431 research outputs found

    A STUDY OF THE IMPACT OF A CROWD WISDOM ONLINE LEARNING COMMUNITY PLATFORM ON STUDENT LEARNING

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    The use of collective intelligence applications in educational settings has been reported in the literature for almost two decades. These collective intelligence applications aggregate individual knowledge via different synchronous and asynchronous mode of communications and Web 2.0 applications which support learning, communication and collaboration activities, and create “Wisdom of the Crowds”. Crowdsourcing further extends these collective intelligence processes in a distributed and crossorganizational way. This paper evaluates the effects and impacts of crowd wisdom applications on a peer assisted learning support service titled Peer-Assisted Learning scheme using Supplemental Instruction (PALSI) in a higher education institution in Hong Kong. Adopting the Design Science approach, an Online Learning Community (OLC) platform was developed tap on the Wisdom of Crowds and its effectiveness on student learning was evaluated. The OLC platform is not designed to replace existing face-to-face PALSI learning sessions and activities. Rather it helps to provide an additional online platform for supplementing and facilitating interaction between student mentors and mentees and among student mentees as well. The OLC platform is designed in a way that supports indexed and search functions who join the PALSI scheme, and it can also be archived as a repository for future reference by similar courses. Empirical analysis was carried out to evaluate the relationship between user participation and assessment results. Statistics show that students who made use of the OLC platform obtained better grades

    Overview of Some Intelligent Control Structures and Dedicated Algorithms

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    Automatic control refers to the use of a control device to make the controlled object automatically run or keep the state unchanged without the participation of people. The guiding ideology of intelligent control is based on people’s way of thinking and ability to solve problems, in order to solve the current methods that require human intelligence. We already know that the complexity of the controlled object includes model uncertainty, high nonlinearity, distributed sensors/actuators, dynamic mutations, multiple time scales, complex information patterns, big data process, and strict characteristic indicators, etc. In addition, the complexity of the environment manifests itself in uncertainty and uncertainty of change. Based on this, various researches continue to suggest that the main methods of intelligent control can include expert control, fuzzy control, neural network control, hierarchical intelligent control, anthropomorphic intelligent control, integrated intelligent control, combined intelligent control, chaos control, wavelet theory, etc. However, it is difficult to want all the intelligent control methods in a chapter, so this chapter focuses on intelligent control based on fuzzy logic, intelligent control based on neural network, expert control and human-like intelligent control, and hierarchical intelligent control and learning control, and provide relevant and useful programming for readers to practice

    Chameleon: Plug-and-Play Compositional Reasoning with Large Language Models

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    Large language models (LLMs) have achieved remarkable progress in various natural language processing tasks with emergent abilities. However, they face inherent limitations, such as an inability to access up-to-date information, utilize external tools, or perform precise mathematical reasoning. In this paper, we introduce Chameleon, a plug-and-play compositional reasoning framework that augments LLMs to help address these challenges. Chameleon synthesizes programs to compose various tools, including LLM models, off-the-shelf vision models, web search engines, Python functions, and rule-based modules tailored to user interests. Built on top of an LLM as a natural language planner, Chameleon infers the appropriate sequence of tools to compose and execute in order to generate a final response. We showcase the adaptability and effectiveness of Chameleon on two tasks: ScienceQA and TabMWP. Notably, Chameleon with GPT-4 achieves an 86.54% accuracy on ScienceQA, significantly improving upon the best published few-shot model by 11.37%; using GPT-4 as the underlying LLM, Chameleon achieves a 17.8% increase over the state-of-the-art model, leading to a 98.78% overall accuracy on TabMWP. Further studies suggest that using GPT-4 as a planner exhibits more consistent and rational tool selection and is able to infer potential constraints given the instructions, compared to other LLMs like ChatGPT.Comment: 25 pages, 10 figures. Project page: https://chameleon-llm.github.i

