Effect of rod-cone interactions on mesopic visual performance mediated by chromatic and luminance pathways

We studied the effect of rod–cone interactions on mesopic visual reaction time (RT). Rod and cone photoreceptor excitations were independently controlled using a four-primary photostimulator. It was observed that (1) lateral rod–cone interactions increase the cone-mediated RTs; (2) the rod–cone interactions are strongest when rod sensitivity is maximal in a dark surround, but weaker with increased rod activity in a light surround; and (3) the presence of a dark surround nonselectively increased the mean and variability of chromatic (+L-M, S-cone) and luminance (L+M+S) RTs independent of the level of rod activity. The results demonstrate that lateral rod–cone interactions must be considered when deriving mesopic luminous efficiency using RT.

Impact of simulated hyperopia on academic-related performance in children

Purpose: To investigate the impact of simulated hyperopia and sustained near work on children’s ability to perform a range of academic-related tasks. Methods: Fifteen visually normal children (mean age: 10.9 ± 0.8 years; 10 males and 5 females) were recruited. Performance on a range of standardised academic-related outcome measures was assessed with and without 2.50 D of simulated bilateral hyperopia (administered in a randomised order), before and after 20 minutes of sustained near work, at two separate testing sessions. Academic-related measures included a standardised reading test (the Neale Analysis of Reading Ability), visual information processing tests (Coding and Symbol Search subtests from the Wechsler Intelligence Scale for Children) and a reading-related eye movement test (the Developmental Eye Movement test). Results: Simulated bilateral hyperopia and sustained near work each independently impaired reading, visual information processing and reading-related eye movement performance (p<0.001). A significant interaction was also demonstrated between these factors (p<0.001), with the greatest decrement in performance observed when simulated hyperopia was combined with sustained near work. This combination resulted in performance reductions of between 5% and 24% across the range of academic-related measures. A significant moderate correlation was also found between the change in horizontal near heterophoria and the change in several of the academic-related outcome measures, following the addition of simulated hyperopia. Conclusions: A relatively low level of simulated bilateral hyperopia impaired children’s performance on a range of academic–related outcome measures, with sustained near work further exacerbating this effect. Further investigations are required to determine the impact of correcting low levels of hyperopia on academic performance in children.

Simulated hyperopic anisometropia and reading, visual information processing, and reading-related eye movement performance in children

Purpose: This study investigated the impact of simulated hyperopic anisometropia and sustained near work on performance of academic-related measures in children. Methods: Participants included 16 children (mean age: 11.1 ± 0.8 years) with minimal refractive error. Academic-related outcome measures included a reading test (Neale Analysis of Reading Ability), visual information processing tests (Coding and Symbol Search subtests from the Wechsler Intelligence Scale for Children) and a reading-related eye movement test (Developmental Eye Movement test). Performance was assessed with and without 0.75 D of imposed monocular hyperopic defocus (administered in a randomised order), before and after 20 minutes of sustained near work. Unilateral hyperopic defocus was systematically assigned to either the dominant or non-dominant sighting eye to evaluate the impact of ocular dominance on any performance decrements. Results: Simulated hyperopic anisometropia and sustained near work both independently reduced performance on all of the outcome measures (p<0.001). A significant interaction was also observed between simulated anisometropia and near work (p<0.05), with the greatest decrement in performance observed during simulated anisometropia in combination with sustained near work. Laterality of the refractive error simulation (ocular dominance) did not significantly influence the outcome measures (p>0.05). A reduction of up to 12% in performance was observed across the range of academic-related measures following sustained near work undertaken during the anisometropic simulation. Conclusion: Simulated hyperopic anisometropia significantly impaired academic–related performance, particularly in combination with sustained near work. The impact of uncorrected habitual anisometropia on academic-related performance in children requires further investigation.

Simulated astigmatism impairs academic-related performance in children

Purpose: Astigmatism is an important refractive condition in children. However, the functional impact of uncorrected astigmatism in this population is not well established, particularly with regard to academic performance. This study investigated the impact of simulated bilateral astigmatism on academic-related tasks before and after sustained near work in children. Methods: Twenty visually normal children (mean age: 10.8 ± 0.7 years; 6 males and 14 females) completed a range of standardised academic-related tests with and without 1.50 D of simulated bilateral astigmatism (with both academic-related tests and the visual condition administered in a randomised order). The simulated astigmatism was induced using a positive cylindrical lens while maintaining a plano spherical equivalent. Performance was assessed before and after 20 minutes of sustained near work, during two separate testing sessions. Academic-related measures included a standardised reading test (the Neale Analysis of Reading Ability), visual information processing tests (Coding and Symbol Search subtests from the Wechsler Intelligence Scale for Children) and a reading-related eye movement test (the Developmental Eye Movement test). Each participant was systematically assigned either with-the-rule (WTR, axis 180°) or against-the-rule (ATR, axis 90°) simulated astigmatism to evaluate the influence of axis orientation on any decrements in performance. Results: Reading, visual information processing and reading-related eye movement performance were all significantly impaired by both simulated bilateral astigmatism (p<0.001) and sustained near work (p<0.001), however, there was no significant interaction between these factors (p>0.05). Simulated astigmatism led to a reduction of between 5% and 12% in performance across the academic-related outcome measures, but there was no significant effect of the axis (WTR or ATR) of astigmatism (p>0.05). Conclusion: Simulated bilateral astigmatism impaired children’s performance on a range of academic–related outcome measures irrespective of the orientation of the astigmatism. These findings have implications for the clinical management of non-amblyogenic levels of astigmatism in relation to academic performance in children. Correction of low to moderate levels of astigmatism may improve the functional performance of children in the classroom.

Differential effects of refractive blur on day and night-time driving performance

Purpose To investigate the effect of different levels of refractive blur on real-world driving performance measured under day and nighttime conditions. Methods Participants included 12 visually normal, young adults (mean age = 25.8 ± 5.2 years) who drove an instrumented research vehicle around a 4 km closed road circuit with three different levels of binocular spherical refractive blur (+0.50 diopter sphere [DS], +1.00 DS, +2.00 DS) compared with a baseline condition. The subjects wore optimal spherocylinder correction and the additional blur lenses were mounted in modified full-field goggles; the order of testing of the blur conditions was randomized. Driving performance was assessed in two different sessions under day and nighttime conditions and included measures of road signs recognized, hazard detection and avoidance, gap detection, lane-keeping, sign recognition distance, speed, and time to complete the course. Results Refractive blur and time of day had significant effects on driving performance (P < 0.05), where increasing blur and nighttime driving reduced performance on all driving tasks except gap judgment and lane keeping. There was also a significant interaction between blur and time of day (P < 0.05), such that the effects of blur were exacerbated under nighttime driving conditions; performance differences were evident even for +0.50 DS blur relative to baseline for some measures. Conclusions The effects of blur were greatest under nighttime conditions, even for levels of binocular refractive blur as low as +0.50 DS. These results emphasize the importance of accurate and up-to-date refractive correction of even low levels of refractive error when driving at night.

Academic honors and performance

Despite the social importance of awards, they have been largely disregarded by academic research in economics. This paper investigates whether receiving prestigious academic awards—the John Bates Clark Medal and the Fellowship of the Econometric Society—is associated with higher subsequent research productivity and status compared to a synthetic control group of non-recipient scholars with similar previous research performance. Our results suggest statistically significant positive publication and citation differences after award receipt.

Durability performance of carbon fibre-reinforced polymer strengthened circular hollow steel members under cold weather

The use of circular hollow steel members has attracted a great deal of attention during past few years because of having excellent structural properties, aesthetic appearance, corrosion and fire protection capability. However, no one can deny the structural deficiency of such structures due to reduction of strength when they are exposed to severe environmental conditions such as marine environment, cold and hot weather. Hence strengthening and retrofitting of structural steel members is now very imperative. This paper presents the findings of a research program that was conducted to study the bond durability of carbon fibre-reinforced polymer (CFRP) strengthened steel tubular members under cold weather and tested under four-point bending. Six number of CFRP-strengthened specimens and one unstrengthened specimen were considered in this program. The three specimens having sand blasted surface to be strengthened was pre-treated with MBrace primer and other three were remained untreated and then cured under ambient temperature at least four weeks and cold weather (3 C) for three and six months period of time. Quasi-static tests were then performed on beams to failure under four-point bending. The structural response of each specimen was predicted in terms of failure load, mid-span deflection, composite beam behaviour and failure mode. The research outcomes show that the cold weather immersion had an adverse effect on durability of CFRP-strengthened steel structures. Moreover, the epoxy based adhesion promoter was found to enhance the bond durability in plastic range. The analytical models presented in this study were found to be in good agreement in terms of predicting ultimate load and deflection. Finally, design factors are proposed to address the short-terms durability performance under cold weather.

Destination Brand Performance Measurement Over Time

With increasing investments being made in brand development by destination marketing organisations (DMO) since the 1990s, including rebranding and repositioning, more research is necessary to enhance understanding of how to effectively monitor destination brand performance over time. This chapter summarises key findings from a study of brand performance of a competitive set of destinations, in their most important market, between 2003 and 2012. Brand performance was measured from the perspective of consumer perceptions, based on the concept of consumer-based brand equity (CBBE). The results indicated almost no change in perceptions of the five destinations over the 10-year period. Due to the commonality of challenges faced by DMOs worldwide, it is suggested the CBBE hierarchy provides destination marketers with a practical tool for evaluating brand performance over time; in terms of measures of effectiveness of past marketing communications, as well as indicators of future performance.

A new study on binder performance and formulation modification of anti-corrosive primer based on ethyl silicate resin

Zinc-rich ethyl silicate coatings are quite successful in protecting steel against corrosion under severe exposing conditions. In spite of providing excellent cathodic protection to steel structure after film curing, two-component zinc-rich ethyl silicate coatings have some limitations, one of which is inadequate shelf life as a result of in-can binder gelation. In this work, the preparation steps of ethyl silicate such as pre-hydrolysis, dehydration and organometallic reactions were surveyed and herein an approach towards understanding the cause and effect relationship of the use of ingredients is presented. The effects of water and catalytic acid dosages on gel time under accelerated conditions and the effect of alcoholic solvent order on the rate of the hydrolysis and dehydration reactions were studied via Karl-Fischer test determining the water content of hydrolysate. A thriving optimization in shelf life without any loss in physical–mechanical characteristics of the final film (e.g. hardness, adhesion, solvent and salt spray resistance) was obtained.

Indirect effects of phytochemicals on offspring performance of Queensland fruit fly, Bactrocera tryoni (Diptera: Tephritidae)

Phytochemical lures such as methyl eugenol (ME) and cue-lure are used in the management of Bactrocera fruit flies for monitoring and control. These lures are not just attractants, but also trigger physiological changes in males that lead to enhanced mating success. Additionally, in the cue-lure-responsive Bactrocera tryoni, females mated with lure-fed males exhibit changes in fecundity, remating receptivity and longevity. While the lures show current generation effects, no research has been carried out on possible multigenerational effects, although such effects have been hypothesized within a ‘sexy-son’ sexual selection model. In this study, we test for indirect, cross-generational effects of lure exposure in F1offspring of B. tryoni females mated with cue-lure-fed, zingerone-fed and lure-unfed (=control) males. The F1 attributes we recorded were immature development time, immature survival, adult survival and adult male lure foraging. No significant differences were found between treatments for any of the three life-history measurements, except that the offspring sired by zingerone-fed males had a longer egg development time than cue-lure and control offspring. However, indirect exposure to lures significantly enhanced the lure-foraging ability of F1 adult males. More offspring of cue-lure-fed males arrived at a lure source in both large flight cages and small laboratory cages over a 2-h period than did control males. The offspring of zingerone-fed males were generally intermediate between cue-lure and control offspring. This study provides the first evidence of a next generation effect of fruit fly male lures. While the results of this study support a ‘sexy-son’ sexual selection mechanism for the evolution of lure response in Bactrocera fruit flies, our discussion urges caution in interpreting our results in this way.

A model to estimate the durability performance of both normal and light-weight concrete

There has been an increasing focus on the development of test methods to evaluate the durability performance of concrete. This paper contributes to this focus by presenting a study that evaluates the effect of water accessible porosity and oven-dry unit weight on the resistance of both normal and light-weight concrete to chloride-ion penetration. Based on the experimental results and regression analyses, empirical models are established to correlate the total charge passed and the chloride migration coefficient with the basic properties of concrete such as water accessible porosity, oven dry unit weight, and compressive strength. These equations can be broadly applied to both normal and lightweight aggregate concretes. The model was also validated by an independent set of experimental results from two different concrete mixtures. The model provides a very good estimate on the concrete’s durability performance in respect to the resistance to chloride ion penetration.

Uncertainty quantification applied to the performance analysis of a conical diffuser

This paper offers an uncertainty quantification (UQ) study applied to the performance analysis of the ERCOFTAC conical diffuser. A deterministic CFD solver is coupled with a non-statistical generalised Polynomial Chaos(gPC)representation based on a pseudo-spectral projection method. Such approach has the advantage to not require any modification of the CFD code for the propagation of random disturbances in the aerodynamic field. The stochactic results highlihgt the importance of the inlet velocity uncertainties on the pressure recovery both alone and when coupled with a second uncertain variable. From a theoretical point of view, we investigate the possibility to build our gPC representation on arbitray grid, thus increasing the flexibility of the stochastic framework.

Longitudinal performance of polycaprolactone-based scaffold plus recombinant human morphogenetic protein-2 (rhBMP-2) in large preclinical animal model : 6- versus 12 months

There is strong current interest in the use of biodegradable scaffolds in combination with bone growth factors as a valuable alternative to the current gold standard autograft in spinal fusion surgery Yong et al. (2013). Here we report on 6- vs 12- month data set evaluating the longitudinal performance of a CaP coated polycaprolactone (PCL) scaffold loaded with recombinant human bone morphogenetic protein-2 (rhBMP-2) as a bone graft substitute within a preclinical ovine thoracic spine. The results of this study demonstrate the efficacy of scaffold-based delivery of rhBMP-2 in promoting higher fusion grades at 6- and 12- months in comparison to the scaffold alone or autograft group within the same time frame. Fusion grades achieved at six months using PCL+rhBMP-2 are not significantly increased at twelve months post surgery.

Performance characterisation of a stormwater treatment bioretention basin

Treatment performance of bioretention basins closely depends on hydrologic and hydraulic factors such as rainfall characteristics and inflow and outflow discharges. An in-depth understanding of the influence of these factors on water quality treatment performance can provide important guidance for effective bioretention basin design. In this paper, hydraulic and hydrologic factors impacting pollutant removal by a bioretention basin were assessed under field conditions. Outcomes of the study confirmed that the antecedent dry period plays an important role in influencing treatment performance. A relatively long antecedent dry period reduces nitrite and ammonium concentrations while increasing the nitrate concentration, which confirms that nitrification occurs within the bioretention basin. Additionally, pollutant leaching influences bioretention basin treatment performance, reducing the nutrients removal efficiency, which was lower for high rainfall events. These outcomes will contribute to a greater understanding of the treatment performance of bioretention basins, assisting in the design, operation and maintenance of these systems.

Impact of gender-focused human resource management on performance : the mediating effects of gender diversity

Gender-focused human resource policies and practices signal an organization’s perspective on gender diversity. The signal produces perceptions that the organization values gender diversity leading to a gender-diverse workforce. In turn, a gender-diverse workforce provides a firm with a competitive advantage which should result in higher performance. This paper tests the mediating effects of gender diversity (at non-management and management levels) in the relationship between gender-focused policies and practices and performance. The findings indicate that non-management gender diversity partially mediates the relationship between gender-focused policies and practices and productivity, and management gender diversity partially mediates the relationship between gender-focused policies and practices and perceived market performance. The results have several theoretical, research and practical implications.