Flow field prediction and analysis study for project RAM B3 Final report

Flow field properties in shock layer surrounding Ram B3 vehicl

Poisson transition rates from time-domain measurements with finite bandwidth

In time-domain measurements of a Poisson two-level system, the observed transition rates are always smaller than those of the actual system, a general consequence of finite measurement bandwidth in an experiment. This underestimation of the rates is significant even when the measurement and detection apparatus is ten times faster than the process under study. We derive here a quantitative form for this correction using a straightforward state-transition model that includes the detection apparatus, and provide a method for determining a system's actual transition rates from bandwidth-limited measurements. We support our results with computer simulations and experimental data from time-domain measurements of quasiparticle tunneling in a single-Cooper-pair transistor.Comment: 4 pages, 5 figure

Light-cone sum rules for B→πB \to \pi form factors revisited

We reconsider and update the QCD light-cone sum rules for $B\to \pi$ form factors. The gluon radiative corrections to the twist-2 and twist-3 terms in the correlation functions are calculated. The $\bar{MS}$ $b$-quark mass is employed, instead of the one-loop pole mass used in the previous analyses. The light-cone sum rule for $f^+_{B\pi}(q^2)$ is fitted to the measured $q^2$-distribution in $B\to \pi l \nu_l$, fixing the input parameters with the largest uncertainty: the Gegenbauer moments of the pion distribution amplitude. For the $B\to \pi$ vector form factor at zero momentum transfer we predict $f^+_{B\pi}(0)= 0.26^{+0.04}_{-0.03}$. Combining it with the value of the product $|V_{ub}f^+_{B\pi}(0)|$ extracted from experiment, we obtain $|V_{ub}|=(3.5\pm 0.4\pm 0.2\pm 0.1) \times 10^{-3}$. In addition, the scalar and penguin $B\to \pi$ form factors $f^0_{B\pi}(q^2)$ and $f^T_{B\pi}(q^2)$ are calculated.Comment: 33 pages, 7 figures, one figure and a few comments added, version to appear in JHE

EFFECTIVE COSTS AND CHEMICAL USE IN U.S. AGRICULTURAL PRODUCTION: BENEFITS AND COSTS OF USING THE ENVIRONMENT AS A "FREE" INPUT

This study uses a cost-function-based model of production processes in U.S. agriculture to represent producers' input and output decisions, and the implied costs of reductions in risk associated with leaching and runoff from agricultural chemical use. The model facilitates evaluation of the statistical significance of measured shadow values for "bad" outputs, and their input- and output-specific components, with a focus on the impacts on pesticide demand and its quality and quantity aspects. The shadow values of risk reduction are statistically significant, and imply increased demand for effective pesticides over time that stem largely from improvements in quality due to embodied technology, and that vary substantively by region.Environmental Economics and Policy, Farm Management,

Heavy-to-light transition form factors and their relations in light-cone QCD sum rules

The improved light-cone QCD sum rules by using chiral current correlator is systematically reviewed and applied to the calculation of all the heavy-to-light form factors, including all the semileptonic and penguin ones. By choosing suitable chiral currents, the light-cone sum rules for all the form factors are greatly simplified and depend mainly on one leading twist distribution amplitude of the light meson. As a result, relations between these form factors arise naturally. At the considered accuracy these relations reproduce the results obtained in the literature. Moreover, since the explicit dependence on the leading twist distribution amplitudes is preserved, these relations may be more useful to simulate the experimental data and extract the information on the distribution amplitude.Comment: 1+16 pages, no figure

Exomars entry and descent science

The entry, descent and landing of ExoMars offer a rare (once-per-mission) opportunity to perform in situ investigation of the martian environment over a wide altitude range. We present an initial assessment of the atmospheric science that can be performed using sensors of the Entry, Descent and Landing System (EDLS), over and above the expected engineering information. This is intended to help fulfill the concept of an Atmospheric Parameters Package (APP), as mentioned in the ExoMars draft Science Management Plan [ESA, 2005]. Mars' atmosphere is highly variable in time and space, due to phenomena including inertio-gravity waves, thermal tide effects, dust, solar wind conditions, and diurnal, seasonal and topographic effects. Atmospheric profile measurements, drawing on heritage from the Huygens Atmospheric Structure Instrument (HASI), which encountered Titan's atmosphere in 2005 [1], should allow us to address questions of the martian atmosphere's structure, dynamics and variability

A Review of the Agronomic Characteristics of Endophyte-Free and Endophyte-Infected Tall Fescue

Agronomic differences between endophyte- (Acremonium coenophialum Morgan Jones and Gams) free and endophyte-infected tall fescue (Festuca arundinacea Schreb.) exist, and should be considered when implementing a management strategy. Although dry matter yield of tall fescue does not generally appear to be influenced by endophyte infection status, endophyte infection has been shown to improve seedling performance and survival, is associated with insect and nematode resistance, drought resistance, improved nitrogen assimilation, and higher seed set. Considering all biologically valuable characters of the endophyte-tall fescue relationship, survival of endophyte-infected tall fescue is probably better than that of endophyte-free tall fescue, especially in drought- or heat-stressed environments. Despite problems which growers have reported in establishing stand; of endophyte-free tall fescue varieties, there is still a decided advantage to seeding endophyte-free tall fescue because of improved livestock performance. However, greater attention to management is needed, particularly during the establishment year. Good seedbed preparation, including fertility improvements, should be stressed for endophyte-free tall fescue. Since endophyte-free tall fescue seedlings are not as vigorous as endophyte-infected tall fescue seedlings, using other grasses as nurse crops, or seeding with clovers, is not recommended when establishing new stands. Environmental or imposed stress on newly established endophyte-free tall fescue stands should be avoided by selecting optimum planting dates, and limiting livestock access. Top growth should not be grazed or clipped shorter than 3-4 in. (7-10 cm) during the first year of growth

Structure of the axial-vector meson Ds1(2460)D_{s1}(2460) and the strong coupling constant gDs1D∗Kg_{D_{s1} D^* K} with the light-cone QCD sum rules

In this article, we take the point of view that the charmed axial-vector meson $D_{s1}(2460)$ is the conventional $c\bar{s}$ meson and calculate the strong coupling constant $g_{D_{s1} D^* K}$ in the framework of the light-cone QCD sum rules approach. The numerical values of strong coupling constants $g_{D_{s1} D^* K}$ and $g_{D_{s0} D K}$ are very large, and support the hadronic dressing mechanism. Just like the scalar mesons $f_0(980)$ and $a_0(980)$, the scalar meson $D_{s0}(2317)$ and axial-vector meson $D_{s1}(2460)$ may have small $c\bar{s}$ kernels of the typical $c\bar{s}$ meson size, the strong couplings to the hadronic channels (or the virtual mesons loops) may result in smaller masses than the conventional $c\bar{s}$ mesons in the constituent quark models, and enrich the pure $c\bar{s}$ states with other components.Comment: 17 pages, 7 figures, revised version. In the first version, I take the value $f_{D_{s1}}= (0.25\pm0.02)GeV$ in numerical calculation, in the revised version, I take a small value $f_{D_{s1}}=(0.225 \pm0.020)GeV$, the value of the strong coupling constant is also change