Extreme Variability Research Articles

Fitness consequences of variation in social group size are not population‐specific but are associated with access to food in the communally breeding rodent, Octodon degus

AbstractStudies that concurrently investigate the functional benefits of group living in multiple populations of the same species are rare. Over a 3‐year period (2014–2016), we examined two ecologically contrasting populations to test multiple hypotheses for the adaptive significance of group living in the communally breeding rodent Octodon degus. We quantified the size of social units (number of adults, number of adult females), edible vegetation at burrow systems, and per capita offspring weaned (PCOW) in each population. Contrary to expectations, we did not observe population‐specific associations between group size and edible vegetation or PCOW nor universal benefits of group living. In one population, PCOW increased in mid‐sized groups with more edible vegetation. However, this trend was not consistent across years. Notably, we observed a complete reproductive failure in one population during the first year of study, one that was characterized by low rainfall and no detectable edible vegetation. This result is important because reproductive failure occurred regardless of group size, suggesting that communal living may not buffer degus against the harshest of environmental conditions. Examining how social organization shapes individual reproductive success under extreme variation in food availability is an important step towards understanding how populations will respond to a changing climate.

DNA packaging by molecular motors: from bacteriophage to human chromosomes.

Dense packaging of genomic DNA is crucial for organismal survival, as DNA length always far exceeds the dimensions of the cells that contain it. Organisms, therefore, use sophisticated machineries to package their genomes. These systems range across kingdoms from a single ultra-powerful rotary motor that spools the DNA into a bacteriophage head, to hundreds of thousands of relatively weak molecular motors that coordinate the compaction of mitotic chromosomes in eukaryotic cells. Recent technological advances, such as DNA proximity-based sequencing approaches, polymer modelling and in vitro reconstitution of DNA loop extrusion, have shed light on the biological mechanisms driving DNA organization in different systems. Here, we discuss DNA packaging in bacteriophage, bacteria and eukaryotic cells, which, despite their extreme variation in size, structure and genomic content, all rely on the action of molecular motors to package their genomes.

Differential temperature sensitivity of haploid and diploid spores of two red intertidal algae from the Magellan Strait

Spores have crucial importance in the establishment and development of seaweed populations. When the spore release matches with the low tidal period, they experience an extreme variation in the environmental conditions including the temperature. In this study, we assess the photosynthetic responses and growth of haploid (tetraspores) and diploid (carpospores) spores of two Gigartinales species (Mazzaella laminarioides and Iridaea cordata) from sub-Antarctic populations when exposed to an increasing temperature. In the laboratory, freshly released spores were exposed to a temperature gradient (7 [control], 10, 15, and 20 °C) recreating the temperature increase experienced by these spores during typical spring tides. Germination and further growth of spores previously exposed to temperature treatments were assessed. Carpospores and tetraspores exhibited variation in their photosynthetic response (measured as effective quantum yield; ΦPSII) to temperature increase. In Mazzaella laminarioides, only carpospores exhibited a reduction in ΦPSII (by 7–24% at 15–20 °C), while both types of spores of Iridaea cordata were sensitive to temperature increase (12–24% of ΦPSII reduction at 10–20 °C). Spores previously exposed to temperature treatments and maintained at 7 °C and low PAR germinated and developed in germlings. In general, germlings originated from carpospores pre-treated at high temperatures showed higher growth rates. The different responses to temperature increase exhibited by haploid and diploid propagules of both species highlight their ecophysiological capacity to face high-temperature variation ensuring successful recruitment survival.

