A variational theory of the BCS pair-condensed state of strongly-interacting Fermi system is briefly outlined. An FHNC scheme is devised to calculate the radial distribution function and the one- and the two-body density matrices
BCS theory of superconductivity: the world's largest Madoff scheme?
Hirsch, J E
2009-01-01
The time-tested BCS theory of superconductivity is generally accepted to be the correct theory of conventional superconductivity by physicists and, by extension, by the world at large. In a different realm of human activity, until very recently Bernard Madoff's time-tested investment operation was generally accepted as true and legitimate in the financial world. Madoff's Ponzi scheme, where old investors were being paid off by funds contributed by new investors, was fundamentally flawed, yet was able to thrive for decades because of many vested interests. `Red flags' suggesting its illegitimacy were ignored. Here I suggest that the same is true of BCS theory. There are an increasing number of `red flags' that strongly suggest the possibility that BCS theory may be fundamentally flawed. For example, an ever-growing number of superconductors are being classified as `unconventional', not described by the conventional BCS theory and each requiring a different physical mechanism. In addition, I argue that BCS theo...
Umklapp scattering of pairs in BCS superconductivity theory
Zheng, X. H.; Walmsley, D. G.
2004-01-01
The BCS theory of superconductivity is extended to recognize pairing of electrons by both normal and umklapp scattering. Application of the variational approach shows that coexistence of normal and umklapp scattering frustrates superconductivity.
BCS theory of superconductivity: the world's largest Madoff scheme?
Hirsch, J. E.
2009-01-01
The time-tested BCS theory of superconductivity is generally accepted to be the correct theory of conventional superconductivity by physicists and, by extension, by the world at large. In a different realm of human activity, until very recently Bernard Madoff's time-tested investment operation was generally accepted as true and legitimate in the financial world. Madoff's Ponzi scheme, where old investors were being paid off by funds contributed by new investors, was fundamentally flawed, yet ...
A study of particle number fluctuation under BCS theory
2007-01-01
Particle number fluctuations in BCS theory are studied with the relativistic mean-field theory and the shell effects of particle number fluctuations are first discovered. By analyzing the relative errors of the particle number fluctuations, we find that the particle number fluctuations are relevant with the odd-even character. We later apply this method to the examination of the new shell structure, showing that N = 184 for the neutron is indeed a new closed shell.
Does the isotope effect of mercury support the BCS theory?
Huang, X. Q.
2011-01-01
In this paper, we reexamine the results of isotope effect experiments of the conventional monoatomic superconductor (Hg). It is shown clearly that the isotopic coefficients of mercury can be largely deviated from $\\alpha=0.5$, the standard value suggested by the phonon-mediated BCS pairing theory. According to the reported experimental results of various mercury isotopes, a giant isotope effect ($\\alpha=2.896$) is numerically found in the data. This study indicates that the validity of the co...
Degroote, Matthias; Henderson, Thomas M.; Zhao, Jinmo; Dukelsky, Jorge; Scuseria, Gustavo E.
2016-03-01
We present a similarity transformation theory based on a polynomial form of a particle-hole pair excitation operator. In the weakly correlated limit, this polynomial becomes an exponential, leading to coupled cluster doubles. In the opposite strongly correlated limit, the polynomial becomes an extended Bessel expansion and yields the projected BCS wave function. In between, we interpolate using a single parameter. The effective Hamiltonian is non-Hermitian and this polynomial similarity transformation theory follows the philosophy of traditional coupled cluster, left projecting the transformed Hamiltonian onto subspaces of the Hilbert space in which the wave function variance is forced to be zero. Similarly, the interpolation parameter is obtained through minimizing the next residual in the projective hierarchy. We rationalize and demonstrate how and why coupled cluster doubles is ill suited to the strongly correlated limit, whereas the Bessel expansion remains well behaved. The model provides accurate wave functions with energy errors that in its best variant are smaller than 1% across all interaction strengths. The numerical cost is polynomial in system size and the theory can be straightforwardly applied to any realistic Hamiltonian.
Effects of broadening on BCS theory in the presence of Van Hove singularities
There have been recent suggestions that high-Tc superconductivity can be understood in terms of conventional BCS theory if there is a logarithmic Van Hove singularity in the electron density of states near the Fermi energy as suggested by band theory. We consider the effects of broadening of the singularity on theories of this type. The broadening may be caused by inhomogeneities arising from doping or structural defects, electron inelastic scattering, and three-dimensional dispersion
Dynamical description of the fission process using the TD-BCS theory
Scamps, Guillaume, E-mail: scamps@nucl.phys.tohoku.ac.jp [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); Simenel, Cédric [Department of Nuclear Physics, Research School of Physics and Engineering Australian National University, Canberra, Australian Capital Territory 2601 (Australia); Lacroix, Denis [Institut de Physique Nucléaire, IN2P3-CNRS, Université Paris-Sud, F-91406 Orsay Cedex (France)
2015-10-15
The description of fission remains a challenge for nuclear microscopic theories. The time-dependent Hartree-Fock approach with BCS pairing is applied to study the last stage of the fission process. A good agreement is found for the one-body observables: the total kinetic energy and the average mass asymmetry. The non-physical dependence of two-body observables with the initial shape is discussed.
Dynamical description of the fission process using the TD-BCS theory
Scamps, Guillaume; Lacroix, Denis
2015-01-01
The description of fission remains a challenge for nuclear microscopic theories. The time-dependent Hartree-Fock approach with BCS pairing is applied to study the last stage of the fission process. A good agreement is found for the one-body observables: the total kinetic energy and the average mass asymmetry. The non-physical dependence of two-body observables with the initial shape is discussed.
Further test of new pairing scheme used in overhaul of BCS theory
Highlights: • Explanation of a new pairing scheme to overhaul BCS theory. • Prediction of superconductor properties from normal state resistivity. • Applications to Nb, Pb, Al, Ta, Mo, Ir and W, Tc between 9.5 and 0.012 K. • High accuracy compared with measured energy gap of Nb, Pb, Al and Ta. • Prediction of energy gap for Mo, Ir and W (so far not measured). - Abstract: A new electron pairing scheme, rectifying a fundamental flaw of the BCS theory, is tested extensively. It postulates that superconductivity arises solely from residual umklapp scattering when it is not in competition for the same destination electron states with normal scattering. It reconciles a long standing theoretical discrepancy in the strength of the electron–phonon interaction between the normal and superconductive states. The new scheme is exploited to calculate the superconductive electron–phonon spectral density, α2F(ν), entirely on the basis of normal state electrical resistivity. This leads to first principles superconductive properties (zero temperature energy gap and tunnelling conductance) in seven metals which turn out to be highly accurate when compared with known data; in other cases experimental verification is invited. The transition temperatures involved vary over almost three orders of magnitude: from 9.5 K for niobium to 0.012 K for tungsten
The (confinement) structure of Yang-Mills-theories within a Bose-BCS-theory
It is the purpose of this talk to report on a first attempt to apply (non-perturbative) techniques of many-body theory to a field-theory of the Yang-Mills-type. The procedure is in principle analogous to lattice calculations: In order to make the field-theoretical hamiltonian a well-behaved operator in the Fock-space, a phasespace-cutoff is assumed for the definition of the field operators. The coupling constant g then becomes a function of this cutoff which is fixed by some physical property like a glue-ball mass. (orig./HSI)
Conventional BCS, Unconventional BCS, and Non-BCS Hidden Dineutron Phases in Neutron Matter
Khodel, V A; Shaginyan, V R; Zverev, M V
2013-01-01
The nature of pairing correlations in neutron matter is re-examined. Working within the conventional approximation in which the $nn$ pairing interaction is provided by a realistic bare $nn$ potential fitted to scattering data, it is demonstrated that the standard BCS theory fails in regions of neutron number density where the pairing constant $\\lambda$, depending crucially on density, has a non-BCS negative sign. We are led to propose a non-BCS scenario for pairing phenomena in neutron matter that involves the formation of a hidden dineutron state. In low-density neutron matter where the pairing constant has the standard BCS sign, two phases organized by pairing correlations are possible and compete energetically: a conventional BCS phase and a dineutron phase. In dense neutron matter, where $\\lambda$ changes sign, only the dineutron phase survives and exists until the critical density for termination of pairing correlations is reached at approximately twice the neutron density in heavy atomic nuclei.
Deection of BCS pairing in neutral Fermi fluids via stokes scattering
Bruun, Georg Morten; Baym, Gordon
2004-01-01
A0530FFermion system and electron gas quantum statistical mechanics; A7420F-bcs-theory of superconductivity......A0530FFermion system and electron gas quantum statistical mechanics; A7420F-bcs-theory of superconductivity...
Relativistic BCS-BEC Crossover at Quark Level
Zhuang P.; Mao S; He L
2010-01-01
The non-relativistic G0G formalism of BCS-BEC crossover at ﬁnite temperature is extended to relativistic fermion systems. The theory recovers the BCS mean ﬁeld approximation at zero temperature and the non-relativistic results in a proper limit. For massive fermions, when the coupling strength increases, there exist two crossovers from the weak coupling BCS superﬂuid to the non-relativistic BEC state and then to the relativistic BEC state. For color superconductivity at moderate baryon ...
Relativistic BCS-BEC Crossover at Quark Level
Zhuang P.
2010-10-01
Full Text Available The non-relativistic G0G formalism of BCS-BEC crossover at ﬁnite temperature is extended to relativistic fermion systems. The theory recovers the BCS mean ﬁeld approximation at zero temperature and the non-relativistic results in a proper limit. For massive fermions, when the coupling strength increases, there exist two crossovers from the weak coupling BCS superﬂuid to the non-relativistic BEC state and then to the relativistic BEC state. For color superconductivity at moderate baryon density, the matter is in the BCS-BEC crossover region, and the behavior of the pseudogap is quite similar to that found in high temperature superconductors.
Full Text Available 1BCS 小麦 Bread Wheat ... Triticum aestivum Serine Carboxypeptidase Ii Chains A And B Name=Cbp2; Tri ... .Remington 1bcs 25 Peptide Aldehyde Complexes With Wheat ... Serine 1bcs 26 Carboxypeptidase Ii 1bcs 27to Be Pu ... Microbial Peptide Aldehyde Inhibitor 1bcs 21 CBP2_WHEAT :260,6|CBP2_WHEAT :418,266|PIR; A29639; A29639.|PDB; ...
Relativistic BCS-BEC Crossover at Finite Temperature and Its Application to Color Superconductivity
He, Lianyi; Zhuang, Pengfei
2007-01-01
The non-relativistic $G_0 G$ formalism of BCS-BEC crossover at finite temperature is extended to relativistic fermion systems. The uncondensed pairs contribute a pseudogap to the fermion excitations. The theory recovers the BCS mean field approximation at zero temperature and the non-relativistic results in a proper limit. For massive fermions, when the coupling strength increases, there exist two crossovers from the weak coupling BCS superfluid to the non-relativistic BEC state and then to t...
Commonality between BCS and TCS.
Shah, Vinod P; Rădulescu, Flavian Ştefan; Miron, Dalia Simona; Yacobi, Avraham
2016-07-25
Both biopharmaceutics classification system (BCS) and topical drug classification system (TCS) are based on sound scientific principles with the aim of providing biowaiver and reducing regulatory burden without lowering the quality requirements and standards of approval for the drug products. BCS is based on the solubility and permeability properties of the active pharmaceutical ingredient (API, or drug substance) whereas the TCS is based on the qualitative and quantitative composition of the dosage form and the in vitro release rate of the active ingredient as key decision tools. Both BCS and TCS take drug release and dissolution as their guiding principle for providing biowaiver, increasing the availability and affordability of safe and effective medicines to the consumers and at the same time maintaining the drug product quality. PMID:27208656
Energy Spectrum of a Degenerate Fermi Gas at the BEC-BCS Crossover
无
2007-01-01
A theoretical study of the BCS-BEC crossover is presented. Starting from a two-channel Boson-Fermion resonance model, the BCS-Bogoiubov mean-field method and the Green's function method are adopted. The result shows that we can end up with a BCS-type theory but with a composite order parameter. Calculation shows that the Bose condensate of BCS Cooper pairs is proportional to the molecular BEC of Bose molecules. The resonance superfluid phase is indicated by the energy spectrum with an obvious interpretation of the transition mechanism.
The BCS Model for General Pair Interaction
Hainzl, Christian; Hamza, Eman; Seiringer, Robert;
2008-01-01
The Bardeen-Cooper-Schrieffer (BCS) functional has recently received renewed attention as a description of fermionic gases interacting with local pairwise interactions. We present here a rigorous analysis of the BCS functional for general pair interaction potentials. For both zero and positive...... temperature, we show that the existence of a non-trivial solution of the nonlinear BCS gap equation is equivalent to the existence of a negative eigenvalue of a certain linear operator. From this we conclude the existence of a critical temperature below which the BCS pairing wave function does not vanish...
Structure of the number-projected BCS wave function
Dukelsky, J.; Pittel, S.; Esebbag, C.
2016-03-01
We study the structure of the number-projected BCS (PBCS) wave function in the particle-hole basis, displaying its similarities with coupled clusters theory (CCT). The analysis of PBCS together with several modifications suggested by the CCT wave function is carried out for the exactly solvable Richardson model involving a pure pairing Hamiltonian acting in a space of equally spaced, doubly degenerate levels. We point out the limitations of PBCS to describe the nonsuperconducting regime and suggest possible avenues for improvement.
The Solution to the BCS Gap Equation for Superconductivity and Its Temperature Dependence
Shuji Watanabe
2013-01-01
Full Text Available From the viewpoint of operator theory, we deal with the temperature dependence of the solution to the BCS gap equation for superconductivity. When the potential is a positive constant, the BCS gap equation reduces to the simple gap equation. We first show that there is a unique nonnegative solution to the simple gap equation, that it is continuous and strictly decreasing, and that it is of class with respect to the temperature. We next deal with the case where the potential is not a constant but a function. When the potential is not a constant, we give another proof of the existence and uniqueness of the solution to the BCS gap equation, and show how the solution varies with the temperature. We finally show that the solution to the BCS gap equation is indeed continuous with respect to both the temperature and the energy under a certain condition when the potential is not a constant.
Structure of the number projected BCS wave function
Dukelsky, J; Esebbag, C
2016-01-01
We study the structure of the number projected BCS (PBCS) wave function in the particle-hole basis, displaying its similarities with coupled clusters theory (CCT). The analysis of PBCS together with several modifications suggested by the CCT wave function is carried out for the exactly solvable Richardson model involving a pure pairing hamiltonian acting in a space of equally-spaced doubly-degenerate levels. We point out the limitations of PBCS to describe the non-superconducting regime and suggest possible avenues for improvement.
Perturbed bifurcations in the BCS gap equation
Spathis, P. N.; Sørensen, Mads Peter; Lazarides, Nickos
1992-01-01
The anisotropic BCS gap equation is applied to a tight-binding model of layered high-temperature superconductors. The possible solutions have s-, d-, and mixed s- and d-wave symmetries using nearest-neighbor intralayer singlet pairing interaction of the same strength in the x and y directions. The...
Evaluated body condition score (bcs) in puerperal period
Ilir Dova; Ana Kapaj; Enkeleda Ozuni; Imer Haziri
2013-01-01
BCS provides an important evaluation of the energy status of cows in puerperal period. This evaluation method provides a subjective indication of the fat cover on cows. To evaluate BCS is used a scoring point system based on the fat deposited in external part of the cow. In this study to evaluate BCS in cows in different farms we used 1 to 9 scoring system. The data shows different BCS classes between cows in different farms. All farms included in study shows that the BCS level is lower than ...
Resonant electronic Raman scattering: A BCS-like system
Rodrigues, Leonarde N.; Arantes, A.; Schüller, C.; Bell, M. J. V.; Anjos, V.
2016-05-01
In this paper we investigate the resonant intersubband Raman scattering of two-dimensional electron systems in GaAs-AlGaAs single quantum wells. Self-consistent calculations of the polarized and depolarized Raman cross sections show that the appearance of excitations at the unrenormalized single-particle energy are related to three factors: the extreme resonance regime, the existence of degeneracy in intersubband excitations of the electron gas, and, finally, degeneracy in the interactions between pairs of excitations. It is demonstrated that the physics that governs the problem is similar to the one that gives rise to the formation of the superconducting state in the BCS theory of normal metals. Comparison between experiment and theory shows an excellent agreement.
Evaluated body condition score (bcs in puerperal period
Ilir Dova
2013-09-01
Full Text Available BCS provides an important evaluation of the energy status of cows in puerperal period. This evaluation method provides a subjective indication of the fat cover on cows. To evaluate BCS is used a scoring point system based on the fat deposited in external part of the cow. In this study to evaluate BCS in cows in different farms we used 1 to 9 scoring system. The data shows different BCS classes between cows in different farms. All farms included in study shows that the BCS level is lower than the ideal BCS. This proves that all farms involved in the study have a level of feeding which is not optimal. In the period up to 2 months after calving is observed a gradual reduction of BCS in dairy cows.
Resonant Continuum in Extended RMF Plus BCS Approximation
CAO Li-Gang; MA Zhong-Yu
2004-01-01
The contribution of the resonant continuum to pairing correlations is investigated in the relativistic mean field theory plus Bardeen-Cooper-Schrieffer(BCS)approximation with a constant pairing strength.The resonance states with their widths in the continuum are considered explicitly.The numerical study is performed in an effective Lagrangian with the parameter set NLSH for neutron-rich nucleus 84Ni.The results show that the effect of the proper treatment of the resonant continuum on pairing correlations for nucleus close to neutron drip line is important.It is found that the problem of an unphysical particle gas could be overcome when the pairing correlation is performed by using the resonant states instead of the discretized states in the continuum.
The BCS appathon challenge at Greenwich
Arafa, Yasmine; Boldyreff, Cornelia; Malik, Asif; Wicks, Alan; Windall, Gillian
2016-01-01
The BCS Appathon set out to engage during one hour as many people as possible in the UK in programming an app for their mobile phones. It took place on the 9th June 2015, between 10.30 and 11.30, at a number of UK venues, one of which was the University of Greenwich. Many people now rely on their mobile phones and, daily, use a variety of apps on them, but few have any knowledge of how an app has been developed. The Appathon aimed not merely to give participants an understanding of app develo...
Highlights: ► We develop a perturbation expansion for the Bardeen–Cooper–Schrieffer Hamiltonian. ► We show that deviations from mean-field results are underextensive for relevant operators for any order of the perturbation theory. ► We discuss the relation between the BCS wave function and the exact wave function, which can be found by using Richardson approach. -- Abstract: The Bogoliubov approach to superconductivity provides a strong mathematical support to the wave function ansatz proposed by Bardeen, Cooper and Schrieffer (BCS). Indeed, this ansatz — with all pairs condensed into the same state — corresponds to the ground state of the Bogoliubov Hamiltonian. Yet, this Hamiltonian only is part of the BCS Hamiltonian. As a result, the BCS ansatz definitely differs from the BCS Hamiltonian ground state. This can be directly shown either through a perturbative approach starting from the Bogoliubov Hamiltonian, or better by analytically solving the BCS Schrödinger equation along Richardson–Gaudin exact procedure. Still, the BCS ansatz leads not only to the correct extensive part of the ground state energy for an arbitrary number of pairs in the energy layer where the potential acts — as recently obtained by solving Richardson–Gaudin equations analytically — but also to a few other physical quantities such as the electron distribution, as here shown. The present work also considers arbitrary filling of the potential layer and evidences the existence of a super dilute and a super dense regime of pairs, with a gap different from the usual gap. These regimes constitute the lower and upper limits of density-induced BEC–BCS cross-over in Cooper pair systems
BEC-BCS Crossover and the Liquid-Gas Phase Transition in Hot and Dense Nuclear Matter
Jin, Meng; Schuck, Peter
2010-01-01
The effect of nucleon-nucleon correlations in symmetric nuclear matter at finite temperature is studied beyond BCS theory. Starting from a Hartree-Fock description of nuclear matter with the Gogny effective interaction, we add correlations corresponding to the formation of preformed pairs and scattering states above the superfluid critical temperature within the in-medium T-matrix approach, which is analogous to the Nozieres-Schmitt-Rink theory. We calculate the critical temperature for a BEC superfluid of deuterons, of a BCS superfluid of nucleons, and in the crossover between these limits. The effect of the correlations on thermodynamic properties (equation of state, energy, entropy) and the liquid-gas phase transition is discussed. Our results show that nucleon-nucleon correlations beyond BCS play an important role for the properties of nuclear matter, especially in the low-density region.
Anderson, Brandon M.; Boyack, Rufus; Wu, Chien-Te; Levin, K.
2016-05-01
In this Rapid Communication we derive the full gauge-invariant electromagnetic response beyond the BCS level using the fermionic superfluid path integral. In the process we identify and redress a failure to satisfy the compressibility sum rule; this shortcoming is associated with the conventional path-integral formulation of BCS-level electrodynamics. The approach in this paper builds on an alternative saddle point scheme. At the mean field level, this leads to the well known gauge-invariant electrodynamics of BCS theory and to the satisfaction of the compressibility sum rule. Moreover, this scheme can be readily extended to address arbitrary higher order fluctuation theories (for example, at the Gaussian level.) At any level this approach will lead to a gauge invariant and compressibility sum rule consistent treatment of electrodynamics and thermodynamics.
Gravitationally bound BCS state as dark matter
Alexander, Stephon
2016-01-01
We explore the possibility that fermionic dark matter undergoes a BCS transition to form a superfluid. This requires an attractive interaction between fermions and we describe a possible source of this interaction induced by torsion. We describe the gravitating fermion system with the Bogoliubov-de Gennes formalism in the local density approximation. We solve the Poisson equation along with the equations for the density and gap energy of the fermions to find a self-gravitating, superfluid solution for dark matter halos. In order to produce halos the size of dwarf galaxies, we require a particle mass of $\\sim 200\\mathrm{eV}$. We find a maximum attractive coupling strength before the halo becomes unstable. If dark matter halos do have a superfluid component, this raises the possibility that they contain vortex lines which may be detectable via gravitational lensing.
The relation between the generalised Eshelby integral and the generalised BCS and DB models
Fan Tian-You; Fan Lei
2011-01-01
The generalised BCS dislocation group model and the generalised DB atomic cohesive force zone model have obtained the same results on nonlinear fracture study of some one-, two-and three-dimensional quasicrystals. This work reveals some inherent connection between the two models, and finds that their common basis is the generalised Eshelby integral based on the generalised Eshelby energy-momentum tensor for quasicrystals. Further applications of the theory in solving nonlinear fracture problems of the materials are also discussed.
Bussmann-Holder, Annette; Kohler, Jurgen; Whangbo, M.-H.; Bianconi, Antonio; Simon, Arndt
2016-01-01
The recent report of superconductivity under high pressure at the record transition temperature of Tc=203K in sulfur hydride has been identified as conventional in view of the observation of an isotope effect upon deuteration. Here it is demonstrated that conventional theories of superconductivity in the sense of BCS or Eliashberg formalisms can neither account for the observed values of Tc nor the pressure dependence of the isotope coefficient. The only way out of the dilemma is a multi-band...
Okazaki, K; Ito, Y.; Ota, Y; Kotani, Y.; Shimojima, T.; Kiss, T.; Watanabe, S; C.-T. Chen; S. Niitaka; Hanaguri, T; Takagi, H.; Chainani, A.; Shin, S.
2014-01-01
Conventional superconductivity follows Bardeen-Cooper-Schrieffer(BCS) theory of electrons-pairing in momentum-space, while superfluidity is the Bose-Einstein condensation(BEC) of atoms paired in real-space. These properties of solid metals and ultra-cold gases, respectively, are connected by the BCS-BEC crossover. Here we investigate the band dispersions in FeTe$_{0.6}$Se$_{0.4}$($T_c$ = 14.5 K $\\sim$ 1.2 meV) in an accessible range below and above the Fermi level($E_F$) using ultra-high reso...
A New First-Principles Calculation of Field-Dependent RF Surface Impedance of BCS Superconductor
Xiao, Binping [Brookhaven National Laboratory, Upton, New York (United States); Reece, Charles E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
2014-02-01
There is a need to understand the intrinsic limit of radiofrequency (RF) surface impedance that determines the performance of superconducting RF cavities in particle accelerators. Here we present a field-dependent derivation of Mattis-Bardeen theory of the RF surface impedance of BCS superconductors based on the shifted density of states resulting from coherently moving Cooper pairs. Our theoretical prediction of the effective BCS RF surface resistance (Rs) of niobium as a function of peak surface magnetic field amplitude agrees well with recently reported record low loss resonant cavity measurements from JLab and FNAL with carefully, yet differently, prepared niobium material. The surprising reduction in resistance with increasing field is explained to be an intrinsic effect.
THE BIOPHARMACEUTICAL CLASSIFICATION SYSTEM (BCS: PRESENT STATUS AND FUTURE PROSPECTIVES
Budhwaar Vikaas
2012-09-01
Full Text Available The Biopharmaceutical classification system (BCS was introduced By Amidon et al., (1995 as a method for classifying drug substances based on their dose/solubility ratio and intestinal permeability. It allows predicting the in vivo pharmacokinetic performance of drug products. The drug can be categorized into four classes of BCS, namely, High solubility high permeability, low solubility high permeability, High solubility low permeability and low solubility low permeability. An objective of BCS approach is to determine the equilibrium solubility of drug substances under physiological environment. The BCS helps in mathematically analyzing the kinetics and dynamics of drug in gastrointestinal tract (GIT for New Drug Applications (NDA and Abbreviated New Drug Applications (ANDA filings and biowaivers. This step reduces time in the new drug development process. Further it helps to decide when the dissolution rate is likely to be the rate determining step. It also helps in the prediction of potential of inactive ingredients in the dosage form to alter the dissolution / absorption of the drug. The present review, apart from giving a brief overview of BCS classification system, highlights these and some of the more recent applications of BCS classification system.
