Anisotropy of effective masses in CuInSe2

Anisotropy of the valence band is experimentally demonstrated in CuInSe2, a key component of the absorber layer in one of the leading thin-film solar cell technology. By changing the orientation of applied magnetic fields with respect to the crystal lattice, we measure considerable differences in the diamagnetic shifts and effective g-factors for the A and B free excitons. The resulting free exciton reduced masses are combined with a perturbation model for non-degenerate independent excitons and theoretical dielectric constants to provide the anisotropic effective hole masses, revealing anisotropies of 5.5 (4.2) for the A (B) valence bands

Calcium channel β subunits differentially modulate recovery of the channel from inactivation

AbstractWe examined the effects of calcium channel β subunits upon the recovery from inactivation of α1 subunits expressed in Xenopus oocytes. Recovery of the current carried by the L-type α1 subunit (cyCav1) from the jellyfish Cyanea capillata was accelerated by coexpression of any β subunit, but the degree of potentiation differed according to which β isoform was coexpressed. The Cyanea β subunit was most effective, followed by the mammalian b3, b4, and β2a subtypes. Recovery of the human Cav2.3 subunit was also modulated by β subunits, but was slowed instead. β3 was the most potent subunit tested, followed by β4, then β2a, which had virtually no effect. These results demonstrate that different β subunit isoforms can affect recovery of the channel to varying degrees, and provide an additional mechanism by which β subunits can differentially regulate α1 subunits

Bio-based sustainable aerogels: New sensation in CO2 capture

Bio-based aerogels with customizable porosities and functionalities constitute significant potential for CO2 capture. Developing bio-based aerogels from different polysaccharides and proteins is a safe, economical, and environmentally sustainable approach. Polysaccharides are biodegradable, sustainable, renewable, and plentiful in nature. Because of these advantages, the use of bio-based aerogels with porosity and amine functionality has attracted considerable interest. In this review we have discussed the recent development in the synthesis of bio-based aerogels and their application in CO2 capture

Quantum Mass and Central Charge of Supersymmetric Monopoles - Anomalies, current renormalization, and surface terms

We calculate the one-loop quantum corrections to the mass and central charge of N=2 and N=4 supersymmetric monopoles in 3+1 dimensions. The corrections to the N=2 central charge are finite and due to an anomaly in the conformal central charge current, but they cancel for the N=4 monopole. For the quantum corrections to the mass we start with the integral over the expectation value of the Hamiltonian density, which we show to consist of a bulk contribution which is given by the familiar sum over zero-point energies, as well as surface terms which contribute nontrivially in the monopole sector. The bulk contribution is evaluated through index theorems and found to be nonvanishing only in the N=2 case. The contributions from the surface terms in the Hamiltonian are cancelled by infinite composite operator counterterms in the N=4 case, forming a multiplet of improvement terms. These counterterms are also needed for the renormalization of the central charge. However, in the N=2 case they cancel, and both the improved and the unimproved current multiplet are finite.Comment: 1+40 pages, JHEP style. v2: small corrections and additions, references adde

Strong and auxiliary forms of the semi-Lagrangian method for incompressible flows

We present a review of the semi-Lagrangian method for advection-diusion and incompressible Navier-Stokes equations discretized with high-order methods. In particular, we compare the strong form where the departure points are computed directly via backwards integration with the auxiliary form where an auxiliary advection equation is solved instead; the latter is also referred to as Operator Integration Factor Splitting (OIFS) scheme. For intermediate size of time steps the auxiliary form is preferrable but for large time steps only the strong form is stable

Scattering Theory Approach to Random Schroedinger Operators in One Dimension

Methods from scattering theory are introduced to analyze random Schroedinger operators in one dimension by applying a volume cutoff to the potential. The key ingredient is the Lifshitz-Krein spectral shift function, which is related to the scattering phase by the theorem of Birman and Krein. The spectral shift density is defined as the "thermodynamic limit" of the spectral shift function per unit length of the interaction region. This density is shown to be equal to the difference of the densities of states for the free and the interacting Hamiltonians. Based on this construction, we give a new proof of the Thouless formula. We provide a prescription how to obtain the Lyapunov exponent from the scattering matrix, which suggest a way how to extend this notion to the higher dimensional case. This prescription also allows a characterization of those energies which have vanishing Lyapunov exponent.Comment: 1 figur

A solution of a problem of Sophus Lie: Normal forms of 2-dim metrics admitting two projective vector fields

We give a complete list of normal forms for the 2-dimensional metrics that admit a transitive Lie pseudogroup of geodesic-preserving transformations and we show that these normal forms are mutually non-isometric. This solves a problem posed by Sophus Lie.Comment: This is an extended version of the paper that will appear in Math. Annalen. Some typos were corrected, references were updated, title was changed (as in the journal version). 31 page

Meromorphic traveling wave solutions of the complex cubic-quintic Ginzburg-Landau equation

We look for singlevalued solutions of the squared modulus M of the traveling wave reduction of the complex cubic-quintic Ginzburg-Landau equation. Using Clunie's lemma, we first prove that any meromorphic solution M is necessarily elliptic or degenerate elliptic. We then give the two canonical decompositions of the new elliptic solution recently obtained by the subequation method.Comment: 14 pages, no figure, to appear, Acta Applicandae Mathematica

Moving for Employment Reasons

While most models of population migration assume that members of the labour force migrate to enhance returns to their labour, major surveys in the USA (PSID and CPS), in the UK (BHPS) and Australia (HILDA) all show that only around 10 percent of all individuals who change residence are motivated primarily by employment reasons. Of those moving between local labour markets only about 30 percent say they are motivated by employment reasons. We explore this apparent paradox by drawing on evidence from the Dynamics of Motivation and Migration Survey (DMM), which recorded the reasons people of working age, changed their permanent residence in New Zealand over the two-year period 2005 and 2006. The need to solve the employment problem before moving means that reasons offered retrospectively for moving usually reflect a wish to adjust consumption even in the case of those moving between local labour markets. For most people of working age employment remains a necessary condition rather than sufficient reason for moving and this is why the pattern of net flows among local markets appear to support theories of migration change even though few people say they move for employment reasons

Phase of the Wilson Line at High Temperature in the Standard Model

We compute the effective potential for the phase of the Wilson line at high temperature in the standard model to one loop order. Besides the trivial vacua, there are metastable states in the direction of $U(1)$ hypercharge. Assuming that the universe starts out in such a metastable state at the Planck scale, it easily persists to the time of the electroweak phase transition, which then proceeds by an unusual mechanism. All remnants of the metastable state evaporate about the time of the $QCD$ phase transition.Comment: 4 pages in ReVTeX plus 1 figure; Columbia Univ. preprint CU-TP-63