Showing papers by "University of Florida published in 1989"

Fundamentals of Database Systems

Abstract: From the Publisher: Fundamentals of Database Systems combines clear explanations of theory and design, broad coverage of models and real systems, and excellent examples with up-to-date introductions to modern database technologies. This edition is completely revised and updated, and reflects the latest trends in technological and application development. Professors Elmasri and Navathe focus on the relational model and include coverage of recent object-oriented developments. They also address advanced modeling and system enhancements in the areas of active databases, temporal and spatial databases, and multimedia information systems. This edition also surveys the latest application areas of data warehousing, data mining, web databases, digital libraries, GIS, and genome databases. New to the Third Edition Reorganized material on data modeling to clearly separate entity relationship modeling, extended entity relationship modeling, and object-oriented modeling Expanded coverage of the object-oriented and object/relational approach to data management, including ODMG and SQL3 Uses examples from real database systems including OracleTM and Microsoft AccessAE Includes discussion of decision support applications of data warehousing and data mining, as well as emerging technologies of web databases, multimedia, and mobile databases Covers advanced modeling in the areas of active, temporal, and spatial databases Provides coverage of issues of physical database tuning Discusses current database application areas of GIS, genome, and digital libraries

Opportunities and Responsibilities in Pharmaceutical Care.

Abstract: Pharmacy's opportunity to mature as a profession by accepting its social responsibility to reduce preventable drug-related morbidity and mortality is explored. Pharmacy has shed the apothecary role but has not yet been restored to its erst-while importance in medical care. It is not enough to dispense the correct drug or to provide sophisticated pharmaceutical services; nor will it be sufficient to devise new technical functions. Pharmacists and their institutions must stop looking inward and start redirecting their energies to the greater social good. Some 12,000 deaths and 15,000 hospitalizations due to adverse drug reactions (ADRs) were reported to the FDA in 1987, and many went unreported. Drug-related morbidity and mortality are often preventable, and pharmaceutical services can reduce the number of ADRs, the length of hospital stays, and the cost of care. Pharmacists must abandon factionalism and adopt patient-centered pharmaceutical care as their philosophy of practice. Changing the focus of practice from products and biological systems to ensuring the best drug therapy and patient safety will raise pharmacy's level of responsibility and require philosophical, organizational, and functional changes. It will be necessary to set new practice standards, establish cooperative relationships with other health-care professions, and determine strategies for marketing pharmaceutical care. Pharmacy's reprofessionalization will be completed only when all pharmacists accept their social mandate to ensure the safe and effective drug therapy of the individual patient.

Determinants of Continuity in Conventional Industrial Channel Dyads

Abstract: Recently, increasing attention has been paid to the question of how to build stable, long-term relationships between manufacturers and members of conventional channels. This descriptive field study concerns a basic requirement for building long-term relationships, which is the expectation by a marketing intermediary that the relationship will last. Hypotheses about the continuity of relationships are developed from the literature on social exchange, bargaining, and negotiation. These hypotheses are framed as a simultaneous equation system, which is estimated via three-stage least squares on a sample of 690 relationships dyads involving manufacturers and their independent sales agents manufacturers' representatives. Results substantially support the model, highlighting the importance of interpersonal relationships in insuring the continuity of the dyad.

An Empirical Examination of the Structural Antecedents of Attitude toward the Ad in an Advertising Pretesting Context

Abstract: Recent research has identified attitude toward the ad (AAd) as an important construct mediating the effects of advertising on brand attitude and purchase intention. To date, however, little attenti...

Treatment of chronic hepatitis C with recombinant interferon alfa. A multicenter randomized, controlled trial.

Abstract: Chronic hepatitis C (non-A, non-B hepatitis) is a common and often progressive viral liver disease. To assess the efficacy of therapy with the antiviral agent interferon alfa, we randomly ...

