Effect of field of view and monocular viewing on angular size judgements in an outdoor scene

Observers typically overestimate the angular size of distant objects. Significantly, overestimations are greater in outdoor settings than in aircraft visual-scene simulators. The effect of field of view and monocular and binocular viewing conditions on angular size estimation in an outdoor field was examined. Subjects adjusted the size of a variable triangle to match the angular size of a standard triangle set at three greater distances. Goggles were used to vary the field of view from 11.5 deg to 90 deg for both monocular and binocular viewing. In addition, an unrestricted monocular and binocular viewing condition was used. It is concluded that neither restricted fields of view similar to those present in visual simulators nor the restriction of monocular viewing causes a significant loss in depth perception in outdoor settings. Thus, neither factor should significantly affect the depth realism of visual simulators

Determination of the radionuclide content of feces and urine from astronauts engaged in space flight

Measurement of radiation exposure of Apollo 7, 8, 9, and 10 astronauts by determination of radionuclide content of feces and urin

Some implications of sampling choices on comparisons between satellite and model aerosol optical depth fields

The comparison of satellite and model aerosol optical depth (AOD) fields provides useful information on the strengths and weaknesses of both. However, the sampling of satellite and models is very different and some subjective decisions about data selection and aggregation must be made in order to perform such comparisons. This work examines some implications of these decisions, using GlobAerosol AOD retrievals at 550 nm from Advanced Along-Track Scanning Radiometer (AATSR) measurements, and aerosol fields from the GEOS-Chem chemistry transport model. It is recommended to sample the model only where the satellite flies over on a particular day; neglecting this can cause regional differences in model AOD of up to 0.1 on monthly and annual timescales. The comparison is observed to depend strongly upon thresholds for sparsity of satellite retrievals in the model grid cells. Requiring at least 25% coverage of the model grid cell by satellite data decreases the observed difference between the two by approximately half over land. The impact over ocean is smaller. In both model and satellite datasets, there is an anticorrelation between the proportion <i>p</i> of a model grid cell covered by satellite retrievals and the AOD. This is attributed to small <i>p</i> typically occuring due to high cloud cover and lower AODs being found in large clear-sky regions. Daily median AATSR AODs were found to be closer to GEOS-Chem AODs than daily means (with the root mean squared difference being approximately 0.05 smaller). This is due to the decreased sensitivity of medians to outliers such as cloud-contaminated retrievals, or aerosol point sources not included in the model

The narrative coherence of witness transcripts in children on the autism spectrum

Background and Aims. Autistic children often recall fewer details about witnessed events than typically developing children (of comparable age and ability), although the information they recall is generally no less accurate. Previous research has not examined the narrative coherence of such accounts, despite higher quality narratives potentially being perceived more favourably by criminal justice professionals and juries. This study compared the narrative coherence of witness transcripts produced by autistic and typically developing (TD) children (ages 6-11 years, IQs 70+). Methods and Procedures. Secondary analysis was carried out on interview transcripts from a subset of 104 participants (autism=52, TD=52) who had taken part in a larger study of eyewitness skills in autistic and TD children. Groups were matched on chronological age, IQ and receptive language ability. Coding frameworks were adopted from existing narrative research, featuring elements of ‘story grammar’. Outcomes and Results. Whilst fewer event details were reported by autistic children, there were no group differences in narrative coherence (number and diversity of ‘story grammar’ elements used), narrative length or semantic diversity. Conclusions and Implications. These findings suggest that the narrative coherence of autistic children’s witness accounts is equivalent to TD peers of comparable age and ability

Guidance, Flight Mechanics and Trajectory Optimization. Volume 5 - State Determination And/or Estimation

Guidance, flight mechanics, and trajectory optimizatio

Pulping characteristics of Pinus caribaea from Fiji: The effect of rate of growth

Samples of Pinus caribaea Mor. var hondurensis Barr. and Golf. from Drasa and Seaqaqa in Fiji were sub-divided so that they represented the fastest and slowest growth rate on each site. It was found that the fast growing trees yielded approximately twice the volume of wood yielded by the slow growing trees. There were no significant differences in apparent wood density or chemical composition, in pulp yield or ease of digestion by the sulphate process or in the characteristics of the unbleached pulp. In the absence of better information on which to base a selection programme, the limited evidence of this trial indicates that the best policy for the forester producing pulp wood is to adopt methods and to make selections to obtain high volume production

Pulping characteristics of three trees of Pinus caribaea with different densities grown in Jamaica

