971 resultados para cereal grains
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Thank you for inviting me to speak with you today. It is a pleasure to be here. I look forward to working with you in the days ahead; in fact, I look forward “to attending” this conference in the future and knowing many of you by name.
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In Arkansas, blackbirds are responsible for appreciable damage to rice, grain sorghum, oats, wheat, rye, and corn. By far, the greatest damage is to rice. As is shown in the following table, the losses to rice producers amounted to an estimated $3,049,055 in 1968, the last year that a survey was made. Nearly two-thirds (63%) of this loss was to standing rice destroyed and to the cost of bird control measure in standing rice. The remaining losses ($2,140,320 ) are to seeding or to efforts to control bird depredations to new seeding, (see Table 1). Blackbird damage to grain sorghum and corn was mostly to standing grain; that to oats, wheat and rye, to seeding, although there is occasional damage to standing grain. Additional problems are caused by blackbirds in feed lots. The total losses to Arkansas agricultural producers due to blackbirds in 1968 was about $3,500,000. Bird damage in a specific locality and on specific crops seems to vary in intensity from year to year. However, surveys during the past ten years suggest a fairly consistent level of total damage state-wide. The damage in 1968-and I believe in 1969—was somewhat lighter than we have come to expect from past exper¬ience. (See table 2.) On a per acre basis the damage in 1968 showed a considerable decline when compared to previous years. A part of this decline is probably a temporary situation. Some of the decline in losses to rice and grain sorghum, however, are due to changes in varieties, such as development of bird-resistant milo, and to changes in cultural methods. Further appreciable reductions due to changes in these factors seem unlikely, (see table 3.) Since rice producers sustain the greatest losses to birds, they have generated the greatest demand for bird control programs. Three species are responsible for most of the damage to rice. They are the red-winged blackbird, common grackle and brown-headed cowbird. These birds have created problems for rice producers since the first successful rice crop was grown near Lonoke, Arkansas, in 1904.
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Lia Goncalves, Claudia Ines da Silva, and Maria Luisa Tunes Buschini (2012) Collection of pollen grains by Centris (Hemisiella) tarsata Smith (Apidae: Centridini): Is C. tarsata an oligolectic or polylectic species? Zoological Studies 51(2): 195-203. Among pollinator species, bees play a prominent role in maintaining biodiversity because they are responsible, on average, for 80% of angiosperm pollination in tropical regions. The species richness of the bee genus Centris is high in South America. In Brazil, these bees occur in many types of ecosystems. Centris tarsata is an endemic species occurring only in Brazil. No previous studies considered interactions between plants and this bee species in southern Brazil, where it is the most abundant trap-nesting bee. Accordingly, the goals of this study were to investigate plants used by this species for its larval food supply and determine if this bee is polylectic or oligolectic in this region. This work was conducted in the Parque Municipal das Araucarias, Guarapuava (PR), southern Brazil, from Mar. 2002 to Dec. 2003. Samples of pollen were collected from nests of these bees and from flowering plants in grassland and swamp areas where the nests were built. All of the samples were treated with acetolysis to obtain permanent slides. The family Solanaceae was visited most often (71%). Solanum americanum Mill. (28.6%) and Sol. variabile Mart. (42.4%) were the primary pollen sources for C. tarsata in the study area. We found that although C. tarsata visited 20 species of plants, it preferred Solanum species with poricidal anthers and pollen grains with high protein levels. This selective behavior by females of C. tarsata indicates that these bees are oligolectic in their larval provisioning in this region of southern Brazil. http://zoolstud.sinica.edu.tw/Journals/51.2/195.pdf
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Aflatoxins can cause great economic losses and serious risks to humans and animals health. The largest aflatoxin producers belong to Aspergillus section Flavi and can occur naturally in food commodities. Studies showed that molecular tools as well as the type of sclerotia produced by the strains could be helpful for identification of Aspergillus species and could be correlated with levels of toxin production. The purpose of this work was to characterize the genetic diversity using AFLP technique, the type of sclerotia and the ability of aflatoxin production by isolated strains from corn of different origins in Brazil, and to verify whether qPCR based on aflR and aflP genes is appropriate for estimating the level of aflatoxin production. All the 75 strains were classified as A. flavus and the AFLP technique showed a wide intraspecific variability within them. Regarding sclerotia production, 34% were classified as S and 66% as L type. Among the aflatoxin-producers, 52.8% produced aflatoxin B-1, while 47.2% aflatoxins B-1 and B-2. Statistical analysis showed no correlation between sclerotia production and aflatoxigenicty, and no correlation between the phylogenetic clusters and aflatoxin production. Concerning the relative expression of aflR and aflP, Pearson's correlation test demonstrated low positive correlation between the expression of the aflR and aflP genes and the production of AFB(1) and AFB(2), but showed high positive correlation between aflR and aflP expression. In contrast to the other reference strains, A. oryzae ATCC 7282 showed no amplification of aflR and aflP. The results highlight the need for detection of reliable and reproducible markers with a high positive correlation with aflatoxin production.
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(Viability, production and morphology of pollen grains for different species in the genus Manihot (Euphorbiaceae)). The objective of this work was to characterize the viability, production and morphology of pollen for different species in the genus Manihot. Floral buds from Manihot accessions were collected from two germplasm banks at Embrapa Cassava & Fruits. The viability of the pollen was assessed via colorimetric, in vitro and in vivo assays. The diameter of the pollen grains was determined by measuring the transversal length of the grain. The experimental design was entirely randomized. Studies on pollen ultrastructure were performed via scanning electron microscopy. Pollen viability was high in the colorimetric tests and intermediate in vivo tests; there was no germination in the in vitro tests. The average production for all accessions was 1,253 pollen grains per floral bud. The size of the pollen grains varied from 132 to 163 pm in the wild accessions, and 129 to 146 pm in the cultivated accessions. The pollen grains for all accessions were very large, apolar, spherical as well as inaperturate, with an exine ornamented with pila organized in a Croton pattern. The wild accessions, in general, produced more and larger pollen grains compared with the cultivated accessions.
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We report the first tungsten isotopic measurements in stardust silicon carbide (SiC) grains recovered from the Murchison carbonaceous chondrite. The isotopes (182,183,184,186)Wand (179,180)Hf were measured on both an aggregate (KJB fraction) and single stardust SiC grains (LS+ LU fraction) believed to have condensed in the outflows of low-mass carbon-rich asymptotic giant branch (AGB) stars with close-to-solar metallicity. The SiC aggregate shows small deviations from terrestrial (= solar) composition in the (182)W/(184)Wand (183)W/(184)Wratios, with deficits in (182)W and (183)W with respect to (184)W. The (186)W/(184)W ratio, however, shows no apparent deviation from the solar value. Tungsten isotopic measurements in single mainstream stardust SiC grains revealed lower than solar (182)W/(184)W, (183)W/(184)W, and (186)W/(184)W ratios. We have compared the SiC data with theoretical predictions of the evolution of W isotopic ratios in the envelopes of AGB stars. These ratios are affected by the slow neutron-capture process and match the SiC data regarding their (182)W/(184)W, (183)W/(184)W, and (179)Hf/(180)Hf isotopic compositions, although a small adjustment in the s-process production of (183)W is needed in order to have a better agreement between the SiC data and model predictions. The models cannot explain the (186)W/(184)W ratios observed in the SiC grains, even when the current (185)W neutron-capture cross section is increased by a factor of two. Further study is required to better assess how model uncertainties (e. g., the formation of the (13)C neutron source, the mass-loss law, the modeling of the third dredge-up, and the efficiency of the (22)Ne neutron source) may affect current s-process predictions.
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[ES] Todavía hoy, los cereales son en gran medida el alimento más importante de la humanidad. En las Islas Canarias existe un alimento muy típico elaborado a base de cereales tostados y molidos conocido como gofio, que ya era consumido por los primeros habitantes de las islas. Se considera como un alimento seguro por su baja humedad y por alcanzar temperaturas de 130ºC durante su elaboración. Sin embargo, puede contener sustancias tóxicas conocidas como micotoxinas y, por otro lado, es posible que se elabore gofio con productos transgénicos sin declararse en la etiqueta. Debido a la actual exigencia de los consumidores de productos de calidad, se consideró de interés hacer un estudio sobre la presencia de aflatoxinas (una clase de micotoxinas) y de transgénicos en el gofio comercializado en la isla de Gran Canaria.
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Researches performed during the PhD course intended to assess innovative applications of near-infrared spectroscopy in reflectance (NIR) in the production chain of beer. The purpose is to measure by NIR the "malting quality" (MQ) parameter of barley, to monitor the malting process and to know if a certain type of barley is suitable for the production of beer and spirits. Moreover, NIR will be applied to monitor the brewing process. First of all, it was possible to check the quality of the raw materials like barley, maize and barley malt using a rapid, non-destructive and reliable method, with a low error of prediction. The more interesting result obtained at this level was that the repeatability of the NIR calibration models developed was comparable with the one of the reference method. Moreover, about malt, new kinds of validation were used in order to estimate the real predictive power of the proposed calibration models and to understand the long-term effects. Furthermore, the precision of all the calibration models developed for malt evaluation was estimated and statistically compared with the reference methods, with good results. Then, new calibration models were developed for monitoring the malting process, measuring the moisture content and other malt quality parameters during germination. Moreover it was possible to obtain by NIR an estimate of the "malting quality" (MQ) of barley and to predict whether if its germination will be rapid and uniform and if a certain type of barley is suitable for the production of beer and spirits. Finally, the NIR technique was applied to monitor the brewing process, using correlations between NIR spectra of beer and analytical parameters, and to assess beer quality. These innovative results are potentially very useful for the actors involved in the beer production chain, especially the calibration models suitable for the control of the malting process and for the assessment of the “malting quality” of barley, which need to be deepened in future studies.
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Fusarium Head Blight (FHB) is a worldwide cereal disease responsible of significant yield reduction, inferior grain quality, and mycotoxin accumulation. Fusarium graminearum and F. culmorum are the prevalent causal agents. FHB has been endemic in Italy since 1995, while there are no records about its presence in Syria. Forty-eight and forty-six wheat kernel samples were collected from different localities and analyzed for fungal presence and mycotoxin contamination. Fusarium strains were identified morphologically but the molecular confirmation was performed only for some species. Further differentiation of the chemotypes for trichothecene synthesis by F. graminearum and F. culmorum strains was conducted by PCR assays. Fusarium spp. were present in 62.5% of Syrian samples. 3Acetyl-Deoxynivalenol and nivalenol chemotypes were found in F. culmorum whilst all F. graminearum strains belonged to NIV chemotype. Italian samples were infected with Fusarium spp for 67.4%. 15Ac-DON was the prevalent chemotype in F. graminearum, while 3Ac-DON chemotype was detected in F. culmorum. The 60 Syrian Fusarium strains tested for mycotoxin production by HPLC-MS/MS have shown the prevalence of zearalenone while the emerging mycotoxins were almost absent. The analysis of the different Syrian and Italian samples of wheat kernels for their mycotoxin content showed that Syrian kernels were mainly contaminated with storage mycotoxins, aflatoxins and ochratoxin whilst Italian grains with mainly Fusarium mycotoxins. The aggressiveness of several Syrian F. culmorum isolates was estimated using three different assays: floret inoculation in growth chamber, ear inoculation in the field and a validated new Petri-dish test. The study of the behaviour of different Syrian wheat cultivars, grown under different conditions, has revealed that Jory is a FHB Syrian tolerant cultivar. This is the first study in Syria on Fusarium spp. associated to FHB, Fusarium mycotoxin producers and grain quality.
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We study how species richness of arthropods relates to theories concerning net primary productivity, ambient energy, water-energy dynamics and spatial environmental heterogeneity. We use two datasets of arthropod richness with similar spatial extents (Scandinavia to Mediterranean), but contrasting spatial grain (local habitat and country). Samples of ground-dwelling spiders, beetles, bugs and ants were collected from 32 paired habitats at 16 locations across Europe. Species richness of these taxonomic groups was also determined for 25 European countries based on the Fauna Europaea database. We tested effects of net primary productivity (NPP), annual mean temperature (T), annual rainfall (R) and potential evapotranspiration of the coldest month (PETmin) on species richness and turnover. Spatial environmental heterogeneity within countries was considered by including the ranges of NPP, T, R and PETmin. At the local habitat grain, relationships between species richness and environmental variables differed strongly between taxa and trophic groups. However, species turnover across locations was strongly correlated with differences in T. At the country grain, species richness was significantly correlated with environmental variables from all four theories. In particular, species richness within countries increased strongly with spatial heterogeneity in T. The importance of spatial heterogeneity in T for both species turnover across locations and for species richness within countries suggests that the temperature niche is an important determinant of arthropod diversity. We suggest that, unless climatic heterogeneity is constant across sampling units, coarse-grained studies should always account for environmental heterogeneity as a predictor of arthropod species richness, just as studies with variable area of sampling units routinely consider area.