Structure Patterns Research Articles

Physicochemical characteristics and oxidative potential of size-segregated respirable coal mine dust: Implications for potentially hazardous agents and health risk assessment

The health risks associated with exposure to respirable dust in coal mines have been attracted much attention by an increasing number of researchers. However, the accurate identification of potentially hazardous agents in respirable dusts and the evaluation of the potential health risks arising from it still remains controversial to varying degrees. A comprehensive understanding of the physicochemical properties of respirable dust is a prerequisite and an important basis for resolving this controversy. Therefore, in this study, the particle size distribution and morphology, pore structure, mineralogical and geochemical patterns, and oxidative potential (OP) of respirable coal mine dust were comprehensively investigated. Stepwise multiple linear regression was employed to identify dust components driving OP, such as anatase, tobelite, quartz, and ankerite, in respirable coal mine dust, along with Na, Ni, Se, W, and As. On this basis, we performed a single-factor risk prediction for different coal mines by considering factors that may impact miners' health, with the analyses yielding somewhat contradictory results. Therefore, a multifactor integrated prediction model is proposed using an entropy-based technique for order preference by similarity to the ideal solution to categorize coal mines in the study area into three risk categories, high-, medium-, and low-risk dust mines, which is important for the hierarchical classification and control of coal mines and for formulating appropriate dust prevention and control measures.

Same places, same stories? Genomics reveals similar structuring and demographic patterns for four Pocillopora coral species in the southwestern Indian Ocean

AbstractAimEfficiently protecting species requires knowing their ecological, life‐history and reproductive traits. This is particularly decisive for scleractinian corals, key components of coral reefs, which are experiencing critical declines. Yet their connectivity remains insufficiently documented. Here, we focused on four distinct species of the coral genus Pocillopora found in diverse habitats of the southwestern Indian Ocean and presenting various reproductive strategies. We aimed to understand whether these traits affect species connectivity.LocationArchipelagos and islands of the southwestern Indian Ocean.TaxonPocillopora spp.MethodsWe used target capture to collect single‐nucleotide polymorphisms (SNPs) from over a thousand colonies sampled across nine localities. From the ca. 1400 SNPs retained per species, Bayesian clustering methods, networks and demographic inferences were applied to first infer the population genetic structure and connectivity of each species, then the demographic history of each population.ResultsAll four Pocillopora species exhibited almost the same genetic structuring pattern, reflecting the sampled ecoregions (Madagascar and surrounding islands vs. Mascarene Islands). However, the genetic differentiation was stronger (FST about 10 times higher) for P. acuta, the species inhabiting more enclosed habitats, such as lagoons and shallow waters, and reproducing mainly asexually. Similarly, all populations, except those from P. acuta, showed a signature of population expansion ca. 100,000 years ago, following the penultimate glacial period.Main ConclusionsThese results indicate reduced gene flow between Madagascar and the Mascarene Islands, probably linked to currents, suggesting distinct connectivity networks that should be considered independently when setting up conservation plans. In addition, shared demographic histories reflect that populations from these species have probably met the same environmental constraints and reacted similarly, something that should be considered in light of the ongoing rapid climate change.

Unravelling the cavity‐nesting network at large spatial scales: The biogeographic role of woodpeckers as ecosystem engineers

