23 research outputs found

    Entanglement in quantum computers described by the XXZ model with defects

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    We investigate how to generate maximally entangled states in systems characterized by the Hamiltonian of the XXZ model with defects. Some proposed quantum computers are described by such model. We show how the defects can be used to obtain EPR states and W states when one or two excitations are considered.Comment: 4 pages, 1 figur

    A system of ODEs for a Perturbation of a Minimal Mass Soliton

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    We study soliton solutions to a nonlinear Schrodinger equation with a saturated nonlinearity. Such nonlinearities are known to possess minimal mass soliton solutions. We consider a small perturbation of a minimal mass soliton, and identify a system of ODEs similar to those from Comech and Pelinovsky (2003), which model the behavior of the perturbation for short times. We then provide numerical evidence that under this system of ODEs there are two possible dynamical outcomes, which is in accord with the conclusions of Pelinovsky, Afanasjev, and Kivshar (1996). For initial data which supports a soliton structure, a generic initial perturbation oscillates around the stable family of solitons. For initial data which is expected to disperse, the finite dimensional dynamics follow the unstable portion of the soliton curve.Comment: Minor edit

    Analysis of shared heritability in common disorders of the brain

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    Paroxysmal Cerebral Disorder

    Em prol do sacrifício do isolamento: lepra e filantropia na Argentina e no Brasil, 1930-1946

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    Immunohistochemical detection of neuromodulators in the gastrointestinal tract of turbot, Psetta maxima (L.)

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    Post-mortem specimens taken from the antebrachial and brachial fasciae of 20 upper limbs were studied by histological and immunohistochemical staining in order to evaluate collagen fibre bundle arrangement, the presence of elastic fibres, and the density of innervation in deep muscular fascia. The study demonstrated that the fasciae are formed of numerous layers of undulating collagen fibre bundles. In each layer, the bundles are parallel to each other, whereas adjacent layers show different orientations. Each layer is separated from the adjacent one by a thin layer of adipose tissue, like plywood. Many elastic fibres and a variety of both free and encapsulated nerve endings, especially Ruffini and Pacini corpuscles, are also present, suggesting a proprioceptive capacity of the deep fascia. Thanks to the undulating collagen fibre bundles and elastic fibres, the fasciae can adapt to stretching, but this is only possible within certain limits, beyond which nerve terminations are activated by stretching. This mechanism allows a son of "gate control" on the normal activation of intrafascial receptors. The capacity of the various collagen layers to slide over each other may be altered in cases of over-use syndrome, trauma or surgery. In such cases, the amortising mechanism of the fascia on the nervous terminations is lost, causing incorrect paradoxical activation of nerve receptors within the fascia, resulting in the propagation of a nociceptive signal even in situations of normal physiological stretch. At the same time, the layered collagen fibres allow transmission of tension according to the various lines of force. This structure of the muscular fascia guarantees perceptive and directional continuity along a particular myokinetic chain, acting like a transmission belt between two adjacent joints and also between synergic muscle groups

    The parasitic travel of Margaritifera margaritifera in Atlantic salmon gills: from glochidium to post-larva

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    The larval development of the endangered freshwater mussel Margaritifera margaritifera (L.) represents one of the most unique parasitism among naiads, in which larva parasite the fish gills for several months. Despite the importance of this parasitic phase to successfully culture the freshwater mussel, the larval morphogenesis remains understudied. To describe the parasitic larval development and metamorphosis, Atlantic salmon (Salmo salar L.) were exposed to glochidia, sampled periodically to visualize the gills by stereomicroscopy and light microscopy and results were summarized throughout three developmental stages. Once attached to the fish gills, glochidia changed their morphology within the first days and acquired an intermediate stage termed mushroom larva due to the presence of the mushroom body and the zip membrane, both structures are transitory and distinctive of this long-lasting parasitism. The zip membrane, located at the valve cleft, may play a unique role in the isolation and acquisition of non-particulate nutrients from the fish, while the mushroom body of the mantle accumulates abundant intracytoplasmic lipid droplets. After 200 days, a successful metamorphosis was evidenced by the formation of a complete set of post-larval organs, pointing to the acquisition of different functionality, which will be essential for the settlement and deposit-feeding into the riverbed. Among the post-larval organs, the byssal complex of the post-larval foot was described for the first time at the end of the parasitic stage of naiads. In conclusion, this study provides an overview of the larval morphogenesis of M. margaritifera, from glochidium to post-larva, essential for understanding the parasitic interaction between the freshwater mussel larva and the fish host. Moreover, the morphological techniques and the hallmarks described might be applicable to optimize and monitor the larval developmental status during one of the most critical stages of the captive breeding programmes of endangered freshwater mussels
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