17505 research outputs found
Sort by
中心性漿液性脈絡網膜症における Loculation of Fluid の存在に関わる臨床要因
Get PDF• PURPOSE: To elucidate clinical factors related to the presence of loculation of fluid (LOF) in the posterior choroid in central serous chorioretinopathy (CSC).
• DESIGN: Retrospective, cross-sectional study.
• METHODS: This single-center study included 158 eyes from 158 patients with CSC who were classified into LOF and non-LOF groups. The groups were compared for age, sex, spherical equivalent, axial length, subfoveal choroidal thickness (SCT), and scleral thickness. Using swept-source optical coherence tomography (OCT), we determined the presence of LOF based on B-scan and enface images. Scleral thickness was measured 6 mm posterior to the scleral spur in 4 directions using anteriorsegment OCT.
• RESULTS: The 158 eyes were classified into 98 eyes in the LOF group and 60 eyes in the non-LOF group. In univariable analyses, the LOF group was younger (P = .01) and had a higher male ratio (P = .03) and greater SCT (P < .001) than the non-LOF group. All scleral thicknesses at the superior, temporal, inferior, and nasal points were greater in the LOF group than in the non-LOF group (426.2 vs 395.1 μm, 445.7 vs 414.9 μm, 459.2 vs 428.8 μm, 445.4 vs 414.3 μm, all P < .05). Multivariable analyses found that SCT (odds ratio [OR] 1.02, 95% CI 1.01-1.02, P < .001) and mean scleral thickness (OR 1.02, 95% CI 1.02-1.03, P = .002) were significantly associated with the presence of LOF.
• CONCLUSION: A thick choroid and thick sclera appeared to be related to the presence of LOF in CSC.博士(医学)琉球大
Developments of a physical formula of the wave overtopping rate and new type block-mound seawall
Get PDF我が国における海岸構造物等からの越波量は、1954年以降盛んに研究が行われ、佐藤、石原ら、吉川らにより越波流量推定式が提案されてきた。特に、吉川らは、現在の越波流量推定式の基本となる直立壁を堰と考えた場合の越流式から越波流量推定式を提案している．その後、合田は、これまでの研究が主として規則波を対象としたものであったのに対して，不規則波を対象にした実験結果から相対水深と期待越波流量の関係を図に示し，海岸構造物の設計における実用的な越波量推定法を提案した。一方で、合田は、 「EurOtop overtopping manual」による越波流量算定式を吟味し，新しい統一的越波流量推定式を提案したものの，その精度に問題を残している．
本論は、日本国内で半世紀にまたがって利用されてきた従来の越波流量算定式を水理実験及び数値計算によって徹底して検討を重ね、直立護岸、消波工付直立護岸、テラス式護岸に対する護岸越波流量算定式の提案を行うことを主目的としている。消波工については、独自に開発した消波ブロックが用いられている。テラス式護岸についても、開発した消波ブロックが用いられている。本論は、以下の章からなっている。
第 1章では、本論が対象とした研究の背最や目的について述べている。
第 2章では，我が国における海岸保全の歴史と越波による災害事例及び対策事例を整理するとともに，越波による災害に関する研究事例について述べている．
第 3章では，本研究に関連する越波流量算定式に関する研究事例をレビューすると共に，越波流量に関する歴史と各時点における問題点を整理し，本研究で議論すべき課題を抽出している．
第 4章では，第 3章で抽出した課題のうち 2008年に合田が提案した越波流量算定式について，実用化のための検証と検証結果を踏まえた合田の越波流量算定式の修正を行っているさらに，合田の越波流量推定図表との隔たりの要因を， CADMAS-SURFによる数値計算値との比較で明らかにしている．
第 5章では，不規則波の持つ不規則性が越波現象に及ぼす本質を解明するため，規則波を用いて大型水理実駿を実施し， CADMAS-SURFを用いた数値計算の検証を行った上で，主として数値計算によって，水平床上の直立護岸に対する規則波の越波流量特性を明らかにしている．具体的には，無次元越波流量が相対天端高によって系統的に整理できることを示した上で，反射率と越波流量とを同時生起現象として説明している．
第 6章では，直立護岸前面に独自に開発した消波ブロックを設置する消波工付直立護岸及び遊歩道としてのテラス部を設置するテラス式護岸の提案を行い，それらの護岸に対する越波特性を水理実験及び CADMAS-SURFを用いた数値計算で明らかにしている．
第 7章では，本研究の総括が行われている．博士（工学）琉球大
石灰岩地域における環境水中トリチウムおよびラドンの挙動に関する研究
Get PDF亜熱帯島嶼地域における環境水中のトリチウム (H^3) とラドン (Rn^) の挙動を明らかにするとともに、トリチウムとラドンをトレーサーとして比較的空隙の多い離水サンゴ礁起源の石灰岩地域における地下水の浸透量や滞留時間を推定するため、日本の南西部に位置する沖縄島における環境水中のトリチウムおよびラドン濃度の季節変動とその分布に関する研究を実施した。 2014年 6月から、沖縄島南部の鍾乳洞（玉泉洞）内滴下水と中南部 2ヶ所の湧水（森の川、垣花樋川）について毎月試料を採取した。また、南部の米須では 2018年 4月から、受水では 2018年 5月から湧水試料の採取を開始した。さらに、 2014年 6月から沖縄島中部に所在する琉球大学において降水の毎月採取を実施している。降雨については全国的な比較を行うため、北海道札幌市および岐阜県土岐市においても採取を実施した。玉泉洞、森の川、垣花樋川、受水、米須における湧水のトリチウム濃度の算術平均 ± 標準偏差は、それぞれ 0.14 ± 0.04 Bq L^、0.13 ± 0.03 Bq L^、0.13 ± 0.03 Bq L^、0.14 ± 0.03 Bq L^、および 0.15 ± 0.04 Bq L^であったことから、沖縄島中南部の陸水中トリチウム濃度には大きな時間変動はなく、空間的にも概ね一様な濃度分布であることが認められた。降水中トリチウム濃度の算術平均 ± 標準偏差（濃度範囲）は、 0.14 ± 0.06 Bq L^ (0.05-0.39 Bq L^) であり、春季に高く秋季に低いという季節変動がみられた。また、同時期に採取した北海道と岐阜県の降水中トリチウム濃度の算術平均 ± 標準偏差（濃度範囲）は、それぞれ 0.69 ± 0.30 Bq L^ (0.16-1.59 Bq L^)、岐阜県で 0.32 ± 0.12 Bq L^ (0.10-0.86 Bq L^) であった。これらから、高緯度地域である北海道で濃度が高く、低緯度地域である沖縄県で最も低い値となる緯度効果が確認された。玉泉洞、受水、米須の 3ヶ所で得た 2016年 10月以降の試料について、水中ラドン濃度測定を実施したところ、算術平均値 ± 標準偏差はそれぞれ 10 ± 1.3 Bq L^、3.2 ± 1.0 Bq L^、および 3.1 ± 1.1 Bq L^であった。水中ラドン濃度は夏季から秋季にかけて徐々に増加する傾向を示し、冬季には減少した。単純なラドン挙動モデルから、玉泉洞を胚胎する石灰岩体については降水が 7～10日で洞内に浸透すること、この石灰岩体を覆う土嬢中の降水滞留時間は約 50～80日であると推定された。また、受水と米須における石灰岩中の地下水の滞留時間は、それぞれ 12～21日と 12～19日であった。さらに、採取した降水中の水素・酸素安定同位体比とイオン成分を分析し、これに大気の後方流跡線解析の結果を組み合わせることによって降水中トリチウム濃度の変動要因について検証した結果、沖縄島の大気が年間を通して周辺海洋の影響を強く受けていること、特に黒潮流域から大気へ供給される水蒸気が大きく影響していることが示唆された。 トリチウム及びラドンの環境動態（特に降水のインプット情報、湧水などのアウトプット情報）を理解することで、石灰岩地域における地下水の時間情報を推定することが可能である。博士(学術)琉球大
機械学習を用いた太陽光エネルギーの出力を予測する説明的研究アプローチに関する研究
Get PDFArtificial intelligence (AI) techniques play a crucially important role in predicting the expected energy outcome and its performance, analysis, modeling and control of renewable energy.
Solar energy usage has grown exponentially over the years. In the face of global energy consumption and increased depletion of most fossil fuel, the world is faced with the challenges of meeting the ever-increasing energy demands, also utility companies who provide solar energy have a challenge of unstable input of solar energy to the grid due to its intermittent nature, unlike other sources, hence the difference between expected generation and actual generation, demand and supply can lead to an unbalanced grid.
Therefore, incorporating accurately machine learning technology to predict the expected outcome of solar energy from the intermittent solar radiation will be crucial to keep a balance grid operation between supply and demand, production planning and energy management especially during installations of a photo-voltaic power plant.
However, one of the major problems of forecasting is the algorithms used to control, model, and predict performances of the energy systems which are complicated and involves large computer power, differential equations, and time series. Also having unreliable data (poor quality) for solar radiation over a geographical location as well as insufficient long series can be a bottleneck to actualization. To overcome these problems, we employ the anaconda Navigator (Jupyter Notebook) for machine learning which can combine large amounts of data with fast, iterative processing and intelligent algorithms allowing the software to learn automatically from patterns or features to predict the performance and outcome of Solar Energy which in turns enables the balance between supply and demand on loads, efficient operation of the utility company as well as enhances power production planning and management.
