Migration of pre-characterized carbon dust in a tokamak environment was studied by introducing about 30 milligrams of dust flakes 5-10 {micro}m in diameter in the lower divertor of DIII-D using the DiMES sample holder. The dust was exposed to high power ELMing Hmode discharges in lower-single-null magnetic configuration with the strike points swept across the divertor floor. When the outer strike point (OSP) passed over the dust holder exposing it to high particle and heat fluxes, part of the dust was injected into the plasma. In about 0.1 sec following the OSP pass over the dust, 1-2% of the total dust carbon content (2-4 x 10{sup 19} carbon atoms, equivalent to a few million dust particles) penetrated the core plasma, raising the core carbon density by a factor of 2-3. When the OSP was inboard of the dust holder, the dust injection continued at a lower rate. Individual dust particles were observed moving at velocities of 10-100 m/s, predominantly in the toroidal direction for deuteron flow to the outer divertor target, consistent with the ion drag force. The observed behavior of the dust is in qualitative agreement with modeling by the 3D DustT code.

A tensonometer for stretching metal foils has beenconstructed for the study of strain broadening in x-ray diffraction lineprofiles. This device, which is designed for use on the powderdiffractometer in Station 2.3 at Daresbury Laboratory, allows in-situmeasurements to be performed on samples under stress. It can be used fordata collection in either transmission or reflection modes using eithersymmetric or asymmetric diffraction geometries. As a test case,measurements were carried out on a 18mum thick copper foil experiencingstrain levels of up to 5 percent using both symmetric reflection andsymmetric transmission diffraction. All the diffraction profilesdisplayed peak broadening and asymmetry which increased with strain. Themeasured profiles were analysed by the fundamental parameters approachusing the TOPAS peak fitting software. All the observed broadenedprofiles were modelled by convoluting a refineable diffraction profile,representing the dislocation and crystallite size broadening, with afixed instrumental profile pre-determined usinghigh quality LaB6reference powder. The de-convolution process yielded "pure" sampleintegral breadths and asymmetry results which displayed a strongdependence on applied strain and increased almost linearly with appliedstrain. Assuming crystallite size broadening in combination withdislocation broadening arising from fcc a/2<110>111 dislocations,we have extracted the variation of mechanic al property with strain. Theobservation of both peak asymmetry and broadening has been interpreted asa manifestation of …

Advanced neutron interrogation systems for the screening ofsea-land cargo containers for shielded special nuclear materials (SNM)require a high-yield neutron source to achieve the desired detectionprobability, false alarm rate, and throughput. An accelerator-drivenneutron source is described that produces a forward directed beam ofhigh-energy (up to 8.5 MeV) neutrons utilizing the D(d,n)3He reaction atdeuteron beam energies of up to 6 MeV. The key components of the neutronsource are a high-current RFQ accelerator and an innovative neutronproduction target. A microwave-driven deuteron source is coupled to anelectrostatic LEBT that injects a 40 mA D+-beam into a 6 MeV, 5.1meter-long, 200 MHz RFQ. The RFQ is based on an unusual beam dynamicsdesign and is capable of operating at a duty factor that produces morethan 1.2 mA timeaverage beam current. The beam is transported to a2-atmosphere deuterium gas target with a specially-designed, thinentrance window. A high-frequency dipole magnet is used to spread thebeam over the long dimension of the 4 by 35 cm target window. The sourcewill be capable of delivering a neutron flux of ~;2 x 107 n/(cm2 x s) tothe center of a sea-land cargo container and is expected t o satisfy therequirements for full testing and demonstration of advanced neutroninterrogation techniques based on …

The electrostatic particle-in-cell codeWARP is currently being expanded in order to study electron cloud effects on the dynamics of the beam in storage rings. Results for the Fermilab main injector (MI) show the existence of a threshold in the electron density beyond which there is rapid emittance growth. The Fermilab MI is being considered for an upgrade as part of the high intensity neutrino source (HINS) effort, which will result in a significant increasing of the bunch intensity relative to its present value, placing it in a regime where electron-cloud effects are expected to become important. Various results from the simulations using WARP are discussed here.

