Variability Of Parameters Research Articles

Gait Biomechanical Parameters Related to Falls in the Elderly: A Systematic Review

According to the World Health Organization, one-third of elderly people aged 65 or over fall annually, and this number increases after 70. Several gait biomechanical parameters were associated with a history of falls. This study aimed to conduct a systematic review to identify and describe the gait biomechanical parameters related to falls in the elderly. MEDLINE Complete, Cochrane, Web of Science, and CINAHL Complete were searched for articles on 22 November 2023, using the following search sentence: (gait) AND (fall*) AND ((elder*) OR (old*) OR (senior*)) AND ((kinematic*) OR (kinetic*) OR (biomechanic*) OR (electromyogram*) OR (emg) OR (motion analysis*) OR (plantar pressure)). This search identified 13,988 studies. From these, 96 were selected. Gait speed, stride/step length, and double support phase are gait biomechanical parameters that differentiate fallers from non-fallers. Fallers also tended to exhibit higher variability in gait biomechanical parameters, namely the minimum foot/toe clearance variability. Although the studies were scarce, differences between fallers and non-fallers were found regarding lower limb muscular activity and joint biomechanics. Due to the scarce literature and contradictory results among studies, it is complex to draw clear conclusions for parameters related to postural stability. Minimum foot/toe clearance, step width, and knee kinematics did not differentiate fallers from non-fallers.

Disentangling Cerebellar and Parietal Contributions to Gait and Body Schema: A Repetitive Transcranial Magnetic Stimulation Study

The overlap between motor and cognitive signs resulting from posterior parietal cortex (PPC) and cerebellar lesions can mask their relative contribution in the sensorimotor integration process. This study aimed to identify distinguishing motor and cognitive features to disentangle PPC and cerebellar involvement in two sensorimotor-related functions: gait and body schema representation. Thirty healthy volunteers were enrolled and randomly assigned to PPC or cerebellar stimulation. Sham stimulation and 1 Hz-repetitive-Transcranial-Magnetic-Stimulation were delivered over P3 or cerebellum before a balance and a walking distance estimation task. Each trial was repeated with eyes open (EO) and closed (EC). Eight inertial measurement units recorded spatiotemporal and kinematic variables of gait. Instability increased in both groups after real stimulation: PPC inhibition resulted in increased instability in EC conditions, as evidenced by increased ellipse area and range of movement in medio-lateral and anterior–posterior (ROMap) directions. Cerebellar inhibition affected both EC (increased ROMap) and EO stability (greater displacement of the center of mass). Inhibitory stimulation (EC vs. EO) affected also gait spatiotemporal variability, with a high variability of ankle and knee angles plus different patterns in the two groups (cerebellar vs parietal). Lastly, PPC group overestimates distances after real stimulation (EC condition) compared to the cerebellar group. Stability, gait variability, and distance estimation parameters may be useful clinical parameters to disentangle cerebellar and PPC sensorimotor integration deficits. Clinical differential diagnosis efficiency can benefit from this methodological approach.

On the variable length scale parameter in functionally graded non-porous and porous microplate/nanoplate

In this article, the solution for free vibration and static bending of nonporous and porous square microplate/nanoplate is studied by practicing the modified couple stress theory (MCST). The impact of incorporating the length scale parameter of MCST is confirmed by comparing the results to that of molecular dynamics simulations. This study is aimed at investigating the influence of implementing a variable length scale parameter on the static and dynamic behavior of the small-scaled plates. Results are obtained adopting the analytical technique and compared to cases of presupposing constant numerical values of material length scale throughout each plate. The novelty of this theoretical study is the approach employed to achieve the formulation of the material length scale parameter, which varies along the thickness of both porous and nonporous plates. The results indicate that the inclusion of the variable length scale parameter increases the fundamental frequency and stiffness of plates. When comparing two cases of variable length scale parameter, one approximating the scale parameter of each constituent based on the bending parameter and Poisson’s ratio of the material, and the other adopting the numerical values estimated by prior experimental studies, reveals that the latter gives higher results and is chosen correspondingly.

Genetic variability parameters and character association studies among phenological traits, yield traits and quality traits under different dates of planting in chickpea (Cicer arietinum L.)

The study was conducted during rabi 2020-2021 at RARS, Nandyal, Andhra Pradesh to determine relationships among phenological traits, seed yield, yield attributes and quality traits in chickpea under different dates of planting. In the present study, in all three dates of planting, seed yield recorded highly significant and positive association with two phenological traits viz., duration of reproductive phase and duration of flowering. However, these traits were influencing seed yield via other contributing characters like days to first f lowering, duration of vegetative phase, leaf area index, days to maturity, plant height, number of branches per plant, number of pods per plant, 100 seed weight and harvest index. Strong correlations have been established between seed size and cooking time especially in kabuli and therefore, special emphasis may be given for improving the seed size with less cooking time in extra-large seeded kabuli chickpea. Further, there is sufficient genetic variability recorded for leaf area index, number of branches per plant, number of pods per plant, plant height, harvest index, seed yield, 100 seed weight, hydration capacity, swelling capacity, cooking time and iron content in the genotypes and the traits exhibited high heritability and high to moderate genetic advance in all three dates of planting.

Genetic Variability Studies of Vegetable Amaranth (Amaranthus spp.) for Productivity Traits

Aims: In the present investigation 60 different genotypes of vegetable amaranth were analysed for genetic variability in productivity traits and noticeable range of variability were reported in herbage yield and quality.
 Study Design: The layout of experimental plot was prepared according to augmented block design II (Federer, 1956).
 Place and Duration of Study: The experiment was conducted in Department of Vegetable Science, College of Horticulture, Bengaluru, UHS, Bagalkot, Karnataka during summer i.e., from January 2020 to March, 2022.
 Methodology: The experiment consisted of 60 vegetable amaranth genotypes that were collected from KRCCH, Arabhavi, NBPGR New-Delhi, TNAU, Coimbtore and some local collections, the whole plot was divided into 4 blocks, wherein, each block contained 19 beds of 1m × 1m dimension, each representing different genotypes including four check varieties. The genotypes were sown in line at the spacing of 20 cm, accommodating 10 plants per line and hence each bed accommodated 50 plants. All growth and yield parameters were recorded in five randomly selected and tagged plants of each genotype and mean was worked out for further statistical analysis. Variability parameters were worked out as per method given by Burton and Devane [1], heritability in broad sense and genetic advance as percent of mean was calculated according to the formula given Johnson et al. [2].
 Results: The phenotypic coefficient of variation and genotypic coefficient of variation was maximum for number of leaves, stem weight (g), Stem to leaf ratio, herbage yield per plant (g), herbage yield per plot (kg), leaf area per plant (cm2) and leaf size (cm2) minimum in case of plant height and stem thickness as shown in table. High heritability was observed for all the traits, except plant height and stem thickness maximum was recorded for Herbage yield per hectare (99.45 %) and minimum was observed for stem thickness (1.07%). High heritability (h2 = 99.45%) with high genetic advance (GA=92.47%) as percentage of mean was observed for herbage yield per hectare which indicated that additive gene effects were more important for that trait. High genetic advance as per cent of mean was observed for herbage yield per plant (g) however, lowest for stem thickness (0.27)
 Conclusion: Results indicates the preponderance of additive genes and selection will be effective for improvement of these traits having high heritability with genetic advance as percent of mean.

Nonlinear roll damping coefficients and natural frequency estimation via augmented extended Kalman filtering for floating body

ABSTRACT The nonlinear roll damping coefficients and natural frequency of a floating body are discussed in this article using an augmented Extended Kalman Filtering (EKF) method. This paper presents a non-linear model-based observer for the combined estimation of free roll decay motion states and damping coefficients. The identification framework uses an improved extended Kalman filter (EKF) to deal with model parameter variability and noisy measurement input. The estimated error was compared to the theoretical results obtained from the covariance matrix for filtering correctness. It is found that the nonlinear damping coefficients and natural frequency obtained from the EKF approach are a more realistic representation of the roll dynamics from the general estimation procedure given by the literature. The proposed method also has the built-in capability to remove random noise from the measured roll. The influence of noise levels in the measurements on the identification accuracy was investigated and discussed.

Stable optimisation-based scenario generation via game theoretic approach

Systematic scenario generation (SG) methods have emerged as an invaluable tool to handle uncertainty towards the efficient solution of stochastic programming (SP) problems. The quality of SG methods depends on their consistency to generate scenario sets which guarantee stability on solving SPs and lead to stochastic solutions of good quality. In this context, we delve into the optimisation-based Distribution and Moment Matching Problem (DMP) for scenario generation and propose a game theoretic approach which is formulated as a Mixed-Integer Linear Programming (MILP) model. Nash bargaining approach is employed and the terms of the objective function regarding the statistical matching of the DMP are considered as players. Results from a capacity planning case study highlight the quality of the stochastic solutions obtained using MILP DMP models for scenario generation. Furthermore, the proposed game theoretic extension of DMP enhances in-sample and out-of-sample stability with respect to the challenging problem of user-defined parameters variability.

Effect of Direct and Mediated through Maternal Organism Activation of the Catecholaminergic System on Heart Rate Parameters in Rat Fetuses.

We performed a comparative analysis of direct and mediated through the maternal organism effects of elevated catecholamine concentration on changes in the cardiac activity parameters in female rats and their fetuses on gestation days 18 and 20 under in vivo conditions. Administration of L-DOPA, a precursor of catecholaminergic transmitters, did not cause chronotropic effects in fetuses. Analysis of HR variability showed that in fetuses, irrespective of the administration route, there was an increase in nervous influences while the leading role of humoral-metabolic factors in the regulation of HR was preserved. In females receiving L-DOPA injection on day 18 of gestation, a decrease in humoral-metabolic and an increase in nerve effects were observed; in rats injected with L-DOPA on day 20 of gestation, an increase in sympathetic influences was found. Administration of L-DOPA to fetuses provoked a slight increase in the power of all components of the heart rhythm periodogram spectrum in females on day 18 of gestation and their decrease on day 20. Changes in the parameters of HR variability in females can confirm the hypothesis that in the "mother-fetus" system, the heart rhythm in the mother can be affected by both maternal and fetal influences presumably through the humoral-metabolic regulation.

Role of the Variability of Abiotic Environmental Parameters in the Population Dynamics of Invasive Ctenophores in the Black Sea

Role of the Variability of Abiotic Environmental Parameters in the Population Dynamics of Invasive Ctenophores in the Black Sea

Bumblebee pollination ensures the stability of both yield and quality of the woody oil crop Paeonia ostii ‘Fengdan’

Oil tree peony is a unique woody oil crop found exclusively in China. Its seed oil is a highly nutritious edible vegetable oil. However, its seed production varies greatly and is often low. Oil tree peony is a plant that relies on insects for pollination, but inadequate pollination is a common occurrence. In this study, we focused on the Paeonia ostii ‘Fengdan’ species and conducted a five-year study (from 2017 to 2022) in Luoyang, China. Our objective was to assess the extent of pollination deficiency and dependence, as well as quantify the contribution of supplemented bumblebees (Bombus terrestris) to the yield of oil tree peony. We also examined the effect of supplemented bumblebees on the temporal variation in yield through various pollinator survey designs, including supplemented bumblebees (BP), open pollination (OP), pollinator exclusion (EP), self-pollination treatments (SP), and artificial cross-pollination (CP). The results revealed a medium pollination deficit (D = 0.50) at the study sites for three consecutive years from 2020 to 2022, indicating limited pollination for oil tree peony under natural conditions. Importantly, BP significantly compensated for this deficiency (D = 0.22). Over the course of five years, BP increased the yield of oil tree peony by 82.87% on average compared to EP. Furthermore, the yield variation coefficient of EP (CVt=0.20) increased by 100% compared to BP (CVt=0.10). And we also observed significant variability in other yield parameters. Additionally, oil tree peony production was reduced by 44.24% in the absence of flower visitors, and the dependence on BP reached a “high” level. The fatty acid content in the seed oil did not show significant differences across treatments, indicating its stability. Overall, our pollination practices demonstrate that supplementing bee pollination can provide sufficient and stable pollination services, resulting in a higher and more stable yield of oil tree peony seeds.

Reliability Evaluation of Slopes Considering Spatial Variability of Soil Parameters Based on Efficient Surrogate Model

Reliability Evaluation of Slopes Considering Spatial Variability of Soil Parameters Based on Efficient Surrogate Model

Turbulence causes kinematic and behavioural adjustments in a flapping flier.

Turbulence is a widespread phenomenon in the natural world, but its influence on flapping fliers remains little studied. We assessed how freestream turbulence affected the kinematics, flight effort and track properties of homing pigeons (Columba livia), using the fine-scale variations in flight height as a proxy for turbulence levels. Birds showed a small increase in their wingbeat amplitude with increasing turbulence (similar to laboratory studies), but this was accompanied by a reduction in mean wingbeat frequency, such that their flapping wing speed remained the same. Mean kinematic responses to turbulence may therefore enable birds to increase their stability without a reduction in propulsive efficiency. Nonetheless, the most marked response to turbulence was an increase in the variability of wingbeat frequency and amplitude. These stroke-to-stroke changes in kinematics provide instantaneous compensation for turbulence. They will also increase flight costs. Yet pigeons only made small adjustments to their flight altitude, likely resulting in little change in exposure to strong convective turbulence. Responses to turbulence were therefore distinct from responses to wind, with the costs of high turbulence being levied through an increase in the variability of their kinematics and airspeed. This highlights the value of investigating the variability in flight parameters in free-living animals.

Accretion-induced flickering variability among symbiotic stars from space photometry with NASA TESS

Context. Symbiotic binaries exhibit a wide range of photometric variability across different timescales. These changes can be attributed to factors such as orbital motion, intrinsic variability of the individual components, or interactions between the two stars. In the range from minutes to hours, a variability induced by accretion processes that is likely to originate from the accretion disks has been detected and subsequently denoted as flickering. This variability could mimic solar-like oscillations exhibited by luminous red giants. Aims. We aim to investigate whether it is possible to utilize the precise observations of the NASA TESS mission to detect flickering in symbiotic stars, despite the fact that such studies are usually performed at shorter wavelengths than those of TESS observations. Additionally, our goal is to develop a quantitative method for the detection of accretion-induced flickering that does not rely solely on a subjective assessment of the light curves. Methods. We obtained the light curves of known symbiotic stars and a comprehensive control sample of assumed single red giants from the TESS full-frame images. To ensure consistency, all the data were processed using the same methodology, which involves filtering out the background, systematic, and long-term trends. From the processed light curves and their power spectral densities, we measured the amplitudes of the variability and other relevant parameters. Results. We introduce a method that enables a differentiation between flickering sources and stars that do not exhibit this type of variability. We detected flickering-like variability in 20 symbiotic stars utilizing TESS data, of which 13 had not previously been identified as flickering sources. Moreover, the TESS observations facilitate the detection of related variations occurring over timescales of a few days, as well as changes in the flickering behavior across multiple sectors. Conclusions. The flickering is now likely to be detected in a total of 35 known symbiotic stars. While this represents only a small subset of all symbiotic binaries, when focusing solely on accreting-only symbiotic stars where the detection of flickering is presumably more straightforward, the fraction could reach as high as ∼80%. This result suggests that accretion disks may indeed be prevalent in these binaries.

Glycemic variability in diagnosis of gestational diabetes as predictor of pharmacological treatment

IntroductionTo establish whether glycemic variability (GV) parameters used when gestational diabetes mellitus (GDM) has been diagnosed could help predict the probability that a patient will need pharmacological treatment, and to analyze the link of these parameters to the development of maternal-fetal complications. Materials and methodsA prospective study of 87 women with GDM who underwent retrospective continuous glucose monitoring (CGM) for six days between weeks 26 and 32 of gestation, following diagnosis. The mean glycemia levels and GV variables were analyzed together with their link to maternal-fetal complications, and the need for pharmacological treatment. ROC (receiver operating characteristic) curves were developed to determine validity to detect the need for pharmacological treatment. ResultsPatients with higher mean glycemia (p < 0.001) and continuous overlapping of net glycemic action in a period of n-hours (CONGAn) (p = 0.001) required pharmacological treatment. The ROC curves showed cut-off points of 98.81 mg/dL for mean glycemia, and 86.70 mg/dL for CONGAn, with 83.3% sensitivity and 67.8% specificity for both parameters. No relation between the GV parameters and development of maternal-fetal complications was observed. ConclusionsThe use of CGM, once GDM is diagnosed, enables us to identify those patients who would benefit from closer monitoring during gestation, and facilitate a speedier take-up of pharmacological treatment. However, prospective studies involving a higher number of patients are needed, as well as a cost assessment for recommending the use of CGM following GDM diagnosis.

Association Between Articular Eminence Structure and Joint Spaces in Temporomandibular Joints with Anterior Disc Displacement.

The association among the joint spaces, articular eminence morphology, and disc displacement is not well documented in the literature. This study aims to evaluate and compare the joint spaces and the articular eminence structure (eminence height [Eh] and inclination [Ei]) using cone-beam computed tomography (CBCT) of temporomandibular joints (TMJs) with anterior disc displacements and joints with normal disc position. The study groups consisted of 75 TMJs of 39 patients. The disc status of TMJs was diagnosed with magnetic resonance imaging, and the measurements were performed on CBCT. Three groups, that is, normal disc position (NDP) group, anterior disc displacement with reduction (ADDWR) group, and anterior disc displacement without reduction (ADDWoR) group, were established. Anterior, superior, posterior joint spaces (AJS, SJS, and PJS, respectively), articular Eh, and articular Ei were measured. Statistical Package for the Social Sciences version 22 was used for statistical analysis. Shapiro-Wilk test was used to check the normality of data. Intergroup comparisons of categorical variables were assessed with Fisher-Freeman-Halton test. For comparison of continuous variables parameters, Mann-Whitney U test and Kruskal-Wallis test were used. Statistical significance level was determined as P < 0.05. Significant differences were not found in intergroup comparisons for PJS. However, the difference between groups was found to be significant for AJS, SJS, Eh, and Ei. Intergroup comparisons were performed for these parameters. No significant difference was found between the NDP group and the ADDWR group for AJS, SJS, Eh, and Eİ. The mean AJS, SJS, Eh, and Ei values in ADDWoR were found to be significantly lower compared to the corresponding values in both NDP and ADDWR groups. Decreased AJS and SJS when TMJ is evaluated with CBCT may be an indicator of ADDWoR. Authors suggest that narrowed articular Ei and reduced articular Eh can be one of the predisposing factors for anterior disc displacement.

A machine learning approach to developing an accurate stratification of type 2 diabetes mellitus based on heart rate variability parameters using the k-means clustering technique in elderly women

A machine learning approach to developing an accurate stratification of type 2 diabetes mellitus based on heart rate variability parameters using the k-means clustering technique in elderly women

Estimation of Simple Correlation and Genetic Variability Studies in F2 Population of Three Different Crosses in Bhendi (Abelmoschus esculentus L. Moench)

Simple correlation analysis and variability analysis was done in three crosses of bhendi viz., IC 049972 x Arka Anamika, IC 058704 × Arka Anamika, IC 045993 × Pusa - A4 at Annamalai University, Chidambaram. The correlation analysis for eight characters plant height, days to first flowering, number of branches per plant, number of fruits per plant, fruit length, fruit girth, fruit weight, fruit yield per plant was done. The result showed that number of branches per plant, numbers of fruits per plant, fruit weight are highly correlated with fruit yield per plant. Genetic variability parameters like GCV, PCV, heritability and genetic advance as percent of mean were estimated. In all the three crosses PCV was higher in magnitude than GCV which may be due to the effect of environment. High heritability coupled with high genetic advance was observed in two crosses. This indicates the effect of additive gene action. From the above study it can be seen that fruit yield improvement in bhendi can be done by selection based on fruit weight, number of fruits per plant and number of branches per plant.

Morphometry of proximal femur in South Indian Population

Background: Proximal femur analysis plays a vital role in orthopedic surgery, implant design, fracture care, and research. Studying this complex bone helps surgeons select the right implants, plan fracture treatment, and understand bone strength. This growing field improves clinical outcomes and enhances scientific knowledge. Our study analyzes the morphometry of proximal femur, particularly the head and neck, to further explore its implications. Aims and Objectives: To study the morphometric measurements of the proximal end of the femur quantitatively in the South Indian population from the dry femora available in the Department of Anatomy, Government Medical College, Kottayam. Materials and Methods: This cross-sectional study was conducted in 101 dry femora available in the Department of Anatomy, Government Medical College, Kottayam. The measurements were taken with digital Vernier calipers and a goniometer. All continuous variables were expressed as mean with standard deviation. Statistical differences between the right and left sides were analyzed with Student’s independent sample t-test (for parametric variables) and Mann–Whitney U test (for non-parametric variables). Results: The mean vertical and anteroposterior diameter of the femoral head, superior and inferior length of the femoral head, the anteroposterior and vertical diameter of the femoral neck, superior and inferior lengths of the femoral neck, neck-shaft angle, and intertrochanteric length were 39.61±3.29 mm, 40.17±3.14 mm, 33.01±3.6 mm, 23.88±4.32 mm, 24.22±3 mm, 29.59±3 mm, 21.75±3.81 mm, 32.03±5.58 mm, 124.11±6.37, 60.31±7.33 mm, respectively. There was a statistically significant difference in the mean of neck anteroposterior diameter and neck-shaft angle between the right and left sides where the left side had the higher value. Conclusion: Notable skeletal metric variations exist amidst different populations. Proximal femoral dimensions can be acquired through either manual means or radiological information. These measurements can be used in designing orthopedic implants for the South Indian population.

Slowing gait during turning: how volition of modifying walking speed affects the gait pattern in healthy adults.

Turning during walking and volitionally modulating walking speed introduces complexity to gait and has been minimally explored. How do the spatiotemporal parameters vary between young adults walking at a normal speed and a slower speed while making 90°, 180°, and 360° turns? In a laboratory setting, the spatiotemporal parameters of 10 young adults were documented as they made turns at 90°, 180°, and 360°. A generalized linear model was utilized to determine the effect of both walking speed and turning amplitude. Young adults volitionally reducing their walking speed while turning at different turning amplitudes significantly decreased their cadence and spatial parameters while increasing their temporal parameters. In conditions of slower movement, the variability of certain spatial parameters decreased, while the variability of some temporal parameters increased. This research broadens the understanding of turning biomechanics in relation to volitionally reducing walking speed. Cadence might be a pace gait constant synchronizing the rhythmic integration of several inputs to coordinate an ordered gait pattern output. Volition might up-regulate or down-regulate this pace gait constant (i.e., cadence) which creates the feeling of modulating walking speed.

Improvement of the method of time rationing for assembling car groups on one track

Purpose. To improve the method for standardizing the duration of the shunting operation of assembling cars on one track. This can be achieved as a result of solving the following research problems: development of a method for searching the optimal order of assembling cars on one track; distribution parameters estimation of the random value of the duration of shunting operation of assembling cars on one track based on calculation experiments. Methodology. During the research, the methods of theory of railway operation, dynamic programming and mathematical statistics were used. Findings. Research on the assembling process of car group to one track established the distribution parameters of the random variable of time spent for shunting. In the course of the research, the problem of choosing the optimal order of shunting operations during car assembling was formalized and solved as a problem of dynamic programming. The time spent for shunting work was chosen as the optimality criterion. The paper considers the possibility of approximating the data of calculation experiments by analytical dependencies. It was found out that the use of linear polynomials with interaction allows obtaining dependencies describing time standards with a relative accuracy of ±5 %. Originality. The method is improved for developing the time standards for shunting work, which, unlike the existing one, is based on the performance of a series of calculation experiments, each of which solves the optimization problem of finding such an order of assembling cars that ensures minimum time consumption for shunting. Practical value. The methods developed in the work and the dependencies obtained allow improving the quality of decisions made when developing technology and designing railway stations and sidings of industrial enterprises.