645 research outputs found
Space shuttle navigation analysis. Volume 2: Baseline system navigation
Studies related to the baseline navigation system for the orbiter are presented. The baseline navigation system studies include a covariance analysis of the Inertial Measurement Unit calibration and alignment procedures, postflight IMU error recovery for the approach and landing phases, on-orbit calibration of IMU instrument biases, and a covariance analysis of entry and prelaunch navigation system performance
Space shuttle navigation analysis
A detailed analysis of space shuttle navigation for each of the major mission phases is presented. A covariance analysis program for prelaunch IMU calibration and alignment for the orbital flight tests (OFT) is described, and a partial error budget is presented. The ascent, orbital operations and deorbit maneuver study considered GPS-aided inertial navigation in the Phase III GPS (1984+) time frame. The entry and landing study evaluated navigation performance for the OFT baseline system. Detailed error budgets and sensitivity analyses are provided for both the ascent and entry studies
Quantum Fields on the Groenewold-Moyal Plane: C, P, T and CPT
We show that despite the inherent non-locality of quantum field theories on
the Groenewold-Moyal (GM) plane, one can find a class of , ,
and invariant theories. In particular, these are theories
without gauge fields or with just gauge fields and no matter fields. We also
show that in the presence of gauge fields, one can have a field theory where
the Hamiltonian is and invariant while the -matrix
violates and .
In non-abelian gauge theories with matter fields such as the electro-weak and
sectors of the standard model of particle physics, , ,
and the product of any pair of them are broken while
remains intact for the case . (Here , : coordinate functions,
constant.) When ,
it contributes to breaking also and . It is known that the
-matrix in a non-abelian theory depends on only through
. The -matrix is frame dependent. It breaks (the identity
component of the) Lorentz group. All the noncommutative effects vanish if the
scattering takes place in the center-of-mass frame, or any frame where
, but not otherwise. and are good symmetries of the theory in this special case.Comment: 18 pages, 1 figure, revised, 2 references adde
Disposition and residues of marbofloxacin in eggs of laying hens
Marbofloxacin belongs to the group of fluoroquinolones, used exclusively in domestic animals. This study was carried out with the purpose of studying the temporal disposition of marbofloxacin in edible compartments of the egg after administration of 1, 52 mg/kg of marbofloxacin in drinking water for 11 consecutive days in hens in posture peak and average weight of 1,91±0,25 kg. Birds were housed in individual cages under controlled light conditions, ambient temperature, relative humidity, water and balanced feed ad libitum. After the administration, eggs were collected daily and immediately separated into albumen and yolk, identified per bird/day and stored at-20°C until analysis. The preparative assay consisted in extraction of the analyte using 200 mg of yolk or albumen, as appropriate, in deionized water, homogenizing solution and enrofloxacin solution as internal standard. Separation and quantification were performed by HPLC by reverse phase isocratic elution with fluorescence detector, mobile phase composed of water, acetonitrile and triethylamine adjusted to pH 3. According to the peak areas of known concentrations, the concentrations of the test samples were calculated by simple linear regression. The established marbofloxacin levels are higher and more persistent in the yolk than in albumen, reaching 8 and 9 days, respectively. The disposition characteristics observed with marbofloxacin are compatible with the physico-chemical properties of the antimicrobial with the respective compartments of the egg and the time required for its formation. Data obtained from marbofloxacin depletion in egg compartments were analyzed using the EMEA WT 1.4 software and conjecturing a rigorous MRL (0,001 µg/kg), a withdrawal period of 13 and 17 days was estimated, for albumen and yolk, respectively.Fil: Errecalde, Carlos. Universidad Nacional de Río Cuarto. Facultad de Agronomía y Veterinaria; ArgentinaFil: Urzúa Pizarro, Natala Francisca. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto; ArgentinaFil: Prieto, G.. Universidad Nacional de Río Cuarto; ArgentinaFil: Luders, C.. Universidad Catolica de Temuco.; ChileFil: Liboa, Rosendo Anibal. Universidad Nacional de Río Cuarto; ArgentinaFil: Gramaglia, Romina Andrea. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; Argentin
Quantum Fields on the Groenewold-Moyal Plane
We give an introductory review of quantum physics on the noncommutative
spacetime called the Groenewold-Moyal plane. Basic ideas like star products,
twisted statistics, second quantized fields and discrete symmetries are
discussed. We also outline some of the recent developments in these fields and
mention where one can search for experimental signals.Comment: 50 pages, 3 figures. v2: published versio
T and CPT Symmetries in Entangled Neutral Meson Systems
Genuine tests of an asymmetry under T and/or CPT transformations imply the
interchange between in-states and out-states. I explain a methodology to
perform model-indepedent separate measurements of the three CP, T and CPT
symmetry violations for transitions involving the decay of the neutral meson
systems in B- and {\Phi}-factories. It makes use of the quantum-mechanical
entanglement only, for which the individual state of each neutral meson is not
defined before the decay of its orthogonal partner. The final proof of the
independence of the three asymmetries is that no other theoretical ingredient
is involved and that the event sample corresponding to each case is different
from the other two. The experimental analysis for the measurements of these
three asymmetries as function of the time interval {\Delta}t > 0 between the
first and second decays is discussed, as well as the significance of the
expected results. In particular, one may advance a first observation of true,
direct, evidence of Time-Reserval-Violation in B-factories by many standard
deviations from zero, without any reference to, and independent of,
CP-Violation. In some quantum gravity framework the CPT-transformation is
ill-defined, so there is a resulting loss of particle-antiparticle identity.
