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Under consideration are the classification problem and application of simple neural networks for solving the problem. A robust modification of the error backpropagation algorithm is proposed and used for training neural networks. Some proposition is proved that allows us to construct the proposed modification with the Huber loss-function. In order to study the properties of the so-obtained neural network, a number of computational experiments are carried out. We consider various values of the outliers' fraction, noise level, and training and test samples sizes. Inspection of the results shows that the proposed modification can significantly increase the classification accuracy and learning rate of a neural network when working with noisy data. [ABSTRACT FROM AUTHOR]

The regularities of the thermal relaxation of structural defects (paramagnetic centers and microdistortions), as well as the sizes of coherent-scattering regions and the external surface, of mechanically activated МоО have been studied with the use of X-ray diffraction, electron paramagnetic resonance, and adsorption/desorption methods. It has been revealed that heating of activated samples at temperatures below 450°C is accompanied by the death of paramagnetic centers, annealing of microdistortions, and liberation of molecular oxygen. It has been assumed that oxygen results from the rupture of deformed Mo-O-Mo bridge bonds formed by its atoms. Above 450°C, recrystallization processes occur, which are accompanied by an increase in the sizes of the coherent-scattering regions and the MoO (monoclinic) → MoO (orthorhombic) phase transition. The thermal stability of the external particle surface depends on mechanical activation conditions. For samples activated at early stages of activation (fracture regime), the specific surface area decreases by more than an order of magnitude, when a temperature of 450°C is reached. At higher activation doses (friction regime), the sample is not sintered in the same temperature range. [ABSTRACT FROM AUTHOR]

Defect structure of mechanically activated MoO has been studied with the use of X-ray diffraction, Raman spectroscopy, electron paramagnetic resonance, laser granulometry, and adsorption methods. Two stages of mechanical activation have been distinguished. At mechanical activation doses below 1 kJ/g, the fracture of oxide particles is the main process. At this stage, MoO particle sizes decrease from 30 μm to 60 nm and specific surface area linearly increases to 30 m/g, the sizes of coherent-scattering regions decrease to 18 nm, paramagnetic centers are accumulated, and the Raman spectral bands corresponding to three different types of Mo-O bonds widen and shift. At doses above 1 kJ/g, the main process consists in the friction and aggregation of particles, which is accompanied by some reduction in the specific surface area and an increase in the particle sizes. At the stage of friction, the phase transition from an orthorhombic modification to a monoclinic modification of MoO occurs seemingly due to a shift of one layer of the material in plane (100). The shift is accompanied by the accumulation of lattice microstrains in the same plane, formation of 'stressed' Mo-O-Mo bridge bonds, and a substantial rise in the concentration of Mo radicals. The maximum total concentration of paramagnetic centers is 1 × 10 g. It may be assumed that the radicals are formed due to the rupture of the most stressed molybdenum-oxygen bridge bonds. [ABSTRACT FROM AUTHOR]

Mechanical activation has been employed to produce highly reactive energy-saturated Mg/(-CF-) composites, chemical transformations in which are initiated by either heating or shock-wave loading. The structure and reactivity of these composites have been analyzed with the use of X-ray diffraction, microscopy, thermogravimetry, calorimetry, and the measurement of combustion and detonation velocities. Mechanical activation is accompanied by the formation of a magnesium/fluoroplastic composite structure with the intercomponent contact area as large as 6 m/g and accumulation of chaotically arranged dislocations to concentrations as high as 6 × 10 cm, basal and prismatic deformation stacking faults (the maximum probabilities of their formation are 2.1 and 1.4%, respectively), and boundaries of coherent-scattering regions in magnesium. In fluoroplastic, disordering and partial amorphization of the structure take place. Mechanical activation leads to a dramatic increase in the propagation velocity of Mg + (-CF-) → MgF + C chemical reaction in the explosive combustion regime (to 400 m/s) and the development of knocking combustion, in which the reaction propagates at a velocity as high as 1100 m/s. The optimal dose of mechanical activation (7-8 kJ/g), at which the maximum velocity of reaction propagation is reached, has been determined. The use of a 'slow' heating in the cell of a calorimeter in combination with the mass-spectral analysis of evolved gases has made it possible to distinguish processes of three types in the thermally activated interaction between magnesium and fluoroplastic. The formation of MgF at temperatures below 300°C seems to be due to the interaction between defects in magnesium (dislocations and stacking faults) and macromolecules. The reaction occurring at 300-420°C with a slight thermal effect is caused by the solid-phase interaction between magnesium and fluoroplastic brought in contact with one another. The main contribution to the conversion is made by the processes that take place at temperatures above 420°C and are relevant to the thermal depolymerization of fluoroplastic. The layered structure of the composite and the large area of the intercomponent contact ensure the penetration of gaseous products of depolymerization into the bulk of magnesium particles and the completeness of the interaction. [ABSTRACT FROM AUTHOR]

