Accomodation response during a prolonged visual search task

The visual accomodative response is measured during dark field viewing and while engaged in a visual search task. A laser optometer is used to compare performance using microfiche and hard-copy displays. Results indicate a marked bias in the direction of the individual's resting accomodative state during all conditions of display viewing. Implications of these results and those from other studies are discussed with respect to future research in display design.     

Photoconductivities of poly(N-vinyl carbazoles) containing cation radicals

A study into the photoconductance of poly(N-vinyl carbazole) partly oxidized to introduce cation radicals is described (mole fraction < 4 × 10^?3). These materials are shown to be photoconductors whose response to illumination is time dependent. Their photoconductive behaviour has been studied as a function of extent of oxidation, field strength, temperature, light intensity and irradiating wavelength. The observed response is discussed in terms of a model for the amorphous state in which there are accessible levels in the forbidden gap for interaction with photopromoted electrons or holes. Variation in the role of level as trap or recombination centre with external conditions is shown to form, in part, an adequate model for behaviour. However, light intensity and temperature dependence does indicate that there is a significant change of the distribution of levels in the for-bidden gap as the temperature is reduced to ～ ?20°C, possibly due to a change in structure or mode of motion.     

The occurrence and seasonal changes in the isolation of Listeria spp. in shop bought food stuffs, human faeces, sewage and soil from urban sources

The successful campaign against smoking will long be celebrated as a landmark achievement of public health. Recently, a prominent component of this campaign has been the portrayal of environmental tobacco smoke as a major health risk. To this day, however, the scientific basis for this later contention remains speculative. The elevation of heuristic hypotheses into official precepts raises an intriguing ethical question: Should a claim of best intentions justify representing conjecture as scientific knowledge in public policy formulation?     

The use of palladium to obtain reproducible boundary conditions for permeability measurements using galvanostatic charging

The diffusion current of hydrogen through palladium in an electrochemical cell initially rises linearly with the charging current, reaches a steady “plateau” value, and then rises again. The diffusivity of hydrogen in palladium was measured using standard transient techniques in the initial region of low current density. Combining this value with the measured value of diffusion current at the plateau level gave a concentration of hydrogen at the entrance surface of the palladium that was the same for three different palladium thicknesses, and was equal to the saturation value in α palladium. It is proposed that this can be used as a known and reproducible effective hydrogen pressure (0.019 atm) if palladium is plated onto other metals before measuring their permeability in an electrochemical cell. Experimental evidence for this was obtained from permeability measurements made on several thicknesses of iron. Permeation studies were also made on AISI 410 stainless steel and tin plated mild steel. The measured value for electrolytic tinplate was 10⁷ times that expected from extrapolation of high temperature data. This could be attributed to grain boundaries or porosity covering 0.003 pct of the area. The permeability values of iron and stainless steel are 8.4 x 10¹² and 2.8 x 10¹³ H atom/cm • s • √atm, respectively. Former Postdoctorate Fellow at McMaster University     

The physical properties of tissue ablation with excimer lasers

The current controversy regarding the interaction between the output of the excimer laser and human tissue concerns the relative importance of photothermal and photoablative effects. Two experiments using an excimer laser on vascular tissue, aimed at defining the precise laser-tissue interaction, were performed. The experiments argue strongly in favor of photoablative effects that result from multiple photon interactions with ablated tissue.     