Detecting the BCS pairing amplitude via a sudden lattice ramp in a honeycomb lattice
Tiesinga, Eite; Nuske, Marlon; Mathey, Ludwig
2016-05-01
We determine the exact time evolution of an initial Bardeen-Cooper-Schrieffer (BCS) state of ultra-cold atoms in a hexagonal optical lattice. The dynamical evolution is triggered by ramping the lattice potential up, such that the interaction strength Uf is much larger than the hopping amplitude Jf. The quench initiates collective oscillations with frequency | Uf | /(2 π) in the momentum occupation numbers and imprints an oscillating phase with the same frequency on the order parameter Δ. The latter is not reproduced by treating the time evolution in mean-field theory. The momentum density-density or noise correlation functions oscillate at frequency | Uf | /(2 π) as well as its second harmonic. For a very deep lattice, with negligible tunneling energy, the oscillations of momentum occupation numbers are undamped. Non-zero tunneling after the quench leads to dephasing of the different momentum modes and a subsequent damping of the oscillations. This occurs even for a finite-temperature initial BCS state, but not for a non-interacting Fermi gas. We therefore propose to use this dephasing to detect a BCS state. Finally, we predict that the noise correlation functions in a honeycomb lattice will develop strong anti-correlations near the Dirac point. We acknowledge funding from the National Science Foundation.
A Number-Conserving Theory for Nuclear Pairing
Jia, L. Y.
2013-01-01
A microscopic theory for nuclear pairing is proposed through the generalized density matrix formalism. The analytical equations are as simple as that of the BCS theory, and could be solved within a similar computer time. The current theory conserves the exact particle number, and is valid at arbitrary pairing strength (including those below the BCS critical strength). These are the two main advantages over the conventional BCS theory. The theory is also of interests to other mesoscopic systems.
BCS Superconductivity in Quantum Critical Metals
She, Jian-Huang; Zaanen, Jan
2009-01-01
Departing from the assumption that pairing is induced by an retarded external 'bosonic glue', we reformulate the Bardeen-Cooper-Schrieffer theory of superconductivity as a scaling theory. Conventional superconductors correspond with the asymptotically free case but the theory can be effortlessly generalized to handle quantum critical metals. We find that superconducting Tc's are strongly enhanced in the latter when retardation is strong while the coupling is weak. It appears that this simple ...
BCS Theory of Hadronic Matter at High Densities
Bohr, Henrik; Panda, Prafulla K.; Providencia, Constanca;
2012-01-01
The equilibrium between the so-called 2SC and CFL phases of strange quark matter at high densities is investigated in the framework of a simple schematic model of the NJL type. Equal densities are assumed for quarks u, d and s. The 2SC phase is here described by a color-flavor symmetric state, in...
Superfluid nuclear matter in BCS theory and beyond
CAO Li-Gang; U. Lombardo; P. Schuck
2009-01-01
Medium polarization effects are studied for 1S0 pairing in nuclear matter within BHF approach.The screening potential is calculated in the RPA limit, suitably renormalized to cure the low density mechanical instability of nuclear matter. The self-energy corrections are consistently included resulting in a strong depletion of the Fermi surface. The self-energy effects always lead to a quenching of the gap, whereas it is almost completely compensated by the anti-screening effect in nuclear matter.
Hočevar, Mitja
2015-01-01
This BCs thesis deals with topics from graph theory. Ramsey theory in its most basic form deals with the problem of determining the minimal positive integer, such that for any edge-coloring of the complete graph of this size with a prescribed number of colors one can find a subgraph of predefined size all of whose edges are of the same colour. These minimal sizes are called Ramsey numbers. In this BCs thesis we present basic notions of graph theory needed to understand the basic theorem of...
Crossover between the dense electron-hole phase and the BCS excitonic phase in quantum dots
Second order perturbation theory and a Lipkin-Nogami scheme combined with an exact Monte Carlo projection after variation are applied to compute the ground-state energy of 6 ≤ N ≤ 210 electron-hole pairs confined in a parabolic two-dimensional quantum dot. The energy shows nice scaling properties as N or the confinement strength is varied. A crossover from the high-density electron-hole phase to the BCS excitonic phase is found at a density which is roughly four times the close-packing density of excitons. (author)
The relation between the generalised Eshelby integral and the generalised BCS and DB models
The generalised BCS dislocation group model and the generalised DB atomic cohesive force zone model have obtained the same results on nonlinear fracture study of some one-, two- and three-dimensional quasicrystals. This work reveals some inherent connection between the two models, and finds that their common basis is the generalised Eshelby integral based on the generalised Eshelby energy—momentum tensor for quasicrystals. Further applications of the theory in solving nonlinear fracture problems of the materials are also discussed. (condensed matter: structural, mechanical, and thermal properties)
Crossover between the Dense Electron-Hole Phase and the BCS Excitonic Phase in Quantum Dots
Rodriguez, Boris A.; Gonzalez, Augusto; Quiroga, Luis; Capote, Roberto; Rodriguez, Ferney
1998-01-01
Second order perturbation theory and a Lipkin-Nogami scheme combined with an exact Monte Carlo projection after variation are applied to compute the ground-state energy of $6\\le N\\le 210$ electron-hole pairs confined in a parabolic two-dimensional quantum dot. The energy shows nice scaling properties as N or the confinement strength is varied. A crossover from the high-density electron-hole phase to the BCS excitonic phase is found at a density which is roughly four times the close-packing de...
RMF+BCS Description of Some Traditional Neutron Magic Isotones
Saxena G; Singh D; Kaushik M
2014-01-01
The traditional neutron magic nuclei with N = 8, 20, 28, 50, 82 and 126, and those with neutron sub-magic number N = 40 are investigated within the relativistic mean-field plus BCS (RMF+BCS) approach. The results indicate appearance of new proton magic numbers as well as the disappearance of conventional magic numbers for nuclei with extreme isospin values. The calculated energies and densities do not indicate any tendency for the proton halo formations in any of the proton rich isotones due ...
The Hartree-Fock+BCS and generator coordinate methods
A new method to solve the Hartree-Fock+BCS equations with minimal symmetry requirements is described. It is shown that this method is very accurate, with reasonable computing time. The method can be generalized to study the nuclear dynamics within the generator coordinate method, and some applications examples are presented. (authors) 35 refs., 9 figs
Software testing an ISTQB-BCS certified tester foundation guide
Hambling, Brian; Samaroo, Angelina; Thompson, Geoff; Williams, Peter; Hambling, Brian
2015-01-01
This practical guide provides insight into software testing, explaining the basics of the testing process and how to perform effective tests. It provides an overview of different techniques and how to apply them. It is the best-selling official textbook of the ISTQB-BCS Certified Tester Foundation Level.
On the test of the modified BCS at finite temperature
Dang, N D; Dang, Nguyen Dinh; Arima, Akito
2005-01-01
The conclusions by Ponomarev and Vdovin [Phys. Rev. C {\\bf 72}, 034309 (2005)] are inadequate to judge the applicability of the modified BCS because they are based on the results obtained in the temperature region, where the testing systems are thermodynamically invalid.
Detection of BCS pairing in neutral fermi fluids via stokes scattering. The Hebel-slichter effect
Bruun, Georg Morten
2004-01-01
A0530F-Fermion-systems-and-electron-gas-quantum-statistical-mechanics;A7420F-BCS-theeory-of-superconductivity......A0530F-Fermion-systems-and-electron-gas-quantum-statistical-mechanics;A7420F-BCS-theeory-of-superconductivity...
BCS-Bose model of exotic superconductors: Generalized coherence length
Analytic expressions are derived for the root-mean-square (rms) radius of a pair of fermions in a BCS many-fermion state in one, two, and three dimensions, in terms of the BCS gap energy and the associated chemical potential. These expressions are valid for any coupling strength of any pair interaction model implying a momentum-independent gap energy. The latter holds, e.g., for an attractive δ pair potential examined in the one-dimensional (1D) case (whose N-fermion ground state can be determined exactly) or for the BCS (electron-phonon) model interaction in any dimension. Weak-coupling and/or high-density limits for the rms radius are identical in 1D, 2D, and 3D, and reduce to the familiar well-known Pippard result to within a factor of order unity. In contrast, strong-coupling and/or low-density limits coincide in 1D and 3D, but differ by a factor of order unity in the 2D limit, and in each case are essentially the size of a single, isolated pair. The 1D δ interaction McGuire-Yang-Gaudin many-fermion model is studied in detail. The interaction renormalization scheme of Miyake and of Randeria, Duan, and Shieh, and the BCS interaction model, both in 2D, are employed to analyze cuprate superconductor empirical results. Reasonable agreement between theoretical rms radii with experimental coherence lengths suggests that cuprates can be described moderately well as weakly coupled superconductors within the BCS-Bose formalism
Pairing in bulk nuclear matter beyond BCS
The influence of short-range correlations on the spectral distribution of neutrons is incorporated in the solution of the gap equation for the 3P2−3F2 coupled channel in pure neutron matter. This effect is studied for different realistic interactions including one based on chiral perturbation theory. The gap in this channel vanishes at all relevant densities due to the treatment of these correlations. We also consider the effect of long-range correlations by including polarization terms in addition to the bare interaction which allow the neutrons to exchange density and spin fluctuations governed by the strength of Landau parameters allowed to have reasonable values consistent with the available literature. Preliminary results indicate that reasonable values of these parameters do not generate a gap in the 3P2−3F2 coupled channel either for all three realistic interactions although the pairing interaction becomes slightly more attractive
Pairing in bulk nuclear matter beyond BCS
Ding, D; Dickhoff, W H; Dussan, H; Rios, A; Polls, A
2014-01-01
The influence of short-range correlations on the spectral distribution of neutrons is incorporated in the solution of the gap equation for the ${}^3P_2-{}^3F_2$ coupled channel in pure neutron matter. This effect is studied for different realistic interactions including one based on chiral perturbation theory. The gap in this channel vanishes at all relevant densities due to the treatment of these correlations. We also consider the effect of long-range correlations by including polarization terms in addition to the bare interaction which allow the neutrons to exchange density and spin fluctuations governed by the strength of Landau parameters allowed to have reasonable values consistent with the available literature. Preliminary results indicate that reasonable values of these parameters do not generate a gap in the ${}^3P_2-{}^3F_2$ coupled channel either for all three realistic interactions although the pairing interaction becomes slightly more attractive.
RMF+BCS Description of Some Traditional Neutron Magic Isotones
Saxena G.
2014-03-01
Full Text Available The traditional neutron magic nuclei with N = 8, 20, 28, 50, 82 and 126, and those with neutron sub-magic number N = 40 are investigated within the relativistic mean-field plus BCS (RMF+BCS approach. The results indicate appearance of new proton magic numbers as well as the disappearance of conventional magic numbers for nuclei with extreme isospin values. The calculated energies and densities do not indicate any tendency for the proton halo formations in any of the proton rich isotones due to Coulomb interaction and different single particle spectra. However, the potential barrier provided by the Coulomb interaction and that due to the centrifugal force may cause along delay in the actual decay of proton rich nucleus resulting the extended drip line.
RMF+BCS description of some traditional neutron magic isotones
The traditional neutron magic nuclei with N = 8, 20, 28, 50, 82 and 126, and those with neutron sub-magic number N = 40 are investigated within the relativistic mean-field plus BCS (RMF+BCS) approach. The results indicate appearance of new proton magic numbers as well as the disappearance of conventional magic numbers for nuclei with extreme isospin values. The calculated energies and densities do not indicate any tendency for the proton halo formations in any of the proton rich isotones due to Coulomb interaction and different single particle spectra. However, the potential barrier provided by the Coulomb interaction and that due to the centrifugal force may cause a long delay in the actual decay of proton rich nucleus resulting in the extended drip line. (authors)
Continuum discretised BCS approach for weakly bound nuclei
Lay, J. A.; Alonso, C. E.; Fortunato, L.; Vitturi, A.
2016-08-01
The Bardeen–Cooper–Schrieffer (BCS) formalism is extended by including the single-particle continuum in order to analyse the evolution of pairing in an isotopic chain from stability up to the drip-line. We propose a continuum discretised generalised BCS based on single-particle pseudostates (PS). These PS are generated from the diagonalisation of the single-particle Hamiltonian within a transformed harmonic oscillator basis. The consistency of the results versus the size of the basis is studied. The method is applied to neutron rich oxygen and carbon isotopes and compared with similar previous works and available experimental data. We make use of the flexibility of the proposed model in order to study the evolution of the occupation of the low-energy continuum when the system becomes weakly bound. We find an increasing influence of the non-resonant continuum as long as the Fermi level approaches the neutron separation threshold.
BCS @ 50: derivation of gap equations in different lattice geometries
We rigorously derive BCS gap equations for a square, triangular and a honeycomb lattice using a two-dimensional t-J model. The gap equations in all the three lattice geometries look usual, with band indices appearing and a minor modification in the separable pair potential for the (two band) honeycomb lattice. In each case, the gap equation is solved (self consistently with the number equation) at low densities assuming singlet pairing. (author)
BCS superconductivity of Dirac electrons in graphene layers
Kopnin, N. B.; Sonin, E. B.
2008-01-01
Possible superconductivity of electrons with the Dirac spectrum is analyzed using the BCS model. We calculate the critical temperature, the superconducting energy gap, and supercurrent as functions of the doping level and of the pairing interaction strength. Zero doping is characterized by existence of the quantum critical point such that the critical temperature vanishes below some finite value of the interaction strength. However, the critical temperature remains finite for any nonzero elec...
Thermodynamics of anisotropic-gap and multiband clean BCS superconductors
Mishonov, T.; Penev, E.
2002-01-01
The free energy, non-gradient terms of the Ginzburg-Landau expansion, and the jump of the specific heat of a multiband anisotropic-gap clean BCS superconductor are derived in the framework of a separable-kernel approximation. Results for a two-band superconductor, d-wave superconductor, and some recent models for MgB_2 are derived as special cases.
A two-dimensional Fermi gas in the BEC-BCS crossover
Ries, Martin Gerhard
2016-01-21
This thesis reports on the preparation of a 2D Fermi gas in the BEC-BCS crossover and the observation of the BKT transition into a quasi long-range ordered superfluid phase. The pair momentum distribution of the gas is probed by means of a matter-wave focusing technique which relies on time-of-flight evolution in a weak harmonic potential. This distribution holds the coherence properties of the gas. The quasi long-range ordered phase manifests itself as a sharp low-momentum peak. The temperature where it forms is identified as the transition temperature. By tuning the temperature and the interaction strength, the phase diagram of the 2D Fermi gas in the BEC-BCS crossover is mapped out. The phase coherence is investigated in a self-interference experiment. Furthermore, algebraic decay of correlations is observed in the trap average of the first order correlation function, which is obtained from the Fourier transform of the pair momentum distribution. This is in qualitative agreement with predictions of homogeneous theory for the superfluid phase in a 2D gas. The presented results provide a foundation for future experimental and theoretical studies of strongly correlated 2D Fermi gases. They might thus help to elucidate complex systems such as the electron gas in high-T{sub c} superconductors.
Proshin, Yurii N.; Khusainov, Marat M.; Minnullin, Arthur [Kazan Federal University, Kazan (Russian Federation)
2014-05-15
The theory of proximity effect, based on the boundary-value problem for the Eilenberger function in view of the in-plane Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) states, is proposed for thin asymmetrical structures FS, where F is a ferromagnetic metal and S is a BCS superconductor. The dependencies of critical temperature on an exchange field of the F metal, electronic correlations in the S and F metals, and thicknesses of layers F and S are calculated for four-layered FS systems and FS superlattices. A proposed classification of states includes up to 8 different states which are characterized by phase shifts between superconducting order parameters for neighboring S(F) layers and mutual orientation of magnetizations in adjacent F layers. For asymmetrical FS systems the solitary reentrant superconductivity is predicted. It is shown that the 2D-FFLO state prevails over the BCS one on the solitary peaks wings. The real candidate for observing predicted phenomena is Gd/La system, for which we found the sign and value of the constant of electronelectron interaction in gadolinium and explain the experimentally observed absence of the suppression of three dimensional superconductivity for symmetrical Gd/La superlattice. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
Body condition score (BCS and metabolic status of shelter dogs
I. Andrighetto
2010-04-01
Full Text Available A group of 147 shelter dogs were weighted and assigned a body condition score (BCS using a 9 point scale system, in order to evaluate the prevalence of obesity in the kennel. More than 60% of the animals showed a BCS³6 (overweight and obese and this condition was mainly attributed to an excess of carbohydrates and fat in the diet. In 67/147 dogs, a blood sample was drawn and the effects of BCS, age and time spent in the shelter were evaluated on biochemical parameters. Obese dogs showed significantly higher levels of triglycerides (P<0.01, while increasing BCS determined only an increasing non significant trend on cholesterol values. Age influenced creatinine (P<0.05 and the oldest dogs scoring BCS³6 registered significant higher NEFA (P<0.05 and CK (P=0.01 levels. Time spent in the shelter did not affect any parameter. The dogs’ metabolic condition reflects the need of taking more care of the quality of feed administered in the shelters to avoid the negative health effects caused by chronic obesity.
Alexandrov, A S, E-mail: a.s.alexandrov@lboro.ac.uk [Department of Physics, Loughborough University, Loughborough LE11 3TU (United Kingdom)
2011-03-01
It has been now over 20 years since the discovery of the first high temperature superconductor by Georg Bednorz and Alex Mueller in 1986 and yet, despite intensive effort, no universally accepted theory exists about the origin of high-temperature superconductivity. A controversial issue on whether the electron-phonon interaction (EPI) is crucial for high-temperature superconductivity or weak and inessential has been one of the most challenging problems of contemporary condensed matter physics. I briefly review our recent theoretical results, which in conjunction with a great number of experimental observations including isotope effects, angle-resolved photoemission (ARPES), pump-probe and tunnelling spectroscopies, normal state diamagnetism and magnetic quantum oscillations provide the definite answer to this fundamental question. The true origin of high-temperature superconductivity is found in a significant finite-range Froehlich EPI of nonadiabatic polaronic carriers which is beyond the conventional BCS-Migdal-Eliashberg approximation.
Cosmological BCS mechanism and the big bang singularity
We provide a novel mechanism that resolves the big bang singularity present in Friedman-Lemaitre-Robertson-Walker space-times without the need for ghost fields. Building on the fact that a four-fermion interaction arises in general relativity when fermions are covariantly coupled, we show that at early times the decrease in scale factor enhances the correlation between pairs of fermions. This enhancement leads to a BCS-like condensation of the fermions and opens a gap dynamically driving the Hubble parameter H to zero and results in a nonsingular bounce, at least in some special cases.
Absence of coherent peaks in a Z2 fractionalized BCS superconducting state
We explore a Z2 fractionalized Bardeen–Cooper–Schrieffer (BCS) superconducting state, which is a minimal extension of usual BCS framework. It is found that this state has similar thermal and transport properties, but its single-particle feature strongly deviates from the coherent quasiparticle behavior of the classic/conventional BCS superconducting state. The fingerprint of such Z2 BCS state is the absence of the BCS coherent peaks and instead a kink in the local density of state occurs, which in principle could be probed by scanning tunneling microscopy or point-contact spectroscopy experiments. The corresponding exactly soluble models that realize the desirable Z2 fractionalized BCS state are presented. In addition, we also study the extended t–U–J model by using Z2 slave-spin representation and find that the Z2 BCS state may exist when the paring structure is fully gapped or has nodes. The prototypical wave-function of such a Z2 BCS state is also proposed, which could be taken as trial wave-function in current numerical techniques. Furthermore, the pairing mechanism of Z2 BCS state is argued from both weak and strong coupling perspective. The present work may be helpful to further study the unconventional superconductivity and its relation to non-Fermi liquids
Tsume, Yasuhiro; Amidon, Gordon L
2010-08-01
The Biopharmaceutical Classification System (BCS) guidance issued by the FDA allows waivers for in vivo bioavailability and bioequivalence studies for immediate-release (IR) solid oral dosage forms only for BCS class I drugs. However, a number of drugs within BCS class III have been proposed to be eligible for biowaivers. The World Health Organization (WHO) has shortened the requisite dissolution time of BCS class III drugs on their Essential Medicine List (EML) from 30 to 15 min for extended biowaivers; however, the impact of the shorter dissolution time on AUC(0-inf) and C(max) is unknown. The objectives of this investigation were to assess the ability of gastrointestinal simulation software to predict the oral absorption of the BCS class I drugs propranolol and metoprolol and the BCS class III drugs cimetidine, atenolol, and amoxicillin, and to perform in silico bioequivalence studies to assess the feasibility of extending biowaivers to BCS class III drugs. The drug absorption from the gastrointestinal tract was predicted using physicochemical and pharmacokinetic properties of test drugs provided by GastroPlus (version 6.0). Virtual trials with a 200 mL dose volume at different drug release rates (T(85%) = 15 to 180 min) were performed to predict the oral absorption (C(max) and AUC(0-inf)) of the above drugs. Both BCS class I drugs satisfied bioequivalence with regard to the release rates up to 120 min. The results with BCS class III drugs demonstrated bioequivalence using the prolonged release rate, T(85%) = 45 or 60 min, indicating that the dissolution standard for bioequivalence is dependent on the intestinal membrane permeability and permeability profile throughout the gastrointestinal tract. The results of GastroPlus simulations indicate that the dissolution rate of BCS class III drugs could be prolonged to the point where dissolution, rather than permeability, would control the overall absorption. For BCS class III drugs with intestinal absorption patterns
Particle–hole duality, integrability, and Russian doll BCS model
Bork, L.V. [Center for Fundamental and Applied Research, N. L. Dukhov All-Russia Research Institute of Automatics, 127055 Moscow (Russian Federation); Institute for Theoretical and Experimental Physics, 117218 Moscow (Russian Federation); Pogosov, W.V., E-mail: walter.pogosov@gmail.com [Center for Fundamental and Applied Research, N. L. Dukhov All-Russia Research Institute of Automatics, 127055 Moscow (Russian Federation); Institute for Theoretical and Applied Electrodynamics, Russian Academy of Sciences, 125412 Moscow (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region 141700 (Russian Federation)
2015-08-15
We address a generalized Richardson model (Russian doll BCS model), which is characterized by the breaking of time-reversal symmetry. This model is known to be exactly solvable and integrable. We point out that the Russian doll BCS model, on the level of Hamiltonian, is also particle–hole symmetric. This implies that the same state can be expressed both in the particle and hole representations with two different sets of Bethe roots. We then derive exact relations between Bethe roots in the two representations, which can hardly be obtained staying on the level of Bethe equations. In a quasi-classical limit, similar identities for usual Richardson model, known from literature, are recovered from our results. We also show that these relations for Richardson roots take a remarkably simple form at half-filling and for a symmetric with respect to the middle of the interaction band distribution of one-body energy levels, since, in this special case, the rapidities in the particle and hole representations up to the translation satisfy the same system of equations.
Particle–hole duality, integrability, and Russian doll BCS model
We address a generalized Richardson model (Russian doll BCS model), which is characterized by the breaking of time-reversal symmetry. This model is known to be exactly solvable and integrable. We point out that the Russian doll BCS model, on the level of Hamiltonian, is also particle–hole symmetric. This implies that the same state can be expressed both in the particle and hole representations with two different sets of Bethe roots. We then derive exact relations between Bethe roots in the two representations, which can hardly be obtained staying on the level of Bethe equations. In a quasi-classical limit, similar identities for usual Richardson model, known from literature, are recovered from our results. We also show that these relations for Richardson roots take a remarkably simple form at half-filling and for a symmetric with respect to the middle of the interaction band distribution of one-body energy levels, since, in this special case, the rapidities in the particle and hole representations up to the translation satisfy the same system of equations
Particle-hole duality, integrability, and Russian doll BCS model
Bork, L. V.; Pogosov, W. V.
2015-08-01
We address a generalized Richardson model (Russian doll BCS model), which is characterized by the breaking of time-reversal symmetry. This model is known to be exactly solvable and integrable. We point out that the Russian doll BCS model, on the level of Hamiltonian, is also particle-hole symmetric. This implies that the same state can be expressed both in the particle and hole representations with two different sets of Bethe roots. We then derive exact relations between Bethe roots in the two representations, which can hardly be obtained staying on the level of Bethe equations. In a quasi-classical limit, similar identities for usual Richardson model, known from literature, are recovered from our results. We also show that these relations for Richardson roots take a remarkably simple form at half-filling and for a symmetric with respect to the middle of the interaction band distribution of one-body energy levels, since, in this special case, the rapidities in the particle and hole representations up to the translation satisfy the same system of equations.
We study the Coulomb-interaction induced spontaneous symmetry breaking of the excitonic insulator state in the two-dimensional extended Falicov-Kimball model. Using the variational cluster approximation, we evaluate the order parameter, single-particle excitation gap, momentum distribution functions, and anomalous Green's function as a function of U at zero temperature. We find that in the weak-to-intermediate couplinb regime, the Fermi surface is well-defined and the calculated results can be understood in the close correspondence with the BCS theory, whereas in the strong-coupling regime, the Fermi surface is ill-defined and the results are consistent with the picture of BEC.
More is Different:. 50 Years of Nuclear BCS
Broglia, R. A.
