The effect of small concentrations of intracrystalline water on the strength of olivine is significant at asthenospheric temperatures but is poorly constrained at lower temperatures applicable to the ...shallow lithosphere. We examined the effect of water on the yield stress of olivine during low‐temperature plasticity using room‐temperature Berkovich nanoindentation. The presence of water in olivine (1,600 ppm H/Si) does not affect hardness or yield stress relative to dry olivine (≤40 ppm H/Si) outside of uncertainty but may slightly reduce Young’s modulus. Differences between water‐bearing and dry crystals in similar orientations were minor compared to differences between dry crystals in different orientations. These observations suggest water content does not affect the strength of olivine at low homologous temperatures. Thus, intracrystalline water does not play a role in olivine deformation at these temperatures, implying that water does not lead to weakening in the coldest portions of the mantle.
Plain Language Summary
At high temperatures (>1,000°C), incorporating small amounts of water in a crystalline structure can dramatically affect the strength of that crystal. There are many theories as to why this is the case, and each theory makes a prediction for how water might affect the strength of crystals at low temperatures. Thus, by conducting experiments at room temperature, we can distinguish between some of these theories. Our data indicate that water does not have a significant effect on the strength of olivine at room temperature, and any minor effect that water may have is far outweighed by the effect of crystal orientation. These observations rule out theories in which water causes a decrease in the strength of olivine at all temperatures, implying that water does not lead to weakening in the coldest portions of the mantle.
Key Points
Room‐temperature nanoindentation tests on wet and dry olivine yield very similar mechanical results
Any effect of water incorporation on yield stress is outweighed by the effect of orientation anisotropy
Water may only weaken olivine at high temperatures and therefore not influence strength in the coldest portions of the lithosphere
Bright gravitationally lensed galaxies provide our most detailed view of galaxies at high redshift. The very brightest (r < 21) systems enable high spatial and spectral resolution measurements, ...offering unique constraints on the outflow energetics, metallicity gradients and stellar populations in high-redshift galaxies. Yet as a result of the small number of ultrabright z 2 lensed systems with confirmed redshifts, most detailed spectroscopic studies have been limited in their scope. With the goal of increasing the number of bright lensed galaxies available for detailed follow-up, we have undertaken a spectroscopic campaign targeting wide separation ( 3 arcsec) galaxy-galaxy lens candidates within the Sloan Digital Sky Survey (SDSS). Building on the earlier efforts of our Cambridge and Sloan Survey Of Wide Arcs in Thesky survey, we target a large sample of candidate galaxy-galaxy lens systems in SDSS using a well-established search algorithm which identifies blue arc-like structures situated around luminous red galaxies. In this paper, we present a new redshift catalogue containing 29 lensed sources in SDSS confirmed through spectroscopic follow-up of candidate galaxy-galaxy lens systems. Included in this new sample are two of the brightest galaxies (r = 19.6 and 19.7) known at z 2, a low metallicity (12 + log (O/H) 8.0) extreme nebular line emitting galaxy at z = 1.43, and numerous systems for which detailed follow-up will be possible. The source redshifts span 0.9 < z < 2.5 (median redshift of 1.9), and their optical magnitudes are in the range 19.6 r 22.3. We present a brief source-by-source discussion of the spectroscopic properties extracted from our confirmatory spectra and discuss some initial science results. Preliminary lens modelling reveals average source magnifications of 5-10 times. With more than 50 gravitationally lensed z 1 galaxies now confirmed within SDSS, it will soon be possible for the first time to develop generalized conclusions from detailed spectroscopic studies of the brightest lensed systems at high redshift.
We analyse the density field of galaxies observed by the Sloan Digital Sky Survey (SDSS)-III Baryon Oscillation Spectroscopic Survey (BOSS) included in the SDSS Data Release Nine (DR9). DR9 includes ...spectroscopic redshifts for over 400 000 galaxies spread over a footprint of 3275 deg2. We identify, characterize and mitigate the impact of sources of systematic uncertainty on large-scale clustering measurements, both for angular moments of the redshift-space correlation function, ξℓ(s), and the spherically averaged power spectrum, P(k), in order to ensure that robust cosmological constraints will be obtained from these data. A correlation between the projected density of stars and the higher redshift (0.43 < z < 0.7) galaxy sample (the approximately constant stellar mass threshold 'CMASS' sample) due to imaging systematics imparts a systematic error that is larger than the statistical error of the clustering measurements at scales s > 120 h
−1 Mpc or k < 0.01 h Mpc−1. We find that these errors can be ameliorated by weighting galaxies based on their surface brightness and the local stellar density. The clustering of CMASS galaxies found in the Northern and Southern Galactic footprints of the survey generally agrees to within 2σ. We use mock galaxy catalogues that simulate the CMASS selection function to determine that randomly selecting galaxy redshifts in order to simulate the radial selection function of a random sample imparts the least systematic error on ξℓ(s) measurements and that this systematic error is negligible for the spherically averaged correlation function, ξ0. We find a peak in ξ0 at s∼ 200 h
−1 Mpc, with a corresponding feature with period ∼0.03 h Mpc−1 in P(k), and find features at least as strong in 4.8 per cent of the mock galaxy catalogues, concluding this feature is likely to be a consequence of cosmic variance. The methods we recommend for the calculation of clustering measurements using the CMASS sample are adopted in companion papers that locate the position of the baryon acoustic oscillation feature, constrain cosmological models using the full shape of ξ0 and measure the rate of structure growth.
Climate change is resulting in rapid poleward shifts in the geographical distribution of many tropical fish species, but it is equally apparent that some fishes are failing to exhibit expected shifts ...in their geographical distribution. There is still little understanding of the species‐specific traits that may constrain or promote successful establishment of populations in temperate regions. We review the factors likely to affect population establishment, including larval supply, settlement and post‐settlement processes. In addition, we conduct meta‐analyses on existing and new data to examine relationships between species‐specific traits and vagrancy. We show that tropical vagrant species are more likely to originate from high‐latitude populations, while at the demographic level, tropical fish species with large body size, high swimming ability, large size at settlement and pelagic spawning behaviour are more likely to show successful settlement into temperate habitats. We also show that both habitat and food limitation at settlement and within juvenile stages may constrain tropical vagrant communities to those species with medium to low reliance on coral resources.
Timely and accurate detection and estimation of animal abundance is an important part of wildlife management. This is particularly true for invasive species where cost-effective tools are needed to ...enable landscape-scale surveillance and management responses, especially when targeting low-density populations residing in dense vegetation and under canopies. This research focused on investigating the feasibility and practicality of using uncrewed aerial systems (UAS) and hyperspectral imagery (HSI) to classify animals in the wild on a spectral—rather than spatial—basis, in the hopes of developing methods to accurately classify animal targets even when their form may be significantly obscured. We collected HSI of four species of large mammals reported as invasive species on islands: cow (Bos taurus), horse (Equus caballus), deer (Odocoileus virginianus), and goat (Capra hircus) from a small UAS. Our objectives of this study were to (a) create a hyperspectral library of the four mammal species, (b) study the efficacy of HSI for animal classification by only using the spectral information via statistical separation, (c) study the efficacy of sequential and deep learning neural networks to classify the HSI pixels, (d) simulate five-band multispectral data from HSI and study its effectiveness for automated supervised classification, and (e) assess the ability of using HSI for invasive wildlife detection. Image classification models using sequential neural networks and one-dimensional convolutional neural networks were developed and tested. The results showed that the information from HSI derived using dimensionality reduction techniques were sufficient to classify the four species with class F1 scores all above 0.85. The performances of some classifiers were capable of reaching an overall accuracy over 98%and class F1 scores above 0.75, thus using only spectra to classify animals to species from existing sensors is feasible. This study discovered various challenges associated with the use of HSI for animal detection, particularly intra-class and seasonal variations in spectral reflectance and the practicalities of collecting and analyzing HSI data over large meaningful areas within an operational context. To make the use of spectral data a practical tool for wildlife and invasive animal management, further research into spectral profiles under a variety of real-world conditions, optimization of sensor spectra selection, and the development of on-board real-time analytics are needed.
Abstract OBJECTIVE To determine the prevalence and spectrum of mutations associated with long QT syndrome (LQTS) and catecholaminergic polymorphic ventricular tachycardia (CPVT) in a seemingly ...unexplained drowning cohort. PATIENTS AND METHODS From September 1, 1998, through October 31, 2010, 35 unexplained drowning victims (23 male and 12 female; mean ± SD age, 17±12 years range, 4-69 years) were referred for a cardiac channel molecular autopsy. Of these, 28 (20 male and 8 female) drowned while swimming, and 7 (3 male and 4 female) were bathtub submersions. Polymerase chain reaction, denaturing high-performance liquid chromatography, and DNA sequencing were used for a comprehensive mutational analysis of the 3 major LQTS-susceptibility genes (KCNQ1, KCNH2, and SCN5A), and a targeted analysis of the CPVTl-associated, RYR2- encoded cardiac ryanodine receptor was conducted. RESULTS Of the 28 victims of swimming-related drowning, 8 (28.6%) were mutation positive, including 2 with KCNQ1 mutations (L273F, AAPdel71-73 plus V524G) and 6 with RYR2 mutations (R414C, I419F, R1013Q, V2321A, R2401H, and V2475F). None of the bathtub victims were mutation positive. Of the 28 victims who drowned while swimming, women were more likely to be mutation positive than men (5/8 62.5% vs 3/20 15%; P=.02). Although none of the mutation-positive, swimming-related drowning victims had a premortem diagnosis of LQTS or CPVT, a family history of cardiac arrest, family history of prior drowning, or QT prolongation was present in 50%. CONCLUSION Nearly 30% of the victims of swimming-related drowning hosted a cardiac channel mutation. Genetic testing should be considered in the postmortem evaluation of an unexplained drowning, especially if a positive personal or family history is elicited.
