186 research outputs found
Effect of space flight on sodium, copper, manganese and magnesium content in the skeletal bones
Sodium content decreased in the human skeletal bones and rose in the rat bones following space flight. In man copper content rose in the femoral bone and decreased in the vertebral body and the sternum, but was unchanged in the rest of the bones. Magnesium content was decreased in the femoral bone and the sternum, and in the vertebrae, but remained unchanged in the rest of the bones. Possible mechanisms of the changes detected are discussed
IRAS 19135+3937: An SRd variable as interacting binary surrounded by a circumbinary disc
Semi-regular (SR) variables are not a homogeneous class and their variability
is often explained due to pulsations and/or binarity. This study focuses on
IRAS 19135+3937, an SRd variable with an infra-red excess indicative of a dusty
disc. A time-series of high-resolution spectra, UBV photometry as well as a
very accurate light curve obtained by the Kepler satellite, allowed us to study
the object in unprecedented detail. We discovered it to be a binary with a
period of 127 days. The primary has a low surface gravity and an atmosphere
depleted in refractory elements. This combination of properties unambiguously
places IRAS 19135+3937 in the subclass of post-Asymptotic Giant Branch stars
with dusty discs.
We show that the light variations in this object can not be due to
pulsations, but are likely caused by the obscuration of the primary by the
circumbinary disc during orbital motion. Furthermore, we argue that the
double-peaked Fe emission lines provide evidence for the existence of a gaseous
circumbinary Keplerian disc inside the dusty disc. A secondary set of
absorption lines has been detected near light minimum, which we attribute to
the reflected spectrum of the primary on the disc wall, which segregates due to
the different Doppler shift. This corroborates the recent finding that
reflection in the optical by this type of discs is very efficient. The system
also shows a variable Halpha profile indicating a collimated outflow
originating around the companion. IRAS 19135+3937 thus encompasses all the
major emergent trends about evolved disc systems, that will eventually help to
place these objects in the evolutionary context.Comment: Accepted to MNRA
KNOWLEDGE HUB: SPIRAL MATRIX THINKING AS A COMMUNICATION TECHNOLOGY FOR INDIVIDUAL AND GROUP LEARNING IN ONE DRIVE AND WORD ONLINE
The article represents the modification of the Knowledge Hub communicative technique of teaching English and other disciplines based on the OneDrive\Word-online cloud service. Specific options for the organization of group work and individual activities are considered. The article highlights the advantage and the efficiency of teaching and learning by the BYOD (Bring Your Own Device) mode. The paper includes examples of organizing of mass support of the study of the course of English for Business and Entrepreneurship (MOOC-Coursera) and of information technology of the Humanities program in the computer class and relying on BYOD mobile Internet access of students
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