Showing papers by "University of Iowa published in 1977"

The Family History Method Using Diagnostic Criteria: Reliability and Validity

Abstract: • Data concerning familial history of psychiatric disorders are often used to assist in diagnosis, to examine the role of genetic or nongenetic familial factors in etiology, or to develop new methods of classification. Information concerning familial prevalence may be collected by two different methods: the family history method (obtaining information from the patient or a relative concerning all family members), and the family study method (interviewing directly as many relatives as possible concerning their own present or past symptomatology). This study compares these two methods. In general, the family study method is preferred since information is likely to be more accurate. The family history method leads to significant underreporting, but this can be minimized through the use of diagnostic criteria. This study reports on an instrument that has been developed for collecting information concerning family history and that provides criteria for 12 diagnoses—the Family History-Research Diagnostic Criteria. Using diagnostic criteria leads to greater sensitivity, but underreporting remains a major problem of the family history method.

Pollen-ovule ratios: a conservative indicator of breeding systems in flowering plants

Abstract: The evolutionary shift from xenogamy (outcrossing) to autogamy (selfing) has been mediated through decreased flower size and alterations in floral morphology (Ornduff, 1969) which reduce the energetic cost per flower (Cruden, unpubl.) and facilitate self-pollination, respectively. Recently, a number of workers have shown that the flowers of self-incompatible and other xenogamous taxa produce more pollen grains than closely related self-compatible and/or autogamous taxa (Arroyo, 1973; Baker, 1967; Cruden, 1973; Gibbs et al., 1975; Lloyd, 1965; Vries, 1974). In contrast to other floral characteristics the number of ovules per ovary in the taxa studied did not decrease. In these taxa the evolutionary shift from xenogamy to autogamy has been accompanied by a decrease in the ratio of pollen grains to ovules (PIO). It is generally accepted that differences in breeding systems tend to be correlated with successional stages. Colonizers of disturbed habitats and plants of early successional stages tend to be self-compatible and/or autogamous (Baker, 1955, 1959, 1965; Stebbins, 1958) whereas plants of later successional stages, including tropical forest trees, tend to be xenogamous (Baker, 1959; Bawa, 1974; Bawa and Opler, 1975; Stebbins, 1950, 1958). Since, as I will show, PIO's are an integral part of a plant's breeding system, they also should be correlated with habitat or successional stage. My overall objective is to show that PIO's reflect the likelihood of sufficient pollen grains reaching each stigma to result in maximum seed set. The more efficient the transfer of pollen, the lower the PIO should be. It follows logically that cleistogamous flowers should have the lowest PIO's, and that autogamous flowers will have lower PIO's than xenogamous flowers, i.e., that PIO's are correlated with breeding systems. My data show that this is the case and suggest that PI O's are integrated with other facets of a plant's breeding system. Second, I show that there is a strong correlation between the breeding system, hence PIO's, and successional stage. In addition, I briefly circumscribe what constitutes a sufficient number of pollen grains to assure maximum seed set and discuss evidence that supports the notion that some plants tend to minimize pollen production. Finally, I discuss deviations from the general pattern to show that PIO's are a better predictor of a plant's breeding system than other morphological characteristics.

A modified quadratic cost problem and feedback stabilization of a linear system

Abstract: This paper considers a feedback control law for linear systems based on a minimum energy regulator problem with fixed terminal constraints on the state. A modification of this control law based on a receding horizon notion is shown to be asymptotically stable and to result in a new method for stabilizing linear time-varying systems, as well as extending some well-known methods for stabilizing time-invariant systems by state variable feedback.

Origin of Phosphatic Black Shale Facies in Pennsylvanian Cyclothems of Mid-Continent North America

Abstract: Continued lithologic and paleontologic considerations of Kansas Upper Pennsylvanian megacyclothems more firmly establish the basic ascending sequence of: outside (nearshore) shale--middle (transgressive) limestone--core (offshore) shale--upper (regressive) limestone--outside (nearshore) shale, as representing a single transgressive-regressive sequence; this sequence is thus considered simply a cyclothem. Lateral facies change along the 500-km Iowa-Kansas outcrop belt is greatest in upper parts of upper limestones and outside shales, as would be expected in shallow-water to shoreline deposits; it is least in middle limestones, core shales, and bases of upper limestones, as would be expected in deeper water deposits. The widespread phosphatic black shale facies that commonly accompanies maximum transgression in the core shale is explained by water becoming deep enough to develop a thermocline strong enough to prevent bottom oxygenation by wind-driven vertical circulation. Pennsylvanian position of Mid-Continent North America, in the trade-wind belt north of the paleoequator along the Appalachians, allowed establishment of large-scale quasi-estuarine circulation in the Mid-Continent epicontinental sea. Cold, deep, oxygen-poor, phosphate-rich water from the western ocean was drawn in along the bottom through the basins of West Texas eventually to upwell in the eastern Mid-Continent and replace the surface water moved westward out of the sea by the prevailing winds. Upwelling greatly increased surfac -water production of organic matter, which continually settled (while being carried westward) into the deeper incoming current, where it decayed and depleted the remaining oxygen while continually enriching the already high phosphate in a circulatory trap. In this way substantial organic matter and phosphorite were deposited on the anoxic sea bottom to produce the phosphatic black shale facies. This model for offshore phosphatic black shale deposition obviates the difficulty of explaining in shallow tropical water the combination of nonskeletal phosporite production, and widespread lateral uniformity of a quiet anoxic environment between two marine limestones. It supports large-scale Pennsylvanian transgressions and regressions in the Mid-Continent sea, but remains compatible with the local cyclic sedimentary process of delta outbuilding and abandonment along the shoreline. In fact, large-scale marine transgressions and regressions account for the widespread distribution of delta-shoreline deposits from the Appalachians to Kansas. The offshore black shale model can be expanded to a more general depositional model that not only explains the lateral variation in black-shale-be ring Pennsylvanian cyclothems from the Appalachians to West Texas, but also accounts for the scarcity of black shales in younger Pennsylvanian and Permian Mid-Continent cyclothems by suggesting that water depths at maximum transgression during that time were generally too shallow to establish an effective thermocline.

The Treatment of Missing Data in Multivariate Analysis

Abstract: Procedures for treating missing data in the statistical analysis of survey data are reviewed. The main topics covered are: (1) how to assess the nature of missing data especially with regard to randomness, (2) a comparison of listwise and pairwise deletion, and (3) methods for using maximum information to estimate (a) parameters or (b) missing values.

A region of intense plasma wave turbulence on auroral field lines

Abstract: This report presents a detailed study of the plasma wave turbulence observed by HAWKEYE-1 and IMP-6 on high latitude auroral field lines and investigates the relationship of this turbulence to magnetic field and plasma measurements obtained in the same region.

Turbulent diffusion from a quasi-kinematical point of view

Abstract: An estimate for the coefficient of self‐diffusion can be derived whenever the Eulerian velocity spectrum is known. The result is more general than those previously obtained. A comparison is made with computed test‐particle diffusion in an inviscid two‐dimensional Navier–Stokes fluid.

Mathematical analysis of some three-species food-chain models

Abstract: The paper is basically concerned with the question of persistence of all species in a three-level food chain. A general model is introduced and the equilibria analyzed. Boundedness and stability criteria are established. Three special cases of the model are analyzed, showing the applicability of the theory, and in certain cases extensions are given. The special cases include Lotka-Volterra (where we are able to give necessary and sufficient conditions for persistence), Lotka-Volterra predation with a carrying capacity at the lowest level, and a mixed Lotka-Volterra and Holling predation (at different levels) with a carrying capacity at the lowest level.

Structural diversity of gap junctions. A review.

