1,262 research outputs found

    Pose consensus based on dual quaternion algebra with application to decentralized formation control of mobile manipulators

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    This paper presents a solution based on dual quaternion algebra to the general problem of pose (i.e., position and orientation) consensus for systems composed of multiple rigid-bodies. The dual quaternion algebra is used to model the agents' poses and also in the distributed control laws, making the proposed technique easily applicable to time-varying formation control of general robotic systems. The proposed pose consensus protocol has guaranteed convergence when the interaction among the agents is represented by directed graphs with directed spanning trees, which is a more general result when compared to the literature on formation control. In order to illustrate the proposed pose consensus protocol and its extension to the problem of formation control, we present a numerical simulation with a large number of free-flying agents and also an application of cooperative manipulation by using real mobile manipulators

    Dietary modifications for infantile colic

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    Infantile colic can be defined as periods of inconsolable, unexplained, and incessant crying in a seemingly healthy infant that, quite understandably, leads to exhausted, frustrated, and concerned parents seeking to comfort their child (Landgren 2010). The prevalence of excessive crying varies according to the definition used although, most often, it peaks during the second month of life,with a prevalence of 1.5%to 11.9%(Reijneveld 2001).Traditionally, the definition of the condition was based on the rule of three (Wessel 1954): that is, unexplained episodes of paroxysmal crying for more than three hours per day, for three days per week, for at least three weeks. More recently a new definition has been proposed. It refers to a clinical condition of fussing and crying for at least one week in an otherwise healthy infant (Hyman 2006). Colic can be graded as mild, moderate, or severe, though there is no consensus for this classification. Colic can affect up to 10% to 30% of infants worldwide (Clifford 2002; Rosen 2007)

    Molecular diagnosis of grapevine fleck virus

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    A digoxigenin-labelled riboprobe was developed for the detection of grapevine fleck virus (GFkV) in infected tissues of grapevine leaves, roots and canes. The probe was GFkV-specific and was successfully used for virus identification both with dot spot assays, using alkali-treated crude sap, and tissue blot assays, using cross and longitudinal sections of leaf petioles. Primers designed for the amplification by reverse transcription-polymerase chain reaction of a viral genome fragment 243 nucleotides in size, gave also positive and repeatable results. These newly developed molecular-based detection tools extend the range of available procedures for the sensitive identification of GFkV in naturally infected hosts

    Viroids of grapevines in Italy

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    Rebviroide in ItalienEs wird über das Vorkommen niedermolekularer RNAs bei 48 Vitis-vinifera-Stämmen und 15 amerikanischen Vitis-Arten und Kreuzungen aus Italien, Osteuropa, Mittelmeer- und Nahost-Ländern berichtet. In den Sämlingen zweier Sorten wurden keine derartigen RNAs gefunden. Aufgrund ihres elektrophoretischen Verhaltens wurden diese RNAs vorläufig identifiziert als Grapevine yellow speckle-Viroid (GYSVd), Grapeivine-Viroid 2 (GVd2) und Hop stunt-Viroid (HSVd). Das letztere Viroid löste bei künstlich infizierten Pflanzen von Tomate cv. Rutgers und Gurke cv. Suyo Befallssymptome aus. HSVd, GYSVd und GVd2 wurden in 97, 92 bzw. 11 % der untersuchten Proben wiedergefunden. In der Regel lagen Mischinfektionen vor, wobei die Kombination von HSVd mit GYSVd überwog. Diese beiden Viroide kamen regelmäßig in Reben mit den Symptomen von Yellow speckle oder Vein banding vor. Es wurde keine eindeutige Beziehung zwischen dem Vorkommen eines der Viroide und Rebkrankheiten mit unklarer Ätiologie, wie Vein necrosis oder Fleck, gefunden
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