Net Loss Research Articles

Multidecadal mangrove forest change in Macajalar Bay, Northern Mindanao, Philippines (1950-2020) using remote sensing and geographic information systems.

The mangrove forest in Macajalar Bay is regarded as an important coastal ecosystem since it provides numerous ecosystem services. Despite their importance, the clearing of mangroves has been rampant and has reached critical rates. Addressing this problem and further advancing its conservation require accurate mangrove mapping. However, current spatial information related to mangroves is sparse and insufficient to understand the historical change dynamics. In this study, the synergy of 1950 vegetation maps and Landsat images was explored to provide multidecadal monitoring of mangrove forest change dynamics in Macajalar Bay, Philippines. Vegetation maps containing the 1950 mangrove extent and Landsat images were used as input data to monitor the rates of loss over 70years. In 2020, the mangrove forest cover was estimated to be 201.73ha, equivalent to only 61.99% of the 325.43ha that was estimated in 1950. Between 1950 and 2020, net mangrove loss in Macajalar Bay totaled 324.29ha. The highest clearing rates occurred between 1950 and 1990 when it recorded a total of 258.51ha, averaging 6.46ha/year. The original mangrove forest that existed in 1950 only represents 8.56% of the 2020 extent, suggesting that much of the old-growth mangrove had been cleared before 2000 and the existing mangrove forest is mainly composed of secondary mangrove forest stands. Across Macajalar Bay, intensified clearing that happened between 1950 and 1990 has been driven by large-scale aquaculture developments. Mangrove gains on the other hand were evident and have increased the total extent by 79.84ha since 2000 as a result of several afforestation programs. However, approximately half of these gains that were observed since 2010 exhibited low canopy cover. As of writing, approximately 85% of the 2020 mangrove forest stands fall outside the 1950 original mangrove extent. Examining the viability of the original mangrove forest for mangrove reforestation together with promoting site-species matching, and biophysical assessment are necessary undertakings to advance current mangrove conservation initiatives in Macajalar Bay.

Mortality from the 1944–1945 famine in Java, Indonesia

AbstractThis article examines the human toll of the 1944–1945 famine in Java, Indonesia's main island. It estimates birth and death rates for the Indonesian population in Java during 1941–1951. Using the net population loss method, the article approximates a net loss of 3.3 million people during the 1942–1945 Japanese occupation period. This includes 1.8 million excess deaths; 0.7 million during 1944 and 1.1 million during 1945. The remainder are 1.4 million missing births in 1944 and 1945, associated with the malnutrition of women of childbearing ages and physical separation of wives from husbands recruited by Japanese authorities for forced labour.

Financing ecosystem restoration

The global community has outlined ambitious ecosystem restoration targets. Yet implementation is slow, and a lack of funding is a key barrier to upscaling restoration activities. Most restoration projects are funded by public institutions and recent high-level initiatives have emphasised the need to scale private finance in restoration. Private finance can be channelled into restoration through various financial mechanisms but is held back by a lack of return-making investment opportunities. Various institutions have now been created to commodify previously non-market ecosystem services and make them investable, most prominently voluntary carbon markets and biodiversity compliance market-like mechanisms, such as biodiversity-offsetting systems targeting the achievement of 'no net loss' of biodiversity for a given regulated sector. However, attracting private finance into restoration comes with risks, as private finance objectives in restoration often are misaligned with wider social and ecological objectives. Private finance mechanisms to date have tended to underinvest in monitoring and impact evaluation mechanisms and to favour investments in cost-effective nature-based solutions such as plantation monocultures over naturally regenerated ecosystems. Many technological and institutional solutions have been proposed, but these cannot mitigate all risks. Therefore, scaling of ecosystem restoration through market-like mechanisms requires substantial fundamental investments in governance and civil society oversight to ensure that ecological integrity and social equity is safeguarded. Here, we outline the high-level policy landscape driving restoration finance and explore the roles and potential of both public and private investment in restoration. We explain how some common mechanisms for drawing private investment into restoration work in practice. Then, we discuss some of the shortcomings of past private finance initiatives for ecosystem restoration and highlight essential lessons for how to safeguard the ecological and social outcomes of private investments in ecosystem restoration.

Coordination of PSS and Multiple FACTS-POD to Improve Stability and Operation Economy of Wind-thermal-bundled Power System

Aims and Background: Focusing on the low-frequency oscillation and system power loss problem in wind-thermal-bundled (WTB) transmission systems and the interaction problem due to different controllers, this study aimed to improve the low-frequency oscillation characteristics of WTB transmission system while ensuring the economy of operation and suppressing the adverse interaction between controllers. Methods: For this purpose, a coordination and optimization strategy for a power system stabilizer (PSS), static synchronous series compensator with additional power oscillation damping controller (SSSC-POD), and static synchronous compensator with additional power oscillation damping controller (STATCOM-POD) is proposed based on multi-objective salp swarm algorithm (MSSA). The controller regulation characteristics are taken into account in the coordination method. Results: Several designed scenarios, including changing the transmission power of the tie line and increasing wind power output, are considered in the IEEE 4-machine 2-area to test the proposed method. The power flow analysis, characteristic root analysis, and time-domain simulation are used to analyze the simulation results. Conclusion: Simulation results demonstrate that the proposed approach can effectively suppress the low-frequency oscillation of the WTB system while reducing its net loss. The application in engineering issues for MSSA is supplemented.

Microbial response to long-term fertilization of paddy soils: Apparent and real priming effects

Fertilization is crucial for increasing crop productivity and it alters soil microbial biomass and activities. These alterations exert implications for soil carbon (C) stocks, primarily through the priming effect (PE). Here, we investigated the mechanisms underlying PE and their impact on soil C stocks in paddy soils subjected to long-term (31 years) fertilization. Soils from four depths within the upper 40 cm layer, subjected to four fertilization types (no fertilizer, mineral fertilizer, mineral + straw, mineral + chicken manure), were incubated for 60 days with or without 13C-labeled glucose. Following substrate addition, an increase in isotopically unlabeled CO2 efflux may stem from accelerated microbial turnover (apparent PE) or modified SOM mineralization (real PE). By analyzing microbial biomass (MBC), CO2 and dissolved organic C (DOC) dynamics, we explored the partitioning of C from glucose into three pools. Following glucose addition (day 2), the soil organic matter (SOM)-derived MBC decreased by 4.7 % at 0–10 cm in unfertilized and by 6.3 % in mineral-fertilized soils. SOM-derived MBC also decreased in soils fertilized with straw- and chicken manure at 0–20 and 0–30 cm. Hence, the apparent PE closely correlated with fertilization types. At day 2, the SOM-derived DOC increased with the increase in extractable Fe2+ content, indicating high contribution of the released mineral-bound organic C in the DOC pool. Microbial decomposition of SOM-derived DOC and loss of unlabeled C through apparent PE increased the release of unlabeled CO2, resulting in a positive but low PE. After 60 days of incubation, the addition of glucose to the subsoils (30–40 cm) caused a net loss of C (positive PE) of 6.6–19 mg kg−1. In contrast, negative PEs were observed in the topsoil, indicating a decrease in microbial activity and C turnover. These findings suggested that fertilization regimes, whether involving long-term extra C input or not, can alter microbial biomass and turnover rates. Moreover, the C turnover mechanisms in paddy soils are complex, including apparent PE, release of mineral-bound organic C, and negative PE. Collectively, these processes can consequently change soil C stocks.

Temporal Dynamics of Canopy Properties and Carbon and Water Fluxes in a Temperate Evergreen Angiosperm Forest

The forest–atmosphere exchange of carbon and water is regulated by meteorological conditions as well as canopy properties such as leaf area index (LAI, m2 m−2), photosynthetic capacity (PC μmol m−2 s−1), or surface conductance in optimal conditions (Gs, opt, mmol m−2 s−1), which can vary seasonally and inter-annually. This variability is well understood for deciduous species but is poorly characterized in evergreen forests. Here, we quantify the seasonal dynamics of a temperate evergreen eucalypt forest with estimates of LAI, litterfall, carbon and water fluxes, and meteorological conditions from measurements and model simulations. We merged MODIS Enhanced Vegetation Index (EVI) values with site-based LAI measurements to establish a 17-year sequence of monthly LAI. We ran the Community Atmosphere Biosphere Land Exchange model (CABLE-POP (version r5046)) with constant and varying LAI for our site to quantify the influence of seasonal canopy dynamics on carbon and water fluxes. We observed that the peak of LAI occurred in late summer–early autumn, with a higher and earlier peak occurring in years when summer rainfall was greater. Seasonality in litterfall and allocation of net primary productivity (FNPP) to leaf growth (af, 0–1) drove this pattern, suggesting a complete renewal of the canopy before the timing of peak LAI. Litterfall peaked in spring, followed by a high af in summer, at the end of which LAI peaked, and PC and Gs,opt reached their maximum values in autumn, resulting from a combination of high LAI and efficient mature leaves. These canopy dynamics helped explain observations of maximum gross ecosystem production (FGEP) in spring and autumn and net ecosystem carbon loss in summer at our site. Inter-annual variability in LAI was positively correlated with Net Ecosystem Production (FNEP). It would be valuable to apply a similar approach to other temperate evergreen forests to identify broad patterns of seasonality in leaf growth and turnover. Because incorporating dynamic LAI was insufficient to fully capture the dynamics of FGEP, observations of seasonal variation in photosynthetic capacity, such as from solar-induced fluorescence, should be incorporated in land surface models to improve ecosystem flux estimates in evergreen forests.

Acute Effects of Testosterone on Whole-Body Protein Metabolism in Hypogonadal and Eugonadal Conditions: A Randomized, Placebo-Controlled, Crossover Study.

Chronic testosterone (T) substitution and short-term T administration positively affect protein metabolism, however, data on acute effects in humans are sparse. This study aimed to investigate T's acute effects on whole-body protein metabolism in hypogonadal and eugonadal conditions. We designed a randomized, double-blind, placebo-controlled, crossover study, including twelve healthy young males. Whole-body protein metabolism was evaluated during 1) eugonadism, and after medically-induced hypogonadism, with application of a gel on each trial day containing either 2) placebo, 3) T 50 mg, or 4) T 150 mg; under basal (5h basal period) and insulin-stimulated conditions (3h clamp). The main outcome measure was change in net protein balance. The net protein loss was 62% larger in the placebo-treated hypogonadal state compared with the eugonadal state during the basal period (-5.5 ±3.5 µmol/kg/h versus -3.4 ± 1.2 µmol/kg/h, p=0.038), but not during the clamp (p=0.06). Also, hypogonadism resulted in a 25% increase in whole-body urea flux (p=0.006). However, T did not result in any significant changes in protein breakdown, synthesis, or net balance during either the basal period or clamp (all p > 0.05). Protein breakdown was reduced during clamp compared to the basal period regardless of gonadal status or T exposure (all p≤0.001). In conclusion, the application of transdermal T did not counteract the negative effects of hypogonadism with no effects on protein metabolism within five hours of administration. Insulin (during clamp) mitigated the effects of hypogonadism. This study is the first to investigate acute protein-metabolic effects of T in hypogonadal men.

Net Loss: An econometric method to measure the impact of Internet shutdowns

Net Loss: An econometric method to measure the impact of Internet shutdowns

Liraglutide 3.0 mg once daily for the treatment of overweight and obesity in patients hospitalised at a forensic psychiatric department: A 26-week open-label feasibility study.

