scholarly journals STUDIES ON THE MECHANISM OF TRANSDUCTION BY BACTERIOPHAGE ϕγ. II. FORMATION OF TRANSDUCING ELEMENTS

Genetics ◽  
1980 ◽  
Vol 95 (3) ◽  
pp. 525-544
Author(s):  
Jean-Pierre Gratia
Keyword(s):  
Phage Genome ◽  
Initiation Site ◽  
Specific Point ◽  
Genome Packaging ◽  
Linear Fashion ◽  
A Site

ABSTRACT The formation of the transducing elements (TE) of bacteriophage ɸγ, analyzed in lysogens of the thermo-inducible derivative ɸγhyI, has been found to parallel the formation of plaque-forming particles with a frequency of 2 × 10-2 TE/PFU, but is more sensitive to temperature and to UV. Deletion of one of the prophage termini (attR) prevents normal excision and formation of plaque-forming particles, but does not affect the formation of transducing elements, which arise at a rate of nearly 10-1 TE per induced bacterium. Transducing elements would be formed by in situ encapsulation of a hybrid segment from a specific point in the induced prophage, possibly the presumed packaging initiation site of the normal phage genome, before excision of the latter has occurred. Analysis of the mechanism of transduction to partly heterologous lysogens has revealed the participation of a co-infecting genome arranged in a linear fashion and has given evidence for a permutation in the sequence of transducing and nontransducing genomes. The data are consistent with a mechanism of encapsidation distinct from the Ter system even for hybrids inheriting part of the ɸ80 genome, but endowed with the property to form transducing elements like those of ɸγ. Upon infection, transducing elements are formed after one cycle of lytic development with the same characteristics as those resulting from induction, but with a frequency 50 to 100 times lower. This process is dependent on the efficiency of Int promoted recombination. Superinfection experiments performed under conditions preventing Int promoted recombination reveal that any superinfecting ɸγ can promote the formation of transducing particles, depending on the presence within the host prophage of a site from which transducing genome packaging initiates.

scholarly journals Development of Fragility Curves for Piping and Slope Stability of River Levees

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 738
Author(s):  
Nicola Rossi ◽  
Mario Bačić ◽  
Meho Saša Kovačević ◽  
Lovorka Librić
Keyword(s):  
Slope Stability ◽  
Fragility Curves ◽  
Safety Margin ◽  
Water Levels ◽  
Flood Event ◽  
Soil Parameters ◽  
Design Code ◽  
A Site ◽  
Insight Into

The design code Eurocode 7 relies on semi-probabilistic calculation procedures, through utilization of the soil parameters obtained by in situ and laboratory tests, or by the means of transformation models. To reach a prescribed safety margin, the inherent soil parameter variability is accounted for through the application of partial factors to either soil parameters directly or to the resistance. However, considering several sources of geotechnical uncertainty, including the inherent soil variability, measurement error and transformation uncertainty, full probabilistic analyses should be implemented to directly consider the site-specific variability. This paper presents the procedure of developing fragility curves for levee slope stability and piping as failure mechanisms that lead to larger breaches, where a direct influence of the flood event intensity on the probability of failure is calculated. A range of fragility curve sets is presented, considering the variability of levee material properties and varying durations of the flood event, thus providing crucial insight into the vulnerability of the levee exposed to rising water levels. The procedure is applied to the River Drava levee, a site which has shown a continuous trend of increased water levels in recent years.

scholarly journals Serous Tubal Intraepithelial Carcinoma or Not? Metastases to Fallopian Tube Mucosa Can Masquerade as In Situ Lesions

2017 ◽  
Vol 141 (10) ◽  
pp. 1313-1315 ◽  
Author(s):  
Reena Singh ◽  
Kathleen R. Cho
Keyword(s):  
Fallopian Tube ◽  
De Novo ◽  
Data Sources ◽  
High Grade ◽  
Serous Tubal Intraepithelial Carcinoma ◽  
Different Types ◽  
Intraepithelial Carcinoma ◽  
A Site ◽  
Immunohistochemical Stains

