A novel loop-mediated isothermal amplification approach for sex identification of Columbidae birds

Because it is difficult to differentiate male and female Columbidae birds (e.g., Columba livia) on the basis of morphology, detection of DNA fragments associated with Chromobox-Helicase-DNA binding genes or female-specific genes have been widely used. The objective was to establish a loop-mediated isothermal amplification system involving the 18S ribosomal RNA gene and a female-specific gene for sex identification of Columba livia birds. Unlike polymerase chain reaction (PCR), random amplification polymorphic DNA-PCR and amplified fragment length polymorphism-PCR, target DNA was amplified under isothermal conditions (the entire process was completed in 60 min). By modulating various parameters involved in amplification, e.g., concentrations of MgSO4, betaine, Bst polymerase, and deoxynucleotide triphosphates, as well as the relative ratio of outer/inner primers and temperatures, optimal conditions for both targets were established that had equal detection limits (62.5 ng). To simplify sex determination, direct observations of the presence of white precipitate (derived from magnesium pyrophosphates) were used for positive samples, which was compared with the whitish ring which formed in a negative sample after addition of CuSO4. This approach was a rapid alternative to electrophoresis or turbidimetry. DNA extracted from the blood and feathers of various birds were tested using loop-mediated isothermal amplification; results were consistent with a standard PCR. Thus, the assay was a simple, accurate, fast, and economical alternative suitable for veterinary practice

Earnings management and fraud

The purpose of the chapter is to provide a rounded discussion of the concept of earnings management and theories underpinning this behavior. The chapter presents an overview of the concept, with a discussion of alternative definitions and the theories related to this behavior, including the commonly discussed agency theory as well as some less-researched theories such as socioemotional wealth theory and upper echelons theory. The chapter also presents incentives that can lead to this behavior and evidence in the academic literature, followed by some examples in developed and developing countries of earnings management that spilled into fraud. The chapter concludes with a summary and some potential extensions to the academic literature