scholarly journals Physical Classification of Short-Period Variables

1975 ◽  
Vol 67 ◽  
pp. 243-246
Author(s):  
D. H. P. Jones
Keyword(s):  
Light Curve ◽  
Light Variation ◽  
Typical Representative ◽  
Class A ◽  
Spectral Class ◽  
Short Period ◽  
Physical Classification

It is widely accepted that pulsating variables with periods less than 0.2 day fall into two distinct groups. These defined by Kukarkin et al. (1969) as, firstly,RRs:RR Lyrae type variables with the period not exceeding 0d.21 (dwarf Cepheids). Belong to the population of the disk, are absent in clusters. Their luminosity is 2m–3m fainter than the luminosity of RRab and RRc stars. A typical representative – SX Phe.and secondly,δSct:δScuti type stars. Pulsating variables of spectral class A (late sub-classes) and F, the amplitudes of light variation do not exceed, as a rule, 0m.1 (rarely up to 0m.3). The form of light curve strongly varies usually. According to many characteristics resemble dwarf Cepheids, but differ from them by the small amplitudes. Are met in the Hyades-type clusters. Similar to the RRs type stars their periods do not exceed 0d.2. A typical representative – δSct.

scholarly journals Observations and light curve solutions of the eclipsing binaries USNO-B1.0 1395-0370184 and USNO-B1.0 1395-0370731

2016 ◽  
pp. 27-32 ◽  
Author(s):  
D. Kjurkchieva ◽  
V.A. Popov ◽  
D. Vasileva ◽  
N. Petrov
Keyword(s):  
Light Curve ◽  
Eclipsing Binaries ◽  
Eclipsing Stars ◽  
System P ◽  
Photometric Observations ◽  
Short Period ◽  
Orbital Periods ◽  
Period System

We present follow-up photometric observations in Sloan filters g', i' of the newly discovered eclipsing stars USNO-B1.0 1395-0370184 and USNO-B1.0 1395-0370731. Our data revealed that their orbital periods are considerably bigger than the previous values. This result changed the classification of USNO-B1.0 1395-0370184 from ultrashort-period binary (P=0.197 d) to short-period system (P=0.251 d). The light curve solutions of our observations revealed that USNOB1.0 1395-0370184 and USNO-B1.0 1395-0370731 are overcontact binaries in which components are K dwarfs, close in masses and radii. The light curve distortions were reproduced by cool spots with angular radius of around 20?.

RSCVn Stars in the Southern Hemisphere

1979 ◽  
Vol 46 ◽  
pp. 371-384 ◽  
Author(s):  
J.B. Hearnshaw
Keyword(s):  
Light Curve ◽  
Southern Hemisphere ◽  
Orbital Period ◽  
Binary Stars ◽  
Small Amplitude ◽  
Light Variation ◽  
Orbital Phase

RSCVn stars are fully detached binary stars which show intrinsic small amplitude (up to 0.3 amplitude peak-to-peak) light variations, as well as, in most of the known cases, eclipses. The spectra are F to G, IV to V for the hotter component and usually KOIV for the cooler. They are also characterised by abnormally strong H and K emission from the cooler star, or, occasionally, from both components. The orbital and light curve periods are in the range 1 day to 2 weeks. An interesting feature is the migration of the light variations to earlier orbital phase, as the light variation period is shorter than the orbital period by a few parts in 10+4to a few parts in 10+3.

A 3-tier classification of cerebral arteriovenous malformations

2011 ◽  
Vol 114 (3) ◽  
pp. 842-849 ◽  
Author(s):  
Robert F. Spetzler ◽  
Francisco A. Ponce
Keyword(s):  
Surgical Outcomes ◽  
Arteriovenous Malformations ◽  
Neurological Deficits ◽  
Cerebral Arteriovenous Malformations ◽  
Pooled Data ◽  
Class A ◽  
Tier System ◽  
Class B ◽  
Class C

Object The authors propose a 3-tier classification for cerebral arteriovenous malformations (AVMs). The classification is based on the original 5-tier Spetzler-Martin grading system, and reflects the treatment paradigm for these lesions. The implications of this modification in the literature are explored. Methods Class A combines Grades I and II AVMs, Class B are Grade III AVMs, and Class C combines Grades IV and V AVMs. Recommended management is surgery for Class A AVMs, multimodality treatment for Class B, and observation for Class C, with exceptions to the latter including recurrent hemorrhages and progressive neurological deficits. To evaluate whether combining grades is warranted from the perspective of surgical outcomes, the 3-tier system was applied to 1476 patients from 7 surgical series in which results were stratified according to Spetzler-Martin grades. Results Pairwise comparisons of individual Spetzler-Martin grades in the series analyzed showed the fewest significant differences (p < 0.05) in outcomes between Grades I and II AVMs and between Grades IV and V AVMs. In the pooled data analysis, significant differences in outcomes were found between all grades except IV and V (p = 0.38), and the lowest relative risks were found between Grades I and II (1.066) and between Grades IV and V (1.095). Using the pooled data, the predictive accuracies for surgical outcomes of the 5-tier and 3-tier systems were equivalent (receiver operating characteristic curve area 0.711 and 0.713, respectively). Conclusions Combining Grades I and II AVMs and combining Grades IV and V AVMs is justified in part because the differences in surgical results between these respective pairs are small. The proposed 3-tier classification of AVMs offers simplification of the Spetzler-Martin system, provides a guide to treatment, and is predictive of outcome. The revised classification not only simplifies treatment recommendations; by placing patients into 3 as opposed to 5 groups, statistical power is markedly increased for series comparisons.

scholarly journals X-Ray Nova Flares

1975 ◽  
Vol 67 ◽  
pp. 501-508
Author(s):  
P. R. Amnuel ◽  
O. H. Guseinov
Keyword(s):  
Light Curve ◽  
Physical Nature ◽  
Dwarf Star ◽  
Optical Identification ◽  
X Ray ◽  
Spectral Class ◽  
Maximum Value ◽  
The Galaxy

In order to find out the physical nature of galactic X-ray sources, data on the variability of 24 sources during 1964–1971 have been investigated. The fluxes of 9 sources are found to be increasing to the maximum value (for several months) and then slowly decreasing (for 3 years). These 9 sources have been related by us to the class of X-ray Novae. The X-ray Nova synthetic light curve has been drawn from data of the fluxes of 9 discovered Novae. Assumptions have been made on the physical nature of the X-ray Novae. Between the flares the X-ray Novae may be weak X-ray sources with a luminosity of about 1034 erg s−1. During the flares the luminosity increases to about 1038 erg s−1. The number of X-ray sources in the Galaxy is about 103–104. The object of the optical identification may be a dwarf star of no earlier spectral class than F.

scholarly journals The Semantics of Trwm in Middle Welsh Prose

2018 ◽  
Vol 8 ◽  
pp. 89-107
Author(s):  
Elena Parina ◽  
Keyword(s):  
Short Period

Like its Goidelic cognate trom, analysed in Dereza (this volume), Welsh trwm is highly polysemous. In contrast to Dereza’s more general approach, I discuss here in detail the usage of this adjective in one relatively short period, based on the Welsh Prose 1300–1425 corpus (Luft et al. 2013). In order to make the Goidelic and Welsh data comparable, I analyse my data using the same classification of senses as Dereza. Despite some difficulties arising from the structure of the corpus used, I discuss the frequency of the usage within the four domains: experiential, parametrical, psycho-physiological and emotional. The last domain is the main focus of my attention due to the diversity of constructions in which trwm is thus used. I end by drawing some conclusions concerning the use of Celtic data in lexical typology.

scholarly journals On the Classification of Fake Information During the Coronavirus Pandemic

2021 ◽  
pp. 124-131
Author(s):  
Marina Zyryanova
Keyword(s):  
Social Networks ◽  
Information Source ◽  
Conspiracy Theory ◽  
Russian Regions ◽  
False Information ◽  
Public Response ◽  
Mass Consciousness ◽  
Short Period ◽  
Large Audience

This article presents the classification of fakes on grounds of the information source that underlies the occurrence of false information. The study was perfomed on the coronavirus fakes that spread in Russian Federation in March 2020 during the beginning of the coronavirus pandemic in our country. For the analysis, only those fakes were taken, which the Administrations of the Russian regions promptly denied in their official accounts on social networks. Based on this, only those fakes that caused the greatest public response were selected for analysis. In this article, the following types of fakes are distinguished: folklore, symmetric, interpretive, additional, and conspiracy. Folklore fakes in various variations reproduce the same motives and are associated with well-established ideas and stereotypes in the mass consciousness. Symmetrical fakes partially or completely transfer true facts from one territory (country, region) to another. They can also transfer information from one person (structure) to another (s). Interpretative fakes are associated with the incorrect interpretation of events, information disseminated, or decisions made by the authorities by individual individuals. Additional fakes for a short period of time continue the theme of previously thrown disinformation. Conspiracy fakes are associated with conspiracy theory, characterized by stuffing on a wide territory and a large audience This classification is not exhaustive and can be supplemented as new fakes appear and are studied. Also, within the framework of this article, recommendations are given on how to refute a particular fake, depending on its belonging to a particular type.

scholarly journals Continuous Free-Flow Fractionation of Cellular Constituents in Rat Bone Marrow

Blood ◽  
1965 ◽  
Vol 25 (1) ◽  
pp. 63-72 ◽  
Author(s):  
HOWARD C. MEL ◽  
LINDA T. MITCHELL ◽  
BO THORELL
Keyword(s):  
Bone Marrow ◽  
Cell Types ◽  
Single Cell Suspension ◽  
Physical Classification ◽  
Normal Rat ◽  
Good Repeatability ◽  
Different Cell Types ◽  
Stable Flow ◽  
Rat Bone

Abstract A single-cell suspension of normal rat bone marrow is prepared mechanically. This suspension is continuously fractionated in free solution, under sedimentation rate conditions, using 1 g. only. With a sample flow of 2.2 x 106 cells/minute and a 32-minute steady-state residence time in the stable-flow free boundary (STAFLO) flow-cell, the cells exit almost entirely into 7 of the 12 collection bottles. Maximum numbers of different cell types are observed, with good repeatability, in approximately descending order from top to bottom as follows: erythrocytes, "erythroblasts," "immatures," "myelocytes," and mature granulocytes. Major changes are effected relative to the starting marrow composition, and large relative enrichments are achieved for certain cell types. In addition to the rapid, mild, preparative aspect of this study, nominal sedimentation rates can be assigned for the different collection fractions, in the range of 3 x 105 to 4 x 106 svedbergs, thus making a start on this kind of simple physical classification of the cellular elements in this complex tissue.

Light-curve of van Gent's short-period variable

1931 ◽  
Vol 41 ◽  
pp. 89 ◽  
Author(s):  
Harold L. Alden
Keyword(s):  
Light Curve ◽  
Short Period ◽  
Period Variable
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