The genesis of a defective structure (particle size, size of coherent scattering regions (CSRs), dislocation concentrations, and two types of deformation and twin stacking defects (SDs)) of magnesium during its mechanical activation in a vibrating mill in the presence of liquid additions was studied by X-ray diffraction (XRD) analysis, microscopy, and adsorption (BET) method. The dynamic mechanical properties were checked for the activated samples using a K-44-2 vertical impact machine. The ability of magnesium to be oxidized in air was checked by heating it in the cell of a differential scanning calorimeter. At mechanical activation doses of less than 5 kJ/g, the accumulation of chaotically arranged dislocations and deformation SDs was accompanied by an increase in the plasticity of the material. At higher doses, polygonization of dislocations led to a drastic decrease in the CSR size and dislocation run, leading to embrittlement of the material. The changes in the mechanical properties were confirmed by symbatic changes in the outer particle size and showed themselves on the pressure oscillograms during the impulse loading of pressed Mg layers. Mechanical activation led to an increase in the level of oxidation of magnesium with oxygen, but did not affect the temperature of the start of oxidation. A method for activating magnesium with additions was suggested and led to the formation of highly disperse magnesium samples with the oxidation temperature lowered by 150°C. [ABSTRACT FROM AUTHOR]

Maselli RA, Arredondo J, Cagney O, Mozaffar T, Skinner S, Yousif S, Davis RR, Gregg JP, Sivak M, Konia TH, Thomas K, Wollmann RL. Congenital myasthenic syndrome associated with epidermolysis bullosa caused by homozygous mutations in PLEC1 and CHRNE. Mutations in the plectin gene ( PLEC1) cause epidermolysis bullosa simplex (EBS), which may associate with muscular dystrophy (EBS-MD) or pyloric atresia (EBS-PA). The association of EBS with congenital myasthenic syndrome (CMS) is also suspected to result from PLEC1 mutations. We report here a consanguineous patient with EBS and CMS for whom mutational analysis of PLEC1 revealed a homozygous 36 nucleotide insertion (1506_ 1507ins36) that results in a reduced expression of PLEC1 mRNA and plectin in the patient muscle. In addition, mutational analysis of CHRNE revealed a homozygous 1293insG, which is a well-known low-expressor receptor mutation. A skin biopsy revealed signs of EBS, and an anconeus muscle biopsy showed signs of a mild myopathy. Endplate studies showed fragmentation of endplates, postsynaptic simplification, and large collections of thread-like mitochondria. Amplitudes of miniature endplate potentials were diminished, but the endplate quantal content was actually increased. The complex phenotype presented here results from mutations in two separate genes. While the skin manifestations are because of the PLEC1 mutation, footprints of mutations in PLEC1 and CHRNE are present at the neuromuscular junction of the patient indicating that abnormalities in both genes contribute to the CMS phenotype. [ABSTRACT FROM AUTHOR]

Previously, we and others have demonstrated the association of a C/T single nucleotide polymorphism (SNP), in the Kozak sequence of CD40, with Graves' disease (GD). Here, using an expanded data set of patients, we confirm the association of the CD40 SNP with GD (n=210, P=0.002, odds ratio (OR)=1.8). Subset analysis of patients with persistently elevated thyroid peroxidase (TPO) and/or thyroglobulin (Tg) antibodies (Abs), (TPO/Tg Abs), after treatment (n=126), revealed a significantly stronger association of the SNP with disease (P=5.2 × 10−5, OR=2.5) than in GD patients who were thyroid antibody-negative. However, the CD40 SNP was not associated with TPO/Tg Abs in healthy individuals. Next, we tested the CD40 SNP for association with Myasthenia Gravis (MG), which, like GD is an antibody-mediated autoimmune condition. Analysis of 81 MG patients found no association of the SNP with disease. Functional studies revealed significant expression of CD40 mRNA and protein in the thyroid (target tissue in GD) but not in skeletal muscle (target tissue in MG). Combined, our genetic and tissue expression data suggest that the CD40 Kozak SNP is specific for thyroid antibody production involved in the etiology of GD. Increased thyroidal expression of CD40 driven by the SNP may contribute to this disease specificity.Genes and Immunity (2007) 8, 205–214. doi:10.1038/sj.gene.6364375; published online 8 March 2007 [ABSTRACT FROM AUTHOR]

Using cone valves, it is possible to supply both minimal and design water flow rates, which cannot always be achieved using other types of valves. [ABSTRACT FROM AUTHOR]

This simulation study examined the effects of proportional increases in light output throughout the entire headlamp beam pattern on visibility. The baseline beam pattern was a median market-weighted US tungsten–halogen low-beam pattern. Ten derived beam patterns were obtained by multiplying each point in the baseline beam pattern by a constant that ranged from 1.1 to 2.0, in increments of 0.1. Finally, for comparison, we also used the median market-weighted US high-beam pattern. Visibility changes were estimated by calculating the change in the reach of a 3-lux line 0.25 m above the road surface, for both straight and curved roadways. The results indicate that substantial gains in visibility on straight roadways require an increase of about 50% in the overall light output of low beams. On curves, obtaining a substantial gain in visibility in several lateral positions would require significantly greater increase in light output. These results provide an enhanced baseline against which to compare other potential improvements in low-beam visibility, including more localized changes in static beam patterns and adaptive headlighting systems. [ABSTRACT FROM AUTHOR]

The article presents information on technological developments related to gastrointestinal endoscopy. In this regard, one major technical development is endoscopic ultrasonography (EUS). EUS is an advanced technique, which will help in future innovation. EUS has not been universally accepted by non-gastroenterologists, because it is very costly, and has a narrow focus. Endoscopic research requires funding by the government. More gastroenterologists need to be trained for endoscopic research.

This study examined the potential effects of the spectral power distributions of mercury-free high-intensity discharge (HID) headlamps on discomfort glare for oncoming drivers and on colour rendering of retroreflective traffic materials. In both cases, the effects of mercury-free HID light sources were compared to the changes in these properties that occurred when the tungsten–halogen light sources were replaced with traditional (mercury containing) HID light sources. Specifically, the effect on discomfort glare was estimated by comparing the chromaticities of nine mercury-free light sources with the chromaticities of 17 traditional HID light sources. Similarly, the effects on colour rendering were estimated by comparing the chromaticities of seven red retroreflective materials (red being the most important messenger of meaning in traffic control) when illuminated by the mercury-free light sources with the chromaticities of the same materials when illuminated by the traditional HID light sources. The main findings are: (1) The discomfort glare from the mercury-free HIDs is predicted to be comparable to that from the 'bluest' of the traditional HIDs. (2) Colour rendering with headlamps using the mercury-free HIDs is likely to be acceptable. (3) The use of mercury-free HIDs is unlikely to have appreciable effects on the relative brightness of coloured retroreflective materials. [ABSTRACT FROM AUTHOR]

