Modification of mainframe BOAST II

BOAST II is a black-oil, applied-simulation tool used routinely for performing evaluation and design work in modern petroleum reservoir engineering. Personnel from the Louisiana State University Computer Science Department worked on modifying the mainframe version of this program through the simulation of two-phase flow of slightly compressible fluids in a three-dimensional porous medium. This included the construction of a FORTRAN program that uses 3-D finite elements to approximate the governing equations. The existing finite element code was adapted so that virtually any size of element could easily be incorporated into the solution scheme. This gave increased flexibility and made it possible to utilize mesh refinement techniques. Modifications to the mainframe version also involved the development and integration of radial grid systems suitable for the investigations proposed in the project

Spectral line survey of the ultracompact HII region Mon R2

Ultracompact (UC) HII regions constitute one of the earliest phases in the formation of a massive star and are characterized by extreme physical conditions (Go>10^5 Habing field and n>10^6 cm^-3). The UC HII Mon R2 is the closest one and therefore an excellent target to study the chemistry in these complex regions. We carried out a 3mm and 1mm spectral survey using the IRAM 30-m telescope towards three positions that represent different physical environments in Mon R2: (i) the ionization front (IF) at (0",0"); two peaks in the molecular cloud (ii) MP1 at the offset (+15",-15") and (iii) MP2 at the farther offset (0",40"). In addition, we carried out extensive modeling to explain the chemical differences between the three observed regions. We detected more than thirty different species. We detected SO+ and C4H suggesting that UV radiation plays an important role in the molecular chemistry of this region. We detected the typical PDR molecules CN, HCN, HCO, C2H, and c-C3H2. While the IF and the MP1 have a chemistry similar to that found in high UV field and dense PDRs like the Orion Bar, the MP2 is more similar to lower UV/density PDRs like the Horsehead nebula. We also detected complex molecules that are not usually found in PDRs (CH3CN, H2CO, HC3N, CH3OH and CH3C2H). Sulfur compounds CS, HCS+, C2S, H2CS, SO and SO2 and the deuterated species DCN and C2D were also identified. [DCN]/[HCN]=0.03 and [C2D]/[C2H]=0.05, are among the highest in warm regions. Our results show that the high UV/dense PDRs present a different chemistry from that of the low UV case. Abundance ratios like [CO+]/[HCO+] or [HCO]/[HCO+] are good diagnostics to differentiate between them. In Mon R2 we have the two classes of PDRs, a high UV PDR towards the IF and the adjacent molecular bar and a low-UV PDR which extends towards the north-west following the border of the cloud.Comment: 31 page

Maternal hyperleptinemia is associated with male offspring’s altered vascular function and structure in mice

Children of mothers with gestational diabetes have greater risk of developing hypertension but little is known about the mechanisms by which this occurs. The objective of this study was to test the hypothesis that high maternal concentrations of leptin during pregnancy, which are present in mothers with gestational diabetes and/or obesity, alter blood pressure, vascular structure and vascular function in offspring. Wildtype (WT) offspring of hyperleptinemic, normoglycemic, Lepr db/+ dams were compared to genotype matched offspring of WT-control dams. Vascular function was assessed in male offspring at 6, and at 31 weeks of age after half the offspring had been fed a high fat, high sucrose diet (HFD) for 6 weeks. Blood pressure was increased by HFD but not affected by maternal hyperleptinemia. On a standard diet, offspring of hyperleptinemic dams had outwardly remodeled mesenteric arteries and an enhanced vasodilatory response to insulin. In offspring of WT but not Leprdb/+ dams, HFD induced vessel hypertrophy and enhanced vasodilatory responses to acetylcholine, while HFD reduced insulin responsiveness in offspring of hyperleptinemic dams. Offspring of hyperleptinemic dams had stiffer arteries regardless of diet. Therefore, while maternal hyperleptinemia was largely beneficial to offspring vascular health under astandard diet, it had detrimental effects in offspring fed HFD. These results suggest that circulating maternal leptin concentrations may interact with other factors in the pre- and post-natal environments to contribute to altered vascular function in offspring of diabetic pregnancie

Seasonal Motion in the Annapolis, Maryland GPS Monument

The permanent GPS tracking site at Annapolis, MD shows a 7-mm seasonal signal primarily in its horizontal position. It is suggested that thermal expansion of the pier on which the antenna rests is the source of this motion. A simple numerical model of the pier reproduces the observed motion of the GPS antenna, lending credence to this hypothesis. Although adding an additional level of complexity, this motion is predictable and the site retains it s value for high precision monitoring. Although the arrangement of this GPS site it somewhat uncommon, these results emphasize the importance of the underlying antenna monumentation when measuring crustal motions

A detailed analysis of tropospheric effects on geodetic observations at TMGO

Improvements in geodetic tools are making previously subtle effects significant. Two examples affecting GPS observations are atmospheric loading of the Earth's crust and the tropospheric delays, specifically the wet component. Each measurement, tropospheric delays and site coordinates, requires unambiguous determination of the other to achieve the highest accuracy. Table Mountain Geophysical Observatory (TMGO) is a unique site where a long history of observations from two complementary techniques, GPS and superconducting gravimetry, have been accrued. In particular, the superconducting gravity measurements provide a unique baseline for evaluating GPS vertical estimates over a variety of time frames. Positional estimates for TMGO using these techniques will be compared. Tropospheric effects will be identified and discussed. The ability for GPS to make subdaily, daily, and long term vertical estimates will be evaluated