scholarly journals Multiple Methods to Partition Evapotranspiration in a Maize Field

2017 ◽  
Vol 18 (1) ◽  
pp. 139-149 ◽  
Author(s):  
Youjie Wu ◽  
Taisheng Du ◽  
Risheng Ding ◽  
Ling Tong ◽  
Sien Li ◽  
...  
Keyword(s):  
Steady State ◽  
Growing Season ◽  
Chamber System ◽  
Multiple Methods ◽  
Maize Field ◽  
System Method ◽  
Flow Through ◽  
Relationship Of ◽  
Further Development ◽  
Isotopic Technique

Abstract Partitioning evapotranspiration (ET) into soil evaporation E and plant transpiration T is important, but it is still a theoretical and technical challenge. The isotopic technique is considered to be an effective method, but it is difficult to quantify the isotopic composition of transpiration δT and evaporation δE directly and continuously; few previous studies determined δT successfully under a non-steady state (NSS). Here, multiple methods were used to partition ET in a maize field and a new flow-through chamber system was refined to provide direct and continuous measurement of δT and δE. An eddy covariance and lysimeter (EC-L)-based method and two isotope-based methods [isotope combined with the Craig–Gordon model (Iso-CG) and isotope using chamber measurement (Iso-M)] were applied to partition ET. Results showed the transpiration fraction FT in Iso-CG was consistent with EC-L at both diurnal and growing season time scales, but FT calculated by Iso-M was less than Iso-CG and EC-L. The chamber system method presented here to determine δT under NSS and isotope steady state (ISS) was robust, but there could be some deviation in measuring δE. The FT varied from 52% to 91%, with a mean of 78% during the entire growing season, and it was well described by a function of LAI, with a nonlinear relationship of FT = 0.71LAI0.14. The results demonstrated the feasibility of the isotope-based chamber system to partition ET. This technique and its further development may enable field ET partitioning accurately and continuously and improve understanding of water cycling through the soil–plant–atmosphere continuum.

HUBUNGAN KEPADATAN BIVALVIA DENGAN PARAMETER LINGKUNGAN DI PESISIR TANJUNG PURA KABUPATEN BANGKA TENGAH

2020 ◽  
Vol 13 (2) ◽  
pp. 112-121
Author(s):  
Sudiyar . ◽  
Okto Supratman ◽  
Indra Ambalika Syari
Keyword(s):  
Negative Impact ◽  
Principal Component ◽  
Environmental Parameters ◽  
Data Retrieval ◽  
Distribution Patterns ◽  
Random System ◽  
System Method ◽  
Relationship Of ◽  
The Relationship ◽  
Anadara Granosa

The destructive fishing feared will give a negative impact on the survival of this organism. This study aims to analyze the density of bivalves, distribution patterns, and to analyze the relationship of bivalves with environmental parameters in Tanjung Pura village. This research was conducted in March 2019. The systematic random system method was used for collecting data of bivalves. The collecting Data retrieval divided into five research stasions. The results obtained 6 types of bivalves from 3 families and the total is 115 individuals. The highest bivalve density is 4.56 ind / m², and the lowest bivalves are located at station 2,1.56 ind / m²,  The pattern of bivalve distribution in the Coastal of Tanjung Pura Village is grouping. The results of principal component analysis (PCA) showed that Anadara granosa species was positively correlated with TSS r = 0.890, Dosinia contusa, Anomalocardia squamosa, Mererix meretrix, Placamen isabellina, and Tellinella spengleri were positively correlated with currents r = 0.933.

FORMALIZED DESCRIPTION OF THE PROCEDURE OF INFORMATION SYSTEM RISK MANAGEMENT

2018 ◽  
pp. 61-70
Author(s):  
Svetlana Sergeevna Kozunova ◽  
Alla Grigorievna Kravets
Keyword(s):  
Information System ◽  
Risk Management ◽  
Negative Consequences ◽  
Management Procedure ◽  
System Risk ◽  
Weak Points ◽  
Formalized Description ◽  
Relationship Of ◽  
The Relationship ◽  
Further Development

The article highlights the aspects of risk management in the information system. According to the analysis of the work of Russian and foreign scientists and world practices in the field of risk management, it is stated that there is a need to improve the effectiveness of risk management of information system and to develop a method for managing the risks of the information system. As a solution to the problem of effective risk management of the information system, there has been proposed a formalized procedure for managing the risks of the information system. The scientific novelty of this solution is the use of decision space and optimization space to reduce risks. This procedure allows to assess the damage, risk and effectiveness of risk management of the information system. The risks of the information system are determined and analyzed; a pyramidal risk diagram is developed. This diagram allows you to describe the relationship of risks with the components of the information system. The negative consequences to which these risks can lead are given. The analysis of methods and approaches to risk management has been carried out. Based on the results of the analysis, the methods GRAMM, CORAS, GOST R ISO / IEC scored to the maximum. The weak points of these methods and the difficulty of applying these methods in practice are described. The developed formalized risk management procedure to control the risks of information system can be used as management system’s element of the information security quality that complies with the recommendations of GOST R ISO / IEC 27003-2012. The prospect of further development of the research results is the development of management systems of risk of information system.

