893 research outputs found
Cost-Effectiveness Evaluation of Swiss Agri-Environmental Measures on Sector Level
Abstract
This paper focuses on non-linear programming models and their suitability for ex-ante evaluations of agri-environmental policies on sector level. An approach is presented to compare organic farming payments as a multi-objective policy, with other, more targeted agri-environmental policies in Switzerland. The Swiss version of the comparative static sector-consistent farm group model FARMIS is able to group the sector’s farms into organic and non-organic farms and optimise them separately.
CH-FARMIS is expanded with three modules particularly for this study: a) allowing for the simulation of uptake; b) integrating life cycle assessment data for energy use, eutrophication and biodiversity; and c) estimating the policy and farm-group-specific public expenditure, including transaction costs.
This paper illustrates the functions of the model, shows preliminary energy use calculations for the German Agricultural Sector and discusses the advantages and limitations of the approach
Photothermal infrared thermography applied to the identification of thin layer thermophysical properties
Abstract: The aim of the present work is the thermal non-destructive characterisation of layers at the surface of metals. The sample is sinusoidally heated by means of an argon ion laser and a focal plane array infrared camera (CEDIP IRC 320-4 LW) is used to measure the temperature variations at the surface of the layer. A numerical lock-in procedure allows the detection of very weak temperature variations at the surface of the sample, down to a few mK when working from the acquisition of hundreds of images, yielding amplitude and absolute phase maps for modulation frequencies ranging from 0.1 Hz to 1000 Hz. An inverse procedure uses the Gauss-Newton parameter estimation method, in order to identify the thermal conductivity and the optical absorption coefficient of the layer. Confidence intervals on the parameters can also be estimated by the inverse procedure. More particular attention is devoted to the study of the sensitivity coefficients, as functions of the frequency range and of the radial range along the profiles, in order to optimise the identification procedure
Indications for the Nonexistence of Three-Neutron Resonances near the Physical Region
The pending question of the existence of three-neutron resonances near the
physical energy region is reconsidered. Finite rank neutron-neutron forces are
used in Faddeev equations, which are analytically continued into the unphysical
energy sheet below the positive real energy axis. The trajectories of the
three-neutron S-matrix poles in the states of total angular momenta and parity
J^\pi=1/2 +- and J^\pi= 3/2 +- are traced out as a function of artificial
enhancement factors of the neutron-neutron forces. The final positions of the
S-matrix poles removing the artificial factors are found in all cases to be far
away from the positive real energy axis, which provides a strong indication for
the nonexistence of nearby three-neutron resonances. The pole trajectories
close to the threshold E=0 are also predicted out of auxiliary generated
three-neutron bound state energies using the Pad\'e method and agree very well
with the directly calculated ones.Comment: 20 pages, 7 Postscript figures, fig.1 is corrected, uses relax.st
Performance of Different Diagnostic PD-L1 Clones in Head and Neck Squamous Cell Carcinoma
Background: The approval of immune checkpoint inhibitors in combination with specific diagnostic biomarkers presents new challenges to pathologists as tumor tissue needs to be tested for expression of programmed death-ligand 1 (PD-L1) for a variety of indications. As there is currently no requirement to use companion diagnostic assays for PD-L1 testing in Germany different clones are used in daily routine. While the correlation of staining results has been tested in various entities, there is no data for head and neck squamous cell carcinomas (HNSCC) so far.
Methods: We tested five different PD-L1 clones (SP263, SP142, E1L3N, 22-8, 22C3) on primary HNSCC tumor tissue of 75 patients in the form of tissue microarrays. Stainings of both immune and tumor cells were then assessed and quantified by pathologists to simulate real-world routine diagnostics. The results were analyzed descriptively and the resulting staining pattern across patients was further investigated by principal component analysis and non-negative matrix factorization clustering.
Results: Percentages of positive immune and tumor cells varied greatly. Both the resulting combined positive score as well as the eligibility for certain checkpoint inhibitor regimens was therefore strongly dependent on the choice of the antibody. No relevant co-clustering and low similarity of relative staining patterns across patients was found for the different antibodies.
