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 End of Innocence: Rethinking Noncombatancy in the Post-Kosovo Era

The protection of civilians and their property in war is an accepted norm of international law - even where the putatively noncombatant populace openly supports the immoral use of force by its military. NATO\u27s Kosovo operation suggests, however, that the imposition of hardship on the sentient, adult noncombatant population through property loss can erode a society\u27s appetite for malevolence. While civilians should not be targeted, a new paradigm for noncombatancy that allows the destruction of certain property currently protected by international law but not absolutely indispensable to civilian survival may well help shorten conflict and effect necessary societal change

Cybervandalism or Digital Act of War? America\u27s Muddled Approach to Cyber Incidents Will Not Deter More Crises

If experts say a malicious [cyber] code \u27 has similar effects to a physical bomb, \u27 and that code actually causes a stunning breach of global internet stability, is it really accurate to call that event merely an instance of a cyber attack ? Moreover, can you really expect to deter state and non-state actors from employing such code and similarly hostile cyber methodologies if all they think that they are risking is being labeled as a cyber-vandal subject only to law enforcement measures? Or might they act differently if it were made clear to them that such activity is considered an armed attack \u27 against the United States and that they are in jeopardy of being on the receiving end of a forceful, law-of-war response by the most powerful military on the planet? Of course, if something really is just vandalism, the law enforcement paradigm, with its very limited response options, would suffice. But when malevolent cyber activity endangers the reliability of the internet in a world heavily dependent on a secure cyberspace, it is not merely vandalism. Rather, it is a national and international security threat that ought to be characterized and treated as such. Unfortunately, the United States\u27 current approach is too inscrutable and even contradictory to send an effective deterrence message to potential cyber actors. This needs to change