962 research outputs found

    AN ANALYSIS OF THE ROLE OF FUTURES PRICES, CASH PRICES AND GOVERNMENT PROGRAMS IN ACREAGE RESPONSE

    Get PDF
    An integrated investigation of futures price, cash price, and government programs is presented in the context of an econometric model of acreage supply response for U.S. corn and soybeans. The analysis refines the role of different sources of price information in the farmers' acreage decision. It is found that the government corn support price program plays a major role in corn and soybean production decisions. Also, the results indicate that futures prices are not good proxies for expected future cash prices in the presence of government programs. This raises questions about the information efficiency of futures prices when government intervenes in the market place.Crop Production/Industries,

    Anisotropic higher derivative gravity and inflationary universe

    Get PDF
    Stability analysis of the Kantowski-Sachs type universe in pure higher derivative gravity theory is studied in details. The non-redundant generalized Friedmann equation of the system is derived by introducing a reduced one dimensional generalized KS type action. This method greatly reduces the labor in deriving field equations of any complicate models. Existence and stability of inflationary solution in the presence of higher derivative terms are also studied in details. Implications to the choice of physical theories are discussed in details in this paper.Comment: 9 page

    Draft genomes of two Artocarpus plants, jackfruit (A. heterophyllus) and breadfruit (A. altilis)

    Get PDF
    Two of the most economically important plants in the Artocarpus genus are jackfruit (A. heterophyllus Lam.) and breadfruit (A. altilis (Parkinson) Fosberg). Both species are long-lived trees that have been cultivated for thousands of years in their native regions. Today they are grown throughout tropical to subtropical areas as an important source of starch and other valuable nutrients. There are hundreds of breadfruit varieties that are native to Oceania, of which the most commonly distributed types are seedless triploids. Jackfruit is likely native to the Western Ghats of India and produces one of the largest tree-borne fruit structures (reaching up to 45 kg). To-date, there is limited genomic information for these two economically important species. Here, we generated 273 Gb and 227 Gb of raw data from jackfruit and breadfruit, respectively. The high-quality reads from jackfruit were assembled into 162,440 scaffolds totaling 982 Mb with 35,858 genes. Similarly, the breadfruit reads were assembled into 180,971 scaffolds totaling 833 Mb with 34,010 genes. A total of 2822 and 2034 expanded gene families were found in jackfruit and breadfruit, respectively, enriched in pathways including starch and sucrose metabolism, photosynthesis, and others. The copy number of several starch synthesis-related genes were found to be increased in jackfruit and breadfruit compared to closely-related species, and the tissue-specific expression might imply their sugar-rich and starch-rich characteristics. Overall, the publication of high-quality genomes for jackfruit and breadfruit provides information about their specific composition and the underlying genes involved in sugar and starch metabolism

    The Need for Laboratory Measurements and Ab Initio Studies to Aid Understanding of Exoplanetary Atmospheres

    Full text link
    We are now on a clear trajectory for improvements in exoplanet observations that will revolutionize our ability to characterize their atmospheric structure, composition, and circulation, from gas giants to rocky planets. However, exoplanet atmospheric models capable of interpreting the upcoming observations are often limited by insufficiencies in the laboratory and theoretical data that serve as critical inputs to atmospheric physical and chemical tools. Here we provide an up-to-date and condensed description of areas where laboratory and/or ab initio investigations could fill critical gaps in our ability to model exoplanet atmospheric opacities, clouds, and chemistry, building off a larger 2016 white paper, and endorsed by the NAS Exoplanet Science Strategy report. Now is the ideal time for progress in these areas, but this progress requires better access to, understanding of, and training in the production of spectroscopic data as well as a better insight into chemical reaction kinetics both thermal and radiation-induced at a broad range of temperatures. Given that most published efforts have emphasized relatively Earth-like conditions, we can expect significant and enlightening discoveries as emphasis moves to the exotic atmospheres of exoplanets.Comment: Submitted as an Astro2020 Science White Pape

    Encapsidation of APOBEC3G into HIV-1 virions involves lipid raft association and does not correlate with APOBEC3G oligomerization

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The cellular cytidine deaminase APOBEC3G (A3G), when incorporated into the human immunodeficiency virus type 1 (HIV-1), renders viral particles non-infectious. We previously observed that mutation of a single cysteine residue of A3G (C100S) inhibited A3G packaging. In addition, several recent studies showed that mutation of tryptophan 127 (W127) and tyrosine 124 (Y124) inhibited A3G encapsidation suggesting that the N-terminal CDA constitutes a viral packaging signal in A3G. It was also reported that W127 and Y124 affect A3G oligomerization.</p> <p>Results</p> <p>Here we studied the mechanistic basis of the packaging defect of A3G W127A and Y124A mutants. Interestingly, cell fractionation studies revealed a strong correlation between encapsidation, lipid raft association, and genomic RNA binding of A3G. Surprisingly, the presence of a C-terminal epitope tag affected lipid raft association and encapsidation of the A3G W127A mutant but had no effect on wt A3G encapsidation, lipid raft association, and interaction with viral genomic RNA. Mutation of Y124 abolished A3G encapsidation irrespective of the presence or absence of an epitope tag. Contrasting a recent report, our co-immunoprecipitation studies failed to reveal a correlation between A3G oligomerization and A3G encapsidation. In fact, our W127A and Y124A mutants both retained the ability to oligomerize.</p> <p>Conclusion</p> <p>Our results confirm that W127 and Y124 residues in A3G are important for encapsidation into HIV-1 virions and our data establish a novel correlation between genomic RNA binding, lipid raft association, and viral packaging of A3G. In contrast, we were unable to confirm a role of W127 and Y124 in A3G oligomerization and we thus failed to confirm a correlation between A3G oligomerization and virus encapsidation.</p
    corecore