5,503 research outputs found

    The Earned Income Tax Credit: Antipoverty Effectiveness and Labor Market Effects

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    The authors begin with a detailed assessment then perform empirical analyses to predict the outcomes of changes to the structure of the program.https://research.upjohn.org/up_press/1099/thumbnail.jp

    Then and Now: The Earned Income Tax Credit

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    Nonadherence to primary prophylaxis against Pneumocystis jirovecii pneumonia.

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    BackgroundDespite the effectiveness of prophylaxis, Pneumocystis jirovecii pneumonia (PCP) continues to be the most common serious opportunistic infection among HIV-infected persons. We describe factors associated with nonadherence to primary PCP prophylaxis.Methodology/principal findingsWe used 2000-2004 data from the Supplement to HIV/AIDS Surveillance (SHAS) project, a cross-sectional interview project of HIV-infected persons >or=18 years conducted in 18 states. We limited the analysis to persons who denied having prior PCP, reported having a current prescription to prevent PCP, and answered the question "In the past 30 days, how often were you able to take the PCP medication(s) exactly the way your doctor told you to take them?" We used multivariable logistic regression to describe factors associated with nonadherence. Of 1,666 subjects prescribed PCP prophylaxis, 305 (18.3%) were nonadherent. Persons were more likely to be nonadherent if they reported using marijuana (adjusted odds ratio [aOR] = 1.6, 95% confidence interval [CI] = 1.1-2.4), non-injection drugs other than marijuana (aOR = 1.5, 95% CI = 1.0-2.1), or injection drugs (aOR = 2.3, 95% CI = 1.3-4.1) in the past year; their mental health was "not good" for >or=1 day during the past month (aOR = 1.6, 95% CI = 1.2-2.2); their most recent CD4 count was <200 cells/microL (aOR = 1.6, 95% CI = 1.1-2.2); or taking ART usually (aOR = 9.6, 95% CI = 6.7-13.7) or sometimes/rarely/never (aOR = 18.4, 95% CI = 11.1-30.4), compared with always, as prescribed.Conclusion/significanceProviders should inquire about and promote strategies to improve adherence to PCP prophylaxis, particularly among persons who use illicit drugs, have mental health issues, and who are not compliant with ART to reduce the occurrence of PCP

    Second moment closure analysis of the backstep flow database

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    A Second Moment Closure computation (SMC) is compared in detail with the Direct Numerical Simulation (DNS) data of Le and Moin for the backstep flow at Re = 5,000 in an attempt to understand why the intensity of the backflow and, consequently, the friction coefficient in the recirculation bubble are severely underestimated. The data show that this recirculation bubble is far from being laminar except in the very near wall layer. A novel 'differential a priori' procedure was used, in which the full transport equation for one isolated component of the Reynolds stress tensor was solved using DNS data as input. Conclusions are then different from what would have been deduced by comparing a full simulation to a DNS. One cause of discrepancy was traced back to insufficient transfer of energy to the normal stress by pressure strain, but was not cured. A significant finding, confirmed by the DNS data in the core region of a channel flow, is that the coefficient that controls destruction of dissipation, C epsilon(sub 2), should be decreased by a factor of 2 when production is vanishing. This is also the case in the recirculation bubble, and a new formulation has cured 25% of the backflow discrepancy

    Static internal performance of a nonaxisymmetric vaned thrust reverser with flow splay capability

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    An investigation was conducted in the Static Test Facility of the Langley 16-Foot Transonic Tunnel on a dual-port, nonaxisymmetric, block-and-turn type thrust reverser model with vane cascades in the reverser ports which turned the flow in the splay direction and aided in turning the flow in the reverse direction. Splaying reverser flow is a method of delaying to lower landing ground roll speeds the reingestion of hot exhaust flow into the inlets. Exhaust flow splay can also help prevent the impingement of hot exhaust gases on the empennage surfaces when the reverser is integrated into an actual airframe. The vane cascades consisted of two sets of perpendicular vanes with a variable number of turning and splay vanes. A skewed vane box was also tested which had only one set of vanes angled to provide both turning and splay. Vane cascades were designed to provide different amounts of flow splay in the top and bottom ports. Inner doors, trim tabs, and an orifice plate all provided means of varying the port area for reverser flow modulation. The outer door position was varied as a means of influencing the flow reverse angle. Nozzle pressure ratio was varied from 1.75 to approximately 6.00

    Biomacromolecular stereostructure mediates mode hybridization in chiral plasmonic nanostructures

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    The refractive index sensitivity of plasmonic fields has been exploited for over 20 years in analytical technologies. While this sensitivity can be used to achieve attomole detection levels, they are in essence binary measurements that sense the presence/absence of a predetermined analyte. Using plasmonic fields, not to sense effective refractive indices but to provide more “granular” information about the structural characteristics of a medium, provides a more information rich output, which affords opportunities to create new powerful and flexible sensing technologies not limited by the need to synthesize chemical recognition elements. Here we report a new plasmonic phenomenon that is sensitive to the biomacromolecular structure without relying on measuring effective refractive indices. Chiral biomaterials mediate the hybridization of electric and magnetic modes of a chiral solid-inverse plasmonic structure, resulting in a measurable change in both reflectivity and chiroptical properties. The phenomenon originates from the electric-dipole–magnetic-dipole response of the biomaterial and is hence sensitive to biomacromolecular secondary structure providing unique fingerprints of α-helical, β-sheet, and disordered motifs. The phenomenon can be observed for subchiral plasmonic fields (i.e., fields with a lower chiral asymmetry than circularly polarized light) hence lifting constraints to engineer structures that produce fields with enhanced chirality, thus providing greater flexibility in nanostructure design. To demonstrate the efficacy of the phenomenon, we have detected and characterized picogram quantities of simple model helical biopolymers and more complex real proteins

    The Unitary Executive during the Third Half-Century, 1889-1945

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    Recent Supreme Court decisions and the impeachment of President Clinton has reinvigorated the debate over Congress\u27s authority to employ devices such as special counsels and independent agencies to restrict the President\u27s control over the administration of the law. The initial debate focused on whether the Constitution rejected the executive by committee employed by the Articles of the Confederation in favor of a unitary executive, in which all administrative authority is centralized in the President. More recently, the debate has begun to turn towards historical practices. Some scholars have suggested that independent agencies and special counsels have become such established features of the constitutional landscape as to preempt arguments in favor of the unitary executive. Others, led by Bruce Ackerman, have suggested that the New Deal represented a constitutional moment that ratified major changes in the distribution of power within the federal government. To date, however, a complete assessment of the historical record has yet to appear. This Article is part of a larger project that offers a comprehensive chronicle that places the battles between the President and Congress over control of the administration of federal law in historical perspective. It reviews the period between 1889 and 1945, beginning with the Administration of Benjamin Harrison, ending with the Administration of Franklin Delano Roosevelt, and paying particular attention to FDR\u27s failed attempt to reorganized the executive branch. The record reveals that these Presidents during this period consistently defended the unitariness of the executive branch to a degree sufficient to keep the issue from being foreclosed by history. In fact, the episodes discussed provide eloquent illustrations of the legal and normative arguments supporting the unitary executive

    Teaching computer science with robotics using Ada/Mindstorms 2.0

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