Showing papers by "University of Florida published in 1979"
TL;DR: Experiments with pure plant hormones showed that gibberellin causes increased production of lateral roots, andIndole acetic acid and indole lactic acid were produced by A. brasilense from tryptophan, and combinations of these substances produced changes in root morphology of pearl millet similar to those produced by inoculated plants.
Abstract: Azospirillum brasilense, a nitrogen-fixing bacterium found in the rhizosphere of various grass species, was investigated to establish the effect on plant growth of growth substances produced by the bacteria. Thin-layer chromatography, high-pressure liquid chromatography, and bioassay were used to separate and identify plant growth substances produced by the bacteria in liquid culture. Indole acetic acid and indole lactic acid were produced by A. brasilense from tryptophan. Indole acetic acid production increased with increasing tryptophan concentration from 1 to 100 μg/ml. Indole acetic acid concentration also increased with the age of the culture until bacteria reached the stationary phase. Shaking favored the production of indole acetic acid, especially in a medium containing nitrogen. A small but biologically significant amount of gibberellin was detected in the culture medium. Also at least three cytokinin-like substances, equivalent to about 0.001 μg of kinetin per ml, were present. The morphology of pearl millet roots changed when plants in solution culture were inoculated. The number of lateral roots was increased, and all lateral roots were densely covered with root hairs. Experiments with pure plant hormones showed that gibberellin causes increased production of lateral roots. Cytokinin stimulated root hair formation, but reduced lateral root production and elongation of the main root. Combinations of indole acetic acid, gibberellin, and kinetin produced changes in root morphology of pearl millet similar to those produced by inoculation with A. brasilense. Images
971 citations
TL;DR: If patients with left‐sided hemispatial neglect bisect lines incorrectly because hemianopia or sensory hemiinattention prevents them from seeing how far the line extends to the left, a strategy that ensures their seeing the left side of the line in their normal field should improve performance.
Abstract: If patients with left-sided hemispatial neglect bisect lines incorrectly because hemianopia or sensory hemiinattention prevents them from seeing how far the line extends to the left, a strategy that ensures their seeing the left side of the line in their normal field should improve performance. If patients have hemispatial hypokinesia, moving the line toward the normal half of body space should improve performance. Six patients with left-sided neglect from right hemisphere infarctions were required to identify a letter at either the right or the left end of a line before bisecting that line. The task was given with the lines placed at either the right, the center, or the left of the body midline. Performance in trials when subjects were required to look to the left before bisecting a line did not differ from when they were required to look right. Performance was significantly better when the line was placed to the right side of the body than to the left. These observations support the hypothesis that patients with hemispatial neglect have hemispatial hypokinesia. An alternative hypothesis is that these subjects had a hemispatial memory defect. Although they saw the left side of the line in their normal field, they were incapable of forming a stable trace and performed as if they did not see the left side of the line.
805 citations
TL;DR: The hypothesis that the right hemisphere dominates activation is supported by results that reduce reaction times of the right hand more than warning stimuli projected to the left hemisphere reduced left hand reaction times.
363 citations
TL;DR: This article examined whether clique-structure in cognitive data (i.e. recall of who one talks to) may be used as a proxy for clique structure in behavioral data (e.g., who one actually talks to).
330 citations
TL;DR: The purpose of this review will be to point out the clinical ramifications of the recent information, and suggest several areas where future investigation might prove fruitful in furthering the understanding of the pathophysiology and management of small intestine bacterial overgrowth.
316 citations
TL;DR: This article found that incomplete sentence context facilitated a subsequent lexical decision only when the test word was a highly likely completion of the sentence, while it inhibited responses to anomalous words, and subjects could not eliminate the inhibition or the facilitation when they were instructed to ignore the implication of each context.
298 citations
TL;DR: The different methods of expressing sugar concentration are here clarified, and the correct methods of converting from one to the other are provided.
Abstract: There are several sources of potential error in calculating the concentration or energy value of floral nectar. Errors resulting from confusing data become substantial with increasing concentration. The different methods of expressing sugar concentration are here clarified, and the correct methods of converting from one to the other are provided. Refractometers in use in field studies usually read on a weight per total weight basis; this is recommended as the mode of statement. The perils of oversimplifying conversions from this mode, as is often done, are pointed out.
278 citations
TL;DR: In this article, the authors proposed a definition of proper efficiency for the case when the domination cone S is a nontrivial, closed convex cone which coincides with Geoffrion's definition when S is the non-negative orthant.
