ECONOMIES OF SIZE AMONG MUNICIPAL WATER AUTHORITIES IN PENNSYLVANIA

Resource /Energy Economics and Policy,

Electromagnetic cascades in pulsars

The development of pair photon cascades initiated by high energy electrons above a pulsar polar cap is simulated numerically. The calculation uses the energy of the primary electron, the magnetic field strength, and the period of rotation as parameters and follows the curvature radiation emitted by the primary, the conversion of this radiation e(+) - e(-) pairs in the intense fields, and the quantized synchrotron radiation by the secondary pairs. A recursive technique allows the tracing of an indefinite number of generations using a Monte Carlo method. Gamma ray and pair spectra are calculated for cascades in different parts of the polar cap and with different acceleration models. It is found that synchrotron radiation from secondary pairs makes an important contribution to the gamma ray spectrum above 25 MeV, and that the final gamma ray and pair spectra are insensitive to the height of the accelerating region, as long as the acceleration of the primary electrons is not limited by radiation reaction

Pair production in superstrong magnetic fields

The production of electron-positron pairs by single photons in magnetic fields 10 to the twelth power G was investigated in detail for photon energies near threshold as well as for the asymptotic limit of high photon energy. The exact attenuation coefficient, which is derived and then evaluated numerically, is strongly influenced by the discrete energy states of the electron and positron. Near threshold, it exhibits a sawtooth pattern as a function of photon energy, and its value is significantly below that predicted by the asymptotic expression for the attenuation coefficient. The energy distributions of the created pair are computed numerically near threshold and analytic expressions are derived in the asymptotic limit. These results indicate that as field strength and photon energy increase, it becomes increasingly probable for the pair to divide the photon energy unequally. This effect, as well as the threshold behavior of the attenuation coefficient, could have important consequences for pulsar models

The hGFAP-driven conditional TSPO knockout is protective in a mouse model of multiple sclerosis.

The mitochondrial translocator protein (TSPO) has been implicated in CNS diseases. Here, we sought to determine the specific role of TSPO in experimental autoimmune encephalomyelitis (EAE), the most studied animal model of multiple sclerosis (MS). To fundamentally elucidate the functions of TSPO, we first developed a viable TSPO knockout mouse. A conditional TSPO knockout mouse was generated by utilizing the Cre-Lox system. We generated a TSPO floxed mouse, and then crossed this mouse with a Cre recombinase expressing mouse driven by the human glial fibrillary acidic protein (hGFAP) promoter. The resultant mouse was a neural linage line specific TSPO knockout. The loss of TSPO in the CNS did not result in overt developmental defects or phenotypes. The TSPO-/- mouse showed a decrease in GFAP expression, correlating with a decrease in astrogliosis in response to neural injury during EAE. This decrease in astrogliosis was also witnessed in the lessening of severity of EAE clinical scoring, indicating an in vivo functional role for TSPO in suppressing EAE. The TSPO-/- mouse could be a useful tool in better understanding the role of TSPO in CNS disease, and our results implicate TSPO as a potential therapeutic target in MS

Experiments on the injection and containment of electron clouds in a toroidal apparatus

Injection and containment of electron clouds in azimuthally symmetric, toroidal apparatu

Automated measurement of the bit-error rate as a function of signal-to-noise ratio for microwave communications systems

The performance of microwave systems and components for digital data transmission can be characterized by a plot of the bit-error rate as a function of the signal to noise ratio (or E sub b/E sub o). Methods for the efficient automated measurement of bit-error rates and signal-to-noise ratios, developed at NASA Lewis Research Center, are described. Noise measurement considerations and time requirements for measurement accuracy, as well as computer control and data processing methods, are discussed

