Average Cl Research Articles

The in-situ generation of ClO• by single- and dual-atom catalysis of chloride ions to degrade sulfonamide antibiotics: A DFT study

Single- (SACs) and dual-atom catalysts (DACs) are recognized as promising electrochemical materials. However, their application potential in the water treatment with the presence of chloride ions (the most common water matrice) still needs to be investigated. Thus, the first-principles calculation was used to investigate the electrocatalytic activation of Cl− and micropollutant degradation mechanisms by four kinds of metal-embedded nitrogen-doped carbon materials (M-N-C). The results show that the average Cl− adsorption energies (Eads) in different configurations follow the order of M2N6-a < M2N8 < MN4 < M2N6-b. The average Eads of SACs and DACs doped with different metal atoms follow the order of Fe < Co < Ni and Fe2 < FeNi < FeCo < CoNi ≈ Co2 < Ni2, respectively. The chlorine evolution reactions (CER) on the FeN4 and Fe2N6-a in neutral water were revealed as Cl− → *Cl → HClO* → free HClO, and HClO will rapidly generate ClO• to degrade target pollutants. The generated ClO• exhibits high reactivity towards sulfanilamide antibiotics (SAs) with the reaction rate constants of 1.78 × 108–6.86 × 109 M−1 s−1, indicating the high feasibility of ClO• in SAs purification from wastewater. This study provides mechanistic insights into the electrocatalytic generation of ClO• and its application in removing contaminants of emerging concern in M-N-C-supported electrochemical advanced oxidation processes.

(S)-(+)-1-(4-Bromophenyl)-N-[(4-methoxyphenyl)methylidene]ethylamine and bis{(S)-(+)-1-(4-bromophenyl)-N-[(4-methoxyphenyl)methylidene]ethylamine-κN}dichloridopalladium(II)

The (S)-(+)-1-(4-bromophenyl)-N-[(4-methoxyphenyl)methylidene]ethylamine ligand, C16H16BrNO, (I), was synthesized through the reaction of 4-methoxyanisaldehyde with (S)-(−)-1-(4-bromophenyl)ethylamine. It crystallizes in the orthorhombic space group P212121 belonging to the Sohncke group, featuring a single molecule in the asymmetric unit. The refinement converged successfully, achieving an R factor of 0.0508. The PdII complex bis{(S)-(+)-1-(4-bromophenyl)-N-[(4-methoxyphenyl)methylidene]ethylamine-κN}dichloridopalladium(II), [PdCl2(C16H16BrNO)2], (II), crystallizes in the monoclinic space group P21 belonging to the Sohncke group, with two molecules in the asymmetric unit. The central atom is tetracoordinated by two N atoms and two Cl atoms, resulting in a square-planar configuration. The imine moieties exhibit a trans configuration around the PdII centre, with average Cl—Pd—N angles of approximately 89.95 and 90°. The average distances within the palladium complex for the two molecules are ∼2.031 Å for Pd—N and ∼2.309 Å for Pd—Cl.

Geochemical characteristics of shale gas hydraulic fracturing flowback/produced water in Zheng’an block, northern Guizhou Province, China

Guizhou Province of China is rich in shale gas resources. In recent years, important progress has been made in the exploration and development of shale gas in the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation in Zheng'an block in northern Guizhou, adjacent to Sichuan Basin. Due to the complex geological conditions and fragile ecological environment in the shale gas distribution area, serious environmental pollution risks may exist in shale gas exploitation. Therefore, this paper conducted element, hydrogen and oxygen isotope analyses for shale gas fracturing flowback/produced water of Well AY7-4 in Zheng'an block. The results showed that the contents of K, Na, Ca, Mg and NH4+ in the flowback/produced water of Well AY7-4 were very high, with an average of 118 mg/L, 7616 mg/L, 266 mg/L, 47 mg/L and 76 mg/L, respectively. The content of Na, Ca and Mg is similar to that of shale gas flowback/produced water in Weiyuan, but lower than that in Changning and Fuling. NH4+ content was similar to that in Changning, but much higher than that in Weiyuan. The average Cl content was 11605 mg/L, which was similar to that in Weiyuan, but lower than that in Changning and Fuling. The average Br content is 48 mg/L, slightly lower than that of Weiyuan, and about half of that of Changning and Fuling. Correspondingly, the Br/Cl value of Well AY7-4 is the lowest, reflecting its relatively low Br content. The average content of Li, B and Sr is 17 mg/L, 10 mg/L and 45 mg/L, respectively, which is similar to that of the Weiyuan, Changning and Fuling shale gas fields. The distribution model of Li and Sr is similar to that of Cl, Br and Na, but the B content and B/Cl value of Well AY7-4 are the lowest. The linear relationship between Br and Cl contents and between δD and δ18O of flowback/produced water of Well AY7-4, freshwater used for hydraulic fracturing and hydraulic fracturing injected fluid indicates that flowback/produced water of Well AY7-4 is mainly the mixed product between low salinity injected fracturing fluid and high salinity brine retained in shale formation. The hydrogen and oxygen isotopic compositions gradually become heavier over time, indicating that the proportion of high salt end formation brine in flowback/produced water is increasing. The contents of Cl, Br, Na and NH4+ in the flowback/produced water of Well AY7-4 are far higher than the allowable discharge value, which is a potential environmental pollution risk and cannot be discharged directly.

