Structural design of a vertical antenna boresight 18.3 by 18.3-m planar near-field antenna measurement system

A large very precise near-field planar scanner was proposed for NASA Lewis Research Center. This scanner would permit near-field measurements over a horizontal scan plane measuring 18.3 m by 18.3 m. Large aperture antennas mounted with antenna boresight vertical could be tested up to 60 GHz. When such a large near field scanner is used for pattern testing, the antenna or antenna system under test does not have to be moved. Hence, such antennas and antenna systems can be positioned and supported to simulate configuration in zero g. Thus, very large and heavy machinery that would be needed to accurately move the antennas are avoided. A preliminary investigation was undertaken to address the mechanical design of such a challenging near-field antenna scanner. The configuration, structural design and results of a parametric NASTRAN structural optimization analysis are contained. Further, the resulting design was dynamically analyzed in order to provide resonant frequency information to the scanner mechanical drive system designers. If other large near field scanners of comparable dimensions are to be constructed, the information can be used for design optimization of these also

International business relationships triads: Classical-type and relational-type interactions between Chinese and western firms

China’s expanding position within the global business arena has placed focus on its role in assisting to stimulate the global economy during the current ‘global financial crisis’. This raises the importance of better understanding how the Chinese conduct their inter-firm interactions, in their exchanges between Chinese and Western firms. We report an expository study that identifies both classical-type exchange and interactions that are relational-type in the one context and how these conflate to form triadic structures within business networks. From case study evidence, we propose a typology of triadic interorganisational forms. To understand better exchange in this complex international marketing context, and the additional demands this places on relationships management, it is important that we understand the causes and nature of the fuzziness of these opaque inter-firm network structures

Trade protection along supply chains

During the last decades, the United States has applied increasingly high trade protection against China. We combine detailed information on US antidumping (AD) duties— the most widely used trade barrier — with US input-output data to study the effects of trade protection along supply chains. To deal with endogeneity concerns, we propose a new instrument for AD protection, which combines exogenous variation in the political importance of industries with their historical experience in AD proceedings. We find that tariffs have large negative effects on downstream industries, decreasing employment, wages, sales, and investment. Our baseline estimates for 1988-2016 indicate that, due to AD protection against China, around 1.8 million US jobs were lost in downstream industries, with no significant job gains in protected sectors. When we extend the analysis to measures introduced under President Trump, we find that around 500,000 jobs were lost during the first two years of his term. We also provide evidence of the mechanisms behind the negative effects of protection along supply chains: AD duties decrease imports and raise production costs for downstream industries

Trade protection along supply chains: how antidumping measures against China hurt downstream industries

Production processes are often no longer confined to a single country; supply chains can be fragmented across great distances. By contrast, tariffs are often used by individual countries to protect certain industries. In new research, which studies the effects of US antidumping duties applied against China, Chad P. Bown, Paola Conconi, Aksel Erbahar and Lorenzo Trimarchi find that these protectionist [...

Multi-component Transparent Conducting Oxides: Progress in Materials Modelling

Transparent conducting oxides (TCOs) play an essential role in modern optoelectronic devices through their combination of electrical conductivity and optical transparency. We review recent progress in our understanding of multi-component TCOs formed from solid-solutions of ZnO, In2O3, Ga2O3 and Al2O3, with a particular emphasis on the contributions of materials modelling, primarily based on Density Functional Theory. In particular, we highlight three major results from our work: (i) the fundamental principles governing the crystal structures of multi-component oxide structures including (In2O3)(ZnO)n, named IZO, and (In2O3)m(Ga2O3)l(ZnO)n, named IGZO; (ii) the relationship between elemental composition and optical and electrical behaviour, including valence band alignments; (iii) the high-performance of amorphous oxide semiconductors. From these advances, the challenge of the rational design of novel electroceramic materials is discussed.Comment: Part of a themed issue of Journal of Physics: Condensed Matter on "Semiconducting Oxides". In Press (2011

The transcriptome of retinal Müller glial cells

Müller glial cells are the major type of glia in the mammalian retina. To identify the molecular machinery that defines Müller glial cell identity and function, single cell gene expression profiling was performed on Affymetrix microarrays. Identification of a cluster of genes expressed at high levels suggests a Müller glia core transcriptome, which likely underlies many of the functions of Müller glia. Expression of components of the cell cycle machinery and the Notch pathway, as well as of growth factors, chemokines, and lipoproteins might allow communication between Müller glial cells and the neurons that they support, including modulation of neuronal activity. This approach revealed a set of transcripts that were not previously characterized in (Müller) glia; validation of the expression of some of these genes was performed by in situ hybridization. Genes expressed exclusively by Müller glia were identified as novel markers. In addition, a novel BAC transgenic mouse that expresses Cre in Müller glia cells was generated. The molecular fingerprint of Müller glia provides a foundation for further studies of Müller glia development and function in normal and diseased states

Thoracic Endovascular Aortic Repair for Type B Acute Aortic Dissection Complicated by Descending Thoracic Aneurysm

OBJECTIVES: To analyse the results and review the literature about thoracic aortic endovascular repair (TEVAR) for type B acute aortic dissection (TBAAD) complicated by descending thoracic aortic aneurysm (DTA) in the hyperacute or acute phases. METHODS: This was a multicentre, observational descriptive study. Inclusion criteria were TBAAD with a DTA of 6550 mm, TBAAD on an already known aneurysmal descending thoracic aorta, and TBAAD presenting with an enlarged aorta with a total diameter <50 mm, but with >50% diameter increase compared with a previous computed tomography angiography (CTA) showing a non-dissected aorta with normal sizing. Primary endpoints were early and long-term survival, freedom from TEVAR and aortic related mortality (ARM), and freedom from re-intervention. RESULTS: Twenty-two patients were included in the analysis. The mean aortic diameter was 66 \ub1 26 mm (range 42-130; IQR 51-64). The in hospital TEVAR related mortality was 14% (n = 3). The mean radiological follow-up was 56 \ub1 45 months (range 6-149; IQR 12-82), and the follow-up index 0.97 \ub1 0.1. All surviving patients were available for follow-up. During follow-up the cumulative mortality was 26% (n = 5) and TEVAR related mortality was 5% (n = 1). Overall the estimate of survival was 82% (95%CI: 61.5-93) at 1 year, and 64% at 5 years. Ongoing primary clinical success was 79% (re-intervention n = 4). Freedom from aortic related mortality was 86% (95%CI: 66-95) at 1 and 5 year, while freedom from re-intervention was 95% (95%CI: 75.5-95) at 1 year, and 77% (95%CI: 50-92) at 5 years. CONCLUSIONS: In our experience, DTA is a frequent complication from the very beginning of the clinical onset of TBAAD. In this high-risk cohort, TEVAR showed satisfactory results, better than those predicted by the risk score for open repair, with favourable stability of the aortic diameter and no aortic related adverse events during follow-up

Correlations between isospin dynamics and Intermediate Mass Fragments emission time scales: a probe for the symmetry energy in asymmetric nuclear matter

We show new data from the $^{64}$Ni+$^{124}$Sn and $^{58}$Ni+$^{112}$Sn reactions studied in direct kinematics with the CHIMERA detector at INFN-LNS and compared with the reverse kinematics reactions at the same incident beam energy (35 A MeV). Analyzing the data with the method of relative velocity correlations, fragments coming from statistical decay of an excited projectile-like (PLF) or target-like (TLF) fragments are discriminated from the ones coming from dynamical emission in the early stages of the reaction. By comparing data of the reverse kinematics experiment with a stochastic mean field (SMF) + GEMINI calculations our results show that observables from neck fragmentation mechanism add valuable constraints on the density dependence of symmetry energy. An indication is found for a moderately stiff symmetry energy potential term of EOS.Comment: Talk given by E. De Filippo at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS