scholarly journals Addition of Carbonaceous Material to Aquatic Sediments for Sorption of Lindane and p,p’-Dichlorodiphenyldichloroethylene

2019 ◽  
Vol 9 (9) ◽  
pp. 1722
Author(s):  
Zhiyong Guo ◽  
Tianyi Chen ◽  
Xinzhou Wang ◽  
Liwen Zhang ◽  
Liting Wang ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Sorption Isotherms ◽  
Carbonaceous Material ◽  
Minor Role ◽  
Contribution Rate ◽  
Aquatic Sediments ◽  
Factors Affecting ◽  
Leading Role ◽  
A Minor

Isomers of hexachlorocyclohexanes (HCHs) and metabolites of dichlorodiphenyltrichloroethanes (DDTs) are still frequently detected worldwide in considerable amounts, even decades after their prohibition. Carbonaceous materials (CMs) have been shown to significantly reduce risks of propagation to humans by binding the hydrophobic organochlorine pesticides (OCPs) present in aquatic sediments. In the present study, black carbons extracted from natural sediments, and artificially produced black carbons, including black carbons by burning rice straw at 450 and 850 °C, and a commercial activated carbon were compared to investigate the factors affecting the sorption of γ-HCH (lindane) and p,p’-dichlorodiphenyldichloroethylene (p,p’-DDE) on CMs. The results indicated that when the proportion of CMs to total organic carbon (ƒCM/ƒOC) was greater than 0.35, CMs played a leading role in the sorption of lindane and p,p’-DDE by the sediments. The sorption contribution rate of CMs could reach up to 64.7%. When the ratio of ƒCM/ƒOC was less than 0.10, CMs played a minor role in the sorption. In addition, the nonlinearity of the sorption isotherms was strengthened with the increasing the proportion of CMs to total organic carbon. Our findings show that ƒCM/ƒOC value is a principal parameter for assessing the sorption capacity of sediments added by CMs for OCPs.

Factors affecting bromate removal capacity of zerovalent iron packed columns

2006 ◽  
Vol 6 (6) ◽  
pp. 119-130 ◽  
Author(s):  
C. Fan ◽  
C.H. Chan ◽  
L. Xie ◽  
C. Shang
Keyword(s):  
Zerovalent Iron ◽  
Minor Role ◽  
Sulfate Concentration ◽  
Quality Factors ◽  
Bicarbonate Concentration ◽  
Factors Affecting ◽  
Weight Percentage ◽  
Removal Capacity ◽  
A Minor ◽  
Aqueous Complexes

In a series of column experiments lasting for approximately 1500 pore volume, the effects of operational factors (flow rates, sand admixtures) and water quality factors (concentrations of DO, sulfate, phosphate and bicarbonate) on bromate removal capacity of zerovalent iron were investigated. The bromate removal capacity, obtained from migration of concentration profiles, was observed to decrease with increases in flow rate. In the case that 20 wt-% iron was replaced by sands, the bromate removal capacity increased, but, on the contrary, the bromate removal capacity inevitably decreased when the weight percentage was increased by two times. Dissolved oxygen played a minor role in decreasing the bromate removal capacity, this decreasing effect only prevailed near the proximal end of depassivating irons. The bromate removal capacity increased in the presence of 100 mg/L sulfate concentration but decreased when the sulfate concentration further increased. When comparing the effect on removal capacity for phosphate and sulfate, the inhibiting effect of phosphate on the bromate removal capacity was larger. Lastly, the removal capacity increased with increasing bicarbonate concentration, which may due to the formation of aqueous complexes.

INTEREST OF THE RATIO OF INCREASE OF (β-THROMBOGLOBULIN (Δ+/βTG) AND OF FIBRINOPEPTIDE A (Δ+ FPA) FOR DIAGNOSIS AND TREATMENT OF THR0MB0-EMB0LIC DISEASES

1987 ◽  
Author(s):  
E Lavenne-Pardonge ◽  
C Col-De Beys ◽  
M Moriau
Keyword(s):  
Venous Thrombosis ◽  
Platelet Activation ◽  
Hip Prosthesis ◽  
Diagnosis And Treatment ◽  
Minor Role ◽  
Leading Role ◽  
Two Parameters ◽  
A Minor ◽  
Valvular Replacement

