Possible evidence for a narrow isovectorB=2 resonance below pion production threshold

Some evidence is presented for a narrow peak at 1969±2 MeV (FWHM=9±2 MeV) in the missing mass spectrum of the³He(p, d) reaction, with 3 standard deviations. The nature of this state, the mass of which is below the NN threshold, is discussed in connection with structures found in other experiments.     

η production in nuclei by protons at Tp≦ 1 GeV

The reactionpA →η X has been measured on⁶Li, C and Cu targets at a proton energy of 0.9 GeV at the SATURNE accelerator. The doubly differential cross sections at T_p=0.9 GeV together with data at T_p=1 GeV, previously presented [1], are analysed in the frame of a recent folding model [3].     

Pion production in 3He-nucleus interactions at 910 MeV

The (³He, π^±X) reaction has been studied at 910 MeV using the ³He⁺⁺ beam of the CERN SC. Complete π^? spectra on CH₂, CD₂, ⁹Be, ¹²C, ²⁷Al, Cd and Pb, and π⁺ spectra on CH₂, CD₂ and ¹²C targets have been measured at 0°, up or close to the kinematic limit x_F = 1. The results are compared to various theoretical calculations.     

Constraints on cosmological parameters from the analysis of the cosmic lens all sky survey radio-selected gravitational lens statistics

We derive constraints on cosmological parameters and the properties of the lensing galaxies from gravitational lens statistics based on the final Cosmic Lens All Sky Survey data. For a flat universe with a classical cosmological constant, we find that the present matter fraction of the critical density is Omega(m)=0.31(+0.27)(-0.14) (68%)+0.12-0.10 (syst). For a flat universe with a constant equation of state for dark energy w=p(x)(pressure)/rho(x)(energy density), we find w<-0.55(+0.18)(-0.11) (68%).     

UTILIZATION OF TOOLS FOR SUCCESSFUL. TROUBLESHOOTING OF STRUCTURAL PROBLEMS

A structural failure problem was solved using an integrated and iterative program of testing and analysis. The steps taken in solving the problem were: analytical calculations; operational testing; qualifications of analytical results; problem identification; design of corrective action; and confirmatory testing.     

Vortex lattice transitions in YNi2B2C

We have performed extensive small-angle neutron scattering (SANS) diffraction studies of the vortex lattice in single crystal YNi₂B₂C for B‖c. High-resolution SANS, combined with a field-oscillation vortex lattice preparation technique, allows us to separate Bragg scattered intensities from two orthogonal domains and accurately determine the unit cell angle, β. The data suggest that upon increasing field there is a finite transition width where both low- and high-field distorted hexagonal vortex lattice phases, mutually rotated by 45°, coexist. The smooth variation of diffracted intensity from each phase through the transition corresponds to a redistribution of populations between the two types of domains.     

The Presence of Hydraulic Barriers in Layered Snowpacks: TOUGH2 Simulations and Estimated Diversion Lengths

The distribution of snow across a landscape is an important component in the hydrologic cycle of many mountainous watersheds. Snow-dominated streams will vary in timing and volume of peak flow depending on when the snow melts and the lag time for the meltwater to reach the stream. As a snowpack accumulates during winter months, variable layers with different hydraulic properties can form hydraulic barriers. Hydraulic barriers were simulated in this study using data from three snow pits located in the Spring Creek Intensive Study Area (part of the NASA CLPX dataset) of Colorado. Data for north, south, and relatively flat aspect slopes were chosen to represent the variable metamorphism that occurs under different conditions. Simulations were conducted at steady-state infiltration rates of 0.1, 1.0, and 5.0 mm/h using the EOS9 module of TOUGH2. Additional diversion length estimates were calculated using existing soil physics approximations for capillary barriers. Results demonstrate that conditions are present within a layered snowpack to produce multiple permeability and capillary barriers, though capillary barriers were only identified in simulations on the north aspect snowpack. Diversion lengths of capillary barriers ranged from 1.0 m to greater than 25 m, and permeability barriers ranged from 2.5 to 9.5 m. Furthermore, a grain size of 0.6 mm or less in the layer above an interface is necessary to produce a capillary barrier. These results suggest that during snowmelt water has high potential to be redistributed downslope prior to infiltrating the ground surface. A better understanding of a snowpack as porous media will improve future hydrologic modeling.     

Flow phenomena in floppy tubes

Collapsible tubes, which occur all over the body, have unique properties from the point of view of both physics and physiology. A brief review is attempted of first the basic observable properties, followed by simple theory to explain the steady-flow aspects and an overview of the somewhat more complex theories for unsteady flow, in particular the flow-induced oscillations. The experimental evidence from laboratory studies is reviewed with particular emphasis on the dynamical system aspects. A final section looks at the current position and prospects.