379 research outputs found
Measurement of Sparks and Dusts Released from an ICRF Antenna Just before Termination of an ICRF Heated Long Pulse Discharge
Florística e fitossociologia de uma floresta ecotonal em topossequência às margens de reservatório hidrelétrico no médio Iguaçu
Orientador: Prof. Dr. Christopher Thomas BlumCoorientadores: Prof. Dr. Román Carlos Ríos e Dr. Murilo Lacerda BarddalDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Programa de Pós-Graduação em Engenharia Florestal. Defesa : Curitiba, 18/09/2020Inclui referências: p.76-86Área de concentração: Conservação da NaturezaResumo: O presente estudo faz parte do projeto PD-06491-0405/2015 executado pela unidade de pesquisa e desenvolvimento da COPEL GeT em parceria com a UFPR e o Simepar, com o apoio da ANEEL, através de seu programa de desenvolvimento científico de aplicações de energia elétrica. O Brasil se destaca mundialmente pelo potencial de geração de energia hidrelétrica. Embora propiciem benefícios e sejam fundamentais, os projetos hidrelétricos causam transformações na paisagem e distúrbios aos ecossistemas. Também em nível mundial, o Brasil tem destaque pelas suas florestas, reconhecidas pela elevada biodiversidade. A floresta atlântica é frequentemente destacada pelo endemismo, mas também pela sua devastação. Perante tais fatos, fica evidente a importância de estudos sobre a relação dos empreendimentos hidrelétricos com os remanescentes florestais do bioma, não se restringindo aos impactos ambientais, mas sim buscando subsídios para uma coexistência sustentável. O objetivo desta pesquisa foi caracterizar a florística e fitossociologia de um remanescente de Mata Atlântica com 38 anos de sucessão secundária em topossequência marginal a reservatório hidrelétrico, assim como investigar as variáveis ambientais e sua influência na vegetação. A área de estudo localiza-se no município de Bituruna/PR, nas proximidades da Usina Hidrelétrica Governador Bento Munhoz da Rocha Netto. A barragem foi construída no médio rio Iguaçu, Terceiro Planalto Paranaense, em região caracterizada pela situação ecotonal entre as Florestas Ombrófila Mista e Estacional Semidecidual. Foram instaladas 60 parcelas de 200 m² para o estrato arbóreo, DAP ? 10 cm, e 60 subparcelas de 10 m² para o sub-bosque, 10 cm > DAP ? 1 cm, distribuídas em três setores da encosta (terços inferior, médio e superior). Nas unidades amostrais foram coletados dados de caracterização pedológica, topográfica e amostras compostas de solo para análises física e química. Por meio de abordagens estatísticas foram analisadas as variáveis ambientais e a composição florístico-fitossociológica de cada setor da encosta, assim como suas correlações. Com relação às sinúsias estudadas, o estrato arbóreo apresentou densidade de 1.035 indivíduos/ha, área basal de 38,98 m²/ha, 108 espécies nativas e diversidade H' exponencial de 55,1. No sub-bosque foi registrada densidade de 11.000 indivíduos/ha, área basal de 8,65 m²/ha, 96 espécies nativas e diversidade H' exponencial de 39,3. O grupo ecológico das não pioneiras se destacou e as espécies típicas de Floresta Estacional Semidecidual foram discretamente mais representativas do que as de Floresta Ombrófila Mista. Atestou-se a dissimilaridade na composição florística entre o estrato arbóreo e o sub-bosque. A floresta mostrou bom estado de conservação e características de estágio sucessional intermediário a avançado. A proporção de espécies típicas de cada tipo florestal correspondeu ao esperado para as condições altitudinais e topográficas do ecótono. Com relação à setorização da encosta, o terço inferior se mostrou diferenciado ambiental e floristicamente dos demais e os principais fatores foram a declividade, cota altimétrica e concentração de matéria orgânica. A composição florístico-estrutural do referido setor também se mostrou diferenciada, sendo que no estrato arbóreo foi detectada influência da declividade, enquanto o sub-bosque teve influência da cota. Ambas sinúsias foram influenciadas por propriedades edáficas relacionadas à concentração de matéria orgânica. Palavras-chave: Estrato arbóreo. Sub-bosque. Solo. Relevo. Mata Atlântica.Abstract: This study is part of the project PD-06491-0405/2015 carried out by the research and development unit of the COPEL GeT in partnership with the UFPR and Simepar, sponsored by the ANEEL, through its program of scientific development of electrical energy applications. Brazil stands out worldwide by the potential of hydroelectric power generation. Although hydroelectric projects provide benefits and are fundamental, they cause changes in the landscape and disturbances to ecosystems. Also at a global level, Brazil stands out by its forests, recognized for their high biodiversity. The Atlantic Forest is often highlighted by the endemism, but also by the devastation. Considering these facts, the importance of studies regarding the relationship of hydroelectric projects with the forest remnants is evident, not being restricted to the environmental impacts, but rather seeking subsidies for sustainable coexistence. The aim of this research was to characterize the floristics and phytosociology of a Mata Atlântica remnant with 38 years of secondary succession in topographic sequence contiguous to a hydroelectric reservoir, as well as to investigate the environmental variables and their influence on vegetation. The study area is located in Bituruna/PR, near the Governador Bento Munhoz da Rocha Netto Hydroelectric Plant. The dam was built in the region of the middle Iguaçu River, Terceiro Planalto Paranaense, in a region characterized by the ecotonal situation between the Araucária rainforest and Semideciduous Seasonal Forest. There were installed 60 plots with 200 m² for the arboreal stratum, DAP ? 