AbstractAimPrimary cavity nesters (e.g. woodpeckers) act as ecosystem engineers by providing tree cavities to several vertebrates that use them as nests or refuges. Although diverse assemblages of primary excavators are assumed to increase the number of tree cavities, environmental factors can limit populations of primary excavators, thus weakening their ecological function. We aim to test the biogeographical‐scale relationships between primary excavators and cavity users by distinguishing the contribution of environmental variables.LocationSouthern South America.Materials and MethodsWe used species distribution models, which combine bioclimatic and remote sensing derived variables, to map the richness of vertebrates composing the cavity‐network of temperate and Mediterranean forests of South America. Based on a resampling procedure for ensuring spatial independence, we fitted structural equation models to estimate relationships between forest characteristics and cavity user vertebrates.ResultsRichness of secondary cavity users (mammals, obligated, habitat generalists and forest specialists) were positively and strongly influenced by the richness of primary excavators. Environmental variables affected differently the richness of primary and secondary cavity users. The richness of primary cavity users responded to tree richness and height while that of habitat specialist secondary users was positively affected by primary productivity and negatively by sclerophyll forests.Main ConclusionsOur results confirm the role of primary excavators as ecosystem engineers but highlight the importance of considering large spatial scales when analysing cavity‐nesting networks. Biogeographical patterns of tree diversity and forest structure can be important drivers of cavity nesting networks that remain hidden when studies are conducted over fine spatial scales.

Genome-wide identification and expression analysis of the glutamate receptor gene family in sweet potato and its two diploid relatives.

Plant glutamate receptor (GLR) homologs are crucial calcium channels that play an important role in plant development, signal transduction, and response to biotic and abiotic stresses. However, the GLR gene family has not yet been thoroughly and systematically studied in sweet potato. In this study, a total of 37 GLR genes were identified in the cultivated hexaploid sweet potato (Ipomoea batatas), and 32 GLR genes were discovered in each of the two diploid relatives (Ipomoea trifida and Ipomoea triloba) for the first time. Based on their evolutionary relationships to those of Arabidopsis, these GLRs were split into five subgroups. We then conducted comprehensive analysis to explore their physiological properties, protein interaction networks, promoter cis-elements, chromosomal placement, gene structure, and expression patterns. The results indicate that the homologous GLRs of the cultivated hexaploid sweet potato and its two relatives are different. These variations are reflected in their functions related to plant growth, hormonal crosstalk, development of tuberous roots, resistance to root rot, and responses to abiotic stress factors, all of which are governed by specific individual GLR genes. This study offers a comprehensive analysis of GLR genes in sweet potato and its two diploid relatives. It also provides a theoretical basis for future research into their regulatory mechanisms, significantly influencing the field of molecular breeding in sweet potatoes.

How does industrial transformative process shape the spatial dynamics of urban development?

Rapid global expansion of built-up areas and industrialization has led to significant environmental challenges, particularly in terms of anthropogenic carbon emissions. Consequently, it has become crucial to comprehensively understand the spatial dynamics of urban built-up areas and the associated socioeconomic transitions. This understanding serves as a critical foundation for formulating effective land use and industrial policies that not only promote economic sustainability but also contribute to the pursuit of environment related- sustainable development goals (SDGs). However, our knowledge about the dynamic relationship between urban industrial structure and built-up area patterns is limited. To address this gap, we use partial redundancy analysis (PRDA) to quantify the relative impact of key industrial employment sectors. The results indicate that the transformation of industrial structure has a significant influence on the spatial dynamics and morphologies of urban built-up areas. In addition, we found that the decline in agricultural population is associated with an increase in spatial isolation, while the growth of the manufacturing population affects changes in spatial extent and regularity. Furthermore, the combined impact of industrial and economic drivers accounts for up to 24.4% of the dynamics of urban built-up areas, with industrial transformation having a 3.82% greater impact than economic growth. These findings provide a valuable understanding of the interconnectedness between the spatial evolution of built-up areas and socioeconomic transitions, not only in China but also in other city clusters worldwide. Moreover, they might contribute to the knowledge of carbon neutrality pathways, further promoting sustainable development efforts.

Metallurgical Analysis in the Outer Tube Fault Area

In the automotive manufacturing industry, product failures are still found. In this study, one of the automotive components, namely the outer tube of the motorcycle front fork, was cracked. The outer tube is part of the shock absorber component which is also connected to the motorcycle steering system. Failure analysis aims to obtain some data or facts that can indicate the root cause of the failure or failure. Sample preparation which includes the process of selecting the cut area, cleaning and cutting for the fractography process. As for metallography, sample preparation is continued with the process of mounting, sanding, polishing and etching. Fractographic test showed that the fracture occurred in a brittle fracture mode, with no traces of plastic deformation. The morphology of the fracture surface also shows the presence of gas trapped in large quantities. In the metallographic test, the overall microstructure shows an eutectic phase with a uniform dendrite structure pattern, this indicates that metal solidification occurs quite quickly and can cause a lot of gas to be trapped in the metal characterized by the presence of multiple porosities. This can provide an indication of the relationship between the microstructure and the fracture surface morphology. Cracking and brittle fracture can be caused by the stress that occurs in the metal that exceeds the yield and plastic limits due to the large pressure of gas trapped in the metal.

Structure and labor use pattern among cocoa farmers in Ondo State, Nigeria

Human labour is about the only main source of labour available to smallholder farmers in Nigeria. Smallholder farmers contribute over 85% of domestic agricultural output in Nigeria, hence, human labour accounts for the domestic food supply in Nigeria. Therefore, the need to continue supplying food for the ever-growing Nigerian population anchors on human labour productivity. In Nigerian agriculture, hired labour is predominantly used. Human labour plays a very significant role in agricultural development, especially in developing countries where technological development is still very low. In view of the importance of labour in agricultural production, this study was designed to investigate the structure and use pattern of farm labour in the study area. The study was carried out in Ondo state, Nigeria. A multistage sampling technique was used to collect data from 160 farmers. After sorting for missing data, 144 cocoa farmers’ data were used for analysis in this study. Seventy-five percent of the total
 respondents were above 50 years of age and about 25.01% of the total respondents were 50 years and below. The majority (79.17%) of the farmers were men. Also, 75.07% of the respondents had a formal level of education. In the study contract type of labour is majorly used for most activities in cocoa farming while cooperative labour was seldom used. Activities such as land clearing (75.0%), planting (83.32%), weeding (95.83%), application of chemicals (91.67%), removal of mistletoes (87.50%), harvesting of cocoa pods (87.50%), conveyance of cocoa pods to the pod breaking point (95.83%), breaking of cocoa pods (100%) and conveyance of cocoa beans to the point of fermentation (88.33%) were majorly carried out by contract labour. Male labour was mostly utilized for all the activities as indicated by most farmers. Female labour was sparingly utilized for some activities such as land clearing (8.33%), planting (0%), application of chemicals (8.33%), spraying of chemicals (4.17%), removal of mistletoes (0%) and harvesting of cocoa pods (12.5%). The study recommended that funds should be made available to farmers to engage in contract labour and also there should be the need to use equipment and machinery to reduce drudgery.

On conservation of world heritage Beijing-Hangzhou grand canal for enhancing cultural ecosystem services

The Beijing-Hangzhou Grand Canal carries unique social and cultural significance as a world cultural heritage, but with the acceleration of global urbanization, it has potentially severe environmental risks under continuous anthropogenic disturbances. Therefore, to protect the ecological and cultural values of the Grand Canal, it is necessary to assess the corresponding relationship of water quality to land use and the perception of ecosystem services that focus on cultural ecosystem services (CES). This study aims to analyze the water quality response to land use in the Beijing-Hangzhou Grand Canal, describe the land use types closely related to water quality, and propose corresponding management strategies for enhancing CES. This study investigated the impacts of land use structure and landscape pattern on water quality by calculating the correlation between land use structure and landscape pattern indices and water quality in buffer zones of different distances on both sides of the canal. The results show that green land dominates the land use structure and can effectively reduce water pollution in the canal. On the other hand, urban impervious surfaces showed a significant positive correlation with pollution contributing to low water quality. We accessed the impact of water quality on the perception of CES in the Beijing-Hangzhou Grand Canal and proposed optimization strategies for promoting CES. Both content analysis and thematic analysis were applied to analyze the impact of the water environment quality of the Beijing-Hangzhou Grand Canal on the perception of CES. We found that the perceptions of CES along the Beijing-Hangzhou Grand Canal are associated with the public’s opinions on its cultural heritage services and artistic inspiration services. The perceptions of CES are closely related to the quality of the water environment and riparian greenness, which affect the values of cultural heritage and conservation of the Beijing-Hangzhou Grand Canal.

