Shape Of Fragments Research Articles

Evidences of microplastics in aerosols and street dust: a case study of Varanasi City, India.

Microplastics (MPs) are ubiquitous in our environment. Its presence in air, water, and soil makes it a serious threat to living organisms and has become a critical challenge across ecosystems. Present study aimed to assess the abundance of MPs in aerosols and street dust in Varanasi, a typical urban city in Northern India. Airborne particulates and street dust samples were collected from various sampling sites around Varanasi City. The physical identification of MPs was conducted by binocular microscopy, fluorescence microscopy, and scanning electron microscopy (SEM), while elemental analysis was made by energy-dispersive X-ray (EDX). Finally, Fourier-transform infrared spectroscopy (FTIR) was used for chemical characterization of MPs. Presence of MPs in both aerosols and street dust from all selected sampling sites was confirmed, however with varying magnitude. MPs of different colors having the shape of fragments, films, spherules, and fibers were recorded in the study while fragments (42%) in street dust and fibers (44%) dominated in aerosols. Majority of the MPs were < 1mm in size and were primarily polypropylene, polystyrene, polyethylene, polyethylene terephthalate, polyester, and polyvinyl chloride types. The EDX spectra showed the presence of toxic inorganic contaminants like metallic elements on MPs, especially elements like aluminum, cadmium, magnesium, sodium, and silicon found to adsorb on the MPs. Presence of MPs in the airborne particulates and street dust in Varanasi is reported for the first time, thus initiating further research and call for a source-specific management plan to reduce its impact on human health and environment.

Studying Sharp Changes of Urban Landscape: Concession Within Agricultural, Hydraulic, and Maritime Public Domain in Kelibia City, Northern Tunisia

Coastal cities are desirable places to live and work which results in ongoing and increasing urbanization. In southern Mediterranean countries, coastal urbanization often occurs on croplands. This expansion is frequently on most productive croplands and emerges as an important sustainability concern. The aim of this study is to quantify urban growth over lands in Kelibia city, a coastal region in Tunisia that is one of the most threatened Mediterranean regions. We describe the changes in urban structures during the period of 2012–2016 by using Multi dates Pleiades images and using Otsu binary and sample-based Edge segmentation. Otsu segmentation showed higher accuracy than Edge segmentation method. Based on Otsu binary maps, urban areas were quantified in two dates. The results illustrated a dramatic increase of urban areas at the expense of agricultural land, maritime public domain (MPD) and hydraulic public domain (HPD). Analysis of parameters for urban sprawl quantification evaluated a sharp increase of urbanization rate, intensity, and dynamic degree. FRAGSTAT metrics described the change of landscape structure due to the increase of fragmentation pace, compactness degree, shape complexity, and proximity reduction. This significant urban change in extent and structure during a short temporal scale could be considered as a serious issue. For this reason, the implementation of systematic strategies for urban monitoring requires citizen awareness, law enforcement, and scientific supervision to mitigate land consumption, reduce flooding vulnerability, and to control the environmental impacts of urbanization.

Abstract 1912: A versatile computational pipeline for the preprocessing of cell-free DNA fragmentation data

Abstract Cell-free DNA (cfDNA) emerges as a promising liquid biopsy biomarker for cancer diagnosis and patient monitoring. Complementing mutation-based assays, cfDNA carries information about epigenetic modifications from decaying cells. This information is encoded in the shape of the cfDNA fragments. Specifically, fragments from cancer tend to be shorter than those originating from other adult cells, enabling a distinction between cancer patients and healthy individuals. Additional cfDNA features such as fragment end motifs and information on nucleosome positioning provide further insight into cancer biology. These cfDNA measures are typically inferred from low-pass whole genome sequencing and subsequent bioinformatics processing. A key bioinformatics step is the alignment of DNA sequencing reads to the reference genome, which critically depends on preprocessing steps such as read trimming and alignment filters. A good understanding of preprocessing settings is thus crucial to derive accurate information from cfDNA. We therefore investigated to what extent preprocessing choices affect cfDNA analysis. To this end, we have built a robust bioinformatics pipeline that evaluates a range of possible preprocessing settings. The pipeline is implemented in a bioinformatics workflow engine, enabling a scalable and reproducible workflow. We are currently evaluating the effect of preprocessing on global and regional fragmentation patterns, detection of nucleosome positioning and identification of fragment end motifs. The different preprocessing settings are also evaluated for their ability to distinguish cancer from control samples using cfDNA fragmentation information. We are benchmarking the pipeline using cfDNA datasets from multiple centres to ensure our findings are generalizable over different platforms and experimental procedures. Our investigations will allow us to build a versatile bioinformatics preprocessing pipeline for the analysis of cell-free DNA fragmentation data. Citation Format: Ivna Ivankovic, Zsolt Balázs, Todor Gitchev, Daniel Trejo Banos, Norbert Moldovan, Panagiotis Balermpas, Jonas Willmann, Nicolaus Andratschke, Florent Moulière, Michael Krauthammer. A versatile computational pipeline for the preprocessing of cell-free DNA fragmentation data [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1912.

Differential Impact of Forest Fragmentation on Fluctuating Asymmetry in South Amazonian Small Mammals

(1) Background: Southern Amazonia encompasses some of the most human-impacted and deforested regions of South America, resulting in a hyper-fragmented landscape. In this context, by using a geometric morphometrics approach, we aimed to examine the effect of forest fragmentation on developmental instability (DI) of the mandible, assessed by variation of fluctuating asymmetry (FA), in four neotropical small mammal species inhabiting the municipality of Alta Floresta (Brazil). (2) Methods: The impact of fragment area, fragment shape, isolation, and edge length on DI were assessed by measuring variation in mandibular FA in the long-tailed spiny rat (Proechimys longicaudatus), the hairy-tailed bolo mouse (Necromys lasiurus), the woolly mouse opossum (Marmosa demerarae), and the Amazonian red-sided opossum (Monodelphis glirina). Mandibles from a total of 304 specimens originating from different-sized fragments (ranging from 5 to 900 ha) were used. Twelve homologous landmarks were digitized in photographs of the mesial view of each hemi-mandible. (3) Results: The two largest species, P. longicaudatus and M. demerarae, exhibited significantly higher levels of FA in mandibular shape in small fragments (5–26 ha) in comparison to large ones (189–900 ha). Edge length negatively impacted M. demerarae, the only arboreal species, reinforcing its strongest dependence on core forest habitats. (4) Conclusions: For small mammal communities, we propose that fragments &gt;~200 ha should be the focus of conservation efforts, as both resilient and more sensitive species would benefit from their more preserved biotic and abiotic conditions. Conversely, fragments &lt;~25 ha seem to lead to a significant increase in stress during developmental stages.

Numerical simulation of fragment impacting solid rocket motors

For the initiation characteristics of solid rocket motors (SRMs) filled with high-energy solid propellant under fragment impact, the related theoretical critical criterion for shock initiation was established based on the critical energy criterion and equivalent analysis method. Afterward, numerical simulation of fragment impacting SRM was carried out by using the ANSYS/LS-DYNA software and the nonlinear finite element method. Based on the calculated pressure and reactivity in the high-energy solid propellant grain, the shock critical initiation velocity of SRM and its variation with different forms of fragments and impact conditions were determined. It is found that the numerical simulation results under typical conditions are in good agreement with the data calculated with the developed theoretical critical criterion for shock initiation of SRM. However, the shock initiation mechanism becomes more complex when the case thickness of SRM increases to more than 5 mm; thus, the applicability of the developed theoretical critical criterion reduces. Moreover, it is found that all the case thickness, fragment shape, material properties of the fragment, and impact attitude can significantly affect the shock critical initiation velocity of SRM, even the initiation position and time. First, the critical velocity increases linearly with the increase in case thickness, and the increment rate is faster beyond the thickness of 6 mm. Second, the shock critical initiation velocity induced by fragments with different shapes is as follows: spherical fragment &amp;gt; cubic fragment &amp;gt; cylindrical fragment, while the initiation capacity of different fragment materials is ranked as follows: tungsten alloy &amp;gt; 45 steel &amp;gt; 2024 aluminum. Third, the effects of impact attitude on the shock critical initiation velocity, position and time are complex, and these effects are also influenced by fragment shape. When the impact angle is less than 60°, there is a higher shock critical initiation velocity of SRM under inclined impact than that under positive impact. In addition, the critical velocity induced by cubic fragment is the highest under the combination of vertex impact and positive impact. The variation of the critical velocity under this condition is approximately consistent with that by impacting with cylindrical fragment. Furthermore, when the impact angle is greater than 60°, the shock critical initiation velocity of SRM is less obviously influenced by impact attitude and fragment shape. Meanwhile, the critical velocity decreases sharply under this condition, which indicates that it is easier for SRM to detonate.

Distribution and occurrence of microplastics in wastewater treatment plants

Microplastic pollution is an alarming problem into aquatic environment. Wastewater treatment plants (WWTPs) with applied technologies are strictly interested in the technical challenges with budget calculations and sustainable development without contaminants. WWTPs are suspected as potential sources discharging microplastics (MPs) into the environment. This study investigated the distribution and occurrence of MPs in influent and effluent of three typical industrial wastewater treatment plants (WWTPs) named HoaCam WWTP (HC WWTP), DaNang WWTP (DN WWTP), and HoaKhanh WWTP (HK WWTP) in Danang city, Vietnam. The results showed that the abundance of MPs total is 183–443 particles/L and 138–340 particles/L in the influent and the effluent. The average MPs removal efficiency obtained 25.5%, 21.8% and 25.3% at HC, DN and HK of three WWTPs, respectively. Hence, the average loading capacity of MPs discharged to recipient sources is 3.8 × 10 7 , 8.3 × 10 7 and 1.5 × 10 9 particles per day in the HC, DN, HK WWTPs, respectively. The majority of MPs identified in this study included a profile of size, shape type, color and chemical compositions of MPs. The sizes of MPs highly varied from 1.6 to 5000 μ m with the abundant MPs types of fiber and fragment in both the influent and the effluent. In addition, the colors of MPs such as yellow, white, blue and black are presented. Using Fourier Transform Infrared spectroscopy (FTIR), the main polymer compositions of MPs included polyethylene terephthalate (PET), polyethylene (PE), nylon and polyvinyl chloride (PVC) were determined in three WWTPs. • WWTPs were considered as potential sources discharging MPs into the aquatic environment. • The abundance of MPs in the influent is lightly higher than that in the effluent of three WWTPs. • The fibber and fragment shapes in both the influent and the effluent of WWTPs were dominant. • Main polymer compositions of microplastics were polyethylene terephthalate (PET), polyethylene (PE), nylon and polyvinyl chloride (PVC) in WWTPs.

Combination of electronically driven micromanipulation with laser desorption ionization mass spectrometry - The unique tool for analysis of seed coat layers and revealing the mystery of seed dormancy.

Electronically driven micromanipulation (EDM) with microscopic control was used as a novel tool for sample preparation prior to direct (matrix assisted) laser desorption/ionization mass spectrometric ((MA)LDI-MS) analysis of mature pea seed coat composition in defined layers. Microscissors were used for seed coat fragment shape adjustment, microtweezers for sample holding and "microjackhammer" Milling Pro for precise mechanical removing of cell layers in defined depths (2, 5 or 10μm). These procedures circumvent the application of embedding media or enzymatic digestion of seed coat that would complicate mass spectra interpretation (presence of matrix signals, analyte signals enhancement or attenuation) and represent alternative for 3D metabolites profiling. In addition, microinjector was used to apply a solution on intact or micropeeled seed coat surface in nano-volumes, i.e. MALDI matrix and/or lithium salt, that provide improvement of signal of sugars. Utilization of EDM enabled optimization of matrix composition on a single small fragment of seed coat overcoming thus problems with biological (seed to seed) variability. LDI-MS data were studied by multivariate statistical analysis and significant metabolites in particular layers of seed coats were identified. Normalized intensities of signals (NS) of long-chain hydroxylated fatty acids (HLFA) on intact dormant pea genotype (JI64) seed coats were significantly higher than in their counterparts treated by micropeeling confirming HLFA accumulation in outermost layers (cutin). Fatty acids distribution differences between dormant and non-dormant genotypes were explored in detail. On the other hand, NS of sugar chains and particular polyphenols were significantly higher in micropeeled seed coats of studied dormant and non-dormant genotypes than in intact seed coats. Furthermore, combination of EDM with mass spectrometry imaging (MSI) allowed vertical profiling of metabolites in hilum (a place of former attachment of seed to maternal plant) and comparison of its composition with surrounding tissues. The obtained results contribute to the understanding of relations between seed coat chemical composition and physical seed dormancy.

Surrogate drag model of non-spherical fragments based on artificial neural networks

The hazard evaluation of the fragments produced from an explosion requires an accurate prediction of the motion of fragments subjected to gravity and aerodynamic forces. The drag coefficient (Cd) is among the most crucial components of various aerodynamic models. Limited experiments cannot reproduce the Cd (Mach) curves of all shapes of fragments. In this study, we develop a surrogate model of the average drag coefficient, C¯d, for the randomly tumbling non-spherical fragment using artificial neutral networks. To train and validate the surrogate model, a comprehensive dataset was developed through mesoscale simulations of Cd for a wide variety of fragment shapes combined with icosahedron average method. The surrogate model shows that the dependence of C¯d on different Mach numbers varies with fragment shape. The fully validated surrogate model of C¯d allows us to derive the statistics of C¯d for a host of fragments from a specific explosion, subsequently gaining insight into the terminal ballistics of the fragments.

Bisphenol B disrupts testis differentiation partly via the estrogen receptor-mediated pathway and subsequently causes testicular dysgenesis in Xenopus laevis

There is growing concern about adverse effects of bisphenol A alternatives including bisphenol B (BPB) due to their estrogenic activity. However, limited data are available concerning the influences of BPB on male reproductive development in vertebrates, especially in amphibians, which are believed to be susceptible to estrogenic chemicals. The present study investigated the effects of 10, 100 and 1000 nM BPB (2.42, 24.2 and 242 μg/L) on testis development in Xenopus laevis, a model amphibian species for studying gonadal feminization. We found that exposure to BPB from stages 45/46 to 52 resulted in down-regulation of testis-biased gene expression and up-regulation of ovary-biased gene and vitellogenin (vtgb1) expression in gonad-mesonephros complexes (GMCs) of tadpoles at stage 52, coupled with suppressed cell proliferation in testes and reduced gonadal metameres, resembling the effects of 17ß-estradiol. Moreover, an estrogen receptor (ER) antagonist ICI 182780 antagonized BPB-caused up-regulation of ovary-biased gene and vtgb1 expression to some degree, indicating that the effects of BPB on X. laevis testis differentiation could be partly mediated by ER. All observations demonstrate that early exposure to BPB inhibited testis differentiation and exerted certain feminizing effects during gonadal differentiation. When exposure was extended to post-metamorphosis, testes exhibited histological and morphological abnormalities including segmented, discontinuous and fragmented shapes, besides altered sex-dimorphic gene expression. Notably, most of BPB-caused alterations were not concentration-dependent, but the lowest concentration indeed exerted significant effects. Overall, our study for the first time reveals that low concentrations of BPB can disrupt testis differentiation partly due to its estrogenic activity and subsequently cause testicular dysgenesis after metamorphosis, highlighting its reproductive risk to amphibians and other vertebrates including humans. Our finding also implies that estrogenic chemicals-caused testis differentiation inhibition at tadpole stages could predict later testicular dysgenesis after metamorphosis, meaning a possibility of early detection of abnormal testis development caused by estrogenic chemicals.

Morphology Characteristics of the Fragments Produced by Rock Grain Crushing

The morphology of fragments produced by grain fragmentation is a cause for great concern in many areas such as rockfill dam and the mining industry. Therefore, there is a need to conduct a quantitative analysis of the morphology characteristics of fragments produced by rock grain crushing. So far, few studies have focused on the qualitative analysis of fragment morphology, and quantitative studies are rare. This study presents a quantitative investigation of the morphology characteristics of fragments produced by the crushing of two groups of rounded and angular rock grains. The intact grain morphology is acquired using a 3D scanner, and the grain fracture and fragmentation are simulated using the combined finite-discrete element method (FDEM). The mesh refinement study indicates that a finite-element mesh size that leads to the fracture process zone to be discretized into at least five or six elements is used to eliminate or minimize the mesh size effect. Regular and spherical grains tend to get smaller largest fragments and larger second-largest fragments compared with grains with lower sphericity and convexity because of different fracture modes. Small differences have been observed in the distributions of fragment shape descriptors for grains in two groups. However, no monotonic relationship has been found between the distribution of shape descriptors and the fragment size, except sphericity. The distributions of sphericity for different size groups clearly suggest that larger-sized fragments tend to be more angular, which is consistent with the existing results.

