scholarly journals A Few Binary Star Puzzles for Roberto on the Occasion of His Birthday

2009 ◽  
Vol 26 (3) ◽  
pp. 372-378 ◽  
Author(s):  
George W. Preston
Keyword(s):  
Binary Star ◽  
Carbon Star ◽  
Spectroscopic Binaries ◽  
Velocity Variation ◽  
Time Interval ◽  
Parent Population ◽  
Velocity Amplitude ◽  
The Past ◽  
Binary Separation ◽  
Rr Lyrae

AbstractRadial-velocity observations accumulated during the past 16 years are used to derive a preliminary orbit for the CEMP star CS 22881–036. The velocity amplitude is very small. No velocity variation is found for three additional CEMP stars observed over roughly the same time interval. Searches for companions of two CEMP double-lined spectroscopic binaries and of the RR Lyrae star TY Gru are reviewed. A disparity between the period distribution of disk carbon-star binaries and that of their parent population of normal binaries can be attributed qualitatively to a decline in accreted mass with increasing binary separation. Finally, possible reasons for failure to find expected companions of CEMP stars are discussed.

scholarly journals Significant increase in quantity and quality of knee arthroplasty related research in KSSTA over the past 15 years

2021 ◽  
Author(s):  
Stephanie Kirschbaum ◽  
Thilo Kakzhad ◽  
Fabian Granrath ◽  
Andrzej Jasina ◽  
Jakub Oronowicz ◽  
...  
Keyword(s):  
Knee Arthroplasty ◽  
Special Topic ◽  
Computer Assisted ◽  
Time Interval ◽  
Search Term ◽  
Level Of Evidence ◽  
The Past ◽  
Patient Reported ◽  
Over Time ◽  
Number Of Authors

Abstract Purpose This study aimed to evaluate both publication and authorship characteristics in Knee Surgery, Sports Traumatology, Arthroscopy journal (KSSTA) regarding knee arthroplasty over the past 15 years. Methods PubMed was searched for articles published in KSSTA between January 1, 2006, and December 31st, 2020, utilising the search term ‘knee arthroplasty’. 1288 articles met the inclusion criteria. The articles were evaluated using the following criteria: type of article, type of study, main topic and special topic, use of patient-reported outcome scores, number of references and citations, level of evidence (LOE), number of authors, gender of the first author and continent of origin. Three time intervals were compared: 2006–2010, 2011–2015 and 2016–2020. Results Between 2016 and 2020, publications peaked at 670 articles (52%) compared with 465 (36%) published between 2011 and 2016 and 153 articles (12%) between 2006 and 2010. While percentage of reviews (2006–2010: 0% vs. 2011–2015: 5% vs. 2016–2020: 5%) and meta-analyses (1% vs. 6% vs. 5%) increased, fewer case reports were published (13% vs. 3% vs. 1%) (p < 0.001). Interest in navigation and computer-assisted surgery decreased, whereas interest in perioperative management, robotic and individualized surgery increased over time (p < 0.001). There was an increasing number of references [26 (2–73) vs. 30 (2–158) vs. 31 (1–143), p < 0.001] while number of citations decreased [30 (0–188) vs. 22 (0–264) vs. 6 (0–106), p < 0.001]. LOE showed no significant changes (p = 0.439). The number of authors increased between each time interval (p < 0.001), while the percentage of female authors was comparable between first and last interval (p = 0.252). Europe published significantly fewer articles over time (56% vs. 47% vs. 52%), whereas the number of articles from Asia increased (35% vs. 45% vs. 37%, p = 0.005). Conclusion Increasing interest in the field of knee arthroplasty-related surgery arose within the last 15 years in KSSTA. The investigated topics showed a significant trend towards the latest techniques at each time interval. With rising number of authors, the part of female first authors also increased—but not significantly. Furthermore, publishing characteristics showed an increasing number of publications from Asia and a slightly decreasing number in Europe. Level of evidence IV.

