Experimental results for nulling the effective thermal expansion coefficient of fused silica fibres under a static stress

We have experimentally demonstrated that the effective thermal expansion coefficient of a fused silica fibre can be nulled by placing the fibre under a particular level of stress. Our technique involves heating the fibre and measuring how the fibre length changes with temperature as the stress on the fibre was systematically varied. This nulling of the effective thermal expansion coefficient should allow for the complete elimination of thermoelastic noise and is essential for allowing second generation gravitational wave detectors to reach their target sensitivity. To our knowledge this is the first time that the cancelation of the thermal expansion coefficient with stress has been experimentally observed

Strong Decays of Strange Quarkonia

In this paper we evaluate strong decay amplitudes and partial widths of strange mesons (strangeonia and kaonia) in the 3P0 decay model. We give numerical results for all energetically allowed open-flavor two-body decay modes of all nsbar and ssbar strange mesons in the 1S, 2S, 3S, 1P, 2P, 1D and 1F multiplets, comprising strong decays of a total of 43 resonances into 525 two-body modes, with 891 numerically evaluated amplitudes. This set of resonances includes all strange qqbar states with allowed strong decays expected in the quark model up to ca. 2.2 GeV. We use standard nonrelativistic quark model SHO wavefunctions to evaluate these amplitudes, and quote numerical results for all amplitudes present in each decay mode. We also discuss the status of the associated experimental candidates, and note which states and decay modes would be especially interesting for future experimental study at hadronic, e+e- and photoproduction facilities. These results should also be useful in distinguishing conventional quark model mesons from exotica such as glueballs and hybrids through their strong decays.Comment: 69 pages, 5 figures, 39 table

Small optic suspensions for Advanced LIGO input optics and other precision optical experiments

We report on the design and performance of small optic suspensions developed to suppress seismic motion of out-of-cavity optics in the Input Optics subsystem of the Advanced LIGO interferometric gravitational wave detector. These compact single stage suspensions provide isolation in all six degrees of freedom of the optic, local sensing and actuation in three of them, and passive damping for the other three

Shadowing in the nuclear photoabsorption above the resonance region

A model based on the hadronic fluctuations of the real photon is developed to describe the total photonucleon and photonuclear cross sections in the energy region above the nucleon resonances. The hadronic spectral function of the photon is derived including the finite width of vector-meson resonances and the quark-antiquark continuum. The shadowing effect is evaluated considering the effective interaction of the hadronic component with the bound nucleons within a Glauber-Gribov multiple scattering theory. The low energy onset of the shadowing effect is interpreted as a possible signature of a modification of the hadronic spectral function in the nuclear medium. A decrease of the $\rho$-meson mass in nuclei is suggested for a better explanation of the experimental data.Comment: 8 pages, 7 figure

Resonant Two-body D Decays

The contribution of a $K^*(1430)$ $0^+$ resonance to $D^0\to K^-\pi^+$ is calculated by applying the soft pion theorem to $D^+ \to K^* \pi^+$, and is found to be about 30% of the measured amplitude and to be larger than the $\Delta I=3/2$ component of this amplitude. We estimate a 70% contribution to the total amplitude from a higher $K^*(1950)$ resonance. This implies large deviations from factorization in D decay amplitudes, a lifetime difference between D^0 and D^+, and an enhancement of $D^0-\bar D^0$ mixing due to SU(3) breaking.Comment: To be published in Physical Review Letters, some corrections, references update

The Electromagnetic Mass Differences of Pions and Kaons

We use the Cottingham method to calculate the pion and kaon electromagnetic mass differences with as few model dependent inputs as possible. The constraints of chiral symmetry at low energy, QCD at high energy and experimental data in between are used in the dispersion relation. We find excellent agreement with experiment for the pion mass difference. The kaon mass difference exhibits a strong violation of the lowest order prediction of Dashen's theorem, in qualitative agreement with several other recent calculations.Comment: 40 pages, Latex, needs axodraw. and psfig. macros, 4 figure

