Information-geometric method for multiple neuronal spike data analysis

This dissertation explores a novel statistical technique—information geometric method for theory and its application in analysis of multiple neuronal spike data. The previous studies have indicated that information-geometric method provides a powerful tool of estimating neuronal interactions from observed spiking data. However, these studies were conducted based on simplified neural network structure, which has limitations in the real brain. We systematically extended the previous studies by using intensive mathematical analysis and numerical simulations of realistic and complex neural network. The studies show that information geometric approach provide robust estimation for the sum of the connection weights between neuronal pairs in a complex recurrent network, providing a way of investigating the underlying network structures from neuronal spike data.Alberta Innovates Technology Futures (SCH001),National Science Foundation(CRCNS-1010172),Alberta Innovates Health Solution

An Empirical Analysis on Cost Efficiency and Determinants of Commercial Banks in Hong Kong

This paper examines the cost efficiency of 35 commercial banks in Hong Kong over the period 2009 to 2014. By employing SFA method, the mean cost efficiency score of the sample commercial banks ranges from 88% to 97.66%. Meanwhile, the determinants of cost efficiency level are investigated, where Tobit regression model is utilized and the cost efficiency is adopted as dependent variable. Among the internal and external determinants, the GDP growth rate has a negative impact on Hong Kong commercial banks, while the net loan to total asset ratio is positively related to the cost efficiency level of the banks

C1q/tumor necrosis factor (TNF)-associated protein 6 (CTRP6) ameliorates the cognitive dysfunction induced by sevoflurane by activating AMPK/SIRT1 pathway in rats

Purpose: To evaluate the possible effects of C1q/tumor necrosis factor (TNF)-associated protein 6 (CTRP6) on postoperative cognitive dysfunction (POCD), including the potentially-related signaling pathway.Methods: Behavioral analysis and cognitive impairment were assessed in each group. Immunoblots were used to determine the level of CTRP6 following sevoflurane-induced nerve injury. Hippocampal neurons were identified using Nissl staining, while inflammatory response following neuronal injury was monitored by enzyme-linked immunosorbent assay (ELISA) and quantitative polymerase chain reaction (qPCR). The involvement of adenosine monophosphate-activated protein kinase (AMPK)/sirtuin 1 (SIRT1) pathway was determined using immunoblot.Results: CTRP6 alleviated sevoflurane-induced cognitive dysfunction in rats (p < 0.001). Moreover, CTRP6 reduced sevoflurane-induced nerve injury and inflammation in rats (p < 0.05).Conclusion: CTRP6 ameliorates sevoflurane-induced cognitive dysfunction by activating AMPK/SIRT1 pathway, thus offering a novel target for POCD treatment

Information-geometric measures estimate neural interactions during oscillatory brain states

Sherpa Romeo green journal: open accessThe characterization of functional network structures among multiple neurons is essential to understanding neural information processing .Information geometry (IG) ,a theory developed for investigating a space of probability distribution shas recently been applied to spike-train analys is and has provided robust estimations of neural interactions. Although neural firing in the equilibrium state is often assumed in these studies, in reality, neural activity is non-stationary. The brain exhibits various oscillations depending on cognitive demands or when an animal is asleep. Therefore, the investigation of the IG measures during oscillatory network states is important for testing how the IG method can be applied to real neural data. Using model networks of binary neurons or more realistic spiking neurons, we studied how the single-and pairwise-IG measures were influenced by oscillatory neural activity. Two genera loscillatory mechanisms, externally driven oscillations andi nternally induced oscillations, were considered. In both mechanisms, we found that the single-IG measure was linearly related to the magnitude of the external input, and that the pairwise-IG measure was linearly related to the sum of connection strengths between two neurons. We also observed that the pairwise-IG measure was not dependent on the oscillation frequency. These results are consistent with the previous findings that were obtained under the equilibrium conditions. Therefore, we demonstrate that the IG method provides useful insights into neural interactions under the oscillatory condition that can often be observed in the real brain.Ye

The feasibility of Sn, In, or Al doped ZnSb thin film as candidates for phase change material

The potentials of Sn, In, or Al doped ZnSb thin film as candidates for phase change materials have been studied in this paper. It was found that the Zn-Sb bonds were broken by the addition of the dopants and homopolar Zn-Zn bonds and other heteropolar bonds, such as Sn-Sb, In-Sb, and Al-Sb, were subsequently formed. The existence of homopolar Sn-Sn and In-In bonds in Zn₅₀Sb₃₆Sn₁₄ and Zn₄₁Sb₃₆In₂₃ films, but no any Al-Al bonds in Zn₃₅Sb₃₀Al₃₅ film, was confirmed. All these three amorphous films crystallize with the appearance of crystalline rhombohedral Sb phase, and Zn₃₅Sb₃₅Al₃₅ film even exhibits a second crystallization process where the crystalline AlSb phase is separated out. The Zn₃₅Sb₃₀Al₃₅ film exhibits a reversible phase change behavior with a larger Ea ( 4.7 eV), higher Tc (~ 245ᴼ C), better 10-yr data retention (~ 182ᴼ C), less incubation time (20 ns at 70 mW), and faster complete crystallization speed (45 ns at 70 mW). Moreover, Zn₃₅Sb₃₀Al₃₅ film shows the smaller root-mean-square (1.654 nm) and less change of the thickness between amorphous and crystalline state (7.5%), which are in favor of improving the reliability of phase change memory.This work was financially supported by the Natural Science Foundation of China (Grant Nos. 61306147, 61377061), the Public Project of Zhejiang Province (Grant No.2014C31146), the Young Leaders of academic climbing project of the Education Department of Zhejiang Province (pd2013092), the Natural Science Foundation of Zhejiang Province (Grant No. LQ15F040002), the Scientific Research Foundation of Graduate School of Ningbo University, and sponsored by K. C. Wong Magna Fund in Ningbo University

