scholarly journals Planetary Dynamics in the α Centauri System: Lyapunov Spectra and Long-term Behaviour

2011 ◽  
Vol 7 (S282) ◽  
pp. 450-451
Author(s):  
E. A. Popova ◽  
I. I. Shevchenko
Keyword(s):  
Statistical Analysis ◽  
Initial Data ◽  
Planetary Motion ◽  
Fine Grid ◽  
Data Space ◽  
Lyapunov Spectra ◽  
Planetary Dynamics ◽  
The Stability ◽  
Central Stars

AbstractThe stability of planetary motion in the binary system α Cen A–B is studied. Lyapunov spectra of the motion of the system with a single massive planet are computed on a fine grid of the initial data, and, by means of statistical analysis of the obtained data arrays, chaotic domains are identified in the “pericentric distance — eccentricity” initial data space for the planetary orbit. Association with the initial data domains for the orbits exhibiting close encounters with central stars and for the orbits exhibiting long-term escape is investigated.

Stability of Transaction Fees in Bitcoin: A Supply and Demand Perspective

MIS Quarterly ◽  
2021 ◽  
Vol 45 (2) ◽  
pp. 563-692 ◽  
Author(s):  
Noyan Ilk ◽  
Guangzhi Shang ◽  
Shaokun Fan ◽  
J. Leon Zhao
Keyword(s):  
Demand Curve ◽  
Supply And Demand ◽  
Ceteris Paribus ◽  
Efficient Manner ◽  
Business World ◽  
Academic Effort ◽  
Data Space ◽  
Transaction Fees ◽  
The Stability

Cryptocurrencies such as Bitcoin are breakthrough financial technologies that promise to revolutionize the digital economy. Unfortunately, their long-term adoption in the business world is imperiled by a lack of stability that manifests as dramatic swings in transaction fees and severe participant dissatisfaction. To date, there has been little academic effort to study how system participants react to volatility in fee movements. Our study addresses this research gap by conceptualizing the Bitcoin platform as a data space market and studying how market equilibrium forms between users who demand data space while trying to avoid transaction delays, and miners who supply data space while trying to maximize fee revenues. Our empirical analysis based on past bitcoin transactions reveals the existence of a relatively flat downward-sloping demand curve and a much steeper upward-sloping supply curve. Regarding users, the inelastic nature of demand signals the utility of Bitcoin as a niche platform for transactions that are otherwise difficult to conduct. This result challenges the belief that users may easily abandon Bitcoin technology given rising transaction costs. We also find that the use of bitcoins as a trading asset is associated with higher levels of tolerance to fees. Regarding miners, the comparatively elastic nature of supply indicates that higher fees stimulate mining by a larger magnitude than suppressing demand. This finding implies that, ceteris paribus, the Bitcoin system turns to self-regulate transaction fees in an efficient manner. Our work has implications for the management of congestion in blockchain-based systems and more broadly for the stability of cryptocurrency markets.

The Stability of the WHO Reference Thromboplastin NIBS & C 67/40

1979 ◽  
Vol 42 (04) ◽  
pp. 1135-1140 ◽  
Author(s):  
G I C Ingram
Keyword(s):  
Human Brain ◽  
Collaborative Study ◽  
Calibration Constant ◽  
Long Term Stability ◽  
Freeze Dried ◽  
Show Evidence ◽  
Human Material ◽  
Reference Preparation ◽  
The Stability

SummaryThe International Reference Preparation of human brain thromboplastin coded 67/40 has been thought to show evidence of instability. The evidence is discussed and is not thought to be strong; but it is suggested that it would be wise to replace 67/40 with a new preparation of human brain, both for this reason and because 67/40 is in a form (like Thrombotest) in which few workers seem to use human brain. A �plain� preparation would be more appropriate; and a freeze-dried sample of BCT is recommended as the successor preparation. The opportunity should be taken also to replace the corresponding ox and rabbit preparations. In the collaborative study which would be required it would then be desirable to test in parallel the three old and the three new preparations. The relative sensitivities of the old preparations could be compared with those found in earlier studies to obtain further evidence on the stability of 67/40; if stability were confirmed, the new preparations should be calibrated against it, but if not, the new human material should receive a calibration constant of 1.0 and the new ox and rabbit materials calibrated against that.The types of evidence available for monitoring the long-term stability of a thromboplastin are discussed.

Symmetrizable Difference Dchemes

2005 ◽  
Vol 5 (1) ◽  
pp. 3-50 ◽  
Author(s):  
Alexei A. Gulin
Keyword(s):  
Initial Data ◽  
Difference Scheme ◽  
Difference Schemes ◽  
Time Dependent ◽  
Stability Boundaries ◽  
Typical Representative ◽  
Variable Weight ◽  
The Stability ◽  
Conditions Of Stability ◽  
The Right

AbstractA review of the stability theory of symmetrizable time-dependent difference schemes is represented. The notion of the operator-difference scheme is introduced and general ideas about stability in the sense of the initial data and in the sense of the right hand side are formulated. Further, the so-called symmetrizable difference schemes are considered in detail for which we manage to formulate the unimprovable necessary and su±cient conditions of stability in the sense of the initial data. The schemes with variable weight multipliers are a typical representative of symmetrizable difference schemes. For such schemes a numerical algorithm is proposed and realized for constructing stability boundaries.

Application of the method of mathematical modeling for forecasting channel deformations at the underwater crossing of the main pipeline

2020 ◽  
Vol 10 (6) ◽  
pp. 599-609
Author(s):  
Valery А. Gruzdev ◽  
◽  
Georgy V. Mosolov ◽  
Ekaterina A. Sabayda ◽  
◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Roughness Coefficient ◽  
Computational Domain ◽  
Channel Deformations ◽  
Geological Surveys ◽  
Kuban River ◽  
The Stability ◽  
Protective Structures

In order to determine the possibility of using the method of mathematical modeling for making long-term forecasts of channel deformations of trunk line underwater crossing (TLUC) through water obstacles, a methodology for performing and analyzing the results of mathematical modeling of channel deformations in the TLUC zone across the Kuban River is considered. Within the framework of the work, the following tasks were solved: 1) the format and composition of the initial data necessary for mathematical modeling were determined; 2) the procedure for assigning the boundaries of the computational domain of the model was considered, the computational domain was broken down into the computational grid, the zoning of the computational domain was performed by the value of the roughness coefficient; 3) the analysis of the results of modeling the water flow was carried out without taking the bottom deformations into account, as well as modeling the bottom deformations, the specifics of the verification and calibration calculations were determined to build a reliable mathematical model; 4) considered the possibility of using the method of mathematical modeling to check the stability of the bottom in the area of TLUC in the presence of man-made dumping or protective structure. It has been established that modeling the flow hydraulics and structure of currents, making short-term forecasts of local high-altitude reshaping of the bottom, determining the tendencies of erosion and accumulation of sediments upstream and downstream of protective structures are applicable for predicting channel deformations in the zone of the TLUC. In all these cases, it is mandatory to have materials from engineering-hydro-meteorological and engineering-geological surveys in an amount sufficient to compile a reliable mathematical model.

Influence of internal and external risks on sustainability of financial system of Аltai krai

2018 ◽  
Vol 35 (4) ◽  
pp. 133-136
Author(s):  
R. N. Ibragimov
Keyword(s):  
Sustainable Development ◽  
Financial Stability ◽  
Management Strategy ◽  
Financial System ◽  
Risk Management Strategy ◽  
The Sustainable Development ◽  
The Stability ◽  
The Impact

The article examines the impact of internal and external risks on the stability of the financial system of the Altai Territory. Classification of internal and external risks of decline, affecting the sustainable development of the financial system, is presented. A risk management strategy is proposed that will allow monitoring of risks, thereby these measures will help reduce the loss of financial stability and ensure the long-term development of the economy of the region.

Comparative Analysis of Patients with Robotic Hiatal Hernia Repairs with and without Collis Gastroplasty

2021 ◽  
pp. 000313482198905
Author(s):  
John A. Perrone ◽  
Stephanie Yee ◽  
Manrique Guerrero ◽  
Antai Wang ◽  
Brian Hanley ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Statistical Analysis ◽  
Hospital Stay ◽  
Hiatal Hernia ◽  
Collis Gastroplasty ◽  
Significant Difference ◽  
Related Quality

Introduction After extensive mediastinal dissection fails to achieve adequate intra-abdominal esophageal length, a Collis gastroplasty(CG) is recommended to decrease axial tension and reduce hiatal hernia recurrence. However, concerns exist about staple line leak, and long-term symptoms of heartburn and dysphagia due to the acid-producing neoesophagus which lacks peristaltic activity. This study aimed to assess long-term satisfaction and GERD-related quality of life after robotic fundoplication with CG (wedge fundectomy technique) and to compare outcomes to patients who underwent fundoplication without CG. Outcomes studied included patient satisfaction, resumption of proton pump inhibitors (PPI), length of surgery (LOS), hospital stay, and reintervention. Methods This was a single-center retrospective analysis of patients from January 2017 through December 2018 undergoing elective robotic hiatal hernia repair and fundoplication. 61 patients were contacted for follow-up, of which 20 responded. Of those 20 patients, 7 had a CG performed during surgery while 13 did not. There was no significant difference in size and type of hiatal hernias in the 2 groups. These patients agreed to give their feedback via a GERD health-related quality of life (GERD HRQL) questionnaire. Their medical records were reviewed for LOS, length of hospital stay (LOH), and reintervention needed. Statistical analysis was performed using SPSS v 25. Satisfaction and need for PPIs were compared between the treatment and control groups using the chi-square test of independence. Results Statistical analysis showed that satisfaction with outcome and PPI resumption was not significantly different between both groups ( P > .05). There was a significant difference in the average ranks between the 2 groups for the question on postoperative dysphagia on the follow-up GERD HRQL questionnaire, with the group with CG reporting no dysphagia. There were no significant differences in the average ranks between the 2 groups for the remaining 15 questions ( P > .05). The median LOS was longer in patients who had a CG compared to patients who did not (250 vs. 148 min) ( P = .01). The LOH stay was not significantly different ( P > .05) with a median length of stay of 2 days observed in both groups. There were no leaks in the Collis group and no reoperations, conversions, or blood transfusions needed in either group. Conclusion Collis gastroplasty is a safe option to utilize for short esophagus noted despite extensive mediastinal mobilization and does not adversely affect the LOH stay, need for reoperation, or patient long-term satisfaction.

Long-term vegetation restoration promotes the stability of the soil micro-food web in the Loess Plateau in North-west China

CATENA ◽  
2021 ◽  
Vol 202 ◽  
pp. 105293
Author(s):  
Yang Wu ◽  
WenJing Chen ◽  
Wulan Entemake ◽  
Jie Wang ◽  
HongFei Liu ◽  
...  
Keyword(s):  
Food Web ◽  
Loess Plateau ◽  
Vegetation Restoration ◽  
The Loess Plateau ◽  
West China ◽  
North West ◽  
The Stability

scholarly journals An unusually low density ultra-short period super-Earth and three mini-Neptunes around the old star TOI-561

2020 ◽  
Author(s):  
G Lacedelli ◽  
L Malavolta ◽  
L Borsato ◽  
G Piotto ◽  
D Nardiello ◽  
...  
Keyword(s):  
Transit Time ◽  
Time Variation ◽  
Planetary System ◽  
Radial Velocities ◽  
Low Density ◽  
Outer Planets ◽  
Short Period ◽  
The Stability

Abstract Based on HARPS-N radial velocities (RVs) and TESS photometry, we present a full characterisation of the planetary system orbiting the late G dwarf After the identification of three transiting candidates by TESS, we discovered two additional external planets from RV analysis. RVs cannot confirm the outer TESS transiting candidate, which would also make the system dynamically unstable. We demonstrate that the two transits initially associated with this candidate are instead due to single transits of the two planets discovered using RVs. The four planets orbiting TOI-561 include an ultra-short period (USP) super-Earth (TOI-561 b) with period Pb = 0.45 d, mass Mb = 1.59 ± 0.36 M⊕ and radius Rb = 1.42 ± 0.07 R⊕, and three mini-Neptunes: TOI-561 c, with Pc = 10.78 d, Mc = 5.40 ± 0.98 M⊕, Rc = 2.88 ± 0.09 R⊕; TOI-561 d, with Pd = 25.6 d, Md = 11.9 ± 1.3 M⊕, Rd = 2.53 ± 0.13 R⊕; and TOI-561 e, with Pe = 77.2 d, Me = 16.0 ± 2.3 M⊕, Re = 2.67 ± 0.11 R⊕. Having a density of 3.0 ± 0.8 g cm−3, TOI-561 b is the lowest density USP planet known to date. Our N-body simulations confirm the stability of the system and predict a strong, anti-correlated, long-term transit time variation signal between planets d and e. The unusual density of the inner super-Earth and the dynamical interactions between the outer planets make TOI-561 an interesting follow-up target.

scholarly journals Effect of Photoinitiator on Precursory Stability and Curing Depth of Thiol-Ene Clickable Gelatin

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1877
Author(s):  
Kai-Hung Yang ◽  
Gabriella Lindberg ◽  
Bram Soliman ◽  
Khoon Lim ◽  
Tim Woodfield ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Visible Light ◽  
Rheological Properties ◽  
Swelling Ratio ◽  
Sodium Persulfate ◽  
Photo Polymerization ◽  
Gelation Kinetics ◽  
The Stability ◽  
Over Time

Recent advances highlight the potential of photopolymerizable allylated gelatin (GelAGE) as a versatile hydrogel with highly tailorable properties. It is, however, unknown how different photoinitiating system affects the stability, gelation kinetics and curing depth of GelAGE. In this study, sol fraction, mass swelling ratio, mechanical properties, rheological properties, and curing depth were evaluated as a function of time with three photo-initiating systems: Irgacure 2959 (Ig2959; 320–500 nm), lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP; 320–500 nm), and ruthenium/sodium persulfate (Ru/SPS; 400–500 nm). Results demonstrated that GelAGE precursory solutions mixed with either Ig2959 or LAP remained stable over time while the Ru/SPS system enabled the onset of controllable redox polymerization without irradiation during pre-incubation. Photo-polymerization using the Ru/SPS system was significantly faster (<5 s) compared to both Ig2959 (70 s) and LAP (50 s). Plus, The Ru/SPS system was capable of polymerizing a thick construct (8.88 ± 0.94 mm), while Ig2959 (1.62 ± 0.49 mm) initiated hydrogels displayed poor penetration depth with LAP (7.38 ± 2.13 mm) in between. These results thus support the use of the visible light based Ru/SPS photo-initiator for constructs requiring rapid gelation and a good curing depth while Ig2959 or LAP can be applied for photo-polymerization of GelAGE materials requiring long-term incubation prior to application if UV is not a concern.

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