10 cm, and 60 subplots with 10 m² for the understory stratum, 10 cm > DAP ? 1 cm, distributed in three hillside sectors (lower, middle and upper). In each plot, pedologic and topographic characterization was made and soil composite samples were collected for physical and chemical analysis. Through statistical approaches, the environmental variables and the phytosociological composition of each sector were analyzed, as well as their correlations. Regarding the studied communities, the arboreal stratum presented density of 1,035 individuals/ha, basal area of 38.98 m²/ha, 108 native species and H' exponential diversity of 55.1. In the understory stratum were registered density of 11,000 individuals/ha, basal area of 8.65 m²/ha, 96 native species and H' exponential diversity of 39.3. The non-pioneers ecological group stood out and the typical species of the Semideciduous Seasonal Forest were slightly more representative than typical species of the Araucária Rainforest. Floristic composition dissimilarity was detected between the arboreal and understory stratum. The forest showed good conservation status and intermediate to advanced successional stage characteristics. The typical species proportion of each forest type corresponded with the expected for altitudinal and topographic conditions of the ecotonous. Regarding the hillside sectorization, the lower sector showed up environmentally and floristically differences from the others and the main cause factors were the declivity, topographic level and organic matter concentration. The floristic and structural composition of lower sector also showed a difference, with the influence of the arboreal stratum, while the understory stratum was influenced by the topographic level. Both communities were influenced by soil properties related to the organic matter concentration. Keywords: Arboreal stratum. Understory stratum. Soil. Relief. Atlantic Forest
Circumferential Spinal Cord Decompression through a Single Posterior Approach with Microendoscopy for Thoracic and Thoracolumbar Ossification of the Posterior Longitudinal Ligament
Thoracic and thoracolumbar ossification of the posterior longitudinal ligament (OPLL) can be difficult to treat due to the anatomical position. The purpose of this study was to report the significance of a novel surgical technique that represented two cases of thoracic or thoracolumbar OPLL. The first patient was a 72-year-old woman who had a beak-type OPLL at the T11/12. The second was a 45-year-old woman who had a beak-type OPLL at the T12/L1. We performed circumferential spinal cord decompression through a single posterior approach with microendoscopy in both cases. The postoperative computed tomography revealed the complete removal of the OPLL, and the magnetic resonance imaging confirmed adequate decompression of the spinal cord. Preoperative symptoms were substantially improved in both patients. To date, we have used this novel technique to treat five patients with thoracic or thoracolumbar OPLL. This new surgical technique is likely to be useful in patients with a beak-type OPLL of the thoracic or thoracolumbar spine
Unveiling charge dynamics of visible light absorbing oxysulfide for efficient overall water splitting
Oxysulfide semiconductor, Y2Ti2O5S2, has recently discovered its exciting potential for visible-light-induced overall water splitting, and therefore, imperatively requires the probing of unknown fundamental charge loss pathways to engineer the photoactivity enhancement. Herein, transient diffuse reflectance spectroscopy measurements are coupled with theoretical calculations to unveil the nanosecond to microsecond time range dynamics of the photogenerated charge carriers. In early nanosecond range, the pump-fluence-dependent decay dynamics of the absorption signal is originated from the bimolecular recombination of mobile charge carriers, in contrast, the power-law decay kinetics in late microsecond range is dominated by hole detrapping from exponential tail trap states of valence band. A well-calibrated theoretical model estimates various efficiency limiting material parameters like recombination rate constant, n-type doping density and tail-states parameters. Compared to metal oxides, longer effective carrier lifetime ~6 ns is demonstrated. Different design routes are proposed to realize efficiency beyond 10% for commercial solar-to-hydrogen production from oxysulfide photocatalysts
Jiadifenolide induces the expression of cellular communication network factor (CCN) genes, and CCN2 exhibits neurotrophic activity in neuronal precursor cells derived from human induced pluripotent stem cells
Jiadifenolide has been reported to have neurotrophin-like activity in primary rat cortical neurons, and also possesses neurotrophic effects in neuronal precursor cells derived from human induced pluripotent stem cells (hiPSCs), as we have previously reported. However, the molecular mechanisms by which jiadifenolide exerts its neurotrophic effects in rat and human neurons are unknown. Thus, we aimed to investigate the molecular mechanisms and pathways by which jiadifenolide promotes neurotrophic effects. Here, we found that jiadifenolide activated cellular communication network factor (CCN) signaling pathways by up-regulating mRNA level expression of CCN genes in human neuronal cells. We also found that CCN2 (also known as connective tissue growth factor, CTGF) protein promotes neurotrophic effects through activation of the p44/42 mitogen-activated protein kinase signaling pathway. This is the first discovery which links neurotrophic activity with CCN signaling
Use of Material Safety Data Sheets at Workplaces Handling Harmful Substances in Okayama, Japan
Abstract: Use of Material Safety Data Sheets at Workplaces Handling Harmful Substances in Okayama, Japan: Akihiko SEKI, et al. Department of Public Health, Okayama University Medical School-In April 2000, the revised Industrial Safety and Health Law, which prescribes the creation and issue of material safety data sheets (MSDSs), was enforced in Japan. Before the enforcement, we conducted a survey relating to the use of MSDSs in hazardous workplaces in Okayama Prefecture, Japan. We sent questionnaires to all workplaces possibly using hazardous chemicals, and answers from 422 workplaces, where hazardous chemicals were used but not produced, were analyzed. One-third of the workplaces did not request MSDSs at the time of chemical transfer. In more than half of the workplaces, MSDSs were not posted or kept. The main reason for such lack of use or misuse of the MSDS system was a lack of knowledge and understanding of the system. In addition, half of the respondents considered that MSDS documents were unsatisfactory because of the difficult words used in them. These two problems, i.e., a lack of knowledge and understanding of the MSDS system, and the use of difficult words in the documents, should be remedied in order for the MSDS system to be implemented effectively and thereby protect workers from the harmful effects of chemicals. (J Occup Health 2001; 43: 95-100
Development of steady-state operation using ion cyclotron heating in the Large Helical Device
Using a handshake shape (HAS) antenna phasing dipole for ion cyclotron heating (ICH), the heating efficiency was higher than that using a previous poloidal array antenna in the Large Helical Device. In order to sustain the dipole operation, real-time feedback for impedance matching and maintaining the same phase and power was adopted during long-pulse discharge. The HAS antenna was designed to reduce parasitic losses associated with energetic particle and radio-frequency (RF) sheath effects by field-aligned current concentration on the midplane. Local hot spots and the inhomogeneity of the diverter heat profile in the toroidal direction were reduced. The long-pulse discharge with an electron density (n e0) of 1?×?1019 m?3, center electron temperature (T e0) of 2.5?keV, a plasma duration time (t d) of 19?min, and RF heating power (P RF ) of 1?MW was achieved by ICH and electron cyclotron heating
Studies of dust transport in long pulse plasma discharges in the large helical device
Three-dimensional trajectories of incandescent dust particles in plasmas were observed with stereoscopic fast framing cameras in a large helical device. It proved that the dust is located in the peripheral plasma and most of the dust moves along the magnetic field lines with acceleration in the direction that corresponds to the plasma flow. ICRF heated long pulse plasma discharges were terminated with the release of large amounts of dust from a closed divertor region. After the experimental campaign, the traces of exfoliation of carbon rich mixed-material deposition layers were found in the divertor region. Transport of carbon dust is investigated using a modified dust transport simulation code, which can explain the observed dust trajectories. It also shows that controlling the radius of the dust particles to less than 1 mm is necessary to prevent the plasma termination by penetration of dust for the long pulse discharges. Dust transport simulation including heavy metal dust particles demonstrates that high heating power operation is effective for shielding the main plasma from dust penetration by an enhanced plasma flow effect and a high heat load onto the dust particles in the peripheral plasma. It shows a more powerful penetration characteristic of tungsten dust particles compared to that of carbon and iron dust particles
<Abstract of Published Report>High Susceptibility of p53(+/-)Knockout Mice in N-Butyl-N-(4-hydroxybutyl)nitrosamine Urinary Bladder Carcinogenesis and Lack of Frequent Mutation in Residual Allele.
A Statistical Study of the Solar Wind Dependence of Multi-Harmonic Toroidal ULF Waves Observed by the Arase Satellite
Toroidal standing Alfvén wave is one of the ultra-low frequency waves that are frequently observed in the terrestrial magnetosphere. They sometimes exhibit multi-harmonic frequency spectra, indicating wide energy range input in the magnetosphere. However, their energy source has not been fully understood due to the lack of statistical studies. Here we used the data of the Arase satellite observations for ∼3.5 years and conducted a statistical analysis of the solar wind dependence of the occurrence rate, wave power, and frequency of the multi-harmonic toroidal waves. We automatically detected the multi-harmonic waves and categorized them into four groups according to the solar wind velocity and the cone angle of the interplanetary magnetic field. We found that the occurrence rate and wave power of the multi-harmonic waves increase with the solar wind velocity on the flank sides. In the noon sector, the occurrence rate of the multi-harmonic waves increases with the decrease of the cone angle. The median frequency of the multi-harmonic waves on the dayside is positively correlated with the upstream wave frequency predicted by the theory of the ion beam instability for a small cone angle. The occurrence rate also increases with the solar wind dynamic pressure fluctuations. Therefore, we suggest that the Kelvin-Helmholtz instability, the upstream waves, and the dynamic pressure fluctuations are possible sources of the multi-harmonic waves. This study sheds light on the activity of the multi-harmonic waves which can affect radiation belt electrons under various solar wind conditions
- …