Historical Variables Research Articles

Sediment core records and impact factors of polycyclic aromatic hydrocarbons in Chinese lakes

Lake sediment is a natural sink for polycyclic aromatic hydrocarbons (PAHs). PAH sedimentation characteristics and their impact factors of Chinese lakes have mainly been qualitative assessed. However, quantitative impacts of PAH sedimentation from different factors have not been well analyzed. To fill this gap, we screened PAH sedimentation records from the literature, for 51 lakes in China and other regions of the world, to identify historical concentration variation and the impact factors of PAHs in different regions, in lake sediment. The results show that PAH concentrations in the sediment core in the selected Chinese lakes (478 ± 812 ng/g dry weight (dw)) were significantly lower than those in North America (5518 ± 6572 ng/g dw) and Europe (3817 ± 4033 ng/g dw). From 1900 to 2015, most of the lakes in China showed an increasing trend of PAH sedimentation concentrations, with the lakes in Southeastern China showed a decreasing trend of PAH concentration in the period of 2001–2015, which was later than the peak times shown in Western countries (1941–1970). The 2-3-ring PAHs were the main components in the sediment core of Chinese lakes, but the proportion to the total PAHs decreased from 72% in 1900–1940 to 55% in 2001–2015. Generalized additive modeling (GAM) was adopted to simulate the associations between PAH sedimentation records and the impact factors. There are large regional variations of economic and industrial development in China. The impact factors of PAH accumulation in the lake sediments differ in different regions. However, population and the consumption of coal, pesticides, and fertilizer were identified to be the most important impact factors influencing PAH sedimentation. The Chinese government needs to strengthen control measures on pollutant discharge to reduce the anthropogenic impact of PAH sedimentation in lakes.

Observed and projected trends in spring flood discharges for the Upper Harricana River, eastern boreal Canada

Study regionIn northwestern Québec, the Upper Harricana River is representative of the Abitibi Plains’ hydrological dynamics over the last 250 years. Study focusPlanning for future spring flood risks involves uncertainties. This research presents a multicentury evaluation of changes in spring mean discharge and flood drivers using streamflow reconstruction (1771–2016), observations (1915–2020) and projections (2021–2100). New hydrological insights for the regionUsing a downscaled CMIP5 ensemble of 10 global climate models (GCMs), generalized additive mixed modeling of mean spring discharge projections matched those of an independent mechanistic model and eight GCMs projected variability in spring discharge by 2100 to be similar to the historical variability reconstructed for the last 250 years across the Abitibi Plains. Results indicate that the projected decline in snow cover (–20 to –30% annual snowfall) and rise in winter and spring temperature may be offset by a greater contribution of rainfall to spring high discharge (+100 to +125 mm). However, two GCMs projected an increase in the magnitude and frequency of high mean spring discharge for the Abitibi Plains. By investigating future mean spring discharge for the Upper Harricana River in reference to past reconstructed variability, this study provides insights to inform the future management of regional water resources. The importance of estimating future regional flood risks from the behavior of multi-model ensembles is highlighted.

Diversification processes in Gerp's mouse lemur demonstrate the importance of rivers and altitude as biogeographic barriers in Madagascar's humid rainforests.

