Silicon uptake and isotope fractionation dynamics by crop species

That silicon is an important element in global bio-geochemical cycles is widely recognised. Recently, its relevance for global crop production has gained increasing attention in light of possible deficits in plant-available Si in soil. Silicon is beneficial for plant growth and is taken up in considerable amounts by crops like rice or wheat. However, plants differ in the way they take up silicic acid from soil solution, with some species rejecting silicic acid while others actively incorporate it. Yet because the processes governing Si uptake and regulation are not fully understood, these classifications are subject to intense debate. To gain a new perspective on the processes involved, we investigated the dependence of silicon stable isotope fractionation on silicon uptake strategy, transpiration, water use, and Si transfer efficiency. Crop plants with rejective (tomato, Solanum lycopersicum, and mustard, Sinapis alba) and active (spring wheat, Triticum aestivum) Si uptake were hydroponically grown for 6 weeks. Using inductively coupled plasma mass spectrometry, the silicon concentration and isotopic composition of the nutrient solution, the roots, and the shoots were determined We found that measured Si uptake does not correlate with the amount of transpired water and is thus distinct from Si incorporation expected for unspecific passive uptake. We interpret this lack of correlation to indicate a highly selective Si uptake mechanism. All three species preferentially incorporated light Si-28, with a fractionation factor 1000 x ln(alpha) of -0.33 parts per thousand (tomato), -0.55 parts per thousand (mustard), and -0.43 parts per thousand (wheat) between growth medium and bulk plant. Thus, even though the rates of active and passive Si root uptake differ, the physico-chemical processes governing Si uptake and stable isotope fractionation do not. We suggest that isotope fractionation during root uptake is governed by a diffusion process. In contrast, the transport of silicic acid from the roots to the shoots depends on the amount of silicon previously precipitated in the roots and the presence of active transporters in the root endodermis, facilitating Si transport into the shoots. Plants with significant biogenic silica precipitation in roots (mustard and wheat) preferentially transport silicon depleted in Si-28 into their shoots. If biogenic silica is not precipitated in the roots, Si transport is dominated by a diffusion process, and hence light silicon Si-28 is preferentially transported into the tomato shoots. This stable Si isotope fingerprinting of the processes that transfer biogenic silica between the roots and shoots has the potential to track Si availability and recycling in soils and to provide a monitor for efficient use of plant-available Si in agricultural production

Simultaneous preconcentration of 9Be and cosmogenic 10Be for determination of the 10Be/9Be ratio in (coastal) seawater

Beryllium isotopes have emerged as a quantitative tracer of continental weathering, but accurate and precise determination of the cosmogenic 10Be and stable 9Be in seawater is challenging, because seawater contains high concentrations of matrix elements but extremely low concentrations of 9Be and 10Be. In this study, we develop a new, time-efficient procedure for the simultaneous preconcentration of 9Be and 10Be from (coastal) seawater based on the iron co-precipitation method. The concentrations of 9Be, 10Be, and the resulting 10Be/9Be ratio for Changjiang Estuary water derived from the new procedure agree well with those obtained from the conventional procedure requiring separate preconcentration for 9Be and 10Be determinations. By avoiding the separate preconcentration, our newly developed procedure contributes toward more time-efficient handling of samples, less sample cross-contamination, and a more reliable 10Be/9Be ratio. Prior to this, we validated the iron co-precipitation method using artificial seawater and natural water samples from the Amazon Estuary regarding: (1) the “matrix effect” for Be analysis, (2) its extraction efficiency for pg g−1 levels Be in the presence and absence of organic matter, and (3) the data comparability with another preconcentration method. We calculated that for the determination of 9Be and 10Be in most open ocean seawater with typical 10Be concentrations of > 500 atoms g−1, good precisions (< 5%) can be achieved using less than 3 liters of seawater compared to more than 20 liters routinely used previously. Even for coastal seawater with extremely low 10Be concentration (e.g., 100 atoms g−1), we estimate a maximum amount of 10 liters to be adequate

The composition of amphibole phenocrysts in Neogene mafic volcanic rocks from the Puna plateau: Insights on the evolution of hydrous back-arc magmas

