Institution
University of Arizona
Education•Tucson, Arizona, United States•
About: University of Arizona is a education organization based out in Tucson, Arizona, United States. It is known for research contribution in the topics: Population & Galaxy. The organization has 63805 authors who have published 155998 publications receiving 6854915 citations. The organization is also known as: UA & U of A.
Topics: Population, Galaxy, Star formation, Redshift, Planet
Papers published on a yearly basis
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TL;DR: In this paper, a strong negative relationship between firm-level capital investment and the aggregate level of uncertainty associated with future policy and regulatory outcomes is found, and the relation between policy uncertainty and capital investment is not uniform in the cross section, being significantly stronger for firms with a higher degree of investment irreversibility and for firms more dependent on government spending.
Abstract: Using the policy uncertainty index of Baker, Bloom, and Davis (2013), we document a strong negative relationship between firm-level capital investment and the aggregate level of uncertainty associated with future policy and regulatory outcomes. More importantly, we find evidence that the relation between policy uncertainty and capital investment is not uniform in the cross section, being significantly stronger for firms with a higher degree of investment irreversibility and for firms which are more dependent on government spending. Our results lend empirical support to the notion that policy uncertainty can depress corporate investment by inducing precautionary delays due to investment irreversibility.
1,164 citations
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TL;DR: A computer program is described for calculating the environment and the exposure to solvent of atoms of a protein based on the atomic co-ordinates of the protein and on assumptions like those of Lee & Richards (1971).
1,158 citations
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TL;DR: How the core/shell ratio and overall size of a nanoshell influences its scattering and absorption properties is illustrated and several examples ofnanoshell-based diagnostic and therapeutic approaches are described including the development of Nanoshell bioconjugates for molecular imaging, the use of scattering nanosells as contrast agents for optical coherence tomography (OCT), and the use for absorbing nanoshels in NIR thermal therapy of tumors.
Abstract: Metal nanoshells are a novel type of composite spherical nanoparticle consisting of a dielectric core covered by a thin metallic shell which is typically gold. Nanoshells possess highly favorable optical and chemical properties for biomedical imaging and therapeutic applications. By varying the relative the dimensions of the core and the shell, the optical resonance of these nanoparticles can be precisely and systematically varied over a broad region ranging from the near-UV to the mid-infrared. This range includes the near-infrared (NIR) wavelength region where tissue transmissivity peaks. In addition to spectral tunability, nanoshells offer other advantages over conventional organic dyes including improved optical properties and reduced susceptibility to chemical/thermal denaturation. Furthermore, the same conjugation protocols used to bind biomolecules to gold colloid are easily modified for nanoshells. In this article, we first review the synthesis of gold nanoshells and illustrate how the core/shell ratio and overall size of a nanoshell influences its scattering and absorption properties. We then describe several examples of nanoshell-based diagnostic and therapeutic approaches including the development of nanoshell bioconjugates for molecular imaging, the use of scattering nanoshells as contrast agents for optical coherence tomography (OCT), and the use of absorbing nanoshells in NIR thermal therapy of tumors.
1,157 citations
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01 Aug 1995TL;DR: In the field of remote sensing applications, scientists have developed vegetation indices (VI) for qualitatively and quantitatively evaluating vegetative covers using spectral measurements as mentioned in this paper, where the spectral response of vegetated areas presents a complex mixture of vegetation, soil brightness, environmental effects, shadow, soil color and moisture.
Abstract: In the field of remote sensing applications, scientists have developed vegetation indices (VI) for qualitatively and quantitatively evaluating vegetative covers using spectral measurements. The spectral response of vegetated areas presents a complex mixture of vegetation, soil brightness, environmental effects, shadow, soil color and moisture. Moreover, the VI is affected by spatial‐temporal variations of the atmosphere. Over forty vegetation indices have been developed during the last two decades in order to enhance vegetation response and minimize the effects of the factors described above. This paper summarizes, refers and discusses most of the vegetation indices found in the literature. It presents different existing classifications of indices and proposes to group them in a new classification.
1,155 citations
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TL;DR: Investigation of aphids for vulnerability of the aphid host to a hymenopteran parasitoid, Aphidius ervi, shows that infection confers resistance to parasitoids attack by causing high mortality of developing Parasitoid larvae.
Abstract: Symbiotic relationships between animals and microorganisms are common in nature, yet the factors controlling the abundance and distributions of symbionts are mostly unknown. Aphids have an obligate association with the bacterium Buchnera aphidicola (the primary symbiont) that has been shown to contribute directly to aphid fitness. In addition, aphids sometimes harbor other vertically transmitted bacteria (secondary symbionts), for which few benefits of infection have been previously documented. We carried out experiments to determine the consequences of these facultative symbioses in Acyrthosiphon pisum (the pea aphid) for vulnerability of the aphid host to a hymenopteran parasitoid, Aphidius ervi, a major natural enemy in field populations. Our results show that, in a controlled genetic background, infection confers resistance to parasitoid attack by causing high mortality of developing parasitoid larvae. Compared with uninfected controls, experimentally infected aphids were as likely to be attacked by ovipositing parasitoids but less likely to support parasitoid development. This strong interaction between a symbiotic bacterium and a host natural enemy provides a mechanism for the persistence and spread of symbiotic bacteria.
1,154 citations
Authors
Showing all 64388 results
Name | H-index | Papers | Citations |
---|---|---|---|
Simon D. M. White | 189 | 795 | 231645 |
Julie E. Buring | 186 | 950 | 132967 |
David H. Weinberg | 183 | 700 | 171424 |
Richard Peto | 183 | 683 | 231434 |
Xiaohui Fan | 183 | 878 | 168522 |
Dennis S. Charney | 179 | 802 | 122408 |
Daniel J. Eisenstein | 179 | 672 | 151720 |
David Haussler | 172 | 488 | 224960 |
Carlos S. Frenk | 165 | 799 | 140345 |
Jian-Kang Zhu | 161 | 550 | 105551 |
Tobin J. Marks | 159 | 1621 | 111604 |
Todd Adams | 154 | 1866 | 143110 |
Jane A. Cauley | 151 | 914 | 99933 |
Wei Zheng | 151 | 1929 | 120209 |
Daniel L. Schacter | 149 | 592 | 90148 |