810 research outputs found

    THE EFFECTS OF SELF-EFFICACY ON LEARNERS’ PERCEPTIONS OF COGNITIVE PRESENCE IN ONLINE COLLABORATIVE LEARNING ACTIVITIES

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    The applications of web2.0 platforms provide online learning opportunities to focus more on community collaborations as well as the knowledge construction. Cognitive presence (CP) is one of the most critical elements of community of inquiry, and ideal learning outcomes would require deeper stages of cognitive presence (integration and resolution stages), that usually difficult to achieve. Past research on CP felt short in investigating the influences of individual differences, including the effects of learners’ internal motivation on higher-order thinking. We consider Self-efficacy is one of such as it emphasizes a combination of learners’ motivation and cognition. This study intends to explore the influence of learners’ online learning self-efficacy on CP, as well as to explore the relationship between learners’ CP and learning achievements.An experiment was conducted to verify the above issues. Participants were 8th graders from a vocational school. They were required to complete their learning tasks through online collaboration by Facebook and Google Cloud. Questionnaires were applied to measure learners’ CP and self-efficacy after study. Results show that phase’s distribution of learners’ CP in this study is satisfying, and there are significant correlations between CP and self-efficacy as well as CP and learning achievements. Therefore, this study suggests that instructors should take different strategies for students with different self-efficacy and take some strategies which can enhance self-efficacy.&nbsp

    Integrating spatial and temporal approaches for explaining bicycle crashes in high-risk areas in Antwerp (Belgium)

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    The majority of bicycle crash studies aim at determining risk factors and estimating crash risks by employing statistics. Accordingly, the goal of this paper is to evaluate bicycle-motor vehicle crashes by using spatial and temporal approaches to statistical data. The spatial approach (a weighted kernel density estimation approach) preliminarily estimates crash risks at the macro level, thereby avoiding the expensive work of collecting traffic counts; meanwhile, the temporal approach (negative binomial regression approach) focuses on crash data that occurred on urban arterials and includes traffic exposure at the micro level. The crash risk and risk factors of arterial roads associated with bicycle facilities and road environments were assessed using a database built from field surveys and five government agencies. This study analysed 4120 geocoded bicycle crashes in the city of Antwerp (CA, Belgium). The data sets covered five years (2014 to 2018), including all bicycle-motorized vehicle (BMV) crashes from police reports. Urban arterials were highlighted as high-risk areas through the spatial approach. This was as expected given that, due to heavy traffic and limited road space, bicycle facilities on arterial roads face many design problems. Through spatial and temporal approaches, the environmental characteristics of bicycle crashes on arterial roads were analysed at the micro level. Finally, this paper provides an insight that can be used by both the geography and transport fields to improve cycling safety on urban arterial roads

    Determination of direction of littoral transport along the north shore of Santa Rosa Island, Florida

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    The purpose of this study was to determine the actual direction of littoral transport along the north shore of Santa Rosa Island in the vicinity of Pensacola Beach, Florida. To accomplish this objective the sand tracer method was used for the study. Visual observations and instrument recordings of the environment factors were also made during the tracing operations. The investigation covered a time span from September 14, 1976 to March 12, 1977. (PDF contains 68 pages.

    Rapid and sensitive insulated isothermal PCR for point-of-need feline leukaemia virus detection

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    Objectives: Feline leukaemia virus (FeLV), a gamma retrovirus, causes diseases of the feline haematopoietic system that are invariably fatal. Rapid and accurate testing at the point-of-need (PON) supports prevention of virus spread and management of clinical disease. This study evaluated the performance of an insulated isothermal PCR (iiPCR) that detects proviral DNA, and a reverse transcription (RT)-iiPCR that detects both viral RNA and proviral DNA, for FeLV detection at the PON. Methods: Mycoplasma haemofelis, feline coronavirus, feline herpesvirus, feline calicivirus and feline immunodeficiency virus were used to test analytical specificity. In vitro transcribed RNA, artificial plasmid, FeLV strain American Type Culture Collection VR-719 and a clinical FeLV isolate were used in the analytical sensitivity assays. A retrospective study including 116 clinical plasma and serum samples that had been tested with virus isolation, real-time PCR and ELISA, and a prospective study including 150 clinical plasma and serum samples were implemented to evaluate the clinical performances of the iiPCR-based methods for FeLV detection. Results: Ninety-five percent assay limit of detection was calculated to be 16 RNA and five DNA copies for the RT-iiPCR, and six DNA copies for the iiPCR. Both reactions had analytical sensitivity comparable to a reference real-time PCR (qPCR) and did not detect five non-target feline pathogens. The clinical performance of the RT-iiPCR and iiPCR had 98.82% agreement (kappa[Îș] = 0.97) and 100% agreement (Îș = 1.0), respectively, with the qPCR (n = 85). The agreement between an automatic nucleic extraction/RT-iiPCR system and virus isolation to detect FeLV in plasma or serum was 95.69% (Îș = 0.95) and 98.67% (Îș = 0.85) in a retrospective (n = 116) and a prospective (n = 150) study, respectively. Conclusions and relevance: These results suggested that both RT-iiPCR and iiPCR assays can serve as reliable tools for PON FeLV detection

