Showing papers by "University of Iowa published in 1974"

The Earth as a radio source: Terrestrial kilometric radiation

Abstract: Based on Imp 6 and 8 satellite observation data, a comprehensive study of terrestrial kilometric radiation is presented. In the light of these data, the earth appears to be a very intense planetary radio source, with a total power output comparable to the decametric radio emission from Jupiter. Terrestrial kilometric (i.e., about 50-500 kHz) radiation seems to originate from low altitudes in the auroral region.

Factors Effecting Late Results After Meniscectomy

Abstract: Meniscectomy has frequently been performed on the assumption that the absence of a meniscus has little effect on joint function. Statistical analysis of data obtained from the histories, physical examinations, and roentgenographic and electrogoniometric studies of ninety-nine patients with a mean follow-up of 17.5 years after meniscectomy revealed a high incidence of poor results, degenerative arthritis, ligamentous laxity, and decreased stance-phase flexion. A meniscus should be removed only when it is definitely abnormal.

Adaptive Robust Procedures: A Partial Review and Some Suggestions for Future Applications and Theory

Abstract: After providing some background for the need to consider estimates other than those resulting from normal theory, there is a brief review of some nonadaptive robust estimators. We introduce adaptive estimators using those of Tukey and McLaughlin, Jaeckel, Johns, Birnbaum and Mike, Takeuchi, Hajek, van Eeden, and Beran. Adaptive estimators based on preliminary testing and Stein-like procedures are then considered, and recommendations are made on how to select the amount of trimming. Various proposals for estimating regression coefficients are also considered. Adaptive distrubution-free tests look very promising for improving the power of nonparametric tests, and some of these techniques can be used effectively in data analysis. Asymmetric trimmed means, adapted to the particular sample, can easily be used with data and provide good descriptive statistics having an approximate error structure. Finally, it is conjectured that estimators based on “cliff-hangers” might be extremely effective if there ...

Detection of heat-labile Escherichia coli enterotoxin with the use of adrenal cells in tissue culture.

Abstract: Cell-free culture filtrates of heat-labile enterotoxin-producing strains of Escherichia coli are capable of inducing morphological changes and steroidogenesis in monolayer cultures of adrenal cells. These tissue culture changes are simiar to those induced by cholera enterotoxin and cannot be effected by culture filtrates of other enterotoxigenic or enteropathogenic types of bacteria. The results of the tissue culture studies correlated well with those done in the standard intestinal-loop systems and suggest that this tissue culture system could be used to significantly aid epidemiological and molecular studies with heat-labile Escherichia coli enterotoxin.

A Generalized EOQ Model for Items with Weibull Distribution Deterioration

Abstract: A generalized form of Covert and Philip's EOQ model with Weibull distribution deterioration is developed. Specifically, the 3-parameter Weibull distribution is used to represent the time to deterioration. It is shown that this model can be related to the previously developed simpler models. The solutions to two numerical examples are compared to Covert and Philip's solution.

An adoption study of antisocial personality.

Abstract: To test the hypothesis that heredity contributes to the development of antisocial personality a group of offspring born to female offenders and given up for adoption in infancy was examined. Forty-six probands and an equal number of control adoptees over 18 years old were followed up and interviewed. A significantly higher rate of antisocial personality was found among the probands than among the controls. The nonantisocial probands proved not to be more deviant than the controls. The antisocial probands experienced certain unfavorable conditions in infancy that may be related to the development of antisocial personality, the most notable being the length of time spent in temporary care prior to final placement. Although the control group was equally exposed to the same conditions, they did not develop a high rate of the disorder. The findings point to the importance of interactions between genetic and environmental factors in the development of antisocial personality.

