scholarly journals Omicron Andromedae Photometry, Polarimetry, and a Tentative Model of the Light Variability

1987 ◽  
Vol 92 ◽  
pp. 456-459
Author(s):  
K. Oláh ◽  
H. Božić ◽  
P. Hadrava ◽  
J. Horn ◽  
P. Koubský ◽  
...  
Keyword(s):  
Emission Line ◽  
Time Scale ◽  
Periodic Variation ◽  
Basic Information ◽  
Tentative Model ◽  
History Of ◽  
To Come ◽  
Photoelectric Observations ◽  
Light Variability

Basic information about the star o and (HR 8762, HD 217675-6) is a bright (V=3.55m, B-V=-0.11m U-B=-0.50m) B6 III-Ve star. Its emission-line and shell spectrum is known to come and go on a time scale of years. In fact, the presence of a strong shell spectrum misled the authors of the HD catalogue to assign the star two HD numbers.o and is a prototype of Be rapid light variables in the sense that it has the longest record of photoelectric monitoring which goes back to 1915! The long history of attempts to understand the variations of this star has recently been summarized by Harmanec (1983). Collecting and analyzing all historical photoelectric observations, Harmanec (1984) concluded that the light variations of o And can be understood as a superposition of a long-term cyclic (8.5y) variation with an amplitude over 0.1m (the star being faintest at the recorded shell maxima) and a rapid periodic variation with a period of 1.571272 days.

AI and HCI: Two Fields Divided by a Common Focus

AI Magazine ◽  
2009 ◽  
Vol 30 (4) ◽  
pp. 48 ◽  
Author(s):  
Jonathan Grudin
Keyword(s):  
Time Scale ◽  
Short Time Scale ◽  
Intelligent Behavior ◽  
History Of ◽  
Short Time ◽  
Competition For Resources

Although AI and HCI explore computing and intelligent behavior and the fields have seen some cross-over, until recently there was not very much. This article outlines a history of the fields that identifies some of the forces that kept the fields at arm’s length. AI was generally marked by a very ambitious, long-term vision requiring expensive systems, although the term was rarely envisioned as being as long as it proved to be, whereas HCI focused more on innovation and improvement of widely-used hardware within a short time-scale. These differences led to different priorities, methods, and assessment approaches.  A consequence was competition for resources, with HCI flourishing in AI winters and moving more slowly when AI was in favor. The situation today is much more promising, in part because of platform convergence: AI can be exploited on widely-used systems.

scholarly journals A study of many-year spectral variability of the Ae Herbig star HD 36112

2021 ◽  
Vol 2 (1) ◽  
pp. 21-25
Author(s):  
M.I. Fursyak ◽  
O.V. Kozlova
Keyword(s):  
Emission Line ◽  
Equivalent Width ◽  
Time Scale ◽  
Probable Mechanism ◽  
Circumstellar Disk ◽  
High Dispersion ◽  
Circumstellar Envelope ◽  
Spectral Variability ◽  
Resonance Doublet

We present the results of long-term high-dispersion spectral observations (R = 20000) of the Ae Herbig star HD 36112 in the regions of the Ha emission line and the NaI D resonance doublet lines. They show that parameters of the Ha emission line demonstrate complicated variability on several time scales: 1) variability from night to night caused by inhomogeneity of the circumstellar envelope; 2) variability on a time scale of about 1200d characterized by a variation of the equivalent width, intensity, and other emission parameters; 3) variability on a time scale of more than 4000d observed as a many-year trend in variations of parameters of the Ha emission line. We associate these results with variability of physical and kinematic conditions in the inner regions of the accretion disk and wind. The most probable mechanism of this variability is a process of planet formation in the circumstellar disk.

Middle and Upper Palaeolithic environments and the calibration of 14C dates beyond 10,000 BP

Antiquity ◽  
1998 ◽  
Vol 72 (275) ◽  
pp. 26-33 ◽  
Author(s):  
Tjeerd H. van Andel
Keyword(s):  
Magnetic Field ◽  
Time Scale ◽  
Archaeological Sites ◽  
Upper Palaeolithic ◽  
Upper Limit ◽  
History Of ◽  
Climatic History ◽  
Quaternary History ◽  
The Last Glacial

Advances in our understanding of the Quaternary history of the earth's magnetic field provide the means to correct the radiocarbon time-scale for long-term (millennia) deviations from the calendrical one beyond the upper limit of the tree-ring-based calibration. The conversion is essential when Middle and Upper Palaeolithic archaeological sites are to be placed within the context of the complex climatic history of the last glacial interval and following deglaciation.

scholarly journals Berlin Congress 1878 Through the Eyes of Phanariot Alexander Karateodori Pashi

2021 ◽  
Vol 14 (4) ◽  
pp. 7-25
Author(s):  
R. Mihneva ◽  
V. Kolev
Keyword(s):  
International Relations ◽  
Primary Source ◽  
The Balkans ◽  
Law Faculty ◽  
History Of ◽  
Balkan Region ◽  
Personal Physician ◽  
To Come ◽  
The Relationship

