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We compared lignocellulose (the second most abundant component of plant material) degradation over 8 months in contrasting
soils from each of five sites across the United States with the aim of assessing which soils are likely to store more C. The
soils were collected from a tallgrass prairie restoration (farmland, and plots restored in 1993 and 1979), the semiarid shrub-steppe
(cool, moist upper slope and warm, dry lower slope soils), long-term farmland (no-till and conventional-till), and from two
forest soils (loblolly pine and Douglas fir; fertilized and nonfertilized). Soils that rapidly metabolized freshly added C
exploited endogenous and newly transformed C to a lesser degree over the course of the incubation (lower slope shrub-steppe,
nonfertilized Douglas fir, and tallgrass prairie farmed and 1993 restorations). We also pooled the data to find a strong relationship
between sand content and lignocellulose C remaining in the soil after 8 months (R=0.68) and also between short-term storage of lignocellulose C (at 7 days) and lignocellulose C remaining after 8 months (R=0.94). To predict C storage, models of C and soil properties must be modified to reflect the structure and function of microbial
communities. Communities in richer soils may be more competent to use native C following fresh C additions when compared with
communities in poorer soils. 相似文献
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Introduction
The time from the onset of the P wave on electrocardiogram to the peak of late diastolic wave signal (PA-TDI interval) recorded by left atrial pulsed-wave tissue Doppler imaging (PW-TDI) is a surrogate of the total atrial conduction time, and it can predict the development of new-onset atrial fibrillation (AF) in people. This study investigated whether PA-TDI interval measured with PW-TDI at the level of lateral aspect of the mitral valve annulus could identify dogs which developed AF within 6 months after echocardiography.Animals
Forty-two dogs with different cardiac diseases were included; 21 dogs developed AF within 6 months after echocardiography (AF group) and 21 dogs did not (non-AF group). Each AF case was matched with a non-AF case for body weight and left atrium:aortic root ratio.Methods
This was a retrospective study. Review of signalment, underlying disease and echocardiography data were included. PA-TDI interval was measured offline from acquired PW-TDI images. PA-TDI interval and standard echocardiographic variables were compared between groups. Receiver operator characteristic curves were used to identify the best AF predictor. Univariate and multivariate regression were used to evaluate predictors of PA-TDI interval.Results
The AF group had significantly greater 2D left atrial maximal diameter, left-ventricular (LV) end-diastolic volume, M-Mode LV internal diameter and LV end-systolic volume index. PA-TDI was significantly longer in the AF group, and it was superior to other echocardiographic variables in predicting AF development within 6 months (AUC = 0.896).Conclusions
PA-TDI interval measured with PW-TDI at the lateral mitral valve annulus may identify dogs at risk of developing AF. 相似文献4.
陆地棉种子性状直接效应和母体效应的遗传分析 总被引：14，自引：6，他引：14
采用二倍体种子遗传模型及其分析方法，分析了陆地棉５个品种及其配制的Ｆ１、Ｆ２和正反回交一代（ＢＣ１、ＢＣ２、ＲＢＣ１和ＲＢＣ２）世代籽指、种仁率、容重和油分４个种子性状的直接效应、母体效应和细胞质效应。分析结果表明，４个棉子性状的遗传均以母体效应为主，种子直接遗传效应作用较小。各性状的直接效应与母体效应的协方差不显著。通过母体植株的遗传表现对这些性状选择更为有效。可以根据籽指小和容量大等性状母体植 相似文献
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