Edge effects resulting from adjacent land uses are poorly understood in agroecosystems yet understanding above and belowground edge effects is crucial for maintaining ecosystem function. The aim of ...our study was to examine impacts of land management on aboveground and belowground edge effects, measured by changes in plant community, soil properties, and soil microbial communities across agroecosystem edges. We measured plant composition and biomass, soil properties (total carbon, total nitrogen, pH, nitrate, and ammonium), and soil fungal and bacterial community composition across perennial grassland-annual cropland edges. Edge effects due to land management were detected both aboveground and belowground. The plant community at the edge was distinct from the adjacent land uses, where annual, non-native, plant species were abundant. Soil total nitrogen and carbon significantly decreased across the edge (P < 0.001), with the highest values in the perennial grasslands. Both bacterial and fungal communities were different across the edge with clear changes in fungal communities driven directly and indirectly by land management. A higher abundance of pathogens in the more heavily managed land uses (i.e. crop and edge) was detected. Changes in plant community composition, along with soil carbon and nitrogen also influenced the soil fungal community across these agroecosystems edges. Characterizing edge effects in agroecosystem, especially those associated with soil microbial communities, is an important first step in ensuring soil health and resilience in these managed landscapes.
Soil invertebrates are an integral part of Arctic ecosystems through their roles in the breakdown of litter, soil formation, and nutrient cycling. However, studies examining soil invertebrates in the ...Arctic are limited and our understanding of the abiotic and biotic drivers of these invertebrate communities remains understudied. We examined differences in soil invertebrate taxa (mites, collembolans, enchytraeids) among several undisturbed upland tundra heath sites in Nunavut Canada and identified the drivers (vegetation and substrate cover, soil nutrients and pH) of the soil invertebrate community across these sites. Soil invertebrate densities were similar to that of other Arctic studies. While invertebrate communities were relatively consistent between our sites, cover of rocks, woody litter, and the lichen Alectoria nigricans had significant, positive influences on the density of all invertebrates studied. Mites and collembolans were more closely associated with cover of lichens, whereas enchytraeids were more closely associated with woody litter and rocks. Our results suggest that anthropogenic (e.g., resource exploration and extraction) and/or natural (e.g., climate change) disturbances that result in changes to the vegetation community and woody litter inputs will likely impact soil invertebrates and the ecosystem services they provide.
The emerging work on understanding open source software has questioned what leads to effectiveness in OSS development teams in the absence of formal controls, and it has pointed to the importance of ...ideology. This paper develops a framework of the OSS community ideology (including specific norms, beliefs, and values) and a theoretical model to show how adherence to components of the ideology impacts effectiveness in OSS teams. The model is based on the idea that the tenets of the OSS ideology motivate behaviors that enhance cognitive trust and communication quality and encourage identification with the project team, which enhances affective trust. Trust and communication in turn impact OSS team effectiveness. The research considers two kinds of effectiveness in OSS teams: the attraction and retention of developer input and the generation of project outputs. Hypotheses regarding antecedents to each are developed. Hypotheses are tested using survey and objective data on OSS projects. Results support the main thesis that OSS team members' adherence to the tenets of the OSS community ideology impacts OSS team effectiveness and reveal that different components impact effectiveness in different ways. Of particular interest is the finding that adherence to some ideological components was beneficial to the effectiveness of the team in terms of attracting and retaining input, but detrimental to the output of the team. Theoretical and practical implications are discussed.
Diversity is a defining characteristic of global collectives facilitated by the Internet. Though substantial evidence suggests that diversity has profound implications for a variety of outcomes ...including performance, member engagement, and withdrawal behavior, the effects of diversity have been predominantly investigated in the context of organizational workgroups or virtual teams. We use a diversity lens to study the success of nontraditional virtual work groups exemplified by open source software (OSS) projects. Building on the diversity literature, we propose that three types of diversity (separation, variety, and disparity) influence two critical outcomes for OSS projects: community engagement and market success. We draw on the OSS literature to further suggest that the effects of diversity on market success are moderated by the application development stage. We instantiate the operational definitions of three forms of diversity to the unique context of open source projects. Using archival data from 357 projects hosted on SourceForge, we find that disparity diversity, reflecting variation in participants' contribution-based reputation, is positively associated with success. The impact of separation diversity, conceptualized as culture and measured as diversity in the spoken language and country of participants, has a negative impact on community engagement but an unexpected positive effect on market success. Variety diversity, reflected in dispersion in project participant roles, positively influences community engagement and market success. The impact of diversity on market success is conditional on the development stage of the project. We discuss how the study's findings advance the literature on antecedents of OSS success, expand our theoretical understanding of diversity, and present the practical implications of the results for managers of distributed collectives.
Trust Transfer on the World Wide Web Stewart, Katherine J
Organization science (Providence, R.I.),
01/2003, Volume:
14, Issue:
1
Journal Article
Peer reviewed
The World Wide Web (WWW) has been touted as providing great opportunities for small businesses to compete and thrive. Concerns about trust have been identified as a barrier to such businesses' ...success. This research explores how consumers' initial trust judgments about organizations they encounter on the Web may be influenced by hypertext links from trusted websites and associations with the more trust-inducing traditional retail channel. This paper develops and tests a cognitive model of the trust transfer process, arguing that trust is transferred across hypertext links based on the perceived interaction and similarity of the linked organizations, and that institution-based trust is transferred from the traditional shopping channel to a Web-based organization based on evidence that the Web-based organization has a physical store. An experimental study shows that a hypertext link from one website to another increased the extent to which the linked organizations were perceived to have a business relationship and be similar, and these perceptions had a positive influence on trusting beliefs regarding the linked site. Associating with the physical shopping channel by showing a picture of a building on a website increased the extent to which subjects reported intention to buy from the site. The study provided empirical evidence that trusting beliefs regarding the website had a significant positive effect on intention to buy from it. This paper discusses further development of the trust transfer model based on the social perception literature and explores implications for future research.
The human lung differs substantially from its mouse counterpart, resulting in a distinct distal airway architecture affected by disease pathology in chronic obstructive pulmonary disease. In humans, ...the distal branches of the airway interweave with the alveolar gas-exchange niche, forming an anatomical structure known as the respiratory bronchioles. Owing to the lack of a counterpart in mouse, the cellular and molecular mechanisms that govern respiratory bronchioles in the human lung remain uncharacterized. Here we show that human respiratory bronchioles contain a unique secretory cell population that is distinct from cells in larger proximal airways. Organoid modelling reveals that these respiratory airway secretory (RAS) cells act as unidirectional progenitors for alveolar type 2 cells, which are essential for maintaining and regenerating the alveolar niche. RAS cell lineage differentiation into alveolar type 2 cells is regulated by Notch and Wnt signalling. In chronic obstructive pulmonary disease, RAS cells are altered transcriptionally, corresponding to abnormal alveolar type 2 cell states, which are associated with smoking exposure in both humans and ferrets. These data identify a distinct progenitor in a region of the human lung that is not found in mouse that has a critical role in maintaining the gas-exchange compartment and is altered in chronic lung disease.
Understanding kidney disease relies on defining the complexity of cell types and states, their associated molecular profiles and interactions within tissue neighbourhoods
. Here we applied multiple ...single-cell and single-nucleus assays (>400,000 nuclei or cells) and spatial imaging technologies to a broad spectrum of healthy reference kidneys (45 donors) and diseased kidneys (48 patients). This has provided a high-resolution cellular atlas of 51 main cell types, which include rare and previously undescribed cell populations. The multi-omic approach provides detailed transcriptomic profiles, regulatory factors and spatial localizations spanning the entire kidney. We also define 28 cellular states across nephron segments and interstitium that were altered in kidney injury, encompassing cycling, adaptive (successful or maladaptive repair), transitioning and degenerative states. Molecular signatures permitted the localization of these states within injury neighbourhoods using spatial transcriptomics, while large-scale 3D imaging analysis (around 1.2 million neighbourhoods) provided corresponding linkages to active immune responses. These analyses defined biological pathways that are relevant to injury time-course and niches, including signatures underlying epithelial repair that predicted maladaptive states associated with a decline in kidney function. This integrated multimodal spatial cell atlas of healthy and diseased human kidneys represents a comprehensive benchmark of cellular states, neighbourhoods, outcome-associated signatures and publicly available interactive visualizations.
Indigenous nations worldwide are working with and lobbying private and public resource developers to ensure meaningful engagement in decisions tied to resource development in their territories. The ...diversity of approaches for engagement can be framed along a continuum, with voluntary practices at one end and legal responsibilities at the other. Given this continuum, the roles and responsibilities of various actors involved have become blurred, which leads to poor practice. In an effort to bring clarity, the aim of this research was to understand the distinctions between voluntary practices and legal responsibilities among key actors, identify how key actors understood their different roles and responsibilities, and explain the implications of these differences. In partnership with a First Nation and a public power utility in Northern Saskatchewan, Canada, we employed semi-structured interviews and group workshops with Indigenous, industry, and government actors who participate in environmental management and resource development decisions. We found that actors had distinct motivations for interacting with one another, that perceptions of voluntary practices and legal responsibilities aligned among some participants but not among others, and that participants were indeed confused about their roles and responsibilities in relation to legal requirements and voluntary engagement activities. Furthermore, we learned that clarifying the intended roles of those involved in resource development decisions would be insufficient for improving practice. This is because improved clarity may not address underlying mistrust of government by Indigenous people, or may not be possible where rights and interests are intertwined under a broad conception of Indigenous rights. Findings also suggest the need for government and industry to work with Indigenous nations as self-determining entities, rather than imposing unilateral processes upon them. Consequently, more serious scrutiny, understanding and action is needed by government and industry when employing and assessing voluntary actions and legal measures for Indigenous inclusion in resource development decision-making processes.
•Legal-voluntary continuum explains Indigenous participation in resource development•Motivations differ for collaboration among actors in resource development decisions•Ambiguity in definitions, roles and responsibilities complicate decision-making•Existing processes for Indigenous engagement and consultation need improvement•Clarification of roles and responsibilities is insufficient to improve processes
Identifying the key drivers of nitrogen cycling processes that influence gaseous N exchanges in arctic ecosystems is essential for predicting the response of northern systems to changes in climatic ...conditions. In this review we examine pathways of N input (atmospheric N deposition and biological N2-fixation), cycling (N mineralization, immobilization and nitrification) and output (denitrification and nitrifier denitrification) found across the Arctic with a focus upon gaseous N exchanges in these ecosystems. Cyanobacteria are ubiquitous in the Arctic where they can be found in association with lichen or bryophytes and also as free-living components of biological soil crusts. N2-fixation by cyanobacteria in arctic ecosystems provides significant landscape-scale N inputs, and is an important N source for annual plant N uptake. The activity and extent of these cyanobacterial associations is driven primarily by moisture gradients associated with topography that determine nutrient availability. N2-fixation rates tend to be highest in relatively low topographical or microtopographical positions that are associated with soils of higher total N, mineralizable N, total carbon and organic carbon compared to higher topographical positions. Topography is also a key landscape-level driver of N mineralization, nitrification and denitrification processes through its control on factors such as soil moisture, soil temperature and nutrient availability. In general, while N mineralization rates are also higher in relatively low topographical or microtopographical positions, net nitrification and immobilization tend to be inhibited in these locations. This higher mineralization is linked to relatively high N2O emissions in lower lying areas in arctic landscapes since moisture and NH4 levels tend to be higher in those locations and are important controls on denitrification and nitrifier denitrification respectively. These soil topographical controls are modulated by arctic plants which may also have a direct, light-dependent role in N2O emissions, and undoubtedly play important indirect roles in gaseous N cycling via evapotranspiration effects. Our review indicates that arctic microscale and field topographic variation dominate patterns of atmospheric N inputs and losses in arctic ecosystems. However, further studies are needed to provide a better understanding of the associated driving factors on the multitude of processes that influence gaseous N exchange.
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•We examine pathways of atmospheric N input and output across the Arctic.•Arctic microscale and field topography dominate patterns of atmospheric N exchange.•Topography establishes gradients in resource availability influencing N transformations.•Predicting arctic response to climate changes requires knowledge of nitrogen cycling processes.
