364 research outputs found

    Análisis de los manuales de alemán en las universidades chinas: Contenido medioambiental y perspectivas ecológicas

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    German is offered to students as one of the leading foreign languages in Chinese universities, and German language textbooks are an important resource to influence these students’ environmental awareness. Taking transitivity as a theoretical framework, the present research was conducted to explore the transitivity features and ecological view of the environmental content in German language textbooks used in Chinese universities. The results show that transitivity patterns were significantly unbalanced in the environmental content, and an eco-beneficial view dominated to actively encourage students to protect nature. However, the political and cultural values underlying humanity’s destruction of the natural environment were not much touched upon. Corresponding suggestions are made for textbook compilers and classroom teachers. FUNDING INFORMATION. This research was supported by a Grant from the Foreign Language Education and Teaching Reform of Lanzhou Jiaotong University (JGZ202337). We would like to express our thanks to the anonymous reviewers and the editors for their constructive suggestions on this research.El alemán es una lengua extranjera clave que estudian los universitarios chinos, y los manuales de alemán se han convertido en un importante recurso que influye en la conciencia medioambiental de estos alumnos. Este estudio utiliza la transitividad como marco teórico para explorar las características de transitividad y las perspectivas ecológicas del contenido medioambiental de los manuales de alemán de las universidades chinas. Los resultados muestran que el uso del modelo de transitividad para los contenidos medioambientales es muy desigual; predominan las perspectivas ecológicamente beneficiosas para animar a los alumnos a proteger la naturaleza. Sin embargo, no se abordan suficientemente los valores políticos y culturales que subyacen a la destrucción de la naturaleza por los seres humanos. Este documento ofrece sugerencias al respecto para los autores de manuales y los profesores de la asignatura

    A Survey on the Higher Education “Three Spirits” Construction in Sichuan Province, PRC

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    Under the guidance of “the Scientific Outlook on Development”, the Sichuan universities and colleges have rethought the present lazy and separate situation of the “Three Spirits”. Based on analyzing the relationship of the “Three Spirits”, they have taken such measures as constructing learning group and cultivating educational tradition etc, and established the mechanism of “educational guidance” and “cultural edification” to promote the virtuous change of the “Three Spirits”construction, it thus has important practical value

    Giant uterine artery pseudoaneurysm after a missed miscarriage termination in a cesarean scar pregnancy

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    BACKGROUND: Uterine artery pseudoaneurysms are dangerous and can lead to severe hemorrhage. We report an uncommon cause of a giant pseudoaneurysm in a missed miscarriage in a woman with a cesarean scar pregnancy. CASE PRESENTATION: The patient was a 25-year-old Chinese woman with a missed miscarriage in a cesarean scar pregnancy. Curettage was performed under ultrasound monitoring. A uterine artery pseudoaneurysm measuring 71 × 44 × 39 mm was detected the next day by Doppler ultrasonography. While waiting for admittance to an advanced institution to undergo embolization treatment, the pseudoaneurysm ruptured spontaneously. The subsequent severe hemorrhage necessitated hysterectomy. CONCLUSION: A delay in diagnosis of uterine artery pseudoaneurysms may result from a long period between the curettage and follow-up examination. Ultrasound and Doppler ultrasonography should be performed repeatedly at short intervals to rule out them, especially in cesarean scar pregnancies. For a giant uterine artery pseudoaneurysm, interventional embolization might be the first treatment choice. If time allows, intra-operative ligation of the feeding vessels should be attempted before any decision to perform a hysterectomy is made. However, hysterectomy remains a possibility when severe bleeding occurs

    Three-dimensionality of the bulk electronic structure in WTe2

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    We use temperature- and field-dependent resistivity measurements [Shubnikov--de Haas (SdH) quantum oscillations] and ultrahigh resolution, tunable, vacuum ultraviolet (VUV) laser-based angle-resolved photoemission spectroscopy (ARPES) to study the three-dimensionality (3D) of the bulk electronic structure in WTe2, a type-II Weyl semimetal. The bulk Fermi surface (FS) consists of two pairs of electron pockets and two pairs of hole pockets along the X-Gamma-X direction as detected by using an incident photon energy of 6.7 eV, which is consistent with the previously reported data. However, if using an incident photon energy of 6.36 eV, another pair of tiny electron pockets is detected on both sides of the Gamma point, which is in agreement with the small quantum oscillation frequency peak observed in the magnetoresistance. Therefore, the bulk, 3D FS consists of three pairs of electron pockets and two pairs of hole pockets in total. With the ability of fine tuning the incident photon energy, we demonstrate the strong three-dimensionality of the bulk electronic structure in WTe2. The combination of resistivity and ARPES measurements reveal the complete, and consistent, picture of the bulk electronic structure of this material.Comment: 6 pages, 3 figure

    Observation of Fermi Arcs in Type-II Weyl Semimetal Candidate WTe2

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    We use ultrahigh resolution, tunable, vacuum ultraviolet laser angle-resolved photoemission spectroscopy (ARPES) to study the electronic properties of WTe2_2, a material that was predicted to be a type-II Weyl semimetal. The Weyl fermion states in WTe2 were proposed to emerge at the crossing points of electron and hole pockets; and Fermi arcs connecting electron and hole pockets would be visible in the spectral function on (001) surface. Here we report the observation of such Fermi arcs in WTe2 confirming the theoretical predictions. This provides strong evidence for type-II Weyl semimetallic states in WTe2.Comment: 5 pages, 4 figure

    Electronic structure of RSb (R = Y, Ce, Gd, Dy, Ho, Tm, Lu) studied by angle-resolved photoemission spectroscopy

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    We use high resolution angle-resolved photoemission spectroscopy (ARPES) and electronic structure calculations to study the electronic properties of rare-earth monoantimonides RSb (R = Y, Ce, Gd, Dy, Ho, Tm, Lu). The experimentally measured Fermi surface (FS) of RSb consists of at least two concentric hole pockets at the Γ\Gamma point and two intersecting electron pockets at the XX point. These data agree relatively well with the electronic structure calculations. Detailed photon energy dependence measurements using both synchrotron and laser ARPES systems indicate that there is at least one Fermi surface sheet with strong three-dimensionality centered at the Γ\Gamma point. Due to the "lanthanide contraction", the unit cell of different rare-earth monoantimonides shrinks when changing rare-earth ion from CeSb to LuSb. This results in the differences in the chemical potentials in these compounds, which is demonstrated by both ARPES measurements and electronic structure calculations. Interestingly, in CeSb, the intersecting electron pockets at the XX point seem to be touching the valence bands, forming a four-fold degenerate Dirac-like feature. On the other hand, the remaining rare-earth monoantimonides show significant gaps between the upper and lower bands at the XX point. Furthermore, similar to the previously reported results of LaBi, a Dirac-like structure was observed at the Γ\Gamma point in YSb, CeSb, and GdSb, compounds showing relatively high magnetoresistance. This Dirac-like structure may contribute to the unusually large magnetoresistance in these compounds.Comment: 8 figure

    Using molecular dynamics simulations as an aid in the prediction of domain swapping of computationally designed protein variants

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    In standard implementations of computational protein design, a positive-design approach is used to predict sequences that will be stable on a given backbone structure. Possible competing states are typically not considered, primarily because appropriate structural models are not available. One potential competing state, the domain-swapped dimer, is especially compelling because it is often nearly identical to its monomeric counterpart, differing by just a few mutations in a hinge region. Molecular dynamics (MD) simulations provide a computational method to sample different conformational states of a structure. Here, we tested whether MD simulations could be used as a post-design screening tool to identify sequence mutations leading to domain-swapped dimers. We hypothesized that a successful computationally-designed sequence would have backbone structure and dynamics characteristics similar to that of the input structure, and that in contrast, domain-swapped dimers would exhibit increased backbone flexibility and/or altered structure in the hinge-loop region to accommodate the large conformational change required for domain swapping. While attempting to engineer a homodimer from a 51 amino acid fragment of the monomeric protein engrailed homeodomain (ENH), we had instead generated a domain-swapped dimer (ENH_DsD). MD simulations on these proteins showed increased MD simulation derived B factors in the hinge loop of the ENH_DsD domain-swapped dimer relative to monomeric ENH. Two point mutants of ENH_DsD designed to recover the monomeric fold were then tested with an MD simulation protocol. The MD simulations suggested that one of these mutants would adopt the target monomeric structure, which was subsequently confirmed by X-ray crystallography

    Computational Design of the β-Sheet Surface of a Red Fluorescent Protein Allows Control of Protein Oligomerization

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    Computational design has been used with mixed success for the design of protein surfaces, with directed evolution heretofore providing better practical solutions than explicit design. Directed evolution, however, requires a tractable high-throughput screen because the random nature of mutation does not enrich for desired traits. Here we demonstrate the successful design of the β-sheet surface of a red fluorescent protein (RFP), enabling control over its oligomerization. To isolate the problem of surface design, we created a hybrid RFP from DsRed and mCherry with a stabilized protein core that allows for monomerization without loss of fluorescence. We designed an explicit library for which 93 of 96 (97%) of the protein variants are soluble, stably fluorescent, and monomeric. RFPs are heavily used in biology, but are natively tetrameric, and creating RFP monomers has proven extremely difficult. We show that surface design and core engineering are separate problems in RFP development and that the next generation of RFP markers will depend on improved methods for core design

    R3^3-Net: A Deep Network for Multi-oriented Vehicle Detection in Aerial Images and Videos

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    Vehicle detection is a significant and challenging task in aerial remote sensing applications. Most existing methods detect vehicles with regular rectangle boxes and fail to offer the orientation of vehicles. However, the orientation information is crucial for several practical applications, such as the trajectory and motion estimation of vehicles. In this paper, we propose a novel deep network, called rotatable region-based residual network (R3^3-Net), to detect multi-oriented vehicles in aerial images and videos. More specially, R3^3-Net is utilized to generate rotatable rectangular target boxes in a half coordinate system. First, we use a rotatable region proposal network (R-RPN) to generate rotatable region of interests (R-RoIs) from feature maps produced by a deep convolutional neural network. Here, a proposed batch averaging rotatable anchor (BAR anchor) strategy is applied to initialize the shape of vehicle candidates. Next, we propose a rotatable detection network (R-DN) for the final classification and regression of the R-RoIs. In R-DN, a novel rotatable position sensitive pooling (R-PS pooling) is designed to keep the position and orientation information simultaneously while downsampling the feature maps of R-RoIs. In our model, R-RPN and R-DN can be trained jointly. We test our network on two open vehicle detection image datasets, namely DLR 3K Munich Dataset and VEDAI Dataset, demonstrating the high precision and robustness of our method. In addition, further experiments on aerial videos show the good generalization capability of the proposed method and its potential for vehicle tracking in aerial videos. The demo video is available at https://youtu.be/xCYD-tYudN0
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