The interest of release of TG and FPA for the diagnosis and treatment of prethrombotic and thrombotic disorders is well knownThe ratio of increase of these two parameters (Δ+βTG/+ FPA) seems to bring some additional informations.This ratio, normally about 1, increases in isolated or preponderant platelet activation and decreases when platelet activation plays a minor role than the plasmatic factors. A more logical choice of therapeutics and a better control of its effectiveness are so possible.This study includes 91 cases of established thrombosis (20 arterial and 71 venous) and 272 cases of prethrombotic disorders (58 Raynaud syndromes, 54 cases of venous insufficiency, 60 of hip prosthesis, 40 of coronary by-pass, 60 of valvular replacement). The ratio + TG/ + FPA was calculated before, during and after efficacious or inefficacious treatment. In the cases of established thrombosis, our results confirm the leading role of platelets in the development of arterial thrombosis. The cases of venous thrombosis may be divided in two groups : simple venous thrombosis when the plasmatic factors play a leading role and complicated or recurrent venous thrombosis where the platelets play an equivalent or even a greater role.In the cases of prethrombotic states, the role of the platelets which is important on the arterial side is generally far from negligeable on the venous side. In cases of valvular replacement or of coronary by-pass the modification of the ratio lead us very frequently to modify our prophylactic therapeutics

Electrostatic and nonelectrostatic, conventional and unitary thermodynamic quantities of reaction. II. Proton–ligand and metal–ligand reactions in mixed solvents

1986 ◽  
Vol 64 (4) ◽  
pp. 785-789 ◽  
Author(s):  
Roberto Aruga
Keyword(s):  
Dielectric Constant ◽  
Mixed Solvents ◽  
Minor Role ◽  
Thermodynamic Quantities ◽  
Complex Stability ◽  
Present Treatment ◽  
Leading Role ◽  
A Minor ◽  
Metal Ligand

A calculation method of the electrostatic and the nonelectrostatic parts of thermodynamic quantities of reaction, previously proposed and applied to association reactions in aqueous medium, is applied, in the present work, to reactions in mixed solvents. The aim of the present treatment is to clarify the importance of the various factors (dependent and independent of the dielectric constant) through which the solvent affects complex stability. The method is applied to ΔG0, ΔH0, and ΔS0 data of literature for proton–ligand and metal–ligand reactions in several water–methanol, water–ethanol, and water–dioxane mixtures. The conclusions of the present study seem to confirm a leading role of solvation equilibria in determining different stabilities of complex in different solvents, while a minor role is assigned to the dielectric properties of the solvent.

scholarly journals Elemental and water-insoluble organic carbon in Svalbard snow: a synthesis of observations during 2007–2018

2021 ◽  
Vol 21 (4) ◽  
pp. 3035-3057
Author(s):  
Christian Zdanowicz ◽  
Jean-Charles Gallet ◽  
Mats P. Björkman ◽  
Catherine Larose ◽  
Thomas Schuler ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Large Scale ◽  
Meteorological Data ◽  
Snow Accumulation ◽  
Minor Role ◽  
Carbonaceous Aerosols ◽  
Svalbard Archipelago ◽  
Long Term Trends ◽  
European Arctic ◽  
A Minor

Abstract. Light-absorbing carbonaceous aerosols emitted by biomass or fossil fuel combustion can contribute to amplifying Arctic climate warming by lowering the albedo of snow. The Svalbard archipelago, being near to Europe and Russia, is particularly affected by these pollutants, and improved knowledge of their distribution in snow is needed to assess their impact. Here we present and synthesize new data obtained on Svalbard between 2007 and 2018, comprising measurements of elemental (EC) and water-insoluble organic carbon (WIOC) in snow from 37 separate sites. We used these data, combined with meteorological data and snowpack modeling, to investigate the variability of EC and WIOC deposition in Svalbard snow across latitude, longitude, elevation and time. Overall, EC concentrations (CsnowEC) ranged from <1.0 to 266.6 ng g−1, while WIOC concentrations (CsnowWIOC) ranged from <1 to 9426 ng g−1, with the highest values observed near Ny-Ålesund. Calculated snowpack loadings (LsnowEC, LsnowWIOC) on glaciers surveyed in spring 2016 were 0.1 to 2.6 mg m−2 and 2 to 173 mg m−2, respectively. The median CsnowEC and the LsnowEC on those glaciers were close to or lower than those found in earlier (2007–2009), comparable surveys. Both LsnowEC and LsnowWIOC increased with elevation and snow accumulation, with dry deposition likely playing a minor role. Estimated area-averaged snowpack loads across Svalbard were 1.1 mg EC m−2 and 38.3 mg WIOC m−2 for the 2015–2016 winter. An ∼11-year long dataset of spring surface snow measurements from the central Brøgger Peninsula was used to quantify the interannual variability of EC and WIOC deposition in snow. In most years, CsnowEC and CsnowWIOC at Ny-Ålesund (50 m a.s.l.) were 2–5 times higher than on the nearby Austre Brøggerbreen glacier (456 m a.s.l.), and the median EC/WIOC in Ny-Ålesund was 6 times higher, suggesting a possible influence of local EC emission from Ny-Ålesund. While no long-term trends between 2011 and 2018 were found, CsnowEC and CsnowWIOC showed synchronous variations at Ny-Ålesund and Austre Brøggerbreen. When compared with data from other circum-Arctic sites obtained by comparable methods, the median CsnowEC on Svalbard falls between that found in central Greenland (lowest) and those in continental sectors of European Arctic (northern Scandinavia, Russia and Siberia; highest), which is consistent with large-scale patterns of BC in snow reported by surveys based on other methods.

