The Programme for International Students Assessment (PISA) has become one of the most influential forces in global education. The growing influence has been accompanied by growing criticism. For ...nearly two decades since the first round of PISA was conducted in 2000, the global assessment program has been roundly scrutinized and criticized by education researchers all over the world. But the mounting criticism seems to have had little impact on PISA’s influence as evidenced by its growing power in global education policy and practice. The lack of impact of criticism does not mean the criticism is not valid or PISA has improved. It simply means that the criticism has been largely ignored. The lack of impact is no reason to give up exposing PISA as a flawed business that has great power to misguide education. The expanding influence of the PISA enterprise makes it more even more important to be critical of this juggernaut today. It is also important to consider more effective and more straightforward approaches to present the criticism. The purpose of this article is to present a summary of criticisms that reveal the most fundamental flaws of PISA in non-technical language in one place. Specifically, the article focuses on criticisms of PISA’s three fundamental deficiencies: its underlying view of education, its implementation, and its interpretation and impact on education globally.
Feature extraction is of significance for hyperspectral image (HSI) classification. Compared with conventional hand-crafted feature extraction, deep learning can automatically learn features with ...discriminative information. However, two issues exist in applying deep learning to HSIs. One issue is how to jointly extract spectral features and spatial features, and the other one is how to train the deep model when training samples are scarce. In this paper, a deep convolutional neural network with two-branch architecture is proposed to extract the joint spectral-spatial features from HSIs. The two branches of the proposed network are devoted to features from the spectral domain as well as the spatial domain. The learned spectral features and spatial features are then concatenated and fed to fully connected layers to extract the joint spectral-spatial features for classification. When the training samples are limited, we investigate the transfer learning to improve the performance. Low and mid-layers of the network are pretrained and transferred from other data sources; only top layers are trained with limited training samples extracted from the target scene. Experiments on Airborne Visible/Infrared Imaging Spectrometer and Reflective Optics System Imaging Spectrometer data demonstrate that the learned deep joint spectral-spatial features are discriminative, and competitive classification results can be achieved when compared with state-of-the-art methods. The experiments also reveal that the transferred features boost the classification performance.
Electrochemical water splitting to produce hydrogen and oxygen, as an important reaction for renewable energy storage, needs highly efficient and stable catalysts. Herein, FeS2/CoS2 interface ...nanosheets (NSs) as efficient bifunctional electrocatalysts for overall water splitting are reported. The thickness and interface disordered structure with rich defects of FeS2/CoS2 NSs are confirmed by atomic force microscopy and high‐resolution transmission electron microscopy. Furthermore, extended X‐ray absorption fine structure spectroscopy clarifies that FeS2/CoS2 NSs with sulfur vacancies, which can further increase electrocatalytic performance. Benefiting from the interface nanosheets' structure with abundant defects, the FeS2/CoS2 NSs show remarkable hydrogen evolution reaction (HER) performance with a low overpotential of 78.2 mV at 10 mA cm−2 and a superior stability for 80 h in 1.0 m KOH, and an overpotential of 302 mV at 100 mA cm−2 for the oxygen evolution reaction (OER). More importantly, the FeS2/CoS2 NSs display excellent performance for overall water splitting with a voltage of 1.47 V to achieve current density of 10 mA cm−2 and maintain the activity for at least 21 h. The present work highlights the importance of engineering interface nanosheets with rich defects based on transition metal dichalcogenides for boosting the HER and OER performance.
FeS2/CoS2 interface nanosheets with rich defects show excellent electrocatalytic performance for hydrogen evolution reaction and oxygen evolution reaction in alkaline electrolytes. The overall water splitting device built with FeS2/CoS2 nanosheets as both cathode and anode also shows an excellent performance.
Hyperspectral image (HSI) denoising is an essential preprocess step to improve the performance of subsequent applications. For HSI, there is much global and local redundancy and correlation (RAC) in ...spatial/spectral dimensions. In addition, denoising performance can be improved greatly if RAC is utilized efficiently in the denoising process. In this paper, an HSI denoising method is proposed by jointly utilizing the global and local RAC in spatial/spectral domains. First, sparse coding is exploited to model the global RAC in the spatial domain and local RAC in the spectral domain. Noise can be removed by sparse approximated data with learned dictionary. At this stage, only local RAC in the spectral domain is employed. It will cause spectral distortion. To compensate the shortcoming of local spectral RAC, low-rank constraint is used to deal with the global RAC in the spectral domain. Different hyperspectral data sets are used to test the performance of the proposed method. The denoising results by the proposed method are superior to results obtained by other state-of-the-art hyperspectral denoising methods.
The exploration of highly efficient nonprecious metal bifunctional electrocatalysts to boost oxygen evolution reaction and oxygen reduction reaction is critical for development of high energy density ...metal‐air batteries. Herein, a class of CuS/NiS2 interface nanocrystals (INs) catalysts with atomic‐level coupled nanointerface, subtle lattice distortion, and plentiful vacancy defects is reported. The results from temperature‐dependent in situ synchrotron‐based X‐ray absorption fine spectroscopy and electron spin resonance spectroscopy demonstrate that the lattice distortion of 14.7% in CuS/NiS2 caused by the strong Jahn–Teller effect of Cu, the strong atomic‐level coupled interface of CuS and NiS2 domains, and distinct vacancy defects can provide numerous effective active sites for their excellent bifunctional performance. A liquid Zn‐air battery with the CuS/NiS2 INs as air electrode displays a large peak power density (172.4 mW cm−2), a high specific capacity (775 mAh gZn−1), and long cycle life (up to 83 h), making the CuS/NiS2 INs among the best bifunctional catalysts for Zn‐air battery. More remarkably, the flexible CuS/NiS2 INs‐based solid‐state Zn‐air batteries can power the LED after twisting, making them be promising in portable and wearable electronic devices.
The anomalous CuS/NiS2 interface nanocrystals (INs) with nanointerfaces, subtle lattice distortion with a degree of about 14.7%, and rich defects show excellent electrocatalytic performance for both oxygen evolution reaction and reduction reaction. A Zn‐air battery with CuS/NiS2 INs as air‐cathode demonstrates high performance, even after bending with various shapes. Flexible CuS/NiS2 INs‐based solid‐state Zn‐air batteries can even power light‐emitting diodes.
Lanthanide metal–organic frameworks (Ln‐MOFs) have received much attention owing to their structural tunability and widely photofunctional applications. However, successful examples of Ln‐MOFs with ...well‐defined photonic performances at micro‐/nanometer size are still quite limited. Herein, self‐assemblies of 1,3,5‐benzenetricarboxylic acid (BTC) and lanthanide ions afford isostructural crystalline Ln‐MOFs. Tb‐BTC, Eu@Tb‐BTC, and Eu‐BTC have 1D microrod morphologies, high photoluminescence (PL) quantum yields, and different emission colors (green, orange, and red). Spatially PL resolved spectra confirm that Ln‐MOF microrods exhibit an optical waveguide effect with low waveguide loss coefficient (0.012≈0.033 dB μm−1) during propagation. Furthermore, these microrods feature both linear and chiral polarized photoemission with high anisotropy.
Lightsabers: Three crystalline isostructural lanthanide metal–organic frameworks (Ln‐MOFs) with 1D microrod morphologies, high photoluminescence quantum yields, and different emission colors are prepared. The Ln‐MOFs feature low waveguide loss as well as high linear‐ and chiral‐polarization anisotropy.
