Non-linear excitations in 1D correlated insulators

In this work we investigate charge transport in one-dimensional (1D) insulators via semi-classical and perturbative renormalization group (RG) methods. We consider the problem of electron-electron, electron-phonon and electron-two-level system interactions. We show that non-linear collective modes such as polarons and solitons are reponsible for transport. We find a new excitation in the Mott insulator: the polaronic soliton. We discuss the differences between band and Mott insulators in terms of their spin spectrum and obtain the charge and spin gaps in each one of these systems. We show that electron-electron interactions provide strong renormalizations of the energy scales in the problem.Comment: 29 page

Analyst Coverage And Audit Efforts: Empirical Approach To Audit Hours

This study investigates the effect of financial analyst coverage on audit efforts by examining the association between the number of analyst followings and audit hours. Existing literatures report that there are inconsistent results between analyst coverage and audit efforts, and most studies used audit fee as a proxy for audit efforts. However, audit fee may cause measurement error. We consider that audit hour is a better proxy for measuring audit efforts than audit fee because practically auditors are less likely to charge extra audit fee for their additional efforts in competitive audit market. Also, after audit engagement contract, the amount of audit fee is almost fixed. Thus, it cannot reflect variable auditors’ decision whether inputting additional efforts or not during audit service. Intuitively, audit hours are more accurate measure of audit efforts as long as it indicates how much hours auditors work. For the above reasons, we use unique dataset of audit hours in Korea. We find that analyst coverage is positively associated with audit hour. This means auditors make more efforts on their audit service in case of greater analyst following, and they crucially consider reputational damage from audit failure when they provide audit services to their clients with great analyst following. Next, we still observe positive relation in both pre and post global financial crisis periods. Lastly, we find that BIG4 auditors are more concerned about reputational loss than Non-Big4 in case of greater analyst following

Is Contract Farming More Profitable and Efficient Than Non-Contract Farming-A Survey Study of Rice Farms In Taiwan

Trade liberalization and globalization has modernized the food retail sector in Taiwan, affecting consumers, producers and trade patterns. These changes have placed significant pressures on farmers and processors including more stringent quality control and product varieties. The government has launched a rice production-marketing contract program in 2005 to assist rice farmers and the agro-business sector to work together as partners. The minimum scale for each contract is 50 hectares of adjacent rice paddies with 50 participants including rice farmers, seedling providers, millers and marketing agents. In order to evaluate the outcome of this program, a survey is conducted in the summer of 2005 after the first (spring) crop is harvested. Information of price and value of output and major variable and fixed inputs are collected along with characteristics of the farmers and farms. The survey results show that the average revenue of a contract farm is about 11 percent higher than an average non-contract farm. The per hectare cost of production in a contract farm is about 13 percent lower and as a result the average profit margin under contract is more than 50 percent above those without contract. A swtiching regression profit frontier model is adopted to further investigate their efficiency performance. The result indicates that an average contract farms is 20 percent more efficient than an average non-contract farm in a comparable operating environment. The result also suggests that although contract farming has potential to improve the profit of smallholders, it is not a sufficient condition for such improvement.Land Economics/Use,

Jakość środowiska, korupcja i rozwój przemysłu: perspektywa globalna

This paper investigates the causal relationship between environmental quality and corruption for 129 countries, using the panel cointegration and panel-based error correction models for the period 2002-2015. In the paper, we use EPI, EHI, and EVI to represent environmental quality, which are more reasonable and comprehensive. We further take industry growth into consideration and investigate its impact on environmental quality. Our results corroborate that there exists a long-term equilibrium cointegrated relationship among the variables, both of corruption and industry growth have a negative effect on environmental quality and the corruption can seriously decrease environmental quality in the long term, while industry growth weakens environmental quality no matter in the short or long run.W artykule zbadano związek przyczynowy między jakością środowiska a korupcją w 129 krajach, wykorzystując modele kointegracji panelowej i panelowej korekcji błędów za lata 2002-2015. W pracy używamy EPI, EHI i EVI do wyznaczania jakości środowiska, które wydają się najbardziej sensowne i wszechstronne. Ponadto bierzemy pod uwagę rozwój branży i badamy jego wpływ na jakość środowiska. Nasze wyniki potwierdzają, że istnieje długoterminowa stabilna skointegorowana relacja pomiędzy zmiennymi, zarówno korupcja, jak i rozwój przemysłu mają negatywny wpływ na jakość środowiska, a korupcja może poważnie obniżyć jakość środowiska w dłuższej perspektywie, podczas gdy wzrost przemysłu osłabia jakość środowiska zarówno w krótkim, jak i długim okresie

