69 resultados para Stimulus Duration

em Deakin Research Online - Australia


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This paper reports a single case of ipsilesional left neglect dyslexia and interprets it according to the three-level model of visual word recognition proposed by Caramazza and Hillis (1990). The three levels reflect a progression from the physical stimulus to an abstract representation of a word. RR was not impaired at the first, retinocentric, level, which represents the individual features of letters within a word according to the location of the word in the visual field: She made the same number of errors to words presented in her left visual field as in her right visual field. A deficit at this level should also mean the patient neglects all stimuli. This did not occur with RR: She did not neglect when naming the items in rows of objects and rows of geometric symbols. In addition, although she displayed significant neglect dyslexia when making visual matching judgements on pairs of words and nonwords, she did not do so to pairs of nonsense letter shapes, shapes which display the same level of visual complexity as letters in words. RR was not impaired at the third, graphemic, level, which represents the ordinal positions of letters within a word: She continued to neglect the leftmost (spatial) letter of words presented in mirror-reversed orientation and she did not neglect in oral spelling. By elimination, these results suggest RR's deficit affects a spatial reference frame where the representational space is bounded by the stimulus: A stimulus-centred level of representation. We define five characteristics of a stimulus-centred deficit, as manifest in RR. First, it is not the case that neglect dyslexia occurs because the remaining letters in a string attract or capture attention away from the leftmost letter(s). Second, the deficit is continuous across the letter string. Third, perceptually significant features, such as spaces, define potential words. Fourth, the whole, rather than part, of a letter is neglected. Fifth, category information is preserved. It is concluded that the Caramazza-Hillis model accounts well for RR's data, although we conclude that neglect dyslexia can be present when a more general visuospatial neglect is absent.

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This study used quantitative and qualitative techniques to examine the role of health, age, and duration of illness among people with multiple sclerosis (MS) in their economic well-being. Participants were 113 adults (31 males and 82 females) with MS who lived in urban and rural regions of Australia. The results demonstrated that health and age had a significant impact on both the economic well-being and psychological adjustment of people who contract this disorder. Different health variables predicted different aspects of economic well-being. Fatigue was the major health variable that predicted costs of MS and economic pressure, with age also predicting economic pressure, whereas income levels were predicted by cognitive confusion and mobility problems. Duration of illness, gender, and urban/rural location were not significant predictors of the economic variables. These results demonstrate the importance of obtaining multiple measures of economic well-being, as well as a broad range of health-related measures, in determining the impact of MS on the economic well-being of people with this disorder.

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Sixteen young (25±2.6 years) and 16 older individuals (69±4.4 years) walked normally then terminated walking rapidly. A visual stopping stimulus was presented 10 ms following ground contact (short delay) and in another condition, at 450 ms prior to toe-off (long delay). Stimulus probability was either high (80% of trials) or low (10%). The younger group stopped faster (463 vs. 574 ms) despite also walking faster (1.29 vs. 1.17 m s−1). Longer delay decreased one-step responses but older participants used significantly more (slower) two-step stopping, which increased stopping time and distance. The additional step may have been pre-planned to maintain medial–lateral stability.

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The current study investigated the association between the severity and duration of physical disability and body esteem. A total of 748 participants (367 males, 381 females) who had a physical disability and 448 participants (171 males, 277 females) who were able-bodied participated in the study. The results demonstrated that people with more severe physical disability experienced lower levels of body esteem than people with milder physical disabilities and able-bodied people. The duration of physical disability was not related to levels of body esteem. Except for the face, people with physical disabilities devalued all aspects of their body more than able-bodied people. For males with physical disability, the unique predictors of high body esteem were decreased need for assistance, higher self-esteem, lower depression and higher sexual esteem; for females with physical disability, the unique predictors were higher self-esteem and higher sexual esteem. Overall, the study suggested that people with physical disability, particularly those with severe disabilities, may be particularly vulnerable to problems associated with their body esteem.

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There is a lack of research and literature concerned with services which are produced and delivered over substantial, sustained time periods. The growing Leisure Air Travel industry has a major component of extended–duration product (long-haul flights). In the existing literature, there is little or no distinction made between leisure and business travellers regarding their motivation and expectations, the duration of the service encounters and the travellers’ evaluation of the service. The authors propose that leisure and business travellers have distinct and differing motives for travelling which affect their service evaluation. The individual consumers’ characteristics, combined with industry conditions and the complex product component, mean that measuring consumer satisfaction, with leisure air travel, in a useful way is problematic. The authors suggest that a major part of the complexity of the product is that leisure air travel is a high-involvement, high-affect, extended service. In June 2000 and February 2001, exploratory research in the form of focus groups conducted using a total of 110 passengers from a United Kingdom leisure airline, revealed several important criteria used by consumers when evaluating service provision. The criteria are grouped into six factors: Hygiene, Service/Empathy, Psychological, Temporal, Personal Characteristics, and Situation Specifics. A new model for examining the relationships between the factors, the
airline and satisfaction evaluation is proposed.

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The duration of periods spent ashore versus foraging at sea, diving behaviour, and diet of lactating female Antarctic (Arctocephalus gazella, AFS) and subantarctic (A. tropicalis, SFS) fur seals were compared at Iles Crozet, where both species coexist. The large disparity in lactation duration (SFS: 10 months, AFS: 4 months), even under local sympatry, has led to the expectation that AFS should exhibit higher foraging effort or efficiency per unit time than SFS to allow them to wean their pups in a shorter period of time. Previous evidence, however, has not supported these expectations. In this study, the distribution of foraging trip durations revealed two types of trips: overnight (OFT, <1 day) and long (LFT, >1 day), in common with other results from Macquarie Island. However, diving behaviour differed significantly between foraging trip types, with greater diving effort in OFTs than in LFTs, and diving behaviour differed between fur seal species. OFTs were more frequent in SFS (48%) than in AFS (28%). SFS performed longer LFTs and maternal attendances than AFS, but spent a smaller proportion of their foraging cycle at sea (66.2 vs. 77.5%, respectively). SFS dove deeper and for longer periods than AFS, in both OFTs and LFTs, although indices of diving effort were similar between species. Diel variation in diving behaviour was lower among SFS, which foraged at greater depths during most of the night time available than AFS. The diving behaviour of AFS suggests they followed the nychthemeral migration of their prey more closely. Concomitant with the differences in diving behaviour, AFS and SFS fed on the same prey species, but in different proportions of three myctophid fish (Gymnoscopelus fraseri, G. piabilis, and G. nicholsi) that represented most of their diet. The estimated size of the most important fish consumed did not vary significantly between fur seal species, suggesting that the difference in dive depth was mostly a result of changes in the relative abundance of these myctophids. The energy content of these fish at Iles Crozet may thus influence the amount and quality of milk delivered to pups of each fur seal species. These results contrast with those found at other sites where both species coexist, and revealed a scale of variation in foraging behaviour which did not affect their effort while at sea, but that may be a major determinant of foraging efficiency and, consequently, maternal investment.

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Rapid processing deficits have been the subject of much debate in the literature on specific language impairment (SLI). Hari and Renvall (2001) [Hari, R. & Renvall, H. (2001). Impaired processing of rapid stimulus sequences in dyslexia. Trends in cognitive sciences, 5, 525–532.] proposed that the source of this deficit can be attributed to sluggish attentional shifting abilities. That is, more time is required to shift attention between stimuli. To test this claim, 26 adolescents with SLI (divided into two subgroups to control for differences in non-verbal intelligence) and 14 controls were presented with a rapid serial visual presentation task. In this task participants were asked to detect two visual targets presented serially with distracter items with varying inter-target intervals (i.e., time difference between targets). This task was designed to elicit an attentional blink (AB). The AB describes the phenomenon whereby non-impaired individuals are less likely to report the second of two targets presented within 200–500 ms of each other. After controlling for group differences in non-verbal intelligence, the SLI group was found to be significantly less accurate than the control group at successfully reporting the second target at inter-target intervals of 100, 200, 300, 400 and 800 ms. The results were interpreted to suggest that adolescents with language impairments have an AB which differs from non-impaired individuals in both magnitude and duration.

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Objective: This study examined the optimal stimulation duration of transcutaneous electrical nerve stimulation (TENS) for relieving osteoarthritic knee pain and the duration (as measured by half-life) of post-stimulation analgesia. Subjects: Thirty-eight patients received either: (i) 20 minutes (TENS20); (ii) 40 minutes (TENS40); (iii) 60 minutes (TENS60) of TENS; or (iv) 60 minutes of placebo TENS (TENSPL) 5 days a week for 2 weeks. Methods: A visual analogue scale recorded the magnitude and pain relief period for up to 10 hours after stimulation. Results: By Day10, a significantly greater cumulative reduction in the visual analogue scale scores was found in the TENS40 (83.40%) and TENS60 (68.37%) groups than in the TENS20 (54.59%) and TENSPL (6.14%) groups (p 3 0.000), such a group difference was maintained in the 2-week followup session (p 3 0.000). In terms of the duration of post-stimulation analgesia period, the duration for the TENS40 (256 minutes) and TENS60 (258 minutes) groups was more prolonged than in the other 2 groups (TENS20 = 168 minutes, TENSPL = 35 minutes) by Day10 (p 3 0.000). However, the TENS40 group produced the longest pain relief period by the follow-up session. Conclusion: 40 minutes is the optimal treatment duration of TENS, in terms of both the magnitude (VAS scores) of pain reduction and the duration of post-stimulation analgesia for knee osetoarthritis.

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A finding of the Australian Initial Public Offerings (IPOs) literature is that the time from prospectus registration to listing is related to the level of informed demand. This makes the understanding of time to listing an important matter. This study analyses the time to listing for 834 IPOs in Australia over the period 1994 to 2004. The study finds that a shorter time to listing is associated with higher issue prices, and the use of an underwriter or Big 5 independent accountant. In contrast, IPOs offering share options take longer to list. The significant role of variables associated with the degree of certainty about a listing is consistent with informed demand hypotheses about the time to listing.

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Shamanism has remained an integral part of indigenous healing rituals since ancient times and is currently attracting interest as a complementary therapeutic technique in psychology. Recently, shamanic-like techniques have been used to facilitate changes in the phenomenology of nonshamans. However, such research has largely been delimited to a single shamanic-like technique (i.e., drumming), and the role of personality traits with regards to receptivity to this technique has been neglected. The purpose of the present study was to investigate experimentally the effect of different shamanic-like techniques and the cognitive-perceptual factor of the schizotypy construct on phenomenology. One hundred and four non-shamans were randomly assigned to one of three conditions: Drumming, Ganzfeld, or Sitting Quietly with Eyes Open. Participants' phenomenology was assessed using the Phenomenology of Consciousness Inventory, Phenomenology associated with shamanic-like techniques appeared to be statistically significantly different from phenomenology associated with sitting quietly with eyes open. Furthermore, high cognitive-perceptual participants reported significant alterations in phenomenology compared to their low cognitive-perceptual counterparts. Methodological shortcomings of the present study are discussed and suggestions for future research are advanced.

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Objectives: This cross-sectional study was designed to evaluate whether the duration of erectile dysfunction (ED) influenced treatment seeking and satisfaction with treatment using PDE5 inhibitors.
Methods: Participants were 409 men with ED who were primarily recruited over the internet via men's health web sites. Participants completed a questionnaire to assess the duration and perceived severity of ED, information and help-seeking behaviors for ED, and treatment usage and satisfaction with PDE5 inhibitor medication.
Results: The results demonstrated that men with ED of longer duration were more likely to have discussed their ED with their partner and doctor and to have sought information and treatment for their ED problem. No differences were found in reported satisfaction with ED medication usage or expected future medication use across the varying levels of ED duration, once variance attributable to age was accounted for.
Conclusions: These results suggest that men are more likely to accept that they have ED and seek treatment for their ED with increasing duration of the condition, although these men are not more satisfied with PDE5 inhibitors as a treatment option.

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Research over the last decade has shown that auditorily cuing the location of visual targets reduces the time taken to locate and identify targets for both free-field and virtually presented sounds. The first study conducted for this thesis confirmed these findings over an extensive region of free-field space. However, the number of sound locations that are measured and stored in the data library of most 3-D audio spatial systems is limited, so that there is often a discrepancy in position between the cued and physical location of the target. Sampling limitations in the systems also produce temporal delays in which the stored data can be conveyed to operators. To investigate the effects of spatial and temporal disparities in audio cuing of visual search, and to provide evidence to alleviate concerns that psychological research lags behind the capabilities to design and implement synthetic interfaces, experiments were conducted to examine (a) the magnitude of spatial separation, and (b) the duration of temporal delay that intervened between auditory spatial cues and visual targets to alter response times to locate targets and discriminate their shape, relative to when the stimuli were spatially aligned, and temporally synchronised, respectively. Participants listened to free-field sound localisation cues that were presented with a single, highly visible target that could appear anywhere across 360° of azimuthal space on the vertical mid-line (spatial separation), or extended to 45° above and below the vertical mid-line (temporal delay). A vertical or horizontal spatial separation of 40° between the stimuli significantly increased response times, while separations of 30° or less did not reach significance. Response times were slowed at most target locations when auditory cues occurred 770 msecs prior to the appearance of targets, but not with similar durations of temporal delay (i.e., 440 msecs or less). When sounds followed the appearance of targets, the stimulus onset asynchrony that affected response times was dependent on target location, and ranged from 440 msecs at higher elevations and rearward of participants, to 1,100 msecs on the vertical mid-line. If targets appeared in the frontal field of view, no delay of acoustical stimulation affected performance. Finally, when conditions of spatial separation and temporal delay were combined, visual search times were degraded with a shorter stimulus onset asynchrony than when only the temporal relationship between the stimuli was varied, but responses to spatial separation were unaffected. The implications of the results for the development of synthetic audio spatial systems to aid visual search tasks was discussed.