187 research outputs found

    Synchro-Betatron Stop-Bands due to a Single Crab Cavity

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    We analyze the stop-band due to crab cavities for horizontal tunes that are either close to integers or close to half integers. The latter case is relevant for today's electron/positron colliders. We compare this stop-band to that created by dispersion in an accelerating cavity and show that a single typical crab cavity creates larger stop-bands than a typical dispersion at an accelerating cavity. We furthermore analyze whether it is beneficial to place the crab cavity at a position where the dispersion and its slope vanish. We find that this choice is worth while if the horizontal tune is close to a half integer, but not if it is close to an integer. Furthermore we find that stop-bands can be avoided when the horizontal tune is located at a favorable side of the integer or the half integer. While we are here concerned with the installation of a single crab cavity in a storage ring, we show that the stop-bands can be weakened, although not eliminated, significantly when two crab cavities per ring are chosen suitably.Comment: 7 pages, 9 figure

    Study to assess the importance of errors introduced by applying NOAA 6 and NOAA 7 AVHRR data as an estimator of vegetative vigor: Feasibility study of data normalization

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    The use of NOAA AVHRR data to map and monitor vegetation types and conditions in near real-time can be enhanced by using a portion of each GAC image that is larger than the central 25% now considered. Enlargement of the cloud free image data set can permit development of a series of algorithms for correcting imagery for ground reflectance and for atmospheric scattering anisotropy within certain accuracy limits. Empirical correction algorithms used to normalize digital radiance or VIN data must contain factors for growth stage and for instrument spectral response. While it is not possible to correct for random fluctuations in target radiance, it is possible to estimate the necessary radiance difference between targets in order to provide target discrimination and quantification within predetermined limits of accuracy. A major difficulty lies in the lack of documentation of preprocessing algorithms used on AVHRR digital data

    Analytical Estimation of the Beam-Beam Interaction Limited Dynamic Apertures and Lifetimes in e^+e^- Circular Colliders

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    Physically speaking, the delta function like beam-beam nonlinear forces at interaction points (IPs) act as a sum of delta function nonlinear multipoles. By applying the general theory established in ref. 1, in this paper we investigate analytically the beam-beam interaction limited dynamic apertures and the corresponding beam lifetimes for both the round and the flat beams. Relations between the beam-beam limited beam lifetimes and the beam-beam tune shifts are established, which show clearly why experimentally one has always a maximum beam-beam tune shift, \xi_{y, max}, around 0.045 for e-^+e$^- circular colliders, and why one can use round beams to double this value approximately. Comparisons with some machine parameters are given. Finally, we discuss the mechanism of the luminosity reduction due to a definite collision crossing angle.Comment: 25 page

    Demonstration of angular anisotropy in the output of Thematic Mapper

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    There is a dependence of TM output (proportional to scene radiance in a manner which will be discussed) upon season, upon cover type and upon view angle. The existence of a significant systematic variation across uniform scenes in p-type (radiometrically and geometrically pre-processed) data is demonstrated. Present pre-processing does remove the effects and the problem must be addressed because the effects are large. While this is in no way attributable to any shortcomings in the thematic mapper, it is an effect which is sufficiently important to warrant more study, with a view to developing suitable pre-processing correction algorithms

    Against the Margins : Mark Z. Danielewski's House of Leaves and the Persistence of Print

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    Mark Z. Danielewski’s novel, House of Leaves, is a narratively complex and typographically experimental text that asserts the importance of print books in a digital world. This paper argues that, while its production mingled both analog and digital technologies, it remains steadfastly material to claim the distinctive capabilities of print. Yet, despite this material manifestation, House of Leaves launches a more nuanced debate between digital and print technology within the plot of the novel itself. The novel conscripts the reader into the conversation and demands recognition of the precariousness of print, which is always haunted by a threatening digital presence.Wetensch. publicati

    Relationship Between Sensory Integration and Occupational Participation for School-Aged Children

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    Given the wide-spread use of sensory integration intervention for the pediatric population in occupational therapy practice, it is necessary to explore the connection between sensory integration and children’s participation in daily occupations. Although there is a wide breadth of knowledge examining the impact of sensory integration intervention, there is currently a gap in the literature establishing the underlying relationship between sensory integration and children’s occupational participation. This study recruited 22 children, ages 5-12 to examine the relationship between sensory integration and occupational participation by utilizing two parent report measures: Sensory Processing Measure (SPM) and Participation & Environment Measure- Children and Youth (PEM-CY). Our findings suggest there is a moderate negative correlation between sensory processing and occupational participation in the home setting; therefore, the less sensory dysfunction a child has, the more they were found to participate in occupations

    Dependence of the Luminosity on Various Machine Parameters and Their Optimization at PETRA

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    Penetration of the Field of a Bunched Beam through a Ceramic Vacuum Chamber with Metallic Coating

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    E-Zn inelastic scattering at 80 eV

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    © Published under licence by IOP Publishing Ltd. Stokes and Electron Impact Coherence Parameters (EICPs) for electronic excitation of 41P1 state of zinc atoms have been measured for incident electron energy of 80 eV. The experimental data are presented together with Convergent Close Coupling (CCC) theoretical predictions. Our results are compared with recently published Relativistic Distorted-Wave Approximation (RDWA) calculations
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