Showing papers by "University of Kentucky published in 1992"

beta-Amyloid peptides destabilize calcium homeostasis and render human cortical neurons vulnerable to excitotoxicity

Abstract: In Alzheimer's disease (AD), abnormal accumulations of beta-amyloid are present in the brain and degenerating neurons exhibit cytoskeletal aberrations (neurofibrillary tangles). Roles for beta-amyloid in the neuronal degeneration of AD have been suggested based on recent data obtained in rodent studies demonstrating neurotoxic actions of beta- amyloid. However, the cellular mechanism of action of beta-amyloid is unknown, and there is no direct information concerning the biological activity of beta-amyloid in human neurons. We now report on experiments in human cerebral cortical cell cultures that tested the hypothesis that beta-amyloid can destabilize neuronal calcium regulation and render neurons more vulnerable to environmental stimuli that elevate intracellular calcium levels. Synthetic beta-amyloid peptides (beta APs) corresponding to amino acids 1–38 or 25–35 of the beta-amyloid protein enhanced glutamate neurotoxicity in cortical cultures, while a peptide with a scrambled sequence was without effect. beta APs alone had no effect on neuronal survival during a 4 d exposure period. beta APs enhanced both kainate and NMDA neurotoxicity, indicating that the effect was not specific for a particular subtype of glutamate receptor. The effects of beta APs on excitatory amino acid (EAA)-induced neuronal degeneration were concentration dependent and required prolonged (days) exposures. The beta APs also rendered neurons more vulnerable to calcium ionophore neurotoxicity, indicating that beta APs compromised the ability of the neurons to reduce intracellular calcium levels to normal limits. Direct measurements of intracellular calcium levels demonstrated that beta APs elevated rest levels of calcium and enhanced calcium responses to EAAs and calcium ionophore. The neurotoxicity caused by EAAs and potentiated by beta APs was dependent upon calcium influx since it did not occur in calcium-deficient culture medium. Finally, the beta APs made neurons more vulnerable to neurofibrillary tangle-like antigenic changes induced by EAAs or calcium ionophore (i.e., increased staining with tau and ubiquitin antibodies). Taken together, these data suggest that beta-amyloid destabilizes neuronal calcium homeostasis and thereby renders neurons more vulnerable to environmental insults.

Relative neighborhood graphs and their relatives

Abstract: Results of neighborhood graphs are surveyed. Properties, bounds on the size, algorithms, and variants of the neighborhood graphs are discussed. Numerous applications including computational morphology, spatial analysis, pattern classification, and databases for computer vision are described. >

Developing Customer Orientation among Service Employees

Abstract: A conceptual framework is proposed that considers the customer orientation of service employees and its relationship with their perceived level of organizational socialization and perceptions of the organizational climate for service, motivational effort and direction, and organizational commitment. Structural equation modeling techniques are applied to data collected from employees in the financial services industry to test the framework. The results of this study indicate higher levels of customer orientation result from favorable perceptions of the organizational climate for service and higher levels of motivational direction and organizational commitment. In addition, organizational socialization was found to have a positive impact on perceptions of climate, levels of motivation, and organizational commitment.

Overview of multidatabase transaction management

Abstract: A multidatabase system (MDBS) is a facility that allows users access to data located in multiple autonomous database management systems (DBMSs). In such a system, global transactions are executed under the control of the MDBS. Independently, local transactions are executed under the control of the local DBMSs. Each local DBMS integrated by the MDBS may employ a different transaction management scheme. In addition, each local DBMS has complete control over all transactions (global and local) executing at its site, including the ability to abort at any point any of the transactions executing at its site. Typically, no design or internal DBMS structure changes are allowed in order to accommodate the MDBS. Furthermore, the local DBMSs may not be aware of each other and, as a consequence, cannot coordinate their actions. Thus, traditional techniques for ensuring transaction atomicity and consistency in homogeneous distributed database systems may not be appropriate for an MDBS environment. The objective of this article is to provide a brief review of the most current work in the area of multidatabase transaction management. We first define the problem and argue that the multidatabase research will become increasingly important in the coming years. We then outline basic research issues in multidatabase transaction management and review recent results in the area. We conclude with a discussion of open problems and practical implications of this research.

