699 research outputs found

    Analysis of Transit Fare Evasion in the Rose Quarter

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    Tri-Met collected fare evasion data for buses and MAX trains passing outbound through the Rose Quarter Monday, June 11 through Saturday, July 7. Beginning September 2001, Tri-Met’s “Fareless Square’s” free zone was extended towards the Lloyd District, with an eastern boundary of NE 14th. Prior to this, all trips between the Central Business District and Lloyd Center required a full Zone 1 fare

    Using Big Bang Nucleosynthesis to Extend CMB Probes of Neutrino Physics

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    We present calculations showing that upcoming Cosmic Microwave Background (CMB) experiments will have the power to improve on current constraints on neutrino masses and provide new limits on neutrino degeneracy parameters. The latter could surpass those derived from Big Bang Nucleosynthesis (BBN) and the observationally-inferred primordial helium abundance. These conclusions derive from our Monte Carlo Markov Chain (MCMC) simulations which incorporate a full BBN nuclear reaction network. This provides a self-consistent treatment of the helium abundance, the baryon number, the three individual neutrino degeneracy parameters and other cosmological parameters. Our analysis focuses on the effects of gravitational lensing on CMB constraints on neutrino rest mass and degeneracy parameter. We find for the PLANCK experiment that total (summed) neutrino mass Mν>0.29M_{\nu} > 0.29 eV could be ruled out at 2σ2\sigma or better. Likewise neutrino degeneracy parameters ξνe>0.11\xi_{\nu_{e}} > 0.11 and ξνμ/τ>0.49| \xi_{\nu_{\mu/\tau}} | > 0.49 could be detected or ruled out at 2σ2\sigma confidence, or better. For POLARBEAR we find that the corresponding detectable values are Mν>0.75eVM_\nu > 0.75 {\rm eV}, ξνe>0.62\xi_{\nu_{e}} > 0.62, and ξνμ/τ>1.1| \xi_{\nu_{\mu/\tau}}| > 1.1, while for EPIC we obtain Mν>0.20eVM_\nu > 0.20 {\rm eV}, ξνe>0.045\xi_{\nu_{e}} > 0.045, and ξνμ/τ>0.29|\xi_{\nu_{\mu/\tau}}| > 0.29. Our forcast for EPIC demonstrates that CMB observations have the potential to set constraints on neutrino degeneracy parameters which are better than BBN-derived limits and an order of magnitude better than current WMAP-derived limits.Comment: 27 pages, 11 figures, matches published version in JCA

    CMB Beam Systematics: Impact on Lensing Parameter Estimation

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    The CMB's B-mode polarization provides a handle on several cosmological parameters most notably the tensor-to-scalar ratio, rr, and is sensitive to parameters which govern the growth of large scale structure (LSS) and evolution of the gravitational potential. The primordial gravitational-wave- and secondary lensing-induced B-mode signals are very weak and therefore prone to various foregrounds and systematics. In this work we use Fisher-matrix-based estimations and apply, for the first time, Monte-Carlo Markov Chain (MCMC) simulations to determine the effect of beam systematics on the inferred cosmological parameters from five upcoming experiments: PLANCK, POLARBEAR, SPIDER, QUIET+CLOVER and CMBPOL. We consider beam systematics which couple the beam substructure to the gradient of temperature anisotropy and polarization (differential beamwidth, pointing and ellipticity) and beam systematics due to differential beam normalization (differential gain) and orientation (beam rotation) of the polarization-sensitive axes (the latter two effects are insensitive to the beam substructure). We determine allowable levels of beam systematics for given tolerances on the induced parameter errors and check for possible biases in the inferred parameters concomitant with potential increases in the statistical uncertainty. All our results are scaled to the 'worst case scenario'. In this case and for our tolerance levels, the beam rotation should not exceed the few-degree to sub-degree level, typical ellipticity is required to be 1% level, the differential gain allowed level is a few parts in 10310^{3} to 10410^{4}, differential beamwidth upper limits are of the sub-percent level and differential pointing should not exceed the few- to sub-arcsec level.Comment: 19 pages, 4 figures, 13 tables. Version matches published versio

    CMB Polarization Systematics Due to Beam Asymmetry: Impact on Cosmological Birefringence

