Is it possible to have mathematics experience in the school courtyard garden? Can we observe plants "with different eyes" and identify the connections between mathematical sciences and plant biology? ...This booklet contains and comments on three interdisciplinary activities that secondary school mathematics and science teachers can conduct in their classrooms, using the group laboratory work method. The proposed activities concern two apparently distant fields: geometry and botany, and are linked to the laboratory kit "Symmetry: mathematics in the garden" (http://specchi.mat.unimi.it/matematica/matematica_in_giardino.html). This work intends to provide teachers, and not only them, with an unusual classification tool based on symmetry and also with a look at topics that are little known to most people and not usually covered in the school curricula, such as floral diagrams and phyllotaxis.
The essay confirms the inorganic nature of architecture and, in this way, clarifies the particular mimesis that architecture lays not so much with nature and its forms but with itself. There are ...multiple links with the philosophy that recognizes his role “regent and foundational”. Describing the theoretical dimension of architecture, the contribution reflects on the particular role that theory assumes in the art of building as a way of knowledge and observation and verification in buildings. The role of symmetry – understood as the proportion in the historical development of the art of building since the ancient treatise writers, during the Renaissance until the modern reformulation, to get to the forgetfulness of the role that this compositional procedure assumes in the contemporary world – is discussed. The current condition is unfortunately directed more to the reductio ad imaginem; it should be again addresses to the construction of adequate space and the selection of appropriate forms to represent, through the expressiveness of the construction, reason and essence of architecture.
Teleparallel Gravity (TG) is an alternative theory for gravitation, which is equivalent to General Relativity (GR). However, it is conceptually different. For example in GR geometry replaces the ...concept of force, and the trajectories are determined by geodesics. TG attributes gravitation to torsion, which accounts for gravitation by acting as a force. TG has already solved some old problems of gravitation (like the energy-momentum density of the gravitational field). The interest in TG has grown in the last few years. The book here proposed will be the first one dedicated exclusively to TG, and will include the foundations of the theory, as well as applications to specific problems to illustrate how the theory works.
Passive ankle dorsiflexion range of motion (DROM) measures have been identified as a risk factor for injury during landings. However, passive measurements might not be indicative of dynamic ankle ...movement, whereas a weightbearing ROM might be a better tool when evaluating movement. The purpose of this study was to investigate the relationship between weightbearing DROM and sagittal plane landing mechanics in a single leg drop jump task.
Seventy-three male athletes (22.1±3.9 years old, height 186.2±11 cm, and weight 100.2±21.8 kg) performed bilateral modified-lunge tasks and bilateral single leg drop jump landings while 3D kinematic data were collected. Hip, knee, and ankle joint angles were calculated at initial contact (IC) maximum knee flexion (MKF), and total excursion (TE) during a single leg drop jump landing.
No bilateral differences in DROM and single leg landing mechanics existed. Decreased ankle DROM was correlated to decreased ankle dorsiflexion at MKF (P=0.00) and TE (P=0.00) for both dominant and non-dominant limbs. Decreased ankle DROM was also correlated to decreased knee flexion at IC (P=0.00), MKF (P=0.00), and TE (P=0.1), for both dominant and non-dominant limbs. Ankle DROM correlated to hip flexion at MKF (r=0.25) and TE (r=0.30) in the dominant limb.
Restrictions in DROM may contribute to a stiff landing with less flexion at the ankle and knee. These findings may be useful in designing training programs aimed at increasing DROM in order to improve an athlete's landing mechanics and decrease risk of injury.
The Particle Finite Element Method (PFEM) is a Lagrangian finite element method with frequent remeshing, particularly suited for the simulation of fluid motions with evolving free surfaces, e.g., in ...the case of breaking waves or fluid–structure interactions with large displacements of the interaction surface. While the method has been successfully employed in a number of different engineering applications, there are several circumstances of practical interest where the Lagrangian nature of the method makes it difficult to enforce non-homogeneous boundary conditions. A novel mixed Lagrangian–Eulerian technique is proposed to the purpose of simplifying the imposition of this type of conditions with the PFEM. The method is simple to implement and computationally convenient, since only nodes on the boundary are considered Eulerian, while nodes inside the fluid body maintain their Lagrangian nature. A number of 2D and 3D examples, with analytical and numerical validations, confirm the excellent performance of the method.
By disserting on “Symmetry in Physical Laws” during one of his lectures, Richard P. Feynman asked: «Why is nature so nearly symmetrical?». He added: «No one has any idea why. The only thing we might ...suggest is something like this: There is a gate in Japan, a gate in Neiko, which is sometimes called by the Japanese the most beautiful gate in all Japan; it was built in a time when there was a great influence from Chinese art. This gate is very elaborate, with lots of gables and beautiful carving and lots of columns and dragon heads and princes carved into the pillars, and so on. But when one looks closely he sees that in the elaborate and complex design along one of the pillars, one of the small design elements is carved upside down; otherwise the thing is completely symmetrical. If one asks why this is, the story is that it was carved upside down so that the gods will not be jealous of the perfection of man. So they purposely put an error in there, so that the gods would not be jealous and get angry with human beings. We might like to turn the idea around and think that the true explanation of the near symmetry of nature is this: that God made the laws only nearly symmetrical so that we should not be jealous of His perfection!». In attempting to provide an answer to the Feynman’s question, the present paper show how one inevitably incurs a paradox.
Chronic sacroiliac (SI) joint-related low back pain (LBP) is a common, yet under-diagnosed and undertreated condition due to difficulties in accurate diagnosis and highly variable treatment ...practices. In patients with debilitating SI-related LBP for at least 6 months duration who have failed conservative management, arthrodesis is a viable option. The SImmetry(®) SI Joint Fusion System is a novel therapy for SI joint fusion, not just fixation, which utilizes a minimally invasive surgical approach, instrumented fixation for immediate stability, and joint preparation with bone grafting for a secure construct in the long term. The purpose of this report is to describe the minimally invasive SI Joint Fusion System, including patient selection criteria, implant characteristics, surgical technique, postoperative recovery, and biomechanical testing results. Advantages and limitations of this system will be discussed.
By observing through the microscope a biological structure at the different scale levels, it is possible to live an astonishing experience which leads the explorer to travel across hierarchically ...structured geometrical worlds where spaces and paths are established by forms of unexpected strictness and symmetrical constructions conceal nested architectures which create self-similar universes evoking Koch's fractals or three-dimensional versions of Mandelbrot sets. The finding – surprising and consolatory at the same time – that living matter can somehow exhibit symmetries and levels of order one generally (and only) associates to inorganic crystals, de facto undermines the foundations of some dichotomous categories on which both Science and Philosophy are based, consequently making fluid the boundaries between organic and inorganic, artificial and natural and – at the end – between life and death. The Life – at the macro- and micro-scopic eye – is available. It is geometrical disposition, conformal symmetry, solution and result. But Life, where that eye (and its extents) is slotted, is meta-order, at most World as energy and kinematic laps, anyway para-logical priority, logical noise, paradox of the tangible and of the material. So, Science and Philosophy become comment and/or protest of the human mind in front of a “There Is”, and in this blame game between meta-bio-logical prius and historical preemption, any result of the human mind is also a result of the Life, of physical and chemical auto-organization which allows the Life itself. Not only methodological explosion of dichotomies as Natural/Artificial, Organic/Inorganic – the practice or the break of the dichotomy is however an existential demand of the Logos – rather secret horizon required by human livings, mass-produced mirrors of self-references and semantic codes. Symmetries and violations of symmetries in piles of Selfies to post on social networks of Science and Philosophy, on hold of feedback loops. So, Symmetry is not necessarily the background or the foreseeing, and the Asymmetry is not necessarily infraction and fancy.
Una prueba de evaluación oral de una lengua extranjera es un contexto donde está presente un discurso institucional, con un marcado fin transaccional. Se suceden temas o tareas, previstos por los ...diseñadores de la prueba de evaluación, que definen la secuencia de la prueba. En el estudio que presentamos, analizamos el control del tema que ejercería la examinanda sobre las tareas y los temas previstos (que estará relacionado con la duración y el mantenimiento de los temas, así como con la introducción de subtemas) y la colaboración entre examinadora y examinanda. Los resultados pueden ofrecer pistas para dar más cabida al fin interpersonal con mayor simetría entre los participantes y adecuar así las pruebas.
This paper develops the study of the geometrical characteristics of the class of frames of reference associated with the two well known sets of coordinates: Levi-Civita's curvature coordinates and ...gaussian polar coordinates. In particular, through the separate invariant formulation of the initial data problem and of the restricted evolution problem, the analysis is applied to a spherically symmetric perfect fluid, whose stream lines coincide with those of the above mentioned class of frames.
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