2,275 research outputs found
Review of Eustochus, a rarely collected genus of Mymaridae (Hymenoptera)
The four nominal species of Eustochus are reviewed. Four new species, E. confusus from Spain, E. pengellyi and E. yoshimotoi from North America, and E. nipponicus from Japan are described and a key to the eight species is given
Possible Explanations for the NuTeV Weinberg Angle Measurement
The NuTeV collaboration has made an independent determination of the Weinberg
angle by measuring charged and neutral-current cross sections from neutrino and
antineutrino DIS on iron. Their value differs by 3 standard deviations from
that obtained from measurements at the Z pole. We review this experiment and
assess various possible explanations for this result, both within the Standard
Model ("old physics") and outside the Standard Model ("new physics").Comment: QCD Down Under Workshop, CSSM, Adelaide, Australia, Mar 10-19, 2004;
6 pages, 3 figs; updated references on QCD effect
Saltmarsh resilience to periodic shifts in tidal channels
Resilience of coastal ecosystems to climate change is largely determined by the interaction between plants and the surrounding tidal environment. Research has tended to focus on processes operating at the local scale to explain resilience mechanisms, overlooking potentially important landscape-scale processes and patterns. We show from aerial images spanning 67 years across 3 estuaries that saltmarsh loss was compensated by expansion elsewhere in the estuary when tidal channels shifted position. Compensatory expansion rates were as high as 6 m/yr. This phenomenon of “geomorphic compensation” represents a hitherto overlooked large-scale self-organizing pattern that facilitates the long-term persistence of marshes in estuaries. The geomorphic compensation pattern likely also occurs in other hydrological systems including mangrove forests, and seagrass meadows, and river islands. Compensatory erosion-expansion patterns occurred at the same time as net marsh extent increased by between 120 and 235% across all three estuaries. Marsh expansion mostly occurred in the lower parts of each estuary, where channel migration and compensatory expansion was less evident. Patterns of geomorphic compensation therefore appear to operate at discrete spatio-temporal scales, nested within a hierarchy of coastal morphodynamic processes that govern longer-term patterns of either net marsh gain or loss. Coastal ecosystem resilience can therefore only be fully appreciated when examining erosion and expansion patterns at both local and landscape scales. The intrinsic dynamics of marshes described here have important implications for the long-term delivery of ecosystem services
Electrostatic theory for imaging experiments on local charges in quantum Hall systems
We use a simple electrostatic treatment to model recent experiments on
quantum Hall systems, in which charging of localised states by addition of
integer or fractionally-charged quasiparticles is observed. Treating the
localised state as a compressible quantum dot or antidot embedded in an
incompressible background, we calculate the electrostatic potential in its
vicinity as a function of its charge, and the chemical potential values at
which its charge changes. The results offer a quantitative framework for
analysis of the observations.Comment: 4 pages, 3 figure
On Bogovski\u{\i} and regularized Poincar\'e integral operators for de Rham complexes on Lipschitz domains
We study integral operators related to a regularized version of the classical
Poincar\'e path integral and the adjoint class generalizing Bogovski\u{\i}'s
integral operator, acting on differential forms in . We prove that these
operators are pseudodifferential operators of order -1. The Poincar\'e-type
operators map polynomials to polynomials and can have applications in finite
element analysis. For a domain starlike with respect to a ball, the special
support properties of the operators imply regularity for the de Rham complex
without boundary conditions (using Poincar\'e-type operators) and with full
Dirichlet boundary conditions (using Bogovski\u{\i}-type operators). For
bounded Lipschitz domains, the same regularity results hold, and in addition we
show that the cohomology spaces can always be represented by
functions.Comment: 23 page
Turbulent superfluid profiles in a counterflow channel
We have developed a two-dimensional model of quantised vortices in helium II
moving under the influence of applied normal fluid and superfluid in a
counterflow channel. We predict superfluid and vortex-line density profiles
which could be experimentally tested using recently developed visualization
techniques.Comment: 3 double figures, 9 page
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Use of chlorine-36 and other geochemical data to test a groundwater flow model for Yucca Mountain, Nevada
Defining the spatial distribution and timing of subsurface fluid percolation is one of the most important factors determining long term performance of the potential high-level radioactive waste repository at Yucca Mountain, Nevada. The nonwelded interval of the Paintbrush Group (PTn), which overlies most of the potential repository, has high matrix porosities and permeabilities and is mostly unfractured. The Exploratory Studies Facility (ESF) is a 8-km long, 7.6-m diameter, tunnel excavated beneath Yucca Mountain to the level of the potential repository horizon in order to provide access for characterization of these rocks. Several samples collected within the ESF have measured {sup 36}Cl/Cl ratios that record anthropogenic {sup 36}Cl (bomb-pulse {sup 36}Cl), indicating that at least some fraction of the water has traversed the overlying PTn in 40 years or less and that flow is not confined to the matrix of that unit. The presence of a fast path transmitting bomb-pulse {sup 36}Cl to depth appears to require the simultaneous presence of a structure (such as a fault) cutting the PTn and sufficiently high magnitude to surface infiltration to initiate and sustain at least a small component of fracture flow along the connected fracture path associated with the structure. The {sup 36}Cl data have been simulated using the flow and transport model FEHM in order to establish bounds on infiltration rates at the site and to provide greater confidence in the understanding of unsaturated flow processes at the site by showing consistency between the observed and simulated data sets. An analogous effort simulating the distribution of porewater chloride concentrations is providing an independent means for confirming the conceptual model
Does experience influence the forces exerted on maxillary incisors during laryngoscopy? A manikin study using the Macintosh laryngoscope
The influence of the level of experience of the laryngoscopist on the duration of laryngoscopy, the forces exerted on the tongue and on the maxillary incisors during laryngoscopy, were investigated. Five groups (anaesthetists, residents in anaesthesia, nurse anaesthetists, surgeons and medical students), each consisting of 15 individuals, participated in the study. An intubation manikin was used with a laryngoscope modified so that the forces applied during laryngoscopy could be measured. The mean duration of laryngoscopy in these groups was 23.4 sec, 17.6 sec, 27.1 sec, 26.8 sec and 42.7 sec, respectively. The maximally applied forces on the tongue were 71.7 N, 60.5 N, 65.9 N, 74.2 N and 69.7 N, respectively. The maximally applied forces on the maxillary incisors were 49.9 N, 36.3 N, 41.1 N, 58.3 N and 53.9 N, respectively. These results indicate the level of experience has a significant influence on the duration of laryngoscopy but seems to have little influence on the forces applied to the tongue and the maxillary incisors
Charge Symmetry Violating Contributions to Neutrino Reactions
The NuTeV group has measured charged and neutral current reactions for
neutrinos on iron targets. Ratios of these cross sections provide an
independent measurement of the Weinberg angle. The NuTeV value for sin^2
theta_W is three standard deviations larger than the value measured in other
electroweak processes. By reviewing theoretical estimates of parton charge
symmetry violation (CSV), we study CSV contributions to the NuTeV measurement.
We conclude that charge symmetry violating effects should remove roughly 30% of
the discrepancy between the NuTeV result and other determinations of sin^2
theta_W.Comment: 15 pages, 2 figures; Fig 2 replaced [CSV distribution calculated at
low Q^2, evolved to 20 GeV^2]; table II change
Effectiveness of social management training on executive functions in males with Klinefelter syndrome (47, XXY)
Education and Child Studie
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