Spatial contrast sensitivity and external noise: applications to optical and neural modulation transfer functions

The thesis will show how to equalise the effect of quantal noise across spatial frequencies by keeping the retinal flux (If-2) constant. In addition, quantal noise is used to study the effect of grating area and spatial frequency on contrast sensitivity resulting in the extension of the new contrast detection model describing the human contrast detection system as a simple image processor. According to the model the human contrast detection system comprises low-pass filtering due to ocular optics, addition of light dependent noise at the event of quantal absorption, high-pass filtering due to the neural visual pathways, addition of internal neural noise, after which detection takes place by a local matched filter, whose sampling efficiency decreases as grating area is increased. Furthermore, this work will demonstrate how to extract both the optical and neural modulation transfer functions of the human eye. The neural transfer function is found to be proportional to spatial frequency up to the local cut-off frequency at eccentricities of 0 - 37 deg across the visual field. The optical transfer function of the human eye is proposed to be more affected by the Stiles-Crawford -effect than generally assumed in the literature. Similarly, this work questions the prevailing ideas about the factors limiting peripheral vision by showing that peripheral optical acts as a low-pass filter in normal viewing conditions, and therefore the effect of peripheral optics is worse than generally assumed.

Effects of yellow filters on visual acuity, contrast sensitivity and reading under conditions of forward light scatter

Background Yellow filters are sometimes recommended to people with low vision. Our aim was investigate the effects of three commercial yellow filters on visual acuity and contrast sensitivity (with and without glare) and reading (without glare) under conditions of forward light scatter (FLS). Method Fifty-five healthy subjects were assessed with Corning Photochromic Filters (CPFs) 450, 511 and 527 and a filter producing FLS. The effects on log MAR visual acuity, Pelli–Robson contrast sensitivity with and without glare, and reading (measured with MNRead charts) without glare were determined. Results Statistically significant differences were found between the overall effect of glare and between CPFs for visual acuity and contrast sensitivity. A gradual decline in visual acuity, contrast sensitivity and reading with increasing CPF absorption was noted. Conclusion Effects of CPF450, 511, 527 on visual acuity, contrast sensitivity and reading under conditions of FLS were negative but not clinically significant.

Maternal mind-mindedness during infancy, general parenting sensitivity and observed child feeding behavior:a longitudinal study

Maternal mind-mindedness, or the tendency to view the child as a mental agent, has been shown to predict sensitive and responsive parenting behavior. As yet the role of mind-mindedness has not been explored in the context of feeding interactions. This study evaluates the relations between maternal mind-mindedness at 6 months of infant age and subsequently observed maternal sensitivity and feeding behaviors with children at age 1 year. Maternal mind-mindedness was greater in mothers who had breast-fed compared to formula-fed. Controlling for breast-feeding, mind-mindedness at 6 months was correlated with observations of more sensitive and positive feeding behaviors at 1 year of age. Mind-mindedness was also associated with greater general maternal sensitivity in play and this general parenting sensitivity mediated the effect of mind-mindedness on more sensitive and positive feeding behaviors. Interventions to promote maternal tendency to consider their child's mental states may encourage more adaptive parental feeding behaviors. © 2014 Taylor & Francis.

Sensitivity and reliability of objective image analysis compared to subjective grading of bulbar hyperaemia

Aims: To establish the sensitivity and reliability of objective image analysis in direct comparison with subjective grading of bulbar hyperaemia. Methods: Images of the same eyes were captured with a range of bulbar hyperaemia caused by vasodilation. The progression was recorded and 45 images extracted. The images were objectively analysed on 14 occasions using previously validated edge-detection and colour-extraction techniques. They were also graded by 14 eye-care practitioners (ECPs) and 14 non-clinicians (NCb) using the Efron scale. Six ECPs repeated the grading on three separate occasions Results: Subjective grading was only able to differentiate images with differences in grade of 0.70-1.03 Efron units (sensitivity of 0.30-0.53), compared to 0,02-0.09 Efron units with objective techniques (sensitivity of 0.94-0.99). Significant differences were found between ECPs and individual repeats were also inconsistent (p<0.001). Objective analysis was 16x more reliable than subjective analysis. The NCLs used wider ranges of the scale but were more variable than ECPs, implying that training may have an effect on grading. Conclusions: Objective analysis may offer a new gold standard in anterior ocular examination, and should be developed further as a clinical research tool to allow more highly powered analysis, and to enhance the clinical monitoring of anterior eye disease.

Sensitivity and Bias within the Binary Signal Detection Theory, BSDT

Similar to classic Signal Detection Theory (SDT), recent optimal Binary Signal Detection Theory (BSDT) and based on it Neural Network Assembly Memory Model (NNAMM) can successfully reproduce Receiver Operating Characteristic (ROC) curves although BSDT/NNAMM parameters (intensity of cue and neuron threshold) and classic SDT parameters (perception distance and response bias) are essentially different. In present work BSDT/NNAMM optimal likelihood and posterior probabilities are analytically analyzed and used to generate ROCs and modified (posterior) mROCs, optimal overall likelihood and posterior. It is shown that for the description of basic discrimination experiments in psychophysics within the BSDT a ‘neural space’ can be introduced where sensory stimuli as neural codes are represented and decision processes are defined, the BSDT’s isobias curves can simultaneously be interpreted as universal psychometric functions satisfying the Neyman-Pearson objective, the just noticeable difference (jnd) can be defined and interpreted as an atom of experience, and near-neutral values of biases are observers’ natural choice. The uniformity or no-priming hypotheses, concerning the ‘in-mind’ distribution of false-alarm probabilities during ROC or overall probability estimations, is introduced. The BSDT’s and classic SDT’s sensitivity, bias, their ROC and decision spaces are compared.

Brief report:effects of sensory sensitivity and intolerance of uncertainty on anxiety in mothers of children with autism spectrum disorder

This study examined the relations between anxiety and individual characteristics of sensory sensitivity (SS) and intolerance of uncertainty (IU) in mothers of children with ASD. The mothers of 50 children completed the Hospital Anxiety and Depression Scale, the Highly Sensitive Person Scale and the IU Scale. Anxiety was associated with both SS and IU and IU was also associated with SS. Mediation analyses showed direct effects between anxiety and both IU and SS but a significant indirect effect was found only in the model in which IU mediated between SS. This is the first study to characterize the nature of the IU and SS interrelation in predicting levels of anxiety.

"Értelem és érzelem" A lakossági ügyfelek gazdasági magatartása és a bankokkal kapcsolatos attitűdjei ("Sense and sensibility" Retail customer behaviours and attitudes towards banks)

A globális pénzügyi és világgazdasági válság sok szempontból újszerű versenyhelyzetet teremtett a lakossági banki piacon az ügyfelek megtartása és az új ügyfelek megszerzése terén. A gazdasági és társadalmi környezetben bekövetkezett változásokhoz való alkalmazkodás sikeressége érdekében fontos a banki ügyfelek gazdasági viselkedésmódjának alaposabb és mélyrehatóbb megértése. Tanulmányunkban bemutatjuk azokat a főbb, releváns pszichológiai, szociológiai és gazdasági tényezőket, amelyek az ügyfelek bankokkal kapcsolatos magatartását és attitűdjeit befolyásolják. A vonatkozó elméleteket és kutatásokat egy konceptuális keretben foglaljuk össze; ennek az alappilléreit a bizalom, a pénzzel kapcsolatos attitűdök és az emocionális komponensek alkotják. _______ The global fi nancial and economic crisis created new competition in the market for retail banking, and in the areas of existing customer retention and new customers’ acquisition. The corresponding economic and social change called for new adaptive strategies on behalf of banks to better understand the economic behaviour of their customers. This paper focuses on certain relevant psychological, sociological and economic factors that tend to characterize customer behaviours and attitudes towards banks. With particular emphasis on highlighting the potential implications of relevant theories for the purposes of banks, our conceptual model incorporates elements of trust, monetary attitudes and underlying emotional components.

Non-Celiac Gluten Sensitivity and Autoimmunity. A Case Report

Introduction, objective: To present a case report in which the finding of non-coeliac gluten sensitivity was decisive for the treatment of a complex autoimmune disease. Materials and methods: A 43-year-old woman with polyarthritis, psoriatic features, anti-SSA/Ro and anti-cyclic citrullinated peptide antibodies, with refractory course, was evaluated for gluten sensitivity despite negative serology for coeliac disease. Results: The patient carried the HLA DQ2 haplotype and duodenal biopsy showed lymphocytic enteritis. A gluten-free diet resolved the clinical picture and permitted tapering of immunosuppressive therapy. Conclusion: Non-coeliac gluten sensitivity can be associated with autoimmunity despite the absence of the specific autoantibodies of coeliac disease.

