1,951,388 research outputs found

    Coherent Acceleration of Material Wavepackets

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    We study the quantum dynamics of a material wavepacket bouncing off a modulated atomic mirror in the presence of a gravitational field. We find the occurrence of coherent accelerated dynamics for atoms. The acceleration takes place for certain initial phase space data and within specific windows of modulation strengths. The realization of the proposed acceleration scheme is within the range of present day experimental possibilities.Comment: 6 pages, 3 figures, NASA "Quantum-to-Cosmos" conference proceedings to be published in IJMP

    Ladder proof of nonlocality for two spin-half particles revisited

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    In this paper we extend the ladder proof of nonlocality without inequalities for two spin-half particles given by Boschi et al [PRL 79, 2755 (1997)] to the case in which the measurement settings of the apparatus measuring one of the particles are different from the measurement settings of the apparatus measuring the other particle. It is shown that, in any case, the proportion of particle pairs for which the contradiction with local realism goes through is maximized when the measurement settings are the same for each apparatus. Also we write down a Bell inequality for the experiment in question which is violated by quantum mechanics by an amount which is twice as much as the amount by which quantum mechanics violates the Bell inequality considered in the above paper by Boschi et al.Comment: LaTeX, 7 pages, 1 figure, journal versio

    Parabolic reflector horn feed with spillover correction Patent

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    Device for improving efficiency of parabolic reflector horn for linearly or circularly polarized wave

    Augmenting human memory using personal lifelogs

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    Memory is a key human facility to support life activities, including social interactions, life management and problem solving. Unfortunately, our memory is not perfect. Normal individuals will have occasional memory problems which can be frustrating, while those with memory impairments can often experience a greatly reduced quality of life. Augmenting memory has the potential to make normal individuals more effective, and those with significant memory problems to have a higher general quality of life. Current technologies are now making it possible to automatically capture and store daily life experiences over an extended period, potentially even over a lifetime. This type of data collection, often referred to as a personal life log (PLL), can include data such as continuously captured pictures or videos from a first person perspective, scanned copies of archival material such as books, electronic documents read or created, and emails and SMS messages sent and received, along with context data of time of capture and access and location via GPS sensors. PLLs offer the potential for memory augmentation. Existing work on PLLs has focused on the technologies of data capture and retrieval, but little work has been done to explore how these captured data and retrieval techniques can be applied to actual use by normal people in supporting their memory. In this paper, we explore the needs for augmenting human memory from normal people based on the psychology literature on mechanisms about memory problems, and discuss the possible functions that PLLs can provide to support these memory augmentation needs. Based on this, we also suggest guidelines for data for capture, retrieval needs and computer-based interface design. Finally we introduce our work-in-process prototype PLL search system in the iCLIPS project to give an example of augmenting human memory with PLLs and computer based interfaces

    Development and application of a three dimensional numerical model for predicting pollutant and sediment transport using an Eulerian-Lagrangian marker particle technique

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    A computer coded Lagrangian marker particle in Eulerian finite difference cell solution to the three dimensional incompressible mass transport equation, Water Advective Particle in Cell Technique, WAPIC, was developed, verified against analytic solutions, and subsequently applied in the prediction of long term transport of a suspended sediment cloud resulting from an instantaneous dredge spoil release. Numerical results from WAPIC were verified against analytic solutions to the three dimensional incompressible mass transport equation for turbulent diffusion and advection of Gaussian dye releases in unbounded uniform and uniformly sheared uni-directional flow, and for steady-uniform plug channel flow. WAPIC was utilized to simulate an analytic solution for non-equilibrium sediment dropout from an initially vertically uniform particle distribution in one dimensional turbulent channel flow

    Acceleration of bouncing balls in external fields

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    We introduce two models, the Fermi-Ulam model in an external field and a one dimensional system of bouncing balls in an external field above a periodically oscillating plate. For both models we investigate the possibility of unbounded motion. In a special case the two models are equivalent

    Towards Sustainable Development of Small-Scale Fisheries in the Philippines: Experiences and Lessons Learned from Eight Regional Sites

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    The focus of this paper is on the governance of small-scale or municipal fisheries in the Philippines in light of the critical role they play in the livelihoods of coastal communities and in the nation as a whole. The information and insights presented in this lessons learned brief derive from the project entitled Strengthening Governance and Sustainability of Small-Scale Fisheries Management in the Philippines: An Ecosystem Approach. The project was funded principally by the Department of Agriculture's Bureau of Agricultural Research (DA-BAR), and implemented from 2008 to 2011 by WorldFish in collaboration with the Department of Science and Technology (DOST) and selected partners. The underlying project's goal was to 'strengthen governance and sustainability of small-scale fisheries management in the Philippines.' There were a variety of objectives spread across two project phases but the primary objectives relevant to this brief include: (1) identifying issues at project sites and assessing potential for an ecosystem based approach to fisheries management, and (2) assessing current fisheries management practices at different levels of governance and identifying best practices. The purposes of this paper are twofold. First, it aims to provide brief highlights of the project findings; second, it aims to present the lessons learned in project implementation covering substantive sectoral concerns as well as methodological issues. It wraps up with some strategic directions that need to be undertaken to reverse the deteriorating conditions of small-scale fisheries (SSF) while at the same time promoting their sustainable development
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