Showing papers by "University of South Florida published in 1995"

The NURBS Book

Abstract: One Curve and Surface Basics.- 1.1 Implicit and Parametric Forms.- 1.2 Power Basis Form of a Curve.- 1.3 Bezier Curves.- 1.4 Rational Bezier Curves.- 1.5 Tensor Product Surfaces.- Exercises.- Two B-Spline Basis Functions.- 2.1 Introduction.- 2.2 Definition and Properties of B-spline Basis Functions.- 2.3 Derivatives of B-spline Basis Functions.- 2.4 Further Properties of the Basis Functions.- 2.5 Computational Algorithms.- Exercises.- Three B-spline Curves and Surfaces.- 3.1 Introduction.- 3.2 The Definition and Properties of B-spline Curves.- 3.3 The Derivatives of a B-spline Curve.- 3.4 Definition and Properties of B-spline Surfaces.- 3.5 Derivatives of a B-spline Surface.- Exercises.- Four Rational B-spline Curves and Surfaces.- 4.1 Introduction.- 4.2 Definition and Properties of NURBS Curves.- 4.3 Derivatives of a NURBS Curve.- 4.4 Definition and Properties of NURBS Surfaces.- 4.5 Derivatives of a NURBS Surface.- Exercises.- Five Fundamental Geometric Algorithms.- 5.1 Introduction.- 5.2 Knot Insertion.- 5.3 Knot Refinement.- 5.4 Knot Removal.- 5.5 Degree Elevation.- 5.6 Degree Reduction.- Exercises.- Six Advanced Geometric Algorithms.- 6.1 Point Inversion and Projection for Curves and Surfaces.- 6.2 Surface Tangent Vector Inversion.- 6.3 Transformations and Projections of Curves and Surfaces.- 6.4 Reparameterization of NURBS Curves and Surfaces.- 6.5 Curve and Surface Reversal.- 6.6 Conversion Between B-spline and Piecewise Power Basis Forms.- Exercises.- Seven Conics and Circles.- 7.1 Introduction.- 7.2 Various Forms for Representing Conics.- 7.3 The Quadratic Rational Bezier Arc.- 7.4 Infinite Control Points.- 7.5 Construction of Circles.- 7.6 Construction of Conies.- 7.7 Conic Type Classification and Form Conversion.- 7.8 Higher Order Circles.- Exercises.- Eight Construction of Common Surfaces.- 8.1 Introduction.- 8.2 Bilinear Surfaces.- 8.3 The General Cylinder.- 8.4 The Ruled Surface.- 8.5 The Surface of Revolution.- 8.6 Nonuniform Scaling of Surfaces.- 8.7 A Three-sided Spherical Surface.- Nine Curve and Surface Fitting.- 9.1 Introduction.- 9.2 Global Interpolation.- 9.2.1 Global Curve Interpolation to Point Data.- 9.2.2 Global Curve Interpolation with End Derivatives Specified.- 9.2.3 Cubic Spline Curve Interpolation.- 9.2.4 Global Curve Interpolation with First Derivatives Specified.- 9.2.5 Global Surface Interpolation.- 9.3 Local Interpolation.- 9.3.1 Local Curve Interpolation Preliminaries.- 9.3.2 Local Parabolic Curve Interpolation.- 9.3.3 Local Rational Quadratic Curve Interpolation.- 9.3.4 Local Cubic Curve Interpolation.- 9.3.5 Local Bicubic Surface Interpolation.- 9.4 Global Approximation.- 9.4.1 Least Squares Curve Approximation.- 9.4.2 Weighted and Constrained Least Squares Curve Fitting.- 9.4.3 Least Squares Surface Approximation.- 9.4.4 Approximation to Within a Specified Accuracy.- 9.5 Local Approximation.- 9.5.1 Local Rational Quadratic Curve Approximation.- 9.5.2 Local Nonrational Cubic Curve Approximation.- Exercises.- Ten Advanced Surface Construction Techniques.- 10.1 Introduction.- 10.2 Swung Surfaces.- 10.3 Skinned Surfaces.- 10.4 Swept Surfaces.- 10.5 Interpolation of a Bidirectional Curve Network.- 10.6 Coons Surfaces.- Eleven Shape Modification Tools.- 11.1 Introduction.- 11.2 Control Point Repositioning.- 11.3 Weight Modification.- 11.3.1 Modification of One Curve Weight.- 11.3.2 Modification of Two Neighboring Curve Weights.- 11.3.3 Modification of One Surface Weight.- 11.4 Shape Operators.- 11.4.1 Warping.- 11.4.2 Flattening.- 11.4.3 Bending.- 11.5 Constraint-based Curve and Surface Shaping.- 11.5.1 Constraint-based Curve Modification.- 11.5.2 Constraint-based Surface Modification.- Twelve Standards and Data Exchange.- 12.1 Introduction.- 12.2 Knot Vectors.- 12.3 Nurbs Within the Standards.- 12.3.1 IGES.- 12.3.2 STEP.- 12.3.3 PHIGS.- 12.4 Data Exchange to and from a NURBS System.- Thirteen B-spline Programming Concepts.- 13.1 Introduction.- 13.2 Data Types and Portability.- 13.3 Data Structures.- 13.4 Memory Allocation.- 13.5 Error Control.- 13.6 Utility Routines.- 13.7 Arithmetic Routines.- 13.8 Example Programs.- 13.9 Additional Structures.- 13.10 System Structure.- References.

