Judul: Regression Analysis For Longitudinal Data
Abstrak: Penelitian ini dilakukan untnk menelaah hubungan antara umur kehamilan dengan berat badan ibu hamil menggunakan metode Generalized Estimating Equations (GEE) dan membandingkannya dengan Metode Kuadrat Tcrkeeil (MKT). Metode GEE digunakan untnk mengatasi masalah ketidakbebasan akibat terkelompoknya data. Data terkelompok dapat terjadi karena adanya pengulangan pengamatan pada setiap k subyek. Data yang dianalisis dalam penelitian ini adalah data kehamilan yang meliputi berat badan ibn hamil sebagai peubah resporl· dan umur kehamilan sebagai peubah penjelas Untuk mengevaluasi keefektifan GEE dibuat simulasi dengan berbagai tingkat korelasi dalam setiap subyek pengamatan. Hasil analisis menunjukkan bahwa metode GEE itu mampu menduga koefisien regresi dengan ragam yang lebih keeH dibandingkan dengan MKT (Metode Kuadrat Terkeeil). Penduga (5 pada GEE terkoreksi ole11 besamya keeratan hubungan dalam ke1ompok atau subjek pengamatan.
Keyword: 

Judul: Penerapan model regresi logistik sebagai analisis faktor risiko pada perempuan hamil terhadap bobot bayi lahir rendah
Abstrak: Kajian ini bertujuan memperoleh model dugaan peluang BBLR bagi perempuan hamil dengan model regresi logistik. untuk menjelaskan faktor-faktor risiko pada perempuan hamil. Data yang digunakan adalah data sekunder hasil pe- nelitian Puslitbang Gizi di Bogor. Sebagai peubah respons digunakan kategori bobot bayi lahir dengan beberapa peubah penjelasnya, yaitu lama kehamilan, usia perempuan hamil, tinggi badan perempuan hamil, dan kategori paritas. Plot proporsi BBLR dan uji formal menunjukkan bahwa lama kehamilan lebih berpengaruh terhadap kategori bobot bayi lahir. Usia dan tinggi badan perempuan hamil diubah. menjadi berskala biner untuk penyederhanaan analisis selanjutnya. Pembentukan model regresi logistik berganda meng- hasilkan peubah penjelas lama kehamilan, kategori paritas, dan kategori tinggi badan. Setelah dilakukan penelusuran sisaan dengan membentuk plot peluang empirik, ternyata model tersebut sudah cukup baik digunakan sebagai model dugaan peluang BBLR. Faktor-faktor risiko tinggi pada perempuan hamil untuk melahirkan bayi dengan BBLR adalah kehamilan kurang bulan, kelahiran anak pertama, dan tinggi badan kurang dari 145 cm.
Keyword: 

Judul: Application of phycocyanin from microalgae Spirulina platensis as light harvesting in anatase TiO2 nanoparticle solar cell.
Abstrak: The dye sensitized solar cell (DSSC) has been assemblied used hybrid titanium oxide (TiO2) film/phycocyanin. The TiO2 film was synthesized by sol gel method with titanium chlorida (TiCl4) as precursor by hydrolysis used sulfuric acid (H2SO4). Furthermore, it calcinated for 2,5 hours in variation of annealing temperature (400oC, 600oC, 800oC, dan 1000oC). In XRD patterns exhibited which annealing temperature at 400oC to 800oC were anatase phase all. When annealed at temperature 1000oC, it caused phase transformation from anatase to rutile. The crystals size according to XRD patterns were 13,75 nm, 20,79 nm, 25,25 nm, 48,88 nm and particle size from SEM images were 43,06 nm, 44,91 nm dan 64,99 nm, 80,40 nm, respectively. The crystals and particle size increased with annealing temperature. The film thickness influenced material absorption. The optical measurement of TiO2 film and TiO2/phycocyanin hybrid film used UV-Vis spectrophotometer. Additional phycocyanin caused peak width of absorbed region from ultraviolet to visible region. The band gap energy of TiO2 can be calculated using the cut off wavelength obtained from the absorbance spectrum of a nanoparticles TiO2 films. Based on intersection between linear and energy (hv) axis. In this study just limited for anatase phase. It was caused anatase band gap is wider than rutile phase. That’s meaningful for solar cell application such as dye sensitized solar cell (DSSC). The absorption coefficient average at difference annealing temperature such as at 400oC, 600oC, 800oC were 8,1600x102, 1,7535x103 and 4,0154x102, where α < 104 include to direct transition. Band gap energy 400oC, 600oC, 800oC were 3,79 eV, 3,59 eV, and 3,35 eV, respectively. Based on this result, exhibition that band gap energy of TiO2 semiconductor film decreased with increasing annealing temperature. Spirulina platensis was cultivated in technical modification (Hastuti) with aeration under light intensity about 3000 lux. The cell density (stationer phase) for eighth day which OD value was more than 0,5. It means, the culture can be harvested. In 80 liters Spirulina platensis culture have been produced biomass dry about 10,46 gram and extracted phycocyanin in dry powders was 5,50 gram. The phycocyanin absorption spectrum at the wavelength of 619,36 nm (visible region) which had relaxation energy was 2,945 eV. The emission peak at the wavelength of 708,55 nm with relaxation energy about 2,793 eV. The Stokes shift based on difference energy absorption and emission calculated about 0,152 eV. Both of this showed phycocyanin can absorbed and radiated the sun light which received. This choice characteristic pigment was a good one related to sensitizer in solar cell application. Integration between light harvesting protein and TiO2 semiconductor surface had important role in improving of output as solar cell materials. The presence of carboxylate group (-COOH) made pigment be more efficient was due to anchored to the surface of TiO2 ampoter. The phycocyanin pigment had carboxylate group which reacted with TiO2 surface formed ester. The carboxylate group increased of dye electronics couple from excited state (p anti bonding orbital) to semiconductor acceptor state (TiO2 conduction band). The samples which made based on annealing temperature variation formed be solar cell respectively. Furthermore, cells be assembled for
Keyword: anatase, dye sensitized solar cell, efficiency, gap energy, phycocyanin