Executive Secrets: Covert Action and the Presidency

A frank and refreshing evaluation of several Chief Executives, their Directors of Central Intelligence, and even some lower in the hierarchy, Executive Secrets shines light on the development and execution of foreign policy through the understanding of the tools available, of which covert action may be least known and understood. This book is a great tool for the press, the public, and many political appointees in the National Security System. A History Book Club Selection with a foreword by Mark Bowden, author of Black Hawk Down. [Daugherty] gives a frank and refreshing evaluation of several Chief Executives, their Directors of Central Intelligence, and even some lover in the hierarchy. Anyone interested or involved in the development and execution of foreign policy must know the tools available, of which covert action may be least known and understood. This understanding is also pertinent to a wider audience: the press, the public, and many political appointees in the National Security system. This book should help. -- Air Power History A most informative study of covert action.... This well-researched, thoughtful book is a valuable work that will be treasured by scholars and professionals in the field. Highly recommended. -- Choice A hard-hitting, balanced and highly successful effort to deal with the issue of presidential responsibility for covert action. -- John Stempel, Patterson School of Diplomacy, University of Kentucky Daugherty has done us all a tremendous service by attempting to rescue the Agency from the myths, both well-meaning and malevolent, that shape our understanding of it. . . . This book ought to dispel some of the fog that obscures our understanding of the C.I.A. and that prompts the gigantic mood swings in our attitude toward intelligence gathering and covert actions. -- Mark Bowden, from the foreword There are some interesting and carefully drawn vignettes of covert operations here that demonstrate a skillful blending of declassified documents, investigative reports, and secondary sources. It is these case studies that make this one of those essential works for specialists in intelligence policy. -- Register of the Kentucky Historical Society If you are a keen observer of the agency, this one will interest and instruct you. -- Rockland (ME) Courier-Gazette Offers a richly textured book that clears up some common misconceptions of the CIA, as well as an insider\u27s perspective on how covert action really works, or fails. -- Savannah (GA) Morning News Readers of this timely and occasionally revelatory account may be surprised to learn that President Carter approved a covert action program to attack the internal legitimacy of the Soviet system, and that he repeatedly relied on covert action to achieve his foreign policy aims. -- Zbigniew Brzezinski Named a 2005 Choice Outstanding Academic Title. [Daugherty] has done a great service for those wanting to seriously understand the realistic capabilities of the organization. This is not an easy task, for the CIA has been the subject of many books, movies, and certain mindsets in the population. --Foreign Area Officer Journalhttps://uknowledge.uky.edu/upk_political_science_american_politics/1038/thumbnail.jp

An ion resonance instability in grossly non-neutral plasmas

Ion resonance instability in grossly non-neutral plasma

Mapping engineering concepts for secondary level education

Much of the national attention on science, technology, engineering, and mathematics (STEM) education tends to concentrate on science and mathematics, with its emphasis on standardized test scores. However as the National Academy of Engineering Committee on K-12 Engineering Education stressed, engineering can contribute to the development of an effective and interconnected STEM education system (Katehi, Pearson, & Feder, 2009). In addition, engineering can provide authentic learning contexts for science, technology, and mathematics. Numerous K-12 engineering initiatives have emerged across the U.S. developing curriculum and conducting teacher professional development (Brophy, Klein, Portsmore, & Rogers, 2008). The focus of pre-college engineering education has largely been on process, with engineering content or concepts playing at best a secondary role. The Standards for Technological Literacy (STL) (2000), for example, has been cited by many as providing direction for pre-college engineering, with its design-oriented standards. However, the STL do not specify engineering content and focuses only on the design process. In addition, numerous studies have been conducted to identify engineering-oriented outcomes and competencies (Childress & Rhodes, 2008; Dearing & Daugherty, 2004; Harris & Rogers, 2008). However, these studies have resulted in lists that focus heavily on process and the interpersonal skills associated with engineering (communication, teamwork, etc.). For example, Childress and Sanders (2007) examined the related literature and engineering curricular materials, concluding that it is “challenging to create a framework that might be helpful in developing „engineering‟ instructional materials for secondary schools.