SUBJECTS flint

Boeda et al. (1996) identified bitumen on a flint scraper and a Levallois flake, discovered in Mousterian levels (about 40 000 BP) at the site of Umm el Tlel in Syria. The occurrence of polyaromatic hydrocarbons such as fluoranthene, pyrene, phenanthrenes and chrysenes suggested that the raw bitumen had been subjected to high temperature. The distribution of the sterane and terpane biomarkers in the bitumen did not correspond to the well-known bitumen occurrences in these areas. In other studies of bitumen associated with a wide variety of artefacts of later date, especially from the 6th Millennium BC onwards, molecular and isotopic methods have proved successful in recognizing different sources of bitumen enabling trade routes to be determined through time (Connan et al., 1992 Connan and Deschesne, 1996 Connan, 1999 Harrell and Lewan, 2002). 

A wide variety of glasses possessing different indices of refraction is available for use in the visible region. For example, a light crown glass has an index of refraction of 1.5170 at 5893 A and a dense flint glass has an index of refraction of 1.6499 at the same wavelength. Salt (NaCl) crystals are used frequently since they are transparent in the infrared, but they are subject to severe deterioration unless carefully protected from moisture. 

Duncan SH, Belenguer A, Holtrop G, Johnstone AM, Flint HJ, Lobley GE. Reduced dietary intake of carbohydrates by obese subjects results in decreased concentrations of butyrate and butyrate-producing bacteria in feces. Appl Environ Microbiol. 2007 73 1073-1078. 

The program of viral gene expression that defines a productive infection has been subject to intense scrutiny, but will be described only briefly here the interested reader is referred to Tooze (1980), Ziff (1980), or Flint (1982) for more detailed information. Early genes, defined as those expressed prior to the onset of viral DNA replication, are expressed as six transcriptional units ElA, ElB, E2, E3, E4,... 

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