Comment on Article by Ferreira and Gamerman

A utility-function approach to optimal spatial sampling design is a powerful way to quantify what "optimality" means. The emphasis then should be to capture all possible contributions to utility, including scientific impact and the cost of sampling. The resulting sampling plan should contain a component of designed randomness that would allow for a non-parametric design-based analysis if model-based assumptions were in doubt. [arXiv:1509.03410]Comment: Published at http://dx.doi.org/10.1214/15-BA944B in the Bayesian Analysis (http://projecteuclid.org/euclid.ba) by the International Society of Bayesian Analysis (http://bayesian.org/

Hardy-Muckenhoupt Bounds for Laplacian Eigenvalues

We present two graph quantities Psi(G,S) and Psi_2(G) which give constant factor estimates to the Dirichlet and Neumann eigenvalues, lambda(G,S) and lambda_2(G), respectively. Our techniques make use of a discrete Hardy-type inequality due to Muckenhoupt

Non-Gaussian bivariate modelling with application to atmospheric trace-gas inversion

Atmospheric trace-gas inversion is the procedure by which the sources and sinks of a trace gas are identified from observations of its mole fraction at isolated locations in space and time. This is inherently a spatio-temporal bivariate inversion problem, since the mole-fraction field evolves in space and time and the flux is also spatio-temporally distributed. Further, the bivariate model is likely to be non-Gaussian since the flux field is rarely Gaussian. Here, we use conditioning to construct a non-Gaussian bivariate model, and we describe some of its properties through auto- and cross-cumulant functions. A bivariate non-Gaussian, specifically trans-Gaussian, model is then achieved through the use of Box--Cox transformations, and we facilitate Bayesian inference by approximating the likelihood in a hierarchical framework. Trace-gas inversion, especially at high spatial resolution, is frequently highly sensitive to prior specification. Therefore, unlike conventional approaches, we assimilate trace-gas inventory information with the observational data at the parameter layer, thus shifting prior sensitivity from the inventory itself to its spatial characteristics (e.g., its spatial length scale). We demonstrate the approach in controlled-experiment studies of methane inversion, using fluxes extracted from inventories of the UK and Ireland and of Northern Australia.Comment: 45 pages, 7 figure

\u3cem\u3eIn Vitro\u3c/em\u3e Biosynthesis and Chemical Identification of UDP-\u3cem\u3eN\u3c/em\u3e-acetyl-d-quinovosamine (UDP-d-QuiNAc)

N-acetyl-d-quinovosamine (2-acetamido-2,6-dideoxy-d-glucose, QuiNAc) occurs in the polysaccharide structures of many Gram-negative bacteria. In the biosynthesis of QuiNAc-containing polysaccharides, UDP-QuiNAc is the hypothetical donor of the QuiNAc residue. Biosynthesis of UDP-QuiNAc has been proposed to occur by 4,6-dehydration of UDP-N-acetyl-d-glucosamine (UDP-GlcNAc) to UDP-2-acetamido-2,6-dideoxy-d-xylo-4-hexulose followed by reduction of this 4-keto intermediate to UDP-QuiNAc. Several specific dehydratases are known to catalyze the first proposed step. A specific reductase for the last step has not been demonstrated in vitro, but previous mutant analysis suggested that Rhizobium etli gene wreQ might encode this reductase. Therefore, this gene was cloned and expressed in Escherichia coli, and the resulting His6-tagged WreQ protein was purified. It was tested for 4-reductase activity by adding it and NAD(P)H to reaction mixtures in which 4,6-dehydratase WbpM had acted on the precursor substrate UDP-GlcNAc. Thin layer chromatography of the nucleotide sugars in the mixture at various stages of the reaction showed that WbpM converted UDP-GlcNAc completely to what was shown to be its 4-keto-6-deoxy derivative by NMR and that addition of WreQ and NADH led to formation of a third compound. Combined gas chromatography-mass spectrometry analysis of acid hydrolysates of the final reaction mixture showed that a quinovosamine moiety had been synthesized after WreQ addition. The two-step reaction progress also was monitored in real time by NMR. The final UDP-sugar product after WreQ addition was purified and determined to be UDP-d-QuiNAc by one-dimensional and two-dimensional NMR experiments. These results confirmed that WreQ has UDP-2-acetamido-2,6-dideoxy-d-xylo-4-hexulose 4-reductase activity, completing a pathway for UDP-d-QuiNAc synthesis in vitro

Late-Season High-Sedimentation Events in a Sediment Trap Record from Linnévatnet, Svalbard, Norway

