University of California, Davis

About: University of California, Davis is a education organization based out in Davis, California, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 78770 authors who have published 180033 publications receiving 8064158 citations. The organization is also known as: UC Davis & UCD.

Metal Oxide Surfaces and Their Interactions with Aqueous Solutions and Microbial Organisms.

Abstract: Reference LPI-ARTICLE-1999-017View record in Web of Science Record created on 2006-02-21, modified on 2017-05-12

Cosmic chronometers: constraining the equation of state of dark energy. I: H(z) measurements

Abstract: We present new determinations of the cosmic expansion history from red-envelope galaxies. We have obtained for this purpose high-quality spectra with the Keck-LRIS spectrograph of red-envelope galaxies in 24 galaxy clusters in the redshift range 0.2 < z < 1.0. We complement these Keck spectra with high-quality, publicly available archival spectra from the SPICES and VVDS surveys. We improve over our previous expansion history measurements in Simon et al. (2005) by providing two new determinations of the expansion history: H(z) = 97±62 km sec^(−1) Mpc^(−1) at z ≃ 0.5 and H(z) = 90±40 km sec^(−1) Mpc^(−1) at z ≃ 0.9. We discuss the uncertainty in the expansion history determination that arises from uncertainties in the synthetic stellar-population models. We then use these new measurements in concert with cosmic-microwave-background (CMB) measurements to constrain cosmological parameters, with a special emphasis on dark-energy parameters and constraints to the curvature. In particular, we demonstrate the usefulness of direct H(z) measurements by constraining the dark-energy equation of state parameterized by w_0 and w_a and allowing for arbitrary curvature. Further, we also constrain, using only CMB and H(z) data, the number of relativistic degrees of freedom to be 4±0.5 and their total mass to be < 0.2 eV, both at 1σ.

Indigenous Cosmopolitics in the Andes: Conceptual Reflections Beyond "Politics"

Abstract: In Latin America indigenous politics has been branded as “ethnic politics.” Its activism is interpreted as a quest to make cultural rights prevail. Yet, what if “culture” is insufficient, even an inadequate notion, to think the challenge that indigenous politics represents? Drawing inspiration from recent political events in Peru—and to a lesser extent in Ecuador and Bolivia—where the indigenous–popular movement has conjured sentient entities (mountains, water, and soil—what we call “nature”) into the public political arena, the argument in this essay is threefold. First, indigeneity, as a historical formation, exceeds the notion of politics as usual, that is, an arena populated by rational human beings disputing the power to represent others vis-a-vis the state. Second, indigeneity's current political emergence—in oppositional antimining movements in Peru and Ecuador, but also in celebratory events in Bolivia—challenges the separation of nature and culture that underpins the prevalent notion of politics and its according social contract. Third, beyond “ethnic politics” current indigenous movements, propose a different political practice, plural not because of its enactment by bodies marked by gender, race, ethnicity or sexuality (as multiculturalism would have it), but because they conjure nonhumans as actors in the political arena.

The CP-conserving two-Higgs-doublet model: the approach to the decoupling limit

Abstract: A CP-even neutral Higgs boson with standard-model-like couplings may be the lightest scalar of a two-Higgs-doublet model. We study the decoupling limit of the most general CP-conserving two-Higgs-doublet model, where the mass of the lightest Higgs scalar is significantly smaller than the masses of the other Higgs bosons of the model. In this case, the properties of the lightest Higgs boson are nearly indistinguishable from those of the standard model Higgs boson. The first nontrivial corrections to Higgs boson couplings in the approach to the decoupling limit are also evaluated. The importance of detecting such deviations in precision Higgs boson measurements at future colliders is emphasized. We also clarify the case in which a neutral Higgs boson can possess standard-model-like couplings in a regime where the decoupling limit does not apply. The two-Higgs-doublet sector of the minimal supersymmetric model illustrates many of the above features.