Pushing Resistance Research Articles

Comparative analysis of two strength training protocols on throwing speed in women's handball

Shooting represents a fundamental skill in handball. Among other factors, its effectiveness requires a significant development of explosive strength. Isometric training may provide a powerful neuromuscular stimulus for its enhancement. Despite its importance and practicality, few studies have addressed the effect of this type of training on shooting speed in women's handball. Twenty female players were divided into two groups: isometric training (GI, n=10) and dynamic training (GD, n=10). Over nine weeks, twice a week, both groups completed an upper limb pushing resistance training: GI performed maximum isometric strength, and GD performed dynamic strength at 80% of one maximum repetition (1MR). In both cases, the effort was followed by medicine ball throws. The loads for both groups were equated in terms of sets and duration. Pre- and post-intervention, the 1MR of each player was estimated through a load progression test in bench press exercise. Additionally, the shooting speed with and without aiming at a target was measured from seven and nine meters using a radar. The findings showed a trend towards improvement in both groups (slightly higher in GI); however, only the not-targeted shooting speed from 9 meters in GI reached statistical significance (p < .05). The correlation between 1MR and shooting speed was low to moderate. In summary, both types of training yielded similar results. Given the practical advantages of isometric training, it could be suggested that this training could serve as an effective and practical alternative for enhancing strength and shooting speed in handball. Keywords: Handball, handball shooting, isometric strength training, women's sport.

Impacts of ozone stress on stem lodging characteristics of different indica and japonica rice cultivars

AbstractOzone (O3) stress inhibits rice growth and development, resulting in yield loss and poor quality. However, the effect of ozone stress on the lodging resistance of rice stems has scarcely been reported. In this study, three indica rice cultivars and three modern japonica rice cultivars were treated with high O3 concentration (100 ppb) while a gas fumigation platform was used in the indoor control (about 10 ppb). The influence of O3 stress on lodging resistance was investigated in 2016 and 2017. Ozone stress reduced the in situ pushing resistance of intact plants by 40% and single stems by 32.0%. The breaking resistance of the third, fourth, and fifth internodes from the top of the rice stem was, respectively, reduced by 24.0%, 25.1%, and 33.6%, on average. The O3‐induced reduction in the basal internode morphological characteristics was associated with the reduced cross‐sectional area, maximum and minimum stem diameter, dry weight per unit length, length, dry weight, and culm wall thickness. Among these characteristics, the largest reduction was exhibited by internode dry weight (−43.1%), while the lowest reduction was observed for culm wall thickness (−9.7%). The O3 induced a significantly higher reduction in basal internode characteristics of indica compared with the japonica rice, with a larger effect in the lower internode than the upper internode, indicating a significant interaction between O3 and rice cultivar and internode position. Statistical analysis revealed a significant positive linear correlation between the response of in situ pushing resistance of rice under O3 stress and the response of basal internode breaking resistance, cross‐sectional area, and dry weight per unit length. Ozone stress significantly reduced the lodging resistance in the rice stem, which is primarily associated with the thinning and poor filling of the basal internodes, and the O3 impacts varied with cultivars and internode positions, but were similar between the two years. These results provide a scientific reference for the study of lodging resistance regulation of rice under high O3 concentrations.

Physicochemical characteristics of lodging susceptibility of rice cultivars in response to ozone exposure

High tropospheric ozone concentrations reduce rice yield and grain quality, which imposes a serious threat to food security in Asia. This study aimed at determining the effect of ozone on rice lodging, an unpredictable constraint for achieving high yield and good quality in rice production under climate change. Two rice cultivars with different ozone sensitivity were exposed to ozone concentration of 80 ppb (8 h per day) and control conditions (13 ppb) in natural-light fumigation chambers from tillering to maturity. The pushing resistance of intact plants and the lodging-related culm traits were examined. Ozone exposure significantly decreased the in-situ pushing resistance of intact plant or single culm in the ozone-sensitive cultivar YD6, but had no effects in the ozone-tolerant cultivar WYJ27. Ozone reduced breaking resistance and bending moment to a similar magnitude, resulting in no change of lodging index when averaged across all rice basal internodes. In general, WYJ27 was less responsive to ozone than YD6. Negative ozone effects on lodging-related culm traits of YD6 included reductions in the internode dry weight as well as the dry weight per unit internode length, decreases in internode diameter, cross section area and culm wall thickness of basal internodes, and reduced concentrations of soluble sugar and starch. Correlation analysis indicated that ozone-induced decrease in culm strength of YD6 was mainly attributed to the thinner internodes and the smaller culm density due to less nonstructural carbohydrate deposition. The ozone-sensitivity of YD6 was confirmed by its high yield reduction of 25 %, caused by an 11 % decrease in spikelet number per panicle and a 10 % decrease in fulfilled grain weight. The results suggested that rice ozone sensitivity in yield was in consistent with that in stem strength, which could result in no change of lodging index under greenhouse conditions. The realistic lodging susceptibility of these cultivars in response to ozone pollution in open paddy fields, where rice was often subjected to wind and rain during ripening stage, needs further investigation.

Deep fertilization combined with straw incorporation improved rice lodging resistance and soil properties of paddy fields

Deep nitrogen fertilization (DNF) coupled with straw incorporation has the potential to improve the grain yield and nitrogen use efficiency of mechanically transplanted rice. However, the effects of different fertilization approaches combined with straw incorporation on lodging resistance ability, and soil properties are still uncertain. Therefore, a two-year field experiment was comprised of broadcast fertilizer treatments (broadcast fertilizer without straw (BFS0) or with straw (BFS)), deep fertilizer treatments (DNF without straw (DFS0) or with straw (DFS)). Results depicted that deep fertilizer treatments significantly improved the pushing resistance force by 63.81–129.58 % and decreased the lodging index by 22.01–80.82 % of rice compared with broadcast fertilizer treatments. Deep fertilizer treatments optimized the length of the first four internodes and increased the internodes diameter and culms wall thickness in the third and fourth internode, and higher silicon and lignin content in the fourth internode, compared to broadcast fertilizer treatments. Furthermore, the straw incorporation treatments also improved soil total nitrogen, soil available potassium, and soil organic matter by 5.60–11.48 %, 17.75–22.56 %, and 7.17–18.26 %, respectively, regardless of fertilizer application method. Hence, this study suggests that deep nitrogen fertilization can be adopted as an agronomically effective tactic to improve lodging resistance in rice whilst the combination of straw incorporation and deep fertilization can be considered to further improve the soil properties.

Novel Endovascular Interventional Surgical Robotic System Based on Biomimetic Manipulation

Endovascular therapy has emerged as a crucial therapeutic method for treating vascular diseases. Endovascular surgical robots have been used to enhance endovascular therapy. However, to date, there are no universal endovascular surgical robots that support molds of different types of devices for treating vascular diseases. We developed a novel endovascular surgical robotic system that can independently navigate the intravascular region, advance and retract devices, and deploy stents. This robot has four features: (1) The bionic design of the robot can fully simulate the entire grasping process; (2) the V-shaped relay gripper waived the need to redesign special guidewires and catheters for continuous rotation; (3) the handles designed based on the feedback mechanism can simulate push resistance and reduce iatrogenic damage; and (4) the detachable design of the grippers can reduce cross-infection risk and medical costs. We verified its performance by demonstrating six different types of endovascular surgeries. Early evaluation of the novel endovascular robotic system demonstrated its practicability and safety in endovascular surgeries.

Unveiling the genetic architecture for lodging resistance in rice (Oryza sativa. L) by genome-wide association analyses.