Seed priming as a promising technique for sustainable restoration of dryland

The success of plant growth and development in dryland restoration relies on seed germination, seedling development, and establishment. The lack of rainfall and extreme temperature variations in arid regions impede germination and seedling establishment, necessitating new approaches and techniques. The present review summarizes the vital role of seed priming techniques for the sustainable restoration of drylands through their effects on enhancing seed germination, seedling growth and development, plants' nutrient use efficiency, soil fertility, essential enzymes, microbial community, and stress adaptation ability, helping to alleviate the effects of abiotic stresses on plants. The importance of seed priming is discussed in both agricultural and ecological restoration contexts. Priming maximizes crop yields, reduces crop failure, and promotes eco‐friendly farming practices. In ecological restoration, seed priming enhances plant establishment and survival, contributing significantly to the restoration of native vegetation and wildlife habitats. The review categorizes seed priming techniques into six subcategories, highlighting their unique advantages for optimizing restoration efforts. The review highlights the underlying mechanisms of seed priming techniques to improve seed germination and plant development in dryland regions, particularly under salinity and drought constraints. While seed priming has proven effective, it also faces several limitations, such as cost, seed longevity, and environmental concerns. Investigating environmentally friendly priming methods and understanding the prolonged effects of priming on seed viability and the environment is crucial. Further research is needed to find cost‐effective, eco‐friendly seed priming methods, and to explore the genetic and molecular bases of stress tolerance in various plant species across diverse environments.

Modeling Water Interactions with Graphene and Graphite via Force Fields Consistent with Experimental Contact Angles.

Accurate simulation models for water interactions with graphene and graphite are important for nanofluidic applications, but existing force fields produce widely varying contact angles. Our extensive review of the experimental literature reveals extreme variation among reported values of graphene-water contact angles and a clustering of graphite-water contact angles into groups of freshly exfoliated (60° ± 13°) and not-freshly exfoliated graphite surfaces. The carbon-oxygen dispersion energy for a classical force field is optimized with respect to this 60° graphite-water contact angle in the infinite-force-cutoff limit, which in turn yields a contact angle for unsupported graphene of 80°, in agreement with the mean of the experimental results. Interaction force fields for finite cutoffs are also derived. A method for calculating contact angles from pressure tensors of planar equilibrium simulations that is ideally suited to graphite and graphene surfaces is introduced. Our methodology is widely applicable to any liquid-surface combination.

Voltage recovery from frozen microbial fuel cells in the laboratory and outdoor field reactors

Extreme temperature variations are a problem that must be faced in the practical application of microbial fuel cells (MFCs), but MFCs are not extensively described for low and even freezing temperatures. This study assessed the effect of low-temperature shock on the power generation performance and microbial community structure of MFCs. Two scales of MFCs, the small (mL-MFC) and the large (L-MFC), were constructed in the laboratory and their performance was evaluated before and after freezing at −18 °C. The experimental results demonstrate that both MFCs were capable of rapidly restoring their voltage to the previous level after thawing. For the mL-MFC (rGO/Ag), the power density recovered from 194.30 ± 10.84 mW/m2 to 195.57 ± 4.02 mW/m2 after thawing. For L-MFC (carbon felt electrodes), the power density increased significantly from the initial 1.79 mW/m2 to 173.90 mW/m2 after thawing, but the performance degradation problem after reactor amplification still needs to be solved. The sediment microbial fuel cell (SMFC) was successfully constructed and operated in a natural outdoor environment to maintain high voltage output after the period of frost. Microbial analysis indicated after the frost period, psychrotolerant microorganisms enriched on the anode, such as Flavobacterium and Psychrobacter, while the relative abundance of anaerobic methanogenic bacterium decreased. Overall, freeze-thaw operations had a non-negative impact on the performance of MFCs and provided some references for their practical applications.

Synoptic‐Scale Extreme Variability of Winter Antarctic Sea‐Ice Concentration and Its Link to Southern Ocean Extratropical Cyclones

AbstractThis study provides a systematic analysis of extreme variability in winter Antarctic sea‐ice concentration (SIC) and its relationship with extratropical cyclones. We characterize sea‐ice variability and cyclone activity in different Southern Ocean sectors using atmospheric reanalyzes and a cyclone‐tracking algorithm, and then quantify the proportion of extreme sea‐ice variability engendered by cyclones of different intensities. The regions with relatively lower sea‐ice area (SIA) (the King Haakon VII, East Antarctic, and Bellingshausen sectors) have an even distribution of cyclones within all intensity ranges, while, in the sectors with higher SIA, the Ross/Amundsen displays a higher number of intense and weak cyclones, and the Weddell sector has the majority of weak cyclones. Our systematic analysis reveals a significant link between extreme variability in winter SIC and: (a) all cyclones in the Ross/Amundsen sector; (b) all but the weakest cyclones in the King Haakon VII, East Antarctic, and Bellingshausen sectors; and (c) all but the most intense cyclones in the Weddell sector. The latter result is explained by the fact that the Weddell sector experiences more frequent, weaker cyclones than the other sectors. Cumulatively, approximately 30%–40% of the extreme sea‐ice variability is caused by extratropical cyclones within all regions.

Exploring extreme brightness variations in blue supergiant MACHO 80.7443.1718: Evidence for companion-driven enhanced mass loss

Context. The evolution of massive stars is dominated by interactions within binary and multiple systems. In order to accurately model this evolution, it is necessary to investigate all possible forms of an interaction in binary systems that may affect the evolution of the components. One of the “laboratories” plausible for this kind of investigation is the massive eccentric binary system MACHO 80.7443.1718 (ExtEV), which exhibits an exceptionally large amplitude of light variability close to the periastron passage of its 32.8-day orbit. Aims. We examine whether the light variability of ExtEV can be explained by a wind-wind collision (WWC) binary system model. We also critically review other models proposed to explain the light curve of ExtEV. Methods. We conducted an analysis of (i) the broadband multicolor photometry of ExtEV spanning a wide range of wavelengths from the ultraviolet to near-infrared, (ii) the time-series space photometry from the Transiting Exoplanet Survey Satellite (TESS), (iii) ground-based Johnson UBV photometry, and (iv) time-series high-resolution spectroscopy. To derive the parameters of the primary component of the system, we fit the spectral energy distribution (SED) and calculated evolutionary models of massive stars that included mass loss. Using radial-velocity data, we determined the spectroscopic parameters of the system. We also fit an analytical model of light variations to the TESS light curve of ExtEV. Results. The ExtEV system exhibits an infrared excess, indicating an increased mass-loss rate. The system does not match the characteristics of B[e] stars, however. We rule out the possibility of the presence of a Keplerian disk around the primary component. We also argue that the scenario with periodic Roche-lobe overflow at periastron may not be consistent with the observations of ExtEV. Analysis of the SED suggests that the primary component has a radius of about 30 R⊙ and a luminosity of ∼6.6 × 105 L⊙. With the analysis of the radial-velocity data, we refine the orbital parameters of ExtEV and find evidence for the presence of a tertiary component in the system. Using evolutionary models we demonstrate that the primary component’s mass is between 25 and 45 M⊙. We successfully reproduced the light curve of ExtEV with our analytical model, showing that the dominant processes shaping its light curve can be attributed to the atmospheric eclipse and light scattered in the WWC cone. We also estimate the primary’s mass loss rate due to stellar wind for 4.5 × 10−5 M⊙ yr−1. Conclusions. ExtEV is most likely not an extreme eccentric ellipsoidal variable, but rather an exceptional WWC binary system. The mass loss rate we derived exceeds theoretical predictions by up to two orders of magnitude. This implies that the wind in the system is likely enhanced by tidal interactions, rotation, and possibly also tidally excited oscillations. Therefore, ExtEV represents a rare evolutionary phase of a binary system that may help to understand the role of companion-driven enhanced mass loss in the evolution of massive binary systems.

Impacts of Rainfall Variability on Streamflow in the Drylands of Northern Kenya: Assessing Water Availability under a Changing Climate

Water availability is a function of climatic and land surface conditions, which determine the amount and distribution of atmospheric water as it reaches the surface. This largely depends on rainfall, whose variability affects water, food and livelihood security. This paper sought to quantify the effects of rainfall variability on water availability in an effort to support effective water resources management. Coefficient of Variation (CV), Standardized Anomaly Index (SAI) and Mann-Kendall trend test approaches were used to assess variability and trends, while correlation and regression analysis were employed to determine effects of rainfall variability on streamflow. A hydrological model, Soil and Water Assessment Tool (SWAT), was used to simulate streamflow with a view to assessing water availability under two climate change scenarios; Representative Concentration Pathways (RCP) 4.5 and 8.5. Results show that the area experiences moderate to extreme rainfall variability, as indicated by CV and SAI values that ranged from 20 to 99% and -2.5 to +3 respectively, resulting in moderate to extreme floods and droughts that often disrupt livelihoods. Current streamflow simulations (1981 – 2020) indicated increasing trends. Near and far future streamflow volumes will decrease by 15% during the April-May-June season while during October-November-December season they will increase by 13%, compared to the present. Increasing trends of rainfall and streamflow indicate that the area has opportunities for rainwater harvesting while the high variability indicates a need for early warning systems to cushion communities from climatic shocks evidenced by the impacts of climate extremes experienced in the area.

Glucose transporter-1 deficiency syndrome with extreme phenotypic variability in a five-generation family carrying a novel SLC2A1 variant.

Glucose transporter-1 (GLUT1) deficiency syndrome (GLUT1-DS) is a metabolic disorder due to reduced expression of GLUT1, a glucose transporter of the central nervous system. GLUT1-DS is caused by heterozygous SLC2A1 variants that mostly arise de novo. Here, we report a large family with heterogeneous phenotypes related to a novel SLC2A1 variant. We present clinical and genetic features of a five-generation family with GLUT1-DS. The 14 (nine living) affected members had heterogeneous phenotypes, including seizures (11/14), behavioral disturbances (5/14), mild intellectual disability (3/14), and/or gait disabilities (2/14). Brain magnetic resonance imaging revealed hippocampal sclerosis in the 8-year-old proband, who also had drug-responsive absences associated with attention-deficit/hyperactivity disorder. His 52-year-old father, who had focal epilepsy since childhood, developed paraparesis related to a reversible myelitis associated with hypoglycorrhachia. Molecular study detected a novel heterozygous missense variant (c.446C>T) in exon 4 of SLC2A1 (NM: 006516.2) that cosegregated with the illness. This variant causes an amino acid replacement (p.Pro149Leu) at the fourth transmembrane segment of GLUT1, an important domain located at its catalytic core. Our study illustrates the extremely heterogenous phenotypes in familial GLUT1-DS, ranging from milder classic phenotypes to more subtle neurological disorder including paraparesis. This novel SLC2A1 variant (c.446C>T) provides new insight into the pathophysiology of GLUT1-DS.

Drivers, changes, and impacts of hydrological extremes in India: A review

AbstractThe frequency of hydrological extremes (droughts and floods) has increased in recent years in India. A dense population, intensive agriculture, and rapidly developing physical infrastructure put India under the risk of hydrological extremes. However, a comprehensive overview of the drivers, changes, and impacts associated with hydrological extremes in India has been lacking. We examine the key processes and the role of climate and human interventions on hydrological extremes in India. We discuss the observed and projected changes in hydrological extremes along with their impacts. While the Indian summer monsoon is the primary driver of the hydrological extremes in India, human interventions (irrigation, reservoir storage, and groundwater pumping) play a crucial role in the changes and variability of hydrological extremes. The relative role of climate change and direct human interventions on changing the intensity and impacts of hydrological extremes need to be considered for future adaptation planning under climate change. The observed increase in the frequency and intensity of hydrological extremes will continue in the future with compound and cascading impacts due to the warming climate. We need to strengthen the observational network, improve hydrological modeling, reduce climate uncertainty, and develop robust early warning systems to adapt and mitigate hydrological extremes in India.This article is categorized under: Science of Water > Hydrological Processes Science of Water > Water Extremes Science of Water > Water and Environmental Change

Assessment of long-term spatio-temporal variability of hot extremes and associated physical mechanism over India

Assessment of long-term spatio-temporal variability of hot extremes and associated physical mechanism over India

Genome-Wide Identification, Molecular Characterization, and Expression Analysis of the HSP70 and HSP90 Gene Families in Thamnaconus septentrionalis.

