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排序方式: 共有136条查询结果,搜索用时 31 毫秒
71.
Guillén DA Palma M Natera R Romero R Barroso CG 《Journal of agricultural and food chemistry》2005,53(7):2412-2417
This paper describes a study of the possibility of obtaining regression models by means of partial least squares (PLS) and multiple linear regression (MLR) that would enable us to correlate a series of parameters, such as the concentration of short-chain organic acids, higher alcohols, and phenolic compounds with the age of vintage Sherry wines or "anadas". The aim of this study is to characterize how these parameters evolve with aging. If this could be done, it would then be possible to guarantee the age of such wines using objective variables. A PLS regression model was established that allows the age to be predicted with a mean deviation of 1.6 years with respect to the age of the wines. In the case of the MLR, a model with 6 variables was obtained that gives a mean deviation of 3.3 years in the predictions. 相似文献
72.
Mirta?G.?González Marta?E.?ContiEmail author R.?Martha?Palma Nilda?M.?Arrigo 《Biology and Fertility of Soils》2003,39(2):135-138
Humic fractions, arginine ammonification and soil respiration were monitored in spring, summer and autumn 1999 in natural pasture soil and in no-tillage or reduced-tillage soil under maize. The Typic Argiudoll soils, typical of the Argentine rolling pampa, can be structurally unstable, particularly when conventionally tilled, a form of soil management affecting the humification process. The no-tillage soil had a lower content of fulvic acids than the reduced-tillage soil in spring and summer, probably because the humification process was favored by residue management in no-tillage soil, with a significant increase in the most stable fraction. Both arginine ammonification and CO2 were significantly correlated with the humic acids and humin contents. No significant correlation was found with fulvic acids,probably due to the lability and high variability of this fraction. A high correlation was found between arginine ammonification and CO2. The highest index values were generally observed in natural pasture soil, whereas no-tillage soils showed a higher index value than reduced-tillage soils throughout, confirming the hypothesis that humification is more intense in the presence of organic residues. 相似文献
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75.
Ackermann M Ajello M Allafort A Baldini L Ballet J Barbiellini G Bastieri D Belfiore A Bellazzini R Berenji B Blandford RD Bloom ED Bonamente E Borgland AW Bottacini E Brigida M Bruel P Buehler R Buson S Caliandro GA Cameron RA Caraveo PA Casandjian JM Cecchi C Chekhtman A Cheung CC Chiang J Ciprini S Claus R Cohen-Tanugi J de Angelis A de Palma F Dermer CD do Couto E Silva E Drell PS Dumora D Favuzzi C Fegan SJ Focke WB Fortin P Fukazawa Y Fusco P Gargano F Germani S Giglietto N Giordano F 《Science (New York, N.Y.)》2011,334(6059):1103-1107
The origin of Galactic cosmic rays is a century-long puzzle. Indirect evidence points to their acceleration by supernova shockwaves, but we know little of their escape from the shock and their evolution through the turbulent medium surrounding massive stars. Gamma rays can probe their spreading through the ambient gas and radiation fields. The Fermi Large Area Telescope (LAT) has observed the star-forming region of Cygnus X. The 1- to 100-gigaelectronvolt images reveal a 50-parsec-wide cocoon of freshly accelerated cosmic rays that flood the cavities carved by the stellar winds and ionization fronts from young stellar clusters. It provides an example to study the youth of cosmic rays in a superbubble environment before they merge into the older Galactic population. 相似文献
76.
Piñeiro Z Cantos-Villar E Palma M Puertas B 《Journal of agricultural and food chemistry》2011,59(21):11683-11689
A validated HPLC method with fluorescence detection for the simultaneous quantification of hydroxytyrosol and tyrosol in red wines is described. Detection conditions for both compounds were optimized (excitation at 279 and 278 and emission at 631 and 598 nm for hydroxytyrosol and tyrosol, respectively). The validation of the analytical method was based on selectivity, linearity, robustness, detection and quantification limits, repeatability, and recovery. The detection and quantification limits in red wines were set at 0.023 and 0.076 mg L(-1) for hydroxytyrosol and at 0.007 and 0.024 mg L(-1) for tyrosol determination, respectively. Precision values, both within-day and between-day (n = 5), remained below 3% for both compounds. In addition, a fractional factorial experimental design was developed to analyze the influence of six different conditions on analysis. The final optimized HPLC-fluorescence method allowed the analysis of 30 nonpretreated Spanish red wines to evaluate their hydroxytyrosol and tyrosol contents. 相似文献
77.