Hafnium oxide-based ferroelectric thin-film transistor with a-InGaZnO channel fabricated at temperatures \u3c= 350°C

HfO2-based ferroelectric materials integrated with oxide-based thin-film transistors have been considered as potential candidates for back-end-of-line compatible ferroelectric field-effect transistors, which can be vertically stacked on silicon CMOS circuits to realize high-density neural network applications. However, the formation of ferroelectric orthorhombic phase in HfO2-based materials usually requires an annealing temperature of 400°C or higher. In this work, ferroelectric thin-film transistors (Fe-TFTs) were developed by monolithically integrating HfZrO2 (HZO) ferroelectric capacitors with amorphous indium-gallium-zinc oxide (a-IGZO) TFTs at a maximum processing temperature of 350°C on a glass substrate. A butterfly-shaped C-V curve was clearly observed in the low-temperature annealed metal-HZO-metal capacitor, indicating the formation of ferroelectricity in the HZO layer, as shown in Fig. 1. The positive and negative coercive voltages were 3 V and -2.4 V, respectively. The dielectric constant was 20.65. The field-effect mobility, threshold voltage, subthreshold swing and on/off current ratio of the a-IGZO TFT extracted from the transfer characteristics shown in Fig. 2 were 6.15 cm2V-1s-1, 1.5 V, 0.1 V/dec and 4.3´107, respectively. Fig. 3 shows the transfer hysteresis curves of the low-temperature Fe-TFTs in a metal-ferroelectric-metal-insulator-semiconductor configuration. The Fe-TFTs exhibited large hysteresis memory windows of 2.8 V and 3.8 V when the area ratios between ferroelectric capacitors and gate insulators (AFE / ADE) were 1/8 and 1/12, respectively. The result shows a great potential for back-end-of-line compatible memory applications. Please click Download on the upper right corner to see the full abstract

Genetic copy number variants in sib pairs both affected with schizophrenia

<p>Abstract</p> <p>Background</p> <p>Schizophrenia is a complex disorder with involvement of multiple genes.</p> <p>Methods</p> <p>In this study, genome-wide screening for DNA copy-number variations (CNVs) was conducted for ten pairs, a total of 20 cases, of affected siblings using oligonucleotide array-based CGH.</p> <p>Results</p> <p>We found negative symptoms were significantly more severe (p < 0.05) in the subgroup that harbored more genetic imbalance (n ≧ 13, n = number of CNV-disrupted genes) as compared with the subgroup with fewer CNVs (n ≦ 6), indicating that the degree of genetic imbalance may influence the severity of the negative symptoms of schizophrenia. Four central nervous system (CNS) related genes including CCAAT/enhancer binding protein, delta (<it>CEBPD</it>, 8q11.21), retinoid × receptor, alpha (<it>RXRA</it>, 9q34.2), LIM homeobox protein 5 (<it>LHX5</it>, 12q24.13) and serine/threonine kinase 11 (<it>STK11</it>, 19p13.3) are recurrently (incidence ≧ 16.7%) disrupted by CNVs. Two genes, <it>PVR </it>(poliovirus receptor) and <it>BU678720</it>, are concordantly deleted in one and two, respectively, pairs of co-affected siblings. However, we did not find a significant association of this <it>BU678720 </it>deletion and schizophrenia in a large case-control sample.</p> <p>Conclusions</p> <p>We conclude that the high genetic loading of CNVs may be the underlying cause of negative symptoms of schizophrenia, and the CNS-related genes revealed by this study warrant further investigation.</p

Exploring Online Repeat Purchase Intentions: The Role of Habit

By focusing on online stores, this study investigates the repeat purchase intention of experienced online buyers. Prior research on online behavior continuance models perceived usefulness, trust, satisfaction, and perceived value as the major determinants of continued adoption or loyalty, overlooking the important role of habit. Building on previous work in other disciplines, we define habit in the context of online shopping as the extent to which buyers tend to shop online automatically because of learning. Using recent work on the continued usage of IS (IS continuance) and repeat purchase, we have developed a model suggesting that repeat purchase intention is not only a consequence of trust and switching cost, but also of habit. In particular, in our research model, we propose that online shopping habit moderate the influence of trust such that its importance in determining repeat purchase intention decreases as the online shopping behavior takes on a more habitual nature. Integrating prior research on habit, IS continuance, and repeat purchase further, we suggest how antecedents of repeat purchase intention relate to drivers of habitualization. Data collected from 462 of Yahoo!Kimo shopping center’s customers provide strong support for the research model. Results indicate that higher level of habit deflated trust’s effect on repeat purchase intention. The data also show that satisfaction and familiarity are key to habit formation and thus relevant in the context of online repeat purchase