Showing papers by "University of Florida published in 1977"

The cepstrum: A guide to processing

Abstract: This paper is a pragmatic tutorial review of the cepstrum literature focusing on data processing. The power, complex, and phase cepstra are shown to be easily related to one another. Problems associated with phase unwrapping, linear phase components, spectrum notching, aliasing, oversampling, and extending the data sequence with zeros are discussed. The advantages and disadvantages of windowing the sampled data sequence, the log spectrum, and the complex cepstrum are presented. The influence of noise upon the data processing procedures is discussed throughout the paper, but is not thoroughly analyzed. The effects of various forms of liftering the cepstrum are described. The results obtained by applying whitening and trend removal techniques to the spectrum prior to the calculation of the cepstrum are discussed. We have attempted to synthesize the results, procedures, and information peculiar to the many fields that are finding cepstrum analysis useful. In particular we discuss the interpretation and processing of data in such areas as speech, seismology, and hydroacoustics. But we must caution the reader that the paper is heavily influenced by our own experiences; specific procedures that have been found useful in one field should not be considered as totally general to other fields. It is hoped that this review will be of value to those familiar with the field and reduce the time required for those wishing to become so.

Transient Asymptomatic S-T Segment Depression During Daily Activity

Abstract: The significance of asymptomatic episodes of ischemic type S-T segment depression was studied in 20 patients with coronary heart disease. Continuous 10 hour electrocardiographic recordings accompanied by detailed daily diaries of activity and symptoms were obtained periodically during a mean time of 16 months. All patients had ischemic type S-T depression associated with angina pectoris during treadmill exercise. Measurements of heart rate, S-T depression and exercise level at the onset of angina obtained during repeated controlled exercise tests at the start of each study period were compared with the measurements recorded during daily activity. After 2,826 hours of recording, 411 transient epidsodes of ischemic type S-T depression were noted during usual daily activity. Only 101 (25 percent) of these episodes were associated with angina. The remaining episodes were unrelated to other symptoms or to posture. All occurred at heart rates significantly lower than those observed at the onset of angina during exercise testing. Of these episodes of asymptomatic S-T depression, 72 percent occurred only at rest or during very light activity such as slow walking or sitting. Nitroglycerin administered hourly significantly reduced the frequency of these episodes, thus supporting the concept that they represent painless ischemia. Because the episodes of asymptomatic ischemic type S-T depression occurred more frequently than angina during usual daily activity and were evident at heart rates and activity levels well below those expected to evoke ischemia, they may be caused by factors other than those that cause angina.

Properties and Management of Soils in the Tropics

Abstract: The long-awaited second edition of this classic textbook expands on the first edition to include advances made in the last four decades, bringing the topic completely up to date. The book addresses critical issues such as whether humanity can feed itself, and whether it can do so in environmentally sound and sustainable ways. Written from agronomic, environmental, and ecological standpoints, the textbook employs a multidisciplinary approach, including policymaking and plant genetic improvements, as well as ecosystem services, climate change, biodiversity, sustainability and resilience. New chapters in this second edition focus on organic carbon in soil, soil biology, soils in relation to livestock production and forestry, and agroforestry. The new edition will again be the go-to textbook for courses on tropical soils, and a reference textbook for soil and agricultural scientists and development professionals working in the tropics.

Physical chemistry of glass surfaces

Abstract: Six typical problem areas requiring improved understanding of glass surfaces are identified. Results obtained from several surface-analysis instruments show that five types of surfaces are characteristic of a silicate glass at any time in its history. The type of surface is dependent on the environmental history of the glass and may be defined in terms of surface compositional profiles. Several important glass surface topics of current interest are discussed. These include: corrosion mechanisms; mixed-alkali effect; surface passivation with solution ions; protective film formation; the role of CaO, R 2 O/SiO 2 and Al 2 O 3 in glass corrosion; glass surface area to solution volume ratio; relevance of autoclave procedures in durability tests; and bioglass-bone bonding mechanisms.

Semantic facilitation without association in a lexical decision task.

Abstract: Subjects were shown pairs of letter strings and had to decide as quickly as possible whether both strings were words. The word pairs included associates (e.g., cat-dog), words not normatively associated that had been rated by other subjects as semantically similar (e.g., nurse-wife), and unrelated control pairs (e.g., bread-stem). Both associates and semantically related pairs were responded to more quickly than were the corresponding control pairs. The magnitude of the facilitation for the associates appeared to be related more to the semantic similarity ratings than to measures of either direct or indirect associative strength. It was concluded that the encoding of a word can be facilitated by the prior processing of a semantically related word.

Rectal colonization with group B streptococcus: relation to vaginal colonization of pregnant women.

