2,289 research outputs found

    An all soft, electro-pneumatic controller for soft robots

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    Uā€“Pb Zircon Ages, Mapping, and Biostratigraphy of the Payette Formation and Idaho Group North of the Western Snake River Plain, Idaho: Implications for Hydrocarbon System Correlation

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    Sedimentary deposits north of the western Snake River Plain host Idahoā€™s first and only producing oil and gas field. They consist of the lower to middle Miocene Payette Formation, the middle to upper Miocene Poison Creek and Chalk Hills Formations, and the Pliocene to lower Pleistocene Glenns Ferry Formation. Using new geochronology, palynomorph biostratigraphy, and geologic mapping, we connect updip surface features to subsurface petroleum play elements. The Payette Formation is a likely main source of the hydrocarbons, and acts as one of the reservoirs in the unnamed basin. Here, we redefine the Payette Formation as 0 to ~3,500 ft (0 to ~1,000 m) of mudstone, with lesser amounts of sandstone overlying and interbedded with the Columbia River Basalt Group and Weiser volcanic field. Index palynomorphs, including Liquidambar and Pterocarya, present in Idaho during and immediately after the middle Miocene climatic optimum, and new Uā€“Pb ages of 16.39 and 15.88 Ma, help establish the thickness and extent of the formation. For the first time, these biostratigraphic markers have been defined for the oil and gas wells. The Poison Creek Formation is sandstone interbedded with mudstone that is ~800ā€“1,800 ft (250ā€“550 m) thick. The Chalk Hills Formation is a tuffaceous siltstone, claystone, and sandstone that is as much as ~4,200 ft (1,280 m) thick. New Uā€“Pb ages are 10.1, 9.04, and 9.00 for the Poison Creek Formation, along with maximum depositional ages of 10.7 to 9.9 Ma for four samples from the Poison Creek Formation. A single Uā€“Pb age of 7.78 Ma was determined from pumice low in the Chalk Hills Formation. Like the Payette Formation, the Poison Creek Formation can be a reservoir, whereas the Chalk Hills Formation acts as a sealing mudstone facies. The overlying sandstone, siltstone, and conglomerate of the Glenns Ferry Formation act as the overburden to the petroleum system in the subsurface, and were important for burial and hydrocarbon maturation. The Glenns Ferry Formation is up to 500 ft (150 m) thick in the study area, as much has been eroded. Whereas the Payette and Poison Creek Formations were deposited during the mid-Miocene climatic optimum amongst and above volcanic flows, the Chalk Hills and Glenns Ferry Formations were deposited within ancient Lake Idaho during an overall increase in aridity and cooling after the mid-Miocene climatic optimum

    The combined use of selective deuteration and double resonance experiments in assigning the 1H resonances of valine and tyrosine residues of dihydrofolate reductase

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    AbstractSelective deuteration is a general solution to the resolution problem which limits the application of double resonance experiments to the assignment of the 1H NMR spectra of proteins. Spin-decoupling and NOE experiments have been carried out on Lactobacillus casei dihydrofolate reductase and on selectively deuterated derivatives of the enzyme containing either [Ī³-2H6]Val or (Ī±,Ī“2,Ļµ1-2H3]His, [Ī±,Ī“1,Ī“2,Ļµ1,Ļµ2,Ī¶-2H6]Phe, [Ī±,Ī“1,Ļµ3,Ī¶2,Ī¶3,Ī·2-2H6]Trp and [Ī±,Ļµ1,Ļµ2-2H3]Tyr. When combined with ring-current shift calculations based on the crystal structure of the enzyme, these experiments allow us to assign 1H resonances of Val 61, Val 115, Tyr 46 and Tyr 68

    Wavelet-Bayesian inference of cosmic strings embedded in the cosmic microwave background

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    Cosmic strings are a well-motivated extension to the standard cosmological model and could induce a subdominant component in the anisotropies of the cosmic microwave background (CMB), in addition to the standard inflationary component. The detection of strings, while observationally challenging, would provide a direct probe of physics at very high energy scales. We develop a new framework for cosmic string inference, constructing a Bayesian analysis in wavelet space where the string-induced CMB component has distinct statistical properties to the standard inflationary component. Our wavelet-Bayesian framework provides a principled approach to compute the posterior distribution of the string tension GĪ¼G\mu and the Bayesian evidence ratio comparing the string model to the standard inflationary model. Furthermore, we present a technique to recover an estimate of any string-induced CMB map embedded in observational data. Using Planck-like simulations we demonstrate the application of our framework and evaluate its performance. The method is sensitive to GĪ¼āˆ¼5Ɨ10āˆ’7G\mu \sim 5 \times 10^{-7} for Nambu-Goto string simulations that include an integrated Sachs-Wolfe (ISW) contribution only and do not include any recombination effects, before any parameters of the analysis are optimised. The sensitivity of the method compares favourably with other techniques applied to the same simulations.Comment: 18 pages, 14 figures, minor changes to match version accepted by MNRA

    Liesegang patterns: Effect of dissociation of the invading electrolyte

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    The effect of dissociation of the invading electrolyte on the formation of Liesegang bands is investigated. We find, using organic compounds with known dissociation constants, that the spacing coefficient, 1+p, that characterizes the position of the n-th band as x_n ~ (1+p)^n, decreases with increasing dissociation constant, K_d. Theoretical arguments are developed to explain these experimental findings and to calculate explicitly the K_d dependence of 1+p.Comment: RevTex, 8 pages, 3 eps figure

    3D enamel thickness in Neandertal and modern human permanent canines

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    Enamel thickness figures prominently in studies of human evolution, particularly for taxonomy, phylogeny, and paleodietary reconstruction. Attention has focused on molar teeth, through the use of advanced imaging technologies and novel protocols. Despite the important results achieved thus far, further work is needed to investigate all tooth classes. We apply a recent approach developed for anterior teeth to investigate the 3D enamel thickness of Neandertal and modern human (MH) canines. In terms of crown size, the values obtained for both upper and lower unworn/slightly worn canines are significantly greater in Neandertals than in Upper Paleolithic and recent MH. The 3D relative enamel thickness (RET) is significantly lower in Neandertals than in MH. Moreover, differences in 3D RET values between the two groups appear to decrease in worn canines beginning from wear stage 3, suggesting that both the pattern and the stage of wear may have important effects on the 3D RET value. Nevertheless, the 3D average enamel thickness (AET) does not differ between the two groups. In both groups, 3D AET and 3D RET indices are greater in upper canines than in lower canines, and overall the enamel is thicker on the occlusal half of the labial aspect of the crown, particularly in MH. By contrast, the few early modern humans investigated show the highest volumes of enamel while for all other components of 3D enamel, thickness this group holds an intermediate position between Neandertals and recent MH. Overall, our study supports the general findings that Neandertals have relatively thinner enamel than MH (as also observed in molars), indicating that unworn/slightly worn canines can be successfully used to discriminate between the two groups. Further studies, however, are needed to understand whether these differences are functionally related or are the result of pleiotropic or genetic drift effects
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