Diurnal Difference Research Articles

Prediction of Potential Suitability Areas for Ephedra sinica in the Five Northwestern Provinces of China Under Climate Change

Ephedra sinica (E. sinica) holds significant economic and medicinal importance and is predominantly found in arid areas. Due to the limitations of environmental variables, growth habits, and human activities, the production and suitability areas of E. sinica have significantly decreased, especially in the five northwestern provinces of China. In this study, 212 distribution points of E. sinica and 40 environmental variables were obtained to project the habitat suitability of E. sinica under different emission scenarios in the future. It identified precipitation in the wettest month, monthly mean of the diurnal temperature difference, and solar radiation intensity in April and July as the primary environmental factors affecting the suitability of E. sinica in the region. The areas of high, medium, and low suitability in the region cover 103,000 km2, 376,500 km2, and 486,800 km2. Under future scenarios, the suitability areas from 2021 to 2100 will decrease by 20%, with high suitability areas decreasing by 65% to 85% particularly. With comprehensive environmental variables, the suitability areas of E. sinica from 2021 to 2100 are projected, filling the gap in the projection of E. sinica suitability areas in the five northwestern provinces of China over long time period. The suitability areas show a significant decreasing trend. This research provides valuable insights into the suitability areas and crucial environmental factors, offering theoretical support for future protection and management efforts for E. sinica.

Assessing diurnal land surface temperature variations across landcover and local climate zones: Implications for urban planning and mitigation strategies on socio-economic factors

Rising temperatures and rapid urbanization globally reinforce the need to understand urban climates. We investigated the influence of land cover and local climate zones (LCZs) on diurnal land surface temperature (LST) in various seasons in greater Delhi region, India, and their implications on socio-economic factors. Day LST was the highest in the summer and night LST in the monsoon, which also had the lowest diurnal differences in LST. Higher height and density of built-up features contributed to greater heat at night. During the day, open built-up and vegetated areas experienced relatively less heat than their compact equivalents. The lowest diurnal difference was in medium height compact urban zones and tall vegetation. Social inequity in access to urban cooling was indicated by large low-income and heat-vulnerable populations inhabiting the hottest LCZs. This research highlighted that even in semi-arid and subtropical climates, spatial planning policy should consider both the seasonality and diurnal differences in temperature as much as appropriate morphologies for design of thermally comfortable and climate resilient urban spaces. These policies should address the evidenced social inequities in heat exposure to reduce the adverse health impacts on vulnerable groups and therefore contribute to wider societal and economic benefits of healthier populations.

Three birds with one stone strategy: A tri-modal radiator based on the cooling-compensation-heating effect

Passive radiative using solar energy for energy gain is receiving increasing attention as a green and sustainable energy supply method. However, passive radiative designs of existing materials are usually static and unsuitable for dynamic seasonal and weather changes. Here, we explore an efficient design of a temperature-adaptive thermal management sandwich structure that integrates passive daytime radiative cooling/heating and temperature control of phase change materials. Compared with conventional passive radiators, the developed phase change material-enhanced radiative cooler/heater (PDHM) can be flipped to adjust thermal management performance according to seasonal and diurnal temperature changes. The radiative cooling layer (PDRC) has a high solar reflectance (95%) and a high infrared emissivity (97%). The phase change layer (PCM) acts as an effective compensation for temperature, causing the PDRC cooling power to rise and fall by 15 W·m−2 during daytime and nighttime. The radiative heating layer (PDRH) has a low infrared emissivity (75.6%) and a high solar absorptivity (85.7%). The final PDHM aerogel achieves 11 °C below ambient temperature and 25 °C above ambient temperature under direct sunlight in summer and winter, and it leads to an increase in the average nighttime temperatures of 2.1 °C and 1 °C in summer and winter, reducing the diurnal temperature difference. Thus, the temperature-adaptive PDHM shows great potential for passive radiative regulation, which can further extend the application of passive radiators.

Surface urban heat island analysis based on local climate zones using ECOSTRESS and Landsat data: A case study of Valencia city (Spain)

Extreme heat events in cities are becoming more intense, frequent and prolonged. The spatiotemporal dynamics of surface temperature are closely related to land cover and atmospheric conditions, especially for urban areas with extensive surface heterogeneity. Two high spatial resolution satellites, ECOSTRESS and Landsat, provide land surface temperature (LST) for a typical Mediterranean climate city, Valencia, Spain. In total of 17 images throughout two heatwaves in the period of July and August from 2022 to 2023 were selected to monitor LST and surface urban heat island (SUHI). The Local Climate Zone (LCZ) scheme and hotspot analysis were applied to analyze the patterns of LST and SUHI during and after the heatwaves. Daytime images show LCZ 2/3/6/8 and LCZ C/E/F exhibit elevated SUHI intensity, meanwhile the LCZ 4, A/B and G have lower SUHI. The SUHI intensity of compact buildings (LCZ 1/2/3), LCZ 8/E/G are significantly higher at night, especially on heatwave days, the SUHI of all types increased by 0.1–0.9 °C. Furthermore, the meteorological parameters were introduced trying to explain the obvious diurnal difference of SUHI during heatwaves. This research serves as a proxy for understanding the spatiotemporal dynamics of SUHI during heatwave events, offering valuable insights for city planners and policymakers to enhance thermal comfortable level and effectively cope with extreme weather.

Short term temporal variability of selected organophosphate esters among healthy adults living in the National Capital Region of Canada

Organophosphate esters (OPEs) are used primarily as flame-retardants and plasticizers. OPEs are commonly detected in various environmental matrices, food and drinking water, and their metabolites are frequently found and quantified in urine. Potential adverse impacts on human health, including carcinogenicity, neurotoxicity, developmental and reproductive toxicity have been well documented. Urinary concentration of OPE metabolites can vary in the same individual, depending on the sampling time, thus introducing significant uncertainty in exposure assessment. The current study focusses on the assessment of short term temporal variability in adult men and women residing in Canada's Capital Region. Fifteen OPE metabolites were analyzed in 562 daily urine samples, collected every three days for five weeks from 11 volunteers. Sample extraction procedure was performed on an automated SPE and extracts analyzed using UPLC-MS/MS. In spot urine samples as well as first morning void (FMV), the detection frequency was greater than 50% for bis (2-chloroethyl) hydrogen phosphate (BCEP), bis (1-chloro-2-propyl) phosphate (BCIPP), bis (1,3-dichloro-2-propyl) phosphate (BDCIPP), diphenyl phosphate (DPHP) and bis(2,4-ditert-butylphenyl) hydrogen phosphate (B2,4DtBPP). Significant difference was observed in males and females for BCEP and BCIPP. Intra-class correlation coefficient (ICC) for creatinine corrected data for the spot urine samples ranged from 0.37 to 0.69. Good reproducibility was observed for creatinine corrected DPHP and BCIPP in both spot urine and FMV samples. More variation was observed between study participants in the spot urine samples when compared to the FMV samples. However, when considering diurnal difference there was a considerable inter-day variation in the FMV samples compared to the spot samples. The strength of the study is that the participants belonged to the same geographical location and working in the same facility, hence spatial variability did not influence the outcome of the results.

