28 research outputs found

    Exploring the Benefits of Small Catchments on Rural Spatial Governance in Wuling Mountain Area, China

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    China is facing an important period of rural governance innovation and restructuring of territorial spatial patterns. This paper selects catchments as the most closely related spatial units for rural industrial development and rural settlement activities, profoundly revealing the characteristics of transformational development and spatial governance in mountainous areas. To date, extensive literature in this area has produced a broad multidisciplinary consensus on catchment water and soil conservation and rural industry development; however, the interactive mechanism of ecological, social, and economic networks, and the characteristics behind small catchments which benefit from spatial governance, have never been analyzed and are relatively new to the sphere of rural governance. Our research argues the relative importance of multi-scale catchment units compared with traditional administrative village units in enhancing the organizational benefits of rural revitalization in terms of workforce, resources, and capital, using the case study of a catchment in the Wuling mountainous area. Our study presents a framework to explore the multi-dimensional governance experience of a small catchment in the Wuling mountainous area and proposes to integrate the resource endowment advantages of small catchments into rural industries development and transform the economic and social benefits contained in the ecological environment into multi-scale spatial benefits among farmers, villages, and the regional rural area. However, not all cases provide positive evidence. The overall development of a catchment is confronted with complex constraints, which are mainly related to the development stage and local historical and geographical factors. Furthermore, affected by the top-down “project-system” in the “poverty era”, the logic of “betting on the strong” and the single-centered logic of resource allocation at the grassroots level exacerbated the fragmentation of the mountainous area. Generally speaking, the catchment perspective promotes regional linkage development and multi-center governance modes and triggers multidisciplinary theoretical thinking to some extent. The catchment’s overall development helps play to the comparative advantage of mountainous areas and promotes endogenous sustainable development to a certain degree. However, the promotion of catchment governance in poverty-stricken mountainous areas is faced with a lack of financial foundation and needs support in order to break through the national system and local social constraints

    Absolute co-supplement and absolute co-coclosed modules

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    A module M is called an absolute co-coclosed (absolute co-supplement) module if whenever M ≅ T/X the submodule X of T is a coclosed (supplement) submodule of T. Rings for which all modules are absolute co-coclosed (absolute co-supplement) are precisely determined. We also investigate the rings whose (finitely generated) absolute co-supplement modules are projective. We show that a commutative domain R is a Dedekind domain if and only if every submodule of an absolute co-supplement R-module is absolute co-supplement. We also prove that the class Coclosed of all short exact sequences 0→A→B→C→0 such that A is a coclosed submodule of B is a proper class and every extension of an absolute co-coclosed module by an absolute co-coclosed module is absolute co-coclosed.Scientific and Technical Research Council of Turke

    Broadband Anisotropy in Terahertz Metamaterial With Single-Layer Gap Ring Array

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    To convert the polarization of terahertz waves pumped by a femtosecond laser in a terahertz time domain system, a broadband anisotropic metamaterial is proposed. The metamaterial is constructed with a single-layer gapped metallic ring array, which supports different resonant modes in orthogonal directions. With the aid of simulations and measurements, the anisotropy of the terahertz transmission is demonstrated and discussed. The experimental results of THz transmission in the metamaterial indicate that the anisotropic band is as wide as 0.56 THz, which accords well with our theoretical prediction

    Graphene Terahertz Amplitude Modulation Enhanced by Square Ring Resonant Structure

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    Corneal biomechanical properties in healthy children measured by corneal visualization scheimpflug technology

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    Abstract Background The aim of this study was to evaluate corneal biomechanical properties in a population of healthy children in China using corneal visualization Scheimpflug technology (CST). Methods All children underwent complete bi-ocular examinations. CST provided intraocular pressure (IOP) and corneal biomechanical parameters, including time, velocity, length and deformation amplitude at first applanation (A1T, A1V, A1L, A1DA), at second applanation (A2T, A2V, A2L, A2DA), highest concavity time (HCT), maximum deformation amplitude (MDA), peak distance (PD), and radius of curvature (RoC). Pearson correlation analysis was used to assess the impacts of demographic factors, central corneal thickness (CCT), spherical equivalent (SE), and IOP on corneal biomechanics. Results One hundred eight subjects (32 girls and 76 boys) with the mean age of 10.80 ± 4.13 years (range 4 to18 years) were included in the final analyses. The right and left eyes were highly symmetrical in SE (p = 0.082), IOP (p = 0.235), or CCT (p = 0.210). Mean A1T of the right eyes was 7.424 ± 0.340 ms; the left eyes 7.451 ± 0.365 ms. MDA was 0.993 ± 0.102 mm in the right eyes and 0.982 ± 0.100 mm in the left eyes. Mean HCT of the right eyes was 16.675 ± 0.502 ms; the left eyes 16.735 ± 0.555 ms. All CST parameters of both eye were remarkably symmetrical with the exception of A2L (p = 0.006), A1DA (p = 0.025). The majority of CST parameters of both eyes were significantly correlated with CCT and IOP (p < 0.05). However, age, SE, and sex exert little influence on the CST measurements. Conclusions This study found interocular symmetry in corneal biomechanics in healthy children eyes. Several CST biomechanical parameters in children are modified by CCT and IOP

    Deep Electrical Modulation of Terahertz Wave Based on Hybrid Metamaterial-Dielectric-Graphene Structure

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    A terahertz modulation structure based on hybrid metamaterial and graphene is proposed and demonstrated in this work. The metamaterial with a square slit ring array excites terahertz resonance in the slits and enhances the interaction between the terahertz wave and graphene. The graphene layer acting as the active material is tuned by the applied electrical field. With the separation by a dielectric layer between the graphene and the metallic structure, the resonant frequency and transmitted energy are both modulated by the graphene. Experimental result indicates that the modulation depth of the terahertz transmitted amplitude is 65.1% when the applied modulation voltage is tuned 5 V

    Low Prognostic Nutritional Index (PNI) Predicts Unfavorable Distant Metastasis-Free Survival in Nasopharyngeal Carcinoma: A Propensity Score-Matched Analysis

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    <div><p>Background</p><p>Poor nutritional status is associated with progression and advanced disease in patients with cancer. The prognostic nutritional index (PNI) may represent a simple method of assessing host immunonutritional status. This study was designed to investigate the prognostic value of the PNI for distant metastasis-free survival (DMFS) in patients with nasopharyngeal carcinoma (NPC).</p><p>Methods</p><p>A training cohort of 1,168 patients with non-metastatic NPC from two institutions was retrospectively analyzed. The optimal PNI cutoff value for DMFS was identified using the online tool “Cutoff Finder”. DMFS was analyzed using stratified and adjusted analysis. Propensity score-matched analysis was performed to balance baseline characteristics between the high and low PNI groups. Subsequently, the prognostic value of the PNI for DMFS was validated in an external validation cohort of 756 patients with NPC. The area under the receiver operating characteristics curve (AUC) was calculated to compare the discriminatory ability of different prognostic scores.</p><p>Results</p><p>The optimal PNI cutoff value was determined to be 51. Low PNI was significantly associated with poorer DMFS than high PNI in univariate analysis (P<0.001) as well as multivariate analysis (P<0.001) before propensity score matching. In subgroup analyses, PNI could also stratify different risks of distant metastases. Propensity score-matched analyses confirmed the prognostic value of PNI, excluding other interpretations and selection bias. In the external validation cohort, patients with high PNI also had significantly lower risk of distant metastases than those with low PNI (Hazards Ratios, 0.487; P<0.001). The PNI consistently showed a higher AUC value at 1-year (0.780), 3-year (0.793) and 5-year (0.812) in comparison with other prognostic scores.</p><p>Conclusion</p><p>PNI, an inexpensive and easily assessable inflammatory index, could aid clinicians in developing individualized treatment and follow-up strategies for patients with non-metastatic NPC.</p></div

    Efficient CO2 reduction MOFs derivatives transformation mechanism revealed by in-situ liquid phase TEM

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    Materials derived from MOFs have great potentials in energy conversion. However, the nanoscale transformation processes of MOFs derivatives remain unknown. Herein, by using in-situ liquid phase TEM, we directly visualize the MOFs etching processes. For the first time, unexpected nanobubble stability controlled transformation mechanism of ZIF-67 to porous or layered cobalt transition metal hydroxide (Co-TMH) is identified. Voids in MOFs migrate and merge to form nanobubbles due to structural collapse. Under slow diffusion conditions, nanobubbles move slowly and Co-TMH clusters generate on the nanobubble interface, further favoring the formation of internal nanocages and porous structures. On the other hand, a fast diffusion leads to rapid nanobubbles generation, aggregation and reshaping, inducing layered structure formation. Inspired by in-situ observation, we further synthesize porous Co-TMH at − 80 ℃ under inhibited diffusion conditions, which exhibits excellent catalytic performance on CO2 reduction reaction.</p

    Detection of DNA oligonucleotides with base mutations by terahertz spectroscopy and microstructures

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    <div><p>DNA oligonucleotides with a 5-base mutation at the 3'-terminus were investigated by terahertz (THz) spectroscopy in a marker-free manner. The four single-stranded oligonucleotides with 17nt have been detected with specificity on a microfluidic chip, and corroborated by spectral measurements with split-ring resonators. The number of hydrogen bonds formed between the oligonucleotide and its surrounding water molecules, deemed a key contribution to the THz absorption of biological solutions, was explored by molecular dynamics simulations to explain the experimental findings. Our work underlies the feasibility of THz spectroscopy combined with microstructures for marker-free detection of DNA, which may form the basis of a prospective diagnostic tool for studying genic mutation.</p></div
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