15,062 research outputs found

    National Newspaper Analysis of the Press Coverage of Jesse Jackson\u27s 1984 Presidential Campaign: The Confirmation of the Candidate

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    Jesse Jackson\u27s 1984 and 1988 presidential campaigns have motivated thousands of citizens throughout America to take a more active role in politics. The 1984 campaign witnessed many previously unregistered Americans actively participating in Jackson\u27s call to join the Rainbow Coalition. Four years later, Jackson once again hit a responsive chord within the American electorate, broadening his support base in his second run for the White House. His vibrant campaigns presented challenges not only to the American system of government, but also to accepted journalistic traditions in campaign reporting. Specifically, the dilemma has been a difficult one for journalists responsible for campaign coverage. How much coverage should a reporter give to Jesse Jackson\u27s campaign? Should he be treated like an Alan Cranston or Gary Hart in 1984, or a Paul Simon or Albert Gore in 1988? Or does the historical impact of his being the first black candidate to make a serious bid for the presidency warrant a different approach to press coverage? Highlighting this dilemma in the 1984 campaign, Dates and Gandy note: Jackson\u27s candidacy was a challenge for the press because on the one hand journalistic traditions would dictate that the ideological orientation of the media organization would constrain its coverage to be consistent with longstanding editorial practice.[1

    Structural Characterization of Zn(II)-, Co(II)-, and Mn(II)-loaded Forms of the argE-encoded \u3cem\u3eN\u3c/em\u3e-acetyl-L-ornithine Deacetylase from \u3cem\u3eEscherichia coli\u3c/em\u3e

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    The Zn, Co, and Mn K-edge extended X-ray absorption fine structure (EXAFS) spectra of the N-acetyl-l-ornithine deacetylase (ArgE) from Escherichia coli, loaded with one or two equivalents of divalent metal ions (i.e., [Zn(II)_(ArgE)], [Zn(II)Zn(II)(ArgE)], [Co(II)_(ArgE)], [Co(II)Co(II)(ArgE)], [Mn(II)_(ArgE)], and [Mn(II)Mn(II)(ArgE)]), were recorded. The Fourier transformed data (FT) for [Zn(II)_(ArgE)], [Zn(II)Zn(II)(ArgE)], [Co(II)_(ArgE)] and [Co(II)Co(II)(ArgE)] are dominated by a peak at 2.05 Å, that can be fit assuming five or six light atom (N,O) scatterers. Inclusion of multiple-scattering contributions from the outer-shell atoms of a histidine-imidazole ring resulted in reasonable Debye–Waller factors for these contributions and a slight reduction in the goodness-of-fit value (f′). Furthermore, the data best fit a model that included a M–M vector at 3.3 and 3.4 Å for Zn(II) and Co(II), respectively, suggesting the formation of a dinuclear site. Multiple scattering contributions from the outer-shell atoms of a histidine-imidazole rings are observed at ~ 3 and 4 Å for Zn(II)- and Co(II)-loaded ArgE suggesting at least one histidine ligand at each metal binding site. Likewise, EXAFS data for Mn(II)-loaded ArgE are dominated by a peak at 2.19 Å that was best fit assuming six light atom (N,O) scatterers. Due to poor signal to noise ratios for the Mn EXAFS spectra, no Mn–Mn vector could be modeled. Peak intensities for [M(II)_(ArgE)] vs. [M(II)M(II)(ArgE)] suggest the Zn(II), Co(II), and Mn(II) bind to ArgE in a cooperative manner. Since no structural data has been reported for any ArgE enzyme, the EXAFS data reported herein represent the first structural glimpse for ArgE enzymes. These data also provide a structural foundation for the future design of small molecules that function as inhibitors of ArgE and may potentially function as a new class of antibiotics

    False discovery rate regression: an application to neural synchrony detection in primary visual cortex

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    Many approaches for multiple testing begin with the assumption that all tests in a given study should be combined into a global false-discovery-rate analysis. But this may be inappropriate for many of today's large-scale screening problems, where auxiliary information about each test is often available, and where a combined analysis can lead to poorly calibrated error rates within different subsets of the experiment. To address this issue, we introduce an approach called false-discovery-rate regression that directly uses this auxiliary information to inform the outcome of each test. The method can be motivated by a two-groups model in which covariates are allowed to influence the local false discovery rate, or equivalently, the posterior probability that a given observation is a signal. This poses many subtle issues at the interface between inference and computation, and we investigate several variations of the overall approach. Simulation evidence suggests that: (1) when covariate effects are present, FDR regression improves power for a fixed false-discovery rate; and (2) when covariate effects are absent, the method is robust, in the sense that it does not lead to inflated error rates. We apply the method to neural recordings from primary visual cortex. The goal is to detect pairs of neurons that exhibit fine-time-scale interactions, in the sense that they fire together more often than expected due to chance. Our method detects roughly 50% more synchronous pairs versus a standard FDR-controlling analysis. The companion R package FDRreg implements all methods described in the paper

    Synthesis and Activity of Six-Membered Cyclic Alkyl Amino Carbene–Ruthenium Olefin Metathesis Catalysts

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    Ru–cyclic alkyl amino carbene (Ru–CAAC) olefin metathesis catalysts perform extraordinarily in metathesis macrocyclization and ethenolysis, but previous studies have been limited to the use of five-membered CAAC (CAAC-5) ligands. In this work, we synthesized a different group of ruthenium catalysts with more σ-donating and π-accepting six-membered CAAC (CAAC-6) ligands, and their metathesis activity was probed through initiation studies, ring-closing metathesis (RCM), cross-metathesis, and ethenolysis. These catalysts display higher initiation rates than analogous Ru–CAAC-5 complexes but demonstrate lower activity in RCM and ethenolysis

    Identifying Market Preferences for High Selenium Beef

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    Selenium is an element found in relatively high concentrations in crops and livestock raised on high-selenium soils located in North and South Dakota. Evidence suggests that a high-selenium diet such as would be obtained from consuming these products can reduce the risk of certain cancers. The region's livestock and grain producers are exploring potential high-selenium product marketing opportunities. A choice experiment was conducted to identify preferred attributes for a high-selenium beef product and the characteristics of potential market segments. In a national survey, participants chose between different levels of health claim approval and research, prices, and selenium origin. A multinomial logit regression model was estimated. Labeling reflecting scientific support linking selenium and reduced cancer risk, and natural-source selenium was ineffective. Marketing opportunities identified are consistent with existing functional food market segments and include consumers with higher income and education, 45 to 55 years of age, and with children.Choice Experiment, FDA approval, Functional Foods, Health Claim, Labeling, Selenium, Consumer/Household Economics, Livestock Production/Industries,
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