13,445 research outputs found
Derivation of an Abelian effective model for instanton chains in 3D Yang-Mills theory
In this work, we derive a recently proposed Abelian model to describe the
interaction of correlated monopoles, center vortices, and dual fields in three
dimensional SU(2) Yang-Mills theory. Following recent polymer techniques,
special care is taken to obtain the end-to-end probability for a single
interacting center vortex, which constitutes a key ingredient to represent the
ensemble integration.Comment: 18 pages, LaTe
Influência do uso nas características físico químicas de um latossolo amarelo, textura muito argilosa, Manaus, AM.
O objetivo deste estudo foi: verificar alterações em algumas propriedades físico-químicas do solos provocadas pelo uso; a que profundidade ocorre e verificar o efeito da cobertura do solo com kudzu. As áreas em que foram feitas as amostragens se localizam no Campo Experimental da EMBRAPA-CPAA, Km 29 da AM-010, no município de Manaus, AM
Características de adsorção de fósforo em solos da Bacia Petrolífera de Urucu.
Este trabalho teve como objetivos quantificar a adsorção de fósforo em solos originários de quatro locais da BOGPM, bacia petrolífera de Urucu, em Coari-AM, bem como avaliar a influência de alguns atributos do solo sobre esta característica
An explanation for the interaction mechanism of an anionic polymeric additive on yeast flocculent cells
Magna Floc LT25 is a high molecular weight anionic polymer that has been described as increasing reaction rates inside flocs of yeast cells. However, no clear indication has been given on how this anionic polymer interacts with flocculent cells. Flocculation experiments made with a strain ofSaccharomyces cerevisiae corroborate that it bridges calcium ions bound to flocculent yeast cell walls, thus enlarging the available flux area for the transport of solutes inside the flocs
Análise de Componentes Principais em Caracteres Morfológicos de Coffea arabica L.
Este trabalho teve como objetivo estudar quais caracteres morfológicos de maior importância na discriminação de genótipos de Coffea arabica L. Foram avaliados 250 acessos de C. arabica (cultivares, híbridos e alguns genótipos selvagens) oriundos do banco de germoplasma de café, instalado na fazenda experimental da Empresa de Pesquisa Agropecuária de Minas Gerais, em Patrocínio, MG. O delineamento utilizado foi de blocos casualizados com duas repetições, espaçamento de 3,5 x 0,8 metros, com parcelas de dez plantas. Os caracteres morfológicos foram avaliados em 2006, 12 meses após a implantação da cultura, com as plantas ainda na fase juvenil. Por meio dos resultados é possível observar que o ?comprimento do 1º ramo plagiotrópico?, ?vigor?, ?diâmetro do caule? e ?número de nós do 1º ramo plagiotrópico? são as variáveis de maior importância na distinção dos materiais. Assim, podem-se concentrar maiores esforços na avaliação das mesmas, descartando a avaliação das outras variáveis
Causal Anomalies in Kaluza-Klein Gravity Theories
Causal anomalies in two Kaluza-Klein gravity theories are examined,
particularly as to whether these theories permit solutions in which the
causality principle is violated. It is found that similarly to general
relativity the field equations of the space-time-mass Kaluza-Klein (STM-KK)
gravity theory do not exclude violation of causality of G\"odel type, whereas
the induced matter Kaluza-Klein (IM-KK) gravity rules out noncausal
G\"odel-type models. The induced matter version of general relativity is shown
to be an efficient therapy for causal anomalies that occurs in a wide class of
noncausal geometries. Perfect fluid and dust G\"odel-type solutions of the
STM-KK field equations are studied. It is shown that every G\"odel-type perfect
fluid solution is isometric to the unique dust solution of the STM-KK field
equations. The question as to whether 5-D G\"odel-type non-causal geometries
induce any physically acceptable 4-D energy-momentum tensor is also addressed.Comment: 16 page. LaTex file. To appear in Int. J. Mod. Phys. A (1998
Phase separation methodology for physicochemical studies of soils.
A detailed study of a soil in every country is of a paramount importance, because it determines an entire economic strategy. The mineralogical properties of soils have been studied in the world for more than 100 years by various characterization techniques, X-ray diffraction being the most prominent. The main difficulty in most of employed techniques is the dominance of the majority phases in the response or the measured signal from the sample that becloud minority phases preventing their identification. The application of methods of phases'separation would provide the possibility to discern minority phases in soils. This work presents a phase separation method that employs a combination of two phenomena based on principles of fluid dynamics: flotation and sedimentation. Different characterization methods were used to analyse the produced soil samples. The methodology employed for separation of phases allowed the complete separation of clay phase from heavier mineral phases. This result makes it possible to discern minority mineral phases of soils that are difficult to detect. A more accurate determination of the mineralogical composition of a soil becomes feasible
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