Conservative and nonconservative inhibitors of gastric acid secretion

1987 ◽  
Vol 253 (3) ◽  
pp. G359-G368 ◽  
Author(s):  
E. B. Ekblad ◽  
V. Licko
Keyword(s):  
Steady State ◽  
Acid Secretion ◽  
Initial Step ◽  
No Net Loss ◽  
Apparent Loss ◽  
H2 Antagonist ◽  
Flow Through ◽  
Ph Stat ◽  
High Concentrations ◽  
Continuous Presence

Inhibitors of the initial step (H2-antagonist) and of the final step (thiocyanate, SCN-; and nitrite, NO2-) were used to study the dynamics of acid secretion in isolated frog gastric mucosa. Tissues were mounted in flow-through chambers, and the acid secretion rate (SR) was recorded on a pH-stat microprocessor. Continuous presence of H2-antagonist decreases the SR to a lower steady state, and on removal the SR returns to basal SR, causing a net loss of acid, the nonconservative effect. The amount of lost acid is a unique function of exposure, thus, independent of the patterns (pulses or steps) of inhibition. In contrast, continuous presence of SCN- or NO2- (below 3 mM) results in an undershoot in SR with a return to basal SR, whereas at higher concentrations there is no return. Removal of these inhibitors causes an overshoot in SR with return to basal SR. The rebound acid is equal to acid suppressed by NO2- and low concentration of SCN-, resulting in no net loss of acid, the conservative effect, whereas at high concentrations of SCN- there is an apparent loss of acid. In maximally secreting tissue the overshoot of SR is not observed. However, the acid is not lost, merely delayed. In resting tissue NO2- also merely delays the exit of the acid produced in response to forskolin. The rebound acid is proposed to reside in a sequestered "acid" pool that is stable for at least 120 min. Results with NO2- and SCN- suggest an effect on a saturable exit enzyme, possibly the K+-H+-ATPase.

Relation of blood flow to VO2, PO2, and PCO2 in dog gastrocnemius muscle

1988 ◽  
Vol 255 (5) ◽  
pp. H1004-H1010 ◽  
Author(s):  
D. E. Mohrman ◽  
R. R. Regal
Keyword(s):  
Blood Flow ◽  
Steady State ◽  
Gastrocnemius Muscle ◽  
Muscle Blood Flow ◽  
Carbon Dioxide Tension ◽  
Experimental Conditions ◽  
Muscle Oxygen ◽  
Muscle Oxygen Consumption ◽  
Relationship Of ◽  
The Relationship

We pump-perfused gastrocnemius-plantaris muscle preparations at constant pressure to study the relationship of muscle blood flow (Q) to muscle oxygen consumption (VO2), venous oxygen tension (PVO2), and venous carbon dioxide tension (PVCO2) during steady-state exercise at different rates. Tests were performed under four experimental conditions produced by altering the perfusate blood-gas status with a membrane lung. The consistency of the relationship of Q to other variables was evaluated by statistical analysis of fitted curves. Not one of the above listed variables had the same relationship with Q in all four of the experimental conditions we tested. However, we did find that a consistent relationship existed among Q, PVO2, and PVCO2 in our data. That relationship is well described by the equation (Q-23).[PVO2 - (0.5.PVCO2) - 3] = 105 (when Q is expressed in ml.100 g-1.min-1 and PVO2 and PVCO2 in mmHg). One interpretation of this result is that both PO2 and PCO2 are important variables in the control of blood flow in skeletal muscle the combined influence of which could account for nearly all of the hyperemia response to steady-state muscle exercise.

scholarly journals Nitrogen Biogeochemistry in Lakes – Chemical and Biological Drivers and Developing Techniques to Explicitly Measure Concurrent Processes

2021 ◽  
Author(s):  
Yat-Fung (Jeremy) Lau
Keyword(s):  
Nitrogen Cycling ◽  
Community Composition ◽  
Nutrient Loading ◽  
Chamber System ◽  
Benthic Chamber ◽  
Concurrent Processes ◽  
Flow Through

A benthic chamber system was developed to measure all major nitrogen cycling processes in lakes. The system coupled advantages of flow-through systems common in core incubations with those of Nutrient loading ratios (Si:N and P:N) and community composition of herbivores (

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