Judul: Persamaan Matematika Untuk Struktur Tegakan Horizontal Hutan Alam Bekas Tebangan Di Areal Kerja Iuphhk-Ha Pt Gunung Gajah Abadi Kalimantan Timur
Abstrak: Struktur tegakan horizontal adalah sebaran jumlah pohon persatuan luas dalam berbagai kelas diameter. Kegiatan pemanenan di hutan alam primer akan meninggalkan struktur tegakan yang bervariasi. Struktur tegakan horizontal di hutan alam primer dapat dimodelkan dengan persamaan matematika menggunakan fungsi eksponensial negatif maupun polinomial. Struktur tegakan hutan alam bekas tebangan 1 tahun, 9 tahun, 20 tahun, dan 29 tahun di areal PT Gunung Gajah Abadi memberntuk kurva “J” terbalik sesuai dengan struktur tegakan di hutan alam primer. Struktur tegakan di hutan alam bekas tebangan memiliki jumlah permudaan yang lebih banyak dibanding hutan alam primer, namun semakin lama umur hutan alam bekas tebangan jumlah permudaaannya semakin sedikit seperi di hutan alam primer.
Keyword: struktur tegakan, hutan alam bekas tebangan, persamaan matematika

Judul: Model struktur tegakan hutan alam di areal kerja IUPHHK-HA PT Gunung Gajah Abadi Kalimantan Timur
Abstrak: Penelitian Model Struktur Tegakan Hutan Alam di Areal Kerja IUPHHKHA PT Gunung Gajah Abadi Kalimantan Timur dilakukan untuk mendapatkan model struktur tegakan hutan alam di areal kerja IUPHHK-HA PT Gunung Gajah Abadi Kalimantan Timur. Pengambilan sampel dilakukan secara purposive sampling untuk mewakili berbagai kelas umur tebangan. Struktur tegakan yang dimaksud dalam penelitian ini adalah struktur tegakan horizontal yaitu sebaran banyaknya pohon pada berbagai kelas diameter. Struktur tegakan hutan alam secara umum berbentuk “J” terbalik yang artinya terjadi penurunan banyaknya individu pohon seiring bertambahnya kelas diameter. Bentuk struktur tegakan hutan alam dapat dijelaskan dengan fungsi peubah acak kontinu yaitu model famili sebaran lognormal dan model famili sebaran eksponensial negatif. Unit contoh dalam penyusunan model dipilih berdasarkan kelas umur tebangan yaitu RKT 2013 (1-5 tahun), RKT 2007 (6-10 tahun), RKT 2003 (10-15 tahun), RKT 1995 (16-20 tahun) dan hutan alam primer. Pemilihan model didasarkan pada nilai kemungkinan maksimum tertinggi dan uji kesesuaian model. Berdasarkan kriteria pemilihan model, model lognormal merupakan model terbaik diantara dua model yang dicobakan meskipun hasil uji kesesuaian model di RKT 2003 dan hutan primer memiliki kerapatan dugaan yang berbeda nyata dengan aktualnya.
Keyword: forest, model, stand structure

Judul: Effectiveness of Microwave Oven against B. cereus to Reach Food Safety Objective in Cook-chill Foods
Abstrak: Cook-chill foods are meal that being cooked and then chilled quickly until further consumption. Usually before being consumed, the foods are reheated by the consumers to improve the organoleptic property and also to destroy bacteria. One of the things that need to be considered is that cook-chill foods that are originated from grains like rice or wheat are vulnerable to be contaminated by pathogen, especially Bacillus cereus. Another problem is that on the packaging of specific cook-chill food that being investigated, there is only instruction manual on how to reheat the food with 1800 W microwave oven. Microwave oven that is being used in household level is usually lower than 1000 W, so there is a possibility under-cooking may happen because there is no standardization on how to heat food with microwave on household level. The research was conducted in five steps, which were; (1) investigation of standard plate count and B. cereus count on two cook-chill foods (spaghetti bolognaise and black pepper chicken rice), (2) challenge test on those cook-chill foods to evaluate the growth of B. cereus on cook-chill food on 15oC, (3) challenge test to evaluate inactivation of vegetative cells and spores of B. cereus by microwave oven (850 watt and 410 watt), (4) to evaluate if FSO of those cook-chill foods could be achieved based on data gathered in the previous results, and (5) to study the effect of microwave oven and moist heat against leakages of nucleic acids and proteins of B. cereus. The results of this research were that microwave oven with 850 watt power could still reach food safety objective (FSO) when cook-chill foods were being reheated for the recommended time on the packagings (45 seconds for spaghetti bolognaise and 2 minutes for black pepper chicken rice), however when using 410 watt microwave oven, FSO could not be achieved. The mechanism of which why microwave oven could destroy vegetative cell and spores of B. cereus was also investigated. The result was that heat treatment using microwave oven differed when compared to moist heat since heat treatment using microwave oven caused leakages of nucleic acid and protein content of the vegetative cells and spores of B. cereusin much larger effect than moist heat.
Keyword: cook-chill foods, Bacillus cereus, microwave, rice, spaghetti, food safety objective