Variation in Root Biomass and Distribution Based on the Topography, Soil Properties, and Tree Influence Index: The Case of Mt. Duryun in Republic of Korea.

Root biomass and distribution are influenced by abiotic factors, such as topography and soil physicochemical properties, determining belowground productivity. Hence, we investigated the variation in root biomass and vertical root distribution based on the topography, soil physicochemical properties, and tree influence index, and their relationships, across soil depths (0-10 cm, 10-20 cm, and 20-30 cm) and topographical gradients in a warm-temperate forest in Mt. Duryun, Republic of Korea. Two contrasting research sites were established: a lower slope oriented at ≤3° and an upper slope with a slope of 30°. Each site comprised eleven 400 m2 sampling plots from which root samples from various diameter classes (<2 mm, 2-5 mm, 5-10 mm, and >10 mm) were collected. While the bulk density increased with soil depth in the lower slope, the organic matter, available phosphorus, Ca2+, and Mg2+ showed a reversed pattern. Linear mixed-effects models generally revealed significant negative correlations between root biomass and soil pH, total nitrogen, and cation exchange capacity, particularly in small roots (ßstd = -1.03 to -1.51) and coarse roots (ßstd = -6.30). Root biomass exhibited a 10-15% increase in the upper slope compared to the lower slope, particularly in fine (median = 52.0 g m2-65.64 g m2) and medium roots (median = 56.04 g m2-69.52 g m2) at a 0-20 cm soil depth. While no significant correlation between root biomass and the tree influence index was found on the lower slope, a different pattern was found on the upper slope. Our results indicate that the variation in root biomass and distribution can also be explained by the differences in the soil environment and topographical positions.

Fine-Root Distribution and Soil Physicochemical Property Variations in Four Contrasting Urban Land-Use Types in South Korea.

Urbanization and associated forest conversions have given rise to a continuum of native (forest fragments) and modified (artificial grasslands and perennial ecosystems) land-use types. However, little is known about how these shifts affect soil and fine-root compartments that are critical to a functioning carbon and nutrient circulation system. In this study, soil physicochemical properties, fine-root mass, and vertical distribution patterns were investigated in four representative urban land-use types: grassland (ZJ), perennial agroecosystem (MP), broadleaf deciduous forest patch (QA), and coniferous evergreen forest patch (PD). We quantified the fine-root mass in the upper 30 cm vertical profile (0-30 cm) and at every 5 cm depth across three diameter classes (<2 mm, 2-5 mm, and <5 mm). Soil physicochemical properties, except for phosphorus, nitrogen, ammonium nitrogen, and sodium cations, varied significantly across land-use types. The total root biomass (<5 mm) decreased in the order of QA (700.3 g m-2) > PD (487.2 g m-2) > ZJ (440.1 g m-2) > MP (98.3 g m-2). The fine-root mass of ZJ and MP was correlated with soil nutrients, which was attributed to intensive management operations, while the fine-root mass of QA and PD had a significant relationship with soil organic matter due to the high inputs from forest litter. Very fine roots (<2 mm) presented a distinct decremental pattern with depth for all land-use types, except for MP. Very fine roots populated the topmost 5 cm layer in ZJ, QA, and PD at 52.1%, 49.4%, and 39.4%, respectively. Maintaining a woody fine-root system benefits urban landscapes by promoting soil stabilization, improving ground infiltration rates, and increasing carbon sequestration capacity. Our findings underscore the importance of profiling fine-root mass when assessing urban expansion effects on terrestrial ecosystems.

Age Cutoff and Yield of Prompt Esophagogastroduodenoscopy to Detect Malignancy in Vietnamese with Upper Gastrointestinal Symptoms: An Endoscopic Database Review of 472,744 Patients from 2014 to 2019.

Background and Aims: Age cutoff is an important factor in deciding whether esophagogastroduodenoscopy (EGD) is necessary for patients presenting with upper gastrointestinal symptoms. However, the cutoff value is significantly different across populations. We aimed to determine the age cutoff for EGD that assures a low rate of missing upper gastrointestinal malignancy (UGIM) and to assess the yield of prompt EGD in Vietnamese patients presenting with upper gastrointestinal symptoms. Methods: All EGDs performed in outpatients during a 6-year period (2014-2019) at a tertiary hospital that provided an open-access endoscopy service were retrospectively reviewed. Repeat or surveillance EGDs were excluded. Different age cutoffs were evaluated in terms of their prediction of the absence of UGIM. The yield of endoscopy to detect one malignancy (YoE) was also calculated. Results: Of 472,744 outpatients presenting with upper gastrointestinal symptoms, there were 2198 (0.4%) patients with UGIM. The median age and male-to-female ratio of patients with UGIMs were 57.9 ± 12.5 years and 2.5 : 1, respectively. The YoEs in patients <40, 40-60, and >60 years of age were <1, 1-10, and >10 per 1000 EGDs, respectively. The age cutoffs of 30 years in females and 35 years in males could detect 98.2% (95% CI: 97.7%-98.8%) of UGIM cases with a YoE of about 1 per 1000 EGDs. Conclusions: The age cutoff for EGD in Vietnamese should be lower than that recommended by current international guidelines. The strategy of prompt EGD showed a low YoE, and its cost-effectiveness requires further investigation.

Role of alcohol in hospitalized road trauma in Viet nam.

OBJECTIVE: To assess the blood alcohol concentration (BAC; dependent variable) of patients with road traffic injuries (RTIs) presenting at 3 provincial and central hospitals in the Socialist Republic of Viet Nam by age, sex, and road user type (independent variables). This survey formed part of the Viet Nam Road Traffic Injury Prevention Project, funded by Bloomberg Philanthropies. INTRODUCTION: RTIs are a leading cause of death and disability in Viet Nam, with 14,690 deaths and 143,940 injuries reported by the Ministry of Health (MOH) in 2010. Research estimates suggest that motorcycle riders and passengers account for 60 percent of fatalities. Alcohol has long been suspected of being a leading cause of road traffic collisions and injuries. However, until now data on this relationship have been limited. METHODS: A descriptive cross-sectional study measuring BAC in all consenting patients with RTIs presenting at 3 provincial or central hospitals between July 2009 and September 2010. All results were anonymous and summary information on key variables was sent to MOH and the World Health Organization (WHO) on a monthly basis. RESULTS: Of the 36,418 patients with RTIs presenting to these 3 hospitals between July 2009 and September 2010, BAC analysis was completed on 14,990 patients (41.2%), representing all patients with RTIs 15 years of age and above who consented to anonymous testing. BAC results ranged from 0 to 0.589 g/dL blood, with a mean of 0.0441 g/dL being the average concentration among all tested patients. Of all patients tested, 56.8 percent had no detectable alcohol in their system. Motorcycle riders were most commonly represented in the tested sample (70.7%), with 27.8 percent having a BAC above the legal limit (0.05 g/dL). Car or other vehicle drivers represented 2.7 percent of the sample, with 63.4 percent tested having a BAC above 0 g/dL, the legal limit for these road users. CONCLUSIONS: The results of this preliminary study indicate that 29.1 percent of all car drivers and motorcycle riders presenting at hospitals with RTIs exceeded the legal BAC limit for operating a motor vehicle. Though further study is required, this is suggestive that strengthening the enforcement of drink-driving laws is an urgent national road safety priority.