Judul: Tinjauan Matematis pada Model Makroskopik dan Mikroskopik Arus Lalu-lintas
Abstrak: Traffic flow phenomenon can be described through mathematical model such as continuous dynamic model with an ordinary differential equation so that it can be solved with integral factors. In this paper three simple models of traffic flow are discussed, i.e, two macroscopic and one microscopic models. Macroscopic model formulates dynamics of the traffic flow that occurs on a large number of vehicles on a road. While the microscopic model explains drivers’ behavior in their interaction with other vehicles ahead, i.e, car-following model. This paper shows the existence of ordinary differential equation found in the traffic flow model and indicates some different representations in the context of the same model. It also reviews a simple model of traffic flow along a single link, which leads to some unexpected results, i.e, it can express the solution model in term of link outflows as well as trip time. In the microscopic model, simulation is done to illustrate the behavior of the drivers with a sensitivity coefficient as a benchmark parameter.
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Judul: Analisis Sistem Dinamik Lalu Lintas dengan Model Mobil Pengikut
Abstrak: A mathematical model can be formulated to study and solve certain real problem, such as traffic problem. In this manuscript, a nonlinear car-following model that includes a reaction-time delay of drivers in a circular road was discussed and the analysis of its linear stability was performed. Moreover, the characteristic equation on equilibrium state was investigated. Based on the uniformly flow solution, boundaries of Hopf bifurcations were determined in the complex parameter space. Furthermore, a simulation on traffic dynamics was also performed. The simulation result shows that there exists a slight change of linear stability, when the sensitivity parameter changes
Keyword: Bogor Agricultural University (IPB), time delay., stability analysis, Hopf bifurcation, car-following model

Judul: Profil Imunoglobulin G Pada Kambing Peranakan Etawah Bunting Yang Diberi Mineral Zink (Zn).
Abstrak: Penelitian ini bertujuan untuk mengetahui efek suplementasi mineral Zn terhadap profil imunoglobulin G (IgG) pada kambing Peranakan Etawah (PE) bunting periode sekitar partus. Penelitian ini menggunakan lima belas ekor kambing umur tiga sampai enam tahun, dengan bobot badan 30 sampai 50 kg. Induk kambing dibagi ke dalam tiga kelompok perlakuan, masing-masing terdiri atas 5 ekor. Kelompok Zn40 (kontrol) diberi pakan mengandung Zn 40 ppm, kelompok Zn60 mengandung Zn 60 ppm, dan kelompok Zn80 mengandung Zn 80 ppm. Pengambilan sampel darah dilakukan pada vena jugularis setiap dua minggu, mulai umur kebuntingan dua belas minggu sampai dengan delapan minggu setelah partus untuk dilakukan analisis terhadap konsentrasi IgG. Analisis konsentrasi IgG dilakukan menggunakan teknik Enzyme Linked Immunosorbent Assay (ELISA) metode kompetitif. Hasil penelitian menunjukkan bahwa tidak ada perbedaan yang nyata (P>0,05) antar kelompok perlakuan maupun waktu kebuntingan. Namun demikian, terdapat kecenderungan menurunnya konsentrasi IgG pada kelompok Zn40 dan Zn80 pada periode kebuntingan hingga partus, sedangkan pada kelompok Zn60 memperlihatkan konsentrasi IgG yang relatif stabil sepanjang pengamatan. Suplementasi Zn 60 ppm memperlihatkan konsentrasi IgG yang lebih tinggi dibandingkan dengan suplementasi Zn 80 ppm. Suplementasi Zn dalam pakan pada periode kebuntingan dan awal laktasi perlu dilakukan untuk meningkatkan sistem kekebalan tubuh.
Keyword: IgG, peranakan etawah, periparturien, zink