744 research outputs found

    Inheritance of resistance to blackeye cowpea mosaic and cowpea aphid-borne mosaic viruses in Phaseolus vulgaris

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    In populations from crosses of resistant and susceptible plants of the bean (Phaseolus vulgaris) cultivar Black Turtle Soup, resistance to blackeye cowpea mosaic virus (BICMV) and to cowpea aphidborne mosaic virus (CAbMV) was conferred independently by single dominant factors that appear to be closely linked. The symbol Bcm was assigned to the gene for BICMV resistance and Cam to that for CAbMV. Linkage was determined by separately inoculating plants of the testeross with both viruses on different leaves. Since BICMV and CAbMV Incite identical symptoms, but do not cross protect against each other, their presence in each susceptible plant was determined by enzyme-linked immunosorbent assay (ELISA). This detection method was highly specific because the two viruses are distantly related serologically. The normally resistant plants responded with a lethal systemic hypersensitive reaction when approach-grafted to BICMV or CAbMV-infected plants, or when mechanically in oculated and held constantiy at 35°

    Inheritance of resistance to blackeye cowpea mosaic virus in Vigna unguiculata

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    Abstract: Crosses between the resistant cowpea line TVU 2480 obtained from the International Institute of Tropical Agriculture (llTA), Ibadan, Nigeria and the susceptible domestic cultivar Early Ramshorn were used to determine the inheritance of resistance to blackeye cowpea mosaic virus (B1CMV). Evaluation of F1, F2, and reciprocal backcross populations by symptomatology and enzyme-linked immunosorbent assay (ELISA) clearly indicated that a single recessive gene controls the high level of resistance. The symbol bcm (blackeye cowpea mosaic) is assigned to this factor. llTA cowpea lines TVU 2740, TVU 3273, TVU 2657, and TVU 2845 seem to possess this same gen

    Absolute calibration of GafChromic film for very high flux laser driven ion beams.

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    We report on the calibration of GafChromic HD-v2 radiochromic film in the extremely high dose regime up to 100 kGy together with very high dose rates up to 7 × 1011 Gy/s. The absolute calibration was done with nanosecond ion bunches at the Neutralized Drift Compression Experiment II particle accelerator at Lawrence Berkeley National Laboratory (LBNL) and covers a broad dose dynamic range over three orders of magnitude. We then applied the resulting calibration curve to calibrate a laser driven ion experiment performed on the BELLA petawatt laser facility at LBNL. Here, we reconstructed the spatial and energy resolved distributions of the laser-accelerated proton beams. The resulting proton distribution is in fair agreement with the spectrum that was measured with a Thomson spectrometer in combination with a microchannel plate detector

    Experiment K-6-03. Gravity and skeletal growth, part 1. Part 2: Morphology and histochemistry of bone cells and vasculature of the tibia; Part 3: Nuclear volume analysis of osteoblast histogenesis in periodontal ligament cells; Part 4: Intervertebral disc swelling pressure associated with microgravity

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    Bone area, bone electrophysiology, bone vascularity, osteoblast morphology, and osteoblast histogenesis were studied in rats associated with Cosmos 1887. The results suggest that the synchronous animals were the only group with a significantly larger bone area than the basal group, that the bone electrical potential was more negative in flight than in the synchronous rats, that the endosteal osteoblasts from flight rats had greater numbers of transitional Golgi vesicles but no difference in the large Golgi saccules or the alkaline phosphatase activity, that the perioteal vasculature in the shaft of flight rats often showed very dense intraluminal deposits with adjacent degenerating osteocytes as well as lipid accumulations within the lumen of the vessels and sometimes degeneration of the vascular wall (this change was not present in the metaphyseal region of flight animals), and that the progenitor cells decreased in flight rats while the preosteoblasts increased compared to controls. Many of the results suggest that the animals were beginning to recover from the effects of spaceflight during the two day interval between landing and euthanasia; flight effects, such as the vascular changes, did not appear to recover

