Seasonal Changes Research Articles

Heavy metals toxicity in edible bivalves and risk exposure to humans through its consumption from Adyar Estuary, Tamilnadu, India – A baseline study

The Adyar estuary, situated at the heart of Chennai city, India, has been subjected to significant anthropogenic pollution over the past decade due to rapid urbanization and industrialization.This study endeavored to explore the bioaccumulation patterns of heavy metals within bivalve species including Perna viridis, Mercenaria mercenaria, and Lamellidens marginalis. Additionally, it aimed to assess the concentrations of heavy metals present in water samples obtained from ten discrete stations within the Adyar estuary across different seasonal periods. To better understand the dynamics of contamination, metal pollutants including Cd, B, Cu, Fe, Mn, Pb, and Zn were analyzed in the soft tissues (Gill, Kidney, and Muscle) of the bivalves using Atomic Absorption Spectrophotometer (AAS) (ELICO's SL- 176). The study also investigated the seasonal changes in biochemical constituents affecting the nutritional quality of these edible bivalves following conventional methods, and estimated the risk (both carcinogenic and non-carcinogenic) to consumers. Results showed that the biochemical constituents of Perna viridis and Mercenaria mercenaria were comparatively lower than those of the freshwater bivalve Lamellidens Marginalis (p > 0.05). Heavy metal accumulation in the mussels followed the order Mn > Zn > Cu > Pb > Fe > Cd > B. The highest uptake of metals by the bivalves occurred during the post-monsoon season, while the least uptake was observed during the monsoon season. The overall metal burden for the studied species followed the descending order M. mercenaria >P. viridis >L. marginalis. The study indicated that both carcinogenic and non-carcinogenic risks to humans from consuming these mussels were higher due to the excessive accumulation of metals Zn and Mn in all three studied bivalves.

Self-attention network-based state of charge estimation for lithium-ion batteries with gapped temperature data

The accurate estimation of the state of charge (SOC), a critical indicator of the energy stored in lithium-ion batteries, is essential for ensuring reliable and safe battery management. The influence of temperature on the battery characteristics substantially affects the SOC estimation accuracy. Owing to the broad operational temperature range of batteries, it is vital to address the various temperature conditions. This study proposes a model structure for data-driven SOC estimation to enhance accuracy under diverse temperature conditions. The model leverages the analysis of the SOC characteristics derived from the measured data. The proposed structure incorporates parallel-connected self-attention and long-short-term memory modules, thus providing an innovative approach for effectively capturing intricate features in SOC estimation. This study primarily focused on evaluating the capability of the proposed model to achieve satisfactory SOC estimation for untrained temperature conditions when trained with gapped temperature data, thus emphasizing its practicality. To assess the feasibility of the proposed method, experiments were performed under a broad range of fixed and varying temperature conditions, including seasonal and daily changes. The experimental results demonstrated that the root-mean-square errors of the estimated SOC were 0.4101% and 1.5611% at fixed and time-varying temperatures, respectively, including the subzero ranges. These results highlight the robustness of the proposed model under various temperature conditions and its applicability to real-world battery operational temperatures.

Spatiotemporal changes in the community and demography of mesozooplankton in the eastern Indian sector of the Southern Ocean during austral summer 2018/2019

The Southern Ocean is facing rapid environmental changes. However, few studies have been conducted on the spatiotemporal variability of mesozooplankton communities under recent climatic conditions, particularly in the eastern Indian sector. This study describes the spatiotemporal variability of the mesozooplankton community and the demographics of large copepods and krill in this sector, sampled through a Rectangular Mid-Water Trawl with 1 m2 mouth area (RMT1) during the austral summer of 2018/2019 as part of the KY1804 survey. Cluster analysis indicated that the mesozooplankton community was divided into five groups that showed only small longitudinal differences, as they were affected by oceanic fronts. Part of the variability was explained by physical (local upwelling) and biological features (e.g., the occurrence of species showing a specific spatial distribution, such as Euphausia crystallorophias). Horizontal changes in the zooplankton community structure were not attributed to temporal changes during the 2-month sampling period. The demographics of the dominant species, Calanoides acutus, Calanus propinquus, Metridia gerlacheri, and Thysanoessa macrura, exhibited significant temporal differences in abundance or mean stage index (MSI) between the early and late seasons. These differences matched the growth rates estimated in previous studies, suggesting that their growth during the study period was constant without regional differences. There were no evident changes in the abundance or demographics of Rhinalanus gigas, suggesting that they were in their reproductive season. These species-specific demographics could be explained by the species life cycles: growth in C. acutus and C. propinquus and reproduction in R. gigas during the austral summer. Abundances and MSIs confirmed the growth of dominant copepods and krill during the sampling period; however, no evident seasonal changes were observed in the zooplankton community structure. The findings of this study contribute to the understanding of lower trophic levels in marine ecosystems and the present carbon cycle in the eastern Indian sector of the Southern Ocean.

Effect of temperature on seasonal wind power and energy potential estimates in Nordic climates

AbstractA major obstacle standing in the way of full‐scale adoption of renewable energy sources is their intermittency and seasonal variability. To better understand the power generation dynamics, the effect of air density due to temperature on power and energy generation figures was modelled. The model uses historical ERA5 data and considers changes in weather patterns in a subarctic climate where seasonal changes are most pronounced. The power generation figures of using a mean and a dynamic air density value were compared and the results show that power generation estimates may be under‐ and overestimated by on average 5% up to 10% in winter and summer, respectively. This can have implications for the sizing of power transmission infrastructure and energy storage in both on‐grid and off‐grid applications as well as power availability. The topic is highly relevant in the Nordic countries where roughly 10% of new global added wind capacity is installed annually.

Enhanced relationship between seasonal soil moisture droughts and vegetation under climate change over China

Climate change could intensify seasonal soil moisture droughts and subsequently degrade vegetation, but it can also facilitate vegetation growth with the rising temperature and CO2 concentrations. Therefore, the change of the vegetation-drought relationship under climate change remains elusive. Here, we investigate the effects of vegetation greening (i.e., increasing leaf area index (LAI)) on seasonal soil moisture drought trends by performing a set of land surface model simulations with the Conjunctive Surface-Subsurface Process model version 2 (CSSPv2), as well as the impact of seasonal soil moisture drought change on vegetation productivity via a statistical fitting model. Our results indicate that both the impact of increasing LAI on exacerbating seasonal droughts and the impact of increasing seasonal droughts on reducing vegetation productivity have been enhanced over China during 1961–2018. Specifically, increased LAI accounts for 48 % of the rising drought frequency through escalated evapotranspiration losses, with more pronounced effects in northern semiarid regions. The decrease in vegetation stomatal conductance caused by rising CO2 concentrations limits transpiration and alleviates 11 % of the increase in drought frequency, but it cannot fully offset the drought aggravation induced by increased vegetation water consumption under climate warming. Meanwhile, increased drought frequency and intensity have reduced the upward trend in vegetation productivity by 5 % over China, and by 8 % in water-limited northern regions. Our study shows the relationship between seasonal soil moisture droughts and vegetation over China has strengthened, indicating that vegetation greening will lead to increased water shortages and further impact vegetation growth and carbon sequestration. This challenges water resources management and environmental sustainability, especially in semiarid regions.

Influence of probiotic strains on growth performance, carcass characteristics and seasonal changes of growing New Zealand white rabbits.

This experiment was designed to explore how different types of probiotics affect the growth, carcass traits, and seasonal variations in growing New Zealand White rabbits (NZW). Two parallel experiments using the same strain of NZW during winter and summer, each alone from 5 to 13 weeks of age. Each experiment uses a total of 125 unsexed rabbits. These rabbits are separated into 5 groups of 25 rabbits each. Each group has five replicates, with five rabbits in every replicate. In each experiment, 1st group acting as the control group did not receive any probiotics. The 2nd was given a dose of 1ml of Bifidobacterium bifidum, the 3rd received a dose of 1ml of Lactobacillus acidophilus, and the 4th was treated with a 1ml blend of both Bifidobacterium bifidum and Lactobacillus acidophilus, and 5th group was treated with 1ml of Saccharomyces cerevisiae. Results indicated that the Bifidobacterium bifidum group had the best live body weight (LBW) values and daily weight gain (DWG). Meanwhile, during summer, the Lactobacillus acidophilus group had the best feed conversion ratio (FCR) and performance index (PI) values. Also, growing rabbits fed Lactobacillus acidophilus and Bifidobacterium bifiduim had significantly increased carcass traits during the summer and winter seasons. Furthermore, seasonal changes indicated that the Bifidobacterium bifiduim group improved LBW, DWG, and PI during summer than winter. So, it could be concluded that using Bifidobacterium bifidum can enhance rabbit growth by improving feed utilization and carcass traits, making it an effective addition to hot weather diets.

Initial monitoring of a six-story lightweight timber frame building under different environmental conditions

AbstractThis study presents a comprehensive investigation of the dynamic behavior of a six-story lightweight timber frame building through periodic and continuous ambient vibration tests. Seasonal changes in temperature and relative humidity can influence the dynamic response of timber buildings, by affecting stiffness, strength, and connection properties due to changes in moisture content. Systematic tests were performed from October 2022 until May 2024 to identify natural frequencies, damping ratios, and mode shapes of the building using five battery-driven data acquisition units equipped with 15 uni-axial accelerometers. Two different only-output frequency and time domain Operational Modal Analysis (OMA) methods were used to evaluate the dynamic properties of the building. Additionally, the building has been continuously monitored with temperature and humidity sensors since its construction. Results obtained from the periodic measurements highlighted the need for a permanent system to capture the transient changes in the modal parameters. A complementary permanent system to record the accelerations at the roof level was installed in May 2024. The modal parameters from in situ measurements were compared with those obtained from the Finite Element (FE) model of the structure. The FE model, calibrated through a multi-stage approach, incorporating non-structural elements, and varying imposed loads, showed good agreement with experimental data. Comparative analysis of the results obtained under different temperature and humidity conditions showed the effect of the environmental conditions on the building dynamics properties, for both periodic and permanent measurements. This study highlights the importance of continuous monitoring and detailed FE modeling in understanding the dynamic properties and long-term structural behavior under varying conditions. This information can be used to ensure that the building meets safety and performance requirements and to identify potential issues that may need to be addressed during the design and maintenance phases.

Temperature-Induced Seasonal Dynamics of Brain Gangliosides in Rainbow Trout (Oncorhynchus mykiss Walbaum) and Common Carp (Cyprinus carpio L.).

This study aimed to determine the expression and distribution of gangliosides in specific regions of the brains of rainbow trout (Oncorhynchus mykiss Walbaum) and common carp (Cyprinus carpio L.) with regard to seasonal temperature changes. Seasonal changes in ganglioside expression and distribution within the species were expected. The natural ecosystems of these fishes differ significantly due to their distinct habitat preferences, geographic distributions, and environmental requirements. Based on the fact that the common carp is eurythermic and adapts to a wide range of temperatures, while the rainbow trout is stenothermic and thrives in a narrower temperature range, it was expected that these species would exhibit distinct patterns of ganglioside modification as part of their adaptive response to temperature fluctuations. Immunohistochemistry using specific antibodies for the major brain gangliosides (GM1, GD1a, GD1b, GT1b), along with the Svennerholm method for quantifying sialic acid bound to gangliosides, revealed that cold acclimatization led to an increase in polysialylated gangliosides in the common carp brain and an increase in trisialogangliosides in the rainbow trout brain. Immunohistochemical analysis also identified region-specific changes in ganglioside expression, suggesting specific functional roles in neuronal adaptation. These results supported the hypothesis that the composition and distribution of brain gangliosides change in response to seasonal thermal shifts as part of the adaptive response. The results underscore the importance of gangliosides in neuronal function and adaptation to environmental stimuli, with implications for understanding fish resilience to temperature changes. This study offers valuable insights into species' temperature adaptation, with implications for physiological and ecological management and improved aquaculture practices. Future research could expand the species scale, study molecular mechanisms and regulatory pathways in ganglioside metabolism, and examine ganglioside interactions with membrane proteins and lipids for a deeper understanding of thermal adaptation.

