992 resultados para 198-1209
Resumo:
An immunochemical study of ovine follicle-stimulating hormone and its antibody carried out by using precipitin, agglutinating and complement-fixation systems, has suggested that the follicle-stimulating hormone, possibly by virtue of it being a univalent antigen, forms a soluble complex with its specific antibody. This antiserum is species nonspecific in that it is able to neutralize the follicle-stimulating activity of rat, mouse, hamster, guinea pig pituitary extracts, and pregnant mare serum gonadotropin. Human chorionic gonadotropin, however, has been shown not to form a complex with the follicle-stimulating hormone specific antibody.
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We consider the secondary flows arising in the motion of a Maxwell fluid between two rotating coaxial cones having the same vertex. We find that in any meridian plane passing through the common axis of the cones, the flow field is divided into two regions. Such a division of flow field was first reported by Bhatnagar and Rathna.
Resumo:
Different seismic hazard components pertaining to Bangalore city,namely soil overburden thickness, effective shear-wave velocity, factor of safety against liquefaction potential, peak ground acceleration at the seismic bedrock, site response in terms of amplification factor, and the predominant frequency, has been individually evaluated. The overburden thickness distribution, predominantly in the range of 5-10 m in the city, has been estimated through a sub-surface model from geotechnical bore-log data. The effective shear-wave velocity distribution, established through Multi-channel Analysis of Surface Wave (MASW) survey and subsequent data interpretation through dispersion analysis, exhibits site class D (180-360 m/s), site class C (360-760 m/s), and site class B (760-1500 m/s) in compliance to the National Earthquake Hazard Reduction Program (NEHRP) nomenclature. The peak ground acceleration has been estimated through deterministic approach, based on the maximum credible earthquake of M-W = 5.1 assumed to be nucleating from the closest active seismic source (Mandya-Channapatna-Bangalore Lineament). The 1-D site response factor, computed at each borehole through geotechnical analysis across the study region, is seen to be ranging from around amplification of one to as high as four times. Correspondingly, the predominant frequency estimated from the Fourier spectrum is found to be predominantly in range of 3.5-5.0 Hz. The soil liquefaction hazard assessment has been estimated in terms of factor of safety against liquefaction potential using standard penetration test data and the underlying soil properties that indicates 90% of the study region to be non-liquefiable. The spatial distributions of the different hazard entities are placed on a GIS platform and subsequently, integrated through analytical hierarchal process. The accomplished deterministic hazard map shows high hazard coverage in the western areas. The microzonation, thus, achieved is envisaged as a first-cut assessment of the site specific hazard in laying out a framework for higher order seismic microzonation as well as a useful decision support tool in overall land-use planning, and hazard management. (C) 2010 Elsevier Ltd. All rights reserved.
Resumo:
Perhaps the most fundamental prediction of financial theory is that the expected returns on financial assets are determined by the amount of risk contained in their payoffs. Assets with a riskier payoff pattern should provide higher expected returns than assets that are otherwise similar but provide payoffs that contain less risk. Financial theory also predicts that not all types of risks should be compensated with higher expected returns. It is well-known that the asset-specific risk can be diversified away, whereas the systematic component of risk that affects all assets remains even in large portfolios. Thus, the asset-specific risk that the investor can easily get rid of by diversification should not lead to higher expected returns, and only the shared movement of individual asset returns – the sensitivity of these assets to a set of systematic risk factors – should matter for asset pricing. It is within this framework that this thesis is situated. The first essay proposes a new systematic risk factor, hypothesized to be correlated with changes in investor risk aversion, which manages to explain a large fraction of the return variation in the cross-section of stock returns. The second and third essays investigate the pricing of asset-specific risk, uncorrelated with commonly used risk factors, in the cross-section of stock returns. The three essays mentioned above use stock market data from the U.S. The fourth essay presents a new total return stock market index for the Finnish stock market beginning from the opening of the Helsinki Stock Exchange in 1912 and ending in 1969 when other total return indices become available. Because a total return stock market index for the period prior to 1970 has not been available before, academics and stock market participants have not known the historical return that stock market investors in Finland could have achieved on their investments. The new stock market index presented in essay 4 makes it possible, for the first time, to calculate the historical average return on the Finnish stock market and to conduct further studies that require long time-series of data.
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Simple ARC designs for germanium (Ge) optics useful in spaceborne electro-optical systems have been generated. It is seen that the designs which are non-quarterwave in nature are efficient in terms of spectral coverage and residual reflection loss. They have been realised experimentally and the resulting ARCs are found to have very good spectral and durability properties.
