Anomalies of motion perception in infantile esotropia

PURPOSE: To quantify motion sensitivity in patients with infantile esotropia who, as a subgroup, have been previously reported to have abnormal oculomotor control. In addition, to probe abnormal binocular development as a factor underlying abnormal motion perception in infantile esotropia (IE), motion sensitivity was compared among participants with and without stereopsis. METHODS: Monocular sensitivity to leftward and rightward motion was assessed across the horizontal meridian, using partially coherent random dot kinematograms. Participants included 11 observers with IE, 5 observers with acquired esotropia, and 11 observers with normal eye alignment. RESULTS: Participants with IE showed no deficits in motion sensitivity to any visual field locations when motion thresholds were collapsed across direction. However, they showed an abnormal variation in directional anisotropy. Although sensitivity to centripetal motion was superior in both hemifields of control participants and in the temporal hemifields of participants with IE, a centrifugal bias was revealed in the nasal hemifields of IE. Stereoblind observers with acquired esotropia showed a normal centripetal directional anisotropy, whereas binocular observers with acquired esotropia showed directional anisotropy similar to that in the IE group. CONCLUSIONS: Motion perception, like oculomotor function in IE, is characterized by a variation of directional anisotropy for stimuli presented to the nasal hemifields. This finding supports the hypothesis that abnormal oculomotor control and motion perception in IE reflect a common disruption of the visual system. A similar variation of directional sensitivity in patients with acquired esotropia with normal stereopsis suggests that the interruption of binocularity is not the underlying cause of abnormal motion perception in IE.     

Alteration of renal blood flow during epidural anesthesia in normal subjects

The cardiovascular consequences of epidural anesthesia secondary to sympathetic blockade are well documented; however, their repercussions on renal hemodynamics in humans have not been reported. We investigated the effect of epidural anesthesia on renal blood flow (RBF) in 13 healthy volunteers 18-45 yr of age. RBF was measured using paraaminohippurate clearance before and after bilateral T6 epidural sensory block (to ensure adequate sympathetic renal nerve blockade). Epidural anesthesia was established using 22 +/- 3 mL of 2% plain lidocaine (without epinephrine) via L1-L2 epidural catheter; urine output was measured using a three-way Foley catheter. Mean arterial pressure remained > or = 70 mm Hg in all subjects without any pharmacologic intervention. Mean RBF before epidural anesthesia was 16.1 +/- 6.8 mL.kg-1.min-1 and 14.3 +/- 2.9 mL.kg-1.min-1 after bilateral T6 epidural blockade. We conclude that the institution of epidural anesthesia in healthy subjects does not result in a significant change in RBF (P > 0.25).     

Cytologic diagnosis of anal intraepithelial neoplasia using smears and cytyc thin-preps

Because of inconsistencies in the literature regarding popliteus and its relation to the lateral meniscus, it was decided to investigate the influence on the behavior of the lateral meniscus of contraction of the popliteus muscle via arthroscopy. A series of 50 knees from 44 patients who underwent elective arthroscopic surgery were examined. During arthroscopy, popliteus was stimulated to contract using surface electrodes. Any resultant meniscal retraction was observed and recorded. Thirty-one knees showed such retraction, and no retraction was observed in the remaining 19 knees. The clinical implications of this study are limited, but the results may support a number of proposed theories. It may be concluded that in a population exhibiting normal, intact lateral menisci, popliteus variably acts as a retractor of the lateral meniscus.     

Estimating test-retest reliability in functional MR imaging. II: Application to motor and cognitive activation studies

Research on children's coping with homesickness during relatively uncontrollable separations has suggested that secondary control coping (i.e., adjusting oneself to fit objective conditions) is often preferred over primary control coping (i.e., modifying objective conditions to fit oneself). Related research suggests that negative affect is associated with (a) relinquishing control or using primary control to cope with uncontrollable stressors and (b) perceiving low control over stressors. The convergence of these factors was examined for the stressor of homesickness. Among 1,032 boys and girls spending 2 weeks at residential summer camps, the most frequent and effective way of coping with homesickness was to exert secondary control by engaging in a distracting physical activity. Contrary to speculation, the use of secondary control coping rose in adolescence. Congruent with empirical predictions, the most homesick children perceived low control over homesickness and separation, and coped by relinquishing control.     

Exposure Fusion for Time‐Of‐Flight Imaging

This work deals with the problem of automatically choosing the correct exposure (or integration) time for time‐of‐flight depth image capturing. We apply methods known from high dynamic range imaging to combine depth images taken with differing integration times in order to produce high quality depth maps. We evaluate the quality of these depth maps by comparing the performance in reconstruction of planar textured patches and in the 3D reconstruction of an indoor scene. Our solution is fast enough to capture the images at interactive frame rates and also flexible to deal with any amount of exposures.     

Study on IAC networks models: learning and stability

This paper presents a methodology that uses evolutionary learning in training ‘A’ model networks, a topology based on Interactive Activation and Competition (IAC) neural networks. IAC networks show local knowledge and processing units clustered in pools. The connections among units may assume only 1, 0 or −1. On the other hand, ‘A’ model network uses values in interval [−1, 1]. This feature provides a wider range of applications for this network, including problems which do not show mutually exclusive concepts. However, there is no algorithm to adjust the network weights and still preserve the desired characteristics of the original network. Accordingly, we propose the use of genetic algorithms in a new methodology to obtain the correct weight set for this network. Two examples are used to illustrate the proposed method. Findings are considered consistent and generic enough to allow further applications on similar classes of problems suitable for ‘A’ model IAC Networks.