Showing papers by "University of Iowa published in 1985"

Severe disturbance of higher cognition after bilateral frontal lobe ablation Patient EVR

Abstract: After bilateral ablation of orbital and lower mesial frontal cortices, a patient had profound changes of behavior that have remained stable for 8 years. Although he could not meet personal and professional responsibilities, his “measurable” intelligence was superior, and he was therefore considered a “malingerer.” Neurologic and neuropsychological examinations were otherwise intact. CT, MRI, and SPET revealed a localized lesion of the orbital and lower mesial frontal cortices. All other cerebral areas had normal structure and radioactivity patterns. Such impairments of motivation and complex social behavior were not seen in control cases with superior mesial or dorsolateral frontal lesions.

Devonian eustatic fluctuations in Euramerica

Abstract: The Devonian System of Euramerica contains at least 14 transgressive-regressive (T-R) cycles of eustatic origin. These are separated into three groups (or depophases) and from Carboniferous cycles by three prominent regressions. Twelve post-Lochkovian T-R cycles are recognized, and they commonly appear to result from abrupt deepening events followed by prolonged upward shallowing. Deepening events in the western United States (especially Nevada), western Canada, New York, Belgium, and Germany have been dated in the standard conodont zonation and are demonstrably simultaneous in several or all five regions. This synchroneity indicates control by eustatic sea-level fluctuations rather than by local or regional epeirogeny. Facies shifts in shelf sedimentary successions are more reliable indicators of the timing of sea-level fluctuations than are strandline shifts in the cratonic interior, because the latter are more influenced by local epeirogeny. Strandline shifts are most useful in estimating the relative magnitude for sea-level fluctuations. Devonian facies progressions and the three prominent regressions are of a duration and an order of magnitude that could have been caused by episodes of growth and decay of Devonian oceanic ridge systems. The described T-R cycles could have formed in response to mid-plate thermal uplift and submarine volcanism. The latter process may have been a control on small-scale (1–5 m thick), upward-shallowing cycles within the major T-R cycles. Continental glaciation could have been a factor in sea-level fluctuations only in the Famennian and could not have been responsible for the Devonian facies progressions or the numerous T-R cycles. The Frasnian extinctions were apparently cumulative rather than due to a single calamity. Two rapid sea-level rises occurred just before, and one at, the Frasnian-Famennian boundary. It is probable that this series of deepening events reduced the size of shallow-shelf habitats, caused repeated anoxic conditions in basinal areas, and drowned the reef ecosystems that had sustained the immensely diverse Devonian benthos.

Computer-Based Instruction: Methods and Development

Abstract: I.COMPUTER-BASED INSTRUCTION METHODOLOGIES. 1.Introduction. 2.Tutorials. 3.Drills. 4.Simulations. 5.Instructional Games. 6.Tests. II.DEVELOPMENT OF COMPUTER-BASED INSTRUCTION. 7.Preparation. 8.Design. 9.Flowcharting. 10.Storyboarding. 11.Programming and Support Materials. 12.Evaluation. III.ADVANCED TOPICS IN COMPUTER-BASED INSTRUCTION. 13.Computer-Managed Instruction. 14.Interactive Video. 15.Artificial Intelligence in Instruction. Appendices.

Knowledge without awareness: an autonomic index of facial recognition by prosopagnosics

Abstract: Prosopagnosia, the inability to recognize visually the faces of familiar persons who continue to be normally recognized through other sensory channels, is caused by bilateral cerebral lesions involving the visual system. Two patients with prosopagnosia generated frequent and large electrodermal skin conductance responses to faces of persons they had previously known but were now unable to recognize. They did not generate such responses to unfamiliar faces. The results suggest that an early step of the physiological process of recognition is still taking place in these patients, without their awareness but with an autonomic index.

Transluminal, subselective measurement of coronary artery blood flow velocity and vasodilator reserve in man.

Abstract: Assessment of coronary blood flow and the vasodilator reserve capacity of individual coronary arteries in the catheterization laboratory has been hampered by methodologic limitations. We have developed and validated a small Doppler catheter that can subselectively measure phasic coronary blood flow velocity (CBFV). In seven anesthetized calves, CBFV was varied from 0.1 to 5.7 times control CBFV. Changes in mean CBFV measured intraluminally by catheter in the left anterior descending and left circumflex arteries were similar to those measured simultaneously with an epicardial Doppler probe on the surface of the same vessel (n = 85, r = .95, slope = 1.04) and to changes in coronary sinus flow (n = 69, r = .97, slope = 1.06) measured with timed venous collections. Identical maximal coronary reactive hyperemic responses with the catheter present and absent in the artery being studied demonstrated that coronary obstruction by the catheter was minimal. Safety studies in six additional calves demonstrated that the catheter caused small changes in coronary endothelial permeability. Histologic studies revealed no endothelial denudation or thrombus formation. Stable phasic recordings of coronary blood flow velocity have been obtained in 58 of 70 patients studied. One of the 70 patients studied had abrupt coronary occlusion probably related to catheter-induced vasospasm. In 10 normal patients, intracoronary meglumine diatrizoate increased CBFV to 3.5 times that at rest (range 2.8 to 5.0). CBFV rose 5.0-fold after an intravenous infusion of dipyridamole (range 3.8 to 7.0). In each patient, dipyridamole produced greater vasodilation than meglumine diatrizoate. The time- and dose-response characteristics to dipyridamole infusion were heterogeneous, underscoring the advantage of continuous on-line measurement of CBFV in the measurement of vasodilator reserve. This method of measuring CBFV and assessing vasodilator reserve in the catheterization laboratory should facilitate studies of the coronary circulation in man.

A study of mathematical programming methods for structural optimization. Part I: Theory

Abstract: A comprehensive study of various mathematical programming methods for structural optimization is presented. In recent years, many modern optimization techniques and convergence results have been developed in the field of mathematical programming. The aim of this paper is twofold: (a) to discuss the applicability of modern optimization techniques to structural design problems, and (b) to present mathematical programming methods from a unified and design engineers' viewpoint. Theoretical aspects are considered here, while numerical results of test problems are discussed in a companion paper. Special features possessed by structural optimization problems, together with recent developments in mathematical programming (recursive quadratic programming methods, global convergence theory), have formed a basis for conducting the study. Some improvements of existing methods are noted and areas for future investigation are discussed.

Early Consequences of Seed Dispersal for a Neotropical Tree (Virola surinamensis)

Abstract: We examined the effects of distance from a fruiting conspecific, light environment, and initial seed size on survivorship using Virola surinamensis seeds and seedlings placed in concentric rings around fruiting Virola trees. Insects and mammals killed 99.2% of seeds and seedlings between fruit drop and exhaustion of parental endosperm at 12 wk after germination. During this time, survival was not influenced by either seed size or light environment, but up to a 44-fold advantage accrued to seeds dropped 45 m from a fruiting tree as compared with those underneath Virola crowns. Seeds that germinated under and near fruiting Virola trees suffered disproportionate attack from a curculionid weevil {Conotrachelus sp. nov.). Both large initial seed size and favorable light environments (assessed by canopy photographs) enhanced seedling vigor at 18 wk of age. Among those seedlings that escaped predation beyond the exhaustion of parental seed stores, a difference of as little as 1% in the amount of canopy open overhead distinguished seedlings with three leaves (3.5% open) from those with two leaves (2.3% open). Our results demonstrate clear advantages to local seed dispersal for a tree ofthe rainforest canopy. They further suggest that dispersal of seeds > 20 m by large birds, such as guans {Penelope purpurascens) and toucans {Ramphastos sulfuratus and R. swainsonii), is more favorable for seedling survival than that of the smaller trogons (Trogon massena) and motmots {Baryphthengus martii), which regurgitate seeds under or near the tree crown.

Amnesia Following Basal Forebrain Lesions

Abstract: • Of five patients with damage to the basal forebrain, four had lesions secondary to rupture of anterior cerebral or anterior communicating artery aneurysms, and one to the resection of an arteriovenous malformation. Computed tomographic scans and intraoperative reports confirmed damage to basal forebrain regions, which include septal nuclei, nucleus accumbens, substantia innominata, and related pathways. Behavioral disturbances featured a prominent amnesic syndrome and personality changes. The amnesia was distinguishable from that reported in patients HM and DRB and shared features with that seen in patients with Korsakoff's syndrome. We propose that the memory disorder can be explained by malfunctioning in the hippocampal system, secondary to damage in the basal forebrain structures with which it is strongly interconnected. The dysfunction might, in part, be caused by reduction of specific neurotransmitter innervation because the lesions are likely to damage cholinergic neurons and nearby catecholamine pathways within the basal forebrain.

A Structured Interview for the DSM-III Personality Disorders: A Preliminary Report

Abstract: • With few exceptions, published studies fail to indicate that theDSM-IIIpersonality disorders can be distinguished from each other with respect to etiology, prognosis, treatment response, or family history. The Structured Interview for theDSM-IIIPersonality Disorders (SIDP) was developed to improve axis II diagnostic reliability, and hence allow validity testing of axis II. Sixty-three subjects were independently rated by two interviewers using the SIDP. The k coefficients for interrater agreement reached .70 or higher for histrionic, borderline, and dependent personalities. While it is impossible to separate the validity testing of the SIDP from validity testing of theDSM-IIIpersonality criteria themselves, preliminary results from 102 inpatient SIDP interviews suggest some criterion-based validity with respect to standard personality rating scales and some construct validity with respect to the dexamethasone suppression test.

High-frequency switching of colony morphology in Candida albicans

Abstract: The pathogenic yeast Candida albicans switches heritably and at high frequency between at least seven general phenotypes identified by colony morphology on agar. Spontaneous conversion from the original smooth to variant phenotypes (star, ring, irregular wrinkle, hat, stipple, and fuzzy) occurs at a combined frequency of 1.4 X 10(-4), but is increased 200 times by a low dose of ultraviolet light that kills less than 10 percent of the cells. After the initial conversion, cells switch spontaneously to other phenotypes at a combined frequency of 2 X 10(-2). Switching is therefore heritable, but also reversible at high frequency. The genetic basis of this newly discovered process and its possible role in Candida pathogenesis are considered.

Structure and Regulation of the Corpus Allatum

Abstract: Publisher Summary This chapter discusses the structure and regulation of the corpus allatum. The corpora allata (CA) are endocrine glands in the posterior regions of the head, or in rare instances in the thorax, which are closely associated with the stomatogastric nervous system. This chapter focuses on the regulation of the CA. It also describes the embryology, innervations, and the relationships of the structure, particularly the ultrastructure, to its synthetic activity. The characteristic shape of the CA is ovoid to round but they may be elongate as in large larvae and adults of Libellula depressa. The size of the glands is frequently about the diameter of the aorta or smaller; however, there is much variation among species and even within a species, size differs with age, sex, polymorphism, and the activity cycle of the glands. Although only one type of glandular cell occurs in the CA, there are a variety of types of CA with respect to the number of cells per gland and the relative size of the cells. The CA are surrounded by a continuous noncellular basal lamina, roughly 0.1-1 μ m thick. This material occasionally projects between two glandular cells into the interior of the gland, forming trabeculae that may accompany nerves and trachea.

Alcoholism and antisocial personality. Interrelationships, genetic and environmental factors.

Abstract: • In a sample of 127 male and 87 female adult adoptees, antisocial personality and alcohol abuse were related to biologic backgrounds and to environmental factors. In the men, alcohol abuse was increased by a background of problem drinking in first-degree biologic relatives and by drinking problems in the adoptive home. Antisocial personality occurred more frequently in men whose first-degree biologic relatives had antisocial behavior problems. In the women, alcohol abuse was increased in adoptees whose first-degree relatives had problem drinking. Increased alcohol abuse in men and women was not predicted by biologic first-degree relatives with antisocial problems, nor did increased frequency of antisocial personality occur in adoptees with biologic relatives with problem drinking. The results suggest specificity of inheritance of antisocial and alcoholic conditions and the importance of environmental factors.

Multimodal Amnesic Syndrome Following Bilateral Temporal and Basal Forebrain Damage

Abstract: • A 55-year-old right-handed man (patient DRB) had a major amnesic syndrome following extensive bilateral damage to the temporal lobe and basal forebrain, caused by herpes simplex encephalitis. His amnesia was both anterograde and retrograde. The retrograde amnesia spanned the five decades of his life, sparing only generic (semantic) material and shreds of previous experiences devoid of appropriate temporal and spatial placement. The anterograde amnesia encompassed both generic (semantic) and contextual (episodic) material. With the exception of preserved learning of a visuomotor skill, the patient did not show acquisition of any new information since his illness in 1975. Elementary perceptual, intellectual, and linguistic abilities remained intact. Because several anatomic and behavioral characteristics of this case are different from those of previously reported cases of amnesia, they may provide new insight into the neuroanatomic substrate of human memory.

Nonhaemorrhagic thalamic infarction. Clinical, neuropsychological and electrophysiological findings in four anatomical groups defined by computerized tomography.