Statistical mechanics of negative temperature states

Abstract: The dynamics of two-dimensional interacting line vortices is identical to that of the two-dimensional electrostatic guiding center plasma. Both are Hamiltonian systems and are therefore susceptible to statistical mechanical treatments. The predictions of the microcanonical ensemble are explored for this system. Interest focuses primarily on the regime of total positive interaction energy, which should be above the Onsager negative temperature threshold. Calculations of the probability distribution for a component by means of the central limit theorem are carried out in the manner of Khinchin. The probability distribution of a component reduced to the usual Gibbs distribution in the regime of positive temperatures, and is still explicitly calculable for negative temperatures. The negative temperature states are neither quiescent nor spatially uniform. Expressions for the temperature are explicitly provided in terms of the total particle energy and particle number. A BBGKY hierarchy can be derived for both temperature regimes. Numerical simulations involving solutions of the equations of motion of 4008 particles are presented.

Structure of inositol hexaphosphate--human deoxyhaemoglobin complex.

Abstract: D-2,3-DIPHOSPHOGLYCERATE (DPG) facilitates the transfer of oxygen from human red blood cells to the tissues by lowering the oxygen affinity of haemoglobin1. It does so by combining preferentially with one of the two alternative forms of haemoglobin, namely the deoxy form, in the ratio of 1 mol per mol tetramer. Its binding site was predicted from biochemical and model building experiments and then determined directly by X-ray crystallography2. The site lies at the entrance to the central cavity between the N-termini of the β chains and is surrounded by four pairs of basic groups: the α amino group of valine 1 and the side chains of histidines 2 and 143, and of lysine 82. The basic groups are related in pairs by the molecular dyad and arranged so as to complement the acidic groups of DPG by forming seven salt bridges (Fig. 1). On oxygenation the N-termini of the β chains move apart and the cavity closes up so that the stereochemical complementarity is lost3. Oxyhaemoglobin does also bind DPG, but much more weakly, and the binding site is still unknown.

A Threshold Model

Abstract: In the model discussed in the previous section, the function T(t) was prescribed a priori. Except for the case of constant delay, it is by no means clear how one would expect to know this function. In this section we add a phenomenon to the model, a threshold effect, which yields the delay as a function of I(t). In order to allow for variations in the infection rate, we now allow r, of the previous models, to be a function r(t). For example, it might be periodic to account for seasonal variations.

Pavlovian appetitive contingencies and approach versus withdrawal to conditioned stimuli in pigeons.

Abstract: Three experiments investigated the directed skeletal movements of pigeons toward signals of food or no food. Pigeons approached and pecked an illuminated key that was positively correlated with food delivery and positioned themselves relatively far from an illuminated key that was negatively correlated with food delivery. Key illuminations alone, random presentations of key illuminations and food, and backward pairings of key illuminations and food did not produce keypecking or consistent approach/ withdrawal. Therefore, directed skeletal behavior—often believed to be conditioned and maintained primarily or exclusively by \"operant\" procedures—also emerges on \"Pavlovian\" procedures. Several kinds of alternative explanations (e.g., conditioned reinforcement effects, stimulus substitution) for these phenomena were considered, and some potential implications for operant discrimination learning were briefly explored.

Morphine metabolism in man.

Abstract: Morphine metabolism was studied in 6 normal men at weekly intervals after intravenous, intramuscular, subcutaneous, and oral administration. Morphine was rapidly absorbed after intramuscular and subcutaneous iniection, producing plasma levels of free morphine, from 15 minutes to 3 hours, which are significantly higher than levels after intravenous administration. Intravenous morphine, while initially higher, undergoes more rapid distribution, metabolism, and excretion. Morphine is well absorbed from the gastrointestinal tract, but is so rapidly coniugated with glucuronide in the cells of the intestinal mucosa and liver that significant levels of free morphine are not found in either the plasma or urine, whereas the levels of coniugated morphine are high. N-demethylation of morphine is greater after oral than after parenteral administration. While route of administration alters plasma levels of free morphine, it does not alter plasma half-life.

Anorexia nervosa: demographic and clinical features in 94 cases.

