On the Development of a New Nonequilibrium Chemistry Model for Mars Entry

This paper represents a summary of results to date of an on-going effort at NASA Ames Research Center to develop a physics-based non-equilibrium model for hypersonic entry into the Martian atmosphere. Our approach is to first compute potential energy surfaces based on accurate solutions of the electronic Schroedinger equation and then use quasiclassical trajectory calculations to obtain reaction cross sections and rate coefficients based on these potentials. We have presented new rate coefficients for N2 dissociation and CO dissociation and exchange reactions. These results illustrate shortcomings with some of the rate coefficients in Parks original T-Tv model for Mars entries and with some of the 30-45 year old shock tube data. We observe that the shock tube experiments of CO + O dissociation did not adequately account for the exchange reaction that leads to formation of C + O2. This reaction is actually the primary channel for CO removal in the shock layer at temperatures below 10,000 K, because the reaction enthalpy for exchange is considerably lower than the comparable value for dissociation

Towards single particle imaging of human chromosomes at SACLA

Single particle imaging (SPI) is one of the front-page opportunities which were used to motivate the construction of the first x-ray free electron lasers (XFELs). SPI's big advantage is that it avoids radiation damage to biological samples because the diffraction takes place in femtosecond single shots before any atomic motion can take place in the sample, hence before the onset of radiation damage. This is the 'diffract before destruction' theme, destruction being assured from the high x-ray doses used. This article reports our collaboration's first attempt at SPI using the SACLA XFEL facility in June 2015. The report is limited to experience with the instrumentation and examples of data because we have not yet had time to invert them to images

Towards single particle imaging of human chromosomes at SACLA

Single particle imaging (SPI) is one of the front-page opportunities which were used to motivate the construction of the first x-ray free electron lasers (XFELs). SPI's big advantage is that it avoids radiation damage to biological samples because the diffraction takes place in femtosecond single shots before any atomic motion can take place in the sample, hence before the onset of radiation damage. This is the 'diffract before destruction' theme, destruction being assured from the high x-ray doses used. This article reports our collaboration's first attempt at SPI using the SACLA XFEL facility in June 2015. The report is limited to experience with the instrumentation and examples of data because we have not yet had time to invert them to images.112Ysciescopu

Verification of the indoor GPS system, by comparison with calibrated coordinates and by angular reference

This paper details work carried out to verify the dimensional measurement performance of the Indoor GPS (iGPS) system; a network of Rotary-Laser Automatic Theodolites (R-LATs). Initially tests were carried out to determine the angular uncertainties on an individual R-LAT transmitter-receiver pair. A method is presented of determining the uncertainty of dimensional measurement for a three dimensional coordinate measurement machine. An experimental procedure was developed to compare three dimensional coordinate measurements with calibrated reference points. The reference standard used to calibrate these reference points was a fringe counting interferometer with the multilateration technique employed to establish three dimensional coordinates. This is an extension of the established technique of comparing measured lengths with calibrated lengths. The method was found to be practical and able to establish that the expanded uncertainty of the basic iGPS system was approximately 1 mm at a 95% confidence level. Further tests carried out on a highly optimized version of the iGPS system have shown that the coordinate uncertainty can be reduced to 0.25 mm at a 95% confidence level

Discovery of a TiO emission band in the infrared spectrum of the S star NP Aurigae

We report on the discovery of an infrared emission band in the Spitzer spectrum of the S-type AGB star NP Aurigae that is caused by TiO molecules in the circumstellar environment. We modelled the observed emission to derive the temperature of the TiO molecules (\approx 600 K), an upper limit on the column density (\approx 10^17.25 cm^{-2}) and a lower limit on the spatial extent of the layer that contains these molecules. (\approx 4.6 stellar radii). This is the first time that this TiO emission band is observed. A search for similar emission features in the sample of S-type stars yielded two additional candidates. However, owing to the additional dust emission, the identification is less stringent. By comparing the stellar characteristics of NP Aur to those of the other stars in our sample, we find that all stars with TiO emission show large-amplitude pulsations, s-process enrichment, and a low C/O ratio. These characteristics might be necessary requirements for a star to show TiO in emission, but they are not sufficient.Comment: 4 pages, 4 figures, letter to the edito

Identification of the Beutler-Fano formula in eigenphase shifts and eigentime delays near a resonance

Eigenphase shifts and eigentime delays near a resonance for a system of one discrete state and two continua are shown to be functionals of the Beutler- Fano formulas using appropriate dimensionless energy units and line profile indices. Parameters responsible for the avoided crossing of eigenphase shifts and eigentime delays are identified. Similarly, parameters responsible for the eigentime delays due to a frame change are identified. With the help of new parameters, an analogy with the spin model is pursued for the S matrix and time delay matrix. The time delay matrix is shown to comprise three terms, one due to resonance, one due to a avoided crossing interaction, and one due to a frame change. It is found that the squared sum of time delays due to the avoided crossing interaction and frame change is unity.Comment: 17 pages, 3 figures, RevTe

Control of human endometrial stromal cell motility by PDGF-BB, HB-EGF and trophoblast-secreted factors

Human implantation involves extensive tissue remodeling at the fetal-maternal interface. It is becoming increasingly evident that not only trophoblast, but also decidualizing endometrial stromal cells are inherently motile and invasive, and likely contribute to the highly dynamic processes at the implantation site. The present study was undertaken to further characterize the mechanisms involved in the regulation of endometrial stromal cell motility and to identify trophoblast-derived factors that modulate migration. Among local growth factors known to be present at the time of implantation, heparin-binding epidermal growth factor-like growth factor (HB-EGF) triggered chemotaxis (directed locomotion), whereas platelet-derived growth factor (PDGF)-BB elicited both chemotaxis and chemokinesis (non-directed locomotion) of endometrial stromal cells. Supernatants of the trophoblast cell line AC-1M88 and of first trimester villous explant cultures stimulated chemotaxis but not chemokinesis. Proteome profiling for cytokines and angiogenesis factors revealed neither PDGF-BB nor HB-EGF in conditioned media from trophoblast cells or villous explants, while placental growth factor, vascular endothelial growth factor and PDGF-AA were identified as prominent secretory products. Among these, only PDGF-AA triggered endometrial stromal cell chemotaxis. Neutralization of PDGF-AA in trophoblast conditioned media, however, did not diminish chemoattractant activity, suggesting the presence of additional trophoblast-derived chemotactic factors. Pathway inhibitor studies revealed ERK1/2, PI3 kinase/Akt and p38 signaling as relevant for chemotactic motility, whereas chemokinesis depended primarily on PI3 kinase/Akt activation. Both chemotaxis and chemokinesis were stimulated upon inhibition of Rho-associated, coiled-coil containing protein kinase. The chemotactic response to trophoblast secretions was not blunted by inhibition of isolated signaling cascades, indicating activation of overlapping pathways in trophoblast-endometrial communication. In conclusion, trophoblast signals attract endometrial stromal cells, while PDGF-BB and HB-EGF, although not identified as trophoblast-derived, are local growth factors that may serve to fine-tune directed and non-directed migration at the implantation site

D'Annunzio sulla scena lirica: libretto o "Poema"?

Australia Direct Action climate change policy relies on purchasing greenhouse gas abatement from projects undertaking approved abatement activities. Management of soil organic carbon (SOC) in agricultural soils is an approved activity, based on the expectation that land use change can deliver significant changes in SOC. However, there are concerns that climate, topography and soil texture will limit changes in SOC stocks. This work analyses data from 1482 sites surveyed across the major agricultural regions of Eastern Australia to determine the relative importance of land use vs. other drivers of SOC. Variation in land use explained only 1.4% of the total variation in SOC, with aridity and soil texture the main regulators of SOC stock under different land uses. Results suggest the greatest potential for increasing SOC stocks in Eastern Australian agricultural regions lies in converting from cropping to pasture on heavy textured soils in the humid regions

Measurement of Mass and Width of the W Boson at LEP

We report on measurements of the mass and total decay width of the W boson with the L3 detector at LEP. W-pair events produced in $\mathrm{e^+e^-}$ interactions between 161 GeV and 183 GeV centre-of-mass energy are selected in a data sample corresponding to a total luminosity of 76.7 pb$^{-1}$. Combining all final states in W-pair production, the mass and total decay width of the W boson are determined to be $\mathrm{M_W}=80.61\pm0.15$ GeV and $\Gamma_{\mathrm{W}}=1.97\pm0.38$ GeV, respectively

Search for Heavy Neutral and Charged Leptons in e+^+e−^- Annihilation at s\sqrt{s} = 183 and 189 GeV

A search for unstable neutral and charged heavy leptons as well as for stable charged heavy leptons is performed at center-of-mass energies $\sqrt{s}$ = 183 and 189 GeV with the L3 detector at LEP. No evidence for their existence is found. We exclude neutral heavy leptons which couple to the electron, muon or tau family, of the Dirac type for masses below 92.4, 93.3 and 83.3 GeV, and of the Majorana type for masses below 81.8, 84.1 and 73.5 GeV, respectively. We exclude unstable charged heavy leptons for masses below 93.9 GeV for a wide range of the associated neutral heavy lepton mass. If the unstable charged heavy lepton decays to a light neutrino, we exclude masses below 92.4 GeV. The production of stable charged heavy leptons with mass less than 93.5 GeV is also excluded