Retinotopic and lateralized processing of spatial frequencies in human visual cortex during scene categorization.

International audienceUsing large natural scenes filtered in spatial frequencies, we aimed to demonstrate that spatial frequency processing could not only be retinotopically mapped but could also be lateralized in both hemispheres. For this purpose, participants performed a categorization task using large black and white photographs of natural scenes (indoors vs. outdoors, with a visual angle of 24° × 18°) filtered in low spatial frequencies (LSF), high spatial frequencies (HSF), and nonfiltered scenes, in block-designed fMRI recording sessions. At the group level, the comparison between the spatial frequency content of scenes revealed first that, compared with HSF, LSF scene categorization elicited activation in the anterior half of the calcarine fissures linked to the peripheral visual field, whereas, compared with LSF, HSF scene categorization elicited activation in the posterior part of the occipital lobes, which are linked to the fovea, according to the retinotopic property of visual areas. At the individual level, functional activations projected on retinotopic maps revealed that LSF processing was mapped in the anterior part of V1, whereas HSF processing was mapped in the posterior and ventral part of V2, V3, and V4. Moreover, at the group level, direct interhemispheric comparisons performed on the same fMRI data highlighted a right-sided occipito-temporal predominance for LSF processing and a left-sided temporal cortex predominance for HSF processing, in accordance with hemispheric specialization theories. By using suitable method of analysis on the same data, our results enabled us to demonstrate for the first time that spatial frequencies processing is mapped retinotopically and lateralized in human occipital cortex

Distribution, abundance and biological studies of economically important fishes in the South China Sea, Area II: Sarawak, Sabah and Brunei Darussalam waters

The studies were carried out between 9th July and 3rd August 1996 (3rd cruise) and 30th April and 30th May, 1997 (4th cruise) in the Exclusive Economic Zone of Sarawak and the western part of Sabah. The species distribution, abundance, composition and length-weight relationships of some commercially important fish were investigated and compared for both cruises. The results indicate that the overall catch rate ranged from 3.5 to 194 kg/hr and averaged at 55.9 kg/hr during the 3rd cruise. For the 4th cruise, it ranged from 10.9 to 90.5 kg/hr and averaged at 50.2 kg/hr. During the 3rd cruise, 46.9% of the catch were dominated by demersal fish followed by 41.6% trash fish, 7.8% pelagic fish and 3.1% cephalopod. Priacanthidae was the most dominant family, which made up of 14.1% of the catch followed by Nemipteridae (10.8%), Carangidae (5.0%), Lutjanidae (3.7%) and Mullidae (2.1%). The ten most dominant species found during the 3rd cruise were 1. Priacanthus macracanthus (13.2%), 2. Nemipterus bathybius (3.3%), 3. Abalistes stellaris (2.8%), 4. Arius spp.(2.5%), 5. N. nematophorus (2.2%), 6. Gymnocranius griseus (1.9%), 7. N. marginatus (1.7%), 8. Sepia spp. (1.7%), 9. Decapterus spp. (1.6%) and 10. Carcharhinus spp (1.3%). During the 4th cruise, the family Nemipteridae (12.7%) formed the most dominant fish family followed by Carangidae (8.7%), Mullidae (7.1%), Lutjanidae (4.9%) and Priacanthidae (2.2%). The ten most dominant species were: 1. Loligo spp. (5.7%), 2. Nemipterus bathybius (4.2%), 3. Abalistes stellaris (4.0%), 4. Upeneus moluccensi (3.8%), 5. Nemipterus nemurus (3.8%), 6. Gymnocranius griseus (3.2%), 7. Carangoides malabaricus (3.2%), 8. Plectorhynchus pictus (3.1%), 9. Upeneus bensasi (2.4%) and 10. Arius spp. (1.8%). The morphometric study shows that the population of fish are normally distributed

Checklist of gastropods from the exclusive economic zone (EEZ), Sarawak, Malaysia

This study provides the first marine gastropod checklist from the Sarawak Exclusive Economic Zone (EEZ). Gastropod samples were collected from selected stations in the Sarawak EEZ using an otter trawl net with a stretched mesh size of 38 mm at the cod end. The trawling operations were conducted more than 12 nautical miles from the coast, and the area was divided into three depth strata: I) 20–50 m, II) 50–100 m and III) 100–200 m. A total of 23 gastropod species were identified during the two-month sampling period from 16 August until 6 October 2015, representing 8 superfamilies, 15 families and 20 genera. Superfamily Tonnoidea was represented by 7 species, followed by Muricoidea (5 species), Cypraeoidea (4 species), and Buccinoidea and Conoidea (both with 2 species). Other superfamilies were represented by a single species. Only 3 species were obtained in 2 depth strata, namely Melo melo, Murex aduncospinosus and Tonna galea. In addition, 9, 13 and 4 species of gastropods were found in strata I, II and III, respectively. The information on gastropod distributions at different depth strata in the Sarawak EEZ could be useful in updating the Malaysian species diversity databas

El tema / La marca

Quienes ejercemos la docencia debemos brindarles a nuestros alumnos herramientas conceptuales y metodológicas que les permitan desarrollarse en escenarios futuros, que aún no conocemos y que tendrán profundas diferencias con los anteriores y actuales. Por ello, necesitamos fomentar el pensamiento complejo (Morin, 1990), considerando la multiplicidad de causas y efectos que se ponen en juego en los procesos de identificación, de comunicación y de consumo. El texto discute el concepto y los usos de "marca".Facultad de Arte

Investigating the effectiveness of spatial frequencies to the left and right of central vision during reading:Evidence from reading times and eye movements

Printed words are complex visual stimuli containing a range of different spatial frequencies, and several studies have suggested that various spatial frequencies are effective for skilled adult reading. But while it is well known that the area of text from which information is acquired during reading extends to the left and right of each fixation, the effectiveness of spatial frequencies falling each side of fixation has yet to be determined. To investigate this issue, we used a spatial frequency adaptation of the gaze-contingent moving-window paradigm in which sentences were shown to skilled adult readers either entirely as normal or filtered to contain only low, medium, or high spatial frequencies except for a window of normal text around each point of fixation. Windows replaced filtered text either symmetrically 1 character to the left and right of each fixated character, or asymmetrically, 1 character to the left and 7 or 13 to the right, or 1 character to the right and 7 or 13 to the left. Reading times and eye-movement measures showed that reading performance for sentences presented entirely as normal generally changed very little with filtered displays when windows extended to the right but was often disrupted when windows extended to the left. However, asymmetrical windows affected performance on both sides of fixation. Indeed, increasing the leftward extent of windows from 7 to 13 characters produced decreases in both reading times and fixation durations, suggesting that reading was influenced by the spatial frequency content of leftward areas of text some considerable distance from fixation. Overall, the findings show that while a range of different spatial frequencies can be used by skilled adult readers, the effectiveness of spatial frequencies differs for text on each side of central vision, and may reflect different roles played by these two areas of text during reading

Redesigning the Passenger Experience in the Context of Commercial Aviation: Door to Door

When addressing the topic of travel, a series of mixed emotions can rise up within us. Stemming from our experience from previous trips, we may choose to see the entire trip as a positive or negative based upon a single element: air travel. I am to improve the overall perception of air travel by redesigning the passenger experience in the context of commercial aviation: door to door. What this means is that I plan to investigate and improve the expedience and convenience for the passenger when navigating to, through, and from the realm of travel via means of passenger aircraft. Rather than just focusing on improving the airport, I want to encapsulate the entire experience; from the second you leave your home to the moment you arrive at your destination. This stretches across a broad array of factors to consider, such as luggage transportation, accommodation/reservation management, as well as the atmosphere for the passenger in flight, just to name a few. As a result, I aim to create a new network of systems that is integrated cohesively to one another to focus not on the amount of money to be made, but rather on the betterment of the entire air travel passenger experience

How Can I Leave You

https://digitalcommons.library.umaine.edu/mmb-vp-copyright/4755/thumbnail.jp