Miracle-dz/UniFAR-FTUs huggingface dataset:
Puits et boîtes quantiques de GaN/AlN pour les applications en optoélectronique à 1,55 µm

Les nanostructures de puits ou boites quantiques de GaN/AlN presentent des potentialites tres interessantes pour les applications aux composants optoelectroniques telecoms. Ceci tient a la forte discontinuite en bande de conduction qui permet d'observer des absorptions intrabandes entre niveaux electroniques confines dans la gamme de longueurs d'onde de 1,3 a 1,55 µm. Les echantillons etudies durant la these ont ete fabriques par epitaxie par jets moleculaires avec pour source d'azote soit de l'ammoniac (CRHEA) soit un plasma d'azote (CEA). Les echantillons ont ete caracterises par differentes techniques structurales (RBS, TEM, diffraction de rayons-X) ainsi que par des mesures optiques: spectroscopie de transmission a transformee de Fourier, d'absorption photo-induite et de photoluminescence. Nous montrons que les puits quantiques GaN/AlN presentent une absorption intersousbandes intenses a temperature ambiante et que celle-ci est ajustable entre 1,3 et 2,1 µm en fonction de l'epaisseur du puits GaN (4 a 10 monocouches). Nous observons aussi que le champ interne conjugue aux rugosites d'interfaces conduit a une forte localisation des porteurs dans le plan des couches a temperature ambiante. L'absorption des puits dopes est systematiquement decalee a haute energie par rapport aux puits non dopes. Nous interpretons ce decalage comme la consequence des effets a N-corps domines par l'interaction d'echange. Nous discutons enfin les resultats sur un premier dispositif de photo-detection intersousbandes a puits quantiques GaN. Nous rapportons aussi les resultats originaux que nous avons obtenus sur la spectroscopie intrabande du confinement electronique dans les boites quantiques auto-organisees de GaN/AlN. Nos resultats montrent la presence d'absorption intrabandes lies au confinement vertical des electrons aux longueurs d'onde dans la gamme 2,4-1,2 µm. Les transitions fondamentales s-px regies par le confinement dans le plan sont observees a plus grande longueur d'onde. Nous montrons enfin qu'en jouant sur le champ interne et en reduisant la taille des ilots, l'absorption intrabande s-pz est aux longueurs d'onde telecoms pour des boites de hauteur 1,5 a 2 nm.
Determinação da atividade antioxidante e do teor total de polifenol em amostras de chá de ervas comercializadas em sachets Determination of total antioxidant activity and total content of polyphenols in samples of tea leaves marketed in bags

objective: Tea leaves are traditionally used in folk medicine in many regions of Brazil. They contain antioxidant compounds that can protect against oxidative stress and their regular intake have been associated with decreased of cholesterol levels, blood pressure and, thereby, with the lowered risk of coronary heart disease. The objective of this study was to determine the total antioxidant capacity, the total polyphenols content, scavenging of H2O2 and presence of other groups of antioxidant compounds in 43 tea samples packed in bags. methods: The CUPRAC method (cupric ion reducing antioxidant capacity) was used to quantify the total antioxidant capacity. The polyphenols content was performed using the Folin-Ciocalteu reagent. The scavenging assay was based on the consumption of H2O2 after addition of tea; the presence of flavonoids, carotenes and catechins was evaluated by paper chromatography. results: The total antioxidant capacity found in tea samples followed the order: chamomile > mint > carqueja > balm > boldo > green > mate > black > white > fennel. For total polyphenol content the order was: white > mint > black > matte > boldo > green > chamomile > carqueja > balm > fennel. The differences found in the samples from the same kind of tea can be attributed to the harvest season, soil type, planting location, climate differences and from the parts of the vegetal material used in the preparation of the tea bags. Conclusion: All samples analyzed presented antioxidant activity and ability to scavenge H2O2. It was not possible to detect flavonoids, carotenes and catechins in only one sample.
The Possibilities of Adopting IAS/IFRS in Vietnam: An Analysis

