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Subject's Ability (subject + ability)
Selected AbstractsStrain Differences in Behavioral Inhibition in a Go/No-go Task Demonstrated Using 15 Inbred Mouse StrainsALCOHOLISM, Issue 8 2010Noah R. Gubner Background:, High levels of impulsivity have been associated with a number of substance abuse disorders including alcohol abuse. Research has not yet revealed whether these high levels predate the development of alcohol abuse. Methods:, The current study examined impulsivity in 15 inbred strains of mice (A/HeJ, AKR/J, BALB/cJ, C3H/HeJ, C57BL/6J, C57L/J, C58/J, CBA/J, DBA/1J, DBA/2J, NZB/B1NJ, PL/J, SJL/J, SWR/J, and 129P3/J) using a Go/No-go task, which was designed to measure a subject's ability to inhibit a behavior. Numerous aspects of response to ethanol and other drugs of abuse have been examined in these strains. Results:, There were significant strain differences in the number of responses made during the No-go signal (false alarms) and the extent to which strains responded differentially during the Go and No-go signals (d,). The rate of responding prior to the cue did not differ among strains, although there was a statistically significant correlation between false alarms and precue responding that was not related to basal activity level. Interstrain correlations suggested that false alarms and rate of responding were associated with strain differences in ethanol-related traits from the published literature. Conclusions:, The results of this study do support a link between innate level of impulsivity and response to ethanol and are consistent with a genetic basis for some measures of behavioral inhibition. [source] Human Perception of Dental Porcelain Translucency Correlated to Spectrophotometric MeasurementsJOURNAL OF PROSTHODONTICS, Issue 3 2010Min-Chieh Liu DDS Abstract Purpose: This study evaluated the relationship between instrumental measurements and subjective visual assessment of differences in dental porcelain translucency. Materials and Methods: Unshaded feldspathic porcelain was used with controlled amounts of tin oxide to create two groups of 12-mm diameter disks with incremental changes in opacity. Contrast ratio (CR = Yb/Yw) was determined with a spectrophotometer, and used as a measure of porcelain translucency (Group A = 0.20 to 0.40; Group B = 0.6,0.8). Within each group, there were 14 specimens with 11 CRs. Three observer groups (first year dental students, residents, faculty with >10 years of shade matching experience) were recruited to assess the translucency between porcelain disks under two lighting conditions (reflected light, transmitted light). Each subject's ability to distinguish between specimens of differing translucency was determined. Descriptive statistics and three-way ANOVA followed by a post-hoc Tukey-Kramer test were used to evaluate the translucency perception threshold (TPT) of subjects (,= 0.05). Results: The overall mean TPT (,C) was 0.07, while 50% of the subjects could perceive a 0.06 CR difference between porcelain specimens. Three-way ANOVA revealed a significant difference in translucency perception among the observer groups (p < 0.0001), whereas the main effects for porcelain opacity (p= 0.3038) and lighting condition (p= 0.0645) were not significant, and no significant interactions were found. Post-hoc Tukey-Kramer test indicated that the mean TPT observed in the faculty group (,C = 0.04) was significantly lower than those observed in student (,C = 0.09) and resident groups (,C = 0.08), while there was no significant difference between students and residents. Conclusions: The overall mean TPT of all subjects was 0.07, and 50% of the study population perceived a 0.06 CR difference in translucency. Increased shade matching experience (,10 years) significantly improved the ability to perceive differences in translucency; however, neither the viewing condition nor porcelain opacity affected the perceived translucency threshold. [source] Quality of life in functional dyspepsia: responsiveness of the Nepean Dyspepsia Index and development of a new 10-item short formALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 2 2001N. J. Talley Background: The Nepean Dyspepsia Index is a reliable and valid measure of quality of life in functional dyspepsia, but responsiveness has been little studied. The Nepean Dyspepsia Index originally contained 42 items designed to measure impairment of a subject's ability to engage in relevant aspects of their life because of dyspepsia, and their enjoyment of these aspects; in addition, the individual importance of areas was assessed. It was subsequently shortened to 25 items, yielding five sub-scales. Aim: To test the Nepean Dyspepsia Index's responsiveness and develop a responsive, very short form. Methods: A randomized, double-blind controlled trial was performed in 589 patients with documented functional dyspepsia. Symptoms and quality of life were measured at baseline, 2 and 4 weeks. Responsiveness of the Nepean Dyspepsia Index quality-of-life section was evaluated by correlation with symptom scores and calculation of standardized changes in scores. Two items from each sub-scale which best represented the area of life (by factor loadings) were selected to create the 10-item short form (SF; short form-Nepean Dyspepsia Index). Internal consistency was assessed by Cronbach's alpha and responsiveness was assessed as above. Results: The Nepean Dyspepsia Index quality-of-life scales demonstrated excellent responsiveness to change in both the active and placebo arms (standardized response means all > 1.0). The Nepean Dyspepsia Index accounted for only 8% of the variance in percentage change in symptoms (by visual analogue scales), indicating that it was evaluating areas of life not covered by symptoms. The 10-item short form had adequate internal consistency (all scales , 0.70) and all strongly (and significantly) correlated with the long form sub-scales; it was also highly responsive. Conclusion: The Nepean Dyspepsia Index is a responsive disease-specific quality-of-life measure; the 10-item short form can be applied in clinical trials of functional dyspepsia. [source] Sand flea (Tunga spp.) infections in humans and domestic animals: state of the artMEDICAL AND VETERINARY ENTOMOLOGY, Issue 3 2009S. PAMPIGLIONE Abstract. Tungiasis is a parasitic disease of humans and animals caused by