Context.— Nonuterine high-grade serous carcinomas (HGSCs) are believed to arise most often from precursors in the fallopian tube referred to as serous tubal intraepithelial carcinomas (STICs). A designation of tubal origin has been suggested for all cases of nonuterine HGSC if a STIC is identified. Objective.— To highlight that many different types of nongynecologic and gynecologic carcinomas, including HGSC, can metastasize to the tubal mucosa and mimic de novo STIC. Data Sources.— A mini-review of several recently published studies that collectively examine STIC-like lesions of the fallopian tube. Conclusions.— The fallopian tube mucosa can be a site of metastasis from carcinomas arising elsewhere, and pathologists should exercise caution in diagnosing STIC without first considering the possibility of metastasis. Routinely used immunohistochemical stains can often be used to determine if a STIC-like lesion is tubal or nongynecologic in origin. In the context of uterine and nonuterine HGSC, STIC may represent a metastasis rather than the site of origin, particularly when widespread disease is present.

scholarly journals Exploring the Utility of Compound-Specific Isotope Analysis for Assessing Ferrous Iron-Mediated Reduction of RDX in the Subsurface

2020 ◽  
Author(s):  
Yiran Tong ◽  
Matthew J. Berens ◽  
Bridget A. Ulrich ◽  
Jakov Bolotin ◽  
Jennifer H. Strehlau ◽  
...  
Keyword(s):  
Groundwater Contamination ◽  
Ferrous Iron ◽  
Chemical Reduction ◽  
Isotope Analysis ◽  
Enrichment Factors ◽  
Isotope Enrichment ◽  
Compound Specific Isotope Analysis ◽  
A Site ◽  
Mediated Reduction

This work determines isotope enrichment factors for RDX during reduction by iron minerals. The values determined are used to assess the transformation of RDX at a site with groundwater contamination and in laboratory column reactors simulating in situ chemical reduction treatment.

scholarly journals Benthic nutrient fluxes and sediment oxygen consumption in a full-scale facultative pond in Patagonia, Argentina

2013 ◽  
Vol 68 (8) ◽  
pp. 1770-1777 ◽  
Author(s):  
M. Faleschini ◽  
J. L. Esteves
Keyword(s):  
Oxygen Consumption ◽  
Advanced Degree ◽  
Benthic Fluxes ◽  
Temperate Region ◽  
Benthic Metabolism ◽  
Mineralization Of Organic Matter ◽  
A Site ◽  
Water Bottom ◽  
Raw Wastewater

The study of benthic metabolism is an interesting tool to understand the process that occurs in bottom water at wastewater stabilization ponds. Here, rates of benthic oxygen consumption and nutrient exchange across the water–sludge interface were measured in situ using a benthic chamber. The research was carried out during autumn, winter, and summer at a municipal facultative stabilization pond working in a temperate region (Puerto Madryn city, Argentina). Both a site near the raw wastewater inlet (Inlet station) and a site near the outlet (Outlet station) were sampled. Important seasonal and spatial patterns were identified as being related to benthic fluxes. Ammonium release ranged from undetectable (autumn/summer – Inlet station) to +30.7 kg-NH4+ ha−1 d−1 (autumn – Outlet station), denitrification ranged from undetectable (winter – in both sites) to −4.0 kg-NO3− ha−1 d−1 (autumn – Outlet station), and oxygen consumption ranged from 0.07 kg-O2ha−1 d−1 (autumn/summer – Outlet station) to 0.84 kg-O2ha−1 d−1 (autumn – Inlet station). During the warmer months, the mineralization of organic matter from the bottom pond acts as a source of nutrients, which seem to support the important development of phytoplankton and nitrification activity recorded in the surface water. Bottom processes could be related to the advanced degree and efficiency of the treatment, the temperature, and probably the strong and frequent wind present in the region.

