Relationship between frailty and depressive symptoms in older adults: role of activities of daily living and sleep duration

IntroductionPrevious studies have demonstrated that frailty is associated with depressive symptoms among older people and significantly increase the risk of difficulty in activities of daily living (ADL). However, uncertainties remain regarding the mechanisms behind such relationship. The aim of this study was to investigate the mediating effect of ADL in the relationship between frailty and depressive symptoms among older adults in China, and to explore to what extend sleep duration moderated the association between ADL and depressive symptoms.MethodsIn this study, we carried out cross-sectional descriptive analysis and 1,429 participants were included in the analysis. A survey was conducted using questionnaires and instruments measuring frailty, depressive symptoms, ADL and sleep duration. Bootstrap analyses served to explore the impact of ADL in mediating frailty and depressed symptoms, as well as the effect of sleep duration in moderating ADL and depressive symptoms.ResultsCompared to the robust group, the mediating effects of ADL between frailty and depressive symptoms were significant in the prefrail group and the frail group. The interaction term between sleep duration and ADL was significantly presented in the regression on depressive symptoms. Specifically, the Johnson–Neyman technique determined a range from 8.31 to 10.19 h for sleep duration, within which the detrimental effect of frailty on depressive symptoms was offset.ConclusionSleep duration moderated the indirect effect of ADL on the association between frailty and depressive symptoms. This provides support for unraveling the underlying mechanism of the association between frailty and depressive symptoms. Encouraging older adults to enhance ADL and obtain appropriate sleep duration might improve depressive symptoms for older adults with frailty and prefrailty

A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic.

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world

Environmental Controls of Diurnal and Seasonal Variations in the Stem Radius of Platycladus orientalis in Northern China

Fine-resolution studies of stem radial variation over short timescales throughout the year can provide insight into intra-annual stem dynamics and improve our understanding of climate impacts on tree physiology and growth processes. Using data from high-resolution point dendrometers collected from Platycladus orientalis (Linn.) trees between September 2013 and December 2014, this study investigated the daily and seasonal patterns of stem radial variation in addition to the relationships between daily stem radial variation and environmental factors over the growing season. Two contrasting daily cycle patterns were observed for warm and cold seasons. A daily mean air temperature of 0 °C was a critical threshold that was related to seasonal shifts in stem diurnal cycle patterns, indicating that air temperature critically influences diurnal stem cycles. The annual variation in P. orientalis stem radius variation can be divided into four distinct periods including (1) spring rehydration, (2) the summer growing season, (3) autumn stagnation, and (4) winter contraction. These periods reflect seasonal changes in tree water status that are especially pronounced in spring and winter. During the growing season, the maximum daily shrinkage (MDS) of P. orientalis was positively correlated with air temperature (Ta) and negatively correlated with soil water content (SWC) and precipitation (P). The vapor pressure deficit (VPD) also exhibited a threshold-based control on MDS at values below or above 0.8 kPa. Daily radial changes (DRC) were negatively correlated with Ta and VPD but positively correlated with relative air humidity (RH) and P. These results suggest that the above environmental factors are associated with tree water status via their influence on moisture availability to trees, which in turn affects the metrics of daily stem variation including MDS and DRC

Trends in Different Grades of Precipitation over the Yangtze River Basin from 1960 to 2017

Under the background of global warming, the trends and variabilities of different grades of precipitation have significant effects on the management of regional ecosystems and water resources. Based on a daily precipitation dataset collected from 148 meteorological stations in the Yangtze River Basin from 1960 to 2017, precipitation events were divided into four grades (small, moderate, large, and heavy precipitation events) according to the precipitation intensity to analyze the temporal and spatial change trends of different grades of precipitation amounts and frequencies, and the influence of different grades of precipitation on total precipitation was also discussed in this study. The results revealed that small precipitation amounts over the Yangtze River Basin decreased significantly, with a rate of −1.22%/10a, while heavy precipitation amounts showed a significant increasing trend (4.27%/10a) during the study period. The precipitation frequency of small and total events decreased significantly, with rates of −3.86%/10a and −2.97%/10a, respectively. Regionally, from the upper reaches to the lower reaches of the Yangtze River Basin, the contribution rate of small precipitation amounts and frequencies to the total precipitation gradually decreased, while heavy precipitation amounts and frequencies increased. The different grades of precipitation in region II showed a decreasing trend due to its unique geographical features. Furthermore, a Pearson correlation analysis was used to analyze the response of precipitation to long-term air temperature, demonstrating that small and moderate precipitation amounts and frequencies were mainly negatively correlated with long-term air temperature and that heavy precipitation amounts showed a stronger positive correlation with long-term air temperature (13.35%/K). Based on this, the rate of change in heavy precipitation in the Yangtze River Basin may be higher under the background of climate warming, which will lead to greater risks of extreme floods in the future. Evaluating and predicting the trends of different grades can provide a theoretical reference for agricultural production, flood control, and drought mitigation

Topography- and Species-Dependent Climatic Responses in Radial Growth of Picea meyeri and Larix principis-rupprechtii in the Luyashan Mountains of North-Central China

Dendroecological techniques were used to examine the relationships between topographic aspects, climate factors and radial growth of Picea meyeri and Larix principis-rupprechtii in Luyashan Mountains, North-Central China. Four sites were selected at timberline and totally 67 trees and 134 cores were collected. Pearson correlation and regression surface analysis were conducted to reveal the growth-climate relationships. The results indicated that the two species both showed significant negative correlations with temperature during preceding November on the two topographic aspects. On both slope aspects, growth of P. meyeri exhibited significant negative correlations with precipitation in current June, whereas growth of L. principis-rupprechtii showed significant negative correlations with precipitation in preceding September. On north-facing slope, tree growth was limited by low temperature in early growing season, which not shown on south-facing slope. If climate warming continues, L. principis-rupprechtii may be more favored and a reverse between relationships with temperature and precipitation maybe occur in growth of trees. Treeline position on the north-facing slope may possess a greater potential for elevation shifting than the south-facing slope. Our results supply useful information for discussing the potential effect of future climate on the forest growth in North-Central China

Radial growth of two dominant montane conifer tree species in response to climate change in North-Central China.

North-Central China is a region in which the air temperature has clearly increased for several decades. Picea meyeri and Larix principis-rupprechtii are the most dominant co-occurring tree species within the cold coniferous forest belt ranging vertically from 1800 m to 2800 m a.s.l. in this region. Based on a tree-ring analysis of 292 increment cores sampled from 146 trees at different elevations, this study aimed to examine if the radial growth of the two species in response to climate is similar, whether the responses are consistent along altitudinal gradients and which species might be favored in the future driven by the changing climate. The results indicated the following: (1) The two species grew in different rhythms at low and high elevation respectively; (2) Both species displayed inconsistent relationships between radial growth and climate data along altitudinal gradients. The correlation between radial growth and the monthly mean temperature in the spring or summer changed from negative at low elevation into positive at high elevation, whereas those between the radial growth and the total monthly precipitation displayed a change from positive into negative along the elevation gradient. These indicate the different influences of the horizontal climate and vertical mountainous climate on the radial growth of the two species; (3) The species-dependent different response to climate in radial growth appeared mainly in autumn of the previous year. The radial growth of L. principis-rupprechtii displayed negative responses both to temperature and to precipitation in the previous September, October or November, which was not observed in the radial growth of P. meyeri. (4) The radial growth of both species will tend to be increased at high elevation and limited at low elevation, and L. principis-rupprechtii might be more favored in the future, if the temperature keeps rising

Spatial and Temporal Variation in Reference Evapotranspiration and Its Climatic Drivers in Northeast China

Reference evapotranspiration (ET0) is an important component of the global water cycle, and its long-term change directly influences the regional water supply and demand balance. Under the background of global change, investigating spatiotemporal trends in ET0 and its response to climate change is of great importance for the conservation and rational utilization of water resources. Based on daily climate data from 91 meteorological stations during 1960–2017 in Northeast China, this study calculated ET0 using the Penman-Monteith method and analyzed its spatiotemporal change trends and primary driving factors. The results show the following: (1) During 1960–2017, the annual ET0 in Northeast China showed a nonsignificant upward trend at a rate of 1.45 mm/10a. A mutation point of ET0 was detected in 1993. From 1960 to 1993, ET0 experienced a significant decrease (p p ET0. From 1994 to 2017, the evaporation paradox disappeared. (2) ET0 trend in Northeast China was significantly and positively related to altitude. In the lower altitude regions (ET0 generally decreased, while in the higher altitude areas (>500 m), ET0 displayed an upward trend. (3) Based on the results of multiple regression analysis, relative humidity was the primary driving factor for ET0 trends in Northeast China during 1960–2017. At diverse altitudes, the primary climatic factors influencing ET0 were different. In high-altitude areas (>500 m), the change in ET0 was mainly influenced by relative humidity, while wind speed was the primary driving factor at low altitudes (<500 m)

Ultralong cycling and wide temperature range of lithium metal batteries enabled by solid polymer electrolytes interpenetrated with a poly(liquid crystal) network

Solid polymer electrolytes (SPEs) that can work over a wide temperature range are highly desired to accelerate the commercial applications of solid lithium metal batteries (SLMBs). Herein, novel SPEs were fabricated via the in situ polymerization and immobilization of a nematic liquid crystal (LC) into a poly(vinylidene fluoride-co-hexafluoropropene)-hexafluoropropylene (P(VDF-HFP)) network under in situ UV irradiation in the presence of an ionic liquid (IL). The migration of Li+ ions in as-formed SPEs was enhanced intensively on account of the interpretation of the poly(liquid crystal) (PLC) network, which was confirmed by FTIR and DFT calculations. As-developed SPEs exhibit an ultra-high ionic conductivity of 1.79 mS cm(-1) at 20 degrees C, a high lithium-ion transference number of 0.64, and an electrochemical window up to 5.0 V. Due to these outstanding performances, Li/Li symmetrical cells containing as-obtained SPEs delivered an outstanding cycling stability of over 3500 h under a current density of 0.2 mA cm(-2). Moreover, a Li/LiFePO4 battery showed desirable cycling stability from 0 degrees C to 100 degrees C. It exhibited a high discharge capacity of 165.1 mA h g(-1), a high capacity retention of 95.1% after 500 cycles, and a high coulombic efficiency above 99.5% even under a 3C rate at 100 degrees C. Undoubtedly, these novel SPEs have great potential to be used in next-generation SLMBs

Influence of climate on seasonal and diurnal stem radius variations in Picea meyeri during cold seasons

Dendrometer-derived stem radius variations (SRV) have been demonstrated as useful tools to test cold acclimation, which could reflect the tree water (ice) balance in winter and thus the frost stress. However, most previous studies focus on stem increment and water relations during growing seasons, stem radius variations in cold seasons and the underlying tree physiological information are not fully exploited, limiting our understanding of the response of mid- and high-latitudinal forests to warming winter. Hourly SRV in spruces (Picea meyeri) across an elevational transect of 700 m were observed over 6 consecutive years (2012–2017) in the present study. Elevation-specific variations in the onset of stem freeze and thaw, and the magnitude of seasonal and diurnal SRV in cold seasons were explored, and ultimately their dominant environmental factors were determined. Before stem freeze, seasonal and diurnal SRV showed linear trends with elevation, which were mainly affected by air and soil water conditions. Whereas, after stem freeze, the seasonal SRV and thus the stem dehydration was greater at the lower and upper limits of the forest belt, and the daily amplitude of freeze-thaw cycles was greater at high elevations. The diurnal air temperature range dominantly controlled the SRV on different time scales after stem freeze. Stem freeze and thaw in P. meyeri was active when the daily minimum air temperature was -2.5 °C in our study region. The onset of stem freeze and thaw advanced and delayed with elevation corresponding to a rate of 5.2 and 7.5 days/ °C when adjusted for the monitored lapse rate of 0.63 °C per 100 m, respectively. Together these findings highlight the value of high-precision variations in stem size to indicate the potential freezing stress, and trees growing at high elevations might suffer greater stress caused by frost dehydration and freeze-thaw under ongoing climate change

Pearson’s correlation coefficients between each pair of chronologies.

<p>* and ** indicate the significant levels of 0.05 and 0.01, respectively; P1, P2, P3, P4, represent the chronologies of <i>P. meyeri</i> in the lowest, the lower, the higher and the highest sites, respectively; L1, L2, L3, L4 represent the chronologies of <i>L. principis-rupprechtii</i> in the lowest, the lower, the higher and the highest sites, respectively; the correlations are based on the common period 1978–2007.</p><p>Pearson’s correlation coefficients between each pair of chronologies.</p