47 research outputs found
Holographic Pseudo Entropy
We introduce a quantity, called pseudo entropy, as a generalization of
entanglement entropy via post-selection. In the AdS/CFT correspondence, this
quantity is dual to areas of minimal area surfaces in time-dependent Euclidean
spaces which are asymptotically AdS. We study its basic properties and
classifications in qubit systems. In specific examples, we provide a quantum
information theoretic meaning of this new quantity as an averaged number of
Bell pairs when the post-selection is performed. We also present properties of
the pseudo entropy for random states. We then calculate the pseudo entropy in
the presence of local operator excitations for both the two dimensional free
massless scalar CFT and two dimensional holographic CFTs. We find a general
property in CFTs that the pseudo entropy is highly reduced when the local
operators get closer to the boundary of the subsystem. We also compute the
holographic pseudo entropy for a Janus solution, dual to an exactly marginal
perturbation of a two dimensional CFT and find its agreement with a
perturbative calculation in the dual CFT. We show the linearity property holds
for holographic states, where the holographic pseudo entropy coincides with a
weak value of the area operator. Finally, we propose a mixed state
generalization of pseudo entropy and give its gravity dual.Comment: 92 pages, 25 figures; v3: discussion improved, comments adde
Integration of Multi-Sensor Data to Estimate Plot-Level Stem Volume Using Machine Learning Algorithms–Case Study of Evergreen Conifer Planted Forests in Japan
The development of new methods for estimating precise forest structure parameters is essential for the quantitative evaluation of forest resources. Conventional use of satellite image data, increasing use of terrestrial laser scanning (TLS), and emerging trends in the use of unmanned aerial systems (UASs) highlight the importance of modern technologies in the realm of forest observation. Each technology has different advantages, and this work seeks to incorporate multiple satellite, TLS- and UAS-based remote sensing data sets to improve the ability to estimate forest structure parameters. In this paper, two regression analysis approaches are considered for the estimation: random forest regression (RFR) and support vector regression (SVR). To collect the dependent variable, in situ measurements of individual tree parameters (tree height and diameter at breast height (DBH)) were taken in a Japanese cypress forest using the nondestructive TLS method, which scans the forest to obtain dense and accurate point clouds under the tree canopy. Based on the TLS data, the stem volume was then computed and treated as ground truth information. Topographic and UAS information was then used to calculate various remotely sensed explanatory variables, such as canopy size, canopy cover, and tree height. Canopy cover and canopy shapes were computed via the orthoimages derived from the UAS and watershed segmentation method, respectively. Tree height was computed by combining the digital surface model (DSM) from the UAS and the digital terrain model (DTM) from the TLS data. Topographic variables were computed from the DTM. The backscattering intensity in the satellite imagery was obtained based on L-band (Advanced Land Observing Satellite-2 (ALOS-2) Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2)) and C-band (Sentinel-1) synthetic aperture radar (SAR). All satellite (10–25 m resolution), TLS (3.4 mm resolution) and UAS (2.3–4.6 cm resolution) data were then combined, and RFR and SVR were trained; the resulting predictive powers were then compared. The RFR method yielded fitting R2 up to 0.665 and RMSE up to 66.87 m3/ha (rRMSE = 11.95%) depending on the input variables (best result with canopy height, canopy size, canopy cover, and Sentinel-1 data), and the SVR method showed fitting R2 up to 0.519 and RMSE up to 80.12 m3/ha (rRMSE = 12.67%). The RFR outperformed the SVR method, which could delineate the relationship between the variables for better model accuracy. This work has demonstrated that incorporating various remote sensing data to satellite data, especially adding finer resolution data, can provide good estimates of forest parameters at a plot level (10 by 10 m), potentially allowing advancements in precision forestry
An Evaluation of the Long-Term Stagnancy of Porewater in the Neogene Sedimentary Rocks in Northern Japan
Retrospective comparison of clinical and angiographic outcomes after primary stenting using sirolimus-eluting and bare-metal stents in nonrandomized consecutive 568 patients with first ST-segment elevated myocardial infarctions
SummaryBackground and purposeThe long-term safety and efficacy of primary stenting using drug-eluting stents (DES) in patients with ST-segment elevation myocardial infarction (STEMI) are not fully understood in Japan. Therefore, we retrospectively examined the midterm clinical and angiographic outcomes in STEMI patients after primary stenting using sirolimus-eluting stents (SES) in a clinical setting through a historical comparison with those of bare-metal stents (BMS).Methods and resultsThe study design was a retrospective, nonrandomized, and single-center study. The clinical outcomes for 568 consecutive patients who presented within 12h of their first STEMI and who were treated with BMS (n=198; 184 STEMIs from June 2003 to August 2004 and 14 STEMIs from September 2004 to May 2007) or SES (n=370; from August 2004 to May 2007) at our medical center in Japan were retrospectively investigated in February 2010. The incidence of post-discharge events (comprising cardiac death and nonfatal recurrent MI) after SES placement (3.9%) was not significantly different from that after BMS placement (6.7%). SES was not related to the risk of post-discharge events (mean follow-up for SES, 1327±415 days; BMS, 1818±681 days) (hazard ratio of 0.369 at 95% CI, 0.119–1.147, p=0.085). The incidence of definite stent thromboses after SES placement (0.54%) was not significantly higher than that after BMS placement (0%). The incidence of binary in-stent restenosis (% diameter stenosis of more than 50% at secondary angiography) after SES placement (8.3%) was significantly lower than that after BMS placement (25.7%; p<0.001).ConclusionsFrom the present historical comparison of SES and BMS, we conclude that primary stenting using SES in a clinical setting has favorable clinical and angiographic outcomes in Japanese STEMI patients
