Remark on Z' limits at hadron colliders

Simple estimates for Z' exclusion limits and Z' model measurements in pp (p bar p) collisions are derived. Due to properties of the structure functions, the Z' exclusion limits depend only logarithmically on the Z' couplings to fermions and on the integrated luminosity. The predicted scaling of Z' exclusion limits and errors of Z' measurements with the c.m. energy and luminosity allows an easy extrapolation of existing analyses to other colliders.Comment: 6 pages latex, two figures included by eps

A Cytotoxic, Co-operative Interaction Between Energy Deprivation and Glutamate Release From System x\u3csub\u3ec\u3c/sub\u3e\u3csup\u3e−\u3c/sup\u3e Mediates Aglycemic Neuronal Cell Death

The astrocyte cystine/glutamate antiporter (system xc−) contributes substantially to the excitotoxic neuronal cell death facilitated by glucose deprivation. The purpose of this study was to determine the mechanism by which this occurred. Using pure astrocyte cultures, as well as, mixed cortical cell cultures containing both neurons and astrocytes, we found that neither an enhancement in system xc− expression nor activity underlies the excitotoxic effects of aglycemia. In addition, using three separate bioassays, we demonstrate no change in the ability of glucose-deprived astrocytes—either cultured alone or with neurons—to remove glutamate from the extracellular space. Instead, we demonstrate that glucose-deprived cultures are 2 to 3 times more sensitive to the killing effects of glutamate or N-methyl-D-aspartate when compared with their glucose-containing controls. Hence, our results are consistent with the weak excitotoxic hypothesis such that a bioenergetic deficiency, which is measureable in our mixed but not astrocyte cultures, allows normally innocuous concentrations of glutamate to become excitotoxic. Adding to the burgeoning literature detailing the contribution of astrocytes to neuronal injury, we conclude that under our experimental paradigm, a cytotoxic, co-operative interaction between energy deprivation and glutamate release from astrocyte system xc− mediates aglycemic neuronal cell death

D-Meson Mixing in Broken SU(3)

A fit of amplitudes to the experimental branching ratios to two mesons is used to construct a new estimate of neutral $D$ mixing which includes $SU(3)$ breaking. The result is dominated by the experimental uncertainties. This suggests that the charm sector may not be as sensitive to new physics as previously thought and that long-distance calculations may not be useful.Comment: 12 pages, LaTeX, no figure

Hypersonic Research Vehicle (HRV) real-time flight test support feasibility and requirements study. Part 2: Remote computation support for flight systems functions

The requirements are assessed for the use of remote computation to support HRV flight testing. First, remote computational requirements were developed to support functions that will eventually be performed onboard operational vehicles of this type. These functions which either cannot be performed onboard in the time frame of initial HRV flight test programs because the technology of airborne computers will not be sufficiently advanced to support the computational loads required, or it is not desirable to perform the functions onboard in the flight test program for other reasons. Second, remote computational support either required or highly desirable to conduct flight testing itself was addressed. The use is proposed of an Automated Flight Management System which is described in conceptual detail. Third, autonomous operations is discussed and finally, unmanned operations

Spectroscopy of the optical Einstein ring 0047-2808

We present optical and near-infrared spectroscopic observations of the optical Einstein ring 0047-2808. We detect both [OIII] lines 4959, 5007 near 2.3 micron, confirming the redshift of the lensed source as z=3.595. The Ly-a line is redshifted relative to the [OIII] line by 140+-20 km/s. Similar velocity shifts have been seen in nearby starburst galaxies. The [OIII] line is very narrow, 130 km/s FWHM. If the ring is the image of the centre of a galaxy the one-dimensional stellar velocity dispersion sigma=55 km/s is considerably smaller than the value predicted by Baugh et al. (1998) for the somewhat brighter Lyman-break galaxies. The Ly-a line is significantly broader than the [OIII] line, probably due to resonant scattering. The stellar central velocity dispersion of the early-type deflector galaxy at z=0.485 is 250+-30 km/s. This value is in good agreement both with the value predicted from the radius of the Einstein ring (and a singular isothermal sphere model for the deflector), and the value estimated from the D_n-sigma relation.Comment: 7 pages, 3 figures, accepted for publication in MNRA

Determination of Littlest Higgs model parameters at the ILC

We examine the effects of the extended gauge sector of the Littlest Higgs model in high energy e+e- collisions. We find that the search reach in e+e- -> f fbar at a 500 GeV center-of-mass energy International Linear Collider covers essentially the entire parameter region where the Littlest Higgs model is relevant to the gauge hierarchy problem. In addition, we show that this channel provides an accurate determination of the fundamental model parameters, to the precision of a few percent, provided that the LHC measures the mass of the heavy neutral gauge field. Additionally, we show that the couplings of the extra gauge bosons to the light Higgs can be observed from the process e+e- -> Z higgs for a significant region of the parameter space. This allows for confirmation of the structure of the cancelation of the Higgs mass quadratic divergence and would verify the little Higgs mechanism.Comment: 21 pages, 15 Postscript figure

Automated flight test management system

The Phase 1 development of an automated flight test management system (ATMS) as a component of a rapid prototyping flight research facility for artificial intelligence (AI) based flight concepts is discussed. The ATMS provides a flight engineer with a set of tools that assist in flight test planning, monitoring, and simulation. The system is also capable of controlling an aircraft during flight test by performing closed loop guidance functions, range management, and maneuver-quality monitoring. The ATMS is being used as a prototypical system to develop a flight research facility for AI based flight systems concepts at NASA Ames Dryden

Parental Divorce, Attachment, and Self-Other Conceptualization

The formation of strong attachment bonds in childhood and adolescence has a significant effect on adult self and other concepts operationalized here as self-esteem and hostility. These self-other conceptualizations are posited to facilitate the formation of successful relationships and well-being in adulthood. To determine whether parental separations before the age of 16 years disrupt attachment bonds and subsequent self-other conceptualizations, participants from three naturally formed parental marital status groups were compared on attachment, self-esteem and hostility: divorced parents (N = 622), married parents (N = 7, 424), or divorced but remarried parents (N = 313). Individuals who had divorced or remarried parents had significantly more insecure parental attachment bonds than those with married parents after controlling for demographics, childhood SES, and parental conflict. Parent marital status did not significantly predict self-esteem or hostility. However, secure attachment did predict higher self-esteem and lower hostility in all groups. Supplementary analyses showed that parental divorce paired with high levels of parental conflict predicted more insecure attachment bond