The pulping characteristics of three trees of Pinus caribaea var hondurensis with different densities grown in Jamaica were determined using the sulphate method. Ten trees, ten years old, had been selected at random from a single plantation in Jamaica and the first, fifth and ninth in order of density were pulped to assess the differences in pulping characteristics that might be due to density. Two digestions, one with 17.5% active alkali, one with 20% were made on each tree using otherwise identical conditions. At both alkali doses yields of pulp increased with increasing density of the wood and, unexpectedly, the Kappa numbers of the pulps from the medium density wood were higher than those of either of the others. The breaking lengths and bursting strengths decreased and the bulk increased with increasing density. When compared at equal digestion conditions, the tearing strengths increased but to a peak with medium density. This was influenced by the higher Kappa numbers of the pulps from medium density wood and, when compared at equal Kappa numbers, the tearing strength showed a marked increase as the wood density increased from low to medium, and a smaller increase as it increased from medium to high density. The same trends held in the case of bleached pulps. Because of the limited scale of this trial and the fact that the medium density sample yielded pulps with Kappa numbers completely out of line with the pulps from the other two samples, it is not possible to draw firm conclusions about the relationship between density and pulping characteristics, or the merit of density for predicting the quality of pulp. However, in this and in earlier similar work (Tropical Products Institute Report L25) it appears that low density trees can have the economic disadvantage of not only higher handling costs but also lower pulp yields per bone dry ton, and the technical disadvantage of giving the lowest tearing strength although with somewhat higher bonding strengths. The choice between medium and highest density is obscure. The conclusion might be different with trees at a different age and site conditions because both these affect the general level of pulp strength and they also affect the relationship between bonding and tearing strength

Pulping characteristics of Dicymbe altsoni from Guyana

A sample consisting of one tree of Dicymbe altsoni from Guyana was examined to determine its pulping characteristics. This sample was not large enough to produce definitive results, but it was considered that an indication could be obtained. Bark content, wood density, chemical analyses and fibre dimensions are reported. Sulphate cooks yielded 48.1% 9f screened pulp with a kappa number of 33.1 to 44.3% of pulp with a kappa number of 22.9. Bleaching trials by a four-stage sequence, using successive applications of chlorine, sodium hydroxide, sodium hypochlorite and chlorine dioxide, produced pulp with a brightness of 83% (absolute scale). It is believed that if D. altsoni was mixed with the six Guyanan species examined earlier, it would not make any major difference to the quantity or quality of the pulp

Pulping characteristics of Pinus oocarpa grown on Mountain Pine Ridge, Belize

A single sample of Pinus oocarpa from Mountain Pine Ridge, Belize was pulped by the sulphate process. The results of pulping and pulp evaluation, together with chemical analysis of the wood and fibre dimensions are reported. The sample consisted of twenty trees selected at random from a naturally regenerating forest. The average age of the trees was estimated as 30 years with a range of 20 to 46 years. Chemical analysis showed the wood to have an a-cellulose content of 48.9% and a lignin content of 28.7%. The fibres were 3.13 mm long, 49.8 micrometres wide and had walls 6.9 micrometres thick. Pulping by the sulphate process yielded between 38% and 44% of unbleached pulp. These yields were lower than usually found in pines. The pulp had strength characteristics generally similar to those of pulps from Southern Pines of the USA. Compared with pulps obtained from P. caribaea growing in the same area, it was found that P. oocarpa gave lower yields of marginally better pulps

Pulping characteristics of Eucalyptus saligna/grandis growing in Uganda

Three samples of Eucalyptus saligna/grandis grown in Uganda were examined to determine wood density, chemical composition, fibre dimensions, and pulping characteristics by the sulphate process. The samples were of 9-year-old trees and 17-year-old trees from the Kajansi Forest Reserve, and 11-year-old trees from Nagojje Forest Reserve. The differences in wood density, chemical composition.and fibre dimensions were small and unlikely to be significant in commerical production, but there were indications that both age of sample and growing conditions affect wood density, fibre dimensions and the strength characteristics of pulp. All three samples when pulped by the sulphate process yielded more than 50% of a bleachable pulp with good strength characteristics. Pulp from the 9-year-old sample from Kajansi had the highest bonding strength; that from the 17-year-old sample from Kajansi the highest tearing strength; that from the 11-year-old sample from Nagojje was weakest in all respects. The pulps could be bleached by a four-stage process of successive applications of chlorine, sodium hydroxide, sodium hypochlorite and chlorine dioxide to yield pulps with satisfactory brightness (86, Mg0=1 00) and with strength properties only a little lower than those of unbleached pulps