fleas (Siphonaptera) belonging to the genus Tunga. Two species, Tunga penetrans (L.) and Tunga trimamillata, out of 10 described to date, are known to affect man or domestic animals; the other eight are exclusive to a few species of wild mammals. Tunga penetrans and T. trimamillata originated from Latin America, although the first species is also found in sub-Saharan Africa (between 20° N and 25° S). Hundreds of millions of people are at risk of infection in more than 70 nations, mostly in developing countries. The second species has been reported only in Ecuador and Peru. Males and non-fertilized females of Tunga are haematophagous ectoparasites; pregnant females penetrate the skin where, following dilatation of the abdomen, they increase enormously in size (neosomy) and cause inflammatory and ulcerative processes of varying severity. The importance of Tunga infection in humans concerns its frequent localization in the foot, which sometimes causes very serious difficulty in walking, thereby reducing the subject's ability to work and necessitating medical and surgical intervention. Tungiasis in domestic animals can be responsible for economic losses resulting from flea-induced lesions and secondary infections. Because tungiasis represents a serious problem for tropical public health and because of the recent description of a new species (Tunga trimamillata), it seems appropriate to review current knowledge of the morphology, molecular taxonomy, epidemiology, pathology, treatment and control of sand fleas of the genus Tunga. [source] Covert attention allows for continuous control of brain,computer interfacesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2010Ali Bahramisharif Abstract While brain-computer interfaces (BCIs) can be used for controlling external devices, they also hold the promise of providing a new tool for studying the working brain. In this study we investigated whether modulations of brain activity by changes in covert attention can be used as a continuous control signal for BCI. Covert attention is the act of mentally focusing on a peripheral sensory stimulus without changing gaze direction. The ongoing brain activity was recorded using magnetoencephalography in subjects as they covertly attended to a moving cue while maintaining fixation. Based on posterior alpha power alone, the direction to which subjects were attending could be recovered using circular regression. Results show that the angle of attention could be predicted with a mean absolute deviation of 51° in our best subject. Averaged over subjects, the mean deviation was ,70°. In terms of information transfer rate, the optimal data length used for recovering the direction of attention was found to be 1700 ms; this resulted in a mean absolute deviation of 60° for the best subject. The results were obtained without any subject-specific feature selection and did not require prior subject training. Our findings demonstrate that modulations of posterior alpha activity due to the direction of covert attention has potential as a control signal for continuous control in a BCI setting. Our approach will have several applications, including a brain-controlled computer mouse and improved methods for neuro-feedback that allow direct training of subjects' ability to modulate posterior alpha activity. [source] Involvement of the human frontal eye field and multiple parietal areas in covert visual selection during conjunction searchEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2000Tobias Donner Abstract Searching for a target object in a cluttered visual scene requires active visual attention if the target differs from distractors not by elementary visual features but rather by a feature conjunction. We used functional magnetic resonance imaging (fMRI) in human subjects to investigate the functional neuroanatomy of attentional mechanisms employed during conjunction search. In the experimental condition, subjects searched for a target defined by a conjunction of colour and orientation. In the baseline condition, subjects searched for a uniquely coloured target, regardless of its orientation. Eye movement recordings outside the scanner verified subjects' ability to maintain fixation during search. Reaction times indicated that the experimental condition was attentionally more demanding than the baseline condition. Differential activations between conditions were therefore ascribed to top-down modulation of neural activity. The frontal eye field, the ventral precentral sulcus and the following posterior parietal regions were consistently activated: (i) the postcentral sulcus; (ii) the posterior; and (iii) the anterior part of the intraparietal sulcus; and (iv) the junction of the intraparietal with the transverse occipital sulcus. Parietal regions were spatially distinct and displayed differential amplitudes of signal increase with a maximal amplitude in the posterior intraparietal sulcus. Less consistent activation was found in the lateral fusiform gyrus. These results suggest an involvement of the human frontal eye field in covert visual selection of potential targets during search. These results also provide evidence for a subdivision of posterior parietal cortex in multiple areas participating in covert visual selection, with a major contribution of the posterior intraparietal sulcus. [source] Learner Accuracy and Learner Performance: The Quest for a LinkFOREIGN LANGUAGE ANNALS, Issue 2 2000Janet M. Renou Specifically, we examined learner performance in carrying out three steps of a written and oral grammatically judgment test. First, subjects' ability to identify and correct an error, and to provide the rule, which the correction entailed, was examined according to group membership (communicative or grammar), types of errors, and mode of presentation. In a second phase of the analysis, judgment ability was compared with specific aspects of L2 proficiency. Results show significant differences between the groups in their ability to provide the rule that the correction entailed. Furthermore, significant differences in judgment ability were found depending on whether the item was presented in the written or oral mode. Generally, little difference was found in levels of L2 proficiency between subjects who could correct the error and provide the rule in comparison with those who were only able to correct the error. [source] | |||||||||||||