Showing papers by "University of Florida published in 1974"

Pattern recognition principles

Abstract: The present work gives an account of basic principles and available techniques for the analysis and design of pattern processing and recognition systems. Areas covered include decision functions, pattern classification by distance functions, pattern classification by likelihood functions, the perceptron and the potential function approaches to trainable pattern classifiers, statistical approach to trainable classifiers, pattern preprocessing and feature selection, and syntactic pattern recognition.

Wait-Time and Rewards as Instructional Variables, Their Influence on Language, Logic, and Fate Control: Part One--Wait-Time.

Abstract: Cet article a ete reconnu par la communaute de chercheurs comme etant un des articles les plus importants jamais publies dans ce periodique. L'auteur y traite d'un element qu'elle nomme wait-time et qui correspond au temps d'attente entre le moment ou l'enseignant cesse de parler et celui ou l'eleve repond ou celui ou l'enseignant reprend la parole. Cette theorie presenta une utilite pour tous les enseignants, toutes disciplines confondues et a tous les niveaux de l'education.

Nonhistone Chromosomal Proteins and Gene Regulation

Abstract: Evidence from several model systems suggests that nonhistone chromosomal proteins may regulate gene expression in eukaryotic cells. The data indicate that the synthesis of new species of nonhistone chromosomal proteins as well as modifications of preexisting nonhistone chromosomal proteins are involved in the control of transcription. However, from the vast number of proteins included in this class, it is apparent that, in addition to regulating the transcription of defined genome loci, the nonhistone chromosomal proteins include enzymes that have a general function, proteins that are involved in determining the structure of chromatin, as well as proteins that serve as recognition sites for binding of regulatory macromolecules. The presence of a nucleoplasmic pool of nonhistone chromosomal proteins which may exchange with the chromatin has also been reported (89). While it is clear that the nonhistone chromosomal proteins play a key role in the regulation of gene expression, the exact manner in which they interact with the genome to initiate, modify, or augment the transcription of specific RNA molecules remains to be resolved.

The middle ultraviolet reaching the ground

Abstract: — We present a semi-empirical analytic formula for calculating the direct, diffuse and global solar middle-ultraviolet radiation (280–340 nm) reaching the ground. The formula accommodates variations in wavelength, solar angle, ozone thickness, aerosol thickness, ground albedo, ground elevation, and cloudiness. Analytic representations of biological action spectra are also presented for use in calculations of effective dose at any time of day. Our purpose is to provide a basis for estimating approximate changes in middle-ultraviolet radiation levels reaching the ground caused by anthropogenic changes in the intervening atmosphere.

Improved corneal storage.

Abstract: The corneas of New Zealand albino rabbits were isolated with a sclero-corneal rim for storage in a modified tissue culture medium (M-K medium) at 4° C. The corneas were either mounted in the specular microscope for daily observation of the endothelial layer and comeal thickness while being bathed in the storage medium at 4° C, or sealed in vials with the storage media. The vials were stored at 4° C. for 5, 9, and 14 days at the end of which the corneas were mounted in the specular microscope and the temperature was reversed for an endothelial viability test. Along with specular micrographs of the endothelial layer and comeal-thickness measurements, electron microscopy was performed to evaluate the viability of the endothelial cells. The results have indicated that a viable endothelium is present in rabbit corneas stored for up to 14 days in the M-K medium. The corneal storage technique requires no special equipment, utilizes readily available storage media components, and is easily executed with little chance of technician error. It not only permits prolonged storage, but it is superior to the stagnant aqueous of the enucleated eye.

Vorticity Associated with a Jet in a Cross Flow

Abstract: An extensive wind-tunnel test of a round turbulent jet directed normally through a flat plate into a subsonic cross flow has been conducted. The results of the velocity field measurements are presented in a concise and usable form through the use of simple models to relate the velocity field to empirical values for the strength and location of the pair of contrarotating vortices associated with the jet.

On the foundations of polar geometry, II

Abstract: One of the two Buekenhout-Shult theorems for polar spaces required a finite rank assumption. Here we get rid of that restriction. Similarly, the polar spaces of possibly infinite rank having some line of two points are classified.

