Series Of Light Flashes Research Articles

Appearance of an infalling star in black holes with multiple photon spheres

Photon spheres play a pivotal role in the imaging of luminous objects near black holes. In this paper, we examine observational appearances of a star freely falling in hairy black holes, which can possess one or two photon spheres outside the event horizon. When there exists a single photon sphere, the total luminosity measured by distant observers decreases exponentially with time at late times. Due to successive arrivals of photons orbiting around the photon sphere different times, a specific observer would see a series of light flashes with decreasing intensity, which share a similar frequency content. Whereas in the case with two photon spheres, photons temporarily trapped between the photon spheres can cause a peak of the total luminosity, which is followed by a slow exponential decay, at late times. In addition, these photons lead to one more series of light flashes seen by the specific observer.

Photoinduced electron transfer between cytochrome c peroxidase and horse cytochrome c labeled at specific lysines with (dicarboxybipyridine)(bisbipyridine)ruthenium(II)

The reactions of yeast cytochrome c peroxidase with horse cytochrome c derivatives labeled at specific lysine amino groups with (dicarboxybipyridine)(bisbipyridine)ruthenium(II) [Ru(II)] were studied by flash photolysis. All of the derivatives formed complexes with cytochrome c peroxidase compound I (CMPI) at low ionic strength (2 mM sodium phosphate, pH 7). Excitation of Ru(II) to Ru(II*) with a short laser flash resulted in electron transfer to the ferric heme group in cytochrome c, followed by electron transfer to the radical site in CMPI. This reaction was biphasic and the rate constants were independent of CMPI concentration, indicating that both phases represented intracomplex electron transfer from the cytochrome c heme to the radical site in CMPI. The rate constants of the fast phase were 5200, 19,000, 55,000, and 14,300 s-1 for the derivatives modified at lysines 13, 25, 27, and 72, respectively. The rate constants of the slow phase were 260, 520, 200, and 350 s-1 for the same derivatives. These results suggest that there are two binding orientations for cytochrome c on CMPI. The binding orientation responsible for the fast phase involves a geometry that supports rapid electron transfer, while that for the slow phase allows only slow electron transfer. Increasing the ionic strength up to 40 mM increased the rate constant of the slow phase and decreased that of the fast phase. A single intracomplex electron transfer phase with a rate constant of 2800 s-1 was observed for the lysine 72 derivative at this ionic strength. When a series of light flashes was used to titrate CMPI to CMPII, the reaction between the cytochrome c derivative and the Fe(IV) site in CMPII was observed. The rate constants for this reaction were 110, 250, 350, and 140 s-1 for the above derivatives measured in low ionic strength buffer.

Charge accumulation and photochemistry in leaves studied by thermoluminescence and delayed light emission

A major breakthrough in our understanding of how plants oxidize water to molecular O(2) was the discovery by P. Joliot and co-workers that the O(2) yield per flash, in a series of light flashes, oscillates with a periodicity of 4. This led to the concept by B. Kok and co-workers that these reactions involve accumulation of four positive charges in independent "O(2)-evolving centers," which undergo a series of changes in their redox state (the so-called S states). In the present paper, we have applied optical techniques (such as thermoluminescence and delayed light emission, both discovered by W. Arnold and co-workers) to monitor charge storage on the O(2)-evolving system in leaves from higher plants. We observed a period of four oscillations in both thermoluminescence and delayed light emission, with maxima on flashes 2 and 6, establishing a relationship with the charge accumulation process in photosynthesis. These measurements provided additional new information: the deactivation of the "O(2)-evolving centers," which cannot be measured by the O(2) method in the leaves, is in the 20- to 30-s range; and in the dark-adapted leaves, the secondary bound plastoquinone molecule (the so-called secondary electron acceptor Q(B)) is in equal concentration in its reduced and oxidized forms. The origin of thermoluminescence and delayed light emission, in terms of the recombination of charges on the O(2)-evolving and plastoquinone sides, is also discussed.

3D thin lead sheet compensating system.

The compensating filter system presented consists of a simulator mounted camera and light beam device. The light beam device produces a flash light beam 3-mm wide perpendicular to the x-ray axis. The distance between flashes can be varied from 0.5 to 2.5 cm in steps of 0.25 mm. An exposure of the patient in treatment position subject to a series of light flashes will produce a three-dimensional representation of the patient surface. This map is then properly enlarged. Lead sheets are cut and fixed to a Perspex plate which fits into a slot in the head of the accelerator. Regardless of energy, all compensators are made from 0.5-mm-thick lead sheets. To determine the proper distance between light flashes, measurements were performed in a water phantom for each x-ray energy to establish the equivalence of increasing numbers of layers of 0.5-mm lead. These measurements were compared to theoretical calculating using tissue maximum ratios, and finally checked against a wedged water phantom of 25 degrees as well as against a head and neck treatment field for the Alderson phantom. This way, a beam flattening of +/- 2% compared to the standard isodose lines was achieved.

The Metrical Structure of Macedonian Dance

METRICAL PATTERNS In essence, the theory to be presented here states that dance forms are generated by the encoding of abstract metrical patterns into an organized sequence of movements. The theory further suggests that a single set of abstract metrical patterns is actualized in the music and song lyrics, as well as in the dances, and that parallel, but not necessarily identical, sets of correspondence rules relate each form to the pattern. This hypothesis is derived from the linguistic analysis of poetic meters by Halle (1970a, 1970b), Halle and Keyser (1971), Kiparsky (1968), Maling (1973), and others. Halle and Keyser separate the study of meter into two parts, the analysis of abstract patterns and the discovery of correspondence rules which allow a particular instance to be viewed as an example of the pattern: To make clear our intention here let us consider a very simple example. One of the most rudimentary metrical patterns is one which consists of entities of a single type repeated some number of times. Examples of such patterns are given in (2): (2) XXX XXXX XXXXX XXX XXXX XXXXX XXX XXXX XXXXX 383 This content downloaded from 157.55.39.104 on Sun, 19 Jun 2016 06:50:07 UTC All use subject to http://about.jstor.org/terms ETHNOMUSICOLOGY, SEPTEMBER 1974 It is obvious that there is an infinity of arrangements of physical objects that can be said to realize one of these patterns-flowers in a flower bed, desks in a classroom, windows on the side of a house. A correspondence rule which said that each X was to be realized by a particular object (a flower, a desk, a window) would then tell us where to look for the patterns.... There is no need to instantiate the patterns by means of a static arrangement of objects, however; they could be equally well actualized by means of phenomena organized by a temporal sequence, as a series of drumbeats, a series of light flashes, a series of dance steps. All that would be required is that the correspondence rule be appropriately modified. (1971:140). The correspondence between the X's of a metrical pattern and the syllables of a line of poetry is illustrated by the following French verse: 0 bruit doux de la pluie Par terre et sur les toits! Pour un coeur qui s'ennuie O le chant de la pluite! (Verlaine; quoted in Halle 1970a:65) In this verse, the underlying metrical scheme is XXXXXX, and the correspondence rule is one syllable to each X. Additional verses, however, show that the first approximation of the mapping rule, postulating a one to one correspondence, is inadequate. Consider, for example, the first verse of the