Errors in young children's decisions about traffic gaps : experiments with roadside simulations

Young children's vulnerability as pedestrians has often been attributed to deficiencies in their decision making about vehicle approach times. Some studies have found a preponderance o f risky decisions below the age of eight years. In contrast, studies using a closer simulation of road crossing, known as the pretend road, have found a preponderance of overcautious decisions in young children: traffic gaps of adequate size were frequently rejected (missed opportunities). However, the pretend road has potentially distorting characteristics which may account for this divergent pattern of findings. The experiments reported below show that new simulations that eradicate distortions nevertheless validate the pattern of results produced with the pretend road. Differences between adults and young children were pronounced for missed opportunities, but not for risky decisions. Subsidiary analyses suggest that the risky decisions of the youngest children may have arisen through lapses in attention, rather than deficits in timing. These findings run contrary to the view that attributes young children's pedestrian vulnerability to perceptuo-motor deficiency

Behavioural group training of children to find safe routes to cross the road

Young children show poor judgement when asked to select safe places to cross the road and frequently consider dangerous sites to be safe ones. Thus, a sharp bend, the brow of a hill or positions close to parked cars are considered safe places to cross by most children under 9 years of age. This study examined the effectiveness of two practical training programmes in improving the judgements of 5-year-olds. Children were trained in small groups either in the real road environment or using simulations set up on a table-top model. A series of pre-and post-tests allowed the effectiveness of training to be assessed. Significant improvements relative to controls were found in both groups following training. There were no differences between the two training methods. Improvements were robust and no deterioration was observed two months after the programme ended. However, the benefits of group training were less marked than in an earlier study in which children were trained individually. The implications for road safety education are discussed

A developmental and training study of children's ability to find safe routes to cross the road

The sites and routes that children of different ages considered to be safe to cross the road were investigated. In Expt 1, children aged 5, 7, 9 and 11 years were instructed to choose 'the safest' crossing sites and routes to specified destinations. The results showed a gradual developmental shift with safer, more adult-like choices appearing with increasing age. Five and 7 year olds exhibited only a rudimentary selection procedure, choosing the most direct route as safest and showing a marked lack of awareness of the dangers posed by nearby roadside obstacles or other visual restrictions. In a further experiment, 5-year-olds were individually trained in finding safe places to cross. Training took place either in the real road environment or using a tabletop model of a traffic environment. A series of pre-and post-tests enabled the effectiveness of the training to be assessed. Substantial improvements following training were obtained in both groups. No differences were found between the two training methods. Though performance fell somewhat over the two months following training, trained children still outperformed their untrained peers eight months after the programme ended. The implications for road safety education are discussed

The effectiveness of parents in promoting the development of road crossing skills in young children

Young children show poor judgment when asked to select a safe place to cross the road, frequently considering dangerous sites to be safe. Correspondingly, child pedestrian accidents are over-represented at such locations. Increasing the child's ability to recognise such dangers is a central challenge for road safety education. Practical training methods have proved effective in improving such judgments but are labour-intensive, time-consuming and therefore difficult to implement on a realistic scale. The study examined the possibility that volunteers from the local community might be capable of using such methods to promote children's pedestrian competence. Sixty children from the Primary 1 (Reception) classes of three Glasgow schools took part. Volunteers were ordinary parents from the same areas. None had 'formal' experience of working with children other than through being parents. Method. Volunteers received experience of training children at courses organised in each school. Children learned in small groups, receiving two sessions of roadside training followed by four on a table-top model. Pre- and post-tests allowed the effectiveness of training to be assessed. Significant improvements relative to controls were found in all children following training. Improvements proved robust and no deterioration was observed two months after the programme ended. Comparison with a previous study in which training was undertaken by highly qualified staff showed that the volunteers were as effective as 'expert' trainers. Parent volunteers can significantly increase the pedestrian competence of children as young as five years. They constitute a most valuable 'resource' in road safety education. The opportunities afforded by involving the local community in educational interventions should be further explored

Coupling 2-D cylindrical and 3-D x-y-z transport computations

This paper describes a new two-dimensional (2-D) cylindrical geometry to three-dimensional (3-D) rectangular x-y-z splice option for multi-dimensional discrete ordinates solutions to the neutron (photon) transport equation. Of particular interest are the simple transformations developed and applied in order to carry out the required spatial and angular interpolations. The spatial interpolations are linear and equivalent to those applied elsewhere. The angular interpolations are based on a high order spherical harmonics representation of the angular flux. Advantages of the current angular interpolations over previous work are discussed. An application to an intricate streaming problem is provided to demonstrate the advantages of the new method for efficient and accurate prediction of particle behavior in complex geometries

Stable Carbon and Nitrogen Isotopes in a Peat Profile Are Influenced by Early Stage Diagenesis and Changes in Atmospheric CO2 and N Deposition

In this study, we test whether the δ13C and δ15N in a peat profile are, respectively, linked to the recent dilution of atmospheric δ13CO2 caused by increased fossil fuel combustion and changes in atmospheric δ15N deposition. We analysed bulk peat and Sphagnum fuscum branch C and N concentrations and bulk peat, S. fuscum branch and Andromeda polifolia leaf δ13C and δ15N from a 30-cm hummock-like peat profile from an Aapa mire in northern Finland. Statistically significant correlations were found between the dilution of atmospheric δ13CO2 and bulk peat δ13C, as well as between historically increasing wet N deposition and bulk peat δ15N. However, these correlations may be affected by early stage kinetic fractionation during decomposition and possibly other processes. We conclude that bulk peat stable carbon and nitrogen isotope ratios may reflect the dilution of atmospheric δ13CO2 and the changes in δ15N deposition, but probably also reflect the effects of early stage kinetic fractionation during diagenesis. This needs to be taken into account when interpreting palaeodata. There is a need for further studies of δ15N profiles in sufficiently old dated cores from sites with different rates of decomposition: These would facilitate more reliable separation of depositional δ15N from patterns caused by other processes

The granite‑hosted Variscan gold deposit from Santo António mine in the Iberian Massif (Penedono, NW Portugal): constraints from mineral chemistry, fuid inclusions, sulfur and noble gases isotopes

The study area is located in the Central Iberian Zone, a major tectonic unit of the Iberian Massif (Variscan belt). In this region the basement is composed of Cambrian-Ordovician sedimentary and minor volcanic rocks that underwent deformation and metamorphism during the Carboniferous. These metamorphic rocks host ca. 331–308 Ma granitic plutons emplaced during the D2 extensional and D3–D4 contractional deformation phases. The gold-bearing quartz veins from the Santo António mine (Penedono region) occur in granite formed at 310.1 ± 1.1 Ma and post-dated the peak of metamorphism. Gold–silver alloy is included in quartz, but mainly occurs in spaces between grains or micro-fractures within arsenopyrite of all three generations and less in pyrite. Late sulphides and sulphosalts were deposited along fractures mainly in arsenopyrite, and locally surrounding the gold–silver alloy grains. Ferberite, scheelite and stolzite replace arsenopyrite. The abundant aqueous carbonic fluids and the occurrence of a low-salinity fluid and their minimum possible entrapment temperature of 360–380 °C suggest that this gold-forming event began during the waning stages of the Variscan orogeny. The mean δ34S values of arsenopyrite and pyrite are − 4.7‰ and − 3.8‰, respectively. He–Ar–Ne isotopic data suggest a crustal origin. The ascent of the granite magma has provided the heat for remobilization of gold, other metals and metalloids from the metamorphic rocks. This gold-arsenopyrite deposit has thus similar characteristics as other selected gold-arsenopyrite deposits from the Iberian Massif, but it contains tungstates.El área de estudio está ubicada en la Zona Centroibérica, una importante unidad tectónica del Macizo Ibérico (cinturón varisco). En esta región el basamento está compuesto por rocas sedimentarias y volcánicas del Cámbrico-Ordovícico tectonizadas y metamorfzadas durante el Carbonífero. Estas rocas metamórfcas sirven como caja de los plutones graníticos datados en torno a 331–308 Ma y que fueron emplazados durante la fase de deformación extensional D2 y las fases de deformación contraccional D3 y D4. Las venas de cuarzo ricas en oro de la mina de Santo António (región de Penedono) que aparecen en un granito datado a los 310.1 ± 1.1 Ma son posteriores al pico metamórfco regional. La aleación de oro y plata se incluye en el cuarzo, pero se produce principalmente en los espacios entre granos o micro-fracturas dentro de arsenopirita de las tres generaciones y menos en pirita. Los sulfuros y sulfuros tardíos se depositaron a lo largo de las fracturas principalmente en arsenopirita, y alrededor de los granos de aleación de oro y plata. Ferberita, scheelita y la estolzita sustituyen a la arsenopirita. Los abundantes líquidos acuosos carbónicos y la presencia de un fuido de baja salinidad y su posible temperatura de atrapamiento mínima en torno de 360-380 ºC sugieren que este evento de formación de oro comenzó durante las etapas fnales de la orogenia varisca. Los valores medios de S de arsenopirita y pirita son − 4.7 ‰ y − 3.8 ‰, respectivamente. Los datos isotópicos de He–Ar–Ne sugieren que en el origen de los fuidos mineralizados participa la corteza continental. El ascenso del magma granítico ha provisto el calor para la movilización del oro, otros metales y metaloides desde las rocas metamórfcas. Este depósito de oroarsenopirita tiene así características similares a otros yaciamientos con arsenopirita y oro del Macizo Ibérico, pero sin embargo contienen tungstates.This research was financially supported by Fundação para a Ciência e Tecnologia through the projects GOLDGranites, Orogenesis, Long-term strain/stress and Deposition of ore metals—PTDC/GEO-GEO/2446/2012: COMPETE: FCOMP-01-0124-FEDER-029192 and UID/GEO/04035/2013

Developing attentional control in naturalistic dynamic road crossing situations

In the last 20 years, there has been increasing interest in studying visual attentional processes under more natural conditions. In the present study, we propose to determine the critical age at which children show similar to adult performance and attentional control in a visually guided task; in a naturalistic dynamic and socially relevant context: road crossing. We monitored visual exploration and crossing decisions in adults and children aged between 5 and 15 while they watched road trafc videos containing a range of trafc densities with or without pedestrians. 5–10 year old (y/o) children showed less systematic gaze patterns. More specifcally, adults and 11–15y/o children look mainly at the vehicles’ appearing point, which is an optimal location to sample diagnostic information for the task. In contrast, 5–10y/os look more at socially relevant stimuli and attend to moving vehicles further down the trajectory when the trafc density is high. Critically, 5-10y/o children also make an increased number of crossing decisions compared to 11–15y/os and adults. Our fndings reveal a critical shift around 10y/o in attentional control and crossing decisions in a road crossing task