Bacterial decomposition of detritus in a tropical seagrass (Syringodium isoetifolium) ecosystem, measured with (Methyl- super-3H)thymidine

1993 ◽  
Vol 44 (1) ◽  
pp. 155 ◽  
Author(s):  
PC Pollard ◽  
K Kogure
Keyword(s):  
Organic Carbon ◽  
Bacterial Activity ◽  
Sediment Surface ◽  
Minor Role ◽  
Bacterial Productivity ◽  
Decomposition Of Organic Matter ◽  
Bacterial Decomposition ◽  
Algal Productivity ◽  
Syringodium Isoetifolium ◽  
A Minor

The bacterial decomposition of detritus was measured in a tropical seagrass meadow (Syringodium isoetifolium) off Dravuni Island, Fiji, and compared with the seagrass and algal productivity. Our estimates of bacterial decomposition of organic matter was based on the rate at which the bacteria divided, and this was measured by the rate at which [methyl-3H]thymidine was incorporated into the bacterial DNA. Bacterial activity was greatest in the top 1 cm of the seagrass sediments. The number of bacteria, their specific growth rate, and their productivity were 6.3 � 0.3 × 109 cells cm-3 , 0.04� 0.005 h-1, and 0.671 g C day-1 m-2 (depth-integrated over 30 cm), respectively. At the sediment surface, bacterial activity coincided with the daily light intensities during the day. Benthic microalgal production seemd to be coupled to the heterotrophic bacterial activity. However, the amount of organic carbon passing through the bacterial decomposition process was small compared with the total autotrophic production. The net bacterial productivity was only between 4 and 6% of that of microalgae and 6% of that of the seagrass. The bacteria appeared to play a minor role in the transfer of organic carbon between the primary producers and the higher trophic groups. Much of the microalgal production could have been directly consumed by the benthic infauna, whereas the seagrass production may have been translocated, via the seagrass roots and rhizomes, to other parts of the plant and/or converted into more refractory or storage compounds.

Causes and consequences of sex-biased dispersal in Columbian ground squirrel, Spermophilus columbianus

Behaviour ◽  
2006 ◽  
Vol 143 (8) ◽  
pp. 1013-1031 ◽  
Author(s):  
Peter Neuhaus
Keyword(s):  
Resource Competition ◽  
Inbreeding Avoidance ◽  
Ground Squirrels ◽  
Minor Role ◽  
Proximate Cause ◽  
Factors Affecting ◽  
Spermophilus Columbianus ◽  
Significant Difference ◽  
A Minor ◽  
Columbian Ground Squirrels

AbstractDispersal is a fundamental process with wide ranging evolutionary consequences. In birds and mammals, members of one sex typically disperse more frequently, sooner and/or further than members of the other sex. The aim of this study was to examine factors affecting dispersal by yearling male and female Columbian ground squirrels (Spermophilus columbianus), and to determine whether inbreeding avoidance, competition or other factors can explain why inter-colony dispersal is more common in males than in females. Males who stayed in their natal colony as adults emerged as yearlings heavier and later from hibernation than males who disappeared in their yearling year, whereas for females, this was not the case. Males who had sisters emerging as yearlings in the same colony were not more likely to leave the colony than males who were alone or with brothers. Further, there was no significant difference in the probability that females would mate with an immigrant compared to a natal male. Finally, three-year-old males who stayed in the colony moved significantly further away from their natal burrow than females of the same age.I conclude that sex differences in inter-colony dispersal, while promoting outbreeding, are not directly due to inbreeding avoidance, but that inbreeding avoidance may play a role in governing intra-colony dispersal distances. Further, resource competition seems to play a minor role. Aggression by adults against yearling males and the acceptance of yearling females by their mothers may be the proximate cause for male bias in inter-colony dispersal in Columbian ground squirrels. To conclusively demonstrate this effect, however, we need to look at aggression in more detail.

