bluuebunny/crossref_metadata_2025_split huggingface dataset:
δ
13
C methane source signatures from tropical wetland and rice field emissions
Authors: France James L. , Fisher Rebecca E. , Lowry David , Allen Grant , Andrade Marcos F. , Bauguitte Stéphane J.-B. , Bower Keith , Broderick Timothy J. , Daly Michael C. , Forster Grant , Gondwe Mangaliso , Helfter Carole , Hoyt Alison M. , Jones Anna E. , Lanoisellé Mathias , Moreno Isabel , Nisbet-Jones Peter B. R. , Oram David , Pasternak Dominika , Pitt Joseph R. , Skiba Ute , Stephens Mark , Wilde Shona E. , Nisbet Euan G. 
Published: December 2021

The atmospheric methane (CH
4
) burden is rising sharply, but the causes are still not well understood. One factor of uncertainty is the importance of tropical CH
4
emissions into the global mix. Isotopic signatures of major sources remain poorly constrained, despite their usefulness in constraining the global methane budget. Here, a collection of new
δ
13
C

CH
4

signatures is presented for a range of tropical wetlands and rice fields determined from air samples collected during campaigns from 2016 to 2020. Long-term monitoring of
δ
13
C

CH
4

in ambient air has been conducted at the Chacaltaya observatory, Bolivia and Southern Botswana. Both long-term records are dominated by biogenic CH
4
sources, with isotopic signatures expected from wetland sources. From the longer-term Bolivian record, a seasonal isotopic shift is observed corresponding to wetland extent suggesting that there is input of relatively isotopically light CH
4
to the atmosphere during periods of reduced wetland extent. This new data expands the geographical extent and range of measurements of tropical wetland and rice
δ
13
C

CH
4

sources and hints at significant seasonal variation in tropical wetland
δ
13
C

CH
4

signatures which may be important to capture in future global and regional models.

This article is part of a discussion meeting issue ‘Rising methane: is warming feeding warming? (part 2)’.
Permafrost thaw driven changes in hydrology and vegetation cover increase trace gas emissions and climate forcing in Stordalen Mire from 1970 to 2014
Authors: Varner Ruth K. , Crill Patrick M. , Frolking Steve , McCalley Carmody K. , Burke Sophia A. , Chanton Jeffrey P. , Holmes M. Elizabeth ,   Isogenie Project Coordinators, Saleska Scott , Palace Michael W. 
Published: December 2021

Permafrost thaw increases active layer thickness, changes landscape hydrology and influences vegetation species composition. These changes alter belowground microbial and geochemical processes, affecting production, consumption and net emission rates of climate forcing trace gases. Net carbon dioxide (CO2) and methane (CH4) fluxes determine the radiative forcing contribution from these climate-sensitive ecosystems. Permafrost peatlands may be a mosaic of dry frozen hummocks, semi-thawed or perched sphagnum dominated areas, wet permafrost-free sedge dominated sites and open water ponds. We revisited estimates of climate forcing made for 1970 and 2000 for Stordalen Mire in northern Sweden and found the trend of increasing forcing continued into 2014. The Mire continued to transition from dry permafrost to sedge and open water areas, increasing by 100% and 35%, respectively, over the 45-year period, causing the net radiative forcing of Stordalen Mire to shift from negative to positive. This trend is driven by transitioning vegetation community composition, improved estimates of annual CO2and CH4exchange and a 22% increase in the IPCC's 100-year global warming potential (GWP_100) value for CH4. These results indicate that discontinuous permafrost ecosystems, while still remaining a net overall sink of C, can become a positive feedback to climate change on decadal timescales.This article is part of a discussion meeting issue ‘Rising methane: is warming feeding warming? (part 2)’.
Isotopic signatures of methane emissions from tropical fires, agriculture and wetlands: the MOYA and ZWAMPS flights
Authors:   MOYA/ZWAMPS Team, Nisbet Euan G. , Allen Grant , Fisher Rebecca E. , France James L. , Lee James D. , Lowry David , Andrade Marcos F. , Bannan Thomas J. , Barker Patrick , Bateson Prudence , Bauguitte Stéphane J.-B. , Bower Keith N. , Broderick Tim J. , Chibesakunda Francis , Cain Michelle , Cozens Alice E. , Daly Michael C. , Ganesan Anita L. , Jones Anna E. , Lambakasa Musa , Lunt Mark F. , Mehra Archit , Moreno Isabel , Pasternak Dominika , Palmer Paul I. , Percival Carl J. , Pitt Joseph R. , Riddle Amber J. , Rigby Matthew , Shaw Jacob T. , Stell Angharad C. , Vaughan Adam R. , Warwick Nicola J. , E. Wilde Shona 
Published: December 2021

We report methane isotopologue data from aircraft and ground measurements in Africa and South America. Aircraft campaigns sampled strong methane fluxes over tropical papyrus wetlands in the Nile, Congo and Zambezi basins, herbaceous wetlands in Bolivian southern Amazonia, and over fires in African woodland, cropland and savannah grassland. Measured methaneδ13CCH4isotopic signatures were in the range −55 to −49‰ for emissions from equatorial Nile wetlands and agricultural areas, but widely −60 ± 1‰ from Upper Congo and Zambezi wetlands. Very similarδ13CCH4signatures were measured over the Amazonian wetlands of NE Bolivia (around −59‰) and the overallδ13CCH4signature from outer tropical wetlands in the southern Upper Congo and Upper Amazon drainage plotted together was −59 ± 2‰. These results were more negative than expected. For African cattle,δ13CCH4values were around −60 to −50‰. Isotopic ratios in methane emitted by tropical fires depended on the C3 : C4 ratio of the biomass fuel. In smoke from tropical C3 dry forest fires in Senegal,δ13CCH4values were around −28‰. By contrast, African C4 tropical grass fireδ13CCH4values were −16 to −12‰. Methane from urban landfills in Zambia and Zimbabwe, which have frequent waste fires, hadδ13CCH4around −37 to −36‰. These new isotopic values help improve isotopic constraints on global methane budget models because atmosphericδ13CCH4values predicted by global atmospheric models are highly sensitive to theδ13CCH4isotopic signatures applied to tropical wetland emissions. Field and aircraft campaigns also observed widespread regional smoke pollution over Africa, in both the wet and dry seasons, and large urban pollution plumes. The work highlights the need to understand tropical greenhouse gas emissions in order to meet the goals of the UNFCCC Paris Agreement, and to help reduce air pollution over wide regions of Africa.This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 2)'.
From sink to source: high inter-annual variability in the carbon budget of a Southern African wetland
Authors: Helfter Carole , Gondwe Mangaliso , Murray-Hudson Michael , Makati Anastacia , Skiba Ute 
Published: December 2021

We report on three years of continuous monitoring of carbon dioxide (CO2) and methane (CH4) emissions in two contrasting wetland areas of the Okavango Delta, Botswana: a perennial swamp and a seasonal floodplain. The hydrographic zones of the Okavango Delta possess distinct attributes (e.g. vegetation zonation, hydrology) which dictate their respective greenhouse gas (GHG) temporal emission patterns and magnitude. The perennial swamp was a net source of carbon (expressed in CO2-eq units), while the seasonal swamp was a sink in 2018. Despite differences in vegetation types and lifecycles, the net CO2uptake was comparable at the two sites studied in 2018/2020 (−894.2 ± 127.4 g m−2 yr−1at the perennial swamp, average of the 2018 and 2020 budgets, and −1024.5 ± 134.7 g m−2 yr−1at the seasonal floodplain). The annual budgets of CH4were however a factor of three larger at the permanent swamp in 2018 compared to the seasonal floodplain. Both ecosystems were sensitive to drought, which switched these sinks of atmospheric CO2into sources in 2019. This phenomenon was particularly strong at the seasonal floodplain (net annual loss of CO2of 1572.4 ± 158.1 g m−2), due to a sharp decrease in gross primary productivity. Similarly, drought caused CH4emissions at the seasonal floodplain to decrease by a factor of 4 in 2019 compared to the previous year, but emissions from the perennial swamp were unaffected. Our study demonstrates that complex and divergent processes can coexist within the same landscape, and that meteorological anomalies can significantly perturb the balance of the individual terms of the GHG budget. Seasonal floodplains are particularly sensitive to drought, which exacerbate carbon losses to the atmosphere, and it is crucial to improve our understanding of the role played by such wetlands in order to better forecast how their emissions might evolve in a changing climate. Studying such hydro-ecosystems, particularly in the data-poor tropics, and how natural stressors such as drought affect them, can also inform on the potential impacts of man-made perturbations (e.g. construction of hydro-electric dams) and how these might be mitigated. Given the contrasting effects of drought on the CO2and CH4flux terms, it is crucial to evaluate an ecosystem's complete carbon budget instead of treating these GHGs in isolation.This article is part of a discussion meeting issue ‘Rising methane: is warming feeding warming? (part 2)’.
Airborne quantification of net methane and carbon dioxide fluxes from European Arctic wetlands in Summer 2019
Authors: Barker Patrick A. , Allen Grant , Pitt Joseph R. , Bauguitte Stéphane J.-B. , Pasternak Dominika , Cliff Samuel , France James L. , Fisher Rebecca E. , Lee James D. , Bower Keith N. , Nisbet Euan G. 
Published: December 2021

