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Showing papers by "University of Iowa published in 1976"


Journal ArticleDOI
TL;DR: In this article, the authors present evidence on the existence of seasonality in monthly rates of return on the New York Stock Exchange from 1904-1974, and explore possible implications of the observed seasonality for the capital asset pricing model and other research.

1,243 citations


Journal ArticleDOI
TL;DR: In this article, a fast and accurate method of solving the Vlasov equation numerically in configuration space is described. But the method is very accurate and efficient, and it does not handle nonperiodic spatial boundary conditions.

802 citations


Journal ArticleDOI
TL;DR: Deterministic communicable disease models which are initial value problems for a system of ordinary differential equations are considered, where births and deaths occur at equal rates with all newborns being susceptible.
Abstract: Deterministic communicable disease models which are initial value problems for a system of ordinary differential equations are considered, where births and deaths occur at equal rates with all newborns being susceptible. Asymptotic stability regions are determined for the equilibrium points for models involving temporary immunity, disease-related fatalities, carriers, migration, dissimilar interacting groups, and transmission by vectors. Epidemiological interpretations of all results are given.

682 citations


Journal ArticleDOI
TL;DR: The observation of elevated FSH concentrations and normal LH levels in perimenopausal women emphasizes the complexity of the hypothalamic-pituitary-ovarian regulatory system and suggests that LH and FSH are modulated independently at the level of the pituitary.
Abstract: Studies of menstrual cycle length in large populations demonstrated that there is a striking increase in the variability of intermenstrual intervals just before menopause. The changes in serum concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E2), and progesterone (P) during menstrual cycles in a group of perimenopausal women were compared with the findings in young normal women. In 8 women, 46-56 years old with regular cycles, cycle length was shorter and the mean E2 concentration was lower than in younger women. There was a striking increase in FSH concentration throughout the cycle while LH remained in the normal range. In 2 women, 14 cycles of variable length were studied during 2 years of the menopausal transition. In some instances, hormonal changes associated with follicular maturation and corpus luteum function occurred in the presence of high, menopausal levels of LH and FSH with a diminished secretion of E2 and P. In others vaginal bleeding occurred during a fall in serum E2 with no associated rise in P. Cycles of variable length during the menopausal transition may be due either to irregular maturation of residual follicles with diminished responsiveness to gonadotropin stimulation, or to anovulatory vaginal bleeding that may follow estrogen withdrawal without evidence of corpus luteum function. The observation of elevated FSH concentrations and normal LH levels in perimenopausal women emphasizes the complexity of the hypothalamic-pituitary-ovarian regulatory system and suggests that LH and FSH are modulated independently at the level of the pituitary.

579 citations


Journal ArticleDOI
TL;DR: The results of an extensive study of plasma waves in the distant magnetotail on the basis of measurements from the Imp 8 spacecraft are discussed in this article, where three distinctly different types of plasma wave turbulence are detected.
Abstract: The results of an extensive study of plasma waves in the distant magnetotail on the basis of measurements from the Imp 8 spacecraft are discussed. The plasma measurements are compared with plasma and magnetic field measurements described by Frank et al. (1976) to study the relationship of the plasma waves to the various plasma regimes found in the distant magnetotail. Three distinctly different types of plasma wave turbulence in the distant magnetotail are detected. The first, most frequently occurring type of turbulence, consists of broadband electrostatic noise at frequencies between 10 Hz and a few kHz. The second, less frequent type of plasma wave turbulence consists of intense (100 milligamma) bursts of low frequency (10 to 300 Hz) magnetic noise. The third, least frequent type of turbulence consists of electrostatic waves near harmonics of the electron gyrofrequency.

