2,356 research outputs found
Test of sodium boiling in a single tube-in- shell heat exchanger over the range 1720 deg to 1980 deg F /1211 to 1355 K/
Bimetallic heat exchanger tube performance in sodium boiling facilit
Invaluable Involvement: Purposive Interest Group Networks in the 21st Century
We present the first social network analysis of purposive and coordinated interest group relationships. We utilize a network measure based on cosigner status to United States Supreme Court amicus curiae, or friend of the court briefs. The illuminated structures lend insight into the central players and overall formation of the network over the first seven years of the 21st century. We find that the majority of interest groups primarily partake in coalition strategies with other groups of similar policy interest and ideological character. This is in contrast to previous literature that focused only on one or the other. The factions are tied together by various central players, who act as hubs, leaving a disparate collection of organizations that work alone. Network analysis provides evidence, for example, that the National Wildlife Foundation, the National Association of Criminal Defense Lawyers and the American Civil Liberties Union are all particularly strong groups, but exploit different central roles. Ultimately, our work and data suggest several subsequent questions and opportunities pertaining to the coalition strategies of interest groups
The Factors of Interest Group Networks and Success: Organization, Issues and Resources
While interest groups use a variety of techniques to exert influence, coalition strategies are the dominant lobbying technique. However, many questions remain about such coalitions. This paper is the second in a series of social network analyses of purposive and coordinated interest group relationships. We utilize a network measure based on cosigner status to United States Supreme Court amicus curiae, or friend of the court briefs. The illuminated structures lend insight into the central players and overall formation of the network over the first several years of the 21st century. The factions are tied together by various central players, who act as hubs, leaving a disparate collection of organizations that work alone. Using an exponential-family random graph model (ERGM), we find that graph-theorectic and organizational characteristics, such as size and budget, as well as policy interests explain interest group network formation
Quenching of lamellar ordering in an n-alkane embedded in nanopores
We present an X-ray diffraction study of the normale alkane nonadecane
C_{19}H_{40} embedded in nanoporous Vycor glass. The confined molecular crystal
accomplishes a close-packed structure by alignment of the rod-like molecules
parallel to the pore axis while sacrificing one basic principle known from the
bulk state, i.e. the lamellar ordering of the molecules. Despite this disorder,
the phase transitions observed in the confined solid mimic the phase behavior
of the 3D unconfined crystal, though enriched by the appearance of a true
rotator phase known only from longer alkane chains.Comment: 7 pages, 3 figure
A strong web presence can equalize the playing field for long shot candidates in Presidential party nominations
While few would doubt that the Internet is now an important component in any election, especially the presidential, what effects does a candidatesâ web presence have on their electoral chances, and is this something that they are able to influence? Using data from the 2008 presidential nominations, Dino P. Christenson, Corwin D. Smidt and Costas Panagopoulos investigate how candidateâs web presence differs from traditional indicators of campaign performance and if it can help them to gain greater financial and electoral support. They find that campaign frontrunners have a limited ability to control their web presence, but that outsider candidates can have more success. They also show that candidates with a greater web presence see greater successes in fundraising
Limiting current in a crossedâfield gap
An analytic theory is presented that yields the maximum transmittable current across an anodeâcathode gap that is embedded in an arbitrary transverse magnetic field (B). The limiting current is found to be relatively insensitive to B for all B<BH, where BH is the Hull cutoff magnetic field required for magnetic insulation. The classical ChildâLangmuir solution is recovered in the limit Bâ0.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71084/2/PFBPEI-5-12-4486-1.pd
Resistive destabilization of cycloidal electron flow and universality of (nearâ) Brillouin flow in a crossedâfield gap
It is shown that a small amount of dissipation, caused by current flow in a lossy external circuit, can produce a disruption of steadyâstate cycloidal electron flow in a crossedâfield gap, leading to the establishment of a turbulent steady state that is close to, but not exactly, Brillouin flow. This disruption, which has nothing to do with a diocotron or cyclotron instability, is fundamentally caused by the failure of a subset of the emitted electrons to return to the cathode surface as a result of resistive dissipation. This mechanism was revealed in particle simulations, and was confirmed by an analytic theory. These nearâBrillouin states differ in several interesting respects from classic Brillouin flow, the most important of which is the presence of a microsheath and a timeâvarying potential minimum very close to the cathode surface. They are essentially identical to that produced when (i) injected current exceeds a certain critical value [P. J. Christenson and Y. Y. Lau, Phys. Plasmas 1, 3725 (1994)] or (ii) a small rf electric field is applied to the gap [P. J. Christenson and Y. Y. Lau, Phys. Rev. Lett. 76, 3324 (1996)]. It is speculated that such nearâBrillouin states are generic in vacuum crossedâfield devices, due to the ease with which the cycloidal equilibrium can be disrupted. Another novel aspect of this paper is the introduction of transformations by which the nonlinear, coupled partial differential equations in the Eulerian description (equation of motion, continuity equation, Poisson equation, and the circuit equation) are reduced to an equivalent system of very simple linear ordinary differential equations. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71350/2/PHPAEN-3-12-4455-1.pd
Atrial fibrillation impairs the diagnostic performance of cardiac natriuretic peptides in dyspneic patients. results from the BACH Study (Biomarkers in ACute Heart Failure)
Objectives: The purpose of this study was to assess the impact of atrial fibrillation (AF) on the performance of mid-region amino terminal pro-atrial natriuretic peptide (MR-proANP) in comparison with the B-type peptides (BNP and NT-proBNP) for diagnosis of acute heart failure (HF) in dyspneic patients. Background: The effects of AF on the diagnostic and prognostic performance of MR-proANP in comparison with the B type natriuretic peptides have not been previously reported. Methods: A total of 1,445 patients attending the emergency department with acute dyspnea had measurements taken of MR-proANP, BNP, and NT-proBNP values on enrollment to the BACH trial and were grouped according to presence or absence of AF and HF. Results: AF was present in 242 patients. Plasma concentrations of all three peptides were lowest in those with neither AF nor HF and AF without HF was associated with markedly increased levels (p < 0.00001). HF with or without AF was associated with a significant further increment (p < 0.00001 for all three markers). Areas under receiver operator characteristic curves (AUCs) for discrimination of acute HF were similar and powerful for all peptides without AF (0.893 to 0.912; all p < 0.001) with substantial and similar reductions (0.701 to 0.757) in the presence of AF. All 3 peptides were independently prognostic but there was no interaction between any peptide and AF for prediction of all-cause mortality. Conclusions: AF is associated with increased plasma natriuretic peptide (MR-proANP, BNP and NT-proBNP) levels in the absence of HF. The diagnostic performance of all three peptides is impaired by AF. This warrants consideration of adjusted peptide thresholds for diagnostic use in AF and mandates the continued search for markers free of confounding by AF
- âŠ