The HSS iteration method is effective to solve non-Hermitian positive definite linear systems, but the choice of its optimal parameter is a difficult and challenging problem in theoretical analysis ...and practical computations. In this paper, we obtain an accurate estimate to the optimal parameter of the HSS iteration method by adopting a reasonable and simple optimization principle. Numerical experiments show that this principle is feasible to produce an accurate estimate to the optimal parameter of the HSS iteration method.
Nitrogen (N), potassium (K), and phosphorus (P) are essential macronutrients for plant growth and development, and their availability affects crop yield. Compared with N, the relatively low ...availability of K and P in soils limits crop production and thus threatens food security and agricultural sustainability. Improvement of plant nutrient utilization efficiency provides a potential route to overcome the effects of K and P deficiencies. Investigation of the molecular mechanisms underlying how plants sense, absorb, transport, and use K and P is an important prerequisite to improve crop nutrient utilization efficiency. In this review, we summarize current understanding of K and P transport and signaling in plants, mainly taking Arabidopsis thaliana and rice (Oryza sativa) as examples. We also discuss the mechanisms coordinating transport of N and K, as well as P and N.
Potassium (K) and phosphorus (P) are essential macronutrients for plant growth, development, and crop yield. This review summarizes the current understanding of K and P transport and signaling in plants and discusses the mechanisms coordinating N (nitrogen), K, and P.
Human infection with the novel avian-origin influenza A (H7N9) virus has aroused global concern. In this report, the clinical characteristics of 111 laboratory-confirmed cases in China are presented.
...On March 30, 2013, three patients with fatal cases of rapid, progressive pneumonia were confirmed to be infected with a novel avian-origin influenza A (H7N9) virus that had not been detected in humans and animals previously.
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The new human H7N9 viruses are the product of reassortment of viruses that are of avian origin.
Global attention was soon focused on the situation because of the increasing number of new cases and the high rate of death associated with these infections.
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As of May 9, the World Health Organization (WHO) had reported 131 laboratory-confirmed cases, including 32 deaths.
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However, data on . . .
Deep learning-based methods have achieved remarkable success in image restoration and enhancement, but are they still competitive when there is a lack of paired training data? As one such example, ...this paper explores the low-light image enhancement problem, where in practice it is extremely challenging to simultaneously take a low-light and a normal-light photo of the same visual scene. We propose a highly effective unsupervised generative adversarial network, dubbed EnlightenGAN , that can be trained without low/normal-light image pairs, yet proves to generalize very well on various real-world test images. Instead of supervising the learning using ground truth data, we propose to regularize the unpaired training using the information extracted from the input itself, and benchmark a series of innovations for the low-light image enhancement problem, including a global-local discriminator structure, a self-regularized perceptual loss fusion, and the attention mechanism. Through extensive experiments, our proposed approach outperforms recent methods under a variety of metrics in terms of visual quality and subjective user study. Thanks to the great flexibility brought by unpaired training, EnlightenGAN is demonstrated to be easily adaptable to enhancing real-world images from various domains. Our codes and pre-trained models are available at: https://github.com/VITA-Group/EnlightenGAN .
This study sought to elucidate the antecedents that may influence the effect of people's purchase behavior on the Earth's sustainable development. It included people's perceived moral obligation and ...sustainability self‐identity in the theory of planned behavior (TPB) model to investigate attitudes among the Taiwanese public's attitude toward purchasing sustainability‐labeled coffee and their purchase intentions. The moderating effect of climate change skepticism is also considered in this study. A total of 745 nationwide and self‐reported questionnaire valid data was collected in Taiwan. Hierarchical and moderated regression analysis results indicated that the components of the TPB model had positive influences on the public's purchase intention. The public's perceived moral obligation and sustainability self‐identity, proposed for inclusion in the TPB model, had significant and positive influences on purchase intention. The extended TPB model has higher explanatory power than that of the original model. The positive relationship between sustainability self‐identity and intention to purchase sustainability‐labeled coffee was moderated by climate change skepticism. This study provides marketers and the players in the supply chain with a comprehensive framework for understanding the influence of perceived moral obligation and sustainability self‐identity on purchase intention toward sustainability‐labeled products. In addition, this study responds to a call for a more thorough investigation of the effect of people's skepticism about climate change in the context of ethical and sustainable consumption decision‐making processes.
In this work, we propose a new solution to 3D human pose estimation in videos. Instead of directly regressing the 3D joint locations, we draw inspiration from the human skeleton anatomy and decompose ...the task into bone direction prediction and bone length prediction, from which the 3D joint locations can be completely derived. Our motivation is the fact that the bone lengths of a human skeleton remain consistent across time. This promotes us to develop effective techniques to utilize global information across all the frames in a video for high-accuracy bone length prediction. Moreover, for the bone direction prediction network, we propose a fully-convolutional propagating architecture with long skip connections. Essentially, it predicts the directions of different bones hierarchically without using any time-consuming memory units ( e.g. LSTM). A novel joint shift loss is further introduced to bridge the training of the bone length and bone direction prediction networks. Finally, we employ an implicit attention mechanism to feed the 2D keypoint visibility scores into the model as extra guidance, which significantly mitigates the depth ambiguity in many challenging poses. Our full model outperforms the previous best results on Human3.6M and MPI-INF-3DHP datasets, where comprehensive evaluation validates the effectiveness of our model.
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bstract
At the heart of recent progress in AdS/CFT is the question of subregion duality, or entanglement wedge reconstruction: which part(s) of the boundary CFT are dual to a given subregion of the ...bulk? This question can be answered by appealing to the quantum error correcting properties of holography, and it was recently shown that robust bulk (entanglement wedge) reconstruction can be achieved using a universal recovery channel known as the
twirled Petz map
. In short, one can use the twirled Petz map to recover bulk data from a subset of the boundary. However, this map involves an averaging procedure over bulk and boundary modular time, and hence it can be somewhat intractable to evaluate in practice. We show that a much simpler channel, the Petz map, is sufficient for entanglement wedge reconstruction for any code space of fixed finite dimension — no twirling is required. Moreover, the error in the reconstruction will always be non-perturbatively small. From a quantum information perspective, we prove a general theorem extending the use of the Petz map as a general-purpose recovery channel to subsystem and operator algebra quantum error correction.
This article reviews the progress made in emerging photovoltaic devices, including dye‐sensitized solar cells, organic solar cells, and perovskite solar cells, for specialty applications. Because ...they all feature tunable band structures, which can be modified through molecular design and/or altered compositions, the properties of emerging photovoltaic devices can be tailored to fit the special requirements of a particular application. For instance, they can be designed according to the emission spectrum of an artificial light source (e.g., fluorescence lamp and white light‐emitting diode), thereby efficiently converting the indoor lighting to electricity. Furthermore, because there exists a near‐infrared window—ranging from 650 to 1350 nm—in which photons can penetrate deeply into tissues, the absorption bands of these photovoltaic devices can be tailored specially to this therapeutic window to harvest tissue‐penetrating light, thereby wirelessly providing power to biomedical devices positioned beneath the skin. The rapid progress made in these two representative areas suggests further promising applications of such emerging photovoltaic devices.
Emerging organic and organic/inorganic hybrid photovoltaic devices, including dye‐sensitized solar cells, organic solar cells, and perovskite solar cells, feature tunable band structures that can be modified through molecular designs and/or altering their compositions. The rapid progress of their use in two specialty areas—indoor light energy recycling and powering biomedical devices beneath the skin—is reviewed.
Based on first-principle calculations, we show that a family of nonmagnetic materials including TaAs, TaP, NbAs, and NbP are Weyl semimetals (WSM) without inversion centers. We find twelve pairs of ...Weyl points in the whole Brillouin zone (BZ) for each of them. In the absence of spin-orbit coupling (SOC), band inversions in mirror-invariant planes lead to gapless nodal rings in the energy-momentum dispersion. The strong SOC in these materials then opens full gaps in the mirror planes, generating nonzero mirror Chern numbers and Weyl points off the mirror planes. The resulting surface-state Fermi arc structures on both (001) and (100) surfaces are also obtained, and they show interesting shapes, pointing to fascinating playgrounds for future experimental studies.
Regiella insecticola is a bacterial endosymbiont in insects that exhibits a negative effect on the fitness of hosts. Thus, it is not clear why this costly endosymbiont can persist in host ...populations. Here, we tested a hypothesis that the infection pattern and negative roles of the endosymbiont were not constant but environmentally dependent. The grain aphids Sitobion avenae, belonging to different genotypes and infected with Regiella or not, were used in this study. We found that S. avenae populations were infected with Regiella, Hamiltonella defensa, Serratia symbiotica and Rickettsia. The predominant endosymbionts in the aphid populations varied with season. Serratia and Rickettsia were predominant from December to February while Regiella predominated from March to May. The vertical transmission of Regiella was poorer at high temperature, but following conditioning for seven generations, the transmission rate improved. Regiella inhibited the production of winged aphids at 25 °C, but it did not affect winged morph production at the higher temperatures of 28 °C and 31 °C. Regiella infection decreased the intrinsic rate of increase (r
) of aphids at 25 °C and 28 °C. However, at 31 °C, the effect of Regiella on the r
varied depending on the aphid genotype and density. Thus, the negative effects of this endosymbiont on its host were environmentally dependent.
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