scholarly journals Area-Weighting of Sunspot Group Positions and Proper Motion Artifacts

1993 ◽  
Vol 141 ◽  
pp. 123-126
Author(s):  
K. Petrovay
Keyword(s):  
Proper Motion ◽  
Sunspot Group ◽  
Physical Nature ◽  
Decay Rates ◽  
Motion Artifacts ◽  
Point Of View ◽  
Theoretical Point ◽  
Analysis Process ◽  
The Mean ◽  
Sunspot Groups

AbstractTwo simple examples are presented to show that concepts about the physical nature of sunspot groups may significantly influence the statistical data analysis process. In particular, the second example shows that the well-known difference in the decay rates of preceding (p-) and following (f-) polarity parts of sunspot groups may lead to a fake proper motion effect when area-weighted group positions are used. This effect may be responsible for some recent contradictory findings concerning the motions of sunspot groups. It is therefore argued that while area-weighting is adequate when calculating the mean positions of p- and f-parts of a sunspot group separately, defining the position of the group as a whole by the unweighted average of the mean positions of the p- and f-parts is more satisfactory from the theoretical point of view (whenever it is possible to distinguish between spots of different polarities). Similarly, it is best not to “correct” sunspot proper motions for internal differential rotation within groups.

scholarly journals Competition Between Intramolecular Vibrational Energy Re-Distribution and Unimolecular Dissociation: A Scattering Theoretical Point of View

1995 ◽  
Vol 15 (2-4) ◽  
pp. 145-156 ◽  
Author(s):  
Kiyohiko Someda ◽  
Hiroki Nakamura ◽  
Frederick H. Mies
Keyword(s):  
Vibrational Energy ◽  
Stationary Wave ◽  
Resonance Scattering ◽  
Decay Rates ◽  
Point Of View ◽  
Unimolecular Dissociation ◽  
Theoretical Point ◽  
Mutual Correlation ◽  
Mean Width ◽  
The Mean

Systematic behavior of decay rates of resonances above dissociation threshold is investigated by using the theory of resonance scattering. The condition for the Rice-Ramsperger-Kassel-Marcus (RRKM) rate formula to be valid is clarified by analyzing the random model of unimolecular dissociation. The decay rate averaged over many resonances agrees with the RRKM rate when the mean spacing and the mean width of the resonance states coincide with each other. On the other hand, auto- and mutual-correlation functions of the non-stationary wave functions indicate a rather paradoxical and intriguing phenomenon: In the RRKM regime, insufficient time is left for intramolecular vibrational energy redistribution (IVR) before dissociation.

Sequential decisions in the control of a space-ship (finite fuel)

1967 ◽  
Vol 4 (3) ◽  
pp. 584-604 ◽  
Author(s):  
John Bather ◽  
Herman Chernoff
Keyword(s):  
Optimal Policy ◽  
Point Of View ◽  
Control Procedure ◽  
Theoretical Point ◽  
New Approach ◽  
Final Approach ◽  
The Mean ◽  
The Difference ◽  
Miss Distance ◽  
Quadratic Case

This paper is a sequel to [1] and considers a more realistic formulation of the same question: that of finding an optimal policy for controlling the path of a space-ship as it moves towards its target. The difference here is that we no longer suppose there is an infinite quantity of fuel, always available at a fixed price, for modifying the current direction of motion. This complicates the problem of reducing the final miss distance, by introducing an extra variable. As before, we shall be particularly concerned to find a control procedure which always minimizes the mean square terminal miss. From the theoretical point of view we are also interested to see whether the techniques used to approximate the optimal policy can be extended, and how far we shall be forced to adopt a new approach. Results are derived which provide bounds on the form of the optimal policy. The derivation depends on a comparison technique whose validity is intuitively obvious, but which is still only a conjecture. However, further confirmation is obtained in the quadratic case from asymptotic expansions giving the form of the solution both when the space-ship is far away from its target and during its final approach.