Enantiomorph conversion in single crystals of the Weyl semimetal CoSi

Chiral intermetallic phases may show unusual chemical and physical properties with nontrivial structure-property relationship. It is therefore of particular interest to study the structural conversion between domains of different handedness. Here, the atomic decoration of the enantiomorph exchange area within single crystal of the Weyl semimetal CoSi is determined by a combination of atomic-resolution scanning transmission electron microscopy imaging, single crystal X-ray diffraction and quantum chemical analysis of atomic interactions. Two-atomic [CoSi] units are shown to be the bonding base for the FeSi-type structure and may be considered as ‘pseudo-molecules’, thinking of molecular organic crystals. Tiny reorganisation of atomic interactions within these units results in the appearance of sequence ‘faults’ in the structure pattern i.e. in a different structural motif in the enantiomorph exchange area, which – contrary to the A and B enantiomorphs of CoSi – contains an inversion centre and allows a local enantiomorph ‘conversion’. Due to the special features of atomic interactions, the reorganisation of multi-atomic bonds leads to slightly higher total energy. This appears within one and the same grain which is prepared by the short distance chemical vapor transport.

No evidence for fractal scaling in canopy surfaces across a diverse range of forest types

Abstract Canopy structural complexity is a key emergent property of forest ecosystems that directly relates to their ability to store carbon, cycle water and nutrients, and provide habitat for biodiversity. However, we lack a general framework for quantifying the structural complexity of forest canopies, and it remains to be seen if there are simple rules that explain the huge variation in canopy structure that we observe across the world's forests. A leading candidate for characterizing differences in structural complexity among forest ecosystems are fractal scaling laws, or measures of statistical self‐similarity. If forest canopies were fractal in nature, their structural attributes could be distilled into a single coefficient—their fractal dimension—which could then be used to directly compare structural differences within and across biomes. To test this idea, we used airborne laser scanning (ALS) data acquired across nine landscapes in Australia that span a huge environmental gradient and include everything from dry shrublands, tropical savannas, dense rainforests, to 90 m tall Mountain Ash forests. Using the ALS data, we built high‐resolution 3D canopy height models of each landscape so that we could quantify how closely they followed fractal scaling laws, based on a comprehensive set of fractal dimension estimators. Across all ecosystem types, fractal scaling assumptions were consistently violated, with clear and systematic differences between real‐world forest canopies and simulated fractal surfaces. However, deviations from fractality did vary predictably among sites, with forests in less arid environments, dominated by tall trees with large crowns, exhibiting a higher degree of self‐similarity across scales. Synthesis: Our study conclusively shows that canopy surfaces are not fractal beyond the scale of individual tree crowns. Nevertheless, we still observed ecologically meaningful and generalisable patterns in forest structure across scales, which closely reflect biophysical and physiological constraints on tree size and architecture. These patterns point the way towards a more general framework for characterizing ecological complexity.

Пилотные инновационные территориальные кластеры: пространственная дифференциация, закономерности развития и эффективность

The article is devoted to the study of an important component of innovative infrastructure – pilot innovative territorial clusters. The mainstages of their formation wereconsidered,spatial patterns of development,structure and economic efficiency were identified and analyzed. The purpose of the study is to analyze the spatial regularities of pilot innovative territorial clusters functioning to justify the promising directions of the state cluster policy contributing to the effective use of the financial resources of the federal budget by determining priority investment directions and establishing on this basis the recipients of state support in the cluster with the greatest potential in the context of limited financial resources. This is promising primarily for justifying the stimulation of new high-tech industries and enterprises. The study was carried out on the basis of materials from official federal and regional statistics, information and analytical reports of the Association of Clusters, Technoparks and SEZs of Russia, official ratings of regions innovative development, legislative acts of the federal and regional levels. Patterns of functioning and trends in the development of innovative territorial clusters have been identified. The main purpose of the emerging innovative territorial clusters is to saturate the huge domestic market with high-tech goods, services and technologies in order to achieve the country’s technological independence. Promising directions for improving the cluster policy of Russia are formulated.

Medical-Radiation-Shielding Film Fabricated by Imitating the Layered Structure Pattern of Abalone Shell and Verification of Its Shielding Effect.

Radiation-shielding clothing for medical workers must be light and thin, thus ensuring flexibility. However, controlling the thickness and weight is limited by shielding performance requirements. This study aims to improve shielding performance by considering a shielding structure that mimics the internal structure of an abalone shell. Two shields were produced: a sheet made with a carrier process using a liquid polymer and tungsten mixture, and a fillet made by compounding the same material and laminated using a heat-treatment press after the injection process. The tungsten content and thickness were the same at 85 wt% and 0.3 mm, respectively. In the high-energy region, the shielding film based on the laminated structure of abalone shells showed a shielding rate that was higher by more than 7%. Compared to that of a 0.3 mm lead plate, the shielding ratio of the shielding film was approximately 16% lower at 120 kVp, thereby confirming the radiation-shielding effect of the layered-structure shielding film. Therefore, it is concluded that the laminated structure of the shielding film, which is identical to the internal laminated structure of the abalone shell, expands the impact area of incident radiation and attenuates the energy intensity, thereby improving the medical-radiation-shielding performance.

Increasing Regional Economic Value from Coastal Reclamation Development

This study aims to understand changes in spatial structure and spatial patterns in the coastal area in the Makassar urban system due to land use conversion. This study uses a qualitative approach by collecting data through observation, visual analysis, literature study, interviews, and documentation. The results of the study show that changes in spatial use in the Center Point of Indonesia area have led to the marginalization of local communities. Intensive land conversion has changed the work system of local communities, replacing them with the urban industrial community work system. The orientation of the development of the Center Point of Indonesia area is to create business opportunities for people engaged in the informal sector, tourism, transportation, and other service sectors, as well as create a friendly and modern environmental area. Overall, this beach reclamation has a positive impact on the environment that is sustainable and provides business opportunities and increased income for the community.

Real-time prediction of ship motion based on improved empirical mode composition and dynamic residual neural network

Ship motion attitude data have strong random and non-stationary characteristics under severe sea states. Real-time and accurate prediction of the ship's motion attitude can significantly improve the safety of navigation. Therefore, this article proposes a prediction model based on the improved empirical mode decomposition (IEMD) and the dynamic residual recurrent neural network with bidirectional structure and time pattern attention mechanism (TPA-Bi-DRRNN), and proposes a new algorithm: dynamic adaptive beetle swarm antennae search (DABSAS) algorithm to optimise the initial weight and threshold of the prediction model. The input data are adaptively composed into multiple intrinsic mode functions (IMFs) containing their frequency characteristics using IEMD, and a prediction is made for each IMF using TPA-Bi-DRRNN. The model structure can be regulated in real time according to the sliding window. The destroyer DTMB5415 is used as an example to conduct a performance test of the hybrid prediction model and DABSAS. The results show that no mode mixing occurred in the IMFs, the noise in each IMF was significantly reduced, thus dramatically reducing the difficulty of using the input data for prediction; and the optimization performance of DABSAS in applying the TPA-Bi-DRRNN is much better than that of the traditional algorithms. Compared with other models, the difference in the predictive accuracy of TPA-Bi-DRRNN under each condition is the smallest, suggestings that it has extremely high robustness and will always be able to maintain much higher accuracy than other models over a long period, thus meeting the needs for real-time accurate prediction of ship motion attitude.

