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We report a real-time 150 kbps stealth transmission within public optical communication of 10 Gbps dual polarization QPSK. The stealth data is modulated onto the frequency tuning signals of a fast-tuning laser source in the transmitter, which causes slight frequency dithering for the transmitted optical signal. In the receiver, the stealth receiver recovers the stealth data from the estimated frequency offset by the QPSK DSP algorithm. The experiments show the stealth transmission has few impacts on the public channel over a 300â km distance. The proposed method is fully compatible with existing optical transmission systems, and the only hardware change is to upgrade the transmitter laser to support frequency tuning through an external analog port for receiving stealth signal. The proposed stealth scheme can combine with cryptographic protocols to improve the integrated security of the system, and can be used as signaling transport for low level network control to reduce the communication overhead.
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The increasing demand of real-time applications poses a huge challenge to building next-generation radio access network (NG-RAN) with higher stability and lower system complexity. Parallel signal detection (PSD), which aggregates signals of different intermediate frequencies (IFs) on different wavelengths with a single photodiode (PD), becomes a promising candidate for uplink mobile fronthaul with the advantage of low-latency. However, high requirements on the transmitters inhibit the large-scale deployment of radio units (RU). In this paper, we propose an economical, low-latency, multipoint-to-point (MP2P) uplink fronthaul architecture capable of aggregating four end-users with commercial 25G-class optical modules and a single PD. With delta-sigma modulation (DSM), commercial off-the-shelf optical modules can replace analog transmitters in traditional systems. As a demonstration, we aggregated 4 × 380.16-MHz 5â G new radio (NR) orthogonal frequency division multiplexing (OFDM) signals in an IF band with a fixed interval of 400â MHz over 20â km fiber with 4 users.
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Due to the cross phase modulation (XPM) effect, in long-haul high-speed dense wavelength division multiplexing (DWDM) coherent systems, using a low-speed on-off-keying (OOK) format optical supervisory channel (OSC) will introduce extra nonlinear phase noise, which restricts the transmission distance. In this paper, we propose a simple OSC coding method to mitigate the OSC-induced nonlinear phase noise. According to the split-step solution of the Manakov equation, we up-convert the baseband of the OSC signal out of the pass-band of the walk-off term to reduce the spectrum density of XPM phase noise. Experimental results show that the optical signal to noise ratio (OSNR) budget on the 400â G channel of 1280-km transmission is improved by 0.96â dB, which achieves almost the same performance with the no OSC case.
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The physical layer transmission security is a promising technology against security threats. As an effective supplement to the encryption strategy, steganography has received widespread attention. We report a real-time 2 kbps stealth transmission in the 10 Gbps dual polarization QPSK public optical communication. The stealth data is embedded in dither signals via precise and stable bias control technique for a Mach-Zehnder modulator. In the receiver, the stealth data can be recovered from the normal transmission signals by low SNR signal processing and digital down conversion. The stealth transmission has been verified to pose almost no impact on the public channel over a 117 km distance. The proposed scheme is compatible with existing optical transmission systems, so that no new hardware needs to be employed. It can be accomplished and is exceeded economically by adding simple algorithms, which utilizes only a small amount of FPGA resources. The proposed method can cooperate with encryption strategies or cryptographic protocols at different network layers to reduce the communication overhead and improve the overall security of the system.
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We propose and experimentally study a novel, to the best of our knowledge, quantum noise stream cipher (QNSC) secure transmission scheme based on the delta-sigma modulation (DSM) technique. The cooperation of the QNSC and DSM mechanisms makes it possible to transmit an ultrahigh-order encrypted signal in the non-return-to-zero (NRZ) on-off keying (OOK) format. The delivery of the NRZ OOK waveform over the fiber link allows us to send and receive signals using digital ports, instead of high-speed and high-resolution digital-to-analog converters (DACs) and analog-to-digital converters (ADCs) in conventional QNSC systems. Meanwhile, clock synchronization can be achieved by using a simple clock data recovery algorithm. The extra clock signal transmission link in conventional QNSC systems is no longer needed. The proposed scheme is also compatible with wavelength division multiplexing (WDM) systems. In this work, 4 × 12.9 Gbit/s plaintext is encrypted to a 65,536-level QNSC signal and then transmitted over a 10-km standard single-mode fiber. The transmitter and receiver are established by commercial 100G QSFP28 optical modules with clock data recovery. This proposed scheme can be easily deployed in commercial systems due to its minimalist implementation architecture and relatively low hardware cost.