Transition between Isotope-Mixing and Nonmixing States in Hydrogen-Deuterium Mixture Plasmas
The transition between isotope-mixing and nonmixing states in hydrogen-deuterium mixture plasmas is observed in the isotope (hydrogen and deuterium) mixture plasma in the Large Helical Device. In the nonmixing state, the isotope density ratio profile is nonuniform when the beam fueling isotope species differs from the recycling isotope species and the profile varies significantly depending on the ratio of the recycling isotope species, although the electron density profile shape is unchanged. The fast transition from nonmixing state to isotope-mixing state (nearly uniform profile of isotope ion density ratio) is observed associated with the change of electron density profile from peaked to hollow profile by the pellet injection near the plasma periphery. The transition from nonmixing to isotope-mixing state strongly correlates with the increase of turbulence measurements and the transition of turbulence state from TEM to ion temperature gradient is predicted by gyrokinetic simulation
The isotope effect on impurities and bulk ion particle transport in the Large Helical Device
The isotope effect on impurities and bulk ion particle transport is investigated by using the deuterium, hydrogen, and isotope mixture plasma in the Large Helical Device (LHD). A clear isotope effect is observed in the impurity transport but not the bulk ion transport. The isotope effects on impurity transport and ion heat transport are observed as a primary and a secondary effect, respectively, in the plasma with an internal transport barrier (ITB). In the LHD, an ion ITB is always transient because the impurity hole triggered by the increase of ion temperature gradient causes the enhancement of ion heat transport and gradually terminates the ion ITB. The formation of an impurity hole becomes slower in the deuterium (D) plasma than the hydrogen (H) plasma. This primary isotope effect on impurity transport contributes the longer sustainment of the ion ITB state because the low ion thermal diffusivity can be sustained as long as the normalized carbon impurity gradient R/Ln,c, where , is above the critical value (~−5). Therefore, the longer sustainment of the ITB state in the deuterium plasma is considered to be a secondary isotope effect due to the mitigation of the impurity hole. The radial profile of H and D ion density is measured using bulk charge exchange spectroscopy inside the isotope mixture plasma. The decay time of H ion density after the H-pellet injection and the decay time of D ion density after D-pellet injection are almost identical, which demonstrates that there is no significant isotope effect on ion particle transport
Measurement on Diffusion Coefficients and Isotope Fractionation Factors by a Through-Diffusion Experiment
For radioactive waste disposal, it is important that local groundwater flow is slow as groundwater flow is the main transport medium for radioactive nuclides in geological formations. When the groundwater flow is very slow, diffusion is the dominant transport mechanism (diffusion-dominant domain). Key pieces of evidence indicating a diffusion-dominant domain are the separation of components and the fractionation of isotopes by diffusion. To prove this, it is necessary to investigate the different diffusion coefficients for each component and the related stable isotope fractionation factors. Thus, in this study, through-diffusion and effective-porosity experiments were conducted on selected artificial materials and natural rocks. We also undertook measurements relating to the isotope fractionation factors of Cl and Br isotopes for natural samples. For natural rock samples, the diffusion coefficients of water isotopes (HDO and H218O) were three to four times higher than those of monovalent anions (Cl−, Br- and NO3−), and the isotope fractionation factor of 37Cl (1.0017–1.0021) was slightly higher than that of free water. It was experimentally confirmed that the isotope fractionation factor of 81Br was approximately 1.0007–1.0010, which is equivalent to that of free water. The enrichment factor of 81Br was almost half that of 37Cl. The effective porosity ratios of HDO and Cl were slightly different, but the difference was not significant compared to the ratio of their diffusion coefficients. As a result, component separation was dominated by diffusion. For artificial samples, the diffusion coefficients and effective porosities of HDO and Cl were almost the same; it was thus difficult to assess the component separation by diffusion. However, isotope fractionation of Cl and Br was confirmed using a through-diffusion experiment. The results show that HDO and Cl separation and isotope fractionation of Cl and Br can be expected in diffusion-dominant domains in geological formations
Effects of TiO2 and ZnO nanoparticles on the growth of phytoplankton assemblages in seawater
Compounds in sunscreen such as ultraviolet (UV) filters protect human skin from damage caused by UV radiation exposure. However, sunscreen components reach marine ecosystems after their release from human skin during activities such as swimming and washing, and are potentially toxic to marine organisms. TiO2 and ZnO nanoparticles (NPs) are commonly used as inorganic UV filters. In this study, we explored the effects of TiO2 and ZnO NPs on natural phytoplankton assemblages in coastal seawater. Growth rates of natural phytoplankton assemblages were significantly decreased by 10 mg L−1 TiO2 and 1 and 10 mg L−1 ZnO NP treatments. NP addition also modified the size structure of phytoplankton assemblages, and small phytoplankton (mainly cyanobacteria) are vulnerable to NPs. Because herbivore food preferences depend strongly on algal cell size, NP contamination could also affect higher trophic levels. Notably, small phytoplankton are an important component in microbial loop, and this energy transfer pathway may be more vulnerable to NP contamination