Effects of photoperiod on the growth and physiological responses in Ulva prolifera under constant and diurnal temperature difference conditions

Photoperiod and temperature are two main factors in the growth of macroalgae, and changes in photoperiod and diurnal temperature difference exist in natural condition. In order to study the effects of photoperiod and diurnal temperature difference on the growth of green algae Ulva prolifera, we cultured this species under three light/dark cycles (light: dark = 10:14, 12:12 and 16:08) with constant (22 °C for light and dark period, noted as 22-22 °C) and diurnal temperature difference (22 °C and 16 °C for light and dark period, respectively, noted as 22-16 °C) conditions. The results showed that: 1) Compared with 10:14 light/dark cycle, the growth of U. prolifera under 12:12 light/dark cycle was significantly enhanced by 39% and 16% for 22-22 °C and 22-16 °C treatments, respectively, while the increase proportion decreased when the daylength increase from 12 h to 16 h. 2) The enhancement in growth induced by diurnal temperature difference was observed under 10:14 light/dark cycle, but not for 12:12 and 16:08 light/dark cycle treatments. 3) The Chl a content and photosynthetic rate increased under short light period and 22-22 °C conditions, while under 22-16 °C conditions, higher photosynthetic rate was observed under 12:12 light/dark cycle and no significant difference in Chl a content was observed. 4) Under 22-22 °C conditions, compared with 10:14 (L:D) treatment, the expression levels of proteins in light-harvesting complexes, PSII and carbon fixation were down regulated, while the photorespiration and pentose phosphate pathway (PPP) were up regulated by 16:08 light dark cycle. Then we speculate that the higher photosynthetic rate may be one compensation mechanism in short photoperiod, and under long light period condition the up regulations of photorespiration and PPP can be in charge of the decrease in enhancement growth induced by longer daylength.

Transcriptomic Analysis for Diurnal Temperature Differences Reveals Gene-Regulation-Network Response to Accumulation of Bioactive Ingredients of Protocorm-like Bodies in Dendrobium officinale.

Dendrobium officinale Kimura et Migo (D. officinale) is one of the most important traditional Chinese medicinal herbs, celebrated for its abundant bioactive ingredients. This study demonstrated that the diurnal temperature difference (DIF) (T1: 13/13 °C, T2: 25/13 °C, and T3: 25/25 °C) was more favorable for high chlorophyll, increased polysaccharide, and total flavonoid contents compared to constant temperature treatments in D. officinale PLBs. The transcriptome analysis revealed 4251, 4404, and 4536 differentially expressed genes (DEGs) in three different comparisons (A: 25/13 °C vs. 13/13 °C, B: 13/13 °C vs. 25/25 °C, and C: 25/13 °C vs. 25/25 °C, respectively). The corresponding up-/down-regulated DEGs were 1562/2689, 2825/1579, and 2310/2226, respectively. GO and KEGG enrichment analyses of DEGs showed that the pathways of biosynthesis of secondary metabolites, carotenoid biosynthesis, and flavonoid biosynthesis were enriched in the top 20; further analysis of the sugar- and flavonol-metabolism pathways in D. officinale PLBs revealed that the DIF led to a differential gene expression in the enzymes linked to sugar metabolism, as well as to flavonol metabolism. Certain key metabolic genes related to ingredient accumulation were identified, including those involved in polysaccharide metabolism (SUS, SUT, HKL1, HGL, AMY1, and SS3) and flavonol (UGT73C and UGT73D) metabolism. Therefore, these findings indicated that these genes may play an important role in the regulatory network of the DIF in the functional metabolites of D. officinale PLBs. In a MapMan annotation of abiotic stress pathways, the DEGs with significant changes in their expression levels were mainly concentrated in the heat-stress pathways, including heat-shock proteins (HSPs) and heat-shock transcription factors (HSFs). In particular, the expression levels of HSP18.2, HSP70, and HSF1 were significantly increased under DIF treatment, which suggested that HSF1, HSP70 and HSP18.2 may respond to the DIF. In addition, they can be used as candidate genes to study the effect of the DIF on the PLBs of D. officinale. The results of our qPCR analysis are consistent with those of the transcriptome-expression analysis, indicating the reliability of the sequencing. The results of this study revealed the transcriptome mechanism of the DIF on the accumulation of the functional metabolic components of D. officinale. Furthermore, they also provide an important theoretical basis for improving the quality of D. officinale via the DIF in production.

The Lower Atmospheric Characteristics of Dust Storms Using Ground-Based Sensor Data: A Comparative Analysis of Two Cases in Jinan, China

Two severe dust storm (DS) events (15–17 March and 28–29 March) hit northern China in 2021 consecutively. The lower atmospheric vertical dynamic and thermal structures during the two cases were compared using the ground-based sensor data from the microwave radiometer and radar wind profiler, combined with the environmental and meteorological observations data in Jinan, China. It was found that both cases occurred under the background of cold vortexes over northeastern China. The dust was transported through the cold air on the northwest route. During the dust period, 2–3 km was the west or northwest airflow, and below 2 km was the northeast wind. The variation in the dynamic structure determined the duration of the DS. During the DS maintenance phase, the vertical wind shear (VWS) below 3 km measured approximately 10 m∙(s∙km)−1. The increased VWS during the dust intrusion period facilitated the transportation of dust. In contrast, the more significant VWS was not conducive to the maintenance of DS, and the shift to south wind control in the upper middle layer indicated the weakening of DS. In both cases, we observed a cliff-like decrease in relative humidity as a prominent indicator of dust outbreaks, occurring approximately 2–5 h beforehand. The diurnal difference between the vertical temperature and relative humidity during the dust maintenance period was found to be insignificant.

Diurnal variation in the urban thermal environment and its relationship to human activities in China: a Tencent location-based service geographic big data perspective.

The main factor of the formation and deterioration in China's urban thermal environment is human activity, which is difficult to describe and measure. A new perspective on the effect of human activity on the urban thermal environment can be obtained by examining the interaction between location-based service (LBS) data and the urban thermal environment in China. However, relevant research is still limited. In this study, we used Tencent LBS data, Terra/Aqua MODIS land surface temperature (LST) data, and land use data to investigate the relationship between LBS and the urban thermal environment, specifically the LST and surface urban heat island intensity (SUHII) across China and its provinces. Our results showed that (1) in summer, the heat island effect was an issue in 94% of the urban areas in China, which was worse during the day. The high- and low-value periods of LBS data on a given day coincided with the acquisition times of MODIS LST products during the day and at night, respectively. (2) During both the day and at night, there was a significant connection between LBS data and the urban thermal environment in China. The highest correlation coefficient (r) between LBS data and the LST could reach 0.55 (p < 0.01) at the provincial level, and the highest correlation coefficient (r) between LBS data and the SUHII could reach 0.78 (p < 0.01) at the provincial level. (3) The urban thermal environment diurnal difference and LBS data exhibited a significant relationship. The ΔLBS diurnal differences were significantly positively related to the SUHII diurnal differences in China. The overall study findings revealed that LBS data constitute an important parameter to represent the human activity intensity when investigating the formation of the urban thermal environment in China.

Diurnal Variation Characteristics of Raindrop Size Distribution Observed by a Parsivel2 Disdrometer in the Ili River Valley

The diurnal variation characteristics of raindrop size distribution (RSD) in the Ili River Valley are investigated in this study, using the RSD data from May to September during 2020-2021 collected by a Parsivel2 disdrometer in Zhaosu. Significant diurnal variations (02–07, 08–13, 14–19, and 20-01 local standard time (LST)) of precipitation and RSD in Zhaosu are revealed during the rainy seasons. Precipitation mainly occurs in the late afternoon and early evening. A higher concentration of small raindrops is observed in the morning, whereas more mid-size and large raindrops are observed in the afternoon. The RSD exhibits diurnal differences between different rainfall rate classes; the diurnal difference of RSD is more pronounced in the case of high rainfall rates. Stratiform precipitation can occur at any time of the day, yet convective precipitation mainly occurs during the late afternoon and early evening. The RSD of stratiform rainfall shows a similar distribution over the four time periods. For convective rainfall, the concentration of small raindrops is the highest (lowest) over 02–07 (14–19) LST, while the highest (lowest) concentration of medium and large drops is observed over 14–19 (02–07) LST. Convective rain in the Ili River Valley over 14–19 LST can be characterized as the continental convective cluster, while in the rest time of the day, it is neither in the maritime cluster nor in the continental cluster. The empirical relationships between the radar reflectivity factor and rainfall rate (Z-R) for stratiform and convective rain types are also derived. The purpose of this study is to advance our understanding of precipitation microphysics in arid mountainous region.

Interaction between air pollutants and meteorological factors on pulmonary tuberculosis in northwest China: A case study of eight districts in Urumqi.

Meteorological factors and air pollutants are associated with the spread of pulmonary tuberculosis (PTB), but few studies have examined the effects of their interactions on PTB. Therefore, this study investigated the impact of meteorological factors and air pollutants and their interactions on the risk of PTB in Urumqi, a city with a high prevalence of PTB and a high level of air pollution. The number of new PTB cases in eight districts of Urumqi from 2014 to 2019 was collected, along with data on meteorological factors and air pollutants for the same period. A generalized additive model was applied to explore the effects of meteorological factors and air pollutants and their interactions on the risk of PTB incidence. Segmented linear regression was used to estimate the nonlinear characteristics of the impact of meteorological factors on PTB. During 2014-2019, a total of 14,402 new cases of PTB were reported in eight districts, with March to May being the months of high PTB incidence. The exposure-response curves for temperature (Temp), relative humidity (RH), wind speed (WS), air pressure (AP), and diurnal temperature difference (DTR) were generally inverted "U" shaped, with the corresponding threshold values of - 5.411 °C, 52.118%, 3.513m/s, 1021.625hPa, and 8.161 °C, respectively. The effects of air pollutants on PTB were linear and lagged. All air pollutants were positively associated with PTB, except for O3, which was not associated with PTB, and the ER values for the effects on PTB were as follows: 0.931 (0.255, 1.612) for PM2.5, 1.028 (0.301, 1.760) for PM10, 5.061 (0.387, 9.952) for SO2, 2.830 (0.512, 5.200) for NO2, and 5.789 (1.508, 10.251) for CO. Meteorological factors and air pollutants have an interactive effect on PTB. The risk of PTB incidence was higher when in high Temp-high air pollutant, high RH-high air pollutant, high WS-high air pollutant, lowAP-high air pollutant, and high DTR-high air pollutant. In conclusion, both meteorological and pollutant factors had an influence on PTB, and the influence on PTB may have an interaction.

Diurnal difference of stable isotopes of precipitation in the summer half-year in Lanzhou City

Diurnal difference of stable isotopes of precipitation in the summer half-year in Lanzhou City

Diurnal differences in urine flow in healthy young men in a light-controlled environment: a randomized crossover design

BackgroundOlder men often experience nocturnal urination difficulties, reflected by diurnal differences in maximum urine flow (Qmax). Since lower urinary tract symptoms and pathological comorbidities are frequent in older men, it remains unclear whether this diurnal variation is a physiological or pathological phenomenon. Our aim was to quantify the diurnal variability of Qmax in healthy young participants under varying daylight conditions in a stable environment to discern potential underlying causes of nocturnal urination difficulties.MethodsTwenty-one healthy young men were recruited in a 4-day study utilizing daytime (08:00–18:00) exposure with two light conditions in randomized order: dim (< 50 lx) or bright (~2500 lx). Day 1 was for acclimation, and urine flow was assessed from day 2. The participants urinated ad libitum during day 2 and then at fixed 3–4-h intervals thereafter (days 3–4). Regular urination Qmax at late night (04:00) on day 4 was compared with the nearest voided volume during daytime of day 3 (mDay).ResultsMorning Qmax scores (after bed—11:00) on day 2 were significantly lower than evening (17:00—before pre-sleep) in bright conditions and those of daytime (11:00–17:00), evening (17:00—before pre-sleep), and pre-sleep in dim conditions. Pre-sleep Qmax during the ad libitum period was significantly higher in dim than bright conditions. Late-night Qmax values (04:00) on day 4 were significantly lower than Qmax scores of mDay on day 3 in both light conditions.ConclusionsHealthy young men had a clear diurnal Qmax difference that decreased during late night and morning. In addition, the pre-sleep Qmax values in dim daylight were significantly higher than in bright daylight. Taken together, we conclude that late-night and morning decreases in Qmax are an instinctive physiological phenomenon in humans, and the diurnal difference of Qmax can be influenced by daylight conditions.

Amine-functionalized MIL-101(Cr) fibers for direct air capture at cold temperatures using rapid temperature vacuum swing adsorption

Given that most of the world shows annual temperatures lower than 25 °C and some regions exhibit a large diurnal temperature difference in a single day, it is desirable to explore the CO2 sorption behavior of materials not only at ambient (25 °C) but also at cooler, “sub-ambient” conditions (defined here as < 25 °C). These cold temperatures may offer advantages for DAC such as higher gas adsorption capacities and lower absolute humidity, reducing concomitant water adsorption. Here, amine-functionalized MIL-101(Cr) fibers are evaluated at cold temperatures using rapid temperature vacuum swing adsorption (RTVSA). MIL-101(Cr)/cellulose acetate fibers loaded with macromolecular amines are evaluated as practical gas–solid contactors. As spun MIL-101(Cr) fibers show desirable properties for use as structured contactors such as high permeance and low pressure drop. Breakthrough and RTVSA experiments are conducted in the presence of humidity at sub-ambient temperatures to understand the CO2 adsorption and desorption behavior of the sorbent/contactor under conditions approaching practical operation. With optimized amine loading, the PEI-MIL-101(Cr) fibers give CO2 capacities comparable to the powder form of the sorbent, as well as sharp breakthrough curves at fast flow rates (1.4 m/s superficial velocity) suggesting the system is not limited by additional mass transfer resistances under the tested conditions. RTVSA shows fast desorption kinetics (14.4 mmol of CO2/g of fiber/h) at moderate desorption conditions, at 0.1 bar vacuum with temperatures below 80 °C. The entire cycle during RTVSA finishes in ∼ 25 min with ∼ 76 mol% CO2 purity as the product in this initial, modestly optimized study.

Analysis of the association between diurnal temperature difference and relative humidity and myocardial infarction in Shantou residents

Objective: To analyze the effect of meteorological conditions on mortality and population susceptibility of patients with acute myocardial infarction (AMI) in the Shantou area and to provide a scientific basis for the local public health system to prevent AMI. Methods: The AMI mortality data recorded in the resident cause of death surveillance database of Shantou from January 1, 2015, to December 31, 2020, were collected and the distribution lag nonlinear model was used to analyze the diurnal temperature range (DTR) and relative humidity (RH) on AMI mortality and the lag effect. Results: There were 13 932 deaths due to AMI in Shantou during the study period, with a male-to-female sex ratio of 1.3∶1. There was a significant association between high diurnal temperature difference exposure and low RH exposure and AMI deaths, with both single-day lag effects appearing and reaching a maximum at lag 2 day (RR=1.019, 95%CI: 1.000-1.039; RR=1.018, 95%CI: 1.003-1.034); the cumulative lag effect was all maximal at lag 0-14 day (RR=1.199, 95%CI: 1.025-1.401; RR=1.279, 95%CI: 1.117-1.465). The elderly (≥75 years) and female populations were susceptible to high DTR exposure and low RH exposure conditions. Conclusions: There was a significant association between DTR and RH and mortality of AMI in Shantou with a significant lag in their effects. Both female and elderly populations ≥75 years old were susceptible populations under high DTR and low RH exposure conditions.

Decoupling the response of vegetation dynamics to asymmetric warming over the Qinghai-Tibet plateau from 2001 to 2020

Global land surface air temperature data show that in the past 50 years, the rate of nighttime warming has been much faster than that of daytime, with the minimum daily temperature (Tmin) increasing about 40% faster than the maximum daily temperature (Tmax), resulting in a decreased diurnal temperature difference. The Qinghai-Tibet Plateau (QTP) is known as the "roof of the world", where temperatures have risen twice as fast as the global average warming rate in the last few decades. The factors affecting vegetation growth on the QTP are complex and still not fully understood to some extent. Previous studies paid less attention to the explanations of the complicated interactions and pathways between elements that influence vegetation growth, such as climate (especially asymmetric warming) and topography. In this study, we characterized the spatial and temporal trends of vegetation coverage and investigated the response of vegetation dynamics to asymmetric warming and topography in the QTP during 2001–2020 using trend analysis, partial correlation analysis, and partial least squares structural equation model (PLS-SEM) analysis. We found that from 2001 to 2020, the entire QTP demonstrated a greening trend in the growing season (April to October) at a rate of 0.0006/a (p < 0.05). The spatial distribution pattern of partial correlation between NDVI and Tmax differed from that of NDVI and Tmin. PLS-SEM results indicated that asymmetric warming (both Tmax and Tmin) had a consistent effect on vegetation development by directly promoting greening in the QTP, with NDVI values being more sensitive to Tmin, while topographic factors, especially elevation, mainly played an indirect role in influencing vegetation growth by affecting climate change. This study offers new insights into how vegetation responds to asymmetric warming and references for local ecological preservation.

Dynamic analysis of metabolomics reveals the potential associations between colonic peptides and serum appetite-related hormones

Gut signals, including hormones and metabolites are crucial zeitgebers that regulate the circadian rhythm of host metabolism, but the potential links have been explored more in rodents. Herein, we performed an hour-scale metabolomics analysis of serum and colonic digesta to characterize the circadian rhythmic metabolic patterns using a pig model under ad libitum feeding conditions. Importantly, our findings identified potential associations between colonic and body metabolism, revealing the potential relationships between colonic peptides and host appetite regulation. Concretely, amino acids accounted for the highest proportion in rhythmic serum metabolites, whereas lipids accounted for the highest proportion in rhythmic colonic metabolites. The diurnal difference analysis revealed that the levels of most amino acids and peptides were higher in the light phase, while the levels of most lipids were higher in the dark phase. And more correlations were be checked between serum amino acids, lipids, peptides and colonic metabolites in the light and more correlations were be checked between serum carbohydrates, cofactors and vitamins, energy, nucleotides, xenobiotics and colonic metabolites in the dark. Interestingly, peptides oscillated to a similar extent in serum and colonic digesta. Of note, colonic peptides composed of valine, proline and leucine were checked in positive associations to glucagon-like peptide-1 (GLP-1) in serum. And these peptides were positive with the genera Butyricicoccus, Streptococcus, Clostridioides, Bariatricus and Coriobacteriia_norank, and negative with Prevotella, and showed the potential relationships with colonic microbial biosynthesis of amino acids. Collectively, we mapped the rhythmic profiling on pig serum and colonic metabolites and revealed the relationships between host and gut metabolism. However, the underlying regulatory mechanisms remains to be further investigated.

Experimental investigation into effects of lignin on sandy loess

Promoted by the international Helin Airplane project where sandy loess is widely distributed, this study investigates the feasibility of improving the mechanical properties of sandy loess by using lignin, an environmentally friendly material. Considering the climatic conditions in the distribution area of sandy loess, such as strong evaporation and large diurnal temperature difference, extensive experiments including curing test, wet-dry cycle test, freeze–thaw cycle test, triaxial test, XRD test and SEM test are conducted to determine the strengthening effect of lignin on sandy loess. Test results show that 21 days are enough for lignin-modified sandy loess to complete curing and obtain maximum compressive strength, which increases with the increase of lignin content. Lignin has insignificant effect on the resistance of sandy loess to wet-dry cycles, but it can significantly improve the resistance to freeze–thaw cycles. Lignin causes significant alterations on the stress–strain relationship and mechanical response of sandy loess by mainly changing the cohesion while maintaining the frictional angle unchanged. SEM results show that lignin gradually plays the role of cementation, bonding, and fiber reinforcement with increasing content, and it mainly affects fine-grained soils while it has less effect on large particles. Good agreement between different experiments is obtained.

Rubber latex yield is affected by interactions between antecedent temperature, rubber phenology, and powdery mildew disease.

Rubber (Hevea brasiliensis) latex production is crucial to the local economy, yet Xishuangbanna's climate is considered sub-optimal for rubber cultivation. The prevalence of the powdery mildew disease (Oidium heveae) in this region has decreased the annual latex yield by 20%. Rubber latex yield is influenced by several factors, including temperature, disease, other biotic conditions, and plantation management. However, the interrelationships and potential influencing networks between rubber latex yield and these factors are rarely quantitatively assessed, and understanding their impacts on latex yield could inform better management practices. To address this gap, we investigated the effects of temperature, phenology, and powdery mildew disease on rubber latex yield in March using observational data on daily rubber latex yield combined with detailed phenology, powdery mildew, and temperature data from 2004 to 2010 in a state farm in the Xishuangbanna, Yunnan, China. We found that the critical influencing periods of daily temperature difference (or diurnal temperature difference) on the rubber latex yield were during Nov 27-Jan 19 and Jan 21-Mar 17. Partial least square regression analysis and variance partitioning analysis were conducted on the 35 phenological variables, eight powdery mildew-related variables, and two climatic variables. The most influential factors were identified as the factors of the daily temperature differences during Jan-Mar, the duration of leaf flushing phenology, and mean and maximum percentage of leaves infected by powdery mildew. Subsequent canonical correlation analysis and linear regression found that temperature difference directly affected the rubber latex yield and indirectly affected the yield through phenology and powdery mildew disease. Raised daily temperature differences from Jan to Mar had the greatest impact, leading to a higher rubber latex yield. Our comprehensive quantitative assessment revealed the relative importance of antecedent daily temperature differences, phenology, and powdery mildew disease as well as their complex interconnections in influencing rubber latex yield. Our findings are essential tofuture studies on both powdery mildew disease and rubber latex yield, and alsodevelop rubber latex models.

Enhanced daytime atmospheric mercury in the marine boundary layer in the South Oceans

Understanding the spatial and temporal variations of atmospheric mercury (Hg) in the marine boundary layer could advance our knowledge on ocean evasion of Hg. Here, we conducted continuous measurements of total gaseous mercury (TGM) in the marine boundary layer during a round-the-world cruise from August 2017 to May 2018. We observed the highest and lowest TGM concentrations in Southern Indian Ocean (1.29 ± 0.22 ng m−3) and Southern Atlantic Ocean (0.61 ± 0.28 ng m−3), respectively. During the daytime, enhanced TGM was observed with the diurnal amplitude difference reaching its maximum in the range of 0.30–0.37 ng m−3 in Southern Indian Ocean and Southern Ocean. The positive correlation between TGM (R2 = 0.68–0.92) and hourly solar radiation in each ocean suggested that the daytime enhanced TGM was likely driven by Hg photoreduction in seawater, after excluding the influence of other meteorological factors. The diurnal amplitude of TGM in the marine boundary layer might be impacted by the microbial productivity and the ratio of ultraviolet radiation. Our study highlights that ocean acts as a net TGM source during the daytime in the Southern Hemisphere and aqueous photoreduction process may play an important role in the biogeochemical cycling of Hg.