Northern Illinois University

About: Northern Illinois University is a education organization based out in DeKalb, Illinois, United States. It is known for research contribution in the topics: Large Hadron Collider & Population. The organization has 8818 authors who have published 20008 publications receiving 632341 citations. The organization is also known as: NIU.

Highly selective electrocatalytic CO2 reduction to ethanol by metallic clusters dynamically formed from atomically dispersed copper

Abstract: Direct electrochemical conversion of CO2 to ethanol offers a promising strategy to lower CO2 emissions while storing energy from renewable electricity. However, current electrocatalysts offer only limited selectivity toward ethanol. Here we report a carbon-supported copper (Cu) catalyst, synthesized by an amalgamated Cu–Li method, that achieves a single-product Faradaic efficiency (FE) of 91% at −0.7 V (versus the reversible hydrogen electrode) and onset potential as low as −0.4 V (reversible hydrogen electrode) for electrocatalytic CO2-to-ethanol conversion. The catalyst operated stably over 16 h. The FE of ethanol was highly sensitive to the initial dispersion of Cu atoms and decreased significantly when CuO and large Cu clusters become predominant species. Operando X-ray absorption spectroscopy identified a reversible transformation from atomically dispersed Cu atoms to Cun clusters (n = 3 and 4) on application of electrochemical conditions. First-principles calculations further elucidate the possible catalytic mechanism of CO2 reduction over Cun. Electrocatalytically reducing CO2 to ethanol can provide renewably generated fuel, but catalysts are often poorly selective for this conversion. Here the authors use a Cu catalyst to produce ethanol with high selectivity. Cu dispersion is key to the performance and operando studies indicate that it changes under reaction conditions.

Muon Anomalous Magnetic Dipole Moment in Supersymmetric Theories

Abstract: We study the muon anomalous magnetic dipole moment in supersymmetric theories. The impact of the recent Brookhaven E821 experimental measurement on both model-independent and model-dependent supersymmetric parameter spaces is discussed in detail. We find that values of $\mathrm{tan}\ensuremath{\beta}$ as low as 3 can be obtained while remaining within the E821 one-sigma bound. This requires a light smuon; however, we show that, somewhat surprisingly, no model-independent bound can be placed on the mass of the lightest chargino for any $\mathrm{tan}\ensuremath{\beta}g~3.$ We also show that the maximum contributions to the anomalous magnetic moment are insensitive to CP-violating phases. We provide analyses of the supersymmetric contribution to the muon anomalous magnetic moment in dilaton-dominated supergravity models and gauge-mediated supersymmetry-breaking models. Finally, we discuss how other phenomena, such as $B(\stackrel{\ensuremath{\rightarrow}}{b}s\ensuremath{\gamma}),$ relic abundance of the lightest superpartner, and the Higgs boson mass may be correlated with the anomalous magnetic moment, but do not significantly impact the viability of a supersymmetric explanation, or the mass limits obtainable on smuons and charginos.

Forward-backward asymmetry in top quark-antiquark production

Abstract: We present a measurement of forward-backward asymmetry in top quark-antiquark production in proton-antiproton collisions in the final state containing a lepton and at least four jets. Using a dataset corresponding to an integrated luminosity of $5.4\,\mathrm {fb}^{-1}$, collected by the \DZ\ experiment at the Fermilab Tevatron Collider, we measure the \ttbar\ forward-backward asymmetry to be $(9.2 \pm 3.7)$% at the reconstruction level. When corrected for detector acceptance and resolution, the asymmetry is found to be $(19.6 \pm 6.5)$%. We also measure a corrected asymmetry based on the lepton from a top quark decay, found to be $(15.2 \pm 4.0)$%. The results are compared to predictions based on the next-to-leading-order QCD generator {\sc mc@nlo}. The sensitivity of the measured and predicted asymmetries to the modeling of gluon radiation is discussed.

Physics Beyond Colliders at CERN: Beyond the Standard Model Working Group Report

Abstract: The Physics Beyond Colliders initiative is an exploratory study aimed at exploiting the full scientific potential of the CERN's accelerator complex and scientific infrastructures through projects complementary to the LHC and other possible future colliders. These projects will target fundamental physics questions in modern particle physics. This document presents the status of the proposals presented in the framework of the Beyond Standard Model physics working group, and explore their physics reach and the impact that CERN could have in the next 10-20 years on the international landscape.

Gendered motivational processes affecting high school mathematics participation, educational aspirations, and career plans: a comparison of samples from Australia, Canada, and the United States.

Abstract: In this international, longitudinal study, we explored gender differences in, and gendered relationships among, math-related motivations emphasized in the Eccles (Parsons) et al. (1983) expectancy-value framework, high school math participation, educational aspirations, and career plans. Participants were from Australia, Canada, and the United States (Ns 358, 471, 418, respectively) in Grades 9/10 at Time 1 and Grades 11/12 at Time 2. The 3 samples came from suburban middle to upper-middle socioeconomic backgrounds, primarily of Anglo-European descent. Multivariate analyses of variance revealed stereotypic gender differences in educational and occupational outcomes only among the Australian sample. Multigroup structural equation models identified latent mean differences where male adolescents held higher intrinsic value for math in the Australian sample and higher ability/success expectancy in both North American samples. Ability/success expectancy was a key predictor in the North American samples, in contrast to intrinsic value in the Australian sample. Attainment/utility (“importance”) values were more important for female adolescents’ career choices, except in the Australian sample. Findings are interpreted in relation to gender socialization practices, degree and type of early choice, and specialization across settings. Implications are discussed for long-term math engagement and career selection for female and male adolescents.