Judul: Perbedaan Toleransi Antara Dua Spesies (Perna Viridis Dan Vasticardium Cf. Flavum) Di Bawah Paparan Stres Termal Dan Hipoksia
Abstrak: The environmental shifting is one major stress to sessile organisms such Bivalves. Two of most vital environmental parameters are temperature and oxygen availability. High water temperature and low oxygen concentration leading to hypoxia conditions will affecting the performance of Perna viridis and Vasticardium cf. flavum. Hypoxia (DO 0,5 mg/l) significantly causing stress to both species (pperna < 0,01; pvasticardium < 0,01), and P. viridis has higher tolerance to hypoxia compare to V. cf. flavum (p < 0,05). Heat stress (34°C) also significantly causing stress to both (pperna < 0,01; pvasticardium < 0,05), though the values of their survivorship was not differ significantly when they were compared (p > 0,05). Based on the result, can be concluded that even both factors are stressors for each species, P. viridis has better tolerance to hypoxia than V. cf. flavum; as in heat stress, both species undergo the same impact in attempt to survive.
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Judul: Pengaruh simulasi transportasi kapal terhadap kerentanan Kerang Hijau Perna viridis pada stress suhu yang meningkat.
Abstrak: The introduced species are species which exceed their natural distribution limits (native range) by a certain mode of introduction (vector). Natural movements are responsible to limited extent. These introduction of a species could influence the susceptibility of a species to environmental stress no matter if introduced purposely or unpurposely. Introduction of species can happen caused by natural movement i.e. organism can movement influenced by current and some organism can migrate to one area to other area; and human activity either purposely i.e. aquarium trade, aquaculture or unpurposely such as accidentally through fouling on ship hulls (Baker et al., 2007). But dominant vector which have large contribution on species introduction is transport by ship hulls and ballast water tanks (Mead et al., 2011). Ballast water tank used to keep the balancing of the ship and some organism has ability to attach on the wall of ship hulls. Introduction species by ships mostly happened where a lot of traffic journey of cargo ship bigger than 10.000 GT during 2007 (Kaluza et al., 2010). Based on data from Global cargo ship network (GCSN), shipping moves over 80 % of the world the goods. The problem is that ships do not only bring the goods but also bring species in the ship hulls and ballast water tank (Kölzsch and Blasius, 2011). The question is what happened to transport condition? For introduction of species, there are a wide variety of transfer mechanisms (vectors) available for hitchhiking of marine invaders to travel and spread in large amount of individuals; but only small amount of individuals can be robust and act as competitors to get food supply in the new environment, it called invasive species. Marine invasive species are defined as non-native species that cause or are likely to cause harm to ecosystems, economies, and or public health (Bax et al., 2003; ISAC, 2006). Based on Lenz et al (2011), they compare native and non-native marine invertebrates regarding their tolerance to stress. Six Bivalve (native named first): Brachidontes exustus and Perna viridis (Trinidad), P. perna and Isognomon bicolor (Brazil), Saccostrea glomerata and Crassostrea gigas (New Zealand); two Ascidians: Diplosoma listerianum and Didemnum vixellum (Wales); and two Crustaceans: Gammarus zaddachi and G. tigrinus (Finland) has been investigated. They found that non native are more resistant towards environmental stress, such as desalination, warming and hypoxia, than taxonomically related and ecologically similar native species. Kleunen et al. (2010) said that tolerance towards abiotic stress is a key trait that determines the invasiveness of species. Furthermore, this was surprise and therefore pronounced differences in tolerant towards stress exist between different species. One possible explanation for this observation are adverse condition during transport, e.g. in the ship hulls and ballast water tanks of cargo vessels. The introduction of species more increased since past century (Mead et al., 2011), and needed mimicking ship transport to know whether that species can vii increase their tolerance during transport. The objective for this experiment is to investigate whether P. viridis can increase their tolerance during transport. The experimental approach have connection with simulated ship transport and be rather
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Judul: Some Construction of 8N-Dimensional Perfect Magic Cube with Arithmetic Sequence
Abstrak: Matematika dikenal dengan sebutan induk dari ilmu-ilmu yang berkembang. Sadar atau tidak sadar, matematika digunakan hampir di setiap aspek kehidupan. Matematika biasanya diperkenalkan di awal jenjang pendidikan sekolah yang merupakan mata pelajaran umum dan merupakan bagian mendasar dari kurikulum sekolah. Sebagian besar siswa menganggap matematika adalah ilmu yang sulit dipahami bahkan ada yang tidak suka dan merasa bosan dengan matematika. Pada sumumnya hal tersebut dirasakan sejak bangku sekolah dasar sehingga pemikiran tersebut memengaruhi alam bawah sadar hingga dewasa kelak. Selama ribuan tahun, teka-teki matematika seperti persegi ajaib (magic square) dan kubus ajaib (magic cube) telah membangkitkan minat anak-anak dan orang dewasa untuk diselesaikan. Permasalahan magic square (MS) adalah bagaimana cara menyusun sejumlah m bilangan asli dalam kotak persegi (matriks) berukuran mx m sedemikian sehingga baris, kolom dan dua diagonal utama berjumlah sama. Magic cube (MC) adalah perluasan dimensi dari magic square yang entrinya berisi bilangan asli dalam matriks kubus berukuran mx mx m sedemikian sehingga baris, kolom, pilar, diagonal ruang berjumlah sama. Kubus ajaib sempurna atau perfect magic cube (PMC) adalah perluasan sifat dari magic cube. Perfect magic cube adalah matriks kubus berukuran mx m × m. yang entrinya bilangan asli yang disusun sedemikian sehingga baris, kolom, pilar, diagonal ruang, dan diagonal bidang berjumlah sama. Sifat magic square, magic cube, dan perfect magic cube dapat diterapkan ke dalam beberapa cabang ilmu lain seperti: kriptografi, steganografi, secret sharing, public key, teori bilangan, matrix field dan coding and error correctness. Semakin banyak jenis pengonstruksian dari MS, MC, dan PMC maka penerapan ke cabang ilmu lain juga semakin beragam. Oleh karena itu, penelitian ini bertujuan untuk mengonstruksi perfect magic cube yang diperumum (berukuran 8 x 8 x 8n) yang entrinya berisi barisan aritmetika dengan angka awal (a) dan beda (B) yang diatur sedemikian sehingga ditemukan pola tertentu dan algoritma pengonstruksian perfect magic cube kemudian diimplementasikan ke dalam bahasa program Python untuk menyelesaikan order yang lebih besar. Penelitian ini diawali dengan membuktikan eksistensi perfect magic cube of onder 8 dan 16 dengan barisan aritmetika kemudian mengonstruksi algoritma perfect magic cube of order 8 dan 16. Setelah didapat, dilakukan rekapitulasi dan melakukan uji kelayakan algoritma hingga order yang besar kemudian dibuat program pengonstruksian perfect magic cube order 8n untuk n≥1 menggunakan software Python serta membuat ilustrasi dengan ketentuan tertentu. Pada tahap akhir dilakukan pembuktikan eksistensi perfect magic cube order 8n untuk n≥ 1. Pengonstruksian perfect magic cube of order 8n didasarkan pada pembentukan pola dan algoritma serta angka awal (a) dan beda (B) dapat disesuaikan untuk BEZ. Pola dan algoritma perfect magic cube of order 8n untuk n = 1 menjadi hesis dalam mengonstruksi perfect magic cube of order 8n untuk n > 1.
Keyword: arithmetic sequence, magic cube, magic square, perfect magic cube