Systematic distortion of perceived three-dimensional structure from motion and binocular stereopsis.

The geometric relation between physical and perceived space as specified by binocular stereopsis and structure from motion was investigated. Four experimental tasks were used, each of which required a different aspect of three-dimensional (3-D) structure to be performed accurately. To examine whether the transformation between physical and perceptual space preserved the 3-D structural properties required to perform each of our tasks, the constancy of judged shape over changes in a depicted object's viewing distance or orientation was examined. Our results reveal that observers' judgments of 3-D shape from binocular stereopsis and motion contained systematic distortions: Perceived 3-D shape from motion was not invariant over orientation change and perceived 3-D structure from stereo, and motion and stereo in combination was not invariant over changes in viewing distance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Large induction motors-field test on locked rotor protection

Work carried out at PSE&G Company, Salem Nuclear-Generating Station, USA, to provide reliable locked rotor protection for large induction motors driving high inertial loads (i.e. reactor coolant pump motors) is reported. Experience in solving the problems associated with nuisance trips of the protection during startup is described. The protection scheme, test procedure and results are believed to be of considerable value to other utilities     

Giardia sp. cysts and infectious Cryptosporidium parvum oocysts in the feces of migratory Canada geese (Branta canadensis)

Fecal droppings of migratory Canada geese, Branta canadensis, collected from nine sites near the Chesapeake Bay (Maryland), were examined for the presence of Cryptosporidium parvum and Giardia spp. Cryptosporidium sp. oocysts were found in feces at seven of nine sites, and Giardia cysts were found at all nine sites. The oocysts from three sites were infectious for mice and molecularly identified as the zoonotic genotype of Cryptosporidium parvum. Waterfowl can disseminate infectious C. parvum oocysts in the environment.     

Perception of rigid motion in depth from the optical deformations of shadows and occlusion boundaries.

Three experiments were designed to examine the abilities of observers to determine an object's 3-dimensional structure and motion from various types of optical deformations. Observers were required to discriminate whether pairs of moving ellipsoids were rotating rigidly about a single axis or nonrigidly about different axes that varied in slant. Discrimination thresholds were significantly influenced by whether the ellipsoids were intersecting or nonintersecting and whether they contained identifiable texture elements. Performance was unaffected by precession movements of the axis of rotation, by increasing the number of intersecting ellipsoids beyond 2, or by replacing the deforming silhouettes with the projected motions of cast shadows presented in isolation against a planar background. Findings indicate that observers can perceive structure from motion based on several different types of optical deformation, including the deformations of shadows and silhouettes that do not contain identifiable features on which most existing theoretical analyses are designed to operate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of spatial luminance nonuniformities on visual-task performance and subjective uniformity

The objectives of the experiment described in the paper were the determination of the effects of nonuniformities on operator performance and perception, and the validation of current recommended standards. Subjects performed two tasks in the presence of nonuniformities: an objective visual search task, and a subjective magnitude-estimation task for the determination of perceived uniformity. The results indicated that the nonuniformities did not appreciably affect search performance, and that current recommendations are appropriate, although the magnitude-estimation task results indicated that the subjects were sensitive to the nonuniformities. The subjective impressions of perceived uniformity results follow the contrast threshold function of the visual system.     

Prostitution, violence, and posttraumatic stress disorder

One hundred and thirty people working as prostitutes in San Francisco were interviewed regarding the extent of violence in their lives and symptoms of posttraumatic stress disorder (PTSD). Fifty-seven percent reported that they had been sexually assaulted as children and 49% reported that they had been physically assaulted as children. As adults in prostitution, 82% had been physically assaulted; 83% had been threatened with a weapon; 68% had been raped while working as prostitutes; and 84% reported current or past homelessness. We differentiated the types of lifetime violence as childhood sexual assault; childhood physical abuse; rape in prostitution; and other (non-rape) physical assault in prostitution. PTSD severity was significantly associated with the total number of types of lifetime violence (r = .21, p = .02); with childhood physical abuse (t = 2.97, p = .004); rape in adult prostitution (Student's t = 2.77, p = .01); and the total number of times raped in prostitution (Kruskal-Wallace chi square = 13.51, p = .01). Of the 130 people interviewed, 68% met DSM III-R criteria for a diagnosis of PTSD. Eighty-eight percent of these respondents stated that they wanted to leave prostitution, and described what they needed in order to escape.     