Abdo AA Ackermann M Atwood WB Baldini L Ballet J Barbiellini G Baring MG Bastieri D Baughman BM Bechtol K Bellazzini R Berenji B Blandford RD Bloom ED Bogaert G Bonamente E Borgland AW Bregeon J Brez A Brigida M Bruel P Burnett TH Caliandro GA Cameron RA Caraveo PA Carlson P Casandjian JM Cecchi C Charles E Chekhtman A Cheung CC Chiang J Ciprini S Claus R Cohen-Tanugi J Cominsky LR Conrad J Cutini S Davis DS Dermer CD de Angelis A de Palma F Digel SW Dormody M do Couto E Silva E Drell PS 《Science (New York, N.Y.)》2008,322(5905):1218-1221
Energetic young pulsars and expanding blast waves [supernova remnants (SNRs)] are the most visible remains after massive stars, ending their lives, explode in core-collapse supernovae. The Fermi Gamma-Ray Space Telescope has unveiled a radio quiet pulsar located near the center of the compact synchrotron nebula inside the supernova remnant CTA 1. The pulsar, discovered through its gamma-ray pulsations, has a period of 316.86 milliseconds and a period derivative of 3.614 x 10(-13) seconds per second. Its characteristic age of 10(4) years is comparable to that estimated for the SNR. We speculate that most unidentified Galactic gamma-ray sources associated with star-forming regions and SNRs are such young pulsars. 相似文献
78.
Martí MC Camejo D Vallejo F Romojaro F Bacarizo S Palma JM Sevilla F Jiménez A 《Plant foods for human nutrition (Dordrecht, Netherlands)》2011,66(4):416-423
Pepper (Capsicum annuum L.) fruits are highly appreciated by producers and consumers for their economical and nutritional value. Four different cultivars
of coloured peppers in immature and mature stages were harvested throughout the spring and examined for their content of phenolic
compounds, ascorbic acid and total antioxidant capacity (TAA) as well as for lipid peroxidation and carbonyl proteins as index
of oxidative stress. Ripening and harvest period influenced the antioxidants and the development of oxidative processes in
the cultivars differently: lipid peroxidation increased in mature peppers except in one cultivar (Y1075), while no changes
in protein oxidation or in TAA were produced, except in Y1075 in which both parameters increased. Each cultivar presented
differences in antioxidant compounds depending on the harvest period, but we could recommend May as the optimal if all cultivars
have to be harvested at the same time, when levels of ascorbate, phenols and TAA were not decreased, fresh weight and proteins
were elevated, and levels of oxidation were not as high as in June (except for Y1075). A previous study of the response of
each cultivar to different environmental conditions results essential to establish a good program of selection of cultivars
with high quality and productivity. 相似文献
79.
Francesca Trinchella Maria Grazia Esposito Palma Simoniello Rosaria Scudiero 《Aquaculture Research》2013,44(7):1076-1084
The concentration of cadmium and lead ions was determined in digestive gland and mantle of mussels (Mytilus galloprovincialis) from five aquaculture stations located in the Gulf of Naples (Southern Italy, Tyrrhenian Sea). Metallothionein (MT) levels in the same tissues were also evaluated. This gulf represents a greatly urbanized area, characterized by an important commercial port and past industrial activities, terminated in the last decade of the 20th century. The results were compared with those obtained from mussels cultivated in a more pristine neighbouring area. Data demonstrate that the amount of both metals found in mussels harvested at the highly anthropogenic sites in the Gulf of Naples was comparable with that found in mussels from the more naturalistic site. The content of both cadmium and lead was not related with that of MT. Indeed, the amount of both metals in the digestive gland was greater than in the mantle, whereas the MT preferentially accumulated in the mantle. Possibly, the MT content in mantle was associated to the physiological function of the tissue, rather than heavy metals exposure. 相似文献
80.