2,341 research outputs found
Design effects in a meta-analysis of river health choice experiments in Australia
Rolfe, JC ORCiD: 0000-0001-7659-7040While meta-analysis is typically used to identify value estimates for benefit transfer, applications also provide insights into the potential influence of methodological design characteristics on results of non-market valuation experiments. In this paper, a meta-analysis of nineteen choice modeling (CM) studies in Australia is conducted generating 145 individual value estimates relating to river health. Implicit prices of different measures and scales of river health were transformed into a common standard of willingness to pay (WTP) per kilometer of river in good health. A Tobit model was used to identify the relationships between this dependent variable and a large number of study design characteristics. While there is evidence that the dimensions of choice tasks and description of attributes influence value estimates, there is also evidence that the way tradeoffs and payment mechanisms are framed are equally important. The results of this meta analysis suggest that more attention should be paid to the way tradeoffs are framed in choice experiments relative to internal choice set structure and data analysis
Laser-Doppler gas-velocity instrument
Three-D instrument using a laser light source measures both turbulence and mean velocity of subsonic and supersonic gas flows. This instrument is based on the measurement of the Doppler frequency shift of light waves scattered by moving particles in the gas stream
How to evaluate multiple range-sum queries progressively
Decision support system users typically submit batches of range-sum queries simultaneously rather than issuing individual, unrelated queries. We propose a wavelet based technique that exploits I/O sharing across a query batch to evaluate the set of queries progressively and efficiently. The challenge is that now controlling the structure of errors across query results becomes more critical than minimizing error per individual query. Consequently, we define a class of structural error penalty functions and show how they are controlled by our technique. Experiments demonstrate that our technique is efficient as an exact algorithm, and the progressive estimates are accurate, even after less than one I/O per query
Understanding the role of electron and hole trions on current transport in aluminium tris(8-hydroxyquinoline) using organic magnetoresistance
Microwave-assisted sequential one-pot protocol to benzothiadiazin-3-one-1,1-dioxides via a copper-catalyzed N-arylation strategy
A microwave-assisted, sequential, one-pot protocol has been developed for the synthesis of a variety of benzothiadiazin-3-one-1,1-dioxides. This protocol utilizes a copper-catalyzed N-arylation of α-bromo-benzenesulfonamides with a number of amines to generate the corresponding 2-aminobenzenesulfonamides, which undergo cyclization to the desired sultams using carbonyl diimidazole (CDI). A range of conditions was evaluated for the key C–N bond formation step with tolerance toward functionalized amines
Laser Doppler velocity instrument
Laser Doppler velocity instrument for measuring turbulence and mean velocity in subsonic and supersonic gas flow
Transcriptional profiling of colicin-induced cell death of Escherichia coli MG1655 identifies potential mechanisms by which bacteriocins promote bacterial diversity
We report the transcriptional response of Escherichia coli MG1655 to damage induced by colicins E3 and E9, bacteriocins that kill cells through inactivation of the ribosome and degradation of chromosomal DNA, respectively. Colicin E9 strongly induced the LexA-regulated SOS response, while colicin E3 elicited a broad response that included the induction of cold shock genes, symptomatic of translational arrest. Colicin E3 also increased the transcription of cryptic prophage genes and other laterally acquired mobile elements. The transcriptional responses to both these toxins suggest mechanisms that may promote genetic diversity in E. coli populations, pointing to a more general role for colicins in adaptive bacterial physiology than has hitherto been realized
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Mars simulated exposure and the characteristic Raman biosignatures of amino acids and halophilic microbes
Though Raman bands of α-amino acids (AA) are well documented, often only the strongest intensity bands are quoted as identifiers (e.g. Jenkins et al., 2005; De Gelder et al., 2007; Zhu et al., 2011). Unknown regolith mixtures on Mars-sampling missions could obscure these bands. Here the case is made for determining, via a statistical method, sets of characteristic bands to be used as identifiers, independent of band intensity or number of bands (Rolfe et al., 2016). AA have upwards of 25 potentially identifying bands and this method defines sets of 10–19 bands per AA. Examination of AA-doped Mars-like basalt resulted in a maximum of eight bands being identified, as some characteristic bands were obscured by mineral bands, including the strongest intensity band in some cases. This proved the need for characteristic bands to be defined, enabling successful identification of AA. The ESA ExoMars Rover mission will crush and then pass the sample to the Raman Laser Spectrometer. We crushed a Mars-like basalt to a similar grain size expected to be created by the rover. Our samples were doped with 1 % (by weight) AA samples, resulting in no detection of AA, because of loss of original spatial context and spaces between the grains. We recommend that Raman spectroscopy on future missions should be conducted before the sample is crushed. Halite-entombed halophilic microbes, known to survive being entombed, were exposed to Mars-like surface (including temperature, pressure, atmospheric composition and UV) and freeze-thaw cycle (plus pressure and atmospheric composition) conditions. This test on the survival of the microbes showed that survival rates quickly deteriorated in surface conditions, but freeze-thaw cycle samples had well preserved Raman biosignatures, indicating that similar signatures could be detectable on Mars if similar life persists in evaporitic material or brines today
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