Width Of Clear Zone Research Articles

A matched case–control approach to identify the risk factors of fatal pedestrian crashes on a six-lane rural highway in India

Globally, the increase in pedestrian fatalities due to road traffic crashes (RTCs) on transport networks has been a major concern. In low- and middle-income countries (LMICs), pedestrians face a high risk due to RTCs on the rural highway network. The safety evaluation methods, such as observational before-after, empirical Bayes, full Bayes, and cross-sectional methods have been used to identify risk factors of RTCs. However, these methods are data-intensive and have associated limitations. Thus, this study employed a matched case–control method to identify the risk factors of fatal pedestrian crashes. This study utilized crash, traffic volume, speed, geometric, and roadside environment data of a 175 km six-lane rural highway in India. The identified major risk factors, such as clear zone width, the presence of habitation, service roads, and horizontal curve sections, increase the likelihood of a fatal pedestrian crash. This study provides specific insights for modifying the speed limit of highway sections passing through habitation. On such highway sections, designers should shift focus to pedestrian safety. It also suggests that the service road design needs to be reconsidered from a pedestrian safety viewpoint. The proposed method can be used in any other setting having similar traffic and socio-economic conditions.

Effects of design consistency on run-off-road crashes: An application of a Random Parameters Negative Binomial Lindley model

Run-off-road crashes are one of the most common crash types, especially in rural roadway environments contributing significantly to fatalities and severe injuries. These crashes are complex and multi-dimensional events, and factors like road geometry, driver behaviour, traffic characteristics and roadside features contribute to their occurrence, separately or interactively. Sudden changes in road geometry, in particular, can influence driver behaviour, and therefore, in developing a micro-level crash risk model for run-off-road crashes, one of the challenges is incorporating the effects of driver behaviour (disaggregated information) that may arise from the variations in road geometry (aggregated information). This study aims to examine the interaction between road geometry and driver behaviour through a set of measures for design consistency on two-lane rural roads. Multiple data sources, including crash data for 2014–18, traffic data, probe speed data and roadway geometric data, for twenty-three highways in Queensland, Australia, have been fused for this study. Seventeen types of design consistency measures with regard to alignment consistency, operating speed consistency and driving dynamics are tested. A run-off-road crash risk model is estimated by employing the Random Parameters Negative Binomial Lindley regression framework, which accounts for excess zeros in the crash counts and captures the effects of unobserved heterogeneity in the parameter estimates. Results indicate that the geometric design consistency capturing the interaction between driver behaviour and operational factors better predicts run-off-road crashes along rural highways. In addition, roadside attributes like clear zone width, infrastructures, terrain, and roadway remoteness also contribute to run-off-road crashes. The findings of the study provide a comprehensive understanding of the influence of variations in roadway geometry on driver behaviour and run-off-road crashes along rural highways.

A Design Method for the Roadside Clear Zone Based on Accident Simulation Analysis

In order to improve the safety design of roadside areas and reduce the loss of roadside accidents, this paper uses PC-Crash software to perform an accident simulation analysis. By recording the track of the vehicle after entering the roadside, the recommended widths of the roadside clear zone for different operating speeds and horizontal curve radii in straight and curved sections are given. According to our previous research data, the conditions for setting the roadside clear zone are proposed. Finally, based on a cost-benefit ratio analysis, a comprehensive risk index method is adopted to evaluate the social stability risk of the project and conduct research on the design method of the roadside clear zone. The results show that the width of the roadside clear zone has an exponential relation with the departure speed and a power relation with the horizontal curve radius. The research results realize the accurate calculation of the roadside clear zone width and fill in the gaps of the relevant specifications and guidelines in the setting conditions of the roadside clear zone.

Impact of Roadside Design Compliance and Hazard Offset on the Risk of Single-Vehicle, Run-Off-Road Crash Fatalities

Single-vehicle, run-off-road (SVROR) crashes account for a significant portion of all road-related injuries and fatalities worldwide. However, no previous study has examined to what extent roadside design guidelines have been applied, nor (and most importantly) whether having a compliant roadside design reduces the likelihood of fatal injury occurrence in SVROR crashes. Thus, the objectives of this research are i) to examine the level of roadside design compliance within the studied area based on the selected benchmark and ii) to investigate whether roadside design compliance reduces the likelihood of fatal injury occurrence in SVROR crashes. Findings from this study are based on extensive crash and field data collected from 1,070 SVROR injury collisions and locations, respectively. The study shows that i) only 32 percent of the studied locations contained compliant design, and ii) barrier and discrete-obstacle lateral offsets larger than 6 and 12 meters, respectively, tended to lower fatality risk. The 12-meter clear-zone (CZ) width is larger than that recommended by previous research, which has based CZ width recommendations also on cost-benefit procedures and not just on fatality risk reduction.

