LRPL-VIO: A Lightweight and Robust Visual-Inertial Odometry with Point and Line Features.

Visual-inertial odometry (VIO) algorithms, fusing various features such as points and lines, are able to improve their performance in challenging scenes while the running time severely increases. In this paper, we propose a novel lightweight point-line visual-inertial odometry algorithm to solve this problem, called LRPL-VIO. Firstly, a fast line matching method is proposed based on the assumption that the photometric values of endpoints and midpoints are invariant between consecutive frames, which greatly reduces the time consumption of the front end. Then, an efficient filter-based state estimation framework is designed to finish information fusion (point, line, and inertial). Fresh measurements of line features with good tracking quality are selected for state estimation using a unique feature selection scheme, which improves the efficiency of the proposed algorithm. Finally, validation experiments are conducted on public datasets and in real-world tests to evaluate the performance of LRPL-VIO and the results show that we outperform other state-of-the-art algorithms especially in terms of speed and robustness.

Levitated 2D manipulation on dielectric metasurface by the tuning of polarization states.

In this Letter, we have proposed a particle manipulation system based on a polarization-dependent dielectric metasurface (PDM), which enables far-field trapping and 2D arbitrary transporting. Based on flexible phase manipulation, by tuning the size and angle of meta-atoms, polarization-selective focusing in different modules of the metasurface can be realized. Then, when those regional focuses are continuously lighted in a relay way, the trapped particle at the focus could be delivered to the next one. When six different characteristic polarization states are tuned in order, the trapped particle could be transported to any adjacent hot spots so that 2D manipulation can be realized in an extended range. With the consideration of the Brownian motion, our simulation results show that the success rate of the particle transport can reach more than 96.0%, even after 20 periods when excited at the wavelength of 1064 nm with a power density of 0.15 mW/µm2. We believe that our research provides a new and promising method for particle manipulation and furthers on-chip optofluidic applications.

ERK1/2-dependent activity of SOX9 is required for sublytic C5b-9-induced expression of FGF1, PDGFα, and TGF-ß1 in rat Thy-1 nephritis.

Mesangial proliferative glomerulonephritis (MsPGN) and its related rat model Thy-1 nephritis (Thy-1N) are associated with C5b-9 deposition and are characterized by proliferation of glomerular mesangial cell (GMC) and expansion of extracellular matrix (ECM) expansion, alongside overexpression of multiple growth factors. Although fibroblast growth factor 1 (FGF1), platelet-derived growth factor alpha (PDGFα), and transforming growth factor beta 1 (TGF-ß1) are well known for their proproliferative and profibrotic roles, the molecular mechanisms responsible for regulating the expression of these growth factors have not been thoroughly elucidated. In this study, we found that sublytic C5b-9 induction of sex-determining region Y-box 9 (SOX9) transactivated FGF1, PDGFα, and TGF-ß1 genes in GMCs, resulting in a significant increase in their mRNA and protein levels. Besides, sublytic C5b-9 induction of activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) phosphorylated SOX9 at serine 181 and serine 64, which enhanced SOX9's ability to transactivate FGF1, PDGFα, and TGF-ß1 genes in GMCs. Furthermore, we demonstrated that inhibiting ERK1/2 activation or silencing either ERK1/2 or SOX9 gene led to reduced SOX9 phosphorylation, decreased generation of FGF1, PDGFα, and TGF-ß1, and ameliorated glomerular injury in rat Thy-1N. Overall, these findings suggest that expression of FGF1, PDGFα, and TGF-ß1 is promoted by ERK1/2-mediated phosphorylation of SOX9, which may provide a valuable insight into the pathogenesis of MsPGN and offer a potential target for the development of novel treatment strategies for MsPGN.

Multimode interference in topological photonic heterostructure.

In this Letter, topological photonic heterostructures, which are composed of finite-size photonic crystals with different topological phases, are proposed. The coupled topological edge states (CTESs), which originate from the coupling between topological edge states, are found. By using the finite element method, the multimode interference effect of CTESs is predicted and investigated. Paired and symmetrical interferences are discussed, and the respective imaging positions are calculated. In addition, the multimode interference effect is topologically protected when introducing disorders. As examples of application, frequency and power splitters of topological edge states based on the multimode interference effect are designed and demonstrated numerically. Our findings pave a new, to the best of our knowledge, way of designing topological photonic integrated circuit applications such as filters, couplers, multiplexers, and so on.

A framework for assessing the effects of afforestation and South-to-North Water Transfer on nitrogen and phosphorus uptake by plants in a critical riparian zone.

The uptake of nitrogen (N) and phosphorus (P) by plants in riparian zones can significantly decrease the water pollution risk. Moreover, the vegetation area in riparian zone can be impacted by raising of water level and afforestation. As the largest reservoir in North China, the Miyun Reservoir is affected by the South-to-North Water Transfer (SNWT) and large-scale afforestation. However, few efficient technology frameworks that can be used to assess the effects of similar anthropogenic projections on N and P uptake by plants at riparian zone catchment scale have been reported. Therefore, this study proposed a framework including an ecological simulation tool coupled with multi-source data and scenario setting methods to identify the effects of these two projects on the uptake of N and P by plants in Miyun Reservoir riparian zone from April to September in 2015. The results show that the total N and P uptake by plants in Miyun Reservoir riparian zone are 1214.18 t and 148.66 t in growing seasons. After afforestation, the N (P) removal will increase by 2.56 (2.17) times in the impacted area (below 160 m in elevation). When the water level rises to 150 m in elevation, the joint effects of afforestation and SNWT will increase the total N and P removals by 851.18 t and 83.33 t. This implies that the afforestation can offset the negative effect on N (P) removal caused by SNWT. Overall, this study can provide useful scientific reference for the design and effective management of the riparian zone.

The response of marigold (Tagetes erecta Linn.) to ozone: impacts on plant growth and leaf physiology.

Progressively increasing ozone (O3) concentrations pose a potential threat to the value of marigold (Tagetes erecta Linn.), a plant widely used in urban landscaping. The response of marigold to elevated O3 has been reported earlier, but the mechanisms underlying the O3 effect have not been clearly elucidated. In the present study, we exposed marigold "Moonsong Deep Orange" plants to elevated O3, including ambient non-filtered air (NF) plus 60 ppb (NF+60) and 120 ppb (NF+120) O3, to assess visible injury and the possible physiological consequences of this pollutant. Yellow lesions appeared after 4 days under NF+120 treatment and 12 days under NF+60 treatment, with 85.6% and 36.8% of the leaves being injured at harvest time, respectively. Compared with NF, NF+60 inhibited leaf photosynthesis, stem-diameter growth, and biomass production significantly, while the parameters were decreased more by NF+120. Although the stomatal conductance decreased under elevated O3 exposure, the O3 flux into leaves increased by 28.0-104.8% under NF+60 treatment and 57.5-145.6% under NF+120 treatment. The total ascorbic acid (ASA) content increased due to elevated O3 exposure, while the reduced ASA content did not, resulting in a decreased ratio of reduced to total ASA. A lower level of jasmonic acid (JA) was observed under elevated O3 exposure. In conclusion, the impacts of elevated O3 on marigold plants may be ascribed to increased O3 flux into leaves and reduced protective capacity of leaves to convert oxidized to reduced ASA and synthesize endogenous JA.

Effects of elevated O3 exposure on nutrient elements and quality of winter wheat and rice grain in Yangtze River Delta, China.

With the open-top chambers (OTCs) in situ in Yangtze River Delta, China in 2007 and 2008, the effects of elevated O3 exposure on nutrient elements and quality of winter wheat and rice grain were investigated. Grain yield per plant of winter wheat and rice declined in both years. The N and S concentrations increased under elevated O3 exposure in both years and C-N ratios decreased significantly. The concentrations of K, Ca, Mg, P, Mn, Cu and Zn in winter wheat and the concentrations of Mg, K, Mn and Cu in rice increased. The concentrations of protein, amino acid and lysine in winter wheat and rice increased and the concentration of amylose decreased. The increase in the nutrient concentration was less than the reduction of grain yield in both winter wheat and rice, and, hence, the absolute amount of the nutrients was reduced by elevated O3.

Effects of elevated O3 concentration on winter wheat and rice yields in the Yangtze River Delta, China.

The effects of a continuing rise of ambient ozone on crop yield will seriously threaten food security in China. In the Yangtze River Delta, a rapidly developing and seriously air polluted region in China, innovative open-top chambers have been established to fumigate winter wheat and rice in situ with elevated O(3). Five years of study have shown that the yields of wheat and rice decreased with increasing O(3) concentration. There were significant relationships between the relative yield and AOT40 (accumulated hourly O(3) concentration over 40 ppb) for both winter wheat and rice. Winter wheat was more sensitive to O(3) than rice. O(3)-induced yield declines were attributed primarily to 1000-grain weight and harvest index for winter wheat, and attributed primarily to grain number per panicle and harvest index for rice. Control of ambient O(3) pollution and breeding of O(3) tolerant crops are urgent to guarantee food security in China.

Soil warming effect on net ecosystem exchange of carbon dioxide during the transition from winter carbon source to spring carbon sink in a temperate urban lawn.