Lodging is one of the major abiotic stresses, affecting the total crop yield and quality. The improved lodging resistance and its component traits potentially reduce the yield losses. The section modulus (SM), bending moment at breaking (M), pushing resistance (PR), and coefficient of lodging resistance (cLr) are the key elements to estimate the lodging resistance. Understanding the genetic architecture of lodging resistance–related traits will help to improve the culm strength and overall yield potential. In this study, a natural population of 795 globally diverse genotypes was further divided into two (indica and japonica) subpopulations and was used to evaluate the lodging resistance and culm strength–related traits. Significant diversity was observed among the studied traits. We carried out the genome-wide association evaluation of four lodging resistance traits with 3.3 million deep resolution single-nucleotide polymorphic (SNP) markers. The general linear model (GLM) and compressed mixed linear model (MLM) were used for the whole population and two subpopulation genome-wide association studies (GWAS), and a 1000-time permutation test was performed to remove the false positives. A total of 375 nonredundant QTLs were observed for four culm strength traits on 12 chromosomes of the rice genome. Then, 33 pleiotropic loci governing more than one trait were mined. A total of 4031 annotated genes were detected within the candidate genomic region of 33 pleiotropic loci. The functional annotations and metabolic pathway enrichment analysis showed cellular localization and transmembrane transport as the top gene ontological terms. The in silico and in vitro expression analyses were conducted to validate the three candidate genes in a pleiotropic QTL on chromosome 7. It validated OsFBA2 as a candidate gene to contribute to lodging resistance in rice. The haplotype analysis for the candidate gene revealed a significant functional variation in the promoter region. Validation and introgression of alleles that are beneficial to induce culm strength may be used in rice breeding for lodging resistance.

Experimental and nonlinear finite-element analysis study on lateral push resistance of San-dou components perpendicular and parallel to grain in traditional timber buildings

Dou-gong is an essential part of traditional timber buildings in East Asia, having a decoration function and a load transfer function. The San-dou component, which is vulnerable to the lateral push force of the Gong, Fang, and purlin, is a critical structural component in the Dou-gong. In San-dou components, there are two distinctive types of surfaces subjected to lateral push force, perpendicular to the grain and parallel to the grain. However, few investigation into the structural performance of these two types has been done. Considering this shortcoming in the literature, in the current study, tests were carried out to obtain elasticity and strength characteristics on 90 timber specimens of fir and larch. After the material property test, 24 San-dou specimens were prepared to investigate the lateral push resistance. Consequently, an elastic–plastic damage assessment model was developed to calculate the load–displacement curve and possible damage distribution region of San-dou component, using the nonlinear finite-element analysis. According to the analyses, the failure mode for the San-dou component perpendicular to the grain is a horizontal crack parallel to the Dou-ear. Besides, the failure mode of the San-dou component parallel to the grain is an oblique crack, which begins from the inner edge of the Dou-ear to the lower part of the San-dou component. In the case of the other factors being the same, the bearing capacity of the larch San-dou component is 49.64–55.78% stronger than the fir San-dou component. Besides that, the bearing capacity of the San-dou component perpendicular to the grain is 32.85–38.22% higher than the San-dou component parallel to the grain. The research findings are expected to give a theoretical foundation for the structural evaluation of the Dou-gong system in traditional timber buildings and a scientific basis for elucidating the differences in the construction of traditional timber buildings in East Asia.

Novel QTL for lodging resistance, PRL4, improves physical properties with high non-structural carbohydrate accumulation of basal culms in rice (Oryza sativa L.)

Resistance to lodging, an important problem in rice production, has three types: low plant height, strong culm, and high strength of the lower part of the plant. The determinants of strength of the lower part remains unclear, compared with plant height and culm strength. This study identified a new genetic factor involved in the strength of the lower part, as assessed by pushing resistance, using chromosomal segment substitution lines (CSSLs) to clarify the determinants of strength of the lower part by functional analysis of the CSSL and the introgression line (IL) harboring the identified quantitative trait locus (QTL). QTL analysis identified the QTL for increasing pushing resistance on chromosome 4, PRL4, which was not related to days to heading. The CSSL with PRL4 showed increased pushing resistance and physical strength of the basal culm, but decreased filled grain ratio and grain weight. The IL with PRL4, developed by backcrossing this CSSL, improved pushing resistance and the strain of culm until breaking under compression, and did not decrease yield traits. These lines with PRL4 increased the accumulation of non-structural carbohydrate (NSC) in the basal culm at the fully ripe stage. Thus, the genetic control of NSC accumulation in culms by PRL4 may improve the strength of the lower part by enhancing culm toughness with strength and ductility.

Influence of geometric parameters on partial compressive force and pushing performance of flow diverter

Research on flow diverter (FD) has progressed over the past decades; however, the relationships between parameters such as stent diameter, porosity, and number of wires and the properties of FDs, such as partial compressive force and push resistance, are not well understood. In this study, the partial compressive force and push resistance of braided FDs with varying porosity (61%-75%), diameter (2.5-5.0 mm), and number of wires (48 or 64) were evaluated using finite element analysis (FEA) and bench tests. At a small compression ratio, the 48-wire stents exhibited a larger partial compressive force than 64-wire stents of the same diameter. But when the compression ratio was 50%, the 64-wire stents had better resistance to pressure. The partial compressive force decreased as the stent diameter increased when all other parameters were equal. However, the influence of the diameter decreased as the stent porosity increased. The push resistance decreased as the porosity and diameter increased, and increased with the number of wires. These results provide useful information for FD design. Decreasing the number of wires can reduce the push resistance, while the push resistance is mainly influenced by the porosity and number of wires, and almost has no relationship with the partial compressive force. The FEA model proved very reliable, and corresponded well to the bench test results, which indicates that this model can be utilized to guide the design of FDs.

Genome-wide association study to identify soybean stem pushing resistance and lodging resistance loci

Lodging resistance is an important objective for soybean [Glycine max (L.) Merr.] breeding, but selection for this trait has been difficult since the resistance is controlled by multiple genes, and these genes interact with the environment. A total of 130 of 139 lines constituting a soybean genome-wide association study panel were phenotyped for stem pushing resistance, which is defined as the push-back strength when the plant stem is inclined, by measuring the force required to push a stem to a 45° angle using a force gauge in a greenhouse, and also for lodging, plant height, seed yield, and maturity at three locations in total in eastern Canada in 2013 or 2017. Two quantitative trait loci (QTLs) for pushing resistance were identified on chromosome 5 and 11, and each QTL accounted for 16.0% of phenotypic variation. In our panel, the alleles for higher pushing resistance were always of lower frequency than the alternate allele. Examining the panel at these QTLs identified that higher pushing resistance was associated with lower lodging on chromosomes 5 and 11, and that the difference for lodging between alleles was significant on chromosome 5. There was no difference in plant height or yield at the QTL on chromosomes 5 or 11, while higher pushing resistance was associated with later maturity at both QTLs. The pushing resistance QTL on chromosome 11 will be useful for decreasing lodging in Canadian short-season soybean.

Biomechanical Properties and Agro-Morphological Traits for Improved Lodging Resistance in Ethiopian Teff (Eragrostis tef (Zucc.) Trottor) Accessions

Susceptibility to lodging is a major constraint on teff production in Ethiopia, but efforts to develop lodging-resistant cultivars have not been successful. We studied the mechanical properties of teff culms and associated agro-morphological traits in field experiments with 320 teff accessions at two sites in northwestern Ethiopia during the 2018 and 2019 growing seasons. The results showed significant variability in both mechanical properties and agro-morphological traits among accessions. Traits contributing to lodging resistance, such as internode diameter, pushing resistance, and base failure moment, were significantly positively correlated with each other and with plant height. Similarly, the correlation of those traits with lodging index was significant and positive. In contrast, tiller number showed a significant negative correlation with lodging index. The peduncle–panicle length, which generally accounted for 59% of the plant height, should be a target when breeding for semi-dwarfism. Root system development, which reached a depth of more than 1 m in tall and 57 cm in dwarf teff accessions, signifies the presence of genetic variabilities for future root lodging studies in teff, and it may also explain why teff performs well in drought-prone areas of Ethiopia. Breeding programs for lodging resistance might focus on accessions with good standing ability (high base failure moment) and introgression of stem strength with a semi-dwarf phenotype. Alternatively, selection for a large internode diameter, increased pushing resistance and base failure moment, and a reduced tiller number should be considered.

Numerical study of the stopping distance for runaway vehicle on truck escape ramp by using the improved equation of car driving

The stopping distance of the runaway vehicle on the mountain road directly affects the length design of the arrester bed. Since the subsidence depth of runaway vehicle wheel on the arrester bed is neglected in the past researches, the stopping distance estimated by the vehicle driving equation is not accurate. The purpose of this paper is to supplement the influence of subsidence depth on rolling resistance and the influence of mountain highway altitude on air resistance, and improve the estimation accuracy through improved vehicle driving equation. Firstly, the formula for fitting the subsidence depth is established, and the formula for calculating the pushing resistance and compaction resistance is added. Considering the influence of the altitude of the mountain road on the air resistance, the formula for calculating the corrected air resistance and the air lift is added too and the improved vehicle driving equation is generated. Secondly, a simulink model is established based on the improved vehicle driving equation and determine the attester bed entering position and the initial entering speed of the runaway vehicle. Finally, the simulation model is run and analysed. The results show that the error rate of the simulation results is less than 8.0% compared with the full-scale test data. Compared with original equation, the shortening rate of the stopping distance is up to 85.59%.

