Shades of gray

Fig. 1. Nonbonded force evaluation may be distributed among processors according to atomic coordinates, as in spatial decomposition (left), or according to the indices of the interacting atoms, as in force-matrix decomposition (right). Shades of gray indicate processors to which interactions are assigned.

Fig. 2. Patches divide the simulation space into a regular grid of cubes, each larger than the nonbonded cutoff. Interactions between atoms belonging to neighboring patches are calculated by one of the patches which receives a positions message (p) and returns a force message (f). Shades of gray indicate processors to which patches are assigned.

When placed at a distance from the observer s eye the crosshatch lines merge and appear as a uniform shade of gray. There is a standard size for this chart (BS 2742C 1957), and this has the five shades from 0 to 4. The chart is usually viewed from a distance of 15 meters and hence has to be mounted on a tripod, which should not shadow the card. The chart should be set up in such a position that the smoke being measured has the same sky background as the chart. It should not be placed so that the sun is either directly behind the chart or directly in front of it. Comparisons can then be made between the shade of the smoke and that on the card. 

The miniature smoke chart. This does not have crosshatched lines but rather shades of gray, which correspond to the numbers. The chart can be viewed from approximately 1.5 m. 

Shades of Gray When repeat determinations are carried out on a sample and one or more of the individual results are outside the specs, the following criteria could apply ... 

Figure 3.1 Transaxial parametric images in units of V/ show regional [123I]5-IA binding to p2-nAChR prior to and 2 to 3.5 h and 4 to 5.5 h after smoking a single cigarette. The bar at the left illustrates shades of gray corresponding to V/ values.

Figure 12.1 Schematic representation of the mRNA templates usedin the translational tests. The relevant characteristics of the templates are indicated with different shades of gray. The lettering on the left is used to identify the template inTablel2.1.

Fig. 4. Domain structure of mammalian DNA methyltransferases. (a) The domain structure of the known DNA methyltransferases, depicting the conserved catalytic domain (dark box) and other identified domains. Conserved aminoacid motifs in the catalytic domain are shown in lighter shade of gray. (b) Schematic representation of the reported protein-protein interactions of Dnmtl with a number of regulatory proteins interactions that modulate Dnmtl methyitransferase activity (darker rectangles) or mediate methylation-independent transcriptional repression mechanisms (lighter rectangles). When Dnmtl represses transcription through its enzymatic activity, it has been described to interact with some proteins PCNA [37] and an oncogenic transcription factor PML-RAR [25]. Note that in the case of the PML-RAR transcription factor, histone deacetylase 1 (HDACl) is also bound to the complex. When Dnmtl represses transcription via methylation-independent pathways, it binds to HDACs either directly [34] or indirectly through other proteins the corepressor DMAPl [33], the retinoblastoma protein, and a gene-specific transcription factor [31].

There are 3 important limitations of probability bounds analysis. The 1st limitation is that, being only bounds on a distribution, a p-box cannot show what distribution is most likely within the box. A p-box provides no shades of gray or 2nd-order information that could tell us which distributions are the most probable. This is essentially the same problem, albeit at a higher level, that intervals had. It may, however, be possible to nest probability bounds analyses to get at the internal structure of the result. It is also often useful to simultaneously conduct a traditional Monte Carlo assessment, which will produce output distributions inside the output p-boxes. Together, these results characterize central and bounding estimates of the output distribution. 

What are some of the consequences of the emphasis on properties External ones such as color, hardness, texture, etc., are all perceptions whose differences are those of degree one shade of gray fades off into another with no clear boundary to be marked. Distinctions tend to be subjective, for there is nothing to count or measure, even if one were philosophically committed to counting and measuring. 

All this is related to the distinction between chemical and physical properties. Physical properties describe what a body is, as it is now. Chemical properties describe what a body can become, how it can react with other identifiable bodies. When bodies mix physically their properties blend properties common to both may be intensified, others are more or less cancelled out or diluted, but the original properties are still there in the mix. Black and white paint can be mixed to any shade of grayness some shades might be distinctive enough to be given names, but there are no sharp boundaries. 

Values are easy to see in black-and-white works, where shades of gray are used to define shapes and distinguish one form from another. 

Calcium carbonate (CaC03) occurs naturally as calcite (density 2.7), a widely distributed mineral. Calcite is a common constituent of sedimentary rocks, as a vein mineral, and as deposits from hot springs and in caves as stalactites and stalagmites. Calcite is white or colorless through shades of gray, red, yellow, green, blue, violet, brown, or even black when charged with impurities streaked, white transparent to opaque. It may occasionally show phosphorescence or fluorescence. 

Carbon black is a black pigment, and lampblack, which has a larger particle size, is used for tinting to produce shades of gray. Carbon black is very opaque and has excellent durability, resistance to all types of chemicals, and light fastness. 

Fig-1 7SREL1 crystal structure (in black and three snapshots (in shades of gray) from MD simulations. Active site residues are shown in sticks to depict their flexibility... 

Need unleashes creativity and resourcefulness. An appropriate and excellent example came to my attention when one of my colleagues forwarded an e-mail from Harry, a general chemistry instructor who had a totally color-blind student who could only distinguish shades of gray but with great accuracy. After some conversations, the student... 

The display hardware requires a high resolution unit (512 x 512 can be acceptable for some use, others may require 1024 x 1024) capable of at least 16 gray shades or colors (the human eye can distinguish 64 shades of gray). Some form of hardcopy is needed. The most appropriate is a photographic device (Dunn Instruments or Matrix - about 10,000). A "pick" device - a light pen, cursor, or tablet - is sometimes desirable to indicate special regions of interest. 

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