Economic viability of phytoremediation of a cadmium contaminated agricultural area using energy maize: part I: effect on the farmer's income

This paper deals with the economic viability of using energy maize as a phytoremediation crop in a vast agricultural area moderately contaminated with metals. The acceptance of phytoremediation as a remediation technology is, besides the extraction rate, determined by its profitability, being the effects it has on the income of the farmer whose land is contaminated. This income can be supported by producing renewable energy through anaerobic digestion of energy maize, a crop that takes up only relatively low amounts of metals, but that can be valorised as a feedstock for energy production. The effect on the income per hectare of growing energy maize instead of fodder maize seems positive, given the most likely values of variables and while keeping the basic income stable, originating from dairy cattle farming activities. We propose growing energy maize aiming at risk-reduction, and generating an alternative income for farmers, yet in the long run also generating a gradual reduction of the pollution levels. In this way, remediation is demoted to a secondary objective with sustainable risk-based land use as primary objective

Event horizons and ergoregions in 3He

Event horizons for fermion quasiparticles naturally arise in moving textures in superconductors and Fermi superfluids. We discuss the example of a planar soliton moving in superfluid 3He-A, which is closely analogous to a charged rotating black hole. The moving soliton will radiate quasiparticles via the Hawking effect at a temperature of about 5 \mu K, and via vacuum polarization induced by the effective `electromagnetic field' and `ergoregion'. Superfluid 3He-A thus appears to be a useful system for experimental and theoretical simulations of quantum effects related to event horizons and ergoregions.Comment: RevTex, 8 pages, 3 figures, submitted to Phys. Rev. D, corrected after referee repor

Kilohertz QPO Frequency and Flux Decrease in AQL X-1 and Effect of Soft X-ray Spectral Components

We report on an RXTE/PCA observation of Aql X-1 during its outburst in March 1997 in which, immediately following a Type-I burst, the broad-band 2-10 keV flux decreased by about 10% and the kilohertz QPO frequency decreased from 813+-3 Hz to 776+-4 Hz. This change in kHz QPO frequency is much larger than expected from a simple extrapolation of a frequency-flux correlation established using data before the burst. Meanwhile a very low frequency noise (VLFN) component in the broad-band FFT power spectra with a fractional root-mean-square (rms) amplitude of 1.2% before the burst ceased to exist after the burst. All these changes were accompanied by a change in the energy spectral shape. If we characterize the energy spectra with a model composed of two blackbody (BB) components and a power law component, almost all the decrease in flux was in the two BB components. We attribute the two BB components to the contributions from a region very near the neutron star or even the neutron star itself and from the accretion disk, respectively.Comment: 12 pages with 4 figures, accepted for publication in ApJ Letters, typos corrected and references update

Phonon Rabi-assisted tunneling in diatomic molecules

We study electronic transport in diatomic molecules connected to metallic contacts in the regime where both electron-electron and electron-phonon interactions are important. We find that the competition between these interactions results in unique resonant conditions for interlevel transitions and polaron formation: the Coulomb repulsion requires additional energy when electrons attempt phonon-assisted interlevel jumps between fully or partially occupied levels. We apply the equations of motion approach to calculate the electronic Green's functions. The density of states and conductance through the system are shown to exhibit interesting Rabi-like splitting of Coulomb blockade peaks and strong temperature dependence under the it interacting resonant conditions.Comment: Updated version, 5 pages, 4 figures, to be published in Phys. Rev. B on 9/1

Optically-Induced Polarons in Bose-Einstein Condensates: Monitoring Composite Quasiparticle Decay

Nonresonant light-scattering off atomic Bose-Einstein condensates (BECs) is predicted to give rise to hitherto unexplored composite quasiparticles: unstable polarons, i.e., local ``impurities'' dressed by virtual phonons. Optical monitoring of their spontaneous decay can display either Zeno or anti-Zeno deviations from the Golden Rule, and thereby probe the temporal correlations of elementary excitations in BECs.Comment: 4 pages, 3 figure