The Infectivity of Cryptosporidium parvum in Healthy Volunteers

Abstract: Background Small numbers of Cryptosporidium parvum oocysts can contaminate even treated drinking water, and ingestion of oocysts can cause diarrheal disease in normal as well as immunocompromised hosts. Since the number of organisms necessary to cause infection in humans is unknown, we performed a study to determine the infective dose of the parasite in healthy adults. Methods After providing informed consent, 29 healthy volunteers without evidence of previous C. parvum infection, as determined by the absence of anti-cryptosporidium–specific antibodies, were given a single dose of 30 to 1 million C. parvum oocysts obtained from a calf. They were then monitored for oocyst excretion and clinical illness for eight weeks. Household contacts were monitored for secondary spread. Results Of the 16 subjects who received an intended dose of 300 or more oocysts, 14 (88 percent) became infected. After a dose of 30 oocysts, one of five subjects (20 percent) became infected, whereas at a dose of 1000 or more oocysts, ...

Going to Extremes: Managing Service Encounters and Assessing Provider Performance:

Abstract: The authors advance a framework for analysis and comparison of service encounters using three neglected dimensions—duration, affective content, and spatial proximity. They focus on service encounte...

Flow hydrodynamics in tidal marsh canopies

Abstract: The transport of particulate and dissolved matter on the surface of coastal marshes is controlled by the hydrodynamic characteristics of over-marsh flows. High-frequency (5 Hz) in situ measurements of flow speed were collected in Spartina alternijlora, Juncus roemerianus, and Di:-tichlis spicata canopies using hot-film anemometry sensor arrays. These data indicate that mean flow speed, turbulence intensity, and the shape of the vertical speed profile are influenced by variations in plant morphology and stem density. Mean flow speed and turbulence intensity are inversely related to stem density and to distance from the creek edge. Flow energies decrease by about one order of magnitude when flows encounter the vegetated marsh surface and continue to decrease as vegetation density increa,ses. Turbulent flow energy also decays exponentially with increasing distance from the creek edge. Reductions in flow speed coupled with energy decay provide a hydrologic mechanism for sediment deposition patterns commonly observed in marsh systems. Suspended matter transport is also affected by plant-flow interactions. Vertical flow structure is strongly influenced by canopy morphology (plant type and plant shape). Plant-flow interactions result in vertical speed profiles whose shapes deviate from the logarithmic profile typical in free-stream conditions and in the development of transitional flow regimes (i.e. neither laminar nor fully turbulent).

