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101.
Justin C Sanchez Deniz Erdogmus Miguel A L Nicolelis Johan Wessberg Jose C Principe 《IEEE transactions on neural systems and rehabilitation engineering》2005,13(2):213-219
We propose the use of optimized brain-machine interface (BMI) models for interpreting the spatial and temporal neural activity generated in motor tasks. In this study, a nonlinear dynamical neural network is trained to predict the hand position of primates from neural recordings in a reaching task paradigm. We first develop a method to reveal the role attributed by the model to the sampled motor, premotor, and parietal cortices in generating hand movements. Next, using the trained model weights, we derive a temporal sensitivity measure to asses how the model utilized the sampled cortices and neurons in real-time during BMI testing. 相似文献
102.
Behavioral, neuropsychological, and brain imaging research points to a dedicated system for processing number that is shared across development and across species. This foundational Approximate Number System (ANS) operates over multiple modalities, forming representations of the number of objects, sounds, or events in a scene. This system is imprecise and hence differs from exact counting. Evidence suggests that the resolution of the ANS, as specified by a Weber fraction, increases with age such that adults can discriminate numerosities that infants cannot. However, the Weber fraction has yet to be determined for participants of any age between 9 months and adulthood, leaving its developmental trajectory unclear. Here we identify the Weber fraction of the ANS in 3-, 4-, 5-, and 6-year-old children and in adults. We show that the resolution of this system continues to increase throughout childhood, with adultlike levels of acuity attained surprisingly late in development. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
103.
Harris Justin A.; Jones Megan L.; Bailey Glynis K.; Westbrook R. Frederick 《Canadian Metallurgical Quarterly》2000,26(2):174
Four experiments studied contextual control over rats' freezing to conditioned stimuli (CSs) that had been paired with shock and were then extinguished. In Experiment 1, rats were exposed to a CS A–shock and a CS B–shock pairing in Context C. CS A was then extinguished in Context A, and CS B in Context B. Freezing was renewed when each CS was presented in the context where the other CS had been extinguished. In Experiments 2–4, rats were exposed to a CS A–shock pairing in A and a CS B–shock pairing in B. They were then exposed to Context C where one, both, or neither of the CSs were extinguished, or where both CSs continued to be reinforced. On test, the rats froze more to CS A than to CS B in Context A, and more to CS B than to CS A in Context B, but only if the CSs had been extinguished. Thus, after extinction, rats use contexts to regulate retrieval not only of their memory for extinction, but also of their memory for the original conditioning episode. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
104.
Justin D. Talley 《Nuclear Engineering and Design》2010,240(5):1111-99
The present study develops an interfacial area transport equation applicable to an air-water horizontal bubbly flow, along which two types of horizontal elbows are installed as flow restrictions. Two sets of experiments are performed in a round glass tube of 50.3 mm inner diameter. Along the test section, a 90-degree elbow is installed at L/D = 206.6 from the two-phase mixture inlet and then a 45-degree elbow is installed at L/D = 353.5. In total, 15 different flow conditions in the bubbly flow regime for each of the two flow restriction experiments are studied. Detailed local two-phase flow parameters are acquired by a double-sensor conductivity probe at four different axial locations in the 90-degree experiment and three different axial locations in the 45-degree experiment. The effect of the elbows is found to be evident in the distribution of local parameters as well as in the development of interfacial structures. It is clear that the elbows make an effect on the bubble interactions resulting in significant changes to both the void fraction and interfacial area concentration. In the present analysis, the interfacial area transport equation is developed in one-dimensional form via area averaging. In the averaging process, characteristic non-uniform distributions of the flow parameters in horizontal two-phase flow are treated mathematically through a distribution parameter. The mechanistic models for the major bubble interaction phenomena developed in vertical flow analysis are employed in the present study. Furthermore, the change in pressure due to the minor loss of an elbow is taken into consideration by using a newly developed correlation analogous to Lockhart and Martinelli's. In total, 105 area-averaged data points are employed to benchmark the present model. The present model predicts the data relatively well with an average percent difference of approximately ±20%. 相似文献
105.
在电机控制系统中,设计者可通过周密分析获得理想的性能,即使开始看上去某些元件不合适.对于来自电流传感器的±5 V输出信号,则需要使用双电源(±12 V)的模数(A/D)转换器,TI公司推出的ADS7864型A/D转换器拥有同样效能,并给出了相关闭环电流互感器的应用. 相似文献
106.
