Invasive Potamopyrgus antipodarum (New Zealand mud snails) and native snails differ in sensitivity to specific electrical conductivity and cations

2019 ◽  
Vol 54 (1) ◽  
pp. 103-117 ◽  
Author(s):  
Michele D. Larson ◽  
Janet C. Dewey ◽  
Amy C. Krist
Keyword(s):  
Electrical Conductivity ◽  
New Zealand ◽  
Potamopyrgus Antipodarum ◽  
Specific Electrical Conductivity

Electrical Conductivity of Agricultural Drainage Water in Iowa

2017 ◽  
Vol 33 (3) ◽  
pp. 369-378 ◽  
Author(s):  
Brett A Zimmerman ◽  
Amy L Kaleita
Keyword(s):  
Electrical Conductivity ◽  
Environmental Conditions ◽  
Major Ions ◽  
Ionic Composition ◽  
Field Investigation ◽  
Drainage Water ◽  
Specific Electrical Conductivity ◽  
Agricultural Drainage ◽  
Bulk Electrical Conductivity ◽  
Drainage Waters

Abstract. Assessing the effectiveness of management strategies to reduce agricultural nutrient efflux is hampered by the lack of affordable, continuous monitoring systems. Generalized water quality monitoring is possible using electrical conductivity. However environmental conditions can influence the ionic ratios, resulting in misinterpretations of established electrical conductivity and ionic composition relationships. Here we characterize specific electrical conductivity (k25) of agricultural drainage waters to define these environmental conditions and dissolved constituents that contribute to k25. A field investigation revealed that the magnitude of measured k25 varied from 370 to 760 µS cm-1. Statistical analysis indicated that variability in k25 was not correlated with drainage water pH, temperature, nor flow rate. While k25 was not significantly different among drainage waters from growing and post-growing season, significant results were observed for different cropping systems. Soybean plots in rotation with corn had significantly lower conductivities than those of corn plots in rotation with soybeans, continuous corn plots, and prairie plots. In addition to evaluating k25 variability, regression analysis was used to estimate the concentration of major ions in solution from measured k25. Regression results indicated that HCO3-, Ca2+, NO3-, Mg2+, Cl-, Na2+, SO42- were the major drainage constituents contributing to the bulk electrical conductivity. Calculated ionic molal conductivities of these analytes suggests that HCO3-, Ca2+, NO3-, and Mg2+ account for approximately 97% of the bulk electrical conductivity. Keywords: Electrical conductivity, Salinity, Subsurface drainage, Total dissolved solids.

scholarly journals The effect of essential oils on quality and safety parameters of meat during its storage

2021 ◽  
Vol 6 (1) ◽  
pp. 97-104
Author(s):  
A. U. Shkabrou ◽  
V. D. Raznichenka ◽  
L. Y. Kharkevich
Keyword(s):  
Electrical Conductivity ◽  
Essential Oils ◽  
Muscle Tissue ◽  
Structural Changes ◽  
Control Sample ◽  
Water Extract ◽  
Storage Period ◽  
Specific Electrical Conductivity ◽  
Complete Disappearance ◽  
Quality Indices

This article researches the basic principles of mechanism for finding the concentrations of essential oils (EO) which are efficient for antimicrobial action, when used as a natural alternative to synthetic analogues. The effect of EO of rosemary, sage, garlic, laurel, cloves, basil and thyme on the structural components of meat, its physical and chemical, organoleptic and microbiological quality indices was studied. The effect of EO on duration of microorganisms’ growth phases is analyzed. It is shown that the reasonable concentration of the essential-oil mixture (EOM) is equal to 0.1%, since at this concentration the optimal inhibition of saprophytic microflora was provided with satisfactory organoleptic quality indices (“taste peculiar for this type of product”, “pleasant fragrance”, “spicy aroma”). The analysis of histological structural changes in muscle tissue showed that application of EOM slows down autolytic processes, which correlates with the data obtained in research of the specific electrical conductivity in water extracts from the muscle tissue. The autolysis process in the control samples was more intensive in comparison with the experimental samples stored in the EOM. Thus, by 84th hour of storage in the control sample the basophilic staining of the samples slices was observed, as well as almost complete disappearance of the striation of muscle fibers. In the muscle tissue slices the disintegration of individual fragments into myofibrils, and myofibrils into sarcomeres, was observed in form of a granular mass, sometimes enclosed in endomysium. The meat fibers were deformed and their separation was observed. The same changes with the studied samples stored in the EOM occurred only after 204 hours of storage. The above studies of changes in the specific electrical conductivity of water extract from meat during storage showed the presence of complexes of EOM components formed with proteins and lipids of muscle tissue. The obtained data are confirmed by histological studies. Thus, the use of EOM allowed elongation of the cold storage period of semi-finished natural lump products by 2.6 times, which proves the practical benefits of its use in the meat-processing industry.

