Brightness, illumination

Rapid addition of bromine to the dried solvent to make a 10% solution caused a vigorous reaction with gas evolution. As this happened in a newly installed brightly illuminated fume cupboard lined with a reflective white finish, photocatalysed bromination of the solvent may have been involved, as has been observed in chlorine-ether systems. 

Similarly, Hole et al. (88,89) found no significant change in the activity of 5,7-DHT-lesioned rats tested in their home cages and a reduced activity in treated rats tested in a novel open field. Since the lesioned animals were demonstrably hyperreactive to environmental stimuli, and the open field was brightly illuminated, the authors interpreted the reduced activity as reflective of an increase in reactivity or emotionality. 

The depth of color is determined as follows. The carbon black is rubbed with a binder (e.g., linseed-oil) to form a paste which is applied in a thick coat on a glass plate. A colorimeter is used to measure the diffuse reflection of light through the glass. The color depth and hue of the paste can be determined from the intensity and spectral distribution of the diffusely reflected light [4.32]. The color depth can also be determined by visual comparison of the paste with pastes of known blackness under very bright illumination. 

Figure 7.6 A purple circular piece of paper is placed on top of the color Mondrian. This piece of paper looks purple to a human observer if the whole Mondrian is brightly illuminated (a). However, if the surrounding illumination is attenuated while at the same time the illumination of the circular piece of paper is kept unchanged, then the piece of paper looks white to a human observer (b). Note that in order to illustrate the results of this experiment the circular area was actually drawn with white to produce the image shown in (b).

Test apparatus a 2-compartment box, 30 x 30 x 30 cm each with one black, and one transparent brightly illuminated boxes, separated by a sliding door (5). 

To achieve greater pupillary dilation and overcome the constrictor effect of cholinergic stimulation, particularly on exposure to bright illumination, both phenylephrine and hydroxyamphetamine can be used in conjunction with a cholinergic antagonist, such as tropicamide or cyclopentolate. Additionally, phenylephrine 1% combined with a low concentration of 0.2% cyclopentolate (Cyclomydril) is recommended for neonates for funduscopic examinations. 

Figure 9-5 Mean mydriatic dose-response curves for tropicamide 0.25%, 0.5%, 0.75%, and 1% under normal and bright illuminance. (SD = standard deviation.) (Reprinted with permission from Pollack SL, Hunt JS, Poise KA. Dose-response effects of tropicamide HCl. Am J Optom Physiol Opt 1981 58 361-366.)...

When anisocoria is greater in bright illumination, the dilated pupil is considered abnormal until proven otherwise. The differential diagnosis of this dilation includes... 

Figure 22-2 Dilation lag in 72-year-old man with left-sided Homer s syndrome. (A) Obvious anisocoria in bright illumination. Note greater anisocoria at 4 to 5 seconds in darkness (B) as compared with the anisocoria at 10 to 12 seconds in darkness (C).

Relative mydriasis in bright illumination Absent or poor light reaction Slow (tonic) contraction to prolonged near effort Slow redilation after near effort Vermiform movements of pupillary margin (i.e., sector palsies of iris sphincter)... 

The most common symptoms reported by patients are changes in color vision and impaired vision. These symptoms can take many forms and include the visual phenomena listed in Box 35-4. A common symptom is snowy vision (objects appear to be covered with frost or snow), and this observation is intensified in brightly illuminated environments. There is also evidence that digoxin may contribute to rhegmatogenous retinal detachment by decreasing the normal adhesion of the retina to the RPE. 

If the two beams have a well-defined phase relationship, they will interfere to produce regions of darkness as well as regions of bright illumination. It is this coherent interference that has been used for over half a century to produce holograms in thick photographic emulsions such as silver halides. 

Place the sample solution containing not more than 100 pg of S (as a sulphate) in a Nessler cylinder. Acidify with 2 ml of 2 M HCl, add 10 ml of ethanol and water to 40 ml, pour in quickly 5 ml of BaC solution, and stir well. After 15 min, compare the turbidity with a series of standards prepared simultaneously. The cylinders should be observed from above, against black paper, in a uniformly brightly illuminated place. 

GV150013 has shown activity in a number of animal models of anxiety. In the mouse black/white box test GV150013 increased the time that naive mice remain in a brightly illuminated section of an activity box The effect was dose related and significant increases were measured at 0.1, 0.3 and l. Ong.kg 1.Similar anxiolytic effects were seen in the rat social interaction test and the marmoset human threat test [25]. The ED50 values are given in table 5. 

Practically this means that high signal frequencies are detected at bright illumination while poor illumination results in low-pass filtering in each pixel. Log amplification inserts an amplification noise proportional to the amplification factor. In contrast, exponential attenuation results in a constant SNR over most of the range because the noise is proportional to the square root of Af Fig. 7.8.6 shows the difference in dynamic behavior of a CCD and a nonlinear CMOS sensor. 

Rubisco s second activity—oxygenase—can be troublesome. If concentrations of O2 are high, as they are likely to be in a brightly illuminated plant, the reaction between RuBP and O2 can compete with carboxylation (Zelitch 1975). This process of photorespiration has a doubly negative result CO2 is not fixed and a mole of RuBP is destroyed. The problem is particularly severe for plants that grow in environments in which they must minimize amounts of water lost by evapotranspiration. If they close their stomata, they also tend to retain O2 and to impede access to atmospheric CO2. The ratio of CO2 to O2 declines and photorespiration is exacerbated. Two strategies, distinctly different but closely related, have evolved to overcome this problem. 

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