8,970 research outputs found
RECONSTITUTION OF ALLOPHYCOCYANIN FROM Mastigocladus laminosus WITH ISOLATED LINKER POLYPEPTIDE
The core linker polypeptide Lc 8.9 was isolated from Mastigocladus laminosus and purified on a preparative scale. A method for the reconstitution of allophycocyanin (AP)—linker complexes from isolated polypeptides was developed. The complex (αAP(βAP)3 Lc 8.9 was reconstituted and compared to (αAPβAP) and (αAPβAP)3 by sucrose density gradient ultracentrifugation, absorption, fluorescence emission and circular dichroism spectroscopy. Differences in the spectra of reconstituted and of directly isolated AP complexes are discussed
Computational and theoretical aspects of a grain-boundary model at finite deformations
A model to describe the role of grain boundaries in the overall response of a polycrystalline material at small length scales subject to finite deformations is presented. Three alternative thermodynamically consistent plastic flow relations on the grain boundary are derived and compared using a series of numerical experiments. The numerical model is obtained by approximating the governing relations using the finite element method. In addition, the infinitesimal and finite deformation theories are compared, and the limitations of the former made clear
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Computational and theoretical aspects of a grain-boundary model that accounts for grain misorientation and grain-boundary orientation
A detailed theoretical and numerical investigation of the infinitesimal
single-crystal gradient plasticity and grain-boundary theory of Gurtin (2008)
"A theory of grain boundaries that accounts automatically for grain
misorientation and grain-boundary orientation". Journal of the Mechanics and
Physics of Solids 56 (2), 640-662, is performed. The governing equations and
flow laws are recast in variational form. The associated incremental problem is
formulated in minimization form and provides the basis for the subsequent
finite element formulation. Various choices of the kinematic measure used to
characterize the ability of the grain boundary to impede the flow of
dislocations are compared. An alternative measure is also suggested. A series
of three-dimensional numerical examples serve to elucidate the theory
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Cutting Through the Online Review Jungle — Investigating Selective eWOM Processing
Consumers frequently rely on online reviews, a prominent form of electronic word-of-mouth (eWOM), before making a purchase decision. However, consumers are usually confronted with hundreds of reviews for a single product or service, as well as rich information cues on online review websites (review texts, helpfulness ratings, author information, etc.). In turn, consumers face more information cues on online review websites than they can or want to process, and are likely to proceed selectively. This paper investigates selective processing of such eWOM information cues. Results of Study 1, an exploratory study using verbal protocols, confirm that consumers display selective eWOM processing patterns and are able to articulate them. Study 2 develops and applies a measurement instrument to capture these patterns. A subsequent cluster analysis on members of a large-scale online panel (N = 2,295) indicates five prominent eWOM processing types, termed “The Efficients”, “The Meticulous”, “The Quality-Evaluators”, “The Cautious Critics”, and “The Swift Pessimists”. Insights of this research can help firms to better understand consumers' eWOM processing and improve the user-friendliness of online review websites
The Six Frigates: The Epic History of the Founding of the U.S. Navy
Many books have been written about the history of the American navy, but this one is of particular excellence. While truly a scholarly work, this book contains many attributes of a historical novel. Any reader with an interest in either the U.S. Navy or early American history will find it hard to put down. Toll begins his story with a review of the Continental navy and its limited value during the American Revolution, then moves seamlessly into the post- revolutionary period. America’s colonial experience and the needs of the newly formed nation had a direct effect on the founding of a navy
Configurable Process Models as a Basis for Reference Modeling
Off-the-shelf packages such as SAP need to be configured to suit the requirements of an organization. Reference models support the configuration of these systems. Existing reference models use rather traditional languages. For example, the SAP reference model uses Eventdriven Process Chains (EPCs). Unfortunately, traditional languages like EPCs do not capture the configuration-aspects well. Consider for example the concept of "choice" in the control-flow perspective. Although any process modeling language, including EPCs, offers a choice construct (e.g., the XOR connector in EPCs), a single construct will not be able to capture the time dimension, scope, and impact of a decision. Some decisions are taken at run-time for a single case while other decisions are taken at build-time impacting a whole organization and all current and future cases. This position paper discusses the need for configurable process models as a basic building block for reference modeling. The focus is on the control-flow perspective. © Springer-Verlag Berlin Heidelberg 2006
Robust Flows over Time: Models and Complexity Results
We study dynamic network flows with uncertain input data under a robust
optimization perspective. In the dynamic maximum flow problem, the goal is to
maximize the flow reaching the sink within a given time horizon , while flow
requires a certain travel time to traverse an edge.
In our setting, we account for uncertain travel times of flow. We investigate
maximum flows over time under the assumption that at most travel times
may be prolonged simultaneously due to delay. We develop and study a
mathematical model for this problem. As the dynamic robust flow problem
generalizes the static version, it is NP-hard to compute an optimal flow.
However, our dynamic version is considerably more complex than the static
version. We show that it is NP-hard to verify feasibility of a given candidate
solution. Furthermore, we investigate temporally repeated flows and show that
in contrast to the non-robust case (that is, without uncertainties) they no
longer provide optimal solutions for the robust problem, but rather yield a
worst case optimality gap of at least . We finally show that the optimality
gap is at most , where and are newly introduced
instance characteristics and provide a matching lower bound instance with
optimality gap and . The results obtained in
this paper yield a first step towards understanding robust dynamic flow
problems with uncertain travel times
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