Unraveling Interactions between Asymmetric Tidal Turbulence, Residual Circulation, and Salinity Dynamics in Short, Periodically Weakly Stratified Estuaries

AbstractAsymmetric tidal turbulence (ATT) strongly influences estuarine health and functioning. However, its impact on the three-dimensional estuarine dynamics and the feedback of water motion and salinity distribution on ATT remain poorly understood, especially for short estuaries (estuarine length ≪ tidal wavelength). This study systematically investigates the abovementioned interactions in a short estuary for the first time, considering periodically weakly stratified conditions. This is done by developing a three-dimensional semi-analytical model (combining perturbation method with finite element method) that allows a dissection of the contributions of different processes to ATT, estuarine circulation, and salt transport. The generation of ATT is dominated by (i) strain-induced periodic stratification and (ii) asymmetric bottom-shear-generated turbulence, and their contributions to ATT are different both in amplitude and phase. The magnitude of the residual circulation related to ATT and the eddy viscosity–shear covariance (ESCO) is about half of that of the gravitational circulation (GC) and shows a “reversed” pattern as compared to GC. ATT generated by strain-induced periodic stratification contributes to an ESCO circulation with a spatial structure similar to GC. This circulation reduces the longitudinal salinity gradients and thus weakens GC. Contrastingly, the ESCO circulation due to asymmetric bottom-shear-generated turbulence shows patterns opposite to GC and acts to enhance GC. Concerning the salinity dynamics at steady state, GC and tidal pumping are equally important to salt import, whereas ESCO circulation yields a significant seaward salt transport. These findings highlight the importance of identifying the sources of ATT to understand its impact on estuarine circulation and salt distribution.

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Three-Dimensional Salt Dynamics in Well-Mixed Estuaries: Influence of Estuarine Convergence, Coriolis, and Bathymetry

Journal of Physical Oceanography ◽

10.1175/jpo-d-16-0247.1 ◽

2017 ◽

Vol 47 (7) ◽

pp. 1843-1871 ◽

Cited By ~ 5

Author(s):

Xiaoyan Wei ◽

Mohit Kumar ◽

Henk M. Schuttelaars

Keyword(s):

Coriolis Force ◽

Three Dimensional ◽

Temporal Correlation ◽

Salt Transport ◽

Residual Circulation ◽

Three Dimensional Model ◽

Coriolis Effects ◽

Set Up ◽

The Right ◽

The Impact

AbstractA semianalytical three-dimensional model is set up to dynamically calculate the coupled water motion and salinity for idealized well-mixed estuaries and prognostically investigate the influence of each physical mechanism on the residual salt transport. As a study case, a schematized estuary with an exponentially converging width and a channel–shoal structure is considered. The temporal correlation between horizontal tidal velocities and tidal salinities is the dominant process for the landward residual salt transport. The residual salt transport induced by residual circulation is locally significant, but the induced salt transport integrated over the cross section is small. The impacts of the estuarine geometry, Coriolis force, and bathymetry on the salt dynamics are studied using three dedicated experiments, in which the impact of each of these factors is studied separately. To assess the impact of width convergence, a convergent estuary without bathymetric variations or Coriolis force is considered. In this experiment, the temporal correlation between tidal velocities and salinities is the only landward salt transport process. In the second experiment, Coriolis effects are included. This results in a significant residual salt transport cell due to the advection of the tidally averaged salinity by residual circulation, with salt imported into the estuary from the left side and exported on the right (looking seaward). In the last experiment, a lateral channel–shoal structure is included while the Coriolis effects are excluded. This results in a significant landward salt transport through the deeper channel and a seaward salt transport over the shoals due to the advection of the tidally averaged salinity by residual circulation.

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Cobalt-based magnetic Weyl semimetals with high-thermodynamic stabilities

npj Computational Materials ◽

10.1038/s41524-020-00461-w ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Wei Luo ◽

Yuma Nakamura ◽

Jinseon Park ◽

Mina Yoon

Keyword(s):