Overweight and obesity constitute a major concern among patients treated at forensic psychiatric departments. The present clinical feasibility study aimed at investigating the extent to which glucagon-like peptide 1 receptor agonist (GLP-1RA) treatment with once-daily liraglutide 3.0 mg could be a feasible pharmacological treatment of these conditions in patients with schizophrenia spectrum disorders hospitalised in forensic psychiatry. The 26-week, open-label feasibility study included participants aged 18-65 years diagnosed with a severe mental illness and hospitalised at a forensic psychiatric department. At the time of inclusion, all participants fulfilled the indication for using liraglutide as a treatment for overweight and obesity. Participants' baseline examinations were followed by a 26-week treatment period with liraglutide injection once daily according to a fixed uptitration schedule of liraglutide, with a target dose of 3.0 mg. Each participant attended seven visits to evaluate the efficacy and adverse events. The primary endpoint was the number of "completers", with adherence defined as >80% injections obtained in the period, weeks 12-26. Determining whether liraglutide is a feasible treatment was pre-defined to a minimum of 75% completers. Twenty-four participants were included in the study. Sex, male = 19 (79.2%). Mean age: 42.3 [25th and 75th percentiles: 39.1; 48.4] years; body mass index (BMI): 35.7 [31.7; 37.5] kg/m2; glycated haemoglobin (HbA1c): 37 [35; 39] mmol/mol. Eleven out of 24 participants (46%) completed the study. For the completers, the median net body weight loss after 26 weeks of participation was -11.4 kg [-15.4; -5.9]. The net difference in HbA1C and BMI was -2.0 mmol/mol [-4; -1] and -3.6 kg/m2 [-4.7; -1.8], respectively. The weight change and reduction in HbA1c and BMI were all statistically significant from baseline. The study did not confirm our hypothesis that liraglutide is a feasible treatment for a minimum of 75% of the patients initiating treatment with liraglutide while hospitalised in a forensic psychiatric department. The high dropout rate may be due to the non-naturalistic setting of the clinical trial. For the proportion of patients compliant with the medication, liraglutide 3.0 mg was an efficient treatment for overweight.

Power sector decarbonisation in developing and coal-producing countries: A case study of Indonesia

Global efforts to transition away from coal within a decade encounter significant challenges, particularly in developing and coal-producing countries, e.g. Indonesia. Most current studies do not discuss the impact of coal phase-out on the upstream sector, which is important for coal-producing countries. This study aims to analyse Indonesia's power sector decarbonisation impact on the power and fossil upstream sectors. This analysis used VEDA-TIMES energy system optimisation using three scenarios: least-cost system (BAU), decarbonisation without coal phase-out (PA 1.5), and decarbonisation with coal phase-out (PA 1.5 PO). In all cases, decarbonisation will reduce the amount of coal used in energy systems. However, in a technology-agnostic transition, coal still constitutes 16% of total capacity in 2060. By this time, the coal-fired power generating assets have also transitioned to high efficiency, low emissions (HELE) technologies. CCS plays an important role in Indonesia's decarbonisation. A key implication of the coal phase-out scenario is the stranding of $9 bn worth of existing assets and an increased role for renewable energy and imported natural gas in 2035–2050, posing a notable threat to gas security within the industrial sector. In addition, the potential loss due to untapped coal reserves is estimated at $63 bn, while the cumulative net loss in the coal upstream sector amounts to $799 bn (0.26% of Indonesia's GDP and 3.7% of the coal-producing GDRP). Nevertheless, the total investment and electricity production costs exhibit negligible differences in the rapid VRE expansion, but it will reduce total investment by 24% in the low VRE buildrate.

The maintenance of long-term weight loss after semaglutide withdrawal in obese women with PCOS treated with metformin: a 2-year observational study.

Withdrawal of semaglutide is frequently followed by weight regain due to compensatory biological changes that prevent the maintenance of long-term weight loss. There are some studies implying that metformin might attenuate weight regain. The weight trajectory after discontinuation of short-term semaglutide treatment in obese women with PCOS who continued metformin treatment has not yet been evaluated. We explored changes in body weight, cardiometabolic and endocrine parameters in obese women with PCOS who continued treatment with metformin 2 years after discontinuation of short-term intervention with semaglutide. 25 women with PCOS and obesity, aged 33.7 ± 5.3 years (mean ± SD), were treated with once-weekly subcutaneous semaglutide 1.0 mg as an adjunct to metformin 2000 mg/day and lifestyle intervention for 16 weeks. At week 16, semaglutide was discontinued. Treatment with metformin 2000 mg/day and promotion of lifestyle intervention were continued during the 2-year follow-up period. Weight change, cardiometabolic, and endocrine parameters were assessed 2 years after semaglutide discontinuation. During semaglutide treatment phase, weight decreased from 101 (90-106.8) kg to 92 (83.3-100.8) kg. Two years after semaglutide withdrawal, weight was 95 (77-104) kg. The net weight loss 2 years after discontinuation of semaglutide remained significant when compared to baseline (p=0.003). At the end of the study, 21 out of 25 subjects had lower body weight compared to baseline. Improvements in cardiometabolic parameters including decrease in total and LDL cholesterol, fasting glucose, and glucose after OGTT that had been seen during semaglutide-treatment phase reverted towards baseline two years after semaglutide cessation. Free testosterone levels significantly decreased during semaglutide treatment from 6.16 (4.07-9.71) to 4.12 (2.98-6.93) nmol/l, (p= 0.012) and did not significantly deteriorate after semaglutide discontinuation. Two years after semaglutide withdrawal, women with PCOS who continued with metformin regained about one-third of the semaglutide-induced weight loss. At the end of the follow up, 84% of women had a lower body weight than at baseline.

