University of Nebraska–Lincoln

About: University of Nebraska–Lincoln is a education organization based out in Lincoln, Nebraska, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 28059 authors who have published 61544 publications receiving 2139104 citations. The organization is also known as: Nebraska & UNL.

Validation of the CHIRPS satellite rainfall estimates over eastern Africa

Abstract: Long and temporally consistent rainfall time series are essential in climate analyses and applications. Rainfall data from station observations are inadequate over many parts of the world due to sparse or non-existent observation networks, or limited reporting of gauge observations. As a result, satellite rainfall estimates have been used as an alternative or as a supplement to station observations. However, many satellite-based rainfall products with long time series suffer from coarse spatial and temporal resolutions and inhomogeneities caused by variations in satellite inputs. There are some satellite rainfall products with reasonably consistent time series, but they are often limited to specific geographic areas. The Climate Hazards Group Infrared Precipitation (CHIRP) and CHIRP combined with station observations (CHIRPS) are recently produced satellite-based rainfall products with relatively high spatial and temporal resolutions and quasi-global coverage. In this study, CHIRP and CHIRPS were evaluated over East Africa at daily, dekadal (10-day) and monthly time scales. The evaluation was done by comparing the satellite products with rain gauge data from about 1200 stations. The CHIRP and CHIRPS products were also compared with two similar operation satellite rainfall products: the African Rainfall Climatology version 2 (ARC2) and the Tropical Applications of Meteorology using Satellite data (TAMSAT). The results show that both CHIRP and CHIRPS products are significantly better than ARC2 with higher skill and low or no bias. These products were also found to be slightly better than the latest version of the TAMSAT product at dekadal and monthly time scales, while TAMSAT performed better at daily time scale. The performance of the different satellite products exhibits high spatial variability with weak performances over coastal and mountainous regions.

Revision of taxonomic criteria for species demarcation in the family Geminiviridae, and an updated list of begomovirus species.

Abstract: Members of the family Geminiviridae characteristically have circular single-stranded DNAgenomes packaged within twinned (so-called geminate) particles. Geminiviruses are currentlydivided into four genera on the basis of their genome organizations and biological properties[2,20].Thosethathaveamonopartitegenomeandaretransmittedbyleafhoppervectors,primarilyto monocotyledonous plants, are included in the genus Mastrevirus, of which Maize streak virus isthe type species. Viruses that have monopartite genomes distinct from those of the mastrevirusesand that are transmitted by leafhopper vectors to dicotyledonous plants are included in thegenus Curtovirus, with Beet curly top virus as the type species. The genus Topocuvirus, recentlyrecognized by the International Committee on Taxonomy of Viruses (ICTV) [18], has only onemember (also the type species), Tomato pseudo-curly top virus, which has a monopartite genomeandistransmittedbyatreehoppervectortodicotyledonousplants.ThegenusBegomoviruscontainsviruses that are transmitted by the whitefly Bemisia tabaci (Gennadius) to dicotyledonous plants,with Bean golden yellow mosaic virus (originally Bean golden mosaic virus – Puerto Rico)asthetype species. Many begomoviruses have bipartite genomes (DNA A and DNA B components),although numerous begomoviruses with a monopartite genome occur in the Old World, and thereare some for which a single component is not infectious yet no DNA B component has been found.Geminiviruses cause significant yield losses to many crop plants throughout the world [5, 7].Because of their economic importance and the relative ease with which their DNA genomescan be cloned, many geminiviruses have been isolated and characterized. Guidelines for naming

Inhibition of growth and aflatoxin production by cinnamon and clove oils. cinnamic aldehyde and eugenol

Abstract: Previous work indicated that cinnamon was inhibitory to the growth of aflatoxin-producing molds. The objective of this study was to determine the specific components of cinnamon and cloves that may be effective against mold growth and toxin production. The effects of cinnamon oil, clove oil, cinnamic aldehyde and eugenol on growth and aflatoxin production by Aspergillus parasiticus were studied using yeast-extract sucrose broth as the substrate. All four substances inhibited mold growth and subsequent toxin production. Cinnamon and clove oils were inhibitory at 200–250 ppm, cinnamic aldehyde at 150 ppm and eugenol at 125 ppm. Since cinnamic aldehyde and eugenol are the respective major components of cinnamon and clove oils, it was concluded that these are the major active antifungal ingredients of these two essential oils. The inhibitory effect of these substances was judged to be inhibition of growth rather than of toxin production. When growth occurred after a delay, aflatoxin production occurred when the cultures reached secondary metabolism. Given sufficient time, cultures which were inhibited initially, but which subsequently grew, produced toxin levels equivalent to control cultures. Levels of the oils above 250 ppm and of cinnamic aldehyde and eugenol above 200 ppm completely inhibited mold growth, or permitted only a small amount of growth that never reached secondary metabolism and never produced aflatoxins during the time of this study.

Relationship between gross primary production and chlorophyll content in crops: Implications for the synoptic monitoring of vegetation productivity

Abstract: CO2/m 2 s in maize (GPP ranged from 0 to 3.1 mg CO2/m 2 s) and less than 0.2 mg CO2/m 2 s in soybean (GPP ranged from 0 to 1.8 mg CO2/m 2 s). Validation using an independent data set for irrigated and rainfed maize showed robustness of the technique; RMSE of GPP prediction was less than 0.27 mg CO2/m 2 s.