Improving predictive power of physically based rainfall-induced shallow landslide models: a probabilistic approach

Distributed models to forecast the spatial and temporal occurrence of rainfall-induced shallow landslides are based on deterministic laws. These models extend spatially the static stability models adopted in geotechnical engineering, and adopt an infinite-slope geometry to balance the resisting and the driving forces acting on the sliding mass. An infiltration model is used to determine how rainfall changes pore-water conditions, modulating the local stability/instability conditions. A problem with the operation of the existing models lays in the difficulty in obtaining accurate values for the several variables that describe the material properties of the slopes. The problem is particularly severe when the models are applied over large areas, for which sufficient information on the geotechnical and hydrological conditions of the slopes is not generally available. To help solve the problem, we propose a probabilistic Monte Carlo approach to the distributed modeling of rainfall-induced shallow landslides. For the purpose, we have modified the Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Analysis (TRIGRS) code. The new code (TRIGRS-P) adopts a probabilistic approach to compute, on a cell-by-cell basis, transient pore-pressure changes and related changes in the factor of safety due to rainfall infiltration. Infiltration is modeled using analytical solutions of partial differential equations describing one-dimensional vertical flow in isotropic, homogeneous materials. Both saturated and unsaturated soil conditions can be considered. TRIGRS-P copes with the natural variability inherent to the mechanical and hydrological properties of the slope materials by allowing values of the TRIGRS model input parameters to be sampled randomly from a given probability distribution. [..]Comment: 25 pages, 14 figures, 9 tables. Revised version; accepted for publication in Geoscientific Model Development on 13 February 201

Development of fuel cell electrodes, Electrode improvement and life testing, tasks 1 and 3 Final report, 30 Jun. 1966 - 30 Apr. 1968

Volt-ampere characteristics improvement and life testing of electrodes for hydrogen oxygen fuel cell

HST/STIS Spectroscopy of the Lyman-Alpha Emission Line in the Central Dominant Galaxies in A426, A1795, and A2597: Constraints on Clouds in the Intracluster Medium

We report on HST/STIS spectra of the Lyman-alpha emission in the central dominant galaxies in three rich clusters of galaxies. We find evidence for a population of clouds in the intracluster medium.We detect 10 Ly-alpha absorption systems towards the nucleus of NGC1275 with columns of N(HI) 1E12-1E14 cm-2. The detected absorption features are most consistent with associated nuclear absorption systems. There is very little nuclear absorption at the systemic velocity in NGC1275. This implies that the large columns detected in the 21 cm line towards the parsec scale radio source avoid the line of sight to the nucleus. This gas may be located in a circumnuclear disk or torus. We detect at least one and possibly two absorption features towards the extended Ly-alpha in A426. We do not detect absorption towards the extended Ly-alpha emission in A1795, and A2597 with upper limits N(HI) 1E13 cm-2 for optically thin absorbers. Our data constrain the covering factor of any high column density gas in the ICM to be less than 25%. Our results suggest that the lack of observed intermediate temperature gas is not explained by obscuration. In addition, the low columns of gas on the 100 kpc scales in the ICM suggests that (1) the rate at which cold gas accumulates in the ICM on these scales is very low, and (2) the dense nebulae in the central 10 kpc must have cooled or been deposited in situ.Comment: 6 figure

Recent advances and application of doubled haploids in wheat breeding

Genetic improvement to develop varieties with high yield potential and resistance/tolerance to abiotic and  biotic stresses with acceptable end use qualities is the most viable and environment friendly option to increase wheat yield in a sustainable fashion. In vitro haploid production followed by chromosome doubling greatly  enhances the production of complete homozygous wheat lines in a single generation and increases the  precision and efficiency of selection process in wheat breeding. It also enables the detection of linkage and  gene interactions, estimate genetic variance and the number of genes for quantitative characteristics, produce genetic translocations, substitutions and chromosome addition lines, and facilitate genetic transformation and mutation studies. Wheat cultivars developed from doubled haploids using anther-culture and maize induction systems have been released for cultivation in both developed and developing countries. In this review, the  origin and production of haploids, techniques in anther-culture and wheat x maize wide crosses, and their  application in wheat breeding are summarized.Key words: Doubled haploid, wheat breeding, wheat yield

WFPC2 LRF Imaging of Emission Line Nebulae in 3CR Radio Galaxies

We present HST/WFPC2 Linear Ramp Filter images of high surface brightness emission lines (either [OII], [OIII], or H-alpha+[NII]) in 80 3CR radio sources. We overlay the emission line images on high resolution VLA radio images (eight of which are new reductions of archival data) in order to examine the spatial relationship between the optical and radio emission. We confirm that the radio and optical emission line structures are consistent with weak alignment at low redshift (z < 0.6) except in the Compact Steep Spectrum (CSS) radio galaxies where both the radio source and the emission line nebulae are on galactic scales and strong alignment is seen at all redshifts. There are weak trends for the aligned emission line nebulae to be more luminous, and for the emission line nebula size to increase with redshift and/or radio power. The combination of these results suggests that there is a limited but real capacity for the radio source to influence the properties of the emission line nebulae at these low redshifts (z < 0.6). Our results are consistent with previous suggestions that both mechanical and radiant energy are responsible for generating alignment between the radio source and emission line gas.Comment: 80 pages, 54 figures. Accepted for publication in ApJ

Spin-filter effect of the europium chalcogenides: An exactly solved many-body model

A model Hamiltonian is introduced which considers the main features of the experimental spin filter situation as s-f interaction, planar geometry and the strong external electric field. The proposed many-body model can be solved analytically and exactly using Green functions. The spin polarization of the field-emitted electrons is expressed in terms of spin-flip probabilities, which on their part are put down to the exactly known dynamic quantities of the system. The calculated electron spin polarization shows remarkable dependencies on the electron velocity perpendicular to the emitting plane and the strength of s-f coupling. Experimentally observed polarization values of about 90% are well understood within the framework of the proposed model.Comment: accepted (Physical Review B); 10 pages, 11 figures; http://orion.physik.hu-berlin.de