Firstly, the thesis describes the need for alternative source of energy generation in developing countries, next, it focuses on forecasting the output power of solar systems is required for the good operation of the power grid or for the optimal management of the energy fluxes occurring into the.solar system. Finally, the proposed methods is being summarized. Scopes of future research have also been described.博士（工学）琉球大
沖縄の人工物上で生育する異質細胞性シアノバクテリアの多様性と系統分類に関する研究
Get PDFMan-made structures such as buildings and guardrails in Okinawa are often stained black or brown, and the main cause is known to be the growth of aerobic cyanobacteria. Previous studies have isolated and cultured aerobic cyanobacteria from the walls of the school buildings on the campus of the University of the Ryukyus, and have found that they are composed of extremely diverse taxa via morphological observations and molecular phylogenetic analyses based on the 16S rRNA gene sequences. The current study focuses on these diverse aerobic cyanobacteria, and especially Nostocales cyanobacteria, which are known to have nitrogen-fixing ability via heterocytes, and their diversity and phylogenetic classification have already been established. In addition to already isolated strains, new isolates were added during this study. This thesis is divided into five chapters. Chapter 1 summarizes the current classification of cyanobacteria and outlines the latest polyphasic taxonomy research methods. The current classification of cyanobacteria is based on 16S rRNA gene based on Komárek et al. (2014) and accurate morphological classification. Chapter 2 shows the classification of filamentous cyanobacteria involved in black band disease, which is one of the coral diseases in Okinawa, as an example of research on polyphasic taxonomy research. As a result, we succeeded in analyzing the 16S rRNA gene sequences of cyanobacteria collected from the Okinawajima and Miyakojima islands by the single filament PCR method, and there were almost no differences among samples, which were identified as Roseofilum reptotaenium. Culture strains were also successfully established. In Chapter 3, in addition to the culture strains established in the previous research from the campus of the University of the Ryukyus, we newly established isolated strains from artificial objects such as guard rails and building walls in Okinawa, containing diversified heterocystous aerobic cyanobacteria. The strains were analyzed by molecular phylogenetic analyses based on the 16S rRNA gene sequences and light microscopic observations. This study found 12 groups that were difficult to morphologically distinguish, and revealed that is highly possible that undescribed taxa were included. Chapter 4 examined the genus Brasilonema among the various heterocystous cyanobacteria clarified in the previous chapter, and showed phylogenetic classification by morphological observations and 16S rRNA and l 6S-23S ITS analyses. Chapter 5 gives a summary of this study and future prospects.博士（学術）琉球大
Latitudinal Variation in Sexual Selection Pressure in Ricefishes of the family Adrianichthyidae
Get PDFTropical animals are characterized by showy ornaments and conspicuous body colors as compared with temperate relatives. Some studies hypothesized that sexual selection pressures are stronger in the tropics than in the temperate zone. However, this is not a collective view. In this study, I demonstrate the latitudinal variation in sexual selection pressures, using ricefishes (Adrianichthyidae), which is having a wide geographic range throughout Southeast and East Asia, as a model system.
First, comparisons of the degree of sexual dimorphisms in body size, fin lengths, and body coloration among 32 adrianichthyid species revealed that lower-latitude species are sexually more dimorphic in all characters than higher-latitude species. PGLS analyses using a mitochondrial DNA phylogeny demonstrated that the negative correlations between latitude and the degree of sexual dimorphisms/dichromatism become non-significant when phylogeny is considered, but that the variance in the degree of sexual dimorphisms is explained not only by phylogeny but also almost equally by latitude. Ancestral state reconstruction indicated that sexual dimorphisms/dichromatism have evolved independently even within major clades. These findings indicating that tropical species are exposed to stronger sexual-selection pressures than temperate ones.
Second, I compared mating behaviors between a tropical (Oryzias woworae) and a temperate (Oryzias sakaizumii). Mating experiments revealed that males of O. woworae are more aggressive in male-male interaction and more active in courting females than O. sakaizumii males. In addition, O. woworae females tended to reject male courtships more frequently than O. sakaizumii females, indicating that O. woworae females are choosier in mating than O. sakaizumii females. These findings are concordant with the view that O. woworae is exposed to stronger sexual-selection pressures than O. sakaizumii.
Third, I compared seasonal patterns in the occurrence of mature individuals in the wild among three latitudinal species (O. sakaizumii, O. latipes, and O. woworae) to test if operational sex ratios (OSRs), which is a determinant of the strength of sexual selection pressures, are more male-biased at low latitudes. Field collections revealed that mature females and males appear throughout the year in the tropical species (O. woworae). However, OSRs were strongly male-biased throughout the year (male : female = ca. 1 : 3). This bias in OSRs in O. woworae was much stronger than the bias in the temperate (O. sakaizumii) and sub-tropical (O. latipes) congeners, in which both mature females and males occur in greater synchrony during a shorter period of the year, and therefore OSRs are less biased. Thus, OSRs were estimated to be more male-biased at lower latitudes, as expected, supporting that sexual selection pressures are stronger in tropical species than temperate species.
Thus, I demonstrated that latitudinal variation in OSRs, as a determinant of sexual selection pressures, leads to the evolution of latitudinal variation in sexual dimorphisms and mating behaviors. I conclude that this explains why tropical animals are characterized by showy ornaments and conspicuous body colors.博士（理学）琉球大学University of the Ryukyu
Studies on comparative genetic population structure of four marine or ganisms across the biogeographical barrier, the Wallace Line
Get PDFThe targeted species in this study are the fiddler crab Austruca perplexa, the shallow water shrimp Acetes sibogae sibogae, the Javanese ricefish Oryziasjavanicus, and the Asian monsoon scallops Amusium pleuronectes has long been of interest to evolutionary biologist because of the high level of species diversity, its wide geographic distribution, and its economic and ecologically importance. Many of these pressures, including increasing sea-surface temperatures, ocean acidification, pollution, legal and illegal overfishing, destructive fishing methods, water diversions, and other environmental shifts have the potential to result in significant loss of specific biodiversity stock, necessitating careful management wherever possible.
Genetic approaches are one tool that can help inform the conservation and management objectives unique to marine systems. Population genetic tools offer an opportunity to elucidate the genetic level (speciation and diversification), patterns of dispersal (connectivity and migration), and demographics (past and present), to better understand species' responses to ecological changes, anthropogenic stressors, and biogeographical
We compare the patterns of genetic diversity and natural population structure in the target species were investigated to gain a better understanding.of its evolutionary history. Samples were collected from Western Pacific Region, especially across the biogeographical barrier, the Wallace line. We characterized sequence variation in an mtDNA control region fragment for all targeted species and microsatellite loci for O. javanicus. The genetic diversity result showed the height haplotype diversity and low nucleotide diversity (for Au. perplexa and Am. pleuronectes), intermediate haplotype diversity and low nucleotide diversity (for Ac. s. sibogae), and both low haplotype and nucleotide diversity (for O. javanicus). Analysis of molecular variance revealed significant genetic differentiation (P < 0.0001) among all sampled sites for both genetic markers accept Am. pleuronectes. Furthermore, the mean fixation indices for both genetic markers were relatively high, indicating that dispersal potential among sites was low and that gene flow had been restricted in the past. This pattern of population structure likely reflects a short pelagic larval life and is associated with very limited dispersal potential, leading to isolation by distance, potentially allowing local adaptation to sites that augment any oceanographic, geographic, or biological barriers to gene flow. The patterns of genetic differentiation resulting from this combination of factors represent a source of evolutionary novelty.博士（学術）琉球大学University of the Ryukyu
超音波生体顕微鏡を用いた原発閉塞隅角病の毛様小帯脆弱の評価
Get PDFPurpose: To evaluate zonular weakness before cataract surgery in eyes with primary angle closure disease (PACD). Study design: Retrospective Methods: This study was conducted at the University of the Ryukyus, Okinawa, Japan. We analyzed data from 133 eyes in 106 consecutive patients with PACD who underwent cataract surgery. PACD included PACS (primary angle closure suspect), PAC (primary angle closure), and PACG (primary angle closure glaucoma). We compared 68 eyes with zonular weakness and 65 eyes without zonular weakness, as identified during surgery. We developed three new ultrasound biomicroscopy (UBM) parameters. The SS-CP and SS-LS parameters were defined as the vertical distance between the scleral spur (SS) and the ciliary process (CP) or the lens surface (LS), respectively. The CP-LS parameter was defined as the distance between the CP and the LS. Results: Of the 133 eyes, 18 (13.5%), 50 (37.6%), and 65 (48.9%) were diagnosed with PACS, PAC, and PACG, respectively. Of the 68 eyes with zonular weakness, 8 eyes needed sulcus fixation of the intra ocular lens (IOL) because of lens subluxation. CP-LS was longer in eyes that required sulcus fixation of the IOL than in those that did not require sulcus fixation of the IOL (P < 0.01).
Conclusions: A longer distance between the CP and the edge of the lens surface (CP-LS) necessitated a more difficult cataract surgery and greater frequency of sulcus fixation of the IOL. UBM examination is useful for detecting zonular weakness before surgery in PACD eyes.博士(医学)琉球大