Effects of Forest Fragmentation on Dung and Carrion Beetle Communities in Central Amazonia

Abstract: This study, one of the first to document the effects of forest fragmentation on insects in the tropics, showed that dung and carrion beetle communities in 1-ha and 10-ha forest fragments differed from those in contiguous forest, even though the fragments had been isolated by <350 m for an ecologically short time (2-6 yr). During 288 pitfall trap days at the Minimum Critical Size of Ecosystems study site 80 km north of Manaus, Brazil, I captured 55 species in 15 genera. Trap days were divided equally between three 1-ha, three 10-ha, three clear-cut, and three contiguous forest areas. Pitfall samples from clear-cut areas separating forest fragments from intact forest in- dicated that beetles rarely moved from intact forest into fragments. The apparent barrier imposed by clearcuts diminished with the invasion of second growth. Except for the four species in the genus Glaphyrocanthon, all species were found more frequently in forested areas than in clearcuts. Glaphyrocanthon constituted 97% of the 717 individuals captured in clearcuts and was never captured in contiguous forest or 10-ha fragments. Forest fragments had fewer species, sparser populations, and smaller beetles than com- parable intact forest areas. The changes in dung and carrion beetle communities help explain the low rates at which dung decomposed in 1-ha fragments. Thus, forest fragmentation not only changes the dung and carrion beetle fauna; its effects ramify through other related community and ecosystem processes, as well.

Scheduling precedence graphs in systems with interprocessor communication times

Abstract: The problem of nonpreemptively scheduling a set of m partially ordered tasks on n identical processors subject to interprocessor communication delays is studied in an effort to minimize the makespan. A new heuristic, called Earliest Task First (ETF), is designed and analyzed. It is shown that the makespan $\omega _{{\text{ETF}}} $ generated by ETF always satisfies $\omega _{{\text{ETF}}} \leqq ({{2 - 1} / n})\omega _{{\text{opt}}}^{(i)} + C$, where $\omega _{{\text{opt}}}^{(i)} $ is the optimal makespan without considering communication delays and C is the communication requirements over some immediate predecessor-immediate successor pairs along one chain. An algorithm is also provided to calculate C. The time complexity of Algorithm ETF is $O(nm^2 )$.

Sorption nonideality during organic contaminant transport in porous media

Abstract: In modeling subsurface contaminant transport, sorption is often simplified by assuming instantaneous equilibrium, isotherm linearity, and sorption‐desorption singularity. Data exhibiting behavior that deviates from that predicted by this simple model have been reported, challenging the validity of these assumptions. This nonideal sorptive behavior has been attributed to several different factors, including kinetic sorption reactions, diffusive mass transfer resistances, isotherm nonlinearity, and sorption‐desorption nonsingularity. These factors are examined and their relative impact on contaminant transport is evaluated. For hydrophobic organic compounds, physical nonequilibrium (i.e., rate‐limited mass‐transfer in aggregated or layered systems) and intraorganic matter diffusion (rate‐limited diffusion within the sorbent organic matter matrix) are probably the predominant factors causing nonideality. The relative importance of these factors is scale‐dependent. For smaller scale systems, mass‐transfer lim...

Response surface methodology: 1966–1988

Abstract: Response sarfxe methodology (RSM) is a collection of tools developed in the 1950s for the purpose of determining optimum operating conditions in applications in the chemical industry. This article reviews the progrrss of RSM in the general areas of experimental design and analysis and indicates how its role has been affected by advanccs in other fields of applied statistics. Current areas of research in RSM are highlighted. and areas for future research are discussed.

Nitrification‐denitrification at the plant root‐sediment interface in wetlands

Abstract: Oxygen transport through the air spaces (aerenchyma tissue) of the stem and roots of aquatic macrophytes into the root zone supports nitrification of NH,+, with the NOJ- formed diffusing into the adjacent anaerobic zone where it undergoes #denitrification. To test this hypothesis, we conducted a growth chamber study to determine the transformation of applied 15NH,+-N to r5N, in the root zone of three aquatic macrophytes: rice (Oryza sativa L.), pickerel weed (Pontecferia cordata L.), and soft rush (Juncus e&us L.). Detection of gaseous 15N, in the air above the floodwater of the soil column with aquatic plants provided direct evidence of nitrification-dcnitrification in the root zone, while such losses were not measurable for soil columns without plants. Air spaces in aquatic plants can also function as conduits for denitrified gases from anaerobic sediments to the atmosphere. Maximal 15N, flux due to this process was 102, 113, and 122 mg N m-2 d-l for soft rush, rice, and pickerel weed. This N loss mechanism has important agronomic and ecological consequences.

The pharmacology of dichloroacetate.

Abstract: Dichloroacetate (DCA) exerts multiple effects on pathways of intermediary metabolism. It stimulates peripheral glucose utilization and inhibits gluconeogeneis, thereby reducing hyperglycemia in animals and humans with diabetes mellitus. It inhibits lipogenesis and cholesterolgenesis, thereby decreasing circulating lipid and lipoprotein levels in short-term studies in patients with acquired or hereditary disorders of lipoprotein metabolism. By stimulating the activity of pyruvate dehydrogenase, DCA facilitates oxidation of lactate and decreases morbidity in acquired and congenital forms of lactic acidosis. The drug improves cardiac output and left ventricular mechanical efficiency under conditions of myocardial ischemia or failure, probably by facilitating myocardial metabolism of carbohydrate and lactate as opposed to fat. DCA may also enhance regional lactate removal and restoration of brain function in experimental states of cerebral ischemia. DCA appears to inhibit its own metabolism, which may influence the duration of its pharmacologic actions and lead to toxicity. DCA can cause a reversible peripheral neuropathy that may be related to thiamine deficiency and may be ameliorated or prevented with thiamine supplementation. Other toxic effects of DCA may be species-specific and reflect marked interspecies variation in pharmacokinetics. Despite its potential toxicity and limited clinical experience, DCA and its derivatives may prove to be useful in probing regulatory aspects of intermediary metabolism and in the acute or chronic treatment of several metabolic disorders.

A theory of attributed equivalence in databases with application to schema integration

Abstract: The authors present a common foundation for integrating pairs of entity sets, pairs of relationship sets, and an entity set with a relationship set. This common foundation is based on the basic principle of integrating attributes. Any pair of objects whose identifying attributes can be integrated can themselves be integrated. Several definitions of attribute equivalence are presented. These definitions can be used to specify the exact nature of the relationship between a pair of attributes. Based on these definitions, several strategies for attribute integration are presented and evaluated. >

Genetic and structural characterization of the avirulence gene avrBs3 from Xanthomonas campestris pv. vesicatoria

Abstract: The avirulence gene avrBs3 from Xanthomonas campestris pv. vesicatoria was cloned and found to be localized on a self-transmissable plasmid. Genetic analysis of an avrBs3 insertion mutation revealed that avrBs3 constitutes a single locus, specifying the resistant phenotype on pepper plants. Southern blot experiments showed that no DNA sequences homologous to avrBs3 were present in other races of X. c. pv. vesicatoria, which are unable to induce a hypersensitive reaction on ECW-30R. However, the DNA of several different pathovars of X. campestris hybridized to the avrBs3 probe. A deletion analysis defined a region of 3.6–3.7 kb essential for avrBs3 activity. The nucleotide sequence of this region was determined. A 3561 nucleotide open reading frame (ORF1), encoding a 125000 dalton protein, was found in the 3.7 kb region that was sufficient for avrBs3 activity. A second long ORF (2351 nucleotides) was identified on the other strand. A remarkable feature of both ORFs is the presence of 17 direct repeats of 102 bp which share 91%–100% homology with each other.

Long-term effects of ovariectomy and aging on the rat skeleton

Abstract: The long-term skeletal effects of ovariectomy and aging were studied in female Sprague-Dawley rats sacrificed at 270, 370, and 540 days after bilateral ovariectomy (OVX) or sham surgery at 90 days of age. The proximal tibia was processed undecalcified for quantitative bone histomorphometry. For continuity, data from these late time points were combined with previously published data from earlier time points (0-180 days). A biphasic pattern of cancellous bone loss was detected in the proximal tibial metaphysis of OVX rats. An initial, rapid phase of bone loss out to 100 days was followed by an intermediate period of relative stabilization of cancellous bone volume at the markedly osteopenic level of 5-7%. After 270 days, a slow phase of bone loss occurred during which cancellous bone volume declined to 1-2%. Both the initial, rapid phase and the late, slow phase of bone loss in OVX rats were associated with increased bone turnover. In control rats, cancellous bone volume remained constant at 25-30% out to 270 days (12 months of age), then decreased to approximately 10% by 540 days (21 months of age). This age-related bone loss was also associated with increased bone turnover. It is interesting to note that the proximal tibial growth plates were closed in approximately a quarter of the control rats by 15-21 months of age. Our data indicate that a slow rate of bone loss and increased bone turnover persist in OVX rats during the later stages of estrogen deficiency. Therefore, the development of osteopenia is coincident with increased bone turnover in OVX rats as well as in aged, control rats.

The molecular mechanisms of copper and silver ion disinfection of bacteria and viruses

Abstract: Disinfection due to copper or silver ions may result from action at the cell or capsid protein surface or on the nucleic acid of cells or viruses. Metals may alter enzyme structure and function or facilitate hydrolysis or nucleophilic displacement. The means by which cells may reduce the toxic effect of metal ions include: biomethylation, complexation with metallothionen, development of efflux pumps, the binding of metal ions to cell surfaces, and the removal of metal ions by precipitation. The phenomenon of “multiplicity of reactivation” may reduce the effect of a disinfectant on a virus by allowing a clump of partially inactivated viruses to produce a productive infection in a susceptible cell. Conditions which may affect metal ion‐biomolecule interaction include: pH, ionic strength, temperature, dissolved oxygen, presence of interfering substances or light, the chemical form and valency of the metal ion, and the condition of the microorganisms.

Salesforce Compensation: An Empirical Investigation of Factors Related to Use of Salary versus Incentive Compensation:

Abstract: The transaction cost analysis framework is integrated with prescriptions from the sales management literature to develop a model that indicates the role of salary in a sales compensation plan for i...

Role of histidine 64 in the catalytic mechanism of human carbonic anhydrase II studied with a site-specific mutant

Abstract: To test the hypothesis that histidine 64 in the active site of human carbonic anhydrase II functions as a proton-transfer group in the catalysis of CO2 hydration, we have studied a site-specific mutant having histidine 64 replaced by alanine, which cannot transfer protons. The steady-state kinetics of CO2 hydration has been measured as well as the exchange of 18O between CO2 and water at chemical equilibrium. The results show that the rate of exchange between CO2 and HCO3- at chemical equilibrium is essentially unaffected by the amino acid substitution at pH greater than 7.0 and slightly decreased in the mutant at pH less than 7.0 (by a factor of 2 at pH 6.0). However, in the absence of buffer the rate of release from the active site of water bearing substrate oxygen is smaller by as much as 20-fold for the mutant as compared to unmodified enzyme. Furthermore, in the unmodified enzyme water release is inhibited by micromolar concentrations of Cu2+ ions, but no such inhibition is observed with the alanine 64 variant. These results suggest that the mutation has specifically affected the rate of proton transfer between the active site and the reaction medium. This kinetic defect in the mutant can be overcome by increasing the concentration of certain buffers, such as imidazole and 1-methylimidazole, but not by others buffers, such as MOPS or HEPES. Similarly, the maximal rate of CO2 hydration at steady state catalyzed by the alanine 64 variant is very low in the presence of MOPS or TAPS buffers but considerably higher in the presence of imidazole derivatives.(ABSTRACT TRUNCATED AT 250 WORDS)

Ecology and physiology of hibernation and overwintering among freshwater fishes, turtles, and snakes

Abstract: Summary 1. Freshwater fishes are the most northerly of freshwater ectotherms, followed by frogs. North American freshwater snakes, turtles, and salamanders do not range farther north than southernmost Canada. 2. Freezing and desiccation are the main challenges during terrestrial hibernation of ectotherms. Oxygen depletion, water balance, and ionic balance are the major problems for air breathing ectotherms that hibernate underwater. 3. The importance of accumulation of energy stores for overwintering among fishes depends upon the length and severity of the winters, whether or not there is springtime reproduction, body size, latitude, and the availability and use of food during overwintering. 4. Fishes can decrease energy demands during the winter by reductions in activity, metabolic depression, and entrance in semi-torpidity. 5. Adaptations for coping with hypoxia and anoxia among overwintering freshwater fishes may include metabolic depression, a decrease in blood O2 affinity, microhabitat selection, air breathing, short-distance migration, biochemical modifications aimed at adjusting glycolytic rates, and alcoholic fermentation. 6. Freshwater turtles have a worldwide northern limit of approximately 50° N, which means that some species spend about half of their lives hibernating. 7. Aquatic turtles normally hibernate underwater, although occasionally they hibernate on land. In water they usually hibernate in a hypoxic or anoxic (mud) environment and in relatively shallow water. Wintertime movements of unknown frequency occur in some species. 8. The hatchlings of many turtle species can overwinter in the nest. Among northern species this behaviour is most common among painted turtles, whose hatchlings can withstand freezing. 9. Mortality among adult turtles is probably highest during the hibernation cycle. 10. Temperature appears to the most important cue for entry and exit from hibernation among freshwater turtles. 11. Little is known of the energetics of overwintering turtles. Energy stores for overwintering may be more important at lower latitudes than at higher ones, due to the higher metabolic rates of overwintering, but non-feeding, southern turtles. 12. The ability of turtles to tolerate submergence is a function of temperature, degree of water oxygenation, latitude of origin, efficacy of extrapulmonary respiratory pathways, and metabolic rate. 13. For turtles that hibernate in an anoxic hibernaculum, and for those without sufficient extrapulmonary uptake of O2 to allow metabolism to be completely aerobic, the most important physiological perturbation is an acidosis developed from a continuing production of lactate. If sufficient O2 can be obtained, the most likely factors limiting hibernation time are water balance and ion balance. 14. Mechanisms of turtles for coping with acidosis include metabolic depression, integumental CO2 loss, bicarbonate buffering, and changes in ion concentrations that minimize the decrease in SID (strong ion difference). The most important among the latter are a decrease in plasma [Cl-] and large increases in plasma calcium and magnesium. 15. Turtles are unique among reptiles in their ability to maintain both cardiovascular and nervous system function during prolonged anoxia. 16. Turtles gain weight from water uptake during submerged hibernation, but apparently maintain some kidney function; however, osmoregulation is one of the least known areas of the physiology of hibernation. 17. Recovery of turtles upon emergence commences with a rapid hyperventilatory compensation of pH, followed by a slower adjustment of ion levels. Basking speeds recovery greatly. 18. While hibernation of turtles in the northern parts of their ranges is most likely very stressful physiologically, northern range limits are more likely to be determined by reproductive restraints than by the rigors of extended hibernation. 19. The superior ability of turtles to tolerate anoxia may be more the result of an annual hibernation than of their diving habits during active periods of the year. 20. Freshwater snakes usually hibernate on land. However, they appear to be capable of aquatic hibernation and may not do so because of the risk of death from anoxia. 21. Some species of terrestrial snakes are known to hibernate underwater, and are able to do so in the laboratory for months. In the field, this behaviour is considered opportunistic, as there is no evidence to suggest that any snakes can tolerate extended anoxia.

Molecular Analysis of viviparous-1: An Abscisic Acid-Insensitive Mutant of Maize.

Abstract: The viviparous-1 (vp1) gene in maize controls multiple developmental responses associated with the maturation phase of seed formation. Most notably, mutant embryos have reduced sensitivity to the hormone abscisic acid, resulting in precocious germination, and blocked anthocyanin synthesis in aleurone and embryo tissues. The Vp1 locus was cloned by transposon tagging, using the Robertson's Mutator element present in the vp1-mum1 mutant allele. Detection of DNA rearrangements in several spontaneous and transposable element-induced mutant vp1 alleles, including a partial deletion of the locus, confirmed the identity of the clone. The Vp1 gene encodes a 2500-nucleotide mRNA that is expressed specifically in embryo and endosperm tissues of the developing seed. This transcript is absent in seed tissues of vp1 mutant stocks. Expression of C1, a regulatory gene for the anthocyanin pathway, is selectively blocked at the mRNA level in vp1 mutant seed tissues, indicating the Vp1 may control the anthocyanin pathway by regulating C1. We suggest that the Vp1 gene product functions to potentiate multiple signal transduction pathways in specific seed tissues.

Neutrophil function in ischemic heart disease.

Abstract: Neutrophils contribute to the healing of and scar formation in myocardium after ischemic injury. Many recent studies indicate that neutrophils may be involved in the genesis and propagation of myocardial ischemia. To characterize neutrophil function in ischemic heart disease, neutrophil chemotaxis, leukotriene B4 (LTB4) generation, and elastase release in plasma were measured in 20 patients with stable angina, 17 patients with unstable angina or acute myocardial infarction (AMI), and 20 age-matched control subjects. Neutrophils from patients with stable angina exhibited markedly increased chemotactic activity and LTB4 generation as compared with the age-matched control subjects (p less than 0.01). Neutrophils of nine of 17 patients with unstable angina or AMI clumped spontaneously ex vivo and exhibited marked pseudopod formation and granule extrusion on electron microscopy. Subsequent chemotactic activity and LTB4 generation by neutrophils from these patients was less than in patients with stable angina, suggesting previous in vivo activation. Plasma levels of peptide B beta, a product of fibrin degradation by human neutrophil elastase, were approximately 15-fold higher (p less than 0.001) in patients with unstable angina or AMI (588 +/- 171 pmol/l, mean +/- SEM) compared with those in patients with stable angina (37 +/- 25 pmol/l) or control subjects (40 +/- 22 pmol/l), confirming intense in vivo neutrophil activation. Our study shows enhanced neutrophil function in patients with ischemic heart disease. The increased neutrophil chemotactic activity and LTB4 generation may be markers of stable angina pectoris. Intense neutrophil activation in unstable angina or AMI, as manifested by morphologic changes in neutrophils and elastase release, may relate to ongoing in vivo cellular activation.

Early stages of calcium-phosphate layer formation in bioglasses

Abstract: Bioglasses with and without fluoride have been shown to be surface-active biomaterials. In the present in-vitro work, apatite formation on the surface of fluoride Bioglass® and non-fluoride Bioglass® is studied at the early stages of reaction. Fourier transform infrared reflection spectroscopy (FT-IRRS) analysis is used to monitor apatite-layer and silica-rich-layer formation on Bioglass® surfaces after they are reacted in a tris-buffer solution. Ion concentrations in the reacted solutions, and elemental depth profiles are obtained by induced coupled plasma atomic emission spectrometry (ICP) and Auger electron spectroscopy (AES) respectively. At a very early stage of reaction, the formation of SiO bonds with one non-bridging oxygen and SiOSi bridging bonds produced a silica-rich layer. Simultaneously, an amorphous calcium-phosphate layer forms and crystallizes after 2 h of reaction. Fluorine ions are incorporated within the apatite crystals in the fluoride Bioglass®. The release rates for Na and Ca ions are higher for fluoride Bioglass®. The formation of HPO 4 2− ions was found in fluoride Bioglass® reaction layers, but not in the non-fluorid Bioglass® when reacted up to 120 h.

Effects of incomplete pulmonary gas exchange on VO2 max

Abstract: Recent evidence suggests that heavy exercise may lower the percentage of O2 bound to hemoglobin (%SaO2) by greater than or equal to 5% below resting values in some highly trained endurance athletes. We tested the hypothesis that pulmonary gas exchange limitations may restrict VO2max in highly trained athletes who exhibit exercise-induced hypoxemia. Twenty healthy male volunteers were divided into two groups according to their physical fitness status and the demonstration of exercise-induced reductions in %SaO2 less than or equal to 92%: 1) trained (T), mean VO2max = 56.5 ml.kg-1.min-1 (n = 13) and 2) highly trained (HT) with maximal exercise %SaO2 less than or equal to 92%, mean VO2max = 70.1 ml.kg-1.min-1 (n = 7). Subjects performed two incremental cycle ergometer exercise tests to determine VO2max at sea level under normoxic (21% O2) and mild hyperoxic conditions (26% O2). Mean %SaO2 during maximal exercise was significantly higher (P less than 0.05) during hyperoxia compared with normoxia in both the T group (94.1 vs. 96.1%) and the HT group (90.6 vs. 95.9%). Mean VO2max was significantly elevated (P less than 0.05) during hyperoxia compared with normoxia in the HT group (74.7 vs. 70.1 ml.kg-1.min-1). In contrast, in the T group, no mean difference (P less than 0.05) existed between treatments in VO2max (56.5 vs. 57.1 ml.kg-1.min-1). These data suggest that pulmonary gas exchange may contribute significantly to the limitation of VO2max in highly trained athletes who exhibit exercise-induced reductions in %SaO2 at sea level.(ABSTRACT TRUNCATED AT 250 WORDS)