Judul: Dynamics Model for Rural and Urban Economic Growth
Abstrak: Lewis theory of structural change has focused on mechanisms that allow countries to transform their domestic economic structure to a more modern economy. The proposed model deals with the mechanism of interaction between rural and urban Economic. This model is concerned with the process of labor transfer from rural to urban areas. This study aims to model the dynamics of economic growth in rural and urban areas, including determining the equilibrium solution and to carry out simulation of the model. The simulation results show that the transfer of labor from rural to urban areas will increase the rate of change of capital so that structural changes can be realized. In addition, increased propensity to save in rural areas will also accelerate structural change
Keyword: 

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.
Keyword: 

Judul: Aktivitas anti-alergi tipe I ekstrak jahe (Zingiber Officinale Rescue) Pada mencit
Abstrak: Penelitian ini bertujuan untuk mempelajari pengaruh ekstrak jahe terhadap perlindungan lisis sel mastosit mencit yang telah tersensitisasi dengan ovalbumin. Ekstraksi jahe dilakukan dengan berbagai pelarut yaitu air, etanol, aseton dan diklorometan. Untuk melihat dan memisahkan komponen ekstrak jahe dilakukan dengan HPLC (High Perfomance Liquid Chromatography) dengan komponen capcaisin dan dihidrocapcaisin sebagai standar eskternal. Berdasarkan hasil pemisahan dengan menggunakan HPLC ternyata komponen ekstrak jahe yang paling banyak teridentifikasi berasal dari ekstrak aseton jahe yaitu sebanyak 6 komponen. Kemungkinan senyawa tersebut adalah 6, 8 dan 10 gingerol; 6,8 dan 10 shogaol. Oleh karena itu untuk uji ketahanan sel mastosit digunakan ekstrak aseton jahe dan ekstrak air jahe. Mencit dibagi menjadi 4 kelompok, kelompok K (kontrol) dan kelompok Ovalbumin (O) diberi minuman air gula 5% w/w sedangkan kelompok Jahe (J) dan (OJ) diberi minuman sari jahe (10% w/w). Pemberian air minum untuk semua kelompok dilakukan secara ad libitum. Untuk proses sensitisasi, kelompok O dan OJ disuntik dengan ovalbumin secara subkutan setiap minggu selama 39 hari serta pada hari ke 30 diberi ovalbumin (2 mg/ml) didalam air minumnya selama 9 hari. Aktivitas anti-alergi tipe I dari ekstrak jahe diuji dengan melihat efek degranulasi dari sel mastosit peritonial mencit yang diinkubasi dengan ovalbumin sebagai alergen. Untuk melihat pengaruh pemberian minuman sari jahe terhadap kemampuan sel mastosit untuk tetap utuh dapat dilihat dari media inkubasi dengan tanpa penambahan ekstrak jahe. Sel mastosit dari mencit yang diberi minuman sari jahe dan disensitisasi (kelompok OJ, 59,63%) ternyata lebih resisten terhadap proses degranulasi bila dibandingkan dengan sel mastosit yang berasal dari mencit yang tidak diberi minuman sari jahe dan disensitisasi (kelompok O, 13,7%). Minuman sari jahe dapat memberikan efek perlindungan terhadap sel mastosit dari proses degranulasi sehingga pelepasan mediator dapat dicegah, dengan demikian reaksi alergi tipe I dapat dihambat. Konsentrasi ekstrak jahe yang ditambahkan pada media inkubasi adalah -25, 50, 100 µg/ml. Konsentrasi terbaik dari ekstrak air jahe dalam melindungi sel astosit dari proses degranulasi untuk mencit yang tidak tersensitisasi dengan valbumin (kelompok K dan J) adalah 25 µg/ml. Sedangkan untuk mencit yang tersentisasi (kelompok O dan OJ) adalah 100 µg/ml.
Keyword: Anti-alergi, Ekstrak jahe