129 research outputs found

    Perkembangan Morfologi Dan Perilaku Larva Ikan Kerapu Hibrida Cantik Pada Produksi Massal

    Get PDF
    Ikan kerapu cantik merupakan hibrida antara betina kerapu macan E. fuscoguttatus dan jantan kerapu batik E. microdon. Penelitian ini bertujuan untuk mengamati perkembangan dan tingkah laku larva ikan kerapu cantik agar bisa diambil langkah-langkah untuk perbaikan pada pemeliharaan larva sehingga dapat meningkatkan produksi. Penelitian dilakukan di Balai Besar Riset Budidaya Laut dan Penyuluhan Perikanan Gondol, Bali Tahun 2016. Larva dipelihara pada tiga buah bak semen ukuran 10 m3 yang diisi telur dengan kepadatan 50.000 butir/bak, dipelihara hingga juvenil umur 40 hari (D40). Pemeliharaan larva diulang tiga kali dengan waktu yang berbeda, yaitu siklus 1: Januari-Maret; siklus 2 : Mei-Juli dan siklus 3 : September-Nopember. Pengamatan perkembangan dan tingkah laku larva dilakukan pada setiap siklus yang dibagi menjadi 4 kelompok umur, yakni: 1) D1 sampai D10; 2). D11 sampai D20; 3). D21 sampai D30; dan 4). D31 sampai D40. Hasil menunjukkan larva ikan kerapu cantik mulai buka mulut dan makan pada D3, aktif berenang setelah tumbuh sirip punggung dan dada yaitu D4, sirip terus berkembang menjadi duri memanjang. D7 kondisi larva terlihat padat dilakukan penjarangan. Duri punggung dan dada mulai memendek, berubah menjadi sirip mulai D30, selanjutnya menjadi juvenil dilakukan grading untuk menekan kanibalisme, D40 dengan ukuran panjang total sekitar 3 cm larva ikan kerapu cantik seluruhnya menjadi juvenil. Perkembangan dan tingkah laku larva ikan kerapu cantik berpengaruh terhadap hasil produksinya

    Electrohydrodynamic-jet (EHD)-printed diketopyrrolopyroole-based copolymer for ofets and circuit applications

    Get PDF
    We report the employment of an electrohydrodynamic-jet (EHD)-printed diketopyrrolopyrrole-based copolymer (P-29-DPPDTSE) as the active layer of fabricated organic field-effect transistors (OFETs) and circuits. The device produced at optimal conditions showed a field-effect mobility value of 0.45 cm2/(Vs). The morphologies of the printed P-29-DPPDTSE samples were determined by performing optical microscopy, X-ray diffraction, and atomic force microscopy experiments. In addition, numerical circuit simulations of the optimal printed P-29-DPPDTSE OFETs were done in order to observe how well they would perform in a high-voltage logic circuit application. The optimal printed P-29-DPPDTSE OFET showed a 0.5 kHz inverter frequency and 1.2 kHz ring oscillator frequency at a 40 V supply condition, indicating the feasibility of its use in a logic circuit application at high voltage

    Ferromagnetic/superconducting proximity effect in La0.7Ca0.3MnO3 / YBa2Cu3O7 superlattices

    Get PDF
    We study the interplay between magnetism and superconductivity in high quality YBa2Cu3O7 (YBCO) / La0.7Ca0.3MnO3(LCMO)superlattices. We find evidence for the YBCO superconductivity depression in presence of the LCMO layers. We show that due to its short coherence length superconductivity survives in the YBCO down to much smaller thickness in presence of the magnetic layer than in low Tc superconductors. We also find that for a fixed thickness of the superconducting layer, superconductivity is depressed over a thickness interval of the magnetic layer in the 100 nm range. This is a much longer length scale than that predicted by the theory of ferromagnetic/superconducting proximity effect.Comment: 10 pages + 5 figures, submitted to Phys. Rev.