Three-axial shape distributions of pebbles, cobbles and boulders smaller than a few meters on asteroid Ryugu

Over a broad size range, the shapes of impact fragments from catastrophic disruptions are distributed around the mean axial ratio 2: √2: 1, irrespective of experimental conditions and target materials. Although most blocks on asteroids are likely to be impact fragments, there is not enough quantitative data for reliable statistics on their three-axial lengths and/or ratios because it is difficult to precisely estimate the heights of the blocks. In this study, we evaluate the heights of blocks on asteroid Ryugu by measuring their shadows. The three-axial ratios of ~4100 small blocks with diameters from 5.0 cm to 7.6 m in Ryugu's equatorial region are investigated using eight close-up images of narrower localities taken at altitudes below 500 m, i.e. at <5.4 cm/pixel resolution, obtained immediately before the second touch-down of the Hayabusa2 spacecraft. The purpose of this study is to investigate the block shape distribution, which is important for understanding the geological history of asteroid Ryugu. Specifically, the shape distribution is compared to laboratory impact fragments. Our observations indicate that the shape distributions of blocks smaller than 1 m on Ryugu are consistent with laboratory impact fragment shape distributions, implying that the dominant shape-determining process for blocks on Ryugu was impact fragmentation. Blocks several meters in size in the equatorial region seem to be slightly flatter than the rest, suggesting that some blocks are partly buried in a bed of regolith. In conclusion, the shape distributions of blocks from several-cm to several-m in the equatorial region of asteroid Ryugu suggest that these are mainly fragments originating from the catastrophic disruption of their parent body and/or from a later impact.

Distribution of shear fragments classified by morphology

In studies on metal shell under internal explosive loading, unlike brittle metals, ductile metals usually exhibit shear fracture. Existing literature mostly focuses on slip fracture caused by unidirectional shear fracture, in fact, the shell fractures in the two directions of maximum shear stress, making morphology of the fragments diversified, considering fragment morphology in the distribution may achieve a better description. In previous studies, Poisson mixtures and Weibull mixtures model are only used for fragment distribution statistics as a functional form, and parameters (weight coefficient and distribution modulus) in the function lack physical process description. In this paper, an experimental study on the fragmentation of 50SiMnVB steel shell under TNT internal explosive loading was carried out. Through the observation and analysis of recovered fragments, the shear fragments with cross-sections of parallelogram, right-angled trapezoid, and isosceles right-angled triangle are divided into three types: A, B, and C. According to “A-type fragments created by the parallel through-the-thickness fractures, B-type and C-type fragments created by interaction of intersecting fractures,” the morphological parameters of fragments in the distribution model were derived, including fragment size (width, length, thickness, mass, etc.), shape parameters, and weight coefficient. Weibull mixture distribution model is used to describe the distribution of the total fragments, whereas Weibull distribution is used to describe the distribution of each type of fragment. Through the comparison of theoretical calculations and experimental data, the applicability of the theoretical model in the field of “shear fracture of ductile steel shell under internal explosive loading” is verified.

Monitoring diet with automated microhistology

AbstractMicroscopic analysis of indigestible fragments (microhistology) has long been used to monitor diets of wildlife, but the method is slow and difficult to replicate. We automated microhistology analysis by training a computer vision network to quantify the percent slide cover of identified fragments. We compared automated and manual analyses for 3 reference mixes with known proportions of plants and for samples of feces collected during the fall of 2016 and 2017 from white‐tailed deer (Odocoileus virginianus) and goats (Capra aegagrus) with access to the same plants in the wild at the Sonora Research Station, Edward's Plateau, Texas. Consistent size and shape of fragments for grass (Bothriochloa ischaemum) and conifer (Juniperus ashei) were associated with absolute errors of 6 to 16% for both methods. Irregular fragments of leaves and acorns of oak (Quercus virginiana) were underestimated by both methods. Small star‐shaped trichomes of a forb (Croton fruticulosus) were underestimated by computer analysis but overestimated by manual analysis. Fecal fragments from deer were more diverse in plant species and more variable in thickness and shape than those of goats. Computer analysis estimated conifer content of the goat diet within 4% of the manual estimate whereas those estimates for deer were up to 35% greater than the manual estimate. Automated analysis of digital images can increase the rigor of microhistology by expanding the size of sample sets and facilitating the routine use of calibrated references to assess errors in estimates of diet.

Aggregate shape effect on fracture and breakage of cementitious granular materials

To assess the aggregate shape influences on the cementitious granular material fracture and breakage behaviors, mortar samples containing two types of aggregates with same material but different shapes, namely, irregular glass particles and rounded glass particles, are compressed under quasi-static to high strain rate (1000–3500 s−1) loadings. Experimental results reveal that the extent of aggregate shape effect on the mortar stiffness is significantly enhanced with the increase of strain rate or cement strength. Although the critical strain energy is discovered to be aggregate shape independent, different microscopic fracture evolutions induced by the aggregate shape influences still exist and are effectively reflected by the corresponding coupled evolution of fragment size and shape. Meanwhile, the fracture locality preference within the aggregate particles is also validated by the associated microscopic evidence. This study sheds light on the future high strength granular composite material design, in particularly, upon high strain rates.

Outdoor Atmospheric Microplastics within the Humber Region (United Kingdom): Quantification and Chemical Characterisation of Deposited Particles Present

Atmospheric microplastics (MPs) have been consistently captured within air samples on a global scale. Locations with high human activity are reported to have high MP levels. An urban sampling site in the Humber region (U.K.) has been sampled over a 13-month period, providing a seasonal variation profile of MP levels, size, shape, and polymer types that humans are exposed to. Mean MP levels, measured using passive fallout into a container, were 3055 ± 5072 MP m−2 day−1 (1164 median). An increase in levels with a decrease in MP size was observed, consisting of mainly film-shaped MPs (67%) that were polyethylene (31%) and nylon (28%) polymer types. No relationship between rainfall and MP fallout levels was observed. In parallel, MPs within five urbanised locations relevant to human exposure were characterised over a 2-week period. An overall MP mean (and standard deviation) of 1500 ± 1279 was observed (1012 median), from which petroleum resin accounted for 32% of MP polymer type, with a higher prevalence within industrial and roadside zones. These comprised mainly fragment (52%) and film (42%) shapes, and the MPs levels increased with decreasing particle size. The results provide novel information on characterising polymer levels and types, and can inform cellular toxicity studies, investigating the consequences of human MP exposure.

Distribution and characteristics of microplastics in surface water at some beaches in Thanh Hoa province, Viet Nam

Microplastics present in high density in coastal marine environments have been reported by many published works worldwide. Microplastic presence poses a major threat to all organisms that come into direct contact with them in the aquatic environment because they are non-biodegradable and adsorbable to some toxic substances. Besides, through the food chain, it can affect human health. This study provides data on the density and characteristics of microplastics such as shape, size, and color in the aquatic environment of three beaches (Hai Tien, Sam Son, Hai Hoa) in Thanh Hoa province. Microplastics were detected at all sampling locations at high abundance. The largest microplastic abundance was 44.1 items/m3 at Hai Tien beach, while the smallest was 15.5 items/m3 at Sam Son beach. The results indicated that the most common microplastic shape was fragment shape which accounted for 50.2 to 80.2% of total microplastics. The size was smaller than 500 µm covered from 66.1 to 87.7 % of total microplastics. Among that, white, yellow, and black are the main colors of microplastics in the aquatic environment of this region.

Road density and forest fragmentation shape bat communities in temperate mosaic landscapes

