4,590 research outputs found
Reconciling Statistical Models with Practical Experience of Reverberation Chambers
Presented are novel theoretical probability density functions (PDF) for the magnitude and phase of electromagnetic fields inside reverberation chambers (RC) operating in a dasiagood-but-imperfect regime. The derivation is based on considering two Gaussian random variables with mean values, variances and correlation between them that depart from the ideal assumptions. A multivariate approach using a complete joint Gaussian distribution of these variables is defined. Marginal distributions obtained by integration of this two-dimensional joint PDF are compared with theoretical PDFs for ideal situations, and significantly lower rejection rates are experienced for field data measured in real RCs. Additionally, these novel marginal PDFs are highly general since they are able to describe both ideal and non-ideal stirred fields
Secondary maxima in ozone profiles
Ozone profiles from balloon soundings as well as SAGEII ozone profiles were used to detect anomalous large ozone concentrations of ozone in the lower stratosphere. These secondary ozone maxima are found to be the result of differential advection of ozone-poor and ozone-rich air associated with Rossby wave breaking events. The frequency and intensity of secondary ozone maxima and their geographical distribution is presented. The occurrence and amplitude of ozone secondary maxima is connected to ozone variability and trend at Uccle and account for a large part of the total ozone and lower stratospheric ozone variability
Results of a FRSI material test under Space Shuttle ascent conditions in the Ames Research Center 9x7 foot supersonic wind tunnel (OS13). Space Shuttle aerothermodynamic data report
A test was conducted in the NASA/ARC 9 x 7 foot supersonic wind tunnel to verify the integrity of Felt Reusable Surface Insulation (FRSI) material in a panel flutter environment. A FRSI sample panel was subjected to the shocks, pressure gradients, and turbulence characteristics encountered at dynamic pressure 1.5 times the 3(sigma) dispersed trajectory flight conditions of the Space Shuttle. Static and fluctuating pressure data were obtained for Mach numbers ranging from 1.55 to 2.5 with dynamic pressures of 625 to 1250 psf. The FRSI panel suffered no appreciable damage as a result of the test
Adenovirus-Mediated Sensitization to the Cytotoxic Drugs Docetaxel and Mitoxantrone Is Dependent on Regulatory Domains in the E1ACR1 Gene-Region
Oncolytic adenoviruses have shown promising efficacy in clinical trials targeting prostate cancers that frequently develop resistance to all current therapies. The replication-selective mutants AdΔΔ and dl922–947, defective in pRb-binding, have been demonstrated to synergise with the current standard of care, mitoxantrone and docetaxel, in prostate cancer models. While expression of the early viral E1A gene is essential for the enhanced cell killing, the specific E1A-regions required for the effects are unknown. Here, we demonstrate that replicating mutants deleted in small E1A-domains, binding pRb (dl1108), p300/CBP (dl1104) and p400/TRRAP or p21 (dl1102) sensitize human prostate cancer cells (PC-3, DU145, 22Rv1) to mitoxantrone and docetaxel. Through generation of non-replicating mutants, we demonstrate that the small E1A12S protein is sufficient to potently sensitize all prostate cancer cells to the drugs even in the absence of viral replication and the E1A transactivating domain, conserved region (CR) 3. Furthermore, the p300/CBP-binding domain in E1ACR1 is essential for drug-sensitisation in the absence (AdE1A1104) but not in the presence of the E1ACR3 (dl1104) domain. AdE1A1104 also failed to increase apoptosis and accumulation of cells in G2/M. All E1AΔCR2 mutants (AdE1A1108, dl922–947) and AdE1A1102 or dl1102 enhance cell killing to the same degree as wild type virus. In PC-3 xenografts in vivo the dl1102 mutant significantly prolongs time to tumor progression that is further enhanced in combination with docetaxel. Neither dl1102 nor dl1104 replicates in normal human epithelial cells (NHBE). These findings suggest that additional E1A-deletions might be included when developing more potent replication-selective oncolytic viruses, such as the AdΔCR2-mutants, to further enhance potency through synergistic cell killing in combination with current chemotherapeutics
Can Regulatory Bodies Expect Efficient Help from Formal Methods?
In the context of EDEMOI - a French national project that proposed the use of semiformal and formal methods to infer the consistency and robustness of aeronautical regulations through the analysis of faithfully representative models- a methodology had been suggested (and applied) to different (safety and security-related) aeronautical regulations. This paper summarizes the preliminary results of this experience by stating which were the methodology s expected benefits, from a scientific point of view, and which are its useful benefits, from a regulatory body s point of view
The Interstellar Rubidium Isotope Ratio toward Rho Ophiuchi A
The isotope ratio, 85Rb/87Rb, places constraints on models of the
nucleosynthesis of heavy elements, but there is no precise determination of the
ratio for material beyond the Solar System. We report the first measurement of
the interstellar Rb isotope ratio. Our measurement of the Rb I line at 7800 A
for the diffuse gas toward rho Oph A yields a value of 1.21 +/- 0.30 (1-sigma)
that differs significantly from the meteoritic value of 2.59. The Rb/K
elemental abundance ratio for the cloud also is lower than that seen in
meteorites. Comparison of the 85Rb/K and 87Rb/K ratios with meteoritic values
indicates that the interstellar 85Rb abundance in this direction is lower than
the Solar System abundance. We attribute the lower abundance to a reduced
contribution from the r-process. Interstellar abundances for Kr, Cd, and Sn are
consistent with much less r-process synthesis for the solar neighborhood
compared to the amount inferred for the Solar System.Comment: 12 pages with 2 figures and 1 table; will appear in ApJ Letter
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