Calculation of the Roadside Clear Zone Width along Highways Based on the Safe Slope

International crash data indicate that roadside characteristics contribute to more than half of all roadside accidents involving serious injury or death. Therefore, research on roadside safety is urgently needed. Based on the vehicle departure speed, pavement height (i.e., the difference between pavement elevation and ground elevation), slope gradient, and horizontal curve radius, this study uses PC-Crash simulation software to carry out tests of trucks and cars exiting a road. A chi-squared automatic interaction detection (CHAID) decision tree is used to explore the causative mechanism of vehicle rollover, and the concept of a “safe slope” to ensure that vehicles do not roll over is proposed. Aiming at straight and curved sections, discriminant functions of vehicle rollover and nonrollover are fitted through Bayesian discriminant analysis, and safe slope calculation models for trucks and cars are then constructed. Based on the obtained safe slope models, calculation methods for the safe slope and the roadside clear zone width involving different traffic compositions are proposed by calibrating the lateral distance from the final position of nonrollover vehicles to the road edge. The results show that the factors affecting vehicle rollover are, in descending order of importance, the slope gradient, pavement height, vehicle type, departure speed, and horizontal curve radius. For a section with a large proportion of cars, the slope gradient should not be steeper than 1:3.5. The horizontal curve radius should not be less than 600 m for a section with a large proportion of trucks and a slope gradient steeper than 1:3.5 or shallower than 1:2.5. Additionally, for a section with a pavement higher than 0.5 m and a slope gradient steeper than 1:2.5, the operating speed limit should be lower than 60 km/h. These research results have theoretical value and practical significance to improve the driving safety level and reducing the risk of roadside accidents.

ANTI-MICROBIAL ACTIVITY OF GINGER FLOWER AGAINST SOME CAUSATIVE AGENT OF ACUTE RESPIRATORY INFECTION

Various microorganisms such as Streptococcus pneumonia, Haemophilus influenza, Chlamydia spp, and Mycoplasma pneumonia can cause ARI. The ginger flower which contains various phytochemicals that have potential anti-microbial. Recent study was aimed to explore the anti-microbial properties of ginger flower extract. This study was experimental in vitro study with the disc diffusion method. The ethanol extract of Ginger flowers was obtained by maceration method with a ratio of Simplicia to solvent 1:10. Then it concentrated with a rotary evaporator. The ethanol extract of the ginger flower was diluted by DMSO into four concentrations viz. 100%, 75%, 50%, and 25%. The anti-microbial activity assay used three different types of microbes (Streptococcus pneumonia, Haemophilus influenza, and Candida albicans) different in 3 repetitions. There were significant differences each concentration on the width of clear zone among Streptococcus pneumonia (P-value = 0.010), Haemophilus influenza (P-value = 0.011), and Candida albicans (P-value = 0.005). Also, all concentrations of ginger flower extract showed no significant difference between positive controls; however, significant differences were found for negative controls. Hence, It can be concluded that 25% of ginger flower extract has been sufficient to inhibit the growth of various tested microorganisms.

Fabrication and physicochemical assessment of L-Histidine cross-linked PVA/CMC bio-composite membranes for antibacterial and food-packaging applications

ABSTRACT The intention of this study was to prepare polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) films and to improve their physicochemical properties by cross-linked with amino acids. Thus, the bio-composite films/membranes of PVA/CMC were an amalgamation with L- Histidine as the crosslinker via solution casting scheme. The effect of the L-Histidine addition on blend films was explored by various physio-chemical characterisation techniques. The contact angle assessment of the as-prepared film have remained increased (47.31, 50.42, and 58.09) by the addition of L-Histidine content. The antibacterial activity was tried against certain food pathogenic bacteria. To the extent of the clear zone width of the E. coli and B. cereus bacteria were included per filmstrips and the values of which remained constantly higher than the width of assumed films. Largely, the L-Histidine cross-linked PVA/CMC film happens to be a suitable material for an antibacterial agent and food-packaging applications.

