Showing papers by "Indiana University published in 1978"

Product formulas and numerical algorithms

Abstract: Product formulas constitute one of several bridges between numerical and functional analysis. In numerical analysis, they represent algorithms intended to approximate some evolution equation and, in functional analysis, they are used to prove estimates, existence and representation theorems. Our aim is to survey the setting for product formulas and to discuss some recent results. Needless to say, we do not attempt to accommodate all the complex variations which occur in practical algorithms, nor the sharpest possible theoretical results. Nevertheless, we hope that our middle ground approach and some of the examples will be of interest to both groups. Because of its survey nature, we have not hesitated to include some well-known examples which are important for understanding the ideas. The general idea of product formulas is the following. Suppose one is interested in an initial value problem

Thermodynamical Proof of the Gibbs Formula for Elementary Quantum Systems

Abstract: An elementary derivation is given of the formula for the thermal equilibrium states of quantum systems that can be described in finite-dimensional Hilbert spaces. The three assumptions made, Passivity, Structural Stability, and Consistency, have phenomenological interpretations. Except at zero temperature, Structural Stability follows already from Passivity and a weak form of Consistency.

Long term effect of Cis‐Diamminedichloride platinum (CDDP) on renal function and structure in man

Abstract: To examine CDDP induced nephrotoxicity in patients with testicular carcinoma, we measured renal function prior to therapy and at six month intervals for twelve months in fifteen patients and twenty-four months in seven patients. CDDP was given iv at 20 mg/M2 per day for five days at three week intervals. Eight patients received three courses, four received four courses and three received more than four courses. The mean creatinine clearance +/- SD prior to treatment was 112 +/- 12 ml/min. By six months, it had decreased to 68.5 +/- ml/min (p less than 0.01) and it remained at that level. Plasma creatinine and blood urea nitrogen increased significantly. Subjects receiving other potential nephrotoxins in addition to CDDP developed a greater decrease in creatinine clearance (p less than 0.05). Proteinuria and functional tubular disturbances were not observed. Microscopic features were characterized by hydropic degeneration of the renal tubular epithelium, thickened tubular basement membranes and mild interstitial fibrosis. Electron microscopy revealed phagolysosomes filled with flocculent material. CDDP resulted in a permanant, nonspecific renal injury in our patients. Although the renal injury has remained subclinical, future courses of CDDP may lead to clinically important chronic renal failure.

The response of arginine vasopressin to intravenous ethanol and hypertonic saline in man: the impact of aging.

Abstract: The effect of age on the hypothalamic-hypophyseal-renal axis in normal man was determined by assaying plasma arginine vasopressin (AVP) responses to inhibitory and to secretory stimuli. Nine young (21-49 years) and 13 old (54-92 years) subjects received IV ethanol (375 mg/m2 per min). AVP levels fell progressively during the infusion in the young group, but fell for only 30 min in the old group and then rose paradoxically despite the continuing increase in blood ethanol. Eight young (22-48 years) and 8 old (52-66 years) men were provided identical osmolal loads by a 2-hour IV infusion of 3% NaCl at 0.1 ml/kg per min. Serum AVP rose 2.5 times the baseline in the young and 4.5 times the baseline in the old men despite identical free water clearances. Osmoreceptor sensitivity (the slope of AVP on osmolality) was greater in the old subjects. The heightened sensitivity to hyperosomolality helps examine the paradoxical response to ethanol, since osmolality increased during that time. This increased AVP response may severe to compensate for the reduced renal ability to conserve salt and water in aging man.

Huddling by Rat Pups: Group Behavioral Mechanisms of Temperature Regulation and Energy Conservation

Abstract: Body heat loss was attenuated and oxygen consumption was reduced by huddling in litters of developing rats. Rat pups derive physiological benefits from huddling similar to those enjoyed by adult mammals; these findings contrast with previous characterizations of the altricial rat as poikilothermic. Huddling insulates by lessening the exposed body surface area of the participants, thus retarding heat loss and enhancing the efficiency of thermogenesis . These physical mechanisms of the clump are actively regulated by the pups. A novel quantitative measure of huddle size revealed a form of group regulatory behavior in rat pups whereby the surface expanded and contracted with increases and decreases in ambient temperature. The individual basis of this group regulatory activity was investigated by marking individual pups and observing them in huddles by means of time-lapse videography. It was found that individual animals circulate through the huddle, frequently exchanging locations in the group. By studying the huddle positions of an anesthetized pup and a marked control sibling, dynamics of the pup flow were clarified. Ordinarily, the direction of movement was actively downward, into the pile; immobile pups "floated" on the surface. When the nest temperature was raised to thermoneutral, the direction of pup flow reversed and an immobile animal sank to the depths of the huddle. Through individual competitive adjustments the huddle behaves as a self-regulating unit which provides warmth and insulation to all its active members.

