Showing papers by "University of Arizona published in 1986"

Strategic Brand Concept-Image Management:

Abstract: Conveying a brand image to a target market is a fundamental marketing activity. The authors present a normative framework, termed brand concept management (BCM), for selecting, implementing, and co...

A methodology for profiling consumers' decision-making styles

Abstract: Consumers use a variety of decision-making styles. This paper conceptualizes eight basic characteristics of these styles and develops a Consumer Styles Inventory to measure them empirically. Factor analysis of the Consumer Styles Inventory validates these eight consumer characteristics. A valid and reliable method for presenting a Profile of Consumer Style, based on measures of the eight style characteristics, is described. Unique findings of the research are discussed, and applications of the Consumer Styles Inventory in consumer education, consumer research, and family financial counseling are suggested.

Surface-polariton-like waves guided by thin, lossy metal films.

Abstract: The dispersion relations are solved for waves guided by a thin, lossy metal film surrounded by media of dielectric constant ${\ensuremath{\epsilon}}_{1}$ and ${\ensuremath{\epsilon}}_{3}$. For symmetric structures (${\ensuremath{\epsilon}}_{1}$=${\ensuremath{\epsilon}}_{3}$), there are the usual two Fano modes whose velocity and attenuation vary with film thickness. For very thin films, one of these modes can attain multicentimeter propagation distances when \ensuremath{\lambda}g1 \ensuremath{\mu}m. In addition, there are two leaky waves which correspond to waves localized at the ${\ensuremath{\epsilon}}_{1}$ (or ${\ensuremath{\epsilon}}_{3}$) dielectric-metal interface whose fields decay exponentially across the metal film and radiate an angular spectrum of plane waves into ${\ensuremath{\epsilon}}_{3}$ (or ${\ensuremath{\epsilon}}_{1}$, respectively). Both radiative waves can be interpreted as spatial transients, which could have physical significance near a transverse plane. When ${\ensuremath{\epsilon}}_{1}$\ensuremath{ e}${\ensuremath{\epsilon}}_{3}$, there are still four distinct solutions for a given film thickness, two radiative and two nonradiative. For lossy films, there are always two nonradiative solutions for thick enough films. As the thickness goes to infinity, the four solutions reduce to two waves, each radiative and nonradiative pair becoming degenerate. The physical interpretation of these solutions and their dependence on dielectric constant and wavelength are discussed.

An O ( ND ) difference algorithm and its variations

Abstract: The problems of finding a longest common subsequence of two sequencesA andB and a shortest edit script for transformingA intoB have long been known to be dual problems. In this paper, they are shown to be equivalent to finding a shortest/longest path in an edit graph. Using this perspective, a simpleO(ND) time and space algorithm is developed whereN is the sum of the lengths ofA andB andD is the size of the minimum edit script forA andB. The algorithm performs well when differences are small (sequences are similar) and is consequently fast in typical applications. The algorithm is shown to haveO(N+D 2) expected-time performance under a basic stochastic model. A refinement of the algorithm requires onlyO(N) space, and the use of suffix trees leads to anO(N logN+D 2) time variation.

Consumer Response to Television Commercials: The Impact of Involvement and Background Music on Brand Attitude Formation:

Abstract: Past research has examined the effect of level of involvement (high vs. low) on subjects’ reactions to persuasive communications. The authors suggest that high involvement can be differentiated int...

Seed plant phylogeny and the origin of angiosperms: An experimental cladistic approach

Abstract: We present a numerical cladistic (parsimony) analysis of seed plants plus progymnosperms, using characters from all parts of the plant body, outgroup comparison, and a method of character coding that avoids biases for or against alternative morphological theories. The robustness of the results was tested by construction of alternative trees and analysis of subsets of the data. These experiments show that although some clades are strongly supported, they can often be related to each other in very different but nearly equally parsimonious ways, apparently because of extensive homoplasy. Our results support Rothwell’s idea that coniferopsids are derived fromCallistophyton- like platyspermic seed ferns with saccate pollen, but the hypothesis that they evolved fromArchaeopteris- like progymnosperms and the seed arose twice is nearly as parsimonious. Meyen’s division of seed plants into radiospermic and primarily and secondarily platyspermic lines is highly unparsimonious, but his suggestion that ginkgos are related to peltasperms deserves attention. Angiosperms belong among the platyspermic groups, as the sister group of Bennettitales,Pentoxylon, and Gnetales, and this “anthophyte” clade is best related toCaytonia and glossopterids, although relationships with other combinations of Mesozoic seed fern taxa are nearly as parsimonious. These results imply that the angiosperm carpel can be interpreted as a modified pinnate sporophyll bearing anatropous cupules (=bitegmic ovules), while gnetalian strobili are best interpreted as aggregations of highly reduced bennettitalian flowers, as anticipated by Arber and Parkin and Crane. Our most parsimonious trees imply that the angiosperm line (though not necessarily all its modern features) extended back to the Triassic, but a later derivation of angiosperms from some species ofCaytonia or Bennettitales, which would be nearly as parsimonious, should also be considered. These results raise the possibility that many features considered key adaptations in the origin and rise of angiosperms (insectpollinated flowers, rapid reproduction, drought tolerance) were actually inherited from their gymnospermous precursors. The explosive diversification of angiosperms may instead have been a consequence of carpel closure, resulting in increased speciation rates due to potential for stigmatic isolating mechanisms and/or new means of dispersal. DNA sequencing of extant plants and better information on anatomy, chemistry, sporophyll morphology, and embryology of Bennettitales and Caytoniales and the morphological diversity of Mesozoic anthophytes could provide critical tests of relationships.

Bacterial solubilization of mineral phosphates: Historical perspective and future prospects

Abstract: Maximum crop yields require sufficient phosphorus fertilization. Only phosphate in a soluble ionic form (Pi) is effective as a mineral nutrient. Current fertilizer technology supplies the soil solution with Pi via the application of large amounts of phosphate salts. Problems with this technology include energy-intensive production processes, the need for large scale mechanical application with associated environmental consequences, and reprecipitation of the phosphate into insoluble mineral complexes. It has been estimated that in some soils up to 75% of applied phosphate fertilizer may be lost to the plant because of mineral phase reprecipitation. Many approaches, ranging from cultural practices to biological inoculants such as mycorrhizal fungi, are being employed to enhance P-use efficiency. One area that is currently under-investigated is the ability of certain types of bacteria to solubilize mineral and organic phosphates. A review of the literature in the area of bacterial phosphate solubilization confirms that this trait is displayed by a wide range of bacteria. The phosphate starvation inducible (PSI) organic phosphate-solubilizing capability of E. coli is a component of a coordinately regulated gene system: the pho regulon. It has long been known that bacteria are also capable of solubilizing mineral phosphates such as hydroxyapatite. To date there has been no systematic study of the genetics of this phenomenon. Data from my laboratory indicate that the bacterial mineral phosphate-solubilizing (MPS) trait is regulated by the external level of Pi This conclusion is supported by results obtained from several types of molecular genetic studies. It is proposed that bacteria have mineral phosphate solubilizing (mps) genes. The potential agronomic applications of bacterial mineral and organic P solubilizing systems are discussed.

The regulation of hemostasis: The protein C system

Abstract: We speak very frequently of the normal clotting time. In a glass tube?... Glass tubes have held the center of the stage for quite a long time but the process of clotting is now observed in plastic ...

Voyager 2 in the Uranian System: Imaging Science Results

Abstract: Voyager 2 images of the southern hemisphere of Uranus indicate that submicrometersize haze particles and particles of a methane condensation cloud produce faint patterns in the atmosphere. The alignment of the cloud bands is similar to that of bands on Jupiter and Saturn, but the zonal winds are nearly opposite. At mid-latitudes (-70 degrees to -27 degrees ), where winds were measured, the atmosphere rotates faster than the magnetic field; however, the rotation rate of the atmosphere decreases toward the equator, so that the two probably corotate at about -20 degrees . Voyager images confirm the extremely low albedo of the ring particles. High phase angle images reveal on the order of 10(2) new ringlike features of very low optical depth and relatively high dust abundance interspersed within the main rings, as well as a broad, diffuse, low optical depth ring just inside the main rings system. Nine of the newly discovered small satellites (40 to 165 kilometers in diameter) orbit between the rings and Miranda; the tenth is within the ring system. Two of these small objects may gravitationally confine the e ring. Oberon and Umbriel have heavily cratered surfaces resembling the ancient cratered highlands of Earth's moon, although Umbriel is almost completely covered with uniform dark material, which perhaps indicates some ongoing process. Titania and Ariel show crater populations different from those on Oberon and Umbriel; these were probably generated by collisions with debris confined to their orbits. Titania and Ariel also show many extensional fault systems; Ariel shows strong evidence for the presence of extrusive material. About halfof Miranda's surface is relatively bland, old, cratered terrain. The remainder comprises three large regions of younger terrain, each rectangular to ovoid in plan, that display complex sets of parallel and intersecting scarps and ridges as well as numerous outcrops of bright and dark materials, perhaps suggesting some exotic composition.

Gender, lifestyles, and victimization: beyond routine activity.

Abstract: Using data from a national survey of high school seniors and a study of high school students in Tucson, Arizona, this paper tests hypotheses about gender, routine activities, and delinquent activities as correlates of teenage victimization. The results are consistent with the hypotheses and suggest the following generalizations: (1) activities which involve the mutual pursuit of fun are more victimogenic than activities which passively put people at risk; (2) delinquent activity is positively related to victimization; (3) delinquent activity is more strongly related to victimization than nondelinquent activities; and (4) gender differences in victimization are reduced considerably by controls for delinquent activity. While offense activity cannot be demonstrated to precede victimization using cross-sectional data, the results do demonstrate the potential importance of delinquent activity in explanations of victimization among youths.

Grain processing effects on starch utilization by ruminants.

Abstract: Starch utilization may be markedly enhanced by proper grain processing; however, extent of improvement is primarily dependent upon the ruminant species, grain source and method of processing. Grain processing has less impact on starch digestion by sheep than cattle. The magnitude of improvement is inverse to the starch digestion values for nonprocessed (or minimally processed) grains. Utilization of sorghum grain starch is improved most by extensive processing, and then corn, with little improvement in barley starch digestion. Studies comparing processing effects on barley or wheat starch utilization by cattle were not found. Steam-flaking consistently improves digestibility of starch by cattle fed corn- or sorghum grain-based diets over whole, ground or dry-rolled processes. Other extensive processing methods appear to enhance starch digestibility of corn and sorghum grain to a similar extent as steam-flaking, but comparative data are too limited to quantitate adequately effects of these methods. This improvement in starch utilization appears to be the primary reason for enhanced feed conversion of cattle fed diets high in these processed grains. The major site of cereal grain starch digestion is usually the rumen. Processing increases microbial degradation of starch in the rumen and decreases amounts of starch digested post-ruminally. Rates of in vitro amylolytic attack of starch in cereal grains by both ruminal microbial and pancreatic enzyme sources are improved by processing methods employing proper combinations of moisture, heat and pressure. In vitro and in situ studies suggest that much of the increase in ruminal starch fermentation with steam-flaking is due to changes in starch granular structure, which produces additive effects beyond those of decreasing particle size. Thus, efficiency of ruminal starch fermentation by cattle appears to be improved by proper processing of corn and sorghum grain. Processing and grain source studies both suggest that maximal total tract starch digestibility is positively related to the extent of digestion in the rumen.

Theory of a microscopic maser

Abstract: We present the theory of a truly microscopic maser consisting of a single-mode high-Q resonator in which a monoenergetic beam of excited two-level atoms is injected at such a low flux that at most one atom at a time is present inside the cavity. Both a microscopic theory and a heuristic Fokker-Planck approach are presented. We show that the micromaser exhibits a number of novel features that are averaged out in usual masers and lasers. First, the field is in general sub-Poissonian, which reflects the quantization of both the field and its sources. Second, the onset of maser oscillations may be followed by a succession of abrupt transitions in the state of the field. Finally, as the atomic flux through the resonator is increased, the maser threshold acquires characteristics of a continuous phase transition, whereas the subsequent changes in the field distribution become analogous to first-order phase transitions.

On the large-scale structures in two-dimensional, small-deficit, turbulent wakes

Abstract: A systematic study of two-dimensional, turbulent, small-deficit wakes was carried out to determine their structure and the universality of their self-preserving states. Various wake generators, including circular cylinders, a symmetrical airfoil, a flat plate, and an assortment of screens of varying solidity, were studied for a wide range of downstream distances. Most of the generators were tailored so that their drag coefficients, and therefore their momentum thicknesses, were identical, permitting comparison at identical Reynolds numbers and aspect ratios. The flat plate and airfoil had a small, trailing-edge flap which could be externally driven to introduce forced sinuous oscillations into the wake. The results indicate that the normalized characteristic velocity and length scales depend on the initial conditions, while the shape of the normalized mean velocity profile is independent of these conditions or the nature of the generator. The normalized distributions of the longitudinal turbulence intensity, however, are dependent on the initial conditions.Linear inviscid stability theory, in which the divergence of the mean flow is taken into account, predicts quite well the amplification and the transverse distributions of amplitudes and phases of externally imposed sinuous waves on a fully developed turbulent wake generated by a flat plate. There is a strong indication that the large structures observed in the unforced wake are related to the two-dimensional instability modes and therefore can be modelled by linear stability theory. Furthermore, the interaction of the two possible modes of instability may be responsible for the vortex street-type pattern observed visually in the small-deficit, turbulent wake.

