Variability In Space Research Articles

Estimating solute travel times from time series of nitrate concentration in groundwater: Application to a small agricultural catchment in Brittany, France

Stream flow and concentration dynamics are usually supposed to integrate the diverse hydrological and biogeochemical processes occurring within catchments and their variability in space and time. Proxies like transit times and young water fractions are often used to understand this variability. However, this procedure might not be suitable in catchments with ephemeral streams. The objective of this paper is to test the hypothesis that in catchments where groundwater flow is the main source of water output, solute travel times can be inferred from the monitored groundwater levels and solute concentration time series of piezometer networks. We used data from a well-studied small agricultural catchment in Brittany, belonging to the French network of Critical Zone Observatories. The data set includes long-term nitrate concentration time-series measured both at the stream outlet and the network of piezometers. We applied a parsimonious, conceptual dual-permeability mixing modelto calibrate our dataset and found that the nitrate travel times estimated in mid to upslope piezometers were consistently higher than the one at the stream outlet. We further observed an asynchronicity in seasonal concentration-discharge dynamics between the piezometers and the stream. We hypothesized that either due to riparian denitrification and uptake by vegetation, a pronounced seasonality is being generated which is making our model underestimate the nitrate travel times at the stream, or the piezometers are acting as proxies to the slower conceptual store of our mixing model, and shallow subsurface flow or some hydrologically significant heterogeneities are contributing to the faster route which is not tapped into by the piezometer network. Latter hypothesis is further supported by the fact that nitrate travel velocity along two different transects are in agreement with the slower conceptual store of our model. Nevertheless, we established that to specifically estimate the groundwater travel time of a catchment, a piezometer free from riparian influence alongside a stream is very beneficial.

TID evaluation based on variabilities of space radiation and device failure dose in typical navigation satellite orbits

Navigation satellites mainly operate in Medium Earth Orbit (MEO), Geostationary Earth Orbit (GEO), and Inclined Geosynchronous Satellite Orbit (IGSO). These orbits lie in or repeatedly cross the outer Van Allen belt of Earth. With large uncertainty, the radiation in these orbits mainly comes from electrons trapped in the outer radiation belt and solar energetic protons. The accurate design of the radiation shielding structure plays an important role in improving the efficiency of satellites. We introduce a method that incorporates the radiation variability in space and failure dose uncertainty of devices to evaluate the survival probability of devices caused by the Total Ionizing Dose (TID) effect. After fitting the failure dose data of operational amplifier TL084 by the Weibull distribution, we calculate the Confidence Levels (CLs) of all possible parameters of the distribution. Based on these parameters and the cumulative probability distribution of TID from space, we evaluate the effects of shielding thickness and mission duration on TL084's failure possibility at different CLs in MEO/GEO/IGSO. Furthermore, the required shielding thickness and the expected survival duration to ensure that TL084 could operate safely at specific CL are also investigated. By using this method, we could approach a balance among the device's ability, the shielding thickness, the expected duration of safe operation, and the confidence level of the design.

Spatial and temporal variations of the flow characteristics at a tidal stream power site: A high-resolution numerical study

The upcoming commercial development of tidal stream power requires a profound knowledge of tidal streams. In this article, the spatial and temporal variations of the flow characteristics are investigated through numerical simulations, at fine spatial and temporal resolutions. The study highlights the necessity of local site characterisation prior to turbine installation, due to the high spatial variability of the flow characteristics over distances of less than 100 m. The high variability in space and time of the flow characteristics at the scale of a turbine and its impact on the blade angle of attack underscore the relevance of a good blade pitch control strategy. The study of extreme events in term of maximal flow velocity and variations in the flow direction gives insight for the structural dimensioning of future tidal stream power devices.

Classification of white matter lesions and characteristics of small vessel disease markers.

Radiological markers for cerebral small vessel disease (SVD) may have different biological underpinnings in their development. We attempted to categorize SVD burden by integrating white matter signal abnormalities (WMSA) features and secondary presence of lacunes, microbleeds, and enlarged perivascular spaces. Data were acquired from 610 older adults (aged > 40 years) who underwent brain magnetic resonance imaging exam as part of a health checkup. The WMSA were classified individually by the number and size of non-contiguous lesions, distribution, and contrast. Age-detrended lacunes, microbleeds, and enlarged perivascular space were quantified to further categorize individuals. Clinical and laboratory values were compared across the individual classes. Class I was characterized by multiple, small, deep WMSA but a low burden of lacunes and microbleeds; class II had large periventricular WMSA and a high burden of lacunes and microbleeds; and class III had limited juxtaventricular WMSA and lacked lacunes and microbleeds. Class II was associated with older age, diabetes, and a relatively higher neutrophil-to-lymphocyte ratio. Smoking and higher uric acid levels were associated with an increased risk of class I. The heterogeneity of SVD was categorized into three classes with distinct clinical correlates. This categorization will improve our understanding of SVD pathophysiology, risk stratification, and outcome prediction. • Classification of white matter signal abnormality (WMSA) features was associated with different characteristic of lacunes, microbleeds, and enlarged perivascular space and clinical variability. • Class I was characterized by multiple, small, deep WMSA but a low burden of lacunes and microbleeds. Class II had large periventricular WMSA and a high burden of lacunes and microbleeds. Class III had limited juxtaventricular WMSA and lacked lacunes and microbleeds. • Class II was associated with older age, diabetes, and higher neutrophil-to-lymphocyte ratio. Smoking and higher uric acid levels were associated with an increased risk of class I.

Space and Time Variability of Detachment‐ Versus Ramp‐Dominated Thrusting: Insights From the Outer Albanides

AbstractDespite their markedly different structural setting, the northern and southern outer Albanides share a common tectonic evolution from detachment‐dominated to ramp‐dominated, basement‐involved thrusting. The former process (mainly Oligocene to Miocene) is essentially related with the occurrence of a thick décollement level represented by Triassic evaporites, while the latter involves basement ramps splaying out from a middle crustal décollement. As this weak crustal layer is inherited from the Mesozoic rifting stage, the original continental margin architecture is interpreted to strongly influence subsequent convergent deformation. The profoundly different nature of the two dominant décollements in the study area controlled the structural style of the fold and thrust belt. The decoupling capacity of the upper décollement is strongly dependent on the thickness of the Triassic evaporites. Where this is significant (≫1 km; southern outer Albanides), the occurrence of such a thick incompetent layer at the base of competent carbonate units favored the development of break‐thrust folds and imbrication of the sedimentary cover. Fold and thrust belt propagation was instead hindered where original stratigraphic variations resulted in a reduced thickness (≤1 km) of Triassic evaporites. On the other hand, the deeper middle crustal décollement is controlled by basement rheology. Its reactivation during plate convergence was assisted by collision‐related thermal weakening of the crust. This process governed late‐stage (<5 Ma) crustal‐scale tectonic inversion and plays a major role in controlling present‐day seismicity.

A Prediction Model For Lightning-Induced Overvoltages Over Lossy Ground Using Gaussian Process Regression

The accurate assessment of lightning-induced over-voltages is essential for proper insulation coordination studies. In this paper, a novel machine learning based Gaussian process regression model is developed for the prediction of lightning-induced over-voltages considering wide range of ground resistivity and permittivity. The lightning-induced over-voltages have been computed using two-dimensional finite-difference time-domain technique associated with Agrawal field to line coupling model. To account for the input space variability, seven predictor variables namely: resistivity, permittivity, return stroke velocity, distance from flashpoint, return stroke peak current, front-time, and height of an overhead line are considered to determine the response variable, that is, lightning-induced over-voltages. Accordingly, the training of the Gaussian process regression model is carried out using lightning-induced over-voltages obtained from two-dimensional finite-difference time-domain technique for both first and the subsequent strokes. The estimation accuracy of model is appraised using root mean squared error indicating that the exponential kernel function has the least error than other kernel types for describing the covariance. The predictive performance is evaluated by corroborating the predictions from the model against the random test cases generated from two-dimensional finite-difference time-domain technique. The predicted results showed a good agreement with those obtained from finite-difference time-domain technique.

Topological optimization applied to a variable density and conductivity model of pollution in porous media

AbstractThis article deals with modeling and numerical study of pollutants transfer in porous media by topological optimization. Indeed we perform the modeling of pollution in porous media in non‐permanent cases by assuming the variability or not of some parameters such as the conductivity and the density. The model of pollutants transfer obtained in the case when the conductivity and the density are constant is similar to meadows of few coefficients to the one obtained by varying (with respect to the space) only the conductivity. By taking into account the space variability of density, conductivity, and diffusion under some assumptions we obtain a more realistic model of pollutants transfer. Topological optimization applied to these models allows reaching numerically the optimal design of a least squared functional. In fact, topological derivatives are used as descent direction and permit to creation of circular or cylindrical holes in order to decrease the considered cost function. Numerical results obtained are presented for Neumann and Dirichlet conditions on the boundary of the holes for 2 and 3 dimensions in nonpermanent cases of pollutants transfer.

The probability‐based granular field of vegetated soils

AbstractSoils in vegetation‐covered areas are of high variability in space and time, and the variability is crucial for hydro‐geophysical processes at small and large scales. Conventionally, the spatial heterogeneity at large scale is visualized as a regional division map of soil properties by extrapolating sample measurements. No formalized method is available for assigning parameters for soils at the resolution of a small grid cell. This study formulates a method of establishing parameter space for vegetated soil by a single index (μ) derived from the unified grain size distribution (GSD). The index μ varies in space as a random variable and defines soil as a granular field. The μ‐division represents the concentration of fine grains in response to root–soil interactions. Coupling μ‐division with moisture distribution suggests that the gradient of μ plays a potential role in rooted soil hydraulics. It is further found that μ satisfies the Weibull distribution, which makes it possible to establish the μ‐field for a soil space at large scale using the random dataset of μ. A case study is conducted in two vegetated slopes based on high‐resolution digital elevation models (DEM) derived from unmanned aerial vehicle survey to create the field and illustrate its implications in morphology and hydrology. It is expected that the μ‐field may derive parameter fields of various soil properties as functions of the GSD parameters and thus equip DEM with a complete dataset of soil. The paradigm proposed in the study fills the gap of establishing high‐resolution data space for soil at large scale for dynamics of surface processes.

Isotopic fingerprinting of dual monsoon moisture sources, evapotranspiration process and microclimate manifestation over the tropical rainforest region, western part of the Western Ghats, India

The changes in precipitation pattern provide an understanding on the hydroclimatic response to global warming during the Anthropocene. The present study investigates sources of precipitation moisture for the Indian Monsoon and the local environmental mechanisms controlling its distribution over the southwest coast of India. This is achieved by the characterization of stable isotope ratios of oxygen (δ18O) and hydrogen (δ2H) in rainwater samples collected from a high humid tropical setting (Swarna-Madisal river basin) of the Western Ghats, South India and another station further south (Bakrabail, southern edge of Nethravati river basin). This study contributes to the detailed investigation on rainwater isotopic composition and microclimate characteristics which is lacking in the humid west coast region. The rainwater isotopic composition of coast was close to that of the Arabian Sea water and reflected the first condensate of vapours which were originally formed under fast evaporation at the nearby ocean. In inland location, the higher d-excess values reflect continental moisture recycling. Evapotranspiration has led to higher kinetic fractionation effect in the inland region. The isotopic storm effect during winter monsoon season suggested the rain distribution from saturated air masses formed under deep convective effect in the Bay of Bengal. The overall local meteoric water line (LMWL) in the Swarna-Madisal basin was found to be δ2H = {(7.2 × δ18O) + 7.5}, R2 = 0.98. Further south, the LMWL of Bakrabail was, δ2H = {(8.19 × δ18O) + 16.1}, R2 = 0.98 for annual observation and displayed minimal variability for inter-seasonal slopes (7.73 for summer monsoon, 8.48 for winter monsoon and 8.36 for pre-monsoon) and intercepts (15.6 for summer monsoon, 17.8 for winter monsoon and 15.5 for pre-monsoon). In regions of vegetation dominance and humid climate, the prevailing local air mass masked the rain-out effect of marine air mass as well as the amount effect which support microclimatic settings at the local precipitation sites in southwest India. The time and space variability of regional moisture circulation in controlling atmospheric water balance has been deduced in this study. Thus, the high efficacy of stable isotopes in tracing the manifestation of microclimate in the humid tropics has been demonstrated.

Литологические и геохимические особенности нижнетриасовых резервуаров на севере вала Сорокина (Тимано-Печорская нефтегазоносная провинция)

The paper describes lithological and geochemical features of the Lower Triassic sandstones from the far north of Timan-Pechora oil and gas-bearing province. These sandstones chemically coincide to typical graywackes.
 We discuss how sedimentation environments and diagenesis control the local heterogeneity of cementation, variability of void space and the potential oil content. 
 Tectonic conditions are one of the provenance factors, the figurative points of the composition of sandstones on the diagrams fall into the field of the passive continental margin. The position of sandstone points on the diagrams and low values of the hydrolyzate module indicate the formation of deposits in an arid climate, which does not contradict to geological data.

Primary drivers of multidecadal spatial and temporal patterns of shoreline change derived from optical satellite imagery

Understanding and predicting shoreline change along sandy coasts requires continuous (in both time and space) long-term (decades) shoreline data at good spatial (e.g. 100 s of metres) and temporal (e.g. months) resolution. Publicly available satellite imagery can now provide such time series. However, satellite-derived shorelines (SDS) are associated with uncertainties, particularly at high-energy meso-macrotidal coasts, which challenge the assessment of long-term trends and interannual variability. In this paper we address the 1984–2020 time- and space-evolution of 269 km of high-energy meso-macrotidal sandy coast in southwest France using uncertain (no tide and runup correction) SDS data. The shoreline trends are validated with field data collected over the period 2008–2019. Over 1984–2020, the shoreline eroded by 0.55 m/yr with maximum erosion (accretion) reaching 15.61 m/yr (6.94 m/yr), with the largest changes observed along coasts adjacent to the inlet and estuary mouths. We show that, away from the presence of ebb-tide deltas and swash bars affecting offshore wave transformation and nearshore circulation, the long-term shoreline trend is well explained by the gradients in longshore drift computed from a regional wave hindcast and an empirical longshore transport formula. By averaging the yearly SDS along the entire coastline, we find that interannual shoreline variability is well correlated with the winter West Europe Pressure Anomaly (WEPA), which outscores the other conventional teleconnection pattern indices. WEPA even explains >80 % of the space-averaged shoreline variability over the recent period 2014–2020 when more and higher quality satellite images are available. A more local assessment of the links between climate indices and shoreline response shows that correlation with all climate indices dramatically drops downdrift of the large-scale estuary mouths and inlets. This suggests that along this 10–20 km stretch of downdrift coast, shoreline response is controlled factors internal to the estuary mouth/inlet system. The rest of the coast is mostly controlled by factors external to the system, which are primarily the variability in winter-mean wave height correlated to winter WEPA index. Overall, we demonstrate that an adapted space-averaging of uncorrected (noisy) SDS dataset can allow addressing the time- and space variability of shoreline change and their primary drivers including large-scale climate patterns of atmospheric variability. We also advocate that such SDS analysis can be performed along any coastline in the world in order to guide future model development and application.

Ground-based investigation of a directional, flexible, and wireless concentrated solar energy transmission system

