R2DE: a NLP approach to estimating IRT parameters of newly generated questions

The main objective of exams consists in performing an assessment of students' expertise on a specific subject. Such expertise, also referred to as skill or knowledge level, can then be leveraged in different ways (e.g., to assign a grade to the students, to understand whether a student might need some support, etc.). Similarly, the questions appearing in the exams have to be assessed in some way before being used to evaluate students. Standard approaches to questions' assessment are either subjective (e.g., assessment by human experts) or introduce a long delay in the process of question generation (e.g., pretesting with real students). In this work we introduce R2DE (which is a Regressor for Difficulty and Discrimination Estimation), a model capable of assessing newly generated multiple-choice questions by looking at the text of the question and the text of the possible choices. In particular, it can estimate the difficulty and the discrimination of each question, as they are defined in Item Response Theory. We also present the results of extensive experiments we carried out on a real world large scale dataset coming from an e-learning platform, showing that our model can be used to perform an initial assessment of newly created questions and ease some of the problems that arise in question generation

The Role of Sleep Deprivation in Arrhythmias

Sleep is essential to the normal psychological and physiological activities of the human body. Increasing evidence indicates that sleep deprivation is associated with the occurrence, development, and poor treatment effects of various arrhythmias. Sleep deprivation affects not only the peripheral nervous system but also the central nervous system, which regulates the occurrence of arrhythmias. In addition, sleep deprivation is associated with apoptotic pathways, mitochondrial energy metabolism disorders, and immune system dysfunction. Although studies increasingly suggest that pathological sleep patterns are associated with various atrial and ventricular arrhythmias, further research is needed to identify specific mechanisms and recommend therapeutic interventions. This review summarizes the findings of sleep deprivation in animal experiments and clinical studies, current challenges, and future research directions in the field of arrhythmias

A Novel Color Image Encryption Algorithm Using Coupled Map Lattice with Polymorphic Mapping

Some typical security algorithms such as SHA, MD4, MD5, etc. have been cracked in recent years. However, these algorithms have some shortcomings. Therefore, the traditional one-dimensional-mapping coupled lattice is improved by using the idea of polymorphism in this paper, and a polymorphic mapping–coupled map lattice with information entropy is developed for encrypting color images. Firstly, we extend a diffusion matrix with the original 4 × 4 matrix into an n × n matrix. Then, the Huffman idea is employed to propose a new pixel-level substitution method, which is applied to replace the grey degree value. We employ the idea of polymorphism and select f(x) in the spatiotemporal chaotic system. The pseudo-random sequence is more diversified and the sequence is homogenized. Finally, three plaintext color images of 256×256×3, “Lena”, “Peppers” and “Mandrill”, are selected in order to prove the effectiveness of the proposed algorithm. The experimental results show that the proposed algorithm has a large key space, better sensitivity to keys and plaintext images, and a better encryption effect

recentadvancesonthereductionofco2toimportantc2oxygenatedchemicalsandfuels

The chemical utilization of CO2 is a crucial step for the recycling of carbon resource. In recent years, the study onthe conversion of CO2 into a wide variety of C2+ important chemicals and fuels has received considerable attentionas an emerging technology. Since CO2 is thermodynamically stable and kinetically inert, the effective activationof CO2 molecule for the selective transformation to target products still remains a challenge. The welldesigned CO2 reduction route and efficient catalyst system has imposed the feasibility of CO2 conversion into C2+ chemicals and fuels. In this paper, we have reviewed the recent advances on chemical conversion of CO2 into C2+ chemicals and fuelswith wide practical applications, including important alcohols, acetic acid, dimethylether, olefins and gasoline. In particular, the synthetic routes for C-C coupling and carbon chain growth, multifunctionalcatalyst design and reaction mechanisms are exclusively emphasized

Bioengineered Bacterial Flagella-Templated in Situ Green Synthesis of Polycrystalline Co₃O₄ Nanowires for Gram-Negative Antibacterial Applications

In recent years, considerable progress has been made on the synthetic chemistry and antibacterial application of tricobalt tetroxide (Co3O4) nanomaterials. However, the current approaches to designing and synthesizing Co3O4 nanomaterials are complicated and hard to manipulate. Herein, we developed a one-pot strategy to synthesize Co3O4 nanowires at room temperature with an antibacterial activity. The synthesis process relied on the use of engineered bacterial flagella as a biotemplate, which were genetically modifiable protein nanofibers naturally attached to bacteria for assisting their swimming. We found that the flagella displaying negatively charged peptides (E10 and E20) effectively induced the nucleation of Co3O4 nanoparticles from a cobalt chloride (CoCl2) precursor solution on their surface to form polycrystalline nanowires, with the E20-flagella being more effective than the E10-flagella. However, the wildtype flagella or those displaying neutral (G10) or positively charged (K5) peptides did not effectively induce the Co3O4 nucleation on the flagella. A mechanism investigation discovered that an amorphous phase of Co3O4 was first formed rapidly on the E20-flagella, followed by a crystallization process with both the good crystallinity and nanowire water-dispersibility reached in 2 h. We also found that the E20-flagella formed the Co3O4 nanowires with the good crystallinity at a precursor solution of 1 mM. The E20-flagella-templated Co3O4 nanowires, synthesized using the optimal mineralization conditions (2 h and 1 mM CoCl2), showed the most effective killing of Gram-negative bacteria such as Escherichia coli. This work suggests that flagella with tunable peptide sequences are biotemplates for forming antibacterial nanowires at environmentally benign conditions

Effects of <i>Oenanthe javanica</i> on Nitrogen Removal in Free-Water Surface Constructed Wetlands under Low-Temperature Conditions

