Judul: Pengaruh Pemupukan Boron terhadap Kualitas Buah Manggis (Garcinia mangostana L.).
Abstrak: The objective of this research was to study the effect of boron application on fruit quality of mangosteen, especially the scaring and yellow latex incidence (gamboges). The research was conducted at mangosteen orchard Cicantayan Sukabumi, Laboratory Centre for Tropical Horticulture Studies (PKHT) IPB, and Post Harvest Laboratory of Agronomy and Horticulture IPB on November 2011 to April 2012. The research was arranged in Randomized Complete Design with one factor of treatment: Boron dose (B2O3). There were four doses of fertilizer used consisted of : the control with no fertilizer application B2O3, 15, 30, and 45 g B2O3 / plant. The results of this research showed that Boron application have significant effect on gamboges on pericarp of the mangosteen fruit when compared to controls. However, Boron application significantly increase fruit weight and diameter as well as totat soluble solids content, but there is no different effect of doses between 15, 30, and 45 g/ plant. This treatment is also have no effect on other components of the mangosteen fruit qualities such as hardness of fruit, fruit weight and skin thickness, total of titrable acid, and vitamin C in the mangosteen.
Keyword: 

Judul: Studi aplikasi Kalsium dan Boron terhadap pengendalian getah kuning pada buah manggis (Garcinia mangostana L.
Abstrak: New and exciting developments in research of mangosten yellow latex in the past few years greatly contributed to better understanding of the methode to control gamboge in mangosten fruits. A field experiment was conducted to understanding and quantifying the effect of boron (B) and calcium (Ca) application to control yellow latex or gamboges on manggosten fruit. There are five treatments and one control as follow: (1) no fertilizer applied as control, (2) 5.79 kg Ca.tree-1.year-1 applied by soil application (3) 5.79 kg Ca.tree-1.year-1 applied by soil application + 1.553 g B.tree-1 .year-1 applied by soil application, (4) 5.79 kg Ca.tree-1.year-1 applied by soil application + 0.047 g B.tree-1.year-1 applied by foliar application, (5) 1.553 g B.tree-1 .year-1 applied by soil application, (6) 0.047 g B.tree-1.year-1 applied by foliar application. The experiment was laid out on a randomized complete block design. The treatment of 5.79 kg Ca.tree- 1.year-1 applied by soil application + 1.553 g B.tree-1 .year-1 applied by soil application significantly affect to reduced yellow latex in aril till to 0%, reduced yellow latex scoring in aril, increasing boron content in endocarp. However they were not significant affect on fruit weight, fruit diameter, fruit fluident, total soluble solid (TSS), total acid titrated (TAT), Ca in leaves, Ca in pericarp, B in excocarp, and B in mesocarp.
Keyword: 

Judul: igenvalues and Eigenvectors of Tridiagonal Matrix with Non Constant and Recurrent Diagonal Entries.
Abstrak: Matriks tridiagonal adalah suatu matriks yang mempunyai entri-entri bernilai nol kecuali pada diagonal utama, di bawah diagonal utama (subdiagonal) dan di atas diagonal utama (superdiagonal). Entri pada diagonal utama tidak konstan dan berulang. Setiap entri pada matriks tridiagonal ini adalah bilangan kompleks. Dalam karya ilmiah ini, akan dibuktikan 3 teorema untuk menentukan nilai eigen dengan 2 kasus dan 1 teorema untuk menentukan vektor eigen. Teorema pertama menentukan polinomial karakteristik dari matriks tridiagonal. Polinomial karakteristik dari matriks tridiagonal tersebut digunakan untuk menentukan nilai eigen pada teorema kedua dan ketiga serta menentukan vektor eigen pada teorema keempat
Keyword: