scholarly journals Waves and tides in the atmosphere

1929 ◽  
Vol 126 (800) ◽  
pp. 169-183 ◽  
Keyword(s):  
Pressure Wave ◽  
Daily Variation ◽  
Barometric Pressure ◽  
Tidal Force ◽  
Periodic Oscillations ◽  
Tidal Forces ◽  
Waves And Tides ◽  
The Subject ◽  
Diurnal Effect ◽  
Chief Interest

Since the time of Laplace the periodic oscillations of the atmosphere as a whole have formed a constant subject for dynamical research. The chief interest has centred round the semidiurnal oscillation indicated by the great regularity of the semidiurnal component of the daily variation in barometric pressure. If the semidiurnal oscillation is due to gravitational tides it is very much greater than we should expect unless the tidal force is greatly enhanced by resonance. If it is due to the daily variation in temperature then should expect the diurnal effect to be greater than the semidiurnal unless the semidiurnal oscillation were greatly enhanced by resonance. Both these hypotheses involve the existence of a free period which differs from 12 hours by not more than 4 minutes. The inherent improbability that the appropriate mode of oscillation should chance to have a period so near to 12 hours caused Dr. H. Lamb to reject the tidal explanation of the semidiurnal pressure wave, but, as Prof. Chapman has pointed out in his very complete exposition of the subject, the “temperature variation” explanation requires resonance just as much as the “tidal” one. In fact Prof. Chapman attributes roughly half the effect to tidal forces and half to the daily variation in temperature.

A Romano-British Interment, with Bucket and Sceptres, from Brough, East Yorkshire

1938 ◽  
Vol 18 (1) ◽  
pp. 68-74 ◽  
Author(s):  
Philip Corder ◽  
I. A. Richmond
Keyword(s):  
Present Note ◽  
Fourth Century ◽  
The Other ◽  
The West ◽  
West Side ◽  
The Road ◽  
The Subject ◽  
Chief Interest ◽  
Roman Age ◽  
The Way

The Roman Ermine Street, having crossed the Humber on the way to York from Lincoln, leaves Brough Haven on its west side, and the little town of Petuaria to the east. For the first half-mile northwards from the Haven its course is not certainly known: then, followed by the modern road, it runs northwards through South Cave towards Market Weighton. In the area thus traversed by the Roman road burials of the Roman age have already been noted in sufficient quantity to suggest an extensive cemetery. The interment which is the subject of the present note was found on 10th October 1936, when men laying pipes at right angles to the modern road, in the carriage-drive of Mr. J. G. Southam, having cut through some 4 ft. of blown sand, came upon a mass of mixed Roman pottery, dating from the late first to the fourth century A.D. Bones of pig, dog, sheep, and ox were also represented. Presently, at a depth of about 5 ft., something attracted closer attention. A layer of thin limestone slabs was found, covering two human skeletons, one lying a few feet from the west margin of the modern road, the other parallel with the road and some 8 ft. from its edge. The objects described below were found with the second skeleton, and the first to be discovered was submitted by Mr. Southam to Mr. T. Sheppard, F.S.A.Scot., Director of the Hull Museums, who visited the site with his staff. All that can be recorded of the circumstances of the discovery is contained in the observations then made, under difficult conditions. ‘Slabs of hard limestone’, it was reported, ‘taken from a local quarry of millepore oolite and forming the original Roman road, were distinctly visible beneath the present roadway—one of the few points where the precise site of the old road has been located. On the side of this… a burial-place has been constructed. What it was like originally it is difficult to say, beyond that a layer of thin … slabs of limestone occurred over the skeletons. This had probably been kept in place or supported by some structure of wood, as several large iron nails, some bent at right angles, were among the bones.’ If this were all that could be said about the burials, they would hardly merit a place in these pages. The chief interest of the record would be its apparent identification of the exact course of the Roman road at a point where this had hitherto been uncertain. Three objects associated with the second skeleton are, however, of exceptional interest.

XX.—On a See-Saw of Barometric Pressure, Temperature, and Wind Velocity between the Weddell Sea and the Ross Sea

1915 ◽  
Vol 35 ◽  
pp. 203-216
Author(s):  
R. C. Mossman
Keyword(s):  
South America ◽  
Wind Velocity ◽  
Air Temperature ◽  
Ross Sea ◽  
Barometric Pressure ◽  
Meteorological Conditions ◽  
Weddell Sea ◽  
The Other ◽  
The Subject ◽  
The One

In the course of a large inquiry on the inter-relations between the meteorological conditions in Antarctica and the Southern Ocean, on the one hand, and those prevailing in the southern continents, more especially South America, on the other, there has come to light an interesting see-saw between the barometric pressure, air temperature, and wind velocity in the Weddell and the Boss Seas. The above inquiry, which I hope to lay before this Society shortly, refers to the eight-year period 1902–09; and since the present paper deals with the years 1902, 1903, 1911, and 1912, I have thought it better to make it the subject of a separate communication. The positions of these stations and others where observations have been made are shown on the accompanying map, for which I am indebted to Dr H. R. Mill. The figures within the rings give the number of years covered by the records at the various places.

