Kinetically driven successive sodic and potassic alteration of feldspar

AbstractThe dynamic evolutions of fluid-mineral systems driving large-scale geochemical transformations in the Earth’s crust remain poorly understood. We observed experimentally that successive sodic and potassic alterations of feldspar can occur via a single self-evolved, originally Na-only, hydrothermal fluid. At 600 °C, 2 kbar, sanidine ((K,Na)AlSi3O8) reacted rapidly with a NaCl fluid to form albite (NaAlSi3O8); over time, some of this albite was replaced by K-feldspar (KAlSi3O8), in contrast to predictions from equilibrium reaction modelling. Fluorine accelerated the process, resulting in near-complete back-replacement of albite within 1 day. These findings reveal that potassic alteration can be triggered by Na-rich fluids, indicating that pervasive sequential sodic and potassic alterations associated with mineralization in some of the world’s largest ore deposits may not necessarily reflect externally-driven changes in fluid alkali contents. Here, we show that these reactions are promoted at the micro-scale by a self-evolving, kinetically-driven process; such positive feedbacks between equilibrium and kinetic factors may be essential in driving pervasive mineral transformations.

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Dynamic feldspar alteration governed by single self-evolved fluid system

10.21203/rs.3.rs-61362/v1 ◽

2020 ◽

Author(s):

Gan Duan ◽

Joel Brugger ◽

Rahul Ram ◽

Yan Xing ◽

Barbara Etschmann

Keyword(s):

Hydrothermal Fluid ◽

Large Scale ◽

Reaction System ◽

Ore Deposits ◽

Fluid Mixing ◽

Fluid System ◽

Mineral Reaction ◽

Hydrothermal Processes ◽

Copper Gold ◽

Mineral Interfaces

Abstract The evolution of hydrothermal fluids during metasomatic and/or hydrothermal processes is responsible for the formation of ore deposits and associated alteration. In systems with well-developed breccia and fractures, mineral reactions are largely driven by decompression boiling, fluid cooling or external fluid mixing, but in less permeable rocks, elements exchanges occur at fluid-mineral interfaces, resulting in a self-evolved fluid-mineral reaction system. However, the dynamic fluid evolution leading to large-scale (km) alteration remains poorly understood. We observed experimentally that the sequential sodic and potassic alterations associated with mineralization in large ore deposits, in particular Iron Oxide Copper Gold (IOCG) deposits, can occur via a single self-evolved, originally Na-only, hydrothermal fluid, driven by a positive feedback between equilibrium and kinetic factors. Albite formed first upon reaction of sanidine ((K,Na)AlSi3O8) with a NaCl fluid at 600˚C, 2 kbar. However, with increasing reaction time, some of the initially formed albite was in-turn replaced by K-feldspar (KAlSi3O8). Fluorine accelerated the process, resulting in nearly complete back-replacement of albite within 1 day. These experiments demonstrate that potassic alteration can be induced by Na-rich fluids, and pervasive sequential sodic and potassic alterations do not necessarily reflect near-equilibrium, externally-driven changes in fluid alkali contents.

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Analysis of 220 Years of Floodplain Population Dynamics in the US at Different Spatial Scales

Water ◽

10.3390/w13020141 ◽

2021 ◽

Vol 13 (2) ◽

pp. 141

Author(s):

Firoza Akhter ◽

Maurizio Mazzoleni ◽

Luigia Brandimarte

Keyword(s):

Population Dynamics ◽

Large Scale ◽

Spatial Scales ◽

National Level ◽

State Level ◽

Economic Activities ◽

Protection Measures ◽

Management Planning ◽

The Us ◽

Over Time

In this study, we explore the long-term trends of floodplain population dynamics at different spatial scales in the contiguous United States (U.S.). We exploit different types of datasets from 1790–2010—i.e., decadal spatial distribution for the population density in the US, global floodplains dataset, large-scale data of flood occurrence and damage, and structural and nonstructural flood protection measures for the US. At the national level, we found that the population initially settled down within the floodplains and then spread across its territory over time. At the state level, we observed that flood damages and national protection measures might have contributed to a learning effect, which in turn, shaped the floodplain population dynamics over time. Finally, at the county level, other socio-economic factors such as local flood insurances, economic activities, and socio-political context may predominantly influence the dynamics. Our study shows that different influencing factors affect floodplain population dynamics at different spatial scales. These facts are crucial for a reliable development and implementation of flood risk management planning.

