1,643 research outputs found

    CONTINGENT VALUATION FOCUS GROUPS: INSIGHTS FROM ETHNOGRAPHIC INTERVIEW TECHNIQUES

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    Despite the many important uses (and potential abuses) of focus groups in survey design, the CV literature presents few guidelines to aid moderators in their interaction with focus group participants. This paper draws on the theory and practice of ethnographic interviewing to introduce general guidelines that can improve focus groups as an aid to CV research. The proposed guidelines illustrate types of questions that should reduce speculation and moderator-introduced bias in focus group responses, and improve the correspondence between focus group responses and actual behavior. The paper illustrates these ethnographic guidelines through a CV application concerning watershed resources.Research Methods/ Statistical Methods,

    Dipole Moment of Ammonia‐Borane

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    The dipole moment of ammonia‐borane, H3NBH3, has been measured as 4.9 debye units in dioxane solution; the results are discussed briefly.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71099/2/JCPSA6-29-1-1-1.pd

    Dipole Moment of Tetraborane

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    The dipole moment of tetraborane, as measured in benzene solution by a heterodyne beat method, is 0.56±0.1.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70423/2/JCPSA6-30-4-1075-1.pd

    SOME RESPONSES OF THE BEAN PLANT TO CHLORATE AND PERCHLORATE IONS

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    A search for ortho-benzyne (o-C6H4) in CRL 618

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    Polycyclic aromatic hydrocarbons (PAHs) have been proposed as potential carriers of the unidentified infrared bands (UIRs) and the diffuse interstellar bands (DIBs). PAHs are not likely to form by gas-phase or solid-state interstellar chemistry, but rather might be produced in the outflows of carbon-rich evolved stars. PAHs could form from acetylene addition to the phenyl radical (C6H5), which is closely chemically related to benzene (C6H6) and ortho-benzyne (o-C6H4). To date, circumstellar chemical models have been limited to only a partial treatment of benzene-related chemistry, and so the expected abundances of these species are unclear. A detection of benzene has been reported in the envelope of the proto-planetary nebula (PPN) CRL 618, but no other benzene-related species has been detected in this or any other source. The spectrum of o-C6H4 is significantly simpler and stronger than that of C6H5, and so we conducted deep Ku-, K- and Q-band searches for o-C6H4 with the Green Bank Telescope. No transitions were detected, but an upper limit on the column density of 8.4x10^13 cm^-2 has been determined. This limit can be used to constrain chemical models of PPNe, and this study illustrates the need for complete revision of these models to include the full set of benzene-related chemistry.Comment: 13 pages, 4 figures, to be published in The Astrophysical Journal Letter

    A Survey of Ligand Effects Upon the Reaction Entropies of Some Transition Metal Redox Couples

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    The reaction entropies ∆S°_rc of a number of transition metal redox couples of the form M(III)/(II) in aqueous solution have been determined using nonisothermal electrochemical cells in order to explore the effect of varying the ligand structure upon the nature of the ion-solvent interactions. Examinations of six aquo couples of the form M(OH_2)_n&3+/2+ with varying metal M yielded ∆S°_rc values in the range 36-49 eu. In order to scrutinize the effect of replacing aquo with ammine and simple anionic ligands, Ru(III)/(II) couples were employed since the relative substituion inertness of both oxidation states allowed ∆S°_rc to be determined using cyclic voltammetry. The stepwise replacement of aquo by ammine ligands results in substantial reductions in ∆S°_rc which are attributed to the smaller extent of ligand-solvent hydrogen bonding for ammine compared with aquo ligands. Substitution of both aquo and ammine by anionic ligands also results in substantial reductions in ∆S°_rc. A number of M(III)/(II) couples containing chelating ligands were also examined. Sizable differences in ∆S°_rc were found between Co(III)/(II) couples and the corresponding Ru(III)/(II) and Fe(III)/(II) couples. Suggested explanations are differences in ligand conformation and electron delocalization effects. The possible contribution of outer-sphere solvent structuring effects to the large reorganization energies observed for electron exchange of aquo complexes is noted. The validity of the assumptions required for the estimation of ∆S°_rc from nonisothermal cell measurements is discussed

    A genomic analysis and transcriptomic atlas of gene expression in Psoroptes ovis reveals feeding- and stage-specific patterns of allergen expression

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    Background: Psoroptic mange, caused by infestation with the ectoparasitic mite, Psoroptes ovis, is highly contagious, resulting in intense pruritus and represents a major welfare and economic concern for the livestock industry Worldwide. Control relies on injectable endectocides and organophosphate dips, but concerns over residues, environmental contamination, and the development of resistance threaten the sustainability of this approach, highlighting interest in alternative control methods. However, development of vaccines and identification of chemotherapeutic targets is hampered by the lack of P. ovis transcriptomic and genomic resources. Results: Building on the recent publication of the P. ovis draft genome, here we present a genomic analysis and transcriptomic atlas of gene expression in P. ovis revealing feeding- and stage-specific patterns of gene expression, including novel multigene families and allergens. Network-based clustering revealed 14 gene clusters demonstrating either single- or multi-stage specific gene expression patterns, with 3075 female-specific, 890 male-specific and 112, 217 and 526 transcripts showing larval, protonymph and tritonymph specific-expression, respectively. Detailed analysis of P. ovis allergens revealed stage-specific patterns of allergen gene expression, many of which were also enriched in "fed" mites and tritonymphs, highlighting an important feeding-related allergenicity in this developmental stage. Pair-wise analysis of differential expression between life-cycle stages identified patterns of sex-biased gene expression and also identified novel P. ovis multigene families including known allergens and novel genes with high levels of stage-specific expression. Conclusions: The genomic and transcriptomic atlas described here represents a unique resource for the acarid-research community, whilst the OrcAE platform makes this freely available, facilitating further community-led curation of the draft P. ovis genome

    A reduced-order strategy for 4D-Var data assimilation

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    This paper presents a reduced-order approach for four-dimensional variational data assimilation, based on a prior EO F analysis of a model trajectory. This method implies two main advantages: a natural model-based definition of a mul tivariate background error covariance matrix Br\textbf{B}_r, and an important decrease of the computational burden o f the method, due to the drastic reduction of the dimension of the control space. % An illustration of the feasibility and the effectiveness of this method is given in the academic framework of twin experiments for a model of the equatorial Pacific ocean. It is shown that the multivariate aspect of Br\textbf{B}_r brings additional information which substantially improves the identification procedure. Moreover the computational cost can be decreased by one order of magnitude with regard to the full-space 4D-Var method
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