Judul: Diversity of Tilapia Oreochromis niloticus fry with Twice Sorting
Abstrak: Tilapia Oreochromis niloticus is one of the important, especially freshwater, aquaculture commodity in Indonesia. The main obstacle in developing tilapia culture in Indonesia is the insufficient amount of tilapia fry. The problem lies on the quality of the produced fry. Fry quality includes genetic factor, precise harvest time, and precise size (equality of size). Generally speaking, the more fry having equal size the better their qualities are. This research aimed to observe the diversity of standard length (body length) and weight of tilapia fry with twice sorting. This research is divided into three cases, 1 control, and cumulative of all cases. Observed parameters are survival rate, standard length, weight, and the diversity of standard length and weight of tilapia fry. Sorting was carried out at the first and second month and cumulative can increase the average standard length and decrease the variance. Average standard length and diversity increased again on the next month. After three months rearing, standard deviation and CV of weight on control is relatively higher than fry population on all cases and cumulative.
Keyword: 

Judul: Keragaan ikan nila BEST Oreochromis niloticus hasil seleksi di karamba jaring apung Danau Lido, Bogor
Abstrak: The strain BEST (Bogor Enhanced Strain Tilapia) is a new strain of tilapia developed from the sixth generation of GIFT (Genetic Improvement of Farmed Tilapia). Genetic environmental test of BEST has been done in various environment, one of them is in Lido lake. The objective of this research is to evaluate some commercial parameters (growth, SR, etc.) 9 families of BEST in experimental floating net cages. This research was conducted using 27 days-old fry, feeding with 10% of biomass daily for 60 days. Every family reared in floating net cage with density of 60 fish/m3. Observation data of weight, length and survival rate (SR) were collected every 10 days by sampling 50 fish from each family. The result showed that, the family 9 gave the highest growth rate. The family 9 had the highest daily growth rate, both in term of weight and length. Family 7 has varied in parameter observed value. The family 3 provided the highest SR and biomass. The results of this research shown that the population of family 3 had the highest production level. The study is also showed that the real heritability value is 0.009. This study recommend that the family 3 could be use as the candidate in the further selective breeding program.
Keyword: 

Judul: Perkiraan paparan radiasi eksternal dari pemakaian beton ringan aerasi hebel untuk bahan bangunan
Abstrak: Telah dilakukan perhitungan paparan radiasi gamma dari salah satu bahan bangunan yaitu beton ringan aerasi Hebel buatan P.T. Hebel Indonesia, Karawang Timur. Perhitungan yang dilakukan meliputi pengukuran konsentrasi radionuklida alam Ra-226, Th-228 dan K-40, pengukuran koefisien absorbsi dan perkiraan dosis radiasi gamma dari beton ringan aerasi Hebel. Konsentrasi radionuklida alam Ra-226, Th-228 dan K-40 diukur dengan menggunakan Spektrometer Gamma. Kandungan konsentrasi radionuklida alam Ra -226 pada Hebel sebesar (25,11 ± 0,32) Bq/kg. Konsentrasi Th-228 sebesar (31,82 ± 0,41) Bq/kg. Konsentrasi K-40 sebesar (28,28 ± 0,29) Bq/kg. Konsentrasi radionuklida alam Ra-226, Th-228 dan K-40 dari hasil penelitian ini bila dibandingkan dengan data dari hasil penelitian konsentrasi radionuklida alam di dalam bahan bangunan lainnya yang digunakan di Surabaya, Jakarta dan sekitarnya jauh lebih kecil. Pada pengukuran koefisien absorbsi, pada saat sumber radiasi dari luar dipancarkan langsung pada detektor (tanpa Hebel) menghasilkan laju cacah yang lebih besar dibandingkan setelah dipasang Hebel diantara sumber dan detektor. Hal ini dikarenakan sebagian radiasi yang dipancarkan sumber diserap oleh Hebel. Paparan radiasi gamma dari perhitungan didapatkan nilainya sebesar 0,25 mSv/tahun. Nilai ini jauh lebih kecil dibandingkan paparan radiasi gamma dari bahan bangunan yang dilaporkan oleh UNSCEAR tahun 2000 yaitu sebesar 0,41 mSv/tahun. Jadi, Hebel aman digunakan untuk bahan dinding bangunan baik rumah maupun gedung-gedung perkantoran karena paparan radiasi gammanya kurang dari harga standar yang direkomendasikan oleh Komisi Internasional Perlindungan Bahaya Radiasi (International Commision on Radiological Protection/ICRP) yaitu 1 mSv/Th.
Keyword: