Development of a Numerical Model to Analyze the Formation and Development Process of River Mouth Bars

An integrated sediment management approach that includes the recovery of the amount of declined sediment supply is effective as a fundamental solution to coastal erosion. During planning, it is essential to analyze the transfer mechanism of the sediments generated from estuaries (the junction between a river and sea) to assess the amount and rate of sediment discharge (from the river to sea) supplied back to the coast. Although numerical models that interpret the tidal sand bar flushing process during flooding have been studied, thus far, there has been no study focusing on the formation and development processes of tidal sand bars. Therefore, this study aims to construct wave deformation, flow regime calculation, and topographic change analysis models to assess the amount of recovered sediment discharge and reproduce the tidal sand bar formation process through numerical analysis for integrated littoral drift management. The tidal sand bar formation process was simulated, and the wave energy and duration of action concepts were implemented to predict the long-term littoral movement. The river flux and wave conditions during winter when tidal sand bars dominantly develop were considered as the external force conditions required for calculation. The initial condition of the topographic data directly after the Maeupcheon tidal sand bar flushing during flooding was set as the initial topography. Consequently, the tidal sand bar formation and development due to nearshore currents dependent on the incident wave direction were reproduced. Approximately 66 h after the initial topography, a sand bar formation was observed at the Maengbang estuary.

Evaluation of Intra-Articular Injection of Bevacizumab on the Prevention of Physeal Bar Formation in Type 4 Salter Harris Model in Rats: A Pilot Study

Background: This study was designed to achieve a new method as a preventive treatment for complications of growth plate fractures. In this study, we investigate the effect of intra-articular injection of anti-vascular endothelial growth factor (anti-VEGF) antibody bevacizumab on the repair process of articular cartilage in a type 4 Salter Harris injury model. Methods: A Salter Harris injury was created on the proximal tibial growth plate of 14 rats by a 1.8 mm drill. The rats were randomly classified into two groups: group LD, administration of high-dose intra-articular injection of bevacizumab (250 μg), and group HD, administration of low-dose intra-articular injection of bevacizumab (50 μg) after injury. The rats were killed 2 months postoperatively and their tibia underwent micro-computed tomography (CT) analysis, histological assessment, and measurement of tibial bone length. Results: Bony bar formation was observed in 71% of the samples in the high-dose group and in 100% of the low-dose group. Relative increase in physeal cartilage thickness (P = 0.007) and decrease in bony bar formation (P = 0.029) were observed significantly in the high dose group. There was no significant difference in tibia length between the two groups (P = 0.150). Conclusion: Intra-articular administration of bevacizumab demonstrated positive restorative effects. We suggest this method of treatment due to its potential of improving cartilage repair and capability to be used as a main or adjacent treatment in osteochondral defects.

A Lopsided Outer Solar System?

Axisymmetric disks of eccentric orbits in near-Keplerian potentials are unstable and undergo exponential growth in inclination. Recently, Zderic et al. showed that an idealized disk then saturates to a lopsided mode. Here we show, using N-body simulations, that this apsidal clustering also occurs in a primordial Scattered Disk in the outer solar system, which includes the orbit-averaged gravitational influence of the giant planets. We explain the dynamics using Lynden-Bell's mechanism for bar formation in galaxies. We also show surface density and line-of-sight velocity plots at different times during the instability, highlighting the formation of concentric circles and spiral arms in velocity space.

Stepan Borysenok: to the Portrait of the Scientist

The history of the law in the Grand Duchy of Lithuania has always attracted the attention of researchers. The productive period in its study was the activity of the Commission for the Study of the History of Western-Ruthenian and Ukrainian Law of All-Ukrainian Academy of Sciences (hereafter AUAS). The theoretical achievements of the commission are significant. Nowadays some of its members’ works have been republished with modern commentaries, and separate studies have been devoted to them. But there are such members whose works do not have any historiographical researches despite their great scientific achievements. One of them is the historian Stefan (Stepan) Hnatovych Borysenok (May 17, 1891 – November 14, 1937). Borysenok was a talented and extraordinary researcher. This article presents his biographical data as well as the theoretical achievements of the scientist are analyzed. The scientific achievements of the researcher in the field of law history are not very large. They are about 10 works (thorough scientific articles) and several reviews. They were significant for that time. However a few decades later after writing of these articles modern researchers point to a significant number of inaccuracies and errors in his works. S. Borysenok’s works were highly appreciated by his contemporaries and scientific mentors M. Vasylenko and O. Malynovsky. First of all they were impressed by the fact that he always tried to turn to primary sources and was critical to the works of his predecessors. His works show an excellent knowledge of the historiography of a particular research problem. In addition S. Borysenok being a lawyer by education was able to analyze in more details the certain problems that were not always clear to historians. The issues related to the First Lithuanian Statute and the history of the Bar in the Grand Duchy of Lithuania had been researched by S. Borysenok since the middle of 1920s. In particular the main subject of his research in Moscow archives was "History of the Bar in Ukraine in the 16th–18th Centuries. The special articles of the researcher are interesting and original. Among them are such articles as "Formation of a Professional Bar in the Lithuanian-Ruthenian State", "Lawyer's Fee in the Lithuanian Principality in the 16th–17th Centuries" (The latter was published in the 7th issue of the "Proceedings of the Commission for the Study of the History of Western-Ruthenian and Ukrainian Law". But that issue was destroyed). One of the greatest work by S. Borysenok concerns the history of the Bar formation in the first half of the 16th century. Also in the late 1920's the researcher had been preparing for publication a thorough work with focus on the Lithuanian Statute (history of drafting the code, sources, lists). Correspondence with Lithuanian researcher A. Janulaitis (the ancestor of the Lithuanian Statutes historiography) indicates that the manuscript of this work (or a significant part of it) probably existed. At the same time the facts of cooperation with Lithuanian historians are recorded and they give us the opportunity to hope that the lost achievements of the researcher can still be found and introduced into scientific circulation. And we are convinced that they will be the impetus for the new scientific research and will cause a significant number of scientific discussions. In the early 1930's S. Borysenok was an employee at the library. He actively worked at the acquisition of the library fund with foreign professional publications. He tried to establish and systematize international exchange. On September 23, 1937 S. Borysenok was arrested on trumped up charges of alleged involvement in an "anti-Soviet nationalist organization". On October 25 of the same year he was sentenced to death via shooting (executed on November, 14).