In typical Andean arc magmas, amphibole appears as a phenocryst phase only after considerable differentiation. However, some near-primitive volcanic rocks (high-Mg andesites and basalts) from monogenetic centers in the Puna plateau of Argentina also contain amphibole phenocrysts, implying special conditions of hydrous magma generation in this back-arc setting. This study documents typical examples from Southern and Northern Puna regions and uses the major and trace-element compositions of amphibole to constrain a petrogenetic model for the hydrous magmas. There are significant differences in the nature of amphiboles and their host lavas depending on location of the volcanic centers in the Southern and the Northern Puna regions. In the Southern Puna, basaltic andesitic lavas have Sr/Y values >40 and amphiboles show skeletal forms and occur in an assemblage with olivine and pyroxene. The amphibole compositions are relatively Al- and Ti-poor compared to the Northern Puna. Thermobarometry indicates amphibole crystallization temperatures of 960–1000 °C at moderate pressure (1000 °C) and pressures (6–8 kbar). Furthermore, the chemical composition of amphibole phenocrysts in the Northern Puna Campo Negro center suggests an alkaline affinity of the parental magmas which, together with radiogenic isotope data from earlier studies, indicates a significant contribution of the enriched lithosphere in the magma source. The new data collectively suggest high pressure evolution of hydrous magmas in the Southern Puna, whereas the Northern Puna magmas underwent more differentiation at higher levels in the crust. This contrast in the evolution history of magmas below both regions can be connected with their position relative to partial melting zones in the mid-upper crust, which are larger and longer-lived in the north than in the south, thus favoring a slower ascent of magmas in that region.Fil: Maro, Guadalupe. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Trumbull, Robert. German Research Centre for Geosciences; AlemaniaFil: Caffe, Pablo Jorge. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jofré, Cynthia Betina. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Filipovich, Ruben Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Frick, Daniel A.. German Research Centre for Geosciences; Alemani

A–C Estrogens as Potent and Selective Estrogen Receptor-Beta Agonists (SERBAs) to Enhance Memory Consolidation under Low-Estrogen Conditions

Estrogen receptor-beta (ERβ) is a drug target for memory consolidation in postmenopausal women. Herein is reported a series of potent and selective ERβ agonists (SERBAs) with in vivo efficacy that are A–C estrogens, lacking the B and D estrogen rings. The most potent and selective A–C estrogen is selective for activating ER relative to seven other nuclear hormone receptors, with a surprising 750-fold selectivity for the β over α isoform and with EC50s of 20–30 nM in cell-based and direct binding assays. Comparison of potency in different assays suggests that the ER isoform selectivity is related to the compound’s ability to drive the productive conformational change needed to activate transcription. The compound also shows in vivo efficacy after microinfusion into the dorsal hippocampus and after intraperitoneal injection (0.5 mg/kg) or oral gavage (0.5 mg/kg). This simple yet novel A–C estrogen is selective, brain penetrant, and facilitates memory consolidation

Tracking the State and Behavior of People in Response to COVID-1 19 Through the Fusion of Multiple Longitudinal Data Streams

The changing nature of the COVID-19 pandemic has highlighted the importance of comprehensively considering its impacts and considering changes over time. Most COVID-19 related research addresses narrowly focused research questions and is therefore limited in addressing the complexities created by the interrelated impacts of the pandemic. Such research generally makes use of only one of either 1) actively collected data such as surveys, or 2) passively collected data. While a few studies make use of both actively and passively collected data, only one other study collects it longitudinally. Here we describe a rich panel dataset of active and passive data from U.S. residents collected between August 2020 and July 2021. Active data includes a repeated survey measuring travel behavior, compliance with COVID-19 mandates, physical health, economic well-being, vaccination status, and other factors. Passively collected data consists of all locations visited by study participants, taken from smartphone GPS data. We also closely tracked COVID-19 policies across counties of residence throughout the study period. Such a dataset allows important research questions to be answered; for example, to determine the factors underlying the heterogeneous behavioral responses to COVID-19 restrictions imposed by local governments. Better information about such responses is critical to our ability to understand the societal and economic impacts of this and future pandemics. The development of this data infrastructure can also help researchers explore new frontiers in behavioral science. The article explains how this approach fills gaps in COVID-19 related data collection; describes the study design and data collection procedures; presents key demographic characteristics of study participants; and shows how fusing different data streams helps uncover behavioral insights

Evaluation of ‘the father effect’ media campaign to increase awareness of, and participation in, an online father-inclusive parenting program

There is substantial evidence that parenting programs are effective in improving parenting and child mental health outcomes. While there is increasing focus on delivering parenting interventions online to increase their reach and dissemination, fathers are underrepresented in all formats of parenting programs. However, research suggests that father participation is important for intervention effectiveness. This study evaluated the effectiveness of a media campaign for increasing awareness of, and participation in, an online father-inclusive parenting program called ‘ParentWorks’. An 8-week campaign was conducted in Australia via social media channels, digital display advertising, digital television, and radio. To assess the impact of the campaign, data were obtained from caregivers registering for ParentWorks during the campaign period (n = 848) and an 8-week comparison period that occurred 3 months later (n = 254). Additionally, a nationally representative sample of 2021 caregivers of children aged 2–16 years completed an online survey. Survey questions asked about exposure to the campaign, registration for participation in ParentWorks, and knowledge of the importance of father participation in parenting programs. Three times as many caregivers registered during the 8-week media campaign compared to the comparison period, and a significantly greater proportion of male caregivers registered in the campaign versus the comparison period. The online survey found that 11% of caregivers reported exposure to the campaign, and significantly more fathers than mothers reported exposure. Results showed that those who were exposed to the campaign were significantly more likely to endorse the importance of father participation in parenting programs, than those not exposed to the campaign. The findings indicate that media campaigns appear to be an effective method of increasing awareness of online parenting programs and enhancing rates of father involvement

Characterisation of Conventional 87Sr/86Sr Isotope Ratios in Cement, Limestone and Slate Reference Materials Based on an Interlaboratory Comparison Study

An interlaboratory comparison (ILC) was organised to characterise 87Sr/86Sr isotope ratios in geological and industrial reference materials by applying the so-called conventional method for determining 87Sr/86Sr isotope ratios. Four cements (VDZ 100a, VDZ 200a, VDZ 300a, IAG OPC-1), one limestone (IAG CGL ML-3) and one slate (IAG OU-6) reference materials were selected, covering a wide range of naturally occurring Sr isotopic signatures. Thirteen laboratories received aliquots of these six reference materials together with a detailed technical protocol. The consensus values for the six reference materials and their associated measurement uncertainties were obtained by applying a Gaussian, linear mixed effects model fitted to all the measurement results. By combining the consensus values and their uncertainties with an uncertainty contribution for potential heterogeneity, reference values ranging from 0.708134 mol mol-1 to 0.729778 mol mol-1 were obtained with relative expanded uncertainties of ≤ 0.007 %. This study represents an ILC on conventional 87Sr/86Sr isotope ratios, within which metrological principles were considered and the compatibility of measurement results obtained by MC-ICP-MS and by MC-TIMS is demonstrated. The materials characterised in this study can be used as reference materials for validation and quality control purposes and to estimate measurement uncertainties in conventional 87Sr/86Sr isotope ratio measurement

Hyperthermophilic Aquifex aeolicus initiates primer synthesis on a limited set of trinucleotides comprised of cytosines and guanines

The placement of the extreme thermophile Aquifex aeolicus in the bacterial phylogenetic tree has evoked much controversy. We investigated whether adaptations for growth at high temperatures would alter a key functional component of the replication machinery, specifically DnaG primase. Although the structure of bacterial primases is conserved, the trinucleotide initiation specificity for A. aeolicus was hypothesized to differ from other microbes as an adaptation to a geothermal milieu. To determine the full range of A. aeolicus primase activity, two oligonucleotides were designed that comprised all potential trinucleotide initiation sequences. One of the screening templates supported primer synthesis and the lengths of the resulting primers were used to predict possible initiation trinucleotides. Use of trinucleotide-specific templates demonstrated that the preferred initiation trinucleotide sequence for A. aeolicus primase was 5′-d(CCC)-3′. Two other sequences, 5′-d(GCC)-3′ and d(CGC)-3′, were also capable of supporting initiation, but to a much lesser degree. None of these trinucleotides were known to be recognition sequences used by other microbial primases. These results suggest that the initiation specificity of A. aeolicus primase may represent an adaptation to a thermophilic environment

Keeping parents involved: Predicting attrition in a self-directed, online program for childhood conduct problems

Positive parenting programs have a strong evidence base for improving parent–child relationships, strengthening families, and reducing childhood behavior disturbances. Their reach is less than optimal however, with only a minority of families in need of help participating. Father involvement is particularly low. Online, self-directed programs have the potential to improve participation rates. This article examines risk factors for dropout/attrition from a free, evidence-based, self-directed, father-inclusive parenting program, Parentworks, which was made available across Australia. Parents (N = 2,967) enrolled in the program and completed preintervention questionnaires. There was a steady and consistent loss of participants through the sequence of core program modules, until a final sample of 218 completed the postintervention questionnaire. A range of demographic and parent and child variables were tested as predictors of 3 subgroups: nonstarters, partial completers, and full completers. Nonstarters (n = 1,625) tended to have older children with fewer behavioral problems and report higher psychopathology and dysfunctional parenting than those who partially (n = 1,124) or fully completed. Contrary to findings from face-to-face research, single parents had the highest completion rates. Coparticipation of partners and interparental conflict had no impact on completion rates. Fathers participated at relatively high levels. Results show that parents with the greatest need tend to engage with online programs, and online programs may be particularly useful for fathers, single parents, and those in conflicted relationships. Directions for future program design and research are discussed