CONSTRUCTIVE AND INVESTIGATE THE GENERALIZED CONVOLUTION WITH THE WEIGHT FUNCTION FOR THE FOURIER COSINE AND SINE TRANSFORMS

Joint Research on Environmental Science and Technology for the Eart

Evaluation of plant growth regulators on root formation of semihardwood and hardwood cuttings of Sarcandra glabra (Thunb.) Nakai

The aim of this study is to evaluate the effects of three types of plant growth regulators (α- naphthyl acetic acid, indole-3-acetic acid and β-indol butyric acid) on the root formation of the semihardwood and hardwood cuttings of Sarcandra glabra (Thunb.) Nakai. The effects of plant growth regulators on root formation were evaluated based on living percentage, rooting percentage, secondary rooting percentage, and the number and the length of roots. The results showed that the best root growth regulator was β-IBA. The overall effective concentrations of growth regulators were 1.0 and 1.5%. The living percentage of the semihardwood cuttings was lower than that of the hardwood cuttings. However, the root growth parameters of the semihardwood cuttings were better than those of the hardwood cuttings.

Firm Characteristics and Capital Structure Decision: Evidence from Seafood Processing Enterprises in the South Central Region of Vietnam

Purpose: The aim of this study is to investigate the firm characteristics that affect capital structure of seafood processing companies in South Central Coast of Vietnam. In addition, this study also explores the differences in capital structure among companies with different types of ownership in various regions as well as those with debt ratio greater than and less than the optimal debt threshold (57.39 per cent, see Nguyen Thanh Cuong (2014) for details). Design/methodology/approach: The investigation has been performed using panel data procedure for a sample of 90 unlisted seafood processing enterprises in the South Central region (SEASCRs) and 22 listed seafood processing enterprises in the other region of Vietnam (SEALISTs) during 2005–2011. The firm characteristics are analyzed as determinants of capital structure according to different explanatory theories. The hypothesis that is tested in this paper is that the debt ratio at time t depends on the size of the firm at time t, tangible fixed assets of the firm at time t, the growth opportunities of the firm at time t, the profitability of the firm at time t, the business risk of the firm at time t, its liquidity ratio at time t, its interest expense ratio at time t and its income tax ratio at time t. The SEASCRs that maintain a debt ratio above 57.39 per cent using a dummy variable are also distinguished. We also using a dummy variable to evaluate the differences about the capital structure of SEASCRs with regard to firm ownership. In addition, with regard to evaluate the differences about the capital structure of seafood processing enterprises in different regions, we also using a dummy variable.Findings: The findings of this study justify the hypothesis that there is a negative relation between the debt ratio of the firms and their tangible fixed assets, their growth opportunities, their profitability, their liquidity ratio and their business risks. Size and interest expense ratio appears to maintain a positive relation. According to the dummy variable there is a differentiation in the capital structure among the SEASCRs with a debt ratio greater than 57.39 per cent and those with a debt ratio lower than 57.39 per cent. In addition, this study also findings the differences in capital structure among SEASCRs with different types of ownership and the differences about the capital structure of seafood processing enterprises in various regions. Our findings are consistent with the Trade off theory and Pecking order theory. Originality/value: The findings suggest implications for SEASCRs on flexible usage of financial leverage to increasing firm value and lowering cost of capital. Keywords: Capital Structure, Debt Ratio Threshold, SEASCRs, regional characteristics. JEL code: G32, G3

Trigonometric weighted generalized convolution operator associated with Fourier cosine-sine and Kontorovich-Lebedev transformations

The main objective of this work is to introduce the generalized convolution with trigonometric weighted $\gamma=\sin y$ involving the Fourier cosine-sine and Kontorovich-Lebedev transforms, and to study its fundamental results. We establish boundedness properties in a two-parametric family of Lebesgue spaces for this convolution operator. Norm estimation in the weighted $L_p$ space is obtained and applications of the corresponding class of convolution integro-differential equations are discussed. The conditions for the solvability of these equations in $L_1$ space are also founded.Comment: 12 page

Recommending Surface Water Quality Monitoring for the Nature Reserve Using Multivariate Statistical Methods

Lung Ngoc Hoang Nature Reserve has a crucial role in conserving and protecting the natural ecosystem and biodiversity in the Mekong Delta, Vietnam, and the local communities also receive great benefits from aquatic resources in this nature reserve. This study was conducted to assess water quality in the Lung Ngoc Hoang Nature Reserve and to provide important information for the monitoring program using multivariate statistical methods. Water samples were collected bimonthly from fifteen locations belonging to five functional zones of the nature reserve (i.e., buffer zone, main canal, administrative and service zone, ecological restoration zone, and strictly protected zone). The physiochemical properties of water samples were measured, including temperature, pH, electrical conductivity (EC), total suspended solids (TSS), dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), sulfate (SO42-), iron (Fe2+), and aluminum (Al3+). The results showed that the levels of TSS, COD, and Fe2+ exceeded the Vietnamese standard on surface water quality, and the DO level was also far below the standard. Besides, the concentrations of TN, TP, and Al3+ in the nature reserve area showed the risk of eutrophication and negative effects on aquatic organisms. Problems of water quality were observed in the main canal and the administrative and service zones more than in the other zones. Cluster analysis (CA) suggested a reduction in the number of monitoring frequencies and locations to four months (i.e., January, April, July, and September) and twelve locations, respectively. This reduction allows for a decrease in the effort and cost of the monitoring program with adequate information to evaluate water quality. Moreover, principal component analysis (PCA) identified five principal components, which could explain 80.98% of the total variance of the initial dataset. Potential pollution sources were also recognized based on PCA, including the nature properties of sulfate-acid soils, livestock, fertilizer, and domestic activities. The findings of this study can enhance our understanding of water quality in the nature reserve area and the effectiveness of future monitoring programs. Doi: 10.28991/CEJ-SP2023-09-015 Full Text: PD

Generalized Convolution Transforms and Toeplitz Plus Hankel Integral Equations

Mathematics Subject Classification: 44A05, 44A35With the help of a generalized convolution and prove Watson’s and Plancherel’s theorems. Using generalized convolutions a class of Toeplitz plus Hankel integral equations, and also a system of integro-differential equations are solved in closed form