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For the problem of low time-frequency aggregation of the short-time Fourier transform (STFT), which causes the parameter estimation performance degradation of linear frequency modulation (LFM) signals at low signal-to-noise ratio (SNR), second-order synchrosqueezing transform (SSST) is proposed based on the square of STFT amplitude. The time-frequency resolution and energy aggregation are improved by means of squeezing and reassigning the time-frequency spectrum. Meanwhile, in order to decrease the calculation of classical parameter estimation methods, the Hough transform is used for rough estimation, and then the fractional Fourier transform (FRFT) is used for accuracy estimation based on the Renyi entropy. The simulation result shows that higher estimation accuracy is obtained at low SNR, and it has better robustness. [ABSTRACT FROM AUTHOR]

This study examines aspects of virulence to resistant rice varieties among planthoppers and leafhoppers. Using a series of resistant varieties, brown planthopper, Nilaparvata lugens, virulence was assessed in seedlings and early-tillering plants at seven research centers in South and East Asia. Virulence of the whitebacked planthopper, Sogatella furcifera, in Taiwan and the Philippines was also assessed. Phylogenetic analysis of the varieties using single-nucleotide polymorphisms (SNPs) indicated a clade of highly resistant varieties from South Asia with two further South Asian clades of moderate resistance. Greenhouse bioassays indicated that planthoppers can develop virulence against multiple resistance genes including genes introgressed from wild rice species. Nilaparvata lugens populations from Punjab (India) and the Mekong Delta (Vietnam) were highly virulent to a range of key resistance donors irrespective of variety origin. Sogatella furcifera populations were less virulent to donors than N. lugens; however, several genes for resistance to S. furcifera are now ineffective in East Asia. A clade of International Rice Research Institute (IRRI)-bred varieties and breeding lines, without identified leafhopper-resistance genes, were highly resistant to the green leafhopper, Nephotettix virescens. Routine phenotyping during breeding programs likely maintains high levels of quantitative resistance to leafhoppers. We discuss these results in the light of breeding and deploying resistant rice in Asia. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate whether the six-spot-step test (SSST) is more suitable for monitoring walking ability in patients with chronic inflammatory polyneuropathy than the timed 25-foot-walking test (T25FW). In the SSST, participants have to walk as quickly as possible across a field measuring 1 × 5 m, while kicking blocks out of five circles on the floor. Sixty-two patients and 61 controls performed the SSST and T25FW. Patients also performed the overall disability sumscore, INCAT sensory sumscore, Medical Research Council sumscore, and 9-hole-peg-test. Twenty-one patients treated with intravenous immunoglobulin (IVIG) every 4-6 weeks were tested prior to and 2-3 weeks after treatment and judged change in their own clinical condition using the patient global impression of change (PGIC) scale. In patients, SSST ranged from 5.7 to 26.8 s and T25FW ranged from 3.6 to 12.9 s. Intra-class correlation between repeated tests was 0.97 for SSST and 0.95 for T25FW. Correlation with the additional tests was stronger for SSST than T25FW. In IVIG-treated patients, the mean change in walking time was −2.3 s for SSST and −0.6 s for T25FW. The SSST showed larger responsiveness in terms of effect size, standardized response means, and relative efficiency. Both ambulation tests correlated moderately to PGIC. The SSST may be superior to the T25FW in terms of dynamic range, floor effect, and responsiveness which makes the SSST a possible alternative for monitoring walking ability in patients with chronic inflammatory polyneuropathy. [ABSTRACT FROM AUTHOR]

The in situ data of sea surface temperature (SST) were measured onboard the Polar Ship Almirante Maximiano in the southern Shetland Islands between 5 and 23 February 2011. For the simulations, three concentric nested grids have been used at the 9 km, 3 km and 1 km spatial resolution in the simulations of the skin sea surface temperature (SSST) with WRF model. The grids are displaced every day, always centered in the middle position of the ship (latitude/longitude) during transect. The SSST is underestimated in comparison with SST on average 1.5 °C. The real average wind speed observed was 8.7 ms-1. Therefore the amount of mixing between SST and SSST is greater, and the temperature difference between the two layers is smaller, on average 0.5 °C. The underestimation of the model is mean 1 °C. This underestimation directly interfere on the amount of ocean evaporation for the atmosphere, which may cause error in the energy balance. The correlation of the SSST with real SST data was 0.84 and root mean square error 1.87. [ABSTRACT FROM AUTHOR]

This study examines aspects of virulence to resistant rice varieties among planthoppers and leafhoppers. Using a series of resistant varieties, brown planthopper, Nilaparvata lugens, virulence was assessed in seedlings and early-tillering plants at seven research centers in South and East Asia. Virulence of the whitebacked planthopper, Sogatella furcifera, in Taiwan and the Philippines was also assessed. Phylogenetic analysis of the varieties using single-nucleotide polymorphisms (SNPs) indicated a clade of highly resistant varieties from South Asia with two further South Asian clades of moderate resistance. Greenhouse bioassays indicated that planthoppers can develop virulence against multiple resistance genes including genes introgressed from wild rice species. Nilaparvata lugens populations from Punjab (India) and the Mekong Delta (Vietnam) were highly virulent to a range of key resistance donors irrespective of variety origin. Sogatella furcifera populations were less virulent to donors than N. lugens; however, several genes for resistance to S. furcifera are now ineffective in East Asia. A clade of International Rice Research Institute (IRRI)-bred varieties and breeding lines, without identified leafhopper-resistance genes, were highly resistant to the green leafhopper, Nephotettix virescens. Routine phenotyping during breeding programs likely maintains high levels of quantitative resistance to leafhoppers. We discuss these results in the light of breeding and deploying resistant rice in Asia.

Objective The primary objective of this study was to develop a quantitative test to assess ambulation in multiple sclerosis (MS) patients that is more accurate and sensitive than the Timed 25-foot walk (T25FW). For this purpose, we developed the Six Spot Step Test (SSST), which besides speed includes co-ordination and balance, to be a lower limb counterpart to the 9-Hole Peg Test (9HPT). Background The T25FW, which is the ambulation test of the MS Functional Composite (MSFC), reflects only the speed component of walking. The lack of sensitivity to other components of gait adds to the floor effect. Methods and patients In the SSST, the patient is instructed to walk as quickly as possible from one end to the other of a rectangular field measuring 1 × 5 m, while kicking five cylinder blocks out of five circles marked on the floor. Some 151 MS patients with the Expanded Disability Status Scale (EDSS) score 0–6.5 and 64 normal controls performed the SSST and the T25FW. In addition, 41 patients performed the tests twice. Results The range of the SSST (4.7–35.1 seconds) was wider than that of the T25FW (3.5–22.6 seconds). Using control mean +2 SD as cut off, 107 patients had abnormal SSST, while 100 patients had abnormal T25FW. The T25FW (mean) increased 2.1 seconds over the EDSS range of 0–4.0, while the SSST increased 4.9 seconds. The intra-class correlation between repeated tests (r) was 0.95 for the SSST and 0.96 for the T25FW. The correlation between the SSST and the T25FW was high (r=0.92). Conclusion The SSST seems to be superior to the T25FW in terms of dynamic range, floor effect and discriminatory power. The SSST is a relevant alternative for the T25FW as the ambulation component of the MSFC. [ABSTRACT FROM AUTHOR]