Are hemispherical caps of boron-nitride nanotubes possible?

We report all-electron, density-functional calculations with large Gaussian polarization basis set of the recently synthesized octahedral B24N24 cage that is perfectly round by symmetry, and boron-nitride (BN) clusters that its existence might suggest. We consider whether it is energetically possible that the two halves of this round cage could cap the BN nanotubes, modeled by B28N28 and B32N32. The energetics show that BN nanotubes with such round caps, are only slightly less favorable than the BN clusters containing six squares as the only defects in the otherwise perfect hexagonal lattice. A larger B96N96 octahedral cage formed from B24N24 by adding sufficient hexagons to isolate all squares is not very favorable energetically. The squares protrude noticeably from its otherwise round surface.Comment: Uses elsart.cls (Elsevier Science), (Better pictures can be obtained from authors); Manuscript to appear in Chemical Physics Letter

Employment Program Models for People Experiencing Homelessness: Different approaches to program structure

Most individuals experiencing or at risk of homelessness want to work and a growing number of service providers and policymakers have taken notice. Although choosing the right employment program model can seem like a daunting task, research and wisdom from the field shows that multiple models have proven effective or promising in attaching the most disadvantaged jobseekers to work and helping them advance to employment options that meet their long-term needs and interests. Additionally, these models can be helpful in building upon existing skills or developing new skills necessary to enter and succeed in employment today. This best practice brief highlights what is known about these employment approaches to attachment and advancement, covering each model's purpose, elements, principles, funding, and research evidence, with examples from the field

Employment Program Components: Considerations for Modifying Programming for People Experiencing Homelessness

Employment programs typically include assessment, job search assistance, work readiness training, occupational training, job placement, and retention services. Research and experience suggest that programs can best meet individual needs, strengths, and interests by modifying these elements to ensure flexible services that support each individual's personal and developmental needs as they transition to employment. This best practice brief highlights a menu of enhancements and examples that programs may consider in providing supportive, flexible services for individuals experiencing or at risk of homelessness

The Police-ization of the Military

This essay will briefly review the background of the use of the armed forces in a police capacity, discuss the growth of that role in the I980s and 1990s, and forecast an even greater expansion into that role in the near future due to the emerging threat of catastrophic terrorism. It will contend that this increased reliance on military resources for policing is not in the interest of either the armed forces or the public. Finally, it will make some observations with a view towards minimizing the dangers of police-ization of the military while ensuring the Nation\u27s public safety

The Military Justice System and Command Accountability

The Long Commission, which investigated the terrorist bombing of the Beirut Marine barracks, recommended punitive action against officers in the chain of command. The president, however, ruled out courts-martial. This article examines the concept of command accountability and the role of the military justice system. Professional dereliction and incompetence have rarely been punished since World War II. . . . Failure to do so has bred an atmosphere of professional unaccountability that encourages, because it does not penalize, repetition of failure on the battlefield