262 citations
TL;DR: It is concluded that riparian soils are anthrosols and that the mechanism of long-term phosphorus loading in lakes is mass transport of soil, which is likely to have dampened population growth at least until Late Classic time.
Abstract: From the first millennium B.C. through the 9th-century A.D. Classic Maya collapse, nonurban populations grew exponentially, doubling every 408 years, in the twin-lake (Yaxha-Sacnab) basin that contained the Classic urban center of Yaxha. Pollen data show that forests were essentially cleared by Early Classic time. Sharply accelerated slopewash and colluviation, amplified in the Yaxha subbasin by urban construction, transferred nutrients plus calcareous, silty clay to both lakes. Except for the urban silt, colluvium appearing as lake sediments has a mean total phosphorus concentration close to that of basin soils. From this fact, from abundance and distribution of soil phosphorus, and from continuing post-Maya influxes (80 to 86 milligrams of phosphorus per square meter each year), which have no other apparent source, we conclude that riparian soils are anthrosols and that the mechanism of long-term phosphorus loading in lakes is mass transport of soil. Per capita deliveries of phosphorus match physiological outputs, approximately 0.5 kilogram of phosphorus per capita per year. Smaller apparent deliveries reflect the nonphosphatic composition of urban silt; larger societal outputs, expressing excess phosphorus from deforestation and from food waste and mortuary disposal, are probable but cannot be evaluated from our data. Eutrophication is not demonstrable and was probably impeded, even in less-impacted lakes, by suspended Maya silt. Environmental strain, the product of accelerating agroengineering demand and sequestering of nutrients in colluvium, developed too slowly to act as a servomechanism, damping population growth, at least until Late Classic time.
251 citations
TL;DR: In this paper, a characterization of Florida lightning return stroke electric and magnetic fields derived from simultaneous measurements of the fields at two separate stations, one station being within 15 km of the lightning, the other at either about 50 or 200 km from the lightning.
Abstract: The paper presents a characterization of Florida lightning return stroke electric and magnetic fields derived from simultaneous measurements of the fields at two separate stations, one station being within 15 km of the lightning, the other at either about 50 or 200 km from the lightning. Also presented are: (1) examples of correlated wave forms, (2) typical first and subsequent stroke wave forms over the distance range 1.0-200 km, and (3) the following statistical data from which the typical wave forms were derived: for electric field, rise time, initial peak value, ramp starting time, ramp slope, value at 170 microsec, ratio of value at 170 microsec to initial peak, zero-crossing time for 50 and 200 km wave forms; for magnetic fields, time of hump following initial peak, ratio of hump value to initial peak value, zero-crossing time for 50 and 200 km wave forms. Return stroke electric and magnetic field characteristics appear to be independent of location in Florida.
245 citations
TL;DR: Sixty-two premature infants less than 2,000 gm birth weight received parenteral nutrition during periods of respiratory distress with feeding intolerance and all five infants who had serial follow-up laboratory studies showed an eventual return of direct bilirubin levels to normal.
Abstract: Sixty-two premature infants less than 2,000 gm birth weight received parenteral nutrition (PN) during periods of respiratory distress with feeding intolerance. Intrahepatic cholestasis (direct bilirubin ≥ 1.5 mg/dl) associated with PN developed in 14 or 23% of these infants. The mean time on PN to onset of cholestasis was 42 days, and the cholestasis persisted as long as the infants continued to receive PN. All five infants who had serial follow-up laboratory studies showed an eventual return of direct bilirubin levels to normal. The direct bilirubin level appeared to be the best clinically available test to monitor for the onset and to follow the resolution of this complication. The very low birth weight infants
TL;DR: In mice, an alcohol diet which is adequate in vitamins and protein results in increased fetal wastage and birth defects, and data indicate that in mice, the incidence of fetal resorptions and congenital malforms increased in a dose-related manner.
Abstract: C57BL/6J mice were fed a liquid diet in which 17, 25, or 30% of the calories were derived from ethanol from the fifth through the tenth day of gestation. Control mice were fed lab chow or pair-fed identical diets, except that sucrose substituted isocalorically for ethanol. At term the fetuses were removed and. following fixation, examined by microdissection. The incidence of fetal resorptions and congenital malformations increased in a dose-related manner. Anomalies included skeletal, neurological, urogenital, and cardiovascular systems. These data indicate that in mice, an alcohol diet which is adequate in vitamins and protein results in increased fetal wastage and birth defects.
TL;DR: Results from the first low-frequency radio receiver to be transported into the Jupiter magnetosphere obtained dramatic new information, both because Voyager was near or in Jupiter's radio emission sources and also because it was outside the relatively dense solar wind plasma of the inner solar system.
Abstract: Results are reported from the first low frequency radio receiver to be transported into the Jupiter magnetosphere. Dramatic new information was obtained both because Voyager was near or in Jupiter's radio emission sources and also because it was outside the relatively dense solar wind plasma of the inner solar system. Extensive radio arcs, from above 30 MHz to about 1 MHz, occurred in patterns correlated with planetary longitude. A newly discovered kilometric wavelength radio source may relate to the plasma torus near Io's orbit. In situ wave resonances near closest approach define an electron density profile along the Voyager trajectory and form the basis for a map of the torus. Studies in progress are outlined briefly.
TL;DR: Periodic movements of the olfactory organs, known as "flicking," temporally enhance the response of the Olfactory receptors of the spiny lobster to changes in stimulus concentration.
Abstract: Periodic movements of the olfactory organs, known as "flicking," temporally enhance the response of the olfactory receptors of the spiny lobster to changes in stimulus concentration. This reflex provides the lobster with a physiological mechanism to compensate for the indiscrete temporal nature of chemical stimuli.
TL;DR: In this paper, the authors used the principle of superposition to derive from fundamentals the widely used shifting approximation that the currentvoltage characteristic of an illuminated solar cell is the dark current-voltage characteristics shifted by the short-circuit photocurrent.
Abstract: The principle of superposition is used to derive from fundamentals the widely used shifting approximation that the current-voltage characteristic of an illuminated solar cell is the dark current-voltage characteristic shifted by the short-circuit photocurrent. Thus the derivation requires the linearity of the boundary-value problems that underlie the electrical characteristics. This focus on linearity defines the conditions that must hold if the shifting approximation is to apply with good accuracy. In this regard, if considerable photocurrent and considerable dark thermal recombination current both occur within the junction space-charge region, then the shifting approximation is invalid. From a rigorous standpoint, it is invalid also if low-injection concentrations of holes and electrons are not maintained throughout the quasi-neutral regions. The presence of sizable series resistance also invalidates the shifting approximation. Methods of analysis are presented to treat these cases for which shifting is not strictly valid. These methods are based on an understanding of the physics of cell operation. This understanding is supported by laboratory experiments and by exact computer solution of the relevant boundary-value problems. For the case of high injection in the base region, the method of analysis employed accurately yields the dependence of the open-circuit voltage on the short-circuit current (or the illumination level).
TL;DR: It is postulate that in some COPD patients these initially transient events may lead to sustained pulmonary hypertension and cor pulmonale and nocturnal oxygen therapy may be indicated in more patients than previously suspected and may prevent the development of cor pulMonale.
TL;DR: In this article, it was shown that with predetermined service times, the total time required to process n dissimilar items through k dissimilar stations does not change when the order of the stations and the orders of the items is reversed.
Abstract: A production line is treated as a series arrangement of k work stations. An unlimited supply of raw production items is available at the first station, and each item passes through all of die stations in sequence. The service time for a single item at station j is assumed to be a random variable with a probability distribution peculiar to that station. In this mode of operation any station will at any time be either busy, or idle, or blocked. A measure of the productivity of such a line is its mean production rate r. It has been conjectured that the production rate remains invariant under reversal of the production line. Line reversal means that every item passes through the stations in the reverse order, that is, beginning with station k and ending with station 1. A general proof of the reversibility property is given. First it is shown that with predetermined service times the total time required to process n dissimilar items through k dissimilar stations does not change when the order of the stations and the order of the items is reversed. Then it is shown for the stochastic case that the order of the items does not affect the production rate.
TL;DR: In this article, a sampling from the null distribution of tables having the same marginal frequencies as the observed table is used for approximating attained significance levels of exact conditional tests, which yields precise approximations for practically any table dimensions and sample size.
Abstract: A procedure is proposed for approximating attained significance levels of exact conditional tests. The procedure utilizes a sampling from the null distribution of tables having the same marginal frequencies as the observed table. Application of the approximation through a computer subroutine yields precise approximations for practically any table dimensions and sample size.
TL;DR: Angus bulls exhibited stable to slight increases in testes size, semen volume and semen quality, suggesting that this breed had reached its most rapid stage of development by 16 months of age, while Hereford bulls showed a decline in testicular size and semenquality suggesting that Hereford Bulls suffered from the environmental stresses of the semitropical summer in Florida.
Abstract: A total of 218 yearling Hereford, Angus, Santa Gertrudis and Brahman bulls was evaluated for semen traits and testieular volume at average ages of 16 and 20 months in April and August, respectively, during 2 successive years. Brahman bulls reached puberty at a later age than bulls of the Santa Gertrudis, Hereford and Angus breeds. Santa Gertrudis bulls had the largest testes with the Brahman having the smallest during this time span. During the summer months, when the bulls were 16 to 20 months of age, testes size, sperm motil i ty and sperm cell concentration of the ejaculate increased markedly in Brahman and Santa Gertrudis bulls. Angus bulls exhibited stable to slight increases in testes size, semen volume and semen quality, suggesting that this breed had reached its most rapid stage of development by 16 months of age. During this same period Hereford bulls showed a decline in testicular size and semen quality suggesting that Hereford bulls suffered from the environmental stresses of the semitropical summer in Florida. Within the Hereford breed, bulls from the lines of Montana origin exhibited a greater decline than those from the line originating in Florida. (
TL;DR: The frequency with which root canals unite should be considered during enlargement and filing procedures, and the possible existence of bifurcated and double canals if root canal therapy should unexplainbly fail should be aware.
Abstract: Morphologic characteristics such as the location of the apical foramens were determined on 400 maxillary first premolars. The determinations of the number of root canals, their type, the ramifications of the main root canal, the location of the apical foramens and transverse anastomosis, and the frequency of apical deltas were made in this study of 400 decalcified maxillary first premolars that had been injected with dye.
TL;DR: Anthers of inbred F44 fertile and cytoplasmic male-sterile corn plants (Zea mays L.) were compared cytologically and it was revealed that mitochondria in ovules remain relatively constant in size and number during gametogenesis and do not undergo degeneration.
Abstract: Anthers of inbred F44 fertile (N) and cytoplasmic male-sterile (T) corn plants (Zea mays L.) were compared cytologically. No differences between fertile and sterile anthers were observed in size and number of mitochondria or plastids until after the start of anther degeneration. A rapid division of mitochondria was observed, however, in the tapetum and sporogenous cells of both fertile and sterile anthers during early growth stages. This rapid increase in mitochondrial numbers per cell (some 20to 40-fold) preceded tapetal breakdown in sterile anthers and did not occur in other anther cells or in plastids. Limited observations on the megagametophyte and nucellus revealed that mitochondria in ovules remain relatively constant in size and number during gametogenesis and do not undergo degeneration. DIFFERENCES in number and size of mitochondria were observed at the various growth stages and in the different tissues during the electron microscope studies that demonstrated early breakdown of tapetal mitochondria in male-sterile corn anthers (Lee, 1976; Warmke and Lee, 1977). Some apparent differences also were noted in plastid size. For these reasons, and because of a possible relationship to male sterility, measurements and counts of these organelles were made as described in the following sections. MATERIALS AND METHODS-Tissue preparation-Anthers of inbred F44 maintainer corn lines (Zea mays L.) and their T cytoplasmic male-sterile counterparts were collected from the field at Gainesville, Florida. The anthers were removed, fixed, embedded, and mounted as reported in earlier ultrastructural studies (Warmke and Lee, 1977). The same procedures for sectioning and staining also were used. In the present studies,
TL;DR: In Florida 21 species of Endogonaceae forming vesicular-arbuscular mycorrhizae are reported, including a new species G. clarus and eight species of the genus Glomus.
Abstract: In Florida 21 species of Endogonaceae forming vesicular-arbuscular mycorrhizae are reported. Eight species of the genus Glomus, including a new species G. clarus, and three species of Sclerocystis ...
TL;DR: The results suggest that the increased grooming observed in the novel environment may be at least partly due to the release of this hormone directly into the cerebral ventricular system.
Abstract: Intact male rats exhibited more grooming in unfamiliar testing chambers than in their home cages. Hypophysectomized rats showed a much reduced increase in grooming in these testing chambers. Intraventricular injections of antiserum to adrenocorticotropic hormone to intact rats decreased the grooming usually observed in the novel situation, whereas a similar injection of control serum did not produce this effect. Peripheral injections of the antiserum did not affect grooming. Since intraventricularly injected adrenocorticotropic hormone induces excessive grooming, these results suggest that the increased grooming observed in the novel environment may be at least partly due to the release of this hormone directly into the cerebral ventricular system.
TL;DR: It is indicated that a manager's experience in a limited region of a nonlinear response function does not enable him to accurately predict decision outcomes or parameters in the unfamiliar regions and that model usage may, in certain situations, actually lead to poorer decisions.
Abstract: Managerial judgment is frequently required to estimate many of the parameters of decision calculus models and the quality of these judgmental inputs may substantially affect model-based decisions. This paper suggests that if model builders are to rely upon managerial judgments in building models, research should be directed at understanding when managerial judgments will be valid and the types of biases that might be expected. A quasi-experimental design is used to explore managers' abilities to estimate the parameters of a decision-calculus model ADBUDG and to examine the value of this model in decision-making. The results are consistent with previous evidence of the existence of biases in human judgment. More specifically, they indicate that a manager's experience in a limited region of a nonlinear response function does not enable him to accurately predict decision outcomes or parameters in the unfamiliar regions and that model usage may, in certain situations, actually lead to poorer decisions.
TL;DR: In this article, the authors report on the dynamics of the standard penetration test (SPT) as determined from a study involving hammer impact and wave mechanics theory, field measurements of dynamic behavior during SPT, and computer simulations using the wave equation as developed for computer studies of pile driving.
Abstract: The writers report on the dynamics of the standard penetration test (SPT) as determined from a study involving hammer impact and wave mechanics theory, field measurements of dynamic behavior during SPT, and computer simulations using the wave equation as developed for computer studies of pile driving. The field data match well with the theory presented and the simulations provided further insight into the details of SPT sampler penetration. The work includes methods for determining the amount of hammer enery reaching the sampler, and for determining the energy lost to the sampler. The writers conclude that blow count varies inversely with the wave energy reaching the sampler, and that the SPT represents a form of in situ, undrained, cyclic load test and offers a method for site-specific determinations of the J damping coefficients in wave equation analyses of pile driving.
TL;DR: These data both expand the catalog of species for which paternal behavior has been described and extend previous observations in several species, however, they provide little support for hypotheses that such behavior in the laboratory either is indicative of paternalbehavior in the field or is a correlate of monogamous breeding systems, certainty of paternity, or adoption of a K-strategy in nature.
TL;DR: The ability of AAV to inhibit adenovirus DNA replication may indicate a common feature in an early step of DNA replication in spite of the apparent overall differences in the mechanism of initiation.
Abstract: Publisher Summary The adeno-associated viruses (AAV) are defective parvoviruses that require coinfection with an adenovirus for a productive infection. In many ways AAV is a unique virus because of its special properties of dependence on adenovirus for replication and the fact that both plus and minus strands are encapsidated. It is a parvovirus but differs from the autonomous parvoviruses in its defectiveness, the encapsidation of both DNA strands, and the existence of an inverted terminal nucleotide sequence repetition in its genome. The ability of AAV to inhibit adenovirus DNA replication may indicate a common feature in an early step of DNA replication in spite of the apparent overall differences in the mechanism of initiation. The ability of various adenovirus variants to help AAV DNA replication may be used to screen for new genes involved in adenovirus DNA replication. AAV may inhibit SV40 DNA replication but is not helped by SV40 coinfection at the level of DNA. AAV inhibition of adenovirus and herpes simplex virus oncogenicity is another interesting phenomenon. There are no data concerning the level at which the interference takes place. The only suggestive data in this regard come from the observation that AAV does not have an effect on adenovirus oncogenicity in newborn Syrian hamsters. AAV can establish a latent infection in the normal host in the absence of concomitant adenovirus infection.
TL;DR: Both in‐field recurrence and generalized relapse were closely related to the number of anatomical sites involved, and treatment programs need to consider tumor size, particularly in the mediastinum, and thenumber of sites involved.
Abstract: A total of 57 patients with Hodgkin's disease limited to above the diaphragm (Stages I and II, A and B) were treated with radiation therapy alone at the University of Florida between 1964 and 1974. Staging laparotomy was done on 24 patients (42%). A total of 16 patients have relapsed, 4 within the treatment fields, 3 marginally, and 9 as extensions. Analysis of dose vs. size showed no in-field failure with disease less than 6 cm in size, with a range of doses. Massive disease continued to recur occasionally, even with higher doses. Most of the massive disease was mediastinal or hilar; the risk of lung or pleural involvement as determined by x-ray and/or biopsy showed a dramatic increase with size of mediastinal/hilar disease. Only 2 (5%) of 43 patients with mediastinal disease less than 6 cm in size had lung or pleural involvement, compared with 10 (71%) of 14 patients with disease greater than 6 cm in size. Both in-field recurrence and generalized relapse were closely related to the number of anatomical sites involved. Treatment programs need to consider tumor size, particularly in the mediastinum, and the number of sites involved.