scholarly journals A Necessary Condition to the Simultaneous Correction of Celestial Reference Frames and Minor Planets Orbital Elements

1999 ◽  
Vol 172 ◽  
pp. 425-426
Author(s):  
M.J. Martínez Usó ◽  
F. Marco Castillo ◽  
J.A. López Ortí
Keyword(s):  
Reference Frame ◽  
Reference Frames ◽  
Geometrical Model ◽  
The Other ◽  
Necessary Condition ◽  
Minor Planets ◽  
Orbital Elements ◽  
Residual Function ◽  
Rotational Model ◽  
The Mean

AbstractIn order to obtain corrections to orbital elements of minor planets and to determine parameters of rotation of a reference frame, a geometrical model with restrictions in the declination, longitude of the ascending node and argument of the perihelion to minimize a residual function involving all named parameters was presented (Marco et al., 1996, 1997). On the other hand, such rotational model of correction should not modify the semiaxis, eccentricity nor the mean anomaly, so new restrictions on these parameters seem to be necessary. These conditions should reflect the invariability in the size of the orbit and they should be included in the model to complete a consistent set of restrictions.

Monetary and Financial Stability

2013 ◽  
Author(s):  
Brigitte Granville
Keyword(s):  
Financial Stability ◽  
The Other ◽  
Necessary Condition ◽  
Financial Instability ◽  
Information Flows ◽  
Asset Bubbles ◽  
Root Cause ◽  
Monetary Stability ◽  
Long Run ◽  
The Mean

This chapter examines the relation between monetary and financial stability, looking at possible chains of cause and effect running in both directions between them—from the possibility that an unexpected tightening of monetary policy increases the mean probability of financial system distress, to the general risk of monetary stability being undermined by financial instability. The idea that monetary stability encourages financial instability is controversial. Inflation is often the root cause of financial instability by distorting information flows between lenders and borrowers, leading to asset bubbles and over investment. Most empirical evidence tends to support the view that monetary stability should promote financial stability in the long run and not the other way around. But while monetary stability is a necessary condition for financial stability, it is not a sufficient one. In other words, financial instability can still occur even with the inflation rate under control.

Blind-Spots in Aristotle’s Doctrine of the Perceptual Mean

Apeiron ◽  
2020 ◽  
Vol 53 (3) ◽  
pp. 257-284
Author(s):  
Roberto Grasso
Keyword(s):  
Blind Spot ◽  
The Other ◽  
Final Part ◽  
Necessary Condition ◽  
Physiological Reaction ◽  
Sensory Apparatus ◽  
The Mean ◽  
Sense Of Touch ◽  
Blind Spots

AbstractThis paper aims to identify several interpretive problems posed by the final part of DA II.11 (423b27–424 a10), where Aristotle intertwines the thesis that a sense is like a ‘mean’ and an explanation for the existence of a ‘blind spot’ related to the sense of touch, adding the further contention that we are capable of discriminating because the mean ‘becomes the other opposite’ in relation to the perceptible property being perceived. To solve those problems, the paper explores a novel interpretation of Aristotle’s claims, arguing that they describe a homeostatic physiological reaction by which the sensory apparatus responds to perceptible stimuli. According to the proposed interpretation, such homeostatic reaction constitutes a necessary condition for perceiving what Aristotle refers to as ‘proper’ perceptible features, which include properties like ‘hot’ and ‘cold’ as well as colors and sounds.

Object-Centered Neglect in Patients with Unilateral Neglect: Effects of Left-Right Coordinates of Objects

1994 ◽  
Vol 6 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Marlene Behrmann ◽  
Morris Moscovitch
Keyword(s):  
Reference Frame ◽  
Reference Frames ◽  
Frame Of Reference ◽  
The Other ◽  
Unilateral Neglect ◽  
Independent Measure ◽  
Object Based ◽  
Spatial Coordinates ◽  
Left And Right

When patients with right-sided hemispheric lesions neglect information on the left side, with respect to what set of spatial coordinates is left defined? Two potential reference frames were examined in this study, one where left and right are defined with respect to the midline of the viewer and/or environment (viewer/env-centered) and the other where left and right are defined with respect to the midline of the object (object-centered). By rotating the stimulus 90° clockwise or counterclockwise, and instructing patients with neglect to report the colors appearing around the border of a stimulus, an independent measure was obtained for the number of colors reported from the left and right of the viewer/env- and from the object-based reference frame. Whereas significant object-centered neglect was observed only for upper case asymmetrical letters but not for symmetrical letters nor for drawings of familiar animals or objects, significant viewer/env-based neglect was observed with all the stimulus types. We present an account of the coexistence of neglect in more than one frame of reference and the presence of object-centered neglect under a restricted set of conditions.

scholarly journals Fundamental radio reference frame from VLA observations of minor planets

1988 ◽  
Vol 128 ◽  
pp. 97-97 ◽  
Author(s):  
G. H. Kaplan ◽  
K. J. Johnston ◽  
P. K. Seidelmann ◽  
C. M. Wade ◽  
T. S. Carroll
Keyword(s):  
Reference Frame ◽  
Reference Frames ◽  
Thermal Emission ◽  
Optical Observations ◽  
Minor Planets ◽  
Very Large Array ◽  
Test Particles ◽  
Optical Reference ◽  
Microwave Regime

The weak thermal emission from the largest minor planets can be detected in the microwave regime by the Very Large Array (VLA). Signal-to-noise ratios are sufficiently high to permit precise measurement of the positions of these objects at all points in their orbits with respect to background extragalactic sources. We are in the process of obtaining observations of astrometric accuracy for minor planets 1 Ceres, 2 Pallas, 4 Vesta, and 10 Hygeia.Minor planets have historically served as “test particles” in the solar system, and optical observations of these objects have been valuable in the determination of fundamental astronomical constants. In particular, optical observations of minor planets have played an important role in the establishment of the fundamental optical reference frame by permitting the determination of the orientation of the Earth's orbit relative to the stars defining the frame.Similarly, radio observations of these bodies can play a corresponding role in the establishment of a fundamental radio reference frame. Our observations will provide a direct link between the dynamical and radio reference frames, and provide important information on the relationship between the radio and optical reference frames.

Reliability of the Crossed-Hands Deficit in Tactile Temporal Order Judgements

2020 ◽  
pp. 1-35
Author(s):  
Kaian Unwalla ◽  
Hannah Kearney ◽  
David I. Shore
Keyword(s):  
Individual Differences ◽  
Reference Frame ◽  
Reference Frames ◽  
Temporal Order ◽  
High Reliability ◽  
Stimulus Location ◽  
The Other ◽  
Good Reliability ◽  
External Reference ◽  
Temporal Order Judgement

Abstract Crossing the hands over the midline impairs performance on a tactile temporal order judgement (TOJ) task, resulting in the crossed-hands deficit. This deficit results from a conflict between two reference frames — one internal (somatotopic) and the other external (spatial) — for coding stimulus location. The substantial individual differences observed in the crossed-hands deficit highlight the differential reliance on these reference frames. For example, women have been reported to place a greater emphasis on the external reference frame than men, resulting in a larger crossed-hands deficit for women. It has also been speculated that individuals with an eating disorder place a greater weight on the external reference frame. Further exploration of individual differences in reference frame weighing using a tactile TOJ task requires that the reliability of the task be established. In Experiment 1, we investigated the reliability of the tactile TOJ task across two sessions separated by one week and found high reliability in the magnitude of the crossed-hands deficit. In Experiment 2, we report the split-half reliability across multiple experiments (both published and unpublished). Overall, tactile TOJ reliability was high. Experiments with small to moderate crossed-hands deficits showed good reliability; those with larger deficits showed even higher reliability. Researchers should try to maximize the size of the effect when interested in individual differences in the use of the internal and external reference frames.

scholarly journals The use of the empirical mode decomposition for the identification of mean field aligned reference frames

2017 ◽  
Vol 59 (6) ◽  
Author(s):  
Mauro Regi ◽  
Alfredo Del Corpo ◽  
Marcello De Lauretis
Keyword(s):  
Magnetic Field ◽  
Reference Frame ◽  
Empirical Mode Decomposition ◽  
Reference Frames ◽  
Moving Average ◽  
Mean Field ◽  
Magnetized Plasma ◽  
Mode Decomposition ◽  
The Mean ◽  
The Magnetic Field

<p>The magnetic field satellite data are usually referred to geocentric coordinate reference frame. Conversely, the magnetohydrodynamic waves modes in magnetized plasma depend on the ambient magnetic field, and is then useful to rotate the magnetic field measurements into the mean field aligned (MFA) coordinate system. This reference frame is useful to study the ultra low frequency magnetic field variations along the direction of the mean field and perpendicularly to it. In order to identify the mean magnetic field the classical moving average (MAVG) approach is usually adopted but, under particular conditions, this procedure induces undesired features, such as spectral alteration in the rotated components. We discuss these aspects promoting an alternative and more efficient method for mean field aligned projection, based on the empirical mode decomposition (EMD).</p>

On nearly-commensurable periods in the restricted problem of three bodies, with calculations of the long-period variations in the interior 2:1 case

1966 ◽  
Vol 25 ◽  
pp. 197-222 ◽  
Author(s):  
P. J. Message
Keyword(s):  
Periodic Solution ◽  
Periodic Solutions ◽  
Large Amplitude ◽  
Restricted Problem ◽  
Small Amplitude ◽  
Minor Planets ◽  
Long Period ◽  
Numerical Integrations ◽  
Period Variations ◽  
The Mean

An analytical discussion of that case of motion in the restricted problem, in which the mean motions of the infinitesimal, and smaller-massed, bodies about the larger one are nearly in the ratio of two small integers displays the existence of a series of periodic solutions which, for commensurabilities of the typep+ 1:p, includes solutions of Poincaré'sdeuxième sortewhen the commensurability is very close, and of thepremière sortewhen it is less close. A linear treatment of the long-period variations of the elements, valid for motions in which the elements remain close to a particular periodic solution of this type, shows the continuity of near-commensurable motion with other motion, and some of the properties of long-period librations of small amplitude.To extend the investigation to other types of motion near commensurability, numerical integrations of the equations for the long-period variations of the elements were carried out for the 2:1 interior case (of which the planet 108 “Hecuba” is an example) to survey those motions in which the eccentricity takes values less than 0·1. An investigation of the effect of the large amplitude perturbations near commensurability on a distribution of minor planets, which is originally uniform over mean motion, shows a “draining off” effect from the vicinity of exact commensurability of a magnitude large enough to account for the observed gap in the distribution at the 2:1 commensurability.

Multi-Center Study of Thromboplastin Calibration Precision – Influence of Reagent Species, Composition, and International Sensitivity Index (ISI)

1993 ◽  
Vol 69 (01) ◽  
pp. 035-040 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina
Keyword(s):  
Oral Anticoagulants ◽  
International Normalized Ratio ◽  
The Other ◽  
World Health ◽  
Rabbit Brain ◽  
Sensitivity Index ◽  
Bovine Plasma ◽  
Significant Difference ◽  
The Mean ◽  
International Sensitivity Index

SummaryFour thromboplastin reagents were tested by 18 laboratories in Europe, North-America, and Australasia, according to a detailed protocol. One thromboplastin was the International Reference Preparation for ox brain thromboplastin combined with adsorbed bovine plasma (coded OBT/79), and the second was a certified reference material for rabbit brain thromboplastin, plain (coded CRM 149R). The other two thromboplastin reagents were another rabbit plain brain thromboplastin (RP) with a lower ISI than CRM 149R and a rabbit brain thromboplastin combined with adsorbed bovine plasma (RC). Calibration of the latter two reagents was performed according to methods recommended by the World Health Organization (W. H. O.).The purpose of this study was to answer the following questions: 1) Is the calibration of the RC reagent more precise against the bovine/combined (OBT/79) than against the rabbit/plain reagent (CRM 149R)? 2) Is the precision of calibration influenced by the magnitude of the International Sensitivity Index (ISI)?The lowest inter-laboratory variation of ISI was observed in the calibration of the rabbit/plain reagent (RP) against the other rabbit/plain reagent (CRM 149R) (CV 1.6%). The highest interlaboratory variation was obtained in the calibration of rabbit/plain (RP) against bovine/combined (OBT/79) (CV 5.1%). In the calibration of the rabbit/combined (RC) reagent, there was no difference in precision between OBT/79 (CV 4.3%) and CRM 149R (CV 4.2%). Furthermore, there was no significant difference in the precision of the ISI of RC obtained with CRM 149R (ISI = 1.343) and the rabbit/plain (RP) reagent with ISI = 1.14. In conclusion, the calibration of RC could be performed with similar precision with either OBT/79 or CRM 149R, or RP.The mean ISI values calculated with OBT/79 and CRM 149R were practically identical, indicating that there is no bias in the ISI of these reference preparations and that these reference preparations have been stable since their original calibration studies in 1979 and 1987, respectively.International Normalized Ratio (INR) equivalents were calculated for a lyophilized control plasma derived from patients treated with oral anticoagulants. There were small but significant differences in the mean INR equivalents between the bovine and rabbit thromboplastins. There were no differences in the interlaboratory variation of the INR equivalents, when the four thromboplastins were compared.

Prothrombin Time Standardization: Report of the Expert Panel on Oral Anticoagulant Control

1979 ◽  
Vol 42 (04) ◽  
pp. 1073-1114 ◽  
Keyword(s):  
Prothrombin Time ◽  
Expert Panel ◽  
The Other ◽  
Rabbit Brain ◽  
Calibration Constant ◽  
Freeze Dried ◽  
The Mean ◽  
Point Of Intersection ◽  
And Control ◽  
Standardization Report

SummaryIn collaborative experiments in 199 laboratories, nine commercial thromboplastins, four thromboplastins held by the National Institute for Biological Standards and Control (NIBS & C), London and the British Comparative Thromboplastin were tested on fresh normal and coumarin plasmas, and on three series of freeze-dried plasmas. One of these was made from coumarin plasmas and the other two were prepared from normal plasmas; in each series, one plasma was normal and the other two represented different degrees of coumarin defect.Each thromboplastin was calibrated against NIBS&C rabbit brain 70/178, from the slope of the line joining the origin to the point of intersection of the mean ratios of coumarin/normal prothrombin times when the ratios obtained with the two thromboplastins on the same fresh plasmas were plotted against each other. From previous evidence, the slopes were calculated which would have been obtained against the NIBS&C “research standard” thromboplastin 67/40, and termed the “calibration constant” of each thromboplastin. Values obtained from the freeze-dried coumarin plasmas gave generally similar results to those from fresh plasmas for all thromboplastins, whereas values from the artificial plasmas agreed with those from fresh plasmas only when similar thromboplastins were being compared.Taking into account the slopes of the calibration lines and the variation between laboratories, precision in obtaining a patient’s prothrombin time was similar for all thromboplastins.

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