17,661 research outputs found
Calculation of subsonic and supersonic steady and unsteady aerodynamic forces using velocity potential aerodynamic elements
Expressions for calculation of subsonic and supersonic, steady and unsteady aerodynamic forces are derived, using the concept of aerodynamic elements applied to the downwash velocity potential method. Aerodynamic elements can be of arbitrary out of plane polygon shape, although numerical calculations are restricted to rectangular elements, and to the steady state case in the supersonic examples. It is suggested that the use of conforming, in place of rectangular elements, would give better results. Agreement with results for subsonic oscillating T tails is fair, but results do not converge as the number of collocation points is increased. This appears to be due to the form of expression used in the calculations. The methods derived are expected to facilitate automated flutter analysis on the computer. In particular, the aerodynamic element concept is consistent with finite element methods already used for structural analysis. The method is universal for the complete Mach number range, and, finally, the calculations can be arranged so that they do not have to be repeated completely for every reduced frequency
Policies And International Integration: Influences On Trade And Foreign Direct Investment
This paper assesses the importance of border and non-border policies for global economic integration. The focus is on four widely-advocated policies: removing explicit restrictions to trade and FDI; promoting domestic competition; improving the adaptability of labour markets; and ensuring adequate levels of infrastructure capital. The analysis covers FDI and trade in both goods and services, thus aiming to account for the most important channels of globalisation and dealing with most modes of cross-border services supply. It first describes trends in trade, FDI and the four sets of policies using a large set of structural policy indicators recently constructed by the OECD, including the new summary indicators for FDI-specific regulations described in Golub (2003). It then estimates the impact of policies on bilateral trade and bilateral and multilateral FDI. The results highlight that, despite extensive liberalisation over the past two decades, there is scope for further reducing policy barriers to integration of OECD markets. Remaining barriers have a significant impact on trade and FDI, with anticompetitive domestic regulations and restrictive labour market arrangements estimated to curb integration as much as explicit trade and FDI restrictions. Simulating the removal of such barriers suggests that the quantitative effects of further liberalisation of trade, FDI and domestic product and labour markets on global integration could be substantial
A computationally efficient inorganic atmospheric aerosol phase equilibrium model (UHAERO)
A variety of thermodynamic models have been developed to predict inorganic gas-aerosol equilibrium. To achieve computational efficiency a number of the models rely on a priori specification of the phases present in certain relative humidity regimes. Presented here is a new computational model, named UHAERO, that is both efficient and rigorously computes phase behavior without any a priori specification. The computational implementation is based on minimization of the Gibbs free energy using a primal-dual method, coupled to a Newton iteration. The mathematical details of the solution are given elsewhere. The model also computes deliquescence and crystallization behavior without any a priori specification of the relative humidities of deliquescence or crystallization. Detailed phase diagrams of the sulfate/nitrate/ammonium/water system are presented as a function of relative humidity at 298.15 K over the complete space of composition
A new inorganic atmospheric aerosol phase equilibrium model (UHAERO)
A variety of thermodynamic models have been developed to predict inorganic gas-aerosol equilibrium. To achieve computational efficiency a number of the models rely on a priori specification of the phases present in certain relative humidity regimes. Presented here is a new computational model, named UHAERO, that is both efficient and rigorously computes phase behavior without any a priori specification. The computational implementation is based on minimization of the Gibbs free energy using a primal-dual method, coupled to a Newton iteration. The mathematical details of the solution are given elsewhere. The model computes deliquescence behavior without any a priori specification of the relative humidities of deliquescence. Also included in the model is a formulation based on classical theory of nucleation kinetics that predicts crystallization behavior. Detailed phase diagrams of the sulfate/nitrate/ammonium/water system are presented as a function of relative humidity at 298.15 K over the complete space of composition
Unsupervised Holistic Image Generation from Key Local Patches
We introduce a new problem of generating an image based on a small number of
key local patches without any geometric prior. In this work, key local patches
are defined as informative regions of the target object or scene. This is a
challenging problem since it requires generating realistic images and
predicting locations of parts at the same time. We construct adversarial
networks to tackle this problem. A generator network generates a fake image as
well as a mask based on the encoder-decoder framework. On the other hand, a
discriminator network aims to detect fake images. The network is trained with
three losses to consider spatial, appearance, and adversarial information. The
spatial loss determines whether the locations of predicted parts are correct.
Input patches are restored in the output image without much modification due to
the appearance loss. The adversarial loss ensures output images are realistic.
The proposed network is trained without supervisory signals since no labels of
key parts are required. Experimental results on six datasets demonstrate that
the proposed algorithm performs favorably on challenging objects and scenes.Comment: 16 page
Social media use and impact during the holiday travel planning process
Through an empirical study among holiday travellers, residing in the Former Soviet Union Republics, this paper presents a comprehensive view of role and impact of social media on the whole holiday travel planning process: Before, during and after the trip, providing insights on usage levels, scope of use, level of influence and trust. Findings suggest that social media are predominantly used after holidays for experience sharing. It is also shown that there is a strong correlation between perceived level of influence from social media and changes made in holiday plans prior to final decisions. Moreover, it is revealed that user-generated content is perceived as more trustworthy when compared to official tourism websites, travel agents and mass media advertising
The Mre11-Rad50-Nbs1 complex mediates activation of TopBP1 by ATM
The activation of ATR-ATRIP in response to double-stranded DNA breaks (DSBs) depends upon ATM in human cells and Xenopus egg extracts. One important aspect of this dependency involves regulation of TopBP1 by ATM. In Xenopus egg extracts, ATM associates with TopBP1 and thereupon phosphorylates it on S1131. This phosphorylation enhances the capacity of TopBP1 to activate the ATR-ATRIP complex. We show that TopBP1 also interacts with the Mre11-Rad50-Nbs1 (MRN) complex in egg extracts in a checkpoint-regulated manner. This interaction involves the Nbs1 subunit of the complex. ATM can no longer interact with TopBP1 in Nbs1-depleted egg extracts, which suggests that the MRN complex helps to bridge ATM and TopBP1 together. The association between TopBP1 and Nbs1 involves the first pair of BRCT repeats in TopBP1. In addition, the two tandem BRCT repeats of Nbs1 are required for this binding. Functional studies with mutated forms of TopBP1 and Nbs1 suggested that the BRCT-dependent association of these proteins is critical for a normal checkpoint response to DSBs. These findings suggest that the MRN complex is a crucial mediator in the process whereby ATM promotes the TopBP1-dependent activation of ATR-ATRIP in response to DSBs
Pathogenicity of the H1N1 influenza virus enhanced by functional synergy between the NPV100I and NAD248N pair
By comparing and measuring covariations of viral protein sequences from isolates of the 2009 pH1N1 influenza A virus (IAV), specific substitutions that co-occur in the NP-NA pair were identified. To investigate the effect of these co-occurring substitution pairs, the V100I substitution in NP and the D248N substitution in NA were introduced into laboratory-adapted WSN IAVs. The recombinant WSN with the covarying NPV100I-NAD248N pair exhibited enhanced pathogenicity, as characterized by increased viral production, increased death and inflammation of host cells, and high mortality in infected mice. Although direct interactions between the NPV100I and NAD248N proteins were not detected, the RNA-binding ability of NPV100I was increased, which was further strengthened by NAD248N, in expression-plasmid- transfected cells. Additionally, the NAD248N protein was frequently recruited within lipid rafts, indirectly affecting the RNA-binding ability of NP as well as viral release. Altogether, our data indicate that the covarying NPV100I-NAD248N pair obtained from 2009 pH1N1 IAV sequence information function together to synergistically augment viral assembly and release, which may explain the observed enhanced viral pathogenicity. © 2019 Kim et al.11Ysciescopu
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