3,394 research outputs found
How to Incorporate Non-Epistemic Values into a Theory of Classification
Non-epistemic values play important roles in classificatory practice, such that philosophical accounts of kinds and classification should be able to accommodate them. Available accounts fail to do so, however. Our aim is to fill this lacuna by showing how non-epistemic values feature in scientific classification, and how they can be incorporated into a philosophical theory of classification and kinds. To achieve this, we present a novel account of kinds and classification (the Grounded Functionality Account), discuss examples from biological classification where non-epistemic values play decisive roles, and show how this account accommodates the role of non-epistemic values. © 2022, The Author(s)
Fungi Associated with Dieback and Pruning Wounds of Grapevines in South Africa
Isolations were made from discoloured tissue of grapevines showing dieback symptoms in the winter rainfall region. Fifteen fungal species were isolated, of which Sphaeropsis sp. Fusarium oxysporum, Eutypa lata (anamorph: Libertella blepharis A.L. Smith), Pestalotia quepini and Botrytis cinerea could be designated as parasites. E. lata was the most probable cause of the dieback phenomenon. Additional isolates representing ten fungal genera were isolated from discoloured wood in spurs from visually healthy grapevines while organisms representing 14 genera were isolated from lesions in grapevines exhibiting dieback symptoms. Aspergillus sp. was more common in the healthy and marginal zones while Sphaeropsis sp. occurred more often in the healthy zone and Phylosticta sp. in the discoloured zone of pruning stubs. In lesions from vines with dieback symptoms, Altemaria alternata was isolated more regularly from the marginal zone between healthy and discoloured wood, while E. lata and Trichoderma harzianum were isolated more often from the older part of the lesion. A succession of fungi in the colonisation of pruning wounds and in dieback lesions is suggested
Metal Abundance Calibration of the Ca II Triplet Lines in RR Lyrae Stars
The GAIA satellite is likely to observe thousands of RR Lyrae stars within a
small spectral window, between 8470A and 8750A, at a resolution of 11,500. In
order to derive the metallicity of RR Lyrae stars from Gaia, we have obtained
numerous spectra of RR Lyrae stars at a resolution of 35,000 with the Apache
Point Observatory 3.5 m echelle spectrograph. We have correlated the Ca II
triplet line strengths with metallicity as derived from Fe II abundances,
analogous to Preston's (1959) use of the Ca II K line to estimate the
metallicity of RR Lyrae stars. The Ca II line at 8498A is the least blended
with neighboring Paschen lines and thus provides the best correlation.Comment: Accepted for publication in Astrophysics & Space Scienc
A survey on the quality of Indian fish meal of commerce
Data on proximate composition, total volatile bases, total non-protein nitrogen and bacterial quality of commercial samples of Indian fish meal are presented in this communication. The samples vary very much in quality depending on the type of raw material used and method of processing followed. The data are discussed in relation to the Indian standard Specifications for fish meal as livestock feed
NNLO fermionic corrections to the charm quark mass dependent matrix elements in B -> X_s gamma
We compute the virtual O(alpha_s^2) fermionic contributions to the charm
quark mass dependent matrix elements of the B -> X_s gamma decay. In the case
of a massless quark loop insertion into the gluon propagator, our result
obtained as an expansion in z=m_c^2/m_b^2 and an exact expression in terms of
multi-fold MB integrals, confirms the findings of Bieri, Greub and Steinhauser
[19]. We observe, however, large deviations in the case of a b-quark loop
insertion.The charm quark loop shows smaller, but still noticeable differences.Comment: 11 pages, 3 figures, 1 tabl
Blue emitting gold nanoclusters templated by poly-cytosine DNA at low pH and poly-adenine DNA at neutral pH
Blue fluorescent gold nanoclusters were prepared in the presence of poly-cytosine DNAs at low pH and poly-adenine at neutral pH using citrate as the reducing agent; various buffer conditions affecting the synthesis have been explored.University of Waterloo ||
