The parity-violating (PV) asymmetry of inclusive π- production in electron scattering from a liquid deuterium target was measured at backward angles. The measurement was conducted as a part of the G0 ...experiment, at a beam energy of 360 MeV. The physics process dominating pion production for these kinematics is quasifree photoproduction off the neutron via the Δ0 resonance. In the context of heavy-baryon chiral perturbation theory, this asymmetry is related to a low-energy constant d(Δ)- that characterizes the parity-violating γNΔ coupling. Zhu et al. calculated d(Δ)- in a model benchmarked by the large asymmetries seen in hyperon weak radiative decays, and predicted potentially large asymmetries for this process, ranging from A(γ)-=-5.2 to +5.2 ppm. The measurement performed in this work leads to A(γ)-=-0.36±1.06±0.37±0.03 ppm (where sources of statistical, systematic and theoretical uncertainties are included), which would disfavor enchancements considered by Zhu et al. proportional to V(ud)/V(us). The measurement is part of a program of inelastic scattering measurements that were conducted by the G0 experiment, seeking to determine the N-Δ axial transition form factors using PV electron scattering.
The production of magnesium alloy WE43 was achieved by selective laser melting (SLM). The alloy was investigated after SLM, hot isostatic pressing (HIP), and solutionising heat treatment. The ...microstructure and corrosion behaviour of the specimens were carefully characterised, whilst assessed and contrast relative to the conventionally cast alloy counterpart. The SLM prepared specimens possess a unique microstructure comprising fine grains growing with a strong 0001 texture along the building direction with a low fraction of process-induced and metallurgical defects, reaching < 0.1 %, after optimising the SLM parameters and the HIP treatment. Electrochemical measurements demonstrated that the SLM prepared WE43 is cathodically more active as compared with its cast counterpart. It is proposed that this behaviour is due to a high density of zirconium-rich oxide particles uniformly distributed throughout the alloy microstructure as well as the alterations in the chemical composition of the solid-solution matrix originating from the high cooling rates of SLM. It was also noted that the oxide particles are mainly sourced by powder. The present results suggest that the corrosion of SLM prepared Mg alloys could be greatly improved once the influence of powder characteristics is further understood and controlled.
We have measured the beam-normal single-spin asymmetries in elastic scattering of transversely polarized electrons from the proton, and performed the first measurement in quasi-elastic scattering on ...the deuteron, at backward angles (lab scattering angle of 108 degrees) for Q^2 = 0.22 GeV^2/c^2 and 0.63GeV^2/c^2 at beam energies of 362 MeV and 687 MeV, respectively. Results for the proton are consistent with a model calculation which includes inelastic intermediate hadronic (piN) states. An estimate of the beam-normal single-spin asymmetry for the scattering from the neutron is made using a quasi-static deuterium approximation, and is also in agreement with theory.
NOνA, the NuMI Off-Axis νe Appearance experiment, will study νμ → νe oscillations characterized by the mixing angle θ13. Provided θ13 is large enough, NOνA may ultimately determine the ordering of ...the neutrino masses and measure CP violation in neutrino oscillations. A complementary pair of detectors will be constructed ∼14 mrad off beam axis to optimize the energy profile of the neutrinos. This system consists of a surface based 14 kTon liquid scintillatior tracking volume located 810km from the main injector source (NuMI) in Ash River, Minnesota and a smaller underground 222 Ton near detector at the Fermilab. The first neutrino signals at the Ash River Site are expected prior to the 2012 accelerator shutdown. In the meantime, a near detector surface prototype has been completed and neutrinos from two Fermilab sources have been observed using the same highly segmented PVC and liquid scintillator detector system that will be deployed in the full scale experiment. Design and initial performance characteristics of this prototype system are being fed back into the design for the full NOνA program.
We have measured parity-violating asymmetries in elastic electron-proton and quasielastic electron-deuteron scattering at Q2=0.22 and 0.63 GeV2. They are sensitive to strange quark contributions to ...currents in the nucleon and the nucleon axial-vector current. The results indicate strange quark contributions of approximately < 10% of the charge and magnetic nucleon form factors at these four-momentum transfers. We also present the first measurement of anapole moment effects in the axial-vector current at these four-momentum transfers.
Orbital surgery has always been disputed among specialists, mainly neurosurgeons, otorhinolaryngologists, maxillofacial surgeons and ophthalmologists. The orbit is a borderland between intra- and ...extracranial compartments; Krönlein's lateral orbitotomy and the orbitozygomatic infratemporal approach are the historical milestones of modern orbital-cranial surgery.
Since its first implementation, endoscopy has significantly impacted neurosurgery, changing perspectives and approaches to the skull base. Since its first application in 2009, transorbital endoscopic surgery opened the way for new surgical scenario, previously feasible only with extensive tissue dissection.
A PRISMA based literature search was performed to select the most relevant papers on the topic.
Here, we provide a narrative review on the current state and future trends in endoscopic orbital surgery.
This manuscript is a joint effort of the EANS frontiers committee in orbital tumors and the EANS skull base section.
•Orbital surgery is a frontier between different specialties: neurosurgeons, otorhinolaryngologists, maxillofacial surgeons, and ophthalmologists. Endoscopy opened a whole new scenario of surgical possibilities.•Trans-Orbital surgery seems to provide useful access to different intracranial compartments, previously reachable only via an extensive tissue dissection, with good functional and oncological outcomes.•Homogeneous nomenclature of approaches and anatomical landmarks, data consistency across studies, broad shared classifications and well-designed randomized clinical trials are strongly advocated.•Next years will be crucial to precise indications, techniques, outcomes and complications of trans-orbital endoscopy through data obtained from high-level scientific studies.•Specific and dedicated applications are needed for transorbital endoscopic surgery to incorporate this topic into the common neurosurgical knowledge of the new generations.
