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The fracture systems intersecting Eocene chalk formations in the Negev desert, Israel, and their hydraulic properties were characterized using a variety of geologic and hydrologic techniques. These included identification of the prevailing directions of fracture systems in outcrops, in cores retrieved from inclined coreholes, in coreholes using video logs, and in trenches. The orientation and inclination of these fracture systems were determined, and evidence of ground water flow on the fracture surfaces was described and ranked. Their hydraulic conductivity was determined through slug and pumping tests performed at discrete intervals. Temperature, electrical conductivity, caliper, gamma and heat-pulse logs were conducted in the same coreholes. The results from the logs, tests, and core descriptions were compared to identify reliable and cost-effective tools for investigating the hydraulic characteristics of fracture systems. We concluded that in the study area: (1) fracture mapping in outcrops and coreholes (including downhole video and caliper logs) must be supplemented by hydraulic testing of the mapped fracture sets in the coreholes; (2) inclined coreholes provide information regarding the orientation of the hydraulically active fracture systems that cannot be obtained from vertical boreholes; (3) hydraulic testing of unpacked holes provides a reasonable estimate of the maximum hydraulic conductivity; and (4) the hydraulic conductivity distribution with depth is log normal and all significant ground water flow takes place within the upper 25 m.

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A 22-residue peptic peptide from rabbit myelin basic protein (r-MBP) that spans the triprolyl sequence has been studied in aqueous solution by high-resolution two-dimensional (2-D) proton NMR. The resonances are assigned with the help of 2-D correlated spectroscopy, pH titration, one-dimensional (1-D) spin-decoupling techniques, and the spectrum of a phosphorylated form of the peptide. The a-CH resonances of Pro-7, Thr-6, and Thr-9 (but not of Thr-20) are markedly shifted downfield with respect to values in small unstructured peptides; similar shifts are observed in the complete r-MBP, suggesting that peptide and protein have similar O n e of the most interesting problems presented by myelin basic protein (MBP) has been elucidation of the structural and functional roles of the sequence of three proline residues (Pro-Pro-Pro) that occurs at positions 99-101 in the primary structures in all species so far examined (Mendz et al., 1983). When the triprolyl sequence in MBP was discovered, it was suggested that it might be the site of a "hairpin bend", which would bring the unique methylated arginine at site 108 opposite the pair of phenylalanine residues at 90-91, resulting in a hydrophobic interaction stabilizing the bend (Brostoff & Eylar, 1971). Possible functions of such a bend region in the protein were discussed (Carnegie, 1971a,b;Boggs & Moscarello, 1978). The first NMR experiment that provided evidence concerning this question was a high-resolution proton study in aqueous solution (Littlemore, 1978), which showed that the resonance of the CH3 groups of Arg-108 has exactly the same chemical shift in MBP as in the 2-[(4-hydroxyphenyl)azo]-benzenesulfonate monohydrate salt of methylarginine; consequently, there is no observable evidence for a ring-current effect due to nearby phenylalanines. This paper presents results of an investigation by 'H and 13C NMR spectroscopy in aqueous solution of a peptide r-(91-112) comprising residues 91-112 of rabbit (r) MBP:' Phe-Ly s-Asn-Ile-Val-Thr-Pro-Arg-Thr-Pro-Pro-