Resumo:
Jatkosodan aikana kerättiin Suomen valtaamalta alueelta Itä-Karjalasta tuhansittain museoesineitä Suomen museoihin. Kansallismuseon kokoelmiin kerättiin esineitä lähinnä suomenheimoisilta mutta myös isovenäläisiltä. Tämän tutkimuksen kohteena on lähes 400:n esineen kokoelma, joka toimitettiin Kansallismuseoon vuosina 1941 1944 ja merkittiin kansallisuudeltaan venäläiseksi. Näistä venäläisistä esineistä suurimman osan keräsi alikersanttina palvellut Väinö Tuomaala. Tutkimukseni tarkastelee Väinö Tuomaalan kokoelmaa ja etsii syitä siihen, miksi kokoelma on sellainen kuin se on, miksi se ja koko venäläisten esineiden kokoelma syntyi ja mitkä seikat vaikuttivat Tuomaalan esinevalintoihin. Tutkimuksen teoria rakentuu museologisen kirjallisuuden varaan. Tutkimuksessa tarkastellaan Väinö Tuomaalan kokoelman keräyskonteksteja. Keräyskonteksteihin kuuluvat kokoelman kerääjä, keräysajankohta ja -paikka sekä yhteenkuuluvat esineet, eli muut venäläiset esineet. Kerääjän tarkastelussa huomioidaan hänen henkilöhistoriansa ja etsitään mahdollisia keruuseen vaikuttaneita tekijöitä. Keräysajankohdan tarkastelussa huomio kiinnittyy keruuympäristöön, eli vallitseviin olosuhteisiin ja aatteelliseen ilmapiiriin, joiden vaikutuksen alaisena keruu suoritettiin. Primääriaineisto koostuu Kansallismuseon alaisen Kulttuurien museon yleisetnografisten esineiden kokoelmaan kuuluvista 198:sta Väinö Tuomaalan keräämästä esineestä verifikaatteineen, jotka ovat osa 393 esinettä käsittävästä venäläisestä kokoelmasta. Aineisto sisältää myös eri arkistojen materiaalia. Kansallisarkiston Sörnäisten toimipisteestä, entisestä sota-arkistota, löytyneitä sotapäiväkirjoja ja Tuomaalan kantakorttia on tutkimuksessa käytetty jatkosodan tapahtumien esittämiseen. Museoviraston hallinto-osaston arkiston kirjeet ja pöytäkirjat ovat antaneet tietoa kulttuurikeruun organisoinnista. Väinö Tuomaalan arkistokokoelma Seinäjoella sisältää Tuomaalan keräämää perinneaineistoa, hänen puheitaan, lehtikirjoituksiaan ja kirjeenvaihtoaan. Myös Evijärven kunnantalon kotiseutuarkistosta löytyneet kirjeet ovat valottaneet Tuomaalan jatkosodan aikaista keruutoimintaa. Suomalaisen Kirjallisuuden Seuran arkistot ovat tarjonneet materiaalia jatkosodan aikaisesta kulttuurikeruusta. Koko venäläisten esineiden kokoelma syntyi sattumalta ja organisoimattoman toiminnan tuloksena, jossa aktiivisia toimijoita olivat yksittäiset kerääjät. Intohimoisesta suhtautumisesta kansatieteellistä keruuta kohtaan johtuen, Tuomaala olisi todenäköisesti kerännyt museoesineitä missä päin Itä-Karjalaa tahansa. Väinö Tuomaalan Itä-Karjalassa keräämä esinekokoelma oli luonnollinen jatke hänen kotiseudullaan aloittamalleen keräystoiminnalle. Tuomaalan jatkosodan aikana keräämä kokoelma on kerääjän mieltymysten mukainen yritys kerätä vanhaa itäkarjalaista, kansallista talonpoikaiskulttuuria. Tuomaala pyrki keräämään klassista kansatieteellistä aineistoa monipuolisesti kansankulttuurin eri elämänalueilta. Tuomaalan esinekeruussa näkyi vahvasti talonpoikaiskulttuurin ihannointi ja halu pelastaa osa siitä tuleville sukupolville. Yrityksen onnistumiseen vaikuttivat sodanajan olosuhteet sekä aatteellinen ilmapiiri. Esineiden saatavuudella oli merkittävä osa kokoelman muodostumiseen, samoin Tuomaalan käsityksillä heimokansoista, Suur-Suomesta ja venäläisistä. Keruuvalintoihin ja keruun jatkumiseen vaikuttivat myös Kansallismuseon henkilökunta ja työstä saatu tunnustus.
