898 research outputs found
Stimulus specificity in the acquisition and extinction of conditioned taste aversion
Vogel, E.H. Universidad de Talca, Escuela de Psicología, Casilla N° 747, Talca, Chile.An experiment evaluated whether the acquisition and extinction of conditioned taste aversion in the rat is stimulus-specific by testing the degree of response transfer between sweet and salty tastes. Animals in the paired-same and paired-different groups received a presentation of a gustatory CS and a cyclophosphamide injection US. Nonconditioned control groups received unpaired CS /US presentations or the CS followed by a vehicle injection. Taste avoidance was evaluated in three nonreinforced test sessions. In the paired-same, unpaired and vehicle groups, all test sessions were conducted with the same flavor as originally used in training, whereas the paired-different group was tested with a novel flavor on the first and second sessions and with the originally trained flavor in last session. Stimulus specific acquisition was apparent in the first test session, when the animals in the group paired-same exhibited lower fluid intake than the other three groups. Evidence of specificity of extinction was apparent in the last test session, when animals in the group paired-different exhibited lower fluid intake than the other three groups. These results provide further evidence of stimulus specificity in acquisition and extinction of conditioned taste aversion, supporting the associative interpretation of these phenomen
An artificial immune system for fuzzy-rule induction in data mining
This work proposes a classification-rule discovery algorithm integrating artificial immune systems and fuzzy systems. The algorithm consists of two parts: a sequential covering procedure and a rule evolution procedure. Each antibody (candidate solution) corresponds to a classification rule. The classification of new examples (antigens) considers not only the fitness of a fuzzy rule based on the entire training set, but also the affinity between the rule and the new example. This affinity must be greater than a threshold in order for the fuzzy rule to be activated, and it is proposed an adaptive procedure for computing this threshold for each rule. This paper reports results for the proposed algorithm in several data sets. Results are analyzed with respect to both predictive accuracy and rule set simplicity, and are compared with C4.5rules, a very popular data mining algorithm
Photoelasticity as a Research Technique for Analyzing Stresses in Dental Structures
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67063/2/10.1177_00220345550340060601.pd
An effective Lagrangian approach for unstable particles
We propose a novel procedure for handling processes that involve unstable
intermediate particles. By using gauge-invariant effective Lagrangians it is
possible to perform a gauge-invariant resummation of (arbitrary) self-energy
effects. For instance, gauge-invariant tree-level amplitudes can be constructed
with the decay widths of the unstable particles properly included in the
propagators. In these tree-level amplitudes modified vertices are used, which
contain extra gauge-restoring terms prescribed by the effective Lagrangians. We
discuss the treatment of the phenomenologically important unstable particles,
like the top-quark, the - and -bosons, and the Higgs-boson, and derive
the relevant modified Feynman rules explicitly.Comment: 32 pages, LaTeX2e (uses axodraw.sty); Eq. (B.6) corrected, references
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Efecto sobre la calidad de la leche, características tecnológicas y producción quesera de la raza merina de grazalema frente al cruce con razas mejoradas
En los últimos años se están incorporando masivamente en España, en
general y Andalucía en particular, razas ovinas foráneas de aptitud lechera,
fundamentalmente las razas Assaf, Awassi y Lacaune. Su introducción está
fomentando asimismo, la realización de cruces indiscriminados con nuestras
razas ovinas autóctonas, de aptitud lechera pero de menor especialización,
al menos cuantitativamente (Casas et al., 2005).
El objetivo de este estudio ha sido analizar en dos grupos de animales de
un mismo rebaño (ovejas puras de raza Merina de Grazalema, y ovejas cruzadas Merina de Grazalema x Awassi) las características de la producción lechera, y proceder a la elaboración de quesos para estudiar las posibles Consejería de Agricultura y Pesca 34 diferencias tecnológicas de los quesos derivados de ambas elaboraciones. A través del mismo se ha comprobado una mayor producción lechera de las ovejas cruzadas (167,35±13,20 kg frente a 136,84±4,25 kg) pero con un porcentaje de grasa (6,25±0,34 % frente a 8,27±0,22 %), proteína (4,71±0,14 % frente a 5,80±0,09 %) y extracto seco (10,97±0,46 % frente a 14,07±0,28 %) estadísticamente inferior.
En cuanto a los parámetros de aptitud tecnológica, los valores de tiempo
de coagulación medio (24,70±0,77 minutos), dureza media (dureza del coágulo a los 30 minutos) de 25,03±2,27 mm, y el rendimiento en cuajada
(327,50±5,70 g/l), mostraron cifras inferiores a las referenciadas por Casas
et al. (2005) para la raza ovina Merina de Grazalema. Finalmente, la velocidad de endurecimiento resultó mayor a los valores obtenidos en el trabajo citado anteriormente (4,59±0,54 min). Por otro lado, estos mismos parámetros mostraron valores inferiores en el tiempo de coagulación
(19,60±0,62 minutos), velocidad de endurecimiento (3,97±0,38 min) y rendimiento en cuajada (290,55±6,67), mientras que la dureza media
(32,85±2,03 mm) fue superior en las ovejas cruzadas, respecto a los valores
encontrados en esta misma explotación para los animales puros.
