4,552 research outputs found
Extending Hamiltonian Operators to Get Bi-Hamiltonian Coupled KdV Systems
An analysis of extension of Hamiltonian operators from lower order to higher
order of matrix paves a way for constructing Hamiltonian pairs which may result
in hereditary operators. Based on a specific choice of Hamiltonian operators of
lower order, new local bi-Hamiltonian coupled KdV systems are proposed. As a
consequence of bi-Hamiltonian structure, they all possess infinitely many
symmetries and infinitely many conserved densities.Comment: 13 pages, late
Myogenic transcription factors regulate pro-metastatic miR-182
Approximately thirty percent of patients with soft-tissue sarcoma die from pulmonary metastases. The mechanisms that drive sarcoma metastasis are not well understood. Recently, we identified miR-182 as a driver of sarcoma metastasis in a primary mouse model of soft-tissue sarcoma. We also observed elevated miR-182 in a subset of primary human sarcomas that metastasized to the lungs. Here, we show that myogenic differentiation factors regulate miR-182 levels to contribute to metastasis in mouse models. We find that MyoD directly binds the miR-182 promoter to increase miR-182 expression. Furthermore, mechanistic studies revealed that Pax7 can promote sarcoma metastasis in vivo through MyoD-dependent regulation of pro-metastatic miR-182. Taken together, these results suggest that sarcoma metastasis can be partially controlled through Pax7/MyoD-dependent activation of miR-182 and provide insight into the role that myogenic transcription factors play in sarcoma progression
PMH41 REDUCTION IN LONG-ACTING BENZODIAZEPINE THERAPY AND ASSOCIATED FRACTURES IN ELDERLY MEDICAID PATIENTS
PAR19: IMPACT OF THE ADDITION OF SALMETEROL TO THE TREATMENT OF ASTHMA PATIENTS IN A MEDICAID FEE-FOR-SERVICE POPULATION
Coupled KdV equations of Hirota-Satsuma type
It is shown that the system of two coupled Korteweg-de Vries equations passes
the Painlev\'e test for integrability in nine distinct cases of its
coefficients. The integrability of eight cases is verified by direct
construction of Lax pairs, whereas for one case it remains unknown
Robot Mapping and Localisation for Feature Sparse Water Pipes Using Voids as Landmarks
Robotic systems for water pipe inspection do not generally include navigation components for mapping the pipe network and locating damage. Such navigation systems would be highly advantageous for water companies because it would allow them to more effectively target maintenance and reduce costs. In water pipes, a major challenge for robot navigation is feature sparsity. In order to address this problem, a novel approach for robot navigation in water pipes is developed here, which uses a new type of landmark feature - voids outside the pipe wall, sensed by ultrasonic scanning. The method was successfully demonstrated in a laboratory environment and showed for the first time the potential of using voids for robot navigation in water pipes
Integrable KdV Systems: Recursion Operators of Degree Four
The recursion operator and bi-Hamiltonian formulation of the Drinfeld-
Sokolov system are givenComment: Latex File, to be published in Physucs Letters
Robot mapping and localisation in metal water pipes using hydrophone induced vibration and map alignment by dynamic time warping
Water is a highly valuable resource so asset management of associated infrastructure is of critical importance. Water distribution pipe networks are usually buried, and so are difficult to access. Robots are therefore appealing for performing inspection and detecting damage to target repairs. However, robot mapping and localisation of buried water pipes has not been widely investigated to date, and is challenging because pipes tend to be relatively featureless. In this paper we propose a mapping and localisation algorithm for metal water pipes with two key novelties: the development of a new type of map based on hydrophone induced vibration signals of metal pipes, and a mapping algorithm based on spatial warping and averaging of dead reckoning signals used to calibrate the map (using dynamic time warping). Localisation is performed using both terrain-based extended Kalman filtering and also particle filtering. We successfully demonstrate and evaluate the approach on a combination of experimental and simulation data, showing improved localisation compared to dead reckoning
PipeSLAM: Simultaneous Localisation and Mapping in Feature Sparse Water Pipes using the Rao-Blackwellised Particle Filter
Water, a valuable resource, is usually distributed through urban environments by buried pipes. These pipes are difficult to access for inspection, maintenance and repair. This makes in-pipe robots an appealing technology for inspecting water pipes and localising damage prior to repair from above ground. Accurate localisation of damage is of critical importance because of the costs associated with excavating roads, disrupting traffic and disrupting the water supply. The problem is that pipes tend to be relatively featureless making robot localisation a challenging problem. In this paper we propose a novel simultaneous localisation and mapping (SLAM) algorithm for metal water pipes. The approach we take is to excite pipe vibration with a hydrophone (sound induced vibration), which leads to a map of pipe vibration amplitude over space. We then develop a SLAM algorithm that makes use of this new type of map, where the estimation method is based on the Rao-Blackwellised particle filter (RBPF), termed PipeSLAM. The approach is also suited to SLAM in plastic water pipes using a similar type of map derived from ultrasonic sensing. We successfully demonstrate the feasibility of the approach using a combination of experimental and simulation data
Non-Markovian Dynamics of Spin Squeezing
We evaluate the spin squeezing dynamics of N independent spin-1/2 particles
with exchange symmetry. Each spin interacts with its own reservoir, and the
reservoirs are independently and identical. The spin squeezing parameter is
analytically calculated with different kinds of decoherence. The spin squeezing
property vanishes with evolution time under the Markovian decoherence. Whereas
coupled to the non-Markovian decoherence channels, the spin squeezing property
collapses and revives with time. As spin squeezing can be regarded as a witness
of multipartite entanglement, thus our scheme shows the collapse and revival of
multipartite entanglement under non-Markovian decoherence.Comment: 13 pages, 7 figure
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