Airfoil Lift Coefficient Optimization Using Genetic Algorithm and IGP Parameterization: Volume 1

The objective of this study is to develop a genetic algorithm that uses the IGP parameterization to increase the lift coefficient (CL) of three airfoils to be used on wings of unmanned aerial vehicles (UAVs). The geometry of three baseline airfoils was modified by developing a genetic algorithm that operates with the IGP parameterization and performs the aerodynamic analysis using XFOIL in the MATLAB environment. Subsequently, a numerical model was made for each baseline and optimized airfoil using a commercial computational fluid dynamics (CFD) code to analyze the behavior of the lift coefficient. An increase in the average CL was obtained for the Eppler 68, MH 70, and Wortmann FX 60-126 airfoils for angles of attack ranging from 0 to 10, obtaining increments of 17.243%, 14.967%, and 10.708%, respectively. Additionally, an average 5.027% uncertainty was obtained in lift coefficient calculations between XFOIL and CFD. The utility of the IGP method and genetic algorithms for parameterizing and optimizing airfoils was demonstrated. In addition, airfoils could be tailored for a specific UAV depending on the mission profile. Volume 2 of this study will include experimental data from wind tunnel.

Nanoscale X-ray Imaging of Composition and Ferroelastic Domains in Heterostructured Perovskite Nanowires: Implications for Optoelectronic Devices.

Metal halide perovskites (MHPs) have garnered significant interest as promising candidates for nanoscale optoelectronic applications due to their excellent optical properties. Axially heterostructured CsPbBr3-CsPb(Br(1-x)Clx)3 nanowires can be produced by localized anion exchange of pregrown CsPbBr3 nanowires. However, characterizing such heterostructures with sufficient strain and real space resolution is challenging. Here, we use nanofocused scanning X-ray diffraction (XRD) and X-ray fluorescence (XRF) with a 60 nm beam to investigate a heterostructured MHP nanowire as well as a reference CsPbBr3 nanowire. The nano-XRD approach gives spatially resolved maps of composition, lattice spacing, and lattice tilt. Both the reference and exchanged nanowire show signs of diverse types of ferroelastic domains, as revealed by the tilt maps. The chlorinated segment shows an average Cl composition of x = 66 and x = 70% as measured by XRD and XRF, respectively. The XRD measurements give a much more consistent result than the XRF ones. These findings are consistent with photoluminescence measurements, showing x = 73%. The nominally unexchanged segment also has a small concentration of Cl, as observed with all three methods, which we attribute to diffusion after processing. These results highlight the need to prevent such unwanted processes in order to fabricate optoelectronic devices based on MHP heterostructures.

