University of Delaware

About: University of Delaware is a education organization based out in Newark, Delaware, United States. It is known for research contribution in the topics: Population & Catalysis. The organization has 22223 authors who have published 54810 publications receiving 2049136 citations. The organization is also known as: University of Delaware Emergency Care Unit & UD.

Competition among marine phytoplankton for different chelated iron species

Abstract: Dissolved-iron availability plays a critical role in controlling phytoplankton growth in the oceans1,2 The dissolved iron is overwhelmingly (∼99%) bound to organic ligands with a very high affinity for iron3,4,5, but the origin, chemical identity and biological availability of this organically complexed Fe is largely unknown6 The release into sea water of complexes that strongly chelate iron could result from the inducible iron-uptake systems of prokaryotes (siderophore complexes)7,8,9 or by processes such as zooplankton-mediated degradation and release of intracellular material (porphyrin complexes) Here we compare the uptake of siderophore- and porphyrin-complexed 55Fe by phytoplankton, using both cultured organisms and natural assemblages Eukaryotic phytoplankton efficiently assimilate porphyrin-complexed iron, but this iron source is relatively unavailable to prokaryotic picoplankton (cyanobacteria) In contrast, iron bound to a variety of siderophores is relatively more available to cyanobacteria than to eukaryotes, suggesting that the two plankton groups exhibit fundamentally different iron-uptake strategies Prokaryotes utilize iron complexed to either endogenous7,8,9 or exogenous siderophores9, whereas eukaryotes may rely on a ferrireductase system10,11 that preferentially accesses iron chelated by tetradentate porphyrins, rather than by hexadentate siderophores Competition between prokaryotes and eukaryotes for organically-bound iron may therefore depend on the chemical nature of available iron complexes, with consequences for ecological niche separation, plankton community size-structure and carbon export in low-iron waters

Nanostructured electrodes for high-performance pseudocapacitors.

Abstract: The depletion of traditional energy resources as well as the desire to reduce high CO(2) emissions associated with energy production means that energy storage is now becoming more important than ever. New functional electrode materials are urgently needed for next-generation energy storage systems, such as supercapacitors or batteries, to meet the ever increasing demand for higher energy and power densities. Advances in nanotechnology are essential to meet those future challenges. It is critical to develop ways of synthesizing new nanomaterials with enhanced properties or combinations of properties to meet future challenges. In this Minireview we discuss several important recent studies in developing nanostructured pseudocapacitor electrodes, and summarize three major parameters that are the most important in determining the performance of electrode materials. A technique to optimize these parameters simultaneously and to achieve both high energy and power densities is also introduced.

Towards automatically generating summary comments for Java methods

Abstract: Studies have shown that good comments can help programmers quickly understand what a method does, aiding program comprehension and software maintenance. Unfortunately, few software projects adequately comment the code. One way to overcome the lack of human-written summary comments, and guard against obsolete comments, is to automatically generate them. In this paper, we present a novel technique to automatically generate descriptive summary comments for Java methods. Given the signature and body of a method, our automatic comment generator identifies the content for the summary and generates natural language text that summarizes the method's overall actions. According to programmers who judged our generated comments, the summaries are accurate, do not miss important content, and are reasonably concise.