XMM-Newton and Gemini Observations of Eight RASSCALS Galaxy Groups

We study the distribution of gas pressure and entropy in eight groups of galaxies belonging to the ROSAT All-Sky Survey / Center for Astrophysics Loose Systems (RASSCALS). We use archival and proprietary XMM-Newton observations, supplementing the X-ray data with redshifts derived from the literature; we also list 127 new redshifts measured with the Gemini North telescope. The groups show remarkable self-similarity in their azimuthally averaged entropy and temperature profiles. The entropy increases with radius; the behavior of the entropy profiles is consistent with an increasing broken power law with inner and outer slope 0.92+0.04-0.05 and 0.42+0.05-0.04 (68% confidence), respectively. There is no evidence of a central, isentropic core, and the entropy distribution in most of the groups is flatter at large radii than in the inner region, challenging earlier reports as well as theoretical models predicting large isentropic cores or asymptotic slopes of 1.1 at large radii. The pressure profiles are consistent with a self-similar decreasing broken power law in radius; the inner and outer slopes are -0.78+0.04-0.03 and -1.7+0.1-0.3, respectively. The results suggest that the larger scatter in the entropy distribution reflects the varied gasdynamical histories of the groups; the regularity and self-similarity of the pressure profiles is a sign of a similarity in the underlying dark matter distributions.Comment: Accepted for publication in the Astrophysical Journa

Flight test results for a separate surface stability augmented Beech model 99

A flight evaluation of a Beech model 99 equipped with an attitude command control system incorporating separate surface stability augmentation (SSSA) was conducted to determine whether an attitude command control system could be implemented using separate surface controls, and to determine whether the handling and ride qualities of the aircraft were improved by the SSSA attitude command system. The results of the program revealed that SSSA is a viable approach to implementing attitude command and also that SSSA has the capability of performing less demanding augmentation tasks such as yaw damping, wing leveling, and pitch damping. The program also revealed that attitude command did improve the pilot rating and ride qualities of the airplane while flying an IFR mission in turbulence. Some disadvantages of the system included the necessity of holding aileron force in a banked turn and excessive stiffness in the pitch axis

Identification of the X-ray pulsar in Hercules: A new optical pulsar

A series of photographic, photoelectric, and spectroscopic observations beginning June 1, 1972 has led to the optical identification of Her X-1 (2U 1705 + 34), a pulsed X-ray source in an eclipsing binary system, with the thirteenth magnitude blue variable star HZ Herculis. The detection of optical pulses at the frequency of the X-ray pulsar on three nights makes the identification conclusive and establishes HZ Her as the second known optical pulsar. The strength of the optical pulses may be correlated with the orbital phase but is not obviously related to the high or low intensity states of the X-ray source

Effects of harvesting methods on sustainability of a bay scallop fishery: dredging uproots seagrass and displaces recruits

Fishing is widely recognized to have profound effects on estuarine and marine ecosystems (Hammer and Jansson, 1993; Dayton et al., 1995). Intense commercial and recreational harvest of valuable species can result in population collapses of target and nontarget species (Botsford et al., 1997; Pauly et al., 1998; Collie et al. 2000; Jackson et al., 2001). Fishing gear, such as trawls and dredges, that are dragged over the seafloor inflict damage to the benthic habitat (Dayton et al., 1995; Engel and Kvitek, 1995; Jennings and Kaiser, 1998; Watling and Norse, 1998). As the growing human population, over-capitalization, and increasing government subsidies of fishing place increasing pressures on marine resources (Myers, 1997), a clear understanding of the mechanisms by which fishing affects coastal systems is required to craft sustainable fisheries management

Investigation to determine the effects of long-term bed rest on G-tolerance and on psychomotor performance Final report

Prolonged bed rest effects on gravity tolerance and psychomotor performance of human

Pengaruh Warna Lampu Dalam Air Terhadap Hasil Tangkapan Bagan Perahu Di Perairan Bacan Kabupaten Halmahera Selatan

Penelitian mengenai penggunaan lampu dalam air pada bagan perahu dilakukan di perairan Bacan dengan tujuan melihat bagaimana pengaruh warna lampu laguna dalam air terhadap hasil tangkapan pada setiap fase umur bulan, serta mengetahui jenis ikan yang tertangkap, dengan menggunakan metode eksperimental di mana data dianalisis dengan menggunakan Rancangan Acak Kelompok (RAK) dan dilanjutkan dengan uji Beda Nyata Terkecil (BNT). Ikan teri (Stolephorus commersonii) merupakan hasil tangkapan yang paling dominan pada setiap fase umur bulan dan pada setiap perbedaan penggunaan warna lampu laguna berwarna dalam air pada ketiga bagan perahu. Penggunaan lampu dalam air berwarna hijau-biru (HB) memberikan hasil tangkapan yang lebih dominan dibandingkan lampu berwarna hijau-hijau (HH) dan biru-biru (BB) pada setiap fase umur bulan. Di samping itu, penggunaan perlakuan perbedaan warna lampu dalam air menunjukkan perbedaan yang nyata secara statistik terhadap jumlah tangkapan ikan teri (Stolephorus commersonii). Hasil tangkapan bagan perahu dengan menggunakan lampu berwarna HB berbeda sangat nyata dengan lampu berwarna BB dan antara lampu berwarna HB dan HH tidak menunjukkan perbedaan yang nyata secara statistik terhadap jumlah hasil tangkapan ikan teri. Terlihat juga bahwa hasil tangkapan ikan teri pada bagan perahu pada saat lampu dioperasikan pada periode umur bulan 1-7 hari berbeda sangat nyata dengan hasil tangkapan pada tiga periode umur bulan lainnya. Dengan demikian, direkomendasikan kepada nelayan perikanan bagan perahu agar menggunakan lampu laguna dalam air dengan kombinasi warna hijau dan biru dan pada saat periode umur bulan di langit 1- 7 hari, karena pada dua kondisi ini akan diperoleh hasil tangkapan ikan teri yang lebih memadai dibandingkan lainnya. Dengan demikian, direkomendasikan kepada nelayan perikanan bagan perahu agar menggunakan lampu laguna dalam air dengan kombinasi warna hijau dan biru dan pada saat periode umur bulan di langit 1- 7 hari, karena pada dua kondisi ini akan diperoleh hasil tangkapan ikan teri yang lebih memadai dibandingkan lainnya