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USING double-barrelled micro-electrodes, one barrel for recording the other for passing current, it has been found possible to observe the effects of hyper -and de-polarizing currents on the membrane behaviour of actively beating heart muscle.

These experiments were undertaken with the view of ascertaining whether the action of steam upon the hull of an iron vessel affects a compass, properly placed, in any degree that may be of practical importance in its navigation; and also whether the keeling of the vessel produces any alteration in the deviations, or disturbs a compass so placed to any considerable extent. The former question is, from the results of these experiments, resolved in the negative; but with respect to the second, it appears that the deviations produced by keeling are very marked, and could not be safely disregarded. These observations completely confirm those already made by Mr. Walker and Commander Shaugh on board H. M. Iron Brig 'Recruit,’ Commander A. Slade, and they prove the necessity that exists for ascertaining the deviations of the compass in all ships, not only at the beginning and end of their voyage, but likewise at intermediate stations; as also constant observation of the course which the ship may be steering.

Briscoe and Burn1 have shown that acetylcholine will restore the spontaneous contractions of rabbit atria which have been arrested by quinidine. Armitage2 has suggested that quinidine impairs repolarization by rendering the cell membrane less permeable to potassium ions, and acetylcholine restarts the tissue by restoring the potassium permeability. However, Weidmann3, Johnson4 and Johnson and McKinnon5 have demonstrated that in cardiac muscle quinidine predominantly affected the depolarization phase of the action potential. The maximum rate of rise of the action potential was grossly decreased with little or no concomitant change in the membrane resting potential, indicating that the drug had a direct effect on the sodium-carrying system.

The article presents a dissertation abstract titled “A Comparative Study of Selected Problem Areas in the Administration of the Personnel Function in Small and Large Firms,” by Edward Alden Johnson.

In a recent paper (Jansons & Johnson 1988) the authors discuss topographic Rossby waves over a random array of seamounts. It is noted that resonance is possible between a hill and an equal and opposite dale but such resonances are mentioned only briefly due to the small likelihood of correctly matched topography in the ocean. The present paper considers the resonances in detail showing how the normal modes formed by frequency splitting at resonance can be combined to give modes that slowly transfer energy from one region supporting topographic waves, across a region where such weaves are evanescent, to another region supporting waves. In addition to the simplest case of a hill—dale pair for which an exact energy-transferring mode is obtained, transferring modes are given for a three-hill system, for two hills near a coastal boundary, and for two-basin lakes. The analysis is simplified and the results generalized by extensive use of the invariance of the governing equation under conformal mappings. A transferring mode is given for a dale in a random array of seamounts showing energy leaking slowly from the dale to large distances and returning, with the rate of leakage depending on the area fraction of seamounts. It is concluded that although resonances and transferring modes are not likely to be important in random arrays on infinite planes, they are relevant to numerical models, which are necessarily restricted to finite domains, to coastal seamount chains, and to multi-basin lakes.

The initial-value problem for Taylor columns is considered for the oceanographically relevant case of slow flow over obstacles of small slope, and horizontal scale of order of the fluid depth or larger. In such flows depth variations cause, in the neighbourhood of the obstacle, a gradient of background potential vorticity. Topographic Rossby waves, forced in the starting flow, propagate across the gradient, cycling the obstacle in times of order of the topographic vortex-stretching time h /2Ω h 0 , where h is the fluid depth, Ω the background rotation rate and h 0 the obstacle height. The linear inertialwave equation and the quasigeostrophic equations are related by considering the case where the inertial period is small compared with the topographic time, which is in turn small compared with the advection time. When viscosity is present the waves decay to a steady motion in a time of order of the viscous spin-up time. In inviscid flow the waves do not decay. The flow oscillates about steady, irrotational, zero-circulation flow. The drag and lift on the obstacle oscillate with almost constant frequency and amplitude equal to the Coriolis force on a body of fluid whose volume matches that of the obstacle. Particles above a right cylinder move in closed orbits of diameter 1/ S , where S is the topographic parameter introduced by Hide (1961). Particles away from the cylinder move irrotationally, but asymmetrically, from upstream to downstream. A shear layer is present at the boundary of the cylinder throughout the motion. The initial vorticity distribution for flow over a paraboloid is everywhere finite. However, regions of positive and negative vorticity interlace ever more closely during the motion, causing at large time a similar shear layer at the column boundary. By this time the vorticity is increasing without bound above the obstacle and neglected nonlinear, horizontal viscous, or vertical effects are important.