Abstract: &NA; A comprehensive chart study was made of numerous clinical and demographic features in 94 patients with anorexia nervosa. Unlike other large series, this survey included the pediatric age group. A significantly greater maternal and paternal age at time of the patient's birth and a greater incidence of both low and high birth weights compared with the general population was found. A relatively high occurrence of premorbid feeding problems was present. Anxiety and obsessive‐compulsive traits were frequent premorbid symptoms. Precipitating events were identified more frequently in patients with a greater age at onset of illness. Characteristic behavior noted during the course of this illness is described.

Criteria for Subtyping Schizophrenia: Clinical Differentiation of Hebephrenic and Paranoid Schizophrenia

Abstract: A total of 260 process schizophrenics were studied to determine the presence of clinical differences supporting the classification of hebephrenic and paranoid subgroups. Hebephrenics, it would appear, have an earlier age of onset, inappropriate or flat affect, and formal thought disorder; paranoids are primarily distinguished by a later age of onset, the presence of well-organized delusions or hallucinations, and the absence of affective changes. In comparison, paranoids tended toward a more favorable outcome, and less familial schizophrenia. Diagnosis of subtypes by computer, based on clinical differences within the process group, yielded a high rate of concordance with clinician subtyping. Based on these findings and currently available literature, a comparative summary of the clinical differences between these subtypes is presented, and criteria for selecting homogeneous subtypes for further research are proposed.

The problem of germ cell determinants.

Abstract: Publisher Summary This chapter discusses the problem of germ cell determinants, it emphasized that the underlying mechanism involved in the origin, deposition, and mode of expression of all localized tissue-determining substances in the oocyte may be similar. The differentiation and organization within the oocyte, whether it involves so-called germ cell determinants, yolk deposition, polarity, or symmetry, depend basically on the nature of the information stored in the genes, and upon a suitable cytoplasmic environment in which they may normally and sequentially express themselves during the development and life cycle of the organism. The experimental studies of chromatin diminution are given. Molecular aspects of chromatin elimination in Ascaris lumbricoides have recently been investigated specifically with respect to a comparison of the informational content of Ascaris cells before and after chromatin elimination. These studies indicate that chromatin elimination in Ascaris leads to a quantitative difference in information content of the somatic cell line versus the germ cell line.

Fixed point theorems for non-Lipschitzian mappings of asymptotically nonexpansive type

Abstract: LetX be a Banach space,K a nonempty, bounded, closed and convex subset ofX, and supposeT:K→K satisfies: for eachx∈K, lim sup i→∞{sup y∈K ‖t ix−Tiy∼−‖x−y‖}≦0. IfT N is continuous for some positive integerN, and if either (a)X is uniformly convex, or (b)K is compact, thenT has a fixed point inK. The former generalizes a theorem of Goebel and Kirk for asymptotically nonexpansive mappings. These are mappingsT:K→K satisfying, fori sufficiently large, ‖Tix−Tiy‖≦k i‖x−y∼,x,y∈K, wherek i→1 asi→∞. The precise assumption in (a) is somewhat weaker than uniform convexity, requiring only that Goebel’s characteristic of convexity, ɛ0 (X), be less than one.

Herbert Hoover, the Commerce Secretariat, and the Vision of an “Associative State,” 1921–1928

Abstract: IN recent years, the traditional image of American governmental activity in the 1920s has been substantially altered. Delving beneath the older stereotypes of "normalcy" and "retrenchment," scholars have found unsuspected survivals of progressivism, a growing federal bureaucracy that tried to use as well as serve business groups, and an incipient form of "indicative planning" based on corporatist rather than classical economics. In many respects, they have concluded, the period should be viewed as the beginnings of the "modern era," not as a reversion to past patterns or as a frivolous and wasted interlude between progressivism and the New Deal.' And for some, the 1920s has more current relevance than the decades that followed, particularly in efforts to balance technological needs with America's individualistic heritage, build an international community without policing the world, and work out bureaucratic arrangements that would nourish individual, community, and private effort rather than supplant them.2