Abstract: Anorectal carriage as a possible primary source of vaginal colonization by group B Streptococcus was investigated. The study was performed during two separate periods and included 789 pregnant women and 422 neonates. Specimens from multiple sites were obtained for culture from all women and infants and were streaked onto blood agar plates containing 8 mug of gentamicin sulfate/ml and 15 mug of nalidixic acid/ml, which allow selective growth of streptococci. Cultures positive for group B streptococci were obtained from 162 (20.5%) of the pregnant women and from 50 (11.8%) of the neonates. Rectal cultures were positive for streptococci in 142 (17.9%) of the women, and vaginal cultures gave positive results in 81 (10.2%). The higher incidence of positive results in rectal as opposed to vaginal cultures (ratio of 2:1) was encountered during all phases of the study. This finding suggests that the gastrointestinal tract may be the primary site of colonization by group B Streptococcus and that vaginal colonization may represent contamination from this source.

Influence of extracellular polysaccharides on the toxicity of copper and cadmium towardKlebsiella aerogenes.

Abstract: Many investigations have reported the effects of heavy metals on pure cultures of bacteria (14, 21, 30), algae (3, 22, 25), and on natural microbial populations (1, 2, 17). Most of the studies have focused on copper toxicity because copper sulfate has been used as an algicide since the turn of the century (3, 22, 24, 25). The assessment of the toxicity of heavy metals toward microorganisms must take into account the physicochemical parameters of the water (17, 23, 24) and the presence of chelators in natural waters. Natural (humic acids, amino acids, polypeptides) and artificial (EDTA, Nitroloacetate) chelators form organic complexes with metallic ions and thus alter the availability of these toxic metals to aquatic microorganisms (10, 19, 20, 24, 28). Microorganisms are known to produce large quantities of extracellular polysaccharides which are organized in well-defined capsules around the cells, or are excreted as loose materials into the growth medium. The ecological significance of these polymetric materials has been previously discussed (13, 15, 27). However, among the various functions assigned to extracellular polysaccharides, their ability to bind metallic ions has received little attention (11, 26). In this study we report the effect of capsular polysaccharides on copper and cadmium toxicity toward Klebsiella aerogenes. This particular bacterium was chosen because we had a noncapsulated mutant which could be compared to the encapsulated strain.

Electron impact on atmospheric gases, I. Updated cross sections

Abstract: The analytic characterizations of electron impact cross sections for important atmospheric gases (namely, O2, N2, O, CO, CO2, and He) are updated. With these cross sections it is simple to communicate massive quantities of experimental and theoretical results. In addition, these forms are convenient for applications in energy degradation calculations, including a new approach described in a companion paper.

Summer Habitat and Ecology of the Endangered Indiana Bat, Myotis sodalis

Abstract: A nursery population of M. sodalis was discovered in Indiana and studied for 2 years. The nursery roost was located under the loose bark of a dead tree. Sometimes the bats temporarily moved to bark crevices of a living shagbark hickory tree. Weather strongly affected roost microclimate. The nursery tree was unshaded and received maximal solar warmth during clear, mild or hot weather, whereas temperature at the shaded alternate tree was more stable during spring and autumn cold. The nursery population consisted of adult females and young, and few males were netted in local foraging areas. Each female bore a single young and these incurred eight percent mortality between birth and weaning. Social behaviors included “checking,” mothers carrying young to an apparently warmer portion of the roost tree, and apparent mother-young foraging flights as the young became volant. Unusually cool weather in summer 1974 slowed the growth of young; this delayed recruitment of flying young more than 2 weeks and the completion of migration by 3 weeks. The delay exposed some bats to freezing weather at the nursery and may have affected mortality, autumn mating, or fat storage for winter. No problems were evident during the favorable summer of 1975. Foraging habitat included the foliage of riparian and floodplain trees, and the 50 bats used a 0.82 kilometer (km) linear strip of creek. Similar habitat was used by two other populations in Ohio. Before young were volant, adults fed only about riparian trees; when young began to fly, feeding extended to solitary trees and forest edge on the floodplain. This reduced foraging density from 17 to 11 bats per hectare (ha). Suitable foraging habitat occurs over much of the eastern United States, and use of local trees for nurseries makes a large summer distribution possible. Humans also value floodplain habitat, and a land use conflict exists between the two species.

Effects of Lidocaine on the Anesthetic Requirements for Nitrous Oxide and Halothane

Abstract: The effects of various plasma concentrations of lidocaine on nitrous oxide anesthesia in man and halothane requirements in the dog were studied The response to incision of the skin was observed in 20 patients who were anesthetized with nitrous oxide, 70% inspired, and oxygen, 30%, plus various plasma levels of lidocaine In addition, changes in the MAC of halothane in dogs were observed at various levels of lidocaine In both circumstances lidocaine concentrations of 3 to 6 microgram/ml decreased anesthetic requirements approximately 10 to 28% At clinically common concentrations of lidocaine, significant decreases in anesthetic requirements should be anticipated

Proposals for a stable classification of the Phlebotomine sandflies (Diptera: Psychodidae)

Abstract: . A practical system of classification and nomenclature for the Phlebotomine sandflies of the world is suggested, in the light of a re-examination of the early taxonomic literature and a critical appraisal of recent studies. A stable and simple classification of the sandflies as the subfamily Phlebotominae, family Psychodidae, is given, in which are recognized only five genera but a larger number of subgenera, species groups and lesser, informal, categories. The various groupings, many of which are discussed, are considered to form a stable general framework with flexible subdivisions into which recent and future ideas may be assimilated. The system should cause minimum confusion and give maximum ease of data-retrieval to taxonomists and other scientists concerned with the classification of sandflies for pure or applied purposes.

On the role of "memory" in the analysis of behavior.

Abstract: Shimp's (1976) recent paper on memory and the structure of behavior is discussed, as is the concept of memory itself. Radical behaviorism is distinguished from associationism, and behavioral accounts of experiments on short-term and long-term memory are provided. Unobservable theoretical quantities, such as rate of response, are distinguished from theoretical constructs such as memory. The logical inconsistency involved in the use of short-term memory as a "theoretical primitive" in the definition of units of behavior is explicated, and an alternative strategy for identifying units of behavior is presented. It is argued that the experimental analysis of behavior has ignored processes usually considered as memorial because many of the phenomena are irreversible. Methods for the study of transitions in single subjects should be developed more fully. Possible pitfalls associated with subscription to the term memory are listed, and it is concluded that the concept is neither required nor helpful in the analysis of behavior.

Circadian periodicities of serum androgens, progesterone, gonadotropins and luteinizing hormone-releasing hormone in male rats: the effects of hypothalamic deafferentation, castration and adrenalectomy.

Abstract: Serum testosterone (T), dihydrotestosterone (DHT), progesterone (P), LH, FSH and luteinizing hormone-releasing hormone (LHRH) levels and the LHRH content in the medial basal hypothalamus (MBH) and preoptic area (POA) were estimated during a 24-h period. Circadian rhythms, temporally unrelated to each other, were evident in serum FSH and LHRH and the MBH LHRH content; serum LH fluctuated randomly. In addition, serum T and DHT demonstrated a parallel circadian pattern while serum T and P appeared inversely related. Serum P rhythm persisted in long-term castrate males. Without adversely affecting serum LH, anterior hypothalamic deafferentation abolished both serum T and P rhythms, whereas adrenalectomy obliterated only the serum T periodicity. These studies show that the POAMBH complex and the adrenals play important roles in the circadian regulation of testicular secretions.

Processes involved in mathematical problem solving

Abstract: grade subjects learned to solve nonroutine geometry problems and (b) changes in those processes as the problem-solving ability of the subjects developed. The second, more important section indicates a direction for future research in problem solving and sets forth suggested hypotheses for investigations, both clinical and experimental, resulting from reflection on the regularities observed in the problem-solving behaviors of the first section. The Study Mathematics educators agree that the development of the ability to solve complex, nonroutine problems is one important goal of mathematics instruction. An individual is faced with a problem when he encounters a question he cannot answer or a situation he is unable to resolve using the knowledge immediately available to him. He must then think of a way to use the information at his disposal to arrive at the goal, the solution of the problem. A problem differs from an exercise in that the problem solver does not have an algorithm that, when applied, will certainly lead to a solution. To complete an exercise, one must first determine the applicable algorithm,

The pharmacology of methazolamide in relation to the treatment of glaucoma.

Abstract: Methazolamide, a carbonic anhydrase inhibitor of strength equal to acetazolamide but with very different physicochemical properties and body distribution, was studied in animals and in man. Particular attention was given to ocular effects and to pharmacology pertinent to the treatment of glaucoma. Due to relatively good lipid solubility and low plasma protein binding, methazolamide diffuses into tissues and fluids much more readily than acetazolamide. Methazolamide is well absorbed and has a plasma half-life in man of 14 hours. Unlike acetazolamide, it is neither secreted nor concentrated by the kidney and at equal threshold doses produces less renal effect. Conversely, because of better diffusion, it is more active on a weight basis in reducing aqueous humor secretion. These facts open the possibility that methazolamide may have a selective action on the eye. At 1 to 2 mg./kg. in animals, or 25 mg. every 12 hours in man, there was lowering of intraocular pressure with no renal loss of HCO's. Patients or volunteers showed no adverse reactions on this schedule, which is \\^o the daily dose of acetazolamide. Pressure lowering after methazolamide in the absence of acidosis, however, was less than during acidosis, either induced by larger doses of methazolamide or by acetazolamide. This agrees with experimental data showing that systemic acidosis and the local effect of carbonic anhydrase inhibitor at the ciliary process are additive in reducing pressure. Methazolamide, in this low dose, offers the possibility of treating glaucoma without acidosis or side effects, including renal stones, although the magnitude of the lowered ocular pressure is less than that which follows present schedules of this drug or of acetazolamide.