The Critical Discourse Analysis of Language Teacher’s Instructional Decisions

Teacher’s decision making is an instant indicator of the discourse activities in the context of education. A critical discourse analysis of the language teacher’s classroom decisions is able to give an insight into the essence of discourse of teacher authority, power, and morality sneaking in classroom teaching at the micro and macro levels, and then understand the force that the hidden power of discourse relations acts on the subject and the object of teaching in the field of educational discourse, the way school discourse communicates as well, hoping teachers, students, language, knowledge being in harmony and free in the context of education

Soft-Decision-Driven Sparse Channel Estimation and Turbo Equalization for MIMO Underwater Acoustic Communications

Multi-input multi-output (MIMO) detection based on turbo principle has been shown to provide a great enhancement in the throughput and reliability of underwater acoustic (UWA) communication systems. Benefits of the iterative detection in MIMO systems, however, can be obtained only when a high quality channel estimation is ensured. In this paper, we develop a new soft-decision-driven sparse channel estimation and turbo equalization scheme in the triply selective MIMO UWA. First, the Homotopy recursive least square dichotomous coordinate descent (Homotopy RLS-DCD) adaptive algorithm, recently proposed for sparse single-input single-output system identification, is extended to adaptively estimate rapid time-varying MIMO sparse channels. Next, the more reliable a posteriori soft-decision symbols, instead of the hard decision symbols or the a priori soft-decision symbols, at the equalizer output, are not only feedback to the Homotopy RLS-DCD-based channel estimator but also to the minimum mean-square-error (MMSE) equalizer. As the turbo iterations progress, the accuracy of channel estimation and the quality of the MMSE equalizer are improved gradually, leading to the enhancement in the turbo equalization performance. This also allows the reduction in pilot overhead. The proposed receiver has been tested by using the data collected from the SHLake2013 experiment. The performance of the receiver is evaluated for various modulation schemes, channel estimators, and MIMO sizes. Experimental results demonstrate that the proposed a posteriori soft-decision-driven sparse channel estimation based on the Homotopy RLS-DCD algorithm and turbo equalization offer considerable improvement in system performance over other turbo equalization schemes

MMP-DCD-CV based Sparse Channel Estimation Algorithm for Underwater Acoustic Transform Domain Communication System

In this paper, we propose a computationally efficient multipath matching pursuit (MMP) channel estimation algorithm for underwater acoustic (UWA) transform domain communication systems (TDCSs). The algorithm, referred to as the MMP-DCD-CV algorithm, is based on the dichotomous coordinate descent (DCD) iterations and cross validation (CV). The MMP-DCD-CV sparse channel estimator in each iteration searches for multiple promising path candidates most relevant to a residual vector and chooses the best candidate. The DCD iterations are used to solve the corresponding least squares problem with low complexity and numerical stability. The CV provides a stopping criterion of the algorithm without a priori information on the channel sparsity and noise level and examines whether the algorithm overfits its data, thus improving the estimation accuracy. The performance of the proposed algorithm is evaluated under simulated sparse UWA channels. The numerical results show that the algorithm achieves better performance than the original MMP algorithm, has lower complexity, and does not require prior knowledge on the channel sparsity and noise level. We also propose an UWA TDCS with sparse channel estimation based on the proposed MMP-DCD-CV algorithm. The proposed UWA communication system is tested by the Waymark simulator, providing the virtual signal transmission in the UWA channel, with a measured Sound Speed Profile and bathymetry. Numerical results demonstrate that the UWA TDCS with the proposed sparse channel estimator offers considerable improvement in system performance compared to other TDCS schemes

Hypericin enhances β-lactam antibiotics activity by inhibiting sarA expression in methicillin-resistant Staphylococcus aureus.

Bacteremia is a life-threating syndrome often caused by methicillin-resistant Staphylococcus aureus (MRSA). Thus, there is an urgent need to develop novel approaches to successfully treat this infection. Staphylococcal accessory regulator A (SarA), a global virulence regulator, plays a critical role in pathogenesis and β-lactam antibiotic resistance in Staphylococcus aureus. Hypericin is believed to act as an antibiotic, antidepressant, antiviral and non-specific kinase inhibitor. In the current study, we investigated the impact of hypericin on β-lactam antibiotics susceptibility and mechanism(s) of its activity. We demonstrated that hypericin significantly decreased the minimum inhibitory concentrations of β-lactam antibiotics (e.g., oxacillin, cefazolin and nafcillin), biofilm formation and fibronectin binding in MRSA strain JE2. In addition, hypericin significantly reduced sarA expression, and subsequently decreased mecA, and virulence-related regulators (e.g., agr RNAⅢ) and genes (e.g., fnbA and hla) expression in the studied MRSA strain. Importantly, the in vitro synergistic effect of hypericin with β-lactam antibiotic (e.g., oxacillin) translated into in vivo therapeutic outcome in a murine MRSA bacteremia model. These findings suggest that hypericin plays an important role in abrogation of β-lactam resistance against MRSA through sarA inhibition, and may allow us to repurpose the use of β-lactam antibiotics, which are normally ineffective in the treatment of MRSA infections (e.g., oxacillin)

The risk factors and impact of subchorionic hematoma in the first trimester in IVF twin pregnancies: a prospective cohort study

ObjectiveThis study aimed to identify the risk factors for subchorionic hematoma (SCH) in the first trimester of in vitro fertilization (IVF) twin pregnancies and investigate the impact of SCH on pregnancy outcomes.Study designA prospective cohort study was conducted at Chengdu Women and Children's Central Hospital. The study recruited patients who were identified with twin pregnancies in the first trimester, undergoing IVF treatment from January 2020 to May 2021. The demographic characteristics and pregnancy outcomes were compared between the SCH and the non-SCH groups. A logistic regression analysis was used to determine the risk factors for SCH and adverse pregnancy outcomes.ResultsIn the first trimester, 38% of patients developed SCH. The independent risk factors for SCH included male factor, hydrosalpinx, polycystic ovary syndrome (PCOS), previous miscarriage, and adenomyosis. With respect to the pregnancy outcomes, only the rate of twin pregnancy loss before 20 gestational weeks was significantly higher in the SCH group than in the non-SCH group. After adjusting for the confounding factors, the presence of SCH diminished the ovarian reserve, and previous miscarriage was independently related to twin pregnancy loss before 20 gestational weeks.ConclusionThis may be the first study to evaluate the risk factors of SCH in twin pregnancies who underwent IVF-ET/FET treatment, which may provide some theoretical basis for clinical practice in the future. Furthermore, it was found that the occurrence of SCH was associated with the loss of both pregnancies before 20 gestational weeks. Therefore, these patients should be offered increased surveillance and timely treatment

Model of defect formation in annealed undoped and Fe-doped liquid encapsulated Czochralski InP

Infrared absorption spectroscopy measurements indicate high concentration of hydrogen indium vacancy complex VInH4 in undoped and Fe-doped liquid encapsulated Czochralski (LEC) InP. Annealed undoped and Fe-doped semi-insulating (SI) InP are studied by room temperature Hall effect measurement and photocurrent spectroscopy. The results show that a mid gap donor defect and some shallow intrinsic defects are formed by high temperature annealing. This mid gap defect is shown to be phosphorus antisite related. Defect formation process and compensation mechanism in annealed SI InP are discussed.published_or_final_versio

Multiwalled carbon nanotubes co-delivering sorafenib and epidermal growth factor receptor siRNA enhanced tumor-suppressing effect on liver cancer.

OBJECTIVE: This study aimed to investigate the effects of multiwalled carbon nanotubes (MWNTs) co-delivering sorafenib (Sor) and epidermal growth factor receptor (EGFR) siRNA (MWNT/Sor/siRNA) on tumor growth in liver cancer (LC). RESULTS: MWNT/Sor/siRNA was proved to possess increased Sor release, high siRNA stability, and enhanced cellular uptake. In addition, MWNT treatment has few effects on cell proliferation and apoptosis in HepG2 cells; however, MWNT/Sor/siRNA treatment significantly inhibited clone number and induced cell apoptosis, which shows a more favorable antitumor effect than MWNT/Sor and free Sor and free siRNA in HepG2 cells. Moreover MWNT/Sor/siRNA treatment has the most significant antitumor effect CONCLUSIONS: MWNT/Sor/siRNA exhibited a superior antitumor effect METHODS: The MWNT/Sor and MWNT/Sor/siRNA were prepared, and then the morphologies of MWNT/Sor/siRNA were analyzed