Integrating Second Life into an EFL Program: Students’ Perspectives

Second Life (SL) is a three dimension virtual world imagined and created by its users. To explore various facets of language learning within SL, faculty members of an American university and a Chinese university took an evaluation research approach to search for appropriate ways to integrate SL into an EFL (English as a Foreign Language) program. This paper reports a part of the research efforts with a focus on the Chinese students’ perspectives of an EFL Program in SL. Specifically included in this paper are (a) the Chinese students’ perceived technology readiness to use SL for EFL learning, (b) their perceptions of SL, and (c) the EFL Program implemented in SL. The paper reviews related literature and theoretical support, describes the study’s context and its implementation procedures, and discusses the evaluation results and implications. Finally, the paper shares with the audience some considerations for integrating SL into an EFL progra

Recent Advances in the mm-Wave Array for Mobile Phones

With the development of communication system to the mm-wave band, the antenna design in the mm-wave band for mobile phones encounters new requirements and challenges. The mm-wave characteristics of short wavelength, high free-space path loss, and easy-to-be-blocking usually require mm-wave antennas with high gain and beam-scanning capability. Also, considering the very limited space occupied by antennas in mobile phones and the massive production of consumer electronics, small size, low cost, multiband, multi-polarization, and wide beam steering becomes the main key point of mm-wave array performance. In addition, as a special situation of the mobile antenna, the analysis of effect of the human tissue on the antenna performance is also important. So, in this chapter, a comprehensive summary on the recent advances in the mm-wave array for mobile phones including single-band, dual-band, and reconfigurable design of broadside array, horizontal polarized, vertical polarized, and dual-polarized design of endfire array, co-design of mm-wave array with lower band antenna, and user influence are summarized

Fully packed quantum loop model on the square lattice: phase diagram and application for Rydberg atoms

The quantum dimer and loop models attract great attentions, partially because the fundamental importance in the novel phases and phase transitions emerging in these prototypical constrained systems; and partially due to their intimate relevance towards the on-going experiments on Rydberg atom arrays in which the blockade mechanism naturally enforces the local constraint. Here we show, by means of the sweeping cluster quantum Monte Carlo method, the complete ground state phase diagram of the fully packed quantum loop model on the square lattice. We find between the lattice nematic (LN) phase with strong dimer attraction and the staggered phase (SP) with strong dimer repulsion, there emerges a resonating plaquette (RP) phase with off-diagonal translational symmetry breaking. Such a novel phase is separated from the LN via a first order transition and from the SP by the famous Rokhsar-Kivelson point. Our renormalization group analysis reveals the different flow directions, fully consistent with the order parameter histogram in Monte Carlo simulations. The realization and implication of our phase diagram in Rydberg experiments are proposed.Comment: 6+2 pages, 5+2 figure

Classical model emerges in quantum entanglement: Quantum Monte Carlo study for an Ising-Heisenberg bilayer

By developing a cluster sampling of stochastic series expansion quantum Monte Carlo method, we investigate a spin-$1/2$ model on a bilayer square lattice with intra-layer ferromagnetic (FM) Ising coupling and inter-layer antiferromagnetic Heisenberg interaction. The continuous quantum phase transition which occurs at $g_c=3.045(2)$ between the FM Ising phase and the dimerized phase is studied via large scale simulations. From the analyzes of critical exponents we show that this phase transition belongs to the (2+1)-dimensional Ising universality class. Besides, the quantum entanglement is strong between the two layers, especially in dimerized phase. The effective Hamiltonian of single layer seems like a transverse field Ising model. However, we found the quantum entanglement Hamiltonian is a pure classical Ising model without any quantum fluctuations. Furthermore, we give a more general explanation about how a classical entanglement Hamiltonian emerges

Effects of rescue gloves on hand skin temperature and manual performance under local cold exposure

BackgroundCold environments reduce work efficiency and increase the risk of frostbite. ObjectiveTo investigate the effects on cold protection and manual performance of rescue gloves in cold environments, and to preliminarily verify the feasibility of related quantitative characterization methods. MethodsAn experiment was conducted in a large and a small artificial climate chamber. 12 male right-handed university students were recruited. The experiment was divided into two parts, with 0-10 min as the baseline phase and 10-50 min as the test phase. Subjects sat quietly in a 16 ℃ large chamber, and hands were exposed to a small chamber at 0 ℃ either barely (control group) or with rescue gloves (experimental group). Skin temperatures of the five fingers (thumb, index finger, middle finger, ring finger, and little finger), as well as the dorsal and palm of the hands were measured. In addition, grip strength, manual dexterity, maximum finger flexion, and tactile sensitivity of the hands were measured as the indicators of manual performance. ResultsIn the control group, cold-induced vasodilation occurred when the skin temperature of the five fingers were lowered to about 10 ℃. The maximum rate of change in skin temperature of the control group was in the following order: thumb＞index finger＞middle finger＞little finger＞ring finger＞dorsal＞palm, 165.7 ℃·h−1 in the thumb, 80.0 and 89.9 ℃·h−1 in the palm and dorsal respectively. In addition, the minimum skin temperature of the thumb was 6.6 ℃. Compared with the control group: the rate of change of skin temperature in the experimentalgroup decreased by about 50%; the grip strength decreased by 15% after wearing the rescue gloves (P0.05). ConclusionThis study proved that the rescue gloves improved the thermal comfort of hands while better balancing the effect of cold exposure on manual performance. The quantitative characterization methods can evaluate the protective performance and manual performance of the rescue gloves, which provides a reliable theoretical foundation and reference basis for further experiments

Superpixel-Based Attention Graph Neural Network for Semantic Segmentation in Aerial Images

Semantic segmentation is one of the significant tasks in understanding aerial images with high spatial resolution. Recently, Graph Neural Network (GNN) and attention mechanism have achieved excellent performance in semantic segmentation tasks in general images and been applied to aerial images. In this paper, we propose a novel Superpixel-based Attention Graph Neural Network (SAGNN) for semantic segmentation of high spatial resolution aerial images. A K-Nearest Neighbor (KNN) graph is constructed from our network for each image, where each node corresponds to a superpixel in the image and is associated with a hidden representation vector. On this basis, the initialization of the hidden representation vector is the appearance feature extracted by a unary Convolutional Neural Network (CNN) from the image. Moreover, relying on the attention mechanism and recursive functions, each node can update its hidden representation according to the current state and the incoming information from its neighbors. The final representation of each node is used to predict the semantic class of each superpixel. The attention mechanism enables graph nodes to differentially aggregate neighbor information, which can extract higher-quality features. Furthermore, the superpixels not only save computational resources, but also maintain object boundary to achieve more accurate predictions. The accuracy of our model on the Potsdam and Vaihingen public datasets exceeds all benchmark approaches, reaching 90.23% and 89.32%, respectively

A review on fundamentals for designing hydrogen evolution electrocatalyst

As a clean, efficient, and renewable energy source, hydrogen has always been recognized as a favourable replacement of fossil fuel. A primary challenge is an efficient generation of hydrogen to fulfil the requirements of hydrogen on a commercial scale. The electrocatalytic process of HER (hydrogen evolution reaction), as primary phase in water electrolytic process for H2 production, has undergone comprehensive observation from recent decades. Electrolytic water splitting presents a promised route to attain efficient hydrogen generation concerning energy conversion and storage, with electrolysis or catalysis playing a pivotal role. The advancement of catalyst or electrocatalysts that are effective, enduring and economical is necessary prerequisite for realizing the intended electrolytic hydrogen generation from water splitting for applicable considerations, embodying the primary emphasis of this article. In this extensive review, we initially summarize the basics of the Hydrogen evolution reaction and examine the latest cutting-edge progress in economical and highly efficiency catalysts utilizing both non-noble and noble metals. Moreover, the recent breakthroughs over the preceding years in electrolytic HER employing more affordable and widely available nanoparticles with a specific center of attention on economical and non-platinum electrocatalysts rooted in metal free (MF) and transition metal composite catalysts are deliberated here

YiQiFuMai Powder Injection Attenuates Coronary Artery Ligation-Induced Heart Failure Through Improving Mitochondrial Function via Regulating ROS Generation and CaMKII Signaling Pathways

