In this paper, the effects of hydrothermal pretreatment on biogas enhancement production rates from water hyacinth mixed with buffalo dung was investigated.The focus of the experiment was on thetime of hydrothermal pretreatment and the ratio of water hyacinth with buffalo dung. The hydrothermal pretreatedsubstrates were characterized by TDS, BOD and pH.The hydrothermal pretreatment of 60 minutes with the ratio of water hyacinth to buffalo dung 1:2 showed the highest biogas production rateat 7889 ml/day. However, the highest methane composition was 52.82% which resulted on the hydrothermal treatment of 30 minutes with equal ratio of water hyacinth and buffalo dung. Thus, the optimum of methane yield obtained at hydrothermal pretreatment for 30 minutes with equal ratio of water hyacinth to buffalo dung is 2856 ml/day.The hydrothermal pretreatment increases the rate production of biogas 102% and the methane yield51% relative to untreated water hyacinth.The ratio of water hyacinth and buffalo dung has a great impact on biogas productionrateand compositions for hydrothermal pretreated substrates.

This study aims to determine the increase students' communication skills using bilingual preview review with setting jigsaw learning in the class VII SMPN 1 Tangerang on the concept of environmental management. The method used in this research was quasiexperimental research with one group pretest posttest design. In this research, the sample was class VII I, there are 30 student participant by purposive sampling. The instruments used the observation paper and written communication ability test. The result of the research is t-test result get t count = 11.41 and t table at α = 0.05 is 1,69. t count = 11,41 > t table =1.69 which indicates that there is an increase students' communication skills using bilingual preview review with setting jigsaw learning in the class VII SMPN 1 Tangerang on the concept of environmental management.

Sleep is a basic human need. Poor sleep quality can have an impact on students' health and academic performance. Nursing students at the end of the level transfer program have the risk of poor sleep quality due to the high academic task load coupled with other assignments besides lectures that can take up student break time. One of the factors that affect the quality of sleep is stress, and among students it is called academic stress. The purpose of this study was to determine the relationship between academic stress and sleep quality in the final year students of a level transfer program. The study was conducted at one of the campuses in the city of Padang using a correlation analytic research design with a cross sectional approach. The sample in this study amounted to 64 students at the end of the level transfer program with the total sampling technique. This research was conducted from October to November 2019. Data was collected using the Pittsburh Sleep Quality Index and Student Academic Stress Scale research instruments. The results of this study indicate that nursing students at the end of the level transfer program experience poor sleep quality with high academic stress. Correlation analysis provides a linear and positive pattern of relationship between academic stress and sleep quality of nursing students at the end of a level tansfer program, with a very strong correlation strength level, which means that the higher the student's academic stress, the worse the quality of sleep.. It is expected that students can manage academic stress with stress management and time management, so as not to have an impact on the quality of student sleep.

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Abstract. Murni D, Lestari U, Indriwati SE, Efendi A, Maryani N, Amin M. 2020. Morphometric diversity and phenotypic relationship among indigenous buffaloes of Banten, Indonesia. Biodiversitas 21: 933-940. This study aimed to describe the morphometric diversity and phenotypic relationship among indigenous buffaloes of Banten, Indonesia. In this study, 125 buffaloes from six regions were investigated based on 11 morphometric characters. Morphometric diversity was analyzed using multivariate discriminant analysis. The Euclidean genetic distances were used to estimate the phenotypic relationship among the buffalo populations. The indigenous buffaloes of Banten have high morphometric diversity, with a coefficient from 2.83 to 41.43%. The body length and chest circumference can be used as a morphometric marker to determine potential indigenous buffaloes as their high correlation coefficient value (0.506). The Serang district buffaloes have the highest mean of body length and chest circumference, which shows that this population is potential compared to the populations from other regions. The morphometric of buffalo population from Serang City, Cilegon City, Serang District, and Pandeglang District tend to be homogenous. Meanwhile, Lebak and Tangerang District population tends to heterogeneous. According to Euclidean distance analysis, the proximate phenotypic relationship was between Serang and Pandeglang District's buffalo populations. Our results indicated that morphometric diversity and phenotypic relationships of the populations were related to geographical origins and can be used to determine the potential indigenous of buffaloes.

The infinite series is an infinite sum of elements of a sequence of real numbers. A main thing related to the infinite series is to determine its convergence (convergent or divergent). Purpose this research were to analyze and determine a comparison and characteristics of each convergence test, such as: D'Alembert test, Raabe test, Gauss's test, Cauchy's Root Test, and Logarithm Test. A method used descriptive method by analyzing theories relevant to the problems discussed and based on literature study.The results showed that each convergence test had characteristics for its convergence test. The D'Alembert Ratio test is easier to use in a series that contains the formn! ,rn, and nn. Raabe test used if the ratio test obtained value limit comparison is, so the test does not give conclusion. Whereas logarithmic test is used in the infinite series that contains the logarithmic form. The Cauchy n-th root test, can be used to determine the absolute series convergence of the nth power

Smartphone adalah telepon pintar yang mempunyai fitur-fitur canggih dengan kemampuan tinggi serupa komputer. Smartphone dimiliki oleh semua mahasiswa di departemen matematika FMIPA Universitas Negeri Padang. Penggunaan smartphone yang baik akan membantu mahasiswa dalam perkuliahan dan sebaliknya penggunaan yang tidak baik akan membawa dampak negatif kepada mahasiswa. Tujuan penulisan artikel ini untuk mengetahui bagaimana persepsi mahasiswa Departemen Matematika FMIPA Universitas Negeri Padang terhadap pemanfaatan Smartphone dalam perkuliahan. Penelitian ini adalah penelitian kuantitaif dengan analisis data deskriptif dengan metode survei. Angket persepsi mahasiswa digunakan sebagai instrumen pengumpulan data persepsi mahasiswa departemen matematika yang mengambil mata kuliah Statistika Matematika pada semester Januari-Juni 2022. Hasil penelitian adalah 52% mahasiswa mempunyai persepsi yang baik ,31% sangat baik dan 16,3% tidak baik terhadap pemanfaatan (dampak positif) smartphone dalam menunjang perkuliahan sedangkan untuk persepsi mahasiswa terhadap dampak negatif smartphone terhadap perkuliahan adalah 41,64% setuju dan 9,42% sangat setuju dan yang tidak setuju dan sangat tidak setuju sebanyak 48,94%. Dengan baiknya persepsi penggunaan smartphone dikelas diharapkan mampu memberikan alternatif alat pembelajaran yang menunjang proses peningkatan prestasi belajar mahasiswa.

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