2,151 research outputs found
"The 'Ge' is in the Church and 'Our Parents are Playing Muslim': Performance, Identity and Resistance among the Dan in Postcolonial Cote d'Ivoire"
This article is posted with the full permission of the publisher
Masks and Music, Spirit and Sports: Gunyege in Performance
This chapter was posted with the permission of the publisher
The 1993 Celebration of Martin Luther King, Jr. Day in Bloomington, Indiana: Tradition, Interpretation, and Conflicts of Identity
This article is posted with the permission of the publisher
Context Switching with Multiple Register Windows: A RISC Performance Study
Although previous studies have shown that a large file of overlapping register windows can greatly reduce procedure call/return overhead, the effects of register windows in a multiprogramming environment are poorly understood. This paper investigates the performance of multiprogrammed, reduced instruction set computers (RISCs) as a function of window management strategy. Using an analytic model that reflects context switch and procedure call overheads, we analyze the performance of simple, linearly self-recursive programs. For more complex programs, we present the results of a simulation study. These studies show that a simple strategy that saves all windows prior to a context switch, but restores only a single window following a context switch, performs near optimally
About Starobinsky inflation
It is believed that soon after the Planck era, space time should have a
semi-classical nature. According to this, the escape from General Relativity
theory is unavoidable. Two geometric counter-terms are needed to regularize the
divergences which come from the expected value. These counter-terms are
responsible for a higher derivative metric gravitation. Starobinsky idea was
that these higher derivatives could mimic a cosmological constant. In this work
it is considered numerical solutions for general Bianchi I anisotropic
space-times in this higher derivative theory. The approach is ``experimental''
in the sense that there is no attempt to an analytical investigation of the
results. It is shown that for zero cosmological constant , there are
sets of initial conditions which form basins of attraction that asymptote
Minkowski space. The complement of this set of initial conditions form basins
which are attracted to some singular solutions. It is also shown, for a
cosmological constant that there are basins of attraction to a
specific de Sitter solution. This result is consistent with Starobinsky's
initial idea. The complement of this set also forms basins that are attracted
to some type of singular solution. Because the singularity is characterized by
curvature scalars, it must be stressed that the basin structure obtained is a
topological invariant, i.e., coordinate independent.Comment: Version accepted for publication in PRD. More references added, a few
modifications and minor correction
shapecoder: a new method for visual quantification of body mass index in young children
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141494/1/ijpo12202_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141494/2/ijpo12202.pd
A Regional Bolus Tracking and Real-time B Calibration Method for Hyperpolarized C MRI
Purpose: Acquisition timing and B calibration are two key factors that
affect the quality and accuracy of hyperpolarized C MRI. The goal of
this project was to develop a new approach using regional bolus tracking to
trigger Bloch-Siegert B mapping and real-time B calibration based on
regional B measurements, followed by dynamic imaging of hyperpolarized
metabolites in vivo.
Methods: The proposed approach was implemented on a system which allows
real-time data processing and real-time control on the sequence. Real-time
center frequency calibration upon the bolus arrival was also added. The
feasibility of applying the proposed framework for in vivo hyperpolarized
C imaging was tested on healthy rats, tumor-bearing mice and a healthy
volunteer on a clinical 3T scanner following hyperpolarized
[1-C]pyruvate injection. Multichannel receive coils were used in the
human study.
Results: Automatic acquisition timing based on either regional bolus peak or
bolus arrival was achieved with the proposed framework. Reduced blurring
artifacts in real-time reconstructed images were observed with real-time center
frequency calibration. Real-time computed B scaling factors agreed with
real-time acquired B maps. Flip angle correction using B maps results
in a more consistent quantification of metabolic activity (i.e,
pyruvate-to-lactate conversion, k). Experiment recordings are provided
to demonstrate the real-time actions during the experiment.
