The microwave transmission system for ERCH on MFTF-B will utilize quasi-optical transmission techniques. The system consists of ten gyrotron oscillators: two gyrotrons at 28 GHz, two at 35 GHz, and six at 56 GHz. The 28 and 35 GHz gyrotrons both heat the electrons in the end plug (potential peak) while the 56 GHz sources heat the minimum-B anchor region (potential minimum). Microwaves are launched into a pair of cylindrical mirrors that form a pseudo-cavity which directs the microwaves through the plasma numerous times before they are lost out of the cavity. The cavity allows the microwave beam to reach the resonance zone over a wide range of plasma densities and temperatures. The fundamental electron cyclotron resonance moves to higher axial positions as a result of beta-depression of the magnetic field, doppler shifting of the resonance, and relativistic mass corrections for the electrons. With this system the microwave beam will reach the resonance surface at the correct angle of incidence for any density or temperature without active aiming of the antennas. The cavity also allows the beam to make multiple passes through the plasma to increase the heating efficiency at low temperatures and densities when the single pass absorption is …

The design of a four-grid, spherically-focused, 10-by-46-cm area accelerator and ion source for the Mirror Fusion Test Facility (MFTF) has been previously described. This source was designed to operate at 80 kV-80 A for 0.5 s, and along with a matching, three-grid 20-kV-100-A-10-ms accelerator, has been built and tested. The 80-kV source has operated beyond design specifications to 90 kV-90 A for 12 ms. Pulse duration was limited by a capacitor bank accelerator power supply. Tests to 0.5 s on the High Voltage Test Stand (HVTS) are in progress. The major change found necessary during testing was the installation of a grounded shield to block neutralizer plasma from flowing into the region between high voltage and ground. The D/sub 1//sup +/:D/sub 2//sup +/:D/sub 3//sup +/ ratio was measured by Doppler shift spectroscopy and momentum analysis to be 0.68:0.20:0.12. Accelerator grids are built to a 7-m-radius spherical surface that aims individual beamlets at the center of curvature.

Chemical and thermal performance of crystalline silicotitanate (CST) and resorcinol-formaldehyde (RF) ion exchange media were predicted for column configurations designed for installation in high level waste tanks and intended for cesium removal from radioactive waste supernates. Modeling predictions for the processing of a known Savannah River Site tank waste composition were generated. In a two column configuration under presumed nominal operating conditions (432 gallon packed bed, 10 gpm liquid flow, 25 C, 45 nCi/g average breakthrough limit) with lead/lag column rotation between processing cycles, approximately two cycles were predicted to treat 1,000,000 gallons of radioactive waste with CST as compared to three cycles predicted for RF. However, this processing mode was shown to be highly unfavorable for RF due to the fact that the lead column is unnecessarily exposed to large radiation doses during movement of the cesium mass transfer zone into the lag column. Thermal modeling calculations indicated that maximum temperatures within stagnant, packed CST and RF columns containing the highest anticipated cesium loading and no active cooling will reach 128 and 78 C, respectively, within 6 days. Active cooling maintains the cesium-saturated CST and RF columns below 88 and 41 C, respectively, under stagnant flow conditions.

Despite some notable successes cancer remains, for the most part, a seemingly intractable problem. There is, however, a growing appreciation that targeting the tumor epithelium in isolation is not sufficient as there is an intricate mutually sustaining synergy between the tumor epithelial cells and their surrounding stroma. As the details of this dialogue emerge, new therapeutic targets have been proposed. The FDA has already approved drugs targeting microenvironmental components such as VEGF and aromatase and many more agents are in the pipeline. In this article, we describe some of the 'druggable' targets and processes within the tumor microenvironment and review the approaches being taken to disrupt these interactions.

The authors present mean reddenings toward 3525 RR0 Lyrae stars from the Galactic bulge fields of the MACHO Survey. These reddenings are determined using the color at minimum V-band light of the RR0 Lyrae stars themselves and are found to be in general agreement with extinction estimates at the same location obtained from other methods. Using 3256 stars located in the Galactic Bulge, they derive the selective extinction coefficient R{sub V,VR} = A{sub V}/E(V-R) = 4.2 {+-} 0.2. this value is what is expected for a standard extinction law with R{sub V,BV} = 3.1 {+-} 0.3

This tutorial gives a brief introduction into passive spectroscopy and describes the working principles of bolometers, a high-resolution grating spectrometer, and a novel X-ray imaging crystal spectrometer, which is of particular interest for profile measurements of the ion temperature and plasma rotation velocity on ITER and future burning plasma experiments.

