569 research outputs found

    A review of the genus Coccoglypta Pilsbry, 1895 (Gastropoda: Pulmonata: Camaenidae)

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    FIG. 6. — Potential members of the genus Coccoglypta Pilsbry, 1895: A-D, syntype of Coccoglypta arbusticola (Deshayes, 1870) n. comb. (MNHN-IM-2000-34192); E-H, "Bradybaena" chrysomphala (Möllendorff, 1899), SMF 9159 (lectotype); I-L, Coccoglypta cf. leprosula n. comb. (Heude, 1885) from the Guanwushan Forest Farm. Scale bar: 30 mm.Published as part of Páll-Gergely, Barna, Hunyadi, András, Chen, Zhe-Yu & Lyu, Zhi-Tong, 2019, A review of the genus Coccoglypta Pilsbry, 1895 (Gastropoda: Pulmonata: Camaenidae), pp. 595-608 in Zoosystema 41 (29) on page 603, DOI: 10.5252/zoosystema2019v41a29, http://zenodo.org/record/372611

    Efficiency of electrochemical chloride removal from concrete at different environmental temperatures

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    Electrochemical chloride removal (ECR) is an effective and curative method to treat existed reinforced concrete structures about to suffer or already suffering from chloride attack, however, its application is still limited due to its side effect and efficiency, including the velocity and maximum capacity of chloride removal. This paper presents a temperature related numerical transport model to study the effect of temperature on efficiency of electrochemical chloride removal from concrete. Based on Fick’s law and Nernst-Planck equation with Gauss’ Law, temperature effect, chloride binding, multi-species coupling, electrochemical reactions were taken into account in this model. Temperature effect was considered on diffusion coefficient, chloride binding, ions migration capacity as well as electrolyte concentration. The model was validated by the comparison between the calculated results and experimental data. The results indicate that temperature dose have a considerable influence on electrochemical chloride removal and controlling temperature during treatment is a practical method to improve the electrochemical chloride removal when applied current density is not amplified

    Negative longitudinal magnetoresistance in GaAs quantum wells

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    Negative longitudinal magnetoresistances (NLMRs) have been recently observed in a variety of topological materials and often considered to be associated with Weyl fermions that have a defined chirality. Here we report NLMRs in non-Weyl GaAs quantum wells. In the absence of a magnetic field the quantum wells show a transition from semiconducting-like to metallic behaviour with decreasing temperature. We observed pronounced NLMRs up to 9 Tesla at temperatures above the transition and weak NLMRs in low magnetic fields at temperatures close to the transition and below 5 K. The observed NLMRs show various types of magnetic field behaviour resembling those reported in topological materials. We attribute them to microscopic disorder and use a phenomenological three-resistor model to account for their various features. Our results showcase a new contribution of microscopic disorder in the occurrence of novel phenomena. They may stimulate further work on tuning electronic properties via disorder/defect nano-engineering

    A Search for Extraterrestrial Technosignatures in Archival FAST Survey Data Using a New Procedure

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    The "search for extraterrestrial intelligence" (SETI) commensal surveys aim to scan the sky to find possible technosignatures from the extraterrestrial intelligence (ETI). The mitigation of radio frequency interference (RFI) is an important step, especially for the most sensitive Five-hundred-meter Aperture Spherical radio Telescope (FAST), which can detect more weak RFI. In this paper, we propose several new techniques for RFI mitigation, and use our procedure to search for ETI signals from the archival data of FAST's first SETI commensal survey. We detect the persistent narrowband RFI by setting a threshold of the signals' sky separation, and detect the drifting RFI (and potentially other types of RFI) using the Hough transform. We also use the clustering algorithms to remove more RFI and select candidates. The results of our procedure are compared to the earlier work on the same FAST data. We find that our methods, though relatively simpler in computation, remove more RFI (99.9912% compared to 99.9063% in the earlier work), but preserve the simulated ETI signals except those (5.1%) severely affected by the RFI. We also report more interesting candidate signals, about a dozen of which are new candidates that are not previously reported. In addition, we find that the proposed Hough transform method, with suitable parameters, also has the potential to remove the broadband RFI. We conclude that our methods can effectively remove the vast majority of the RFI while preserving and finding the candidate signals that we are interested in.Comment: 14 pages, 10 figures. AJ accepte

    Gobi agriculture: an innovative farming system that increases energy and water use efficiencies. A review

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    International audienceAbstractIn populated regions/countries with fast economic development, such as Africa, China, and India, arable land is rapidly shrinking due to urban construction and other industrial uses for the land. This creates unprecedented challenges to produce enough food to satisfy the increased food demands. Can the millions of desert-like, non-arable hectares be developed for food production? Can the abundantly available solar energy be used for crop production in controlled environments, such as solar-based greenhouses? Here, we review an innovative cultivation system, namely “Gobi agriculture.” We find that the innovative Gobi agriculture system has six unique characteristics: (i) it uses desert-like land resources with solar energy as the only energy source to produce fresh fruit and vegetables year-round, unlike conventional greenhouse production where the energy need is satisfied via burning fossil fuels or electrical consumption; (ii) clusters of individual cultivation units are made using locally available materials such as clay soil for the north walls of the facilities; (iii) land productivity (fresh produce per unit land per year) is 10–27 times higher and crop water use efficiency 20–35 times greater than traditional open-field, irrigated cultivation systems; (iv) crop nutrients are provided mainly via locally-made organic substrates, which reduce synthetic inorganic fertilizer use in crop production; (v) products have a lower environmental footprint than open-field cultivation due to solar energy as the only energy source and high crop yields per unit of input; and (vi) it creates rural employment, which improves the stability of rural communities. While this system has been described as a “Gobi-land miracle” for socioeconomic development, many challenges need to be addressed, such as water constraints, product safety, and ecological implications. We suggest that relevant policies are developed to ensure that the system boosts food production and enhances rural socioeconomics while protecting the fragile ecological environment
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