Judul: Quality of Chilled Ram in Tris Egg Yolk-Glucose  Diluent with Melatonin as an Antioxidant
Abstrak: Radikal bebas dan stres oksidatif selama pengolahan semen menyebabkan kerusakan membran plasma spermatozoa yang mengakibatkan penurunan motilitas dan viabilitas. Melatonin merupakan antioksidan yang efektif untuk menetralkan radikal bebas dan mengurangi kerusakan oksidatif sehingga mampu melindungi spermatozoa. Penelitian ini bertujuan mengevaluasi pengaruh penambahan melatonin dan menentukan dosis efektif melatonin dalam pengencer tris kuning telur-glukosa terhadap kualitas semen cair domba yang disimpan pada suhu 4 °C. Koleksi semen dilakukan dengan metode vagina buatan, kemudian semen dievaluasi secara makroskopis dan mikroskopis. Semen dengan motilitas sebesar ≥70% diencerkan pada kelompok tris kuning telur-glukosa (TKTG), tris kuning telur-glukosa dengan melatonin 0,5 Mm (TKTG + M0,5), tris kuning telur-glukosa dengan melatonin 1 mM (TKTG + M1), tris kuning telur-glukosa dengan melatonin. 2 mM (TKTG + M2). Semen cair disimpan selama 5 hari (H0–H5) pada suhu 4 °C, kemudian dievaluasi kualitas semennya setiap 24 jam. Parameter evaluasi semen berupa motilitas, viabilitas, abnormalitas, dan membran plasma utuh spermatozoa. Hasil penelitian menunjukkan kualitas semen cair tidak berbeda signifikan pada H0 (P>0,05). Penambahan melatonin secara umum, memiliki nilai lebih tinggi daripada kontrol dan mampu melindungi serta mempertahankan kualitas semen cair. Pengencer TKTG + M1 berdasarkan hasil penelitian, adalah perlakuan terbaik yang ditunjukkan dengan nilai dari parameter lebih tinggi daripada perlakuan lainnya., Free radicals and oxidative stress during semen processing damage the plasma membrane of spermatozoa resulting in reduced motility and viability. Melatonin is an antioxidant that can neutralize free radicals and reduce oxidative damage so it can protect spermatozoa. The aim of this study was to evaluate the effect of adding melatonin and determine the effective dose to tris egg yolk-glucose diluents on the quality of chilled ram semen stored at 4 °C. Semen was collected using an artificial vagina, and then examined macroscopically and microscopically. Semen with motility of ≥70% was grouped into different extenders: tris egg yolk glucose (TEYG), tris egg yolk glucose extender with 0.5 mM melatonin (TEYG + M0.5), tris egg yolk glucose extender with 1 mM melatonin (TEYG + M1), tris egg yolk glucose extender with 2 mM melatonin (TEYG + M2). All semen samples were stored at 4 °C for 5 days (H0–H5) and examined every 24 hours. Semen were examined for spermatozoa motility, viability, abnormality, and membrane plasma integrity. The results showed that there were no significant changes of semen quality on H0 (P>0.05). In general, the melatonin supplemented groups had a higher value than the control. Melatonin supplementation is able to protect and maintain the quality of chilled semen. In addition, the result showed that TEYG + M1 extender was the best extender treatment, which was indicated by higher values than other treatments.
Keyword: antioxidant, free radicals, melatonin, ram, tris egg yolk-glucose

Judul: Pemeliharaan Kualitas Semen Cair Domba dalam Pengencer AndroMed dengan Penambahan Melatonin Sebagai Antioksidan
Abstrak: Oxidative stress during semen processing may cause damage to ram spermatozoa cells, resulting in decreased motility and plasma membrane integrity. Melatonin is an effective antioxidant in neutralizing reactive oxygen species and stimulating the activity of antioxidant enzymes to protect spermatozoa cells. The aim of this research is to evaluate the effect of melatonin supplementation at multiple concentrations on the quality preservation of chilled ram semen in an AndroMed diluent when stored at 4°C. Semen is collected from a sexually mature ram using an artificial vagina, followed by a microscopic evaluation. Viable semen samples with motility of >70% are divided into 4 experimental groups: AndroMed (A) as a control, AndroMed with 0.5 mM melatonin (A + M0.5), AndroMed with 1 mM melatonin (A + M1), and AndroMed with 2 mM melatonin (A + M2). All semen samples were preserved at 4°C for 4 days (D0-D4) and are evaluated every 24 hours. The semen evaluation parameters observed are motility, viability, abnormality, and plasma membrane integrity. The results show no significant changes of semen quality on D) (P>0.05). In general, experimental groups supplemented with melatonin showed better results as compared to the control. The supplementation of melatonin is able to protect and maintain the quality of chilled ram semen. Based on this study, results show that A + M0.5 is the best melatonin concentration addition to the AndroMed diluent, as indicated by higher values of the evaluated parameters when compared to the other experimental groups., Stres oksidatif selama pengolahan semen menyebabkan kerusakan membran plasma spermatozoa, mengakibatkan penurunan motilitas dan penurunan plasma membran utuh. Melatonin merupakan antioksidan yang efektif untuk menetralkan spesies oksigen reaktif dan merangsang aktivitas enzim antioksidan untuk melindungi sel spermatozoa. Penelitian ini bertujuan mengevaluasi pengaruh penambahan melatonin pada pengencer AndroMed terhadap kualitas semen cair domba yang disimpan pada suhu 4°C. Koleksi semen dilakukan dengan metode vagina buatan, kemudian semen dievaluasi secara mikroskopis. Semen dengan motilitas sebesar ≥70% diencerkan pada kelompok AndroMed (A), AndroMed dengan melatonin 0.5 mM (A + M0.5), AndroMed dengan melatonin 1 mM (A + M1), AndroMed dengan melatonin 2 mM (A + M2). Semen cair disimpan selama 5 hari (H0–H4) pada suhu 4 °C, kemudian dievaluasi kualitas semen setiap 24 jam. Parameter evaluasi semen berupa motilitas, viabilitas, abnormalitas, dan membran plasma utuh spermatozoa. Hasil penelitian menunjukkan kualitas semen cair tidak berbeda signifikan (P>0.05). Secara umum, penambahan melatonin memiliki hasil nilai yang lebih baik daripada kontrol. Penambahan melatonin mampu melindungi dan mempertahankan kualitas semen cair domba. Berdasarkan hasil penelitian, kelompok pengencer A + M0.5 adalah perlakuan terbaik yang ditunjukkan dengan nilai dari parameter lebih tinggi daripada perlakuan lainnya.
Keyword: Andromed, Antioxidant, Melatonin, Ram, Spermatozoa

Judul: Analysis of Unequal Income Distribution with Cobb-Douglas Production Function
Abstrak: This paper studies the economic growth model by Moav (2002). Moav model shows the existence of unequal income distribution between low-income with high-income community. That kind of unequal income distribution is caused by uneven distribution of income. On this Moav model, there is one area called the threshold. Threshold becomes a benchmark to determining whether a society is categorized into low- or high- income community. The production function used in this paper is the Cobb-Douglas function. The dynamics of this model is described as difference equation of low-income, threshold, and high-income community. Simulation study on the model is carried out using Maple 13 and Mathematica 7.0 software. Overall, from the observed case, high-income community will reach a stable condition earlier, followed by the threshold, and then the low-income community.
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