Sudden unexpected cardiac death: methods and results of a national pilot survey

In order to develop a methodology for measuring the occurrence and circumstances of sudden unexpected adult deaths due to cardiac and to unidentified causes throughout England, a stratified random pilot sample of 12 of the 133 coroner's jurisdictions in England was invited to survey prospectively a quota sample of 78 consecutive white Caucasians, aged from 16 to 64 years, with no history of ischaemic heart disease, who were last seen alive within 12 h of being found dead, and for whom a coroner's post-mortem examination found either a cardiac or no identifiable cause of death. Eleven (92%) coroners participated. In a median of 105 days (range 21-169), 65 cases (83% of the quota) were ascertained (54 (83%) males). Of the ascertained cases, registration forms were received on 62 (95%), tissue specimens on 63 (97%), and post-mortem reports on 58 (89%). Death was witnessed in 58%, of which 35% were 'instantaneous'. The median time from symptom onset to death was 40 min. In unwitnessed deaths, the median time since last being seen alive was 90 min. Sixty-eight per cent of all deaths were attended--by a relative in 34%, passer-by (8%), ambulance crew (32%), nurse (11%), doctor (38%), and police (9%). Cardio-pulmonary resuscitation was attempted in 38 of the 42 attended deaths. Sixty-seven per cent were taken ill at home, 12% at work, 12% in a public place, and 10% elsewhere. The certified cause of death was ischaemic heart disease in 89%, in whom coronary thrombosis and/or myocardial damage was absent in 6 cases (9%). In the remainder, the certified cause was hypertensive heart disease (5%), hypertrophic obstructive cardiomyopathy (3%), 'cardiomegaly' (1.5%) and 'sudden cardiac arrhythmia' alone (1.5%). A retrospective audit of coroner's records revealed the median case ascertainment rate was 75%. This approach to surveying sudden unexpected adult death nationally resulted in a high response rate (92%) from coroners, consultant pathologists and their staff, the identification of a large proportion of eligible cases, and complete information in most of the identified cases. In from 2% to 15% of cases, death may have been either purely dysrhythmic or due to a sudden adult death syndrome.     

The relationship between sports participation and self-esteem during early adolescence.

The main purpose of the present study was to examine the links between sports participation and self-esteem, with particular interest in the possible mediating role of physical self-esteem. The participants in this study were 382 students (167 boys; 215 girls) in Grades 5-8. Participants completed a series of paper and pencil measures, detailing their sports participation, as well as their self-perceptions concerning physical and general self-esteem. Sports participation was related to all indices of self-esteem and this was equally true for boys and girls. Two distinct but related factors were identified as components of physical self-esteem (Physical appearance and Physical competence), differentially associated with self-esteem for boys and girls. Results supported a mediational model, with physical self-esteem mediating the relationship between sports participation and general self-esteem. Significant sex differences were noted with regard to specific indices of physical self-esteem. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Photocatalytic Reforming of Glycerol over Gold and Palladium as an Alternative Fuel Source

The photocatalytic reforming of glycerol to hydrogen over palladium and gold modified TiO₂ catalysts is reported. The rate of hydrogen production exceeds that measured for the photoreforming of methanol over both catalysts with the palladium catalyst performing approximately four times better than the gold. The reaction occurs under ambient conditions and neither system suffered from poisoning after extensive testing. This therefore offers a potentially attractive route by which one of the major waste products from the manufacture of biodiesel can be converted into a useful product.     

Measurement of Muscle Exudate Protein Composition as an Indicator of Beef Tenderness

The objective of this study was to determine the relationship between the protein composition of muscle exudates and meat tenderness in beef. Frozen, intact beef strip loins (n = 24) were each divided into 3 equal portions (anterior, middle, and posterior). Steaks were removed from each portion, individually vacuum packaged, thawed at 4 °C, and aged for 0, 7, or 14 d. After the designated aging period, exudate was collected from the packaging and 1 steak from each strip loin portion was utilized for shear force measurements. Muscle exudates were analyzed for protein content (biuret assay) and composition (sodium dodecyl sulfate–polyacrylamide gel electrophoresis). Shear force decreased (P < 0.0001) with aging from 0 to 14 d. The protein concentrations of the muscle exudates were not influenced by the aging period and were not related to the amount of exudate expressed. Electrophoretic analyses of the muscle exudates indicated that with aging the relative abundance of 4 proteins decreased (P < 0.01) and 10 proteins increased (P < 0.05) within the protein profiles of the exudates. The relative abundance of the 167, 97, and 47 kDa proteins in exudates at day 0 were significantly correlated (|r| = 0.57 to 0.77) to shear force at day 14. These data demonstrate that exudate protein composition changes with postmortem aging and beef tenderness.