Exterior view of Gottschalk residence; Seelhorst Strasse 27, Hannover, Germany.

Fig. 13 in family portrait

Gottschalk residence; Seelhorst Strasse 27, Hannover, Germany.

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Theoretical study of a 16-µm CO2 downstream-mixing gasdynamic laser: A two-dimensional approach

A 16-µm CO2-N2 downstream-mixing gasdynamic laser, where a cold CO2 stream is mixed with a vibrationally excited N2 stream at the exit of the nozzle, is studied theoretically. The flow field is analyzed using a two-dimensional, unsteady, laminar and viscous flow model including appropriate finite-rate vibrational kinetic equations. The analysis showed that local small-signal gain up to 21.75 m−1 can be obtained for a N2 reservoir temperature of 2000 K and a velocity ratio of 1:1 between the CO2 and N2 mixing streams. Applied Physics Letters is copyrighted by The American Institute of Physics.

Silva Fennica Vol. 27, 1993.

Julkaistu Silva Fennica Vol. 27(4) -numeron liitteenä.

Homeostatic regulation of free retinol-binding protein and free thyroxine pools of plasma by their plasma carrier proteins in chicken

The mechanism underlying homeostatic regulation of the plasma levels of free retinol-binding protein and free thyroxine, the systemic distribution of which is of great importance, has been investigated. A simple method has been developed to determine the rate of dissociation of a ligand from the binding protein. Analysis of the dissociation process of retinol-binding protein from prealbumin-2 reveals that the free retinol-binding protein pool undergoes massive flux, and the prealbumin-2 participates in homeostatic regulation of the free retinol-binding protein pool. Studies on the dissociation process of thyroxine from its plasma carrier proteins show that the various plasma carrier proteins share two roles. Of the two types of protein, the thyroxine-binding globulin (the high affinity binding protein) contributes only 27% of the free thyroxine in a rapid transition process, despite its being the major binding protein. But prealbumin-2, which has lower affinity towards thyroxine, participates mainly in a rapid flux of the free thyroxine pool. Thus thyroxine-binding globulin acts predominantly as a plasma reservoir of thyroxine, and also probably in the �buffering� action on plasma free thyroxine level, in the long term, while prealbumin-2 participates mainly in the maintainance of constancy of free thyroxine levels even in the short term. The existence of these two types of binding protein facilitates compensation for the metabolic flux of the free ligand and maintenance of the thyroxine pool within a very narrow range.

An Investigation Of Alkali Aluminosilicate Glasses By Si-29 And Al-27 Magic-Angle-Spinning Nmr-Spectroscopy

Alkali aluminosilicate glasses prepared by the gel and the melt routes have been investigated by Si-29 and Al-27 MAS NMR spectroscopy. It is found that Al has a tetrahedral coordination in the gel glasses modified with equivalent proportions of alkalis unlike in a pure aluminosilicate glass where Al has both four and six coordinations. Silicon is present as Q4 units in all the 5M2O 5Al2O3 9OSiO2 ( M = Li, Na and K) gel glasses studied whereas it is present in Q2 or Q3 species in the lithium aluminosilicate glasses of compositions 40Li2O x Al2O3 (1-x)SiO2 (1 less-than-or-equal-to x less-than-or-equal-to 15) and xLi2O 10Al2O3 (1-x)SiO2 (20 less-than-or-equal-to x less-than-or-equal-to 40). The combination of Q2 and Q3 is also found in certain sodium aluminosilicate glasses, but they change to Q2 and Q1 as the concentration of SiO2 decreases.

Structure and properties of fibre reinforced zn-27% al alloy based cast MMCs

Metal matrix composites (MMCs) based on a zinc-27% aluminium alloy (ZA-27) were produced using a pressure infiltration technique. Preforms of alumina fibres and aluminosilicate fibres were used for reinforcement. Uniform distribution of fibres and satisfactory interfacial bonding were achieved. UTS, specific strength, hardness and wear resistance were improved significantly by the alumina fibre reinforcement, but UTS decreased when using aluminosilicate fibres for reinforcement mainly due to unavoidable clustering of particles in the fibre preforms. Structure-property relations have been analysed in all cases.

