Relative Production Rates Research Articles

Global Probabilistic Forecasting for Multiple Tight Gas Wells Using Deep Autoregressive Networks

Summary Traditional methods for forecasting production rate, such as Arps, analytical techniques, and recurrent neural network (RNN)–based deep learning, are mainly point prediction techniques developed within the framework of single-well forecasting. These methods often face limitations stemming from single-well historical production data and model assumptions, hindering their ability to consider the influence of development patterns of other production wells within the block on the target well. In addition, they struggle to predict the multiple production rate time series simultaneously and often fail to quantify uncertainty in predictions or adequately exploit extensive relevant historical production data. To tackle these challenges, we propose a model based on the deep autoregressive recurrent neural network (DeepAR), leveraging related multiwell production rate data to enable global modeling and probabilistic forecasting. This model incorporates dynamic covariate and static categorical variable data, integrating Bayesian inference and using gradient descent algorithms and maximum likelihood estimation methods to derive a comprehensive historical-future production probability evolution pattern shared across multiple wells. Leveraging data from 943 tight gas wells, a comprehensive evaluation of the DeepAR model’s performance was undertaken, encompassing the comparison of prediction accuracy with long short-term memory (LSTM), classification prediction, cold-start prediction, and single-well multitarget prediction scenarios, summarizing the applicability conditions for each. The research findings highlight that DeepAR integrates the acquired comprehensive production probability evolution pattern with specific production historical data of the target well to formulate a “comprehensive + specific” production probability prediction approach, resulting in improved stability and accuracy. On average, DeepAR demonstrates a 58.79% reduction in normalized deviation (ND) compared to the LSTM model, showcasing enhanced stability, particularly in scenarios involving frequent well shut-ins and openings. Moreover, DeepAR can learn static categorical features, with the classification model resulting in a 27.15% reduction in the ND compared to the unclassified model. Furthermore, DeepAR adeptly addresses the challenge of limited data availability, achieving cold-start prediction and facilitating multitarget single-well training and prediction while considering the interdependency among multiple variables over time and effectively mitigating the issue of missing auxiliary variables during the prediction phase. This study contributes to a broader understanding of production forecasting and analysis of production dynamics methods from a big data perspective.

Forward J/ψ+J/ψ and J/ψ+ψ′ production with high-energy factorization

We calculate the cross sections of associated J/ψ+ψ′ and J/ψ+J/ψ production in pp collisions at s=13 TeV in the forward kinematic region. The high-energy factorization (kT-factorization) framework supplemented with the Catani-Ciafaloni-Fiorani-Marchesini evolution of gluon densities in a proton is applied. We demonstrate that the latest data on J/ψ+J/ψ production and first experimental data on J/ψ+ψ′ events taken very recently by the LHCb Collaboration can be described well by the color singlet terms and contributions from double parton scattering (DPS) with the standard choice for σeff parameter. The relative production rate σ(J/ψ+ψ′)/σ(J/ψ+J/ψ) is found to be sensitive to the DPS terms as well as to feeddown contributions. Published by the American Physical Society 2024

Linking PAHs concentration, risk to PAHs source shift in soil and water in epikarst spring systems, Southwest China

A systematic assessment of the variations in the ecological risk of PAHs and the key emission sources controlling the variations is of great importance to human health and aquatic organisms. PAH concentrations, composition, source, and ecological risk in soils and water in two different periods (2010–2011 and 2019) of three typical epikarst springs in Southwest China were investigated. Results showed that PAH concentrations in soil and water have an overall downward trend (a reduction of 57 % and 93 %, respectively) in the past 10 years, which is consistent with the downward trend in the relative contribution rate of raw coal production (a 66 % reduction). In terms of composition, the proportion of low-ring PAHs decreased, medium-ring and high-ring PAHs increased in the soil profile. The proportion of low-ring PAHs did not change obviously, the proportion of medium-ring PAHs increased, and the proportion of high-ring PAHs decreased in epikarst springs. The source of PAHs changed remarkably over time, the relative contribution of coal combustion to PAHs decreased from 38 % to 20 %, and the vehicle contribution of PAHs increased from 31 % to 44 % in soils. The relative contribution rate of unburned oil and coke oven and biomass combustion change is less. Furthermore, the ecological risk of PAHs in the soils was reduced from moderate risk 2 to moderate risk 1, the risk in epikarst spring was reduced from high risk to moderate risk 2 after 10 years. This study demonstrates that substituting petroleum and coal with green energies can reduce PAH concentrations and risk.

Charmonium production in pNe collisions at sqrt{s_{scriptscriptstyle text {NN}}} =68.5 GeV

The measurement of charmonium states produced in proton-neon (ptext {Ne}) collisions by the LHCb experiment in its fixed-target configuration is presented. The production of {{J} hspace{-1.66656pt}/hspace{-1.111pt}psi } and psi {(2S)} mesons is studied with a beam of 2.5mathrm{,Tehspace{-1.00006pt}V} protons colliding on gaseous neon targets at rest, corresponding to a nucleon-nucleon centre-of-mass energy sqrt{s_{scriptscriptstyle text {NN}}} =68.5mathrm{,Gehspace{-1.00006pt}V} . The data sample corresponds to an integrated luminosity of 21.7pm 1.4 nb^{-1}. The {{J} hspace{-1.66656pt}/hspace{-1.111pt}psi } and psi {(2S)} hadrons are reconstructed in mu ^+mu ^- final states. The {{J} hspace{-1.66656pt}/hspace{-1.111pt}psi } production cross-section per target nucleon in the centre-of-mass rapidity range y^star in [-2.29, 0] is found to be 506 pm 8 pm 46 text { nb/nucleon}. The ratio of {{J} hspace{-1.66656pt}/hspace{-1.111pt}psi } and D^0 cross-sections is evaluated to (1.06 pm 0.02 pm 0.09)%. The psi {(2S)} to {{J} hspace{-1.66656pt}/hspace{-1.111pt}psi } relative production rate is found to be (1.67 pm 0.27pm 0.10)% in good agreement with other measurements involving beam and target nuclei of similar sizes.

More Accurate Method for Evaluating the Activity of Photocatalytic Hydrogen Evolution and Its Reaction Kinetics Equation.

Photocatalytic water splitting to hydrogen is a sustainable energy conversion method. However, there is a lack of sufficiently accurate measurement methods for an apparent quantum yield (AQY) and a relative hydrogen production rate (rH2) at the moment. Thus, a more scientific and reliable evaluation method is highly required to allow the quantitative comparison of photocatalytic activity. Herein, a simplified kinetic model of photocatalytic hydrogen evolution was established, the corresponding photocatalytic kinetic equation was deduced, and a more accurate calculation method is proposed for the AQY and the maximum hydrogen production rate vH2,max. At the same time, new physical quantities, absorption coefficient kL and specific activity SA, were proposed to sensitively characterize the catalytic activity. The scientificity and practicality of the proposed model and the physical quantities were systematically verified from the theoretical and experimental levels.

Production of volatile organic iodine compounds by the marine cyanobacterium Calothrix parasitica under different light intensities

Volatile organic iodine compounds (VOICs) that exist in the marine environment, such as diiodomethane (CH2I2), chloroiodomethane (CH2ClI), and bromoiodomethane (CH2BrI), are known to transport iodine from the ocean to the atmosphere. These VOICs play important roles in various atmospheric chemistry processes, such as ozone decomposition. So far, marine phytoplankton such as diatoms and chlorarachniophytes have been reported to produce these VOICs in the culture experiments. In this study, we examined the production of VOICs by the marine cyanobacterium Calothrix parasitica NIES-267 (axenic) cultured at 24 °C for several weeks. The effect of light intensity on the production of VOICs was also studied by irradiating the culture medium of C. parasitica with light at intensities of 60, 90, and 120 μmol photons m−2 s−1. In addition, incubation experiments with 13CH2I2 added to the culture medium were performed to evaluate the decrease of 13CH2I2 due to photolysis during incubation. The concentrations of VOICs in the culture medium were measured using a purge-and-trap gas chromatograph-mass spectrometer. The concentrations of VOICs in the culture medium increased during the exponential or stationary phase at each light intensity. During the exponential phase, the chlorophyll a-normalized production rates of CH2ClI and CH2BrI increased with increasing light intensity from 60 to 120 μmol photons m−2 s−1, while the chlorophyll a-normalized maximum production rate of CH2I2 was found to be 28 pmol (μg chlorophyll a) −1 d−1 at 90 μmol photons m−2 s−1. During the incubation period, 13CH2I2 was photodegraded by about 17% at 120 μmol photons m−2 s−1. The relative production rates were CH2I2 > CH2ClI > CH2BrI for all light conditions, and the relative amount of CH2I2 tended to decrease under high light intensity conditions (120 μmol photons m−2 s−1). These results suggest that the cyanobacterium C. parasitica could be one of the significant sources of VOICs such as CH2I2 in the marine environment, and that light intensity would be an important factor in estimating VOICs emissions from marine cyanobacteria.

Hidden-charm pentaquark states through current algebra: from their production to decay * *Supported by the National Natural Science Foundation of China (11722540, 12075019), the Jiangsu Provincial Double-Innovation Program (JSSCRC2021488), and the Fundamental Research Funds for the Central Universities

There may be seven hadronic molecular states. We construct their corresponding interpolating currents and calculate their masses and decay constants using QCD sum rules. Based on these results, we calculate their relative production rates in decays using current algebra, that is, , where and are two different states. We also study their decay properties via Fierz rearrangement and further calculate these ratios in the mass spectrum, that is, . Our results suggest that the molecular states of and may be observed in future experiments.

Probing the Effects of Defects in Ultrathin Oxide Overlayers on the Selectivity of Encapsulated Electrocatalysts

Application of ultrathin oxide encapsulation layers on co-catalysts employed in z-scheme photocatalysis has the potential to increase overall efficiency through the prevention of undesirable back reactions and increased charge separation. [1,2] However, defects within the semipermeable oxide coatings – such as pinholes, cracks or particle protrusions – have been postulated to facilitate locally high rates of undesirable reactions by creating pathways for facile transport of undesired reactants to exposed active sites.[3] Local probe measurements, such as scanning electrochemical microscopy (SECM), can estimate the relative rates of production of product species generated from competing electrochemical reactions with high spatial resolution over the electrode. This can be leveraged to determine the influence of local defects on global performance metrics, such as the apparent permeability of the overlayer and selectivity of the electrode. In this presentation, we report the use of SECM to determine the influence of overlayer defects on the performance of a model silicon oxide (SiOx) -encapsulated Pt thin film electrocatalyst when operated under conditions where two competing reactions can occur. Motivated by Z-scheme photocatalysis, the hydrogen evolution reaction (HER) and Fe(III)/Fe(II) redox reaction were studied. After introducing new methodology to determine local selectivity towards HER using SECM tip current, the resulting selectivity maps are compared against defects seen in optical images, scanning electron micrographs, and atomic force microscopy images. This analysis reveals that that certain types of defects in the oxide overlayer can be responsible for a large percentage of the partial current density towards the undesired Fe(III) reduction reaction. Correcting for the defect contributions to the undesired reaction, it is determined that the true Fe(III) permeability values for the SiOx overlayers are almost two orders of magnitude lower than permeabilities determined from conventional analysis that ignored the presence of defects. Finally, different types of defects were studied revealing that the defect morphology can have varying influence on both the selectivity and calculated permeability. This work highlights the need for local measurements in addition to macroscopic measurements of oxide encapsulated catalysts as they are applied to more complex geometries such as particle photocatalysts.

