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Azolla filiculoides Lamarck (Azollaceae) (water fern), is an invasive floating macrophyte capable of rapid growth leading to the complete coverage of water surfaces. The North American weevil Stenopelmus rufinasus, Gyllenhal (Coleoptera: Curculionidae) is a biological control agent that has become naturalised in the UK. To determine the effects of the weevil on A. filiculoides in ‘semi-controlled’ conditions, weevils were introduced at four stocking densities into outdoor floating tanks containing A. filiculoides. The introduction of weevils at all densities resulted in a significant decline in percentage cover of A. filiculoides compared to the control. Increasing weevil stocking density resulted in a more rapid reduction in the area of green A. filiculoides. The highest stocking density of 400 weevils per m2 caused complete kill within a month of introduction. The UK summer provides conditions that are suitable for weevil reproduction and herbivory, and even the lowest stocking density of weevils tested (100 weevils per m2) can have a substantial impact on the surface cover of A. filiculoides. Although the weevil is effective in summer, augmentation is required annually for reliable control.

Winter cover cropping plays an important role in conservation farming. In the Midwest region of the USA, strips planted with Austrian winter peas [AWP (Pisum sativum L.)], radishes [RAD (Raphanus sativus L.)], and a mixed cover of both cultivars (MIX) were compared during the spring season to determine their impact on the soil quality at 0–5 and 5–10 cm depths. The treatments RAD, AWP, and MIX had the highest, intermediate, and lowest soil bulk density impacts (1·67, 1·52, and 1·50 Mg m−3, respectively). An opposite trend was observed for the concentrations of soil organic carbon (15·9, 17·6, and 19·4 g kg−1, respectively) and total nitrogen (1·5, 1·7, and 2·8 g kg−1, respectively), the calcium exchange capacity (8·6, 9·5, and 11·4 cmol+c kg−1, respectively), and earthworm density (85, 221 and 226 per m2 x 0·15 m, respectively). The AWP, MIX, and RAD resulted in the highest, intermediate, and lowest water stable aggregates (91·6, 87·4, and 79·9 per cent, respectively), mean weight diameter of aggregates (3·4, 2·7, and 2·1 mm, respectively), saturated hydraulic conductivity (15·7, 13·0, and 6·3 cm h−1, respectively), and intrinsic permeability (1·69, 1·37, and 0·70 cm2 10−10, respectively). The AWP and RAD treatments resulted in a similar C:N ratio (10·5), which was larger than associated with MIX (7·2). Overall, AWP and MIX had a larger positive impact on soil quality than RAD did, and the impact was greater at the 0–5 than the 5–10 cm depth. This indicates the suitability of the various cover crops for improving the soil quality and restoring geodiversity. Copyright © 2012 John Wiley & Sons, Ltd.

The compound Bi1/2Ag1/2TiO3 has been synthesized, for the first time, at 14−14.5 GPa and 1000 °C using the uniaxial split sphere anvil type press (USSA-2000). The structure of the quenched powder s...

A search for ${\ensuremath{\nu}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\ensuremath{\nu}}_{e}$ oscillations has been conducted at the Los Alamos Meson Physics Facility using ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ from ${\ensuremath{\pi}}^{+}$ decay in flight. An excess in the number of beam-related events from the ${\ensuremath{\nu}}_{e}\stackrel{\ensuremath{\rightarrow}}{C}{e}^{\ensuremath{-}}X$ inclusive reaction is observed. The excess is too large to be explained by normal ${\ensuremath{\nu}}_{e}$ contamination in the beam at a confidence level greater than 99%. If interpreted as an oscillation signal, the observed oscillation probability of $(2.6\ifmmode\pm\else\textpm\fi{}1.0\ifmmode\pm\else\textpm\fi{}0.5)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ is consistent with the previously reported ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\overline{\ensuremath{\nu}}}_{e}$ oscillation evidence from LSND.

A search for ${\ensuremath{\nu}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\ensuremath{\nu}}_{e}$ oscillations has been conducted with the LSND apparatus using ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ from ${\ensuremath{\pi}}^{+}$ decay in flight. Two analyses observe a total of 40 beam-on high-energy (60--200 MeV) electron events consistent with the ${\ensuremath{\nu}}_{e}\mathrm{C}\ensuremath{\rightarrow}{e}^{\ensuremath{-}}X$ inclusive reaction. This number is significantly above the $21.9\ifmmode\pm\else\textpm\fi{}2.1$ events expected from the ${\ensuremath{\nu}}_{e}$ contamination in the beam and the beam-off background. If interpreted as an oscillation signal, the observed oscillation probability of $(2.6\ifmmode\pm\else\textpm\fi{}1.0\ifmmode\pm\else\textpm\fi{}0.5)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ is consistent with the previously reported ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\overline{\ensuremath{\nu}}}_{e}$ oscillation evidence from LSND.