The YiQiFuMai powder injection (YQFM), a traditional Chinese medicine (TCM) prescription re-developed based on Sheng-Mai-San, is widely applied for the treatment of cardiovascular diseases. However, its potential molecular mechanism remains obscure. The present study was designed to observe the effects of YQFM and underlying mechanisms on coronary artery ligation (CAL)-induced heart failure (HF) and cell hypoxia of 24 h oxygen-glucose deprivation (OGD) in neonatal rat ventricular myocytes (NRVMs). HF was induced by permanent CAL for 2 weeks in ICR mice. The results demonstrated that YQFM significantly attenuated CAL-induced HF via improving the cardiac function, cardiac systolic function, cardiac structure impairment, cardiac histological features and fibrosis. YQFM markedly attenuated mitochondrial dysfunction through improving mitochondrial morphology, increasing mitochondria membrane potential (Δψm), mitochondrial ROS generation and expression of Mitofusin-2 (Mfn2), meanwhile, decreasing phosphorylation of dynamin-related protein 1 (p-Drp1). Mechanistically, YQFM could significantly decrease the expression of isoforms of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit NADPH oxidase 2 (NOX2), p67phox and NADPH oxidase 4 (NOX4), ultimately reducing reactive oxygen species (ROS) generation. In addition, YQFM could down-regulate expression of calcium voltage-gated channel subunit α1C (CACNA1C) and phosphorylation of calmodulin dependent protein kinase II (p-CaMKII). These results suggest that YQFM ameliorates mitochondrial function in HF mice, partially through inhibiting ROS generation and CaMKII signaling pathways. Therefore, the present study provided scientific evidence for the underlying mechanism of YQFM

Cardiac sympathetic overdrive, M2 macrophage activation and fibroblast heterogeneity are associated with cardiac remodeling in a chronic pressure overload rat model of HFpEF

Heart failure with preserved ejection fraction (HFpEF) is a multifaceted pathogenesis disease and the exact mechanisms driving HFpEF have not been completely elucidated. Pressure overload hypertrophy (POH) related fibroblasts and M2 macrophages in HFpEF myocardium have been recently identified and are now of great interest. Sympathetic overdrive has also been implicated in HFpEF. This study is designed to dynamically observe the potential roles of aforementioned mechanisms in pathological remodeling and cardiac dysfunction in chronic PO rats. Surgical constriction of the abdominal aorta was used for induction of HFpEF. Echocardiography, electrocardiogram, hemodynamic measurement, hematoxylin and eosin staining, Masson staining, immunohistochemistry and immunofluorescence were performed to assess the changes in heart dysfunction, cardiac remodeling and driving mechanisms at different time points (2, 18, 24 weeks). The PO induced HFpEF model was well established, which was confirmed by the persistent increase in carotid artery systolic and diastolic blood pressure, and left ventricle hypertrophy at the corresponding postoperative stage. Meanwhile, PO hypertrophy gradually developed into HFpEF, associated with QT and QTc intervals prolongation, normal systolic (EF was maintained at >50%) but impaired diastolic function (increasing LVEDP and LV -dP/dtmin, abnormal E/A ratio), increased myocytes size, and observed relatively slight inflammatory infiltration but robust reactive fibrosis. IHC staining further confirmed that macrophages (CD68) but not neutrophils (MPO) or T cells (CD3) accounted for a predominant proportion of infiltrating cells. Mechanistically, we found that the infiltrating macrophages in the heart expressed high levels of CD206 which was simultaneously adjacent to POH fibroblasts appeared to overexpression of α-SMA in PO rats at late stages. Interestingly, we distinguished two different POHF sub-populations during PO induced HFpEF development, according to non overlapping signals of α-SMA and PDGFRα/β proteins. Additionally, PO led to a pronounced exaggeration in sympathetic fibers at all time points. These findings suggest that the establishing model here begins with cardiac sympathetic overdrive, subsequently along with immune cells especially M2 macrophage accumulation and fibroblast heterogeneity at later stages is associated with the development of cardiac maladaptive remodeling and diastolic dysfunction thus further progression to HFpEF