Hyperbolic self-gravity solver for large scale hydrodynamical simulations

A new computationally efficient method has been introduced to treat self-gravity in Eulerian hydrodynamical simulations. It is applied simply by modifying the Poisson equation into an inhomogeneous wave equation. This roughly corresponds to the weak field limit of the Einstein equations in general relativity, and as long as the gravitation propagation speed is taken to be larger than the hydrodynamical characteristic speed, the results agree with solutions for the Poisson equation. The solutions almost perfectly agree if the domain is taken large enough, or appropriate boundary conditions are given. Our new method cannot only significantly reduce the computational time compared with existent methods, but is also fully compatible with massive parallel computation, nested grids, and adaptive mesh refinement techniques, all of which can accelerate the progress in computational astrophysics and cosmology

A Study of Spatial Perception in Virtual Space via Display and the Intervention Effects of Haptic Feedback

Okada K., Matsui K., Atsuumi K., et al. A Study of Spatial Perception in Virtual Space via Display and the Intervention Effects of Haptic Feedback. IEEE Access 12, 90124 (2024); https://doi.org/10.1109/ACCESS.2024.3420724.In recent years, technologies for presenting users with virtual spaces have been rapidly developing. Some applications allow users to observe three-dimensional spaces via screens and influence those virtual spaces using certain devices. In such cases, it is necessary not only to rely on the presentation of depth information but also to adapt to depth in the virtual space to completely execute tasks. In this study, we investigated the spatial perception characteristics of commonly used two-dimensional (2D) displays and advanced spatial reality (SR) displays with spatial presentation capabilities. The research participants performed tasks of tracing a trajectory on a wall surface that changes angles in a three-dimensional virtual space. In addition, we examined the effect of haptic feedback intervention on spatial perception during task execution and its persistence. For 2D displays, we realized that haptic feedback improves task accuracy and that the effect persists even after the feedback is removed. However, this applied only to tasks under feedback conditions, and no broad effect on spatial perception was observed. By contrast, for SR displays, we realized that haptic feedback may have a detrimental effect on spatial perception. Moreover, we quantitatively proved that the use of SR displays improves spatial perception accuracy compared with 2D displays and that the relationship between the line of sight and display angle is critical for spatial perception. In conclusion, the following two points are inferred from this study. (1) To improve spatial perception, it is necessary to consider methods that directly intervene in the body schema and the peripersonal space in the future. (2) Feedback by multiple modalities is not necessarily effective in presenting information on virtual space and obtaining spatial perception

Pyoderma gangrenosum after breast cancer resection: A less-invasive and early treatment using the skin around ulcers

Surgical invasion is a risk factor of pyoderma gangrenosum (PG). A total of 25% of postoperative PG cases were reported to occur after breast surgeries, including bilateral breast reduction and breast reconstruction following cancer resection. Immunosuppressive therapy and less-invasive wound therapy are necessary; however, the complete healing of ulcers takes 5.1 months on average. We herein report a case of skin grafting under a surgical concept of less-invasive and short-term treatment. An 82-year-old woman complained of a high fever and severe pain at her breast wounds after bilateral breast cancer resection. Although we performed emergency debridement surgery to remove the necrotic tissue, suspecting surgical site infection and inflammation, her high fever persisted. She was diagnosed with PG because of the physical findings of characteristic painful, sterile ulcerations, bullae and pustules, and the pathological abundance of neutrophils in the absence of infection and vasculitis. Oral administration of prednisolone 30 mg/day improved the symptoms, and we applied negative-pressure wound therapy (NPWT) from day 16 following debridement surgery. After the gradual reduction of oral steroid intake to 12.5 mg/day, we performed skin grafting surgery. To limit the surgical invasion, we used the surplus skin around the ulcers. Split-thickness mesh skin grafts were fixed by NPWT to avoid the use of tie-over sutures. We achieved short-term treatment of PG with a less-invasive surgical strategy using skin around the ulcers and NPWT

A quantitative comparison of fish assemblage between amacroalgae bed and an adjoining sandy beach in the central Seto Inland Sea

植生の有無が魚類群集に与える影響を明らかにすることを目的として，瀬戸内海中央部の無人島（小久野島）の東岸において隣接するガラモ場と砂浜の魚類相調査を実施した。ガラモ場と砂浜に10m四方（面積100m2）の調査区画を各4ヶ所設定し，季節に1回の頻度で（2006年8月，11月，2007年2月，5月）小型巻網（目合い4mm）を用いて区画内の魚類をすべて採集した。一年間の調査により，ガラモ場で20種以上1,397個体，砂浜で17種以上902個体の魚類が採集された。個体数にもとづく優占種（上位3種）は，ガラモ場ではシロメバル，ヒメハゼ，ハオコゼ，砂浜ではヒメハゼ，ボラ，スジハゼ，湿重量にもとづく優占種は，ガラモ場ではシロメバル，ハオコゼ，キュウセン，砂浜ではヒメハゼ，シロギス，ボラであった。100m2あたりの出現種数，個体密度，バイオマスはいずれもガラモ場において大きな季節変動を示した。8月にはガラモ場における種数が砂浜よりも有意に多かった。ガラモ場においては，ホンダワラ類の繁茂期である2－5月にシロメバル仔稚魚の来遊にともなう個体密度とバイオマスの急増が認められた。Biological and physical surveys were conducted at amacloalgae bed (MB) and a sandy beach (SB) off an inhabited island in the central Seto Inland Sea, Japan, from August 2006 tomay 2007 in order to detect the effect of vegetation on fish assemblage. Fish were collected using a seine net (2m in height, 3mm in mesh aperture) at four separate locations within MB and SB during a tidal level between 70-130 cm in daytime on 4 Aug. and 16 Nov. 2006 and 19 Feb. and 2 May 2007. A total of 1,397 and 902 fish were collected at MB and SB, respectively. The numerically dominant species were Sebastes cheni, Favonigobius gymnauchen and Hypodytes rubripinnis in MB and Favonigobius gymnauchen, mugil cephalus cephalus and Acentrogobius pflaumii in SB. Weight-based dominant species were Sebastes cheni, Hypodytes rubripinnis and Halichoeres poecilopterus in MB and Favonigobius gymnauchen, Sillago japonica and Mugil cephalus cephalus. Seasonal fluctuation in number of fish species, fish abundance and biomass in MB were larger than those in SB. The number of fish species in August in MB was significantly higher than that in SB. Fish abundance and biomass in MB abruptly increased fromFebruary to May due to immigration of S. cheni larvae and juveniles

