Transient natural convection flows in closed containers technical report no. 2

Measurements and calculations of natural flow convection and thermal stratification in closed container

Transient, laminar, free-convection heat and mass transfer in closed, partially filled, liquid containers technical report no. 1

Two-dimensional, laminar, transient, natural- convection heat and mass transfer in closed, partially filled liquid container

Presentation of the Child with Renal Disease and Guidelines for Referral to the Pediatric Nephrologist

Renal disease is a major cause of morbidity and mortality. Pediatric patients with renal disease, especially younger ones may present with nonspecific signs and symptoms unrelated to the urinary tract. Pediatricians, therefore, should be familiar with the modes of presentation of renal disease and should have a high index of suspicion of these conditions. Affected patients may present with signs and symptoms of the disease, abnormal urinalysis, urinary tract infection, electrolyte and acid-base abnormalities, decreased renal function, renal involvement in systemic disease, glomerular and renal tubular diseases, congenital abnormalities, and hypertension. Pediatricians may initiate evaluation of renal disease to the extent that they feel comfortable with. The role of the pediatrician in the management of the child with renal disease and guidelines for patient referral to the pediatric nephrologist are presented

Homalg: A meta-package for homological algebra

The central notion of this work is that of a functor between categories of finitely presented modules over so-called computable rings, i.e. rings R where one can algorithmically solve inhomogeneous linear equations with coefficients in R. The paper describes a way allowing one to realize such functors, e.g. Hom, tensor product, Ext, Tor, as a mathematical object in a computer algebra system. Once this is achieved, one can compose and derive functors and even iterate this process without the need of any specific knowledge of these functors. These ideas are realized in the ring independent package homalg. It is designed to extend any computer algebra software implementing the arithmetics of a computable ring R, as soon as the latter contains algorithms to solve inhomogeneous linear equations with coefficients in R. Beside explaining how this suffices, the paper describes the nature of the extensions provided by homalg.Comment: clarified some points, added references and more interesting example

Credit where credit is due: an approach to education returns based on Shapley values

We propose the use of methods based on the Shapley value to assess the fact that private returns to lower levels of educational attainment should be credited with part of the returns from higher attainment levels, since achieving primary education is a necessary condition to enter secondary and tertiary educational levels. We apply the proposed adjustment to a global dataset of private returns to different educational attainment levels and find that the corrected returns to education imply a large shift of returns from tertiary to primary schooling in countries at all income levels

Exact solutions for vibrational levels of the Morse potential via the asymptotic iteration method

Exact solutions for vibrational levels of diatomic molecules via the Morse potential are obtained by means of the asymptotic iteration method. It is shown that, the numerical results for the energy eigenvalues of $^{7}Li_{2}$ are all in excellent agreement with the ones obtained before. Without any loss of generality, other states and molecules could be treated in a similar way

Polarization of tightly focused laser beams

The polarization properties of monochromatic light beams are studied. In contrast to the idealization of an electromagnetic plane wave, finite beams which are everywhere linearly polarized in the same direction do not exist. Neither do beams which are everywhere circularly polarized in a fixed plane. It is also shown that transversely finite beams cannot be purely transverse in both their electric and magnetic vectors, and that their electromagnetic energy travels at less than c. The electric and magnetic fields in an electromagnetic beam have different polarization properties in general, but there exists a class of steady beams in which the electric and magnetic polarizations are the same (and in which energy density and energy flux are independent of time). Examples are given of exactly and approximately linearly polarized beams, and of approximately circularly polarized beams.Comment: 9 pages, 6 figure

Invariant indices of polarimetric purity. Generalized indices of purity for nxn covariance matrices

A proper set of indices characterizing the polarimetric purity of light and material media is defined from the eigenvalues of the corresponding coherency matrix. A simple and generalizable relation of these indices with the current parameters characterizing the global purity is obtained. A general definition for systems characterized by nxn positive semidefinite Hermitian matrices is introduced in terms of the corresponding eigenvalues and diagonal Gell-Mann matrices. The set of n-1 indices of purity has a nested structure and provide complete information about the statistical purity of the system.Comment: 19 pages, 2 figure