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The electric power delivery system that carries electricity from
large central generators to customers could be severely damaged by
a small number of well-informed attackers. The system is inherently
vulnerable because transmission lines may span hundreds of miles,
and many key facilities are unguarded. This vulnerability is
exacerbated by the fact that the power grid, most of which was
originally designed to meet the needs of individual vertically
integrated utilities, is being used to move power between regions
to support the needs of competitive markets for power generation.
Primarily because of ambiguities introduced as a result of recent
restricting the of the industry and cost pressures from consumers
and regulators, investment to strengthen and upgrade the grid has
lagged, with the result that many parts of the bulk high-voltage
system are heavily stressed.
Prepared by the Task Committee on Wood Pole Structures for Electrical Transmission Lines of the Committee on Electrical Transmission Structures of the Structural Engineering Institute of ASCE.Wood Pole Structures for Electrical Transmission Lines: Recommended Practice for Design and Use, MOP 141, provides comprehensive knowledge of the principles and methods for the design and use of wood poles for overhead utility line structures. The use of wood pole structures, properly designed utilizing consistent structural engineering principles, may provide a simple, cost effective, and more resilient option than some of the other pole materials commonly used. This manual examines Structural configurations and pole applications; Critical factors and design considerations specific to wood pole structures; Mechanical properties, applicable standards and specifications used to manufacture wood poles; Wood pole foundations and anchoring; Construction of wood pole structures; and Inspection and maintenance of wood pole structures and lines. This Manual of Practice will be valuable to engineers involved in utility, electrical, and structural engineering.
During the early years of the AIDS epidemic, thousands of Americans
became infected with HIV through the nation's blood supply. Because
little reliable information existed at the time AIDS first began
showing up in hemophiliacs and in others who had received
transfusions, experts disagreed about whether blood and blood
products could transmit the disease.
Americans' safety, productivity, comfort, and convenience depend on the reliable supply of electric power. The electric power system is a complex aEUROoecyber-physicalaEURO system composed of a network of millions of components spread out across the continent. These components are owned, operated, and regulated by thousands of different entities. Power system operators work hard to assure safe and reliable service, but large outages occasionally happen. Given the nature of the system, there is simply no way that outages can be completely avoided, no matter how much time and money is devoted to such an effort. The system's reliability and resilience can be improved but never made perfect. Thus, system owners, operators, and regulators must prioritize their investments based on potential benefits. Enhancing the Resilience of the Nation's Electricity System focuses on identifying, developing, and implementing strategies to increase the power system's resilience in the face of events that can cause large-area, long-duration outages: blackouts that extend over multiple service areas and last several days or longer. Resilience is not just about lessening the likelihood that these outages will occur. It is also about limiting the scope and impact of outages when they do occur, restoring power rapidly afterwards, and learning from these experiences to better deal with events in the future.
In 2009, the H1N1 influenza pandemic brought to the forefront the many unknowns about the virulence, spread, and nature of the virus, as well as questions regarding personal protective equipment (PPE) for healthcare personnel. In this book, the Institute of Medicine assesses the progress of PPE research and identifies future directions for PPE for healthcare personnel.
A major goal of the Federal Aviation Administration (FAA), and now the Transportation Security Administration (TSA), is the development of technologies for detecting explosives and illegal drugs in freight cargo and passenger luggage. One such technology is pulsed fast neutron analysis (PFNA). This technology is based on detection of signature radiation (gamma rays) induced in material scanned by a beam of neutrons. While PFNA may have the potential to meet TSA goals, it has many limitations. Because of these issues, the government asked the National Research Council to evaluate the potential of PFNA for airport use and compare it with current and future x-ray technology. The results of this survey are presented in "Assessment of the Practicality of Pulsed Fast Neutron Analysis for Aviation Security.? A broad range of detection methods and test results are covered in this report. Tests conducted as of October 2000 showed that the PFNA system was unable to meet the stringent federal aviation requirements for explosive detection in air cargo containers. PFNA systems did, however, demonstrate some superior characteristics compared to existing x-ray systems in detecting explosives in cargo containers, though neither system performed entirely satisfactorily. Substantial improvements are needed in the PFNA detection algorithms to allow it to meet aviation detection standards for explosives in cargo and passenger baggage. The PFNA system currently requires a long scan time (an average of 90 minutes per container in the prototype testing in October 2000), needs considerable radiation shielding, is significantly larger than current x-ray systems, and has high implementation costs. These factors are likely to limit installation at airports, even if the detection capability is improved. Nevertheless, because PFNA has the best potential of any known technology for detecting explosives in cargo and luggage, this book discusses how continued research to improve detection capabilities and system design can best be applied for the airport environment.
Mitochondrial replacement techniques (MRTs) are designed to prevent the transmission of mitochondrial DNA (mtDNA) diseases from mother to child. While MRTs, if effective, could satisfy a desire of women seeking to have a genetically related child without the risk of passing on mtDNA disease, the technique raises significant ethical and social issues. It would create offspring who have genetic material from two women, something never sanctioned in humans, and would create mitochondrial changes that could be heritable (in female offspring), and therefore passed on in perpetuity. The manipulation would be performed on eggs or embryos, would affect every cell of the resulting individual, and once carried out this genetic manipulation is not reversible. Mitochondrial Replacement Techniques considers the implications of manipulating mitochondrial content both in children born to women as a result of participating in these studies and in descendants of any female offspring. This study examines the ethical and social issues related to MRTs, outlines principles that would provide a framework and foundation for oversight of MRTs, and develops recommendations to inform the Food and Drug Administration's consideration of investigational new drug applications.
Thousands of HIV-positive women give birth every year. Further,
because many pregnant women are not tested for HIV and therefore do
not receive treatment, the number of children born with HIV is
still unacceptably high. What can we do to eliminate this tragic
and costly inheritance? In response to a congressional request,
this book evaluates the extent to which state efforts have been
effective in reducing the perinatal transmission of HIV. The
committee recommends that testing HIV be a routine part of prenatal
care, and that health care providers notify women that HIV testing
is part of the usual array of prenatal tests and that they have an
opportunity to refuse the HIV test. This approach could help both
reduce the number of pediatric AIDS cases and improve treatment for
mothers with AIDS.
In Advancing Prion Science, the Institute of Medicinea (TM)s Committee on Transmissible Spongiform Encephalopathies Assessment of Relevant Science recommends priorities for research and investment to the Department of Defensea (TM)s National Prion Research Program (NPRP). Transmissible spongiform encephalopathies (TSEs), also called prion diseases, are invariably fatal neurodegenerative infectious diseases that include bovine spongiform encephalopathy (commonly called mad cow disease), chronic wasting disease, scrapie, and Creutzfeldt-Jakob disease. To develop antemortem diagnostics or therapies for TSEs, the committee concludes that NPRP should invest in basic research specifically to elucidate the structural features of prions, the molecular mechanisms of prion replication, the mechanisms of TSE pathogenesis, and the physiological function of prionsa (TM) normal cellular isoform. Advancing Prion Science provides the first comprehensive reference on present knowledge about all aspects of TSEsa "from basic science to the U.S. research infrastructure, from diagnostics to surveillance, and from prevention to treatment.
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