Rs Rates Research Articles

Ethnic Disparities in Survival of Chronic Myeloid Leukemia

Introduction: Development of tyrosine kinase inhibitors has led to significant improvement in survival of chronic myeloid leukemia (CML) patients. We conducted this study to evaluate any ethnic disparity in CML survival. Methods: We analyzed surveillance, Epidemiology, and End Results, SEER 18 registry to compare 1 and 3 years relative survival rates of CML patients diagnosed between 2001- 2008 by ethnicity - Caucasian, African American (AA), Others (O). We analyzed survival rates by age (≤65, >65), and time periods: (2001-2004) and (2005-2008). We used SEER*Stat software to calculate Z value. Results: There were 6,306 CML patients during (2001-2008); 3,111 during (2001-2004) and 3,195 during (2005-2008). The 1-year relative survival rates among Caucasians (n=6,306), AA (n=790), and Others (n=532) were 80.0±0.5%, 83.8 ±1.4%, and 84.0±1.7% [Z value 2.43 (AA vs Caucasian), 2.15 (O vs Caucasian)] respectively. The 3 years RS rates were 65.6±0.7%, 70.2±1.8%, and 70.9 ±2.1% respectively with Z value 2.49 (AA vs Caucasian) and 2.42 (Caucasian vs O). Among younger patients (age ≤65 years, n=4,245) Caucasians had better RS compared to AA (83.1±0.7% vs 78.7±1.8%, Z value 2.24) at 3 years. There was no difference survival at 1and 3 years in older patients (age >65 years, n= 3,383). The survival rates of patients diagnosed during 2001-2004 were similar for all ethnic groups. Among patients diagnosed during 2005-2008, survival rates were significantly higher for AA versus Caucasians (1 year RS 86.6±1.8% vs 81.3±0.7%, Z value 2.45, and 3 year RS 73.8±2.4% vs 68.3±0.9%, Z value 2.20). Others also had better RS compared to Caucasians (87.1±2.1% vs 81.3±0.7%, Z value 2.22) at 1 year. There was no racial disparity in survival rates when analyzed by age (≤65 and >65) and sex at 1 and 3 years during 2001-2004 and 2005-2008. Conclusions: Our study showed that there is ethnic disparity in CML survival. Among CML patients diagnosed during 2005-2008, AA and Other races had superior survival rates compared to Caucasians. Disclosures No relevant conflicts of interest to declare.

Simulated acid rain changed the proportion of heterotrophic respiration in soil respiration in a subtropical secondary forest

Acid rain is a matter of concern in southern China. We explored how soil respiration (Rs) and heterotrophic respiration (Rh) rates changed when subjected to simulated acid rain (SAR) environment for 3 years (from March 2010 to February 2013) in a secondary forest in subtropical China. The field experiment was arranged in a split-plot design, with 4 main blocks. Each block was split into un-trenched (Rs) and trenched (Rh) treatments. Four SAR treatments of CK (control, deionized water), A1 (pH 4.0), A2 (pH 3.0), and A3 (pH 2.0) were randomly assigned in each of the Rs and Rh treatments. Soil CO2 fluxes as well as soil temperature and moisture at a depth of 5cm were measured weekly. Different SAR treatments exhibited similar seasonal patterns of Rs and Rh. Mean annual Rs rates in CK, A1, A2, and A3 plots were 878.2±100.8, 919.4±33.1, 865.6±62.5, and 925.2±20.5gCm−2yr−1, respectively, over 3 years; SAR had no significant effects on Rs. Rh, however, was significantly (P<0.05) affected by the lowest SAR pH level (A3). On overage of 3 years, annual Rh rates in CK, A1, A2 and A3 plots were 606.7±52.4, 663.5±35.5, 728.2±60.7, and 760.1±42.2gCm−2yr−1, respectively. Statistical analysis showed that SAR significantly (P<0.05) increased the proportion of Rh in Rs. The relationship between residual Rs (or Rh) based on soil temperature and observed Rs (or Rh) and soil moisture could be well fitted in a quadratic model.

Modeling spatial patterns of soil respiration in maize fields from vegetation and soil property factors with the use of remote sensing and geographical information system.