Free radical damage to protein and DNA : mechanisms involved and relevant observations on brain undergoing oxidative stress

Abstract: Iron mediates damage to proteins and DNA. The mechanisms of damage not only involve iron but also oxygen free radical intermediates. Oxidative damage to DNA causes not only strand breaks, but also formation of specific base adducts, such as 8-hydroxy-2'-deoxyguanosine. Oxidative damage also inactivates certain enzymes such as glutamine synthetase. Novel methods of assessing oxidative damage to tissue, including quantitation of salicylate hydroxylation as an index of hydroxyl free radical flux as well as specific lesions to proteins and DNA, have yielded results that clearly show that ischemia/reperfusion injury to mongolian gerbil brain involves oxidatively damaging events. Aging in gerbil as well as human brain is also associated with increased oxidative damage. Recent novel observations have shown that the spin-trapping agent phenyl alpha-tert-butylnitrone (PBN) offers protection in gerbil brain during ischemia/reperfusion injury. We also show that oxidative damage to brain during aging is decreased by chronic administration of PBN. The mechanism of action of PBN may be related to its trapping of specific free radicals, which triggers a cascade of oxidative events that eventually lead to tissue injury.

Learning to Teach Hard Mathematics: Do Novice Teachers and Their Instructors Give Up Too Easily?

Abstract: This article analyzes from several vantage points a classroom lesson in which a student teacher was unsuccessful in providing a conceptually based justification for the standard division-offractions algorithm. We attempt to understand why the lesson failed, what it reveals about learning to teach, and what the implications are for mathematics teacher education. We focus on (a) the student teacher's beliefs about good mathematics teaching, her knowledge related to division of fractions, and her beliefs about learning to teach; and (b) the treatment of division of fractions in the mathematics methods course she took. The student teacher's conception of good mathematics teaching included components compatible with current views of effective mathematics teaching. However, these beliefs are difficult to achieve without a stronger conceptual knowledge base and a greater commitment to use available resources and to engage in hard thinking than she possessed. Further, the mathematics methods course did not require the student teacher to reconsider her knowledge base, to confront the contradictions between her knowledge base and at least some of her beliefs, or to reassess her beliefs about how she would learn to teach. These findings suggest that mathematics teacher education programs should reconsider how they provide subject matter knowledge and opportunities to teach it, and whether and how they challenge student teachers' existing beliefs.

A Selectivity Model of Household Food Marketing Behavior in Sub-Saharan Africa

Abstract: The agricultural household's discrete decision of whether to participate in coarse grain markets is separated here from the continuous decision of how much to sell or buy, conditional on participation. Failure to participate in markets results from high fixed transactions costs. A selectivity model endogenously switches households into alternative market participation states, correcting for bias caused by the exclusion of unobservable variables affecting both discrete and continuous decisions. Improved market information increases the probability of participation by sellers, while access to cereals-processing technology increases quantities transacted by both sellers and buyers, conditional on participation.

Sustained release drug delivery devices

Abstract: A method and device for treating a mammalian organism to obtain a desired local or systemic physiological or pharmacological effect is provided. The method includes administering a sustained release drug delivery system to a mammalian organism in need of such treatment at an area wherein release of an effective agent is desired and allowing the effective agent to pass through the device in a controlled manner. The device includes an inner core or reservoir comprising the effective agent; a first coating layer, which is permeable to the passage of the effective agent; a second coating layer, which is essentially impermeable to the passage of the effective agent; and a third coating layer, which is permeable to the passage of the effective agent. The first coating layer covers at least a portion of the inner core. The second coating layer covers at least a portion of the first coating layer and inner core; however, at least a small portion of the first coating layer or inner core is not coated with the second coating layer. The second coating layer includes an impermeable film and at least one impermeable disc. The third coating layer essentially completely covers the second coating layer and the uncoated portion of the first coating layer or inner core.

The lipophosphoglycan of Leishmania parasites

Abstract: Protozoan parasites of the genus Leishmania have the remarkable ability to avoid destruction in the hostile environments they encounter throughout their life cycle. The molecular details of how these pathogens persevere with impunity under harsh conditions are beginning to be understood. The fact that Leishmania parasites have adapted to not only survive, but to proliferate probably is due to the protection conferred by specialized molecules on the parasite's cell surface. One such macromolecule is a novel glycoconjugate called lipophosphoglycan. This heterogeneous, lipid-containing polysaccharide is the major surface molecule of the parasite and has been implicated in a surprisingly large number of functions that may contribute to the parasite's pathogenesis. This review emphasizes the structural aspects of lipophosphoglycan and its possible functions and biosynthesis.

Fabrication and characterization of amorphous lithium electrolyte thin films and rechargeable thin-film batteries

Abstract: Amorphous oxide and oxynitride lithium electrolyte thin films were synthesized by r.f. magnetron sputtering of lithium silicates and lithium phosphates in Ar, Ar + O2, Ar + N2, or N2. The composition, structure, and electrical properties of the films were characterized using ion and electron beam, X-ray, optical, photoelectron, and a.c. impedance techniques. For the lithium phosphosilicate films, lithium ion conductivities as high as 1.4 × 10−6 S/cm at 25 °C were observed, but none of these films selected for extended testing were stable in contact with lithium. On the other hand, a new thin-film lithium phosphorus oxynitride electrolyte, synthesized by sputtering Li3PO4 in pure N2, was found to have a conductivity of 2 × 10-6 S/cm at 25 °C and excellent long-term stability in contact with lithium. Thin-films cells consisting of a 1 μm thick amorphous V2O5 cathode, a 1 μm thick oxynitride electrolyte film, and a 5 μm thick lithium anode were cycled between 3.7 and 1.5 V using discharge rates of up to 100 μA/cm2 and charge rates of up to 20 μA/cm2. The open-circuit voltage of 3.6 to 3.7 V of fully-charged cells remained virtually unchanged after months of storage.

Can altruism evolve in purely viscous populations

Abstract: Limited dispersal is often thought to facilitate the evolution of altruism by increasing the degree of relatedness among interacting individuals Limited dispersal can have additional effects, however, such as local population regulation, that inhibits the evolution of altruism Many models of structured populations assume that a viscous stage of the life cycle alternates with a global mixing stage, which allows the advantages of interactions among close relatives without the disadvantages of local population regulation Here we analyse a computer simulation model of ‘pure’ population viscosity, in which offspring are always deposited close to parents and no global mixing stage exists As expected, limited dispersal generates a high coefficient of relatedness among interacting individuals Patches of altruists, however, are unable to ‘export’ their productivity to other regions of the landscape and are easily invaded by selfish types from neighbouring patches Unlike models of alternating viscosity, in which high relatedness and local population regulation can be decoupled, these two opposing effects are inextricably linked in purely viscous populations, which therefore are not conducive to the evolution of altruistic traits

Why do female adders copulate so frequently

Abstract: MALES of most animal species will enhance their reproductive success if they mate often and with many different partners, whereas promiscuous mating is unlikely to increase a female's reproductive success. Why then is multiple copulation by females so common1–6? Many theoreticians have suggested that multiple copulations might enhance the viability of a female's offspring, either because of inadequate quantities of sperm from the first mating1,7, additional nutrients derived from the seminal fluid7,8 or some genetic advantage9–14. Our field studies on Swedish adders provide the first empirical evidence that multiple copulations, with different partners each time, increase offspring viability. This advantage apparently results from more intense sperm competition in the female's reproductive tract, resulting in a higher proportion of her ova being fertilized by genetically superior males.

