Spacetime structure and vacuum entanglement

We study the role that both vacuum fluctuations and vacuum entanglement of a scalar field play in identifying the spacetime topology, which is not prescribed from first principles---neither in general relativity or quantum gravity. We analyze how the entanglement and observable correlations acquired between two particle detectors are sensitive to the spatial topology of spacetime. We examine the detector's time evolution to all orders in perturbation theory and then study the phenomenon of vacuum entanglement harvesting in Minkowski spacetime and two flat topologically distinct spacetimes constructed from identifications of the Minkowski space. We show that, for instance, if the spatial topology induces a preferred direction, this direction may be inferred from the dependence of correlations between the two detectors on their orientation. We therefore show that vacuum fluctuations and vacuum entanglement harvesting makes it, in principle, possible to distinguish spacetimes with identical local geometry that differ only in their topology

Volunteer Development in 4-H: Constructivist Considerations to Improve Youth Science Literacy in Urban Areas

The 4-H Youth Development Program can play an important role in targeting improved science literacy among urban youth in the U. S. However, 4-H volunteers must be trained effectively in order to be competent in their roles as science educators, and existing methods of volunteer training in urban areas are inadequate. Lesson study, a professional development model for educators that uses a constructivist approach to learning, is a viable option. Lesson study occurs within the context of the specific learning setting, takes place incrementally over extended periods of time, and has been shown to be effective

RR Lyrae in XSTPS: The halo density profile in the North Galactic Cap

We present a catalog of RR Lyrae stars (RRLs) observed by the Xuyi Schmidt Telescope Photometric Survey (XDSS). The area we consider is located in the North Galactic Cap, covering 376.75 sq deg at RA $\approx$ 150 deg and Dec $\approx$ 27 deg down to a magnitude limit of i $\approx$ 19. Using the variability information afforded by the multi-epoch nature of our XDSS data, combined with colors from the Sloan Digital Sky Survey, we are able to identify candidate RRLs. We find 318 candidates, derive distances to them and estimate the detection efficiency. The majority of our candidates have more than 12 observations and for these we are able to calculate periods. These also allows us to estimate our contamination level, which we predict is between 30% to 40%. Finally we use the sample to probe the halo density profile in the 9-49 kpc range and find that it can be well fitted by a double power law. We find good agreement between this model and the models derived for the South Galactic Cap using the Watkins et al. (2009) and Sesar et al. (2010) RRL data-sets, after accounting for possible contamination in our data-set from Sagittarius stream members. We consider non-spherical double power law models of the halo density profile and again find agreement with literature data-sets, although we have limited power to constrain the flattening due to our small survey area. Much tighter constraints will be placed by current and future wide-area surveys, most notably ESA's astrometric Gaia mission. Our analysis demonstrates that surveys with a limited number of epochs can effectively be mined for RRLs. Our complete sample is provided as accompanying online material.Comment: 14 pages, ApJ (in press

Training 4-H Teen Facilitators in Inquiry-Based Science Methods: The Evaluation of a Step-Up Incremental Training Model

A Step-Up Incremental Training Model for teen curriculum facilitators implementing inquiry-based science activities was designed and evaluated. This model involves a sequence of three training workshops that alternate with curriculum implementations. The model was evaluated using data from focus group interviews, surveys, and direct observations. Key elements in the model\u27s design include: workshop organization; introductory session; multiple increments; effective modeling and practice; safe environment for reflection and review. The teens trained during the development of this model were effective in implementing curriculum activities with young children. The authors believe that this method would be transferable to other teen-led Extension programs

A Model for Recruiting and Training Youth Development Volunteers in Urban Areas

A model for recruiting and training volunteers for 4-H Youth Development Programs in urban areas was designed and evaluated. Utilizing a formal course at a community college to recruit and train volunteers, the model was effective in developing and enhancing their skills. As part of their course requirements, volunteers applied their skills by implementing a science literacy program with elementary-age children in after-school settings. Their efforts were effective; participating children\u27s science process skills showed significant improvements. Academic and community service credit served as rewards for volunteers\u27 participation

Dependence of Maximum Trappable Field on Superconducting Nb3Sn Cylinder Wall Thickness

Uniform dipole magnetic fields from 1.9 to 22.4 kOe were permanently trapped, with high fidelity to the original field, transversely to the axes of hollow Nb3Sn superconducting cylinders. These cylinders were constructed by helically wrapping multiple layers of superconducting ribbon around a mandrel. This is the highest field yet trapped, the first time trapping has been reported in such helically wound taped cylinders, and the first time the maximum trappable field has been experimentally determined as a function of cylinder wall thickness.Comment: 8 pages, 4 figures, 1 table. PACS numbers: 74.60.Ge, 74.70.Ps, 41.10.Fs, 85.25.+

A fault-tolerant multiprocessor architecture for aircraft, volume 1

A fault-tolerant multiprocessor architecture is reported. This architecture, together with a comprehensive information system architecture, has important potential for future aircraft applications. A preliminary definition and assessment of a suitable multiprocessor architecture for such applications is developed

Polarization effects in tau production by neutrino

We studied polarization effects in tau production by neutrino-nucleon scattering. Quasi-elastic scattering, $Delta$ resonance production and deep inelastic scattering processes are taken into account for the CERN-to-Gran Sasso projects. We show that the tau produced by neutrino has high degree of polarization, and its spin direction depends non-trivially on the energy and the scattering angle of tau in the laboratory frame.Comment: 6 pages, 5 eps figures, espcrc2.sty; Proceedings of the 3rd International Workshop on Neutrino-Nucleus Interactions in the Few GeV Region (NuInt04), March 17-21, 2004, Gran Sasso, Italy; minor changes, typos in Eq. (6) correcte

The “Space Between”: Situated Professional Development to Enhance 4-H Educators’ Pedagogical Design Capacity for Effective Curriculum Enactment

Curricula are planned and written by curriculum developers; they serve as instructional guides for educators. Educators make adaptations to written curricula to meet learners’ needs and achieve intended learning outcomes. The efficacy of curriculum adaptations is enhanced when educators have a high pedagogical design capacity, which can be improved through effective professional development. Lesson study is a model of situated professional development centered around ongoing improvement of curriculum enactment. Educators work collaboratively to make curriculum modifications and data-driven decisions to improve their teaching practices. Lesson study occurs at regular intervals over an extended duration