Experiments with an Airfoil Model on which the Boundary Layers are Controlled Without the Use of Supplementary Equipment

This report describes test made in the Variable Density Wind Tunnel of the NACA to determine the possibility of controlling the boundary layer on the upper surface of an airfoil by use of the low pressure existing near the leading edge. The low pressure was used to induce flow through slots in the upper surface of the wing. The tests showed that the angle of attack for maximum lift was increased at the expense of a reduction in the maximum lift coefficient and an increase in the drag coefficient

The Doha Round’s Public Health Legacy: Strategies for the Production and Diffusion of Patented Medicines Under the Amended TRIPS Provisions

This entry into force of the World Trade Organization (WTO) TRIPS Agreement in 1995 transformed the international intellectual property system. The harmonization of basic intellectual property standards has operated to protect investment in innovation, limiting risks from unjustified \u27free riding.\u27 Yet these same harmonized IP standards sharply curtailed the traditional capacity of suppliers of public goods, such as health care and nutrition, to address the priority needs of less affluent members of society, particularly in (but not limited to) developing countries. In the Doha Declaration, the Waiver Decision of 30 August 2003 and the Article 31bis Protocol of Amendment, stakeholders concerned with re-opening policy space for the supply of newer pharmaceutical products pushed back against the restrictive elements of the TRIPS Agreement. Governments around the world are in the process of deciding whether to ratify and accept the Article 31bis Amendment. Based on their Study for the International Trade Committee of the European Parliament, the authors argue that acceptance of the Amendment will provide a \u27net benefit\u27 for countries seeking to improve access to medicines. At the insistence of WTO delegations acting on behalf of the originator pharmaceutical industry lobby, Article 31bis regrettably is saddled with unnecessary administrative hurdles. Nonetheless, through skillful lawyering, political determination and coordinated planning, the system can be made to work. Among other options, expeditious back-to-back compulsory licensing linked with pooled procurement strategies may effectively achieve economies of scale in production and distribution of medicines. The authors doubt that the international political environment would support renegotiation of an \u27improved\u27 solution. They express concern that failure to bring the Amendment into force will open the door to a campaign to undermine the Waiver Decision. Recent events in Brazil and Thailand illustrate both the opportunities and risks associated with implementing TRIPS exception mechanisms, and help to inform views on the negotiating environment. Specific proposals for regional cooperation in implementing the Amendment are laid out, and the authors emphasize the importance of pursuing concrete transfer of technology measures in support of developing country pharmaceutical manufacturing. Over-reliance on private market mechanisms for the supply of public health goods leaves the international community with an unresolved collective action problem on a large scale

Attachment methods for advanced spacecraft thermal control materials - An annotated bibliography, phase 1 Summary report supplement

Annotated bibliography on attachment methods for advanced spacecraft thermal control material

Experiments with a Model Water Tunnel

This report describes a model water tunnel built in 1928 by the NACA to investigate the possibility of using water tunnels for aerodynamic investigations at large scales. The model tunnel is similar to an open-throat wind tunnel, but uses water for the working fluid

THE VALUE OF WATER AS AN URBAN CLUB GOOD: A MATCHING APPROACH TO HOA-PROVIDED LAKES

Urban lakes located in arid environments require large quantities of water to maintain their water levels, with much of this water associated with high opportunity costs. Many of these lakes are manmade and provide various amenities to surrounding residents. In this paper we use matching techniques to recover the average capitalized value of lakes to surrounding communities and differentiate between community members and adjacent households to recover heterogeneous treatment effects. Importantly, we consider the role of both unobservable and observable features of matching to recover heterogeneous capitalization across lake communities. Our results suggest that the capitalized value of lakes to community residents is highly heterogeneous and ranges from an annual value of -$29 to +$20 per homeowner per acre foot of water. These results suggest that small changes in water pricing could remove the surplus benefits of lakes to community residents.Matching, Treatment effects, Urban lakes, Capitalization, Environmental Economics and Policy, Political Economy, Resource /Energy Economics and Policy,

