bluuebunny/crossref_metadata_2025 huggingface dataset:
Soils from an iron and steel scrap storage yard remediated with aided phytostabilization
Authors: Radziemska Maja , Koda Eugeniusz , Vaverkovà Magdalena D. , Gusiatin Zygmunt M. , Cerdà Artemi , Brtnický Martin , Mazur Zbigniew
Published: November 2018

Areas degraded by industrial activity demonstrate unfavorable chemical and physical conditions, including a high concentration of trace elements (TEs), which reduce the growth and development of appropriate plant cover. For the above reasons, in recent years, the demand for the development of natural and effective technologies for removing particularly hazardous compounds such as TEs from the environment has been growing. Because aided phytostabilization is a relatively new technology, examination of new additions immobilizing TEs in combination with an appropriately selected species plan poses a challenge in environmental protection and engineering. The novelty of this study is in the assessment of the usefulness of previously not applied soil amendments in processes of TEs immobilization in contaminated soils. This study presents the results of a vegetation experiment using a mix of grasses and rarely used mineral soil amendments (halloysite, diatomite, dolomite) for aided phytostabilization of soil originating from an area affected by industrial activity and characterized by high TEs concentrations. Additionally, the degree of phytotoxicity of the examined soils was determined. The greatest above‐ground biomass was observed when diatomite, dolomite, and halloysite were added to the soil. The concentrations of the analyzed TEs in test plants were higher in roots than in the above‐ground parts. This indicates that mineral amendments affected soil properties promoting TEs precipitation and decreasing TEs bioavailability. The highest increase in soil pH was observed after the application of dolomite to the soil. The average contents of Pb, Ni, Cu, and Cr in soil demonstrated the highest reduction after diatomite and halloysite application. The conducted research confirms the possibility of applying the examined soil additives to support phytostabilization of alkaline soil highly contaminated with TEs.
A significant increase in the normalized difference vegetation index during the rapid economic development in the Pearl River Delta of China
Authors: Hu Mengmeng , Xia Beicheng
Published: November 2018

Since 2000, the gross domestic product (GDP) of the Pearl River Delta (PRD) has increased by more than eight‐fold. Experiences throughout the world indicate that the impacts of economic development on vegetation are particularly important. This study analyzed the variations in vegetation coverage in the PRD from 2000 to 2016. Moderate resolution imaging spectroradiometer normalized difference vegetation index (NDVI) data were employed, whereas climate data, GDP, and population were also used as influencing factors. Topographic factors were introduced to explain the spatial vegetation patterns, and the impacts of human activities on vegetation were explored. The results revealed (a) the overall vegetation coverage in the PRD showed an increasing trend, and the overall average NDVI increased by 0.0033/a. (b) The spatial pattern did not change greatly, but the high and low NDVI values moved to low elevations and shallow topographic slopes where human activities were prevalent. This trend resulted in increased NDVI values in 38% of the area of the PRD (p < 0.01). (c) There was a positive correlation between NDVI and economic growth (GDP, population), with correlation coefficients greater than 0.8 (p < 0.01). NDVI is influenced by climate change and human activities (such as afforestation, resident lifestyles, and economic development policies). This study reveals that with good policies, both rapid economic development and vegetation coverage improvements can be simultaneously achieved in a region. The findings of this study are crucial for the sustainable development of the mega‐urban agglomerations of the PRD and Guangdong‐Hong Kong‐Macau Grand Bay.
PTRHD1 Loss‐of‐function mutation in an african family with juvenile‐onset Parkinsonism and intellectual disability
Authors: Kuipers Demy J.S. , Carr Jonathan , Bardien Soraya , Thomas Pearl , Sebate Boiketlo , Breedveld Guido J. , van Minkelen Rick , Brouwer Rutger W.W. , van Ijcken Wilfred F.J. , van Slegtenhorst Marjon A. , Bonifati Vincenzo , Quadri Marialuisa
Published: November 2018

Background: The genetic bases of PD in sub‐Saharan African (SSA) populations remain poorly characterized, and analysis of SSA families with PD might lead to the discovery of novel disease‐related genes.

Objectives: To investigate the clinical features and identify the disease‐causing gene in a black South African family with 3 members affected by juvenile‐onset parkinsonism and intellectual disability.

Methods: Clinical evaluation, neuroimaging studies, whole‐exome sequencing, homozygosity mapping, two‐point linkage analysis, and Sanger sequencing of candidate variants.

Result: A homozygous 28‐nucleotide frameshift deletion in the PTRHD1 coding region was identified in the 3 affected family members and linked to the disease with genome‐wide significant evidence. PTRHD1 was recently nominated as the disease‐causing gene in two Iranian families, each containing 2 siblings with similar phenotypes and homozygous missense mutations.