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Conflict management in PAs (Protected Areas) is becoming increasingly important in the context of the rapid development of nature-based tourism. Literature proposes the Index of Conflict tendency between Tourism development and ecological Protection (ICTP) to analyze the tendency of conflict from a spatial perspective, but this index does not consider the factor of seasonality which is important in tourism. The current study considers seasonality and proposes the CVD (Coverage- Variation- Duration) framework to conduct a spatio-temporal analysis of the ICTP. The applied research based on the case of China's V-PAs (a specific category of PAs) reflects that the CVD framework can describe the spatial distribution of the ICTP from a seasonal perspective. The study finds that, among V-PAs in China, 42.16% of the areas with high ICTP of V-PAs have obvious seasonal variations, which shows that PAs conflict management must incorporate the factor of seasonality. The study also shows that 8.98% of V-PAs have large-scale coverage of areas with high ICTP, revealing priorities for conflict management. 3.96% of V-PAs have large-scale coverage of areas with high ICTP showing seasonal changes. Management in these areas should pay attention to seasonal changes to become more effective. The CVD framework proposed in this paper is operable and extendable and can provide analytical tools for PAs conflict management, and promote ecological protection and more sustainable tourism development in PAs.
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Conservación de los Recursos Naturales , Turismo , ChinaRESUMEN
The global economic value of parks through improved mental health of tourists has been estimated at about ten times greater than direct park tourism expenditure. The Chinese term for this health services value is jing hua xin ling, psychological destressing. Here we present the first case where optimal tourist infrastructure is influenced by including mental health. Using a multi-stage, cross-lingual, differential stakeholder method, we analyse conflicts between road- and roadless-access tourism in the very large new Sanjiangyuan National Park, Qinghai, which offers jing hua xin ling to domestic tourists from eastern-seaboard cities. This provides a powerful tourism attraction, and hence economic opportunity, for the region around the park. If these mental health aspects are included, together with their direct and indirect consequences for tourism, then roadlessness is preferable to new roads. Similar infrastructure conflicts occur for park tourism worldwide, and jing hua xin ling can provide a global theoretical framework.
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Despite its prevalence, preeclampsia (PE) remains unclear as to its etiology. Here, we aimed to investigate the mechanisms regulating differences in the gene expression of zinc-finger protein 516 (ZNF516) in the placenta. The expression of the placental ZNF516 gene and its association with critical clinical markers were verified, and a rigorous correlation analysis was conducted. With a dual-luciferase reporter gene assay, microRNA targeting the ZNF516 gene was predicted and confirmed. Finally, the molecular processes associated with ZNF516 were explored via microarray and bioinformatic analyses. In hypoxic conditions, miR-371-5p expression was reduced, resulting in ZNF516 expression being induced. Moreover, ZNF516 was shown to hinder trophoblast cell migration and invasion while enhancing trophoblast cell death in various in vitro cellular assays, such as cell counting kit-8, colony formation, wound healing, and Transwell assays. Our findings reveal a new regulatory network facilitated by ZNF516. ZNF516 overexpression inhibits trophoblast growth, movement, and penetration, potentially causing problems with placenta formation with the help of miR-371-5p suppression.
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Movimiento Celular , Proliferación Celular , MicroARNs , Preeclampsia , Trofoblastos , MicroARNs/genética , MicroARNs/metabolismo , Humanos , Trofoblastos/metabolismo , Movimiento Celular/genética , Proliferación Celular/genética , Femenino , Embarazo , Preeclampsia/genética , Preeclampsia/metabolismo , Preeclampsia/patología , Placenta/metabolismoRESUMEN
Arsenic trioxide (ATO) is well known for its inhibitory effects on cancer progression, including lung adenocarcinoma (LUAD), but the molecular mechanism remains elusive. This study aimed to investigate the roles of ATO in regulating LUAD stem cells (LASCs) and the underlying mechanisms. To induce LASCs, cells cultured in an F12 medium, containing B27, epidermal growth factor, and basic fibroblast growth factor, induced LASCs. LASCs stemness was assessed through tumor sphere formation assay, and percentages of CD133+ cells were detected by flow cytometry. The Cell Counting Kit-8 method was used to assess LASCs viability, while reactive oxygen species (ROS) and iron ion levels were quantitated by fluorescence microscopy and spectrophotometry, respectively, and total m6A levels were measured by dot blot. Additionally, LASCs mitochondrial alterations were analyzed via transmission electron microscopy. Finally, the tumorigenicity of LASCs was assessed using a cancer cell line-based xenograft model. Tumor sphere formation and CD133 expression were used to validate the successful induction of LASCs from A549 and NCI-H1975 cells. ATO significantly inhibited proliferation, reduced ZC3H13 expression and total m6A modification levels, and increased ROS and iron ion content, but repressed sphere formation and CD133 expression in LASCs. ZC3H13 overexpression or ferrostatin-1 treatment abrogated LASCs stemness inhibition caused by ATO treatment, and interference with ZC3H13 inhibited LASCs stemness. Furthermore, the promotion of LASCs ferroptosis by ATO was effectively mitigated by ZC3H13 overexpression, while interference with ZC3H13 further promoted ferroptosis. Moreover, si-ZC3H13 promoted ferroptosis and impaired stemness in LASCs, which ferrostatin-1 abrogated. Finally, ZC3H13 overexpression alleviated the inhibitory effects of ATO on LASCs tumorigenicity. Taken together, ATO treatment substantially impaired the stemness of LUAD stem cells by promoting the ferroptosis program, which was mediated by its ZC3H13 gene expression inhibition to suppress m6A medication.
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Tourism activities may interfere with the landscape pattern as a type of human activity. Scientific decision-making in the river basin's tourism development requires a precise understanding of the tourism activities' complicated effects on landscape patterns. The research object is to ascertain the direction and magnitude of the influence of tourism activities on the landscape pattern in the Xin'an River Basin. The response index (RI) was calculated by comparing the dynamic characteristics of landscape pattern metrics and Morphological Spatial Pattern Analysis (MSPA) inside and outside the 24 scenic areas. The results show the RI (=-2.56) of the scenic areas is eight times higher than that of the other areas, which indicates the intensity of the tourism activities' negative impact on the landscape pattern. Cultural and low-level scenic areas have more serious landscape fragmentation in general, through the comparative analysis of different types and scales of scenic areas. Combined with the analysis of tourism socio-economic data, scenic area construction is the main factor leading to landscape fragmentation. This study is an effective review of the impact of China's tourism industry on landscape patterns in the past 40 years, and the proposed RI will better help to quantify the effect of tourism activities on landscape patterns.
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Ríos , Turismo , Humanos , Actividades Humanas , Análisis Espacial , ChinaRESUMEN
Conservationists recognize that protected areas (PAs) have limited prospects without the involvement and support of local people. As a governance strategy, community participation is to implement the coordinated development of communities and PAs. However, the effects of community participation on national park governance have rarely been tested. Therefore, the present study used a mixed-method approach that is derived from the International Union for Conservation of Nature (IUCN) green list of protected and conserved areas (PCA) conservation outcomes framework, calibrated to the indigenous peoples and local communities' (IPLCs) self-assessments about the outcomes of community participation on national park governance to explore the community participation effects. Our results show that management efficiency controls governance outcomes. Potatso National Park's transformation from the tourism development model to national park is still ongoing, and there exists quite a few problems. We conclude that a successful national park governance as envisaged by the "ecological civilization" paradigm requires a balance of government regulation, participation of various stakeholders in decision-making and discussion, compensation, as well as sustainable access to environmental resources by the affected populations.
