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61.
D. C. Weindorf S. Chakraborty J. Herrero B. Li C. Castañeda A. Choudhury 《European Journal of Soil Science》2016,67(2):173-183
Arid soil is common worldwide and has unique properties that often limit agronomic productivity, specifically, salinity expressed as soluble salts and large amounts of calcium carbonate and gypsum. Currently, the most common methods for evaluating these properties in soil are laboratory‐based techniques such as titration, gasometry and electrical conductivity. In this research, we used two proximal sensors (portable X‐ray fluorescence (PXRF) and visible near‐infrared diffuse reflectance spectroscopy (Vis–NIR DRS)) to scan a diverse set (n = 116) of samples from arid soil in Spain. Then, samples were processed by standard laboratory procedures and the two datasets were compared with advanced statistical techniques. The latter included penalized spline regression (PSR), support vector regression (SVR) and random forest (RF) analysis, which were applied to Vis–NIR DRS data, PXRF data and PXRF and Vis–NIR DRS data, respectively. Independent validation (30% of the data) of the calibration equations showed that PSR + RF predicted gypsum with a ratio of performance to interquartile distance (RPIQ) of 5.90 and residual prediction deviation (RPD) of 4.60, electrical conductivity (1:5 soil : water) with RPIQ of 3.14 and RPD of 2.10, Ca content with RPIQ of 2.92 and RPD of 2.07 and calcium carbonate equivalent with RPIQ of 2.13 and RPD of 1.74. The combined PXRF and Vis–NIR DRS approach was superior to those that use data from a single proximal sensor, enabling the prediction of several properties from two simple, rapid, non‐destructive scans. 相似文献
62.
Self and cross-incompatibility determination by means of fruit and seed set experiments or pollen tube growth observations
in the style has been frequently reported to be unclear in pear (Pyrus communis L.). Thus,in order to develop a reliable in vivo method to test pollen-pistil incompatibility in pear, pollen tube performance has been studied along the pistil following
self and cross-pollinations. Results show that, while pollen tube growth in the style may be an unclear test, ovule observation
at the microscope for the presence of pollen tube in the nucellus is a proper method to test incompatibility in this crop.
With this analysis we could identify S-alleles of ‘Williams’ (S1S2) and ‘Coscia’(S3S4), and three of the four possible S-genotypes resulting from the ‘Williams’ × ‘Coscia’ cross, as represented by ‘Butirra Precoz
Morettini’ (S1S3), ‘Santa Maria Morettini’ (S2S3)and ‘Tosca’ (S1S4). This result demonstrates that ‘Williams’ and ‘Coscia’ cultivars do not share any allele in common. We also established
two new inter-incompatibility groups in pear. Furthermore, the presence of a common allele between ‘Williams’ and ‘Agua de
Aranjuez’,and ‘Coscia’ and ‘Agua de Aranjuez’, three apparently unrelated old cultivars, may indicate a narrower genetic base
than expected for European pear. This finding together with the fact that 40% of new released cultivars have direct or indirect
parental relationship with the cultivars ‘Coscia’ and/or ‘Williams’, anticipates the possibility of new cases of cross-incompatibility
for this crop in the future. Both the method described and the determination of the S-genotypes will facilitate the characterisation
of self and cross-incompatibility relationships in this species.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
63.
40Ar/39Ar dating of fine-grained alunite that formed during cave genesis provides ages of formation for the Big Room level of Carlsbad Cavern [4.0 to 3.9 million years ago (Ma)], the upper level of Lechuguilla Cave (6.0 to 5.7 Ma), and three other hypogene caves (11.3 to 6.0 Ma) in the Guadalupe Mountains of New Mexico. Alunite ages increase and are strongly correlative with cave elevations, which indicates an 1100-meter decline in the water table, apparently related to tectonic uplift and tilting, from 11.3 Ma to the present. 40Ar/39Ar dating studies of the hypogene caves have the potential to help resolve late Cenozoic climatic, speleologic, and tectonic questions. 相似文献
64.
Human injury inflicted by grizzly bears 总被引:1,自引:0,他引:1
S Herrero 《Science (New York, N.Y.)》1970,170(958):593-598
Grizzly bear (Ursus arctos horribilis) attacks resulting in human injury and known to have occurred in the national parks of North America were examined. Fifty-seven attacks in which 61 persons were injured took place in three national parks in the United States and accounted for 79 percent of the known injuries. The remaining 16 injuries occurred in four Canadian national parks. The 77 injured persons gives an injury rate of 1 person per 2 million visitors. 相似文献
65.
Gatti A Alvarez AR Araya D Mancini S Herrero E Santillan G Larrieu E 《Veterinary parasitology》2007,143(2):112-121
Immunodiagnosis in sheep presents problems of sensitivity and specificity, limiting its applicability in surveillance systems. The objective of this study was to develop a sensitive, specific and accessible technique for diagnosing cystic echinococcosis in naturally infected sheep and to evaluate the validity of necropsy as a reference test. A total of 247 sheep were studied at slaughterhouses, confirming the parasitological diagnosis with histology. Serum was processed with enzyme immunoassay (EIA) using three antigen preparations: total hydatid liquid (LHT), purified fraction of LHT (S2B) and purified lipoprotein (B). Western Blot (WB) was used as a control. EIA proved effective for differentiating Echinococcus granulosus from larval stage of Taenia hydatigena and intestinal cestodes in all three antigen preparations. Serums from macroscopically negative sheep were reactive to EIA and positive with WB. In the whole flock, sensitivity was 89.2% for LHT, 80.0% for S2B and 86.4% for B. Sensitivity in lambs was 78.6% for LHT, 75.0% for S2B and 64.3% for B. Macroscopic diagnosis at the time of slaughter was found to have limitations as a reference test for immunodiagnosis of cystic equinococcosis in sheep, so it was necessary to include histology and WB as reference tests. LHT was the antigen preparation of greatest value and EIA proved to be a sensitive and specific technique, adequate for surveillance systems and for evaluating control programmes. 相似文献
66.
Schnieder L Seekamp-Rahn K Borkowski J Wrede E Welge KH Aoiz FJ Bañiares L D'Mello MJ Herrero VJ Rábanos VS Wyatt RE 《Science (New York, N.Y.)》1995,269(5221):207-210
The H + H(2) exchange reaction constitutes an excellent benchmark with which to test dynamical theories against experiments. The H + D(2) (vibrational quantum number v = 0, rotational quantum number j = 0) reaction has been studied in crossed molecular beams at a collision energy of 1.28 electron volts, with the use of the technique of Rydberg atom time-of-flight spectroscopy. The experimental resolution achieved permits the determination of fully rovibrational state-resolved differential cross sections. The high-resolution data allow a detailed assessment of the applicability and quality of quasi-classical trajectory (QCT) and quantum mechanical (QM) calculations. The experimental results are in excellent agreement with the QM results and in slightly worse agreement with the QCT results. This theoretical reproduction of the experimental data was achieved without explicit consideration of geometric phase effects. 相似文献
67.
Measurements of ozone were carried out at two different sites in the area surrounding a thermal power plant located in the Northwest of Spain during 1993–1995. The concentration of O3 in the ambient air varied from 6 to 257 μg m-3 exhibiting a wide temporal, seasonal and spatial variation. On a few occasions 1-hr ozone concentration was more than 180 μg m-3, which represents the maximum 1-hr limit of ozone in ambient air as prescribed by the European Commission. 相似文献
68.
69.
70.
Scott E. Nielsen Stephen Herrero Richard D. Mace Micheal L. Gibeau 《Biological conservation》2004,120(1):101-113
We examined the spatial patterns of 297 human-caused grizzly bear mortalities from 1971 to 2002 within the Central Rockies ecosystem (CRE) of Canada to explore relationships between mortalities and variables reflecting human development, terrain, and vegetation. Using logistic regression, we modelled the distribution of grizzly bear mortalities based on local landscape attributes as well as examining variation among demographic status, seasons, and mortality type. Grizzly bear mortalities were concentrated in three main regions of the CRE: (1) Lake Louise; (2) Banff town site; and (3) Alberta Provincial lands near the Red Deer River. We found no evidence for environmental differences in mortality locations between sexes or seasons, while sub-adult male and legal harvest mortalities were more dispersed than other mortalities. Models describing the relative risk of mortality were positively associated with human access, water, and edge features, while negatively associated with terrain ruggedness and greenness indices. Model predictions fit well with independent data. Overall, relatively little of the landscape was secure from human-caused mortality for grizzly bears. This would be most directly remedied by controlling human access. 相似文献