To examine the method for estimating the spatial patterns of soil respiration (Rs) in agricultural ecosystems using remote sensing and geographical information system (GIS), Rs rates were measured at 53 sites during the peak growing season of maize in three counties in North China. Through Pearson's correlation analysis, leaf area index (LAI), canopy chlorophyll content, aboveground biomass, soil organic carbon (SOC) content, and soil total nitrogen content were selected as the factors that affected spatial variability in Rs during the peak growing season of maize. The use of a structural equation modeling approach revealed that only LAI and SOC content directly affected Rs. Meanwhile, other factors indirectly affected Rs through LAI and SOC content. When three greenness vegetation indices were extracted from an optical image of an environmental and disaster mitigation satellite in China, enhanced vegetation index (EVI) showed the best correlation with LAI and was thus used as a proxy for LAI to estimate Rs at the regional scale. The spatial distribution of SOC content was obtained by extrapolating the SOC content at the plot scale based on the kriging interpolation method in GIS. When data were pooled for 38 plots, a first-order exponential analysis indicated that approximately 73% of the spatial variability in Rs during the peak growing season of maize can be explained by EVI and SOC content. Further test analysis based on independent data from 15 plots showed that the simple exponential model had acceptable accuracy in estimating the spatial patterns of Rs in maize fields on the basis of remotely sensed EVI and GIS-interpolated SOC content, with R2 of 0.69 and root-mean-square error of 0.51 µmol CO2 m−2 s−1. The conclusions from this study provide valuable information for estimates of Rs during the peak growing season of maize in three counties in North China.

The effect of fire disturbance on short-term soil respiration in typical forest of Greater Xing’an Range, China

We investigated the effect of fire disturbance on short-term soil respiration in birch (Betula platyphylla Suk.) and larch (Larix gmelinii Rupr.) forests in Greater Xing’an range, northeastern China for further understanding of its effect on the carbon cycle in ecosystems. Our study show that post-fire soil respiration rates in B. platyphylla and L. gmelinii forests were reduced by 14% and 10%, respectively. In contrast, the soil heterotrophic respiration rates in the two types of forest were similar in post-fire and control plots. After fire, the contribution of root respiration to total soil respiration was dramatically reduced. Variation in soil respiration rates was explained by soil moisture (W) and soil temperature (T) at a depth of 5 cm. Exponential regression fitted T and W models explained Rs rates in B. platyphylla control and post-fire plots (83.1% and 86.2%) and L. gmelinii control and post-fire plots (83.7% and 88.7%). In addition, the short-term temperature coefficients in B. platyphylla control and post-fire plots were 5.33 and 5, respectively, and 9.12, and 5.26 in L. gmelinii control and post-fire plots, respectively. Our results provide an empirical baseline for studying the effect of fire disturbance on soil carbon balance and estimation of soil carbon flux in boreal forest.

Soil Respiration, Nitrification, and Denitrification in a Wheat Farmland Soil under Different Managements

A field experiment was conducted during the 2010 to 2011 winter wheat–growing season to understand the soil respiration (Rs ), nitrification, and denitrification rates in winter wheat farmland soil under no-tillage (NT) treatment with rice straw incorporation. The experimental treatments include NT, NT with rice straw covers on the surface (NTS), conventional tillage (CT), and CT with straw incorporation (CTS). No-tillage and straw incorporation treatments did not change the seasonal patterns of Rs , gross nitrification (Gn), and denitrification (D) rates compared with CT. Compared with the CT treatment, the NT, NTS, and CTS treatments significantly reduced Rs (P < 0.01), and the NT and NTS treatments significantly increased Gn and D (P < 0.01). CTS also significantly increased Gn (P < 0.01) but had no significant effect on D (P > 0.05). Further analysis showed that the temperature sensitivity of soil respiration (Q 10) of CT, NT, NTS, and CTS were 4.26, 1.86, 3.25, and 2.36, respectively. Our findings suggest that, compared with CT, the NT and straw incorporation treatments reduced Rs and Q 10 and increased Gn and D.

A new estimate of global soil respiration from 1970 to 2008

Soil respiration (Rs) is one of the key processes that underline our understanding of carbon cycle in terrestrial ecosystems. Great uncertainty remains in the previous global Rs estimates with a difference of 70 Pg C a−1 between the highest and lowest estimates. Thus, the present study aimed to estimate the global annual Rs and investigate the interannual and spatial variability in global annual Rs using a semi-mechanistic, empirically-based model which included climatic factors (temperature and precipitation) and topsoil (0–20 cm) organic carbon storage. About 657 published studies of annual Rs from 147 measurement sites were included in this meta-analysis. The global data sets from 1970 to 2008 on climate, surface air temperature, and soil properties were collected. The Monte Carlo method was used to propagate the simulation errors to global Rs. The results indicated that the mean annual global Rs was 94.4 Pg C a−1, increasing at roughly 0.04 Pg C a−1 (∼0.04% a−1) from 1970 to 2008. The Rs rate increased from colder, drier and less soil carbon-rich regions to warmer, moister and more carbon-rich regions. Highest Rs rates appeared in the tropical forest, while the lowest ones were in polar and desert regions. The annual Rs correlated directly with global temperature anomalies, suggesting that the interannual variability in temperature was responsible for the interannual variations in predicted global Rs. The global Rs increased from high-latitude zones to low-latitude zones. Further studies are recommended to explore the relationship between soil respiration and vegetation characters.

Grain yield and soil respiratory response to intercropping systems on arid land

Intercropping systems have been shown to boost crop productivity and provide potential for biodiversity in the development of sustainable agriculture, but little is known about the effect of intercropping on soil respiratory responses and CO2 regulations. This study determined grain yields, soil respiration (Rs) rates and their relationships to soil temperatures (Ts), dry matter (DM) accumulation, and carbon emission (CE) for maize (Zea mays L.)–pea (Pisum sativum L.) and maize–wheat (Triticum aestivum L.) intercropping, in comparison with sole pea, sole wheat, and sole maize, in an arid environment. Field experiments were conducted at Wuwei Experimental Station in 2009–2011. Maize produced the greatest grain yield at 11,724kgha−1, followed by wheat averaging at 6467kgha−1, and pea the lowest at 2830kgha−1. Sole maize had the grain yield decreased from 12,677kgha−1 in 2009 to 10,624kgha−1 in 2011, or by 19%, whereas the maize in the maize–wheat intercropping had its grain yield increased from 7404kgha−1 in 2009 to 8123kgha−1 in 2011, or by 10%. Maize-based intercropping had significant yield advantages over sole wheat and sole pea, with maize–wheat and maize–pea having land equivalent ratio of 1.2–1.5. Diurnal Rs had a single peak occurring from 12:00 to 14:00h during a day, whereas seasonal Rs changed from seedling to maturity with Rs reaching the peak in June or July. A quadratic function for DM combined with an exponential function for Ts was used to fit the measured results, showing the combination of DM and Ts accounted for 24–45% of the Rs variation. Sole maize was the highest carbon emitter, averaging 4233kgCha−1 per year, and sole pea the least emitter, averaging 1448kgCha−1 per year. Across the three years, the maize–wheat system had an average carbon emission (CE) of 2888kgCha−1, or 47% less compared to sole maize; the maize–pea system had CE of 2635kgCha−1, or 61% less compared to sole maize. Adoption of intercropping systems especially the inclusion of a legume like pea is an effective approach to increase crop productivity, reduce soil respiration, and lower carbon emission in arid lands.

Links between vegetation patterns, soil C and N pools and respiration rate under three different land uses in a dry Mediterranean ecosystem

Soil respiration (R s) is controlled by abiotic soil parameters interacting with characteristics of the vegetation and the soil microbial community. Few studies have attempted a comprehensive approach that simultaneously addresses the roles of all the major factors known to influence R s. Our goal was to explore the links between heterogeneity in R s, aboveground plant biomass and belowground properties in three representative land-use types in a dry Mediterranean ecosystem: (1) a 150-year-old mixed Aleppo pine-kermes oak open forest, (2) an abandoned agricultural field, which was cultivated with cereal for several years until abandonment in 1980, when establishment of typical Mediterranean shrubland vegetation started and (3) a rain-fed olive grove, which has been cultivated for 100 years. We selected two distinctive sampling periods coinciding with annual minimum or near minimum (December) and maximum (April) rates of R s in this dry Mediterranean ecosystem. In each sampling period, R s, temperature and moisture, aboveground plant biomass, carbon (C) and nitrogen (N) contents in both light and heavy soil organic matter fractions, extractable dissolved organic C (EDOC), as well as microbial and fine root biomass were measured within each land-use type. Across sites, R s rates were significantly higher in April (3.07 ± 0.1 μmol m−2 s−1) than in December (1.30 ± 0.1 μmol m−2 s−1). The labile soil organic matter fractions (light fraction C and N contents, microbial biomass C and EDOC) were consistently and strongly related to one another, and to a lesser extent, to the C and N contents in the heavy fraction across sites and seasons. Linear models adequately explained a large proportion of the within-site variability in R s (R 2 values ranged from 41 to 91 % depending on land use and season) but major controls on R s differed considerably between sites and seasons. Primary controls on spatial patterns in R s were linked to recent plant-derived C inputs in both forest and olive grove sites. However, in the abandoned agricultural field site R s appeared to be mainly driven by microbial activity, which could be sustained by intermediate or recalcitrant C and N pools derived from previous land use. Conversion of native woodland to agricultural land and subsequent land abandonment leads to profound changes in the relationships between R s, aboveground biomass and belowground properties in this dry Mediterranean ecosystem. While above- and belowground vegetation are the primary controls on spatial variability in labile soil C pools and R s in the open forest and olive grove sites, a complete lack of influence of current vegetation patterns on soil C pools and respiration rates in the abandoned agricultural field was observed.

Fire interacts with season to influence soil respiration in tropical savannas

Soil respiration (Rs) is the second-largest source of CO2 to the atmosphere in terrestrial systems. In tropical savannas seasonal moisture availability and frequent fires drive ecosystem dynamics and may have a considerable impact on soil carbon (C) cycling, including Rs. In order to test the effect of fire on soil C cycling we measured Rs in annually burnt and unburnt plots in wet and dry seasons at a long-term fire experiment established in savanna woodlands of northern Australia. There was a significant interaction between season and fire, with highest rates of daily Rs (722 mmol CO2 m−2 d−1) observed in the wet season on unburnt, leaf litter patches. The three fold higher Rs rate on unburnt plots in the wet season was due to greater root-derived respiration (Rroot: 356 mmol CO2 m−2 d−1), while smaller changes to soil-derived respiration (Rsoil: 51 mmol CO2 m−2 d−1) were simply the result of C moving through decomposition rather than combustion pathways. Relationships between instantaneous Rs and soil temperature showed hysteresis with variable direction, suggesting that season and fire treatment also influence the soil depth at which CO2 is produced. We suggest that (1) changes to fire regimes, through active management or climate change, in tropical savannas could have an impact on Rs, and (2) the direct effect of fire on soil C cycling is limited to the removal of aboveground litter inputs.

Effects of simulated acid rain on soil CO2 emission in a secondary forest in subtropical China

Acid rain, which is caused mainly by dissolution of sulfur dioxide (SO2) and nitrogen oxides (NOx) in the atmosphere, has been reported to have negative effects on ecosystems. However, few investigations have focused on the impacts of acid rain on soil CO2 emission in forest. In this study, the effects of simulated acid rain (SAR) on soil respiration (Rs) and its heterotrophic component (Rh) in a secondary forest in subtropical China were investigated. Soil CO2 efflux was measured by using a Li-8100 infrared gas analyzer with attached chamber. Measurements were generally made once a week from 21 March 2010 to 16 May 2011 in order to investigate the seasonal variations of Rs and Rh under different SAR treatments. Soil temperature and moisture at the depth of 5cm were measured at the time of soil CO2 efflux measurements. Results indicated that different SAR treatments exhibited similar seasonal patterns of Rs and Rh. Seasonal mean Rs rates for the CK (deionized water), A1 (pH 4.0), A2 (pH 3.0) and A3 (pH 2.0) treatments were 2.63, 1.92, 1.89 and 2.16μmolm−2s−1, respectively, while mean Rh rates for the four treatments were 1.80, 1.64, 1.76 and 1.79μmolm−2s−1, respectively. Two-factor analysis (respiration components and SAR) of variance implied that SAR had significant (p=0.031) effects on soil CO2 emissions, but this was contingent on the specific respiration components. SAR showed significant inhibition effects on Rs (autotrophic+heterotrophic components) rather than Rh. The ratio of Rh to Rs was significantly higher in the CK than in the acid rain treatments (A1, A2 and A3). Soil temperature and moisture were two controlling factors regulating the seasonal patterns of Rs and Rh for each of the SAR treatment. Soil temperature and moisture accounted for more than 80% of the seasonal variations observed in Rs and Rh. This work highlights that the effects of SAR are important to consider in assessing the annual soil CO2 emission, particularly under the scenario of increasing acid rain pollution.

