Warm winters and high precipitation in north‐eastern Japan generate snow covers of more than three meters depth and densities of up to 0.55 g cm−3. Under these conditions, rain/snow ratio and snowmelt have increased significantly in the last decade under increasing warm winters. This study aims at understanding the effect of rain‐on‐snow and snowmelt on soil moisture under thick snow covers in mid‐winter, taking into account that snowmelt in spring is an important source of water for forests and agriculture. The study combines three components of the Hydrosphere (precipitation, snow cover and soil moisture) in order to trace water mobility in winter, since soil temperatures remained positive in winter at nearly 0.3°C. The results showed that soil moisture increased after snowmelt and especially after rain‐on‐snow events in mid‐winter 2018/2019. Rain‐on‐snow events were firstly buffered by fresh snow, increasing the snow water equivalent (SWE), followed by water soil infiltration once the water storage capacity of the snowpack was reached. The largest increase of soil moisture was 2.35 vol%. Early snowmelt increased soil moisture with rates between 0.02 and 0.035 vol% hr−1 while, rain‐on‐snow events infiltrated snow and soil faster than snowmelt and resulted in rates of up to 1.06 vol% hr−1. These results showed the strong connection of rain, snow and soil in winter and introduce possible hydrological scenarios in the forest ecosystems of the heavy snowfall regions of north‐eastern Japan. Effects of rain‐on‐snow events and snowmelt on soil moisture were estimated for the period 2012–2018. Rain/snow ratio showed that only 30% of the total precipitation in the winter season 2011/2012 was rain events while it was 50% for the winter 2018/2019. Increasing climate warming and weakening of the Siberian winter monsoons will probably increase rain/snow ratio and the number of rain‐on‐snow events in the near future.

Stable isotopes of xylem water ( 18 O and D) have been successfully used to determine sources of soil water for plant transpiration, but mainly in drought-prone environments. The water uptake strategies of three representative tree species in Japan, namely cedar (Cryptomeria japonica), larch (Larix kaempferi) and beech (Fagus crenata), were investigated using δ 18 O and δD of water (precipitation, soil and xylem), together with wood α-cellulose δ 13 C and δ 18 O, along one growing season. The study was carried out in the research forest of Yamagata University (Shonai region), a high precipitation area in Japan, which exceeds 3000 mm per year. Precipitation water δ 18 O and δD increased along the summer growing season, but oxygen and hydrogen isotopic composition of soil water remained essentially unchanged. In general, xylem water isotopes of cedar and larch followed the local meteoric water line, but beech xylem water was decoupled from soil and precipitation values in July and August. For this tree species, the xylem water isotopic records were more depleted than cedar and larch xylem water isotopic values and the precipitation water isotopic records, indicating that beech used more water from soil layers during July-August than the other two species, which mainly used newly-fallen precipitation. Wood δ 18 O showed an opposite seasonal trend to the one found for xylem water, likely because of leaf water isotope enrichment, which was in turn controlled by seasonal transpiration rate. The higher δ 13 C values of cedar during summer suggested that this species had enhanced water-use efficiency during the growing season compared with the deciduous species larch and beech. Our results highlight different water use strategies among forest tree species even in areas where the annual water balance is far from limiting plant performance.

<p>Yamagata prefecture, facing the Japan Sea, is one of the heavy snow fall regions of the world. Around half of the annual precipitation of around 3000 mm falls in winter as snow, producing snow covers of more than three meters depth.  However, air temperature is around 0°C in winter and therefore relatively warm. Hence, snow density becomes 0.5 g/cm³ already early in the snow accumulation phase. To qualify and quantify interactions, three spots on a slope, forested with Japanese cedar (Cryptomeria japonica), have been selected to compare relationships on top, at the middle and at the bottom of snow covered slopes. The site represents the majority of mountain forests in north-eastern Japan. Monitoring soil and air temperature as well as precipitation and soil moisture we found strong interactions between the three hydrological regimes (precipitation, snow cover and soil) in winter. Soil did not freeze and hence volumetric soil moisture content changed during the winter season. Several sharp significant increases of soil moisture have been measured before the snow melt period even started. High rates of soil moisture increase together with an increase of Snow Water Equivalent (SWE) have been found to be caused by rain-on-snow events. In contrast, smaller rates of soil moisture increase in peaks were correlated with a decrease in SWE and therefore a snowmelt process. The interactions of snow cover and soil have been found to be different in the three different spots at the slope. Soil at the bottom of a slope reacts significantly to the highest number of events; soil on the slope reacts only to some events, but more intensively. Thus, most of the water is moving within the snowpack down the slope, increasing the SWE. Thereafter water reaches the soil surface and infiltrates it. This has been found to be also one reason for the formation of depth hoars and therefore the risk of avalanches.</p><p>To conclude, hydrological regimes in north-eastern Japan interact during the whole year due to winter air temperatures around 0°C and soil which does not freeze. The shape of peaks in soil moisture can be used to distinguish between rain and snowmelt causing the soil moisture increase. Various preferential flow patterns at different spots on a slope are an excellent basis for further studies and a basis for further monitoring and modelling. </p>

BackgroundN6-methyladenosine (m6A) RNA modification play critical roles in tumorigenesis because it can change gene expression and even the function in multiple levels including the regulation of degradation, subcellular localization, splicing and local conformation changes of RNA transcripts. In this study, we aim to conduct comprehensive investigation on m6A RNA methylation regulators and m6A-related genes and their association with prognosis in early-stage Lung adenocarcinoma (LUAD). MethodsThe relevant datasets which were used to analyze 21 m6A RNA methylation regulators and 887 m6A-related genes in m6Avar were downloaded from Gene Expression Omnibus database (GEO) and The Cancer Genome Atlas (TCGA) databases. Univariate cox regression analysis, random survival forest analysis, Kaplan-Meier anylysis, STRING and multivariate cox analysis were carried out on the datasets, and a risk prognostic model based on five feature genes was constructed.ResultsRespectively, we treated GSE31210 (n=226) as training set, GSE50081 (n=128) and TCGA data (n=461) as test set. By performing univariable cox regression and random survival forest algorithm in the training group, five prognosis-related genes including DENND1A, KBTBD6, KIF4A, BMPER, and YTHDC2 were screened out, which could divide LUAD patients into low-risk group and high-risk group (log rank P < 0.001). The predictive efficacy of these genes was confirmed in the test group GSE50081 (log rank P < 0.01) and TCGA datasets (log rank P < 0.001). Cox analysis showed that this five-gene signature was an independent risk factor in LUAD. Further, genes in the signature were also external validated using online database. YTHDC2 played vital role of readers in m6A methylation.ConclusionThe findings of this study suggested that associated with m6A-related genes and m6A RNA methylation regulators, five-gene signature was reliable prognostic indicator for LUAD patients, indicating a clinical application prospect to serve as a potential therapeutic target.