62 research outputs found
Cefiderocol for the Treatment of Adult and Pediatric Patients with Cystic Fibrosis and Achromobacter xylosoxidans Infections
Treatment options for Achromobacter xylosoxidans are limited. Eight cystic fibrosis patients with A. xylosoxidans were treated with 12 cefiderocol courses. Pretreatment in vitro resistance was seen in 3 of 8 cases. Clinical response occurred after 11 of 12 treatment courses. However, microbiologic relapse was observed after 11 of 12 treatment courses, notably without emergence of resistance
Phantom Divide Crossing with General Non-minimal Kinetic Coupling
We propose a model of dark energy consists of a single scalar field with a
general non-minimal kinetic couplings to itself and to the curvature. We study
the cosmological dynamics of the equation of state in this setup. The coupling
terms have the form and
where
and are coupling parameters and their dimensions depend on the type
of function . We obtain the conditions required for phantom divide
crossing and show numerically that a cosmological model with general
non-minimal derivative coupling to the scalar and Ricci curvatures can realize
such a crossing.Comment: 12 pages, 4 figures. Accepted for publication in Gen. Rel. Grav.
arXiv admin note: substantial text overlap with arXiv:1105.4967,
arXiv:1201.1627, and with arXiv:astro-ph/0610092 by other author
Slewing Mirror Telescope and the Data-Acquisition System for the UFFO-Pathfinder
The Ultra-Fast Flash Observatory (UFFO) aims to detect the earliest moment of Gamma-Ray
Bursts (GRBs) which is not well known, resulting into the enhancement of GRB mechanism
understanding. The pathfinder mission was proposed to be a scaled-down version of UFFO,
and only contains the UFFO Burst Alert & Trigger Telescope (UBAT) measuring the
X-ray/gamma-ray with the wide-field of view and the Slewing Mirror Telescope (SMT) with a
rapid-response for the UV/optical photons. Once the UBAT detects a GRB candidate with the
position accuracy of 10 arcmin, the SMT steers the UV/optical photons from the candidate
to the telescope by the fast rotatable mirror and provides the early UV/optical photons
measurements with 4 arcsec accuracy. The SMT has a modified Ritchey-Chrètien telescope
with the aperture size of 10 cm diameter including the rotatable mirror and the image
readout by the intensified charge-coupled device. There is a key board called the UFFO
Data Acquisition system (UDAQ) that manages the communication of each telescope and also
of the satellite and the UFFO overall operation. This pathfinder is designed and built
within the limited size and weight of ~20 kg and the low power consumption up to
~30 W. We will discuss the design and performance of the UFFO-pathfinder, and its
integration to the Lomonosov satellite
Development of Motorized Slewing Mirror Stage for the UFFO Project
The Ultra-Fast Flash Observatory (UFFO) is a space observatory for optical follow-ups of
gamma ray bursts (GRBs), aiming to explore the first 60 seconds of GRBs optical emission.
UFFO is utilized to catch early optical emissions from GRBs within few sec after trigger
using a Gimbal mirror which redirects the optical path rather than slewing entire
spacecraft. We have developed a 15 cm two-axis Gimbal mirror stage for the UFFO-Pathfinder
which is going to be on board the Lomonosov satellite which is to be launched in 2013. The
stage is designed for fast and accurate motion with given budgets of 3 kg of mass and 3
Watt of power. By employing stepping motors, the slewing mirror can rotate faster than 15
deg/sec so that objects in the UFFO coverage (60 deg × 60 deg) can be targeted in
~1 sec. The obtained targeting resolution is better 2 arcmin using a close-loop
control with high precision rotary encoder. In this presentation, we will discuss details
of design, manufacturing, space qualification tests, as well as performance tests
Ultra-Fast Flash Observatory: Fast Response Space Missions for Early Time Phase of Gamma Ray Bursts
One of the unexplored domains in the study of gamma-ray bursts (GRBs) is the early time
phase of the optical light curve. We have proposed Ultra-Fast Flash Observatory (UFFO) to
address this question through extraordinary opportunities presented by a series of small
space missions. The UFFO is equipped with a fast-response Slewing Mirror Telescope that
uses a rapidly moving mirror or mirror array to redirect the optical beam rather than
slewing the entire spacecraft or telescope to aim the optical instrument at the GRB
position. The UFFO will probe the early optical rise of GRBs with sub-second response, for
the first time, opening a completely new frontier in GRB and transient studies. Its fast
response measurements of the optical emission of dozens of GRB each year will provide
unique probes of the burst mechanism and test the prospect of GRB as a new standard
candle, potentially opening up the z > 10 universe. We describe the current limit in
early photon measurements, the aspects of early photon physics, our soon-to-be-launched
UFFO-pathfinder mission, and our next planned mission, the UFFO-100
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