5,294 research outputs found
Accelerometers can measure total and activity-specific energy expenditures in free-ranging marine mammals only if linked to time-activity budgets
Peer reviewedPostprin
Multi-use lunar telescopes
The objective of multi-use telescopes is to reduce the initial and operational costs of space telescopes to the point where a fair number of telescopes, a dozen or so, would be affordable. The basic approach is to develop a common telescope, control system, and power and communications subsystem that can be used with a wide variety of instrument payloads, i.e., imaging CCD cameras, photometers, spectrographs, etc. By having such a multi-use and multi-user telescope, a common practice for earth-based telescopes, development cost can be shared across many telescopes, and the telescopes can be produced in economical batches
CP-PACS Result for the Quenched Light Hadron Spectrum
The quenched hadron spectrum in the continuum obtained with the Wilson quark
action in recent simulations on the CP-PACS is presented. Results for the light
quark masses and the QCD scale parameter are reported.Comment: Talk presented by K. Kanaya at Lattice97, Edinburg
CP-PACS results for quenched QCD spectrum with the Wilson action
We present progress report of a CP-PACS calculation of quenched QCD spectrum
with the Wilson quark action. Light hadron masses and meson decay constants are
obtained at 5.9, 6.1, and 6.25 on lattices with a physical extent of 3
fm, and for the range of quark mass corresponding to 0.4. Nucleon mass at each appears to be a convex function of
quark mass, and consequently the value at the physical quark mass is much
smaller than previously thought. Hadron masses extrapolated to the continuum
limit exhibits a significant deviation from experimental values: with meson
mass to fix strange quark mass, strange meson and baryon masses are
systematically lower. Light quark masses determined from the axial Ward
identity are shown to agree with those from perturbation theory in the
continuum limit. Decay constants of mesons are also discussed.Comment: 12 pages, Latex(espcrc2,epsf), 17 ps figures. Talk presented by
T.Yoshi\'e at the International Workshop on ``LATTICE QCD ON PARALLEL
COMPUTERS'', 10-15 March 1997, Center for Computational Physics, University
of Tsukub
Radiative Decay Using Heavy Quark and Chiral Symmetry
The implications of chiral symmetry and heavy quark
symmetry for the radiative decays , ,
and are discussed. Particular attention is paid to
violating contributions of order . Experimental data on these
radiative decays provide constraints on the coupling.Comment: 9 pages plus 3 pages of figures in POSTSCRIPT file appended to TeX
file (uses harvmac.tex and tables.tex), UCSD/PTH 92-31, CALT-68-1816,
EFI-92-45, CERN-TH.6650/9
Quenched Light Hadron Spectrum with the Wilson Quark Action: Final Results from CP-PACS
We report the final results of the CP-PACS calculation for the quenched light
hadron spectrum with the Wilson quark action. Our data support the presence of
quenched chiral singularities, and this motivates us to use mass formulae based
on quenched chiral perturbation theory in order to extrapolate hadron masses to
the physical point. Hadron masses and decay constants in the continuum limit
show unambiguous systematic deviations from experiment. We also report the
results for light quark masses.Comment: LATTICE98(spectrum). The poster at Lattice98 can be obtained from
http://www.rccp.tsukuba.ac.jp/people/yoshie/Lat98.Poster
Surface ocean-lower atmosphere study: Scientific synthesis and contribution to Earth system science
The domain of the surface ocean and lower atmosphere is a complex, highly dynamic component of the Earth system. Better understanding of the physics and biogeochemistry of the air-sea interface and the processes that control the exchange of mass and energy across that boundary define the scope of the Surface Ocean-Lower Atmosphere Study (SOLAS) project. The scientific questions driving SOLAS research, as laid out in the SOLAS Science Plan and Implementation Strategy for the period 2004-2014, are highly challenging, inherently multidisciplinary and broad. During that decade, SOLAS has significantly advanced our knowledge. Discoveries related to the physics of exchange, global trace gas budgets and atmospheric chemistry, the CLAW hypothesis (named after its authors, Charlson, Lovelock, Andreae and Warren), and the influence of nutrients and ocean productivity on important biogeochemical cycles, have substantially changed our views of how the Earth system works and revealed knowledge gaps in our understanding. As such SOLAS has been instrumental in contributing to the International Geosphere Biosphere Programme (IGBP) mission of identification and assessment of risks posed to society and ecosystems by major changes in the EarthÌs biological, chemical and physical cycles and processes during the Anthropocene epoch. SOLAS is a bottom-up organization, whose scientific priorities evolve in response to scientific developments and community needs, which has led to the launch of a new 10-year phase. SOLAS (2015â2025) will focus on five core science themes that will provide a scientific basis for understanding and projecting future environmental change and for developing tools to inform societal decision-making
CD2AP links cortactin and capping protein at the cell periphery to facilitate formation of lamellipodia
Understanding the physiology of complex relationships between components of signaling pathways and the actin cytoskeleton is an important challenge. CD2AP is a membrane scaffold protein implicated in a variety of physiological and disease processes. The physiological function of CD2AP is unclear, but its biochemical interactions suggest that it has a role in dynamic actin assembly. Here, we report that CD2AP functions to facilitate the recruitment of actin capping protein (CP) to the Src kinase substrate, cortactin, at the cell periphery, and that this is necessary for formation of the short branched filaments that characterize lamellipodium formation and are required for cell migration. Superresolution fluorescence microscopy demonstrated that the efficient colocalization of CP and cortactin at the cell periphery required CD2AP. As both cortactin and CP function to enhance branched actin filament formation, CD2AP functions synergistically to enhance the function of both proteins. Our data demonstrate how the interplay between specialized actin regulatory molecules shapes the actin cytoskeleton
From Notes to Chords in QCD
After a very brief overview recollecting the `classic' parts of QCD, that is
its application to describe hard processes and static properties of hadrons, I
survey recent work -- some very recent -- on QCD at non-zero temperature and
density. At finite temperature and zero density there is a compelling
theoretical framework allowing us to predict highly specific, non-trivial
dependence of the phase structure on the number of flavors and colors. Several
aspects have been rigorously, and successfully, tested against massive
numerical realizations of the microscopic theory. The theoretical description
of high density is nowhere near as mature, but some intriguing possibilities
have been put forward. The color/flavor locked state recently proposed for
three flavors has many remarkable features connected to its basic symmetry
structure, notably including chiral symmetry re-breaking and the existence
(unlike for two flavors) of a gauge invariant order parameter. I survey
potential applications to heavy ion collisions, astrophysics, and cosmology. A
noteworthy possibility is that stellar explosions are powered by release of QCD
latent heat.Comment: LaTeX, 13 pages, 1 figure. Reference added. Will appear in
Proceedings of QCD at Finite Baryon Density Conference, April 1998,
Universitaet Bielefeld, German
Full QCD simulation on CP-PACS
A status report is made of an on-going full QCD study on the CP-PACS aiming
at a comparative analysis of the effects of improving gauge and quark actions
on hadronic quantities and static quark potential. Simulations are made for
four action combinations, the plaquette or an RG-improved action for gluons and
the Wilson or SW-clover action for quarks, at -1.3GeV and
-0.9. Results demonstrate clearly that the clover
term markedly reduces discretization errors for hadron spectrum, while adding
six-link terms to the plaquette action leads to much better rotational symmetry
in the potential. These results extend experience with quenched simulations to
full QCD.Comment: Talk presented by K. Kanaya at the International Workshop on
``LATTICE QCD ON PARALLEL COMPUTERS'', 10-15 March 1997, Center for
Computational Physics, University of Tsukub
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