Judul: Metode pemberian gliserol dan lama ekuilibrasi pada proses pembekuan semen kerbau lumpur
Abstrak: Semen kerbau lumpur mudah rusak selama proses pembekuan. Masalah yang timbul selama proses pembekuan semen pada umumnya adalah pengaruh kejutan dingin terhadap sel yang dibekukan dan perubahan intraseluler selama proses pembekuan. Pemberian gliserol merupakan usaha untuk mengatasi masalah tersebut. Dalam penelitian ini dipelajari pengaruh metode pemberian gliserol dan lama ekuilibrasi pada berbagai parameter kualitas spermatozoa, meliputi persentase motilitas, persentase spermatozoa hidup, persentase tudung akrosom utuh dan persentase membran plasma utuh.
Keyword: Spermatozoa, Gliserol, Semen kerbau

Judul: Kriopreservasi Semen Kerbau Lumpur (Bubalus bubalis) dalam Pengencer Tris atau Skim Kuning Telur Menggunakan Krioprotektan Gliserol atau Dimetilformamida
Abstrak: Inseminasi buatan (IB) adalah salah satu teknologi reproduksi yang efektif dan dapat diterapkan secara luas di lapangan untuk meningkatkan populasi ternak kerbau. Kualitas semen beku merupakan salah satu faktor yang menentukan keberhasilan program IB. Kualitas semen beku kerbau di Indonesia saat ini masih terbilang rendah. Penelitian ini bertujuan mengevaluasi penggunaan gliserol dan dimetilformamida (DMF) sebagai krioprotektan dalam pengecer Tris dan Skim kuning telur untuk pembekuan semen kerbau lumpur. Semen ditampung dari dua ekor kerbau lumpur berumur 7 dan 10 tahun menggunakan vagina buatan. Semen segar dievaluasi secara makroskopis dan mikroskopis dengan rata-rata volume sebanyak 2.34 ml, berwarna krem, memiliki konsistensi encer hingga sedang, gerakan massa ++, motilitas spermatozoa 70.35%, viabilitas spermatozoa 83.21%, keutuhan membran plasma 83.78%, abnormalitas spermatozoa 15.34%, dan konsentrasi sebanyak 1 154 × 10⁶ spermatozoa mlˉ¹. Semen kerbau dibekukan dalam pengencer Tris dan Skim kuning telur dengan tambahan krioprotektan gliserol atau DMF masing-masing 4%, 5%, 6% dan 7%. Konsentrasi optimal penggunaan DMF adalah 5% baik dalam pengencer Tris maupun Skim kuning telur dengan motilitas setelah pembekuan masing-masing sebesar 46.41±1.21% dan 40.44±1.01%, viabilitas 67.65±1.32% dan 55.95±1.04%, keutuhan membran plasma 69.35±1.05% dan 57.41±1.09%, serta recovery rate 65.95±1.70% dan 57.50±1.24%. Penggunaan 7% gliserol dalam pengencer Tris maupun Skim kuning telur menunjukkan hasil terbaik dengan motilitas setelah pembekuan masing-masing sebesar 45.25±1.37% dan 42.33±1.36%, viabilitas 68.41±1.02% dan 61.52±1.42%, keutuhan membran plasma 69.58±1.16% dan 62.41±1.47%, serta recovery rate 64.27±1.91% dan 60.19±1.67%. Gliserol 7% dan DMF 5% memiliki kemampuan yang baik dalam melindungi spermatozoa selama pembekuan. Penggunaan DMF lebih dari 5% berdampak negatif terhadap spermatozoa. Selain dapat mencegah pembentukan kristal es, DMF juga dapat mengikat glutation. Kerusakan sel pada penggunaan DMF cukup banyak disebabkan oleh stres oksidatif kerena menurunnya kadar glutation seluler. Penggunaan gliserol dengan konsentrasi kurang dari 7% menunjukkan daya krioprotektif yang kurang optimal untuk pembekuan semen kerbau. Penggunaan pengencer Tris kuning telur menunjukkan hasil yang lebih baik dibandingkan pengencer Skim kuning telur. Hal ini diduga akibat kurangnnya kemampuan protein susu dan kuning telur (5%) dalam pengencer skim untuk menekan aktivitas protein PDC-109 dari plasma semen sehingga banyak fosfolipid dan kolesterol yang terlepas dari membran plasma. Berdasarkan hasil penelitian ini disimpulkan bahwa penggunaan gliserol 7% dan DMF 5% menunjukkan kualitas semen beku kerbau terbaik.
Keyword: dimetilformamida, gliserol, kerbau lumpur, krioprotektan, spermatozoa

Judul: Characteristic of Overshooting Top (OT) Based on  Himawari  8  Satellite  as  a  Convective  Cloud  Feature  that  Generates  Extreme Weather in the Java Island Region
Abstrak: Overshooting Top (OT) is a feature at the top of a convective cloud that is associated with extreme weather. Research on OT in tropical Indonesia is still very limited. The existence of geostationary satellites with wide area coverage and fast frequency observations is useful for observing the fast dynamics of the OT life cycle. Therefore, this study intends to analyze the relationship between OT and extreme weather, updraft and thermodynamic conditions of OT when extreme weather occurs, the best objective method for detecting OT in the day time and night time, and the spatiotemporal distribution of OT in the tropical region of Java Island during the 2018-2021 period. Based on visual analysis using visible channel and Himawari 8 sandwich products, 87% of extreme weather events in Java were accompanied by the appearance of OT. It indicates that the presence of the OT pattern is a convection cloud pattern or feature that is closely related to extreme weather events for the Java Island region. The existence of a time lag between the appearance of OT and extreme weather events on Java Island indicates that the OT of convection cloud can be used as a precursor or nowcasting for the appearance of extreme weather. Most of the convective cloud OT features during extreme weather events on Java Island have altitude that were only able to exceed the altitude of the equilibrium level and few were able to exceed the tropopause level of 9 km – 16 km. The difference in atmospheric conditions during extreme weather events on Java Island, which is in the tropics and subtropics, is a strong and unstable convective energy condition characterized by a larger CAPE, as well as unstable KI, LI, SI and TTI values. It is offset by kinematic factors in the form of a weak vertical wind shear (bulk wind shear 0-6 km) and a higher freezing point height. The difference between extreme weather events in the Java Island region and other tropical regions compared to subtropical regions is the strong updraft speed of convection clouds. The IRW Texture COMB algorithm based on the IRW-Texture Gradient modification and the COMB algorithm shows a significant increase in quality for detecting OT and non-OT pixels in Java. Rainy days with rainfall > 50 mm/day are very common in areas with an altitude of > 500 m. On the other hand, the level of convection activity which is indicated by the presence of OT and lightning is significantly reduced in this area. OT of convective clouds appear more frequently during the DJF season and less frequently during the JJA season. OT often appears during the day time and rarely at night time. Most OTs appear in the central part, away from the south and north coasts of Java Island during the day, while OTs that appear near the south and north coasts of Java Island can appear in the morning or afternoon.
Keyword: convective clouds, extreme weather, Overshooting Tops, Himawari 8 Satellite