Potention of Antibacterial Isolat Actinomycetes to Proteolitic and Amilolitic Activity Escherichia Coli ATTC 25922

Occurs E. coli resistance to class 3 cephalosporin class antibiotics and fluoroquinolone groups. The antibiotic resistance that occurs has narrowed the choice of therapy. This study aims to determine the effect of Actinomycetes isolates on proteolytic and amylolytic enzymes E. coli ATCC 25922. This research is experimental research, qualitative tests of protease and amylase enzymes from E. coli ATCC 25922 shown by clear zones around the growing colonies. The result of ANOVA One-Way test showed a significant difference in the width of clear zone, colony zone and PER and AER score with p-value < 0,05. This indicates that Actinomycetes isolates contain compounds that can act as inhibitors of protease and amylase enzymes from E.coli ATCC 25922. It is hoped that there will be research about the identification of Actinomycetes species isolates in Bogor Botanical Garden so that later can be cultivated and produced as an antibiotics alternative.

A green in situ synthesis of silver nanoparticles on cotton fabrics using Aloe vera leaf extraction for durable ultraviolet protection and antibacterial activity

This study presented a simple and environmentally friendly method of in situ synthesis of silver nanoparticles (AgNPs) on cotton fabrics for durable ultraviolet (UV) protection and antibacterial activity using Aloe vera leaf extraction (AVE) as a reducing and stabilizing agent. Cotton fabrics were pretreated in water, and then immersed in AgNO3 and AVE, respectively. Cotton fabrics were characterized by small angle X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis, UV protection, antibacterial activity, and laundering durability. Comparing with the smooth surface of the control cotton fabric, SEM and energy dispersive X-ray spectrometry (EDX) results showed that there were a considerable number of Ag2O and AgNPs loading on the surface of the pretreated and Ag loaded cotton fabrics. The XRD pattern indicated, respectively, the existence of Ag2O and AgNPs, the structures of which were similar to JCPDS File No.65-3289 and JCPDS File No. 01-071-4613 on the pretreated and Ag loaded cotton fabrics. The pretreated and Ag loaded cotton fabrics showed excellent UV protection, antibacterial activity, and laundering durability, especially the Ag loaded cotton fabric, of which the UV protection factor value and transmission of UVA were 148 and 1.11%, respectively, after 20 washing cycles, and the clear zone width was more than 4 mm against E. coli or S. aureus. AgNPs facilitated the improvement of the thermal property of the cotton fabrics. Thus this facile in situ reduction of AgNPs with AVE may bring a promising and green strategy to produce functional textiles.

Evaluating the effect of vegetation and clear zone width on driver behavior using a driving simulator

Roadside vegetation provides a myriad of environmental and psychological benefits to drivers. While research has shown that natural landscapes cause less stress and frustration to the driver among other benefits, the same vegetation may potentially increase the severity of run-off-the-road crashes. The aim of this study was to evaluate the extent to which clear zone width and roadside vegetation density influence operating speeds and lateral positioning to determine whether the roadside environment has any effect on drivers’ attention to their speed. A within subject driving simulator experiment tested six combinations of clear zone widths and roadside vegetation densities. Participants’ driving performance was measured throughout the virtual drive. Along tangents and curves to the left, participants slowed down and drove closer to the centerline when trees were near the edge of the road. Similar to the results reported in Calvi (2015), no statistically significant differences in operating speeds were observed with change in vegetation density. The analysis of drivers’ eye movements indicated that the roadside configuration did not affect participants’ attention to their operating speed, however, the number of glances was highly correlated to the time spent in the virtual drive. The results provide evidence to suggest that, while the increased roadside vegetation density does not necessarily result in reduced driver speeds or deviated lateral positioning, the manipulation of the roadside clear zone width does provide tangible benefits to safe driver behavior. These research findings should be considered in the design of roadside elements, accounting for overstated benefits to roadside vegetation.

Evaluating the safety risk of roadside features for rural two-lane roads using reliability analysis

The severity of roadway departure crashes mainly depends on the roadside features, including the sideslope, fixed-object density, offset from fixed objects, and shoulder width. Common engineering countermeasures to improve roadside safety include: cross section improvements, hazard removal or modification, and delineation. It is not always feasible to maintain an object-free and smooth roadside clear zone as recommended in design guidelines. Currently, clear zone width and sideslope are used to determine roadside hazard ratings (RHRs) to quantify the roadside safety of rural two-lane roadways on a seven-point pictorial scale. Since these two variables are continuous and can be treated as random, probabilistic analysis can be applied as an alternative method to address existing uncertainties. Specifically, using reliability analysis, it is possible to quantify roadside safety levels by treating the clear zone width and sideslope as two continuous, rather than discrete, variables. The objective of this manuscript is to present a new approach for defining the reliability index for measuring roadside safety on rural two-lane roads. To evaluate the proposed approach, we gathered five years (2009–2013) of Illinois run-off-road (ROR) crash data and identified the roadside features (i.e., clear zone widths and sideslopes) of 4500 300ft roadway segments. Based on the obtained results, we confirm that reliability indices can serve as indicators to gauge safety levels, such that the greater the reliability index value, the lower the ROR crash rate.

EFFECT OF DIFFERENT LIGHTING CONDITIONS ON FEEDING ACTIVITY AND EYE ADAPTATION OF POST LARVAE PENAEUS VANNAMEI

This study was conducted to investigate the effect of light and dark conditions on feeding activity and eye adaptations of post larvae (PL5, PL10, PL20 and PL30) Penaeus vannamei fed with frozen Artemia. Shrimp PL were placed individually in beakers and after acclimatization under the light or dark condition, PL were left to ingest known number of Artemia for 30 minutes. Thereafter, each PL was subsequently anesthetized by putting an ice cube into the beakers followed by adding few drops of paraformaldehyde. The results showed that the PL5 ingested significantly more frozen Artemia under light condition compared to dark condition (P<0.05). The eye structures of PL5 comprises of crystalline cone, rhabdom and fasciculated zone. However, it was incomplete due to the lack of clear zone and no migration of the screening pigment granules was observed under light and dark conditions. On the contrary, the number of frozen Artemia ingested by the latter stages PL10, PL20 and PL30 showed no significant differences (P>0.05) under both light conditions and these PL have complete eye structures with define clear zone. The width of clear zone was found to increase proportionally with the growth of the PL. Besides that, the screening pigment granules were able to migrate under light and dark conditions. The ability of the PL10, PL20 and PL30 to ingest almost similar numbers of Artemia under light and dark conditions suggests that different lighting conditions did not affect the feeding activity of the PL and other sensory organs may play roles in detecting food, while PL5 need light to improve their feeding activity. Based on these results, we suggest that in aquaculture practice, during the rearing of early stage of PL (<PL5), a brighter environment or light should be provided to enhance larval feeding activities. Whereas, later stages of PL (>PL10) can be cultured under any light condition.

Effectiveness of cable barriers, guardrails, and concrete barrier walls in reducing the risk of injury

Roadway departure crashes tend to be severe, especially when the roadside exposes the occupants of errant vehicles to excessive injury hazards. As a cost-effective method when the clear zone width is insufficient, road barriers are often installed to prevent errant vehicles from colliding with dangerous obstacles or traversing steep slopes. This paper focuses on the safety performance of road barriers in Indiana in reducing the risk of injury. The objective of the study presented here is to compare the risk of injury among different hazardous events faced by an occupant in a single-vehicle crash. The studied hazardous events include rolling over, striking three types of barriers (guardrails, concrete barrier walls, and cable barriers) with different barrier offsets to the edge of the travelled way, and striking various roadside objects.A total of 2124 single-vehicle crashes (3257 occupants) that occurred between 2008 and 2012 on 517 pair-matched homogeneous barrier and non-barrier segments were analyzed. A binary logistic regression model with mixed effects was estimated for vehicle occupants. The segment pairing process and the use of random effects were able to handle the commonality within the same segment pair as well as the heterogeneity across segment pairs.The modeling results revealed that hitting a barrier is associated with lower risk of injury than a high-hazard event (hitting a pole, rollover, etc.). The odds of injury are reduced by 39% for median concrete barrier walls offset 15–18ft from the travelled way, reduced by 65% for a guardrail face offset 5–55ft, reduced by 85% for near-side median cable barriers (offset between 10ft and 29ft), and reduced by 78% with far-side median cable barriers (offset at least 30ft). Comparing different types of barriers is useful where some types of barriers can be used alternatively. This study found that the odds of injury are 43% lower when striking a guardrail instead of a median concrete barrier offset 15–18ft and 65% lower when striking a median concrete barrier offset 7–14ft. The odds of injury when striking a near-side median cable barrier is 57% lower than the odds for a guardrail face. This reduction for a far side median cable barrier is 37%. Thus, a guardrail should be preferred over a concrete wall and a cable barrier should be preferred over a guardrail where the road and traffic conditions allow. In the light of the results, installing median cable barriers on both sides of the median to reduce their lateral offset is beneficial for safety.The study also found that the unexplained heterogeneity across vehicles is much larger than it was across matched segment pairs.

A Study on the Widths Design of Highway Roadside Clear Zone by Considering Multi-factors

This paper analyses the clear zone design parameters, including driver reaction time, conditions of vehicle leaving roadway and driving distance in clear zone. Meanwhile, in classical physics, the process that the vehicle runs off roadway can be seen as a combination of uniform motion in a straight line and rectilinear motion of uniform deceleration. Then, based on the forgiving design concept, the paper sets up a calculation model for the roadside clear zone. It calculates width range of roadside clear zone. According to the calculated results and the actual instance of roadside, it brings forward the recommended width of roadside clear zone. Compared with RISER (Roadside Infrastructure for Safer European Roads), the paper considers driver reaction time, so the calculation of clear zone width is larger and safer. However, the computed results are reasonable and acceptable because they are essentially consistent with the suggested clear zone distance in AASHTO's Roadside Design Guide (American Association of State Highway and Transportation Officials). Therefore, the research results of the paper could be a supplementary guidance or reference for road designer and administrator.

Comparative Study of Extracts from Rhubarb on Anti-Thrombotic and Anti-Platelet Activity

ABSTRACT Objective : The purpose of this study is to compare anti-thrombotic activities of 4 Rhubarb species.Methods : Rhubarb has been used as medical and edible resources worldwide for the therapy of cancer, constipation and inflammation, etc. To compare the anti-thrombotic activities among the species within rhubarb, we investigated and compared the inhibitory properties of water extracts from R. palmatum(RPE), R. officinale(ROE), R. nobile(RNE), and R. franzenbachii(RFE) on the fibrinolysis, blood coagulation and platelet aggregation. APTT and PT, blood coagulation time, were measured by apparatus of auto blood coagulation analysis that called ACL-7000. The measurement of fibrinolysis was measured and compares with the width of clear zone from melted fibrin plate. The platelet aggregation w as measured and compared with inhibition rate of aggregation.Results : We found out the best species from rhubarb showing the signifi cant fibrinolytic, anti-coagulant and anti-platelet aggregation activity. Our results show that Rheum nobile (RNE) has the most effective anti-thrombotic activity among 4 tested rhubarb.Conclusions : This study, therefore, RNE will be able to be used the development of drug which is thrombosis treatment.Key Words : Anti-Thrombotic; Platelet Aggregation; Rheum palmatum; Rheum officinale; Rheum nobile; Rheum franzenbachii

Safety and cost-effectiveness of clear zones in Iran

This paper examines different clear-zone improvement alternatives in rock cuts, and compares the likely effect on safety and construction costs. Where a roadway passes through rock cuts, the construction cost of providing the clear zone is very high. This paper is based on research that demonstrates a method for selecting the appropriate clear zone in rural two-lane highways in Iran based on the site and traffic conditions expected at the site. A method is described for determining the rock-cut width that best balances the cost of construction with the improvements in safety that would result from a wider clear zone in the rock cut. The objective of this study is to quantify the societal cost of rock-face accidents, so that the costs and benefits associated with different clear-zone policies can be explicitly addressed during the preliminary design process. This study shows that the need for extra clear-zone width in steep and bendy routes (specially with external curves of less than 195 m radius) is more critical than that for straight and level ones. The existence of external horizontal curves simultaneously with severe longitudinal slopes increases the probability of vehicles’ encroachment by as much as eight times in comparison with straight and level routes. An interesting point to note is that, by providing wider lanes, the need for extra clear-zone width is reduced dramatically.

