1,972 research outputs found

    Low Pressure Ethenolysis of Renewable Methyl Oleate in a Microchemical System

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    A microchemical system for ethenolysis of renewable methyl oleate was developed, in which the dual-phase, microfluidic design enabled efficient diffusion of ethylene gas into liquid methyl oleate through an increased contact area. The increased mass transfer of ethylene favored the formation of desired commodity chemicals with significantly suppressed homometathesis when compared to the bulk system. In addition to higher selectivity and conversion, this system also provides the typical advantages of a microchemical system, including the possibility of convenient scale-up

    Constructing a simulation surrogate with partially observed output

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    Gaussian process surrogates are a popular alternative to directly using computationally expensive simulation models. When the simulation output consists of many responses, dimension-reduction techniques are often employed to construct these surrogates. However, surrogate methods with dimension reduction generally rely on complete output training data. This article proposes a new Gaussian process surrogate method that permits the use of partially observed output while remaining computationally efficient. The new method involves the imputation of missing values and the adjustment of the covariance matrix used for Gaussian process inference. The resulting surrogate represents the available responses, disregards the missing responses, and provides meaningful uncertainty quantification. The proposed approach is shown to offer sharper inference than alternatives in a simulation study and a case study where an energy density functional model that frequently returns incomplete output is calibrated.Comment: submitted to Technometric

    The failure of stellar feedback, magnetic fields, conduction, and morphological quenching in maintaining red galaxies

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    The quenching "maintenance'" and related "cooling flow" problems are important in galaxies from Milky Way mass through clusters. We investigate this in halos with masses 10121014M\sim 10^{12}-10^{14}\,{\rm M}_{\odot}, using non-cosmological high-resolution hydrodynamic simulations with the FIRE-2 (Feedback In Realistic Environments) stellar feedback model. We specifically focus on physics present without AGN, and show that various proposed "non-AGN" solution mechanisms in the literature, including Type Ia supernovae, shocked AGB winds, other forms of stellar feedback (e.g. cosmic rays), magnetic fields, Spitzer-Braginskii conduction, or "morphological quenching" do not halt or substantially reduce cooling flows nor maintain "quenched" galaxies in this mass range. We show that stellar feedback (including cosmic rays from SNe) alters the balance of cold/warm gas and the rate at which the cooled gas within the galaxy turns into stars, but not the net baryonic inflow. If anything, outflowing metals and dense gas promote additional cooling. Conduction is important only in the most massive halos, as expected, but even at 1014M\sim 10^{14}\,{\rm M}_{\odot} reduces inflow only by a factor 2\sim 2 (owing to saturation effects and anisotropic suppression). Changing the morphology of the galaxies only slightly alters their Toomre-QQ parameter, and has no effect on cooling (as expected), so has essentially no effect on cooling flows or maintaining quenching. This all supports the idea that additional physics, e.g., AGN feedback, must be important in massive galaxies.Comment: 16 pages, 12 figure

    An Integrated Content and Metadata based Retrieval System for Art

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    In this paper we describe aspects of the Artiste project to develop a distributed content and metadata based analysis, retrieval and navigation system for a number of major European Museums. In particular, after a brief overview of the complete system, we describe the design and evaluation of some of the image analysis algorithms developed to meet the specific requirements of the users from the museums. These include a method for retrievals based on sub images, retrievals based on very low quality images and retrieval using craquelure type

    Diet and exercise advice and referrals for cancer survivors: An integrative review of medical and nursing perspectives

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    Purpose: To examine the perspectives of medical and nursing health professionals concerning their roles and responsibilities in providing dietary and exercise advice to cancer survivors, and referrals to allied health professionals. Methods: An integrative review. PubMed, CINAHL, PsycINFO, Embase, Web of Science databases, and bibliographies of relevant studies were searched from December 2011 to June 2021. All studies were eligible for inclusion. The Mixed-Methods Appraisal Tool (MMAT) was used to critically appraise included studies. Data were extracted and synthesised regarding the perspectives of medical and nursing health professionals on their roles, responsibilities, barriers, and facilitators. Results: Twenty-one studies involving 3401 medical and nursing health professionals and 264 cancer survivors of diverse cancer types were included. Ten quantitative, nine qualitative, and two mixed-methods studies were eligible. All included studies met at least 80% of the quality criteria in the MMAT. Major findings include the following: (1) medical and nursing health professionals were unclear on their roles in providing dietary and exercise advice to cancer survivors but agreed they play a key role in referrals to dietitians and exercise professionals; (2) most cancer survivors valued the involvement of their general practitioner when receiving dietary and exercise advice. Conclusion: Although medical and nursing health professionals understand that referrals to allied health professionals form part of their role, there is a lack of clarity regarding their roles to provide dietary and exercise advice to cancer survivors. Future studies should address barriers and facilitators of dietary and exercise advice and referral by medical and nursing health professionals

    A validation study of a smartphone application for functional mobility assessment of the elderly

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    Background: To minimize the reaction time and position judgment error using stopwatch-timed measures, we developed a smartphone application to measure performance in the five-time sit-to-stand (FTSTS) and timed up-and-go (TUG) tests. Objective: This study aimed to validate this smartphone application by comparing its measurement with a laboratory-based reference condition. Methods: Thirty-two healthy elderly people were asked to perform the FTSTS and TUG tests in a randomized sequence. During the tests, their performance was concurrently measured by the smartphone application and a force sensor installed in the backrest of a chair. The intraclass correlation coefficient [ICC(2,1)] and Blande-Altman analysis were used to calculate the measurement consistency and agreement, respectively, between these two methods. Results: The smartphone application demonstrated excellent measurement consistency with the lab-based reference condition for the FTSTS test [ICC(2,1) = 0.988] and TUG test [ICC(2,1) = 0.946]. We observed a positive bias of 0.27 seconds (95% limits of agreement, -1.22 to 1.76 seconds) for the FTSTS test and 0.48 seconds (95% limits of agreement, -1.66 to 2.63 seconds) for the TUG test. Conclusion: We cross-validated the newly developed smartphone application with the laboratory-based reference condition during the examination of FTSTS and TUG test performance in healthy elderly

    A note on the effects of inorganic seed aerosol on the oxidation state of secondary organic aerosol-α-Pinene ozonolysis

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    We compare the oxidation state and molecular composition of α-pinene-derived secondary organic aerosol (SOA) by varying the types and surface areas of inorganic seed aerosol that are used to promote the condensation of SOA-forming vapors. The oxidation state of α-pinene SOA is found to increase with inorganic seed surface area, likely a result of enhanced condensation of low-volatility organic compounds on particles versus deposition on the chamber wall. α-Pinene SOA is more highly oxygenated in the presence of sodium nitrate (SN) seed than ammonium sulfate seed. The relative abundance of semivolatile monomers and low-volatility dimer components that account for more than half of α-pinene SOA mass is not significantly affected by the composition of seed aerosol. Enhanced uptake of highly oxidized small carboxylic acids onto SN seed particles is observed, which could potentially explain the observed higher SOA oxidation state in the presence of SN seed aerosol. Overall, our results demonstrate that a combined effect of seed aerosol composition and surface area leads to an increase in the O:C atomic ratio of α-pinene SOA by as much as a factor of 2

    H0LiCOW XII. Lens mass model of WFI2033-4723 and blind measurement of its time-delay distance and H0H_0

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    We present the lens mass model of the quadruply-imaged gravitationally lensed quasar WFI2033-4723, and perform a blind cosmographical analysis based on this system. Our analysis combines (1) time-delay measurements from 14 years of data obtained by the COSmological MOnitoring of GRAvItational Lenses (COSMOGRAIL) collaboration, (2) high-resolution Hubble Space Telescope\textit{Hubble Space Telescope} imaging, (3) a measurement of the velocity dispersion of the lens galaxy based on ESO-MUSE data, and (4) multi-band, wide-field imaging and spectroscopy characterizing the lens environment. We account for all known sources of systematics, including the influence of nearby perturbers and complex line-of-sight structure, as well as the parametrization of the light and mass profiles of the lensing galaxy. After unblinding, we determine the effective time-delay distance to be 4784248+399 Mpc4784_{-248}^{+399}~\mathrm{Mpc}, an average precision of 6.6%6.6\%. This translates to a Hubble constant H0=71.64.9+3.8 km s1 Mpc1H_{0} = 71.6_{-4.9}^{+3.8}~\mathrm{km~s^{-1}~Mpc^{-1}}, assuming a flat Λ\LambdaCDM cosmology with a uniform prior on Ωm\Omega_\mathrm{m} in the range [0.05, 0.5]. This work is part of the H0H_0 Lenses in COSMOGRAIL's Wellspring (H0LiCOW) collaboration, and the full time-delay cosmography results from a total of six strongly lensed systems are presented in a companion paper (H0LiCOW XIII).Comment: Version accepted by MNRAS. 29 pages including appendix, 17 figures, 6 tables. arXiv admin note: text overlap with arXiv:1607.0140
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