674 research outputs found

    Deep MERLIN 5GHz Radio Imaging of Supernova Remnants in the M82 Starburst

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    The results of an extremely deep, 8-day long observation of the central kpc of the nearby starburst galaxy M82 using MERLIN (Multi-Element Radio Linked Interferometer Network) at 5 GHz are presented. The 17E-06 Jy/beam, rms noise level in the naturally weighted image make it the most sensitive high resolution radio image of M82 made to date. Over 50 discrete sources are detected, the majority of which are supernova remnants, but with 13 identified as HII regions. Sizes, flux densities and radio brightnesses are given for all of the detected sources, which are all well resolved with a majority showing shell or partial shell structures. Those sources within the sample which are supernova remnants have diameters ranging from 0.3 to 6.7 pc, with a mean size of 2.9 pc. From a comparison with previous MERLIN 5 GHz observations made in July 1992, which gives a 9.75 year timeline, it has been possible to measure the expansion velocities of ten of the more compact sources, eight of which have not been measured before. These derived expansion velocities range between 2200 and 10500 km/s.Comment: 34 pages, 10 figures. Accepted by MNRA

    15 years of VLBI observations of two compact radio sources in Messier 82

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    We present the results of a second epoch of 18cm global Very Long-Baseline Interferometry (VLBI) observations, taken on 23 February 2001, of the central kiloparsec of the nearby starburst galaxy Messier 82. These observations further investigate the structural and flux evolution of the most compact radio sources in the central region of M82. The two most compact radio objects in M82 have been investigated (41.95+575 and 43.31+592). Using this recent epoch of data in comparison with our previous global VLBI observations and two earlier epochs of European VLBI Network observations we measure expansion velocities in the range of 1500-2000km/s for 41.95+575, and 9000-11000km/s for 43.31+592 using various independent methods. In each case the measured remnant expansion velocities are significantly larger than the canonical expansion velocity (500km/s) of supernova remnants within M82 predicted from theoretical models. In this paper we discuss the implications of these measured expansion velocities with respect to the high density environment that the SNR are expected to reside in within the centre of the M82 starburst.Comment: Accepted for publication in MNRAS, 9 pages, 8 figure

    Social, environmental and psychological factors associated with objective physical activity levels in the over 65s

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    Objective: To assess physical activity levels objectively using accelerometers in community dwelling over 65 s and to examine associations with health, social, environmental and psychological factors. Design: Cross sectional survey. Setting: 17 general practices in Scotland, United Kingdom. Participants: Random sampling of over 65 s registered with the practices in four strata young-old (65–80 years), old-old (over 80 years), more affluent and less affluent groups. Main Outcome Measures: Accelerometry counts of activity per day. Associations between activity and Theory of Planned Behaviour variables, the physical environment, health, wellbeing and demographic variables were examined with multiple regression analysis and multilevel modelling. Results: 547 older people (mean (SD) age 79(8) years, 54% female) were analysed representing 94% of those surveyed. Accelerometry counts were highest in the affluent younger group, followed by the deprived younger group, with lowest levels in the deprived over 80 s group. Multiple regression analysis showed that lower age, higher perceived behavioural control, the physical function subscale of SF-36, and having someone nearby to turn to were all independently associated with higher physical activity levels (R2 = 0.32). In addition, hours of sunshine were independently significantly associated with greater physical activity in a multilevel model. Conclusions: Other than age and hours of sunlight, the variables identified are modifiable, and provide a strong basis for the future development of novel multidimensional interventions aimed at increasing activity participation in later life.Peer reviewe

    Desain Unit Pengolahan Bioetanol Untuk Petani Di Desa Ngajum Kecamatan Sumber Pucung Kabupaten Malang

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    The aim of the research is to develop bio-ethanol processing unit in small size using simple technology, which can be used by Cassava farmers in the village of Ngajum Sumber Pucung Malang. The capacity of Bioethanol processing unit provided is 100 liters/process which consists of sieve, cooker with cooling mash, fermenter, and distillation unit. Tests on several processing units give the following results: Sieve driven by 7.5 HP diesel engines. Sieve cylinder made of wood cylinder with 40 cm of diameter and 45 cm of length. Sieve has a capacity of 613 kg/h. Cooker tank made of stainless steel plate 4 mm and has dimensions 77 cm of diameter and 150 cm of height. There are 4 pieces of pipe stainless steel 6" placed at the bottom serving as heat exchanger. Cooling Mash has heat transfer surface area of 3.11 m2 that consists of 26 stainless steel pipe 1 ½" of diameter and 100 cm of length . Cooking efficiency is 38% with fuel of firewood with a moisture content of 50%. At steady state conditions, Cooling mash is capable to remove energy from substance of 280 kcal/min at mass flow rate of substance of 2.34 l/s and mass flow rate of cooling water of 0.6 l/s.Fermenter tank has made of stainless steel and has dimensions 110 cm of diameter and 240 cm of height. The mixer's fermenter is driven by a ½ HP electric motor. To maintain the material temperature at 32 oC, the fermenter equipped with a cooling unit that is sprinkler water around the tube. Distillation unit has made of stainless steel 304 and consists of beer column, the column rectifying, pre-heater, condensers and equipped with boiler

    Perancangan Visualisasi Keris 3d dengan Layanan Augmented Reality Cloud-recognition

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    Salah satu obyek budaya tradisional yang populer adalah keris. Senjata tradisional ini memiliki bentuk yang indah. Pengetahuan masyarakat mengenai keris semakin berkurang, hal ini karena media yang digunakan untuk memperkenalkan keris yang kurang menarik dan sulit diperoleh. Oleh karena itu dibutuhkan suatu media baru untuk memperkenalkan keris kepada masyarakat luas. Pengguna dapat dengan mudah memindai ponsel mereka pada media yang disediakan dan memperoleh data tentang keris. Obyek keris akan dibuat virtual sehingga dapat dikenal dengan cukup menarik oleh masyarakat. Obyek keris akan dimodelkan secara 3 dimensi, lalu digabungkan dengan pola penanda. Dengan menggunakan teknologi Augmented Reality maka diharapkan dapat menggabungkan obyek keris secara virtual dengan pola penanda pada media promosi. Pembuatan Augmented Reality obyek keris ini memanfaatkan fitur-fitur dari layanan Vuforia, AutoCad123D, dan Unity Game Designer. Vuforia menyediakan fitur pengenalan pola Augmented Reality secara remote. Autocad123D menyediakan layanan pemodelan 3D dengan baik. Unity game designer menyediakan layanan untuk menggabungkan kedua layanan Vuforia dan Autocad123D. Dengan menggunakan layanan tersebut maka akan didapatkan aplikasi yang cukup ringan, mengurangi beban komputasi pada client, menjadi lebih ramah memori, dan kemudahan dalam memperbarui aplikasi di pihak client

    New Constraints from PAMELA anti-proton data on Annihilating and Decaying Dark Matter

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    Recently the PAMELA experiment has released its updated anti-proton flux and anti-proton to proton flux ratio data up to energies of ~200GeV. With no clear excess of cosmic ray anti-protons at high energies, one can extend constraints on the production of anti-protons from dark matter. In this letter, we consider both the cases of dark matter annihilating and decaying into standard model particles that produce significant numbers of anti-protons. We provide two sets of constraints on the annihilation cross-sections/decay lifetimes. In the one set of constraints we ignore any source of anti-protons other than dark matter, which give the highest allowed cross-sections/inverse lifetimes. In the other set we include also anti-protons produced in collisions of cosmic rays with interstellar medium nuclei, getting tighter but more realistic constraints on the annihilation cross-sections/decay lifetimes.Comment: 7 pages, 3 figures, 3 table

    High-velocity-resolution observations of OH main line lasers in the M82 starburst

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    Using the VLA, a series of high velocity resolution observations have been made of the M82 starburst at 1.6 GHz. These observations follow up on previous studies of the main line OH maser emission in the central kiloparsec of this starburst region, but with far greater velocity resolution, showing significant velocity structure in some of the maser spots for the first time. A total of thirteen masers were detected, including all but one of the previously known sources. While some of these masers are still unresolved in velocity, these new results clearly show velocity structure in spectra from several of the maser regions. Position-velocity plots show good agreement with the distribution of H{\sc i} including interesting velocity structure on the blueward feature in the west of the starburst which traces the velocity distribution seen in the ionised gas.Comment: MNRAS in press. 15 pages, 9 figure
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