scholarly journals Ubiquitous C IV 1550 Variability in B and Be Stars

1987 ◽  
Vol 92 ◽  
pp. 286-288 ◽  
Author(s):  
G. Sonneborn ◽  
M.P. Garhart ◽  
C.A. Grady
Keyword(s):  
Time Scale ◽  
High Dispersion ◽  
Be Stars ◽  
Line Profiles ◽  
Standard Star ◽  
B Stars ◽  
Short And Long Term ◽  
Resonance Transitions ◽  
Long Term Behavior

Studies of line profile variability of the ultraviolet 1550 Angstrom resonance transitions of C IV in Be stars (Sonneborn et al. 1986; Grady, et al. 1986a,b) have prompted an investigation into the short- and long-term behavior of the C IV lines in other types of B stars. We present examples of two well-studied Be stars, Omega Orionis and 66 Ophiuchi, and two non-Be stars, Beta Cephei and the standard star Zeta Cassiopeiae. Zeta Cas is also known to be a 53 Per variable (see Cox 1983). The IUE SWP high-dispersion spectra of Beta Cep and Zeta Cas have been obtained from the IUE archives. It has been known for some years that the C IV line profiles in Beta Cep vary in a time scale of several days (Fishel and Sparks, 1980). However, it came as a surprise to discover C IV variability in Zeta Cas. Available data allow us to set an upper limit of several months for the time scale of Zeta Cas C IV variability. The principal difference between the C IV variability in Be and non-Be stars appears to be the magnitude and velocity range of the effect.

scholarly journals The Rate of Information Transfer of Naturalistic Stimulation by Graded Potentials

2003 ◽  
Vol 122 (2) ◽  
pp. 191-206 ◽  
Author(s):  
Mikko Juusola ◽  
Gonzalo G. de Polavieja
Keyword(s):  
Time Scale ◽  
Information Transfer ◽  
Bright Light ◽  
Scale Structure ◽  
Finite Duration ◽  
Adaptation Mechanisms ◽  
Short And Long Term ◽  
Signaling Strategies

We present a method to measure the rate of information transfer for any continuous signals of finite duration without assumptions. After testing the method with simulated responses, we measure the encoding performance of Calliphora photoreceptors. We find that especially for naturalistic stimulation the responses are nonlinear and noise is nonadditive, and show that adaptation mechanisms affect signal and noise differentially depending on the time scale, structure, and speed of the stimulus. Different signaling strategies for short- and long-term and dim and bright light are found for this graded system when stimulated with naturalistic light changes.

scholarly journals Observational Constraints on Cool Disk Models of Be Stars

1987 ◽  
Vol 92 ◽  
pp. 195-196
Author(s):  
A.M. Hubert ◽  
M. Floquet ◽  
J. Chauville ◽  
M.Th. Chambon
Keyword(s):  
Time Scale ◽  
Working Group ◽  
Active Phase ◽  
Observational Constraints ◽  
Be Stars ◽  
Phase 2 ◽  
Line Profiles ◽  
Additional Information ◽  
Long Time ◽  
History Of

At first we examine the main characteristics of 3 well-known shell stars (EW Lac, ζ Tau, 48 Lib) before and during their variable shell phase (long time scale V/R and RV cycles). For that we have investigated a) recent studies of our Meudon working group, based on long sequences of spectroscopic observations (Hubert et al. 1983, 1986a; Mon 1984) b) previous data found in the literature c) additional information by a reexamination of line profiles obtained from our material. For ζ Tau and 48 Lib the selected cycles have been chosen among the most representative ones in the history of their respective shell episode. For EW Lac, which entered an active phase in 1977, we have studied the only recently observed cycle of shell feature variations. A summary of the 3 V/R shell stars characteristics during 1) the pre variable shell phase 2) the variable shell phase is reported elsewhere (Hubert et al. 1986b); we only give here general trends of it, Table 1.

Failure of a Test Embankment On a Sensitive Champlain Clay Deposit

1974 ◽  
Vol 11 (1) ◽  
pp. 142-164 ◽  
Author(s):  
P. La Rochelle ◽  
B. Trak ◽  
F. Tavenas ◽  
M. Roy
Keyword(s):  
Research Program ◽  
Factor Of Safety ◽  
Soft Clay ◽  
New Approach ◽  
Short And Long Term ◽  
Undrained Strength ◽  
The Stability ◽  
Long Term Behavior ◽  
Test Embankment

The present paper reports on the failure of a test embankment built on a soft, sensitive, and cemented clay in Saint-Alban, Quebec. The embankment was built as a first stage of a research program aimed at studying the short and long term behavior of embankments on soft clay foundations.A complete description of the embankment, of the instrumentation, and of the failure is given, followed by the analysis of the failure performed on the basis of different assumptions of fill behavior and of vane strength values mobilized in the clay crust. The analyses show that the assumptions of full mobilization of friction in the fill seems to be the most representative of the fill behavior in the present case and that a suitable factor of safety is obtained only when a reduction of vane strength is assumed to act in the crust.A new approach based on the residual undrained strength is suggested and seems to offer some potential as a valuable means of analyzing the stability of embankments on clay foundations.

