Rectifying characteristics, magnetic tunability, and photovoltaic response in La0.8Hf0.2MnO3/0.7 wt% Nb-SrTiO3 heteroepitaxial junctions

Heterojunctions composed of tetravalent cation-doped La 0.8Hf 0.2MnO 3 (LHMO) and 0.7 wt Nb-doped SrTiO 3 were fabricated using pulsed laser deposition method and investigated under different fields (electric, magnetic, and optic). The heterojunctions exhibited excellent rectifying behavior in a wide temperature range and significant magnetic field modulated properties. Prominent photovoltaic effect was also observed in the formed junctions. Special attention has been paid to the temperature dependence of the diffusion voltage (V d) and photovoltage (V oc). When temperature increased from 40 K to 300 K, V d decreased from 1.13 V to 0.16 V. It is notable that, under illumination of a light with λ = 532 nm, V oc dropped from 650 to 80 mV. No sudden change of V d and V oc was observed at the metal-insulator transition temperature, which is probably caused by the band structure of the LHMO. © 2012 American Institute of Physics.published_or_final_versio

Influences of leakage currents on the transport properties and photoelectric effects in heterojunctions composed of colossal magnetoresistance manganites and Nb-doped titanates

The effects of leakage currents were investigated for Pr 0.7Sr 0.3MnO 3/Nb-SrTiO 3 heterojunctions. It was found that small amounts of leakage currents could cause pronounced detriment to the rectifying properties but had very limited impacts on the barrier heights determined from the forward currents. Significant open circuit voltages V OC were observed when the highly rectified junctions were illuminated by a visible light with a wavelength of 532 nm. For the less rectified junctions, the leakage currents reduced V OC severely and resulted in an anomalous temperature dependence of V OC. Theories for semiconductor contacts were employed in order to discuss these results. © 2012 American Institute of Physics.published_or_final_versio

Electric currents induced step-like resistive jumps and negative differential resistance in thin films of Nd0.7Sr0.3MnO3

Electric-currents-induced emergent phenomena were found in microbridges of Nd 0.7Sr 0.3MnO 3. After the samples were processed by currents of high densities, a second metal-insulator transition appeared at low temperatures. This resistance peak was very sensitive to weak currents. More salient features were the step-like resistance jumps. At temperatures near these resistance steps, negative differential resistance was observed. Interfacial effects related to electrodes could be ruled out. These effects might be due to current-enhanced inhomogeneity. © 2012 American Institute of Physics.published_or_final_versio

Insolation triggered abrupt weakening of Atlantic circulation at the end of interglacials.

Abrupt cooling is observed at the end of interglacials in many paleoclimate records, but the mechanism responsible remains unclear. Using model simulations, we demonstrate that there exists a threshold in the level of astronomically induced insolation below which abrupt changes at the end of interglacials of the past 800,000 years occur. When decreasing insolation reaches the critical value, it triggers a strong, abrupt weakening of the Atlantic meridional overturning circulation and a cooler mean climate state accompanied by high-amplitude variations lasting for several thousand years. The mechanism involves sea ice feedbacks in the Nordic and Labrador Seas. The ubiquity of this threshold suggests its fundamental role in terminating the warm climate conditions at the end of interglacials

Differences between physical and human process simulation in geography: Empirical analysis of two cases

National Natural Science Foundation of China 41125005;Chinese Academy of Sciences KACX1-YW-1001Physical geography and human geography are the principal branches of the geographical sciences. Physical process simulation and human process simulation in geography are both quantitative methods used to recover past events and even to forecast events based on precisely determined parameters. There are four differences between physical process simulation and human process simulation in geography, which we summarize with two specific cases, one of which is about a typhoon's development and its precipitation, and the other of which is regarding the evolution of three industrial structures in China. The differences focus on four aspects: the main factors of the research framework; the knowledge background of the systematic analysis framework; the simulation data sources and quantitative method; and the core of the study object and the method of forecast application. As the human-land relationship is the key ideology of the man-land system, the relationship between the physical and human factors is becoming increasingly close at present. Physical process simulation and human process simulation in geography will exhibit crossing and blending in the future to reflect the various geographical phenomena better

Genetic loci mapping for ear axis weight using recombinant inbred line (RIL) population under different nitrogen regimes in maize