The significant warming in urban environment caused by the combined effects of global warming and heat island has stimulated widely development of urban vegetations. However, it is less known of the climate feedback of urban lawn in warmed environment. Soil warming effect on net ecosystem exchange (NEE) of carbon dioxide during the transition period from winter to spring was investigated in a temperate urban lawn in Beijing, China. The NEE (negative for uptake) under soil warming treatment (temperature was about 5 degrees C higher than the ambient treatment as a control) was -0.71 micromol/(m2 x sec), the ecosytem was a CO2 sink under soil warming treatment, the lawn ecosystem under the control was a CO2 source (0.13 micromol/(m2 x sec)), indicating that the lawn ecosystem would provide a negative feedback to global warming. There was no significant effect of soil warming on nocturnal NEE (i.e., ecosystem respiration), although the soil temperature sensitivity (Q10) of ecosystem respiration under soil warming treatment was 3.86, much lower than that in the control (7.03). The CO2 uptake was significantly increased by soil warming treatment that was attributed to about 100% increase of alpha (apparent quantum yield) and Amax (maximum rate of photosynthesis). Our results indicated that the response of photosynthesis in urban lawn is much more sensitive to global warming than respiration in the transition period.

Preliminary report on methane emissions from the Three Gorges Reservoir in the summer drainage period.

Recently reported summertime methane (CH4) emissions (6.7 +/- 13.3 mg CH4/(m2 x hr)) from newly created marshes in the drawdown area of the Three Gorges Reservoir (TGR), China have triggered broad concern in academic circles and among the public. The CH4 emissions from TGR water surfaces and drawdown areas were monitored from 3rd June to 16th October 2010 with floating and static chambers and gas chromatography. The average CH4 emission flux from permanently flooded areas in Zigui, Wushan and Yunyang Counties was (0.33 +/- 0.09) mg CH4/(m2 x hr). In half of these hottest months of the year, the wilderness, cropland and deforested drawdown sites were aerobic and located above water level, and the CH4 emissions were very small, ranging from a sink at 0.12 mg CH4/(m2 x hr) to a source at 0.08 mg CH4/(m2 x hr) except for one mud-covered site after flood. Mean CH4 emission in flooded drawdown sites was 0.34 mg CH4/(m2 x hr). The emissions from the rice paddy sites in the drawdown area were averaged at (4.86 +/- 2.31) mg CH4/(m2 x hr). Excepting the rice-paddy sites, these results show much lower emission levels than previously reported. Our results indicated considerable spatial and temporal variation in CH4 emissions from the TGR. Human activities and occasional events, such as flood, may also affect emission levels. Long-term CH4 measurements and modeling in a large region are necessary to accurately estimate greenhouse gas emissions from the TGR.

Effects of elevated ozone on growth and yield of field-grown rice in Yangtze River Delta, China.

With rapid industrialization and urbanization in the Yangtze Delta, China, the tropospheric ozone concentration has increased to levels that induce crop yield loss. Rice, a widely grown crop in China, was investigated in field-established, open-top chambers. Four treatments were used: charcoal-filtered air (CF), non-charcoal-filtered air (NF), and charcoal-filtered air with two levels of additional ozone (O3-1 and O3-2). The AOT40s (accumulated hourly mean ozone concentration above 40 ppbv) were 0, 0.91, 23.24, and 39.28 ppmv x h for treatment of CF, NF, O3-1, and O3-2, respectively. The rice height and biomass were reduced in the elevated ozone concentration. Less organic matter partitioning to roots under the elevated ozone significantly decreased rice root activity. The yield loss was 14.3% and 20.2% under O3-1 and O3-2 exposure, respectively. This was largely caused by a reduction in grain weight per panicle.

[Effects of elevated ozone on rice (Oryza sativa L.) leaf lipid peroxidation and antioxidant system].

With rice (Oryza sativa L.) cultivar 3694 Fan as test material, and by using open top chambers, the effects of different ozone (O3) concentration on the leaf soluble protein content, lipid peroxidation, and antioxidant system were applied. Three treatments were applied, i.e., charcoal-filtered air (CF, 20 nl O3 x L(-1)), non-filtered ambient air (NF, 40 nl O3 x L(-1)), and elevated O3 (EO, 75 nl O3 x L(-1)). The results showed that there were no significant differences in the test variables between treatments CF and NF. Compared with CF, EO induced a significant decrease of soluble protein content and significant increases of H2O2 and ASA contents and SOD, CAT and POD activities. In treatment EO, the SOD, CAT and POD activities increased by 93.7%, 39.9% and 312.4%, respectively, as compared with treatment CF, while the APX activity tended to increase at first and decrease then. MDA content had no significant differences among the treatments, indicating that leaf antioxidant system could significantly prevent the lipid peroxidation induced by elevated O3, and rice cultivar 3694 Fan could resist O3 to some extent.