332 research outputs found
Tests of General relativity with planetary orbits and Monte Carlo simulations
Based on the new developped planetary ephemerides INPOP13c, determinations of
acceptable intervals of General Relativity violation in considering
simultaneously the PPN parameters , PPN , the flattening of the
sun and time variation of the gravitational mass of the sun
are obtained in using Monte Carlo simulation coupled with basic genetic
algorithm. Possible time variations of the gravitational constant G are also
deduced. Discussions are lead about the better choice of indicators for the
goodness-of-fit for each run and limits consistent with general relativity are
obtained simultaneously.Comment: submitte
Gravity tests with INPOP planetary ephemerides
In this paper, we present several gravity tests made in using the last
INPOP08 planetary ephemerides. We first propose two methods to estimate the PPN
parameter and its correlated value, the Sun J2 and we discuss the
correlation between the Sun J2 and the mass of the asteroid ring. We estimate
possible advance in the planet perihelia. In the end we show that no constant
acceleration larger than 1/4 the Pioneer anomaly can affect the planets of our
solar system.Comment: 11 pages. submitted to proceedings of IAU symposium 264 "Relativity
in Fundamental Astronomy: Dynamics, Reference Frames and Data analysis
Optimization of the fixed-flexion knee radiograph
SummaryPurposeTo develop a user-friendly method of achieving optimal radiographs for measurement of joint space width of the knee with minimal radiation exposure. In order to accomplish this the X-ray technologist must (1) be able to identify the anterior and posterior rims of the tibial plateau at a variety of X-ray head angles and (2) be able to choose the direction to adjust the head angle to get a better view based on the criteria for acceptable radiographs.MethodsWe have developed a training manual and materials to instruct investigators and radiology technologists in a method that uses a commercially available Plexiglas positioning frame (Synaflexer™) and standard X-ray equipment to achieve optimal X-rays with regard to tibial plateau alignment of the knee. This should be accomplished with four or fewer radiographs.ResultsOptimized radiographs for joint space width measurements are achieved without the need for fluoroscopy or foot maps.ConclusionsThis method is readily understood and instituted by radiology technologists in the field
The INPOP10a planetary ephemeris and its applications in fundamental physics
International audienceCompared to the previous INPOP versions, the INPOP10a planetary and lunar ephemeris has several improvements. For the planets of our solar system, no big change was brought in the dynamics but improvements were implemented in the fitting process, the data sets used in the fit and in the selection of fitted parameters. We report here the main characteristics of the planetary part of INPOP10a like the fit of the product of the Solar mass with the gravitational constant (GM) instead of the astronomical unit. Determinations of PPN parameters as well as adjustments of the Sun J2 and of asteroid masses are also presented. New advances of nodes and perihelia of planets were also estimated and are given here. As for INPOP08, INPOP10a provides to the user, positions and velocities of the planets, the moon, the rotation angles of the Earth and the Moon as well as TT-TDB chebychev polynomials at http://www.imcce.fr/inpo
INPOP08, a 4-D planetary ephemeris: From asteroid and time-scale computations to ESA Mars Express and Venus Express contributions
The latest version of the planetary ephemerides developed at the Paris
Observatory and at the Besancon Observatory is presented here. INPOP08 is a
4-dimension ephemeris since it provides to users positions and velocities of
planets and the relation between TT and TDB. Investigations leading to improve
the modeling of asteroids are described as well as the new sets of observations
used for the fit of INPOP08. New observations provided by the European Space
Agency (ESA) deduced from the tracking of the Mars Express (MEX) and Venus
Express (VEX) missions are presented as well as the normal point deduced from
the Cassini mission. We show the huge impact brought by these observations in
the fit of INPOP08, especially in terms of Venus, Saturn and Earth-Moon
barycenter orbits.Comment: 14 pages. submitted to A&A. accepted in A&
Evolution of INPOP planetary ephemerides and Bepi-Colombo simulations
