Observation of Dislocations in Ice

Baker, Ian

doi:10.1021/jp963211s

Cited by 21 publications

(20 citation statements)

References 32 publications

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“…For instance, if ice from a cirrus anvil falls into a cloud with supercooled liquid (as depicted in the leftmost low cloud in Figure 1), then the liquid may be converted to ice through the Bergeron process (Baker 1997). Whether or not this occurs depends on whether the anvil ice falls into the lower cloud.…”

Section: Introductionmentioning

confidence: 99%

The role of vertically varying cloud fraction in the parametrization of microphysical processes in the ECMWF model

Jakob

Klein

1999

Quart J Royal Meteoro Soc

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SummaryGlobal Circulation Models (GCMs) have generally treated only the radiative impacts of vertically varying cloud fraction by use of a cloud overlap assumption. In this study, the microphysical impacts of vertically varying cloud fraction are addressed by developing a sub-grid scale precipitation model which resolves the vertical variation of cloud fraction. This sub-grid model subdivides the grid boxes into homogeneous columns which are either completely clear or cloudy. By comparing the columnaveraged microphysical quantities from the sub-grid scale precipitation model to the parametrization in the ECMWF model, the ability of the ECMWF model to account for the sub-grid nature of cloud and precipitation microphysics is assessed. It is found that the ECMWF model overestimates precipitation evaporation in the tropical mid-troposphere. This results from (a) an incorrect parametrization of the area of the grid box covered by precipitation, and (b) the inadequacy of assuming a single value for the precipitation rate in the grid box.In addition to assessing the ability of the ECMWF model to parametrize the sub-grid nature of cloud microphysics, the subgrid precipitation model is used to show that the cloud overlap assumption has a large impact on the evaporation of precipitation. In light of the current trend towards more sophisticated cloud and precipitation parametrization in GCMs, more attention should be paid to the impact of vertical cloud fraction variations on the parametrized microphysics.

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Section: Introductionmentioning

confidence: 99%

The role of vertically varying cloud fraction in the parametrization of microphysical processes in the ECMWF model

Jakob

Klein

1999

Quart J Royal Meteoro Soc

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“…The isolation of numerous plant disease resistance genes, of which each is effective against a single pathogenic microorganism, has revealed the existence of at least four distinct classes of race-specific R gene sequences (Baker et al, 1997;Hammond-Kosack and Jones, 1997). One question of immense practical significance to disease control is whether members from each R gene class will function when transferred between sexually incompatible plant species.…”

Section: Discussionmentioning

confidence: 99%

“…The isolation of several R genes involved in diverse plantpathogen interactions, conferring resistance to fungi, bacteria, viruses, and nematodes (Bent, 1996;Baker et al, 1997;Hammond-Kosack and Jones, 1997), has revealed four related but distinct classes of predicted R proteins that confer resistance conforming to Flor's gene-for-gene hypothesis. These R genes from tomato, tobacco, rice, flax, and Arabidopsis encode proteins that share one or more similar motifs: leucine-rich repeat (LRR) and Toll/interleukin/resistance (TIR) regions (implicated in protein-protein interactions), nucleotide binding sites (NBSs), and protein kinase domains (implicated in signaling).…”

Section: Introductionmentioning

confidence: 99%

“…By using mutational analysis, several additional loci required for disease resistance have been defined as required for full expression of R-Avr -mediated disease resistance (HammondKosack and Jones, 1996;Baker et al, 1997). One of these additional loci codes for a protein with motifs in common with R proteins; tomato Prf required for Pto function contains both NBS and LRR domains (Salmeron et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

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The Tomato Cf-9 Disease Resistance Gene Functions in Tobacco and Potato to Confer Responsiveness to the Fungal Avirulence Gene Product Avr9

et al. 1998

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The Cf-9 gene encodes an extracytoplasmic leucine-rich repeat protein that confers resistance in tomato to races of the fungus Cladosporium fulvum that express the corresponding avirulence gene Avr9. We investigated whether the genomic Cf-9 gene functions in potato and tobacco. Transgenic tobacco and potato plants carrying Cf-9 exhibit a rapid hypersensitive cell death response (HR) to Avr 9 peptide injection. Cf 9 tobacco plants were reciprocally crossed to Avr9-producing tobacco. A developmentally regulated seedling lethal phenotype occurred in F 1 progeny when Cf9 was used as the male parent and Avr9 as the female parent. However, when Cf9 was inherited in the maternal tissue and a heterozygous Avr9 plant was used as the pollen donor, a much earlier reaction was caused, leading to no germination of any F 1 seed. Detailed analysis of the Avr9-induced responses in Cf9 tobacco leaves revealed that (1) most mesophyll cells died within 3 hr (compared with 12 to 16 hr in tomato); (2) the macroscopic HR was visible at an Avr9 titer five times lower than that which caused visible symptoms in tomato; (3) the HR invariably extended into noninjected panels of the tobacco leaf; (4) no HR occurred in leaves of young tobacco plants; (5) in older plants, the HR was dramatically enhanced by sequential Avr 9 challenges; and (6) coexpression of a salicylate hydroxylase transgene ( nahG ) from Pseudomonas putida reduced the severity of the macroscopic leaf HR and also restored germination to Cf9 ؋ 35S:Avr9 F 1 seedlings. Simultaneous introduction of Cf-9 homologs ( Hcr9-9 genes A and B or D) along with the native Cf-9 gene did not alter the responses that were specifically induced by Avr9. Various ways to use the Cf-9-Avr9 gene combination to engineer broad-spectrum disease resistance in several solanaceous species are discussed.

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“…With the development of the X-ray topographic method in the 1970s, dislocations located on various planes within single ice crystals were observed (e.g., Webb and Hayes 1967;Fukuda et al 1987;Duval et al 1983;Baker 1997). The most significant finding from these studies was the remarkable anisotropy in the plastic deformation of ice, such that the creep rate by slip on the basal plane (in particular, the so-called glide set of basal planes; Whitworth 1980) is roughly 10 4 times faster, at a given stress, than creep by non-basal slip.…”

Section: Dislocation-driven Attenuationmentioning

confidence: 99%