Development of Turbulence by the Interaction of Gas Flow with Plasmas

1973 ◽  
Vol 28 (8) ◽  
pp. 1281-1289 ◽  
Author(s):  
Lutz Niemeyer ◽  
Klaus Ragaller
Keyword(s):  
Gas Flow ◽  
Light Emission ◽  
Supersonic Nozzle ◽  
Physical Nature ◽  
Point Of View ◽  
Theoretical Point ◽  
High Current ◽  
Axial Pressure ◽  
Plasma Properties ◽  
Axial Pressure Gradient

A high current electric arc in the axis of a supersonic nozzle flow is studied experimentally and theoretically in order to clarify the physical nature of light emission fluctuations which are observed inside the nozzle. The gas flow is produced by discharging a high pressure reservoir of 20 at N2 through a nozzle of 12 mm throat diameter. The arc is fed with a rectangular current pulse of 1.9 kA amplitude and 5 ms duration. The light emission fluctuations of the arc are observed by photographic and photoelectric methods. The results of the observations are compared to theoretical estimates and lead to the conclusion that the fluctuations are caused by hydrodynamic turbulence. This turbulence is shown to be generated by the combined occurrence of a strong axial pressure gradient and a strong radial density gradient in the boundary layer between the arc and the surrounding cold gas flow. The influence of specific plasma properties on the character of the turbulence is briefly discussed from a theoretical point of view.

scholarly journals Durata e costo delle visite in medicina generale: il progetto DYSCO

2003 ◽  
Vol 4 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Livio Garattini ◽  
Emanuela Castelnuovo ◽  
Davide Lanzeni ◽  
Cecilia Viscarra ◽  
DYSCO VISITE Gruppo di studio DYSCO VISITE
Keyword(s):  
Methodological Approach ◽  
Point Of View ◽  
Theoretical Point ◽  
Ambulatory Visit ◽  
Real Cost ◽  
Number Of Patients ◽  
Travelling Time ◽  
The Mean ◽  
Number Of Visits ◽  
The Times

In Italy, general practitioners (GPs) operating within the National Health Service (NHS) are paid according to the number of patients followed, without relation to the number of visits performed. This means that, from a theoretical point of view, the marginal cost of an adjunctive medical examination equals to zero. Since this view is clearly little realistic, in this paper we expose a methodological approach to estimate the real cost of a GP visit, starting from data collected in the DYSCO study, a national survey on the medical costs of dystimia in Italy. 46 GPs were asked to record the number and duration of ambulatory and domiciliar visits, along with the time spent in administrative tasks, during 4 weeks, each randomly chosen within a season (spring, summer, autumn, winter). In order to assign a monetary value to each visit, the total fee reimbursed by the NHS to a GP was divided by the total time spent on work, and then again by the number of visits conducted during this time. The calculations performed revealed that the mean duration of a ambulatory visit amounts to about 10 minutes, while a domiciliar visit (including travelling time) lasts almost the double. An interesting result was that summer visits have significantly longer duration than the mean, and consequently cost more. The mean cost of a GP’s ambulatory visit resulted about 12 Euro; a domiciliar visit costs almost 23 Euro. The times and costs calculated in this study are consistent with other calculations performed by other authors in Europe and Italy, confirming the appropriateness of the employed methodology.

Sequential decisions in the control of a space-ship (finite fuel)

1967 ◽  
Vol 4 (03) ◽  
pp. 584-604 ◽  
Author(s):  
John Bather ◽  
Herman Chernoff
Keyword(s):  
Optimal Policy ◽  
Point Of View ◽  
Control Procedure ◽  
Theoretical Point ◽  
New Approach ◽  
Final Approach ◽  
The Mean ◽  
The Difference ◽  
Miss Distance ◽  
Quadratic Case

This paper is a sequel to [1] and considers a more realistic formulation of the same question: that of finding an optimal policy for controlling the path of a space-ship as it moves towards its target. The difference here is that we no longer suppose there is an infinite quantity of fuel, always available at a fixed price, for modifying the current direction of motion. This complicates the problem of reducing the final miss distance, by introducing an extra variable. As before, we shall be particularly concerned to find a control procedure which always minimizes the mean square terminal miss. From the theoretical point of view we are also interested to see whether the techniques used to approximate the optimal policy can be extended, and how far we shall be forced to adopt a new approach. Results are derived which provide bounds on the form of the optimal policy. The derivation depends on a comparison technique whose validity is intuitively obvious, but which is still only a conjecture. However, further confirmation is obtained in the quadratic case from asymptotic expansions giving the form of the solution both when the space-ship is far away from its target and during its final approach.