Quantum Theory of Measurement

Abstract: Quantum mechanics was discovered sixty-one years ago in 1925. It began with Heisenberg’s introduction of matrix mechanics, which was followed by Schrodinger finding his wave equation. Then Dirac gave a formulation of quantum mechanics that contained the two earlier theories as special cases and was much more general. The interpretation of the wave function as a probability amplitude was added by Born in 1926. The following discussion of the problem of measurement in quantum mechanics is limited to the nonrelativistic theory. Hence, there will be no mention of photons or spin. No doubt I will be taking other things for granted and I hope you will be able to infer them from the context. The Born probability interpretation was very well suited for discussing the blackening of a photographic plate exposed to a beam of electrons scattered by an atomic system. It was necessary to decide whether the wave function represented a beam of many electrons or only a single electron. One knows now that for the analysis of most such experiments, the theory is applied in a probabilistic way for a single electron, and the blackening of the plate by a beam of many electrons is worked out by plausible nonquantum mechanical considerations. The absolute square of the wave function at a point of the plate gives the probability for finding the electron there. If we had only to deal with that kind of problem in wave mechanics, there might not have been need for this conference. However, quantum mechanics lent itself very naturally to an enormous generalization of the theory of measurement. Dirac had introduced the two ideas of states and observables. The state was a generalization of the wave function, but without the emphasis on space coordinates associated with the SchrBdinger wave function. Observables were physical quantities that could be represented by Hermitian operators that were often, but not always, taken over from classical mechanics. Rules were given for calculation of real numbers (called expectation values) for any observable of a system in any of its states. The operator observables had eigenstates and eigenvalues. For the Hamiltonian observable, H(q,p), of a conservative dynamical system, the eigenstates were in close correspondence with the stationary states of the corresponding wave mechanical problem, and the eigenvalues were the stationary state energies known from the earlier quantum theory of Bohr. The structure of quantum mechanics makes it very natural to pretend that some (if not all) of the observables that characterize a dynamical system can be “measured” experimentally at least in principle. The following assumptions are made: If the state, 9, is one of the eigenstates, 9,, of the observable, R, a measurement of R should give the corresponding eigenvalue, R,. A measurement of observable Cl for a system in any state, 9, should give one of the eigenvalues, On, of 0. If this state, 9, is a linear combination of eigenstates of the form,

Reduction of Poisson manifolds

Abstract: Reduction in the category of Poisson manifolds is defined and some basic properties are derived. The context is chosen to include the usual theorems on reduction of symplectic manifolds, as well as results such as the Dirac bracket and the reduction to the Lie-Poisson bracket.

Body size, ecological dominance and Cope's rule

Abstract: We present data and analyses demonstrating that large species utilize a disproportionately large share of the resources within local ecosystems. Even though small species tend to have higher local population densities, these are not sufficient to compensate for their lower rates of energy use per individual. The relationship is very general; holding for example for birds, mammals, fish and plants. We suggest that several ecological advantages enable larger species and larger individuals within species to monopolize resources, and that the resulting selection pressures are responsible for the evolutionary trend towards increasing body size seen in many phyletic lineages. Our results contradict important studies1–4 that have concluded that species of small body size use at least as large a proportion of the resources within ecosystems as their larger relatives.

The true value of lambda would appear to be zero: an essay on career criminals, criminal careers, selective incapacitation, cohort studies, and related topics*

Abstract: The idea of selective incapacitation and the distinction between prevalence and incidence (participation and lambda) justify the search for a group of offenders whose criminality does not decline with age and who may be identified solely on the basis of legally relevant variables. This paper questions such research, arguing that the decline in age with crime characterizes even the most active offenders. and that the distinction between incidence and prevalence does not deserve the theoretical, research, or policy attention it has been claimed to merit (Farrington, 1985; Blumstein and Graddy, 1981–1982). In doing so, it relies on research results widely accepted in criminology. Thus, the current focus of criminological research on the “career criminal,” on selective incapacitation, and on longitudinal research remains unjustified.

Feedback to first language learners: the role of repetitions and clarification questions.

Abstract: The conclusion that information regarding the grammatically of children's speech is unavailable in parental input has recently been challenged (Moerk 1983 a, b, Hirsh-Pasek, Treiman & Schneiderman 1984). The present study expanded on this research by broadening the definition of ‘negative feedback’ and by describing individual styles of mother–child dialogues. The purpose was to investigate whether mothers of four 2-year-old children responded differentially to their children's well-formed or ill-formed utterances with explicit and implicit feedback. The middle-class, English-speaking, mother–child dyads were recorded in a naturalistic context at home during play and eating activities. Explicit and implicit feedback were different in terms of the proportion of responses available to the child and their relation to well-formed and ill-formed utterances. The style of response was similar for most analyses across the four mothers.

Predator-induced shell dimorphism in the acorn barnacle chthamalus anisopoma.

Abstract: Field experiments were conducted in order to determine the nature of shell dimorphism in the acorn barnacle Chthamalus anisopoma and the adaptive significance of the atypical form. The typical morph has the conical shape which is characteristic of acorn barnacles, while the atypical morph appears bent over, with the rim of its aperture oriented perpendicular to its base. The experiments showed that: 1) the bent-over morphology is an environmentally-induced de- velopmental response to the presence of a carnivorous gastropod (Acanthina angelica) and 2) that "bents" are more resistant than "conics" to specialized predation by this snail. The results also showed that predation by A. angelica is patchy and heaviest in the near vicinity of cracks and crevices, which it uses as refuges during periods of tidal inundation. Because predation is patchy and bents are less fecund and grow slower than conics, the conditional developmental strategy is likely to be favored over strict genetical control of shell morphology.

Geochemical constraints on core formation in the Earth

Abstract: New experimental data on the partitioning of siderophile and chalcophile elements among metallic and silicate phases may be used to constrain hypotheses of core formation in the Earth. Three current hypotheses can explain gross features of mantle geochemistry, but none predicts siderophile and chalcophile element abundances to within a factor of two of observed values. Either our understanding of metal-silicate interactions and/or our understanding of the early Earth requires revision.

High-Resolution Climatic Analysis and Southwest Biogeography

Abstract: Meteorologists and climatologists have produced significant new data on the fluid dynamics of the atmosphere, thus allowing biologists to examine more closely the cause-effect relation between the large-scale structure of the atmosphere and the dominant patterns of global biogeography The inability to characterize the high-frequency variability of the weather has constrained such efforts A method that allows year-to-year patterns of weather variability to be characterized in the contexts of global warming and cooling trends is applied in a combined analysis of long-term monthly weather records and data from an ecological monitoring project in southern New Mexico The analysis suggests a cause-effect hypothesis of recent desertification in the North American Southwest The links between the atmosphere and the biosphere are based on the fundamentally different responses to specific weather regimes of semidesert grasses with a C(4) photosynthetic pathway and desert shrubs with a C(3) photosynthetic pathway The hypothesis appears to be of sufficient generality to explain the complex, but well-documented, floristic changes that have occurred in the same region since the last glacial maximum

Optimized movement trajectories and joint stiffness in unperturbed, inertially loaded movements

Abstract: An attempt is made to integrate theoretically the mechanical, electromyographic, and psychophysical lines of inquiry into the control of movement by investigating the significance of joint stiffness in the reduction of effort. Attention is focused on single-joint, unperturbed movements of specified duration performed from one specified position to another in the presence of an inertial load. A theoretical measure of the sense of effort is formulated in the light of psychophysical observations and mechanical considerations. This measure is such that it is increased by reciprocal changes in the central drives to opposing sets of muscles, as well as by enhancement of joint stiffness. Mathematical analysis of the interplay of these factors reveals that, in any given condition, the minimization of this measure of effort necessitates a particular value of joint stiffness and a particular trajectory of movement. The predicted stiffness and trajectory are shown to be in quantitative agreement with available observations. In addition, the conditions in which a higher value of stiffness is predicted to be advantageous for reducing the effort are shown to be the conditions that are known to promote greater coactivation of the agonist and antagonist muscles. It is concluded that the seemingly wasteful coactivation may serve to optimize the stiffness. The stiffness, therefore, need not be viewed simply as a means of resisting imposed perturbations, but as a means of reducing the alterations in the central drives necessary for the performance of movement, thereby reducing the effort.

Characterization of a new drug-resistant human myeloma cell line that expresses P-glycoprotein.

Abstract: Multiple myeloma is a disease with a high initial chemotherapeutic response but virtually no cures due to emergence of drug resistance. A doxorubicin-resistant human myeloma cell line (8226/Dox) has been selected from the myeloma cell line RPMI8226 by continuously exposing cells to gradually increasing doses of doxorubicin. The resistant phenotype has been retained for over 2 months despite growth in drug-free medium. The resistant subline was cross-resistant to mitoxantrone, acronycine, etoposide, and vincristine. The 8226/Dox cell line remained sensitive to melphalan but acquired collateral sensitivity to dexamethasone. Intracellular doxorubicin accumulation, as measured by [14C]doxorubicin and high-performance liquid chromatography, was decreased by 54% at 1 h for 8226/Dox compared to the sensitive line. Efflux of doxorubicin was significantly greater in the resistant subline as compared to the sensitive parent cell line. Membrane analysis using immunoblotting techniques detected increased expression of the integral membrane protein P-glycoprotein (Mr 170,000) in the resistant subline. Cytogenetic analysis of 8226/Dox revealed a 7q-anomaly not seen in the parent cell line. No double minutes or homogeneously staining regions were observed. The drug sensitivity/resistance pattern of the resistant cell line correlates well with clinical observations indicating the potential of this cell line as a model for resistance in multiple myeloma.

Discrete-time growth-dispersal models

Abstract: Integrodifference equations are discrete-time models that share many of the attributes of scalar reaction-diffusion equations. At the same time, they readily exhibit period doubling and chaos. We examine the properties of some simple integrodifference equations.

A hierarchical approach for constitutive modelling of geologic materials

Abstract: SUMMARY A hierarchical concept is proposed for the development of constitutive models to account for various factors that influence behaviour of (geologic) materials. It permits evolution of models of progressively higher grades from the basic model representing isotropic hardening with associative behaviour. Factors such as non-associativeness and induced anisotropy due to friction and cyclic loading, and softening are introduced as corrections or perturbations to the basic model. The influence of these factors is captured through non-associativeness manifested by deviation from normality of the plastic strain increments to the yield surface, F. Details of four models: isotropic hardening with associative behaviour, isotropic hardening with non-associative behaviour, general anisotropic hardening and strain-softening with a damage variable are presented. They are verified with respect to laboratory multiaxial test data under various paths of loading, unloading and reloading for typical soils, rock and concrete. The proposed concept is general, yet sufficiently simplified in terms of physical understanding, number of constants and their physical meanings, determination of the constants and implementation.

Pathogenesis of diabetic neuropathy.

Abstract: Samples of lumbosacral trunk, posterior tibial nerve, and sural nerve obtained at autopsy from diabetic and nondiabetic patients without mononeuropathy multiplex were evaluated using 1-μ-thick epoxy sections and teased nerve fiber preparations. Focal fascicular lesions characterized by reduced density of myelinated axons within fascicles were found predominantly in the specimens from diabetics, mainly in the posterior tibial nerve and lumbosacral trunk. In severe examples, the perineurium and even surrounding epineurium were damaged, stamping the lesions as ischemic. In addition, identical lesions were found in biopsies of nerves of nondiabetics with vascultis. Density of myelinated fibers at the three sites demonstrated a proximal–distal graded loss that was significantly greater in the diabetic samples. The loss from the lumbosacral trunk to the posterior tibial nerve was correlated with the density of focal lesions in the lumbosacral trunk in the diabetic (p = 0.025), indicating that distal fiber loss was partly due to the focal lesions. Teased nerve fiber abnormalities were common only in sural nerves of diabetics, suggesting that they are secondary. We conclude that beyond the possible metabolic abnormalities involved in the genesis of diabetic polyneuropathy, focal fascicular lesions, likely due to diabetic microangiopathy, are also important in the development of diabetic neuropathy.

Cytokinin activity induced by thidiazuron.

Abstract: The diphenylurea derivative thidiazuron induces a variety of cytokinin responses. Levels above 5 × 10−9 molar and 4 × 10−7 molar stimulate maximum soybean callus growth and radish cotyledon expansion, respectively. A wider range of dose response related effects follows thidiazuron induced tobacco plant regeneration. Analysis of soybean callus extracts strongly suggests that thidiazuron treatment creates an accumulation and/or synthesis of purine cytokinins, able to induce the growth, expansion and regeneration, mentioned above.