ALBERT

Notes: Abstract We derive upper limits to the radiation temperaturesT t(k) for emission near the fundamental and second harmonic of the electron plasma frequency in terms of the effective temperature for plasma wavesT l(k′). We findT t(k)≲(c/(3)1/2 V e)3 T l(k′) for emission near the fundamental which differs from the result of Melrose (1970b) by the factor in parentheses. This factor can exceed 4×104 in some plasmas. The conditions under which this limit could be reached are delinated. For emission near the second harmonicT t(k)≤T l(k′) since the absorption coefficient in this case can only be positive.

Notes: Summary The gliding locomotion of planaria (Dendrocoeleum lacteum) was suppressed similarly by LiCl and RbCl.

Notes: Summary Injection of hypertonic LiCl i.p. has several nonspecific adverse effects in rats. No evidence was obtained forJohnson's hypothesis that the effect of LiCl on rearing is mediated by environmental stimuli.

Notes: Abstract It is now possible to divide particulate primary production into algal and heterotrophic components without physical separation. This depends on two innovations, the introduction of isotope in the form of labelled dissolved product(s) of primary production and the employment of a data analysis specifically designed for tracer kinetic incorporation experiments. The 14C technique described by Steemann Nielsen (1952) is inapplicable in the analyses of certain classes of systems and kinetic tracer incorporation experiments must be employed instead. We show that measurement of PDOC production rate requires such kinetic tracer analyses. Measurements made in the laboratory on water taken from 2 m depth in South West Arm of the Port Hacking estuary showed that: (1) the steady-state rate of PDOC production was 0.10 to 0.13 mg C.m-3.h-1; (2) the rate of PDOC incorporation into microheterotroph particulate organic carbon was 0.10 to 0.12 mg C.m-3.h-1; (3) the rate at which PDOC was respired to CO2 was 0.001 to 0.003 mg C.m-3.h-1. (4) the PDOC makes up only about 0.1% of the total dissolved organic carbon. The size class of particles associated with PDOC production differed from the size class responsible for uptake of PDOC. More than 50% of the PDOC production was associated with particles having a nominal diameter range of 20 to 63 μm, while this fraction was responsible for 〈10% of the incorporation.

Notes: Abstract Rates of change in oxygen concentration can be measured in the laboratory and in natural waters by using a measuring system consisting of two independent oxygen electrodes sending readings to a minicomputer ten times per second. Laboratory and experimental measurements were made under the control of the minicomputer, and differ from those made using standard approaches in two regards. First, the computer removes some of the statistical fluctuation in the data by selectively saving readings only when both electrode readings have changed in the same direction. Second, the computer alters the frequency at which data points are collected during the experiment. A predetermined number of data point pairs consisting of oxygen concentration values and time are collected by the computer. A linear regression analysis is conducted and the values of slope, intercept, sums of squares, and linear correlation coefficient are calculated and printed out. Next, the average of the absolute displacement of the data points about the regression line is calculated. Using the previously acquired value of slope, the computer calculates the length of time required for the change in oxygen concentration to be twice the average dispersion of data points about the regression line. This length of time over which n data points are to be collected is divided by (n-l) to give the waiting period between the samplings in the next round of data acquisition and linear regression. By employing a minicomputer to dynamically alter the experimental sampling frequency and to select the data points to be retained for the subsequent linear regression, it is possible to routinely obtain respiration rate estimates smaller than 20 μM (O2) h-1 with associated linear correlation coefficients exceeding 0.97. This system has enabled us to measure the rates of oxygen production and consumption in nearshore water samples using light/dark incubations. On 24 March 1981, it was found that following the influex of the kelp Ecklonia radiata (C. Ag.) J. Agardh to nearshore waters off Perth, Western Australia, the rates of oxygen evolution and consumption by the particulate fraction (nominal diam〈124 μm) increase exponentially for the first 10 h. Subsequently, the rate of change of oxygen in the light decreases to the same negative value as that measured in the dark incubation. This time-varying dark respiration rate, if analyzed as an exponential function, has a doubling time of 8.2 h, a value consistent with bacterial growth rates at the ambient water temperatures (19° to 20°C).

Notes: Abstract Tracer kinetic analysis of radioisotope incorporation into dissolved organic compounds reveals two distinct patterns of photosynthate release by macroalgae. In experiments employing Sargassum lacerifolium, dissolved organic carbon was produced at a constant rate during light incubations. Steady state rates of production were never achieved in experiments employing either Ecklonia radiata (Turn.) J. Agardh. or Ulva lactuca L. Analysis of the time-varying radioactivity curves obtained in experiments using these algae always resulted in models consistent with dissolved organic carbon production being an autocatalytic process. Preincubation of U. lactuca in the dark resulted in a diminished (ca. 40%) rate of dissolved organic carbon production during the subsequent light incubations. In no case did the radioisotope content of the dissolved organic carbon approach a limiting value, indicating that in contrast to phytoplankton, uptake rates of photosynthate by macroalgae are always less than the rates of production.

Notes: Abstract The generation of lower-hybrid waves by cross-field currents is applied to reconnection processes proposed for solar flares. Recent observations on fragmentation of energy release and acceleration, and on hard X-ray (HXR) spectra are taken into account to develop a model for electron acceleration by resonant stochastic interactions with lower-hybrid turbulence. The continuity of the velocity distribution is solved including collisions and escape from the turbulence region. It describes acceleration as a diffusion process in velocity space. The result indicates two regimes that are determined by the energy of the accelerating electrons which may explain the double power-law often observed in HXR spectra. The model further predicts an anticorrelation between HXR flux and spectral index in agreement with observations.

Notes: Abstract The possibilities for type III burst excitors are reviewed and it is concluded that particle streams are the most likely excitor. Possible methods of resolving the apparent discrepancy between the number of particle events observed in interplanetary space in the vicinity of the earth and the number of type III bursts are indicated. Observations relevant to the excitor are reviewed and translated into requirements for a theory of the exciting stream. Possibilities for an electron stream excitor are considered and it is concluded that, while such an excitor cannot be eliminated at the present time, there are definitely theoretical difficulties with it which can be overcome only by seemingly ad hoc and improbable assumptions. Possibilities for a proton stream excitor are examined and it is found that all theoretical difficulties can be overcome in a natural manner. The number of ≈ 50 MeV protons required to explain a strong type III burst is estimated conservatively as 3 × 1025 which, after diffusion in interplanetary space, would be undetectable by the instruments flown thus far. This number is consistent with some theoretical ideas about the flare mechanism and also with present observational data.

Notes: Abstract A critical examination of the components of the recent impulsive loop flare model of Takakura is made. It is found that his analysis of the stability of the electron distribution resulting from anomalous heat conduction is in error and electron plasma waves would not be excited. Rather, in the regions where the electron/proton temperature ratioT e/T i ≲ 10, electrostatic ion-cyclotron waves would be excited and in the regions whereT e ≳ 10, ion-acoustic waves would be excited. Ratios ofT e/T i ≳ 10 occur only in the late time development behind the conduction fronts. Since the anomalous resistivity due to electrostatic ion-cyclotron waves is fortuitously about 70% of the one used by Takakura, the general development will follow closely the one calculated by him. Because the anomalous resistivity due to ion-acoustic waves is about 95 times the one used by Takakura, the development in the parts of the loop whereT e/T i ≳ 10 for late times would be altered considerably.