Linnévatnet is a proglacial lake in the high Arctic, on the western coast of Spitsbergen, Svalbard, Norway. Svalbard’s climate is warm for its high latitude, with temperatures increasing in recent years and expected to continue rising. Given the longer and more intense melt season brought about by a warming climate, overall sedimentation may increase, and a large portion of that increase may be due to late summer and fall “shoulder season” storms falling as rain more often than as snow. This study utilizes the annual sediment trap record for the 2015-’16 accumulation year in order to document the effects of such late-season events on sedimentation in Linnévatnet, where sediment cores have yielded important high-resolution paleoclimate records. Sediment traps have been deployed in Linnévatnet since 2003, along with weather stations, time-lapse cameras, and an intervalometer, which records the timing of sediment deposition. Sediment traps are positioned to capture sediment in important zones of the lake, with special focus given to a transect from the primary inlet to the main basin. Studies of modern sedimentation patterns in the lake allow for better understanding and interpretation of sedimentary records of past climate. Meteorological and intervalometer data indicate that a rainstorm on September 11-12, 2015 yielded nearly 70% of the year’s total sediment. This contradicts the classic model of annually varved lake sediments, in which a nival flood of spring snowmelt carries most of the year’s sediment. Downcore profiles of grain size and XRF profiles of Ca, Zr, Fe, and K content distinguish sediment associated with the September rainstorm from that associated with the nival pulse. Sediment from the September rainstorm likely traveled in an irregular plume, not reaching all parts of the lake. Signatures of the nival pulse, however, were seen in all sediment traps, with some minor variations in composition representing variations in source lithology. With 70% of the year’s sediment associated with the September rainstorm, the characteristics unique to the fall storm had a significant influence on Linnévatnet’s sedimentation for the year. If shoulder season rainstorms are becoming more prevalent, it could drastically alter the sedimentation patterns in lakes like Linnévatnet

Pedagogical Virtues: An Account of the Intellectual Virtues of a Teacher

The overlap between virtue epistemology and the philosophy of education has been dominated by discussions of the epistemic qualities of good learners, that is, the intellectual virtues that must be nurtured in students. Not much has been said about the epistemic qualities of good teachers expressed in virtue-theoretic terms. This paper offers a preliminary account of such qualities, which are designated as pedagogical virtues. I use Battaly\u27s pluralist conception of intellectual virtue as a starting point, then describe a pedagogical virtue as an intellectual virtue with an other-regarding success or motivational component. I end with an elucidation of the pedagogical versions of two mainstream intellectual virtues, perseverance and inquisitiveness

Identification of taxonomic and functional ichthyofaunal zones within the James River Basin, Virginia

Environmental gradients structure ichthyofaunal communities longitudinally along river networks via the selective filtering of species’ traits. In many instances, these environmental influences have created distinct zones of co-occurring fish species. Zonation studies have most often been conducted with taxonomic data (species x site matrices), but the increasing availability of functional trait data creates an opportunity to build more rigorous understanding of species’ co-occurrence patterns. Notably, zonation studies that use taxonomic data may not reveal the same patterns as studies based on trait data. In this study, we tested for distinct ichthyofaunal zonation in James River Basin, VA using a combination of historical (1950-1987) and contemporary fish occurrence records (1986-2016) that were aggregated within 12-digit hydrologic units (HU). Zonation tests were performed separately for taxonomic data and functional trait data, using a combination of non-metric multidimensional scaling and k-means cluster analysis. We detected three distinct taxonomic zones and three functional trait zones within the James River Basin. In addition, through identifying that taxonomic dissimilarity between HUs was strongly correlated with functional dissimilarity, these zonation patterns were determined to not be significantly different

Simulations of the angular dependence of the dipole-dipole interaction among Rydberg atoms

The dipole-dipole interaction between two Rydberg atoms depends on the relative orientation of the atoms and on the change in the magnetic quantum number. We simulate the effect of this anisotropy on the energy transport in an amorphous many atom system subject to a homogeneous applied electric field. We consider two experimentally feasible geometries and find that the effects should be measurable in current generation imaging experiments. In both geometries atoms of $p$ character are localized to a small region of space which is immersed in a larger region that is filled with atoms of $s$ character. Energy transfer due to the dipole-dipole interaction can lead to a spread of $p$ character into the region initially occupied by $s$ atoms. Over long timescales the energy transport is confined to the volume near the border of the $p$ region which is suggestive of Anderson localization. We calculate a correlation length of 6.3~$\mu$m for one particular geometry.Comment: 6 pages, 5 figures, revised draf