Judul: Production Management of Peperomia (Peperomia sp.), Begonia (Begonia sp.), Bromelia (Neoregelia schultesiana), and Hortensia (Hydrangea macrophylla) in PT Melrimba Mitra, West Java
Abstrak: Kegiatan magang dilaksanakan pada bulan Maret – Juli 2021 di PT. Melrimba Mitra, Kab. Bogor, Jawa Barat. Kegiatan magang bertujuan untuk meningkatkan pengalaman, wawasan, serta kemampuan teknis dalam pengelolaan tanaman hias khususnya peperomia, bromelia, begonia sebagai tanaman hias pot dan hortensia sebagai tanaman hias lanskap. Kegiatan teknis pengelolaan tanaman hias mencakup jadwal produksi mulai dari persiapan tanam hingga siap panen dan kriteria panen tanaman. Pengamatan tanaman Peperomia obtusifolia, Neoregelia schultesiana, dan Hydrangea macrophylla meliputi jumlah daun dan tinggi tanaman. Pengukuran tanaman Peperomia argyreia dan Peperomia caperata meliputi jumlah tunas. Pengukuran Begonia ‘orococo’ meliputi panjang daun, lebar daun, dan jumlah daun. Kegiatan budi daya tanaman hias yang dilakukan meliputi persiapan media tanam, pembibitan, penyiraman, pemupukan, pengendalian hama penyakit, panen, dan pascapanen. Hasil pengamatan pada tanaman Peperomia obtusifolia, Neoregelia schultesiana, dan Begonia ‘orococo’ yang menggunakan metode perbanyakan setek batang tergolong cepat sehingga selama periode magang tanaman tersebut memenuhi kriteria perusahaan, sedangkan Peperomia caperata dan Peperomia argyreia yang diperbanyak dengan menggunakan metode setek daun memiliki pertumbuhan yang lambat sehingga selama periode magang tanaman tidak memenuhi kriteria panen perusahaan. Hydrangea macrophylla memiliki umur panen rata-rata sekitar 15 MST sehingga periode pengamatan selama 8 minggu tidak dapat mengamati tanaman sampai panen. Hasil analisis usahatani dengan asumsi luasan 200 m2 beserta greenhouse lengkap dan manajemen yang sudah ada pada Peperomia obtusifolia, Peperomia argyreia, Peperomia caperata, Begonia ‘orococo’, dan Neoregelia schultesiana menghasilkan pendapatan yang lebih tinggi dari pengeluaran., The internship activities was carried out in March – July 2021 at PT. Melrimba Mitra, Bogor, West Java. The aims of the internship is to increase experience, knowledge, and skills in production management in ornamental plants, particularly of peperomia, bromelia, begonia as ornamental pot plant and hortensia as ornamental landscape plant. The technical activities in production management including production schedule from planting preparation until they are ready to harvest and fulfil the harvest criteria. Growth measurement on Peperomia obtusifolia, Neoregelia schultesiana, and Hydrangea macrophylla included number of leaves and plant height. Growth measurement on Peperomia caperata and Peperomia argyreia included number of shoots. Growth measurement on Begonia ‘orococo’ included the length of leaf, width of leave, and number of leaves. Cultivation activities include preparation of planting media, nurseries, watering, fertilizing, controlling pests and diseases, harvest, and post-harvest. The results of observation on Peperomia obtusifolia, Neoregelia schultesiana, and Begonia ‘orococo’ using stem cuttings propagation method which is relatively fast so that during internship period the plants met the company’s harvest criteria, while Peperomia caperata and Peperomia argyreia propagated using the leaf cuttings method had slow growth. So that during the internship period the plants did not meet the company’s harvest criteria. Hydrangea macrophylla has an average harvest age of about 15 WAP so that the observation period of 8 weeks cannot observe the plant until harvest period. The result of farming analysis using 200 m2 assumption area with complete greenhouse and existed management of Peperomia obtusifolia, Peperomia argyreia, Peperomia caperata, Begonia ‘ orococo’, and Neoregelia schultesiana produce more income than the output.
Keyword: harvest criteria, leaf cuttings, ornamental landscape plant, ornamental pot plant, stem cuttings

Judul: Manajemen Produksi dan Pascapanen Daun Potong Asparagus  umbellatus Link, Philodendron xanadu Croat, Mayo & J.Boos, dan Phlebodium aureum (L.) J. Sm. di Kwekerij Figaro B.V., Naaldwijk, Belanda Selatan
Abstrak: Kegiatan magang dilaksanakan di Kwekerij Figaro selama empat bulan, mulai 1 Maret hingga 31 Juni 2023. Kegiatan magang bertujuan untuk meningkatkan pengetahuan dan keterampilan mahasiswa secara teknis dan manajerial khususnya dalam budidaya, penanganan panen dan pascapanen daun potong Asparagus umbellatus, Philodendron xanadu, dan Phlebodium aureum yang terdapat di Kwekerij Figaro. Metode yang digunakan dalam kegiatan magang adalah metode langsung dengan melakukan pengamatan secara langsung di lapang serta mengikuti semua kegiatan teknis budidaya tanaman hias daun mulai dari penanaman sampai pascapanen. Metode tidak langsung dilakukan dengan mempelajari data sekunder, berupa arsip perusahaan, laporan perusahaan dan studi psustaka. Berdasarkan hasil kegiatan magang diketahui bahwa tanaman hias daun dibudidayakan di dalam greenhouse agar dapat disesuaikan dengan suhu optimal dan kondisi pertumbuhan untuk tanaman. Total luas lahan greenhouse perusahaan seluas 21.200 m², dengan pembagian area produksi Asparagus umbellatus seluas 8.800 m² (41,5%) dapat memproduksi hingga sebanyak 86.650 tangkai dalam periode 1 bulan, Philodendron xanadu sebesar 1920 m² dapat memproduksi hingga sebanyak 50.480 tangkai dalam periode 1 bulan, dan Phlebodium aureum sebesar 480 m² dapat memproduksi hingga sebanyak 12.200 tangkai dalam periode 1 bulan. Setelah panen, daun potong disimpan dalam cooling room pada suhu 12℃. Kualitas daun potong yang dihasilkan oleh Kwekerij Figaro serta rantai pemasaran yang baik membuat 99,40% produksi dapat dipasarkan. Setelah mengikuti kegiatan magang ini, mahasiswa mendapat keterampilan teknik budidaya, panen dan pasca panen khususnya penentuan kriteria panen, pembuatan buket Asparagus umbellatus dan alur produksi ketiga spesies daun potong., The internship was conducted at Kwekerij Figaro for four months, from March 1 to June 31, 2023. The internship aimed to improve students' knowledge and skills technically and managerially, especially in cultivation, harvest handling and postharvest of cut foliage of Asparagus umbellatus, Philodendron xanadu, and Phlebodium aureum at Kwekerij Figaro. The method used in internship activities was direct method by making direct observations in the field and following all technical activities of leaf ornamental crop cultivation from planting to postharvest. The indirect method is carried out by studying secondary data, in the form of company archives, company reports, and literature studies. Based on the results of internship activities, it is known that ornamental plants are cultivated in the greenhouse to provide optimal temperature and growing condition for the crops. The total area of the company's greenhouse is 21.200 m², with the division of Asparagus umbellatus production area of 8.800 m² (41,5%) can produce up to 86.650 stems, Philodendron xanadu of 1.920 m² can produce up to 50.480 stems, and Phlebodium aureum of 480 m² can produce up to 12.200 stems, all in a period of 1 month. After harvesting, cut leaves are stored in a cooling room at 12°C. The good quality of cut leaves produced by Kwekerij Figaro and a good marketing chain make 99,40% of production marketable. After participating in this internship, students obtained skills in cultivation, harvesting and post-harvest techniques, specifically in determining harvesting criterias, Asparagus umbellatus bouquet making and production flows of the three species of cut foliage.
Keyword: cut foliage, leaf ornamental crop, greenhouse, production

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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