Efficacy of urban road salt reduction strategies on public supply well quality

Long-term road salt application has increased chloride (Cl−) concentrations in public drinking water wells in many cold climate communities. A range of Best Management Practices (BMPs) have been adopted to mitigate the impact of road deicing compounds on groundwater quality. Chronic increases in chloride levels have been observed in several municipal well fields within the southern Ontario Regional Municipality of Waterloo (RMOW). In response, the RMOW and City of Kitchener implemented a plan to reduce salt application on roads by 25% within the local capture zones of one of the impacted well fields, the Greenbrook Well Field. Here the influence of salt reduction BMPs on subsurface water quality are examined by documenting changes in pore water Cl− concentrations and stored salt mass in vadose zone core samples collected at sites near the well field both before and after the implementation of the BMPs. The data indicate that ~6 years after salt reduction measures were initiated, average pore water Cl− concentration and average cumulative stored chloride mass in the vadose zone had decreased by approximately 60% and 40%, respectively. Groundwater samples collected from shallow monitoring wells installed at each field site showed similar post-BMP reductions in shallow groundwater Cl− concentration (~35%). Long-term (1973–2022) trends in raw water Cl− concentration data from the deeper public drinking water supply wells clearly demonstrate a slow, time-lagged response of the municipal supply wells to the salt reduction BMPs. The combined results suggest that controlled reductions in road salt applications within vulnerable, capture zone regions of public supply wells can reduce the impact of road salt deicing practices on municipal groundwater supplies over time.

Respiratory mechanics and gas exchange in an ovine model of congenital heart disease with increased pulmonary blood flow and pressure.

In a model of congenital heart disease (CHD), we evaluated if chronically increased pulmonary blood flow and pressure were associated with altered respiratory mechanics and gas exchange. Respiratory mechanics and gas exchange were evaluated in 6 shunt, 7 SHAM, and 7 control age-matched lambs. Lambs were anesthetized and mechanically ventilated for 15min with tidal volume of 10mL/kg, positive end-expiratory pressure of 5 cmH2O, and inspired oxygen fraction of 0.21. Respiratory system, lung and chest wall compliances (Crs, CL and Ccw, respectively) and resistances (Rrs, RL and Rcw, respectively), and the profile of the elastic pressure-volume curve (%E2) were evaluated. Arterial blood gases and volumetric capnography variables were collected. Comparisons between groups were performed by one-way ANOVA followed by Tukey-Kramer test for normally distributed data and with Kruskal-Wallis test followed by Steel-Dwass test for non-normally distributed data. Average Crs and CL in shunt lambs were 30% and 58% lower than in control, and 56% and 68% lower than in SHAM lambs, respectively. Ccw was 52% and 47% higher and Rcw was 53% and 40% lower in shunt lambs compared to controls and SHAMs, respectively. No difference in %E2 was identified between groups. No difference in respiratory mechanics was observed between control and SHAM lambs. In shunt lambs, Rcw, Crs and CL were decreased and Ccw was increased when compared to control and SHAM lambs. Pulmonary gas exchange did not seem to be impaired in shunt lambs when compared to controls and SHAMs.

Chloride and total phosphorus budgets for Lake Nipissing, headwater of Lake Huron, Ontario, Canada

Anthropogenic sources of total phosphorus (TP) and chloride (Cl−) to lakes and rivers have been issues of concern for many decades in the Great Lakes Basin with northern Boreal Shield headwater tributaries less well studied. In the Sturgeon River – Lake Nipissing – French River basin, a headwater basin of Georgian Bay, Lake Huron, water quality monitoring of major inflows to Lake Nipissing, the third largest inland lake located entirely within Ontario, is only available from the mid-1960s to the 1990s. During the period of 2015–2018, we conducted monthly water quality surveys of major and minor inflows for two water years and have generated the first chloride (Cl−) and total phosphorus (TP) elemental budgets for the lake. Review of available long-term concentration data indicate decreasing TP concentrations by decade in major inflows, but select inflows continue to exhibit concentrations above provincial objectives, including inflows from agricultural areas that are no longer part of provincial monitoring programs. Some inflows also show high average Cl− concentrations with potential influences (e.g., road salt, agricultural activities) to stream water quality throughout the year. Water and elemental budgets indicate that while specific runoff (l/s/km2) is quite similar across contributing catchments, yields of Cl− and TP (kg/ha/yr) are disproportionately higher in catchments with urban and agricultural activities. While uncertainties in the water balance and elemental yields remain, this first effort to quantify annual elemental budgets of Lake Nipissing highlights the need to develop community-based, spatially distributed water quality surveying for long-term ecosystem monitoring and future planning.