Soil Respiration in Tibetan Alpine Grasslands: Belowground Biomass and Soil Moisture, but Not Soil Temperature, Best Explain the Large-Scale Patterns

The Tibetan Plateau is an essential area to study the potential feedback effects of soils to climate change due to the rapid rise in its air temperature in the past several decades and the large amounts of soil organic carbon (SOC) stocks, particularly in the permafrost. Yet it is one of the most under-investigated regions in soil respiration (Rs) studies. Here, Rs rates were measured at 42 sites in alpine grasslands (including alpine steppes and meadows) along a transect across the Tibetan Plateau during the peak growing season of 2006 and 2007 in order to test whether: (1) belowground biomass (BGB) is most closely related to spatial variation in Rs due to high root biomass density, and (2) soil temperature significantly influences spatial pattern of Rs owing to metabolic limitation from the low temperature in cold, high-altitude ecosystems. The average daily mean Rs of the alpine grasslands at peak growing season was 3.92 µmol CO2 m−2 s−1, ranging from 0.39 to 12.88 µmol CO2 m−2 s−1, with average daily mean Rs of 2.01 and 5.49 µmol CO2 m−2 s−1 for steppes and meadows, respectively. By regression tree analysis, BGB, aboveground biomass (AGB), SOC, soil moisture (SM), and vegetation type were selected out of 15 variables examined, as the factors influencing large-scale variation in Rs. With a structural equation modelling approach, we found only BGB and SM had direct effects on Rs, while other factors indirectly affecting Rs through BGB or SM. Most (80%) of the variation in Rs could be attributed to the difference in BGB among sites. BGB and SM together accounted for the majority (82%) of spatial patterns of Rs. Our results only support the first hypothesis, suggesting that models incorporating BGB and SM can improve Rs estimation at regional scale.

Analysis on lung cancer survival from 2001 to 2007 in Qidong, China

背景与目的生存率研究是反映癌症预后的一个重要指标。本研究旨在对启东2001年-2007年全人群肺癌登记病例进行生存率分析，为预后评价及防治提供依据。方法4, 451例登记病例的生存（死亡）情况随访截止于2009年12月31日；剔除只有死亡医学证明书（death certificate only, DCO）病例，实际纳入分析4, 382例。用SURV 3.01软件计算观察生存率（observed survival, OS）及相对生存率（relative survival, RS），并应用Hakulinen氏似然比检验法进行统计学检验。结果肺癌1年、3年、5年OS分别为23.73%、11.89%和10.01%，1年、3年、5年RS分别为24.86%、13.69%和12.73%。其中男性1年、3年、5年RS分别为23.70%、12.58%和11.73%，女性1年、3年、5年RS分别为27.89%、16.53%和15.21%，女性生存率高于男性，两组之间的差异具有统计学意义（χ2=13.77, P=0.032）。15岁-34岁、35岁-44岁、45岁-54岁、55岁-64岁、65岁-74岁及75+岁各年龄组的5年RS分别为35.46%、17.66%、11.97%、13.49%、10.61%和15.14%。启东2001年-2007年5年RS比1972年-2000年有了很大的提高。结论启东市全人群肺癌登记病例总体生存率有了较大的提高，但与国外发达国家相比尚有一定的差距，应当继续重视肺癌的诊治研究。

Temporal variation and climate dependence of soil respiration and its components along a 3000 m altitudinal tropical forest gradient