Heat shock proteins (HSPs) are a class of highly conserved proteins that play an important role in biological responses to various environmental stresses. The mariculture of Thamnaconus septentrionalis, a burgeoning aquaculture species in China, frequently encounters stressors such as extreme temperatures, salinity variations, and elevated ammonia levels. However, systematic identification and analysis of the HSP70 and HSP90 gene families in T. septentrionalis remain unexplored. This study conducted the first genome-wide identification of 12 HSP70 and 4 HSP90 genes in T. septentrionalis, followed by a comprehensive analysis including phylogenetics, gene structure, conserved domains, chromosomal localization, and expression profiling. Expression analysis from RNA-seq data across various tissues and developmental stages revealed predominant expression in muscle, spleen, and liver, with the highest expression found during the tailbud stage, followed by the gastrula, neurula, and juvenile stages. Under abiotic stress, most HSP70 and HSP90 genes were upregulated in response to high temperature, high salinity, and low salinity, notably hspa5 during thermal stress, hspa14 in high salinity, and hsp90ab1 under low salinity conditions. Ammonia stress led to a predominance of downregulated HSP genes in the liver, particularly hspa2, while upregulation was observed in the gills, especially for hsp90b1. Quantitative real-time PCR analysis corroborated the expression levels under environmental stresses, validating their involvement in stress responses. This investigation provides insights into the molecular mechanisms of HSP70 and HSP90 in T. septentrionalis under stress, offering valuable information for future functional studies of HSPs in teleost evolution, optimizing aquaculture techniques, and developing stress-resistant strains.

Landscape evolution in the southern Transantarctic Mountains during the early Miocene (c. 20–17 Ma) and evidence for a highly dynamic East Antarctic Ice Sheet margin from the southernmost volcanoes in the world (87°S)

Observations of ice sheet stability in Antarctica in the past, during significantly warmer climatic periods than today, are hampered by a paucity of continental outcrops but they are essential if we are to test and more fully understand established concepts of ice sheet growth and decay and robustly predict Earth's future during rapid global warming. In this paper we use the unique terrestrial record preserved in the three most southerly volcanoes on Earth to reconstruct Antarctica's environmental landscape in the Transantarctic Mountains for three time slices (at 20.1, 19.31 and c. 17 Ma). We demonstrate that the East Antarctic Ice Sheet margin was highly dynamic and fluctuated greatly during the Early Miocene. The period included a much-reduced ice cover that left the southern Transantarctic Mountains virtually ice-free, although a few tidewater glaciers reached the shores of the Early Miocene Ross Sea (Sheridan Bluff; 20.1 Ma); and a substantially thicker, much more voluminous ice mass (represented by volcanism at Mount Early; 19.31 Ma). An intermediate stage of ice retreat is also indicated (at c. 17 Ma), when the East Antarctic Ice Sheet had again withdrawn to behind the Transantarctic Mountains. It is represented by a subglacial volcanic centre identified remotely by aerogeophysics and sampled only as glacial erratics. The associated ice cover at c. 17 Ma had a relatively low surface elevation but it was confluent with thin ice domes that covered the adjacent mountains. Although the ice margin probably did not extend down to the Ross Sea coast, several glaciers fed icebergs into the Ross Sea. The large ice sheet indicated by the Mount Early volcanic centre is the only known physical record of a significant glacial event that took place at 19.31 ± 0.32 Ma (‘Mount Early glacial’). The records examined at the other two volcanic sites correspond to eruptions during periods of substantially reduced ice in Antarctica, of which that at 20.1 ± 0.4 Ma is the most remarkable (‘Sheridan Bluff interglacial’). The causes of the extreme variations in ice sheet thickness and extent indicated are uncertain but they occurred during a period of rapidly fluctuating atmospheric CO2 compositions. Although Milankovitch astronomical forcing probably also played a significant part, the results suggest that the East Antarctic Ice Sheet was highly susceptible to comparatively slight changes in CO2 during the warm Early Miocene.

