scholarly journals Recolonization by Slugs: Vertical and Horizontal Dispersal by the Field Slug, Deroceras reticulatum

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 531
Author(s):  
Gordon Port ◽  
Alan Craig ◽  
Mark Shirley
Keyword(s):  
Significant Contribution ◽  
Vertical Movement ◽  
Deroceras Reticulatum ◽  
Ecological Mechanisms ◽  
A Site ◽  
Grassland Site

Following treatment with molluscicides or other controls, slugs can recolonize a site very quickly, but the proportion of the colonizing slugs moving from adjacent areas (horizontal dispersal) and the proportion from within the soil (vertical dispersal) has not previously been established. At a grassland site, barriers were used to exclude and trap slugs in order to estimate horizontal and vertical movement over a period of 32 months. For the first 15 months vertical movement made a significant contribution to the slugs recolonizing a grassland area. The ecological mechanisms occurring and the implications for the control of slugs are discussed.

Chlorsulfuron residues are not accumulating in soils of southern Queensland

1996 ◽  
Vol 36 (2) ◽  
pp. 223 ◽  
Author(s):  
SR Walker ◽  
GR Robinson
Keyword(s):  
Agricultural Soils ◽  
Climatic Factors ◽  
Vertical Movement ◽  
Winter Cereal ◽  
Stubble Retention ◽  
Applied Dose ◽  
Residue Concentration ◽  
A Site ◽  
Residual Herbicide ◽  
Summer Fallow

Chlorsulfuron persistence was measured in soils (to a depth of 150 cm) at 4 sites in the winter cereal region of southern Queensland. The residual herbicide had been applied 6-14 times in the previous 7-14 years. Residues here measured using a bioassay based on suppression of root growth of maize (Zea mays cv. GH5010). Less than 3% of the total applied chlorsulfuron (96-210 g a.i./ha) was detected 6-12 months after the last application, and residues were <0.7 ng/g soil in the surface 30 cm, and <0.3 ng/g below 30 cm. The limited vertical movement of residues was associated with the herbicide being applied in early winter, several months before leaching rains. Changes in residue concentration with time were also measured at a site in central Queensland, and in a fallow management experiment in southern Queensland. Persistence was greater at the cooler, drier site in southern Queensland than in central Queensland; 4544% compared with 3 4 % of applied dose remained 3 months after application respectively. Stubble retention had no effect on persistence, but tillage during the summer fallow increased persistence slightly. There was no evidence of chlorsulfuron residues accumulating and only limited leaching in these alkaline agricultural soils of southern Queensland. Persistence within a season was influenced by soil and climatic factors.

Eels Under Standing Wave Conditions

1982 ◽  
Vol 40 ◽  
pp. 492-495
Author(s):  
O.L. Krivanek ◽  
J. TaftØ
Keyword(s):  
Standing Wave ◽  
Wave Conditions ◽  
Set Up ◽  
A Site ◽  
Complex Crystal

It is well known that a standing electron wavefield can be set up in a crystal such that its intensity peaks at the atomic sites or between the sites or in the case of more complex crystal, at one or another type of a site. The effect is usually referred to as channelling but this term is not entirely appropriate; by analogy with the more established particle channelling, electrons would have to be described as channelling either through the channels or through the channel walls, depending on the diffraction conditions.

Head Size and DNA Content in Bacteriophage T4

1972 ◽  
Vol 30 ◽  
pp. 200-201
Author(s):  
Fred Eiserling ◽  
A. H. Doermann ◽  
Linde Boehner
Keyword(s):  
Electron Microscopy ◽  
Dna Content ◽  
Bacteriophage T4 ◽  
Head Size ◽  
Virus Particles ◽  
Altered Protein ◽  
A Cell ◽  
Bacterial Viruses ◽  
A Site ◽  
Protein Shell

The control of form or shape inheritance can be approached by studying the morphogenesis of bacterial viruses. Shape variants of bacteriophage T4 with altered protein shell (capsid) size and nucleic acid (DNA) content have been found by electron microscopy, and a mutant (E920g in gene 66) controlling head size has been described. This mutant produces short-headed particles which contain 2/3 the normal DNA content and which are non-viable when only one particle infects a cell (Fig. 1).We report here the isolation of a new mutant (191c) which also appears to be in gene 66 but at a site distinct from E920g. The most striking phenotype of the mutant is the production of about 10% of the phage yield as “giant” virus particles, from 3 to 8 times longer than normal phage (Fig. 2).

Stabilizing pyritic material

1989 ◽  
Vol 4 ◽  
pp. 244-248 ◽  
Author(s):  
Donald L. Wolberg
Keyword(s):  
Significant Contribution ◽  
Organic Materials ◽  
Sedimentary Rocks ◽  
Iron Sulfides ◽  
Decomposition Products ◽  
Iron Minerals ◽  
Pyrite Formation ◽  
Organic Sediments ◽  
Freshwater Environments

The minerals pyrite and marcasite (broadly termed pyritic minerals) are iron sulfides that are common if not ubiquitous in sedimentary rocks, especially in association with organic materials (Berner, 1970). In most marine sedimentary associations, pyrite and marcasite are associated with organic sediments rich in dissolved sulfate and iron minerals. Because of the rapid consumption of sulfate in freshwater environments, however, pyrite formation is more restricted in nonmarine sediments (Berner, 1983). The origin of the sulfur in nonmarine environments must lie within pre-existing rocks or volcanic detritus; a relatively small, but significant contribution may derive from plant and animal decomposition products.

Exploration-Stage Implementation Variation

2014 ◽  
Vol 222 (1) ◽  
pp. 37-48 ◽  
Author(s):  
Stephanie Romney ◽  
Nathaniel Israel ◽  
Danijela Zlatevski
Keyword(s):  
Parent Training ◽  
Average Cost ◽  
Cost Savings ◽  
Training Group ◽  
Group Differences ◽  
Triple P ◽  
Community Based ◽  
Parent Training Program ◽  
A Site ◽  
The Cost

The present study examines the effect of agency-level implementation variation on the cost-effectiveness of an evidence-based parent training program (Positive Parenting Program: “Triple P”). Staff from six community-based agencies participated in a five-day training to prepare them to deliver a 12-week Triple P parent training group to caregivers. Prior to the training, administrators and staff from four of the agencies completed a site readiness process intended to prepare them for the implementation demands of successfully delivering the group, while the other two agencies did not complete the process. Following the delivery of each agency’s first Triple P group, the graduation rate and average cost per class graduate were calculated. The average cost-per-graduate was over seven times higher for the two agencies that had not completed the readiness process than for the four completing agencies ($7,811 vs. $1,052). The contrast in costs was due to high participant attrition in the Triple P groups delivered by the two agencies that did not complete the readiness process. The odds of Triple P participants graduating were 12.2 times greater for those in groups run by sites that had completed the readiness process. This differential attrition was not accounted for by between-group differences in participant characteristics at pretest. While the natural design of this study limits the ability to empirically test all alternative explanations, these findings indicate a striking cost savings for sites completing the readiness process and support the thoughtful application of readiness procedures in the early stages of an implementation initiative.

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