Exploitation of Agricultural Groundwater for Urban Areas

Ground water is the most accessed source of water for domestic, industrial, and agricultural purposes. Significant social and economic repercussions could result from a declining water table and the depletion of groundwater resources that are economically accessible. Domestic water supply is given top emphasis in both National and State water policy formulation. Recently, there has been a rise in water transfers to satisfy the needs of the industrial and residential sectors.  With the success of the state water supply, many are heralding groundwater transfer as the quickest, least expensive and most environmentally benign solution to large cities water supply and reliability problem. In order to satisfy urban domestic and industrial water demand, the majority of water transfers concentrate on buying water from farmers who are prepared to sell it to them. The present study was undertaken mainly to study the impacts of economic and environmental gains and losses related to the groundwater transfer in Tiruppur district. Without doubts groundwater transfer from agriculture to industrial uses would benefit individual sellers, buyers and the Nation as whole. The adverse direct economic impact in groundwater selling or water transferring areas to total revenue in agriculture was Rs. 54.32 lakhs per every crop season. Scarcity of water resulted in shifting of irrigated agriculture to rainfed agriculture and labour intensive to labour less intensive crops. The total employment lost per hectare of land was 198.33 man-days. Secondly, another adverse indirect economic and environmental impact of water transfer is discharge of large quantum of industrial effluent water. Moreover, there is indirect economic and environmental impact on effluent receiving areas due to highly polluted industrial effluent discharge into open lands and river/streams could cause a Rs. 22,296 net personal income loss for every hectare of land. At larger perspective impacts of groundwater transfer could be considered insignificant.

A profile of urban agricultural growers, organizations, their needs, and challenges in the Northeastern United States.

Urban agriculture is increasingly valued as a strategy for improving quality of life in cities, but urban growers face challenges and often lack coordinated support from governments and the agricultural industry. We surveyed urban growers through an online survey, primarily in the Northeastern United States, to develop a profile of growers and associated organizations, assess the current state of urban agriculture, and determine how universities could help meet their needs. A total of 394 respondents completed the survey and most urban growers were white (non-Hispanic) and younger than 45 years old. Women and men were in almost equal proportion. Urban growers were well-educated, but most did not receive a degree in agriculture. Urban agriculture in our study area was dominated by relatively small non-profit organizations and home and community gardens were the most common types of organizations. Urban agricultural organizations want to improve environmental sustainability and socio-cultural conditions through food access and security, regardless of their tax status. Urban growers face diverse barriers and challenges and the most ubiquitous barriers and challenges reported by respondents were related to availability of land and long-term access in urban areas. Many respondents received low revenue or were operating at a net loss even though they reported diverse income streams. Respondents need a wide range of training, including in traditional agricultural topics as well as financial management and business trainings. Universities can play a key role in promoting urban agriculture by offering training and research. Workforce development is a large priority among universities, so urban growers should regularly be consulted, and the results shared with career and workforce development professionals and researchers in urban areas to identify training and research that meets the needs of stakeholders.

Overtime: Long-Term Betting Trajectories Among Highly-Involved and Less-Involved Online Sports Bettors.