scholarly journals Range extension of the invasive Potamopyrgus antipodarum (Gray, 1843) (Gastropoda, Tateidae) in Chile, and a summary of its distribution in the country

Check List ◽  
2020 ◽  
Vol 16 (3) ◽  
pp. 621-626 ◽  
Author(s):  
Gonzalo A. Collado ◽  
Carmen G. Fuentealba
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
New Zealand ◽  
South America ◽  
River Basin ◽  
Dna Barcode ◽  
Potamopyrgus Antipodarum ◽  
Range Extension ◽  
First Time ◽  
Scanning Electron

The New Zealand mudsnail Potamopyrgus antipodarum (Gray, 1843) has been considered as one of the most invasive mollusks worldwide and recently was listed among the 50 most damaging species in Europe. In the present paper, we report for the first time the presence of P. antipodarum in the Maule river basin, Chile. The identity of the species was based on anatomical microdissections, scanning electron microscopy comparisons, and DNA barcode analysis. This finding constitutes the southernmost record of the species until now in this country and South America.

scholarly journals Interactions Between the Invasive New Zealand Mudsnail (Potamopyrgus Antipodarum) and a Native Snail (Fossaria Bakerilymnaea Bulimoides Group) in the Greater Yeelowstone

2011 ◽  
Vol 33 ◽  
pp. 161-170
Author(s):  
Heather Thon ◽  
Amy Krist
Keyword(s):  
Invasive Species ◽  
New Zealand ◽  
American West ◽  
Biological Diversity ◽  
Potamopyrgus Antipodarum ◽  
The Past ◽  
Conservation Concern ◽  
And Function ◽  
New Zealand Mud Snail ◽  
The Impact

Understanding invasive species impacts is critical to determining how an ecosystem may function after an introduction. Invasive species can alter the structure and function of ecosystems, reduce biological diversity, and alter communities through predation, facilitation and competition. In the past 30 years, the invasive New Zealand mud snail (Potamopyrgus antipodarum) has established in areas of conservation concern in the American West including Yellowstone National Park. To develop a greater understanding of the impact of P. antipodarum on the native co-occurring snail, Fossaria (Bakerilymnaea) bulimoides group, we conducted two experiments to assess the interactions occurring between these snails. We found that F. bulimoides growth was reduced by all interactors, but especially by P. antipodarum. In addition, growth of F. bulimoides was much more affected by high biomass of snails than P. antipodarum. P. antipodarum grew more in the presence of interactors and their growth was facilitated by the presence of the native snail F. bulimoides.

scholarly journals A Method For Determination Of Specific Electrical Resistance Of Steel And Nano-Coating Sputtered On It

2015 ◽  
Vol 2 ◽  
pp. 118 ◽  
Author(s):  
Andris Martinovs ◽  
Josef Timmerberg ◽  
Konstantins Savkovs ◽  
Aleksandrs Urbahs ◽  
Paul Beckmann
Keyword(s):  
Electrical Conductivity ◽  
Magnetic Permeability ◽  
Electrical Resistance ◽  
Skin Effect ◽  
Specific Electrical Resistance ◽  
Specific Electrical Conductivity ◽  
Relative Magnetic Permeability ◽  
Nano Coating ◽  
Cylindrical Steel

The paper describes methods developed to determine specific electrical conductivity and relative magnetic permeability of cylindrical steel items and nano-coatings deposited on them by sputtering. Research enables development of a new method for determination of thickness of vacuum deposited nano- coating that is based on application of skin effect.

scholarly journals Dielectric properties of the system: 4-n-pentyloxybenzoic acid– N-(4-n-butyloxybenzylidene)-4᾽-methylaniline

2021 ◽  
Vol 16 (2) ◽  
pp. 138-147
Author(s):  
S. A. Syrbu ◽  
M. S. Fedorov ◽  
E. A. Lapykina ◽  
V. V. Novikov
Keyword(s):  
Crystal Structure ◽  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Anisotropy ◽  
Specific Electrical Conductivity ◽  
Conductivity Anisotropy ◽  
Independent Molecules ◽  
System Properties ◽  
The Individual

Objectives. Our aim was to study the dielectric properties of the 4-n-pentyloxybenzoic acid– N-(4-n-butyloxybenzylidene)-4’-methylaniline system and reveal how different concentrations of N-(4-n-butyloxybenzylidene)-4’-methylaniline additives affect the dielectric properties of 4-n-pentyloxybenzoic acid.Methods. System properties were investigated using polarization thermomicroscopy and dielcometry.Results. We found that dielectric anisotropy changes its sign from positive to negative at the transition temperature of the high-temperature nematic subphase to the low-temperature one. The anisotropy of the dielectric constant of N-4-n-butoxybenzylidene-4’-methylaniline has a positive value and increases as to the system approaches the crystalline phase. The crystal structure of the 4-n-pentyloxybenzoic acid contains dimers formed by two independent molecules due to a pair of hydrogen bonds. The crystal structure of N-(4-n-butoxybenzylidene)-4’-methylaniline contains associates formed by orientational interactions of two independent molecules. 4-n-Pentyloxybenzoic acid dimers (270 nm) and associates of N-4-n-butoxybenzylidene-4’- methylaniline (250 nm) proved to have approximately the identical length. Considering the close length values of the structural units of both compounds and the dielectric anisotropy sign, we assume that the N-4-n-butoxybenzylidene-4’-methylaniline associates are incorporated into the supramolecular structure of the 4-n-pentyloxybenzoic acid. The specific electrical conductivity of the compounds under study lies between 10−7 and 10−12 S∙cm−1. The relationship between the specific electrical conductivity anisotropy and the system composition in the nematic phase at the identical reduced temperature, obtained between 100 and 1000 Hz is symbatic. However, the electrical conductivity anisotropy values of the system obtained at 1000 Hz are lower compared to those obtained at 100 Hz. At N-(4-n-butoxybenzylidene)-4’-methylaniline concentrations between 30 and 60 mol %, the electrical conductivity anisotropy values are higher than those of the individual component.Conclusions. A change in the sign of the dielectric constant anisotropy of the 4-n-pentyloxybenzoic acid during nematic subphase transitions was established. We showed that the system has the highest dielectric constant anisotropy value when components have an equal number of moles. Highest electrical conductivity anisotropy values are observed when the concentration of the N-4-n-butoxybenzylidene-4᾽-methylaniline system lies between 30 and 60 mol %. 

scholarly journals STUDY OF THE PROGRESS OF SEAWATER INTRUSION WITHIN A PLAIN AREA OF RHODOPE PREFECTURE

2004 ◽  
Vol 36 (4) ◽  
pp. 2057 ◽  
Author(s):  
Φ. Πλιάκας ◽  
I. Διαμαντής ◽  
A. Καλλιώρας ◽  
Χ. Πεταλάς
Keyword(s):  
Electrical Conductivity ◽  
Grain Size ◽  
Seawater Intrusion ◽  
Groundwater Level ◽  
Specific Electrical Conductivity ◽  
Chemical Analyses ◽  
Conductivity Measurements ◽  
Groundwater Level Fluctuations ◽  
Plain Area ◽  
Groundwater Samples

This paper investigates the progress of seawater intrusion within the plain area of Xylagani - Imeros, in SW part of Rhodope Prefecture, as well as the suitability of groundwater for several purposes, after qualitative valuation of groundwater samples from selective wells of the study area. The conclusions also include some managerial suggestions for the confrontation of seawater intrusion. The investigation in question took place between 1994-1997 and 2002-2003, and involves the installation of piezometric wells, geoelectric sounding measurements, grain size analyses, monitoring of the groundwater level fluctuations in selective wells, specific electrical conductivity measurements and chemical analyses of water samples from selective wells of the study area.

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