not considered, soil loss should increase by 27.7~31.8%. In Scenario 2, in which the urban area and precipitation follow the same trend as between 1975 and 2005, soil loss for 2020 land-cover map that consider the ECVAM will increase by 6.8%~7.9% compared to 1975. When the ECVAM is not considered, soil loss will increase by 9.1~12.6%. The environmental and legislative value of preservation should be considered to minimize erosion and allow for more sustainable development.
Energy Technology Data Exchange (ETDEWEB)
Robinson, H.P.; Potter, Elinor
1971-03-01
This collection of mathematical data consists of two tables of decimal constants arranged according to size rather than function, a third table of integers from 1 to 1000, giving some of their properties, and a fourth table listing some infinite series arranged according to increasing size of the coefficients of the terms. The decimal values of Tables I and II are given to 20 D.
Spatial Data Mining for Estimating Cover Management Factor of Universal Soil Loss Equation
Tsai, F.; Lin, T. C.; Chiang, S. H.; Chen, W. W.
2016-12-01
Universal Soil Loss Equation (USLE) is a widely used mathematical model that describes long-term soil erosion processes. Among the six different soil erosion risk factors of USLE, the cover-management factor (C-factor) is related to land-cover/land-use. The value of C-factor ranges from 0.001 to 1, so it alone might cause a thousandfold difference in a soil erosion analysis using USLE. The traditional methods for the estimation of USLE C-factor include in situ experiments, soil physical parameter models, USLE look-up tables with land use maps, and regression models between vegetation indices and C-factors. However, these methods are either difficult or too expensive to implement in large areas. In addition, the values of C-factor obtained using these methods can not be updated frequently, either. To address this issue, this research developed a spatial data mining approach to estimate the values of C-factor with assorted spatial datasets for a multi-temporal (2004 to 2008) annual soil loss analysis of a reservoir watershed in northern Taiwan. The idea is to establish the relationship between the USLE C-factor and spatial data consisting of vegetation indices and texture features extracted from satellite images, soil and geology attributes, digital elevation model, road and river distribution etc. A decision tree classifier was used to rank influential conditional attributes in the preliminary data mining. Then, factor simplification and separation were considered to optimize the model and the random forest classifier was used to analyze 9 simplified factor groups. Experimental results indicate that the overall accuracy of the data mining model is about 79% with a kappa value of 0.76. The estimated soil erosion amounts in 2004-2008 according to the data mining results are about 50.39 - 74.57 ton/ha-year after applying the sediment delivery ratio and correction coefficient. Comparing with estimations calculated with C-factors from look-up tables, the soil erosion
Directory of Open Access Journals (Sweden)
Valdecir Antoninho Dalpasquale
2012-03-01
Full Text Available Drying of agricultural products at high temperatures can be simulated by mathematical models, which intend to describe the drying process close to commercial patterns. They are based on simultaneous heat and mass transfer between the product that is losing moisture, and the air that is supplying energy to the process. All models use these balances, never allowing values of relative humidity of the air to be greater than 100%. However, it has not been common to evaluate air enthalpy, which should not have significant variation during the entire process, accepted as adiabatic. In this work, a mathematical model is proposed for fixed-bed corn (Zea mays L. drying simulation, according to the Michigan State University (MSU model. In the numerical solution, the enthalpy of the drying air was maintained constant as a quantitative physical indicator for correction of the heat and mass exchange in each step of the process, in order to obtain more real evaluations in all drying stages, and in the results for final moisture of the grain. As a result, greater space and time intervals for the simulation were possible. The simulation was validated by comparisons with literature results.
Gallant, Annette R; Pérusse-Lachance, Émilie; Provencher, Véronique; Bégin, Catherine; Drapeau, Vicky
2013-12-01
To characterise individuals who reported present and past weight loss behaviours on psycho-behavioural factors known to influence body weight, e.g. overeating, dietary restriction. An online questionnaire was distributed to a university community. Questions pertaining to present weight loss, previous weight loss, eating behaviour tendencies, perceived stress and sleep quality were answered by 3,069 individuals. Body weight and height were self-reported. Present and past weight loss behaviours were prevalent in the sample, with 33.3 % of the participants who reported trying to lose weight, 33.1 % who reported having previously lost weight (>10 lbs), and 18.8 % who reported repeated weight loss behaviour (i.e. present and past weight loss behaviours). Trying to lose weight and previous weight loss were both independently associated with increased risk for psycho-behavioural characteristics known to be associated with obesity, e.g. overeating tendencies, perceived stress, short sleep duration. This risk was particularly elevated among the underweight/normal-weight individuals who reported repeated weight loss behaviours. Indeed, adjusted odds ratios for reporting restrictive and overeating tendencies, perceived stress and short sleep for these individuals were significantly higher compared to their underweight/normal-weight peers who did not report repeated weight loss behaviours (adjusted odds ratios 4.7, 2.7, 1.8, and 1.8, respectively, p weight individuals reporting weight loss behaviours are characterised by a psycho-behaviour profile which may further increase their risk of weight gain.
Directory of Open Access Journals (Sweden)
Jaime Schumacher
2015-06-01
Full Text Available A study of 56 professors at five American universities found that a majority had little understanding of principles, well-known in the field of data curation, informing the ongoing administration of digital materials and chose to manage and store work-related data by relying on the use of their own storage devices and cloud accounts. It also found that a majority of them had experienced the loss of at least one work-related digital object that they considered to be important in the course of their professional career. Despite such a rate of loss, a majority of respondents expressed at least a moderate level of confidence that they would be able to make use of their digital objects in 25 years. The data suggest that many faculty members are unaware that their data is at risk. They also indicate a strong correlation between faculty members’ digital object loss and their data management practices. University professors producing digital objects can help themselves by becoming aware that these materials are subject to loss. They can also benefit from awareness and use of better personal data management practices, as well as participation in university-level programmatic digital curation efforts and the availability of more readily accessible, robust infrastructure for the storage of digital materials.
Energy Technology Data Exchange (ETDEWEB)
Dalouji, V. [Razi University, Kermanshah (Iran, Islamic Republic of); Elahi, S. M. [Razi University, Kermanshah (Iran, Islamic Republic of); Islamic Azad University, Tehran (Iran, Islamic Republic of)
2014-03-15
In this work, the optical properties of carbon - nickel films annealed at different temperatures (300 - 1000 deg C) were investigated. The films were grown on quartz substrates by radio frequency magnetron co-sputtering at room temperature with a deposition time of 600 second. The optical transmittance spectra in the wavelength range 300 - 1000 nm were used to compute the refractive index by using the Swanepoel's method. The films annealed at 500 deg C showed considerable optical loss due to optical absorption by nickel atoms and to scattering caused by surface roughness. However, the film annealed at 800 deg C had a very small optical loss in spite of the high surface roughness. The dispersion curves of the refractive indices of the films had anomalous dispersion in the absorption region and normal dispersion in the transparent region. The dissipation rate of the electromagnetic wave at 500 deg C was shown to have maximum value.
Leading and Learning in Schools and Universities: Losses and Gains 1968-2008
Barker, Bernard
2009-01-01
This paper explores important points of similarity and difference between schools and universities on three dimensions: (1) the working life and goals of participants in schools and universities; (2) the leadership and organisation of the institutions; and (3) the curriculum, teaching and learning that takes place. The aim is to discover by…
Yang, Ke; Huang, Xingyi; Xie, Liyuan; Wu, Chao; Jiang, Pingkai; Tanaka, Toshikatsu
2012-11-23
A novel route to prepare core-shell structured nanocomposites with excellent dielectric performance is reported. This approach involves the grafting of polystyrene (PS) from the surface of BaTiO(3) by an in situ RAFT polymerization. The core-shell structured PS/BaTiO(3) nanocomposites not only show significantly increased dielectric constant and very low dielectric loss, but also have a weak frequency dependence of dielectric properties over a wide range of frequencies. In addition, the dielectric constant of the nanocomposites can also be easily tuned by varying the thickness of the PS shell. Our method is very promising for preparing high-performance nanocomposites used in energy-storage devices. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Bouguerra Hamza
2017-03-01
Full Text Available Soil erosion by water is a major problem that the Northern part of Algeria witnesses nowadays; it reduces: the productivity of agricultural areas due to the loss of lands, and leads to the loss of storage capacity in reservoirs, the deterioration of water quality etc. The aim of this study is to evaluate the soil losses due to water erosion, and to identify the sectors which are potentially sensitive to water erosion in the Bouhamdane watershed, that is located in the northeastern part of Algeria. To this end, the Revised Universal Soil Loss Equation (RUSLE was used. The application of this equation takes into account five parameters, namely the rainfall erosivity, topography, soil erodibility, vegetative cover and erosion control practices. The product of these parameters under GIS using the RUSLE mathematical equation has enabled evaluating an annual average erosion rate for the Bouhamdane watershed of 11.18 t·ha-1·y-1. Based on the estimates of soil loss in each grid cell, a soil erosion risk map with five risk classes was elaborated. The spatial distribution of risk classes was 16% very low, 41% low, 28% moderate, 12% high and 3% very high. Most areas showing high and very high erosion risk occurred in the lower Bouhamdane watershed around Hammam Debagh dam. These areas require adequate erosion control practices to be implemented on a priority basis in order to conserve soil resources and reduce siltation in the reservoir.
Jackson, Neal
2015-01-01
I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. There are two broad categories of measurements. The first uses individual astrophysical objects which have some property that allows their intrinsic luminosity or size to be determined, or allows the determination of their distance by geometric means. The second category comprises the use of all-sky cosmic microwave background, or correlations between large samples of galaxies, to determine information about the geometry of the Universe and hence the Hubble constant, typically in a combination with other cosmological parameters. Many, but not all, object-based measurements give H0 values of around 72-74 km s(-1) Mpc(-1), with typical errors of 2-3 km s(-1) Mpc(-1). This is in mild discrepancy with CMB-based measurements, in particular those from the Planck satellite, which give values of 67-68 km s(-1) Mpc(-1) and typical errors of 1-2 km s(-1) Mpc(-1). The size of the remaining systematics indicate that accuracy rather than precision is the remaining problem in a good determination of the Hubble constant. Whether a discrepancy exists, and whether new physics is needed to resolve it, depends on details of the systematics of the object-based methods, and also on the assumptions about other cosmological parameters and which datasets are combined in the case of the all-sky methods.
Roessler, Kurt
The scientific and human relations of Albert Einstein and Georges Lemaître are discussed. In 1927 the later had interpreted the general theory of relativity for a model of an expanding cosmos using a positive value of the cosmological constant. In the three open questions between them: expansion of cosmos, primordial state of a quantum vacuum (``primeval atom''), importance of the cosmological constant for vacuum energy, Lemaître finally won over the heavily opposing Einstein. The philosophical and ontological tendency of Einstein's thinking was contrasted with the strict epistemological line of the catholic priest Lemaître. The dramatic changes between friendship and controversy finally led to a diminution of Lemaître's reputation as ``Darwin of Cosmology''. In that case, the late Einstein proved to be a hindrance rather than a promoter of evolution in cosmology.
Marjanne Senekal; Gabrielle L. Lasker; Lindsay van Velden; Ria Laubscher; Norman J. Temple
2016-01-01
Abstract Background Female university students are at risk for weight gain and use of inappropriate weight-loss strategies. By gaining a greater understanding of the weight-loss strategies used by and weight management related characteristics of these students, effective weight management interventions for this vulnerable group can be developed. Methods Two hundred and fifty female students from South Africa universities, aged 18–25 years, participated in this cross-sectional study; 162 attem...
Dielectric Constant and Loss Data. Part 4
1980-12-01
0669 .1703 .1858 .1984 .190 .0528 .0163 .005 MAG-20 50 wt% 20 mesh magnetite I K’ 25.7 25.4 24.2 23.6 23.1 13.1 17.2 23.9 tan 6 .111 .109 .116 .114...101 .0475 .03 .03 Ij /po 1.75 1.57 1.44 1.37 1.12 .937 .897 1.03 tan 6 m .276 .325 .378 .423 .515 .579 .49 .30 MAG-65 50 wt% 65 mesh magnetite K... Refractories , cements, 8-3 "E," IV-ll Greenstone, Virginia, P.R.-139 General Electric 101, clear, P.R.-85-87 GR-I (butyl rubber) and compound, IV-52 iron
Dielectric Constant and Loss Data, Part 3
1977-05-01
Glass, aluminum borosilicate, IV-10 Green Refractories , cements, 8-3 aluminum zinc-phosphate, IV-9 Greenstone, Virginia, P.R.-139 barium borosilicate...34Lucite" HlC 202, V-10 IIV-43 "Lucite" 104-119 and HH-140, IV-34,70 Magnetite and plastic mixtures, IV-44,45 itLucite," sintered, IV-34 Mallinckrodt
Directory of Open Access Journals (Sweden)
Neal Jackson
2015-09-01
Full Text Available I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. There are two broad categories of measurements. The first uses individual astrophysical objects which have some property that allows their intrinsic luminosity or size to be determined, or allows the determination of their distance by geometric means. The second category comprises the use of all-sky cosmic microwave background, or correlations between large samples of galaxies, to determine information about the geometry of the Universe and hence the Hubble constant, typically in a combination with other cosmological parameters. Many, but not all, object-based measurements give H_0 values of around 72–74 km s^–1 Mpc^–1, with typical errors of 2–3 km s^–1 Mpc^–1. This is in mild discrepancy with CMB-based measurements, in particular those from the Planck satellite, which give values of 67–68 km s^–1 Mpc^–1 and typical errors of 1–2 km s^–1 Mpc^–1. The size of the remaining systematics indicate that accuracy rather than precision is the remaining problem in a good determination of the Hubble constant. Whether a discrepancy exists, and whether new physics is needed to resolve it, depends on details of the systematics of the object-based methods, and also on the assumptions about other cosmological parameters and which datasets are combined in the case of the all-sky methods.
The Henry's constant of monochloramine.
Garcia, Miguel A; Anderson, Michael A
2018-02-01
Monochloramine is a secondary disinfectant used in drinking water and is also formed in chlorinated wastewater. While known to hydrolyze over time and react with dissolved organic matter, its partitioning between the aqueous and gas phase has not been extensively studied. Preliminary experiments demonstrated that monochloramine concentrations in solutions open to the atmosphere or actively aerated decreased more rapidly than in sealed solutions, indicating significant losses to the atmosphere. For example, a monochloramine solution open to the atmosphere yielded a loss rate constant of 0.08 d-1, a value twice that for sealed samples without headspace (0.04 d-1) where loss occurs exclusively as a result of hydrolysis. A solution aerated at 10 mL s-1 had a loss rate constant nearly 10× greater than that for hydrolysis alone (0.35 d-1). To better understand partitioning of monochloramine to the gas phase and potential for volatilization, the dimensionless Henry's law constants of monochloramine (KH) were determined using an equilibrium headspace technique at five different temperatures (11, 16, 21, 27, and 32 °C). The resulting values ranged from 8 × 10-3 to 4 × 10-2, indicating a semi-volatile compound, and were found to be consistent with quantitative structure activity relationship predictions. At 20 °C, monochloramine exhibits a dimensionless Henry's constant of about 1.7 × 10-2 which is 35 times greater than ammonia but comparable to the Henry's constant of inorganic semi-volatile compounds such sulfur dioxide. The Henry's constant values for monochloramine suggests that volatilization could be a relevant loss process in open systems such as rivers receiving chlorinated wastewater effluent, swimming pools and cooling towers. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Ali Zamani
2010-04-01
Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: American pediatric Association proposes to screen all neonates with Oto-Acoustic Emission (OAE. In developing countries, because of several limitations, health policy makers recommend to screen only in high risk patients. This study is performed with the aim to screen hearing loss in 950 high risk newborns hospitalized in hospitals affiliated to Tehran University using the OAE test."n"nMethods: A total of 950 neonates hospitalized in the Neonatal and NICU wards of Vali-e-Asr, Shariati, Medical Center and Bahrami Hospitals during the years 2004-2006 who showed at least one risk factor using TEOAE hearing test were enrolled into this cross-sectional descriptive analytical study and were diagnosed with mild deafness and total deafness. Blood exchange due to hyperbillirubinemia, septicemia, congenital heart disease, the fifth minute apgar scores below six, PROM more than six hours, epilepsia, need to NICU more than five hours, pneumonia and Oto-Toxic drugs were considered as risk factors. Data was past medical history, current disease, admission cause, sign & symptoms and complications of disease."n"nResults: Multivariate logistic regression and paired t-test showed that blood exchange, low birth weight and low
Wormholes and the cosmological constant
Klebanov, Igor; Susskind, Leonard; Banks, Tom
1989-05-01
We review Coleman's wormhole mechanism for the vanishing of the cosmological constant. We show that in a minisuperspace model wormhole-connected universes dominate the path integral. We also provide evidence that the euclidean path integral over geometries with spherical topology is unstable with respect to formation of infinitely many wormhole-connected 4-spheres. Consistency is restored by summing over all topologies, which leads to Coleman's result. Coleman's argument for determination of other parameters is reviewed and applied to the mass of the pion. A discouraging result is found that the pion mass is driven to zero. We also consider qualitatively the implications of the wormhole theory for cosmology. We argue that a small number of universes containing matter and energy may exist in contact with infinitely many cold and empty universe. Contact with the cold universe insures that the cosmological constant in the warm ones in zero.
Wormholes and the cosmological constant
Energy Technology Data Exchange (ETDEWEB)
Klebanov, I.; Susskind, L.; Banks, T.
1989-05-08
We review Coleman's wormhole mechanism for the vanishing of the cosmological constant. We show that in a minisuperspace model wormhole-connected universes dominate the path integral. We also provide evidence that the euclidean path integral over geometries with spherical topology is unstable with respect to formation of infinitely many wormhole-connected 4-spheres. Consistency is restored by summing over all topologies, which leads to Coleman's result. Coleman's argument for determination of other parameters is reviewed and applied to the mass of the pion. A discouraging result is found that the pion mass is driven to zero. We also consider qualitatively the implications of the wormhole theory for cosmology. We argue that a small number of universes containing matter and energy may exist in contact with infinitely many cold and empty universes. Contact with the cold universes insures that the cosmological constant in the warm ones is zero.
Lemaître, Georges
2013-08-01
This is an English translation of a paper by Georges Lemaître, first published in French in 1927, in which the author, having re-discovered and generalised the Friedmann models, for the first time related them to the then-already-available observations of expansion of the Universe. The translation published in 1931 in MNRAS was not perfectly faithful to the original text—it was updated. As it turned out very recently, the updates were done by Lemaître himself, but the discrepancies between the two texts caused a temporary stir among historians. Our translation follows the 1927 version exactly. The paper has been selected by the Editors of General Relativity and Gravitation for republication in the Golden Oldies series of the journal. This republication is accompanied by an editorial note written by Jean-Pierre Luminet that, among other things, lists and explains the differences between the 1927 and 1931 versions.
Directory of Open Access Journals (Sweden)
Jackson Neal
2007-09-01
Full Text Available I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. In the last 20 years, much progress has been made and estimates now range between 60 and 75 km s^-1 Mpc^-1, with most now between 70 and 75 km s^-1 Mpc^-1, a huge improvement over the factor-of-2 uncertainty which used to prevail. Further improvements which gave a generally agreed margin of error of a few percent rather than the current 10% would be vital input to much other interesting cosmology. There are several programmes which are likely to lead us to this point in the next 10 years.
Varying Constants, Gravitation and Cosmology.
Uzan, Jean-Philippe
2011-01-01
Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.
Varying Constants, Gravitation and Cosmology
Directory of Open Access Journals (Sweden)
Jean-Philippe Uzan
2011-03-01
Full Text Available Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.
Directory of Open Access Journals (Sweden)
Elena Grigoryeva
2015-05-01
Full Text Available Universities occupy a special place in the city’s life, the place where centuries-old traditions of the past meet the future. Universities keep their ancestral roots stretching back into the Middle Ages. University rooms and laboratories are the places where the future of science and society is built and discussed.The oldest Siberian University located in Tomsk was included in the City Charter as a city-forming enterprise. Other Siberian cities have not yet come to such deep comprehension of the role of universities. But who can doubt the significance and beneficence of this role?A complex and debatable process of reformation of the Russian higher education has been going on for several decades. Many things are perceived painfully. Irkutsk has been a student city for a long time and ranked second in the percentage of students among citizens. But recently we have lost Irkutsk High Military Aviation Engineering School, nearly lost the MIA High School. Pedagogical University has lost its status of university, and then its independence. Linguistic University has turned into a branch of Moscow University…Besides, external threats still exist and even grow. The lands and the buildings of universities are of keen interest among big businessmen, speculators and developers… Isn’t it the reason why the ideas to evacuate universities to suburban campuses arise increasingly frequently?What is the impact of dislocation of universities out of the city historical center? Does it make the city poorer and older? Or safer and more manageable? As usual, we tried to show the challenge and diversity of the main topic of the issue.
Valkama, Elena; Lemola, Riitta; Känkänen, Hannu; Turtola, Eila
2016-04-01
and red clovers) did not diminish the risk for N leaching. Otherwise, the effect on N leaching and its risk were consistent across the studies conducted in different countries on clay and coarse-textured mineral soils with different ploughing times, N fertilization rates (50-160 kg/ ha), and amounts of annual precipitation (480-1040 mm). Non-legume catch crops reduced grain yield by 3% with no changes in grain N content. In contrast, legumes and mixed catch crops increased both grain yield and grain N content by 6%. In spring cereal production, undersown non-legume catch crops are deemed a universal and effective method for reducing N leaching loss across the various soils, management practices and weather conditions in the Nordic countries. The environmental benefits of using non-legume catch crops appear considerable compared to the adverse reduction in grain yields, amounting to only a few percent. Catch crops are advisable for fields at high risk for N leaching (e.g., sandy soils or soils and crops requiring high N fertilization).
Effective cosmological constant induced by stochastic fluctuations of Newton's constant
Directory of Open Access Journals (Sweden)
Marco de Cesare
2016-09-01
Full Text Available We consider implications of the microscopic dynamics of spacetime for the evolution of cosmological models. We argue that quantum geometry effects may lead to stochastic fluctuations of the gravitational constant, which is thus considered as a macroscopic effective dynamical quantity. Consistency with Riemannian geometry entails the presence of a time-dependent dark energy term in the modified field equations, which can be expressed in terms of the dynamical gravitational constant. We suggest that the late-time accelerated expansion of the Universe may be ascribed to quantum fluctuations in the geometry of spacetime rather than the vacuum energy from the matter sector.
Energy Technology Data Exchange (ETDEWEB)
Gaffar, M.A. [Physics Department, School of Science and Engineering, American University in Cairo, Cairo 11511 (Egypt); Abousehly, A.M.; Mostafa, M.M. [Physics Department, Faculty of Science, Al-Azhar University, 71524 Assiut (Egypt); Abu El-Fadl, A. [Physics Department, Faculty of Science, Assiut University, 71516 Assiut (Egypt)
2006-11-15
The dielectric constant ({epsilon}), dielectric loss (tan{delta}) and ac conductivity ({sigma}{sub ac}) of virgin and thermally cycled undoped and Ni{sup 2+}-doped K{sub 2}ZnCl{sub 4}(KZC) crystals in the ferroelectric-commensurate (FC), incommensurate (IC) and normal phases (N) have been studied. Anomalous behaviour at the two-phase transition points was observed while measuring {epsilon} along the polar a-axis for the undoped sample. With increasing Ni {sup 2+}concentration a systematic shift of the phase transition temperature towards lower values and a continuous inhibition of the peak height were detected. {epsilon} changed linearly with lnf up to f=10{sup 5} Hz. tan {delta} along the a-axis declared the phase transitions by peak changes. After Ni {sup 2+}-doping this behaviour was preserved at the FC-IC phase transition point while the IC-N phase transition was manifested by a change in the slope of the straight line representing the tan {delta}-T dependence. The ac conductivity changed lineally with frequency according to a relation of the form {sigma}{sub ac}={sigma}{sub o} f{sup {beta}} where 0>{beta}>1.9{sigma}{sub ac} increased monotonically with increasing temperature and doping concentration in the low-temperature phases tending to merge in one straight-line with high activation energy that might be due to superionic dc conduction in the high temperature N-phase. Doping with Ni{sup 2+} pinned stripples, decreased the soliton-soliton interaction, weakened discommensuration effects, shortened the IC-phase and strongly affected the 'chaotic' behaviour at the T{sub C-IC}. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
Zhang, Hongming; Wei, Jicheng; Yang, Qinke; Baartman, Jantiene E.M.; Gai, Lingtong; Yang, Xiaomei; Li, Shu Qin; Yu, Jiantao; Ritsema, Coen J.; Geissen, Violette
2017-01-01
The Universal Soil Loss Equation (USLE) and its revised version (RUSLE) are often used to estimate soil erosion at regional landscape scales. USLE/RUSLE contain parameters for slope length factor (L) and slope steepness factor (S), usually combined as LS. However a major limitation is the difficulty
Cunningham, Debra Jayne
2015-01-01
Using a constructivist grounded theory approach (Charmaz, 2006), this qualitative study examined how eight female senior-level professionals employed at faith-based colleges and universities processed and navigated the experience of involuntary job loss and successfully transitioned to another position. The theoretical framework of psychological…
Cosmological constant, fine structure constant and beyond
Energy Technology Data Exchange (ETDEWEB)
Wei, Hao; Zou, Xiao-Bo; Li, Hong-Yu; Xue, Dong-Ze [Beijing Institute of Technology, School of Physics, Beijing (China)
2017-01-15
In the present work, we consider the cosmological constant model Λ ∝ α{sup -6}, which is well motivated from three independent approaches. As is well known, the hint of varying fine structure constant α was found in 1998. If Λ ∝ α{sup -6} is right, it means that the cosmological constant Λ should also be varying. Here, we try to develop a suitable framework to model this varying cosmological constant Λ ∝ α{sup -6}, in which we view it from an interacting vacuum energy perspective. Then we consider the observational constraints on these models by using the 293 Δα/α data from the absorption systems in the spectra of distant quasars. We find that the model parameters can be tightly constrained to the very narrow ranges of O(10{sup -5}) typically. On the other hand, we can also view the varying cosmological constant model Λ ∝ α{sup -6} from another perspective, namely it can be equivalent to a model containing ''dark energy'' and ''warm dark matter'', but there is no interaction between them. We find that this is also fully consistent with the observational constraints on warm dark matter. (orig.)
Ion exchange equilibrium constants
Marcus, Y
2013-01-01
Ion Exchange Equilibrium Constants focuses on the test-compilation of equilibrium constants for ion exchange reactions. The book first underscores the scope of the compilation, equilibrium constants, symbols used, and arrangement of the table. The manuscript then presents the table of equilibrium constants, including polystyrene sulfonate cation exchanger, polyacrylate cation exchanger, polymethacrylate cation exchanger, polysterene phosphate cation exchanger, and zirconium phosphate cation exchanger. The text highlights zirconium oxide anion exchanger, zeolite type 13Y cation exchanger, and
A new cosmological constant model
López, J L; Lopez, J; Nanopoulos, D
1996-01-01
We propose a new cosmological model with a time-dependent cosmological constant (\\Lambda\\propto 1/t^2), which starting at the Planck time as \\Lambda_{Pl}\\sim M^2_{Pl}, evolves to the present-day allowed value of \\Lambda_0\\sim10^{-120}M^2_{Pl}. This scenario is supported by non-critical string theory considerations. We compute the age of the Universe and the time-dependence of the scale factor in this model, and find general agreement with recent determinations of the Hubble parameter for substantial values of \\Omega_{\\rm \\Lambda}. This effectively low-density open Universe model differs from the traditional cosmological constant model, and has observable implications for particle physics and cosmology.
Cosmological Constant, Fine Structure Constant and Beyond
Wei, Hao; Li, Hong-Yu; Xue, Dong-Ze
2016-01-01
In this work, we consider the cosmological constant model $\\Lambda\\propto\\alpha^{-6}$, which is well motivated from three independent approaches. As is well known, the evidence of varying fine structure constant $\\alpha$ was found in 1998. If $\\Lambda\\propto\\alpha^{-6}$ is right, it means that the cosmological constant $\\Lambda$ should be also varying. In this work, we try to develop a suitable framework to model this varying cosmological constant $\\Lambda\\propto\\alpha^{-6}$, in which we view it from an interacting vacuum energy perspective. We propose two types of models to describe the evolutions of $\\Lambda$ and $\\alpha$. Then, we consider the observational constraints on these models, by using the 293 $\\Delta\\alpha/\\alpha$ data from the absorption systems in the spectra of distant quasars, and the data of type Ia supernovae (SNIa), cosmic microwave background (CMB), baryon acoustic oscillation (BAO). We find that the model parameters can be tightly constrained to the narrow ranges of ${\\cal O}(10^{-5})$ t...
1995-08-01
about the distances to galaxies and thereby about the expansion rate of the Universe. A simple way to determine the distance to a remote galaxy is by measuring its redshift, calculate its velocity from the redshift and divide this by the Hubble constant, H0. For instance, the measured redshift of the parent galaxy of SN 1995K (0.478) yields a velocity of 116,000 km/sec, somewhat more than one-third of the speed of light (300,000 km/sec). From the universal expansion rate, described by the Hubble constant (H0 = 20 km/sec per million lightyears as found by some studies), this velocity would indicate a distance to the supernova and its parent galaxy of about 5,800 million lightyears. The explosion of the supernova would thus have taken place 5,800 million years ago, i.e. about 1,000 million years before the solar system was formed. However, such a simple calculation works only for relatively ``nearby'' objects, perhaps out to some hundred million lightyears. When we look much further into space, we also look far back in time and it is not excluded that the universal expansion rate, i.e. the Hubble constant, may have been different at earlier epochs. This means that unless we know the change of the Hubble constant with time, we cannot determine reliable distances of distant galaxies from their measured redshifts and velocities. At the same time, knowledge about such change or lack of the same will provide unique information about the time elapsed since the Universe began to expand (the ``Big Bang''), that is, the age of the Universe and also its ultimate fate. The Deceleration Parameter q0 Cosmologists are therefore eager to determine not only the current expansion rate (i.e., the Hubble constant, H0) but also its possible change with time (known as the deceleration parameter, q0). Although a highly accurate value of H0 has still not become available, increasing attention is now given to the observational determination of the second parameter, cf. also the Appendix at the
Deformed extra space and the smallness of the cosmological constant
Rubin, Sergey G
2016-01-01
The mechanism of different universes formation is elaborated. Each universe is characterized by a unique cosmological constant. It is shown that the set of cosmological constants has the cardinality of the continuum and contains zero cosmological constant. Those universes with cosmological constants near zero could be filled by complex structures. There is no necessity in a special mechanism of the fine tuning. The role of quantum fluctuations is studied.
Senekal, Marjanne; Lasker, Gabrielle L; van Velden, Lindsay; Laubscher, Ria; Temple, Norman J
2016-09-01
Female university students are at risk for weight gain and use of inappropriate weight-loss strategies. By gaining a greater understanding of the weight-loss strategies used by and weight management related characteristics of these students, effective weight management interventions for this vulnerable group can be developed. Two hundred and fifty female students from South Africa universities, aged 18-25 years, participated in this cross-sectional study; 162 attempted weight loss during the year preceding the study (dieters) and 88 were non-dieters. Weight and height were measured and BMI (kg/m(2)) computed. A self-administered questionnaire was used to record all other variables. Weight loss strategies were described for dieters and compared between BMI groups within the dieters group. Weight management related characteristics were compared between dieters and non-dieters. Statistical tests included Pearson Chi-square test, independent samples t-test or Mann-Whitney U test (depending on distribution of the data). Predictors for a higher BMI and being overweight/obese (BMI ≥25 kg/m(2)) were identified using regression models. Healthy weight-loss strategies included increased exercise and fruit/vegetable intake and decreased intake of sugar and fat containing items; unhealthy methods included eating little food and skipping meals; and extreme weight loss strategies included laxatives and vomiting. The most commonly used weight-loss product was Herbex. Dieters were characterized by a higher BMI, overestimation of their weight (especially normal weight students), dissatisfaction with weight and select body parts, higher intake of breakfast and healthy foods, lower intake of unhealthy foods, higher levels of vigorous physical activity, higher use of select informal weight-loss information sources and experiencing more pressure to lose weight from mothers, siblings and friends. Predictors of higher BMI and/or increased risk for BMI ≥25 included weight-loss attempt
Directory of Open Access Journals (Sweden)
Marjanne Senekal
2016-09-01
Full Text Available Abstract Background Female university students are at risk for weight gain and use of inappropriate weight-loss strategies. By gaining a greater understanding of the weight-loss strategies used by and weight management related characteristics of these students, effective weight management interventions for this vulnerable group can be developed. Methods Two hundred and fifty female students from South Africa universities, aged 18–25 years, participated in this cross-sectional study; 162 attempted weight loss during the year preceding the study (dieters and 88 were non-dieters. Weight and height were measured and BMI (kg/m2 computed. A self-administered questionnaire was used to record all other variables. Weight loss strategies were described for dieters and compared between BMI groups within the dieters group. Weight management related characteristics were compared between dieters and non-dieters. Statistical tests included Pearson Chi-square test, independent samples t-test or Mann-Whitney U test (depending on distribution of the data. Predictors for a higher BMI and being overweight/obese (BMI ≥25 kg/m2 were identified using regression models. Results Healthy weight-loss strategies included increased exercise and fruit/vegetable intake and decreased intake of sugar and fat containing items; unhealthy methods included eating little food and skipping meals; and extreme weight loss strategies included laxatives and vomiting. The most commonly used weight-loss product was Herbex. Dieters were characterized by a higher BMI, overestimation of their weight (especially normal weight students, dissatisfaction with weight and select body parts, higher intake of breakfast and healthy foods, lower intake of unhealthy foods, higher levels of vigorous physical activity, higher use of select informal weight-loss information sources and experiencing more pressure to lose weight from mothers, siblings and friends. Predictors of higher BMI and/or increased
Valido Quintana, Mercedes; Oviedo Santos, Ángeles; Borkoski Barreiro, Silvia; Santana Rodríguez, Alfredo; Ramos Macías, Ángel
Sixty percent of prelingual hearing loss is of genetic origin. A family history of permanent childhood hearing loss is a risk factor. The objective of the study is to determine the relationship between this risk factor and hearing loss. We have evaluated clinical and epidemiological characteristics and related nonsyndromic genetic variation. This was a retrospective, descriptive and observational study of newborns between January 2007 and December 2010 with family history as risk factor for hearing loss using transient evoked otoacoustic emissions and auditory brainstem response. A total of 26,717 children were born. Eight hundred and fifty-seven (3.2%) had family history. Fifty-seven(0.21%) failed to pass the second test. A percentage of 29.1 (n=16) had another risk factor, and 17.8% (n=9) had no classical risk factor. No risk factor was related to the hearing loss except heart disease. Seventy-six point four percent had normal hearing and 23.6% hearing loss. The mean of family members with hearing loss was 1.25. On genetic testing, 82.86% of homozygotes was normal, 11.43% heterozygosity in Connexin 26 gene (35delG), 2.86% R143W heterozygosity in the same gene and 2.86% mutant homozygotes (35delG). We found no relationship between hearing loss and mutated allele. The percentage of children with a family history and hearing loss is higher than expected in the general population. The genetic profile requires updating to clarify the relationship between hearing loss and heart disease, family history and the low prevalence in the mutations analyzed. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. All rights reserved.
The case for the cosmological constant
Indian Academy of Sciences (India)
I present a short overview of current observational results and theoretical models for a cosmological constant. The main motivation for invoking a small cosmological constant (or -term) at the present epoch has to do with observations of high redshift Type Ia supernovae which suggest an accelerating universe.
The case for the cosmological constant
Indian Academy of Sciences (India)
Abstract. I present a short overview of current observational results and theoretical models for a cosmological constant. The main motivation for invoking a small cosmological constant (orA-term) at the present epoch has to do with observations of high redshift Type Ia supernovae which suggest an accelerating universe.
2009-01-01
The Universe, is one book in the Britannica Illustrated Science Library Series that is correlated to the science curriculum in grades 5-8. The Britannica Illustrated Science Library is a visually compelling set that covers earth science, life science, and physical science in 16 volumes. Created for ages 10 and up, each volume provides an overview on a subject and thoroughly explains it through detailed and powerful graphics-more than 1,000 per volume-that turn complex subjects into information that students can grasp. Each volume contains a glossary with full definitions for vocabulary help and an index.
2011-01-01
Updated for 2011, the Universe, is one book in the Britannica Illustrated Science Library Series that covers today's most popular science topics, from digital TV to microchips to touchscreens and beyond. Perennial subjects in earth science, life science, and physical science are all explored in detail. Amazing graphics-more than 1,000 per title-combined with concise summaries help students understand complex subjects. Correlated to the science curriculum in grades 5-9, each title also contains a glossary with full definitions for vocabulary.
On Aryabhata's Planetary Constants
Kak, Subhash
2001-01-01
This paper examines the theory of a Babylonian origin of Aryabhata's planetary constants. It shows that Aryabhata's basic constant is closer to the Indian counterpart than to the Babylonian one. Sketching connections between Aryabhata's framework and earlier Indic astronomical ideas on yugas and cyclic calendar systems, it is argued that Aryabhata's system is an outgrowth of an earlier Indic tradition.
Generalized Pickands constants
K.G. Debicki
2001-01-01
textabstractPickands constants play an important role in the exact asymptotic of extreme values for Gaussian stochastic processes. By the {it generalized Pickands constant ${cal H_{eta$ we mean the limit begin{eqnarray* {cal H_{eta= lim_{T to inftyfrac{ {cal H_{eta(T){T, end{eqnarray* where ${cal
Deconstructing the Cosmological Constant
Jejjala, V; Minic, D; Jejjala, Vishnu; Leigh, Robert G.; Minic, Djordje
2003-01-01
Deconstruction provides a novel way of dealing with the notoriously difficult ultraviolet problems of four-dimensional gravity. This approach also naturally leads to a new perspective on the holographic principle, tying it to the fundamental requirements of unitarity and diffeomorphism invariance, as well as to a new viewpoint on the cosmological constant problem. The numerical smallness of the cosmological constant is implied by a unique combination of holography and supersymmetry, opening a new window into the fundamental physics of the vacuum.
Directory of Open Access Journals (Sweden)
Pelin Ozgur Polat
2015-10-01
The primary aim of this project is to gather information through using different methods and investigate the determinants of message persuasiveness in university students from the British and Turkish cultures in order to design effective physical activity messages leading intention, attitude and behaviour change. The results of the finalized studies showed the importance of using both qualitative and quantitative methods in message design process.
Betanzos Arroyo, L. I.; Prol Ledesma, R. M.; da Silva Pinto da Rocha, F. J. P.
2014-12-01
The Universal Soil Loss Equation (USLE), which is considered to be a contemporary approach in soil loss assessment, was used to assess soil erosion hazard in the Zacatecas mining district. The purpose of this study is to produce erosion susceptibility maps for an area that is polluted with mining tailings which are susceptible to erosion and can disperse the particles that contain heavy metals and other toxic elements. USLE method is based in the estimation of soil loss per unit area and takes into account specific parameters such as precipitation data, topography, soil erodibility, erosivity and runoff. The R-factor (rainfall erosivity) was calculated from monthly and annual precipitation data. The K-factor (soil erodibility) was estimated using soil maps available from the CONABIO at a scale of 1:250000. The LS-factor (slope length and steepness) was determined from a 30-m digital elevation model. A raster-based Geographic Information System (GIS) was used to interactively calculate soil loss and map erosion hazard. The results show that estimated erosion rates ranged from 0 to 4770.48 t/ha year. Maximum proportion of the total area of the Zacatecas mining district have nil to very extremely slight erosion severity. Small areas in the central and south part of the study area shows the critical condition requiring sustainable land management.
Peselnick, L.; Robie, R.A.
1962-01-01
The recent measurements of the elastic constants of calcite by Reddy and Subrahmanyam (1960) disagree with the values obtained independently by Voigt (1910) and Bhimasenachar (1945). The present authors, using an ultrasonic pulse technique at 3 Mc and 25??C, determined the elastic constants of calcite using the exact equations governing the wave velocities in the single crystal. The results are C11=13.7, C33=8.11, C44=3.50, C12=4.82, C13=5.68, and C14=-2.00, in units of 1011 dyncm2. Independent checks of several of the elastic constants were made employing other directions and polarizations of the wave velocities. With the exception of C13, these values substantially agree with the data of Voigt and Bhimasenachar. ?? 1962 The American Institute of Physics.
Algorithm for structure constants
Paiva, F M
2011-01-01
In a $n$-dimensional Lie algebra, random numerical values are assigned by computer to $n(n-1)$ especially selected structure constants. An algorithm is then created, which calculates without ambiguity the remaining constants, obeying the Jacobi conditions. Differently from others, this algorithm is suitable even for poor personal computer. ------------- En $n$-dimensia algebro de Lie, hazardaj numeraj valoroj estas asignitaj per komputilo al $n(n-1)$ speciale elektitaj konstantoj de strukturo. Tiam algoritmo estas kreita, kalkulante senambigue la ceterajn konstantojn, obeante kondicxojn de Jacobi. Malsimile al aliaj algoritmoj, tiu cxi tauxgas ecx por malpotenca komputilo.
Radiographic constant exposure technique
DEFF Research Database (Denmark)
Domanus, Joseph Czeslaw
1985-01-01
The constant exposure technique has been applied to assess various industrial radiographic systems. Different X-ray films and radiographic papers of two producers were compared. Special attention was given to fast film and paper used with fluorometallic screens. Radiographic image quality was tes...... was tested by the use of ISO wire IQI's and ASTM penetrameters used on Al and Fe test plates. Relative speed and reduction of kilovoltage obtained with the constant exposure technique were calculated. The advantages of fast radiographic systems are pointed out...
Indian Academy of Sciences (India)
IAS Admin
electromagnetic force between subatomic charged parti- cles, and essentially determines how an atom holds to- gether its electrons. It is however not obvious why this constant has this ..... about α in 1948: “The theoretical interpretation of its numerical value is one of the most important unsolved problems of atomic physics.”
Gravitational constant calculation methodologies
Shakhparonov, V. M.; Karagioz, O. V.; Izmailov, V. P.
2011-01-01
We consider the gravitational constant calculation methodologies for a rectangular block of the torsion balance body presented in the papers Phys. Rev. Lett. 102, 240801 (2009) and Phys.Rev. D. 82, 022001 (2010). We have established the influence of non-equilibrium gas flows on the obtained values of G.
Directory of Open Access Journals (Sweden)
V. Prasannakumar
2012-03-01
Full Text Available A comprehensive methodology that integrates Revised Universal Soil Loss Equation (RUSLE model and Geographic Information System (GIS techniques was adopted to determine the soil erosion vulnerability of a forested mountainous sub-watershed in Kerala, India. The spatial pattern of annual soil erosion rate was obtained by integrating geo-environmental variables in a raster based GIS method. GIS data layers including, rainfall erosivity (R, soil erodability (K, slope length and steepness (LS, cover management (C and conservation practice (P factors were computed to determine their effects on average annual soil loss in the area. The resultant map of annual soil erosion shows a maximum soil loss of 17.73 t h-1 y-1 with a close relation to grass land areas, degraded forests and deciduous forests on the steep side-slopes (with high LS. The spatial erosion maps generated with RUSLE method and GIS can serve as effective inputs in deriving strategies for land planning and management in the environmentally sensitive mountainous areas.
Lager, Corey J; Esfandiari, Nazanene H; Subauste, Angela R; Kraftson, Andrew T; Brown, Morton B; Cassidy, Ruth B; Bellers, Darlene; Lockwood, Amy L; Varban, Oliver A; Oral, Elif A
2017-07-01
Rates of weight normalization and obesity remission after Roux-en-Y gastric bypass (GB) are unknown. This study evaluated weight loss, rates of achieving body mass index (BMI) weight and BMI at baseline, 2 and 6 months, and annually at 1-7 years in 219 patients undergoing GB at the University of Michigan from January 2008 to November 2010. Follow-up was excellent for a population traditionally associated with high attrition rates with data availability of 157/219, 145/219, 144/219, 134/219, 123/219, 82/161, and 29/64 patients at 1-7 years, respectively. Mean baseline BMI was 47.0 kg/m2. Weight normalization (BMI obesity (BMI weight normalization are low after GB; however, a large number of patients achieved BMI weight loss and excess weight loss are both quite high in the entire cohort and this is likely associated with significant health benefits, our results still underscore the need to address obesity with intensive clinical attention earlier in its course.
Tobia, Rajia C; Feldman, Jonquil D
2010-01-01
The setting for this case study is the Dolph Briscoe, Jr. Library, University of Texas Health Science Center at San Antonio, a health sciences campus with medical, dental, nursing, health professions, and graduate schools. During 2008-2009, major renovations to the library building were completed including office space for a faculty development department, multipurpose classrooms, a 24/7 study area, study rooms, library staff office space, and an information commons. The impetus for changes to the library building was the decreasing need to house collections in an increasingly electronic environment, the need for office space for other departments, and growth of the student body. About 40% of the library building was remodeled or repurposed, with a loss of approximately 25% of the library's original space. Campus administration proposed changes to the library building, and librarians worked with administration, architects, and construction managers to seek renovation solutions that meshed with the library's educational mission.
... of bone loss. For men, a drop in testosterone as they age can cause bone loss. Your ... Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, ...
Wolf, Joseph A
2010-01-01
This book is the sixth edition of the classic Spaces of Constant Curvature, first published in 1967, with the previous (fifth) edition published in 1984. It illustrates the high degree of interplay between group theory and geometry. The reader will benefit from the very concise treatments of riemannian and pseudo-riemannian manifolds and their curvatures, of the representation theory of finite groups, and of indications of recent progress in discrete subgroups of Lie groups. Part I is a brief introduction to differentiable manifolds, covering spaces, and riemannian and pseudo-riemannian geomet
Constant training in direct ophthalmoscopy
Directory of Open Access Journals (Sweden)
Younan HC
2017-08-01
Full Text Available Helen-Cara Younan, Rishi Iyer, Janaki Natasha DesaiFaculty of Medicine, Imperial College London, London, UKWe read with great interest the review by Ricci and Ferraz on the advances in training and practice in ophthalmoscopy simulation.1As final year medical students, we have recently experienced direct ophthalmoscopy teaching and agree with the authors that “simulation is a helpful tool in ophthalmoscopy training”.1 Indeed, in our experience, simulation is useful in teaching a wide variety of clinical skills including venepuncture, intravenous cannulation, and catheterization. We were taught all of these clinical skills in our first clinical year of study through use of simulation models. With regards to our direct ophthalmoscopy teaching, we were first taught to recognize the normal retina and different retinal pathologies using images, before practicing our technique and recognition of those images in a model similar to the THELMA (The Human Eye Learning Model Assistant described by the authors.1However, we feel that the use of simulation models alone is not enough to provide confidence and competency in direct ophthalmoscopy among medical students. The authors conclude that “constant training is a well-known strategy for skill enhancement”,1 and we have found that a lack of constant training in direct ophthalmoscopy is evident. After learning venepuncture, cannulation, and catheterization on the simulation models, we were able to observe doctors performing these skills before performing them on patients either in the wards or in theatre. These are skills that we are constantly trained in across a wide variety of medical and surgical attachments. However, opportunities to observe and practice ophthalmoscopy during our attachments are more limited, and thus we are not continuing to use the skills we learn.Authors' replyLucas Holderegger Ricci,1 Caroline Amaral Ferraz21Department of Ophthalmology, School of Medicine, Laureate
Producing the deuteron in stars: anthropic limits on fundamental constants
Barnes, Luke A.; Lewis, Geraint F.
2017-07-01
Stellar nucleosynthesis proceeds via the deuteron (D), but only a small change in the fundamental constants of nature is required to unbind it. Here, we investigate the effect of altering the binding energy of the deuteron on proton burning in stars. We find that the most definitive boundary in parameter space that divides probably life-permitting universes from probably life-prohibiting ones is between a bound and unbound deuteron. Due to neutrino losses, a ball of gas will undergo rapid cooling or stabilization by electron degeneracy pressure before it can form a stable, nuclear reaction-sustaining star. We also consider a less-bound deuteron, which changes the energetics of the pp and pep reactions. The transition to endothermic pp and pep reactions, and the resulting beta-decay instability of the deuteron, do not seem to present catastrophic problems for life.
Quantum Theory without Planck's Constant
Ralston, John P.
2012-01-01
Planck's constant was introduced as a fundamental scale in the early history of quantum mechanics. We find a modern approach where Planck's constant is absent: it is unobservable except as a constant of human convention. Despite long reference to experiment, review shows that Planck's constant cannot be obtained from the data of Ryberg, Davisson and Germer, Compton, or that used by Planck himself. In the new approach Planck's constant is tied to macroscopic conventions of Newtonian origin, wh...
Energy Technology Data Exchange (ETDEWEB)
Beiu, V.
1997-04-01
In this paper the authors discuss several complexity aspects pertaining to neural networks, commonly known as the curse of dimensionality. The focus will be on: (1) size complexity and depth-size tradeoffs; (2) complexity of learning; and (3) precision and limited interconnectivity. Results have been obtained for each of these problems when dealt with separately, but few things are known as to the links among them. They start by presenting known results and try to establish connections between them. These show that they are facing very difficult problems--exponential growth in either space (i.e. precision and size) and/or time (i.e., learning and depth)--when resorting to neural networks for solving general problems. The paper will present a solution for lowering some constants, by playing on the depth-size tradeoff.
Ozsoy, Gokhan; Aksoy, Ertugrul; Dirim, M Sabri; Tumsavas, Zeynal
2012-10-01
Sediment transport from steep slopes and agricultural lands into the Uluabat Lake (a RAMSAR site) by the Mustafakemalpasa (MKP) River is a serious problem within the river basin. Predictive erosion models are useful tools for evaluating soil erosion and establishing soil erosion management plans. The Revised Universal Soil Loss Equation (RUSLE) function is a commonly used erosion model for this purpose in Turkey and the rest of the world. This research integrates the RUSLE within a geographic information system environment to investigate the spatial distribution of annual soil loss potential in the MKP River Basin. The rainfall erosivity factor was developed from local annual precipitation data using a modified Fournier index: The topographic factor was developed from a digital elevation model; the K factor was determined from a combination of the soil map and the geological map; and the land cover factor was generated from Landsat-7 Enhanced Thematic Mapper (ETM) images. According to the model, the total soil loss potential of the MKP River Basin from erosion by water was 11,296,063 Mg year(-1) with an average soil loss of 11.2 Mg year(-1). The RUSLE produces only local erosion values and cannot be used to estimate the sediment yield for a watershed. To estimate the sediment yield, sediment-delivery ratio equations were used and compared with the sediment-monitoring reports of the Dolluk stream gauging station on the MKP River, which collected data for >41 years (1964-2005). This station observes the overall efficiency of the sediment yield coming from the Orhaneli and Emet Rivers. The measured sediment in the Emet and Orhaneli sub-basins is 1,082,010 Mg year(-1) and was estimated to be 1,640,947 Mg year(-1) for the same two sub-basins. The measured sediment yield of the gauge station is 127.6 Mg km(-2) year(-1) but was estimated to be 170.2 Mg km(-2) year(-1). The close match between the sediment amounts estimated using the RUSLE
The Cosmological Constant Problem (1/2)
CERN. Geneva
2015-01-01
I will review the cosmological constant problem as a serious challenge to our notion of naturalness in Physics. Weinberg’s no go theorem is worked through in detail. I review a number of proposals possibly including Linde's universe multiplication, Coleman's wormholes, the fat graviton, and SLED, to name a few. Large distance modifications of gravity are also discussed, with causality considerations pointing towards a global modification as being the most sensible option. The global nature of the cosmological constant problem is also emphasized, and as a result, the sequestering scenario is reviewed in some detail, demonstrating the cancellation of the Standard Model vacuum energy through a global modification of General Relativity.
The Cosmological Constant Problem (2/2)
CERN. Geneva
2015-01-01
I will review the cosmological constant problem as a serious challenge to our notion of naturalness in Physics. Weinberg’s no go theorem is worked through in detail. I review a number of proposals possibly including Linde's universe multiplication, Coleman's wormholes, the fat graviton, and SLED, to name a few. Large distance modifications of gravity are also discussed, with causality considerations pointing towards a global modification as being the most sensible option. The global nature of the cosmological constant problem is also emphasized, and as a result, the sequestering scenario is reviewed in some detail, demonstrating the cancellation of the Standard Model vacuum energy through a global modification of General Relativity.
Urakami, Shinji; Inoshita, Naoko; Oka, Suguru; Miyama, Yu; Nomura, Sachio; Arai, Masami; Sakaguchi, Kazushige; Kurosawa, Kazuhiro; Okaneya, Toshikazu
2017-11-22
To assess the detection rate of putative Lynch syndrome-associated upper urinary tract urothelial cancer among all upper urinary tract urothelial cancers and to examine its clinicopathological characteristics. A total of 143 patients with upper urinary tract urothelial cancer who had received total nephroureterectomy were immunohistochemically stained for the expression of mismatch repair proteins MLH1, PMS2, MSH2 and MSH6. For all suspected mismatch repair-deficient cases, MMR genetic testing was recommended and clinicopathological features were examined. Loss of mismatch repair proteins was found in seven patients (5%) who were thus categorized as putative Lynch syndrome-associated upper urinary tract urothelial cancer. Five of these patients showed dual loss of MSH2/MSH6. Two patients were confirmed to be MSH2 germline mutation carriers. Histologically, all seven tumors were low-grade atypical urothelial carcinoma and showed its unique histological features, such as an inverted papilloma-like growth pattern and a villous to papillary structure with mild stratification of tumor cells. Six tumors had no invasion of the muscularis propria. No recurrence or cancer-related deaths were reported in these seven patients. Just three patients met the revised Amsterdam criteria. This is the first report that universally examined mismatch repair immunohistochemical screening for upper urinary tract urothelial cancers. The prevalence (5%) of putative Lynch syndrome-associated upper urinary tract urothelial cancers is much higher than we had expected. We ascertained that putative Lynch syndrome-associated upper urinary tract urothelial cancers were clinically in the early stage and histologically classified into low-grade malignancy with its characteristic pathological features. The clinicopathological characteristics that we found in the present study could become additional possible markers in the diagnosis of Lynch syndrome-associated upper urinary tract urothelial cancers
Efficient Determination of Reverberation Chamber Time Constant
Zhang, Xiaotian; Robinson, Martin P.; Flintoft, Ian D.; Dawson, John F.
2017-01-01
Determination of the rate of energy loss in a reverberation chamber is fundamental to many different measurements such as absorption cross-section, antenna efficiency, radiated power, and shielding effectiveness. Determination of the energy decay time-constant in the time domain by linear fitting the power delay profile, rather than using the frequency domain quality-factor, has the advantage of being independent of the radiation efficiency of antennas used in the measurement. However, determ...
Pham Gia, Tung; Degener, Jan; Kappas, Martin
2017-04-01
The study was conducted in Asap river basin, A Luoi district, Thua Thien Hue Province, Vietnam, using the Universal Soil Loss Equation (USLE) and Geographical Information System (GIS) to determine the soil erosion status. The results show strong effect of the heavy rainfall and high slope on the erosion level in the research area. More than 40% of land area lost over 10 tons/ha/year. The natural forest land lost the most by averagely is 38.4 tons/ha/year, while the agricultural land showed less with 2.79 tons for paddy rice land use type and 7.58 tons for upland crops yearly. Comparison between some places of Vietnam and the Southeast Asia showed that soil erosion in watersheds of Asap is more serious. We have been proposed a recommendation on changing the classification system of land use type in Vietnam for more accurate in soil erosion measurement. Keywords: Land use type, Soil erosion, USLE, Central Vietnam.
The time dependence of fundamental constants
Energy Technology Data Exchange (ETDEWEB)
Udem, Thomas [Max-Planck Institut fuer Quantenoptik, Garching (Germany)
2008-07-01
Since Webb et al. have detected a slightly smaller fine structure constant by quasar absorption spectra about 10 billion years ago an old idea of P.A.M. Dirac from 1937 was revived. Using arguments philosophical in nature he speculated that fundamental constants should vary along with the expanding universe. For a long time the only possibility to search for these minute changes was to exploit the large look-back time of astronomical or geological observations. With the advent of frequency combs the possibility to check for these time variations in the laboratory with optical transitions in atoms, ions and molecules became readily available. Even though the time period covered by these laboratory measurements is typically 10 orders of magnitude shorter than for astronomical observations, they can be 10 orders of magnitude more accurate to provide comparable sensitivity. The question of the time dependence of fundamental constants is of high relevance in the context of modern cosmological models.
Disturbing Implications of a Cosmological Constant
Dyson, Lisa; Kleban, Matthew; Susskind, Leonard
2002-10-01
In this paper we consider the implications of a cosmological constant for the evolution of the universe, under a set of assumptions motivated by the holographic and horizon complementarity principles. We discuss the ``causal patch'' description of spacetime required by this framework, and present some simple examples of cosmologies described this way. We argue that these assumptions inevitably lead to very deep paradoxes, which seem to require major revisions of our usual assumptions.
Gravitation, the Quantum, and Cosmological Constant
Mazur, Pawel O.
1996-01-01
The arguments of statistical nature for the existence of constituents of active gravitational masses are presented. The present paper proposes a basis for microscopic theory of universal gravitation. Questions like the relation of cosmological constant and quantum theory, black hole radiance and the nature of inertia are addressed. This paper is the second in the series of papers published in Acta Physica Polonica {\\bf B}.
Determination of Biological Oxygen Demand Rate Constant and ...
African Journals Online (AJOL)
Determination of Biological Oxygen Demand Rate Constant and Ultimate Biological Oxygen Demand for Liquid Waste Generated from Student Cafeteria at Jimma University: A Tool for Development of Scientific Criteria to Protect Aquatic Health in the Region.
Cosmological Constant in the Thermodynamic Models of Gravity
Gogberashvili, Merab; Chutkerashvili, Ucha
2016-01-01
Within thermodynamic models of gravity, where the universe is considered as a finite ensemble of quantum particles, cosmological constant in the Einstein's equations appears as a constant of integration. Then it can be bounded using Karolyhazy uncertainty relation applied for horizon distances, as the amount of information in principle accessible to an external observer.
THE STABILITY CONSTANTS OF NICKEL (II) COMPLEXES OF ...
African Journals Online (AJOL)
DR. AMINU
2010-06-01
Jun 1, 2010 ... THE STABILITY CONSTANTS OF NICKEL (II) COMPLEXES OF AMINO ACIDS. WITH POLAR UNCHARGED R – GROUPS. Na'aliya, J. Department of Pure and Industrial Chemistry, Bayero University Kano, P. M. B. 3011, Kano, Nigeria jnaaliya@yahoo.com. ABSTRACT. The dissociation constant,pKa of ...
Energy Technology Data Exchange (ETDEWEB)
Laasonen, M.; Lahtinen, M.; Lustre, L.
1996-11-01
The greatest power losses in electricity transmission arise through a phenomenon called load losses. Corona losses caused by the surface discharge of electricity also constitute a considerable cost item. IVS, the nationwide network company, is investigating corona- induced losses, and has also commissioned similar research from IVO International, the Technical Research Centre of Finland (VTT) and from Tampere University of Technology. The research work strives to gain more in-depth knowledge on the phenomenon of frosting and its impact on corona losses. The correct prediction of frost helps reduce corona losses, while also cutting costs considerably. (orig.)
Spectrophotometric determination of association constant
DEFF Research Database (Denmark)
2016-01-01
Least-squares 'Systematic Trial-and-Error Procedure' (STEP) for spectrophotometric evaluation of association constant (equilibrium constant) K and molar absorption coefficient E for a 1:1 molecular complex, A + B = C, with error analysis according to Conrow et al. (1964). An analysis of the Charge...
Effective cosmological constant induced by stochastic fluctuations of Newton's constant
Energy Technology Data Exchange (ETDEWEB)
Cesare, Marco de, E-mail: marco.de_cesare@kcl.ac.uk [Department of Physics, King' s College London, University of London, London (United Kingdom); Lizzi, Fedele, E-mail: fedele.lizzi@na.infn.it [Dipartimento di Fisica “E. Pancini”, Università di Napoli “Federico II”, Napoli (Italy); INFN, Sezione di Napoli (Italy); Departament de Estructura i Constituents de la Matèria, Institut de Ciéncies del Cosmos, Universitat de Barcelona (Spain); Sakellariadou, Mairi, E-mail: mairi.sakellariadou@kcl.ac.uk [Department of Physics, King' s College London, University of London, London (United Kingdom)
2016-09-10
We consider implications of the microscopic dynamics of spacetime for the evolution of cosmological models. We argue that quantum geometry effects may lead to stochastic fluctuations of the gravitational constant, which is thus considered as a macroscopic effective dynamical quantity. Consistency with Riemannian geometry entails the presence of a time-dependent dark energy term in the modified field equations, which can be expressed in terms of the dynamical gravitational constant. We suggest that the late-time accelerated expansion of the Universe may be ascribed to quantum fluctuations in the geometry of spacetime rather than the vacuum energy from the matter sector.
Rusydy, I.; Faustino-Eslava, D. V.; Muksin, U.; Gallardo-Zafra, R.; Aguirre, J. J. C.; Bantayan, N. C.; Alam, L.; Dakey, S.
2017-02-01
Study on seismic hazard, building vulnerability and human loss assessment become substantial for building education institutions since the building are used by a lot of students, lecturers, researchers, and guests. The University of the Philippines, Los Banos (UPLB) located in an earthquake prone area. The earthquake could cause structural damage and injury of the UPLB community. We have conducted earthquake assessment in different magnitude and time to predict the posibility of ground shaking, building vulnerability and estimated the number of casualty of the UPLB community. The data preparation in this study includes the earthquake scenario modeling using Intensity Prediction Equations (IPEs) for shallow crustal shaking attenuation to produce intensity map of bedrock and surface. Earthquake model was generated from the segment IV and the segment X of the Valley Fault System (VFS). Building vulnerability of different type of building was calculated using fragility curve of the Philippines building. The population data for each building in various occupancy time, damage ratio, and injury ratio data were used to compute the number of casualties. The result reveals that earthquake model from the segment IV and the segment X of the VFS could generate earthquake intensity between 7.6 - 8.1 MMI in the UPLB campus. The 7.7 Mw earthquake (scenario I) from the segment IV could cause 32% - 51% damage of building and 6.5 Mw earthquake (scenario II) occurring in the segment X could cause 18% - 39% structural damage of UPLB buildings. If the earthquake occurs at 2 PM (day-time), it could injure 10.2% - 18.8% for the scenario I and could injure 7.2% - 15.6% of UPLB population in scenario II. The 5 Pm event, predicted will injure 5.1%-9.4% in the scenario I, and 3.6%-7.8% in scenario II. A nighttime event (2 Am) cause injury to students and guests who stay in dormitories. The earthquake is predicted to injure 13 - 66 students and guests in the scenario I and 9 - 47 people in the
Daylight calculations using constant luminance curves
Energy Technology Data Exchange (ETDEWEB)
Betman, E. [CRICYT, Mendoza (Argentina). Laboratorio de Ambiente Humano y Vivienda
2005-02-01
This paper presents a simple method to manually estimate daylight availability and to make daylight calculations using constant luminance curves calculated with local illuminance and irradiance data and the all-weather model for sky luminance distribution developed in the Atmospheric Science Research Center of the University of New York (ARSC) by Richard Perez et al. Work with constant luminance curves has the advantage that daylight calculations include the problem's directionality and preserve the information of the luminous climate of the place. This permits accurate knowledge of the resource and a strong basis to establish conclusions concerning topics related to the energy efficiency and comfort in buildings. The characteristics of the proposed method are compared with the method that uses the daylight factor. (author)
Decreased hearing; Deafness; Loss of hearing; Conductive hearing loss; Sensorineural hearing loss; Presbycusis ... Symptoms of hearing loss may include: Certain sounds seeming too loud Difficulty following conversations when two or more people are talking ...
Lepton Collider Operation with Constant Currents
Wienands, Ulrich
2005-01-01
Traditionally, electron-positron colliders have been operating in a top-off-and-coast fashion with a cycle time depending on the beam life time, typically on the order of an hour. Each top-off involves ramping detector systems in addition to the actual filling time. The loss in accumulated luminosity is typically 20-50%. During the last year, both B-Factories have commissioned a continuous-injection mode of operation in which beam is injected without ramping the detector, thus raising luminosity integration by constant operation at peak luminosity. Constant beam currents reduce thermal drift and trips caused by change in beam loading. To achieve this level of operation, special efforts were made to reduce the injection losses and also to implement special gating procedures in the detectors, minimizing dead time. Bunch-injection control decides which bunch to inject into next while maintaining small charge variation between bunches. Beam collimation can reduce injection noise but also cause an increase in back...
Learning Read-constant Polynomials of Constant Degree modulo Composites
DEFF Research Database (Denmark)
Chattopadhyay, Arkadev; Gavaldá, Richard; Hansen, Kristoffer Arnsfelt
2011-01-01
Boolean functions that have constant degree polynomial representation over a fixed finite ring form a natural and strict subclass of the complexity class \\textACC0ACC0. They are also precisely the functions computable efficiently by programs over fixed and finite nilpotent groups. This class...... is not known to be learnable in any reasonable learning model. In this paper, we provide a deterministic polynomial time algorithm for learning Boolean functions represented by polynomials of constant degree over arbitrary finite rings from membership queries, with the additional constraint that each variable...... in the target polynomial appears in a constant number of monomials. Our algorithm extends to superconstant but low degree polynomials and still runs in quasipolynomial time....
Emergent gravity in spaces of constant curvature
Alvarez, Orlando; Haddad, Matthew
2017-03-01
In physical theories where the energy (action) is localized near a submanifold of a constant curvature space, there is a universal expression for the energy (or the action). We derive a multipole expansion for the energy that has a finite number of terms, and depends on intrinsic geometric invariants of the submanifold and extrinsic invariants of the embedding of the submanifold. This is the second of a pair of articles in which we try to develop a theory of emergent gravity arising from the embedding of a submanifold into an ambient space equipped with a quantum field theory. Our theoretical method requires a generalization of a formula due to by Hermann Weyl. While the first paper discussed the framework in Euclidean (Minkowski) space, here we discuss how this framework generalizes to spaces of constant sectional curvature. We focus primarily on anti de Sitter space. We then discuss how such a theory can give rise to a cosmological constant and Planck mass that are within reasonable bounds of the experimental values.
Emergent gravity in spaces of constant curvature
Energy Technology Data Exchange (ETDEWEB)
Alvarez, Orlando; Haddad, Matthew [Department of Physics, University of Miami,1320 Campo Sano Ave, Coral Gables, FL 33146 (United States)
2017-03-07
In physical theories where the energy (action) is localized near a submanifold of a constant curvature space, there is a universal expression for the energy (or the action). We derive a multipole expansion for the energy that has a finite number of terms, and depends on intrinsic geometric invariants of the submanifold and extrinsic invariants of the embedding of the submanifold. This is the second of a pair of articles in which we try to develop a theory of emergent gravity arising from the embedding of a submanifold into an ambient space equipped with a quantum field theory. Our theoretical method requires a generalization of a formula due to by Hermann Weyl. While the first paper discussed the framework in Euclidean (Minkowski) space, here we discuss how this framework generalizes to spaces of constant sectional curvature. We focus primarily on anti de Sitter space. We then discuss how such a theory can give rise to a cosmological constant and Planck mass that are within reasonable bounds of the experimental values.
Systematics of constant roll inflation
Anguelova, Lilia; Suranyi, Peter; Wijewardhana, L. C. R.
2018-02-01
We study constant roll inflation systematically. This is a regime, in which the slow roll approximation can be violated. It has long been thought that this approximation is necessary for agreement with observations. However, recently it was understood that there can be inflationary models with a constant, and not necessarily small, rate of roll that are both stable and compatible with the observational constraint ns ≈ 1. We investigate systematically the condition for such a constant-roll regime. In the process, we find a whole new class of inflationary models, in addition to the known solutions. We show that the new models are stable under scalar perturbations. Finally, we find a part of their parameter space, in which they produce a nearly scale-invariant scalar power spectrum, as needed for observational viability.
Energy Technology Data Exchange (ETDEWEB)
Nez, F
2005-06-15
This document reviews the theoretical and experimental achievements of the author since the beginning of his scientific career. This document is dedicated to the spectroscopy of hydrogen, deuterium and helium atoms. The first part is divided into 6 sub-sections: 1) the principles of hydrogen spectroscopy, 2) the measurement of the 2S-nS/nD transitions, 3) other optical frequency measurements, 4) our contribution to the determination of the Rydberg constant, 5) our current experiment on the 1S-3S transition, 6) the spectroscopy of the muonic hydrogen. Our experiments have improved the accuracy of the Rydberg Constant by a factor 25 in 15 years and we have achieved the first absolute optical frequency measurement of a transition in hydrogen. The second part is dedicated to the measurement of the fine structure constant and the last part deals with helium spectroscopy and the search for optical references in the near infrared range. (A.C.)
Mirror QCD and Cosmological Constant
Directory of Open Access Journals (Sweden)
Roman Pasechnik
2017-05-01
Full Text Available An analog of Quantum Chromo Dynamics (QCD sector known as mirror QCD (mQCD can affect the cosmological evolution due to a non-trivial contribution to the Cosmological Constant analogous to that induced by the ground state in non-perturbative QCD. In this work, we explore a plausible hypothesis for trace anomalies cancellation between the usual QCD and mQCD. Such an anomaly cancellation between the two gauge theories, if it exists in Nature, would lead to a suppression or even elimination of their contributions to the Cosmological Constant. The trace anomaly compensation condition and the form of the non-perturbative mQCD coupling constant in the infrared limit have been proposed by analysing a partial non-perturbative solution of the Einstein–Yang-Mills equations of motion.
Tunnelling with a negative cosmological constant
Gibbons, G. W.
1996-02-01
The point of this paper is to see what light new results in hyperbolic geometry may throw on gravitational entropy and whether gravitational entropy is relevant for the quantum origin of the universe. We introduce some new gravitational instantons which mediate the birth from nothing of closed universes containing wormholes and suggest that they may contribute to the density matrix of the universe. We also discuss the connection between their gravitational action and the topological and volumetric entropies introduced in hyperbolic geometry. These coincide for hyperbolic 4-manifolds, and increase with increasing topological complexity of the 4-manifold. We raise the question of whether the action also increases with the topological complexity of the initial 3-geometry, measured either by its 3-volume or its Matveev complexity. We point out, in distinction to the non-supergravity case, that universes with domains of negative cosmological constant separated by supergravity domain walls cannot be born from nothing. Finally we point out that our wormholes provide examples of the type of Perpetual Motion machines envisaged by Frolov and Novikov.
Local Inhomogeneities and the Value of the Cosmological Constant
Romano, Antonio Enea
2013-12-01
Supernovae observations strongly support the presence of a cosmological constant, but its value, which we will call apparent, is normally determined assuming that the Universe can be accurately described by a homogeneous model. Even in the presence of a cosmological constant we cannot exclude nevertheless the presence of a small local inho-mogeneity which could affect the apparent value of the cosmological constant. Neglecting the presence of the inhomogeneity can in fact introduce a systematic misinterpretation of cosmological data, leading to the distinction between an apparent and the true value of the cosmological constant. But is such a difference distinguishable? Recently we set out to model the local inhomogeneity with a ΛLTB solution and computed the relation between the apparent and the true value of the cosmological constant. In this essay we reproduce the essence of our model with the emphasis on its physical implications.
Constant Proportion Debt Obligations (CPDOs)
DEFF Research Database (Denmark)
Cont, Rama; Jessen, Cathrine
2012-01-01
Constant Proportion Debt Obligations (CPDOs) are structured credit derivatives that generate high coupon payments by dynamically leveraging a position in an underlying portfolio of investment-grade index default swaps. CPDO coupons and principal notes received high initial credit ratings from...
GRAPHICAL DETERMINATION OF DISSOCIATION CONSTANT ...
African Journals Online (AJOL)
DR. AMINU
ABSTRACT. The dissociation constant (pKa) of non – polar amino acids including (alanine, glycine, valine phenylalanine and tryptophan) were determined by potentiometric titration technique. The pKa values obtained by extrapolation for alanine, glycine, and valine were 10.29, 9.87 and 9.91 respectively. The implications ...
GRAPHICAL DETERMINATION OF DISSOCIATION CONSTANT ...
African Journals Online (AJOL)
DR. AMINU
3: Plot of pH versus Log [HA]/[A-] for pKa of Valine. CONCLUSION. The acid dissociation constant of non polar amino acids determined graphically for the first time from the available literature were found to be similar with corresponding calculated values reported in the literature. Therefore the graphical approach is ...
Tanaka-Ouyang, Lei; Marlin, Sandrine; Nevoux, Jérôme
2017-11-01
Deafness is the most common sensory disability in developed countries affecting more than 2 births in 1000. Eighty percent of congenital deafness is genetic. Universal newborn hearing screening has been in place since 2012 in France. All genetic hearing losses are not congenital and all congenital hearing losses are not genetic. Genetic hearing loss may be syndromic (associated with other symptoms) (10 %) or non-syndromic (isolated) (90 %). Hearing loss may initially be the only symptom of syndromic deafness. A genetic origin can be diagnosed and must therefore be evoked systematically even in the adult. Copyright © 2017 Elsevier Masson SAS. All rights reserved.
Arfken, George
1984-01-01
University Physics provides an authoritative treatment of physics. This book discusses the linear motion with constant acceleration; addition and subtraction of vectors; uniform circular motion and simple harmonic motion; and electrostatic energy of a charged capacitor. The behavior of materials in a non-uniform magnetic field; application of Kirchhoff's junction rule; Lorentz transformations; and Bernoulli's equation are also deliberated. This text likewise covers the speed of electromagnetic waves; origins of quantum physics; neutron activation analysis; and interference of light. This publi
Effects of Cosmological Constant on Clustering of Galaxies
Hameeda, Mir; Faizal, Mir; Ali, Ahmed Farag
2016-01-01
In this paper, we analyse the effect of the expansion of the universe on the clustering of galaxies. We evaluate the configurational integral for interacting system of galaxies in an expanding universe by including effects produced by the cosmological constant. The gravitational partition function is obtained using this configuration integral. Thermodynamic quantities, specifically, Helmholtz free energy, entropy, internal energy, pressure and chemical potential are also derived for this system. It is observed that they depend on the modified clustering parameter for this system of galaxies. It is also demonstrated that these thermodynamical quantities get corrected because of the cosmological constant.
Wick, M C; Ernestam, S; Lindblad, S; Bratt, J; Klareskog, L; van Vollenhoven, R F
2005-01-01
To determine whether the tumour necrosis factor-alpha (TNF-alpha) antagonist adalimumab (Humira) can be efficacious after secondary loss of efficacy (i.e. loss of clinical response in patients who had initially demonstrated clinical response) to infliximab (Remicade) or etanercept (Enbrel). We studied 36 patients from the Stockholm TNF-alpha follow-up registry (STURE) who received adalimumab after secondary loss of efficacy to infliximab (group A, n = 27) or etanercept (group B, n = 9), and 26 patients who were started on adalimumab as the first TNF-alpha antagonist (group C). In group A, the baseline disease activity score 28 (DAS28) at infliximab institution was 5.5+/-0.2. During infliximab treatment, the mean best DAS28 was 3.7+/-0.2 (p<0.001), but increased to 5.2+/-0.3 when infliximab was stopped. After 3 months on adalimumab, the mean DAS28 decreased to 4.5+/-0.3 (p<0.003), and then to 4.2+/-0.2 at 6 months (p<0.001). In group B, the baseline DAS28 at etanercept institution was 6.6+/-0.5. During etanercept treatment, the mean best DAS28 was 4.6+/-0.5 (p<0.01), but increased to 5.7+/-0.4 by the time etanercept was stopped. After 3 months on adalimumab, the mean DAS28 decreased to 4.8+/-0.3 (p<0.005), and to 4.1+/-0.2 at 6 months (p<0.001). In group C, the mean baseline DAS28 was 5.6+/-0.3. After 6 months of adalimumab therapy, the DAS28 decreased to 3.5+/-0.4 (p<0.001). ACR20 responses with adalimumab in groups A, B, and C were similar (70-78%). For patients with secondary loss of efficacy from infliximab or etanercept, switching to adalimumab can restore a good clinical response.
Cosmological Constant and Local Gravity
Bernabeu, Jose; Mavromatos, Nick E
2010-01-01
We discuss the linearization of Einstein equations in the presence of a cosmological constant, by expanding the solution for the metric around a flat Minkowski space-time. We demonstrate that one can find consistent solutions to the linearized set of equations for the metric perturbations, in the Lorentz gauge, which are not spherically symmetric, but they rather exhibit a cylindrical symmetry. We find that the components of the gravitational field satisfying the appropriate Poisson equations have the property of ensuring that a scalar potential can be constructed, in which both contributions, from ordinary matter and $\\Lambda > 0$, are attractive. In addition, there is a novel tensor potential, induced by the pressure density, in which the effect of the cosmological constant is repulsive. We also linearize the Schwarzschild-de Sitter exact solution of Einstein's equations (due to a generalization of Birkhoff's theorem) in the domain between the two horizons. We manage to transform it first to a gauge in whic...
Searching for Kaprekar's constants: algorithms and results
Walden, Byron L.
2005-01-01
We examine some new results on Kaprekar's constants, specifically establishing the unique 7-digit (in base 4) and 9-digit (in base 5) Kaprekar's constants and showing that there are no 15-, 21-, 27-, or 33-digit Kaprekar's constants.
Positive Cosmological Constant and Quantum Theory
Directory of Open Access Journals (Sweden)
Felix M. Lev
2010-11-01
Full Text Available We argue that quantum theory should proceed not from a spacetime background but from a Lie algebra, which is treated as a symmetry algebra. Then the fact that the cosmological constant is positive means not that the spacetime background is curved but that the de Sitter (dS algebra as the symmetry algebra is more relevant than the Poincare or anti de Sitter ones. The physical interpretation of irreducible representations (IRs of the dS algebra is considerably different from that for the other two algebras. One IR of the dS algebra splits into independent IRs for a particle and its antiparticle only when Poincare approximation works with a high accuracy. Only in this case additive quantum numbers such as electric, baryon and lepton charges are conserved, while at early stages of the Universe they could not be conserved. Another property of IRs of the dS algebra is that only fermions can be elementary and there can be no neutral elementary particles. The cosmological repulsion is a simple kinematical consequence of dS symmetry on quantum level when quasiclassical approximation is valid. Therefore the cosmological constant problem does not exist and there is no need to involve dark energy or other fields for explaining this phenomenon (in agreement with a similar conclusion by Bianchi and Rovelli.
Hyperscaling violation and the shear diffusion constant
Directory of Open Access Journals (Sweden)
Kedar S. Kolekar
2016-09-01
Full Text Available We consider holographic theories in bulk (d+1-dimensions with Lifshitz and hyperscaling violating exponents z,θ at finite temperature. By studying shear gravitational modes in the near-horizon region given certain self-consistent approximations, we obtain the corresponding shear diffusion constant on an appropriately defined stretched horizon, adapting the analysis of Kovtun, Son and Starinets. For generic exponents with d−z−θ>−1, we find that the diffusion constant has power law scaling with the temperature, motivating us to guess a universal relation for the viscosity bound. When the exponents satisfy d−z−θ=−1, we find logarithmic behaviour. This relation is equivalent to z=2+deff where deff=di−θ is the effective boundary spatial dimension (and di=d−1 the actual spatial dimension. It is satisfied by the exponents in hyperscaling violating theories arising from null reductions of highly boosted black branes, and we comment on the corresponding analysis in that context.
Is cosmological constant needed in Higgs inflation?
Directory of Open Access Journals (Sweden)
Chao-Jun Feng
2014-11-01
Full Text Available The detection of B-mode shows a very powerful constraint to theoretical inflation models through the measurement of the tensor-to-scalar ratio r. Higgs boson is the most likely candidate of the inflaton field. But usually, Higgs inflation models predict a small value of r, which is not quite consistent with the recent results from BICEP2. In this paper, we explored whether a cosmological constant energy component is needed to improve the situation. And we found the answer is yes. For the so-called Higgs chaotic inflation model with a quadratic potential, it predicts r≈0.2, ns≈0.96 with e-folds number N≈56, which is large enough to overcome the problems such as the horizon problem in the Big Bang cosmology. The required energy scale of the cosmological constant is roughly Λ∼(1014 GeV2, which means a mechanism is still needed to solve the fine-tuning problem in the later time evolution of the universe, e.g. by introducing some dark energy component.
Higgs inflation and the cosmological constant
Energy Technology Data Exchange (ETDEWEB)
Jegerlehner, Fred [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2014-02-15
The Higgs not only induces the masses of all SM particles, the Higgs, given its special mass value, is the natural candidate for the inflaton and in fact is ruling the evolution of the early universe, by providing the necessary dark energy which remains the dominant energy density. SM running couplings not only allow us to extrapolate SM physics up to the Planck scale, but equally important they are triggering the Higgs mechanism. This is possible by the fact that the bare mass term in the Higgs potential changes sign at about μ{sub 0}≅1.40 x 10{sup 16} GeV and in the symmetric phase is enhanced by quadratic terms in the Planck mass. Such a huge Higgs mass term is able to play a key role in triggering inflation in the early universe. In this article we extend our previous investigation by working out the details of a Higgs inflation scenario. We show how different terms contributing to the Higgs Lagrangian are affecting inflation. Given the SM and its extrapolation to scales μ>μ{sub 0} we find a calculable cosmological constant V(0) which is weakly scale dependent and actually remains large during inflation. This is different to the Higgs fluctuation field dependent ΔV(φ), which decays exponentially during inflation, and actually would not provide a sufficient amount of inflation. The fluctuation field has a different effective mass which shifts the bare Higgs transition point to a lower value μ'{sub 0} ≅7.7 x 10{sup 14} GeV. The vacuum energy V(0) being proportional to M{sub Pl}{sup 4} has a coefficient which vanishes near the Higgs transition point, such that the bare and the renormalized cosmological constant match at this point. The role of the Higgs in reheating and baryogenesis is emphasized.
Exact constants in approximation theory
Korneichuk, N
1991-01-01
This book is intended as a self-contained introduction for non-specialists, or as a reference work for experts, to the particular area of approximation theory that is concerned with exact constants. The results apply mainly to extremal problems in approximation theory, which in turn are closely related to numerical analysis and optimization. The book encompasses a wide range of questions and problems: best approximation by polynomials and splines; linear approximation methods, such as spline-approximation; optimal reconstruction of functions and linear functionals. Many of the results are base
Cryptography in constant parallel time
Applebaum, Benny
2013-01-01
Locally computable (NC0) functions are 'simple' functions for which every bit of the output can be computed by reading a small number of bits of their input. The study of locally computable cryptography attempts to construct cryptographic functions that achieve this strong notion of simplicity and simultaneously provide a high level of security. Such constructions are highly parallelizable and they can be realized by Boolean circuits of constant depth.This book establishes, for the first time, the possibility of local implementations for many basic cryptographic primitives such as one-way func
Dark Energy and the Cosmological Constant: A Brief Introduction
Harvey, Alex
2009-01-01
The recently observed acceleration of the expansion of the universe is a topic of intense interest. The favoured causes are the "cosmological constant" or "dark energy". The former, which appears in the Einstein equations as the term [lambda]g[subscript [mu]v], provides an extremely simple, well-defined mechanism for the acceleration. However,…
The Cosmological Constant Problem, an Inspiration for New Physics
Nobbenhuis, Stefanus Johannes Bernardus
2006-01-01
We have critically compared different approaches to the cosmological constant problem, which is at the edge of elementary particle physics and cosmology. This problem is deeply connected with the difficulties formulating a theory of quantum gravity. After the 1998 discovery that our universe's
$AdS_{5}$ and the 4D Cosmological Constant
Schmidhuber, C
2000-01-01
The hypothesis is discussed that our universe is really 5-dimensional with a nonzero cosmological constant that produces a large negative curvature. In this scenario, the observable flat 4-dimensional world is identified with the holographic projection of the 5-dimensional world onto its own boundary. (21 refs).
... amnesia (sudden, temporary loss of memory) of unclear cause Transient ischemic attack (TIA) or stroke Hydrocephalus (fluid collection in the brain) Sometimes, memory loss occurs with mental health problems, such as: After a major, traumatic or stressful ...
