Becke test

Beck Depression Inventory. The Beck Depression Inventory (Beck) test may be used to measure the depth of depression as a rapid screen for depressed patients. It is a self-rating scale of 21 items (13 in a shortened form), with each item rated on a four-point scale. It measures the immediate present and has been used in antidepressant medicine trials. The original 21-item scale can be completed in about 10 minutes and the test is able to discriminate between anxiety and depression. No subtests are present in the Beck. 

BECKE TEST. A microscope of moderate or high magnification is used to compare the indices of refraction of two contiguous minerals for of a mineral and a mounting medium or immersion liquid), in a thin section or other mount. When the two substances differ substantially in refractive index, they are separated by a bright line, called the Becke line. The line moves toward the less refractive of two materials when the tube of the microscope is lowered. 

Another test to determine whether the particle or medium has the higher n is the Becke test. The Becke line is a halo around the particle. As the objective is raised or the stage is lowered, the Becke line will move into the medium or particle having the higher n. As the objective is lowered or the stage is raised, the Becke line will enter the medium or particle having the lower n. 

One of the more useful methods is the Becke test. Becke noticed that when the microscope is focused up and down a bright halo near the boundary of a particle moves in and out. The halo will always move toward the higher refractive index as the focus is raised and toward the lower refractive index as the focus is lowered. Thus if the particle has a refractive index higher than the liquid, the Becke line will move from outside the boundary to the inside as the focus is raised and vice versa. Figures 4 and 5 show the bright Becke line outside and inside the boundary, respectively. 

K. Beck, Test-Driven Development By Example. Addison-Wesley, Boston, MA, 2003. 

Becke test n. The method for determining refractive index of a transparent particle by noting the direction in which the Becke line moves. The halo (Becke lines) will always move to the higher refractive index medium as the focus is raised. The halo crosses the boundary into the lower refractive index medium when the microscope is focused down. The particle must be illuminated with a narrow cone of axial light obtained by closing the aperture diaphragm of the condenser to a small aperture. Nesse WD (2003) Introduction to optical mineralogy. Oxford University Press, New York. 

The depth of cut involved in precoat filtration is a veiy important economic factor. There is some disagreement as to the method required to accurately predic t the minimum permissible depth of cut. Some investigators maintain that the depth of cut can be evaluated only in a quah-tative manner during bench-scale tests by judging whether the process solids remain on the surface of the precoat beck This being so, they indicate that it is necessaiy to run a continuous pilot-plant test to determine the minimum permissible depth of cut. The use of a continuous pilot-plant filter is a veiy desirable approach and will provide accurate information under a variety of operating conditions. 

Fig. 8.101 Bend lest using a tensile testing machine (after Beck et al. )...

Neumann and Handy, 1996, implemented the recent B95 correlation functional and tested it on a G2 subset. This functional was originally proposed by Becke and obeys... 

Schmider, H. L., Becke, A. D., 1998a, Optimized Density Functionals from the Extended G2 Test Set , J. Chem. 

Beck, T. L., Quantum path integral extension of Widom s test particle method for chemical potentials with application to isotope effects on hydrogen solubilities in model solids, J. Chem. Phys. 1992, 96, 7175-7177... 

Noyce, J. R., Moore, D. T., Sherwood, J. D., Daniel, P. R., Beck, J. N. and Kuroda, P. K. (1973). Fallout from nuclear weapons testing and interhemispheric transport of nuclear debris, Health Phys. 25, 109. 

Other taxometrics research has evaluated the validity of theoretical psychopathological subtypes. For example, Haslam and Beck (1994) used CCK procedures to test whether five proposed subtypes of major depression (e.g., endogenous, sociotropic, autonomous) reflect underlying categories. Again, because these theoretical subtypes of depression are not necessarily represented in the DSM, they do not speak directly to psychiatric nosology. 

Support for a depression taxon comes primarily from subtyping studies. First, Haslam and Beck (1994) tested the taxonicity of several theoretical... 

Bullard, R. W. Shumake, S. A. "Vertebrate Pest Control and Managanent Materials (ASTM STP 680)" Beck, J. R., Ed. American Society For Testing and Materials, Special Technical Publication No. 680, 1979 pp. 178-187. 

The first way has been followed in what has become known as Car-Parrinello molecular dynamics (CPMD) (9). A solute and 60-90 solvent molecules are considered to represent the system, and the QM calculations are performed with density functionals, usually of generalised gradient approximation type (GGA), such as the Becke-Lee-Young-Parr (BLYP) (10) or the Perdew-Burke-Enzerhofer (PBE) (11,12) functionals. It is clear that the semiempirical character of concurrent density functional theory (DFT) methods and the use of these simple functionals imply a number of error sources and do not really provide a method-inherent control procedure to test the reliability of results. Recently it has been shown that these functionals even do not enable a correct description of the solvent water itself, as at ambient temperature they will describe water not as liquid but as supercooled system... 

If we adopt the assumption tliat the expectation value curve in Figure 8.2 is a line, simple geometry allows us to determine that z = 0.5. Use of this value defines a so-called half-and-half (H H) metliod. Using LDA exchange-correlation, Becke showed that the H H approach had an error of 6.5 kcal mol" over a subset of the G3 enthalpy of formation test set mentioned in Chapter 7. This compared quite favorably with the GGA method BPW91, which had an error of 5.7 kcal mol" over the same set. 

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