It is reasonable to treat patients with type 1 hepatorenal syndrome with midodrine and octreotide

A critical appraisal and clinical application of Esrailian E, Pantangco ER, Kyulo NL, Hu KQ, Runyon BA. Octreotide/midodrine therapy significantly improves renal function and 30-day survival in patients with type 1 hepatorenal syndrome. Dig Dis Sci. 2007;52(3):742-748. doi: 10.1007/s10620-006-9312-

Report on the electrophoretic and morphometric studies conducted at the Inter-American Tropical Tuna Commission from 1969 to 1978

Knowledge of the population structure of an exploited stock is necessary for the effective management of a fishery. For this reason the Inter-American Tropical Tuna Commission (IATTC) has sponsored numerous genetic, morphometric, and migration studies of yellowfin, Thunnus albacares, and skipjack, Katswonus pelamis, in a concerted effort to determine the structure of these stocks in the eastern Pacific Ocean. (PDF contains 171 pages.

3-D Geostatistical Seismic Inversion With Well Log Constraints

Information about reservoir properties usually comes from two sources: seismic data and well logs. The former provide an indirect, low resolution image of rock velocity and density. The latter provide direct, high resolution (but laterally sparse) sampling of these and other rock parameters. An important problem in reservoir characterization is how best to combine these data sets, allowing the well information to constrain the seismic inversion and, conversely, using the seismic data to spatially interpolate and extrapolate the well logs. We develop a seismic/well log inversion method that combines geostatistical techniques for well log interpolation (i.e., kriging) with a Monte Carlo search method for seismic inversion. We cast our inversion procedure in the form of a Bayesian maximum a posteriori (MAP) estimation in which the prior is iteratively modified so that the algorithm converges to the model that maximizes the likelihood function. We follow the approach used by Haas and Dubrule (1994) in their sequential inversion algorithm. Kriging is applied to the well data to obtain velocity estimates and their covariances for use as a priori constraints in the seismic inversion. Inversion of a complete 3-D seismic section is performed one trace at a time. The velocity profiles derived from previous seismic traces are incorporated as "pseudo well logs" in subsequent applications of kriging. Our version of this algorithm employs a more efficient Monte Carlo search method in the seismic inversion, and moves sequentially away from the wells so as to minimize the kriging variance at each step away from the inverted wells. Numerical experiments with synthetic data demonstrate the viability of our seismic/ well data inversion scheme. Inversion is then performed on a real 3-D data set provided by Texaco.Texas CompanyMassachusetts Institute of Technology. Borehole Acoustics and Logging ConsortiumMassachusetts Institute of Technology. Earth Resources Laboratory. Reservoir Delineation Consortiu

Simultaneous least squares deconvolution and kriging using conjugate gradients

Least squares deconvolution is a method used to sharpen tomographic images of the earth by undoing the bandlimiting effects imposed by a seismic wavelet. Kriging is a method used by geoscientists to extrapolate and interpolate sparse data sets. These two methodologies have traditionally been kept separate and viewed as unrelated fields of research. We demonstrate the connection between these methods by deriving them both as examples of linear inversion. By posing the methods in this way we can define a joint inverse problem in which observed values of reflectivity in wells are used to improve deconvolution, and, conversely, seismic data is used to help extrapolate well data. Solving this joint problem involves the solution of large sparse sets of linear equations. Due to the structure of the problem, the conjugate gradients method is ideal to perform the solution. Preliminary results show that convergence to a solution for a 3-D problem is fast and accurate, requiring only a few iterations. This methodology can be of great use to interpreters by sharpening the post stack image as well as helping to tie seismic data to wells

From the editors

Introduction to Volume 2, Issue 2 by the new Senior Student Editors

Preparing South Africa for Information Society 'E-Services': The Significance of the VANS Sector

