1,521 research outputs found
Comment on "Critique of q-entropy for thermal statistics" by M. Nauenberg
It was recently published by M. Nauenberg [1] a quite long list of objections
about the physical validity for thermal statistics of the theory sometimes
referred to in the literature as {\it nonextensive statistical mechanics}. This
generalization of Boltzmann-Gibbs (BG) statistical mechanics is based on the
following expression for the entropy:
S_q= k\frac{1- \sum_{i=1}^Wp_i^q}{q-1} (q \in {\cal R}; S_1=S_{BG} \equiv
-k\sum_{i=1}^W p_i \ln p_i) .
The author of [1] already presented orally the essence of his arguments in
1993 during a scientific meeting in Buenos Aires. I am replying now
simultaneously to the just cited paper, as well as to the 1993 objections
(essentially, the violation of "fundamental thermodynamic concepts", as stated
in the Abstract of [1]).Comment: 7 pages including 2 figures. This is a reply to M. Nauenberg, Phys.
Rev. E 67, 036114 (2003
Rock Powder Can Improve Vermicompost Chemical Properties and Plant Nutrition: an On-farm Experiment
Together with farmers, we evaluated nutrient availability from vermicomposted gneiss powder, assessed its influence on growth promotion, nutrition and heavy metal accumulation in maize plants and the effect on soil chemical properties in the field. Three soil treatments were applied: fertilization with vermicompost with gneiss powder, fertilization with vermicompost without gneiss powder, and soil without fertilization (control), in a randomized block design with five replicates. The dry weight of shoots and the concentrations of potassium, calcium, magnesium, manganese, nickel, chrome and lead in the dry matter of maize were higher with vermicompost with gneiss powder. In the soil, the potential of hydrogen and phosphorus, potassium and calcium concentrations were higher with vermicompost with gneiss. There were no detectable levels of heavy metal wastes in the soil after the experiment. We conclude that vermicomposted gneiss powder has potential for use in agriculture as a nutrient source and can improve soil chemical properties
Correlação entre o conteúdo inorgânico e a polimerização da matriz orgânica das resinas compostas para restaurações dentárias: uma revisão narrativa
Introduction: In recent years, resin-matrix composite materials have revealed a fast technological improvement for dental applications. However, there are still some drawbacks related to the chemical composition, polymerization, and mechanical properties of resin-matrix composites with consequences in long-term clinical success. Objective: This study aimed to perform a narrative review regarding the effects of inorganic fillers on the organic matrix polymerization of resin-matrix composites. Materials and Methods: A search was performed in PubMed using relevant related key terms related to the chemical composition, properties and polymerization of resin matrix composites. Relevant studies published between 2001 and 2021 were selected. Results: The studies included in the present research provided relevant information on the chemical composition and properties of resin composites and polymerization factors, including the time, wavelength mode, and equipment. Studies have reported that silica and silicate nano-scale particles improve light transmission through resin-matrix composites and the degree of conversion of monomers in the organic matrix. Micrometric particles with a high refractive index can decrease the degree of conversion of monomers in the organic matrix. Conclusion: The polymerization of resin-matrix composites is affected by light scattering due to the type of inorganic particles and the differences in refractive indexes of inorganic and organic contents.Introdução: Nos últimos anos, as resinas compostas têm sido melhoradas em termos tecnológicos, permitindo o
alcance de melhores prognósticos na medicina dentária. Entretanto, subsistem algumas limitações relacionadas com
a composição química e as propriedades das resinas compostas com consequências no sucesso clínico a longo prazo.
Objetivo: O objetivo deste trabalho foi realizar uma revisão narrativa sobre a influência da componente inorgânica na
polimerização da matriz orgânica das resinas compostas usadas para restauração dentária. Materiais e Métodos: A
pesquisa foi realizada na plataforma PubMed utilizando termos de pesquisa relacionados com a composição química,
propriedades e a polimerização das resinas compostas, para seleção de artigos relevantes ao tema. Resultados:
Os estudos identificados reportam diferentes fatores relacionados com a polimerização incluindo modo, tempo,
equipamento e a composição química das resinas compostas. Os estudos indicam que partículas nanométricas à
base de sílica ou silicatos promovem uma maior transmissão de luz à matriz orgânica o que favorece a polimerização
do material. Por outro lado, partículas micrométricas com um alto índice de refração podem diminuir o grau de
conversão dos monómeros da matriz orgânica. Conclusão: A polimerização das resinas compostas é afetada pela
dispersão da luz, devido ao tamanho das partículas inorgânicas e aos índices de refração da componente orgânica e
inorgânica. De fato, um maior controlo da composição química e do tamanho de partículas inorgânicas aumenta o
grau de polimerização das resinas compostas
Insights into the mechanism of MCT8 oligomerization
Mutations in the thyroid hormone transporter monocarboxylate transporter 8 (MCT8) result in MCT8 deficiency, characterized by severe intellectual and motor disability. The MCT8 protein is predicted to have 12 transmembrane domains (TMDs) and is expressed as monomers, homodimers, and homo-oligomers. This study aimed to delineate the mechanism o
Alterações Físicas Em Latossolos Cultivados Com Plantas De Cobertura Em Rotação Com Soja E Milho
This study was conducted to evaluate the effect of different covers, grown in rotation with soybean and corn on the physical attributes of two Oxisols. The experiments were installed in Votuporanga, SP, Brazil and Selvíria, MS, Brazil in March 2008, after conventional tillage. The experimental design was a randomized complete block with four replications, using the following cover crops at different amounts of seeds: Sorghum bicolor, Pennisetum americanum, S. sudanense, hybrid of S. bicolor with S. sudanense, Urochloa ruziziensis and a control with spontaneous vegetation. We evaluated the dry matter yield of different covers, and macroporosity, microporosity, total porosity and bulk density, in the layers of 0-0.05, 0.05-0.20 and 0.20-0.40 m. It concludes that, different covers plants and seed amounts used for grains, seeds and forage after two years did not cause effects on some soil physical properties of the two Oxisols.11314915
Estabilidade De Agregados Em Latossolos Sob Plantas De Cobertura Em Rotação Com Soja E Milho
The objective was to evaluate the effect of different covers on the stability of soil aggregates in two areas of Oxisols, grown in rotation with crops of soybean and corn. The experiments were installed in Votuporanga, São Paulo, Brazil and Selvíria, Mato Grosso do Sul, Brazil in March 2008. The experimental design was a randomized block with four replicates and the following cover crops in different spending ha-1 seeds, were the treatments: Sorghum bicolor, 6, 7 and 8 kg ha-1; Pennisetum americanum, 10, 15 and 20 kg ha-1; S. sudanense, 12, 15 and 18 kg ha-1; hybrid of S. bicolor and S. sudanense, 8, 9 and 10 kg ha-1; Urochloa ruziziensis, 8, 12 and 16 kg ha-1; plus, control treatment with spontaneous vegetation. We evaluated the dry matter yield of different covers and were separate classes of soil aggregates and calculated the average diameter. It is noted that the cover crops had similar behavior on aggregates stability in the surface layer, and in the greater depth, the S. sudanense was more efficient in improving the class mean diameter between 2.0-1.0 mm, in Votuporanga, and the P. americanum was more efficient from 4.0 to 2.0 mm and 2.0-1.0 mm in Selvíria. Lower spending seeds was more promising on aggregate stability.11315616
Acercamiento a la situacion socioeconomica de las comunidades campesinas del Departamento de Sucre desde la perspectiva del Programa Yuquero
An overview is given of the situation of farm communities in the dept. of Sucre, Colombia, where a cassava drying program operates. The lack of integration of the developmental activities carried out by different institutions is evident, indicating the need for greater participation in district planning. Since a trend to monocrop cassava was observed, more attention should be paid to agricultural diversification. An animal feed industry using dried cassava should be installed. Several technical aspects of agricultural production are also discussed such as mechanization, intercropping, plant density, improved technology, and income. Recommendations are also given regarding the current underutilization of the machinery of the existing agroindustries, the improvement of sanitary conditions in the plants, and the enforcement of basic industrial security measures. Product quality control should be conducted, especially regarding MC. Conditions favoring a greater participation of members in farmer organizations should be sought, in addition to enhanced institutional support in the search for a more integrated approach to regional development. (CIAT)Se presenta una percepcion global de la situacion de las comunidades campesinas del Depto. de Sucre, Colombia, donde se desarrolla un programa de secado de la yuca. Se destaca la falta de integracion de las actividades de desarrollo realizadas por diversas instituciones, lo cual indica la necesidad de una mayor participacion en la planificacion distrital. Puesto que se observo una tendencia al monocultivo de la yuca, se debe prestar mas atencion a la diversificacion agricola. Se sugiere instalar una planta para producir alimentos para animales que aproveche la yuca seca. Se discuten, ademas, varios aspectos tecnicos de la produccion agricola como mecanizacion, cultivos asociados, densidad de siembra, tecnologia mejorada e ingresos. Tambien se presentan recomendaciones sobre la actual subutilizacion de la maquinaria en las agroindustrias existentes, el mejoramiento de los servicios higienicos en las plantas y la implementacion de medidas basicas de seguridad industrial. Se debe efectuar un control de calidad del producto, especialmente en cuanto a CH. Se deben buscar las condiciones para fomentar mayor participacion de los socios en las organizaciones, ademas de incrementar el apoyo institucional en busca de un enfoque mas integrado de desarrollo a nivel regional. (CIAT
Insights into the mechanism of MCT8 oligomerization
Supplemental material related to this submitted article will be made available here
Transfer-matrix scaling from disorder-averaged correlation lengths for diluted Ising systems
A transfer matrix scaling technique is developed for randomly diluted
systems, and applied to the site-diluted Ising model on a square lattice in two
dimensions. For each allowed disorder configuration between two adjacent
columns, the contribution of the respective transfer matrix to the decay of
correlations is considered only as far as the ratio of its two largest
eigenvalues, allowing an economical calculation of a configuration-averaged
correlation length. Standard phenomenological-renormalisation procedures are
then used to analyse aspects of the phase boundary which are difficult to
assess accurately by alternative methods. For magnetic site concentration
close to , the extent of exponential behaviour of the curve
is clearly seen for over two decades of variation of . Close to the
pure-system limit, the exactly-known reduced slope is reproduced to a very good
approximation, though with non-monotonic convergence. The averaged correlation
lengths are inserted into the exponent-amplitude relationship predicted by
conformal invariance to hold at criticality. The resulting exponent
remains near the pure value (1/4) for all intermediate concentrations until it
crosses over to the percolation value at the threshold.Comment: RevTeX 3, 11 pages +5 figures, uuencoded, to appear in Phys. Rev. B
(1994), PUC/RJ preprin
Expanded Bed Adsorption Of Bromelain (e.c. 3.4.22.33) From Ananas Comosus Crude Extract
This work focuses on the adsorption of Bromelain in expanded bed conditions, such as the adsorption kinetics parameters. The adsorption kinetics parameters showed that after 40 minutes equilibrium was achieved and maximum adsorption capacity was 6.11 U per resin mL. However, the maximum adsorption capacity was only determined by measuring the adsorption isotherm. Only by the Langmuir model the maximum adsorption capacity, Qm, and dissociation constant, kd, values could be estimated as 9.18 U/mL and 0.591, respectively, at 25°C and 0.1 mol/L phosphate buffer pH 7.5. A column made of glass with an inner diameter of 1 cm was used for the expanded bed adsorption (EBA). The residence time was reduced 10 fold by increasing the expansion degree 2.5 times; nonetheless, the plate number (N) value was reduced only 2 fold. After adsorption, the bromelain was eluted in packed bed mode, with a downward flow. The purification factor was about 13 fold and the total protein was reduced 4 fold. 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