bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiative lifetime measurements of metastable levels in Kr3+ using electrostatic ion beam trap
Authors: Saito M. , Kubota H. , Majima T. , Imai M. , Tsuchida H. , Haruyama Y.
Published: April 2019

The radiative lifetimes of the metastable 4s24p3 2P3/2 and 2P1/2 levels in Kr3+ ions were measured using an electrostatic ion beam trap. The lifetimes were determined by measuring the number of photons emitted during the 2P3/2 → 4S3/2 and 2P1/2 → 4S3/2 forbidden transitions of the stored Kr3+ ions, as a function of the storage time. The obtained lifetime values for the 2P3/2 and 2P1/2 states were 23.3 ± 1.4 and 52.8 ± 3.8 ms, respectively. For the 2P3/2 state, this is the first experimental investigation of the radiative lifetime. Considering the experimental errors, the obtained lifetimes are consistent with the previously reported theoretical predictions for each state and the experimental result for the 2P1/2 state.
Quantitative determination of macroelement and microelement content of fresh and processed bamboo shoots by wavelength dispersive X‐ray fluorescence spectrometry
Authors: Bajwa Harjit Kaur , Santosh Oinam , Koul Ashwani , Bisht M.S. , Nirmala Chongtham
Published: April 2019

Bamboo shoots are considered as healthy and nutritional food as they supply proteins, dietary fiber, phenols, phytosterols, vitamins, and minerals in considerable quantities and capture a novel place in the spectrum of plant foods. Besides nutrients and bioactive compounds, shoots also contain antinutrient (cyanogen) that needs to be removed by adequate processing prior to consumption. This study was undertaken to investigate the effects of fermentation, brine preservation, and boiling on levels of mineral elements in shoots of Dendrocalamus hamiltonii using wavelength dispersive X‐ray fluorescence (WD‐XRF) spectrometry. WD‐XRF spectrometry is a method that causes the least destruction to the raw plant material as no harsh chemicals are used and gives the most accurate results. Fermentation process resulted in significant increase in the levels of Rb (9%), S (11%), Mg (12%), Zn (46%), Ca (56%), and Fe (87%); however, Na (18.79 g/100 g, dry weight), Cl (24.73 g/100 g, dry weight), and Br (20.0 mg/100 g, dry weight) content increased drastically after brine preservation. Boiling increased the levels of Fe by 139% but did not affect the Rb (20.0 mg/100 g, dry weight) and Zn content (10.2 mg/100 g, dry weight) of the shoots. In general, fermentation, which led to the lowest loss of mineral elements, appears the best method in enhancement and retention of the mineral content in bamboo shoots and holds the prospect at industrial and society levels.
Review of highly charged ion production with ECR ion source and the future opportunities for HCI physics
Authors: Sun L. , Zhao H.W. , Lu W. , Guo J.W. , Yang Y. , Jia H. , Lu L. , Wu W.
Published: April 2019

In recent years, there is very intense worldwide research and development work on electron cyclotron resonance ion source (ECRIS). Remarkable progress represented by the third generation superconducting ECRIS has been made with regards of intense highly charged ion beam production such as >600 eμA Ar16+, >10 eμA Ar18+, and hundreds of enA He‐like Kr34+. A low energy heavy ion platform named Low Energy heavy ion Accelerator Facility (LEAF) that features a next generation 45 GHz ECRIS, a 300 kV high voltage platform, a 0.5 MeV/u radio‐frequency quadrupole, and several multidisciplinary experimental terminals is under construction at the Institute of Modern Physics (IMP). This paper will report on the recent progress with ECRIS dedicated to highly charged ions and the status of LEAF at IMP that will provide new opportunities for highly charged ion physics in the near future.
Activity budget and spatial distribution of Bennett's wallabies (Macropus rufogriseus) in open versus closed exhibit designs
Authors: Beaudin‐Judd Julie , Weladji Robert B. , Lazure Louis , Paré Patrick
Published: April 2019

Although many studies investigating the impacts of zoo exhibit designs on captive animals exist, none have been performed on how they influence the behavior and welfare of captive Bennett's wallabies (Macropus rufogriseus). Here, we assess the impact of exhibit design on the activity budget and spatial distribution of Bennett's wallabies. We compared animal behavior in two open exhibits (i.e. physical interaction between animals and visitors permitted) to two closed exhibits (i.e. physical interaction between animals and visitors prohibited). Behavioral data were collected using focal sampling, and spatial distribution was recorded on exhibit maps at regular time intervals. We found a significant increase in feeding and interactive behaviors in closed exhibits in comparison to open exhibits. However, other behaviors such as resting, locomotion, and vigilance did not vary with design. Functional use of space was similar between both designs; however, the effect of habituation may be relevant to consider in future studies. Although some support for visitor effects were present, our study provided no evidence for strong impacts of exhibit design on Bennett's wallaby welfare. Our study emphasizes the need for additional research into the impacts of how zoo environments affect Bennett's wallaby behavior and welfare.
Timelike structures of ten-dimensional supersymmetry
Authors: Legramandi Andrea , Martucci Luca , Tomasiello Alessandro
Published: April 2019