The structure of the presenilin 1 (S182) gene and identification of six novel mutations in early onset AD families

Abstract: Genetic linkage studies place a gene causing early onset familial Alzheimer's disease (FAD) on chromosome 14q24.3 (refs 1–4). Five mutations within the S182 (Presenilin 1: PS–1) gene, which maps to this region, have recently been reported in several early onset FAD kindreds5. We have localized the PS-1 gene to a 75 kb region and present the structure of this gene, evidence for alternative splicing and describe six novel mutations in early onset FAD pedigrees all of which alter residues conserved in the STM26 (Presenilin 2: PS-2) gene.

Consumers’ emotional responses to service encounters

Abstract: Reports on a study looking at dimensions of service provider performance that influence immediate emotional responses to service encounters, based on 914 service encounters. Identifies five service‐provider dimensions that are significant predictors of emotional response to services. Finds that different service‐provider dimensions influence positive as compared with negative emotional responses and that temporal duration and spatial intimacy of the encounter affect both the reported levels and relative importance of these service‐provider dimensions to emotional responses.

Development of body image, eating disturbance, and general psychological functioning in female adolescents: Covariance structure modeling and longitudinal investigations

Abstract: Objective: Covariance structure modeling (CSM) and longitudinal analyses were used to identify a possible causal sequence for factors that might lead to the development of body image and eating disturbance in adolescent females. Method: In Study 1, subjects were measured for level of obesity, perceived weight status, maturational timing, history of being teased about weight/size, body image, eating disturbance, and global psychological functioning. Study 2 was a systematic replication of Study 1 using different indices of body image and a more comprehensive assessment of eating disturbance. In Study 3, subjects from Study 1 were reassessed at a 3-year follow-up. Results: The findings from Study 1 indicated that level of obesity and perceived weight, but not maturational timing, had a directional influence on the other variables. In addition, teasing history was significantly related to the development of body image and eating disturbance. CSM and path analyses with Studies 2 and 3 data generally replicated and extended the results from Study 1. Discussion: These findings offer important insights into possible causal sequences for the development of body image and eating disturbance. © 1995 by John Wiley & Sons, Inc.

Bilateral fetal nigral transplantation into the postcommissural putamen in Parkinson's disease

Abstract: We performed fetal nigral transplantations in 4 Parkinson's disease (PD) patients. Solid grafts were bilaterally implanted into the postcommissural putamen using 3 to 4 donors per side aged 6 1/2 to 9 weeks postconception. Transplant deposits were separated by no more than 5 mm in three dimensions. Cyclosporine was employed for a total of 6 months. Patients were evaluated at baseline and at 1, 3, and 6 months postoperatively. Striatal 18-fluorodopa uptake was assessed by positron emission tomography at baseline and at 6 months postoperatively. The procedure was well tolerated in all patients. One patient had a clinically asymptomatic superficial cortical hemorrhage along the needle tract and a second had transient postoperative confusion and hallucinations. All patients experienced clinically meaningful benefit. Significant improvement (p < 0.05) was detected in total UPDRS score during the „off” state, Schwab-England disability score during the „off” state, percent „off” time, and percent „on” time with dyskinesia. Increased striatal fluorodopa uptake was observed bilaterally in each patient, with mean increases of 53% on the right (p = 0.01) and 33% on the left (p = 0.08). Our study demonstrated clear and consistent improvement in clinical features and striatal fluorodopa uptake following fetal tissue transplantation in patients with advanced PD whose condition was not improved preoperatively by drug manipulation. These preliminary results are encouraging and support further studies to evaluate grafting strategies as a therapy for PD.

Measuring the Experience, Expression, and Control of Anger

Abstract: (1995). Measuring the Experience, Expression, and Control of Anger. Issues in Comprehensive Pediatric Nursing: Vol. 18, No. 3, pp. 207-232.

Information technology innovations: a classification by IT locus of impact and research approach

Abstract: Research based on diffusion of innovation (DOI) theory investigates the evaluation, adoption, and implementation of innovations. Gaining understanding is difficult when tracing results on a study-by-study basis. To remove some of the barriers to comparison of results, we distinguish between innovations according to their locus of impact (IS unit, intra- or inter-organizational) and between studies according to research approach (factor or stage).A representative sample of 70 information technology (IT) related DOI research studies published by IT researchers over the last decade is evaluated using this classification scheme. From the analysis, it appears that the classification scheme may be used to provide a clearer understanding of IT innovation diffusion.Traditional DOI theory appears to be most applicable to ITs which have an intra-organizational locus of impact. ITs with an information system (IS) unit locus of impact appear to require less organizational support, and their extent of implementation appears to be related to nontraditional innovation characteristics such as functionality and efficiency. Inter-organizational locus of impact IT innovations, however, appear to be more affected by contextual and environmental variables, and their differences may be better explained by economic influence or critical mass theories.