Psychometric Evaluation of the Lexington Attachment to Pets Scale (Laps)

Abstract: This paper reports on the development and psychometric evaluation of a scale for assessing emotional attachment of individuals to their pets. Previous attachment scales have suffered variously from low internal consistency and reliance on small or nonrepresentative samples for their development. Telephone interviews of a random, representative sample of 412 pet owners in Fayette County, Kentucky, were completed in September 1990; a 69.5 percent response rate was achieved. From a preliminary set of 42 questions, a final 23-question instrument, the Lexington Attachment to Pets Scale (LAPS), was developed, having excellent psychometric properties. The scale is suitable for use with dog and cat owners. Data on internal consistency, factor structure, and item response theory (IRT) modeling are presented, along with correlations between the LAPS and several domains of variables known to relate to pet attachment.

Cytochrome b-245 is a flavocytochrome containing FAD and the NADPH-binding site of the microbicidal oxidase of phagocytes

Abstract: The NADPH oxidase of phagocytic cells is important for the efficient killing and digestion of ingested microbes. A very unusual low-potential cytochrome b (b-245) is the only redox molecule to have been identified in this system. The FAD-containing flavoprotein that binds NADPH and transfers electrons to the cytochrome has eluded identification for three decades. We show here that the haem/FAD ratio in the membranes does not change significantly on activation of this oxidase, indicating that the FAD is present in the membranes from the outset and not recruited from the cytosol. The FAD content of membranes from cells of patients with X-linked chronic granulomatous disease (CGD) lacking the cytochrome b was roughly one-quarter of that in normal subjects and in autosomal recessive CGD patients lacking the cytosolic protein p47-phox. Similar low amounts of FAD were present in uninduced promyelocytic (HL60) cells, suggesting that the low amount of FAD in cells from X-CGD patients was probably unrelated to this oxidase system. Cytochrome b-245 appears to bind both the haem and FAD, in a molar ratio of 2:1. The e.p.r. signal of the purified cytochrome was weak and had an asymmetric g(z) peak at g = 3.31. The purified cytochrome could be partially reflavinated (about 20%) in the presence of lipid. Amino acid sequence homology was detected between the beta-subunit of this cytochrome b and the ferredoxin-NADP+ reductase (FNR) family of reductases in the putative NADPH- and FAD-binding sites. 32P-labelled 2-azido-NADP was used as a photoaffinity label for the NADPH-binding site. Labelling that was competed off with NADP was observed in the region of the beta-subunit of the cytochrome. No labelling was seen in this region in X-CGD in three subjects in whom this cytochrome was missing and in a third in whom it was present but bore a Pro-His transposition in the putative NADPH-binding site. These studies indicate that cytochrome b-245 is a flavocytochrome, the first described in higher eukaryotic cells, bearing the complete electron-transporting apparatus of the NADPH oxidase.

Foundations of disjunctive logic programming

Abstract: Part 1 Introduction and background: motivation historical background. Part 2 Definitions and terminology: first-order theory - syntax first order theory - semantics logic programs - syntax logic programs - semantics - models and interpretations substitutions and unifiers fixpoint theory. Part 3 Declarative semantics: logical consequences model theory fixpoint theory comparison of definite and disjunctive logic programs. Part 4 Proof theory: query type and correct answers SLI resolution and SLD resolution soundness of SLI resolution completeness of SLI resolution computation rule comparison of SLD and SLI resolution. Part 5 Negation: generalized closed world assumption procedural interpretation for the GCWA non-herbrand models and the GCWA constructive answers. Part 6 Weak negation: weak generalized closed world assumption finite failure semantics fixpoint characterization completion theory procedural interpretation. Part 7 Normal logic programs: normal disjunctive logic programs the generalized disjunctive well-founded semantics stationary semantics comparison of semantics normal logic programs. Part 8 Proof theory - normal programs: SLIS resolution soundness of SLIS resolution completeness of SLIS resolution. Part 9 Disjunctive deductive databases: disjunctive deductive databases queries and answers incremental evaluation of hierarchical DDDB's model trees - a data structure for sets of minimal models incremental computation on model trees computing answers on trees meaningless models and denials. Part 10 Applications: view updates combining deductive databases.