Cl isotope fractionation in magmatic and hydrothermal eudialyte, sodalite and tugtupite (Ilímaussaq intrusion, South Greenland)

We determined the Cl stable isotope composition of Cl-rich minerals (eudialyte, sodalite and tugtupite) from evolved peralkaline rocks of the Ilímaussaq complex (South Greenland) to determine the effects of orthomagmatic and hydrothermal processes on Cl isotope variations and to estimate the Cl isotopic composition of the lithospheric mantle source for the complex.The total variation of δ37Cl values is between +0.1 and + 0.4‰ for sodalites (N = 16), 0 and + 0.3‰ for tugtupites (N = 6) and + 0.2 and + 1.7‰ for eudialytes (N = 31). This data set allowed for estimating Cl isotope fractionation between minerals, melts and fluids in a well-defined natural system. The Cl isotope fractionation between magmatic sodalite and melt is slightly negative (about −0.05‰), decreasing to about −0.1‰ during hydrothermal conditions; Cl isotope fractionation between tugtupite and fluid (about −0.2‰) is slightly larger. Magmatic eudialyte has δ37Cl values that are approximately 0.35‰ higher than magmatic sodalite, indicating Cl isotope fractionation between eudialyte and melt of about +0.3‰.The Cl isotopic composition of the melt was estimated to a δ37Cl of about +0.3‰, which may be representative for the lithospheric mantle below South Greenland. This value is within the range of δ37Cl values of various mantle reservoirs (varying between −3‰ and + 3‰) including a recently suggested value of +0.9‰ derived from Mexican mantle-derived deep geothermal waters, and the generally accepted average mantle value of −0.2‰. The data indicate that large Cl isotope heterogeneities exist within the mantle that question the validity of using a general average Cl isotope ratio when Cl isotope mantle values are discussed, and that it is important to better understand the global variability of Cl isotopes in the mantle and Cl isotope fractionation between the fluid and crystalline phases.Cl isotopes in sodalite and tugtupite samples are compared to previously published Br isotope values. The range in Cl isotope values is less than the range of Br isotope values, and different sample groups are better constraint with Br isotopes. Br isotope fractionation is larger due to competition of Br with Cl which better fits at mineral site locations in the crystals. This results in better isotope separation between different sample groups using Br isotopes. Due to low Br concentrations in most samples, it is only rarely possible to measure Br isotope compositions so that generally it is not possible to apply this comparison.

Insights into tropical cloud chemistry in Réunion (Indian Ocean): results from the BIO-MAÏDO campaign

Abstract. We present here the results obtained during an intensive field campaign conducted in the framework of the French “BIO-MAÏDO” (Bio-physico-chemistry of tropical clouds at Maïdo (Réunion Island): processes and impacts on secondary organic aerosols' formation) project. This study integrates an exhaustive chemical and microphysical characterization of cloud water obtained in March–April 2019 in Réunion (Indian Ocean). Fourteen cloud samples have been collected along the slope of this mountainous island. Comprehensive chemical characterization of these samples is performed, including inorganic ions, metals, oxidants, and organic matter (organic acids, sugars, amino acids, carbonyls, and low-solubility volatile organic compounds, VOCs). Cloud water presents high molecular complexity with elevated water-soluble organic matter content partly modulated by microphysical cloud properties. As expected, our findings show the presence of compounds of marine origin in cloud water samples (e.g. chloride, sodium) demonstrating ocean–cloud exchanges. Indeed, Na+ and Cl− dominate the inorganic composition contributing to 30 % and 27 %, respectively, to the average total ion content. The strong correlations between these species (r2 = 0.87, p value: &lt; 0.0001) suggest similar air mass origins. However, the average molar Cl-/Na+ ratio (0.85) is lower than the sea-salt one, reflecting a chloride depletion possibly associated with strong acids such as HNO3 and H2SO4. Additionally, the non-sea-salt fraction of sulfate varies between 38 % and 91 %, indicating the presence of other sources. Also, the presence of amino acids and for the first time in cloud waters of sugars clearly indicates that biological activities contribute to the cloud water chemical composition. A significant variability between events is observed in the dissolved organic content (25.5 ± 18.4 mg C L−1), with levels reaching up to 62 mg C L−1. This variability was not similar for all the measured compounds, suggesting the presence of dissimilar emission sources or production mechanisms. For that, a statistical analysis is performed based on back-trajectory calculations using the CAT (Computing Atmospheric Trajectory Tool) model associated with the land cover registry. These investigations reveal that air mass origins and microphysical variables do not fully explain the variability observed in cloud chemical composition, highlighting the complexity of emission sources, multiphasic transfer, and chemical processing in clouds. Even though a minor contribution of VOCs (oxygenated and low-solubility VOCs) to the total dissolved organic carbon (DOC) (0.62 % and 0.06 %, respectively) has been observed, significant levels of biogenic VOC (20 to 180 nmol L−1) were detected in the aqueous phase, indicating the cloud-terrestrial vegetation exchange. Cloud scavenging of VOCs is assessed by measurements obtained in both the gas and aqueous phases and deduced experimental gas-/aqueous-phase partitioning was compared with Henry's law equilibrium to evaluate potential supersaturation or unsaturation conditions. The evaluation reveals the supersaturation of low-solubility VOCs from both natural and anthropogenic sources. Our results depict even higher supersaturation of terpenoids, evidencing a deviation from thermodynamically expected partitioning in the aqueous-phase chemistry in this highly impacted tropical area.