It is universally acknowledged that the matter of adoption and its similar process (harmonisation or convergence) has provoked extensively heated debate in the accounting literature, both from advocates and from opponents. Nonetheless, the accounting literature lacks research into the field of Vietnamese accounting, in general, and the nature of Vietnamese accounting systems as well as Vietnamese Accounting Standards (VAS), in particular. This paper’s in-depth critical analysis looks at the possibility of adopting IAS/IFRS in Vietnam. Specifically, this paper considers the factors affecting the adoption of IAS/IFRS by Vietnam, and the arguments for and against adoption of IAS/IFRS which is valuable for considering IAS/IFRS within the Vietnamese accounting milieu.
Informed Momentum Trading versus Uninformed 'Naive' Investors Strategies

We construct a zero-net-worth uninformed "naive investor" who uses a random portfolio allocation strategy. We then compare the returns of the momentum strategist to the return distribution of naive investors. For this purpose we reward momentum profits relative to the return percentiles of the naive investors with scores that are symmetric around the median. The score function thus constructed is invariant and robust to risk factor models. We find that the average scores of the momentum strategies are close to zero (the score of the median) and statistically insignificant over the sample period between 1926 and 2005, various sub-sample periods including the periods examined in Jegadeesh and Titman (1993 and 2001). The findings are robust with respect to sampling or period-specific effects, tightened score intervals, and the imposition of maximum-weight restrictions on the naive strategies to mitigate market friction considerations.
The treatment technology of wastewater by high efficient hydrolysis-acidogenosis of anerobic baffled reaction (ABR).

The anerobic baffled reaction, a high efficient hydrolysis-acidogenosis technology treating wastewater was put forward. Through hydrolazical measures and pH value control, the swift water whirlpool was realized in the hydrolysis-acidogenosis system to improve mass transfer speed and pH value condition in the system to enhance activity of microorganism in the primary studies. As a result, the removal rate of COD was enhanced remarkably. The result of the experiment showed that in the COD concentration range of 450~900mg/L, the removal rate of soluble COD was 40%4%.
Contribution to the Analysis and Measurement of Bank Insolvency

The study of bank insolvency is of fundamental importance to the economy. Two basic justifications for it lie in the fact that without stability in the banking system monetary stability cannot be achieved, not to mention the high cost of banking crises for society as a whole. Greater financial instability in the last years and the new spate of banking crises in developed and developing countries have generated renewed interest in the subject. This article seeks to put forward a theoretical model capable of identifying the main aspects of bank insolvency in order to foster greater understanding of the issue and the implantation of more effective preventive measures.
A Descriptive Study of Factors Associated with the Internal Audit Function Having an Impact: Comparisons between Organizations in a Developed and an Emerging Economy

An internal audit function (IAF) should positively impact financial reporting and governance, and add value to its organization. We provide evidence on IAF factors (i.e., characteristics, activities, work areas) associated with these types of impact and whether these factors, and their influence on various impacts, differ between a developed and an emerging economy (i.e., US, Turkey). Factors positively associated with financial reporting in the US are assurance activities, control work, and competence; in Turkey, significant factors are governance work and competence. For governance, we find that the factors positively associated with it in the US include assurance activities, governance work, and competence; in Turkey the significant factors are governance work and competence. In the US, assurance activities are negatively associated with adding value, while consulting activities, risk work, and control work are positively associated with this measure. In Turkey, only risk work and control work are positively associated with adding value. Finally, several measures of IAF objectivity are not associated with any of our impact measures.
Why does Shareholder Protection Matter for Abnormal Returns after Reported Insider Purchases and Sales?

We use a unique data set of more than 240,000 reported insider transactions across 15 European countries and the USA to analyze the link between country-level shareholder protection and abnormal returns following insider trades. We show that abnormal returns after insider transactions are positively correlated with country-level shareholder protection against expropriation by corporate insiders, which supports the information-content hypothesis. Market reaction to insider purchases increases with shareholder protection because shareholder protection enhances the transparency and trustworthiness of insiders’ actions, and limits possibilities for direct profit diversion, so that more information is eventually reflected in stock prices. For insider sales, shareholder protection decreases their negative information content. We conjecture that this is due to the effect of greater transparency and trustworthiness strengthening the diversification and liquidity reasons for selling in better shareholder protection countries. We find limited support for the rent-extraction hypothesis, which conjectures that shareholder protection is associated with insider trading dollar profits.
Factors Causing Enron's Collapse: An Investigation into Corporate Governance and Company Culture

Purpose: This paper investigates and evaluates the weaknesses of Enron’s corporate governance structures, weaknesses that lead to the collapse of the company. Overall, poor corporate governance and a dishonest culture that nurtured serious conflicts of interests and unethical behaviour in Enron are identified as significant findings in this paper. Methodology/Approach: Employing the case study method, the paper synthesises, analyses, and interprets all aspects of corporate governance that lead to Enron's collapse based on three main reports: The Powers Report (Powers, Troubh and Winokur 2002), the Testimony of Chief Investigation (Roach 2002), and The Subcommittee’s Report (United States Senate’s Permanent Subcommittee on Investigations 2002). Findings: Firstly, Enron’s Board of Directors failed to fulfil its fiduciary duties towards the corporation’s shareholders. Secondly, the top executives of Enron were greedy and acted in their own self-interest. Thirdly, many of Enron’s employees witnessed the wrongdoings of Enron’s top executives, and quite a few whistleblowers came forward. Lastly, Enron outsourced external auditing for its internal audit function instead of establishing a functionally internal audit mechanism and its external auditor acquiesced in the application of questionable accounting and fraudulent financial reporting. Originality/value: Although Enron's collapse has been widely discussed in the literature, no paper has been found that synthesises the various aspects of corporate governance that resulted in the Corporation's collapse. This paper contributes to the literature on the numerous weaknesses of Enron's corporate governance structures, including the following: the role of the Corporation' board, especially its top executives; the Corporation's corporate culture and whistle-blowing system; and the Corporation's internal auditor and external auditors.
Hedge Fund Portfolio Selection with Fund Characteristics

Abstract This paper examines hedge fund portfolio selection approaches in isolation and in the context of an investor’s overall portfolio. Characteristics-based portfolios that minimize risk delivers superior out-of-sample performance. For instance, a minimum variance portfolio tilting toward small funds with high alpha and strategy distinctiveness index and low systematic risk delivers an annualized Sharpe ratio of 2.03 with a maximum drawdown of 5.20%. Investors realize diversification benefits by shifting a portion of their wealth from 60 to 40 equity-bond portfolio to characteristics-based hedge fund portfolio. Investors recognize the attractiveness of characteristics-based portfolios, but do not target flows enough to erode their superior performance.
Auctions

This note describes four commonly used styles of auctions: English, Dutch, sealed-bid, and philatelist. Excerpt UVA-QA-0447 AUCTIONS This note defines four commonly employed styles of auctions: English, Dutch, silent, and philatelist. The English auction, also known as the ascending-price, open-outcry auction, is the form most English-speaking people think of when they think of an auction. An auctioneer seeks an initial bid from one of the assembled buyers with the expectation that those interested in the item will bid against each other until all but the highest bidder drops out of the bidding. The duty of the auctioneer is to obtain an initial bid and to acknowledge (and encourage) successive increases in an effort to realize the highest possible value. The Dutch auction, also referred to as the descending-price auction, begins with the auctioneer quoting a high price. The auctioneer then quotes successively lower prices at a predetermined increment and pace until a bidder claims the item at the currently quoted price. Unlike the English auction where the bids are offers to buy, the enunciated prices in the Dutch auction are invitations to buy. In addition to being implemented orally, the descending-price auction can be implemented electronically using a price clock or other device to signal the successively decreasing prices. When electronic means are used, buyers may be able to press a button to stop the clock and signal their acceptance of the currently quoted price. This auction takes its name from the famous tulip markets in Holland and is used extensively in Europe and the Middle East. The silent auction, otherwise known as the sealed-bid auction, is a process in which interested parties submit sealed bids for the item being auctioned. These bids are opened at a specified time and place. Generally, the highest bid wins the auction; however, this bidding process is also used when the seller wishes to consider a variety of issues beyond price when determining the most attractive bid. Examples include the selling of mineral rights and the awarding of government contracts. The philatelist auction, also known as the Vickrey auction for the Nobel laureate who studied the properties of these auctions, is a variant of the sealed-bid auction. The highest bidder, as usual, wins the auction but only pays the second-highest bidder's price. This bidding process is commonly used to auction rare stamps, hence its original name. This technical note was prepared by Sherwood C. Frey Jr., Ethel Corporation Professor. Copyright &#227; 1993 by the University of Virginia Darden School Foundation, Charlottesville, VA. All rights reserved. To order copies, send an e-mail to . No part of this publication may be reproduced, stored in a retrieval system, used in a spreadsheet, or transmitted in any form or by any means—electronic, mechanical, photocopying, recording, or otherwise—without the permission of the Darden School Foundation. Rev. 7/01.
Extraction and Characterization of Pectin from Grapefruit Peels

