scholarly journals Coupled nitrogen transformation and carbon sink in the karst aquatic system: a review

2021 ◽  
Author(s):  
Wenwen Chen ◽  
Huanfang Huang ◽  
Haixiang Li ◽  
Jianhua Cao ◽  
Qiang Li ◽  
...  
Keyword(s):  
Carbon Sink ◽  
Mineral Weathering ◽  
High Rate ◽  
Karst Water ◽  
Co2 Absorption ◽  
Carbonate Mineral ◽  
System A ◽  
C Cycle ◽  
Mineralization Processes ◽  
High Concentrations

Abstract Carbonate bedrock regions represent that 14% of Earth's continental surface and carbon (C) sink in karst water plays an important role in the global C cycle due to the CO2 consumption during carbonate mineral weathering. Intensive agriculture and urbanization have led to the excessive input of nitrogen (N) into aquatic systems, while the high concentrations of inorganic C in the karst water might affect the N cycle. This paper summarized the characteristics of water in karst regions and discussed the N transformation coupled with the C cycle in the condition of high Ca2+ content, high pH, and high C/N ratios. Carbonates can consume more atmospheric and pedologic CO2 than non-carbonates because of their high solubility and high rate of dissolution, resulting in the higher average CO2 sink in karst basins worldwide than that in non-karst basins. Therefore, carbonate mineral weathering and aquatic photosynthesis are the two dominant ways of CO2 absorption, which are termed as coupled carbonate weathering. As the alkalinity and high C/N content of karst water inhibit the denitrification and mineralization processes, the karst aquatic environment is also served as the N sink.

Detection and identification of mycobacteria in the Lisbon water distribution system

2005 ◽  
Vol 52 (8) ◽  
pp. 177-180 ◽  
Author(s):  
R. Santos ◽  
F. Oliveira ◽  
J. Fernandes ◽  
S. Gonçalves ◽  
F. Macieira ◽  
...  
Keyword(s):  
Distribution System ◽  
Urban Areas ◽  
Water Distribution ◽  
Water Distribution System ◽  
Opportunistic Infections ◽  
High Rate ◽  
System A ◽  
Detection And Identification

Mycobacteria have emerged as a major cause of opportunistic infections. Until the present, only a few studies have characterized mycobacteria present in the water distribution system of urban areas. In this study, we characterize these microorganisms in the Lisbon water distribution system. Our results indicate a high rate of positivities (90.5%) with mainly saprophytic mycobacteria. Around 63% of these results belong to strains of Mycobacterium gordonae indicating a generalized proliferation of this species in the Lisbon water distribution system. A total of 21.05% of the isolates are from M. kansasii, M. intracellulare and M. chelonae.

Suppression of arousal by progesterone in fetal sheep

1997 ◽  
Vol 9 (8) ◽  
pp. 767 ◽  
Author(s):  
Kelly J. Crossley ◽  
Marcus B. Nicol ◽  
Jonathan J. Hirst ◽  
David W. Walker ◽  
Geoffrey D. Thorburn†
Keyword(s):  
Fetal Brain ◽  
Late Gestation ◽  
High Rate ◽  
Emg Activity ◽  
Fetal Sheep ◽  
Progesterone Production ◽  
Progesterone Synthesis ◽  
Ovine Fetus ◽  
High Concentrations ◽  
Vascular Catheters

The high rate of progesterone synthesis by the placenta in late gestation exposes the ovine fetus to high concentrations of progesterone and its metabolites that may affect activity of the fetal brain. The aim of this study was to determine the effect of inhibiting maternal progesterone synthesis on sleep–wake activity in fetal sheep. Fetal and maternal vascular catheters, a fetal tracheal catheter, and electrodes for recording fetal electrocortical (ECoG), electro-ocular (EOG) and nuchal muscle electromyographic (EMG) activity were implanted. At 128–131 days gestation, progesterone production was inhibited by an injection of trilostane (50 mg), a 3β-hydroxysteroid dehydrogenase inhibitor. Vehicle solution or progesterone (3 mg h -1 ) was then infused into the ewe between 6 and 12 h after the trilostane treatment. Maternal progesterone concentrations were significantly reduced from 1–24 h after trilostane treatment (P < 0·05) when followed by vehicle infusion. Fetal breathing movements (FBM), EOG, nuchal muscle EMG, and behavioural arousal increased 12 h after trilostane treatment (P < 0 · 05). In contrast, there was no change in fetal arousal, EOG, EMG or FBM activities when progesterone was infused after the trilostane treatment. These findings show that progesterone can influence fetal behaviour, and indicates that normal progesterone production tonically suppresses arousal, or wakefulness in the fetus.