    Fractal and Morlet-wavelet analyses of M ≄ 6 earthquakes in the South-North Seismic Belt, China

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    The M ≄ 6 earthquakes occurred in the South-North Seismic Belt, Mainland China (longitudes from 98 - 107°E and latitudes from 21 - 41°N) during 1900 - 2016 are taken to measure the multifractal dimensionsspatial distribution and time sequence of events and the dominant periods. The multifractal dimensions, Dq, are measured from the log-log plots of Cq(r) versus r and Cq(t) versus t, where Cq(r) and Cq(t) are the generalized correlation integrals for the epicentral distribution and time sequence of events, respectively. r and t are the epicentral distance and inter-event time, respectively, at positive q. The log-log plot of Cq(r) versus r shows a linear por­tion when log(rl) ≀ log(r) ≀ log(ru). The rl and ru values are, respectively, 120 and 560 km for M ≄ 6 events, 100 and 560 km for M ≄ 6.5 events, and 63 and 560 km for M ≄ 7 events. The rl value decreases with the lower-bound magnitude. Dq monotonically decreases with increasing q. The Dq values are between 1.618 and 1.426 for M ≄ 6 events, between 1.562 and 1.108 for M ≄ 6.5 events, and between 1.365 and 0.841 for M ≄ 7 events. The log-log plot Cq(t) versus t show a linear distribution when log(tl) ≀ log(t) ≀ log(tu), where tl and tu are, respectively, 5 and 50.1 years for M ≄ 6 events, 5 and 50.1 years for M ≄ 6.5 events, and 16 and 63.1 years for M ≄ 7 event, thus sug­gesting that the time sequences of earthquake in the study region are multifractal. The Dq values are between 0.830 and 0.703 for M ≄ 6 events, between 0.835 and 0.820 for M ≄ 6.5 events, and between 0.786 and 0.685 for M ≄ 7 events. The Morlet wavelet technique is applied to analyze the dominant periods of temporal variations in num­bers of yearly earthquakes for the three magnitude ranges, i.e., M ≄ 6, M ≄ 6.5, and M ≄ 7. The resultant dominant period is 2.94 years for M ≄ 6 events and cannot be evaluated for M ≄ 6.5 and M ≄ 7 events

    Treatment selection for tonsillar squamous cell carcinoma

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    AbstractBackgroundThe optimal treatment for tonsillar squamous cell carcinoma (SCC) remains controversial. The purpose of this study was to evaluate long-term treatment outcomes of patients with tonsillar SCC, in order to aid in appropriate treatment selection.MethodsWe conducted a retrospective chart review of 105 patients with curatively treated tonsillar SCC between January 1996 and December 2005. Forty-three patients (41.0%) underwent primary surgery with or without adjuvant therapy (primary surgery group), and 62 patients (59.0%) were treated with radiotherapy/chemoradiotherapy (RT/CRT, organ preservation group). Twenty patients (19%) received tumor tonsillectomy before definitive RT/CRT and were grouped into the organ preservation group.ResultsNo significant differences were observed between the primary surgery and organ preservation groups in terms of local control (p = 0.212), regional control (p = 0.684), distant metastasis (p = 0.627), 5-year disease-specific survival (DSS, p = 0.774), and overall survival rates (OS, p = 0.667). The rates of major complication (p = 0.216), long-term dependency on feeding tubes (p = 0.876), and tracheostomy (p = 0.401) were also similar. Advanced T classification (T3–4) was the only factor associated with significantly worse DSS (p = 0.007) and OS (p = 0.012). However, there was also no difference in final treatment outcomes in T3–4 patients regardless of whether they were treated with primary surgery or RT/CRT. In the organ preservation group, tumor tonsillectomy before RT/CRT did not improve local control (p = 0.520) or other treatment outcomes, including 5-year DSS (p = 0.707) and OS (p = 0.745).ConclusionBoth primary surgery and RT/CRT organ preservation are effective treatments for tonsillar SCC. Single modality treatment, either surgery or RT/CRT, can typically be provided for stage I–II diseases. Although RT/CRT organ preservation is used more frequently for stage III–IV tonsillar SCC in recent years, primary surgery combined with adjuvant therapy still achieves equivalent outcomes. Multidisciplinary pretreatment counseling and the facilities and personnel available are therefore important for decision-making. In addition, if RT/CRT organ preservation is selected as the primary treatment, tumor tonsillectomy is not indicated

