4,043 research outputs found

    Source of water in basins off southern California

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    Water temperature and salinity measurements from most of the 14 basins off southern California, when compared with older data, show no detectable changes. The water in each basin is nearly isothermal and isohaline from the bottom to near the sill depth...

    Wave patterns off southern California

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    Mapping of wave trains during four flights over the ocean off southern California showed the consistent presence of a high 10-second swell from the westnorthwest, of one or two low 3- to 5-second swells from other westerly directions, and of local wind waves; occasionally a low 13-second swell from the west and southwest was also present. Islands reduce the height of swells but produce little discernable crossswell in their lee...

    Oceanography on a Postage Stamp

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    Many postage stamps have designs that illustrate various aspects of oceanography. A representative selection of them reveals an international interest in the oceans

    Water tables in marine beaches

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    Beach slopes, sand movements, and sand composition have been studied by a number of organizations and individuals, but the interstitial water and the possible interrelations between beach characteristics and changing water levels within the beach seem to have received little attention...

    Cultivating inclusive instructional and research environments in ecology and evolutionary science

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    As we strive to lift up a diversity of voices in science, it is important for ecologists, evolutionary scientists, and educators to foster inclusive environments in their research and teaching. Academics in science often lack exposure to research on best practices in diversity, equity, and inclusion and may not know where to start to make scientific environments more welcoming and inclusive. We propose that by approaching research and teaching with empathy, flexibility, and a growth mind-set, scientists can be more supportive and inclusive of their colleagues and students. This paper provides guidance, explores strategies, and directs scientists to resources to better cultivate an inclusive environment in three common settings: the classroom, the research laboratory, and the field. As ecologists and evolutionary scientists, we have an opportunity to adapt our teaching and research practices in order to foster an inclusive educational ecosystem for students and colleagues alike

    Distinct nature of static and dynamic magnetic stripes in cuprate superconductors

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    We present detailed neutron scattering studies of the static and dynamic stripes in an optimally doped high-temperature superconductor, La2_2CuO4+y_{4+y}. We find that the dynamic stripes do not disperse towards the static stripes in the limit of vanishing energy transfer. We conclude that the dynamic stripes observed in neutron scattering experiments are not the Goldstone modes associated with the broken symmetry of the simultaneously observed static stripes, but rather that the signals originate from different domains in the sample. These domains may be related by structural twinning, or may be entirely different phases, where the static stripes in one phase are pinned versions of the dynamic stripes in the other. Our results explain earlier observations of unusual dispersions in underdoped La2x_{2-x}Srx_xCuO4_{4} (x=0.07x=0.07) and La2x_{2-x}Bax_xCuO4_{4} (x=0.095x=0.095). Our findings are relevant for all compounds exhibiting magnetic stripes, and may thus be a vital part in unveiling the nature of high temperature superconductivity

    Band-Insulator-Metal-Mott-Insulator transition in the half--filled ttt-t^{\prime} ionic-Hubbard chain

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    We investigate the ground state phase diagram of the half-filled ttt-t^{\prime} repulsive Hubbard model in the presence of a staggered ionic potential Δ\Delta, using the continuum-limit bosonization approach. We find, that with increasing on-site-repulsion UU, depending on the value of the next-nearest-hopping amplitude tt^{\prime}, the model shows three different versions of the ground state phase diagram. For t<tt^{\prime} < t^{\prime}_{\ast}, the ground state phase diagram consists of the following three insulating phases: Band-Insulator at U<UcU<U_{c}, Ferroelectric Insulator at UcUcU_{c} U_{c}. For t>tct^{\prime} > t^{\prime}_{c} there is only one transition from a spin gapped metallic phase at UUcU U_{c}. Finally, for intermediate values of the next-nearest-hopping amplitude t<t<tct^{\prime}_{\ast} < t^{\prime} < t^{\prime}_{c} we find that with increasing on-site repulsion, at Uc1U_{c1} the model undergoes a second-order commensurate-incommensurate type transition from a band insulator into a metallic state and at larger Uc2U_{c2} there is a Kosterlitz-Thouless type transition from a metal into a ferroelectric insulator.Comment: 9 pages 3 figure

    Zeeman smearing of the Coulomb blockade

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    Charge fluctuations of a large quantum dot coupled to a two-dimensional lead via a single-mode good Quantum Point Contact (QPC) and capacitively coupled to a back-gate, are investigated in the presence of a parallel magnetic field. The Zeeman term induces an asymmetry between transmission probabilities for the spin-up and spin-down channels at the QPC, producing noticeable effects on the quantization of the grain charge already at low magnetic fields. Performing a quantitative analysis, I show that the capacitance between the gate and the lead exhibits - instead of a logarithmic singularity - a reduced peak as a function of gate voltage. Experimental applicability is discussed.Comment: 5 pages, 3 figures (Final version

    Luther-Emery Stripes, RVB Spin Liquid Background and High Tc Superconductivity

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    The stripe phase in high Tc cuprates is modeled as a single stripe coupled to the RVB spin liquid background by the single particle hopping process. In normal state, the strong pairing correlation inherent in RVB state is thus transfered into the Luttinger stripe and drives it toward spin-gap formation described by Luther-Emery Model. The establishment of global phase coherence in superconducting state contributes to a more relevant coupling to Luther-Emery Stripe and leads to gap opening in both spin and charge sectors. Physical consequences of the present picture are discussed, and emphasis is put on the unification of different energy scales relevant to cuprates, and good agreement is found with the available experimental results, especially in ARPES.Comment: 4 pages, RevTe
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