Conclusion: Together with the previous reports, we provide conclusive evidence that loss‐of‐function mutations in PTRHD1 cause autosomal‐recessive juvenile parkinsonism and intellectual disability. © 2018 International Parkinson and Movement Disorder Society
Effects of variable viscosity on pulsatile flow of blood in a tapered stenotic flexible artery
Authors: Mukhopadhyay Subrata , Mandal Mani Shankar , Mukhopadhyay Swati
Published: November 2018

The objective of the present study is to investigate the effects of variable viscosity on incompressible laminar pulsatile flow of blood through an overlapping doubly constricted tapered artery. To mimic the realistic situation, wall of the artery is taken to be flexible, and physiologically relevant pulsatile flow is introduced. The governing equations of blood flow are made dimensionless. A coordinate transformation is used to make the overlapping doubly constricted wall geometry of tube to a straight tube. Taking advantage of the Stream function–Vorticity formulation, the system of partial differential equations is then solved numerically by finite difference approximations. Effects of Reynolds number, Strouhal number, degree of contraction, tapering angle, and viscosity parameters are presented graphically and analyzed. The results show that formation of stenosis and tapering disturb the flow field significantly, and degree of stenosis is more important in influencing blood flow compared with tapering.
Fractional supersymmetric su(2) algebras
Authors: Uçan Yasemen
Published: November 2018

In this paper, the third root of the Lie algebra su(2) based on the permutation group S3 is formulated in the Hopf algebra formalism.
Analysis of lateral loading of pile groups using embedded beam elements with interaction surface
Authors: Turello Diego F. , Pinto Federico , Sánchez Pablo J.
Published: November 2018

The numerical simulation of soil‐pile interaction problems, by means of full 3D finite element models, involves a large number of degrees of freedom (DOF) and difficulties during the mesh generation process. In order to reduce the unknowns and simplify and properly analyze such class of geotechnical problems, the so‐called embedded beam elements (EBE) have recently been developed. In a preceding contribution of the authors, an improved EBE formulation, which brings into play the soil‐pile interaction surface, was proposed with the aim to localize material plasticity in the soil surrounding the pile. This embedded beam model couples two different finite elements, each described by distinct kinematics (ie, solid and beam). The coupling is incorporated in the formulation by means of kinematical constrains established over the solid and beam displacement fields on the interaction surface. One of the main advantages of the embedded elements is that the addition of beams structural members immersed within the 3D soil model does not represent a constraint for the solid mesh, which can be adopted independently from the beam mesh. In this paper, the lateral loading of pile groups is studied by means of the proposed EBE approach with elasto‐plastic interfaces. In order to represent a rigid cap, a master node and a special set of kinematical restrictions are incorporated into the formulation. The paper presents results obtained by means of the present formulation compared against other well‐established analysis methods and test results published in the literature, for both elastic and elasto‐plastic cases.
PbSe Quantum Dot Passivated Via Mixed Halide Perovskite Nanocrystals for Solar Cells With Over 9% Efficiency
Authors: Hu Long , Zhang Zhilong , Patterson Robert J. , Shivarudraiah Sunil B. , Zhou Zhicong , Ng Michael , Huang Shujuang , Halpert Jonathan E.
Published: November 2018

PbSe quantum dots (QDs) have stronger electronic coupling resulting from a large Bohr exciton radius, suggesting PbSe QDs may be able to achieve superior charge separation and transport in optoelectronic devices compared with PbS QDs. However, PbS QDs solar cell have achieved a certified 12.01% power conversion efficiency (PCE), whereas PbSe QD photovoltaics lag behind at 8.2% PCE. One reason for this difference is that there has been significantly less work done on surface passivation of PbSe QDs. Here, the surface passivation of chlorinated PbSe QDs is optimized via a halide ion exchange treatment using mixed halide CsPb(Br/I)3 perovskite nanocrystals. Champion devices made from treated QDs achieved a PCE of 9.2%, Voc of 0.56 V, Jsc of 25.7 mA cm−2, and fill factor of 64%. Average PCEs for optimized cells are 8.9%. Detailed physical characterizations including capacitance‐voltage (C‐V), Voc, and Jsc as a function of light intensity, transient photovoltage, and photocurrent measurements are all carried out to investigate the mechanism of the improvement in the PCE and to understand the role of the mixed halide perovskites in providing superior surface passivation for PbSe solar cells. At this time, 9.2% is the highest PCE yet reported for PbSe QDs solar cells.
Improving the Electron Mobility of ITIC by End‐Group Modulation: The Role of Fluorination and π‐Extension
Authors: Han Guangchao , Guo Yuan , Ning Lu , Yi Yuanping
Published: November 2018

Nonfullerene organic solar cells (OSCs) using ITIC derivatives as electron acceptors have achieved power conversion efficiencies up to 14%, yet optimal active‐layer thicknesses are still limited to ≈100 nm, ascribed mainly to the low electron mobilities (≈10−4 cm2/Vs) of these acceptors. Because of the large steric hindrance of the bulky side chains on the fused‐ring core, ITIC favors a local π–π stacking between the electron‐withdrawing end groups (IC), which provides the main electron transport channel across the bulk volume. Here, the influence of different fluoro‐substituted and π‐extended (i.e., benzene‐fused) positions in the phenyl moiety of IC on the electron transport properties is systematically investigated by multiscale theoretical simulations. It is found that the electron mobility can be remarkablely improved by proper fluorination and π‐extension, especially by π‐extension, due to the lower reorganization energy and stronger end‐group π‐π interaction. Moreover, a judicious combination of π‐extension and fluorination can lead to a nearly six‐fold increase of the electron mobility with respect to ITIC. This work shows that the electron mobility of A‐D‐A nonfullerene acceptors can be effectively improved by end‐group engineering, paving the way toward higher‐performance organic solar cells.
Massive Anti-de Sitter gravity from string theory
Authors: Bachas Constantin , Lavdas Ioannis
Published: November 2018

Abstract

We study top-down embeddings of massive Anti-de Sitter (AdS) gravity in type-IIB string theory. The supergravity solutions have a AdS4 fiber warped over a manifold M6 whose shape resembles that of scottish bagpipes: the ‘bag’ is a conventional AdS4 compactification manifold, while the ‘pipes’ are highly-curved semi-infinite Janus throats. Besides streamlining previous discussions of the problem, our main new result is a formula for the graviton mass which only depends on the effective gravitational coupling of the bag, and on the D3-brane charges and dilaton jumps of the Janus throats. We compare these embeddings to the Karch-Randall model and to other bottom-up proposals for massive AdS gravity, and we comment on their holographic interpretation. This is a companion paper to [1], where some closely-related bimetric models with pure AdS5×S5 throats were analyzed.
Low-energy effects of Lepton Flavour Universality Violation
Authors: Cornella Claudia , Feruglio Ferruccio , Paradisi Paride
Published: November 2018

Abstract

The persisting anomalous data in semileptonic B-decays point towards New Physics models exhibiting large sources of Lepton Flavour Universality Violation. In this work we generalise previous studies by considering frameworks which include an enlarged set of semileptonic four-fermion operators invariant under the SM gauge group, with New Physics affecting mainly the third generation. We derive the low-energy effective Lagrangian including the leading electroweak corrections, mandatory to obtain reliable predictions. As a particularly interesting case, we analyse the scenario where the dominant New Physics effects are encoded in the Wilson coefficient C
9, as favoured by global fit analyses of b → s data. We find that also in this case the stringent experimental bounds on Z-pole observables and τ decays challenge a simultaneous explanation of charged and neutral-current non-standard data.
Resilience Among Police Officers: a Critical Systematic Review of Used Concepts, Measures, and Predictive Values of Resilience
Authors: Janssens Kim M. E. , van der Velden Peter G. , Taris Ruben , van Veldhoven Marc J. P. M.
Published: November 2018

Resilience, hardiness, and psychological capital are considered to be important capacities for police officers to cope with and adapt to challenging stressful and potentially traumatic situations. Despite their growing popularity, a systematic review assessing used concepts and instruments for these capacities and synthesizing the results of studies on the predictive values of resilience, hardiness, and psychological capital among police officers is absent. The aim of the present study is to fill this gap of scientific knowledge, and for this purpose, a systematic literature search was conducted using PsycInfo, Pubmed, and Web of Science. We identified 17 cross-sectional and 5 longitudinal studies. Results showed that resilience, hardiness, and psychological capital were studied mostly in relation to physical and mental health variables. No study focused on officers’ professional functioning. In both cross-sectional and longitudinal studies, associations with health variables were very weak to moderate, while cross-sectional studies mostly yielded stronger associations than longitudinal associations. In sum, we found no empirical support for the growing popularity.
Evidence-based review of methods used to reduce pain after excisional hemorrhoidectomy
Authors: Emile Sameh Hany
Published: November 2018

Background Excisional hemorrhoidectomy is one of the most commonly performed anorectal procedures. Despite the satisfactory outcomes of excisional hemorrhoidectomy, the pain perceived by the patients following the procedure can be a distressing sequel. This review aimed to search the current literature for the existing evidence on how to avoid or minimize the severity of post-hemorrhoidectomy pain.

Methods An organized literature search was performed using electronic databases including PubMed/Medline and Google Scholar service for the articles that evaluated different methods for pain relief after excisional hemorrhoidectomy. Then, the studies were summarized in a narrative way illustrating the hypothesis and the outcomes of each study. The methods devised to reduce pain after excisional hemorrhoidectomy were classified into three main categories: technical tips; systemic and topical agents; and surgical methods. The efficacy of each method was highlighted along the level of evidence supporting it.

Results Stronger evidence (level Ia) supported LigaSure hemorrhoidectomy and the use of glyceryl trinitrate ointment to be associated with significant pain relief after excisional hemorrhoidectomy whereas the remaining methods were supported by lower level of evidence (level Ib).

Conclusion The use of LigaSure in performing excisional hemorrhoidectomy and the application of topical glyceryl trinitrate ointment contributed to remarkable relief of postoperative pain after excisional hemorrhoidectomy according to the highest level of evidence. Perhaps a multimodality strategy that combines systemic and topical agents can be the optimal method for control of pain after excisional hemorrhoidectomy, yet further prospective trials are required to draw such conclusion.
FST sealing technology plays pivotal role in enhancing hydraulic accumulators
Authors: Atkinson Simon
Published: November 2018

Hydraulic accumulators provide improved energy efficiency by enabling manufacturers to install smaller hydraulic systems to actuate transmission gears. This technology focus article briefly describes how Freudenberg Sealing Technologies' (FST) hydraulic accumulator systems make use of the company's sealing technology to help save energy and ease installation challenges in dual-clutch transmissions for internal combustion engines. It provides details of the firm's new plastic piston, which relies on single-part sealing technology and, separately, also looks at an accumulator cylinder from FST that is integrated into a track drive for a tractor – made by a German manufacturer of machinery used in agriculture.
MP v. Secretary of State for the Home Department (CJEU)
Authors: Aagten Anne
Published: November 2018

On April 24, 2018, the Grand Chamber of the Court of Justice of the European Union (CJEU) delivered its judgment in MP v. Secretary of State for the Home Department. The judgment considers the interpretation and application of the concept of subsidiary protection. In the EU, two forms of international protection exist: refugee status and subsidiary protection status. The latter may apply to those who are refused refugee status. For subsidiary protection to be granted, it is assessed whether there is a real risk that the individual in question will, upon return, be subjected to serious harm in the form of the death penalty, torture, or inhuman or degrading treatment, or to indiscriminate violence as a result of an armed conflict.
United Nations Security Council Resolution 2379
Authors: Gilmore Scott A.
Published: November 2018

On September 21, 2017, the United Nations Security Council unanimously passed Resolution 2379 mandating the establishment of an Investigative Team to collect and preserve evidence for use in national courts of international crimes carried out by the terrorist group Islamic State in Iraq and the Levant (ISIL). Resolution 2379 marks a growing trend in the United Nations’ establishment of investigative mechanisms to support the domestic prosecution of international crimes, in lieu of referrals to the International Criminal Court or creation of ad hoc international or hybrid tribunals.
Rayleigh–Bénard convection with a melting boundary
Authors: Favier B. , Purseed J. , Duchemin L.
Published: November 2018

We study the evolution of a melting front between the solid and liquid phases of a pure incompressible material where fluid motions are driven by unstable temperature gradients. In a plane-layer geometry, this can be seen as classical Rayleigh–Bénard convection where the upper solid boundary is allowed to melt due to the heat flux brought by the fluid underneath. This free-boundary problem is studied numerically in two dimensions using a phase-field approach, classically used to study the melting and solidification of alloys, which we dynamically couple with the Navier–Stokes equations in the Boussinesq approximation. The advantage of this approach is that it requires only moderate modifications of classical numerical methods. We focus on the case where the solid is initially nearly isothermal, so that the evolution of the topography is related to the inhomogeneous heat flux from thermal convection, and does not depend on the conduction problem in the solid. From a very thin stable layer of fluid, convection cells appear as the depth – and therefore the effective Rayleigh number – of the layer increases. The continuous melting of the solid leads to dynamical transitions between different convection cell sizes and topography amplitudes. The Nusselt number can be larger than its value for a planar upper boundary, due to the feedback of the topography on the flow, which can stabilize large-scale laminar convection cells.
Human Metacognition Across Domains: Insights from Individual Differences and Neuroimaging
Authors: Rouault Marion , McWilliams Andrew , Allen Micah G. , Fleming Stephen M.
Published: November 2018

Metacognition is the capacity to evaluate and control one’s own cognitive processes. Metacognition operates over a range of cognitive domains, such as perception and memory, but the neurocognitive architecture supporting this ability remains controversial. Is metacognition enabled by a common, domain-general resource that is recruited to evaluate performance on a variety of tasks? Or is metacognition reliant on domain-specific modules? This article reviews recent literature on the domain-generality of human metacognition, drawing on evidence from individual differences and neuroimaging. A meta-analysis of behavioral studies found that perceptual metacognitive ability was correlated across different sensory modalities, but found no correlation between metacognition of perception and memory. However, evidence for domain-generality from behavioral data may suffer from a lack of power to identify correlations across model parameters indexing metacognitive efficiency. Neuroimaging data provide a complementary perspective on the domain-generality of metacognition, revealing co-existence of neural signatures that are common and distinct across tasks. We suggest that such an architecture may be appropriate for “tagging” generic feelings of confidence with domain-specific information, in turn forming the basis for priors about self-ability and modulation of higher-order behavioral control.
Symmetric spectrum current drive due to finite radial drift effects
Authors: Catto Peter J.
Published: November 2018

The drift surfaces of minority heated ions differ from flux surfaces due to finite poloidal gyroradius effects. As the minority poloidal gyroradius approaches radial scale lengths in the plasma, the difference between drift and flux surfaces can modify the heating and lead to a symmetric spectrum minority counter-current being driven. In response, a corresponding overall net co-current of comparable size is driven. This beneficial symmetric spectrum current drive in a tokamak is due to the parallel velocity asymmetry in the drift departure from a flux surface. As this new source of driven current is a side effect of minority heating it comes without any additional economic cost to reactor power balance. The symmetric spectrum current driven for near Maxwellian minorities is evaluated by an adjoint method and found to be modest. However, minority heating typically results in strong non-Maxwellian features on minority distributions so it may be possible to drive a significantly larger co-current. A related evaluation is performed for alpha particles in a deuterium minority heated plasma with a tritium majority. The low density of the alphas tends to keep this driven symmetric spectrum current small, but at very high heating levels a significant co-current might be driven. Other mechanisms to drive co-current with a symmetric spectrum are discussed and estimated, including asymmetric electron drag and focusing of the applied minority heating radio frequency fields.
Promoting cross-jurisdictional primary health care research: developing a set of common indicators across 12 community-based primary health care teams in Canada
Authors: Wong Sabrina T. , Langton Julia M. , Katz Alan , Fortin Martin , Godwin Marshall , Green Michael , Grunfeld Eva , Hassani Kasra , Kendall Claire , Liddy Clare , Ploeg Jenny , Wodchis Walter P. , Haggerty Jeannie L.
Published: November 2018

Aim

To describe the process by which the 12 community-based primary health care (CBPHC) research teams worked together and fostered cross-jurisdictional collaboration, including collection of common indicators with the goal of using the same measures and data sources.

Background

A pan-Canadian mechanism for common measurement of the impact of primary care innovations across Canada is lacking. The Canadian Institutes for Health Research and its partners funded 12 teams to conduct research and collaborate on development of a set of commonly collected indicators.

Methods

A working group representing the 12 teams was established. They undertook an iterative process to consider existing primary care indicators identified from the literature and by stakeholders. Indicators were agreed upon with the intention of addressing three objectives across the 12 teams: (1) describing the impact of improving access to CBPHC; (2) examining the impact of alternative models of chronic disease prevention and management in CBPHC; and (3) describing the structures and context that influence the implementation, delivery, cost, and potential for scale-up of CBPHC innovations.

Findings

Nineteen common indicators within the core dimensions of primary care were identified: access, comprehensiveness, coordination, effectiveness, and equity. We also agreed to collect data on health care costs and utilization within each team. Data sources include surveys, health administrative data, interviews, focus groups, and case studies. Collaboration across these teams sets the foundation for a unique opportunity for new knowledge generation, over and above any knowledge developed by any one team. Keys to success are each team’s willingness to engage and commitment to working across teams, funding to support this collaboration, and distributed leadership across the working group. Reaching consensus on collection of common indicators is challenging but achievable.
A RECOVERY OPERATOR FOR NONTRANSITIVE APPROACHES
Authors: BARRIO EDUARDO ALEJANDRO , PAILOS FEDERICO , SZMUC DAMIAN
Published: November 2018

In some recent articles, Cobreros, Egré, Ripley, & van Rooij have defended the idea that abandoning transitivity may lead to a solution to the trouble caused by semantic paradoxes. For that purpose, they develop the Strict-Tolerant approach, which leads them to entertain a nontransitive theory of truth, where the structural rule of Cut is not generally valid. However, that Cut fails in general in the target theory of truth does not mean that there are not certain safe instances of Cut involving semantic notions. In this article we intend to meet the challenge of answering how to regain all the safe instances of Cut, in the language of the theory, making essential use of a unary recovery operator. To fulfill this goal, we will work within the so-called Goodship Project, which suggests that in order to have nontrivial naïve theories it is sufficient to formulate the corresponding self-referential sentences with suitable biconditionals. Nevertheless, a secondary aim of this article is to propose a novel way to carry this project out, showing that the biconditionals in question can be totally classical. In the context of this article, these biconditionals will be essentially used in expressing the self-referential sentences and, thus, as a collateral result of our work we will prove that none of the recoveries expected of the target theory can be nontrivially achieved if self-reference is expressed through identities.
RELEVANCE FOR THE CLASSICAL LOGICIAN
Authors: BRAUER ETHAN
Published: November 2018

Although much technical and philosophical attention has been given to relevance logics, the notion of relevance itself is generally left at an intuitive level. It is difficult to find in the literature an explicit account of relevance in formal reasoning. In this article I offer a formal explication of the notion of relevance in deductive logic and argue that this notion has an interesting place in the study of classical logic. The main idea is that a premise is relevant to an argument when it contributes to the validity of that argument. I then argue that the sequents which best embody this ideal of relevance are the so-called perfect sequents—that is, sequents which are valid but have no proper subsequents that are valid. Church’s theorem entails that there is no recursively axiomatizable proof-system that proves all and only the perfect sequents, so the project that emerges from studying perfection in classical logic is not one of finding a perfect subsystem of classical logic, but is rather a comparative study of classifying subsystems of classical logic according to how well they approximate the ideal of perfection.
Elliott Receives 2018 Sulzman Award for Excellence in Education and Mentoring
Authors:   AGU
Published: November 2018

Emily Elliott will receive the 2018 Sulzman Award for Excellence in Education and Mentoring at AGU’s Fall Meeting 2018, to be held 10–14 December in Washington, D. C. The award is given to “one mid-career female scientist…for significant contributions as a role model and mentor for the next generation of biogeoscientists.”
Advancing FAIR Data in Earth, Space, and Environmental Science
Authors: Stall Shelley , Yarmey Lynn , Boehm Reid , Cousijn Helena , Cruse Patricia , Cutcher-Gershenfeld Joel , Dasler Robin , de Waard Anita , Duerr Ruth , Elger Kirsten , Fenner Martin , Glaves Helen , Hanson Brooks , Hausman Jessica , Heber Joerg , Hills Denise , Hoebelheinrich Nancy , Hou Sophie , Kinkade Danie , Koskela Rebecca , Martin Raleigh , Lehnert Kerstin , Murphy Fiona , Nosek Brian , Parsons Mark , Petters Jonathan , Plante Raymond , Robinson Erin , Samors Robert , Servilla Mark , Ulrich Robert , Witt Michael , Wyborn Lesley
Published: November 2018

The Enabling FAIR Data project has brought together a broad spectrum of Earth, space, and environmental science leaders to ensure that data are findable, accessible, interoperable, and reusable.
Crustal Magmatic System Beneath the East Pacific Rise (8°20′ to 10°10′N): Implications for Tectonomagmatic Segmentation and Crustal Melt Transport at Fast‐Spreading Ridges
Authors: Marjanović Milena , Carbotte Suzanne M. , Carton Hélène D. , Nedimović Mladen R. , Canales Juan Pablo , Mutter John C.
Published: November 2018

Detailed images of the midcrustal magmatic system beneath the East Pacific Rise (8°20′–10°10′N) are obtained from 2‐D and 3‐D‐swath processing of along axis seismic data and are used to characterize properties of the axial crust, cross‐axis variations, and relationships with structural segmentation of the axial zone. Axial magma lens (AML) reflections are imaged beneath much of the ridge axis (mean depth 1,640 ± 185 m), as are deeper sub‐AML (SAML) reflections (brightest events ~100–800 m below AML). Local shallow regions in the AML underlie two regions of shallow seafloor depth from 9°40′–55′N and 8°26′–33′N. Enhanced magma replenishment at present beneath both sites is inferred and may be linked to nearby off‐axis volcanic chains. SAML reflections, which are observed primarily from 9°20′ to 10°05′N, indicate a finely segmented magma reservoir similar to the AML above, composed of subhorizontal, 2‐ to 7 km‐long AML segments, often with stepwise changes in reflector depth from one segment to the next. We infer that these melt bodies are related to short‐lived melt instability zones. In many locations including where seismic constraints are strongest the intermediate scale (~15–40 km) structural segmentation of the ridge axis identified in this region coincides with (1) changes in average thickness of layer 2A (by 10%–15%), (2) changes in average depth of AML (<100 m), and (3) with the spacing of punctuated low velocity zones mapped in the uppermost mantle. The ~6 km dominant length of multiple AML segments within each of the larger structural segments may reflect the spacing of local sites of ascending magma from discrete melt reservoirs pooled beneath the crust.
Last Century Warming Over the Canadian Atlantic Shelves Linked to Weak Atlantic Meridional Overturning Circulation
Authors: Thibodeau Benoit , Not Christelle , Zhu Jiang , Schmittner Andreas , Noone David , Tabor Clay , Zhang Jiaxu , Liu Zhengyu
Published: November 2018

The Atlantic meridional overturning circulation (AMOC) is a key component of the global climate system. Recent studies suggested a twentieth‐century weakening of the AMOC of unprecedented amplitude (~15%) over the last millennium. Here we present a record of δ18O in benthic foraminifera from sediment cores retrieved from the Laurentian Channel and demonstrate that the δ18O trend is linked to the strength of the AMOC. In this 100‐year record, the AMOC signal decreased steadily to reach its minimum value in the late 1970s, where the weakest AMOC signal then remains constant until 2000. We also present a longer δ18O record of 1,500 years and highlight the uniqueness of the last century δ18O trend. Moreover, the Little Ice Age period is characterized by statistically heavier δ18O, suggesting a relatively weak AMOC. Implications for understanding the mechanisms driving the intensity of AMOC under global warming and high‐latitude freshwater input are discussed.
A Proxy for the Upstream IMF Clock Angle Using MAVEN Magnetic Field Data
Authors: Hurley Dana M. , Dong Yaxue , Fang Xiaohua , Brain David A.
Published: November 2018

Without an upstream monitor at Mars to provide a contemporaneous measurement of solar wind conditions, it is useful to have techniques of inferring the upstream solar wind conditions using downstream data. We develop a method to estimate the upstream interplanetary magnetic field (IMF) clock angle, defined as the orientation of the IMF vector in the plane perpendicular to the solar wind velocity, at Mars using magnetometer data from the Mars Atmosphere and Volatile Evolution (MAVEN) mission. The technique fits MAVEN magnetometer data from within the Martian magnetosheath to a model of the draped magnetic field direction in a coordinate system aligned with the motional electric field. The results provide a proxy for the clock angle that agrees with upstream measurements and reproduces the observed distribution of clock angles. Even if upstream observations are available for a given orbit, the proxy provides an estimate of the clock angle at the time when the spacecraft is in the magnetosheath, which may correct for inherent temporal variability, because the solar wind varies on timescales shorter than the 4.5‐hr MAVEN orbit. The clock angle proxy can be applied for any orientation of the MAVEN orbit, even when MAVEN does not traverse into the upstream solar wind.
Determination of the Equatorial Electron Differential Flux From Observations at Low Earth Orbit
Authors: Allison Hayley J. , Horne Richard B. , Glauert Sarah A. , Del Zanna Giulio
Published: November 2018

Variations in the high‐energy relativistic electron flux of the radiation belts depend on transport, acceleration, and loss processes, and importantly on the lower‐energy seed population. However, data on the seed population is limited to a few satellite missions. Here we present a new method that utilizes data from the Medium Energy Proton/Electron Detector on board the low‐altitude Polar Operational Environmental Satellites to retrieve the seed population at a pitch angle of 90°. The integral flux values measured by Medium Energy Proton/Electron Detector relate to a low equatorial pitch angle and were converted to omnidirectional flux using parameters obtained from fitting one or two
functions to pitch angle distributions given by three and a half years of Van Allen Probes data. Two methods to convert from integral to differential flux are explored. One utilizes integral and differential flux energy distributions from the AE9 model, the second employs an iterative fitting approach based on a Reverse Monte Carlo (RMC) method. The omnidirectional differential flux was converted to an equatorial pitch angle of 90°, again using statistical pitch angle distributions from Van Allen Probe data. We validate the resulting 90° flux for 100‐ to 600‐keV electrons against measurements from the Van Allen Probes and show an average agreement within a factor of 4 for L* > 3.7. The resulting data set offers a high time resolution, across multiple magnetic local time planes, and may be used to formulate event‐specific low‐energy boundary conditions for radiation belt models.
Multispacecraft Observations of Tailward Propagation of Transient Foreshock Perturbations to Midtail Magnetosheath
Authors: Wang Chih‐Ping , Liu Terry Z. , Xing Xiaoyan , Masson Arnaud
Published: November 2018

We present three events from multiple spacecraft observations to show that a dayside transient foreshock perturbation associated with an interplanetary magnetic field directional discontinuity can propagate in the midtail magnetosheath and affect the magnetopause. In the first event, perturbations in density and flow were first observed in the dayside foreshock and later in the tail magnetosheath at X ~ −40 RE, a correlation suggests that the foreshock‐originating perturbations propagated to the midtail. The second event shows that foreshock‐originating perturbations were observed in the tail magnetosheath at two radial distances (X ~ −30 and −50 RE) at different times. One plausible explanation for this delay is a tailward propagation of these perturbations along with the directional discontinuity. In the third event, a significant change in the dynamic pressure associated with a foreshock perturbation caused a transient magnetopause outward/inward motion that was first observed on the dayside and later in the midtail at X ~ −55 RE. These events suggest that foreshock perturbations could propagate tailward and continuously affect the nightside magnetopause.
A Simple Finite Difference‐Based Approximation for Biogeochemical Tangent Linear and Adjoint Models
Authors: Mattern Jann Paul , Edwards Christopher A.
Published: November 2018

We present a technique that accurately approximates tangent linear and adjoint models for data assimilation applications using only evaluations of the nonlinear model. The approximation offers a simple way to create tangent linear and adjoint model codes that are easily maintainable, as only major changes to the nonlinear model formulation necessitate modifications of the tangent linear or adjoint model code. The approach is particularly well suited to marine biogeochemical models and takes advantage of typical features of these types of models to be computationally viable. We illustrate the approximation in a realistic application, using a three‐dimensional coupled physical‐biogeochemical 4D‐Var data assimilation system, set in the California Current system, in which the approximation is only applied to the 11 state variable biogeochemical model. In this application, the approximation‐based model solution tracks the reference solution accurately over thirty 4‐day assimilation cycles but leads to a ∼10% increase in the computational cost compared to the hand‐coded reference.
Comment on “Reconstruction of the Exhumed Mantle Across the North Iberian Margin by Crustal‐Scale 3‐D Gravity Inversion and Geological Cross Section” by Pedrera et al.
Authors: Pedreira D. , Pulgar J. A. , Díaz J. , Alonso J. L. , Gallastegui J. , Teixell A.
Published: November 2018

Key Points

The crustal model proposed by Pedrera et al. (2017) is not supported by the available deep seismic data set

The gravity model is built upon inaccurately retrieved residual gravity anomalies and uses inappropriate density values

The sequential restoration shows geometric‐structural inconsistencies, mechanical difficulties, and problematic isostatic and kinematic implications
Comparing effects of CDK inhibition and E2F1/2 ablation on neuronal cell death pathways in vitro and after traumatic brain injury
Authors: Aubrecht Taryn G. , Faden Alan I. , Sabirzhanov Boris , Glaser Ethan P. , Roelofs Brian A. , Polster Brian M. , Makarevich Oleg , Stoica Bogdan A.
Published: November 2018

