Judul: Toxicity Nitrite on Physiological Responses of Day of Culture 30 Vannamei Shrimps Litopenaeus vannamei
Abstrak: Nitrit-N merupakan bentuk nitrogen yang relatif bersifat tidak stabil dan dapat teroksidasi serta terbentuk dari proses nitrifikasi. Nitrifikasi merupakan proses oksidasi amonia (NH3-N) menjadi nitrit-N (NO2-N) dan nitrat-N (NO3-N). Konsentrasi nitrit-N yang tinggi dalam suatu perairan bersifat toksik bagi udang vaname dan menyebabkan stres hingga kematian. Penelitian ini bertujuan untuk mengukur toksisitas nitrit-N dalam lingkungan perairan terhadap produktivitas dan respons fisiologis udang vaname Litopenaeus vannamei DOC 30. Penelitian ini terbagi menjadi tiga tahap, yaitu uji pendahuluan, uji letal, dan uji subletal dengan menggunakan metode rancangan acak lengkap (RAL). Pengamatan mortalitas hewan uji dilakukan pada jam ke-24, 48, 72, dan 96. LC50 pemaparan nitrit-N selama 96 jam pada udang vaname ukuran DOC 30 adalah 88,88±28,35 mg L-1NO2-N. Konsentrasi nitrit-N pada penelitian ini menunjukkan penurunan seiring dengan lama waktu pemaparan nitrit-N. Pemaparan nitrit-N dengan konsentrasi 45 mg L-1 pada udang vaname DOC 30 dapat menekan survival rate mencapai 55,33±4,04%, penurunan pertumbuhan panjang mutlak sebesar 79,80 %, dan penurunan pertumbuhan bobot mutlak sebesar 85,70%, serta peningkatan respons fisiologis (Total hemocyte count, glukosa darah, dan kolesterol), Nitrite-N is a form of nitrogen that is relatively unstable and easily oxidized which is made up of the nitrification process. Nitrification is the process of ammonia (NH3-N) oxidation that turns into nitrite-N (NO2˗N) and nitrate-N (NO3- N). The high concentration of nitrite-N in particular water is toxic for the vannamei shrimps, and it causes stress to death. This research aims to measure the nitrite-N concentration in the water environments toward product as well as the physiological response of DOC 30 vannamei shrimp Litopenaeus vannamei. This research is divided into three steps, which are preliminary, lethal, and sub-lethal tests by using a completely randomized design method. The observation of the mortality of tested animals was conducted at the 24th, 48th, 72nd, and 96th hours. LC50 of the nitrite-N exposure for 96 hours at DOC 30 vannamei shrimps is 88,88±28,35 mg L-1 NO2-N. Nitrite-N concentration in this research showed the decline along with the duration of nitrite-N exposure. Nitrite-N exposure with the concentration of 45 mg L-1 in the DOC 30 vannamei shrimp can press of survival rate values until 55,33±4,04%, decline absolute length growth by 79,80 %, decline absolute weight growth by 85,70%, and increased physiological response (Total hemocyte count, glucose, cholesterol). Keywords: LC50, Litopenaeus vannamei, nitrite-N
Keyword: LC50, Litopenaeus vannamei, nitrite-N, stress, toxic

Judul: Exposure to Nitrite Toxicity 1 mg L-1 to Productivity and Physiological Responses of Post Larvae 15 Vannamei Litopenaeus vannamei Shrimp at Different Salinities
Abstrak: Paparan Toksisitas Nitrit 1 mg L-1 Terhadap Produktivitas dan Respon Fisiologis Post Larvae 15 Udang Vannamei Litopenaeus vannamei di Salinitas Berbeda. Dibimbing oleh YUNI PUJI HASTUTI dan KUKUH NIRMALA. Nitrit-N merupakan bentuk nitrogen yang relatif bersifat tidak stabil dapat teroksidasi dan terbentuk dari proses nitrifikasi. Nitrifikasi merupakan proses oksidasi amonia (NH3-N) menjadi nitrit-N (NO2-N) dan nitrat-N (NO3-N). Konsentrasi nitrit-N yang tinggi dalam suatu perairan di salinitas rendah bersifat toksik bagi udang