Estimation of the Number of Sampling Points Required for the Determination of Soil CO2 Efflux in Two Types of Plantation in a Temperate Region

이나연,Hiroshi Koizumi 한국생태학회 2009 Journal of Ecology and Environment Vol.32 No.2

Soil CO2 efflux can vary markedly in magnitude over both time and space, and understanding this variation is crucial for the correct measurement of CO2 efflux in ecological studies. Although considerable research has quantified temporal variability in this flux, comparatively little effort has focused on its spatial variability. To account for spatial heterogeneity, we must be able to determine the number of sampling points required to adequately estimate soil CO2 efflux in a target ecosystem. In this paper, we report the results of a study of the number of sampling points required for estimating soil CO2 efflux using a closed-dynamic chamber in young and old Japanese cedar plantations in central Japan. The spatial heterogeneity in soil CO2 efflux was significantly higher in the mature plantation than in the young stand. In the young plantation, 95% of samples of 9 randomly-chosen flux measurements from a population of 16 measurements made using 72-cm2 chambers produced flux estimates within 20% of the full-population mean. In the mature plantation, 20 sampling points are required to achieve means within ± 20% of the full-population mean (15 measurements) for 95% of the sample dates. Variation in soil temperature and moisture could not explain the observed spatial variation in soil CO2 efflux, even though both parameters are a good predictor of temporal variation in CO2 efflux. Our results and those of previous studies suggest that, on average, approximately 46 sampling points are required to estimate the mean and variance of soil CO2 flux in temperate and boreal forests to a precision of ± 10% at the 95% confidence level, and 12 points are required to achieve a precision of ± 20%. Soil CO2 efflux can vary markedly in magnitude over both time and space, and understanding this variation is crucial for the correct measurement of CO2 efflux in ecological studies. Although considerable research has quantified temporal variability in this flux, comparatively little effort has focused on its spatial variability. To account for spatial heterogeneity, we must be able to determine the number of sampling points required to adequately estimate soil CO2 efflux in a target ecosystem. In this paper, we report the results of a study of the number of sampling points required for estimating soil CO2 efflux using a closed-dynamic chamber in young and old Japanese cedar plantations in central Japan. The spatial heterogeneity in soil CO2 efflux was significantly higher in the mature plantation than in the young stand. In the young plantation, 95% of samples of 9 randomly-chosen flux measurements from a population of 16 measurements made using 72-cm2 chambers produced flux estimates within 20% of the full-population mean. In the mature plantation, 20 sampling points are required to achieve means within ± 20% of the full-population mean (15 measurements) for 95% of the sample dates. Variation in soil temperature and moisture could not explain the observed spatial variation in soil CO2 efflux, even though both parameters are a good predictor of temporal variation in CO2 efflux. Our results and those of previous studies suggest that, on average, approximately 46 sampling points are required to estimate the mean and variance of soil CO2 flux in temperate and boreal forests to a precision of ± 10% at the 95% confidence level, and 12 points are required to achieve a precision of ± 20%.

MAGNETIC PROPERTIES OF Co - FERRITE FILMS BY SOLID REACTION AT LOW TEMPERATURE

Masafumi CHIBA,Chikao UEMURA,Hiroshi ARIMA,Yoshiharu KOIZUMI 한국자기학회 1995 韓國磁氣學會誌 Vol.5 No.5

Co-ferrite (CoO-Fe₂O₃) thin films have been prepared by two ways of low temperature solid reaction including oxidation process, being based on Co-layer/α-Fe₂O₃ films and Co-layer/Fe₂O₃ films. Magnetic properties of both Co-ferrite films have been measured and compared. The samples from Co-layer/Fe₃O₄ films have a large coercive force in the direction perpendicular and have a great poler kerr rotation angle at wavelength 700 ㎚ than ones from Co-layer/α-Fe₂O₃ films. The typical magnetic properties are as follows; saturation magnetization 4πMs, 2.9 kG; remnant magnetization 4πMr, 2.0 kG; coercive force Hc, 4.0 kOe; kerr rotation angle Φk, 0.39 deg (λ = 700 ㎚); and initial magnetization energy E, 3.3×10^6 erg/㎤, respectively.

Lymphopenia and Elevated Blood C-Reactive Protein Levels at Four Days Postoperatively Are Useful Markers for Early Detection of Surgical Site Infection Following Posterior Lumbar Instrumentation Surgery

Eiichiro Iwata,Hideki Shigematsu,Munehisa Koizumi,Hiroshi Nakajima,Akinori Okuda,Yasuhiko Morimoto,Keisuke Masuda,Yasuhito Tanaka 대한척추외과학회 2016 Asian Spine Journal Vol.10 No.2

Study Design: Case-control study. Purpose: To identify the characteristics of candidate indexes for early detection of surgical site infection (SSI). Overview of Literature: SSI is a serious complication of spinal instrumentation surgery. Early diagnosis and treatment are crucial for the welfare of the patient postoperation. Methods: We retrospectively reviewed laboratory data of patients who underwent posterior lumbar instrumentation surgery for degenerative spine disease. The sensitivity and specificity of six laboratory markers for early detection of SSI were calculated: greater elevation of the white blood cell count at day 7 than at day 4 postoperatively, greater elevation of the C-reactive protein (CRP) level at day 7 than at day 4 postoperatively, a CRP level of >10 mg/dL at 4 days postoperatively, neutrophil percentage of >75% at 4 days postoperatively, a lymphocyte percentage of <10% at 4 days postoperatively, and a lymphocyte count of <1,000/μL at 4 days postoperatively. Statistical analysis was via Fisher’s exact test and a p -value of <0.05 was considered significant. Results: In total, 85 patients were enrolled. Of these, five patients developed deep SSI. The sensitivity and specificity of each index were as follows: index 1, 20.0% and 77.5%; index 2, 20.0% and 83.8%; index 3, 40.0% and 97.5%; index 4, 40.0% and 86.3%; index 5, 0% and 96.3%; and index 6, 80.0% and 80.0%. A significant difference was noted for indexes 3 and 6. Conclusions: A CRP level of >10 mg/dL at 4 days postoperatively would be useful for definitive diagnosis of SSI, and a lymphocyte count of <1,000/μL at 4 days postoperatively would be a useful screening test for SSI. Although laboratory markers for early detection of SSI have been frequently reported, we believe that it is important to understand the characteristics of each index for a precise diagnosis.

Estimation of the Number of Sampling Points Required for the Determination of Soil CO₂ Efflux in Two Types of Plantation in a Temperate Region

Lee, Na-Yeon(Mi-Sun),Koizumi, Hiroshi The Ecological Society of Korea 2009 Journal of Ecology and Environment Vol.32 No.2

Soil $CO_2$ efflux can vary markedly in magnitude over both time and space, and understanding this variation is crucial for the correct measurement of $CO_2$ efflux in ecological studies. Although considerable research has quantified temporal variability in this flux, comparatively little effort has focused on its spatial variability. To account for spatial heterogeneity, we must be able to determine the number of sampling points required to adequately estimate soil $CO_2$ efflux in a target ecosystem. In this paper, we report the results of a study of the number of sampling points required for estimating soil $CO_2$ efflux using a closed-dynamic chamber in young and old Japanese cedar plantations in central Japan. The spatial heterogeneity in soil $CO_2$ efflux was significantly higher in the mature plantation than in the young stand. In the young plantation, 95% of samples of 9 randomly-chosen flux measurements from a population of 16 measurements made using 72-$cm^2$ chambers produced flux estimates within 20% of the full-population mean. In the mature plantation, 20 sampling points are required to achieve means within $\pm$ 20% of the full-population mean (15 measurements) for 95% of the sample dates. Variation in soil temperature and moisture could not explain the observed spatial variation in soil $CO_2$ efflux, even though both parameters are a good predictor of temporal variation in $CO_2$ efflux. Our results and those of previous studies suggest that, on average, approximately 46 sampling points are required to estimate the mean and variance of soil $CO_2$ flux in temperate and boreal forests to a precision of $\pm$ 10% at the 95% confidence level, and 12 points are required to achieve a precision of $\pm$ 20%.

Seasonal variability of soil respiration in multiple ecosystems under the same physical–geographical environmental conditions in central Japan

Tomoharu Inoue,Shin Nagai,Shota Inoue,Masahiro Ozaki,Shohei Sakai,Hiroyuki Muraoka,Hiroshi Koizumi 한국산림과학회 2012 Forest Science And Technology Vol.8 No.2

We investigated the relationships between soil respiration and environmental factors during foliation and defoliation periods in three ecosystems under the same physical–geographical environmental conditions in central Japan. These ecosystems comprised deciduous broad-leaved forest (Quercus crispula dominated, site Q), deciduous needle-leaved forest (Larix kaempferi dominated, site L), and grassland (Zoysia japonica dominated, site Z). Field measurements of soil respiration were made using a closed chamber method with an infrared gas analyzer at monthly intervals in the snow-free seasons from May 2010 to November 2011. Soil respiration began to increase in May, peaked rapidly in summer (July to September), and decreased in November. The seasonal patterns of soil respiration and soil temperature were nearly parallel among the three sites, with one exception, which may have been caused by the decrease in soil water content during summer months (July to September). Although Q_10 values based on the entire measurement period in 2010 were roughly the same as those in 2011 at the three sites, there was a large difference in Q_10 between the foliation and defoliation periods in both years, especially at the two forest sites. These differences among the three sites may be caused by differences in soil temperature dynamics and precipitation activity. To better understand the relationship between soil respiration and environmental factors, continuous observations are needed of soil respiration, environmental factors, and biological activities both below ground and above ground under the same physical–geographical environmental conditions.