Summary‘Gulf Coast’, ‘Sharpblue’, and ‘Wannabe’ southern highbush blueberry (Vaccinium corymbosum interspecific hybrid) cultivars were planted at a density of 10,000 plants per ha in southwest Florida to test the feasibility of a non-dormant blueberry production system. A non-dormant production system involves application of nitrogen (N) throughout the fall and winter, which enables the plants to avoid the normal dormancy cycle and the concomitant chilling requirement. If successful, this system could extend the production range of blueberry into subtropical and tropical areas where chilling temperatures are inadequate for traditional (dormant) production systems. Nitrogen fertilizer rate (84 to 252 kg ha–1 N in year 1, 168 to 336 kg ha–1 N in year 2) was evaluated for effects on maintaining plant growth and development in this system. Additionally, since organic soil amendments are known to improve blueberry growth, the effects of municipal solid waste (MSW) compost and acidic peat on maintaining growth ...

Charged current scattering of ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ on ${}^{12}\mathrm{C}$ has been studied using a ${\ensuremath{\pi}}^{+}$ decay-in-flight ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ beam at the Los Alamos Meson Physics Facility. A sample of 56.8 $\ifmmode\pm\else\textpm\fi{}9.6$ events satisfying criteria for the exclusive reaction ${}^{12}{\mathrm{C}(\mathrm{\ensuremath{\nu}}}_{\mathrm{\ensuremath{\mu}}}{,\mathrm{\ensuremath{\mu}}}^{\mathrm{\ensuremath{-}}}{)}^{12}{\mathrm{N}}_{\mathrm{g}.\mathrm{s}.}$ was obtained using a large liquid scintillator neutrino detector. The observed flux-averaged cross section $(6.6\ifmmode\pm\else\textpm\fi{}1.0\ifmmode\pm\else\textpm\fi{}1.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}41}{\mathrm{cm}}^{2}$ agrees well with reliable theoretical expectations. A measurement was also obtained for the inclusive cross section to all accessible ${}^{12}\mathrm{N}$ states ${}^{12}\mathrm{C}({\ensuremath{\nu}}_{\ensuremath{\mu}},{\ensuremath{\mu}}^{\ensuremath{-}})X.$ This flux-averaged cross section is $(11.2\ifmmode\pm\else\textpm\fi{}0.3\ifmmode\pm\else\textpm\fi{}1.8)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}40}{\mathrm{cm}}^{2},$ which is approximately half of that given by a recent continuum random-phase approximation calculation.

Charged current reactions of nu_e on 12C have been studied using a mu decay-at-rest nu_e beam from the Los Alamos Meson Physics Facility. More than 500 events from the exclusive reaction 12C + nu_e -> e- + 12N g.s. were measured in a large Liquid Scintillator Neutrino Detector (LSND). The observed energy dependence of the cross section and the angular distribution of the outgoing electron agree well with theoretical expectations. Measurements are also presented for inclusive transitions to 12N excited states, 12C + nu_e -> e- + 12N and compared with theoretical expectations. Results are consistent with a recent Continuum Random Phase Approximation (CRPA) calculation.

No evidence for the neutrinoless double-{beta} decay of {sup 100}Mo has been found in a search using a segmented Si(Li) detector with source foils enriched to 97{percent} {sup 100}Mo. From an exposure of 0.2664 mole years, and using Bayesian statistics to calculate confidence levels, we find a 68{percent} lower limit on the half-life for the J{sup p}=0{sup +}{r_arrow}0{sup +} transition of 0.22{times}10{sup 23} yr. The measured half-life of the two neutrino double-{beta} decay is 0.76{sub {minus}0.14}{sup +0.22}{times}10{sup 19} yr. {copyright} {ital 1997} {ital The American Physical Society}

A search for nu_bar_mu to nu_bar_e oscillations has been conducted at the Los Alamos Meson Physics Facility using nu_bar_mu from mu+ decay at rest. The nu_bar_e are detected via the reaction (nu_bar_e,p) -> (e+,n), correlated with the 2.2 MeV gamma from (n,p) -> (d,gamma). The use of tight cuts to identify e+ events with correlated gamma rays yields 22 events with e+ energy between 36 and 60 MeV and only 4.6 (+/- 0.6) background events. The probability that this excess is due entirely to a statistical fluctuation is 4.1E-08. A chi^2 fit to the entire e+ sample results in a total excess of 51.8 (+18.7) (-16.9) (+/- 8.0) events with e+ energy between 20 and 60 MeV. If attributed to nu_bar_mu -> nu_bar_e oscillations, this corresponds to an oscillation probability (averaged over the experimental energy and spatial acceptance) of 0.0031 (+0.0011) (-0.0010) (+/- 0.0005)., 57 pages, 34 figures, revtex, additional information available at http://nu1.lampf.lanl.gov/~lsnd/

A search for ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\overline{\ensuremath{\nu}}}_{e}$ oscillations has been conducted at the Los Alamos Meson Physics Facility by using ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}$ from ${\ensuremath{\mu}}^{+}$ decay at rest. The ${\overline{\ensuremath{\nu}}}_{e}$ are detected via the reaction ${\overline{\ensuremath{\nu}}}_{e}p\ensuremath{\rightarrow}{e}^{+}n$, correlated with a $\ensuremath{\gamma}$ from $\mathrm{np}\ensuremath{\rightarrow}d\ensuremath{\gamma}$ ( $2.2\mathrm{MeV}$). The use of tight cuts to identify ${e}^{+}$ events with correlated $\ensuremath{\gamma}$ rays yields 22 events with ${e}^{+}$ energy between 36 and $60\mathrm{MeV}$ and only $4.6\ifmmode\pm\else\textpm\fi{}0.6$ background events. A fit to the ${e}^{+}$ events between 20 and $60\mathrm{MeV}$ yields a total excess of ${51.0}_{\ensuremath{-}19.5}^{+20.2}\ifmmode\pm\else\textpm\fi{}8.0$ events. If attributed to ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\overline{\ensuremath{\nu}}}_{e}$ oscillations, this corresponds to an oscillation probability of ( $0.31\ifmmode\pm\else\textpm\fi{}0.12\ifmmode\pm\else\textpm\fi{}0.05$)%.

The effect of annual compaction (1987-1989) of 9 and 18 Mg axle loads, and subsoiling for a corn/soybean rotation was investigated on a Hoytville silty clay loam (very poorly drained) soil. The effect on soil physical properties was also examined.

A search for ${\overline{\ensuremath{\nu}}}_{e}$'s in excess of the number expected from conventional sources has been made using the Liquid Scintillator Neutrino Detector, located 30 m behind the Los Alamos Meson Physics Facility beam stop. The ${\overline{\ensuremath{\nu}}}_{e}$ are detected via ${\overline{\ensuremath{\nu}}}_{e}p\ensuremath{\rightarrow}{e}^{+}n$ with ${e}^{+}$ energy between 36 and $60\mathrm{MeV}$, followed by a $\ensuremath{\gamma}$ ray from $\mathrm{np}\ensuremath{\rightarrow}d\ensuremath{\gamma}$ ( $2.2\mathrm{MeV}$). Using strict cuts to identify $\ensuremath{\gamma}$ rays correlated with ${e}^{+}$ yields 9 events with only $2.1\ifmmode\pm\else\textpm\fi{}0.3$ background expected. A likelihood fit to the entire ${e}^{+}$ sample results in a total excess of ${16.4}_{\ensuremath{-}8.9}^{+9.7}\ifmmode\pm\else\textpm\fi{}3.3$ events. If attributed to ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\overline{\ensuremath{\nu}}}_{e}$ oscillations, this corresponds to an oscillation probability of ( ${0.34}_{\ensuremath{-}0.18}^{+0.20}\ifmmode\pm\else\textpm\fi{}0.07$)%.

Dilute scintillation mixtures emit isotropic light for both fast and slow particles, but retain the Cherenkov light cone from fast particles. Large volume detectors using photomultipliers to reconstruct relativistic tracks will also be sensitive to slow particles if they are filled with these mixtures. Our data show that 0.03 g/l of b-PBD in mineral oil has a 2.4:1 ratio (in the first 12 ns) of isotropic light to Cherenkov light for positron tracks. The light attenuation length is greater than 15 m for wavelength above 400 nm, and the scintillation decay time is about 2 ns for the fast component. There is also a slow isotropic light component that is larger (relative to the fast component) for protons than for electrons. This effect allows particle identification by a technique similar to pulse shape discrimination. These features will be utilized in LSND, a neutrino detector at LAMPF.

No evidence for the neutrinoless double-\ensuremath{\beta} decay of $^{100}\mathrm{Mo}$ has been found in a search using a segmented Si(Li) detector with source foils enriched to 97% $^{100}\mathrm{Mo}$. After 0.2664 mole years of exposure, we report a 1\ensuremath{\sigma} lower limit on the half-life for the ${\mathit{J}}^{\mathit{P}}$=${0}^{+}$\ensuremath{\rightarrow}${0}^{+}$ transition of 0.44\ifmmode\times\else\texttimes\fi{}${10}^{23}$ years.

When static electric fields (F\ensuremath{\le}90 kV/cm) were applied to the ${\mathrm{H}}^{\mathrm{\ensuremath{-}}}$ photodetachment interaction region, new structure and lowered thresholds for production of neutral hydrogen were observed. Relative partial cross sections were measured by detection of excited states of the fragment neutral hydrogen atom H(N=4, 5, or 6) resulting from laser interaction with relativistic ${\mathrm{H}}^{\mathrm{\ensuremath{-}}}$ ions. Downward shifts in the onset of excited hydrogen production are observed to increase with field strength, and agree with a recent hyperspherical coordinate interpretation of Zhou and Lin [Phys. Rev. Lett. 69, 3294 (1992)]. Field-induced window-type resonance structure is observed both below and above the zero-field threshold (ZFT) energy. Quenching of high-lying autoionizing states was also monitored, providing evidence of field-induced tunneling by resonances lying just below the associated ZFT.

Conditions under which some plants emit carbon disulfide (CS2) in the soil are unknown. A pot assembly was constructed to measure soil CS2 emissions by Mimosa pudica under conditions of undisturbed growth, root injury, and drought stress. When M. pudica was grown without disturbance, soil CS2 emissions were below the limit of detection (≤0.1 ng CS2 mL−1) for the entire 8-wk sampling period. However, when the roots of 6-wk-old M. pudica plants were cut to a depth of 10 cm, a maximum of 0.5 and 0.4 ng CS2 mL−1 was emitted within minutes at the 5- and 10-cm depths, respectively. These emissions declined slowly to undetectable levels after 50 min. No detectable CS2 emissions were observed at the 0- and 15-cm depths. No CS2 was emitted when 6-wk-old M. pudica plants were subjected to drought stress, however, when the same plants were watered, a maximum of 0.3, 0.4, and 0.5 ng CS2 mL−1 was emitted within minutes at the 5-, 10- and 15-cm depths, respectively. These emissions were detectable for at least 2 hr at the 10- and 15-cm depths. No detectable CS2 emissions were observed at the 0-cm depth after watering. No detectable CS2 emissions were observed at any depth under any conditions of undisturbed growth, root injury, or drought stress followed by watering for assemblies containing either no plants or Albizia julibrissin, a plant that is closely related to M. pudica but does not emit CS2. Mimosa pudica emitted detectable CS2 under conditions of root injury and rewetting of dry soil but not under conditions of undisturbed growth. Release of such a biocidal sulfide only during conditions of root injury or rewetting of dry soil would be advantageous to M. pudica.

Deep tillage is often prescribed to alleviate subsoil compaction, but how long do the benefits last? Subsoilers from Deere, DMI, Kewanee, Tye, and Yetter were operated at a 280-mm depth on a compacted 25-ha field in autumn 1990. The different subsoiler designs were evaluated by draft, crop residue cover, soil physical properties and yield measurements over the subsequent two growing seasons. Air porosity and cone penetrometer measurements showed continuing benefits, from all subsoil operations, two years after tillage in areas not trafficked. However, two passes of a tractor recompacted the soil. Controlled traffic is, therefore, considered essential to obtain long-term benefits from subsoiling. Compared to check strips, soybean yield increases for the five subsoilers ranged from 3.0 to 6.9% in 1991 and corn yield increases ranged from 1.5 to 3.0% in 1992. Economically, the first year yields paid for the subsoiling, second year increases were profit.

Changes in soil physical properties resulting from multiple passes of an 18 m3 single-axle grain cart with a 15.2 t axle load were measured one year after the traffic occurred. Air permeability, air-filled porosity, and dry density data were analyzed to determine how the soil responded to grain cart traffic and pre- and post-traffic tillage. Four repeated passes of the cart decreased air-filled porosity and permeability by as much as 50% in the 200- to 400-mm depth range when compared to the effect of a single wheel pass. With pre-traffic chisel plowing to a depth of 200 mm, most of the compaction in the 100- to 200-mm depth occurred on the first pass. However, four repeated passes had a greater effect on soil properties in the plots that received no tillage compared to the plots that were chiseled before trafficking.

Stable trains of 100–200-ns-long pulses are obtained at 0.46–1.06-MHz repetition rates in a Nd:glass fiber laser by driving large-amplitude relaxation oscillations at or below their resonance. Numerical simulations agree qualitatively with temporal profiles of the output power. We show that the maximum pulse-repetition rate of a relaxation-oscillation laser increases as the square root of pump power at low P and that its theoretical upper limit is close to the pulse rate of a mode-locked laser.

The compound Bi1/2Ag1/2TiO3 has been synthesized, for the first time, at 14−14.5 GPa and 1000 °C using the uniaxial split sphere anvil type press (USSA-2000). The structure of the quenched powder s...

Multiphoton detachment from H{sup {minus}} has been studied using linearly polarized light for photon energies from 0.15 to 0.39 eV. Characteristic threshold structures were observed. The electron detachment rates are estimated at peak laser intensities from 2 to 12 GW/cm{sup 2} in the laboratory frame. The two-photon detachment data reveal intensity-dependent shifts of the H{sup {minus}} electron detachment threshold energy.

We report the optical transmission properties of holographic band-reject filters designed for Raman spectroscopy using excitation at 514.5 nm and at 632.8 nm. We use these data to quantitatively evaluate the compromise between rejection of elastic scatter and transmission of Raman bands as a function of Raman shift. We demonstrate the use of a single filter for the rejection of elastically scattered light from the Raman spectra of a white powder and of a clear liquid.

Detachment of electrons from the H − ion is investigated with an experimental technique whereby an H − beam moving at a relativistic velocity (2.5 × 10 10 cm/s) is intersected with a fixed frequency laser. The Doppler effect allows systematic variation of the center-of-mass (CM) photon energy over a wide range (factor of 10) by simply adjusting the angle between the ion and laser beams. The focused output from a pulsed, linearly polarized, CO 2 TEA laser operating at 10.6 μm, with peak intensities on the order of 10 GW/cm 2 , was used to examine the multiphoton absorption process in H −2 . The fourth harmonic (266 nm) of a Nd:YAG laser was used to investigate some of the doubly-excited state resonances in H − . In the multiphoton absorption work, electron detachment was observed at photon energies where as few as 2 and as many as 8 photons are required to get above the 1-electron detachment threshold (EDT) of H − (0.754 eV). Electron yield vs photon energy plots exhibit structure that is laser intensity dependent. Electron yield vs laser pulse energy data was obtained at a few selected CM wavelengths and laser pulse energies. In the single-photon UV laser work, numerous resonances within the H − photodetachment continuum corresponding to one-photon two-electron excitation processes were observed. The doubly-excited resonances appear to be of the Feshbach type. A simple, semi-empirical recursion formula predicts the resonance energy levels. The experimental techniques described here can be used to accurately determine accelerator beam and ion source parameters such as beam energy, energy-spread, and ion density spatial distribution.

The response of relativistic H{sup {minus}} ions to thin carbon foils was investigated for beam energies ranging from 226 MeV to 800 MeV. For the foil thicknesses we have studied, ranging from 15 to 300 {mu}g/cm{sup 2}, an appreciable fraction of the H{sup {minus}} beam survives intact, some H{sup {minus}} ions are stripped down to protons, and the remainder is distributed over the states of H{sup 0}. This experiment is different from the low energy studies in that the projectile velocity is comparable to the speed of light, leading to an interaction time of typically less than a femtosecond. The present results challenge the theoretical understanding of the interaction mechanisms. An electron spectrometer was used to selectively field-ionize the Rydberg states, 9 < n < 17, at beam energies of 581 MeV and 800 MeV. The yield of low-lying states were measured by Doppler tuning a Nd:YAG laser to excite transitions to a Rydberg state which was then field-ionized and detected. A simple model is developed to fit the yield of each state as a function of foil thickness. The simple model is successful in predicting the general features of the yield data. However, the data are suggestive of amore » more complex structure in the yield curves. The yield of a given state depends strongly on the foil thickness, demonstrating that the excited states are formed during the passage of the ions through a foil. The optimum thickness to produce a given state increases with the principal quantum number of the state suggesting an excitation process which is at least pratially stepwise. The results of a Monte Carlo simulation are compared with the experimental data to estimate the distribution of the excited states coming out of a foil. The distributions of the excited states and their dependence on foil thickness are discussed.« less

The electrical conductivity, Seebeck coefficient, and power factor of $n$- and $p$-type PbTe were calculated over the temperature range of 300--700 K and carrier concentration range of $1\ifmmode\times\else\texttimes\fi{}{10}^{17}\ensuremath{-}4\ifmmode\times\else\texttimes\fi{}{10}^{19}\text{ }{\text{cm}}^{\ensuremath{-}3}$ by using the Boltzmann transport equation and relaxation time approximation and were compared to measurement results. A three-band model for PbTe was used and included scattering from screened polar optical phonons as well as the deformation potential of acoustic and optical phonons. Nonparabolicity and anisotropy of the principal conduction and valence bands at the $L$ point in the Brillouin zone were taken into account, and the calculated transport properties were in excellent agreement with measurement results over the full range of carrier concentrations and temperatures. The Lorenz number was also calculated and seen to vary from 0.54 to 0.89 of ${L}_{0}$ $(2.44\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}\text{ }\text{W}\text{ }\ensuremath{\Omega}\text{ }{\text{K}}^{\ensuremath{-}2})$ depending on the carrier concentration and temperature. The measured in-plane transport properties of epitaxially grown $n$- and $p$-type PbTe/PbSe nanodot superlattice (NDSL) samples with $\ensuremath{\sim}13%$ PbSe by volume fraction are also presented and discussed in comparison to the baseline homogeneous PbTe. The presence of the PbSe nanodots in a PbTe matrix was observed to reduce the carrier mobility by $\ensuremath{\sim}25%--35%$ while having no effect on the Seebeck coefficient, thus resulting in a reduced power factor for PbTe/PbSe NDSLs compared to PbTe. The properties of the NDSL samples were also observed to have the same temperature dependence as PbTe.

