7,681 research outputs found
Wrist joint assembly
A wrist joint assembly is provided for use with a mechanical manipulator arm for finely positioning an end-effector carried by the wrist joint on the terminal end of the manipulator arm. The wrist joint assembly is pivotable about a first axis to produce a yaw motion, a second axis is to produce a pitch motion, and a third axis to produce a roll motion. The wrist joint assembly includes a disk segment affixed to the terminal end of the manipulator arm and a first housing member, a second housing member, and a third housing member. The third housing member and the mechanical end-effector are moved in the yaw, pitch, and roll motion. Drive means are provided for rotating each of the housings about their respective axis which includes a cluster of miniature motors having spur gears carried on the output drive shaft which mesh with a center drive gear affixed on the housing to be rotated
Supersymmetric Musings on the Predictivity of Family Symmetries
We discuss the predictivity of family symmetries for the soft supersymmetry
breaking parameters in the framework of supergravity. We show that unknown
details of the messenger sector and the supersymmetry breaking hidden sector
enter into the soft parameters, making it difficult to obtain robust
predictions. We find that there are specific choices of messenger fields which
can improve the predictivity for the soft parameters.Comment: 20 pages, 5 figure
Negotiating Inefficient Compromises: Is Less Better than More?
Significant efforts are made to design and implement decision and negotiation support systems to identify efficient alternatives. The underlying assumption is that decision-makers prefer an efficient alternative over an inefficient one. Experimental studies indicate that people often accept inefficient compromises and are unwilling to improve them even if prompted to do so. This report presents preliminary results for the analysis of 605 bilateral negotiations in which only 20.8% of negotiators who achieved an inefficient compromise entered the post-settlement phase in an attempt to improve the compromise
Border ownership selectivity in human early visual cortex and its modulation by attention
Natural images are usually cluttered because objects occlude one another. A critical aspect of recognizing these visual objects is to identify the borders between image regions that belong to different objects. However, the neural coding of border ownership in human visual cortex is largely unknown. In this study, we designed two simple but compelling stimuli in which a slight change of contextual information could induce a dramatic change of border ownership. Using functional MRI adaptation, we found that border ownership selectivity in V2 was robust and reliable across subjects, and it was largely dependent on attention. Our study provides the first human evidence that V2 is a critical area for the processing of border ownership and that this processing depends on the modulation from higher-level cortical areas. Copyright © 2009 Society for Neuroscience
On Waylen's regular axisymmetric similarity solutions
We review the similarity solutions proposed by Waylen for a regular
time-dependent axisymmetric vacuum space-time, and show that the key equation
introduced to solve the invariant surface conditions is related by a Baecklund
transform to a restriction on the similarity variables. We further show that
the vacuum space-times produced via this path automatically possess a (possibly
homothetic) Killing vector, which may be time-like.Comment: 8 pages, LaTeX2
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A mass spectrometry-guided genome mining approach for natural product peptidogenomics.
Peptide natural products show broad biological properties and are commonly produced by orthogonal ribosomal and nonribosomal pathways in prokaryotes and eukaryotes. To harvest this large and diverse resource of bioactive molecules, we introduce here natural product peptidogenomics (NPP), a new MS-guided genome-mining method that connects the chemotypes of peptide natural products to their biosynthetic gene clusters by iteratively matching de novo tandem MS (MS(n)) structures to genomics-based structures following biosynthetic logic. In this study, we show that NPP enabled the rapid characterization of over ten chemically diverse ribosomal and nonribosomal peptide natural products of previously unidentified composition from Streptomycete bacteria as a proof of concept to begin automating the genome-mining process. We show the identification of lantipeptides, lasso peptides, linardins, formylated peptides and lipopeptides, many of which are from well-characterized model Streptomycetes, highlighting the power of NPP in the discovery of new peptide natural products from even intensely studied organisms
Jacobi multipliers, non-local symmetries and nonlinear oscillators
Constants of motion, Lagrangians and Hamiltonians admitted by a family of
relevant nonlinear oscillators are derived using a geometric formalism. The
theory of the Jacobi last multiplier allows us to find Lagrangian descriptions
and constants of the motion. An application of the jet bundle formulation of
symmetries of differential equations is presented in the second part of the
paper. After a short review of the general formalism, the particular case of
non-local symmetries is studied in detail by making use of an extended
formalism. The theory is related to some results previously obtained by
Krasil'shchi, Vinogradov and coworkers. Finally the existence of non-local
symmetries for such two nonlinear oscillators is proved.Comment: 20 page
Eefde: identiteit en toekomst van een woondorp in het groen
In aanvulling op het onlangs afgeronde Dorpsplan Eefde had de dorpsraad van dit Gelderse dorp behoefte aan een visie voor de sociaal-ruimtelijke ontwikkeling voor Eefde. Dit met name in het licht van de grote infrastructurele projecten die in Eefde gepland staan voor de komende jaren. Het is in dit kader dat de Dorpsraad zich tot de Wetenschapswinkel wendde met het verzoek na te denken over een toekomstvisie voor het dorp, maar dan wel één die nadrukkelijk verankerd is in de Eefdese realiteit
Algebraic properties of Gardner's deformations for integrable systems
An algebraic definition of Gardner's deformations for completely integrable
bi-Hamiltonian evolutionary systems is formulated. The proposed approach
extends the class of deformable equations and yields new integrable
evolutionary and hyperbolic Liouville-type systems. An exactly solvable
two-component extension of the Liouville equation is found.Comment: Proc. conf. "Nonlinear Physics: Theory and Experiment IV" (Gallipoli,
2006); Theor. Math. Phys. (2007) 151:3/152:1-2, 16p. (to appear
Understanding The Hobbit: the cross-national and cross-linguistic reception of a global media product in Belgium, France and the Netherlands
The Hobbit franchise, as many global media products, reaches audiences worldwide. Audience members apparently consume a uniform media product. But do they? The World Hobbit Project offers a new and exciting opportunity to explore differences and similarities, for it provides us with audiences' understandings of the trilogy across languages and nationalities. In this paper we conduct a statistical analysis on differences and similarities in understandings of The Hobbit trilogy between Belgium, the Netherlands, and France – both in what audiences do and do not feel The Hobbit films to be. Analyzing this particular region in Europe provides an extraordinary opportunity, for The World Hobbit project allows us to compare on the language level (the Dutch and French-speaking Belgian regions with respectively the Netherlands and France), as well as on the level of national identities (comparing the three countries amongst each other). In doing so, we are able to further understand what informs geographical and linguistic differences in the consumption of a uniform media product. As such, this paper touches upon cultural hegemony, cross-border flows of fiction, language and cultural proximity
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