Judul: Desain dan Kinerja Ditcher untuk Pembuatan Parit pada Budi Daya Kedelai Jenuh Air di Lahan Pasang Surut
Abstrak: Budi daya jenuh air (BJA) merupakan suatu sistem budi daya yang dikembangkan di lahan pasang surut Indonesia yang terbukti meningkatkan produktivitas kedelai (Glycine max L. (Merr.)) dibandingkan dengan budi daya konvensional. Dengan BJA, air dipertahankan di dalam parit antar bedengan dari awal tanam sampai dengan tanaman dewasa. Kondisi sekarang pembuatan parit dilakukan dengan menggunakan cangkul dan sebagian ada yang menggunakan bajak singkal yang dioperasikan bolak-balik untuk satu alur parit. Kondisi di lapangan juga menunjukkan bahwa kualitas saluran (lebar dan kedalaman saluran, jumlah, serta letak saluran) belum sesuai dengan anjuran. BJA kedelai memerlukan suatu alat pembuat parit yang menghasilkan profil saluran yang sesuai dan dapat bekerja dengan baik di lahan rawa pasang surut. Hipotesis dari penelitian ini adalah bahwa terdapat kemungkinan untuk mendesain dan membangun suatu alat pembuat parit (ditcher) untuk BJA kedelai. Tujuan dari penelitian ini adalah mendesain dan menguji kinerja prototipe ditcher untuk budi daya kedelai jenuh air. Hasil penelitian ini dapat memberikan solusi kepada masyarakat khususnya petani yang berbudidaya kedelai jenuh air dalam upaya peningkatan produktivitas dan mekanisasi budi daya kedelai. Penelitian ini juga dapat memberikan masukan pada industri mesin pertanian berupa desain ditcher untuk pembuatan parit pada BJA kedelai. Tahapan penelitian yang dilakukan dimulai dengan identifikasi masalah. Dari hasil identifikasi masalah akan dimunculkan kriteria desain yang diterjemahkan ke dalam konsep desain. Selanjutnya dilakukan analisis desain untuk pembangunan beberapa prototipe. Prototipe-prototipe tersebut kemudian dievaluasi untuk mendapatkan prototipe terbaik dan diuji kinerjanya. Kriteria desain yang harus dipenuhi yaitu: (1) parit yang terbentuk berukuran lebar 30 cm dengan kedalaman 20 cm; (2) sumber tenaga penggerak berasal dari traktor 2- roda; (3) pembuatan alur parit dilakukan dalam satu kali lintasan. Data tanah telah diambil pada tanggal 20 Agustus 2016 di lahan budi daya kedelai jenuh air yang berlokasi di Jabung Timur, Jambi, Indonesia. Padi dan kedelai merupakan tanaman utama dengan pola tanaman rotasi padi-kedelai. Sampel tanah diambil menggunakan soil sample ring untuk menentukan kadar air dan kerapatan isi tanah. Tahanan penetrasi diukur menggunakan penetrometer, dan parameter tanah kohesi dan adhesi diukur menggunakan aparatus direct shear test. Karakteristik tanah pada lahan tersebut antara lain: kelas tekstur liat berdebu (liat, debu, pasir : 48%, 47%, 5%); batas plastis 35.1%; indeks plastisitas 32.1%; kadar air tanah 65.5 s.d. 68.1%.bk; bulk density tanah 12.7 s.d. 14.6 kN m-3; tahanan penetrasi 116 s.d. 137 kPa; kohesi 23.9 kPa; sudut gesakan dalam 37.2°; adhesi 7.3 kPa; sudut gesakan tanah baja 12.9°. Didapatkan tiga konsep desain yang direncanakan. Desain sayap pada ditcher I mirip dengan sayap bajak singkal. Desain ditcher II menggunakan desain seperti pada ditcher I dengan penambahan sayap bantu pada bagian sayap utama, sedangkan ditcher III menggunakan desain seperti pada ditcher II dengan penambahan ditcher kecil pada bagian depannya. Gaya draft yang bekerja pada ditcher didekati dengan rumus model prediksi gaya yang bekerja pada bajak singkal dari Godwin & O’Dogherty. Telah dibangun kalkulator untuk menghitung prediksi draft dan kebutuhan daya dari ditcher. Kondisi pengoperasian saat perhitungan antara lain:  = 13.43 kN m-3, ϕ = 37.18°, δ = 12.90°, c = 23.91 kN m-2, dp = 0.03 m, ds = 0.17 m, wp = 0.0075 m, ws =
Keyword: budi daya jenuh air, ditcher, kedelai, parit, tanah terganggu

Judul: Rancang Bangun Ditcher Berpengeruk untuk Pembuatan Saluran Drainase pada Budidaya Tebu Lahan Kering