We carry out a comprehensive theoretical and experimentalstudy of charge injection in poly(3-hexylthiophene) (P3HT) to determinethe most likely scenario for metal-insulator transition in this system.Wecalculate the optical-absorption frequencies corresponding to a polaronand a bipolaron lattice in P3HT. We also analyze the electronicexcitations for three possible scenarios under which a first- or asecond-order metal-insulator transition can occur in doped P3HT. Thesetheoretical scenarios are compared with data from infrared absorptionspectroscopy on P3HT thin-film field-effect transistors (FETs). Ourmeasurements and theoretical predictions suggest that charge-inducedlocalized states in P3HT FETs are bipolarons and that the highest dopinglevel achieved in our experiments approaches that required for afirst-order metal-insulator transition.

Telomeres are maintained by three DNA binding proteins, TRF1, TRF2 and POT1, and several associated factors. One factor, TIN2, binds TRF1 and TRF2 directly and POT1 indirectly. These and two other proteins form a soluble complex that may be the core telomere-maintenance complex. It is not clear whether subcomplexes exist or function in vivo. Here, we provide evidence for two TIN2 subcomplexes with distinct functions in human cells. TIN2 ablation by RNA interference caused telomere uncapping and p53-independent cell death in all cells tested. However, we isolated two TIN2 complexes from cell lysates, each selectively sensitive to a TIN2 mutant (TIN2-13, TIN2-15C). In cells with wild-type p53 function, TIN2-15C was more potent than TIN2-13 in causing telomere uncapping and eventual growth arrest. In cells lacking p53 function, TIN215C more than TIN2-13 caused genomic instability and cell death. Thus, TIN2 subcomplexes likely have distinct functions in telomere maintenance, and may provide selective targets for eliminating cells with mutant p53.

Inertial confinement fusion capsules are critically dependent on the integrity of their hot spots to ignite. At the time of ignition, only a certain fractional perturbation of the nominally spherical hot spot boundary can be tolerated and the capsule still achieve ignition. The degree to which the expected hot spot perturbation in any given capsule design is less than this maximum tolerable perturbation is a measure of the ignition margin or robustness of that design. Moreover, since there will inevitably be uncertainties in the initial character and implosion dynamics of any given capsule, all of which can contribute to the eventual hot spot perturbation, quantifying the robustness of that capsule against a range of parameter variations is an important consideration in the capsule design. Here, the robustness of the 300 eV indirect drive target design for the National Ignition Facility [J. D. Lindl, et al., Phys. Plasmas 11, 339 (2004)] is studied in the parameter space of inner ice roughness, implosion velocity, and capsule scale. A suite of two thousand two-dimensional simulations, run with the radiation hydrodynamics code Lasnex, is used as the data base for the study. For each scale, an ignition region in the two remaining variables is …

The first three-dimensional (3D) simulations of a high power 0.351 {micro}m laser beam propagating through a high temperature hohlraum plasma are reported. We show that 3D linear kinetic modeling of Stimulated Brillouin scattering reproduces quantitatively the experimental measurements, provided it is coupled to detailed hydrodynamics simulation and a realistic description of the laser beam from its millimeter-size envelop down to the micron scale speckles. These simulations accurately predict the strong reduction of SBS measured when polarization smoothing is used.

The influence of the vadose zone, land surface processes, and macrodispersion on scaling behavior of residence time distributions (RTDs) is studied using a fully coupled watershed model in conjunction with a Lagrangian, particle-tracking approach. Numerical experiments are used to simulate groundwater flow paths from recharge locations along the hillslope to the streambed. These experiments are designed to isolate the influences of topography, vadose zone/land surface processes, and macrodispersion on subsurface RTDs of tagged parcels of water. The results of these simulations agree with previous observations that RTDs exhibit fractal behavior, which can be identified from the power spectra. For cases incorporating residence times that are influenced by vadose zone/land surface processes, increasing macrodispersion increases the slope of the power spectra. In general the opposite effect is demonstrated if the vadose zone/land surface processes are neglected. The concept of the spectral slope being a measure of stationarity is raised and discussed.