Estimation of catch efficiency of a small seine for larval and juvenile Japanese sea bass, Lateolabrax japonicus, in the Ohta estuary

河口域における魚類群集の主要構成者であるスズキ仔稚魚に対する小型曳き網（幅2.3m，高さ1m）の採集効率を，地曳き網（幅16m，高さ1m）による採集結果と比較することにより推定した。2008年3月21日と4月7日に太田川放水路感潮域において合計15回の曳網を行い，合計1,502個体（標準体長14.5－24.0mm）のスズキ仔稚魚を採集した。地曳き網の網目からの逸出が生じる体長16mm未満と，個体密度が著しく低下する23mm以上については解析対象とせず，地曳き網による採集効率を100％と仮定した。体長1mmごとに区分した分布密度を採集具間で比較した結果，小型曳き網による体長16mm以上18mm未満のスズキ仔稚魚採集効率は約100％と推定された。体長18mm以上23mm未満では採集効率（C, ％）が体長（L, mm）に比例して直線的に減少した（C=－17.2*L+388.8，n=11，r2=0.77，p=0.0004）。In order to estimate catch efficiency of a small seine (1.0 by 2.3 m, 2 mm mesh aperture) for larval and juvenile Japanese sea bass Lateolabrax japonicus, results from experimental hauls of the small seine were compared with those from a large seines (1.0 by 16 m, 2.5 mm mesh aperture) in the Ohta Diversion Channel on March 21 and April 7, 2008. A total of 1,502 Japanese sea bass, ranging between 14.5 and 24.0 mm in standard length were collected. Data of fish <15.9 mm was excluded from the analysis since extrusion of these fish through the mesh of the large seine was possible. Comparison of the Japanese sea bass abundance at lengths between the small and large seines revealed that the catch efficiency of the small seine for Japanese sea bass <18.0 mm was approximately 100%. The catch efficiency decreased with the increase in fish body length between 18.0 and 22.9 mm. A linear model was fitted to the relationship between the catch efficiency (C, %) and body length (L, mm): C=－17.2*L+388.8 (n=11, r2=0.77, p=0.0004). Catch efficiency was not estimated for Japanese sea bass ＞ 23 mm since their abundance was quite low in the surveyed area probably due to migration to downriver or sea areas, which are considered as habitats for the following life stages

Identification and Validation of QTLs for Yield and Yield Components under Long-Term Salt Stress Using IR64 CSSLs in the Genetic Background of Koshihikari and Their Backcross Progenies

Unraveling the complex genetic bases and mechanisms underlying salt tolerance is of great importance for developing salt-tolerant varieties. In this study, we evaluated 42 chromosome segment substitution lines (CSSLs) carrying chromosome segments from IR64 on the genetic background of Koshihikari under salt stress. Two CSSLs, SL2007 and SL2038, produced higher plant dry weight and grain yield than did Koshihikari under the stress condition. These CSSLs also showed lower Na+ and Cl- accumulation in the leaf and whole plant at the full heading stage, which might be related to the higher grain yield and yield components. To understand the genetic control of its grain yield and yield components, a SL2007/Koshihikari F-2 population was generated for quantitative trait locus (QTL) analysis. Six QTLs for grain yield and yield-related traits were detected on chromosome 2. Using near-isogenic lines (NILs) from a SL2007/Koshihikari F-5 population, qSTGY2.2 was delimited to a 2.5 Mb region and novel qSTPN2 was delimited to a 0.6 Mb region. We also detected a novel QTL, qSTGF2, for grain filling, which was considered an important contributor to grain yield under salt stress in this CSSL. Our results provide insights into mechanisms conferring grain yield under salinity stress and new genetic resources for cloning and breeding

Genomic view of heavy-ion-induced deletions associated with distribution of essential genes in Arabidopsis thaliana

Heavy-ion beam, a type of ionizing radiation, has been applied to plant breeding as a powerful mutagen and is a promising tool to induce large deletions and chromosomal rearrangements. The effectiveness of heavy-ion irradiation can be explained by linear energy transfer (LET; keV µm-1). Heavy-ion beams with different LET values induce different types and sizes of mutations. It has been suggested that deletion size increases with increasing LET value, and complex chromosomal rearrangements are induced in higher LET radiations. In this study, we mapped heavy-ion beam-induced deletions detected in Arabidopsis mutants to its genome. We revealed that deletion sizes were similar between different LETs (100 to 290 keV μm-1), that their upper limit was affected by the distribution of essential genes, and that the detected chromosomal rearrangements avoid disrupting the essential genes. We also focused on tandemly arrayed genes (TAGs), where two or more homologous genes are adjacent to one another in the genome. Our results suggested that 100 keV µm-1 of LET is enough to disrupt TAGs and that the distribution of essential genes strongly affects the heritability of mutations overlapping them. Our results provide a genomic view of large deletion inductions in the Arabidopsis genome