Ear axis weight (EAW) is one of the important agronomic traits in maize (Zea mays L.), related to yield. To understand its genetic basis, a recombinant inbred line (RIL) population, derived from the cross Mo17 × Huangzao4, was used for quantitative trait locus mapping (QTL) for EAW under high and low nitrogen (N) regimes. The results showed that a total of three QTLs were mapped on chromosomes 2 (two) and 4 (one) under the two N regimes, which could explain phenotypic variances from 4.76 to 7.12%. They were near to their linked markers, with mapping interval of 0.2 to 1.0 cM. The two loci on chromosome 2 (bin 2.09) made EAW increase due to positive additive effects, while the other locus on chromosome 4 (bin 4.08) made EAW decrease to some extent, owing to negative additive effects. These results are beneficial for understanding the genetic basis of KNE and developing marker-assisted selection in maize breeding project.Key words: Maize (Zea mays L.), ear axis weight, quantitative trait locus, recombinant inbred line, nitrogen

Human motion tracking based on complementary Kalman filter

Miniaturized Inertial Measurement Unit (IMU) has been widely used in many motion capturing applications. In order to overcome stability and noise problems of IMU, a lot of efforts have been made to develop appropriate data fusion method to obtain reliable orientation estimation from IMU data. This article presents a method which models the errors of orientation, gyroscope bias and magnetic disturbance, and compensate the errors of state variables with complementary Kalman filter in a body motion capture system. Experimental results have shown that the proposed method significantly reduces the accumulative orientation estimation errors

Prolonged membrane potential depolarization in cingulate pyramidal cells after digit amputation in adult rats

The anterior cingulate cortex (ACC) plays an important role in higher brain functions including learning, memory, and persistent pain. Long-term potentiation of excitatory synaptic transmission has been observed in the ACC after digit amputation, which might contribute to plastic changes associated with the phantom pain. Here we report a long-lasting membrane potential depolarization in ACC neurons of adult rats after digit amputation in vivo. Shortly after digit amputation of the hind paw, the membrane potential of intracellularly recorded ACC neurons quickly depolarized from ~-70 mV to ~-15 mV and then slowly repolarized. The duration of this amputation-induced depolarization was about 40 min. Intracellular staining revealed that these neurons were pyramidal neurons in the ACC. The depolarization is activity-dependent, since peripheral application of lidocaine significantly reduced it. Furthermore, the depolarization was significantly reduced by a NMDA receptor antagonist MK-801. Our results provide direct in vivo electrophysiological evidence that ACC pyramidal cells undergo rapid and prolonged depolarization after digit amputation, and the amputation-induced depolarization in ACC neurons might be associated with the synaptic mechanisms for phantom pain

A quantitative trait locus for the number of days from sowing to seedling emergence in maize

Quantitative trait locus (QTL) mapping provides useful information for breeding programs since it allows the estimation of genomic locations and genetic effects of chromosomal regions related to the expression of quantitative traits. The number of days from sowing to seedling emergence (NDSSE) is an important agronomic trait in a maize (Zea mays L.) breeding project which is related to yield. To determine its genetic basis, a recombinant inbred line (RIL) population and two nitrogen (N) regimes were used to detect the QTLs associated with NDSSE; as a result, one QTL was identified under high N regime, on chromosome 9, which could explain 6.20% of phenotypic variance and a decrease of 0.18 of NDSSE due to an additive effect. These results are beneficial for understanding the genetic basis of NDSSE in maize breeding project.Key words: Maize (Zea mays L.), quantitative trait locus, recombinant inbred line, nitrogen

Beat-to-beat ambulatory blood pressure estimation based on random forest

Ambulatory blood pressure is critical in predicting some major cardiovascular events; therefore, cuff-less and noninvasive beat-to-beat ambulatory blood pressure measure-ment is of great significance. Machine-learning methods have shown the potential to derive the relationship between physio-logical signal features and ABP. In this paper, we apply random forest method to systematically explorer the inherent connections between photoplethysmography signal, electrocardiogram signal and ambulatory blood pressure. To archive this goal, 18 features were extracted from PPG and ECG signals. Several models with most significant features as inputs and beat-to-beat ABP as outputs were trained and tested on data from the Multi-Parameter Intelligent Monitoring in Intensive Care II database. Results indicate that compared with the common pulse transit time method, the RF method gives a better performance for one-hour continuous estimation of diastolic blood pressure and systolic blood pressure under both the Association for the Advancement of Medical Instrumentation and British Hyper-tension Society standard