A novel exon microarray format that probes gene expression with single exon resolution was employed to elucidate critical features of a vertebrate muscle alternative splicing program. A dataset of 56 microarray-defined, muscle-enriched exons and their flanking introns were examined computationally in order to investigate coordination of the muscle splicing program. Candidate intron regulatory motifs were required to meet several stringent criteria: significant over-representation near muscle-enriched exons, correlation with muscle expression, and phylogenetic conservation among genomes of several vertebrate orders. Three classes of regulatory motifs were identified in the proximal downstream intron, within 200nt of the target exons: UGCAUG, a specific binding site for Fox-1 related splicing factors; ACUAAC, a novel branchpoint-like element; and UG-/UGC-rich elements characteristic of binding sites for CELF splicing factors. UGCAUG was remarkably enriched, being present in nearly one-half of all cases. These studies suggest that Fox and CELF splicing factors play a major role in enforcing the muscle-specific alternative splicing program, facilitating expression of a set of unique isoforms of cytoskeletal proteins that are critical to muscle cell differentiation. Supplementary materials: There are four supplementary tables and one supplementary figure. The tables provide additional detailed information concerning the muscle-enriched datasets, and about over-represented oligonucleotide sequences in …

A high-yield D-T neutron generator has been developed for neutron interrogation in homeland security applications such as cargo screening. The generator has been designed as a sealed tube with a performance goal of producing 5 {center_dot} 10{sup 11} n/s over a long lifetime. The key generator components developed are a radio-frequency (RF) driven ion source and a beam-loaded neutron production target that can handle a beam power of 10 kW. The ion source can provide a 100 mA D{sup +}/T{sup +} beam current with a high fraction of atomic species and can be pulsed up to frequencies of several kHz for pulsed neutron generator operation. Testing in D-D operation has been started.

This paper provides a comparative discussion of coupledhydromechanical processes in three different geological formations:crystalline rock, plastic clay, and indurated clay. First, the importantprocesses and associated property characteristics in the three rock typesare discussed. Then, one particular hydromechanical coupling is broughtup for detailed consideration, that of pore pressure changes in nearbyrock during tunnel excavation. Three field experiments in the three rocktypes are presented and their results are discussed. It is shown that themain physical processes are common to all three rock types, but with verydifferent time constants. The different issues raised by these cases arepointed out, and the transferable lessons learned are identified. Suchcross fertilization and simultaneous understanding of coupled processesin three very different rock types help to greatly enhance confidence inthe state of science in this field.

The Fermilab main injector (MI) is being considered for an upgrade as part of the high intensity neutrino source (HINS) effort. This upgrade will involve a significant increasing of the bunch intensity relative to its present value. Such an increase will place the MI in a regime in which electron-cloud effects are expected to become important. We have used the electrostatic particle-in-cell code WARP, recently augmented with new modeling capabilities and simulation techniques, to study the dynamics of beam-electron cloud interaction. This work in progress involves a systematic assessment of beam instabilities due to the presence of electron clouds.

Anomalous first-wall heating has been observed far from the divertor strike point during QH-mode in DIII-D, with measured heat flux comparable to that at the outer strike point. The data are consistent with deuterium ions of approximately the pedestal energy carrying the anomalous heat flux. Although an instability has not been identified that is correlated with the anomalous heat flux, two classes of behavior have been observed: one in which the anomalous heat flux depends linearly on core {beta}, and another class with no {beta}-dependence. The anomalous heat flux depends strongly on the injected beam energy of the non-tangentially-injected neutral beams but not that of the tangential beams.

A wide variety of vacua, and their cosmological realization, may provide an explanation for the apparently anthropic choices of some parameters of particle physics and cosmology. If the probability on various parameters is weighted by volume, a flat potential for slow-roll inflation is also naturally understood, since the flatter the potential the larger the volume of the sub-universe. However, such inflationary landscapes have a serious problem, predicting an environment that makes it exponentially hard for observers to exist and giving an exponentially small probability for a moderate universe like ours. A general solution to this problem is proposed, and is illustrated in the context of inflaton decay and leptogenesis, leading to an upper bound on the reheating temperature in our sub-universe. In a particular scenario of chaotic inflation and non-thermal leptogenesis, predictions can be made for the size of CP violating phases, the rate of neutrinoless double beta decay and, in the case of theories with gauge-mediated weak scale supersymmetry, for the fundamental scale of supersymmetry breaking.

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There are several indications that an opaque partonic medium is created in energetic Au+Au collisions ({radical}s{sub NN} {approx} GeV/nucleon) at the Relativistic Heavy Ion Collider (RHIC). At the extreme densities of {approx} 10-100 times normal nuclear density reached even heavy-flavor hadrons are affected significantly. Heavy-quark observables are presented from the parton transport model MPC, focusing on the nuclear suppression pattern, azimuthal anisotropy (''elliptic flow''), and azimuthal correlations. Comparison with Au + Au data at top RHIC energy {radical}s{sub NN} = 200 GeV indicates significant heavy quark rescattering, corresponding roughly five times higher opacities than estimates based on leading-order perturbative QCD. We propose measurements of charm-anticharm, e.g., D-meson azimuthal correlations as a sensitive, independent probe to corroborate these findings.