Conclusion: The proposed method was successfully demonstrated on animals and
a human volunteer, and is anticipated to improve the efficient use of the
hyperpolarized signal as well as the accuracy and robustness of hyperpolarized
C imaging
Development of a model for marburgvirus based on severe-combined immunodeficiency mice
The filoviruses, Ebola (EBOV) and Marburg (MARV), cause a lethal hemorrhagic fever. Human isolates of MARV are not lethal to immmunocompetent adult mice and, to date, there are no reports of a mouse-adapted MARV model. Previously, a uniformly lethal EBOV-Zaire mouse-adapted virus was developed by performing 9 sequential passages in progressively older mice (suckling to adult). Evaluation of this model identified many similarities between infection in mice and nonhuman primates, including viral tropism for antigen-presenting cells, high viral titers in the spleen and liver, and an equivalent mean time to death. Existence of the EBOV mouse model has increased our understanding of host responses to filovirus infections and likely has accelerated the development of countermeasures, as it is one of the only hemorrhagic fever viruses that has multiple candidate vaccines and therapeutics. Here, we demonstrate that serially passaging liver homogenates from MARV-infected severe combined immunodeficient (scid) mice was highly successful in reducing the time to death in scid mice from 50–70 days to 7–10 days after MARV-Ci67, -Musoke, or -Ravn challenge. We performed serial sampling studies to characterize the pathology of these scid mouse-adapted MARV strains. These scid mouse-adapted MARV models appear to have many similar properties as the MARV models previously developed in guinea pigs and nonhuman primates. Also, as shown here, the scid-adapted MARV mouse models can be used to evaluate the efficacy of candidate antiviral therapeutic molecules, such as phosphorodiamidate morpholino oligomers or antibodies
KELT-8b: A highly inflated transiting hot Jupiter and a new technique for extracting high-precision radial velocities from noisy spectra
We announce the discovery of a highly inflated transiting hot Jupiter
discovered by the KELT-North survey. A global analysis including constraints
from isochrones indicates that the V = 10.8 host star (HD 343246) is a mildly
evolved, G dwarf with K, , , an inferred mass
M, and radius
R. The planetary companion has mass , radius
, surface gravity , and density
g cm. The planet is on a roughly
circular orbit with semimajor axis AU and
eccentricity . The best-fit linear ephemeris is
BJD and
days. This planet is one of the most inflated of all known transiting
exoplanets, making it one of the few members of a class of extremely low
density, highly-irradiated gas giants. The low stellar and large
implied radius are supported by stellar density constraints from follow-up
light curves, plus an evolutionary and space motion analysis. We also develop a
new technique to extract high precision radial velocities from noisy spectra
that reduces the observing time needed to confirm transiting planet candidates.
This planet boasts deep transits of a bright star, a large inferred atmospheric
scale height, and a high equilibrium temperature of
K, assuming zero albedo and perfect heat redistribution, making it one of the
best targets for future atmospheric characterization studies.Comment: Submitted to ApJ, feedback is welcom
Gattini 2010: Cutting Edge Science at the Bottom of the World
The high altitude Antarctic sites of Dome A and the South Pole offer intriguing locations for future large scale optical astronomical
Observatories. The Gattini project was created to measure the optical
sky brightness, large area cloud cover and aurora of the winter-time
sky above such high altitude Antarctic sites. The Gattini-DomeA camera
was installed on the PLATO instrument module as part of the Chinese-led
traverse to the highest point on the Antarctic plateau in January 2008.
This single automated wide field camera contains a suite of Bessel
photometric filters (B, V, R) and a long-pass red filter for the
detection and monitoring of OH emission. We have in hand one complete
winter-time dataset (2009) from the camera that was recently returned
in April 2010.
The Gattini-South Pole UV camera is a wide-field optical camera that in
2011 will measure for the first time the UV properties of the
winter-time sky above the South Pole dark sector. This unique dataset
will consist of frequent images taken in both broadband U and B filters
in addition to high resolution (R similar to 5000) long slit
spectroscopy over a narrow bandwidth of the central field. The camera
is a proof of concept for the 2m-class Antarctic Cosmic Web Imager
telescope, a dedicated experiment to directly detect and map the
redshifted lyman alpha fluorescence or Cosmic Web emission we believe
possible due to the unique geographical qualities of the site.
We present the current status of both projects
- …