... overall hair thinning and not bald patches. Full-body hair loss. Some conditions and medical treatments, such as ... in the loss of hair all over your body. The hair usually grows back. Patches of scaling that spread ...
Formas estructurales de fuerza constante
Directory of Open Access Journals (Sweden)
Zalewski, Waclaw
1963-05-01
Full Text Available The author seeks to prove the need to obtain the most essential form in the various types of structures by applying a number of rational principles, of which the constant stress principle is one of the most decisive. The structural form should be a logical consequence of all its functional circumstances, and this requires a clear understanding of the general behaviour of each part of the structure, and also of the main stresses which operate on it, considered as a unitary whole. To complete his theoretical argument, the author gives some examples, in the design of which the criterion of constant stress has been adopted. The author considers the various aspects which are involved in obtaining a structural design that satisfies given functional and aesthetic requirements. In doing so he refers to his personal experience within Poland, and infers technical principles of general validity which should determine the rational design of the form, as an integrated aspect of the structural pattern. The projects which illustrate this paper are Polish designs of undoubted constructive significance, in which the principle of constant stress has been applied. Finally the author condenses his whole theory in a simple and straightforward practical formula, which should be followed if a truly rational form is to be achieved: the constancy of stress in the various structural elements.El autor se esfuerza en mostrar la necesidad de llegar a la forma real en las distintas estructuras siguiendo una serie de principios racionales, entre los que domina el criterio de la fuerza constante. La forma ha de ser una consecuencia lógica en todos sus aspectos, y esto exige un claro conocimiento del comportamiento general de cada una de las partes de la estructura, y de los esfuerzos generales que dominan en la misma al considerarla como un todo. Para completar la exposición de orden teórico, el autor presenta algunos ejemplos en cuyo proyecto se ha seguido el criterio de
(Krauss) at constant high temperatures
African Journals Online (AJOL)
Snail Research Unit of the SAMRC and Department of Zoology, Potchefstroom University for CHE,. Potchefstroom. The survival of the freshwater snail species Bulinus africanus, Bulinus g/obosus and Biompha/aria pfeifferi at extreme high temperatures was experimentally investigated. Snails were exposed to temperatures ...
Academic Freedom Requires Constant Vigilance
Emery, Kim
2009-01-01
Traditionally, academic freedom has been understood as an individual right and a negative liberty. As William Tierney and Vincente Lechuga explain, "Academic freedom, although an institutional concept, was vested in the individual professor." The touchstone document on academic freedom, the American Association of University Professor's (AAUP)…
Thibodeau, Patricia L
2010-01-01
The Duke University Medical Center Library and Archives is located in the heart of the Duke Medicine campus, surrounded by Duke Hospital, ambulatory clinics, and numerous research facilities. Its location is considered prime real estate, given its adjacency to patient care, research, and educational activities. In 2005, the Duke University Library Space Planning Committee had recommended creating a learning center in the library that would support a variety of educational activities. However, the health system needed to convert the library's top floor into office space to make way for expansion of the hospital and cancer center. The library had only five months to plan the storage and consolidation of its journal and book collections, while working with the facilities design office and architect on the replacement of key user spaces on the top floor. Library staff worked together to develop plans for storing, weeding, and consolidating the collections and provided input into renovation plans for users spaces on its mezzanine level. The library lost 15,238 square feet (29%) of its net assignable square footage and a total of 16,897 (30%) gross square feet. This included 50% of the total space allotted to collections and over 15% of user spaces. The top-floor space now houses offices for Duke Medicine oncology faculty and staff. By storing a large portion of its collection off-site, the library was able to remove more stacks on the remaining stack level and convert them to user spaces, a long-term goal for the library. Additional space on the mezzanine level had to be converted to replace lost study and conference room spaces. While this project did not match the recommended space plans for the library, it underscored the need for the library to think creatively about the future of its facility and to work toward a more cohesive master plan.
DEFF Research Database (Denmark)
Kristiansen, Maria; Younis, Tarek; Hassani, Amani
2015-01-01
, who narrates her experience of losing herhusband to lung cancer. By drawing on a religious framework, Aisha creates meaning fromher loss, which enables her to incorporate this loss into her life history and sustain agency.Her narrative invites wider audiences to witness her tale of overcoming loss...
van Dam, E.R.; Haemers, W.H.
1995-01-01
A graph G has constant u = u(G) if any two vertices that are not adjacent have u common neighbours. G has constant u and u if G has constant u = u(G), and its complement G has constant u = u(G). If such a graph is regular, then it is strongly regular, otherwise precisely two vertex degrees occur. We
Stability constant estimator user`s guide
Energy Technology Data Exchange (ETDEWEB)
Hay, B.P.; Castleton, K.J.; Rustad, J.R.
1996-12-01
The purpose of the Stability Constant Estimator (SCE) program is to estimate aqueous stability constants for 1:1 complexes of metal ions with ligands by using trends in existing stability constant data. Such estimates are useful to fill gaps in existing thermodynamic databases and to corroborate the accuracy of reported stability constant values.
Unaccounted source of systematic errors in measurements of the Newtonian gravitational constant G
Energy Technology Data Exchange (ETDEWEB)
DeSalvo, Riccardo, E-mail: Riccardo.desalvo@gmail.com [California State University, Northridge, 18111 Nordhoff Street, Northridge, CA 91330-8332 (United States); University of Sannio, Corso Garibaldi 107, Benevento 82100 (Italy)
2015-06-26
Many precision measurements of G have produced a spread of results incompatible with measurement errors. Clearly an unknown source of systematic errors is at work. It is proposed here that most of the discrepancies derive from subtle deviations from Hooke's law, caused by avalanches of entangled dislocations. The idea is supported by deviations from linearity reported by experimenters measuring G, similarly to what is observed, on a larger scale, in low-frequency spring oscillators. Some mitigating experimental apparatus modifications are suggested. - Highlights: • Source of discrepancies on universal gravitational constant G measurements. • Collective motion of dislocations results in breakdown of Hook's law. • Self-organized criticality produce non-predictive shifts of equilibrium point. • New dissipation mechanism different from loss angle and viscous models is necessary. • Mitigation measures proposed may bring coherence to the measurements of G.
Functionalised graphene sheets as effective high dielectric constant fillers
Directory of Open Access Journals (Sweden)
Romasanta Laura
2011-01-01
Full Text Available Abstract A new functionalised graphene sheet (FGS filled poly(dimethylsiloxane insulator nanocomposite has been developed with high dielectric constant, making it well suited for applications in flexible electronics. The dielectric permittivity increased tenfold at 10 Hz and 2 wt.% FGS, while preserving low dielectric losses and good mechanical properties. The presence of functional groups on the graphene sheet surface improved the compatibility nanofiller/polymer at the interface, reducing the polarisation process. This study demonstrates that functionalised graphene sheets are ideal nanofillers for the development of new polymer composites with high dielectric constant values. PACS: 78.20.Ci, 72.80.Tm, 62.23.Kn
The fundamental constants a mystery of physics
Fritzsch, Harald
2009-01-01
The speed of light, the fine structure constant, and Newton's constant of gravity — these are just three among the many physical constants that define our picture of the world. Where do they come from? Are they constant in time and across space? In this book, physicist and author Harald Fritzsch invites the reader to explore the mystery of the fundamental constants of physics in the company of Isaac Newton, Albert Einstein, and a modern-day physicist
Omnidirectional antenna having constant phase
Energy Technology Data Exchange (ETDEWEB)
Sena, Matthew
2017-04-04
Various technologies presented herein relate to constructing and/or operating an antenna having an omnidirectional electrical field of constant phase. The antenna comprises an upper plate made up of multiple conductive rings, a lower ground-plane plate, a plurality of grounding posts, a conical feed, and a radio frequency (RF) feed connector. The upper plate has a multi-ring configuration comprising a large outer ring and several smaller rings of equal size located within the outer ring. The large outer ring and the four smaller rings have the same cross-section. The grounding posts ground the upper plate to the lower plate while maintaining a required spacing/parallelism therebetween.
Henry's law constants of polyols
Compernolle, S.; Müller, J.-F.
2014-12-01
Henry's law constants (HLC) are derived for several polyols bearing between 2 and 6 hydroxyl groups, based on literature data for water activity, vapour pressure and/or solubility. While deriving HLC and depending on the case, also infinite dilution activity coefficients (IDACs), solid state vapour pressures or activity coefficient ratios are obtained as intermediate results. An error analysis on the intermediate quantities and the obtained HLC is included. For most compounds, these are the first values reported, while others compare favourably with literature data in most cases. Using these values and those from a previous work (Compernolle and Müller, 2014), an assessment is made on the partitioning of polyols, diacids and hydroxy acids to droplet and aqueous aerosol.
Henry's law constants of polyols
Directory of Open Access Journals (Sweden)
S. Compernolle
2014-12-01
Full Text Available Henry's law constants (HLC are derived for several polyols bearing between 2 and 6 hydroxyl groups, based on literature data for water activity, vapour pressure and/or solubility. While deriving HLC and depending on the case, also infinite dilution activity coefficients (IDACs, solid state vapour pressures or activity coefficient ratios are obtained as intermediate results. An error analysis on the intermediate quantities and the obtained HLC is included. For most compounds, these are the first values reported, while others compare favourably with literature data in most cases. Using these values and those from a previous work (Compernolle and Müller, 2014, an assessment is made on the partitioning of polyols, diacids and hydroxy acids to droplet and aqueous aerosol.
Philicities, Fugalities, and Equilibrium Constants.
Mayr, Herbert; Ofial, Armin R
2016-05-17
The mechanistic model of Organic Chemistry is based on relationships between rate and equilibrium constants. Thus, strong bases are generally considered to be good nucleophiles and poor nucleofuges. Exceptions to this rule have long been known, and the ability of iodide ions to catalyze nucleophilic substitutions, because they are good nucleophiles as well as good nucleofuges, is just a prominent example for exceptions from the general rule. In a reaction series, the Leffler-Hammond parameter α = δΔG(⧧)/δΔG° describes the fraction of the change in the Gibbs energy of reaction, which is reflected in the change of the Gibbs energy of activation. It has long been considered as a measure for the position of the transition state; thus, an α value close to 0 was associated with an early transition state, while an α value close to 1 was considered to be indicative of a late transition state. Bordwell's observation in 1969 that substituent variation in phenylnitromethanes has a larger effect on the rates of deprotonation than on the corresponding equilibrium constants (nitroalkane anomaly) triggered the breakdown of this interpretation. In the past, most systematic investigations of the relationships between rates and equilibria of organic reactions have dealt with proton transfer reactions, because only for few other reaction series complementary kinetic and thermodynamic data have been available. In this Account we report on a more general investigation of the relationships between Lewis basicities, nucleophilicities, and nucleofugalities as well as between Lewis acidities, electrophilicities, and electrofugalities. Definitions of these terms are summarized, and it is suggested to replace the hybrid terms "kinetic basicity" and "kinetic acidity" by "protophilicity" and "protofugality", respectively; in this way, the terms "acidity" and "basicity" are exclusively assigned to thermodynamic properties, while "philicity" and "fugality" refer to kinetics
Devaluation: a dynamical mechanism for a naturally small cosmological constant
Energy Technology Data Exchange (ETDEWEB)
Freese, Katherine [Michigan Center for Theoretical Physics, University of Michigan, Ann Arbor, MI 48109-1120 (United States)]. E-mail: ktfreese@umich.edu; Liu, James T. [Michigan Center for Theoretical Physics, University of Michigan, Ann Arbor, MI 48109-1120 (United States)]. E-mail: jimliu@umich.edu; Spolyar, Douglas [Physics Department, University of California, Santa Cruz, CA 95060 (United States)]. E-mail: dspolyar@physics.ucsc.edu
2006-03-09
We propose a natural solution to the cosmological constant problem consistent with the standard cosmology and successful over a broad range of energies. This solution is based on the existence of a new field, the devaluton, with its potential modeled on a tilted cosine. After inflation, the universe reheats and populates the devaluton's many minima. As the universe cools, domain walls form between different regions. The domain wall network then evolves and sweeps away regions of higher vacuum energy in favor of lower energy ones. Gravitation itself provides a cutoff at a minimum vacuum energy, thus leaving the universe with a small cosmological constant comparable in magnitude to the present day dark energy density.
Brane-world cosmic strings revive the cosmological constant
Heydari-Fard, M.; Razmi, H.; Rokni, S. Y.
2013-08-01
We obtain the static and cylindrically symmetric vacuum solutions of Einstein’s field equations in the framework of the brane-world model where the matter is localized on the brane by means of a confining potential. Considering a constant curvature bulk, one interesting solution is studied, which is similar to the cosmic string solution in a de Sitter spacetime which confirms the idea that the extra geometrical terms in the gravitational field equations on the brane may be the origin of a positive cosmological constant which is responsible for the accelerating expansion of the universe. Finally, we investigate the physical properties of this solution.
Density of Vacuum-Like Plasma and Hubble Constant
Obukhov, Ilya A.
2017-10-01
The model in which expansion of the Universe leads to a generation of non-equilibrium vacuum-like electron-positron plasma is proposed and researched. The formulas that relate the Hubble's constant with the concentration of plasma particles and the cosmological constant are obtained. The collective properties of vacuum-like plasma are investigated. It is shown, that the coefficient of a two-photon annihilation in such plasma is nine times less than for the free particles. A simple formula for dark energy density as a function of electron mass and charge is obtained. It was demonstrated that acceleration of plasma's chemical potential fluctuations flow proportional of dark energy density.
Arrhenius Rate: constant volume burn
Energy Technology Data Exchange (ETDEWEB)
Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-12-06
A constant volume burn occurs for an idealized initial state in which a large volume of reactants at rest is suddenly raised to a high temperature and begins to burn. Due to the uniform spatial state, there is no fluid motion and no heat conduction. This reduces the time evolu tion to an ODE for the reaction progress variable. With an Arrhenius reaction rate, two characteristics of thermal ignition are illustrated: induction time and thermal runaway. The Frank-Kamenetskii approximation then leads to a simple expression for the adiabatic induction time. For a first order reaction, the analytic solution is derived and used to illustrate the effect of varying the activation temperature; in particular, on the induction time. In general, the ODE can be solved numerically. This is used to illustrate the effect of varying the reaction order. We note that for a first order reaction, the time evolution of the reaction progress variable has an exponential tail. In contrast, for a reaction order less than one, the reaction completes in a nite time. The reaction order also affects the induction time.
Planck intermediate results. XXIV. Constraints on variation of fundamental constants
Ade, P A R; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A.J.; Barreiro, R.B.; Battaner, E.; Benabed, K.; Benoit-Levy, A.; Bernard, J.P.; Bersanelli, M.; Bielewicz, P.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Burigana, C.; Butler, R.C.; Calabrese, E.; Chamballu, A.; Chiang, H.C.; Christensen, P.R.; Clements, D.L.; Colombo, L.P.L.; Couchot, F.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; Davis, R.J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Diego, J.M.; Dole, H.; Dore, O.; Dupac, X.; Ensslin, T.A.; Eriksen, H.K.; Fabre, O.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Galeotta, S.; Galli, S.; Ganga, K.; Giard, M.; Gonzalez-Nuevo, J.; Gorski, K.M.; Gregorio, A.; Gruppuso, A.; Hansen, F.K.; Hanson, D.; Harrison, D.L.; Henrot-Versille, S.; Hernandez-Monteagudo, C.; Herranz, D.; Hildebrandt, S.R.; Hivon, E.; Hobson, M.; Holmes, W.A.; Hornstrup, A.; Hovest, W.; Huffenberger, K.M.; Jaffe, A.H.; Jones, W.C.; Keihanen, E.; Keskitalo, R.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lamarre, J.M.; Lasenby, A.; Lawrence, C.R.; Leonardi, R.; Lesgourgues, J.; Liguori, M.; Lilje, P.B.; Linden-Vornle, M.; Lopez-Caniego, M.; Lubin, P.M.; Macias-Perez, J.F.; Mandolesi, N.; Maris, M.; Martin, P.G.; Martinez-Gonzalez, E.; Masi, S.; Matarrese, S.; Mazzotta, P.; Meinhold, P.R.; Melchiorri, A.; Mendes, L.; Menegoni, E.; Mennella, A.; Migliaccio, M.; Miville-Deschenes, M.A.; Moneti, A.; Montier, L.; Morgante, G.; Moss, A.; Munshi, D.; Murphy, J.A.; Naselsky, P.; Nati, F.; Natoli, P.; Norgaard-Nielsen, H.U.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C.A.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Pratt, G.W.; Prunet, S.; Rachen, J.P.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Ristorcelli, I.; Rocha, G.; Roudier, G.; Rusholme, B.; Sandri, M.; Savini, G.; Scott, D.; Spencer, L.D.; Stolyarov, V.; Sudiwala, R.; Sutton, D.; Suur-Uski, A.S.; Sygnet, J.F.; Tauber, J.A.; Tavagnacco, D.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Uzan, J.P.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L.A.; Yvon, D.; Zacchei, A.; Zonca, A.
2015-01-01
Any variation of the fundamental physical constants, and more particularly of the fine structure constant, $\\alpha$, or of the mass of the electron, $m_e$, would affect the recombination history of the Universe and cause an imprint on the cosmic microwave background angular power spectra. We show that the Planck data allow one to improve the constraint on the time variation of the fine structure constant at redshift $z\\sim 10^3$ by about a factor of 5 compared to WMAP data, as well as to break the degeneracy with the Hubble constant, $H_0$. In addition to $\\alpha$, we can set a constraint on the variation of the mass of the electron, $m_{\\rm e}$, and on the simultaneous variation of the two constants. We examine in detail the degeneracies between fundamental constants and the cosmological parameters, in order to compare the limits obtained from Planck and WMAP and to determine the constraining power gained by including other cosmological probes. We conclude that independent time variations of the fine structu...
The fundamental constants and quantum electrodynamics
Taylor, Barry N; Langenberg, D N
1969-01-01
Introduction ; review of experimental data ; least-squares adjustment to obtain values of the constants without QED theory ; implications for quantum electrodynamics ; final recommended set of fundamental constants ; summary and conclusions.
Capacitive Cells for Dielectric Constant Measurement
Aguilar, Horacio Munguía; Maldonado, Rigoberto Franco
2015-01-01
A simple capacitive cell for dielectric constant measurement in liquids is presented. As an illustrative application, the cell is used for measuring the degradation of overheated edible oil through the evaluation of their dielectric constant.
ESR melting under constant voltage conditions
Energy Technology Data Exchange (ETDEWEB)
Schlienger, M.E.
1997-02-01
Typical industrial ESR melting practice includes operation at a constant current. This constant current operation is achieved through the use of a power supply whose output provides this constant current characteristic. Analysis of this melting mode indicates that the ESR process under conditions of constant current is inherently unstable. Analysis also indicates that ESR melting under the condition of a constant applied voltage yields a process which is inherently stable. This paper reviews the process stability arguments for both constant current and constant voltage operation. Explanations are given as to why there is a difference between the two modes of operation. Finally, constant voltage process considerations such as melt rate control, response to electrode anomalies and impact on solidification will be discussed.
Anderegg, G
2013-01-01
Critical Survey of Stability Constants of EDTA Complexes focuses on the computations, values, and characteristics of stability constants. The book emphasizes that for a critical discussion of experimentally determined stability constants, it is important to consider the precision of the values that manifests the self-consistency of the constant, taking into consideration the random errors. The publication reviews the stability constants of metal complexes. The numerical calculations affirm the reactions and transformations of metal ions when exposed to varying conditions. The text also present
Surprises in numerical expressions of physical constants
Amir, Ariel; Lemeshko, Mikhail; Tokieda, Tadashi
2016-01-01
In science, as in life, `surprises' can be adequately appreciated only in the presence of a null model, what we expect a priori. In physics, theories sometimes express the values of dimensionless physical constants as combinations of mathematical constants like pi or e. The inverse problem also arises, whereby the measured value of a physical constant admits a `surprisingly' simple approximation in terms of well-known mathematical constants. Can we estimate the probability for this to be a me...
Searching for Kaprekar's constants: algorithms and results
Directory of Open Access Journals (Sweden)
Byron L. Walden
2005-01-01
Full Text Available We examine some new results on Kaprekar's constants, specifically establishing the unique 7-digit (in base 4 and 9-digit (in base 5 Kaprekar's constants and showing that there are no 15-, 21-, 27-, or 33-digit Kaprekar's constants.
Untangling Fixed Effects and Constant Regressors
Klaassen, F.; Teulings, R.
2015-01-01
Fixed effects (FE) in panel data models overlap each other and prohibit the identification of the impact of "constant" regressors. Think of regressors that are constant across countries in a country-time panel with time FE. The traditional approach is to drop some FE and constant regressors by
Constant mortality and fertility over age in Hydra
DEFF Research Database (Denmark)
Schaible, R.; Scheuerlein, A.; Danko, M. J.
2015-01-01
, or remain constant with age, but the data are scanty and problematic. Here, we present compelling evidence for constant age-specific death and reproduction rates in Hydra, a basal metazoan, in a set of experiments comprising more than 3.9 million days of observations of individual Hydra. Our data show...... that 2,256 Hydra from two closely related species in two laboratories in 12 cohorts, with cohort age ranging from 0 to more than 41 y, have extremely low, constant rates of mortality. Fertility rates for Hydra did not systematically decline with advancing age. This falsifies the universality...... of the theories of the evolution of aging that posit that all species deteriorate with age after maturity. The nonsenescent life history of Hydra implies levels of maintenance and repair that are sufficient to prevent the accumulation of damage for at least decades after maturity, far longer than the short life...
Non-minimally coupled varying constants quantum cosmologies
Balcerzak, Adam
2015-01-01
We consider gravity theory with varying speed of light and varying gravitational constant. Both constants are represented by non-minimally coupled scalar fields. We examine the cosmological evolution in the near curvature singularity regime. We find that at the curvature singularity the speed of light goes to infinity while the gravitational constant vanishes. This corresponds to the Newton's Mechanics limit represented by one of the vertex of the Bronshtein-Zelmanov-Okun cube. The cosmological evolution includes both the pre-big-bang and post-big-bang phases separated by the curvature singularity. We also investigate the quantum counterpart of the considered theory and find the probability of transition of the universe from the collapsing pre-big-bang phase to the expanding post-big-bang phase.
Non-minimally coupled varying constants quantum cosmologies
Balcerzak, Adam
2015-04-01
We consider gravity theory with varying speed of light and varying gravitational constant. Both constants are represented by non-minimally coupled scalar fields. We examine the cosmological evolution in the near curvature singularity regime. We find that at the curvature singularity the speed of light goes to infinity while the gravitational constant vanishes. This corresponds to the Newton's Mechanics limit represented by one of the vertex of the Bronshtein-Zelmanov-Okun cube [1,2]. The cosmological evolution includes both the pre-big-bang and post-big-bang phases separated by the curvature singularity. We also investigate the quantum counterpart of the considered theory and find the probability of transition of the universe from the collapsing pre-big-bang phase to the expanding post-big-bang phase.
Cosmological Consequences of a Variable Cosmological Constant Model
Azri, Hemza
2014-01-01
We derive a model of dark energy which evolves with time via the scale factor. The equation of state $\\omega=(1-2\\alpha)/(1+2\\alpha)$ is studied as a function of a parameter $\\alpha$ introduced in this model. In addition to the recent accelerated expansion, the model predicts another decelerated phase. The age of the universe is found to be almost consistent with observation. In the limiting case, the cosmological constant model, we find that vacuum energy gravitates with a tiny gravitational constant which evolves with the scale factor, rather than with Newton's constant. This enables degravitation of the vacuum energy which in turn produces the tiny observed curvature, rather than a 120 orders of magnitude larger value.
More on lensing by a cosmological constant
Ishak, M.; Rindler, W.; Dossett, J.
2010-04-01
The question of whether or not the cosmological constant affects the bending of light around a concentrated mass has been the subject of some recent papers. We present here a simple, specific and transparent example where Λ bending clearly takes place, and where it is clearly neither a coordinate effect nor an aberration effect. We then show that in some recent works using perturbation theory the Λ contribution was missed because of initial too stringent smallness assumptions. Namely, our method has been to insert a Kottler (Schwarzschild with Λ) vacuole into a Friedmann universe, and to calculate the total bending within the vacuole. We assume that no more bending occurs outside. It is important to observe that while the mass contribution to the bending takes place mainly quite near the lens, the Λ bending continues throughout the vacuole. Thus, if one deliberately restricts one's search for Λ bending to the immediate neighbourhood of the lens, one will not find it. Lastly, we show that the Λ bending also follows from standard Weyl focusing, and so again, it cannot be a coordinate effect.
An Alcohol Test for Drifting Constants
Jansen, P.; Bagdonaite, J.; Ubachs, W.; Bethlem, H. L.; Kleiner, I.; Xu, L.-H.
2013-06-01
The Standard Model of physics is built on the fundamental constants of nature, however without providing an explanation for their values, nor requiring their constancy over space and time. Molecular spectroscopy can address this issue. Recently, we found that microwave transitions in methanol are extremely sensitive to a variation of the proton-to-electron mass ratio μ, due to a fortuitous interplay between classically forbidden internal rotation and rotation of the molecule as a whole. In this talk, we will explain the origin of this effect and how the sensitivity coefficients in methanol are calculated. In addition, we set a limit on a possible cosmological variation of μ by comparing transitions in methanol observed in the early Universe with those measured in the laboratory. Based on radio-astronomical observations of PKS1830-211, we deduce a constraint of Δμ/μ=(0.0± 1.0)× 10^{-7} at redshift z = 0.89, corresponding to a look-back time of 7 billion years. While this limit is more constraining and systematically more robust than previous ones, the methanol method opens a new search territory for probing μ-variation on cosmological timescales. P. Jansen, L.-H. Xu, I. Kleiner, W. Ubachs, and H.L. Bethlem Phys. Rev. Lett. {106}(100801) 2011. J. Bagdonaite, P. Jansen, C. Henkel, H.L. Bethlem, K.M. Menten, and W. Ubachs Science {339}(46) 2013.
Fundamental constants and high-resolution spectroscopy
Bonifacio, P.; Rahmani, H.; Whitmore, J. B.; Wendt, M.; Centurion, M.; Molaro, P.; Srianand, R.; Murphy, M. T.; Petitjean, P.; Agafonova, I. I.; D'Odorico, S.; Evans, T. M.; Levshakov, S. A.; Lopez, S.; Martins, C. J. A. P.; Reimers, D.; Vladilo, G.
2014-01-01
Absorption-line systems detected in high resolution quasar spectra can be used to compare the value of dimensionless fundamental constants such as the fine-structure constant, α, and the proton-to-electron mass ratio, μ = m_p/m_e, as measured in remote regions of the Universe to their value today on Earth. In recent years, some evidence has emerged of small temporal and also spatial variations in α on cosmological scales which may reach a fractional level of ≈ 10 ppm (parts per million). We are conducting a Large Programme of observations with the Very Large Telescope's Ultraviolet and Visual Echelle Spectrograph (UVES), and are obtaining high-resolution ({R ≈ 60 000}) and high signal-to-noise ratio (S/N ≈ 100) spectra calibrated specifically to study the variations of the fundamental constants. We here provide a general overview of the Large Programme and report on the first results for these two constants, discussed in detail in Molaro et al. (2013) and Rahmani et al. (2013). A stringent bound for Δα/α is obtained for the absorber at z_abs = 1.6919 towards HE 2217-2818. The absorption profile is complex with several very narrow features, and is modeled with 32 velocity components. The relative variation in α in this system is +1.3± 2.4_stat ± 1.0_sys ppm if Al II λ 1670 Å and three Fe II transitions are used, and +1.1 ± 2.6_stat ppm in a slightly different analysis with only Fe II transitions used. This is one of the tightest bounds on α-variation from an individual absorber and reveals no evidence for variation in α at the 3-ppm precision level (1σ confidence). The expectation at this sky position of the recently-reported dipolar variation of α is (3.2-5.4)±1.7 ppm depending on dipole model used and this constraint of Δα/α at face value is not supporting this expectation but not inconsistent with it at the 3σ level. For the proton-to-electron mass ratio the analysis of the H_2 absorption lines of the z_abs ≈ 2.4018 damped Lyα system
... to treat acne, bipolar disorder, and ADHD. Diet pills that contain amphetamines also can cause hair loss. Alopecia areata (pronounced: al-uh-PEE-shuh air-ee-AH-tuh) . This skin disease causes hair ...
Axiomatic approach to the cosmological constant
Beck, Christian
2009-09-01
A theory of the cosmological constant Λ is currently out of reach. Still, one can start from a set of axioms that describe the most desirable properties a cosmological constant should have. This can be seen in certain analogy to the Khinchin axioms in information theory, which fix the most desirable properties an information measure should have and that ultimately lead to the Shannon entropy as the fundamental information measure on which statistical mechanics is based. Here we formulate a set of axioms for the cosmological constant in close analogy to the Khinchin axioms, formally replacing the dependence of the information measure on probabilities of events by a dependence of the cosmological constant on the fundamental constants of nature. Evaluating this set of axioms one finally arrives at a formula for the cosmological constant given by Λ=1ħG(, where G is the gravitational constant, me the electron mass, and α the low-energy limit of the fine structure constant. This formula is in perfect agreement with current WMAP data. Our approach gives physical meaning to the Eddington-Dirac large-number hypothesis and suggests that the observed value of the cosmological constant is not at all unnatural.
A natural cosmological constant from chameleons
Energy Technology Data Exchange (ETDEWEB)
Nastase, Horatiu, E-mail: nastase@ift.unesp.br [Instituto de Física Teórica, UNESP-Universidade Estadual Paulista, R. Dr. Bento T. Ferraz 271, Bl. II, Sao Paulo 01140-070, SP (Brazil); Weltman, Amanda, E-mail: amanda.weltman@uct.ac.za [Astrophysics, Cosmology & Gravity Center, Department of Mathematics and Applied Mathematics, University of Cape Town, Private Bag, Rondebosch 7700 (South Africa)
2015-07-30
We present a simple model where the effective cosmological constant appears from chameleon scalar fields. For a Kachru–Kallosh–Linde–Trivedi (KKLT)-inspired form of the potential and a particular chameleon coupling to the local density, patches of approximately constant scalar field potential cluster around regions of matter with density above a certain value, generating the effect of a cosmological constant on large scales. This construction addresses both the cosmological constant problem (why Λ is so small, yet nonzero) and the coincidence problem (why Λ is comparable to the matter density now)
A natural cosmological constant from chameleons
Directory of Open Access Journals (Sweden)
Horatiu Nastase
2015-07-01
Full Text Available We present a simple model where the effective cosmological constant appears from chameleon scalar fields. For a Kachru–Kallosh–Linde–Trivedi (KKLT-inspired form of the potential and a particular chameleon coupling to the local density, patches of approximately constant scalar field potential cluster around regions of matter with density above a certain value, generating the effect of a cosmological constant on large scales. This construction addresses both the cosmological constant problem (why Λ is so small, yet nonzero and the coincidence problem (why Λ is comparable to the matter density now.
... hair if you have certain diseases, such as thyroid problems, diabetes, or lupus. If you take certain medicines or have chemotherapy for cancer, you may also lose your hair. Other causes are stress, a low protein diet, a family history, or poor nutrition. Treatment for hair loss depends ...
... birth defects and other medical conditions run in families, and how they can affect your health and your baby's health. There are ... Too Soon Global Map Premature birth report card Careers Archives ... Family health & safety Complications & Loss Pregnancy complications Preterm labor & ...
2008-01-01
Ecole de physique - Département de physique nucléaire et corpusculaire 24, Quai Ernest-Ansermet 1211 GENEVE 4 Tél: (022) 379 62 73 Fax: (022) 379 69 92 Monday 28 April 2008 PHYSICS COLLOQUIUM at 17.00 – Stückelberg Auditorium Gravity : an Emergent Perspective by Prof. Thanu Padmanabhan, Pune University Dean, Ganeshkhind, Pune, India I will motivate and describe a novel perspective in which gravity arises as an emergent phenomenon, somewhat like elasticity. This perspective throws light on several issues which are somewhat of a mystery in the conventional approach. Moreover it provides new insights on the dark energy problem. In fact, I will show that it is necessary to have such an alternative perspective in order to solve the cosmological constant problem.Information: http://theory.physics.unige.ch/~fiteo/seminars/COL/collist.html
Constant Width Planar Computation Characterizes ACC0
DEFF Research Database (Denmark)
Hansen, K.A.
2004-01-01
We obtain a characterization of ACC 0 in terms of a natural class of constant width circuits, namely in terms of constant width polynomial size planar circuits. This is shown via a characterization of the class of acyclic digraphs which can be embedded on a cylinder surface in such a way that all...
Stability constants for silicate adsorbed to ferrihydrite
DEFF Research Database (Denmark)
Hansen, Hans Christian Bruun; Wetche, T.P.; Raulund-Rasmussen, Karsten
1994-01-01
Intrinsic surface acidity constants (K(a1)intr, K(a2)intr) and surface complexation constant for adsorption of orthosilicate onto synthetic ferrihydrite (K(Si) for the complex = FeOSi(OH)3) have been determined from acid/base titrations in 0.001-0.1 m NaClO4 electrolytes and silicate adsorption e...
DETERMINATION OF STABILITY CONSTANTS OF MANGANESE (II ...
African Journals Online (AJOL)
DR. AMINU
Keywords: Amino acids, dissociation constant, potentiometry, stability constant. INTRODUCTION. Acids – base titration involves the gradual addition or removal of protons for example using the deprotic form of glycine. The plot has two distinct stages corresponding to the deprotonation of the two different groups on glycine.
Some zero-sum constants with weights
Indian Academy of Sciences (India)
Home; Journals; Proceedings – Mathematical Sciences; Volume 118; Issue 2. Some Zero-Sum Constants with Weights. S D Adhikari ... Motivated by some recent developments around the notion of Davenport constant with weights, we study them in some basic cases. We also define a new combinatorial invariant related to ...
Fullerene derivatives with increased dielectric constants
Jahani, Fatemeh; Torabi, Solmaz; Chiechi, Ryan C; Koster, L Jan Anton; Hummelen, Jan C
2014-01-01
The invention of new organic materials with high dielectric constants is of extreme importance for the development of organic-based devices such as organic solar cells. We report on a synthetic way to increase the dielectric constant of fullerene derivatives. It is demonstrated that introducing
Electromechanical systems generating constant frequency alternating current
Directory of Open Access Journals (Sweden)
Т.А. Мазур
2008-01-01
Full Text Available In the article we consider the usage of electromechanical drivers of constant speed rotation, which is based on many stepped electrodynamic reduction unit, in onboard main systems of electric supply of alternative current with constant frequency.
Shapley value for constant-sum games
Khmelnitskaya, Anna Borisovna
2003-01-01
It is proved that Young’s [4] axiomatization for the Shapley value by marginalism, efficiency, and symmetry is still valid for the Shapley value defined on the class of nonnegative constant-sum games with nonzero worth of grand coalition and on the entire class of constant-sum games as well.
Graviton fluctuations erase the cosmological constant
Wetterich, C.
2017-10-01
Graviton fluctuations induce strong non-perturbative infrared renormalization effects for the cosmological constant. The functional renormalization flow drives a positive cosmological constant towards zero, solving the cosmological constant problem without the need to tune parameters. We propose a simple computation of the graviton contribution to the flow of the effective potential for scalar fields. Within variable gravity, with effective Planck mass proportional to the scalar field, we find that the potential increases asymptotically at most quadratically with the scalar field. The solutions of the derived cosmological equations lead to an asymptotically vanishing cosmological ;constant; in the infinite future, providing for dynamical dark energy in the present cosmological epoch. Beyond a solution of the cosmological constant problem, our simplified computation also entails a sizeable positive graviton-induced anomalous dimension for the quartic Higgs coupling in the ultraviolet regime, substantiating the successful prediction of the Higgs boson mass within the asymptotic safety scenario for quantum gravity.
The Gravitational Instability of the Vacuum: Insight into the Cosmological Constant Problem
Energy Technology Data Exchange (ETDEWEB)
Alexander, S
2004-07-06
A mechanism for suppressing the cosmological constant is developed, based on an analogy with a superconducting phaseshift in which free fermions coupled perturbatively to a weak gravitational field are in an unstable false vacuum state. The coupling of the fermions to the gravitational field generates fermion condensates with zero momentum and a phase transition induces a nonperturbative transition to a true vacuum state by producing a positive energy gap {Delta} in the vacuum energy, identified with {radical}{Lambda}, where {Lambda} is the cosmological constant. In the strong coupling limit a large cosmological constant induces a period of inflation in the early universe, followed by a weak coupling limit in which {radical}{Lambda} vanishes exponentially fast as the universe expands due to the dependence of the energy gap on the density of Fermi surface fermions, D({epsilon}), predicting a small cosmological constant in the present universe.
Kelly, F. P.
1991-01-01
This paper describes work on the stochastic modelling of loss networks. Such systems have long been of interest to telephone engineers and are becoming increasingly important as models of computer and information systems. Throughout the century problems from this field have provided an impetus to the development of probability theory, pure and applied. This paper provides an introduction to the area and a review of recent work.
A nuclear data approach for the Hubble constant measurements
Energy Technology Data Exchange (ETDEWEB)
Pritychenko, B. [Brookhaven National Laboratory (BNL), Upton, NY (United States)
2015-06-09
An extraordinary number of Hubble constant measurements challenges physicists with selection of the best numerical value. The standard U.S. Nuclear Data Program (USNDP) codes and procedures have been applied to resolve this issue. The nuclear data approach has produced the most probable or recommended Hubble constant value of 67.00(770) (km/sec)/Mpc. This recommended value is based on the last 25 years of experimental research and includes contributions from different types of measurements. The present result implies (14.6±1.7) x 10^{9} years as a rough estimate for the age of the Universe. The complete list of recommended results is given and possible implications are discussed.
Constant mortality and fertility over age in Hydra
DEFF Research Database (Denmark)
Schaible, R.; Scheuerlein, A.; Danko, M. J.
2015-01-01
Senescence, the increase in mortality and decline in fertility with age after maturity, was thought to be inevitable for all multicellular species capable of repeated breeding. Recent theoretical advances and compilations of data suggest that mortality and fertility trajectories can go up or down...... that 2,256 Hydra from two closely related species in two laboratories in 12 cohorts, with cohort age ranging from 0 to more than 41 y, have extremely low, constant rates of mortality. Fertility rates for Hydra did not systematically decline with advancing age. This falsifies the universality...... expectancy of Hydra in the wild. A high proportion of stem cells, constant and rapid cell turnover, few cell types, a simple body plan, and the fact that the germ line is not segregated from the soma are characteristics of Hydra that may make nonsenescence feasible. Nonsenescence may be optimal because...
Uniform Hashing in Constant Time and Optimal Space
DEFF Research Database (Denmark)
Pagh, Anna Östlin; Pagh, Rasmus
2008-01-01
Many algorithms and data structures employing hashing have been analyzed under the uniform hashing assumption, i.e., the assumption that hash functions behave like truly random functions. Starting with the discovery of universal hash functions, many researchers have studied to what extent...... this theoretical ideal can be realized by hash functions that do not take up too much space and can be evaluated quickly. In this paper we present an almost ideal solution to this problem: a hash function $h: U\\rightarrow V$ that, on any set of $n$ inputs, behaves like a truly random function with high probability......, can be evaluated in constant time on a RAM and can be stored in $(1+\\epsilon)n\\log |V| + O(n+\\log\\log |U|)$ bits. Here $\\epsilon$ can be chosen to be any positive constant, so this essentially matches the entropy lower bound. For many hashing schemes this is the first hash function that makes...
Cosmological perturbations of axion with a dynamical decay constant
Energy Technology Data Exchange (ETDEWEB)
Kobayashi, Takeshi [SISSA,Via Bonomea 265, 34136 Trieste (Italy); INFN, Sezione di Trieste,Via Bonomea 265, 34136 Trieste (Italy); Takahashi, Fuminobu [Department of Physics, Tohoku University,Sendai, Miyagi 980-8578 (Japan); Kavli IPMU (WPI), UTIAS, The University of Tokyo,Kashiwa, Chiba 277-8583 (Japan)
2016-08-25
A QCD axion with a time-dependent decay constant has been known to be able to accommodate high-scale inflation without producing topological defects or too large isocurvature perturbations on CMB scales. We point out that a dynamical decay constant also has the effect of enhancing the small-scale axion isocurvature perturbations. The enhanced axion perturbations can even exceed the periodicity of the axion potential, and thus lead to the formation of axionic domain walls. Unlike the well-studied axionic walls, the walls produced from the enhanced perturbations are not bounded by cosmic strings, and thus would overclose the universe independently of the number of degenerate vacua along the axion potential.
A nuclear data approach for the Hubble constant measurements
Directory of Open Access Journals (Sweden)
Pritychenko Boris
2017-01-01
Full Text Available An extraordinary number of Hubble constant measurements challenges physicists with selection of the best numerical value. The standard U.S. Nuclear Data Program (USNDP codes and procedures have been applied to resolve this issue. The nuclear data approach has produced the most probable or recommended Hubble constant value of 67.2(69 (km/sec/Mpc. This recommended value is based on the last 20 years of experimental research and includes contributions from different types of measurements. The present result implies (14.55 ± 1.51 × 109 years as a rough estimate for the age of the Universe. The complete list of recommended results is given and possible implications are discussed.
Constants and Pseudo-Constants of Coupled Beam Motion in the PEP-II Rings
Energy Technology Data Exchange (ETDEWEB)
Decker, F.J.; Colocho, W.S.; Wang, M.H.; Yan, Y.T.; Yocky, G.; /SLAC
2011-11-01
Constants of beam motion help as cross checks to analyze beam diagnostics and the modeling procedure. Pseudo-constants, like the betatron mismatch parameter or the coupling parameter det C, are constant till certain elements in the beam line change them. This can be used to visually find the non-desired changes, pinpointing errors compared with the model.
The university professor: integration between the personal and professional dimension
Directory of Open Access Journals (Sweden)
José Javier BERMÚDEZ-APONTE
2017-12-01
Full Text Available In the first part of this article, the authors explain how the teaching role is affected by certain social and cultural changes, like the knowledge society emergence, the universities orientation towards marketing, the constant demand and pressure exerted on teachers to publish, the loss of the ethical sense in the academic activity and the disparity of tasks that are being assigned to the university professors. In view of the above, a comprehensive model, compound by two concepts –personal and professional– of a university professor is proposed; in fact, this model incorporates and summarises different contributions regarding this theme. Finally, this article aims to defend the need to understand the teaching role as a vocation, in the broadest sense of the word, a vocation carries the inclination to pursue an aim: the education of those students that teachers have in charge.
Indian Academy of Sciences (India)
W de Sitter wrote a paper in which he solved Einstein's equations with the A-term, and obtained a model in which the universe expands with a scale factor that increases exponentially with time. The Hubble constant for this univers~ is given by. H = [(113) Ac2]l/2. Thus this model is apparently closer to reality than Einstein's.
Graviton fluctuations erase the cosmological constant
Directory of Open Access Journals (Sweden)
C. Wetterich
2017-10-01
Full Text Available Graviton fluctuations induce strong non-perturbative infrared renormalization effects for the cosmological constant. The functional renormalization flow drives a positive cosmological constant towards zero, solving the cosmological constant problem without the need to tune parameters. We propose a simple computation of the graviton contribution to the flow of the effective potential for scalar fields. Within variable gravity, with effective Planck mass proportional to the scalar field, we find that the potential increases asymptotically at most quadratically with the scalar field. The solutions of the derived cosmological equations lead to an asymptotically vanishing cosmological “constant” in the infinite future, providing for dynamical dark energy in the present cosmological epoch. Beyond a solution of the cosmological constant problem, our simplified computation also entails a sizeable positive graviton-induced anomalous dimension for the quartic Higgs coupling in the ultraviolet regime, substantiating the successful prediction of the Higgs boson mass within the asymptotic safety scenario for quantum gravity.
The time constant of the somatogravic illusion
Correia Grácio, B.J.; Winkel, K.N. de; Groen, E.L.; Wentink, M.; Bos, J.E.
2013-01-01
Met desdemona hebben we gevonden dat de tijd constante van de somatografische illusie rond twee seconden is. Dit resultaat verschilt van wat was gevonden in ander onderzoek dat gebruikt maakt van een gewone centrifuge
Nonlocal modified Einstein's field equation and geometric origin of a small cosmological constant
El-Nabulsi, Rami Ahmad
2018-01-01
We show that the description of the spacetime in terms of backward-forward extension of its corresponding metric leads to the geometric origin of a small cosmological constant. The nonlocal cosmological constant appears in the Einstein's field equation and its mathematical expression depends on the nonlocal metric, Ricci scalar and the infinitesimal nonlocal parameter introduced in the theory. The modified theory has interesting consequences in FRW cosmology, mainly a nonsingular universe, the occurrence of a late-time accelerated expansion of the universe and an early universe dominated by a negative energy density and a positive pressure. Our model can explain the acceleration of the universe without a fine-tuned cosmological constant Λ.
Building evolutionary architectures support constant change
Ford, Neal; Kua, Patrick
2017-01-01
The software development ecosystem is constantly changing, providing a constant stream of new tools, frameworks, techniques, and paradigms. Over the past few years, incremental developments in core engineering practices for software development have created the foundations for rethinking how architecture changes over time, along with ways to protect important architectural characteristics as it evolves. This practical guide ties those parts together with a new way to think about architecture and time.
Trialogue on the number of fundamental constants
Duff, Michael J; Veneziano, Gabriele
2002-01-01
This paper consists of three separate articles on the number of fundamental dimensionful constants in physics. We started our debate in summer 1992 on the terrace of the famous CERN cafeteria. In the summer of 2001 we returned to the subject to find that our views still diverged and decided to explain our current positions. LBO develops the traditional approach with three constants, GV argues in favor of just two, while MJD advocates zero.
Implications of a positive cosmological constant for general relativity
Ashtekar, Abhay
2017-10-01
Most of the literature on general relativity over the last century assumes that the cosmological constant Λ is zero. However, by now independent observations have led to a consensus that the dynamics of the universe is best described by Einstein’s equations with a small but positive Λ . Interestingly, this requires a drastic revision of conceptual frameworks commonly used in general relativity, no matter how small Λ is. We first explain why, and then summarize the current status of generalizations of these frameworks to include a positive Λ , focusing on gravitational waves.
Implications of a positive cosmological constant for general relativity.
Ashtekar, Abhay
2017-10-01
Most of the literature on general relativity over the last century assumes that the cosmological constant [Formula: see text] is zero. However, by now independent observations have led to a consensus that the dynamics of the universe is best described by Einstein's equations with a small but positive [Formula: see text]. Interestingly, this requires a drastic revision of conceptual frameworks commonly used in general relativity, no matter how small [Formula: see text] is. We first explain why, and then summarize the current status of generalizations of these frameworks to include a positive [Formula: see text], focusing on gravitational waves.
Uraemia progression in chronic kidney disease stages 3-5 is not constant
DEFF Research Database (Denmark)
Heaf, James Goya; Mortensen, Leif Spange
2011-01-01
Chronic kidney disease (CKD) is a progressive disease leading to loss of glomerular filtration rate (ΔGFR, measured in ml/min/1.73 m(2)/year). ΔGFR is usually assumed to be constant, but the hyperfiltration theory suggests that it accelerates in severe uraemia. A retrospective analysis of estimated...... GFR (eGFR) calculated from the Modification of Diet in Renal Disease equation was performed to evaluate whether ΔGFR is constant or accelerating....
Prescription weight loss drugs; Diabetes - weight loss drugs; Obesity - weight loss drugs; Overweight - weight loss drugs ... are not approved by the FDA to treat weight-loss. So you should not take them if you do not have diabetes.
Exacerbating the Cosmological Constant Problem with Interacting Dark Energy Models.
Marsh, M C David
2017-01-06
Future cosmological surveys will probe the expansion history of the Universe and constrain phenomenological models of dark energy. Such models do not address the fine-tuning problem of the vacuum energy, i.e., the cosmological constant problem (CCP), but can make it spectacularly worse. We show that this is the case for "interacting dark energy" models in which the masses of the dark matter states depend on the dark energy sector. If realized in nature, these models have far-reaching implications for proposed solutions to the CCP that require the number of vacua to exceed the fine-tuning of the vacuum energy density. We show that current estimates of the number of flux vacua in string theory, N_{vac}∼O(10^{272 000}), are far too small to realize certain simple models of interacting dark energy and solve the cosmological constant problem anthropically. These models admit distinctive observational signatures that can be targeted by future gamma-ray observatories, hence making it possible to observationally rule out the anthropic solution to the cosmological constant problem in theories with a finite number of vacua.
Vanishing cosmological constant in elementary particles theory
Energy Technology Data Exchange (ETDEWEB)
Pisano, F. [Instituto de Fisica Teorica (IFT), Sao Paulo, SP (Brazil); Tonasse, M.D. [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Fisica
1997-01-01
The quest of a vanishing cosmological constant is considered in the simplest anomaly-free chiral gauge extension of the electroweak standard model where the new physics is limited to a well defined additional flavordynamics above the Fermi scale, namely up to a few TeVs by matching the gauge coupling constants at the electroweak scale, and with an extended Higgs structure. In contrast to the electroweak standard model, it is shown how the extended scalar sector of the theory allows a vanishing or a very small cosmological constant. the details of the cancellation mechanism are presented. At accessible energies the theory is indistinguishable from the standard model of elementary particles and it is in agreement with all existing data. (author). 32 refs. 32 refs.
BRS structure of simple model of cosmological constant and cosmology
Mori, Taisaku; Nitta, Daisuke; Nojiri, Shin'ichi
2017-07-01
In Mod. Phys. Lett. A 31, 1650213 (2016, 10.1142/S0217732316502138), Nojiri proposed a simple model in order to solve one of the problems related to the cosmological constant. The model is induced from a topological field theory, and the model has an infinite number of BRS symmetries. The BRS symmetries are, in general, spontaneously broken, however. We investigate the BRS symmetry in detail and show that there is one and only one BRS symmetry which is not broken, and the unitarity can be guaranteed. In the model, the quantum problem of the vacuum energy, which may be identified with the cosmological constant, reduces to the classical problem of the initial condition. We investigate the cosmology given by the model and specify the region of the initial conditions, which could be consistent with the evolution of the Universe. We also show that there is a stable solution describing the de Sitter space-time, which may explain the accelerating expansion in the current Universe.
Motohashi, Hayato; Starobinsky, Alexei A.
2017-08-01
The previously introduced class of two-parametric phenomenological inflationary models in general relativity in which the slow-roll assumption is replaced by the more general, constant-roll condition is generalized to the case of f( R) gravity. A simple constant-roll condition is defined in the original Jordan frame, and exact expressions for a scalaron potential in the Einstein frame, for a function f( R) (in the parametric form) and for inflationary dynamics are obtained. The region of the model parameters permitted by the latest observational constraints on the scalar spectral index and the tensor-to-scalar ratio of primordial metric perturbations generated during inflation is determined.
Cosmological constant, supersymmetry, nonassociativity, and big numbers
Energy Technology Data Exchange (ETDEWEB)
Dzhunushaliev, Vladimir [KazNU, Department of Theoretical and Nuclear Physics, Almaty (Kazakhstan); IETP, Al-Farabi KazNU, Almaty (Kazakhstan)
2015-02-01
The nonassociative generalization of supersymmetry is considered. It is shown that the associator of four supersymmetry generators has the coefficient ∝ ℎ/l{sub 0}{sup 2} where l0 is some characteristic length. Two cases are considered: (a) l{sub 0}{sup -2} coincides with the cosmological constant; (b) l{sub 0} is the classical radius of the electron. It is also shown that the scaled constant is of the order of 10{sup -120} for the first case and 10{sup -30} for the second case. The possible manifestation and smallness of nonassociativity is discussed. (orig.)
Flexible alternatives to constant frequency systems
Stewart-Wilson, John
The use of hybrid systems in which variable frequency is used as generated, with a proportion being converted to constant frequency by electronic conversion, is examined as a flexible alternative to constant frequency systems. Here, some practical solutions to the technical issues raised by adopting the more flexible approach to electrical system generation are presented. In particular, attention is given to the frequency ranges used, impact on aircraft equipment, motor-driven equipment, transformer rectifier units, lighting, and avionics. The discussion also covers fan-assisted galley ovens, system architecture, special airworthiness requirements, and power quality.
Reconstruction of constant slow-roll inflation
Gao, Qing
2017-09-01
Using the relations between the slow-roll parameters and the power spectra for the single field slow-roll inflation, we derive the scalar spectral tilt n s and the tensor to scalar ratio r for the constant slow-roll inflation, and obtain the constraint on the slow-roll parameter η from the Planck 2015 results. The inflationary potential for the constant slow-roll inflation is then reconstructed in the framework of both general relativity and the scalar-tensor theory of gravity, and compared with the recently reconstructed E model potential. In the strong coupling limit, we show that the η attractor is reached.
Constant mortality and fertility over age in Hydra.
Schaible, Ralf; Scheuerlein, Alexander; Dańko, Maciej J; Gampe, Jutta; Martínez, Daniel E; Vaupel, James W
2015-12-22
Senescence, the increase in mortality and decline in fertility with age after maturity, was thought to be inevitable for all multicellular species capable of repeated breeding. Recent theoretical advances and compilations of data suggest that mortality and fertility trajectories can go up or down, or remain constant with age, but the data are scanty and problematic. Here, we present compelling evidence for constant age-specific death and reproduction rates in Hydra, a basal metazoan, in a set of experiments comprising more than 3.9 million days of observations of individual Hydra. Our data show that 2,256 Hydra from two closely related species in two laboratories in 12 cohorts, with cohort age ranging from 0 to more than 41 y, have extremely low, constant rates of mortality. Fertility rates for Hydra did not systematically decline with advancing age. This falsifies the universality of the theories of the evolution of aging that posit that all species deteriorate with age after maturity. The nonsenescent life history of Hydra implies levels of maintenance and repair that are sufficient to prevent the accumulation of damage for at least decades after maturity, far longer than the short life expectancy of Hydra in the wild. A high proportion of stem cells, constant and rapid cell turnover, few cell types, a simple body plan, and the fact that the germ line is not segregated from the soma are characteristics of Hydra that may make nonsenescence feasible. Nonsenescence may be optimal because lifetime reproduction may be enhanced more by extending adult life spans than by increasing daily fertility.
Quantifying the flow efficiency in constant-current capacitive deionization.
Hawks, Steven A; Knipe, Jennifer M; Campbell, Patrick G; Loeb, Colin K; Hubert, McKenzie A; Santiago, Juan G; Stadermann, Michael
2018-02-01
Here we detail a previously unappreciated loss mechanism inherent to capacitive deionization (CDI) cycling operation that has a substantial role determining performance. This mechanism reflects the fact that desalinated water inside a cell is partially lost to re-salination if desorption is carried out immediately after adsorption. We describe such effects by a parameter called the flow efficiency, and show that this efficiency is distinct from and yet multiplicative with other highly-studied adsorption efficiencies. Flow losses can be minimized by flowing more feed solution through the cell during desalination; however, this also results in less effluent concentration reduction. While the rationale outlined here is applicable to all CDI cell architectures that rely on cycling, we validate our model with a flow-through electrode CDI device operated in constant-current mode. We find excellent agreement between flow efficiency model predictions and experimental results, thus giving researchers simple equations by which they can estimate this distinct loss process for their operation. Copyright © 2017 Elsevier Ltd. All rights reserved.
Union-Find with Constant Time Deletions
DEFF Research Database (Denmark)
Alstrup, Stephen; Thorup, Mikkel; Gørtz, Inge Li
2014-01-01
modification of the classical union-find data structure that supports delete, as well as makeset and union operations, in constant worst-case time, while still supporting find operations in O(log n) worst-case time and O(α_M/N_(n)) amortized time. Our analysis supplies, in particular, a very concise potential...
Timelike Constant Mean Curvature Surfaces with Singularities
DEFF Research Database (Denmark)
Brander, David; Svensson, Martin
2014-01-01
We use integrable systems techniques to study the singularities of timelike non-minimal constant mean curvature (CMC) surfaces in the Lorentz–Minkowski 3-space. The singularities arise at the boundary of the Birkhoff big cell of the loop group involved. We examine the behavior of the surfaces...
Some zero-sum constants with weights
Indian Academy of Sciences (India)
imsc.res.in. MS received 28 February 2007. Abstract. For an abelian group G, the Davenport constant D(G) is defined to be the smallest natural number k such that any sequence of k elements in G has a non- empty subsequence whose sum is ...
Benjamin Constant. Ontdekker van de moderne vrijheid
de Hert, Paul; Kinneging, A.; Colette, M.
2015-01-01
In 1806 analyseerde de Zwitsers-Franse politicus, filosoof en essayist Benjamin Constant (1767-1830) de moderne samenleving in zijn bekende boek Principes de politique. Uit dit klassiek geworden werk spreekt Constant’s ambivalentie en gevoel van nuance en subtiliteit. De “moderne” individuele
Experimental Determination of the Avogadro Constant
Indian Academy of Sciences (India)
obtained from a frame-by-frame analysis of the video over a suffi- ciently long period of time. The diffusion coefficient D is given by σ 2/(2∆t). Once again using Stokes–Einstein relation (equation 6) we can obtain the Boltzmann constant and hence the Avogadro number. Counting α Particles. Rutherford in 1903 demonstrated ...
Redundant internal coordinates, compliance constants and non ...
Indian Academy of Sciences (India)
If chosen properly, the internal coordinates will have minimum mixing in the normal mode representation. This can in principle lead to an automation ... It was shown in the literature that the relaxed force constants could be used as a measure of bond order in all atom-atom distance coordinates. Some of the bonded and ...
Redundant internal coordinates, compliance constants and non ...
Indian Academy of Sciences (India)
Redundant internal coordinates, compliance constants and non-bonded interactions – some new insights. MOUMITA MAJUMDER and SADASIVAM MANOGARAN. ∗. Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, India e-mail: sm@iitk.ac.in. MS received 21 February 2012; revised 8 July ...
Pion decay constants in dense skyrmion matter
Directory of Open Access Journals (Sweden)
Lee H.-J.
2010-10-01
Full Text Available According to the QCD, the hadronic matter can have various phases with matter density and temperature. In general, when there is phase transition in a matter, it is known that a symmetry in the matter changes. In case of the hadronic matter, the chiral symmetry in the matter is expected to be restored when the matter density (or temperature increases. The actual order parameter with respect to the chiral symmetry in the hadronic matter is known as the quark condensate from the QCD, but the pion decay constant, corresponding to the radius of the chiral circle, plays the role of the order parameter in an eﬀective ﬁeld theoretical approach to the QCD. In this paper, by using the skyrmion model which is an eﬀective theory to the QCD, we construct the skyrmion matter as a model of the hadronic matter (nuclear matter and calculate the pion decay constant in the matter. Because of presence of the matter, the pion decay constant is split into the two components, the temporal component and the spatial component. We discuss the phase transition in the skyrmion matter and behavior of the two components of the decay constant for massless pion with density of the skyrmion matter.
Teaching Nanochemistry: Madelung Constants of Nanocrystals
Baker, Mark D.; Baker, A. David
2010-01-01
The Madelung constants for binary ionic nanoparticles are determined. The computational method described here sums the Coulombic interactions of each ion in the particle without the use of partial charges commonly used for bulk materials. The results show size-dependent lattice energies. This is a useful concept in teaching how properties such as…
Optical Constants of Cometary Ice Tholins
Khare, B. N.; Cruikshank, D.; Arakawa, E. T.; McDonald, G. D.
1997-07-01
We have previously reported the optical constants from 0.06 to 40 mu m of ice tholin I, produced by plasma irradiation of 1:6 ethane:water frost at 77K (Khare et al. 1993, Icarus 103, 290). Such ices containing water and small amounts of simple hydrocarbons either in the form of clathrates or intimate physical mixtures are thought to be common outer solar system condensates that were incorporated into comets and other bodies. For the imaginary part of the refractive index (k)index n is not affected by these changes since the k values are small. Here we present our revised optical constants for ice tholin I, and compare with optical constants of ice tholin II, produced by plasma irradiation of ices made from a 80:16:3.2:0.8 water:methanol:carbon dioxide:ethane gas mixture (McDonald et al. 1996, Icarus 122, 107), a first order approximation to known and inferred cometary compositions. These additional data on the optical constants of ice tholin II will provide another choice for comparison with spectra of comets and other icy solar system bodies.
Constant force extensional rheometry of polymer solutions
DEFF Research Database (Denmark)
Szabo, Peter; McKinley, Gareth H.; Clasen, Christian
2012-01-01
We revisit the rapid stretching of a liquid filament under the action of a constant imposed tensile force, a problem which was first considered by Matta and Tytus [J. Non-Newton. Fluid Mech. 35 (1990) 215–229]. A liquid bridge formed from a viscous Newtonian fluid or from a dilute polymer solution...
dielectric constants of irradiated and carbonated polymers
African Journals Online (AJOL)
user
1985-09-01
Sep 1, 1985 ... irradiated and carbonated polymers as a function of carbon concentration are investigated. Both low and high density polymers are used. Results predict a quadratic increase in the dielectric constant of specimen as the percentage concentration of carbon is increased. This may be due to the formation of ...
on the correctness of load loss factor correctness of load loss factor ...
African Journals Online (AJOL)
eobe
Author Tel: +44 -753-526-7242. TECHNICAL NOTE: TECHNICAL NOTE: ON THE CORRECTNESS OF LOAD LOSS FACTOR. CORRECTNESS OF LOAD LOSS FACTOR. CORRECTNESS OF LOAD LOSS FACTOR. A. O. Ekwue*. JACOBS ENGINEERING INC/BRUNEL UNIVERSITY LONDON,UNITED KINGDOM.
Loss of metabolites from monkey striatum during PET with FDOPA
DEFF Research Database (Denmark)
Cumming, P; Munk, O L; Doudet, D
2001-01-01
constants using data recorded during 240 min of FDOPA circulation in normal monkeys and in monkeys with unilateral 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) lesions. Use of the extended models increased the magnitudes of K(D)(i) and k(D)(3) in striatum; in the case of k(D)(3), variance...... of the estimate was substantially improved upon correction for metabolite loss. The rate constants for metabolite loss were higher in MPTP-lesioned monkey striatum than in normal striatum. The high correlation between individual estimates of k(Lin)(cl) and k(DA)(9) suggests that both rate constants reveal loss...
Energy Technology Data Exchange (ETDEWEB)
Ramos, Manoel M.O.; Peixoto, J. Guilherme P., E-mail: mmoramos@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Pereira, Marco A.G.S., E-mail: guedes@iee.usp.b [Universidade de Sao Paulo (IEE/USP), SP (Brazil). Inst. de Eletrotecnica e Energia; Lopes, Ricardo T., E-mail: ricardo@lin.ufrj.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil)
2009-07-01
This work evaluates the utilization of the non invasive voltage meter PTW Diavolt Universal in industrial X ray equipment of constant potential. With the performed measurements, the conclusion is that conclusion is possible, once his use limits are identified
Bone loss, contraception and lactation.
Mehta, S
1993-04-01
Loss of bone mass with age, is a universal phenomenon and is more pronounced in women than in men. The condition where the bone loss has proceeded to the extent that fractures occur is termed osteoporosis. As the number of elderly persons in the population increases, its magnitude is likely to increase, both in the developing and the developed countries. Bone mass increases rapidly in childhood and the adolescent years, reaching a peak in the third decade of life, and begins to decline soon thereafter. Several factors are thought to influence bone loss: these include race, diet, smoking, and physical exercise. Although the rate of bone loss accelerates in the immediate postmenopausal period, the process actually begins in the premenopausal years. By the time osteoporosis is clinically apparent and manifested by fracture, it probably cannot be reversed. The peak adult bone mass achieved, and the subsequent rate of bone loss are the major factors that determine a woman's susceptibility to postmenopausal osteoporosis. A primary cause of bone loss after menopause is the associated decline in ovarian function. Scanty information is available on the factors that affect bone mineral density or initiate bone loss before menopause, although both estrogens and progestins have been shown to prevent bone loss in postmenopausal women. Available data on the relationship between steroid hormone contraceptive use and bone mass/density is limited to combined oral contraceptives and one report related to the use of depot medroxyprogesterone acetate.(ABSTRACT TRUNCATED AT 250 WORDS)
Construction of Lines of Constant Density and Constant Refractive Index for Ternary Liquid Mixtures.
Tasic, Aleksandar Z.; Djordjevic, Bojan D.
1983-01-01
Demonstrates construction of density constant and refractive index constant lines in triangular coordinate system on basis of systematic experimental determinations of density and refractive index for both homogeneous (single-phase) ternary liquid mixtures (of known composition) and the corresponding binary compositions. Background information,…
Profiles of equilibrium constants for self-association of aromatic molecules.
Beshnova, Daria A; Lantushenko, Anastasia O; Davies, David B; Evstigneev, Maxim P
2009-04-28
Analysis of the noncovalent, noncooperative self-association of identical aromatic molecules assumes that the equilibrium self-association constants are either independent of the number of molecules (the EK-model) or change progressively with increasing aggregation (the AK-model). The dependence of the self-association constant on the number of molecules in the aggregate (i.e., the profile of the equilibrium constant) was empirically derived in the AK-model but, in order to provide some physical understanding of the profile, it is proposed that the sources for attenuation of the equilibrium constant are the loss of translational and rotational degrees of freedom, the ordering of molecules in the aggregates and the electrostatic contribution (for charged units). Expressions are derived for the profiles of the equilibrium constants for both neutral and charged molecules. Although the EK-model has been widely used in the analysis of experimental data, it is shown in this work that the derived equilibrium constant, K(EK), depends on the concentration range used and hence, on the experimental method employed. The relationship has also been demonstrated between the equilibrium constant K(EK) and the real dimerization constant, K(D), which shows that the value of K(EK) is always lower than K(D).
DEFF Research Database (Denmark)
Pawlowski, F; Jorgensen, P; Olsen, Jeppe
2002-01-01
A detailed study is carried out of the accuracy of molecular equilibrium geometries obtained from least-squares fits involving experimental rotational constants B(0) and sums of ab initio vibration-rotation interaction constants alpha(r)(B). The vibration-rotation interaction constants have been...... calculated for 18 single-configuration dominated molecules containing hydrogen and first-row atoms at various standard levels of ab initio theory. Comparisons with the experimental data and tests for the internal consistency of the calculations show that the equilibrium structures generated using Hartree......-Fock vibration-rotation interaction constants have an accuracy similar to that obtained by a direct minimization of the CCSD(T) energy. The most accurate vibration-rotation interaction constants are those calculated at the CCSD(T)/cc-pVQZ level. The equilibrium bond distances determined from these interaction...
Moura, Clarissa de Almeida; Lima, Jéssica Polyana da Silva; Silveira, Vanessa Augusta Magalhães; Miguel, Mário André Leocadio; Luchiari, Ana Carolina
2017-05-01
The ability to learn about the signs of variability in space and time is known as time place learning (TPL). To adjust their circadian rhythms, animals use stimuli that change regularly, such as the light-dark cycle, temperature, food availability or even social stimuli. Because light-dark cycle is the most important environmental temporal cue, we asked how a diurnal animal would perform TPL if this cue was removed. Zebrafish has been extensively studied in the chronobiology area due to it diurnal chronotype, thus, we studied the effects of constant light and constant dark on the time-place learning and activity profile in zebrafish. Our data show that while under constant light and dark condition zebrafish was not able of TPL, after 30days under the constant conditions, constant light led to higher activity level and less significant (robust) 24h rhythm. Copyright © 2017 Elsevier B.V. All rights reserved.
Recurrent pregnancy loss: current perspectives
Directory of Open Access Journals (Sweden)
El Hachem H
2017-05-01
Full Text Available Hady El Hachem,1,2 Vincent Crepaux,3 Pascale May-Panloup,4 Philippe Descamps,3 Guillaume Legendre,3 Pierre-Emmanuel Bouet3 1Department of Reproductive Medicine, Ovo Clinic, Montréal, QC, Canada; 2Department of Obstetrics and Gynecology, University of Montreal, Montréal, QC, Canada; 3Department of Obstetrics and Gynecology, Angers University Hopsital, Angers, France; 4Department of Reproductive Biology, Angers University Hospital, Angers, France Abstract: Recurrent pregnancy loss is an important reproductive health issue, affecting 2%–5% of couples. Common established causes include uterine anomalies, antiphospholipid syndrome, hormonal and metabolic disorders, and cytogenetic abnormalities. Other etiologies have been proposed but are still considered controversial, such as chronic endometritis, inherited thrombophilias, luteal phase deficiency, and high sperm DNA fragmentation levels. Over the years, evidence-based treatments such as surgical correction of uterine anomalies or aspirin and heparin for antiphospholipid syndrome have improved the outcomes for couples with recurrent pregnancy loss. However, almost half of the cases remain unexplained and are empirically treated using progesterone supplementation, anticoagulation, and/or immunomodulatory treatments. Regardless of the cause, the long-term prognosis of couples with recurrent pregnancy loss is good, and most eventually achieve a healthy live birth. However, multiple pregnancy losses can have a significant psychological toll on affected couples, and many efforts are being made to improve treatments and decrease the time needed to achieve a successful pregnancy. This article reviews the established and controversial etiologies, and the recommended therapeutic strategies, with a special focus on unexplained recurrent pregnancy losses and the empiric treatments used nowadays. It also discusses the current role of preimplantation genetic testing in the management of recurrent pregnancy
Directory of Open Access Journals (Sweden)
Luciano Melo Coutinho
2014-01-01
Full Text Available Erosion is considered the main cause of depletion of agricultural land, which generates approximate annual losses of billions of dollars in Brazil. Water erosion is the most common, caused by effective precipitation basin, since its potential is the main agent of reshaping the land. Universal Equation Soil Loss (USLE show great applicability to estimate erosion in watersheds from their physical and geographical elements (PS = R*K*L*S*C*P. The intensity of erosion can be influenced by the profile of the slope, measured by the length (L and grade of slope (S. The topographic factor (LS of the USLE is the most difficult to obtain for large and/or diverse relief areas. We calculated the spatial map of the LS factor Silver watershed (Castelo-ES from the processing of cartographic data in environment Geographic Information Systems (GIS. The relief of the study area was represented by interpolation from contour lines supported mapped hydrography, give the digital elevation model hydrologically consistent (MDEHC and declivity map. For generation of the LS factor was used to equation developed by Bertoni and Lombardi Neto (2005, suitable for slopes of different length and declivity. The Silver watershed has diversified relief, marked by flat and steep declivity areas, which indicates erosive vulnerability. The main values of LS were identified minimum (0, medium (8.2 and maximum (80.5. = A erosão é apontada como a principal causa do depauperamento de terras agrícolas, o que gera prejuízos anuais aproximados da ordem de bilhões de dólares no Brasil. A erosão hídrica é a mais comum, ocasionada pela precipitação efetiva em bacias, que devido ao seu potencial erosivo é o principal agente de remodelagem do terreno. A Equação Universal de Perdas de Solos (EUPS mostra-se de grande aplicabilidade para estimar a erosão de bacias hidrográficas a partir de seus elementos físicos e geográficos (PS = R*K*L*S*C*P. A intensidade da erosão pode sofrer
Multiphoton amplitude in a constant background field
Ahmad, Aftab; Ahmadiniaz, Naser; Corradini, Olindo; Kim, Sang Pyo; Schubert, Christian
2018-01-01
In this contribution, we present our recent compact master formulas for the multiphoton amplitudes of a scalar propagator in a constant background field using the worldline fomulation of quantum field theory. The constant field has been included nonperturbatively, which is crucial for strong external fields. A possible application is the scattering of photons by electrons in a strong magnetic field, a process that has been a subject of great interest since the discovery of astrophysical objects like radio pulsars, which provide evidence that magnetic fields of the order of 1012G are present in nature. The presence of a strong external field leads to a strong deviation from the classical scattering amplitudes. We explicitly work out the Compton scattering amplitude in a magnetic field, which is a process of potential relevance for astrophysics. Our final result is compact and suitable for numerical integration.
Energy Technology Data Exchange (ETDEWEB)
Motohashi, Hayato [Universidad de Valencia-CSIC, Instituto de Fisica Corpuscular (IFIC), Valencia (Spain); Starobinsky, Alexei A. [L.D. Landau Institute for Theoretical Physics, RAS, Moscow (Russian Federation); National Research University Higher School of Economics, Moscow (Russian Federation)
2017-08-15
The previously introduced class of two-parametric phenomenological inflationary models in general relativity in which the slow-roll assumption is replaced by the more general, constant-roll condition is generalized to the case of f(R) gravity. A simple constant-roll condition is defined in the original Jordan frame, and exact expressions for a scalaron potential in the Einstein frame, for a function f(R) (in the parametric form) and for inflationary dynamics are obtained. The region of the model parameters permitted by the latest observational constraints on the scalar spectral index and the tensor-to-scalar ratio of primordial metric perturbations generated during inflation is determined. (orig.)
BOREAS RSS-17 Dielectric Constant Profile Measurements
Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); McDonald, Kyle C.; Zimmerman, Reiner; Way, JoBea
2000-01-01
The BOREAS RSS-17 team acquired and analyzed imaging radar data from the ESA's ERS-1 over a complete annual cycle at the BOREAS sites in Canada in 1994 to detect shifts in radar backscatter related to varying environmental conditions. This data set consists of dielectric constant profile measurements from selected trees at various BOREAS flux tower sites. The relative dielectric constant was measured at C-band (frequency = 5 GHz) as a function of depth into the trunk of three trees at each site, Measurements were made during April 1994 with an Applied Microwave Corporation field PDP fitted with a 0.358-cm (0.141-inch) diameter coaxial probe tip. The data are available in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).
Mixed quantum states with variable Planck constant
de Gosson, Maurice A.
2017-09-01
Recent cosmological measurements tend to confirm that the fine structure constant α is not immutable and has undergone a tiny variation since the Big Bang. Choosing adequate units, this could also reflect a variation of Planck's constant h. The aim of this Letter is to explore some consequences of such a possible change of h for the pure and mixed states of quantum mechanics. Surprisingly enough it is found that not only is the purity of a state extremely sensitive to such changes, but that quantum states can evolve into classical states, and vice versa. A complete classification of such transitions is however not possible for the moment being because of yet unsolved mathematical difficulties related to the study of positivity properties of trace class operators.
Benjamin Constant. Libertad, democracia y pluralismo
Directory of Open Access Journals (Sweden)
Claudia Patricia Fonnegra Osorio
2015-12-01
Full Text Available A partir de un enfoque interpretativo, en este artículo se aborda por qué para Benjamin Constant la democracia solo puede darse en donde se presenta una relación necesaria entre la libertad entendida como defensa de los derechos individuales -libertad como independencia o negativa- y la libertad concebida como principio de la participación pública -libertad como autonomía o positiva-. Asimismo, se presenta la importancia que atribuye el autor a las tradiciones que dan vida a la configuración del universo cultural de un pueblo. Se concluye que en la obra de Constant se encuentra una clara defensa del Estado de derecho y del pluralismo, la cual puede iluminar la comprensión de los problemas políticos de la contemporaneidad.
Some Dynamical Effects of the Cosmological Constant
Axenides, M.; Floratos, E. G.; Perivolaropoulos, L.
Newton's law gets modified in the presence of a cosmological constant by a small repulsive term (antigravity) that is proportional to the distance. Assuming a value of the cosmological constant consistent with the recent SnIa data (Λ~=10-52 m-2), we investigate the significance of this term on various astrophysical scales. We find that on galactic scales or smaller (less than a few tens of kpc), the dynamical effects of the vacuum energy are negligible by several orders of magnitude. On scales of 1 Mpc or larger however we find that the vacuum energy can significantly affect the dynamics. For example we show that the velocity data in the local group of galaxies correspond to galactic masses increased by 35% in the presence of vacuum energy. The effect is even more important on larger low density systems like clusters of galaxies or superclusters.
... Hearing Loss Homepage Facts Noise-Induced Hearing Loss Genetics of Hearing Loss Screening & Diagnosis Types of Hearing Loss About Sound Treatment & Intervention Services Learning Language Bacterial Meningitis Studies Data & Statistics EHDI Annual Data 2015 ...
... Hearing Loss Homepage Facts Noise-Induced Hearing Loss Genetics of Hearing Loss Screening & Diagnosis Types of Hearing Loss About Sound Treatment & Intervention Services Learning Language Bacterial Meningitis Studies Data & Statistics EHDI Annual Data 2015 ...
... page please turn JavaScript on. Feature: Hearing Loss Managing Hearing Loss Past Issues / Spring 2015 Table of ... not a cure. Read More "Hearing Loss" Articles Managing Hearing Loss / Symptoms, Devices, Prevention & Research / Screening Newborns / ...
... Home > Resources > Bone Loss in IBD Go Back Bone Loss in IBD Email Print + Share As many as ... halt bone loss are so important. CAUSES OF BONE LOSS IN IBD Experts point to several suspected causes ...
DEFF Research Database (Denmark)
Petersen, JH; Holst, KK; Budtz-Jørgensen, Esben
2010-01-01
The Hubble constant enters big bang cosmology by quantifying the expansion rate of the universe. Existing statistical methods used to estimate Hubble’s constant only partially take into account random measurement errors. As a consequence, estimates of Hubble’s constant are statistically...
A Non-anthropic Solution to the Cosmological Constant Problem
Directory of Open Access Journals (Sweden)
Spivey R. J.
2016-01-01
Full Text Available Accelerating cosmological expansion is driven by a minuscule vacuum energy density possibly seeking opportunities to decay to a true ground state. Quasar characteristics imply their central engines possess an intrinsic magnetic field compatible with the pres- ence of an electrically charged toroidal dark hole, an eternally collapsing structure lack- ing an event horizon. The possibility is consistent with the inability of black holes to capture particles in a universe of finite age, Einstein’s dismissal of the Schwarzschild metric as unphysical and the implausibility of the various paradoxes invoked by black hole existence. The uncloaked innards of these dark holes would expose immense vac- uum accelerations at their cores, inevitably tempered by Planck scale physics. The Unruh effect predicts that intense yet highly localised heating should occur there. As thermal energy gradually amasses and dissipates, radiation would eventually start to escape into the surrounding environment. Virtual from the d ark hole perspective, the emissions could not decrease the dark hole’s mass: the energy source must instead be the universal vacuum, the likely repository of dark energy. In analogy with core- collapse supernovae, neutrinos should dominate the cooling flows. Red-shifting to low energies upon escape, quantum degenerate haloes should for m predominantly around the largest galaxies. This mechanism is promising from the perspective of enabling the future universe to efficiently sustain aquatic life before stars become scarce, offering a biological yet decidedly non-anthropic solution to the cosmological constant problem.
Electromagnetic corrections to pseudoscalar decay constants
Energy Technology Data Exchange (ETDEWEB)
Glaessle, Benjamin Simon
2017-03-06
First principles Lattice quantum chromodynamics (LQCD) calculations enable the determination of low energy hadronic amplitudes. Precision LQCD calculations with relative errors smaller than approximately 1% require the inclusion of electromagnetic effects. We demonstrate that including (quenched) quantum electrodynamics effects in the LQCD calculation effects the values obtained for pseudoscalar decay constants in the per mille range. The importance of systematic effects, including finite volume effects and the charge dependence of renormalization and improvement coefficients, is highlighted.
Constant load and constant volume response of municipal solid waste in simple shear.
Zekkos, Dimitrios; Fei, Xunchang
2017-05-01
Constant load and constant volume simple shear testing was conducted on relatively fresh municipal solid waste (MSW) from two landfills in the United States, one in Michigan and a second in Texas, at respective natural moisture content below field capacity. The results were assessed in terms of two failure strain criteria, at 10% and 30% shear strain, and two interpretations of effective friction angle. Overall, friction angle obtained assuming that the failure plane is horizontal and at 10% shear strain resulted in a conservative estimation of shear strength of MSW. Comparisons between constant volume and constant load simple shear testing results indicated significant differences in the shear response of MSW with the shear resistance in constant volume being lower than the shear resistance in constant load. The majority of specimens were nearly uncompacted during specimen preparation to reproduce the state of MSW in bioreactor landfills or in uncontrolled waste dumps. The specimens had identical percentage of waste. The results of these tests suggest the possibility of significantly lower shear strength of MSW in bioreactor landfills where waste is placed with low compaction effort and constant volume, i.e., "undrained", conditions may occur. Compacted MSW specimens resulted in shear strength parameters that are higher than uncompacted specimens and closer to values reported in the literature. However, the normalized undrained shear strength in simple shear for uncompacted and compacted MSW was still higher than the normalized undrained shear strength reported in the literature for clayey and silty soils. Copyright © 2016 Elsevier Ltd. All rights reserved.
Relationship of coagulation constant to time
Energy Technology Data Exchange (ETDEWEB)
Nadirov, N.K.; Anisimov, B.F.; Borodkin, L.P.
1982-01-01
Tests were carried out for the purpose of constructing mathematical models of electrodehydration of petroleum. Work was performed in electric fields with constant current. A 1% emulsion ''water in vaseline oil'' was placed into a cell after a 5 minute treatment in a UZDN-1 ultrasound disperser. Distance between electrodes was held at 25 mm. The cell was fed high voltage current from the source (VS-20-10), which was held constant throughout the entire test period. Current was measured with a microampermeter type M266M. Changes in the emulsion were observed using a KM-6 cathetometer. It was shown that the character of changes in function M(t), are dependent on the voltage of the electric field, viscosity of the media, initial concentration and initial distribution of particles according to size. The constant of kinetic coagulation is dependent on time: during the initial moment of electro-treatment of a reverse emulsion, thermal coagulation was observed, which gradually is replaced with electro-gravitational coagulation.
Thermodynamic binding constants for gallium transferrin
Energy Technology Data Exchange (ETDEWEB)
Harris, W.R.; Pecoraro, V.L.
1983-01-18
Gallium-67 is widely used as an imaging agent for tumors and inflammatory abscesses. It is well stablished that Ga/sup 3 +/ travels through the circulatory system bound to the serum iron transport protein transferrin and that this protein binding is an essential step in tumor localization. However, there have been conflicting reports on the magnitude of the gallium-transferrin binding constants. Therefore, thermodynamic binding constants for gallium complexation at the two specific metal binding sites of human serum transferrin at pH 7.4 and 5 mM NaHCO/sub 3/ have been determined by UV difference spectroscopy. The conditional constants calculated for 27 mM NaHCO/sub 3/ are log K/sub 1/* = 20.3 and log K/sub 2/* = 19.3. These results are discussed in relation to the thermodynamics of transferrin binding of Fe/sup 3 +/ and to previous reports on gallium binding. The strength of transferrin complexation is also compared to that of a series of low molecular weight ligands by using calculated pM values (pM = -log (Ga(H/sub 2/O)/sub 6/)) to express the effective binding strength at pH 7.4.
Strain sweeps from Oldroyd 8-constant framework
Saengow, Chaimongkol; Giacomin, Alan Jeffrey
2017-05-01
Large-amplitude oscillatory shear flow is a popular experiment for studying the nonlinear physics of complex fluids. Specifically, the strain sweep is used routinely to identify when a complex fluid begins to exhibit nonlinear behavior. In this paper, we give the exact shear stress expression for the Oldroyd 8-constant framework evaluated for large-amplitude oscillatory shear flow (LAOS). We choose the Oldroyd 8-constant framework for its rich diversity of popular special cases (we list 14 of these cases). From our shear stress expression, we get exact expressions for the real and imaginary parts of the complex viscosity as functions of both the test frequency, and the shear rate amplitude. We then demonstrate the use of our results for our favorite special case of the Oldroyd 8-constant framework, the corotational Jeffreys model. In our Worked Example, we use this case to explore the influence of η∞ on the strain sweep response. We find that increasing η∞ raises the real part of the complex viscosity, and decreases its imaginary part.
Application of dielectric constant measurements to radar imagery interpretation
Bryan, M. L.; Larson, R. W.
1973-01-01
The author has identified the following significant results. Although it is readily recognized that there is a need for ground truth to provide adequate guidance for remote sensing data interpretation, it is noted that, in terms of radar remote sensing, this ground truth is often inadequate. It is necessary to make basic electrical and physical measurements of the surface and to some depth below it. A brief outline is presented of a ground truth scheme which uses measurements of the dielectric constant. Two portable instruments were designed specifically for this purpose; these were: (1) a Q-meter for measurement of dielectric constant and loss tangent; and (2) an instrument to measure electrical properties of the two operating frequencies of the imaging radar. Although extensive data are lacking, several general cases of radar-earth surface and interaction are described; also, examples of radar imagery and some data on ice and snow are presented. It is concluded that the next logical step is to begin to quantify the radar ground truth in preparation for machine interpretation and automatic data processing of the radar imagery.