Lower extremity inter-joint coupling angles and variability during gait in pediatric hypermobility spectrum disorder

Complex musculoskeletal complications in children with hypermobility spectrum disorder (HSD) include pain, proprioception deficits, and joint instability, which may result in movement dysfunction during walking. However, no studies have explored the inter-joint coordination deficits in children with HSD. The purpose of this study was to determine the lower extremity inter-joint coupling angles, patterns, and variability during walking in children with HSD compared to children without HSD (non-HSD). Ankle, knee, and hip kinematics during the stance phase of walking in 18 children with HSD and 18 children without HSD were measured using three-dimensional motion analysis. Coupling angles, patterns, and variability of hip-knee, hip-ankle, and knee-ankle were quantified in the sagittal, frontal, and transverse planes using vector coding techniques. Statistical modeling of coupling angles on sine and cosine scales and bootstrapped standard errors were used to compare coupling angles between HSD and non-HSD groups. Permutational multivariate analysis of variance and statistical non-parametric mapping two-sample t-tests were used to compare the coupling patterns and variability between HSD and non-HSD groups, respectively. Our results indicated that coupling angles, patterns, and variability were not significantly different between the groups. These findings suggest that lower extremity inter-joint coordination and its variability during walking might not be a promising area for further research or intervention in children with HSD. Further research could use other biomechanical methods to investigate coordination deficits in pediatric patients with HSD, and how aging and disease progression are associated with coordination deficits in individuals with HSD.

How to quantify developmental synchrony in malaria parasites

Malaria infections represent an iconic example of developmental synchrony, where periodic fevers can result when the population of parasites develops synchronously within host red blood cells. The level of synchrony appears to vary across individual hosts and across parasite species and strains, variation that—once quantified—can illuminate the ecological and evolutionary drivers of synchrony. Yet current approaches for quantifying synchrony in parasites are either biased by population dynamics or unsuitable when population growth rates vary through time, features ubiquitous to parasite populations in vitro and in vivo. Here we develop an approach to estimate synchrony that accounts for population dynamics, including changing population growth rates, and validate it with simulated time series data encompassing a range of synchrony levels in two different host-parasite systems: malaria infections of mice and human malaria parasites in vitro. This new method accurately quantifies developmental synchrony from per capita growth rates using obtainable abundance data even with realistic sampling noise, without the need to sort parasites into developmental stages. Our approach enables variability in developmental schedules to be disentangled from even extreme variation in population dynamics, providing a comparative metric of developmental synchrony.

Analysis of extreme precipitation variation characteristics in mountain grasslands of arid and semi-arid regions in China

Introduction: With global warming, the disaster losses caused by extreme precipitation events are increasing. The poor natural conditions and climate change make the arid and semi-arid mountainous grassland area a sensitive region of climate change. The study on the spatio-temporal variation characteristics of extreme precipitation events in this region is helpful to improve the ability of climate prediction and disaster prevention and reduction in grassland.Methods: Based on the daily precipitation data of four meteorological monitoring stations in the Yinshanbeilu from 1970 to 2020, the trend analysis, M-K test and wavelet analysis were used to select seven typical extreme precipitation indicators to analyze the temporal and spatial characteristics of extreme precipitation.Results and Discussion: The results showed that the precipitation in the Yinshanbeilu increased in the past 51a, and the number of heavy rain days increased significantly. The significance test of CDD and CWD showed that the number of continuous dry days and continuous wet days decreased abruptly. The spatial analysis showed that the high value areas of R95p, R95d and PRCRTOT were all located in Siziwang Banner, and it could be concluded that the extreme precipitation risk was the highest in Siziwang Banner, while the low value areas of SDII, Rx1day, R95p and PRCRTOT were all located in Sonid Right Banner, which could be inferred that the Sonid Right Banner was relatively dry. The first main cycle of the seven indexes of extreme precipitation almost runs through the whole time series, and the starting point of the minimum main cycle changes inconsistent. In addition to the number of consecutive dry days, the other indices have a good correlation with annual precipitation, flood season and monthly precipitation from June to September, and July is the peak period of extreme precipitation events.

Impacts of extreme precipitation on water conservation in Beijiang River Basin, China

Water conservation, which has been regarded as one of the most crucial ecosystem service functions of river basins, is a key factor for sustainable development, that has garnered widespread attention in the context of climate change. However, little attention has been paid to daily water conservation and its response to extreme precipitation events. In this study, we selected the Beijiang River Basin (BJRB) as the study area, which is an important ecological barrier for the Guangdong-Hong Kong-Macau Greater Bay Area (GBA), based on the distributed hydrological model WEP-L (Water and Energy transfer Processes in Large River basin) and water balance equation, the spatiotemporal characteristics of extreme precipitation and four daily water conservation indicators (maximum 1 day, maximum 3 day, maximum 5 day, maximum 7 day water conservation) in the BJRB from 1965 to 2009 were analysed, and the responses of these indicators to extreme precipitation were investigated. The results reveal that (1) the amount (RX1day, RX3day, RX5day, RX7day, R95p, and R99p), intensity (SDII), and frequency (R50mm) of extreme precipitation increased in the BJRB during 1965–2009, with SDII undergoing a significant increase. (2) The four water conservation indicators were positive, indicating that the watershed reduced peak flow during the extreme precipitation period by accumulating precipitation. The rate of increase of the four water conservation indicators were lower than that of extreme precipitation indices, there will be more extreme precipitation converted into surface runoff, thereby increasing the risk of flooding. The four indicators increased in the southern and northern regions of the BJRB, while decreased in the central region during 1965–2009. (3) The four indicators were generally positively correlated with most of the extreme precipitation indices in the northern BJRB, especially RX1day, RX3day, RX5day, RX7day, R99p, and R50mm. The results provide a scientific reference for water conservation adaptation to extreme precipitation variations, protection of the ecological environment, and the prevention and reduction of disasters in the region.

3D printing with a 3D printed digital material filament for programming functional gradients

Additive manufacturing, or 3D printing attracts growing attention as a promising method for creating functionally graded materials. Fused deposition modeling (FDM) is widely available, but due to its simple process, creating spatial gradation of diverse properties using FDM is challenging. Here, we present a 3D printed digital material filament that is structured towards 3D printing of functional gradients, utilizing only a readily available FDM printer and filaments. The DM filament consists of multiple base materials combined with specific concentrations and distributions, which are FDM printed. When the DM filament is supplied to the same printer, its constituent materials are homogeneously blended during extrusion, resulting in the desired properties in the final structure. This enables spatial programming of material properties in extreme variations, including mechanical strength, electrical conductivity, and color, which are otherwise impossible to achieve with traditional FDMs. Our approach can be readily adopted to any standard FDM printer, enabling low-cost production of functional gradients.

Changes in extreme precipitation indices across Algeria climate zones

AbstractExtreme precipitation events can have a significant impact on the environment, agriculture, economy and safety, making close monitoring of their short‐ and long‐term trends essential for the development of effective mitigation and adaptation strategies. In this study, we analysed 16 in situ observation datasets from four different climate zones in Algeria, spanning from 1969 to 2021. The trend analysis was conducted using the original Mann–Kendall test and seven modified tests to eliminate the effects of short‐term persistence. Our findings reveal a significant increasing trend of extreme precipitation variability for most stations in the Warm Mediterranean climate zone, except for the Consecutive dry days index, which showed a negative trend for the same zone, while stations in the Cold/Warm semi‐arid climate and Cold desert climate (Bwk) zones showed a decreasing trend. Additionally, all index series with significant long‐term trends were affected by a significant shift in their means, which was confirmed by both the Lombard and Pettitt tests. However, when we used the modified MPT and the test eliminating the effects of long‐term persistence, the significance of the shifts and the trend decreased. Our results suggest that while extreme precipitation events have been increasing in some parts of Algeria; the trend may not be statistically significant in the long‐run, indicating the necessity of revisiting and refreshing the findings of previous studies for a more current perspective.