scholarly journals First-Principles Design of Refractory High Entropy Alloy VMoNbTaW

Entropy ◽  
2018 ◽  
Vol 20 (12) ◽  
pp. 965 ◽  
Author(s):  
Shumin Zheng ◽  
Shaoqing Wang
Keyword(s):  
Elastic Properties ◽  
First Principles ◽  
High Entropy Alloy ◽  
Low Density ◽  
High Entropy ◽  
System A ◽  
Small Influence ◽  
High Concentrations ◽  
General Guidance ◽  
Selection Of

The elastic properties of seventy different compositions were calculated to optimize the composition of a V–Mo–Nb–Ta–W system. A new model called maximum entropy approach (MaxEnt) was adopted. The influence of each element was discussed. Molybdenum (Mo) and tungsten (W) are key elements for the maintenance of elastic properties. The V–Mo–Nb–Ta–W system has relatively high values of C44, bulk modulus (B), shear modulus (G), and Young’s modulus (E), with high concentrations of Mo + W. Element W is brittle and has high density. Thus, low-density Mo can substitute part of W. Vanadium (V) has low density and plays an important role in decreasing the brittleness of the V–Mo–Nb–Ta–W system. Niobium (Nb) and tantalum (Ta) have relatively small influence on elastic properties. Furthermore, the calculated results can be used as a general guidance for the selection of a V–Mo–Nb–Ta–W system.

scholarly journals A NOVEL APPROACH FOR DIAGNOSING LIVER LESION IMAGES IN TELEMEDICINE MODE

2012 ◽  
Vol 02 (04) ◽  
pp. 50-53
Author(s):  
Ulagamuthalvi V. ◽  
Kulanthaivel G. ◽  
Sridharan D.
Keyword(s):  
Ultrasound Image ◽  
Liver Lesion ◽  
Modern Technology ◽  
High Rate ◽  
Support Vector ◽  
Remote Location ◽  
System A ◽  
Novel Approach ◽  
Detection And Diagnosis ◽  
Diagnostic Classification System

AbstractIn this article, a novel approach for diagnosing liver lesion using ultrasound image in telemedince mode is attempted. Liver cancer is a one of the neoplastic diseases. It has a high rate of mortality. The low quality of clinical ultrasound image limits the success of early detection and diagnosis based on the images. Filtering the spcekle noise to enhance the quality and segment the ROI from the ultrasound image are carried out. Wavelet-based texture descriptors are calculated and classification has been done using support vector machine. Telemedicine is the ability to provide interactive healthcare utilizing modern technology and telecommunications. In this telemedicne mode based diagnostic classification system, a client at remote location can submit the ultrasound B-scan liver image using the Internet and after analysis in the web server, the client at remote location will receive the diagnostic result.

scholarly journals Alkaline Mineral Soil Amendment: A Climate Change ‘Stabilization Wedge’?

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2299 ◽  
Author(s):  
Fatima Haque ◽  
Yi Chiang ◽  
Rafael Santos
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Soil Amendment ◽  
Agricultural Soil ◽  
Carbon Sink ◽  
Mineral Soil ◽  
Earth Metal ◽  
Mineral Weathering ◽  
Sequestration Potential ◽  
The Impact

Extreme climate change due to heat-trapping gases, especially carbon dioxide, necessitates its mitigation. In this context, the carbon dioxide sequestration technology of enhanced weathering has for years been investigated, with a possible implementation strategy via alkaline mineral soil amendment being more recently proposed. Candidate materials for enhanced weathering include calcium and magnesium silicates, most notably those belonging to the olivine, pyroxene and serpentine groups of minerals, given their reactivity with CO2 and global availability. When these finely crushed silicate rocks are applied to the soil, the alkaline earth metal cations released during mineral weathering gradually react with carbonate anions and results in the formation of pedogenic carbonates, which, over time, and under the right conditions, can accumulate in the soil. This review paper critically reviews the available literature on alkaline mineral soil amendments and its potential to sequester enough CO2 to be considered a climate change ‘stabilization wedge’. Firstly, evidence of how agricultural soil can serve as a carbon sink in discussed, based on the observed accumulation of inorganic carbon in alkaline mineral-amended soils. Secondly, the impact of alkaline minerals on agricultural soil and crops, and the factors determining the rate of the weathering process are assessed. Lastly, the CO2 sequestration potential via alkaline mineral soil amendment is quantified according to an idealized shrinking core model, which shows that it has the potential to serve as a climate change stabilization wedge.