Abstract

In several contexts, supersymmetry can be reformulated in terms of calibrations, namely forms whose integrals measure minimal energies. It has been conjectured that this should be possible in general. For type II supergravity, we present a new system of equations which realizes this expectation. Besides the customary D-brane calibrations, it also includes NS5-brane and KK5-monopole calibrations. It is equivalent to supersymmetry under the assumption that the Killing vector associated to supersymmetry is timelike. No assumption is made on a factorization of spacetime. We also obtain a version of the system which is manifestly S-invariant and we present an application to near-horizon backgrounds. Using calibration, a definition of central charges in purely gravitational terms is given.
A structural test for the conformal invariance of the critical 3d Ising model
Authors: Meneses Simão , Penedones João , Rychkov Slava , Viana Parente Lopes J. M. , Yvernay Pierre
Published: April 2019

How can a renormalization group fixed point be scale invariant without being conformal? Polchinski (1988) showed that this may happen if the theory contains a virial current — a non-conserved vector operator of dimension exactly (d − 1), whose divergence expresses the trace of the stress tensor. We point out that this scenario can be probed via lattice Monte Carlo simulations, using the critical 3d Ising model as an example. Our results put a lower bound Δ
V
> 5.0 on the scaling dimension of the lowest virial current candidate V, well above 2 expected for the true virial current. This implies that the critical 3d Ising model has no virial current, providing a structural explanation for the conformal invariance of the model.
Covariant Poisson’s equation in torsional Newton-Cartan gravity
Authors: Abedini Mohammad , Afshar Hamid R. , Ghodsi Ahmad
Published: April 2019

Abstract

We derive the covariant Poisson’s equation of (d + 1)-dimensional Newton-Cartan gravity with (twistless) torsion by applying the ‘non-relativistic conformal method’ introduced in [1]. We apply this method on-shell to a Schrödinger field theory on the curved Newton-Hooke background. The covariance of the field equation in the presence of the non-relativistic cosmological constant, entails fixing all coefficients in the covariant Poisson’s equation for (twistless) torsional Newton-Cartan gravity. We further derive Ehlers conditions and an equation associated to the torsion in this method.
Dark matter in Hidden Valley models with stable and unstable light dark mesons
Authors: Beauchesne Hugues , Bertuzzo Enrico , Grilli di Cortona Giovanni
Published: April 2019

Abstract

It is a distinct possibility that a Hidden Valley sector would have a spectrum of light particles consisting of both stable and unstable dark mesons. The simultaneous presence of these two types of particles can lead to novel mechanisms for generating the correct dark matter relic abundance, which in turn can reflect themselves into new exotic signatures at colliders. We study the viability of such sectors for various Hidden Valley models and map the valid parameter space to possible collider signatures. Mediators studied include various scalar bifundamentals and a heavy Z′. It is shown that in general bounds from direct and indirect detection can easily be avoided. In most of the allowed parameter space, the relic density is determined by stable mesons annihilating to unstable ones which in turn decay quickly to Standard Model particles. Dark mesons that decay mainly to heavier Standard Model fermions allow for more valid parameter space, though dark mesons are still allowed to decay exclusively to some of the lighter fermions. Possible exotic collider signatures include displaced vertices, emerging jets and semivisible jets.
A modular toolkit for bulk reconstruction
Authors: Faulkner Thomas , Li Min , Wang Huajia
Published: April 2019

Abstract

We introduce new tools for studying modular flow in AdS/CFT. These tools allow us to efficiently extract bulk information related to causality and locality. For example, we discuss the relation between analyticity in modular time and entanglement wedge nesting which can then be used to extract the location of the Ryu-Takayanagi (RT) surface directly from the boundary theory. Probing the RT surface close to the boundary our results reduce to the recent proof of the Quantum Null Energy Condition. We focus on heavy probe operators whose correlation functions are determined by spacelike geodesics. These geodesics interplay with the RT surface via a set of rules that we conjecture and give evidence for using the replica trick.
Seeing higher-dimensional grand unification in primordial non-gaussianities
Authors: Kumar Soubhik , Sundrum Raman
Published: April 2019

Abstract

The observed low-energy values of the SU(3) × SU(2) × U(1) gauge couplings, extrapolated via the minimal Standard Model Renormalization Group evolution, hint at the exciting possibility of a Grand Unified Theory (GUT) atMU∼ 1014GeV — a scale, however, too high to probe directly via collider searches. Fortunately, since the Hubble scaleHcan be as high as 5 × 1013GeV ∼MUduring the inflationary era, such GUT scale states can be cosmologically produced at that time and leave directon-shellsignatures such as their masses and spins, via primordial non-Gaussianity (NG). We explore this possibility in one of its simplest realizations given by the extra-dimensional framework of orbifold GUTs, in which proton decay can be straightforwardly suppressed to be within the stringent bounds. Here, along with the massive GUT states there must also beH-mass spin-2 Kaluza-Klein (KK) gravitons, collectively giving rise to striking NG signatures. In our set-up we localize the inflaton on one of the boundaries of an extra dimension. The inflationary vacuum energy can readily lead to formation of a horizon in the bulk, where the KK modes then form acontinuumabove a mass gap of ∼$$ \mathcal{O} $$O(H). We find that the optimal case for observable NG signals is when the extra dimension is stabilized close to the onset of this horizon, ensuring adiscreteKK spectrum such that the lightest KK modes can be cosmologically produced without significant Boltzmann suppressions. Although we mostly focus on the case where there is no higher-dimensional cosmological constant, we also obtain considerable holographic insights from the AdS5/CFT4correspondence when such a cosmological constant is included.
Uterine Artery Embolization and Methotrexate Infusion as Sole Management for Caesarean Scar and Cervical Ectopic Pregnancies: A Single-Center Experience and Literature Review
Authors: Elmokadem Ali H. , Abdel-Wahab Rihame M. , El-Zayadi Ahmed A. , Elrakhawy Mohamed M.
Published: April 2019

Introduction

The incidence of caesarean scar pregnancy (CSP) and cervical pregnancy (CP) has increased significantly in recent years. The related hemorrhage can be lethal and often needs hysterectomy. This study aims to assess the technical and clinical results of uterine artery embolization (UAE) combined with intra-arterial methotrexate (MTX) infusion for CSP and CP.

Methods

A retrospective study was conducted for 11 patients (age range from 25–40 years, mean; 31.8 y) with CSP (7/11) and CP (4/11). The diagnosis was confirmed by elevated b-hCG levels (mean 31.245 mIU/mL) with sonography and/or magnetic resonance imaging. They were treated with UAE using particulate embolic material. In all patients, the infusion of MTX (50 mg/m2) was performed before UAE. Follow-up periods after UAE ranged between 6-24 months included weekly sonography and b-hCG level assessment. A literature review was performed using standard online search tools.

Results

In 10 patients, UAE controlled active vaginal bleeding and reduced post-procedural b-hCG levels significantly by the second week. One patient presented with persistent elevated b-hCG level and vaginal rebleeding. The rebleeding was successfully controlled by second UAE procedure. The ectopic pregnancies were resolved, and the uterus was preserved in all patients. No major complications were detected. Normal menses resumed within 2 months after UAE. Two patients had subsequent natural successful intrauterine pregnancies.

Conclusion

UAE combined with intra-arterial MTX infusion resulted in resolution of ectopic pregnancies with control of hemorrhage and without hysterectomy in this small group of patients.
On Principals and Agency: Reassembling Trust in Indian Ocean Commerce
Authors: Mathew Johan
Published: April 2019

The role of trust in long-distance trade has been a topic of inquiry and debate among economists, sociologists, and historians. Much of this literature hinges on the social, legal, and economic structures that undergird, if not obviate, the concept of trust. This article draws on assemblage theory to suggest that trust in Indian Ocean trade is better understood as a key component of a commercial assemblage. Laws or social mores are not external to but rather enrolled within an assemblage constituted by people, commodities, profits, and “feelings,” as well as judicial systems. This conceptualization of trust is demonstrated through a close analysis of one trading relationship between a Somali merchant and an Indian merchant based in Aden and trading in the Idrisi Emirate of Asir. They established a partnership to exploit elevated prices in Asir during the First World War. After several months of trading, accusations of fraud and embezzling unraveled the partnership and entangled both men in years of legal battles. By tracing the changing socio-material assemblage of this partnership, the article demonstrates how trust should be understood as a dynamic and contingent factor in the operation of commercial agency.
Fugitives, Vagrants, and Found Dead Bodies: Identifying the Individual in Tsarist Russia
Authors: Smith Alison K.
Published: April 2019

In the middle of the nineteenth century, in the Russian Empire, a new set of state-sponsored provincial newspapers began to include notices seeking fugitives and trying to identify arrested vagrants and found dead bodies. The notices were part of a larger effort to match individuals with specific legal identities based in social estate (soslovie). In principle, every individual subject of the Russian Empire belonged to a specific owner (in the case of serfs) or to a specificsosloviesociety (in the case of nearly everyone else). The notices were an effort to link people who had left their proper place to their “real” identity. To accomplish this, the notices also made use of a kind of simple biometrics or anthropometrics in order to move beyond an individual's telling of his or her own identity. By listing height, hair and eye color, the shape of nose, mouth, and chin, and other identifying features, the notices were intended to allow for more exact identification. This version of identification developed out of previous practices grounded in the documentary requirements of the tsarist state, and they were slightly ahead of their time in the context of nineteenth-century developments in the sphere of identification practices. They were also distinct from other kinds of anthropometric practices of classification developed at the same time or soon thereafter—where many sought to use physical measurements to classify people by race or by inclination to criminality, the Russian system had no such goals.
Pedagogies of Prayer: Teaching Orthodoxy in South India
Authors: Naumescu Vlad
Published: April 2019

This article focuses on religious pedagogies as an essential part of the practice and the making of modern religion. It takes the case of the Syrian Orthodox communities in Kerala, South India to examine how shifts in pedagogical models and practice have reframed their understanding of knowledge and God. The paper highlights two moments of transformation—the nineteenth-century missionary reforms and twenty-first-century Sunday school reforms—that brought “old” and “new” pedagogies into conflict, redefining the modes of knowing and religious subjectivities they presuppose. For this I draw from historical and pedagogical materials, and ethnographic fieldwork in churches and Sunday schools. The paper diverges from widespread narratives on the missionary encounter by showing how colonial efforts to replace ritual pedagogies with modern schooling were channeled into a textbook culture that remained close to Orthodox ritualism. The “new” pedagogy turned learning into a ritualized practice that continued to emphasize correct performance over interiorized belief. Contrasting this with todays’ curriculum revisions, I argue that educational reforms remain a privileged mode of infusing new meanings into religious practice and shaping new orthodoxies, especially under the threat of heterodoxy. This reflects a broader dynamic within Orthodox Christianity that takes moments of crisis or change as opportunities to turn orthopraxy into orthodoxy and renew the faith. The paper engages with postcolonial debates on religion, education, and modernity, and points to more pervasive assumptions about what makes Orthodox Christianity and the modes of knowing and ethical formation in Eastern Christianity.
Archived Voices, Acoustic Traces, and the Reverberations of Kurdish History in Modern Turkey
Authors: Schäfers Marlene
Published: April 2019

