scholarly journals John Couch Adams: mathematical astronomer, college friend of George Gabriel Stokes and promotor of women in astronomy

2020 ◽  
Vol 378 (2179) ◽  
pp. 20190517
Author(s):  
Davor Krajnović
Keyword(s):  
Scientific Work ◽  
Meteor Shower ◽  
Good Friend ◽  
Lunar Theory ◽  
The Moon ◽  
Physical Explanation ◽  
Theme Issue ◽  
Change In The Mean ◽  
The Mean ◽  
Scientific Achievements

John Couch Adams predicted the location of Neptune in the sky, calculated the expectation of the change in the mean motion of the Moon due to the Earth’s pull, and determined the origin and the orbit of the Leonids meteor shower which had puzzled astronomers for almost a thousand years. With his achievements Adams can be compared with his good friend George Stokes. Not only were they born in the same year but were also both senior wranglers, received the Smith’s Prizes and Copley medals, lived, thought and researched at Pembroke College, and shared an appreciation of Newton. On the other hand, Adams’ prediction of Neptune’s location had absolutely no influence on its discovery in Berlin. His lunar theory did not offer a physical explanation for the Moon’s motion. The origin of the Leonids was explained by others before him. Adams refused a knighthood and an appointment as Astronomer Royal. He was reluctant and slow to publish, but loved to derive the values of logarithms to 263 decimal places. The maths and calculations at which he so excelled mark one of the high points of celestial mechanics, but are rarely taught nowadays in undergraduate courses. The differences and similarities between Adams and Stokes could not be more striking. This volume attests to the lasting legacy of Stokes’ scientific work. What is then Adams’ legacy? In this contribution, I will outline Adams’ life, instances when Stokes’ and Adams’ lives touched the most, his scientific achievements and a usually overlooked legacy: female higher education and support of a woman astronomer. This article is part of the theme issue ‘Stokes at 200 (part 2)’.

scholarly journals On the eclipses of agathocles, thales and xerxes

1854 ◽  
Vol 6 ◽  
pp. 277-281 ◽  
Keyword(s):  
Great Improvement ◽  
Lunar Theory ◽  
Progressive Change ◽  
Change In The Mean ◽  
The Mean ◽  
Made In

The author, after remarking that the calculations of distant eclipses made in the last century possess little value, proceeds to give the successive steps of improvement in the lunar theory as applicable to the computation of eclipses, and especially in the motion of the moon’s node. The first great improvement was the introduction by Laplace of terms expressing a progressive change in the mean secular motions. With Bürg’s tables, in which these changes were introduced, or with the same elements, Mr. Francis Baily and Mr. Ottmanns computed many eclipses in the search for that usually called the eclipse of Thales; and both these astronomers fixed upon the eclipse of b. c. 610, September 30, as the only one which could be reconciled with the account of Herodotus.

scholarly journals High Order Resonances in the Evolution of the Lunar Orbit

1983 ◽  
Vol 74 ◽  
pp. 3-17
Author(s):  
J. Kovalevsky
Keyword(s):  
Major Axis ◽  
Lunar Theory ◽  
The Moon ◽  
Tidal Effects ◽  
Semi Major Axis ◽  
Natural Satellite ◽  
Variation Of Constants ◽  
The Mean ◽  
Mean Elements

AbstractThis paper deals with the long term evolution of the motion of the Moon or any other natural satellite under the combined influence of gravitational forces (lunar theory) and the tidal effects. We study the equations that are left when all the periodic non-resonant terms are eliminated. They describe the evolution of the-mean elements of the Moon. Only the equations involving the variation of the semi-major axis are considered here. Simplified equations, preserving the Hamiltonian form of the lunar theory are first considered and solved. It is shown that librations exist only for those terms which have a coefficient in the lunar theory larger than a quantity A which is function of the magnitude of the tidal effects. The solution of the general case can be derived from a Hamiltonian solution by a method of variation of constants. The crossing of a libration region causes a retardation in the increase of the semi-major axis. These results are confirmed by numerical integration and orders of magnitude of this retardation are given.

XV. — Researches in physical astronomy

1831 ◽  
Vol 121 ◽  
pp. 231-282
Keyword(s):  
Differential Equations ◽  
The Other ◽  
Lunar Theory ◽  
System Of Equations ◽  
Planetary Theory ◽  
The Moon ◽  
Celestial Bodies ◽  
Independent Variable ◽  
The Mean ◽  
The One

The method pursued by Clairaut in the solution of this important problem of Physical Astronomy, consists in the integration of the differential equations furnished by the principles of dynamics, upon the hypothesis that in the gravitation of the celestial bodies the force varies inversely as the square of the distance, and in which the true longitude of the moon is the independent variable ; the time is thus obtained in terms of the true longitude, and by the reversion of series the longitude is afterwards obtained in terms of the time, which is necessary for the purpose of forming astronomical tables. But while on the one hand this method possesses the advantage, that the disturbing func­tion can be developed with somewhat greater facility in terms of the true lon­gitude of the moon than in terms of the mean longitude, yet on the other hand, the differential equations in which the true longitude is the independent variable are far more complicated than those in which the time is the inde­pendent variable. The latter equations are used in the planetary theory ; so that the method of Clairaut has the additional inconvenience, that while the lunar theory is a particular case of the problem of the three bodies, one system of equations is used in this case, and another in the case of the planets. The method of Clairaut has been adopted, however, by Mayer, by Laplace, and by M. Damoiseau. The last-mentioned author has arranged his results with remarkable clearness, so that any part of his processes may be easily verified by any one who does not shrink from this gigantic undertaking; and the immense labour which this method requires, when all sensible quantities are retained, may be seen in his invaluable memoir. Mr. Brice Bronwin has recently communicated to the Society a lunar theory, in which the same method is adopted.

The motion of a lunar orbiter

1966 ◽  
Vol 25 ◽  
pp. 373
Author(s):  
Y. Kozai
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Artificial Satellite ◽  
Equations Of Motion ◽  
Triaxial Ellipsoid ◽  
The Moon ◽  
Secular Motion ◽  
The Earth ◽  
Close Satellite ◽  
The Mean

The motion of an artificial satellite around the Moon is much more complicated than that around the Earth, since the shape of the Moon is a triaxial ellipsoid and the effect of the Earth on the motion is very important even for a very close satellite.The differential equations of motion of the satellite are written in canonical form of three degrees of freedom with time depending Hamiltonian. By eliminating short-periodic terms depending on the mean longitude of the satellite and by assuming that the Earth is moving on the lunar equator, however, the equations are reduced to those of two degrees of freedom with an energy integral.Since the mean motion of the Earth around the Moon is more rapid than the secular motion of the argument of pericentre of the satellite by a factor of one order, the terms depending on the longitude of the Earth can be eliminated, and the degree of freedom is reduced to one.Then the motion can be discussed by drawing equi-energy curves in two-dimensional space. According to these figures satellites with high inclination have large possibilities of falling down to the lunar surface even if the initial eccentricities are very small.The principal properties of the motion are not changed even if plausible values ofJ3andJ4of the Moon are included.This paper has been published in Publ. astr. Soc.Japan15, 301, 1963.

scholarly journals On tho proportions of the prevailing winds, the mean temperature, and depth of rain in the climate of London, computed through a cycle of Eighteen Years, or periods of the Moon’s declination

1843 ◽  
Vol 4 ◽  
pp. 300-300
Keyword(s):  
The Moon ◽  
Fair Weather ◽  
North West ◽  
West Wind ◽  
North East ◽  
East Wind ◽  
The North ◽  
The Common ◽  
The Mean ◽  
Solar Influence

In this paper the author investigates the periodical variations of the winds, rain and temperature, corresponding to the conditions of the moon’s declination, in a manner similar to that he has already followed in the case of the barometrical variations, on a period of years extending from 1815 to 1832 inclusive. In each case he gives tables of the average quantities for each week, at the middle of which the moon is in the equator, or else has either attained its maximum north or south declination. He thus finds that a north-east wind is most promoted by the constant solar influence which causes it, when the moon is about the equator, going from north to south; that a south-east wind, in like manner, prevails most when the moon is proceeding to acquire a southern declination ; that winds from the south and west blow more when the moon is in her mean degrees of declination, going either way, than with a full north or south declination ; and that a north-west wind, the common summer and fair weather wind of the climate, affects, in like manner, the mean declination, in either direction, in preference to the north or south, and most when the moon is coming north. He finds the average annual depth of rain, falling in the neighbourhood of London, is 25’17 inches.

Seven years follow-up of corneal cross-linking (CXL) in pediatric patients: Evaluation of treated and untreated eye

2021 ◽  
pp. 112067212110206
Author(s):  
Iliya Simantov ◽  
Lior Or ◽  
Inbal Gazit ◽  
Biana Dubinsky-Pertzov ◽  
David Zadok ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Pediatric Patients ◽  
Pediatric Population ◽  
Corneal Thickness ◽  
Cross Linking ◽  
Uncorrected Distance Visual Acuity ◽  
Mild Reduction ◽  
Change In The Mean ◽  
The Mean

Background: Retrospective cohort study evaluating long term keratoconus progression amongst cross-linking (CXL) treated pediatric patients in the treated and the fellow untreated eyes. Methods: Data on 60 eyes of 30 patients, 18 years old or younger, who underwent CXL in at least one eye was collected and analyzed. Follow-up measurements taken from the treated and untreated eye up to 7 years after CXL treatment, were compared to baseline measurements. Parameters included uncorrected distance visual acuity (UCDVA), best-corrected spectacle visual acuity (BCSVA), manifest refraction, pachymetry, corneal tomography, and topography. Results: Mean age of patients was 16 ± 2.1 years. For the treated eyes, during follow-up period mean UCDVA had improved (from 0.78 ± 0.22 at baseline to 0.58 ± 0.26 logMAR at 7 years; p = 0.13), as well as mean BCSVA (from 0.23 ± 0.107 at baseline to 0.172 ± 0.05 logMAR at 7 years; p = 0.37). The mean average keratometry showed a significant flattening (from 49.95 ± 4.04 to 47.94 ± 3.3 diopters (D); p < 0.001), However there was no change in the mean maximal keratometry. The mean minimal corneal thickness (MCT) showed a significant mild reduction of 26 µm ( p = 0.006). Although statistically insignificant, the mean manifest cylinder was also reduced to 2D ( p = 0.15). During the follow-up period, eight untreated eyes (26.6%) deteriorated and underwent CXL, while only one treated eye (3.33%) required an additional CXL. Conclusion: CXL is a safe and efficient procedure in halting keratoconus progression in the pediatric population, the fellow eye needs to be carefully monitored but only a 25% of the patients will require CXL in that eye during a period of 7 years.

Assessment and Bibliometric Review of Scientific Achievements Published in the Archives of Photogrammetry, Cartography and Remote Sensing

2019 ◽  
Vol 31 (1) ◽  
pp. 145-166
Author(s):  
Krzysztof Bakuła ◽  
Zdzisław Kurczyński
Keyword(s):  
Remote Sensing ◽  
Statistical Data ◽  
Spatial Information ◽  
Technological Development ◽  
Scientific Work ◽  
Scientific Institutions ◽  
Bibliometric Review ◽  
History Of ◽  
Gis Environment ◽  
Scientific Achievements