Assessing landcover and water uses effects on water quality in a rapidly developing semi-urban coastal area of Bangladesh

We have studied the urbanization effect on water resources of a developing semi-urban area on the southeast side of Chattogram (Chittagong) city, enduring industrialization and subsequent urbanization. The landcover comprising water bodies, vegetation, and agricultural lands were 9.36%, 40.55%, and ∼37%, respectively. Domestic water demand was estimated by interviewing households, while water samples were collected using the grab sampling method from rivers, canals, ponds, and groundwater for laboratory analysis. Daily average water consumption increases with growing family size and income. 52.14 million liters per day (MLD) water is needed for households in the study area, with a per capita demand of 123.80 L per day. The daily maximum water demand range of households was 78.20 MLD – 104.27 MLD, with the peak hourly demand being 5.87 MLD. However, available aquifer recharge is estimated as low as 11 million m3 per year. Except for some points, the average pH, TDS, and Cl− values were acceptable, though EC, SS, and COD values were exceeding the water quality standards with a small amount of HCO3− and no CO3− values in the water samples, making the water of the study area less compatible for domestic purposes. The primary causes were waste disposals, saltwater intrusion, and a few instances of industrial discharge. The settlement landcover directly influences water quality parameters pH, TDS, and conductivity in compositional analysis. We believe that expanding the build-up area to the vegetated area will eventually induce water quality degradation, mainly saline water intrusion.

Mass-Balance Modeling of Metal Loading Rates in the Great Lakes

Major elements and nutrients are key water quality monitoring targets in the Great Lakes, but large-scale and long-term data for (trace) metals remains comparatively scarce. Consequently, the sources and processes controlling metal loading rates and potential accumulation in the lakes are not as well constrained. Here, we present a comprehensive assessment of select metal loads in the Great Lakes basin, aggregating tributary and connecting channel loads as well as estimates for atmospheric input and sedimentation. In total, 26,845 hydrometric and water quality datapoints from major environmental surveillance programs were compiled into mass-balance calculations and dynamic simulations for 1980–2020. Conservative element (Na, Cl) loads were used to calibrate the black-box approach, and mass-balance for these elements could be achieved at ≥90% and long-term trends accurately reproduced. In contrast, biogeochemically reactive (trace) metals Cu, Ni, Zn and Pb displayed highly variable source-sink behavior across the Great Lakes. Our results show that i) atmospheric inputs, tributary loads, and sedimentation all affect the concentrations and temporal trends of the studied metals but differently in the upper versus lower lakes, ii) smaller tributaries can be disproportionately important to lake-wide metal budgets, and iii) current loading rates may yield increasing lake-wide average Cl concentrations (e.g., up to 2.3 mg/L in Lake Superior) but decreasing metal concentrations (e.g., down to <0.25 μg/L Cu in Lake Ontario) by 2100. This work provides important quantitative baselines for metal loads in the Great Lakes and may help optimize surveillance and management strategies for the preservation of Great Lakes water quality.