The Effects of the Soils on the Antibacterial Activity of the Commercial Anticrobial Treatment Socks

This paper describes the effects of varicts soils on the antibacterial activity of antibacterial agents in the commercial anticrobial treatment socks. In this paper, we deals with six types of soils (Japanese sake, sause, soy sause, milk, juice and miso soup) and make a wear test, and examines the change of the antibacterial activity of socks contaminated with various soils.The results obtained are as follows.(1) When the commercial anticrobial treatment socks were contaminated with soils artificially, the inhibition percenage decreased than the socks with no soils. But, inhibition percntage increased again after washing and removing the soils. It was recognized positive correlation between the reflectnace of socks contaminated with soils and the inhibition percentage. This tendency was similar when the socks were washed after three days. When the socks were washed after one month, however, the recovery of the inhibition percentage was not recognized, because the soils contaminated was not removed easily.(2) In the case of wear test, the width of clear zone of the socks weared was smaller than the no-wear socks, and the antibacterial activity of the socks weared decreased. This result shows that the growth of microorganisms becomes actively when the soils were adhered even if the antibacterial agents was not removed by washing operation. It was recognized the negative correlation between the number of bacteria and each component of soils, and the coefficient of correlation of untreated socks was higher than the commercial anticrobial treatment socks. Because, the bacteria adhated to the commercial anticrobial treatment socks were killed or inhibitioned by the antibacterial agents.When the textile product was contaminated with soils, there was a remarkable growth of microorganisms. Therefore, it was necessary to remove immediately the soils by washing even if the socks was treated by the anticrobial treatment.

Effects of Surface Active Agents and Builders on Fastness to Washing of Antibacterial Agents in the Latest Commercial Anticrobial Treatment Products

This paper describes the effects of surface active agent and builder on the fastness to washing of antibacterial agents in commercial anticrobial treatment products.The results obtained are as follows. (1) With regard to the effects of detergents on the fastness to washing of antibacterial agents, the antibacterial activity to Staphylococcus aureus IFO 3060 with sample No. 1 was large in the order of : washing with water, light duty detergent, liquid detergent, soap powder, according to inclinations of each regression curves. Because the width of clear zone when washed with detergent having high concentration of surface active agents is smallas shown in the results of antibacterial activity test. negative correlation was recognized between the concentration of surface active agents in detergents and the inhibition percent. This tendency was similer to other three test organisms. (2) With regard to the effects of the kind of surface active agent on the fastness to washing of antibacterial agents, the antibacterial activity to three test organisms with sample No. 2 was small in the order of : marseies soap, soap, AOS, AES, LAS, control washing with water. Furthermore, the builder also influences the antibacterial activity, the degree of the effect on the antibacterial activity was lager sodium tripolyphosphate than sodium silicate. And the additive effects by combining the surface active agent with the builder were recognized .As the antibacterial activity of antibacterial agents in commercial anticrobial treatment products, therefore, is lost rapidly by washing with the detergents having high concentration of surface active agents, such as soap powder, it is necessary to use the detergents having low concentration of surface active agents and builders to keep the antibacterial and antifungal activities of antibacterial angents.

Image quality and acceptance angle in a reflecting superposition eye

1. Intracellular recordings of acceptance angles were made at different adaptation states and at different times of day, from retinula cells in the central region of the reflecting superposition eye of the freshwater crayfish,Cherax destructor (Clark 1936). A number of cells were held for longer than 24 h. 2. The acceptance angle is greater in the dark-adapted (DA) state than in the light-adapted (LA) state, but this difference is significantly smaller at night than during the day. Mean values were 5 ° (LA day and night), 19 ° (DA day) and 13 ° (DA night). 3. The anatomy was studied with proper attention to the time of day. Light microscopy shows that there is an increase of 10–15% in the clear-zone width in the DA state at night compared to the other states. This is achieved by a proximal movement of the rhabdom layer. 4. The position of the distal screening pigment depends on the ambient light level. It is around the distal cones in the dark and moves into the clear zone on light-adaptation. The proximal screening pigment, however, attains only the first stage of dark-adaptation (Frixione et al. 1979) during the day. Complete dark-adaptation (movement below the basement membrane) occurs only at night. The distal reflecting pigment remains around the cones at all times, and the proximal reflecting pigment forms a cup around the base of the rhabdom during both day and night. 5. The smaller acceptance angle in the DA state at night, compared to that of the DA day state, indicates that the receptors lie closer to the best superposition focus in this state, when the animal is in air. 6. The effect of the change in clear-zone width and the performance of the eye in air and under-water are examined using a model of the eye.