Effects of nitroglycerin on liquid gastric emptying and antropyloroduodenal motility

1998 ◽  
Vol 275 (5) ◽  
pp. G1173-G1178 ◽  
Author(s):  
W.-M. Sun ◽  
S. Doran ◽  
K. L. Jones ◽  
E. Ooi ◽  
G. Boeckxstaens ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Gastric Emptying ◽  
Pressure Wave ◽  
Normal Subjects ◽  
Nitric Oxide Donor ◽  
Pressure Waves ◽  
The Subject ◽  
And Control ◽  
Male Subjects

The effects of the nitric oxide donor nitroglycerin on gastric emptying and antropyloroduodenal motility were evaluated in nine healthy male subjects (ages 19–36 yr). Antropyloroduodenal pressures were recorded with a manometric assembly that had nine side holes spanning the antrum and proximal duodenum and a pyloric sleeve sensor; gastric emptying was quantified scintigraphically. In each subject, the emptying of 300 ml of 25% glucose labeled with99mTc was assessed on two separate days during intravenous infusion of either nitroglycerin (5 μg/min in 5% dextrose) or 5% dextrose (control). Studies were performed with the subject in the supine position; blood pressure and heart rate were monitored. Nitroglycerin had no significant effect on blood pressure or heart rate. Nitroglycerin slowed gastric emptying ( P < 0.02), and this was associated with greater retention of the drink in the proximal stomach ( P < 0.05). In both nitroglycerin and control studies, ingestion of the drink was associated with an increase in the number of isolated pyloric pressure waves ( P < 0.05) and antral pressure wave sequences ( P < 0.05). Nitroglycerin reduced the number of isolated pyloric pressure waves ( P < 0.05), basal pyloric pressure ( P < 0.05), and the number of antral pressure wave sequences ( P < 0.05), but not the total number of antral pressure waves. The rate of gastric emptying and the number of isolated pyloric pressure waves were inversely related during control ( P = 0.03) and nitroglycerin ( P < 0.05) infusions. We conclude that in normal subjects, 1) gastric emptying of 300 ml of 25% glucose is inversely related to the frequency of phasic pyloric pressure waves, and 2) nitroglycerin in a dose of 5 μg/min inhibits pyloric motility, alters the organization but not the number of antral pressure waves, and slows gastric emptying and intragastric distribution of 25% glucose.

On the Overlap of the Upper Gault in England and on the “Red Chalk” of the Eastern Counties

1922 ◽  
Vol 59 (4) ◽  
pp. 156-166 ◽  
Author(s):  
F. L. Kitchin ◽  
J. Pringle
Keyword(s):  
North East ◽  
The North ◽  
Inverted Order ◽  
The Subject ◽  
The Difference ◽  
Chief Interest

During the years 1918–19 we investigated the relations of the beds exposed in a remarkable section at Shenley Hill, north of Leighton Buzzard. Our conclusion that lenticles of limestone of basal varians-age are there overlain by a mass of Upper Gault showing an inverted order of zones provided an interesting glacial problem. This seemed to us of less importance, however, than the discovery that these transported masses had been deposited upon a, floor formed by a basement-bed of transgressive Upper Gault, which there rests immediately upon the local top of the Lower Greensand. The chief interest attaching to this example of glacial disturbance lay in the resulting disposition of particular beds in anomalous zonal relationships. Other striking instances of the glacial transportation of large masses of rock were known to occur in the tract of country to the north-east of this locality. The difference was chiefly one of degree, not of kind. We realized that the detection here of an overlap of the Upper Gault might prove to be a matter of greater moment, possessing, perhaps, a far-reaching stratigraphical significance. A study of the literature dealing with this formation, coupled with the examination of the Gault at a few localities in other counties where an overlap takes place, convinced us that a fuller investigation of the subject would prove fruitful in results.

scholarly journals Croonian lecture : The respiratory process in muscle and the nature of muscular motion

1917 ◽  
Vol 89 (619) ◽  
pp. 444-467 ◽  
Keyword(s):  
Animal Cell ◽  
Chemical Processes ◽  
Specific Chemical ◽  
Cell Life ◽  
History Of ◽  
Living Substance ◽  
Intimate Knowledge ◽  
The Subject ◽  
To Come ◽  
Chief Interest

