The Effect of Cost Categories and the Origin of their stickiness on Earnings Forecast: A Comparative Study

The main aim of this study is to separate the origins of “selling, general, and administrative costs (SG&A)” and “cost of goods sold (COGS)” stickiness, and investigate their sources effects on earnings forecast accuracy (EFA). In previous research, various micro and macro factors have been shown to affect asymmetric cost behavior. These factors are rooted in the industry and firm-specific characteristics or specific events, which may occur each year at national or international scales. In this study, in the first step, a new methodology is presented to separate the sources of cost stickiness, including a novel method for calculating cost stickiness for each firm-year. In the second step, we investigated the effect of each firm-year stickiness and each source of stickiness on the EFA. The statistical population of the study consisted of all companies listed on the Tehran Stock Exchange, from which 1080 observations in 2014-2018 period were selected and reviewed. Our results indicated that EFA has a negative and significant relationship with SG&A and COGS stickiness, stickiness of each year and each company, but no significant relationship was found with stickiness of each industry. Our results demonstrated that the stickiness of SG&A to COGS has a greater effect on the EFA. The findings suggest that the events of each year and the intra-organizational events of each company have a greater impact on cost behavior. Hence, it is necessary for managers and financial analysts to take into account each source of cost stickiness, especially year-specific events and firm-specific characteristics, and consider their effects in earnings forecast to improve their EFA

Analytical solution of a fractional differential equation in the theory of viscoelastic fluids

The aim of this paper is to present analytical solutions of fractional delay differential equations (FDDEs) of an incompressible generalized Oldroyd-B fluid with fractional derivatives of Caputo type. Using a modification of the method of separation of variables the main equation with non-homogeneous boundary conditions is transformed into an equation with homogeneous boundary conditions, and the resulting solutions are then expressed in terms of Green functions via Laplace transforms. This results presented in two condition, in first step when 0 ≤ α, β ≤ 1/2 and in the second step we considered 1/2 ≤ α, β ≤ 1, for each step 1,2 for the unsteady flows of a generalized Oldroyd-B fluid, including a flow with a moving plate, are considered via examples

Analytical solution of a fractional differential equation in the theory of viscoelastic fluids

The aim of this paper is to present analytical solutions of fractional delay differential equations (FDDEs) of an incompressible generalized Oldroyd-B fluid with fractional derivatives of Caputo type. Using a modification of the method of separation of variables the main equation with non-homogeneous boundary conditions is transformed into an equation with homogeneous boundary conditions, and the resulting solutions are then expressed in terms of Green functions via Laplace transforms. This results presented in two condition, in first step when 0 ≤ α,β ≤ 1/2 and in the second step we considered 1/2 ≤ α,β ≤ 1, for each step 1,2 for the unsteady flows of a generalized Oldroyd-B fluid, including a flow with a moving plate, are considered via examples

Evaluating the most common mutation in BRCAI and BRCA2 genes in women who had mothers with brest cancer and controls

Background and purpose: Breast Cancer is one of the health problems in every population. The aim of this study was to determine the frequency of BRCA1 and BRCA2 common mutations in women whose mothers were diagnosed with breast cancer. Materials and methods: A case�control study was performed in 109 females (less than 40 years of age) who had mothers with breast cancer. For scanning of genomic mutations in BRCA1 and BRCA2, genes mutation analysis was done in BRCA1 (exon2, 20) and BRCA2 (exon11) using Real Time PCR test. We also studied 109 healthy controls without family history of breast cancer. Results: No any mutation was found in this population. Conclusion: This study showed no mutation in affected and control group. Therefore, other mutations and genes may have a role in breast cancer pathogenesis in our population. © 2016, Mazandaran University of Medical Sciences. All rights reserved