High-resolution spectroscopy of hot tokamak plasma seeded with argon ions and interacting with an energetic, short-pulse neutral hydrogen beam was used to obtain the first high-resolution K-shell x-ray spectrum formed solely by charge exchange. The observed K-shell emission of Ar{sup 16+} is dominated by the intercombination and forbidden lines, providing clear signatures of charge exchange. Results from an ab initio atomic cascade model provide excellent agreement, validating a semiclassical approach for calculating charge exchange cross sections.

A new version of the Community Climate System Model (CCSM) has been developed and released to the climate community. CCSM3 is a coupled climate model with components representing the atmosphere, ocean, sea ice, and land surface connected by a flux coupler. CCSM3 is designed to produce realistic simulations over a wide range of spatial resolutions, enabling inexpensive simulations lasting several millennia or detailed studies of continental-scale climate change. This paper will show results from the configuration used for climate-change simulations with a T85 grid for atmosphere and land and a 1-degree grid for ocean and sea-ice. The new system incorporates several significant improvements in the scientific formulation. The enhancements in the model physics are designed to reduce or eliminate several systematic biases in the mean climate produced by previous editions of CCSM. These include new treatments of cloud processes, aerosol radiative forcing, land-atmosphere fluxes, ocean mixed-layer processes, and sea-ice dynamics. There are significant improvements in the sea-ice thickness, polar radiation budgets, equatorial sea-surface temperatures, ocean currents, cloud radiative effects, and ENSO teleconnections. CCSM3 can produce stable climate simulations of millenial duration without ad hoc adjustments to the fluxes exchanged among the component models. Nonetheless, there are still systematic biases in …

The collapse of the Soviet Union sparked fears throughout the world that rogue nations and terrorist organizations would gain access to weapons of mass destruction (WMD). One specific concern has been 'WMD brain drain.' Russians with knowledge about nuclear, chemical, and biological weapons could now depart to any country of their choice, including rogue nations seeking to produce WMD. Meanwhile, Russian science fell into a protracted crisis, with plummeting salaries, little funding for research, and few new recruits to science. These developments increased both the incentives and the opportunities for scientists to sell their knowledge to governments and terrorist organizations with hostile intentions toward the United States. Recognizing the threat of WMD brain drain from Russia, the United States, and other governments implemented a host of programs designed to reduce the risk. Despite, or perhaps partly because of, massive assistance from the West to prevent scientists with WMD knowledge from emigrating, the threat of Russian WMD brain drain has recently faded from view. Yet we have seen no evidence that these programs are effective and little systematic assessment of the current threat of WMD migration. Our data from an unprecedented survey of 602 Russian physicists, biologists, and chemists suggest that …

Although the phylogenetic relationships of many organisms have been convincingly resolved by the comparisons of nucleotide or amino acid sequences, others have remained equivocal despite great effort. Now that large-scale genome sequencing projects are sampling many lineages, it is becoming feasible to compare large data sets of genome-level features and to develop this as a tool for phylogenetic reconstruction that has advantages over conventional sequence comparisons. Although it is unlikely that these will address a large number of evolutionary branch points across the broad tree of life due to the infeasibility of such sampling, they have great potential for convincingly resolving many critical, contested relationships for which no other data seems promising. However, it is important that we recognize potential pitfalls, establish reasonable standards for acceptance, and employ rigorous methodology to guard against a return to earlier days of scenario-driven evolutionary reconstructions.

Supramolecular chemistry represents a way to mimic enzyme reactivity by using specially designed container molecules. We have shown that a chiral self-assembled M{sub 4}L{sub 6} supramolecular tetrahedron can encapsulate a variety of cationic guests, with varying degrees of stereoselectivity. Reactive iridium guests can be encapsulated and the C-H bond activation of aldehydes occurs, with the host cavity controlling the ability of substrates to interact with the metal center based upon size and shape. In addition, the host container can act as a catalyst by itself. By restricting reaction space and preorganizing the substrates into reactive conformations, it accelerates the sigmatropic rearrangement of enammonium cations.

This report addresses the advancement of the ion beam thin film planarization process for the smoothing of substrate particles.

Solid state nuclear magnetic resonance techniques have been used to investigate aging mechanisms in a vinyl chloride:chlorotrifluoroethylene copolymer, FPC-461, due to exposure to {gamma}-radiation. Solid state {sup 1}H MAS NMR spectra revealed structural changes of the polymer upon irradiation under both air and nitrogen atmospheres. Considerable degradation is seen with {sup 1}H NMR in the vinyl chloride region of the polymer, particularly in the samples irradiated in air. {sup 19}F MAS NMR was used to investigate speciation in the chlorotrifluoroethylene blocks, though negligible changes were seen. {sup 1}H and {sup 19}F NMR at elevated temperature revealed increased segmental mobility and decreased structural heterogeneity within the polymer, yielding significant resolution enhancement over room temperature solid state detection. The effects of multi-site exchange are manifest in both the {sup 1}H and {sup 19}F NMR spectra as a line broadening and change in peak position as a function of temperature.

Comparison of mutation spectra at the hypoxanthine-phosphoribosyl transferase (HPRT) gene of peripheral blood T lymphocytes may provide insight into the aetiology of somatic mutation contributing to carcinogenesis and other diseases. To increase knowledge of mutation spectra in healthy people, we have analyzed HPRT mutant T-cells of 50 healthy Russians originally recruited as controls for a study of Chernobyl clean-up workers (Jones et al. Radiation Res. 158, 2002, 424). Reverse transcriptase polymerase chain reactions and DNA sequencing identified 161 independent mutations among 176 thioguanine resistant mutants. Forty (40) mutations affected splicing mechanisms and 27 deletions or insertions of 1 to 60 nucleotides were identified. Ninety four (94) single base substitutions were identified, including 62 different mutations at 55 different nucleotide positions, of which 19 had not previously been reported in human T-cells. Comparison of this base substitution spectrum with mutation spectra in a USA (Burkhart-Schultz et al. Carcinogenesis 17, 1996, 1871) and two Swedish populations (Podlutsky et al, Carcinogenesis 19, 1998, 557, Podlutsky et al. Mutation Res. 431, 1999, 325) revealed similarity in the type, frequency and distribution of mutations in the four spectra, consistent with aetiologies inherent in human metabolism. There were 15-19 identical mutations in the three pair-wise comparisons …

Z-pinch dynamic hohlraum experiments on the Z-Machine at Sandia National Laboratories measured K-shell argon spectra using a focusing spectrometer with spatial resolution. The spectra are modeled using Hullac atomic data input, Cretin nonlocal thermodynamic equilibrium (nlte) atomic kinetics and radiative transfer calculations, and Dakota optimization capabilities. Hullac provides atomic structure and cross section data for Ar XIX, Ar XXVIII (n=1 (illegible) 5), Ar XXVII (n=1 (illegible) 10), and Ar XXVI (n=1 (illegible) 5), where n is the principal quantum number. Cretin calculates the area-integrated spectral intensity escaping an argon doped Dcapsule as a function of electron density, electron temperature, and capsule radius. Dakota optimizes the plasma properties for the best to the measured spectrum by minimizing an objective function comprise of argon spectral line ratios and full-width at half-maximums (fwhms). We highlight the framework of this general spectroscopic capability and discuss the extension to magnetized plasmas using Totalb spectral line shapes.

Tellurium doped AlGaAsSb epitaxial layers were grown lattice-matched on GaSb substrates and lattice-mismatched on semi-insulating GaAs substrates by organometallic vapor phase epitaxy. Secondary ion mass spectroscopy and Hall data showed that the ratio of carrier concentration to Te concentration decreases from 40% to 5% when the Te concentration increases from 4.8 x 10{sup 17} cm{sup -3} to 1.3 x 10{sup 19} cm{sup -3}. Transmission electron microscopy (TEM) showed that the material with heavily doped Te generates a high density (about 10{sup 8} cm{sup 2}) of planar defects. Most of the Te-related defects originate at the GaSb buffer layer/AlGaAsSb epilayer interface. In addition, discrete precipitates were observed in the heavily doped AlGaAsSb layer. TEM imaging revealed amorphous defects (likely residual native oxides) along the GaSb substrate/GaSb buffer interface. High resolution TEM imaging revealed high quality growth beyond the GaSb-buffer/GaSb-substrate interfacial defects. The microstructural impact of GaSb-buffer/GaSb-substrate interface defects on the crystalline quality of AlGaAsSb layers is insignificant.

We present a method for computing a basis of localized orthonormal orbitals (both occupied and virtual), in whose representation the Fock matrix is extremely diagonal-dominant. The existence of these orbitals is shown empirically to be sufficient for achieving highly accurate MP@ energies, calculated according to Kapuy's method. This method (which we abbreviate KMP2), which involves a different partitioning of the n-electron Hamiltonian, scales at most quadratically with potential for linearity in the number of electrons. As such, we believe the KMP2 algorithm presented here could be the basis of a viable approach to local correlation calculations.

First, we review earlier studies reporting possible magnetic characteristics for radiation defects in Pu. We then report, for {alpha}-Pu, two studies of the excess magnetic susceptibility (EMS) due to radiation damage, as a function of time and temperature. We have observed several annealing stages associated with the EMS of the accumulated self-damage and we report that annealing begins at {approx}31K, while below that temperature the displacement damage from self-irradiation of the Pu alpha particle emission and the U recoil are immobile. A detailed investigation was made of this EMS well below the first annealing stage as a function of temperature (2K < T < 15K) and time in a magnetic field of 2T. A linear increase in magnetic susceptibility is seen as a function of time for all isotherms. The excess susceptibility per alpha decay, determined from a linear fit of the slope of the time dependent EMS, is reasonably described with a Curie-Weiss law exhibiting a small negative Weiss temperature. We conclude by describing some future experiments in light of the present results.

The A-01 wetland treatment system (WTS) was designed to remove metals from the effluent at the A-01 NPDES outfall at the Savannah River Site, Aiken, SC. Sequential extraction data was used to evaluate remobilization and retention of Cu, Pb, Zn, Mn, and Fe in the wetland sediment. Remobilization of metals was determined by the Potentially Mobile Fraction (PMF) and metal retention by the Recalcitrant Factor (RF). The PMF, which includes water soluble, exchangeable, and oxides fractions, is the contaminant fraction that has the potential to enter into the mobile aqueous phase under changeable environmental conditions. PMF values were low for Cu, Zn and Pb (about 20 percent) and high for Fe and Mn (about 60 to 70 percent). The RF, which includes crystalline oxides, sulfides or silicates and aluminosilicates, is the ratio of strongly bound fractions to the total concentration of elements in sediment. RF values were about 80 percent for Cu, Zn and Pb, indicating high retention in the sediment and 30 percent to above 40 percent for Fe and Mn indication low retention.

We present now a possible way to carry out soft-x-rayfluorescence spectroscopy of liquids. The liquid cell has a window toattain compatibility with UHV conditions of the spectrometer andbeamline, The synchrotron radiation enters the liquid cell through a 100nm-thick silicon nitride window and the emitted xrays exit through thesame window. This allows in particular liquid solid interfaces to bestudied. Such a liquid cell has been used to study the electronicstructure of a variety of systems ranging from water solutions ofinorganic salts and inertial drugs to nano materials and actinidecompounds in their wet conditions.

We have recently completed a large-area, coded-aperture, gamma-ray imager for use in searching for radiation sources. The instrument was constructed to verify that weak point sources can be detected at considerable distances if one uses imaging to overcome fluctuations in the natural background. The instrument uses a rank-19, one-dimensional coded aperture to cast shadow patterns onto a 0.57 m{sup 2} NaI(Tl) detector composed of 57 individual cubes each 10 cm on a side. These are arranged in a 19 x 3 array. The mask is composed of four-centimeter thick, one-meter high, 10-cm wide lead blocks. The instrument is mounted in the back of a small truck from which images are obtained as one drives through a region. Results of first measurements obtained with the system are presented.

Supersymmetric models have traditionally been assumed to be perturbative up to high scales due to the requirement of calculable unification. In this note I review the recently proposed `Fat Higgs' model which relaxes the requirement of perturbativity. In this framework, an NMSSM-like trilinear coupling becomes strong at some intermediate scale. The NMSSM Higgses are meson composites of an asymptotically-free gauge theory. This allows us to raise the mass of the Higgs, thus alleviating the MSSM of its fine tuning problem. Despite the strong coupling at an intermediate scale, the UV completion allows us to maintain gauge coupling unification.

Lawrence Livermore National Laboratory is in the process of developing a new Monte Carlo Particle Transport code named MERCURY. This new code features a 3-D Combinatorial Geometry tracking algorithm. This paper details some of the characteristics of this Monte Carlo tracker

The change in the electronic structure of germanium nanocrystals is investigated as their concentration is increased from non-interacting, individual particles to assembled arrays of particles. The electronic structure of the individual nanoclusters shows clear effects due to quantum confinement which are lost in the concentrated assemblies of bare particles. When the surface of the individual particles is passivated, they retain their quantum confinement properties also upon assembly. These effects are interpreted in terms of a particle - particle interaction model.

The coupling of statistical cloud schemes with mass-flux convection schemes is addressed. Source terms representing the impact of convection are derived within the framework of prognostic equations for the width and asymmetry of the probability distribution function of total water mixing ratio. The accuracy of these source terms is quantified by examining output from a cloud resolving model simulation of deep convection. Practical suggestions for inclusion of these source terms in large-scale models are offered.

The controlled integration of organic and inorganic components confers natural bone with superior mechanical properties. Bone biogenesis is thought to occur by templated mineralization of hard apatite crystals by an elastic protein scaffold, a process we sought to emulate with synthetic biomimetic hydrogel polymers. Crosslinked polymethacrylamide and polymethacrylate hydrogels were functionalized with mineral-binding ligands and used to template the formation of hydroxyapatite. Strong adhesion between the organic and inorganic materials was achieved for hydrogels functionalized with either carboxylate or hydroxy ligands. The mineral-nucleating potential of hydroxyl groups identified here broadens the design parameters for synthetic bone-like composites and suggests a potential role for hydroxylated collagen proteins in bone mineralization.

We have searched for neutrons from the 3-body photon-induced reaction {sup 9}Be + {gamma} {yields} {alpha} + {alpha} + n using bremsstrahlung produced by electrons from a 2-MV Van de Graaff. The target was located within a block of beryllium surrounded by an array of {sup 3}He proportional counters embedded in paraffin. Based on energy and intensity calibrations of the accelerator and detector using the {sup 9}Be + {gamma} {yields} {sup 8}Be + n reaction, an upper limit of 93 nb (4{sigma}) was placed on the cross section for neutron production between the 3-body and 2-body thresholds. This value is substantially below a previously experimental result using photoexcitation by a {sup 142}Pr gamma source and also below an earlier theoretical estimate. We suggest that bremsstrahlung due to beta rays between 1665 keV and the 2160-keV end-point of the {sup 142}Pr beta-ray spectrum could account for the photoneutron yield in the 3-body region that had previously been attributed to {sup 142}Pr gamma rays.

Synchrotron radiation from the Advanced Light Source has been used to investigate the electronic structure of {alpha}-Pu and {delta}-Pu. Measurements include core level and valence band photoelectron spectroscopy, Resonant Photoelectron Spectroscopy (REPES), and X-ray Absorption Spectroscopy (XAS).

Multidimensional hydrodynamic properties of high-adiabat direct-drive plastic-shell implosions on the OMEGA laser system [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] are investigated using the multidimensional hydrodynamic code, DRACO. Multimode simulations including the effects of nonuniform illumination and target roughness indicate that shell stability during the acceleration phase plays a critical role in determining target performance. For thick shells that remain integral during the acceleration phase, target yields are significantly reduced by the combination of the long-wavelength ({ell} < 10) modes due to surface roughness and beam imbalance and the intermediate modes (20 {le} {ell} {le} 50) due to single-beam nonuniformities. The neutron-production rate for these thick shells truncates relative to one-dimensional (1-D) predictions. The yield degradation in the thin shells is mainly due to shell breakup at short wavelengths ({lambda} {approx} {Delta}, where {Delta} is the in-flight shell thickness). The neutron-rate curves for the thinner shells have significantly lower amplitudes and a fall-off that is less steep than 1-D rates. DRACO simulation results are consistent with experimental observations.

Atomic structure codes have a difficult time accurately calculating the wavelengths of many-electron ions without the benefit of laboratory measurements. This is especially true for wavelengths of lines in the extreme ultraviolet and soft x-ray regions. We are using the low-energy capability of the Livermore electron beam ion traps to compile a comprehensive catalog of astrophysically relevant emission lines in support of satellite x-ray observations. Our database includes wavelength measurements, relative intensities, and line assignments, and is compared to a full set of calculations using the Hebrew University - Lawrence Livermore Atomic Code (HULLAC). Mean deviation of HULLAC calculations from our measured wavelength values is highest for L-shell transitions of neon-like ions and lowest for lithium-like ions, ranging from a mean deviation of over 0.5 {angstrom} for Si V to 12 m{angstrom} in Ar XVI.