ABSTRACT
Triadic distance models can be used to analyse proximity data defined on triples of objects. Three-way symmetry is a common assumption for triadic distance models. In the present study three-way symmetry is not assumed. Triadic distance models are presented for the analysis of asymmetric three-way proximity data that result in a simultaneous representation of symmetry and asymmetry in a low-dimensional configuration. An iterative majorization algorithm is developed for obtaining the coordinates and the representation of the asymmetry. The models are illustrated by an example using longitudinal categorical data.
Subject(s)
Algorithms , Models, Statistical , HumansABSTRACT
The hypothesis tested in this study is that judgments of the personality of unfamiliar target persons correspond better with the subject's Implicit Personality Theory (IPT) than judgments of the personality of familiar persons do. Each subject's IPT was individually assessed and represented using multidimensional scaling. Then judgments were obtained about three familiar and three unfamiliar target persons. The correspondence between a subject's IPT and his/her judgments about each target person was measured by fitting these judgments to the subject's IPT structure. This correspondence measure was significantly better for unfamiliar than for familiar targets. This result confirmed the hypothesis.
ABSTRACT
In patients with Parkinson disease, improved visualization of brain iron on a mid-field-strength magnet can be obtained with T2-weighted images and elimination of phase-encoding artifacts. A long echo delay time accentuates the loss of signal from brain iron. However, the long pulse sequence creates phase-encoding artifacts from CSF pulsations at the level of the basal ganglia. These artifacts are eliminated and resolving power increased with additional pulsing in the slice-selective and read gradients. Elimination of motion artifacts enhances visualization of brain iron in three ways: (1) extrapyramidal nuclei containing iron have better definition, (2) abnormalities are better identified, and (3) pseudolesions disappear. Our findings suggest there is significant improvement in the resolving power of brain iron on MR scans made with a mid-field-strength scanner when gradient modification is used.
Subject(s)
Brain/metabolism , Iron/metabolism , Magnetic Resonance Imaging/methods , Parkinson Disease/diagnosis , Adult , Aged , Humans , Middle AgedABSTRACT
An avulsion fracture on the dorsolateral aspect of the calcaneus at the origin of the extensor digitorum brevis muscle was identified after inversion injuries of the ankle. The avulsion occurred in 10% of emergency room patients with clinically suspected ankle fractures. The routine dorsoplantar view of the foot and/or the routine anteroposterior view of the ankle demonstrated the fracture. The fracture is most often confused with the os peroneum, or with the fracture of the anterior process of the calcaneus. Treatment is conservative with elevation, supportive bandage, and early activity.
Subject(s)
Calcaneus/injuries , Fractures, Bone/diagnostic imaging , Adolescent , Adult , Calcaneus/diagnostic imaging , Female , Fractures, Bone/therapy , Humans , Male , Middle Aged , RadiographyABSTRACT
A focal defect at the inferior margin of the right lobe of the liver was found in two patients with subhepatic abscesses. This defect must be differentiated from the porta hepatis and the gallbladder fossa. When technetium liver scans are obtained in patients with usspect abdominal abscesses, the inferior margin of the right lobe of the liver should be carefully scrutinized so that right subhepatic abscesses will not be overlooked.
Subject(s)
Liver Abscess/diagnostic imaging , Technetium , Abdomen , Adult , Diagnosis, Differential , False Negative Reactions , Gallium Radioisotopes , Humans , Male , Middle Aged , Radionuclide Imaging , UltrasonographyABSTRACT
Schistosomiasis of the spinal cord is a rare presentation of a disease involving over 200 million people. A patient from an endemic area presenting as a transverse myelitis or a spinal cord tumor, and with eosinophilia, should alert the physician to the possibility of schistosomiasis of the spinal cord. Diagnosis is based on finding the characteristic eggs in the stool or urine, or if necessary, by rectal, bladder or liver biopsies. Myelography is performed to determine if decompressive laminectomy is necessary.
