Alternative Lighting

UV and TR lighting is a common nondestructive tool used in the analysis of questioned documents. The principle behind most of these techniques is fluorescence. Many inks fluoresce in the visible region or infrared region of the spectrum when they are exposed to ultraviolet or visible light, respectively. In addition, many printing inks, such as those used in currency, have fluorescent security features that are not easily duplicated by counterfeiters. Collectively, these techniques are called 

In October 2001, a person or persons sent anttirax through the mail, resulting in seven deaths, thousands of exposures, and major disruptions. The anttirax powder was contained in an envelope along with a handwritten letter. The envelope and letter were invaluable physical evidence, but analysis had to wait months while methods were developed to open and sterilize the evidence before traditional forensic examinations such as ink analysis could ev en begin. 

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Lasers (qv) and other high intensity or alternative light sources are usefiil in crime laboratories to visualize latent fingerprints, seminal fluid stains, obhterated writings, and erasures, and to aid in specialized photographic work. Infrared and ultraviolet light sources are also used to view items of evidence. 

Figure 14.10 A muscle viewed under the microscope is seen to contain many myofibrils that show a cross-striated appearance of alternating light and darkbands, arranged in repeating units called sarcomeres. The dark bands comprise myosin filaments and are interupted by M (middle) lines, which link adjacent myosin filaments to each other.

The cells of the latter three types contain only a single nucleus and are called myocytes. The cells of skeletal muscle are long and multinucleate and are referred to as muscle fibers. At the microscopic level, skeletal muscle and cardiac muscle display alternating light and dark bands, and for this reason are often referred to as striated muscles. The different types of muscle cells vary widely in structure, size, and function. In addition, the times required for contractions and relaxations by various muscle types vary considerably. The fastest responses (on the order of milliseconds) are observed for fast-twitch skeletal... 

Internally, muscle fibers are highly organized. Each fiber contains numerous myofibrils — cylindrical structures that also lie parallel to the long axis of the muscle. The myofibrils are composed of thick filaments and thin filaments. It is the arrangement of these filaments that creates alternating light and dark bands observed microscopically along the muscle fiber. Thus, skeletal muscle is also referred to as striated muscle. 

ESTUARINE SEDIMENTS Sterilized under alternating light and dark No degradation in 28 days 2... 

Alternatively, light is consumed and the reaction progress is possible only under continuous light absorption this option, called catalyzed photolysis, includes photoassisted generation of a reactive form of substrate or photocatalyst. In the former the process is called catalyzed photochemical reaction, whereas in the latter either catalyst activation may lead to formation of catalyst or photoinitiator, which initiates chemical transformations but is consumed within a reaction cycle, or the catalyst reacts with substrate in its excited state (photosensitization) in both cases... 

The prices of natural gas or an alternate light hydrocarbon reformer feed, resid, and electricity are assumed to apply to all geographical locations in the U. S. However, delivered-coal prices vary from one geographical location to another. Mine-mouth coal prices are affected by mining costs and coal quality. Transportation costs for moving the coal to manufacturing sites have been assumed to be proportional to the transportation distance. 

Figure 4. Longitudinal slice through 25 cm high stalagmite showing alternating light and dark hands. White Arch Cave, Norway. Specimen loaned hy S.-E. Lauritzen.

Figure 6.2 Vertical section through a stream crust colonised by the cyanobacterium Phormidium incrustatum. The slightly undulose nature of the upper surface is caused by the coalescence of adjacent colonies. The alternating light and dark layers are probably seasonal and suggest a deposition rate of about 1 mm yr1. Harrietsham, Kent. Scale bar 5 mm.

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