Search

It has long been recognized that broadband laser light has the potential to control parametric instabilities in inertial-confinement-fusion (ICF) plasmas. Here, we use results from laser-plasma-interaction simulations to estimate the bandwidth requirements for mitigating the three predominant classes of instabilities in direct-drive ICF implosions: cross-beam energy transfer (CBET), two-plasmon decay (TPD), and stimulated Raman scattering (SRS). We find that for frequency-tripled, Nd:glass laser light, a bandwidth of 8.5 THz can significantly increase laser absorption by suppressing CBET, while ∼13 THz is needed to mitigate absolute TPD and SRS on an ignition-scale platform. None of the glass lasers used in contemporary ICF experiments, however, possess a bandwidth greater than 1 THz and reaching larger values requires the use of an auxiliary broadening technique such as optical parametric amplification or stimulated-rotational-Raman scattering. An arguably superior approach is the adoption of an argon-fluoride (ArF) laser as an ICF driver. Besides having a broad bandwidth of ∼10 THz, the ArF laser also possesses the shortest wavelength (193 nm) that can scale to the high energy/power required for ICF—a feature that helps to mitigate parametric instabilities even further. We show that these native properties of ArF laser light are sufficient to eliminate nearly all CBET scattering in a direct-drive target and also raise absolute TPD and SRS thresholds well above those for broadband glass lasers. The effective control of parametric instabilities with broad bandwidth is potentially a “game changer” in ICF because it would enable higher laser intensities and ablation pressures in future target designs.

The success of direct laser-driven inertial confinement fusion (ICF) relies critically on the efficient coupling of laser light to plasma. At ignition scale, the absolute stimulated Raman scattering (SRS) instability can severely inhibit this coupling by redirecting and strongly depleting laser light. This article describes a new dynamic saturation regime of the absolute SRS instability near one-quarter of the critical density. The saturation occurs when spatiotemporal ion-acoustic fluctuations in the plasma density detune the instability resonance. The dynamic saturation mitigates the strong depletion of laser light and enhances its transmission through the instability region, explaining the coupling of laser light to ICF targets at higher plasma densities.

Multibeam absolute instability thresholds for stimulated Raman scattering (SRS) and two-plasmon decay (TPD) are calculated in three dimensions for conditions relevant to direct-drive inertial confinement fusion experiments on the OMEGA laser and at the National Ignition Facility (NIF). Although multibeam effects are found to be significant for both instabilities, SRS is found to have less efficient multibeam coupling than TPD. The results are consistent with the observation of a TPD-dominated regime on the OMEGA laser and a SRS-dominated regime on the NIF despite the single-beam SRS threshold being lower than the single-beam TPD threshold on both facilities. The minimum instability threshold for NIF plasma parameters occurs for SRS near quarter-critical densities with a shared electromagnetic wave propagating along the beam axis.

Thresholds for the absolute stimulated Raman scattering (SRS) and two-plasma decay (TPD) instabilities driven by multiple broadband laser beams are evaluated using 3D simulations at conditions relevant to inertial confinement fusion experiments. Multibeam TPD and SRS backscatter are found to be easier to mitigate with bandwidth than the corresponding single-beam instabilities. A relative bandwidth of 1% increases the threshold for absolute SRS backscatter by a factor of 4 at conditions relevant to ongoing National Ignition Facility experiments and should be sufficient to keep all of the absolute instabilities below threshold in experiments with similar conditions.

Close tidal encounters among large planetesimals and moons should have been more common than grazing or normal impacts. Using a mass spring model within an N-body simulation, we simulate the deformation of the surface of an elastic spherical body caused by a close parabolic tidal encounter with a body that has similar mass as that of the primary body. Such an encounter can induce sufficient stress on the surface to cause brittle failure of an icy crust and simulated fractures can extend a large fraction of the radius of body. Strong tidal encounters may be responsible for the formation of long graben complexes and chasmata in ancient terrain of icy moons such as Dione, Tethys, Ariel and Charon., accepted for publication in Icarus, for a movie see https://youtu.be/W5GyTEyXTss

