2,493 research outputs found

    Studying patterns of use of transport modes through data mining - Application to U.S. national household travel survey data set

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    Data collection activities related to travel require large amounts of financial and human resources to be conducted successfully. When available resources are scarce, the information hidden in these data sets needs to be exploited, both to increase their added value and to gain support among decision makers not to discontinue such efforts. This study assessed the use of a data mining technique, association analysis, to understand better the patterns of mode use from the 2009 U.S. National Household Travel Survey. Only variables related to self-reported levels of use of the different transportation means are considered, along with those useful to the socioeconomic characterization of the respondents. Association rules potentially showed a substitution effect between cars and public transportation, in economic terms but such an effect was not observed between public transportation and nonmotorized modes (e.g., bicycling and walking). This effect was a policy-relevant finding, because transit marketing should be targeted to car drivers rather than to bikers or walkers for real improvement in the environmental performance of any transportation system. Given the competitive advantage of private modes extensively discussed in the literature, modal diversion from car to transit is seldom observed in practice. However, after such a factor was controlled, the results suggest that modal diversion should mainly occur from cars to transit rather than from nonmotorized modes to transi

    Light dark forces at flavor factories

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    SuperB experiment could represent an ideal environment to test a new U (1) symmetry related to light dark forces candidates. A promising discovery channel is represented by the resonant production of a boson U, followed by its decay into lepton pairs. Beyond approximations adopted in the literature, an exact tree level calculation of the radiative processes e+e−→γ,U→Ό+ÎŒâˆ’Îł,e+e−γe+ e- \rightarrow \gamma, U \rightarrow \mu^+ \mu^- \gamma, e^+ e^- \gamma and corresponding QED backgrounds is performed, including also the most important higher-order corrections. The calculation is implemented in a release of the generator BabaYaga@NLO useful for data analysis and interpretation. The distinct features of U boson production are shown and the statistical significance is analysed

    On the Lack of Correlation Between [OIII]/[OII] and Lyman-Continuum Escape Fraction

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    We present the first results of our pilot study of 8 photometrically selected Lyman continuum (LyC) emitting galaxy candidates from the COSMOS field and focus on their optical emission line ratios. Observations were performed in the H and K bands using the Multi-Object Spectrometer for Infra-Red Exploration (MOSFIRE) instrument at the Keck Observatory, targeting the [OII], HÎČ\beta, and [OIII] emission lines. We find that photometrically selected LyC emitting galaxy candidates have high ionization parameters, based on their high [OIII]/[OII] ratios (O32), with an average ratio for our sample of 2.5±\pm0.2. Preliminary results of our companion Low Resolution Imaging Spectrometer (LRIS) observations, targeting LyC and Lyα\alpha, show that those galaxies with the largest O32 are typically found to also be Lyα\alpha emitters. High O32 galaxies are also found to have tentative non-zero LyC escape fractions (fesc(LyC)f_{esc}(LyC)) based on uu band photometric detections. These results are consistent with samples of highly ionized galaxies, including confirmed LyC emitting galaxies from the literature. We also perform a detailed comparison between the observed emission line ratios and simulated line ratios from density bounded HII_{\textrm{II}} regions modeled using the photoionization code MAPPINGS V. Estimates of fesc(LyC)f_{esc}(LyC) for our sample fall in the range from 0.0-0.23 and suggest possible tension with published correlations between O32 and fesc(LyC)f_{esc}(LyC), adding weight to dichotomy of arguments in the literature. We highlight the possible effects of clumpy geometry and mergers that may account for such tension.Comment: 21 pages, 11 figures, 3 tables, accepted for publication in MNRA

    Evidence for CP Violation in B0 -> D+D- Decays

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    We report measurements of the branching fraction and CP violation parameters in B0 -> D+D- decays. The results are based on a data sample that contains 535 x 10^6 BBbar pairs collected at the Upsilon(4S) resonance, with the Belle detector at the KEKB asymmetric-energy e+e- collider. We obtain [1.97 +- 0.20 (stat) +- 0.20 (syst)] x 10^(-4) for the branching fraction of B0 -> D+D-. The measured values of the CP violation parameters are: S = -1.13 +- 0.37 +- 0.09, A = 0.91 +- 0.23 +- 0.06, where the first error is statistical and the second is systematic. We find evidence of CP violation in B0 -> D+D- at the 4.1 sigma confidence level. While the value of S is consistent with expectations from other measurements, the value of the parameter A favors large direct CP violation at the 3.2 sigma confidence level, in contradiction to Standard Model expectations.Comment: 12 pages, 3 figures, submitted to PR

    Study of B -> \rho \pi decays at Belle

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    This paper describes a study of B meson decays to the pseudoscalar-vector final state \rho\pi using 31.9\times 10^6 B\bar{B} events collected with the Belle detector at KEKB. The branching fractions B(B^+ \to \rho^0\pi^+) = (8.0^{+2.3+0.7}_{-2.0-0.7}) \times 10^{-6} and B(B^0 -> \rho^{+-} \pi^{-+}) = (20.8^{+6.0+2.8}_{-6.3-3.1}) \times 10^{-6} are obtained. In addition, a 90% confidence level upper limit of B(B^0 \to \rho^0\pi^0) < 5.3 \times 10^{-6}is reported.Comment: 14 pages, 3 figures, to be submitted to Phys. Lett.

    Study of the Baryon-Antibaryon Low-Mass Enhancements in Charmless Three-body Baryonic B Decays

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    The angular distributions of the baryon-antibaryon low-mass enhancements seen in the charmless three-body baryonic B decays B+ -> p pbar K+, B0 -> p pbar Ks, and B0 -> p Lambdabar pi- are reported. A quark fragmentation interpretation is supported, while the gluonic resonance picture is disfavored. Searches for the Theta+ and Theta++ pentaquarks in the relevant decay modes and possible glueball states G with 2.2 GeV/c2 < M-ppbar < 2.4 GeV/c2 in the ppbar systems give null results. We set upper limits on the products of branching fractions, B(B0 -> Theta+ p)\times B(Theta+ -> p Ks) Theta++ pbar) \times B(Theta++ -> p K+) G K+) \times B(G -> p pbar) < 4.1 \times 10^{-7} at the 90% confidence level. The analysis is based on a 140 fb^{-1} data sample recorded on the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider.Comment: 14 pages, 13 figure files, update of hep-ex/0409010 for journal submisssio

    Microbiome preterm birth DREAM challenge: Crowdsourcing machine learning approaches to advance preterm birth research

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    This research was carried out within the framework of the DREAM Community of Premature Births, of which UDC researchers Diego FernĂĄndez-Edreira and Carlos FernĂĄndez-Lozano, who have collaborated in the research, are members.Supplementary research data are available at https://www.cell.com/cms/10.1016/j.xcrm.2023.101350/attachment/e44bcada-f500-4f17-bc33-0ee5d39b3c4b/mmc1.pdf.[Abstract]: Every year, 11% of infants are born preterm with significant health consequences, with the vaginal microbiome a risk factor for preterm birth. We crowdsource models to predict (1) preterm birth (PTB; <37 weeks) or (2) early preterm birth (ePTB; <32 weeks) from 9 vaginal microbiome studies representing 3,578 samples from 1,268 pregnant individuals, aggregated from public raw data via phylogenetic harmonization. The predictive models are validated on two independent unpublished datasets representing 331 samples from 148 pregnant individuals. The top-performing models (among 148 and 121 submissions from 318 teams) achieve area under the receiver operator characteristic (AUROC) curve scores of 0.69 and 0.87 predicting PTB and ePTB, respectively. Alpha diversity, VALENCIA community state types, and composition are important features in the top-performing models, most of which are tree-based methods. This work is a model for translation of microbiome data into clinically relevant predictive models and to better understand preterm birth.We thank members of the Sirota Lab, University of California, San Francisco, for useful discussion. This study was supported by the March of Dimes (J.L.G., T.T.O., A.R., A.S.T., V.C., C.W.Y.H., R.J.W., K.J.F., G.A., I.K., J.B., A.N., J.G., Z.W., P.N., A.K., I.B., E.K., S.J., S.N., Y.S.L., P.R.B., D.A.M., S.V.L., J.A., D.K.S., N.Aghaeepour, J.C.C., M.S.) and R35GM138353 (N.Aghaeepour), 1R01HL139844 (N.Aghaeepour), 3P30AG066515 (N.Aghaeepour), 1R61NS114926 (N.Aghaeepour), 1R01AG058417 (N.Aghaeepour), R01HD105256 (N.Aghaeepour, M.S.), P01HD106414 (N.Aghaeepour), R01GM140464 (J.G., Z.W., G.C., Z.-Z.T.), NSF DMS-2054346 (J.G., Z.W., G.C., Z.-Z.T.); the Burroughs Welcome Fund (N.Aghaeepour); the Alfred E. Mann Foundation (N.Aghaeepour); and the Robertson Foundation (N.Aghaeepour). A.P.-L. and P.D.-G. are receiving honoraria from the IVI Foundation.United States. National Institute of General Medical Sciences; R35GM138353United States. National Institutes of Health; 1R01HL139844United States. National Institutes of Health; 3P30AG066515United States. National Institutes of Health; 1R61NS114926United States. National Institute on Aging; 1R01AG058417United States. National Institute of Child Health and Human Development; R01HD105256United States. National Institute of Child Health and Human Development; P01HD106414United States. National Institutes of Health; R01GM140464United States. National Science Foundation; DMS-205434

    An inclusive measurement of the photon energy spectrum in b->s gamma decays

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    We report a fully inclusive measurement of the flavour changing neutral current decay b->s gamma in the energy range 1.8 GeV < E* < 2.8 GeV, covering 95% of the total spectrum. Using 140 fb^-1 we obtain BF(b->s gamma)= 3.55 +/- 0.32 +0.30-0.31 +0.11-0.07, where the errors are statistical, systematic and from theory corrections. We also measure the first and second moments of the photon energy spectrum above 1.8 GeV and obtain = 2.292 +/- 0.026 +/- 0.034 GeV and -^2 = 0.0305 +/- 0.0074 +/- 0.0063 GeV^2, where the errors are statistical and systematic.Comment: RevTex4, 6 pages, Submitted to Phys.Rev.Lett. Replaced: added table of systematic errors. New results take into account radiative J/Psi decay

    Evidence of the Purely Leptonic Decay B- --> tau- nu_tau-bar

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    We present the first evidence of the decay B- --> tau- nu_tau-bar using 414 fb^-1 of data collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. Events are tagged by fully reconstructing one of the B mesons in hadronic modes. We detect the signal with a significance of 3.5 standard deviations including systematics, and measure the branching fraction to be Br(B- --> tau- nu_tau-bar) = (1.79 +0.56-0.49(stat) +0.46-0.51(syst))*10^-4. This implies that f_B = 0.229 +0.036-0.031(stat) +0.034-0.037(syst) GeV and is the first direct measurement of this quantity.Comment: 6 pages, 3 figures, to appear in Physical Review Letter
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