Directory of Open Access Journals (Sweden)
Abel W. de Albuquerque
2005-06-01
Full Text Available Para se alcançar os objetivos previstos neste trabalho, determinaram-se os fatores da Equação Universal de Perda de Solo (EUPS em condições de chuva natural, num Luvissolo de Sumé, PB, em que os dados relativos aos anos de 1983-1990 foram obtidos na Estação Experimental de Sumé, PB, pertencente à Universidade Federal da Paraíba - UFPB, cujos tratamentos foram os seguintes: parcela descoberta e em alqueive contínuo, parcela com caatinga nativa, parcela com caatinga nova, parcelas em pousio, parcela com palma cultivada morro abaixo e parcela com palma cultivada em nível. Os valores médios anuais do fator erosividade da chuva expressos em EI30 e PI30 foram de 4.928 MJ mm ha-1 h-1 e 19.734 mm-2 h-1, respectivamente. Os valores do fator erodibilidade do solo (K foram calculados em 0,013 t h MJ-1 mm-1 e 0,003 t ha-1 mm-2, enquanto os valores determinados para o fator uso e manejo do solo foram os seguintes: 0,0015 (caatinga nativa, 0,0174 (caatinga nova, 0,0133 (cobertura morta, 0,0056 (cobertura morta, 0,5103 (palma cultivada morro abaixo e 0,2355 (palma cultivada em nível. O valor do fator práticas conservacionistas para palma cultivada em nível foi de 0,46The Universal Soil Loss Equation (USLE factors were determined in a Haplargs under natural rainfall conditions. Data concerning to the years of 1983 -1990 were obtained at the Sumé Experimental Station (Paraíba State - Brazil of the Federal University of Paraíba (UFPB. The treatments consisted of runoff plots with bare soil, native semiarid vegetation runoff plot, mulch runoff plot, palm leaf under downhill runoff plot and under contour palm leaf runoff plot. The annual average of the rainfall erosivity factors EI30 and PI30 were 4,928 MJ mm ha-1 h-1 and 19,734 mm-2 h-1, respectively. The calculated annual mean values of the erodibility parameters were calculated in 0.013 t h MJ-1 mm-1 and 0.003 t h ha-1 mm-2. The calculated values for the support practice factor cropping
Universal spacetimes in four dimensions
Hervik, S.; Pravda, V.; Pravdová, A.
2017-10-01
Universal spacetimes are exact solutions to all higher-order theories of gravity. We study these spacetimes in four dimensions and provide necessary and sufficient conditions for universality for all Petrov types except of type II. We show that all universal spacetimes in four dimensions are algebraically special and Kundt. Petrov type D universal spacetimes are necessarily direct products of two 2-spaces of constant and equal curvature. Furthermore, type II universal spacetimes necessarily possess a null recurrent direction and they admit the above type D direct product metrics as a limit. Such spacetimes represent gravitational waves propagating on these backgrounds. Type III universal spacetimes are also investigated. We determine necessary and sufficient conditions for universality and present an explicit example of a type III universal Kundt non-recurrent metric.
Pediatric Sudden Sensorineural Hearing Loss.
Kizilay, Ahmet; Koca, Çiğdem Firat
2016-06-01
Sudden sensorineural hearing loss is defined as sudden unilateral or bilateral sensorineural hearing loss with at least 30 dB decrease in threshold in 3 contiguous test frequencies occurring over 72 hours or less. It is rare among children. The mechanism of the process and prognosis of the disorder remains unclear. The current incidence of sudden sensorineural hearing loss among pediatric population is unknown. The authors carried out a retrospective chart analysis of patients under 15 years of age from 2004 to 2015, who consulted to the Otolaryngology Head and Neck Surgery Department of Inonu University Medical Faculty. Age, sex, number of affected ear and side, audiometric evaluations, medical follow-up, treatment method, duration of treatment recovery, associated complaints; tinnitus and/or vertigo, presence of mumps disease were recorded for each patient. A 4-frequency pure-tone average (500, 1000, 2000, and 4000 Hz) was calculated for each ear. Complete recovery, defined as some hearing level compared with the nonaffected ear, was observed in 3 patients (21.4 %) and there was no partial hearing recovery. The hearing loss of 11 patient remained unchanged after prednisolone treatment. Two of the 11 patients had bilaterally total sensorineural hearing loss and evaluated as appropriate for cochlear implantation. Sex of patient and laterality of hearing loss were not correlated with hearing recovery. Sensorineural hearing loss among pediatrics has been the issue of otolaryngologists. The incidence, etiology, and treatment methods should be more studied.
Analysis of the chemical equilibrium of combustion at constant volume
Marius BREBENEL
2014-01-01
Determining the composition of a mixture of combustion gases at a given temperature is based on chemical equilibrium, when the equilibrium constants are calculated on the assumption of constant pressure and temperature. In this paper, an analysis of changes occurring when combustion takes place at constant volume is presented, deriving a specific formula of the equilibrium constant. The simple reaction of carbon combustion in pure oxygen in both cases (constant pressure and constant ...
energy and economic losses due to constant power outages in nigeria
African Journals Online (AJOL)
2012-07-02
Jul 2, 2012 ... from Afam power station were assessed based on real data obtained through survey of companies, oral interview, individuals and also .... as Japan [7], Canada [8] and Brazil [9], respectively. Exergy calculation. By describing the .... Tasks such as space heating, heating in industrial furnaces, process steam ...
Relaxing the cosmological constant: a proof of concept
Energy Technology Data Exchange (ETDEWEB)
Alberte, Lasma [SISSA,Via Bonomea 265, 34136 Trieste (Italy); INFN - Sezione di Trieste,Via Valerio 2, 34127 Trieste (Italy); Creminelli, Paolo; Khmelnitsky, Andrei [Abdus Salam International Centre for Theoretical Physics (ICTP),Strada Costiera 11, 34151, Trieste (Italy); Pirtskhalava, David [Institute of Physics, École Polytechnique Fédérale de Lausanne,CH-1015, Lausanne (Switzerland); Trincherini, Enrico [Scuola Normale Superiore,Piazza dei Cavalieri 7, 56126, Pisa (Italy); INFN - Sezione di Pisa,56200, Pisa (Italy)
2016-12-06
We propose a technically natural scenario whereby an initially large cosmological constant (c.c.) is relaxed down to the observed value due to the dynamics of a scalar evolving on a very shallow potential. The model crucially relies on a sector that violates the null energy condition (NEC) and gets activated only when the Hubble rate becomes sufficiently small — of the order of the present one. As a result of NEC violation, this low-energy universe evolves into inflation, followed by reheating and the standard Big Bang cosmology. The symmetries of the theory force the c.c. to be the same before and after the NEC-violating phase, so that a late-time observer sees an effective c.c. of the correct magnitude. Importantly, our model allows neither for eternal inflation nor for a set of possible values of dark energy, the latter fixed by the parameters of the theory.
Predicting the Cosmological Constant from the Causal Entropic Principle
Energy Technology Data Exchange (ETDEWEB)
Bousso, Raphael; Bousso, Raphael; Harnik, Roni; Kribs, Graham D.; Perez, Gilad
2007-05-01
We compute the expected value of the cosmological constant in our universe from the Causal Entropic Principle. Since observers must obey the laws of thermodynamics and causality, the principle asserts that physical parameters are most likely to be found in the range of values for which the total entropy production within a causally connected region is maximized. Despite the absence of more explicit anthropic criteria, the resulting probability distribution turns out to be in excellent agreement with observation. In particular, we find that dust heated by stars dominates the entropy production, demonstrating the remarkable power of this thermodynamic selection criterion. The alternative approach-weighting by the number of"observers per baryon" -- is less well-defined, requires problematic assumptions about the nature of observers, and yet prefers values larger than present experimental bounds.
Predicting the Cosmological Constant from the CausalEntropic Principle
Energy Technology Data Exchange (ETDEWEB)
Bousso, Raphael; Harnik, Roni; Kribs, Graham D.; Perez, Gilad
2007-02-20
We compute the expected value of the cosmological constant in our universe from the Causal Entropic Principle. Since observers must obey the laws of thermodynamics and causality, it asserts that physical parameters are most likely to be found in the range of values for which the total entropy production within a causally connected region is maximized. Despite the absence of more explicit anthropic criteria, the resulting probability distribution turns out to be in excellent agreement with observation. In particular, we find that dust heated by stars dominates the entropy production, demonstrating the remarkable power of this thermodynamic selection criterion. The alternative approach--weighting by the number of ''observers per baryon''--is less well-defined, requires problematic assumptions about the nature of observers, and yet prefers values larger than present experimental bounds.
Relaxing the cosmological constant: a proof of concept
Alberte, Lasma; Creminelli, Paolo; Khmelnitsky, Andrei; Pirtskhalava, David; Trincherini, Enrico
2016-12-01
We propose a technically natural scenario whereby an initially large cosmological constant (c.c.) is relaxed down to the observed value due to the dynamics of a scalar evolving on a very shallow potential. The model crucially relies on a sector that violates the null energy condition (NEC) and gets activated only when the Hubble rate becomes sufficiently small — of the order of the present one. As a result of NEC violation, this low-energy universe evolves into inflation, followed by reheating and the standard Big Bang cosmology. The symmetries of the theory force the c.c. to be the same before and after the NEC-violating phase, so that a late-time observer sees an effective c.c. of the correct magnitude. Importantly, our model allows neither for eternal inflation nor for a set of possible values of dark energy, the latter fixed by the parameters of the theory.
Is the island universe model consistent with observations?
Piao, Yun-Song
2005-01-01
We study the island universe model, in which initially the universe is in a cosmological constant sea, then the local quantum fluctuations violating the null energy condition create the islands of matter, some of which might corresponds to our observable universe. We examine the possibility that the island universe model is regarded as an alternative scenario of the origin of observable universe.
Energy Technology Data Exchange (ETDEWEB)
Cavcar, A.; Cavcar, M. [Anadolu Univ., School of Civil Aviation, Eskisehir, (Turkey)
2004-09-01
Approximate cruise range solutions are introduced for the constant altitude constant high subsonic speed flight of turbojet/fan transport aircraft with cambered wing design. The variation of the specific fuel consumption with Mach number is also considered in derivation of the approximate solutions. The method aims at estimation of the cruise range of aircraft during conceptual or preliminary design phase. An application of the solutions is also presented. (author)
Black Holes and Quantum Theory: The Fine Structure Constant Connection
Directory of Open Access Journals (Sweden)
Cahill R. T.
2006-10-01
Full Text Available The new dynamical theory of space is further confirmed by showing that the effective “black hole” masses M BH in 19 spherical star systems, from globular clusters to galaxies, with masses M , satisfy the prediction that M BH = α 2 M , where α is the fine structure constant. As well the necessary and unique generalisations of the Schr ̈ odinger and Dirac equations permit the first derivation of gravity from a deeper theory, showing that gravity is a quantum effect of quantum matter interacting with the dynamical space. As well the necessary generalisation of Maxwell’s equations displays the observed light bending effects. Finally it is shown from the generalised Dirac equation where the spacetime mathematical formalism, and the accompanying geodesic prescription for matter trajectories, comes from. The new theory of space is non-local and we see many parallels between this and quantum theory, in addition to the fine structure constant manifesting in both, so supporting the argument that space is a quantum foam system, as implied by the deeper information-theoretic theory known as Process Physics. The spatial dynamics also provides an explanation for the “dark matter” effect and as well the non-locality of the dynamics provides a mechanism for generating the uniformity of the universe, so explaining the cosmological horizon problem.
Metamorphosis of the cosmological constant and 5D origin of the fiducial metric
Gabadadze, Gregory; Yu, Siqing
2016-11-01
In a recently proposed theory, the cosmological constant (CC) does not curve spacetime in our Universe, but instead gets absorbed into another universe endowed with its own dynamical metric, nonlocally coupled to ours. Thus, one achieves a long standing goal of removing entirely any cosmological constant from our Universe. Dark energy then cannot be due to a cosmological constant, but must be obtained via other mechanisms. Here we focus on the scenario in which dark energy is due to massive gravity and its extensions. We show how the metric of the other universe, that absorbs our CC, also gives rise to the fiducial metric known to be necessary for the diffeomorphism invariant formulation of massive gravity. This is achieved in a framework where the other universe is described by 5D AdS gravity, while our Universe lives on its boundary and is endowed with dynamical massive gravity. A nondynamical pullback of the bulk AdS metric acts as the fiducial metric for massive gravity on the boundary. This framework also removes a difficulty caused by the quantum strongly coupled behavior of massive gravity at the Λ3 scale: in the present approach, the massive gravity action does not receive any loop-induced counterterms, despite being strongly coupled.
CONSTANT LEVERAGE AND CONSTANT COST OF CAPITAL: A COMMON KNOWLEDGE HALF-TRUTH
Directory of Open Access Journals (Sweden)
IGNACIO VÉLEZ-PAREJA
2008-01-01
Full Text Available Un enfoque típico para valorar flujos de caja finitos es suponer que el endeudamiento es constante (generalmente como un endeudamiento objetivo o deseado y que por tanto, el costo del patrimonio, Ke y el costo promedio ponderado de capital CPPC, también son constantes. Para los flujos de caja perpetuos, y con el costo de la deuda, Kd como la tasa de descuento para el ahorro en impuestos o escudo fiscal, Ke y el CPPC aplicado al flujo de caja libre FCL son constantes si el endeudamiento es constante. Sin embargo esto no es verdad para los flujos de caja finitos. En este documento mostramos que para flujos de caja finitos, Ke y por lo tanto el CPPC dependen de la tasa de descuento que se utiliza para valorar el ahorro en impuestos, AI y según lo esperado, Ke y el CPPC no son constantes con Kd como la tasa de descuento para el ahorro en impuestos, aunque el endeudamiento sea constante. Ilustramos esta situación con un ejemplo simple. Analizamos cinco métodos: el flujo de caja descontado, FCD, usando APV, el FCD y la formulación tradicional y general del CPPC, el valor presente del flujo de caja del accionista, FCA más deuda y el flujo de caja de capital, FCC.
Sample variance in the local measurements of the Hubble constant
Wu, Hao-Yi; Huterer, Dragan
2017-11-01
The current >3σ tension between the Hubble constant H0 measured from local distance indicators and from cosmic microwave background is one of the most highly debated issues in cosmology, as it possibly indicates new physics or unknown systematics. In this work, we explore whether this tension can be alleviated by the sample variance in the local measurements, which use a small fraction of the Hubble volume. We use a large-volume cosmological N-body simulation to model the local measurements and to quantify the variance due to local density fluctuations and sample selection. We explicitly take into account the inhomogeneous spatial distribution of type Ia supernovae. Despite the faithful modelling of the observations, our results confirm previous findings that sample variance in the local Hubble constant (H_0^loc) measurements is small; we find σ (H_0^loc)=0.31 {km s^{-1}Mpc^{-1}}, a nearly negligible fraction of the ˜6 km s-1Mpc-1 necessary to explain the difference between the local and global H0 measurements. While the H0 tension could in principle be explained by our local neighbourhood being a underdense region of radius ˜150 Mpc, the extreme required underdensity of such a void (δ ≃ -0.8) makes it very unlikely in a ΛCDM universe, and it also violates existing observational constraints. Therefore, sample variance in a ΛCDM universe cannot appreciably alleviate the tension in H0 measurements even after taking into account the inhomogeneous selection of type Ia supernovae.
Rate constants, timescales, and free energy barriers
Salamon, Peter; Wales, David; Segall, Anca; Lai, Yi-An; Schön, J. Christian; Hoffmann, Karl Heinz; Andresen, Bjarne
2016-01-01
The traditional connection between rate constants and free energy landscapes is extended to define effective free energy landscapes relevant on any chosen timescale. Although the Eyring-Polanyi transition state theory specifies a fixed timescale of τ=h/kBT}, we introduce instead the timescale of interest for the system in question, e.g. the observation time. The utility of drawing such landscapes using a variety of timescales is illustrated by the example of Holliday junction resolution. The resulting free energy landscapes are easier to interpret, clearly reveal observation time dependent effects like coalescence of short-lived states, and reveal features of interest for the specific system more clearly.
Radiation balances and the solar constant
Crommelynck, D.
1981-01-01
The radiometric concepts are defined in order to consider various types of radiation balances and relate them to the diabetic form of the energy balance. Variability in space and time of the components of the radiation field are presented. A specific concept for sweeping which is tailored to the requirements is proposed. Finally, after establishing the truncated character of the present knowledge of the radiation balance. The results of the last observations of the solar constant are given. Ground and satellite measurement techniques are discussed.
TASI Lectures on the cosmological constant
Energy Technology Data Exchange (ETDEWEB)
Bousso, Raphael; Bousso, Raphael
2007-08-30
The energy density of the vacuum, Lambda, is at least 60 orders of magnitude smaller than several known contributions to it. Approaches to this problem are tightly constrained by data ranging from elementary observations to precision experiments. Absent overwhelming evidence to the contrary, dark energy can only be interpreted as vacuum energy, so the venerable assumption that Lambda=0 conflicts with observation. The possibility remains that Lambda is fundamentally variable, though constant over large spacetime regions. This can explain the observed value, but only in a theory satisfying a number of restrictive kinematic and dynamical conditions. String theory offers a concrete realization through its landscape of metastable vacua.
Dynamical systems defining Jacobi's θ-constants
Brezhnev, Yurii V.; Lyakhovich, Simon L.; Sharapov, Alexey A.
2011-11-01
We propose a system of equations that defines Weierstrass-Jacobi's eta- and theta-constant series in a differentially closed way. This system is shown to have a direct relationship to a little-known dynamical system obtained by Jacobi. The classically known differential equations by Darboux-Halphen, Chazy, and Ramanujan are the differential consequences or reductions of these systems. The proposed system is shown to admit the Lagrangian, Hamiltonian, and Nambu formulations. We explicitly construct a pencil of nonlinear Poisson brackets and complete set of involutive conserved quantities. As byproducts of the theory, we exemplify conserved quantities for the Ramamani dynamical system and quadratic system of Halphen-Brioschi.
Distributed Link Scheduling with Constant Overhead
Sanghavi, Sujay; Bui, Loc; Srikant, R.
2006-01-01
This paper proposes a new class of simple, distributed algorithms for scheduling in wireless networks. The algorithms generate new schedules in a distributed manner via simple local changes to existing schedules. The class is parameterized by integers $k\\geq 1$. We show that algorithm $k$ of our class achieves $k/(k+2)$ of the capacity region, for every $k\\geq 1$. The algorithms have small and constant worst-case overheads: in particular, algorithm $k$ generates a new schedule using {\\em (a)}...
Can the cosmological constant undergo abrupt changes?
Cabo-Montes de Oca, Alejandro; Rosabal, A; Cabo, Alejandro; Garcia-Chung, Alejandro; Rosabal, Alejandro
2005-01-01
The existence of a simple spherically symmetric and static solution of the Einstein equations in the presence of a cosmological constant vanishing outside a definite value of the radial distance is investigated. A particular succession of field configurations, which are solutions of the Einstein equations in the presence of the considered cosmological term and auxiliary external sources, is constructed. Then, it is shown that the associated succession of external sources tend to zero in the sense of the generalized functions. The type of weak solution that is found becomes the deSitter homogeneous space-time for the interior region, and the Schwartzschild space in the outside zone.
On inflation, cosmological constant, and SUSY breaking
Energy Technology Data Exchange (ETDEWEB)
Linde, Andrei [Department of Physics and SITP, Stanford University, Stanford, California 94305 (United States)
2016-11-02
We consider a broad class of inflationary models of two unconstrained chiral superfields, the stabilizer S and the inflaton Φ, which can describe inflationary models with nearly arbitrary potentials. These models include, in particular, the recently introduced theories of cosmological attractors, which provide an excellent fit to the latest Planck data. We show that by adding to the superpotential of the fields S and Φ a small term depending on a nilpotent chiral superfield P one can break SUSY and introduce a small cosmological constant without affecting main predictions of the original inflationary scenario.
Type Ia Supernovae Progenitor Problem and the Variation of Fundamental Constants
Directory of Open Access Journals (Sweden)
Rybicki M.
2016-01-01
Full Text Available Cosmological observations strongly suggest our universe is the interior of an expanding black hole. If the constant mass of the universe is assumed then from the equation for Schwarzschild radius: r S = 2 Gmc it follows that proportionality constant Gc depends linearly on the universe’s radius R u , identified with r S , i.e. Gc Because the Chandrasekhar limit M Ch relates to the speed of light and to the Newton’s constant as M Ch ( c = G 3 = 2 so expansion involves gradual decrease of M Ch . In result, a single white dwarf can alone become the Type Ia supernova progenitor, which provides a complementary solution to single-degenerate and double-degenerate models for SNe Ia. Both alternative scenarios: G R u and c R are analyzed in regard of their consistence with observations, and their consequences to cosmology.
The Weierstrass Criterion and the LEMAÎTRE-TOLMAN-BONDI Models with Cosmological Constant Λ
Bochicchio, Ivana; Capozziello, Salvatore; Laserra, Ettore
We analyze Lemaitre-Tolman-Bondi models in presence of the cosmological constant \\Lambda through the classical Weierstrass criterion. Precisely, we show that the Weierstrass approach allows us to classify the dynamics of these inhomogeneous spherically symmetric Universes taking into account their relationship with the sign of \\Lambda.
Directory of Open Access Journals (Sweden)
Dariusz Sośnicki
2011-01-01
Full Text Available In his piece, the author of the article ponders on the experience of loss in human life. It is this particular experience, as well as the accompanying longing, that form the basic components of an elegiac attitude. However, in its broader sense, loss becomes one of the most universal experiences in literature and the arts of the twentieth century. After all, they shared the conviction that reality, no matter how looked upon, was never fully accessible to us and that man always played a losing game with it. Contrary to outward appearances, the above also applies to the creators of avant-garde movements. An analysis of the poem Do NN***, written by Miron Białoszewski, carried out first within the context of elegy and then with reference to the techniques and the program of cubism, makes us aware that Białoszewski somehow evades both elegiac mood and the avant-garde principles such as they are underlined in its program. The driving force for his writing is then curiosity. And it is curiosity, and just curiosity, independent and one that cannot be reduced to just the desire to know, that forms the only real alternative that, in a way, always remains metaphysical.
Energy Technology Data Exchange (ETDEWEB)
Osborne, David; Lawson, Patrick; Adams, Nigel, E-mail: ngadams@uga.edu [University of Georgia, Department of Chemistry, 101 Cedar St., Athens, Georgia 30602 (United States)
2014-01-21
Following the arrival of Cassini at Titan in 2004, the Titan atmosphere has been shown to contain large complex polycyclic-aromatic hydrocarbons. Since Cassini has provided a great deal of data, there exists a need for kinetic rate data to help with modeling this atmosphere. One type of kinetic data needed is electron-ion dissociative recombination (e-IDR) rate constants. These data are not readily available for larger compounds, such as naphthalene, or oxygen containing compounds, such as 1,4 dioxane or furan. Here, the rate constants for naphthalene, 1,4 dioxane, and furan have been measured and their temperature dependencies are determined when possible, using the University of Georgia's Variable Temperature Flowing Afterglow. The rate constants are compared with those previously published for other compounds; these show trends which illustrate the effects which multi-rings and oxygen heteroatoms substitutions have upon e-IDR rate constants.
P.J. Collins (Pieter)
2006-01-01
textabstractA flow in three-dimensions is universal if the periodic orbits contains all knots and links. Universal flows were shown to exist by Ghrist, and can be constructed by means of templates. Likewise, a planar diffeomorphism is universal if it has a suspension flow which is a universal flow.
Directory of Open Access Journals (Sweden)
Jean Paolo Gomes Minella
2010-08-01
Full Text Available Métodos de representação espacial para o cálculo do fator topográfico (LS da Equação Universal de Perda de Solo Revisada (RUSLE têm sido utilizados para estimar a erosão do solo e a produção de sedimentos em bacias hidrográficas. Esses procedimentos baseiam-se nas equações tradicionalmente empregadas para determinação do fator LS e em informações que caracterizam a forma das vertentes derivadas do modelo numérico de elevação (MNE. Neste estudo foram analisados dois métodos de representação espacial utilizados no cálculo do fator LS em modelos matemáticos de erosão e produção de sedimentos em bacias hidrográficas. A análise foi realizada em quatro bacias rurais de relevo movimentado. Os valores de LS obtidos pelos métodos de representação espacial foram comparados entre si e com valores de LS determinados pelo método tradicional com levantamento em campo. Resultados mostraram que os valores de LS gerados pelos métodos de representação espacial apresentam diferenças significativas entre si, sendo dependentes do procedimento de cálculo e do método utilizado para determinar a direção de fluxo no MNE. Também foi verificado que os valores numéricos do fator LS determinados pelos métodos de representação espacial apresentam diferenças em relação àqueles estimados pelo método tradicional.Methods of spatial representation to calculate the topographic factor (LS of the Revised Universal Soil Loss Equation (USLE have been used to estimate soil erosion and sediment yield of watersheds. These procedures are based on equations traditionally used to determine the LS factor and information that characterize the hillslope forms and processes, derived from the Digital Elevation Model (DEM. Two computational methods commonly used to calculate LS factor in soil erosion and sediment yield models were analyzed in this study. The analysis was performed in four small rural watersheds with hilly terrain. The LS values
Superintegrable systems on spaces of constant curvature
Energy Technology Data Exchange (ETDEWEB)
Gonera, Cezary, E-mail: cgonera@uni.lodz.pl; Kaszubska, Magdalena
2014-07-15
Construction and classification of two-dimensional (2D) superintegrable systems (i.e. systems admitting, in addition to two global integrals of motion guaranteeing the Liouville integrability, the third global and independent one) defined on 2D spaces of constant curvature and separable in the so-called geodesic polar coordinates are presented. The method proposed is applicable to any value of curvature including the case of Euclidean plane, sphere and hyperbolic plane. The main result is a generalization of Bertrand’s theorem on 2D spaces of constant curvature and covers most of the known separable and superintegrable models on such spaces (in particular, the so-called Tremblay–Turbiner–Winternitz (TTW) and Post–Winternitz (PW) models which have recently attracted some interest). -- Highlights: •Classifying 2D superintegrable, separable (polar coordinates) systems on S{sup 2}, R{sup 2}, H{sup 2}. •Construction of radial, angular potentials leading to superintegrability. •Generalization of Bertrand’s theorem covering known models, e.g. Higgs, TTW, PW, and Coulomb.
Local Pain Dynamics during Constant Exhaustive Exercise.
Directory of Open Access Journals (Sweden)
Agne Slapsinskaite
Full Text Available The purpose of this study was to delineate the topological dynamics of pain and discomfort during constant exercise performed until volitional exhaustion. Eleven physical education students were tested while cycling and running at a "hard" intensity level (e.g., corresponding to Borg's RPE (6-20 = 15. During the tests, participants reported their discomfort and pain on a body map every 15s. "Time on task" for each participant was divided into five equal non-overlapping temporal windows within which their ratings were considered for analysis. The analyses revealed that the number of body locations with perceived pain and discomfort increased throughout the five temporal windows until reaching the mean (± SE values of 4.2 ± 0.7 and 4.1 ± 0.6 in cycling and running, respectively. The dominant locations included the quadriceps and hamstrings during cycling and quadriceps and chest during running. In conclusion, pain seemed to spread throughout the body during constant cycling and running performed up to volitional exhaustion with differences between cycling and running in the upper body but not in the lower body dynamics.
Magnetized anisotropic dark energy models with constant ...
Indian Academy of Sciences (India)
In this paper, we have studied the solutions of plane-symmetric Universe with variable ω in the presence and the absence of magnetic field of energy density ρ B . A special law of variation for Hubble's parameterproposed by Bermann in {\\it Nuovo Cimento} B 74, 182 (1983) has been utilized to solve the field equations.
Yesterday, Today and Tomorrow--Constant Change
Reader, Peter
2011-01-01
It is not so long ago that universities shunned words such as "public relations" and "marketing," preferring to describe staff working in these areas as information officers and even assistant registrars and with such staff drawn from a cadre of generalist administrators. If they really had to be specific, then an acceptable word was "publicity".…
CLASSICAL CEPHEIDS REQUIRE ENHANCED MASS LOSS
Energy Technology Data Exchange (ETDEWEB)
Neilson, Hilding R.; Langer, Norbert; Izzard, Robert [Argelander Institute for Astronomy, University of Bonn, Auf dem Huegel 71, D-53121 Bonn (Germany); Engle, Scott G.; Guinan, Ed, E-mail: neilsonh@etsu.edu [Department of Astronomy and Astrophysics, Villanova University, 800 Lancaster Ave. Villanova, PA 19085 (United States)
2012-11-20
Measurements of rates of period change of Classical Cepheids probe stellar physics and evolution. Additionally, better understanding of Cepheid structure and evolution provides greater insight into their use as standard candles and tools for measuring the Hubble constant. Our recent study of the period change of the nearest Cepheid, Polaris, suggested that it is undergoing enhanced mass loss when compared to canonical stellar evolution model predictions. In this work, we expand the analysis to rates of period change measured for about 200 Galactic Cepheids and compare them to population synthesis models of Cepheids including convective core overshooting and enhanced mass loss. Rates of period change predicted from stellar evolution models without mass loss do not agree with observed rates, whereas including enhanced mass loss yields predicted rates in better agreement with observations. This is the first evidence that enhanced mass loss as suggested previously for Polaris and {delta} Cephei must be a ubiquitous property of Classical Cepheids.
Defect Motifs for Constant Mean Curvature Surfaces
Kusumaatmaja, Halim; Wales, David J.
2013-04-01
The energy landscapes of electrostatically charged particles embedded on constant mean curvature surfaces are analyzed for a wide range of system size, curvature, and interaction potentials. The surfaces are taken to be rigid, and the basin-hopping method is used to locate the putative global minimum structures. The defect motifs favored by potential energy agree with experimental observations for colloidal systems: extended defects (scars and pleats) for weakly positive and negative Gaussian curvatures, and isolated defects for strongly negative Gaussian curvatures. Near the phase boundary between these regimes, the two motifs are in strong competition, as evidenced from the appearance of distinct funnels in the potential energy landscape. We also report a novel defect motif consisting of pentagon pairs.
Measuring the RC time constant with Arduino
Pereira, N. S. A.
2016-11-01
In this work we use the Arduino UNO R3 open source hardware platform to assemble an experimental apparatus for the measurement of the time constant of an RC circuit. With adequate programming, the Arduino is used as a signal generator, a data acquisition system and a basic signal visualisation tool. Theoretical calculations are compared with direct observations from an analogue oscilloscope. Data processing and curve fitting is performed on a spreadsheet. The results obtained for the six RC test circuits are within the expected interval of values defined by the tolerance of the components. The hardware and software prove to be adequate to the proposed measurements and therefore adaptable to a laboratorial teaching and learning context.
... Weight for Me? Your Teeth Heart Murmurs What's Hearing Loss? KidsHealth > For Kids > What's Hearing Loss? Print ... problem can also develop later in life. How Hearing Works To understand how and why hearing loss ...
... Find an ENT Doctor Near You Genes and Hearing Loss Genes and Hearing Loss Patient Health Information News media interested in ... One of the most common birth defects is hearing loss or deafness (congenital), which can affect as ...
Pregnancy Loss and Miscarriage
... Information Find a Study Resources and Publications Pregnancy Loss: Condition Information Skip sharing on social media links Share this: Page Content What is pregnancy loss/miscarriage? A miscarriage, also called pregnancy loss or ...
... up bone loss. After menopause your ovaries stop producing the hormone estrogen, which helps to keep your ... you minimize and treat bone loss? Diet and lifestyle can help prevent and treat bone loss. Successful ...
Gkigkitzis, Ioannis; Haranas, Ioannis; Kirk, Samantha
2013-12-01
Using a recent published formula for the number of information N that results from Landauer's principle we obtain an expression for the cosmological constant Λ. Next, assuming the universe as a system of mass M satisfying Landauer's principle and eliminating its mass M from the given expression for the number of information, we obtain a new expression that agrees with the expression derived by Lloyd. Furthermore, we modify the generalized entropy relation and three equivalent entropy expressions are obtained. Finally, in two different universes the time rate of change of the entropy is calculated. In a flat universe the time rate of the entropy is time independent and depends on fundamental constants of physics.
Constant Leverage And Constant Cost Of Capital: A Common Knowledge Half-Truth
Directory of Open Access Journals (Sweden)
Ignacio Vélez–Pareja
2008-04-01
In this document we show that for finite cash flows, Ke and hence WACC depend on the discount rate that is used to value the tax shield, TS and as expected, Ke and WACC are not constant with Kd as the discount rate for the tax shield, even if the leverage is constant. We illustrate this situation with a simple example. We analyze five methods: DCF using APV, FCF and traditional and general formulation for WACC, present value of CFE plus debt and Capital Cash Flow, CCF.
Economic Loan Loss Provision and Expected Loss
Directory of Open Access Journals (Sweden)
Stefan Hlawatsch
2010-10-01
Full Text Available The intention of a loan loss provision is the anticipation of the loan's expected losses by adjusting the book value of the loan. Furthermore, this loan loss provision has to be compared to the expected loss according to Basel II and, in the case of a difference, liable equity has to be adjusted. This however assumes that the loan loss provision and the expected loss are based on a similar economic rationale, which is only valid conditionally in current loan loss provisioning methods according to IFRS. Therefore, differences between loan loss provisions and expected losses should only result from different approaches regarding the parameter estimation within each model and not due to different assumptions regarding the outcome of the model. The provisioning and accounting model developed in this paper overcomes the before-mentioned shortcomings and is consistent with an economic rationale of expected losses. Additionally, this model is based on a close-to-market valuation of the loan that is in favor of the basic idea of IFRS. Suggestions for changes in current accounting and capital requirement rules are provided.
A Universe without Weak Interactions
Energy Technology Data Exchange (ETDEWEB)
Harnik, Roni; Kribs, Graham D.; Perez, Gilad
2006-04-07
A universe without weak interactions is constructed that undergoes big-bang nucleosynthesis, matter domination, structure formation, and star formation. The stars in this universe are able to burn for billions of years, synthesize elements up to iron, and undergo supernova explosions, dispersing heavy elements into the interstellar medium. These definitive claims are supported by a detailed analysis where this hypothetical ''Weakless Universe'' is matched to our Universe by simultaneously adjusting Standard Model and cosmological parameters. For instance, chemistry and nuclear physics are essentially unchanged. The apparent habitability of the Weakless Universe suggests that the anthropic principle does not determine the scale of electroweak breaking, or even require that it be smaller than the Planck scale, so long as technically natural parameters may be suitably adjusted. Whether the multi-parameter adjustment is realized or probable is dependent on the ultraviolet completion, such as the string landscape. Considering a similar analysis for the cosmological constant, however, we argue that no adjustments of other parameters are able to allow the cosmological constant to raise up even remotely close to the Planck scale while obtaining macroscopic structure. The fine-tuning problems associated with the electroweak breaking scale and the cosmological constant therefore appear to be qualitatively different from the perspective of obtaining a habitable universe.
2002-01-01
This report contains translations of eight papers published in the Nuclear Constants journal (Voprosy Atomnoj Nauki I Teknniki, seriya: Yadernye Konstanty (YK), vypusk 1, 2001). They are marked as 'Translated from Russian'. Six original papers published in YK in English are included with correction of found misprints and small format changes. As a result the report contains all papers presented in YK, 1 (2001).
A Solution to Cosmological Constant, Dark Matter, and Dark Energy Problems
Avtar-Singh, S C
2004-01-01
The observed spontaneity in nature, specifically the spontaneous decay of particles, has been mathematically treated in the formulation of a Gravity Nullification model (GNM). GNM is combined with the classical gravitation model and the general theory of relativity to model the universe expansion. This model eliminates singularities in the existing Big Bang model of the universe, predicts effects of gravity on the observed mass evolution, dark matter/energy, and accelerated expansion of the universe. GNM provides a physical understanding of the shortcomings of the Big Bang model such as the Cosmological Constant problems, puzzles of dark matter or dark energy without the need for the incredible inflation scenario involving a “superluminal expansion” of the universe in its early evolution. A mathematical expression is derived for the Anti-gravity Cosmological parameter including the effects of mass and gravity. A good agreement is seen with the recent observations of the universe behavior.
Symmetry breakdown and coupling constants of leptons
Directory of Open Access Journals (Sweden)
Gil C. Marques
2007-06-01
Full Text Available Based on a new approach to symmetries of the fundamental interactions we deal, in this paper, with the electroweak interactions of leptons. We show that the coupling constants, arising in the way leptons are coupled to intermediate bosons, can be understood as parameters associated to the breakdown of SU(2 and parity symmetries. The breakdown of both symmetries is characterized by a new parameter (the asymetry parameter of the electroweak interactions. This parameter gives a measure of the strength of breakdown of symmetries. We analyse the behaviour of the theory for three values of this parameter. The most relevant value is the one for which only the electromagnetic interactions do not break parity (the maximally allowed left-right asymetric theory. Maximamally allowed parity asymmetry is a requirement that is met for a value of Weinberg's theta-angle that is quite close to the experimental value of this parameter.Com base em uma formulação nova para simetrias das interações fundamentais nós lidamos, neste trabalho, com interações eletrofracas de leptons. Mostramos que as constantes do acoplamento, associadas aos acoplamentos de bósons intermediários, podem ser entendidas como parâmetros associados à quebra de simetrias SU(2 e paridade. A quebra de ambas as simetrias é caracterizada por um parâmetro novo (o parâmetro de assimetria das interações eletrofracas. Este parâmetro dá uma medida da intensidade com que a simetria é quebrada. Analisamos o comportamento da teoria para três valores deste parâmetro. O valor mais relevante é aquele para o qual apenas as interações eletromagnéticas não quebram a paridade (a teoria assimétrica esquerda-direita permitida da maneira máxima. A assimetria máxima permitida é uma exigência que leva a um ângulo de Weinberg cujo valor é próximo daquele observado experimentalmente.
P.J. Collins (Pieter)
2007-01-01
htmlabstract A ﬂow in three-dimensions is universal if the periodic orbits contains all knots and links. Universal ﬂows were shown to exist by Ghrist, and can be constructed by means of templates. Likewise, a planar diﬀeomorphism is universal if it has a suspension
Dynamical dark energy with a constant vacuum energy density
Energy Technology Data Exchange (ETDEWEB)
Guberina, B. [Rudjer Boskovic Institute, PO Box 180, 10002 Zagreb (Croatia)]. E-mail: guberina@thphys.irb.hr; Horvat, R. [Rudjer Boskovic Institute, PO Box 180, 10002 Zagreb (Croatia)]. E-mail: horvat@lei3.irb.hr; Nikolic, H. [Rudjer Boskovic Institute, PO Box 180, 10002 Zagreb (Croatia)]. E-mail: hrvoje@thphys.irb.hr
2006-05-04
We present a holographic dark-energy model in which the Newton constant G{sub N} scales in such a way as to render the vacuum energy density a true constant. Nevertheless, the model acts as a dynamical dark-energy model since the scaling of G{sub N} goes at the expense of deviation of concentration of dark-matter particles from its canonical form and/or of promotion of their mass to a time-dependent quantity, thereby making the effective equation of state (EOS) variable and different from -1 at the present epoch. Thus the model has a potential to naturally underpin Dirac's suggestion for explaining the large-number hypothesis, which demands a dynamical G{sub N} along with the creation of matter in the universe. We show that with the aid of observational bounds on the variation of the gravitational coupling, the effective-field theory IR cutoff can be strongly restricted, being always closer to the future event horizon than to the Hubble distance. As for the observational side, the effective EOS restricted by observation can be made arbitrary close to -1, and therefore the present model can be considered as a 'minimal' dynamical dark-energy scenario. In addition, for nonzero but small curvature (vertical bar {omega}{sub k0} vertical bar -bar 0.003), the model easily accommodates a transition across the phantom line for redshifts z-bar 0.2, as mildly favored by the data. A thermodynamic aspect of the scenario is also discussed.
Analysis of the chemical equilibrium of combustion at constant volume
Directory of Open Access Journals (Sweden)
Marius BREBENEL
2014-04-01
Full Text Available Determining the composition of a mixture of combustion gases at a given temperature is based on chemical equilibrium, when the equilibrium constants are calculated on the assumption of constant pressure and temperature. In this paper, an analysis of changes occurring when combustion takes place at constant volume is presented, deriving a specific formula of the equilibrium constant. The simple reaction of carbon combustion in pure oxygen in both cases (constant pressure and constant volume is next considered as example of application, observing the changes occurring in the composition of the combustion gases depending on temperature.
on the correctness of load loss factor correctness of load loss factor ...
African Journals Online (AJOL)
eobe
JACOBS ENGINEERING INC/BRUNEL UNIVERSITY LONDON,UNITED KINGDOM ... distribution network involves estimating the active power (MW) losses .... Distribution Network Control Centre, if available, in calculating the LLF. This will ensure a better evaluation of the technical losses in any distribution network. 5.
Protonation constants of hydroxybenzenes in hydrochloric acid
Directory of Open Access Journals (Sweden)
S. B. TOSIC
1999-09-01
Full Text Available The absorption spectra of monohydroxybenzene (Fen, 1,3-dihydroxybenzene (Rez, 1,4-dihydroxybenzene (Hi, 1,2,3-trihydroxybenzene (Pg and 1,3,5-trihydroxybenzene (Fg in aqueous solutions of hydrochloric acid with different values of the Hammett acidity function(H0 have two absorption bands in the region between 190-220 nm and 260-290 nm. This behavior is similar in another mineral acids (H2SO4, H3PO4, HClO4. The absorbance decreases with increasing of acidity (with decreasing of H0 values because of O-protonation. The absorption maxima shift to longer wavelengths, and the graphic dependence of the absorption of the second band as a function of H0 gives characteristic S-curves. These curves show the different effect of the acid on the form the protonation of the investigated hydroxybenzenes. The potonation constants of the hydroxybenzenes were calculated: pKFen=-1.95; pKRez=-2.40; pKHi= -1.93; pKPg=-2.95; pKFg=-1.83.
Accurate lineshape spectroscopy and the Boltzmann constant.
Truong, G-W; Anstie, J D; May, E F; Stace, T M; Luiten, A N
2015-10-14
Spectroscopy has an illustrious history delivering serendipitous discoveries and providing a stringent testbed for new physical predictions, including applications from trace materials detection, to understanding the atmospheres of stars and planets, and even constraining cosmological models. Reaching fundamental-noise limits permits optimal extraction of spectroscopic information from an absorption measurement. Here, we demonstrate a quantum-limited spectrometer that delivers high-precision measurements of the absorption lineshape. These measurements yield a very accurate measurement of the excited-state (6P1/2) hyperfine splitting in Cs, and reveals a breakdown in the well-known Voigt spectral profile. We develop a theoretical model that accounts for this breakdown, explaining the observations to within the shot-noise limit. Our model enables us to infer the thermal velocity dispersion of the Cs vapour with an uncertainty of 35 p.p.m. within an hour. This allows us to determine a value for Boltzmann's constant with a precision of 6 p.p.m., and an uncertainty of 71 p.p.m.
Magnetically modified biocells in constant magnetic field
Energy Technology Data Exchange (ETDEWEB)
Abramov, E.G.; Panina, L.K. [Saint Petersburg State University, St. Petersburg (Russian Federation); Kolikov, V.A., E-mail: kolikov1@yandex.ru [Institute for Electrophysics and Electric Power of the RAS, St. Petersburg (Russian Federation); Bogomolova, E.V. [Botanical Institute of the RAS after V.L.Komarov, St. Petersburg (Russian Federation); Snetov, V.N. [Institute for Electrophysics and Electric Power of the RAS, St. Petersburg (Russian Federation); Cherepkova, I.A. [Saint Petersburg State Institute of Technology, St. Petersburg (Russian Federation); Kiselev, A.A. [Institute for Electrophysics and Electric Power of the RAS, St. Petersburg (Russian Federation)
2017-02-01
Paper addresses the inverse problem in determining the area, where the external constant magnetic field captures the biological cells modified by the magnetic nanoparticles. Zero velocity isolines, in area where the modified cells are captured by the magnetic field were determined by numerical method for two locations of the magnet. The problem was solved taking into account the gravitational field, magnetic induction, density of medium, concentration and size of cells, and size and magnetization of nanoparticles attached to the cell. Increase in the number of the nanoparticles attached to the cell and decrease in the cell’ size, enlarges the area, where the modified cells are captured and concentrated by the magnet. Solution is confirmed by the visible pattern formation of the modified cells Saccharomyces cerevisiae. - Highlights: • The inverse problem was solved for finding zero velocity isolines of magnetically modified biological cells. • Solution of the inverse problem depends on the size of cells and the number of nanoparticles attached to the single cell. • The experimental data are in agreement with theoretical solution.
Asymptotically simple spacetimes and mass loss due to gravitational waves
Saw, Vee-Liem
The cosmological constant Λ used to be a freedom in Einstein’s theory of general relativity (GR), where one had a proclivity to set it to zero purely for convenience. The signs of Λ or Λ being zero would describe universes with different properties. For instance, the conformal structure of spacetime directly depends on Λ: null infinity ℐ is a spacelike, null, or timelike hypersurface, if Λ > 0, Λ = 0, or Λ 0 in Einstein’s theory of GR. A quantity that depends on the conformal structure of spacetime, especially on the nature of ℐ, is the Bondi mass which in turn dictates the mass loss of an isolated gravitating system due to energy carried away by gravitational waves. This problem of extending the Bondi mass to a universe with Λ > 0 has spawned intense research activity over the past several years. Some aspects include a closer inspection on the conformal properties, working with linearization, attempts using a Hamiltonian formulation based on “linearized” asymptotic symmetries, as well as obtaining the general asymptotic solutions of de Sitter-like spacetimes. We consolidate on the progress thus far from the various approaches that have been undertaken, as well as discuss the current open problems and possible directions in this area.
Constant-intensity waves and their modulation instability in non-Hermitian potentials
Makris, K. G.; Musslimani, Z. H.; Christodoulides, D. N.; Rotter, S.
2015-07-01
In all of the diverse areas of science where waves play an important role, one of the most fundamental solutions of the corresponding wave equation is a stationary wave with constant intensity. The most familiar example is that of a plane wave propagating in free space. In the presence of any Hermitian potential, a wave's constant intensity is, however, immediately destroyed due to scattering. Here we show that this fundamental restriction is conveniently lifted when working with non-Hermitian potentials. In particular, we present a whole class of waves that have constant intensity in the presence of linear as well as of nonlinear inhomogeneous media with gain and loss. These solutions allow us to study the fundamental phenomenon of modulation instability in an inhomogeneous environment. Our results pose a new challenge for the experiments on non-Hermitian scattering that have recently been put forward.
Estimation of the Plant Time Constant of Current-Controlled Voltage Source Converters
DEFF Research Database (Denmark)
Vidal, Ana; Yepes, Alejandro G.; Malvar, Jano
2014-01-01
Precise knowledge of the plant time constant is essential to perform a thorough analysis of the current control loop in voltage source converters (VSCs). As the loop behavior can be significantly influenced by the VSC working conditions, the effects associated to converter losses should be included...... of the VSC interface filter measured at rated conditions. This paper extends that method so that both parameters of the plant time constant (resistance and inductance) are estimated. Such enhancement is achieved through the evaluation of the closed-loop transient responses of both axes of the synchronous...... in the model, through an equivalent series resistance. In a recent work, an algorithm to identify this parameter was developed, considering the inductance value as known and practically constant. Nevertheless, the plant inductance can also present important uncertainties with respect to the inductance...
Methodology of measurement of thermal neutron time decay constant in Canberra 35+ MCA system
Energy Technology Data Exchange (ETDEWEB)
Drozdowicz, K.; Gabanska, B.; Igielski, A.; Krynicka, E.; Woznicka, U. [Institute of Nuclear Physics, Cracow (Poland)
1993-12-31
A method of the thermal neutron time decay constant measurement in small bounded media is presented. A 14 MeV pulsed neutron generator is the neutron source. The system of recording of a die-away curve of thermal neutrons consists of a {sup 3}He detector and of a multichannel time analyzer based on analyzer Canberra 35+ with multi scaler module MCS 7880 (microsecond range). Optimum parameters for the measuring system are considered. Experimental verification of a dead time of the instrumentation system is made and a count-loss correction is incorporated into the data treatment. An attention is paid to evaluate with a high accuracy the fundamental mode decay constant of the registered decaying curve. A new procedure of the determination of the decay constant by a multiple recording of the die-away curve is presented and results of test measurements are shown. (author). 11 refs, 12 figs, 4 tabs.
Baker, Stephen D.
1996-01-01
A commonly suggested method for determining the Newtonian constant of universal gravitation (G) is to observe the motion of two bodies of known mass moving about each other in an orbiting laboratory. In low Earth orbit (LEO), bodies constructed of even the densest material available experience a gravitational attraction that is several times smaller than the 'tidal' forces (due to their proximity to the Earth), which tend to pull them apart. While the tidal forces do not preclude stable orbits of the two objects about each other, they and the Coriolis force (in the rotating laboratory) dominate the motion, and the gravitational attraction of the two bodies may be considered a weak (but significant) contribution to the motion. As a result, compared to an experiment that would be performed in a laboratory far from the Earth, greater accuracy of measuring the motion of the two bodies may be required for a given accuracy in the determination of G. We find that the accuracy with which positions must be determined is not much different in an experiment in LEO than in one performed far from the Earth, but that rotational periods must be determined more accurately. Using a curvature matrix analysis, we also find that a value of G may be extracted (with some loss in accuracy, but probably some practical gain) from an analysis of the time dependence of the distance between the bodies rather than of a full specification (distance and direction) of their relative positions. A measurement of the gravitational constant to one part in 10(exp 4) continues to be thinkable, but one part in 10(exp 5) will be very difficult.
Quantum deformation of quantum cosmology: A framework to discuss the cosmological constant problem
Jalalzadeh, S.; Capistrano, A. J. S.; Moniz, P. V.
2017-12-01
We endorse the context that the cosmological constant problem is a quantum cosmology issue. Therefore, in this paper we investigate the q-deformed Wheeler-DeWitt equation of a spatially closed homogeneous and isotropic Universe in the presence of a conformally coupled scalar field. Specifically, the quantum deformed Universe is a quantized minisuperspace model constructed from quantum Heisenberg-Weyl Uq(h4) and Uq(su(1 , 1)) groups. These intrinsic mathematical features allow to establish that (i) the scale factor, the scalar field and corresponding momenta are quantized and (ii) the phase space has a non-equidistance lattice structure. On the other hand, such quantum group structure provides us a new framework to discuss the cosmological constant problem. Subsequently, we show that a ultraviolet cutoff can be obtained at 10-3 eV, i.e., at a scale much larger than the expected Planck scale. In addition, an infrared cutoff, at the size of the observed Universe, emerges from within such quantum deformation of Universe. In other words, the spectrum of the scale factor is upper bounded. Moreover, we show that the emerged cosmological horizon is a quantum sphere Sq2 or, alternatively, a fuzzy sphere SF2 which explicitly exhibits features of the holographic principle. The corresponding number of fundamental cells equals the dimension of the Hilbert space and hence, the cosmological constant can be presented as a consequence of the quantum deformation of the FLRW minisuperspace.
Harfmann, Katya L; Bechtel, Mark A
2015-03-01
Hair loss is a common cause of morbidity for many women. As a key member of the woman's health care team, the obstetrician/gynecologist may be the first person to evaluate the complaint of hair loss. Common types of nonscarring hair loss, including female pattern hair loss and telogen effluvium, may be diagnosed and managed by the obstetrician/gynecologist. A systematic approach to diagnosis and management of these common forms of hair loss is presented.
Ashok Murthy, V.; Krishna, Kirtan
2011-01-01
To study hearing loss in healthy pregnant women. Tertiary care hospital. Prospective study. We screened fifty healthy, non-complicated pregnant women (study group) in the third trimester for hearing loss who had no previous history for the same. Fifty healthy, non-pregnant women (control group) were also screened for hearing loss with a normal pure tone audiogram (PTA) for evidence of hearing loss. Thirteen women in the study group had evidence of hearing loss, in the form of absence of disto...
Constant light exposure impairs immune tolerance development in mice.
Mizutani, Hiromi; Tamagawa-Mineoka, Risa; Minami, Yoichi; Yagita, Kazuhiro; Katoh, Norito
2017-04-01
An intrinsic daily physiological rhythm called circadian rhythm has been indicated to affect the immune system and its related diseases. Immune tolerance development is closely associated with the onset of immunological disorders. However, the effect of circadian rhythm in the mechanisms of immune tolerance development has not yet been fully understood. The purpose of this study was to investigate the effects of circadian rhythm disruption on the development of immune tolerance by the perturbation of light environment, using a mouse model of neonatally induced cutaneous tolerance. Mice were kept under constant light (LL) or light-dark (LD) conditions, and hapten was applied at 2days after birth. Six weeks later, hapten was reapplied to abdominal skin, followed by hapten application to ear skin 5days later. The ear-swelling responses and cell infiltration into inflamed skin significantly increased in LL mice compared with those in LD mice. Interestingly, the percentage and the number of Foxp3(+)-regulatory T cells notably decreased in inflamed skin and draining lymph nodes of LL mice compared with that in LD mice. Loss-of-function mutation of a key circadian gene, Bmal1, also exacerbated the ear-swelling responses and cell infiltration into inflamed skin in mice. These results suggest that circadian rhythm may be implicated in immune tolerance development in allergic inflammation. Copyright © 2016 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.
Colossal dielectric constant of NaNbO3 doped BaTiO3 ceramics
Directory of Open Access Journals (Sweden)
Cao Wan Q.
2016-06-01
Full Text Available BaTiO3 ceramics doped with 0.40 mol% NaNbO3 were prepared using a traditional approach by sintering at temperature of 1250 °C to 1290 °C. The prepared ceramics was characterized by very good dielectric properties, such as high dielectric constant (1.5 × 105, low dielectric loss (0.1, and good dielectric temperature stability in the −40 °C to 100 °C range for the sample sintered below 1270 °C. The dielectric characteristics obtained with XPS confirmed that Ti4+ ions remain in the state without any change. The huge increase in dielectric constant in NaNbO3 doped BaTiO3 samples occurs when large amount of Ba2+ ions are excited to a high energy bound state of Ba2+ − e or Ba+ to create electron hopping conduction. For samples with the content of NaNbO3 higher than 0.40 mol%, or sintering temperature higher than 1280 °C, compensation effect is dominated by cation vacancies with sharply decreasing dielectric constant and increased dielectric loss. The polaron effect is used to explain the relevant mechanism of giant dielectric constant appearing in the ferroelectric phase.
Constant Proportion Portfolio Insurance Strategy in Southeast European Markets
National Research Council Canada - National Science Library
Elma Agić-Šabeta
2016-01-01
.... A special attention is given to modelling non-risky assets of the portfolio. Monte Carlo simulations are used to test the buy-and-hold, the constant-mix, and the constant proportion portfolio insurance (CPPI...
Wheatstone bridge fed from a bilateral constant current source.
Velayudhan, C; Oommen, D
1980-03-01
A simple inexpensive scheme of an electronic amplifier for Wheatstone bridge application is presented. The bridge is excited from a bilateral constant current square wave source. The advantage of constant current drive is presented.
The specific gamma-ray constant and exposure rate constant of 182Ta.
Glasgow, G P; Dillman, L T
1982-01-01
Reported values of the specific gamma-ray constant gamma for 182Ta range from the original value of 6.1 to 7.692 R cm2h-1mCi-1, recommended in NCRP Report No. 41. The original calculation of gamma was based on inadequate nuclear spectroscopy and decay scheme data. The higher value of gamma occurs because of a computational error in the relative intensity of the 1.2575-MeV gamma ray. Using nuclear spectroscopy data from the most recent Evaluated Nuclear Data File (ENSDF), gamma is calculated to be 6.71 +/- 0.06 R cm2h-1mCi-1 and the exposure rate constant gamma gamma is 6.87 +/- 0.06 R cm2h-1mCi-1. These new calculations are presented and previously reported values of gamma and gamma gamma are reviewed.
2002-01-01
This report contains translations of three papers published in the Nuclear Constants journal (Voprosy Atomnoj Nauki I Teknniki, seriya: Yadernye Konstanty (YK), vypusk 2, 2001). They are marked as 'Translated from Russian'. Three original YK papers published in English and one sent by the are included with corrections of misprints and small format changes. As a result the report contains seven of nine papers presented in YK, 2 (2001).
Amyloid plaque formation precedes dendritic spine loss.
Bittner, Tobias; Burgold, Steffen; Dorostkar, Mario M; Fuhrmann, Martin; Wegenast-Braun, Bettina M; Schmidt, Boris; Kretzschmar, Hans; Herms, Jochen
2012-12-01
Amyloid-beta plaque deposition represents a major neuropathological hallmark of Alzheimer's disease. While numerous studies have described dendritic spine loss in proximity to plaques, much less is known about the kinetics of these processes. In particular, the question as to whether synapse loss precedes or follows plaque formation remains unanswered. To address this question, and to learn more about the underlying kinetics, we simultaneously imaged amyloid plaque deposition and dendritic spine loss by applying two-photon in vivo microscopy through a cranial window in double transgenic APPPS1 mice. As a result, we first observed that the rate of dendritic spine loss in proximity to plaques is the same in both young and aged animals. However, plaque size only increased significantly in the young cohort, indicating that spine loss persists even many months after initial plaque appearance. Tracking the fate of individual spines revealed that net spine loss is caused by increased spine elimination, with the rate of spine formation remaining constant. Imaging of dendritic spines before and during plaque formation demonstrated that spine loss around plaques commences at least 4 weeks after initial plaque formation. In conclusion, spine loss occurs, shortly but with a significant time delay, after the birth of new plaques, and persists in the vicinity of amyloid plaques over many months. These findings hence give further hope to the possibility that there is a therapeutic window between initial amyloid plaque deposition and the onset of structural damage at spines.
CRISIS COMMUNICATION IN UNIVERSITIES
Directory of Open Access Journals (Sweden)
Canan MADRAN
2015-07-01
Full Text Available Abstract Institutions should implement effective crisis communication strategies to manage their reputations in crisis situations. Thus, the negative perceptions that may occur because of crisis can be reduced and eliminated by continuously informing stakeholders. Therefore, various researches are needed in the area of crisis communication management. The aim of the study is to determine the types of crises that often occur in universities and evaluate the crisis communication efforts in higher education institutions. Crises and crisis communication efforts were evaluated within the framework of media reflections in this study. Content analysis was applied in the classification of crises and responses provided for crises. As a result, the types of crises in Turkish universities were determined as campus safety, actions, protests, loss of confidential information, loss of financial opportunities, loss of key managers and personnel, staff problems, increase of accidents, slander and gossip, unnecessary explanations, rumors, damage to organization and employee reputation, terrorism, workplace violence, corruption, fire and epidemic. It is seen that universities don’t make any communicational effort regarding campus safety, staff problems, increase of accidents, corruption or fire.
Systematic harmonic power laws inter-relating multiple fundamental constants
Chakeres, Donald; Buckhanan, Wayne; Andrianarijaona, Vola
2017-01-01
Power laws and harmonic systems are ubiquitous in physics. We hypothesize that 2, π, the electron, Bohr radius, Rydberg constant, neutron, fine structure constant, Higgs boson, top quark, kaons, pions, muon, Tau, W, and Z when scaled in a common single unit are all inter-related by systematic harmonic powers laws. This implies that if the power law is known it is possible to derive a fundamental constant's scale in the absence of any direct experimental data of that constant. This is true for the case of the hydrogen constants. We created a power law search engine computer program that randomly generated possible positive or negative powers searching when the product of logical groups of constants equals 1, confirming they are physically valid. For 2, π, and the hydrogen constants the search engine found Planck's constant, Coulomb's energy law, and the kinetic energy law. The product of ratios defined by two constants each was the standard general format. The search engine found systematic resonant power laws based on partial harmonic fraction powers of the neutron for all of the constants with products near 1, within their known experimental precision, when utilized with appropriate hydrogen constants. We conclude that multiple fundamental constants are inter-related within a harmonic power law system.
Reliability concerns with logical constants in Xilinx FPGA designs
Energy Technology Data Exchange (ETDEWEB)
Quinn, Heather M [Los Alamos National Laboratory; Graham, Paul [Los Alamos National Laboratory; Morgan, Keith [Los Alamos National Laboratory; Ostler, Patrick [Los Alamos National Laboratory; Allen, Greg [JPL; Swift, Gary [XILINX; Tseng, Chen W [XILINX
2009-01-01
In Xilinx Field Programmable Gate Arrays logical constants, which ground unused inputs and provide constants for designs, are implemented in SEU-susceptible logic. In the past, these logical constants have been shown to cause the user circuit to output bad data and were not resetable through off-line rcconfiguration. In the more recent devices, logical constants are less problematic, though mitigation should still be considered for high reliability applications. In conclusion, we have presented a number of reliability concerns with logical constants in the Xilinx Virtex family. There are two main categories of logical constants: implicit and explicit logical constants. In all of the Virtex devices, the implicit logical constants are implemented using half latches, which in the most recent devices are several orders of magnitudes smaller than configuration bit cells. Explicit logical constants are implemented exclusively using constant LUTs in the Virtex-I and Virtex-II, and use a combination of constant LUTs and architectural posts to the ground plane in the Virtex-4. We have also presented mitigation methods and options for these devices. While SEUs in implicit and some types of explicit logical constants can cause data corrupt, the chance of failure from these components is now much smaller than it was in the Virtex-I device. Therefore, for many cases, mitigation might not be necessary, except under extremely high reliability situations.
Determination and stability constants of Manganese (II) amino acid ...
African Journals Online (AJOL)
Determination and stability constants of Manganese (II) amino acid complexes. HN Aliyu, J Na'aliya. Abstract. The stepwise and the overall stability constants of the complexes formed by manganese (II) ion and twelve (12) amino acids have been determined. The dissociation constants, pKa, of the amino acids determined ...
Determination of optical constants and nonlinear optical coefficients ...
Indian Academy of Sciences (India)
The optical properties of Violet 1-doped polyvinyl alcohol (PVA) have been investigated using Wemble and Didomenico (WD) method. The optical constants such as refractive index , the dispersion energy , the oscillation energy 0, the lattice dielectric constant ∞, light frequency dielectric constant 0 and the ratio of ...
Male broiler performance and nocturnal feeding under constant 8-h ...
African Journals Online (AJOL)
When these data were pooled with previously reported data for female broilers, growth and feed conversion efficiency post 21 d and through to depletion for constant 8-h and birds transferred from 8 to 16 h at 20 d were significantly superior to constant 16-h birds. Constant 8-h birds ate about half their feed during the dark ...
Beauty vector meson decay constants from QCD sum rules
Energy Technology Data Exchange (ETDEWEB)
Lucha, Wolfgang [Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); Melikhov, Dmitri [Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); D. V. Skobeltsyn Institute of Nuclear Physics, M. V. Lomonosov Moscow State University, 119991, Moscow (Russian Federation); Simula, Silvano [Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre, Via della Vasca Navale 84, I-00146, Roma (Italy)
2016-01-22
We present the outcomes of a very recent investigation of the decay constants of nonstrange and strange heavy-light beauty vector mesons, with special emphasis on the ratio of any such decay constant to the decay constant of the corresponding pseudoscalar meson, by means of Borel-transformed QCD sum rules. Our results suggest that both these ratios are below unity.
Stability constant of the trisglycinto metal complexes | Na'aliya ...
African Journals Online (AJOL)
The stability constants of iron, manganese, cobalt, and nickel complexes of glycine have been determined in aqueous solution by potentiometric titration with standard sodium hydroxide solution. The values of the stepwise stability constants were obtained by ORIGIN '50' program. The overall stability constants of the ...
Nuclear magnetic resonance J coupling constant polarizabilities of hydrogen peroxide
DEFF Research Database (Denmark)
Kjær, Hanna; Nielsen, Monia R.; Pagola, Gabriel I.
2012-01-01
In this paper we present the so far most extended investigation of the calculation of the coupling constant polarizability of a molecule. The components of the coupling constant polarizability are derivatives of the NMR indirect nuclear spin-spin coupling constant with respect to an external elec...
Runway incursions – clear and constant danger
Directory of Open Access Journals (Sweden)
Maria MRAZOVA
2014-09-01
Full Text Available Runway safety plays an important role in aviation industry. This paper deals with runway safety – runway incursion as a serious safety concern. Focusing attention on this issue is necessary due to many collisions with a significant loss of life and many aircraft damages. The first paragraph deals with general information about runway incursions with concentration on statistical overview of runway incidents. The second paragraph describes possible ways of mitigating processes that will lead to decreasing rate of incidents mainly at airports with confusing runway/taxiway orientation, such as Zurich Airport. It also emphasises importance of hot spots identification and subsequently their location at each airport. The last part of this paper deals with practical illustration of runway safety at mentioned Zurich Airport due to its confusing emplacement of runways and taxiways. Not less important are also positions of Action Plans and Action Teams at the point of solving problems related to runway incidents. Briefly, runway safety is an ongoing effort and we are committed to finding ways of making a safe system even safer. In addition to current runway safety initiatives, the following efforts will further the progress of increasing runway safety over the next several years.
Search for Varying Constants of Nature from Astronomical Observation of Molecules
Ubachs, Wim
2018-02-01
The status of searches for possible variation in the constants of nature from astronomical observation of molecules is reviewed, focusing on the dimensionless constant representing the proton-electron mass ratio μ =mp/me. The optical detection of H2 and CO molecules with large ground-based telescopes (as the ESO-VLT and the Keck telescopes), as well as the detection of H2 with the Cosmic Origins Spectrograph aboard the Hubble Space Telescope is discussed in the context of varying constants, and in connection to different theoretical scenarios. Radio astronomy provides an alternative search strategy bearing the advantage that molecules as NH3 (ammonia) and CH3OH (methanol) can be used, which are much more sensitive to a varying μ than diatomic molecules. Current constraints are |Δ μ /μ | Universe (both at 3σ statistical significance). Existing bottlenecks and prospects for future improvement with novel instrumentation are discussed.
a Note on the Effect of the Cosmological Constant on the Bending of Light
Hammad, Fayçal
2013-12-01
We take another look at the equations behind the description of light bending in a Universe with a cosmological constant. We show that even within the impact parameter entering into the photon's differential equation, and which is defined here with exclusive reference to the beam of light as it bends around the central mass, lies the contribution of the cosmological constant. The latter is shown to enter in a novel way into the equation. When the latter is solved our approach implies, beyond the first two orders in the mass-term and the lowest-order in the cosmological constant, a slightly different expression for the bending angle from what is previously found in the literature.
Irregular AC loss in a large SMES coil; Ogata SMES koiru no fukisoku koryu sonshitsu
Energy Technology Data Exchange (ETDEWEB)
Hamajima, T.; Yoshida, M.; Shimamura, T.; Harada, N.; Tsuda, M. [Yamaguchi Univ., Yamaguchi (Japan); Hanai, S. [Toshiba Corp., Tokyo (Japan); Hirano, N. [Chubu Electric Power Co., Inc., Aichi (Japan); Sato, T. [National Inst. for Fusion Science, Nagoya (Japan)
2000-05-29
From the results of a series of tests on SMES model coil, it was confirmed that, in AC loss of large SMES wound with large current capacity cable in conduit (CIC) conductor, there was regular AC loss estimated from the short sample test results of conductor and irregular AC loss observed in a coil condition. Irregular AC loss was estimated being caused by many loops with long time constant between several seconds and about 100 seconds composed inside conductor. The analysis results on loss of each elementary wire in cable showed that number of loops was about 20,000 and there was an existing possibility of many loops. An average value of time constant spectrum was about 18 seconds and is a little shorter than of an average time constant 30 seconds obtained from frequency analysis of AC loss. The maximum value was 150 seconds, and indicated an existing possibility of time constant of about 100 seconds obtained by the test. (NEDO)
Continuous-waveform constant-current isolated physiological stimulator
Holcomb, Mark R.; Devine, Jack M.; Harder, Rene; Sidorov, Veniamin Y.
2012-04-01
We have developed an isolated continuous-waveform constant-current physiological stimulator that is powered and controlled by universal serial bus (USB) interface. The stimulator is composed of a custom printed circuit board (PCB), 16-MHz MSP430F2618 microcontroller with two integrated 12-bit digital to analog converters (DAC0, DAC1), high-speed H-Bridge, voltage-controlled current source (VCCS), isolated USB communication and power circuitry, two isolated transistor-transistor logic (TTL) inputs, and a serial 16 × 2 character liquid crystal display. The stimulators are designed to produce current stimuli in the range of ±15 mA indefinitely using a 20V source and to be used in ex vivo cardiac experiments, but they are suitable for use in a wide variety of research or student experiments that require precision control of continuous waveforms or synchronization with external events. The device was designed with customization in mind and has features that allow it to be integrated into current and future experimental setups. Dual TTL inputs allow replacement by two or more traditional stimulators in common experimental configurations. The MSP430 software is written in C++ and compiled with IAR Embedded Workbench 5.20.2. A control program written in C++ runs on a Windows personal computer and has a graphical user interface that allows the user to control all aspects of the device.
Turbulent energy losses during orchard heating
Energy Technology Data Exchange (ETDEWEB)
Bland, W.L.
1979-01-01
Two rapid-response drag anemometers and low time constant thermocouples, all at 4 m above a heated orchard floor, sampled wind component in the vertical direction and temperature at 30 Hz. The turbulent heat flux calculated revealed not more than 10% of the heat lost from the orchard was via turbulent transort. The observations failed to support previous estimates that at least a third of the energy applied was lost through turbulent transport. Underestimation of heat loss due to mean flow and a newly revealed flux due to spatial variations in the mean flow may explain the unaccounted for loss.
Can the baryon number density and the cosmological constant be interrelated?
Minamizaki, Azusa; Sugamoto, Akio
2008-01-01
A toy model is proposed in which the cosmological constant and the baryon number density of the Universe are interrelated. The model combines the mechanism of Dimopoulos and Susskind [S. Dimopoulos, L. Susskind, Phys. Rev. D 18 (1978) 4500] in which the baryon number density of the Universe is generated by the time-dependence of the phase of a complex scalar field, i.e. its ‘angular momentum’ in the two-dimensional complex field space, with that of Yoshimura [M. Yoshimura, Phys. Lett. B 608 (2005) 183, hep-ph/0410183] in which the ‘centrifugal force’ due to the ‘angular momentum’ pushes the vacuum expectation value of the scalar field out of a negative potential minimum and provides a small but positive cosmological constant. Unfortunately, our model fails to relate the smallness of the two numbers directly, requiring a fine-tuning of the negative potential minimum.
Quantum adiabatic computation with a constant gap is not useful in one dimension
Energy Technology Data Exchange (ETDEWEB)
Hastings, Matthew [Los Alamos National Laboratory
2009-01-01
We show that it is possible to use a classical computer to efficiently simulate the adiabatic evolution of a quantum system in one dimension with a constant spectral gap, starting the adiabatic evolution from a known initial product state. The proof relies on a recently proven area law for such systems, implying the existence of a good matrix product representation of the ground state, combined with an appropriate algorithm to update the matrix product state as the Hamiltonian is changed. This implies that adiabatic evolution with such Hamiltonians is not useful for universal quantum computation. Therefore, adiabatic algorithms which are useful for universal quantum computation either require a spectral gap tending to zero or need to be implemented in more than one dimension (we leave open the question of the computational power of adiabatic simulation with a constant gap in more than one dimension).
DEFF Research Database (Denmark)
Álvarez-Asencio, R.; Thormann, Esben; Rutland, M.W.
2013-01-01
A technique has been developed for the calculation of torsional spring constants for AFM cantilevers based on the combination of the normal spring constant and plate/beam theory. It is easy to apply and allow the determination of torsional constants for stiff cantilevers where the thermal power...
Stability of viscous fluid in Bianchi type-VI model with cosmological constant
Sadeghi, J.; Amani, Ali R.; Tahmasbi, N.
2013-12-01
In this paper, we investigate Bianchi type-VI cosmological model for the universe filled with dark energy and viscous fluid in the presence of cosmological constant. Also, we show accelerating expansion of the universe by drawing volume scale, pressure and energy density versus cosmic time. In order to solve the Einstein's field equations, we assume the expansion scalar is proportional to a component of the shear tensor. Therefore, we obtain the directional scale factors and show the EOS parameter crosses over phantom divided-line.
Spherical collapse of a unified dark fluid with constant adiabatic sound speed
Xu, Lixin
2013-03-01
In this paper, we test the spherical collapse of a unified dark fluid (UDF) which has constant adiabatic sound speed. By choosing the different values of model parameters B s and α, we show the non-linear collapse for UDF and baryons which are considered for their formation of the large scale structure of our Universe. The analyzed results show that larger values of α and B s make the structure formation faster and earlier.
Spherical collapse of a unified dark fluid with constant adiabatic sound speed
Energy Technology Data Exchange (ETDEWEB)
Xu, Lixin [Dalian University of Technology, Institute of Theoretical Physics, School of Physics and Optoelectronic Technology, Dalian (China); Dalian University of Technology, College of Advanced Science and Technology, Dalian (China)
2013-03-15
In this paper, we test the spherical collapse of a unified dark fluid (UDF) which has constant adiabatic sound speed. By choosing the different values of model parameters B{sub s} and {alpha}, we show the non-linear collapse for UDF and baryons which are considered for their formation of the large scale structure of our Universe. The analyzed results show that larger values of {alpha} and B{sub s} make the structure formation faster and earlier. (orig.)
The Definition and Classification of Universes
Energy Technology Data Exchange (ETDEWEB)
Bjorken, J.
2004-10-12
We assume that the concept of a multiverse makes sense, and suggest a specific, standardized definition for member universes which are similar to our own. Central to this description is the definition of size, which is taken to be the asymptotic value, at large times, of the inverse Hubble constant. Thus the cosmological constant plays a central role in defining the properties of the subset of universes similar to our own. We then assume that vacuum parameters and coupling constants of the standard model are dependent upon the size of a universe, and propose a specific form for the dependence. Anthropic considerations then limit the size of habitable universes (as we understand that concept) to be within a factor two of our own. Implications of this picture for understanding the standard-model ''hierarchy problem'' are discussed, as are general issues of falsifiability and/or verifiability of these ideas.
... Category: Share: Yes No, Keep Private Telogen Effluvium Hair Loss Share | It is normal to lose up to ... months after the "shock". This sudden increase in hair loss, usually described as the hair coming out in ...
Injection losses and protection
Bartmann, W; Baudrenghien, P; Bracco, C; Dehning, B; Di Mauro, A; Drosdal, L; Emery, J; Goddard, B; Holzer, E B; Höfle, W; Kain, V; Meddahi, M; Radaelli, S; Shaposhnilova, E; Uythoven, J; Valuch, D; Wenninger, J; Zamantzas, C; Gianfelice-Wendt, E
2012-01-01
Injection losses are compared for 2010 and 2011 operation. Mitigation techniques which were put in place in 2010 to reduce losses at injection are described. Issues in 2011 operation, their potential improvements and the performance reach for 2012 are shown.
Hearing Loss and Osteogenesis Imperfecta Introduction Significant hearing loss has been reported in approximately 50% of people with osteogenesis imperfecta (OI) beginning any time from childhood into middle age. While not ...
... and how often you are exposed to loud music Headphone use Family history of hearing loss Jobs or activities that increase your chance of hearing loss from music are: Being a musician, sound crew member, or ...
DEFF Research Database (Denmark)
Egerup, Pia; Kolte, A M; Larsen, E C
2016-01-01
STUDY QUESTION: Is there a different prognostic impact for consecutive and non-consecutive early pregnancy losses in women with secondary recurrent pregnancy loss (RPL)? SUMMARY ANSWER: Only consecutive early pregnancy losses after the last birth have a statistically significant negative prognostic...... impact in women with secondary RPL. WHAT IS KNOWN ALREADY: The risk of a new pregnancy loss increases with the number of previous pregnancy losses in patients with RPL. Second trimester losses seem to exhibit a stronger negative impact than early losses. It is unknown whether the sequence of pregnancy...... losses plays a role for the prognosis in patients with a prior birth. STUDY DESIGN, SIZE, DURATION: This retrospective cohort study of pregnancy outcome in patients with unexplained secondary RPL included in three previously published, Danish double-blinded placebo-controlled trials of intravenous...
Massa, Enrico; Nicolaus, Arnold
2011-04-01
This issue of Metrologia collects papers about the results of an international research project aimed at the determination of the Avogadro constant, NA, by counting the atoms in a silicon crystal highly enriched with the isotope 28Si. Fifty years ago, Egidi [1] thought about realizing an atomic mass standard. In 1965, Bonse and Hart [2] operated the first x-ray interferometer, thus paving the way to the achievement of Egidi's dream, and soon Deslattes et al [3] completed the first counting of the atoms in a natural silicon crystal. The present project, outlined by Zosi [4] in 1983, began in 2004 by combining the experiences and capabilities of the BIPM, INRIM, IRMM, NIST, NPL, NMIA, NMIJ and PTB. The start signal, ratified by a memorandum of understanding, was a contract for the production of a silicon crystal highly enriched with 28Si. The enrichment process was undertaken by the Central Design Bureau of Machine Building in St Petersburg. Subsequently, a polycrystal was grown in the Institute of Chemistry of High-Purity Substances of the Russian Academy of Sciences in Nizhny Novgorod and a 28Si boule was grown and purified by the Leibniz-Institut für Kristallzüchtung in Berlin. Isotope enrichment made it possible to apply isotope dilution mass spectroscopy, to determine the Avogadro constant with unprecedented accuracy, and to fulfil Egidi's dream. To convey Egidi's 'fantasy' into practice, two 28Si kilogram prototypes shaped as quasi-perfect spheres were manufactured by the Australian Centre for Precision Optics; their isotopic composition, molar mass, mass, volume, density and lattice parameter were accurately determined and their surfaces were chemically and physically characterized at the atomic scale. The paper by Andreas et al reviews the work carried out; it collates all the findings and illustrates how Avogadro's constant was obtained. Impurity concentration and gradients in the enriched crystal were measured by infrared spectroscopy and taken into
Kapko, Vitaliy; Matyushov, Dmitry V; Angell, C Austen
2008-04-14
We report constant-volume and constant-pressure simulations of the thermodynamic and dynamic properties of the low-temperature liquid and crystalline phases of the modified Stillinger-Weber (SW) model. We have found an approximately linear temperature increase of the effective Gaussian width of the distribution of inherent structures. This effect comes from non-Gaussianity of the landscape and is consistent with the predictions of the Gaussian excitations model representing the thermodynamics of the configurational manifold as an ensemble of excitations, each carrying an excitation entropy. The SW model provides us with both the configurational and excess entropies, with the difference mostly attributed to vibrational anharmonicity. We therefore can address the distinction between the excess thermodynamic quantities, often used to interpret experiments, and configurational thermodynamics used to describe the dynamics in the Adam-Gibbs (AG) equation. However we are limited computationally to work at temperatures above the "crossover" temperature at which the breakdown in the Adam-Gibbs relation has been identified in laboratory studies. We find a new break in the slope of the constant pressure AG plot (in the same sense but at much higher temperature than with laboratory data) when the excess entropy is used in the AG equation. This break, which we associate with anharmonic vibrational effects, is not seen when the configurational entropy is used. The simulation diffusivity data are equally well fitted by the AG equation and by a new equation, derived within the Gaussian excitations model, that emphasizes enthalpy over entropy as the thermodynamic control variable for transport in viscous liquids. We show that the modified SW model has close links to the behavior observed for bulk metallic glasses, both in its diffusional and in its thermodynamic properties.
Canine hearing loss management.
Scheifele, Lesa; Clark, John Greer; Scheifele, Peter M
2012-11-01
Dog owners and handlers are naturally concerned when suspicion of hearing loss arises for their dogs. Questions frequently asked of the veterinarian center on warning signs of canine hearing loss and what can be done for the dog if hearing loss is confirmed. This article addresses warning signs of canine hearing loss, communication training and safety awareness issues, and the feasibility of hearing aid amplification for dogs. Copyright © 2012 Elsevier Inc. All rights reserved.
Effects of constant voltage and constant current stress in PCBM:P3HT solar cells
DEFF Research Database (Denmark)
Cester, Andrea; Rizzo, Aldo; Bazzega, A.
2015-01-01
The aimof this work is the investigation of forward and reverse bias stress effects, cell self-heating and annealing in roll coated organic solar cells with PCBM:P3HT active layer. In reverse bias stress cells show a constant degradation over time. In forward current stress cells alternate...... mechanisms: the decrease of the net generation rate (due to formation of exciton quenching centres or the reduction of exciton separation rate); the formation of small leaky paths between anode and cathode, which reduces the total current extracted from the cell. The stress-induced damage can be recovered...
Directory of Open Access Journals (Sweden)
Franklin Leopoldo e Silva
2001-05-01
Full Text Available O texto procura mostrar, por via de um comentário das posições de Adorno acerca das finalidades da educação, que a história da modernidade, vista como processo de constituição da hegemonia da razão instrumental, destituiu a educação de uma característica essencial, a formação da consciência para a liberdade, aspecto que no entanto se encontra implicado na relação entre experiência, verdade e felicidade, constitutiva do ideal humanista de sabedoria e de emancipação. O progresso civilizatório pode ser visto como a perda progressiva do ideal de formação, substituído pelos procedimentos de racionalização adaptativa do indivíduo às condições de alienação próprias do mundo administrado. Na impossibilidade de reinstauração das condições objetivas favoráveis à experiência educacional formadora, resta, na perspectiva de uma educação crítica, a tentativa de se opor à instrumentalização da subjetividade por via de um esforço de recuperação da negatividade como contraponto à adesão cega ao presente histórico.The text aims to show, based on a commentary of Adorno's points of view on the goals of education, that the history of modernity, seen as process for the constitution of the hegemony of instrumental reason, has removed an essencial feature from education: the formation of a consciousness for freedom, an aspect that is involved in the relationship between experience, truth and happiness, which constitute the humanist ideal of knowledge and emancipation. Civilizing progress can be seen as a progressive loss of the ideal of formation, substituted by the procedures of adaptive rationalization of the individual to the alienating conditions that are peculiar to the managed world. In the event of an impossibility to reinstall the favourable conditions to the cultivating education experience, we are left, from a critical education perspective, with an attempt to oppose the instrumentalization of subjectivity
Transition after Traumatic Loss
Kuban, Caelan
2011-01-01
Children experience grief when they suffer the loss of a close relationship. When that loss also traumatizes children, they experience additional emotional reactions. It is important that adults educate themselves and others who deal with children about typical, healthy grief reactions. Following a non-violent loss, the initial reactions of…
Fact Sheet Medici a ne n s d Bone Loss Some types of medicines can cause bone loss, making your bones weak, if used for a long time. Use over a short time ... old bone and replaces it with new bone. Bone loss occurs when old bone breaks down faster than ...
Obesity Epidemic: Pharmaceutical Weight Loss.
Curry, Stephanie A
2017-03-01
Obesity is a chronic disease universally defined as an excess of adipose tissue resulting in body mass index (BMI) > 30.0 kg/m2. Over the past few years, the concept of prevention has gained increased awareness, thus leading to the development of additional pharmaceutical options for the treatment of obesity since 2012. Treating obesity revolves around an individualized, multi-disciplinary approach with additional focus on a healthy and supportive lifestyle to maintain the weight loss. [Full article available at http://rimed.org/rimedicaljournal-2017-03.asp].
Two-dimensional quantum dilaton gravity and the quantized cosmological constant
Zonetti, Simone
2012-09-01
The cosmological constant problem is one of the long-standing issues of modern physics. While we can measure the value of the cosmological constant with great accuracy, we are not able to calculate it in a coherent theoretical framework. On the contrary the theoretical predictions in Quantum Field Theory are radically different from observations. This disagreement is a hint of the difficult conciliation of Quantum Mechanics and General Relativity in a theory of Quantum Gravity. Current approaches to the cosmological constant problem, in particular, do not account for the quantum nature of the gravitational interaction and rely on perturbative calculations. In this thesis we address the issue in the simplified framework of two-dimensional dilaton-Maxwell gravity, coupled to scalar matter fields. In this setting we are able to quantize our model non-perturbatively in Dirac's approach to constrained systems. We determine that the realization of the classical symmetries at the quantum level provides a mechanism that fixes the value of the cosmological constant once a specific quantum state of the Universe is selected. Furthermore Quantum Gravity introduces opposite contributions to the cosmological constant, admitting a range of values compatible with current observations.
Exact Initial Data for Black Hole Universes with a Cosmological Constant
Durk, Jessie
2016-01-01
We construct exact initial data for closed cosmological models filled with regularly arranged black holes in the presence of $\\Lambda$. The intrinsic geometry of the 3-dimensional space described by this data is a sum of simple closed-form expressions, while the extrinsic curvature is just proportional to $\\Lambda$. We determine the mass of each of the black holes in this space by performing a limiting procedure around the location of each of the black holes, and then compare the result to an appropriate slice through the Schwarzschild-de Sitter spacetime. The consequences of the inhomogeneity of this model for the large-scale expansion of space are then found by comparing the lengths of curves in the cosmological region to similar curves in a suitably chosen Friedmann-Lemaitre-Robertson-Walker (FLRW) solution. Finally, we locate the positions of the apparent horizons of the black holes, and determine the extremal values of their mass, for every possible regular arrangement of masses. We find that as the numb...
Specific gamma-ray constant and exposure rate constant of 192Ir.
Glasgow, G P; Dillman, L T
1979-01-01
Calculated values of the 192Ir specific gamma-ray constant, Gamma range from the low value of 3.948 R cm2h-1mCi-1 recommended in NCRP No. 41 to a high of 4.89 R cm2h-1mCi-1. Measured values of Gamma range only from 4.85 to 5.0 Rcm2h-1mCi-1. Discrepancies in reported calculated values exist because the isotope decay scheme and other nuclear spectroscopy data pertinent to these calculations were not well known. Using the 28 gamma rays and relative intensities from the most recent Evaluated Nuclear Structure Data File (ENSDF), Gamma is calculated to be 4.62 +/- 0.05 Rcm2h-1mCi-1 and the exposure rate constant Gamma delta is 4.69 +/- 0.05 Rcm2h-1mCi-1. These new calculations are presented and previously reported values of Gamma and Gamma delta are reviewed.
Sankatsing Nava, Tibisay; Russo, Pedro
2015-08-01
Universe Awareness (UNAWE) is an educational programme coordinated by Leiden University that uses the beauty and grandeur of the Universe to encourage young children, particularly those from an underprivileged background, to have an interest in science and technology and foster their sense of global citizenship from the earliest age.UNAWE's twofold vision uses our Universe to inspire and motivate very young children: the excitement of the Universe provides an exciting introduction to science and technology, while the vastness and beauty of the Universe helps broaden the mind and stimulate a sense of global citizenship and tolerance. UNAWE's goals are accomplished through four main activities: the coordination of a global network of more than 1000 astronomers, teachers and educators from more than 60 countries, development of educational resources, teacher training activities and evaluation of educational activities.Between 2011 and 2013, EU-UNAWE, the European branch of UNAWE, was funded by the European Commission to implement a project in 5 EU countries and South Africa. This project has been concluded successfully. Since then, the global project Universe Awareness has continued to grow with an expanding international network, new educational resources and teacher trainings and a planned International Workshop in collaboration with ESA in October 2015, among other activities.
Plum, M.A.
2016-01-01
Beam loss is a critical issue in high-intensity accelerators, and much effort is expended during both the design and operation phases to minimize the loss and to keep it to manageable levels. As new accelerators become ever more powerful, beam loss becomes even more critical. Linacs for H- ion beams, such as the one at the Oak Ridge Spallation Neutron Source, have many more loss mechanisms compared to H+ (proton) linacs, such as the one being designed for the European Spallation Neutron Source. Interesting H- beam loss mechanisms include residual gas stripping, H+ capture and acceleration, field stripping, black-body radiation and the recently discovered intra-beam stripping mechanism. Beam halo formation, and ion source or RF turn on/off transients, are examples of beam loss mechanisms that are common for both H+ and H- accelerators. Machine protection systems play an important role in limiting the beam loss.
Osborne, Richard
2012-01-01
Where did the Universe come from? The single biggest and most difficult question that there is. From early religions through Greek Philosophy and Western Science man has attempted to discover the meaning of our place in the Universe. In the last twenty years these debates have been cast in a new light by amazing discoveries, big bang theory and ideas about new sub-atomic layers. The nature of Time and Space are truly up for grabs. With a witty and accessible style Osborne leads us on a historical and informative journey through the philosophies of the universe including the importance
Directory of Open Access Journals (Sweden)
Jorge Andrés Rubio-Romero
2010-07-01
immediately after vaginal delivery. Material and methods. A diagnostic accuracy study was carried out in a cohort of pregnant women who had a vaginal delivery at an university hospital. It was approved by the ethics and investigation committees of participating institutions. A complex gold standard combining clinical and laboratory signs was defined: need of therapeutic maneuvers for treatment of post partum hemorrhage, drop of 10% or more of previous hematocrit or need of transfusion. Results. Incidence of SPPH was 10,7% of the 168 patients included. Median volume of estimated blood loss was 375 mL while median real observed blood volume was 475 mL. For the diagnosis of SPPH, estimated blood loss greater than 500 mL had a sensitivity and specificity of 77,8 y 73,3% respectively. For estimated blood loss greater than 800 mL, sensitivity and specificity were 44,4 and 94%. This cut point is the one that better classifies puerperal women requiring initial treatment for diagnose an abnormal hemorrhage of the post partum. Conclusions. Visual estimation of blood loss during delivery is a poorly sensitive and specific diagnostic test for the diagnosis of SPPH due to underestimation of the real magnitude of the blood loss occurred. Key words: validity of tests, reproducibility of results, sensitivity and specificity, postpartum hemorrhage. Rubio-Romero JA, Guevara-Cruz OA, Gaitán- Duarte H. Validity of visual estimation of blood loss as diagnostic tool in severe post partum hemorrhage in an university hospital. Bogotá. 2007. Rev.Fac.Med. 2010; 58: 173-184.
Quintessential Nature of the Fine-Structure Constant
Sherbon, Michael
2015-01-01
7 pages; International audience; An introduction is given to the geometry and harmonics of the Golden Apex in the Great Pyramid, with the metaphysical and mathematical determination of the fine-structure constant of electromagnetic interactions. Newton's gravitational constant is also presented in harmonic form and other fundamental physical constants are then found related to the quintessential geometry of the Golden Apex in the Great Pyramid.
A Constant Envelope OFDM Implementation on GNU Radio
2015-02-02
Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/5524--15-9575 A Constant Envelope OFDM Implementation on GNU Radio February 2, 2015...NUMBER OF PAGES 17. LIMITATION OF ABSTRACT A Constant Envelope OFDM Implementation on GNU Radio Andrew Robertson, Amos Ajo, Sastry Kompella, Joe...time for non-linear amplification. These requirements are uniquely served by constant envelope OFDM . We describe the use-cases, theory, and
US Agency for International Development — USAID University is USAID's learning management system. Features include 1) Access online courses 2) Register for instructor-led courses 3)Access your student...
Process and Microstructure to Achieve Ultra-high Dielectric Constant in Ceramic-Polymer Composites
Zhang, Lin; Shan, Xiaobing; Bass, Patrick; Tong, Yang; Rolin, Terry D.; Hill, Curtis W.; Brewer, Jeffrey C.; Tucker, Dennis S.; Cheng, Z.-Y.
2016-01-01
Influences of process conditions on microstructure and dielectric properties of ceramic-polymer composites are systematically studied using CaCu3Ti4O12 (CCTO) as filler and P(VDF-TrFE) 55/45 mol.% copolymer as the matrix by combining solution-cast and hot-pressing processes. It is found that the dielectric constant of the composites can be significantly enhanced–up to about 10 times – by using proper processing conditions. The dielectric constant of the composites can reach more than 1,000 over a wide temperature range with a low loss (tan δ ~ 10−1). It is concluded that besides the dense structure of composites, the uniform distribution of the CCTO particles in the matrix plays a key role on the dielectric enhancement. Due to the influence of the CCTO on the microstructure of the polymer matrix, the composites exhibit a weaker temperature dependence of the dielectric constant than the polymer matrix. Based on the results, it is also found that the loss of the composites at low temperatures, including room temperature, is determined by the real dielectric relaxation processes including the relaxation process induced by the mixing. PMID:27767184
The 400-Hertz constant-speed electrical generation systems
Mcclung, R.
1982-01-01
Materials illustrating a presentation on 400 Hz constant speed generation systems are presented. The system features are outlined, components and functioning described, and display graphics illustrated.
An Einstein-Cartan Fine Structure Constant Definition
Directory of Open Access Journals (Sweden)
Stone R. A. Jr.
2010-01-01
Full Text Available The fine structure constant definition given in Stone R.A. Jr. Progress in Physics, 2010, v.1, 11-13 is compared to an Einstein-Cartan fine structure constant definition. It is shown that the Einstein-Cartan definition produces the correct pure theory value, just not the measure value. To produce the measured value, the pure theory Einstein-Cartan fine structure constant requires only the new variables and spin coupling of the fine structure constant definition in [1].
Negative Dielectric Constant Material Based on Ion Conducting Materials
Gordon, Keith L. (Inventor); Kang, Jin Ho (Inventor); Park, Cheol (Inventor); Lillehei, Peter T. (Inventor); Harrison, Joycelyn S. (Inventor)
2017-01-01
Metamaterials or artificial negative index materials (NIMs) have generated great attention due to their unique and exotic electromagnetic properties. One exemplary negative dielectric constant material, which is an essential key for creating the NIMs, was developed by doping ions into a polymer, a protonated poly (benzimidazole) (PBI). The doped PBI showed a negative dielectric constant at megahertz (MHz) frequencies due to its reduced plasma frequency and an induction effect. The magnitude of the negative dielectric constant and the resonance frequency were tunable by doping concentration. The highly doped PBI showed larger absolute magnitude of negative dielectric constant at just above its resonance frequency than the less doped PBI.
Scalar-tensor theory of gravitation with negative coupling constant
Smalley, L. L.; Eby, P. B.
1976-01-01
The possibility of a Brans-Dicke scalar-tensor gravitation theory with a negative coupling constant is considered. The admissibility of a negative-coupling theory is investigated, and a simplified cosmological solution is obtained which allows a negative derivative of the gravitation constant. It is concluded that a Brans-Dicke theory with a negative coupling constant can be a viable alternative to general relativity and that a large negative value for the coupling constant seems to bring the original scalar-tensor theory into close agreement with perihelion-precession results in view of recent observations of small solar oblateness.
Konrad, Andreas; Budini, Francesco; Tilp, Markus
2017-08-01
Static stretching induces acute structural changes of the muscle-tendon unit (MTU) that are related to the intensity or duration of stretching. It has been reported that stretching with a constant torque (CT) leads to greater joint range of motion changes than stretching with a constant angle (CA). Whether or not this difference is due to different structural changes of the MTUs of the lower leg and ankle plantar flexors is not known. Therefore, the purpose of this study was to compare the acute effects of single CA and CT stretching on various muscle and tendon mechanical properties. Seventeen young, healthy volunteers were tested on two separate days using either CT or CA stretching (4 × 30 s each). Before and after stretching, dorsiflexion range of motion (RoM), passive resistive torque (PRT), and maximum voluntary contraction (MVC) were measured with a dynamometer. Ultrasonography of the medial gastrocnemius (GM) muscle-tendon junction (MTJ) displacement allowed us to determine the length changes in the tendon and muscle, respectively, and hence to calculate their stiffness. Maximum dorsiflexion increased while PRT, muscle-tendon stiffness, and muscle stiffness decreased following both CA and CT stretching. There was a greater increase in RoM following CT stretching compared to CA stretching. Moreover, the decline in PRT was greater during CT stretching compared to CA stretching. As expected, several functional adaptations (RoM, PRT) were different between CT and CA stretching due to the higher intensity of CT stretching. However, no structural differences in the adaptations to the stretching modalities could be detected. We suggest that the different functional adaptations between CA and CT stretching are the consequence of different adaptations in the perception of stretch and pain.
Hu, Ji-Ying; Li, Zhao-Hui; Sun, Yang; Li, Qi-Hu
2016-12-01
Shear-mode piezoelectric materials have been widely used to shunt the damping of vibrations where utilizing surface or interface shear stresses. The thick-shear mode (TSM) elastic constant and the mechanical loss factor can change correspondingly when piezoelectric materials are shunted to different electrical circuits. This phenomenon makes it possible to control the performance of a shear-mode piezoelectric damping system through designing the shunt circuit. However, due to the difficulties in directly measuring the TSM elastic constant and the mechanical loss factor of piezoelectric materials, the relationships between those parameters and the shunt circuits have rarely been investigated. In this paper, a coupling TSM electro-mechanical resonant system is proposed to indirectly measure the variations of the TSM elastic constant and the mechanical loss factor of piezoelectric materials. The main idea is to transform the variations of the TSM elastic constant and the mechanical loss factor into the changes of the easily observed resonant frequency and electrical quality factor of the coupling electro-mechanical resonator. Based on this model, the formular relationships are set up theoretically with Mason equivalent circuit method and they are validated with finite element (FE) analyses. Finally, a prototype of the coupling electro-mechanical resonator is fabricated with two shear-mode PZT5A plates to investigate the TSM elastic constants and the mechanical loss factors of different circuit-shunted cases of the piezoelectric plate. Both the resonant frequency shifts and the bandwidth changes observed in experiments are in good consistence with the theoretical and FE analyses under the same shunt conditions. The proposed coupling resonator and the obtained relationships are validated with but not limited to PZT5A. Project supported by the National Defense Foundation of China (Grant No. 9149A12050414JW02180).
Directory of Open Access Journals (Sweden)
Mavromatos Nick E.
2016-01-01
Full Text Available On the occasion of a century from the proposal of General relativity by Einstein, I attempt to tackle some open issues in modern cosmology, via a toy but non-trivial model. Specifically, I would like to link together: (i the smallness of the cosmological constant today, (ii the evolution of the universe from an inflationary era after the bigbang till now, and (iii local supersymmetry in the gravitational sector (supergravity with a broken spectrum at early eras, by making use of the concept of the “running vacuum” in the context of a simple toy model of four-dimensional N = 1 supergravity. The model is characterised by dynamically broken local supersymmetry, induced by the formation of gravitino condensates in the early universe. As I will argue, there is a Starobinsky-type inflationary era characterising the broken supersymmetry phase in this model, which is compatible with the current cosmological data, provided a given constraint is satisfied among some tree-level parameters of the model and the renormalised cosmological constant of the de Sitter background used in the analysis. Applying the “running vacuum” concept, then, to the effective field theory at the exit of inflation, makes a smooth connection (in cosmic time with the radiation dominance epoch and subsequently with the current era of the Universe, characterised by a small (but dominant cosmological-constant contribution to the cosmic energy density. In this approach, the smallness of the cosmological constant today is attributed to the failure (due to quantum gravity non-perturbative effects of the aforementioned constraint.
Directory of Open Access Journals (Sweden)
Mariola Sliwinska-Kowalska
2012-01-01
Full Text Available Noise-induced hearing loss (NIHL still remains a problem in developed countries, despite reduced occupational noise exposure, strict standards for hearing protection and extensive public health awareness campaigns. Therefore NIHL continues to be the focus of noise research activities. This paper summarizes progress achieved recently in our knowledge of NIHL. It includes papers published between the years 2008-2011 (in English, which were identified by a literature search of accessible medical and other relevant databases. A substantial part of this research has been concerned with the risk of NIHL in the entertainment sector, particularly in professional, orchestral musicians. There are also constant concerns regarding noise exposure and hearing risk in "hard to control" occupations, such as farming and construction work. Although occupational noise has decreased since the early 1980s, the number of young people subject to social noise exposure has tripled. If the exposure limits from the Noise at Work Regulations are applied, discotheque music, rock concerts, as well as music from personal music players are associated with the risk of hearing loss in teenagers and young adults. Several recent research studies have increased the understanding of the pathomechanisms of acoustic trauma, the genetics of NIHL, as well as possible dietary and pharmacologic otoprotection in acoustic trauma. The results of these studies are very promising and offer grounds to expect that targeted therapies might help prevent the loss of sensory hair cells and protect the hearing of noise-exposed individuals. These studies emphasize the need to launch an improved noise exposure policy for hearing protection along with developing more efficient norms of NIHL risk assessment.
Sliwinska-Kowalska, Mariola; Davis, Adrian
2012-01-01
Noise-induced hearing loss (NIHL) still remains a problem in developed countries, despite reduced occupational noise exposure, strict standards for hearing protection and extensive public health awareness campaigns. Therefore NIHL continues to be the focus of noise research activities. This paper summarizes progress achieved recently in our knowledge of NIHL. It includes papers published between the years 2008-2011 (in English), which were identified by a literature search of accessible medical and other relevant databases. A substantial part of this research has been concerned with the risk of NIHL in the entertainment sector, particularly in professional, orchestral musicians. There are also constant concerns regarding noise exposure and hearing risk in "hard to control" occupations, such as farming and construction work. Although occupational noise has decreased since the early 1980s, the number of young people subject to social noise exposure has tripled. If the exposure limits from the Noise at Work Regulations are applied, discotheque music, rock concerts, as well as music from personal music players are associated with the risk of hearing loss in teenagers and young adults. Several recent research studies have increased the understanding of the pathomechanisms of acoustic trauma, the genetics of NIHL, as well as possible dietary and pharmacologic otoprotection in acoustic trauma. The results of these studies are very promising and offer grounds to expect that targeted therapies might help prevent the loss of sensory hair cells and protect the hearing of noise-exposed individuals. These studies emphasize the need to launch an improved noise exposure policy for hearing protection along with developing more efficient norms of NIHL risk assessment.
Patel, Mansi; Harrison, Shannon; Sinclair, Rodney
2013-01-01
Hair loss is a common complaint, both in men and women, and use of prescription medications is widespread. When there is a temporal association between the onset of hair loss and commencement of a medication, the medication is commonly thought to have caused the hair loss. However, hair loss and in particular telogen effluvium may occur in response to a number of triggers including fever, hemorrhage, severe illness, stress, and childbirth, and a thorough exclusion of these potential confounders is necessary before the hair loss can be blamed on the medication. Certain medications are known to cause hair loss by a variety of mechanisms including anagen arrest, telogen effluvium, or accentuation of androgenetic alopecia by androgens. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.
Schmidt, Klaus; Schnaus, Anja
2016-01-01
This handbook presents the basic aspects of actuarial loss reserving. Besides the traditional methods, it also includes a description of more recent ones and a discussion of certain problems occurring in actuarial practice, like inflation, scarce data, large claims, slow loss development, the use of market statistics, the need for simulation techniques and the task of calculating best estimates and ranges of future losses. In property and casualty insurance the provisions for payment obligations from losses that have occurred but have not yet been settled usually constitute the largest item on the liabilities side of an insurer's balance sheet. For this reason, the determination and evaluation of these loss reserves is of considerable economic importance for every property and casualty insurer. Actuarial students, academics as well as practicing actuaries will benefit from this overview of the most important actuarial methods of loss reserving by developing an understanding of the underlying stochastic models...
Lueck, Christian J
2010-12-01
Visual loss is not uncommon and many patients end up seeing neurologists because of it. There is a long list of possible causes but in most patients visual loss is associated with visual field loss. This means that for practical purposes the differential diagnosis can usually be narrowed down to a manageable shortlist by consideration of where in the visual pathway the lesion is likely to be, along with the time course of the visual loss. This article provides a practical approach to the diagnosis and appropriate investigation of such patients, dividing them into four groups: those in whom vision is lost transiently, acutely, subacutely (i.e., days to weeks) and over a longer time frame (months to years). In addition, there is a discussion of those patients in whom visual loss is not obviously accompanied by any visual field loss.
Emergent Universe with particle production
Gangopadhyay, Sunandan; Mukherjee, S
2014-01-01
The possibility of an emergent universe solution to Einstein's field equations allowing for an irreversible creation of matter at the expense of the gravitational field is shown. With the universe being chosen as spatially flat FRW spacetime together with equation of state proposed in [17], the solution exists when the ratio of the phenomenological matter creation rate to the number density times the Hubble parameter is a number $\\beta$ of the order of unity and independent of time. The thermodynamic behaviour is also determined for this solution. Interestingly, we also find that an emergent universe scenario is present with usual equation of state in cosmology when the matter creation rate is chosen to be a constant. More general class of emergent universe solutions are also discussed.
A Physics Model for Weight Loss by Dieting
2012-09-01
body, weight change, diet, energy loss. Resumen El peso promedio de una persona está determinado por el equilibrio entre su ingesta de calorías...through by 2x to get 2 1 1dx X dt T x X , (2) where the two constants a and b have been re-expressed in terms of two new... constants /X a b and 22 /T a b . Their physical significance is that 2W X is the person’s equilibrium weight and T is a time constant characterizing
Reference-dependent preferences and loss aversion
Directory of Open Access Journals (Sweden)
Einat Neuman
2008-02-01
Full Text Available This study employs a Discrete Choice Experiment (DCE in the health-care sector to test the loss aversion theory that is derived from reference-dependent preferences: The absolute subjective value of a deviation from a reference point is generally greater when the deviation represents a loss than when the same-sized change is perceived as a gain. As far as is known, this paper is the first to use a DCE to test the loss aversion theory. A DCE is a highly suitable tool for such testing because it estimates the marginal valuations of attributes, based onextit{ deviations from a reference point} (a constant scenario. Moreover, loss aversion can be examined for extit{each attribute separately}. Another advantage of a DCE is that is can be applied toextit{ non-traded goods with non-tangible attributes}. A health-care event is used for empirical illustration: The loss aversion theory is tested within the context of preference structures for maternity-ward attributes, estimated using data gathered from 3850 observations made by a sample of 542 women who had recently given birth. Seven hypotheses are presented and tested. Overall, significant support for behavioral loss aversion theories was found. %JEL codes: D01, D12, I19
Directory of Open Access Journals (Sweden)
Marquet P.
2014-10-01
Full Text Available This paper investigates the G ̈odel’s exact solution of the Einstein equations which describes a stationary homogeneous cosmological Universe inducing closed timelike curves CTCs. This model is generally dismissed because it exhibits a rotational sym- metry and it requires a non zero cosmological constant in contradiction with the current astronomical observations. If the cosmological term is assumed to be slightly variable, we show that this metric can be compatible with the Hubble expansion, which makes the G ̈odel model a viable representation of our Universe.
University Internationalization and University Autonomy
DEFF Research Database (Denmark)
Turcan, Romeo V.; Gulieva, Valeria
2016-01-01
are determined by the structure and exercise of university autonomy settings at home and in the host countries, and that the process itself cannot be successfully achieved and maintained without changes in the autonomy settings. The key question the authors ask is to what degree universities, in embracing new......, dissimilar, and sometimes conflicting dimensions of the financial, legal, organisational, staffing, and academic autonomy of the host country, are compromising key aspects of their own autonomy and core mission?...
Carr, Bernard
2009-08-01
Part I. Overviews: 1. Introduction and overview Bernard Carr; 2. Living in the multiverse Steven Weinberg; 3. Enlightenment, knowledge, ignorance, temptation Frank Wilczek; Part II. Cosmology and Astrophysics: 4. Cosmology and the multiverse Martin J. Rees; 5. The anthropic principle revisited Bernard Carr; 6. Cosmology from the top down Stephen Hawking; 7. The multiverse hierarchy Max Tegmark; 8. The inflationary universe Andrei Linde; 9. A model of anthropic reasoning: the dark to ordinary matter ratio Frank Wilczek; 10. Anthropic predictions: the case of the cosmological constant Alexander Vilenkin; 11. The definition and classification of universes James D. Bjorken; 12. M/string theory and anthropic reasoning Renata Kallosh; 13. The anthropic principle, dark energy and the LHC Savas Dimopoulos and Scott Thomas; Part III. Particle Physics and Quantum Theory: 14. Quarks, electrons and atoms in closely related universes Craig J. Hogan; 15. The fine-tuning problems of particle physics and anthropic mechanisms John F. Donoghue; 16. The anthropic landscape of string theory Leonard Susskind; 17. Cosmology and the many worlds interpretation of quantum mechanics Viatcheslav Mukhanov; 18. Anthropic reasoning and quantum cosmology James B. Hartle; 19. Micro-anthropic principle for quantum theory Brandon Carter; Part IV. More General Philosophical Issues: 20. Scientific alternatives to the anthropic principle Lee Smolin; 21. Making predictions in a multiverse: conundrums, dangers, coincidences Anthony Aguirre; 22. Multiverses: description, uniqueness and testing George Ellis; 23. Predictions and tests of multiverse theories Don N. Page; 24. Observation selection theory and cosmological fine-tuning Nick Bostrom; 25. Are anthropic arguments, involving multiverses and beyond, legitimate? William R. Stoeger; 26. The multiverse hypothesis: a theistic perspective Robin Collins; 27. Living in a simulated universe John D. Barrow; 28. Universes galore: where will it all end? Paul
A five-dimensional model of varying fine structure constant
Indian Academy of Sciences (India)
A five-dimensional model of varying fine structure constant. J P MBELEK. Service d'Astrophysique, C.E. Saclay, F-91191 Gif-sur-Yvette Cedex, France. Abstract. The cosmological variation of the fine structure constant « is explored from an effective theory, under the form of an improved version of the 5D Kaluza-Klein theory.
Avogadro constant measurements using enriched 28Si monocrystals
Fujii, K.; Massa, E.; Bettin, H.; Kuramoto, N.; Mana, G.
2018-02-01
Since 2011, the International Avogadro Coordination has been measuring the Avogadro constant by counting the atoms in enriched 28Si monocrystals. This communication provides guidance on how the recently published results should be used to update the values of the Avogadro constant measured so far.
A Priori Probability Distribution of the Cosmological Constant
Weinberg, Steven
2000-01-01
In calculations of the probability distribution for the cosmological constant, it has been previously assumed that the a priori probability distribution is essentially constant in the very narrow range that is anthropically allowed. This assumption has recently been challenged. Here we identify large classes of theories in which this assumption is justified.
Dielectric Constants of Irradiated and Carbonated Polymers | Okeke ...
African Journals Online (AJOL)
Using the LC resonance circuit, changes in dielectric constants of irradiated and carbonated polymers as a function of carbon concentration are investigated. Both low and high density polymers are used. Results predict a quadratic increase in the dielectric constant of specimen as the percentage concentration of carbon is ...
Surfaces of Constant Curvature in the Pseudo-Galilean Space
Directory of Open Access Journals (Sweden)
Željka Milin Šipuš
2012-01-01
constant curvature, so-called the Tchebyshev coordinates, and show that the angle between parametric curves satisfies the Klein-Gordon partial differential equation. We determine the Tchebyshev coordinates for surfaces of revolution and construct a surface with constant curvature from a particular solution of the Klein-Gordon equation.
Determination of stepwise stabilty constants and Gibb's free energy ...
African Journals Online (AJOL)
The overall stability constants of manganese (II), iron (II), cobalt (II), nickel (II), copper (II), and zinc (II) complexes with proline were determined by potentiometric titration of sodium prolinate with the corresponding salt of the divalent metal in aqueous media. The values of the constants (Logâ) were found to be 19.45, 19.23, ...
Using Constant Time Delay to Teach Braille Word Recognition
Hooper, Jonathan; Ivy, Sarah; Hatton, Deborah
2014-01-01
Introduction: Constant time delay has been identified as an evidence-based practice to teach print sight words and picture recognition (Browder, Ahlbrim-Delzell, Spooner, Mims, & Baker, 2009). For the study presented here, we tested the effectiveness of constant time delay to teach new braille words. Methods: A single-subject multiple baseline…
An Introduction to Collision Theory Rate Constants via Distribution Functions.
McAlduff, E. J.
1980-01-01
Described is an introduction to the collision theory by arriving at the many degrees of freedom rote constant and showing that the (-Ea/RT) is a special case and corresponds to activation in 2 squared terms on the line of center rate constant, which is found through the use of distributed functions. (Author/DS)
Lattice constant measurement from electron backscatter diffraction patterns
DEFF Research Database (Denmark)
Saowadee, Nath; Agersted, Karsten; Bowen, Jacob R.
2017-01-01
Kikuchi bands in election backscattered diffraction patterns (EBSP) contain information about lattice constants of crystallographic samples that can be extracted via the Bragg equation. An advantage of lattice constant measurement from EBSPs over diffraction (XRD) is the ability to perform local ...
Measuring Boltzmann's Constant with Carbon Dioxide
Ivanov, Dragia; Nikolov, Stefan
2013-01-01
In this paper we present two experiments to measure Boltzmann's constant--one of the fundamental constants of modern-day physics, which lies at the base of statistical mechanics and thermodynamics. The experiments use very basic theory, simple equipment and cheap and safe materials yet provide very precise results. They are very easy and…
Constant mean curvature surfaces via integrable dynamical system
Konopelchenko, B G
1995-01-01
It is shown that the equation which describes constant mean curvature surface via the generalized Weierstrass-Enneper inducing has Hamiltonian form. Its simplest finite-dimensional reduction has two degrees of freedom, integrable and its trajectories correspond to well-known Delaunay and do Carmo-Dajzcer surfaces (i.e., helicoidal constant mean curvature surfaces).
Teraji, T.; Arakaki, T.
2011-12-01
Use of artificial sweeteners in drinks and food has been rapidly increasing because of their non-calorie nature. In Japan, aspartame, acesulfame K and sucralose are among the most widely used artificial sweeteners. Because the artificial sweeteners are not metabolized in human bodies, they are directly excreted into the environment without chemical transformations. We initiated a study to better understand the fate of artificial sweeteners in the marine environment. In particular, we focused on the fate of aspartame by determining its bimolecular rate constants with hydroxyl radicals at various pH and temperature conditions and reaction by-products. The hydroxyl radical (OH), the most potent reactive oxygen species, reacts with various compounds and determines the environmental oxidation capacity and the life-time of many compounds. The steady-state OH concentration and the reaction rate constants between the compound and OH are used to estimate the life-time of the compound. In this study, we determine the bimolecular rate constants between aspartame and OH at various pH and temperature conditions using a competition kinetics technique. We use hydrogen peroxide as a photochemical source of OH. Bimolecular rate constant we obtained so far was (2.6±1.2)×109 M-1 s-1 at pH = 3.0. Little effect was seen by changing the temperatures between 15 and 40 °C. Activation energy (Ea) was calculated to be -1.0 kJ mol-1 at pH = 3.0, which could be regarded as zero. We will report reaction rate constants at different pHs and reaction by-products which will be analyzed by GC-MS. We will further discuss the fate of aspartame in the coastal environment.
Hearing Loss in Children: Types of Hearing Loss
... Hearing Loss Homepage Facts Noise-Induced Hearing Loss Genetics of Hearing Loss Screening & Diagnosis Types of Hearing Loss About Sound Treatment & Intervention Services Learning Language Bacterial Meningitis Studies Data & Statistics EHDI Annual Data 2015 ...
Mohamadou, Youssoufa; In Oh, Tong; Wi, Hun; Sohal, Harsh; Farooq, Adnan; Woo, Eung Je; McEwan, Alistair Lee
2012-10-01
Current sources are widely used in bio-impedance spectroscopy (BIS) measurement systems to maximize current injection for increased signal to noise while keeping within medical safety specifications. High-performance current sources based on the Howland current pump with optimized impedance converters are able to minimize stray capacitance of the cables and setup. This approach is limited at high frequencies primarily due to the deteriorated output impedance of the constant current source when situated in a real measurement system. For this reason, voltage sources have been suggested, but they require a current sensing resistor, and the SNR reduces at low impedance loads due to the lower current required to maintain constant voltage. In this paper, we compare the performance of a current source-based BIS and a voltage source-based BIS, which use common components. The current source BIS is based on a Howland current pump and generalized impedance converters to maintain a high output impedance of more than 1 MΩ at 2 MHz. The voltage source BIS is based on voltage division between an internal current sensing resistor (Rs) and an external sample. To maintain high SNR, Rs is varied so that the source voltage is divided more or less equally. In order to calibrate the systems, we measured the transfer function of the BIS systems with several known resistor and capacitor loads. From this we may estimate the resistance and capacitance of biological tissues using the least-squares method to minimize error between the measured transimpedance excluding the system transfer function and that from an impedance model. When tested on realistic loads including discrete resistors and capacitors, and saline and agar phantoms, the voltage source-based BIS system had a wider bandwidth of 10 Hz to 2.2 MHz with less than 1% deviation from the expected spectra compared to more than 10% with the current source. The voltage source also showed an SNR of at least 60 dB up to 2.2 MHz in
Energy Technology Data Exchange (ETDEWEB)
Turner, M.S. (Fermi National Accelerator Lab., Batavia, IL (USA) Chicago Univ., IL (USA). Enrico Fermi Inst.)
1990-10-01
Inflation provides very strong motivation for a flat Universe, Harrison-Zel'dovich (constant-curvature) perturbations, and cold dark matter. However, there are a number of cosmological observations that conflict with the predictions of the simplest such model -- one with zero cosmological constant. They include the age of the Universe, dynamical determinations of {Omega}, galaxy-number counts, and the apparent abundance of large-scale structure in the Universe. While the discrepancies are not yet serious enough to rule out the simplest and most well motivated'' model, the current data point to a best-fit model'' with the following parameters: {Omega}{sub B} {approx equal} 0.03, {Omega}{sub CDM} {approx equal} 0.17, {Omega}{sub {Lambda}} {approx equal} 0.8, and H{sub 0} {approx equal} 70 km sec{sup {minus}1} Mpc{sup {minus}1}, which improves significantly the concordance with observations. While there is no good reason to expect such a value for the cosmological constant, there is no physical principle that would rule out such. 42 refs.
Temperature dependence of the dielectric constant of acrylic dielectric elastomer
Energy Technology Data Exchange (ETDEWEB)
Sheng, Junjie; Chen, Hualing; Li, Bo; Chang, Longfei [Xi' an Jiaotong University, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi' an (China); Xi' an Jiaotong University, School of Mechanical Engineering, Xi' an (China)
2013-02-15
The dielectric constant is an essential electrical parameter to the achievable voltage-induced deformation of the dielectric elastomer. This paper primarily focuses on the temperature dependence of the dielectric constant (within the range of 173 K to 373 K) for the most widely used acrylic dielectric elastomer (VHB 4910). First the dielectric constant was investigated experimentally with the broadband dielectric spectrometer (BDS). Results showed that the dielectric constant first increased with temperature up to a peak value and then dropped to a relative small value. Then by analyzing the fitted curves, the Cole-Cole dispersion equation was found better to characterize the rising process before the peak values than the Debye dispersion equation, while the decrease process afterward can be well described by the simple Debye model. Finally, a mathematical model of dielectric constant of VHB 4910 was obtained from the fitted results which can be used to further probe the electromechanical stability of the dielectric elastomers. (orig.)
Temperature dependence of the dielectric constant of acrylic dielectric elastomer
Sheng, Junjie; Chen, Hualing; Li, Bo; Chang, Longfei
2013-02-01
The dielectric constant is an essential electrical parameter to the achievable voltage-induced deformation of the dielectric elastomer. This paper primarily focuses on the temperature dependence of the dielectric constant (within the range of 173 K to 373 K) for the most widely used acrylic dielectric elastomer (VHB 4910). First the dielectric constant was investigated experimentally with the broadband dielectric spectrometer (BDS). Results showed that the dielectric constant first increased with temperature up to a peak value and then dropped to a relative small value. Then by analyzing the fitted curves, the Cole-Cole dispersion equation was found better to characterize the rising process before the peak values than the Debye dispersion equation, while the decrease process afterward can be well described by the simple Debye model. Finally, a mathematical model of dielectric constant of VHB 4910 was obtained from the fitted results which can be used to further probe the electromechanical stability of the dielectric elastomers.
Fundamental Constants in Physics and their Time Dependence
CERN. Geneva
2008-01-01
In the Standard Model of Particle Physics we are dealing with 28 fundamental constants. In the experiments these constants can be measured, but theoretically they are not understood. I will discuss these constants, which are mostly mass parameters. Astrophysical measurements indicate that the finestructure constant is not a real constant, but depends on time. Grand unification then implies also a time variation of the QCD scale. Thus the masses of the atomic nuclei and the magnetic moments of the nuclei will depend on time. I proposed an experiment, which is currently done by Prof. Haensch in Munich and his group. The first results indicate a time dependence of the QCD scale. I will discuss the theoretical implications.
Academic Training Lectures | The Cosmological Constant Problem | 12-13 November
2015-01-01
Please note that the next series of Academic Training Lectures will take place on the 12 and 13 November. The lectures will be given by Antonio Padilla (University of Nottingham, UK). The Cosmological Constant Problem (1/2) on Thursday, 12 November from 11:00 a.m. to 12:30 p.m. https://indico.cern.ch/event/453187/ The Cosmological Constant Problem (2/2) on Friday, 13 November from 11:00 a.m. to 12:30 p.m. https://indico.cern.ch/event/453188/ at CERN, Council Chamber (503-1-001) Description: I will review the cosmological constant problem as a serious challenge to our notion of naturalness in Physics. Weinberg’s no go theorem is worked through in detail. I review a number of proposals possibly including Linde's universe multiplication, Coleman's wormholes, the fat graviton, and SLED, to name a few. Large distance modifications of gravity are also discussed, with causality considerations pointi...
The Future of Higher Education in Zimbabwe: A Constantly Moving ...
African Journals Online (AJOL)
Higher education in Zimbabwe began in the 1950s with the establishment of the University of Zimbabwe (then known as the University College of Rhodesia and Nyasaland) being the first institution to offer university education. Since then there has been a rapid growth of universities, particularly after in 1990. What can be ...
AC loss calculation of central solenoid model coil
Energy Technology Data Exchange (ETDEWEB)
Gilanyi, A. [Technical University of Budapest, Budapest (Hungary); Akiba, Masato; Okumura, Yoshikazu; Sugimoto, Makoto; Takahashi, Yoshikazu; Tsuji, Hiroshi
1999-03-01
The AC loss of Central Solenoid Model Coil of ITER is calculated in order to be able to determine the allowable excitation current shape in time with respect to the available cooling capacity at liquid helium temperature. In Part A the theory is summarized essential to present calculation. This covers a semianalytical integral formulation to calculate the magnetic field distribution in the cross-section of a coil and also 2D and 3D differential formulations for eddy current calculation of jackets and structural steel components, respectively. In Part B the conditions and results of calculation are described in detail. Losses are calculated separately in different components. Also the different types of losses are separated, and only one of the followings is considered in the same time; eddy current loss, ferromagnetic hysteresis loss, superconducting hysteresis loss, coupling loss. The followings are concluded. The coupling loss was found to be the largest 83% of the total AC loss supposing 50 msec characteristic time constant. Also significant amount of heat is generated in structural steels, cooling is required for stainless steel structural components. The loss of joints is not large, however concentrated, therefore joints should receive attention. Specially Lap-type joints are critical components. The eddy current and coupling power losses can be significantly decreased by increasing the ramp-up time since they are proportional to the square of flux change rate, while superconducting and ferromagnetic hysteresis power losses decrease linearly with decreasing flux change rate. Joule losses are produced in joints even after the energizing process of the magnet, when it is driven by a constant excitation current. This propose us to keep the time of full power operation short. (J.P.N.)
Loss muinasjuturaamatust / Agu Veetamm
Veetamm, Agu, 1953-
2004-01-01
Ballindaloch on üks väheseid Shoti losse, kus omanikud aastaringselt elavad. 450 aastat on loss kuulunud Macpherson-Grantide suguvõsale. Praegu on lossi omanikuks Clare Nancy Macpherson-Grant Russell, kelle kujundatud on kiviktaimla ja rosaarium. Lossi ajaloost, omanikest, ümberehitustest, ringkäigust lossis, pargist. 14 ill
Experimental circulation loss study
Lund, Sigurd
2013-01-01
Circulation losses could occur during any operation that involves pumping into a well. As of today, it is recognized as one of the most costly drilling problems. In some situation it might be hard to stop, and usually takes precious rig time to deal with the problem. In order to mitigate the risk of circulation loss solid pa...
Grief following homicidal loss
van Denderen, Mariëtte
2017-01-01
People confronted with homicidal loss have to cope with separation distress, related to their loss, and traumatic distress, associated with the circumstances surrounding the death. These reactions are related to complicated grief and posttraumatic stress symptoms. Based on a questionnaire study
Hearing Loss and Cytomegalovirus.
Strauss, Melvin
1997-01-01
Cytomegalovirus is the most common cause of congenital virally induced hearing loss. Maternal infection is most often asymptomatic as is the infection in the newborn. Hearing loss occurs in both clinically apparent infection and in the asymptomatic infection. Current methods of detection, treatment, and prevention and research efforts are…
Weight loss surgery helps people with extreme obesity to lose weight. It may be an option if you cannot lose weight through diet and exercise or have serious health problems caused by obesity. There are different types of weight loss surgery. They often limit the amount of food ...
Fact Sheet Proven Weight Loss Methods What can weight loss do for you? Losing weight can improve your health in a number of ways. ... you feel better. There are proven ways to lose weight. You can find what works for you. Research ...
S.D. Lindenbergh (Siewert); P.M. Kippersluis (Peter)
2009-01-01
textabstractNon pecuniary losses can be characterized as losses that are suffered by damaging goods or interests which have in themselves no economic price or value on a financial market. Examples are damage to goods with a primarily sentimental value, such as an album of wedding photos, pain and
Calculation of individual isotope equilibrium constants for geochemical reactions
Thorstenson, D.C.; Parkhurst, D.L.
2004-01-01
Theory is derived from the work of Urey (Urey H. C. [1947] The thermodynamic properties of isotopic substances. J. Chem. Soc. 562-581) to calculate equilibrium constants commonly used in geochemical equilibrium and reaction-transport models for reactions of individual isotopic species. Urey showed that equilibrium constants of isotope exchange reactions for molecules that contain two or more atoms of the same element in equivalent positions are related to isotope fractionation factors by ?? = (Kex)1/n, where n is the number of atoms exchanged. This relation is extended to include species containing multiple isotopes, for example 13C16O18O and 1H2H18O. The equilibrium constants of the isotope exchange reactions can be expressed as ratios of individual isotope equilibrium constants for geochemical reactions. Knowledge of the equilibrium constant for the dominant isotopic species can then be used to calculate the individual isotope equilibrium constants. Individual isotope equilibrium constants are calculated for the reaction CO2g = CO2aq for all species that can be formed from 12C, 13C, 16O, and 18O; for the reaction between 12C18 O2aq and 1H218Ol; and among the various 1H, 2H, 16O, and 18O species of H2O. This is a subset of a larger number of equilibrium constants calculated elsewhere (Thorstenson D. C. and Parkhurst D. L. [2002] Calculation of individual isotope equilibrium constants for implementation in geochemical models. Water-Resources Investigation Report 02-4172. U.S. Geological Survey). Activity coefficients, activity-concentration conventions for the isotopic variants of H2O in the solvent 1H216Ol, and salt effects on isotope fractionation have been included in the derivations. The effects of nonideality are small because of the chemical similarity of different isotopic species of the same molecule or ion. The temperature dependence of the individual isotope equilibrium constants can be calculated from the temperature dependence of the fractionation
Hesse, G
2016-06-01
Hearing loss is one of the most dominant handicaps in modern societies, which additionally very often is not realized or not admitted. About one quarter of the general population suffers from inner ear hearing loss and is therefore restricted in communicational skills. Demographic factors like increasing age play an important role as well as environmental influences and an increasing sound and noise exposure especially in leisure activities. Thus borders between a "classical" presbyacusis - if it ever existed - and envirionmentally induced hearing loss disappear. Today restrictions in hearing ability develop earlier in age but at the same time they are detected and diagnosed earlier. This paper can eventually enlighten the wide field of inner ear hearing loss only fragmentarily; therefore mainly new research, findings and developments are reviewed. The first part discusses new aspects of diagnostics of inner ear hearing loss and different etiologies. © Georg Thieme Verlag KG Stuttgart · New York.
... Hearing Loss Homepage Facts Noise-Induced Hearing Loss Genetics of Hearing Loss Screening & Diagnosis Types of Hearing Loss About Sound Treatment & Intervention Services Learning Language Bacterial Meningitis Studies Data & Statistics EHDI Annual Data 2015 ...
Thrift, Nigel
2016-01-01
This paper examines the future of Western higher education. Situated midway between an analysis and a polemic, it concerns itself with how we might begin to actively design the universities of the future. That will require a productionist account of higher education which is so far sadly lacking. But there are signs that such an account might be…
Methodology for extracting local constants from petroleum cracking flows
Chang, Shen-Lin; Lottes, Steven A.; Zhou, Chenn Q.
2000-01-01
A methodology provides for the extraction of local chemical kinetic model constants for use in a reacting flow computational fluid dynamics (CFD) computer code with chemical kinetic computations to optimize the operating conditions or design of the system, including retrofit design improvements to existing systems. The coupled CFD and kinetic computer code are used in combination with data obtained from a matrix of experimental tests to extract the kinetic constants. Local fluid dynamic effects are implicitly included in the extracted local kinetic constants for each particular application system to which the methodology is applied. The extracted local kinetic model constants work well over a fairly broad range of operating conditions for specific and complex reaction sets in specific and complex reactor systems. While disclosed in terms of use in a Fluid Catalytic Cracking (FCC) riser, the inventive methodology has application in virtually any reaction set to extract constants for any particular application and reaction set formulation. The methodology includes the step of: (1) selecting the test data sets for various conditions; (2) establishing the general trend of the parametric effect on the measured product yields; (3) calculating product yields for the selected test conditions using coupled computational fluid dynamics and chemical kinetics; (4) adjusting the local kinetic constants to match calculated product yields with experimental data; and (5) validating the determined set of local kinetic constants by comparing the calculated results with experimental data from additional test runs at different operating conditions.
A Mathematical Framework for Online Constant Coefficient Multiplication
Directory of Open Access Journals (Sweden)
Georgina Binoy Joseph
2017-06-01
Full Text Available Single and Multiple constant multiplications are key operations in several digital signal processing algorithms. This paper develops a mathematical framework for a novel adaptation of the parallel shift-and-add multiplication algorithm for online arithmetic. Based on this adaptation, online constant coefficient multipliers for single constant multiplication (SCM and multiple constant multiplications (MCM of streaming floating-point inputs are presented. A finite impulse response filter implementation on Xilinx Virtex 6 Field programmable gate array (FPGA is used as an example to illustrate the merits of these filters. The results of this implementation show that online multipliers reduce resource utilization, online delay and increase clock frequency in comparison to existing designs. Online multiple constant multipliers also show an average reduction of 65% in the number of slice LUTs and 37% in the number of slice registers required when compared to existing digit-serial multiple constant multipliers. Thus, the proposed online arithmetic operators appear to be good alternatives for constant coefficient multiplication
Computing the Gromov hyperbolicity constant of a discrete metric space
Ismail, Anas
2012-07-01
Although it was invented by Mikhail Gromov, in 1987, to describe some family of groups[1], the notion of Gromov hyperbolicity has many applications and interpretations in different fields. It has applications in Biology, Networking, Graph Theory, and many other areas of research. The Gromov hyperbolicity constant of several families of graphs and geometric spaces has been determined. However, so far, the only known algorithm for calculating the Gromov hyperbolicity constant δ of a discrete metric space is the brute force algorithm with running time O (n4) using the four-point condition. In this thesis, we first introduce an approximation algorithm which calculates a O (log n)-approximation of the hyperbolicity constant δ, based on a layering approach, in time O(n2), where n is the number of points in the metric space. We also calculate the fixed base point hyperbolicity constant δr for a fixed point r using a (max, min)−matrix multiplication algorithm by Duan in time O(n2.688)[2]. We use this result to present a 2-approximation algorithm for calculating the hyper-bolicity constant in time O(n2.688). We also provide an exact algorithm to compute the hyperbolicity constant δ in time O(n3.688) for a discrete metric space. We then present some partial results we obtained for designing some approximation algorithms to compute the hyperbolicity constant δ.
Constant-roll inflation in F(R) gravity
Nojiri, S.; Odintsov, S. D.; Oikonomou, V. K.
2017-12-01
In this paper, we study constant-roll inflation in F(R) gravity. We take two different approaches, one that relates F(R) gravity to well-known scalar models of constant-roll and a second that examines the constant-roll condition in F(R) gravity directly. With regard to the first approach, by using well-known techniques, we find the F(R) gravity that realizes a given constant-roll evolution in the scalar-tensor theory. We also perform a conformal transformation in the resulting F(R) gravity and find the Einstein frame counterpart theory. As we demonstrate, the resulting scalar potential is different in comparison to the original scalar constant-roll case, and the same applies for the corresponding observational indices. Moreover, we discuss how cosmological evolutions that can realize constant-roll to constant-roll era transitions in the scalar-tensor description can be realized by vacuum F(R) gravity. With regard to the second approach, we examine the effects of the constant-roll condition on the inflationary dynamics of vacuum F(R) gravity directly. We present in detail the formalism of constant-roll F(R) gravity inflationary dynamics and we discuss the inflationary indices for this case. We use two well-known F(R) gravities in order to illustrate our findings: the R 2 model and a power-law F(R) gravity in vacuum. As we demonstrate, in both cases the parameter space is enlarged in comparison to the slow-roll counterparts of the models and, in effect, the models can also be compatible with the observational data. Finally, we briefly address the graceful exit issue.
Ramirez de Noriega, Fernando; Eitan, Renana; Marmor, Odeya; Lavi, Adi; Linetzky, Eduard; Bergman, Hagai; Israel, Zvi
2015-02-18
Background: Subthalamic nucleus (STN) deep brain stimulation (DBS) is an established therapy for advanced Parkinson's disease (PD). Motor efficacy and safety have been established for constant voltage (CV) devices and more recently for constant current (CC) devices. CC devices adjust output voltage to provide CC stimulation irrespective of impedance fluctuation, while the current applied by CV stimulation depends on the impedance that may change over time. No study has directly compared the clinical effects of these two stimulation modalities. Objective: To compare the safety and clinical impact of CC STN DBS to CV STN DBS in patients with advanced PD 2 years after surgery. Methods: Patients were eligible for inclusion if they had undergone STN DBS surgery for idiopathic PD, had been implanted with a Medtronic Activa PC and if their stimulation program and medication had been stable for at least 1 year. This single-center trial was designed as a double-blind, randomized, prospective study with crossover after 2 weeks. Motor equivalence of the 2 modalities was confirmed utilizing part III of the Unified Parkinson's Disease Rating Scale (UPDRS). PD diaries and multiple subjective and objective evaluations of quality of life, depression, cognition and emotional processing were evaluated on both CV and on CC stimulation. Analysis using the paired t test with Bonferroni correction for multiple comparisons was performed to identify any significant difference between the stimulation modalities. Results: 8 patients were recruited (6 men, 2 women); 1 patient did not complete the study. The average age at surgery was 56.7 years (range 47-63). Disease duration at the time of surgery was 7.5 years (range 3-12). Patients were recruited 23.8 months (range 22.5-24) after surgery. At the postoperative study baseline, this patient group showed an average motor improvement of 69% (range 51-97) as measured by the change in UPDRS part III with stimulation alone. Levodopa equivalent
Mach, Patryk; Karkowski, Janusz
2013-01-01
We investigate spherical, isothermal and polytropic steady accretion models in the presence of the cosmological constant. Exact solutions are found for three classes of isothermal fluids, assuming the test gas approximation. The cosmological constant damps the mass accretion rate and - above certain limit - completely stops the steady accretion onto black holes. A "homoclinic-type" accretion flow of polytropic gas has been discovered in AdS spacetimes in the test-gas limit. These results can have cosmological connotation, through the Einstein--Straus vacuole model of embedding local structures into Friedman-Lemaitre-Robertson-Walker spacetimes. In particular one infers that steady accretion would not exist in the late phases of the Penrose's scenario of the evolution of the Universe, known as the Weyl curvature hypothesis.
DEFF Research Database (Denmark)
Rosenberg, J; Oturai, P; Erichsen, C J
1994-01-01
STUDY OBJECTIVE: To evaluate the relative contribution of general anesthesia alone and in combination with the surgical procedure to the pathogenesis of late postoperative hypoxemia. DESIGN: Open, controlled study. SETTING: University hospital. PATIENTS: 60 patients undergoing major abdominal...... surgery and 16 patients undergoing middle ear surgery, both with comparable general anesthesia. MEASUREMENTS AND MAIN RESULTS: Patients were monitored with continuous pulse oximetry on one preoperative night and the second postoperative night. Significant episodic or constant hypoxemia did not occur...... on the second postoperative night following middle ear surgery and general anesthesia, but severe episodic and constant hypoxemia did occur on the second postoperative after major abdominal surgery and general anesthesia. CONCLUSIONS: General anesthesia in itself is not an important factor in the development...
Mach, Patryk; Malec, Edward; Karkowski, Janusz
2013-10-01
We investigate spherical, isothermal and polytropic steady accretion models in the presence of the cosmological constant. Exact solutions are found for three classes of isothermal fluids, assuming the test gas approximation. The cosmological constant damps the mass accretion rate and—above a certain limit—completely stops the steady accretion onto black holes. A “homoclinic-type” accretion flow of polytropic gas has been discovered in anti-de Sitter spacetimes in the test-gas limit. These results can have cosmological connotation, through the Einstein-Straus vacuole model of embedding local structures into Friedman-Lemaitre-Robertson-Walker spacetimes. In particular, one infers that steady accretion would not exist in the late phases of Penrose’s scenario of the evolution of the Universe, known as the Weyl curvature hypothesis.
Implications of Time Varying Cosmological Constant on Kaluza-Klein Cosmological Model
Jain, Namrata I.; Bhoga, S. S.; Khadekar, G. S.
2013-12-01
In this paper, the cosmological model with variable in Kaluza-Klein metric have been studied. Here α and β are dimensionless parameters. The solutions to Einstein field equations which assume that the Universe is filled with perfect fluid have been obtained by using the Gamma Law Equation p=( γ-1) ρ; in which the parameter γ is constant and power law equation A( t)= R n ( t)—where A( t) is scale factor for extra dimension and R( t) is scale factor for space dimensions. The fifth dimension for the radiation dominated phases is more prominent with this model. Other physical parameters i.e. density, pressure, deceleration parameter, Hubble parameter have been determined for this model. It is observed physical parameters depends upon constants α, β and n. Neo-classical tests have also been studied in this paper.
Farmer's lung in Ireland (1983-1996) remains at a constant level.
LENUS (Irish Health Repository)
McGrath, D S
2012-02-03
A prospective study was undertaken by the Departments of Respiratory Medicine and Medical Microbiology at the Cork University Hospital, a. to investigate the epidemiology of Farmer\\'s Lung (F.L.) in the Republic of Ireland (pop. 3.5 million), with special reference to the South Western Region of this country (pop. 536,000) and b. to assess any relationship between the prevalence\\/incidence of F.L. with climatic factors in South West Ireland, between 1983 and 1996. F.L. incidence remained constant throughout the 13 yrs studied both on a national and a regional basis. A significant relationship was also found between total rainfall each summer and F.L. incidence and prevalence over the following yr (p < 0.005) in South-West Ireland. The persistence of F.L. in Ireland at a constant level suggests that farmers\\' working environment and farm practices need to be improved.
Time variation of fundamental constants in nonstandard cosmological models
Mosquera, M. E.; Civitarese, O.
2017-10-01
In this work we have studied the lithium problem in nonstandard cosmological models. In particular, by using the public code alterbbn, we have included in the computation of the primordial light nuclei abundances, the effects of the inclusion of dark energy and dark entropy, along with the variation of the fine structure constant and the Higgs vacuum expectation value. In order to set constrains on the variation of the fundamental constants we have compared our theoretical results with the available observational data. We have found that the lithium abundance is reduced for not-null variation at the 3 σ -level of both constants.
Large numbers hypothesis. IV - The cosmological constant and quantum physics
Adams, P. J.
1983-01-01
In standard physics quantum field theory is based on a flat vacuum space-time. This quantum field theory predicts a nonzero cosmological constant. Hence the gravitational field equations do not admit a flat vacuum space-time. This dilemma is resolved using the units covariant gravitational field equations. This paper shows that the field equations admit a flat vacuum space-time with nonzero cosmological constant if and only if the canonical LNH is valid. This allows an interpretation of the LNH phenomena in terms of a time-dependent vacuum state. If this is correct then the cosmological constant must be positive.
High precision fundamental constants at the TeV scale
Moch, S.; Alekhin, S.; Blumlein, J.; de la Cruz, L.; Dittmaier, S.; Dowling, M.; Erler, J.; Espinosa, J.R.; Fuster, J.; Garcia i Tormo, X.; Hoang, A.H.; Huss, A.; Kluth, S.; Mulders, M.; Papanastasiou, A.S.; Piclum, J.; Rabbertz, K.; Schwinn, C.; Schulze, M.; Shintani, E.; Uwer, P.; Zerf, N.
2014-01-01
This report summarizes the proceedings of the 2014 Mainz Institute for Theoretical Physics (MITP) scientific program on "High precision fundamental constants at the TeV scale". The two outstanding parameters in the Standard Model dealt with during the MITP scientific program are the strong coupling constant $\\alpha_s$ and the top-quark mass $m_t$. Lacking knowledge on the value of those fundamental constants is often the limiting factor in the accuracy of theoretical predictions. The current status on $\\alpha_s$ and $m_t$ has been reviewed and directions for future research have been identified.
Procedures for determining MATMOD-4V material constants
Energy Technology Data Exchange (ETDEWEB)
Lowe, T.C.
1993-11-01
The MATMOD-4V constitutive relations were developed from the original MATMOD model to extend the range of nonelastic deformation behaviors represented to include transient phenomena such as strain softening. Improvements in MATMOD-4V increased the number of independent material constants and the difficulty in determining their values. Though the constitutive relations are conceptually simple, their form and procedures for obtaining their constants can be complex. This paper reviews in detail the experiments, numerical procedures, and assumptions that have been used to determine a complete set of MATMOD-4V constants for high purity aluminum.
Compilation of Henry's law constants, version 3.99
Sander, R.
2014-11-01
Many atmospheric chemicals occur in the gas phase as well as in liquid cloud droplets and aerosol particles. Therefore, it is necessary to understand the distribution between the phases. According to Henry's law, the equilibrium ratio between the abundances in the gas phase and in the aqueous phase is constant for a dilute solution. Henry's law constants of trace gases of potential importance in environmental chemistry have been collected and converted into a uniform format. The compilation contains 14775 values of Henry's law constants for 3214 species, collected from 639 references. It is also available on the internet at law.org">http://www.henrys-law.org.
Magnetic system for small betatron with constant guide field
Energy Technology Data Exchange (ETDEWEB)
Chakhlov, V.L.; Zvontsov, A.A.; Simukhin, N.F.
1975-07-01
It is known that the use of guide fields that are constant in time in cyclic accelerators leads to an increase of the average intensity, owing to the relative long time of injection of the particles into the acceleration regime. In the design of induction accelerators with time-constant control fields, preference is given to radial-sector magnetic systems, but for similar accelerators designed for low and medium energies it is also convenient to use a spiral-sector design. A model of a magnetic system for a betatron with constant field is described.
PIV measurement of constant area mixing in subsonic air ejector
Directory of Open Access Journals (Sweden)
Dvořák Václav
2012-04-01
Full Text Available The article deals with experimental study of constant area mixing in subsonic axi-symmetric air ejector. The velocity fields inside the constant area mixing chamber were taken through the vitreous wall of the chamber, while the laser beam entered it from the opened outflow of the ejector. PIV measurements of four different mixing regimes, each with different ejection ratio were performed. Basic description of results are given and it is claimed that results are reliable. Obtained data will be later compared with constant temperature anemometry and with numerical calculations.
Experimental determination of the effective strong coupling constant
Energy Technology Data Exchange (ETDEWEB)
Alexandre Deur; Volker Burkert; Jian-Ping Chen; Wolfgang Korsch
2007-07-01
We extract an effective strong coupling constant from low Q{sup 2} data on the Bjorken sum. Using sum rules, we establish its Q{sup 2}-behavior over the complete Q{sup 2}-range. The result is compared to effective coupling constants extracted from different processes and to calculations based on Schwinger-Dyson equations, hadron spectroscopy or lattice QCD. Although the connection between the experimentally extracted effective coupling constant and the calculations is not clear, the results agree surprisingly well.
Ionisation constants of inorganic acids and bases in aqueous solution
Perrin, D D
2013-01-01
Ionisation Constants of Inorganic Acids and Bases in Aqueous Solution, Second Edition provides a compilation of tables that summarize relevant data recorded in the literature up to the end of 1980 for the ionization constants of inorganic acids and bases in aqueous solution. This book includes references to acidity functions for strong acids and bases, as well as details about the formation of polynuclear species. This text then explains the details of each column of the tables, wherein column 1 gives the name of the substance and the negative logarithm of the ionization constant and column 2
Zhu, P. Y.; Fung, A. K.
1986-01-01
The effective medium approximation (EMA) formalism developed for scalar wave calculations in solid state physics is generalized to electromagnetic wave scattering in a dense random medium. Results are applied to compute the effective propagation constant in a dense medium involving discrete spherical scatterers. When compared with a common quasicrystalline approximation (QCA), it is found that EMA accounts for backward scattering and the effect of correlation among three scatterers which are not available in QCA. It is also found that there is not much difference in the calculated normalized phase velocity between the use of these two approximations. However, there is a significant difference in the computed effective loss tangent in a nonabsorptive random medium. The computed effective loss tangent using EMA and measurements from a snow medium are compared, showing good agreement.
Turbulent Heat Transfer Behavior of Nanofluid in a Circular Tube Heated under Constant Heat Flux
Directory of Open Access Journals (Sweden)
Shuichi Torii
2010-01-01
Full Text Available The aim of the present study is to disclose the forced convective heat transport phenomenon of nanofluids inside a horizontal circular tube subject to a constant and uniform heat flux at the wall. Consideration is given to the effect of the inclusion of nanoparticles on heat transfer enhancement, thermal conductivity, viscosity, and pressure loss in the turbulent flow region. It is found that (i heat transfer enhancement is caused by suspending nanoparticles and becomes more pronounced with the increase of the particle volume fraction, (ii its augmentation is affected by three different nanofluids employed here, and (iii the presence of particles produces adverse effects on viscosity and pressure loss that also increases with the particle volume fraction.
Wagner, Marise M.; Visser, Jantien; Verburg, Harjo; Hukkelhoven, Chantal W. P. M.; van Lith, Jan M. M.; Bloemenkamp, Kitty W. M.
2018-01-01
The cause of recurrent pregnancy loss often remains unknown. Possibly, pathophysiological pathways are shared with other pregnancy complications. All women with secondary recurrent pregnancy loss (SRPL) visiting Leiden University Medical Center (January 2000-2015) were included in this retrospective
Halsøy, Kathrine; Kondratiev, Timofey; Tveita, Torkjel; Bjertnaes, Lars J
2016-01-01
Victims of severe accidental hypothermia are prone to fluid extravasation but rarely develop lung edema. We hypothesize that combined hypothermia-induced increase in pulmonary vascular resistance (PVR) and a concomitant fall in cardiac output protect the lungs against edema development. Our aim was to explore in hypothermic-isolated blood-perfused rat lungs whether perfusion at constant pressure influences fluid filtration differently from perfusion at constant flow. Isolated blood-perfused rat lungs were hanging freely in a weight transducer for measuring weight changes (ΔW). Fluid filtration coefficient (Kfc), was determined by transiently elevating left atrial pressure (Pla) by 5.8 mmHg two times each during normothermia (37°C) and during hypothermia (15°C). The lung preparations were randomized to two groups. One group was perfused with constant flow (Constant flow group) and the other group with constant pulmonary artery pressure (Constant PPA group). Microvascular pressure (Pmv) was determined before and during elevation of Pla (ΔPmv) by means of the double occlusion technique. Kfc was calculated with the formula Kfc = ΔW/ΔPmv/min. All Kfc values were normalized to predicted lung weight (PLW), which was based on body weight (BW) according to the formula: PLW = 0.0053 BW - 0.48 and presented as KfcPLW in mg/min/mmHg/g. At cessation, bronchoalveolar lavage (BAL) fluid/perfusate protein concentration (B/P) ratio was determined photometrically. Data were analyzed with parametric or non-parametric tests as appropriate. p < 0.05 considered as significant. Perfusate flow remained constant in the Constant flow group, but was more than halved during hypothermia in the Constant PPA group concomitant with a more fold increase in PVR. In the Constant flow group, KfcPLW and B/P ratio increased significantly by more than 10-fold during hypothermia concerted by visible signs of edema in the trachea. Hemoglobin and hematocrit increased within the
A gravitational-wave standard siren measurement of the Hubble constant.
2017-11-02
On 17 August 2017, the Advanced LIGO and Virgo detectors observed the gravitational-wave event GW170817-a strong signal from the merger of a binary neutron-star system. Less than two seconds after the merger, a γ-ray burst (GRB 170817A) was detected within a region of the sky consistent with the LIGO-Virgo-derived location of the gravitational-wave source. This sky region was subsequently observed by optical astronomy facilities, resulting in the identification of an optical transient signal within about ten arcseconds of the galaxy NGC 4993. This detection of GW170817 in both gravitational waves and electromagnetic waves represents the first 'multi-messenger' astronomical observation. Such observations enable GW170817 to be used as a 'standard siren' (meaning that the absolute distance to the source can be determined directly from the gravitational-wave measurements) to measure the Hubble constant. This quantity represents the local expansion rate of the Universe, sets the overall scale of the Universe and is of fundamental importance to cosmology. Here we report a measurement of the Hubble constant that combines the distance to the source inferred purely from the gravitational-wave signal with the recession velocity inferred from measurements of the redshift using the electromagnetic data. In contrast to previous measurements, ours does not require the use of a cosmic 'distance ladder': the gravitational-wave analysis can be used to estimate the luminosity distance out to cosmological scales directly, without the use of intermediate astronomical distance measurements. We determine the Hubble constant to be about 70 kilometres per second per megaparsec. This value is consistent with existing measurements, while being completely independent of them. Additional standard siren measurements from future gravitational-wave sources will enable the Hubble constant to be constrained to high precision.
A gravitational-wave standard siren measurement of the Hubble constant
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X.; Ramirez-Ruiz, E.; Rest, A.; Rojas-Bravo, C.; Shappee, B. J.; Siebert, M. R.; Simon, J. D.; Ulloa, N.; Annis, J.; Soares-Santos, M.; Brout, D.; Scolnic, D.; Diehl, H. T.; Frieman, J.; Berger, E.; Alexander, K. D.; Allam, S.; Balbinot, E.; Blanchard, P.; Butler, R. E.; Chornock, R.; Cook, E. R.; Cowperthwaite, P.; Drlica-Wagner, A.; Drout, M. R.; Durret, F.; Eftekhari, T.; Finley, D. A.; Fong, W.; Fryer, C. L.; García-Bellido, J.; Gill, M. S. S.; Gruendl, R. A.; Hanna, C.; Hartley, W.; Herner, K.; Huterer, D.; Kasen, D.; Kessler, R.; Li, T. S.; Lin, H.; Lopes, P. A. A.; Lourenço, A. C. C.; Margutti, R.; Marriner, J.; Marshall, J. L.; Matheson, T.; Medina, G. E.; Metzger, B. D.; Muñoz, R. R.; Muir, J.; Nicholl, M.; Nugent, P.; Palmese, A.; Paz-Chinchón, F.; Quataert, E.; Sako, M.; Sauseda, M.; Schlegel, D. J.; Secco, L. F.; Smith, N.; Sobreira, F.; Stebbins, A.; Villar, V. A.; Vivas, A. K.; Wester, W.; Williams, P. K. G.; Yanny, B.; Zenteno, A.; Abbott, T. M. C.; Abdalla, F. B.; Bechtol, K.; Benoit-Lévy, A.; Bertin, E.; Bridle, S. L.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Castander, F. J.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Davis, C.; Depoy, D. L.; Desai, S.; Dietrich, J. P.; Estrada, J.; Fernandez, E.; Flaugher, B.; Fosalba, P.; Gaztanaga, E.; Gerdes, D. W.; Giannantonio, T.; Goldstein, D. A.; Gruen, D.; Gutierrez, G.; Hartley, W. G.; Honscheid, K.; Jain, B.; James, D. J.; Jeltema, T.; Johnson, M. W. G.; Kent, S.; Krause, E.; Kron, R.; Kuehn, K.; Kuhlmann, S.; Kuropatkin, N.; Lahav, O.; Lima, M.; Maia, M. A. G.; March, M.; Miller, C. J.; Miquel, R.; Neilsen, E.; Nord, B.; Ogando, R. L. C.; Plazas, A. A.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, M.; Smith, R. C.; Suchyta, E.; Tarle, G.; Thomas, D.; Thomas, R. C.; Troxel, M. A.; Tucker, D. L.; Vikram, V.; Walker, A. R.; Weller, J.; Zhang, Y.; Haislip, J. B.; Kouprianov, V. V.; Reichart, D. E.; Tartaglia, L.; Sand, D. J.; Valenti, S.; Yang, S.; Arcavi, Iair; Hosseinzadeh, Griffin; Howell, D. Andrew; McCully, Curtis; Poznanski, Dovi; Vasylyev, Sergiy; Tanvir, N. R.; Levan, A. J.; Hjorth, J.; Cano, Z.; Copperwheat, C.; de Ugarte-Postigo, A.; Evans, P. A.; Fynbo, J. P. U.; González-Fernández, C.; Greiner, J.; Irwin, M.; Lyman, J.; Mandel, I.; McMahon, R.; Milvang-Jensen, B.; O'Brien, P.; Osborne, J. P.; Perley, D. A.; Pian, E.; Palazzi, E.; Rol, E.; Rosetti, S.; Rosswog, S.; Rowlinson, A.; Schulze, S.; Steeghs, D. T. H.; Thöne, C. C.; Ulaczyk, K.; Watson, D.; Wiersema, K.; Lipunov, V. M.; Gorbovskoy, E.; Kornilov, V. G.; Tyurina, N.; Balanutsa, P.; Vlasenko, D.; Gorbunov, I.; Podesta, R.; Levato, H.; Saffe, C.; Buckley, D. A. H.; Budnev, N. M.; Gress, O.; Yurkov, V.; Rebolo, R.; Serra-Ricart, M.
2017-11-01
On 17 August 2017, the Advanced LIGO and Virgo detectors observed the gravitational-wave event GW170817—a strong signal from the merger of a binary neutron-star system. Less than two seconds after the merger, a γ-ray burst (GRB 170817A) was detected within a region of the sky consistent with the LIGO-Virgo-derived location of the gravitational-wave source. This sky region was subsequently observed by optical astronomy facilities, resulting in the identification of an optical transient signal within about ten arcseconds of the galaxy NGC 4993. This detection of GW170817 in both gravitational waves and electromagnetic waves represents the first ‘multi-messenger’ astronomical observation. Such observations enable GW170817 to be used as a ‘standard siren’ (meaning that the absolute distance to the source can be determined directly from the gravitational-wave measurements) to measure the Hubble constant. This quantity represents the local expansion rate of the Universe, sets the overall scale of the Universe and is of fundamental importance to cosmology. Here we report a measurement of the Hubble constant that combines the distance to the source inferred purely from the gravitational-wave signal with the recession velocity inferred from measurements of the redshift using the electromagnetic data. In contrast to previous measurements, ours does not require the use of a cosmic ‘distance ladder’: the gravitational-wave analysis can be used to estimate the luminosity distance out to cosmological scales directly, without the use of intermediate astronomical distance measurements. We determine the Hubble constant to be about 70 kilometres per second per megaparsec. This value is consistent with existing measurements, while being completely independent of them. Additional standard siren measurements from future gravitational-wave sources will enable the Hubble constant to be constrained to high precision.
Bahcall, Neta A.
2015-01-01
Most of the mass in the universe is in the form of dark matter—a new type of nonbaryonic particle not yet detected in the laboratory or in other detection experiments. The evidence for the existence of dark matter through its gravitational impact is clear in astronomical observations—from the early observations of the large motions of galaxies in clusters and the motions of stars and gas in galaxies, to observations of the large-scale structure in the universe, gravitational lensing, and the cosmic microwave background. The extensive data consistently show the dominance of dark matter and quantify its amount and distribution, assuming general relativity is valid. The data inform us that the dark matter is nonbaryonic, is “cold” (i.e., moves nonrelativistically in the early universe), and interacts only weakly with matter other than by gravity. The current Lambda cold dark matter cosmology—a simple (but strange) flat cold dark matter model dominated by a cosmological constant Lambda, with only six basic parameters (including the density of matter and of baryons, the initial mass fluctuations amplitude and its scale dependence, and the age of the universe and of the first stars)—fits remarkably well all the accumulated data. However, what is the dark matter? This is one of the most fundamental open questions in cosmology and particle physics. Its existence requires an extension of our current understanding of particle physics or otherwise point to a modification of gravity on cosmological scales. The exploration and ultimate detection of dark matter are led by experiments for direct and indirect detection of this yet mysterious particle. PMID:26417091
Bahcall, Neta A
2015-10-06
Most of the mass in the universe is in the form of dark matter--a new type of nonbaryonic particle not yet detected in the laboratory or in other detection experiments. The evidence for the existence of dark matter through its gravitational impact is clear in astronomical observations--from the early observations of the large motions of galaxies in clusters and the motions of stars and gas in galaxies, to observations of the large-scale structure in the universe, gravitational lensing, and the cosmic microwave background. The extensive data consistently show the dominance of dark matter and quantify its amount and distribution, assuming general relativity is valid. The data inform us that the dark matter is nonbaryonic, is "cold" (i.e., moves nonrelativistically in the early universe), and interacts only weakly with matter other than by gravity. The current Lambda cold dark matter cosmology--a simple (but strange) flat cold dark matter model dominated by a cosmological constant Lambda, with only six basic parameters (including the density of matter and of baryons, the initial mass fluctuations amplitude and its scale dependence, and the age of the universe and of the first stars)--fits remarkably well all the accumulated data. However, what is the dark matter? This is one of the most fundamental open questions in cosmology and particle physics. Its existence requires an extension of our current understanding of particle physics or otherwise point to a modification of gravity on cosmological scales. The exploration and ultimate detection of dark matter are led by experiments for direct and indirect detection of this yet mysterious particle.
The osteoimmunology of alveolar bone loss.
Tompkins, Kevin A
2016-01-01
The mineralized structure of bone undergoes constant remodeling by the balanced actions of bone-producing osteoblasts and bone-resorbing osteoclasts (OCLs). Physiologic bone remodeling occurs in response to the body's need to respond to changes in electrolyte levels, or mechanical forces on bone. There are many pathological conditions, however, that cause an imbalance between bone production and resorption due to excessive OCL action that results in net bone loss. Situations involving chronic or acute inflammation are often associated with net bone loss, and research into understanding the mechanisms regulating this bone loss has led to the development of the field of osteoimmunology. It is now evident that the skeletal and immune systems are functionally linked and share common cells and signaling molecules. This review discusses the signaling system of immune cells and cytokines regulating aberrant OCL differentiation and activity. The role of these cells and cytokines in the bone loss occurring in periodontal disease (PD) (chronic inflammation) and orthodontic tooth movement (OTM) (acute inflammation) is then described. The review finishes with an exploration of the emerging role of Notch signaling in the development of the immune cells and OCLs that are involved in osteoimmunological bone loss and the research into Notch signaling in OTM and PD.
Schubert, C. R.; Cruickshanks, K. J.; Wiley, T. L.; Klein, R.; Klein, B E; Tweed, T. S.
2001-01-01
OBJECTIVE: To determine if infectious diseases usually experienced in childhood have an effect on hearing ability later in life. METHODS: The Epidemiology of Hearing Loss Study (N = 3,753) is a population-based study of age-related hearing loss in adults aged 48 to 92 years in Beaver Dam, Wisconsin. As part of this study, infectious disease history was obtained and hearing was tested using pure-tone audiometry. Hearing loss was defined as a pure-tone average of thresholds at 500 Hz, 1,000 Hz,...
Energy Technology Data Exchange (ETDEWEB)
Dotsenko, Viktor S [Landau Institute for Theoretical Physics, Russian Academy of Sciences, Moscow (Russian Federation)
2011-03-31
In the last two decades, it has been established that a single universal probability distribution function, known as the Tracy-Widom (TW) distribution, in many cases provides a macroscopic-level description of the statistical properties of microscopically different systems, including both purely mathematical ones, such as increasing subsequences in random permutations, and quite physical ones, such as directed polymers in random media or polynuclear crystal growth. In the first part of this review, we use a number of models to examine this phenomenon at a simple qualitative level and then consider the exact solution for one-dimensional directed polymers in a random environment, showing that free energy fluctuations in such a system are described by the universal TW distribution. The second part provides detailed appendix material containing the necessary mathematical background for the first part. (reviews of topical problems)
Directory of Open Access Journals (Sweden)
Miguel Zabalza Beraza
2013-01-01
Full Text Available Writing in the University is a basic necessity and a long-range educational purpose. One of the basic characteristics of the university context is that it requires writing both as a tool of communication and as a source of intellectual stimulation. After establishing the basic features of academic writing, this article analyzes the role of writing for students (writing to learn and for teachers (write to plan, to reflect, to document what has been done. The article also discusses the contributions of writing for both students and teachers together: writing to investigate. Finally, going beyond what writing is as academic tool, we conclude with a more playful and creative position: writing for pleasure and enjoyment.
Is hearing loss a feature of Joubert syndrome, a ciliopathy?
Kroes, H.Y.; Van Zanten, B.G.A.; De Ru, S.A.; Boon, M.; Mancini, G.M.S.; van der Knaap, M.S.; Poll-The, B.; Lindhout, D.
2010-01-01
Objective: To assess if hearing loss is a feature of Joubert syndrome (JBS), one of the ciliopathies and therefore possibly associated with hearing loss. Design: Retrospective case series. Setting: University Children's Hospital. Patients: Dutch patients with JBS. Main outcome measures: Audiological
Is hearing loss a feature of Joubert syndrome, a ciliopathy?
Kroes, Hester Y.; van Zanten, Bert G. A.; de Ru, Sander A.; Boon, Maartje; Mancini, Grazia M. S.; van der Knaap, Marjo S.; Poll-The, Bwee Tien; Lindhout, Dick
2010-01-01
Objective To assess if hearing loss is a feature of Joubert syndrome (JBS). one of the ciliopathies and therefore possibly associated with hearing loss Design: Retrospective case series. Setting University Children's Hospital Patients Dutch patients with JBS. Main outcome measures Audiological data.
Is hearing loss a feature of Joubert syndrome, a ciliopathy?
Kroes, Hester Y.; Van Zanten, Bert G. A.; De Ru, Sander A.; Boon, Maartje; Mancini, Grazia M. S.; Van der Knaap, Marjo S.; Poll-The, Bwee Tien; Lindhout, Dick
Objective To assess if hearing loss is a feature of Joubert syndrome (JBS). one of the ciliopathies and therefore possibly associated with hearing loss Design: Retrospective case series. Setting University Children's Hospital Patients Dutch patients with JBS. Main outcome measures Audiological data.
Water loss during incubation in red bishop (Euplectes
African Journals Online (AJOL)
Parry. Institute of Natural Resources, University of Natal, P.O. Box 37S,. Pietermaritzburg 3200, Republic of South Africa. ·To whom correspondence should be addressed. Received 10 August 1981; accepted 18 September 1981. Avian eggs lose weight during incubation and this weight loss, almost entirely due to water loss ...
Vagnini, Michael T; Rutledge, W Caleb; Wagenknecht, Paul S
2010-02-01
Electronic energy transfer can fall into two limiting cases. When the rate of the energy transfer back reaction is much faster than relaxation of the acceptor excited state, equilibrium between the donor and acceptor excited states is achieved and only the equilibrium constant for the energy transfer can be measured. When the rate of the back reaction is much slower than relaxation of the acceptor, the energy transfer is irreversible and only the forward rate constant can be measured. Herein, we demonstrate that with trans-[Cr(d(4)-cyclam)(CN)(2)](+) as the donor and either trans-[Cr([15]ane-ane-N(4))(CN)(2)](+) or trans-[Cr(cyclam)(CN)(2)](+) as the acceptor, both limits can be obtained by control of the donor concentration. The equilibrium constant and rate constant for the case in which trans-[Cr([15]ane-ane-N(4))(CN)(2)](+) is the acceptor are 0.66 and 1.7 x 10(7) M(-1) s(-1), respectively. The equilibrium constant is in good agreement with the value of 0.60 determined using the excited state energy gap between the donor and acceptor species. For the thermoneutral case in which trans-[Cr(cyclam)(CN)(2)](+) is the acceptor, an experimental equilibrium constant of 0.99 was reported previously, and the rate constant has now been measured as 4.0 x 10(7) M(-1) s(-1).
VLT and E-ELT spectrographs & fundamental-constants
Molaro, Paolo
2010-11-01
The fundamental dimensionless physical constants cannot be predicted by theory but can only be measured experimentally. And so it is of their possible variation where there are several theoretical predictions but unfortunately with little theoretical guidance on the expected rate of change. The role of fundamental constants in the representation of nature as well as the implications of their variability for the Equivalence Principle and cosmology have been highlighted in many contributions at this conference (cfr K. Olive and J.P Uzan, these proceedings). Measuring the variability of the fine structure constant α or the electron-to-proton ratio μ by means of absorption lines implies the measurement of a tiny variation of the position of one or a few lines with regard to other lines which are taken as reference. For the fine structure constant the relation between its change and the doppler velocity shift is:
[Grades evaluation of Scutellariae Radix slices based on quality constant].
Deng, Zhe; Zhang, Jun; Jiao, Meng-Jiao; Zhong, Wen; Cui, Wen-Jin; Cheng, Jin-Tang; Chen, Sha; Wang, Yue-Sheng; Liu, An
2017-05-01
By measuring the morphological indexes and the marker components content of 22 batches of Scutellariae Radix slices as well as calculating the quality constant, this research was aimed to establish a new method of evaluating the specifications and grades of Scutellariae Radix slices. The quality constants of these samples were in the range of 0.04-0.49, which can be divided into several grades based on the real requirement. If they were divided into three grades, the quality constant was ≥0.39 for the first grade, grade, and grade. This work indicated that the quality constants characterizing both apparent parameters and intrinsic quality can be used as a comprehensive evaluation index to classify the grades of traditional Chinese medicine quantitatively, clearly and objectively. The research results in this paper would provide new ideas and references for evaluating the specifications and grades of traditional Chinese medicines. Copyright© by the Chinese Pharmaceutical Association.
The Length-Weight Relationship and Condition Factor (K constant ...
African Journals Online (AJOL)
The Length-Weight Relationship and Condition Factor (K constant) of the Sparidae (Dentex Marocannus, Valenciennes 1830) of Malindi, Kenya. Christopher Mulanda Aura, Rashid Oketch Anam, Safina Musa, Edward Ndirui Kimani ...
National Aeronautics and Space Administration — The MAC0NXASM or const_2d_asm_Nx data product is the MERRA Data Assimilation System 2-Dimensional Constants at native resolution. MERRA, or the Modern Era...
Projectile Motion with Quadratic Damping in a Constant ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 5. Projectile Motion with Quadratic Damping in a Constant Gravitational Field. Chandra Das Dhiranjan Roy. General Article Volume 19 Issue 5 May 2014 pp 446-465 ...
Optical constant determination of thin polymer films in the infrared
Graf, R. T.; Koenig, J. L.; Ishida, H.
1984-08-01
Thin films of poly(vinyl chloride), poly(methyl methacrylate), and poly(styrene) were analyzed by Fourier transform infrared spectroscopy. The interference fringes present in the transmission spectra of these samples were used to determine thickness and average refractive index (in non-absorbing regions). Subsequent Kramers-Kronig analysis of these transmission spectra provided the the dispersion of the refractive index and the absorptive index across the entire mid-infrared region. The refractive index and the absorptive index, collectively known as the optical constants, are intrinsic properties of a material, and their spectra are invariant with respect to the geometry and/or thickness of a sample. The intrinsic nature of the derived optical constants was verified by the absence of interference fringes in the optical constant spectra, and by the good agreement obtained between our optical constant spectra and those of other authors.