We have measured the beam-normal single-spin asymmetries in elastic scattering of transversely polarized electrons from the proton, and performed the first measurement in quasielastic scattering on ...the deuteron, at backward angles (lab scattering angle of 108°) for Q² = 0.22 GeV²/c² and 0.63 GeV²/c² at beam energies of 362 and 687 MeV, respectively. The asymmetry arises due to the imaginary part of the interference of the two-photon exchange amplitude with that of single-photon exchange. Results for the proton are consistent with a model calculation which includes inelastic intermediate hadronic (πN) states. An estimate of the beam-normal single-spin asymmetry for the scattering from the neutron is made using a quasistatic deuterium approximation, and is also in agreement with theory.
Intravitreal ranibizumab injections currently are the standard treatment for neovascular age-related macular degeneration (AMD). However, a broad range of response rates have been observed, the ...reasons for which are poorly understood. This pharmacogenetic study evaluated the impact of high-risk alleles in CFH, ARMS2, VEGFA, vascular endothelial growth factor (VEGF) receptor KDR, and genes involved in angiogenesis (LRP5, FZD4) on the response to ranibizumab treatment and on the age of treatment onset. In contrast to previous studies, the data were stratified according to the number of high-risk alleles to enable the study of the combined effects of these genotypes on the treatment response.
Case series study.
A cohort of 420 eyes of 397 neovascular AMD patients.
The change in visual acuity (VA) between baseline and after 3 ranibizumab injections was calculated. Genotyping of single nucleotide polymorphisms in the CFH, ARMS2, VEGFA, KDR, LPR5, and FZD4 genes was performed. Associations were assessed using linear mixed models.
The VA change after 3 ranibizumab injections and the age of neovascular disease onset.
After ranibizumab treatment, AMD patients without risk alleles in the CFH and ARMS2 genes (4.8%) demonstrated a mean VA improvement of 10 Early Treatment Diabetic Retinopathy Study (ETDRS) letters, whereas no VA improvement was observed in AMD patients with 4 CFH and ARMS2 risk alleles (6.9%; P = 0.014). Patients with 4 high-risk alleles in CFH and ARMS2 were 5.2 years younger than patients with 1 or 2 risk alleles, respectively (63.5%; P<0.0001). The mean age at which the first ranibizumab treatment was carried out among AMD patients with all 6 risk alleles in CFH, ARMS2, and VEGFA was 65.9 years (2%) versus 75.3 years in patients with 0 or 1 high-risk allele (8.8%; P = 0.001). After ranibizumab treatment, patients with 6 high-risk alleles demonstrated a mean VA loss of 10 ETDRS letters (P<0.0001).
This study evaluated the largest pharmacogenetic AMD cohort reported to date. A cumulative effect of high-risk alleles in CFH, ARMS2, and VEGFA seems to be associated with a younger age of onset in combination with poor response rates to ranibizumab treatment.
To analyze the temporal correlations of vascular endothelial growth factor (VEGF) suppression, morphologic recurrence of choroidal neovascularization (CNV), and visual acuity loss in eyes with ...exudative age-related macular degeneration (AMD) treated with ranibizumab.
Nonrandomized, prospective, clinical study.
Forty-seven eyes of 47 patients with exudative AMD undergoing intravitreal ranibizumab injections.
Aqueous humor specimens were taken before each intravitreal ranibizumab injection. Visual acuity testing, spectral domain optical coherence tomography (SD-OCT), and fundoscopy were performed before each injection. Vascular endothelial growth factor A was measured by Luminex multiplex bead analysis (Luminex Inc., Austin, TX).
Intraocular VEGF concentration, recurrence of CNV activity shown by SD-OCT, and vision loss.
Ranibizumab resulted in complete VEGF suppression within a mean period of 37.8 days (standard deviation SD ± 4.8 days; range, 26-49 days). Recurrences of CNV activity as determined by SD-OCT occurred 93.7 days (SD ± 69.9 days; range, 57-368 days) after the last ranibizumab treatment. The VEGF levels were never suppressed when a recurrence occurred. Functional recurrence (visual acuity) occurred 114.3 days (SD ± 81.4 days; range, 57-398 days) after previous treatment. The VEGF levels did not differ significantly between baseline and recurrence (69.3 pg/ml vs. 74.14 pg/ml; 95% confidence interval, -18.87 to 9.12).
A monthly intravitreal injection of 0.5 mg ranibizumab yields a durable VEGF inhibition. The recurrences of CNV as determined by SD-OCT are always preceded by a loss of intraocular VEGF suppression and usually followed by loss of visual acuity in the further course.
Strange Quark Contributions to Parity-Violating Asymmetries in the Backward Angle G0 Electron Scattering Experiment D. Androic, D. S. Armstrong, J. Arvieux†, S. L. Bailey, D. H. Beck, E. J. Beise, J. Benesch; F. Benmokhtar, L. Bimbot, J. Birchall, P. Bosted, H. Breuer, C. L. Capuano, Y.-C. Chao, A. Coppens; C. A. Davis, C. Ellis, G. Flores, G. Franklin, C. Furget, D. Gaskell, M. T. W. Gericke, J. Grames ...
Physical review letters,
01/2010, Letnik:
104, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We have measured parity-violating asymmetries in elastic electron-proton and quasielastic electron-deuteron scattering at Q2=0.22 and 0.63 GeV2. They are sensitive to strange quark contributions to ...currents in the nucleon and the nucleon axial-vector current. The results indicate strange quark contributions of ≲10% of the charge and magnetic nucleon form factors at these four-momentum transfers. We also present the first measurement of anapole moment effects in the axial-vector current at these four-momentum transfers.
PDF