Effects of interplanetary shock waves on energetic charged particles

Abstract: Experimental data on the influence of interplanetary perpendicular and oblique shock waves on the ambient energetic protons are presented along with a theoretical analysis of the acceleration of particles in almost perpendicular shock waves. It was found that low-energy protons can be accelerated in perpendicular shock waves by repeated crossings of the shock front up to a maximum energy given by the product of their initial energy times the ratio of the magnetic fields. High-energy protons need to stay at the shock front for longer times than low-energy protons in order to reach the same relative energy gain. In the theoretical study of proton acceleration at almost perpendicular shock waves, it was found that protons reflected at shock waves with the angle between the upstream magnetic field and the shock normal greater than about 80 deg achieve large energy gains at the shock front. The larger this angle, the higher the energy gain. However, the reflection and energization of protons at these shock waves is not 'instantaneous', neither is it a one-step process: it is performed through repeated crossings of the shock front.

Measurement of plasma LH, FSH, estradiol and progesterone in disorders of the human menstrual cycle: the short luteal phase.

Abstract: Blood levels of LH, FSH, estradiol (E2) and progesterone (P) were determined daily during 11 cycles in 4 women with a luteal phase of less than 10 days. In all cycles peak preovulatory estradiol levels were subnormal. Luteal phase secretion of both estradiol and progesterone was more than 2 sem below normal and mean, midfollicular phase FSH was lower than found in a group of normal cycles. In 2 individuals the defect was found to occur repetitively in cycles analyzed for up to 1 yr. All cycles were of normal total duration. The menstrual cycle with a short luteal phase may be a distinct and common form of infertility. When identified, it may be amenable to specific treatment with human chorionic gonadotropin or gonadotropin-releasing hormone.

Direction finding measurements of auroral kilometric radiation

Abstract: Direction finding measurements with plasma wave experiments onboard the Hawkeye-1 and IMP-8 satellites were used to locate the source region of auroral kilometric radiation. The radiation exhibits peak intensities between about 100 kHz and 300 kHz, and emits intense sporadic bursts lasting for between one half hour to several hours. The total power emitted in this frequency range exceeds 10 to the 9th power watts at peak intensity. The occurrence of the radiation is known to be closely associated with bright auroral arcs which occur in the local evening auroral regions.

The magnetosphere of Jupiter as observed with Pioneer 10: 1. Instrument and principal findings

Abstract: Description of the first in situ observations of energetic electrons of energy greater than 0.06 MeV in the magnetosphere of Jupiter during November-December 1973. The outer magnetosphere has the form of a thin disklike quasi-trapping region extending from about 20 to over 100 Jovian radii. This magnetodisk is confined near the magnetic equatorial plane and has approximate axial symmetry about the magnetic axis of the planet. The observations inside a radial distance of 12 Jovian radii are well organized by a centered dipolar model of the planet's magnetic field with a tilt of 9.5 plus or minus 0.5 deg to the rotational axis and with pole at a system III longitude of 230 plus or minus 3 deg. Absolute omnidirectional intensities of electrons within the stable trapping region inside 20 Jovian radii are given for five energy ranges greater than 0.06, 0.55, 5.0, 21, and 31 MeV.

Active and placebo treatment effects on moderate insomnia under counterdemand and positive demand instructions.

Abstract: Forty-eight sleep-disturbed college students were assigned to one of four conditions: relaxation training, single-item desensitization, placebo, and no treatment. Counterdemand instructions were given during the first three sessions: subjects were told that improvement in sleep disturbance would not occur until after the fourth session. Relaxation and desensitization procedures produced significantly greater reports of improvement in latency of sleep onset than placebo and no treatment during the counterdemand period, while all three treated groups reported significantly greater improvement than no treatment after the fourth (positive demand) session. The results supported the effectiveness of relaxation therapy in the treatment of moderate insomnia. Demand characteristics may contribute to subject reports, but the use of counterdemand instructions allows for valid comparisons among therapy conditions.