The Flux Ratio Method for Determining the Dust Attenuation of Starburst Galaxies

The presence of dust in starburst galaxies complicates the study of their stellar populations as the dust's effects are similar to those associated with changes in the galaxies' stellar age and metallicity. This degeneracy can be overcome for starburst galaxies if UV/optical/near-infrared observations are combined with far-infrared observations. We present the calibration of the flux ratio method for calculating the dust attenuation at a particular wavelength, Att(\lambda), based on the measurement of F(IR)/F(\lambda) flux ratio. Our calibration is based on spectral energy distributions (SEDs) from the PEGASE stellar evolutionary synthesis model and the effects of dust (absorption and scattering) as calculated from our Monte Carlo radiative transfer model. We tested the attenuations predicted from this method for the Balmer emission lines of a sample starburst galaxies against those calculated using radio observations and found good agreement. The UV attenuation curves for a handful of starburst galaxies were calculated using the flux ratio method, and they compare favorably with past work. The relationship between Att(\lambda) and F(IR)/F(\lambda) is almost completely independent of the assumed dust properties (grain type, distribution, and clumpiness). For the UV, the relationship is also independent of the assumed stellar properties (age, metallicity, etc) accept for the case of very old burst populations. However at longer wavelengths, the relationship is dependent on the assumed stellar properties.Comment: accepted by the ApJ, 18 pages, color figures, b/w version at http://mips.as.arizona.edu/~kgordon/papers/fr_method.htm

Silicon nanoparticles and interstellar extinction

To examine a recently proposed hypothesis that silicon nanoparticles are the source of extended red emission (ERE) in the interstellar medium, we performed a detailed modeling of the mean Galactic extinction in the presence of silicon nanoparticles. For this goal we used the appropriate optical constants of nanosized Si, essentially different from those of bulk Si due to quantum confinement. It was found that a dust mixture of silicon nanoparticles, bare graphite grains, silicate core-organic refractory mantle grains and three-layer silicate-water ice-organic refractory grains works well in explaining the extinction and, in addition, results in the acceptable fractions of UV/visible photons absorbed by silicon nanoparticles: 0.071-0.081. Since these fractions barely agree with the fraction of UV/visible photons needed to excite the observed ERE, we conclude that the intrinsic photon conversion efficiency of the photoluminescence by silicon nanoparticles must be near 100%, if they are the source of the ERE.Comment: Latex2e, uses emulateapj.sty (included), multicol.sty, epsf.sty, 6 pages, 3 figures (8 Postscript files), accepted for publication in ApJ Letters, complete Postscript file is also available at http://physics.technion.ac.il/~zubko/eb.html#SNP

Analisis Finansial dan Strategi Pengembangan USAha Pengolahan Sabut Kelapa Menjadi Serat Kelapa (Coco Fiber) (Studi Kasus : Kecamatan Batang Kuis, Kabupaten Deli Serdang)

Penelitian ini bertujuan untuk untuk menjelaskan bagaimana proses produksi USAha serat kelapa (coco fiber), menganalisis USAha serat kelapa (coco fiber) sudah layak atau tidak, dan menjelaskan strategi pengembangan yang cocok untuk USAha serat kelapa (coco fiber) di daerah penelitian. Daerah penelitian ditentukan secara sengaja (purposive) berdasarkan pertimbangan tertentu, yaitu di Kecamatan Batang Kuis, Kabupaten Deli Serdang. Penarikan sampel dilakukan dengan metode teknik purposive sampling (sengaja) dengan pertimbangan bahwa responden/sampel penelitian adalah pelaku baik individu atau lembaga yang dianggap mengerti permasalahan yang terjadi dan mempunyai kemampuan dalam pembuatan kebijakan, yaitu UD. Pusaka Bakti. Metode analisis yang digunakan adalah Analisis Deskriptif, Analisis Finansial break even point (BEP), imbangan penerimaan dan biaya (revenue-cost ratio), pay-back period (PBP), dan return on investment (ROI) dan Analisis Matriks SWOT. Hasil penelitian menunjukkan USAha serat kelapa (coco fiber) layak untuk diusahakan di daerah penelitian. Hal ini dapat dilihat dari jumlah produksi serat kelapa (coco fiber) yaitu 117.000 kg/tahun berada di atas BEP produksi yaitu 83.147,78kg/tahun dan harga jual serat kelapa (coco fiber) yaitu Rp 2.800/kg juga berada di atas BEP harga yaitu Rp 1.989,86/kg, nilai R/C Ratio > 1 yaitu sebesar 1,40, periode pengembalian modal (PBP) selama 33 bulan, dan ROI sebesar 36,26% lebih besar dari suku bunga dasar kredit bank sebesar 14,60%. Strategi pengembangan USAha serat kelapa (coco fiber) di daerah penelitian berdasarkan analisis matriks SWOT yaitu menekan harga bahan baku untuk memperkecil biaya, memaksimalkan penggunaan bahan baku yang melimpah, melalui proses produksi yang efektif dan efisien untuk menghasilkan produk yang lebih bervariasi, mengusahakan pengembangan dan pelatihan manajemen sehingga lebih teratur dan pekerjanya memiliki etos kerja tinggi, memodifikasi produk agar dapat bersaing dengan produk lain dan pendatang baru, membuat business plan mulai dari lokasi, permodalan, variasi produk (produksi) hingga pemasaran untuk menarik minat konsumen, memperbaiki manejemen waktu dan kerja, rotasi kegiatan, dan penyimpanan

Antibacterial Activity of Papaya Leaf Extracts Against Pathogenic Bacteria

It was reported that the extracts of papaya leaves could inhibit the growth of Rhizopus stolonifer. Antibacterial activity of Carica papaya leaf extracts on pathogenic bacteria was observed in this study. Papaya leaves were extracted by using maceration method and three kinds of solvents: ethanol, ethyl acetate, and hexane. Papaya leaf extracts were tested against Bacillus stearothermophilus, Listeria monocytogenes, Pseudomonas sp., and Escherichia coli by agar diffusion method. The objectives of this study were to determine extract ability against pathogenic bacteria, to observe the influence of pH, NaCl, and heat on extracts ability, and to observe extract ability against B. stearothermophilus spores. The data showed that ethyl acetate extract could inhibit B. stearothermophilus, L. monocytogenes, Pseudomonas sp., and E. coli. The extract activity was influenced by pH, and it was more effective in low pH. The extract activity was influenced by NaCl against B. stearothermophillus and E. coli. However, it was not influenced by NaCl in bioassay against L. monocytogenes and Pseudomonas sp. The extract activity was influenced by heating process against all the bacteria tested. The extracts inhibited B. stearothermophilus spores as well. Papaya leaves are potential natural anti-bacteria, which might be used in certain kinds of food

Human Exploration of Mars: Preliminary Lists of Crew Tasks

This is a preliminary report of ongoing research that has identified 1,125 tasks that are likely to be performed during initial human expeditions to Mars. The purpose of the report is to facilitate immediate access to the task inventory by researchers whose efforts might benefit from concrete examples of the work that will likely be performed by the first human explorers of Mars and the tasks for which crew members must be prepared to perform in response to emergencies. The research that led to the task lists is being conducted under Cooperative Agreement NNX15AW34G / NNX16AQ86G for the Human Factors and Behavioral Performance Element, Human Performance Program, NASAs Johnson Space Center. The study is ongoing and will conclude with a final report that documents all research activities and presents the results of task and ability analyses and the implications of study results to crew size and composition, personnel selection and training, and design of equipment and procedures. The research addresses the Risk of Inadequate Mission, Process, and Task Design and the Risk of Performance Errors Due to Training Deficiencies by identifying the work that will be performed during an expedition to Mars and the abilities, skills, and knowledge that will be required of crew members. The study began by developing the comprehensive inventory of 1,125 tasks that are likely to be performed during the 12 phases of initial human expeditions to Mars, from launch to landing 30 months later. This full-mission task inventory was generated by a comprehensive review of documentation and concepts of operations with the understanding that plans and tasks might change in response to continuing technological development. Note: This interim report includes no discussion of analyses and has been prepared solely to facilitate dissemination of the task lists to others whose research might benefit from detailed information about the work and other activities that are likely to be performed during the human exploration of Mars

Kajian Normatif: Pengelolaan Perbataan dan Kelembagaan Pusat-daerah Berdasarkan Rencana Induk Pengelolaan Perbatasan Negara

Penulis ingin menelaah bagaimana rentang kendali kelembagaan dari pusat ke daerah dalam mengelolawilayah perbatasan berdasarkan rencana induk pengelolaan perbatasan negara. Rencana induk pengelolaanbatas wilayah negara dan kawasan perbatasan atau Rinduk adalah rencana pembangunan nasional jangkamenengah 5 (lima) tahun yang memberikan arah kebijakan, strategi, dan program pengelolaan batas wilayahnegara dan pembangunan kawasan perbatasan yang berpedoman pada Rencana Pembangunan Jangka PanjangNasional atau RPJPN dan Rencana Pembangunan Jangka Menengah Nasional atau RPJMN. Metode penelitianpada paper ini menggunakan metode normatif, dimana secara kualitatif ditelaah berbagai regulasi yang terkaitdengan lembaga dan kelembagaan pengelola perbatasan Negara Kesatuan Republik Indonesia. Regulasimengenai kelembagaan (Badan Nasional Pengelola Perbatasan (BNPP) yang mengatur tata kelola wilayahperbatasan negara sudah ada, namun perlu penguatan kelembagaan yang lebih lagi, pelatihan sumber dayamanusia dan penyediaan dana yang dibutuhkan sesuai dengan prioritas penanganan perbatasan Negara

KNO 3 Application Affect Growth and Production of Amorphophallus Muelleri Blume

Pemberian larutan KNO3 diduga dapat meningkatkan produktivitas tanaman iles-iles (Amorphophallus muelleriBlume). Penelitian bertujuan mempelajari pengaruh pemberian larutan KNO terhadap produktivitas A. muelleri. Umbiutuh umur satu tahun dengan bobot 100-125 g ditanam dalam polibag yang ditempatkan di bawah naungan paranet 50%pada musim hujan (September 2010-April 2011) di Bogor, Indonesia. Lima taraf larutan KNO3 yaitu 0, 2, 4, 6 dan 8% (b/v)diberikan melalui daun dan melalui tanah. Larutan diberikan 2 kali sebulan mulai 12 minggu setelah tanam (MST). Hasilmenunjukkan bahwa pemberian KNO3-13 nyata mempengaruhi pertumbuhan tanaman, khususnya meningkatkan jumlah daundan memperpanjang masa vegetatif. Pemberian KNO pada taraf 4% memberikan pengaruh tertinggi jika diberikan melaluidaun. Pemberian KNO33 taraf 4% memberikan pertumbuhan yang lebih tinggi jika diberikan melalui daun dibandingkanmelalui tanah. Secara umum, tidak ada pengaruh nyata pada pertumbuhan tanaman akibat pemberian dosis KNO yangdiberikan melalui tanah. Penelitian berimplikasi bahwa pemberian pupuk KNO melalui daun pada taraf 4% dapatditingkatkan efektivitasnya jika kerusakan pada anak daun dapat diminimalkan. Kerusakan daun cenderung meningkat padadaun tua, oleh karena itu, studi lanjut perlu dilakukan terkait waktu aplikasi yang tepat

The Ammount of Interstellar Carbon Locked in Solid Hydrogenated Amorphous Carbon

We review the literature and present new experimental data to determine the amount of carbon likely to be locked in form of solid hydrogenated amorphous carbon (HAC) grains. We conclude on the basis of a thorough analysis of the intrinsic strength of the C-H stretching band at 3.4 micron that between 10 and 80 ppM H of carbon is in the form of HAC grains. We show that it is necessary to know the level of hydrogenation (H/C) of the interstellar HAC to determine more precisely the amount of carbon it ties up. We present optical constants, photoluminescence spectroscopy, and IR absorption spectroscopy for a particular HAC sample that is shown to have a 3.4 micron absorption feature that is quantatively consistent with that observed in the diffuse interstellar medium.Comment: This paper is 14 pages long with 5 figures and will appear in the 1 December 1999 issue of Ap