A complex fracture model for fluid flow and tracer transport was previously developed that incorporates many of the important physical effects of a realistic fracture, including advection through a heterogeneous fracture plane, partitioning of flow into multiple subfractures in the third dimension, and diffusion and sorption into fracture-filling gouge, small altered rock matrix blocks within the fracture zone, and the unaltered semi-infinite rock matrix on both sides of the fracture zone (Tsang and Doughty, 2003). It is common, however, to represent the complex fracture by much simpler models consisting of a single fracture, with a uniform or heterogeneous transmissivity distribution over its plane and bounded on both sides by a homogeneous semi-infinite matrix. Simple-model properties are often inferred from the analysis of short-term (one to a few days) site characterization (SC) tracer-test data. The question addressed in this paper is: How reliable is the temporal upscaling of these simplified models? Are they adequate are for long-term calculations that cover thousands of years? In this study, a particle-tracking approach is used to calculate tracer-test breakthrough curves (BTCs) in a complex fracture model, incorporating all the features described above, for both a short-term SC tracer test and a 10,000-year calculation. The results …

The Kapchinskij-Vladimirskij equations are widely used to study the evolution of the beam envelopes in a periodic system of quadrupole focusing cells. In this paper, we analyze the case of a matched beam. Our model is analogous to that used by Courant and Snyder [E.D. Courant and H.S. Snyder, Ann. Phys. 3, 1 (1958)] in obtaining a first-order approximate solution for a synchrotron. Here, we treat a linear machine and obtain an exact solution. The model uses a full occupancy, piecewise-constant focusing function and neglects space charge. There are solutions in an infinite number of bands as the focus strength is increased. We show that all these bands are stable. Our explicit results for the phase advance {sigma} and the envelope a(z) are exact for all phase advances except multiples of 180{sup o}, where the behavior is singular. We find that the peak envelope size is minimized at {sigma} = 90{sup o}. Actual operation in the higher bands would require very large, very accurate field strengths and would produce significantly larger envelope excursions.

In long adaptive optics corrected exposures, exoplanet detections are currently limited by speckle noise originating from the telescope and instrument optics, and it is expected that such noise will also limit future high-contrast imaging instruments for both ground and space-based telescopes. Previous theoretical analysis have shown that the time intensity variations of a single speckle follows a modified Rician. It is first demonstrated here that for a circular pupil this temporal intensity distribution also represents the speckle spatial intensity distribution at a fix separation from the point spread function center; this fact is demonstrated using numerical simulations for coronagraphic and non-coronagraphic data. The real statistical distribution of the noise needs to be taken into account explicitly when selecting a detection threshold appropriate for some desired confidence level. In this paper, a technique is described to obtain the pixel intensity distribution of an image and its corresponding confidence level as a function of the detection threshold. Using numerical simulations, it is shown that in the presence of speckles noise, a detection threshold up to three times higher is required to obtain a confidence level equivalent to that at 5{sigma} for Gaussian noise. The technique is then tested using TRIDENT CFHT and …

In the protein 4.1R gene, alternative first exons splice differentially to alternative 3' splice sites far downstream in exon 2'/2 (E2'/2). We describe a novel intrasplicing mechanism by which exon 1A (E1A) splices exclusively to the distal E2'/2 acceptor via two nested splicing reactions regulated by novel properties of exon 1B (E1B). E1B behaves as an exon in the first step, using its consensus 5' donor to splice to the proximal E2'/2 acceptor. A long region of downstream intron is excised, juxtaposing E1B with E2'/2 to generate a new composite acceptor containing the E1B branchpoint/pyrimidine tract and E2 distal 3' AG-dinucleotide. Next, the upstream E1A splices over E1B to this distal acceptor, excising the remaining intron plus E1B and E2' to form mature E1A/E2 product. We mapped branch points for both intrasplicing reactions and demonstrated that mutation of the E1B 5' splice site or branchpoint abrogates intrasplicing. In the 4.1R gene, intrasplicing ultimately determines N-terminal protein structure and function. More generally, intrasplicing represents a new mechanism whereby alternative promoters can be coordinated with downstream alternative splicing.

Fluor engineers developed a Gas Tungsten Arc Welding (GTAW) technique and parameters, demonstrated requisite weld quality and successfully closure-welded packaged spent nuclear fuel (SNF) overpacks at the Hanford Site. This paper reviews weld development and qualification activities associated with the overpack closure-welding and provides a summary of the production campaign. The primary requirement of the closure weld is to provide leaktight confinement of the packaged material against release to the environment during interim storage (40-year design term). Required weld quality, in this case, was established through up-front development and qualification, and then verification of parameter compliance during production welding. This approach was implemented to allow for a simpler overpack design and more efficient production operations than possible with approaches using routine post-weld testing and nondestructive examination (NDE). . A series of welding trials were conducted to establish the desired welding technique and parameters. Qualification of the process included statistical evaluation and American Society of Mechanical Engineers (ASME) Section IX testing. In addition, pull testing with a weighted mockup, and thermal calculation/physical testing to identify the maximum temperature the packaged contents would be subject to during welding, was performed. Thirteen overpacks were successfully packaged and placed into interim storage. The closure-welding …

The Thomson Scattering Diagnostic on TMX was built to measure the electron temperature in the plug. The design was based on the 2XII system built by Tom Simonen. Substantial improvements were realized over the original design, these include: (1) improved sensitivity, (2) simultaneous multiple position sampling, (3) multiple pulse capability, (4) achromatic imaging, (5) vacuum alignment capability, (6) high reliability, and (7) built in calibration and performance monitoring.

It is shown that level-density expressions cannot adequately represent or substitute for level structure information when making calculations of the Hauser-Feshbach type for cross sections or isomer-ratios for nuclei in the first few MeV above their ground state. It is stated that such discrete level information should include both experimentally confirmed and theoretically predicted levels. The utility of discrete level information to optimize level density calculations, to compute isomer ratios, in deriving dipole strength functions, and in the analysis of primary gamma ray spectra is emphasized, especially for nuclei far from the line of stability. 29 refs., 12 figs., 6 tabs. (DWL)

This paper describes some of the design features and considerations of the MFTF start-up neutral-beam power supplies. In particular, we emphasize features of the system that will ensure MFTF compatibility and achieve the required reliability/availability for the MFTF to be successful.

A split pair of multifilamentary Nb/sub 3/Sn conductor coils, inside a set of Nb-Ti background coils, is being built at Lawrence Livermore Laboratory (LLL) for use in the High-Field Test Facility (HFTF). The inside diameter of the Nb/sub 3/Sn winding is 40 cm, the peak field is 12 T, and the nominal conductor current is 5 kA. The coils are being built as part of the LLL high-field superconducting development program in which characterization of short samples is followed by demonstration in coils incorporating production lengths of conductor. The HFTF will also be used to study the characteristics of prototype conductors designed to meet the requirements of tokamak toroidal field coils having a maximum field of 12 T. These conductors will be tested one at a time, inserted in the form of small coils in the split between the Nb/sub 3/Sn coils in the HFTF. The paper describes the coil system and gives a summary of the present state of its development and fabrication.

We have calculated the resonant transfer and excitation cross sections in collisions of U{sup q+} (q = 82, 89, 90) ion with H{sub 2}, He and C in impulse approximation using the multi-configuration Dirac-Fock method. The calculations were carried out in intermediate coupling with configuration interaction. The quantum electrodynamic and finite nuclear size corrections were included in the calculations of transition energies. The Auger rates were calculated including the contributions from Coulomb as well as the transverse Breit interactions. For U{sup 89+} and U{sup 90+}, effects of relatively not only shift the peak positions but also change the peak structure. The total dielectronic recombination strength has been found to increase by 50% due to the effects of relativity. The present theoretical RTEX cross sections for U{sup 90+} in hydrogen agree well with experiment. For U{sup 82+}, Breit interaction had been found to have little effect on the RTEX cross sections involving L-shell excitation. However, the spin-orbit interaction can still make significant change in the peak structure. 24 refs., 4 figs.

Using two argon-ion lasers to pump a CW Ti:Sapphire laser we have demonstrated consistent high power (19 watts) operation with a low order spatial mode. Thermal lensing effects were controlled by enclosing the laser in a vacuum and cooling the rod with liquid nitrogen. Using this laser we also demonstrated a CW Ti:Sapphire amplifier with an efficiency of 20%. 5 refs., 5 figs.

Two of the target-physics phenomena which must be understood before a clean experiment can be confidently performed are preheating due to suprathermal electrons and shock decay due to a shock-rarefaction interaction. Simple analytic models are described for these two processes and the predictions of these models are compared with those of the LASNEX fluid physics code. We have approached this work not with the view of surpassing or even approaching the reliability of the code calculations, but rather with the aim of providing simple models which may be used for quick parameter-sensitivity evaluations, while providing physical insight into the problems.

There has been considerable experimental work on same-sign dilepton production in neutrino interactions over the past 10 years. However, the situation is still unclear. Most experiments do have evidence for an excess of candidates but there is a lack of independent statistically significant results. Present experiments at the Tevatron may provide important new information. However the recent revision of older results and the lower rates from recent experiments indicate that real progress will be difficult. Furthermore, the problems encountered with ..pi../K background subtractions argue for a multi-target experiment. Also, given the conflict with present c anti c calculations, a high statistics bubble chamber experiment would be useful to establish the presence/absence of c anti c events at the presently measured production rates. 13 refs., 6 figs., 2 tabs.