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Field calibrations for a neutron probe and a capacitance sensor (Diviner 2000) for measuring the soil water content of a shrinking–swelling clay soil were substantially different from commonly used default values. Using our field calibrations, the two instruments estimated similar changes in the cumulative water content of a soil profile (0–1 m depth) over one growing season. 相似文献
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摘要:对皇帝蕉芽的消毒方法、外植体的诱导、幼芽的增殖培养、生根培养等进行了研究。结果表明:采用75%酒精60s--0.1%升汞12min(第一次8min 第二次4 min)的消毒方法,比较适宜于皇帝蕉外植体的消毒,易获得理想的无菌体系;在芽的诱导初期阶段,6-BA浓度采用5.0 mg/L,最适合皇帝蕉外植体的诱导;在幼芽的中高代增殖培养阶段,适宜采用MS 4.0mg/L6-BA 0.1mg/LNAA配方;在幼芽的高代增殖培养阶段,适宜采用MS 3.0mg/L6-BA 0.1mg/LNAA配方;在幼芽的生根阶段,适宜采用MS 2.5mg/LIBA 0.2mg/LNAA配方,幼苗生根快、根系壮实、发达,成活率高。 相似文献
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A field calibration experiment was carried out on salt‐affected clayey soil in Syria, to compare the sensitivity to soil electrical conductivity (ECe), and bulk density (ρb) of two instruments for estimating soil moisture: the neutron probe (NP) and the Diviner 2000 capacitance probe (CP). The results showed that the values of the correlation coefficient of the calibration were decreased when the ECe and ρb values increased; this decrease was more pronounced for the Diviner 2000, indicating that it was more sensitive to ρb and ECe than the NP. When only scaled frequency was used in the fitted equation, the Diviner 2000 in wet soil underestimated soil water content significantly at all depths, but especially in the top layer, by up to 0.09 cm3/cm3 compared with gravimetric determinations. However, in dry soil, the Diviner 2000 overestimated the volumetric water content by up to 0.05 cm3/cm3 in the top 15 cm, and by 0.03 cm3/cm3 at 30‐45 cm depth. The performance of the neutron probe was better overall; using a factory calibration curve no significant differences were observed between NP estimates and the gravimetric values. Including both ρb and ECe in the calibration equations improved the fits, although the regression coefficient (R2) for the Diviner 2000 remained low. 相似文献
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Kelsey A. Johnson James Sutherland-Smith Trisha J. Oura Amy F. Sato Bruce Barton 《Veterinary radiology & ultrasound》2023,64(1):86-94
Evaluation of brain disease in veterinary patients uses a wide variety of MRI sequences. A shortened protocol that maintains consistency of interpretation would reduce radiologist reporting time, patient anesthetic time, and client cost. The aims of this retrospective, methods comparison, observer agreement study were to evaluate whether abbreviated MRI protocols alter differential diagnoses and recommendations compared to our institution's standard protocol; evaluate interobserver agreement on standard brain MRIs; and assess whether differential diagnoses change after postcontrast images. Normal and pathologic canine and feline brain MRIs were retrieved from hospital archives. Three protocols were created from each: a 5-sequence noncontrast enhanced Fast Brain Protocol 1 (FBP1); a 6-sequence contrast-enhanced Fast Brain Protocol 2 (FBP2); and an 11-sequence standard brain protocol (SBP). Three blinded veterinary radiologists interpreted FBP images for 98 cases (1 reader/case) and SBP images for 20 cases (3 readers/case). A fourth observer compared these interpretations to the original MRI reports (OMR). Overall agreement between FBPs and OMR was good (k = 0.75) and comparable to interobserver agreement for multiple reviews of SBP cases. Postcontrast images substantially altered conclusions in 17/97 cases (17.5%), as well as improved interobserver agreement compared to noncontrast studies. The conclusions reached with shortened brain protocols were comparable to those of a full brain study. The findings supported the use of a 6-sequence brain MRI protocol (sagittal T2-weighted [T2w] TSE; transverse T2w turbo spin echo fluid-attenuated inversion recovery, T2*-weighted gradient recalled echo, T1-weighted spin echo, and diffusion weighted imaging/apparent diffusion coefficient; and postcontrast transverse T1-weighted spin echo) for dogs and cats with suspected intracranial disease. 相似文献
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脉冲星物理因脉冲星具有极高的密度、极强的磁场强度等极端物理环境而成为天体物理研究的热点.在两极辐射外间隙模型的基础上,对模型进行了如下考虑:①就对产生过程对脉冲星外间隙厚度因子的限制进行了深入分析;②考虑了脉冲星磁倾角对加速带电粒子运动的影响,计算了带电粒子投射角;③采用了新的计算伽玛射线辐射立体角的方法.在此基础上,将改进的模型运用到Fermi LAT新观测到的类Crab脉冲星(Crab-like Pul-sar):PSR J2229+6114,计算结果表明改进的外间隙模型能够较好的解释这颗脉冲星观测到的能谱和光变曲线. 相似文献
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C. Caprari C. Bergmann Q. Migheli G. Salvi P. Albersheim A. Darvill F. Cervone G. De Lorenzo 《Physiological and Molecular Plant Pathology》1993,43(6)
Extracellular endopolygalacturonase, purified from the pathogenic fungus Fusarium moniliforme, consists of four molecular forms (38, 41·5, 45, and 48·5 kDa, respectively. Three forms (38, 41·5, and 45 kDa) were purified to homogencity by FPLC on a Mono S column followed by electroelution after SDS-PAGE. The N-terminal amino acid sequences of each of the three forms, and of a mixture containing all four forms were shown to be identical to that predicted from the nucleotide sequence of the endopolygalacturonase gene previously cloned from F. moniliforme. Enzymatic deglycosylation experiments revealed the presence of N-linked, high mannose oligosaccharide side-chains on all four forms of endo polygalacturonase. Hydrogen fluoride catalysed chemical deglycosylation of the polygalacturonase mixture yielded a single polypeptide with an apparent molecular mass of 36·2 kDa. Southern blot analysis, carried out at high stringency with an endopolygalacturonase-specific probe on genomic DNA digested with three different restriction enzymes, showed a single hybridizing restriction fragment in all three digests. A single 2·0 Mb chromosome hybridized with the endo polygalacturonase-specific probe, as shown by Southern blot analysis of F. moniliforme chromosomes separated by CHEF electrophoresis. Northern blot analysis revealed only one mRNA species 1350 nt encoding endo polygalacturonase. These data indicate that a single gene encodes the endopolygalacturonases of F. moniliforme. 相似文献