189 research outputs found

    Analysis on Factors of Forgetting and Three Ways for Effective Memory

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    Psychologists often attribute the term 'memory' to the retention of information like knowledge or experience. This paper focuses on the reason why not only older people but also the younger generation have been reported that they often forget about certain things that happened before or not happened yet. This paper includes the methods of comparing several data from different studies and citing many conclusions in other studies. This paper presents current knowledge about how and why people usually forget. The conclusion I draw from this whole process of writing is that the factors such as the aging, stress and emotion, encoding failure, storage failure, and the retrieval failure can influence differently on the retain of the memory. But, still, we have some solutions to do our utmost in reducing their effects

    TheImpact of Dams on Sediment Transport from the Parker River Watershed to the Plum Island Estuary:

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    Thesis advisor: Noah P. SnyderThough previous studies have shown saltmarsh adaptability to some degree of sea-level rise (SLR), sediment supply is critical to sustaining saltmarshes as SLR accelerates. Land-use activities, such as dams, often influence watershed sediment transport and delivery to the coast. Previous studies have suggested that, even in small watersheds, dams can significantly impact coastal sediment budgets. The Parker River watershed (PRW) in northeastern Massachusetts hosts 20 dams and several natural lakes, and drains into the Plum Island Sound Estuary (PIE). This research aims to evaluate the impact of dams and sediment transport in the PRW. Three approaches were used: theoretical modeling of sediment transport patterns using digital elevation models; spatial analysis of suspended sediment concentration (SSC) and remote sensing data; and empirical calculations of reservoir trap efficiency. Geomorphic modeling indicates that bankfull discharge can transport 20 μm grains (silt) as wash load throughout the PRW. Sediment deposition might happen at Crane Pond and in reservoirs, but removing dams would not change this pattern. Both SSC data and observations of satellite images during high-flow events indicate low supply and transport of sediment throughout the PRW. The estimates of sediment yield (Y) are low for the PRW. An empirical calculation indicates little-to-no trap efficiencies for all dams. Therefore, fluvial contribution to the sediment budget of the PIS estuary is limited and dam removals in the PRW are unlikely to change the rate of sediment delivery to the PIE. The proposed method of this study provides an additional scope to assess the ecological benefits of removing a dam and could be easily replicated for other locations for similar assessment. Future studies should assess sediment dynamics and management practices from a more thorough perspective incorporating the riverine, estuarine and shelf system.Thesis (MS) — Boston College, 2020.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Earth and Environmental Sciences

    Modeling rules of regional flash flood susceptibility prediction using different machine learning models

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    The prediction performance of several machine learning models for regional flash flood susceptibility is characterized by variability and regionality. Four typical machine learning models, including multilayer perceptron (MLP), logistic regression (LR), support vector machine (SVM), and random forest (RF), are proposed to carry out flash flood susceptibility modeling in order to investigate the modeling rules of different machine learning models in predicting flash flood susceptibility. The original data of 14 environmental factors, such as elevation, slope, aspect, gully density, and highway density, are chosen as input variables for the MLP, LR, SVM, and RF models in order to estimate and map the distribution of the flash flood susceptibility index in Longnan County, Jiangxi Province, China. Finally, the prediction performance of various models and modeling rules is evaluated using the ROC curve and the susceptibility index distribution features. The findings show that: 1) Machine learning models can accurately assess the region’s vulnerability to flash floods. The MLP, LR, SVM, and RF models all predict susceptibility very well. 2) The MLP (AUC=0.973, MV=0.1017, SD=0.2627) model has the best prediction performance for flash flood susceptibility, followed by the SVM (AUC=0.964, MV=0.1090, SD=0.2561) and RF (AUC=0.975, MV=0.2041, SD=0.1943) models, and the LR (AUC=0.882, MV=0.2613, SD=0.2913) model. 3) To a large extent, environmental factors such as elevation, gully density, and population density influence flash flood susceptibility

    Single-nucleus RNA-seq identifies divergent populations of FSHD2 myotube nuclei.

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    FSHD is characterized by the misexpression of DUX4 in skeletal muscle. Although DUX4 upregulation is thought to be the pathogenic cause of FSHD, DUX4 is lowly expressed in patient samples, and analysis of the consequences of DUX4 expression has largely relied on artificial overexpression. To better understand the native expression profile of DUX4 and its targets, we performed bulk RNA-seq on a 6-day differentiation time-course in primary FSHD2 patient myoblasts. We identify a set of 54 genes upregulated in FSHD2 cells, termed FSHD-induced genes. Using single-cell and single-nucleus RNA-seq on myoblasts and differentiated myotubes, respectively, we captured, for the first time, DUX4 expressed at the single-nucleus level in a native state. We identified two populations of FSHD myotube nuclei based on low or high enrichment of DUX4 and FSHD-induced genes ("FSHD-Lo" and "FSHD Hi", respectively). FSHD-Hi myotube nuclei coexpress multiple DUX4 target genes including DUXA, LEUTX and ZSCAN4, and also upregulate cell cycle-related genes with significant enrichment of E2F target genes and p53 signaling activation. We found more FSHD-Hi nuclei than DUX4-positive nuclei, and confirmed with in situ RNA/protein detection that DUX4 transcribed in only one or two nuclei is sufficient for DUX4 protein to activate target genes across multiple nuclei within the same myotube. DUXA (the DUX4 paralog) is more widely expressed than DUX4, and depletion of DUXA suppressed the expression of LEUTX and ZSCAN4 in late, but not early, differentiation. The results suggest that the DUXA can take over the role of DUX4 to maintain target gene expression. These results provide a possible explanation as to why it is easier to detect DUX4 target genes than DUX4 itself in patient cells and raise the possibility of a self-sustaining network of gene dysregulation triggered by the limited DUX4 expression

    Characterization and cytotoxicity of PAHs in PM2.5 emitted from residential solid fuel burning in the Guanzhong Plain, China

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    The emission factors (EFs) of polycyclic aromatic hydrocarbons (PAHs) in PM2.5 were measured from commonly used stoves and fuels in the rural Guanzhong Plain, China. The toxicity of the PM2.5 also was measured using in vitro cellular tests. EFs of PAHs varied from 0.18 mg kg(-1) (maize straw charcoal burning in a clean stove) to 83.3 mg kg(-1) (maize straw burning in Heated Kang). The two largest influencing factors on PAH EFs were air supply and volatile matter proportion in fuel. Improvements in these two factors could decrease not only EFs of PAHs but also the proportion of 3-ring to 5-ring PAHs. Exposure to PM2.5 extracts caused a concentration-dependent decline in cell viability but an increase in reactive oxygen species (ROS), tumor necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6). PM2.5 emitted from maize burning in Heated Kang showed the highest cytotoxicity, and EFs of ROS and inflammatory factors were the highest as well. In comparison, maize straw charcoal burning in a clean stove showed the lowest cytotoxicity, which indicated a clean stove and fuel treatment were both efficient methods for reducing cytotoxicity of primary PM2.5. The production of these bioreactive factors were highly correlated with 3-ring and 4-ring PAHs. Specifically, pyrene, anthracene and benzo(a)anthracene had the highest correlations with ROS production (R = 0.85, 0.81 and 0.80, respectively). This study shows that all tested stoves emitted PM2.5 that was cytotoxic to human cells; thus, there may be no safe levels of exposure to PM2,5 emissions from cooking and heating stoves using solid fuels. The study may also provide a new approach for evaluating the cytotoxicity of primary emitted PM2.5 from solid fuel burning as well as other PM2.5 sources. (C) 2018 Elsevier Ltd. All rights reserved

    Integrative analysis and identification of key elements and pathways regulated by Traditional Chinese Medicine (Yiqi Sanjie formula) in colorectal cancer

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    Introduction: The clinical efficacy of Yiqi Sanjie (YQSJ) formula in the treatment of stage III colorectal cancer (CRC) has been demonstrated. However, the underlying antitumor mechanisms remain poorly understood.Materials and methods: The aim of the present study was to comprehensively characterize the molecular and microbiota changes in colon tissues and fecal samples from CRC mice and in CRC cell lines treated with YQSJ or its main active component, peiminine. Integrative tandem mass tag-based proteomics and ultra-performance liquid chromatography coupled with time-of-flight tandem mass spectrometry metabolomics were used to analyze azoxymethane/dextran sulfate sodium-induced CRC mouse colon tissues.Results: The results showed that 0.8% (57/7568) of all detected tissue proteins and 3.2% (37/1141) of all detected tissue metabolites were significantly changed by YQSJ treatment, with enrichment in ten and six pathways associated with colon proteins and metabolites, respectively. The enriched pathways were related to inflammation, sphingolipid metabolism, and cholesterol metabolism. Metabolomics analysis of fecal samples from YQSJ-treated mice identified 121 altered fecal metabolites and seven enriched pathways including protein digestion and absorption pathway. 16S rRNA sequencing analysis of fecal samples indicated that YQSJ restored the CRC mouse microbiota structure by increasing the levels of beneficial bacteria such as Ruminococcus_1 and Prevotellaceae_UCG_001. In HCT-116 cells treated with peiminine, data-independent acquisition-based proteomics analysis showed that 1073 of the 7152 identified proteins were significantly altered and involved in 33 pathways including DNA damage repair, ferroptosis, and TGF-β signaling.Conclusion: The present study identified key regulatory elements (proteins/metabolites/bacteria) and pathways involved in the antitumor mechanisms of YQSJ, suggesting new potential therapeutic targets in CRC

    Eficacia de la magnetoterápia en la consolidación de fracturas óseas. Revisión sistemática.

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    El trabajo de fin de grado realizado consiste en una revisión sistemática, tratando de al eficacia del aparato de magnetoterapia en relación a la consolidación ósea cualidad y tiempo. Para ello se utilizaron las bases de datos PubMed, ENFISPO, PEDro, la Biblioteca Cochrane de estudios publicados entre el periodo de año 2010 y 2015. Los resultados en relación a la consolidación ósea, ninguno de los tres artículos seleccionados obtuvimos resultados significativos. Aunque las pruebas de laboratorios disponibles indican que la estimulación con campos electromagnéticos puede ofrecer algún beneficio en la consolidación de fracturas óseas, a la hora de aplicarlo en seres humanos como posible tratamiento no es concluyente o suficiente para informar de su utilización en la práctica actual. Las conclusiones y resultados más definitivos o positivos, recomendando su utilización sobre el efecto en el tratamiento aguardan ensayos controlados aleatorios adicionales bien realizados
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