This article investigates how middle-aged to elderly Kurdish women in Turkey engage with large collections of Kurdish music recordings in their possession. Framing them as archives, women mobilize these collections as central elements in a larger, ongoing Kurdish project of historical critique, which seeks to resist hegemonic state narratives that have long denied and marginalized Kurdish voices. While recognizing the critical intervention such archives make, the article contends that, to be heard as “history” with a legitimate claim to authority, subaltern voices often have to rely on the very hegemonic forms, genres, and discourses they set out to challenge. This means that subaltern projects of historical critique walk a fine line between critique and complicity, an insight that nuances narratives that would approach subaltern voices predominantly from a perspective of resistance. At the same time, this article argues that a more complete picture of subaltern archives requires us to attend to the voices they contain not just as metaphors for resistance or political representation but also as acoustic objects that have social effects because of the way they sound. By outlining the affective qualities that voice recordings held for the Kurdish women who archived them, the article shows how their collections participated in carving out specific, gendered subject positions as well as forging a broader Kurdish sociality. Paying attention to history's “acoustic register” (Hunt 2008), this suggests, promises to open up perspectives on subaltern historiography that go beyond binary frameworks of resistance and domination, critique and complicity.
Sensitivity to hypoxia and microbial activity are instrumental in pericarp-imposed dormancy expression in sunflower (Helianthus annuus L.)
Authors: Dominguez Constanza P. , Rodríguez María V. , Batlla Diego , García de Salamone Inés E. , Mantese Anita I. , Andreani Ana L. , Benech-Arnold Roberto L.
Published: April 2019

We used two sunflower genotypes displaying pericarp-imposed dormancy at high incubation temperatures (i.e. 30°C) to investigate the role of the pericarp as a limitation to oxygen availability to the embryo (hypoxia), and its impact on embryo abscisic acid (ABA) content and sensitivity to ABA. Results showed that both genotypes displayed very different oxygen threshold values for inhibition of embryo germination when incubation was performed at 30°C. Expression of dormancy in one genotype was therefore related to exacerbated embryo sensitivity to hypoxia, whereas in the other genotype, the pericarp appeared to act as a more severe restraint to oxygen entry. Increased sensitivity to hypoxia was, in part, related to increased sensitivity to ABA, but not to alterations in ABA metabolism. The activity of pericarp-microbial communities (bacteria and fungi) at high temperatures was also assessed as a potential determinant of hypoxia to the embryo. Oxygen consumption in pericarps incubated at 30°C was attenuated with antibiotics, which concomitantly promoted achene germination. In agreement with the observed more severe oxygen deprivation to the embryo exerted by the pericarp, the bacterial load in the pericarp was significantly higher in the commercial hybrid than in the inbred line; however, the application of antibiotics strongly reduced the bacterial colony counts for each genotype. Different bacterial and fungal communities, assessed through their profiles of carbon-source utilization, were determined between genotypes and after treatment with antibiotics. This work highlights the relationship between enhancement of sensitivity to hypoxia with incubation temperature and seed dormancy expression, and suggests that microbial activity might be part of the mechanism through which hypoxia is imposed.
The Subtropical Ocean's Biological Carbon Pump Determined From O2 and DIC/DI13C Tracers
Authors: Yang Bo , Emerson Steven R. , Quay Paul D.
Published: April 2019

The ocean's biological organic carbon pump regulates the pCO2 of the atmosphere and helps maintain the oxygen distributions in the ocean. Global models of this flux are poorly verified with observations. We used upper‐ocean budgets of O2 and the 13C/12C of dissolved inorganic carbon (DIC) to estimate the biological pump in the subtropical gyres. These two tracers yield, within errors, similar result (~2.0 mol C·m−2·year−1) at three Northern Hemisphere subtropical locations. Values for three Southern Hemisphere subtropical regions are lower and more variable determined by the O2 mass balance than by the DI13C method (−0.5 to 0.8 mol C·m−2·year−1 and 0.9 to 1.3 mol C·m−2·year−1, respectively). Both methods suggest that the subtropical ocean is, on the whole, autotropic. The gas exchange residence times of O2 and dissolved inorganic carbon result in different spatial and temporal averaging creating complementary tracers for biological pump model verification.
Seismic Moments of Intermediate‐Depth Earthquakes Beneath the Hindu Kush: Active Stretching of a Blob of Sinking Thickened Mantle Lithosphere?
Authors: Molnar Peter , Bendick Rebecca
Published: April 2019