2013-01-01
At the basis of BCS theory, and associated symmetry breaking phenomena in gauge space, one finds Cooper pair binding. A major question in the nuclear case concerning this issue, regards the relative role played by the bare nucleon-nucleon force and by the interaction induced by the exchange of vibrations between members of Cooper pairs. The exotic nucleus 113Li8 in which two neutrons forming an extended halo, bind weakly to the 9Li core, provides an excellent testing ground to try to shed light on this issue. Theory finds that, in this case, the exchange of collective vibrations associated with the core and with the halo fields, provides an important fraction of the glue binding the pair. Inverse kinematics and active detector based experiments, combined with a quantitative description (based on absolute differential cross sections) of single Cooper pair tunneling, the specific probe of pairing in nuclei, which forces the virtual phonon into a real final state, have tested these predictions with positive results. The extension of structure and reaction studies to open shell (superfluid) nuclei (Sn-isotopes), displaying a strong alignment of quasispin in gauge space, and associated domain wall, as testified by pairing rotational bands excited in terms of single Cooper pair tunneling, provides an overall description of the data within experimental errors. This is also true in connection with pairing vibrations as observed in closed shell nuclei. Many of the concepts which are at the basis of the development associated with a quantitative treatment of the variety of phenomena associated with the spontaneous breaking of gauge symmetry in nuclei have been instrumental in connection with novel studies of soft matter, namely of protein evolution and protein folding. Although the route to these subjects and associated development does not necessarily imply the nuclear physics connection, such a connection has proven qualitatively and quantitatively inspiring. In particular
Dahan, Arik; Miller, Jonathan M; Amidon, Gordon L
2009-12-01
The Biopharmaceutics Classification System (BCS) categorizes drugs into one of four biopharmaceutical classes according to their water solubility and membrane permeability characteristics and broadly allows the prediction of the rate-limiting step in the intestinal absorption process following oral administration. Since its introduction in 1995, the BCS has generated remarkable impact on the global pharmaceutical sciences arena, in drug discovery, development, and regulation, and extensive validation/discussion/extension of the BCS is continuously published in the literature. The BCS has been effectively implanted by drug regulatory agencies around the world in setting bioavailability/bioequivalence standards for immediate-release (IR) oral drug product approval. In this review, we describe the BCS scientific framework and impact on regulatory practice of oral drug products and review the provisional BCS classification of the top drugs on the global market. The Biopharmaceutical Drug Disposition Classification System and its association with the BCS are discussed as well. One notable finding of the provisional BCS classification is that the clinical performance of the majority of approved IR oral drug products essential for human health can be assured with an in vitro dissolution test, rather than empirical in vivo human studies. PMID:19876745
BCS Superconductivity of Dirac Electrons in Graphene Layers
Kopnin, N. B.; Sonin, E. B.
2008-06-01
Possible superconductivity of electrons with the Dirac spectrum is analyzed using the BCS model. We calculate the critical temperature, the superconducting energy gap, and the supercurrent as functions of the doping level and of the pairing interaction strength. Zero doping is characterized by the existence of a quantum critical point such that the critical temperature vanishes below some finite value of the interaction strength. However, the critical temperature remains finite for any nonzero electron or hole doping level when the Fermi energy is shifted away from the Dirac point. As distinct from usual superconductors, the supercurrent density is not proportional to the number of electrons but is strongly decreased due to the presence of the Dirac point.
Teichmann, M
2007-09-15
We use a fermionic gas of Lithium-6 as a model system to study superfluidity. The limiting cases of superfluidity are Bose-Einstein condensation (BEC) and superconductivity, described by the theory by Bardeen, Cooper and Schrieffer (BCS). In Lithium-6 gases, we can explore the whole range between the two cases, known as the BEC-BCS crossover, using a Feshbach resonance. We study the change of the momentum distribution of the gas in this cross-over and compare to theoretical models. We also investigate the hydrodynamic expansion, characteristic for a superfluid gas. We observe a sudden change of the ellipticity of the gas close to the transition to the superfluid phase. Moreover, we localized heteronuclear Feshbach resonances between {sup 6}Li and {sup 7}Li. We are currently constructing a second generation of the experimental setup. An new laser system, based on high power laser diodes, was developed. Changes in the vacuum chamber, including a complete reconstruction of the Zeeman slower, have increased the atomic flux, allowing us to increase the repetition rate of our experiment. Modifications of the geometry of the magnetic traps lead to a higher number of trapped atoms. (author)
Bioavailability Enhancement Techniques for BCS Class II Drugs: A Review
Honey Kansara
2015-03-01
Full Text Available Traditionally, nearly 40% of the new chemical entities (NCEs identified by pharmaceutical industry screening programs have failed to be developed because of poor water-solubility, which makes their formulation difficult or even impossible. The solubility issues complicating the delivery of these new drugs also affect the delivery of many existing drugs. The various traditional and novel techniques that that can be used for solubility enhancement of BCS Class II drugs are briefly discussed in this article. The Traditional techniques that has been discussed in this article includes use of co-solvents, Hydrotropy, Micronization, change in dielectric constant of solvent, amorphousforms, chemical modification of drug, use of surfactants, inclusion complex, alteration of pH ofsolvent, use of hydrates or solvates, use of soluble prodrugs, application of ultrasonic waves, functional polymer technology, controlled precipitation technology, evaporative precipitation in aqueous solution, use of precipitation inhibitors, solvent deposition, precipitation, selective adsorption on insoluble carriers. Novel drug delivery technologies developed in recent years for solubility enhancement of insoluble drugs are size reduction technologies, lipid based delivery system, micellar technologies,porous micro particle technology. Solid Dispersion Technique and various types of solid dispersion systems have also been explained briefly.
We use a fermionic gas of Lithium-6 as a model system to study superfluidity. The limiting cases of superfluidity are Bose-Einstein condensation (BEC) and superconductivity, described by the theory by Bardeen, Cooper and Schrieffer (BCS). In Lithium-6 gases, we can explore the whole range between the two cases, known as the BEC-BCS crossover, using a Feshbach resonance. We study the change of the momentum distribution of the gas in this cross-over and compare to theoretical models. We also investigate the hydrodynamic expansion, characteristic for a superfluid gas. We observe a sudden change of the ellipticity of the gas close to the transition to the superfluid phase. Moreover, we localized heteronuclear Feshbach resonances between 6Li and 7Li. We are currently constructing a second generation of the experimental setup. An new laser system, based on high power laser diodes, was developed. Changes in the vacuum chamber, including a complete reconstruction of the Zeeman slower, have increased the atomic flux, allowing us to increase the repetition rate of our experiment. Modifications of the geometry of the magnetic traps lead to a higher number of trapped atoms. (author)
A PARAMETRIC STUDY OF BCS RF SURFACE IMPEDANCE WITH MAGNETIC FIELD USING THE XIAO CODE
Reece, Charles E. [JLAB; Xiao, Binping [JLAB, BNL
2013-09-01
A recent new analysis of field-dependent BCS rf surface impedance based on moving Cooper pairs has been presented.[1] Using this analysis coded in Mathematica TM, survey calculations have been completed which examine the sensitivities of this surface impedance to variation of the BCS material parameters and temperature. The results present a refined description of the "best theoretical" performance available to potential applications with corresponding materials.
Apo- and Cellopentaose-bound Structures of the Bacterial Cellulose Synthase Subunit BcsZ
Mazur, Olga; Zimmer, Jochen (UV)
2012-10-25
Cellulose, a very abundant extracellular polysaccharide, is synthesized in a finely tuned process that involves the activity of glycosyl-transferases and hydrolases. The cellulose microfibril consists of bundles of linear {beta}-1,4-glucan chains that are synthesized inside the cell; however, the mechanism by which these polymers traverse the cell membrane is currently unknown. In Gram-negative bacteria, the cellulose synthase complex forms a trans-envelope complex consisting of at least four subunits. Although three of these subunits account for the synthesis and translocation of the polysaccharide, the fourth subunit, BcsZ, is a periplasmic protein with endo-{beta}-1,4-glucanase activity. BcsZ belongs to family eight of glycosyl-hydrolases, and its activity is required for optimal synthesis and membrane translocation of cellulose. In this study we report two crystal structures of BcsZ from Escherichia coli. One structure shows the wild-type enzyme in its apo form, and the second structure is for a catalytically inactive mutant of BcsZ in complex with the substrate cellopentaose. The structures demonstrate that BcsZ adopts an ({alpha}/{alpha}){sub 6}-barrel fold and that it binds four glucan moieties of cellopentaose via highly conserved residues exclusively on the nonreducing side of its catalytic center. Thus, the BcsZ-cellopentaose structure most likely represents a posthydrolysis state in which the newly formed nonreducing end has already left the substrate binding pocket while the enzyme remains attached to the truncated polysaccharide chain. We further show that BcsZ efficiently degrades {beta}-1,4-glucans in in vitro cellulase assays with carboxymethyl-cellulose as substrate.
Inhomogeneous condensates in dilute nuclear matter and BCS-BEC crossovers
Stein, Martin; Huang, Xu-Guang; Clark, John W; Röpke, Gerd
2014-01-01
We report on recent progress in understanding pairing phenomena in low-density nuclear matter at small and moderate isospin asymmetry. A rich phase diagram has been found comprising various superfluid phases that include a homogeneous and phase-separated BEC phase of deuterons at low density and a homogeneous BCS phase, an inhomogeneous LOFF phase, and a phase-separated BCS phase at higher densities. The transition from the BEC phases to the BCS phases is characterized in terms of the evolution, from strong to weak coupling, of the condensate wavefunction and the second moment of its density distribution in $r$-space. We briefly discuss approaches to higher-order clustering in low-density nuclear matter.
Analysis of the superconductivity in perovskite oxides using three-square-well BCS formalism
G C Asomba; O Abah; O A Ogbuu; C M I Okoye
2015-12-01
Superconductivity in perovskite, BaKBiO, is studied in the Bardeen–Cooper–Schrieffer (BCS) model, with three-square-well potentials. Components of the new coupling are: the attractive acoustic phonon–electron, optical phonon–electron and repulsive Coulomb interactions. With these in the BCS pairing Hamiltonian, expressions for the superconducting transition temperature and isotope effect exponent are obtained. Results of our analysis are consistent with experiments. Contributions of interactions to system properties are exhibited and analysed. Acoustic phonon–electron and optical phonon–electron interactions have near-identical elevation of transition temperature, holding out possible explanations for high-. Contrastingly, optical phonon–electron and Coulomb couplings cause debilitation of isotope exponent, a possible explanation for low isotope exponent in the cuprates and other high- systems. It is found that BCS electron–phonon coupling appears synonymous with acoustic phonon–electron coupling.
Puji Astuti
2015-11-01
Full Text Available Body Condition Scoring (BCS is an estimation of the muscle and fat development of an animal. Thin ewes that are fighting to maintain their own body weight and low concentration of cortisol are not able to ovulate as ewes in a more desirable condition due to lack of oestradiol concentration. The aims of this research are to monitor the cortisol and oestradiol profile in Cross-bred ettawa does and to determine effect of BCS on the cortisol and oestradiol profile. Eight does were used in this research. These animals were devided equally into 2 groups based on Body Condition Scoring (BCS, namely BCS 2, which body weight range between 25-30 kgs as group I ( >n=4 and BCS 3 which consists of ettawa with body weight range between 33-40 kg as group II ( n=4 . All animals were synchronized using implant of CIDR and PGF2alpha. Blood from jugular vein were collected every 3 and 6 hours as soon as oestrus until 72 hours. Serum contained cortisol and oestradiol then assayed using ELISA
Phase fluctuations and BCS-LP crossover in 2D short coherence length superconductors
We study the effects of phase fluctuations in 2D short-coherence length superconductors on the basis of the extended Hubbard model with intersite attraction. In the Kosterlitz-Thouless scenario the critical temperatures for anisotropic pairings were determined and compared with the ones of BCS Hartree-Fock approximation. The Uemura-type plots, i.e. the critical temperature vs. zero temperature phase stiffness, were obtained for extended s-wave and dx2-y2 wave pairings. We also discuss the crossover from BCS to local pair superconductivity for d-wave pairing. (author)
Shell-model Monte Carlo simulations of the BCS-BEC crossover in few-fermion systems
Zinner, Nikolaj Thomas; Mølmer, Klaus; Özen, C.;
2009-01-01
strength, particle number, and temperature. The subtle question of renormalization in a finite model space is addressed and the convergence of our method and its applicability across the BCS-BEC crossover is discussed. Our findings indicate that very good quantitative results can be obtained on the BCS...
BCS Koolitus korraldab eesti keele kui teise keele õpetajatele tasuta arvutikoolitust
2003-01-01
28. mail 2003.a. kuulutati välja Integratsiooni Sihtasutuse ja Euroopa Liidu PHARE eesti keele õppe programmi konkursi võitja. Konkursi "Arvutiõpe - töölehtede ja õppeülesannete koostamise koolitus eesti keele kui teise keele õpetajatele" võitis BCS Koolitus
Fong, Sophia Y K; Liu, Mary; Wei, Hai; Löbenberg, Raimar; Kanfer, Isadore; Lee, Vincent H L; Amidon, Gordon L; Zuo, Zhong
2013-05-01
The Biopharmaceutical Classification System (BCS), which is a scientific approach to categorize active drug ingredient based on its solubility and intestinal permeability into one of the four classes, has been used to set the pharmaceutical quality standards for drug products in western society. However, it has received little attention in the area of Chinese herbal medicine (CHM). This is likely, in part, due to the presence of multiple active components as well as lack of standardization of CHM. In this report, we apply BCS classification to CHMs provisionally as a basis for establishing improved in vitro quality standards. Based on a top-200 drugs selling list in China, a total of 31 CHM products comprising 50 official active marker compounds (AMCs) were provisionally classified according to BCS. Information on AMC content and doses of these CHM products were retrieved from the Chinese Pharmacopoeia. BCS parameters including solubility and permeability of the AMCs were predicted in silico (ACD/Laboratories). A BCS classification of CHMs according to biopharmaceutical properties of their AMCs is demonstrated to be feasible in the current study and can be used to provide a minimum set of quality standards. Our provisional results showed that 44% of the included AMCs were classified as Class III (high solubility, low permeability), followed by Class II (26%), Class I (18%), and Class IV (12%). A similar trend was observed when CHMs were classified in accordance with the BCS class of AMCs. Most (45%) of the included CHMs were classified as Class III, followed by Class II (16%), Class I (10%), and Class IV (6%); whereas 23% of the CHMs were of mixed class due to the presence of multiple individual AMCs with different BCS classifications. Moreover, about 60% of the AMCs were classified as high-solubility compounds (Class I and Class III), suggesting an important role for an in vitro dissolution test in setting quality control standards ensuring consistent
Dong Hang; Ma Yong-Li
2009-01-01
Using quantum hydrodynamic approaches, we study the quantum pressure correction to the collective excitation spectrum of the interacting trapped superfluid Fermi gases in the BEC-BCS crossover. Based on a phenomenological equation of state, we derive hydrodynamic equations of the system in the whole BEC-BCS crossover regime. Beyond the Thomas-Fermi approximation, expressions of the frequency corrections of collective modes for both spherical and axial symmetric traps excited in the BEC-BCS crossover are given explicitly. The corrections of the eigenfrequencies due to the quantum pressure and their dependence on the inverse interaction strength. Anisotropic parameter and particle numbers of the condensate are discussed in detail.
Microscopic Derivation of Ginzburg-Landau Theory
Frank, Rupert; Hainzl, Christian; Seiringer, Robert;
2012-01-01
We give the first rigorous derivation of the celebrated Ginzburg-Landau (GL) theory, starting from the microscopic Bardeen-Cooper-Schrieffer (BCS) model. Close to the critical temperature, GL arises as an effective theory on the macroscopic scale. The relevant scaling limit is semiclassical in...
BEC-BCS crossover in a cold and magnetized two color NJL model
Duarte, Dyana C; Farias, R L S; Manso, Pedro H A; Ramos, Rudnei O; Scoccola, N N
2016-01-01
The BEC-BCS crossover for a NJL model with diquark interactions is studied in the presence of an external magnetic field. Particular attention is paid to different regularization schemes used in the literature. A thorough comparison of results is performed for the case of a cold and magnetized two-color NJL model. According to our results, the critical chemical potential for the BEC transition exhibits a clear inverse magnetic catalysis effect for magnetic fields in the range $ 1 \\lesssim eB/m_\\pi^2 \\lesssim 20 $. As for the BEC-BCS crossover, the corresponding critical chemical potential is very weakly sensitive to magnetic fields up to $eB \\sim 9\\ m_\\pi^2$, showing a much smaller inverse magnetic catalysis as compared to the BEC transition, and displays a strong magnetic catalysis from this point on.
Phase diagram of dilute nuclear matter: Unconventional pairing and the BCS-BEC crossover
We report on a comprehensive study of the phase structure of cold, dilute nuclear matter featuring a 3S1-3D1 condensate at non-zero isospin asymmetry, within wide ranges of temperatures and densities. We find a rich phase diagram comprising three superfluid phases, namely a LOFF phase, the ordinary BCS phase, and a heterogeneous, phase-separated BCS phase, with associated crossovers from the latter two phases to a homogeneous or phase-separated Bose-Einstein condensate of deuterons. The phase diagram contains two tri-critical points (one a Lifshitz point), which may degenerate into a single tetra-critical point for some degree of isospin asymmetry.
Einfluss von Hilfsstoffen auf die Bioverfügbarkeit von Substanzen der BCS Klasse III
Heinen, Christian
2014-01-01
In dieser Arbeit wurde der Effekt verschiedener Hilfsstoffe auf die Permeabilität von Substanzen der BCS Klasse III untersucht. Drei pharmazeutische Hilfsstoffe wurden hinsichtlich der Möglichkeit ihres Einsatzes als Permeationsverbesserer in Arzneistoffformulierungen untersucht. Außerdem wurde die Beteiligung von Gallensalzen an der Nahrungsmittel-Interaktion von Trospium untersucht.rnEs wurden Komplexe aus Trospium und λ-Carrageen hergestellt. Eine verbesserte Permeation, die höchstwahrsche...
BCS-BEC crossover induced by a synthetic non-Abelian gauge field
Vyasanakere, Jayantha P.; Zhang, Shizhong; Shenoy, Vijay B.
2011-07-01
We investigate the ground state of interacting spin-(1)/(2) fermions in three dimensions at a finite density (ρ˜kF3) in the presence of a uniform non-Abelian gauge field. The gauge-field configuration (GFC) described by a vector λ≡(λx,λy,λz), whose magnitude λ determines the gauge coupling strength, generates a generalized Rashba spin-orbit interaction. For a weak attractive interaction in the singlet channel described by a small negative scattering length (kF|as|≲1), the ground state in the absence of the gauge field (λ=0) is a BCS (Bardeen-Cooper-Schrieffer) superfluid with large overlapping pairs. With increasing gauge-coupling strength, a non-Abelian gauge field engenders a crossover of this BCS ground state to a BEC (Bose-Einstein condensate) of bosons even with a weak attractive interaction that fails to produce a two-body bound state in free vacuum (λ=0). For large gauge couplings (λ/kF≫1), the BEC attained is a condensate of bosons whose properties are solely determined by the Rashba gauge field (and not by the scattering length so long as it is nonzero)—we call these bosons “rashbons.” In the absence of interactions (as=0-), the shape of the Fermi surface of the system undergoes a topological transition at a critical gauge coupling λT. For high-symmetry GFCs we show that the crossover from the BCS superfluid to the rashbon BEC occurs in the regime of λ near λT. In the context of cold atomic systems, these results make an interesting suggestion of obtaining BCS-BEC crossover through a route other than tuning the interaction between the fermions.
Baek, Dae Heoun; Kwon, Seok-Joon; Hong, Seung-Pyo; Kwak, Mi-Sun; Lee, Mi-Hwa; Song, Jae Jun; Lee, Seung-Goo; Yoon, Ki-Hong; Sung, Moon-Hee
2003-01-01
A gene encoding a new thermostable d-stereospecific alanine amidase from the thermophile Brevibacillus borstelensis BCS-1 was cloned and sequenced. The molecular mass of the purified enzyme was estimated to be 199 kDa after gel filtration chromatography and about 30 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, indicating that the enzyme could be composed of a hexamer with identical subunits. The purified enzyme exhibited strong amidase activity towards d-amino acid-contai...
Fission barriers of odd-mass nuclei within the HF-BCS and HTDA approaches
Within two mean-field plus correlation descriptions (Hartree-Fock plus BCS or plus Highly Truncated Diagonalization Approaches) we study here some static properties of two odd-neutron nuclei (235U, 239Pu) from the ground-state deformation to the fission isomeric well, using three different Skyrme force parametrizations. A specific study of the polarization effects due to the account of relevant time-odd density functions is performed. (authors)
Description of Drip-Line Nuclei within Relativistic Mean-Field Plus BCS Approach
Yadav, H L; Toki, H
2004-01-01
Recently it has been demonstrated, considering Ni and Ca isotopes as prototypes, that the relativistic mean-field plus BCS (RMF+BCS) approach wherein the single particle continuum corresponding to the RMF is replaced by a set of discrete positive energy states for the calculation of pairing energy provides a good approximation to the full relativistic Hartree-Bogoliubov (RHB) description of the ground state properties of the drip-line neutron rich nuclei. The applicability of RMF+BCS is essentially due to the fact that the main contribution to the pairing correlations is provided by the low-lying resonant states. General validity of this approach is demonstrated by the detailed calculations for the ground state properties of the chains of isotopes of O, Ca, Ni, Zr, Sn and Pb nuclei. The TMA and NL-SH force parameter sets have been used for the effective mean-field Lagrangian. Comprehensive results for the two neutron separation energy, rms radii, single particle pairing gaps and pairing energies etc. are pres...
Atypical BCS-BEC crossover induced by quantum-size effects
Shanenko, A. A.; Croitoru, M. D.; Vagov, A. V.; Axt, V. M.; Perali, A.; Peeters, F. M.
2012-09-01
Quantum-size oscillations of the basic physical characteristics of a confined fermionic condensate are a well-known phenomenon. Its conventional understanding is based on the single-particle physics, whereby the oscillations follow variations in the single-particle density of states driven by the size quantization. Here we present a study of a cigar-shaped ultracold superfluid Fermi gas, which demonstrates an important many-body aspect of the quantum-size coherent effects, overlooked previously. The many-body physics is revealed here in the atypical crossover from the Bardeen-Cooper-Schrieffer (BCS) superfluid to the Bose-Einstein condensate (BEC) induced by the size quantization of the particle motion. The single-particle energy spectrum for the transverse dimensions is tightly bound, whereas for the longitudinal direction it resembles a quasi-free dispersion. This results in the formation of a series of single-particle subbands (shells) so that the aggregate fermionic condensate becomes a coherent mixture of subband condensates. Each time when the lower edge of a subband crosses the chemical potential, the BCS-BEC crossover is approached in this subband, and the aggregate condensate contains both BCS and BEC-like components.
Study of neutron magic drip-line nuclei within relativistic mean-field plus BCS approach
Encouraged by the success of relativistic mean-field plus BCS (RMF + BCS) approach for the description of the ground state properties of the chains of isotopes of proton magic nuclei with proton number Z = 8, 20, 28, 50 and 82 as well as those of proton sub-magic nuclei with Z = 40, we have further employed it, in an analogous manner, for a detailed calculations of the ground state properties of the neutron magic isotones with neutron number N = 8, 20, 28, 50, 82 and 126 as well as those of neutron sub-magic isotones with N = 40 using the TMA force parametrizations in order to explore low lying resonance and other exotic phenomenon near drip-lines. The results of these calculations for wave function, single particle pairing gaps etc. are presented here to demonstrate the general validity of our RMF + BCS approach. It is found that, in some of the proton-rich nuclei in the vicinity of the proton drip-line, the main contribution to the pairing correlations is provided by the low-lying resonant states, in addition to the contributions coming from the states close to the Fermi surface, which results extended proton drip-line for isotonic chain. (author)
Spin-polarized neutron matter: Critical unpairing and BCS-BEC precursor
Stein, Martin; Sedrakian, Armen; Huang, Xu-Guang; Clark, John W.
2016-01-01
We obtain the critical magnetic field required for complete destruction of S -wave pairing in neutron matter, thereby setting limits on the pairing and superfluidity of neutrons in the crust and outer core of magnetars. We find that for fields B ≥1017 G the neutron fluid is nonsuperfluid—if weaker spin 1 superfluidity does not intervene—a result with profound consequences for the thermal, rotational, and oscillatory behavior of magnetars. Because the dineutron is not bound in vacuum, cold dilute neutron matter cannot exhibit a proper BCS-BEC crossover. Nevertheless, owing to the strongly resonant behavior of the n n interaction at low densities, neutron matter shows a precursor of the BEC state, as manifested in Cooper-pair correlation lengths being comparable to the interparticle distance. We make a systematic quantitative study of this type of BCS-BEC crossover in the presence of neutron fluid spin polarization induced by an ultrastrong magnetic field. We evaluate the Cooper-pair wave function, quasiparticle occupation numbers, and quasiparticle spectra for densities and temperatures spanning the BCS-BEC crossover region. The phase diagram of spin-polarized neutron matter is constructed and explored at different polarizations.
BCS, Nambu-Jona-Lasinio, and Han-Nambu: A sketch of Nambu's works in 1960-1965
Fujikawa, Kazuo
2016-06-01
The years 1960-1965 were a remarkable period for Yoichiro Nambu. Starting with a reformulation of BCS theory with emphasis on gauge invariance, he recognized the realization of spontaneous chiral symmetry breaking in particle physics as evidenced by the Goldberger-Treiman relation. A concrete model of Nambu and Jona-Lasinio illustrated the essence of the Nambu-Goldstone theorem and the idea of soft pions. After the proposal of the quark model by Gell-Mann, he together with Han constructed an alternative model of integrally charged quarks with possible non-Abelian gluons. All these remarkable works were performed during the years 1960-1965. Here I briefly review those works following the original papers of Nambu chronologically, together with a brief introduction to a formulation of Noether's theorem and the Ward-Takahashi identities using path integrals. This article is mostly based on a lecture given at the Nambu Memorial Symposium held at Osaka City University in September 2015, where Nambu started his professional career.
