257 research outputs found

    Solid State Systems for Electron Electric Dipole Moment and other Fundamental Measurements

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    In 1968, F.L. Shapiro published the suggestion that one could search for an electron EDM by applying a strong electric field to a substance that has an unpaired electron spin; at low temperature, the EDM interaction would lead to a net sample magnetization that can be detected with a SQUID magnetometer. One experimental EDM search based on this technique was published, and for a number of reasons including high sample conductivity, high operating temperature, and limited SQUID technology, the result was not particularly sensitive compared to other experiments in the late 1970's. Advances in SQUID and conventional magnetometery had led us to reconsider this type of experiment, which can be extended to searches and tests other than EDMs (e.g., test of Lorentz invariance). In addition, the complementary measurement of an EDM-induced sample electric polarization due to application of a magnetic field to a paramagnetic sample might be effective using modern ultrasensitive charge measurement techniques. A possible paramagnetic material is Gd-substituted YIG which has very low conductivity and a net enhancement (atomic enhancement times crystal screening) of order unity. Use of a reasonable volume (100's of cc) sample of this material at 50 mK and 10 kV/cm might yield an electron EDM sensitivity of 103310^{-33} e cm or better, a factor of 10610^6 improvement over current experimental limits.Comment: 6 pages. Prepared for ITAMP workshop on fundamental physics that was to be held Sept 20-22 2001 in Cambride, MA, but was canceled due to terrorist attack on U.S New version incorporates a number of small changes, most notably the scaling of the sensitivity of the Faraday magnetometer with linewidth is now treated in a saner fashion. The possibility of operating at an even lower temperarture, say 10 microkelvin, is also discusse

    Characterization of Polyphosphoesters by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

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    FT-ICR mass spectrometry, together with collision-induced dissociation and electron capture dissociation, has been used to characterize the polyphosphoester poly[1,4-bis(hydroxyethyl)terephthalate-alt-ethyloxyphosphate] and its degradation products. Three degradation pathways were elucidated: hydrolysis of the phosphate–[1,4-bis(hydroxyethyl)terephthalate]bonds; hydrolysis of the phosphate–ethoxy bonds; and hydrolysis of the ethyl–terephthalate bonds. The dominant degradation reactions were those that involved the phosphate groups. This work constitutes the first application of mass spectrometry to the characterization of polyphosphoesters and demonstrates the suitability of high mass accuracy FT-ICR mass spectrometry, with CID and ECD, for the structural analysis of polyphosphoesters and their degradation products

    Effects of precompetition state anxiety interventions on performance time and accuracy among amateur soccer players: Revisiting the matching hypothesis

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    In this study, we tested the matching ypothesis, which contends that administration of a cognitive or somatic anxiety intervention should be matched to a participant's dominant anxiety response. Sixty-one male soccer players (mean age 31.6 years, s=6.3) were assigned to one of four groups based on their responses to the Competitive State Anxiety Inventory-2, which was modified to include a directional scale. Interventions were randomly administered in a counterbalanced order 10 min before each performance trial on a soccer skill test. The dominantly cognitive anxious group (n=17), the dominantly somatic anxious group (n=17), and the non-anxious control intervention group (n=14) completed a baseline performance trial. The second and third trials were completed with random administration of brief cognitive and somatic interventions. The non-anxious control group (n=13) completed three trials with no intervention. A mixed-model, GroupTreatment multivariate analysis of variance indicated significant (P0.05), or performance time or accuracy (P>0.05). The present findings do not provide support for the matching hypothesis for state anxiety intensity and direction, or for performance

    Predicting swimming performance using state anxiety

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    Competitive state anxiety is a common response to stressful competitive sports situations that could affect athletic performance. The effects of state anxiety on swimming performance need further inquiry. The aim of the study was to determine the component of state anxiety that best predicts swimming performance. A quantitative, cross-sectional study design that made use of the Competitive State Anxiety Inventory-2 to measure precompetitive state anxiety was used. A total of 61 male high school swimmers whose age ranged between 14 and 19 years (M = 16.16, standard deviation = 1.66 years) completed the Competitive State Anxiety Inventory-2 1 hr before competing in a 50-m individual swimming event. Performance was evaluated using finishing position. Due to the relatively short duration of the 50-m event, the available literature would suggest that Somatic Anxiety would have a greater effect on Performance - there is not enough time to allow cognitive anxiety to have a detrimental impact on performance. Thus, it was hypothesized that somatic rather than cognitive anxiety will best predict swimming performance. It emerged that both cognitive (b =.787; p <.001) and somatic anxieties (b =.840; p <.001) can independently predict swimming performance. However, when both cognitive and somatic anxieties were regressed onto swimming performance, somatic anxiety partially dominated cognitive anxiety (b =.626; p <.001) and became the significant predictor of swimming performance. It is recommended that swimmers and swimming coaches make use of specific intervention strategies that eradicate the detrimental effects of somatic anxiety immediately before competition.IS

    Modified Thomson spectrometer design for high energy, multi-species ion sources

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    A modification to the standard Thomson parabola spectrometer is discussed, which is designed to measure high energy (tens of MeV/nucleon), broad bandwidth spectra of multi-species ions accelerated by intense laser plasma interactions. It is proposed to implement a pair of extended, trapezoidal shaped electric plates, which will not only resolve ion traces at high energies, but will also retain the lower energy part of the spectrum. While a longer (along the axis of the undeflected ion beam direction) electric plate design provides effective charge state separation at the high energy end of the spectrum, the proposed new trapezoidal shape will enable the low energy ions to reach the detector, which would have been clipped or blocked by simply extending the rectangular plates to enhance the electrostatic deflection

    Is the 6 kDa tobacco etch viral protein a bona fide ERES marker?

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    The claim that the 6 kDa viral protein (VP) of Tobacco Etch Virus is a marker for ER exit sites (ERES) has been investigated. When transiently expressed as a CFP tagged fusion construct in tobacco mesophyll protoplasts, this integral membrane protein co-localizes with both the COPII coat protein YFP-SEC24 and the Golgi marker Man1-RFP. However, when over-expressed the VP locates to larger spherical structures which co-localize with neither ER nor Golgi markers. Nevertheless, deletion of the COPII interactive N-terminal D(X)E motif causes it to be broadly distributed throughout the ER, supporting the notion that this protein could be an ERES marker. Curiously, whereas brefeldin A (BFA) caused a typical Golgi-stack response (redistribution into the ER) of the VP in leaf epidermal cells, in protoplasts it resulted in the formation of structures identical to those formed by over-expression. However, anomalous results were obtained with protoplasts: when co-expressed with the non-cycling cis-Golgi marker Man1-RFP, a BFA-induced redistribution of the VP-CFP signal into the ER was observed, but, in the presence of the cycling Golgi marker ERD2-YFP, this did not occur. High resolution images of side-on views of Golgi stacks in epidermal cells showed that the 6 kDa VP-CFP signal overlapped considerably more with YFP-SEC24 than with Man1-RFP, indicating that the VP is proportionately more associated with ERES. However, based on a consideration of the structure of its cytoplasmic tail, the scenario that the VP collects at ERES and is transported to the cis-Golgi before being recycled back to the ER, is supported
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