Judul: Effect of Salinity on Heart Rate of Eel (Anguilla bicolor)
Abstrak: Sidat merupakan salah satu biota perairan yang menjadi potensi pengembangan penangkapan, budidaya, dan konservasi. Sidat merupakan hewan katadromus yang melakukan migrasi ke laut untuk memijah, sehingga perlu diketahui perubahan kondisi fisiologisnya ketika akan bermigrasi dari hulu ke laut dalam akibat perubahan salinitas. Tujuan penelitian ini untuk mengetahui pengaruh salinitas terhadap detak jantung dan waktu pulih sidat. Detak jantung sidat ukuran 33-49 cm sebanyak 45 ekor diobservasi menggunakan teknik elektrokardiogram (EKG) dengan perlakuan empat salinitas yang berbeda yaitu 8, 16, 25, dan 33 ppt. Detak jantung direkam menggunakan karbon konduktor yang dihubungkan dengan bio-amplifier dan osiloskop. Hasil penelitian menunjukkan rata-rata detak jantung mengalami penurunan (brakikardia) terhadap perbedaan salinitas. Detak jantung sidat selama perlakuan adalah 68±2,01 dpm (salinitas 8 ppt), 66±3,62 dpm (salinitas 16 ppt), 64±4,29 dpm (salinitas 25 ppt), dan 59±4,52 dpm (salinitas 33 ppt). Detak jantung sidat (yellow eel) tidak berpengaruh signifikan terhadap perbedaan salinitas (p>0,05). Waktu pulih sidat berpengaruh signifikan terhadap perbedaan salinitas (p<0,05). Waktu pulih sidat semakin lama seiring dengan peningkatan salinitas., Eel is one of the aquatic biota that has the potential to develop capture, aquaculture, and conservation. Eels are catadromous animals that migrate to the sea to spawn, so it is necessary to know the changes in their physiological conditions when migrating from upstream to deep sea due to changes in salinity. The purpose of this research was to determine the effect of salinity on heart rate and recovery time of eels. Heart rate of eel with size 33-49 cm (n=45) was monitored using an electrocardiogram (ECG) technique with four different salinity treatment at 8, 16, 25, and 33 ppt. Heart rate was observed using a carbon conductor connected to a bio-amplifier and an oscilloscope. The average heart rate of eels was decreased (brachycardia) due to differences in salinity. The heart rate of eels during treatment was 68 ± 2.01 bpm (8 ppt salinity), 66 ± 3.62 bpm (16 ppt salinity), 64 ± 4.29 bpm (25 ppt salinity), and 59 ± 4.52 bpm (salinity 33 ppt). Heart rate of yellow eel didn’t significantly influence the difference in salinity (p>0,05). Eels heart rate recovery time was a significant effect due to difference in salinity (p<0,05). Recovery time of eel are getting longer on the salinity increases.
Keyword: detak jantung, salinitas, sidat

Judul: Analysis of eel (Anguilla bicolor) biorhythms and the effect of bait on controlled conditions
Abstrak: Sidat merupakan ikan katadromus yang bersifat nokturnal. Permintaan terhadap sidat meningkat dari tahun ke tahun yang mengakibatkan usaha budidaya dan penangkapan di alam juga semakin meningkat. Nelayan dalam melakukan penangkapan menggunakan kebiasaan dan pengalaman dalam penggunaan umpan dan waktu penangkapan. Penelitian ini bertujuan mengamati bioritme sidat dalam mencari makan dan respon sidat terhadap umpan yang berbeda. Umpan yang digunakan yaitu pasta, ikan lemuru, dan cacing tanah. Pengamatan bioritme dan respon terhadap umpan dilakukan dengan metode observasi secara langsung di laboratorium. Hasil pengamatan menunjukkan aktivitas sidat banyak terjadi pada sore hingga malam hari. Pada jam 16.30 WIB dan jam 01.00 WIB sidat banyak keluar dari shelter dan aktif berenang. Waktu yang dibutuhkan sidat untuk menghampiri umpan pasta pada jarak 50 cm rata-rata 19,8 detik. Waktu yang dibutuhkan sidat untuk menghampiri umpan cacing pada jarak 100 cm rata-rata 38,8 detik. Jenis umpan pasta dan cacing tanah direspon sidat dengan waktu yang lebih cepat., The eel is a catadromus fish that is nocturnal. Demand for eels are increasing from year to year, resulting in increased cultivation and catching in the wild. Fishermen in fishing use habits and experience in catching eel both for bait and fishing time. The study was aimed at observing the biorhythm of the eel in the search for feeding and the response of the eel to different feeds. The feeds used are pasta, Sardinella lemuru, and soil worms. Biorhythm observation and response to feed were carried out using direct observation methods in the laboratory. The observations results showed that eel activities mostly occur in the afternoon to evening. At 16.30 PM and 01.00 PM many eels come out of the shelter and actively swimming. The time it takes for an eel to approach the paste bait at a distance of 50 cm is an average of 19.8 seconds. The time it takes for an eel to approach the worm bait at a distance of 100 cm is an average of 38.8 seconds. Eels respond to types of pasta bait and earthworms more quickly.
Keyword: aktif, bioritme, umpan, sidat

Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology