The protoliths of central Himalayan eclogites

Eclogites represent the highest pressure conditions yet observed from rocks thrust to the surface in the central Himalaya. A detailed investigation of the protolith nature of these eclogites is needed to better understand pre-Himalayan geological history. Retrogressed eclogites were collected from Thongmön (Dingri County) and Riwu (Dinggye County), central Himalaya, China. We investigated the bulk rock major and trace elements, Sr-Nd isotopes, zircon geochronology, and Hf-O isotopes. These retrogressed eclogites experienced five stages of metamorphic evolution from prograde amphibolite-facies to peak eclogite-facies, and high pressure granulites-facies, granulites-facies then final amphibolite-facies overprinting during exhumation. Geochemically, they are subalkaline basalts with high FeO contents and a tholeiitic affinity; trace elements show similarities with enriched mid-ocean ridge basalts. Bulk rocks have a wide range of εNd(t) values from −0.24 to +7.08, and an unusually wide range of initial 87Sr/86Sr ratios of 0.705961−0.821182. Zircon relict magmatic cores from both Thongmön and Riwu eclogites yield a consistent protolith age of ca. 1850 Ma, with enriched heavy rare earth element patterns and significant negative Eu anomalies. These relict cores have oxygen isotopes signatures of δ18O = 5.8−8.1‰, εHf(t) values of −4.85 to +9.59, and two-stage model ages (TDM2) of 1.91−2.81 Ga. Metamorphic overgrowth zircons yield much younger ages of ca. 14 Ma. Integration of all of the above data suggests that the protolith of these central Himalayan retrogressed eclogites might be Proterozoic continental flood basalts of the North Indian Plate, generated under a post-collisional extension setting during the assembly of the Columbia Supercontinent. Occurrence of both Neoproterozoic−early Paleozoic rocks and ca. 1.85 Ga rocks in the regional crystalline rocks may reflect either unrecognized sub-horizontal Main Central Thrust exposure(s) or exhumation of a deeply cut part of the Greater Himalayan Crystalline complex. In combination with previous reports of Late Cretaceous, Neoproterozoic, and similar but younger Paleoproterozoic protolith, it is clear that the central Himalayan eclogites originate from multiple sources of protolith.

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Native Plant Capacity for Gentle Remediation in Heavily Polluted Mines

Applied Sciences ◽

10.3390/app11041769 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1769

Author(s):

María Noelia Jiménez ◽

Gianluigi Bacchetta ◽

Francisco Bruno Navarro ◽

Mauro Casti ◽

Emilia Fernández-Ondoño

Keyword(s):

Trace Elements ◽

Plant Species ◽

Contaminated Soils ◽

Aerial Part ◽

Bioaccumulation Factor ◽

Native Plant ◽

Dittrichia Viscosa ◽

Wide Range ◽

Cistus Salviifolius ◽

Plant Capacity

The use of plant species to stabilize and accumulate trace elements in contaminated soils is considered of great usefulness given the difficulty of decontaminating large areas subjected to mining for long periods. In this work, the bioaccumulation of trace elements is studied by relating the concentrations in leaves and roots of three plants of Mediterranean distribution (Dittrichia viscosa, Cistus salviifolius, Euphorbia pithyusa subsp. cupanii) with the concentrations of trace elements in contaminated and uncontaminated soils. Furthermore, in the case of D. viscosa, to know the concentration of each element by biomass, the pool of trace elements was determined both in the aerial part and in the roots. The bioaccumulation factor was not high enough in any of the species studied to be considered as phytoextractors. However, species like the ones studied in this work that live on soils with a wide range of concentration of trace elements and that develop a considerable biomass could be considered for stabilization of contaminated soils. The plant species studied in this work are good candidates for gentle-remediation options in the polluted Mediterranean.

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Memories of Tiananmen

10.5117/9789463728447 ◽

2021 ◽

Author(s):

Francis Lee ◽

Joseph Man Chan

Keyword(s):

Hong Kong ◽

Collective Memory ◽

Digital Media ◽

Political Communication ◽

Civil Liberties ◽

Significant Degree ◽

Historical Period ◽

Multiple Sources ◽

News Reports ◽

Wide Range

This book analyzes how collective memory regarding the 1989 Beijing student movement and the Tiananmen crackdown was produced, contested, sustained, and transformed in Hong Kong between 1989 and 2019. Drawing on data gathered through multiple sources such as news reports, digital media content, vigil onsite surveys, population surveys, and in-depth interviews with activists, rally participants, and other stakeholders, it identifies six key processes in the dynamics of social remembering: memory formation, memory mobilization, memory institutionalization, intergenerational transfer, memory repair, and memory balkanization. Memories of Tiananmen demonstrates how a socially dominant collective memory, even one the state finds politically irritable, can be generated and maintained through constant negotiation and efforts by a wide range of actors. While the book mainly focuses on the interplay between political changes and Tiananmen commemoration in the historical period within which the society enjoyed a significant degree of civil liberties, it also discusses how the trajectory of the collective memory may take a drastic turn as Hong Kong's autonomy is abridged. The book promises to be a key reference for anyone interested in collective memory studies, social movement research, political communication, and China and Hong Kong studies.

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Solid/liquid partition coefficients to model trace element critical loads for agricultural soils in Canada

Canadian Journal of Soil Science ◽

10.4141/s06-061 ◽

2007 ◽

Vol 87 (Special Issue) ◽

pp. 189-201 ◽

Cited By ~ 20

Author(s):

M I Sheppard ◽

S C Sheppard ◽

C A Grant

Keyword(s):

Trace Elements ◽

Trace Element ◽

Best Management Practices ◽

Management Practices ◽

Agricultural Land ◽

National Level ◽

Trace Element Content ◽

Crop Productivity ◽

Multiple Sources ◽

Solid Liquid

Canadian consumers are demanding a sustainable agricultural industry as well as products delivered under Best Management Practices (BMPs). Trace element accumulation in soils may influence crop productivity, food quality and ecosystem and human health. Canada’s feed and foodstuff export industry has already faced cases of penalties for high trace element content [cadmium (Cd) in durum wheat]. Thus, it is imperative to be able to estimate the accumulation and potential short- and long-term impacts of trace elements in soil. A national-level Trace Element Indicator (TEI) based on present loadings of trace elements to agricultural land is in progress. An Expert Panel including Canadian, American and Australian experts guided the assembly of a proposed methodology for this TEI. The proposed TEI, described briefly here, is a critical load approach with a single expression of the risk of impact from single or multiple trace elements from multiple sources (manures, biosolids, effluents and fertilizers and natural processes), invoked in a stochastic manner. Two key data requirements are the current background levels of trace elements in soil, and the leachability of these trace elements. A survey of total and soluble concentrations of 54 elements in up to 112 soils was completed. Although preliminary in scope, these represent key soil series in Canada. From this, a database of the solid/liquid partition coefficient, Kd, was computed. These Kd values will be used to characterize the leachability of the trace elements. Key words: Cadmium, copper, zinc, lead, nickel, uranium, metals, Kd, distribution coefficient

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Comparison and evaluation of statistical error models for scRNA-seq

10.1101/2021.07.07.451498 ◽

2021 ◽

Author(s):

Saket Choudhary ◽

Rahul Satija

Keyword(s):

Linear Models ◽

Negative Binomial ◽

Statistical Error ◽

Rna Seq ◽

Multiple Sources ◽

Error Models ◽

Wide Range ◽

Data Driven Approach ◽

Downstream Analysis ◽

Experimental Processing

Heterogeneity in single-cell RNA-seq (scRNA-seq) data is driven by multiple sources, including biological variation in cellular state as well as technical variation introduced during experimental processing. Deconvolving these effects is a key challenge for preprocessing workflows. Recent work has demonstrated the importance and utility of count models for scRNA-seq analysis, but there is a lack of consensus on which statistical distributions and parameter settings are appropriate. Here, we analyze 58 scRNA-seq datasets that span a wide range of technologies, systems, and sequencing depths in order to evaluate the performance of different error models. We find that while a Poisson error model appears appropriate for sparse datasets, we observe clear evidence of overdispersion for genes with sufficient sequencing depth in all biological systems, necessitating the use of a negative binomial model. Moreover, we find that the degree of overdispersion varies widely across datasets, systems, and gene abundances, and argues for a data-driven approach for parameter estimation. Based on these analyses, we provide a set of recommendations for modeling variation in scRNA-seq data, particularly when using generalized linear models or likelihood-based approaches for preprocessing and downstream analysis.

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Climate-dependent propagation of precipitation uncertainty into the water cycle

10.5194/hess-2019-660 ◽

2020 ◽

Author(s):

Ali Fallah ◽

Sungmin O ◽

Rene Orth

Keyword(s):

Hydrological Model ◽

Water Cycle ◽

State Of The Art ◽

Rain Gauge ◽

Multiple Sources ◽

Current State ◽

Wide Range ◽

The Impact ◽

Conceptual Hydrological Model

Abstract. Precipitation is a crucial variable for hydro-meteorological applications. Unfortunately, rain gauge measurements are sparse and unevenly distributed, which substantially hampers the use of in-situ precipitation data in many regions of the world. The increasing availability of high-resolution gridded precipitation products presents a valuable alternative, especially over gauge-sparse regions. Nevertheless, uncertainties and corresponding differences across products can limit the applicability of these data. This study examines the usefulness of current state-of-the-art precipitation datasets in hydrological modelling. For this purpose, we force a conceptual hydrological model with multiple precipitation datasets in > 200 European catchments. We consider a wide range of precipitation products, which are generated via (1) interpolation of gauge measurements (E-OBS and GPCC V.2018), (2) combination of multiple sources (MSWEP V2) and (3) data assimilation into reanalysis models (ERA-Interim, ERA5, and CFSR). For each catchment, runoff and evapotranspiration simulations are obtained by forcing the model with the various precipitation products. Evaluation is done at the monthly time scale during the period of 1984–2007. We find that simulated runoff values are highly dependent on the accuracy of precipitation inputs, and thus show significant differences between the simulations. By contrast, simulated evapotranspiration is generally much less influenced. The results are further analysed with respect to different hydro-climatic regimes. We find that the impact of precipitation uncertainty on simulated runoff increases towards wetter regions, while the opposite is observed in the case of evapotranspiration. Finally, we perform an indirect performance evaluation of the precipitation datasets by comparing the runoff simulations with streamflow observations. Thereby, E-OBS yields the best agreement, while furthermore ERA5, GPCC V.2018 and MSWEP V2 show good performance. In summary, our findings highlight a climate-dependent propagation of precipitation uncertainty through the water cycle; while runoff is strongly impacted in comparatively wet regions such as Central Europe, there are increasing implications on evapotranspiration towards drier regions.

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Multiple sources of signal amplification within the B cell Ras/MAPK pathway

10.1101/415737 ◽

2018 ◽

Author(s):

Justin D. Mclaurin ◽

Orion D. Weiner

Keyword(s):

Positive Feedback ◽

Signal Amplification ◽

Mapk Pathway ◽

Threshold Level ◽

Cell Types ◽

Multiple Sources ◽

Analog To Digital ◽

Ras Activation ◽

Wide Range ◽

Erk Activity

AbstractThe Ras-Map kinase (MAPK) cascade underlies functional decisions in a wide range of cell types and organisms. In B cells, positive feedback-driven Ras activation is the proposed source of the digital (all-or-none) MAPK responses following antigen stimulation. However, an inability to measure endogenous Ras activity in living cells has hampered our ability to test this model directly. Here we leverage biosensors of endogenous Ras and ERK activity to revisit this question. We find that BCR ligation drives switch-like Ras activation and that lower BCR signaling output is required for the maintenance versus the initiation of Ras activation. Surprisingly, digital ERK responses persist in the absence of positive feedback-mediated Ras activation, and digital ERK is observed at a threshold level of Ras activation. These data suggest an independent analog-to-digital switch downstream of Ras activation, and reveals that multiple sources of signal amplification exist within the Ras-ERK module of the BCR pathway.

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A Comprehensive Review of Minerals, Trace Elements, and Heavy Metals in Saffron

Current Pharmaceutical Biotechnology ◽

10.2174/1389201023666220104142531 ◽

2022 ◽

Vol 23 ◽

Author(s):

Sayyed Mohammad Ali Noori ◽

Mohammad Hashemi ◽

Sajjad Ghasemi

Keyword(s):

Heavy Metals ◽

Trace Elements ◽

Inductively Coupled Plasma ◽

Chemical Elements ◽

Absorption Spectrometry ◽

Atomic Emission ◽

Emission Spectrometry ◽

Inductively Coupled ◽

Wide Range ◽

The World

Abstract: Saffron is one of the most expensive spices in the world, and its popularity as a tasty food additive is spreading rapidly through many cultures and cuisines. Minerals and heavy metals are minor components found in saffron, which play a key role in the identification of the geographical origin, quality control, and food traceability, while they also affect human health. The chemical elements in saffron are measured using various analytical methods, such as techniques based on spectrometry or spectroscopy, including atomic emission spectrometry, atomic absorption spectrometry, inductively coupled plasma optical emission spectrometry, and inductively coupled plasma mass spectrometry. The present study aimed to review the published articles about heavy metals and minerals in saffron across the world. To date, 64 chemical elements have been found in different types of saffron, which could be divided into three groups of macro-elements, trace elements, and heavy metals (trace elements with a lower gravity/greater than five times that of water and other inorganic sources). Furthermore, the chemical elements in the saffron samples of different countries have a wide range of concentrations. These differences may be affected by geographical condition such as physicochemical properties of the soil, weather and other environmental conditions like saffron cultivation and its genotype.

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Supplementing Substance Use Prevention With Sexual Health Education: A Partner-Informed Approach to Intervention Development

Health Promotion Practice ◽

10.1177/1524839920947683 ◽

2020 ◽

pp. 152483992094768

Author(s):

Terrinieka W. Powell ◽

Meghan Jo ◽

Anne D. Smith ◽

Beth D. Marshall ◽

Santha Thigpen ◽

...

Keyword(s):

Substance Use ◽

Health Education ◽

Sexual Health ◽

Intervention Development ◽

Lessons Learned ◽

Evidence Based ◽

Substance Use Prevention ◽

Sexual Health Education ◽

Multiple Sources ◽

Wide Range

Supplementing substance use prevention with sexual health education would allow educators to address the risk and protective factors that influence both health issues. This streamlined approach may minimize the inefficiencies of multisession, single-purpose interventions. Our team developed a supplemental sexual and reproductive health (SRH) unit to align with an existing evidence-based intervention, LifeSkills Training (LST). This goal of this article is to describe our process, final product, lessons learned, and future directions. Our partner-informed approach took place across three key phases: (1) formative insights, (2) unit development, and (3) pilot implementation. The final supplemental SRH unit is ten, 45-minute sessions offered to seventh- and eighth-grade students and includes a set of learning objectives that are aligned with individual sessions. The supplemental SRH unit also mirrors existing LST modules in length, flow, layout, facilitator instructions, focus on prevention, and utilization of a student workbook. Lessons learned include strategies to effectively incorporate a wide range of ongoing feedback from multiple sources and quickly respond to staff turnover. This partnership approach serves as a model for researchers and practitioners aiming to extend the reach of existing evidence-based programs.

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Multivariate Statistical Analysis of Trace Elements in Pyrite: Prediction, Bias and Artefacts in Defining Mineral Signatures

Minerals ◽

10.3390/min10010061 ◽

2020 ◽

Vol 10 (1) ◽

pp. 61 ◽

Cited By ~ 3

Author(s):

Marija Dmitrijeva ◽

Nigel J. Cook ◽

Kathy Ehrig ◽

Cristiana L. Ciobanu ◽

Andrew V. Metcalfe ◽

...

Keyword(s):

Trace Elements ◽

Statistical Analysis ◽

Trace Element ◽

South Australia ◽

Large Datasets ◽

Ore Deposits ◽

Partial Replacement ◽

Multivariate Statistical ◽

Wide Range ◽

Olympic Dam

Pyrite is the most common sulphide in a wide range of ore deposits and well known to host numerous trace elements, with implications for recovery of valuable metals and for generation of clean concentrates. Trace element signatures of pyrite are also widely used to understand ore-forming processes. Pyrite is an important component of the Olympic Dam Cu–U–Au–Ag orebody, South Australia. Using a multivariate statistical approach applied to a large trace element dataset derived from analysis of random pyrite grains, trace element signatures in Olympic Dam pyrite are assessed. Pyrite is characterised by: (i) a Ag–Bi–Pb signature predicting inclusions of tellurides (as PC1); and (ii) highly variable Co–Ni ratios likely representing an oscillatory zonation pattern in pyrite (as PC2). Pyrite is a major host for As, Co and probably also Ni. These three elements do not correlate well at the grain-scale, indicating high variability in zonation patterns. Arsenic is not, however, a good predictor for invisible Au at Olympic Dam. Most pyrites contain only negligible Au, suggesting that invisible gold in pyrite is not commonplace within the deposit. A minority of pyrite grains analysed do, however, contain Au which correlates with Ag, Bi and Te. The results are interpreted to reflect not only primary patterns but also the effects of multi-stage overprinting, including cycles of partial replacement and recrystallisation. The latter may have caused element release from the pyrite lattice and entrapment as mineral inclusions, as widely observed for other ore and gangue minerals within the deposit. Results also show the critical impact on predictive interpretations made from statistical analysis of large datasets containing a large percentage of left-censored values (i.e., those falling below the minimum limits of detection). The treatment of such values in large datasets is critical as the number of these values impacts on the cluster results. Trimming of datasets to eliminate artefacts introduced by left-censored data should be performed with caution lest bias be unintentionally introduced. The practice may, however, reveal meaningful correlations that might be diluted using the complete dataset.

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