Morphological Traits Associated with the Quantitative Trait Locus for Lodging Tolerance in Soybean

Lodging tolerance is an important trait of soybean [Glycine max (L.) Merr.] that affects yield stability and combine‐harvesting efficiency. Previously, a quantitative trait locus analysis of lodging scores was performed using recombinant inbred lines developed by crossing the lodging‐susceptible cultivar Toyomusume with the lodging‐tolerant cultivar Toyoharuka, and the major quantitative trait locus qLS19‐1 was identified. However, the morphological traits associated with qLS19‐1 remain unclear. To develop high‐precision DNA markers for qLS19‐1, it is necessary to identify its associated lodging tolerance‐related traits. Here, we studied the effects of qLS19‐1 on lodging‐related traits, primarily pushing resistance, using the Toyomusume‐backcrossed line and near isogenic lines (NILs). The Toyoharuka allele at qLS19‐1 may increase the number of primary lateral roots and cause a high pushing resistance, resulting in a lower ratio of the pushing resistance moment. The negative correlation between the number of primary lateral roots and the lodging scores in 2 yr suggests that this trait's influence on lodging score is stable. The numbers of primary lateral roots of six recombinant NILs were evaluated for the fine mapping of qLS19‐1. Sat_099 and BARCSOYSSR_19_1255 were the molecular markers that correlated with changes in the number of primary lateral roots among the recombinant NILs. We believe that the gene responsible for controlling primary lateral root number is located within the associated 356‐kb region. Thus, the investigation of the number of primary lateral roots and/or the marker‐assisted selection for qLS19‐1 may improve lodging tolerance in breeding programs.

Elevated CO2 improves lodging resistance of rice by changing physicochemical properties of the basal internodes

Elevated atmospheric CO2 concentration has been shown to increase rice yield but its effect on plant lodging resistance is still under debate. In this study, we examined lodging incidence in the field and lodging-related traits of two rice cultivars with contrasting lodging susceptibility under ambient and elevated CO2 (ca. 200 μmol mol−1 above ambient) concentrations by using a free-air CO2 enrichment (FACE) system. Elevated CO2 (E-CO2) increased lodging resistance as shown by reduced visual lodging incidence in the field at the late grain filling stage in E-CO2 plots. This coincided with enhanced in situ pushing resistance of intact plants one week before lodging occurred. The positive CO2 effect was more pronounced in the lodging-susceptible cultivar LY084. In contrast, the cultivar WYJ23 displayed greater pushing resistance in the field, and no lodging occurred at either ambient or elevated CO2 conditions throughout the cropping season. The field observations were consistent with the physicochemical characterization of basal internodes of rice plants at the grain filling stage. Greater lodging-resistance of WYJ23 was mainly attributed to its shorter plant height and thicker culm wall of basal internodes. The improvement of lodging resistance by E-CO2 for the lodging-susceptible cultivar LY084 was mainly related to enhanced culm density, which was explained by elevated starch deposition in the stem. Less lodging incidence under elevated CO2 contributed to an increase in grain yield by 36% for LY084. In conclusion, rice production could benefit from elevated CO2 in a changing climate because of an increase in lodging resistance as a result of CO2-induced improvements in mechanical strength of basal internodes.

Study on the vibration characteristics of coke pushing ram in the coke pushing process

Serious vibrations can occur in the coke pushing ram in the coke pushing process and may directly affect the regular production of coke oven, in order to avoid vibration, it is necessary to study the vibration characteristics of coke pushing ram. In this article, the coke pushing resistance is derived via the coke pushing current and a mathematical model of coke pushing ram in the coke pushing process is established to study the vibration mechanism of coke pushing ram. The results indicate that in the low-velocity and heavy-load coke pushing process after the slipper enters the carbonization chamber, the coke pushing velocity is less than the critical velocity, which indicates that the stick-slip vibration occurs in the coke pushing ram, and the factors affecting the coke pushing ram stability mainly include the difference between the static and dynamic friction coefficients, stiffness, and damping. The results are validated by numerical simulation and experiment test.

Turning traction force of tracked mining vehicle based on rheological property of deep-sea sediment

Abstract Based on main physical and mechanical properties of deep-sea sediment from C-C poly-metallic nodule mining area in the Pacific Ocean, the best sediment simulant was successfully prepared by mixing bentonite with a certain content of water. Compression–shear coupling rheological constitutive model of the sediment simulant was established by endochronic theory and the coupling rheological parameters were obtained by compressive and compression–shear creep tests. A new calculation formula of turning traction force of the tracked mining vehicle was first derived based on the coupling rheological model and consideration of pushing resistance and sinkage of the tracked mining vehicle. Effects of the turning velocity, crawler spacing and contacting length of crawler with deep-sea sediment on the turning traction force were analyzed. Research results can provide theoretical foundation for operation safety and optimal design of the tracked mining vehicle.

ダイズ品種「トヨハルカ」の耐倒伏性に関与する形質の同定 : 押倒し抵抗とその関連形質におけるトヨハルカとトヨムスメおよび耐倒伏性QTLの準同質遺伝子系統間の比較(平成27年度年次講演会一般公演)

ダイズ品種「トヨハルカ」の耐倒伏性に関与する形質の同定 : 押倒し抵抗とその関連形質におけるトヨハルカとトヨムスメおよび耐倒伏性QTLの準同質遺伝子系統間の比較(平成27年度年次講演会一般公演)

水稲湛水土中散播栽培における耐倒伏性の解析 : 押倒し抵抗値と地上部・地下部諸形質との関係

水稲湛水土中散播栽培における耐倒伏性の解析 : 押倒し抵抗値と地上部・地下部諸形質との関係

Lodging resistance and yield potential of winter wheat: effect of planting density and genotype

Improved lodging resistance is important for achieving high yield in irrigated environments. This study was conducted to determine genotypic variation in lodging resistance and related morphological traits among winter wheat cultivars planted at two densities, and to identify key traits associated with lodging resistance. Lodging performance of 28 genotypes, including 24 released cultivars and four advanced lines, was evaluated at 250 plants per square meter and 500 plants per square meter in Shandong province during the 2008-2009 and 2009-2010 crop seasons. At the higher density, the average grain yield was 2.6% higher, even though lodging score rose by as much as 136%. The higher planting density increased lodging through increased leaf area index (LAI), plant height, center of gravity and length of basal internodes, and reduced grain weight per spike and diameter of the lower two stem internodes. LAI, center of gravity and diameter of first internodes, as the important indicators for lodging resistance, were significantly correlated with lodging score, with R= 0.62, 0.59 and -0.52 (P<0.01), respectively. Plant pushing resistance was significantly associated with diameter and length of the first internodes (R = 0.71-0.77, P<0.01), indicating it could be used to assess the strength of the lower stem. Higher planting density could be used to select genotypes with lodging resistance in irrigated environments. Cultivars carrying high plant density tolerance and high yield potential, such as Jimai 22 and Liangxing 66, were recommended as leading cultivars for production as well as elite crossing parents for further increasing yield potential in the Yellow and Huai Valleys Winter Wheat Zone in China.

In-hand haptic perception in dexterous manipulations

Dexterous in-hand manipulation with multi-finger robotic hands is a hot topic in robotics. Recently many famous multi-finger robotic hands have been developed. Though a lot of research has been done on them; in-hand manipulation is still a challenge. One of its issues lies in the uncertainty of interaction states. In this paper we research robot-object interaction from a novel angle called haptic exploration. This method helps robots acquire the ability to explore the robot-object interaction. In in-hand manipulation tasks, haptic exploration is a process where the robot pushes on in-hand objects slightly in different directions, and meanwhile perceives the haptic feedback to estimate the interaction state. In this paper a new single finger push model is proposed for analyzing the haptic feedback, which is similar to traditional impedance control of robot arm. In this model the stiffness of fingers, the deformation on contact surface, and the change of object’s pos (position and attitude) are considered. Furthermore, a push resistance is given to describe the haptic feedback acquired from a slight push. Finally, real robotic experiments are conducted to verify the feasibility of proposed method.