. DISCLAIMER • Thi» book wm preoeicd at in account ol work tponured by an agency ol the United Slaloi Government. Neither the United Stale* Government nor any agency thereof, nor any ol their ernpluyeei, matatenv warranty, eaurra or Implied, or auumei any letial liability or retpaniiollllv tot the accuracy, cnmpleleneu, ot uwlulneu rjl any Information, apparatus, ptoduct, or proceu dlKloud, or reprnsnla that 111 u»» rwutd not Infringe privately owned rlghu. Reference herein to any tpeclllc commercial prtxhjcl, proceu, or nrvlco by trade name, tredemarlt, manufacturer, or otherwlw, doei not necmtarlly conllltute or Imply 111 endotiement, recommendation, or favoring by the United Slates Government or any agency thereol. 3 , where Q is the flow rate, ah is the difference in hydraulic head, C is a constant that depends on the flow geometry and fluid properties, and 2b is the fracture aperture. The validity of this law for flow in a closed fracture where the surfaces are in contact and the aperture is being decreased under stress has been investigated at room temperature using homogeneous samples of granite, basalt, and marble. Tension fractures were artificially induced and the labor atory setup used radial as well as straight flow geometries. Apertures ranged from 250 ym down to 4 ym, which was the minimum size that could be attained under a normal stress of 20 MPa. Preliminary Report on Geophysical and Mechanical Borehole Measurements at

Type 2 diabetes mellitus (T2DM) is complex metabolic disease that arises as a consequence of interactions between genetic predisposition and environmental triggers. One recently described environmental trigger associated with development of T2DM is disturbance of circadian rhythms due to shift work, sleep loss, or nocturnal lifestyle. However, the underlying mechanisms behind this association are largely unknown. To address this, the authors examined the metabolic and physiological consequences of experimentally controlled circadian rhythm disruption in wild-type (WT) Sprague Dawley and diabetes-prone human islet amyloid polypeptide transgenic (HIP) rats: a validated model of T2DM. WT and HIP rats at 3 months of age were exposed to 10 weeks of either a normal light regimen (LD: 12:12-h light/dark) or experimental disruption in the light-dark cycle produced by either (1) 6-h advance of the light cycle every 3 days or (2) constant light protocol. Subsequently, blood glucose control, beta-cell function, beta-cell mass, turnover, and insulin sensitivity were examined. In WT rats, 10 weeks of experimental disruption of circadian rhythms failed to significantly alter fasting blood glucose levels, glucose-stimulated insulin secretion, beta-cell mass/turnover, or insulin sensitivity. In contrast, experimental disruption of circadian rhythms in diabetes-prone HIP rats led to accelerated development of diabetes. The mechanism subserving early-onset diabetes was due to accelerated loss of beta-cell function and loss of beta-cell mass attributed to increases in beta-cell apoptosis. Disruption of circadian rhythms may increase the risk of T2DM by accelerating the loss of beta-cell function and mass characteristic in T2DM.

The general three-dimensional equations for pore pressure, stress, and strain in a homogeneous porous medium with compressible grains are used to derive expressions for the response of fluid presstire to the stress changes due to earth tides and barometric loading effects. The analysis constitutes a generalization of earlier derivations. The formation is assumed to be of large extent laterally so that horizontal flow may be neglected. It is shown that vertical flow induced by the pore pressure changes can be analyzed by means of a diffusion equation. An expression for the specific storage coefficient is derived which is valid if horizontal deformations are negligible and which includes the effect of the compressibility of the solid grains. Measurements of earth tide and barometric effects constitute two in situ tests of bulk formation properties. Such measurements can therefore make an important contribution to the characterization of the hydraulic and elastic properties of a particular formation.

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