We give here a detailed description of the latest INPOP planetary ephemerides
INPOP20a. We test the sensitivity of the Sun oblateness determination obtained
with INPOP to different models for the Sun core rotation. We also present new
evaluations of possible GRT violations with the PPN parameters ,
and . With a new method for selecting acceptable alternative
ephemerides we provide conservative limits of about and
for and respectively using the
present day planetary data samples. We also present simulations of Bepi-Colombo
range tracking data and their impact on planetary ephemeris construction. We
show that the use of future BC range observations should improve these
estimates, in particular . Finally, interesting perspectives for the
detection of the Sun core rotation seem to be reachable thanks to the BC
mission and its accurate range measurements in the GRT frame.Comment: Proceedings of the IAU Symposium 364 "Multi-scale dynamics of space
objects
The CD14+HLA-DRlo/neg Monocyte: An Immunosuppressive Phenotype That Restrains Responses to Cancer Immunotherapy
Recent successes in cancer immunotherapy have been tempered by sub-optimal clinical responses in the majority of patients. The impaired anti-tumor immune responses observed in these patients are likely a consequence of immune system dysfunction contributed to by a variety of factors that include, but are not limited to, diminished antigen presentation/detection, leukopenia, a coordinated network of immunosuppressive cell surface proteins, cytokines and cellular mediators. Monocytes that have diminished or no HLA-DR expression, called CD14+HLA-DRlo/neg monocytes, have emerged as important mediators of tumor-induced immunosuppression. These cells have been grouped into a larger class of suppressive cells called myeloid derived suppressor cells (MDSCs) and are commonly referred to as monocytic myeloid derived suppressor cells. CD14+HLA-DRlo/neg monocytes were first characterized in patients with sepsis and were shown to regulate the transition from the inflammatory state to immune suppression, ultimately leading to immune paralysis. These immunosuppressive monocytes have also recently been shown to negatively affect responses to PD-1 and CTLA-4 checkpoint inhibition, CAR-T cell therapy, cancer vaccines, and hematopoietic stem cell transplantation. Ultimately, the goal is to understand the role of these cells in the context of immunosuppression not only to facilitate the development of targeted therapies to circumvent their effects, but also to potentially use them as a biomarker for understanding disparate responses to immunotherapeutic regimens. Practical aspects to be explored for development of CD14+HLA-DRlo/neg monocyte detection in patients are the standardization of flow cytometric gating methods to assess HLA-DR expression, an appropriate quantitation method, test sample type, and processing guidances. Once detection methods are established that yield consistently reproducible results, then further progress can be made toward understanding the role of CD14+HLA-DRlo/neg monocytes in the immunosuppressive state
Seismic stratigraphy and sediment cores reveal lake-level fluctuations in Lake Iznik (NW Turkey) over the past ∼70 ka
Our study aims to understand the palaeohydrological history of Lake Iznik and unravel the complex interplay between climatic, tectonic, and environmental factors that have shaped this Turkish basin. Through the analysis of seismic stratigraphy and sediment cores, we reveal a significant lowstand, indicating a lake level 60 m lower than today at ∼70 ka BP. Subsequently, a major phase of stepwise transgression is evidenced by 13 buried palaeoshorelines between ∼70 and 45 ka BP. From 45 to ∼10 ka cal BP, strong currents controlled the sedimentation in the lake, as evidenced by the occurrence of contourite drifts. Between ∼14 and 10 ka cal. BP, a major lowstand indicating a drier climate interrupted the current-controlled sedimentation regime. From ∼10 ka cal. BP, the subsequent increase in lake level occurred at the same time as the reconnection between the Mediterranean and Black seas. Archaeological evidence, including submerged structures of a basilica, establishes a link between lake-level changes and human settlement during the last millennium. The level of Lake Iznik has since continued to fluctuate due to climate change, tectonic events, and human activity
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