Abstract: Twenty-five patients with nonhaemorrhagic infarcts of the thalamus were studied clinically and by neuropsychological testing, computerized tomography and somatosensory evoked response (SER) recordings. Our aim was to determine whether the findings in these different tests would form distinct symptom clusters associated with different anatomical territories of the thalamus. Infarction conforming to the tuberothalamic arterial territory caused a facial paresis for emotional movements, severe neuropsychological deficits and a delay of the SER after P14. Infarction conforming to the interpeduncular profundus arterial territory caused a supranuclear vertical gaze paresis, severe neuropsychological deficits and a delay in the P60 component of the SER. Infarction conforming to the anterior choroidal territory caused a hemiparesis, moderate neuropsychological deficits and varied sensory evoked responses. Patients with infarctions conforming to the entire geniculothalamic territory had sensory loss in multiple modalities, minimal neuropsychological deficits and absence of sensory evoked responses after P14. A lacune in this territory caused pure hemisensory loss involving part of the body for the modalities of pain and light touch but not proprioception or vibration. Neuropsychological deficits were uncommon and N32 and N60 were delayed in the SER.

Toward an analysis of the role of gay communities in the urban renaissance

Abstract: This paper provides a theoretical and methodological framework for a "social constructionist" analysis of the role of gay communities in the "urban renaissance." We suggest that this is important both because as a substantive area of research the role of gays in the "urban renaissance" has been neglected, and because it highlights the need to overcome the structure versus agency debate in social theory. Structuralists have tended to regard the role of cultural identity in the "urban renaissance" asepiphenomenal, while voluntarists have regarded it as indicative only of personal choices in "lifestyles." An analysis of the social construction of the gay identity is stipulated, and an argument is made that gay involvement in the "urban renaissance" constitutes part of a spatial response to a historically specific form of oppression. An enumeration of what needs to be done to more fully implement our approach is provided.

Explaining Challenger Quality in Congressional Elections.

Abstract: This study seeks to explain why some incumbents attract politically experienced, well-financed challengers while others do not. Using data from contested House races in 1980, we analyze the effects of four sets of variables including: (1) incumbents' policy and nonpolicy behavior (ideological discrepancy and use of "perks" for advertising and casework); (2) local partisan conditions (previous vote margin and the normal partisan vote in the district); (3) district diversity; and (4) the national tide. We find that both short-term and long-term partisan forces (previous vote and normal vote), national tides, and policymaking behavior (ideological discrepancy) significantly affect the probability of attracting politically experienced, well-financed challengers. District diversity and incumbents' use of "perks" available for advertising and casework, on the other hand, are not related to any indicator of challenger quality.

Private acts and public objects: An investigation of citer motives

Abstract: Citation analysis has been used as a method for evaluating scholars and their impact. Evaluative citation analysis has been employed without a clear understanding of why authors give references and in the absence of any empirical work investigating citer motivations. The debate over the validity of evaluative citation analysis derives from the competing theoretical models used to describe the citer's motivations. Current models describing citer motivations were analyzed in this article and the seven most significant citer motivations identified. These seven citer motivations were presented to 26 authors at the University of Iowa each of whom had recently published an academic article. The authors indicated their motivations for giving each reference in their articles. As a result, the motivational background for more than 900 citational acts were gathered and analyzed.

The Reliability and Validity of an Instrument for the Assessment of Computer Attitudes

Abstract: As computer-related programs are introduced into school curricula, it is helpful to evaluate teacher attitudes toward computer use which may affect the success of such programs. Involving 114 teachers enrolled in microcomputer staff development courses, this study was concerned with the reliability, the factorial validity, and the differential validity of the Computer Attitude Scale and its four subscales (Computer Anxiety, Computer Confidence, Computer Liking, and Computer Usefulness). This instrument was found to be reliable in measuring teachers' attitudes toward computers and effective in differentiating among teachers with different amounts of computer experience.

The lower central series of a fiber-type arrangement.

Abstract: For a certain class (“fiber-type”) of arrangements, including the supersolvable ones of Jambu and Terao [3], we prove a formula relating the Poincare polynomial of the complement with the ranks of successive quotients in the lower central series of the fundamental group. Such a formula was proved by Kohno [5] for the single family of examplesA l . We also show that the formula doesnot hold for allK(π, 1) arrangements.

