Measurement of the W-boson helicity fractions in top-quark decays at CDF

We present a measurement of the fractions F_0 and F_+ of longitudinally polarized and right-handed W bosons in top-quark decays using data collected with the CDF II detector. The data set used in the analysis corresponds to an integrated luminosity of approximately 955 pb-1. We select top-antitop candidate events with one lepton, at least four jets, and missing transverse energy. Our helicity measurement uses the decay angle theta*, which is defined as the angle between the momentum of the charged lepton in the W boson rest-frame and the W momentum in the top-quark rest-frame. The cos(theta*) distribution in the data is determined by full kinematic reconstruction of the top-antotop candidates. We find F_0 = 0.59 +- 0.12 (stat) +0.07 -0.06 (syst) and F_+ = -0.03 +- 0.06 (stat) +0.04 -0.03 (syst), which is consistent with the standard model prediction. We set an upper limit on the fraction of right-handed W-bosons of F_+ < 0.1 at the 95% confidence level.Comment: For the Proceedings of the 42nd Rencontres de Moriond 2007, Electroweak Interactions and Unified Theorie

Examining the "No-Choice" Option in Choice-Based Conjoint Analysis

Choice-Based Conjoint analysis (CBC) is a method used to determine how individual consumers value attributes of a product or service. The consumer selects the option he or she would be most likely to purchase among those presented, which includes a "no-choice" option. The "no-choice" option is an alternative within a CBC analysis that allows consumers to decide against purchasing any of the presented options. This no-choice option is necessary in order to correctly simulate real choices, but could be problematic if each consumer perceives this option differently (Allenby, et. al. 1995). The goal of this research is to provide a recommendation for how to improve the consistency of choices in CBC analysis. We employ the framework in General Evaluability Theory (Hsee & Zhang 2010) to justify potential improvements to CBC. We hypothesize that evaluability of the no-choice option can be improved by creating a consistent view of the frontier of products available to the consumer. We will test this hypothesis by sampling 1000 respondents randomly split into three different groups, with each group receiving a different amount of information about the products in the market. A control group will engage in standard CBC, the first treatment group will be shown the prices of products in the market, and a second treatment group will be shown the price of products in relation to multiple attributes of the product. The results show no significant differences in the propensity to select the no-choice option between the three experimental groups. Fitting a Hierarchical Multinomial Logit Model to the data, three attributes show significant differences in the upper level between the control group and treatment group one. This suggests that participants in the treatment group value products with those attributes more highly compared to participants in the control group. Further investigation looked at qualified versus non-qualified survey participants and showed that additional information about the market gave non-qualified participants a lower propensity to select the no-choice option. We conclude that using proper screening techniques allows standard Choice-Based Conjoint Analysis to be a robust tool for marketing researchers given the results from qualified survey respondents.No embargoAcademic Major: Financ

Liquid-gas flow in venturi meter and sharp edged orifice

The results of a study of pressure drops across a 5/32 inch throat venturi meter and a 5/32 inch thin plate sharp-edged orifice for the horizontal cocurrent, flow of the air-water two-phase two-fluid system in a 3/4 inch pipe under essentially isothermal conditions, are presented. This is the first critical study of two phase flow in a Venturi meter and. in a 5/32 orifice. Flows of water of 0.1 to 1.7 gallons per minute with air rates in range of 0.00022 lbs/sec. to 0.0092 lbs/sec. of air mixed in were studied. All flows were turbulent when judged with the conventional Reynolds number criteria. It was found that two phase two fluid flaw in this region was not steady but fluctuated. Predicted pressure drops calculated with the Chenoweth-Martin Correlation (1) gave results which were 50% to 150 too high for the orifice. An improved correlation is presented which gives predicted pressure drops to within 15% of the actual results for 85% of the data calculated, for both the orifice and the Venturi. It is shown that temperature has important influence on single phase water flow in venturi, a 3.0% increase in pressure drop being observed with temperature rise in tap water trims 3.0°C to 40°C

Top Quark Asymmetries

The production of top quark pairs (t$\overline{t}$) via the quark-antiquark initial state is not symmetric under the exchange of top quark and antiquark. Calculations of this next-to-leading order effect predict asymmetries of about one to a few percent, depending on the centre-of-mass energy and the selected phase space. Experimentally, this charge asymmetry of t$\overline{t}$ production manifests itself in differences in angular distributions between top quarks and antiquarks. Sensitive observables are the rapidities of the produced top quarks and antiquarks as well as their energies. In dileptonic t$\overline{t}$ events, the asymmetry of the t$\overline{t}$ system is reflected in a similar asymmetry in the system of the produced lepton pair, with the crucial advantage of a simpler reconstruction procedure. In this article we review the measurements of this effect in different final states and using different observables by the ATLAS and CMS Collaborations in LHC collisions at three different centre-of-mass energies

The Use of Dialectical Behavior Therapy (DBT) in Music Therapy: A Survey of Current Practice

This study used a mixed methods design to survey the current use of DBT in music therapy practice in mental health settings. Respondents (N = 48) were members of the American Music Therapy Association who indicated working in mental health settings. Respondents reported their use of DBT in their music therapy practice. Results were gathered using an Internet based survey. The results indicated that respondents desired more DBT training, as their self-reported competency in implementing DBT in music therapy was low, while their perceived importance of implementing DBT in music therapy was high. Results also indicated that music therapists are implementing components of DBT rather than the standard DBT protocol. Two music therapists with experience implementing DBT in music therapy shared their expertise through interviews. The interviewees identified ways music therapy can enhance DBT, which included: providing an experiential therapy where clients can practice skills that can be generalized; providing an opportunity to nonverbally experience and express emotions; and using music to access the body, mind, and soul of a person. This study indicated the need for future research exploring the use of DBT in music therapy

Comparison of s- and d-wave gap symmetry in nonequilibrium superconductivity

Recent application of ultrafast pump/probe optical techniques to superconductors has renewed interest in nonequilibrium superconductivity and the predictions that would be available for novel superconductors, such as the high-Tc cuprates. We have reexamined two of the classical models which have been used in the past to interpret nonequilibrium experiments with some success: the mu* model of Owen and Scalapino and the T* model of Parker. Predictions depend on pairing symmetry. For instance, the gap suppression due to excess quasiparticle density n in the mu* model, varies as n^{3/2} in d-wave as opposed to n for s-wave. Finally, we consider these models in the context of S-I-N tunneling and optical excitation experiments. While we confirm that recent pump/probe experiments in YBCO, as presently interpreted, are in conflict with d-wave pairing, we refute the further claim that they agree with s-wave.Comment: 14 pages, 11 figure

Subpicosecond time‐resolved studies of coherent phonon oscillations in thin‐film YBa2Cu3O6+x (x<0.4)

We report the results of the first time‐resolved observation of impulsively generated coherent optical phonon oscillations in the semiconducting cuprate compound YBa2Cu3O6+x (x<0.4). The oscillations, which were probed through time‐resolved transmissivity modulation, had a period of 237 fs at room temperature, corresponding to a Raman active mode of A1g symmetry at 142 cm−1. No oscillations were observed in the superconducting form of Y‐Ba‐Cu‐O either above or below Tc. The amplitude, frequency, and linewidth of this mode were measured over a temperature range from ∼7 K to room temperature.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70769/2/APPLAB-58-9-980-1.pd

Expandable and Rapidly Differentiating Human Induced Neural Stem Cell Lines for Multiple Tissue Engineering Applications

Limited availability of human neurons poses a significant barrier to progress in biological and preclinical studies of the human nervous system. Current stem cell-based approaches of neuron generation are still hindered by prolonged culture requirements, protocol complexity, and variability in neuronal differentiation. Here we establish stable human induced neural stem cell (hiNSC) lines through the direct reprogramming of neonatal fibroblasts and adult adipose-derived stem cells. These hiNSCs can be passaged indefinitely and cryopreserved as colonies. Independently of media composition, hiNSCs robustly differentiate into TUJ1-positive neurons within 4 days, making them ideal for innervated co-cultures. In vivo, hiNSCs migrate, engraft, and contribute to both central and peripheral nervous systems. Lastly, we demonstrate utility of hiNSCs in a 3D human brain model. This method provides a valuable interdisciplinary tool that could be used to develop drug screening applications as well as patient-specific disease models related to disorders of innervation and the brain