Arctic wetlands and surrounding ecosystems are both a significant source of methane (CH4) and a sink of carbon dioxide (CO2) during summer months. However, precise quantification of this regional CH4source and CO2sink remains poorly characterized. A research flight using the UK Facility for Airborne Atmospheric Measurement was conducted in July 2019 over an area (approx. 78 000 km2) of mixed peatland and forest in northern Sweden and Finland. Area-averaged fluxes of CH4and carbon dioxide were calculated using an aircraft mass balance approach. Net CH4fluxes normalized to wetland area ranged between 5.93 ± 1.87 mg m−2 h−1and 4.44 ± 0.64 mg m−2 h−1(largest to smallest) over the region with a meridional gradient across three discrete areas enclosed by the flight survey. From largest to smallest, net CO2sinks ranged between −513 ± 74 mg m−2 h−1and −284 ± 89 mg m−2 h−1and result from net uptake of CO2by vegetation and soils in the biosphere. A clear gradient of decreasing bulk and area-averaged CH4flux was identified from north to south across the study region, correlated with decreasing peat bog land area from north to south identified from CORINE land cover classifications. While N2O mole fraction was measured, no discernible gradient was measured over the flight track, but a minimum flux threshold using this mass balance method was calculated. Bulk (total area) CH4fluxes determined via mass balance were compared with area-weighted upscaled chamber fluxes from the same study area and were found to agree well within measurement uncertainty. The mass balance CH4fluxes were found to be significantly higher than the CH4fluxes reported by many land-surface process models compiled as part of the Global Carbon Project. There was high variability in both flux distribution and magnitude between the individual models. This further supports previous studies that suggest that land-surface models are currently ill-equipped to accurately capture carbon fluxes inthe region.This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 2)'.
Opinion mining towards blockchain technology adoption for accessing digital library resources
Authors: Khan Asad Ullah , Zhang Zhiqiang , Taleby Ahvanooey Milad , Rafique Wajid 
Published: December 2021

PurposeBlockchain technology is a distributed and decentralized public digital ledger, which is employed to save dynamic transaction data and static records across several computers so that each record could not be modified retroactively without the collusion of the network and alteration of all subsequent blocks. Recently, it has become immensely popular in digital resource sharing in different research areas such as healthcare, smart cities, cryptocurrency and libraries. Since the current eLibrary systems are vulnerable to issues such as unauthorized access, plagiarism, etc., there is a lack of access control system that can efficiently address these issues.Design/methodology/approachThe authors designed a conceptual model for evaluating the users' intention in the use of blockchain-based digital libraries, which can facilitate the resource organization and provide additional security to interactive processes between users. To conduct our survey, the authors devised and shared two versions, English and Chinese, among 298 participants. Moreover, 7 PhD students participated in the pre-testing of the questioner design. The authors analyzed the demographic data using the Jamovi software and SmartPLS in order to generate the path modeling.FindingsThis study revealed that blockchain technology adaption in eLibraries is essential for enhancing the quality of services, infrastructure and resources for libraries. The study’s results show that optimism, informativeness, perceived usefulness, perceived ease of use, attitude and intention to use blockchain technology for accessing digital resources in libraries.Originality/valueThis study contributes to the adoption of blockchain technology in the digital library. To the best of the authors’ knowledge, this work is the first empirical attempt to provide a new perspective of developing digital libraries based on security policies. This model shows the underpinning knowledge to manage digital resources, which can facilitate the design phases and enhance the management costs in eLibraries.
Cooperator or supporter: how can cross-boundary Macau–Zhuhai metropolis promote regional tourism together?
Authors: Song Xi , Mo Ziying , Liu Matthew Tingchi , Niu Ben , Huang Li 
Published: December 2021

PurposeThis study initiated an investigation of how the Macau–Zhuhai tourism cooperated and discussed how Macau and Zhuhai could join hands to develop tourism in the region. The study demonstrated an approach for destination marketing organizations to explore online tourist-generated content and to understand tourists' perceptions of the destination image (DI).Design/methodology/approachA total of 1,291,057 reviews (535,317 for Macau and 755,740 for Zhuhai) were collected, analyzed and examined to determine how the DI s of Macau and Zhuhai changed during the period of 2015–2019 based on tourist-generated content on travel websites (TripAdvisor, Ctrip.com and Qyer.com) through a text-mining approach.FindingsThe result revealed that Macau and Zhuhai were in a hybrid of competition and collaboration on tourism DI s. First, Macau and Zhuhai competed in hotel and catering industry. Macau was appealing to international tourists and provided high-end and prestigious offerings; while Zhuhai was impressed by cost-effective accommodation and food. Second, Macau diversified industrial structure with diverse “Tourism, Leisure and Recreation” and “Culture, History and Art” more than Zhuhai did. Meanwhile, Macau should balance the different demands of international and Chinese tourists. Third, complementary potentials were found in natural resources, urbanization technology and tourism innovation and related projects.Practical implicationsThe research provides valuable insights for policymakers and industrial managers on their endeavors to develop DIs. Policymakers should be able to develop supportive mechanisms and tourism facilitators to promote industrial collaboration and mutual DIs. Managers could refer to the components in the changing DIs and identify the developmental gaps and cooperation potentials in their targeted areas.Originality/valueThe research fulfills the gap in regional tourism studies on Macau, in which the evaluation on synergetic influence and neighbor effect from Zhuhai has been underexplored. Facilitated by up-to-date data mining techniques, the study contributes to both DI and coopetition literature in tourism marketing; and this should inspire further studies on the antecedences of DI changes, resolutions to the competing interests and DIs of different stakeholders in different forms of strategic cooperation in regional tourism. The employment of DIs is an explicit demonstration of tourists' immersion and values attached to the destination, providing effective cues on the status of coopetition.
Study on oil starvation at the oil seal edge of the oil film of hydrostatic bearing with double rectangular cavity
Authors: Ni Shiqian , Zhang Yanqin , Quan Zhen 
Published: December 2021

Purpose
When the clearance oil film of hydrostatic bearing friction pair is in critical lubrication state, the phenomenon of zero flow of local lubricating oil will aggravate the oil film temperature rise, which needs to be solved.

Design/methodology/approach
In this paper, the critical lubrication parameter equation and the oil film temperature rise mathematical model are derived for the new type q1-205 double rectangular cavity hydrostatic bearing. Based on a combination of theoretical analysis, simulation and experimental verification, this paper analyzes the flow characteristics and temperature rise characteristics of the lubricating oil when the hydrostatic bearing is in a critical lubrication state under different operating conditions and finally obtains the critical lubrication state of the oil film.

Findings
This study found that the numerical simulations and the derived formulas agree with the results. When the oil film is in critical lubrication, the cross-section side flow of the oil side is almost zero. The heat cannot be taken away in time, resulting in the local temperature rise of the oil film, which causes serious heat accumulation.

Originality/value
It is concluded that the operating condition parameters corresponding to the critical lubrication state provide a theoretical basis for the selection of actual hydrostatic bearing operating conditions, which is of great scientific significance.
Artificial intelligence algorithms to predict Italian real estate market prices
Authors: Rampini Luca , Re Cecconi Fulvio 
Published: December 2021

PurposeThe assessment of the Real Estate (RE) prices depends on multiple factors that traditional evaluation methods often struggle to fully understand. Housing prices, in particular, are the foundations for a better knowledge of the Built Environment and its characteristics. Recently, Machine Learning (ML) techniques, which are a subset of Artificial Intelligence, are gaining momentum in solving complex, non-linear problems like house price forecasting. Hence, this study deployed three popular ML techniques to predict dwelling prices in two cities in Italy.Design/methodology/approachAn extensive dataset about house prices is collected through API protocol in two cities in North Italy, namely Brescia and Varese. This data is used to train and test three most popular ML models, i.e. ElasticNet, XGBoost and Artificial Neural Network, in order to predict house prices with six different features.FindingsThe models' performance was evaluated using the Mean Absolute Error (MAE) score. The results showed that the artificial neural network performed better than the others in predicting house prices, with a MAE 5% lower than the second-best model (which was the XGBoost).Research limitations/implicationsAll the models had an accuracy drop in forecasting the most expensive cases, probably due to a lack of data.Practical implicationsThe accessibility and easiness of the proposed model will allow future users to predict house prices with different datasets. Alternatively, further research may implement a different model using neural networks, knowing that they work better for this kind of task.Originality/valueTo date, this is the first comparison of the three most popular ML models that are usually employed when predicting house prices.
The joint effect of supervisor influence and investor perspective: unintended consequences on assessing accounting estimates
Authors: Dong Lei , Wang Lei , Chien Wen-Wen 
Published: December 2021

Purpose
The purpose of this paper is to examine the joint effect of supervisor influence and investor perspective on novice auditors’ assessments of accounting estimates.

Design/methodology/approach
The experiment used a 2 × 2 between-subjects design, randomly assigning proxies of novice auditors among four conditions. The authors manipulated the supervisor’s level of emphasis on evidence that suggests accounting estimate adjustment and whether auditors are prompted to take an investor perspective. Participants were asked to assess the misstatement risk of the allowance for doubtful accounts of the client company.

Findings
The authors find that auditors assign a higher (lower) risk of misstatement when their supervisor places high (low) emphasis on evidence suggesting accounting adjustment. The authors also find that contrary to the belief that taking the perspective of investors could enhance objectivity and independence, investor perspective leads to a decrease (rather than an increase) in auditors’ perceived risk of misstatement when the supervisor places low emphasis on evidence suggesting accounting adjustment.

Originality/value
This study provides early evidence on the efficacy of investor perspective and is one of the first to document an unintended consequence of asking auditors to take an investor perspective.
Impact of COVID-19 on Saudi Arabia's economy: evidence from macro-micro modelling
Authors: Alharbi Raed 
Published: December 2021

PurposeEven with the Saudi Arabian Government's discretionary measures to mitigate the spread of the coronavirus disease 2019 (COVID-19), the economic sectors were not spared from the damage. Thus, the paper aims to use a computable general equilibrium (CGE) model to evaluate the impact of COVID-19 on the Kingdom of Saudi Arabia's (KSA) economy, with a special focus on small and medium enterprises (SMEs) and production. These influence the level of poverty.Design/methodology/approachThe paper adopted the social accounting matrix (SAM) for Saudi Arabia built in 2021 by Imtithal Althumairi from Saudi Arabia's 2017 SAM. The model represents a snapshot of the economy and different flows that exist within the tasks and institutions. Two simulations (mild and severe) were conducted because of the focus on the distributional outcomes.FindingsDecrease in job creation and economic growth were significant evidence from the study's findings. Findings show that more families hit below the poverty line because the negative impacts of the pandemic have shifted the income allocation curve. Findings show that the weakest of the poor are mitigated by government social grants during the pandemic.Research limitations/implicationsThe paper is restricted to the relevant literature relating to the impact of COVID-19 on Saudi Arabia's economy and evaluated using the SAM model. Moreover, the COVID-19 is still an ongoing scenario; thus, the model should be updated as data utilised for the operationalisation are made available.Practical implicationsThe information from the suggested model can be suitable to measure the degree of the harm, and thus, the likely extent of the desirable policy feedback. Also, the model can be updated, as data are made available and formulated policies based on the updated data implemented by the policymakers.Originality/valueApart from the recovery planning of SMEs during the pandemic, the paper intends to stir up Saudi Arabia's policymakers through the macro-micro model to recovery planning and resilience of the economy with emphasis on mitigating unemployment.