The use of laser spectroscopy for the determination of momentum spread and energy of a relativistic H− beam is discussed, and the results are presented of a successful attempt to reduce the momentum spread δpp by a factor of 5 from its initial value of approximately 5 × 10−4.

The results are presented of further studies of the effects of electric fields on the photodetachment cross section of ${\mathrm{H}}^{\mathrm{\ensuremath{-}}}$, for both \ensuremath{\pi} and \ensuremath{\sigma} polarization. Data are fitted to the theory of Rau and Wong [Phys. Rev. A 37, 632 (1988)], which predicts a modulation about the zero-field cross section. Agreement is good for \ensuremath{\pi} polarization, but the predicted profile for \ensuremath{\sigma} polarization does not appear to match the data quite as well.

Two sites, T2 and T3, in the ribosomal gene spacer of Xenopus laevis both direct RNA 3'-end formation 15 bp upstream of the conserved box sequence GACTTGC. Site T2, which defines the 3' end of the 40S precursor, does not terminate transcription whereas site T3 at the 3' end of the spacer does. Here we show that T2 can be converted into a T3-like site with termination activity by a single point mutation 2 bp downstream of the T2 box. RNA 3'-end formation at T2 is unchanged by this mutation. Conversely, a point mutation 2 bp downstream of the T3 box inhibits termination without affecting 3'-end formation. Our results identify two separable events occurring at the 3' end of the ribosomal genes: (1) RNA 3'-end formation by processing and (2) transcription termination. The two processes are directed by two distinct, but overlapping, signals in the DNA sequence. Site T2 in X. laevis is damaged in the second process by a natural mutation.

Ultra-low quantum defect operation Er lasers are discussed. Power scaling demonstration has shown promise for high efficiency Er:crystal laser operation.

1534 nm Fiber laser pumped Er:YAG laser action at room temperature has been demonstrated with high efficiency. CW power as high as 12 Watts was achieved at 1645 nm from Er:YAG where a single TEC controller was used for thermal management. Active EO Q-switched operation with kHz repetition rate and 27 ns pulse widths was achieved with the same laser resonator.

Fiber laser pumped Er:YAG laser action at 1617 nm was achieved at room temperature. An etalon was utilized for tuning the laser to the 1617 nm line. Room temperature operation was characterized and compared with 1645 nm operation. Output power close to 3 Watts CW was demonstrated at the 1617 nm laser line.

High-resolution surface fluxes over the global ocean are needed to evaluate coupled atmosphere–ocean models and weather forecasting models, provide surface forcing for ocean models, understand the regional and temporal variations of the exchange of heat between the atmosphere and ocean, and provide a large-scale context for field experiments. Under the auspices of the World Climate Research Programme (WCRP) Global Energy and Water Cycle Experiment (GEWEX) Radiation Panel, the SEAFLUX Project has been initiated to investigate producing a high-resolution satellite-based dataset of surface turbulent fluxes over the global oceans to complement the existing products for surface radiation fluxes and precipitation. The SEAFLUX Project includes the following elements: a library of in situ data, with collocated satellite data to be used in the evaluation and improvement of global flux products; organized intercom-parison projects, to evaluate and improve bulk flux models and determination from the satellite of the input parameters; and coordinated evaluation of the flux products in the context of applications, such as forcing ocean models and evaluation of coupled atmosphere–ocean models. The objective of this paper is to present an overview of the status of global ocean surface flux products, the methodology being used by SEAFLUX, and the prospects for improvement of satellite-derived flux products.

5-fluorouracil (5-FU) targets rapidly dividing cancer cell populations. In turn, it may cause inflammation in such rapidly dividing tissues as the corneal epithelium, conjunctiva, and tear duct. Inflammation may be exacerbated by pre-existing dermatologic conditions. This case report describes a rare combination of facial dermatologic toxicity and ectropion.A 76-year-old man came to us in October 1998 with symptoms of foreign body sensation, epiphora, and difficulty removing his contact lenses. His medical history was significant for 5-FU bolus injections for intestinal cancer since May 1998. Examination revealed facial erythema and eczema, ectropion, blepharitis, chemosis, lid teleangectasia, and contact lens-related corneal edema. Differential diagnoses included ocular rosacea with cicatrizing conjunctivitis and 5-FU-induced ectropion. He was treated and monitored over the subsequent several months. As of December 1998, only mild ectropion persisted.Patients with 5-FU-induced ectropion experience tender, red, scaled lids, making contact lens wear difficult. Therefore, contact lens wear should be discontinued to prevent further complications. This patient's ectropion and facial eczema may have been confounded by ocular rosacea. Exacerbation of 5-FU dermatologic toxicities in patients with preexisting conditions suggests the importance of aggressive ocular prophylaxis, using frequent ocular lubrication and topical steroid preparations with concurrent medical management of pre-existing dermatologic conditions.This case illustrates a potential link between dermatologic and ocular 5-FU toxicities. Further research and better communication among health care professionals are needed to determine if prophylaxis can reduce adverse ocular events.

The mechanism by which cells in the ampullae of the rat oviducts undergo rapid deciliation during each estrous cycle and the effects of estrogen on the ciliated cells were examined. Untreated rats were killed on each day of the 5-day estrous cycle, and the ampullae of their oviducts were removed. Other rats were injected subcutaneously each day for 5 days with 0.3 microgram or 3.0 micrograms of estradiol benzoate or with 0.3 mg of tamoxifen, an estrogen antagonist, per kilogram of body weight. The ampullae of the oviducts of the treated rats were excised on the day following the last injection. The tissues from all the rats were fixed in glutaraldehyde, stained with uranyl acetate and lead citrate, and examined with a transmission electron microscope. Deciliation of cells was seen to occur by membrane-bound cilia packets (CPs) forming at the apices of cells and pinching off. Although CPs were more numerous at proestrus, they were also observed at estrus, diestrus-1, and diestrus-2, suggesting that the process of deciliation is an ongoing one that merely changes in rate. No evidence of resorption of cilia was seen. Estradiol treatment did not prevent CPs from forming, nor was tamoxifen treatment associated with any apparent enhancement of deciliation. Ciliated cells with CPs stained more darkly than ciliated cells that were without CPs, and the former appeared similar in their staining characteristics to secretory cells, most of which stain darkly. It was concluded that the cells of the ampulla deciliate rapidly by shedding their cilia into the lumen of the oviduct, that estrogen does not halt the process, and that ciliated cells may be transformed to secretory cells following loss of their cilia.

This article focuses on what is currently known about the regulation of transcription by RNA polymerase I (pol I) in eukaryotic organisms at opposite ends of the evolutionary spectrum--a yeast, Saccharomyces cerevisiae, and vertebrates, including mice, frogs, and man. Contemporary studies that have defined the DNA sequence elements are described, as well as the majority of the basal transcription factors essential for pol I transcription. Situations in which pol I transcription is known to be regulated are reviewed and possible regulatory mechanisms are critically discussed. Some aspects of basal pol I transcription machinery appear to have been conserved from fungi to vertebrates, but other aspects have evolved, perhaps to meet the needs of a metazoan organism. Different parts of the pol I transcription machinery are regulatory targets depending on different physiological stimuli. This suggests that multiple signaling pathways may also be involved. The involvement of ribosomal genes and their transcripts in events such as mitosis, cancer, and aging is discussed.

A 64 x 64 mercury-cadmium-telluride focal-plane array detector attached to a Fourier transform infrared microscope was used to spectroscopically image 5 microm sections of canine alveolar bone tissue in the fingerprint region of the infrared spectrum. By ratioing the relative intensities of specific bands across the images, it is possible to obtain spatial distributions of the mineral-to-matrix ratio and mineral maturity as a function of distance from an osteon.

A 64×64 Mercury-Cadmium-Telluride (MCT) focal-plane array (FPA) detector coupled to a step-scanning Fourier transform infrared (FT-IR) microscope has been used to acquire spectroscopic images in the fingerprint region of the infrared spectrum (1800–900 cm−1). FT-IR microspectroscopic imaging using this MCT FPA enabled us to chemically identify a 7.5-μm-thick adhesive tie layer in a polymer laminate packaging material. Infrared spectroscopic images of cross sections of human bone tissue obtained using the MCT FPA detector are also presented. The protein, carbonate, and phosphate concentrations change as a function of radial distance from an osteon.

Rats with regular 5-day estrous cycles were sacrificed on different days of the cycle and the ampullae of their oviducts were excised, fixed in glutaraldehyde, stained with uranyl acetate and lead citrate, and examined using electron microscopy. Since the ampullae undergo changes in their gross morphology during each estrous cycle, an attempt was made to correlate those changes in morphology with cyclic changes in ultrastructure of the cells and with cyclic physiological events. During the course of the estrous cycle, there were changes in the relative numbers of secretory and ciliated cells in the ampullae; secretory cells increased in numbers at estrus, became the dominant cell type at metestrus, and became rare at diestrus-1, a day on which ciliated cells prevailed. On the remaining days of the cycle both cell types were evident with more secretory cells seen at diestrus-2 and more ciliated cells seen at proestrus. The secretory cells exhibited two phases of secretion, one in which vesicles were seen to bleb from their surfaces at estrus and another in which dense granules accumulated at the apices of the cells at metestrus, only to disappear by the following day. Evidence of fluid resorption between the days of estrus and metestrus was seen. The days in which the secretory cells of the ampullae exhibited morphological changes indicative of increased activity, the days of estrus and metestrus, were the days in which oocytes can be found in that portion of the oviducts.

