Increasing Levels Of Competition Research Articles

Hyperspectral remote sensing to assess weed competitiveness in maize farmland ecosystems

Weed competition causes serious economic losses to maize production. Timely and accurate assessment of pressure from competition is crucial for ecological weed management. In this work, we apply hyperspectral remote sensing (HRS) technology to conduct a competitive experiment in Harbin, China, in 2021, with 5-leaf maize as the study target. A weed competition assessment method that combines comprehensive competition indices (CCI) and deep learning is proposed. For the comprehensive competition assessment, the relationship between different weed competitive pressures (Levels 1–5) and changes in the structural and physiological information of maize was analyzed. The accumulative/transient competition indices CCI-A and CCI-T were designed for accurate quantification. The results showed that parameters such as plant height, stalk thickness and nutrient elements of maize decreased with increasing competition level. Parameters, such as stomatal conductance and transpiration rate, showed a fluctuating change of increasing and then decreasing with increasing competition level. Compared with the traditional relative competitive intensity (RCI), the standard deviation of CCI is 0.303 and 0.499. The dispersion effect of CCI is better and more suitable for quantifying the competition response. HRS images combined with 3D-CNN model were then applied to reveal the spectral response to different weed competition pressures (Levels 1–5) and to make early predictions of weed competition. The first-order derivative showed that the spectral reflectance exhibited significant differences at 520–525 nm peak, 570–655 nm trough, and near 700 nm red edge. For hyperspectral spatial-spectral features, the 3D-CNN model is proposed for prediction of competing indices CCI. In addition, the VIP method is used to select the characteristic wavelengths. The 3D-CNN model achieves a prediction accuracy of RMSE = 0.106 and 0.152 using 13 feature bands, which can accurately quantify the subtle changes in competition indices. Overall, this study shows that the combination of CCI and deep learning can provide a multivariate and comprehensive assessment of weed competition pressure.

Comparison of Anterior Cruciate Ligament Injury Rates In High School and Middle School Sports Over a 30-year Period

Background:Anterior cruciate ligament (ACL) injuries are a major concern in interscholastic sports. Comparison of ACL injuries between high school (HS) and middle school (MS) athletes over multiple years is limited.Purpose:To examine the incidence of ACL injury in HS female [HS-F] and male [HS-M], and MS female [MS-F] and male [MS-M] sports over a 30-year period.Methods:We studied 55,147 athletes who competed in interscholastic sports at a secondary school from 1988 to 2018. Data included ACL injuries incurred during interscholastic sports, and clinically confirmed by a physician. Injury rates per 100,000 AEs (practice and games where the athlete was at risk of ACL injury) were calculated for gender, sport, and contact status. Incidence rate ratios [RR] and 95% confidence intervals (CIs) were used to compare injury rates.Results:The incidence rate of ACL injury for HS athletes (4.15/100,000 AEs) was almost three times greater (RR=2.63, 95%CI: 1.7-4.2; p<0.0001) than the incidence rate for MS athletes (1.58/100,000 AEs). The risk of sustaining an ACL injury among HS-F athletes (4.26/100,000 AEs) was similar to HS-M athletes (4.06/100,000 AEs) (RR=1.05, 95%CI: 0.7-1.6; p=0.81). The risk of sustaining an ACL injury among MS-F athletes (1.06/100,000 AEs) was less than MS-M athletes (1.96/100,000 AEs) (RR=0.54, 95%CI: 0.2-1.4; p=0.21). While the risk of incurring an ACL injury occurrence was four times greater (RR=4.01, 95%CI: 1.7-9.4; p=0.0002) among HS-F athletes than MS-F athletes, the risk of ACL injury was twice as high (RR=2.08, 95%CI: 1.2-3.7; p=0.009) among HS-M athletes than MS-M athletes. ACL injuries were incurred in 15 HS sports and was greatest for HS-F basketball (25.5/100,000 AEs; p<0.001), HS-M football (20.6/100,000 AEs), and HS-F soccer (20.4/100,000 AEs). ACL injuries were sustained in 7 MS sports and was highest for MS-F softball (9.1/100,000 AEs), MS-M basketball (6.3/100,000 AEs) and MS-M football (5.0/100,000 AEs). The risk of contact-related ACL injury (1.73/100,000 AEs) was almost two times greater than non-contact-related ACL (0.96/100,000 AEs) (RR=1.80, 95%CI: 1.2-2.7; p<0.001). The rate of contact ACL injury was highest among HS-M (3.38/100,000 AEs) while the rate for noncontact ACL injury greatest among HS-F (2.44/100,000 AEs).Conclusions:The risk for ACL injury is higher in HS than in MS for both sexes. Non-contact ACL injuries were more likely to occur among HS-F athletes while contact injuries were highest for HS-M athletes, suggesting the effects of maturation and competition may play a role with increasing competition level.

Relative Efficiency of Canadian Banks: A Three-Stage Network Bootstrap DEA

In this study, we focus on how banks can enhance their efficiency in the utilization of resources to ensure their economic sustainability. We propose a novel three-stage (production, investment, and revenue generation) network Data Envelopment Analysis (DEA) with bootstrapping to evaluate the performance of the six big Canadian banks for the period 2000–2017, amid the 2007 financial crisis and the increasing competition level due to new technologies. We identify the best practices in each stage that can be used as benchmarks by other banks to improve their economic sustainability. Our results indicate that the 2007 financial crisis resulted in lower efficiencies in the performance of Canadian banks. This decline was not substantial for the production and investment stages when the revenue generation stage received the greatest hit. In addition, we observed that the individual banks did not have consistent performance in the different stages. Finally, we compared our model with the black box DEA model and concluded that the network DEA provides more insightful and accurate results in terms of banks’ efficiencies.

A New Ala-122-Asn Amino Acid Change Confers Decreased Fitness to ALS-Resistant Echinochloa crus-galli

Gene mutations conferring herbicide resistance may cause pleiotropic effects on plant fitness. Knowledge of these effects is important for managing the evolution of herbicide-resistant weeds. An Echinochloa crus-galli population resistant to acetolactate synthase (ALS) herbicides was collected in a maize field in north-eastern Italy and the cross-resistance pattern, resistance mechanism and fitness costs associated to mutant-resistant plants under field conditions in the presence or absence of intra-specific competition were determined. The study reports for the first time the Ala-122-Asn amino-acid change in the ALS gene that confers high levels of cross-resistance to all ALS inhibitors tested. Results of 3-year growth analysis showed that mutant resistant E. crus-galli plants had a delayed development in comparison with susceptible plants and this was registered in both competitive (3, 7, and 20 plants m-2) and non-competitive (spaced plants) situations. The number of panicles produced by resistant plants was also lower (about 40% fewer panicles) than susceptible plants under no-intraspecific competition. Instead, with the increasing competition level, the difference in panicle production at harvest time decreased until it became negligible at 20 plants m-2. Evaluation of total dry biomass as well as biomass allocation in vegetative parts did not highlight any difference between resistant and susceptible plants. Instead, panicle dry weight was higher in susceptible plants indicating that they allocated more biomass than resistant ones to the reproductive organs, especially in no-competition and in competition situations at lower plant densities. The different fitness between resistant and susceptible phenotypes suggests that keeping the infestation density as low as possible can increase the reproduction success of the susceptible phenotype and therefore contribute to lowering the ratio between resistant and susceptible alleles. If adequately embedded in a medium or long-term integrated weed management strategy, the presence of R plants with a fitness penalty provides an opportunity to minimize or reverse herbicide resistance evolution through the implementation of integrated weed management, i.e., all possible control tools available.