Hadronic molecules in B decays

There are eighteen possibly existing $D^{(*)} \bar D^{(*)}$, $D^{(*)} \bar K^{(*)}$, and $D^{(*)} D_s^{(*)-}$ hadronic molecular states. We construct their corresponding interpolating currents, and calculate their masses and decay constants using QCD sum rules. Based on these results, we calculate their relative production rates in $B$ and $B^*$ decays through the current algebra, and calculate their relative branching ratios through the Fierz rearrangement, as summarized in Table III. Our results support the interpretations of the $X(3872)$, $Z_c(3900)$, $Z_c(4020)$, and $X_0(2900)$ as the molecular states $D \bar D^*$ of $J^{PC} = 1^{++}$, $D \bar D^*$ of $J^{PC} = 1^{+-}$, $D^* \bar D^*$ of $J^{PC} = 1^{+-}$, and $D^* \bar K^*$ of $J^P = 0^{+}$, respectively. Our results also suggest that the $Z_{cs}(3985)$, $Z_{cs}(4000)$, and $Z_{cs}(4220)$ are strange partners of the $X(3872)$, $Z_c(3900)$, and $Z_c(4020)$, respectively. In the calculations we estimate the lifetime of a weakly-coupled composite particle $A = |BC\rangle$ to be $1/t_A \approx 1/t_B + 1/t_C + \Gamma_{A \to BC} + \cdots$, with $\cdots$ partial widths of other possible decay channels.

The biotechnological potential of microbial communities from Antarctic soils and sediments: Application to low temperature biogenic methane production

Anaerobic digestion (AD) is an attractive bioprocess for waste treatment and energy recovery through methane-rich biogas production. Under temperate to cold climate, the implementation of AD for low-organic load wastewater treatment has been limited to date, due to the energetic and economic cost of maintaining optimal mesophilic temperature. Hence, we aim at (i) exploring the biotechnological potential of a microbial inoculum from Antarctic soils and sediments to run AD at low temperatures; and (ii) evaluating the effect of temperature over a psychrophilic-mesophilic range on both methane production rates and microbial community composition. Methane production stimulated by acetate amendment was detected from 5 to 37 °C, with a maximum at 25 °C, corresponding to the highest relative abundance of methanogenic archaea (c. 21.4% of the total community). From 5 to 25 °C, the predominant methanogen was Methanosaeta, while it shifted to Methanocorpusculum at 30 °C. Compared with an industrial mesophilic sludge, the relative methane production rate at 5 °C (compared to the maximum) was 40% greater in the Antarctic inoculum. Microbial communities from permanently cold Antarctic sediments efficiently produce methane at low temperatures revealing a biotechnological potential for the treatment of low-organic load residues in cold regions.

A newly emerging alphasatellite affects banana bunchy top virus replication, transcription, siRNA production and transmission by aphids.

Banana bunchy top virus (BBTV) is a six-component ssDNA virus (genus Babuvirus, family Nanoviridae) transmitted by aphids, infecting monocots (mainly species in the family Musaceae) and likely originating from South-East Asia where it is frequently associated with self-replicating alphasatellites. Illumina sequencing analysis of banana aphids and leaf samples from Africa revealed an alphasatellite that should be classified in a new genus, phylogenetically related to alphasatellites of nanoviruses infecting dicots. Alphasatellite DNA was encapsidated by BBTV coat protein and accumulated at high levels in plants and aphids, thereby reducing helper virus loads, altering relative abundance (formula) of viral genome components and interfering with virus transmission by aphids. BBTV and alphasatellite clones infected dicot Nicotiana benthamiana, followed by recovery and symptomless persistence of alphasatellite, and BBTV replication protein (Rep), but not alphasatellite Rep, induced leaf chlorosis. Transcriptome sequencing revealed 21, 22 and 24 nucleotide small interfering (si)RNAs covering both strands of the entire viral genome, monodirectional Pol II transcription units of viral mRNAs and pervasive transcription of each component and alphasatellite in both directions, likely generating double-stranded precursors of viral siRNAs. Consistent with the latter hypothesis, viral DNA formulas with and without alphasatellite resembled viral siRNA formulas but not mRNA formulas. Alphasatellite decreased transcription efficiency of DNA-N encoding a putative aphid transmission factor and increased relative siRNA production rates from Rep- and movement protein-encoding components. Alphasatellite itself spawned the most abundant siRNAs and had the lowest mRNA transcription rate. Collectively, following African invasion, BBTV got associated with an alphasatellite likely originating from a dicot plant and interfering with BBTV replication and transmission. Molecular analysis of virus-infected banana plants revealed new features of viral DNA transcription and siRNA biogenesis, both affected by alphasatellite. Costs and benefits of alphasatellite association with helper viruses are discussed.

Identification of potential regulators of cell production and early fruit growth in apple (Malus × domestica Borkh.)

Fruit size is a commercially valuable trait that is determined by the extent of fruit growth. In apple, (Malus × domestica Borkh.), early fruit growth is facilitated by intensive cell production, but mechanisms regulating these processes are not well understood. In this study, members of five gene families involved in growth regulation were identified and evaluated in apple: AUXIN-REGULATED GENE INVOLVED IN ORGAN SIZE (ARGOS); CELL NUMBER REGULATOR (CNR); GROWTH REGULATING FACTOR (GRF); GRF INTERACTING FACTOR (GIF); and KLUH. MdARGOS1 and MdARGOS2 transcript abundance was higher during early fruit growth but was also enhanced by up to 18-fold under conditions of reduced cell production during flower and fruit development, indicating that their gene products play complex roles in regulating growth mechanisms during early development. MdCNR20a and MdCNR20b transcript abundance decreased during early fruit growth and increased during the transition from cell production to cell expansion. MdCNR20a transcript abundance was negatively correlated with the relative cell production rate (RCPR; ρ = - 0.82; P = 0.002), was enhanced in response to shading, and reduced in response to lower fruit load, indicating that it's gene product negatively regulates cell production and early fruit growth. Transcript abundance of MdGRF11 and MdGRF16 was greater during cell production-mediated fruit growth, and higher in the cortex than in the pith. MdGIF3 transcript abundance was greater during early fruit development, higher in the cortex, enhanced under reduced fruit load conditions, and strongly correlated with RCPR (ρ = 0.93; P < 0.0001). Further, it was correlated with that of MdGRF11 and MdGRF16 (ρ = 0.87 and 0.89, respectively; P < 0.0001), indicating that the GRF11/16-GIF3 module is co-regulated and involved in spatio-temporal regulation of cell production and fruit growth. Transcript abundance of MdKLUH1 was low and not consistent with a role in regulating cell production and fruit growth. Together, this study demonstrates coordinated control of cell production during early fruit growth by multiple regulatory components, identifies candidates for functional characterization, and provides potential tools for enhancing growth of the apple fruit.

Discriminating the heavy jet production mechanisms in associated Z + heavy flavor events at the LHC

We reconsider the associated Z boson and charm or beauty jet production at the LHC by paying special attention to the formation dynamics of heavy jets. Two different approaches are studied: first one, where heavy quarks are produced in the hard scattering subprocesses, implemented in the Monte-Carlo generator pegasus, and another method, where the hard scattering is calculated at NLO with MadGraph5_aMC@NLO and TMD parton shower is included (implemented in the Monte-Carlo generator Cascade3). We compare the predictions obtained in both schemes with latest experimental data for associated Z + b production cross sections and the relative production rate sigma (Z + c)/sigma (Z + b) collected by the ATLAS and CMS Collaborations at sqrt{s} = 13 TeV. We introduce two kinematic observables (denoted as z_b and p_T^mathrm{rel}) which can be used to discriminate between the heavy jet production mechanisms. Using these variables we trace the shape of the simulated b-jet events and recommend that these observables be taken into consideration in the forthcoming experimental analyses.

Fertilización de dos grupos genéticos de Pinus patula Schiede ex Schltdl. &amp; Cham. en un ensayo de progenies de cuatro años

Introduction: Genetic improvement and nutritional management are used to increase productive capacity. Objective: To analyze the effect of traditional and controlled-release fertilizers, as well as the way to define the doses (technically or empirically), on growth of 20 tree families of Pinus patulaSchiede ex Schltdl. &amp; Cham. Materials and methods: Four fertilization treatments were applied: 1) control; 2) “technical”, based on foliar analysis; 3) controlled release (18-6-12 + 2CaO + 3.5 Mg + 2.1 Si + microelements); and 4) mixture of agricultural fertilizers in nutrient concentrations similar to the controlled-release treatment. Height, diameter, biomass index, number of whorls, leaf mass, and growth initiation and cessation were evaluated in a group of 10 superior and 10 inferior three-year old families in Chignahuapan, Puebla. Data were analyzed with the MIXED procedure of SAS. Results and discussion: Trees showed no significant differences in growth, biomass production and growth initiation by fertilization effect, but showed significant differences by genetic quality (P ≤ 0.05). The genotype*fertilization interaction was significant; after one year of controlled-release fertilizer application, inferior genotypes had the highest values of relative rates of biomass production, diameter at root collar and height. Conclusions: Controlled-release fertilizers at appropriate doses and environmental conditions are a viable option to promote growth of young P. patula trees in the field.

Observation of excited Ωc0 baryons in Ωb−→Ξc+K−π− decays

The first observation of the $\Omega_b^- \to \Xi_c^+ K^- \pi^-$ decay is reported using $pp$ collision data at centre-of-mass energies of 7, 8 and 13\,$\mathrm{TeV}$ collected by the LHCb experiment, corresponding to an integrated luminosity of 9\,$\mathrm{fb}^{-1}$. Four excited $\Omega_c^0$ baryons are observed in the $\Xi_c^+ K^-$ mass projection of the $\Omega_b^- \to \Xi_c^+ K^- \pi^-$ decays with the significance of each exceeding five standard deviations. They coincide with the states previously observed in prompt \proton\proton and $e^+e^-$ production. Relative production rates, masses and natural widths of the states are measured, and a test of spin hypotheses is performed. Moreover, the branching ratio of $\Omega_b^- \to \Xi_c^+ K^- \pi^-$ is measured relative to the $\Omega_b^- \to \Omega_c^0 \pi^-$ decay mode and a precise measurement of the $\Omega_b^-$ mass of \mbox{$6044.3 \pm 1.2 \pm 1.1^{\,+0.19}_{\,-0.22}\,\mathrm{MeV}$} is obtained.

Sensitive detection of Plasmodium vivax malaria by the rotating-crystal magneto-optical method in Thailand

The rotating-crystal magneto-optical detection (RMOD) method has been developed for the rapid and quantitative diagnosis of malaria and tested systematically on various malaria infection models. Very recently, an extended field trial in a high-transmission region of Papua New Guinea demonstrated its great potential for detecting malaria infections, in particular Plasmodium vivax. In the present small-scale field test, carried out in a low-transmission area of Thailand, RMOD confirmed malaria in all samples found to be infected with Plasmodium vivax by microscopy, our reference method. Moreover, the magneto-optical signal for this sample set was typically 1–3 orders of magnitude higher than the cut-off value of RMOD determined on uninfected samples. Based on the serial dilution of the original patient samples, we expect that the method can detect Plasmodium vivax malaria in blood samples with parasite densities as low as sim5–10 parasites per microliter, a limit around the pyrogenic threshold of the infection. In addition, by investigating the correlation between the magnitude of the magneto-optical signal, the parasite density and the erythrocytic stage distribution, we estimate the relative hemozoin production rates of the ring and the trophozoite stages of in vivo Plasmodium vivax infections.

Quantitative Control for Stoichiometric Protein Synthesis

Bacterial protein synthesis rates have evolved to maintain preferred stoichiometries at striking precision, from the components of protein complexes to constituents of entire pathways. Setting relative protein production rates to be well within a factor of two requires concerted tuning of transcription, RNA turnover, and translation, allowing many potential regulatory strategies to achieve the preferred output. The last decade has seen a greatly expanded capacity for precise interrogation of each step of the central dogma genome-wide. Here, we summarize how these technologies have shaped the current understanding of diverse bacterial regulatory architectures underpinning stoichiometric protein synthesis. We focus on the emerging expanded view of bacterial operons, which encode diverse primary and secondary mRNA structures for tuning protein stoichiometry. Emphasis is placed on how quantitative tuning is achieved. We discuss the challenges and open questions in the application of quantitative, genome-wide methodologies to the problem of precise protein production.

Insights into secondary ion formation during dynamic SIMS analysis: Evidence from sputtering of laboratory synthesized uranium compounds with a high-energy O− primary beam on a NanoSIMS 50L

We investigate the sputtering and ionization process that takes place during secondary ion mass spectrometry (SIMS) analysis in order to develop a better understanding of the underlying controls on elemental and molecular oxide secondary ion yields. Using data from a suite of uranium compounds that were sputtered with an O- primary beam on a NanoSIMS 50L, our goal is to understand whether a compound’s intrinsic properties, or processes operating at the sputtering site, exert the greatest influence over the relative abundances of uranium elemental and molecular oxide secondary ions observed during an analysis. While the observed 238U/238U16O and 238U/238U16O2 of the various compounds exhibit considerable overlap, there are relationships between the weighted mean 238U/238U16O and 238U/238U16O2 ratios for the various compounds and their enthalpies of formation. This reinforces the existing theory that the nature of the material being sputtered can influence relative ion yields (e.g. the SIMS matrix effect), but we also document significant evidence for the influence of processes operating at the sputtering site as a major factor. The existence of a strong relationship between the relative uranium molecular oxide production rate and the mass fractionation regimes taking place within an analysis, as well as the existence of sudden shifts in molecular oxide production rates taking place within an analysis, provide further evidence for the importance of processes related to the sputtering and ionization dynamics as exerting the most control over observed ion yields. Evaluation of our data within the context of existing models for secondary ion production during SIMS analysis highlights the need for additional models that consider the competing influences of a sample’s chemical and/or structural form, reactions taking place at the sputtering site, as well as the ionization and ion extraction dynamics of the various elemental and molecular oxide species.

Effect of Humic Acid on Tolerance indexes of Barley plant to Cadmium Toxicity

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; This study was carried out to evaluate the effect of different levels of Humic acid (0, 400, 800 ppm) on tolerance index of barley plant to different levels (0, 25, 50 and 100 ppm) of Cadmium. The experiment was designed according factorial completely randomized design with three replications. The results revealed that the combination effect of Humic acid and Cadmium significantly increased the total dry weight, number of spikes and dry weight of straw, as well as in total dry weight of plant, cadmium tolerance was found by treatments HA0CD50, HA0CD10, HA400CD0, HA400CD25, HA400CD100, HA800CD50, HA800CD100. Cadmium significantly decreased the relative chlorophyll production rate (RCPR) of Barley plant,

Time series analysis and mechanistic modelling of heterogeneity and sero-reversion in antibody responses to mild SARS‑CoV-2 infection.

BackgroundSARS-CoV-2 serology is used to identify prior infection at individual and at population level. Extended longitudinal studies with multi-timepoint sampling to evaluate dynamic changes in antibody levels are required to identify the time horizon in which these applications of serology are valid, and to explore the longevity of protective humoral immunity.MethodsHealthcare workers were recruited to a prospective cohort study from the first SARS-CoV-2 epidemic peak in London, undergoing weekly symptom screen, viral PCR and blood sampling over 16–21 weeks. Serological analysis (n =12,990) was performed using semi-quantitative Euroimmun IgG to viral spike S1 domain and Roche total antibody to viral nucleocapsid protein (NP) assays. Comparisons were made to pseudovirus neutralizing antibody measurements.FindingsA total of 157/729 (21.5%) participants developed positive SARS-CoV-2 serology by one or other assay, of whom 31.0% were asymptomatic and there were no deaths. Peak Euroimmun anti-S1 and Roche anti-NP measurements correlated (r = 0.57, p<0.0001) but only anti-S1 measurements correlated with near-contemporary pseudovirus neutralising antibody titres (measured at 16–18 weeks, r = 0.57, p<0.0001). By 21 weeks’ follow-up, 31/143 (21.7%) anti-S1 and 6/150 (4.0%) anti-NP measurements reverted to negative. Mathematical modelling revealed faster clearance of anti-S1 compared to anti-NP (median half-life of 2.5 weeks versus 4.0 weeks), earlier transition to lower levels of antibody production (median of 8 versus 13 weeks), and greater reductions in relative antibody production rate after the transition (median of 35% versus 50%).InterpretationMild SARS-CoV-2 infection is associated with heterogeneous serological responses in Euroimmun anti-S1 and Roche anti-NP assays. Anti-S1 responses showed faster rates of clearance, more rapid transition from high to low level production rate and greater reduction in production rate after this transition. In mild infection, anti-S1 serology alone may underestimate incident infections. The mechanisms that underpin faster clearance and lower rates of sustained anti-S1 production may impact on the longevity of humoral immunity.FundingCharitable donations via Barts Charity, Wellcome Trust, NIHR.