We present a study of galaxy clustering using 900,000 luminous galaxies with photometric redshifts, spanning between z = 0.45 and z = 0.65, constructed from the SDSS using methods described in Ross ...et al. We describe in detail the construction of the survey window function and various systematics affecting our measurement. We present a novel treatment of the observational systematics and its applications to the clustering signals from the data set. We also apply corrections to the power spectra due to systematics and derive cosmological constraints using the full shape of the power spectra. We also find that systematic-corrected power spectra give consistent constraints on cosmological models when compared with pre-systematic correction power spectra in the angular scales of interest.
Surface plasmon has the unique capability to concentrate light into subwavelength volume. − Active plasmon devices using electrostatic gating can enable flexible control of the plasmon excitations, ...which has been demonstrated recently in terahertz plasmonic structures. − Controlling plasmon resonance at optical frequencies, however, remains a significant challenge because gate-induced free electrons have very weak responses at optical frequencies. Here we achieve efficient control of near-infrared plasmon resonance in a hybrid graphene-gold nanorod system. Exploiting the uniquely strong , and gate-tunable optical transitions , of graphene, we are able to significantly modulate both the resonance frequency and quality factor of gold nanorod plasmon. Our analysis shows that the plasmon–graphene coupling is remarkably strong: even a single electron in graphene at the plasmonic hotspot could have an observable effect on plasmon scattering intensity. Such hybrid graphene–nanometallic structure provides a powerful way for electrical control of plasmon resonances at optical frequencies and could enable novel plasmonic sensing down to single charge transfer events.
While dietary factors are important modifiable risk factors for type 2 diabetes (T2D), the causal role of carbohydrate quality in nutrition remains controversial. Dietary glycemic index (GI) and ...glycemic load (GL) have been examined in relation to the risk of T2D in multiple prospective cohort studies. Previous meta-analyses indicate significant relations but consideration of causality has been minimal. Here, the results of our recent meta-analyses of prospective cohort studies of 4 to 26-y follow-up are interpreted in the context of the nine Bradford-Hill criteria for causality, that is: (1) Strength of Association, (2) Consistency, (3) Specificity, (4) Temporality, (5) Biological Gradient, (6) Plausibility, (7) Experimental evidence, (8) Analogy, and (9) Coherence. These criteria necessitated referral to a body of literature wider than prospective cohort studies alone, especially in criteria 6 to 9. In this analysis, all nine of the Hill's criteria were met for GI and GL indicating that we can be confident of a role for GI and GL as causal factors contributing to incident T2D. In addition, neither dietary fiber nor cereal fiber nor wholegrain were found to be reliable or effective surrogate measures of GI or GL. Finally, our cost-benefit analysis suggests food and nutrition advice favors lower GI or GL and would produce significant potential cost savings in national healthcare budgets. The high confidence in causal associations for incident T2D is sufficient to consider inclusion of GI and GL in food and nutrient-based recommendations.
We analyse the density field of 264 283 galaxies observed by the Sloan Digital Sky Survey (SDSS)-III Baryon Oscillation Spectroscopic Survey (BOSS) and included in the SDSS Data Release 9 (DR9). In ...total, the SDSS DR9 BOSS data include spectroscopic redshifts for over 400 000 galaxies spread over a footprint of more than 3000 deg2. We measure the power spectrum of these galaxies with redshifts 0.43 < z < 0.7 in order to constrain the amount of local non-Gaussianity, , in the primordial density field, paying particular attention to the impact of systematic uncertainties. The BOSS galaxy density field is systematically affected by the local stellar density and this influences the ability to accurately measure . In the absence of any correction, we find (erroneously) that the probability that is greater than zero, P( > 0), is 99.5 per cent. After quantifying and correcting for the systematic bias and including the added uncertainty, we find − 45 < < 195 at 95 per cent confidence and P( > 0) = 91.0 per cent. A more conservative approach assumes that we have only learnt the k dependence of the systematic bias and allows any amplitude for the systematic correction; we find that the systematic effect is not fully degenerate with that of , and we determine that −82 < < 178 (at 95 per cent confidence) and P( > 0) = 68 per cent. This analysis demonstrates the importance of accounting for the impact of Galactic foregrounds on measurements. We outline the methods that account for these systematic biases and uncertainties. We expect our methods to yield robust constraints on for both our own and future large-scale structure investigations.
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