Seasonal changes in the total mercury in small mammals in forest ecosystems near Cherepovets town, Vologda region

Mercury is one of the most dangerous environmental pollutants due to its high toxicity to animals and humans. The aim of the study was to determine the presence or absence of seasonal changes in the mercury level in small mammals in forest ecosystems near the Cherepovets town. The fur, organs and tissues of the common shrew (Sorex araneus Linnaeus, 1758) and Ural field mouse (Apodemus uralensis Pallas, 1811) were examinied during September 2020–August 2021. The content of total mercury (THg) in dried samples (n = 319) was determined on a PA-915+ mercury analyzer with a PYRO console by cold vapor atomic absorption. The content of THg in the Ural field mouse varies from <0.001 (sensitivity limit of the device) in the kidneys, spleen, brain, muscles, and liver up to 0.560 mg/kg dry weight in the spleen; the average maximum THg value was found in the spleen (0.179±0.072 mg/kg) and the minimum was in the muscles (0.023±0.011 mg/kg). The content of THg in the common shrew varies from <0.001 (sensitivity limit of the device) in the brain up to 4.570 mg/kg dry weight in the fur, the average maximum THg value was found in the fur (0.754±0.152 mg/kg), and the average minimum was in the liver (0.112±0.013 mg/kg). It was established that the level of THg in common shrews was higher in winter than in summer, statistically significant differences were found for the fur, muscles, and liver (p = 0.008, 0.001, 0.033, respectively, at p < 0.05). An interspecies comparison showed differences in seasonal changes in the THg content, namely: in autumn it was higher in the common shrew than in the Ural field mouse; statistically significant differences were found for the fur, kidneys, and muscles (p = 0.005, 0.046, 0.001, respectively, at p < 0.05).

Experimentally Elevated Levels of Testosterone Advance Daily Onset of Activity in Short-Day Housed Male House Sparrows (Passer domesticus).

Seasonal changes in sleep/wake cycles and behaviors related to reproduction often co-occur with seasonal fluctuations in sex hormones. Experimental studies have established that fluctuations in circulating testosterone mediate circadian rhythms. However, most studies are performed under constant lighting conditions and fail to investigate the effects of testosterone on the phenotypic output of circadian rhythms, that is, chronotype (daily activity patterns under light:dark cycles). Here, we experimentally elevated testosterone with implants during short nonbreeding daylengths in male house sparrows (Passer domesticus) to test if observed seasonal changes in chronotype are directly in response to photoperiod or to testosterone. We fitted individuals with accelerometers to track activity across treatment periods. Birds experienced three treatments periods: short day photoperiods before manipulation (SD), followed by testosterone implants while still on short days (SD + T). Implants were then removed. After a decrease in cloacal protuberance size, an indicator of low testosterone levels, birds were then photostimulated on long days (LD). Blood samples were collected at night, when testosterone peaks, to compare testosterone levels to daily onset/offset activity for experimental periods. Our results indicate that experimentally elevated testosterone under short nonbreeding photoperiods significantly advanced daily onset of activity and total daily activity relative to daylength. This suggests that testosterone, independent of photoperiod, is responsible for seasonal shifts in chronotypes and daily activity rhythms. These findings suggest that sex steroid hormone actions regulate timing of daily behaviors, likely coordinating expression of reproductive behaviors to appropriate times of the day.

Monthly, Annual and Seasonal Changes in Temperature by Using Mann Kendall and Sen’s Slope Estimator in Karnataka, India

The mean annual minimum temperature during the period 1979-2019 has increased significantly in Eastern dry zone, Southern dry zone and Southern transition zone to a cumulative of total of 0.010°C, 0.013°C and 0.08 °C respectively while it has decreased significantly in Hilly zone with a magnitude of -0.032°C. The annual maximum temperature significantly increased in North eastern transition zone (0.018°C), North eastern dry zone (0.017°C), Northern dry zone (0.014°C), Central dry zone (0.010°C), Eastern dry zone (0.011°C), Southern dry zone (0.013°C), Southern transition zone (0.016°), Northern transition zone (0.016°C) and Coastal zone (0.018°C). The hilly zone experienced a decrease in annual maximum temperature by-0.055°C. Therefore, it is evidential that, Karnataka is getting raised over the years. Researchers should develop crop varieties that are insensitive to temperature changes and scientist should develop packages of practices which will reduce adverse effect of fluctuations in climate parameters on crop productivity.

Comparative Analysis of Rhizosphere Fungal Communities in Korean Fir Trees

The Korean fir (Abies koreana), a native coniferous species of Korea, predominantly inhabits the subalpine zone. Recently, this species has experienced a significant population decline, primarily attributed to environmental changes in the subalpine zone driven by global warming. Efforts to prevent the extinction of the Korean fir are underway, with a predominant focus on abiotic factors contributing to its decline. However, there is a notable lack of research on the complex interactions between microbial communities and Korean fir, particularly concerning how these interactions vary with the health status of the trees and their impact on population sustainability. Therefore, this study aimed to elucidate the rhizosphere fungal community structure associated with Korean fir trees in Jirisan National Park. We examined different habitat types, including the rhizospheres of native, cultivated, and dead Korean fir and bulk soil. Our findings revealed that the rhizosphere fungal community in the natural habitat of Korean fir predominantly comprises Agaricomycetes. Furthermore, the fungal community structure was more responsive to habitat type variations than seasonal changes. These findings provide basic information for conserving this endangered species and developing alternative habitats for the Korean fir.

A Binned Multilevel Regression Fitting Method for Monitoring Geladandong Glacier Elevation Changes from ICESat-2 Data

ABSTRACT Studying glacier changes is essential for understanding global glacier mass balance, patterns in climate change, and the potential consequences they may have. The glaciers of Geladandong Mountain serve as a crucial water source for the Yangtze River and its downstream regions. Any changes in the glacier at the river source will directly impact the ecological environment and water recycling process downstream. This study presents an approach for monitoring Geladandong Mountain glacier elevation changes using ICESat-2 data combined with a Binned Multilevel Regression Fitting Method (BMRFM). We analysed multi-year ICESat-2 data, considering various topographic features, to understand glaciers’ annual and seasonal elevation changes. Our research reveals significant spatial heterogeneity in glacier elevation changes, influenced by altitude, slope, and aspect factors. It demonstrates the effectiveness of ICESat-2 in glacier monitoring, offering insights into the impacts of climate change on glacier dynamics. Moreover, the results indicate a predominant trend of ongoing melting at lower altitudes, with a small amount of accretion at higher elevations. Over the last two decades, the overall elevation change rate is −0.23 ± 0.12 metres per year. Seasonal analysis shows substantial glacier thickening from April to August, primarily due to increased precipitation offsetting elevated temperatures. This study offers a robust method for monitoring glaciers using satellite data, thereby advancing the precision and reliability of glacier research.

Establishing Neuron-Specific Enolase Reference Intervals: A Comparative Analysis of Partitioned Approach- and Gender-Based Continuous Age- and Season-Related Models.

Background/Objectives: Static reference intervals (RIs) fail to capture the dynamic changes in bioanalytes. This study aimed to develop gender-based continuous age- and season-related RIs for neuron-specific enolase (NSE) using real-world data and to compare them with partitioned RIs. Methods: The NSE results from 4097 individuals were included after rigorous screening. Partitioned RIs were determined using the Hoffmann method. Generalized additive models for location, scale and shape (GAMLSS) were selected to develop continuous RIs. Results: The partitioned RIs are as follows: <16.4 µg/L for males aged ≥19 years; <14.47 µg/L for females aged 19-49 years; and <17.25 µg/L for females aged ≥50 years. For continuous RIs, NSE levels in males remain stable with age, while in females, NSE levels evidently increase around the age of 50. Although less impactful than age, seasonal changes still affect NSE levels. Dynamic changes and continuous RIs for NSE are visualized in this study. Conclusions: We developed gender-based continuous age- and season-integrated RIs for NSE in North China, highlighting the variation in NSE levels in females with age and season. Compared to static RIs, continuous RIs are more responsive to NSE, potentially enhancing the precision and individualization of health assessments.

Differences in seasonal dynamics and pyrethroid resistance development among Anopheles Hyrcanus group species

BackgroundThe Anopheles Hyrcanus group, which transmits Plasmodium vivax, consists of six confirmed species in South Korea. An epidemiological study revealed differences in the seasonal occurrence patterns of each species. Pyrethroid resistance in An. sinensis dates back to the early 2000s, whereas information on pyrethroid resistance in other species is lacking despite their greater significance in malaria epidemiology.MethodsAnopheles mosquitoes were collected from two malaria-endemic regions in South Korea for 2 years and their knockdown resistance (kdr) mutations were genotyped. The larval susceptibility to λ-cyhalothrin was compared in six Anopheles species and its seasonal changes in three species were investigated. The full-length sequences of the voltage-sensitive sodium channel (VSSC) were compared across six species to evaluate potential target-site insensitivity. The contribution of the kdr mutation to phenotypic resistance was confirmed by comparing median lethal time (LT50) to λ-cyhalothrin between populations of Anopheles belenrae with distinct genotypes.ResultsThe composition and seasonal occurrence of rare species (Anopheles kleini, Anopheles lestri, and Anopheles sineroides) varied considerably, whereas An. sinensis occurs continuously throughout the season. A kdr mutation in the form of heterozygous allele was newly identified in An. belenrae, An. lesteri, An. pullus, and An. sineroides. The baseline susceptibility to λ-cyhalothrin was the highest in An. belenrae, followed by An. lesteri, An. sineroides, An. kleini, An. pullus, and An. sinensis, with median lethal concentration (LC50) values ranging from 6.0- to 73.5-fold higher than that of An. belenrae. The susceptibility of An. sinensis and An. pullus varied by season, whereas that of An. belenrae remained stable. The kdr-heterozygous An. belenare population exhibited 5.1 times higher LT50 than that of the susceptible population. Species-specific VSSC sequence differences were observed among the six species.ConclusionsOur findings suggest that the status and extent of pyrethroid resistance vary among Anopheles Hyrcanus group species. While An. sinensis, the predominant species, developed a considerable level of pyrethroid resistance through kdr mutation, the resistance levels of other species appeared to be less pronounced. Large-scale monitoring is crucial to fully understand species-specific seasonal occurrence and resistance status for effective management strategies, considering the ongoing impact of climate change on their vectorial capacity.Graphical

Optimization strategies for green power and certificate trading in China considering seasonality: An evolutionary game-based system dynamics

China has adopted renewable portfolio standards and tradable green certificates (including hydropower) to increase the proportion of green power used and reduce carbon emissions. However, hydropower generation is affected by seasonal factors, making it difficult to increase green power consumption in water-scarce areas. Trading electricity and green certificates in regions with different resource endowments can effectively solve this problem. Therefore, this study uses evolutionary game theory to explore the impact of the change in the policy of issuing green certificates for hydropower on the strategic choices of the trading parties. Based on the evolutionary game model, a system dynamics model is established to explore the optimization strategies of green power and certificate trading under the influence of seasonal factors. The results of the case study show that (1) the price of green certificates varies with seasonal changes. (2) Sellers with abundant hydropower resources should increase the amount of hydropower connected to the grid during the water-abundant period to help deficit areas achieve their consumption targets (3) Expanding the scope of green certificates can gradually eliminate government subsidies and incentives and reduce the government's financial pressure.

Disentangling seasonal and annual precipitation signals in the tropics over the Holocene: Insights from δD, alkanes and GDGTs

Rainfall seasonality in the tropics has a substantial impact on both ecosystems and human livelihoods. Yet, reconstructions of past rainfall variability have so far generally been unable to differentiate between annual and seasonal precipitation changes. Past variations in seasonality are therefore largely unknown. Here, we disentangle hydrogen isotopic (δD) signals from terrestrial leaf waxes and algae in an 8000-year peat core from Sumatra, which reflect annual versus wet season rainfall signals, respectively. We validate these results using lipid biomarkers by reconstructing vegetation dynamics via n-alkane distributions and peatland hydrological conditions using glycerol dialkyl glycerol tetraethers (GDGTs), as well as biomass burning using levoglucosan concentrations in the core. Finally, we compare our proxy results to a transient climate model simulation (MPI-ESM1.2) to identify the mechanism for seasonality changes. We find that algal δD indicates stronger Indonesian-Australian Summer Monsoon (IASM) precipitation in the Mid-Holocene, between 8 and 4.2 cal ka BP. A period of alternating flooding, droughts and wildfires is reconstructed between 6 and 4.2 cal ka BP, implicating very strong monsoonal precipitation and drying out and burning during a longer and intensified dry season. We attribute this strong rainfall seasonality in the Mid-Holocene mainly to orbitally forced insolation seasonality and a strengthened IASM, consistent with the modeling results. In terms of annual rainfall, terrestrial plant δD, vegetation composition and GDGTs all indicate wetter conditions peaking between 3 and 4.5 cal ka BP, preceded by drier conditions, followed by drastic and rapid drying in the late Holocene from around 2.8 cal ka BP. Our multiproxy annual precipitation reconstruction thereby indicates the wettest overall conditions approximately 1500–2000 years later than a nearby speleothem δ18O record, which instead follows the seasonally biased algal δD in our record. We, therefore, hypothesize that speleothem reconstructions over the Holocene in parts of the tropics with low but significant seasonality may carry a stronger seasonal component than previously suggested. The data presented here contribute with new insights on how isotopic rainfall proxies in the tropics can be interpreted. Our findings resolve the seasonal versus annual components of Holocene rainfall variability in the Indo-Pacific Warm Pool region, highlighting the importance of considering seasonality in rainfall reconstructions.

Prediction of emergency department presentations for acute coronary syndrome using a machine learning approach

The relationship between weather and acute coronary syndrome (ACS) incidence has been the subject of considerable research, with varying conclusions. Harnessing machine learning techniques, our study explores the relationship between meteorological factors and ACS presentations in the emergency department (ED), offering insights into seasonal variations and inter-day fluctuations to optimize patient care and resource allocation. A retrospective cohort analysis was conducted, encompassing ACS presentations to Dutch EDs from 2010 to 2017. Temporal patterns were analyzed using heat-maps and time series plots. Multivariable linear regression (MLR) and Random Forest (RF) regression models were employed to forecast daily ACS presentations with prediction horizons of one, three, seven, and thirty days. Model performance was assessed using the coefficient of determination (R²), Mean Absolute Error (MAE), and Mean Absolute Percentage Error (MAPE). The study included 214,953 ACS presentations, predominantly unstable angina (UA) (94,272; 44%), non-ST-elevated myocardial infarction (NSTEMI) (78,963; 37%), and ST-elevated myocardial infarction (STEMI) (41,718; 19%). A decline in daily ACS admissions over time was observed, with notable inter-day (estimated median difference: 41 (95%CI = 37–43, p = < 0.001) and seasonal variations (estimated median difference: 9 (95%CI 6–12, p = < 0.001). Both MLR and RF models demonstrated similar predictive capabilities, with MLR slightly outperforming RF. The models showed moderate explanatory power for ACS incidence (adjusted R² = 0.66; MAE (MAPE): 7.8 (11%)), with varying performance across subdiagnoses. Prediction of UA incidence resulted in the best-explained variability (adjusted R² = 0.80; MAE (MAPE): 5.3 (19.1%)), followed by NSTEMI and STEMI diagnoses. All models maintained consistent performance over extended prediction horizons. Our findings indicate that ACS presentation exhibits distinctive seasonal changes and inter-day differences, with marked reductions in incidence during the summer months and a distinct peak prevalence on Mondays. The predictive performance of our model was moderate. Nonetheless, we obtained good explanatory power for UA presentations. Our model emerges as a potentially valuable supplementary tool to enhance ED resource allocation or future predictive models predicting ACS incidence in the ED.

Quercus acutissima exhibits more adaptable water uptake patterns in response to seasonal changes compared to Pinus massoniana

BackgroundSeasonal precipitation variability significantly affects water use in forests; however, whether water uptake is adapted to changes in precipitation, particularly whether it could affect the coexistence of tree species, has rarely been quantified in forest systems. MethodIn this study, dual stable isotopes and the Li-6400 portable photosynthesis system were used to determine the water sources of a mixed conifer (Pinus massoniana) and broadleaf (Quercus acutissima) forest and changes in hydraulic characteristics during the dry and wet seasons in a southern hilly region of China. ResultsAlthough the hydraulic characteristics of P. massoniana were lower than those of Q. acutissima, it maintained a stable water source from the deep soil layer and a higher stomatal conductance (Gs), leading to a higher transpiration rate (Tr) during the growing seasons. Q. acutissima mainly absorbed water from deeper soil layers in the dry season and took up from shallow soil layers in the wet season. Its Gs values exhibited sensitivity to precipitation, while it maintained a lower Tr value during the growing seasons. The excessive water-use strategy observed in P. massoniana may confer weak drought-tolerance during higher frequency and more intense extreme precipitation events, whereas Q. acutissima may exhibit better ecological adaption to precipitation changes. ConclusionsThe overlap of water niches in mixed forests did not appear to affect the coexistence of tree species. The present study provides insights into reforestation and water management in the southern hilly regions of China.

Chronological events unfolding the vegetative and floral phenology of apical bud in Crocus sativus.

Saffron (Crocus sativus L.) is an infertile perennial geophyte considered the most expensive spice in the world. Seasonal fluctuations and climate change have significant impact on the growth, development, and yield of saffron stigma, which is the economically valued part of plant. The stigma being part of the flower, the knowledge of phenotypic transition from dormant apical bud up to flowering is vital, yet, not explored properly. The complexity of flowering in C. sativus further accentuates by the lack of clear demarcation between flowering and non-flowering corms in terms of weight and sizes, as small corms are known to be vegetative only, while large ones produce flower. Therefore, chronological phenotyping on a weekly and quarterly basis of apical shoot and flowering primordia between June and October was carried out to understand the organogenesis sequentially. In large corms, the stamen was the first floral organ to initiate followed by the formation of tepal from the base of the stamen. The plants exhibited both synanthous and hysteranthous flowering. Untargeted metabolome analysis of dormant apical bud just before dormancy break from flowering buds from large corms as well as non-flowering buds from small corms identified the presence of many differentially accumulated metabolites including sphingosine and meglutol. Key metabolites such as phytosphingosine, 3-hydroxy-3-methyl glutaric acid, 3-acetamidopropanal, 6-hydroxykynurenic acid, D-serine, and 1-D-myo-inositol 3-phosphate were also detected having associated with isoprenoid biosynthesis, lignin pathway regulation, and carbohydrate metabolism that participates in flowering. The integration of morphological, histological, and metabolomic data offers a comprehensive view of the flowering process that can be utilised in future biotechnological interventions in C. sativus.