DNA Binding Polyamides and the Importance of DNA Recognition in their use as Gene-Specific and Antiviral Agents

There is a long history for the bioorganic and biomedical use of N-methyl-pyrrole-derived polyamides (PAs) that are higher homologs of natural products such as distamycin A and netropsin. This work has been pursued by many groups, with the Dervan and Sugiyama groups responsible for many breakthroughs. We have studied PAs since about 1999, partly in industry and partly in academia. Early in this program, we reported methods to control cellular uptake of polyamides in cancer cell lines and other cells likely to have multidrug resistance efflux pumps induced. We went on to discover antiviral polyamides active against HPV31, where SAR showed that a minimum binding size of about 10 bp of DNA was necessary for activity. Subsequently we discovered polyamides active against two additional high-risk HPVs, HPV16 and 18, a subset of which showed broad spectrum activity against HPV16, 18 and 31. Aspects of our results presented here are incompatible with reported DNA recognition rules. For example, molecules with the same cognate DNA recognition properties varied from active to inactive against HPVs. We have since pursued the mechanism of action of antiviral polyamides, and polyamides in general, with collaborators at NanoVir, the University of Missouri-St. Louis, and Georgia State University. We describe dramatic consequences of β-alanine positioning even in relatively small, 8-ring polyamides; these results contrast sharply with prior reports. This paper was originally presented by JKB as a Keynote Lecture in the 2nd International Conference on Medicinal Chemistry and Computer Aided Drug Design Conference in Las Vegas, NV, October 2013

Individual differences in infant oculomotor behavior during the viewing of complex naturalistic scenes

Little research hitherto has examined how individual differences in attention, as assessed using standard experimental paradigms, relate to individual differences in how attention is spontaneously allocated in more naturalistic contexts. Here, we analyzed the time intervals between refoveating eye movements (fixation durations) while typically developing 11-month-old infants viewed a 90-min battery ranging from complex dynamic to noncomplex static materials. The same infants also completed experimental assessments of cognitive control, psychomotor reaction times (RT), processing speed (indexed via peak look during habituation), and arousal (indexed via tonic pupil size). High test–retest reliability was found for fixation duration, across testing sessions and across types of viewing material. Increased cognitive control and increased arousal were associated with reduced variability in fixation duration. For fixations to dynamic stimuli, in which a large proportion of saccades may be exogenously cued, we found that psychomotor RT measures were most predictive of mean fixation duration; for fixations to static stimuli, in contrast, in which there is less exogenous attentional capture, we found that psychomotor RT did not predict performance, but that measures of cognitive control and arousal did. The implications of these findings for understanding the development of attentional control in naturalistic settings are discussed

Hybrid Meson Decay Phenomenology

The phenomenology of a newly developed model of hybrid meson decay is developed. The decay mechanism is based on the heavy quark expansion of QCD and the strong coupling flux tube picture of nonperturbative glue. A comprehensive list of partial decay widths of a wide variety of light, $s\bar s$, $c\bar c$, and $b \bar b$ hybrid mesons is presented. Results which appear approximately universal are highlighted along with those which distinguish different hybrid decay models. Finally, we examine several interesting hybrid candidates in detail.Comment: 37 pages, 2 figures, 6 tables, Revte

The Wave Function of 2S Radially Excited Vector Mesons from Data for Diffraction Slope

In the color dipole gBFKL dynamics we predict a strikingly different Q^2 and energy dependence of the diffraction slope for the elastic production of ground state V(1S) and radially excited V'(2S) light vector mesons. The color dipole model predictions for the diffraction slope for \rho^0 and \phi^0 production are in a good agreement with the data from the fixed target and collider HERA experiments. We present how a different form of anomalous energy and Q^2 dependence of the diffraction slope for V'(2S) production leads to a different position of the node in radial wave function and discuss a possibility how to determine this position from the fixed target and HERA data.Comment: 20 pages and 6 figures. Title change