Showing papers by "University of Kansas published in 1973"

Textural Features for Image Classification

Abstract: Texture is one of the important characteristics used in identifying objects or regions of interest in an image, whether the image be a photomicrograph, an aerial photograph, or a satellite image. This paper describes some easily computable textural features based on gray-tone spatial dependancies, and illustrates their application in category-identification tasks of three different kinds of image data: photomicrographs of five kinds of sandstones, 1:20 000 panchromatic aerial photographs of eight land-use categories, and Earth Resources Technology Satellite (ERTS) multispecial imagery containing seven land-use categories. We use two kinds of decision rules: one for which the decision regions are convex polyhedra (a piecewise linear decision rule), and one for which the decision regions are rectangular parallelpipeds (a min-max decision rule). In each experiment the data set was divided into two parts, a training set and a test set. Test set identification accuracy is 89 percent for the photomicrographs, 82 percent for the aerial photographic imagery, and 83 percent for the satellite imagery. These results indicate that the easily computable textural features probably have a general applicability for a wide variety of image-classification applications.

They spoke in defense of themselves: On the generic criticism of apologia

Abstract: The family of apologetic speeches, composed of responses to charges made against a person's character, has yet to receive critical attention as a genre. This essay, based upon the study of apologia from different historical periods, identifies four types of rhetorical strategies commonly found in such addresses. Rhetors typically employ these strategies in combinations that produce four discernible subgenres of the apologetic form: (a) absolutive, (b) vindicative, (c) explanative, and (d) justificative. This mapping of the genre should serve as an aid in the generic criticism of apologia.

Population Cycles in Small Rodents

Abstract: We conclude that population fluctuations in Microtus in southern Indiana are produced by a syndrome of changes in birth and death rates similar to that found in other species of voles and lemmings. The mechanisms which cause the changes in birth and death rates are demolished by fencing the population so that no dispersal can occur. Dispersal thus seems critical for population regulation in Microtus. Because most dispersal occurs during the increase phase of the population cycle and there is little dispersal during the decline phase, dispersal is not directly related to population density. Hence the quality of dispersing animals must be important, and we have found one case of increased dispersal tendency by one genotype. The failure of population regulation of Microtus in enclosed areas requires an explanation by any hypothesis attempting to explain population cycles in small rodents. It might be suggested that the fence changed the predation pressure on the enclosed populations. However, the fence was only 2 feet (0.6 meter) high and did not stop the entrance of foxes, weasels, shrews, or avian predators. A striking feature was that the habitat in the enclosures quickly recovered from complete devastation by the start of the spring growing season. Obviously the habitat and food quality were sufficient to support Microtus populations of abnormally high densities, and recovery of the habitat was sufficiently quick that the introduction of new animals to these enclosed areas resulted in another population explosion. Finally, hypotheses of population regulation by social stress must account for the finding that Microtus can exist at densities several times greater than normal without "stress" taking an obvious toll. We hypothesize that the prevention of dispersal changes the quality of the populations in the enclosures in comparison to those outside the fence. Voles forced to remain in an overcrowded fenced population do not suffer high mortality rates and continue to reproduce at abnormally high densities until starvation overtakes them. The initial behavioral interactions associated with crowding do not seem sufficient to cause voles to die in situ. What happens to animals during the population decline? Our studies have not answered this question. The animals did not appear to disperse, but it is possible that the method we used to measure dispersal (movement into a vacant habitat) missed a large segment of dispersing voles which did not remain in the vacant area but kept on moving. Perhaps the dispersal during the increase phase of the population cycle is a colonization type of dispersal, and the animals taking part in it are likely to stay in a new habitat, while during the population decline dispersal is a pathological response to high density, and the animals are not attracted to settling even in a vacant habitat. The alternative to this suggestion is that animals are dying in situ during the decline because of physiological or genetically determined behavioral stress. Thus the fencing of a population prevents the change in rates of survival and reproduction, from high rates in the increase phase to low rates in the decline phase, and the fenced populations resemble "mouse plagues." A possible explanation is that the differential dispersal of animals during the phase of increase causes the quality of the voles remaining at peak densities in wild populations to be different from the quality of voles at much higher densities in enclosures. Increased sensitivity to density in Microtus could cause the decline of wild populations at densities lower than those reached by fenced populations in which selection through dispersal has been prevented. Fencing might also alter the social interactions among Microtus in other ways that are not understood. The analysis of colonizing species by MacArthur and Wilson (27) can be applied to our studies of dispersal in populations of Microtus. Groups of organisms with good dispersal and colonizing ability are called r strategists because they have high reproductive potential and are able to exploit a new environment rapidly. Dispersing voles seem to be r strategists. Young females in breeding condition were over-represented in dispersing female Microtus (17). The Tf(C)/Tf(E) females, which were more common among dispersers during the phase of population increase (Fig. 6), also have a slight reproductive advantage over the other Tf genotypes (19). Thus in Microtus populations the animals with the highest reproductive potential, the r strategists, are dispersing. The segment of the population which remains behind after the selection-via-dispersal are those individuals which are less influenced by increasing population densities. These are the individuals which maximize use of the habitat, the K strategists in MacArthur and Wilson's terminology, or voles selected for spacing behavior. Thus we can describe population cycles in Microtus in the same theoretical framework as colonizing species on islands. Our work on Microtus is consistent with the hypothesis of genetic and behavioral effects proposed by Chitty (6) (Fig. 7) in that it shows both behavioral differences in males during the phases of population fluctuation and periods of strong genetic selection. The greatest gaps in our knowledge are in the area of genetic-behavioral interactions which are most difficult to measure. We have no information on the heritability of aggressive behavior in voles. The pathways by which behavioral events are translated into physiological changes which affect reproduction and growth have been carefully analyzed by Christian and his associates (28) for rodents in laboratory situations, but the application of these findings to the complex field events described above remains to be done. Several experiments are suggested by our work. First, other populations of other rodent species should increase to abnormal densities if enclosed in a large fenced area (29). We need to find situations in which this prediction is not fulfilled. Island populations may be an important source of material for such an experiment (30). Second, if one-way exit doors were provided from a fenced area, normal population regulation through dispersal should occur. This experiment would provide another method by which dispersers could be identified. Third, if dispersal were prevented after a population reached peak densities, a normal decline phase should occur. This prediction is based on the assumption that dispersal during the increase phase is sufficient to ensure the decline phase 1 or 2 years later. All these experiments are concerned with the dispersal factor, and our work on Microtus can be summarized by the admonition: study dispersal.

An Electrochemical Detector for Liquid Chromatography with Picogram Sensitivity

Abstract: A simple liquid chromatograph with an extremely sensitive electrochemical detector is described. The detector, which can be constructed for lees than $5.00 (excluding electronics), has an actual dead volume of < 1 μl and operates well in the 50–100 picogram region. Routine quantitative work at the 5–10 nanogram level is described. Potential applications to the analysis of biogenic amines are discussed.

Early Syntactic Development: A Cross-Linguistic Study with Special Reference to Finnish

Abstract: 1. Introduction 2. Data collection 3. The pivot grammar approach 4. Early stage 1 speech 5. Late stage 1 speech 6. problems with the transformational grammar approach 7. The case grammar approach 8. Summary and conclusions Appendices.

Resource Utilization: Temporal and Spatial Components of Bat Activity in Central Iowa

Abstract: Foraging activity of insectivorous bats was studied from April through October in central Iowa. Temporal activity was quantified by recording capture times throughout feeding periods, and spatial patterns were examined by measuring the abundance and diversity of species in three contrasting habitats. Six species, Myotis lucifugus, Myotis keenii, Lasionycteris noctimgans, Eptesicus fuscus, Lasiurus borealis , and Lasiurus cinereus , were characterized by initial periods of foraging occurring within 5 hours after sunset. Myotis keenii and L. noctivagans had distinct secondary periods of activity, but other species showed only minor secondary periods, or complete cessation of activity, following the initial foraging period. The modes of initial and secondary activity of L. noctivagans, L. borealis and L. cinereus showed almost complete displacement and corresponded to peak periods of nocturnal insect activity, suggesting a mechanism by which some insectivorous bats may partition environmental resources. Those species showing overlap in temporal foraging ( M. keenii and L. noctivagans on the one hand, and M. lucifugus, E. fuscus , and L. borealis on the other) may have evolved spatial strategies to reduce competition for resources. Intraspecific foraging patterns of three species examined may reflect resource partitioning or, alternatively, secondary foraging activity owing to different energy demands of young and lactating females.

Social control of form diversity and the emergence of new forms in children's blockbuilding.

Abstract: The blockbuilding behavior of three preschool girls was analyzed in terms of the forms manifest in any completed block construction, and found to contain few different forms in baseline sessions. Social reinforcement, given contingent on the production of any form not previously constructed within the current session (i.e., every first appearance of any form within a session was reinforced but no subsequent appearances of that form within that session were), increased the number of different forms built per sessions. Social reinforcement, given for all second and later appearances within the session, decreased the number of different forms built per session. Furthermore, it was found that new forms (forms never seen before in the child's total prior sequence of blockbuilding sessions) emerged at higher rates during periods of reinforcement of different forms (first appearances) than during periods of baseline or reinforcement of same forms (second and later appearances).

The effects of play materials on social play

Abstract: To increase cooperative and social behaviors in children, contingency management programs have been successfully employed. This study examined the possibility that children's social behavior might also be significantly influenced by the nature of the available play materials. Children in an urban recreation center were systematically provided with toys designed for social or isolate play. It was found that social play occurred only 16% of the time when the children were provided with “isolate” toys, whereas social play occurred 78% of the time when children were provided with “social” toys. Thus, the selection of play materials should be an important consideration in any effort to teach children social behaviors.

The effects of experimenter's instructions, feedback, and praise on teacher praise and student attending behavior.

Abstract: Systematic use of experimenter's instructions, feedback, and feedback plus social praise was used to increase teacher praise for student attending behavior of three elementary school teachers. Experimenter's verbal interactions with teachers, teacher's verbal praise for student behaviors, and pupil attending behavior were recorded during baseline conditions. As the three successive experimental conditions were introduced first with Teacher A, then with Teacher B, in a multiple baseline design, behaviors of the experimenter, the two teachers, and eight students were measured and recorded. In the cases of Teachers A and B, experimental condition one (Instructions) and experimental condition two (Feedback) produced inconclusive results. Experimental condition three (Feedback Plus Social Praise) produced more teacher praise for student attending behavior. The entire “Package” of Experimenter's Instructions, Feedback, and Feedback Plus Social Praise was introduced to Teacher C in a single experimental condition. As in the cases of Teachers A and B, behaviors measured were: (1) the experimenter's verbal interactions, (2) the teacher's praise of students, and (3) the student's attending behavior. Introduction of the “Package” also produced more teacher praise for student attending behavior.

Use and analysis of the "Good Behavior Game" to reduce disruptive classroom behavior.

Abstract: A recent study reported procedures (the "good behavior game") for reducing disruptive classroom behavior. Replication of the procedures of the "good behavior game" in two classrooms showed it to be an effective technique for reducing disruptive talking and out-of-seat behavior. Further experimental analysis indicated that the effective components of the game were division of the class into teams, consequences for a team winning the game, and criteria set for winning the game. Although disruptive behavior was markedly reduced by the game, the reductions were correlated with only slightly improved accuracy of academic performance in the one classroom where academic performance was measured.

Pharmacokinetics of methotrexate.

Abstract: The pharmacokinetics of SH‐methotrexate were studied in 22 patients with malignancies. Following the intravenous administration of 30 mg methotrexate (Mtx) per square meter, the plasma disappearance was triphasic with half‐lifes of 0.7.5 ± 0.11,3.49 ± 0 . .55, and 26.99 ± 4.44 hours, respectively. The urinary excretion of radioactivity paralleled the plasma data for most patients. A metabolite was found in urine that eluted before Mix when chromatographed on a diethylaminoethyl (DEAE) cellulose column. The excretion of this metabolite reached steady state and accounted for 20 (14 to 37) per cent of the radioactivity in urine after 30 hours. Our observation that Mtx has a long terminal half‐life may explain the high incidence of tOXicity in patients receiving chronic low‐dose Mtx therapy.

Effect of Interchain Coupling on Electron-Spin Resonance in Nearly One-Dimensional Systems

Abstract: We present a theoretical and experimental study of the electron-spin-resonance (ESR) line shape in Heisenberg linear-chain systems which have small but non-negligible interchain coupling. Weak interchain coupling can drastically alter the characteristic one-dimensional line shape as well as produce three-dimensional ordering below a critical temperature ${T}_{N}$. Since ${T}_{N}$ is observable in a majority of "linear-chain" compounds, the treatment given here has broad application to ESR and structure studies. The rate for off-chain diffusion is proportional to ${J}^{\ensuremath{'}}{(\frac{{J}^{\ensuremath{'}}}{J})}^{\frac{1}{3}}$, where $J$ and ${J}^{\ensuremath{'}}$ are the intra- and interchain couplings, respectively. This dependence comes from the slow rate of diffusion in one dimension. Interchain spin flips then proceed at a rate considerably faster than would be expected on the basis of an anisotropic diffusion equation or transition probabilities. As a consequence, interchain coupling can be very effective in limiting the one-dimensional divergences which produce a non-Lorentzian line. Measurements are reported in Cu${(\mathrm{N}{\mathrm{H}}_{3})}_{4}$S${\mathrm{O}}_{4}$\ifmmode\cdot\else\textperiodcentered\fi{}${\mathrm{H}}_{2}$O (CTS), CsMn${\mathrm{Cl}}_{3}$\ifmmode\cdot\else\textperiodcentered\fi{}2${\mathrm{H}}_{2}$O (CMC), and Cu${\mathrm{Cl}}_{2}$\ifmmode\cdot\else\textperiodcentered\fi{}2N${\mathrm{C}}_{5}$${\mathrm{H}}_{5}$ (CuPC). CTS has a Lorentzian line shape out to almost 14 half-widths, which is consistent with our theory and the observed ${T}_{N}$. The line shape in CMC is only moderately non-Lorentzian. The value of ${J}^{\ensuremath{'}}$ required to fit the present theory to the line-shape data is between 2 and 4 times greater than estimated from the observed ${T}_{N}$ and spinwave spectrum in CMC. The line shape in CuPC is highly non-Lorentzian, from which we estimate $\frac{{J}^{\ensuremath{'}}}{J}\ensuremath{\approx}2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$. This is in reasonable accord with a recent measurement of ${T}_{N}$ in the compound.

Peripheral levels of estrogen in the cyclic hamster.

Abstract: Peripheral levels of plasma estrone (E1) and estradiol (E2), as measured by RIA, showed little correspondence in the cycling hamster. A diurnal pattern of Ex was apparent during the cycle with peak levels reached at 2200. Estradiol levels were low on the first 2 days of the cycle, correlated with the absence of antral follicles, but were higher at 2200 of day 2. A peak was reached at 1400 of day 3 (approximately 90 pg/ml) and the levels remained elevated for at least 8 hr. E2 was depressed at 0900 of day 4, but this was followed by an almost linear increase between 0900 and 1500 when the highest value for the estrous cycle was attained (186.6 pg/ml). A sharp decrease, down to baseline values, followed. The day 4 peak in E2 was temporally related to the preovulatory surge in LH and an abrupt increase in ovarian progesterone. Phenobarbital (Phen) injected to day 4 cycling animals prevented the E2 peak at 1500, whereas the addition of 5 μg of LH restored E2 to normal values. However, E1 was not affected by e...

Independent control of a pre-school child's aggression and peer interaction by contingent teacher attention.

Abstract: This study demonstrated the existent role of contingent teacher attention in maintaining a preschool child's aggression to his peers, as well as an imposed use of contingent teacher attention to increase his low peer interaction. Aggression and peer interaction were analyzed independently as two baselines of multiple baseline design; each was subjected to at least one reversal. The multiple baseline design was used to examine three possibilities: (1) that the high rate of aggressive behavior was in itself impeding the emergence of peer interaction; (2) that contingent teacher attention could be used to maintain a reduced rate of aggressive behavior; and (3) that a similar use of teacher attention could maintain an increased rate of peer interaction. The technique of largely ignoring the subject's aggressive behavior and attending instead to whatever child he was attacking decreased his aggressive behavior to an acceptable rate. Two reversals of this technique displayed experimental control, each recovering the high baseline rate of aggression. After the aggressive behavior was decreased for the final time, teachers attended to the subject only when he was involved in social interaction with peers, and they thus increased his social interaction to a high rate. Later, they withdrew their attention for social interaction and reversed the effect and finally then recovered it.

Prognosis in Patients with Transient Ischemic Attacks

Abstract: The prognosis on 144 patients with transient ischemic attacks was determined over a minimum period of three years by quantitating, at intervals, the number of attacks and also the neurological disability by means of a disability score. No patients had neurological disability at the initiation of the study. Total cervicocephalic angiography was performed on 93 patients. Seven of the 144 patients were deceased at the end of the three-year period, five of them due to strokes. Seventeen patients (15.6%) developed persistent neurological disability during the three years, with the mean disability score being much higher for the patients with carotid attacks than those with basilar attacks. The cumulative number of attacks in both carotid and basilar groups rose steadily in the first 18 months, with a much larger number of attacks occurring in the basilar group. The attack rate leveled off after 18 months in the carotid group. Attacks tended to be consistent in nature over a period of time. Twenty-eight percent of those patients with basilar attacks and 12.5% of those patients with carotid attacks showed carotid stenosis on angiography. Study of carotid stenosis associated with subsequent neurological disability revealed that increased risk occurred only when carotid stenosis was more than 70%

Alteration of cortical and reticular acetylcholine release by ethanol in vivo

Abstract: The effect of ethanol on spontaneously released acetylcholine (ACh) was studied in rabbits with cortical collecting cups and push-pull cannulas. The investigation was designed to examine the possibility that behavioral depression produced by acute doses of ethanol is the consequence of impaired central cholinergic transmission. Spontaneously released ACh was collected in Locke's solution, containing physostigmine, held in acrylic cups over the parietal cortex of unanesthetized but immobilized rabbits during consecutive 15-minute periods. Ethanol, 0.5, 1.0 and 2.0 g/kg, was injected i. v. after appropriate control collections. Samples were assayed for ACh by comparing the contractions produced by the samples on a dorsal leech muscle with those produced by standard ACh chloride solutions. For subcortical collection of ACh, a push-pull cannula placed in the mesencephalic reticular formation was used in a similar manner. Ethanol, 1.0 and 2.0 g/kg i. v., depressed, in a dose-dependent manner, the amount of ACh that was collected from the parietal cortex and mesencephalic reticular formation. The site of perfusion within the reticular formation was more sensitive to ethanol depression than the parietal cortex, since the 0.5 g/kg dose of ethanol, unlike its effect on the cortex, significantly decreased free ACh in the reticular formation and produced synchrony of the reticular electroencephalogram. In separate experiments in rats, ethanol, 4.5 g/kg p.o., increased total brain ACh and produced blood ethanol concentrations similar to those produced by an oral dose of ethanol that depressed free cortical ACh in rabbits. The results show that ethanol can depress the release of free ACh in selected areas of the cortex and reticular formation in rabbits. The depressed release may contribute to the acute behavioral intoxication produced by ethanol.

Computer Classification of Reservoir Sandstones

Abstract: A procedure is developed to extract numerical features which characterize the pore structure of reservoir rocks. The procedure is based on a set of descriptors which give a statistical description of porous media. These features are evaluated from digitized photomicrographs of reservoir rocks and they characterize the rock grain structure in term of (1) the linear dependency of grey tones in the photomicrograph image, (2) the degree of "homogeneity" of the image and (3) the angular variations of the image grey tone dependencies. On the basis of these textural features, a simple identification rule using piecewise linear discriminant functions is developed for categorizing the photomicrograph images. The procedure was applied to a set of 243 distinct images comprising 6 distinct rock categories. The coefficients of the discriminant functions were obtained using 143 training samples. The remaining (100) samples were then processed, each sample being assigned to one of 6 possible sandstone categories. Eighty-nine per cent of the test samples were correctly identified.

An adaptive array for interference rejection

Abstract: An adaptive array that rejects undesired or interfering signals is presented. The array pattern is controlled by an adaptive feedback system based on a steepest descent minimization of mean-square error. Error is defined as the difference between the array output and a locally generated reference signal. Minimization of mean-square error is closely related to maximization of signal-to-noise ratio (SNR). A two-element adaptive array has been built, and its experimental performance is discussed. Typical patterns for various desired and interfering signals are shown, as well as measured transient response. Finally, some experiments showing the array behavior with modulated signals are described. The results show that such an antenna system is capable of automatically rejecting interfering signals, subject only to certain basic constraints. No a priori information about the angles of arrival of the signals is required, Detailed knowledge of the waveforms of the desired and interfering signals is also not needed, although the spectral characteristics of the desired signal must be known.

The modification of sentence structure and its relationship to subjective judgements of creativity in writing1

Abstract: The present study objectively defined and manipulated some compositional variables in 10-sentence stories written by fourth-, fifth-, and sixth-grade students, and related these operationally defined variables to subjective judgements of creativity. Points, exchangeable for candy and extra recess, were given to members of two teams contingent upon their using different adjectives, different action verbs, and different sentence beginnings. The students' use of these selected parts of speech was modified and the independent subjective ratings indicated that stories written during contingency conditions were generally rated as more creative than those written during baseline conditions. Operational definitions that specify non-repetition or variety of responses, and contingencies that require response diversity may provide a beginning basis for defining writing creativity and the conditions that maximize its occurrence.

Ultraviolet differences between the Sulphur Butterflies, Colias eurytheme and C. philodice, and a possible isolating mechanism.

Abstract: Two common North American “sulphur” butterflies, Colias eurytheme and C. philodice, hybridize widely over much of the United States. The planting of dense agricultural stands of larval foodplants, together with habitat destruction starting about 1850, are believed to have affected the species' geographical ranges and abundances, causing extensive sympatry over much of the eastern United States1, setting the stage for introgression. Taxonomists have tried to separate the species on the basis of visible wing coloration, but this varies continuously from orange (pure eurytheme) through yellow–orange (eurytheme and many hybrids) to yellow (philodice and rarely eurytheme). Female polymorphism and numerous described infraspecific taxa compound the taxonomic confusion. Although some of this variation has been attributed to genetic (refs. 2 (and references therein) and 3) and environmental factors4, species determinations are often guesswork. We wish to point out two correlated qualitative characters that can be used to separate these species. One character, ultraviolet reflexion, may be more than a taxonomic tool—it may be the butterflies' own carte de visite.

An analysis of individual differences in generalization between receptive and productive language in retarded children.

Abstract: Retarded subjects were taught generative pluralization rules concurrently in both the receptive and productive modalities of language. Receptive training established correct pointing to either one or a pair of objects, in response to a spoken singular or plural label of the object(s); productive training established correct spoken labels of one or a pair of objects presented visually. However, these pluralization rules were established in each modality only for a specific class of plurals: those ending in -s for one modality, those ending in -es for the other modality. This training was successful in establishing generative, or rule-governed behaviors, such that untrained examples of singulars and plurals were usually responded to correctly. Nevertheless, despite this concurrent, generative behavior, probes revealed little generalization between modalities: three of four subjects did not generalize clearly from receptive training with one class of plurals to correct productive use of that class, nor did they generalize from productive training of the other class of plurals to correct receptive response to that class. The fourth subject, however, did show strong generalization of both these types. It was concluded that automatic generalization between receptive and productive language is not necessarily an inevitable result of language training in such subjects, and therefore may require explicit, if temporary, programming, such as by direct reinforcement.

Electrical activity of the intestine of mice with hereditary megacolon and absence of enteric ganglion cells.

Abstract: Mice with a recessive gene which reduces the number of ganglion cells of the large intestine and produces megacolon similar to Hirschsprung's disease were studied. Electrical activity of the small bowel consisted of electrical slow waves and action potentials and showed no difference between the mice with megacolon and their normal siblings. Electrical slow waves and action potentials occurred in the large intestine of both normal and abnormal mice. The principal difference between normal mice and their abnormal siblings was increased incidence of discharge of action potentials associated with uncoordinated phasic contractions superimposed upon tonic contracture of the circular muscle layer of the distal aganglionic segment in the abnormal mouse. The distended colon of the abnormal mouse and the entire length of the normal bowel showed bursts of action potentials which accompanied peristaltic waves of circular muscle contraction. During propulsive motility in the rectum, activation of the circular muscle was preceded by coordinated contraction of the longitudinal muscle only in the normal bowel. Symptoms of megacolon can be accounted for by the absence of spontaneously active inhibitory neurons from the enteric plexuses of the distal segment of the large bowel.

Timeout as a punishing stimulus in continuous and intermittent schedules

Abstract: The effectiveness of a brief period of isolation (timeout) in the control of disruptive behavior emitted by a retarded child in a preschool classroom setting was examined. Timeout was shown to be an effective punishing stimulus, and its control of the child's disruptive behavior was investigated under four schedules of intermittent timeout. The results suggest that as a larger percentage of responses were punished, a greater decrease in the frequency of that response occurred. This inverse relationship between the percentage of responses punished and the frequency of the response did not appear to be linear, but rather a non-linear function. This function suggests that some schedules of intermittent punishment may be as effective as continuous punishment, at least in the case of the continued suppression of a response that has already been reduced to a low frequency.

Delineation by lanthanum staining of filamentous elements associated with the surfaces of axonal microtubules.

Abstract: SUMMARY The major formed elements of axons of the ventral nerve cord of the crayfish are longitudinally oriented microtubules, filamentous matrix material, and mitochondria. Lanthanum staining delineates both microtubules and filamentous material to great advantage, and it is demonstrated that filamentous elements continuous with matrix material are associated with the surfaces of microtubules. Microtubules are interconnected by filamentous elements and connexions also exist between microtubules and the plasma membrane to form a 3-dimensional latticework. This latticework is hypothesized to play a role in translocation of materials down the axon: the filamentous material probably provides the gelatinous integrity of the axoplasm and may provide the motive force for axonal transport, with the microtubules serving as attachment sites and guideways extending the length of the axon. In pieces of nerve cord treated with cytochalasin B, the filamentous material of the axoplasm is structurally unchanged. Treatment of pieces of nerve cord with hyaluronidase, however, induces the formation of large tubular elements (macrotubules), 40-50 ran in diameter, with which lateral filamentous material is also associated.