Half-BPS SU(N) Correlators in N=4 SYM

In this note we study half-BPS operators in N=4 super Yang-Mills for gauge group SU(N) at finite N. In particular we elaborate on the results of hep-th/0410236, providing an exact formula for the null basis operators algorithmically constructed there. For gauge groups U(N) and SU(N) we show that this basis is dual to the basis of multi-trace operators with respect to the two point function. We use this to extend the results of hep-th/0611290 concerning factorisation and probabilities from U(N) to SU(N). We also give a construction for a separate diagonal basis of the SU(N) operators in terms of the higher Hamiltonians of the complex matrix model reduction of this sector.Comment: LaTeX, 15 pages; comments added on large N limi

Skylab astronaut life support assembly

A comparative study was performed to define an optimum portable life support system for suited operations inside and outside the Skylab Program. Emphasis was placed on utilization of qualified equipment, modified versions of qualified equipment, and new systems made up to state-of-the-art components. Outlined are the mission constraints, operational modes, and evaluation ground rules by which the Skylab portable life support system was selected and the resulting design

The BHB stars in the Survey Fields of Rodgers et al. (1993): New Observations and Comparisons with other Recent Surveys

We study blue horizontal branch (BHB) and RR Lyrae stars in the Rogers et al. (1993a) fields and compare their velocity and density distributions with other surveys in the same part of the sky. Photometric data are given for 176 early-type stars in the northern field. We identify fourteen BHB stars and four possible BHB stars, and determine the selection efficiency of the Century Survey, the HK Survey, and the SDSS survey for BHB stars. We give light curves and \gamma -radial velocities for three type-ab RR Lyrae stars in the northern field; comparison with the nearby LONEOS Survey shows that there is likely to be an equal number of lower-amplitude type-ab RR Lyrae stars that we do not find. There are therefore at least twice as many BHB stars as type-ab RR Lyrae stars in the northern field--similar to the ratio in the solar neighborhood. The velocity distribution of the southern field shows no evidence for an anomalous thick disk that was found by Gilmore et al. (2002); the halo velocity peaks at a slightly prograde rotational velocity but there is also a significant retrograde halo component in this field. The velocity distribution in the northern field shows no evidence of Galactic rotation for |Z|>4 kpc and a slight prograde motion for |Z|<4 kpc. The space densities of BHB stars in the northern field agree with an extrapolation of the power-law distribution recently derived by de Propris et al. (2010). For |Z|<4 kpc, however, we observe an excess of BHB stars compared with this power-law. We conclude that these BHB stars mostly belong to a spatially flattened, non-rotating inner halo component of the Milky Way in confirmation of the Kinman et al. (2009) analysis of Century Survey BHB stars.Comment: 24 pages, accepted in A

On vortex/wave interactions. Part 2. Originating from axisymmetric flow with swirl

Following the study in Part 1 of cross-flow and other non-symmetric effects on vortex/wave interactions in boundary layers, the present Part 2 applies the ideas of Part 1 and related works to an incident axisymmetric flow supplemented by a small swirl or azimuthal velocity. This is with a view to possibly increasing understanding of vortex breakdown. The wave components involved are predominantly inviscid Rayleigh-like ones. The presence of the swirl leads to extra features and complications associated mainly with extra logarithmic contributions but for the dominant interactions essentially the same equations as in Part 1 are found. These dominant nonlinear interactions must be based on azimuthal wavenumbers of +/-1 in the case of the Squire jet with swirl. In contrast to Part 1, which consisted mainly of an analysis of the quasi-bounded solutions, a representative set of numerical solutions of the full integro-differential amplitude equations is presented, for realistic axial and swirl velocity profiles. The work points also to the influence of further increases in the incident swirl

Control of virtual environments for young people with learning difficulties

Purpose: The objective of this research is to identify the requirements for the selection or development of usable virtual environment (VE) interface devices for young people with learning disabilities. Method: a user-centred design methodology was employed, to produce a design specification for usable VE interface devices. Details of the users' cognitive, physical and perceptual abilities were obtained through observation and normative assessment tests. Conclusions : A review of computer interface technology, including virtual reality and assistive devices, was conducted. As there were no devices identified that met all the requirements of the design specification, it was concluded that there is a need for the design and development of new concepts. Future research will involve concept and prototype development and user-based evaluation of the prototypes

Tensor interaction contributions to single-particle energies

We calculate the contribution of the nucleon-nucleon tensor interaction to single-particle energies with finite-range $G$ matrix potentials and with zero-range Skyrme potentials. The Skx Skyrme parameters including the zero-range tensor terms with strengths calibrated to the finite-range results are refitted to nuclear properties. The fit allows the zero-range proton-neutron tensor interaction as calibrated to the finite-range potential results and that gives the observed change in the single-particle gap $\epsilon$(h$_{11/2}$)-$\epsilon$(g$_{7/2}$) going from $^{114}$Sn to $^{132}$Sn. However, the experimental $\ell$ dependence of the spin-orbit splittings in $^{132}$Sn and $^{208}$Pb is not well described when the tensor is added, due to a change in the radial dependence of the total spin-orbit potential. The gap shift and a good fit to the $\ell$-dependence can be recovered when the like-particle tensor interaction is opposite in sign to that required for the $G$ matrix.Comment: 5 pages, 4 figures, accepted for publication as Rapid Communication in Physical Review

FEMA’s Public Assistance Grant Program: Background and Considerations for Congress

[Excerpt] The Robert T. Stafford Disaster Relief and Emergency Assistance Act (42 U.S.C. 5121 et seq., henceforth the Stafford Act) confers upon the President a broad set of authorities “to alleviate the suffering and damage” of affected tribal, state, and local governments, as well as individual citizens, from disasters. The Federal Emergency Management Agency (FEMA) of the Department of Homeland Security (DHS) has been given the responsibility of administering almost all of the President’s Stafford Act authorities through other law, a series of Executive Orders, and a DHS delegation. FEMA has established the Public Assistance (PA) Grant Program by combining the authority of multiple sections of the Stafford Act. The PA Program provides financial grant assistance to states, tribes, and local communities both in the response to and recovery from significant disasters. Between FY2000-FY2013, the PA Program has provided $52.6 billion in grant assistance to help communities pay for an array of eligible response and recovery activities, including debris removal, emergency protective measures, and the repair, replacement, or restoration of disaster-damaged, publicly owned facilities and the facilities of certain private nonprofit (PNP) organizations. The authorities of the PA Program were most recently significantly amended by the Sandy Recovery Improvement Act (Division B of P.L. 113- 2, the Disaster Relief Appropriations Act, 2013; henceforth SRIA). For a brief legislative history of PA Program authorities, see Appendix A. This report provides background on key elements of the PA Program, such as the eligibility of applicants, the types of assistance available, and the methods FEMA uses for awarding grant assistance. Summary analysis of federal obligations for PA Program assistance is also provided along important variables, such as the distribution of federal obligations across the PA Program eligible categories of work assistance. The report concludes with discussion of several policy issues that Congress may wish to consider when evaluating the PA Program in the future, including considerations of significant prospective changes to the PA Program and the role of the PA Program in the context of other federal agency disaster assistance authorities