Thyroid hormones regulate the formation and environmental plasticity of white bars in clownfishes

Determining how plasticity of developmental traits responds to environmental conditions is a challenge that must combine evolutionary sciences, ecology, and developmental biology. During metamorphosis, fish alter their morphology and color pattern according to environmental cues. We observed that juvenile clownfish (Amphiprion percula) modulate the developmental timing of their adult white bar formation during metamorphosis depending on the sea anemone species in which they are recruited. We observed an earlier formation of white bars when clownfish developed with Stichodactyla gigantea (Sg) than with Heteractis magnifica (Hm). As these bars, composed of iridophores, form during metamorphosis, we hypothesized that timing of their development may be thyroid hormone (TH) dependent. We treated clownfish larvae with TH and found that white bars developed earlier than in control fish. We further observed higher TH levels, associated with rapid white bar formation, in juveniles recruited in Sg than in Hm, explaining the faster white bar formation. Transcriptomic analysis of Sg recruits revealed higher expression of duox, a dual oxidase implicated in TH production as compared to Hm recruits. Finally, we showed that duox is an essential regulator of iridophore pattern timing in zebrafish. Taken together, our results suggest that TH controls the timing of adult color pattern formation and that shifts in duox expression and TH levels are associated with ecological differences resulting in divergent ontogenetic trajectories in color pattern development.

Modeling of Spiral Structure in a Multi-Component Milky Way-Like Galaxy

Using recent observational data, we construct a set of multi-component equilibrium models of the disk of a Milky Way-like galaxy. The disk dynamics are studied using collisionless-gaseous numerical simulations, based on the joined integration of the equations of motion for the collision-less particles using direct integration of gravitational interaction and the gaseous SPH-particles. We find that after approximately one Gyr, a prominent central bar is formed having a semi-axis length of about three kpc, together with a multi-armed spiral pattern represented by a superposition of m= 2-, 3-, and 4-armed spirals. The spiral structure and the bar exist for at least 3 Gyr in our simulations. The existence of the Milky Way bar imposes limitations on the density distributions in the subsystems of the Milky Way galaxy. We find that a bar does not form if the radial scale length of the density distribution in the disk exceeds 2.6 kpc. As expected, the bar formation is also suppressed by a compact massive stellar bulge. We also demonstrate that the maximum value in the rotation curve of the disk of the Milky Way galaxy, as found in its central regions, is explained by non-circular motion due to the presence of a bar and its orientation relative to an observer.

A Quantitative Study of Hydraulic Parameters of Thamirabarani River

Each channel has unique characteristics of its own; River Thamirabarani being no exception. The project proposal aims at investigating the hydraulic geometry of the Thamirabarani River from Pothigai to the downstream up to Srivaikundam [1]. The interrelationship among stream sediment load, channel width and channel depth shows the nature of hydraulic geometry of Thamirabarani River channel. Due to the effect of Papanasam dam the natural flow of this river has been obstructed, and this is resulting in reduced discharge at downstream [2]. Confluences of major tributaries such as Manimuthar, Servalaru, Gadana and Ramanadhi may play significant role for the influx of extra discharge and sediment load to the main river. This extra sediment influx is also responsible for frequent bar formation in the river channel. The input morphometric maps have to be prepared using GIS and Remote Sensing tools like Arc GIS 10.1 and Global Mapper [3].

Bars formed in galaxy merging and their classification with deep learning

Context. Stellar bars are a common morphological feature of spiral galaxies. While it is known that they can form in isolation, or be induced tidally, few studies have explored the production of stellar bars in galaxy merging. We look to investigate bar formation in galaxy merging using methods from deep learning to analyse our N-body simulations. Aims. The primary aim is to determine the constraints on the mass ratio and orientations of merging galaxies that are most conducive to bar formation. We further aim to explore whether it is possible to classify simulated barred spiral galaxies based on the mechanism of their formation. We test the feasibility of this new classification schema with simulated galaxies. Methods. Using a set of 29 400 images obtained from our simulations, we first trained a convolutional neural network to distinguish between barred and non-barred galaxies. We then tested the network on simulations with different mass ratios and spin angles. We adapted the core neural network architecture for use with our additional aims. Results. We find that a strong inverse relationship exists between the mass ratio and the number of bars produced. We also identify two distinct phases in the bar formation process; (1) the initial, tidally induced formation pre-merger and (2) the destruction and/or regeneration of the bar during and after the merger. Conclusions. Mergers with low mass ratios and closely-aligned orientations are considerably more conducive to bar formation compared to equal-mass mergers. We demonstrate the flexibility of our deep learning approach by showing it is feasible to classify bars based on their formation mechanism.