1,542 research outputs found

    Between Democracy and Technocracy: : Ecology as Multidisciplinary Science in the Transpacific Cold War

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    This paper investigates the circulation of ecological knowledge and practices between North America and Southeast Asia via ecologists’ involvement in the politics of science during the Transpacific Cold War. Historians have documented how American scientists in the early Cold War (1945–1965) faced the contradiction between their apparent ‘freedom’ to conduct research compared to scientists in socialist countries, on the one hand, and the imperative to depoliticise the connection between their research and the military-industrial complex, on the other hand. Historians have also shown how the environmental, civil rights and antiwar movements severely challenged this apolitical science by the late 1960s. The popularisation of ecology and its convergence with environmental politics after the 1970s are often viewed as part of this trend of repoliticising science in North America

    Development of Database of Cyclic Soil Properties from 94 Tests on 47 Soils

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    Cyclic properties of 47 soils were tested in several investigations between 1994 and 2004 in the standard Norwegian Geotechnical Institute (NGI) direct simple shear (DSS) device and an NGI-type dual-specimen DSS (DSDSS) device for small strain testing. In each investigation many cycles of different amplitude, c, and frequency, f, were applied at different levels of vertical stress, v, and overconsolidation ratio, OCR. In DSDSS device many consecutive series of different small c=0.0003-0.01% were applied on the same specimens without changing their structure, because at such small c cyclic shearing is nondestructive. Consequently, the vast amounts of small-strain data were generated. This necessitated the development of new approach to data processing and analysis. New procedure for reading, checking, organizing, combining, comparing and analyzing the vast arrays of cyclic test data has been developed and structured into a database that has the cyclic loop as its elementary unit. Each cyclic loop in the database is characterized by the soils’ plasticity index, moisture content, void ratio, degree of saturation, v, OCR, c, f, secant shear modulus, damping ratio, and the shape of cyclic straining. Using the database very large number of cyclic loops can be compared to instantly obtain graphical presentation of different behavioral trends. The structure of the database and its application is summarized

    On the origin of non-monotonic doping dependence of the in-plane resistivity anisotropy in Ba(Fe1−xTx_{1-x}T_x)2_2As2_2, TT = Co, Ni and Cu

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    The in-plane resistivity anisotropy has been measured for detwinned single crystals of Ba(Fe1−x_{1-x}Nix_x)2_2As2_2 and Ba(Fe1−x_{1-x}Cux_x)2_2As2_2. The data reveal a non-monotonic doping dependence, similar to previous observations for Ba(Fe1−x_{1-x}Cox_x)2_2As2_2. Magnetotransport measurements of the parent compound reveal a non-linear Hall coefficient and a strong linear term in the transverse magnetoresistance. Both effects are rapidly suppressed with chemical substitution over a similar compositional range as the onset of the large in-plane resistivity anisotropy. It is suggested that the relatively small in-plane anisotropy of the parent compound in the spin density wave state is due to the presence of an isotropic, high mobility pocket of reconstructed Fermi surface. Progressive suppression of the contribution to the conductivity arising from this isotropic pocket with chemical substitution eventually reveals the underlying in-plane anisotropy associated with the remaining FS pockets.Comment: 12 pages, 9 figure

    In-Flight Transmission of SARS-CoV-2.

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    Four persons with severe acute respiratory syndrome coronavirus 2 infection had traveled on the same flight from Boston, Massachusetts, USA, to Hong Kong, China. Their virus genetic sequences are identical, unique, and belong to a clade not previously identified in Hong Kong, which strongly suggests that the virus can be transmitted during air travel

    Self-locked optical parametric oscillation in a CMOS compatible microring resonator: a route to robust optical frequency comb generation on a chip

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    We report a novel geometry for OPOs based on nonlinear microcavity resonators. This approach relies on a self-locked scheme that enables OPO emission without the need for thermal locking of the pump laser to the microcavity resonance. By exploiting a CMOS-compatible microring resonator, we achieve oscillation featured by a complete absence of “shutting down”, i.e. the self-terminating behavior that is a very common and detrimental occurrence in externally pumped OPOs. Further, our scheme consistently produces very wide bandwidth (>300nm, limited by our experimental set-up) combs that oscillate at a spacing equal to the FSR of the micro cavity resonance

    Precision Feshbach spectroscopy of ultracold Cs-2

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    We have observed and located more than 60 magnetic field-induced Feshbach resonances in ultracold collisions of ground-state Cs-133 atoms. Multiple extremely weak Feshbach resonances associated with g-wave molecular states are detected through variations in the radiative collision cross sections. The Feshbach spectroscopy allows us to determine the interactions between ultracold cesium atoms and the molecular energy structure near the dissociation continuum with unprecedented precision. Our work not only represents a very successful collaboration of experimental and theoretical efforts, but also provides essential information for cesium Bose-Einstein condensation, Cs-2 molecules, and atomic clock experiments
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