Judul: Effect of Maturation Stages and Seed Position within a Fruit of Sugar apple (Annona squamosa Linn.) on Seedling Performance by Optimizing the Use of Plant Growth Promoting Rhizobacteria (PGPR
Abstrak: Benih srikaya yang bermutu sangat diperlukan untuk mendukung pengembangan bibit tanaman srikaya. Penelitian ini bertujuan menentukan tingkat kemasakan dan posisi benih dalam buah yang tepat guna mendapatkan benih bermutu dan mendapatkan perlakuan terbaik untuk meningkatkan performa bibit melalui penggunaan rizobakteri dan CaCO3. Percobaan pertama menggunakan rancangan acak lengkap (RAL) dua faktor dengan faktor pertama adalah warna kulit buah dan faktor kedua adalah posisi benih dalam buah. Percobaan kedua menggunakan RAL dengan rizobakteri, CaCO3, dan kombinasi keduanya sebagai faktor tunggal. Waktu hitungan pertama pengamatan daya berkecambah pada 36 hari setelah tanam (HST) dan hitungan akhir pada 56 HST. Kualitas benih terbaik diperoleh dari warna kulit buah kuning berdasarkan bobot kering benih, daya berkecambah, indeks vigor, bobot kering kecambah normal, dan kecepatan tumbuh benih. Vigor tumbuh benih tertinggi diperoleh dari buah dengan warna kulit kuning dari bagian ujung dan pangkal buah. Perlakuan CaCO3mempengaruhi pemanjangan akar, lebar daun, diameter batang, dan panjang daun. Aplikasi CaCO3 memberikan pengaruh terbaik terhadap pertumbuhan bibit diikuti dengan perlakuan Pseudomonas + Actimomycetes + CaCO3.
Keyword: Annona squamosa, batang bawah, hitungan akhir, indeks vigor,  rizobakteri, Annona squamosa, batang bawah, hitungan akhir, indeks vigor, rizobakteri

Judul: Induksi Pembungaan dan Perbaikan Mutu Buah Srikaya Jumbo (Annona squamosa L.)
Abstrak: Sugar apple (Annona squamosa-Annonaceae) is one of favorite local fruits. The main constraint in increasing fruit production is low flower production and dichogamy in which male and female reproductive organ did not mature at the same time. The objectives of this research were to increase flower production by pruning and to improve fruit quality by pollination. The research was conducted in Pakem, Sleman, North Yogyakarta in February until July 2013. The research consisted of two experiments, both were arranged in randomized complete block design with one factor. The factor for the first experiment was pruning i.e. total pruning, partial pruning, and unprunned as control. The second experiment was started with observation on flowering phenology from appearance of flower buds to anthesis, and continued on the receptive period of stigma. Following the observation pollination in which three types of pollination was employed, i.e. controlled pollination, natural pollination, and modified natural pollination. The result of the first experiment showed that flowering increased by total pruning up 83.3% and by partial pruning up to 41.8% compared to unprunned trees. The fruit yield from totally prunned trees was 5%, partially prunned was 3.9%, and unprunned was 2.2% of the flower bud appearance. Observation on flowering phenology showed that development of flower bud appearence until anthesis took 25-34 days. The receptivity of the stigma occurred twice during 05.00 am - 14.00 pm and 17.00 pm - 02.00 am. Controlled pollination resulted in 90 % fruit set as compared to 70 % fruit set in natural and modified natural pollination. Controlled pollination produced more symetrical fruit, ranged 136.8-287.8 g, natural pollination ranged 150.0-367.8 g. Modified natural pollination produced the smallest fruit ranged 82.0-235.2 g.
Keyword: sugar apple, stigma receptivity, pollination, pruning, dichogamy

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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