880 research outputs found
Non-Markovian Dynamics of Quantum Discord
We evaluate the quantum discord dynamics of two qubits in independent and
common non-Markovian environments. We compare the dynamics of entanglement with
that of quantum discord. For independent reservoirs the quantum discord
vanishes only at discrete instants whereas the entanglement can disappear
during a finite time interval. For a common reservoir, quantum discord and
entanglement can behave very differently with sudden birth of the former but
not of the latter. Furthermore, in this case the quantum discord dynamics
presents sudden changes in the derivative of its time evolution which is
evidenced by the presence of kinks in its behavior at discrete instants of
time.Comment: 6 pages, 4 figure
Efecto de la frecuencia de riego sobre la calidad del tomate en la región costera del nordeste brasileño
El objetivo de este estudio fue evaluar la calidad de la fruta de los tomates para diferentes frecuencias de riego en dos años de cultivo en la región costera del nordeste brasileño. El experimento fue conducido durante el período de agosto a diciembre de 2011 y 2012 en el área experimental de la Estación Meteorológica de la Universidad Federal del Ceará, situada en la ciudad Fortaleza, nordeste brasileño. El sistema de riego utilizado fue localizado con goteros integrados de caudal nominal 4 L h . El diseño experimental fue con bloques al azar factorial de 6x4. Los tratamientos adoptados fueron: F2 (dosis de riego cada dos días), F3 (dosis de riego cada tres días), F4 (dosis de riego cada cuatro días), F5 (dosis de riego cada cinco días), F6 (dosis de riego cada seis días) y F7 (dosis de riego a cada siete días). La dosis de riego diaria se estimó mediante un balance de agua entre evapotranspiración del cultivo y precipitaciones efectivas en la zona de estudio. Esta dosis aplicada será acumulativa en función de la frecuencia de riego de cada prueba experimental. Al final del experimento, las variables analizadas fueron: la firmeza de la fruta (FF), los sólidos solubles (SS), la acidez titulable (AT), el pH y la relación SS / AT. El manejo del riego aplicado al cultivo del tomate ha demostrado ser beneficioso por sus efectos positivos en la mejora de la calidad de los frutos para la industria de transformación. Los resultados que comparan diferentes frecuencias de riego dieron información útil sobre la posibilidad de mejorar su calidad nutricional. El intervalo de riego de 7 días proporcionó frutos de mejor calidad para el procesamiento industrial, y un intervalo de riego menor proporcionó frutos con características óptimas para su consumo en fresco
Poliaminas na embriogênese somática em cenoura (Daucus carota L.)
The polyamines, putrescine (Put), Spermidine (Spd) and Spermine (Spm) are widely present in nature, performing an important role in various cellular events. Considering that polyamines take part of the embryogenic process, it is important to know the bases for these alterations in the metabolism. The objective of the present study was to observe the contents of polyamines during the different phases of somatic embryogenesis of carrot. Analyses were carried out, according to a modification of the method developed by Flores & Galston every 96 hours during 50 days from the culture of cell suspensions. The cells were provided from callus and inoculated in Murashige & Skoog (MS) medium which had been modified and added with 0.2 mg/l of 2,4-D and 0.1 mg/l of Idnetin during the first 14 days, whereas for the other days, they were kept in MS medium deprived of phytoregulators. The contents of polyamines varied during all the embryogenic process, when putrescine showed the most accumulated. These results suggest that the levels of Spermidine and spermine are reduced in relation to putrescine due to the intense use of Spd and Spm in the process of cell division and differentiation, whereas Put seems to have only the function of synthetizing the other two amines.As poliaminas, putrescina (put), espermidina (spd) e espermina (spm) são amplamente distribuídas na natureza, desempenhando importante papel em vários eventos celulares. Considerando que as poliaminas estão envolvidas no processo embriogênico, torna-se importante conhecer as bases para estas alterações no metabolismo. O objetivo do presente trabalho foi observar os teores de poliaminas durante as diferentes fases da embriogênese somátka da cenoura. As análises foram realizadas, através da modificação do método de Flores e Galston a cada 96 horas durante 50 dias da cultura de células em suspensão. As células foram obtidas a partir de calos e inoculadas em meio de Murashige & Skoog (MS), modificado e acrescido de 0,2 mg/l de 2,4-D e 0,1 mg/l de cinetina durante os primeiros 14 dias da cultura, sendo que no restante do período permaneceram em meio MS desprovido de fiorreguladores. Os teores de poliaminas oscilaram durante todo o processo embriogênico, sendo que a putrescina foi a que apresentou maior acúmulo. Estes resultados sugerem que os níveis de espermidina e espermina são reduzidos em relação a putrescina devido a intensa utilização da spd e spm no processo de divisão e diferenciação celular, enquanto que a put parece ter apenas a função de sintetizar as outras duas amidas
Superovulatory and embryo yielding in sheep using increased exposure time to progesterone associated with a GnRH agonist.
We consider models of Extended Gravity and in particular, generic models
containing scalar-tensor and higher-order curvature terms, as well as a model
derived from noncommutative spectral geometry. Studying, in the weak-field
approximation, the geodesic and Lense-Thirring processions, we impose
constraints on the free parameters of such models by using the recent
experimental results of the Gravity Probe B and LARES satellites.Comment: 17 pages, 2 figure
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