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Lancret helices  [PDF]
Alexandre F. da Fonseca,C. P. Malta
Physics , 2005,
Abstract: Helical configurations of inhomogeneous symmetric rods with non-constant bending and twisting stiffness are studied within the framework of the Kirchhoff rod model. From the static Kirchhoff equations, we obtain a set of differential equations for the curvature and torsion of the centerline of the rod and the Lancret's theorem is used to find helical solutions. We obtain a free standing helical solution for an inhomogeneous rod whose curvature and torsion depend on the form of variation of the bending coefficient along the rod. These results are obtained for inhomogeneous rods without intrinsic curvature, and for a particular case of intrinsic curvature.
The Guitar, the Musette and Meaning in the fêtes galantes of Watteau
John Weretka
EMAJ : Electronic Melbourne Art Journal , 2008,
Abstract: This paper examines the depiction of the guitar and musette in the fêtes galantes of Watteau by considering the theoretical, musical and literary evidence for the reception of these instruments in Watteau’s culture. Documentary evidence suggests that the presence of the guitar and musette in the fêtes galantes may provide a tool for reading the nuances of these contested images.
La Le on de géographie, un tableau peint par Girodet en 1803
Jean-Pierre Chevalier
M@ppemonde , 2005,
Abstract: Girodet’s painting the Geography Lesson depicts a bourgeois teaching his son with the use of a globe. This slice-of-life scene raises questions about the place of globes and maps in painting. It provides information about the content and methods of geography teaching at the turn of the 19th century.
Management of distal tibial intra-articular fractures with circular external fixation
G. Lovisetti,M. A. Agus,F. Pace,D. Capitani,F. Sala
Strategies in Trauma and Limb Reconstruction , 2009, DOI: 10.1007/s11751-009-0050-7
Abstract: The treatment of tibial plafond fractures requires careful management of the soft tissue envelope, reconstruction of the articular surface and stable fixation with minimal additional damage. Thirty cases of AO type 43 C tibial fractures were treated by transosseous osteosynthesis (Ilizarov technique). The external fixator constructs used were Ilizarov (Transosseous osteosynthesis: theoretical and clinical aspects of the regeneration and growth of tissue, Springer, Berlin, 1992) and Sheffield (Classification AO des fractures, Springer, Berlin, 1987) circular fixator systems. All tibial plafond fractures healed. Using radiological criteria for assessment of reduction of the articular fragments and the clinical scoring system described by Teeny and Wiss, there were excellent and good restoration of articular structure in 27 cases and good clinical results in 14. This treatment method compares well with previous published series and is to be recommended for this group of difficult fractures.
General Helices of AW(k)-Type in the Lie Group  [PDF]
Dae Won Yoon
Journal of Applied Mathematics , 2012, DOI: 10.1155/2012/535123
Abstract: We study curves of AW(k)-type in the Lie group G with a bi-invariant metric. Also, we characterize general helices in terms of AW(k)-type curve in the Lie group G. 1. Introduction The geometry of curves and surfaces in a 3-dimensional Euclidean space represented for many years a popular topic in the field of classical differential geometry. One of the important problems of the curve theory is that of Bertrand-Lancret-de Saint Venant saying that a curve in is of constant slop; namely, its tangent makes a constant angle with a fixed direction if and only if the ratio of torsion and curvature is a constant. These curves are said to be general helices. If both and are nonzero constants, the curve is called cylindrical helix. Helix is one of the most fascinating curves in science and nature. Scientists have long held a fascinating, sometimes bordering on mystical obsession for helical structures in nature. Helices arise in nanosprings, carbon nanotubes, -helices, DNA double and collagen triple helix, the double helix shape is commonly associated with DNA, since the double helix is structure of DNA. The problem of Bertrand-Lancret-de Saint Venant was generalized for curves in other 3-dimensional manifolds—in particular space forms or Sasakian manifolds. Such a curve has the property that its tangent makes a constant angle with a parallel vector field on the manifold or with a Killing vector field, respectively. For example, a curve in a 3-dimensional space form is called a general helix if there exists a Killing vector field with constant length along and such that the angle between and is a non-zero constant (see [1]). A general helix defined by a parallel vector field was studied in [2]. Moreover, in [3] it is shown that general helices in a 3-dimensional space form are extremal curvatures of a functional involving a linear combination of the curvature, the torsion, and a constant. General helices also called the Lancret curves are used in many applications (e.g., [4–7]). The notion of AW(k)-type submanifolds was introduced by Arslan and West in [8]. In particular, many works related to curves of AW(k)-type have been done by several authors. For example, in [9, 10] the authors gave curvature conditions and charaterizations related to these curves in . Also, in [11] they investigated curves of AW(k) type in a 3-dimensional null cone and gave curvature conditions of these kinds of curves. However, to the author’s knowledge, there is no article dedicated to studying the notion of AW(k)-type curves immersed in Lie group. In this paper, we investigate curvature
Quelques poèmes Some Poems  [cached]
Michael Edwards
Revue LISA / LISA e-journal , 2009, DOI: 10.4000/lisa.64
Abstract: En hommage amical à René Gallet.Ce que dit la mémoireRegardez-moi ce couchant qui s’immobilise,Derrière le Morvan, le Mont Beuvray disparu,Store vénitien que l’on a soudain baissé.Les couleurs du spectre montent vers le CielPar degrés, barreau après barreau sur l’échelleDes anges rêveurs, et le vert au milieu.Hourra pour la blancheur qui se manifeste,Pureté dans les pures nuances de l’ici,Lumière du principe visible à son déclin.Souvenir de voyageTaupe sous le plafond des feuilles, la voiture...
Personalidade artística nos negócios mundanos: a celebra o do "gosto do povo" em Jo osinho Trinta
Edson Farias
Sociedade e Estado , 2012,
Abstract: Ao escrever Mozart: a sociologia de um gênio e A Peregrina o de Watteau à Ilha do Amor, Norbert Elias deixou importante legado ao tratamento sociológico da forma o das subjetividades artísticas e das express es estético-culturais, a partir do problema em torno da rela o entre transforma o e conserva o sócio-históricas, mas do ponto de vista das possibilidades e limites na conduta de indivíduos. Desse modo, neste artigo, a proposta de focar a trajetória de Jo osinho Trinta, no ambito da cultura urbana do Carnaval do Rio de Janeiro, situa-se na contrapartida da aplica o do modelo figuracional e, assim, voltarmos à discuss o sobre a funcionalidade arte-cultura enquanto espa o estratégico à catalisa o de valores e à produ o e difus o de significados. Isso, em busca das duas seguintes quest es: Que dinamica sócio-histórica é caracterizada pela ascendência do gosto popular na valora o do fazer e dos bens artístico-culturais? E, no reverso da medalha, em que medida esse mesmo processo se traduz na rela o entre personalidade artística e negócios mundanos, encarnada na figura histórica do carnavalesco? When writing Mozart: The Sociology of a Genius and Watteau's Pilgrimage to the Island of Love, Norbert Elias left an important legacy to the sociological treatment of the formation of artistic subjectivities and aesthetic and cultural expressions, coming from the problems surrounding the relationship between processing and preserving the socio-historical aspect from the standpoint of the possibilities and limitations in the conduct of individuals. Thus, in this article, the propose of focusing on the trajectory of Jo osinho Trinta within the urban culture of Carnival in Rio de Janeiro is the counterpart of the application of the figurational model and thus to return to the discussion on the feature art-culture as a strategic area of catalysis of values and for the production and dissemination of meanings. This, in search of the following two questions: Are that socio-historical dynamics characterized by the advance of popular taste in the valuation of the doings and artistic and cultural assets? And, on the other side, in which extent is that process reflected in the relationship between artistic personality and worldly affairs, embodied in the historical figure of the "carnavalesco"?
External fixation combined with limited internal fixation in the treatment of pilon tibia fractures  [PDF]
Golubovi? Zoran,Ma?ukanovi?-Golubovi? Lana,Stojiljkovi? Predrag,Jovanovi? Jovica
Vojnosanitetski Pregled , 2007, DOI: 10.2298/vsp0705307g
Abstract: Background/Aim. Intraarticular fractures of the tibial plafond (pilon fractures) belong to the group of most severe fractures. They are usually caused by high-energy trauma and frequently associated with a marked soft-tissue damage. Surgical treatment has replaced the traditional nonoperative treatment. The aim of this study was to present the results of the treatment of distal tibial intraarticular fracture by the use of internal fixation, as well as the combination of minimal internal fixation and external fixation. Methods. The study included 47 patients with pilon tibia fractures who went through at the Clinic for Orthopedics and Traumatology, School of Medicine, Ni (1995-2004). Within the analyzed group there were 33 (70.2%) males and 14 (29.8%) females. The patients mean age was 45.8 years. In the first group, which consisted of 22 patients, open reduction and internal fixation of both the tibia and the fibula was performed in the two separate incisions. The second group consisted of 25 patients managed with external fixation by external fixator "Mitkovi " with limited internal fixation. Besides external fixation, a minimal internal fixation was performed by the use of Kirschner wires and screws. The patients were followed-up inside a 24-months-period. Results. The obtained was a substantially high number of complications after open reduction and internal fixation in the group of patients. There was no difference in a long-term clinical outcome. Postoperative osteitis, as the most severe complication in the management of closed pilon tibia fractures, was not registered in the second group. Conclusion. Considering the results obtained in this study, it can be concluded that external fixation by the "Mitkovi " external fixator with the minimal internal fixation is a satisfactory method for the treatment of fractures of the tibial plafond causing less complications than internal fixation. .
Utility of double-contrast multidetector CT scans to assess cartilage thickness after tibial plafond fracture
Thaddeus P Thomas, Christopher J Van Hofwegen, Donald D Anderson, et al
Orthopedic Research and Reviews , 2009, DOI: http://dx.doi.org/10.2147/ORR.S7387
Abstract: ility of double-contrast multidetector CT scans to assess cartilage thickness after tibial plafond fracture Methodology (3859) Total Article Views Authors: Thaddeus P Thomas, Christopher J Van Hofwegen, Donald D Anderson, et al Published Date November 2009 Volume 2009:1(Default) Pages 23 - 29 DOI: http://dx.doi.org/10.2147/ORR.S7387 Thaddeus P Thomas1,2, Christopher J Van Hofwegen1, Donald D Anderson1,2, Thomas D Brown1,2, J Lawrence Marsh1 1Department of Orthopedics and Rehabilitation, 2Department of Biomedical Engineering, The University of Iowa, Iowa City, IA, USA Abstract: The pathophysiology of posttraumatic osteoarthritis (PTOA) after intraarticular fractures is poorly understood. Pursuit of a better understanding of this disease is complicated by inability to accurately monitor its onset, progression and severity. Common radiographic methods used to assess PTOA do not provide sufficient image quality for precise cartilage measurements. Double-contrast multidetector computed tomography (MDCT) is an alternative method that may be useful, since it produces high-quality images in normal ankles. The purpose of this study was to assess this technique’s performance in assessing cartilage maintenance in ankles with an intraarticular fracture. Thirty-six tibial plafond fractures were followed over two years, with 31 MDCTs being obtained four months after injury, and 22 MDCTs after two years. Unfortunately, clinical results with this technique were unreliable due to pathology (presumed arthrofibrosis) and technical problems (pooling of contrast). The arthrofibrosis that developed in many patients inhibited proper joint access and contrast infiltration, although high-quality images were obtained in 11 patients. In this patient subset, in which focal regions of cartilage degeneration could be visualized, thickness could be measured with a high degree of fidelity. While thus useful in selected instances, double-contrast MDCT was too unreliable to be recommended to assess these particular types of injuries.
Slant Curves in the Unit Tangent Bundles of Surfaces  [PDF]
Zhong Hua Hou,Lei Sun
ISRN Geometry , 2013, DOI: 10.1155/2013/821429
Abstract: Let be a surface and let be the unit tangent bundle of endowed with the Sasaki metric. We know that any curve in consist of a curve in and as unit vector field along . In this paper we study the geometric properties and satisfying when is a slant geodesic. 1. Introduction Let be a 3-dimensional contact metric manifold. The slant curves in are generalization of Legendrian curves which form a constant angle with the Reeb vector field . Cho et al. [1] studied Lancret type problem for curves in Sasakian 3-manifold. They showed that a curve is slant if and only if is constant where and are torsion and curvature of , respectively, and they also gave some examples of slant curves. One can find some other papers about slant curves in almost contact metric manifolds. For examples, C?lin et al. [2] studied the slant curves in -Kenmotsu manifolds. In [3], C?lin and Crasmareanu studied slant curves in normal almost contact manifolds. Let be a Riemannian manifold. Sasaki [4, 5] studied the geometries of endowed with the Sasaki metric and introduced the almost complex structure in which is compatible with . Tashiro [6] constructed an almost contact metric structure in the unit tangent bundle of which is induced from the almost complex structure in . Klingenberg and Sasaki [7] studied geodesics in the unit tangent bundle of -sphere endowed with Sasaki metric and showed that is isometric to . Sasaki [8] studied the geodesics on the unit tangent bundles over space forms. In this paper, we study the slant geodesics in the unit tangent bundle of some surface . For any curve in , let be the tangent vector field of and let be the sectional curvature of at , we have the following theorems. Theorem 1. Let be a Legendrian geodesic parameterized by arc length in with domain . If the set consisting of points such that is discrete, then is a geodesic of velocity and is the normal direction of in . Theorem 2. Let be a slant geodesic parameterized by arc length in which is not Legendrian. Under the assumptions of as in Theorem 1, we have the following.(1)If , then is a geodesic of velocity 2 and is a parallel vector field along .(2)If , then is a curve of velocity with constant curvature . 2. Preliminaries Firstly, we introduce the (almost) contact metric structure on a Riemannian manifold of odd dimension. With the same notations as in [9]; let be a real -dimensional manifold and the Lie algebra of vector fields on . An almost cocomplex structure on is defined by a (1,1)-tensor , a vector field and a 1-form on such that for any point we have where denotes the identity
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