Magnetic field generation by pointwise zero-helicity three-dimensional steady flow of incompressible electrically conducting fluid

We introduce six families of three-dimensional space-periodic steady solenoidal flows, whose kinetic helicity density is zero at any point. Four families are analytically defined. Flows in four families have zero helicity spectrum. Sample flows from five families are used to demonstrate numerically that neither zero kinetic helicity density, nor zero helicity spectrum prohibit generation of large-scale magnetic field by the two most prominent dynamo mechanisms: the magnetic $\alpha$-effect and negative eddy diffusivity. Our computations also attest that such flows often generate small-scale field for sufficiently small magnetic molecular diffusivity. These findings indicate that kinetic helicity and helicity spectrum are not the quantities controlling the dynamo properties of a flow regardless of whether scale separation is present or not.Comment: 37 pages, 11 figures, 54 reference

Estrategias de redes de apoyo en el proceso de inserción laboral por parte de mujeres en condición sola con hijos(as) menores de 12 años de edad, pertenecientes a la escuela Enrique Cárdenas, Reñaca Alto, Viña del Mar

Tesis (Trabajo Social)Este proyecto de investigación trata sobre las redes de apoyo que articulan las madres en condición sola con hijos dependientes menores de 12 años, para permitir su inserción laboral. Específicamente se analiza la forma cómo se estructuran las redes de acuerdo a sus diferentes categorías como las redes familiares, de amistades y gubernamentales principalmente. Se encontró que en Chile estas mujeres reciben importantes ayudas para cumplir con sus diferentes roles como madres jefas de hogar de parte de los programas de gobierno, lo que se complementa con la gestión que cada una desarrolla de modo personal, lo que resulta muy importante para garantizar el bienestar y la calidad de vida de su familia. Al respecto se ha observado que estas madres en situación sola si reciben colaboración de las diferentes redes, lo cual implica que ellas deben saber tomar decisiones para elegir lo más conveniente, dada su condición particular de vulnerabilidad al carecer de la compañía del padre de sus hijos y de recursos económicos suficientes. Por este motivo deben orientar, sostener y articular sus redes de apoyo familiar, comunitario e institucional facilitando su participación en el mercado laboral. Actualmente en Chile existe un aumento en la inserción laboral femenina general, sin embargo también se presenta una fuerte exclusión del mercado laboral de los segmentos menos calificados, por lo cual se ven obligadas a desarrollar diferentes actividades en el mercado informal, en este contexto cada red cumple con una función específica para contribuir al desarrollo de este tipo de familia

Modifications to the Machine Optics of BESSY II Necessitated by the EMIL Project

The Helmholtz Zentrum Berlin and the Max Planck Society are going to build a new dedicated X ray beam line at the synchrotron light source BESSY II which will be used for analyzing materials for renewable energy generation. The new large scale project has been dubbed EMIL. In this document we present the modifications to the machine optics and to what extent these changes affect the performance of BESSY I

Charges of Exceptionally Twisted Branes

The charges of the exceptionally twisted (D4 with triality and E6 with charge conjugation) D-branes of WZW models are determined from the microscopic/CFT point of view. The branes are labeled by twisted representations of the affine algebra, and their charge is determined to be the ground state multiplicity of the twisted representation. It is explicitly shown using Lie theory that the charge groups of these twisted branes are the same as those of the untwisted ones, confirming the macroscopic K-theoretic calculation. A key ingredient in our proof is that, surprisingly, the G2 and F4 Weyl dimensions see the simple currents of A2 and D4, respectively.Comment: 19 pages, 2 figures, LaTex2e, complete proofs of all statements, updated bibliograph

The charges of a twisted brane

The charges of the twisted D-branes of certain WZW models are determined. The twisted D-branes are labelled by twisted representations of the affine algebra, and their charge is simply the ground state multiplicity of the twisted representation. It is shown that the resulting charge group is isomorphic to the charge group of the untwisted branes, as had been anticipated from a K-theory calculation. Our arguments rely on a number of non-trivial Lie theoretic identities.Comment: 27 pages, 1 figure, harvmac (b

Max Schottelius : Pioneer in Pheochromocytoma

First descriptions of diseases attract tremendous interest because they reveal scientific insight even in retrospect. Max Schottelius, the pathologist contributing the first histological description of pheochromocytoma, remains anonymous. We reviewed the description by Schottelius and weighed the report in modern context. Schottelius described the classical diagnostic elements of pheochromocytoma, including the brown appearance after exposure to chromate-containing Mueller's fixative. This color change, known as chromaffin reaction, results fromoxidation of catecholamines and is reflected in the name pheochromocytoma, meaning dusky-colored chromate-positive tumor. Thus Schottelius performed the first known histochemical contribution to diagnosis, which is today standard with immunohistochemistry for chromogranin. Copyright (c) 2017 Endocrine Society This article has been published under the terms of the Creative Commons Attribution NonCommercial, No-Derivatives License (CC BY-NC-ND).Peer reviewe

D-brane charges on non-simply connected groups

The maximally symmetric D-branes of string theory on the non-simply connected Lie group SU(n)/Z_d are analysed using conformal field theory methods, and their charges are determined. Unlike the well understood case for simply connected groups, the charge equations do not determine the charges uniquely, and the charge group associated to these D-branes is therefore in general not cyclic. The precise structure of the charge group depends on some number theoretic properties of n, d, and the level of the underlying affine algebra k. The examples of SO(3)=SU(2)/Z_2 and SU(3)/Z_3 are worked out in detail, and the charge groups for SU(n)/Z_d at most levels k are determined explicitly.Comment: 31 pages, 1 figure. 2 refs added. Added the observation: the charge group for each su(2) theory equals the centre of corresponding A-D-E grou

D-brane charges on SO(3)

In this letter we discuss charges of D-branes on the group manifold SO(3). Our discussion will be based on a conformal field theory analysis of boundary states in a Z_2-orbifold of SU(2). This orbifold differs from the one recently discussed by Gaberdiel and Gannon in its action on the fermions and leads to a drastically different charge group. We shall consider maximally symmetric branes as well as branes with less symmetry, and find perfect agreement with a recent computation of the corresponding K-theory groups.Comment: 11 pages, 1 figure. Some comments adde