1,833 research outputs found

    A quantitative ecological study of selected nearshore marine plants and animals at the Diablo Canyon power plant site: a pre-operational baseline, 1973-1978

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    Biologists of the California Department of Fish and Game, under contract with the Pacific Gas and Electric Company, conducted surveys or intertidal and subtidal plants and animals 1n the vicinity of the Diablo Canyon Nuclear Power Plant for the summer of 1973 through 1978. Abundances of the dominant plants and animals were obtained at random as well as permanent stations in Diablo Cove as well as nearby control areas. A total of 643 permanent and random stations were surveyed, 262 in the intertidal and 381 in the subtidal. Natural as well as man-caused occurrences have resulted in several significant changes in plant and animal abundance in the study areas; these include the arrival of the southern front or the sea otter population in Diablo Cove in 1974; a strong red tide bloom in the fall of 1974; and the release of copper ions from the power plant condenser tubes into Diablo Cove during the summer of 1974. Our intertidal and subtidal random station data have shown a strong decline in giant red sea urchin, Strongylocentrotus franciscanus, densities and the surface canopy kelp, Nereocystis/leutkeana, and a corresponding increase in the subcanopy kelps, Pterygophora and Laminaria. Seasonal patterns of abundance of foliose red algae at random intertidal stations occurred at all study areas. Several species intertidal and subtidal invertebrates showed increasing or decreasing trends in levels of abundance during the five year study period covered by the report. Some of these changes in abundance may be related to the natural man-caused impacts mentioned above. (Document has 728 pages

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    Filamentary Accretion Flows in the Embedded Serpens South Protocluster

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    One puzzle in understanding how stars form in clusters is the source of mass -- is all of the mass in place before the first stars are born, or is there an extended period when the cluster accretes material which can continuously fuel the star formation process? We use a multi-line spectral survey of the southern filament associated with the Serpens South embedded cluster-forming region in order to determine if mass is accreting from the filament onto the cluster, and whether the accretion rate is significant. Our analysis suggests that material is flowing along the filament's long axis at a rate of ~30Msol/Myr (inferred from the N2H+ velocity gradient along the filament), and radially contracting onto the filament at ~130Msol/Myr (inferred from HNC self-absorption). These accretion rates are sufficient to supply mass to the central cluster at a similar rate to the current star formation rate in the cluster. Filamentary accretion flows may therefore be very important in the ongoing evolution of this cluster.Comment: 19 pages, 8 figures, 2 tables; accepted for publication in Ap

    Network device interface for digitally interfacing data channels to a controller via a network

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    A communications system and method are provided for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is converted into digital signals and transmitted to the controller. Network device interfaces associated with different data channels can coordinate communications with the other interfaces based on either a transition in a command message sent by the bus controller or a synchronous clock signal

    Network device interface for digitally interfacing data channels to a controller via a network

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    The present invention provides a network device interface and method for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is then converted by the network device interface into digital signals and transmitted back to the controller. In one advantageous embodiment, the network device interface uses a specialized protocol for communicating across the network bus that uses a low-level instruction set and has low overhead for data communication

    Macrostates vs. Microstates in the Classical Simulation of Critical Phenomena in Quench Dynamics of 1D Ising Models

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    We study the tractability of classically simulating critical phenomena in the quench dynamics of one-dimensional transverse field Ising models (TFIMs) using highly truncated matrix product states (MPS). We focus on two paradigmatic examples: a dynamical quantum phase transition (DQPT) that occurs in nonintegrable long-range TFIMs, and the infinite-time correlation length of the integrable nearest-neighbor TFIM when quenched to the critical point. For the DQPT, we show that the order parameters can be efficiently simulated with surprisingly heavy truncation of the MPS bond dimension. This can be used to reliably extract critical properties of the phase transition, including critical exponents, even when the full many-body state is not simulated with high fidelity. The long-time correlation length near the critical point is more sensitive to the full many-body state fidelity, and generally requires a large bond dimension MPS. Nonetheless, we find that this can still be efficiently simulated with strongly truncated MPS because it can be extracted from the short-time behavior of the dynamics where entanglement is low. Our results demonstrate that while accurate calculation of the full many-body state (microstate) is typically intractable due to the volume-law growth of entanglement, a precise specification of an exact microstate may not be required when simulating phases of matter of many-body systems (macrostates). We also study the tractability of simulation using truncated MPS based on quantum chaos and equilibration in the models. We find a counterintuitive inverse relationship, whereby local expectation values are most easily approximated for chaotic systems whose exact many-body state is most intractable.Comment: 6 sections, 4 appendices, 19 figure

    ELF3 controls thermoresponsive growth in Arabidopsis

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    Plant development is highly responsive to ambient temperature, and this trait has been linked to the ability of plants to adapt to climate change [1]. The mechanisms by which natural populations modulate their thermoresponsiveness are not known [2]. To address this, we surveyed Arabidopsis accessions for variation in thermal responsiveness of elongation growth and mapped the corresponding loci. We find that the transcriptional regulator EARLY FLOWERING3 (ELF3) controls elongation growth in response to temperature. Through a combination of modeling and experiments, we show that high temperature relieves the gating of growth at night, highlighting the importance of temperature-dependent repressors of growth. ELF3 gating of transcriptional targets responds rapidly and reversibly to changes in temperature. We show that the binding of ELF3 to target promoters is temperature dependent, suggesting a mechanism where temperature directly controls ELF3 activity
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