Tight Binding ◽

Three Dimensional ◽

Interlayer Coupling ◽

First Principles Calculation ◽

Optimization Approach ◽

Binding Model ◽

Nodal Lines ◽

Weyl Semimetal ◽

Topological Quantum ◽

First Time

AbstractRecent experiments identified Co3Sn2S2 as the first magnetic Weyl semimetal (MWSM). Using first-principles calculation with a global optimization approach, we explore the structural stabilities and topological electronic properties of cobalt (Co)-based shandite and alloys, Co3MM’X2 (M/M’ = Ge, Sn, Pb, X = S, Se, Te), and identify stable structures with different Weyl phases. Using a tight-binding model, for the first time, we reveal that the physical origin of the nodal lines of a Co-based shandite structure is the interlayer coupling between Co atoms in different Kagome layers, while the number of Weyl points and their types are mainly governed by the interaction between Co and the metal atoms, Sn, Ge, and Pb. The Co3SnPbS2 alloy exhibits two distinguished topological phases, depending on the relative positions of the Sn and Pb atoms: a three-dimensional quantum anomalous Hall metal, and a MWSM phase with anomalous Hall conductivity (~1290 Ω−1 cm−1) that is larger than that of Co2Sn2S2. Our work reveals the physical mechanism of the origination of Weyl fermions in Co-based shandite structures and proposes topological quantum states with high thermal stability.

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Shell-crossing in a ΛCDM Universe

Monthly Notices of the Royal Astronomical Society Letters ◽

10.1093/mnrasl/slaa198 ◽

2020 ◽

Vol 501 (1) ◽

pp. L71-L75

Author(s):

Cornelius Rampf ◽

Oliver Hahn

Keyword(s):

Dark Matter ◽

Perturbation Theory ◽

Large Scale ◽

Cold Dark Matter ◽

Three Dimensional ◽

Random Initial Data ◽

Recursion Relations ◽

Indispensable Tool ◽

First Time ◽

Very High

ABSTRACT Perturbation theory is an indispensable tool for studying the cosmic large-scale structure, and establishing its limits is therefore of utmost importance. One crucial limitation of perturbation theory is shell-crossing, which is the instance when cold-dark-matter trajectories intersect for the first time. We investigate Lagrangian perturbation theory (LPT) at very high orders in the vicinity of the first shell-crossing for random initial data in a realistic three-dimensional Universe. For this, we have numerically implemented the all-order recursion relations for the matter trajectories, from which the convergence of the LPT series at shell-crossing is established. Convergence studies performed at large orders reveal the nature of the convergence-limiting singularities. These singularities are not the well-known density singularities at shell-crossing but occur at later times when LPT already ceased to provide physically meaningful results.

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Imaging the Human Thyroid Using Three-Dimensional Diffuse Optical Tomography: A Preliminary Study

Applied Sciences ◽

10.3390/app11041670 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1670

Author(s):

Tetsuya Mimura ◽

Shinpei Okawa ◽

Hiroshi Kawaguchi ◽

Yukari Tanikawa ◽

Yoko Hoshi

Keyword(s):

Optical Tomography ◽

Tumor Hypoxia ◽

Three Dimensional ◽

Diffuse Optical Tomography ◽

Element Model ◽

Needle Aspiration ◽

Human Thyroid ◽

Tissue Oxygen Saturation ◽

Preliminary Study ◽

First Time

Thyroid cancer is usually diagnosed by ultrasound imaging and fine-needle aspiration biopsy. However, diagnosis of follicular thyroid carcinomas (FTC) is difficult because FTC lacks nuclear atypia and a consensus on histological interpretation. Diffuse optical tomography (DOT) offers the potential to diagnose FTC because it can measure tumor hypoxia, while image reconstruction of the thyroid is still challenging mainly due to the complex anatomical features of the neck. In this study, we attempted to solve this issue by creating a finite element model of the human neck excluding the trachea (a void region). By reconstruction of the absorption coefficients at three wavelengths, 3D tissue oxygen saturation maps of the human thyroid are obtained for the first time by DOT.

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The on-axis magnetic well and Mercier's criterion for arbitrary stellarator geometries

Journal of Plasma Physics ◽

10.1017/s0022377821000465 ◽

2021 ◽

Vol 87 (2) ◽

Author(s):

P. Kim ◽

R. Jorge ◽

W. Dorland

Keyword(s):

Magnetic Field ◽

Original Work ◽

Three Dimensional ◽

Radial Distance ◽

Analytical Form ◽

One Dimensional ◽

Modern Notation ◽

Magnetic Well ◽

First Time ◽

Dimensional Integral

A simplified analytical form of the on-axis magnetic well and Mercier's criterion for interchange instabilities for arbitrary three-dimensional magnetic field geometries is derived. For this purpose, a near-axis expansion based on a direct coordinate approach is used by expressing the toroidal magnetic flux in terms of powers of the radial distance to the magnetic axis. For the first time, the magnetic well and Mercier's criterion are then written as a one-dimensional integral with respect to the axis arclength. When compared with the original work of Mercier, the derivation here is presented using modern notation and in a more streamlined manner that highlights essential steps. Finally, these expressions are verified numerically using several quasisymmetric and non-quasisymmetric stellarator configurations including Wendelstein 7-X.

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Towards an Improved Model of the Galaxy

Highlights of Astronomy ◽

10.1017/s1539299600022280 ◽

1998 ◽

Vol 11 (1) ◽

pp. 570-570

Author(s):

Johan Holmberg ◽

Lennart Lindegren ◽

Chris Flynn

Keyword(s):

Three Dimensional ◽

Direct Determination ◽

Galactic Structure ◽

Open Clusters ◽

Selection Effects ◽

Observational Errors ◽

Red Giant ◽

Improved Model ◽

First Time ◽

Hr Diagram

We use the Hipparcos survey to derive an improved model of the local galactic structure. The availability of parallaxes for all the stars permits direct determination of stellar distributions, eliminating the basic indeterminacy of classical methods based on star counts. Hipparcos gives for the first time a truly three-dimensional view of the solar vicinity, and a complete, homogeneous and highly accurate set of magnitudes and colours. This means that new techniques can be applied in the treatment of the data which place strong constraints on a model that tries to describe the local Galactic structure. Here we investigate how well a static model of low complexitycan describe the Hipparcos observations. The interpretation of the Hipparcos data is complicated by various observational errors and selection effects that are hard to treat correctly. We do not try to correct the data, but instead use a model and subject this model to the same observational errors and selection effects. A model catalogue is created that can be compared with the observed catalogue directly in the observational domain, thereby eliminating the effects from various biases. Many features in the HR diagram are for the first time seen in field stars thanks to Hipparcos, such as the slanted red giant clump, previously seen in rich old open clusters such as Berkeley 18. This and other features ofthe observed HR diagram are well reproduced by the model thanks to the rather detailed modelling of the joint Mv/B — V distribution. Actually, separate distributions were derived for the three different components, disk, thick disk and halo, using the kinematic characteristics of the components to discriminate between them.

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A New Category of Three-Dimensional Chaotic Flows with Identical Eigenvalues

International Journal of Bifurcation and Chaos ◽

10.1142/s0218127420500261 ◽

2020 ◽

Vol 30 (02) ◽

pp. 2050026 ◽

Cited By ~ 1

Author(s):

Zahra Faghani ◽

Fahimeh Nazarimehr ◽

Sajad Jafari ◽

Julien C. Sprott

Keyword(s):

Chaotic Systems ◽

Autonomous Systems ◽

Three Dimensional ◽

Special Property ◽

Computer Search ◽

Chaotic Flows ◽

Stable Equilibria ◽

Dynamical Properties ◽

Simple Systems ◽

First Time

In this paper, some new three-dimensional chaotic systems are proposed. The special property of these autonomous systems is their identical eigenvalues. The systems are designed based on the general form of quadratic jerk systems with 10 terms, and some systems with stable equilibria. Using a systematic computer search, 12 simple chaotic systems with identical eigenvalues were found. We believe that systems with identical eigenvalues are described here for the first time. These simple systems are listed in this paper, and their dynamical properties are investigated.

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Structure of the Lectin Mannose 6-Phosphate Receptor Homology (MRH) Domain of Glucosidase II, an Enzyme That Regulates Glycoprotein Folding Quality Control in the Endoplasmic Reticulum

Journal of Biological Chemistry ◽

10.1074/jbc.m113.450239 ◽

2013 ◽

Vol 288 (23) ◽

pp. 16460-16475 ◽

Cited By ~ 21

Author(s):

Linda J. Olson ◽

Ramiro Orsi ◽

Solana G. Alculumbre ◽

Francis C. Peterson ◽

Ivan D. Stigliano ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Three Dimensional ◽

Binding Pocket ◽

Dimensional Structure ◽

Mannose Residue ◽

Glucosidase Ii ◽

Mannose 6 Phosphate ◽

First Time ◽

Conserved Residue

Here we report for the first time the three-dimensional structure of a mannose 6-phosphate receptor homology (MRH) domain present in a protein with enzymatic activity, glucosidase II (GII). GII is involved in glycoprotein folding in the endoplasmic reticulum. GII removes the two innermost glucose residues from the Glc3Man9GlcNAc2 transferred to nascent proteins and the glucose added by UDP-Glc:glycoprotein glucosyltransferase. GII is composed of a catalytic GIIα subunit and a regulatory GIIβ subunit. GIIβ participates in the endoplasmic reticulum localization of GIIα and mediates in vivo enhancement of N-glycan trimming by GII through its C-terminal MRH domain. We determined the structure of a functional GIIβ MRH domain by NMR spectroscopy. It adopts a β-barrel fold similar to that of other MRH domains, but its binding pocket is the most shallow known to date as it accommodates a single mannose residue. In addition, we identified a conserved residue outside the binding pocket (Trp-409) present in GIIβ but not in other MRHs that influences GII glucose trimming activity.

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Impact of the Depth-to-Width Ratio of Periodically Stratified Tidal Channels on the Estuarine Circulation

Journal of Physical Oceanography ◽

10.1175/jpo-d-14-0084.1 ◽

2015 ◽

Vol 45 (8) ◽

pp. 2048-2069 ◽

Cited By ~ 17

Author(s):

Elisabeth Schulz ◽

Henk M. Schuttelaars ◽

Ulf Gräwe ◽

Hans Burchard

Keyword(s):

Eddy Viscosity ◽

Transport Model ◽

Stable Stratification ◽

Estuarine Circulation ◽

Width Ratio ◽

Cross Sectional ◽

Tidal Straining ◽

The Individual ◽

Periodic Stratification ◽

The Impact

AbstractThe dependency of the estuarine circulation on the depth-to-width ratio of a periodically, weakly stratified tidal estuary is systematically investigated here for the first time. Currents, salinity, and other properties are simulated by means of the General Estuarine Transport Model (GETM) in cross-sectional slice mode, applying a symmetric Gaussian-shaped depth profile. The width is varied over four orders of magnitude. The individual along-channel circulation contributions from tidal straining, gravitation, advection, etc., are calculated and the impact of the depth-to-width ratio on their intensity is presented and elucidated. It is found that the estuarine circulation exhibits a distinct maximum in medium-wide channels (intermediate depth-to-width ratio depending on various parameters), which is caused by a maximum of the tidal straining contribution. This maximum is related to a strong tidal asymmetry of eddy viscosity and shear created by secondary strain-induced periodic stratification (2SIPS): in medium channels, transverse circulation generated by lateral density gradients due to laterally differential longitudinal advection induces stable stratification at the end of the flood phase, which is further increased during ebb by longitudinal straining (SIPS). Thus, eddy viscosity is low and shear is strong in the entire ebb phase. During flood, SIPS decreases the stratification so that eddy viscosity is high and shear is weak. The circulation resulting from this viscosity–shear correlation, the tidal straining circulation, is oriented like the classical, gravitational circulation, with riverine outflow at the surface and oceanic inflow close to the bottom. In medium channels, it is about 5 times as strong as in wide (quasi one-dimensional) channels, in which 2SIPS is negligible.

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Diagnosis of COVID-19 using 3D CT scans and vaccination for COVID-19

World Journal of Engineering ◽

10.1108/wje-03-2021-0161 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Gangadhar Ch ◽

S. Jana ◽

Sankararao Majji ◽

Prathyusha Kuncha ◽

Fantin Irudaya Raj E. ◽

...

Keyword(s):

Virus Isolate ◽

Research Work ◽

Three Dimensional ◽

Ct Scans ◽

Data Sets ◽

Content Type ◽

Infected People ◽

3D Data ◽

Ct Classification ◽

First Time

Purpose For the first time in a decade, a new form of pneumonia virus, coronavirus, COVID-19, appeared in Wuhan, China. To date, it has affected millions of people, killed thousands and resulted in thousands of deaths around the world. To stop the spread of this virus, isolate the infected people. Computed tomography (CT) imaging is very accurate in revealing the details of the lungs and allows oncologists to detect COVID. However, the analysis of CT scans, which can include hundreds of images, may cause delays in hospitals. The use of artificial intelligence (AI) in radiology could help to COVID-19-positive cancer in this manner is the main purpose of the work. Design/methodology/approach CT scans are a medical imaging procedure that gives a three-dimensional (3D) representation of the lungs for clinical purposes. The volumetric 3D data sets can be regarded as axial, coronal and transverse data sets. By using AI, we can diagnose the virus presence. Findings The paper discusses the use of an AI for COVID-19, and CT classification issue and vaccination details of COVID-19 have been detailed in this paper. Originality/value Originality of the work is, all the data can be collected genuinely and did research work doneown methodology.

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