Intermediate‐depth seismicity beneath the Hindu Kush may reveal the Earth's best example of a stretching blob of mantle lithosphere sinking through the asthenosphere. Seismically, this region is the Earth's most active at intermediate depths (70–300 km). Fault plane solutions show nearly vertical stretching of the region in which the earthquakes occur, and a summation of seismic moment tensors implies that on average material at a depth of 300 km moves downward at ~40 mm/year relative to the overlying crust. As shown by Kufner et al. (2017, https://doi.org/10.1016/j.epsl.2016.12.043) and Zhan and Kanamori (2016, https://doi.org/10.1002/2016GL069603), the central part of the zone stretches so rapidly that this rate there is ~100 mm/year, much faster than the present‐day convergence rate of ~15 mm/year at the surface and across the Hindu Kush. The pattern of stretching, with maximum strain rates in the middle depths of the intermediate‐depth range, resembles that beneath the southeastern Carpathians, where Lorinczi and Houseman (2009, https://doi.org/10.1016/j.tecto.2008.05.024) have shown that seismicity is consistent with a blob of mantle lithosphere stretching rapidly and sinking into the asthenosphere, though more slowly than occurs beneath the Hindu Kush.
How Do Continents Deform During Mantle Exhumation? Insights From the Northern Iberia Inverted Paleopassive Margin, Western Pyrenees (France)
Authors: Asti Riccardo , Lagabrielle Yves , Fourcade Serge , Corre Benjamin , Monié Patrick
Published: April 2019

Extreme crustal thinning associated with subcontinental mantle exhumation characterizes the distal domain of some current, magma‐poor continental passive margins. Since these domains lie at abyssal depths and are hardly accessible, their internal structure and the finite strain of the stretched crust are not directly observed and are only inferred. A detailed field study was conducted on exceptionally preserved Cretaceous distal margin analogs in two key areas of the western Pyrenees (North Pyrenean Zone): the Urdach and Saraillé ultramafic massifs in the Chaînons Béarnais range. A tight sampling allowed us to characterize the conditions of the ductile deformation of the continental crust exhumed together with the mantle. New 40Ar/39Ar dating on muscovite constrains the timing of the last deformation of the continental crust in relation with mantle exhumation to the late Albian. We propose a new reconstruction for the distal part of the North Iberian paleopassive margin based on the following constraints: (i) post‐Silurian Paleozoic rocks are never found in the distal domain; (ii) lower crustal levels are not found in the exhumed crustal units; (iii) extension in the pre‐Silurian series is accomplished by lenticular deformation and pervasive ductile flattening through anastomosing extensional mylonitic shear zones at temperatures of 350–450 °C; and (iv) at the final step of exhumation, only pre‐Silurian crustal lenses remained welded on the exhumed mantle. Finally, we discuss the importance of the crustal structure inherited from previous Paleozoic and Mesozoic tectonic events and we state that mantle exhumation was partially achieved before the Cretaceous North Pyrenean rifting.
X‐Ray Computed Microtomography Imaging of Abiotic Carbonate Precipitation in Porous Media From a Supersaturated Solution: Insights Into Effect of CO2 Mineral Trapping on Permeability
Authors: Baek Seung‐Hun , Hong Jung‐Wuk , Kim Kwang Yeom , Yeom Sun , Kwon Tae‐Hyuk
Published: April 2019

Abiotic carbonate precipitation has garnered significant interest as a mechanism for mineral trapping of carbon dioxide (CO2) in geologic carbon storage, as a natural diagenetic process frequently occurring in marine environments, and as an engineering approach for soil improvement. This study explored pore‐scale precipitation of calcium carbonate (CaCO3) and its effect on the permeability of porous media, using X‐ray computed microtomography (CMT). In a column experiment, CaCO3 was precipitated in a sand pack from a supersaturated CaCO3 solution, while porosity, pore volume fraction of carbonate, and permeability were being monitored and X‐ray CMT images were being acquired. Permeability reduction by ~99.94% was observed when precipitated carbonate occupied ~46–47% of pore volume. The X‐ray CMT images showed that carbonate crystals were initially nucleated onto sand grain surfaces, which facilitated subsequent precipitation, indicating a predominantly grain‐coating behavior. The scanning electron microscopy revealed the carbonate crystals of ~1–20 μm in size and the presence of internal pores in the carbonate layers at the submicrometer scale. Variations in carbonate layer thickness and geometric tortuosity, and preferential carbonate precipitation behavior with local clogging were examined through morphological analysis and phase segmentation. Particularly, the pore‐scale precipitation pattern and hence the pore geometry were found to evolve with continued precipitation from a grain‐coating behavior, through a pore‐filling behavior, and finally into a dramatic pore‐throat‐clogging behavior. Our results provide unique experiment data for predictive modeling of long‐term CO2 transport and provide new insights into the changes in physical and transport properties during CO2 mineral trapping.
Mineral Precipitation in Fractures: Using the Level‐Set Method to Quantify the Role of Mineral Heterogeneity on Transport Properties
Authors: Jones Trevor A. , Detwiler Russell L.
Published: April 2019

We used a depth‐averaged reactive transport model to simulate transport of a supersaturated fluid through fractures and considered two models of precipitation‐induced surface alterations: (1) a localized 1‐D alteration of the surface and (2) a 3‐D alteration of the surface using the level‐set method. Comparing simulation results to a simple analytical solution for precipitation in a homogeneous (aperture and mineralogy) fracture demonstrated both models predict the alteration process reasonably well. However, comparing simulation results from both models to results from a recent experimental study of precipitation in a mineralogically heterogeneous fracture (Jones & Detwiler, 2016, https://doi.org/10.1002/2016GL069598) demonstrated that the ability of the 3‐D model to predict mineral growth across the aperture and in the fracture plane leads to much better agreement with the experimental observations. To quantify the role of reaction kinetics on the precipitation process, we ran additional simulations using the 3‐D evolution model for reaction rate constants ranging over 3 orders of magnitude. When the kinetics were much faster than the advective flux through the fracture, precipitation was focused near the inlet, which led to a transition from preferential flow near the inlet to more uniform flow near the outlet. When reaction kinetics were slow relative to advection, reaction sites grew uniformly throughout the fracture leading to the eventual formation of a single preferential flow path from inlet to outlet. Regardless of reaction rate, localization of precipitation reactions led to significant increases (3 to 20 times) in the time scale required to seal the fracture relative to a mineralogically homogeneous fracture.
A Curve‐Fitting Method for Estimating Bathymetry From Water Surface Height and Width
Authors: Schaperow Jacob R. , Li Dongyue , Margulis Steven A. , Lettenmaier Dennis P.
Published: April 2019

