633 research outputs found

    Potentials with Two Shifted Sets of Equally Spaced Eigenvalues and Their Calogero Spectrum

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    Motivated by the concept of shape invariance in supersymmetric quantum mechanics, we obtain potentials whose spectrum consists of two shifted sets of equally spaced energy levels. These potentials are similar to the Calogero-Sutherland model except the singular term αx−2\alpha x^{-2} always falls in the transition region −1/4<α<3/4-1/4 < \alpha < 3/4 and there is a delta-function singularity at x=0.Comment: Latex, 12 pages, Figures available from Authors, To appear in Physics Letters A. Please send requests for figures to [email protected] or [email protected]

    Methods for Generating Quasi-Exactly Solvable Potentials

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    We describe three different methods for generating quasi-exactly solvable potentials, for which a finite number of eigenstates are analytically known. The three methods are respectively based on (i) a polynomial ansatz for wave functions; (ii) point canonical transformations; (iii) supersymmetric quantum mechanics. The methods are rather general and give considerably richer results than those available in the current literature.Comment: 12 pages, LaTe

    Non-Central Potentials and Spherical Harmonics Using Supersymmetry and Shape Invariance

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    It is shown that the operator methods of supersymmetric quantum mechanics and the concept of shape invariance can profitably be used to derive properties of spherical harmonics in a simple way. The same operator techniques can also be applied to several problems with non-central vector and scalar potentials. As examples, we analyze the bound state spectra of an electron in a Coulomb plus an Aharonov-Bohm field and/or in the magnetic field of a Dirac monopole.Comment: Latex, 12 pages. To appear in American Journal of Physic

    The Egr transcription factor family: From signal transduction to kidney differentiation

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    Extracellular “signals” in the form of neurotransmitters, growth factors, hormones, and matrix are known to be key modulators of cellular phenotype. These agents lead to the generation of second messenger signals in the plasma membrane and cytosol. In turn, these biochemical events modulate the expression of a set of so-called immediate-early genes (IEG), whose induction does not require de novo protein synthesis. Several years ago, we and others identified several IEGs [reviewed in 1 and 2]. Of particular interest to our laboratory has been a subset of IEGs that encode transcription factors, since as such they might: (1) be the targets for second messenger events, and (2) activate or repress the transcription of critical genes required to effect a particular cellular phenotype. Thus, immediate-early transcription factors (IETF) should couple short-term responses in the form of second messenger events to long-term changes in gene expression instrumental in altering phenotype

    Incidence of protein deficiency in relation to different diets in India

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    1. A method is presented for estimating the incidence of protein deficiency which takes due note of the association of protein deficiency with inadequate calorie intake and is applied to the data from dietary surveys in India. It is concluded that in only about one out of ten cases does protein deficiency occur as a direct result of inadequate protein intake. In the vast majority of cases protein deficiency is the result of inadequate intake of total energy. Protein which does not bring calories with it is therefore unlikely to make any significant contribution to the solution of the protein problem in India. 2. It is shown that diets based on cereals and pulses normally consumed by the people can meet man's needs for proteinat all ages provided enough food is taken to satisfy his energy needs. It is, however, important to ensure for infants a smooth transition from breast milk to solid diets. Special care is also necessary in the case of pregnant and lactating women. 3. The nature of protein deficiency is discussed in relation to different dietary patterns. The continuity implied in the bivariate distributions of calorie and protein intake is seen to provide a possible explanation of the experimental results on the development of kwashiorkor observed in animals on a diet short of both calories and protein and ondietspredominantly short of protein
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