Catecholamines (isoproterenol, norepinephrine, methoxamine) have an effect on the force-interval relationship (FIR) (the way the force of contraction depends on the rate and pattern of stimulation) which is unique among inotropic agents. Although the effect on the FIR of a low dose of isoproterenol (10−8M) is similar to that of other agents (e.g. elevation of calcium concentration), intermediate doses (10−7, 10−6M) cause the curves that characterize the FIR (monophasic for the control and the low dose) to become biphasic; large doses (10−5M) strikingly accentuate this effect turning post-extrasystolic potentiation into post-extrasystolic depression. Propranolol (10−7M) and practolol (10−6M) blocked these effects competitively whereas phentolamine (5 × 10−6M) and isopropylmethoxamine (5 × 10−6M) did not. Thus, the effect of changing the FIR from a monophasic to a biphasic function can be deemed a β1 action, unrelated to α or β2 sites. Norepinephrine (10−7, 10−6, and 10−5M) produced the same results. Methoxamine (10−3, 10−4M), not usually considered a β agonist, also produced this same effect on the FIR. These results demonstrate the potential usefulness of the FIR as a means of identifying and classifying inotropic agents as well as providing a method of analysis for testing hypotheses concerning the mode of action of β1 agonists.

SUMMARY (1) The behaviour of the August 1936 Galatea fire in the foothills of the Canadian Rocky Mountains was reconstructed with respect to the rate of spread, frontal-fire intensity and fuel consumption, and illustrates that tree mortality, seed dispersal distance into the burn and condition of the seed bed can be understood from these fire behaviour variables. (2) The fire followed a dry period caused by a blocking high pressure system over Alberta. (3) Major fire runs occurred only three times in the duration of the fire. (4) Differences in fuel appeared to play a minor role in the pattern and behaviour of the fire because of small differences between fuel types and the extremely dry conditions. (5) Fire burned within one topographic basin and within a basin elevation appeared to have little effect. Wind speeds seem to be most important in determining fire behaviour. Fire effects were reduced in areas adjacent to water bodies and in valleys at right angles to, or upwind of, the fire spread direction. (6) Canopy mortality was almost complete due to the low moisture content in fuels and high frontal-fire intensity.

The Ordos Basin of north-central China is well known for vast energy resources. This nonmarine interior basin developed on the North China-Korean platform following the Late Triassic Indochina orogeny and, for a time, contained a large freshwater lake prior to being uplifted into its present form at the close of the Mesozoic. Lower to Middle Jurassic coal occurs in the fluviolacustrine Yan9an Formation along the southern margin of the basin in the Huanglong coalfield. In the northeast part of the field, the formation ranges from 0 to 180 m in thickness and is divided into five fining-upward members, each representing a regressive-transgressive lacustrine cycle. Low-sulfur, high-volatile bituminous coal is complexly distributed in the lowest member of the Yan9an Formation. Deposition of this member was influenced by two tectonic events that controlled coal occurrence. First, regional uplifts were produced by the Late Triassic Indochina orogeny and left as highlands on the pre-Yan9an, Triassic land surface; in the lowest member, coal beds thin toward and pinch out against these highlands. Second, syndepositional tectonism of the Jurassic through Cretaceous Yanshan orogeny created a series of northeast-trending folds that were topographically expressed as evolving highs and lows. Swamps and resulting peat accumulation preferentially occupied the subsiding paleodepressions. Because of the tectonic influence on peat accumulation, coal beds thin and merge toward anticlines and thicken and split toward synclines. In addition, coal quality is documented to be less variable along a northeast trend than along a northwest trend.

A variational principle is presented which characterizes steady motions, at finite Rossby number, of rotating inviscid homogeneous fluids in which horizontal velocities are independent of depth. This is used to construct nonlinear solutions corresponding to stationary patches of distributed vorticity above topography of finite height in a uniform stream. Numerical results are presented for the specific case of a right circular cylinder and are interpreted using a series expansion, derived by analogy with a deformable self-gravitating body. The results show that below a critical free-stream velocity a trapped circular vortex is present above the cylinder and a smaller patch of more concentrated vorticity, of the opposite sign, maintains a position to the right (looking downstream) of the cylinder. An extension to finite Rossby number and finite obstacle height of Huppert's (1975) criterion for the formation of a Taylor column is presented in an appendix.

The force frequency relationship (FFR) describes the way cardiac contractility depends on the rate and pattern of stimulation. The FFR fulfills one of the requirements for an index of contractility: When the maximum rate of tension developed in a contraction (Fmax) is used to measure contractility, the FFR is independent of muscle length. (Circ. Res. 33:665, 1973) We show here that the FFR also fulfills another requirement for an index of contractility, namely that changes in the inotropic state of the muscle are distinguishable from changes in muscle length. Inotropic changes in the FFR fell into three classes: 1. Both ouabain (5×10−7M) and increase in Ca concentration (up to 10mM) increased contractility following the regular contraction much more than following an extrasystolic contraction. 2. Phenylephrine 5×10−5M increased contractility following the extrasystolic contraction much more than following the regular one. 3. The actions of isoproteranol and norepinephrine in small doses 10−6M, Fmax in the steady state contraction exceded that of the post extrasystolic contraction. We conclude that the FFR provides a valuable basis for distinguishing length changes from changes in inotropy and cataloging the actions of positive inotropic agents.