Myelodysplastic syndromes. A clinical and pathologic analysis of 109 cases

Abstract: A total of 109 patients with myelodysplastic syndromes (MDS) was analyzed to determine the clinical and pathologic features of the five recently defined French-American-British Cooperative Group (FAB) subtypes, and to assess the utility of this classification system in predicting survival, evolution to acute nonlymphocytic leukemia (ANLL), and cause of death All patients with MDS presented with anemia; additional cytopenias were present in patients with refractory anemia with excess blasts (RAEB), chronic myelomonocytic leukemia (CMML) and refractory anemia with excess blasts in transformation to ANLL (RAEB/Tr) Thirty-two patients received some form of antileukemic therapy for MDS ANLL developed in 16 of the 77 remaining untreated patients, including 18% (2/11), 0% (0/21), 22% (5/23), 33% (2/6), and 44% (7/16) of patients with refractory anemia (RA), refractory anemia with ring sideroblasts (RARS), RAEB, CMML, and RAEB/Tr, respectively (P = 002) The FAB subtype was highly predictive of survival with median survivals ranging from 71 months for RARS to 5 months for RAEB/Tr (P = less than 00001) Patients with RAEB, CMML, and RAEB/Tr frequently died of direct consequences of MDS, while patients with RA and especially RARS generally survived or died from unrelated disorders (P = less than 00001) MDS encompass a spectrum of disorders RA and RARS, are relatively indolent and often do not lead to the patient's demise RAEB, CMML, and RAEB/Tr are aggressive disorders which are often responsible for the patient's death whether or not actual progression to overt leukemia occurs FAB subtype predicts survival, evolution to ANLL, and cause of death, although the five morphologic subtypes appear to separate into only two disease groups, especially with regard to survival and cause of death

PACs, Contributions, and Roll Calls: An Organizational Perspective

Abstract: This study uses information about the organizational arrangements of five major political action committees to develop an explanation for the extent to which PAC contributions are capable of influencing congressional voting decisions. The explanation claims that the processes by which PACs raise and allocate money must be understood before the impact of money on roll call decisions can be appreciated. In contrast to some previous studies, this analysis demonstrates with marked clarity the limited nature of PAC influence.

Neuropsychologic detection of abnormal mental decline in older persons.

Abstract: We conducted comprehensive neuropsychologic assessment in normal 60- to 88-year-old persons and in patients with dementia of various causes, matched for age and sex. Patients with dementia performed significantly poorer on tests of short-term memory, temporal orientation, visual perception, and language. Further data analysis, including multivariate classification procedures, identified a combination of three tests (Visual Retention, Controlled Oral Word Association, and Temporal Orientation) that in a cross-validation study correctly classified 89% of cases with a high degree of probability. Only 6.5% of cases were misclassified, while 4.5% were in a questionable, borderline category. The battery constituted by these three discriminating tests provides a brief, easily administered neuropsychologic screening instrument that may be used by a variety of health professionals for the detection of abnormal mental decline in older persons.

Age-related changes in the circadian rhythm of plasma cortisol in man.

Abstract: We studied the effect of age on the circadian rhythm of plasma cortisol in 34 normal subjects, aged 18-75 yr. Blood was sampled at 20-min intervals beginning at 2000 h, and the data were analyzed using the PULSAR program and the cosinor method. There was a negative correlation between age and the time of the maximum cortisol concentration (r = -0.548; P = 0.001), the time of the nadir cortisol concentration (r = -0.543; P = 0.001), and the acrophase (r = 0.528; P = 0.001). When the subjects were divided into those 39 yr of age and younger and 40 yr of age and older, the times of the cortisol nadir, maximum, and acrophase were significantly earlier in the older group. The interval between the nadir and peak cortisol levels was not significantly different, consistent with an age-related phase advance of the cortisol circadian rhythm. Quantitative indices of adrenal function, including the 24-h mean cortisol concentration and the number of cortisol peaks as well as their amplitude and duration, were not different in the two groups. There was a significant negative correlation between age and customary bedtime (r = -0.686; P = 0.001) that may explain, in part, the phase advance in the older subjects. This observation strengthens the evidence that sleep onset is a major factor contributing to synchronization of the cortisol rhythm. Alternative explanations are that age-related changes in the control of hormonal and other rhythms have important influences on sleep and activity schedules, or that sleep and cortisol variables do not influence each other, but are both the final expression of some central change.

Oral Discussion, Group-to-individual Transfer, and Achievement in Cooperative Learning Groups

Abstract: : The effects of cooperative learning in which oral discussion was structured (to ensure oral summarization and the monitoring of others' summaries), cooperative learning in which oral discussion was unstructured, and individualistic learning were compared on daily achievement, post-instructional achievement, and retention. Seventy-five second grade students were randomly assigned to the three conditions stratifying for sex and ability level. The results indicate that students in cooperative groups performed significantly higher on the accuracy of daily work than do students working individualistically. In addition, the high-, medium-, and low-ability students in the structured oral discussion cooperative condition scored higher on the post-instructional and retention tests (which were taken individually) than did the students in the other two conditions, and the students in the unstructured oral discussion cooperative condition scored higher on these tests did the students who had learned individualistically. These results indicate that group-to-individual transfer does take place within cooperative learning groups and that orally summarizing the material being learned and the monitoring of others' summaries contributes to the efficacy of cooperative learning. Keywords: Cooperation; Achievement; Oral Discussion.