Detection of plant stress through multispectral photography

There are no author-identified significant results in this report

How Sustainable Are North American Wood Supplies?

This paper analyzes the current wood supply estimates for North America. The result of the analysis casts doubts whether the North American supplies are sustainable. It is obvious that current estimates do not consider many of the aspects of sustainable forest management but are based on a concept of the availability of timber. It can be concluded that there is a lack of consistent national projections in both the USA and Canada. The North American analyses do not take into account that the wood supply issue is driven by the political economy and not only by the market economy. North America has a lot to gain if future analyses of the supply would be carried out based on a political economic concept

Quark Contributions to Nucleon Momentum and Spin from Domain Wall fermion calculations

We report contributions to the nucleon spin and momentum from light quarks calculated using dynamical domain wall fermions with pion masses down to 300 MeV and fine lattice spacing a=0.084 fm. Albeit without disconnected diagrams, we observe that spin and orbital angular momenta of both u and d quarks are opposite, almost canceling in the case of the d quark, which agrees with previous calculations using a mixed quark action. We also present the full momentum dependence of n=2 generalized form factors showing little variation with the pion mass.Comment: 7 pages, 5 figures, NT-LBNL-11-020, MIT-CTP-4323. Presented at the 29th International Symposium on Lattice Field Theory (Lattice 2011), Squaw Valley, California, 10-16 Jul 201

Geometric scaling in exclusive processes

We show that according to the present understanding of the energy evolution of the observables measured in deep-inelastic scattering, the photon-proton scattering amplitude has to exhibit geometric scaling at each impact parameter. We suggest a way to test it experimentally at HERA. A qualitative analysis based on published data is presented and discussed.Comment: 9 pages, 2 figures. v2: references added, some points clarifie

First Calculation of Hyperon Axial Couplings from Lattice QCD

In this work, we report the first lattice calculation of hyperon axial couplings, using the 2+1-flavor MILC configurations and domain-wall fermion valence quarks. Both the $\Sigma$ and $\Xi$ axial couplings are computed for the first time in lattice QCD. In particular we find that $g_{\Sigma\Sigma} = 0.450(21)_{\rm stat}(27)_{\rm syst}$ and $g_{\Xi\Xi} = -0.277(15)_{\rm stat}(19)_{\rm syst}$.Comment: 5 pages, 2 figure

Mobile air monitoring data-processing strategies and effects on spatial air pollution trends

The collection of real-time air quality measurements while in motion (i.e., mobile monitoring) is currently conducted worldwide to evaluate in situ emissions, local air quality trends, and air pollutant exposure. This measurement strategy pushes the limits of traditional data analysis with complex second-by-second multipollutant data varying as a function of time and location. Data reduction and filtering techniques are often applied to deduce trends, such as pollutant spatial gradients downwind of a highway. However, rarely do mobile monitoring studies report the sensitivity of their results to the chosen data-processing approaches. The study being reported here utilized 40 h (> 140 000 observations) of mobile monitoring data collected on a roadway network in central North Carolina to explore common data-processing strategies including local emission plume detection, background estimation, and averaging techniques for spatial trend analyses. One-second time resolution measurements of ultrafine particles (UFPs), black carbon (BC), particulate matter (PM), carbon monoxide (CO), and nitrogen dioxide (NO₂) were collected on 12 unique driving routes that were each sampled repeatedly. The route with the highest number of repetitions was used to compare local exhaust plume detection and averaging methods. Analyses demonstrate that the multiple local exhaust plume detection strategies reported produce generally similar results and that utilizing a median of measurements taken within a specified route segment (as opposed to a mean) may be sufficient to avoid bias in near-source spatial trends. A time-series-based method of estimating background concentrations was shown to produce similar but slightly lower estimates than a location-based method. For the complete data set the estimated contributions of the background to the mean pollutant concentrations were as follows: BC (15%), UFPs (26%), CO (41%), PM_2.5-10 (45%), NO₂ (57%), PM₁₀ (60%), PM_2.5 (68%). Lastly, while temporal smoothing (e.g., 5 s averages) results in weak pair-wise correlation and the blurring of spatial trends, spatial averaging (e.g., 10 m) is demonstrated to increase correlation and refine spatial trends

The Learning Curve in Percutaneous Repair of Paravalvular Prosthetic Regurgitation An Analysis of 200 Cases

ObjectivesThis study sought to assess the learning curve for percutaneous repair of paravalvular prosthetic regurgitation.BackgroundPercutaneous repair of prosthetic paravalvular regurgitation is a complex procedure. There is a paucity of data on the professional experience and tools needed to achieve optimal clinical outcomes.MethodsWe examined the chronological experience of 200 patients (age 66 ± 13 years; 57% men) who underwent percutaneous closure of paravalvular prosthetic regurgitation at our institution. A sequence number of the patient was assigned as a continuous variable for analysis.ResultsA total of 243 paravalvular defects (74% mitral; 26% aortic) were treated. Device delivery was successful in 92% with an average procedural time of 139 ± 47 min. The 30-day rate of major adverse cardiovascular events was 7%. With increased case experience and adoption of dedicated imaging and catheter techniques, there were decreases in procedural time, fluoroscopy time, contrast volume administered, length of hospital stay, and major adverse cardiovascular events. Procedural success remained unchanged throughout the experience. The predominant reason for procedural failure was prosthetic leaflet impingement, which accounted for 9 of 21 failed cases.ConclusionsIn this single-center experience, there was evidence of a learning curve that occurred with the adoption of dedicated techniques for catheter delivery and echocardiographic imaging. In experienced operators, the potential for prosthetic leaflet impingement is the predominant limitation of the procedure. These data have implications for physician training and performance in complex structural heart disease interventions

Nucleon Electromagnetic Form Factors from Lattice QCD using 2+1 Flavor Domain Wall Fermions on Fine Lattices and Chiral Perturbation Theory

We present a high-statistics calculation of nucleon electromagnetic form factors in $N_f=2+1$ lattice QCD using domain wall quarks on fine lattices, to attain a new level of precision in systematic and statistical errors. Our calculations use $32^3 \times 64$ lattices with lattice spacing a=0.084 fm for pion masses of 297, 355, and 403 MeV, and we perform an overdetermined analysis using on the order of 3600 to 7000 measurements to calculate nucleon electric and magnetic form factors up to $Q^2 \approx$ 1.05 GeV$^2$. Results are shown to be consistent with those obtained using valence domain wall quarks with improved staggered sea quarks, and using coarse domain wall lattices. We determine the isovector Dirac radius $r_1^v$, Pauli radius $r_2^v$ and anomalous magnetic moment $\kappa_v$. We also determine connected contributions to the corresponding isoscalar observables. We extrapolate these observables to the physical pion mass using two different formulations of two-flavor chiral effective field theory at one loop: the heavy baryon Small Scale Expansion (SSE) and covariant baryon chiral perturbation theory. The isovector results and the connected contributions to the isoscalar results are compared with experiment, and the need for calculations at smaller pion masses is discussed.Comment: 44 pages, 40 figure

Nucleon structure with two flavors of dynamical domain-wall fermions

We present a numerical lattice quantum chromodynamics calculation of isovector form factors and the first few moments of the isovector structure functions of the nucleon. The calculation employs two degenerate dynamical flavors of domain-wall fermions, resulting in good control of chiral symmetry breaking. Non-perturbative renormalization of the relevant quark currents is performed where necessary. The inverse lattice spacing, $a^{-1}$, is about 1.7 GeV. We use degenerate up and down dynamical quark masses around 1, 3/4 and 1/2 the strange quark mass. The physical volume of the lattice is about $(1.9{fm})^3$. The ratio of the isovector vector to axial charges, $g_A/g_V$, trends a bit lower than the experimental value as the quark mass is reduced toward the physical point. We calculate the momentum-transfer dependences of the isovector vector, axial, induced tensor and induced pseudoscalar form factors. The Goldberger-Treiman relation holds at low momentum transfer and yields a pion-nucleon coupling, $g_{\pi NN} = 15.5(1.4)$, where the quoted error is only statistical. We find that the flavor non-singlet quark momentum fraction $_{u-d}$ and quark helicity fraction $_{\Delta u-\Delta d}$ overshoot their experimental values after linear chiral extrapolation. We obtain the transversity, $_{\delta u-\delta d} = 0.93(6)$ in $\bar{\rm MS}$ at 2 GeV and a twist-3 polarized moment, $d_1$, appears small, suggesting that the Wandzura-Wilczek relation holds approximately. We discuss the systematic errors in the calculation, with particular attention paid to finite-volume effects, excited-state contamination, and chiral extrapolations.Comment: 28 pages in two columns; 37 figures, 12 table