Traditional versus rule-based programming techniques: Application to the control of optional flight information

To the software design community, the concern over the costs associated with a program's execution time and implementation is great. It is always desirable, and sometimes imperative, that the proper programming technique is chosen which minimizes all costs for a given application or type of application. A study is described that compared cost-related factors associated with traditional programming techniques to rule-based programming techniques for a specific application. The results of this study favored the traditional approach regarding execution efficiency, but favored the rule-based approach regarding programmer productivity (implementation ease). Although this study examined a specific application, the results should be widely applicable

Avian embryonic development in hyperdynamic environments

Embryos which developed for 24 hours in the oviduct of hens maintained at 2 G and which were subsequently incubated at Earth gravity had a 14% reduction in hatchability. Increased mortality during the first 4 days, and an increase in embryonic abnormalities were of the types usually found during the first mortality peak (2-3 days). Embryos in eggs that were produced at Earth gravity and continued their development on the centrifuge at fields of 2 G or less did not appear to be greatly affected by the treatment. At 4 G, 91% of the embryos died, mostly on the first and second days of incubation. Abnormalities prominent in the centrifuged eggs include: (a) a failure of the primitive streak to develop; (b) interference with the development of the axial skeleton; (c) multiple hemorrhages, mostly petechial which is consistent with capillary fragility; and (d) retardation of embryo growth, possibly caused by an interference with gaseous diffusion, the result of an acceleration-induced increase in gas density in the centrifuging incubator

AlGaAs-GaAs cascade solar cell

Computer modeling studies are reported for a monolithic, two junction, cascade solar cell using the AlGaAs GaAs materials combination. An optimum design was obtained through a serial optimization procedure by which conversion efficiency is maximized for operation at 300 K, AM 0, and unity solar concentration. Under these conditions the upper limit on efficiency was shown to be in excess of 29 percent, provided surface recombination velocity did not exceed 10,000 cm/sec

A route generator concept for aircraft onboard fault monitoring

Because of the increasingly complex environments in which the flight crews of commercial aviation aircraft must operate, a research effort is currently underway at NASA Langley Research Center to investigate the potential benefits of intelligent cockpit aids, and to establish guidelines for the application of artificial intelligence techniques to advanced flight management concepts. The segment of this research area that concentrates on automated fault monitoring and diagnosis requires that a reference frame exist, against which the current state of the aircraft may be compared to determine the existence of a fault. This paper describes a computer program which generates the position of that reference frame that specifies the horizontal flight route

Phosphorylation and protonation of neighboring MiRP2 sites: function and pathophysiology of MiRP2-Kv3.4 potassium channels in periodic paralysis.

MinK-related peptide 2 (MiRP2) and Kv3.4 subunits assemble in skeletal muscle to create subthreshold, voltage-gated potassium channels. MiRP2 acts on Kv3.4 to shift the voltage dependence of activation, speed recovery from inactivation, suppress cumulative inactivation and increase unitary conductance. We previously found an R83H missense mutation in MiRP2 that segregated with periodic paralysis in two families and diminished the effects of MiRP2 on Kv3.4. Here we show that MiRP2 has a single, functional PKC phosphorylation site at serine 82 and that normal MiRP2-Kv3.4 function requires phosphorylation of the site. The R83H variant does not prevent PKC phosphorylation of neighboring S82; rather, the change shifts the voltage dependence of activation and endows MiRP2-Kv3.4 channels with sensitivity to changes in intracellular pH across the physiological range. Thus, current passed by single R83H channels decreases as internal pH is lowered (pK(a) approximately 7.3, consistent with histidine protonation) whereas wild-type channels are largely insensitive. These findings identify a key regulatory domain in MiRP2 and suggest a mechanistic link between acidosis and episodes of periodic paralysis