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Intrinsic dimensionality detection criterion based on Locally Linear Embedding

100%

Meng L. , Breitkopf P.

tom Vol. 19 (3)

345--356

In this work, we revisit the Locally Linear Embedding (LLE) algorithm that is widely employed in dimensionality reduction. With a particular interest to the correspondences of the nearest neighbors in the original and embedded spaces, we observe that, when prescribing low-dimensional embedding spaces, LLE remains merely a weight-preserving rather than a neighborhood-preserving algorithm. Thus, we propose a \neighborhood-preserving ratio" criterion to estimate the minimal intrinsic dimensionality required for neighborhood preservation. We validate its efficiency on sets of synthetic data, including S-curve, Swiss roll, and a dataset of grayscale images.

Salt tolerance in two tall wheatgrass species is associated with selective capacity for Kplus over Naplus

80%

Gao Q. , Meng L. , Mao P.-C. , Tian X.-X.

nr 01

Decaploid Elytrigia elongata (tall wheatgrass) is a halophytic relative of wheat that is used to improve salt tolerance of wheat in China. However, the physiological mechanisms for the salt tolerance of decaploid E. elongata remain elusive. To further gain insights into mechanisms important for salt tolerance, we present here a comparative study of salt tolerance in salt-sensitive tetraploid E. elongata (PI578686) and salt-tolerant decaploid E. elongata (PI276399). Results showed that compared with PI578686, PI276399 exhibited a higher relative growth rate and a stronger selective absorption and -transport capacity for K⁺ over Na⁺ under high salt conditions (100–200 mM NaCl). This contributed to maintain lower net Na⁺ uptake rates and more efficiently control Na⁺ transport to the shoot in PI276399 than in PI578686. Meanwhile, this also resulted in lower reductions of tissue K⁺ concentrations as well as of net K⁺ uptake rates in PI276399 compared to PI578686. Taken together, our findings indicate that PI276399 has the stronger selectivity for K⁺ over Na⁺ contributing it to maintain lower Na⁺ uptake and K⁺ loss compared with PI578686 in the presence of high salt, and hence endowing the higher salt tolerance of PI276399.

A novel method to extract vanadium from high-grade vanadium slag: non-salt roasting and alkaline leaching

70%

Liu B. , Meng L. , Zheng S. , Li M. , Wang S.

tom Vol. 54, iss. 3

657--667

A new method using non-salt roasting-alkaline leaching to treat vanadium slag was proposed in this study. The V(III) in vanadium slag is oxidized to V(V) by roasting and the latter can be effectively leached out as vanadate by alkaline leaching. This method possesses distinct advantage of being able to treat high-grade vanadium slag. For the South Africa high-grade vanadium slag, the maximum vanadium recovery of 98% was achieved when the reaction conditions were roasting temperature of 850 °C, roasting time of 2 h, alkali concentration of 30 wt.%, leaching temperature of 210 °C, and leaching time of 2 h. The roasting and leaching mechanisms have been well elucidated based on the XRD and SEM analysis results. The phases transitions of vanadium slag were clearly presented. This work has laid the foundation for the industrial application of non-salt roasting-alkaline leaching and provided new insights into effective extraction of high-grade vanadium slag.