510 research outputs found
Investigation of methods to produce a uniform cloud of fuel particles in a flame tube
The combustion of a uniform, quiescent cloud of 30-micron fuel particles in a flame tube was proposed as a space-based, low-gravity experiment. The subject is the normal- and low-gravity testing of several methods to produce such a cloud, including telescoping propeller fans, air pumps, axial and quadrature acoustical speakers, and combinations of these devices. When operated in steady state, none of the methods produced an acceptably uniform cloud (+ or - 5 percent of the mean concentration), and voids in the cloud were clearly visible. In some cases, severe particle agglomeration was observed; however, these clusters could be broken apart by a short acoustic burst from an axially in-line speaker. Analyses and experiments reported elsewhere suggest that transient, acoustic mixing methods can enhance cloud uniformity while minimizing particle agglomeration
Shifting patterns of genomic variation in the somatic evolution of papillary thyroid carcinoma
Shows Single Nucleotide Substitutions in the MAPK Pathway. (XLSX 43 kb
In and Out of Equilibrium II: Evolution in Repeated Games with Discounting and Complexity Costs
Previous tuberculosis disease as a risk factor for chronic obstructive pulmonary disease:a cross-sectional analysis of multicountry, population-based studies
Background Risk factors for COPD in high-income settings are well understood; however, less attention has been paid to contributors of COPD in low-income and middle-income countries (LMICs) such as pulmonary tuberculosis. We sought to study the association between previous tuberculosis disease and COPD by using pooled population-based cross-sectional data in 13 geographically diverse, low-resource settings. Methods We pooled six cohorts in 13 different LMIC settings, 6 countries and 3 continents to study the relationship between self-reported previous tuberculosis disease and lung function outcomes including COPD (defined as a postbronchodilator forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) below the lower limit of normal). Multivariable regressions with random effects were used to examine the association between previous tuberculosis disease and lung function outcomes. Results We analysed data for 12 396 participants (median age 54.0 years, 51.5% male); 332 (2.7%) of the participants had previous tuberculosis disease. Overall prevalence of COPD was 8.8% (range 1.7%-15.5% across sites). COPD was four times more common among those with previous tuberculosis disease (25.7% vs 8.3% without previous tuberculosis disease,
No Exit? Withdrawal Rights and the Law of Corporate Reorganizations
Bankruptcy scholarship is largely a debate about the comparative merits of a mandatory regime on one hand and bankruptcy by free design on the other. By the standard account, the current law of corporate reorganization is mandatory. Various rules that cannot be avoided ensure that investors’ actions are limited and they do not exercise their rights against specialized assets in a way that destroys the value of a business as a whole. These rules solve collective action problems and reduce the risk of bargaining failure. But there are costs to a mandatory regime. In particular, investors cannot design their rights to achieve optimal monitoring as they could in a system of bankruptcy by free design. This Article suggests that the academic debate has missed a fundamental feature of the law. Bankruptcy operates on legal entities, not on firms in the economic sense. For this reason, sophisticated investors do not face a mandatory regime at all. The ability of investors to place assets in separate entities gives them the ability to create specific withdrawal rights in the event the firm encounters financial distress. There is nothing mandatory about rules like the automatic stay when assets can be partitioned off into legal entities that are beyond the reach of the bankruptcy judge. Thus, by partitioning assets of one economic enterprise into different legal entities, investors can create a tailored bankruptcy regime. In this way, legal entities serve as building blocks that can be combined to create specific and varied but transparent investor withdrawal rights. This regime of tailored bankruptcy has been unrecognized and underappreciated and may be preferable to both mandatory and free design regimes. By allowing a limited number of investors to opt out of bankruptcy in a particular, discrete, and visible way, investors as a group may be able to both limit the risk of bargaining failure and at the same time enjoy the disciplining effect that a withdrawal right brings with it
Long-Horizon Consumption Risk and the Cross-Section of Returns: New Tests and International Evidence
Grafted polymer chains suppress nanoparticle diffusion in athermal polymer melts
We measure the center-of-mass diffusion of poly(methyl methacrylate) (PMMA)-grafted nanoparticles
(NPs) in unentangled to slightly entangled PMMA melts using Rutherford backscattering
spectrometry. These grafted NPs diffuse ∼100 times slower than predicted by the Stokes-Einstein
relation assuming a viscosity equal to bulk PMMA and a hydrodynamic NP size equal to the NP core
diameter, 2Rcore = 4.3 nm. This slow NP diffusion is consistent with an increased effective NP size,
2Reff ≈ 20 nm, nominally independent of the range of grafting density and matrix molecular weights
explored in this study. Comparing these experimental results to a modified Daoud-Cotton scaling
estimate for the brush thickness as well as dynamic mean field simulations of polymer-grafted NPs in
athermal polymer melts, we find that 2Reff is in quantitative agreement with the size of the NP core plus
the extended grafted chains. Our results suggest that grafted polymer chains of moderate molecular
weight and grafting density may alter the NP diffusion mechanism in polymer melts, primarily by
increasing the NP effective size
CTSA Consortium Consensus Scientific Review Committee (SRC) Working Group Report on the SRC Processes
Human research projects must have a scientifically valid study design, analytic plan, and be operationally feasible in order to be successfully completed and thus to have translational impact. To ensure this, institutions that conduct clinical research should have a scientific review process prior to submission to the Institutional Review Committee (IRB). This paper reports the Clinical and Translational Science Award (CTSA) Consortium Scientific Review Committee (SRC) Consensus Working Group's proposed framework for a SRC process. Recommendations are provided for institutional support and roles of CTSAs, multisite research, criteria for selection of protocols that should be reviewed, roles of committee members, application process, and committee process. Additionally, to support the SCR process effectively, and to ensure efficiency, the Working Group recommends information technology infrastructures and evaluation metrics to determine outcomes are provided
Are Collateral Sanctions Premised on Conduct or Conviction? The Case of Abortion Doctors
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