1,325 research outputs found

    Fractional Quantum Mechanics and Levy Path Integrals

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    The fractional quantum and statistical mechanics have been developed via new path integrals approach.Comment: 8 pages, added references for section

    Electromagnetic Position Sensing and Force Feedback for a Magnetic Stylus with an Interactive Display

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    This letter describes the design, implementation, validation, and demonstration of an electromagnetic system that can be incorporated into a graphical display to provide computer-controlled planar feedback forces on the tip of a stylus or fingertip-mounted magnet held near the display surface, according to the magnet position and virtual fixtures implemented in software. An array of magnetometer sensors is used to detect the position of the magnet, while a pair of box-shaped coils behind the display produces feedback forces on the stylus parallel to the plane of the display. Electromagnetic analysis for the system design is presented and system implementation is described. Validation results are given for force generation within a 100 mm × 100 mm area and force interaction with a virtual obstacle is demonstrated

    What is the Health Impact of Day Care Attendance on Infants and Preschoolers?

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    The impact of various child care arrangements on the health of infants and preschool children is not known in any systematic way, yet by 1990 more than 10 million of these children may be receiving their care in day care facilities (1). Concerns over the health of these children and health practices within day care facilities have already led some States to place regulation of day care facilities under the jurisdiction of the department of health (2,3), and others are presently considering such legislation. In addition, the American Academy of Pediatrics has recently published Health in Day Care, a manual for health professionals who are being increasingly called upon for advice concerning health issues related to children in day care facilities (4)

    Measurement of CP Violation at the Υ(4S)\Upsilon(4S) without Time Ordering or Δt\Delta t

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    I derive the expressions for the CP-violating asymmetry arising from interference between mixed and direct decays in the Upsilon(4S) system, for the case in which only one of the B decay times is observed, integrating over the decay time of the other B. I observe that neither the difference of the decay times Delta t, nor even their time-ordering, need be detected. A technique for measurement of the CP-violating weak decay parameter sin(2beta) is described which exploits this observation.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

    Miniature fiber-optic force sensor based on low-coherence Fabry-Pérot interferometry for vitreoretinal microsurgery

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    During vitreoretinal surgery, the surgeon manipulates retinal tissue with tool-to-tissue interaction forces below the human sensory threshold. A force sensor (FS) integrated with conventional surgical tools may significantly improve the surgery outcome by providing tactile feedback to the surgeon. We designed and built a surgical tool integrated with a miniature FS with an outer diameter smaller than 1 mm for vitreoretinal surgery based on low-coherence Fabry–Pérot (FP) interferometry. The force sensing elements are located at the tool tip which is in direct contact with tissue during surgery and the FP cavity length is interrogated by a fiber-optic common-path phase-sensitive optical coherence tomography (OCT) system. We have calibrated the FS's response to axial and lateral forces and conducted experiments to verify that our FS can simultaneously measure both axial and lateral force components

    Medical image computing and computer-aided medical interventions applied to soft tissues. Work in progress in urology

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    Until recently, Computer-Aided Medical Interventions (CAMI) and Medical Robotics have focused on rigid and non deformable anatomical structures. Nowadays, special attention is paid to soft tissues, raising complex issues due to their mobility and deformation. Mini-invasive digestive surgery was probably one of the first fields where soft tissues were handled through the development of simulators, tracking of anatomical structures and specific assistance robots. However, other clinical domains, for instance urology, are concerned. Indeed, laparoscopic surgery, new tumour destruction techniques (e.g. HIFU, radiofrequency, or cryoablation), increasingly early detection of cancer, and use of interventional and diagnostic imaging modalities, recently opened new challenges to the urologist and scientists involved in CAMI. This resulted in the last five years in a very significant increase of research and developments of computer-aided urology systems. In this paper, we propose a description of the main problems related to computer-aided diagnostic and therapy of soft tissues and give a survey of the different types of assistance offered to the urologist: robotization, image fusion, surgical navigation. Both research projects and operational industrial systems are discussed

    Electromagnetic Position Sensing and Force Feedback for a Magnetic Stylus with an Interactive Display

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    This letter describes the design, implementation, validation, and demonstration of an electromagnetic system that can be incorporated into a graphical display to provide computer-controlled planar feedback forces on the tip of a stylus or fingertip-mounted magnet held near the display surface, according to the magnet position and virtual fixtures implemented in software. An array of magnetometer sensors is used to detect the position of the magnet, while a pair of box-shaped coils behind the display produces feedback forces on the stylus parallel to the plane of the display. Electromagnetic analysis for the system design is presented and system implementation is described. Validation results are given for force generation within a 100 mm × 100 mm area and force interaction with a virtual obstacle is demonstrated

    Exclusive and Semi-Inclusive B Decays Based on \hspace{0.3cm} b →\rightarrow s \hspace{0.01cm}ηc\eta_c \hspace{0.3cm} Transition

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    We calculate the semi-inclusive processes B →Xsηc\rightarrow X_{s} \eta_c and relate it to B →Xsψ\rightarrow X_{s} \psi in next to leading order QCD, and show how it can be used to determine an accurate value of fηcf_{\eta_{c}}. The exclusive modes B →\rightarrow Kηc\eta_c and B →\rightarrow Kψ\psi also yield similar results, whereas B →\rightarrow K∗ηc^*\eta_c and B →\rightarrow K∗ψ^*\psi can provide valuable information on hadronic form factors. We also estimate the branching ratios and the ratios of exclusive to inclusive decay modes dominated by b \rightarrow s\e.Comment: 12 pages LATEX, (used new data on B decays, give determination of fηcf_{\eta_c} and more models
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