1994 ◽  
Vol 144 ◽  
pp. 559-564
Author(s):  
P. Ambrož ◽  
J. Sýkora

AbstractWe were successful in observing the solar corona during five solar eclipses (1973-1991). For the eclipse days the coronal magnetic field was calculated by extrapolation from the photosphere. Comparison of the observed and calculated coronal structures is carried out and some peculiarities of this comparison, related to the different phases of the solar cycle, are presented.


2000 ◽  
Vol 179 ◽  
pp. 303-306
Author(s):  
S. D. Bao ◽  
G. X. Ai ◽  
H. Q. Zhang

AbstractWe compute the signs of two different current helicity parameters (i.e., αbestandHc) for 87 active regions during the rise of cycle 23. The results indicate that 59% of the active regions in the northern hemisphere have negative αbestand 65% in the southern hemisphere have positive. This is consistent with that of the cycle 22. However, the helicity parameterHcshows a weaker opposite hemispheric preference in the new solar cycle. Possible reasons are discussed.


1979 ◽  
Vol 44 ◽  
pp. 357-372
Author(s):  
Z. Švestka

The following subjects were discussed:(1)Filament activation(2)Post-flare loops.(3)Surges and sprays.(4)Coronal transients.(5)Disk vs. limb observations.(6)Solar cycle variations of prominence occurrence.(7)Active prominences patrol service.Of all these items, (1) and (2) were discussed in most detail and we also pay most attention to them in this report. Items (3) and (4) did not bring anything new when compared with the earlier invited presentations given by RUST and ZIRIN and therefore, we omit them.


Author(s):  
R. J. Lee ◽  
J. S. Walker

Electron microscopy (EM), with the advent of computer control and image analysis techniques, is rapidly evolving from an interpretative science into a quantitative technique. Electron microscopy is potentially of value in two general aspects of environmental health: exposure and diagnosis.In diagnosis, electron microscopy is essentially an extension of optical microscopy. The goal is to characterize cellular changes induced by external agents. The external agent could be any foreign material, chemicals, or even stress. The use of electron microscopy as a diagnostic tool is well- developed, but computer-controlled electron microscopy (CCEM) has had only limited impact, mainly because it is fairly new and many institutions lack the resources to acquire the capability. In addition, major contributions to diagnosis will come from CCEM only when image analysis (IA) and processing algorithms are developed which allow the morphological and textural changes recognized by experienced medical practioners to be quantified. The application of IA techniques to compare cellular structure is still in a primitive state.


During his lifetime, Nikolai Rimsky-Korsakov (1844–1908) was a composer whose work had great influence not only in his native Russia but also internationally. While he remains well-known in Russia—where many of his fifteen operas and various orchestral pieces are still in the standard repertoire—very little of his work is performed in the West today beyond Scheherezade and arrangements of The Flight of the Bumblebee. In Western writings, he appears mainly in the context of the Mighty Handful, a group of five Russian composers to which he belonged at the outset of his career. This book finally gives the composer center stage and due attention. In this book, Rimsky-Korsakov's major operas, The Snow Maiden, Mozart and Salieri, and The Golden Cockerel, receive multifaceted exploration and are carefully contextualized within the wider Russian culture of the era. The discussion of these operas is accompanied and enriched by the composer's letters to Nadezhda Zabela-Vrubel, the distinguished soprano for whom he wrote several leading roles. Other chapters look at more general aspects of Rimsky-Korsakov's work and examine his far-reaching legacy as a professor of composition and orchestration, including his impact on his most famous pupil Igor Stravinsky.


2014 ◽  
Vol 4 (2) ◽  
pp. 477-483
Author(s):  
Debojyoti Halder

Sunspots are temporary phenomena on the photosphere of the Sun which appear visibly as dark spots compared to surrounding regions. Sunspot populations usually rise fast but fall more slowly when observed for any particular solar cycle. The sunspot numbers for the current cycle 24 and the previous three cycles have been plotted for duration of first four years for each of them. It appears that the value of peak sunspot number for solar cycle 24 is smaller than the three preceding cycles. When regression analysis is made it exhibits a trend of slow rising phase of the cycle 24 compared to previous three cycles. Our analysis further shows that cycle 24 is approaching to a longer-period but with smaller occurrences of sunspot number.


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