The Effect of Path Length and Display Size on Memory for Spatial Information

2012 ◽  
Vol 59 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Katherine Guérard ◽  
Sébastien Tremblay
Keyword(s):  
Path Length ◽  
Potential Role ◽  
Spatial Information ◽  
Recall Performance ◽  
Minor Role ◽  
Length Effect ◽  
Serial Memory ◽  
Fixed Reference ◽  
A Minor

In serial memory for spatial information, some studies showed that recall performance suffers when the distance between successive locations increases relatively to the size of the display in which they are presented (the path length effect; e.g., Parmentier et al., 2005) but not when distance is increased by enlarging the size of the display (e.g., Smyth & Scholey, 1994). In the present study, we examined the effect of varying the absolute and relative distance between to-be-remembered items on memory for spatial information. We manipulated path length using small (15″) and large (64″) screens within the same design. In two experiments, we showed that distance was disruptive mainly when it is varied relatively to a fixed reference frame, though increasing the size of the display also had a small deleterious effect on recall. The insertion of a retention interval did not influence these effects, suggesting that rehearsal plays a minor role in mediating the effects of distance on serial spatial memory. We discuss the potential role of perceptual organization in light of the pattern of results.

Use of Different Tissue Thromboplastins in the Control of Anticoagulant-Therapy

1958 ◽  
Vol 02 (05/06) ◽  
pp. 462-480 ◽  
Author(s):  
Marc Verstraete ◽  
Patricia A. Clark ◽  
Irving S. Wright
Keyword(s):  
Prothrombin Time ◽  
Anticoagulant Therapy ◽  
Factor Vii ◽  
Rabbit Brain ◽  
Minor Role ◽  
Rabbit Lung ◽  
Coagulation Mechanism ◽  
Time Test ◽  
The One ◽  
A Minor

SummaryAn analysis of the results of prothrombin time tests with different types of thromboplastins sheds some light on the problem why the administration of coumarin is difficult to standardize in different centers. Our present ideas on the subject, based on experimental data may be summarized as follows.Several factors of the clotting mechanism are influenced by coumarin derivatives. The action of some of these factors is by-passed in the 1-stage prothrombin time test. The decrease of the prothrombin and factor VII levels may be evaluated in the 1-stage prothrombin time determination (Quick-test). The prolongation of the prothrombin times are, however, predominantly due to the decrease of factor VII activity, the prothrombin content remaining around 50 per cent of normal during an adequate anticoagulant therapy. It is unlikely that this degree of depression of prothrombin is of major significance in interfering with the coagulation mechanism in the protection against thromboembolism. It may, however, play a minor role, which has yet to be evaluated quantitatively. An exact evaluation of factor VII is, therefore, important for the guidance of anticoagulant therapy and the method of choice is the one which is most sensitive to changes in factor VII concentration. The 1-stage prothrombin time test with a rabbit lung thromboplastin seems the most suitable method because rabbit brain preparations exhibit a factor VII-like activity that is not present in rabbit lung preparations.

Produktivkraft als Versprechen

2016 ◽  
Vol 46 (185) ◽  
pp. 621-638 ◽  
Author(s):  
Christian Siefkes
Keyword(s):  
Private Consumption ◽  
Minor Role ◽  
Progressive Reduction ◽  
Internal Forces ◽  
A Minor

The ‘Fragment on Machines’ from Marx’s Grundrisse is often cited as an argument that the internal forces of capitalism will lead to its doom. But the argument that the progressive reduction of labor must doom capitalism lacks a proper foundation, as a comparison with the ‘Schemes of Reproduction’ given in Capital II shows. The latter, however, aren’t fully convincing either. In reality, more depends on the private consumption of capitalists than either model recognizes. Ultimately, most can be made of the ‘Fragment on Machines’ by reading it not as an exposure of capitalism’s internal contractions, but as a discussion of a possible communist future where labor (or work) will play but a minor role.

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