Thermal rectification in asymmetric U-shaped graphene flakes

In this paper, we study the thermal rectification in asymmetric U-shaped graphene flakes by using nonequilibrium molecular dynamics simulations. The graphene flakes are composed by a beam and two arms. It is found that the heat flux runs preferentially from the wide arm to the narrow arm which indicates a strong rectification effect. The dependence of the rectification ratio upon the heat flux, the length and the width of the beam, the length and width of the two arms are studied. The result suggests a possible route to manage heat dissipation in U-shaped graphene based nanoelectronic devices.Comment: 3 pages, 4 figure

Heat conduction in graphene flakes with inhomogeneous mass interface

Using nonequilibrium molecular dynamics simulations, we study the heat conduction in graphene flakes composed by two regions. One region is mass-loaded and the other one is intact. It is found that the mass interface between the two regions greatly decreases the thermal conductivity, but it would not bring thermal rectification effect. The dependence of thermal conductivity upon the heat flux and the mass difference ratio are studied to confirm the generality of the result. The interfacial scattering of solitons is studied to explain the absence of rectification effect.Comment: 5 pages, 4 figure

A 100-Element MODFET Grid Amplifier

A 100-element quasi-optical amplifier is presented. The active devices are custom-fabricated modulation-doped field-effect transistors (MODFETs). Common-mode oscillations were suppressed using resistors in the input gate leads. The grid has 9 dB of gain at 10.1 GHz. The 3-dB bandwidth is 1.2 GHz. We present a model for the gain of the grid versus frequency and compare measurement with theory

Genome-wide association study of electrocardiographic and heart rate variability traits: the Framingham Heart Study

BACKGROUND: Heritable electrocardiographic (ECG) and heart rate variability (HRV) measures, reflecting pacemaking, conduction, repolarization and autonomic function in the heart have been associated with risks for cardiac arrhythmias. Whereas several rare monogenic conditions with extreme phenotypes have been noted, few common genetic factors contributing to interindividual variability in ECG and HRV measures have been identified. We report the results of a community-based genomewide association study of six ECG and HRV intermediate traits. METHODS: Genotyping using Affymetrix 100K GeneChip was conducted on 1345 related Framingham Heart Study Original and Offspring cohort participants. We analyzed 1175 Original and Offspring participants with ECG data (mean age 52 years, 52% women) and 548 Offspring participants with HRV data (mean age 48 years, 51% women), in relation to 70,987 SNPs with minor allele frequency ≥ 0.10, call rate ≥ 80%, Hardy-Weinberg p-value ≥ 0.001. We used generalized estimating equations to test association of SNP alleles with multivariable-adjusted residuals for QT, RR, and PR intervals, the ratio of low frequency to high frequency power (LF/HFP), total power (TP) and the standard deviation of normal RR intervals (SDNN). RESULTS: Associations at p < 10-3 were found for 117 (QT), 105 (RR), 111 (PR), 102 (LF/HF), 121 (TP), and 102 (SDNN) SNPs. Several common variants in NOS1AP (4 SNPs with p-values < 10-3; lowest p-value, rs6683968, p = 1 × 10-4) were associated with adjusted QT residuals, consistent with our previously reported finding for NOS1AP in an unrelated sample of FHS Offspring and other cohorts. All results are publicly available at NCBI's dbGaP at. CONCLUSION: In the community-based Framingham Heart Study none of the ECG and HRV results individually attained genomewide significance. However, the presence of bona fide QT-associated SNPs among the top 117 results for QT duration supports the importance of efforts to validate top results from the reported scans. Finding genetic variants associated with ECG and HRV quantitative traits may identify novel genes and pathways implicated in arrhythmogenesis and allow for improved recognition of individuals at high risk for arrhythmias in the general population.National Institutes of Health (K23 N01-HC25195); Doris Duke Charitable Foundation Clinical Scientist Developement Award; Pfizer; National Institutes of Health National Center for Research Resources Shared Instrumentation grant (1S10RR163736-01A1

Gain and Stability Models for HBT Grid Amplifiers

A 16-element heterojunction bipolar transistor (HBT) grid amplifier has been fabricated with a peak gain of 11 dB at 9.9 GHz with a 3-dB bandwidth of 350 MHz. We report a gain analysis model for the grid and give a comparison of the measurement and theory. The measured patterns show the evidence of a common-mode oscillation. A stability model for the common-mode oscillation is developed. Based on the stability model, a lumped capacitor gives suitable phase shift of the circular function, thus stabilizing the grid. A second 18-element grid was fabricated, using this theory, with improved stability

Is There Transparency In Auditor Change Disclosures?

In this paper, we examine the reasons disclosed in a small representative sample of Form 8-Ks for switching auditors. We classify auditor switches in terms of changes from big-4 to other big-4, big-4 to non-big-4, non-big-4 to big-4 and non-big-4 to non-big-4. Our primary objective is to assess compliance with the required disclosures for auditor changes and to reflect on the implications for corporate governance. This line of research is important in light of the requirements of SEC Regulation S-K 304 and recent calls for greater transparency in financial reporting, particularly after Sarbanes-Oxley.&nbsp; Our research shows that companies use boilerplate language and adopt a check-the-box approach to compliance with Regulation S-K 304. Contrary to the spirit and intent of corporate governance, their disclosures generally lack transparency and offer little or no insight into the underlying reasons for auditor changes. One of the clearest patterns is that several auditor changes are preceded by such reportable events as going concern uncertainties and material internal control deficiencies that often lead to financial statement restatements. Even so, many companies are less than forthright in the language used to disclose such events. Thus, we conclude that the implied objective of auditor change regulations is not being fulfilled.&nbsp; In general, neither auditors nor clients appear to take the auditor change disclosure requirements seriously. It is vital that the PCAOB, SEC, and the audit committees take note of this weakness in auditor change regulation

Five Simple and Low Maintenance Investing Strategies: Seeking an Automated Investing System

The purpose of the paper is to examine five different investment strategies which are known to be easily implemented by ordinary investors: (1) S&amp;P 500 strategy, (2) No OTC &amp; No ADR (NoOtcAdr) strategy, (3) Warren Buffett’s stock market indicator-based strategy, (4) Federal Reserve Bank’s monetary policy-based strategy, and (5) Joel Greenblatt’s magic formula strategy. Among a large number of minimal maintenance strategies available, we investigate the efficacy of these five investment strategies because these strategies are extremely simple to implement and require little time commitment for investment research. Once they are set up, they will be maintenance free. Based on our findings and analysis, we propose a pair of options to retail investors, depending on their time commitment and risk tolerance level. Among five investment strategies, investors with high-risk tolerance may find merits in the Fed’s monetary policy-based strategy, whereas investors with low-risk tolerance may find Buffett’s stock market indicator-based strategy attractive. Keywords: Low maintenance investing strategies; Fed funds rate; Greenblatt’s magic formula; Sector rotation, Warren Buffett stock market indicator DOI: 10.7176/RJFA/11-2-01 Publication date: January 31st 202

An Application Of An Artificial Neural Network Investment System To Predict Takeover Targets

Artificial neural networks are a robust, effective complement to traditional statistical methods in financial applications. They can incorporate qualitative and quantitative information, and recognize underlying patterns and trends in large, complex data sets.  This paper applies a neural network model to identify potential acquisition targets. The model incorporates various factors based on acquisition theories suggested in the literature.  The resulting neural network model exhibits a highly successful prediction rate and a portfolio of predicted target stocks identified by the network substantially outperformed the market

An Examination Of The Current State Of Accounting Information Systems Education

This paper reviews several factors that drive the need for a closer examination of accounting information systems (AIS) education and provides an assessment of the current state of AIS education in the US. The assessment draws from two separate sets of guidelines for AIS education, published by the American Institute of Certified Public Accountants and Information Systems Audit and Control Association. These guidelines are used because they were developed by professionals in the field, with input from academics, and represent publicly available, coherent attempts to identify a body of AIS knowledge for accountants and auditors. We surveyed undergraduate and masters programs offered in all accounting departments with separate AACSB-accounting accreditation. Our survey found very few degree programs or concentrations in AIS as well as a considerable amount of diversity among existing programs.  Consistent with Christensen’s innovation dilemma (1997), we speculate that the traditional absence of a focused, coherent attempt to develop and promote accounting information systems as an academic discipline may be one of the critical factors that contributes to the slow diffusion of AIS programs in business school

Modeling and performance of a 100-element pHEMT grid amplifier

A 100-element hybrid grid amplifier has been fabricated, The active devices in the grid are custom-made pseudomorphic high electron mobility transistor (pHEMT) differential-pair chips. We present a model for gain analysis and compare measurements with theory. The grid includes stabilizing resistors in the gate. Measurements show the grid has a peak gain of 10 db when tuned for 10 GHz and a gain of 12 dB when tuned for 9 GHz. The maximum 3-dB bandwidth is 15% at 9 GHz. The minimum noise figure is 3 dB. The maximum saturated output power is 3.7 W, with a peak power-added efficiency of 12%. These results area significant improvement over previous grid amplifiers based on heterojunction bipolar transistors (HBT's)