Generic Approach For Mathematical Model of Multi-Strain Pandemics

2021 ◽  
Author(s):  
Teddy Lazebnik ◽  
Svetlana Bunimovich-Mendrazitsky
Keyword(s):  
Mortality Rate ◽  
Basic Reproduction Number ◽  
Historical Data ◽  
Reproduction Number ◽  
Point Of View ◽  
World Health ◽  
Theoretical Point ◽  
Long Period ◽  
Proposed Model ◽  
The Mean

Pandemics with multi-strain have become a major concern. We introduce a new model for assessing the connection between multi-strain pandemic and the mortality rate, basic reproduction number, and the maximum of infected individuals. The proposed model provides a general mathematical approach for representing multi-strain pandemics, generalizing for an arbitrary number of strains. We show the proposed model fits well with epidemiological historical data world health over a long period. From a theoretical point of view, we show that the increasing number of strains increases logarithmically the maximum number of infected individuals and the mean mortality rate. Moreover, the mean basic reproduction number is statistically identical to the single, most aggressive strain pandemic for multi-strain pandemics.

URINARY EXCRETION OF INTERSTITIAL CELL STIMULATING HORMONE AND SPERM CONCENTRATION IN 219 MALES

1969 ◽  
Vol 62 (2) ◽  
pp. 299-305 ◽  
Author(s):  
Leif Wide ◽  
Berndt Kjessler
Keyword(s):  
Urinary Excretion ◽  
Replacement Therapy ◽  
Interstitial Cell ◽  
Sperm Concentration ◽  
Point Of View ◽  
Theoretical Point ◽  
Sperm Counts ◽  
Number Of Patients ◽  
The Mean ◽  
The Individual

ABSTRACT 219 male partners of barren marriages were examined with regard to urinary ICSH (LH) excretion and sperm concentration. The mean ICSH excretion in a group of patients with azoospermia was significantly higher as compared to a group of patients with more than 20 million sperms per ml. The individual excretion values were found to be widely distributed with a considerable overlapping between the groups. Only very few patients with low sperm counts had remarkably low ICSH excretion values. It appears as though only a very limited number of patients with impaired spermatogenesis would benefit from replacement therapy including gonadotrophins with ICSH activity; at least from a theoretical point of view.

Long-term variations in meridional motion of sunspot groups: comparison of DPD and SOON data

2018 ◽  
Vol 13 (S340) ◽  
pp. 51-52
Author(s):  
J. Javaraiah
Keyword(s):  
Solar Cycle ◽  
Sunspot Group ◽  
Group Data ◽  
Solar Cycle 23 ◽  
Meridional Motion ◽  
The Mean ◽  
Long Term Variations ◽  
Sunspot Groups

AbstractWe have analyzed the Debrecen Photoheliographic Data (DPD) and the Solar Optical Observing Network (SOON) sunspot group data during the period 1977 – 2015 and find that during the maximum of solar cycle 23 there is a large difference in the mean meridional motion of sunspot groups determined from DPD and SOON data.

Status of “AGK4” Project

1978 ◽  
Vol 48 ◽  
pp. 527-533
Author(s):  
Chr. de Vegt
Keyword(s):  
Northern Hemisphere ◽  
Proper Motion ◽  
The Mean ◽  
Spectral Bandpass

The present accuracy limit for the majority of fainter stars on the northern hemisphere is set by the AGK2/3-catalogue, recently completely finished, but it should be noted that its epoch is much earlier (1960). Furtheron the AGK3-catalogue is a direct repetition of the AGK2, the plates have been taken with the same astrograph in a broad blue spectral bandpass and measured visually with the same equipment, therefore virtually an instrumental standard of 1930 is realized again. Figure 1 shows the mean errors of the AGK2/3 catalogue positions as a function of magnitude. The best accuracy for the AGK2/3 data is obtained for the stars of about ninth magnitude: 017 (AGK2) and 020 (AGK3) but decreases for the faint stars with mpg11 to 019 (AGK2) and Pg 027 (AGK3). Here the AGK3 data are even less accurate. With increasing distance to the catalogue epochs, the accuracy of positions decreases due to the proper motion errors. In the upper part of figure 2 the dependence of the AGK2/3 catalogue accuracy on time is shown for the faint stars separately and an averaged value.

Timber Auctions in the Context of the Modern Auction Theory

2007 ◽  
pp. 86-94
Author(s):  
A. Manakov
Keyword(s):  
Theoretical Analysis ◽  
Auction Theory ◽  
Point Of View ◽  
Theoretical Point ◽  
English Auction ◽  
Analysis And Evaluation

The article provides theoretical analysis and evaluation of the timber auctions reforms in Russia. The author shows that the mechanism of the "combined auctions", which functioned until recently, is more appropriate from the theoretical point of view (and from the point of view of the Russian practice) as compared to the officially approved format of the English auction.

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