Mn-Mg disordering in cummingtonite: a high-temperature neutron powder diffraction study

2000 ◽  
Vol 64 (2) ◽  
pp. 255-266 ◽  
Author(s):  
J. J. Reece ◽  
S. A. T. Redfern ◽  
M. D. Welch ◽  
C. M. B. Henderson
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
New York ◽  
High Temperature ◽  
Powder Diffraction ◽  
Elevated Temperatures ◽  
Neutron Powder Diffraction ◽  
Site Preference ◽  
A Site

AbstractThe crystal structure of a manganoan cummingtonite, composition [M4](Na0.13Ca0.41Mg0.46Mn1.00) [M1,2,3](Mg4.87Mn0.13)(Si8O22)(OH)2, (Z = 2), a = 9.5539(2) Å, b = 18.0293(3) Å, c = 5.2999(1) Å, β = 102.614(2)° from Talcville, New York, has been refined at high temperature using in situ neutron powder diffraction. The P21/m to C2/m phase transition, observed as spontaneous strains +ε1 = −ε2, occurs at ˜107°C. Long-range disordering between Mg2+ and Mn2+ on the M(4) and M(2) sites occurs above 550°C. Mn2+ occupies the M(4) and M(2) sites preferring M(4) with a site-preference energy of 24.6±1.5 kJ mol−1. Disordering induces an increase in XMnM2 and decrease in XMnM4 at elevated temperatures. Upon cooling, the ordered states of cation occupancy are ‘frozen in’ and strains in lattice parameters are maintained, suggesting that re-equilibration during cooling has not taken place.

A site-based approach to delivering rangeland ecosystem services

2011 ◽  
Vol 33 (2) ◽  
pp. 99 ◽  
Author(s):  
Joel Brown ◽  
Neil MacLeod
Keyword(s):  
Ecosystem Services ◽  
Multiple Scales ◽  
Soil Surface ◽  
Wildlife Habitat ◽  
Climate Mitigation ◽  
Ecological Sites ◽  
Ecological Site ◽  
State And Transition Model ◽  
A Site

Rangeland ecosystems are capable of providing an array of ecosystem services important to the wellbeing of society. Some of these services (e.g. meat, fibre) are transported to markets and their quantity, quality and value are established via a set of widely accepted standards. Other services (e.g. climate mitigation, water quality, wildlife habitat) do not leave the land, but are, in fact, most valuable when they remain in situ. Determining their quantity, quality and value presents a challenge that must be met if there is to be a credible, accessible ecosystem services market for rangelands. In this paper we describe some of the ecosystem services that may be extracted from rangelands, discuss their unique ecological nature and relate those unique ecological properties to soil and vegetation attributes that can serve as a basis for measurement, both quality and quantity. We suggest the use of a soil/vegetation-based system in which similar climate, geomorphology and edaphic properties are grouped into ecological sites based on their response to disturbance. Within each ecological site, a unique state and transition model describes the dynamics of vegetation and soil surface properties, provides state indicators (vegetation structure, soil properties), predicts ecosystem services that may be derived at multiple scales, and organises information related to management to achieve ecosystem service objectives, including sustainability.

Aspects of the palaeontology of Salthill Quarry, Clitheroe, Lancashire (Mississippian), NW England

2020 ◽  
Vol 63 (3) ◽  
pp. pygs2020-003
Author(s):  
Stephen K. Donovan ◽  
Andrew Tenny
Keyword(s):  
Scientific Interest ◽  
Decapod Crustaceans ◽  
Southern Margin ◽  
Rugose Corals ◽  
Special Scientific ◽  
Dense Cluster ◽  
A Site ◽  
A Current

Salthill Quarry, Clitheroe, Lancashire (Mississippian, early Visean, Chadian) is a Site of Special Scientific Interest on the basis of its diverse fauna of invertebrates preserved in a Waulsortian mud mound setting. Important new specimens are described from the limestones and thin mudstones of the Hodder Mudstone Formation, on the southern margin of the quarry. A rare echinoid, archaeocidarid? gen. et sp. indet., is incomplete, but unusually retains the original curvature of the test. A columnal of Bystrowicrinus (col.) westheadi Donovan was derived from a radicular runner and has a dense cluster of radice scars on one side only. The columnal had a wedge-like section, thus suggesting a curvature of the stem. A cluster of solitary rugose corals on the base of a limestone bed includes at least two geniculated specimens in life position, the calice raised above the base of the bed. This is more likely to be due to burial in situ than a current accumulation. Ostiocavichnus Bohatý et al. is not an ichnotaxon, but a palaeopathology identified as a swollen crinoid pluricolumnal; broadly analogous structures are identified in fossil decapod crustaceans.

Evaluation of an in situ early life stage test with cutthroat trout, Oncorhynchus clarki, for environmental monitoring – a case study using mine effluent

2013 ◽  
Vol 49 (2) ◽  
pp. 95-103 ◽  
Author(s):  
B. Chalmers ◽  
J. Elphick ◽  
G. Gilron ◽  
H. Bailey
Keyword(s):  
Early Life ◽  
Life Stage ◽  
Cutthroat Trout ◽  
Early Life Stage ◽  
Exposure Period ◽  
Low Flow ◽  
Treated Effluent ◽  
Mine Effluent ◽  
A Site

This study evaluated an in situ early life stage test using cutthroat trout for potential use in Canada's Metal Mines Effluent Regulations' Environmental Effects Monitoring (EEM) program. Current field monitoring approaches focus on either adult fish surveys or mesocosm studies, but both of these have inherent limitations that may affect their suitability on a site-specific basis. This study evaluated an alternative approach, namely an in situ toxicity test, as part of an EEM program for a zinc, copper and gold mine. Hatchboxes containing cutthroat trout embryos were placed in a creek that receives treated effluent from the mine, and monitored through the swim-up stage to evaluate hatching success, survival, normal development and growth. Advantages of the method include: no feeding requirement during exposure, fixed exposure locations, relevant endpoints and high statistical sensitivity. In addition, the extended exposure period integrated long-term exposure variables, including low-flow and freshet events. This approach also has application to other salmonid species and types of discharges.

scholarly journals MEASUREMENTS OF FORCES ON DOLOS ARMOR UNITS AT PROTOTYPE SCALE

1988 ◽  
Vol 1 (21) ◽  
pp. 174 ◽  
Author(s):  
Gary L. Howell
Keyword(s):  
Degrees Of Freedom ◽  
Bottom Layer ◽  
Core Material ◽  
Crescent City ◽  
Side Scan Sonar ◽  
Six Degrees Of Freedom ◽  
Wave Measurements ◽  
A Site ◽  
Wave Induced

In-situ measurements of the structural bending moments and torque about the shank-fluke interface of the dolos armor unit have been made for 42-ton (36-metric tonne) dolosse at Crescent City, California jetty. The measurements include the static loads on the dolosse as well as wave induced forces. The data were obtained from internal strain gages cast into the dolos during construction along with a special data acquisition system. The measurement system was also capable of capturing impact forces caused by dolos rocking or movement. Measurements were made during the winter storm seasons from January 1987 through May 1988. Coincident with the structural measurements, wave height and period were measured at several water depths approaching the breakwater, including a site directly in front of the dolos test section. The Crescent City jetty is a shallow water breakwater with depth limited waves in about 10 meters of water depth. The structural measurements were made from 14 dolos units arranged in a rectangular section on the top layer of the trunk portion of the jetty. Four of these dolosse are also instrumented with an accelerometer platform to measure motion with six degrees of freedom. In addition, there are three instrumented dolosse on the bottom layer of the breakwater. These dolosse measure the static stress due to the units placed on top of them, as well as pulsating forces. The structural and wave measurements, reported here, are supplemented with hydrostatic pore pressure measurements in the core material of the breakwater, and by aerial photogrammetric motion analysis (Kendall, 1988), land based surveys, boudary condition surveys, hydrographic surveys, and side scan sonar surveys.

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