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    The standard cosmological model is assumed to respect parity symmetry. Under this assumption the cross-correlations of the CMB's temperature anisotropy and `gradient'-like polarization, with the `curl'-like polarization identically vanish over the full sky. However, extensions of the standard model which allow for light scalar field or axion coupling to the electromagnetic field, or coupling to the Riemann gravitational field-strength, as well as other modifications of field theories, may induce a rotation of the CMB polarization plane on cosmological scales and manifest itself as nonvanishing TB and EB cross-correlations. Recently, the degree of parity violation (reflected in polarization rotation) was constrained using data from BOOMERANG, WMAP and QUAD. Forecasts have been made for near-future experiments (e.g. PLANCK) to further constrain parity- and Lorentz-violating terms in the fundamental interactions of nature. Here we consider a real-world effect induced by a class of telescope beam systematics which can mimic the rotation of polarization plane or otherwise induce nonvanishing TB and EB correlations. In particular, adopting the viewpoint that the primary target of future experiments will be the inflationary B-mode signal, we assume the beam-systematics of the upcoming PLANCK and POLARBEAR experiments are optimized towards this goal, and explore the implications of the allowed levels of beam systematics on the resulting precision of polarization-rotation measurements.Comment: 9 pages. Minor typos corrected. Matches published version in PRD Vol. 79 No. 1

    The Effects of Game Size on the Physical Activity Levels and Ball Touches of Elementary School Children in Physical Education

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    The purpose of this study was to determine the impact of participating in small (3v3), medium (6v6), and large-sided (12v12) games on the physical activity levels (pedometer step counts, accelerometer counts, and minutes of moderate-to-vigorous physical activity) and ball touches of children in physical education class. Participants were 29 students (55% boys and 45% girls) age 10-11 yrs. All participants wore a Yamax SW-200 pedometer and had their ball touches monitored and recorded. Twelve participants also wore an ActiGraph GT3X accelerometer. Repeated measure ANOVAs were computed to test for significant differences for each dependant variable with corresponding post hoc tests. Results indicated the 3v3 and 6v6 game conditions yielded significantly higher accelerometer counts and ball touches than the 12v12 condition. The 3v3 game condition also produced significantly higher ball touches than the 6v6 condition. These findings highlight the importance of utilizing smaller-sided games in physical education to promote increased involvement and physical activity

    Revealing Cosmic Rotation

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    Cosmological Birefringence (CB), a rotation of the polarization plane of radiation coming to us from distant astrophysical sources, may reveal parity violation in either the electromagnetic or gravitational sectors of the fundamental interactions in nature. Until only recently this phenomenon could be probed with only radio observations or observations at UV wavelengths. Recently, there is a substantial effort to constrain such non-standard models using observations of the rotation of the polarization plane of cosmic microwave background (CMB) radiation. This can be done via measurements of the BB-modes of the CMB or by measuring its TB and EB correlations which vanish in the standard model. In this paper we show that EBEB correlations-based estimator is the best for upcoming polarization experiments. The EBEB based estimator surpasses other estimators because it has the smallest noise and of all the estimators is least affected by systematics. Current polarimeters are optimized for the detection of BB-mode polarization from either primordial gravitational waves or by large scale structure via gravitational lensing. In the paper we also study optimization of CMB experiments for the detection of cosmological birefringence, in the presence of instrumental systematics, which by themselves are capable of producing EBEB correlations; potentially mimicking CB.Comment: 10 pages, 3 figures, 2 table

    CMB Temperature Polarization Correlation and Primordial Gravitational Waves

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    We examine the use of the CMB's TE cross correlation power spectrum as a complementary test to detect primordial gravitational waves (PGWs). The first method used is based on the determination of the lowest multipole, 0\ell_0, where the TE power spectrum, CTEC_{\ell}^{TE}, first changes sign. The second method uses Wiener filtering on the CMB TE data to remove the density perturbations contribution to the TE power spectrum. In principle this leaves only the contribution of PGWs. We examine two toy experiments (one ideal and another more realistic) to see their ability to constrain PGWs using the TE power spectrum alone. We found that an ideal experiment, one limited only by cosmic variance, can detect PGWs with a ratio of tensor to scalar metric perturbation power spectra r=0.3r=0.3 at 99.9% confidence level using only the TE correlation. This value is comparable with current constraints obtained by WMAP based on the 2σ2\sigma upper limits to the B-mode amplitude. We demonstrate that to measure PGWs by their contribution to the TE cross correlation power spectrum in a realistic ground based experiment when real instrumental noise is taken into account, the tensor-to-scalar ratio, rr, should be approximately three times larger.Comment: 13 pages, 13 figures, version matches published version. Combined with 0710.365
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