River discharge estimation requires knowledge of bathymetry. However, aside from a few locations where surveys have been conducted, bathymetric data are unavailable, even for major rivers. It has been suggested that water surface elevation and flow width measurements from the upcoming Surface Water and Ocean Topography (SWOT) satellite mission (planned launch 2021) may be used to infer the submerged channel geometry; however, the full potential of these measurements for inferring bathymetry has yet to be explored. We apply four different techniques, with varying assumptions about height‐width relationships, to predict unknown bathymetry. We call these “curve‐fitting methods” the linear, slope break, nonlinear, and nonlinear slope break (NLSB) methods. The linear and slope break methods are based on a linear height‐width relationship, while the nonlinear and NLSB methods are based on a height‐width relationship derived from hydraulic geometry equations. We generate SWOT‐like observations of height and width based on 5‐m gridded Upper Mississippi River data and evaluate the performance of each curve‐fitting method given the SWOT‐like observations. The NLSB method predicts bed elevation and low flow area with the least error, although the nonlinear method may be preferred in low data conditions. Additionally, we show that our method outperforms previously suggested methods, and we propose an NLSB‐based bathymetry prior for Bayesian discharge estimation algorithms.
Cross-linking dots on metal oxides
Authors: Ramachandran Roshini , Jung Dahee , Spokoyny Alexander M.
Published: April 2019

Metal oxides are ubiquitous in our daily lives because they are robust and possess versatile electrochemical properties. Despite their popularity, these materials present limitations with respect to effective large-scale implementation. Recently, there has been growing interest in creating hybrid metal oxides to tailor the morphology and properties of these materials. From this perspective, we highlight several recent developments in cross-linked hybrid metal oxides, focusing on chemical cross-linking techniques to enrich their properties. We discuss future directions of this cross-linking approach that could enable further manipulation of these materials.
Membrane-cytoskeletal crosstalk mediated by myosin-I regulates adhesion turnover during phagocytosis
Authors: Barger Sarah R. , Reilly Nicholas S. , Shutova Maria S. , Li Qingsen , Maiuri Paolo , Heddleston John M. , Mooseker Mark S. , Flavell Richard A. , Svitkina Tatyana , Oakes Patrick W. , Krendel Mira , Gauthier Nils C.
Published: April 2019

Phagocytosis of invading pathogens or cellular debris requires a dramatic change in cell shape driven by actin polymerization. For antibody-covered targets, phagocytosis is thought to proceed through the sequential engagement of Fc-receptors on the phagocyte with antibodies on the target surface, leading to the extension and closure of the phagocytic cup around the target. We find that two actin-dependent molecular motors, class 1 myosins myosin 1e and myosin 1f, are specifically localized to Fc-receptor adhesions and required for efficient phagocytosis of antibody-opsonized targets. Using primary macrophages lacking both myosin 1e and myosin 1f, we find that without the actin-membrane linkage mediated by these myosins, the organization of individual adhesions is compromised, leading to excessive actin polymerization, slower adhesion turnover, and deficient phagocytic internalization. This work identifies a role for class 1 myosins in coordinated adhesion turnover during phagocytosis and supports a mechanism involving membrane-cytoskeletal crosstalk for phagocytic cup closure.
Distinct G protein-coupled receptor phosphorylation motifs modulate arrestin affinity and activation and global conformation
Authors: Mayer Daniel , Damberger Fred F. , Samarasimhareddy Mamidi , Feldmueller Miki , Vuckovic Ziva , Flock Tilman , Bauer Brian , Mutt Eshita , Zosel Franziska , Allain Frédéric H. T. , Standfuss Jörg , Schertler Gebhard F. X. , Deupi Xavier , Sommer Martha E. , Hurevich Mattan , Friedler Assaf , Veprintsev Dmitry B.
Published: April 2019

Cellular functions of arrestins are determined in part by the pattern of phosphorylation on the G protein-coupled receptors (GPCRs) to which arrestins bind. Despite high-resolution structural data of arrestins bound to phosphorylated receptor C-termini, the functional role of each phosphorylation site remains obscure. Here, we employ a library of synthetic phosphopeptide analogues of the GPCR rhodopsin C-terminus and determine the ability of these peptides to bind and activate arrestins using a variety of biochemical and biophysical methods. We further characterize how these peptides modulate the conformation of arrestin-1 by nuclear magnetic resonance (NMR). Our results indicate different functional classes of phosphorylation sites: ‘key sites’ required for arrestin binding and activation, an ‘inhibitory site’ that abrogates arrestin binding, and ‘modulator sites’ that influence the global conformation of arrestin. These functional motifs allow a better understanding of how different GPCR phosphorylation patterns might control how arrestin functions in the cell.
How face perception unfolds over time
Authors: Dobs Katharina , Isik Leyla , Pantazis Dimitrios , Kanwisher Nancy
Published: April 2019

