scholarly journals The visual processing of motion-defined transparency

2007 ◽  
Vol 274 (1613) ◽  
pp. 1049-1057 ◽  
Author(s):  
William Curran ◽  
Paul B Hibbard ◽  
Alan Johnston

Our understanding of how the visual system processes motion transparency, the phenomenon by which multiple directions of motion are perceived to coexist in the same spatial region, has grown considerably in the past decade. There is compelling evidence that the process is driven by global-motion mechanisms. Consequently, although transparently moving surfaces are readily segmented over an extended space, the visual system cannot separate two motion signals that coexist in the same local region. A related issue is whether the visual system can detect transparently moving surfaces simultaneously or whether the component signals encounter a serial ‘bottleneck’ during their processing. Our initial results show that, at sufficiently short stimulus durations, observers cannot accurately detect two superimposed directions; yet they have no difficulty in detecting one pattern direction in noise, supporting the serial-bottleneck scenario. However, in a second experiment, the difference in performance between the two tasks disappears when the component patterns are segregated. This discrepancy between the processing of transparent and non-overlapping patterns may be a consequence of suppressed activity of global-motion mechanisms when the transparent surfaces are presented in the same depth plane. To test this explanation, we repeated our initial experiment while separating the motion components in depth. The marked improvement in performance leads us to conclude that transparent motion signals are represented simultaneously.

2021 ◽  
Author(s):  
Renate Kat ◽  
Berry van den Berg ◽  
Matthijs J.L. Perenboom ◽  
Maarten Schenke ◽  
Arn M.J.M. van den Maagdenberg ◽  
...  

The mouse is widely used as an experimental model to study visual processing. To probe how the visual system detects changes in the environment, functional paradigms in freely behaving mice are strongly needed. We developed and validated the first EEG-based method to investigate visual deviance detection in freely behaving mice. Mice with EEG implants were exposed to a visual deviant detection paradigm that involved changes in light intensity as standard and deviant stimuli. By subtracting the standard from the deviant evoked waveform, deviant detection was evident as bi-phasic negativity (starting around 70 ms) in the difference waveform. Additionally, deviance-associated evoked (beta/gamma) and induced (gamma) oscillatory responses were found. We showed that the results were stimulus independent by applying a 'flip-flop' design and the results showed good repeatability in an independent measurement. Together, we put forward a validated, easy-to-use paradigm to measure visual deviance processing in freely behaving mice.


2018 ◽  
Author(s):  
Sigit Haryadi

We cannot be sure exactly what will happen, we can only estimate by using a particular method, where each method must have the formula to create a regression equation and a formula to calculate the confidence level of the estimated value. This paper conveys a method of estimating the future values, in which the formula for creating a regression equation is based on the assumption that the future value will depend on the difference of the past values divided by a weight factor which corresponding to the time span to the present, and the formula for calculating the level of confidence is to use "the Haryadi Index". The advantage of this method is to remain accurate regardless of the sample size and may ignore the past value that is considered irrelevant.


2010 ◽  
Vol 100 (3) ◽  
pp. 1163-1194 ◽  
Author(s):  
Robert E Hall ◽  
Susan E Woodward

Entrepreneurship is risky. We study the risk facing a well-documented and important class of entrepreneurs, those backed by venture capital. Using a dynamic program, we calculate the certainty-equivalent of the difference between the cash rewards that entrepreneurs actually received over the past 20 years and the cash that entrepreneurs would have received from a risk-free salaried job. The payoff to a venture-backed entrepreneur comprises a below-market salary and a share of the equity value of the company when it goes public or is acquired. We find that the typical venture-backed entrepreneur received an average of $5.8 million in exit cash. Almost three-quarters of entrepreneurs receive nothing at exit and a few receive over a billion dollars. Because of the extreme dispersion of payoffs, an entrepreneur with a coefficient of relative risk aversion of two places a certainty equivalent value only slightly greater than zero on the distribution of outcomes she faces at the time of her company's launch. (JEL G24, G32, L26, M13)


Author(s):  
Angela Duckworth ◽  

In tandem with increases in delay of gratification, the human capacity for abstract reasoning has increased enormously over the past century. This phenomenon is called the Flynn Effect, after the political scientist who discovered it. I first learned about the Flynn Effect in graduate school. I remember thinking it was impossible. How could it be that as a species, we're getting smarter? And not just a little bit smarter. The size of the Flynn Effect is staggering: more than 30 IQ points—the difference between getting an average score on a standard intelligence test versus qualifying as mentally gifted. Gains are comparable in all areas of the United States and, indeed, around the world.


2021 ◽  
Vol 26 (4) ◽  
pp. 3-7
Author(s):  
Fabien Gagnon ◽  
Les Kertay

Abstract Claims of occupational psychiatric disability have increased considerably over the past 20 years. To avoid psychiatric disability overdiagnosis, it is important to improve the clinical assessment of mental health work disability. This article discusses general disability issues and their impact on individual well-being, social participation, and frequently associated poverty. It defines the difference between impairment assessment and disability assessment, explores three common disability models, and raises issues about psychiatric disability and its potential overdiagnosis.


2013 ◽  
Vol 13 (21) ◽  
pp. 10795-10806 ◽  
Author(s):  
H. H. Aumann ◽  
A. Ruzmaikin

Abstract. Deep convective clouds (DCCs) have been widely studied because of their association with heavy precipitation and severe weather events. Changes in the properties of DCCs are likely in a changing climate. Ten years of data collected by Atmospheric Infrared Sounder (AIRS) allow us to identify decadal trends in frequency of occurrence of DCCs over land and ocean. In the past, DCCs have been identified in the thermal infrared by three methods: (1) thresholds based on the absolute value of an atmospheric window channel brightness temperature; (2) thresholds based on the difference between the brightness temperature in an atmospheric window channel and the brightness temperature centered on a strong water vapor absorption line; and (3) a threshold using the difference between the window channel brightness temperature and the tropopause temperature based on climatology. Simultaneous observations of these infrared identified DCCs with the Advanced Microwave Sounding Unit–Humidity Sounder for Brazil (AMSU-HSB) using 183 GHz water channels provide a statistical correlation with microwave deep convection and overshooting convection. In the past 10 years, the frequency of occurrence of DCCs has decreased for the tropical ocean, while it has increased for tropical land. The area of the tropical zone associated with DCCs is typically much less than 1%. We find that the least frequent, more extreme DCCs show the largest trend in frequency of occurrence, increasing over land and decreasing over ocean. The trends for land and ocean closely balance, such that the DCC frequency changed at an insignificant rate for the entire tropical zone. This pattern of essentially zero trend for the tropical zone, but opposite land/ocean trends, is consistent with measurements of global precipitation. The changes in frequency of occurrence of the DCCs are correlated with the Niño34 index, which defines the sea surface temperature (SST) anomaly in the east-central Pacific. This is also consistent with patterns seen in global precipitation. This suggests that the observed changes in the frequency are part of a decadal variability characterized by shifts in the main tropical circulation patterns, which does not fully balance in the 10-year AIRS data record. The regional correlations and anti-correlations of the DCC frequency anomaly with the Multivariate ENSO Index (MEI) provide a new perspective for the regional analysis of past events, since the SST anomaly in the Nino34 region is available in the form of the extended MEI from 1871.


2017 ◽  
Vol 117 (1) ◽  
pp. 388-402 ◽  
Author(s):  
Michael A. Cohen ◽  
George A. Alvarez ◽  
Ken Nakayama ◽  
Talia Konkle

Visual search is a ubiquitous visual behavior, and efficient search is essential for survival. Different cognitive models have explained the speed and accuracy of search based either on the dynamics of attention or on similarity of item representations. Here, we examined the extent to which performance on a visual search task can be predicted from the stable representational architecture of the visual system, independent of attentional dynamics. Participants performed a visual search task with 28 conditions reflecting different pairs of categories (e.g., searching for a face among cars, body among hammers, etc.). The time it took participants to find the target item varied as a function of category combination. In a separate group of participants, we measured the neural responses to these object categories when items were presented in isolation. Using representational similarity analysis, we then examined whether the similarity of neural responses across different subdivisions of the visual system had the requisite structure needed to predict visual search performance. Overall, we found strong brain/behavior correlations across most of the higher-level visual system, including both the ventral and dorsal pathways when considering both macroscale sectors as well as smaller mesoscale regions. These results suggest that visual search for real-world object categories is well predicted by the stable, task-independent architecture of the visual system. NEW & NOTEWORTHY Here, we ask which neural regions have neural response patterns that correlate with behavioral performance in a visual processing task. We found that the representational structure across all of high-level visual cortex has the requisite structure to predict behavior. Furthermore, when directly comparing different neural regions, we found that they all had highly similar category-level representational structures. These results point to a ubiquitous and uniform representational structure in high-level visual cortex underlying visual object processing.


2021 ◽  
Vol 10 (1) ◽  
pp. 45
Author(s):  
Khairunnisa Musari

Pandemic brings a crisis. This makes world leaders have to work hard and smartly in managing state budgets. During the heyday of Islam, Muslims also faced crises. Given that time the power of Islam mastered many areas of the world, it can be assumed that the crisis that occurred in the past was a global crisis as it is happening today. The difference is the crisis that occurred at the time because of losing the war. This paper tries to describe the historical experience of the esham, one of the fiscal instruments in the Islamic world that helped the Ottoman Empire overcome the crisis. Esham has mobilized low-cost funds from the public in a relatively concise time. Esham served as a better choice than looking for foreign debt. As the origin of sukuk, esham has simpler structure so that can be used as an alternative to sukuk with a lower cost. To deal with a crisis, esham may intervene in the economy. Esham funds to the real sector in turn will help the government drive the economy as well as control prices in the market for goods and services. Therefore, esham has the potential in facing the crisis.


2021 ◽  
pp. 90-96
Author(s):  
A. V. Kotov ◽  
V. I. Desyaterik ◽  
S. P. Mikhno

Summary. Purpose of the reserche. To study changes in microflora and sensitivity of isolated strains to antibiotics using bacteriological research methods for intra-abdominal infections and peritonitis to determine their resistance when planning antibiotic therapy. Results and discussion. The paper presents data from a retrospective analysis of the results of studies of microflora and its resistance in intra-abdominal infections (IAI) and peritonitis for 2 periods: I period — from january 2007 to december 2008, II period — from january 2018 to december 2019. The difference between period II and I was in the increase in the number of individual pathogenic strains of microorganisms. Thus, the number of Klebsiella spp. increased from 13.8 % to 23.8 %, which in absolute number of their total number amounted to a 73.5 %, ranking second in the overall structure among pathogens sown in IAI and peritonitis. The number of strains of Staphylococcus spp., Enterobacter spp., Acinetobacter spp. has also increased by 2.4–5.8 % respectively. Among the strains Klebsiella spp., E. coli and Staphylococcus spp. the number of poly- and multi-polyresistant forms has increased. Thus, the number of such forms among Klebsiella spp. increased from 19.2 to 44.5 %, Staphylococcus spp. — from 43.8 to 67.1 % and E. coli from 18.2 to 23.5 %, respectively. Conclusions. Over the past 10 years, with IAI and peritonitis, the most significant changes were revealed on the part of pathogenic strains of Klebsiella spp., Staphylococcus spp. and Acinetobacter spp. Multidrug resistant strains were predominantly susceptible to carbapenems, semisynthetic ureidopenicillins, aminoglycosides, glycopeptides, oxazalidinones, phosphonoic acid derivatives. In the context of changes in the microbial landscape observed over the past decade, an increase in the number of poly- and multi-resistant forms of pathogenic microorganisms in IAI and peritonitis, the choice of antibiotics for rational therapy should be based solely on bacterioscopy and antibiograms.


2021 ◽  
Vol 24 (5) ◽  
pp. 46-53
Author(s):  
Oleksandr O. Borshch ◽  
Oleksandr V. Borshch ◽  
Yurii Mashkin ◽  
Vasyl Malina ◽  
Maxim Fedorchenko

Over the past 20 years, dairy farms in Ukraine have been actively introducing the keeping of cows in easy-to-assemble premises. However, in a moderate climate (with four distinct year seasons), the issues of microclimate, energy losses of animals and their behavior during the cold period of the year for keeping in such premises have not been fully studied. The purpose of this work was to study the influence of the heat insulation elements use of side curtains in easy-to-assemble premises during the period of low temperatures on microclimate, energy outgoings for thermoregulation and behavior of cows. The research conducted in the central part of Ukraine (Kyiv region). The research was conducted during January-February (29-43 days of the year) 2021. This period characterized by low average daily temperatures of -12.2– -18.7°С, strong wind gusts and daily precipitation in the form of snow. Two easy-toassemble premises for 400 heads were used for research. Parameters of placements (LxWxH): 150х32х10.5 m. The first one was without the use of curtains heat insulation elements, and the second one was with these elements of heat insulation. It was found that the use of polycarbonate wall heat insulation elements had a positive effect on the microclimate in the placement during the period of low temperatures. Indicators of average daily air temperatures in the placement were 3.2 and 8.8°C higher compared to the temperature in the same premise without the use of heat insulation elements and the environment. The wind speed also differed by 0.18 and 11.04 m/s, respectively. In addition, the heat insulation of the walls affected the temperature under the lying cow (+1.8°C), energy outgoings for thermoregulation (-1.93 MJ) and the number of cows that lay in the period of the lowest temperatures (+3.23-9.83%) compared to the placement without heat insulation elements. The difference in temperature of rubber carpet in the compared premises was significant: +3.3°C in the premises with heat insulation elements compared to the premises without heat insulation


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