Hyperspectral image super-resolution by fusing high-resolution multispectral image (HR-MSI) and low-resolution hyperspectral image (LR-HSI) aims at reconstructing high resolution spatial-spectral ...information of the scene. Existing methods mostly based on spectral unmixing and sparse representation are often developed from a low-level vision task perspective, they cannot sufficiently make use of the spatial and spectral priors available from higher-level analysis. To this issue, this paper proposes a novel HSI super-resolution method that fully considers the spatial/spectral subspace low-rank relationships between available HR-MSI/LR-HSI and latent HSI. Specifically, it relies on a new subspace clustering method named "structured sparse low-rank representation" (SSLRR), to represent the data samples as linear combinations of the bases in a given dictionary, where the sparse structure is induced by low-rank factorization for the affinity matrix. Then we exploit the proposed SSLRR model to learn the SSLRR along spatial/spectral domain from the MSI/HSI inputs. By using the learned spatial and spectral low-rank structures, we formulate the proposed HSI super-resolution model as a variational optimization problem, which can be readily solved by the ADMM algorithm. Compared with state-of-the-art hyperspectral super-resolution methods, the proposed method shows better performance on three benchmark datasets in terms of both visual and quantitative evaluation.
Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer featured with high intra-tumoral heterogeneity and poor prognosis. To comprehensively delineate the PDAC ...intra-tumoral heterogeneity and the underlying mechanism for PDAC progression, we employed single-cell RNA-seq (scRNA-seq) to acquire the transcriptomic atlas of 57,530 individual pancreatic cells from primary PDAC tumors and control pancreases, and identified diverse malignant and stromal cell types, including two ductal subtypes with abnormal and malignant gene expression profiles respectively, in PDAC. We found that the heterogenous malignant subtype was composed of several subpopulations with differential proliferative and migratory potentials. Cell trajectory analysis revealed that components of multiple tumor-related pathways and transcription factors (TFs) were differentially expressed along PDAC progression. Furthermore, we found a subset of ductal cells with unique proliferative features were associated with an inactivation state in tumor-infiltrating T cells, providing novel markers for the prediction of antitumor immune response. Together, our findings provide a valuable resource for deciphering the intra-tumoral heterogeneity in PDAC and uncover a connection between tumor intrinsic transcriptional state and T cell activation, suggesting potential biomarkers for anticancer treatment such as targeted therapy and immunotherapy.
Light‐emitting diodes (LEDs) in a tandem configuration offer a strategy to realize high‐performance, multicolor devices. Until now, though, the efficiency of tandem colloidal quantum dot LEDs (QLEDs) ...has been limited due to unpassivated interfaces and solvent damage originating from the materials processing requirements of interconnecting layers (ICLs). Here an ICL is reported consisting of a semiconductor‐metal‐dielectric stack that provides facile fabrication, materials stability, and good optoelectronic coupling. It is investigated experimentally how the ICL enables charge balance, suppresses current leakage, and prevents solvent damage to the underlying layers. As a result record efficiencies are reported for double‐junction tandem QLEDs, whose emission wavelengths cover from blue to red light; i.e., external quantum efficiencies (EQEs) of 40% (average 37+/−2%) for red, 49% (average 45+/−2%) for yellow, 50% (average 46+/−2%) for green, and 24% (average 21+/−2%) for blue are achieved.
A highly efficient interconnecting layers (ICLs) are reported consisting of multifunctional inorganic semiconductor‐metal‐dielectric stack, which enables the resultant tandem quantum dot light emitting diodes (QLEDs) with double junction to achieve a record efficiency, with the EQEs of 40% for red, 49% for yellow, 50% for green, and 24% for blue.
Over 17 and 160 types of chemical modifications have been identified in DNA and RNA, respectively. The interest in understanding the various biological functions of DNA and RNA modifications has lead ...to the cutting-edged fields of epigenomics and epitranscriptomics. Developing chemical and biological tools to detect specific modifications in the genome or transcriptome has greatly facilitated their study. Here, we review the recent technological advances in this rapidly evolving field. We focus on high-throughput detection methods and biological findings for these modifications, and discuss questions to be addressed as well. We also summarize third-generation sequencing methods, which enable long-read and single-molecule sequencing of DNA and RNA modification.
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