Lunar composite production

A minimally processed composite material derived from lunar soil and possessing tensile strength is described. Laboratory work and the direction of future work are discussed

Inventory behavior at remote sites

An operations research study was conducted concerning inventory behavior on the space station. Historical data from the Space Shuttle was used. The results demonstrated a high logistics burden if Space Shuttle reliability technology were to be applied without modification to space station design (which it was not). Effects of rapid resupply and on board repair capabilities on inventory behavior were investigated

Health investments and economic growth : macroeconomic evidence and microeconomic foundations

This paper reviews the correlations and potential links between health and economic growth and summarizes the evidence on the role of government in improving health status. At the macroeconomic level, the evidence of an impact of health on growth remains ambiguous due both to difficulties in measuring health, and to the methodological challenges of identifying causal links. The evidence on the micro linkages from health investments to productivity and income are robust. Progress in life expectancy over the past two centuries has been spectacular, fueled by: improved agriculture that has increased food quantity; knowledge of disease transmission, and effective public health interventions that have controlled communicable diseases such as malaria, yellow fever, and hookworm; and, most recently and importantly, investments in very young children that pay off in healthier and more productive adults. Whether public investments in medical care affect health hinges on the quality of health institutions. In much of the developing world, factors such as chronic absenteeism among public providers, poor budget execution, ineffective management, and virtually no accountability weaken public efforts. Institutional issues are central in efforts to enhance public health investments, which in turn have a direct impact on the population's welfare and, perhaps over the long term, improvements in national income.Health Monitoring&Evaluation,Health Systems Development&Reform,Population Policies,Health Economics&Finance,Disease Control&Prevention

Transport: Introduction

Space transportation requirements for the NASA baseline scenario for future space missions are discussed. Spacecraft/propulsion technologies required for surface-to-orbit, orbit-to-orbit, and surface (lunar) transportation are addressed

The shore fishes / by William C. Kendall and Lewis Radcliffe ; with eight plates.

v.35:no.3 (1912

Hybrid LZW compression

The Science Data Management and Science Payload Operations subpanel reports from the NASA Conference on Scientific Data Compression (Snowbird, Utah in 1988) indicate the need for both lossless and lossy image data compression systems. The ranges developed by the subpanel suggest ratios of 2:1 to 4:1 for lossless coding and 2:1 to 6:1 for lossy predictive coding. For the NASA Freedom Science Video Processing Facility it would be highly desirable to implement one baseline compression system which would meet both of these criteria. Presented here is such a system, utilizing an LZW hybrid coding scheme which is adaptable to either type of compression. Simulation results are presented with the hybrid LZW algorithm operating in each of its modes

'Unlicensed' natural killer cells dominate the response to cytomegalovirus infection.

Natural killer (NK) cells expressing inhibitory receptors that bind to self major histocompatibility complex (MHC) class I are 'licensed', or rendered functionally more responsive to stimulation, whereas 'unlicensed' NK cells lacking receptors for self MHC class I are hyporesponsive. Here we show that contrary to the licensing hypothesis, unlicensed NK cells were the main mediators of NK cell-mediated control of mouse cytomegalovirus infection in vivo. Depletion of unlicensed NK cells impaired control of viral titers, but depletion of licensed NK cells did not. The transfer of unlicensed NK cells was more protective than was the transfer of licensed NK cells. Signaling by the tyrosine phosphatase SHP-1 limited the proliferation of licensed NK cells but not that of unlicensed NK cells during infection. Thus, unlicensed NK cells are critical for protection against viral infection

Flow in Computer-Mediated Environments: Strategies for Electronic Commerce on the World Wide Web

The World Wide Web is a hypermedia computer-mediated environment (CME) allowing access to multimedia content through hyperlinks across the Internet. Under conditions of intense use, Web users may experience a state of enhanced interaction known as flow.By customizing Web site content to match individual user characteristics, IS managers can increase user flow and, subsequently, the number of electronic commerce transactions conducted on the site. Descriptions of flow and customized content are developedand propositions with implications for electronic commerce are presented