To investigate the role and microorganism-related mechanisms of macrophytes and assess the feasibility of Oenanthe javanica (Blume) DC. in promoting nitrogen removal in free-water surface constructed wetlands (FWS-CWS) under low temperatures (&lt;10 &#176;C), pilot-scale FWS-CWS, planted with O. javanica, were set up and run for batch wastewater treatment in eastern China during winter. The presence of macrophytes observably improved the removal rates of ammonia nitrogen (65%&#8211;71%) and total nitrogen (41%&#8211;48%) (p &lt; 0.05), with a sharp increase in chemical oxygen demand concentrations (about 3&#8211;4 times). Compared to the unplanted systems, the planted systems not only exhibited higher richness and diversity of microorganisms, but also significantly higher abundances of bacteria, ammonia monooxygenase gene (amoA), nitrous oxide reductase gene (nosZ), dissimilatory cd1-containing nitrite reductase gene (nirS), and dissimilatory copper-containing nitrite reductase gene (nirK) in the substrate. Meanwhile, the analysis of the microbial community composition further revealed significant differences. The results indicate that enhanced abundances of microorganisms, and the key functional genes involved with nitrogen metabolism in the planted systems played critical roles in nitrogen removal from wastewater in FWS-CWS. Furthermore, abundant carbon release from the wetland macrophytes could potentially aid nitrogen removal in FWS-CWS during winter

Effects of Naphthalene Application on Soil Fungal Community Structure in a Poplar Plantation in Northern Jiangsu, China

The soil food web is essential for the functioning of terrestrial ecosystems. The application of naphthalene is a commonly employed experimental treatment for expelling soil fauna to examine faunal effects on litter decomposition processes, for which is it assumed that naphthalene has negligible effects on soil microbial communities. An experiment was conducted to examine the potential soil-fauna-repellent effect of naphthalene application (100 g/m2/month, TR) on a soil fungal community during litter decomposition. The results showed that TR greatly suppressed the abundance and taxonomic richness of soil fauna by 83.7 ± 14.2% and 48.1 ± 17.2%, respectively, and reduced the rates of poplar leaf litter decomposition compared to the control (CK, without naphthalene treatment). Among the fungal communities, the abundance of Thelephorales in the TR soil was suppressed, while the abundance of Capnodiales was stimulated, although TR did not significantly alter the carbon and nitrogen content in the soil microbial biomass nor the diversity of soil fungal communities and the most abundant fungal phylum. Thus, both the suppressed soil arthropod abundance and altered soil fungal community might contribute to the observed slowdown in litter decomposition. These results suggest that naphthalene, as a soil fauna repellent, can alter the abundance of specific taxa in a soil fungal community, thereby impeding the effort to elucidate the contribution of soil fauna to ecosystem functioning (e.g., with respect to litter decomposition)

R2DE: A NLP approach to estimating IRT parameters of newly generated questions

The main objective of exams consists in performing an assessment of students' expertise on a specific subject. Such expertise, also referred to as skill or knowledge level, can then be leveraged in different ways (e.g., to assign a grade to the students, to understand whether a student might need some support, etc.). Similarly, the questions appearing in the exams have to be assessed in some way before being used to evaluate students. Standard approaches to questions' assessment are either subjective (e.g., assessment by human experts) or introduce a long delay in the process of question generation (e.g., pretesting with real students). In this work we introduce R2DE (which is a Regressor for Difficulty and Discrimination Estimation), a model capable of assessing newly generated multiple-choice questions by looking at the text of the question and the text of the possible choices. In particular, it can estimate the difficulty and the discrimination of each question, as they are defined in Item Response Theory. We also present the results of extensive experiments we carried out on a real world large scale dataset coming from an e-learning platform, showing that our model can be used to perform an initial assessment of newly created questions and ease some of the problems that arise in question generation. © 2020 Copyright held by the owner/author(s)

Growth and physiological responses of submerged plant Vallisneria natans to water column ammonia nitrogen and sediment copper

Background. The decline of submerged plant populations due to high heavy metal (e.g., Cu) levels in sediments and ammonia nitrogen (ammonia-N) accumulation in the freshwater column has become a significant global problem. Previous studies have evaluated the effect of ammonia-N on submerged macrophytes, but few have focused on the influence of sediment Cu on submerged macrophytes and their combined effects. Methods. In this paper, we selected three levels of ammonia-N (0, 3, and 6 mg L−1) and sediment Cu (25.75 ± 6.02 as the control, 125.75 ± 6.02, and 225.75 ± 6.02 mg kg−1), to investigate the influence of sediment Cu and ammonia-N on submerged Vallisneria natans. We measured the relative growth rate (RGR), above- and below- ground biomass, chlorophyll, non-protein thiol (NP-SH), and free proline. Results and Discussion. The below-ground biomass of V. natans decreased with increasing Cu sediment levels, suggesting that excessive sediment Cu can result in significant damage to the root of V. natans. Similarly, the above-ground biomass significantly decreased with increasing ammonia-N concentrations, indicating that excessive water ammonia-N can cause significant toxicity to the leaf of V. natans. In addition, high ammonia-N levels place a greater stress on submerged plants than sediment Cu, which is indicated by the decline of RGR and chlorophyll, and the increase of (NP-SH) and free proline. Furthermore, high sediment Cu causes ammonia-N to impose greater injury on submerged plants, and higher sediment Cu levels (Cu ≥ 125.75 mg kg−1) led to the tolerant values of ammonia-N for V. natans decreasing from 6 to 3 mg L−1. This study suggests that high sediment Cu restricts the growth of plants and intensifies ammonia-N damage to V. natans