The present study was focused on the potential of red and white grapefruit peel as a source of pectin. Grapefruit peels were treated with 95% alcohol and the obtained alcohol-insoluble solids (AIS) were subjected to a sequential extraction with hot distilled water and hot 0.5% HCl. Comparative investigations were carried out with purified commercial citrus pectin. Chemical and physicochemical characterization of all pectin was accomplished. The yield of grapefruit peel pectin was 25% (dwb) It was found that pectin of the two types of grapefruit peels were similar in anhydrouronic acid content (AUА 60.95%). The grapefruit peel pectin for the red and white differed in their degree of esterification (DM 51.24-55.01%) and 50.848% for corresponding citrus pectin. Both grapefruit peel pectin were higher in their methoxyl content 8.875% for the red and 7.542% for the white, while corresponding citrus pectin was 6.798%. The acetyl content for the white grapefruit peel pectin was 1.634% and for the red was 0.55%, lower in comparison with the corresponding citrus pectin of 0.624. The grapefruit peel pectin contained L-arabinose, D-galactose, L-rhamnose and D-xylose. Gel-forming property of grapefruit peel pectin was of good quality similar to commercial pectin.
Convexity adjustments for affine term structure models

We present a general technique to obtain closed form convexity adjustments in an affine term structure set up, for products that are non-standard in terms of the timing or the rate of payment. We show how convexity adjustments are related to affine functionals, and as particular examples, we concentrate on the LIBOR in arrears and constant maturity swaps. Specifically, we contrast the convexity adjustments computed for Vasicek and CIR models, and show that the models produce convexity adjustments of different size and shape across the term structure. We also study in detail the impact of the mean reversion parameter and volatility on the shape and size of the convexity adjustment.
DIVERSIFICATION–PERFORMANCE RELATIONSHIP

This article investigates the relationship between product diversification and firm performance in the U.S. property–liability insurance industry using data over the 1994 through 2002 time period. Using various measures of product diversification and firm performance, we find that the extent of product diversification shares a complex and nonlinear relationship with firm performance. Our findings suggest that performance benefits associated with product diversification are contingent upon an insurer’s degree of geographic diversification. Robustness tests using subsamples and market returns for public firms show consistent results.
Corporate Governance and performance during turbulent financial markets

The objective of this study is to investigate the r elationship between stock market performance and ownership structure during plummeti ng and soaring financial markets in a Continental-European setting. Our results demonstra te the importance of ownership concentration, the presence of multiple blockholder s and the type of ownership to explain stock market performance. In addition, we find that t e results for extreme down markets are fundamentally different from the up market results. While ownership concentration is valued positively during down market periods, it is valued negatively during up market periods. Furthermore, the presence of multiple blockholders only influences the stock price during down market periods. Finally, firms controlled by a financial institution loose less value during down markets, while firms controlled by nonf unding families loose more value, compared to widely held firms, during down market p riods. No significant relationship is found during up market periods.
Possible mechanism of anti-inflammatory activity and safety profile of aqueous and ethanolic leaf extracts of Pistia stratiotes Linn (Araceae)

