Phytoplankton assemblages within the Chesapeake Bay plume and adjacent waters of the continental shelf

The Chesapeake Bay plume was identified and plotted in relation to the presence and high concentrations of phytoplankton assemblages. Seasonal differences occurred within the plume during the collection period, with Skeletonema costatum and an ultraplankton component the dominant forms. Patchiness was found along the transects, with variations in composition and concentrations common on consecutive day sampling within the plume in its movement along the shelf. The presence of 236 species is noted, with their presence indicated for plume and shelf stations during the March, June, and October 1980 collections

The challenges of viewpoint-taking when learning a sign language: Data from the 'frog story' in British Sign Language

Little is known about how hearing adults learn sign languages. Our objective in this study was to investigate how learners of British Sign Language (BSL) produce narratives, and we focused in particular on viewpoint-taking. Twenty-three intermediate-level learners of BSL and 10 deaf native/early signers produced a narrative in BSL using the wordless picture book Frog, where are you? (Mayer, 1969). We selected specific episodes from part of the book that provided rich opportunities for shifting between different characters and taking on different viewpoints. We coded for details of story content, the frequency with which different viewpoints were used and how long those viewpoints were used for, and the numbers of articulators that were used simultaneously. We found that even though learners’ and deaf signers’ narratives did not differ in overall duration, learners’ narratives had less content. Learners used character viewpoint less frequently than deaf signers. Although learners spent just as long as deaf signers in character viewpoint, they spent longer than deaf signers in observer viewpoint. Together, these findings suggest that character viewpoint was harder than observer viewpoint for learners. Furthermore, learners were less skilled than deaf signers in using multiple articulators simultaneously. We conclude that challenges for learners of sign include taking character viewpoint when narrating a story and encoding information across multiple articulators simultaneously

Direct Laser Sintering of Metals

The use of a directed laser bealn source to selectively sinter multiple layers of binderless metal powder for the purposes of rapid prototyping is described. The work in this paper is restricted to -325 mesh iron powder, which was sintered using a C\V 50 W Nd:YAG laser to approximately 3.5% density. A subsequent post-treatlnent was perfornled to achieve a fully dense saulple. It is envisioned that such a system can be used to manufacture functional metallic prototypes directly from CAD without part-specific tooling.Mechanical Engineerin

Search for a Heavy Particle Decaying into an Electron and a Muon with the ATLAS Detector in √s = 7 TeV pp collisions at the LHC

This Letter presents the first search for a heavy particle decaying into an e^±μ^∓ final state in √s=7  TeV pp collisions at the LHC. The data were recorded by the ATLAS detector during 2010 and correspond to a total integrated luminosity of 35  pb^(-1). No excess above the standard model background expectation is observed. Exclusions at 95% confidence level are placed on two representative models. In an R-parity violating supersymmetric model, tau sneutrinos with a mass below 0.75 TeV are excluded, assuming all R-parity violating couplings are zero except λ'_(311)=0.11 and λ_(312)=0.07. In a lepton flavor violating model, a Z′-like vector boson with masses of 0.70–1.00 TeV and corresponding cross sections times branching ratios of 0.175–0.183 pb is excluded. These results extend to higher mass R-parity violating sneutrinos and lepton flavor violating Z’s than previous constraints from the Tevatron

Information Complements, Substitutes, and Strategic Product Design

Competitive maneuvering in the information economy has raised a pressing question: how can firms raise profits by giving away products for free? This paper provides a possible answer and articulates a strategy space for information product design. Free strategic complements can raise a firm's own profits while free strategic substitutes can lower profits for competitors. We introduce a formal model of cross-market externalities based in textbook economics -- a mix of Katz & Shapiro network effects, price discrimination, and product differention -- that leads to novel strategies such as an eagerness to enter into Bertrand price competition. This combination helps to explain many recent firm strategies such as those of Microsoft, Netscape (AOL), Sun, Adobe, and ID. We also introduce the concept of a ''content-creator'' who adds value for end-consumers but may not be paid directly. Similar to the case of product dumping, this research implies that both firms and policy makers need to consider complex market interactions to grasp information product design and profit maximization. The model presented here argues for three simple and intuitive results. First, a firm can rationally invest in a product it intends to give away into perpetuity even in the absence of competition. The reason is that increased demand in a complementary goods market more than covers the cost of investment in the free goods market. Second, we identify distinct markets for content-providers and end-consumers and show that either can be a candidate for the free good. The decision on which market to charge rests on the relative elasticities as governed by their network externality effects. If the externality effect is sufficiently great, the market with the higher elasticity is the market to subsidize with the free good. It is also possible to charge both markets but to keep one price artificially low. Importantly, the modeling contribution is distinct from tying in the sense that consumers need never purchase both goods -- unlike razors and blades, the products are stand-alone goods. It also differs from multi-market price discrimination in the sense that the firm may extract no consumer surplus from one of the two market segments, implying that this market would have previously gone un-served. Third, a firm can use strategic product design to penetrate a market that becomes competitive post-entry. The threat of entry is credible even in cases where it never recovers its sunk costs directly. The model therefore helps to explain several interesting market behaviors such as free goods, upgrade paths, split versioning, and strategic information substitutes.http://deepblue.lib.umich.edu/bitstream/2027.42/39683/3/wp299.pd

Object oriented studies into artificial space debris

A prototype simulation is being developed under contract to the Royal Aerospace Establishment (RAE), Farnborough, England, to assist in the discrimination of artificial space objects/debris. The methodology undertaken has been to link Object Oriented programming, intelligent knowledge based system (IKBS) techniques and advanced computer technology with numeric analysis to provide a graphical, symbolic simulation. The objective is to provide an additional layer of understanding on top of conventional classification methods. Use is being made of object and rule based knowledge representation, multiple reasoning, truth maintenance and uncertainty. Software tools being used include Knowledge Engineering Environment (KEE) and SymTactics for knowledge representation. Hooks are being developed within the SymTactics framework to incorporate mathematical models describing orbital motion and fragmentation. Penetration and structural analysis can also be incorporated. SymTactics is an Object Oriented discrete event simulation tool built as a domain specific extension to the KEE environment. The tool provides facilities for building, debugging and monitoring dynamic (military) simulations