Abstract The Archives of Photogrammetry, Cartography and Remote Sensing is a journal which, in the era of technological development of photogrammetry and remote sensing and changes related to cartography in the field of common digitization of sources and processing of spatial information in GIS environment, has been one of the most popular places for publishing articles in this field in Poland for years. Thirty volumes published throughout 25 years have provided nearly 1000 scientific articles and monographic studies summarizing the scientific work of several hundred authors from dozens of scientific institutions and production companies in Poland. This article is an attempt to summarize the achievements published in the journal in the field of bibliometric evaluation and statistical data of the publications from the time of the existence of this inter-association journal. The text quotes the history of the journal, indicates statistics on the number of articles, their citation with the most popular items, authors, reviewers. This evaluation was compared with other national and foreign journals.

scholarly journals Personality development from 12 to 18 years of age: changes in mean levels and structure of traits

2004 ◽  
Vol 18 (6) ◽  
pp. 445-462 ◽  
Author(s):  
Jüri Allik ◽  
Kaia Laidra ◽  
Anu Realo ◽  
Helle Pullmann
Keyword(s):  
Personality Traits ◽  
Personality Development ◽  
The Self ◽  
Age Changes ◽  
Cross Sectional ◽  
Adult Personality ◽  
12Th Grade ◽  
Self Reports ◽  
Change In The Mean ◽  
The Mean

The Estonian NEO‐FFI was administered to 2650 Estonian adolescents (1420 girls and 1230 boys) aged from 12 to 18 years and attending 6th, 8th, 10th, or 12th grade at secondary schools all over Estonia. Although the mean levels of personality traits of Estonian adolescents were quite similar to the respective scores of Estonian adults, there was a developmental gap in Agreeableness and Conscientiousness. Three of the five personality dispositions demonstrated a modest cross‐sectional change in the mean level of the trait scores: the level of Openness increased and the levels of Agreeableness and Conscientiousness decreased between 12 and 18 years of age. Although the five‐factor structure of personality was already recognizable in the sample of 12‐year‐old children, it demonstrated only an approximate congruence with the adult structure, suggesting that not all children of that age have developed abilities required for observing one's own personality dispositions and for giving reliable self‐reports on the basis of these observations. The self‐reported personality trait structure matures and becomes sufficiently differentiated around age 14–15 and grows to be practically indistinguishable from adult personality by the age of 16. Personality of adolescents becomes more differentiated with age: along with the growth of mental capacities the correlations among the personality traits and intelligence become smaller. Copyright © 2004 John Wiley & Sons, Ltd.

scholarly journals Analysis of hydrological changes and flood increase in Niamey based on the PERSIANN-CDR satellite rainfall estimate and hydrological simulations over the 1983–2013 period

2015 ◽  
Vol 370 ◽  
pp. 117-123 ◽  
Author(s):  
C. Casse ◽  
M. Gosset
Keyword(s):  
Land Use Changes ◽  
Marked Change ◽  
Extreme Rainfall ◽  
Rapid Flow ◽  
Change In The Mean ◽  
The Mean ◽  
Satellite Rainfall ◽  
The City ◽  
Satellite Rainfall Estimate

Abstract. A dramatic increase in the frequency and intensity of floods due to the Niger River in the city of Niamey (Niger) has been observed in the last decade. Previous studies highlighted the role of the land use changes on the flood increase since 1970s. In the last decade, observations have raised the issue of a possible increase in extreme rainfall in the Sahel, which may have caused the recent and extreme floods in Niamey in 2010, 2012 and 2013. The study focuses on the 125 000 km2 basin between Ansongo and Niamey. This is the drainage area of the monsoon rainfall that leads to the rapid flow rise occurring between June and October. To understand the possible role of rainfall in flood intensification, satellite rainfall estimate is attractive in a region where the operational gauge network is sparse. This paper analyses the evolution of the Niger hydrograph in Niamey based on discharge observations, hydrological modelling and the satellite product PERSIANN-CDR, over the 1983–2013 period. PERSIANN-CDR is first compared with four other rainfall products. The salient features of the observed changes, i.e. a marked change in the mean decadal hydrograph, is well mimicked by the simulations, implying that rainfall is the first driver to the observed changes. The increase of flooded years over the period is also well reproduced but with some uncertainties in the exact number of flood days per year.

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