Gamma radioactivity on a chronosequence, Pinery Provincial Park, Ontario

1995 ◽  
Vol 75 (1) ◽  
pp. 73-84 ◽  
Author(s):  
A. J. VandenBygaart ◽  
R. Protz
Keyword(s):  
Soil Profile ◽  
Relative Concentration ◽  
Time Sequence ◽  
Mineral Weathering ◽  
Soil Processes ◽  
Carbonate Mineral ◽  
Soil Horizons ◽  
Soil Weathering ◽  
Natural Gamma ◽  
Provincial Park

Natural gamma-emitting radionuclide distributions in soils along a time sequence on dune materials in Ontario were studied. 226Ra, 232Th and 40K showed distributions influenced by soil processes and their genesis. Chronofunctions were formulated relating gamma radioisotope properties within soil horizons to the ages of the soils. 40K tended to increase in relative concentration in the upper solum as compared with the Ck likely due to carbonate mineral weathering and removal. 226Ra and 232Th tended to accumulate in the B horizons possibly associated with sorption onto Fe-oxide and clay surfaces. However, more 232Th was retained in the solum relative to 226Ra due to the immobility of 232Th. Thus the 232Th/226Ra ratio holds potential for use in studies of soil weathering. The apparent accumulation of 232Th and 226Ra within the solum during 4700 yr of soil development and weathering suggests that these radioisotopes may remain within the soil profile for long periods. Key words: Radioisotope, radionuclide, soil genesis, 40K, 226Ra, 232Th, 137Cs

scholarly journals Three Principles for Market-Based Credit Regulation

2012 ◽  
Vol 102 (3) ◽  
pp. 107-112 ◽  
Author(s):  
Perry Mehrling
Keyword(s):  
Financial Crisis ◽  
Emerging Market ◽  
High Rate ◽  
Credit System ◽  
System A

A key lesson of the financial crisis 2007-09 is that the Bagehot Rule, “lend freely but at a high rate,” needs to be updated for the emerging market-based credit system. A modern rule is suggested: Markets, not Banks; Outside spread, not Inside spread; Core, not Periphery.

Rapid turnover of organic acids in a Dystric Brunisol under a spruce–lichen forest in northern Saskatchewan, Canada

2013 ◽  
Vol 93 (3) ◽  
pp. 295-304 ◽  
Author(s):  
Kazumichi Fujii ◽  
Kokoro Morioka ◽  
Ryan Hangs ◽  
Shinya Funakawa ◽  
Takashi Kosaki ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Organic Acids ◽  
Soil Solution ◽  
Surface Soil ◽  
Microbial Respiration ◽  
Mineral Weathering ◽  
Low Molecular Weight ◽  
Rapid Turnover ◽  
C Cycle ◽  
Northern Saskatchewan

Fujii, K., Morioka, K., Hangs, R., Funakawa, S., Kosaki, and Anderson, D. W. 2013. Rapid turnover of organic acids in a Dystric Brunisol under a spruce–lichen forest in northern Saskatchewan, Canada. Can. J. Soil Sci. 93: 295–304. Organic acids released by lichen play an important role in mineral weathering and podzolization in the Boreal–Tundra transition zone of Canada; however, importance of low-molecular-weight organic acids in the soil carbon (C) cycle in the black spruce–lichen forests remains unclear. We examined soil solution composition and mineralization kinetics of 14C-radiolabelled oxalate and citrate to quantify the C fluxes from organic acid mineralization in a Dystric Brunisol under a spruce–lichen forest in northern Saskatchewan. Oxalate concentration in soil solution was greatest in the lichen layer, while the high levels of citrate were observed in the lichen and organic (O) layers to the Ae horizon with the lowest sorption capacity. Oxalate and citrate were rapidly mineralized within the lichen and O layers and had short mean residence times (0.5 to 2.7 h). Substantial C fluxes due to citrate mineralization were observed both within the lichen and O layers, but oxalate mineralization led to C flux in the lichen layer only. The contribution of citrate and oxalate to microbial respiration was large (up to 57%) in the surface soil layers. Citrate was the dominant substrate for microbial respiration of the surface soil; however, it appears that oxalate could also be an important microbial substrate within the lichen layer, at least in summer months. We conclude that the exudation of low-molecular-weight organic acids by lichenous fungi, followed by their rapid mineralization, could play an important role in the C cycles of the sandy soils under spruce–lichen forest.

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