    A Novel Selective JAK2 Inhibitor Identified Using Pharmacological Interactions

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    The JAK2/STAT signaling pathway mediates cytokine receptor signals that are involved in cell growth, survival and homeostasis. JAK2 is a member of the Janus kinase (JAK) family and aberrant JAK2/STAT is involved with various diseases, making the pathway a therapeutic target. The similarity between the ATP binding site of protein kinases has made development of specific inhibitors difficult. Current JAK2 inhibitors are not selective and produce unwanted side effects. It is thought that increasing selectivity of kinase inhibitors may reduce the side effects seen with current treatment options. Thus, there is a great need for a selective JAK inhibitor. In this study, we identified a JAK2 specific inhibitor. We first identified key pharmacological interactions in the JAK2 binding site by analyzing known JAK2 inhibitors. Then, we performed structure-based virtual screening and filtered compounds based on their pharmacological interactions and identified compound NSC13626 as a potential JAK2 inhibitor. Results of enzymatic assays revealed that against a panel of kinases, compound NSC13626 is a JAK2 inhibitor and has high selectivity toward the JAK2 and JAK3 isozymes. Our cellular assays revealed that compound NSC13626 inhibits colorectal cancer cell (CRC) growth by downregulating phosphorylation of STAT3 and arresting the cell cycle in the S phase. Thus, we believe that compound NSC13626 has potential to be further optimized as a selective JAK2 drug

    Estrogens in municipal wastewater and receiving waters in the Beijing-Tianjin-Hebei region, China:Occurrence and risk assessment of mixtures

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    The potentially high release of estrogens to surface waters due to high population density and local livestock production in the Beijing-Tianjin-Hebei region may pose adverse effects on reproductive systems of aquatic organisms. This study found that total measured concentrations of estrone (E1), 17β-estradiol (E2), estriol (E3), 17α-ethinylestradiol (EE2) and diethylstilbestrol (DES) were 468 ± 27 ng/L in treated wastewater and 219 ± 23 ng/L in river waters in this region. E2, E3 and EE2 were the predominant estrogens in river waters. The restriction of DES for human use should have been enforced, however concentrations of DES were relatively high compared to other studies. Haihe and Yongdingxin Rivers delivered approximately 1.8 tonnes of estrogens to the Bohai Bay annually. Concentrations of individual estrogens were significantly higher in river waters in the dry season, however, mass loadings were significantly higher in the wet season. The average E2-equivalent concentrations reached 1.2 ± 0.2 and 0.64 ± 0.08 μg-E2/L following long-term and short-term exposure estimates, respectively, in river waters with an EE2 contribution of over 90 %. This could give rise to high risks to fish. Estrogens in river waters largely derived from human excretion. Field studies on estrogenic effects on fish reproductive systems are required locally considering high estrogen contamination levels

    The occurrence of home and personal care products in the Haihe River catchment and estimation of human exposure

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    A sub-catchment of the Haihe River basin goes through the Beijing-Tianjin region with a population of 26 million, therefore, the use and release of home and personal care product ingredients (HPCPs) to the river catchment could be potentially substantial. Many HPCPs have been shown to be toxic to human and animals. So, it is essential to know the exposure level of HPCPs in the river basin. The average concentrations of five preservatives, three disinfectants and an antioxidant were found to be 398, 352 and 77.7 ng L−1, respectively, in the dry season. The chemical concentrations in the effluents of wastewater treatment plants (WWTPs) and untreated wastewater discharge were respectively ca. 1.3–2.2 and 1.6–7.5 times higher than those in river water. The mass flux of ∑HPCPs has been estimated to be 8.7 g/h at the outfall of the Shahe Reservoir and 181 g/h and 214 g/h at the estuary of the Haihe River and Yongdingxin River to Bohai Bay, respectively. The attenuation of ∑HPCPs was over 79% along the Wenyu River. By using the backward method, the estimated average loadings to WWTPs ranged from 0.51 to 2.0 mg/day/cap for the various individual compounds. They were 1–3 orders of magnitude higher than the estimation from the forward calculation for parabens. This indicates the possible underestimation of chemical usage and human exposure levels by the current published studies or the probably additional industrial release to the target catchment. Such a study provides useful information for the development of chemical management approaches and indicates that further research is needed to improve the estimation of HPCPs usage and emissions to aquatic environment

    Microcrystalline-Silicon-Oxide-Based N-Type Reflector Structure in Micromorph Tandem Solar Cells

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    N-type microcrystalline silicon oxide thin films (n-c-SiO:H) have been deposited by VHF-PECVD (40 MHz) with reactant gas mixtures of CO2/SiH4 and H2. N-c-SiO thin films exhibiting low refractive index value (n600nm∼2), and medium/high conductivity (≧10−9 S/cm) are suitable to be used as an “n-type reflector” in micromorph tandem solar cells. Transmission electron microscopy (TEM) results show that microstructures of n-c-SiO:H thin films contain nanocrystalline Si particles, which are randomly embedded in the a-SiO matrix. This specific microstructure provides n-c-SiO:H thin films excellent optoelectronic properties; therefore, n-c-SiO:H thin films are appropriate candidates for “n-type reflector” structures in Si tandem solar cells

    Breast Cancer Cells Induce Cancer-Associated Fibroblasts to Secrete Hepatocyte Growth Factor to Enhance Breast Tumorigenesis

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    It has been well documented that microenvironment consisting of stroma affects breast cancer progression. However, the mechanisms by which cancer cells and fibroblasts, the major cell type in stroma, interact with each other during tumor development remains to be elucidated. Here, we show that the human cancer-associated fibroblasts (CAFs) had higher activity in enhancing breast tumorigenecity compared to the normal tissue-associated fibroblasts (NAFs) isolated from the same patients. The expression level of hepatocyte growth factor (HGF) in these fibroblasts was positively correlated with their ability to enhance breast tumorigenesis in mice. Deprivation of HGF using a neutralizing antibody reduced CAF-mediated colony formation of human breast cancer cells, indicating that CAFs enhanced cancer cell colony formation mainly through HGF secretion. Co-culture with human breast cancer MDA-MB-468 cells in a transwell system enhanced NAFs to secret HGF as well as promote tumorigenecity. The newly gained ability of these “educated” NAFs became irreversible after continuing this process till fourth passage. These results suggested that breast cancer cells could alter the nature of its surrounding fibroblasts to secrete HGF to support its own progression through paracrine signaling

    Spironolactone Lowers Portal Hypertension by Inhibiting Liver Fibrosis, ROCK-2 Activity and Activating NO/PKG Pathway in the Bile-Duct-Ligated Rat

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    OBJECTIVE: Aldosterone, one of the main peptides in renin angiotensin aldosterone system (RAAS), has been suggested to mediate liver fibrosis and portal hypertension. Spironolactone, an aldosterone antagonist, has beneficial effect on hyperdynamic circulation in clinical practice. However, the mechanisms remain unclear. The present study aimed to investigate the role of spionolactone on liver cirrhosis and portal hypertension. METHODS: Liver cirrhosis was induced by bile duct ligation (BDL). Spironolactone was administered orally (20 mg/kg/d) after bile duct ligation was performed. Liver fibrosis was assessed by histology, Masson's trichrome staining, and the measurement of hydroxyproline and type I collagen content. The activation of HSC was determined by analysis of alpha smooth muscle actin (α-SMA) expression. Protein expressions and protein phosphorylation were determined by immunohistochemical staining and Western blot analysis, Messenger RNA levels by quantitative real time polymerase chain reaction (Q-PCR). Portal pressure and intrahepatic resistance were examined in vivo. RESULTS: Treatment with spironolactone significantly lowered portal pressure. This was associated with attenuation of liver fibrosis, intrahepatic resistance and inhibition of HSC activation. In BDL rat liver, spironolactone suppressed up-regulation of proinflammatory cytokines (TNFα and IL-6). Additionally, spironolactone significantly decreased ROCK-2 activity without affecting expression of RhoA and Ras. Moreover, spironolactone markedly increased the levels of endothelial nitric oxide synthase (eNOS), phosphorylated eNOS and the activity of NO effector-protein kinase G (PKG) in the liver. CONCLUSION: Spironolactone lowers portal hypertension by improvement of liver fibrosis and inhibition of intrahepatic vasoconstriction via down-regulating ROCK-2 activity and activating NO/PKG pathway. Thus, early spironolactone therapy might be the optional therapy in cirrhosis and portal hypertension
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