An EUV Study of the Intermediate Polar EX Hydrae

On 2000 May 5, we began a large multi-wavelength campaign to study the intermediate polar, EX Hydrae. The simultaneous observations from six satellites and four telescopes were centered around a one million second observation with EUVE. Although EX Hydrae has been studied previously with EUVE, our higher signal-to-noise observations present new results and challenge the current IP models. Previously unseen dips in the light curve are reminiscent of the stream dips seen in polar light curves. Also of interest is the temporal extent of the bulge dip; approximately 0.5 in phase, implying that the bulge extends over half of the accretion disk. We propose that the magnetic field in EX Hydrae is strong enough (a few MG) to begin pulling material directly from the outer edge of the disk, thereby forming a large accretion curtain which would produce a very broad bulge dip. This would also result in magnetically controlled accretion streams originating from the outer edge of the disk. We also present a period analysis of the photometric data which shows numerous beat frequencies with strong power and also intermittent and wandering frequencies, an indication that physical conditions within EX Hya changed over the course of the observation. Iron spectral line ratios give a temperature of log T=6.5-6.9 K for all spin phases and a poorly constrained density of n_e=10^10-10^11 cm^-3 for the emitting plasma. This paper is the first in a series detailing our results from this multi-wavelength observational campaign.Comment: 27 pages, 7 figures, accepted for publication in Ap

Comparative NMR study of A_n-bulge loops in DNA duplexes: intrahelical stacking of A, A-A, and A-A-A bulge loops

We have prepared a series of deoxyoligonucleotide duplexes of the sequence d(G-C-A-T-C-G-X-G-C-T-A-C-G)•d(C-G-T-A-G-C-C-G-T-C), in which X represents either one (A), two (A-A), or three (A-A-A) unpaired adenine bases. Using two-dimensional proton and phosphorus NMR spectroscopy, we have characterized conformational features of these bulge-loop duplexes in solution. We find that Watson-Crick hydrogen bonding is intact for all 12 base pairs, including the GC bases that flank the bulge loop. Observation of NOE connectivities in both H_2O and D_2O allows us to unambiguously localize all of the bulged adenine residues to intrahelical positions within the duplex. This is in contrast to an earlier model for multiple-base bulge loops in DNA [Bhattacharyya, A., & Lilley, D. M. J. (1989) Nucleic Acids Res. 17, 6821-68401, in which all but the most 5’ bulged base are looped out into solution. We find that insertion of two or three bases into the duplex results in the disruption of specific sequential NOEs for the base step across from the bulge loop site on the opposite strand. This disruption is characterized by a partial shearing apart of these bases, such that certain sequential NOEs for this base step are preserved. We observe a downfield-shifted phosphorus resonance, which we assign in the A-A-A bulge duplex to the 3‘ side of the last bulged adenine residue. Proton and phosphorus chemical shift trends within the A,-bulge duplex series indicate that there is an additive effect on the structural perturbations caused by additional unpaired bases within the bulge loop. This finding parallels previous observations [Bhattacharyya, A., & Lilley, D. M. J. (1989) Nucleic Acids Res. 17, 6821-6840; Hsieh, C.-H., & Griffith, J. D. (1989) Proc. Nutl. Acud. Sci. U.S.A. 86,4833-48371 on the magnitude of the induced bending of DNA duplexes by multiple-base bulge loops

Comparative NMR study of A_n-bulge loops in DNA duplexes: intrahelical stacking of A, A-A, and A-A-A bulge loops

We have prepared a series of deoxyoligonucleotide duplexes of the sequence d(G-C-A-T-C-G-X-G-C-T-A-C-G)•d(C-G-T-A-G-C-C-G-T-C), in which X represents either one (A), two (A-A), or three (A-A-A) unpaired adenine bases. Using two-dimensional proton and phosphorus NMR spectroscopy, we have characterized conformational features of these bulge-loop duplexes in solution. We find that Watson-Crick hydrogen bonding is intact for all 12 base pairs, including the GC bases that flank the bulge loop. Observation of NOE connectivities in both H_2O and D_2O allows us to unambiguously localize all of the bulged adenine residues to intrahelical positions within the duplex. This is in contrast to an earlier model for multiple-base bulge loops in DNA [Bhattacharyya, A., & Lilley, D. M. J. (1989) Nucleic Acids Res. 17, 6821-68401, in which all but the most 5’ bulged base are looped out into solution. We find that insertion of two or three bases into the duplex results in the disruption of specific sequential NOEs for the base step across from the bulge loop site on the opposite strand. This disruption is characterized by a partial shearing apart of these bases, such that certain sequential NOEs for this base step are preserved. We observe a downfield-shifted phosphorus resonance, which we assign in the A-A-A bulge duplex to the 3‘ side of the last bulged adenine residue. Proton and phosphorus chemical shift trends within the A,-bulge duplex series indicate that there is an additive effect on the structural perturbations caused by additional unpaired bases within the bulge loop. This finding parallels previous observations [Bhattacharyya, A., & Lilley, D. M. J. (1989) Nucleic Acids Res. 17, 6821-6840; Hsieh, C.-H., & Griffith, J. D. (1989) Proc. Nutl. Acud. Sci. U.S.A. 86,4833-48371 on the magnitude of the induced bending of DNA duplexes by multiple-base bulge loops

Comprehensive Management of the Paranasal Sinuses in Patients Undergoing Endoscopic Endonasal Skull Base Surgery.

OBJECTIVE: The endonasal route often provides the most direct and safe approach to skull base pathology. In this article we review the literature with regard to management of the paranasal sinuses in the setting of skull base surgery. METHODS: We describe our institutional experience and review the literature of concurrent management of the sinusitis in patients undergoing endoscopic skull base surgery. RESULTS: Patients should be optimized preoperatively to ensure the endonasal route is a safe corridor to enter the intracranial cavity. Often the paranasal sinuses can be surgically addressed at the same time as endoscopic skull base surgery. We describe the technical details of management of the paranasal sinuses when addressing skull base pathology. CONCLUSIONS: Careful management of the paranasal sinuses throughout the peri-operative course is paramount to optimizing sinonasal function and safety

A High Fat Diet Increases Bone Marrow Adipose Tissue (MAT) But Does Not Alter Trabecular or Cortical Bone Mass in C57BL/6J Mice

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111767/1/jcp24954.pd

Massive Electrodynamics and Magnetic Monopoles

Including torsion in the geometric framework of the Weyl-Dirac theory we build up an action integral, and obtain from it a gauge covariant (in the Weyl sense) general relativistic massive electrodynamics. Photons having an arbitrary mass, electric, and magnetic currents (Dirac's monopole) coexist within this theory. Assuming that the space-time is torsionless, taking the photons mass zero, and turning to the Einstein gauge we obtain Maxwell's electrodynamics.Comment: LaTex File, 9 pages, no figure

Rapid Imaging of Earthquake Ruptures with Combined Geodetic and Seismic Analysis

Rapid determination of the location and extent of earthquake ruptures is helpful for disaster response, as it allows prediction of the likely area of major damage from the earthquake and can help with rescue and recovery planning. With the increasing availability of near real-time data from the Global Positioning System (GPS) and other global navigation satellite system receivers in active tectonic regions, and with the shorter repeat times of many recent and newly launched satellites, geodetic data can be obtained quickly after earthquakes or other disasters. We have been building a data system that can ingest, catalog, and process geodetic data and combine it with seismic analysis to estimate the fault rupture locations and slip distributions for large earthquakes