Online sports gambling involvement is discontinuous in nature, with small groups of highly involved gamblers exhibiting betting behavior that is distinctly greater than other gamblers. There is some question about whether these groups, defined by exceedingly high levels of play, also have equivalently high rates of gambling problems, and whether they maintain these play levels over time. The current study builds on past work by examining the long-term trajectories of play and voluntary self-exclusion patterns across two years among a cohort of 32,262 highly-involved and less-involved online sports gamblers. We also examine the relative importance of betting behavior change as a risk factor for gambling problems by testing whether high involvement as compared to escalation of involvement is a better predictor of future self-exclusion. Measures included betting activities, transactional activities, and self-exclusion activities on a European online betting platform between February 2015 and January 2017. Results showed that bettors who were most highly involved in the first 8 months of the study in terms of number of bets and net loss were more likely to continue gambling on the platform in months 9-24 than others. Bettors who were most highly involved in the first 8 months of the study in terms of net loss and amount wagered were more likely to use self-exclusion than others, and more likely to have multiple self-exclusions. Escalations in frequency of play and average bet size within the first 8 months emerged as significant predictors of self-exclusion, even when controlling for high involvement.

Net Farm Income Impacts Net Worth Growth

The beginning of the year is busy for businesses in finalizing records and filing annual income taxes. Farm and ranch operations are no exception. Beyond the net income or loss showing on the farm’s Schedule F, analyzing the true picture of the operation’s net farm income, and earned net worth change for the year is important. Preparing an income statement using accrual adjustments will tell us more about the operation’s profitability and performance beyond what income tax statements provide. The income statement tells the story of revenue, expenses, and depreciation between the beginning of year balance sheet and the end of the year balance sheet. Hence, an important use of an income statement is to relate true profitability from the beginning of the period to the end as we observe changes in the balance sheets.

Futile cycles: Emerging utility from apparent futility.

Futile cycles are biological phenomena where two opposing biochemical reactions run simultaneously, resulting in a net energy loss without appreciable productivity. Such a state was presumed to be a biological aberration and thus deemed an energy-wasting "futile" cycle. However, multiple pieces of evidence suggest that biological utilities emerge from futile cycles. A few established functions of futile cycles are to control metabolic sensitivity, modulate energy homeostasis, and drive adaptive thermogenesis. Yet, the physiological regulation, implication, and pathological relevance of most futile cycles remain poorly studied. In this review, we highlight the abundance and versatility of futile cycles and propose a classification scheme. We further discuss the energetic implications of various futile cycles and their impact on basal metabolic rate, their bona fide and tentative pathophysiological implications, and putative drug interactions.

Achieving green mobility: Multi-objective optimization for sustainable electric vehicle charging

This study optimizes and evaluates a Photovoltaic-Wind-Battery/Electric Vehicle Charging Station (PVWB/EVCS) system using four Multi-Objective Optimization (MOO) techniques: MOPSO, NSGAII, NSGAIII, and MOEA/D. The main goals are to minimize the Total Net Present Cost (TNPC) and Loss of Power Supply Probability (LPSP) of the system, which are crucial for sustainable electric vehicle charging. The study analyzes the economic, operational, and sustainability aspects of the optimized system and compares it with HOMER software. The results show that NSGA-II is the best MOO technique for this problem, as it has the best performance and robustness. The Discounted Cash Flow analysis confirms the economic feasibility and sustainability of the optimized system over its lifetime. The technical analysis demonstrates the system's ability to use renewable energy from solar and wind sources, along with efficient energy storage and distribution. The study also conducts a sensitivity analysis to investigate the effects of changes in load, irradiance, wind speed, and component costs on the system performance. The findings reveal the system's resilience and adaptability under different scenarios, thus enhancing its suitability for renewable energy generation and electric vehicle charging. The study showed that the optimized PVWB/EVCS system is a promising solution for reducing reliance on non-renewable sources and promoting a more eco-friendly sustainable future.