BCS, Nambu-Jona-Lasinio, and Han-Nambu -- A sketch of Nambu's works in 1960-1965
Fujikawa, Kazuo
2016-01-01
The years of 1960-1965 were a remarkable period for Yoichiro Nambu. Starting with a reformulation of BCS theory with emphasis on gauge invariance, he recognized the realization of spontaneous chiral symmetry breaking in particle physics as is evidenced by the Goldberger-Treiman relation. A concrete model of Nambu and Jona-Lasinio illustrated the essence of the Nambu-Goldstone theorem and the idea of soft pions. After the proposal of the quark model by Gell-Mann, he together with Han constructed an alternative model of integrally charged quarks with possible non-Abelian gluons. All those remarkable works were performed during the years 1960-1965. Here I briefly review those works following the original papers of Nambu chronologically, together with a brief introduction to a formulation of Neother's theorem and Ward-Takahashi identities using path integrals. This article is mostly based on a lecture given at the Nambu Memorial Symposium held at Osaka City University in September 2015, where Nambu started his pr...
张宁; 平其能
2008-01-01
生物药剂分类系统是根据药物的溶解性和渗透性对药物进行分类的一种科学框架,目前FDA、WHO和EMEA都接受了这种分类概念.文中比较了不同管理当局对于生物药剂分类系统(BCS)的定义以及BCS在药品注册申报中支持生物等效免除的应用情况,综述了不同管理当局对于BCS的认识并提出了展望.
Hanai, R.; Littlewood, P. B.; Ohashi, Y.
2016-05-01
We theoretically investigate a Bose-condensed exciton gas out of equilibrium. Within the framework of the combined BCS-Leggett strong-coupling theory with the non-equilibrium Keldysh formalism, we show how the Bose-Einstein condensation (BEC) of excitons is suppressed to eventually disappear, when the system is in the non-equilibrium steady state. The supply of electrons and holes from the bath is shown to induce quasi-particle excitations, leading to the partial occupation of the upper branch of Bogoliubov single-particle excitation spectrum. We also discuss how this quasi-particle induction is related to the suppression of exciton BEC, as well as the stability of the steady state.
Turismo y Sustentabilidad en Pequeñas Localidades Localidades Costeras de Baja California Sur (BCS
Reyna Ibañez Pérez
2014-01-01
Full Text Available El fomento del turismo se realiza en sitios que, aunque pequeños, cuentan con atractivos naturales y culturales, tal es el caso de las zonas costeras. Tan solo en México, se estima que existen más de 1,100 comunidades que dependen directamente de dicha actividad, esta te ndencia se refleja, de igual manera, en pequeñas localidades costeras de Baja California Sur (BCS. En este sentido, el objetivo de este trabajo fue realizar un an álisis exploratorio que permitió detectar a las comunidades costeras de BCS, donde el turismo genera un aporte importante a su economía local, además , se buscó identificar la problemática general que éstas enfrentan. Para realizar dicho estudio se revisó literatura, se organizó información estadística y se elaboró un análisis Fortalezas, Oportunidades, Debilidades y Amenazas (FODA. Los resultad os apuntan a que, en BCS, existen más de 35 localidades ru rales vinculadas con dicha actividad que comparten como problemática la escasa in fraestructura y la carencia de medidas de control de la afluencia turística. La principal recomendación es desarrollar líneas de investigación que permitan aportar elementos para medir la sustentabilidad turística a nivel local y, co n base en ello, diseñar medidas para la adecuada conducción de tan importante actividad.
Thermodynamics of normal and BCS systems at the Fermi energy near the logarithmic singularity of DOS
The thermodynamics of Fermi particles in the band with the central logarithmic peak of DOS is discussed. This is accomplished if the absolute value of the difference of the Fermi energy and the energy of the peak of DOS is much smaller or much bigger than the temperature T, in units of energy. The T-dependence of the chemical potential is obtained, for s and p paired BCS systems, for low and subcritical T, as well as for normal systems. It leads, for superconducting systems, to a first order phase transition and to deviation of the Fermi surface caused by pairing
Importance of the single-particle continuum in BCS pairing with a pseudostate basis
Lay J. A.
2016-01-01
Full Text Available In a recent work [arXiv:1510.03185] the use of the Transformed Harmonic Oscillator (THO basis for the discretization of the singleparticle continuum into a Generalized Bardeen-Cooper-Schrieffer (BCS formalism was proposed for the description of weakly bound nuclei. We make use of the flexibility of this formalism to study the evolution of the pairing when the nucleus becomes more and more weakly bound. Specifically we focus on the evolution of the occupation of the different partial waves in 22O when the Fermi level approaches zero.
Josephson effect in fermionic superfluids across the BEC-BCS crossover.
Valtolina, Giacomo; Burchianti, Alessia; Amico, Andrea; Neri, Elettra; Xhani, Klejdja; Seman, Jorge Amin; Trombettoni, Andrea; Smerzi, Augusto; Zaccanti, Matteo; Inguscio, Massimo; Roati, Giacomo
2015-12-18
The Josephson effect is a macroscopic quantum phenomenon that reveals the broken symmetry associated with any superfluid state. Here we report on the observation of the Josephson effect between two fermionic superfluids coupled through a thin tunneling barrier. We show that the relative population and phase are canonically conjugate dynamical variables throughout the crossover from the molecular Bose-Einstein condensate (BEC) to the Bardeen-Cooper-Schrieffer (BCS) superfluid regime. For larger initial excitations from equilibrium, the dynamics of the superfluids become dissipative, which we ascribe to the propagation of vortices through the superfluid bulk. Our results highlight the robust nature of resonant superfluids. PMID:26680193
Turismo y Sustentabilidad en Pequeñas Localidades Localidades Costeras de Baja California Sur (BCS)
Reyna Ibañez Pérez
2014-01-01
El fomento del turismo se realiza en sitios que, aunque pequeños, cuentan con atractivos naturales y culturales, tal es el caso de las zonas costeras. Tan solo en México, se estima que existen más de 1,100 comunidades que dependen directamente de dicha actividad, esta te ndencia se refleja, de igual manera, en pequeñas localidades costeras de Baja California Sur (BCS). En este sentido, el objetivo de este trabajo fue realizar un an álisis exploratorio que permitió detectar a las comunidades c...
Collective Rabi oscillations and solitons in a time-dependent BCS pairing problem
Motivated by recent efforts to achieve cold fermions pairing, we study the nonadiabatic regime of the Bardeen-Cooper-Schrieffer state formation. After the interaction is turned on, at times shorter than the quasiparticle energy relaxation time, the system oscillates between the superfluid and normal state. The collective nonlinear evolution of the BCS-Bogoliubov amplitudes up, vp, along with the pairing function Δ, is shown to be an integrable dynamical problem which admits single soliton and soliton train solitons. We interpret the collective oscillations as Bloch precession of Anderson pseudospins, where each soliton causes a pseudospin 2π Rabi rotation
Study of two-proton radioactivity within the relativstic mean-field plus bcs approach
Singh, D.; Saxena, G.; Kaushik, M.; Yadav, H. L.; Toki, H.
2013-01-01
Encouraged by the success of RMF+BCS approach for the description of the ground state properties of the chains of isotopes of proton magic nuclei with proton number \\textit{Z}=8, 20, 28, 50 and 82 as well as those of proton sub-magic nuclei with \\textit{Z}=40, we have further employed it, in an analogous manner, for a detailed calculations of the ground state properties of the neutron magic isotones with neutron number \\textit{N} = 8, 20, 28, 50, 82 and 126 as well as those of neutron sub-mag...
Study of Neutron Magic Drip-Line Nuclei within Relativistic Mean Field plus BCS Approach
Saxena, G.; Singh, D.; Kaushik, M.; Yadav, H. L.; Toki, H.
2013-01-01
Encouraged by the success of RMF+BCS approach for the description of the ground state properties of the chains of isotopes of proton magic nuclei with proton number Z=8, 20, 28, 50 and 82 as well as those of proton sub-magic nuclei with Z=40, we have further employed it, in an analogous manner, for a detailed calculations of the ground state properties of the neutron magic isotones with neutron number N = 8, 20, 28, 50, 82 and 126 as well as those of neutron sub-magic isotones with N = 40 usi...
Spectral splits of neutrinos as a BCS-BEC crossover type phenomenon
Pehlivan, Y; Ghazanfari, N; Birol, S; Yüksel, H
2016-01-01
We show that the phenomenon of neutrino spectral split, which might be observed in the next galactic supernova neutrino signal, is analogous to the BCS-BEC crossover already observed in ultra cold atomic gas experiments. Although these two phenomena belong to two very different domains of physics, the propagation of neutrinos from highly interacting inner regions to the vacuum is reminiscent of the evolution of Cooper pairs between weak and strong interaction regimes. The Hamiltonians and the corresponding ground states undergo very similar transformations if one replaces the pair quasispin of the latter with the neutrino isospin of the former.
Propagation of sound and supersonic bright solitons in superfluid Fermi gases in BCS-BEC crossover
Wen, Wen; Shen, Shun-Qing; Huang, Guoxiang
2010-01-01
We investigate the linear and nonlinear sound propagations in a cigar-shaped superfluid Fermi gas with a large particle number. We first solve analytically the eigenvalue problem of linear collective excitations and provide explicit expressions of all eigenvalues and eigenfunctions, which are valid for all superfluid regimes in the Bardeen-Cooper-Schrieffer-Bose-Einstein condensation (BCS-BEC) crossover. The linear sound speed obtained agrees well with that of a recent experimental measurement. We then consider a weak nonlinear excitation and show that the time evolution of the excitation obeys a Korteweg de Vries equation. Different from the result obtained in quasi-one-dimensional case studied previously, where subsonic dark solitons are obtained via the balance between quantum pressure and nonlinear effect, we demonstrate that bright solitons with supersonic propagating velocity can be generated in the present three-dimensional system through the balance between a waveguidelike dispersion and the interparticle interaction. The supersonic bright solitons obtained display different physical properties in different superfluid regimes and hence can be used to characterize superfluid features of the BCS-BEC crossover.
Prediction of positive food effect: Bioavailability enhancement of BCS class II drugs.
Raman, Siddarth; Polli, James E
2016-06-15
High-throughput screening methods have increased the number of poorly water-soluble, highly permeable drug candidates. Many of these candidates have increased bioavailability when administered with food (i.e., exhibit a positive food effect). Food is known to impact drug bioavailability through a variety of mechanisms, including drug solubilization and prolonged gastric residence time. In vitro dissolution media that aim to mimic in vivo gastrointestinal (GI) conditions have been developed to lessen the need for fed human bioequivalence studies. The objective of this work was to develop an in vitro lipolysis model to predict positive food effect of three BCS Class II drugs (i.e., danazol, amiodarone and ivermectin) in previously developed lipolysis media. This in vitro lipolysis model was comparatively benchmarked against FeSSIF and FaSSIF media that were modified for an in vitro lipolysis approach, as FeSSIF and FaSSIF are widely used in in vitro dissolution studies. The in vitro lipolysis model accurately predicted the in vivo positive food effect for three model BCS class II drugs. The in vitro lipolysis model has potential use as a screening test of drug candidates in early development to assess positive food effect. PMID:27067239
Study of two-proton radioactivity within the relativstic mean-field plus bcs approach
Singh, D; Kaushik, M; Yadav, H L; Toki, H
2013-01-01
Encouraged by the success of RMF+BCS approach for the description of the ground state properties of the chains of isotopes of proton magic nuclei with proton number \\textit{Z}=8, 20, 28, 50 and 82 as well as those of proton sub-magic nuclei with \\textit{Z}=40, we have further employed it, in an analogous manner, for a detailed calculations of the ground state properties of the neutron magic isotones with neutron number \\textit{N} = 8, 20, 28, 50, 82 and 126 as well as those of neutron sub-magic isotones with \\textit{N} = 40 using the TMA force parameterizations in order to explore low lying resonance and other exotic phenomenon near drip-lines. The results of these calculations for wave-function, single particle pairing gaps etc. are presented here to demonstrate the general validity of our RMF+BCS approach. It is found that, in some of the proton-rich nuclei in the vicinity of the proton drip-line, the main contribution to the pairing correlations is provided by the low-lying resonant states, in addition to ...
The bioelectronic connectional system (BCS): a therapeutic target for non ionizing radiation.
Bistolfi, F
1990-01-01
Among cells and extracellular matrix have been demonstrated reciprocal interactions of oriented morphogenesis. As collagen fibers of the matrix, keratin filaments of desmosomes and the cytoskeleton elements are all piezoelectric substances, with particular biophysical characters, it is possible that these three classes of biostructures are the morphological expressions of a large and unitary cooperative system for coherent communication among cells, by means of piezoelectric interactions and photon/phonon transduction of electromagnetic signals, both endogenous and exogenous. The Author has proposed in 1989 to classify this morphofunctional complex as a bioelectronic connectional system (BCS), in which connective tissue is largely included, but the functions of which go well beyond its classical mechanical ones. The hypothesis is consistent both with the model of Welch and Berry (protonic energy continuum) and with the concept of bioplasma (Inyushin, Sedlak et al.). Physiology and pathology of BCS could also work as a starting point for experimental research aiming at inducing order in biostructures by means of non ionizing radiation. PMID:2263396
Spin-polarized neutron matter: critical unpairing and BCS-BEC precursor
Stein, Martin; Huang, Xu-Guang; Clark, John W
2015-01-01
We obtain the critical magnetic field required for complete destruction of $S$-wave pairing in neutron matter, thereby setting limits on the pairing and superfluidity of neutrons in the crust and outer core of magnetars. We find that for fields $B \\ge 10^{17}$ G the neutron fluid is non-superfluid, a result with profound consequences for the thermal, rotational, and oscillatory behavior of magnetars. Since the dineutron is not bound in vacuum, cold dilute neutron matter cannot exhibit a proper BCS-BEC crossover. Nevertheless, owing to the strongly resonant behavior of the $nn$ interaction at low densities, neutron matter shows a precursor of the BEC state, as manifested in Cooper-pair correlation lengths being comparable to the interparticle distance. We make a systematic quantitative study of this type of BCS-BEC crossover in the presence of neutron fluid spin-polarization induced by an ultra-strong magnetic field. We evaluate the Cooper pair wave-function, quasiparticle occupation numbers, and quasiparticle...
Proposed experimental test of the theory of hole superconductivity
Hirsch, J. E.
2016-06-01
The theory of hole superconductivity predicts that in the reversible transition between normal and superconducting phases in the presence of a magnetic field there is charge flow in direction perpendicular to the normal-superconductor phase boundary. In contrast, the conventional BCS-London theory of superconductivity predicts no such charge flow. Here we discuss an experiment to test these predictions.
Caro, Cary A.
2014-01-01
The Bowl Championship Series served as a collection of bowl games that were designed to crown the national champion in Division One football. The BCS created two classifications of institutions in Division football, those that were granted automatic access (AQ) to the post-season games, and those that were not (non-AQ). The BCS also generated…
Ortiz Prieto, Irais; Lorenzo Pulido, Cecilia [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)]. E-mail: cecilia.lorenzo@cfe.gob.mx
2009-07-15
Seismic monitoring at the Las Tres Virgenes, BCS, geothermal field started in 1992 with an analog station of vertical components detecting a large number of earthquakes of varying magnitudes. In February 1993, a seismic network was installed, composed of six digital stations DR-2000-with S-6000 and S-5000 sensors and three registration channels (N-S, E-W and vertical). This was the basis for the development of a program to correct arrival-time data for P and S waves due to instrument drift. From January to April 1994 and May to August 1995, based on the 170 seismic events recorded, a velocity model was proposed. From December 1995 to July 1996, seismic data were processed and interpreted, and zones of occurrence were determined for events according to magnitude and the predominant noise in the field. From September 2003 to December 2004, 10 seismic stations (permanent and temporary) were installed and monitored and it was concluded the most active fault system was El Volcan. From September to December 2004, production wells LV-4 and LV-13 were acid-stimulated and seismic monitoring during this period allowed for the definition of two important seismic zones, both related to the El Volcan fault system and to injection well LV-8. After reopening these production wells, it was concluded an increase in seismic activity had occurred. From May to August 2006, information was compiled from the seismic network and it was concluded El Partido had became the most active fault system. Presently the seismic network in this field is composed of one SARA station and four K2 units. The SARA station is telemetrically connected to the base station. [Spanish] En el campo geotermico de Las Tres Virgenes, BCS, el monitoreo sismico empezo a partir de 1992 con una sola estacion analogica de registro vertical, la cual detecto una gran cantidad de temblores de distintas magnitudes. En febrero de 1993 se instalo una red sismica con seis estaciones digitales DR-2000 con sensores S-6000 y S
Scattering length of composite bosons in the three-dimensional BCS-BEC crossover
Salasnich, L.; Bighin, G.
2015-03-01
We study the zero-temperature grand potential of a three-dimensional superfluid made of ultracold fermionic alkali-metal atoms in the BCS-BEC crossover. In particular, we analyze the zero-point energy of both fermionic single-particle excitations and bosonic collective excitations. The bosonic elementary excitations, which are crucial to obtain a reliable equation of state in the Bose-Einstein condensate regime, are obtained with a low-momentum expansion up to the forth order of the quadratic (Gaussian) action of the fluctuating pairing field. By performing a cutoff regularization and renormalization of Gaussian fluctuations, we find that the scattering length aB of composite bosons, bound states of fermionic pairs, is given by aB=(2 /3 ) aF , where aF is the scattering length of fermions.
Purely in silico BCS classification: science based quality standards for the world's drugs.
Dahan, Arik; Wolk, Omri; Kim, Young Hoon; Ramachandran, Chandrasekharan; Crippen, Gordon M; Takagi, Toshihide; Bermejo, Marival; Amidon, Gordon L
2013-11-01
BCS classification is a vital tool in the development of both generic and innovative drug products. The purpose of this work was to provisionally classify the world's top selling oral drugs according to the BCS, using in silico methods. Three different in silico methods were examined: the well-established group contribution (CLogP) and atom contribution (ALogP) methods, and a new method based solely on the molecular formula and element contribution (KLogP). Metoprolol was used as the benchmark for the low/high permeability class boundary. Solubility was estimated in silico using a thermodynamic equation that relies on the partition coefficient and melting point. The validity of each method was affirmed by comparison to reference data and literature. We then used each method to provisionally classify the orally administered, IR drug products found in the WHO Model list of Essential Medicines, and the top-selling oral drug products in the United States (US), Great Britain (GB), Spain (ES), Israel (IL), Japan (JP), and South Korea (KR). A combined list of 363 drugs was compiled from the various lists, and 257 drugs were classified using the different in silico permeability methods and literature solubility data, as well as BDDCS classification. Lastly, we calculated the solubility values for 185 drugs from the combined set using in silico approach. Permeability classification with the different in silico methods was correct for 69-72.4% of the 29 reference drugs with known human jejunal permeability, and for 84.6-92.9% of the 14 FDA reference drugs in the set. The correlations (r(2)) between experimental log P values of 154 drugs and their CLogP, ALogP and KLogP were 0.97, 0.82 and 0.71, respectively. The different in silico permeability methods produced comparable results: 30-34% of the US, GB, ES and IL top selling drugs were class 1, 27-36.4% were class 2, 22-25.5% were class 3, and 5.46-14% were class 4 drugs, while ∼8% could not be classified. The WHO list
Structure of a quantized vortex near the BCS-BEC crossover in an atomic Fermi gas
In order to clarify the structure of a singly quantized vortex in a superfluid fermion gas near the Feshbach resonance, we numerically solve the generalized Bogoliubov-de Gennes equation in the boson-fermion model. The superfluid gap, which contains contributions from both condensed fermion pairs and condensed bosons, is self-consistently determined, and the quasiparticle excitation levels bound in the vortex core are explicitly shown. We find that the boson condensate contributes to enhance the matter density depletion and the discreteness of localized quasiparticle spectrum inside the core. It is predicted that the matter density depletion and the discrete core levels are detectable in the vicinity of the BCS-Bose-Einstein condensation crossover point
Bose-Einstein to BCS crossover as a model for high-Tc cuprate superconductors
Crossover from Bose-Einstein (BE) to BCS condensation can be a guiding principle in understanding the evolution of high-Tc cuprate superconductors as a function of carrier doping. This picture is developed by combining two experimental results: (1) the ''universal correlations'' between Tc and ns/m* (superconducting carrier density/effective mass) found in μSR measurements of the magnetic field penetration depth λ and (2) the ''pseudo gap'' behavior observed in NMR, neutron scattering, dc- and optical conductivity, specific heat, and most-recently in angle-resolved photo-emission (ARPES) measurements. Here we provide a critical review of these experimental results and the relevant theoretical work in order to elucidate the essential features of this crossover picture and to discuss condensation mechanisms in the cuprates. (orig.)
BEC-BCS Crossover and the EoS of Strongly Interacting Systems
Ferrer, Efrain J
2013-01-01
We show that at sufficiently strong coupling, quarks form a BEC system that does not collapse into a pressureless gas at zero temperature only if the diquark-diquark repulsion is self-consistently taken into account. It is found that there is a critical value of the coupling constant of the diquark-diquark interaction beyond which the tendency at zero temperature of the strongly interacting diquark gas to condense into the system ground state with zero momentum is compensated by the repulsion between diquarks so keeping a positive pressure with no significant variation along the whole strongly interacting region. We discuss possible implications of the diquark-diquark interaction for the astrophysics of compact stars. Also we analyze the effect of a strong magnetic field for the BEC-BCS crossover.
RMF+BCS description of two-proton radioactivity in 2442Cr
Inspired by recent experimental studies of two-proton radioactivity in the light-medium mass region, relativistic mean-field plus state dependent BCS approach has been employed including deformation degree of freedom to study the ground state properties of selected even-Z nuclei in the region 20 ≤ Z ≤ 40. The results of our extensive calculations show that the nuclei 38Ti, 42Cr, 60Ge, 63,64Se, 68Kr, 72Sr and 76Zr satisfy the criteria Sp > 0 and S2p < 0. These nuclei are, therefore, expected to be the potential candidates for exhibiting the two-proton radioactivity in the region 20 ≤ Z ≤ 40
Present status of the theory of high Tc cuprates
Anderson, Philip W.
2005-01-01
The Gutzwiller-projected mean field theory, also called Plain Vanilla or RMFT, is explained and its successes and possible extensions in describing the phenomenology of the cuprate superconductors are discussed. Throughout we emphasize that while this is a Hartree-Fock-BCS based theory, it embodies fundamental differences from conventional perturbative many-body theory which may be characterized by calling it a theory of the doped Mott insulator.
Zur, Moran; Gasparini, Marisa; Wolk, Omri; Amidon, Gordon L; Dahan, Arik
2014-05-01
Although recognized as overly conservative, metoprolol is currently the common low/high BCS permeability class boundary reference compound, while labetalol was suggested as a potential alternative. The purpose of this study was to identify the various characteristics that the optimal marker should exhibit, and to investigate the suitability of labetalol as the permeability class reference drug. Labetalol's BCS solubility class was determined, and its physicochemical properties and intestinal permeability were thoroughly investigated, both in vitro and in vivo in rats, considering the complexity of the whole of the small intestine. Labetalol was found to be unequivocally a high-solubility compound. In the pH range throughout the small intestine (6.5-7.5), labetalol exhibited pH-dependent permeability, with higher permeability at higher pH values. While in vitro octanol-buffer partitioning (Log D) values of labetalol were significantly higher than those of metoprolol, the opposite was evident in the in vitro PAMPA permeability assay. The results of the in vivo perfusion studies in rats lay between the two contradictory in vitro studies; metoprolol was shown to have moderately higher rat intestinal permeability than labetalol. Theoretical distribution of the ionic species of the drugs was in corroboration with the experimental in vitro and the in vivo data. We propose three characteristics that the optimal permeability class reference drug should exhibit: (1) fraction dose absorbed in the range of 90%; (2) the optimal marker drug should be absorbed largely via passive transcellular permeability, with no/negligible carrier-mediated active intestinal transport (influx or efflux); and (3) the optimal marker drug should preferably be nonionizable. The data presented in this paper demonstrate that neither metoprolol nor labetalol can be regarded as optimal low/high-permeability class boundary standard. While metoprolol is too conservative due to its complete absorption
Jannin, Vincent; Chevrier, Stéphanie; Michenaud, Matthieu; Dumont, Camille; Belotti, Silvia; Chavant, Yann; Demarne, Frédéric
2015-11-10
Lipid-based formulations can be effective drug delivery systems for poorly water-soluble chemical entities, provided they are designed with careful selection of the excipients, based on their role in the delivery system and in relation to drug properties. The primary factor leading to increased bioavailability is the administration of the drug in a pre-dissolved state thereby avoiding the dissolution limiting step. All model drugs tested (piroxicam, curcumin and nifedipine) belong to the same chemical space--small BCS class II molecules with logP ranging from 2 to 3. These drugs, exhibiting low to medium logP, are not soluble in lipophilic lipid-based excipients (e.g., vegetable oils). Water-soluble and water-dispersible surfactants are able to dissolve the target dose of each drug in the dosage form and efficiently keep it in solution during dispersion. In vitro digestion testing was necessary to discriminate formulations and enable selection of the most robust one. For each molecule, the system with the best performance during dispersion/digestion tests did not comprise the surfactant which delivered the highest solvent capacity for the drug. This study demonstrates the potential of surfactant-based formulations - i.e., Type IV systems from the lipid formulation classification system - for this type of hydrophobic drug. PMID:26364710
Techniques used to Enhance Bioavailability of BCS Class II Drugs: A Review
Honey Kansara
2015-03-01
Full Text Available Traditionally, nearly 40% of the new chemical entities (NCEs identified by pharmaceutical industry screening programs have failed to be developed because of poor water-solubility, which makes their formulation difficult or even impossible. The solubility issues complicating the delivery of these new drugs also affect the delivery of many existing drugs. The various traditional and novel techniques that that can be used for solubility enhancement of BCS Class II drugs are briefly discussed in this article. The Traditional techniques that has been discussed in this article includes use of co-solvents, Hydrotropy, Micronization, change in dielectric constant of solvent, amorphous forms, chemical modification of drug, use of surfactants, inclusion complex, alteration of pH of solvent, use of hydrates or solvates, use of soluble prodrugs, application of ultrasonic waves, functional polymer technology, controlled precipitation technology, evaporative precipitation in aqueous solution, use of precipitation inhibitors, solvent deposition, precipitation, selective adsorption on insoluble carriers. Novel drug delivery technologies developed in recent years for solubility enhancement of insoluble drugs are size reduction technologies, lipid based delivery system, micellar technologies, porous micro particle technology. Solid Dispersion Technique and various types of solid dispersion systems have also been explained briefly.