Road construction is expanding worldwide, exacerbating both direct mortality by road-kills and habitat fragmentation, especially for mobile vertebrates such as bats. Understanding how road density affects bat communities in mosaic landscapes of various compositions and configurations is therefore critical. We acoustically sampled bat communities in 172 landscapes of southern France to: (i) disentangle the relative and interacting effects of road density and forest fragmentation by farmland on the activity of bat communities; (ii) investigate how road density affects different aspects of bat diversity (taxonomic, functional and phylogenetic) and species activity according to their life-history traits; and (iii) assess whether road density effects on bats change with the level of forest fragmentation. Forest amount and patchiness were more important than road density for all components of bat diversity, except for functional evenness. Bat diversity peaked in landscapes with intermediate levels of forest fragmentation, while road density had negative effects on functional and phylogenetic diversity. The effect of road density on the activity of R. ferrumequinum, R. hipposideros, N. leisleri and P. pipistrellus was only negative in landscapes with either a low forest amount or a low number of forest patches. By better understanding interactions between forest fragmentation and road density, our study will contribute to a more adequate landscape planning that will improve the resilience of bat communities to both road expansion and forest fragmentation. Moreover, the complex landscape-level interactions between habitat fragmentation and matrix quality on bats advocate for the use of a more holistic view in future fragmentation studies.

Dynamic compressive strength and fragmentation in sedimentary and metamorphic rocks

Brittle deformation at high strain rates results in intense fragmentation and rock pulverisation. For rocks, the critical strain rate at which this behaviour occurs is ~102 s−1. The mechanical properties of rocks at these strain rates can also be very different from their quasi-static properties. Deformation of rocks at these strain rates can occur during fault rupture, landslide events, and meteorite impacts. In this study, we present the results of high strain rate mechanical tests to determine the characteristic strain rate for rate-dependent brittle failure, and the fragment size and shape distributions that result from failure at these conditions. We investigated sandstone, quartzite, limestone, and marble and considered whether the fragment characteristics can be used as diagnostic indicators of loading conditions during brittle failure. We find that the characteristic strain rates, where the dynamic strength is twice the quasi-static strength, range between ~150 and 300 s−1 for rate-dependent brittle failure in the investigated lithologies. Furthermore, we use our results to demonstrate an empirical inverse power-law relationship between fragment size and strain rate for dynamic failure under uniaxial compression. On the other hand, we show that fragment shape is independent of strain rate under dynamic uniaxial loading.

Evaluation of microplastic pollution in Shihezi city, China, using pine needles as a biological passive sampler

Microplastic (MP) pollution has attracted much attention. To understand the characteristics of atmospheric MP pollution in Shihezi, Northwest China, this study used pine needles from trees in Shihezi City as passive samplers. MP contamination was found in all pine needle samples, with an average concentration of 16.52 ± 3.76 items/g. MPs were mainly in the shape of fragments (<0.05 mm). Differences in MP pollution were observed in different functional areas. The abundance of MPs in pine needles was the highest on the main traffic road (19.02 ± 2.52 items/g). Spectral analysis showed that the main polymer of MPs was polyethylene (17.2%), followed by polystyrene (15.5%) and polypropylene (13.8%). By analyzing the principal components and spatial distribution, fragments and pellets were found to have similar sources (mainly industrial activities), whereas films and fibers were influenced by traffic flow. The source of films was related to the packaging industry. The purpose of this study was to provide a reference for the future use of pine needles as atmospheric MP passive samplers, for the traceability and prevention of urban atmospheric MP pollution and for the formulation of national atmospheric MP environmental standards.

Microplastic contamination in lacustrine sediments in the Qinghai-Tibet Plateau: Current status and transfer mechanisms

This paper aims to investigate the present situation and transfer mechanisms of microplastics in lacustrine sediments in the Qinghai-Tibet Plateau. The study surveyed the average abundance of microplastics in sediments. The abundance of microplastics in sediments of lakes from the Qinghai-Tibet Plateau is 17.22–2643.65 items/kg DW and 0–60.63 items/kg DW based on the data of the Qinghai Lake and the Siying Co Basin. The microplastic abundance in sediments from small and medium lakes is very high compared to that in other areas in the world. Like microplastics in other lakes of the world, those in the lakes in the Qinghai-Tibet Plateau mainly include organic polymers PA, PET, PE, and PP and are primarily in the shape of fibers and fragments. The microplastic pollution of lacustrine sediments in the Qinghai-Tibet Plateau is affected by natural changes and by human activities, and the concentration of microplastics in lacustrine ecosystems gradually increases through food chains. Furthermore, the paper suggests the relevant administrative departments of the Qinghai-Tibet Plateau strengthen waste management while developing tourism and pay much attention to the impacts of microplastics in water environments. This study provides a reference for preventing and controlling microplastic contamination in the Qinghai-Tibet Plateau.©2022 China Geology Editorial Office.