Filters








92 Hits in 1.1 sec

Establishment of a Healthcare System for Patients With Adult Congenital Heart Disease in Collaboration With Children's Hospital ― The Nagano Model ―

Hirohiko Motoki, Satoshi Yasukochi, Kiyohiro Takigiku, Kohta Takei, Toru Okamura, Kazuhiro Kimura, Masatoshi Minamisawa, Ayako Okada, Tatsuya Saigusa, Soichiro Ebisawa, Tatsuichiro Seto, Morio Shoda (+2 others)
2019 Circulation Journal  
This study presents the process of establishing an ACHD care system as a collaborative effort between Shinshu University Hospital and Nagano Children's Hospital.  ...  Methods Nagano Model The Nagano model is a regional healthcare system for ACHD in our prefecture.  ...  Conclusions The ACHD care system has been launched in Nagano.  ... 
doi:10.1253/circj.cj-18-0705 pmid:30568052 fatcat:gxqxoovjuna27l572q2uhejyzy

Dynamic Mapping of Subarctic Surface Water by Fusion of Microwave and Optical Satellite Data Using Conditional Adversarial Networks

Hiroki Mizuochi, Yoshihiro Iijima, Hirohiko Nagano, Ayumi Kotani, Tetsuya Hiyama
2021 Remote Sensing  
Surface water monitoring with fine spatiotemporal resolution in the subarctic is important for understanding the impact of climate change upon hydrological cycles in the region. This study provides dynamic water mapping with daily frequency and a moderate (500 m) resolution over a heterogeneous thermokarst landscape in eastern Siberia. A combination of random forest and conditional generative adversarial networks (pix2pix) machine learning (ML) methods were applied to data fusion between the
more » ... erate Resolution Imaging Spectroradiometer (MODIS) and the Advanced Microwave Scanning Radiometer 2, with the addition of ancillary hydrometeorological information. The results show that our algorithm successfully filled in observational gaps in the MODIS data caused by cloud interference, thereby improving MODIS data availability from 30.3% to almost 100%. The water fraction estimated by our algorithm was consistent with that derived from the reference MODIS data (relative mean bias: −2.43%; relative root mean squared error: 14.7%), and effectively rendered the seasonality and heterogeneous distribution of the Lena River and the thermokarst lakes. Practical knowledge of the application of ML to surface water monitoring also resulted from the preliminary experiments involving the random forest method, including timing of the water-index thresholding and selection of the input features for ML training.
doi:10.3390/rs13020175 fatcat:hcrb7oehkvdf5jsjzc7ldyxd2u

Effects of water vapor dilution on trace gas flux, and practical correction methods

Yoshinobu HARAZONO, Hiroki IWATA, Ayaka SAKABE, Masahito UEYAMA, Kenshi TAKAHASHI, Hirohiko NAGANO, Taro NAKAI, Yoshiko KOSUGI
2015 Journal of Agricultural Meteorology  
., 1991; Nagano et al., 2012) .  ...  We examined the correction of H 2 O dilution for CH 4 flux measurements by static closed chamber method at the Eurasian steppe of southwestern Russia (Nagano et al., 2012) .  ... 
doi:10.2480/agrmet.d-14-00003 fatcat:onf5cjjgazdvtp6dykkcnd44pm

In Situ Observations Reveal How Spectral Reflectance Responds to Growing Season Phenology of an Open Evergreen Forest in Alaska

Hideki Kobayashi, Shin Nagai, Yongwon Kim, Wei Yang, Kyoko Ikeda, Hiroki Ikawa, Hirohiko Nagano, Rikie Suzuki
2018 Remote Sensing  
Plant phenology timings, such as spring green-up and autumn senescence, are essential state information characterizing biological responses and terrestrial carbon cycles. Current efforts for the in situ reflectance measurements are not enough to obtain the exact interpretation of how seasonal spectral signature responds to phenological stages in boreal evergreen needleleaf forests. This study shows the first in situ continuous measurements of canopy scale (overstory + understory) and understory
more » ... spectral reflectance and vegetation index in an open boreal forest in interior Alaska. Two visible and near infrared spectroradiometer systems were installed at the top of the observation tower and the forest understory, and spectral reflectance measurements were performed in 10 min intervals from early spring to late autumn. We found that canopy scale normalized difference vegetation index (NDVI) varied with the solar zenith angle. On the other hand, NDVI of understory plants was less sensitive to the solar zenith angle. Due to the influence of the solar geometry, the annual maximum canopy NDVI observed in the morning satellite overpass time (10-11 am) shifted to the spring direction compared with the standardized NDVI by the fixed solar zenith angle range (60−70 • ). We also found that the in situ NDVI time-series had a month-long high NDVI plateau in autumn, which was completely out of photosynthetically active periods when compared with eddy covariance net ecosystem exchange measurements. The result suggests that the onset of an autumn high NDVI plateau is likely to be the end of the growing season. In this way, our spectral measurements can serve as baseline information for the development and validation of satellite-based phenology algorithms in the northern high latitudes.
doi:10.3390/rs10071071 fatcat:2vsu5wdoj5aqvpv5uhachnbl3a

Leaf- and ecosystem-scale photosynthetic parameters for the overstory and understory of boreal forests in interior Alaska

Masahito UEYAMA, Narumi TAHARA, Hirohiko NAGANO, Naoki MAKITA, Hiroki IWATA, Yoshinobu HARAZONO
2018 Journal of Agricultural Meteorology  
Photosynthetic parameters are key for predicting the carbon cycle and fluxes in terrestrial ecosystems. In northern high-latitude regions where cold temperatures limit available nitrogen for plants, the photosynthetic parameters are tightly linked with the nitrogen content. Here, we present the leaf-and ecosystem-scale photosynthetic parameters, the maximum carboxylation rate vcmax25 , based on leaf chamber measurements and eddy covariance data from two mature black spruce forests and one young
more » ... aspen-birth forest in interior Alaska. The leaf carbon to nitrogen ratio C:N ratio explained most of the variations in vcmax25 across the five vascular plants Picea mariana, Betula glandulosa, Ledum groenlandicum, Betula papyrifera, and Populus tremuloides R 2 0. 68; p 0. 01 , including the overstory and understory, from the three forests. Each plant had a small within-species variability of vcmax25 and leaf C:N, suggesting that plants have a specific potential for available N in photosynthesis. This result indicates that the canopy structure and community composition are presumably important factors for modeling the canopy photosynthesis across boreal forests in interior Alaska. The ecosystem-scale vcmax25 determined from the eddy covariance data further supported this hypothesis.
doi:10.2480/agrmet.d-17-00031 fatcat:aqquvk7cxvbhdir6m3scikqtr4

Methane exchange in a poorly-drained black spruce forest over permafrost observed using the eddy covariance technique

Hiroki Iwata, Yoshinobu Harazono, Masahito Ueyama, Ayaka Sakabe, Hirohiko Nagano, Yoshiko Kosugi, Kenshi Takahashi, Yongwon Kim
2015 Agricultural and Forest Meteorology  
15 Ecosystem-scale methane (CH 4 ) exchange was observed in a poorly-drained 16 black spruce forest over permafrost in interior Alaska during the snow-free 17 seasons of 2011-2013, using the eddy covariance technique. The magnitude 18 of average CH 4 exchange differed depending on wind direction, reflecting spa-19 tial variation in soil moisture condition around the observation tower, due 20 to elevation change within the small catchment. In the drier upper posi-21 tion, the seasonal variation
more » ... n CH 4 emission was explained by the variation 22 in soil water content only. In the wetter bottom, however, in addition to 23 soil temperature and soil water content, seasonal thaw depth of frozen soil 24 was also an important variable explaining the seasonal variation in CH 4 ex-25 change for this ecosystem. Total snow-free season (day of year 134-280) CH 4 26 exchanges were 12.0 ± 1.0, 19.6 ± 3.0, and 36.6 ± 4.4 mmol m −2 season −1 for 27 * Corresponding author. Hiroki Iwata the drier upper position, moderately wet area, and wetter bottom of the 28 catchment, respectively. Observed total season CH 4 emission was nearly one 29 order smaller than those reported in other northern wetlands, due proba-30 bly to the relatively low ground water level and low soil temperature. The 31 interannual variation of total snow-free season CH 4 emission in the wetter 32 bottom of the catchment was influenced by the amount of rainfall and thaw 33 depth. On the other hand, in the drier upper position the amount of rainfall 34 did not strongly affect the total season CH 4 emission. Different responses of 35 CH 4 exchange to seasonal change in environmental conditions, depending on 36 the position of a small catchment, should be considered when estimating the 37 spatial variation in CH 4 exchange accurately in ecosystems over permafrost. 38
doi:10.1016/j.agrformet.2015.08.252 fatcat:ow4bcn5uevgkfmmg3oqqus7oau

Understory CO2, sensible heat, and latent heat fluxes in a black spruce forest in interior Alaska

Hiroki Ikawa, Taro Nakai, Robert C. Busey, Yongwon Kim, Hideki Kobayashi, Shin Nagai, Masahito Ueyama, Kazuyuki Saito, Hirohiko Nagano, Rikie Suzuki, Larry Hinzman
2015 Agricultural and Forest Meteorology  
21 An open black spruce forest, the most common ecosystem in interior Alaska, is characterized by 22 patchy canopy gaps where the forest understory is exposed. This study measured CO2, sensible 23 heat, and latent heat fluxes with eddy covariance (EC) in one of those large canopy gaps, and 24 estimated understory fluxes in a black spruce forest in 2011 -2014. Then understory fluxes and 25 ecosystem fluxes were compared. The understory fluxes during the snow-free seasons were 26 determined by
more » ... approaches. The first approach determined understory fluxes as the fluxes 27 from the canopy gap, assuming that fluxes under the canopy crown also had the same magnitude 28 as the canopy gap fluxes. The second approach determined the understory fluxes by scaling 29 canopy gap fluxes with a canopy gap fraction, assuming that only canopy gaps, which mostly 30 constitutes the forest floor, contribute to fluxes. The true understory fluxes would be in between 31 these two estimates. Overall, the understory accounted for 53 (39 -66) %, 61 (45 -77) %, 63 32 (45 -80) %, 73 (56 -90) %, and 79 (59 -98) % of the total net ecosystem productivity (NEP), 33 gross primary productivity (GPP), ecosystem respiration (RE), sensible heat flux (H), and latent 34 heat flux (LE), respectively. The ratio of understory NEP (NEPU) to the ecosystem NEP (NEPE) 35 and similarly calculated LEU/LEE during the daytime increased with vapor pressure deficit 36 (VPD) at low VPD conditions (~ 2000 Pa) at half-hourly temporal scale. At high VPD 37 conditions, however, NEPU/NEPE decreased with VPD, whereas LEU/LEE was maintained at the 38 high level even at high VPD conditions. Despite large ranges of the estimates for the understory 39 contributions, we conclude that the understory plays an important role in the carbon and energy 40 balances of the black spruce ecosystem, and their contribution highly depends on the level of 41 VPD. 42
doi:10.1016/j.agrformet.2015.08.247 fatcat:htadillnyvfxtnlb4tn2ywfurq

Links between annual surface temperature variation and land cover heterogeneity for a boreal forest as characterized by continuous, fibre-optic DTS monitoring

Kazuyuki Saito, Go Iwahana, Hiroki Ikawa, Hirohiko Nagano, Robert Busey
2018 Geoscientific Instrumentation Methods and Data Systems Discussions  
A fibre-optic DTS (distributed temperature sensing) system using Raman-scattering optical time domain reflectometry was deployed to monitor a boreal forest research site in the interior of Alaska. Surface temperatures range between −40 ºC in winter to 30 ºC in summer at this site. In parallel experiments, a fibre-optic cable sensor system (multi-mode, GI50/125, dual core; 3.4 mm) monitored at high-resolution (0.5-metre intervals every
more » ... tes) ground surface across the landscape and, at several points a high resolution vertical profile from the upper subsurface to a meter above. The total cable ran 2.7 km with about 2.0 km monitoring a horizontal surface path. Sections of the cable sensor were deployed in vertical coil configurations (1.2 m high) to measure vertical temperature profiles from the ground up at 5-mm intervals. Measurements were collected continuously over a two year interval from October, 2012 to October, 2014. Vegetation of the overall site (Poker Flat Research Range) consists primarily of black spruce underlain by permafrost. Land cover types within the study area were classified into six descriptive categories: relict thermokarst lake, open moss, shrub, deciduous forest, sparse conifer forest, and dense conifer forest. The horizontal temperature data exhibited spatio-temporal patterns within the observed diurnal and seasonal variation. Differences in snow pack evolution and insulation effects co-varied with the land cover types. The apparatus used to monitor vertical temperature profiles generated high-resolution (c. 5 mm) data for air column, snow cover, and ground surface. This research also identified several technical challenges of deploying and maintaining a DTS system in sub-arctic environments.
doi:10.5194/gi-2018-8 fatcat:z6btiwinlngs7npxlnwjbi3lwu

Optimization of a biochemical model with eddy covariance measurements in black spruce forests of Alaska for estimating CO2 fertilization effects

Masahito Ueyama, Narumi Tahara, Hiroki Iwata, Eugénie S. Euskirchen, Hiroki Ikawa, Hideki Kobayashi, Hirohiko Nagano, Taro Nakai, Yoshinobu Harazono
2016 Agricultural and Forest Meteorology  
26 Understanding how high-latitude terrestrial productivity and evapotranspiration 27 change in association with rising atmospheric CO 2 concentration ([CO 2 ]), also known as 28 'CO 2 fertilization', is important for predicting future climate change. To quantify the 29 magnitude of this fertilization effect, we have developed a big-leaf model that couples 30 photosynthesis and stomatal conductance processes. This model was inverted by 31 inputting eddy covariance CO 2 and H 2 O fluxes from
more » ... black spruce forests in Alaska 32 to infer spatially representative ecophysiological parameters using a global optimization 33 technique. Inferred seasonal variations in a maximum carboxylation rate at 25 o C per 34 unit leaf area and stomatal conductance suggest greater photosynthetic capacity per unit 35 leaf area during the mid-growing season, compared to spring and autumn. The 36 interannual variability of parameters suggest that warm summers stimulate 37 photosynthetic capacity and dry summers force stomatal regulation. Based on the model 38 with optimized parameters, small but clear increases in gross primary productivity 39 (GPP) and decreases in latent heat flux (LE) were estimated to be associated with rising 40 [CO 2 ] from 2002 to 2014 (p < 0.01). With a 23 ppm increase in summertime (June -41 August) [CO 2 ] from 2002 to 2014, the rates of increase per unit [CO 2 ] were 42 approximately 0.16 ± 0.04 % ppm -1 for GPP and -0.06 ± 0.03 % ppm -1 for LE from 43 2002 to 2014. However, considerable uncertainties (greater than 100%) were estimated 44 in the magnitude of the fertilization effect associated with different parameterizations in 45 the biochemical model, indicating the need for ecophysiological studies for boreal 46
doi:10.1016/j.agrformet.2016.03.007 fatcat:ejb3un6rwjcqhklwqeoxjv4toa

Links between annual surface temperature variation and land cover heterogeneity for a boreal forest as characterized by continuous, fibre-optic DTS monitoring

Kazuyuki Saito, Go Iwahana, Hiroki Ikawa, Hirohiko Nagano, Robert C. Busey
2018 Geoscientific Instrumentation, Methods and Data Systems  
., 2015; Nagano et al., 2018) .  ... 
doi:10.5194/gi-7-223-2018 fatcat:ljs6blahi5e7jfai2pwdj2reoe

Effect of Addition Elements on Creep Properties of the Sn-Ag-Cu Lead Free Solder
Sn‐Ag‐Cu系鉛フリーはんだのクリープ特性における微量添加元素の影響