The barotropic potential vorticity equation or topographic wave equation is not linear in topography: the solution structure for topography formed from a sum of obstacles is not the sum of solutions for the obstacles in isolation, even when these individual solutions have identical frequencies. This paper considers the mechanism by which normal modes of oscillation above one mountain are modified by interactions with its neighbours. Exact explicit solutions for the normal modes above a pair of circular seamountains show that the interactions between the mountains rapidly approaches the large-separation approximation obtained by considering solely the first reflection of the disturbance of one mountain at the other. For mountains of one diameter separation at the closest point, the approximation is accurate to within 1%. Perhaps surprisingly, coupling between two identical mountains is weak and resonance occurs between mountains and dales of equal and opposite height. The accurate approximate solutions enable consideration of the effects on a mountain of an infinite set of randomly distributed neighbours. The ensembleaveraged frequency for a mountain of given height is determined in terms of the area fraction of the other mountains. The idea of an effective topography is introduced for the ensemble-averaged stream function: it is that (non-random) topography generating a stream function identical to the ensemble-averaged stream function. This differs markedly from the ensemble-averaged topography. The explicit form of the effective topography is derived for a set of right circular cylinders.

The study documents the timing, prevalence and importance of fires in a 105,000-sq-km area of the Northwest Territories, Canada, bounded by long 1040 and 1120, lat 600 to tree line. Lightning caused most of the fires and accounted for almost all of the area burned in a 7-year period. In this part of the subarctic, the fires appear to follow a seasonal pulse that progresses in June and July from the SW toward tree line in the NE, retreating in August. The normality of fire in this part of the northern boreal zone is beyond dispute. There is no conclusive proof that fire regime has changed substantially in recent times from what it was previously. The implication is that endemic animals, such as caribou, are adjusted to recurring fires.

To the Editor.— In the overtly jaundiced patient, the oral cholecystogram tends to be deemphasized as a means of elucidating the underlying disease, because jaundice is so often associated with hepatic dysfunction impeding excretion of contrast agents into the bile. 1 There are, however, diseases capable of producing severe jaundice due to an isolated and quite specific metabolic defect, such as diminished ability of the liver to convert bilirubin into bilirubin glucuronide, as in Gilbert's syndrome. 2 Becasue the hyperbilirubinemia of Gilbert's syndrome appears to be due to faulty bilirubin metabolism alone, one would expect to obtain a normal oral cholecystogram readily in a patient with this syndrome, even in the presence of marked icterus. This hypothesis was borne out in one patient. Report of a Case.— A 17-year-old man had had intermittent yellow discoloration of his sclerae and skin for several months, which was becoming more persistent and intense.

RUPTURE OF the urinary bladder which is not associated with instrumentational or external trauma is uncommon. Sporadic reports of spontaneous bladder rupture have appeared,* but in the majority of instances outlet obstruction or primary bladder wall disease, ie, tuberculosis, have been obvious and long-standing precursors to the acute episode. In the past three years seven patients with what could be termed spontaneous vesical rupture have been observed at the University Hospital. The primary clinical picture on admission in six of these patients was one of a nonspecific acute abdomen of peritonitis. In five of the patients the bladder perforation either was not initially considered or was delineated only by virtue of the routine utilization of cystography in an acute abdomen of obscure etiology. Report of Cases Case 1 (02-34-98). —A 69-year-old male diabetic was admitted to the general surgery service with a three-day history of nausea, vomiting, and abdominal pain.

The author, considering it probable that two or more magnetic needles freely suspended at a certain distance in given positions with respect to each other, would develope certain proportionate deflections determined by their position on the earth, made a set of experiments, with a few common compass needles, at Yarmouth, London, and Clifton, which so far confirmed the truth of his conjecture, as to induce him to fix on stations at a greater distance from one another, and to multiply his observations; ascertaining, from time to time, that the magnetic powers of his apparatus had undergone no material change. The results of these observations are given in a tabular form. The author conceives that comparative observations of the amount of deflection produced by one magnet on another, placed in various situations, relative to the meridian, on an horizontal plane, will afford the means of determining the peculiar local influences of the particular situation in which the experiment is made, as distinguished from the general magnetic influence; because the former will act unequally on each magnet, while the latter acts equally on all.