Solar energy in space is more intensive and continuous compared to that on the Earth, and thus, is encouraged by governments across the world to be utilized for human beings. The continuity of the space sunlight has a great potential to overcome the bottleneck of the variability and intermittency in time and space for ground-based solar energy applications. Space solar power station (SSPS) is known as intermedia that can harvest the space solar energy and transmit it wirelessly to the end-user. However, the current wireless energy transmission via microwave or laser suffers from low energy transmission efficiency because of excessive energy conversion processes. Wireless energy transmission via sunlight without any intermediate energy conversion process was proposed previously theoretically for high energy transmission efficiency, but it also lacks practicability due to heavyweight and inflexibility. Therefore, although promising, practical sunlight-based wireless energy transmission proposals have not ever been presented. Here, through component and structure optimizations in theoretical and experimental approaches, a novel and more practical concentrated solar energy wireless transmission system that transmits the harvested sunlight via lightweight optical fibers is proposed in this paper. It uses a Fresnel lens to collect concentrated solar energy and then, the utilized optical fiber can steer the collected energy to the collimator flexibly. At last, a parallel sunlight beam can be emitted from the collimator to the target end-user. Results show that the transmitter efficiency versus optical fiber length exhibited a linear relationship from both theoretical and experimental approaches. the cloud effect harmed the energy transmission. A maximum transmitter energy transmission efficiency of 52.0% could be attained experimentally. Compared with the performance in the no-cloud condition, the gained voltage could be declined by 37% ∼ 48%. The bending of the optical fiber seemed to not affect much on the energy transmission performance, which guarantees a flexible energy transmission. Besides, the power/weight ratio was increased by 17.0% compared to its counterpart. The innovation of this paper is to reduce the gap between theoretical and practical feasibilities for the proposed system. This paper experimentally demonstrates the feasibility of a wireless concentrated solar energy transmission technology, which promotes the application of SSPS and related aerospace applications.

Changes in surface velocities over four decades on the Laurichard rock glacier (French Alps)

AbstractThe longest time series of surface velocities recorded on a rock glacier in the French Alps, covering more than three decades, has been recorded since 1983 on the Laurichard rock glacier (Ecrins range). The time signal of velocity changes is extracted from variance analyses separating time and space variabilities on the rock glacier surface to provide an average‐wide time signal. We show that changes in velocity from year to year are virtually uniform at all locations with homogeneous accelerations or decelerations on the scale of the rock glacier as a whole. The spatial structure of velocity was found to be nearly at steady state over 35 years. Nonlinear effects are located in low‐velocity areas such as the rock glacier margins where accelerations/decelerations tend to be proportional to the local velocity. Over the period of record, a long‐term trend in rock glacier acceleration was detected with a rate of +0.2 m/yr per decade. Two main phases of acceleration were identified from the mid‐1980s to 1999 and from 2010 to 2015. In between, those two periods were interrupted by a 10‐year period of almost steady‐state velocities with an abrupt deceleration from 2006 to 2009 of −0.35 m/yr. The process of internal increases in ice temperatures alone (and associated changes in creep rates) would seem insufficient to explain the long‐term rise of surface velocities and their annual variations. Changes in the liquid water are a possible contributing factor, due to the injection of seasonal water caused by melting snow cover or internal melt due to heat generated by enhanced ice creep and friction in the ice/debris mixture.

RNA Biomarker Trends across Type I and Type II Aerobic Methanotrophs in Response to Methane Oxidation Rates and Transcriptome Response to Short-Term Methane and Oxygen Limitation in Methylomicrobium album BG8.

ABSTRACTMethanotrophs, which help regulate atmospheric levels of methane, are active in diverse natural and man-made environments. This range of habitats and the feast-famine cycles seen by many environmental methanotrophs suggest that methanotrophs dynamically mediate rates of methane oxidation. Global methane budgets require ways to account for this variability in time and space. Functional gene biomarker transcripts are increasingly studied to inform the dynamics of diverse biogeochemical cycles. Previously, per-cell transcript levels of the methane oxidation biomarker pmoA were found to vary quantitatively with respect to methane oxidation rates in the model aerobic methanotroph Methylosinus trichosporium OB3b. In the present study, these trends were explored for two additional aerobic methanotroph pure cultures grown in membrane bioreactors, Methylocystis parvus OBBP and Methylomicrobium album BG8. At steady-state conditions, per-cell pmoA mRNA transcript levels strongly correlated with per-cell methane oxidation across the three methanotrophs across many orders of magnitude of activity (R2 = 0.91). The inclusion of both type I and type II aerobic methanotrophs suggests a universal trend between in situ activity level and pmoA RNA biomarker levels which can aid in improving estimates of both subsurface and atmospheric methane. Additionally, genome-wide expression data (obtained by transcriptome sequencing [RNA-seq]) were used to explore transcriptomic responses of steady-state M. album BG8 cultures to short-term CH4 and O2 limitation. These limitations induced regulation of genes involved in central carbon metabolism (including carbon storage), cell motility, and stress response.IMPORTANCE Methanotrophs are naturally occurring microorganisms capable of oxidizing methane, having an impact on global net methane emissions. Additionally, they have also gained interest for their biotechnological applications in single-cell protein production, biofuels, and bioplastics. Having better ways of measuring methanotroph activity and understanding how methanotrophs respond to changing conditions is imperative for both optimization in controlled-growth applications and understanding in situ methane oxidation rates. In this study, we explored the applicability of methane oxidation biomarkers as a universal indicator of methanotrophic activity and explored methanotroph transcriptomic response to short-term changes in substrate availability. Our results contribute to better understanding the activity of aerobic methanotrophs, their core metabolic pathways, and their stress responses.

