Ionospheric electron content at temperate latitudes during the declining phase of the sunspot cycle

Ionospheric electron density during declining phase of sunspot cycle by Faraday effect observation

Wave propagation and earth satellite radio emission studies

Radio propagation studies of the ionosphere using satellite radio beacons are described. The ionosphere is known as a dispersive, inhomogeneous, irregular and sometimes even nonlinear medium. After traversing through the ionosphere the radio signal bears signatures of these characteristics. A study of these signatures will be helpful in two areas: (1) It will assist in learning the behavior of the medium, in this case the ionosphere. (2) It will provide information of the kind of signal characteristics and statistics to be expected for communication and navigational satellite systems that use the similar geometry

Application of Fast Pressure Sensitive Paint in Hypervelocity Flow

The development of fast responding pressure sensitive paints for measurements in high-enthalpy, hypersonic flows is reported. Data are obtained for at plate boundary layers in an impulse facility with typical test gas times on the order of hundreds of microseconds. The fast pressure sensitive paint is found to have the required response time and sufficient signal level to visualize vortical boundary layer structures in a Mach 5.12 freestream. The flow behind protuberance strips with different geometries is evaluated with measurements of the vortex frequency and diameter, as well as breakdown distance. Comparisons with static pressure measurements made using pressure taps show differences of up to a factor of three, and calibration sources as well as an alternative lifetime measurement method remain to be investigated

Information Technology Usage In Accounting Firms: The Best Versus The Rest

The purpose of this paper is to analyze information technology expenditures in public accounting firms from a multi-year sample.  This study also focuses on identifying possible IT spending trends in public accounting firms and attempts to determine if additional spending on IT increased the profitability of these firms

Volume preserving multidimensional integrable systems and Nambu--Poisson geometry

In this paper we study generalized classes of volume preserving multidimensional integrable systems via Nambu--Poisson mechanics. These integrable systems belong to the same class of dispersionless KP type equation. Hence they bear a close resemblance to the self dual Einstein equation. All these dispersionless KP and dToda type equations can be studied via twistor geometry, by using the method of Gindikin's pencil of two forms. Following this approach we study the twistor construction of our volume preserving systems

Prospective randomized trial of ACUSEAL (Gore-Tex) versus Hemashield-Finesse patching during carotid endarterectomy: Early results

Background/PurposeSeveral studies have reported that carotid endarterectomy (CEA) with patch angioplasty produces superior results compared with primary closure. Conventional polytetrafluoroethylene (PTFE) patching has been shown to have results comparable to autogenous vein patching; however, it requires a prolonged hemostasis time. Therefore, many surgeons use collagen-impregnated Dacron patching (Hemashield [HP]). Recently, we reported a satisfactory hemostasis time using the new hemostatic PTFE patch (ACUSEAL by Gore). This study is the first prospective randomized trial comparing the ACUSEAL patch with the HP Finesse patch.Methods200 CEAs were 1:1 randomized into two patch closure groups (ACUSEAL or Finesse). All patients underwent immediate and 1 month postoperative duplex ultrasound studies. Demographic and clinical characteristics were similar in both groups, including the mean operative diameter of the internal carotid artery and length of arteriotomy.ResultsThe overall perioperative ipsilateral stroke rate was 2% (2% ACUSEAL, 2% Finesse; P = 1.0). The perioperative ipsilateral TIA rates were 0% for the ACUSEAL and 2% for the Finesse patch (P = .5). The combined perioperative neurological event (TIA + stroke) rates were 2% for ACUSEAL and 4% for the Finesse (P = .68). The early ≥50% restenosis rate was 0% for ACUSEAL vs 4% for Finesse patching. Two perioperative carotid thromboses were noted with Finesse patching vs none with ACUSEAL patching (P = .50). The combined early morbidity rate (TIA, stroke, and ≥50% restenosis or thrombosis) was 2% for the ACUSEAL patch vs 8% for the Finesse patch (P = .10). The mean hemostasis time for the ACUSEAL and Finesse patches was 5.1 vs 3.7 minutes (P = .01), however, the mean operative times were similar for both groups (P = .61).ConclusionThe perioperative neurological events and overall short-term morbidity associated with CEA when using ACUSEAL or Finesse patches were similar. Both patches have short hemostasis times

ALMA Observations of Asymmetric Molecular Gas Emission from a Protoplanetary Disk in the Orion Nebula

We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of molecular line emission from d216-0939, one of the largest and most massive protoplanetary disks in the Orion Nebula Cluster (ONC). We model the spectrally resolved HCO$^+$ (4--3), CO (3--2), and HCN (4--3) lines observed at 0\farcs5 resolution to fit the temperature and density structure of the disk. We also weakly detect and spectrally resolve the CS (7--6) line but do not model it. The abundances we derive for CO and HCO$^+$ are generally consistent with expected values from chemical modeling of protoplanetary disks, while the HCN abundance is higher than expected. We dynamically measure the mass of the central star to be $2.17\pm0.07\,M_\odot$ which is inconsistent with the previously determined spectral type of K5. We also report the detection of a spatially unresolved high-velocity blue-shifted excess emission feature with a measurable positional offset from the central star, consistent with a Keplerian orbit at $60\pm20\,\mathrm{au}$. Using the integrated flux of the feature in HCO$^+$ (4--3), we estimate the total H$_2$ gas mass of this feature to be at least $1.8-8\,M_\mathrm{Jupiter}$, depending on the assumed temperature. The feature is due to a local temperature and/or density enhancement consistent with either a hydrodynamic vortex or the expected signature of the envelope of a forming protoplanet within the disk.Comment: 19 pages, 12 figures, accepted for publication in A

The Relationship of Limb Apraxia Severity to Motor and Language Deficits

TB

Pseudo-ataxia due to Osteoid Osteoma

Background: Ataxia is diagnosed by typical features on examination suggestive of a cerebellar etiology and can invoke extensive diagnostic testing. Osteoid osteomas (OOs) are benign bone tumors of the lower limbs that occasionally present with focal neurological signs. Case Report: A 3-year-old male presented with apparent progressive gait ataxia and non-specific leg pain. Initial imaging was unremarkable. However, 12 months later, a lesion was identified in the distal right femur, which was found to be an OO. The gait disorder and pain resolved after surgery. Discussion: This case highlights the challenges of diagnosing a gait disorder in young children