Reproductive biology of smooth cordgrass (Spartina alterniflora)

Smooth cordgrass (S. alterniflora) is a perennial grass that dominates the salt marsh in tidal wetlands along the Atlantic and Gulf Coast of North America and has been used for preventing soil erosion and restoring wetlands. Accessions collected from south Louisiana were studied to investigate flowering phenology, pollen viability, crossability, and seed production. S. alterniflora exhibited protogynous flowering where stigmas exserted 2 to 5 days from the floret prior to anthesis. Pollen shed primarily between 8:00 and 10:00 AM. Pollens were viable with average germination of 69% and stigma was receptive after exsertion. Pollen germinated in 15 minutes and pollen tubes reached micropyle in 55 to 75 minutes after contacting stigma. Protogyny could be used to produce controlled hybrid without emasculation and it could reduce tedious labor required for making crosses. S. alterniflora was cross-pollinated with 52% seed set for cross-pollination and 26% for self-pollination. Flowering started in early July and ended by the middle of October with a flowering peak between early September and early October. During the flowering peak, seed set, kernel weight, and seed viability were positively correlated to flowering date while unfilled and total seeds/panicle were negatively correlated with flowering date. Kernel weight, flowering date, seed weight/panicle, and panicle height were positively correlated with seed set. Plant flowering during the peak period might produce better seed set and seed weight. Field investigation showed an average seed set of 47% with range from 0 to 94% for S. alterniflora, which provided large opportunity for selection. Several lines with improved characteristics were selected and would be valuable for recurrent selection program with an objective of developing improved S. alterniflora populations. However, short term breeding objective should be focused on selection of plants from native collection that have high percentage of seed set, germination, and broad adaptability

The effect of ions doping on the rheological properties of ferrite ferrofluids

A series of ferrite nanoparticles were synthesized via ion doping and then were coated by surfactant and dispersed in perfluorinated polyether oil (PFPE-oil), and the various ferrite ferrofluids were obtained. The scanning electron microscope was used to characterize the morphology of particles and the dispersed state of ferrofluid, energy-dispersive spectroscopy was used to study the chemical composition of particles, fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis were used to study the coated effect of PFPE-acids on particles, vibrating sample magnetometer was used to research the magnetization curves of ferrite particles, and the rheological property of the ferrite ferrofluids was studied by a rheometer. The results show that Zn2+, Mn2+/Zn2+, and Dy3+ ions were doped in the ferrite nanoparticles with a size less than 50 nm. The four kinds of ferrite nanoparticles have the characteristics of super-paramagnetic materials, and the M-T curves decrease with increasing temperature, while their decline rates are notably different. The ferrite particles are coated with PFPE acids chemically, and the ferrofluids have well dispersion stability. The rheological properties of the ferrite ferrofluids change with the variation of ion doping, magnetic field strength, temperature, etc. The magnetism and viscosity of ferrite ferrofluids are regularly affected by ion doping, and the results will have a great significance on basic research and related applications

MMPosE: Movie-induced multi-label positive emotion classification through EEG signals

Emotional information plays an important role in various multimedia applications. Movies, as a widely available form of multimedia content, can induce multiple positive emotions and stimulate people's pursuit of a better life. Different from negative emotions, positive emotions are highly correlated and difficult to distinguish in the emotional space. Since different positive emotions are often induced simultaneously by movies, traditional single-target or multi-class methods are not suitable for the classification of movie-induced positive emotions. In this paper, we propose TransEEG, a model for multi-label positive emotion classification from a viewer's brain activities when watching emotional movies. The key features of TransEEG include (1) explicitly modeling the spatial correlation and temporal dependencies of multi-channel EEG signals using the Transformer structure based model, which effectively addresses long-distance dependencies, (2) exploiting the label-label correlations to guide the discriminative EEG representation learning, for that we design an Inter-Emotion Mask for guiding the Multi-Head Attention to learn the inter-emotion correlations, and (3) constructing an attention score vector from the representation-label correlation matrix to refine emotion-relevant EEG features. To evaluate the ability of our model for multi-label positive emotion classification, we demonstrate our model on a state-of-the-art positive emotion database CPED. Extensive experimental results show that our proposed method achieves superior performance over the competitive approaches

Reconstruction of surface structure of MoBiTeO/SiO2 catalyst during propane selective oxidation

The catalytic performance of MoBiTeO/SiO2 for selective oxidation of propane to acrolein was investigated, and the catalyst was characterized by means of X-ray powder diffraction, in-situ laser Raman spectroscopy, in-situ laser Raman spectroscopy, and X-ray photoelectron spectroscopy. The results showed that Te-polymolybdate species were the main active phase on the fresh catalyst. Under the conditions of 570 degrees C and C3H8/O-2/N-2 = 1.2/1/4, some Te species in the catalyst were reduced to metal Te which was volatilized during the reaction, and therefore the active surface phase of the catalyst was reconstructed, leading to the formation of MoO3 species. Along with the active surface reconstruction, both the conversion of propane and the selectivity for acrolein were increased, which was attributed to the synergistic effect between Te-polymolybdate and MoO3

An Unusual Topological Structure of the HIV-1 Rev Response Element

SummaryNuclear export of unspliced and singly spliced viral mRNA is a critical step in the HIV life cycle. The structural basis by which the virus selects its own mRNA among more abundant host cellular RNAs for export has been a mystery for more than 25 years. Here, we describe an unusual topological structure that the virus uses to recognize its own mRNA. The viral Rev response element (RRE) adopts an “A”-like structure in which the two legs constitute two tracks of binding sites for the viral Rev protein and position the two primary known Rev-binding sites ∼55 Å apart, matching the distance between the two RNA-binding motifs in the Rev dimer. Both the legs of the “A” and the separation between them are required for optimal RRE function. This structure accounts for the specificity of Rev for the RRE and thus the specific recognition of the viral RNA