Histochemical responses at a biomaterial's interface

Abstract: A series of nonporous glasses and glass materials designed with controlled surface ion activities to allow chemical bonding to bone are described Surface reactivities of these materials in vitro are correlated with biological activities in vivo and in tissue culture Direct chemical bonding of the materials to bone is demonstrated The mechanism for development of this bond is through the production of an amorphous ion surface gel on the bioglass This gel induces osteogenesis by a chemotactic response of osteoblasts

Mechanism of steady-state grain growth in aluminum

Abstract: Grain growth, defined as the increase in volume of the average grain, is found, in its steadystate, to be directly proportional to the time of isothermal annealing. During steady-state grain growth the grain corners are found all to be quadruple points, the grain edges all triple lines and the ratio of corners to faces to edges to be 6:7:12. The rate constant for steady-state grain growth is shown to be calculable from first principles and from properties that can be measured independently of the growth observation. It is the product of four individual constants, namely: 1) a dimensionless topological constant ⊝ that is characteristic of steady-state grain growth in any material, 2) the mobility ώ of the average grain boundary in the specific material, 3) the surface tension y of the average grain boundary in the specific material and 4) a dimensionless structural constant σ which expresses the curvature of surface of the grain boundary in the array of grain forms obtaining in the specific specimen of the material and which can be determined metallographically. The topological changes that constitute steady-state growth are shown to exist as a logical sequence of simple events.

The effects of a chronic limitation of sleep length.

Abstract: Fifteen male subjects (Ss) were studied once each week while on a sleep regime of 5 1/2 hrs of sleep a night for 60 days. The electroencephalogram and electro-oculogram were recorded in the laboratory once each week. Performance was measured each week using the Wilkinson Vigilance Task, the Wilkinson Addition Test, and a word memory test, and grip strength was measured using a hand dynomometer. The Zung Depression Scale and the Gough Adjective Check List were used to measure mood. The Ss completed a sleep log on a daily basis. The effect on sleep of the restricted regime was to initially increase the absolute amount of stage 4 sleep. But by the 5th week of the study the stage 4 amount decreased to near baseline levels. The initial effect on REM sleep was to sharply reduce this type of sleep when compared with baseline values. During the course of the experiment there was a REM deprivation of some 25% of baseline values and 30 min in absolute amount. During the course of the experiment the latency to the onset of the first stage 4 and the latency to the first REM period were reduced. Only the Wilkinson Vigilance Task showed a decline in performance associated with continued restricted sleep. The sleep logs revealed that initially the Ss experienced difficulty in arousing from sleep in the morning and felt drowsy during the day, but these effects did not continue throughout the experiment. The mood scales showed no changes associated with continuing to sleep 5 1/5 hrs a night. These findings suggest that a chronic loss of sleep as much as 2 1/2 hours a night is not likely to result in major behavioral consequences.

Temporal interrelationships among circulating levels of estradiol progesterone and LH during the rat estrous cycle: effects of exogenous progesterone.

Abstract: Serum progesterone (P) levels display a circadian rhythm of varying amplitude during the estrous cycle. This rhythm is characterized by lowest levels of the day around noon and maximal levels at 1600 or 2300 hr. Amplitude was smallest on estrus and progressively greater on diestrus II, diestrus I and proestrus. Serum estradiol (E2) concentrations declined gradually through estrus till 0800 hr of diestrus I. Thereafter, levels increased rapidly to peak at noon, and returned later to near nadir at 2300 hr of diestrus I. During diestrus II and morning of proestrus serum E2 concentrations increased in a biphasic pattern; a moderate increase till 1800 hr of diestrus II was followed by relatively rapid rise to peak levels at 0800 hr of proestrus. A reciprocal relationship between circulating levels of E2 and P during the estrous cycle was also detected. The elevations in serum P levels during estrus, diestrus I and proestrus appeared to coincide with a gradual reduction in serum E2 levels. In addition to the su...

Immunity to Infections on Secretory Surfaces

Abstract: The field of immunology developed as attempts were made to understand the observed phenomenon that, in many cases, individuals become immune (often permanently) to an infectious disease after having had that disease. As a natural corollary of this fact, attempts were made to induce this immune state without causing illness, or at least to reduce acceptably the severity of illness. During the past 200 years, the corollary aim has probably proven more successful than the attempts to understand the phenomenon, and the development of the several immunization practices now widely used has been the most successful aspect of the disciplines of immunology and infectious disease (with the possible exception of the role of the latter in the generally improved state of public hygiene). In addition, we feel that this contribution from the combined efforts of those in the fields of infectious diseases and immunology will continue to be great, e.g., in the development of vaccines against caries, herpesvirus, and streptococcal infections, the hepatitides, gonorrhea, and syphilis, and in improved vaccines against cholera and influenza.