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Conservación de los Recursos Naturales , Parques Recreativos , Humanos , Conservación de los Recursos Naturales/métodos , Participación de la Comunidad , Civilización , ChinaRESUMEN
With the rapid development of tourism industry in China since 1980, the country has experienced an increasing use of its natural and cultural environment for tourism, resulting in tourism resources being adversely impacted in many tourism destinations. This paper described the research progress in tourism impacts on the environment in the context of China through a review of the growing literature in this field. Specifically, research on tourism impacts on the biophysical and socio-cultural environments, tourism carrying capacity, environmental quality assessment, and measures for the protection and management of tourism resources was reviewed. The review found that the majority of research was qualitative and descriptive in nature, and there was a lack of case studies and theoretical development. Future research should focus on the evaluation of environmental impacts, particularly those gradual cumulative impacts on the tourism environment; examination of the quantitative relationship between the impact and the level of tourism use for different activities; development of methods to estimate the carrying capacity; and understanding of positive impacts of tourism.
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Ambiente , Viaje , China , Cultura , Contaminación Ambiental , RecreaciónRESUMEN
Ecological security early warning, as an important content of ecological security research, is of indicating significance in maintaining regional ecological security. Based on driving force, pressure, state, impact and response (D-P-S-I-R) framework model, this paper took Zhoushan Islands in Zhejiang Province as an example to construct the ecological security early warning index system, test degrees of ecological security early warning of Zhoushan Islands from 2000 to 2012 by using the method of variable weight model, and forecast ecological security state of 2013-2018 by Markov prediction method. The results showed that the variable weight model could meet the study needs of ecological security early warning of Zhoushan Islands. There was a fluctuant rising ecological security early warning index from 0.286 to 0.484 in Zhoushan Islands between year 2000 and 2012, in which the security grade turned from "serious alert" into " medium alert" and the indicator light turned from "orange" to "yellow". The degree of ecological security warning was "medium alert" with the light of "yellow" for Zhoushan Islands from 2013 to 2018. These findings could provide a reference for ecological security maintenance of Zhoushan Islands.
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Conservación de los Recursos Naturales , Monitoreo del Ambiente , Modelos Teóricos , China , Ecología , Ecosistema , Islas , Medición de RiesgoRESUMEN
Based on the statistical data of natural ecology and social economy in Jinyintan Grassland Scenic Area in Qinghai Province in 2008, an evaluation index system for the ecological sensitivity of this area was established from the aspects of protected area rank, vegetation type, slope, and land use type. The ecological sensitivity of the sub-areas with higher tourism value and ecological function in the area was evaluated, and the tourism function zoning of these sub-areas was made by the technology of GIS and according to the analysis of eco-environmental characteristics and ecological sensitivity of each sensitive sub-area. It was suggested that the Jinyintan Grassland Scenic Area could be divided into three ecological sensitivity sub-areas (high, moderate, and low), three tourism functional sub-areas (restricted development ecotourism, moderate development ecotourism, and mass tourism), and six tourism functional sub-areas (wetland protection, primitive ecological sightseeing, agriculture and pasture tourism, grassland tourism, town tourism, and rural tourism).
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Ecosistema , Poaceae/crecimiento & desarrollo , Viaje , China , Ecología , Monitoreo del Ambiente , Árboles/crecimiento & desarrolloRESUMEN
Landscape indices provide quantitative information about landscape pattern and predict some ecological processes. Rationality of Wusuli River National Forest Park' general planning program was evaluated by comparatively analyzing the landscape indices change. The results indicated that the number of patch decreased from 413 to 401, Shannon's evenness index increased from 0.755 to 0.787, and predominant index decreased from 25.547 to 24.500. In addition, the network connectivity index, the network circuitry index, and landscape attractive power between scenic spot were increased, and the extent of landscape fragmentation was decreased. So, the planning would improve the landscape pattern, enhance ecosystem stability and landscape quality, and be useful for ecological protection and ecotourism development.