Data-driven modeling decadal-to-centennial ENSO variability and its response to external forcing

2021 ◽  
Author(s):  
Aleksei Seleznev ◽  
Dmitry Mukhin ◽  
Andrey Gavrilov ◽  
Alexander Feigin
Keyword(s):  
Co2 Concentration ◽  
Data Driven ◽  
Time Interval ◽  
Solar Forcing ◽  
Russian Science ◽  
Dynamical Mechanism ◽  
Enso Variability ◽  
The Past ◽  
Sst Variability ◽  
Data Driven Modeling

&lt;p&gt;We investigate the decadal-to-centennial ENSO variability based on nonlinear data-driven stochastic modeling. We construct data-driven model of yearly Ni&amp;#241;o-3.4 indices reconstructed from paleoclimate proxies based on three different sea-surface temperature (SST) databases at the time interval from 1150 to 1995 [1]. The data-driven model is forced by the solar activity and CO2 concentration signals. We find the persistent antiphasing relationship between the solar forcing and Ni&amp;#241;o-3.4 SST on the bicentennial time scale. The dynamical mechanism of such a response is discussed.&lt;/p&gt;&lt;p&gt;The work was supported by the Russian Science Foundation (Grant No. 20-62-46056)&lt;/p&gt;&lt;p&gt;1. Emile-Geay, J., Cobb, K. M., Mann, M. E., &amp; Wittenberg, A. T. (2013). Estimating Central Equatorial Pacific SST Variability over the Past Millennium. Part II: Reconstructions and Implications, Journal of Climate, 26(7), 2329-2352.&lt;/p&gt;

scholarly journals Five-Year Experience of Liver Transplant at Kerman University of Medical Sciences: Afzalipoor Hospital

2020 ◽  
Author(s):  
Masood Dehghani
Keyword(s):  
Liver Transplantation ◽  
Liver Transplant ◽  
Cross Sectional Study ◽  
Outcome Data ◽  
Time Interval ◽  
Cross Sectional ◽  
The Past ◽  
Transplantation Center ◽  
Set Up ◽  
End Stage

Introduction: The only option for treatment of end stage liver diseases is liver transplantation. Afzalipour Hospital in Kerman, Iran is the third largest liver transplantation center in Iran. In this study, the outcomes of this center have been studied during the past 5 years. Methods: In this cross-sectional study, the pre and post transplantation’s clinical, demographic and outcome data of all patients who received liver transplant at Afzalipour Hospital during the past 5 years have been collected and reviewed. SPSS software ver. 16 was used to analyze the data. Results: Forty-three patients have received liver transplantation during this time interval. The 3-year survival rate of patients was 77%. The most common cause of death was primary nonfunction graft after transplantation. The most common complication was acute rejection (15%), all of which were successfully treated with corticosteroids. Conclusion:  Due to increment of cases of acute and chronic liver failure in the community and since the final treatment of these cases is liver transplantation, so there is need to develop liver transplant centers in the future. Quantitative and qualitative study of the activity of centers based liver transplant in Iran is necessary to set up successful centers.

scholarly journals The Large Magellanic Cloud PN population

2015 ◽  
Vol 11 (A29B) ◽  
Author(s):  
Warren A. Reid
Keyword(s):  
Milky Way ◽  
Central Star ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Parent Population ◽  
The Past ◽  
Standard Candle ◽  
Evolutionary Paths ◽  
Stellar Density

AbstractThe Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) allow us to study late stellar evolution in environments that are respectively about a half and a quarter the metallicity of the Milky Way. With a known distance and low reddening, the LMC is an excellent environment to study PNe and conduct multiple studies. Over the past twelve months we have used the UKST Hα survey to complete our search for faint PNe in the outer most LMC beyond the 64 deg2area previously covered. Follow-up spectroscopy using AAOmega on the AAT and the 2.3-m telescope at Siding Spring Observatory have yielded a further 22 new LMC PNe while confirming the 8 previously known in the outer LMC. Medium- and high-resolution spectra have been used to measure fluxes and derive densities, mass and central star temperatures. A strong correlation is found between PNe and stellar density. This is visually displayed and given an empirical value of α = 1 PN / 2.5 × 106L⊙. The current [Oiii]-based PNLF, apart from providing an excellent standard candle, contains information about the parent population. The new PNLF, which extends down nine magnitudes, permits investigation of the faint end, the overall effects of internal extinction and provides clues to explain the insensitivity of the PNLF cutoff. When compared to the ionised density and mass of LMC PNe, the PNLF reveals it’s bimodal characteristics. Two separate evolutionary paths are evident for young, evolving PNe.

scholarly journals Precise Radial Velocities of F, G, K Dwarfs

1988 ◽  
Vol 132 ◽  
pp. 79-81
Author(s):  
Bruce Campbell ◽  
Gordon A. H. Walker
Keyword(s):  
Radial Velocities ◽  
Absorption Lines ◽  
Spectroscopic Binaries ◽  
Brown Dwarf ◽  
Dwarf Stars ◽  
Low Level ◽  
The Past ◽  
Velocity Variations

We have monitored changes in the radial velocities of 24 bright F, G and K dwarf stars (known spectroscopic binaries excluded) for the past six years at CFHT by imposing the absorption lines of HF gas in the spectra to act as wavelength fiducials. The average external error in the δ(velocities) which are based on some 16 stellar lines is 13 m/s corresponds to 0.6 micron in the spectrum or 0.04 of a diode spacing per line. Reductions are complete for 16 stars. There is no evidence for brown dwarf companions in the sample. Two previously unknown spectroscopic binaries were found, and seven stars show indications of significant, long-term, low-level velocity variations which could be interpreted as purturbations by companions of a few Jupiter masses with periods greater than 12 years except for γ Cep, which may have a period of 2.7 years, and ε Eri. Observing time has been guaranteed for at least two more years at CFHT.

scholarly journals The X-ray Radiation Mechanism of the Compact (Neutron) Binary Stars

1987 ◽  
Vol 125 ◽  
pp. 249-249
Author(s):  
Tong Yi ◽  
Fang Geng ◽  
Mao Xinjie
Keyword(s):  
Magnetic Field ◽  
Binary Stars ◽  
Hot Spots ◽  
Binary Star ◽  
Compact Star ◽  
Gravitational Acceleration ◽  
Radiation Mechanism ◽  
X Ray ◽  
The Past ◽  
Field Lines

Usually we think a X-ray source may be a compact(neutron) binary star on which the X-ray radiation might be generated by gravitational acceleration for the particles coming from the primary and going along magnetic field lines of the compact star to the poles. But, in the past, people don't consider well the problem of particle acceleration. It seems to be simplified for the situation only to consider the gravitation effect, because some electric-magnetic effect in a strong magnetic field could not be neglected. However, it is unreasonable to neglect the plasma turbulent waves in an electric-magnetic field, because strong enough turbulent waves such as Alfven waves, whistlers generated nearby the surface of neutron stars probably contribute energy to accelerate particles, which may be more important than gravitation sometimes. For a binary system with a neutron star if ion number density N > 1017 /cm3 in its surface atmosphere, the turbulent wavess will be stimulated that will accelerate the particles reaching a speed over 108cm/s. they strike the atmosphere of the compact star in the system, so that a shock wave is formed which turns part of kinetic energy to heat to form hot spots of about 108K to emit X-ray.

scholarly journals A simple metric to quantify seismicity clustering

2010 ◽  
Vol 17 (4) ◽  
pp. 293-302 ◽  
Author(s):  
N. F. Cho ◽  
K. F. Tiampo ◽  
S. D. Mckinnon ◽  
J. A. Vallejos ◽  
W. Klein ◽  
...  
Keyword(s):  
Physical Meaning ◽  
Finite Time ◽  
Metastable Equilibrium ◽  
Lower Sensitivity ◽  
Time Interval ◽  
Finite Time Interval ◽  
Time Intervals ◽  
The Past ◽  
Local Clustering ◽  
Over Time

Abstract. The Thirulamai-Mountain (TM) metric was first developed to study ergodicity in fluids and glasses (Thirumalai and Mountain, 1993) using the concept of effective ergodicity, where a large but finite time interval is considered. Tiampo et al. (2007) employed the TM metric to earthquake systems to search for effective ergodic periods, which are considered to be metastable equilibrium states that are disrupted by large events. The physical meaning of the TM metric for seismicity is addressed here in terms of the clustering of earthquakes in both time and space for different sets of data. It is shown that the TM metric is highly dependent not only on spatial/temporal seismicity clustering, but on the past seismic activity of the region and the time intervals considered as well, and that saturation occurs over time, resulting in a lower sensitivity to local clustering. These results confirm that the TM metric can be used to quantify seismicity clustering from both spatial and temporal perspectives, in which the disruption of effective ergodic periods are caused by the agglomeration of events.

scholarly journals The Mysterious 14C Decline

Radiocarbon ◽  
2009 ◽  
Vol 51 (1) ◽  
pp. 109-119 ◽  
Author(s):  
Wallace Broecker
Keyword(s):  
Age Differences ◽  
Radiocarbon Dating ◽  
Progressive Increase ◽  
Time Interval ◽  
Last Deglaciation ◽  
Polar Ice ◽  
Radiocarbon Age ◽  
Surface Ocean ◽  
The Past ◽  
The Last Deglaciation

Fundamental to the field of radiocarbon dating is not only the establishment of the temporal record of the calendar age-radiocarbon age offsets but also the development of an understanding of their cause. Although part of the decline in the magnitude of this offset over the past 40,000 can be explained by a drop in 14C production rate associated with a progressive increase in the strength of the Earth's magnetic shielding, it is clear that changes in the distribution of 14C among the Earth's active carbon reservoirs are also required. In particular, the steep 15% decline in the 14C to C ratio in atmospheric CO2 and surface ocean ΣCO2, which occurred in a 3 kyr-duration interval marking the onset of the last deglaciation, appears to require that a very large amount (at least 5000 gigatons) of 14C-deficient carbon was transferred to or within the ocean during this time interval. As no chemical or stable isotope anomaly associated with this injection appears in either the marine sediment or polar ice records, this injection must involve a transfer within the ocean (i.e. a mixing of 2 ocean reservoirs, one depleted in 14C and the other enriched in 14C). Although evidence for the existence of a salt-stabilized glacial-age abyssal ocean reservoir exists, a search based on benthic-planktic age differences and 13C measurements appears to place a limit on its size well below that required to account for the steep 14C decline.

GEOPHYSICAL RESEARCH & PROGRESS IN EXPLORATION, 1965–1968

Geophysics ◽  
1969 ◽  
Vol 34 (2) ◽  
pp. 145-154
Author(s):  
P. C. Wuenschel ◽  
S. Treitel ◽  
E. A. Flinn ◽  
G. V. Keller ◽  
G. R. Pickett
Keyword(s):  
Progress Report ◽  
Research Progress ◽  
Time Interval ◽  
Geophysical Research ◽  
The Past

This is a progress report on developments in geophysical research and progress in exploration during the time interval from 1965 to 1968. It is the seventh treatment of this type prepared by the members of the society in the past 13 years.

scholarly journals In-vitro hemolysis and its financial impact using different blood collection systems

2015 ◽  
Vol 0 (0) ◽  
Author(s):  
Janne Cadamuro ◽  
Georg Martin Fiedler ◽  
Cornelia Mrazek ◽  
Thomas Klaus Felder ◽  
Hannes Oberkofler ◽  
...  
Keyword(s):  
Financial Impact ◽  
Blood Collection ◽  
Laboratory Diagnostics ◽  
Time Interval ◽  
Time Intervals ◽  
Mean Values ◽  
The Past ◽  
Collection Tube ◽  
Blood Collection Tube

AbstractHemolytic specimens are among the most challenging preanalytical issues in laboratory diagnostics. The type of blood collection tube in use is claimed to influence in vitro hemolysis. We aimed to examine this hypothesis and estimate the respective financial impact, evaluating routine blood samples from the past 4 years.A total of 47,820 hemolysis index (HI) values from five different time intervals (IV1–IV5) were compared against each other, representing the following tubes: IV1-Sarstedt Monovette; IV2-8 mL/16×100 mm Greiner BioOne (GBO) Vacuette; IV3/IV4-5 mL/16×100 mm GBO Vacuette; IV5-4.5 mL/13×75 mm GBO Vacuette. For estimation of the economic impact, material, personnel and analytical costs were calculated.HI mean values in time interval IV2 were significantly higher than in all other intervals, while mean values amongst all other intervals were comparable. The number of moderately and severely hemolyzed samples increased with incrementing vacuum. Overall comparable costs between intervals IV1 and IV5 were €11,370, €14,045, €12,710, €11,213 and €8138 per 10,000 samples, respectively.Aspiration tubes and low vacuum tubes show comparable hemolysis rates. Increasing vacuum levels are associated with higher hemolysis rates. By decreasing in vitro hemolysis, financial savings up to €5907 per 10,000 samples could be gained.

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