The role of nucleotides in human nutrition

Abstract: Dietary NT are reported to have significant effects upon lymphoid, intestinal and hepatic tissues, and lipid metabolism (Table 3). The mechanism remains unknown, and the nutritional role of NT remains controversial. However, maintenance of the endogenous NT supply via de novo synthesis and salvage is metabolically costly. Preformed NT supplied by the diet may contribute to tissue NT pools and thus optimize the metabolic function of rapidly dividing tissues such as those of the gastrointestinal and immune systems. An exogenous source of NT may be particularly important for individuals whose dietary intake of NT is low and/or whose tissue needs are increased, for example, rapidly growing infants fed most cow's milk-based formulas and individuals with disease related immunosuppression, intestinal, or liver injury. Under these conditions, dietary NTs may play a role as conditionally essential nutrients. In addition to serving as nucleic acid precursors, NTs and their related metabolic products are potent inter- and intracellular biological mediators. Certain effects of dietary NT may relate to one or more of these important functions. Area for future study include: 1. 1. The absorption and metabolism of nucleic acids, NTs, NSs, bases, and related metabolic products in humans, and the effects of age and disease upon these activities. 2. 2. Dietary NT effects upon gut-associated lymphoid tissues. 3. 3. The content of nucleic acid, NTs, NSs, bases, and their related metabolic products in human milk. 4. 4. The relative contribution of nucleic acid, NTs, NSs, and free bases to observed biologic effects, and the effects of individually administered purine and pyrimidine compounds.

The perception of Teasing scale (POTS) : a revision and extension of the Physical Appearance Related Teasing Scale (PARTS)

Abstract: This article describes the development and validation of a revised measure for the assessment of history of being teased about physical appearance. Study 1 involved the preliminary psychometric evaluation of the questionnaire on a sample of 227 college women, Two factors emerged: Weight-Related Teasing (WT) and Teasing About Abilities/Competencies (Competency Teasing; CT). The integrity of the factor structure of these two scales was established in Study 2 with a sample of 87 college women. Internal consistency ratios in this sample were also found to be acceptable. In Study 3, 92 college women were administered measures of body image, eating disturbance, and self-esteem to test for convergence with the Perception of Teasing Scale. Subjects also rated teasing items for frequency and effect (e.g., how upset they were by the teasing). Two-week test-retest reliabilities for these measures were acceptable. Weight-Related Teasing correlated to a greater degree with other measures than Competency Teasing. Regression analyses revealed the importance of a frequency versus effect dimension. Findings are discussed in light of recent research on developmental factors in body image and eating disturbance.

Critical comments on applying covariance structure modeling

Abstract: Covariance structure modeling, also known as structural equation modeling or causal modeling, appears increasingly popular. Such techniques can be used to conduct tests of complex theory on empirical data. To conduct such tests, researchers need measures of known factor structure and the knowledge of structural relations among the constructs of interest. Researchers typically have neither the required measures nor the knowledge of structural relations. Instead of conducting tests of theory, researchers use covariance structure models to develop measurements and theoretical models. This paper discusses why such use of covariance structure models is unlikely to produce scientific progress and proposes some alternative procedures thought to be more fruitful.

