scholarly journals Impact of secondary salinisation on the structure and diversity of oligochaete communities

2020 ◽  
pp. 6
Author(s):  
Agnieszka Sowa ◽  
Mariola Krodkiewska
Keyword(s):  
Salinity Gradient ◽  
Significant Loss ◽  
Taxa Richness ◽  
Secondary Salinisation ◽  
Upper Silesian Coal Basin ◽  
Saline Rivers ◽  
Elevated Water ◽  
Inland Water Bodies ◽  
Potamothrix Hammoniensis ◽  
Freshwater Oligochaetes

Secondary salinisation has become one of the most important factors responsible for changes in the aquatic biota. Earlier research has focused on macroinvertebrates including oligochaetes in anthropogenically saline rivers and streams, but studies on oligochaetes in anthropogenically saline stagnant waters remain scarce. Therefore, this study was conducted to assess changes in the species composition as well as the abundance and biomass of oligochaete communities along a large salinity gradient in the anthropogenic inland water bodies located in the Upper Silesian Coal Basin (Southern Poland), which is one of the largest coal basins in Europe. Herein, a total of 27 oligochaete species including five alien species were assessed, namely, Potamothrix bavaricus, Potamothrix hammoniensis, Potamothrix moldaviensis, Psammoryctides albicola, and Psammoryctides barbatus. The results confirmed that the freshwater oligochaetes could tolerate elevated water salinity and showed highest densities and taxa richness in intermediate salinity. Moreover, the waters with the highest salinity had an extremely low number of oligochaete species. A salinity level above 2800 mg L−1 led to significant loss of diversity of the oligochaetes, and consequently, these habitats were colonized by halotolerant species, especially Paranais litoralis, whose abundance increased with increasing salinity gradient.

scholarly journals Response of the mollusc communities to environmental factors along an anthropogenic salinity gradient

2019 ◽  
Vol 106 (11-12) ◽  
Author(s):  
Agnieszka Sowa ◽  
Mariola Krodkiewska ◽  
Dariusz Halabowski ◽  
Iga Lewin
Keyword(s):  
Alien Species ◽  
Nitrate Nitrogen ◽  
Salinity Gradient ◽  
Ammonium Nitrogen ◽  
Freshwater Ecosystems ◽  
Underground Coal Mining ◽  
Taxa Richness ◽  
Elevated Salinity ◽  
Large Gradient ◽  
Sand And Gravel

AbstractAnthropogenic salinisation of freshwater ecosystems is frequent across the world. The scale of this phenomenon remains unrecognised, and therefore, monitoring and management of such ecosystems is very important. We conducted a study on the mollusc communities in inland anthropogenic ponds covering a large gradient of salinity located in an area of underground coal mining activity. A total of 14 gastropod and 6 bivalve species were noted. No molluscs were found in waters with total dissolved solids (TDS) higher than 17.1 g L−1. The share of alien species in the communities was very high in waters with elevated salinity and significantly lower in the freshwaters. Canonical correspondence analysis (CCA) showed that TDS, pH, alkalinity, nitrate nitrogen, ammonium nitrogen, iron, the content of organic matter in sediments, the type of substrate and the content of sand and gravel in sediments were the variables that were significantly associated with the distribution of molluscs. The regression analysis revealed that total mollusc density was positively related to alkalinity and negatively related to nitrate nitrogen. The taxa richness was negatively related to TDS, which is consistent with previous studies which indicated that a high salinity level is a significant threat to freshwater malacofauna, causing a loss of biodiversity and contributing to the colonisation and establishment of alien species in aquatic ecosystems.

A New AID for Interpolating and Assessing Collision Strengths and Rate Coefficients

1988 ◽  
Vol 102 ◽  
pp. 107-110
Author(s):  
A. Burgess ◽  
H.E. Mason ◽  
J.A. Tully
Keyword(s):  
Significant Loss ◽  
Impact Excitation ◽  
Rate Coefficients ◽  
Electron Impact Excitation ◽  
Graphical Display ◽  
Practical Procedure ◽  
Positive Ions ◽  
Allowed Transition ◽  
Computational Errors ◽  
Existing Data

AbstractA new way of critically assessing and compacting data for electron impact excitation of positive ions is proposed. This method allows one (i) to detect possible printing and computational errors in the published tables, (ii) to interpolate and extrapolate the existing data as a function of energy or temperature, and (iii) to simplify considerably the storage and transfer of data without significant loss of information. Theoretical or experimental collision strengths Ω(E) are scaled and then plotted as functions of the colliding electron energy, the entire range of which is conveniently mapped onto the interval (0,1). For a given transition the scaled Ω can be accurately represented - usually to within a fraction of a percent - by a 5 point least squares spline. Further details are given in (2). Similar techniques enable thermally averaged collision strengths upsilon (T) to be obtained at arbitrary temperatures in the interval 0 < T < ∞. Application of the method is possible by means of an interactive program with graphical display (2). To illustrate this practical procedure we use the program to treat Ω for the optically allowed transition 2s → 2p in ArXVI.

Effects of sterilization modes on the mechanical strengths of plaster of paris implants

1989 ◽  
Vol 47 ◽  
pp. 890-891
Author(s):  
K. Cowden ◽  
B. Giammara ◽  
T. Devine ◽  
J. Hanker
Keyword(s):  
Gamma Radiation ◽  
Calcium Sulfate ◽  
Significant Loss ◽  
Potassium Sulfate ◽  
Limiting Factors ◽  
Radiation Sterilization ◽  
Plaster Of Paris ◽  
Hardness Tester ◽  
Dry Heat ◽  
Calcium Sulfate Hemihydrate

Plaster of Paris (calcium sulfate hemihydrate, CaSO4. ½ H2O) has been used as a biomedical implant material since 1892. One of the primary limiting factors of these implants is their mechanical properties. These materials have low compressive and tensile strengths when compared to normal bone. These are important limiting factors where large biomechanical forces exist. Previous work has suggested that sterilization techniques could affect the implant’s strength. A study of plaster of Paris implant mechanical and physical properties to find optimum sterilization techniques therefore, could lead to a significant increase in their application and promise for future use as hard tissue prosthetic materials.USG Medical Grade Calcium Sulfate Hemihydrate Types A, A-1 and B, were sterilized by dry heat and by gamma radiation. Types A and B were additionally sterilized with and without the setting agent potassium sulfate (K2SO4). The plaster mixtures were then moistened with a minimum amount of water and formed into disks (.339 in. diameter x .053 in. deep) in polyethylene molds with a microspatula. After drying, the disks were fractured with a Stokes Hardness Tester. The compressive strengths of the disks were obtained directly from the hardness tester. Values for the maximum tensile strengths σo were then calculated: where (P = applied compression, D = disk diameter, and t = disk thickness). Plaster disks (types A and B) that contained no setting agent showed a significant loss in strength with either dry heat or gamma radiation sterilization. Those that contained potassium sulfate (K2SO4) did not show a significant loss in strength with either sterilization technique. In all comparisons (with and without K2SO4 and with either dry heat or gamma radiation sterilization) the type B plaster had higher compressive and tensile strengths than that of the type A plaster. The type A-1 plaster however, which is specially modified for accelerated setting, was comparable to that of type B with K2SO4 in both compressive and tensile strength (Table 1).

Bidirectional Associations Between Self-Perceptions of Aging and Processing Speed Across 3 Years

GeroPsych ◽  
2017 ◽  
Vol 30 (2) ◽  
pp. 49-59 ◽  
Author(s):  
Anna L. Seidler ◽  
Julia K. Wolff
Keyword(s):  
Processing Speed ◽  
Personal Growth ◽  
Significant Loss ◽  
Path Model ◽  
Outcome Variable ◽  
Beneficial Effects ◽  
Self Perceptions ◽  
Chi Squared ◽  
Perceptions Of Aging ◽  
Bidirectional Associations

