Issues in providing a reliable multicast facility

Issues involved in point-to-multipoint communication are presented and the literature for proposed solutions and approaches surveyed. Particular attention is focused on the ideas and implementations that align with the requirements of the environment of interest. The attributes of multicast receiver groups that might lead to useful classifications, what the functionality of a management scheme should be, and how the group management module can be implemented are examined. The services that multicasting facilities can offer are presented, followed by mechanisms within the communications protocol that implements these services. The metrics of interest when evaluating a reliable multicast facility are identified and applied to four transport layer protocols that incorporate reliable multicast

Rapid Steel Tooling Via Solid Freeform Fabrication

With increasing part complexity and requirements for long production runs, tooling has become an expensive process that requires long lead times to manufacture. This lengthens the amount oftime from "art to part". Rapid tooling via stereolithography (SLA), filled epoxies, etc. have been stopgap measures to produce limited prototyping runs from (10 to 500 parts). This gives poor dimensional analysis and does not allow for limited production runs of 1000+ parts. The method ofproducing prototype tooling with a powdered metal process has been developed that produces tooling with a hardness greater than 35 HRC and total shrinkage less than 0.5%. This tooling process manufactures production ready tooling that will perform extended cycle runs (100,000+). Manufacturing ofthis tooling takes 1 to 2 weeks and will compare favorably with production grade steel tooling. Originals drawn in 3D CAD can be used to prototype the master that will allow for the production ofthe rapid metal tool set. process starts with a rapid prototyped model made by whatever process is desired or a machined master. For this paper a Sander's Model Maker II® rapid prototyping machine was used to fabricate the model. After the model ofthe tool set is made, a silicone rubber negative is cast around that model. After the silicone rubber model is made, a heated slurry ofmetal powders and polymers is poured into the mold to create the green tool set. The tool set is left to cool, and then removed from the silicone rubber mold. The tool set is then debound and sintered to produce a final tool set with properties approaching hardened tool steel.Mechanical Engineerin

Old and Young X-ray Point Source Populations in Nearby Galaxies

We analyzed 1441 Chandra X-ray point sources in 32 nearby galaxies. The total point-source X-ray luminosity L_XP is well correlated with B, K, and FIR+UV luminosities of spiral host galaxies, and with the B and K luminosities for ellipticals. This suggests an intimate connection between L_XP and both the old and young stellar populations, for which K and FIR+UV luminosities are proxies for the galaxy mass M and star-formation rate SFR. We derive proportionality constants 1.3E29 erg/s/Msol and 0.7E39 erg/s/(Msol/yr), which can be used to estimate the old and young components from M and SFR, respectively. The cumulative X-ray luminosity functions for the point sources have quite different slopes for the spirals (gamma ~= 0.5-0.8) and ellipticals (gamma ~= 1.4), implying *the most luminous point sources dominate L_XP* for the spirals. Most of the point sources have X-ray colors that are consistent with either LMXBs or Ultraluminous X-ray sources (ULXs a.k.a. IXOs) and we rule out classical HMXBs (e.g. neutron-star X-ray pulsars) as contributing much to L_XP. Thus, for spirals, the ULXs dominate L_XP. We estimate that >~20% of all ULXs found in spirals originate from the older (pop II) stellar populations, indicating that many of the ULXs that have been found in spiral galaxies are in fact pop II ULXs, like those in elliptical galaxies. The linear dependence of L_XP on the SFR argues for either a steepening in the X-ray luminosity function of the young (pop I) X-ray source population at L_X >~10^(38.5-39) erg/s, or a decreasing efficiency for producing all types of young X-ray point sources as the galaxy SFR increases.Comment: 33 pages AASTEX, ApJ accepted. Please download full version with figures from http://www.pha.jhu.edu/~colbert/chps_accepted.p

The Relationship of Worry About Hypoglycemia With Diabetes-specific and Typical Youth Behavior Among Emerging Adults With Type 1 Diabetes

PURPOSE: Little is known about the relationship of worry about hypoglycemia with diabetes-specific and typical youth behaviors among emerging adults with type 1 diabetes. This study's purpose was to examine the relationship among worry about hypoglycemia, diabetes management, and glycemic control within the context of alcohol use, hypoglycemia-related weight control behaviors, depressive symptoms, and impulse control among emerging adults with type 1 diabetes. RESEARCH DESIGN AND METHODS: The sample was 181 emerging adults with type 1 diabetes who were part of a larger study. Path analysis was used to test associations among worry about hypoglycemia, diabetes management, hypoglycemia-related weight control behaviors (WCB), alcohol use, impulse control, depressive symptoms, and glycemic control. RESULTS: Path model fit and modification indices suggested that a feedback loop between worry about hypoglycemia and diabetes management should be incorporated into the original model. Youth with fewer depressive symptoms reported fewer hypoglycemia-related WCB and less worry about hypoglycemia; those with higher impulse control had less alcohol use and better diabetes management; those with lower alcohol use had more worry about hypoglycemia; and better glycemic control was associated with better diabetes management. CONCLUSIONS: Health care professionals need to understand how multiple factors related to worry about hypoglycemia and diabetes management interact in emerging adults. In the context of depressive symptoms, impulse control, alcohol use, and hypoglycemia-related WCB, the path model results suggest several potential avenues for intervening to improve glycemic control in emerging adults

Fe XXV and Fe XXVI Diagnostics of the Black Hole and Accretion Disk in Active Galaxies: Chandra Time-Resolved Spectroscopy of NGC 7314

We report the detection of Fe XXV and Fe XXVI $K\alpha$ emission lines from a Chandra HETGS observation of the Seyfert~1 galaxy NGC 7314, made simultaneously with RXTE. The lines are redshifted (cz ~ 1500 km/s) relative to the systemic velocity and unresolved. We argue that the lines originate in a near face-on (<7 degrees) disk having a radial line emissivity flatter than r^-2. Line emission from ionization states of Fe in the range ~Fe I up to Fe XXVI is observed. The ionization balance of Fe responds to continuum variations on timescales less than 12.5 ks, supporting an origin of the lines close to the X-ray source. We present additional, detailed diagnostics from this rich data set. These results identify NGC 7314 as a key source to study in the future if we are to pursue reverberation mapping of space-time near black-hole event horizons. This is because it is first necessary to understand the ionization structure of accretion disks and the relation between the X-ray continuum and Fe K line emission. However, we also describe how our results are suggestive of a means of measuring black-hole spin without a knowledge of the relation between the continuum and line emission. Finally, these data emphasize that one {\it can} study strong gravity with narrow (as opposed to very broad) disk lines. In fact narrow lines offer higher precision, given sufficient energy resolution.Comment: Accepted for publication in the Astrophysical Journal. 30 pages, six figures, five of them color. Abstract is abridge

Very Extended X-ray and H-alpha Emission in M82: Implications for the Superwind Phenomenon

We discuss the properties and implications of a 3.7x0.9 kpc region of spatially-coincident X-ray and H-alpha emission about 11.6 kpc to the north of the galaxy M82 previously discussed by Devine and Bally (1999). The PSPC X-ray spectrum is fit by thermal plasma (kT=0.80+-0.17 keV) absorbed by only the Galactic foreground column density. We evaluate the relationship of the X-ray/H-alpha ridge to the M82 superwind. The main properties of the X-ray emission can all be explained as being due to shock-heating driven as the superwind encounters a massive ionized cloud in the halo of M82. This encounter drives a slow shock into the cloud, which contributes to the excitation of the observed H-alpha emission. At the same time, a fast bow-shock develops in the superwind just upstream of the cloud, and this produces the observed X-ray emission. This interpretation would imply that the superwind has an outflow speed of roughly 800 km/s, consistent with indirect estimates based on its general X-ray properties and the kinematics of the inner kpc-scale region of H-alpha filaments. The gas in the M82 ridge is roughly two orders-of-magnitude hotter than the minimum "escape temperature" at this radius, so this gas will not be retained by M82. (abridged)Comment: 24 pages (latex), 3 figures (2 gif files and one postscript), accepted for publication in Part 1 of The Astrophysical Journa

ASCA Observations of the Starburst-Driven Superwind Galaxy NGC 2146: Broad Band (0.6 - 9 keV) Spectral Properties

We report ASCA GIS and SIS observations of the nearby (D = 11.6 Mpc), nearly edge-on, starburst galaxy NGC 2146. These X-ray spectral data complement ROSAT PSPC and HRI imaging discussed by Armus et al., 1995. The broad band (0.6-9 keV) X-ray spectrum of NGC 2146 is best described by a two component model: the soft X-ray emission with a Raymond-Smith thermal plasma model having a temperature of kT $\sim 0.8$ keV; the hard X-ray emission with a thermal plasma model having kT $\sim 8$ keV or a power-law model having a photon index of $\sim 1.7$. We do not find compelling evidence of substantial excess absorption above the Galactic value. The soft (hard) thermal component provides about 30% (70%) of the total luminosity in the 0.5 - 2.0 keV energy band, while in the 2-10 keV energy range only the hard component plays a major role. The spectral results allow us to set tighter constraints on the starburst-driven superwind model, which we show can satisfactorily account for the luminosity, mass, and energy content represented by the soft X-ray spectral component. We estimate that the mass outflow rate ($\sim$ 9 M$_{\odot}$ per year) is about an order of magnitude greater than the predicted rate at which supernovae and stellar winds return mass into the interstellar medium and, therefore, argue that the flow is strongly "mass-loaded" with material in and around the starburst. The estimated outflow velocity of the hot gas is close to the escape velocity from the galaxy, so the fate of the gas is not clear. We suggest that the hard X-ray spectral component is due to the combined emission of X-ray binaries and/or young supernovae remnants associated with the starburst.Comment: 26 pages plus 4 figures, LaTex manuscript, Accepted for publication in the Astrophysical Journa

Success Rate of Embolization for Type II Endoleaks at a Major Tertiary Referral Center

Objective: The rise of endovascular aneurysm repair (EVAR) as the preferred treatment for abdominal aortic aneurysm (AAA) has introduced endoleaks as a major complication following AAA repair. The objective of this study is to assess the outcomes associated with endovascular embolization of type II endoleaks after EVAR. Methods: The institutional Radiology database at our tertiary referral hospital was queried for type II endoleak during the period 2006-2018. A retrospective chart review was then carried out. Only patients who underwent intervention for isolated type 2 endoleaks were analyzed. The primary outcome was success of the endoleak repair as determined by cessation of growth (i.e., ≤5mm change in diameter over follow-up period) of the native aneurysm sac. Patient outcomes for each failure of the above criterion were also collected. Other data pertaining to the location of endoleak, type of occlusion performed, type of embolic agent used, type of endograft used for EVAR, and incidence of aneurysm rupture were collected as secondary outcomes.Results:During this period 41 patients were treated for type II endoleaks. Demographics are shown in table 1. Cessation of growth was achieved in 28/41 (68.3%) of the patients after one embolization procedure. In 13/41 (31.7%) of patients, growth of the native aneurysm sac continued. Of the patients whose aneurysms continued to grow, 61.5% (8/13) did not undergo a second embolization. The remaining 38.5% (5/13) underwent a second embolization.Patient outcomes for both of these groups are presented in table II. None of the patients were found to have ruptured their aneurysm sac during follow-up after embolization. None of gender, race, the embolization site, or method of embolization were associated with embolization failure. Conclusions: Embolization of type II endoleaks is associated with a cessation of growth in the majority of cases and seems to be protective regarding the risk of aneurysm sac rupture. Future studies and additional follow-up will be important to elucidate the most significant risk factors for expansion and/or rupture of the endovascularly repaired abdominal aneurysm.Table I: Demographics for patients with type II endoleaks who underwent endovascular embolizationVariableValue Age (years +/- sd)75.66 +/- yearsAverage follow-up (months)62.65 monthsSex (%)71.7% male28.3% femaleRace (%)77.7% white17.8% black4.4% otherInflow vessel (%)43.2% lumbar only36.4% IMA only20.5% mixEmbolization site (%)40.5% vessel only14.3% cavity only20.5% mixEmbolization type (%)66.7% coil9.5% glue23.8% mixTable II: Outcomes for patients with continued growth after embolizationThose that did no undergo further embolizationThose that underwent a second embolization 3 were found to have type III endoleak and were successfully repaired with lining of the graft.2 whose aneurysm sac ceased growing. 2 who declined further treatment. 2 whose aneurysm sac continued to grow with persistent evidence of endoleak.1 who died from non-vascular complications. 1 who was lost to follow-up. 1 who is scheduled future surgical repair. 1 who was lost to follow-up.https://scholarlycommons.henryford.com/merf2019clinres/1026/thumbnail.jp

Transfer of Information from Personal Health Records: A Survey of Veterans Using My HealtheVet

Abstract Objective: Personal health records provide patients with ownership of their health information and allow them to share information with multiple healthcare providers. However, the usefulness of these records relies on patients understanding and using their records appropriately. My HealtheVet is a Web-based patient portal containing a personal health record administered by the Veterans Health Administration. The goal of this study was to explore veterans' interest and use of My HealtheVet to transfer and share information as well as to identify opportunities to increase veteran use of the My HealtheVet functions. Materials and Methods: Two waves of data were collected in 2010 through an American Customer Satisfaction Index Web-based survey. A random sample of veterans using My HealtheVet was invited to participate in the survey conducted on the My HealtheVet portal through a Web-based pop-up browser window. Results: Wave One results (n=25,898) found that 41% of veterans reported printing information, 21% reported saving information electronically, and only 4% ever sent information from My HealtheVet to another person. In Wave Two (n=18,471), 30% reported self-entering medication information, with 18% sharing this information with their Veterans Affairs (VA) provider and 9.6% sharing with their non-VA provider. Conclusion: Although veterans are transferring important medical information from their personal health records, increased education and awareness are needed to increase use. Personal health records have the potential to improve continuity of care. However, more research is needed on both the barriers to adoption as well as the actual impact on patient health outcomes and well-being.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98490/1/tmj%2E2011%2E0109.pd

Augmented Method to Improve Thermal Data for the Figure Drift Thermal Distortion Predictions of the JWST OTIS Cryogenic Vacuum Test

The JWST Optical Telescope Element (OTE) assembly is the largest optically stable infrared-optimized telescope currently being manufactured and assembled, and is scheduled for launch in 2018. The JWST OTE, including the 18 segment primary mirror, secondary mirror, and the Aft Optics Subsystem (AOS) are designed to be passively cooled and operate near 45K. These optical elements are supported by a complex composite backplane structure. As a part of the structural distortion model validation efforts, a series of tests are planned during the cryogenic vacuum test of the fully integrated flight hardware at NASA JSC Chamber A. The successful ends to the thermal-distortion phases are heavily dependent on the accurate temperature knowledge of the OTE structural members. However, the current temperature sensor allocations during the cryo-vac test may not have sufficient fidelity to provide accurate knowledge of the temperature distributions within the composite structure. A method based on an inverse distance relationship among the sensors and thermal model nodes was developed to improve the thermal data provided for the nanometer scale WaveFront Error (WFE) predictions. The Linear Distance Weighted Interpolation (LDWI) method was developed to augment the thermal model predictions based on the sparse sensor information. This paper will encompass the development of the LDWI method using the test data from the earlier pathfinder cryo-vac tests, and the results of the notional and as tested WFE predictions from the structural finite element model cases to characterize the accuracies of this LDWI method