Relations for classical communication capacity and entanglement capability of two-qubit operations

Bipartite operations underpin both classical communication and entanglement generation. Using a superposition of classical messages, we show that the capacity of a two-qubit operation for error-free entanglement-assisted bidirectional classical communication can not exceed twice the entanglement capability. In addition we show that any bipartite two-qubit operation can increase the communication that may be performed using an ensemble by twice the entanglement capability.Comment: 4 page

Parent Anxiety Causes and Consequences: Perspectives from Camp Program Providers

Although out-of-school time experiences such as camp contribute to youth development, youth in-volvement in these developmental experiences is largely dependent on parents who determine which activities are appropriate for their children. A contributing factor to parents’ decisions to send their child to camp is the amount of risk and non-clinical anxiety that parents associate with the camp experience, yet little attention has been paid to these issues, particularly from the perspective of camp program providers. It is unclear to what extent parent anxiety is an operational and pro-grammatic concern for camp program providers. Informed by risk perception and parent involve-ment theories, this study explores (1) causes of parent anxiety from the perspective of camp pro-gram providers; (2) operational and programmatic consequences associated with the management of parent anxiety; and (3) camp program practices used to reduce parent anxiety. Data were collect-ed from a sample of 248 camp program providers who completed an online survey that included open-ended questions related to perceptions and observations of parent anxiety, as well as strate-gies used to manage parents. Content analysis was used to code the data and to construct themes. Constructed themes suggested that parent anxiety is associated with parent-child separation, limited parent camp experience, lack of parent trust, the expression of overparenting behaviors, fear of lack of safety, and insufficient preparation. Constructed themes associated with operational or program-matic changes indicated that camp program providers use a range of strategies to reduce parent anxiety, broadly summarized as communication, staffing, access, and education. Implications for practice and future directions are explored

Getting Started: Using a Global Circumnavigation Balloon Flight to Explore Picosatellite (CubeSat) Technology

Washington University\u27s Project Aria is currently involved in the CubeSat program. Project Aria is a student-led engineering education, research, and K-12 outreach program. The project’s CubeSat goal is the development of a spherical imaging spacecraft, the Palantir , ready for launch in late 2002. Recently, the Palantir team was offered the opportunity to fly a small payload on a global circumnavigation balloon flight in mid-2001. The payload would collect atmospheric data such as temperature, pressure, and humidity. The student team decided to use this opportunity to explore various technologies they plan for Palantir. This resulting in a fast, challenging engineering project that developed the skills needed for a successful picosatellite project. The technologies to be explored include a self-contained power system with solar cells, on-board computers, on-board cameras, various sensors, satellite communications, and mission operations. One specific test involves mounting temperature sensors throughout the probe. The students will then compare actual thermal reading to predicted thermal readings. Other specific tests will involve the use of several different types of solar cells to judge performance. Finally, students will remotely operate the payload as they would the satellite to explore operating concepts and tools. This balloon opportunity allows students the chance to explore various technologies and operating concepts needed for a successful satellite program without the high cost of a launch. This paper briefly describes the Palantir CubeSat program, the Palantir Technology Demonstration balloon program, and the results of the flight. Particular attention is paid to goals of the balloon flight and a review of the successes and failures. Lessons learned from the test flight can be applied to other universities seeking to develop CubeSats and other project-based programs

Interconvertibility of single-rail optical qubits

We show how to convert between partially coherent superpositions of a single photon with the vacuum using linear optics and postselection based on homodyne measurements. We introduce a generalized quantum efficiency for such states and show that any conversion that decreases this quantity is possible. We also prove that our scheme is optimal by showing that no linear optical scheme with generalized conditional measurements, and with one single-rail qubit input can improve the generalized efficiency.Comment: 3 pages, 2 figure

Monogamy and polygamy for multi-qubit entanglement using R\'enyi entropy

Using R\'enyi-$\alpha$ entropy to quantify bipartite entanglement, we prove monogamy of entanglement in multi-qubit systems for $\alpha \geq 2$. We also conjecture a polygamy inequality of multi-qubit entanglement with strong numerical evidence for $0.83-\epsilon \leq \alpha \leq 1.43+\epsilon$ with $0<\epsilon<0.01$.Comment: 19 pages, 2 figure

On the geometric distance between quantum states with positive partial transposition and private states

We prove an analytic positive lower bound for the geometric distance between entangled positive partial transpose (PPT) states of a broad class and any private state that delivers one secure key bit. Our proof holds for any Hilbert space of finite dimension. Although our result is proven for a specific class of PPT states, we show that our bound nonetheless holds for all known entangled PPT states with non-zero distillable key rates whether or not they are in our special class.Comment: 16 page

PROJECTING THE IMPACT OF DEMOGRAPHIC CHANGE ON THE DEMAND FOR AND DELIVERY OF HEALTH CARE IN IRELAND. RESEARCH SERIES NUMBER 13 OCTOBER 2009

Primary care is often the first point of contact with the health care system for people requiring care. Primary care is often thought synonymous with general practitioners, but actually encompasses a large range of different professionals and services including nurses/midwives; physiotherapists; occupational therapists; dentists; opticians; chiropodists; psychologists and pharmacists. The list is not exhaustive, but still gives an indication of the wide range of services that can be grouped under the general heading of primary care. Nonetheless, GPs do have a core part to play in primary care as well as performing the role of ‘gate keeper’ to other health services such as accident and emergency or outpatient care in hospitals. The balance of treatment and referral between general practice and secondary care is, therefore, a very important issue and it has been argued that the under development of primary care services in Ireland in recent decades has contributed, and indeed, may be the most important reason, for the over-crowding of accident and emergency services and long waiting lists for elective procedures in Irish health care (Layte et al., 2007b; Tussing and Wren, 2006)

Book Reviews

Reviews of the following books: History of Belfast in the 20th Century: by Jay David and Tim Hughes, with Megan Pinette; At Home With The General: A Visit to the Joshua L. Chamberlain Museum by Allan M. Levinsky; “Do Your Job!” An Illustrated Bicentennial History of the Portsmouth Naval Shipyard, 1800-2000 by Richard E. Winslow, III; Super U: The History and Politics of the University of Maine System by James Libb