To simulate the effect of temperature on soil respiration rates, we translocated soil cores among four sites (3030, 1500, 1000, and 200 m asl) along an altitudinal tropical forest gradient in the Peruvian Andes, traversing a difference in mean annual temperature of 13.9°C. Rates of total (Rs) and heterotrophic (Rsh) respiration were measured twice a month from April 2007 to March 2009 and additionally for full 24 h periods. The diurnal range in Rs increased with altitude; this variation was mainly root and litter derived, whereas Rsh varied only slightly over full 24 h periods. Although mean annual daytime Rs rates were not significantly different among the four sites (4.45–4.05 μmol CO2 m−2 s−1), the annual amount of respired C decreased with increasing altitude from 1639 g C m−2 yr−1 at 200 m asl to 1064 g C m−2 yr−1 at 3030 m asl. The contribution of Rsh to Rs was not correlated with elevation and ranged from 25% to 60%. The temperature dependence of Rs was lower at the midelevation sites (Q10 of 2.07 and 2.94 at 1500 and 1000 m asl, respectively) than at the highest and lowest sites of the gradient (Q10 of 4.33 and 6.92 at 3030 and 200 m asl, respectively). The temperature sensitivity of Rsh was higher for the sites at 3030 and 200 m asl and increased with time, i.e., with the loss of the most labile C pools.

Seasonal variation in soil CO2 efflux in evergreen coniferous and broad‐leaved deciduous forests in a cool‐temperate forest, central Korea

AbstractWe measured the soil surface CO2 efflux (RS) from January 2005 to December 2006 in two neighboring stands in Gwangneung Forest, central Korea: evergreen coniferous forest (Abies holophylla, stand A) and broad‐leaved deciduous forest (Quercus‐dominated, stand Q). Regarding seasonal variation, RS rate was low during the winter and early spring months in each stand and peaked in late July [1170 (stand A) and 1130 (stand Q) in 2005, and 1000 (stand A) and 740 (stand Q) mg CO2 m−2 h−1 in 2006]. RS rate was higher in stand A than in stand Q during most of the growing season. The pattern of summer rainfall differed between 2005 and 2006. RS rate for both stands was suppressed significantly by the droughts in June 2005 and September 2006. After the heavy rainfall of July 2006, RS rate was lower than in July 2005 in both stands, but this decrement was much greater in stand Q than in stand A. In midsummer (August) 2006, under higher soil temperature (ST) and lower soil water content (SWC) conditions than in August 2005, RS rate of stand A was lower than that in August 2005, whereas stand Q showed no marked change. The exponential relationship between ST and RS accounted for approximately 91–97% of the RS variability in each stand and in each year. In stand A, the application of a second‐order polynomial function indicated a significant correlation between SWC and RS when the soil was warm (ST &gt; 15°C). Our results suggest that the seasonality of RS is strongly affected by the pattern of summer rainfall even in an Asia monsoon climate regime. In addition, the vegetation type (i.e., evergreen coniferous forest vs. broad‐leaved deciduous forest) plays a significant role in response of RS to various environmental fluctuations such as drought, heavy rainfall, and hot‐dry condition.

Soil respiration dynamics in Cinnamomum camphora forest and a nearby Liquidambar formosana forest in Subtropical China

Climate change can significantly affect carbon cycling of forest ecosystems. The diurnal and seasonal dynamics of soil respiration (R s) in Cinnamomum camphora and Liquidambar formosana forests were investigated by using infrared gas exchange analyzer of Li-Cor 6400-09 each month in 2006. Soil temperature and moisture were also measured. Diurnal variations in R s varied with daily soil temperature in the two forests. Across the growing season, soil respiration peaked on July 28 due to higher soil temperature and moisture conditions. Seasonal R s variations were predominantly influenced by soil temperature. Seasonal soil respirations in C. camphora and L. formosana forests were strongly related to soil temperature (x) at 5-cm depth (R s = 0.1598e0.1377x (R 2 = 0.9289, P = 0.001) and R s = 0.2177e0.0962x (R 2 = 0.927, P = 0.000)), while annual mean R s rate was 2.614 and 1.397 μmol m−2 s−1 and Q 10 values was 3.96 and 2.62 for the two forests, respectively. However, R s was not influenced by seasonal changes in soil moisture (w) in the two forests in 2006. We developed two equations (R s = −0.020w 2+0.497w+0.562 (R 2 = 0.109, P > 0.05), R s = −0.001w 2+0.072w+0.731(R 2 = 0.053, P > 0.05)) to describe the relationship between R s and soil moisture. A positive relationship between R s and soil moisture were observed when soil moisture was below 12.43% and 18.00%, but when soil moisture exceeded threshold values of 12.43% and 18.00%, soil moisture became the restraint factor for R s. Long-term observations of soil respiration and moisture are required to understand the temporal dynamics of soil respiration.

Comparison of global storm activity rate calculated from Schumann resonance background components to electric field intensity E0 Z

This work presents the results of a comparison between the global storm activity rate I RS and electric field intensity E 0 Z . The permanent analysis of the I RS may become an important tool for testing Global Electric Circuit models. I RS is determined by a new method that uses the background component of the first 7 Schumann resonances (SR). The rate calculations are based on ELF observations carried out in 2005 and 2006 in the observatory station “Hylaty” of the Jagiellonian University in the Eastern Carpathians (Kułak, A., Zięba, S., Micek, S., Nieckarz, Z., 2003. Solar variations in extremely low frequency propagation parameters: I. A two-dimensional telegraph equation (TDTE) model of ELF propagation and fundamental parameters of Schumann resonances, J. Geophys. Res., 108, 1270, doi:10.1029/2002JA009304). Diurnal runs of the I RS rate were compared with diurnal runs of E 0 Z amplitudes registered at the Earth's surface in the Geophysical Observatory of the Polish Academy of Sciences in Świder (Kubicki, M., 2005. Results of Atmospheric Electricity and Meteorological Observations, S. Kalinowski Geophysical Observatory at Świder 2004, Pub. Inst. Geophysics Polish Academy of Sciences, D-68 (383), Warszawa.). The days with the highest values of the correlation coefficient ( R) between amplitudes of both observed parameters characterizing atmosphere electric activity are shown. The seasonal changes of R, I RS and E 0 Z are also presented.

Determining Generation–Recombination Characteristics of a Semiconductor–Dielectric Interface from the Current Kinetics of Surface Minority Carrier Generation

Conditions for the one-to-one characterization of the generation (Gs) and surface recombination (Rs) rates of minority charge carriers (MCCs) in a metal–oxide–semiconductor (MOS) structure (in the case of strong nonequilibrium depletion) by the MCC surface generation current (I(t)) flowing in an external circuit of this structure are revealed. These conditions are the following: (1) the generation current I is independent of the time t (until the structure enters an equilibrium state) and the voltage Vg0 corresponding to the initial nonequilibrium depletion and (2) the duration of current steps I(Vg0) = const and, consequently, the equilibrium surface charge increase with increasing Vg0. The observed kinetics of the MCC generation current for the MCCs induced in an n-Si MOS structure at 293 K experimentally confirms the realization of these conditions. The values of the generation and recombination rates Gs = 2.84 × 1010 cm–2s–1 and Rs = 6.82 cm s–1 obtained from current levels I(Vg0) = const are typical of high-quality Si MOS structure. Additionally measured capacitance–voltage characteristics were used to determine the interface state density at the Si/SiO2 contact near the middle of the Si gap (Nss(E) ≅ 6.4 × 1010 cm–2eV–1), which allowed the estimation of the effective capture cross section of these states σ eff ≅ 1.4 × 10–16 cm2.

Carbon Dioxide Exchange of ‘Tifgreen’ Bermudagrass Exposed to Chilling Temperatures as Influenced by Iron and BA

Abstract ‘Tifgreen’ bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy] was exposed to 10°/7°C (day/night) temperatures following pretreatment with 120 mg Fe/m2 or 12.4 mg BA/m2 to determine their effects on net photosynthesis (Pn), respiration (Rs), leaf total nonstructural carbohydrate (TNC) content, and turf color at chilling temperatures. Average Pn and Rs rates were reduced 73% and 66%, respectively, by a 72-hr chilling period. Within 2 hr at 30° following chilling, Rs rates returned to prechill rates. However, Pn rates returned to within only 50% of prechill rates during the same recovery period. The lack of full photosynthetic recovery was associated with a 288% increase in leaf TNC. Iron increased Pn rates prior to chilling. This iron effect was associated with increased photosynthetic activity per unit of chlorophyll and was evident before, during, and after the chilling period. BA increased Pn rates before chilling and within 2 hr at 30° following chilling. However, during chilling, Pn rates for the BA treatment were similar to the control. Neither Fe nor BA significantly affected leaf TNC or Rs rates. Iron and BA caused higher turf color scores during chilling. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA).