Interference in transport through double barriers in interacting quantum wires

We investigate interference effects of the backscattering current through a double-barrier structure in an interacting quantum wire attached to noninteracting leads. Depending on the interaction strength and the location of the barriers, the backscattering current exhibits different oscillation and scaling characteristics with the applied voltage in the strong and weak interaction cases. However, in both cases, the oscillation behaviors of the backscattering current are mainly determined by the quantum mechanical interference due to the existence of the double barriers.Comment: 6 pages, 3 fig

Proteomic responses reveal the differential effects induced by cadmium in mussels Mytilus galloprovincialis at early life stages

Cadmium (Cd) has become an important metal contaminant and posed severe risk on the organisms in the coastal environments of the Bohai Sea. Marine mussel Mytilus galloprovincialis is widely distributed along the Bohai coast and consumed as seafood by local residents. Evidences indicate that the early stages of marine organisms are more sensitive to metal contaminants. In this study, we applied two-dimensional electrophoresis-based proteomics to characterize the biological effects of Cd (50 mu g L-1) in the early life stages (D-shape larval and juvenile) of mussels. The different proteomic responses demonstrated the differential responsive mechanisms to Cd exposure in these two early life stages of mussels. In details, results indicated that Cd mainly induced immune and oxidative stresses in both D-shape larval and juvenile mussels via different pathways. In addition, the significant up-regulation of triosephosphate isomerase and metallothionein confirmed the enhanced energy demand and mobilized detoxification mechanism in D-shape larval mussels exposed to Cd. In juvenile mussels, Cd exposure also induced clear apoptosis. Overall, this work suggests that Cd is a potential immune toxicant to mussel M. galloprovincialis at early life stages. (C) 2016 Elsevier Ltd. All rights reserved

Kinetic modeling of pH-dependent antimony (V) sorption and transport in iron oxide-coated sand

Understanding the mechanisms and kinetics controlling the retention and transport of antimony (Sb) is prerequisite for evaluating the risk of groundwater contamination by the toxic element. In this study, kinetic batch and saturated miscible displacement experiments were performed to investigate effects of protonation-deprotonation reactions on sorption-desorption and transport of Sb(V) in iron oxide-coated sand (IOCS). Results clearly demonstrated that Sb(V) sorption was highly nonlinear and time dependent, where both sorption capacity and kinetic rates decreased with increasing solution pH. Breakthrough curves (BTCs) obtained at different solution pH exhibited that mobility of Sb(V) were higher under neutral to alkaline condition than under acidic condition. Because of the nonlinear and non-equilibrium nature of Sb(V) retention and transport, multi-reaction models (MRM) with equilibrium and kinetic sorption expressions were utilized successfully to simulate the experiment data. Equilibrium distribution coefficient (K-e) and reversible kinetic retention parameters (k(1) and k(2)) of both kinetic sorption and transport experiment showed marked decrease as pH increased from 4.0 to 7.5. Surface complexation is suggested as the dominant mechanism for the observed pH-dependent phenomena, which need to be incorporated into the kinetic models to accurately simulate the reactive transport of Sb(V) in vadose zone and aquifers. (C) 2015 Published by Elsevier Ltd

New technologies for examining neuronal ensembles in drug addiction and fear

Correlational data suggest that learned associations are encoded within neuronal ensembles. However, it has been difficult to prove that neuronal ensembles mediate learned behaviours because traditional pharmacological and lesion methods, and even newer cell type-specific methods, affect both activated and non-activated neurons. Additionally, previous studies on synaptic and molecular alterations induced by learning did not distinguish between behaviourally activated and non-activated neurons. Here, we describe three new approaches—Daun02 inactivation, FACS sorting of activated neurons and c-fos-GFP transgenic rats — that have been used to selectively target and study activated neuronal ensembles in models of conditioned drug effects and relapse. We also describe two new tools — c-fos-tTA mice and inactivation of CREB-overexpressing neurons — that have been used to study the role of neuronal ensembles in conditioned fear

Study on Closed-set Speaker Identification Based on Biomimetic Pattern Recognition

In this paper, a new classifier of speaker identification has been proposed, which is based on Biomimetic pattern recognition (BPR). Distinguished from traditional speaker recognition methods, such as DWT, HMM, GMM, SVM and so on, the proposed classifier is constructed by some finite sub-space which is reasonable covering of the points in high dimensional space according to distributing characteristic of speech feature points. It has been used in the system of speaker identification. Experiment results show that better effect could be obtained especially with lesser samples. Furthermore, the proposed classifier employs a much simpler modeling structure as compared to the GMM. In addition, the basic idea "cognition" of Biomimetic pattern recognition (BPR) results in no requirement of retraining the old system for enrolling new speakers

Responses of streamflow to climate change in the northern slope of Tianshan Mountains in Xinjiang: A case study of the Toutun River basin

A case study on the responses of streamflow to climate change in the Toutun River basin was carried out based on data analysis of streamflow, precipitation, and temperatures during the past 50 years. Temporal series of the streamflow change in the Toutun River basin was analyzed and tested using the Mann-Kendall nonparametric test. Results revealed that the annual runoff of the Toutun River had been in a monotonic decreasing trend for the past 50 years. Compared with the 1950s and 1960s, the annual runoff in the 1990s decreased by 4.0x10(5) m(3) and 7.2 x 10(5) m(3). The precipitation did not show monotonic trend during the past 50 years, but the annual temperature increased by 1.121 degrees C since the 1950s. Further data analysis indicated that the monthly runoff of the Toutun River decreased significantly from August to October, with precipitation displaying the similar pattern of seasonal change. Analysis suggests that the reduction of streamflow in the Toutun River basin is possibly caused by the seasonal change of precipitation, especially the precipitation reduction in summer, and temperature increases

A theoretical model for predicting the spatial distribution of gas hydrate dissociation under the combination of depressurization and heating without the discontinuous interface assumption

Spatial distribution of gas hydrate dissociation is essential in analyzing gas recovery and related potential hazards. This work develops a 1D model for predicting the spatial distribution of gas hydrate dissociation under the combination of depressurization and heating in the clay-silty sediments. Without assuming a discontinuous interface and a sudden decrease of pressure, the sediment is divided into a dissociated zone, a dissociating zone, and an undissociated zone. The dissociating zone is further separated into a heating subzone and a non-heating subzone. This work finds that (i) the thicknesses of the dissociating zone and the heating subzone as well as the propagation distance of the hydrate dissociation front are all linear with the square root of time, and the square root of hydrate dissociation time at any location is also linear with the distance between the location and the production well; (ii) the expansion velocity of the dissociating zone is about ninety times faster than that of the heating subzone, and a higher absolute permeability causes a faster expansion velocity of the dissociating zone, but barely affects the expansion velocity of the heating subzone; and (iii) the thickness of the heating subzone is less than 5% of the thickness of the dissociating zone in the latter stage of the hydrate dissociation process. (C) 2015 Elsevier B.V. All rights reserved

HOW ACCENTUATION INFLUENCES SEMANTIC SHORT-TERM MEMORY REPRESENTATIONS DURING ON-LINE SPEECH PROCESSING: AN EVENT-RELATED POTENTIAL STUDY

In the present study, the ERP (event-related brain potentials) technique was used to investigate how accentuation influences the semantic short-term memory representations during on-line speech processing, and how this accentuation effect interacts with the distance of accentuation in the speech signal. Chinese spoken sentences were used as stimuli. The sentences included two critical words: Noun1 and Noun2, with the ERP time-locked to Noun2. During sentence comprehension, when the listener hears Noun2, he needs to retrieve Noun1 from the working memory and integrate it with Noun2. We manipulated the (de-)accentuation of Noun1 and the semantic relationship between Noun1 and Noun2 by changing Noun1 in the sentence context. Moreover, we manipulated the distance of accentuation (distance between Noun1 and Noun2) by changing the syntactic structure of the sentences. The results revealed a significant main effect of semantic relatedness, indicating that the low semantic relatedness condition elicited a larger N400 than the high semantic relatedness condition. Importantly, there was a significant two-way interaction between semantic relatedness and accentuation and a significant three-way interaction between semantic relatedness, accentuation, and distance. Further analysis demonstrated that, the semantic relatedness effect was modulated by accentuation in the long-distance sentences, but not in the short-distance sentences. That is, in the long-distance sentences, the semantic relatedness effect reached significance only when the to-be-integrated expression in the preceding sentence context was accented; however, in the short-distance sentences, the semantic relatedness effects reached significance regardless of the presence or absence of accentuation. The results indicated that, during on-line speech processing, accentuation can enhance the corresponding information's semantic short-term memory representation, and that the effect of accentuation on semantic short-term memory is somewhat flexible and shows up only when the words in the speech signal were far apart. (C) 2011 IBRO. Published by Elsevier Ltd. All rights reserved