Trade-Off between Achromatic Colour and Perceived Illumination as Revealed by the Use of Pseudoscopic Inversion of Apparent Depth

Perception ◽  
1994 ◽  
Vol 23 (9) ◽  
pp. 1007-1023 ◽  
Author(s):  
Alexander Logvinenko ◽  
Galina Menshikova
Keyword(s):  
Apparent Depth ◽  
Bisection Method ◽  
Trade Off ◽  
Classical Form ◽  
Inverse Proportion ◽  
The Mean ◽  
Contrast Range

The albedo hypothesis was tested under apparent transformations of perceived illumination and achromatic colour induced by pseudoscopic inversion of apparent depth. Looking through a pseudoscope made a cone attached to a vertical white screen look like a conical hole in the screen. This in turn caused the shadow which the now ‘invisible’ cone cast on the screen to change its appearance and to look like a darkly pigmented area. The darkness of the shadow before the pseudoscopic reversal and greyness of colour afterwards were measured by means of psychophysical scales for darkness and greyness set by the bisection method. Contrast of the shaded area was varied from 0.17 to 0.96 in 7 steps, the mean illuminance of the screen having been maintained at 40 lx. Although the albedo hypothesis in its classical form was not confirmed, it was found that darkness of shadow varied linearly in inverse proportion to greyness of colour within the entire contrast range. This is in agreement with the hypothesis that achromatic colour and perceived illumination are inversely proportional to each other while the retinal illumination is constant.

Celiac Disease in Kosovar Albanian Children: Evaluation of Clinical Features and Diagnosis

2020 ◽  
Vol 16 (3) ◽  
pp. 241-247
Author(s):  
Atifete Ramosaj-Morina ◽  
Alije Keka-Sylaj ◽  
Arbana Baloku Zejnullahu ◽  
Lidvana Spahiu ◽  
Virgjina Hasbahta ◽  
...  
Keyword(s):  
Celiac Disease ◽  
Disease Onset ◽  
Clinical Manifestations ◽  
Gastrointestinal Symptoms ◽  
Dominant Mode ◽  
Primary School Children ◽  
Cross Sectional ◽  
Classical Form ◽  
Wide Range ◽  
The Mean

Background: Celiac disease is an immune-mediated disorder characterized by variable clinical manifestations, specific antibodies, HLA-DQ2/DQ8 haplotypes, and enteropathy. Objectives: The aim of this study was to present the clinical spectrum and patterns of celiac disease in Kosovar Albanian children. Methods: A cross-sectional retrospective study was performed with Albanian children aged 0-18 years, treated for celiac disease in the Pediatric Clinic, University Clinical Center of Kosovo from 2005 to 2016. Results: During the study period, 63 children were treated for celiac disease. The mean age at diagnosis was 5.5 years (SD ± 3.31). The mean age at celiac disease onset was 3.3 years (SD ± 2.02), while the mean delay from the first symptoms indicative of celiac disease to diagnosis was 2.2 years (SD ± 2.09). More than 70% of the patients were diagnosed in the first 7 years of life, mainly presented with gastrointestinal symptoms, while primary school children and adolescents mostly showed atypical symptoms (p<0.001). The classical form of celiac disease occurred in 78% of the cases. Sixty (95%) patients carried HLA-DQ2.5, DQ2.2 and/or HLA-DQ8 heterodimers, and only three of them tested negative. Conclusions: Kosovo, as the majority of developing countries, is still facing the classical form of celiac disease as the dominant mode of presentation; as a result, most children with other forms of the celiac disease remain undiagnosed. : Physicians should be aware of the wide range of clinical presentations and utilize low testing thresholds in order to prevent potential long-term problems associated with untreated celiac disease.

Nitrogen use efficiency: does a trade-off exist between the N productivity and the mean residence time within species?

2008 ◽  
Vol 56 (3) ◽  
pp. 272 ◽  
Author(s):  
Zhi Y. Yuan ◽  
Han Y. H. Chen ◽  
Ling H. Li
Keyword(s):  
Residence Time ◽  
Nitrogen Use Efficiency ◽  
Mean Residence Time ◽  
Negative Relationship ◽  
Controlled Experiments ◽  
Nitrogen Use ◽  
Trade Off ◽  
N Supply ◽  
Use Efficiency ◽  
The Mean

Nitrogen use efficiency (NUE) can be divided into two components, i.e. N productivity (A) and the mean residence time (MRT). Controlled experiments indicate that there is not a trade-off between A and MRT within species, but this theory has not been well tested in field conditions. Here, we studied the A, MRT and NUE of Stipa krylovii Roshev. in a grassland over 4 years of N fertilisation experimentation. The three parameters (A, MRT and NUE) were significantly related to soil N supply and there was a negative relationship between A and MRT within this species (r = –0.775, P < 0.05), i.e. plants with higher A had lower MRT. Our results showed a trade-off between A and MRT within this Stipa species and this observed trade-off was attributed to different responses of A and MRT to soil fertility.

scholarly journals Do DJIA Firms Reflect Stationary Debt Ratios?

Economies ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 76
Author(s):  
Feng-Li Lin
Keyword(s):  
Capital Structure ◽  
Stationary Processes ◽  
Debt Ratio ◽  
Pecking Order ◽  
Trade Off ◽  
Listed Firms ◽  
Growth Opportunity ◽  
Dow Jones Industrial Average ◽  
The Mean ◽  
The Stability

To form optimum firm capital structure strategies to face unanticipated economic events, firm managers should understand the stability of a firm’s capital structure. The aim of this research was to study whether the debt ratio is stationary in listed firms on the Dow Jones Industrial Average (DJIA). Two vital capital structure concepts regarding pecking order and trade-off theory are fairly contradictory. Using opposing theoretical contexts, the Sequential Panel Selection Method apparently categorizes which and how many series are stationary processes in the panel. This method was used to test the mean reverting properties of the 25 companies listed on Dow Jones Industrial Average between 2001 and 2017 in this study, which is expected to fill the current gap in the literature. The overall results show that stationary debt ratios exist in 10 of the 25 studied firms, supporting the trade-off theory. Moreover, the 10 firms utilizing trade-off theory are affected by firm size, profitability, growth opportunity, and dividend payout ratio. These results provide vital information for firms to certify strategies to optimize capital structure.

scholarly journals Patient willingness to be seen by a physician associate in Ireland

2018 ◽  
Vol 4 (2) ◽  
pp. 41 ◽  
Author(s):  
Pauline Joyce ◽  
Richard Arnett ◽  
Arnold Hill ◽  
Roderick S. Hooker
Keyword(s):  
Patient Preference ◽  
Medical Condition ◽  
Wait Time ◽  
Mixed Methods Study ◽  
Medical Provider ◽  
Specific Patient ◽  
Trade Off ◽  
Knowing That ◽  
The Mean ◽  
Gender Specific

Background: The physician associate (PA) role was piloted in Dublin, Ireland between 2015 and 2017. However, the concept of a PA and the acceptance of their role in Ireland had not been explored.Objective: To investigate the willingness of Irish citizens to be seen by a PA based on medical scenarios in a typical clinical setting.Design: A mixed methods study was undertaken. A preference survey, with three medical scenarios, gave participants a choice to be treated by a PA or a doctor, with two time trade-off options offered. Responses were supported with qualitative text. Four hundred people were invited to participate as surrogate patients.Setting and participants: In 2017 a total of 270 respondents took part in the study (67.5%) in two hospitals (one private and one public) in Dublin. The mean age was 60; male (n = 142) and female (n = 128) respondents.Findings: In total, 95% of the respondents chose to see a PA over a doctor based on the scenarios presented and a wait time of 30 minutes. Wait time, trust, competency and the severity or seriousness of the medical condition were categorized into three themes for choosing the PA over the doctor. The “surrogate patient” decisions made by this sample were influenced by knowing that the PA is supervised and can check decisions with his/her supervizing physician.Conclusion: These findings are consistent with studies carried out in other countries where willingness to be seen by a PA is neither age nor gender specific. Patient preference seems to concur around the importance of trust and confidence in the medical provider.

SOME REMARKS ON MEAN-VARIANCE HEDGING FOR DISCONTINUOUS ASSET PRICE PROCESSES

2005 ◽  
Vol 08 (04) ◽  
pp. 425-443 ◽  
Author(s):  
TAKUJI ARAI
Keyword(s):  
Asset Price ◽  
Jump Diffusion ◽  
Diffusion Models ◽  
Continuous Case ◽  
Martingale Measure ◽  
Trade Off ◽  
One Dimensional ◽  
The Mean ◽  
Duality Approach ◽  
Mean Variance

Mean-variance hedging for the discontinuous semimartingale case is obtained under some assumptions related to the variance-optimal martingale measure. In the present paper, two remarks on it are discussed. One is an extension of Hou–Karatzas' duality approach from the continuous case to discontinuous. Another is to prove that there is the consistency with the case where the mean-variance trade-off process is continuous and deterministic. In particular, one-dimensional jump diffusion models are discussed as simple examples.

scholarly journals Effectiveness of Adaptive Real-Time Closures for Managing Migratory Species in Data-Limited Multispecies Fisheries

2021 ◽  
Vol 34 (4) ◽  
Author(s):  
MASAMI MUNEHARA ◽  
◽  
METHEE KAEWNERN ◽  
PAVAROT NORANARTTRAGOON ◽  
TAKASHI FRITZ MATSUISHI
Keyword(s):  
Real Time ◽  
Fisheries Management ◽  
Single Species ◽  
Management Tool ◽  
Migratory Species ◽  
Sensitive Species ◽  
Trade Off ◽  
Multispecies Fisheries ◽  
Relative Value ◽  
The Mean

Fixed closure (FC) is a standard fisheries management tool for protecting sensitive species or species requiring conservation. However, an FC might not effectively manage migratory species because of the large uncertainties of their migration. Adaptive real-time closure (ARTC) is a tool that updates closure areas according to the latest information. This study aimed to evaluate the effectiveness of ARTC to conserve sensitive species for data-limited fisheries by a series of simulations using migration models with hotspots. In the single species simulation, the conservation ratio for the sensitive species in FC varies widely at greater migration uncertainty. In ARTC, a longer duration of a hotspot resulted in a higher conservation ratio. When the mean duration of hotspots was medium or long, the conservation ratio for the sensitive species was more than 50 % in more than 99 % of the simulation trials. In multispecies fisheries, a clear trade-off was observed between the conservation ratio of sensitive species and other species. ARTC was more effective than whole closure when the proportion of sensitive species was high or without closure when the proportion was low. Conditions in which ARTC was most appropriate were described for hotspot duration, increased numbers of individuals in a hotspot, and the relative value of conservation, representing the ratio of the value of conserving sensitive species to one of catching other species.

scholarly journals Lognormal firing rate distribution reveals prominent fluctuation–driven regime in spinal motor networks

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Peter C Petersen ◽  
Rune W Berg
Keyword(s):  
Neuronal Population ◽  
Output Curve ◽  
Input Output ◽  
Rhythmic Movements ◽  
Trade Off ◽  
Firing Rates ◽  
Spinal Motor ◽  
Rich Diversity ◽  
The Mean ◽  
Lumbar Spinal

When spinal circuits generate rhythmic movements it is important that the neuronal activity remains within stable bounds to avoid saturation and to preserve responsiveness. Here, we simultaneously record from hundreds of neurons in lumbar spinal circuits of turtles and establish the neuronal fraction that operates within either a ‘mean-driven’ or a ‘fluctuation–driven’ regime. Fluctuation-driven neurons have a ‘supralinear’ input-output curve, which enhances sensitivity, whereas the mean-driven regime reduces sensitivity. We find a rich diversity of firing rates across the neuronal population as reflected in a lognormal distribution and demonstrate that half of the neurons spend at least 50 % of the time in the ‘fluctuation–driven’ regime regardless of behavior. Because of the disparity in input–output properties for these two regimes, this fraction may reflect a fine trade–off between stability and sensitivity in order to maintain flexibility across behaviors.

scholarly journals A lack of repeatability creates the illusion of a trade-off between basal and plastic cold tolerance

2021 ◽  
Author(s):  
Erica O’Neill ◽  
Hannah E. Davis ◽  
Heath A. MacMillan
Keyword(s):  
Cold Tolerance ◽  
Thermal Tolerance ◽  
Regression To The Mean ◽  
Trade Off ◽  
Physiological Constraints ◽  
Chill Coma ◽  
Physiological Constraint ◽  
The Mean ◽  
High And Low Temperatures ◽  
The Individual

AbstractThe thermotolerance-plasticity trade-off hypothesis predicts that ectotherms with greater basal thermal tolerance have a lower acclimation capacity. This hypothesis has been tested at both high and low temperatures but the results often conflict. If basal tolerance constrains plasticity (e.g. through shared mechanisms that create physiological constraints), it should be evident at the level of the individual, provided the trait measured is repeatable. Here, we used chill-coma onset temperature and chill-coma recovery time (CCO and CCRT; non-lethal thermal limits) to quantify cold tolerance of Drosophila melanogaster across two trials (pre- and post-acclimation). Cold acclimation improved cold tolerance, as expected, but individual measurements of CCO and CCRT in non-acclimated flies were not (or only slightly) repeatable. Surprisingly, however, there was still a strong correlation between basal tolerance and plasticity in cold-acclimated flies. We argue that this relationship is a statistical artefact (specifically, a manifestation of regression to the mean; RTM) and does not reflect a true trade-off or physiological constraint. Thermal tolerance trade-off patterns in previous studies that used similar methodology are thus likely to be impacted by RTM. Moving forward, controlling and/or correcting for RTM effects is critical to determining whether such a trade-off or physiological constraint truly exists.

scholarly journals STOCK RETURNS, VOLATILITY AND MEAN REVERSION IN EMERGING AND DEVELOPED FINANCIAL MARKETS

2018 ◽  
Vol 24 (3) ◽  
pp. 1149-1177 ◽  
Author(s):  
Rizwan Raheem AHMED ◽  
Jolita VVEINHARDT ◽  
Dalia ŠTREIMIKIENĖ ◽  
Saghir Pervaiz GHAURI
Keyword(s):  
Emerging Markets ◽  
Stock Returns ◽  
Stock Markets ◽  
Mean Reversion ◽  
Conditional Variance ◽  
Trade Off ◽  
Risk Return ◽  
Developed Markets ◽  
The Mean ◽  
Developed Stock Markets

The objective of this research is to measure and examine volatilities between important emerging and developed stock markets and to ascertain a relationship between volatilities and stock returns. This research paper also analyses the Mean reversion phenomenon in emerging and developed stock markets. For this purpose, seven emerging markets and five developed markets were considered. Descriptive statistics showed that the emerging markets have higher returns with the higher risk-return trade-off. In contrast, developed markets have low annual returns with a low risk-return trade-off. Correlation analysis indicated the significant positive correlation among the developed markets, but emerging and developed markets have shown relatively insignificant correlation. Results of ARCH and GARCH revealed that the value of likelihood statistics ratio is large, that entails the GARCH (1,1) model is a lucrative depiction of daily return pattern, that effectively and efficiently capturing the orderly reliance of volatility. The findings of the study showed that the estimate ‘β’ coefficients given in conditional variance equation are significantly higher than the ‘α’, this state of affair entails that bigger market surprises tempt comparatively small revision in future volatility. Lastly, the diligence of the conditional variance estimated by α + β is significant and proximate to integrated GARCH (1,1) model, thus, this indicates, the existing evidence is also pertinent in order to forecast the future volatility. The results signified that the sum of GARCH (1,1) coefficients for all the equity returns’ is less than 1 that is an important condition for mean reversion, as the sum gets closer to 1, hence the Mean reversion process gets slower for all the emerging and developed stock markets.

scholarly journals Derivatives pricing via p-optimal martingale measures: some extreme cases

2006 ◽  
Vol 43 (03) ◽  
pp. 634-651
Author(s):  
Marina Santacroce
Keyword(s):  
Asset Price ◽  
Martingale Measure ◽  
Power Utility ◽  
Derivatives Pricing ◽  
Trade Off ◽  
Continuous Semimartingale ◽  
Backward Equation ◽  
The Mean ◽  
Necessary And Sufficient ◽  
Mean Variance

In an incomplete financial market in which the dynamics of the asset prices is driven by a d-dimensional continuous semimartingale X, we consider the problem of pricing European contingent claims embedded in a power utility framework. This problem reduces to identifying the p-optimal martingale measure, which can be given in terms of the solution to a semimartingale backward equation. We use this characterization to examine two extreme cases. In particular, we find a necessary and sufficient condition, written in terms of the mean-variance trade-off, for the p-optimal martingale measure to coincide with the minimal martingale measure. Moreover, if and only if an exponential function of the mean-variance trade-off is a martingale strongly orthogonal to the asset price process, the p-optimal martingale measure can be simply expressed in terms of a Doléans-Dade exponential involving X.

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