scholarly journals ODEA: Orbital Dynamics in a complex Evolving Architecture

2019 ◽  
Vol 631 ◽  
pp. A139 ◽  
Author(s):  
L. Rodet ◽  
H. Beust ◽  
M. Bonnefoy ◽  
R. J. De Rosa ◽  
P. Kalas ◽  
...  
Keyword(s):  
Good Choice ◽  
Symplectic Integrators ◽  
Orbital Dynamics ◽  
System Type ◽  
Planetary Mass ◽  
Disk Plane ◽  
History Of ◽  
Solar Type ◽  
Debris Disk ◽  
Mixed Variable

Context. Mixed-variable symplectic integrators are widely used in orbital dynamics. However, they have been developed for Solar system-type architectures, and can not handle evolving hierarchy, in particular in systems with two or more stellar components. Such configuration may have occurred in the history of HD 106906, a tight pair of F-type stars surrounded by a debris disk and a planetary-mass companion on a wide orbit. Aims. We present the new algorithm ODEA, based on the symplectic algorithm Swift HJS, that can model any system (binary,...) with unstable architecture. We study the peculiar system HD 106906 as a testcase for the code. Methods. We define and compute a criterion based on acceleration ratios to indicate when the initial hierarchy is not relevant anymore. A new hierarchy is then computed. The code is applied to study the two recently evidenced fly-bys that occurred on system HD 106906, to determine if they could account for the wide orbit of the planet. Thousands of simulations have been performed to account for the uncertainty on the perturbers coordinates and velocities. Results. The algorithm is able to handle any change of hierarchy, temporary or not. We used it to fully model HD 106906 encounters. The simulations confirm that the fly-bys could have stabilized the planet orbit, and show that it can account for the planet probable misalignment with respect to the disk plane as well as the disk morphology. However, that requires a small distance at closest approach (≲0.05 pc), and this configuration is not guaranteed. Conclusions. ODEA is a very good choice for the study of non-Solar type architecture. It can now adapt to an evolving hierarchy, and is thus suitable to study capture of planets and dust. Further observations of the perturbers, in particular their radial velocity, are required to conclude on the effects of the fly-by on system HD 106906.

scholarly journals Infrared Absolute Calibration. I. Comparison of Sirius with Fainter Calibration Stars

2022 ◽  
Vol 163 (2) ◽  
pp. 45
Author(s):  
G. H. Rieke ◽  
Kate Su ◽  
G. C. Sloan ◽  
E. Schlawin
Keyword(s):  
Near Infrared ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Absolute Calibration ◽  
Absolute Flux ◽  
James Webb Space Telescope ◽  
Infrared Spectral ◽  
History Of ◽  
Flux Measurements ◽  
Debris Disk

Abstract A challenge in absolute calibration is to relate very bright stars with physical flux measurements to faint ones within range of modern instruments, e.g., those on large ground-based telescopes or the James Webb Space Telescope (JWST). We propose Sirius as the fiducial color standard. It is an A0V star that is slowly rotating and does not have infrared excesses due to either hot dust or a planetary debris disk; it also has a number of accurate (∼1%–2%) absolute flux measurements. We accurately transfer the near-infrared flux from Sirius to BD +60 1753, an unobscured early A-type star (A1V, V ≈ 9.6, E(B – V) ≈ 0.009) that is faint enough to serve as a primary absolute flux calibrator for JWST. Its near-infrared spectral energy distribution and that of Sirius should be virtually identical. We have determined its output relative to that of Sirius in a number of different ways, all of which give consistent results within ∼1%. We also transfer the calibration to GSPC P330-E, a well-calibrated close solar analog (G2V). We have emphasized the 2MASS K S band, since it represents a large number and long history of measurements, but the theoretical spectra (i.e., from CALSPEC) of these stars can be used to extend this result throughout the near- and mid-infrared.

Currently Functioning European Party Systems

2021 ◽  
pp. 52-82
Author(s):  
Fernando Casal Bértoa ◽  
Zsolt Enyedi
Keyword(s):  
Party System ◽  
Party Systems ◽  
Party Politics ◽  
System Type ◽  
History Of

This chapter presents the profile and the condensed history of the 41 currently functioning party systems. Here we discuss the dynamics of the changes, and relate them to the ideological configurations and alliance structures. We show that the changes in closure figures indicate well the transformations of party politics, we link developments in the governmental arena to the conflicts in the party system in general, and we associate each party system with a specific trajectory of closure development and a specific party system type. We show how the plurality of currently functioning party systems fit into a bipolar configuration that puts them on track towards a robust path of continuous stabilization until reaching full systemic institutionalization.