Como consecuencia de todo ello, el rendimiento quesero real fue del
30,25 % para las ovejas puras frente al 23,70 % de las cruzadas.
Esto determina que la producción quesera real que se obtiene por oveja
pura, sea superior al de la cruzada (41,38 kg queso fresco/ lactación frente
a los 39,70 de la cruzada).Proyecto INIA. Ministerio de Educación y Ciencia
Comparison between the thermal properties of cement composites using infrared thermal images
The use of agribusiness residual lignocellulosic fibres can be a good alternative in the
development of lignocellulosic composites. The current work aimed to investigate the thermal
performance of cement-based composites with lignocellulosic materials: Eucalyptus, sugarcane
bagasse, coconut fibre in comparison with commercial gypsum board to be used as internal
partitions of the building using infrared thermal images. Three repetitions for each kind of
lignocellulosic material were made, and three commercial gypsum boards were used. In the
production of the panels, the following parameters were applied: material and cement ratio,
1:2.75; water and cement ratio, 1:2.5; hydration water rate of 0.25; additive, 4% (based on cement
mass). The calculations were performed for a nominal panel density of 1,200 kg m-
³. The thermal
analysis was performed in a chamber composed of MDP (Medium-Density Particleboard) and
with an internal layer of rock wool and the heat source (thermal resistance). For the superficial
temperature measurement, a FLIR E75 camera was used to capture the infrared images. When
the internal temperature of the chamber stabilized at 50 °C, an infrared thermal image was
collected from each side of the composite. Thermal properties were analysed: thermal
conductivity, resistivity, resistance, and transmittance. Based on the results, sugar cane cement
composites were characterized by higher values of thermal conductivity. Related to thermal
resistivity, thermal resistance, and thermal transmittance, only the coconut panel presented
similar behaviour to the commercial gypsum board. Thus, cement composite using coconut can
be a potential alternative that might solve energy and environmental concerns simultaneously
Methionine adenosyltransferase S-nitrosylation is regulated by the basic and acidic amino acids surrounding the target thiol
S-Adenosylmethionine serves as the methyl donor for many biological methylation reactions and provides the propylamine group for the synthesis of polyamines. S-Adenosylmethionine is synthesized from methionine and ATP by the enzyme methionine adenosyltransferase. The cellular factors regulating S-adenosylmethionine synthesis have not been well defined. Here we show that in rat hepatocytes S-nitrosoglutathione monoethyl ester, a cell-permeable nitric oxide donor, markedly reduces cellular S-adenosylmethionine content via inactivation of methionine adenosyltransferase by S-nitrosylation. Removal of the nitric oxide donor from the incubation medium leads to the denitrosylation and reactivation of methionine adenosyltransferase and to the rapid recovery of cellular S-adenosylmethionine levels. Nitric oxide inactivates methionine adenosyltransferase via S-nitrosylation of cysteine 121. Replacement of the acidic (aspartate 355) or basic (arginine 357 and arginine 363) amino acids located in the vicinity of cysteine 121 by serine leads to a marked reduction in the ability of nitric oxide to S-nitrosylate and inactivate hepatic methionine adenosyltransferase. These results indicate that protein S-nitrosylation is regulated by the basic and acidic amino acids surrounding the target cysteine
Physicochemical Compatibility of Agrochemical Mixtures in Spray Tanks for Paddy Field Rice Crops
Schroedingers equation with gauge coupling derived from a continuity equation
We consider a statistical ensemble of particles of mass m, which can be
described by a probability density \rho and a probability current \vec{j} of
the form \rho \nabla S/m. The continuity equation for \rho and \vec{j} implies
a first differential equation for the basic variables \rho and S. We further
assume that this system may be described by a linear differential equation for
a complex state variable \chi. Using this assumptions and the simplest possible
Ansatz \chi(\rho,S) Schroedingers equation for a particle of mass m in an
external potential V(q,t) is deduced. All calculations are performed for a
single spatial dimension (variable q) Using a second Ansatz \chi(\rho,S,q,t)
which allows for an explict q,t-dependence of \chi, one obtains a generalized
Schroedinger equation with an unusual external influence described by a
time-dependent Planck constant. All other modifications of Schroeodingers
equation obtained within this Ansatz may be eliminated by means of a gauge
transformation. Thus, this second Ansatz may be considered as a generalized
gauging procedure. Finally, making a third Ansatz, which allows for an
non-unique external q,t-dependence of \chi, one obtains Schroedingers equation
with electromagnetic potentials \vec{A}, \phi in the familiar gauge coupling
form. A possible source of the non-uniqueness is pointed out.Comment: 25 pages, no figure
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