1,877 research outputs found

    The Albedo Distribution of Near Earth Asteroids

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    The cryogenic WISE mission in 2010 was extremely sensitive to asteroids and not biased against detecting dark objects. The albedos of 428 Near Earth Asteroids (NEAs) observed by WISE during its fully cryogenic mission can be fit quite well by a 3 parameter function that is the sum of two Rayleigh distributions. The Rayleigh distribution is zero for negative values, and follows f(x)=xexp[x2/(2σ2)]/σ2f(x) = x \exp[-x^2/(2\sigma^2)]/\sigma^2 for positive x. The peak value is at x=\sigma, so the position and width are tied together. The three parameters are the fraction of the objects in the dark population, the position of the dark peak, and the position of the brighter peak. We find that 25.3% of the NEAs observed by WISE are in a very dark population peaking at pV=0.03p_V = 0.03, while the other 74.7% of the NEAs seen by WISE are in a moderately dark population peaking at pV=0.168p_V = 0.168. A consequence of this bimodal distribution is that the Congressional mandate to find 90% of all NEAs larger than 140 m diameter cannot be satisfied by surveying to H=22 mag, since a 140 m diameter asteroid at the very dark peak has H=23.7 mag, and more than 10% of NEAs are darker than p_V = 0.03.Comment: 7 pages LaTex, 4 figures, accepted for publication in the Astronomical Journa

    Nurses\u27 Alumnae Association Bulletin - Volume 6 Number 10

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    Financial Report Calendar of Events Attention, Class of 1945! Miss Shafer Retires Review of the Alumnae Association Meetings Institutional Staff Nurses\u27 Section Report of Staff Activites - 1948-1949 The Staff Stockings! Stockings! Stockings! Pop-Up Toaster It\u27s Not Too Soon Any White Elephants? Private Duty Section The Jefferson Hospital Private Duty Nurses\u27 Register Report for Barton Memorial Hospital Progress of the Orthopedic Department Just Under the Date Line Pediatrics at Jefferson Controlled Respiration in Anesthesia Anesthesia Progress Physical Advances at Jefferson During the Past Year The White Haven Division The Clara Melville Scholarship Fund The Relief Fund The Busy Year for the Nurses\u27 Home Committee of the Women\u27s Board The Gray Ladies Memories Lost Miscellaneous Items Medical College News Marriages Births Deaths Condolences Prizes District No. 1 Dues Help! Help! Help! Jap Prison School Spurs Nurse to Win University Degree Twenty Ways to Kill an Organization The Bulletin Committee Attention, Alumnae New Addresse

    Descriptive osteology and patterns of limb loss of the European limbless skink Ophiomorus punctatissimus (Squamata, Scincidae)

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    The limbless skink Ophiomorus punctatissimus is a cryptozoic species found in the Peloponnese region of Greece and on the Greek island Kythira. To provide the first thorough description of the cranial and postcranial osteology of this species, both disarticulated specimens and X-ray computed tomographies of wet-preserved specimens were examined in detail. Resulting from this, an anatomical atlas of this species is provided. Two separate considerations, an evolutionary and an ecomorphological one, are made based on the observed adaptations related to limb loss in this skink. The structure of the girdles shows a particular pattern of reduction: whereas the pelvic girdle is mostly vestigial, the pectoral girdle is instead well developed, with all the elements typical of limbed lizards except for the actual limbs. This led us to hypothesize an asynchronous pattern of limb reduction during the evolution of this species, in which the hindlimbs regressed earlier than the forelimbs. Furthermore, considerations based on overall body morphology, osteology and the structure of the inner ear led to the recognition of this species as a burrowing ecomorph. In contrast to the morphology normally displayed in this ecomorph, O. punctatissimus is characterized by the retention of autotomic vertebrae in its tail. This is consistent with the habitats in which it lives, where active burrowing would be difficult because of the hard, rocky terrain. Instead, this skink hides among rocks on the surface and is, therefore, subject to greater predation risk

    Nurses\u27 Alumnae Association Bulletin - Volume 4 Number 7

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    Welcome Home Jefferson Unit Honored by Army Sincere Thanks Treasurer Report Calendar of Events Graduate Nurses\u27 Chorus Lest You Forget Attention Hi-Light of the Alumnae Association Meetings Ambitions for Alumnae Association Notice! Items to Remember Baccalaureate Service Graduating Class Private Duty News Central Dressing Room and Transfusion Unit Card Party Held The Clara Melville Scholarship Fund Staff News Notes on Urologic Nursing Capping Exercises The Poet\u27s Corner Pylephlebitis Student Nurse\u27s View Point The Transfusion Unit Improvements in the Nurses\u27 Home Jefferson Medical College Hospital School of Nursing Faculty Nurses Taking Advanced Courses Nurses in Anesthesia The Student Nurses\u27 Loan Fund A New and Improved Department for Diseases of the Chest Miscellaneous Items Jefferson\u27s Main Kitchen Activities Medical College News Purchasing Procedures Pinky Patter Flash! Class of 1932 Condolences Positions Thirty-Eighth General Hospital Nurses\u27 Reunion Engagements Marriages New Arrivals Deaths The Bulletin Committee Attention Alumnae New Addresse

    FIRE Spectroscopy of Five Late-type T Dwarfs Discovered with the Wide-field Infrared Survey Explorer

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    We present the discovery of five late-type T dwarfs identified with the Wide-field Infrared Survey Explorer (WISE). Low-resolution near-infrared spectroscopy obtained with the Magellan Folded-port InfraRed Echellette (FIRE) reveal strong water and methane absorption in all five sources, and spectral indices and comparison to spectral templates indicate classifications ranging from T5.5 to T8.5:. The spectrum of the latest-type source, WISE J1812+2721, is an excellent match to that of the T8.5 companion brown dwarf Wolf 940B. WISE-based spectrophotometric distance estimates place these T dwarfs at 12-13 pc from the Sun, assuming they are single. Preliminary fits of the spectral data to the atmosphere models of Saumon & Marley indicate effective temperatures ranging from 600 K to 930 K, both cloudy and cloud-free atmospheres, and a broad range of ages and masses. In particular, two sources show evidence of both low surface gravity and cloudy atmospheres, tentatively supporting a trend noted in other young brown dwarfs and exoplanets. In contrast, the high proper motion T dwarf WISE J2018-7423 exhibits a suppressed K-band peak and blue spectrophotometric J-K colors indicative of an old, massive brown dwarf; however, it lacks the broadened Y-band peak seen in metal-poor counterparts. These results illustrate the broad diversity of low-temperature brown dwarfs that will be uncovered with WISE.Comment: 19 pages, 13 figures; accepted for publication to Ap

    Nurses\u27 Alumnae Association Bulletin - Volume 6 Number 9

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    Remember the Relief Fund Welcome! Miss Childs Financial Report Calendar of Coming Events Lest You Forget! Attention Review of the Alumnae Association Meetings Institutional Staff Nurses\u27 Section Report of Staff Activities - 1947-1948 Private Duty Section The White Haven Division Barton Memorial Division Remember the Relief Fund Student Nurses\u27 Activities Jefferson Scores Again The Clara Melville Scholarship Fund Interesting Activities of the Nurses\u27 Home Committee of the Women\u27s Board Exclusive for Nurses Changes in the Maternity Division Gray Lady Musical Therapy Service Memorial Service Honoring Mrs. Bessie Dobson Altemus The Blood Donor Center The Hospital Pharmacy Medical College News Remember the Relief Fund Administrative Staff and Faculty of the School of Nursing Streptomycin Changes in the Staff at Jefferson Hospital Care of the Thoracic Surgical Patient Miscellaneous Items Marriages New Arrivals Deaths The Bulletin Committee Attention, Alumnae New Addresse

    NEOWISE-R Observation of the Coolest Known Brown Dwarf

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    The Wide-field Infrared Survey Explorer (WISE) spacecraft has been reactivated as NEOWISE-R to characterize and search for Near Earth Objects. The brown dwarf WISE J085510.83-071442.5 has now been reobserved by NEOWISE-R, and we confirm the results of Luhman (2014b), who found a very low effective temperature (250\approx 250 K), a very high proper motion (8.1 +/- 0.1 arcsec/yr) , and a large parallax (454 +/- 45 mas). The large proper motion has separated the brown dwarf from the background sources that influenced the 2010 WISE data, allowing a measurement of a very red WISE color of W1-W2 >3.9> 3.9 mag. A re-analysis of the 2010 WISE astrometry using only the W2 band, combined with the new NEOWISE-R 2014 position, gives an improved parallax of 448 +/- 33 mas and proper motion of 8.08 +/- 0.05\; arcsec/yr. These are all consistent with Luhman (2014b).Comment: 6 pages, AJ accepte

    WISE/NEOWISE Preliminary Analysis and Highlights of the 67P/Churyumov-Gerasimenko Near Nucleus Environs

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    On January 18-19 and June 28-29 of 2010, the Wide-field Infrared Survey Explorer (WISE) spacecraft imaged the Rosetta mission target, comet 67P/Churyumov-Gerasimenko. We present a preliminary analysis of the images, which provide a characterization of the dust environment at heliocentric distances similar to those planned for the initial spacecraft encounter, but on the outbound leg of its orbit rather than the inbound. Broad-band photometry yields low levels of CO2 production at a comet heliocentric distance of 3.32 AU and no detectable production at 4.18 AU. We find that at these heliocentric distances, large dust grains with mean grain diameters on the order of a millimeter or greater dominate the coma and evolve to populate the tail. This is further supported by broad-band photometry centered on the nucleus, which yield an estimated differential dust particle size distribution with a power law relation that is considerably shallower than average. We set a 3-sigma upper limit constraint on the albedo of the large-grain dust at <= 0.12. Our best estimate of the nucleus radius (1.82 +/- 0.20 km) and albedo (0.04 +/- 0.01) are in agreement with measurements previously reported in the literature
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