B-PO02-126 LATE-IODINE ENHANCEMENT COMPUTED TOMOGRAPHY AS A MARKER FOR SCAR LOCALIZATION FOR VENTRICULAR TACHYCARDIA ABLATION IN CARDIAC SARCOIDOSIS

Ventricular tachycardia (VT) portends high morbidity and mortality in cardiac sarcoidosis (CS). Left ventricular scarring in CS is often patchy with a predilection for the basal septum, anterior wall, and perivalvular regions. Reliable pre-procedural imaging modalities as adjuvant tools for VT scar localization are limited. To assess anatomic correlation of late iodine enhancement with procedural scar localization and to determine whether such correlation predicts ablation success. Consecutive VT ablation procedures from January 2017 to December 2020 at the Medical University of South Carolina were retrospectively reviewed. Thirteen patients with CS underwent pre-procedural computed tomography (CT) to identify wall thinning (WT) and late iodine enhancement (LIE). Left ventricular scarring was confirmed with voltage mapping and classified based on anatomical region: LV ostium, anterior, septal, inferior, lateral, and apical. Fisher's exact probability extension for 2 x 2 contingency tables were used to test whether there was significant congruency of two modalities. The cohort included 13 patients with CS (92% male, 60 +/- 11 years, EF 40.9% +/- 12.5). Average procedure time was 279 +/- 89 minutes with > 1 inducible VT per case (8 LBBB, 6 RBBB; average CL 414 ms) in all patients. The presence of WT did not correlate with LIE at the LV ostium (p=0.19) but did with anterior (p=0.007), inferior (p=0.005), and lateral (p=0.005) regions. WT was not associated with scar localization. The presence of LIE demonstrated convergence with scar localization at the LV ostium (p=0.005). Of 6 patients with normal wall thickness and positive LIE at the LV ostium (i.e. discordance), 5 (83%) had noninducible VT substrate post-ablation. Of those 5 patients, 3 (60%) had arrhythmia recurrence and required repeat ablation. In patients with cardiac sarcoidosis, LIE on CT correlates with scar localization at the LV summit. Ablation of LIE-identified LV ostial scars yields a high rate of acute success in patients with CS. Future studies should investigate the association between WT-LIE-scar localization and long-term outcomes.

Comparison of Transabdominal and Transvaginal Sonograms in Evaluation of Cervical Length During Pregnancy

Objective: A short cervix during pregnancy indicates a higher risk of preterm delivery. Transvaginal sonography is widely used for the detection of a short cervix. The literature indicates that 21–24 weeks is the most sensitive gestational age to assess transvaginal cervical length (TV CL) of ≤2.5 cm for potential preterm delivery. Pregnancies between 18 and 20 weeks’ gestation are generally performed transabdominally; thus, it could be beneficial to have a recognized correlation between the transabdominal cervical length (TA CL) measurement and the TV CL measurement at this earlier time period. Materials and Methods: An online database search produced 13 research articles to be reviewed. Inclusion criteria consisted of TA CL and TV CL assessment of singleton pregnancies with intact membranes. Results: Findings indicate high diagnostic yield when a TA CL of &lt;2.9 cm or TV CL of &lt;2.5 cm is used for defining a shortened cervix when measured between 18 and 20 weeks’ gestation. Conclusion: This review of the literature indicates a correlation between average TA CL and average TV CL measurements, although the relationship widens as CLs become shorter.

345 A Novel Study Exploring the Hidden Cost of Insufficient Investment in Computer Technology in a District General Hospital

Abstract Introduction The NHS’ move towards increasing digitisation is limited by inadequate resourcing. It is estimated 70% of a junior doctor’s time is spent completing computer-based administrative work. Aging and insufficient equipment leads to inefficiency. The objective of this study is to investigate the hidden cost of insufficient and poorly performing computer technology. Method Surveys were disseminated to doctors and data was collected regarding designation, ward, salary and estimated ‘minutes-waiting’ for computers to become free (CF) and to load (CL). Results 33 surveys were completed. The hospital-wide average CF and CL were 25 minutes and 31.06 minutes respectively, with a corresponding average daily cost per doctor of £10.16 (CF) and £12.63 (CL), totalling £22.79/doctor/day. In the highest-expense ward, CF (31.66 minutes) and CL (38.33 minutes) equated to £30.28/doctor/day. Following acquisition of new hardware and re-audit, CL was significantly reduced to 20.4 minutes (p = 0.0142). Conclusions This study highlights the hidden cost of insufficient, poorly performing hardware. Every day the total cost of time-wasted greatly surpasses the cost of a single computer unit, illustrating the false economy of reduced capital investment in computer technology.

Mapping QTL for leaf pigment content at dynamic development stage and analyzing Meta-QTL in rice

Leaf pigment content is a complicated quantitative trait which results from the cooperation of multiple related genes or quantitative trait loci (QTL) in rice. So far, more than 600 QTL for leaf pigment content has been reported. However, most QTL positions could not be directly compared with each other. In this study, our goal was to analyze consistent QTL regions affecting leaf pigment content by applying a genome wide QTL meta-analysis approach. 20 QTL related to leaf pigment content were detected at 5 different growth periods in 134 recombinant inbred lines (RILs) from a typical Indica-Japonica cross derived from PA64s and 9311 (two parents of super hybrid rice Liangyoupei 9). There was a candidate gene GLTP in the region of 3 QTL (qFS_Chla4, qFS_Chla+b4, and qFS_Car4), which related to component of chloroplast thylakoid membranes. After sequencing and qRT-PCR analysis, the gene showed significant difference in parents of the RILs. Meta-analysis was performed on 618 QTL collected from 38 previous studies. Consequently, a total of 64 MQTL (Meta-QTL) were obtained, of which 58.95% confidence intervals (CI) were smaller than the average Cl of the original QTL. In addition, 64 MQTL covered 6 of 20 QTL detected. Among them, four main QTL were included in 3 MQTL, and phenotypic variation of 21 MQTL was greater than 20%. The traits with higher number of QTL had higher number of MQTL, and candidate genes in overlapping MQTL include multiple effects. 7 candidate genes related to leaf pigment content were found in 4 MQTL spanning physical intervals < 0.5 Mb. These findings are not only anticipated to help molecular marker-assisted selection and pyramiding, but also contribute to determine candidate genes that regulate pigment content.

Contrasting Geochemistry of Apatite from Peridotites and Sulfide Ores of the Jinchuan Ni-Cu Sulfide Deposit, NW China

Abstract Apatite is present within both the hosting lherzolite and sulfide ore at the Jinchuan magmatic Ni-Cu sulfide deposit of northwest China. Apatite grains within the lherzolite are generally large and hexagonal (&amp;gt;200 μm) and are associated with interstitial phlogopite and amphibole. These apatite grains contain ~0.9 wt % F, ~1 wt % Cl, 6,800 to 14,500 ppm rare earth elements (REE) and have in situ δ18OV-SMOW values of 5.10 to 6.38‰, all of which are indicative of crystallization from an evolved silicate magma. In comparison, the massive and disseminated sulfide ores contain fine-grained apatite (&amp;lt;200 μm) that is associated with sulfide minerals, phlogopite, and albite. These apatite grains contain sulfide inclusions that are indicative of crystallization almost coevally with or slightly later than the sulfide minerals. They are Cl-rich apatite with an average Cl of 5.6 wt % but F concentrations are below the limit of detection. They contain 1,860 to 2,300 ppm REE and have in situ δ18OV-SMOW values of 5.62 to 6.47‰. These data suggest that the sulfide-associated apatite formed from F- and REE-depleted, Cl-bearing sulfide melts. The apatite within the lherzolite was overprinted by later hydrothermal fluids as evidenced by the presence of abundant rounded and needle-like monazite and rare allanite inclusions within the apatite that formed as a result of a coupled metasomatism-reprecipitation process shortly after crystallization. Altered and fresh apatite domains have similar δ18O values, suggesting that this alteration was induced by postmagmatic hydrothermal fluids. The apatite within the lherzolite and sulfide ore crystallized from two conjugate immiscible silicate and sulfide melts, respectively. Rare earth elements and F were preferentially partitioning into silicate melts, whereas most volatile components were mainly partitioned into the sulfide melts. The silicate magmas from which apatite crystallized were rich in light REE (LREE) relative to heavy REE (HREE). Volatile components in the sulfide melts changed the physicochemical conditions to enable such high-density melts to migrate upward and finally settle in the shallow chamber with silicate rocks.

Diffusion through soil-bentonite backfill from a constructed vertical cutoff wall

Diffusion coefficients were measured for soil-bentonite (SB) backfill sampled from a constructed vertical cutoff wall in Pennsylvania, USA. The backfill consisted of lean clay (the base soil) combined with bentonite-water slurry containing 5–6% sodium bentonite, resulting in a total bentonite content of ~1%. Ten dialysis leaching tests (DLTs) were conducted to measure apparent diffusion coefficients (Da) for chloride (Cl−) diffusion through the lean clay-bentonite backfill. In addition, model sand-bentonite backfills (total bentonite content = 4.7%) were prepared in the laboratory, and eight DLTs were performed for comparison with the field-sampled backfill and the diffusion literature. Both backfill types were tested with monovalent and divalent salt solutions (KCl and CaCl2), over a wide range of concentrations (60–350 mM). Despite the difference in bentonite content, values of Da were similar for the two backfills. Changes in Da with increasing average Cl− concentration were relatively minor, increasing by less than half an order of magnitude over the wide range of salt solutions, likely due to the low percentages of bentonite (<5%) in both backfills. Thus, for SB backfills with bentonite contents <5%, Da appears to be relatively insensitive to backfill composition, salt type and concentration.

What Role Do Chronic Workloads Play in the Acute to Chronic Workload Ratio? Time to Dismiss ACWR and Its Underlying Theory.

The aim of this study was to examine the associations between the injury risk and the acute (AL) to chronic (CL) workload ratio (ACWR) by substituting the original CL with contrived values to assess the role of CL (i.e., the presence and implications of statistical artefacts). Using previously published data, we generated a contrived ACWR by dividing the AL by fixed and randomly generated CLs, and we compared these results to real data. We also reproduced previously reported subgroup analyses, including dichotomising players' data above and below the median CL. Our analyses follow the same, previously published modelling approach. The analyses with original data showed effects compatible with higher injury risk for ACWR only (odd ratios, OR: 2.45, 95% CI 1.28-4.71). However, we observed similar effects by dividing AL by the "contrived" fixed and randomly generated CLs: OR 1.95 (1.18-3.52) dividing by 1510 (average CL); and OR ranging from 1.16 to 2.07, using random CL 1.53 (mean). Random ACWRs reducedthe variance relative to the original ALand further inflated the ORs (mean OR 1.89, from 1.42 to 2.70). ACWR causes artificial reclassification of players compared to AL alone. Finally, neither ACWR nor AL alone confer a meaningful predictive advantage to an intercept-only model, even within the training sample (c-statistic 0.574/0.544 vs. 0.5 in both ACWR/AL and intercept-only models, respectively). ACWR is a rescaling of the explanatory variable (AL, numerator), in turn magnifying its effect estimates and decreasing its variance despite conferring no predictive advantage. Other ratio-related transformations (e.g., reducing the variance of the explanatory variable and unjustified reclassifications) further inflate the OR of AL alone with injury risk. These results also disprove the etiological theory behind this ratio and its components. We suggest ACWR be dismissed as a framework and model, and in line with this, injury frameworks, recommendations, and consensus be updated to reflect the lack of predictive value of and statistical artefacts inherent in ACWR models.

Erosion Process and Temporal Variations in the Soil Surface Roughness of Spoil Heaps under Multi-Day Rainfall Simulation

The extensive artificially accelerated erosion of spoil heaps on newly engineered landforms is a key ecological management point requiring better understanding. Soil surface roughness is a crucial factor influencing erosion processes; however, study on spoil heap erosion with a view of surface roughness is lacking. This study investigated the erosion processes and the spatiotemporal variation of surface roughness on spoil heaps, and then, analyzed how the roughness affected the hydrological and sediment yield characteristics. Sequences of four artificial rainstorms with constant rainfall intensity (90 mm/h) were applied to cone-shaped spoil heaps (ground radius 3.5 m, height 2.3 m) of a loess soil containing 30 mass percent rock fragments. The surface elevation was sampled by a laser scanner. For the surface roughness indicators, the root mean square height (rmsh) and the correlation length (cl) increased sharply during the first rainfall event, and in the last three rainfall events, rmsh increased slightly and cl showed a relative decrease. The initial rmsh/cl of the whole slope surface ranged from 0.063 to 0.135, and increased with the rainfall sequence, thus, indicating that the spoil heap surface became rougher. Increasing soil roughness in the rainfall sequence delayed the initial runoff time and increased the runoff yield. The average runoff coefficient of the spoil heaps was 0.658. The average erosion rate of each rainfall event can be simulated by a regression equation of the corresponding average runoff rate and median cl (R-square of 0.816). Soil slumping with an average volume of 0.014 m3 occurred in the first two rainfall events, thus, significantly changing the roughness and peak instant erosion rate. Together, the results revealed the effects of surface roughness on the erosion of spoil heaps and would provide a useful reference for soil loss prediction and control.