The design of future spacecraft such as the Crew ExplorationVehicle must take into account the radiation shielding properties of boththe structural components as well as dedicated shielding materials. Sincemodest depths of shielding stop the vast majority of Solar EnergeticParticles (SEP), the greater challenge is posed by the need to shieldcrew from the Galactic Cosmic Rays (GCR), which include highly-chargedand highly-energetic particles. Here, we report on results from testsperformed with beams of 1 GeV/nuc 56Fe at the Brookhaven NationalLaboratory. A wide variety of targets, both elemental and composite, wereplaced in the particle beams, and the spectra of particles emerging fromthe targets were measured using a stack of silicon detectors. Results arepresented primarily in terms of dose reduction per g cm-2 of targetmaterial, and support the conclusions of an earlier calculation by Wilsonet al. showing that performance improves as the shield's mass numberdecreases, with hydrogen being by far the most effective. The data alsoshow that, as depth increases, the incremental benefit of addingshielding decreases, particularlyfor aluminum and other elements withhigher atomic mass numbers.

The authors report the first observation of an excited singly-charmed baryon {Omega}*{sub c} (css) in the radiative decay {Omega}{sub c}{sup 0}{gamma}, where the {Omega}{sub c}{sup 0} baryon is reconstructed in the decays to the final states {Omega}{sup -}{pi}{sup +}, {Omega}{sup -} {pi}{sup +}{pi}{sup 0}, {Omega}{sup -}{pi}{sup +}{pi}{sup -}{pi}{sup +}, and {Xi}{sup -} K{sup -} {pi}{sup +}{pi}{sup +}. This analysis is performed using a dataset of 230.7 fb{sup -1} collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at the Stanford Linear Accelerator Center. The mass difference between the {Omega}*{sub c} and the {Omega}{sub c}{sup 0} baryons is measured to be 70.8 {+-} 1.0(stat) {+-} 1.1(syst) MeV/c{sup 2}. They also measure the ratio of inclusive production cross sections of {Omega}*{sub c} and {Omega}{sub c}{sup 0} in e{sup +}e{sup -} annihilation.

Erythroid progenitors differentiate in erythroblastic islands, bone marrow niches composed of erythroblasts surrounding a central macrophage. Evidence suggests that within islands adhesive interactions regulate erythropoiesis and apoptosis. We are exploring whether erythroid intercellular adhesion molecule-4 (ICAM-4), animmunoglobulin superfamily member, participates in island formation. Earlier, we identified alpha V integrins as ICAM-4 counter receptors. Since macrophages express alpha V, ICAM-4 potentially mediates island attachments. To test this, we generated ICAM-4 knockout mice and developed quantitative, live cell techniques for harvesting intact islands and for reforming islands in vitro. We observed a 47 percent decrease in islands reconstituted from ICAM-4 null marrow compared to wild type. We also found a striking decrease in islands formed in vivo in knockout mice. Further, peptides that block ICAM-4 alpha V adhesion produced a 53-57 percent decrease in reconstituted islands, strongly suggesting that ICAM-4 binding to macrophage alpha V functions in island integrity. Importantly, we documented that alpha V integrin is expressed in macrophages isolated from erythro blastic islands. Collectively, these data provide convincing evidence that ICAM-4 is critical in erythroblastic island formation via ICAM-4/alpha V adhesion and also demonstrate that the novel experimental strategies we developed will be valuable in exploring molecular mechanisms of erythroblastic …

High voltage systems operated in vacuum require insulating materials to maintain spacing between conductors held at different potentials, and may be used to maintain a nonconductive vacuum boundary. Traditional vacuum insulators generally consist of a single material, but insulating structures composed of alternating layers of dielectric and metal can also be built. These ''High-Gradient Insulators'' have been experimentally shown to withstand higher voltage gradients than comparable conventional insulators. As a result, they have application to a wide range of high-voltage vacuum systems where compact size is important. This paper describes ongoing research on these structures, as well as the current theoretical understanding driving this work.

Environmental estrogens are environmental contaminants that can mimic the biological activities of the female hormone estrogen in the endocrine system, i.e. they act as endocrine disrupters. Several substances are reported to have estrogen-like activity or estrogenic activity. These include steroid hormones, synthetic estrogens (xenoestrogens), environmental pollutants and phytoestrogens (plant estrogens). Using the chromogenic substrate ortho-nitrophenyl-{beta}-D-galactopyranoside (ONPG) we show that an estrogen-sensitive yeast strain RMY/ER-ERE, with human estrogen receptor (hER{alpha}) gene and the lacZ gene which encodes the enzyme {beta}-galactosidase, is able to detect estrogenic activity in water samples over a wide range of spiked concentrations of the hormonal estrogen 17{beta}-estradiol (E2). Ortho-nitrophenol (ONP), the yellow product of this assay can be detected using spectrophotometry but requires cell lysis to release the enzyme and allow product formation. We improved this aspect in a fluorogenic assay by using fluorescein di-{beta}-D-galactopyranoside (FDG) as a substrate. The product was visualized using fluorescence microscopy without the need to kill, fix or lyse the cells. We show that in live yeast cells, the uptake of E2 and the subsequent production of {beta}-galactosidase enzyme occur quite rapidly, with maximum enzyme-catalyzed fluorescent product formation evident after about 30 minutes of exposure to E2. The fluorogenic assay was applied …

The conditions under which optical materials are susceptible to laser-induced damage is a topic which has been the subject of considerable study. Laser parameters such as wavelength and temporal pulse duration have been studied extensively. Until this work the effect of temporal pulse shape has not been considered. We present here data from a simple single-parameter model and a supporting experiment which predicts that a Flat-In-Time-pulse will produce damage at approximately 80% of the fluence of a Gaussian pulse of the same FWHM duration.

Novel Bi{sub 2}S{sub 3} nanostructures with a sheaf-like morphology are obtained via reaction of bismuth acetate-oleic acid complex with elemental sulfur in 1-octadecence. We propose these structures form by the splitting crystal growth mechanism, which is known to account for the morphology some mineral crystals assume in nature. By controlling the synthetic parameters, different forms of splitting, analogous to observed in minerals, are obtained in our case of Bi{sub 2}S{sub 3}. These new and complex Bi{sub 2}S{sub 3} nanostructures are characterized by TEM, SEM, XRD and ED.

We present an expression for the leading-color (planar) four-loop four-point amplitude of N = 4 supersymmetric Yang-Mills theory in 4-2{epsilon} dimensions, in terms of eight separate integrals. The expression is based on consistency of unitarity cuts and infrared divergences. We expand the integrals around {epsilon} = 0, and obtain analytic expressions for the poles from 1/{epsilon}{sup 8} through 1/{epsilon}{sup 4}. We give numerical results for the coefficients of the 1/{epsilon}{sup 3} and 1/e{sup 2} poles. These results all match the known exponentiated structure of the infrared divergences, at four separate kinematic points. The value of the 1/{epsilon}{sup 2} coefficient allows us to test a conjecture of Eden and Staudacher for the four-loop cusp (soft) anomalous dimension. We find that the conjecture is incorrect, although our numerical results suggest that a simple modification of the expression, flipping the sign of the term containing {zeta}{sub 3}{sup 2}, may yield the correct answer. Our numerical value can be used, in a scheme proposed by Kotikov, Lipatov and Velizhanin, to estimate the two constants in the strong-coupling expansion of the cusp anomalous dimension that are known from string theory. The estimate works to 2.6% and 5% accuracy, providing non-trivial evidence in support of the …

A search for lepton flavor violating decays of the {tau} lepton to a lighter mass lepton and a pseudoscalar meson has been performed using 339 fb{sup -1} of e{sup +}e{sup -} annihilation data collected at a center-of-mass energy near 10.58GeV by the BABAR detector at the SLAC PEP-II storage ring. No evidence of signal has been found, and upper limits on the branching fractions are set at 10{sup -7} level.

The new barrel Instrumented Flux Return (IFR) of BABAR detector will be reported here. Limited Streamer Tubes (LSTs) have been chosen to replace the existing RPCs as active elements of the barrel IFR. The layout of the new detector will be discussed: in particular, a cell bigger than the standard one has been used to improve efficiency and reliability. The extruded profile is coated with a resistive layer of graphite having a typical surface resistivity between 0.2 and 0.4 MOhm/square. The tubes are assembled in modules and installed in 12 active layers of each sextant of the IFR detector. R&amp;D studies to choose the final design and Quality Control procedure adopted during the tube production will be briefly discussed. Finally the performances of installed LSTs into 2/3 of IFR after 8 months of operations will be reported.

The authors report the discovery of a cluster-scale lensed quasar, SDSS J1029+2623, selected from the Sloan Digital Sky Survey. The lens system exhibits two lensed images of a quasar at z{sub s} = 2.197. The image separation of 22.5 makes it the largest separation lensed quasar discovered to date. The similarity of the optical spectra and the radio loudnesses of the two components support the lensing hypothesis. Images of the field show a cluster of galaxies at z{sub l} {approx} 0.55 that is responsible for the large image separation. The lensed images and the cluster light center are not collinear, which implies that the lensing cluster has a complex structure.

We examine the production and evolution of microscopic black holes in the early universe in the large extra dimensions scenario. We demonstrate that, unlike in the standard four-dimensional cosmology, in large extra dimensions absorption of matter from the primordial plasma by the black holes is significant and can lead to rapid growth of the black hole mass density. This effect can be used to constrain the conditions present in the very early universe. We demonstrate that this constraint is applicable in regions of parameter space not excluded by existing bounds.