The scattering of laser light due to cross-beam energy transfer (CBET) is an undesirable process in direct-drive inertial confinement fusion (ICF) that degrades both the compression and symmetry of the imploding target. Here, we present results from laser-plasma interaction simulations performed with the wave-based code LPSE that explore two techniques for suppressing CBET in frequency-tripled, Nd:glass laser beams crossing in a transonic plasma: a.) frequency detuning using two or three discrete “colors” of narrowband laser light; and b.) broad laser bandwidth. We find that for beams modeled with random speckle patterns, distributed phase plates and polarization smoothing, and for plasma conditions similar to those on the National Ignition Facility, the former method reduces CBET to an extent, but the degree of mitigation plateaus once the frequency separation greatly exceeds the resonance width of the CBET instability. Broadband lasers, on the other hand, are predicted to suppress CBET completely at a bandwidth of about 8 THz (Δ ω/ω0 ≃ 1%, where Δ ω/2π and ω0 are the laser bandwidth and angular frequency, respectively) for the same conditions. Although the Nd:glass lasers used for ICF research today have bandwidths far below this value, the spectra from such lasers could likely be broadened to multi-terahertz levels by utilizing stimulated rotational Raman scattering in a gaseous diatomic medium. Alternatively, the required bandwidth could be obtained with an excimer laser driver such as argon-fluoride, which has a native bandwidth in excess of 7 THz. Either of these two options would enable higher and more symmetric ablation pressures in future, direct-drive, ICF target designs.

Cross-beam energy transfer (CBET) is a laser-plasma instability that significantly impacts laser energy deposition in laser-driven inertial confinement fusion (ICF) experiments. Radiation-hydrodynamics simulations, which are used to design and tune ICF implosions, use ray-based CBET models, but existing models require artificial multipliers to conserve energy and to obtain quantitative agreement with experiments. The discretization of the ray trajectories in traditional ray-based CBET models does not account for the rapid variation in CBET gain as rays pass through caustics. We introduce a model that allows one to treat caustics much more accurately and greatly improves energy conservation. The ray-based CBET calculations show excellent agreement with laser absorption from two-dimensional wave-based calculations (0.3% difference) and a three-dimensional 60-beam OMEGA implosion (2.4% difference) without artificial multipliers.

Three-dimensional laser-plasma interaction simulations show that laser frequency detuning by an amount achievable with current laser technology can be used to suppress the two-plasmon decay (TPD) instability and the corresponding hot-electron generation. For the plasma conditions and laser configuration in a direct-drive inertial confinement fusion implosion on the OMEGA laser, the simulations show that $\ensuremath{\sim}0.7%$ laser frequency detuning is sufficient to eliminate TPD-driven hot-electron generation in current experiments. This allows for higher ablation pressures in future implosion designs by using higher laser intensities.

Cross-beam energy transfer (CBET) is a significant energy-loss mechanism in directly driven inertial-confinement-fusion (ICF) targets. One strategy for mitigating CBET is to increase the bandwidth of the laser light, thereby disrupting the resonant three-wave interactions that underlie this nonlinear scattering process. Here, we report on numerical simulations performed with the wave-based code lpse that show a significant reduction in CBET for bandwidths of 2-5 THz (corresponding to a normalized bandwidth of 0.2%-0.6% at a laser wavelength of 351nm) under realistic plasma conditions. Such bandwidths are beyond those available with current high-energy lasers used for ICF, but could be achieved using stimulated rotation Raman scattering in diatomic gases like nitrogen.

Transposon mutagenesis was used to isolate insertion mutants of the photosynthetic bacterium Rhodobacter capsulatus which were unable to grow under aerobic conditions in the dark on malate, succinate or fumarate as sole carbon sources. Of five mutants isolated, all were deficient in C

The new component of the “laser–plasma simulation environment” (LPSE) described here is a practical numerical model that solves the coupled vector equations for the propagation of nearly monochromatic, coherent, electromagnetic waves in inhomogeneous unmagnetized plasmas. It operates efficiently in the numerically challenging semiclassical regime where characteristic plasma scale lengths are many times greater than the wavelength of the light and solutions are highly oscillatory. Solutions can be obtained in one, two, or three spatial dimensions and time. The model includes the effects of nonlinear coupling of electromagnetic waves to the low-frequency plasma perturbations (i.e., ion-acoustic response) that are responsible for stimulated Brillouin scattering. Induced plasma perturbations are assumed to be imposed on a prescribed large-scale inhomogeneous background that includes spatially varying plasma density and flow. Our code is directly relevant to the problem of cross-beam energy transfer in laser-driven inertial confinement fusion. It may also be applicable in other areas where eikonal solutions of multicomponent wave equations (or coupled wave equations) are insufficient, such as optical scattering from ultrasound, electron dynamics in quantum devices or in nanoscale light–matter interactions.

Absolute instability thresholds for stimulated Raman scattering (SRS) and two-plasmon decay (TPD) driven by a broadband laser pulse are evaluated numerically. The scalings of the calculated thresholds with the density scale length, temperature, and central wavelength are qualitatively similar to the existing analytical results. The threshold values, however, exhibit significant quantitative differences. Comparisons between the thresholds calculated for various broadband power spectra indicate a universal scaling of the threshold intensity with laser coherence time (τc). For SRS, Ithr∝τc−1/3, and for TPD, Ithr∝τc−1/2.

Neisseria meningitidiscan utilize haem, haemoglobin and haemoglobin–haptoglobin complexes as sources of iron via two TonB-dependent phase variable haemoglobin receptors, HmbR and HpuAB. HmbR is over-represented in disease isolates, suggesting a link between haemoglobin acquisition and meningococcal disease. This study compared the distribution of HpuAB and phase variation (PV) status of both receptors in disease and carriage isolates. Meningococcal disease (n = 214) and carriage (n = 305) isolates representative of multiple clonal complexes (CCs) were investigated for the distribution, polyG tract lengths and ON/OFF status of both haemoglobin receptors, and for the deletion mechanism for HpuAB. Strains with both receptors or onlyhmbRwere present at similar frequencies among meningococcal disease isolates as compared with carriage isolates. However, >90 % of isolates from the three CCs CC5, CC8 and CC11 with the highest disease to carriage ratios contained both receptors. Strains with anhpuAB-only phenotype were under-represented among disease isolates, suggesting selection against this receptor during systemic disease, possibly due to the receptor having a high level of immunogenicity or being inefficient in acquisition of iron during systemic spread. Absence ofhpuABresulted from either complete deletion or replacement by an insertion element. In an examination of PV status, one or both receptors were found in an ON state in 91 % of disease and 71 % of carriage isolates. We suggest that expression of a haemoglobin receptor, either HmbR or HpuAB, is of major importance for systemic spread of meningococci, and that the presence of both receptors contributes to virulence in some strains.

Broad bandwidth, infrared light sources have the potential to revolutionize inertial confinement fusion (ICF) by suppressing laser-plasma instabilities. There is, however, a tradeoff: The broad bandwidth precludes high efficiency conversion from the infrared to the ultraviolet, where laser-plasma interactions are weaker. Operation in the infrared could intensify the role of resonance absorption, an effect long suspected to be the shortcoming of early ICF experiments. Here, we present simulations exploring the effect of the bandwidth on resonance absorption. In the linear regime, the bandwidth has little effect on resonance absorption; in the nonlinear regime, the bandwidth suppresses enhanced absorption resulting from the electromagnetic decay instability. These findings evince that, regardless of the bandwidth, an ICF implosion will confront at least linear levels of resonance absorption.

A study has been made of the pyrolysis of different cottons in vacuum, and in dry air, mainly at 418°C and the products have been fractionated and analysed. From a purified cotton cellulose, the main products are a combustible tar and water, but when a flame-retardant is present less tar and more gas and carbonaceous residue (char) are produced. The tar is highly flammable, and is a major factor in the burning of cotton. There is a correlation between the amount of tar formed and the flammability of the cotton. Removal of the impurities from the cotton cellulose leads to the formation of more tar on pyrolysis. The tar is a mixture of organic compounds of which the major component is laevoglucosan. Acids, carbonyl compounds and unsaturated compounds have been found and determined quantitatively. It is concluded that for a treated cotton cellulose material to be flame-resistant the amount of tar formed on pyrolysis must be small.

Radiation-hydrodynamic simulations of inertial confinement fusion (ICF) experiments rely on ray-based cross-beam energy transfer (CBET) models to calculate laser-energy deposition. The ray-based models assume locally plane-wave laser beams and polarization-averaged incoherence between laser speckles for beams with polarization smoothing. The impact of beam speckle and polarization smoothing on CBET are studied using the 3-D wave-based laser–plasma interaction code LPSE. The results indicate that ray-based models underpredict CBET when the assumption of spatially averaged longitudinal incoherence across the CBET interaction region is violated. A model for CBET between linearly polarized speckled beams is presented that uses ray tracing to solve for the real speckle pattern of the unperturbed laser beams within the eikonal approximation and gives excellent agreement with the wave-based calculations. OMEGA-scale 2-D LPSE calculations using ICF-relevant plasma conditions suggest that the impact of beam speckl...

Multibeam experiments relevant to direct-drive inertial confinement fusion show the importance of nonlinear saturation mechanisms in the common-wave two-plasmon-decay (TPD) instability. Planar-target experiments on the OMEGA laser used hard x-ray measurements to study the influence of the linear common-wave growth rate on TPD-driven hot-electron production in two drive-beam configurations and over a range of overlapped laser intensities from 3.6 to 15.2 × 1014 W/cm2. The beam configuration with the larger linear common-wave growth rate had a lower intensity threshold for the onset of hot-electron production, but the linear growth rate made no significant impact on hot-electron production at high intensities. The experiments were modeled in 3-D using a hybrid code LPSE (laser plasma simulation environment) that combines a wave solver with a particle tracker to self-consistently calculate the electron velocity distribution and evolve electron Landau damping. Good quantitative agreement was obtained between ...

The effects of frequency detuning laser beams in direct-drive symmetric implosions were investigated with a 3-D cross-beam energy transfer (CBET) model. The model shows that interactions between beams with relative angles between 45° and 90° are most significant for CBET in OMEGA direct-drive implosions. There is no net exchange in power between beams, but there is significant redistribution of power from the ingoing central portion of the beam profile to the outgoing edge as it is exiting the plasma, reducing the total absorbed power. Redistribution of laser power because of CBET increased the root-mean-square (rms) absorption nonuniformity by an order of magnitude. CBET mitigation by shifting relative wavelengths of three groups of laser beams fed by each of the different beamlines was modeled. At an on-target wavelength shift of Δλ ∼ 10 A, the total laser absorption was maximized, and the rms absorption nonuniformity was near minimum. To completely decouple the three groups of beams from each other req...

Cross-beam energy transfer (CBET) is thought to be responsible for a 30% reduction in hydrodynamic coupling efficiency on OMEGA and up to 50% at the ignition scale for direct-drive (DD) implosions. These numbers are determined by ray-based models that have been developed and integrated within the radiation–hydrodynamics codes LILAC (1-D) and DRACO (2-D). However, ray-based modeling of CBET in an inhomogeneous plasma assumes a steady-state plasma response, does not include the effects of beam speckle, and treats ray caustics in an ad hoc manner. The validity of the modeling for ignition-scale implosions has not yet been determined. To address the physics shortcomings, which have important implications for DD inertial confinement fusion, a new wave-based model has been developed. It solves the time-enveloped Maxwell equations in three dimensions, including polarization effects, plasma inhomogeneity, and open-boundary conditions with the ability to prescribe beams incident at arbitrary angles. Beams can be m...

Computer simulations of a flow of charged particles driven with a travelling electrostatic wave along a flat solid boundary were performed. Many-particle flows of this kind are shown to exhibit self-consistent behaviour practically independent of the initial particle conditions. The average macroscopic velocity of the flow results from the interplay of the driving field and the interactions in the system. This velocity can take any value between zero and the wave phase velocity and may even become negative (directed opposite to the wave propagation). The average velocity in the intermediate regime flows is achieved through the scattering of particles between different velocity states.

A search for the first region in the genomic RNA of a potyvirus to be encapsidated during the assembly of virus particles in vivo has been undertaken. Protoplasts were collected at various times after inoculation and fragments of viral RNA that were protected from nuclease degradation were isolated from extracts and identified by RT-PCR procedures. Nuclease-resistant fragments of viral RNA were not detected in protoplasts that had been infected for 30 min. However, such fragments were present in protoplasts collected 40 min after inoculation and these contained a region at or near the 5' terminus of the viral RNA. Protoplasts that had been infected for 45 min or longer contained full-length viral RNA in a nuclease-resistant form. These results suggest that assembly of virus particles begins with the interaction of coat protein subunits with the 5' terminal region of progeny viral RNA molecules.

We have reanalyzed the structure of the gamma T-15 peptide from the minor M gamma chain of human hemoglobin (Hb) F. Amino acid analysis confirmed that the Leu 141 residue was missing from position 9 of this peptide, and liquid secondary ion mass spectrometry indicated that it was replaced, not by methionine (residue mass 131) as previously believed, but by an amino acid of mass 129. By analogy with the recently reported oxidation of the corresponding leucine at position gamma 141 of the unstable Hb Atlanta, it appears that the M gamma chain also results from the oxidation of gamma 141 to hydroxyleucine (residue mass 129). The finding that the proportion of the M gamma chain increased when red cell lysates were prepared with carbon tetrachloride prompted us to reinvestigate the oxidation mechanism involved in the formation of beta 141 hydroxyleucine in Hb Atlanta. Oxidation of the beta 141 residue could be detected when carbon tetrachloride was used in the lysis protocol, while conversion of oxyhemoglobin to carbon monoxyhemoglobin prior to carbon tetrachloride treatment prevented oxidation. It therefore appears that the hydroxylation of Leu 141 is not an in vivo process in the circulating red cell. Perhaps leucine at position 141 of the beta, gamma, and delta chains (and at position 136 of the alpha chain), which forms a contact with heme and is located directly across the heme plate from the E helix, is oxidized to hydroxyleucine at a very low rate forming minute amounts of modified chains; this process is accelerated by treatment with agents such as carbon tetrachloride and prolonged exposure to air.

The recent report of the oxidation of beta 141 Leu in a New Zealand family with Hb Atlanta [ beta 75(E19)Leu--Pro] prompted us to reinvestigate the original Hb Atlanta case from Georgia. Tryptic peptide maps showed that the modified beta CoT-14 peptide was present together with beta AT-14 in isopropanol precipitates of Hb Atlanta. Amino acid analysis confirmed that beta CoT-14 lacked leucine and mass spectrometry indicated that it had an increased mass of 16 Daltons. These findings support the proposition that the beta 75 Leu--Pro substitution in the E helix is the direct cause of the beta 141 Leu oxidation.

As technology corporations migrate toward an integrated systems approach to product development, emphasis must be paid to the creation and infrastructure of the environment as well as the tools and information that must coexist to support design synthesis. This paper details a coherent approach towards integration of existing and emerging computing technologies to create the design environment. This environment captures contemporary elements of supercomputing, visualization, networking, scalable parallel network computing, and visual programming, to provide a heterogeneous platform in support of computational prototyping.

Authors Robert L. Boyle, Jr., M.P.H., FACMPE, James G. Shaw, M.B.A., and Diane Stewart describe how to put a quality improvement program into practice by identifying key internal processes, selecting an improvement program, identifying what to improve and developing a review method. They also present results from the first year of their quality improvement process.

