University of California, Santa Cruz

About: University of California, Santa Cruz is a education organization based out in Santa Cruz, California, United States. It is known for research contribution in the topics: Galaxy & Population. The organization has 15541 authors who have published 44120 publications receiving 2759983 citations. The organization is also known as: UCSC & UC, Santa Cruz.

Control-flow integrity

Abstract: Current software attacks often build on exploits that subvert machine-code execution. The enforcement of a basic safety property, Control-Flow Integrity (CFI), can prevent such attacks from arbitrarily controlling program behavior. CFI enforcement is simple, and its guarantees can be established formally even with respect to powerful adversaries. Moreover, CFI enforcement is practical: it is compatible with existing software and can be done efficiently using software rewriting in commodity systems. Finally, CFI provides a useful foundation for enforcing further security policies, as we demonstrate with efficient software implementations of a protected shadow call stack and of access control for memory regions.

Laboratory experiments on speciation: what have we learned in 40 years?

Abstract: We integrate experimental studies attempting to duplicate all or part of the speciation process under controlled laboratory conditions and ask what general conclusions can be made concerning the major models of speciation. Strong support is found for the evolution of reproductive isolation via pleiotropy and/or genetic hitchhiking with or without allopatry. Little or no support is found for the bottleneck and reinforcement models of speciation. We conclude that the role of geographical separation in generating allopatry (i.e., zero gene flow induced by spatial isolation) has been overemphasized in the past, whereas its role in generating diminished gene flow in combination with strong, discontinuous, and multifarious divergent selection, has been largely unappreciated.

Sn-Doped Hematite Nanostructures for Photoelectrochemical Water Splitting

Abstract: We report on the synthesis and characterization of Sn-doped hematite nanowires and nanocorals as well as their implementation as photoanodes for photoelectrochemical water splitting. The hematite nanowires were prepared on a fluorine-doped tin oxide (FTO) substrate by a hydrothermal method, followed by high temperature sintering in air to incorporate Sn, diffused from the FTO substrate, as a dopant. Sn-doped hematite nanocorals were prepared by the same method, by adding tin(IV) chloride as the Sn precursor. X-ray photoelectron spectroscopy analysis confirms Sn4+ substitution at Fe3+ sites in hematite, and Sn-dopant levels increase with sintering temperature. Sn dopant serves as an electron donor and increases the carrier density of hematite nanostructures. The hematite nanowires sintered at 800 °C yielded a pronounced photocurrent density of 1.24 mA/cm2 at 1.23 V vs RHE, which is the highest value observed for hematite nanowires. In comparison to nanowires, Sn-doped hematite nanocorals exhibit smaller fe...