Matter sound waves in two-component Bose-Einstein condensates

The creation and propagation of sound waves in two-component Bose-Einstein condensates (BEC) are investigated and a new method of wave generation in binary BEC mixtures is proposed. The method is based on a fast change of the inter-species interaction constant and is illustrated for two experimental settings: a drop-like condensate immersed into a second large repulsive condensate, and a binary mixture of two homogeneous repulsive BEC's. A mathematical model based on the linearized coupled Gross-Pitaevskii equations is developed and explicit formulae for the space and time dependence of sound waves are provided. Comparison of the analytical and numerical results shows excellent agreement, confirming the validity of the proposed approach.Comment: 16 pages, 9 figure

Pegmatitas en materiales metamórficos del norte de la provincia de Córdoba. Mineralogía y posibilidades económicas

[Resumen] En relación con rocas metamórficas de edad Precámbrica y metamorfismo de grado medio-alto se han estudiado más de 60 masas de pegmatitas cuarzo-feldespáticas compuestas por cuarzo, feldespato potásico, albita, moscovita, turma1 ina, granate, biotita, menas metálicas, minerales de uranio y otros. Las masas pegmatíticas son de formas irregulares o 1entejonares subconcordantes con la esquistosidad regional más manifiesta. Sus dimensiones oscilan entre unos decímetros y decenas de metros, y su continuidad lateral su pera en algunos casos los trescientos metros. Considerando sólo las masas de potencia métrica, por sus reservas, cal idad química de sus principales especies minerales, tamaño de grano, texturas, etc. es planteable la obtención industrial de cuarzo, feldespato potásico, feldespato sódico y moscovita[Abstract] More than 60 outcrops of quartz-fe1despatic pagmatites have been studied re1ated with Precambrian metamorphic rocks of medium-high grade. The pagmatites are composed of quartz, potash fe1dspar, a1bite, muscovite, turma1 ine, garnet, biotite, ores, uranium minerals and others. The pegmatite outcrops hare irregular o lenticular forms, subparallell to the main regional schistosity. They vary in size between a few decimeters to some tens of meters, whi1e su lateral continuity exceed in sorne cases 300 meterse By taking into account on1y the outcrop of metric size, their stocks, chemica1 qual ity of the main mineral species, grain size, texture, etc., it can be planned the industrial recovery of quartz, potash feldspar, sodic fe1dspar and muscovit

Principales componentes químicos y parámetros físicos del queso de Los Pedroches

Se ha determinado la composición química bruta, los principales componentes mmerales y dos parámetros físicos, el pH y la ow, de un lote heterogéneo de 16 quesos de Los Pedroches maduros, elaborados todos eUos por productores diferentes. Los valores medios hallados, que pueden considerarse como representativos de esta variedad de queso, han sido: humedad 34,5 O/o, proteínas 3 1,7 0/o, gras:J 26,7 Ofo, ácido láctico 1,5 0/o y cenizas 6,3 0/o. Sobre la base de la m~tcria seca, el contenido medio en sal es del 4,8 0/o, el de calcio de 1 ,S 0/o y el de fósforo de 1,2 Ofo (relación Ca/1' = 1,27). El valor pll medio es de 5,45 y la aw de 0,90

Printed circuit board coil design with reduced series resistance for high power inductive wireless power transmission systems

Due to the growing use of the popular wireless power transmission (WPT) technology, an innovative method of coil design and optimization is presented in this paper. This method has been applied to develop spiral printed circuit board (PCB) coils with litz-wire structure. From the geometry definition, the design process is carried out by means of finite element analysis (FEA). In addition, as a complement to the design process, some prototypes of spiral PCB coils were built to contrast the simulation results and experimental measurements by means of the small-signal characterization, which reflects the success of the applied method

Estado de degradación proteolítica del queso de Los Pedroches

Las imágenes electroforéticas en gel de poliacrilamida de seis muestras de quesos de los Pedroches maduros, elaborados por diferentes productores, indican que la as-caseína aparece más degradada en todos los quesos que la B-caseína, que apenas es hidrolizada en algunos quesos. La hidrólisis enzimática de la as-caseína (fundamentalmente de la as2- y as3-) origina cuatro productos de escisión de mayor movilidad. La degradación proteolítica de la B-caseína rinde siete fragmentos polipeptídicos de alto peso molecular y baja movilidad electroforética, que se sitúan en la región de la K • y y-caseína. Algunos de estos polipéptidos pueden corresponder a caseínas minoritarias equivalentes a la y-,, TS- y R-caseína eencontradas en qquesos maduros eelaborados con leche de vaca

The Involvement of Urinary Kallikrein in the Renal Escape from the Sodium Retaining Effect of Mineralocorticoids

It is well known that the normal kidney escapes the sodium retaining effect of mineralocorticoids. However, the mechanism that mediates this escape is not understood. The possible role of kallikrein in this escape phenomenon was investigated by placing seven dogs in metabolic cages and giving them a constant sodium diet. After they had been on this diet three days, urine was collected for two 24-hour periods. DOCA (25 mg/day) was then given intramuscularly for five days. Urine was collected daily during this DOCA period and for two additional 24- hour periods. Urine volume, sodium, potassium, protein, and kallikrein excretion were then measured. Urinary kallikrein increased from 251.9 ± 34.8 (mean ± SE) in the second day of the control period to 639.8 ± 110.1 IJ-g/day (P \u3c .01) by the third day of treatment. It remained elevated two days after DOCA was discontinued. Sodium excretion decreased significantly on the first day of DOCA treatment, returning to the previous values thereafter. Urine protein excretion remained constant. The enhanced urinary kallikrein during the escape suggests that the kallikrein system could be involved in the regulation of sodium metabolism by acting as a natriuretic factor, or perhaps by regulating the renal blood flow

Transfer and scattering of wave packets by a nonlinear trap

In the framework of a one-dimensional model with a tightly localized self-attractive nonlinearity, we study the formation and transfer (dragging) of a trapped mode by "nonlinear tweezers", as well as the scattering of coherent linear wave packets on the stationary localized nonlinearity. The use of the nonlinear trap for the dragging allows one to pick up and transfer the relevant structures without grabbing surrounding "garbage". A stability border for the dragged modes is identified by means of of analytical estimates and systematic simulations. In the framework of the scattering problem, the shares of trapped, reflected, and transmitted wave fields are found. Quasi-Airy stationary modes with a divergent norm, that may be dragged by the nonlinear trap moving at a constant acceleration, are briefly considered too.Comment: Phys. Rev. E in pres

Comportamiento de estudiantes de maestro al medir el volumen

Las magnitudes y su medida, por su uso cotidiano, son un contenido de las matemáticas escolares que los estudiantes para maestro de primaria deben dominar. Estos estudiantes presentan lagunas cuando se les proponen tareas para el desarrollo de la competencia de comparación y medida de la capacidad y del volumen. En el presente trabajo se aportan tareas de este tipo y se identifican las estrategias, los errores y dificultades que cometen los estudiantes, al resolverlas. Además, se describe una actuación realizada en el aula para que los estudiantes detecten y superen las estrategias erróneas