We have reanalyzed the structure of the gamma T-15 peptide from the minor M gamma chain of human hemoglobin (Hb) F. Amino acid analysis confirmed that the Leu 141 residue was missing from position 9 of this peptide, and liquid secondary ion mass spectrometry indicated that it was replaced, not by methionine (residue mass 131) as previously believed, but by an amino acid of mass 129. By analogy with the recently reported oxidation of the corresponding leucine at position gamma 141 of the unstable Hb Atlanta, it appears that the M gamma chain also results from the oxidation of gamma 141 to hydroxyleucine (residue mass 129). The finding that the proportion of the M gamma chain increased when red cell lysates were prepared with carbon tetrachloride prompted us to reinvestigate the oxidation mechanism involved in the formation of beta 141 hydroxyleucine in Hb Atlanta. Oxidation of the beta 141 residue could be detected when carbon tetrachloride was used in the lysis protocol, while conversion of oxyhemoglobin to carbon monoxyhemoglobin prior to carbon tetrachloride treatment prevented oxidation. It therefore appears that the hydroxylation of Leu 141 is not an in vivo process in the circulating red cell. Perhaps leucine at position 141 of the beta, gamma, and delta chains (and at position 136 of the alpha chain), which forms a contact with heme and is located directly across the heme plate from the E helix, is oxidized to hydroxyleucine at a very low rate forming minute amounts of modified chains; this process is accelerated by treatment with agents such as carbon tetrachloride and prolonged exposure to air.

The kinetics of ligand binding to the periplasmic C4-dicarboxylate binding protein (DctP) from Rhodobacter capsulatus were investigated by exploiting the changes in the intrinsic fluorescence of the protein upon binding ligands. Steady state measurements have shown that L-malate, succinate, and fumarate are all bound with sub-micromolar Kd values, whereas D-malate is bound 2 orders of magnitude more weakly. Stopped-flow studies have revealed that the binding process involves at least three steps. In the absence of ligand, the protein is in equilibrium between an essentially nonbinding form, BP1, and the binding form, BP2. Ligands bind to the BP2 form, shifting the equilibrium toward the BP2-L conformation, and also inducing a further isomerization of the protein, to the BP3-L form. The kinetic properties of the four different conformational states of the DctP protein identified in this study would be consistent with their identification as the closed-conformation, the open-conformation, an open-liganded conformation, and a closed-liganded conformation. The latter three states have been identified by x-ray crystallographic studies of binding proteins, but no kinetic or structural data have been presented previously to support the possibility of a closed but unliganded conformation.

Transient measurements of the source-drain current ISD of amorphous silicon (a-Si:H) thin film transistors are compared with the results of two dimensional simulations. In particular, we have investigated the effect of different amorphous silicon layer thicknesses on the transient response. It is found that the dynamic response of a transistor with 0.4 μm a-Si:H is significantly slower than that of a device with only 0.06 μm of a-Si:H.

Parents and teachers of 20 children with developmental delays, 24 through 38 months of age, from an early education program in Columbus, Ohio, were interviewed using the Adaptive Behavior Scale for Infants and Early Childhood. Significant differences were found between some of the ratings over the 23 domain and 11 subdomain scores, specifically in regard to sex of the child and length of time of the child's participation in the program. Parents provided higher ratings than did teachers on some domains. In general, parents and teachers tended to agree on the overall adaptive functional levels.

We have developed a numerical simulation program (MANIFEST) which calculates the time-dependent behaviour of one and two dimensional amorphous silicon devices. Our model solves the complete set of transport equations for both electrons and holes and fully includes the appropriate time dependent occupation functions for the traps in the band gap of the amorphous silicon. These traps are assumed to obey Shockiey-Read-Hall kinetics. We have simulated the transient behaviour of pin and nin diodes, both in the dark and under illumination, as well as the characteristics of thin film transistors. Our initial results are in good agreement with experimental data.

The uncoating of tobacco mosaic virus (TMV) particles in protoplasts isolated from leaves of transgenic tobacco plants that express the TMV coat protein gene was investigated. Extracts of these protoplasts collected up to 1 hr after inoculation with TMV contained fewer of the complexes (“striposomes”) thought to be involved in cotranslational disassembly of virus particles than did extracts of protoplasts that do not express the viral coat protein gene. These results are consistent with the hypothesis that TMV coat protein-mediated resistance is at least in part the result of inhibition of the uncoating of the virus particles in the inoculum.

Transposon mutagenesis was used to isolate insertion mutants of the photosynthetic bacterium Rhodobacter capsulatus which were unable to grow under aerobic conditions in the dark on malate, succinate or fumarate as sole carbon sources. Of five mutants isolated, all were deficient in C4-dicarboxylate transport. However, these mutants were still capable of photoheterotrophic growth, although at a slower rate than the wild type, on malate and succinate (but not fumarate). The mutated locus (designated dct) was complemented in trans using a cosmid gene bank. Subcloning and complementation analysis indicated that at least three closely linked genes essential for aerobic dicarboxylate transport were contained within an 8.3 kb region of the Rhodobacter capsulatus chromosome.

The course of infection with tobacco vein mottling potyvirus (TVMV) in tobacco protoplasts and leaves was studied by electron microscopy with immunogold labeling. In sections of protoplasts inoculated with TVMV RNA 10, 21, or 45 h prior to fixation, antibodies to TVMV coat protein (CP) were bound to cylindrical inclusions and individual virions usually associated with these inclusions. Also, in sections of leaves from plants inoculated with TVMV 5, 14, or 21 days prior to fixation, antibodies to TVMV CP were bound to cylindrical inclusions and aggregates of virions in the cytoplasm [...]

The development of cylindrical inclusions in tobacco mesophyll protoplasts infected with the potyvirus tobacco vein mottling virus (TVMV) was examined. Bundles and pinwheels were observed in ultrathin sections of protoplasts collected 15−30 h after inoculation. In sections subjected to immunogold labeling with anti-TVMV cylindrical inclusion protein serum and gold-conjugated Protein A, the cylindrical inclusion protein was detected as early as 10 H after inoculation

In this paper we present results of two-dimensional numerical simulations of both amorphous silicon and NMOS and PMOS polycrystalline silicon thin-film transistors. Both types of devices are modeled using an effective medium approach whereby the defects and grain boundaries in the material are treated as a spatially uniform density of localized states in the band gap. The field-effect mobility is self-consistently calculated from the appropriate band mobility and using one set of parameters for each material we obtain very good agreement between simulations of both output and transfer characteristics and experimental data. The experimental activation energy of the source-drain current for the polycrystalline devices is also found to be in excellent agreement with the numerical simulations.

Aqueous emulsions of 21 insect growth regulators were tested for juvenile hormone activity against 1st-molt Aonidiella aurantii (Maskell) by spraying emulsions on the scale insects while these fed on lemon fruit. Residues of the 1st 6 available compounds were tested by spraying emulsions of these on lemon fruit and introducing crawlers onto the fruit 10 h later. These same compounds used to develop a method of testing by exposing white cap, 1st molt, 2nd molt, and adult stages of scales to their activity. Of these, mixed stereoisomers of methyl 10, ll-epoxy-7-ethyl-3,4-dimethyl-2,6-tridecadienoate and 6, 7-epoxy-3,7-dimethyl-l-[3,4-(methylenedioxy)phenoxy]-2-nonene were the most active (inhibited adult eclosion and prevented embryogenesis) at concentrations of 0.1 and 1.0%. The latter compound also inhibited adult eclosion of progeny from female treated with these concentrations 5 days after mating and suppressed the production of sex pheromone in virgin females treated in the 2nd molt with concentrations of 0.2 or 0.5%. Males were 16 times more susceptible to the activity of methoprene than females.

The NOVA laser has completed its first year of operation. During this period, emphasis has been placed on activation of the facility and of the numerous target and beam diagnostics. Two separate target chambers are in use. NOVA operation is separated into two broad functions: laser operations and experiments. The operations group provides the laser system control, operation, and data acquisition and the experiments group provides experiment definition, diagnostic instrumentation, and overall data processing. On the operations side, VAX 11/780 computers are used to set up diagnostic operating parameters and collect data recorded by the CAMAC and CCD modules. These data are delivered in files by electronic link to the Laser Experiments and Analysis Facility (LEAF) VAX 11/785 of the experiments group for processing. Film data are digitized at LEAF and the film data files are also processed on the LEAF VAX. The LEAF provides collection, processing, analysis, and archiving of the experimental data. The many applications software packages written for LEAF provide the experimental physicists and NOVA operations staff with programs and data bases for interpretation of experimental results. This software makes fundamental use of the ORACLE relational data base management system to both access the required data andmore » archive the obtained results. Post-shot data processing produces sets of scalar values, x-italic, y-italic profiles and x-italic, y-italic, z-italic contour data. The scalar data are stored in the ORACLE DB; the more extensive results are stored in binary files on disk. All data forms are accessed by a comprehensive software system, the electronic SHOTBOOK, developed around the ORACLE DBMS.« less

We compared pulsed Doppler (PD) measurements of stroke volume (SV) and cardiac output (CO) as a function of work load with previously reported values that were obtained by standard invasive methods. Suprasternal notch measurements of Doppler-shifted frequency (delta f) were obtained from the ascending aorta and SV calculated with the Doppler equation and an independent measurement of aortic diameter. Motion artifacts were minimized with the aid of a restraining table cycle ergometer. Signal aliasing was accommodated with manual summation of delta f waveforms. A total of 207 determinations were made in 10 sitting subjects exercising to exhaustion. Linear regression analysis of CO vs. work load was significant (P less than 0.001). The correlation coefficient (r = 0.95) and standard error of estimate value (1.21 1/min) were similar to values from the literature. Absolute values of CO and SV underestimated the literature values across all work loads. Technical reproducibility was assessed by comparing with paired t tests the differences between 65 duplicate serial measurements of CO and SV at rest and exercise. No significant differences (P less than 0.001) were found. We concluded that PD-determined SV and CO are reproducible and correlate linearly with work load in a manner consistent with reported invasive techniques. Thus the PD method appears suitable for use during submaximal and peak exercise.

A 4-yr study on Valencia oranges near Fillmore, Ventura Co., California, indicated that a noninclusion virus disease was an important mortality factor in the suppression of populations of the citrus red mite, Panonychus citri (McGregor), at both high (16 mites/leaf) and relatively low (2–3/leaf) densities. The phytoseiid mite, Ambyseius hibisci (Chant), apparently played a complimentary but secondary role in suppressing mite populations in this study.

The presence of birefringent crystalline inclusions within the bodies of citrus red mites, Panonychus citri , infected with a nonoccluded virus is the major criterion for diagnosis. However, if mites inoculated with the virus are exposed to a high humidity within 5–6 days, the initiation of these crystals is greatly inhibited.

Adult male yellow scale, Aonidiella citrina (Coquillett), observed in the laboratory had a maximum lifespan of 18 h under continuous light. In the field, more males were collected on baited traps with mature virgin yellow scale when the traps were 2.4 m above ground on citrus trees. Maximum male flight activity occurred during the crepuscular hours, when light intensity was less than 5 lux. Males were collected in the field at temperatures ranging from 11.1 to 20.0°C; also, in the laboratory, males were inhibited from flying but not immobilized at 10°C. As temperatures were increased from 15.6 to 43.3°C, the number of males in flight increased. Virgin yellow scale females reared in the laboratory attracted native yellow scale males in the field. Marked yellow scale males released in a grove of mature navel orange trees were capable of flying at least 96 m upwind and 128 m downwind, in response to traps baited with attractive females.

An investigation of thermomigration in interstitial solid solutions of carbon in β-Ti, V, α-Fe, Co, Ni, and Pd has been carried out using a radioactive tracer technique. A substantial solute redistribution occurred towards the hotter regions in α-iron and vanadium and towards the colder regions in palladium whilst for Co, Ni and β-Ti very little segregation was observed. The measured heats of transport were (in kcal per g-atom): α-Fe, −14.1±1.5; V, −4.9±1.0; Pd, +8.4±1.5; Co, +1.5±1.5; Ni, −1.6±1.4; β-Ti, −1.0±1.0. An examination of the results obtained together with all of the published data for interstitial solute thermomigration suggests that electronic effects could be of major importance in determining the redistributions observed.