Abstrak: One factor determining the sugar cane production is a good drainage system. The drainage channel that crosses the planting rows is used to drain the excess water from sugar cane plantation. The drainage channel at PG. Jatitujuh has been being formed by using a rotary ditcher. Shape and dimension of the drainage channel were good enough as expected, but the rotary ditcher itself had some disadvantages such as: its blades became dull and worn quickly, it tend to break the tractor PTO system. On the other hand, the utilization of a furrower in the ditch forming is preferred. But, the resulted shape and dimension channel was not good enough. The soil dug out from the ditch covered both sides of the planting rows along the channel. Consequently, it blocked the drain water flow out from the planting rows. The objective of the research was to design a ditcher equipped with a pair of scrappers pulled by a four-wheel tractor. The ditcher operated without using PTO. It’s designed to produce drainage channel with trapezoidal shape with the lower side of 35 cm, upper side of 90 cm, and depth of 40 cm. It is also able to place the dug soil on the top of initial ridges. The prototype of the ditcher was equipped by a pair of soil scrappers. The function of the ditcher is to make the drainage channel, whereas function of the scrapper is to scrap the soils in between the ridges and put it on the top of the ridges. Scrapping mechanism was driven by a front wheel that rolls on the ridge’s profile. The drive force then was transmitted through a transmission shaft to drive the scrapper. The structure of the scrapper ditcher consisted of a frame, a ditcher, and a pair of scrappers. The frame had a triangular shape and equipped with three standardized hitching points. The ditcher had share cutting angle of 70o, 60 cm in cutting width, share intersection angle of 15o, and the concaveness radius of the mold of 65 cm. The construction of the scrapper driver consisted of front wheel (41 cm in diameter), wheel arm (28 cm in length) and the scrapper blade (40 cm x 55 cm in size), scrapper arm (68 cm in length). The dimension of the scrapper ditcher was 173 cm in length, 293 cm in width, and 138 cm in height, and the weight is 435 kg. The modified scrapper ditcher operated successfully. The ditcher produced the expected trapezoidal type drainage channel with a proper size. The test result at Experimental Field of Leuwikopo showed that the length of lower side, upper side and the depth of the ditcher were 39.1 cm, 113.1 cm and 33.1 cm respectively. Whereas, the test result at PG. Jatitujuh showed that the length of lower side, upper side and the depth of the ditcher were 37.9 cm, 100.2 cm and 38.7 cm respectively. The scrapper could scrap the discharged soils and then placed the soils on the ridges. However, there was un-scrapped soil in between the ridges which has 6 cm
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Judul: Characterization Of Psen2 Gene Of Amyloid Disorder Of Alzheimer's Disease In Macaca Fascicularis
Abstrak: Presenilin2 (PSEN2) genes are the primary component of γ-secretase, responsible for the amyloid precursor protein sequence of proteolytic cleavage and the subsequent formation of amyloid β peptides. 18 RNA samples from the brain cortex and hippocampal regions of an adult group (10-12 years old); 4 female) and an old group (>15 years old; 5 females) of Cynomolgus monkey (Macaca fascicularis) were analyzed using RT-qPCR. There were no differences in PSEN2 mRNA expression in the cortex in between groups (p=0.063). There were significant differences in mRNA expression in the hippocampus in between groups (p= 0.010). The overall PSEN2 expression level was higher in the adult monkey group and correlated early onset Alzheimer’s disease (EOAD) characteristics in relatively young individuals. The overall PSEN2 expression level was low in the old monkey group. High PSEN2 expression in an adult group might correlate with the regulation of neuronal plasticity, amyloid precursor protein processing, and tau aggregation. It was increased in PSEN2 expression correlated with learning and memory impairment in the cortex and hippocampus. Alteration in PSEN2 expression may be a risk factor for Alzheimer’s disease. This study proposes that PSEN2 informational mutations could be included as useful gene biomarkers for the comprehensive prognosis of Alzheimer's disease in the Omnibus Gene Expression (GEO) database.
Keyword: cortex, Cynomolgus monkey, EOAD, hippocampus, PSEN2, RT-qPCR