356 citations


Journal ArticleDOI
TL;DR: A pharmacokinetic analysis indicated that the higher rate of APAP‐suljate formation in younger age groups apparently compensated for a deficiency in glucuronide formation, despite the quantitative changes in the metabolic pathways during early childhood.
Abstract: The elimination of acetaminophen (APAP) following an oral dose of 10 mg/kg in newborn infants, children, and adults was compared. Urinary excretion of unchanged APAP, APAP-sulfate, and APAP-glucuronide was complete within 30 hr at all ages. Higher percentages of the dose were excreted in the urine as APAP-sulfate in neonates (0-2 days old) and children (3-9 yr old) than in 12-yr old children and adults. A pharmacokinetic analysis indicated that the higher rate of APAP-sulfate formation in younger age groups apparently compensated for a deficiency in glucuronide formation. No dramatic age-related differences in the overall elimination rate constant for APAP were observed despite the quantitative changes in the metabolic pathways during early childhood.

283 citations


Journal ArticleDOI
TL;DR: In this paper, the articulatory transition velocities were studied within and between speakers, and a direct relationship was observed between articulatory velocity and displacement both within and across speakers.

226 citations


Journal ArticleDOI
TL;DR: There are many different definitions of what constitutes culture-fair selection, and each implicitly, though unfortunately not explicitly, involves a particular set of value judgments with different implications for how selection should be accomplished as mentioned in this paper.
Abstract: in this process. There are many different definitions of what constitutes culture-fair selection, and each implicitly, though unfortunately not explicitly, involves a particular set of value judgments with different implications for how selection should be accomplished. For each of these definitions a remedy has been proposed. Our purpose in this paper is to show that some of these approaches are inadequate to their task and that more complex analyses are required. DESCRIPTION OF THE SELECTION PROCESS The selection process can be characterized in the same manner for all selection models. First, there are individuals about whom decisions are required. These decisions are to be based on information about the individuals. The information is processed by some strategy which leads to a final decision. The final decision ends the decision-making process by assigning the individual to either a selected or an outselected group. The outcome is the individual's performance after the assignment or, in other words, the consequences resulting from the decision (Cronbach & Gleser, 1965, p. 18). A strategy is a rule for making decisions. Each selection model represents a strategy, the intent of which is to guarantee cultural fairness in the selection process. Information is generally provided by a test, and we shall use the term test to refer to all information-gathering procedures including interviews and physical measurements. The overriding problem is the lack of agreement as to the meaning of the term culture-fair selection. Each of the selection models or strategies we discuss can be characterized in the same manner. It is assumed that the applicants to an educational institution, to a training program, or for employment can be separated into subpopulations because of an a priori belief that the assumed linear regressions within these subpopulations are different-that is, the test (or predictor) may be more valid for some subpopulations than for others (different slopes), and/or for a fixed value of the predictor, the level of criterion performances may differ (different intercepts), or that some differential selection criterion is appropriate for various subpopulations. Alternatively, these subpopulations may be differentiable primarily because of public concern with what is going on in them and a public need to verify that all subpopula

217 citations



Journal ArticleDOI
TL;DR: The mechanical properties of the human lumbar annulus fibrosus is investigated both theoretically and experimentally and Spencer's theoretical approach is followed, but the fibers of the material are considered to be extensible.

197 citations


Journal ArticleDOI
TL;DR: In this article, homeowners were interviewed and expected to be either personally identified (public commitment) or not identified (private commitment) as having agreed to attempt energy conservation, and the response measure of energy usage was provided by utility-meter readings for the month following the interview.
Abstract: Homeowners were interviewed and expected to be either personally identified (public commitment) or not identified (private commitment) as having agreed to attempt energy conservation. The response measure of energy usage was provided by utility-meter readings for the month following the interview. Homeowners under public commitment showed a lower rate of increase in the use levels for both natural gas (Experiment I) and electricity (Experiment II) than under private commitment or in the control (no interview condition). Results from a set of self-monitoring conditions suggested that conservation may be related to increased attention to energy use levels.