Abstract. Background: Previous studies point to a potential relationship between self-perceptions of aging (SPA) and cognitive performance. However, most of these studies are limited by their experimental design. Previous longitudinal studies looked solely at memory as an outcome variable without examining the directionality of effects. The present study examines the direction of effects between two domains of SPA (personal growth and physical losses) and processing speed (PS). Methods: The sample consists of 8,198 participants of the German Ageing Survey (DEAS), aged between 40 and 93 years. A cross-lagged path model was estimated to examine directions of relationships across 3 years via chi-squared difference tests for each domain of SPA. Results: In the unconstrained models, the effect of SPA domain personal growth in 2008 on PS in 2011 and vice versa were marginally significant. For SPA domain physical losses, the effect of SPA on PS was significant, whereas the other direction of the effect did not reach significance. However, the cross-lagged paths of both domains of SPA on PS and vice versa could be set equal without a significant loss of model fit. The resulting associations indicate a significant bidirectional relationship between both domains of SPA and PS. Discussion and conclusion: This study provides initial evidence that SPA can influence trajectories of cognitive decline and vice versa. The results emphasize the detrimental and beneficial effects that stereotypes can have on individuals and add further evidence to the theory of stereotype embodiment.

A Collaborative Study to Establish an International Standard for Alpha-Thrombin

1992 ◽  
Vol 67 (04) ◽  
pp. 424-427 ◽  
Author(s):  
P J Gaffney ◽  
A B Heath ◽  
J W Fenton II
Keyword(s):  
Elevated Temperatures ◽  
Collaborative Study ◽  
World Health Organisation ◽  
Significant Loss ◽  
Thrombin Inhibitors ◽  
World Health ◽  
Expert Committee ◽  
International Standard ◽  
Assay Procedure ◽  
And Control

SummarySince 1975 an International Standard for Thrombin of low purity has been used. While this standard was stable and of value for calibrating thrombins of unknown potency the need for a pure a-thrombin standard arose both for accurate calibration and for precise measurement of thrombin inhibitors, notably hirudin. An international collaborative study was undertaken to establish the potency and stability of an ampouled pure a-thrombin preparation. A potency of 97.5 international units (95% confidence limits 86.5-98.5) was established for the new a-thrombin standard (89/ 588) using a clotting-assay procedure. Stability data at various elevated temperatures indicated that the standard could be transported and stored with no significant loss of potency.Ampoules of lyophilised a-thrombin (coded 89/588) have been recommended as an International Standard for a-thrombin with an assigned potency of 100 international units per ampoule by the International Society for Thrombosis and Haemostasis (Thrombin and its Inhibitors Sub-Committee) in Barcelona, Spain in July 1990 while the Expert Committee on Biological Standardisation and Control of the World Health Organisation will consider its status at its next meeting in Geneva in 1991.

Antithrombin Activity of Intact Human Platelets

1975 ◽  
Vol 34 (01) ◽  
pp. 115-126 ◽  
Author(s):  
Kiyoake Watanabe ◽  
Francis C Chao ◽  
James L Tullis
Keyword(s):  
Antithrombin Iii ◽  
Human Platelets ◽  
Significant Loss ◽  
Red Cells ◽  
Antithrombin Activity ◽  
Α2 Macroglobulin ◽  
Rapid Reaction ◽  
Pre Treatment ◽  
Different Characteristics

SummaryAntithrombin activity has been identified in intact washed human platelets. An apparent activity was demonstrated at platelet concentrations above 0.31 × 109/ml, when platelet suspensions were incubated with 2.0 NIH units/ml of thrombin. Neither red cells nor white cells revealed antithrombin activity. No significant loss of the platelet antithrombin activity was observed after ten successive washings or after treatment of platelets with antibodies to antithrombin III or α2-macroglobulin. Almost the same amount of antithrombin activity as normal platelets was demonstrated in the platelets from an afibrinogenemic patient. Pre-treatment of platelets with trypsin, papain, and neuroaminidase reduced the activity significantly, whereas lipase was without effect. The platelet antithrombin reacted with thrombin in less than 3 seconds, and this rapid reaction of platelet antithrombin was different from that of plasma antithrombin III or fibrinogen. The thrombin-like clotting activity of ancrod was inhibited by fibrinogen but not platelets. Also, unlike plasma antithrombin III or fibrinogen, brief exposure to heat (56° C or 60° C) reduced considerable amounts of platelet antithrombin activity. These results suggest that platelets possess a specific antithrombin with different characteristics from other known antithrombins.

Environmental controls on estuarine nitrifying communities along a salinity gradient

2017 ◽  
Vol 80 (2) ◽  
pp. 167-180 ◽  
Author(s):  
M Monteiro ◽  
J Séneca ◽  
L Torgo ◽  
DFR Cleary ◽  
NCM Gomes ◽  
...  
Keyword(s):  
Salinity Gradient ◽  
Environmental Controls

Fertiliser evenness - losses and costs: A study on the economic benefits of uniform applications of fertiliser

1999 ◽  
pp. 215-220 ◽  
Author(s):  
R. Horrell ◽  
A.K. Metherell ◽  
S. Ford ◽  
C. Doscher
Keyword(s):  
Crop Yields ◽  
Cumulative Effect ◽  
Economic Loss ◽  
Economic Benefits ◽  
Significant Loss ◽  
Economic Losses ◽  
Financial Return ◽  
Spread Pattern ◽  
Fertiliser Application ◽  
Seed Crops

Over two million tonnes of fertiliser are applied to New Zealand pastures and crops annually and there is an increasing desire by farmers to ensure that the best possible economic return is gained from this investment. Spreading distribution measurements undertaken by Lincoln Ventures Ltd (LVL) have identified large variations in the evenness of fertiliser application by spreading machines which could lead to a failure to achieve optimum potential in some crop yields and to significant associated economic losses. To quantify these losses, a study was undertaken to calculate the effect of uneven fertiliser application on crop yield. From LVL's spreader database, spread patterns from many machines were categorised by spread pattern type and by coefficient of variation (CV). These patterns were then used to calculate yield losses when they were combined with the response data from five representative cropping and pastoral situations. Nitrogen fertiliser on ryegrass seed crops shows significant production losses at a spread pattern CV between 30% and 40%. For P and S on pasture, the cumulative effect of uneven spreading accrues, until there is significant economic loss occurring by year 3 for both the Waikato dairy and Southland sheep and beef systems at CV values between 30% and 40%. For nitrogen on pasture, significant loss in a dairy system occurs at a CV of approximately 40% whereas for a sheep and beef system it is at a CV of 50%, where the financial return from nitrogen application has been calculated at the average gross revenue of the farming system. The conclusion of this study is that the current Spreadmark standards are a satisfactory basis for defining the evenness requirements of fertiliser applications in most circumstances. On the basis of Spreadmark testing to date, more than 50% of the national commercial spreading fleet fails to meet the standard for nitrogenous fertilisers and 40% fails to meet the standard for phosphatic fertilisers.Keywords: aerial spreading, crop response, economic loss, fertiliser, ground spreading, striping, uneven application, uneven spreading, yield loss

Survival of mouse blastocysts after low-temperature preservation under high pressure

2004 ◽  
Vol 52 (4) ◽  
pp. 479-487 ◽  
Author(s):  
Cs. Pribenszky ◽  
M. Molnár ◽  
S. Cseh ◽  
L. Solti
Keyword(s):  
Phase Transition ◽  
Hydrostatic Pressure ◽  
Low Temperature ◽  
High Hydrostatic Pressure ◽  
Room Temperature ◽  
Freezing Point ◽  
Significant Loss ◽  
Embryo Cryopreservation ◽  
Subzero Temperatures ◽  
Survival Capacity

Cryoinjuries are almost inevitable during the freezing of embryos. The present study examines the possibility of using high hydrostatic pressure to reduce substantially the freezing point of the embryo-holding solution, in order to preserve embryos at subzero temperatures, thus avoiding all the disadvantages of freezing. The pressure of 210 MPa lowers the phase transition temperature of water to -21°C. According to the results of this study, embryos can survive in high hydrostatic pressure environment at room temperature; the time embryos spend under pressure without significant loss in their survival could be lengthened by gradual decompression. Pressurisation at 0°C significantly reduced the survival capacity of the embryos; gradual decompression had no beneficial effect on survival at that stage. Based on the findings, the use of the phenomena is not applicable in this form, since pressure and low temperature together proved to be lethal to the embryos in these experiments. The application of hydrostatic pressure in embryo cryopreservation requires more detailed research, although the experience gained in this study can be applied usefully in different circumstances.

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