5,637 research outputs found
Environmental, developmental, and genetic factors controlling root system architecture
A better understanding of the development and architecture of roots is essential to develop strategies to increase crop yield and optimize agricultural land use. Roots control nutrient and water uptake, provide anchoring and mechanical support and can serve as important storage organs. Root growth and development is under tight genetic control and modulated by developmental cues including plant hormones and the environment. This review focuses on root architecture and its diversity and the role of environment, nutrient, and water as well as plant hormones and their interactions in shaping root architecture
Wide-angle elastic scattering and color randomization
Baryon-baryon elastic scattering is considered in the independent scattering
(Landshoff) mechanism. It is suggested that for scattering at moderate
energies, direct and interchange quark channels contribute with equal color
coefficients because the quark color is randomized by soft gluon exchange
during the hadronization stage. With this assumption, it is shown that the
ratio of cross sections at CM angle
decreases from a high energy value of R_{\pbar p / pp} \approx 1/2.7, down to
R_{\pbar p / pp} \approx 1/28, compatible with experimental data at moderate
energies. This sizable fall in the ratio seems to be characteristic of the
Landshoff mechanism, in which changes at the quark level have a strong effect
precisely because the hadronic process occurs via multiple quark scatterings.
The effect of color randomization on the angular distribution of proton-proton
elastic scattering and the cross section ratio is also discussed.Comment: 18 pages, latex2e, 4 uuencoded figures, include
Schiff Theorem and the Electric Dipole Moments of Hydrogen-Like Atoms
The Schiff theorem is revisited in this work and the residual - and
-odd electron--nucleus interaction, after the shielding takes effect, is
completely specified. An application is made to the electric dipole moments of
hydrogen-like atoms, whose qualitative features and systematics have important
implication for realistic paramagnetic atoms.Comment: 3 pages. Contribution to PANIC05, Particles and Nuclei International
Conference, Santa Fe, New Mexico, Oct. 24-28, 200
Constraints on T-Odd, P-Even Interactions from Electric Dipole Moments
We construct the relationship between nonrenormalizable,effective,
time-reversal violating (TV) parity-conserving (PC) interactions of quarks and
gauge bosons and various low-energy TVPC and TV parity-violating (PV)
observables. Using effective field theory methods, we delineate the scenarious
under which experimental limits on permanent electric dipole moments (EDM's) of
the electron, neutron, and neutral atoms as well as limits on TVPC observables
provide the most stringent bounds on new TVPC interactions. Under scenarios in
which parity invariance is restored at short distances, the one-loop EDM of
elementary fermions generate the most severe constraints. The limits derived
from the atomic EDM of Hg are considerably weaker. When parity symmetry
remains broken at short distances, direct TVPC search limits provide the least
ambiguous bounds. The direct limits follow from TVPC interactions between two
quarks.Comment: 43 pages, 9 figure
Nucleon Structure and Parity-Violating Electron Scattering
We review the area of strange quark contributions to nucleon structure. In
particular, we focus on current models of strange quark vector currents in the
nucleon and the associated parity-violating elastic electron scattering
experiments from which vector- and axial-vector currents are extractedComment: 40 pages including 7 figures; review article to be published in Int.
J. Mod. Phys.
Film cooling following injection through inclined circular tubes
Film cooling following air injection through inclined flat plate holes into turbulent boundary laye
The Vector Analyzing Power in Elastic Electron-Proton Scattering
We compute the vector analyzing power (VAP) for the elastic scattering of
transversely polarized electrons from protons at low energies using an
effective theory of electrons, protons, and photons. We study all contributions
through second order in , where and are the electron energy and
nucleon mass, respectively. The leading order VAP arises from the imaginary
part of the interference of one- and two-photon exchange amplitudes.
Sub-leading contributions are generated by the nucleon magnetic moment and
charge radius as well as recoil corrections to the leading-order amplitude.
Working to , we obtain a prediction for that is free of
unknown parameters and that agrees with the recent measurement of the VAP in
backward angle scattering.Comment: 24 pages, 11 figures. Typos fixe
A glimpse behind the organisational curtain: A dramaturgical analysis exploring the ways healthcare staff engage with online patient feedback ‘front’ and ‘backstage’ at three hospital Trusts in England
Healthcare staff are encouraged to use feedback from their patients to inform service and quality improvement. Receiving patient feedback via online channels is a relatively new phenomenon that has rarely been conceptualised. Further, the implications of a wide, varied and unknown(able) audience being able to view and interact with online patient feedback are yet to be understood. We applied a theoretical lens of dramaturgy to a large ethnographic dataset, collected across three NHS Trusts during 2019/2020. We found that organisations demonstrated varying levels of ‘preparedness to perform’ online, from invisibility through to engaging in public conversation with patients within a wider mission for transparency. Restrictive ‘cast lists’ of staff able to respond to patients was the hallmark of one organisation, whereas another devolved responding responsibility amongst a wide array of multidisciplinary staff. The visibility of patient-staff interactions had the potential to be culturally disruptive, dichotomously invoking either apprehensions of reputational threat or providing windows of opportunity. We surmise that a transparent and conversational feedback response frontstage aligns with the ability to better prioritise backstage improvement. Legitimising the autonomous frontstage activity of diverse staff groups may help shift organisational culture, and gradually ripple outwards a shared responsibility for transparent improvement
PCN10 ARE FURTHER STUDIES OF BREAST CANCER TUMOR MARKERS TO DETECT RECURRENCE WORTHWHILE? A VALUE OF RESEARCH ANALYSIS
Cuello, Ramon (escultor)Primer pla de l'obra. Davant de la casa on
vivia l'escultor a Sants hi havia hagut una fonda
on paraven les diligències que unien
l'interior de Catalunya amb el port de
Barcelona. De metall, mesura 2,58 x
0,80 x 0,80 metres
Photon Shot Noise Dephasing in the Strong-Dispersive Limit of Circuit QED
We study the photon shot noise dephasing of a superconducting transmon qubit
in the strong-dispersive limit, due to the coupling of the qubit to its readout
cavity. As each random arrival or departure of a photon is expected to
completely dephase the qubit, we can control the rate at which the qubit
experiences dephasing events by varying \textit{in situ} the cavity mode
population and decay rate. This allows us to verify a pure dephasing mechanism
that matches theoretical predictions, and in fact explains the increased
dephasing seen in recent transmon experiments as a function of cryostat
temperature. We investigate photon dynamics in this limit and observe large
increases in coherence times as the cavity is decoupled from the environment.
Our experiments suggest that the intrinsic coherence of small Josephson
junctions, when corrected with a single Hahn echo, is greater than several
hundred microseconds.Comment: 5 pages, 4 figures; includes Supporting Online Material of 6 pages
with 5 figure
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