A search for neutrino oscillations of the type nu_bar_mu to nu_bar_e has been conducted at the Los Alamos Meson Physics Facility using nu_bar_mu from muon decay at rest. Evidence for this transition has been reported previously. This paper discusses in detail the experimental setup, detector operation and neutrino source, including aspects relevant to oscillation searches in the muon decay-at-rest and pion decay in flight channels., 27 pages, 26 figures, revtex and psfig, additional information available at http://nu1.lampf.lanl.gov/~lsnd/

A small percentage of children who have received the Nucleus multichannel cochlear implant have cochlear malformations of the inner ear and consequent partial electrode insertions. This case describes one child with a cochlear "common cavity" who received an implant at a young age. The case has been further complicated by a gradual malfunction of the electrode array, although the device has not failed completely. Despite the increase in the number of nonfunctional electrodes over time, the subject has continued to improve in auditory, speech production, and language development over a 30-month period. Methods are discussed for clinical monitoring of both performance and the stability of electrodes over time. The circumstances of this case reinforce the importance of postimplant collaboration with families and school staff and highlight the need for objective measures to evaluate both longitudinal changes in performance and device integrity.

Inclusive double differential neutron induced ${\mathrm{\ensuremath{\pi}}}^{+}$ and ${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$ production cross sections were measured as a function of neutron energy for four targets: C, Al, Cu, and W. The neutron energy range was 200\char21{}600 MeV and the pion angular range was 25\ifmmode^\circ\else\textdegree\fi{}\char21{}125\ifmmode^\circ\else\textdegree\fi{} (laboratory). The charge, scattering angle, and energy of the pions were measured. The measurements are compared with intranuclear cascade (INC) calculations and a previous experiment that measured the sum of the ${\mathrm{\ensuremath{\pi}}}^{+}$ and ${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$ cross sections. Our data agree with the measured data, but the INC calculations give only moderate agreement both with the double differential cross sections as well as with angular distributions and total cross sections as a function of neutron energy. The ratio ${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$:${\mathrm{\ensuremath{\pi}}}^{+}$ was found to increase rapidly with decreasing neutron energy and the pion production was found to increase approximately as ${\mathit{A}}^{2/3}$ for the different targets.

Laser photodetachment on a relativistic H{sup {minus}} beam has revealed several series of resonances in which both electrons are excited. These bound states in the continuum'' appear as dips in the partial production cross sections of various excited states of neutral hydrogen. We present here a detailed account of the experimental observation of the resonances and the results of fits of the measured yields to sets of Fano profiles. A simple analytic formula for the energy-level spacing in this quantum-mechanical three-body system is verified.

Several series of doubly excited resonances have been observed in ${\mathrm{H}}^{\mathrm{\ensuremath{-}}}$ photodetachment, appearing as dips in the production cross section of excited neutral hydrogen. At least three resonances are clearly visible converging on each of the thresholds n=5, 6, 7, and 8. The data support recent theoretical calculations for the energies of doubly excited resonances and verify a Rydberg-dipole formula for the main resonance positions.

Studies of the production of H° its various states by the passage of relativistic H− ions through thin foils are under way at the linear accelerator at Los Alamos. Laser excitation and selective field ionization are used to isolate specific states. We present evidence that the excitation of Rydberg states by a foil at energies up to 800 meV proceeds in a stepwise manner.

Blueberry plants fertilized at 3-week intervals with nitrogen (N) throughout the year and protected from freezing temperatures avoid dormancy and produce an off-season “winter” crop. Southwestern Florida offers a climate where this production system can be implemented without undue fear of freezes. `Sharpblue', `Gulfcoast', and `Warmabe' southern highbush blueberry cultivars have been planted at high density (10,000 plants/ha) to determine the feasibility of successfully establishing an evergreen production system for blueberry. Three rates of N fertilization (84, 168, and 252 kg·ha–1) and the use of peat or municipal solid waste (MSW) compost as soil amendments are being evaluated in this study. Initial data on plant growth indicate that, during the first 9 months of the planting, 168 kg N/ha will produce plants similar in height, but with significantly less volume, to those receiving 252 kg N/ha. MSW compost appears to be a beneficial soil amendment for blueberry establishment despite an increase in soil pH associated with the compost amendment.