22 research outputs found
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A texture-processing model of the 'visual sense of number'
It has been suggested that numerosity is an elementary quality of perception, similar to colour. If so (and despite considerable investigation), its mechanism remains unknown. Here, we show that observers require on average a massive difference of approximately 40% to detect a change in the number of objects that vary irrelevantly in blur, contrast and spatial separation, and that some naive observers require even more than this. We suggest that relative numerosity is a type of texture discrimination and that a simple model computing the contrast energy at fine spatial scales in the image can perform at least as well as human observers. Like some human observers, this mechanism finds it harder to discriminate relative numerosity in two patterns with different degrees of blur, but it still outpaces the human. We propose energy discrimination as a benchmark model against which more complex models and new data can be tested
An inability to exclude visual noise in migraine
- Purpose: People with migraine are relatively poor at judging the direction of motion of coherently moving signal dots when interspersed with noise dots drifting in random directions, a task known as motion coherence. Although this has been taken as evidence of impoverished global pooling of motion signals, it could also arise from unreliable coding of local direction (of each dot), or an inability to segment signal from noise (noise-exclusion). The aim of this study was to determine how these putative limits contribute to impoverished motion processing in migraine.
- Methods: Twenty-two participants with migraine (mean age, 34.7 ± 8.3 years; 16 female) and 22 age- and sex-matched controls (mean age, 34.4 ± 6.2 years) performed a motion-coherence task and a motion-equivalent noise task, the latter quantifying local and global limits on motion processing. In addition, participants were tested on analogous equivalent noise paradigms involving judgments of orientation and size, so that the specificity of any findings (to visual dimension) could be ascertained.
- Results: Participants with migraine exhibited higher motion-coherence thresholds than controls (P = 0.01, independent t-test). However, this difference could not be attributed to deficits in either local or global processing since they performed normally on all equivalent noise tasks (P > 0.05, multivariate ANOVA).
- Conclusions: These findings indicate that motion perception in the participants with migraine was limited by an inability to exclude visual noise. We suggest that this is a defining characteristic of visual dysfunction in migraine, a theory that has the potential to integrate a wide range of findings in the literature
Guidelines for postoperative care in gynecologic/oncology surgery: Enhanced Recovery After Surgery (ERASÂź) Society recommendations - Part II.
This article is freely available via Open Access. Click on the 'Additional Link' above to access the full-text via the publisher's site.Published (Open Access
Detection of bilateral symmetry using spatial filters
When bilaterally symmetric images are spatially filtered and thresholded, a subset of the resultant 'blobs' cluster around the axis of symmetry. Consequently, a quantitative measure of blob alignment can be used to code the degree of symmetry and to locate the axis of symmetry. Four alternative models were tested to examine which components of this scheme might be involved in human detection of symmetry. Two used a blob-alignment measure, operating on the output of either isotropic or oriented filters. The other two used similar filtering schemes, but measured symmetry by calculating the correlation of one half of the pattern with a reflection of the other. Simulations compared the effect of spatial jitter, proportion of matched to unmatched dots and width or location of embedded symmetrical regions, on models' detection of symmetry. Only the performance of the oriented filter + blob-alignment model was consistent with human performance in all conditions. It is concluded that the degree of feature co-alignment in the output of oriented filters is the cue used by human vision to perform these tasks. The broader computational role that feature alignment detection could play in early vision is discussed, particularly for object detection and image segmentation. In this framework, symmetry is a consequence of a more general-purpose grouping scheme
"Man kan ju inte pysa allt". Fem svensklÀrares erfarenheter av bedömning och betygssÀttning av gymnasieelever med hörselnedsÀttningar
Syfte: Syftet med studien Àr att undersöka hur gymnasielÀrare i Svenska 1 arbetar med betygssÀttning och bedömning av elever med hörselnedsÀttningar, bÄde i vanliga skolor sÄvÀl som i hörsel-/specialklasser. Undersökningen tar Àven upp undantagsbestÀmmelsen, den sÄ kallade pysparagrafen, samt belyser hur denna tillÀmpas och/eller om lÀrare istÀllet anpassar undervisningen under kursens gÄng. Studien lyfter Àven skillnader och likheter mellan skolformerna avseende bedömning, betygssÀttning och tillÀmpning av pysparagrafen.
Teori: Studien bottnar i det sociokulturella perspektivet dÀr lÀrande sker i sociala sammanhang tillsammans med andra. Men dÄ fokus Àr riktat mot specialpedagogiska frÄgor om hur man bedömer och betygssÀtter elever med funktionsnedsÀttningar blir delaktighet och kommunikation av stor betydelse för hur eleverna ska lyckas i skolan. Det kommunikativa relationsinriktade perspektivet, KoRP, har dÀrmed valts som studiens teoretiska ram.
Metod: Undersökningen har genomförts med hjÀlp av kvalitativa intervjuer av halvstrukturerad art. Urvalet bestÄr av fem gymnasielÀrare som alla nÄgon gÄng har betygssatt och undervisat elever med hörselnedsÀttningar i kursen Svenska 1 alternativt Svenska A. I gruppen finns representanter bÄde frÄn praktiskt och teoretiskt program samt frÄn vanliga gymnasieskolan, hörselklass och specialklasser. Intervjuerna genomfördes med hjÀlp av en intervjuguide vilken utvecklades eller frÄngicks vid behov beroende av hur samtalen fortlöpte. Tolkning och analys har gjorts med ad-hoc metod dÀr mönster och kategorier skapats utifrÄn studiens syfte och frÄgestÀllningar. KoRP-perspektivet har anvÀnts som analytiskt verktyg för att förstÄ hur kommunikation, relationer samt delaktighet pÄverkar elever med hörselnedsÀttningar att lyckas i sitt lÀrande.
Resultat: I studien framkom det att de lĂ€rare som hade stor erfarenhet av att undervisa elever med funktionsnedsĂ€ttningar, till exempel hörselnedsĂ€ttningar, var mer bekanta eller till och med visade sig vara vĂ€l förtrogna med undantagsbestĂ€mmelsen. De lĂ€rare som hade mindre erfarenhet av denna elevkategori och i större omfattning undervisade vanliga klasser pĂ„ teoretiska eller praktiska program kĂ€nde till undantagsparagrafen mer flyktigt. NĂ„got som Ă„terkom i intervjuerna var att ju bĂ€ttre kommunikationen Ă€r mellan eleven och lĂ€raren, desto lĂ€ttare blir det att anpassa undervisningen för att möta elevens behov pĂ„ bĂ€sta möjliga sĂ€tt. Graden av hörselnedsĂ€ttning visade sig vara en avgörande faktor för huruvida undantagsbestĂ€mmelsen eller anpassningar av undervisningen behövdes eller ej. Samtliga lĂ€rare i undersökningen tillĂ€mpade eller strĂ€vade efter att tillĂ€mpa formativ bedömning. Det framkom Ă€ven att alla fem lĂ€rarna ansĂ„g att specialskolor behövs som komplement till en inkluderad skola âför allaâ