The effect of deprenyl and levodopa on the progression of Parkinson's disease

Abstract: We have performed a 14-month, prospective, randomized, double-blind, placebo-controlled study to evaluate the effect of deprenyl and levodopa/carbidopa (Sinemet) on the progression of signs and symptoms in patients with mild Parkinson's disease (PD). One hundred one untreated PD patients were randomly assigned to one of the following four treatment groups: Group I, deprenyl + Sinemet; Group II, placebo-deprenyl + Sinemet; Group III, deprenyl + bromocriptine; and Group IV, placebo-deprenyl + bromocriptine. The final visit was performed at 14 months, i.e., 2 months after withdrawal of deprenyl or its placebo and 7 days after withdrawal of Sinemet or bromocriptine. Deterioration in Unified Parkinson's Disease Rating Score (UPDRS) between untreated baseline and final visits was used as an index of disease progression. Placebo-treated patients deteriorated by 5.8 +/- 1.4 points, while deprenyl-treated patients deteriorated by 0.4 +/- 1.3 points (p < 0.001). This effect was sufficiently powerful that a significant deprenyl effect could be detected in the subgroup of 41 patients randomized to Sinemet (p < 0.01) as well as in the 23 patients who completed a 14-day washout of Sinemet or bromocriptine (p < 0.05). No difference in the extent of deterioration was detected in patients randomized to Sinemet versus bromocriptine. This study demonstrates that deprenyl attenuates deterioration in UPDRS score in patients with early PD. These findings are not readily explained by the drug's symptomatic effects and are consistent with the hypothesis that deprenyl has a neuroprotective effect.

Markov random field for tumor detection in digital mammography

Abstract: A technique is proposed for the detection of tumors in digital mammography. Detection is performed in two steps: segmentation and classification. In segmentation, regions of interest are first extracted from the images by adaptive thresholding. A further reliable segmentation is achieved by a modified Markov random field (MRF) model-based method. In classification, the MRF segmented regions are classified into suspicious and normal by a fuzzy binary decision tree based on a series of radiographic, density-related features. A set of normal (50) and abnormal (45) screen/film mammograms were tested. The latter contained 48 biopsy proven, malignant masses of various types and subtlety. The detection accuracy of the algorithm was evaluated by means of a free response receiver operating characteristic curve which shows the relationship between the detection of true positive masses and the number of false positive alarms per image. The results indicated that a 90% sensitivity can be achieved in the detection of different types of masses at the expense of two falsely detected signals per image. The algorithm was notably successful in the detection of minimal cancers manifested by masses /spl les/10 mm in size. For the 16 such cases in the authors' dataset, a 94% sensitivity was observed with 1.5 false alarms per image. An extensive study of the effects of the algorithm's parameters on its sensitivity and specificity was also performed in order to optimize the method for a clinical, observer performance study. >

Molecular aspects of implantation: The signals and molecular pathways involved in implantation, a symbiotic interaction between blastocyst and endometrium involving adhesion and tissue invasion

Abstract: Implantation is a complex process requiring the interaction of the blastocyst, and subsequently the developing embryo with the endometrium. Initially, the detailed cellular interactions implicated in this process were defined. More recently, many signals and molecular pathways are recognized that induce, or regulate the complex series of interactions required for implantation. In this review, the cellular and molecular interactions that take place during implantation are discussed.

A mutation in Alzheimer's disease destroying a splice acceptor site in the presenilin-1 gene.

Abstract: A series of mutations has been reported in the presenilin-1 (PS-1) gene which cause early onset Alzheimer's disease (AD). The mutations reported to date have encoded missense mutations which alter residues conserved between PS-1 and the presenilin-2 (PS-2) gene. We have recently determined the intron/exon structure of the PS-1 gene and this information has been used to identify a mutation in the splice acceptor site for exon 9 in a family with early onset AD. Amplification of cDNA from lymphoblasts of affected individuals revealed that the effect of the mutation was to cause splicing out of exon 9, however it does not change the open reading frame of the mRNA. The importance of this observation is discussed.

Elevated body swing test: a new behavioral parameter for rats with 6- hydroxydopamine-induced hemiparkinsonism

Abstract: Parkinson's disease is characterized by a depletion of dopamine (DA) neurons in the nigrostriatal pathway. Stereotaxic injections of 6- hydroxydopamine (6-OHDA), a selective neurotoxin, into either the medial forebrain bundle or the substantia nigra result in a massive DA denervation of the nigrostriatal pathway. Following unilateral nigrostriatal DA depletion, hemiparkinsonian animals develop a stereotypical rotational behavior when challenged with DA agonists such as apomorphine. The drug-induced rotational behavior has been widely used as the behavioral index of hemiparkinsonian animals, but it has some limitations. Although asymmetries in the rotational behavior may indicate an imbalance of DA contents and release capacity in the bilateral nigrostriatal pathway, the behavior is a pharmacological reaction. Accordingly, the drug-induced rotation test is subject to sensitization effects. The present study proposes the elevated body swing test (EBST) as a measure of asymmetrical motor behavior of hemiparkinsonian animals in a drug-free state. The EBST simply involves elevating the animal by handling its tail and recording the frequency and direction of the swing behavior. Unilateral nigral 6-OHDA-lesioned rats exhibited significant biased swing activity with the direction contralateral to the lesioned side, corresponding to the direction of apomorphine-induced rotations. A 30 sec EBST was noted as the peak time for biased swing activity. At 7 d postlesion (the start of testing), and every week thereafter for a period of 2 months, a fairly stable biased swing activity level was observed. At 1 and 2 months postlesion, the same animals were also challenged with apomorphine.

Cross-Arc Geochemical Variations in the Kurile Arc as a Function of Slab Depth

Abstract: Lavas from transects across the Kurile Islands arc showed geochemical variations related to changes in the compositions of fluids derived from the subducting slab. Enrichment factors for boron, cesium, arsenic, and antimony, all elements with strong affinities for water, decreased across the arc. This decrease is presumably related to losses of water-rich fluids during the dehydration of the subducting plate. Enrichments of potassium, barium, beryllium-10, and the light rare earth elements remained constant; these species may move in silica-rich fluids liberated from the slab at greater depths.

Everyday Market Helping Behavior

Abstract: Research in marketing includes many examples of consumers helping other consumers. However, most research has studied helping behavior from the recipients’ perspective by examining the use of perso...

Five methods for computing significant individual client change and improvement rates: support for an individual growth curve approach.

Abstract: Interest has been renewed in methods for determining individual client change. Currently, there are at least 4 pretreatment-posttreatment (pre-post) difference score methods. A 5th method, based on a random effects model and multiwave data, represents a growth curve approach and was hypothesized to be more sensitive to detecting significant (p < .05) change than the pre-post methods. The change rates produced by the 5 methods were compared in a sample of 73 older outpatients with 3 to 5 assessments per client on a measure of well-being (H. J. Dupuy, 1977). Results indicated that the growth curve approach improvement rate was the highest (68.5%). The growth curve and the Edwards-Nunnally (63.0%) methods produced significantly (p < .05) higher improvement rates than the other 3 methods, with 1 exception.

Acute Pancreatitis Induces Intrapancreatic Tumor Necrosis Factor Gene Expression

Abstract: Objective: To examine the intrapancreatic production of tumor necrosis factor (TNF) α and define its cell of origin during acute pancreatitis. Design: Acute necrotizing pancreatitis was induced in adult male mice by administering cerulein (50 μg/kg intraperitoneally four times over 3 hours). Animals were killed at 0, 0.5, 1, 2, 4, 6, and 8 hours, with the severity of pancreatitis established by blind histologic grading and serum amylase, lipase, and TNF levels. The expression of TNF messenger RNA within the pancreas was established by the reverse transcription polymerase chain reaction. Intrapancreatic TNF protein was analyzed by enzyme-linked immunosorbent assay, Western blot, and immunohistochemical methods. Results: Acute pancreatitis was manifest within 1 hour of the first cerulein injection and increased in severity through 8 hours. There was no constitutive expression of TNF messenger RNA within the pancreas, but transcripts were induced within 30 minutes following the onset of pancreatitis, increasing through 4 hours. Intrapancreatic and serum TNF peptide levels became detectable at 1 hour and increased over 6 hours (both P P P Conclusions: Tumor necrosis factor gene expression is induced locally during acute pancreatitis, resulting in large amounts of intrapancreatic TNF with levels consistently higher than those found in the serum. The overall rise in both tissue and serum TNF concentrations correlates directly with the severity of pancreatic damage and inflammation. The infiltrating macrophage appears to contribute most to this process. (Arch Surg. 1995;130:966-970)