Because of rapid improvements in the light output of light-emitting diodes (LEDs), serious consideration is being given to using LEDs as light sources for headlamps. This analytical study examined the potential effects of LEDs on discomfort glare for oncoming drivers and on colour rendering of retroreflective traffic materials. In both cases, the effects of LED light sources were compared to the changes in these properties that occurred when the traditional tungsten halogen light sources were replaced with high-intensity discharge (HID) light sources. Specifically, the effect on discomfort glare was estimated by comparing the chromaticities of seven LED light sources (considered for use in headlamps) with the chromaticities of the light sources from 17 actual HID headlamps. Analogously, the effects on colour rendering were estimated by comparing the chromaticities of seven red retroreflective materials (red being the most important messenger of meaning in traffic control) when illuminated by the LED light sources with the chromaticities of the same materials when illuminated by the HID light sources. Based on our analyses, headlamps using the currently considered range of LEDs are predicted to result in: 1) more discomfort glare than the current HID headlamps, and substantially more discomfort than tungsten halogen headlamps; 2) acceptable colour rendering; and 3) no appreciable effects on the relative brightness of red retroreflective materials. [ABSTRACT FROM AUTHOR]

This study was designed to compare the illuminated surface areas of high-intensity discharge (HID) and tungsten halogen low-beam headlamps in the USA. A sample of 20 tungsten halogen lamps and 17 HID lamps for model year 2000 vehicles in the US was examined. The illuminated surface area was determined using a modified version of an Economic Commission for Europe (ECE) method for evaluating the illuminated surface of signalling devices. The main finding is that the HID low (passing) beams generally have smaller illuminated surface areas than do the tungsten halogen low beams. Because smaller light sources result in more discomfort glare (presumably via greater luminance), the present finding suggests that the smaller illuminated area is one reason for drivers reporting more discomfort from HID lamps. An implication is that the increased discomfort from HID lamps could be reduced by increasing their illuminated surface area. [ABSTRACT FROM AUTHOR]

This in-traffic study evaluated driving performance with and preference for high-intensity discharge (HID) low beam headlamps. Subjects drove two identical luxury sedans. One vehicle was equipped with HID low beams and the other with tungsten halogen low beams. The main difference between the two beams was that the HID lamps provided more spread light. Driving performance was evaluated by analysing steering frequencies. The hypothesis was that the wider beam pattern of the HID lamps would be beneficial by reducing the steering effort in the 0.3-0.6 Hz range, which has been used in previous studies as an index of steering-task difficulty. The main finding is that the wider HID beam pattern made lane maintenance less demanding, as measured by a reduction in the steering frequencies between 0.3 and 0.6 Hz. The implication is that HID headlamps may be beneficial to safety, because their wider beam pattern allows more of the limited information processing resources of drivers to be allocated to other tasks. When the subjects were not primed before driving to pay attention to the headlamps, they did not show, as a group, preference for either type of lamp. However, when they were told to pay attention to the headlamps, they overwhelmingly preferred the HID lamps. [ABSTRACT FROM AUTHOR]

Previous research has shown that, as expected, fast-rise signals (such as LEDs and neon lamps) lead to shorter reaction time than that obtained with slower-rise signals (such as incandescent lamps). This study, in two converging experiments, investigated whether rapid rise time makes turn signals more resistant to masking from an adjacent headlamp. The first experiment used a method of limits to obtain luminous intensity thresholds for LED and incandescent turn signals in the presence of headlamp glare. In the second experiment, subjects judged the relative conspicuity of simultaneously presented LED and incandescent turn signals when they flanked an illuminated headlamp. The results of the two experiments were consistent: there was no difference between the two light sources in either detection threshold or judged conspicuity. These results suggest that faster rise time does not affect the resistance of turn signals to headlamp masking. [ABSTRACT FROM AUTHOR]

