100,836 research outputs found
Labour savings of Roundup Ready maize: Impact on cost and input substitution for South African smallholders
No full textThis study examines the impact of genetically modified maize on labour, cost and input substitutability for smallholders in South Africa. Producers of Roundup Ready® (RR) maize use significantly less child, female and male labour than non-RR producers, resulting in lower costs despite significantly higher herbicide, seed and fertiliser costs. A treatment effects model controlling for selection bias shows that the entire cost advantage and more can be attributed to the Roundup Ready® technology. These results are supported using a nonparametric kernel density estimator. Elasticities of factor substitution indicate strong substitutability among inputs; however, a lack of statistical significance limits the interpretation of the results.Citation: Regier, G. K., Dalton, T. J. (2014) Labour savings of Roundup Ready maize: Impact on cost and input substitution for South African smallholders. African Journal of Agricultural and Resource Economics, 9(3
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Handwritten biographical information on Paulina T. McClung Merritt
No full textA handwritten biography of Paulina T. McClung Merritt by an unknown author, 1892.
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
No full textIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Pelevin’s Trinity in the novel “t”: author – protagonist – reader
No full textThe article attempts to interpret Pelevin's artistic strategy in the novel "T" by exploring its subject organization and addressing the key problems of the author, the protagonist, and the reader as they are seen by the researcher. The article analyzes the peculiarities of constructing the narrative reality in the novel "T", and goes on to discuss Pelevin's philosophic models of the development of the humankind, and the emergence of his new anthropology
Measuring industry-science links through inventor-author relations: A profiling method
No full textIn this pilot study we examine the performance of text-based profiling in recovering a set of validated inventor-author links. In a first step we match patents and publications solely based on their similarity in content. Next, we compare inventor and author names on the highest ranked matches for the occurrence of name matches. Finally, we compare these candidate matches with the names listed in a validated set of inventor-author names. Our text-based profile methodology performs significantly better than a random matching of patents and publications, suggesting that text-based profiling is a valuable complementary tool to the name searches used in previous studies.innovation; industry-science links; text-based profiling;
Indirect evidence and the poverty of the stimulus: The case of anaphoric one
No full textIt is widely held that children’s linguistic input underdetermines the correct grammar, and that language learning must therefore be guided by innate linguistic constraints. Here, we show that a Bayesian model can learn a standard poverty-of-stimulus example, anaphoric one, from realistic input by relying on indirect evidence, without a linguistic constraint assumed to be necessary. Our demonstration does, however, assume other linguistic knowledge; thus, we reduce the problem of learning anaphoric one to that of learning this other knowledge. We discuss whether this other knowledge may itself be acquired without linguistic constraints.Stephani Foraker, Terry Regier, Naveen Khetarpal, Amy Perfors and Joshua Tenenbau
Time is of the Essence:Processing Temporal Connectives During Reading
No full textAn important study by Munte, Schiltz, and Kutas [Nature 395 (1998) 71-73] using ERPs (=Event-Related brain Potentials) suggested that sentences starting with the temporal connective before are more taxing for working memory than sentences starting with after, as evidenced by a slow negative shift for before sentences. According to Munte et al., before sentences present events out of the correct chronological order, as in Before the author submitted the paper [=second event], the journal changed its policy [=first event]. In order to come up with the correct discourse representation of the sentence, the correct chronological order has to be restored, leading to extra memory load. In the present experiments using a self-paced reading paradigm it will be shown that before sentences are not more difficult to process than after sentences, but that they are even read faster than after sentences. In addition, it is shown that before sentences in which events are presented in the correct chronological order, as in The journal changed its policy [=first event], before the author submitted the paper [=second event] are read more slowly than corresponding sentences with after. Implications for Munte et al.'s theory are discussed and objectives for future research are formulated.</p
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