The effect of annealing on the short and long term behavior of PEEK

1990 ◽  
Vol 24 (6) ◽  
pp. 657-664 ◽  
Author(s):  
P. Y. Jar ◽  
H. H. Kausch ◽  
W. J. Cantwell ◽  
P. Davies ◽  
H. Richard
Keyword(s):  
Short And Long Term ◽  
Long Term Behavior

scholarly journals Strange Among the Strange: The B-emission Star γ Cassiopeiæ

2002 ◽  
Vol 187 ◽  
pp. 221-237 ◽  
Author(s):  
P. Harmanec
Keyword(s):  
Unsolved Problem ◽  
Central Star ◽  
Time Variability ◽  
Be Stars ◽  
Iras Source ◽  
B Stars ◽  
X Ray ◽  
Spectroscopic Binary ◽  
Present Understanding

Abstractγ Cas (HD 5394) is an important representative of Be stars, hot B stars exhibiting Balmer and other emission lines in their spectra at certain epochs. Its emission spectrum was observed as early as in 1863 and has undergone spectacular changes since then. γ Cas is also extremely interesting because it qualifies for several phenomenologically defined groups: it is a light and colour variable, long-term radial-velocity variable, X-ray source, IRAS source, rapid line-profile variable, a single-line spectroscopic binary and a central star of a reflection nebula.A critical compilation of the wealth of observational data on the star, with emphasis on its time variability on several time scales, as well as an estimate of the most probable values of all basic physical properties of the object is presented. It is pointed out that in spite of a large quantity of data, systematic and well-calibrated observations are still rather rare. The present understanding of the object is put into perspective of the more general – and as yet unsolved – problem of the formation of Be envelopes.

(Invited) Sulfur Poisoning of Ni-Based SOFC-Anodes – Short and Long Term Behavior

2017 ◽  
Vol 77 (10) ◽  
pp. 141-147 ◽  
Author(s):  
André Weber ◽  
Sebastian Dierickx ◽  
Niklas Russner ◽  
Ellen Ivers-Tiffée
Keyword(s):  
Sulfur Poisoning ◽  
Short And Long Term ◽  
Long Term Behavior

scholarly journals Effect of Strain Hardening and Rate Sensitivity on the Dynamic Growth of a Void in a Plastic Material

1992 ◽  
Vol 59 (1) ◽  
pp. 48-53 ◽  
Author(s):  
M. Ortiz ◽  
A. Molinari
Keyword(s):  
Strain Hardening ◽  
Plastic Material ◽  
Rate Sensitivity ◽  
Spherical Void ◽  
Hydrostatic Tension ◽  
The Matrix ◽  
Short And Long Term ◽  
Dynamic Growth ◽  
Long Term Behavior

The problem studied in this paper concerns the dynamic expansion of a spherical void in an unbounded solid under the action of remote hydrostatic tension. The void is assumed to remain spherical throughout the deformation and the matrix to be incompressible. The effects of inertia, strain hardening, and rate sensitivity on the short and long-term behavior of the void, as well as on its response to ramp loading, are investigated in detail.

scholarly journals Sofosbuvir protects Zika virus-infected mice from mortality, preventing short- and long-term sequela

2017 ◽  
Author(s):  
André C. Ferreira ◽  
Camila Z. Valle ◽  
Patricia A. Reis ◽  
Giselle Barbosa-Lima ◽  
Yasmine Rangel Vieira ◽  
...  
Keyword(s):  
Zika Virus ◽  
Neurological Disorders ◽  
Health Concern ◽  
Virus Challenge ◽  
Significant Public Health Concern ◽  
Significant Public Health ◽  
Short And Long Term ◽  
Long Term Behavior

ABSTRACTZika virus (ZIKV) caused significant public health concern, because of its association with congenital malformations, neurological disorders in adults and, more recently, with deaths. Considering the necessity to mitigate the cases ZIKV-associated diseases, antiviral interventions against this virus are an urgent necessity. Sofosbuvir, a drug in clinical use against Hepatitis C Virus (HCV), is among the FDA-approved substances endowed with anti-ZIKV activity. In this work, we further investigated the in vivo activity of sofosbuvir against ZIKV. Neonatal Swiss mice were infected with ZIKV (2 x 107 PFU) and treated with sofosbuvir at 20 mg/kg/day, a concentration compatible with pre-clinical development of this drug. We found that sofosbuvir reduced acute levels of ZIKV from 60 to 90 % in different anatomical compartments, such as in blood plasma, spleen, kidney and brain. Early treatment with sofosbuvir doubled the percentage and time of survival of ZIKV-infected animals, despite the aggressive virus challenge assayed and also prevented the acute neuromotor impairment triggered by the virus. On the long-term behavior analysis of ZIKV-associated sequelae, sofosbuvir prevented loss of hippocampal- and amygdala-dependent memory. Our results point out that sofosbuvir inhibits ZIKV replication in vivo, which is consistent with the prospective necessity of antiviral drugs to treat ZIKV-infected individuals.

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