Survival of a Diffusing Particle in a Transverse Shear Flow: A First-Passage Problem with Continuously Varying Persistence Exponent

We consider a particle diffusing in the y-direction, dy/dt=\eta(t), subject to a transverse shear flow in the x-direction, dx/dt=f(y), where x \ge 0 and x=0 is an absorbing boundary. We treat the class of models defined by f(y) = \pm v_{\pm}(\pm y)^\alpha where the upper (lower) sign refers to y>0 (y<0). We show that the particle survives with probability Q(t) \sim t^{-\theta} with \theta = 1/4, independent of \alpha, if v_{+}=v_{-}. If v_{+} \ne v_{-}, however, we show that \theta depends on both \alpha and the ratio v_{+}/v_{-}, and we determine this dependence.Comment: 4 page

Distinguishing Solar Flare Types by Differences in Reconnection Regions

Observations show that magnetic reconnection and its slow shocks occur in solar flares. The basic magnetic structures are similar for long duration event (LDE) flares and faster compact impulsive (CI) flares, but the former require less non-thermal electrons than the latter. Slow shocks can produce the required non-thermal electron spectrum for CI flares by Fermi acceleration if electrons are injected with large enough energies to resonate with scattering waves. The dissipation region may provide the injection electrons, so the overall number of non-thermal electrons reaching the footpoints would depend on the size of the dissipation region and its distance from the chromosphere. In this picture, the LDE flares have converging inflows toward a dissipation region that spans a smaller overall length fraction than for CI flares. Bright loop-top X-ray spots in some CI flares can be attributed to particle trapping at fast shocks in the downstream flow, the presence of which is determined by the angle of the inflow field and velocity to the slow shocks.Comment: 15 pages TeX and 2 .eps figures, accepted to Ap.J.Let

Remote sensing in Michigan for land resource management

The utilization of NASA earth resource survey technology as an important aid in the solution of current problems in resource management and environmental protection in Michigan is discussed. Remote sensing techniques to aid Michigan government agencies were used to achieve the following results: (1) provide data on Great Lakes beach recession rates to establish shoreline zoning ordinances; (2) supply technical justification for public acquisition of land to establish the St. John's Marshland Recreation Area; (3) establish economical and effective methods for performing a statewide wetlands survey; (4) accomplish a variety of regional resource management actions in the Upper Peninsula; and (5) demonstrate improved soil survey methods. The project disseminated information on remote sensing technology and provided advice and assistance to a number of users in Michigan

Information in Black Hole Radiation

If black hole formation and evaporation can be described by an $S$ matrix, information would be expected to come out in black hole radiation. An estimate shows that it may come out initially so slowly, or else be so spread out, that it would never show up in an analysis perturbative in $M_{Planck}/M$, or in 1/N for two-dimensional dilatonic black holes with a large number $N$ of minimally coupled scalar fields.Comment: 12 pages, 1 PostScript figure, LaTeX, Alberta-Thy-24-93 (In response to Phys. Rev. Lett. referees' comments, the connection between expansions in inverse mass and in 1/N are spelled out, and a figure is added. An argument against perturbatively predicting even late-time information is also provided, as well as various minor changes.

Effective spacetime and Hawking radiation from moving domain wall in thin film of 3He-A

An event horizon for "relativistic" fermionic quasiparticles can be constructed in a thin film of superfluid 3He-A. The quasiparticles see an effective "gravitational" field which is induced by a topological soliton of the order parameter. Within the soliton the "speed of light" crosses zero and changes sign. When the soliton moves, two planar event horizons (black hole and white hole) appear, with a curvature singularity between them. Aside from the singularity, the effective spacetime is incomplete at future and past boundaries, but the quasiparticles cannot escape there because the nonrelativistic corrections become important as the blueshift grows, yielding "superluminal" trajectories. The question of Hawking radiation from the moving soliton is discussed but not resolved.Comment: revtex file, 4 pages, 2 figures, submitted to JETP Let