Judul: Hubungan linear antara bilangan fibonacci, bilangan lucas dan golden section di himpunan bilangan real tak negatif
Abstrak: Leonardo of Pisa (Fibonacci), pada tahun 1202 menemukan barisan bilangan yang diperoleh dari bertambahnya jumlah pasangan kelinci tiap bulan. Kelinci tersebut diasumsikan hidup selamanya. Bilangan pada barisan tcrscbut empat abad kemudian oleh Kepler dinyatakan dalam rumus rekursif berikut: F(0) = 0, F(I) = I, F(n+2)=F(n) + F(n+I), dengan n = 0, I, 2, ..... Oleh Eduard Lucas, bilangan pada barisan tersebut diberi nama Bilangan Fibonacci. Kemudian Lucas menemukan barisan bilangan yang mirip dengan bilangan Fibonacci, yaitu : L(0) = 2, l(I) = I, l(n+2)=l(n) + l(n+I), dengan n = 0, I, 2, .... lebih dari ernpat puluh persamaan yang menyatakan hubungan linear antara bilangan Fibonacci, bilangan Lucas dan Golden Section. Sebagian besar dapat dibuktikan dengan prinsip induksi matematika dan aljabar di himpunan bilangan real.
Keyword: Fibonacci numbers, number line, mathematical induction

Judul: Determinan dan Invers Matriks Skew Left Circulant dengan Entri  Bilangan Fibonacci
Abstrak: Matriks skew left circulant adalah suatu matriks persegi dengan entri baris bergeser satu kolom secara berurutan ke kiri dan semua entri yang berada dibawah diagonal sekunder akan bernilai negatif, sehingga untuk mengetahui seluruh matriks skew left circulant dapat dilihat dari salah satu baris dari matriks tersebut. Entri-entri dari skew left circulant dapat menggunakan entri dengan berbagai barisan bilangan, salah satunya adalah dengan barisan bilangan Fibonacci. Pada karya ilmiah ini diformulasikan determinan dan invers matriks skew left circulant dengan entri bilangan Fibonacci. Pembuktian Formulasi determinan matriks skew left circulant diperoleh dari penerapan serangkaian operasi baris dasar pada matriks skew circulant sehingga diperoleh matriks segitiga atas, dilanjutkan mengalikan dengan determinan matriks Gamma. Sedangkan, formulasi inversnya diperoleh dengan membuat matriks-matriks dari matriks skew circulant representasi dari hasil serangkaian operasi baris dasar dan operasi kolom dasar, dilanjutkan dengan mengalikan dengan invers matriks Gamma., The left circulant skew matrix is a square matrix with row entries shifted one column sequentially to the left and all entries under the secondary diagonal will be negative, so to find out the entire circulant skew left matrix can be seen just from the first row of the matrix. Entries from the skew left circulant can be filled in various number sequences, one of which is the Fibonacci number sequence. In this scientific work, the determinants and inverses of the skew left circulant matrix are formulated with Fibonacci number entries. Proof The formulation of the skew left circulant matrix determinant is obtained from applying a series of basic row operations to the circulant skew matrix so that an upper triangular matrix is obtained, followed by multiplying it with the Gamma matrix determinant. Meanwhile, the inverse formulation is obtained by making matrices from a circulant skew matrix representing the results of a series of basic row or column operations, followed by multiplying by the inverse Gamma matrix.
Keyword: Fibonacci number, determinant, inverse, skew left circulant matrix

Judul: Heterologous Expression Of Endo-Β-Xylanase From Bacillus Pumilus Strain Bcrs-01 In Escherichia Coli.
Abstrak: Xylanases are glycoside hydrolase family 11 which depolymerise xylan in the plant cell wall, the most excessive form of hemicellulose. Endo-β-xylanases (EC 3.2.1.8) are most important to breakdown β-1,4-glicoside bond of xylan to produce disaccaride xyloolygosaccaride (XOs) and xylose (monomer). Bovine rumen fluids have potential to obtain endo-β-xylanase produced of bacteria. The objectives of this study were to obtain xylanase producing bacteria and to express xynA gene encoding endo-β-xylanase from bacterium in Escherichia coli. Twenty nine isolate bacteria have been succesfully isolated from bovine rumen fluid in agar medium containing birchwood xylan. Isolate BCRS-01 bacterium was previously screened for the high production of xylanase. Based on 16S rRNA gene sequence analysis, BCRS-01 showed high similarity (99%) to Bacillus pumilus (accession number NR043241). The crude xylanase had optimal activity at 55oC, pH 7.0. Furthermore, the crude xylanase exhibited broad pH stability from 4.0 to 10.0 and remained more than 60% and 40% of its activity after incubation at pH 4.0 until 10.0, respectively for 60 min. It also showed a stability at temperature 25-50oC since it retained 80% and 50% of its activity when incubated at 50oC or 30 and 60 min, respectively. The xylanase activity was strongly inhibited by Ca2+ and Cu2+ at concentration 10 mM, and as little as 1 mM for Mn2+. Therefore, this xylanase has potentially used as additive feeds in animal feed industry. The DNA sequence xynA gene encoded endo-β-xylanase was amplified and cloned into the expression vector pET-15by under the control of T7 promoter. The recombinant protein had succesfully expressed in Escherichia coli BL21 (DE3) pLysS. A protein recombinant of approximately, 26.7 kDa was observed on the SDS-PAGE analysis. Crude extract of recombinant endo-β-xylanase demonstrated activity of enzyme at 56 U mL-1 using birchwood xylan as a substrate at 55oC for 10 min.
Keyword: Bacillus pumilus, bovine rumen fluid, endo-β-xylanase, heterologous expression.