UV wavelengths experienced during development affect larval newt visual sensitivity and predation efficiency

International audience

Sensitivity and specificity of the Gastrointestinal Short Form Questionnaire in diagnosis of gastroesophageal reflux disease

Introduction: Gastrointestinal Short Form Questionnaire (GSFQ) is a questionnaire for gastroesophageal reflux disease (GERD) diagnosis, with a version in Spanish language, not yet compared to an objective test. Aims: To establish GSFQ diagnostic performance against 24-hour pH monitoring carried out in two tertiary care hospitals. Methods: Consecutive adult patients with typical GERD symptoms (heartburn, regurgitation) referred for pH monitoring fulfilled the GSFQ (score range 0-30, proportional to probability of GERD). Diagnosis of GERD was established when acid exposure time in distal esophagus was superior to 4.5% or symptom association probability was greater than 95%. Receiver-operator characteristic (ROC) curves were calculated and best cut-off score determined, with corresponding sensitivity, specificity and likelihood ratios (LR) (95% confidence interval for each). Results: One hundred and fifty-two patients were included (59.9% women, age 47.9 ± 13.9; 97.4% heartburn; 71.3% regurgitation). pH monitoring was abnormal in 65.8%. Mean GSFQ score was 11.2 ± 6. Area under ROC was 56.5% (47.0-65.9%). Optimal cut-off score was 13 or greater: sensitivity 40% (30.3-50.3%), specificity 71.2% (56.9-82.9%), positive LR 1.39 (0.85-2.26) and negative LR 0.84 (0.67-1.07). Exclusion of questions 1 and 3 of the original GSFQ, easily interpreted as referred to dyspepsia and not GERD, improved only marginally the diagnostic performance: AUROC 59.1%. Conclusion: The GSFQ does not predict results of pH monitoring in patients with typical symptoms in a tertiary care setting.

Sensitivity and specificity of parallel or serial serological testing for detection of canine Leishmania infection

In Brazil, human and canine visceral leishmaniasis (CVL) caused by Leishmania infantum has undergone urbanisation since 1980, constituting a public health problem, and serological tests are tools of choice for identifying infected dogs. Until recently, the Brazilian zoonoses control program recommended enzyme-linked immunosorbent assays (ELISA) and indirect immunofluorescence assays (IFA) as the screening and confirmatory methods, respectively, for the detection of canine infection. The purpose of this study was to estimate the accuracy of ELISA and IFA in parallel or serial combinations. The reference standard comprised the results of direct visualisation of parasites in histological sections, immunohistochemical test, or isolation of the parasite in culture. Samples from 98 cases and 1,327 noncases were included. Individually, both tests presented sensitivity of 91.8% and 90.8%, and specificity of 83.4 and 53.4%, for the ELISA and IFA, respectively. When tests were used in parallel combination, sensitivity attained 99.2%, while specificity dropped to 44.8%. When used in serial combination (ELISA followed by IFA), decreased sensitivity (83.3%) and increased specificity (92.5%) were observed. Serial testing approach improved specificity with moderate loss in sensitivity. This strategy could partially fulfill the needs of public health and dog owners for a more accurate diagnosis of CVL.

Insulin sensitivity and secretion in obese Type 2 diabetic women after various bariatric operations

Objective: To compare the effects of biliopancreatic diversion (BPD) and laparoscopic gastric banding (LAGB) on insulin sensitivity and secretion with the effects of laparoscopic gastric plication (P). Methods: A total of 52 obese women (age 30-66 years) suffering from type 2 diabetes mellitus (T2DM) were prospectively recruited into three study groups: 16 BPD; 16 LAGB, and 20 P. Euglycemic clamps and mixed meal tolerance tests were performed before, at 1 month and at 6 months after bariatric surgery. Beta cell function derived from the meal test parameters was evaluated using mathematical modeling. Results: Glucose disposal per kilogram of fat free mass (a marker of peripheral insulin sensitivity) increased significantly in all groups, especially after 1 month. Basal insulin secretion decreased significantly after all three types of operations, with the most marked decrease after BPD compared with P and LAGB. Total insulin secretion decreased significantly only following the BPD. Beta cell glucose sensitivity did not change significantly post-surgery in any of the study groups. Conclusion: We documented similar improvement in insulin sensitivity in obese T2DM women after all three study operations during the 6-month postoperative follow-up. Notably, only BPD led to decreased demand on beta cells (decreased integrated insulin secretion), but without increasing the beta cell glucose sensitivity.