This study measured direct and rearview-mirror glare illuminances produced by low-beam headlamps in a sample of 22 passenger vehicles. The glare illuminances were measured for 12 common glare situations that were defined by a full factorial combination of three scenarios (oncoming driver, center rearview mirror of a preceding driver, or driver-side mirror of a preceding driver one lane to the right), two longitudinal distances (25 m or 50 m), and two vertical locations (illuminated vehicle being either a car or a light truck/van/sport utility vehicle). The measurements were made outdoors at night on asphalt pavement. The median illuminances (not taking into account window transmittance or mirror reflectance) ranged from 0.5 lux for an oncoming driver of a light truck/van/sport utility vehicle at a distance of 50 m, to 3.4 lux at the driver-side mirror of a preceding car at 25 m one lane to the right. The ratios of the maxima and the minima measured for each of the 12 glare situations were large, ranging from about 5:1 to 36:1. The median actual illuminances were compared to the median expected illuminances based on a recent, laboratory-measured, representative sample of US low-beam patterns, taking into account the possible effects of dirt, voltage, misaim, and pavement reflectance. This analysis indicates that the actual illuminances could be very well modeled using the laboratory-measured beam patterns and assuming a linear relationship between the light output of clean and dirty headlamps. Additional analyses evaluated the relationships between headlamp mounting height and glare illuminance. [ABSTRACT FROM AUTHOR]

Previous studies have shown that the visibility of a front turn signal is decreased if a headlamp is located near the turn signal. Consequently, both the US and ECE regulations require the turn signals to be more intense in such situations. However, it is unclear how adjacent light sources affect suprathreshold aspects, such as conspicuity. The present field study was designed to examine the effects of several factors on the night-time conspicuity of front turn signals. Specifically of interest were the effects of the number, luminous intensity, and spatial arrangement (including spacing) of the potentially interfering lamps. The following are the main findings: (1) The conspicuity of a turn signal was significantly lower when it was separated from a 1000 cd low-beam headlamp by 50 mm rather than 100 mm (centre-to-edge). A 200 cd turn signal at 100 mm was equal in conspicuity to a 288 cd turn signal at 50 mm. This effect is smaller than the effects obtained in previous studies using threshold-visibility paradigms. (2) Adding a second masking light source, at the same 50-mm spacing as the first masking light source, significantly influenced the conspicuity of the turn signal. The effect of the second masking source can be compensated for by an increase in the turn signal intensity corresponding to 8.5% of the intensity of the second masking source. (3) The conspicuity of the turn signal was unaffected by the spatial arrangement of two masking light sources. [ABSTRACT FROM AUTHOR]

Summary. Sporadic Amyotrophic Lateral Sclerosis (SALS) is a fatal neurologic disease characterized by degeneration of motor neurons in the spinal cord, brainstem and cortex. While familial cases of ALS exist, the sporadic form accounts for the majority of adult-onset cases. It has been hypothesized that the neurodegenerative mechanisms underlying SALS might arise from glutamate-mediated excitotoxicity and mitochondrial dysfunction. Studies on autopsied SALS spinal cord and brain have reported decreased cytochrome oxidase activity, decreased astrocytic glutamate-transporter protein, and alterations of glutamate levels and glutamate metabolizing enzyme activities. We conjectured that if alterations in glutamate metabolism and cytochrome oxidase activity occur in the SALS central nervous system these alterations may also be manifested in peripheral tissues such as platelets in living SALS patients. In this study we compared the activities of cytochrome oxidase, citrate synthase, glutamate dehydrogenase and glutaminase in platelets from SALS and control subjects. We found that there were no differences in any of the enzyme activities measured between the two groups. Our data argue against generalized ubiquitous biochemical alterations of these enzymes in SALS patients. [ABSTRACT FROM AUTHOR]

There is some concern that vehicle direction indicator lamps with clear outer lenses make it difficult in bright, sunny conditions to decide whether the signal is on or not. This study photometrically evaluated, under bright, sunny conditions, both luminance contrast and colour contrast between the on and off states for direction indicator lamps that use either an amber lens or a dear lens. The results indicate that luminance contrast between the on and off states is greater for lamps using an amber lens. On the other hand, the results indicate that colour contrast between the on and off states is greater for lamps using a clear lens. Because luminance contrast is likely to be the primary variable influencing driver performance, these results suggest that using clear-lens direction indicators is likely to make it more difficult to determine, in bright, sunny conditions, whether the signal is on or not. However, the magnitude of the decrement in real-world performance with dear-lens signal lamps remains to be ascertained. [ABSTRACT FROM PUBLISHER]