Cardiology

2018 ◽  
pp. 258-261
Author(s):  
Janey Phelps
Keyword(s):  
Transesophageal Echocardiography ◽  
Previous History ◽  
Pediatric Anesthesia ◽  
Invasive Procedure ◽  
Patient Characteristics ◽  
The United States ◽  
Good Choice ◽  
Risk Patients ◽  
History Of ◽  
Intranasal Midazolam

Congenital heart disease is the most common type of birth defect and is estimated to affect nearly 1% of all births per year in the United States. Echocardiograms are necessary to fully evaluate these defects, and depending on the age of the child, sedation may be required to ensure optimal imaging. This chapter discusses the sedation/anesthesia options for transthoracic echocardiography, transesophageal echocardiography, and cardioversion. For all of these procedures high-risk patients should be triaged to a pediatric anesthesia provider and in some cases, a pediatric cardiac anesthesiologist. Transthoracic echocardiograms can be completed with distraction and/or minimal sedation with oral or intranasal midazolam. If moderate sedation is required due to patient characteristics or previous history of failure with minimal sedation, intranasal dexmedetomidine is a good option. Transesophageal echocardiography is an invasive procedure; patients <2 years of age should be intubated and those >2 years of age can maintain a native airway with deep sedation with propofol. The need for cardioversion is infrequent in pediatrics but when needed, propofol is a good choice.

scholarly journals Experimental Methods in Agricultural and Resource Economics: How Useful are They?

1993 ◽  
Vol 22 (2) ◽  
pp. 103-116 ◽  
Author(s):  
Ann Fisher ◽  
William J. Wheeler ◽  
Rami Zwick
Keyword(s):  
Laboratory Experiment ◽  
Experimental Economics ◽  
Survey Data ◽  
Experimental Methods ◽  
Resource Economics ◽  
Good Choice ◽  
Experiment Data ◽  
Advantages And Disadvantages ◽  
History Of

Experimental economics has the potential to fill some of the gaps in the economist's tool kit. This article describes experimental economics, its advantages and disadvantages, and why this tool might be a good choice in some situations. The article summarizes the history of its use by agricultural and resource economists. An illustrative example compares laboratory experiment data with survey data.

scholarly journals Rapid Methods To Enumerate Escherichia coli in Foods Using 4-Methylumbelliferyl-ß-D-Glucuronide

2001 ◽  
Vol 84 (2) ◽  
pp. 407-415
Author(s):  
Diane F Ekholm ◽  
Irvin N Hirshfield
Keyword(s):  
Escherichia Coli ◽  
Cost Effective ◽  
Good Choice ◽  
Biochemical Tests ◽  
Rapid Methods ◽  
E Coli ◽  
Tree Nuts ◽  
Cost Effective Method ◽  
History Of ◽  
Hard Cheese

Abstract Three methods to enumerate Escherichia coli in food were compared. They were based on AOAC methods using lauryl tryptose broth (LST) medium, LST-4-methylumbelliferyl-ß-D-glucuronide (MUG) medium, and a proposed method using regular LST in combination with E. coli (EC)–MUG medium. An efficacious and cost-effective method is needed that can detect E. Coli and does not produce false presumptive positives. We tested 170 cheeses, 40 frozen processed seafood samples, 210 tree nuts, and 40 other samples. The method of choice for enumerating E. Coli depends on the commodity itself. For a product, such as hard cheese or processed seafood, with a history of being negative for E. Coli and other lactose-fermenting organisms, the proposed method using regular LST/EC–MUG is a good choice. These samples were seldom presumptive positive in the primary LST medium. If gas was produced, EC–MUG was an effective secondary medium. No false positives (fluorescence) or negatives were detected in EC–MUG medium. For a product with a history of being positive for E. Coli and/or other lactose fermenting organisms, such as tree nutmeats or cheeses that are ripened by bacteria or mold, the method using LST–MUG is the method of choice. A presumptive positive in the LST–MUG medium was highly correlative with the biochemical tests that confirmed a sample contain E. Coli. For samples spiked with E. Coli, the results from each of these 3 methods were identical, and were consistent in enumerating E. Coli.

scholarly journals Asymptomatic Crohn’s disease identified in a patient being treated with secukinumab: A case report

2019 ◽  
Vol 7 ◽  
pp. 2050313X1989358
Author(s):  
Wasim Haidari ◽  
Sarah Al-Naqshabandi ◽  
Christine S Ahn ◽  
Richard S Bloomfeld ◽  
Steven R Feldman
Keyword(s):  
Inflammatory Bowel Disease ◽  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Bowel Disease ◽  
Gastrointestinal Symptoms ◽  
Good Choice ◽  
History Of ◽  
Inflammatory Bowel ◽  
Multiple Ulcers ◽  
New Onset

IL-17 antagonism is among the most potent treatments for psoriasis. Generally safe, new onset and exacerbations of inflammatory bowel disease may occur in association with IL-17 therapy. We describe a patient with long-standing history of psoriasis and psoriatic arthritis in whom asymptomatic Crohn’s disease was identified during treatment with secukinumab. The patient underwent an elective colonoscopy for colorectal cancer screening which revealed inflammation and multiple ulcers in the terminal ileum suggestive of Crohn’s disease. While the patient did not have any gastrointestinal symptoms, he was diagnosed as having asymptomatic Crohn’s disease. Given the association of inflammatory bowel disease with secukinumab treatment, secukinumab was discontinued. Although in this patient, Crohn’s disease was identified during treatment with secukinumab, a direct causal relationship cannot be assumed. Medications that are effective for both psoriasis and inflammatory bowel disease may be a good choice in patients with psoriasis who have comorbid Crohn’s disease or develop inflammatory bowel disease during treatment with another biologic.

scholarly journals Beryllium in the Sun: Re-Measurement and Implications

2000 ◽  
Vol 198 ◽  
pp. 383-388
Author(s):  
Suchitra C. Balachandran
Keyword(s):  
Empirical Process ◽  
Convective Zone ◽  
The Sun ◽  
History Of ◽  
Solar Type ◽  
Entire History

The solar beryllium abundance is important because it provides a constraint on the depth to which mixing has occurred below the surface convective zone. Unlike helioseismology which only maps the present-day Sun, the solar beryllium abundance provides an integrated picture of mixing over the entire history of the Sun. In this review I outline the logic involving the ‘missing UV opacity’ that required that the solar beryllium abundance be re-determined. A brief summary of the empirical process of estimating the “missing UV opacity” is given along with a confirmation based on a recent re-calculation of the Fe I bound-free opacity. The addition of this opacity resulted in our finding that the solar beryllium abundance was meteoritic. The implications of this result in the context of mixing in solar-type stars is discussed.

Historical (i.e. Defunct) European Party Systems

2021 ◽  
pp. 86-105
Author(s):  
Fernando Casal Bértoa ◽  
Zsolt Enyedi
Keyword(s):  
Party System ◽  
Party Systems ◽  
Party Politics ◽  
System Type ◽  
History Of ◽  
High Level

The fourth chapter presents the profile and the condensed history of the 21 historical party systems that ceased to be democratic. Here we discuss the dynamics of the changes, and relate them to the ideological configurations and alliance structures. We show that the changes in closure figures indicate well the transformations of party politics, we link developments in the governmental arena to the conflicts in the party system in general, and we associate each party system with a specific trajectory of closure development and a specific party system type. We show how, in clear contrast to currently functioning European party systems, the plurality of historical party systems fit into a multi-polar configuration that impeded them from reaching higher levels of systemic stability. Tellingly, we find no instances of consistent growth and high-level stabilization or grand coalitions. Two-party and two-plus-one party systems, so common in currently functioning party systems, were also extremely rare among the collapsed systems.

scholarly journals Comprehensive Census and Complete Characterization of Nearby Debris Disk Stars

2015 ◽  
Vol 10 (S314) ◽  
pp. 179-182
Author(s):  
Tara H. Cotten ◽  
Inseok Song
Keyword(s):  
Large Scale ◽  
Complete Characterization ◽  
High Resolution Spectroscopy ◽  
Debris Disks ◽  
Infrared Excess ◽  
History Of ◽  
Debris Disk ◽  
Host Stars ◽  
Comprehensive Study

AbstractDebris disks are intimately linked to planetary system evolution since the rocky material surrounding the host stars is believed to be due to secondary generation from the collisions of planetesimals. With the conclusion and lack of future large scale infrared excess survey missions, it is time to summarize the history of using excess emission in the infrared as a tracer of debris and exploit all available data as well as provide a comprehensive study of the parameters of these important objects. We have compiled a catalog of infrared excess stars from peer-reviewed articles and performed an extensive search for new debris disks by cross-correlating the Tycho-2 and AllWISE catalogs. This study will conclude following the thorough examination of each debris disk star's parameters obtained through high-resolution spectroscopy at various facilities which is currently ongoing. We will maintain a webpage (www.debrisdisks.org) devoted to these infrared excess sources and provide various resources related to our catalog creation, SED fitting, and data reduction.

scholarly journals The Origin and Early History of the Sun and the Planetary System in the Context of Stellar Evolution

1983 ◽  
Vol 6 ◽  
pp. 15-28 ◽  
Author(s):  
G. H. Herbig
Keyword(s):  
Planetary System ◽  
Axial Rotation ◽  
Early History ◽  
The Sun ◽  
Primitive Earth ◽  
Stellar Astronomy ◽  
History Of ◽  
Solar Type ◽  
Fu Ori ◽  
Orion Trapezium

AbstractA plausible scenario for the early history of the sun can be constructed by combining the results of stellar astronomy with lunar and meteoritic chronologies. The meteorites apparently contain material exposed to two nucleosynthetic events, one about 108 yr and another a few 106 yr before solidification. Following II. Reeves, these are associated with supernovae occurring in star clusters in molecular clouds that formed during passage through successive galactic arm shocks. The Orion Trapezium Cluster may be a modern example; its density is such that encounters between members would have been close enough and frequent enough to have had major effects upon their circumstellar ‘solar nebulae,’ as would recurrent FU Ori-like eruptions of the stars themselves. The lunar bombardment continued for 7 × 108 yr following formation of our sun. If this represented disk cleanup, disks must persist for that long, and hence circumstellar activity may still be in progress around some young stars in the solar vicinity. The observed time decay of axial rotation and surface activity in solar-type stars can be extended backwards, and indicates that the ultraviolet radiation of the young sun would have had major photochemical consequences upon the primitive earth.

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