An attempt is presented to explain the large difference in the
intensity, frequency range and number of radio activity events
following the large flares in the two complex active regions of June
1982 (NOAA Nos. 3763 and 3776). The topology of their local magnetic
fields in relation to the global field is discussed as one of the main
factors causing this effect.
The coffee plant is native to shaded environments and its seedlings are often produced in shaded nurseries. However, some nursery managers, in an effort to improve the acclimation of seedlings to field conditions after transplantation, produce seedlings in full sun exposure. In this study, the morphological and physiological parameters of arabica coffee (Coffea arabica) seedlings produced in full sun (T1) and in shade (T2) were examined. The biomass accumulation and relative growth rate of T1 and T2 seedlings were similar. The T1 seedlings had less biomass allocation to shoots, a lower leaf mass ratio and a lower leaf area ratio; however, they had a greater net assimilation rate (rate of increase in plant mass per unit leaf area), which was associated with a greater net photosynthetic rate. There were no alterations in the concentrations of total chlorophylls or in the chlorophyll a/b ratio when comparing T1 and T2 seedlings. No indications of photoinhibition or photooxidative damage were observed in the T1 plants, which were shown to have a more robust antioxidant system than the T2 plants. Seedlings transferred from shade to full sun (T3) were not capable of utilising the incident extra light to fix CO2. These seedlings showed a remarkable nocturnal retention of zeaxanthin and a significantly increased deepoxidation state of the xanthophyll cycle, even at predawn, but the activity of antioxidant enzymes was lower than in the T1 and T2 plants. Despite the acclimation capacity of T3 seedlings to the new light environment, they exhibited chronic photoinhibition and considerable photooxidative damage throughout the seven days following the transfer to full sun exposure. We further discuss the practical implications of producing coffee seedlings in full sunlight and under shade. and G. A. B. K. Moraes ... [et al.].
In this article we will describe a surprising observation that occurred in the construction of quadratic unramified extensions of a family of pure cubic number fields. Attempting to find an explanation will lead us on a magical mystery tour through the land of pure cubic number fields, Hilbert class fields, and elliptic curves.
N. N. Cencov wrote a commentary chapter included in the Appendix of the Russian translation of the Devroye and Györfi book [15] collecting some arguments supporting the <span class="tex">L<sub>1</sub></span> view of density estimation. The Cencov's work is available in Russian only and it hasn't been translated, so late Igor Vajda decided to translate the Cencov's paper and to add some remarks on the occasion of organizing the session "25 Years of the <span class="tex">L<sub>1</sub></span> Density Estimation" at the Prague Stochastics 2010 Symposium. In this paper we complete his task, i.e., we translate the Cencov's chapter and insert some remarks on the related literature focusing primarily on Igor's results. We would also like to acknowledge the excellent work of Alexandre Tsybakov who translated the Devroye and Györfi book in Russian, annotated it with valuable comments and included some related references published in Russian only.
The paper is concerned with generalized (i. e. monotone and possibly non-additive) measures. A discussion concerning the classification of these measures, according to the type and amount of non-additivity, is done. It is proved that λ-additive measures appear naturally as solutions of functional equations generated by the idea of (possible) non additivity.
In this paper, a theoretical approach of a wideband preamplifier using a high-end operation amplifier OPA847 will be presented. This device is designed to be used for a low noise, wide band measuring. The level of optimization is based on a noise model for the electrical part of the receiver. During the process of amplifier designing, all the noise components have been investigated separately, using operational amplifiers models. Although this preamplifier was designed to serve for the purposes of flame sensors evaluate, it can be also used to other purposes requiring wide band amplifier with low noise, under only a minimal modification. and V tomto příspěvku bych rád přiblížil teoretický postup návrhu
širokopásmového předzesilovače, využívajícího moderní integrovaný
předzesilovač OPA847, který je určen pro nízkošumová
měření. Stupeň optimalizace je založen na šumovém modelu pro
elektrickou část přijímače. Během návrhu zesilovače byla každá
šumová složka zkoumána zvlášť s využitím modelu operačního
zesilovače. Přestože byl tento předzesilovač navržen pro účely
měření detektorů plamene. Může být s výhodou využit všude jinde,
kde je vyžadován širokopásmový, nízkošumový předzesilovač a to
jen s minimálními úpravami.