This study compared the quantitative influence of a variety of factors on the performance of low-beam headlamps. The factors included were vertical aim, horizontal aim, mounting height, lateral separation, lens dirt, lamp voltage, number of functioning lamps, vehicle type, beam pattern and light source. The following aspects of headlamp performance were considered: visibility of pedestrians, visibility of road delineation, visibility of vehicle reflex reflectors, visibility of rettoreflective traffic signs, visibility of targets near the road expansion point, glare directed towards oncoming drivers, glare reflected from wet pavement towards oncoming drivers, glare directed towards rearview mirrors of preceding vehicles, and foreground illumination. A sales-weighted average US beam pattern, with lamps mounted at sales-weighted average locations, formed the basis for most of the analyses. The results indicate that, from among the factors studied, vertical aim is overwhelmingly the most important factor in influencing the performance of low-beam headlamps. The second most important factor is the number of functioning lamps. The main implication of this study is that major improvements in current (fixed as opposed to adaptive) low-beam headlighting could be achieved primarily by better control of vertical aim and by use of longer-life headlamps. [ABSTRACT FROM PUBLISHER]

This study evaluated changes in the light output of rear signal lamps as a function of dirt accumulated during a 482 km drive, representing ten days' driving for a typical United States driver. The complete route was traversed on three separate occasions, under each of the following environmental conditions: dry, wet, and snowy/salty. Luminous intensity measurements were obtained for all US and European test points. Photometry for each of two stop lamps was performed twice after the completion of each drive: first 'as is' and then after cleaning. The results indicate that dirt deposits tended to cause the light output to decrease at the points tested. The reductions after the dry drive were all less than 8%. However, after the wet and snowy/salty drives reductions of more than 25% occurred at several test points, with a maximum reduction of 37%. The test percentage reductions occurred for the points at and near the optical axes of the lamps, which had the highest original intensities, and at which maintaining adequate intensity is presumably most important. A theoretical analysis of the changes caused by dirt indicates that this is the pattern of results that wild usually occur. A full evaluation of the significance of the effects of dirt that are quantified in this paper should be done in the context of other factors that affect signal-lamp intensity, such as vehicle voltage control and lamp design. It may also be important to measure more fully the range and distributions of dirt conditions in the real world. However, the present results demonstrate that, within the range of common weather conditions, dirt can cause reductions of signal-lamp intensity that are large enough to be of concern, especially for the relatively important positions at and near the optical axes of signal lamps. [ABSTRACT FROM PUBLISHER]

This analytical study examined the effects of mounting height on discomfort glare from reduced-power high-beam headlamps used as automotive daytime running lamps. Of interest were the effects for mounting heights between 0.864 m (34 in) and 1.372 m (54 in) - the range in which full-power low beams are currently allowed, but reduced-power high beams are not. Three analyses were performed. The first analysis involved estimating the illuminance reaching a preceding driver via rearview mirrors. The second analysis compared glare illuminance from reduced-power high beams with that from full-power low beams. The third analysis evaluated the expected changes in discomfort-glare ratings from reduced-power high beams as a function of increased mounting height. The analyses were based on photometric information from five high beams and 43 low beams from lamps manufactured for the United States market. They were performed for five following distances and three lateral offsets of the vehicles. The results indicate that allowing reduced-power high beams with mounting heights between 0.864 m and 1.372 m would not appreciably increase discomfort glare for preceding drivers as compared with (a) glare from reduced-power high beams at a mounting height of 0.864 m, or with (b) glare from currently allowed full-power low beams. [ABSTRACT FROM PUBLISHER]

This study evaluated changes in the light output of low-beam headlamps as a function of dirt accumulated during a 482 km route, representing a 10-day amount of driving for a typical United States driver. The complete mute was traversed on three separate under each of the following environmental conditions: summer while dry, summer white wet, and with road salt. Candela matrices were obtained for a rectangular central portion of the beam, extending from 20° left to 20° right, and from 5° down to 5° up (in 0.5° steps). Photometry for each of two lamps was performed twice after the completion of each drive, first 'as is' and then after cleaning. The results indicate that dirt deposits tended to cause the light output to decrease below horizontal and increase near and above horizontal. The changes in the tight output differed between the driver-side and passenger-side lamps, especially after the two summer drives. The largest changes occurred after the winter drive, with the decreases and increases in a large part of the beam for both lamps exceeding 25%, and with some of the increases exceeding 50%. At the United States, European and Japanese test points that control road illumination, the dirt effects tended to reduce the light output, and some of these decrements exceeded 25%. On the other hand, at test points that control glare, the din effects tended to increase illumination, but none of these increases exceeded 25%. [ABSTRACT FROM PUBLISHER]

This study evaluated subjects' impressions of performance of high-intensity discharge (HID) headlamps after in-traffic experience, with an emphasis on colour appearance of red stop signs. In the first of two tasks, subjects drove (or rode) for half an hour on a variety of roads in a car equipped with either HID or tungsten-halogen low-beam headlamps. Instructions did not mention colour appearance. The second task involved a direct comparison of HID and tungsten-halogen headlamps. In this task, subjects drove (or rode) twice along a 7-minute route in a residential area, and they were instructed to pay attention to the colour appearance of stop signs and other objects. The main finding from Task 1 is that subjects who experienced HID headlamps did not report more (or fewer) spontaneous negative comments on colour appearance of stop signs or other objects than did subjects who experienced tungsten-halogen headlamps. Furthermore, the evaluations of the overall performances of the two types of headlamps were not different. In the direct comparison of Task 2 there was no evidence of problems with colour appearance when using HID headlamps. Moreover, subjects preferred HID headlamps in terms of the overall performance, and in making stop signs and other objects stand out from their background. However, this preference for HID headlamps was present only for subjects who had the relatively extended exposure to the HID headlamps in Task 1. The present results provide no evidence for problems with colour appearance of stop signs and other objects when using HID headlamps. Furthermore, the study provides evidence that observers perceive HID headlamps as helping stop signs and other objects to stand out from their background. The results imply that given a somewhat extended exposure to HID headlamps, drivers would prefer them over current tungsten-halogen headlamps. [ABSTRACT FROM PUBLISHER]

The amount of light reflected from a retroreflective traffic sign decreases with an increase in the observation angle—the angle between the headlamp, the sign, and the eyes of the driver. Mainly because of the increased seated eye height of truck drivers, the actual observation angles are greater for them than they are for car drivers. Consequently, there is concern about the impaired night-time detection and legibility of retroreflective signs for truck drivers. The present study evaluated the relative amount of light reaching drivers of different types of vehicle by using survey data collected in 1989 by the Transport and Road Research Laboratory (TRRL) in England. The TRRL data included driver eye heights and headlamp mounting heights for 445 vehicles. The present analysis considered three sign locations on a straight roadway: left shoulder, centre, and right shoulder. Two viewing distances were included: 152 m (500 feet) (typical of a sign-legibility distance), and 305 m (1000 feet) (typical of a sign-detection distance). The analysis considered both the differential amount of illumination impinging on the signs from headlamps of trucks and cars, as well as the differential amount of the light reflected from the signs in the direction of truck drivers and car drivers. The main results are that for the viewing distance of 152 m, the amount of light reaching a truck driver can be as low as 25% of the light reaching a car driver; the corresponding percentages for the viewing distance of 305 m are as low as 68%. These reductions were then related to the expected effects on sign legibility and detection. The results imply that the increased eye height of truck drivers could have a major effect on the legibility of retroreflective traffic signs, but only a modest effect on their detection. [ABSTRACT FROM PUBLISHER]