Megumi NAGANO, Noboru HIDAKA, Hirohiko WATANABE, Masayoshi SHIMODA, Masahiro ONO
2006 Journal of The Japan Institute of Electronics Packaging  
Creep properties of two lead-free solder alloys, Sn-3.5Ag-0.5Cu-Ni-Ge and Sn-3.0Ag-0.5Cu, were investigated at temperatures between 40•Ž and 125•Ž. It is found that the creep strength of Sn-3.5Ag-0.5Cu-Ni-Ge solder is better than that of Sn-3.0Ag-0.5Cu solder. Especially in the low stress region at 125•Ž, the creep rupture time of Sn-3.5Ag-0.5Cu-Ni-Ge solder is about three times longer than that of Sn-3.0Ag-0.5Cu solder. Microstructure characterizations, including TEM analysis, were conducted
more » ... order to fully describe the creep properties of the lead-free solders.
doi:10.5104/jiep.9.171 fatcat:uiyzmg2wync2jby7uoiefsrx44

Latitudinal gradient of spruce forest understory and tundra phenology in Alaska as observed from satellite and ground-based data

Hideki Kobayashi, Ali P. Yunus, Shin Nagai, Konosuke Sugiura, Yongwon Kim, Brie Van Dam, Hirohiko Nagano, Donatella Zona, Yoshinobu Harazono, M. Syndonia Bret-Harte, Kazuhito Ichii, Hiroki Ikawa (+4 others)
2016 Remote Sensing of Environment  
The latitudinal gradient of the start of the growing season (SOS) and the end of the growing season (EOS) were quantified in Alaska (61°N to 71°N) using satellite-based and ground-based datasets. The Alaskan evergreen needleleaf forests are sparse and the understory vegetation has a substantial impact on the satellite signal. We evaluated SOS and EOS of understory and tundra vegetation using time-lapse camera images. From the comparison of three SOS algorithms for determining SOS from two
more » ... ite datasets (SPOT-VEGETATION and Terra-MODIS), we found that the satellite-based SOS timing was consistent with the leaf emergence of the forest understory and tundra vegetation. The ensemble average of SOS over all satellite algorithms can be used as a measure of spring leaf emergence for understory and tundra vegetation. In contrast, the relationship between the groundbased and satellite-based EOSs was not as strong as that of SOS both for boreal forest and tundra sites because of the large biases between those two EOSs (19 to 26 days). The satellite-based EOS was more relevant to snowfall events than the senescence of understory or tundra. The plant canopy radiative transfer simulation suggested that 84-86% of the NDVI seasonal amplitude could be a reasonable threshold for the EOS determination. The latitudinal gradients of SOS and EOS evaluated by the satellite and ground data were consistent and the satellitederived SOS and EOS were 3.5 to 5.7 days degree −1 and −2.3 to −2.7 days degree −1 , which corresponded to the spring (May) temperature sensitivity of −2.5 to −3.9 days°C −1 in SOS and the autumn (August and September) temperature sensitivity of 3.0 to 4.6 days°C −1 in EOS. This demonstrates the possible impact of phenology in spruce forest understory and tundra ecosystems in response to climate change in the warming Artic and sub-Arctic regions.
doi:10.1016/j.rse.2016.02.020 fatcat:rtkypn7xhzb63no2y6bwi3q3ha

Renoprotective Effect of the Addition of Losartan to Ongoing Treatment with an Angiotensin Converting Enzyme Inhibitor in Type-2 Diabetic Patients with Nephropathy

Hirohiko ABE, Shinya MINATOGUCHI, Hiroshige OHASHI, Ichijiro MURATA, Taro MINAGAWA, Toshio OKUMA, Hitomi YOKOYAMA, Hisato TAKATSU, Tadatake TAKAYA, Toshihiko NAGANO, Yukio OSUMI, Masao KAKAMI (+4 others)
2007 Hypertension Research  
Angiotensin converting enzyme inhibitors (ACE-Is) and angiotensin II receptor blockers (ARBs) are fre- quently used for the treatment for glomerulonephritis and diabetic nephropathy because of their albuminuria-or proteinuria-reducing effects. To many patients who are nonresponsive to monotherapy with these agents, combination therapy appears to be a good treatment option. In the present study, we examined the effects of the addition of an ARB (losartan) followed by titration upon addition and
more » ... t 3 and 6 months (n =14) and the addition of an ACE-I followed by titration upon addition and at 3 and 6 months (n =20) to the drug regimen treatment protocol in type 2 diabetic patients with nephropathy for whom more than 3-month administration of an ACE-I or the combination of an ACE-I plus a conventional antihypertensive was ineffective to achieve a blood pressure (BP) of 130/80 mmHg and to reduce urinary albumin to <30 mg/day. During the 12-month treatment, addition of losartan or addition of an ACE-I to the treatment protocol reduced systolic blood pressure (SBP) by 10% and 12%, diastolic blood pressure (DBP) by 7% and 4%, and urinary albumin excretion by 38% and 20% of the baseline value, respectively. However, the effects on both BP and urinary albumin were not significantly different between the two therapies. In conclusion, addition of losartan or an ACE-I to an ongoing treatment with an ACE-I, or addition of an ACE-I to ongoing treatment with a conventional antihypertensive were equally effective at reducing the urinary albumin excretion and BP, and provided renal protection in patients with type-2 diabetic nephropathy. (Hypertens Res 2007; 30: 929-935) Key Words: albuminuria, angiotensin converting enzyme inhibitor, angiotensin II receptor blocker, diabetic nephropathy From the
doi:10.1291/hypres.30.929 pmid:18049024 fatcat:73uc4nxcbnbsbnfcyifeqxswaq

Progress of cBN Abrasive and Grinding Technology
次世代超硬質材料の超高圧合成とナノ組織制御 cBN砥粒と研削技術の進展

Hirohiko OHTSUBO
2003 The Review of High Pressure Science and Technology  
cBN Progress of cBN Abrasive and Grinding Technology Hirohiko OHTSUBO This paper reviews the developments achieved to date in cBN abrasive technology and explores progress expected in the near future.  ...  : CBN , 200 (1991) . [3] : 43, 8, 5-9 (1999). [4] : 43, 14-17 (1999) . [5] : 43, 18-21 (1999 Group 1 Ceramics Division Shiojiri Plant SHOWA DENKO K.K. 1, Oaza Soga, Shiojiri, Nagano 399-6461  ... 
doi:10.4131/jshpreview.13.4 fatcat:b26b5p6pfbcelojsduowppg35e

23-11 ロシア、ウラル山脈南部のアルカイムにおける温室効果ガスの動態と土壌微生物性 : 耕作履歴や土壌年代の違いが及ぼす影響(23.地球環境,2010年度北海道大会)
23-11 Greenhouse gaseous dynamics and soil microbial properties in soils of Arkaim, south Urals, Russia : Effects of agricultural history and soil age

Hirohiko Nagano, So Sugihara, Miwa Matsushima, Valentina E. Prikhodko, Elena Manakhova, Gennady B. Zdanovich, Dmitry G. Zdanovich, Shinya Funakawa, Masayuki Kawahigashi, Kazuyuki Inubushi
2010 Abstracts of the Annual Meetings, Japanese Society of Soil Science and Plant Nutrition  
Hirohiko 巨 ・ Sugihara So2 ・ Matsushima Miwai ・ Prikhodko 、 厂 alentina E. 3 ・ Manakhova Elena4 Zdanovich Gennady B . 4 ・ Zdanovich Dmitry G. ' ・ Funakawa Shinya2 ・ Kawahigashi Masayuki5 ・ 王 nubushi Kazuyuki1  ...  soils of Arkaim, south Ura 玉 s, Russia − Effects of agriculturai history and soil age 一 ロ シ ア 、 ウ ラ ル 山 脈 南 部 の ア ル カ イ ム に お け る 温 室 効 果 ガ ス の 動 態 と土 壌 微 生 物 性 一 耕 作 履 歴 や 土 壌 年 代 の 違 い が 及 ぼ す 影 響 一 〇 Nagano  ... 
doi:10.20710/dohikouen.56.0_179_2 fatcat:3e25uxm3zvaw3gusfjax7qfum4
« Previous Showing results 1 — 15 out of 92 results