The article contributes to the historical literature on the Berlin Congress; it shows the events of the summer of 1878 through the eyes of the diplomats of the defeated Otto man Empire. The primary source for the article is the “Rapport” by the head of the Turkish delegation to the Сongress, Alexander Karathéodori Pasha (1833–1906), a Phanariote with Greek and Bulgarian roots, the son of the personal physician of Sultan Mahmud II and the first Ottoman lawyer. He graduated from the Sorbonne law faculty with a doctorate in law. Until recently, Turkish historians wrote about him more as a diplomat. However, in recent years, they started to pay attention to his extraordinary fate, the history of his family, in which there were many famous Phanariots. “Rapport” only in recent years began to attract the at tention of historians. The history of its creation is still unclear. It contains fascinating details of the relationship between representatives of a collective Europe at that time, the nature of their interests, and factors that outlined the fate of the Balkan region for decades to come. The report was written by Ottoman dignitaries when the Balkans finally became a “border area.” Its author noticed how the “big players” ’s geopolitical contradictions pushed the local people’s historical evolution along the “path” of future cataclysms. Alexander Karathéodori Pasha conveys, through seemingly minor details, the discord between the representatives of the “collective West” “and their desire to stop the attempts of the Ottoman Empire to follow the European paradigm of development. Against the background of the events in Berlin, Karathéodori eased the participants’ desires to start the quickest part of the “Ottoman inheritance” and drew attention to the beginning process of restructuring of international relations. He viewed the Berlin Congress analytically and realized its long-term implications.

scholarly journals Long-Term Evolution of Starspot and Chromospheric Activity and Short-Term Light Variability of HK Lacertae

1989 ◽  
Vol 104 (2) ◽  
pp. 135-138
Author(s):  
Katalin Olah
Keyword(s):  
Cycle Length ◽  
Periodic Variation ◽  
Short Term ◽  
Long Period ◽  
Chromospheric Activity ◽  
Term Evolution ◽  
Ubv Photometry ◽  
Light Variability ◽  
Photospheric Temperature

AbstractOn the basis of 11 years of UBV photometry the light and color variability of the long-period RS CVn binary HK Lac (KOIII) is discussed. From the U-B data, which reflect the chromospheric activity, a quasi-periodic variation with the cycle length of about 5.5 years is suspected. Less evidently, a 2.7 years long overall spot coverage cycle is seen from the V(max) data.No cyclic variation is found from the B-V data representing the photospheric temperature conditions, although there is an indication that the star was the reddest around 1985, when the chromospheric activity was in maximum.At that time, in late 1985, we observed the star on 6 nights in UBV color in order to detect short-term variability. Fluctuations up to 0.03 magn. on time scales of 20-30 minutes were likely present. The mplitude is the highest in U colour.

scholarly journals Late-Quaternary Vegetational and Climatic History of the Yellowstone/Grand Teton Region

1989 ◽  
Vol 13 ◽  
pp. 83-89
Author(s):  
Cathy Barnosky
Keyword(s):  
Time Scales ◽  
Plant Communities ◽  
Time Scale ◽  
Environmental Changes ◽  
Late Quaternary ◽  
Relative Sensitivity ◽  
Northern Rocky Mountains ◽  
History Of ◽  
Lake Systems

The research underway focuses on the vegetational history of the Greater Yellowstone Ecosystem and the response of plant communities to environmental changes of varying intensity and duration. Four studies are in progress and at different stages of completion. In two investigations, processes operating on time scales of centuries and millennia are being studied to reconstruct the long-term environmental changes of the last 14,000 years. In a third study, a time scale of decades or less helps to clarify the nature of Yellowstone's northern range prior to and since the establishment of the Park. Finally, focusing on a time scale of years or less, we are investigating the sedimentary inputs in the aftermath of the 1988 fires to determine the processes by which lake sediments record fire events. An examination of the paleoecologic record on these different time scales provides information on the relative sensitivity of plant communities and lake systems to long-term and short-term disturbances, and adds to our knowledge of the postglacial history of the northern Rocky Mountains.

The E-ring: interactions with plasma and implications for its evolution

1984 ◽  
Vol 75 ◽  
pp. 599-602
Author(s):  
T.V. Johnson ◽  
G.E. Morfill ◽  
E. Grun
Keyword(s):  
Time Scale ◽  
Particle Density ◽  
High Energy ◽  
Particle Removal ◽  
Density Region ◽  
Drag Forces ◽  
Orbit Evolution ◽  
History Of ◽  
Ring Particle ◽  
Ring Material

A number of lines of evidence suggest that the particles making up the E-ring are small, on the order of a few microns or less in size (Terrile and Tokunaga, 1980, BAAS; Pang et al., 1982 Saturn meeting; Tucson, AZ). This suggests that a variety of electromagnetic and plasma affects may be important in considering the history of such particles. We have shown (Morfill et al., 1982, J. Geophys. Res., in press) that plasma drags forces from the corotating plasma will rapidly evolve E-ring particle orbits to increasing distance from Saturn until a point is reached where radiation drag forces acting to decrease orbital radius balance this outward acceleration. This occurs at approximately Rhea's orbit, although the exact value is subject to many uncertainties. The time scale for plasma drag to move particles from Enceladus' orbit to the outer E-ring is ~104yr. A variety of effects also act to remove particles, primarily sputtering by both high energy charged particles (Cheng et al., 1982, J. Geophys. Res., in press) and corotating plasma (Morfill et al., 1982). The time scale for sputtering away one micron particles is also short, 102 - 10 yrs. Thus the detailed particle density profile in the E-ring is set by a competition between orbit evolution and particle removal. The high density region near Enceladus' orbit may result from the sputtering yeild of corotating ions being less than unity at this radius (e.g. Eviatar et al., 1982, Saturn meeting). In any case, an active source of E-ring material is required if the feature is not very ephemeral - Enceladus itself, with its geologically recent surface, appears still to be the best candidate for the ultimate source of E-ring material.

The long-term instability of the new generation hydrogen masers

2020 ◽  
pp. 35-38
Author(s):  
S.I. Donchenko ◽  
I.Y. Blinov ◽  
I.B. Norets ◽  
Y.F. Smirnov ◽  
A.A. Belyaev ◽  
...  
Keyword(s):  
Time Scale ◽  
Frequency Difference ◽  
Clock Frequency ◽  
Quantum Frequency ◽  
Frequency Standards ◽  
Quantum Frequency Standards ◽  
New Generation ◽  
Atomic Time

The latest changes in the algorithm for the formation of the international atomic time scale TAI are reported in terms of estimating the weights of the clocks involved in the formation of TAI. Studies of the characteristics of the long-term instability of new-generation hydrogen masers based on processing the results of the clock frequency difference with respect to TAI are performed. It has been confirmed that at present, new-generation hydrogen masers show significantly less long-term instability in comparison with quantum frequency standards ofsimilar and other types.

Atypical Femoral Fracture in McCune-Albright Syndrome

2020 ◽  
Vol 7 (3) ◽  
pp. 147-152
Author(s):  
Salman Ghaffari ◽  
◽  
Mehran Razavipour ◽  
Parastoo Mohammad Amini ◽  
◽  
...  
Keyword(s):  
Femoral Fracture ◽  
Dynamic Compression ◽  
Plate Fixation ◽  
Medullary Canal ◽  
Mccune Albright Syndrome ◽  
Café Au Lait Spots ◽  
History Of ◽  
Albright Syndrome ◽  
Mccune Albright

McCune-Albright Syndrome (MAS) is characterized by endocrinopathies, café-au-lait spots, and fibrous dysplasia. Bisphosphonates are the most prescribed treatment for reducing the pain but their long-term use has been associated with atypical fractures of cortical bones like femur in patients. We present a 23-year-old girl diagnosed with MAS. She had an atypical mid-shaft left femoral fracture that happened during simple walking. She also had a history of long-term use of alendronate. Because of the narrow medullary canal, we used 14 holes hybrid locking plate for the lateral aspect of the thigh to fix the fracture and 5 holes dynamic compression plate (instead of the intramedullary nail) in the anterior surface to double fix it, reducing the probability of device failure. With double plate fixation and discontinuation of alendronate, the complete union was achieved five months after surgery

European Integration

2020 ◽  
Author(s):  
Johann P. Arnason
Keyword(s):  
European Integration ◽  
Eastern European ◽  
The European Union ◽  
Historical Processes ◽  
History Of ◽  
External Conditions ◽  
Eastern European Countries ◽  
Totalitarian Regimes ◽  
The Eu

Different understandings of European integration, its background and present problems are represented in this book, but they share an emphasis on historical processes, geopolitical dynamics and regional diversity. The introduction surveys approaches to the question of European continuities and discontinuities, before going on to an overview of chapters. The following three contributions deal with long-term perspectives, including the question of Europe as a civilisational entity, the civilisational crisis of the twentieth century, marked by wars and totalitarian regimes, and a comparison of the European Union with the Habsburg Empire, with particular emphasis on similar crisis symptoms. The next three chapters discuss various aspects and contexts of the present crisis. Reflections on the Brexit controversy throw light on a longer history of intra-Union rivalry, enduring disputes and changing external conditions. An analysis of efforts to strengthen the EU’s legal and constitutional framework, and of resistances to them, highlights the unfinished agenda of integration. A closer look at the much-disputed Islamic presence in Europe suggests that an interdependent radicalization of Islamism and the European extreme right is a major factor in current political developments. Three concluding chapters adopt specific regional perspectives. Central and Eastern European countries, especially Poland, are following a path that leads to conflicts with dominant orientations of the EU, but this also raises questions about Europe’s future. The record of Scandinavian policies in relation to Europe exemplifies more general problems faced by peripheral regions. Finally, growing dissonances and divergences within the EU may strengthen the case for Eurasian perspectives.

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