Use of the evaporative method for determination of soilless substrate moisture characteristic curves

2016 ◽  
Vol 211 ◽  
pp. 102-109 ◽  
Author(s):  
Jeb S. Fields ◽  
James S. Owen ◽  
Lin Zhang ◽  
William C. Fonteno
Keyword(s):  
Characteristic Curves ◽  
Moisture Characteristic ◽  
Substrate Moisture ◽  
Soilless Substrate

scholarly journals Integrating Moisture Characteristic Curves with Gravimetric Data in the Management of Substrate Moisture Content for Annual Vinca

HortScience ◽  
2018 ◽  
Vol 53 (8) ◽  
pp. 1197-1202
Author(s):  
Adam F. Newby ◽  
James E. Altland ◽  
Daniel K. Struve ◽  
Claudio C. Pasian ◽  
Peter P. Ling ◽  
...  
Keyword(s):  
Moisture Content ◽  
Water Content ◽  
Leaf Area ◽  
Dry Weight ◽  
Sphagnum Moss ◽  
Matric Potential ◽  
Characteristic Curves ◽  
Root Dry Weight ◽  
Moisture Characteristic ◽  
Substrate Moisture

Greenhouse growers must use water more efficiently. One way to achieve this goal is to monitor substrate moisture content to decrease leaching. A systems approach to irrigation management would include knowledge of substrate matric potentials and air-filled pore space (AS) in addition to substrate moisture content. To study the relationship between substrate moisture and plant growth, annual vinca (Catharanthus roseus L.) was subject to a 2 × 2 factorial combination of two irrigation treatments and two substrates with differing moisture characteristic curves (MCCs). A gravimetric on-demand irrigation system was used to return substrate moisture content to matric potentials of −2 or −10 kPa at each irrigation via injected drippers inserted into each container. Moisture characteristic curves were used to determine gravimetric water content (GWC), volumetric water content (VWC), and AS at target substrate matric potential values for a potting mix consisting of sphagnum moss and perlite and a potting mix consisting of sphagnum moss, pine bark, perlite, and vermiculite. At each irrigation event, irrigation automatically shut off when the substrate-specific weight of the potted plants associated with the target matric potential was reached. Irrigation was triggered when the associated weight for a given treatment dropped 10% from the target weight. VWC and AS differed between substrates at similar matric potential values. Irrigating substrates to −2 kPa increased the irrigation volume applied, evapotranspiration, plant size, leaf area, shoot and root dry weight, and flower number per plant relative to irrigating to −10 kPa. Fafard 3B had less AS than Sunshine LB2 at target matric potential values. Plants grown in Fafard 3B had greater leaf area, shoot dry weight, and root dry weight. Leachate fraction ranged from 0.05 to 0.08 and was similar across all treatment combinations. Using data from an MCC in conjunction with gravimetric monitoring of the container–substrate–plant system allowed AS to be determined in real time based on the current weight of the substrate. Closely managing substrate matric potential and AS in addition to substrate water content can reduce irrigation and leachate volume while maintaining plant quality and reducing the environmental impacts of greenhouse crop production.

scholarly journals Characteristic Curves and Criterion of Critical Difference in Assessing the Informativeness of Markers of Renal Damage in Lithotripsy

2021 ◽  
Vol 9 (4) ◽  
pp. 593-597
Author(s):  
R. S. Iskhakova ◽  
A. G. Gilmanov
Keyword(s):  
Renal Injury ◽  
Control Group ◽  
Diagnostic Efficiency ◽  
Critical Difference ◽  
Diagnostic Significance ◽  
Diagnostic Efficacy ◽  
Characteristic Curves ◽  
Injury Characteristic ◽  
First Session

Aim of study. Determination of the diagnostic significance of laboratory biomarkers of renal tissue damage in remote nephrolithotripsy in patients with urolithiasis.Material and methods. On the basis of the urology department of the Republican Clinical Hospital (Ufa), 35 patients with urolithiasis were examined, who underwent remote shock wave lithotripsy sessions. The laboratory parameters were determined in patients: the number of erythrocytes, leukocytes in the blood, the level of lipocalin and microalbumin in the urine, as well as alpha2-microglobulin and cystatin C in the blood serum. The control group included 14 healthy donors. To determine the diagnostic efficacy of biomarkers of renal injury, characteristic curves were plotted, and lipocalin level shifts were interpreted taking into account the data on the critical difference criterion value.Results. When studying the urinary level of lipocalin in patients with urolithiasis, it was found that the difference in the concentration of the biomarker in them and in healthy individuals is statistically insignificant (0.68 pg/ml versus 0.4 pg/ml). After the first session of extracorporeal lithotripsy, an increase in urinary excretion of lipocalin by 5 times is noted, after the second - by an additional 1.6 times, and after the third - by another 1.7 times (the differences are statistically significant). To analyze the prognostic efficiency of markers of renal injury, characteristic curves were plotted. The area under the ROC curve for lipocalin varied from 0.77 to 0.80 depending on the number of sessions, which indicates a high diagnostic efficiency of this biomarker. The determination of the criterion of critical difference (CCD) showed that an increase in the level of lipocalin in the urine after the first session of lithotripsy more than 2.1 times is statistically significant. The concentration of the specified biomarker in urine exceeding 4.5 pg/ml, 6 pg/ml and 10 pg/ml after the first, second and third sessions of lithotripsy, respectively, can be considered as a basis for changing treatment tactics (delaying the second procedure) or performing lithotripsy in another way.Conclusion. Urinary lipocalin, associated with neutrophil gelatinase, is an informative biomarker of renal injury in the assessment of complications associated with the lithotripsy procedure.

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