16 research outputs found

    Anti-Ramsey Numbers in Complete k-Partite Graphs

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    The anti-Ramsey number ARG,H is the maximum number of colors in an edge-coloring of G such that G contains no rainbow subgraphs isomorphic to H. In this paper, we discuss the anti-Ramsey numbers ARKp1,p2,…,pk,Tn, ARKp1,p2,…,pk,ℳ, and ARKp1,p2,…,pk,C of Kp1,p2,…,pk, where Tn,ℳ, and C denote the family of all spanning trees, the family of all perfect matchings, and the family of all Hamilton cycles in Kp1,p2,…,pk, respectively

    Error Source Analysis and Correction of GF-3 Polarimetric Data

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    The GaoFen-3 (GF-3) satellite is the first polarimetric synthetic aperture radar (PolSAR) satellite in China. With a designed in-orbit life of 8 years, it will provide large amounts of PolSAR data for ocean monitoring, disaster reduction, and many other applications. The polarimetric data quality is essential for all these applications, so the analysis and calibration of the polarimetric error sources are very important for GF-3. In this study, we established a full-link error model for GF-3 PolSAR system. Based on this model, we comprehensively analyzed the quantitative effects of the main error sources including the composition, figured out characteristics of the phase imbalance introduced by the antenna, and pointed out the error sources which have to be corrected. Furthermore, the polarimetric correction method for GF-3 PolSAR system is proposed. Finally, assisted by several external calibration experiments, polarimetric errors of GF-3 data are efficiently corrected during in-orbit-test phase

    The similarity of elements in multi-principle element alloys based on a new criterion for phase constitution

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    Prediction of the phase constitution of the multi-principle elements alloys (MPEAs) with various element numbers is important for alloy design and performance optimization. Herein, valence electron density parameter, α, is proposed as an improvement of the valence electron concentration by including the impact of atom volumes. The phase constitution of numerous MPEAs is well predicted by the priori α-ΔHmix(enthalpy of mixing) criterion, evidenced by the distinguishing of FCC single phase, FCC and BCC dual-phase and BCC single phase. The similarity of elements in MPEAs is evaluated by the derivative of α and ΔHmixwith respect to atomic percentage, which successfully predicts the phase constitution of CrFeNi with addition of Ti, Zr, Al, Cr, Fe, Ni, Co and Cu. This work provides valuable insights into priori judgement of the phase constitution of MPEAs in the view of the relationship between elements

    A High-Resolution SAR Focusing Experiment Based on GF-3 Staring Data

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    Spotlight synthetic aperture radar (SAR) is a proven technique, which can provide high-resolution images as compared to those produced by traditional stripmap SAR. This paper addresses a high-resolution SAR focusing experiment based on Gaofen-3 satellite (GF-3) staring data with about 55 cm azimuth resolution and 240 MHz range bandwidth. In staring spotlight (ST) mode, the antenna always illuminates the same scene on the ground, which can extend the synthetic aperture. Based on a two-step processing algorithm, some special aspects such as curved-orbit model error correction, stop-and-go correction, and antenna pattern demodulation must be considered in image focusing. We provide detailed descriptions of all these aspects and put forward corresponding solutions. Using these suggested methods directly in an imaging module without any modification for other data processing software can make the most of the existing ground data processor. Finally, actual data acquired in GF-3 ST mode is used to validate these methodologies, and a well-focused, high-resolution image is obtained as a result of this focusing experiment

    Effectiveness of eHealth Self-management Interventions in Patients With Heart Failure: Systematic Review and Meta-analysis

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    BackgroundHeart failure (HF) is a common clinical syndrome associated with substantial morbidity, a heavy economic burden, and high risk of readmission. eHealth self-management interventions may be an effective way to improve HF clinical outcomes. ObjectiveThe aim of this study was to systematically review the evidence for the effectiveness of eHealth self-management in patients with HF. MethodsThis study included only randomized controlled trials (RCTs) that compared the effects of eHealth interventions with usual care in adult patients with HF using searches of the EMBASE, PubMed, CENTRAL (Cochrane Central Register of Controlled Trials), and CINAHL databases from January 1, 2011, to July 12, 2022. The Cochrane Risk of Bias tool (RoB 2) was used to assess the risk of bias for each study. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) criteria were used to rate the certainty of the evidence for each outcome of interest. Meta-analyses were performed using Review Manager (RevMan v.5.4) and R (v.4.1.0 x64) software. ResultsIn total, 24 RCTs with 9634 participants met the inclusion criteria. Compared with the usual-care group, eHealth self-management interventions could significantly reduce all-cause mortality (odds ratio [OR] 0.83, 95% CI 0.71-0.98, P=.03; GRADE: low quality) and cardiovascular mortality (OR 0.74, 95% CI 0.59-0.92, P=.008; GRADE: moderate quality), as well as all-cause readmissions (OR 0.82, 95% CI 0.73-0.93, P=.002; GRADE: low quality) and HF-related readmissions (OR 0.77, 95% CI 0.66-0.90, P<.001; GRADE: moderate quality). The meta-analyses also showed that eHealth interventions could increase patients’ knowledge of HF and improve their quality of life, but there were no statistically significant effects. However, eHealth interventions could significantly increase medication adherence (OR 1.82, 95% CI 1.42-2.34, P<.001; GRADE: low quality) and improve self-care behaviors (standardized mean difference –1.34, 95% CI –2.46 to –0.22, P=.02; GRADE: very low quality). A subgroup analysis of primary outcomes regarding the enrolled population setting found that eHealth interventions were more effective in patients with HF after discharge compared with those in the ambulatory clinic setting. ConclusionseHealth self-management interventions could benefit the health of patients with HF in various ways. However, the clinical effects of eHealth interventions in patients with HF are affected by multiple aspects, and more high-quality studies are needed to demonstrate effectiveness

    Preliminary results from applying satellite-tracking on snow leopards for the first time in China

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    The lack of snow leopards telemetry studies in China has hampered researchers in studying the movement ecology and home range sizes of snow leopards, the knowledge gap of which has affected effective planning and improvement of snow leopard protected areas in China. In 2021, we conducted China’s first snow leopard satellite-tracking project in Qilianshan National Park, China, one of the most representative mountain areas of snow leopard habitat. The outcomes of the research aims to apply gained understanding on snow leopard home range to enhance management and planning of snow leopard protected area. Here we summarize the preliminary home range results on the first three satellite-tracked snow leopards in China. The three snow leopards were followed between 3 and 6 months yielding a total of 7845 GPS locations. Using 95% MCP, 95% KDE, and aLoCoH, home range estimates of tracked individuals ranged from 106 to 872 km2, 92 – 783 km2, and 47 − 261 km2, respectively. Our preliminary results provide the first home range estimates of snow leopards in China and marks the need for further studies in Qilianshan National Park by implicating potential new aspects of how age, gender and habitat may contribute to snow leopard home range
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