Canadian Foundation for Innovation ||
Natural Sciences and Engineering Research Council ||
Ontario Ministry of Research and Innovation |
Methane adsorption on shale under simulated geological temperature and pressure conditions
Shale gas is becoming an increasingly important energy resource. In this study, the adsorption of methane on a dry, organic-rich Alum shale sample was studied at pressures up to 14 MPa and temperatures in the range 300–473 K, which are relevant to gas storage under geological conditions. Maximum methane excess uptake was 0.176–0.042 mmol g–1 (125–30 scf t–1) for the temperature range of 300–473 K. The decrease in maximum methane surface excess with increasing temperature can be described with a linear model. An isosteric enthalpy of adsorption 19.2 ± 0.1 kJ mol–1 was determined at 0.025 mmol g–1 using the van’t Hoff equation. Supercritical adsorption was modeled using the modified Dubinin–Radushkevich and the Langmuir equations. The results are compared with absolute isotherms calculated from surface excess and the pore volumes obtained from subcritical gas adsorption (nitrogen (78 K), carbon dioxide (273 and 195 K), and CH4 (112 K)). The subcritical adsorption and the surface excess results allow an upper limit to be put on the amount of gas that can be retained by adsorption during gas generation from petroleum source rocks
High-pressure methane adsorption and characterization of pores in Posidonia shales and isolated kerogens
Sorption capacities and pore characteristics of bulk shales and isolated kerogens have been determined for immature, oil-window, and gas-window mature samples from the Lower Toarcian Posidonia shale formation. Dubinin–Radushkevich (DR) micropore volumes, sorption pore volumes, and surface areas of shales and kerogens were determined from CO2 adsorption isotherms at −78 and 0 °C, and from N2 adsorption isotherms at −196 °C. Mercury injection capillary pressure porosimetry, grain density measurements, and helium pycnometry were used to determine shale and kerogen densities and total pore volumes. Total porosities decrease through the oil-window and then increase into the gas-window. High-pressure methane isotherms up to 14 MPa were determined at 45, 65, and 85 °C on dry shale and at 45 and 65 °C on kerogen. Methane excess uptakes at 65 °C and 11.5 MPa were in the range 0.056–0.110 mmol g–1 (40–78 scf t–1) for dry Posidonia shales and 0.36–0.70 mmol g–1 (253–499 scf t–1) for the corresponding dry kerogens. Absolute methane isotherms were calculated by correcting for the gas at bulk gas phase density in the sorption pore volume. The enthalpies of CH4 adsorption for shales and kerogens at zero surface coverage showed no significant variation with maturity, indicating that the sorption pore volume is the primary control on sorption uptake. The sum of pore volumes measured by (a) CO2 sorption at −78 °C and (b) mercury injection, are similar to the total porosity for shales. Since mercury in our experiments occupies pores with constrictions larger than ca. 6 nm, we infer that porosity measured by CO2 adsorption at −78 °C in the samples used in this study is largely within pores with effective diameters smaller than 6 nm. The linear correlation between maximum CH4 surface excess sorption and CO2 sorption pore volume at −78 °C is very strong for both shales and kerogens, and goes through the origin, suggesting that the vast majority of sorbed CH4 occurs in pores smaller than 6 nm. The DR micropore volume obtained from CO2 adsorption at 0 °C was 40%–62% of the corresponding CO2 sorption pore volume. Sorption mass balances using kerogen and shale isotherms showed that approximately half of the CO2 sorption in these dry shales is in organic matter, with the rest likely to be associated with the inorganic phase (mainly clay minerals). A similar distribution was observed for supercritical CH4 adsorption. Mass balances for adsorption isotherms for kerogen and clay minerals do not always account for the total measured sorbed CH4 on dry shales, suggesting that some sorption may not be completely accounted for by the minerals identified and kerogens in the shales
Enhancing the Safety Training of Aviators to Mitigate the Risk of Bird Strikes: A Scientific Approach
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