Big Cities, Big Impacts? A spatial analysis of 3,335 ecological offsets in France since 2012

This paper assesses the French policy of mitigation hierarchy, with the aim of no net loss of biodiversity, by studying the geographical aspects of the application of the concept of ecological offsets in equivalence between losses and gains using spatialized data. We seek to know whether the dynamics of urban and interurban development (notably built-up and transport infrastructures) lead to a spatially integrated implementation of biodiversity offsets taking into account local characteristics and areas under pressure from land artificialization. Our main finding reveals that the majority of ecological offsets are generated by projects related to transport infrastructures (38%) and urban planning and construction projects (23%). However, if there are fewer, the ecological offsets of projects such as waste storage or energy development are mostly located in natural preserved areas, revealing a potential risk of non additionnality of offset measures and a risk that the private sector (through ecological offsets) will gradually replace the state in the protection of biodiversity. Our analysis also points out that despite the diversity of projects, habitats and protected species across France, there is a typical spatial layout profile of ecological offsets, pleading for a “one size fits all” offsetting in the French policy context of tenuous regulators’ availability in time and competence level due to weakness of refresh training and downsizing of public services in the environment. This last result argues for a stronger control from environmental agencies between two tremendously tricky concepts of offsetting, the equivalence valuation methods and the adjustments coefficients (time delay and ecological risk), to drive ecological offsetting future decisions at local but above all regional- and national-level planning documents.

Losses of native mineral-associated organic nitrogen through microbial mineralization and gaseous emissions induced by ammonium and nitrate addition

Atmospheric nitrogen (N) deposition has a significant impact on terrestrial N cycling. However, it has not been well understood how external inorganic N addition affects the dynamics of soil organic N (SON) that supports long-term plant productivity and carbon (C) sequestration. Here, we added six levels of ammonium (NH4+-N) or nitrate (NO3−-N) to a temperate grassland soil to reveal the mechanisms of SON responses to inorganic N addition. Results showed that the SON content decreased by 7% ± 2%–15% ± 1%, which corresponded with the increase in the abundance of functional gene related to SON mineralization (i.e., chiA) by both NH4+-N and NO3−-N. The inorganic N addition stimulated gaseous losses from the native soil N, leading to at least 6% ± 2%–12% ± 1% of the initial SON lost at different N addition levels (i.e., N-priming). However, the responses of nitrification- and denitrification-related functional genes to NH4+-N and NO3−-N treatments varied remarkably. The positive responses of nitrification- and denitrification-related functional genes (i.e., hao, nirS, and narG) to NO3−-N addition contributed to gaseous N losses. The negative responses of some denitrification-related functional genes (i.e., nirK, narG, and napA) to NH4+-N addition resulted in less gaseous N losses by NH4+-N compared with that by NO3−-N addition. Additionally, the release of H+ by NH4+-N addition may liberate organic matter from associated minerals, showing a decrease in mineral-associated organic matter (MAOM) but an increase in extractable Fe. These findings provide direct evidence that the addition of inorganic N results in a net native SON loss through microbe-mediated mineralization and gaseous emissions. The study also emphasizes the different mechanisms of reduced and oxidized N additions in affecting SON mineralization and gaseous N losses.

Effects of channel structure at inlet region on temperature distribution of proton exchange membrane fuel cells

Enhancing the temperature distribution uniformity in membrane electrodes is crucial for improving the durability and performance stability of proton exchange membrane fuel cells. In this study, we discovered an entrance region in the cathode membrane electrode of proton exchange membrane fuel cells characterized by a rapid rise in temperature. This inlet region shows a notably higher temperature variation rate compared to other regions. This phenomenon is attributed to the temperature difference between the constant temperature fluid supplied by the channel inlet and the heat generation in the cathode catalyst layer. Thus, the impact of channel structure at the entrance region on the temperature distribution of the cathode catalyst layer is investigated, based on a three-dimensional, non-isothermal, two-phase model. Results show that boosting heat transfer in the inlet region is more effective for reducing the average temperature than in other regions. We proposed five kinds of step arrangement schemes and discovered that the step arrangement in the entrance region of the cathode flow channel can increase the temperature uniformity of the cathode catalyst layer by 9.71% without net power loss. Furthermore, this study examines the impact of length, height of entrance steps, and outlet channel height on heat transfer and identifies the optimum value. When severe water flooding occurs, the gas purge coupled with the step-fronted scheme is essential for improving temperature uniformity.