Mr. President and Fellows: —We are keenly sensible of the honour done to us in our being called to lecture on this occasion, and in making this acknowledgment we would express our special gratification in being so enabled to pay this act of piety to the memory of William Croone, whom we commemorate to-day. The Croonian Lecture was founded through his generosity in order to encourage the study of muscular motion, but some sixteen years have now passed since that subject was last treated by the Lecturer. During those years many additions have been made to our knowledge of the subject, and great changes have resulted in our views of it. It is a pleasure to us that we have now the opportunity of taking up again the broken thread of the series, and of turning to-day to the chosen subject of Croone’s own enquiries and chief interest. We could wish that a time more free from other occupations and anxieties than the present had allowed us to do this less unworthily. Croone found in muscle the chief immediate hope of studying the energy discharges of living elements, and it was surely an enlightened instinct which led him to foresee, however dimly then, what we must recognise as still true after this lapse of two and a half centuries. We still must look to the study of muscular motion as the most fruitful, and perhaps for some time to come the only, avenue to intimate' knowledge of the modes of energy discharge by the living cell, and of their relation to the specific chemical processes of life. More than this, it is the study of muscle activity which has so far given us all we know of the meaning of respiration as the accompaniment of life. The study of respiratory exchanges in the lungs and in the blood of mammals has given us valuable lessons, and has unfolded attractive stories of animal adaptation to environment. That study takes its place in the natural history of the Vertebrates, and has a living value for the purposes of human medicine. It is describing to us the modes in which oxygen reaches and carbon dioxide leaves the cell under the anatomical conditions of the vertebrate animal, but it does not attack the intimate problems of respiration as a process of animal cell life in general. Croone, of Cambridge, was too close in time and sympathy to the genius of Mayow, and to the work of his other contemporaries at Oxford, not to realise that in the study of muscle lay probably the first path to knowledge of the inner processes of life within the living substance itself.

A plethysmograph for long-term measurements of ventilation in unrestrained animals

1978 ◽  
Vol 45 (4) ◽  
pp. 644-647 ◽  
Author(s):  
J. P. Jacky
Keyword(s):  
Quantitative Measurement ◽  
Electronic Device ◽  
Respiratory Control ◽  
Barometric Pressure ◽  
High Flow ◽  
Small Animals ◽  
Pressure Oscillations ◽  
The Subject ◽  
Long Term Measurement

An apparatus for quantitative measurement of ventilation in unrestrained small animals is described. The subject rests in an environmental chamber, and respiration is indicated by barometric pressure oscillations proportional to tidal volume. The chamber is purged continuously at a relatively high flow rate during studies. Thus, CO2 does not accumulate and long-term measurement can proceed without interruption. Respiratory control studies are especially facilitated since different gas mixtures can be rapidly passed through the chamber. An electronic device also is described which automatically calculates expired minute volumes (VE) from the pressure signal obtained from the plethysmograph.

scholarly journals The harder they fall, the bigger they become: tidal trapping of strings by microstate geometries

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Emil J. Martinec ◽  
Nicholas P. Warner
Keyword(s):  
Kinetic Energy ◽  
Transit Time ◽  
Incident Energy ◽  
Tidal Force ◽  
Massive String ◽  
Tidal Forces

Abstract We consider the fate of a massless (or ultra-relativistic massive) string probe propagating down the BTZ-like throat of a microstate geometry in the D1-D5 system. Far down the throat, the probe encounters large tidal forces that stretch and excite the string. The excitations are limited by the very short transit time through the region of large tidal force, leading to a controlled approximation to tidal stretching. We show that the amount of stretching is proportional to the incident energy, and that it robs the probe of the kinetic energy it would need to travel back up the throat. As a consequence, the probe is effectively trapped far down the throat and, through repeated return passes, scrambles into the ensemble of nearby microstates. We propose that this tidal trapping may lead to weak gravitational echoes.

scholarly journals Tidal forces in Kottler spacetimes

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
V. P. Vandeev ◽  
A. N. Semenova
Keyword(s):  
Black Hole ◽  
Cosmological Constant ◽  
Radial Component ◽  
Tidal Force ◽  
De Sitter ◽  
Geodesic Deviation ◽  
Tidal Forces ◽  
Sitter Spacetime ◽  
Deviation Equation ◽  
Deviation Vector

AbstractThe article considers tidal forces in the vicinity of the Kottler black hole. We find a solution of the geodesic deviation equation for radially falling bodies, which is determined by elliptic integrals. And also the asymptotic behavior of all spatial geodesic deviation vector components were found. We demonstrate that the radial component of the tidal force changes sign outside the single event horizon for any negative values of the cosmological constant, in contrast to the Schwarzschild black hole, where all the components of the tidal force are sign-constant. We also find the similarity between the Kottler black hole and the Reissner–Nordström black hole, because we indicate the value of the cosmological constant, which ensures the existence of two horizons of the black hole, between which the angular components of the tidal force change sign. It was possible to detect non-analytical behavior of geodesic deviation vector components in anti-de Sitter spacetime and to describe it locally.

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