Oral Administration of Collagen Hydrolysates Improves Glucose Tolerance in Normal Mice Through GLP-1-Dependent and GLP-1-Independent Mechanisms

Yoshinori Iba,Koji Yokoi,Itsuka Eitoku,Masaki Goto,Seiko Koizumi,Fumihito Sugihara,Hiroshi Oyama,Tadashi Yoshimoto 한국식품영양과학회 2016 Journal of medicinal food Vol.19 No.9

The aim of this study was to evaluate the antidiabetic properties of collagen hydrolysates (CHs). CHs exhibited dipeptidyl peptidase-IV inhibitory activity and stimulated glucagon-like-peptide-1 (GLP-1) secretion in vitro. We also determined whether CHs improve glucose tolerance in normal mice. Oral administration of CHs suppressed the glycemic response during the oral and intraperitoneal glucose tolerance tests (OGTT and IPGTT), but the effects were weaker in IPGTT than in OGTT. CHs had no effect on the gastric emptying rate. A pretreatment with the GLP-1 receptor antagonist, exendin 9–39 (Ex9), partially reversed the glucose-lowering effects of CHs, but only when coadministered with glucose. CHs administered 45 min before the glucose load potentiated the glucose-stimulated insulin secretion. This potentiating effect on insulin secretion was not reversed by the pretreatment with Ex9, it appeared to be enhanced. These results suggest that CHs improve glucose tolerance by inhibiting intestinal glucose uptake and enhancing insulin secretion, and also demonstrated that GLP-1 was partially involved in the inhibition of glucose uptake, but not essential for the enhancement of insulin secretion.

Lymphopenia at 4 Days Postoperatively Is the Most Significant Laboratory Marker for Early Detection of Surgical Site Infection Following Posterior Lumbar Instrumentation Surgery

Eiichiro Iwata,Hideki Shigematsu,Akinori Okuda,Yasuhiko Morimoto,Keisuke Masuda,Hiroshi Nakajima,Munehisa Koizumi,Yasuhito Tanaka 대한척추외과학회 2016 Asian Spine Journal Vol.10 No.6

Study Design: Case control study. Purpose: To identify the most significant laboratory marker for early detection of surgical site infection (SSI) using multiple logistic regression analysis. Overview of Literature: SSI is a serious complication of spinal instrumentation surgery. Early diagnosis and treatment are crucial. Methods: We retrospectively reviewed the laboratory data of patients who underwent posterior lumbar instrumentation surgery for degenerative spinal disease from January 2003 to December 2014. Six laboratory markers for early SSI detection were considered: renewed elevation of the white blood cell count, higher at 7 than 4 days postoperatively; renewed elevation of the C-reactive protein (CRP) level, higher at 7 than 4 days postoperatively; CRP level of >10 mg/dL at 4 days postoperatively; neutrophil percentage of >75% at 4 days postoperatively; lymphocyte percentage of <10% at 4 days postoperatively; and lymphocyte count of <1,000/μL at 4 days postoperatively. Results: Ninety patients were enrolled; five developed deep SSI. Multivariate regression analysis showed that a lymphocyte count of <1,000/μL at 4 days postoperatively was the sole significant independent laboratory marker for early detection of SSI (p =0.037; odds ratio, 11.9; 95% confidence interval, 1.2–122.7). Conclusions: A lymphocyte count of <1,000/μL at 4 days postoperatively is the most significant laboratory marker for early detection of SSI.

Cholecystitis after Placement of Covered Self-Expandable Metallic Stents in Patients with Distal Malignant Biliary Obstructions

Masafumi Watanabe,Kosuke Okuwaki,Jun Woo,Mitsuhiro Kida,Hiroshi Imaizumi,Tomohisa Iwai,Hiroshi Yamauchi,Toru Kaneko,Rikiya Hasegawa,Takahiro Kurosu,Naoki Minato,Hiroki Haradome,Wasaburo Koizumi 대한소화기내시경학회 2021 Clinical Endoscopy Vol.54 No.4

Background/Aims: Cholecystitis can occur after the placement of covered self-expandable metallic stents for distal malignant biliaryobstructions. We aimed to identify risk factors for cholecystitis following covered self-expandable metallic stent placement. Methods: We investigated risk factors related to cholecystitis following covered self-expandable metallic stent placement in 118patients with distal malignant biliary obstructions between January 1, 2015 and April 30, 2019. Endoscopic assessments and tumorinvasion to the arteries feeding the gallbladder were determined by a pancreaticobiliary endoscopist and a radiologist, respectively. Results: The median patient age was 72 years (men, 61.0%). The flow of the contrast agent into the gallbladder and tumorinvolvement in the orifice of the cystic duct were observed in 35 (29.7%) and 35 (29.7%) patients, respectively. During theobservation period (median, 179 days), cholecystitis occurred in 18 (15.3%) patients. Multivariate analysis revealed the flow ofthe contrast agent into the gallbladder (p=0.023) and tumor involvement in the orifice of the cystic duct (p=0.005) as significantindependent risk factors associated with cholecystitis. Conclusions: The flow of the contrast agent into the gallbladder and tumor involvement in the orifice of the cystic duct are potentialindependent risk factors for cholecystitis following the placement of covered self-expandable metallic stents. A follow-up prospectivestudy is warranted to validate their influence.