Sequential memory-guided saccades and target selection: a neural model of the frontal eye fields

AbstractWe present a neural model of the frontal eye fields. It consists of several retinotopic arrays of neuron-like units that are recurrently connected. The network is trained to make memory-guided saccades to sequentially flashed targets that appear at arbitrary locations. This task is interesting because the large number of possible sequences does not permit a pre-learned response. Instead locations and their priority must be maintained in active working memory. The network learns to perform the task. Surprisingly, after training it can also select targets in visual search tasks. When targets are shown in parallel it chooses them according to their salience. Its search behavior is comparable to that of humans. It exhibits saccadic averaging, increased reaction times with more distractors, latency vs accuracy trade-offs, and inhibition of return. Analysis of the network shows that it operates like a queue, storing the potential targets in sequence for later execution. A small number of unit types are sufficient to encode this information, but the manner of coding is non-obvious. Units respond to multiple targets similar to quasi-visual cells recently studied [Exp. Brain Res. 130 (2000) 433]. Predictions are made that can be experimentally tested

Effect of detergent and sawdust addition on hydrocarbon reduction and growth of Abelmoschus esculentus L (Okra) in a petroleum-contaminated soil

A study to investigate the effect of sawdust and detergent on hydrocarbon reduction and the growth of okra (Abelmoschus esculentus L.) in petroleum polluted soil was carried out. The study was conducted at the Centre for Ecological Studies, University of Port Harcourt. Bonny light crude (300 ml) was used to pollute 10 kg soil. Detergent (20 g), sawdust (200 g) and sawdust: detergent (200 g: 20 g) were used as the amendment materials alongside a control (pollution but un-remediated) arranged in a completely randomized design of 12 replications. After 30 days post-amendment, 3 seeds of okra (var: V35-45 days) were grown in each treatment pot for 6 weeks. Soil Total Hydrocarbon Content (THC) and okra growth performance (shoot length, leaf number, root length, total fresh weight, dry weight, leaf area and leaf area ratio) were analyzed. Results showed significant (p=0.05) reductions in THC of 44.23%, 26.5%, 70.80% and 10.79%, in detergent (20 g), sawdust (200 g), sawdust (200 g) + detergent (20 g) and control, respectively. Improved growth performances of okra were observed in the amended soil as compared to the control. Okra growth performance was in the order of: 200 g sawdust + 20 g detergent combination > 200 g sawdust > 20 g detergent. This implies that these two materials are good bio-stimulation materials especially when used in combined form for THC reduction and growth of okra.Keywords: Abelmoschus esculentus L., contamination, crude oil, sawdust, total hydrocarbon conten

Do New Media Make the Practice of Journalism More or Less a Profession?

This review examines the role of new media in the ongoing debate about journalism being a profession or not. The paper gives an overview of professionalism, contending issues in the journalistic profession debate, the new media, and the influence of new media in the debate. Drawing from a huge body of literature on new media usage, journalism, professionalism and practical examples, the paper contends that the new media contribute for and against journalistic professionalism. In terms of contributing for journalistic professionalism, it is observed among other things that the new media provide tools that improve journalism practices, making journalism significantly socially responsible to society. This is a core criterion of professionalism. In terms of contributing against journalistic professionalism, the paper contends inter alia that the extreme freedom associated with the new media render many people, without any formal journalistic training, journalists. With this, very many cases of unethical practices are the case. Similarly, the nature of new media makes it extremely difficult to regulate its usage. All these are in opposition to a number of general criteria of professionalism. With these overwhelming evidences, the position of the paper is that, at present, the new media work against journalistic professionalism than for it. Key words: Debate, journalism, new media, non-profession, profession.

Spatial Attention Modulates Center-Surround Interactions in Macaque Visual Area V4

SummaryIn natural viewing, a visual stimulus that is the target of attention is generally surrounded by many irrelevant distracters. Stimuli falling in the receptive field surround can influence the neuronal response evoked by a stimulus appearing within the classical receptive field. Such modulation by task-irrelevant distracters may degrade the target-related neuronal signal. We therefore examined whether directing attention to a target stimulus can reduce the influence of task-irrelevant distracters on neuronal response. We find that in area V4 attention to a stimulus within a neuron's receptive field filters out a large fraction of the suppression induced by distracters appearing in the surround. When attention is instead directed to the surround stimulus, suppression is increased, thereby filtering out part of the neuronal response to the irrelevant distracter positioned within the receptive field. These findings demonstrate that attention modulates the neural mechanisms that give rise to center-surround interactions

Attentional selection of superimposed surfaces cannot be explained by modulation of the gain of color channels

AbstractWhen two differently colored, superimposed patterns of dots rotate in opposite directions, this yields the percept of two superimposed transparent surfaces. If observers are cued to attend to one set of dots, they are impaired in making judgments about the other set. Since the two sets of dots are overlapping, the cueing effect cannot be explained by spatial attention. This has led to the interpretation that the impairment reflects surface-based attentional selection. However, recent single-unit recording studies in monkeys have found that attention can modulate the gain of neurons tuned for features such as color. Thus, rather than reflecting the selection of a surface, the behavioral effects might simply reflect a reduction in the gain of color channels selective for the color of the uncued set of dots (feature-based attention), as if viewing the surfaces through a colored filter. If so, then the impairment should be eliminated when the two surfaces are made the same color. Instead, we find that the impairment persists with no reduction in strength. Our findings thus rule out the color gain explanation

Geographic Information System for Upscaling the Seaweed Industry Operation In Two Areas in Mindanao, Southern Philippines

This study used the geographic information system (GIS) in mapping cultured seaweed (Kappaphycus and Eucheuma) areas as production support system for sustainable farming and upscaling of seaweed industry operation. However, the current information on the aerial extent and spatial distribution of seaweeds farms in the Philippines has limited accuracy and reliability. To address this, the ArcGIS tool and spatial method was used in compiling bio-physical and socio-economic data, including the extent of seaweed production areas, the culture techniques and systems, and other relevant information on the various farming sites in the Davao Region and major production areas in Tawi-Tawi Province of Mindanao, Southern Philippines. The results show that major source of seaweeds in Davao Region comes from Davao del Sur while for Tawi-Tawi, the bulk of production is from Sitangkai. For seaweed extent, Davao Region reaches a total of 408.59 ha while Tawi-Tawi covers 47,802.18 ha. In terms of the salinity level, Davao Region ranges from 27 to 32 ppt and Tawi-Tawi from 31 to 32 ppt. Temperature level ranges from 26 to 27 °C in Davao Region and 27– 30 °C in Tawi-Tawi. As to the socio-economic dimension, the most common farming method applied in both areas is the multiple floating long-line; however, several culture systems were recorded such as basket, monoline, and fix-off bottom methods. The product flow and value chain mapping suggest the absence of consolidators in some areas and the lack of coordination and complementation among seaweed industry enablers, which may have contributed setbacks to the industry on top of the prevailing problems on diseases and environment-related issues. The results of this study may assist decision making for seaweed farming operations and eventually upscale the seaweed industry in Mindanao and the whole country

Diet and Selection of Major Prey Species by Lake Michigan Salmonines, 1973–1982

To elucidate prey preferences, we quantified stomach contents of 1,231 salmonines collected from inshore (21 m or shallower) southeastern Lake Michigan during 1973–1982. Predators ate 12 species of fish. Alewife Alosa pseudoharengus made up 48–79% by weight of the diet of brown trout Salmo trutta, chinook salmon Oncorhynchus tshawytscha, coho salmon Oncorhynchus kisutch, lake trout Salvelinus namaycush, and rainbow trout Salmo gairdneri. Alewives eaten ranged from 23 to 245 mm total length; 46% were 150–200 mm. Rainbow smelt Osmerus mordax eaten were 21–245 mm long and made up 4–11% of the salmoninesˈ prey. There were significant direct linear relationships between lengths of alewives and rainbow smelt eaten and lengths of the five predators. Alewives are currently declining in Lake Michigan. If their population collapses, there should be a shift to alternative prey species. We have seen no such shift through 1982, although more recent data of other investigators show a decline in the importance of alewife in salmonine diets. Diets of the midwater‐feeding chinook and coho salmon were heavily dominated by the pelagic alewife, whereas brown and lake trout diets were more diverse. This suggests that trout should have better survival and growth than salmon, because trout would be able to utilize the more benthic yellow perch, Perca flavescens, rainbow smelt, and, to some degree, bloater Coregonus hoyi. The latter species are becoming more abundant with the decline in alewife. Under the current salmonine stocking regime, alewives will continue to supply a lower and variable portion of the salmonine diet, and predatory pressure on alewife should lead to increases in endemic prey speciesˈ populations.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141728/1/tafs0677.pd

Family caregiver quality of life in multiple sclerosis among Kuwaitis: a controlled study

<p>Abstract</p> <p>Background</p> <p>Research interest in the quality of life (QOL) of persons with multiple sclerosis (MS) has been spurred by the need to broaden outcome measures. Far less of this interest has been directed at the family caregivers, who bear most of the burden of care. The objectives of the study were: First, to compare the subjective QOL of family caregivers of persons with relapsing remitting and progressive MS, with those of a matched general population sample and caregivers of diabetes and psychiatric patients. Second, to assess the relationship of QOL with caregiver attitudes to MS and patient's variables.</p> <p>Methods</p> <p>Consecutive MS clinic attendees were assessed with the 26 – item WHOQOL Instrument, and for depression and disability. Similarly, caregivers independently rated their own QOL as well as their impression of patients' QOL and attitudes to patients' illness.</p> <p>Results</p> <p>The 170 caregivers, mean age 35.7 years, had no significant diagnostic differences in QOL domain scores and attitudes to MS. Caregivers had significantly lower QOL than the general population control group for five out of six domains and the general facet (P < 0.01), but higher QOL than the patients. When the scores were corrected for patients' depression and disability, caregivers had similar QOL with the general population group for four domains. Using corrected scores, MS caregivers had lower scores than diabetic and psychiatric caregivers in the physical, psychological and social relations domains. Majority expressed negative attitudes to MS. Caregiver QOL was more affected by their fear of having MS than their feelings about the illness and caregiving role. Caregiver attitudes had mostly no significant impact on their proxy ratings of patients' QOL. The significant predictor of caregivers' overall QOL was their impression of patients' QOL.</p> <p>Conclusion</p> <p>Caregivers need specific attention if they are less educated, unemployed, afraid of having MS and caring for patients with longer duration of illness and less education. In particular, attention to patients' depression and disability could improve caregivers' QOL. Caregivers need specific programs to address fear of having MS, negative attitudes to illness and their unmet needs.</p

BAGGER: An EBL System that Extends and Generalizes Explanations

Coordinated Science Laboratory was formerly known as Control Systems LaboratoryNational Science Foundation / NSF IST 85-1154