1545 research outputs found
Sort by
An Adaptive Digital Predistortion Process Consisting of an Fir Filter and LMS Algorithm for use in RF Power Amplifier Linearization
Get PDFRadio Frequency (RF) Power Amplifiers (PA) are fundamentally non-linear due to their design and environmental effects, this non-linearity reduces performance and introduces distortion to the system. To improve the linear region of operation an adaptive Digital Predistortion Process (DPD) is used consisting of an adaptive Finite Impulse Response (FIR) filter utilizing the Least Means Square (LMS) algorithm. Unlike other DPD processes this one is adaptive in nature and requires no calibration allowing the digital pre-distorter to keep up with the dynamic changes in the PA non-linearity. The performance of this process is evaluated on the ability to increase the linearity of the PA thus decreasing distortion. The increase in linearity reduces the gain of harmonic frequencies and sidelobe intermodulation frequencies of the inputs. The performance is derived through multiple simulations in MATLAB which evaluate the effectiveness of the algorithm and the optimized design parameters. The results indicate that the adaptive algorithm is a viable method for reducing distortion and increasing the linear region of a PA. Due to these improvements this method would be a useful aid in RF system design and provides an economic advantage in high volume designs that require RF P As
An Evaluation of the Effect Of Degradation on IrisPlex SNPs
Get PDFThe information from short tandem repeats (STRs), the current standard forensic DNA typing technology, does not always result in identification. In these cases, there are other informative markers in DNA that can be used to help generate investigative leads, one of which is single nucleotide polymorphisms (SNPs). One of the uses of SNPs is for phenotype determination. Among the phenotypic characteristics that can be predicted is eye color. A commonly used tool for eye color prediction is the free, online statistical prediction model IrisPlex, which includes 6 SNPs known to control eye color.
While SNPs can be useful, they, like all DNA, are susceptible to degradation. Research on the effect of degradation on SNPs has already been done, but much of it uses massively parallel sequencing (MPS), which is not currently feasible for most crime labs. A stronger consensus is needed regarding the value of SNPs with instrumentation and techniques available to crime labs, such as real-time PCR.
Because SNPs are such small fragments, they will be highly resistant to the effects of degradation. Buccal swabs from 3 donors were degraded using two methods: UV exposure and burial in soil. Modern teeth and ancient remains found in the Gobi Desert were also analyzed to represent more natural degradation. DNA was extracted and quantified, and the degradation index was assessed. SNP profiles were generated using qPCR and input into IrisPlex to get an eye color prediction.
The SNPs were found to be resistant to degradation and the degradation index was not an indicator of SNP assay success or IrisPlex prediction accuracy. The intermediate eye colors did not produce as many accurate predictions as the brown eyes, which reinforces the need to focus on improving prediction accuracy for intermediate eye colors. The TaqMan assays are an option to generate the SNP data; however, there are other methods that likely work better, such as sequencing via capillary electrophoresis
Hedging Around a CEO Change: Further Evidence from the Oil and Gas Industry
Get PDFThis study examines hedging activities around hiring of chief executive officer (CEO). Data on the use of derivatives by a sample of oil and gas firms were hand collected from the 10-k filings and compared for several years before and after a CEO change. A regression method was employed to examine if hedging is associated with the CEO change after controlling for the effects of hedging variables. The findings show that net hedging decreased from three years prior to CEO hiring and increased for several years thereafter. The regression results show that hiring of a new CEO explains change in hedging one year after the CEO is hired when interactions among the explanatory variables are considered. This is one of the few studies that examine the relationship between hedging behavior and CEO change
Do Oil Shocks Affect Financial Stress? Evidence from Oil-Exporting and -Importing Countries
Get PDFIn recent years, there is increasing attention to examining the relationship between oil prices, financial markets, and the economy. Relatively little is known about the dynamic relationship between structural oil shocks and financial market stress of countries, which are majorly dependent on oil price fluctuations. This paper examines the impact of structural oil shocks (oil supply shocks, global aggregate demand shocks, speculative shocks, and other oil shocks) on the financial stress of major oil-exporting and-importing economies. In this study, we construct a financial stress index and using a structural vector autoregression model, we investigate the effects of oil price shocks on the financial stress of major oil-exporting and importing economies. We find evidence that global demand shocks, followed by speculative demand shocks, have significant impacts on financial stress. Furthermore, the US subprime crisis has a significant bearing on the response of the financial stress index to structural oil shocks. The magnitude of oil price shocks on financial stress has subdued during the post-crisis period
Evidence for the Presence of Borrelia burgdorferi in Invasive Breast Cancer Tissues
No full textBorrelia burgdorferi, the causative agent of Lyme disease has been found to disseminate and colonize various organs and tissues. B. burgdorferi shows exceptional survivability by modulating its surrounding tissue environment, regulating host genes, evading the immune system, and displaying resistant forms for escaping the immune response and antibiotic treatment. Recently B. burgdorferi DNA was detected in various types of breast cancer tissues associated with poor prognosis. In vitro evidence suggests that B. burgdorferi is capable of invading and increasing the migration and invasive properties of breast cancer cells. Yet, the presence of B. burgdorferi in invasive breast cancer tissues has not been explored. This study used commercially available, FDA approved breast cancer tissue microarrays with a total of 350 ductal, 32 lobular, 22 intraductal invasive breast carcinomas, along with 29 normal breast tissues for the evaluation of the presence of B. burgdorferi by fluorescent immunohistochemical (IHC) staining technique using B. burgdorferi s.s. specific antibodies. Immunohistochemistry staining paired with high resolution (3D) tissue imaging demonstrated the presence of not only spirochetal form but also B. burgdorferi aggregates deep inside the tissues. B. burgdorferi was detected in about 20% of the invasive lobular and ductal carcinoma followed by 14% for intraductal carcinoma but none of the normal breast tissues. Further, nested PCR and direct sequencing analysis confirmed the presence of B. burgdorferi DNA. We also analyzed CXCL chemokines which are known to be involved inflammatory and tumorigenic processes and found that B. burgdorferi-positive tissues expressed both CXCL8 and CXCL10 markers 25% of the times. We further analyzed any associated trends from the available individual patient data with B. burgdorferi infection available for those commercial tissues’ array. We found cancer grades I-II and II-III correlated with the highest B. burgdorferi positive tissues. For TNM staging system, results showed that T1N0M0 and T3N1M0 have the highest percentage of B. burgdorferi positive tissues. Additionally, samples from older age groups contained the most B. burgdorferi positive breast cancer tissues. Overall, this exploratory study provided evidence to the cancer associated infectious agents’ hypothesis. Based on this study we were able to confirm the presence of B. burgdorferi in invasive breast cancer tissues and show the involvement of major CXCL family members associated inflammatory processes
Distinguished Competency and Efficacy of Working Capital Management Ensuing Firm Survival, Liquidity, Solvency and Profitability: A Study on Automotive Industry
Get PDFLimited research interest in studying working capital management process, is found in the literature. However, working capital management has been the most crucial determinant factor for any industry’s survival, liquidity, solvency and profitability. Therefore, to tackle efficiently liquidity and profitability trade –off, all industries are compelled to improvise their working capital management strategies. Continuation of working capital management process at optimal level, expedites firm\u27s value creation and also facilitates to design framework in smoothening financial constraints so as to make effective usages of firm’s resources. The paper argues that automotive industry occupies a significant proportion of global economy. Therefore, an effort has been made to undertake an in-depth study on the industry. The study besides identifying the industry leader, explores diverse techniques to advance comparative study on the industry efficiency level in managing working capital process. The research outcome facilitates investors to choose the most commendable automotive companies for investments
Contribution of Exchange Traded Funds in Hedging Crude Oil Price Risk
Get PDFIn this study, we empirically analyze the contributions of three crude oil-based exchange traded funds (ETFs) and the futures contract in hedging crude oil price risk. In order to measure hedging contributions of ETFs, we estimate the usual minimum variance hedge ratios as well as the quantile based minimum variance hedge ratios based on three different methods. We also compute the hedging effectiveness of the futures contract and three ETFs. We find that ETFs can be used as hedging instruments especially for the longer hedging horizons and extreme quantiles. However, overall, we find the futures contract to be the most effective instrument for hedging
Information Sharing in a Green Supply Chain with a Common Retailer
Get PDFIn the paper, we analyze the problem of information sharing in a green supply chain with two competing manufacturers selling environmentally friendly substitutable products in markets through a common retailer. We develop a game-theoretic framework of a network supply chain structure. The study shows that (a) the manufacturer is better off while the retailer is worse off when the retailer shares his private information with the manufacturer; (b) the equilibrium greening levels are the highest when both the manufacturers are informed; (c) under intense competition, the retailer has an incentive to share the information with the manufacturer; (d) the equilibrium greening levels decrease with information inaccuracy. This study shows the existence of a contracting mechanism the manufacturers can employ to induce information sharing. This study’s results will be helpful to managers of green supply chain structures to make marketing and operational decisions under uncertain situations. The main contribution of this study is that it explores the problem of information sharing in a green supply chain under competition
Can Ethical Leaders Enhance Knowledge Sharing? The Role of Psychological Capital and Anticipated Reciprocal Relationships
Get PDFThe aim of the paper is to empirically investigate the influence of ethical leadership and psychological capital on knowledge sharing in business organizations. Furthermore, the paper investigates the mediating role of psychological capital and moderating role of anticipated reciprocal relationships in the relationship of ethical leadership with knowledge sharing. The analysis has been conducted on data gathered from 248 members of information technology (IT) companies by making use of survey questionnaire. Hypotheses are tested by analysing the data using structural equation modelling (SEM) and PROCESS macro. The study found that ethical leadership and psychological capital have positive effect on knowledge sharing. Ethical leadership also impacts psychological capital positively. Further, psychological capital acts as a mediator and anticipated reciprocal relationships act as moderator in the relationship of ethical leadership and knowledge sharing. This study establishes new antecedents of knowledge sharing, emphasizes the importance of ethical aspects of leadership in managing knowledge resources and enrich literature of Knowledge Management (KM), leadership, positive organizational behavior and human resources management. It further gives new perspectives to practitioners by recognizing the significance of ethical leadership, psychological capital and anticipated reciprocal relationships to enhance knowledge sharing. To the best of authors’ knowledge, this study is one of few initial studies to examine the linkages between ethical leadership, knowledge sharing and psychological capital as well as the role of anticipated reciprocal relationships therein
Service Brand Loyalty Antecedents: A Multimodal Analysis of Brand Name Attributes, and Attitudes Toward Services and Advertisements
Get PDFThe study investigates service brand loyalty antecedents as evidenced by brand name attributes and attitudes toward services and advertisements. Print advertisements from ten service industries are analyzed using multiple regression. A model is provided examining the influences of service type, brand name attributes, and attitudes toward the services and advertisements on respondent propensity for service brand loyalty. Significant loyalty resulted with all advertisements for attitudes toward the service provided and the advertisement with exception for airlines. Brand name attributes impacted only four services including design, healthcare, insurance, and airline offerings. Across all industries, service attitude had the greatest effect followed by advertisement attitude. Loyalty for design and insurance services was influenced by all three antecedents with the greatest impact demonstrated for health care. In contrast, airlines exhibited the least effects. Services rated as good or likeable, with brand names that sent a message and explained the service, and whose advertisements evoked useful and informative attitudes were the strongest loyalty indicators. Further insight is gained as tailored advertising strategies across industries with recognition for specific service types are recommended. A one-size standardized approach is not effective as service type is proven to have significant impact on brand loyalty. The model findings provide comprehensive support for prior recognition of service type and identified service advertisement antecedents which will then foster increased service brand loyalty