Severe distortion in the representation of foveal visual image locations in short term memory

The foveal visual image region provides the human visual system with the highest acuity. However, it is unclear whether such a high fidelity representational advantage is maintained when foveal image locations are committed to short term memory. Here we describe a paradoxically large distortion in foveal target location recall by humans. We briefly presented small, but high contrast, points of light at eccentricities ranging from 0.1 to 12 deg, while subjects maintained their line of sight on a stable target. After a brief memory period, the subjects indicated the remembered target locations via computer controlled cursors. The biggest localization errors, in terms of both directional deviations and amplitude percentage overshoots or undershoots, occurred for the most foveal targets, and such distortions were still present, albeit with qualitatively different patterns, when subjects shifted their gaze to indicate the remembered target locations. Foveal visual images are severely distorted in short term memory.

An Enhanced Half-Quasi-Z-Source Inverter for Wind Energy Conversion System with D-PMSG

To solve the problem of the traditional quasi-Z-source inverters with low voltage gain, an enhanced half-quasi-Z-source inverter (E-HQZSI) is proposed and applied to direct-drive permanent-magnet wind power generation systems in this paper. The expression of the boosting factor is deduced, which shows that E-HQZSI has higher voltage gain compared with the QZSI and HQZSI. However, the higher voltage gain of the E-HQZSI will lead to the large distortion of the generator stator current necessarily. In this paper, a periodic shoot-through duty ratio control scheme is proposed to reduce the stator current harmonics for E-HQZSI. According to the change rule of the single-phase stator current, the shoot-through duty ratio is compromised to make that the three-phase stator currents are as close as possible to the sine wave. Finally, the correctness of the theoretical analysis is verified by simulation and experiment.

The Economy-Wide Impact of Subsidy Reform: A CGE Analysis

Oil prices fell from around $US110 per barrel in 2014 to less than $US50per barrel at the start of 2017. This put enormous pressure on government budgets within the Gulf Cooperation Council (GCC) region. The focus of GCC economic policies quickly shifted to fiscal reform, including the removal of domestic subsidies on energy products. In this paper, we use a dynamic Computable General Equilibrium (CGE) model to investigate the economic impact of the gradual removal of subsidies on refined petroleum and electricity, with specific reference to the Kingdom of Saudi Arabia (KSA).Our study shows that removing subsidies eliminates a large distortion in the economy. This improves the efficiency of resource use, so that even though employment and capital in most years fall relative to baseline levels, real GDP rises. In addition, we show that fully-funded compensation payments offset the increases in energy prices, leaving economic welfare of the Saudi-national population little affected. Removing the energy subsidies leads to an improvement in the net volume of trade, while leading to a mixed outcome for industries.

A Frank-Wolfe Framework for Efficient and Effective Adversarial Attacks

Depending on how much information an adversary can access to, adversarial attacks can be classified as white-box attack and black-box attack. For white-box attack, optimization-based attack algorithms such as projected gradient descent (PGD) can achieve relatively high attack success rates within moderate iterates. However, they tend to generate adversarial examples near or upon the boundary of the perturbation set, resulting in large distortion. Furthermore, their corresponding black-box attack algorithms also suffer from high query complexities, thereby limiting their practical usefulness. In this paper, we focus on the problem of developing efficient and effective optimization-based adversarial attack algorithms. In particular, we propose a novel adversarial attack framework for both white-box and black-box settings based on a variant of Frank-Wolfe algorithm. We show in theory that the proposed attack algorithms are efficient with an O(1/√T) convergence rate. The empirical results of attacking the ImageNet and MNIST datasets also verify the efficiency and effectiveness of the proposed algorithms. More specifically, our proposed algorithms attain the best attack performances in both white-box and black-box attacks among all baselines, and are more time and query efficient than the state-of-the-art.

Case Report: Xanthogranulomatous salpingo-oophoritis associated to endometriosis – are these different histologic expressions of the same disease?

Xanthogranulomatous inflammation is characterized by the presence of foamy histiocytes associated with other inflammatory cells like lymphocytes, plasma cells and neutrophils. It is a rare inflammatory process, which has been more frequently described in chronic pyelonephritis and cholecystitis. Xanthogranulomatosis usually triggers a large distortion of the affected organ, which is secondary to the severe inflammatory response that characterizes this type of lesion. Only a few cases of xanthogranulomatous salpingo-oophoritis have been published to date. Here, we report the case of a xanthogranulomatous salpingo-oophoritis in a patient with endometriosis, suffering from chronic pelvic pain and long-standing infertility. The association between endometriosis and xanthogranulomatous inflammation is extremely rare and can possibly represent a severe histologic expression of this common disorder.