    Sequential and direct two-photon double ionization of D2 at FLASH

    Get PDF
    ABSTRACT: Sequential and direct two-photon double ionization (DI) of D2 molecule is studied experimentally and theoretically at a photon energy of 38.8 eV. Experimental and theoretical kinetic energy releases of D++D+ fragments, consisting of the contributions of sequential DI via the D2+(1ssg) state and direct DI via a virtual state, agree well with each other

    Sequential versus nonsequential two-photon double ionization of the D2 molecule at 38 eV

    Get PDF
    ABSTRACT: A simple theoretical model is used to interpret recent experimental results for two-photon double ionization (DI) of D2 at 38 eV. We show that the measured kinetic energy distribution associated with emission of two protons can be interpreted as a sum of two processes: a sequential and an instantaneous absorption of the two incident photons. These processes lead to peaks in di erent regions of the spaectrum

    The preparation of HEMA-MPC films for ocular drug delivery

    Get PDF
    There is a need to prolong drug residence time using a biocompatible formulation in the subconjunctival space after surgery to treat glaucoma. Drug releasing discs were prepared with 2-(hydroxyethyl)methacrylate (HEMA) and 2-methacryloyl-oxyethyl phosphorylcholine (MPC). The ratio of bound water (Wb) to free water (Wf) ratio increased from 1:0.3 to 1:6.8 with increasing MPC (0 to 50%, w/w). The optimal balance between water content, SR and mechanical strength were obtained with 10% MPC (w/w) hydrogels. Water-alcohol mixtures were examined to facilitate loading of poorly soluble drugs, and they showed greater hydrogel swelling than either water or alcohol alone. The SR was 1.2 ± 0.02 and 3.3 ± 0.1 for water and water:ethanol (1:1) respectively. HEMA-MPC (10%) discs were loaded with dexamethasone using either water:ethanol (1:1) or methanol alone. Drug release was examined in an outflow rig model that mimics the subconjunctival space in the eye. Dexamethasone loading increased from 0.3 to 1.9 mg/disc when the solvent was changed from water:ethanol (1:1) to methanol with the dexamethasone half-life (t½) increasing from 1.9 to 9.7 days respectively. These encouraging results indicate that HEMA-MPC hydrogels have the potential to sustain the residence time of a drug in the subconjunctival space of the eye

    Trans−cis Switching Mechanisms in Proline Analogues and Their Relevance for the Gating of the 5-HT3 Receptor

    Get PDF
    Trans-cis isomerization of a proline peptide bond is a potential mechanism to open the channel of the 5-HT3 receptor. Here, we have used the metadynamics method to theoretically explore such a mechanism. We have determined the free energy surfaces in aqueous solution of a series of dipeptides of proline analogues and evaluated the free energy difference between the cis and trans isomers. These theoretical results were then compared with data from mutagenesis experiments, in which the response of the 5-HT3 receptor was measured when the proline at the apex of the M2-M3 transmembrane domain loop was mutated. The strong correlation between the experimental and the theoretical data supports the existence of a trans-cis proline switch for opening the 5-HT3 receptor ion channel

    Transmembrane signalling in eukaryotes: a comparison between higher and lower eukaryotes

    Full text link

    The number of tree species on Earth

    Get PDF
    One of the most fundamental questions in ecology is how many species inhabit the Earth. However, due to massive logistical and financial challenges and taxonomic difficulties connected to the species concept definition, the global numbers of species, including those of important and well-studied life forms such as trees, still remain largely unknown. Here, based on global groundsourced data, we estimate the total tree species richness at global, continental, and biome levels. Our results indicate that there are 73,000 tree species globally, among which ∼9,000 tree species are yet to be discovered. Roughly 40% of undiscovered tree species are in South America. Moreover, almost one-third of all tree species to be discovered may be rare, with very low populations and limited spatial distribution (likely in remote tropical lowlands and mountains). These findings highlight the vulnerability of global forest biodiversity to anthropogenic changes in land use and climate, which disproportionately threaten rare species and thus, global tree richness
    • …
    corecore