Synthesis based on cyclohexadienes. Part-27. Synthesis of functionalized tricyclo[5.2.2.0(1,5)]undecanes

A new methodology for the construction of tricyclo[5.2.2.0(1,5)]undecanes is described from indane-4-carboxylic acids. Birch reduction of indane-4-carboxylic acids followed by conjugation and cycloaddition with alpha-chloroacrylonitrile and hydrolysis lead to the tricyclic compounds 36 and 48 which are intermediates in the eremolactone synthesis.

The 27-plet contributions to the CP-conserving K -> pi l(+)l(-) decays

We revisit the rare kaon decays K -> pi l(+)l(-) which are of special interest due to the recent measurements of the charged kaon decay spectra. We compute the contribution of the 27-plet to the decay amplitudes in one loop SU(3) chiral perturbation theory. We estimate the resulting impact to be similar to 10% to the branching ratios of the charged kaon decays, and also noticeably influence the shape of the spectra. With current values of the constants G(8) associated with the octet and G(27) associated with the 27-plet, the contribution of the latter pushes the spectrum in the correct direction, towards the charged lepton spectra. We also discuss the impact for neutral decay rates and spectra.

Caracterización de la Finca "San Benito" en Telica, León, Nicaragua

El presente trabajo se realizó dentro del marco del proyecto RAREN CEG NICARAGUA - ONG 157/86/IT, 'con el objetivo de realizar una Caracterización de la finca "San Benito" y su entorno Télica, León. Este consistió en un diagnóstico estático en la zona y un diagnóstico dinámico en la finca. Se determinó que la zona de vida correspondiente a Télica es trópico seco con precipitación anual de (1378.50 mm), temperaturas de (27.7°C) promedios. Los suelos poseen alto contenido de materia orgánica y nutriente, excepto el Fósforo. Se caracteriza por el predominio del sistema de producción de doble propósito, carácter extensivo, en el que se explota, ganado cebuino cruzado con Pardo Suizo principalmente. La inversión de capital y de recursos es baja. La alimentación del ganado se basa en el pastoreo, habiendo predominio del pasto Jaragua < Hyparrenia ruffa). Siendo el resto pasto natural. Entre los principales factores limitantes identificados se puede mencionar mal manejo de los potreros esto disminuye la calidad y disponibilidad del forraje ofrecido a los animales, unido a una falta de técnicas da conservación y suplementación adecuada. Solo el 30% comercializa su producto a la población cercana. Entre los índices técnicos encontrados en la zona se determinó que la natalidad es 45%, la mortalidad de terneros 10%), mortalidad adulto (3%), duración de lactancia (180) días, la producción vaca día (2.5) litros, destete efectivo (40%). Respecto al sistema de producción de la finca “San Benito” este se caracteriza por ser de doble propósito con mayor énfasis en la producción de leche. El hato presenta un alto grado de encaste de Pardo Suizo (75%) y Brahaman (25%). Las media de producción de PL305, PLTOT, LARLA e IPP encontrados fueron de 1356.25 Kg leche, 1279.20 Kg leche 290.68 días y 468.00 días respectivamente la PLD resultó de 4 litros. Correlaciones lineales entre la producción leche día (KLD) y el porcentaje da materia seca (%MS) resulto de (-0.544) y en relación a la disponibilidad de materia seca total es (-0.263) y con respecto a la disponibilidad de materia seca por vaca es de (0.488). Entre los principales factores limitantes encontrados en la finca ''San Benito'1 se determinó que en la época seca el ganado sufre un déficit considerable en la alimentación lo que puede obedecer a la escasez de agua, falta de fertilización de los potreros, además de no existir una fuente proteica como complemento, falta de Técnicas de conservación de pastos y forrajes para enfrentar la falta de alimento en esa época. La rentabilidad de la finca es de 9.88% la cual es relativamente alta.