vaname dan menyebabkan stres hingga kematian. Penelitian ini bertujuan untuk mengetahui paparan toksisitas nitrit terhadap produktivitas dan respon fisiologis post larvae 15 udang vannamei Litopenaeus vannamei di salinitas berbeda. Penelitian pemeliharaan dengan menggunakan metode rancangan acak lengkap (RAL). Pengamatan pemeliharaan hewan uji dilakukan pada selama 14 hari pada udang vaname ukuran post larvae 15 dengan perlakuan 1 mg L-1 NO2-N dan kontrol pada masing-masing salinitas 10 g L-1, 15 g L-1, dan 20 g L-1. Konsentrasi 1 mg L-1 NO2-N di salinitas berbeda terutama di salinitas rendah pada penelitian ini menunjukkan hasil penurunan dari berbagai parameter uji. Pemaparan 1 mg L-1 NO2-N dengan salinitas 10 g L-1 pada udang vaname post larvae 15 dapat menurunkan survival rate mencapai 56,67±5,77%, penurunan pertumbuhan panjang mutlak mencapai 1,41±0,20 cm, dan penurunan pertumbuhan bobot mutlak sebesar mencapai 0,20±0,01 g, serta penurunan dan peningkatan respons fisiologis (aktivitas lisozim dan glukosa) Kata kunci: aktivitas lisozim, glukosa, Litopenaeus vannamei, nitrit-N, toksik, salinitas, Exposure to Nitrite Toxicity 1 mg L-1 to Productivity and Physiological Responses of Post Larvae 15 Vannamei Litopenaeus vannamei Shrimp at Different Salinities. Supervised by YUNI PUJI HASTUTI and KUKUH NIRMALA. Nitrite-N is a relatively unstable form of nitrogen and can be oxidized and is formed from the nitrification process. Nitrification is the process of oxidizing ammonia (NH3-N) to nitrite-N (NO2-N) and nitrate-N (NO3-N). High concentrations of nitrite-N in waters at low salinity are toxic to white vannamei shrimp and cause stress to death. This study aims to determine the exposure to nitrite toxicity on productivity and post-larvae physiological response of 15 vannamei shrimp Litopenaeus vannamei in salinity. Maintenance research using completely randomized design (CRD). Rearing of the test animals was carried out for 14 days on vannamei shrimp post larvae size 15 with 1 mg L-1 NO2-N treatment and control at 10 g L-1, 15 g L-1, and 20 g L-1 salinity, respectively. The concentration of 1 mg L-1 NO2-N in different salinity, especially at low salinity, in this study showed a decrease in various test parameters. Exposure to 1 mg L-1 NO2-N with a salinity of 10 g L-1 in post larvae white vannamei shrimp 15 can lower the survival rate to 56.67±5.77%, the decrease in absolute length growth reaches 1.41±0.20 cm, and an absolute decrease in growth of 0.20±0.01 g, as well as a decrease and an increase in physiological responses (Lysozyme and glucose activity) Key words: Lysozyme activity, glucose, Litopenaeus vannamei, nitrite-N, toxic, salinity
Keyword: Lysozyme activity, glucose, Litopenaeus vannamei, nitrite-N, toxic, salinity

Judul: : Persamaan Tunggal sebagai Representasi Kurva Komposit
Abstrak: A mathematical method is introduced to represent a composite curve based on an extension of analytic geometry. The representation is given either with a single equation or with two equations, in the case of parametric representation. This method permits the representation of composite curves in similar manner to the conventional representation of non-composite curves. Some mathematical tools, including Heaviside unit step function and periodizer function, are used in the establishment of a single equation. In this paper, regular equations of regular and irregular polygon, as well as composite curves of two dimensions, are implemented using a computer algebraic system, Mathematica.
Keyword: