Showing papers by "University of Virginia published in 1979"

Usable Knowledge: Social Science and Social Problem Solving

Abstract: An agenda of basic questions about the impact of social science and research on real life problems. How social scientists are often crippled by a misunderstanding of their own trade.

Lectures on Ethics

Abstract: Introduction J. B. Schneedwind Part I. Kant's Practical Philosophy: 1. Herder's lecture notes (selections) Part II. Moral Philosophy: 2. Collins's lecture notes Part III. Morality According to Professor Kant: 3. Mrongovius's second set of lecture notes (selections) Part IV. Kant on the Metaphyscics of Morals: 4. Vigilantius's lecture notes.

Sources of subcortical projections to the superior colliculus in the cat.

Abstract: A comprehensive search for subcortical projections to the cat superior colliculus was conducted using the retrograde horseradish peroxidase (HRP) method. Over 40 different subcortical structures project to the superior colliculus. The more notable among these are grouped under the following categories. Visual structures: ventral lateral geniculate nucleus, parabigeminal nucleus, pretectal area (nucleus of the optic tract, posterior pretectal nucleus, nuclei of the posterior commissure). Auditory structures: inferior colliculus (external and pericentral nuclei), dorsomedial periolivary nucleus, nuclei of the trapezoid body, ventral nucleus of the lateral lemniscus. Somatosensory structures: sensory trigeminal complex (all divisions, but mainly the γ division of nucleus oralis), dorsal column nuclei (mostly cuneate nucleus), and the lateral cervical nucleus. Catecholamine nuclei: locus coeruleus, raphe dorsalis, and the parabrachial nuclei. Cerebellum: medial, interposed, and lateral nuclei, and the perihypoglossal nuclei. Reticular areas: zona incerta, substantia nigra, midbrain tegmentum, nucleus paragigantocellularis lateralis, and the hypothalamus. Evidence is presented that only the parabigeminal nucleus, the nucleus of the optic tract, and the posterior pretectal nucleus project to the superficial collicular layers (striatum griseum superficiale and stratum opticum), while all other afferents terminate in the deeper layers of the colliculus. Also presented is information concerning the rostrocaudal distribution of some of these afferent connections. These findings stress the multiplicity and diversity of inputs to the deeper collicular layers, and more specifically, identify multiple sources of the physiologically well-known representations of the somatic and auditory modalities in the colliculus.

Comovements in Stock Prices in the Very Short Run

Abstract: Correlations among price changes in common stocks of companies in one industry are found to decrease with the length of the interval for which the price changes are measured. This phenomenon seems to be caused by nonstationarity of security price changes and by the existence of correlations between price changes in the same stock—and in different stocks—in successive periods. Although such correlations are not necessarily inconsistent with market efficiency, the data do reveal the presence of lags of an hour or more in the adjustment of stock prices to information relevant to the industry.

Generation by insulin of a chemical mediator that controls protein phosphorylation and dephosphorylation.

Abstract: Deproteinized skeletal muscle extracts free of major nucleotides from control and insulin-treated rats were fractionated and assayed for inhibition of protein phosphorylation by cyclic adenosine monophosphate (AMP)-dependent and -independent protein kinases. A differential effect of insulin on a particular fraction was observed on cyclic AMP-dependent protein kinase but not on cyclic AMP-independent protein kinases. This fraction that inhibited cyclic AMP-dependent protein kinase also stimulated glycogen synthase phosphoprotein phosphatase. It is proposed that this fraction may contain a mediator substance generateed in the presence of insulin.

Lanthanides as probes for calcium in biological systems

Abstract: Calcium ion plays an essential role in many biological processes. The environment about Ca2+ may be probed by substitution of tripositive lanthanide ions, Ln3+. Ca2+ proteins fall into two broad classes: those that are inhibited by Ln3+ substitution and those that are not. It is suggested that although Ca2+ undertakes a primarily structural role in the Ln3+ non-inhibited proteins, Ca2+ may be near the active site or participate in the mechanism of action of Ln3+ inhibited proteins. Ca2+ and Ln3+ radii are similar; most Ln3+ are slightly larger than Ca2+ in complexes of the same coordination number, and substitution of Ln3+ for Ca2+ is accommodated by a slight decrease in bond distance or by an increase in coordination number. Luminescence from Tb3+ has been demonstrated to be a sensitive environmental probe of Ca2+ binding sites in proteins.

Play and Social Interaction in Children Following Divorce

Abstract: This paper presents the results of a longitudinal study of the effects of divorce on play and social interaction in children. Forty-eight middle class white preschool children from divorced families and a matched group of forty-eight non divorced families were studied at 2 months, 1 year and 2 years after divorce. In the first year following divorce disruptions were found in both play and social relations for boys and girls from divorced families. The adverse effects had largely disappeared for girls by two years after divorce; however, the effects were more intense and enduring for boys. The play patterns of children from divorced families, in comparison to those of children in non divorced families, were less socially and cognitively mature when measured shortly after divorce. Limitations and rigidity in fantasy play were particularly notable. In the year following divorce both boys and girls showed high rates of dependent helpseeking behavior and acting out, non-compliant behavior. This again was more enduring in boys than girls. Even when the behavior of boys from divorced families had improved they were viewed and responded to more negatively by peers and teachers than were children from non divorced families or girls from divorced families.

Attachment as Related to Mother-Infant Interaction

Abstract: Publisher Summary Infant-mother attachment is conceived as an affectional tie that a baby forms to his mother figure, binding them together in space and enduring over time; such bonding is not present at birth, but develops during the first year of life. This chapter provides an overview of individual differences in attachment and attachment behavior as they are related to differences in maternal behavior in interaction with the infant. Although, the infant through his own idiosyncratic patterns of behavior, contributes to the interaction with his mother; however, the extent to which his mother goes along with, disregards, or opposes the implications of the baby's behavioral cues makes a great deal of difference to the quality of the interaction. To the extent that it is the mother's contribution that emerges as the more important, it can be expected that information, advice, training, and or intervention might assist mothers to adopt practices likely to facilitate normal infant development. The chapter acknowledges that changes in the behavior of one partner may at some particular stage of the infant development and in regard to some specific aspect of mother-infant interaction trigger changes in the behavior of the other.

Redistribution of thallium at rest in patients with stable and unstable angina and the effect of coronary artery bypass surgery.

Abstract: To determine the significance of redistribution (RD) of thallium-201 (/sup 201/T1) at rest in patients with coronary artery disease, 14 patients with unstable angina (UA) and 15 patients with stable angina (SA) referred for angiography underwent serial myocardial /sup 201/T1 imaging over 3 hours. No patients were imaged during pain. Anterior and left anterior oblique images were divided into six segments for analysis. The extent of coronary artery disease and the /sup 201/T1 perfusion pattern were similar for UA and SA patients. In the 29 patients, 91 of 174 segments had decreased /sup 201/T1 uptake on the 10-20-minute images. At least one initial defect was present in 26 of 29 patients, but only 14 of 29 had ECG evidence of infarction. On delayed 3-hour images, 69 of 91 segments with diminished initial uptake showed RD, while 22 defects persisted. Angiography demonstrated that 66 of 69 segments with RD had significant (> 70%) corresponding coronary artery stenoses. Wall motion analyses of 63 segments with RD revealed that 52 were normal or hypokinetic and 11 were akinetic or dyskinetic. Of 13 persistent defects, six were normal or hypokinetic and seven akinetic or dyskinetic (p > 0.02). In 22 patients who underwent coronarymore » bypass surgery, 37 of 48 segments (77%) with decreased initial /sup 201/T1 uptake and subsequent RD preoperatively reverted toward normal initial uptake postoperatively. In addition, 13 of 18 persistent defects preoperatively showed /sup 201/T1 uptake postoperatively.Thus, resting /sup 201/T1 defects may not represent myocardial scar. Patients with UA or SA may show RD of /sup 201/T1 at rest. Myocardial revascularization is usually associated with improvement in early /sup 201/T1 uptake in segments with initial defects and RD preoperatively.« less

Effects of stem density upon sediment retention by salt marsh cord grass, Spartina alterniflora loisel

Abstract: A laboratory experiment was conducted to determine whether retention of waterborne sand by salt marsh cordgrass, Spartina alterniflora Loisel, is directly related to the number of stems per unit area. Waves generated in a trough washed over a sloping beach planted with S. alterniflora sprigs: a range of stem densities (0–108 stems/m2) was examined in separate trials. The amount of sand accumulated after 60 waves is a positive nonlinear function of stem density. The greatest accretion coincided with the highest stem density tested. Shape of the beach profile was also strongly influenced by the number of stems per m2.

Afferent influences on the development of the brain stem auditory nuclei of the chicken: Otocyst ablation

Abstract: The effects of embryonic deafferentation on the morphological development of the avian cochlear nuclei, n. angularis (NA) and n. magnocellularis (NM), were investigated. The right otocyst was surgically removed from chick embryos at 55 to 60 hours of incubation and the subsequent development of total volume, neuron number, and neuron cross-sectional area were studied with quantitative methods in animals sacrificed at 2-day intervals between embryonic days 9 and 19 and at 28 days posthatching. The development of NA and NM is severely affected by otocyst ablation. Between embryonic days 9 and 19, a large group of NA neurons in the medioventral portion of the nucleus on the perated side moves to an ectopic ventromedial position, while the remainder of this nucleus stays in its normal dorsolateral position. Beginning about day 13 of incubation, the normal increase in the volume of NA and the size of its neurons becomes progressively retarded and 40% of its neurons are lost. The growth of NM is also retarded after day 11 of incubation and the growth of mean neuron size is retarded after day 15. There is a 30% loss of neurons in NM which begins after embronic day 11. The results indecate the primary cochlear fibers make a critical contribution to the growth and maintenance of their target neurons. The absence of this facilitative influence following otocyst ablation becomes apparent just at the time synapses would normally be formed between the promary auditory afferents and the brain stem auditory neurons. The abnormal movement of neurons in nucleus angularis to an ectopic position after otocyst ablation suggests that primary auditory afferents may serve to stabilize the position of their target cells within the developing brain.

A General ANOVA Method for Robust Tests of Additive Models for Variances

Abstract: Linearly combining Levene's z 2 variable with the jackknife pseudo-values of s 2 produces a family of variables that allows for analysis of variance (ANOVA) tests of additive models for the variances in fixed effects designs. Some distributional theory is developed, and a new robust homogeneity of variance test is advocated.

Gas dynamics in barred spirals: Gaseous density waves and galactic shocks

Abstract: Steady-state gasdynamical studies, previously limited to tightly wound normal spiral galaxies, are extended to models of barred spirals with a 5% to 10% perturbing potential. The models show that a strong wave manifestation is an important constituent of the bar structure in many barred spirals and that a density-wave shock wave can form a bar structure as pronounced as the narrow bars often evident in optical photographs of barred spirals. The dark narrow dust lanes often observed along the leading edges of bar structures are identified as tracers of shocks, and it is found that strong shocks along a bar structure during even a small part of a galaxy's lifetime might easily deplete a large enough proportion of the gas to cause a lack of gas in the inner annuli encompassing the bar by the time of the present epoch. It is emphasized that even moderate-amplitude barlike perturbations in the disk can drive large noncircular gas motions, typically 50 to 150 km/s.

Organization and Development of Brain Stem Auditory Nuclei of the Chicken: Dendritic Gradients in Nucleus Laminaris

Abstract: Nucleus laminaris (NL) is a third-order auditory nucleus in the avian brain stem which receives spatially-segregated binaural inputs from the second-order magnocellular nuclei The organization of dendritic structure in NL was examined in Golgi-impregnated brains from hatchling chickens Quantitative analyses of dendritic size and number were made from camera lucida drawings of 135 neurons sampled from throughout the nucleus The most significant results of this study may be summarized as follows: (1) The preponderant neuron in n laminaris may be characterized as having a cylindrical-to-ovoid cell body, about 20 micrometer in diameter The neurons comprising NL were found to be nearly completely homogeneous in issuing their dendrites in a bipolar fashion: one group of dendrites is clustered on the dorsal surface of the cells, the other group on the ventral The dendrites of NL are contained within the glia-free neuropil surrounding the nucleus From the rostromedial to the caudolateral poles of NL there is a gradient of increasing extension of the dendrites, increasing number of tertiary and higher-order dendrites, and increasing distance from the somata of the occurrence of branching (2) The total dendritic size (sum of the dorsal) and ventral dendritic lengths of the cells) increases 3-fold from the rostromedial to the caudolateral poles of NL About 50% of the variance in dendritic size is accounted for by the position of the cells in NL, and the gradient of dendritic size increase has the same orientation across NL as the tonotopic gradient of decreasing characteristic frequency in NL (3) From the rostromedial pole to the caudolateral pole of NL there is an 11-fold decrease in the number of primary dendrites along a gradient coinciding with the length and frequency gradients Sixty-six percent of the variance in dendrite number is accounted for by position in the nucleus (4) The correlation of dorsal and ventral dendritic size on a cell-by-cell basis is not high (r = 047), indicating a fair amount of variability on the single-cell level On the other hand, the average dorsal dendritic length within an isofrequency band in NL correlates very highly with the average ventral dendritic length Thus, on an areal basis, the amount of dendritic surface area offered to the dorsal and ventral afferents is tightly regulated (5) The dorsal and ventral dendrites have separate gradients of increasing length and number across NL The dorsal gradients are skewed toward the rostrocaudal axis, while the ventral dendritic gradients are skewed mediolaterally (6) There was no correlation between either dendritic size or number of primary dendrites and the size of the somata in NL, which remains relatively constant throughout the nucleus Several hypotheses about the ontogenetic control of dendritic structure are examined in light of the above data Of these, the hypotheses that the ontogeny of dendritic size and number is largely under afferent control receives a great deal of circumstantial support

Development of cell types and of regional differences in the postnatal rat epididymis.

Abstract: The development of cell types and regional differences in the rat epididymis was studied in specimens of the initial, middle and terminal segments prepared at intervals between birth and postnatal day 94. The development of the epididymis was divided into three phases: (1) an undifferentiated period; (2) a period of differentiation, and (3) a phase of expansion. During the undifferentiated period, from birth to day 15, the epithelial cells had a uniform appearance. Halo cells, which are believed to be migratory leukocytes, appeared on day 14. The period of differentiation extended from day 16 to day 44. Slender, densely staining cells, termed narrow cells, appeared in the epithelium of all three segments on day 16, constituting the first evidence of differentiation of cell types in the epididymal epithelium per se. In addition to their shape and apical nuclei, the narrow cells were distinguished from other epithelial cells by the presence of cup-shaped apical vacuoles and mitochondria with tubular cristae. Principal cells and basal cells were identified on day 28, which also marked the firsh distinction of differences in epithelial height among the different segments. Narrow cells persisted into the adult in the initial segment. In the middle and terminal segments, however, narrow cells disappeared by day 35, when light cells made their appearance. The major event of the period of expansion, from day 45 to 3 months, was the appearance of sperm in the lumen between days 45 and 52. A model for differentation of cell types in the epididymis is proposed and it is suggested that narrow cells are precursors to light cells in the middle and terminal segments. The development of ultrastructural features of adult cell types preceded the appearance of sperm in the lumen.

Dilation analyticity in constant electric field

Abstract: The resolvent of the operatorH0(e, θ)=−Δe-20+ex1eθ is not analytic in θ for θ in a neighborhood of a real point, if the electric field e is non-zero. (One manifestation of this singular behavior is that for 0<|Im θ|<π/3,H0(e, θ) has no spectrum in the finite plane.) Nevertheless it is shown that the techniques of dilation analyticity still can be used to discuss the long-lived states (resonances) of a system described by a Hamiltonian of the formH=−Δ+ex1+V(x).

Culture of early somite mouse embryos during organogenesis

Abstract: Early somite (2-4) mouse embryos were explanted and then maintained in culture for 24 or 48 h intervals. Various types of media were tested and it was determined that rat serum supported normal growth over a period of 48 h, based on total protein analysis and histological comparisons with in vivo specimens. Other media including fetal calf serum and fetal calf serum and Waymouth's (1:1) supported some growth, but did not equal the success of using rat serum alone. During the 48 h culture period in rat serum, embryos developed to stages indistinguishable from embryos maintained for a similar time in vivo.

Species-Specific Resistance to Antimicrobial Synergism in Streptococcus faecium and Streptococcus faecalis

Abstract: Combinations of penicillin with various aminoglycosidic aminocyclitols were tested against a collection of clinical isolates of Streptococcus faecium in vitro and were used to treat endocarditis caused by S. faecium in the rabbit model. S. faecium proved more resistant to penicillin than Streptococcus faecalis. Even more striking, however, was the resistance to in vitro synergism by combinations of penicillin and various aminoglycosides. At clinically achievable concentrations, penicillin-gentamicin was the only combination that was synergistic against all strains that were tested. Combinations of penicillin and streptomycin and penicillin and amikacin were synergistic only against those strains that were not highly resistant to streptomycin and kanamycin, respectively. Combinations of penicillin with kanamycin, tobramycin, sisomicin, or netilmicin failed to produce synergism against any of these strains. The possible clinical significance of these findings was verified by use of the rabbit model of endocarditis. Combinations of penicillin with gentamicin or streptomycin were synergistic in the therapy of endocarditis that was produced by a strain of S. faecium that did not have a high level of resistance to aminoglycosides. However, the combination of penicillin and netilmicin was no more effective than penicillin alone.

Coronary-prone behavior pattern, task incentive, and cardiovascular response.

Abstract: In this experiment it was predicted that the presence or absence of a performance-contingent incentive (monetary reward) would mediate effects of the coronary-prone behavior pattern on behavioral and cardiovascular responses to a difficult cognitive task. Accordingly, 44 subjects of the Type A (coronary-prone) and Type B (non-coronary-prone) behavior patterns were assigned to one of two task conditions, labelled Incentive and No Incentive. Results indicated that under No Incentive Type As performed better at the experimental task and reported less state anxiety than Type Bs, whereas in the Incentive condition, Type A and B subjects showed no differences in task performance or self-report of anxiety. Concerning cardiovascular measures, analysis of variance revealed significantly greater systolic blood pressure and pulse pressure elevations for Type A than Type B subjects, but showed no reliable interactions of the Type A, B and Incentive factors nor any related effects regarding heart rate or diastolic blood pressure. Individual differences in subjects' scores on the inventory for coronary-prone behavior pattern, however, correlated positively with heart rate accelerations in the No Incentive condition, but did not covary with heart rate changes under Incentive. With respect to subjects' perceptions of the task, self-report data suggested that Type As responded in a more active and involved manner and resisted feelings of helplessness to a greater extent than their Type B counterparts.

Single‐fiber electromyography in myasthenia gravis

Abstract: One-hundred-sixty single-fiber EMG studies of the extensor digitorum communis muscle were performed on 127 patients with myasthenia gravis; 131 demonstrated defective neuromuscular transmission. Jitter determinations in the biceps, deltoid or frontalis muscles increased the diagnostic yield significantly. Evoked-potential EMG studies were abnormal in less than 50 percent of patients in whom they were performed. The most sensitive criterion of abnormality was the percentage of fibers with increased jitter; the sensitivity of the test was enhanced, however, if the mean jitter of the tested muscle was also used as a criterion of abnormality. Since increased jitter may also be seen in primary muscle and nerve disease, these disorders must be excluded by other means before diagnosing myasthenia gravis on the basis of the single-fiber studies.

Aspirating culture catheter and method of use

Abstract: A catheter adapted to be introduced into a body cavity, such as a bronchial tube or lung, and a method of using the catheter. The catheter consists of inner and outer concentric tubes having a reflected cylindrical membrane attached adjacent their distal ends. Pressurized fluid may be introduced through the perfusate passage running between the tubes and thus between the walls of the reflected membrane in order to provide relative rigidity for the membrane and to seal the reflected end of the membrane, thereby creating a closed pristine chamber, defined by the walls of the reflected membrane about the end of the inner tube. A cage composed of balls mounted on resilient pins may be disposed within the reflected membrane to aid the reflection of the membrane. A portion of the reflected membrane may be perforate. Following introduction of the catheter into a bronchial tube in the method of the invention, the inner tube is extended to open and pass through the reflection, thereby rolling the inner wall about the reflected portion and reversing the inner walls of the pristine chamber. Optionally, a topical antibiotic or local anesthetic may be introduced into the membrane and extruded through the perforations during the introduction or exit, or a lung brush or other sampling means may be inserted through the lumen of the inner tube during use. The catheter may also be used for endotracheal intubation.

Stupor following administration of valproic acid to patients receiving other antiepileptic drugs.

Abstract: Stupor is an unusual complication following the addition of valproic acid to other antiepileptic drugs. We report four such cases. Stupor occurred acutely in 3 patients and insidiously in the fourth. In the cases of acute toxicity, neither toxic levels of valproate nor significant elevations in blood levels of the other drugs occurred. In the fourth patient, stupor occurred concomitantly with a rise in the phenobarbital level. The electroencephalograms of all 4 patients revealed generalized high-amplitude rhythmic bisynchronous delta activity. Recovery occurred following discontinuation of valproic acid or other antiepileptic drugs. These observations suggest that stupor may occur as a result of drug interactions after the addition of valproic acid to other antiepileptic drugs.