2,312 research outputs found

    ACT2 Project: Measuring Energy Savings

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    Pacific Gas and Electric Company has initiated a major demonstration project to test the hypothesis that substantial energy efficiency improvements can be achieved in customer facilities at costs competitive with supply. This paper describes the initial pilot site design, focusing on how energy savings will be tracked and measured. The specific objective of the Advanced Customer Technology Test (ACT^2) for Maximum Energy Efficiency project is to provide scientific field test information, for use by PG&E and its customers, on the maximum energy savings possible, at or below projected competitive costs, by using modern high-efficiency end-use technologies in integrated packages acceptable to the customer. The project is a demand side demonstration analogous to a supply side demonstration, where near commercial advanced technologies are field-tested to determine actual economic and technical performance. PG&E has chosen a "Learn by Doing" approach in the development of the project design, technology design methods, and measurement and monitoring techniques. The project planning is being done in parallel to a "pilot demonstration", with the hope that our planning will be responsive to lessons learned in pilot demonstration. A design to maximize energy efficiency at the pilot demonstration site has been selected, and an energy monitoring system is being designed. The paper describes the pilot site design, the proposed monitoring system and the data processing and analysis system which will be used to collect and analyze the data

    Atomic force microscopy-based mechanobiology

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    Mechanobiology emerges at the crossroads of medicine, biology, biophysics and engineering and describes how the responses of proteins, cells, tissues and organs to mechanical cues contribute to development, differentiation, physiology and disease. The grand challenge in mechanobiology is to quantify how biological systems sense, transduce, respond and apply mechanical signals. Over the past three decades, atomic force microscopy (AFM) has emerged as a key platform enabling the simultaneous morphological and mechanical characterization of living biological systems. In this Review, we survey the basic principles, advantages and limitations of the most common AFM modalities used to map the dynamic mechanical properties of complex biological samples to their morphology. We discuss how mechanical properties can be directly linked to function, which has remained a poorly addressed issue. We outline the potential of combining AFM with complementary techniques, including optical microscopy and spectroscopy of mechanosensitive fluorescent constructs, super-resolution microscopy, the patch clamp technique and the use of microstructured and fluidic devices to characterize the 3D distribution of mechanical responses within biological systems and to track their morphology and functional state.Peer ReviewedPostprint (published version

    Lattice Computation of the Nucleon Scalar Quark Contents at the Physical Point

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    We present a QCD calculation of the u, d, and s scalar quark contents of nucleons based on 47 lattice ensembles with Nf=2+1 dynamical sea quarks, 5 lattice spacings down to 0.054 fm, lattice sizes up to 6 fm, and pion masses down to 120 MeV. Using the Feynman-Hellmann theorem, we obtain fNud=0.0405(40)(35) and fNs=0.113(45)(40), which translates into σπN=38(3)(3)  MeV, σsN=105(41)(37)  MeV, and yN=0.20(8)(8) for the sigma terms and the related ratio, where the first errors are statistical and the second errors are systematic. Using isospin relations, we also compute the individual up and down quark contents of the proton and neutron (results in the main text)

    Microbiological, histological, immunological, and toxin response to antibiotic treatment in the mouse model of Mycobacterium ulcerans disease.

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    Mycobacterium ulcerans infection causes a neglected tropical disease known as Buruli ulcer that is now found in poor rural areas of West Africa in numbers that sometimes exceed those reported for another significant mycobacterial disease, leprosy, caused by M. leprae. Unique among mycobacterial diseases, M. ulcerans produces a plasmid-encoded toxin called mycolactone (ML), which is the principal virulence factor and destroys fat cells in subcutaneous tissue. Disease is typically first manifested by the appearance of a nodule that eventually ulcerates and the lesions may continue to spread over limbs or occasionally the trunk. The current standard treatment is 8 weeks of daily rifampin and injections of streptomycin (RS). The treatment kills bacilli and wounds gradually heal. Whether RS treatment actually stops mycolactone production before killing bacilli has been suggested by histopathological analyses of patient lesions. Using a mouse footpad model of M. ulcerans infection where the time of infection and development of lesions can be followed in a controlled manner before and after antibiotic treatment, we have evaluated the progress of infection by assessing bacterial numbers, mycolactone production, the immune response, and lesion histopathology at regular intervals after infection and after antibiotic therapy. We found that RS treatment rapidly reduced gross lesions, bacterial numbers, and ML production as assessed by cytotoxicity assays and mass spectrometric analysis. Histopathological analysis revealed that RS treatment maintained the association of the bacilli with (or within) host cells where they were destroyed whereas lack of treatment resulted in extracellular infection, destruction of host cells, and ultimately lesion ulceration. We propose that RS treatment promotes healing in the host by blocking mycolactone production, which favors the survival of host cells, and by killing M. ulcerans bacilli

    Sigma term and strangeness content of octet baryons

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    By using lattice QCD computations we determine the sigma terms and strangeness content of all octet baryons by means of an application of the Hellmann-Feynman theorem. In addition to polynomial and rational expressions for the quark mass dependence of octet members, we use SU(3) covariant baryon chiral perturbation theory to perform the extrapolation to the physical up and down quark masses. Our N_f=2+1 lattice ensembles include pion masses down to about 190 MeV in large volumes (M_\pi L > 4), and three values of the lattice spacing. Our main results are the nucleon sigma term \sigma_{\pi N} = 39(4)(^{+18}_{-7}) and the strangeness content y_{N} = 0.20(7)(^{+13}_{-17}). Under the assumption of validity of covariant baryon \chi PT in our range of masses one finds y_{N} = 0.276(77)(^{+90}_{-62}).Comment: LaTeX. 15 pages, 5 figures. Text and results corrected according to Erratum [Phys. Rev. D 93, 039905(E) (2016)

    Herschel observations of extra-ordinary sources: Detecting spiral arm clouds by CH absorption lines

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    We have observed CH absorption lines (J=3/2,N=1J=1/2,N=1J=3/2, N=1 \leftarrow J=1/2, N=1) against the continuum source Sgr~B2(M) using the \textit{Herschel}/HIFI instrument. With the high spectral resolution and wide velocity coverage provided by HIFI, 31 CH absorption features with different radial velocities and line widths are detected and identified. The narrower line width and lower column density clouds show `spiral arm' cloud characteristics, while the absorption component with the broadest line width and highest column density corresponds to the gas from the Sgr~B2 envelope. The observations show that each `spiral arm' harbors multiple velocity components, indicating that the clouds are not uniform and that they have internal structure. This line-of-sight through almost the entire Galaxy offers unique possibilities to study the basic chemistry of simple molecules in diffuse clouds, as a variety of different cloud classes are sampled simultaneously. We find that the linear relationship between CH and H2_2 column densities found at lower AVA_V by UV observations does not continue into the range of higher visual extinction. There, the curve flattens, which probably means that CH is depleted in the denser cores of these clouds.Comment: Accepted for publication in A&A, HIFI Special Issu
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