2,837 research outputs found
Strong Aperiodic X-ray Variability and Quasi-Periodic Oscillation in X-ray Nova XTE J1550-564
We report the discovery of strong aperiodic X-ray variability and
quasi-periodic oscillation (QPO) in the X-ray light curves of a new X-ray Nova,
XTE J1550-564, and the evolution of the observed temporal properties during the
rise of the recent X-ray outburst. The power spectral analysis of the first
observation reveals strong aperiodic X-ray variability of the source (~28%), as
well as the presence of a QPO at ~82 mHz with fractional rms amplitude ~14%
over the 2-60 keV energy range. Also apparent is the first harmonic of the QPO
with the amplitude ~9%. As the X-ray flux increases, the source tends to become
less variable, and the QPO frequency increases rapidly, from 82 mHz to 4 Hz,
over the flux (2-50 keV) range of 1.73-5.75 x 10^{-8} ergs cm^{-2} s^{-1}. The
amplitude of the fundamental component of the QPO varies little, while that of
the harmonic follows a decreasing trend. The fundamental component strengthens
toward high energies, while its harmonic weakens. Initially, the power spectrum
is roughly flat at low frequencies and turns into a power law at high
frequencies, with the QPO harmonic sitting roughly at the break. In later
observations, however, the high-frequency portion of the continuum can actually
be better described by a broken power law (as opposed to a simple power law).
This effect becomes more apparent at higher energies. The overall amplitude of
the continuum shows a similar energy dependence to that of the fundamental
component of the QPO. Strong rapid X-ray variability, as well as hard energy
spectrum, makes XTE J1550-564 a good black hole candidate. We compare its
temporal properties with those of other black hole candidates.Comment: 12 pages, including 5 figures. To appear in ApJ Letters, vol. 512
(1999
Ignorance of International Law Is No Excuse, or How the Florida Legislature Ticked Off Canada
During its 2012 session the Florida Legislature amended the text of Florida Statute 322.04 to add a requirement for nonresidents. International visitors would be required to have in their possession not only a valid drivers\u27 license, but also an International Driving Permit (IDP) that translated into English the personal identification information of the driver. The change took effect January 1, 2013, but even before that date, Florida faced allegations that it was violating international law with this new requirement
Ignorance of International Law Is No Excuse, or How the Florida Legislature Ticked Off Canada
During its 2012 session the Florida Legislature amended the text of Florida Statute 322.04 to add a requirement for nonresidents. International visitors would be required to have in their possession not only a valid drivers\u27 license, but also an International Driving Permit (IDP) that translated into English the personal identification information of the driver. The change took effect January 1, 2013, but even before that date, Florida faced allegations that it was violating international law with this new requirement
Bone Turnover Response to Acute Exercise with Varying Impact Levels: A preliminary investigation
International Journal of Exercise Science 8(2): 154-163, 2015. The purpose of this investigation was to determine if there are changes in metabolic markers of bone turnover within the 24-hour period following an acute bout of jogging or water exercise. Ten healthy females (22-30 yr.) underwent three trials with different ground impact forces: jogging, water aerobics and control. For the jogging and water aerobics trials, subjects exercised for 30 min at 60-70% of predicted maximal heart rate in addition to a 5 min warm up and cool down. For the control trial, subjects rested for 40 min, i.e., the total exercise time of the other trials. For each trial, blood samples were collected pre, immediately post, 1 hr. post, and 24 hr. post exercise. All samples were analyzed for levels of osteocalcin, bone specific alkaline phosphatase and cross-linked N telopeptides. A repeated-measure ANOVA was used to determine if there were differences between impact levels or over time. There were no significant differences over time, or between impact levels of exercise. Therefore these results indicate that healthy young women demonstrate no changes in bone turnover within 24 hr. of a single bout of exercise. Due to biochemical markers of bone turnover responding in a similar manner regardless of activity type, these findings suggest that water aerobics can be seen as a beneficial form of exercise for maintenance of bone density
Implementing a Reconciliation and Balancing Model in the U.s. Industry Accounts
As part of the U.S. Bureau of Economic Analysis’ integration initiative (Yuskavage, 2000; Moyer et al., 2004a, 2004b; Lawson et al., 2006), the Industry Accounts Directorate is drawing upon the Stone method (Stone et al., 1942) and Chen (2006) to reconcile the gross operating surplus component of value-added from the 2002 expenditure-based benchmark input-output accounts and the 2002 income-based gross domestic product-by-industry accounts. The objective of the reconciliation is to use information regarding the relative reliabilities of underlying data in both the benchmark input-output use table and the gross domestic product-by-industry accounts in a balanced input-output framework in order to improve intermediate input estimates and gross operating surplus estimates in both accounts. Given a balanced input-output framework, the Stone method also provides a tool for balancing the benchmark use table. This paper presents work by the Industry Accounts Directorate to develop and implement the reconciliation and balancing model. The paper provides overviews of the benchmark use table and gross domestic product-by-industry accounts, including features of external source data and adjustment methodologies that are relevant for the reconciliation. In addition, the paper presents the empirical model that the Industry Accounts Directorate is building and briefly describes the technology used to solve the model. Preliminary work during development of the model shows that reconciling and balancing a large system with disaggregated data is computationally feasible and efficient in pursuit of an economically accurate and reliable benchmark use table and gross domestic product-by-industry accounts.
Radiopyrolysis
Statement of responsibility on title-page reads: E.A. Mason, T.H. Timmins, D.T. Morgan, and W.N. Bley"Issued: October 1966.""MIT-334-70 Reactor Technology."Also issued by T.H. Timmins and supervised by E.A. Mason as an Sc. D. thesis , Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1967Includes bibliographical references (pages A6.1-A6.7)MIT DSR Project no. 79819Work performed for the Savannah River Operations Office, U.S. Atomic Energy Commission under Contract no. AT(38-1)-33
A Network Neuroscience Approach to Typical and Atypical Brain Development.
Human brain networks based on neuroimaging data have already proven useful in characterizing both normal and abnormal brain structure and function. However, many brain disorders are neurodevelopmental in origin, highlighting the need to go beyond characterizing brain organization in terms of static networks. Here, we review the fast-growing literature shedding light on developmental changes in network phenotypes. We begin with an overview of recent large-scale efforts to map healthy brain development, and we describe the key role played by longitudinal data including repeated measurements over a long period of follow-up. We also discuss the subtle ways in which healthy brain network development can inform our understanding of disorders, including work bridging the gap between macroscopic neuroimaging results and the microscopic level. Finally, we turn to studies of three specific neurodevelopmental disorders that first manifest primarily in childhood and adolescence/early adulthood, namely psychotic disorders, attention-deficit/hyperactivity disorder, and autism spectrum disorder. In each case we discuss recent progress in understanding the atypical features of brain network development associated with the disorder, and we conclude the review with some suggestions for future directions
The irradiation of Santowax OMP in the M.I.T. in-pile loop
"May 1962."Issued both as a 2 volume set, or a 2 volumes in 1 set in which p. [169] is the title-page to MITNE-22IDO 11, 104; 11, 105Includes bibliographical referencesM.I.T. DSR project no. 8710U.S. Atomic Energy Commission, Idaho Operations Office contract AT(10-1)-1067pt. 1. Summary to October 5, 1961 -- pt. 2. Equipment design, procedures and results of irradiation to October 5, 196
Comparison of Methods to Assess Adiposity in Middle-to-Older Adult Women
Poster from the 2015 Food & Nutrition Conference & Expo. Poster Session: Professional Skills; Nutrition Assessment; Medical Nutrition Therapy
Friction factor and heat transfer correlation for irradiated organic coolants
"September 1965."Series statement handwritten on cover"MIT-334-23 Chemistry."Also written as an M.S. theses written by the first author and advised by the second author, Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1966Includes bibliographical references (pages 163-165)M.I.T. DSR Project no. 9819Work performed for the Savannah River Operations Office, U.S. Atomic Energy Commission under contract no. AT(38-1)-33
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