Madagascar exhibits exceptionally high levels of biodiversity and endemism. Models to explain the diversification and distribution of species in Madagascar stress the importance of historical variability in climate conditions which may have led to the formation of geographic barriers by changing water and habitat availability. The relative importance of these models for the diversification of the various forest-adapted taxa of Madagascar has yet to be understood. Here, we reconstructed the phylogeographic history of Gerp's mouse lemur (Microcebus gerpi) to identify relevant mechanisms and drivers of diversification in Madagascar's humid rainforests. We used restriction site associated DNA (RAD) markers and applied population genomic and coalescent-based techniques to estimate genetic diversity, population structure, gene flow and divergence times among M. gerpi populations and its two sister species M. jollyae and M. marohita. Genomic results were complemented with ecological niche models to better understand the relative barrier function of rivers and altitude. We show that M. gerpi diversified during the late Pleistocene. The inferred ecological niche, patterns of gene flow and genetic differentiation in M. gerpi suggest that the potential for rivers to act as biogeographic barriers depended on both size and elevation of headwaters. Populations on opposite sides of the largest river in the area with headwaters that extend far into the highlands show particularly high genetic differentiation, whereas rivers with lower elevation headwaters have weaker barrier functions, indicated by higher migration rates and admixture. We conclude that M. gerpi likely diversified through repeated cycles of dispersal punctuated by isolation to refugia as a result of paleoclimatic fluctuations during the Pleistocene. We argue that this diversification scenario serves as a model of diversification for other rainforest taxa that are similarly limited by geographic factors. In addition, we highlight conservation implications for this critically endangered species, which faces extreme habitat loss and fragmentation.

الاعتبارات الاقتصادية والدستورية في تخصيص مسؤوليات الإنفاق في الدول الفدرالية

This study discusses the assignment of spending responsibilities in federal countries, taking into account both economic and constitutional considerations. According to the theory of fiscal federalism, the economic functions of governments contain resource allocation, stabilization, and redistribution. However, it is also important to consider constitutional considerations, as federal systems are based on constitutions and the distribution of power between government levels is influenced by political and historical variables. While economic considerations are vital for achieving efficiency and equity, constitutional considerations are crucial for determining functions and responsibilities and safeguarding the distribution of power consistent with federalism principles. Therefore, this study begins by questioning the best allocation of spending responsibilities in light of economic and constitutional considerations, and what methods can be used to solve conflicts that arise in government financial relationships. We assume that economic considerations alone are not enough to design the financial system, especially in federal countries. While they theoretically explain what needs to be done to achieve economic equity and efficiency, constitutional considerations explain the types of constitutions in terms of details of power distribution in general, including financial matters and functional responsibilities for both central and regional governments. We concluded that there is no one-size-fits-all approach for all federal countries to distribute powers, as federal states operate in different political and historical settings, and the nature of intergovernmental fiscal relations are constantly changing.

Using long-term data from a whole ecosystem warming experiment to identify best spring and autumn phenology models.

Predicting vegetation phenology in response to changing environmental factors is key in understanding feedbacks between the biosphere and the climate system. Experimental approaches extending the temperature range beyond historic climate variability provide a unique opportunity to identify model structures that are best suited to predicting phenological changes under future climate scenarios. Here, we model spring and autumn phenological transition dates obtained from digital repeat photography in a boreal Picea-Sphagnum bog in response to a gradient of whole ecosystem warming manipulations of up to +9°C, using five years of observational data. In spring, seven equally best-performing models for Larix utilized the accumulation of growing degree days as a common driver for temperature forcing. For Picea, the best two models were sequential models requiring winter chilling before spring forcing temperature is accumulated. In shrub, parallel models with chilling and forcing requirements occurring simultaneously were identified as the best models. Autumn models were substantially improved when a CO2 parameter was included. Overall, the combination of experimental manipulations and multiple years of observations combined with variation in weather provided the framework to rule out a large number of candidate models and to identify best spring and autumn models for each plant functional type.

Past and future rainfall change in sub-regions of Victoria, Australia

We examine rainfall variability and change in three sub-regions of the state of Victoria in Australia: the Murray Basin Victoria (MBVic), southeast Victoria (SEVic), and southwest Victoria (SWVic). These sub-regions represent three different hydrological super-catchments over Victoria and received average cool season rainfall for the 1997–2018 period, about 15%, 11%, and 8% less, respectively, than the 1900–1959 average. All three observed declines are shown to be very unusual in terms of historical variability. On analysing CMIP5 models under different forcing conditions (preindustrial, historical-all, historical-GHGs-only, historical-natural-only, RCP2.6, RCP4.5, and RCP8.5), we estimate that external forcing caused 30% of the observed drying in SWVic, 18% in MBVic, and 17% in SEVic. The external forcing contributions to the observed trend for the 1900–2018 period are estimated to be 56%, 17%, and 24% for SWVic, MBVic, and SEVic, respectively. Taken at face value, these figures suggest that only the 1900–2018 trend in SWVic was dominated by external forcing. Nearly all models underestimate the magnitude of the observed drying. This arises because models underestimate the magnitude of decadal variability, and because models might also underestimate externally forced drying, and/or the contribution of internal variability in the real world to the observed event was unusually large. By 2037, approximately 90% of the models simulate drying in SWVic, even under a low emissions scenario. Under a high emission scenario, the anthropogenically forced drying towards the late twenty-first century is so large in all three sub-regions that internal variability appears too small to offset it.

An Improved Sap Flow Prediction Model Based on CNN-GRU-BiLSTM and Factor Analysis of Historical Environmental Variables

Sap flow is widely used to estimate the transpiration and water consumption of canopies and to manage water resources. In this paper, an improved time series prediction model was proposed by integrating three basic networks—CNN, GRU and BiLSTM—to assess sap flow with historical environment variables. A dataset with 17,569 records of each, including 9 environment variables and 1 sap flow, was applied from a public database of SAPFLUXNET. After normalization, the environment variables were analyzed and composed with the factor analysis method. After the CNN-GRU-BiLSTM structure was designed, N records of three main factors were computed from environment variables, which were measured at N previous moments, and the sap flow was measured at the current moment, and they were applied for each training, validation, and testing cycle. To improve and compare the CNN-GRU-BiLSTM-based model, nine other models, using the methods of multiple linear regression, support vector regression, random forest, LSTM, GRU, BiLSTM, CNN-GRU, CNN-BiLSTM, and CNN-GRU-LSTM, were constructed in this study, respectively. Results show that the performance of the CNN-GRU-BiLSTM-based model has more accuracy than the other nine models we built in this paper, with the mean absolute error, mean squared error, mean absolute percentage error, and coefficient of determination (R2) being 0.0410, 0.0029, 0.2708 and 0.9329, respectively. Furthermore, for a comparison of the descending dimension method of factor analysis, principal component analysis (PCA) and singular value decomposition (SVD) methods were applied and compared, respectively. Results show that the performance of the factor analysis-based model is better than the PCA- or SVD-based model, with the R2 results of the factor analysis-based model being higher than the PCA- and SVD-based models by 5.06% and 10.63%, respectively. This study indicates that the CNN-GRU-BiLSTM-based sap flow prediction model established with a factor analysis of historical environmental variables has optimistic applications for analyzing the transpiration of trees and evaluating water consumption.

Evidence of fruit syndromes in the recently diverged wild tomato clade opens new possibilities for the study of fleshy fruit evolution

Societal Impact StatementFleshy fruits provide humans with many flavorful and nutritious crops. Understanding the diversity of these plants is fundamental to managing agriculture and food security in a changing world. This study surveyed fruit trait variation across species of tomato wild relatives and explored associations among color, size, shape, sugars, and acids. These wild tomato species native to South America can be interbred with the economically important cultivated tomato. Beyond its application to tomatoes, deepening our knowledge of how fruit traits evolve together is valuable to crop improvement efforts aimed at breeding more nutritious and appealing varieties of fruits.Summary Fleshy fruits display a striking diversity of traits, many of which are important for agriculture. The evolutionary drivers of this variation are not well understood, and most studies have relied on variation found in the wild. Few studies have explored this question on a fine‐grained scale with a group of recently diverged species while controlling for environmental effects. We developed the tomato clade as a novel system for fruit trait evolution research by presenting the first common garden‐based systematic survey of variation and phylogenetic signal in color, nutrition, and morphology traits across all 13 species of tomato wild relatives (Solanum sect. Lycopersicon). We laid the groundwork for further testing of potential evolutionary drivers by assessing patterns of clustering and correlation among disperser‐relevant fruit traits as well as historical climate variables. We found evidence of two distinct clusters of associated fruit traits defined by color, sugar type, and malic acid concentration. We also observed correlations between a fruit's external appearance and internal nutrient content that could function as honest signals to dispersers. Analyses of historical climate and soil variables revealed an association between red/orange/yellow fruits and high annual average temperature. Our results establish the tomato clade as a promising system for testing hypotheses on the drivers of divergence behind early‐stage fleshy fruit evolution, particularly selective pressure from frugivores.

Two-century sediment records of atmospheric mercury variations in North China and their relations with regional and global emissions.

Sedimentary mercury (Hg) records from remote areas are significant for revealing historical variations of regional Hg and understanding the influence of regional and global Hg emissions. In this study, sediment cores were retrieved from two subalpine lakes in Shanxi Province in North China and employed to reconstruct atmospheric Hg variations over the last two centuries. The two records show similar anthropogenic Hg fluxes and evolution trends, corresponding with that they were affected mainly by regional atmospheric Hg deposition. Before ~1950, the records show negligible Hg pollution signals. Atmospheric Hg in the region had increased rapidly since the 1950s, lagged more than a half-century compared to the global Hg. This indicates that they were seldom affected by Hg emissions dominated by Europe and North America after the industrial revolution. The Hg increases since the 1950s in the two records corresponded well with rapid industrial developments in and around Shanxi Province after the founding of the China, implying the dominant contribution of domestic Hg emissions. By comparing other Hg records, we find that widespread increases in atmospheric Hg in China likely occurred post ~1950. This study rouses to re-examine historical variations in atmospheric Hg at various settings, which is significant to understanding global Hg cycling in the industrial era.

DOCU-CLIM: A global documentary climate dataset for climate reconstructions

Documentary climate data describe evidence of past climate arising from predominantly written historical documents such as diaries, chronicles, newspapers, or logbooks. Over the past decades, historians and climatologists have generated numerous document-based time series of local and regional climates. However, a global dataset of documentary climate time series has never been compiled, and documentary data are rarely used in large-scale climate reconstructions. Here, we present the first global multi-variable collection of documentary climate records. The dataset DOCU-CLIM comprises 621 time series (both published and hitherto unpublished) providing information on historical variations in temperature, precipitation, and wind regime. The series are evaluated by formulating proxy forward models (i.e., predicting the documentary observations from climate fields) in an overlapping period. Results show strong correlations, particularly for the temperature-sensitive series. Correlations are somewhat lower for precipitation-sensitive series. Overall, we ascribe considerable potential to documentary records as climate data, especially in regions and seasons not well represented by early instrumental data and palaeoclimate proxies.

Historical pricing variability in immediate and deferred income annuities

Risk Management and Insurance ReviewEarly View DATA INSIGHT Historical pricing variability in immediate and deferred income annuities David Blanchett, Corresponding Author David Blanchett [email protected] orcid.org/0000-0002-8288-0122 Retirement Research for PGIM DC Solutions, Newark, New Jersey Correspondence David Blanchett, Retirement Research for PGIM DC Solutions, Newark, NJ. Email: [email protected]Search for more papers by this authorBranislav Nikolic, Branislav Nikolic Insurance at the Index Standard, Toronto, CanadaSearch for more papers by this author David Blanchett, Corresponding Author David Blanchett [email protected] orcid.org/0000-0002-8288-0122 Retirement Research for PGIM DC Solutions, Newark, New Jersey Correspondence David Blanchett, Retirement Research for PGIM DC Solutions, Newark, NJ. Email: [email protected]Search for more papers by this authorBranislav Nikolic, Branislav Nikolic Insurance at the Index Standard, Toronto, CanadaSearch for more papers by this author First published: 22 June 2023 https://doi.org/10.1111/rmir.12244Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL REFERENCES Blanchett, D., Finke, M., & Nikolic, B. (2021). How competitive are income annuity providers over time? Risk Management and Insurance Review, 24(no. 2), 207– 214. CANNEX. 2022. “CANNEX Survey Experience: January 1, 2021 to December 31, 2021.” White Paper. Charupat, N., Kamstra, M. J., & Milevsky, M. A. (2016). The sluggish and asymmetric reaction of life annuity prices to changes in interest rates. Journal of Risk and Insurance, 83(no. 3), 519– 555. Friedman, B. M., & Warshawsky, M. J. (1990). The cost of annuities: Implications for saving behavior and bequests. The Quarterly Journal of Economics, 105, 135– 154. Habib, F., Huang, H., Mauskopf, A., Nikolic, B., & Salisbury, T. S. (2020). Optimal allocation to deferred income annuities. Insurance: Mathematics and Economics, 90, 94– 104. James, M. (1947). The Metropolitan Life: A Study in Business Growth. Viking. Milevsky, M. A. (2006). The Calculus of Retirement Income: Financial Models for Pension Annuities and Life Insurance. Cambridge University Press. Milevsky, M. A. (2005). Real longevity insurance with a deductible: Introduction to advanced-life delayed annuities (ALDA). North American Actuarial Journal, 9(no. 4), 109– 122. Poterba, J., & Solomon, A. (2021). Discount Rates, Mortality Projections, and Money's Worth Calculations for US Individual Annuities. No. w28557 National Bureau of Economic Research. Poterba, J. M., 1997, “The History of Annuities in the US.” Working paper 6001, National Bureau of Economic Research. Early ViewOnline Version of Record before inclusion in an issue ReferencesRelatedInformation

Inherited anthropogenic disturbance and decadal sediment dynamics in a mountain fluvial system: The case of the Marecchia River canyon, Northern Apennines

We evaluate decadal coarse sediment dynamics along the Marecchia River of the Northern Apennines, a fluvial system with a history of gravel mining that led to the incision of a 6-km-long canyon. To this purpose, we subdivided the river into 21 reaches, seen as sediment reservoirs, to examine (1) historical variations in active channel width (1955−2019) in conjunction with (2) change in alluvial sediment storage (2009−2019), by differencing two sequential LiDAR digital elevation models (DEMs) within the active channel footprint. Combined examination of lateral (widening or narrowing) and vertical (aggradation or degradation) channel changes allowed the identification of composite styles of reservoir adjustment, as well as the refinement of geomorphic inference solely based on changes in active channel width. In particular, we find that different styles of decadal adjustment (1) are compatible with supply- and transport-limited conditions, as constrained by degree of confinement, stream channel slope, and active channel width; and (2) indicate different stages of evolution at reservoirs located upstream and downstream of the canyon head (dynamic equilibrium vs. transient response). The persistence of this geomorphic divide is supported over historical time scales by distinctive trends in planform channel changes, suggesting that sedimentary signal propagation downstream becomes abruptly interrupted at the canyon head. Over this 10-year natural experiment, the spatial pattern of erosion along the canyon exemplifies a striking case of transient response to anthropogenic forcing, where decadal topographic change, modulated by varying styles of hillslope-channel coupling, declines nonlinearly downstream. Depth of incision along the canyon increases progressively upstream, suggesting that the canyon head has been evolving toward a more unstable configuration with no significant change in sediment supply. This tendency, which points to a possible runaway style of development as bedload wearing on weak pelitic side walls continues, may hold basic implications for our understanding of channel incision into bedrock and strath terrace formation.

The climatic risk of Amazonian protected areas is driven by climate velocity until 2050.

Changes in species distribution in response to climate change might challenge the territorial boundaries of protected areas. Amazonia is one of the global regions most at risk of developing long distances between current and future analogous climates and the emergence of climate conditions without analogs in the past. As a result, species present within the network of Protected Areas (PAs) of Amazonia may be threatened throughout the 21st century. In this study, we investigated climate velocity based on future and past climate-analogs using forward and backward directions in the network of PAs of Amazonia, in order to assess the climatic risk of these areas to climate change and verify their effectiveness in maintaining the current climate conditions. Using current (1970-2000) and future (2041-2060) average annual air temperature and precipitation data with a resolution of 10 km, climate velocities across the entire Amazon biome and average climate velocities of PAs and Indigenous Lands (ILs) were evaluated. The results show that the effects of backward velocity will be greater than that of forward velocity in the Amazon biome. However, the PA network will be less exposed to backward velocity impacts than unprotected areas (UAs)-emphasizing the importance of these areas as a conservation tool. In contrast, for the forward velocity impacts, the PA network will be slightly more exposed than UAs-indicating that the current spatial arrangement of the PA network is still not the most suitable to minimize impacts of a possible climate redistribution. In addition, a large extent of no-analog climates for backward velocities was found in central Amazonia, indicating that high temperatures and changes in precipitation patterns in this region will surpass the historical variability of the entire biome, making it a potentially isolated and unsuitable climatic envelope for species in the future. Most of the no-analog climates are in PAs, however the climate risks in ILs should also be highlighted since they presented higher climate velocities than PAs in both metrics. Our projections contrast with the median latitudinal migration rate of 2 km/year observed in most ecosystems and taxonomic groups studied so far and suggest the need for median migration rates of 7.6 km/year. Thus, despite the important role of PAs and ILs as conservation tools, they are not immune to the effects of climate change and new management strategies, specific to each area and that allow adaptation to global changes, will be necessary.

Does CMIP6 inspire more confidence in projecting precipitation over China?

AbstractDespite significant advancements in recent versions of general circulation models (GCMs), uncertainties persist in simulations of both historical and future precipitation. Notably, disparities exist between the simulated precipitation before 2015 and the projected precipitation in Coupled Model Intercomparison Project Phase 6 (CMIP6) models. In this study, the accuracy of projected precipitation in 12 CMIP6 models was evaluated before and after applying SD and EDCDFm methods, by comparing with observed precipitation data during 2015–2020. This study aims to address the gap in the comprehensive evaluation of projected precipitation against observational data. The results of the study showed that: (1) Downscaling and bias correction improved the skill of CMIP6 models in simulating spatial distribution of precipitation during 1961–2014, especially in east China. However, bias‐corrected projected precipitation during 2015–2020 exhibited a dry bias over most of China. (2) Bias correction improved the capability of CMIP6 models in simulating historical monthly variations in precipitation, but did not address the issue of projected precipitation following the simulated seasonal cycles. (3) The improvement of projected precipitation after bias correction was limited during 2015–2020, and for CanESM5, IPSL‐CM6A‐LR, and MIROC6 models, bias correction even exacerbated the bias of projected precipitation over the Song–Liao River, Yangtze River, and Southeast River basins. (4) Bias‐corrected CMIP6 models generally underestimated the increase in precipitation after 2015, but projected precipitation over China was still expected to increase during 2015–2099 after bias correction. These findings emphasize the need for more precise strategic suggestions to improve the projection of precipitation.

Mapping a Decade of Smart Homes for the Elderly in Web of Science: A Scientometric Review in CiteSpace

Challenges caused by the care of the ageing population in many countries are becoming increasingly severe. However, high expenditures on healthcare services and the cost of infrastructure construction will be an unbearable burden for both the government and individuals. Due to its security, convenience, and lower prices compared with traditional medical care, smart home technology, which includes information and communication technologies (ICTs), artificial intelligence (AI), and the Internet of Things (IoT), can reduce the care burden. While smart home studies targeting older adults have increased, systematic analysis of these studies is lacking. CiteSpace enables rapid clustering and visualisation of the literature using scientific diagrams, exhibiting the results more comprehensibly. This analysis of academic research published within the last decade (from 2012 to 2023) through a scientometric approach can help to understand the historical variations, the latest technologies and emerging trends, and the research clusters that have emerged related to the study of smart homes for the elderly (SHFTE). The study results showed that recent research mainly centres on IoT for home automation and home-based healthcare, including wearable device applications and information security analysis. Research trends regarding SHFTE have focused primarily on developing and updating smart technologies based on the IoT, sensors, and related home monitoring. Therefore, greater emphasis must be placed on connecting smart homes and intelligent buildings with communities and societies, developing the potential of smart communities, and investigating the application of smart integration to the home and community in cities.

The Correlation of Morality and Law in the Works of I. A. Ilyin and G. F. Shershenevich: Comparison of Natural Law and Normative Approaches

The article substantiates the need to address the political and legal heritage of pre-revolutionary Russian legal thought and offers an analysis of the scientific heritage of the classics of domestic political and legal thought I. A. Ilyin and G. F. Shershenevich on the relationship between morality and law. The concepts of social norms, their purpose and place in the system of social regulation are investigated. The social nature of morality, its regulatory function and historical variability, means of influencing persons who do not comply with the norms of morality are noted. The difference between legal regulation and moral regulation is carried out. The social utility of morality, the concept of moral behavior and its motives are investigated. In the context of understanding the law, attention is focused on its coercive nature and types of legal sanctions. Within the framework of the close interaction of morality and law, it is emphasized that giving a moral norm a legal sanction gives this norm a mixed character — ethical and legal. It is noted that the requirements of morality and law in some cases may contradict each other.

Seagrass meadow stability and composition influence carbon storage

ContextSeagrass ecosystems are lauded for storing organic carbon in underlying sediments, but storage is highly variable, even at relatively small spatial scales. While environmental setting and seagrass cover are known drivers of carbon storage capacity, it is unclear how other seagrass features such as species composition influence carbon storage, and whether historical vs. contemporary features are better predictors of storage.ObjectivesWe examined the influence of historical and contemporary seagrass variables on surface (0–10 cm) sediment organic carbon storage at the meadow-scale (~ 25 km2), in addition to the influence of environmental drivers. Our study area was located within a subtropical mixed-species seagrass meadow along a low-energy coastline in the northeastern Gulf of Mexico (Cedar Key, Florida, USA).MethodsWe derived historical metrics of seagrass cover and composition from 14-year seagrass monitoring datasets and measured surface sediment carbon densities and grain size, contemporary seagrass biomass and species composition, as well as environmental characteristics related to hydrology and physical disturbance (i.e., relative exposure, elevation, and distance to navigation channels). We assessed bivariate relationships between predictor variables and surface carbon densities with linear regression analyses and used path analysis to assess hypothesized relationships between a subset of predictor variables and carbon densities.ResultsWhile low relative to global values, surface carbon densities in Cedar Key seagrass meadows varied by an order of magnitude. Sediment grain size was strongly related to carbon densities, but environmental variables had only indirect effects on carbon densities. Historical seagrass cover, variability in cover, and species diversity were generally better predictors of storage than contemporary variables. Historical and contemporary species identity–specifically the presence of Thalassia testudinum–were also significant drivers of storage.ConclusionsIn Cedar Key, historically diverse and persistent seagrass meadows dominated by late-successional species contained the largest surface carbon stores. Our results highlight the importance of site history in terms of meadow stability (inversely measured as variability in cover) as well as species identity and diversity in enhancing surface carbon storage. The environmental variables we examined had comparatively weak effects on carbon densities, however, relative exposure and elevation may not be the most relevant hydrological drivers of carbon storage at the meadow scale. Together, these findings suggest that drivers of seagrass meadow carbon storage are context and scale dependent.

Drift of Earth's Pole Confirms Groundwater Depletion as a Significant Contributor to Global Sea Level Rise 1993–2010

AbstractClimate model estimates show significant groundwater depletion during the 20th century, consistent with global mean sea level (GMSL) budget analysis. However, prior to the Argo float era, in the early 2000’s, there is little information about steric sea level contributions to GMSL, making the role of groundwater depletion in this period less certain. We show that a useful constraint is found in observed polar motion (PM). In the period 1993–2010, we find that predicted PM excitation trends estimated from various sources of surface mass loads and the estimated glacial isostatic adjustment agree very well with the observed. Among many contributors to the PM excitation trend, groundwater storage changes are estimated to be the second largest (4.36 cm/yr) toward 64.16°E. Neglecting groundwater effects, the predicted trend differs significantly from the observed. PM observations may also provide a tool for studying historical continental scale water storage variations.

A Multistep Interval Prediction Method Combining Environmental Variables and Attention Mechanism for Egg Production Rate

The egg production rate is a crucial metric in animal breeding, subject to biological and environmental influences and exhibits characteristics of small sample sizes and non-linearity. Currently, egg production rate prediction research predominantly focuses on single-step point prediction, lacking multistep and interval prediction exploration. To bridge these gaps, this study proposes a recursive, multistep interval prediction method for egg production rates, integrating environmental variables and attention mechanisms. Initially, this study employed three gradient boosting tree models (XGBoost, LightGBM, CatBoost) and the recursive feature elimination (RFE) method to select critical environmental variables and reduce data dimensionality. Subsequently, by scaling the time scale of important environmental variables and utilizing the variational modal decomposition improved by the grey wolf optimization (GWO-VMD) method for time-series decomposition, the volume of important environmental variable data is augmented and its complexity is reduced. Applying the long short-term memory (LSTM) neural network to obtain direct multistep predictions on IMFs, the predicted outcomes are averaged daily to yield the environmental variables for the upcoming two days. Finally, a multistep interval prediction model based on Seq2seq-Attention and Gaussian distribution is proposed in this study, and parameter optimization is carried out using the multi-objective grey wolf optimization algorithm (MOGWO). By inputting the historical egg production rate data and environmental variables into the proposed model, it is possible to achieve multistep point and interval prediction of egg production rates. This method was applied to analyze a dataset of egg production rates of waterfowl. The study demonstrated the feasibility of the recursive multistep prediction approach combined with environmental variables and guides egg production estimation and environmental regulation in animal husbandry.

Ancient Understanding of Time and the Background of Contemporary Historicism

Contemporary changes in historical culture associated with various states of modernity actualize the problem of the foundations and prerequisites of historicism as a principle of thinking characteristic of modern societies. The ancient historicism background consists primarily in the advanced concepts of time and eternity, which contain the potential variability in the understanding of historicity in modern philosophy and culture. At the same time, the problem of the historical variability of the world remained on the periphery of ancient philosophy and culture, and classical historicism, which was established in the second half of the 18th century, was based on the rejection of some aspects of the ancient heritage. In opposing being and becoming, ancient philosophy preferred being, which was also manifested in the preference for truth over time, for one over multiple. Classical historicism of modern times is focused on the idea of becoming, which in a new way reveals the contradictions between truth and time, one and multiple. Relativism and plurality are becoming features of modern transformations of historicism, in which the structures of time are preserved, dating back to the ancient concepts of chronos, kairos, eon, etc. Of particular interest are modern ideas about time, which go back to the ancient concept of objectified chronological time and its correlation with other forms of time conceptualization. In the historical consciousness of modern times, the ancient concepts of time were transformed under the influence of the prophetic sense of time, characteristic of the biblical tradition, in which the historical process is considered in the context of the gradual revelation of the original intention and meaning of history.