Abstract: Gap junctions are plasma membrane specializations characterized as aggregates of intramembranous particles in two apposed membranes meeting particle-to-particle in the 2–4 nm intermembrane ‘gap’. Recent thin-section and freeze-fracture evidence has revealed significant structural variations of gap junctional structure at various stages of development and from different organisms and tissues. It is suggested that a comparative analysis of these differences may provide clues to the specific biological function(s) of these ubiquitous organelles.

Studies on human memory: the interactions of diazepam, scopolamine, and physostigmine.

Abstract: Seventy volunteers were injected with diazepam (0.3 mg/kg), scopolamine (8 mug/kg), or placebo, followed 70 min later by another injection of physostigmine, physostigmine and methscopolamine (in case of diazepam treatment), or placebo. Physostigmine was given in two doses, 16 and 32 mug/kg; methscopolamine, 8 and 16 mug/kg. Subjects (Ss) were tested in groups of 5 in a double blind procedure with treatments distributed according to a Latin square design. Prior to treatment, Ss heard a series of lists of words, followed by an immediate recall test. Following the first injection, delayed free recall and recognition tests were given. The second drug was then injected, followed by a presentation of another two sets of lists which were tested similarly. Subjective feelings were also evaluated with a rating questionnaire. Diazepam and scopolamine did not affect recall of information which had been learned prior to drug injection. However, both drugs impaired the learning or acquisition of new information. Physostigmine, especially in its high dose, antagonized most of the memory deficits produced by scopolamine while those of diazepam remained. This is a strong indication that scopolamine acts centrally through an anticholinergic mechanism while diazepam may act through a different system.

Optic disc edema in raised intracranial pressure. IV. Axoplasmic transport in experimental papilledema.

Abstract: • Tritiated leucine was Injected intravitreously into the eyes of rhesus monkeys that had developed papilledema secondary to implantation of intracranial balloons Autoradiographic studies of the optic nerve head showed that six hours after intravitreous injection of the isotope the fast component of axoplasmic transport accumulated in the regions of the lamina choroidalis and lamina scleralis The slow component arrived at the optic nerve head two to four days after injection, and the swollen axons of the entire optic nerve head were filled with radioactive isotopes Twelve days after injection of isotope, the axons in the optic nerve head were still diffusely labeled Disturbance of axoplasmic transport was one of the primary events resulting in swelling of axons in papilledema The pattern of axoplasmic disturbances in papilledema secondary to raised intracranial pressure was similar to that observed in papilledema secondary to ocular hypotony or increased intraocular pressure Ocular hypotony, raised intracranial pressure, and increased intraocular pressure appear to share a final common pathway All these conditions apparently converge into this final common pathway of disturbance of axoplasmic transport to give rise to papilledema (Arch Ophthalmol95:1458-1462, 1977)

Synthesis of Proteins and Glycoproteins in Cells Infected with Human Cytomegalovirus

Abstract: In cytomegalovirus-infected cells, the rate of protein synthesis was detected as two peaks. One occurred during the early phase of infection, 0 to 36 h postinfection, and the other occurred during the late phase, after the initiation of viral DNA synthesis. Double-isotopic-label difference analysis demonstrated that host and viral proteins were synthesized simultaneously during both phases. In the early phase, approximately 70 to 90% of the total proteins synthesized were host proteins, whereas approximately 10 to 30% were viral, even at a multiplicity of infection of 20 PFU/cell. Virus-related proteins or glycoproteins were referred to as infected-cell specific (ICS). Two ICS glycoproteins (gp145 and 100) were clearly detectable and were synthesized preferentially in the early phase of infection. Their synthesis was concomitant with stimulation of the protein synthesis rate. In the late phase of infection, approximately 50 to 60% of the total protein synthesis was viral and approximately 40 to 50% was host. The ICS proteins and glycoproteins detected during the late phase of infection were viral structural proteins. Infectious virus was not detectable until 48 to 72 h postinfection. An inhibitor of viral DNA synthesis, phosphonoacetic acid, prevented the appearance of the late-phase ICS proteins and glycoproteins, but there was little or no effect on early ICS glycoprotein synthesis. Radiolabeled ICS proteins and glycoproteins were identified by their relative rates of synthesis, by their different electrophoretic mobilities compared with those of host proteins and host glycoproteins, and by their similar electrophoretic mobilities compared to those of proteins and glycoproteins associated with virions and dense bodies of cytomegalovirus. Structural viral antigens in the infected-cell extracts were removed by immunoprecipitation, using F(ab′)2 fragments of cytomegalovirus-specific antibodies, and identified as described above. The last two criteria were used to identify viral structural ICS proteins and glycoproteins. Although approximately 35 structural proteins were found to be associated with purified virions and dense bodies, the continued synthesis of host cell proteins complicated their identification in infected cells. Nevertheless, seven of the nine structural glycoproteins were identified as ICS glycoproteins.

Oxygen toxicity: comparison of lung biochemical responses in neonatal and adult rats

Abstract: Although immature animals have long been known to be less susceptible to O2, toxicity than adults, the basic mechanism(s) to explain this phenomenon remains unresolved. Two biochemical mechanisms for protection of the lung from O2-induced injury have been proposed: the glutathione (GSH) system in reducing toxic lipid peroxides and the superoxide dismutase (SOD) system in eliminating superoxide anion. Experiments were carried out to determine whether these lung defense systems respond differently in neonatal and adult rats exposed to toxic concentrations of O2. Neonatal rats (4 to 7 days old) and adult rats (250-300 g) wire continuouly exposed to either 96-98% )2 or room air in monitored exposure chambers. All the O2-exposed adult rats showed extensive pulmonary edema and 65% died within 3 days of O2 exposure. Neonatal rats, however, all survived up to 5 days of O2 exposure without gross evidence of lung edema. During the course of exposure animals were sacrificed for biochemical analysis and the data expressed on a per lung basis as % of control values. After 72 hours of O2, exposure neonatal rats showed increased activity of GSH (171%), GSH-peroxidase (GP) (126%), GSH-reductase (GR) (120%). glucose-6-phosphate dehydrogenase (G-6-PD) (139%), and SOD (114%). Adult rats, however, failed to show increases in pulmonary GSH, GP, GR, and SOD activity. Thus, the resistance of the neonatal lung to O2-induced injury may be due to the augmented activity of these protective enzyme systems. (Supported by GM 12675 and NIH 1F32 HL05415.)

Plasma wave electric fields in the solar wind: Initial results from Helios 1

Abstract: Plasma-wave measurements by Helios 1 show that the electric-field intensities in the solar wind are usually very low, much lower than those for comparable measurements near earth, where particles moving upstream from the bow shock often cause large disturbances in the solar wind. The most commonly occurring plasma wave detected by Helios is a sporadic emission at frequencies from about 1 to 10 kHz, between the electron and ion plasma frequencies. These waves are thought to be ion acoustic waves Doppler-shifted upward in frequency from below the ion plasma frequency. The maximum electric-field intensity of these waves is a few hundred microvolts per meter. At higher frequencies, from about 20 to 100 kHz, electron plasma oscillations are detected at frequencies near the local electron plasma frequency. These electron plasma oscillations are more intense, with field strengths sometimes as large as a few millivolts per meter, but occur very infrequently. Both the ion acoustic waves and the electron plasma oscillations show a tendency to occur at higher frequencies closer to the sun but no pronounced variation in intensity with radial distance from the sun. In four cases, electron plasma oscillations have been found in association with type III radio bursts.

Anterior fixed partial dentures utilizing the acid-etch technique and a cast metal framework

Abstract: A technique has been described which permits the fabrication and attachment of an anterior fixed partial denture without tooth preparation. The fixed partial denture is attached to the lingual surfaces of the abutment teeth utilizing a composite resin and acid-etched enamel. Conservation of tooth structure and minimal chair time and patient expense are the primary advantages of this technique.

The Intrinsic-Extrinsic Dichotomy: Toward Conceptual Clarity

Abstract: In this article the authors examine and define the concepts of intrinsic and extrinsic motivation as well as intrinsic and extrinsic outcome. They examine these concepts in the context of employee motivation, noting that intrinsically motivated employees attend to their work due to feelings of self-fulfillment where as extrinsically motivated employees go about their jobs while being driven by factors or events whose delivery is dependent on a source outside of the immediate task. The authors note that the debate will surely continue over this subject and its application in social psychology and urge researchers to continue examining organizational behavior.

Economic status and survival of cancer patients

Abstract: The relation of economic status to survival was studied for 39 kinds of cancer representing all types for which 60 or more indigent patients were seen in University of Iowa Hospital for primary care during the years 1940-1969. For every type the indigent patients had poorer survival than non-indigent patients. Quality of care would be eliminated as a major variable since a second group of "ward" patients of higher economic status was available for comparison and the differences were substantially greater between the two groups of teaching patients than between the "clinic pay" and "private" patients. Age differences and differences in stage of disease accounted for less than half of the survival deficits in the indigents. The two important problems were high mortality from causes other than cancer and excess cancer mortality not accounted for by stage differences, particularly among patients who should have had 5-year survival rates between 40 and 70%. In these patients cancer recurred more often and earlier among the indigent. We postulate host differences associated with poverty that could also account for much of the observed Black-White differences as well as some international differences in cancer survival rates.

Developmental genetics of the Drosophila egg. I. Identification of 59 sex-linked cistrons with maternal effects on embryonic development.

Abstract: Sex-linked mutations to recessive female sterility were induced, sorted for egg-laying, mapped within broad regions and grouped by complementation tests into cistrons. The mutations have also been partially characterized for their temperature sensitivity and pleiotropic effects. Altogether 59 cistrons have been identified, including five allelic with previously known loci: cin, fs(1)N, mk, sn, and r. All of the genes make maternal contributions to developing embryos. In some instances mutant defects are recognized in the egg envelopes; in the remainder the defects are presumably in the egg cytoplasm. For mutations in twenty-two genes, including cin, mk, and r alleles, the lethality of the maternal effect is reversed and the embryo is "rescued" by the action of a wild-type, paternal allele. The mutant strains are potentially important for the study of developing egg envelopes and for furthering the analysis of causation in embryogenesis and its origins in oogenesis.

A plasma wave investigation for the Voyager Mission

Abstract: The Voyager Plasma Wave System (PWS) will provide the first direct information on wave-particle interactions and their effects at the outer planets. The data will give answers to fundamental questions on the dynamics of the Jupiter and Saturn magnetospheres and the properties of the distant interplanetary medium. Basic planetary dynamical processes are known to be associated with wave-particle interactions (for instance, solar wind particle heating at the bow shock, diffusion effects that allow magnetosheath plasma to populate the magnetospheres, various energization phenomena that convert thermal plasma of solar wind origin into trapped radiation, and precipitation mechanisms that limit the trapped particle populations). At Jupiter, plasma wave measurements will also lead to understanding of the key processes known to be involved in the decameter bursts such as the cooperative mechanisms that yield the intense radiation, the observed millisecond fine-structure, and the Io modulation effect. Similar phenomena should be associated with other planetary satellites or with Saturn's rings. Local diagnostic information (such as plasma densities) will be obtained from wave observations, and the PWS may detect lightning whistler evidence of atmospheric electrical discharges. The Voyager Plasma Wave System shares the 10-meter PRA antenna elements, and the signals are processed with a 16-channel spectrum analyzer, covering the range 10 Hz to 56 kHz. At selected times during the planetary encounters, the PWS broadband channel will operate with the Voyager video telemetry link to give complete electric field waveforms over the frequency range 50 Hz to 10 kHz.