Contact mats estimate countermovement jump (CMJ) height via flight time, assuming consistent body positioning at take-off and landing. However, foot landing technique, specifically soft versus stiff landings, may alter ankle and joint angles, potentially biasing jump height measurements. This study investigated the effect of externally cued ankle-focused landing styles- specifically ball-of-foot (“soft”) versus heel-first (“stiff”) landings on CMJ height measured by a contact mat in collegiate male team sport athletes. One hundred male team sport athletes (age 21.4 years; height 182.3 cm; weight 78.6 kg) performed CMJs under randomized, counterbalanced soft (ball-of-foot, greater plantar flexion) and stiff (heel-first, minimal plantar flexion) landing conditions. Jump height was measured with the Just Jump contact mat using the Bosco protocol. Participants completed three trials per condition; average jump heights obtained under the soft and stiff landing conditions were compared using paired t-tests, while Pearson correlation and Bland-Altman analysis assessed the relationship and agreement between two landing styles. CMJ height was significantly greater during stiff landings (48.50 ± 5.51 cm) compared to soft landings (45.62 ± 5.80 cm), with a mean difference of 2.88 cm (p = 0.001, Cohen’s d = 1.28). A strong positive correlation (r = 0.92) indicated consistent ranking across conditions, but Bland-Altman analysis revealed systematic bias and moderate variability between landing styles. Landing technique substantially influences CMJ height measurements using a contact mat, with stiff landings producing inflated jump heights. However, this preliminary study did not include biomechanical verification of landing mechanics, which should be considered in future research.These findings highlight the need for standardized, explicit ankle landing instructions during CMJ testing to ensure accuracy and comparability of results in sport performance assessment and monitoring.
Urban roadside environments are characterized by altered microclimate and soil conditions that impose recurrent drought stress on trees, affecting their physiological performance and adaptive capacity. Understanding species-specific physiological and structural responses to drought stress is crucial for selecting tree species that are suitable for urban environments. In the present study, we investigated the species-specific and temporal (monthly) patterns of the in situ leaf physiological status and structural traits of two riparian tree species, Quercus robur L. and Carpinus betulus L., cultivated as urban roadside trees in Novi Sad, Serbia, throughout the growing season (from June to September). This was achieved by assessing leaf gas exchange and rapid light curves of chlorophyll a fluorescence together with leaf structural traits. Under drought stress, Q. robur exhibited sustained photosynthetic activity and transpiration rates due to reduced stomatal sensitivity, indicative of a more anisohydric behavior with respect to its water relations strategy. In contrast, C. betulus exhibited tighter stomatal regulation and showed lower assimilation rates accompanied by reduced cooling capacity, indicating stricter, more conservative water-balance management indicative of isohydric species. Fluorescence indices revealed contrasting behavior: C. betulus showed enhanced NPQ values accompanied by a decline in photosynthetic efficiency, while Q. robur exhibited lower NPQ, suggesting better maintenance of photosynthetic performance and electron transport in PSII under the observed drought stress. These patterns were further supported by higher stomatal density combined with smaller stomatal size, indicating faster stomatal response rates in C. betulus compared to Q. robur. Overall, these results suggest that C. betulus is a more promising riparian tree species for urban landscapes, particularly under drought-prone conditions and predicted climate changes, in comparison to Q. robur.
Up to date, the development of highly efficient, visible light-active catalysts remains a formidable challenge due to the enhanced rising of atmospheric CO2 concentration. This study discusses a class of ceria-based high-entropy oxides designed to optimize charge carrier dynamics, surface reactivity, and CO2 activation efficiency. Due to the advantages of high configurational entropy and multi-element synergy, these materials achieved improved photocatalytic performance, surpassing conventional ceria-based systems. Structural and spectroscopic analyses reveal that Pr3+/Pr4+ redox pairs and abundant oxygen vacancies create an electronically disordered yet thermodynamically stable environment, which enhances charge separation and suppresses electron-hole recombination. Photocatalytic experiments demonstrated that Ce0.2Zr0.2La0.2Pr0.2Sm0.2O2-delta (CZLPS) achieves the highest CO2 conversion rate, reaching a conversion of 20.3% under visible light irradiation, significantly surpassing pure ceria (1.4%), with a calculated space-time yield (STY) of 10.15 mol(CO)kg(-1)h(-1) under the same conditions. First-principles density functional theory (DFT) simulations were employed to investigate the CO2 reduction mechanism on CZLPS catalysts. The study elucidates the Gibbs free energy changes (Delta G) for each step of the reaction pathways leading to CO and HCOOH formation, highlighting the Zr site of CZLPS as the most active for the CO2RR, which is responsible for the outstanding catalytic activity
This study analyzes trends in three temperature variables (average annual air temperature, maximum air temperature, and minimum air temperature) for 72 time series from 24 meteorological stations in Central Serbia, spanning from 1949 to 2018. Data was sourced from meteorological yearbooks on the website of the Republic Hydrometeorological Institute of Serbia. Three statistical approaches were used: trend equation, trend magnitude, and the non-parametric Mann-Kendall (MK) trend test. GIS was applied to visualize geospatial data distribution. The results indicate a temperature increase in 66 of the 72 time series, with the largest increase of 4.3 degrees C and the smallest of 0.2 degrees C. Temperature decreases were recorded in 6 time series, with the largest decrease of-0.5 degrees C. The MK trend test revealed a statistically significant positive trend in 53 time series. Geospatial analysis showed varying temperatures across the region, with average annual air temperatures ranging from 10.6 degrees C in Dimitrovgrad to 18.1 degrees C in Belgrade. These findings offer insights into climate change in Central Serbia, highlighting areas of temperature increase and decrease, and provide a foundation for future climate research and strategy development.