Personality and psychopathology: an application of the five-factor model.

Abstract: Our review is concerned with the relationship of the five-factor model of personality to psychopathology, focusing in particular on Axis II personality disorders and depression. The five factors provide a particularly compelling model for interpreting the Axis II personality disorders as maladaptive variants of normal personality traits. However, we also discuss methodological and conceptual limitations of this application. There has been little research on the relationship of Openness, Agreeableness, and Conscientiousness to Axis I mental disorders, but considerable attention has been given to Neuroticism and Extraversion. We focus in particular on the difficulty in distinguishing between the various ways in which personality can relate to depression, either as a predisposition to, a complication of, a pathoplastic effect upon, or a spectrum variant of the mental disorder. We conclude with recommendations for future research.

Effects of dietary energy on control of luteinizing hormone secretion in cattle and sheep

Abstract: Prolonged restriction of dietary energy delays onset of puberty, disrupts cyclicity in sexually mature animals, and lengthens the postpartum anestrous period in domestic ruminants One important mechanism by which energy restriction impairs reproductive activity seems to be suppression of the increase in LH pulse frequency that is necessary for growth of ovarian follicles to the preovulatory stage Under-nutrition apparently inhibits pulsatile secretion of LH by reducing LHRH secretion by the hypothalamus The ability of an animal to sustain a high-frequency mode of pulsatile LH release is related to its metabolic status Mechanisms linking metabolic status to LHRH secretion have not been fully characterized Changes in body fat have been associated with changes in reproductive activity, but it is unlikely that body fat per se regulates LHRH secretion It is possible that pulsatile LHRH release is regulated by specific metabolites and(or) metabolic hormones that reflect nutritional status Alternatively, availability of oxidizable metabolic fuels, such as glucose and nonesterified fatty acids, may influence activity of neurons that control LHRH release Our understanding of how the central nervous system transduces information about nutritional status into neuroendocrine signals that control reproduction in cattle and sheep is limited by a lack of information concerning the nature of neurons controlling LHRH release in these species

Management considerations in heifer development and puberty.

Abstract: Management of replacement beef heifers should focus on factors that enhance physiological processes that promote puberty. Age at puberty is important as a production trait when heifers are bred to calve as 2-yr-olds and in systems that impose restricted breeding periods. Calving by 24 mo of age is necessary to obtain maximum lifetime productivity. Because the reproductive system is the last major organ system to mature, factors that influence puberty are critical. The influence of environment on the sequence of events leading to puberty in the heifer is dictated largely by the nutritional status of the animal and related effects on growth rate and development. Management strategies have been designed to ensure that heifers reach a prebreeding target weight that supports optimum reproductive performance, and consequences of inadequate or excessive development have been evaluated. Those strategies are based on evidence linking postweaning nutritional development with key reproductive events that include age at puberty and first breeding, conception, pregnancy loss, incidence and severity of dystocia, and postpartum interval to estrus. Management alternatives that ultimately affect lifetime productivity and reproductive performance of heifers begin at birth and include decisions that involve growth-promoting implants, creep-feeding, breed type and(or) species, birth date and weaning weight, social interaction, sire selection, and exogenous hormonal treatments to synchronize or induce estrus. Basic and applied future research efforts should converge to match in a realistic manner the production potential of the animal with available resources. Strategies that incorporate consideration of nutrition, genetics, and emerging management techniques will need to be tested to enable producers to make decisions that result in profit. This review evaluates the current status of knowledge relating to management of the replacement beef heifer and serves to stimulate research needed to enhance management techniques to ensure puberty at an optimal age.

Inhibition of human skin fibroblast collagenase, thermolysin, and Pseudomonas aeruginosa elastase by peptide hydroxamic acids.

