21,398 research outputs found
Miniature modular microwave end-to-end receiver
An end-to-end microwave receiver system contained in a single miniature hybrid package mounted on a single heatsink is presented. It includes an input end connected to a microwave receiver antenna and an output end which produces a digital count proportional to the amplitude of a signal of a selected microwave frequency band received at the antenna and corresponding to one of the water vapor absorption lines near frequencies of 20 GHz or 30 GHz. The hybrid package is on the order of several centimeters in length and a few centimeters in height and width. The package includes an L-shaped carrier having a base surface, a vertical wall extending up from the base surface and forming a corner therewith, and connection pins extending through the vertical wall. Modular blocks rest on the base surface against the vertical wall and support microwave monolithic integrated circuits on top surfaces thereof connected to the external connection pins. The modular blocks lie end-to-end on the base surface so as to be modularly removable by sliding along the base surface beneath the external connection pins away from the vertical wall
Cost of health care utilization among homeless frequent emergency department users
Research demonstrates that homelessness is associated with frequent use of emergency department (ED) services, yet prior studies have not adequately examined the relationship between frequent ED use and utilization of non-ED health care services among those experiencing homelessness. There has also been little effort to assess heterogeneity among homeless individuals who make frequent use of ED services. To address these gaps, the present study used Medicaid claims data from 2010 to estimate the association between the number of ED visits and non-ED health care costs for a cohort of 6,338 Boston Health Care for the Homeless Program patients, and to identify distinct subgroups of persons in this cohort who made frequent use of ED services based on their clinical and demographic characteristics. A series of gamma regression models found more frequent ED use to be associated with higher non-ED costs, even after adjusting for demographic and clinical characteristics. Latent class analysis was used to examine heterogeneity among frequent ED users, and the results identified 6 characteristically distinct subgroups among these persons. The subgroup of persons with trimorbid illness had non-ED costs that far exceeded members of all 5 other subgroups. Study findings reinforce the connection between frequent ED use and high health care costs among homeless individuals and suggest that different groups of homeless frequent ED users may benefit from interventions that vary in terms of their composition and intensity
Fibulin-4 is essential for maintaining arterial wall integrity in conduit but not muscular arteries
Homozygous or compound heterozygous mutations in fibulin-4 (FBLN4) lead to autosomal recessive cutis laxa type 1B (ARCL1B), a multisystem disorder characterized by significant cardiovascular abnormalities, including abnormal elastin assembly, arterial tortuosity, and aortic aneurysms. We sought to determine the consequences of a human disease-causing mutation in FBLN4 (E57K) on the cardiovascular system and vascular elastic fibers in a mouse model of ARCL1B. Fbln4E57K/E57K mice were hypertensive and developed arterial elongation, tortuosity, and ascending aortic aneurysms. Smooth muscle cell organization within the arterial wall of large conducting vessels was abnormal, and elastic fibers were fragmented and had a moth-eaten appearance. In contrast, vessel wall structure and elastic fiber integrity were normal in resistance/muscular arteries (renal, mesenteric, and saphenous). Elastin cross-linking and total elastin content were unchanged in large or small arteries, whereas elastic fiber architecture was abnormal in large vessels. While the E57K mutation did not affect Fbln4 mRNA levels, FBLN4 protein was lower in the ascending aorta of mutant animals compared to wild-type arteries but equivalent in mesenteric arteries. We found a differential role of FBLN4 in elastic fiber assembly, where it functions mainly in large conduit arteries. These results suggest that elastin assembly has different requirements depending on vessel type. Normal levels of elastin cross-links in mutant tissue call into question FBLN4\u27s suggested role in mediating lysyl oxidase-elastin interactions. Future studies investigating tissuespecific elastic fiber assembly may lead to novel therapeutic interventions for ARCL1B and other disorders of elastic fiber assembly. 2017 © The Authors, some rights reserved
The 8 o'clock Arc: A Serendipitous Discovery of a Strongly Lensed Lyman Break Galaxy in the SDSS DR4 Imaging Data
We report on the serendipitous discovery of the brightest Lyman Break Galaxy
(LBG) currently known, a galaxy at z=2.73 that is being strongly lensed by the
z=0.38 Luminous Red Galaxy (LRG) SDSS J002240.91+143110.4. The arc of this
gravitational lens system, which we have dubbed the "8 o'clock arc" due to its
time of discovery, was initially identified in the imaging data of the Sloan
Digital Sky Survey Data Release 4 (SDSS DR4); followup observations on the
Astrophysical Research Consortium (ARC) 3.5m telescope at Apache Point
Observatory confirmed the lensing nature of this system and led to the
identification of the arc's spectrum as that of an LBG. The arc has a spectrum
and a redshift remarkably similar to those of the previous record-holder for
brightest LBG (MS 1512-cB58, a.k.a "cB58"), but, with an estimated total
magnitude of (g,r,i) = (20.0,19.2,19.0) and surface brightness of
(mu_g,mu_r,mu_i) = (23.3, 22.5, 22.3) mag/arcsec^2, the 8 o'clock arc is thrice
as bright. The 8 o'clock arc, which consists of three lensed images of the LBG,
is 162deg (9.6arcsec) long and has a length-to-width ratio of 6:1. A fourth
image of the LBG -- a counter-image -- can also be identified in the ARC 3.5m
g-band images. A simple lens model for the system assuming a singular
isothermal ellipsoid potential yields an Einstein radius of 2.91+/-0.14 arcsec,
a total mass for the lensing LRG (within the (10.6+/-0.5)/h kpc enclosed by the
lensed images) of 1.04x10^12/h Msun, and a magnification factor for the LBG of
12.3(+15/-3.6). The LBG itself is intrinsically quite luminous (approximately
6L*) and shows indications of massive recent star formation, perhaps as high as
160/h Msun/year.Comment: 4 pages 5 figures, submitted to ApJ Letter
Do Differences in Pleadings Standards Cause Forum Shopping in Securities Class Actions?: Doctrinal and Empirical Analyses
Federal appellate courts have promulgated divergent legal standards for pleading fraud in securities fraud class actions after the Private Securities Litigation Reform Act (PSLRA). Recently, the Supreme Court of the United States issued a decision in Tellabs, Inc. v. Makor Issues & Rights, Ltd. that could have resolved these differences, but did not do so. This Paper provides two significant contributions. We first show that Tellabs avoids deciding the hard issues that confront courts and litigants daily in the wake of the PSLRA\u27s heightened pleading standard. As a consequence, the opinion keeps very much alive the circuits\u27 disparate interpretations of the PSLRA\u27s fraud pleading standard. To be sure, Tellabs might ultimately be applied by lower courts to narrow the range of permissible approaches to satisfying the strong inference standard, but leaves a good deal of room within which wide variations in approach will continue. Our second contribution is empirical in that we seek to answer the question: do plaintiffs\u27 attorneys take advantage of the differences among the circuits\u27 interpretation of the pleading standard to select more favorable venues to file their cases, as some scholars have claimed? We find that 85 percent of the securities fraud class actions in our sample are filed in the home circuit of the defendant corporation. While we find that the differences in the circuits\u27 pleading standards do not have a statistically significant impact on the plaintiffs\u27 choice of venue, we find that plaintiffs are more likely to file low-value cases in jurisdictions other than the one in which the defendant\u27s headquarters is located
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PND54 Long-Term Costs and Consequences of Patients with Familial Chylomicronemia Syndrome – A Simulation Model Approach
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