This mechanism induces a breaking of the EPR correlation in the entanglement
imposed by Bose statistics to the neutral meson system, the so-called
{\omega}-effect. I present results and prospects for the {\omega}-parameter in
the correlated neutral meson-antimeson states.Comment: Proc. DISCRETE 2010, Symposium on Prospects in the Physics of
Discrete Symmetries, December 2010, Rom
Normal tau polarisation as a sensitive probe of CP violation in chargino decay
CP violation in the spin-spin correlations in chargino production and
subsequent two-body decay into a tau and a tau-sneutrino is studied at the ILC.
From the normal polarisation of the tau, an asymmetry is defined to test the
CP-violating phase of the higgsino mass parameter \mu. Asymmetries of more than
\pm70% are obtained, also in scenarios with heavy first and second generation
sfermions. Bounds on the statistical significances of the CP asymmetries are
estimated. As a result, the normal tau polarisation in the chargino decay is
one of the most sensitive probes to constrain or measure the phase \phi_\mu at
the ILC, motivating further detailed experimental studies.Comment: 20 pages, 10 figures, gzipped tar fil
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Searching for life with rovers: exploration methods and science results from the 2004 field campaign of the “Life in the Atacama” project and applications to future Mars Missions
LITA develops and field tests a long-range automated rover and a science payload to search for microbial life in the Atacama. The Atacama's evolution provides a unique training ground for designing and testing exploration strategies and life detection methods for the search for life on Mars
First Production and Detection of Cold Antihydrogen Atoms
The ATHENA experiment recently produced the first atoms of cold antihydrogen.
This paper gives a brief review of how this was achieved.Comment: Invited talk at Int. Conf. on Low Energy Antiprotons 2003 (LEAP03),
to be published in NIM
Regional Grey Matter Structure Differences between Transsexuals and Healthy Controls-A Voxel Based Morphometry Study.
Gender identity disorder (GID) refers to transsexual individuals who feel that their assigned biological gender is incongruent with their gender identity and this cannot be explained by any physical intersex condition. There is growing scientific interest in the last decades in studying the neuroanatomy and brain functions of transsexual individuals to better understand both the neuroanatomical features of transsexualism and the background of gender identity. So far, results are inconclusive but in general, transsexualism has been associated with a distinct neuroanatomical pattern. Studies mainly focused on male to female (MTF) transsexuals and there is scarcity of data acquired on female to male (FTM) transsexuals. Thus, our aim was to analyze structural MRI data with voxel based morphometry (VBM) obtained from both FTM and MTF transsexuals (n = 17) and compare them to the data of 18 age matched healthy control subjects (both males and females). We found differences in the regional grey matter (GM) structure of transsexual compared with control subjects, independent from their biological gender, in the cerebellum, the left angular gyrus and in the left inferior parietal lobule. Additionally, our findings showed that in several brain areas, regarding their GM volume, transsexual subjects did not differ significantly from controls sharing their gender identity but were different from those sharing their biological gender (areas in the left and right precentral gyri, the left postcentral gyrus, the left posterior cingulate, precuneus and calcarinus, the right cuneus, the right fusiform, lingual, middle and inferior occipital, and inferior temporal gyri). These results support the notion that structural brain differences exist between transsexual and healthy control subjects and that majority of these structural differences are dependent on the biological gender
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