http://eksakta.ppj.unp.ac.id/index.php/eksakta/issue/feed Eksakta : Berkala Ilmiah Bidang MIPA 2020-04-30T16:06:13+00:00 Dr Rahadian Zainul M,Si (SCOPUS Author ID: 56737195700) rahadianzmsiphd@yahoo.com Open Journal Systems <p>Eksakta :&nbsp;<em>Berkala Ilmiah Bidang MIPA</em>&nbsp;&nbsp;is an open access journal and peer-reviewed that publishes either original article or reviews. The journal is dedicated towards dissemination of knowledge related to the advancement in scientific research. The prestigious interdisciplinary editorial board reflects the diversity of subjects covered in this journal. Under the realm of science and technology, the coverage includes environmental science, pure and applied mathematics, agricultural research and engineering, biology, biotechnology, bioinformatics, Healthcare sciences (including clinical medicine, preventive medicine &amp; public health), physics, biophysics, computer science, chemistry and bioengineering, to name a few. This Journal Is Published at 6 Month intervals On April and October</p> http://eksakta.ppj.unp.ac.id/index.php/eksakta/article/view/211 Convergence Analysis from the Solution of Riccati’s Fractional Differential Equation by Using Polynomial Least Squares Method 2020-04-30T16:06:13+00:00 Dian Nuryani dian16006@mail.unpad.ac.id Endang Rusyaman rusyaman@unpad.ac.id Betty Subartini betty.subartini@unpad.ac.id <p>Riccati's Fractional Differential Equation (RFDE) has become a topic of study for researchers because RFDE can model variety of phenomenon in science such as random processes, optimal control and diffusion problems. Phenomena that can be modeled in a mathematical form can make it easier for humans to analyze several things from that phenomenon. RFDE generally does not have an exact solution, therefore a numerical approach solution is needed, one of the methods that gives good accuracy to the actual or exact solution is Polynomial Least Squares, where the errors calculated based on mean absolute percentage error (MAPE) produce a percentage below 1%. In addition, the convergence of a sequence from approximate solutions indicates that the sequence will converge to a solution.</p> 2020-04-30T16:06:13+00:00 ##submission.copyrightStatement## http://eksakta.ppj.unp.ac.id/index.php/eksakta/article/view/210 The Effect of Ethanol Solvent Concentration on Antimicrobial Activities The Extract of Andalas Endophytic Bacteria (Morus Macroura Miq.) Fermentation Product 2020-04-30T15:43:22+00:00 Larasati Arum Utami larasatiarum01@gmail.com Dwi Hilda Putri dwihildaputri.08@gmail.com <p>Anti-Biotic resistance is a health problem globally.&nbsp;It is able to overcome with a new anti-microbial compound that can be produced from Andalas endophytic bacteria. This compound can be obtained through the fermentation process. In order to separate this active-compound, it is needed to use the extraction method. In this method, the solvent is functioned as the extractor. One of the solvent which is commonly used is ethanol. This research is aimed to know the effect of ethanol concentration toward antibacterial activity from extracted bacterial fermentation products of Andalas endophytic bacteria isolate JDT 1B. The fermented products are extracted by using the maceration method. The concentrations are 100%, 80%, 70%. A test of anti-microbial activity is used disk diffusion method.&nbsp; The extracted concentrations tested for each solvent are 50%, 25%, 12,5%, and 6.25%. Anti-bacterial activity is analyzed by using factorial design. The factorial result showed there is no significant contrast between ethanol concentration mentioned toward anti-bacterial activity from extracted bacterial fermentation products of Andalas endophytic bacteria Isolate JDT 1B. The concentration of extracted fermentation product using 70% ethanol has the same inhibition zone as control is 6,25%.</p> <p>&nbsp;</p> 2020-04-30T00:00:00+00:00 ##submission.copyrightStatement##