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Without major changes, the current air transportation system will be unable to accommodate the expected increase in demand by 2025. One proposal to address this problem is to use the Global Positioning System to enable aircraft to fly more closely spaced. This approach, however, might be limited by the wake turbulence problem, which can be a safety hazard when smaller aircraft follow relatively larger aircraft too closely. To examine how this potential hazard might be reduced, Congress in 2005 directed NASA to request a study from the NRC to assess the federal wake turbulence R&D program. This book provides a description of the problem, an assessment of the organizational challenges to addressing wake turbulence, an analysis of the technical challenges in wake turbulence, and a proposal for a wake turbulence program plan. A series of recommendations for addressing the wake turbulence challenge are also given.
In December 2002, a group of specialists on water resources from the United States and Iran met in Tunis, Tunisia, for an interacademy workshop on water resources management, conservation, and recycling. This was the fourth interacademy workshop on a variety of topics held in 2002, the first year of such workshops. Tunis was selected as the location for the workshop because the Tunisian experience in addressing water conservation issues was of interest to the participants from both the United States and Iran. This report includes the agenda for the workshop, all of the papers that were presented, and the list of site visits.
National interests in greater energy independence, concurrent with favorable market forces, have driven increased production of corn-based ethanol in the United States and research into the next generation of biofuels. The trend is changing the national agricultural landscape and has raised concerns about potential impacts on the nation's water resources. To help illuminate these issues, the National Research Council held a colloquium on July 12, 2007 in Washington, DC. <i>Water Implications of Biofuels Production in the United States</i>, based in part on discussions at the colloquium, concludes that if projected future increases in use of corn for ethanol production do occur, the increase in harm to water quality could be considerable from the increases in fertilizer use, pesticide use, and soil erosion associated with growing crops such as corn. Water supply problems could also develop, both from the water needed to grow biofuels crops and water used at ethanol processing plants, especially in regions where water supplies are already overdrawn. The production of "cellulosic ethanol," derived from fibrous material such as wheat straw, native grasses, and forest trimmings is expected to have less water quality impact but cannot yet be produced on a commerical scale. To move toward a goal of reducing water impacts of biofuels, a policy bridge will likely be needed to encourage growth of new technologies, best agricultural practies, and the development of traditional and cellulosic crops that require less water and fertilizer and are optimized for fuel production.
The U.S. Army Corps of Engineers recently completed its feasibility study for the Upper Mississippi River-Ilinois Waterway, which was one of the agency's longest and most complicated studies in its history. The first two reports from this WSTB committee reviewed analytical aspects of the Corps feasibility study. This report considered the broader issue of managing the multiple resources of the Upper Mississippi River and Illinois Waterway, especially with regard to several, recently-issued NRC reports on Corps of Engineers planning procedures. The report finds that a key issue regarding planning decisions on these river systems is the ambiguity related to several different pieces of legislation and acts that govern river management, and thus recommends that the administration and Congress clarify the federal intent for managing this river and waterway system. The report recommends an independent, retrospective reivew of the experience with a federal inter-agency Principals Group, which was convened to provide guidance to the Corps study. It is also recommended that the Corps strive to incorporate flexible, adaptive management principles through its entire water planning program, including operations of the lock and dam system.
As women of childbearing age have become heavier, the trade-off between maternal and child health created by variation in gestational weight gain has become more difficult to reconcile. Weight Gain During Pregnancy responds to the need for a reexamination of the 1990 Institute of Medicine guidelines for weight gain during pregnancy. It builds on the conceptual framework that underscored the 1990 weight gain guidelines and addresses the need to update them through a comprehensive review of the literature and independent analyses of existing databases. The book explores relationships between weight gain during pregnancy and a variety of factors (e.g., the mother's weight and height before pregnancy) and places this in the context of the health of the infant and the mother, presenting specific, updated target ranges for weight gain during pregnancy and guidelines for proper measurement. New features of this book include a specific range of recommended gain for obese women. Weight Gain During Pregnancy is intended to assist practitioners who care for women of childbearing age, policy makers, educators, researchers, and the pregnant women themselves to understand the role of gestational weight gain and to provide them with the tools needed to promote optimal pregnancy outcomes.
By 2030 there will be about 70 million people in the United States who are older than 64. Approximately 26 percent of these will be racial and ethnic minorities. Overall, the older population will be more diverse and better educated than their earlier cohorts. The range of late-life outcomes is very dramatic with old age being a significantly different experience for financially secure and well-educated people than for poor and uneducated people. The early mission of behavioral science research focused on identifying problems of older adults, such as isolation, caregiving, and dementia. Today, the field of gerontology is more interdisciplinary. When I'm 64 examines how individual and social behavior play a role in understanding diverse outcomes in old age. It also explores the implications of an aging workforce on the economy. The book recommends that the National Institute on Aging focus its research support in social, personality, and life-span psychology in four areas: motivation and behavioral change; socioemotional influences on decision-making; the influence of social engagement on cognition; and the effects of stereotypes on self and others. When I'm 64 is a useful resource for policymakers, researchers and medical professionals.
The past 15 years have seen marked progress in observing, understanding, and predicting weather. At the same time, the United States has failed to match or surpass progress in operational numerical weather prediction achieved by other nations and failed to realize its prediction potential; as a result, the nation is not mitigating weather impacts to the extent possible. This book represents a sense of the weather community as guided by the discussions of a Board on Atmospheric Sciences and Climate community workshop held in summer 2009. The book puts forth the committee's judgment on the most pressing high level, weather-focused research challenges and research to operations needs, and makes corresponding recommendations. The book addresses issues including observations, global non-hydrostatic coupled modeling, data assimilation, probabilistic forecasting, and quantitative precipitation and hydrologic forecasting. The book also identifies three important, emerging issues--predictions of very high impact weather, urban meteorology, and renewable energy development--not recognized or emphasized in previous studies. Cutting across all of these challenges is a set of socioeconomic issues, whose importance and emphasis--while increasing--has been undervalued and underemphasized in the past and warrants greater recognition and priority today.
The use of radio-frequency communication--commonly referred to as wireless communication--is becoming more pervasive as well as more economically and socially important. Technological progress over many decades has enabled the deployment of several successive generations of cellular telephone technology, which is now used by many billions of people worldwide; the near-universal addition of wireless local area networking to personal computers; and a proliferation of actual and proposed uses of wireless communications. The flood of new technologies, applications, and markets has also opened up opportunities for examining and adjusting the policy framework that currently governs the management and use of the spectrum and the institutions involved in it, and models for allocating spectrum and charging for it have come under increasing scrutiny. Yet even as many agree that further change to the policy framework is needed, there is debate about precisely how the overall framework should be changed, what trajectory its evolution should follow, and how dramatic or rapid the change should be. Many groups have opinions, positions, demands, and desires related to these questions--reflecting multiple commercial, social, and political agendas and a mix of technical, economic, and social perspectives. The development of technologies and associated policy and regulatory regimes are often closely coupled, an interplay apparent as early as the 1910s, when spectrum policy emerged in response to the growth of radio communications. As outlined in this report, current and ongoing technological advances suggest the need for a careful reassessment of the assumptions that inform spectrum policy in the United States today. This book seeks to shine a spotlight on 21st-century technology trends and to outline the implications of emerging technologies for spectrum management in ways that the committee hopes will be useful to those setting future spectrum policy.
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