Pistia stratiotes is used extensively in inflammatory disorders in several countries including Ghana. The aim of the study was to investigate the anti-inflammatory property and possible mechanism of action of aqueous and ethanolic leaf extracts of Pistia stratiotes and to ascertain its safety for use. In separate experiments, acute inflammation was induced in the right hind paws of rats using carrageenan, histamine, serotonin, prostaglandin E, and bradykinin. Paw thickness (an indication of inflammation) were measured plethysmographically. Animals were grouped and treated with diclofenac, chlorpheniramine, and granisetron (reference anti-inflammatory agents), or aqueous and ethanolic extracts of Pistia stratiotes at doses of 30, 100, and 300 mg/kg orally. Control groups received distilled water. Paw thicknesses was measured at 30 or 60 min intervals for 2.5 to 4 h for the various procedures. The extracts at all doses signifi-cantly reduced (P. 0.05-0.001) paw thickness in all the models of inflammation except the 300 mg/kg doses in carrageenan and serotonin-induced inflammation. The anti-inflammatory effects of the extracts were comparable to the reference drugs. Acute and delayed toxicity test revealed that the aqueous extract causes hemolysis of red blood cells (reduced count and presence of uro-bilinogen in urine) and possible acute kidney function impairment (proteinuria and microalbu-minuria). The aqueous and ethanolic extracts of P. stratiotes have anti-inflammatory activity in acute inflammation induced with carrageenan, through the inhibition of histamine, serotonin, prostaglandin, and bradykinin. Hematological profile as well as liver and kidneys function should be monitored when used orally for the treatment of inflammatory disorders.
The novel cardiokine GDF3 predicts adverse fibrotic remodeling post-myocardial infarction

Background: Myocardial infarction (MI) induces a repair response that ultimately generates a stable fibrotic scar. Although the scar prevents cardiac rupture, an excessive profibrotic response impairs optimal recovery. Objective: To explore the regulation of fibroblasts proliferation through a paracrine action of cardiac stromal cells post-MI Methods: We carried out a bioinformatic secretome analysis of cardiac stromal PW1+ cells isolated from normal and post-MI mouse hearts to identify novel secreted proteins. Functional assays were used to screen secreted proteins that promote fibroblast proliferation. The expressions of secreted proteins candidates were subsequently analyzed in mouse and human hearts and plasmas. The relation between levels of circulating protein candidates and adverse post-MI cardiac remodeling was examined in a cohort of 80 patients with a first ST-elevation MI and serial cardiac magnetic resonance imaging (MRI) evaluations. Results: Cardiac stromal PW1+ cells undergo a change in paracrine behavior post-MI and secrete factors that promote fibroblast proliferation. Among these factors, growth differentiation factor 3 (GDF3), a member of the transforming growth factor-beta family, was markedly upregulated in the ischemic hearts and induced fibroblast proliferation at high level. In humans, GDF3 was detected in the plasma at day 4 post-MI and GDF3 circulating levels were significantly associated with an increased risk of adverse remodeling 6-month post-MI (adjusted Odds Ratio (OR) = 1.76 [1.03 - 3.00], p = 0.037). Conclusions Our findings define a mechanism for the pro-fibrotic action of cardiac stromal cells through secreted cardiokines, such as GDF3, a candidate marker of adverse fibrotic remodeling following MI.
Product Market Linkages and Managerial Risk Taking

A firm’s customers and suppliers make relationship-specific investments (RSI) whose value reduces if the firm undertakes risky investments. We hypothesize that the risk-taking incentives in the firm CEO’s compensation will lower the RSI by firms up and down in the vertical channel. We provide significant evidence that customer/supplier RSI declines with the risk-taking incentives of the firm’s CEO. Moreover, we find that RSI is more sensitive to the CEO’s risktaking incentives when they are more likely to increase the firm’s cash flow volatility. Our findings are robust to correcting for endogeneity and several measures for RSI and risk taking. JEL Classification G30