Journal ArticleDOI
TL;DR: In this paper, the magnetic-field-dependent resonances of spin-aligned hydrogen and deuterium have been studied and shown to be stable in the presence of field-induced predissociations.
Abstract: Spin-aligned hydrogen (H \ensuremath{\uparrow}) and deuterium (D \ensuremath{\uparrow}) are generally predicted to be stable for $\frac{\mathcal{H}}{T}\ensuremath{\gtrsim}{10}^{6}$ G/K. Magnetic-field-dependent resonances (inverse to field-induced predissociations of high vibrational-rotational levels of HD and ${\mathrm{D}}_{2}$) provide exceptions to this general rule. Their existence suggests 50 kG (H \ensuremath{\uparrow} + D \ensuremath{\uparrow}) and 19 kG (D \ensuremath{\uparrow} + D \ensuremath{\uparrow}) should be avoided for stable H \ensuremath{\uparrow} and D \ensuremath{\uparrow}. Induced predissociation observations should yield ultraprecise resonance information and dissociation limits.

Journal ArticleDOI
TL;DR: It was concluded that a strong stereotype of a stutterer's personal characteristics exists, that the stereotype is predominantly unfavorable, thatThe stereotype is essentially unaffected by amount of exposure to actual stutterers, and that the traits attributed to boys and men who stutter are similar.
Abstract: To determine if a stereotype of the “typical stutterer” exists and to identify possible differences in that stereotype due to exposure to stuttering, seven groups of subjects having a wide range of...

Journal ArticleDOI
01 May 1976-Chest
TL;DR: In a prospective study, 11 patients out of 742 patients had angiographically proven coronary artery aneurysms, and these 11 cases plus the 23 previously reported ante mortem form the total reported in world literature.

Journal ArticleDOI
TL;DR: It is argued that the time interval between synthesis in the cytoplasm and deposition onto DNA can be easily detected and accounts for previous observations of 32P incorporation during G1 and S phase and in the presence of inhibitors of DNA and histone synthesis.

Journal ArticleDOI
TL;DR: In this article, it is suggested that these waves are interacting with energetic protons, alpha particles, and other heavy ions trapped near the magnetic equator, and the possible role these waves play in controlling the distribution of the energetic ions is considered.
Abstract: An intense band of electromagnetic noise is frequently observed near the magnetic equatorial plane at radial distance from about 2 to 5 Re. Recent wideband wave-form measurements with the IMP-6 and Hawkeye-1 satellites have shown that the equatorial noise consists of a complex superposition of many harmonically spaced lines. Several distinctly different frequency spacings are often evident in the same spectrum. The frequency spacing typically ranges from a few Hz to a few tens of Hz. It is suggested that these waves are interacting with energetic protons, alpha particles, and other heavy ions trapped near the magnetic equator. The possible role these waves play in controlling the distribution of the energetic ions is considered.

Journal ArticleDOI
TL;DR: In this article, the authors examined the intergenerational transmission of marital instability with the use of data from five surveys, four of them from national samples, and found that respondents from parental homes that were disrupted by death or divorce during their childhood had higher rates of divorce or separation in their own first marriages.
Abstract: The intergenerational transmission of marital instability was examined with the use of data from five surveys, four of them from national samples. Among blacks, whites, males, and females, respondents from parental homes that were disrupted by death or divorce during their childhood had higher rates of divorce or separation in their own first marriages. Except for black males, a greater transmission effect was found among respondents from childhood homes disrupted by divorce or separation rather than by death. Implications from the literature on sex-role learning in children were examined by comparing the transmission effect for respondents who, after having their parental homes disrupted, were reared in households of different composition. The results indicated that the role model rationale for the transmission of marital instability must be elaborated before it can successfully account for the findings from existing national surveys.