Patients' self-reported functional status after granisetron or ondansetron therapy to prevent chemotherapy-induced nausea and vomiting at six cancer centers

Patient functional status after administration of either granisetron or ondansetron to prevent acute chemotherapy-induced nausea and vomiting (CINV) was studied. Pharmacists and nurses from six cancer centers distributed Functional Living Index-Emesis (FLIE) questionnaires to 115 outpatients receiving either granisetron or ondansetron for prevention of CINV. The emetogenic potential of each patient's chemotherapy regimen was high, moderately high, or moderate. Immediately before and 72 hours after chemotherapy, each patient rated his or her reaction to each of 18 items on the questionnaire on a 7-point scale. Possible scores ranged from 18 to 126, with higher scores indicating higher levels of functioning. The occurrence of nausea in the granisetron group was 40.0% compared with 43.2% in the ondansetron group; the occurrence of vomiting was 18.8% in the granisetron group and 11.1% in the ondansetron group. Patients who received highly emetogenic chemotherapy had significantly lower scores on the FLIE after chemotherapy than before. Patients with both nausea and vomiting reported a much higher negative impact on functional status after chemotherapy than those with nausea only. The mean prechemotherapy and postchemotherapy FLIE scores were 124.2 and 110.4 for granisetron and 124.9 and 111.9 for ondansetron. Granisetron and ondansetron did not differ significantly in their effect on functional status reported by patients before and 72 hours after receiving cancer chemotherapy.     

Oral contraceptives and risk of venous thromboembolism: impact of duration of use

BACKGROUND: At therapeutic dosage, cetirizine and ebastine induce significant inhibition of skin reactivity to histamine. The consistency of their efficacy, that is, efficacy with the least interindividual variability among subjects, has not been carefully assessed, however. OBJECTIVE: To compare the consistency and efficacy of these antihistamines on skin reactivity. METHODS: Twenty-four healthy volunteers participated in a randomized double-blind crossover study. The areas of wheals and flares induced by increasing (0, 5, 10, 50, 100, 200, and 300 mg/mL) histamine concentrations, administered by prick tests, were measured before and four hours after intake of 10 mg of each antihistamine, allowing concentration-response curves to be established. The threshold histamine concentrations inducing wheal areas of 3 mm2 (positivity) were calculated by interpolation. The coefficient of variation (SD/mean %) was used to evaluate the consistency of the response. RESULTS: Pretreatment concentration-response curves were similar, and threshold concentrations identical (0.29 mg/mL and 0.34 mg/mL for cetirizine and ebastine, respectively). For both, curves were lower after treatment than before. After cetirizine, the threshold concentration was significantly higher (217 mg/mL) than after ebastine (0.82 mg/mL) (P < .001), and total inhibition of the wheal reaction was observed in 21 of 24 patients at the lowest histamine concentration and in 17 of 24 at the highest. Ebastine never totally inhibited reaction, even to 5 mg/mL of histamine. Over the entire concentration-response curve, the coefficient of variation for the wheal reaction was 6.3% for cetirizine and 72.6% for ebastine, and, for flares, 11.0% and 83.7%, respectively. Hence, variability was much lower after cetirizine. CONCLUSION: Our study shows clearly that the efficacy of a single therapeutic dosage of cetirizine is consistently good for suppression of cutaneous reactivity to histamine in healthy volunteers. The need for ebastine to metabolize into the active carebastine might explain its lesser consistency.