SMAPVEX12: the latest dirt on soil moisture monitoring with remote sensing

Non-Peer Reviewe

Chickpea in semiarid cropping systems

Non-Peer ReviewedRelative to other pulse crops such as dry-pea (Pisum sativum L.) and lentil (Lens culinaris L.), chickpea (Cicer arietinum L.) is still new in western Canada. In 1999, there were 350,000 acres of chickpea seeded in Saskatchewan with more than 75% of the seeded area being located in the districts of Swift Current, Shaunavon, Moose Jaw, Rosetown, and Assiniboia (Noble 2000). Approximately 93% of the seeded chickpea area was harvested in Saskatchewan in 1999 (Statistics Canada, 1999). Due to abundant rainfall and generally cooler than normal growing conditions in 1999, some late-seeded chickpea fields did not reach full maturity. The best production success came in the southwest corner of Saskatchewan where the growing season (May to August) precipitation usually is less than 8 inches. The deeper rooting habit and the tolerance to water stress makes chickpea a winner under these adverse drought conditions. The objective of this study was to develop agronomic information for the inclusion of chickpea in cropping systems for the semiarid prairie region. The focus has been on aspects pertaining chickpea water use characteristics, stubble effect, re-cropping constraints, and other rotational considerations

Optimum plant population density for chickpea in a semiarid environment

Non-Peer ReviewedChickpea (Cicer arietinum L.), an annual grain legume, is being rapidly included in cereal-based cropping systems throughout the semiarid Canadian prairies, but information on optimum plant population density (PPD) has not been developed for this region. This study was conducted from 1998 to 2000 in southwestern Saskatchewan to determine the impact of PPD on field emergence, seed yield and quality, and harvestability of kabuli and desi chickpea compared with dry pea (Pisum sativum L.). Seed yields of all legumes increased with increasing PPD when the crops were grown on conventional summerfallow. The PPD that produced the highest seed yields ranged from 40 to 45 plants m-2 for kabuli chickpea, 45 to 50 plants m-2 for desi chickpea, and 75 to 80 plants m-2 for dry pea. When the legumes were grown on wheat stubble, the PPD that gain optimum seed yield ranged from 35 to 40 plants m-2 for kabuli, 40 to 45 plants m-2 for desi chickpea, and 65 to 70 plants m-2 for dry pea. The proportion of large-sized (>9-mm diameter) seed in the harvested seed was >70% when the kabuli chickpea was grown on summerfallow regardless of PPD, whereas the large-seed proportion decreased with increasing PPD when the crop was grown on wheat stubble. Increases in PPD advanced plant maturity by 1.5 to 3.0 days, and also increased the height of lowest pods from the soil surface by 1.4 to 2.0 cm (or 5 to 10%), with desi type receiving the greatest benefits from increased PPD

The 13-C(p,d) Reaction at 120 MeV

This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

Water use and water use efficiency of field pea and chickpea under the semiarid Canadian prairie conditions

Non-Peer Reviewe

Strong Cosmic Censorship and Causality Violation

We investigate the instability of the Cauchy horizon caused by causality violation in the compact vacuum universe with the topology $B\times {\bf S}^{1}\times {\bf R}$, which Moncrief and Isenberg considered. We show that if the occurrence of curvature singularities are restricted to the boundary of causality violating region, the whole segments of the boundary become curvature singularities. This implies that the strong cosmic censorship holds in the spatially compact vacuum space-time in the case of the causality violation. This also suggests that causality violation cannot occur for a compact universe.Comment: corrected version, 8 pages, one eps figure is include

The role of dynamical polarization of the ligand to metal charge transfer excitations in {\em ab initio} determination of effective exchange parameters

The role of the bridging ligand on the effective Heisenberg coupling parameters is analyzed in detail. This analysis strongly suggests that the ligand-to-metal charge transfer excitations are responsible for a large part of the final value of the magnetic coupling constant. This permits to suggest a new variant of the Difference Dedicated Configuration Interaction (DDCI) method, presently one of the most accurate and reliable for the evaluation of magnetic effective interactions. This new method treats the bridging ligand orbitals mediating the interaction at the same level than the magnetic orbitals and preserves the high quality of the DDCI results while being much less computationally demanding. The numerical accuracy of the new approach is illustrated on various systems with one or two magnetic electrons per magnetic center. The fact that accurate results can be obtained using a rather reduced configuration interaction space opens the possibility to study more complex systems with many magnetic centers and/or many electrons per center.Comment: 7 pages, 4 figure

Response of cereals to fertilizer N on pulse and other stubbles

Non-Peer ReviewedTo optimize cropping systems requires knowledge of effects of the preceding crop on the grain yield and protein and the response to N of a following cereal crop. To gain this knowledge, we grew hard red spring (HRS) wheat, durum wheat, Canadian Prairie Spring (CPS)-class wheat, Canadian Western Extra Strong (CWES)-class wheat, and barley on barley, bean, coriander, fenugreek, kabuli chickpea, lentil, mustard, and pea stubble at different N fertilizer rates over 9 site-yr: Swift Current (1998-2002), Redvers (2001-02), and Canora (1999 and 2002). N rates were medium (recommended rate based on fall soil nitrate in cereal stubble), low (15-30 kg ha-1 less than medium) and high (15-30 kg ha-1). There was a significant effect of stubble on subsequent cereal grain yield. Cereal on cereal stubble was consistently lowest or second lowest yielding (typically 100 – 800 kg ha-1 lower than other stubbles) with the exception of 2001 at Swift Current when it was the highest yielding. This latter effect was attributed to the superior moisture conserving benefits of cereal stubble during this year with extreme early drought. No single cereal crop was consistently highest or lowest yielding. The trend was for greatest grain protein on pulse stubbles although stubble effects on protein were not as great as on yield owing to confounding yield dilution effects. Within this narrow range of fertilizer N rates, yield or protein response to N was weak. Generally, there were no significant interactions between stubble and cereal crop or stubble and fertilizer indicating the effect of stubble was consistent across cereal type and N rates. The cereal yield and protein response to N on the non-cereal stubbles was not significantly different than that on cereal stubble with the exception that barley protein responded more positively to N on lentil stubble than on cereal stubble. Cereals grown on pulse stubbles tended to have higher yields and protein than on other stubbles. For HRS wheat and durum, the chance of achieving high protein grain was greatest with high fertilizer N on pea stubble (>75% of years). Applying a high fertilizer N rate on cereal stubbles did not markedly increase the chance of attaining high protein wheat or durum. For barley, where low protein is desired for malting, the best chance for low protein barley was on cereal and mustard stubble although barley protein appeared less affected by stubble and fertilizer N than wheat or durum

Chemical Changes of Flattened Enamel Surfaces with in Vitro Weak Acid Demineralization

Infrared internal reflection spectroscopy (IRS) was used to study changes in surface chemistry of enamel after in vitro weak acid demineralization. Hypotheses that relate previous histomorphologic observations to current IRS findings are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68276/2/10.1177_00220345710500064001.pd

Decoherence from a Chaotic Environment: An Upside Down "Oscillator" as a Model

Chaotic evolutions exhibit exponential sensitivity to initial conditions. This suggests that even very small perturbations resulting from weak coupling of a quantum chaotic environment to the position of a system whose state is a non-local superposition will lead to rapid decoherence. However, it is also known that quantum counterparts of classically chaotic systems lose exponential sensitivity to initial conditions, so this expectation of enhanced decoherence is by no means obvious. We analyze decoherence due to a "toy" quantum environment that is analytically solvable, yet displays the crucial phenomenon of exponential sensitivity to perturbations. We show that such an environment, with a single degree of freedom, can be far more effective at destroying quantum coherence than a heat bath with infinitely many degrees of freedom. This also means that the standard "quantum Brownian motion" model for a decohering environment may not be as universally applicable as it once was conjectured to be.Comment: RevTeX, 29 pages, 5 EPS figures. Substantially rewritten analysis, improved figures, additional references, and errors fixed. Final version (to appear in PRA