Conclusions: Performance of different diagnostic anti PD-L1 antibody clones in HNSCC is less robust and interchangeable compared to reported data from other tumor entities. Determination of PD-L1 expression is critical for therapeutic decision making and may be aided by back-to-back testing of different PD-L1 clones
Consistent alpha-cluster description of the 12C (0^+_2) resonance
The near-threshold 12C (0^+_2) resonance provides unique possibility for fast
helium burning in stars, as predicted by Hoyle to explain the observed
abundance of elements in the Universe. Properties of this resonance are
calculated within the framework of the alpha-cluster model whose two-body and
three-body effective potentials are tuned to describe the alpha - alpha
scattering data, the energies of the 0^+_1 and 0^+_2 states, and the
0^+_1-state root-mean-square radius. The extremely small width of the 0^+_2
state, the 0_2^+ to 0_1^+ monopole transition matrix element, and transition
radius are found in remarkable agreement with the experimental data. The
0^+_2-state structure is described as a system of three alpha-particles
oscillating between the ground-state-like configuration and the elongated chain
configuration whose probability exceeds 0.9
The reaction dynamics of the 16O(e,e'p) cross section at high missing energies
We measured the cross section and response functions (R_L, R_T, and R_LT) for
the 16O(e,e'p) reaction in quasielastic kinematics for missing energies 25 <=
E_miss <= 120 MeV at various missing momenta P_miss <= 340 MeV/c. For 25 <
E_miss < 50 MeV and P_miss \approx 60 MeV/c, the reaction is dominated by
single-nucleon knockout from the 1s1/2-state. At larger P_miss, the
single-particle aspects are increasingly masked by more complicated processes.
For E_miss > 60 MeV and P_miss > 200 MeV/c, the cross section is relatively
constant. Calculations which include contributions from pion exchange currents,
isobar currents and short-range correlations account for the shape and the
transversity but only for half of the magnitude of the measured cross section.Comment: 6 pages, 4 figures, submitted to Phys Rev Lett, formatting error
fixe
High-precision Studies of the He(e,ep) Reaction at the Quasielastic Peak
Precision studies of the reaction He(e,ep) using the
three-spectrometer facility at the Mainz microtron MAMI are presented. All data
are for quasielastic kinematics at MeV/c. Absolute cross
sections were measured at three electron kinematics. For the measured missing
momenta range from 10 to 165 MeV/c, no strength is observed for missing
energies higher than 20 MeV. Distorted momentum distributions were extracted
for the two-body breakup and the continuum. The longitudinal and transverse
behavior was studied by measuring the cross section for three photon
polarizations. The longitudinal and transverse nature of the cross sections is
well described by a currently accepted and widely used prescription of the
off-shell electron-nucleon cross-section. The results are compared to modern
three-body calculations and to previous data.Comment: 4 pages, 3 figures. Submitted for publication in Phys. Rev. Let
The ratio of proton's electric to magnetic form factors measured by polarization transfer
The ratio of the proton's elastic electromagnetic form factors was obtained
by measuring the transverse and longitudinal polarizations of recoiling protons
from the elastic scattering of polarized electrons with unpolarized protons.
The ratio of the electric to magnetic form factor is proportional to the ratio
of the transverse to longitudinal recoil polarizations. The ratio was measured
over a range of four-momentum transfer squared between 0.5 and 3.5 GeV-squared.
Simultaneous measurement of transverse and longitudinal polarizations in a
polarimeter provides good control of the systematic uncertainty. The results
for the ratio of the proton's electric to magnetic form factors show a
systematic decrease with increasing four momentum squared, indicating for the
first time a marked difference in the spatial distribution of charge and
magnetization currents in the proton.Comment: 5 pages, 2 figures, version of paper after corrections due to
referees comments and shortened by removing one figure for Physical Review
Letter
Virtual Compton Scattering and the Generalized Polarizabilities of the Proton at Q^2=0.92 and 1.76 GeV^2
Virtual Compton Scattering (VCS) on the proton has been studied at Jefferson
Lab using the exclusive photon electroproduction reaction (e p --> e p gamma).
This paper gives a detailed account of the analysis which has led to the
determination of the structure functions P_LL-P_TT/epsilon and P_LT, and the
electric and magnetic generalized polarizabilities (GPs) alpha_E(Q^2) and
beta_M(Q^2) at values of the four-momentum transfer squared Q^2= 0.92 and 1.76
GeV^2. These data, together with the results of VCS experiments at lower
momenta, help building a coherent picture of the electric and magnetic GPs of
the proton over the full measured Q^2-range, and point to their non-trivial
behavior.Comment: version 2: modified according to PRC Editor's and Referee's
recommendations. Archival paper for the E93-050 experiment at JLab Hall A. 28
pages, 23 figures, 5 cross-section tables. To be submitted to Phys.Rev.
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