Influence of Basis-set Size on the X\u3csup\u3e2\u3c/sup\u3eΣ\u3csup\u3e+\u3c/sup\u3e\u3csub\u3e1/2\u3c/sub\u3e, A\u3csup\u3e2\u3c/sup\u3eΠ\u3csub\u3e1/2\u3c/sub\u3e, A\u3csup\u3e2\u3c/sup\u3eΠ\u3csub\u3e3/2\u3c/sub\u3e, and B\u3csup\u3e2\u3c/sup\u3eΣ\u3csub\u3e1/2\u3c/sub\u3e potential-energy curves, A\u3csup\u3e2\u3c/sup\u3eΠ\u3csub\u3e3/2\u3c/sub\u3e 2 vibrational energies, and D\u3csub\u3e1\u3c/sub\u3e and D\u3csub\u3e2\u3c/sub\u3e line shapes of Rb+He

The X 2 Σ + 1 / 2 , A 2 Π 1 / 2 , A 2 Π 3 / 2 , and B 2 Σ + 1 / 2 potential-energy curves for Rb+He are computed at the spin-orbit multireference configuration interaction level of theory using a hierarchy of Gaussian basis sets at the double-zeta (DZ), triple-zeta (TZ), and quadruple-zeta (QZ) levels of valence quality. Counterpoise and Davidson-Silver corrections are employed to remove basis-set superposition error and ameliorate size-consistency error. An extrapolation is performed to obtain a final set of potential-energy curves in the complete basis-set (CBS) limit. This yields four sets of systematically improved X 2 Σ + 1 / 2 , A 2 Π 1 / 2 , A 2 Π 3 / 2 , and B 2 Σ + 1 / 2 potential-energy curves that are used to compute the A 2 Π 3 / 2 bound vibrational energies, the position of the D 2 blue satellite peak, and the D 1 and D 2 pressure broadening and shifting coefficients, at the DZ, TZ, QZ, and CBS levels. Results are compared with previous calculations and experimental observation

Circles in the Sky: Finding Topology with the Microwave Background Radiation

If the universe is finite and smaller than the distance to the surface of last scatter, then the signature of the topology of the universe is writ large on the microwave background sky. We show that the microwave background will be identified at the intersections of the surface of last scattering as seen by different ``copies'' of the observer. Since the surface of last scattering is a two-sphere, these intersections will be circles, regardless of the background geometry or topology. We therefore propose a statistic that is sensitive to all small, locally homogeneous topologies. Here, small means that the distance to the surface of last scatter is smaller than the ``topology scale'' of the universe.Comment: 14 pages, 10 figures, IOP format. This paper is a direct descendant of gr-qc/9602039. To appear in a special proceedings issue of Class. Quant. Grav. covering the Cleveland Topology & Cosmology Worksho

Developing Conceptual and Methodological Foundations in Community Engagement

We describe the efforts of two related undergraduate projects to promote lasting social change in marginalized communities in the Dominican Republic and Nicaragua. The projects represent a test of the premise that undergraduate projects can engage academically based strategies and transcend good intentions to achieve effective community partnerships to improve health and health care. The projects proceed from a perspective and theory of marginalization and its consequences. Specifically, marginalization undermines individual and collective capacity to meet basic needs and efforts to thrive. Through strengthening social infrastructure, communities can overcome the effects of marginalization. Project work begins with annual medical clinics and, with the permission of community residents, team members conduct ethnographic descriptions of the communities and their health and health care concerns and resources. We use social network analysis (SNA) and geographic information system (GIS) techniques to describe social infrastructure. Working from those foundations, both projects have enabled increased social infrastructure. To date, we have observed increased communication among community residents, facilitated the development of community-endorsed five-year plans, and established partnerships with regional and international groups

EVA-SCRAM operations

This paper wrestles with the on-orbit operational challenges introduced by the proposed Space Construction, Repair, and Maintenance (SCRAM) tool kit for Extra-Vehicular Activity (EVA). SCRAM undertakes a new challenging series of on-orbit tasks in support of the near-term Hubble Space Telescope, Extended Duration Orbiter, Long Duration Orbiter, Space Station Freedom, other orbital platforms, and even the future manned Lunar/Mars missions. These new EVA tasks involve welding, brazing, cutting, coating, heat-treating, and cleaning operations. Anticipated near-term EVA-SCRAM applications include construction of fluid lines and structural members, repair of punctures by orbital debris, refurbishment of surfaces eroded by atomic oxygen, and cleaning of optical, solar panel, and high emissivity radiator surfaces which have been degraded by contaminants. Future EVA-SCRAM applications are also examined, involving mass production tasks automated with robotics and artificial intelligence, for construction of large truss, aerobrake, and reactor shadow shield structures. Realistically achieving EVA-SCRAM is examined by addressing manual, teleoperated, semi-automated, and fully-automated operation modes. The operational challenges posed by EVA-SCRAM tasks are reviewed with respect to capabilities of existing and upcoming EVA systems, such as the Extravehicular Mobility Unit, the Shuttle Remote Manipulating System, the Dexterous End Effector, and the Servicing Aid Tool

Physical properties of glasses exposed to Earth-facing and trailing-side environments on LDEF

The exposure of 108 glass samples and 12 glass-ceramic samples to Earth-orbit environments permitted measurements which establish the effects of each environment. Examination of five glass types and one glass ceramic located on both the Earth-facing side and the trailing edge revealed no reduction in strength within experimental limits. Strength measurements subjected less than 5 percent of the sample surface area to stresses above 90 percent of the glass's failure strength. Seven micrometeorite or space debris impacts occurred on trailing edge samples. One of those impacts occurred in a location which was subjected to 50 percent of the applied stress at failure. Micrometeorite or space debris impacts were not observed on Earth-facing samples. The physical shape and structure of the impact sites were carefully examined using stereographic scanning electron microscopy. These impacts induce a stress concentration at the damaged region which influences mechanical strength. The flaw size produced by such damage was examined to determine the magnitude of strength degradation in micrometeorite or space-debris impacted glasses. Scanning electron microscopy revealed topographical details of impact sites which included central melt zones and glass fiber production. The overall crater structure is similar to much larger impacts of large meteorite on the Moon in that the melt crater is surrounded by shocked regions of material which fracture zones and spall areas. Residual stresses arising from shock compression and cooling of the fused zone cannot currently be included in fracture mechanics analyses based on simple flaw size examination

Shared morphological consequences of global warming in North American migratory birds

Increasing temperatures associated with climate change are predicted to cause reductions in body size, a key determinant of animal physiology and ecology. Using a four‐decade specimen series of 70 716 individuals of 52 North American migratory bird species, we demonstrate that increasing annual summer temperature over the 40‐year period predicts consistent reductions in body size across these diverse taxa. Concurrently, wing length – an index of body shape that impacts numerous aspects of avian ecology and behaviour – has consistently increased across species. Our findings suggest that warming‐induced body size reduction is a general response to climate change, and reveal a similarly consistent and unexpected shift in body shape. We hypothesise that increasing wing length represents a compensatory adaptation to maintain migration as reductions in body size have increased the metabolic cost of flight. An improved understanding of warming‐induced morphological changes is important for predicting biotic responses to global change.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153188/1/ele13434-sup-0001-Supinfo.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153188/2/ele13434.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153188/3/ele13434_am.pd

The SCRAM tool-kit

This paper proposes a new series of on-orbit capabilities to support the near-term Hubble Space Telescope, Extended Duration Orbiter, Long Duration Orbiter, Space Station Freedom, other orbital platforms, and even the future manned Lunar/Mars missions. These proposed capabilities form a toolkit termed Space Construction, Repair, and Maintenance (SCRAM). SCRAM addresses both intra-Vehicular Activity (IVA) and Extra-Vehicular Activity (EVA) needs. SCRAM provides a variety of tools which enable welding, brazing, cutting, coating, heating, and cleaning, as well as corresponding nondestructive examination. Near-term IVA-SCRAM applications include repair and modification to fluid lines, structure, and laboratory equipment inside a shirt-sleeve environment (i.e. inside Spacelab or Space Station). Near-term EVA-SCRAM applications include construction of fluid lines and structural members, repair of punctures by orbital debris, refurbishment of surfaces eroded by contaminants. The SCRAM tool-kit also promises future EVA applications involving mass production tasks automated by robotics and artificial intelligence, for construction of large truss, aerobrake, and nuclear reactor shadow shields structures. The leading candidate tool processes for SCRAM, currently undergoing research and development, include Electron Beam, Gas Tungsten Arc, Plasma Arc, and Laser Beam. A series of strategic space flight experiments would make SCRAM available to help conquer the space frontier

Irreversible reorganization in a supercooled liquid originates from localised soft modes

The transition of a fluid to a rigid glass upon cooling is a common route of transformation from liquid to solid that embodies the most poorly understood features of both phases1,2,3. From the liquid perspective, the puzzle is to understand stress relaxation in the disordered state. From the perspective of solids, the challenge is to extend our description of structure and its mechanical consequences to materials without long range order. Using computer simulations, we show that the localized low frequency normal modes of a configuration in a supercooled liquid are causally correlated to the irreversible structural reorganization of the particles within that configuration. We also demonstrate that the spatial distribution of these soft local modes can persist in spite of significant particle reorganization. The consequence of these two results is that it is now feasible to construct a theory of relaxation length scales in glass-forming liquids without recourse to dynamics and to explicitly relate molecular properties to their collective relaxation.Comment: Published online: 20 July 2008 | doi:10.1038/nphys1025 Available from http://www.nature.com/nphys/journal/v4/n9/abs/nphys1025.htm

Fluctuations and Intrinsic Pinning in Layered Superconductors

A flux liquid can condense into a smectic crystal in a pure layered superconductors with the magnetic field oriented nearly parallel to the layers. If the smectic order is commensurate with the layering, this crystal is {\sl stable} to point disorder. By tilting and adjusting the magnitude of the applied field, both incommensurate and tilted smectic and crystalline phases are found. We discuss transport near the second order smectic freezing transition, and show that permeation modes lead to a small non--zero resistivity and large but finite tilt modulus in the smectic crystal.Comment: 4 pages + 1 style file + 1 figure (as uufile) appended, REVTEX 3.