Relation of wait-time and rewards to the development of language, logic, and fate control: Part II-Rewards

Abstract: In Part I it was shown that by varying the duration of pauses in two locations the length of student statements increased, the number of alternative explanations offered multiplied, and the overall probability of receiving a reply increased. It was noted, as well, that in natural situations where there was a high incidence of teacher sanctioning behavior, regardless of whether it was predominantly positively toned, the verbal performance of students engaged in inquiry appeared to be negatively influenced even when there were reasonable wait-times. That is, even in those rare naturally occurring cases where pauses were longer than the mean of one second, and in experiments where pauses and rewards were independently manipulated if sanctioning behaviors were intense, the positive influence on inquiry of the longer pauses appeared to be somewhat mitigated. It became necessary, then, to study reward patterns in the context of inquiry in order to discover whether, in general, overt verbal rewards which we found occurring with tremendous frequency in natural settings, helped or hindered the progress of student inquiry.

Quantitative Analysis of Glass Structure with the Use of Infrared Reflection Spectra

Abstract: It is predicted theoretically and justified experimentally that infrared reflectances are proportional to the concentrations of the vibrational species causing them. In the binary Li2O-, Na2O-, and K2O-SiO2 glasses used in this study, the reflection peaks have been assigned to vibrations of single silicon-oxygen tetrahedra in different symmetry environments caused by the presence of alkali ions. Care has been taken here in recording the spectra of high alkali glasses to prevent chemical reactions with water vapor in the atmosphere. The influence of phase separation on reflection spectra is also discussed.

Action of Cholinergic and Anticholinergic Drugs at the Crossed Olivocochlear Bundle-hair Cell Junction

Abstract: Both cholinergic and anticholinergic drugs introduced into the scala tympani of guinea pigs were found to block the effects induced by electrical stimulation of the crossed olivocochlear bundle. Strychnine, d-tubocurare, and decamethonium were most potent in this activity. Eserine did not potentiate the effects of electrical stimulation of the crossed olivocochlear bundle but did potentiate the effects of acetylcholine and in high concentrations blocked the crossed olivocochlear bundle. Acetylcholine (247 μM) in combination with eserine (20 μM) mimicked the effects of the crossed olivocochlear bundle by producing an augmentation of the cochlear microphonics and an inhibition of the action potential. The acetylcholine (247 μM)-eserine (20μM) combination also produced a reversible blockade of the crossed olivocochlear bundle and the mimicking effects of subsequent perfusions with the drug combination. The mimicking effect of the acetylcholine (247 μM)-eserine (20 μM) combination was blocked by d-tubocurare....

Discriminations of interaural phase differences

Abstract: Listeners were asked to discriminate between two pulsed sinusoids, one presented with an interaural phase delay θ and the other presented with a longer delay θ + Δθ. Frequency of the sinusoids ranged from 250 to 4000 Hz. The difference threshold for Δθ was defined as the dependent variable. This threshold increased as θ increased from zero degrees to half the period of the sinusoid, then decreased as θ was further increased to a full period of the sinusoid. As θ was increased to half the period of the sinusoid, the lateral image appeared to shift away from midline toward the ear leading in time; but as θ was increased beyond half a period of the sinusoid, the lateral image appeared to shift toward the midline from the ear lagging in time. These results were obtained at 250, 500, and 900 Hz. At 2000 Hz, the value of Δθ remained a constant as θ was varied, while at 4000 Hz the lateral image was not moved by any interaural delay. The results imply that (1) for frequencies less than 2000 Hz, lateral discriminations based on interaural phase differences are more acute toward midline than at either side, and (2) for frequencies greater than 2000 Hz, changes in interaural phase are unable to shift the lateral image.

Effects of ionizing radiation on mammalian cells

Abstract: Soon after the discovery of ionizing radiation its beneficial and damaging effects on human health were noticed and scientists became interested in the physical interactions of radiation energy with living material and the resulting biological effects. Since that time environmental and accidental exposure to ionizing radiation has become a threat to the general population. In this article recent progress in the radiobiology of rapidly dividing mammalian cells in culture is discussed. Special emphasis is placed on the lethal, mutagenic and carcinogenic effects of ionizing radiation. These detrimental effects of ionizing radiation result, for the most part, from damage induced in the nuclear deoxyribonucleic acid (DNA). The formation and repair of radiationinduced breakage of one or both strands of the double stranded DNA helix and of damage to the heterocyclic nucleic acid bases are actively being investigated in mammalian cells. While important progress has recently been made, most of the DNA lesions produced in situ in the cell have not been chemically identified. The relation of the DNA damage to the impairment by ionizing radiation of the cellular functions leading to cell death, mutation and malignant transformation remains unknown.