Reference genome of Townsend's big-eared bat, Corynorhinus townsendii.

Townsend's big-eared bat, Corynorhinus townsendii, is a cave- and mine-roosting species found largely in western North America. Considered a species of conservation concern throughout much of its range, protection efforts would greatly benefit from understanding patterns of population structure, genetic diversity, and local adaptation. To facilitate such research, we present the first de novo genome assembly of C. townsendii as part of the California Conservation Genomics Project (CCGP). Pacific Biosciences HiFi long reads and Omni-C chromatin-proximity sequencing technologies were used to produce a de novo genome assembly, consistent with the standard CCGP reference genome protocol. This assembly comprises 391 scaffolds spanning 2.1 Gb, represented by a scaffold N50 of 174.6 Mb, a contig N50 of 23.4 Mb, and a benchmarking universal single-copy ortholog (BUSCO) completeness score of 96.6%. This high-quality genome will be a key tool for informed conservation and management of this vulnerable species in California and across its range.

Revisiting Oligo-Miocene epoch through the altitudinal patterns study of plant species and phylogenetic diversity of Mt. Elgon in Africa

The variation in patterns of plant species distribution has been of interest to naturalists and ecologists. However, African mountains remain nature's laboratories least explored. This study aims to identify the altitudinal pattern of plant taxonomic and phylogenetic diversity, and community structure of Mt. Elgon, which is an isolated ancient volcanic mountain of the Oligocene-Miocene epoch in Africa, hosting a rare species pool. Species diversity data (1606 species) was obtained through random walk field surveys, herbaria collections and online databases. We calculated Faiths’ phylogenetic diversity and its standard effect size (SES_PD), net related index (NRI) and nearest taxon index (NTI) among its four vegetation zones, six habitats and 28–100m elevation bands. Our results indicated that herbaceous plants had higher species richness than woody plants and they both assumed a monotonic decline pattern among vegetation zones, and a hump shaped pattern among habitats and 100m elevation bands. However, standardized phylogenetic diversity and structure (SES_PD, NTI and NRI) pattern differed and fluctuated between woody and herbaceous plants demonstrating a zigzag pattern. Mid-elevation phylogenetic overdispersion structure was observed based on NRI (clade level), while phylogenetic clustering progressively increased with elevation in NTI (taxon level). The complex phylogenetic diversity and structure in this study indicate a unique ecosystem worth conservation and more scientific exploration. Consequently, we recommend regions of phylogenetic overdispersion structure for priority conservation.

Tooth pattern, development, and replacement in the yellow catfish, Pelteobagrus fulvidraco

AbstractStudies of teleost teeth are important for understanding the evolution and mechanisms of tooth development, replacement, and regeneration. Here, we used gross specimens, microcomputed tomography, and histological analysis to characterize tooth structure, development, and resorption patterns in adult Pelteobagrus fulvidraco. The oral and pharyngeal teeth are villiform and conical. Multiple rows of dentition are densely distributed and the tooth germ is derived from the epithelium. P. fulvidraco exhibits a discontinuous and non‐permanent dental lamina. Epithelial cells surround the teeth and are separated into distinct tooth units by mesenchymal tissue. Tooth development is completed in the form of independent tooth units. P. fulvidraco does not undergo simultaneous tooth replacement. Based on tooth development and resorption status, five forms of teeth are present in adult P. fulvidraco: developing tooth germs, accompanied by relatively immature tooth germs; mature and well‐mineralized tooth accompanied by one tooth germ; teeth that have begun resorption, but not completely fractured; fractured teeth with only residual attachment to the underlying bone; and teeth that are completely resorbed and detached. Seven biological stages of a tooth in P. fulvidraco were also described.

Embedded macrophages induce intravascular coagulation in 3D blood vessel-on-chip

Macrophages are innate immune cells that prevent infections and help in wound healing and vascular inflammation. While these cells are natural helper cells, they also contribute to chronic diseases, e.g., by infiltrating the endothelial layer in early atherosclerosis and by promoting vascular inflammation. There is a crosstalk between inflammatory pathways and key players in thrombosis, such as platelets and endothelial cells – a phenomenon known as ‘thromboinflammation’. The role of the embedded macrophages in thromboinflammation in the context of vascular disease is incompletely understood. Blood vessels-on-chips, which are microfluidic vascular cell culture models, have been used extensively to study aspects of vascular disease, like permeability, immune cell adhesion and thrombosis. Blood perfusion assays in blood vessel-on-chip models benefit from multiple unique aspects of the models, such as control of microvessel structure and well-defined flow patterns, as well as the ability to perform live imaging. However, due to their simplified nature, blood vessels-on-chip models have not yet been used to capture the complex cellular crosstalk that is important in thromboinflammation. Using induced pluripotent stem cell-derived endothelial cells and polarized THP-1 monocytes, we have developed and systematically set up a 3D blood vessel-on-chip with embedded (lipid-laden) macrophages, which is created using sequential cell seeding in viscous finger patterned collagen hydrogels. We have set up a human whole blood perfusion assay for these 3D blood vessels-on-chip. An increased deposition of fibrin in the blood vessel-on-chip models containing lipid-laden macrophages was observed. We anticipate the future use of this advanced vascular in vitro model in drug development for early atherosclerosis or aspects of other vascular diseases.Graphical

How Veeries vary: Whole genome sequencing resolves genetic structure in a long-distance migratory bird

Abstract In high-latitude species with high dispersal ability, such as long-distance migratory birds, populations are often assumed to exhibit little genetic structure due to high gene flow or recent postglacial expansion. We sequenced over 120 low-coverage whole genomes from across the breeding range of a long-distance migratory bird, the Veery (Catharus fuscescens), revealing strong evidence for isolation by distance. Additionally, we found distinct genetic structure between boreal, western montane U.S., and southern Appalachian sampling regions. We suggest that population genetic structure in this highly migratory species is detectable with the high resolution afforded by whole-genomic data because, similar to many migratory birds, the Veery exhibits high breeding-site fidelity, which likely limits gene flow. Resolution of isolation by distance across the breeding range was sufficient to assign likely breeding origins of individuals sampled in this species’ poorly understood South American nonbreeding range, demonstrating the potential to assess migratory connectivity in this species using genomic data. As the Veery’s breeding range extends across both historically glaciated and unglaciated regions in North America, we also evaluated whether contemporary patterns of structure and genetic diversity are consistent with historical population isolation in glacial refugia. We found that patterns of genetic diversity did not support southern montane regions (southern Appalachians or western U.S. mountains) as glacial refugia. Overall, our findings suggest that isolation by distance yields subtle associations between genetic structure and geography across the breeding range of this highly vagile species even in the absence of obvious historical vicariance or contemporary barriers to dispersal.

Steps to implementation: the role of peer feedback inner structure on feedback implementation

Though implementing feedback provided by peers has been an essential step for learning efficiency in peer feedback activities, it remains challenging for students. This study aims to explore the inner structure patterns of students’ peer feedback and how they are related to feedback implementation. Sixty-nine engineering students from a Singapore university participated in the peer feedback activity. Content analysis was conducted to analyse the inner structure of feedback as well as the implementation status of each feedback. Sequential mining was applied to investigate the sequential patterns of the various feedback components. The results show a variation of inner structures in the implemented feedback and unimplemented feedback. The implemented feedback tended to be sequenced with an evaluation or a standpoint before seeking clarification or suggestions for improvement. It was also likely to contain continuous questions seeking clarifications. In comparison, the unimplemented feedback was likely to continuously indicate positive evaluations or agreements. By understanding the inner structure of peer feedback with different implementation statuses, researchers and educators can fine-tune design and instructions to support peer feedback practices.