Enhanced thermal stability and electrical behavior of Zn-doped Sb2Te films for phase change memory application

Zn-doped Sb₂Te films are proposed to present the feasibility for phase-change memory application. Zn atoms are found to significantly increase crystallization temperature of Zn x (Sb₂Te)1−x films and be almost linearly with the wide range of Zn-doping concentration from x = 0 to 29.67 at.%. Crystalline resistances are enhanced by Zn-doping, while keeping the large amorphous/crystalline resistance ratio almost constant at ∼10⁵. Especially, the Zn 26.07 (Sb₂Te)73.93 and Zn 29.67 (Sb₂Te)70.33 films exhibit a larger resistance change, faster crystallization speed, and better thermal stability due to the formation of amorphous Zn-Sb and Zn-Te phases as well as uniform distribution of Sb₂Te crystalline grains

Improved phase-change characteristics of Zn-doped amorphous Sb₇Te₃ films for high-speed and low-power phase change memory

The superior performance of Zn-doped Sb₇Te₃ films might be favorable for the application in phase change memory. It was found that Zn dopants were able to suppress phase separation and form single stable Sb2Te crystal grain, diminish the grain size, and enhance the amorphous thermal stability of Sb₇Te₃ film. Especially, Zn 30.19(Sb₇Te₃)69.81 film has higher crystallization temperature (∼258 °C), larger crystallization activation energy (∼4.15 eV), better data retention (∼170.6 °C for 10 yr), wider band gap (∼0.73 eV), and higher crystalline resistance. The minimum times for crystallization of Zn 30.19(Sb₇Te₃)69.81 were revealed to be as short as ∼10 ns at a given proper laser power of 70 mW.This work was financially supported by the International Science & Technology Cooperation Program of China (Grant No. 2011DFA12040), the National Program on Key Basic Research Project (973 Program) (Grant No. 2012CB722703), the Natural Science Foundation of China (Grant Nos. 61008041 and 60978058), the CAS Special Grant for Postgraduate Research, Innovation and Practice, the Program for Innovative Research Team of Ningbo city (Grant No. 2009B21007), and sponsored by K. C. Wong Magna Fund in Ningbo University

Full Characterization of the Bunch-Compressor Dipoles for FLUTE

The Ferninfrarot Linac- Und Test-Experiment (FLUTE) is a KIT-operated linac-based test facility for accelerator research and development as well as a compact, ultra-broadband and short-pulse terahertz (THz) source. As a key component of FLUTE, the bunch compressor (chicane) consisting of four specially designed dipoles will be used to compress the 40-50 MeV electron bunches after the linac down to single fs bunch length. The maximum vertical magnetic field of the dipoles reach 0.22 T, with an effective length of 200 mm. The good field region is ±40 mm and ±10.5 mm in the horizontal and vertical direction, respectively. The latest measurement results of the dipoles in terms of field homogeneity, excitation and field reproducibility within the good field regions will be reported, which meet the predefined specifications. The measured 3D magnetic field distributions have been used to perform beam dynamics simulations of the bunch compressor. Effects of the real field properties on the beam dynamics, which are different from that of the ASTRA built-in dipole field, will be discussed

Reviewing the potential of bio-hydrogen production by fermentation

Hydrogen is a common reactant in the petro-chemical industry and moreover recognized as a potential fuel within the next 20 years. The production of hydrogen from biomass and carbohydrate feedstock, though undoubtedly desirable and favored, is still at the level of laboratory or pilot scale. The present work reviews the current researched pathways. Different types of carbohydrates, and waste biomass are identified as feedstock for the fermentative bio-hydrogen production. Although all techniques suffer from drawbacks of a low H2 yield and the production of a liquid waste stream rich in VFAs that needs further treatment, the technical advances foster the commercial utilization. Bacterial strains capable of high hydrogen yield are assessed, together with advanced techniques of co-culture fermentation and metabolic engineering. Residual VFAs can be converted. The review provides an insight on how fermentation can be conducted for a wide spectrum of feedstock and how fermentation effluent can be valorized by integrating fermentation with other systems, leading to an improved industrial potential of the technique. To boost the fermentation potential, additional research should firstly target its demonstration on pilot or industrial scale to prove the process efficiency, production costs and method reliability. It should secondly focus on optimizing the micro-organism functionality, and should finally develop and demonstrate a viable valorization of the residual VFA-rich waste streams