Within a fraction of a second of viewing a face, we have already determined its gender, age and identity. A full understanding of this remarkable feat will require a characterization of the computational steps it entails, along with the representations extracted at each. Here, we used magnetoencephalography (MEG) to measure the time course of neural responses to faces, thereby addressing two fundamental questions about how face processing unfolds over time. First, using representational similarity analysis, we found that facial gender and age information emerged before identity information, suggesting a coarse-to-fine processing of face dimensions. Second, identity and gender representations of familiar faces were enhanced very early on, suggesting that the behavioral benefit for familiar faces results from tuning of early feed-forward processing mechanisms. These findings start to reveal the time course of face processing in humans, and provide powerful new constraints on computational theories of face perception.
Simulations suggest a constrictive force is required for Gram-negative bacterial cell division
Authors: Nguyen Lam T. , Oikonomou Catherine M. , Ding H. Jane , Kaplan Mohammed , Yao Qing , Chang Yi-Wei , Beeby Morgan , Jensen Grant J.
Published: April 2019

To divide, Gram-negative bacterial cells must remodel cell wall at the division site. It remains debated, however, whether this cell wall remodeling alone can drive membrane constriction, or if a constrictive force from the tubulin homolog FtsZ is required. Previously, we constructed software (REMODELER 1) to simulate cell wall remodeling during growth. Here, we expanded this software to explore cell wall division (REMODELER 2). We found that simply organizing cell wall synthesis complexes at the midcell is not sufficient to cause invagination, even with the implementation of a make-before-break mechanism, in which new hoops of cell wall are made inside the existing hoops before bonds are cleaved. Division can occur, however, when a constrictive force brings the midcell into a compressed state before new hoops of relaxed cell wall are incorporated between existing hoops. Adding a make-before-break mechanism drives division with a smaller constrictive force sufficient to bring the midcell into a relaxed, but not necessarily compressed, state.
Controllable ion transport by surface-charged graphene oxide membrane
Authors: Zhang Mengchen , Guan Kecheng , Ji Yufan , Liu Gongping , Jin Wanqin , Xu Nanping
Published: April 2019

Ion transport is crucial for biological systems and membrane-based technology. Atomic-thick two-dimensional materials, especially graphene oxide (GO), have emerged as ideal building blocks for developing synthetic membranes for ion transport. However, the exclusion of small ions in a pressured filtration process remains a challenge for GO membranes. Here we report manipulation of membrane surface charge to control ion transport through GO membranes. The highly charged GO membrane surface repels high-valent co-ions owing to its high interaction energy barrier while concomitantly restraining permeation of electrostatically attracted low-valent counter-ions based on balancing overall solution charge. The deliberately regulated surface-charged GO membranes demonstrate remarkable enhancement of ion rejection with intrinsically high water permeance that exceeds the performance limits of state-of-the-art nanofiltration membranes. This facile and scalable surface charge control approach opens opportunities in selective ion transport for the fields of water transport, biomimetic ion channels and biosensors, ion batteries and energy conversions.
Dishevelled-3 conformation dynamics analyzed by FRET-based biosensors reveals a key role of casein kinase 1
Authors: Harnoš Jakub , Cañizal Maria Consuelo Alonso , Jurásek Miroslav , Kumar Jitender , Holler Cornelia , Schambony Alexandra , Hanáková Kateřina , Bernatík Ondřej , Zdráhal Zbyněk , Gömöryová Kristína , Gybeľ Tomáš , Radaszkiewicz Tomasz Witold , Kravec Marek , Trantírek Lukáš , Ryneš Jan , Dave Zankruti , Fernández-Llamazares Ana Iris , Vácha Robert , Tripsianes Konstantinos , Hoffmann Carsten , Bryja Vítězslav
Published: April 2019

Dishevelled (DVL) is the key component of the Wnt signaling pathway. Currently, DVL conformational dynamics under native conditions is unknown. To overcome this limitation, we develop the Fluorescein Arsenical Hairpin Binder- (FlAsH-) based FRET in vivo approach to study DVL conformation in living cells. Using this single-cell FRET approach, we demonstrate that (i) Wnt ligands induce open DVL conformation, (ii) DVL variants that are predominantly open, show more even subcellular localization and more efficient membrane recruitment by Frizzled (FZD) and (iii) Casein kinase 1 ɛ (CK1ɛ) has a key regulatory function in DVL conformational dynamics. In silico modeling and in vitro biophysical methods explain how CK1ɛ-specific phosphorylation events control DVL conformations via modulation of the PDZ domain and its interaction with DVL C-terminus. In summary, our study describes an experimental tool for DVL conformational sampling in living cells and elucidates the essential regulatory role of CK1ɛ in DVL conformational dynamics.
Femtosecond time synchronization of optical clocks off of a flying quadcopter
Authors: Bergeron Hugo , Sinclair Laura C. , Swann William C. , Khader Isaac , Cossel Kevin C. , Cermak Michael , Deschênes Jean-Daniel , Newbury Nathan R.
Published: April 2019

Future optical clock networks will require free-space optical time-frequency transfer between flying clocks. However, simple one-way or standard two-way time transfer between flying clocks will completely break down because of the time-of-flight variations and Doppler shifts associated with the strongly time-varying link distances. Here, we demonstrate an advanced, frequency comb-based optical two-way time-frequency transfer (O-TWTFT) that can successfully synchronize the optical timescales at two sites connected via a time-varying turbulent air path. The link between the two sites is established using either a quadcopter-mounted retroreflector or a swept delay line at speeds up to 24 ms−1. Despite 50-ps breakdown in time-of-flight reciprocity, the sites’ timescales are synchronized to < 1 fs in time deviation. The corresponding sites’ frequencies agree to ~ 10−18 despite 10−7 Doppler shifts. This work demonstrates comb-based O-TWTFT can enable free-space optical networks between airborne or satellite-borne optical clocks for precision navigation, timing and probes of fundamental science.
Publisher Correction: A network of chaperones prevents and detects failures in membrane protein lipid bilayer integration
Authors: Coelho João P. L. , Stahl Matthias , Bloemeke Nicolas , Meighen-Berger Kevin , Alvira Carlos Piedrafita , Zhang Zai-Rong , Sieber Stephan A. , Feige Matthias J.
Published: April 2019

The original version of this Article contained errors in Fig. 1 and Supplementary Fig. 3. In Fig. 1, the labels indicating the Cx32wt constructs in panels d and e were incorrectly shifted with respect to the relevant western blot lanes. In Supplementary Fig. 3, numbers of unique peptides and % sequence coverage were incorrectly reported as being for wt and L90H separately, and should refer to wt and L90H combined. These errors have been corrected in the PDF and HTML versions of the Article.
Machine-learned multi-system surrogate models for materials prediction
Authors: Nyshadham Chandramouli , Rupp Matthias , Bekker Brayden , Shapeev Alexander V. , Mueller Tim , Rosenbrock Conrad W. , Csányi Gábor , Wingate David W. , Hart Gus L. W.
Published: April 2019

Surrogate machine-learning models are transforming computational materials science by predicting properties of materials with the accuracy of ab initio methods at a fraction of the computational cost. We demonstrate surrogate models that simultaneously interpolate energies of different materials on a dataset of 10 binary alloys (AgCu, AlFe, AlMg, AlNi, AlTi, CoNi, CuFe, CuNi, FeV, and NbNi) with 10 different species and all possible fcc, bcc, and hcp structures up to eight atoms in the unit cell, 15,950 structures in total. We find that the deviation of prediction errors when increasing the number of simultaneously modeled alloys is <1 meV/atom. Several state-of-the-art materials representations and learning algorithms were found to qualitatively agree on the prediction errors of formation enthalpy with relative errors of <2.5% for all systems.
Control of electrical conductivity of highly stacked zinc oxide nanocrystals by ultraviolet treatment
Authors: Han Wooje , Kim Jiwan , Park Hyung-Ho
Published: April 2019

Zinc oxide (ZnO) nanocrystals (NCs) were synthesized using a modified sol-gel method. Ultraviolet (UV) treatment was performed under various atmospheres on the highly stacked ZnO NCs. The prepared NCs were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, photoluminescence spectroscopy, and atomic force microscopy to investigate their structural, electrical, and electrochemical properties. Through these analyses, the effect of the UV treatment on the chemical and electrical characteristics of ZnO NCs was established. According to the analyses, the organic ligands in the NCs were decomposed, and the particles were densified. The mobility of UV-treated ZnO NCs thin films increased to 1.4 cm2/Vs, almost 2 orders higher than the UV untreated ZnO thin films. It was confirmed that the recombination from oxygen vacancies of ZnO could be controlled by UV irradiation. As decreased oxygen vacancies, the band gap of ZnO NCs was increased from 3.2 eV to 3.27 eV.
Author Correction: Nucleus-specific X-ray stain for 3D virtual histology
Authors: Müller Mark , Kimm Melanie A. , Ferstl Simone , Allner Sebastian , Achterhold Klaus , Herzen Julia , Pfeiffer Franz , Busse Madleen
Published: April 2019

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
Cell-penetrating peptide sequence and modification dependent uptake and subcellular distribution of green florescent protein in different cell lines
Authors: Patel Sanjay G. , Sayers Edward J. , He Lin , Narayan Rohan , Williams Thomas L. , Mills Emily M. , Allemann Rudolf K. , Luk Louis Y. P. , Jones Arwyn T. , Tsai Yu-Hsuan
Published: April 2019

Protein therapy holds great promise for treating a variety of diseases. To act on intracellular targets, therapeutic proteins must cross the plasma membrane. This has previously been achieved by covalent attachment to a variety of cell-penetrating peptides (CPPs). However, there is limited information on the relative performance of CPPs in delivering proteins to cells, specifically the cytosol and other intracellular locations. Here we use green fluorescent protein (GFP) as a model cargo to compare delivery capacity of five CPP sequences (Penetratin, R8, TAT, Transportan, Xentry) and cyclic derivatives in different human cell lines (HeLa, HEK, 10T1/2, HepG2) representing different tissues. Confocal microscopy analysis indicates that most fusion proteins when incubated with cells at 10 µM localise to endosomes. Quantification of cellular uptake by flow cytometry reveals that uptake depends on both cell type (10T1/2 > HepG2 > HeLa > HEK), and CPP sequence (Transportan > R8 > Penetratin≈TAT > Xentry). CPP sequence cyclisation or addition of a HA-sequence increased cellular uptake, but fluorescence was still contained in vesicles with no evidence of endosomal escape. Our results provide a guide to select CPP for endosomal/lysosomal delivery and a basis for developing more efficient CPPs in the future.