Vortex line of spin-orbit coupled Fermi superfluid through BCS to BEC Crossover
Yao, Juan; Zhang, Shizhong
Superfluid Fermi gases with spin-orbit interaction provides a unique opportunity to investigate possible effects of strong interaction in a topological superfluid. It has been suggested that with addition of Rashba-type spin-orbit coupling, a two-component Fermi gas with strong s-wave interaction can become a topological superfluid with zero-energy bound state at the core of the vortex. In this talk, I discuss the evolution of vortex structure in a spin-orbit coupled Fermi gas through the BCS-BEC crossover within Bogoliubov-de Genne formalism. We find that the largest critical current occurs in the BEC side of the resonance, in contradiction to the usual crossover without spin-orbit coupling where it occurs at unitarity. Furthermore, we discuss the core structure of the vortex by calculating the spin and density distribution around the vortex. Department of Physics and Centre of Theoretical and Computational Physics, The University of Hong Kong, Hong Kong, China.
M.Sunitha Reddy
2011-11-01
Full Text Available The present work was aimed at the enhancement of solubility of Fenofibrate a BCS class II drug by Self Emulsifying Drug Delivery systems (SEDDS. The solubility of Fenofibrate in various excipients was determined. The excipients were screened for maximum solubility and compatibility. SEDDS formulations of Fenofibrate were developed using different Oils, Surfactants and Co-Surfactant combinations. Pseudoternary phase diagrams were drawn using Triplot software and by applying Pseudoternary phase diagrams, microemulsification area was evaluated.Formulations were screened based on visual observances and phase diagrams. Seven formulations were selected for further evaluations like stability, effect of dilution, freeze-thawing, emulsion droplet size and zeta potential. Among the seven formulations three were optimized and In-Vitro dissolution was performed. The dissolution rate of SEDDS was compared with plain Fenofibrate (API. The study confirmed that the solubility and dissolution rate of Fenofibrate were remarkably increased when compared to that of plain drug. Hence SEDDS formulations can be a potential alternative to traditional oral drug delivery systems of Fenofibrate to improve its bioavailability.
Webster, Tom
2002-09-18
Our overall purpose in writing this series of articles is to provide Federal energy managers some basic informational tools to assist their decision making process relative to energy management systems design, specification, procurement, and energy savings potential. Since Federal buildings rely on energy management systems more than their commercial counterparts, it is important for energy practitioners to have a high level of knowledge and understanding of these complex systems. This is the second article in a series and will focus on building control system (BCS) networking fundamentals and an assessment of current approaches to open communications protocols. This is important because networking is a complex subject and the networks form the basic infrastructure for energy management functions and for integrating a wide variety of OEM equipment into a complete EMCIS. The first article [1] covered enabling technologies for emerging energy management systems. Future topics will concentrate on more practical aspects including applications software, product offerings, networking strategies, and case studies of actual installations. Please refer to the first article for a more complete overview of the purpose and background for this series.
Application of BCS technology in pulverized coal furnace%BCS技术在煤粉炉上的应用
高瑞峰; 于现军
2015-01-01
BCS是应用于燃烧过程的通用优化控制技术，已成功应用于链条炉、 CFB锅炉、高炉热风炉、轧钢加热炉等多种炉型。在此基础上， BCS首次在某热电厂3台65 t／h煤粉炉上得到应用，并取得了良好的运行效果。%BCS is a sort of general optimization control technology for combustion process, which has been successfully applied to CFB boiler , chain boiler, hot stove for blast furnace, and reheating fur-nace for rolling etc.The optimization control system based on BCS was first put into use for 3 ×65t/h pulverized coal boiler and gets good results.
We investigate the two-dimensional attractive Hubbard model with quantum Monte Carlo techniques to reveal the crossover from a BCS-type superconductivity in the weak-coupling regime to a superconductivity properly described by a Bose-Einstein condensation (BEC) of local, preformed pairs. The crossover from BCS to BEC is particularly well exposed in the temperature dependence of both the spin susceptibility and the double occupancy, as well as by the appearance of a pseudogap in the density of states far above Tc. These features are also mirrored in the shape of the specific-heat peak around Tc, the separation of the temperature regimes where pair formation and their condensation occur, and in the transfer of spectral weight from the single-particle excitation branch to a pair band in the normal state. copyright 1996 The American Physical Society
Strong-coupling BCS superconductivity in noncentrosymmetric BaPtSi3: a low-temperature study
We report on measurements of the temperature dependence of the magnetic penetration depth of a high-quality sample of BaPtSi3 (Tc = 2.25 K). We observe a temperature-independent behaviour below T ≃ 0.2 Tc, which is firm evidence for the presence of an isotropic superconducting gap in this material. In the whole temperature range the superfluid density is described well by a strong-coupling Bardeen-Cooper-Schrieffer (BCS) model with an isotropic gap Δ0 ≈ 2kBTc. Our results provide further support for conventional BCS superconductivity in the nonmagnetic members of the noncentrosymmetric family of superconductors that crystallize with the BaNiSn3-type tetragonal structure. (paper)
Radwan, Asma; Amidon, Gordon L; Langguth, Peter
2012-10-01
A negative food effect, i.e. a decrease in bioavailability upon the co-administration of compounds together with food, has been attributed particularly with high solubility/low permeability compounds (BCS class III). Different mechanisms have been proposed including intestinal dilution leading to a lower concentration gradient across the intestinal wall as well as binding of the active pharmaceutical ingredient to food components in the intestine and thereby decreasing the fraction of the dose available for absorption. These mechanisms refer primarily to the compound and not to the dosage form. An increase in viscosity of the dissolution fluid will in particular affect the absorption of BCS type III compounds with preferential absorption in the upper small intestine if the API release is delayed from the dosage form. The present study demonstrated that the increase in viscosity of the dissolution medium, following ingestion of a solid meal, may drastically reduce disintegration and dissolution. For that purpose the viscosity of the standard FDA meal was determined and simulated by solutions of HPMC in buffer. As model formulations, three commercially available tablets containing trospium chloride, a BCS class III m-cholinoreceptor antagonist was used. Trospium chloride drug products have been described to undergo a negative food effect of more than 80% following ingestion with food. The tablets showed prolonged disintegration times and reduced dissolution rates in viscous media, which could be attributed to changes in the liquid penetration rates. The effect was particularly significant for film-coated tablets relative to uncoated dosage forms. The results show the necessity of considering media viscosity when designing in vitro models of drug release for BCS type III drug formulations. PMID:22782559
Systematic study of even-even nuclei with Hartree-Fock+BCS method using Skyrme SIII force
Tajima, Naoki; Takahara, Satoshi; Onishi, Naoki [Tokyo Univ. (Japan). Coll. of Arts and Sciences
1997-03-01
We have applied the Hartree-Fock+BCS method with Skyrme SIII force formulated in a three-dimensional Cartesian-mesh representation to even-even nuclei with 2 {<=} Z {<=} 114. We discuss the results concerning the atomic masses, the quadrupole (m=0, 2) and hexadecapole (m=0, 2, 4) deformations, the skin thicknesses, and the halo radii. We also discuss the energy difference between oblate and prolate solutions and the shape difference between protons and neutrons. (author)
Tsume, Yasuhiro; Langguth, Peter; Garcia-Arieta, Alfredo; Amidon, Gordon L.
2012-01-01
The FDA Biopharmaceutical Classification System guidance allows waivers for in vivo bioavailability and bioequivalence studies for immediate-release solid oral dosage forms only for BCS class I. Extensions of the in vivo biowaiver for a number of drugs in BCS Class III and BCS class II have been proposed, particularly, BCS class II weak acids. However, a discrepancy between the in vivo- BE results and in vitro- dissolution results for a BCS class II acids was recently observed. The objectives of this study were to determine the oral absorption of BCS class II weak acids via simulation software and to determine if the in vitro dissolution test with various dissolution media could be sufficient for in vitro bioequivalence studies of ibuprofen and ketoprofen as models of carboxylic acid drugs. The oral absorption of these BCS class II acids from the gastrointestinal tract was predicted by GastroPlus™. Ibuprofen did not satisfy the bioequivalence criteria at lower settings of intestinal pH=6.0. Further the experimental dissolution of ibuprofen tablets in the low concentration phosphate buffer at pH 6.0 (the average buffer capacity 2.2 mmol L-1/pH) was dramatically reduced compared to the dissolution in SIF (the average buffer capacity 12.6 mmol L -1/pH). Thus these predictions for oral absorption of BCS class II acids indicate that the absorption patterns largely depend on the intestinal pH and buffer strength and must be carefully considered for a bioequivalence test. Simulation software may be very useful tool to aid the selection of dissolution media that may be useful in setting an in vitro bioequivalence dissolution standard. PMID:22815122
Tsume, Yasuhiro; Langguth, Peter; Garcia-Arieta, Alfredo; Amidon, Gordon L
2012-10-01
The FDA Biopharmaceutical Classification System guidance allows waivers for in vivo bioavailability and bioequivalence studies for immediate-release solid oral dosage forms only for BCS class I. Extensions of the in vivo biowaiver for a number of drugs in BCS class III and BCS class II have been proposed, in particular, BCS class II weak acids. However, a discrepancy between the in vivo BE results and in vitro dissolution results for BCS class II acids was recently observed. The objectives of this study were to determine the oral absorption of BCS class II weak acids via simulation software and to determine if the in vitro dissolution test with various dissolution media could be sufficient for in vitro bioequivalence studies of ibuprofen and ketoprofen as models of carboxylic acid drugs. The oral absorption of these BCS class II acids from the gastrointestinal tract was predicted by GastroPlus™. Ibuprofen did not satisfy the bioequivalence criteria at lower settings of intestinal pH of 6.0. Further the experimental dissolution of ibuprofen tablets in a low concentration phosphate buffer at pH 6.0 (the average buffer capacity 2.2 mmol l (-1) /pH) was dramatically reduced compared with the dissolution in SIF (the average buffer capacity 12.6 mmol l (-1) /pH). Thus these predictions for the oral absorption of BCS class II acids indicate that the absorption patterns depend largely on the intestinal pH and buffer strength and must be considered carefully for a bioequivalence test. Simulation software may be a very useful tool to aid the selection of dissolution media that may be useful in setting an in vitro bioequivalence dissolution standard. PMID:22815122
Z. GERGÁCZ
2013-07-01
Full Text Available The aim of the study was to analyse the relationship between the body condition and the results of metabolic profile tests done in the milk (DIM of dairy cows in different days. Moreover, critical points in the early pre- and postpartum period were also analysed. In the experiment, blood and urine samples were taken from 1984 clinically healthy cows (from 49 large scale dairy farms in Hungary, selected randomly from various groups of cows with different physiological stage of lactation and gestation, 3-5 hours after the morning feeding. During the experiment body condition scoring (BCS was measured on 1-5 scale, as well. It was concluded, that the BCS (body condition score decreased from the 1st day of lactation (3.48 onwards till the 44th day (2.65 and slightly increased till the day 218 (2.89. The haemoglobin value and the glucose concentration in blood samples were ranging within the physiological range and followed the tendency of BCS and the relationship between them and DIM was (P<0.001. There was a close negative correlation between the NEFA (non-esterified-fatty-acid concentration in blood samples and BCS change and it was found that these values were significantly different (P<0.01 compared to the DIM. The aceto-acetic acid concentration exceeded the upper limit of the physiological range indicating hyperketonaemia at DIM 18. The AST (aspartate aminotransferase, liver-enzyme activity value exceeded the upper limit of physiological range and followed the tendency of BCS change . The urea concentration in the blood exceeded the upper limit of the physiological range in all cows. The NABE (net acid-base empty value in the urine samples indicated acid load in the first two groups of samples (pre-, and post calving. During factor analysis I could differentiate three group factors and one individual. The most important factor is the acid-based factor (with urine pH and NEBA. The results of the present study also confirm that the body
Dalsin, Molly C; Tale, Swapnil; Reineke, Theresa M
2014-02-10
Spray dried dispersions (SDDs), solid dispersions of polymer excipients and active pharmaceuticals, are important to the field of oral drug delivery for improving active stability, bioavailability, and efficacy. Herein, we examine the influence of solution-state polymer assemblies on amorphous spray-dried dispersion (SDD) performance with two BCS II model drugs, phenytoin and probucol. These drugs were spray dried with 4 model polymer excipients consisting of poly(ethylene-alt-propylene) (PEP), N,N,-dimethylacrylamide (DMA), or 2-methacrylamido glucopyranose (MAG): amphiphilic diblock ter- and copolymers, PEP-P(DMA-grad-MAG) and PEP-PDMA, and their respective hydrophilic analogues, P(DMA-grad-MAG) and PDMA. Selective and nonselective solvents for the hydrophilic block of the diblock ter- and copolymers were used to induce or repress solution-state assemblies prior to spray drying. Prespray dried solution-state assemblies of these four polymers were probed with dynamic light scattering (DLS) and showed differences in solution assembly size and structure (free polymer versus aggregates versus micelles). Solid-state structures of spray dried dispersions (SDDs) showed a single glass transition event implying a homogeneous mixture of drug/polymer. Crystallization temperatures and enthalpies indicated that the drugs interact mostly with the DMA-containing portions of the polymers. Scanning electron microscopy was used to determine SDD particle size and morphology for the various polymer-drug pairings. In vitro dissolution tests showed excellent performance for one system, spray-dried PEP-PDMA micelles with probucol. Dissolution structures were investigated through DLS to determine drug-polymer aggregates that lead to enhanced SDD performance. Forced aggregation of the polymer into regular micelle structures was found to be a critical factor to increase the dissolution rate and supersaturation maintenance of SDDs, and may be an attractive platform to exploit in excipient
Functional renormalization group approach to conventional theory of superfluidity and beyond
Fermionic functional renormalization group (FRG) is applied to describe the superfluid phase transition of the two-component fermionic system with attractive contact interaction. Connection between the fermionic FRG approach and the Bardeen-Cooper- Schrieffer (BCS) theory with its Gorkov and Melik-Barkhudarov (GMB) correction is made clear, and the FRG flow of the fermion self-energy is also studied to go beyond the BCS+GMB theory. The superfluid transition temperature and the associated chemical potential are calculated in the region of the negative scattering length using fermionic FRG.
Exact solutions of Nilsson mean-field plus various type of pairing interactions are briefly reviewed. Some even-odd mass differences and moment of inertia of low-lying states for rare earth and actinide nuclei calculated in nearest-orbit pairing and extended pairing models and comparison with the corresponding experimental data are shown. An exact boson mapping of the reduced BCS pairing Hamiltonian is reported. In the mapping, fermion pair operators are mapped exactly to the corresponding bosons. The image of the mapping results in a Bose-Hubbard model with level dependent hopping. (author)
Tajima, Hiroyuki; Hanai, Ryo; Ohashi, Yoji
2016-01-01
We theoretically investigate the uniform spin susceptibility χ in the superfluid phase of an ultracold Fermi gas in the region of the Bardeen-Cooper-Schrieffer-Bose-Einstein-condensate (BCS-BEC) crossover. In our previous paper [H. Tajima et al., Phys. Rev. A 89, 033617 (2014), 10.1103/PhysRevA.89.033617], including pairing fluctuations within an extended T -matrix approximation (ETMA), we showed that strong pairing fluctuations cause the so-called spin-gap phenomenon, where χ is anomalously suppressed even in the normal state near the superfluid phase transition temperature Tc. In this paper, we extend this work to the superfluid phase below Tc, to clarify how this many-body phenomenon is affected by the superfluid order. From the comparison of the ETMA χ with the Yosida function describing the spin susceptibility in a weak-coupling BCS superfluid, we identify the region where pairing fluctuations crucially affect this magnetic quantity below Tc in the phase diagram with respect to the strength of a pairing interaction and the temperature. This spin-gap regime is found to be consistent with the previous pseudogap regime determined from the pseudogapped density of states. We also compare our results with a recent experiment on a 6Li Fermi gas. Since the spin susceptibility is sensitive to the formation of spin-singlet preformed pairs, our results would be useful for the study of pseudogap physics in an ultracold Fermi gas on the viewpoint of the spin degrees of freedom.
We have used a newly presented self-consistent version of the BCS+RQRPA method for a nucleus-by-nucleus study of the double beta decay in the medium-heavy region. The results have been compared to the previously used approaches, namely the QRPA and the RQRPA approximations. We have shown that inclusion of the quasiparticle correlations at the BCS level reduces ground state correlations in the particle-particle channel of the proton-neutron interaction, resulting in the systematic reduction of the double beta decay matrix elements
Speed of Sound of a Spin-Balanced Fermi Gas with s- and d-Wave Pairings Across the BCS-BEC Evolution
Koinov, Zlatko; Mendoza, Rafael
2016-06-01
The authors of a recent paper (Phys Rev A 87:013613, 2013) argued that in fermionic systems with d-wave pairing the speed of sound is nonanalytic across the BCS-BEC crossover at the point where the chemical potential vanishes, regardless of the specific details of the interaction potential. On the contrary, the numerical results reported here suggest that the speed of sound across the BCS-BEC evolution of atomic Fermi gases with s- and d-wave pairings in two-dimensional square lattices is a smooth analytic function at the vanishing chemical potential.
BCS-like gap structure of HgBa{sub 2}CuO{sub 4+{delta}} tunnel junctions
Chen, J. [Argonne National Lab., IL (United States)]|[Yale Univ., New Haven, CT (United States); Zasadzinski, J.F.; Gray, K.E.; Wagner, J.L.; Hinks, D.G. [Argonne National Lab., IL (United States); Kouznetsov, K.; Coffey, L. [Illinois Inst. of Tech., Chicago, IL (United States)
1994-12-01
The authors report point-contact tunneling into polycrystalline HgBa{sub 2}CuO{sub 4+{delta}} superconductors with a T{sub c} onset of 97 K using a superconducting Nb counterelectrode. These SIS tunnel junctions are of unusually high quality for cuprate superconductors, exhibiting low and flat sub-gap conductances and sharp conductance peaks as expected from a BCS density of states. These features are obtained reproducibly and are consistent with earlier published SIN results using an Au counterelectrode. Use of experimental data to simulate the performance of a quasiparticle mixer indicates that HgBa{sub 2}CuO{sub 4+{delta}} may be suitable for use in low noise heterodyne receivers operating at a few THz.
We study ultracold neutral fermion superfluids in the presence of fictitious magnetic fields, as well as charged fermion superfluids in the presence of real magnetic fields. Charged fermion superfluids undergo a phase transition from type-I to type-II superfluidity, where the magnetic properties of the superfluid change from being a perfect diamagnet without vortices to a partial diamagnet with the emergence of the Abrikosov vortex lattice. The transition from type-I to type-II superfluidity is tuned by changing the scattering parameter (interaction) for fixed density. We also find that neutral fermion superfluids such as 6Li and 40K are extreme type-II superfluids and are more robust to the penetration of a fictitious magnetic field in the BCS-BEC crossover region near unitarity, where the critical fictitious magnetic field reaches a maximum as a function of the scattering parameter (interaction).
Zhang XW
2014-11-01
Full Text Available Xingwang Zhang,* Guijiang Chen,* Tianpeng Zhang, Zhiguo Ma, Baojian WuDivision of Pharmaceutics, College of Pharmacy, Jinan University, Guangzhou, People’s Republic of China*These authors contributed equally to this workAbstract: Lipid nanocarriers are becoming a versatile platform for oral delivery of lipophilic drugs. In this article, we aimed to explore the gastrointestinal behaviors of lipid nanoparticles and the effect of PEGylation on oral absorption of fenofibrate (FN, a Biopharmaceutics Classification System (BCS II model drug. FN-loaded PEGylated lipid nanoparticles (FN-PLNs were prepared by the solvent-diffusion method and characterized by particle size distribution, morphology, Fourier transform infrared spectroscopy, and drug release. Lipolytic experiments were performed to assess the resistance of lipid nanoparticles against pancreatic lipase. Pharmacokinetics was evaluated in rats after oral administration of FN preparations. The obtained FN-PLNs were 186.7 nm in size with an entrapment efficiency of >95%. Compared to conventional lipid nanoparticles, PLNs exhibited slower drug release in the lipase-containing medium, strikingly reduced mucin binding, and suppressed lipolysis in vitro. Further, oral absorption of FN was significantly enhanced using PLNs with relative bioavailability of 123.9% and 157.0% to conventional lipid nanoparticles and a commercial formulation (Lipanthyl®, respectively. It was demonstrated that reduced mucin trapping, suppressed lipolysis, and/or improved mucosal permeability were responsible for increased oral absorption. These results facilitated a better understanding of the in vivo fate of lipid nanoparticles, and suggested the potential of PLNs as oral carriers of BCS II drugs.Keywords: fenofibrate, lipid nanoparticles, PEGylation, oral bioavailability, absorption mechanism
Kujawa-Cichy, Agnieszka
2013-01-01
The aim of this Ph.D. thesis was to investigate superconducting properties in the presence of Zeeman magnetic field in systems with local fermion pairing on the lattice. The study also concerned the evolution from the weak coupling (BCS-like) limit to the strong coupling limit of tightly bound local pairs (BEC) with increasing attraction, both in the ground state and at finite temperatures, within the spin-polarized extended Hubbard model. The analysis was also extended to the case of spin dependent hopping integrals (mass imbalance), with special attention paid to the BCS-BEC crossover physics in the ground state. The methods used included: the mean field approximation (BCS-Stoner type) and the estimation of the phase coherence temperature within the Kosterlitz-Thouless (KT) scenario in two dimensions. The BCS-BEC crossover was also analyzed in three dimensions, at finite temperatures, within the spin polarized Attractive Hubbard Model (AHM), going beyond the mean field approximation. In this case, the criti...
Vortex structures and zero-energy states in the BCS-to-BEC evolution of p-wave resonant Fermi gases
Multiply quantized vortices in the BCS-to-BEC (Bose-Einstein condensation) evolution of p-wave resonant Fermi gases are investigated theoretically. The vortex structure and the low-energy quasiparticle states are discussed, based on the self-consistent calculations of the Bogoliubov-de Gennes and gap equations. We reveal the direct relation between the macroscopic structure of vortices, such as particle densities, and the low-lying quasiparticle state. In addition, the net angular momentum for multiply quantized vortices with a vorticity κ is found to be expressed by a simple equation, which reflects the chirality of the Cooper pairing. Hence, the observation of the particle density depletion and the measurement of the angular momentum will provide the information on the core-bound state and p-wave superfluidity. Moreover, the details on the zero energy Majorana state are discussed in the vicinity of the BCS-to-BEC evolution. It is demonstrated numerically that the zero energy Majorana state appears in the weak coupling BCS limit only when the vortex winding number is odd. The κ branches of the core-bound states for a vortex state with vorticity κ exist; however, only one of them can be the zero energy. This zero energy state vanishes at the BCS-BEC topological phase transition because of interference between the core-bound and edge-bound states.
Calculations of the (E,JΠ) spectra and the electromagnetic properties (fe,Q,BEZ,BM1) are made for Ni odd isotopes, and odd isotones with N=82, using the Shell Model (SM), the usual BCS approximation (one and three quasiparticles), blocking BCS (BBCS) and projected BCS (PBCS). The importance of the five quasiparticle correlations and of the correlation introduced in BCS are examined in detail. The collective degrees of freedom of the core are introduced through the quasiparticle-cluster-vibrator coupling (QPCVC), so that this formalism permits as well the inclusion of blocking as the projection in number of particles in the cluster of one and three quasiparticles. Comparative calculations are made between the version with blocking (BQPCV) and with projection (PQPCV) for spectra and electromagnetic properties of Zn old isotopes. The projected version is applied to the cesium isotopes in the description of the 5/2+ states generated by the anomalous coupling. In all examined cases, the comparison with the available experimental data is also shown. (L.C.)
Shah, Vinod P.; Amidon, Gordon L.
2014-01-01
The Biopharmaceutics Classification System (BCS) has become widely accepted today in the academic, industrial, and regulatory world. While the initial application of the BCS was to regulatory science bioequivalence (BE) issues and related implications, it has come to be utilized widely by the pharmaceutical industry in drug discovery and development as well. This brief manuscript will relate the story of the BCS development. While much of the ground work for the BCS goes back to the pharmacok...
Superconductivity theory applied to the periodic table of the elements
The modern theory of superconductivity, based upon the BCS to Bose-Einstein transition, is applied to the periodic table of the elements, in order to isolate the essential features of high temperature superconductivity and to predict its occurrence within the periodic table. It is predicted that Sodium-Ammonia, Sodium Zinc Phosphide and Bismuth (I) Iodide are promising materials for experimental explorations of high temperature superconductivity
Superconductivity theory applied to the periodic table of the elements
Elifritz, Thomas Lee
1995-01-01
The modern theory of superconductivity, based upon the BCS to Bose-Einstein transition is applied to the periodic table of the elements, in order to isolate the essential features of of high temperature superconductivity and to predict its occurrence with the periodic table. It is predicted that Sodium-Ammonia, Sodium Zinc Phosphide and Bismuth (I) Iodide are promising materials for experimental explorations of high temperature superconductivity.
Superconductivity theory applied to the periodic table of the elements
Elifritz, T.L. [Information Corporation, Madison, WI (United States)
1994-12-31
The modern theory of superconductivity, based upon the BCS to Bose-Einstein transition, is applied to the periodic table of the elements, in order to isolate the essential features of high temperature superconductivity and to predict its occurrence within the periodic table. It is predicted that Sodium-Ammonia, Sodium Zinc Phosphide and Bismuth (I) Iodide are promising materials for experimental explorations of high temperature superconductivity.
Chiral random matrix theory for two-color QCD at high density
Kanazawa, Takuya; Wettig, Tilo; Yamamoto, Naoki
2009-01-01
We identify a non-Hermitian chiral random matrix theory that corresponds to two-color QCD at high density. We show that the partition function of the random matrix theory coincides with the partition function of the finite-volume effective theory at high density, and that the Leutwyler-Smilga-type spectral sum rules of the random matrix theory are identical to those derived from the effective theory. The microscopic Dirac spectrum of the theory is governed by the BCS gap, rather than the conv...
Renormalization group theory impact on experimental magnetism
Köbler, Ulrich
2010-01-01
Spin wave theory of magnetism and BCS theory of superconductivity are typical theories of the time before renormalization group (RG) theory. The two theories consider atomistic interactions only and ignore the energy degrees of freedom of the continuous (infinite) solid. Since the pioneering work of Kenneth G. Wilson (Nobel Prize of physics in 1982) we know that the continuous solid is characterized by a particular symmetry: invariance with respect to transformations of the length scale. Associated with this symmetry are particular field particles with characteristic excitation spectra. In diamagnetic solids these are the well known Debye bosons. This book reviews experimental work on solid state physics of the last five decades and shows in a phenomenological way that the dynamics of ordered magnets and conventional superconductors is controlled by the field particles of the infinite solid and not by magnons and Cooper pairs, respectively. In the case of ordered magnets the relevant field particles are calle...
Fong, Sophia Yui Kau; Ibisogly, Asiye; Bauer-Brandl, Annette
2015-12-30
The poor aqueous solubility of BCS Class II drugs represents a major challenge for oral dosage form development. Using celecoxib (CXB) as model drug, the current study adopted a novel solid phospholipid nanoparticle (SPLN) approach and compared the effect of two commonly used industrial manufacturing methods, spray- and freeze-drying, on the solubility and dissolution enhancement of CXB. CXB was formulated with Phospholipoid E80 (PL) and trehalose at different CXB:PL:trehalose ratios, of which 1:10:16 was the optimal formulation. Spherical amorphous SPLNs with average diameters solid PL dispersion with larger particle sizes were prepared by freeze-drying. Formulations from both methods significantly enhanced the dissolution rates, apparent solubility, and molecularly dissolved concentration of CXB in phosphate buffer (PBS, pH 6.5) and in biorelevant fasted state simulated intestinal fluid (FaSSIF, pH 6.5) (p<0.05). While similar dissolution rates were found, the spray-dried SPLNs had a larger enhancement in apparent solubility (29- to 132-fold) as well as molecular solubility (18-fold) of CXB at equilibrium (p<0.05). The strong capability of the spray-dried SPLNs to attain 'true' supersaturation state makes them a promising approach for bioavailability enhancement of poorly soluble drugs. PMID:26468038
The neutron superfluidity in the inner crust of a neutron star has traditionally been studied considering either homogeneous neutron matter or a small number of nucleons confined inside the spherical Wigner-Seitz cell. Drawing analogies with the recently discovered multiband superconductors, we have solved the anisotropic multiband BCS gap equations with Bloch boundary conditions, thus providing a unified description taking consistently into account both the free neutrons and the nuclear clusters. Calculations have been carried out using the effective interaction underlying our recent Hartree-Fock-Bogoliubov nuclear mass model HFB-16. We have found that even though the presence of inhomogeneities lowers the neutron pairing gaps, the reduction is much less than that predicted by previous calculations using the Wigner-Seitz approximation. We have studied the disappearance of superfluidity with increasing temperature. As an application we have calculated the neutron specific heat, which is an important ingredient for modeling the thermal evolution of newly born neutron stars. This work provides a new scheme for realistic calculations of superfluidity in neutron-star crusts.
Theory of superconductivity. II. Excited Cooper pairs. Why does sodium remain normal down to 0 K?
Based on a generalized BCS Hamiltonian in which the interaction strengths (V11, V22, V12) among and between electron (12) and hole (2) Cooper pairs are differentiated, the thermodynamic properties of a type-I superconductor below the critical temperature Tc are investigated. An expression for the ground-state energy, W - W0, relative to the unperturbed Block system is obtained. The usual BCS formulas are obtained in the limits: (all) Vjl = V0, N1(0) = N2(0). Any excitations generated through the BCS interaction Hamiltonian containing Vjl must involve Cooper pairs of antiparallel spins and nearly opposite momenta. The nonzero momentum or excited Cooper pairs below Tc are shown to have an excitation energy band minimum lower than the quasi-electrons, which were regarded as the elementary excitations in the original BCS theory. The energy gap var-epsilon g (T) defined relative to excited and zero-momentum Copper pairs (when Vjl > 0) decreases from var-epsilon g(0) to 0 as the temperature T is raised from 0 to Tc. If electrons only are available as in a monovalent metal like sodium (V12 = 0), the energy constant Δ1 is finite but the energy gap vanishes identically for all T. In agreement with the BCS theory, the present theory predicts that a pure nonmagnetic metal in any dimensions should have a Cooper-pair ground state whose energy is lower than that of the Bloch ground state. Additionally it predicts that a monovalent metal should remain normal down to 0 K, and that there should be no strictly one-dimensional superconductor
Heimbach, Tycho; Xia, Binfeng; Lin, Tsu-Han; He, Handan
2012-01-01
Practical food effect predictions and assessments were described using in silico, in vitro, and/or in vivo preclinical data to anticipate food effects and Biopharmaceutics Classification System (BCS)/Biopharmaceutics Drug Disposition Classification System (BDDCS) class across drug development stages depending on available data: (1) limited in silico and in vitro data in early discovery; (2) preclinical in vivo pharmacokinetic, absorption, and metabolism data at candidate selection; and (3) ph...
The XMM-BCS galaxy cluster survey: I. The X-ray selected cluster catalog from the initial 6 deg$^2$
Šuhada, R; Böhringer, H; Mohr, J J; Chon, G; Finoguenov, A; Fassbender, R; Desai, S; Armstrong, R; Zenteno, A; Barkhouse, W A; Bertin, E; Buckley-Geer, E J; Hansen, S M; High, F W; Lin, H; Mühlegger, M; Ngeow, C C; Pierini, D; Pratt, G W; Verdugo, M; Tucker, D L
2011-01-01
The XMM-Newton - Blanco Cosmology Survey project (XMM-BCS) is a coordinated X-ray, optical and mid-infrared cluster survey in a field also covered by Sunyaev-Zel'dovich effect surveys by the South Pole Telescope and the Atacama Cosmology Telescope. The aim of the project is to study the cluster population in a 14 deg$^2$ field. In this work, we present a catalog of 46 X-ray selected clusters from the initial 6 deg$^2$ survey core. We describe the XMM-BCS source detection pipeline and derive physical properties of the clusters. We provide photometric redshift estimates derived from the BCS imaging data and spectroscopic redshift measurements for a low redshift subset of the clusters. We derive the cluster log N - log S relation using an approximation to the survey selection function and find it in good agreement with previous studies. We carry out an initial comparison between X-ray luminosity derived masses and masses from optical estimators from the Southern Cosmology Survey for a subset of the cluster sampl...
Research in the theory of condensed matter and elementary particles. Progress report
Progress is described on research concerned with problems occupying the common ground between quantum field theory and statistical mechanics. Research was conducted on conformal field theory and two dimensional critical phenomena; on formation of large scale structures in dynamical systems; on fermion-boson mass relations in BCS type theories; on properties of quark-gluon plasmas; on random walks in random environments; on chiral symmetry breaking in lattice gauge theories, on supersymmetric derivations of anomaly formulas and index theorems; and on the problems of exact chiral symmetry in lattice fermion theories. Publications are listed. 46 references
The low lying states and especialy the extraordinary behaviour of the first excited O+ state as a function of neutron number in the sequence of nuclei, 68Ge, 70Ge, 72Ge, 74Ge, 76Ge, are described (except for 76Ge) by introducing a s'-boson into the interacting boson model (IBM) which usually involves only s- and d-bosons. This introduction could be understood by considering results from BCS-RPA calculations in the neutron configuration only. BCS-RPA theory is, however, shown to be a poor approximation in the case under consideration. Results from the exact diagonalisation of the Hamiltonian for the charge independant pairing interaction in both the proton and neutron configuration are discussed. 7 figs., 2 tabs., 21 refs
Sievens-Figueroa, Lucas; Bhakay, Anagha; Jerez-Rozo, Jackeline I; Pandya, Natasha; Romañach, Rodolfo J; Michniak-Kohn, Bozena; Iqbal, Zafar; Bilgili, Ecevit; Davé, Rajesh N
2012-02-28
The design and feasibility of a simple process of incorporating stable nanoparticles into edible polymer films is demonstrated with the goal of enhancing the dissolution rate of poorly water soluble drugs. Nanosuspensions produced from wet stirred media milling (WSMM) were transformed into polymer films containing drug nanoparticles by mixing with a low molecular weight hydroxylpropyl methyl cellulose (HPMC E15LV) solution containing glycerin followed by film casting and drying. Three different BCS Class II drugs, naproxen (NPX), fenofibrate (FNB) and griseofulvin (GF) were studied. The influence of the drug molecule on the film properties was also investigated. It was shown that film processing methodology employed has no effect on the drug crystallinity according to X-ray diffraction (XRD) and Raman spectroscopy. Differences in aggregation behavior of APIs in films were observed through SEM and NIR chemical imaging analysis. NPX exhibited the strongest aggregation compared to the other drugs. The aggregation had a direct effect on drug content uniformity in the film. Mechanical properties of the film were also affected depending on the drug-polymer interaction. Due to strong hydrogen bonding with the polymer, NPX exhibited an increase in Young's Modulus (YM) of approximately 200%, among other mechanical properties, compared to GF films. A synergistic effect between surfactant/polymer and drug/polymer interactions in the FNB film resulted in an increase of more than 600% in YM compared to the GF film. The enhancement in drug dissolution rate of films due to the large surface area and smaller drug particle size was also demonstrated. PMID:22178619
Proposed experimental test of an alternative electrodynamic theory of superconductors
Highlights: • A new experimental test of electric screening in superconductors is proposed. • The electric screening length is predicted to be much larger than in normal metals. • The reason this was not seen in earlier experiments is explained. • This is not predicted by the conventional BCS theory of superconductivity. - Abstract: An alternative form of London’s electrodynamic theory of superconductors predicts that the electrostatic screening length is the same as the magnetic penetration depth. We argue that experiments performed to date do not rule out this alternative formulation and propose an experiment to test it. Experimental evidence in its favor would have fundamental implications for the understanding of superconductivity
Hao Guo
2015-01-01
Full Text Available Recent experimental progress allows for exploring some important physical quantities of ultracold Fermi gases, such as the compressibility, spin susceptibility, viscosity, optical conductivity, and spin diffusivity. Theoretically, these quantities can be evaluated from suitable linear response theories. For BCS superfluid, it has been found that the gauge invariant linear response theories can be fully consistent with some stringent consistency constraints. When the theory is generalized to stronger than BCS regime, one may meet serious difficulties to satisfy the gauge invariance conditions. In this paper, we try to construct density and spin linear response theories which are formally gauge invariant for a Fermi gas undergoing BCS-Bose-Einstein Condensation (BEC crossover, especially below the superfluid transition temperature Tc. We adapt a particular t-matrix approach which is close to the G0G formalism to incorporate noncondensed pairing in the normal state. We explicitly show that the fundamental constraints imposed by the Ward identities and Q-limit Ward identity are indeed satisfied.
Uribe, J.; Oechel, W. C.
2012-12-01
Mangrove forests are among the most productive ecosystems within the tropical and subtropical coastlines of the world. There is currently limited research on mangrove carbon sequestration potentials but with ongoing climate change and rising atmospheric carbon dioxide (CO2) levels, an understanding of carbon exchange in mangroves forests and the environmental controls influencing fluxes is extremely important for understanding their role in the global carbon cycle and their potential as stores of CO2. In this study, CO2 flux was evaluated for a subtropical mangrove ecosystem in the arid region of Magdalena Bay BCS, Mexico. Measurements were taken using an eddy covariance system above the canopy during January 8 to the 30, and currently from June 21 to August 28, in 2012. The mangrove forest is located (N25° 15'75", W112° 04'79") near the town of Puerto Lopez Mateos, Mexico. During this time period environmental variables such as Net Radiation, photosynthetically active radiation (PAR), air temperature, humidity, ground heat flux, soil temperature and tidal height were measured together with the CO2 flux in order to determine the environmental influence on the fluxes. Preliminary results showed a clear diurnal pattern in CO2 flux that showed high sinks when light availability was high. During January, the winter dry season environmental conditions remained relatively cool with an average air temperature of 17 oC and consistently cloudless days. During this period CO2 flux was -1.3 μmol C m-2s-1, which means that for the month of January, there was a net uptake of carbon by the mangrove ecosystem. For the summer period the development of the data collection for a longer term as well as further correlation analysis with environmental data is currently underway, however expectations are that seasonal variations of CO2 flux can be seen due to longer and more intense periods of solar irradiance as well as the effect of high temperature (+30° C) days. Indirect effects
XIEBing_Hao; ZHANGHong－Biao; 等
2002-01-01
An algebraic diagonalization method is proposed.As two examples,the Hamiltonians of BCS ground state under mean-field approximation and XXZ antiferromagnetic model in linear spin-wave frame have been diagonalized by using SU(2),SU(1,1) Lie algebraic method,respectively.Meanwhile,the eignenstates of the above two models are revealed to be SU(2),SU(1,1) coherent states,respectively,The relation between the usual Bogoliubov-Valatin transformation and the algebraic method in a special case is also discussed.
Some Applications of Eliashberg Theory
Akis, Richard J.
Eliashberg theory, which was formulated assuming that the electron-phonon interaction is the mechanism for superconductivity, has been very successful in explaining the physical properties of most superconductors. Eliashberg theory is an extension of BCS theory, the original microscopic theory of superconductivity. BCS theory is recovered from Eliashberg theory in the weak electron-boson coupling limit. Recently, a new challenge to Eliashberg theory has been brought forth by the discovery of a new class of superconductors known as the high T_{c} oxides. As of this writing, the question of what is the superconducting mechanism for these materials is still unanswered. In this thesis, many superconducting properties have been calculated mainly in an effort to see if Eliashberg theory may still be applicable to these materials. The approach of this effort has depended on the property being studied. In this case of the critical temperature and the isotope effect, a great deal of work has been put in to fit actual experimental results, particularly for the isotope effect. We shall show that two distinct models, one with an additional electronic mechanism along with the phonons and the other with a very large coulomb repulsion, may be able to explain the experimental results. For the electronic specific heat, maxima that should not be exceeded by an Eliashberg superconductor are established for several quantities associated with this physical property. Unfortunately, some experimental values for these quantities appear to exceed these maxima. In the case of the the nuclear spin relaxation, which has not been very extensively studied in the past, we shall look at how the coherence peak in the relaxation rate can be reduced as a function of coupling strength and draw conclusions that are applicable to conventional superconductors. The behaviour of this property in the oxides is not ignored however, and some fitting of experiment including anisotrophy as well as
Jimenez Grajales, H. R.; Agredano Diaz, Jaime; Gonzalez Galarza, R.; Munguia del Rio, G. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)
2010-11-15
forma de produccion de electricidad es al dia de hoy una opcion bastante madura, en razon de los beneficios que esta modalidad de produccion de electricidad aporta tanto al usuario como a la red electrica. En Mexico cada vez son mas los usuarios del servicio electrico que se ven motivados a invertir en este tipo de sistemas. En este articulo se analiza el caso particular de un usuario de tarifa DAC (Demanda de Alto Consumo) en la ciudad de La Paz, Baja California Sur (BCS), quien cuenta con un SFVI monofasico de 6 kWp instalado en el techo de su casa. Los resultados que se reportan provienen de datos obtenidos por el IIE durante un periodo de monitoreo de tres anos de la operacion del sistema. Los resultados incluyen informacion climatologica, balances de energia y potencia, potencias maximas, produccion y perdidas normalizadas, eficiencia del generador fotovoltaico y de los inversores; entre otros indices de desempeno. El documento resalta el impacto que tiene el SFVI sobre el consumo electrico en el inmueble y en el monto de la factura que el usuario finalmente paga a la compania suministradora del servicio electrico.
SLAP和BCS方法处理对关联的比较%Comparison for the treatment of paring correlations in SLAP and BCS methods
曹向阳; 黄海; 郭建友
2015-01-01
The shell‐model‐like approach (SLAP) and BCS methods were used to treat the pairing correlations for an ideal model .The total energy ,pairing energy ,particle energy and particle occupation together with their evolutions with the pairing strength were obtained . The research indicated that the phase transition from the super fluid to the normal reflected by BCS was clearer ,but SLAP might be more reasonable method for describing physics parameters w hich had obvious relations with the particle number .%基于能级均匀分布的理想模型，分别用SLAP和BCS方法处理对关联，计算体系的总能量、对能、单粒子能量及其占据几率，展示总能量、对能和单粒子能量随对力强度因子变化的情况，比较SLAP和BCS方法计算结果的差异。研究表明：BCS方法能够明显地反映从超流态到正常态的相变，SLAP方法更适合描述与粒子数关系明显的物理量。
Nader, Ahmed M; Quinney, Sara K; Fadda, Hala M; Foster, David R
2016-07-01
Nifedipine is a BCS Class II drug used for treatment of hypertension and preterm labor. Large inter-patient variability in nifedipine absorption results in variable exposure among different patients. We conducted in vitro dissolution studies to compare nifedipine dissolution from immediate release (IR) capsules with different volumes of dissolution media. Results from dissolution studies were used to design a crossover study in healthy volunteers to evaluate the effect of coadministered water volume with nifedipine 10 mg IR capsules on nifedipine pharmacokinetics, especially absorption (C max, t max, and AUC0-6). Dissolution studies demonstrated that larger gastric fluid volumes result in enhanced nifedipine dissolution from 10 mg IR cosolvent capsules (73 vs. 17% in 200 and 100 mL simulated gastric fluid, respectively, at 30 min). The pharmacokinetic crossover study in healthy volunteers (N = 6) did not show a significant effect of the water volume administered with the capsule (50 vs. 250 mL) on C max, t max, or AUC0-6 of orally administered nifedipine IR capsules (10 mg). However, administration of large water volumes resulted in lower variability in nifedipine C max (47 vs. 70% for 250 and 50 mL, respectively). Administration of large water volumes with nifedipine 10 mg IR cosolvent capsules may reduce inter-individual variability in plasma exposure. Evaluation of similar effects in other BCS Class II drugs is recommended. PMID:27106837
Venturi, T; Dallacasa, D; Cassano, R; Brunetti, G; Bardelli, S; Setti, G
2008-01-01
We present the results of the GMRT cluster radio halo survey. The main purposes of our observational project are to measure which fraction of massive galaxy clusters in the redshift range z=0.2--0.4 hosts a radio halo, and to constrain the expectations of the particle re--acceleration model for the origin of the non--thermal radio emission. We selected a complete sample of 50 clusters in the X-ray band from the REFLEX (27) and the eBCS (23) catalogues. In this paper we present Giant Metrewave Radio Telescope (GMRT) observations at 610 MHz for all clusters still lacking high sensitivity radio information, i.e. 16 eBCS and 7 REFLEX clusters, thus completing the radio information for the whole sample. The typical sensitivity in our images is in the range 1$\\sigma \\sim 35-100 \\mu$Jy b$^{-1}$. We found a radio halo in A697, a diffuse peripheral source of unclear nature in A781, a core--halo source in Z7160, a candidate radio halo in A1682 and ``suspect'' central emission in Z2661. Including the literature informat...
Magdalena Lagunas-Vázquez
2008-01-01
Full Text Available En este artículo se describe la experiencia de investigación participativa donde se destaca la importancia de la vinculación entre los actores sociales (en este caso de áreas rurales protegidas, el sector académico y las organizaciones no gubernamentales. Se analizan los resultados de una evaluación rural participativa (ERP llevada a cabo en la Reserva de la Biosfera El Vizcaíno, BCS, México. Además de identificar lo que los actores sociales perciben como problemas y las formas en que proponen vías de solución, se logró obtener información acerca del uso de los recursos naturales por parte de los residentes de las comunidades y se formuló un plan comunitario de uso de los mismos.
Heike Kotarsky
Full Text Available BACKGROUND & AIMS: Liver is a target organ in many mitochondrial disorders, especially if the complex III assembly factor BCS1L is mutated. To reveal disease mechanism due to such mutations, we have produced a transgenic mouse model with c.232A>G mutation in Bcs1l, the causative mutation for GRACILE syndrome. The homozygous mice develop mitochondrial hepatopathy with steatosis and fibrosis after weaning. Our aim was to assess cellular mechanisms for disease onset and progression using metabolomics. METHODS: With mass spectrometry we analyzed metabolite patterns in liver samples obtained from homozygotes and littermate controls of three ages. As oxidative stress might be a mechanism for mitochondrial hepatopathy, we also assessed H(2O(2 production and expression of antioxidants. RESULTS: Homozygotes had a similar metabolic profile at 14 days of age as controls, with the exception of slightly decreased AMP. At 24 days, when hepatocytes display first histopathological signs, increases in succinate, fumarate and AMP were found associated with impaired glucose turnover and beta-oxidation. At end stage disease after 30 days, these changes were pronounced with decreased carbohydrates, high levels of acylcarnitines and amino acids, and elevated biogenic amines, especially putrescine. Signs of oxidative stress were present in end-stage disease. CONCLUSIONS: The findings suggest an early Krebs cycle defect with increases of its intermediates, which might play a role in disease onset. During disease progression, carbohydrate and fatty acid metabolism deteriorate leading to a starvation-like condition. The mouse model is valuable for further investigations on mechanisms in mitochondrial hepatopathy and for interventions.
Recent development of the neutron matter research, especially on the low-density region where S wave components are dominant, is reported based on the first principle calculations of the lattice effective field theory. Second order perturbation is taken into account in the Hamiltonian form on the lattice which does not include π mesons. Determinant Quantum Monte Carlo calculation based on the grand canonical ensemble is used. Physical quantities are calculated considering their corresponding correlation functions. Results on the S-wave super fluidity pairing gap near absolute zero, on the super- and normal-fluidity phase transition temperature and on the pairing temperature scale related to the pseudogaps are described. They are finally extrapolated to the thermodynamic limit or continuity. Results of the pairing gap are in agreement with the recent Green function Monte Carlo calculations as well as the path integral ones within the statistical errors. The results are lower, on the other hand, compared to the results of weak coupling BCS theory using realistic forces. It further becomes clear that it is not so significantly suppressed as suggested by the numbers of beyond BCS theory in the recent years. Phase diagram at finite temperature is discussed. It is shown that the pseudo gap exists for neutron matter even at very low density region and it is in the BCS-BEC crossover state. (S. Funahashi)
A unified theory of superconductivity
Huang, Xiuqing
2008-01-01
In this work, we argue that the phonon-mediated BCS theory may be incorrect. Two kinds of glues, pairing (pseudogap) glue and superconducting glue, are suggested based on a real space Coulomb confinement effect. The scenarios provide a unified explanation of the pairing symmetry, pseudogap and superconducting states, spin--charge stripe order, magic doping fractions and vortex structures in conventional and unconventional (the high-Tc cuprates, MgB2 and the newly-discovered Fe-based family) superconductors. The theory agrees with the existence of a pseudogap in high-temperature superconductors, while no pseudogap feature could be observed in MgB2, iron-based and most of the conventional superconductors. Our results indicate that the superconducting phase can coexist with a triangular vortex lattice in pure MgB2 single crystal with a charge carrier density n=1.49*10^22/cm3. For iron-based superconductors, the relationship between the superconducting vortex phases and the optimal doping levels are analytically ...
Standard 3D-CRT after BCS may cause skin toxicity with a wide range of intensity including acute effects like erythema or late effects. In order to reduce these side effects it is mandatory to identify potential factors of influence in breast cancer patients undergoing standard three-dimensional conformal radiation therapy (3D-CRT) of the breast and modern systemic therapy. Between 2006 and 2010 a total of 211 breast cancer patients (median age 52,4 years, range 24–77) after BCS consecutively treated in our institution with 3D-CRT (50 Gy whole breast photon radiotherapy followed by 16 Gy electron boost to the tumorbed) were evaluated with special focus on documented skin toxicity at the end of the 50 Gy-course. Standardized photodocumentation of the treated breast was done in each patient lying on the linac table with arms elevated. Skin toxicity was documented according to the common toxicity criteria (CTC)-score. Potential influencing factors were classified in three groups: patient-specific (smoking, age, breast size, body mass index = BMI, allergies), tumor-specific (tumorsize) and treatment-specific factors (antihormonal therapy with tamoxifen or aromatase inhibitors, chemotherapy). Uni- and multivariate statistical analyses were done using IBM SPSS version 19. After 50 Gy 3D-CRT to the whole breast 28.9% of all 211 patients had no erythema, 62.2% showed erythema grade 1 (G1) and 8.5% erythema grade 2. None of the patients had grade 3/4 (G3/4) erythema. In univariate analyses a significant influence or trend on the development of acute skin toxicities (erythema G0 versus G1 versus G2) was observed for larger breast volumes (p=0,004), smoking during radiation therapy (p=0,064) and absence of allergies (p=0,014) as well as larger tumorsize (p=0,009) and antihormonal therapy (p=0.005). Neither patient age, BMI nor choice of chemotherapy showed any significant effect on higher grade toxicity. In the multivariate analysis, factors associated with higher grade
Lehto, Paula; Kortejärvi, Hanna; Liimatainen, Anni; Ojala, Krista; Kangas, Heli; Hirvonen, Jouni; Tanninen, Veli Pekka; Peltonen, Leena
2011-08-01
The usefulness of selected conventional surfactant media to enhance dissolution of BCS class II drugs similarly to fasted state simulated intestinal fluid (FaSSIF) and to predict the absorption of drugs in vivo was evaluated. Dissolution behavior of danazol (Danol), spironolactone (Spiridon) and N74 (phase I compound) was compared between FaSSIF, containing physiological levels of sodium taurocholate (STC) and lecithin, and dissolution media containing various concentrations of anionic surfactant, sodium lauryl sulfate (SLS) or non-ionic surfactant, polysorbate (Tween) 80. Although these media differed largely in their solubilization ability, micelle size, diffusivity and surface tension, similar dissolution enhancing levels were achieved between FaSSIF and drug-specific concentrations of conventional surfactants. The dissolution enhancement was shown, however, to be important only for danazol and N74, molecules that are characterized by high hydrophobicity. An in vivo pharmacokinetic dog study was carried out with N74. Comparison of observed plasma profiles with simulated profiles obtained using compartmental absorption and transit model (CAT) indicated that 0.1% SLS medium was the best to predict in vivo plasma profiles and pharmacokinetic parameters (C(max) and AUC). This study demonstrates the potential of substituting FaSSIF with more simple and cost-effective conventional surfactant media. Use of in vivo prognostic amounts of synthetic surfactants in dissolution testing could largely assist in industrial drug development as well as in quality control purposes. PMID:21329757
Heinen, Christian A; Reuss, Stefan; Amidon, Gordon L; Langguth, Peter
2013-11-01
In the current study the involvement of ion pair formation between bile salts and trospium chloride (TC), a positively charged Biopharmaceutical Classification System (BCS) class III substance, showing a decrease in bioavailability upon coadministration with food (negative food effect) was investigated. Isothermal titration calorimetry provided evidence of a reaction between TC and bile acids. An effect of ion pair formation on the apparent partition coefficient (APC) was examined using (3)H-trospium. The addition of bovine bile and bile extract porcine led to a significant increase of the APC. In vitro permeability studies of trospium were performed across Caco-2-monolayers and excised segments of rat jejunum in a modified Ussing chamber. The addition of bile acids led to an increase of trospium permeation across Caco-2-monolayers and rat excised segments by approximately a factor of 1.5. The addition of glycochenodeoxycholate (GCDC) was less effective than taurodeoxycholate (TDOC). In the presence of an olive oil emulsion, a complete extinction of the permeation increasing effects of bile salts was observed. Thus, although there are more bile acids in the intestine in the fed state compared to the fasted state, these are not able to form ion pairs with trospium in fed state, because they are involved in the emulsification of dietary fats. In conclusion, the formation of ion pairs between trospium and bile acids can partially explain its negative food effect. Our results are presumably transferable to other organic cations showing a negative food effect. PMID:23750707
The chemical potential μ of a many-body system is valuable since it carries fingerprints of phase changes. Here, we summarize results for μ for a three-dimensional electron liquid in terms of average kinetic and potential energies per particle. The difference between μ and the energy per particle is found to be exactly the electrostatic potential step at the surface. We also present calculations for an integrable one-dimensional many-body system with delta function interactions, exhibiting a BCS-BEC crossover. It is shown that in the BCS regime the chemical potential can be expressed solely in terms of the ground-state energy per particle. A brief discussion is also included of the strong coupling BEC limit
A unified microscopic theory of superfluidity and superconductivity
A consistent and unified microscopic theory of a novel two-stage Fermi-Bose liquid (FBL) scenarios of superfluidity and superconductivity is developed as a combined theory of Fermi- and superfluid (SF) Bose-liquid. Modified and generalized BCS like pairing theory of fermions is presented. In analogy to that a detail boson pairing theory is developed. The single particle (SPC) and pair condensation (PC) features of an attracting 3d- and 2d-Bose gas as a function of the interboson coupling constant in the complete range 0 ≤ T ≤ Tc is studied in detail. It is shown that such SPC and PC of an attracting composite bosons (Cooper pairs, bipolarons, holons, 4He atoms, deuterons, alpha particles) lies on the basis of superfluidity both in Fermi and Bose systems. It is argued that the coexistence of the order parameters of attracting fermions ΔF and bosons ΔB leads to the superfluidity and superconductivity by two FBL scenarios. One of these scenarios is realized in so-called fermion superconductors (FSC) and other -in boson one (BSC) in which the gapless superconductivity is caused by absence of the gap ΔSF in the excitation spectrum of bosons and not by presence of point or line nodes of the BCS-like gap ΔF. The new adequate determination for basic superconducting parameters of FSC and BSC are given. The necessary and sufficient microscopic criterions for a superfluidity is formulated. The theory proposed is consistent with the different experimental data available in 4He, 3He, superconductors, nucleis, neutron stars and others. (author). 133 refs, 14 figs
于现军
2005-01-01
详细描述了通用燃烧优化控制技术(BCS)以及用BCS来改造链条炉并获得显著效果的应用情况,解决了中小企业普遍使用的链条炉存在的燃烧效率低、污染环境等问题.
Reyna Ibáñez Pérez
2011-01-01
Full Text Available Uno de los mayores anhelos de toda sociedad es alcanzar un nivel económico elevado; otro es el de tener la oportunidad de disfrutar eternamente de los servicios proporcionados por la madre naturaleza. Sin embargo, las tendencias indican que se experimenta un deterioro importante en el ambiente, a la par, de una elevada concentración de pobreza. Esto, aunado a la dependencia que algunas entidades y países han desarrollado en relación a actividades -como la turística- se ha convertido en una de las preocupaciones centrales de los gobiernos, el establecer mediciones para determinar si las pautas de crecimiento y desarrollo, van acorde con el cuidado del ambiente y el bienestar de las personas. Por ello, dentro de este artículo se analizan la evolución del crecimiento económico y posicionamiento de Baja California Sur (BCS -un estado con importante actividad turística- en el Barómetro de Sustentabilidad. En la introducción, se aprecia la evolución del concepto de crecimiento y desarrollo, para continuar con la caracterización de la zona de estudio. Posteriormente, se detalla la metodología empleada. Enseguida, se estudia la situación actual del sector turístico en BCS y la evolución del crecimiento y desarrollo económico. En el análisis de resultados, se describen los factores que ubican a BCS en un nivel Medio de sustentabilidad. Finalmente, se presentan algunas reflexiones en relación a los retos que en materia de turismo, crecimiento económico, desarrollo sustentable afronta BCS.
Mathematical methods of many-body quantum field theory
Lehmann, Detlef
2004-01-01
Mathematical Methods of Many-Body Quantum Field Theory offers a comprehensive, mathematically rigorous treatment of many-body physics. It develops the mathematical tools for describing quantum many-body systems and applies them to the many-electron system. These tools include the formalism of second quantization, field theoretical perturbation theory, functional integral methods, bosonic and fermionic, and estimation and summation techniques for Feynman diagrams. Among the physical effects discussed in this context are BCS superconductivity, s-wave and higher l-wave, and the fractional quantum Hall effect. While the presentation is mathematically rigorous, the author does not focus solely on precise definitions and proofs, but also shows how to actually perform the computations.Presenting many recent advances and clarifying difficult concepts, this book provides the background, results, and detail needed to further explore the issue of when the standard approximation schemes in this field actually work and wh...
Choy, Ting-Pong
One of the leading problems in condensed matter physics is what state of matter obtain when there is a strong Coulomb repulsion between the electrons. One of the exotic examples is the high temperature superconductivity which was discovered in copper-oxide ceramics (cuprates) over twenty years ago. Thus far, a satisfactory theory is absent. In particular, the nature of the electron state outside the superconducting phase remains controversial. In analogy with the BCS theory of a conventional superconductor, in which the metal is well known to be a Fermi liquid, a complete understanding of the normal state of cuprate is necessary prior to the study of the superconducting mechanism in the high temperature superconductors. In this thesis, we will provide a theory for these exotic normal state properties by studying the minimal microscopic model which captures the physics of strong electron correlation. Even in such a simple microscopic model, striking properties including charge localization and presence of a Luttinger surface resemble the normal state properties of cuprate. An exact low energy theory of a doped Mott insulator will be constructed by explicitly integrating (rather than projecting) out the degrees of freedom far away from the chemical potential. The exact low energy theory contains degrees of freedom that cannot be obtained from projective schemes. In particular, a charge 2e bosonic field which is not made out of elemental excitations emerges at low energies. Such a field accounts for dynamical spectral weight transfer across the Mott gap. At half-filling, we show that two such excitations emerge which play a crucial role in preserving the Luttinger surface along which the single-particle Green function vanishes. We also apply this method to the Anderson-U impurity and show that in addition to the Kondo interaction, bosonic degrees of freedom appear as well. We show that many of the normal state properties of the cuprates can result from this new charge
Incecayir, Tuba; Tsume, Yasuhiro; Amidon, Gordon L
2013-03-01
The purpose of this study was to investigate labetalol as a potential high permeability reference standard for the application of Biopharmaceutics Classification Systems (BCS). Permeabilities of labetalol and metoprolol were investigated in animal intestinal perfusion models and Caco-2 cell monolayers. After isolating specific intestinal segments, in situ single-pass intestinal perfusions (SPIP) were performed in rats and mice. The effective permeabilities (Peff) of labetalol and metoprolol, an FDA standard for the low/high Peff class boundary, were investigated in two different segments of rat intestine (proximal jejunum and distal ileum) and in the proximal jejunum of mouse. No significant difference was found between Peff of metoprolol and labetalol in the jejunum and ileum of rat (0.33 ± 0.11 × 10(-4) vs 0.38 ± 0.06 × 10(-4) and 0.57 ± 0.17 × 10(-4) vs 0.64 ± 0.30 × 10(-4) cm/s, respectively) and in the jejunum of mouse (0.55 ± 0.05 × 10(-4) vs 0.59 ± 0.13 × 10(-4) cm/s). However, Peff of metoprolol and labetalol were 1.7 and 1.6 times higher in the jejunum of mouse, compared to the jejunum of rat, respectively. Metoprolol and labetalol showed segmental-dependent permeability through the rat intestine, with increased Peff in the distal ileum in comparison to the proximal jejunum. Most significantly, Peff of labetalol was found to be concentration-dependent. Decreasing concentrations of labetalol in the perfusate resulted in decreased Peff compared to Peff of metoprolol. The intestinal epithelial permeability of labetalol was lower than that of metoprolol in Caco-2 cells at both apical pH 6.5 and 7.5 (5.96 ± 1.96 × 10(-6) vs 9.44 ± 3.44 × 10(-6) and 15.9 ± 2.2 × 10(-6) vs 23.2 ± 7.1 × 10(-6) cm/s, respectively). Labetalol exhibited higher permeability in basolateral to apical (BL-AP) compared to AP-BL direction in Caco-2 cells at 0.1 times the highest dose strength (HDS) (46.7 ± 6.5 × 10(-6) vs 14.2 ± 1.5 × 10(-6) cm/s). The P
Incecayir, Tuba; Tsume, Yasuhiro; Amidon, Gordon L.
2013-01-01
The purpose of this study was to investigate labetalol as a potential high permeability reference standard for the application of Biopharmaceutics Classification Systems (BCS). Permeabilities of labetalol and metoprolol were investigated in animal intestinal perfusion models and Caco-2 cell monolayers. After isolating specific intestinal segments, in situ single-pass intestinal perfusions (SPIP) were performed in rats and mice. The effective permeabilities (Peff) of labetalol and metoprolol, an FDA standard for the low/high Peff class boundary, were investigated in two different segments of rat intestine (proximal jejunum and distal ileum), and in the proximal jejunum of mouse. No significant difference was found between Peff of metoprolol and labetalol in the jejunum and ileum of rat (0.33±0.11 ×10−4 vs. 0.38±0.06 ×10−4 and 0.57±0.17 ×10−4 vs. 0.64±0.30 ×10−4 cm/s, respectively) and in the jejunum of mouse (0.55±0.05 ×10−4 vs. 0.59±0.13 ×10−4 cm/s). However, Peff of metoprolol and labetalol were 1.7 and 1.6 times higher in the jejunum of mouse, compared to the jejunum of rat, respectively. Metoprolol and labetalol showed segmental dependent permeability through the rat intestine, with increased Peff in the distal ileum in comparison to the proximal jejunum. Most significantly, Peff of labetalol was found to be concentration dependent. Decreasing concentrations of labetalol in the perfusate resulted in decreased Peff compared to Peff of metoprolol. The intestinal epithelial permeability of labetalol was lower than that of metoprolol in Caco-2 cells at both apical pH 6.5 and 7.5 (5.96±1.96 ×10−6 vs. 9.44±3.44 ×10−6 and 15.9±2.2 ×10−6 vs. 23.2±7.1 ×10−6 cm/s, respectively). Labetalol exhibited higher permeability in basolateral to apical (BL-AP) compared to AP-BL direction in Caco-2 cells at 0.1 times the highest dose strength (HDS) (46.7±6.5 ×10−6 vs. 14.2±1.5 ×10−6 cm/s). The P-gp inhibitor, verapamil significantly
Karmakar, Madhuparna; Majumdar, Pinaki
2016-05-01
We study s -wave superconductivity in the two-dimensional attractive Hubbard model in an applied magnetic field, assume the extreme Pauli limit, and examine the role of spatial fluctuations in the coupling regime corresponding to BCS-BEC crossover. We use a decomposition of the interaction in terms of an auxiliary pairing field, retain the static mode, and sample the pairing field via a Monte Carlo approach. The method requires iterative solution of the Bogoliubov-de-Gennes equations for amplitude- and phase-fluctuating configurations of the pairing field. We establish the full thermal phase diagram of this strong-coupling problem. At low field we observe the magnetized but homogeneous "breached pair" superfluid phase. It reveals that Tc scales an order of magnitude below the mean-field estimate, spontaneous inhomogeneity in the field-induced magnetization, and a strong nonmonotonicity in the temperature dependence of the low-energy density of states. We compare our results to the experimental phase diagram of the imbalanced Fermi gas at unitarity. At higher field we obtain the modulated Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phases. The thermal transition from the FFLO phases to the normal state is strongly first order. We track the fermionic momentum distribution, the density of states, and the pairing structure factor deep into the normal state. The pairing structure factor retains weak signature of finite momentum pairing to a high temperature despite the low Tc itself, while the spin-resolved density of states changes from the "pseudogapped" FFLO character to gapless and pseudogapped again with increasing temperature.
Shape Transition in Rare-Earth Nuclei in Relativistic Mean Field Theory
B K Agrawal; Sil, Tapas; Samaddar, S. K.; De, J. N.
2000-01-01
A systematic study of the temperature dependence of the shapes and pairing gaps of some isotopes in the rare-earth region is made in the relativistic Hartree-BCS theory. Thermal response to these nuclei is always found to lead to a phase transition from the superfluid to the normal phase at a temperature $T_{\\Delta}\\sim 0.4 - 0.8$ MeV and a shape transition from prolate to spherical shapes at $T_c\\sim 1.0 - 2.5$ MeV. These shape transition temperatures are appreciably higher than the correspo...
Pairing and seniority in an equations-of-motion approach to nuclear structure theory
Covello, A.; Andreozzi, F.; Gargano, A.; Porrino, A. (Naples Univ. (Italy). Dipt. di Scienze Fisiche Istituto Nazionale di Fisica Nucleare, Naples (Italy))
1990-01-01
In this paper, some achievements of an equations-of-motion approach to nuclear structure theory are discussed. As an introduction to the main subject, a brief survey of some early work is given. We then describe a formalism for treating the pairing-force problem and show, by numerical appllications, that at the lowest order of approximation it provides an advantageous alternative to the BCS method. Finally, we discuss how to treat a general shell-model Hamiltonian within the framework of the seniority scheme. This makes it possible to further reduce seniority-truncated shell-model spaces, as is illustrated by examples. (orig.).
Wæver, Ole
2009-01-01
Kenneth N. Waltz's 1979 book, Theory of International Politics, is the most influential in the history of the discipline. It worked its effects to a large extent through raising the bar for what counted as theoretical work, in effect reshaping not only realism but rivals like liberalism and......-empiricism and anti-positivism of his position. Followers and critics alike have treated Waltzian neorealism as if it was at bottom a formal proposition about cause-effect relations. The extreme case of Waltz being so victorious in the discipline, and yet being consistently mis-interpreted on the question of...
Jara, Pascual; Torrecillas, Blas
1988-01-01
The papers in this proceedings volume are selected research papers in different areas of ring theory, including graded rings, differential operator rings, K-theory of noetherian rings, torsion theory, regular rings, cohomology of algebras, local cohomology of noncommutative rings. The book will be important for mathematicians active in research in ring theory.
Marino Beiras, Marcos
2001-01-01
We give an overview of the relations between matrix models and string theory, focusing on topological string theory and the Dijkgraaf--Vafa correspondence. We discuss applications of this correspondence and its generalizations to supersymmetric gauge theory, enumerative geometry and mirror symmetry. We also present a brief overview of matrix quantum mechanical models in superstring theory.
Rodriguez-Guzman, R; Bertsch, George F
2007-01-01
We describe a procedure for mapping a self-consistent mean-field theory (also known as density functional theory) into a shell model Hamiltonian that includes quadrupole-quadrupole and monopole pairing interactions in a truncated space. We test our method in the deformed N=Z sd-shell nuclei Ne-20, Mg-24 and Ar-36, starting from the Hartree-Fock plus BCS approximation of the USD shell model interaction. A similar procedure is then followed using the SLy4 Skyrme energy density functional in the particle-hole channel plus a zero-range density-dependent force in the pairing channel. Using the ground-state solution of this density functional theory at the Hartree-Fock plus BCS level, an effective shell model Hamiltonian is constructed. We use this mapped Hamiltonian to extract quadrupolar and pairing correlation energies beyond the mean field approximation. The rescaling of the mass quadrupole operator in the truncated shell model space is found to be almost independent of the coupling strength used in the pairing...
Golledge, Reginald G.
2001-01-01
The emergence of geographical theory was an inevitable product of the desire to systematize existing geographic knowledge and to use that systematized base to explore new areas of knowledge. Although the usefulness of theory and predictive models in geography is by now a matter of record, it was not always the case. The usefulness and need for theories was often disputed, despite the oft-repeated argument that theories of location explained the laws of spatial distributions, theories of inter...
The paper traces the development of the String Theory, and was presented at Professor Sir Rudolf Peierls' 80sup(th) Birthday Symposium. The String theory is discussed with respect to the interaction of strings, the inclusion of both gauge theory and gravitation, inconsistencies in the theory, and the role of space-time. The physical principles underlying string theory are also outlined. (U.K.)
Purpose: TP53BP1 is a key component of radiation-induced deoxyribonucleic acid damage repair. The purpose of this study was to evaluate the significance of a known common single nucleotide polymorphism in this gene (rs560191) in patients treated with breast-conserving surgery and whole-breast irradiation (BCS + RT). Methods and Materials: The population consisted of 176 premenopausal women treated with BCS + RT (median follow-up, 12 years). Genomic deoxyribonucleic acid was processed by use of TaqMan assays. Each allele for rs560191 was either C or G, so each patient was therefore classified as CC, CG, or GG. Patients were grouped as GG if they were homozygous for the variant G allele or CC-CG if they carried at least one copy of the common C allele (CC or CG). Results: Of the 176 women, 124 (71%) were CC-CG and 52 (29%) were GG. The mean age was 44 years for GG vs. 38 years for CC-CG (p < 0.001). GG was more common in African-American women than white women (69% vs. 13%, p < 0.001) and more commonly estrogen receptor negative (70% vs. 49%, p = 0.02). There were no significant correlations of rs560191 with other critical variables. Despite the fact that GG patients were older, the 10-year rate of local relapses was higher (22% for GG vs. 12% for CC-CG, p = 0.04). Conclusions: This novel avenue of investigation of polymorphisms in radiation repair/response genes in patients treated with BCS + RT suggests a correlation to local relapse. Additional evaluation is needed to assess the biological and functional significance of these single nucleotide polymorphisms, and larger confirmatory validation studies will be required to determine the clinical implications.
何秋彤; 余以刚; 肖性龙; 吴聪俊; 李志波; 吴晖
2011-01-01
The reaction conditions and analytical parameters of the copper（II）reduction assay with bathocuproinedisulfonic acid disodium salt（BCS）as chelating agent（the CUPRAC-BCS assay）were optimized by the microplate reader.The best factors for analysis at 490nm were as followed：1mmol/L CuSO4,2mmol/L BCS,pH7.4 and reaction time 20min.The antioxidant capacities of 16 herbal tea samples were detected by this novel method.The results showed that CUPRAC-BCS assay was significantly correlated with total phenolic content,DPPH and Fe3＋reducing power assay（P0.05 for all）.The linear range of this method was between 0.1 ~ 0.5mmol/L Trolox equivalents,R2=0.9965.The results showed that CUPRAC-BCS was a fast,simple,suitable and high throughput method for antioxidant capacity assessment.%利用酶标仪对铜离子还原能力法Cu-BCS体系（CUPRAC-BCS法）的测定参数进行了优化,确定的检测条件为：CuSO4溶液浓度为1mmol/L、BCS溶液为2mmol/L、体系pH7.4、反应时间20min,490nm检测。应用新建立的＂CUPRAC-BCS酶标仪法＂对16组凉茶样品抗氧化性进行检测,结果表明该法的测定结果与总酚含量（TPC）、DPPH、Fe3＋还原能力法的相关性均达到显著水平（P〈0.05）。此方法线性范围为0.1～0.5mmol/LTrolox当量,R2=0.9965,是一种快速、简
Of all supergravity theories, the maximal, i.e., N = 8 in 4-dimension or N = 1 in 11-dimension, theory should perform the unification since it owns the highest degree of symmetry. As to the N = 1 in d = 11 theory, it has been investigated how to compactify to the d = 4 theories. From the phenomenological point of view, local SUSY GUTs, i.e., N = 1 SUSY GUTs with soft breaking terms, have been studied from various angles. The structures of extended supergravity theories are less understood than those of N = 1 supergravity theories, and matter couplings in N = 2 extended supergravity theories are under investigation. The harmonic superspace was recently proposed which may be useful to investigate the quantum effects of extended supersymmetry and supergravity theories. As to the so-called Kaluza-Klein supergravity, there is another possibility. (Mori, K.)
Handbook of high-temperature superconductivity theory and experiment
Brooks, James S
2007-01-01
Since the 1980s, a general theme in the study of high-temperature superconductors has been to test the BCS theory and its predictions against new data. At the same time, this process has engendered new physics, new materials, and new theoretical frameworks. Remarkable advances have occurred in sample quality and in single crystals, in hole and electron doping in the development of sister compounds with lower transition temperatures, and in instruments to probe structure and dynamics. Handbook of High-Temperature Superconductvity is a comprehensive and in-depth treatment of both experimental and theoretical methodologies by the the world's top leaders in the field. The Editor, Nobel Laureate J. Robert Schrieffer, and Associate Editor James S. Brooks, have produced a unified, coherent work providing a global view of high-temperature superconductivity covering the materials, the relationships with heavy-fermion and organic systems, and the many formidable challenges that remain.
Linder, Stefan; Foss, Nicolai Juul
2015-01-01
Agency theory studies the problems and solutions linked to delegation of tasks from principals to agents in the context of conflicting interests between the parties. Beginning from clear assumptions about rationality, contracting, and informational conditions, the theory addresses problems of ex...... agency theory to enjoy considerable scientific impact on social science; however, it has also attracted considerable criticism....
Linder, Stefan; Foss, Nicolai Juul
Agency theory studies the problems and solutions linked to delegation of tasks from principals to agents in the context of conflicting interests between the parties. Beginning from clear assumptions about rationality, contracting and informational conditions, the theory addresses problems of ex...... agency theory to enjoy considerable scientific impact on social science; however, it has also attracted considerable criticism....
This article is devoted to a nontechnical review on the present status of string theory towards an ultimate unification of all fundamental interactions including gravity. In particular, we emphasize the importance of string theory as a new theoretical framework in which the long-standing conflict between quantum theory and general relativity is resolved. (author)
Williams, Jeffrey
1994-01-01
Considers the recent flood of anthologies of literary criticism and theory as exemplifications of the confluence of pedagogical concerns, economics of publishing, and other historical factors. Looks specifically at how these anthologies present theory. Cites problems with their formatting theory and proposes alternative ways of organizing theory…
Rowen, Louis H
1991-01-01
This is an abridged edition of the author's previous two-volume work, Ring Theory, which concentrates on essential material for a general ring theory course while ommitting much of the material intended for ring theory specialists. It has been praised by reviewers:**""As a textbook for graduate students, Ring Theory joins the best....The experts will find several attractive and pleasant features in Ring Theory. The most noteworthy is the inclusion, usually in supplements and appendices, of many useful constructions which are hard to locate outside of the original sources....The audience of non
Loring, FH
2014-01-01
Summarising the most novel facts and theories which were coming into prominence at the time, particularly those which had not yet been incorporated into standard textbooks, this important work was first published in 1921. The subjects treated cover a wide range of research that was being conducted into the atom, and include Quantum Theory, the Bohr Theory, the Sommerfield extension of Bohr's work, the Octet Theory and Isotopes, as well as Ionisation Potentials and Solar Phenomena. Because much of the material of Atomic Theories lies on the boundary between experimentally verified fact and spec
Venegas Salgado, Saul; Arredondo Fragoso, Jesus; Ramirez Silva, German; Flores Armenta, Magaly; Ramirez Montes, Miguel [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)]. E-mail: magaly.flores@cfe.gob.mx
2006-07-15
From September through December 2004 a seismic monitoring in the Las Tres Virgenes, BCS, geothermal field was carried out simultaneously with the acid stimulation of wells LV-4 and LV-13. The seismic network had four digital seismographs and recorded 174 local seismic events, 131 regional ones and many more volcanic signals at seismic station TV20 during the acid stimulation. Additionally, 37 seismic events were located, 22 of them inside the most important geothermal zone at depths between 0.4 and 4 km with typically low magnitudes (0.7 to 2.2 Md). Two relevant zones were determined: Zone A related to the El Volcan fault system and Zone B related to injection well LV-8. In Zone A the well-induction stage and the operation start of the wells LV-4 and LV-13 after acidification on October 30 and November 17, 2004, increased seismic activity to a maximum of 12 daily events in early December. When the two wells in Zone B were cooled before the acidification, the seismic events recorded there increased to a maximum of 6 daily events on October 2, and then decreased. Also in Zone B the seismic activity increased after well-induction and the start of well production once they were acidified, recording up to 11 daily events in late November. According to the seismic distribution, we may conclude that the most active fault systems are El Volcan and El Viejo. New proposals for well locations in the field are supported by these results. [Spanish] De septiembre a diciembre de 2004 se realizo un estudio de monitoreo sismico en el campo geotermico de Las Tres Virgenes, BCS, simultaneamente con las estimulaciones acidas de los pozos LV-4 y LV-13. Se utilizo una red sismica conformada por cuatro sismografos digitales, logrando registrar en la estacion sismica TV20 un total de 174 sismos locales, 131 sismos regionales y muchas mas senales de tipo volcanico, durante el periodo del monitoreo de la estimulacion acida. Ademas, se localizaron un total de 37 sismos, de los cuales 22 se
Jaques, Thomas
2010-01-01
Generative Linguistics can and should be engaged by those with an interest in Translation Studies while developing their own positions on literary theory in general, but translation theory in particular. Generative theory provides empirical evidence for a free, creative mind that can comprehend, read, speak and translate a language. What is being proposed here contrasts radically with the dominant position of this generation's Translation Studies specialists, who freely incorporate Post-struc...
Aubin, Jean-Pierre; Saint-Pierre, Patrick
2011-01-01
Viability theory designs and develops mathematical and algorithmic methods for investigating the adaptation to viability constraints of evolutions governed by complex systems under uncertainty that are found in many domains involving living beings, from biological evolution to economics, from environmental sciences to financial markets, from control theory and robotics to cognitive sciences. It involves interdisciplinary investigations spanning fields that have traditionally developed in isolation. The purpose of this book is to present an initiation to applications of viability theory, explai
Sanfilippo, Antonio P.
2005-12-27
Graph theory is a branch of discrete combinatorial mathematics that studies the properties of graphs. The theory was pioneered by the Swiss mathematician Leonhard Euler in the 18th century, commenced its formal development during the second half of the 19th century, and has witnessed substantial growth during the last seventy years, with applications in areas as diverse as engineering, computer science, physics, sociology, chemistry and biology. Graph theory has also had a strong impact in computational linguistics by providing the foundations for the theory of features structures that has emerged as one of the most widely used frameworks for the representation of grammar formalisms.
Hashiguchi, Koichi
2009-01-01
This book details the mathematics and continuum mechanics necessary as a foundation of elastoplasticity theory. It explains physical backgrounds with illustrations and provides descriptions of detailed derivation processes..
Cox, David A
2012-01-01
Praise for the First Edition ". . .will certainly fascinate anyone interested in abstract algebra: a remarkable book!"—Monatshefte fur Mathematik Galois theory is one of the most established topics in mathematics, with historical roots that led to the development of many central concepts in modern algebra, including groups and fields. Covering classic applications of the theory, such as solvability by radicals, geometric constructions, and finite fields, Galois Theory, Second Edition delves into novel topics like Abel’s theory of Abelian equations, casus irreducibili, and the Galo
Manning, Phillip
2011-01-01
The study of quantum theory allowed twentieth-century scientists to examine the world in a new way, one that was filled with uncertainties and probabilities. Further study also led to the development of lasers, the atomic bomb, and the computer. This exciting new book clearly explains quantum theory and its everyday uses in our world.
Hjørland, Birger
2009-01-01
, evaluate and use such systems. Based on "a post-Kuhnian view" of paradigms this paper put forward arguments that the best understanding and classification of theories of concepts is to view and classify them in accordance with epistemological theories (empiricism, rationalism, historicism and pragmatism...
After noting some advantages of using perturbation theory some of the various types are related on a chart and described, including many-body nonlinear summations, quartic force-field fit for geometry, fourth-order correlation approximations, and a survey of some recent work. Alternative initial approximations in perturbation theory are also discussed. 25 references
Liu, Baoding
2015-01-01
When no samples are available to estimate a probability distribution, we have to invite some domain experts to evaluate the belief degree that each event will happen. Perhaps some people think that the belief degree should be modeled by subjective probability or fuzzy set theory. However, it is usually inappropriate because both of them may lead to counterintuitive results in this case. In order to rationally deal with belief degrees, uncertainty theory was founded in 2007 and subsequently studied by many researchers. Nowadays, uncertainty theory has become a branch of axiomatic mathematics for modeling belief degrees. This is an introductory textbook on uncertainty theory, uncertain programming, uncertain statistics, uncertain risk analysis, uncertain reliability analysis, uncertain set, uncertain logic, uncertain inference, uncertain process, uncertain calculus, and uncertain differential equation. This textbook also shows applications of uncertainty theory to scheduling, logistics, networks, data mining, c...
Lukeš, Jaroslav; Netuka, Ivan; Veselý, Jiří
1988-01-01
Within the tradition of meetings devoted to potential theory, a conference on potential theory took place in Prague on 19-24, July 1987. The Conference was organized by the Faculty of Mathematics and Physics, Charles University, with the collaboration of the Institute of Mathematics, Czechoslovak Academy of Sciences, the Department of Mathematics, Czech University of Technology, the Union of Czechoslovak Mathematicians and Physicists, the Czechoslovak Scientific and Technical Society, and supported by IMU. During the Conference, 69 scientific communications from different branches of potential theory were presented; the majority of them are in cluded in the present volume. (Papers based on survey lectures delivered at the Conference, its program as well as a collection of problems from potential theory will appear in a special volume of the Lecture Notes Series published by Springer-Verlag). Topics of these communications truly reflect the vast scope of contemporary potential theory. Some contributions deal...
Kleiss, Ronald H P
1999-01-01
In these lectures I will build up the concept of field theory using the language of Feynman diagrams. As a starting point, field theory in zero spacetime dimensions is used as a vehicle to develop all the necessary techniques: path integral, Feynman diagrams, Schwinger-Dyson equations, asymptotic series, effective action, renormalization etc. The theory is then extended to more dimensions, with emphasis on the combinatorial aspects of the diagrams rather than their particular mathematical structure. The concept of unitarity is used to, finally, arrive at the various Feynman rules in an actual, four-dimensional theory. The concept of gauge-invariance is developed, and the structure of a non-abelian gauge theory is discussed, again on the level of Feynman diagrams and Feynman rules.
Lausen, Berthold; Seidel, Wilfried; Ultsch, Alfred
2010-01-01
Data Analysis, Data Handling and Business Intelligence are research areas at the intersection of computer science, artificial intelligence, mathematics, and statistics. They cover general methods and techniques that can be applied to a vast set of applications such as in marketing, finance, economics, engineering, linguistics, archaeology, musicology, medical science, and biology. This volume contains the revised versions of selected papers presented during the 32nd Annual Conference of the German Classification Society (Gesellschaft für Klassifikation, GfKl). The conference, which was organized in cooperation with the British Classification Society (BCS) and the Dutch/Flemish Classification Society (VOC), was hosted by Helmut-Schmidt-University, Hamburg, Germany, in July 2008.
Reddy, Nallagundla H S; Patnala, Srinivas; Löbenberg, Raimar; Kanfer, Isadore
2014-10-01
Biowaivers are recommended for immediate-release solid oral dosage forms using dissolution testing as a surrogate for in vivo bioequivalence studies. Several guidance are currently available (the World Health Organization (WHO), the US FDA, and the EMEA) where the conditions are described. In this study, definitions, criteria, and methodologies according to the WHO have been applied. The dissolution performances of immediate-release metronidazole, zidovudine, and amoxicillin products purchased in South African and Indian markets were compared to the relevant comparator pharmaceutical product (CPP)/reference product. The dissolution performances were studied using US Pharmacopeia (USP) apparatus 2 (paddle) set at 75 rpm in each of three dissolution media (pH1.2, 4.5, and 6.8). Concentrations of metronidazole, zidovudine, and amoxicillin in each dissolution media were determined by HPLC. Of the 11 metronidazole products tested, only 8 could be considered as very rapidly dissolving products as defined by the WHO, whereas 2 of those products could be considered as rapidly dissolving products but did not comply with the f 2 acceptance criteria in pH 6.8. All 11 zidovudine products were very rapidly dissolving, whereas in the case of the 14 amoxicillin products tested, none of those products met any of the WHO criteria. This study indicates that not all generic products containing the same biopharmaceutics classification system (BCS) I drug and in similar strength and dosage form are necessarily in vitro equivalent. Hence, there is a need for ongoing market surveillance to determine whether marketed generic products containing BCS I drugs meet the release requirements to confirm their in vitro bioequivalence to the respective reference product. PMID:24848760
Bohm, David
1951-01-01
This superb text by David Bohm, formerly Princeton University and Emeritus Professor of Theoretical Physics at Birkbeck College, University of London, provides a formulation of the quantum theory in terms of qualitative and imaginative concepts that have evolved outside and beyond classical theory. Although it presents the main ideas of quantum theory essentially in nonmathematical terms, it follows these with a broad range of specific applications that are worked out in considerable mathematical detail. Addressed primarily to advanced undergraduate students, the text begins with a study of t
Lubliner, Jacob
2008-01-01
The aim of Plasticity Theory is to provide a comprehensive introduction to the contemporary state of knowledge in basic plasticity theory and to its applications. It treats several areas not commonly found between the covers of a single book: the physics of plasticity, constitutive theory, dynamic plasticity, large-deformation plasticity, and numerical methods, in addition to a representative survey of problems treated by classical methods, such as elastic-plastic problems, plane plastic flow, and limit analysis; the problem discussed come from areas of interest to mechanical, structural, and
Andrews, George E
1994-01-01
Although mathematics majors are usually conversant with number theory by the time they have completed a course in abstract algebra, other undergraduates, especially those in education and the liberal arts, often need a more basic introduction to the topic.In this book the author solves the problem of maintaining the interest of students at both levels by offering a combinatorial approach to elementary number theory. In studying number theory from such a perspective, mathematics majors are spared repetition and provided with new insights, while other students benefit from the consequent simpl
Victor, Oluwafemi Oludu
2015-01-01
From ages to ages there had been expectation of individuals on a specific predictions and future occurrences. So also in a game, different participant that involves in those specified game have their various expectations of the results or the output of the game they are involved in. That is why we need a mathematical theory that helps in prediction of the future expectations in our day to day activities. Therefore the Martingale Theory is a very good theory that explains and dissects the expe...
Shah, Vinod P; Amidon, Gordon L
2014-09-01
The Biopharmaceutics Classification System (BCS) has become widely accepted today in the academic, industrial, and regulatory world. While the initial application of the BCS was to regulatory science bioequivalence (BE) issues and related implications, it has come to be utilized widely by the pharmaceutical industry in drug discovery and development as well. This brief manuscript will relate the story of the BCS development. While much of the ground work for the BCS goes back to the pharmacokinetic and drug absorption research by Gordon Amidon (GLA) in the 1970s and 1980s, the realization of the need for a classification or categorization of drug and drug products for setting dissolution standards became apparent to GLA during his 1990-1991 sabbatical year at the FDA. Initiated at the invitation of the then CEDR director, Dr. Carl Peck, to become a visiting scientist at the FDA, the goal was to promote regulatory research at the FDA, in my case, in biopharmaceutics, and to develop a science-based system to simplify regulatory requirements. PMID:24961917
This report discusses concepts in nuclear theory such as: neutrino nucleosynthesis; double beta decay; neutrino oscillations; chiral symmetry breaking; T invariance; quark propagator; cold fusion; and other related topics
Hodges, Wilfrid
1993-01-01
An up-to-date and integrated introduction to model theory, designed to be used for graduate courses (for students who are familiar with first-order logic), and as a reference for more experienced logicians and mathematicians.
Nel, Louis
2016-01-01
This book presents a detailed, self-contained theory of continuous mappings. It is mainly addressed to students who have already studied these mappings in the setting of metric spaces, as well as multidimensional differential calculus. The needed background facts about sets, metric spaces and linear algebra are developed in detail, so as to provide a seamless transition between students' previous studies and new material. In view of its many novel features, this book will be of interest also to mature readers who have studied continuous mappings from the subject's classical texts and wish to become acquainted with a new approach. The theory of continuous mappings serves as infrastructure for more specialized mathematical theories like differential equations, integral equations, operator theory, dynamical systems, global analysis, topological groups, topological rings and many more. In light of the centrality of the topic, a book of this kind fits a variety of applications, especially those that contribute to ...
A series of lectures on plasma theory with the main headings: introduction; charged particles moving in em fields; the liquid model; transport phenomena in the plasma; wave propagation in plasmas; plasma instabilities. 57 figs. (qui)
Gould, Ronald
2012-01-01
This introduction to graph theory focuses on well-established topics, covering primary techniques and including both algorithmic and theoretical problems. The algorithms are presented with a minimum of advanced data structures and programming details. This thoroughly corrected 1988 edition provides insights to computer scientists as well as advanced undergraduates and graduate students of topology, algebra, and matrix theory. Fundamental concepts and notation and elementary properties and operations are the first subjects, followed by examinations of paths and searching, trees, and networks. S
Murdin, P.
2000-11-01
A theory based on the premise that, on the microscopic scale, physical quantities have discrete, rather than a continuous range of, values. The theory was devised in the early part of the twentieth century to account for certain phenomena that could not be explained by classical physics. In 1900, the German physicist, Max Planck (1858-1947), was able precisely to describe the previously unexplaine...
Effective theories of universal theories
Wells, James D.; Zhang, Zhengkang
2016-01-01
It is well-known but sometimes overlooked that constraints on the oblique parameters (most notably S and T parameters) are generally speaking only applicable to a special class of new physics scenarios known as universal theories. In the effective field theory (EFT) framework, the oblique parameters should not be associated with Wilson coefficients in a particular operator basis, unless restrictions have been imposed on the EFT so that it describes universal theories. We work out these restrictions, and present a detailed EFT analysis of universal theories. We find that at the dimension-6 level, universal theories are completely characterized by 16 parameters. They are conveniently chosen to be: 5 oblique parameters that agree with the commonly-adopted ones, 4 anomalous triple-gauge couplings, 3 rescaling factors for the h 3, hf f , hV V vertices, 3 parameters for hV V vertices absent in the Standard Model, and 1 four-fermion coupling of order y f 2 . All these parameters are defined in an unambiguous and basis-independent way, allowing for consistent constraints on the universal theories parameter space from precision electroweak and Higgs data.
Possibility Theory versus Probability Theory in Fuzzy Measure Theory
Parul Agarwal
2015-05-01
Full Text Available The purpose of this paper is to compare probability theory with possibility theory, and to use this comparison in comparing probability theory with fuzzy set theory. The best way of comparing probabilistic and possibilistic conceptualizations of uncertainty is to examine the two theories from a broader perspective. Such a perspective is offered by evidence theory, within which probability theory and possibility theory are recognized as special branches. While the various characteristic of possibility theory within the broader framework of evidence theory are expounded in this paper, we need to introduce their probabilistic counterparts to facilitate our discussion.
Carroll, Joseph; Clasen, Mathias; Jonsson, Emelie;
2015-01-01
Biocultural theory is an integrative research program designed to investigate the causal interactions between biological adaptations and cultural constructions. From the biocultural perspective, cultural processes are rooted in the biological necessities of the human life cycle: specifically human...... ideological beliefs, and artistic practices such as music, dance, painting, and storytelling. Establishing biocultural theory as a program that self-consciously encompasses the different particular forms of human evolutionary research could help scholars and scientists envision their own specialized areas of...... research as contributions to a coherent, collective research program. This article argues that a mature biocultural paradigm needs to be informed by at least 7 major research clusters: (a) gene-culture coevolution; (b) human life history theory; (c) evolutionary social psychology; (d) anthropological...
Viggiano Guerra, J.C.; Sandoval Medina, F.; Flores Armenta, M.C. [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)]. E-mail: fernando.sandoval@cfe.gob.mx, E-mail: magaly.flores@cfe.gob.mx; Perez, R.J. [Universidad de Calgary (Canada); Gonzalez Partida, E. [Universidad Nacional Autonoma de Mexico, Centro de Geociencias, Mexico, D.F. (Mexico)
2009-01-15
SPCALC is an excellent software application providing chemical and multi-phase speciation for geothermal fluids. Recently it was acquired by the Comision Federal de Electricidad (CFE) through a contract with the National Autonomous University of Mexico (UNAM) and the University of Calgary, Canada. Software methodology consists of calculating thermodynamic variables, such as activity (a) and fugacity (f) of chemical species, as well as the saturation indices (log Q/K) of mineral phases of the reservoir. In other words, it models the thermodynamic conditions of the reservoir (pH among other) and simulates the fluid-corrosion rate. This allows the software to foresee scaling and corrosion. In this paper, pervasive fluids in Cretaceous granitic rocks penetrated by wells LV-4A, LV-11 and LV-13 in Las Tres Virgenes geothermal field, BCS, are modeled, starting with chemical analyses. The more important ratios among activities [those which influence the fluid-rock interaction (i.e. {sup a}K{sup +}/{sup a}H{sup +}, {sup a}Ca{sup ++}/{sup a}H{sup +}, {sup a}Na{sup +}/{sup a}H{sup +}, {sup a}Mg{sup ++}/{sup a}H{sup +}) and whose results are the minerals visible under a microscope] are graphed in balance diagrams compatible with the pressure (P) and temperature (T) conditions in the reservoir. Epidote (zoisite) is the mineral found in congruent equilibrium with the system. The main mineral association at those conditions (200-250 degrees Celsius and {approx}18 bar), as observed in the well cuttings, is calcite+illite-quartz{+-}epidote, which is explained by the hydrolithic reactions that form replacement calcite in the presence of CO{sub 2}, thus restricting the formation of epidote and eventually eliminating it. The process enhances the CO{sub 2} molarity in the residual fluid, even up to {sup m}CO{sub 2} 1, which means the CO{sub 2} can be diluted back into fluid and intervene again in the process of calcite formation (2HCO{sub 3}{sup -} + Ca{sup ++} = calcite + H{sub 2}O
Stewart, Ian
2003-01-01
Ian Stewart's Galois Theory has been in print for 30 years. Resoundingly popular, it still serves its purpose exceedingly well. Yet mathematics education has changed considerably since 1973, when theory took precedence over examples, and the time has come to bring this presentation in line with more modern approaches.To this end, the story now begins with polynomials over the complex numbers, and the central quest is to understand when such polynomials have solutions that can be expressed by radicals. Reorganization of the material places the concrete before the abstract, thus motivating the g
This textbook for students of physics is oriented in the selection of matter by the contents of a two-semester course about quantum theory. Thereby the foundations of quantum theory, among them the quantum-mechanical measurement process, the mathematical formalism, and Bell's inequalities, are extensively treated. Also modern concepts like feynman's path integral are regarded. This work is equally suited for a self-study, as course-accompanying lecture, and for preparations of examina. Application examples, supplementary explanations, and numerous illustration take car for a good understanding of the theoretical contents
Effective theories of universal theories
Wells, James D
2015-01-01
It is well-known but sometimes overlooked that constraints on the oblique parameters (most notably $S$ and $T$ parameters) are only applicable to a special class of new physics scenarios known as universal theories. In the effective field theory (EFT) framework, the oblique parameters should not be associated with Wilson coefficients in a particular operator basis, unless restrictions have been imposed on the EFT so that it describes universal theories. We work out these restrictions, and present a detailed EFT analysis of universal theories. We find that at the dimension-6 level, universal theories are completely characterized by 16 parameters. They are conveniently chosen to be: 5 oblique parameters that agree with the commonly-adopted ones, 4 anomalous triple-gauge couplings, 3 rescaling factors for the $h^3$, $hff$, $hVV$ vertices, 3 parameters for $hVV$ vertices absent in the Standard Model, and 1 four-fermion coupling of order $y_f^2$. All these parameters are defined in an unambiguous and basis-indepen...
This is a summary of the advances in magnetic fusion energy theory research presented at the 17th International Atomic Energy Agency Fusion Energy Conference from 19 24 October, 1998 in Yokohama, Japan. Theory and simulation results from this conference provided encouraging evidence of significant progress in understanding the physics of thermonuclear plasmas. Indeed, the grand challenge for this field is to acquire the basic understanding that can readily enable the innovations which would make fusion energy practical. In this sense, research in fusion energy is increasingly able to be categorized as fitting well the 'Pasteur's Quadrant' paradigm, where the research strongly couples basic science ('Bohr's Quadrant') to technological impact ('Edison's Quadrant'). As supported by some of the work presented at this conference, this trend will be further enhanced by advanced simulations. Eventually, realistic three-dimensional modeling capabilities, when properly combined with rapid and complete data interpretation of results from both experiments and simulations, can contribute to a greatly enhanced cycle of understanding and innovation. Plasma science theory and simulation have provided reliable foundations for this improved modeling capability, and the exciting advances in high-performance computational resources have further accelerated progress. There were 68 papers presented at this conference in the area of magnetic fusion energy theory
Monthoux, Pierre Guillet de; Statler, Matt
2014-01-01
The recent Carnegie report (Colby, et al., 2011) characterizes the goal of business education as the development of practical wisdom. In this chapter, the authors reframe Scharmer’s Theory U as an attempt to develop practical wisdom by applying certain European philosophical concepts. Specifically...
Written by the author of the widely acclaimed textbook. Theoretical Atomic Physics Includes sections on quantum reflection, tunable Feshbach resonances and Efimov states. Useful for advanced students and researchers. This book presents a concise and modern coverage of scattering theory. It is motivated by the fact that experimental advances have shifted and broadened the scope of applications where concepts from scattering theory are used, e.g. to the field of ultracold atoms and molecules, which has been experiencing enormous growth in recent years, largely triggered by the successful realization of Bose-Einstein condensates of dilute atomic gases in 1995. In the present treatment, special attention is given to the role played by the long-range behaviour of the projectile-target interaction, and a theory is developed, which is well suited to describe near-threshold bound and continuum states in realistic binary systems such as diatomic molecules or molecular ions. The level of abstraction is kept as low as at all possible, and deeper questions related to mathematical foundations of scattering theory are passed by. The book should be understandable for anyone with a basic knowledge of nonrelativistic quantum mechanics. It is intended for advanced students and researchers, and it is hoped that it will be useful for theorists and experimentalists alike.
Hall, Marshall
2011-01-01
Includes proof of van der Waerden's 1926 conjecture on permanents, Wilson's theorem on asymptotic existence, and other developments in combinatorics since 1967. Also covers coding theory and its important connection with designs, problems of enumeration, and partition. Presents fundamentals in addition to latest advances, with illustrative problems at the end of each chapter. Enlarged appendixes include a longer list of block designs.
Smith, Shelley
This paper came about within the context of a 13-month research project, Focus Area 1 - Method and Theory, at the Center for Public Space Research at the Royal Academy of the Arts School of Architecture in Copenhagen, Denmark. This project has been funded by RealDania. The goals of the research p...
Plummer, MD
1986-01-01
This study of matching theory deals with bipartite matching, network flows, and presents fundamental results for the non-bipartite case. It goes on to study elementary bipartite graphs and elementary graphs in general. Further discussed are 2-matchings, general matching problems as linear programs, the Edmonds Matching Algorithm (and other algorithmic approaches), f-factors and vertex packing.
The text book composed of five parts, which are summary of this book, arrangement of electricity theory including electricity nad magnetism, a direct current, and alternating current. It has two dictionary electricity terms for a synonym. The last is an appendix. It is for preparing for test of officer, electricity engineer and fire fighting engineer.