Abstract: The hydroxamic acid HONHCOCH2CH(i-Bu)CO-L-Trp-NHMe, isomer 6A (GM 6001), inhibits human skin fibroblast collagenase with Ki of 0.4 nM using the synthetic thiol ester substrate Ac-Pro-Leu-Gly-SCH(i-Bu)CO-Leu-Gly-OEt at pH 6.5. The other isomer, 6B, which has the opposite configuration at the CH2CH(i-Bu)CO alpha-carbon atom, has a Ki of 200 nM for this enzyme. GM 6001 is one of the most potent inhibitors of human skin fibroblast collagenase yet reported. GM 6001 has a Ki of 20 nM against thermolysin and Pseudomonas aeruginosa elastase. Isomer 6B has a Ki of 7 nM against thermolysin and 2 nM against the elastase. 6A and 6B are the most potent hydroxamate inhibitors reported for these bacterial enzymes. The pattern of inhibition for all three enzymes suggests that isomer 6A is the (R,S) compound, stereochemically analogous to the L,L-dipeptide, and isomer 6B is the (S,S) compound, analogous to the DL-dipeptide. The tolerance of the D configuration by thermolysin and the elastase allows these inhibitors to discriminate between the human and bacterial enzymes simply by inversion of configuration at the CH2CH(i-Bu)CO alpha-carbon atom. Substitution of the potential metal liganding groups carboxylate and hydrazide for the hydroxamate group yields much weaker inhibitors for all three enzymes.

Effects of nutrition and season on the onset of puberty in the beef heifer

Abstract: Age at puberty is a major determinant of lifetime reproductive efficiency of beef cows. Research conducted during the past 20 yr has documented the major endocrine events leading to first ovulation in heifers. The critical event seems to be a prepubertal increase in pulsatile LH secretion. Environment influences timing of puberty onset in beef heifers. Nutrition and season are two of the better-defined variables that have been studied. Age at puberty is related inversely to plane of nutrition. The effect of nutrition on sexual maturation involves effects on timing of the prepubertal increase in LH secretion and seems to involve the LH pulse generating system located in the hypothalamus. The precise mechanism by which nutrition influences pulsatile LH secretion has not been elucidated, but signals reflecting metabolic status seem to be involved. Seasonal conditions of the early (birth to 6 mo of age) and late (6 to 12 mo of age) postnatal periods also influence timing of puberty onset in the heifer. Autumn-born heifers attain puberty at younger ages than do spring-born heifers, and exposure to spring-summer temperatures and photoperiods during the second 6 mo of life reduces age at puberty regardless of season of birth. Photoperiod may be the major seasonal cue that influences puberty onset in cattle. Limited evidence suggests that melatonin, a pineal hormone, is involved with transducing photic stimuli into neuroendocrine signals that influence LH secretion. If the physiological mechanisms mediating the effects of nutrition and season on timing of puberty onset are determined, then management strategies for reducing age at puberty can be enhanced.

IGF-I and IGF-II protect cultured hippocampal and septal neurons against calcium-mediated hypoglycemic damage.

Abstract: Insulin and insulin-like growth factors I and II (IGF-I and IGF-II) have recently been shown to have biological activity in central neurons, but their normal functions and mechanisms of action in the brain are unknown. Since central neurons are particularly vulnerable to hypoglycemia that results from ischemia or other insults, we tested the hypothesis that growth factors can protect central neurons against hypoglycemic damage in vitro. IGF-I and IGF-II (3-100 ng/ml) each prevented glucose deprivation-induced neuronal damage in a dose-dependent manner in rat hippocampal and septal cell cultures. High concentrations of insulin (greater than 1 microgram/ml) also protected neurons against hypoglycemic damage. Epidermal growth factor did not protect against hypoglycemic damage. Both IGFs and insulin were effective when administered 24 hr before or immediately following the onset of glucose deprivation. Direct measurements of intraneuronal calcium levels and manipulations of calcium influx demonstrated that calcium influx and sustained elevations in intraneuronal calcium levels mediated the hypoglycemic damage. IGF-I and IGF-II each prevented the hypoglycemia-induced elevations of intraneuronal free calcium. Studies with excitatory amino acid receptor antagonists and calcium channel blockers indicated that NMDA receptors did, and L-type calcium channels did not, play a major role in hypoglycemic damage. Taken together, these findings indicate that IGFs can stabilize neuronal calcium homeostasis and thereby protect against hypoglycemic damage.

Proposed definitions related to induced disease resistance

Abstract: A clear definition of induced disease resistance is lacking, even though the area has been extensively researched and described. The lack of a precise definition leads to potential confusion on whether an underlying mechanism for biological control is induced resistance. We propose definitions, which were developed at a NATO Advanced Research Workshop on biological control, for induced disease resistance and related terms. These definitions are intended to invoke debate and increase effective communication among investigators of induced resistance.

Gene family for an elicitor-induced sesquiterpene cyclase in tobacco

Abstract: The initial step in the conversion of the isoprenoid intermediate farnesyl diphosphate to the sesquiterpenoid phytoalexin capsidiol in elicitor-treated tobacco tissues is catalyzed by an inducible sesquiterpene cyclase [5-epi-aristolochene synthase (EAS)]. Two independent cDNA clones (cEAS1 and cEAS2) encoding EAS were isolated from an elicitor-induced tobacco cDNA library by differential hybridization and subsequently were characterized by hybrid selection--in vitro translation. Insertion of cEAS1, a partial cDNA clone encoding 175 C-terminal amino acids, into an Escherichia coli expression vector resulted in accumulation of a fusion protein immunodetectable with EAS-specific polyclonal antibodies. The cDNA clones were used to isolate two full-length EAS genes that mapped 5 kilobases (kb) apart on one 15-kb genomic clone. The nucleotide sequences of the structural gene components were identical from 388 base pairs (bp) upstream of the transcription initiation site to 40 bp downstream of the translation termination codon, suggesting a relatively recent duplication event. The genes consist of 1479-bp open reading frames, each containing five introns and specifying 56,828-Da proteins. The N-terminal amino acid sequence deduced from the genomic clones was identical to the first 16 amino acids of the EAS protein identifiable by Edman degradation. RNA blot hybridization with cEAS1 demonstrated a mRNA induction time course consistent with the induction of the EAS mRNA translational activity with maximum levels 4-6 h after elicitation. EAS mRNA was not detected in control cells. DNA blot-hybridization analysis of genomic DNA revealed a copy number of approximately 12-15 for EAS-like genes in the tetraploid tobacco genome. The conservation of a putative allelic prenyl diphosphate binding motif is also discussed.

School Participant Empowerment Scale: Assessment of Level of Empowerment within the School Environment

Abstract: Two hundred eleven teachers in public schools rated 68 beliefs about what makes them feel empowered in schools. The items were factor analyzed revealing six dimensions or subscales: (a) Decision Making, (b) Professional Growth, (c) Status, (d) Self-Efficacy, (e) Autonomy, and (f) Impact. A 38-item School Participant Empowerment Scale (SPES) was constructed by selecting marker items for each of the six dimensions. Obtained internal consistency estimates of reliability for the total scale was .94, and ranged from .81 to .89 for the six factor scales. Evidence of discriminant validity also was discussed.

Surface Roughness and Its Effects on the Heat Transfer Mechanism in Spray Cooling

Abstract: In the spray cooling of a heated surface, variations in the surface texture influence the flow field, altering the maximum liquid film thickness, the bubble diameter, vapor entrapment, bubble departure characteristics, and the ability to transfer heat. A new method for determining and designating the surface texture is proposed, and the effects of surface roughness on evaporation/nucleation in the spray cooling flow field studied. A one-dimensional Fourier analysis is applied to determine experimentally the surface profile of a surface polished with emery paper covering a spectrum of grit sizes between 0.3 to 22 {mu}m. Heat transfer measurements of liquid flow rates between 1 to 5 l/h and air flow rates between 0.1 to 0.4 l/s are presented. Maximum heat fluxes of 1,200 W/cm{sup 2} for the 0.3 {mu}m surface at very low superheats were obtained.