Multisensor image fusion approach utilizing hybrid pre-enhancement and double nonsubsampled contourlet transform

A multisensor image fusion approach established on the hybrid-domain image enhancement and double nonsubsampled contourlet transform (NSCT) is proposed. The hybrid-domain pre-enhancement algorithm can promote the contrast of the visible color image. Different fusion rules are, respectively, selected and applied to obtain fusion results. The double NSCT framework is introduced to obtain better fusion performance than the general single NSCT framework. Experimental outcomes in fused images and performance results demonstrate that the presented approach is apparently more advantageous

Increment of soil phosphorus pool and activation coefficient through long-term combination of NPK fertilizers with manures in black soil

editorial reviewed[Objectives]: Long-term fertilization affects soil phosphorus (P) fraction and availability. The change of soil P and P fractions contents and the availability of soil P under long-term different fertilization were investigated, which will offer scientific support for P management in the black soil.[Methods]: The used longterm fertilization experiment was started in 1990 on a black soil in Gongzhuling City, Jilin Province. The cropping system was continues mono maize. The selected four treatments included no fertilizer (CK), applying urea and potash sulfate (NK), applying urea, super-calcium phosphate and potash sulfate (NPK), and NPK plus pig manure (NPKM). For the three chemical fertilizer treatments, the corresponding inputs were N 165 kg/hm2, P 36 kg/hm2 and K 68 kg/hm2. The pig manure input was 21 t/hm2, and the N-P-K input were 165-75-145 kg/hm2. Soil samples were collected for every five years (1990, 1995, 2000, 2005 and 2010). Using the Hedley sequential extraction method, the total P and Olsen-P and P fraction contents were measured, and the soil P activation coefficient(PAC) was calculated.[Results]: With the extension of the experimental years, the soil total P and Olsen-P contents and PAC in treatments of CK and NK displayed downward trends, while those in NPK and NPKM showed upward trends. Compared with the beginning samples, the soil total P and Olsen-P contents and PAC in NPKM treatment were respectively increased by 88.47%, 12.98 and 6.42 times; and those were decreased by 15.12% and 32.67%, 33.47% in CK and by 12.57%, 52.49% and 2.55% in NK treatment; and the Olsen-P contents and PAC were respectively increased by 1.65 and 2.67 times, and the total P contents were not significantly increased in NPK. The inorganic P was increased significantly in NPK and NPKM treatments, while the organic P was not. The inorganic P was the main fraction of soil P in black soil, accounting for 80.53%-90.43% of the total P. Mid-liable P was the main fraction in the P pool of black soil, and accounted for 50.37%-55.06% of the total P, while labile P fraction accounted for 7.61%-19.02%. The ratio of labile P fraction in total P, especially in inorganic P, was increased significantly in NPK and NPKM treatments. Resin-P, NaHCO3-Pi, NaOH-Pi, Conc. HCl-Pi, Residual-P contents were decreased in CK and NK treatments, Resin-P, NaHCO3-Pi, NaOH-Pi, Dil.HCl-Pi contents were increased and Conc. HCl-Pi, Residual-P contents were decreased in NPK treatment, all inorganic P fractions were increased in NPKM treatment. The variation of Olsen-P was significantly correlated with the contents of Resin-P, NaHCO3-Pi, NaOH-Pi, Conc. HCl-Po, and the coefficient was 0.972, 0.665, 0.860 and 0.605 in turn.[Conclusions]: Long-term combined application of NPK fertilizers plus manure not only has caused the significant increase of total P, Olsen-P contents, but also increased the ratio of labile P to inorganic P, and increased the availability of soil P. Therefore, the combined application of NPK and manure is recommended for the effective improvement of P fertility in black soil. © 2018 Chinese Academy of Agriculture Sciences,Editorial Department of Journal of Plant Nutrition and Fertilizer. All Rights Reserved

Tuning ultrafast electron thermalization pathways in a van der Waals heterostructure

Ultrafast electron thermalization - the process leading to Auger recombination, carrier multiplication via impact ionization and hot carrier luminescence - occurs when optically excited electrons in a material undergo rapid electron-electron scattering to redistribute excess energy and reach electronic thermal equilibrium. Due to extremely short time and length scales, the measurement and manipulation of electron thermalization in nanoscale devices remains challenging even with the most advanced ultrafast laser techniques. Here, we overcome this challenge by leveraging the atomic thinness of two-dimensional van der Waals (vdW) materials in order to introduce a highly tunable electron transfer pathway that directly competes with electron thermalization. We realize this scheme in a graphene-boron nitride-graphene (G-BN-G) vdW heterostructure, through which optically excited carriers are transported from one graphene layer to the other. By applying an interlayer bias voltage or varying the excitation photon energy, interlayer carrier transport can be controlled to occur faster or slower than the intralayer scattering events, thus effectively tuning the electron thermalization pathways in graphene. Our findings, which demonstrate a novel means to probe and directly modulate electron energy transport in nanoscale materials, represent an important step toward designing and implementing novel optoelectronic and energy-harvesting devices with tailored microscopic properties.Comment: Accepted to Nature Physic

Observation of the nonlinear Hall effect under time reversal symmetric conditions

The electrical Hall effect is the production of a transverse voltage under an out-of-plane magnetic field. Historically, studies of the Hall effect have led to major breakthroughs including the discoveries of Berry curvature and the topological Chern invariants. In magnets, the internal magnetization allows Hall conductivity in the absence of external magnetic field. This anomalous Hall effect (AHE) has become an important tool to study quantum magnets. In nonmagnetic materials without external magnetic fields, the electrical Hall effect is rarely explored because of the constraint by time-reversal symmetry. However, strictly speaking, only the Hall effect in the linear response regime, i.e., the Hall voltage linearly proportional to the external electric field, identically vanishes due to time-reversal symmetry. The Hall effect in the nonlinear response regime, on the other hand, may not be subject to such symmetry constraints. Here, we report the observation of the nonlinear Hall effect (NLHE) in the electrical transport of the nonmagnetic 2D quantum material, bilayer WTe2. Specifically, flowing an electrical current in bilayer WTe2 leads to a nonlinear Hall voltage in the absence of magnetic field. The NLHE exhibits unusual properties sharply distinct from the AHE in metals: The NLHE shows a quadratic I-V characteristic; It strongly dominates the nonlinear longitudinal response, leading to a Hall angle of about 90 degree. We further show that the NLHE directly measures the "dipole moment" of the Berry curvature, which arises from layer-polarized Dirac fermions in bilayer WTe2. Our results demonstrate a new Hall effect and provide a powerful methodology to detect Berry curvature in a wide range of nonmagnetic quantum materials in an energy-resolved way

Ceruloplasmin is a novel adipokine which is overexpressed in adipose tissue of obese subjects and in obesity-associated cancer cells

Obesity confers an increased risk of developing specific cancer forms. Although the mechanisms are unclear, increased fat cell secretion of specific proteins (adipokines) may promote/facilitate development of malignant tumors in obesity via cross-talk between adipose tissue(s) and the tissues prone to develop cancer among obese. We searched for novel adipokines that were overexpressed in adipose tissue of obese subjects as well as in tumor cells derived from cancers commonly associated with obesity. For this purpose expression data from human adipose tissue of obese and non-obese as well as from a large panel of human cancer cell lines and corresponding primary cells and tissues were explored. We found expression of ceruloplasmin to be the most enriched in obesity-associated cancer cells. This gene was also significantly up-regulated in adipose tissue of obese subjects. Ceruloplasmin is the body's main copper carrier and is involved in angiogenesis. We demonstrate that ceruloplasmin is a novel adipokine, which is produced and secreted at increased rates in obesity. In the obese state, adipose tissue contributed markedly (up to 22%) to the total circulating protein level. In summary, we have through bioinformatic screening identified ceruloplasmin as a novel adipokine with increased expression in adipose tissue of obese subjects as well as in cells from obesity-associated cancers. Whether there is a causal relationship between adipose overexpression of ceruloplasmin and cancer development in obesity cannot be answered by these cross-sectional comparisons

Detecting Manipulations in Video

This chapter presents the techniques researched and developed within InVID for the forensic analysis of videos, and the detection and localization of forgeries within User-Generated Videos (UGVs). Following an overview of state-of-the-art video tampering detection techniques, we observed that the bulk of current research is mainly dedicated to frame-based tampering analysis or encoding-based inconsistency characterization. We built upon this existing research, by designing forensics filters aimed to highlight any traces left behind by video tampering, with a focus on identifying disruptions in the temporal aspects of a video. As for many other data analysis domains, deep neural networks show very promising results in tampering detection as well. Thus, following the development of a number of analysis filters aimed to help human users in highlighting inconsistencies in video content, we proceeded to develop a deep learning approach aimed to analyze the outputs of these forensics filters and automatically detect tampered videos. In this chapter, we present our survey of the state of the art with respect to its relevance to the goals of InVID, the forensics filters we developed and their potential role in localizing video forgeries, as well as our deep learning approach for automatic tampering detection. We present experimental results on benchmark and real-world data, and analyze the results. We observe that the proposed method yields promising results compared to the state of the art, especially with respect to the algorithm’s ability to generalize to unknown data taken from the real world. We conclude with the research directions that our work in InVID has opened for the future

Mapping Dirac quasiparticles near a single Coulomb impurity on graphene

The response of Dirac fermions to a Coulomb potential is predicted to differ significantly from how non-relativistic electrons behave in traditional atomic and impurity systems. Surprisingly, many key theoretical predictions for this ultra-relativistic regime have not been tested. Graphene, a two-dimensional material in which electrons behave like massless Dirac fermions, provides a unique opportunity to test such predictions. Graphene’s response to a Coulomb potential also offers insight into important material characteristics, including graphene’s intrinsic dielectric constant, which is the primary factor determining the strength of electron–electron interactions in graphene. Here we present a direct measurement of the nanoscale response of Dirac fermions to a single Coulomb potential placed on a gated graphene device. Scanning tunnelling microscopy was used to fabricate tunable charge impurities on graphene, and to image electronic screening around them for a Q = +1|e| charge state. Electron-like and hole-like Dirac fermions were observed to respond differently to a Coulomb potential. Comparing the observed electron–hole asymmetry to theoretical simulations has allowed us to test predictions for how Dirac fermions behave near a Coulomb potential, as well as extract graphene’s intrinsic dielectric constant: ε[subscript g] = 3.0±1.0. This small value of ε[subscript g] indicates that electron–electron interactions can contribute significantly to graphene properties.United States. Office of Naval Research. Multidisciplinary University Research Initiative (Award N00014-09-1-1066)United States. Dept. of Energy. Office of Science (Contract DE-AC02-05CH11231)National Science Foundation (U.S.) (Award DMR-0906539