922 resultados para STANDARD STARS


Relevância:

20.00% 20.00%

Publicador:

Resumo:

A dynamic atmosphere generator with a naphthalene emission source has been constructed and used for the development and evaluation of a bioluminescence sensor based on the bacteria Pseudomonas fluorescens HK44 immobilized in 2% agar gel (101 cell mL(-1)) placed in sampling tubes. A steady naphthalene emission rate (around 7.3 nmol min(-1) at 27 degrees C and 7.4 mLmin(-1) of purified air) was obtained by covering the diffusion unit containing solid naphthalene with a PTFE filter membrane. The time elapsed from gelation of the agar matrix to analyte exposure (""maturation time"") was found relevant for the bioluminescence assays, being most favorable between 1.5 and 3 h. The maximum light emission, observed after 80 min, is dependent on the analyte concentration and the exposure time (evaluated between 5 and 20 min), but not on the flow rate of naphthalene in the sampling tube, over the range of 1.8-7.4 nmol min(-1). A good linear response was obtained between 50 and 260 nmol L-1 with a limit of detection estimated in 20 nmol L-1 far below the recommended threshold limit value for naphthalene in air. (c) 2008 Elsevier B.V. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Text messaging is a new form of writing, brought about by technological development in the last couple of decades. Mobile phone usage has increased rapidly worldwide and texting is now part of many people's everyday communcation. A large number of users send or receive texts which include some abbreviations and shortenings, commonly referred to as textspeak. This novel linguistic phenomenon is perceived by some with indifference and by others with aggravation. The following study examines attitudes towards this linguistic change from a gender and age perspective. The comparison between two groups show that the most conservative and least positive to change are young women. The analysis and discussion around this focuses on power, prestige and patterns.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The thesis belongs to the field of lexical semantics studies, associated with describing the Russian linguistic world-image. The research focuses on the universal situation of purchase and sale as reflected in the Russian lexical standard and sub-standard. The work deals also with subjects related to the sphere of social linguistics: the social stratification of the language, the structure of sub-standard, etc. The thesis is a contribution to the description of the Russian linguistic world-image as well as to the further elaboration of the conceptional analysis method. The results are applicable in teaching Russian as a foreign language, particularly in lexis and Russian culture and mentality studies.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Recently, two international standard organizations, ISO and OGC, have done the work of standardization for GIS. Current standardization work for providing interoperability among GIS DB focuses on the design of open interfaces. But, this work has not considered procedures and methods for designing river geospatial data. Eventually, river geospatial data has its own model. When we share the data by open interface among heterogeneous GIS DB, differences between models result in the loss of information. In this study a plan was suggested both to respond to these changes in the information envirnment and to provide a future Smart River-based river information service by understanding the current state of river geospatial data model, improving, redesigning the database. Therefore, primary and foreign key, which can distinguish attribute information and entity linkages, were redefined to increase the usability. Database construction of attribute information and entity relationship diagram have been newly redefined to redesign linkages among tables from the perspective of a river standard database. In addition, this study was undertaken to expand the current supplier-oriented operating system to a demand-oriented operating system by establishing an efficient management of river-related information and a utilization system, capable of adapting to the changes of a river management paradigm.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Audio coding is used to compress digital audio signals, thereby reducing the amount of bits needed to transmit or to store an audio signal. This is useful when network bandwidth or storage capacity is very limited. Audio compression algorithms are based on an encoding and decoding process. In the encoding step, the uncompressed audio signal is transformed into a coded representation, thereby compressing the audio signal. Thereafter, the coded audio signal eventually needs to be restored (e.g. for playing back) through decoding of the coded audio signal. The decoder receives the bitstream and reconverts it into an uncompressed signal. ISO-MPEG is a standard for high-quality, low bit-rate video and audio coding. The audio part of the standard is composed by algorithms for high-quality low-bit-rate audio coding, i.e. algorithms that reduce the original bit-rate, while guaranteeing high quality of the audio signal. The audio coding algorithms consists of MPEG-1 (with three different layers), MPEG-2, MPEG-2 AAC, and MPEG-4. This work presents a study of the MPEG-4 AAC audio coding algorithm. Besides, it presents the implementation of the AAC algorithm on different platforms, and comparisons among implementations. The implementations are in C language, in Assembly of Intel Pentium, in C-language using DSP processor, and in HDL. Since each implementation has its own application niche, each one is valid as a final solution. Moreover, another purpose of this work is the comparison among these implementations, considering estimated costs, execution time, and advantages and disadvantages of each one.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper presents a structural monetary úamework featunng a demand function for non-monetary uses of gold, such as the one drawn by Barsky and Summers in their 1988 analy8ÚI of the Gibson Paradox as a natural concomitant of the gold standard period. That structural model predicts that the laws of behavior of nominal prices and interest rates are functions of the rules set by the government to command the money supply. !ta fiduciary vemon obtaina Fisherian relationships &8 particular cases. !ta gold atandard 801ution yields a modelsimilar to the Barsky and Summers model, in which interest rates are exogeneous and subject to shocb. This paper integrates governnment bonds into the analysis, treats interest rates endogenously, and ahifts the responsibility for the shocb to the government budgetary financing policies. The Gibson paradox appears as "practically" the only cl&18 of behavioral pattern open for interest rates and price movements under apure gold standard economy. Fisherian-like relationshipe are utterly ruled out.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