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China’s Investments in Germany and the Impact of the COVID-19 Pandemic

Intereconomics ◽

10.1007/s10272-021-0962-0 ◽

2021 ◽

Vol 56 (2) ◽

pp. 113-119

Author(s):

Xinming Xia ◽

Wan-Hsin Liu

Keyword(s):

Large Scale ◽

Know How ◽

Advanced Technologies ◽

The Future ◽

Potential Impact ◽

Chinese State ◽

The Impact ◽

Gain Access ◽

Over Time

AbstractThis paper analyses how China’s investments in Germany have developed over time and the potential impact of the COVID-19 pandemic in this regard, based on four different datasets, including our own survey in mid-2020. Our analysis shows that Germany is currently one of the most attractive investment destinations for Chinese investors. Chinese state-owned enterprises have played an important role as investors in Germany — particularly in large-scale projects. The COVID-19 pandemic has had some negative but rather temporary effects on Chinese investments in Germany. Germany is expected to stay attractive to Chinese investors who seek to gain access to advanced technologies and know-how in the future.

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Pioneers in International Administration: A Prosopography of the Directors of the League of Nations Secretariat

New Global Studies ◽

10.1515/ngs-2018-0039 ◽

2019 ◽

Vol 13 (2) ◽

pp. 190-227 ◽

Cited By ~ 1

Author(s):

Torsten Kahlert

Keyword(s):

International Organizations ◽

Large Scale ◽

Second World War ◽

League Of Nations ◽

World War ◽

Clear Trend ◽

Organizational Contexts ◽

Career Trajectories ◽

Second World ◽

Over Time

AbstractThis article investigates interwar internationalism from the perspective of the highest personnel of the first large-scale international administration, the League of Nations Secretariat. It applies a prosopographical approach in order to map out the development of the composition of the group of the section directors of the Secretariat over time in terms of its social and cultural characteristics and career trajectories. The analysis of gender, age, nationality, as well as educational and professional backgrounds and careers after their service for the League’s Secretariat gives insight on how this group changed over time and what it tells us about interwar internationalism. I have three key findings to offer in this article: First, the Secretariat was far from being a static organization. On the contrary, the Secretariat’s directors developed in three generations each with distinct characteristics. Second, my analysis demonstrates a clear trend towards professionalization and growing maturity of the administration over time. Third, the careers of the directors show a clear pattern of continuity across the Second World War and beyond. Even though the careers continued in different organizational contexts, the majority of the directors remained closely connected to the world of internationalism of the League, the UN world and its surrounding organizations. On a methodological level, the article offers an example of how prosopographical analysis can be used to study international organizations.

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A Framework and Case Study for Earthquake Vulnerability Assessment of Incrementally Expanding Buildings

Earthquake Spectra ◽

10.1193/011116eqs010m ◽

2017 ◽

Vol 33 (4) ◽

pp. 1369-1384 ◽

Cited By ~ 4

Author(s):

David Lallemant ◽

Henry Burton ◽

Luis Ceferino ◽

Zach Bullock ◽

Anne Kiremidjian

Keyword(s):

Large Scale ◽

Building Construction ◽

Risk Assessment Models ◽

Earthquake Vulnerability ◽

Valley Area ◽

Common Understanding ◽

Dynamic Structural Analysis ◽

Neighborhood Level ◽

Over Time

This study proposes a framework for incorporating time-dependent fragility into large-scale risk assessment models, focusing on incremental building expansion as a significant driver of changes in vulnerability. In rapidly urbanizing areas in developing countries, the pay-as-you-go process of informal building construction and staged expansion is the de facto pattern of growth. While there is a common understanding that such expansions increase the earthquake vulnerability of buildings, this study proposes a framework to model and quantify this increase. Vulnerability curves are developed through incremental dynamic structural analysis for common building expansion typologies. Building expansions are modeled as Markov chain processes and used to simulate stochastic expansion sequences over a building's lifetime. The model is then used to simulate a hypothetical neighborhood in the Kathmandu valley area to understand neighborhood-level risk over time. The study provides a new methodology to analyze changing seismic risk over time, driven by any building modification that impacts the building's vulnerability (incremental expansion, deterioration, retrofit, etc.).

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Rapid Spread of the SARS-CoV-2 Variant of Concern 202012/01 in Southern Italy (December 2020–March 2021)

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18094766 ◽

2021 ◽

Vol 18 (9) ◽

pp. 4766

Author(s):

Daniela Loconsole ◽

Francesca Centrone ◽

Caterina Morcavallo ◽

Silvia Campanella ◽

Anna Sallustio ◽

...

Keyword(s):

Clinical Characteristics ◽

Large Scale ◽

Southern Italy ◽

Whole Genome ◽

Third Wave ◽

Gene Target ◽

The Third ◽

Rapid Spread ◽

Pharmaceutical Interventions ◽

Over Time

Epidemiological and virological studies have revealed that SARS-CoV-2 variants of concern (VOCs) are emerging globally, including in Europe. The aim of this study was to evaluate the spread of B.1.1.7-lineage SARS-CoV-2 in southern Italy from December 2020–March 2021 through the detection of the S gene target failure (SGTF), which could be considered a robust proxy of VOC B.1.1.7. SGTF was assessed on 3075 samples from week 52/2020 to week 10/2021. A subset of positive samples identified in the Apulia region during the study period was subjected to whole-genome sequencing (WGS). A descriptive and statistical analysis of the demographic and clinical characteristics of cases according to SGTF status was performed. Overall, 20.2% of samples showed SGTF; 155 strains were confirmed as VOC 202012/01 by WGS. The proportion of SGTF-positive samples rapidly increased over time, reaching 69.2% in week 10/2021. SGTF-positive cases were more likely to be symptomatic and to result in hospitalization (p < 0.0001). Despite the implementation of large-scale non-pharmaceutical interventions (NPIs), such as the closure of schools and local lockdowns, a rapid spread of VOC 202012/01 was observed in southern Italy. Strengthened NPIs and rapid vaccine deployment, first among priority groups and then among the general population, are crucial both to contain the spread of VOC 202012/01 and to flatten the curve of the third wave.

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Ocean deoxygenation, the global phosphorus cycle and the possibility of human-caused large-scale ocean anoxia

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2016.0318 ◽

2017 ◽

Vol 375 (2102) ◽

pp. 20160318 ◽

Cited By ~ 20

Author(s):

Andrew J. Watson ◽

Timothy M. Lenton ◽

Benjamin J. W. Mills

Keyword(s):

Chemical Weathering ◽

Large Scale ◽

Oxygen Demand ◽

Subsurface Water ◽

Phosphorus Cycle ◽

Low Oxygen ◽

Positive Feedbacks ◽

Future Possibility ◽

Warming World ◽

Ocean Deoxygenation

The major biogeochemical cycles that keep the present-day Earth habitable are linked by a network of feedbacks, which has led to a broadly stable chemical composition of the oceans and atmosphere over hundreds of millions of years. This includes the processes that control both the atmospheric and oceanic concentrations of oxygen. However, one notable exception to the generally well-behaved dynamics of this system is the propensity for episodes of ocean anoxia to occur and to persist for 10 5 –10 6 years, these ocean anoxic events (OAEs) being particularly associated with warm ‘greenhouse’ climates. A powerful mechanism responsible for past OAEs was an increase in phosphorus supply to the oceans, leading to higher ocean productivity and oxygen demand in subsurface water. This can be amplified by positive feedbacks on the nutrient content of the ocean, with low oxygen promoting further release of phosphorus from ocean sediments, leading to a potentially self-sustaining condition of deoxygenation. We use a simple model for phosphorus in the ocean to explore this feedback, and to evaluate the potential for humans to bring on global-scale anoxia by enhancing P supply to the oceans. While this is not an immediate global change concern, it is a future possibility on millennial and longer time scales, when considering both phosphate rock mining and increased chemical weathering due to climate change. Ocean deoxygenation, once begun, may be self-sustaining and eventually could result in long-lasting and unpleasant consequences for the Earth's biosphere. This article is part of the themed issue ‘Ocean ventilation and deoxygenation in a warming world’.

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Disparity and Dynamics of Social Distancing Behaviors in Japan: An Investigation of mobile phone mobility data (Preprint)

10.2196/preprints.31557 ◽

2021 ◽

Author(s):

Zeyu Lyu ◽

Hiroki Takikawa

Keyword(s):

Large Scale ◽

Age Groups ◽

Mitigation Strategies ◽

Social Distancing ◽

Demographic Groups ◽

Fine Grained ◽

Mobility Data ◽

The Social ◽

The Government ◽

Over Time

BACKGROUND The availability of large-scale and fine-grained aggregated mobility data has allowed researchers to observe the dynamic of social distancing behaviors at high spatial and temporal resolutions. Despite the increasing attentions paid to this research agenda, limited studies have focused on the demographic factors related to mobility and the dynamics of social distancing behaviors has not been fully investigated. OBJECTIVE This study aims to assist in the design and implementation of public health policies by exploring the social distancing behaviors among various demographic groups over time. METHODS We combined several data sources, including mobile tracking data and geographical statistics, to estimate visiting population of entertainment venues across demographic groups, which can be considered as the proxy of social distancing behaviors. Then, we employed time series analyze methods to investigate how voluntary and policy-induced social distancing behaviors shift over time across demographic groups. RESULTS Our findings demonstrate distinct patterns of social distancing behaviors and their dynamics across age groups. The population in the entertainment venues comprised mainly of individuals aged 20–40 years, while according to the dynamics of the mobility index and the policy-induced behavior, among the age groups, the extent of reduction of the frequency of visiting entertainment venues during the pandemic was generally the highest among younger individuals. Also, our results indicate the importance of implementing the social distancing policy promptly to limit the spread of the COVID-19 infection. However, it should be noticed that although the policy intervention during the second wave in Japan appeared to increase the awareness of the severity of the pandemic and concerns regarding COVID-19, its direct impact has been largely decreased could only last for a short time. CONCLUSIONS At the time we wrote this paper, in Japan, the number of daily confirmed cases was continuously increasing. Thus, this study provides a timely reference for decision makers about the current situation of policy-induced compliance behaviors. On the one hand, age-dependent disparity requires target mitigation strategies to increase the intention of elderly individuals to adopt mobility restriction behaviors. On the other hand, considering the decreasing impact of self-restriction recommendations, the government should employ policy interventions that limit the resurgence of cases, especially by imposing stronger, stricter social distancing interventions, as they are necessary to promote social distancing behaviors and mitigate the transmission of COVID-19. CLINICALTRIAL None

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Temporal Activity Path Based Character Correction in Heterogeneous Social Networks via Multimedia Sources

Advances in Multimedia ◽

10.1155/2018/2058670 ◽

2018 ◽

Vol 2018 ◽

pp. 1-16

Author(s):

Jun Long ◽

Lei Zhu ◽

Zhan Yang ◽

Chengyuan Zhang ◽

Xinpan Yuan

Keyword(s):

Social Networks ◽

Social Network ◽

Large Scale ◽

Multimedia Data ◽

Attribute Information ◽

Novel Method ◽

Relationship Network ◽

Heterogeneous Social Networks ◽

The Relationship ◽

Over Time

Vast amount of multimedia data contains massive and multifarious social information which is used to construct large-scale social networks. In a complex social network, a character should be ideally denoted by one and only one vertex. However, it is pervasive that a character is denoted by two or more vertices with different names; thus it is usually considered as multiple, different characters. This problem causes incorrectness of results in network analysis and mining. The factual challenge is that character uniqueness is hard to correctly confirm due to lots of complicated factors, for example, name changing and anonymization, leading to character duplication. Early, limited research has shown that previous methods depended overly upon supplementary attribute information from databases. In this paper, we propose a novel method to merge the character vertices which refer to the same entity but are denoted with different names. With this method, we firstly build the relationship network among characters based on records of social activities participating, which are extracted from multimedia sources. Then we define temporal activity paths (TAPs) for each character over time. After that, we measure similarity of the TAPs for any two characters. If the similarity is high enough, the two vertices should be considered as the same character. Based on TAPs, we can determine whether to merge the two character vertices. Our experiments showed that this solution can accurately confirm character uniqueness in large-scale social network.

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Evidence Graphs: Supporting Transparent and FAIR Computation, with Defeasible Reasoning on Data, Methods and Results

10.1101/2021.03.29.437561 ◽

2021 ◽

Author(s):

Sadnan Al Manir ◽

Justin Niestroy ◽

Maxwell Adam Levinson ◽

Timothy Clark

Keyword(s):

Time Series ◽

Large Scale ◽

Time Series Data ◽

Predictive Analytics ◽

Defeasible Reasoning ◽

Series Data ◽

Inference Rules ◽

Deep Networks ◽

Evidence Graph ◽

Over Time

Introduction: Transparency of computation is a requirement for assessing the validity of computed results and research claims based upon them; and it is essential for access to, assessment, and reuse of computational components. These components may be subject to methodological or other challenges over time. While reference to archived software and/or data is increasingly common in publications, a single machine-interpretable, integrative representation of how results were derived, that supports defeasible reasoning, has been absent. Methods: We developed the Evidence Graph Ontology, EVI, in OWL 2, with a set of inference rules, to provide deep representations of supporting and challenging evidence for computations, services, software, data, and results, across arbitrarily deep networks of computations, in connected or fully distinct processes. EVI integrates FAIR practices on data and software, with important concepts from provenance models, and argumentation theory. It extends PROV for additional expressiveness, with support for defeasible reasoning. EVI treats any com- putational result or component of evidence as a defeasible assertion, supported by a DAG of the computations, software, data, and agents that produced it. Results: We have successfully deployed EVI for very-large-scale predictive analytics on clinical time-series data. Every result may reference its own evidence graph as metadata, which can be extended when subsequent computations are executed. Discussion: Evidence graphs support transparency and defeasible reasoning on results. They are first-class computational objects, and reference the datasets and software from which they are derived. They support fully transparent computation, with challenge and support propagation. The EVI approach may be extended to include instruments, animal models, and critical experimental reagents.

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