Relative Stability Index Research Articles

Study on heat stress indices and their correlation with yield in Indian mustard genotypes under diverse conditions

Increasing temperatures are becoming a major challenge for agro-systems. Late mustard planting often results in overall growth reduction, poor metabolism, less productivity and yield due to heat stress at the terminal stage. A set of 45 genotypes comprising introgression lines, landraces, wild species, induced mutants, advance breeding lines and the released varieties/cultivars were evaluated under normal (Yp) and stressed environment (Ys) for yield stability during 2016-2018. The higher value of heat tolerance index, geometric mean productivity, yield stability index, relative stability index and yield production score index with lower heat susceptibility index indicated tolerance to high temperature in some genotypes. Based on the yield performance and derived traits, six genotypes namely, HLM-41-13-2 and ELM-38 with zero erucic acid quality, MCN-05-8 an induced mutant, germplasm lines PCR-3 and CSR-1163, while MCN-08-2 is released variety RB50 were rated as promising for heat stress tolerance at both the locations. Biplot analysis indicated that genotypes under group I and IV are tolerant of high yield potential and stability in a stressed environment irrespective of location.

ADAPTIVE POTENTIAL OF FENUGREEK SPECIES AT DIFFERENT SOWING TIMES

Among the unexplored technological elements of growing fenugreek in the conditions of Ukraine is the creation of conveyor cultivation of the culture. Therefore, the problem of the influence of sowing dates on the growth and development of plants, the parameters of the harvest and the qualitative composition of marketable products is acute. The purpose of this study was to substantiate the optimal sowing dates of fenugreek species to increase the yield of dried products in the conditions of Polissia on sod-podzolic soils. The leading methods employed to investigate this issue were the field method – to find the interaction of the object of research with biotic and abiotic factors, statistical method – to evaluate the research results to find the parameters of fenugreek’s adaptive capacity. During 2012-2014, for different sowing periods, the average yield of dry mass in blue fenugreek varied from 0.5 to 1.3 t/ha, and in hay fenugreek – from 0.6 to 1.5 t/ha. The early spring period and the late spring period of the 1st sowing period were characterized by the highest overall adaptive capacity. The highest value of the specific adaptive capacity was established during the late spring 2nd sowing period. The relative stability index ranged from 2.6 to 11.4. Blue fenugreek during the late spring 1st and 2nd sowing periods responds well to improved growing conditions (bi >1), and fenugreek hay during the late spring 2nd and summer sowing periods. Early spring and late spring 1st sowing period samples are characterized by high breeding value. An increase in the sum of effective temperatures by 1°C contributed to the fluctuation of green mass yield from 4.82 to 128 kg/ha, and dry mass yield from 0.401 to 6.63 kg/ha. At the same time, an increase in precipitation by 1 mm affected the fluctuation of the yield of green mass from 15.0 to 146 kg/ha, and of dry mass from 0.145 to 25.9 kg/ha. Commercial production of fenugreek species was formed within the range of the sum of air temperatures (>10°C) 383.9-487.1°C, the amount of precipitation 70.7-144.3 mm, and the growing season ranged from 35 to 55 days. The highest productivity of fenugreek species was found during sowing from the second decade of April to the first decade of May. The materials of this paper are of practical value for expanding the species diversity of vegetables and increasing the supply of the population with valuable food products and during the application of new and improved elements of technologies for growing valuable rare crops to achieve the maximum effect of fulfilling the genetic potential of plants

Stability index for the planview morphology of alluvial rivers and a case study of the Lower Yellow River

Morphological changes in river channels are influenced by flow and sediment conditions and channel boundaries, and making adjustments to the river morphology within a controllable range is vital for river engineering. Accordingly, scientific methods for efficient assessment and monitoring of river morphological changes have attracted attention from hydrologists and engineers. In this study, inspired by the Taylor series, we propose a novel quantitative metric called relative stability index of river regime (RSIRR), which solely takes geometric properties into consideration to evaluate the steady state of river channels. Corresponding coefficients of the RSIRR were determined by cluster analysis. Furthermore, we present a spatial interpolation algorithm to batch compute RSIRR values for an entire river reach over multiple years, as the extendibility of RSIRR is suitable for multiple scales from a single cross-section to a longer river reach scales. To validate the reliability of RSIRR, we applied this index to the braided reach of the Lower Yellow River (LYR) in China from Tiexie to Gaocun, thereby obtaining final thresholds to distinguish stable and unstable reaches. The spatiotemporal analysis indicates that the study area could be spatially divided into three reaches, while the obtained values of RSIRR at reach-scale expressed a decreasing trend from 1985 to 2009. Additionally, the potential of RSIRR for obtaining an early warning of unstable reaches in the study area is discussed. We conclude that RSIRR plays an important supporting role in ensuring the safety of life and property of the local people residing along a river reach.

A Novel Index (RI) to Evaluate the Relative Stability of Soils Using Ultrasonic Agitation

As soil stability is a complex phenomenon, various methods and indexes were introduced to assess the strength of soils. Because of the limitations of different stability methods and indexes (including wet sieving-based), we aimed to presents a relative stability index (RI) that was based on the estimated components of the soil overall disruptive characteristic curve (SODC): (1) soil disruption constant (Ki, that is based upon dispersion energy of soils); (2) resulting change in mean weight diameter (ΔMWD). To evaluate the effectiveness and limitations of RI as well as to compare it with classical soil stability indexes of mean weight diameter (MWD) and geometric mean diameter (GMD). Ultrasonic agitation (UA) along with a wet sieving method (followed by dry sieving) was applied against four different soils named on the basis of sample location, Qingling soil (QL), Guanzhong soil (GZ), Ansai soil (AS), and Jingbian soil (JB). To evaluate the relative strength of soils at different applied energies (increase in sonication duration usually resulted in increased input energy and temperature of soil–water suspension), soils were subjected to six sonication durations (0, 30, 60, 120, 210, and 300 s) with a fixed (and exact) initial amplitude and temperature. Output energy was calculated based on the amplitude and temperature of the suspension, vessel, and system. The most abrupt and maximum disruption of soil aggregates was observed at a dispersion energy level of 0–200 J g−1. The MWD value of surface and subsurface ranged between 0.58 to 0.15 mm and 0.37 to 0.17 mm, respectively, while GMD was ranged from 0.14 to 0.33 mm overall. The results for MWD and GMD showed a similar trend. MWD and GMD showed more strong associations with physicochemical characteristics of soil than RI. A non-significant correlation was found between RI and MWD/GMD. Contrary to MWD and GMD, RI was significantly positively correlated with sand content; this finding indicated the influential role of sand in assessing the soil’s relative strength. The results indicated that JB soil possessed the least MWD and GMD but proved to be relatively stable because of having the highest RI value.

Influence of tall fescue endophyte infection on structural stability as quantified by high energy moisture characteristic in a range of soils

Plant microbial symbionts could play a significant role on aggregate stability, an important index for soil physical quality. So far there is little information available linking the presence of endophyte in the aboveground parts of plants, with aggregate stability of rhizosphere soil. We hypothesized that the presence of Epichloë coenophiala in the aboveground parts of tall fescue (Festuca arundinacea Schreb.=Schedonorus arundinaceus and Lolium arundinaceum) may alter the structural properties of rhizospheric soil. A greenhouse pot experiment was performed to evaluate the evidence for a relationship between endophyte–tall fescue symbiosis and rhizosphere aggregate stability for a range of soils. Traditional methods for measuring aggregate stability would not be able to distinguish the impacts of these biotic factors because they usually rely on rapid immersion of aggregates in water which is very disruptive. In this study, the aggregate stability was quantified by high energy moisture characteristic (HEMC) because HEMC is capable to accurately characterize small differences in aggregate stability among the treatments and soils. Clonally propagated tillers of tall fescue (genotype 75C) naturally infected with E. coenophiala (E+) and endophyte-free ones (E−) were used. Plants were grown under optimal water, light and temperature conditions. After eight months, when plants reached the maximum vegetative growth, intact soil aggregates adherent to plant roots (i.e. rhizosphere soil) and those free of root (i.e. bulk soil) were collected for HEMC determination. The HEMCs of slow and fast wetted aggregates were determined at high matric suctions of 0 to 50hPa. HEMC data was modeled using a modified van Genuchten function. Then, various indices including volume of drainable pores (VDP), relative VDP (RVDP), VDP ratio (VDPR), modal suction (hmodal), relative hmodal (Rhmodal), stability index (SI), relative SI (RSI), stability ratio (SR), relative SR (RSR), slope at the inflection point (Si), and inflection point slope ratio (SiR) were derived to characterize soil structural stability. Endophyte presence was correlated with increased soil organic carbon (SOC) pools especially for the fine-textured soils. Changes in the SOC storage of rhizosphere soil altered the structural stability and increased the SR. The effect of endophyte infection on SR of the rhizosphere soil was also more evident in medium- and fine-textured soils due to physical protection of SOC. Lower values of hmodal and higher values of VDP of fast wetted aggregates revealed more stable macropores and greater aggregate stability in the E+ rhizosphere soil vs. E− one. VDPR, SR and SiR values of rhizosphere soil were greater in E+ plants associated soils. Fine-textured soils had lower values of SiR because of their greater values of Si in the slow wetting treatment. Plant root presence could improve the soil structure compared to the bulk soil due to exudation of cementing materials; values greater than 1 for RVDP, RSI and RSR indicate that plant root enhanced the structural stability of rhizosphere soil. In contrast to stability ratio, the effects of Epichloë endophyte–tall fescue symbiosis on relative structural stability indices such as RVDP, Rhmodal, RSI, and RSR were more pronounced in coarse- and medium-textured soils. Overall, endophyte–tall fescue symbiosis could increase aggregate stability of rhizosphere soil and thus its physical quality.

Phenotypic severity of homozygous GCK mutations causing neonatal or childhood-onset diabetes is primarily mediated through effects on protein stability.

Mutations in glucokinase (GCK) cause a spectrum of glycemic disorders. Heterozygous loss-of-function mutations cause mild fasting hyperglycemia irrespective of mutation severity due to compensation from the unaffected allele. Conversely, homozygous loss-of-function mutations cause permanent neonatal diabetes requiring lifelong insulin treatment. This study aimed to determine the relationship between in vitro mutation severity and clinical phenotype in a large international case series of patients with homozygous GCK mutations. Clinical characteristics for 30 patients with diabetes due to homozygous GCK mutations (19 unique mutations, including 16 missense) were compiled and assigned a clinical severity grade (CSG) based on birth weight and age at diagnosis. The majority (28 of 30) of subjects were diagnosed before 9 months, with the remaining two at 9 and 15 years. These are the first two cases of a homozygous GCK mutation diagnosed outside infancy. Recombinant mutant GCK proteins were analyzed for kinetic and thermostability characteristics and assigned a relative activity index (RAI) or relative stability index (RSI) value. Six of 16 missense mutations exhibited severe kinetic defects (RAI ≤ 0.01). There was no correlation between CSG and RAI (r2 = 0.05, P = 0.39), indicating that kinetics alone did not explain the phenotype. Eighty percent of the remaining mutations showed reduced thermostability, the exceptions being the two later-onset mutations which exhibited increased thermostability. Comparison of CSG with RSI detected a highly significant correlation (r2 = 0.74, P = 0.002). We report the largest case series of homozygous GCK mutations to date and demonstrate that they can cause childhood-onset diabetes, with protein instability being the major determinant of mutation severity.

Intraperitoneal stability of alginate–polyornithine microcapsules in rats: An FTIR and SEM analysis

Alginate–polycation microcapsule systems have been used over decades as delivery vehicles for cell and protein therapy. These systems have been unpredictable across a range of indications with questions resulting around the inherent stability of the alginate polysaccharide and failure mode of the delivery system. The current study focuses on such a system using 5 different alginates, 2 of which are commercially purified, which are crosslinked by polyornithine. Capsules formed by frequency-generated droplet formation were studied in the peritoneal cavity of Long-Evans rats over the course of 3 months by morphometry, Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy of the surface. Individual capsule components were also investigated on FTIR and a relative stability index was generated by titration for comparison to explanted samples over time. Using these techniques, a distinct degradation pattern was noted and is compared between the 5 alginate sources.

Mechanical stability of the in vivo lumbar spine: implications for injury and chronic low back pain

One important mechanical function of the lumbar spine is to support the upper body by transmitting compressive and shearing forces to the lower body during the performance of everyday activities. To enable the successful transmission of these forces, mechanical stability of the spinal system must be assured. The purpose of this study was to develop a method and to quantify the mechanical stability of the lumbar spine in vivo during various three-dimensional dynamic tasks. A lumbar spine model, one that is sensitive to the various ways that individuals utilize their muscles and ligaments, was used to estimate the lumbar spine stability index three times per second throughout the duration of each trial. Anatomically, this model included a rigid pelvis, ribcage, five vertebrae, 90 muscle fascicles and lumped parameter discs, ligaments and facets. The method consisted of three sub-models: a cross-bridge bond distribution-moment muscle model for estimating muscle force and stiffness from the electromyogram, a rigid link segment body model for estimating external forces and moments acting on the lumbar vertebrae, and an 18 degrees of freedom lumbar spine model for estimating moments produced by 90 muscle fascicles and lumped passive tissues. Individual muscle forces and their associated stiffness estimated from the EMG-assisted optimization algorithm, along with external forces were used for calculating the relative stability index of the lumbar spine for three subjects. It appears that there is an ample stability safety margin during tasks that demand a high muscular effort. However, lighter tasks present a potential hazard of spine buckling, especially if some reduction in passive joint stiffness is present. Several hypotheses on the mechanism of injury associated with low loads and aetiology of chronic back pain are presented in the context of lumbar spine stability.

A Novel Method for Rapid Non Destructive Determination of O/W Creams Stability

A nonconventional method for evaluation of emulsion stability was developed. The method was found to be valid for viscous emulsions and results obtained are in good correlation to conventional methods compared.The technique is based on electrical conductivity measurements during nondestructive short heating-cooling-heating cycles carried out on cosmetic viscous emulsions. Conductivity curves were obtained on a recorder, where the second heating cycles were lower and almost parallel to the first heating curves. The bigger the conductivity differences between the two heating curves, the lower is the emulsion stability.A relative Stability Index Δ/h, indicating relative change in conductivity between two cycles was elaborated. This index was usefull in finding out- optimal required HLB values for required emulsion- optimal amount of oily phase- emulsifier concentration.

A new method for stability determination of semi-solid emulsions, using conductivity measurements

A new method for rapid evaluation of emulsion stability has been developed. The technique is based on electrical conductivity measurements during non-destructive short heating—cooling—heating cycles carried out on cosmetic viscous emulsions. The conductivity curve obtained during the second heating cycle is lower and almost parallel to the first curve. The bigger the conductivity difference between the two heating curves, the lower in the stability of the emulsion. A relative stability index, Δ/h, indicating relative change in conductivity between two cycles was elaborated allowing easy comparison of emulsion stabilities having different initial conductivity. The method was compared to standard stability tests with good correlation.

Role of viscosity stratification in the stability of two-layer flow down an incline

The stability of the flow of two layers of viscous liquids down an incline is investigated. The problem is governed by two competing long-wavelength modes associated with the surfaces. One mode, calling it the first mode, is faster than the second one. When the two layers have the same coefficient of dynamic viscosity, the second mode was found earlier by the author to be the governing mode for most cases. The situation is greatly altered when viscosity is not the same for the two layers. The second mode is dramatically stabilized for the range of viscosity ratio, m, less than unity, and the first mode is now generally the governing mode in that range. The overall effect is stabilizing compared with m = 1.A relative stability index is also introduced to compare the result with that of the homogeneous case. It is found that the presence of the upper layer is generally destabilizing compared with that of a homogeneous fluid of the same total depth.