互联网的存在,不仅能提升资讯,取得与双方间资讯交换的速度,更解决了资讯共享的瓶颈,因此所有的传统工业无不争先恐后的在互联网中探寻,希望能从中找到企业新一轮的竞争力。 相似文献
107.
Sean Poust James Piety Dr. Arren Bar‐Even Dr. Catherine Louw Prof. Dr. David Baker Prof. Dr. Jay D. Keasling Prof. Dr. Justin B. Siegel 《Chembiochem : a European journal of chemical biology》2015,16(13):1950-1954
An enzyme that catalyzes the formose reaction, termed “formolase”, was recently engineered through a combination of computational protein design and directed evolution. We have investigated the kinetic role of the computationally designed residues and further characterized the enzyme's product profile. Kinetic studies illustrated that the computationally designed mutations were synergistic in their contributions towards enhancing activity. Mass spectrometry revealed that the engineered enzyme produces two products of the formose reaction—dihydroxyacetone and glycolaldehyde—with the product profile dependent on the formaldehyde concentration. We further explored the effects of this product profile on the thermodynamics and yield of the overall carbon assimilation from the formolase pathway to help guide future efforts to engineer this pathway. 相似文献
108.
Solid acid polymer electrolytes (SAPE) were synthesised using polyvinyl alcohol, potassium iodide and sulphuric acid in different molar ratios by solution cast technique. The temperature dependent nature of electrical conductivity and the impedance of the polymer electrolytes were determined along with the associated activation energy. The electrical conductivity at room temperature was found to be strongly depended on the amorphous nature of the polymers and H2SO4 concentration. The ac (100 Hz to 10 MHz) and dc conductivities of the polymer electrolytes with different H2SO4 concentrations were analyzed. A maximum dc conductivity of 1.05 × 10−3 S cm−1 has been achieved at ambient temperature for electrolytes containing 5 M H2SO4. The frequency and temperature dependent dielectric and electrical modulus properties of the SAPE were studied. The charge transport in the present polymer electrolyte was obtained using Wagner's polarization technique, which demonstrated the charge transport to be mainly due to ions. Using these solid acid polymer electrolytes novel Zn/SAPE/MnO2 solid state batteries were fabricated and their discharge capacity was calculated. An open circuit voltage of 1.758 V was obtained for 5 M H2SO4 based Zn/SAPE/MnO2 battery. 相似文献
109.
<正>新西兰馆的主题是"自然之城:生活在天与地之间"。故事从一个凉棚说起。凉棚始于一条欢迎走廊。建筑设计师布莱尔(Blair)想让"参观者体验新西兰城市和大自然,进入展馆之后,可以沿着一条弯弯曲曲的斜坡,渐渐往上走。新西兰的风景、森林、海洋、山脉、城市和人……"最后,人们将会走上屋顶。正是在这里,布莱尔为景观设计师提供了一个大舞台。 相似文献
110.
Carmen Abate Dr. Justin Elenewski Mauro Niso Dr. Francesco Berardi Prof. Dr. Nicola Antonio Colabufo Prof. Dr. Amalia Azzariti Dr. Roberto Perrone Prof. Dr. Richard A. Glennon Prof. Dr. 《ChemMedChem》2010,5(2):268-273
Sigma‐2 (σ2) binding sites are an emerging target for anti‐neoplastic agents due to the strong apoptotic effect exhibited by σ2 agonists in vitro and the overexpression of these sites in tumor cells. Nonetheless, no σ2 receptor protein has been identified. Affinity chromatography using the high‐affinity σ2 ligand PB28 and human SK‐N‐SH neuroblastoma cells was previously utilized to identify σ2 ligand binding proteins, specifically histones H1, H2A, H2B, and H3.3a. To rationalize this finding, homology modeling and automated docking studies were employed to probe intermolecular interactions between PB28 and human nucleosomal proteins. These studies predicted interaction of PB28 with the H2A/H2B dimer at a series of sites previously found to be implicated in chromatin compaction and nucleosomal assembly. To experimentally verify this prediction, a competitive binding assay was performed on the reconstituted H2A/H2B dimer using [3H]PB28 as radioligand, and an IC50 value of 0.50 nM was determined for PB28 binding. In addition, [3H]PB28 was found to accumulate with up to a fivefold excess in nuclear fractions over cytosolic fractions of SK‐N‐SH and MCF7 cells, indicating that PB28 is capable of entering the nucleus to interact with histone proteins. In conjunction with computational results, these data suggest that PB28 may exert its cytotoxic effect through direct interaction with nuclear material. 相似文献