Model studies of timber shell roofs.

The effects of four types of fastening and of scaling on the properties of a timber shell membrane were studied. The membrane was a three layer type made of ex 4 x 1 in. T & G radiata pine boards, the centre layer running at right angles to the outer layers. The fastenings were three densities of nailing and one of nail-gluing. Timber properties were characterised by grading modulus (g.m.) which was the stiffness of prototype boards on the flat under centre point loading over a 3 ft span while the fastenings were characterised by the load-slip behaviour of representative joints. The joint behaviour showed little correlation with g.m. Prototype and 1/5 scale model elements were tested in compression shear, bending and torsion and elastic constants were computed. The various constants were affected to different degrees by the four types of fastening according to the level of stress carried by the fastening under the various element loadings. The model similitude obtained in the elements was good when this was based on g.m., the load-slip behaviour of representative joints and the weight of glue spread per unit area of glueline. Two 1/5 scale model cylindrical timber shells were built and tested, one nailed and the other nail-glued. Their deflections were about twice those calculated by a simplified analysis for orthotropic shells. Their relative behaviour was similar to the relative behaviour of the model elements in shear which suggests that the discrepancy between calculated and observed deflections arose from shear deformation which the analysis ignored

Association of coronary vessel characteristics with outcome in patients with percutaneous coronary interventions with incomplete revascularization

© 2017 American Medical Association. All rights reserved. IMPORTANCE Many studies have compared outcomes for incomplete revascularization (IR) among patients undergoing percutaneous coronary interventions (PCI), but little is known about whether outcomes are related to the nature of the IR. OBJECTIVE To determine whether some coronary vessel characteristics are associated with worse outcomes in patients with PCI with IR. DESIGN, SETTING, AND PARTICIPANTS New York\u27s PCI registrywas used to examine mortality (median follow-up, 3.4 years) as a function of the number of vessels that were incompletely revascularized, the stenosis in those vessels, and whether the proximal left anterior descending artery was incompletely revascularized after controlling for other factors associated with mortality for patients with and without ST-elevationmyocardial infarction (STEMI). This was a multicenter study (all nonfederal PCI hospitals in New York State) that included 41 639 New York residents with multivessel coronary artery disease undergoing PCI in New York State between January 1, 2010, and December 31, 2012. EXPOSURES Percutaneous coronary interventions, with complete and incomplete revascularization. MAIN OUTCOMES AND MEASURES Medium-term mortality. RESULTS For patients with STEMI, the mean age was 62.8 years; 26.2%were women, 11.9% were Hispanic, and 81.5%were white. For other patients, the mean age was 66.6 years, 29.1%were women, 11.3%were Hispanic, and 79.1%were white. Incomplete revascularization was very common (78%among patients with STEMI and 71%among other patients). Patients with IR in a vessel with at least 90% stenosis were at higher risk than other patients with IR. This was not significant among patients with STEMI (17.18%vs 12.86%; adjusted hazard ratio [AHR], 1.16; 95%CI, 0.99-1.37) and significant among patients without STEMI (17.71% vs 12.96%; AHR, 1.15; 95%CI, 1.07-1.24). Similarly, patients with IR in 2 or more vessels had higher mortality than patients with completely revascularization and higher mortality than other patients with IR among patients with STEMI (20.37%vs 14.39%; AHR, 1.35; 95%CI, 1.15-1.59) and among patients without STEMI (20.10% vs 12.86%; AHR, 1.17; 95% CI, 1.09-1.59). Patients with proximal left anterior descending artery vessel IR had higher mortality than other patients with IR (20.09% vs 14.67%; AHR, 1.31; 95%CI, 1.04-1.64 for patients with STEMI and 20.78%vs 15.62%; AHR, 1.11; 95%CI, 1.01-1.23 for patients without STEMI). More than 20%of all PCI patients had IR of 2 or more vessels and more than 30% had IR with more than 90% stenosis. CONCLUSIONS AND RELEVANCE Patients with IR are at higher risk of mortality if they have IR with at least 90% stenosis, IR in 2 or more vessels, or proximal left anterior descending IR

Water- and nutrient-dependent effects of dietary restriction on Drosophila lifespan

Dietary restriction (DR) is a widely conserved intervention leading to lifespan extension. Despite considerable effort, the mechanisms underlying DR remain poorly understood. In particular, it remains unclear whether DR prolongs life through conserved mechanisms in different species. Here, we show that, in the most common experimental conditions, lifespan extension by DR is abolished by providing Drosophila with ad libitum water, without altering food intake, indicating that DR, as conventionally studied in flies, is fundamentally different from the phenomenon studied in mammals. We characterize an alternative dietary paradigm that elicits robust lifespan extension irrespective of water availability, and thus likely represents a more relevant model for mammalian DR. Our results support the view that protein:carbohydrate ratio is the main dietary determinant of fly lifespan. These findings have broad implications for the study of lifespan and nutrition

Target and beam-target spin asymmetries in exclusive pion electroproduction for Q2>1GeV2 . I. ep→eπ+n

Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive π + electroproduction reaction γ ∗ p → n π + . The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic range covered is 1.1 < W < 3 GeV and 1 < Q 2 < 6 GeV 2 . Results were obtained for about 6000 bins in W ,   Q 2 ,   cos ( θ ∗ ) , and ϕ ∗ . Except at forward angles, very large target-spin asymmetries are observed over the entire W region. Reasonable agreement is found with phenomenological fits to previous data for W < 1.6 GeV, but very large differences are seen at higher values of W . A generalized parton distributions (GPD)-based model is in poor agreement with the data. When combined with cross-sectional measurements, the present results provide powerful constraints on nucleon resonance amplitudes at moderate and large values of Q 2 , for resonances with masses as high as 2.4 GeV

First Results from The GlueX Experiment

The GlueX experiment at Jefferson Lab ran with its first commissioning beam in late 2014 and the spring of 2015. Data were collected on both plastic and liquid hydrogen targets, and much of the detector has been commissioned. All of the detector systems are now performing at or near design specifications and events are being fully reconstructed, including exclusive production of $\pi^{0}$, $\eta$ and $\omega$ mesons. Linearly-polarized photons were successfully produced through coherent bremsstrahlung and polarization transfer to the $\rho$ has been observed.Comment: 8 pages, 6 figures, Invited contribution to the Hadron 2015 Conference, Newport News VA, September 201

Helicity-dependent cross sections and double-polarization observable E in η photoproduction from quasifree protons and neutrons

Precise helicity-dependent cross sections and the double-polarization observable E were measured for η photoproduction from quasifree protons and neutrons bound in the deuteron. The η → 2γ and η → 3π0 → 6γ decay modes were used to optimize the statistical quality of the data and to estimate systematic uncertainties. The measurement used the A2 detector setup at the tagged photon beam of the electron accelerator MAMI in Mainz. A longitudinally polarized deuterated butanol target was used in combination with a circularly polarized photon beam from bremsstrahlung of a longitudinally polarized electron beam. The reaction products were detected with the electromagnetic calorimeters Crystal Ball and TAPS, which covered 98% of the full solid angle. The results show that the narrow structure observed earlier in the unpolarized excitation function of η photoproduction off the neutron appears only in reactions with antiparallel photon and nucleon spin (σ1/2). It is absent for reactions with parallel spin orientation (σ3/2) and thus very probably related to partial waves with total spin 1/2. The behavior of the angular distributions of the helicity-dependent cross sections was analyzed by fitting them with Legendre polynomials. The results are in good agreement with a model from the Bonn-Gatchina group, which uses an interference of P11 and S11 partial waves to explain the narrow structure

Feasibility studies of the time-like proton electromagnetic form factor measurements with PANDA at FAIR

The possibility of measuring the proton electromagnetic form factors in the time-like region at FAIR with the \PANDA detector is discussed. Detailed simulations on signal efficiency for the annihilation of $\bar p +p$ into a lepton pair as well as for the most important background channels have been performed. It is shown that precision measurements of the differential cross section of the reaction $\bar p +p \to e^++ e^-$ can be obtained in a wide angular and kinematical range. The individual determination of the moduli of the electric and magnetic proton form factors will be possible up to a value of momentum transfer squared of $q^2\simeq 14$ (GeV/c)$^2$. The total $\bar p +p\to e^++e^-$ cross section will be measured up to $q^2\simeq 28$ (GeV/c)$^2$. The results obtained from simulated events are compared to the existing data. Sensitivity to the two photons exchange mechanism is also investigated.Comment: 12 pages, 4 tables, 8 figures Revised, added details on simulations, 4 tables, 9 figure