Shade tree pattern of highland coffee plantation and coffee production in Aceh Tengah, Indonesia

Coffee is one commodity has high economics market that cultivated by farmer mainly in the high elevation area. The economics and ecological function of coffee plantations have to be worked in the area plantation, so formulation combination between coffee and forest tree is important. The research aimed to identify the tree species composition of a shade tree in a coffee plantation. Some plot sized 50 m x 50 m was distributed based on lands properties of farmers. Density, frequency, and tree spacing were measured to get basal area, relative density, relative frequency, and important value index. A more in-depth statistical analysis was performed using SPPS to determine the significance of the relationship between density and frequency with coffee productivity. The relationship between tree spacing planting, basal area, and shade trees’ density with Arabica coffee production is a strong enough relationship is the density variable. While the relationship between regular and disordered planting spacing variables with coffee production is strong. The relationship between basal area, density, and coffee production is very weak.

A conceptual model for unifying variability in space and time: Rationale, validation, and illustrative applications

With the increasing demand for customized systems and rapidly evolving technology, software engineering faces many challenges. A particular challenge is the development and maintenance of systems that are highly variable both in space (concurrent variations of the system at one point in time) and time (sequential variations of the system, due to its evolution). Recent research aims to address this challenge by managing variability in space and time simultaneously. However, this research originates from two different areas, software product line engineering and software configuration management, resulting in non-uniform terminologies and a varying understanding of concepts. These problems hamper the communication and understanding of involved concepts, as well as the development of techniques that unify variability in space and time. To tackle these problems, we performed an iterative, expert-driven analysis of existing tools from both research areas to derive a conceptual model that integrates and unifies concepts of both dimensions of variability. In this article, we first explain the construction process and present the resulting conceptual model. We validate the model and discuss its coverage and granularity with respect to established concepts of variability in space and time. Furthermore, we perform a formal concept analysis to discuss the commonalities and differences among the tools we considered. Finally, we show illustrative applications to explain how the conceptual model can be used in practice to derive conforming tools. The conceptual model unifies concepts and relations used in software product line engineering and software configuration management, provides a unified terminology and common ground for researchers and developers for comparing their works, clarifies communication, and prevents redundant developments.

Evolving software system families in space and time with feature revisions

Software companies commonly develop and maintain variants of systems, with different feature combinations for different customers. Thus, they must cope with variability in space. Software companies further must cope with variability in time, when updating system variants by revising existing software features. Inevitably, variants evolve orthogonally along these two dimensions, resulting in challenges for software maintenance. Our work addresses this challenge with ECSEST (Extraction and Composition for Systems Evolving in Space and Time), an approach for locating feature revisions and composing variants with different feature revisions. We evaluated ECSEST using feature revisions and variants from six highly configurable open source systems. To assess the correctness of our approach, we compared the artifacts of input variants with the artifacts from the corresponding composed variants based on the implementation of the extracted features. The extracted traces allowed composing variants with 99-100% precision, as well as with 97-99% average recall. Regarding the composition of variants with new configurations, our approach can combine different feature revisions with 99% precision and recall on average. Additionally, our approach retrieves hints when composing new configurations, which are useful to find artifacts that may have to be added or removed for completing a product. The hints help to understand possible feature interactions or dependencies. The average time to locate feature revisions ranged from 25 to 250 seconds, whereas the average time for composing a variant was 18 seconds. Therefore, our experiments demonstrate that ECSEST is feasible and effective.

Spatial–temporal dynamics and recovery mechanisms of dried soil layers under Robinia pseudoacacia forest based on in‐situ field data from 2017 to 2020

AbstractPlanting Robinia pseudoacacia in water‐limited regions can promote soil and water conservation and ecological service functions. However, it can cause the formation of below ground dried soil layers (DSLs), causing land degradation and tree mortality. To ascertain the spatial–temporal dynamics and recovery processes of DSLs, we monitored the deep soil water content (SWC) to a depth of 500 cm at 27 sites on a typical R. pseudoacacia forest from 2017 to 2020 and calculated the evaluation indices of DSLs based on plant‐available SWC (PASWC) and stable field capacity (SFC). Compared with PASWC‐identified DSLs, the degree of SFC‐identified DSLs was more severe, although the spatial–temporal characteristics were similar. Severe soil desiccation was identified as 79% of the 500 cm profile dried out below 101 cm. The mean thickness of DSL and mean SWC within a DSL were 396 cm and 9.0%, respectively, and the quantitative index reached Grade III (severe) DSLs. All DSL indices demonstrated weak or moderate variability in space and strong variability in time. The heterogeneity of rainfall events and microtopographic positions explain the spatial–temporal variation of DSL indices well. A heavy rainfall event (>50 mm) triggered the disappearance of DSLs at some sites, indicating the possibility of DSLs recovery based on field observations under natural condition. Microtopography (such as the swales) provides advantageous conditions to the recovery of DSLs by redistributing rainfall flow at the local scale. These results provide insights into DSLs recovery, which is useful for land development and rehabilitation in planted forests.

Spatial heterogeneity in health risks of illness-related absenteeism associated with PM2.5 exposure for elementary students

Little is known about the impact of socio-economic and environmental factors on the associations between PM2.5 exposure and health risk for elementary students. We estimated the space variability of effects of PM2.5 on daily illness-related absence rate for 2278 elementary schools from 97 counties across Jiangsu Province with data collected in the 2016-17 academic year. We evaluated the effects at school- and county-scales and examined the role of socio-economic and environmental factors with generalized addictive models (GAM). With an interquartile range (IQR, 32 μg/m3) increase in PM2.5 concentration, the relative risk of absence rate for a given school ranged between 1.00 and 2.81. Factors including high economic development level, low health expenditure, dense road network, dense population and low vegetation coverage drove strong effects for schools/counties. For the implementation of efficient clean air policies and public health interventions, we should concern about not only high-polluted areas but also areas under specific socio-economic and environmental conditions.

Along-strike variation of fault-related inversion folds within curved thrust systems: The case of the Central-Northern Apennines of Italy

The along-strike variation of fault-related inversion folds within curved thrust systems is documented by presenting cases from the Central-Northern Apennines of Italy. Fold structures are reconstructed by integrating geological field data and structural restoration of various key balanced cross-sections, which are also constrained by the detailed interpretation of panoramic views, geological field mapping, and structural analysis. The lateral variation from fault-bend to fault-propagation folding is promoted by selective reverse reactivation of precursor, mainly rift-related, normal faults preferentially located along the oblique and frontal ramps. Their space variability is identified within single curved thrust systems of three different size testifying a scale-invariant phenomenon. Fault-bend reactivation and fault-propagation shortcut folding produce a characteristic fold interference pattern at the salient apex of the curved thrust system. The transition style depends on the pattern of the inherited normal fault template and on the amount of shortening achieved in the salient zone. The modest amount of shortening resulting from fault-related inversion folding along regional curved thrust systems is consistent with a basement-involved thick-skinned thrusting style. Recognition of fault-related inversion fold styles and of their along-strike variations represents a useful predictive tool when unravelling the kinematic evolution of curved orogenic belts resulting from positive inversion. Inversion fold development modes and their diagnostic features are also important for investigations of subsurface Earth resources.