Distinct Cycle Research Articles

Optimal Planning of Standalone Rural Microgrid With Effective Dispatch Strategies and Battery Technology

ABSTRACTMicrogrids are a viable substitute for traditional power systems because they may deliver cleaner, more dependable, affordable power with fewer losses. However, the microgrid's performance is impacted by the variable nature of renewable energy sources. Battery storage is a crucial component of microgrid planning since it defines the system's techno‐economic feasibility. A standalone rural microgrid is designed in the current study, employing three distinct battery types: lithium‐ion, lead acid, and zinc‐bromine flow. The suggested microgrid's techno‐economic analysis employs three distinct dispatch mechanisms, that is, cycle charging, load flow, and complete dispatch. The case study of the suggested framework is carried out in Lucknow (India). The system comprises PV/battery/wind energy system/diesel and battery. The simulation results suggest that the optimal system with the least electrification cost is 0.113 $/kWh using complete dispatch strategies and a zinc‐bromine battery. It has 206 kWh zinc‐bromine flow batteries, a 10 kW converter, a 20 kW PV, a 13‐kW diesel generator, and a Combined dispatch strategy. The system's net present cost per unit cost of energy is $40 275 and 0.113 $/kWh for the chosen region, respectively. Compared to the other two battery technologies for hybrid systems, the zinc‐bromine flow battery technology is also shown to be the most environmentally friendly. Among the three battery technologies available, zinc‐bromine flow is best used in a particular location's hybridized operation.

Life Cycle Prediction of Airport Operation Based on System Dynamics

Traditional airport development planning often overlooks an in-depth consideration of the airport operation life cycle, which frequently causes deviations from planned objectives during operation. This paper presents a framework for predicting and segmenting the airport operation life cycle by integrating the dynamic characteristics of the System Dynamics (SD) model with the static properties of Logistic modeling to examine the development trajectory of airport operations. The influencing factors in this model are selected across three levels: airport, city, and macro-environment. A system dynamics model of airport operation is constructed using causal loop diagrams and system flow diagrams. Using Guangzhou Baiyun International Airport (CAN) as a case study, the airport’s operational capacity from 2005 to 2035 is predicted through SD simulation. Subsequently, the airport operation life cycle from 2005 to 2050 is forecasted and segmented using Logistic modeling. The results indicate that, under the standard scenario, CAN’s operational capacity experiences two declines in 2016 and 2020, attributed to airport construction and emergencies. Logistic modeling identifies three distinct life cycle phases in the airport’s operation. Furthermore, by comparing various airport operation scenarios, the analysis reveals that fluctuations in the city economy significantly impact the airport’s operational system without altering its overall development trajectory. In contrast, the occurrence of emergencies can substantially modify the airport operation life cycle.

Multivariate Evaluation of Flash Drought Across the United States

AbstractThis study uses the flash drought intensity index (FDII) to develop a multivariate flash drought climatology for the contiguous U.S. using data from 2001 to 2021. The FDII method uses the rate of intensification (FD‐INT) and subsequent drought severity (DRO‐SEV) to determine when a flash drought occurred and the strength of the event. Overall, the results showed that flash drought occurrence and severity varied with season and region and were sensitive to the drought indicator used to compute the FDII. Precipitation‐based indicators identified more flash droughts across the western U.S. whereas soil moisture (SM) and evapotranspiration indicators identified more flash droughts across the central and eastern U.S. When assessed over the entire U.S., the most flash droughts were found when using an evaporative demand indicator. Though FD‐INT was larger than DRO‐SEV across the U.S. for most indicators, regional patterns were also evident in their relative importance. For example, a distinct east‐west gradient was present in the SM and evapotranspiration FD‐INT, with relatively large values in the central and eastern U.S. A combined data set synthesizing information from multiple indicators showed that the strongest flash droughts from a multivariate perspective were located in the central and southeastern U.S. A seasonal analysis revealed a distinct seasonal cycle in flash drought onset across the western and central U.S. Together, the results illustrate the need to use a multivariate framework to identify and characterize the occurrence and severity of flash droughts.

Identification of Sulfur Dioxide (SO2) Hotspots of Gujarat state using Sentinel 5P-TROPOMI

Sulphur dioxide (SO2) is a widely recognized pollutant with far-reaching consequences for human health, climate, and the environment. This study aims to identify SO2 hotspots within the state of Gujarat located in the western part of India using the Sentinel 5P TROPOMI satellite data. Based on the analysis of the satellite data from January 2019 to 2023, 16 hotspot regions were identified in Gujarat with significantly high concentration of SO2. Majority of these hotspots were located in industrial areas and petroleum refineries, including Mundra port, Ahmedabad, Vadodara, Surat, and the Alang shipbreaking yard. Notably, some scattered hotspots were found near Eco-sensitive zones like Purna and Narayan Sarovar. The observed SO2 concentrations in these hotspots vary between ~ 10 to ~ 1000 µmol/m2, with an average concentration of ~ 300 µmol/m2. It is also observed that SO2 concentration is significantly elevated during winter and pre-summer months, with a marked reduction during the monsoon season. The average monthly SO2 concentrations exhibit a distinct seasonal cycle, with the lowest levels during the monsoon and the highest during winter. Furthermore, impact of COVID induced lockdown is also perceived across the state.

A 45-year updating wind and wave hindcast over the Oman Sea and the Arabian Sea

This study focuses on developing a comprehensive and reliable wind and wave hindcast for the Oman Sea and Arabian Sea, spanning a significant 45-year period (1979–2024). The objective is to capture the intricate wind and wave climate of the region, characterized by distinct monsoon cycles and occasional tropical cyclones. The availability of extensive wave data over four decades would be an irreplaceable tool for researchers and engineers, enabling improved accuracy in extreme value analysis, sediment transport studies, and wave-induced current simulations. Despite limited field observations, all available measured data within the region were collected, analyzed for configuration of the models and utilized for model calibration and validation. The hindcast data was generated using the Weather Research and Forecasting (WRF) model for winds and WAVEWATCH III (WW3) model for waves, and evaluated against observational and measured wind and wave parameters. A comprehensive statistical analysis of the hindcast model's performance reveals adequate agreement with measured data, as evidenced by root mean square errors (RMSEs) of 1.23 m/s for wind speeds and 0.37 m for significant wave heights in average. These results underscore the model's reliability for research and engineering applications, particularly in the Arabian Sea, with a focus on the northern coastlines of the Oman Sea. The specific model configuration employed in this study holds significant potential for future investigations in the northern Indian Ocean, offering a valuable tool for understanding and predicting climatical conditions in this region.

Measurement report: Urban ammonia and amines in Houston, Texas

Abstract. Ammonia and amines play critical roles in secondary aerosol formation, especially in urban environments. However, fast measurements of ammonia and amines in the atmosphere are very scarce. We measured ammonia and amines with a chemical ionization mass spectrometer (CIMS) at the urban center in Houston, Texas, the fourth most populated urban site in the United States, during October 2022. Ammonia concentrations were on average four parts per billion by volume (ppbv), while the concentration of an individual amine ranged from several parts per trillion by volume (pptv) to hundreds of pptv. These reduced nitrogen compounds were more abundant during weekdays than on weekends and correlated with measured CO concentrations, implying they were mostly emitted from pollutant sources. Both ammonia and amines showed a distinct diurnal cycle, with higher concentrations in the warmer afternoon, indicating dominant gas-to-particle conversion processes taking place with the changing ambient temperatures. Studies have shown that dimethylamine is critical for new particle formation (NPF) in the polluted boundary layer, but currently there are no amine emission inventories in global climate models (as opposed to ammonia). Our observations made in the very polluted area of Houston, as well as a less polluted site (Kent, Ohio) from our previous study (You et al., 2014), indicate there is a consistent ratio of dimethylamine over ammonia at these two sites. Thus, our observations can provide a relatively constrained proxy of dimethylamine using 0.1 % ammonia concentrations at polluted sites in the United States to model NPF processes.

Impact of piezoelectric driving waveform on performance characteristics of vibrating mesh atomizer (VMA)

Vibrating mesh atomizer (VMA) is a specific type of ultrasonic atomizer known for its low power consumption and production of uniformly fine droplets. While previous research has provided a basic understanding of VMA operation, it has primarily focused on driving the piezoelectric actuator with continuous and symmetrical waveforms, such as sine and square waveforms. This study aims to experimentally investigate the impact of different driving waveforms on the ultrasonic atomization process and the associated performance characteristics. Specifically, the effects of pulse waveforms (Gauss and Lorentz pulse) were analyzed with high rates of energy deposition and asymmetrical hybrid waveforms (trapezia and absolute sine), featuring distinct negative cycles, by comparing them with conventional symmetrical waveforms (sine and square). Pulse waveforms suppress the growing stage but provide a high flux of input energy, facilitating the detachment of liquid into fine droplets, resulting in uniformly distributed droplets with VMDs of 5.84 μm and 4.71 μm for Gauss and Lorentz waveforms, respectively. Conversely, shorter negative cycles in asymmetrical hybrid waveforms reduce liquid suction into the micronozzle, leading to higher energy flux during subsequent positive cycles that promote the growing stage, producing larger droplets with VMDs of 10.82 μm and 11.86 μm for trapezia and absolute (abs) sine waveforms, respectively. Additionally, high-speed imaging reveals irregular pulsating behaviors in the atomization process when using pulse waveforms, suggesting a reciprocating-pump-like operation mechanism in VMA atomization. These new insights contribute to an improved understanding of the atomization mechanism in VMAs.

Novel hydrazide-hydrazone containing 1,2,4-triazole as potent inhibitors of antiapoptotic protein Bcl-xL: Synthesis, biological evaluation, and docking studies.

This study describes the synthesis and characterization of a series of novel hydrazide-hydrazone derivatives containing a 1,2,4-triazole ring. The compounds were characterized using various spectroscopic techniques, such as FT-IR, 1H-NMR, 13C-NMR, HRMS, and elemental analysis. The antiproliferative activity of the synthesized compounds was evaluated against a panel of human cancer cell lines (HCT-116, HepG-2, KLN205, LTPA, U138, and SW620) and healthy cell lines (HSkMC and iPSCs). Among the compounds tested, compounds 4, 5p, 5r, and 5s showed the highest effectiveness in inhibiting the growth of cancer cells with Bcl-xL inhibitory concentration (IC50) values. These compounds further demonstrated selective cytotoxicity against the Bcl-xL-dependent lymphoma cell line (DBs). Molecular docking studies were also performed to investigate the potential binding interactions of compounds 4, 5p, 5r, and 5s with the active site of Bcl-xL (PDB ID: 7LH7, 1.4 Å). Mechanistic studies revealed that compounds 4, 5r, and 5s induced apoptosis predominantly through the intrinsic mitochondrial pathway, while compound 5p exhibited a distinct cell cycle arrest profile, impacting both the S and G2/M phases. Western blot analysis suggested that these compounds may downregulate cyclin expression, thereby blocking its association with Bcl-xL. Overall, these results demonstrate the potential of these novel hydrazide-hydrazone derivatives as anticancer agents with activity comparable or superior to doxorubicin and 5-fluorouracil.

On the k-Spanning Cyclability of 4-Valent Cayley Graphs on Abelian Groups

A graph X is k -spanning cyclable if for any subset S of k distinct vertices there is a 2-factor of X consisting of k cycles such that each vertex in S belongs to a distinct cycle. In this paper, we examine the k -spanning cyclability of 4-valent Cayley graphs on Abelian groups.

Prosumer Neo-Tribes: An Ethnography of Recreational Cycling Communities

Abstract In postmodern community studies, a neo-tribal theoretical framework has been proposed to elucidate recreational and touristic communities, positing that neo-tribes coalesce around shared consumer experiences. This study diverges by examining the productive functions of recreational and tourist communities through the lens of prosumerism. The study investigates two distinct recreational cycling tribes in Türkiye using ethnographic methods and participatory observations. The findings highlight that these cycling tribes play active roles in organizing events, developing visitor experiences and destinations, and generating both economic and social benefits. This study introduces the concept of prosumer tribes within the leisure and tourism literature, supported by empirical evidence. It offers implications for policymakers and businesses seeking to understand and harness the prosumer dynamics within recreational cycling communities.

Vehicle emission models alone are not sufficient to understand full impact of change in traffic signal timings

Few studies have considered the real-world impact of changes in traffic signal timings on air pollution and pedestrian exposure with most only drawing their conclusion from vehicle emission models alone. Here, we consider two distinct cycle timings at a junction in London, UK, model the impact using a traffic microsimulation and a NOx emissions model, and compare these results with NOx and other air pollution measurements collected during a two-week field study at the junction.Our models predict that extending the cycle time leads to a 23% decrease in NOx emissions within a 15 m radius of the junction itself. When the wind direction was such that our sensors were downwind of the junction a 21% decrease in traffic and background-adjusted NOx concentrations were seen, suggesting that the intervention was successful. However, when the sensors were upwind of the junction, we observed an increase of 23% in adjusted NOx concentrations. Similar patterns were found for the other pollutants NO2, lung deposited surface area, black carbon and CO2 we measured. This indicates that meteorology was by far the greatest determinant of roadside concentrations during our two-week study period.Looking at pedestrian exposure for pedestrians waiting to cross the road, we found that their NOx exposure increased by 46% as waiting times to cross the road increased and that potential small reductions in air pollution were offset by increases in waiting times on the main road.The study demonstrates the need to go beyond assessing the impact of hyper-local traffic interventions on vehicle emissions. Real-world trials over extended periods are required to evaluate the impact of meteorology and changes to air pollution concentrations and pedestrian exposures.

Carbosulfonylation of Alkynes: A Direct Conversion of sp-C to sp3-C through Visible Light-Mediated 3-Component Reaction.

A 3-component metal-free carbosulfonylation of alkynes is reported using readily available alkyl carboxylic acids and arylsulfinates under visible light irradiation. This photochemical approach gives direct conversion of sp-C to sp3-C yielding highly functionalized alkyl sulfones. It employs feedstock chemicals as starting materials and shows a broad substrate scope and moderate diastereoselectivity. The method's utility is highlighted in the synthesis of sedum alkaloids. A single photocatalyst is proposed to be active in two distinct photocatalytic cycles operating in tandem.

Impacts of Local Circulations on Ozone Pollution in the New York Metropolitan Area: Evidence From Three Summers of Observations

AbstractElevated surface ozone levels are often detected in the New York metropolitan area during summertime. Moreover, surface ozone in this region exhibits sharp spatial gradients and distinctive diurnal cycles under the influence of complex boundary layer circulations induced by the intricate coastal geometry. This study examines how surface ozone is impacted by local circulations spatially and temporally under different temperature scenarios (all summer days, hot summer days, and extreme heat days) with the help of cluster‐based meteorological conditions during the summertime of 2017–2019. The most polluted days are found to be highly associated with hot sea breeze days with weak background flow. When sea breeze development in the New York Bight is delayed and its penetration north is intercepted by the dominant westerlies during hot summer days, daily maximum 8‐hr average ozone (DMA8) in some ozone hot spots of New York City (NYC) and the south shore of Connecticut (CT) typically drops 9–10 ppb under comparable temperature levels. The average regional decrease of DMA8 for NYC and coastal CT is 6.7 and 8.3 ppb, respectively. Furthermore, we conclude that a change in early morning meridional wind direction is the most critical meteorological characteristic in controlling sea breeze onset type and helping modulate ozone exceedances in the region during extreme hot days when ozone exceedances are expected to be very common. The conclusion is further demonstrated with two case studies during the Long Island Sound Tropospheric Ozone Study 2018 field campaign.

Effect of RapidShockTM Implementation on Perishock Pause in Out-of-Hospital Cardiac Arrest

