242 research outputs found
The role of SLR and LLR in relativity
While General Relativity has been adopted as the standard theory of relativity, there are alternative theories, with important implications for gravitational physics, which can only be discounted with tests of sufficient accuracy. In addition to its contributions to lunar and solar system dynamics, Lunar Laser Ranging, in combination with other solar system data continues to refine some important limits. Satellite laser ranging tracking of geodetic satellites can provide similar tests, but the accuracy is usually limited by gravitational and nongravitational perturbations
The Attraction of Foreign Manufacturing Investments: Investment Promotion and Agglomeration Economies
We study Japanese investments between 1980 and 1992 to assess the effectiveness of state promotion efforts in light of strong agglomeration economies in Japanese investment. Two policy variables are consistently shown to influence the location of investment - foreign trade zones and labor subsidies. We use simulations to explore the impact these policies had on the geographic distribution of Japanese investment. The simulations reveal that in aggregate promotion programs largely offset each other; however, unilateral withdrawal of promotion causes individual states to lose substantial amounts of foreign investment.
Precision orbit determination of altimetric satellites
The ability to determine accurate global sea level variations is important to both detection and understanding of changes in climate patterns. Sea level variability occurs over a wide spectrum of temporal and spatial scales, and precise global measurements are only recently possible with the advent of spaceborne satellite radar altimetry missions. One of the inherent requirements for accurate determination of absolute sea surface topography is that the altimetric satellite orbits be computed with sub-decimeter accuracy within a well defined terrestrial reference frame. SLR tracking in support of precision orbit determination of altimetric satellites is significant. Recent examples are the use of SLR as the primary tracking systems for TOPEX/Poseidon and for ERS-1 precision orbit determination. The current radial orbit accuracy for TOPEX/Poseidon is estimated to be around 3-4 cm, with geographically correlated orbit errors around 2 cm. The significance of the SLR tracking system is its ability to allow altimetric satellites to obtain absolute sea level measurements and thereby provide a link to other altimetry measurement systems for long-term sea level studies. SLR tracking allows the production of precise orbits which are well centered in an accurate terrestrial reference frame. With proper calibration of the radar altimeter, these precise orbits, along with the altimeter measurements, provide long term absolute sea level measurements. The U.S. Navy's Geosat mission is equipped with only Doppler beacons and lacks laser retroreflectors. However, its orbits, and even the Geosat orbits computed using the available full 40-station Tranet tracking network, yield orbits with significant north-south shifts with respect to the IERS terrestrial reference frame. The resulting Geosat sea surface topography will be tilted accordingly, making interpretation of long-term sea level variability studies difficult
Elevated expression of polymorphonuclear leukocyte elastase in breast cancer tissue is associated with tamoxifen failure in patients with advanced disease
A new laser-ranged satellite for General Relativity and space geodesy: I. An introduction to the LARES2 space experiment
We introduce the LARES 2 space experiment recently approved by the Italian Space Agency (ASI). The LARES 2 satellite is planned for launch in 2019 with the new VEGA C launch vehicle of ASI, ESA and ELV. The orbital analysis of LARES 2 experiment will be carried out by our international science team of experts in General Relativity, theoretical physics, space geodesy and aerospace engineering. The main objectives of the LARES 2 experiment are gravitational and fundamental physics, including accurate measurements of General Relativity, in particular a test of frame-dragging aimed at achieving an accuracy of a few parts in a thousand, i.e., aimed at improving by about an order of magnitude the present state-of-the-art and forthcoming tests of this general relativistic phenomenon. LARES 2 will also achieve determinations in space geodesy. LARES 2 is an improved version of the LAGEOS 3 experiment, proposed in 1984 to measure frame-dragging and analyzed in 1989 by a joint ASI and NASA study
Fundamental Physics and General Relativity with the LARES and LAGEOS satellites
Current observations of the universe have strengthened the interest to
further test General Relativity and other theories of fundamental physics.
After an introduction to the phenomenon of frame-dragging predicted by
Einstein's theory of General Relativity, with fundamental astrophysical
applications to rotating black holes, we describe the past measurements of
frame-dragging obtained by the LAGEOS satellites and by the dedicated Gravity
Probe B space mission. We also discuss a test of String Theories of
Chern-Simons type that has been carried out using the results of the LAGEOS
satellites. We then describe the LARES space experiment. LARES was successfully
launched in February 2012 to improve the accuracy of the tests of
frame-dragging, it can also improve the test of String Theories. We present the
results of the first few months of observations of LARES, its orbital analyses
show that it has the best agreement of any other satellite with the
test-particle motion predicted by General Relativity. We finally briefly report
the accurate studies and the extensive simulations of the LARES space
experiment, confirming an accuracy of a few percent in the forthcoming
measurement of frame-dragging.Comment: To be publihed in Nuclear Physics. arXiv admin note: substantial text
overlap with arXiv:1306.1826, arXiv:1211.137
The prognostic value of polymorphonuclear leukocyte elastase in patients with primary breast cancer
A variety of serine proteases, including urokinase-type plasminogen
activator (uPA), plasmin,and polymorphonuclear leukocyte elastase (PMN-E),
have been implicated in the processes of tumor cell invasion and
metastasis. Besides degrading of matrix proteins, PMN-E has been shown to
be able to cleave and inactivate plasminogen activator inhibitor-1
(PAI-1), the main inhibitor of uPA, and alpha2-antiplasmin, the natural
inhibitor of plasmin, thus enabling an uncontrolled matrix degradation by
the fibrinolytic enzymes. Because only limited data are available on a
relationship between the tumor level of PMN-E and prognosis in primary
breast cancer patients, in the present study we have measured with an
ELISA the levels of PMN-E (in complex with alpha1-proteinase inhibitor) in
cytosolic extracts of 1143 primary breast tumors. Levels of complexed
PMN-E have been correlated with the lengths of metastasis-free survival
(MFS), relapse-free survival, and overall survival, and a comparison was
made with data previously obtained for uPA and PAI-1. Our results show
that patients with a high PMN-E level in their primary tumor had a rapid
relapse and an early death compared with patients with a low tumor level
of PMN-E. This held true for node-negative and node-positive subgroups of
patients as well. The relationship of PMN-E with a poor prognosis was
especially obvious during short-term follow-up (0-60 months). In Cox
multivariate regression analysis, corrected for the traditional prognostic
factors, PMN-E was an independent prognostic factor, and high levels of
PMN-E were associated with a poor MFS [hazard ratio (HR), 1.63; 95%
confidence interval (CI), 1.23-2.16; P < 0.001], relapse-free survival
(HR, 1.45; 95% CI, 1.10-1.89; P = 0.01), and overall survival (HR, 1.64;
95% CI, 1.20-2.23; P = 0.003). Furthermore, in all three multivariate
models, PMN-E still added significantly to the model after the additional
inclusion of the uPA. PMN-E was an independent prognostic factor for MFS
even in the multivariate analysis including the traditional clinical
prognostic factors and the strong established biochemical prognostic
factors uPA and PAI-1. Our present study suggests that PMN-E is associated
with breast cancer metastasis, and knowledge of the tumor PMN-E status
might be helpful in selecting the appropriate individualized (adjuvant)
treatment for patients with breast cancer
A Test of General Relativity Using the LARES and LAGEOS Satellites and a GRACE Earth's Gravity Model
We present a test of General Relativity, the measurement of the Earth's
dragging of inertial frames. Our result is obtained using about 3.5 years of
laser-ranged observations of the LARES, LAGEOS and LAGEOS 2 laser-ranged
satellites together with the Earth's gravity field model GGM05S produced by the
space geodesy mission GRACE. We measure ,
where is the Earth's dragging of inertial frames normalized to its
General Relativity value, 0.002 is the 1-sigma formal error and 0.05 is the
estimated systematic error mainly due to the uncertainties in the Earth's
gravity model GGM05S. Our result is in agreement with the prediction of General
Relativity.Comment: 13 pages, 4 figures, published on EPJ
GRACE Measurements of Mass Variability in the Earth System
Monthly gravity field estimates made by the twin Gravity Recovery and Climate Experiment (GRACE) satellites have a geoid height accuracy of 2 to 3 millimeters at a spatial resolution as small as 400 kilometers. The annual cycle in the geoid variations, up to 10 millimeters in some regions, peaked predominantly in the spring and fall seasons. Geoid variations observed over South America that can be largely attributed to surface water and groundwater changes show a clear separation between the large Amazon watershed and the smaller watersheds to the north. Such observations will help hydrologists to connect processes at traditional length scales (tens of kilometers or less) to those at regional and global scales
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