Over 300-km Transmission of 25 Gb/s Optical SSB NPAM-4 Signal with Electronic Dispersion Pre-compensation and Interference Mitigation

We experimentally demonstrate the interference mitigation in direct-detection of optical SSB signals with Nyquist-PAM-4. At 25 Gb/s, we achieve over 300-km and 500-km SSMF with an average BER of 2.7×10-3 (<HD-FEC) and 9.4×10-3 (<SD-FEC), respectively

Effects of obesity with reduced 25(OH)D levels on bone health in elderly Chinese people: a nationwide cross-sectional study

BackgroundObesity is often accompanied by lower 25(OH)D levels, whereas these two parameters exhibit opposite effects on bone health. It is uncertain what are the effects of lower 25(OH)D levels in obesity on bone health in elderly Chinese people.MethodsA nationally representative cross-sectional analysis of China Community-based Cohort of Osteoporosis (CCCO) was performed from 2016 to 2021, which consisted of 22,081 participants. Demographic data, disease history, Body mass index (BMI), bone mineral density (BMD), the levels of the biomarkers of vitamin D status and those of bone metabolism markers were measured for all participants (N = 22,081). The genes (rs12785878, rs10741657, rs4588, rs7041, rs2282679 and rs6013897) related to 25(OH)D transportation and metabolism were performed in a selected subgroup (N = 6008).ResultsObese subjects exhibited lower 25(OH)D levels (p &lt; 0.05) and higher BMD (p &lt; 0.001) compared with those of normal subjects following adjustment. The genotypes and allele frequency of rs12785878, rs10741657, rs6013897, rs2282679, rs4588 and rs7041 indicated no significant differences among three BMI groups following correction by the Bonferroni’s method (p &gt; 0.05). The levels of total 25(OH)D (ToVD) were significantly different among the GC1F, GC1S and GC2 haplotype groups (p &lt; 0.05). Correlation analysis indicated that ToVD levels were significantly correlated with parathyroid hormone levels, BMD, risk of osteoporosis (OP) and the concentration levels of other bone metabolism markers (p &lt; 0.05). Generalized varying coefficient models demonstrated that the increasing BMI, ToVD levels and their interactions were positively associated with BMD outcomes (p &lt; 0.001), whereas the reduced levels of ToVD and BMI increased the risk of OP, which was noted notably for the subjects with reduced ToVD levels (less than 20.69 ng/ml) combined with decreased BMI (less than 24.05 kg/m2).ConclusionThere was a non-linear interaction of BMI and 25(OH)D. And higher BMI accompanied by decreased 25(OH)D levels is associated with increased BMD and decreased incidence of OP, optimal ranges exist for BMI and 25(OH)D levels. The cutoff value of BMI at approximately 24.05 kg/m2 combined with an approximate value of 25(OH)D at 20.69 ng/ml are beneficial for Chinese elderly subjects

Globe-LFMC 2.0, an enhanced and updated dataset for live fuel moisture content research

Globe-LFMC 2.0, an updated version of Globe-LFMC, is a comprehensive dataset of over 280,000 Live Fuel Moisture Content (LFMC) measurements. These measurements were gathered through field campaigns conducted in 15 countries spanning 47 years. In contrast to its prior version, Globe-LFMC 2.0 incorporates over 120,000 additional data entries, introduces more than 800 new sampling sites, and comprises LFMC values obtained from samples collected until the calendar year 2023. Each entry within the dataset provides essential information, including date, geographical coordinates, plant species, functional type, and, where available, topographical details. Moreover, the dataset encompasses insights into the sampling and weighing procedures, as well as information about land cover type and meteorological conditions at the time and location of each sampling event. Globe-LFMC 2.0 can facilitate advanced LFMC research, supporting studies on wildfire behaviour, physiological traits, ecological dynamics, and land surface modelling, whether remote sensing-based or otherwise. This dataset represents a valuable resource for researchers exploring the diverse LFMC aspects, contributing to the broader field of environmental and ecological research

Signal processing techniques for optical fiber networks

© 2007 Xingwen Yi.At present, optical fiber transmissions are dominated by intensity modulation and direct detection, which fundamentally limit the signal processing capabilities in optical fiber networks. On the other hand, manipulation of optical phase enables advanced signal processing techniques for various applications. This thesis includes three parts and makes contributions in three research areas in optical fiber networks, by applying optical and electronic signal processing techniques. In the first part of the thesis, optical signal processing is employed to realize a novel all-optical label swapping (AOLS) technique using synchronous phase modulation. This technique is shown to address the forwarding speed bottleneck in optical packet switched networks (OPSN). By exploiting the unique symmetry of phase-shift keying (PSK), for the first time, label erasure and insertion are performed in a single step by a phase modulator without wavelength conversion. We also propose and demonstrate a polarization insensitive phase modulator to address the polarization sensitivity of AOLS. Furthermore, we emulate multi-hop all-optical label swapping in a re-circulating loop to investigate the power penalties from the accumulated phase errors and the timing mismatch. Based on the experimental and analytical results, we show that this technique can save wavelength converters significantly if compared with conventional AOLS techniques requiring dedicate wavelength converters

Coherent optical OFDM: has its time come [Invited

There has been growing interest in coherent optical orthogonal frequencydivision multiplexing (CO-OFDM). We aim to present the case that the time for CO-OFDM has come, in terms of the demand from today’s ever-advancing optical networks and the availability of its underlying technologies. We first lay out the signal processing aspect for CO-OFDM and then show a 2�2 multiple-input–multiple-output (MIMO) OFDM representation for the singlemode fiber optical channel. Through numerical simulation and experimental demonstration, we further present and discuss various MIMO-OFDM systems focusing on their polarization-mode dispersion resilience. Among those systems, the 2�1 MIMO-OFDM configuration incorporating polarization-time coding shows promise for optical access networks and broadcast networks. Finally, another class of the frequency-domain equalization techniques, namely, incoherent or coherent optical single-carrier frequency-domain equalization (CO-SCFDE) is discussed and experimentally demonstrated. © 2008 Optica

Removal of Pb, Zn, Cu, Cr and Ni in Iron Tailings by Leaching

In this paper, oxalic acid and EDTA-2Na were used as leaching agents to perform shock leaching tests on Pb, Zn, Cu, Cr and Ni in iron tailings. The effect of different leaching solution concentrations, liquid-solid ratios and shaking times on the removal effect of heavy metals were studied. The changes of heavy metal morphology after leaching were analyzed, and the correlation between leaching content and heavy metal morphology was discussed. The results showed that the removal rates of Pb, Cu, and Cr reached the highest when the oxalic acid concentration was 250, 100, and 200 mmol/L, respectively, and the removal rates were 19.9%, 43.9%, and 4.2%, respectively. The removal effect of Zn and Ni was best when the concentration of EDTA-2Na was 100 and 200 mmol/L, respectively, and the removal rates were 33.2% and 39.4%, respectively. During the oxalic acid leaching process, the removal rates of Cu and Pb gradually increased with the increase of shaking time, and the removal rates of Zn, Ni and Cr tended to be stable after 120 min. EDTA-2Na had little effect on the removal rate of heavy metals with the extension of the shaking time, and it basically stabilized when the shaking time was 60 min. When the liquid-solid ratio was 30:1, the removal effect of heavy metals was relatively good. The morphology of heavy metals after oxalic acid leaching was analyzed, and it was found that the leaching can not only effectively remove the easily migrated forms of heavy metals, but also caused the migration and transformation between heavy metal forms. Correlation analysis found that the correlation coefficients of heavy metal leaching content with exchangeable state and carbonate binding state were 0.930* and 0.996**, respectively. After leaching, the ratios of the exchangeable state and the carbonate-bound state of heavy metals in the iron tailings decreased, and the proportion of the residue state, the iron-manganese oxide-bound state and the organically bound state increased. This improved the stability of iron tailings in the environment, reduced the risk of iron tailings polluting the environment, and provided new ideas and theoretical basis for the harmless iron tailings