Journal ArticleDOI
TL;DR: The premature infant may be compromised when exposed to the relative hyperoxia of the extrauterine environment by a reduced complement of the enzyme or a reduced ability to increase pulmonary SOD activity in response tohyperoxia.
Abstract: Pulmonary superoxide dismutase (SOD) acitivity was determined for various groups of human fetuses, infants, and adults. Enzyme activity was found to increase with age from a low of 17 +/- 1 units/mg DNA in fetal lung to 49 +/- 6 units/mg DNA in infant lung and finally to 110.2 +/- 14.8 units/mg DNA in adult lung (P less than 0.05). No difference in lung SOD activity was demonstrated between normal infants and those with idiopathic respiratory distress/hyaline membrane disease (IRDS/HMD). No significant differences in SOD activity were found among all the samples of infant blood. Adult blood samples, however, contained significantly greater SOD activity both in terms of heme concentration and volume of whole blood (P less than 0.05). SOD activity in lung tissue from both rats and rabbits were also found to increase with age from a low value in fetal animals to a maximum activity in adults (P less than 0.05). Exposure of New Zealand White rabbits, prematurely delivered by caesarian section, to 80% oxygen for 24 hr resulted in a 42% increase in lung SOD activity. Similarly, 7-day-old Sprague-Dawley rats exposed to 85% oxygen for 24 hr showed a 43% increase in pulmonary SOD activity. No increase in pulmonary SOD was observed when adult rats were exposed to 85% oxygen for 24 hr. The effect of hyperoxia on SOD activity in excised lung was investigated. Rat lung, incubated in either heparinized whole blood or in plasma and exposed to 100% oxygen, showed a 30% increase in SOD activity after 2 hr. This capacity of lung tissue to respond to hyperoxia in vitro with increased SOD activity was age dependent. The maximum increase in SOD activity was seen with lungs from 10-12-day-old rats. The oxygen-stimulated increase in lung SOD activity disappeared at about 19-20 days of age.

Journal ArticleDOI
10 Dec 1976-Science
TL;DR: Observations confirm the basic mechanism, proposed in 1958, that type III radio emissions are produced by intense electron plasma oscillations excited in the solor corona by electrons ejected from a solar flare.
Abstract: Plasma wave electric field measurements with the solar orbiting Helios spacecraft have shown that intense (approximately 10 millivolts per meter) electron plasma oscillations occur in association with type III solar radio bursts. These observations confirm the basic mechanism, proposed in 1958, that type III radio emissions are produced by intense electron plasma oscillations excited in the solor corona by electrons ejected from a solar flare.

Journal ArticleDOI
01 Nov 1976-Chest
TL;DR: A new "wedge" method of transbronchial forceps biopsy is now being utilized in the bronchoscopic unit, and the tip of the flexible fiberoptic bronchoscope is lodged into the appropriate segmental bronchus to tamponade any bleeding and prevent blood from flooding the airway.

Journal ArticleDOI
TL;DR: This article reviewed consumer behavior and found that attitude change, information seeking, and brand loyalty are correlated with the concept of cognitive dissonance in consumer behavior, and they also found that consumer behavior can be categorized into three types of behaviors: positive, negative, and negative.
Abstract: Researchers in consumer behavior have attempted to relate attitude change, information seeking, and brand loyalty to the concept of cognitive dissonance. The writers review the consumer behavior li...

Journal ArticleDOI
TL;DR: Two common interactional patterns through which the marijuana user establishes the relationships of trust necessary for his drug-related activity are examined and it is suggested that these two interactional pattern may occur among groups as well as between individuals.
Abstract: Trust has been little investigated outside the experimental laboratory situation, and its processual aspects have largely been neglected (cf. Swinth, 1967). Two common interactional patterns through which the marijuana user establishes the relationships of trust necessary for his drug-related activity are examined. The “disclosure pattern” occurs in three stages and provides the marijuana user with a coherent set of “identity documents” (Gross and Stone, 1964) as a basis for defining another person as trustworthy. The “extension pattern” provides the marijuana user with a trusted third party's definition of another as trustworthy as a basis for defining that other as trustworthy. It is suggested that these two interactional patterns may occur among groups as well as between individuals.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the canonical distribution of compressive turbulent flows in the framework of ideal magnetohydrodynamics and found three constants of the motion which survive the truncation in Fourier space and permit the construction of canonical distributions with three independent temperatures.
Abstract: Incompressible turbulent flows were investigated in the framework of ideal magnetohydrodynamics. Equilibrium canonical distributions are determined in a phase whose coordinates are the real and imaginary parts of the Fourier coefficients for the field variables. The magnetic field and fluid velocity have variable x and y components, and all field quantities are independent of z. Three constants of the motion are found which survive the truncation in Fourier space and permit the construction of canonical distributions with three independent temperatures. Spectral densities are calculated. One of the more novel physical effects is the appearance of macroscopic structures involving long wavelength, self-generated, magnetic fields ("magnetic islands"). In the presence of finite dissipation, energy cascades to higher wave numbers can be accompanied by vector potential cascades to lower wave numbers, in much the same way that in the fluid dynamic case, energy cascades to lower wave numbers accompany entropy cascades to higher wave numbers.

Journal ArticleDOI
TL;DR: The neural discharge from autonomic CNS neurons on the circulation is defined by three factors: the continuous influx of afferent neural impulses that originate in the cardiovascular system as well as in other tissues and other parts of the CNS.

Journal ArticleDOI
TL;DR: In this paper, a description of the Depersonalization in the face of Life-Threatening Danger: A Description is given, along with a discussion of the effects of self-deletion.
Abstract: (1976). Depersonalization in the Face of Life-Threatening Danger: A Description. Psychiatry: Vol. 39, No. 1, pp. 19-27.

Journal ArticleDOI
TL;DR: Comparison of species of bacteria isolated from patients with endometritis with species isolated from normal pregnant and nonpregnant women suggests that bacteria causing infections are indigenous to the genital tract, however, complete studies of the flora of pregnant women, especially anaerobic flora, are lacking.

Journal ArticleDOI
TL;DR: In order to contribute to the development of an international perspective on crime and to examine a central tenet similar to many theoretical perspectives on the etiology of crime, cross-national d... as discussed by the authors.
Abstract: In order to contribute to the development of an international perspective on crime and to examine a central tenet similar to many theoretical perspectives on the etiology of crime, cross-national d...


Journal ArticleDOI
TL;DR: The experiment showed that the pressor response to intraventricular angiotensin II is due to both sympathetic and pituitary hormonal components and both are dependent on sites sensitive to ang Elliotensin in the anterior third ventricule.

Journal ArticleDOI
TL;DR: The reliability of myocardial perfusion scintigrams with thallium-201 (201TI) for detecting areas of hypoperfusion was assessed in 16 closed-chest dogs and the results indicate that abnormal scints could be detected in the presence of lesser deficits than in the dogs.
Abstract: The reliability of myocardial perfusion scintigrams with thallium-201 (201Tl) for detecting areas of hypoperfusion was assessed in 16 closed-chest dogs. Variable areas of ischemia were produced either by occluding or stenosing the left anterior descending coronary artery. Cardiac scintigrams taken in four projections were compared with regional myocardial perfusion maps. Segmental concentrations and segmental perfusions were quantitated by counting the emissions from 201Tl and the microspheres in each of 96 segments of the left ventricle. In addition, studies with a phantom were performed. The results indicate: 1) The emissions from 201Tl and from microspheres correlated well in ischemic segments (r = 0.93 +/- SE 0.02). 2) Seven of twelve ischemic hearts had definitely abnormal scintigrams and in each of these the hypoperfused zone was greater than 4.9 grams and perfusion was decreased by more than 45%. 3) In the phantom, abnormal scintigrams could be detected in the presence of lesser deficits than in the dogs. The limitation of the thallium perfusion scintigrams will be the inconsistent detection of small perfusion deficits.