Vol. 53 No. 1 (2021)

We propose families of estimators for the population mean using an exponential function in case of non-response. This situation is examined under two cases, Case I and II. The bias, MSE and minimum MSE are separately obtained for both cases. We compare the proposed estimators theoretically with the main estimators from the literature, such as Hansen and Hurwitz (1946), ratio, regression and exponential estimators. The conditions for which the proposed estimators are most efficient are obtained. Moreover, different empirical studies are conducted to support the theoretical results for both…

Isolation and identification of compounds and pharmacological activity of the Micromelum minutum grown in some countries has been done, but the Indonesian M. minutum has not been studied, either phytochemically or pharmacologically. This study aimed to determine the cytotoxic activity of Indonesian M. minutum leave extracts toward MCF-7 and 4T1 breast cancer cell lines. The leaves were obtained from M. minutum grow in Bantimurung National Park, Bulusaraung, South Sulawesi, and then were macerated gradually in hexane, ethyl acetate, and methanol. The cytotoxic activity of obtained extracts was…

A subset of vertices of a simple connected graph is a neighborhood set (n-set) of G if G is the union of subgraphs of G induced by the closed neighbors of elements in S. Further, a set S is a resolving set of G if for each pair of distinct vertices x,y of G, there is a vertex s∈ S such that d(s,x)≠d(s,y). An n-set that serves as a resolving set for G is called an nr-set of G. The nr-set with least cardinality is called an nr-metric basis of G and its cardinality is called the neighborhood metric dimension of graph G. In this paper, we characterize graphs of neighborhood metric dimension two.

The contribution of endophytic bacteria to the wellbeing of plants as biocontrol agents may be due to endophytic bacteria growing in the same niche as phytopathogens. This work was conducted to study the antagonistic activity of endophytic bacteria recovered from sweet sorghum against Sclerotium rolfsii, Fusarium solani, Fusarium oxysporum, Colletotrichum gloeosporioides in vitro and evaluate the mechanisms of these fungal inhibitions. We selected 78 endophytic bacteria from the stem and root of sweet sorghum plants. They were tested for antagonist activity by direct confrontation method.…

The SIQRS epidemic model developed in this study is intended to analyze the spread characteristics of the infectious disease tuberculosis. It is a modification of the SIQR model developed by Cao et al., using a stochastic model called the Continuous Time Markov Chains (CTMC) approach. Further analysis of the SIQRS model was done to determine the transitional probability, the outbreak probability, the expected time until disease extinction and to simulate the effect of quarantine treatment on the expected time until disease extinction. Based on the simulation it can be concluded that a…

In the present investigation we use the Jackson (p,q)-differential operator to introduce the extended Salagean operator denoted by Rkp,q. Certain bi-univalent function classes based on operator Rkp,q related to the Chebyshev polynomials are introduced. First, two coefficient bounds and Fekete-Szego inequalities for the function classes are established. A number of corollaries are developed by varying parameters involved.

In the present article, we give new techniques for proving general identities of the Popoviciu type for discrete cases of sums for two dimensions using higher-order ∇-divided difference. Also, integral cases are deduced by different methods for differentiable functions of higher-order for two variables. These identities are a generalization of various previously established results. An application for the mean value theorem is also presented.

The rhizome of Kaempferia galanga has been known to contain ethyl p-methoxycinnamate (EPMC) (1) as a main component, which has anti-inflammatory properties. Previously we have reported the structural modification of EPMC (1) to form another ester, nitrostyrene, and cinnammamide derivatives and then studied their structure-activity relationships as anti-inflammatory agent. In continuing our research, in this paper, we report the microwave-assisted Claisen-Schmidt condensation of EPMC (1) to synthesize a series of p-methoxystyryl ketones followed by a study of their anti-inflammatory activity.…

Micromelum minutum is used widely in traditional folk medicine. Although this species has been investigated extensively and several bioactive compounds have been isolated, little work has been done on Indonesian M. minutum. This research aimed to study the chemical constituents and biological activities of M. minutum cultivated in Bantimurung Bulusaraung National Park, South Sulawesi, Indonesia. The isolated compounds were assessed for their cytotoxicity towards MCF-7 and 4T1 cell lines by MTT method. The dried ground leaves of M. minutum were sequentially macerated with n-hexane, ethyl…