Judul: Pengaruh Inokulum Bacillus thuringiensis terhadap Perubahan Struktur Usus Tengah Ulat Grayak (Spodoptera litura F.)
Abstrak: Bacillus thuringiensis was known as biocontrol agent of cotton leafworm growth. B. thuringiensis isolate produced protein crystal as Cry protein which on alkaline condition caused epitel cell in the midgut of cotton leafworm swelled. The aim of this research was to know the effect of B. thuringiensis inoculum from different subspesies to cotton leafworm and the histopatology change in its midgut. Bacillus thuringiensis subsp. aizawai (Bta), B. thuringiensis subsp. pakistani (Btp), B. thuringiensis 47 (Bt47), and B. thuringiensis Lot 2 (BtL2) were tested to 3rd instar larvae. The structures of its midgut were observed at 0, 24th, 48th, 72nd, 96th and 120th hours. They were preparated by Paraffin method and Hematoxylin-Eosin staining. Generally, all 0 hour treatments showed the similar condition with control which the peritrophic membrane and epithelial cells below were still normal. The peritrophic membrane was dissapear at 24th hours, followed by the swelling of epithelial cells and its cores at 48th till 72nd hours. At 96th and 120th hours, the epithelial cells were lysis and disintegrated. The BtL2 isolate had the highest and fastest damages, followed simultantly by Bta, Bt47, and Btp.
Keyword: Spodoptera litura, midgut, histopathology, acillus thuringiensis

Judul: Efektivitas Protoksin Bacillus thuringiensis subsp. aizawai, Konidia Beauveria bassiana, dan Campurannya terhadap Ulat Grayak Spodoptera litura F.
Abstrak: Armyworm or (Lepidoptera:Noctuidae) is one of main pest in plant crop. This pest might cause damage on the leaves and stems and reduce of crop production. Bacillus thuringiensis subsp. aizawai and Beauveria bassiana have been known as biocontrol agent to this pest. This research was aimed to observe the production time of B. thuringiensis subsp. aizawai toxin, measure the effect of toxin against Be. bassiana conidia, to test the activity of toxin, conidia and their mixture against S. litura. B. thuringiensis subsp. aizawai was grown on specific medium for B. thuringiensis. Toxin production of the isolate was measured every 4 hours up to 48 hours incubation. Be. bassiana was grown on the white rice medium and its conidia was grown on the Potato Dextrose Agar medium containing toxin. The activity test of toxin B. thuringiensis, Be. bassiana conidia, and their mixture was done by spraying them to S. litura larvae. The stasionary phase of B. thuringiensis was obtained at 16 hours incubation and the maximal toxin production at 48 hours. The highest mortality of S. litura larvae caused by toxin activity was 63.3% at 48 hours incubation. The highest mortality caused by conidia infection activity was 80% at the concentration of 108 conida ml-1. The highest mortality caused by their mixture was 96,7%.
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Judul: Investment Risk Estimation with Monte Carlo Simulation Method on Renewable Energy Sector Stock Portfolio
Abstrak: Analisis risiko penting dalam kegiatan investasi saham, terutama di sektorsektor potensial seperti energi terbarukan. Value at Risk (VaR) dan Expected Shortfall (ES) adalah ukuran untuk menunjukkan tingkat risiko. Penelitian ini bertujuan untuk mengestimasi VaR dan ES menggunakan simulasi Monte Carlo berdasarkan data harga saham harian mulai tanggal 1 April 2020 sampai dengan 31 Maret 2021. Pengukuran VaR dan ES pada portofolio yang dibentuk dengan metode Mean-Variance Efficient Portfolio menunjukkan nilai yang lebih kecil daripada saham tunggal. Komposisi saham tersebut terdiri dari FSLR 64,35%, REGI 27,96%, dan SEDG 7,69%. Uji validitas model estimasi VaR dilakukan dengan menggunakan metode Kupiec Test. Hasil pengujian validitas menunjukkan bahwa nilai VaR portofolio dengan simulasi Monte Carlo akurat untuk mengestimasi tingkat risiko suatu investasi.
Keyword: Expected Shortfall, Monte Carlo simulation, Value at Risk