New antiarrhythmic agents: amiodarone, aprindine, disopyramide, ethmozin, mexiletine, tocainide, verapamil.

Abstract: The present status, clinical experience, side effects, clinical pharmacology and electrophysiologic actions of seven new antiarrhythmic agents are reviewed. The drugs selected for comment are amiodarone, aprindine, disopyramide, ethmozin, mexiletine, tocainide and verapamil. Each drug has been shown to have clinical efficacy in suppressing cardiac arrhythmias.

Asymptotic Completeness for Quantum Mechanical Potential Scattering

Abstract: A new (geometrical) proof is given for the asymptotic completeness of the wave operators and the absence of a singular continuous spectrum of the Hamiltonian for potentials which decrease faster than in the Coulomb case, the space dimension is arbitrary.

Observer Agreement and Reliabilities of Classroom Observational Measures

Abstract: There appears to be a growing interest in the study of process variables in naturalistic classroom settings. Numerous observation systems have been developed and used in such investigations (Simon & Boyer, 1974). However, there is a corresponding paucity of published research that documents relationships between teaching-learning processes and educationally relevant pupil outcomes (Dunkin & Biddle, 1974; Heath & Nielson, 1974; Rosenshine, 1971; Smith, 1971; Soar, 1972). A reason for many insignificant findings may be that investigators have inadequately controlled or accounted for a number of sources of variance associated with observational studies (McGaw, Wardrop, & Bunda, 1972). The purpose of this paper is to clarify a number of common methodological errors made in observational studies and then to suggest practical means of minimizing such errors. Of primary concern are those errors introduced by observers and investigators that can limit reliabilities of observational measures. Prevalent confusion concerning the reliabilities of observational measures can be traced to the failure to separate two statistically related

The Sex-Stereotyping of Musical Instruments:

Abstract: This series of studies was undertaken to examine musical instrument gender associations. Study 1, which investigated adult musical instrument preferences for children, indicated significant differences (<.05) in instrument selections due to the sex of the child. Study 2 employed a paired-comparison strategy to place eight instruments under investigation on a masculine-feminine continuum. Study 3 investigated children's (K-5) instrumental preferences. Results showed a significant sex by grade interaction. Study 4 examined three procedures for presenting the instruments to preschool children. The results showed a significant sex by method of presentation interaction.

Limit theorems for sums of dependent random variables occurring in statistical mechanics

Abstract: We study the asymptotic behavior of partial sums S nfor certain triangular arrays of dependent, identically distributed random variables which arise naturally in statistical mechanics. A typical result is that under appropriate assumptions there exist a real number m, a positive real number λ, and a positive integer k so that (S n−nm)/n1−1/2k converges weakly to a random variable with density proportional to exp(−λ¦s¦ 2k/(2k)!). We explain the relation of these results to topics in Gaussian quadrature, to the theory of moment spaces, and to critical phenomena in physical systems.

The Development of the Full Passive.

Abstract: Spontaneous full passives and related constructions from 234 children aged 2; 0 to 13; 11 and elicited passives from 262 college students were analysed. Full passives were classified as REVERSIBLE (The dog was chased by the girl), INSTRUMENTAL NON-REVERSIBLE (The lamp was broken by (or with) the ball), or AGENTIVE NON-REVERSIBLE (The lamp was broken by the girl). The Agentive non-reversible did not appear until after age 9; and until age 11 no child produced both Reversible and Non-reversible passives. All the children used the passive in a semantically restricted way (but not in the same way). The possible developmental course of the full passive was traced for children who initially used only Reversible passives versus those who initially used only Instrumental non-reversible passives.

“Opportunity” and “willingness’ as ordering concepts in the study of war

Abstract: (1978). “Opportunity” and “willingness’ as ordering concepts in the study of war. International Interactions: Vol. 4, No. 4, pp. 363-387.

Huddling by rat pups: multisensory control of contact behavior.

Abstract: Huddling, or clumping behavior, begins in the litter situation and persists throughout the adult life of the rat (Rattus norvegicus). In pups, as in adults, the behavior provides a metabolically important means of reducing heat loss. The sensory stimuli that elicit, direct, and maintain huddling in developing rat pups (5-20 days of age) were studied in a standardized testing situation by using long-term time-lapse video observations. All pups huddled with a single, immobile sibling. A loop of warm tubing also elicited huddline. However, it appears that other, nonthermal cues can elicit huddling, since a dead, ambient-temperature pup was a sufficient stimulus for the behavior. Disruption of normal olfactory input by intranasal infusion of zinc sulfate interfered with the maintenance of contact. In addition, two kinds of tactile stimulus, vertical contours and furry "comfort" cues, as well as photic responses appeared to participate in the mediation of huddling. Huddling in the altricial rat is under multisensory control, although the number of cues used by pups for huddling appears to increase with age.

Hypersensitive Serotonergic Receptors Involved in Clinical Depression—A Theory

Abstract: As many investigators will attest, developing and conducting a research program in the field of mental health is a very difficult task. It is only in the last 20 years that a few hints have appeared in the literature from animal research in the fields of neuropharmacology and neurochemical correlates of behavior that give the researcher any leads on which to base an active clinical-basic research program. These ideas have led to some important clinical studies that will be referred to below. It is interesting that some recent work with animal models of depression has again provided the research clinician with new insights for further experimentation.

The Statistics of Curie-Weiss Models

Abstract: LetSn denote the random total magnetization of ann-site Curie-Weiss model, a collection ofn (spin) random variables with an equal interaction of strength 1/n between each pair of spins. The asymptotic behavior for largen of the probability distribution ofSn is analyzed and related to the well-known (mean-field) thermodynamic properties of these models. One particular result is that at a type-k critical point (Sn-nm)/n1−1/2k has a limiting distribution with density proportional to exp[-λs2k/(2k)!], wherem is the mean magnetization per site and A is a positive critical parameter with a universal upper bound. Another result describes the asymptotic behavior relevant to metastability.

Biochemical Aspects of Transmission at Inhibitory Synapses: The Role of Glycine

Abstract: The biochemical aspects of the neurophysiology of transmission have been clarified during the years since the late 1950s. Thus, it is interesting to recall that during this period many biochemists became aware for the first time that most neurons in the central nervous system of higher vertebrates do not touch. With the aid of the electron microscope, the neuroanatomists have shown that a space of approximately 200 A separates the terminal endings of the axon of one neuron and the cellular membranes of the next neuron. This space is called the synaptic cleft and can vary from 100 to 500 A depending on the tissue and the location; this whole minute region in the nervous system (i.e., the terminal ending of one neuron, the cellular membrane of the second neuron in juxtaposition to the specific nerve ending, and the synaptic cleft) is called a synapse. Various organic compounds can be released from the axonal endings of the presynaptic cell into the synaptic cleft. The compounds which reach and can affect the conductance across the postsynaptic membrane at this region of the synapse in a specific manner are called transmitters and the whole process is called transmission. This latter process is chemical in nature.

A novel method for the isolation and study of a magnetotactic bacterium.

Abstract: The magnetococcus, a magnetotactic bacterium, has been grown in a complex simulated natural environment. Sufficiently pure samples of cells were obtained magnetically making axenic cultures unnecessary for many purposes. The magnetococcus is a Gram-negative coccus, 1.6 micron in diameter and readily distinguished by highly refractile inclusions and its magnetotactic behavior. This organism is actively motile by means of two bundles of flagella. Electron dense ferromagnetic inclusions were localized between the flagellar bundles. Collections of magnetococci were morphologically homogeneous and negligibly contaminated by extraneous bacteria. DNA extracted from pooled collections of cells was homogeneous by analytical CsC1 centrifugation. The guanine-cytosine content was 61.7%. Total iron by percent cellular dry weight was 3.8%. Comparisons with a previously described magnetotactic marine coccus were made.

