451 research outputs found

    Frequency shifts in noble-gas magnetometers

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    Polarized nuclei are a powerful tool in nuclear spin studies and in searches for beyond-the-standard model physics. Noble-gas comagnetometer systems, which compare two nuclear species, have thus far been limited by anomalous frequency variations of unknown origin. We studied the self-interactions in a 3^3He-129^{129}Xe system by independently addressing, controlling and measuring the influence of each component of the nuclear spin polarization. Our results directly rule out prior explanations of the shifts, and demonstrate experimentally that they can be explained by species dependent self-interactions. We also report the first gas phase frequency shift induced by 129^{129}Xe on 3^3He.Comment: v.

    A case study for a multitemporal segmentation approach in optical remote sensing images.

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    Continuous observations from remote sensors provide high temporal and spatial resolution imagery, and better remote sensing image segmentation techniques are mandatory for efficient analysis. Among them, one of the most applied segmentation techniques is the region growing algorithm. Within this context, this paper describes a study case for a multitemporal segmentation that adapts the traditional region growing technique. Our method aims to detect homogeneous regions in space and time observing a sequence of optical remote sensing images. Tests were conducted by considering the Dynamic Time Warping distance as the homogeneity criterion to grow regions. A case study on high temporal resolution for sequences of Landsat-8 vegetation indices products provided satisfactory outputs.GEOProcessing 2018

    List-method directed forgetting: Do critical findings generalize from short to long retention intervals?

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    People can purposefully forget information that has become irrelevant, as is demonstrated in list-method directed forgetting (LMDF). In this task, participants are cued to intentionally forget an already studied list (list 1) before encoding a second list (list 2); this induces forgetting of the first-list items. Most research on LMDF has been conducted with short retention intervals, but very recent studies indicate that such directed forgetting can be lasting. We examined in two experiments whether core findings in the LMDF literature generalize from short to long retention intervals. The focus of Experiment 1 was on the previous finding that, with short retention interval, list-2 encoding is necessary for list-1 forgetting to arise. Experiment 1 replicated the finding after a short delay of 3 min between study and test and extended it to a longer delay of 20 min. The focus of Experiment 1 was on the absence of list-1 forgetting in item recognition, previously observed after short retention interval. Experiment 1 replicated the finding after a short delay of 3 min between study and test and extended it to longer delays of 20 min and 24 h. Implications of the results for theoretical explanations of LMDF are discussed

    A next generation measurement of the electric dipole moment of the neutron at the FRM II

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    In this paper we discuss theoretical motivations and the status of experimental searches to find time-reversal symmetry-violating electric dipole moments (EDM). Emphasis is given to a next generation search for the EDM of the neutron, which is currently being set up at the FRM II neutron source in Garching, with an ultimate sensitivity goal of 5 × 10−28 cm (3σ). The layout of the apparatus allows for the detailed investigation of systematic effects by combining various means of magnetic field control and polarized UCN optics. All major components of the installations are portable and can be installed at the strongest available UCN beam
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