Objectives Shorter pauses in cardiopulmonary resuscitation (CPR) are associated with better health outcomes after out-of-hospital cardiac arrest (OHCA). Our primary objective was to examine the effect of a RapidShockTM defibrillator software upgrade compared with standard defibrillator software on the length of perishock pause during care for OHCA among adults. Secondary objectives were to assess the effects of RapidShockTM on other CPR pauses. Methods We conducted a retrospective cohort study between September 1, 2015 and September 30, 2020. “Standard” cardiac defibrillator software in manual interpretation mode was used for CPR delivered on or before November 30, 2018, while “RapidShockTM” software (ZOLL® Medical Corporation) was used after this date. For each study group, we calculated the perishock, perianalysis, and total CPR pause; each CPR cycle was considered an independent event. We then calculated the median and interquartile range (IQR) for observed pauses with the “Standard” and “RapidShockTM” software. Percent change in median perishock pause (shockable rhythms), perianalysis pause (non-shockable rhythms), and total CPR pause were compared between CPR administered with each software using the Mann–Whitney test. Results There were 733 and 782 distinct CPR cycles administered using “Standard” and “RapidShockTM” software, respectively. A 31.8% reduction in median perishock pause was observed with “RapidShockTM” software compared with the “Standard” software (22.0 s (IQR 18.0 − 27.0 s) vs. 15.0 s (IQR 13.0 − 19.0 s); p < 0.01). The decrease in median perishock pause was driven by a reduction in the preshock phase (18 s vs. 10 s; 44.4% decrease in median pause; p < 0.01). No differences were observed in median perianalysis pause between the two groups. When combining shockable and non-shockable rhythms, we observed a reduction of 23.5% in median CPR pause (17.0 s (IQR 11.0 − 24.0 s) vs. 13s (IQR 10.0 − 17.0 s); p < 0.01). Conclusions Overall, we observed that the use of “RapidShockTM” defibrillator software was associated with shorter CPR pauses compared with the “Standard” software. Additional studies are required to examine whether further reductions in CPR pauses may be achieved and to investigate associations between shorter CPR pauses and health outcomes.

Enhanced visualization of nuclear staining and cell cycle analysis for the human commensal Malassezia

Malassezia is a lipophilic commensal yeast that resides mainly on the mammalian skin and is also found to associate with the internal organs. Dysbiosis of Malassezia is related to several diseases and often escapes detection as it is difficult to culture and maintain. Malassezia cell wall differs from other budding yeasts like S. cerevisiae due to the difference in the lipid content and is difficult to transform. In this study, we present a methodology to stain Malassezia's nucleus and perform cell cycle studies. However, staining presents a challenge due to its exceptionally thick cell wall with high lipid content, hindering conventional methods. Our novel methodology addresses this challenge and enables the staining of the Malassezia nucleus with a low background. This would allow researchers to visualize the overall nuclear health specifically nuclear morphology and analyze DNA content, crucial for cell cycle progression. By employing DNA-specific dyes like DAPI or Hoechst, we can observe the nuclear structure, and using PI we can differentiate cells in distinct cell cycle phases using techniques like flow cytometry. This novel staining methodology unlocks the door for in-depth cell cycle analysis in Malassezia which has challenged us through ages being refractory to genetic manipulations, paving the way for a deeper understanding of this commensal fungus and its potential role in human health.

Electricity and hydrogen fuel generation based on wind, solar energies and alkaline fuel cell: A hybrid IWGAN–AVOA approach

Addressing the pressing need for sustainable energy solutions, this paper proposes a novel hybrid energy system integrating wind, alkaline fuel cells and solar energies. This paper introduces a pioneering hybrid energy system designed to produce electricity and hydrogen fuel through the integration of wind, solar energies, and an alkaline fuel cell. The proposed approach, coined as IWGAN–AVOA technique, synergizes the improved Wasserstein generative adversarial network (IWGAN) and the African vultures optimization algorithm (AVOA). The primary aim is to delineate a distinctive energy cycle reliant on renewable sources, featuring a Stirling engine, electrolyzer, alkaline fuel cell, wind turbine, and solar photovoltaic system, with the objective of generating hydrogen fuel and energy. The AVOA enhances fuel cell capabilities, simulates optimal system component sizes, and rectifies erroneous configurations based on geographical specifics. By validating the efficacy of IWGAN, the study achieves optimal configurations for device capacities and enhances power flow efficiency. Comparative analyses reveals that the IWGAN–AVOA approach surpasses existing techniques, like particle swarm optimization (PSO), wild horse optimizer (WHO), and heap based optimizer (HBO), with a remarkable efficiency rate of 98%, outperforming current methods. The last figure illustrates the effectiveness comparison, showcasing efficiencies of 62%, 79%, and 85% for HBO, PSO, and WHO, respectively, against the superior 98% efficiency achieved by the IWGAN–AVOA approach, affirming its superiority in energy system optimization.

Spatial–temporal variations of sediment transport rate and driving factors in Shule River Basin, northwest China

The sediment content and transport rate of rivers are crucial indicators reflecting soil erosion, water quality, and water resource management in a region. Studying changes in river sediment transport rates within a basin is essential for evaluating water quality, restoring water ecosystems, and implementing soil and water conservation measures. This study focused on the Shule River Basin and utilized various methods such as moving average, cumulative anomaly, Mann–Kendall mutation test, Mann–Kendall (M–K) trend test, Sen’s slope estimation, Correlation analysis, wavelet analysis, R/S analysis, ARCGIS10.7 interpolation, non-uniformity coefficient, and concentration to analyze data from hydrologic stations at Changmapu (CMP), Panjiazhuang (PJZ), and Dangchengwan (DCW). The research examined the temporal and spatial characteristics of sediment transport rates and identified key driving factors. Findings revealed significant increases in annual sediment transport rates at CMP and PJZ by 12.227 and 4.318 kg/s (10a)−1, respectively, while DCW experienced a decrease of 0.677 kg/s (10a)−1. The sediment transport rate of the three stations had a sudden change around 1994. The average annual sediment transport rates displayed distinct cycles, with CMP, PJZ, and DCW showing cycles of 51a, 53a, and 29a respectively. Additionally, while CMP and PJZ exhibited a continuous upward trend in sediment transport rates, DCW showed a consistent decline. The annual average sediment transport rates of CMP, PJZ, and DCW were 1305.43 kg/s, 810.06 kg/s, and 247.80 kg/s, respectively. These research findings contribute to enhancing the comprehension of sediment dynamics in the arid region of northwest China and offer a theoretical basis for the restoration and management of ecological environments in similar areas in the future.

Metabolomic profiling of pheochromocytomas in dogs: Catecholamine phenotype and tricarboxylic acid cycle metabolites.

In humans with pheochromocytomas (PCCs), targeted metabolomics is used to determine the catecholamine phenotype or to uncover underlying pathogenic variants in tricarboxylic acid (TCA) cycle genes such as succinate dehydrogenase subunits (SDHx). To analyze catecholamine contents and TCA cycle metabolites of PCCs and normal adrenals (NAs). Ten healthy dogs, 21 dogs with PCC. Prospective observational study. Dogs diagnosed with PCC based on histopathological and immunohistochemical confirmation were included. Tissue catecholamine contents and TCA metabolites in PCCs and NAs were measured by liquid chromatography with mass spectrometry or electrochemical detection. Compared to NAs, PCCs had significantly higher tissue proportion of norepinephrine (88% [median: range, 38%-98%] vs 14% [11%-26%]; P < .001), and significantly lower tissue proportion of epinephrine (12% [1%-62%] vs 86% [74%-89%]; P < .001). Pheochromocytomas exhibited significantly lower fumarate (0.4-fold; P < .001), and malate (0.5-fold; P = .008) contents than NAs. Citrate was significantly higher in PCCs than in NAs (1.6-fold; P = .015). One dog in the PCC group had an aberrant succinate : fumarate ratio that was 25-fold higher than in the other PCCs, suggesting an SDHx mutation. This study reveals a distinct catecholamine content and TCA cycle metabolite profile in PCCs. Metabolite profiling might be used to uncover underlying pathogenic variants in TCA cycle genes in dogs.

Iron cycling and isotopic fractionation in a ferruginous, seasonally ice-covered lake

Ferruginous conditions, defined by anoxia and abundant dissolved ferrous iron (Fe2+aq), dominated the Precambrian oceans but are essentially non-existent in a modern, oxygenated world. Ferruginous meromictic lakes represent natural laboratories to ground truth our understanding of the stable Fe isotope proxy, which has been used extensively in interpreting the origins of Fe-rich sedimentary rocks like iron formations (IFs) and the interactions of early life with high-Fe2+aq conditions. Here we report comprehensive geochemical and Fe isotopic analyses of samples collected in May and August 2022, and March 2023, from Deming Lake, Minnesota, a ferruginous meromictic lake that undergoes surface freezing in winter and never becomes euxinic. Through chemical and Fe isotopic analyses of different putative Fe sources to Deming Lake; including eolian input trapped in winter ice cover, nearby bogs, and regional groundwaters sampled at surface springs; we find that a groundwater source provides the best chemical and Fe isotopic match for Deming Lake and can support Fe2+aq-rich waters at depth that maintain a permanent chemocline at ∼12 m. The ice-free Deming Lake water column can be split into three layers dominated by distinct Fe cycling regimes. Layer (I) extends from the lake surface to the base of the oxycline at ∼6 m, and its Fe cycling is dominated by isotopically light Fe uptake into biomass, likely from stabilized dissolved Fe3+, with variable eolian lithogenic influences. Layer (II) extends between the oxycline and the chemocline at ∼12 m and is dominated by partial Fe2+aq oxidation on approach to the oxycline, with the formation of variably isotopically heavy Fe3+-bearing particles. Layer (III) underlies the chemocline and is defined by Fe2+ phosphate (vivianite) and carbonate saturation and precipitation under anoxic, Fe2+aq-rich conditions with little Fe isotopic fractionation. The ice-covered winter water column features more homogenous Fe chemistry above the chemocline, which we attribute to seasonal homogenization of Layers (I) and (II), with suppressed ferric particle formation. Authigenic Fe minerals with non-crustal (light) Fe isotopic compositions only appreciably accumulate in sediments in Deming Lake underlying the chemocline. All sediments deposited above 12 m appear crustal in their Fe isotopic, Mn/Fe, and Fe/Al ratios, likely revealing efficient reductive dissolution of Fe3+-bearing lake precipitates and remineralization of Fe-bearing biomass. We find limited fractionation of Fe isotopes in the ice-covered water column and suggest this provides evidence that substantial delivery of oxidants is required to generate highly fractionated Fe isotopic compositions in Sturtian Snowball era IFs. By comparing Fe isotopic and Mn/Fe fractionation trends in the different Deming Lake layers, we also suggest that correlations between these two parameters in giant early Paleoproterozoic IFs requires the simultaneous deposition of multiple authigenic phases on the ancient seafloor. Finally, high-precision triple Fe isotopic analyses of dissolved Fe impacted by extensive oxidation near the Deming Lake oxycline reveal that the slope of the mass fractionation law for natural, O2-mediated Fe2+aq oxidation is identical to those previously defined for both UV photo-oxidation, and for an array of highly fractionated Paleoproterozoic IFs.

Implementation of a population mental health and wellness text-message service: a mixed-methods study

BackgroundDespite the growing adoption of digital health tools as a means to support mental health, many individuals remain unaware of the variety of mental health resources available to them through this format. To address this knowledge gap, this study advanced the design, development, and implementation of a text-based service called SaskWell to raise awareness of evidence based mental health resources and create more immediate connections to these tools. The two primary objectives of the study were to assess and evaluate the adoption of SaskWell by focusing on user acceptance, satisfaction, and perceived benefit, and to identify factors which contributed to user engagement with the SaskWell text-based service. Both quantitative and qualitative data contributed to the final study results.ResultsThis study utilized a co-designed text-messaging service to provide residents of Saskatchewan an important connection to digital mental health and wellness resources during the height of the COVID-19 pandemic. Using the RE-AIM framework as an implementation guide, four distinct cycles of SaskWell were delivered with modifications to the service in each subsequent cycle based on user engagement, feedback, and the direction of a community advisory group. Quantitative data was collected through user engagement text message response data, along with enrollment and exit surveys, while semi-structured interviews served as the primary means of qualitative data collection. In addition to the quantitative user data, these user interviews resulted in themes exploring motivation to sign-up for the service, perceptions of texting as a mechanism to deliver mental health resources, the impact of SaskWell on mental health and well-being, and beliefs on the future potential of text-based mental health supports.ConclusionsBoth the user engagement survey and the qualitative data supported the worth of ongoing efforts to refine and extend the use of text messaging as a means to engage citizens around the awareness and use of digital mental health and wellness resources. As the pandemic has receded into the background in many peoples’ daily lives, for healthcare providers, and others who continue to be impacted more heavily by the persistent challenges of this global event, this type of service may continue to be timely.