Comparative Nephrotoxicity of Aminoglycoside Antibiotics in Rats

Abstract: Netilmicin, gentamicin, tobramycin, amikacin, kanamycin, streptomycin, and sisomicin were given daily for 15 days to groups of rats at three dosage levels corresponding to 10, 15, or 25 times the dose recommended for humans on a weight basis. Decreased urinary osmolality and increased urinary excretion of protein and beta-N-acetyl hexosaminidase were dose-related features of nephrotoxicity. Decreased tubular resorption of glucose and phosphate were observed with the most toxic regimens after extensive renal damage had occurred. All aminoglycosides accumulated in renal tissue; however, the concentration of drug in the renal cortex at the time the rats were killed was not useful for the prediction of renal impairment. Streptomycin and netilmicin exhibited a flat dose-reponse curve with respect to histological damage, as compared with the curves for the other drugs. Results of studies of creatinine clearance and examination of renal tissue suggested the following order of increasing toxicity of the treatment regimens: (1) 0.9% NaCl and uninjected controls; (2) streptomycin; (3) netilmicin; (4) tobramycin; (5) sisomicin, amikacin, and kanamycin; and (6) gentamicin.

Toward the assessment of social competence.

Abstract: Two studies directed toward development and validation of a self-report measure of social competence in dating and assertion situations are described. An 18-item questionnaire consisting of items that assessed the likelihood of certain specific behaviors occurring and the degree of discomfort and expected incompetence in specific situations was derived. This questionnaire discriminated between client and normal populations and between clients with dating and assertion problems, has psychometric properties of reliability and validity, and measures differential improvement following a variety of 8-week interVention programs.

Increased CTP synthetase activity in cancer cells.

Abstract: AN insight into the biochemical strategy of cancer cells has been achieved by the conceptual and experimental approach provided by the molecular correlation concept1,2. Studies carried out using this approach with model systems of rat hepatomas and kidney tumours of different growth rates revealed a biochemical imbalance in cancer cells, which manifested itself in progressive changes in activities of key enzymes and overall metabolic pathways that correlated with tumour growth rate1,2. Some of these biochemical alterations have been shown to apply to human primary liver3 and kidney4 carcinomas. Those alterations in gene expression that are linked to the increase in the expression of malignancy are manifested in the increased activities of key glycolytic-, purine-, pyrimidine-, DNA- and polyamine-synthesising enzymes1–8. Concurrently, decreases occur in the activities of the key enzymes of gluconeogenesis, purine and pyrimidine catabolism and of the urea cycle1–5,9,10. In addition to such a progression-linked (growth-rate-linked) metabolic imbalance, the reprogramming of gene expression in cancer cells entails transformation-linked alterations that are present in all hepatomas irrespective of growth rate or extent of differentiation1,2,11–15.Here we report that CTP synthetase (UTP:L-glutamine amido ligase, EC 6.3.4.2) increased in all the hepatomas examined, the activity being highest in the rapidly growing tumours. Thus, in liver neoplasia the activity of this enzyme is both transformation- and progression-linked. CTP synthetase activity was also markedly increased in transplantable kidney tumours in the rat and in primary renal cell carcinomas in man.

Incidence and significance of decreases in systolic blood pressure during graded treadmill exercise testing.

Abstract: The incidence of decreases in peak systolic blood pressure during treadmill exercise was investigated in 460 patients with definite or suspected coronary heart disease. All patients were studied with coronary cineangiography. Exercise was continued to one of the following end points: chest pain, 85 to 90 percent of the patient's age-predicted maximal heart rate, ventricular tachycardia or a sustained decrease of 10 mm Hg or more below the peak level of systolic blood pressure. Twenty-two patients with 75 percent or greater stenosis of one or more major coronary arteries manifested a decrease in systolic pressure 10 mm Hg or more during exercise. These included 15 (17 percent) of 88 patients with three vessel, 7 (7 percent) of 101 with two vessel and 0 of 90 with single vessel disease. The decrease in pressure was reproducible in the seven patients who underwent a second exercise test before alteration of therapy; this decrease was abolished in the six patients who exercised again after coronary bypass graft surgery. A decrease in systolic pressure of 10 mm Hg or more also occurred during exercise testing in 3 of 23 patients with noncoronary organic heart disease; all 3 had an obstructive cardlomyopathy that had not been suspected clinically. Only 1 of 158 subjects with chest pain and no demonstrable heart disease had a decrease in systolic blood pressure with exercise. Declines in blood pressure were not observed during 650 maximal exercise tests performed on 560 clinically normal men. In conclusion, if one excludes subjects with cardiomyopathy or significant heart valve disease, a sustained exercise-induced decrease in peak systolic blood pressure of 10 mm Hg or more is a highly specific sign of multiple vessel coronary artery disease. This phenomenon is best explained by acute left ventricular pump failure secondary to extensive myocardial ischemia.