    A high resolution atlas of the galactic plane at 12 microns and 25 microns

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    High resolution images of the 12 micron and 25 micron IRAS survey data from each HCON crossing the Galactic Plane are being created for those regions that the original IRAS processing labeled as confused. This encompasses the area within 100 deg longitude of the Galactic Center and within 3 deg to 10 deg of the Plane. The procedures used to create the images preserve the spatial resolution inherent in the IRAS instrument. The images are separated into diffuse and point source components and candidate sources are extracted from the point source image after non-linear spatial sharpening. Fluxes are estimated by convolving the candidate sources with the point response function and cross-correlating with the original point source image. A source is considered real if it is seen on at least two HCON's with a rather generous flux match but a stringent position criterion. A number of fields spanning a range of source densities from low to high have been examined. Initial analysis indicates that the imaging and extraction works quite well up to a source density of about 100 sources per square degree or down to roughly 0.8 Janskys

    On production and asymmetric focusing of flat electron beams using rectangular capillary discharge plasmas

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    A method for the asymmetric focusing of electron bunches, based on the active plasma lensing technique is proposed. This method takes advantage of the strong inhomogeneous magnetic field generated inside the capillary discharge plasma to focus the ultrarelativistic electrons. The plasma and magnetic field parameters inside the capillary discharge are described theoretically and modeled with dissipative magnetohydrodynamic computer simulations enabling analysis of the capillaries of rectangle cross-sections. Large aspect ratio rectangular capillaries might be used to transport electron beams with high emittance asymmetries, as well as assist in forming spatially flat electron bunches for final focusing before the interaction point.Comment: 16 pages, 7 figures, 1 tabl

    Looking for CP Violation in W Production and Decay

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    We describe CP violating observables in resonant W±W^\pm and W±W^\pm plus one jet production at the Tevatron. We present simple examples of CP violating effective operators, consistent with the symmetries of the Standard Model, which would give rise to these observables. We find that CP violating effects coming from new physics at the TeVTeV scale could in principle be observable at the Tevatron with 10610^6 W±W^\pm decays.Comment: 15 pgs with standard LATEX, 7 ps figures embedded with eps

    Laser beam coupling with capillary discharge plasma for laser wakefield acceleration applications

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    One of the most robust methods, demonstrated up to date, of accelerating electron beams by laser-plasma sources is the utilization of plasma channels generated by the capillary discharges. These channels, i.e., plasma columns with a minimum density along the laser pulse propagation axis, may optically guide short laser pulses, thereby increasing the acceleration length, leading to a more efficient electron acceleration. Although the spatial structure of the installation is simple in principle, there may be some important effects caused by the open ends of the capillary, by the supplying channels etc., which require a detailed 3D modeling of the processes taking place in order to get a detailed understanding and improve the operation. However, the discharge plasma, being one of the most crucial components of the laser-plasma accelerator, is not simulated with the accuracy and resolution required to advance this promising technology. In the present work, such simulations are performed using the code MARPLE. First, the process of the capillary filling with a cold hydrogen before the discharge is fired, through the side supply channels is simulated. The main goal of this simulation is to get a spatial distribution of the filling gas in the region near the open ends of the capillary. A realistic geometry is used for this and the next stage simulations, including the insulators, the supplying channels as well as the electrodes. Second, the simulation of the capillary discharge is performed with the goal to obtain a time-dependent spatial distribution of the electron density near the open ends of the capillary as well as inside the capillary. Finally, to evaluate effectiveness of the beam coupling with the channeling plasma wave guide and electron acceleration, modeling of laser-plasma interaction was performed with the code INF&RNOComment: 11 pages, 9 figure

    A photometric redshift of z=1.80.3+0.4z=1.8^{+0.4}_{-0.3} for the \agile GRB 080514B

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    Aims: The AGILE gamma-ray burst GRB 080514B is the first burst with detected emission above 30 MeV and an optical afterglow. However, no spectroscopic redshift for this burst is known. Methods: We compiled ground-based photometric optical/NIR and millimeter data from several observatories, including the multi-channel imager GROND, as well as ultraviolet \swift UVOT and X-ray XRT observations. The spectral energy distribution of the optical/NIR afterglow shows a sharp drop in the \swift UVOT UV filters that can be utilized for the estimation of a redshift. Results: Fitting the SED from the \swift UVOT uvw2uvw2 band to the HH band, we estimate a photometric redshift of z=1.80.3+0.4z=1.8^{+0.4}_{-0.3}, consistent with the pseudo redshift reported by Pelangeon & Atteia (2008) based on the gamma-ray data. Conclusions: The afterglow properties of GRB 080514B do not differ from those exhibited by the global sample of long bursts, supporting the view that afterglow properties are basically independent of prompt emission properties.Comment: submitted to A&A letter
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