    Biomechanical Analysis of Landing from Counter Movement Jump and Vertical Jump with Run-Up in the Individuals with Functional Ankle Instability

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    Ankle sprain is one of the most common sport injuries in lower extremities. It frequently occurs in landing phase when athletes perform jumping. The counter movement jump and straddle jump are common jumping strategies often used in baseball and volleyba

    A hybrid Si@FeSiy/SiOx anode structure for high performance lithium-ion batteries via ammonia-assisted one-pot synthesis

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    Synthesised via planetary ball-milling of Si and Fe powders in an ammonia (NH3) environment, a hybrid Si@FeSiy/SiOx structure shows exceptional electrochemical properties for lithium-ion battery anodes, exhibiting a high initial capacity of 1150 mA h g−1 and a retention capacity of 880 mA h g−1 after 150 cycles at 100 mA g−1; and a capacity of 560 mA h g−1 at 4000 mA g−1. These are considerably high for carbon-free micro-/submicro-Si-based anodes. NH3 gradually turns into N2 and H2 during the synthesis, which facilitates the formation of highly conductive FeSiy (y = 1, 2) phases, whereas such phases were not formed in an Ar atmosphere. Milling for 20–40 h leads to partial decomposition of NH3 in the atmosphere, and a hybrid structure of a Si core of mixed nanocrystalline and amorphous Si domains, shelled by a relatively thick SiOx layer with embedded FeSi nanocrystallites. Milling for 60–100 h results in full decomposition of NH3 and a hybrid structure of a much-refined Si-rich core surrounded by a mantle of a relatively low level of SiOx and a higher level of FeSi2. The formation mechanisms of the SiOx and FeSiy phases are explored. The latter structure offers an optimum combination of the high capacity of a nanostructural Si core, relatively high electric conductivity of the FeSiy phase and high structural stability of a SiOx shell accommodating the volume change for high performance electrodes. The synthesis method is new and indispensable for the large-scale production of high-performance Si-based anode materials

    Modified Weekly Cisplatin-Based Chemotherapy Is Acceptable in Postoperative Concurrent Chemoradiotherapy for Locally Advanced Head and Neck Cancer

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    Background. Triweekly cisplatin-based postoperative concurrent chemoradiotherapy (CCRT) has high intolerance and toxicities in locally advanced head and neck cancer (LAHNC). We evaluated the effect of a modified weekly cisplatin-based chemotherapy in postoperative CCRT. Methods. A total of 117 patients with LAHNC were enrolled between December 2007 and December 2012. Survival, compliance/adverse events, and independent prognostic factors were analyzed. Results. Median follow-up time was 30.0 (3.1–73.0) months. Most patients completed the entire course of postoperative CCRT (radiotherapy ≄ 60 Gy, 94.9%; ≄6 times weekly chemotherapy, 75.2%). Only 17.1% patients required hospital admission. The most common adverse effect was grade 3/4 mucositis (28.2%). No patient died due to protocol-related adverse effects. Multivariate analysis revealed the following independent prognostic factors: oropharyngeal cancer, extracapsular spread, and total radiation dose. Two-year progression-free survival and overall survival rates were 70.9% and 79.5%, respectively. Conclusion. Modified weekly cisplatin-based chemotherapy is an acceptable regimen in postoperative CCRT for LAHNC

    Morphological and Molecular Defects in Human Three-Dimensional Retinal Organoid Model of X-Linked Juvenile Retinoschisis

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    X-linked juvenile retinoschisis (XLRS), linked to mutations in the RS1 gene, is a degenerative retinopathy with a retinal splitting phenotype. We generated human induced pluripotent stem cells (hiPSCs) from patients to study XLRS in a 3D retinal organoid in vitro differentiation system. This model recapitulates key features of XLRS including retinal splitting, defective retinoschisin production, outer-segment defects, abnormal paxillin turnover, and impaired ER-Golgi transportation. RS1 mutation also affects the development of photoreceptor sensory cilia and results in altered expression of other retinopathy-associated genes. CRISPR/Cas9 correction of the disease-associated C625T mutation normalizes the splitting phenotype, outer-segment defects, paxillin dynamics, ciliary marker expression, and transcriptome profiles. Likewise, mutating RS1 in control hiPSCs produces the disease-associated phenotypes. Finally, we show that the C625T mutation can be repaired precisely and efficiently using a base-editing approach. Taken together, our data establish 3D organoids as a valid disease model
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