When exploring new perspectives on the impact of non-idealized vs. idealized body image in advertising, studies have focused mainly on body size, i.e., thin vs. heavy (Antioco et al., 2012; Smeesters & Mandel, 2006). Age remains largely unexplored, and the vast majority of ads in the market depict young models. The purpose of this research is therefore to investigate which images in advertisements – young or mature models – are more persuasive for older women (40+ years old). In this investigation, two studies were conducted. The first part was an exploratory analysis with a qualitative approach, which in turn helped to formulate the hypothesis tested in the subsequent experiment. The results of the in-depth interviews suggested a conflict over notions of imprisonment (need to follow beauty standards) and freedom (wish to deviate). The results of the experiment showed essentially that among older consumers, ads portraying older models were as persuasive as ads portraying younger models. Limitations and future research are discussed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The rural electrification is characterized by geographical dispersion of the population, low consumption, high investment by consumers and high cost. Moreover, solar radiation constitutes an inexhaustible source of energy and in its conversion into electricity photovoltaic panels are used. In this study, equations were adjusted to field conditions presented by the manufacturer for current and power of small photovoltaic systems. The mathematical analysis was performed on the photovoltaic rural system I- 100 from ISOFOTON, with power 300 Wp, located at the Experimental Farm Lageado of FCA/UNESP. For the development of such equations, the circuitry of photovoltaic cells has been studied to apply iterative numerical methods for the determination of electrical parameters and possible errors in the appropriate equations in the literature to reality. Therefore, a simulation of a photovoltaic panel was proposed through mathematical equations that were adjusted according to the data of local radiation. The results have presented equations that provide real answers to the user and may assist in the design of these systems, once calculated that the maximum power limit ensures a supply of energy generated. This real sizing helps establishing the possible applications of solar energy to the rural producer and informing the real possibilities of generating electricity from the sun.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Este artigo apresenta valores eletrocardiográficos de 25 bezerros da raça Holandesesa, utilizando-se as derivações bipolares de membro (I, II, III), unipolares aumentadas de membro (avL, avR e avF) e uma derivação bipolar de torax (V10). Dois grupos com animais de diferentes idades foram comparados (18 a 72 horas e 27 a 33 dias de idade). Conclui-se que não houve diferença significativa entre os grupos nas ondas P, Q, R, S e T, nos intervalos PR, QRS, QT e ST e no eixo cardíaco.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The natural gas perform a essential paper, not only in primary sectors of energy, but also in others sectors of economy. The use natural gas will have expansion in Brazil, motivated by governmental decision to increase the participation of this fuel in the Brazilian energy matrix from 4% to 12% up until 2010. in order to reach the objective related to increase the consumption of natural gas in the energy matrix and to propose solutions to attend the electric requirements of heart and refrigeration, using natural gas as primary power plant. This thesis has a main objective to analysis the perception of businessmen of hotel sector about the feasability of investment with micro-cogeneration system by natural gas in their hotel in turistic sector, in Natal/RN. It s show a case for the hotels selected analyzing the actual knowledge of businessmen about alternative of new technology in generation of owner energy. There was make a interview using a standard form researching information about this topic. In this interview has shown 4 (four) canaries for businessmen with different configurations of investment in micro-cogeneration. Two of this canaries uses the project finance like option to make fasible this projects. The resulteis showed who businessmen has insecurity to make decision to put in office alone, or with a local company, and perhaps with a national company to perform for a alternative energy system, justifying, the alone feasability and without information by local businessmen. Apart from that, they are receptive for a option to put in office in micro-cogeneration configured in the settings using project finance

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Galactic stellar clusters have a great variety of physical properties that make valuable probes of stellar and galactic chemical evolution. Current studies show a discrepancy between the standard evolutionary models and observations, mainly considering the level of mixing and convective dilution of light elements, as well as to the evolution of the angular momentum. In order to better settle some of these properties, we present a detailed spectroscopic analysis of 28 evolved stars, from the turn-off to the RGB, belonging to the stellar open cluster M67. The observations were performed using UVES+FLAMES at VLT/UT2. We determined stellar parameters and metallicity from LTE analysis of Fe I and Fe II lines between 420 1100 nm. The Li abundance was obtained using the line at 6707.78 ˚A, for the whole sample of stars. The Li abundances of evolved stars of M67 present a gradual decreasing when decreasing the effective temperature. The Li dilution factor for giant stars of M67 with Teff ∼ 4350K is at least 2300 times greater than that predicted by standard theory for single field giant stars. The Li abundance as a function of rotation exhibits a good correlation for evolved stars of M67, with a much smaller dispersion than the field evolved stars. The mass and the age seem to be some of the parameters that influence this connection. We discovered a Li-rich subgiant star in M67 (S1242). It is member of a spectroscopic binary system with a high eccentricity. Its Li abundance is 2.7, the highest Li content ever measured for an evolved star in M67. Two possibilities could explain this anomalous Li content: (i) preservation of the Li at the post turn off stage due to tidal effects, or (ii) an efficient dredge-up of Li, hidden below the convective zone by atomic diffusion occurring in the post turn off stage. We also study the evolution of the angular momentum for the evolved stars in M67. The results are in agreement with previous studies dedicated to evolved stars of this cluster, where stars in the same region of the CM-diagram have quite similar rotations, but with values that indicate an extra breaking along the main sequence. Finally, we analize the distributions of the average rotational velocity and of the average Li abundance as a function of age. With relation to the average Li abundances, stars in clusters and field stars present the same type of exponencial decay law t−β. Such decay is observed for ages lesser than 2 Gyr. From this age, is observed that the average Li abundance remain constant, differently of the one observed in the rotation age connection, where the average rotational velocity decreases slowly with age

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Orthogonality criterion is used to show in a very simple and general way that anomalous bound-state solutions for the Coulomb potential (hydrino states) do not exist as bona fide solutions of the Schrodinger, Klein-Gordon and Dirac equations. (C) 2007 Elsevier B.V. All rights reserved.