Judul: Kriopreservasi semen kuda dalam pengencer skim dan dimitropoulos dengan dimetilformamid sebagai krioprotektan
Abstrak: Kriopreservasi semen kuda dalam pengencer skim dan dimitropoulos dengan dimetilformamid sebagai krioprotektan.
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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: Model Pertumbuhan Ekonomi Perkotaan Berdasarkan Geografi Ekonomi
Abstrak: In economic activity, economic growth means increasing production of goods and services. Economic geography is economic system with respect to spatial dimension. Rapid economic development and structural changes such as rents, residential area, and transportation systems are indicators of progressivity of a country and its economics. A country is said to progress when the production rate of goods and services are increasing, then the volume of goods and services produced are also increasing from time to time. Neoclassical theory of economic growth depends on the increased the supply of factors of production and the rate of technological progress. The production factors are labor and capital. Domar in 1948 stated that production output is a function of capital. As a result, labor is always combined with capital on fixed proportion. Solow in 1956 added labour as one of the variables of production function. This study aims to examine the dynamics of urban growth model based on economic geography, i.e. study of the economic system based on the location and geographical conditions. The urban economic growth model considers the urban area to be divided into two areas, namely residential area and central business district. Urban area is assumed to have centralized workforce and multi sector economic system. The main economic activity in the central business district is production. On the other hand, consumption and saving activities are carried out in the residential area. More over people need to travel from residential area to the business district in their economic activities. This study will also examine the equilibrium solutions of the model and then give simulation on the model. The results of theoretical study show that the dynamic system of urban economic growth model is formulated in the form of linear system of first order differential equations. The variables which determine economic growth are the accumulation of capital and labor inputs. The equilibrium of these variables can be determined. Capital accumulation shows a pattern that follows an exponential function. Simulation study give the following results. The characteristics of urban economic growth are confirmed by the fact that when the elasticity of the urban industrial sector capital increases, then production output of the two sectors, both industrial and service sector, are increased. The industrial production increases sharply, while the service sector production output is relatively stagnant and then increased with a slower rate compared to the industrial sector. Increased elasticity of capital in industrial sector also tends to increase the income of urban residents, the labor wages, and the capital of both sectors. However, housing consumption tends to fall with increases in industrial sector capital elasticity. Furthermore, simulation results demonstrate the spatial and temporal changes in urban land rental values tend to decrease with increasing distance from the central business district and increasing time. Highest land rent is in a location that has the shortest distance to the central business district. The simulations also show increase in consumption following the increase in distance from the central business district. This suggests that the further away from the business district, the more people who rent or buy housing.
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