نتایج جستجو برای: gc and gcms

تعداد نتایج: 16832498  

2013
Nicola Scafetta

Global surface temperature records (e.g. HadCRUT4) since 1850 are characterized by climatic oscillations synchronous with specific solar, planetary and lunar harmonics superimposed on a background warming modulation. The latter is related to a long millennial solar oscillation and to changes in the chemical composition of the atmosphere (e.g. aerosol and greenhouse gases). However, current gene...

2013
Farzin Shabani Lalit Kumar

Global climate model outputs involve uncertainties in prediction, which could be reduced by identifying agreements between the output results of different models, covering all assumptions included in each. Fusarium oxysporum f.sp. is an invasive pathogen that poses risk to date palm cultivation, among other crops. Therefore, in this study, the future distribution of invasive Fusarium oxysporum ...

2008
A. R. STINE N. Y. KRAKAUER

during the 1970s made possible the observation of the seasonally shifting patterns of global precipitation. It was not until recently, however, that the record could be considered long enough to investigate longer-term trends and the relationship between global precipitation and global warming. Using data from the Special Sensor Microwave Imager (SSM/I) instrument, Wentz et al. [2007] reported ...

2016
Jyoti Goutam R N Kharwar Vinod Kumar Tiwari Amrita Mishra Shweta Singh

Present work is directed toward the isolation and identification of biological active (antimicrobial) compound from metabolite extracted from endophytic fungus Emericella qaudrilineata(RS-5) (Accession number KC662361). Crude extracted from endophytic fungus Emericella qaudrilineata possessing antibacterial activity was subjected to bioassay guided fractionation in which toluene fraction exhibi...

2008
Qiong Yang Qiang Fu John Austin Andrew Gettelman Feng Li Holger Vömel

[1] We quantify the vertical velocity and upward mass flux in the tropical lower stratosphere on the basis of accurate radiative heating rate calculations using 8-year Southern Hemisphere Additional Ozonesondes balloon-borne measurements of temperature and ozone and cryogenic frost-point hygrometer measured water vapor in the tropics (15 S—10 N). The impact of tropospheric clouds on the stratos...

2011
Olubunmi Atolani Stephen O. Adeyemi Essiet Akpan Charles B. Adeosun Gabriel A. Olatunji

The chemical composition of Kigelia pinnata root oil extracted with n-hexane was analyzed by GC/GCMS. The antioxidant potential of the oil was compared to that of ethyl acetate and methanol extracts of the root. UV and IR spectroscopic techniques were used to carry out partial characterization of the oil and extracts. The free radical scavenging activity by spectrophotometric assay on the reduc...

Journal: :Phytochemical analysis : PCA 2009
Mary Lucero Rick Estell María Tellez Ed Fredrickson

INTRODUCTION Plant volatiles (PVOCs) are important targets for studies in natural products, chemotaxonomy and biochemical ecology. The complexity of PVOC profiles often limits research to studies targeting only easily identified compounds. With the availability of mass spectral libraries and recent growth of retention index (RI) libraries, PVOC identification can be achieved using only gas chro...

2012
Elizabeth A. Barnes Dennis L. Hartmann

[1] A Rossby wave breaking identification method is presented which searches for overturning of absolute vorticity contours on pressure surfaces. The results are compared to those from an analysis of isentropic potential vorticity, and it is demonstrated that both yield similar wave breaking distributions. As absolute vorticity is easily obtained from most model output, we present wave breaking...

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