Temperature-sensitive mutant of Schizosaccharomyces pombe exhibiting enhanced radiation sensitivity

A conditional lethal and radiation-sensitive mutant of Schizosaccharomyces pombe is described in which both characteristics result from a single gene mutation. Confirmation of the pleiotropic nature of this mutant was obtained by tetrad analysis and by testing the radiation sensitivity of a large number of revertants that grew normally at the restrictive temperature. The colony-forming ability of the mutant after ultraviolet radiation, gamma radiation, and ethyl methane sulfonate treatment is considerably altered by the post-treatment incubation temperature, showing higher survival at 25 than at 30degreesC. The radiosensitivity of the mutant is also influenced by the stage of growth. The difference in radiation sensitivity between the wild type and mutant is greater when log-phase cultures are compared. The characteristics of this mutant suggest that it is defective in a step common to both deoxyribonucleic acid replication and repair.     

Comments on ``Induction Thermocoagulation?A Seed Power Study'

In the above communication, Merry, Hale, and Zervas proposed two eddy-current models of seed implant heating. Their theoretical calculations and experimental observations showed the observed heating falls somewhere between the two models discussed. I wish to note some corrections to the theoretical results which will clearly delineate the applicability of the skin effect model and the inadequacies of the total penetration model.     

ECS in one-trial appetitive learning of rats: Retention and amnesia.

Conducted 4 experiments with 214 male hooded rats to assess the kind and degree of amnesia induced by ECS following a 1-trial appetitive learning experience. Exp I (n = 30) and II (n = 60) show that although there is a definite amnesia that cannot be explained as an artifact of ECS-induced aversiveness, some memory of the experience does survive the ECS. Exp III (n = 96) suggests that this memory is for the novelty aspects of the learning experience, while there is at least a partial amnesia for the positive reinforcement received. Results of a 4th experiment (n = 28) suggest that the ECS has the effect of interrupting or preventing the classification of a novel object as reinforcing or nonreinforcing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The central nervous system and the reinforcement of behavior.

Discusses findings on reward and drive processes, noting that an anatomical study of brain rewards revealed a relatively unified system. Experiments which help clarify the relations between brain-stimulated negative reinforcement or pain behavior are cited. It is hypothesized that 4 learning grids might project from the hypothalamus into places like the cerebellum, tectum, hippocampus, and neocortex. In these grids, rewarding messages would (1) directly augment the frequency of ongoing responses, (2) reinforce certain ongoing synaptic relations, or (3) be recorded in memory elements to serve in relation to remembered behavior patterns. These processes might occur redundantly or simultaneously. (47 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Salmonid Spawning Runs and Estimated Ova Production in Normandale Creek of Lake Erie

The Normandale Creek study area (2,531 m²)provides spawning and nursery grounds for lake-run coho salmon (Oncorhynchus kisutch), rainbow trout (Salmo gairdneri), and brown trout (Salmo trutta), In 1973–74, 59 adult salmonids (58% rainbow trout, 39% coho salmon, and 3% brown trout) ascended the stream between 31 October and 12 May. Upstream movements were significantly related to peak stream discharge (r = 0.21) and highly significantly related to discharge occurring on the day following the peak freshet (r = 0.34). Despite a highly significant correlation (r = 0.29) between flow and water temperature, the latter factor is not significantly related with upstream movement of adult fish. Coho salmon spawned at water temperatures of 1 to 10° C between 2 November and 19 December, rainbow trout at 1 to 15° C between 9 November and 14 May, and brown trout at 7° C between 4 and 5 November. Of 86 nests constructed, 60% were disturbed by re-use or sand deposition. From a calculated deposition of 90,403 ova, it is estimated that some 22% survived to emergence.     

Winter Temperature Structure in Lake Huron

Water temperatures at depths 15, 25, and 50 m below the surface and 2 m above the bottom were continuously recorded at 17 mooring sites in Lake Huron during the 1974–75 winter. Monthly isotherm patterns show that the shore regions rapidly cooled to near 0° C by early February, while the deep northern basin reached a minimum of 1.5° C in mid-April. The initial stages of the fall overturn at depths greater than 100 m exhibited temperature fluctuations due to wind mixing and advection. By mid- to late December, Lake Huron was isothermal at all recording stations and remained so through April, except in the deep basins where a weak winter thermocline developed in March.     

The resource trichotomy

There are three basic material resources: Materials, Energy, and the Environment. One can no longer be studied intelligently without considering the other two. Other than human and spiritual resources, which are equally involved, all resource considerations can be included in these three categories. The cleavage that has developed among those most deeply involved in the three resource areas is a frequently bitter trichotomy. Each of the three involves vast areas of ignorance as well as tremendous vistas of knowledge. Inter-communication among the disciplines in terms that the layman can understand is as essential as the basic scientific work itself. And it will not happen until the trichotomy becomes what it used to be—a trinity of interest rather than a deep cleavage.     

Statistical Analysis of Power Consumption in Surface Grinding

A method of identifying the individual as well as the combined effects of the different independent factors on the power consumption in the grinding process is presented. Physical experimentation coupled with subsequent statistical analysis, the factorial experimentation technique, was applied to further the understanding of this process. Mathematical models were developed to estimate the level of the dependent factor, the power consumption. Optimum conditions that result in the lowest level of power consumption with the maximum rate of metal removed are evaluated and discussed.     

A-B variable and reactions to nonimmediacy in neurotic and schizoid communications: A longitudinal analogue of psychotherapy.

Selected 36 A- and 36 B-type male undergraduates from the scores of 225 Ss on a 19-item version of the A-B scale. Ss responded verbally and therapeutically to neurotic and schizoid videotaped enactments displaying improvement, no change, and deterioration over the course of psychotherapy and exhibiting high and low conditions of verbal nonimmediacy in their communications to the therapist. A types were more immediate with the schizoid, and Bs with the neurotic, communications. Results concerning the longitudinal response to the changing display of nonimmediacy were equivocal, but subjective reaction conformed to expectancies and there was other, indirect support for the longitudinal hypothesis. Substantive conclusions are drawn concerning verbal nonimmediacy in relation to therapist-patient compatability-incompatability and as a potential intrachannel process variable in psychotherapy. The nonimmediacy model is confirmed and extended in a complex, ongoing, dyadic interaction. (24 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)