Traumatic brain injury (TBI) activates multiple neuronal cell death mechanisms, leading to post-traumatic neuronal loss and neurological deficits. TBI-induced cell cycle activation (CCA) in post-mitotic neurons causes regulated cell death involving cyclin-dependent kinase (CDK) activation and initiation of an E2F transcription factor-mediated pro-apoptotic program. Here we examine the mechanisms of CCA-dependent neuronal apoptosis in primary neurons in vitro and in mice exposed to controlled cortical impact (CCI). In contrast to our prior work demonstrating robust neuroprotective effects by CDK inhibitors after TBI, examination of neuronal apoptotic mechanisms in E2F1−/−/E2F2−/− or E2F2−/− transgenic mice following CCI suggests that E2F1 and/or E2F2 likely play only a modest role in neuronal cell loss after brain trauma. To elucidate more critical CCA molecular pathways involved in post-traumatic neuronal cell death, we investigated the neuroprotective effects and mechanisms of the potent CDK inhibitor CR8 in a DNA damage model of cell death in primary cortical neurons. CR8 treatment significantly reduced caspase activation and cleavage of caspase substrates, attenuating neuronal cell death. CR8 neuroprotective effects appeared to reflect inhibition of multiple pathways converging on the mitochondrion, including injury-induced elevation of pro-apoptotic Bcl-2 homology region 3 (BH3)-only proteins Puma and Noxa, thereby attenuating mitochondrial permeabilization and release of cytochrome c and AIF, with reduction of both caspase-dependent and -independent apoptosis. CR8 administration also limited injury-induced deficits in mitochondrial respiration. These neuroprotective effects may be explained by CR8-mediated inhibition of key upstream injury responses, including attenuation of c-Jun phosphorylation/activation as well as inhibition of p53 transactivation of BH3-only targets.
The role of submesoscale currents in structuring marine ecosystems
Authors: Lévy Marina , Franks Peter J. S. , Smith K. Shafer
Published: November 2018

From microbes to large predators, there is increasing evidence that marine life is shaped by short-lived submesoscales currents that are difficult to observe, model, and explain theoretically. Whether and how these intense three-dimensional currents structure the productivity and diversity of marine ecosystems is a subject of active debate. Our synthesis of observations and models suggests that the shallow penetration of submesoscale vertical currents might limit their impact on productivity, though ecological interactions at the submesoscale may be important in structuring oceanic biodiversity.
Dehydrative π-extension to nanographenes with zig-zag edges
Authors: Lungerich Dominik , Papaianina Olena , Feofanov Mikhail , Liu Jia , Devarajulu Mirunalini , Troyanov Sergey I. , Maier Sabine , Amsharov Konstantin
Published: November 2018

Zig-zag nanographenes are promising candidates for the applications in organic electronics due to the electronic properties induced by their periphery. However, the synthetic access to these compounds remains virtually unexplored. There is a lack in efficient and mild strategies origins in the reduced stability, increased reactivity, and low solubility of these compounds. Herein we report a facile access to pristine zig-zag nanographenes, utilizing an acid-promoted intramolecular reductive cyclization of arylaldehydes, and demonstrate a three-step route to nanographenes constituted of angularly fused tetracenes or pentacenes. The mild conditions are scalable to gram quantities and give insoluble nanostructures in close to quantitative yields. The strategy allows the synthesis of elusive low bandgap nanographenes, with values as low as 1.62 eV. Compared to their linear homologues, the structures have an increased stability in the solid-state, even though computational analyses show distinct diradical character. The structures were confirmed by X–ray diffraction or scanning tunneling microscopy.
Large-area and adaptable electrospun silicon-based thermoelectric nanomaterials with high energy conversion efficiencies
Authors: Morata Alex , Pacios Mercè , Gadea Gerard , Flox Cristina , Cadavid Doris , Cabot Andreu , Tarancón Albert
Published: November 2018

Large amounts of waste heat generated in our fossil-fuel based economy can be converted into useful electric power by using thermoelectric generators. However, the low-efficiency, scarcity, high-cost and poor production scalability of conventional thermoelectric materials are hindering their mass deployment. Nanoengineering has proven to be an excellent approach for enhancing thermoelectric properties of abundant and cheap materials such as silicon. Nevertheless, the implementation of these nanostructures is still a major challenge especially for covering the large areas required for massive waste heat recovery. Here we present a family of nano-enabled materials in the form of large-area paper-like fabrics made of nanotubes as a cost-effective and scalable solution for thermoelectric generation. A case study of a fabric of p-type silicon nanotubes was developed showing a five-fold improvement of the thermoelectric figure of merit. Outstanding power densities above 100 W/m2 at 700 °C are therefore demonstrated opening a market for waste heat recovery.
Higher-Order Interactions in Quantum Optomechanics: Analysis of Quadratic Terms
Authors: Khorasani Sina
Published: November 2018

This article presents a full operator analytical method for studying the quadratic nonlinear interactions in quantum optomechanics. The method is based on the application of higher-order operators, using a six-dimensional basis of second order operators which constitute an exactly closed commutators. We consider both types of standard position-field and the recently predicted non-standard momentum-field quadratic interactions, which is significant when the ratio of mechanical frequency to optical frequency is not negligible. This unexplored regime of large mechanical frequency can be investigated in few platforms including the superconducting electromechanics and simulating quantum cavity electrodynamic circuits. It has been shown that the existence of non-standard quadratic interaction could be observable under appropriate conditions.