Resumo:
This paper elucidates the relative importance of soil structure and various compositional factors in influencing the liquid limit of natural kaolinitic soils. Earlier studies dealt with purified systems and anticipated that the liquid limit of the soils would increase with percentage clay size fraction and surface area, and that soils with a greater degree of paricle flocculation would possess a higher liquid limit than soils with a more parallel particle arrangement. The results revealed that the inter-particle attraction and repulsion forces have a prominent role in determining the liquid limit of kaolinitic soils. These forces determine the particle arrangement (clay fabric) which in turn regulates the liquid limit values. The influence of clay fabric was ascertained from the relationships of liquid limit with shrinkage limit and sediment volume (in water) values. It was anticipated that kaolinitic soils with a greater degree of particle flocculatin and a higher liquid limit would shrink less and occupy a higher sedimentation volume. As expected an increase in liquid limit was accompanied by an increase in shrinkage limit and sediment volume in water.
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A structure consisting of the polyproline-II or collagen-like helix immediately succeeded by a ?-turn is seen in several synthetic peptides and has been suggested to be the conformational requirement for proline hydroxylation in nascent procollagen. Using a simple algorithm for detecting secondary structures, we have analysed crystal structure data on 40 globular proteins and have found eight examples of the collagen-helix + ?-turn supersecondary structure in 15 proteins that contain the collagen-like helical segments.
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Cytochrome P-450 has been purified from phenobarbital-treated rat livers to a specific content of 17 nmol/mg protein. The major species purified has a molecular weight of 48,000. Using the purified antibody for the cytochrome P-450 preparation it has been shown that the major product synthesized in vivo and in the homologous cell-free system in vitro is the 48,000 molecular weight species. Poly(A)-containing RNA isolated from phenobarbital-treated animals codes for the synthesis of the 48,000 molecular weight species in the wheat germ and reticulocyte lysate cell-free systems. It is concluded that cytochrome P-450 synthesis does not involve processing of a polyprotein precursor, although certain minor modifications including glycosylation of the primary translation product are not ruled out. Phenobarbital treatment of the animal results in a significant increase in the cytochrome P-450 messenger activity as measured in the wheat germ cell-free system.
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Nucleotide pyrophosphatase of mung bean seedlings has earlier been isolated in our laboratory in a dimeric form (Mr 65,000) and has been shown to be converted to a tetramer by AMP and to a monomer by p-hydroxymercuribenzoate. All the molecular forms were enzymatically active with different kinetic properties. By a modified procedure using blue-Sepharose affinity chromatography, we have now obtained a dimeric form of the enzyme which is desensitized to AMP interaction. The molecular weight of the desensitized form of the enzyme was found to be the same as that of the native dimeric enzyme. However, the desensitized enzyme functioned with a linear time course, contrary to the biphasic time course exhibited by the native enzyme. In addition, it was not converted to a tetramer on the addition of AMP, had only one binding site for adenine nucleotides, and p-hydroxy-mercuribenzoate had no effect on the time course of the reaction or on the molecular weight of the enzyme. The temperature optimum of the desensitized enzyme was found to be 67 °C in contrast to the optimum of 49 °C for the native dimer. Fifty percent of the tryptophan residues of the desensitized enzyme were not accessible for quenching by iodide. Fluorescence studies gave Kd values of 0.34, 2.2, and 0.8 mImage for AMP, ADP, and ATP, which were close to the Ki values of 0.12, 2.2, and 0.9 mImage , respectively, for these nucleotides. The binding and inhibition studies with AMP and its analogs showed that the 6-amino group and the 5′-phosphate group were essential for the inhibition of the enzyme activity.
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Theoretical calculations of the geminal carbonyl-13C- proton coupling constant, 2J(C′H), in α-amino acids have been carried out using Dirac Vector model and Penney-Dirac bond order formulations. The results indicate that the couplings are dependent on the backbone torsion angle psi (ψ) of the amino acid residues in peptides. The meagre available experimental data seem to support the theoretical findings.
Resumo:
Process control systems are designed for a closed-loop peak magnitude of 2dB, which corresponds to a damping coefficient () of 0.5 approximately. With this specified constraint, the designer should choose and/or design the loop components to maintain a constant relative stability. However, the manipulative variable in almost all chemical processes will be the flow rate of a process stream. Since the gains and the time constants of the process will be functions of the manipulative variable, a constant relative stability cannot be maintained. Up to now, this problem has been overcome either by selecting proper control valve flow characteristics or by gain scheduling of controller parameters. Nevertheless, if a wrong control valve selection is made then one has to account for huge loss in controllability or eventually it may lead to an unstable control system. To overcome these problems, a compensator device that can bring back the relative stability of the control system was proposed. This compensator is similar to a dynamic nonlinear controller that has both online and offline information on several factors related to the control system. The design and analysis of the proposed compensator is discussed in this article. Finally, the performance of the compensator is validated by applying it to a two-tank blending process. It has been observed that by using a compensator in the process control system, the relative stability could be brought back to a great extent despite the effects of changes in manipulative flow rate.