New Value-Added Network Services (VANS) provide the foundation for the wide variety of applications (e-commerce, e-government, e-education, etc.,) that will make-up the e-economy in new information societies. Internet services are only a part of the VANS sector. The development of VANS is influenced primarily by three factors – technological improvements, government policies/ regulations, and the market structure of the VANS sector. South Africa has announced clear information society policies, but has not yet implemented them. Although the national fixed telecom network has experienced declining coverage in recent years, for those connected, the network is fully digitalised and makes increasing use of Internet Protocol. Technologically, South Africa is well prepared to be a leader in VANS development. However, its policy and regulation arena has been a site of continuous conflict and indecision, which has resulted in VANS development being restricted rather than promoted by government policy. Telkom’s aggressive activity in attempting to maximise its service exclusivities has restricted VANS development even further. Telkom’s exclusivity period under the government’s “managed liberalisation” policy ended 7 May 2002. If South Africa is to see its information society and e-economy policies implemented, it will have to establish, and implement through strong regulation, a commitment to promoting an innovative VANS sector. The forthcoming convergence legislation provides an opportunity to do so

Once daily versus conventional dosing of pH-dependent mesalamine long-term to maintain quiescent ulcerative colitis: Preliminary results from a randomized trial

Sunanda Kane1, William Holderman2, Peter Jacques2, Todd Miodek31Mayo Clinic College of Medicine, Rochester, MN, USA; 2Digestive Health Specialists, Tacoma, WA, USA; 3University of Chicago, Chicago, IL, USABackground and Aims: Multiple studies have demonstrated the efficacy of aminosalicylates in maintaining remission in ulcerative colitis (UC). A newer formulation of mesalamine can be administered once daily. We aimed to examine the efficacy and tolerability of pH-dependent mesalamine for long-term maintenance, and compare the rates of medication consumption between groups over a prolonged period.Methods: Subjects whose UC had been quiescent for at least 4 months, and who had been receiving mesalamine for maintenance only, were randomized to once daily or conventional dosing for 12 months. Disease activity and medication consumption was assessed every 3 months. The primary endpoint was the percentage of those with quiescent disease at 12 months.Results: We enrolled 20 patients, 12 to once daily and 8 to conventional dosing. Six of the 12 patients (50%) in the once daily group compared with 5 of the 8 patients (62.5%) in the conventional group experienced a flare (p = 0.31). Only 5 of the 12 (42%) patients in the once daily group were adherent compared with 3 of 8 patients (37.5%) in the conventional dosing group (p = NS). Median amount consumed in the once daily group was 63% (range 0%–100%) and in the conventional group 55% (range 0%–100%), (p > 0.5). None of the adherent subjects in the once daily group experienced a flare, while 6 out of 7 (86%) who were non-adherent experienced a flare (p < 0.01). In the conventional dosing group, 1 in 3 adherent patients (33%) experienced a fl are compared with 4 out of 5 (80%) in the non-adherent group (p < 0.01).Conclusion: Adherence, rather than medication regimen, appeared to be important in disease outcome at 12 months.Keywords: ulcerative colitis, mesalamine, aminosalicylates, remissio

Geostatistical Seismic Inversion Using Well Log Constraints

Information about reservoir properties usually comes from two sources: seismic data and well logs. The former provide an indirect, low resolution image of rock velocity and density. The latter provide direct, high resolution (but laterally sparse) sampling of these and other rock parameters. An important problem in reservoir characterization is how best to combine these data sets, allowing the well information to constrain the seismic inversion and, conversely, using the seismic data to spatially interpolate and extrapolate the well logs. We have developed a seismic/well log inversion method that combines geostatistical methods for well log interpolation (i.e., kriging) with a Monte Carlo search technique for seismic inversion. Our method follows the approach used by Haas and Dubrule (1994) in their sequential inversion algorithm. Kriging is applied to the well data to obtain velocity estimates and their variances for use as a priori constraints in the seismic inversion. Further, inversion of a complete 2-D seismic section is performed one trace at a time. The velocity profiles derived from previous seismic traces are incorporated as "pseudo well logs" in subsequent applications of kriging. Our version of this algorithm employs a more efficient Monte Carlo search algorithm in the seismic inversion step, and moves progressively away from the wells so as to minimize the kriging variance at each step. Numerical experiments with synthetic data demonstrate the viability of our seismic/well data inversion scheme.Massachusetts Institute of Technology. Borehole Acoustics and Logging ConsortiumMassachusetts Institute of Technology. Earth Resources Laboratory. Reservoir Delineation Consortiu