This laboratory study evaluated the effect of the size of the glare source on discomfort glare. The subjects performed two simultaneous tasks: continuous compensatory tracking, and evaluation of discomfort from glare stimuli presented periodically in the near visual periphery. The glare stimuli were circles of two sizes (approximately 0.3 and 0.6° in diameter), and produced five illuminance levels (from 0.03 to 3.1 lux) at the observer's eye. Subjects used a nine-point response scale to evaluate discomfort glare. The results indicate that there was a small but statistically significant effect of the size of glare source, with the smaller glare stimuli resulting in more discomfort glare. The mean difference over the range of glare illuminances tested was 0.2 points on the nine-point response scale. [ABSTRACT FROM PUBLISHER]

This study investigated the effects of prior headlighting experience on ratings of discomfort glare from headlamps in an actual driving situation. Specifically, discomfort glare ratings given by West Germans who had recently arrived in the United States and were, presumably, used to the relatively low levels of glare associated with headlamps in West Germany were compared with ratings given by U.S.-born subjects. The West German subjects reported significantly more discomfort than did the U.S. subjects. This finding is in agreement with the so-called range effect, in which subjective judgments are affected by the range of available stimuli. Consequently, the present findings support the hypothesis that discomfort glare ratings are affected by prior visual experience. [ABSTRACT FROM AUTHOR]

The oxidation of di-n-butyl sulfide and phenylmethyl sulfide by two vanadium (V) peroxocomplexes, e.g. VO(O)OCH, 1, and VO(O)(PIC)(HO), 2, in methanol, was investigated. The kinetic analysis of the reactions revealed significant mechanistic differences between the two peroxometal oxidants. In particular, 1 behaves as an electrophilic oxidant so that the transition state of sulfide oxidations by 1 may be described as a S 2 displacement on the peroxide oxygen whereas 2 acts as a radical oxidant in a process which has a substantial SET character. The role of the picolinaoo ligand in determining the reactivtty of 2 is discussed in terms of a decrease of the electrophilicity of the peroxide oxygen compared with 1 and of a stabilization of the radical metal species. [ABSTRACT FROM AUTHOR]

Light-scattering, which can be taken as an indicator of the transthylakoid proton-gradient, and chlorophyll a fluorescence, have been followed simultaneously during re-illumination of spinach leaves at different energy fluence rates and carbon dioxide concentrations. The slow fluorescence transient ('M peak'), which has been associated with photosynthetic induction, was observed in air only at the lower fluence rates used. Data are presented that indicate that M peaks in chlorophyll fluorescence kinetics can only be observed if there is also a simultaneous transient in light-scattering and that these transients are observed when the dark period is relatively long, fluence rate relatively low, and CO concentration relatively high. The results are discussed in relation to the varying demands on ATP by carbon assimilation during induction of photosynthesis at different carbon dioxide concentrations and the manner in which these variations influence the quenching of chlorophyll a fluorescence. [ABSTRACT FROM AUTHOR]

Provides information on endoscopic ultrasonography (EUS). Advantages of EUS compared to conventional transabdominal ultrasonography; Information on the local staging of gastrointestinal malignancy; Discussion on the general training in gastrointestinal endoscopy.

One hundred patients with familial adenomatous polyposis have prospectively undergone gastroduodenoscopy to identify and characterise polyps found. Forty six patients had polyps in the stomach or duodenum. Thirty five patients had adenomas (33 in duodenum, two in stomach) and 26 patients had fundic gland polyps. Some of these patients had polyps in the stomach and the duodenum. Adenomas in the duodenum were present in 33% of patients studied with Gardner's syndrome variant (p = 0.04). Adenomas were also more common in older patients. As adenomas may be a precursor of adenocarcinoma, routine surveillance of the stomach and duodenum with gastroduodenoscopy is recommended in patients affected with familial adenomatous polyposis. [ABSTRACT FROM PUBLISHER]