2,179 research outputs found

    Information sources cited and relayed in political conversations on Twitter

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    Using the Twitter data collected prior to the Presidential Election in Korea in 2012, we ask questions regarding influential sources of information in public political discourse. The frequently cited sources, being included as URLs in political tweet messages, are identified and categorized. The result shows that people rely on various sources of information beyond the traditional news media, but the pattern of sharing differ by sources

    The Effect of Nanocrystalline Cellulose (NCC) Filler on Polylactic Acid (PLA) Nanocomposite Properties

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    This paper discusses the effect of nanocrystalline cellulose (NCC) when used as filler on polylactic acid (PLA)-based nanocomposites and on its mechanical properties and permeability. NCC was produced from commercial cellulose and another cellulose source, i.e. oil palm empty fruit bunch, by hydrolysis of microcrystalline cellulose with sulphuric acid and by oxidation with ammonium persulfate. The nanocomposites were made by adding nanocrystalline cellulose with varying compositions into PLA. A solvent casting method was used to produce a nanocomposite film with 5% v/v triacetin as a coupling agent. Both methods produced crystalline celluloses within the micro and nano range with mean particle size at 99.5 nm and 157.9 nm for the sulphuric acid hydrolysis and the ammonium persulfate oxidation method, respectively. The utilization of NCC as PLA composite filler increased the percentage of elongation at break with a highest percentage 19.02% for addition of 1% NCC filler. However, higher compositions of cellulosic filler resulted in a decreasing trend of tensile strength and elongation at break. Higher content of NCC filler in the PLA matrix increased the nanocomposite's water vapor permeability

    Mysterious Influential Users in Political Communication on Twitter: Users' Occupation Information and Its Impact on Retweetability

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    This study attempts to examine the effect of userā€™s self-disclosed identification to measure his influence and activity on Twitter. By looking at the most frequently shared top 1076 tweets written by 250 users during the 2012 presidential election campaign South Korea, we particularly examine the relation between userā€™s occupation information and the measures of his ā€˜influenceā€™: the number of followers and number of retweets by others. Influential users in South Korean political communication network on Twitter are classified as one group with self-disclosed occupation information and the other group without that information. Userā€™s occupation information clearly shows the impact on the number of followers for both groups. On the other hand, user group without self-disclosed occupation information has a higher level of producing influential political tweets and wide retweetability over the other group, regardless the small number of followers. It suggests that further study needs to identify other variables that may influence particular user or tweetā€™s retweetability as an indicator of influence.ye

    Green's function approach to transport through a gate-all-around Si nanowire under impurity scattering

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    We investigate transport properties of gate-all-around Si nanowires using non-equilibrium Green's function technique. By taking into account of the ionized impurity scattering we calculate Green's functions self-consistently and examine the effects of ionized impurity scattering on electron densities and currents. For nano-scale Si wires, it is found that, due to the impurity scattering, the local density of state profiles loose it's interference oscillations as well as is broaden and shifted. In addition, the impurity scattering gives rise to a different transconductance as functions of temperature and impurity scattering strength when compared with the transconductance without impurity scattering.Comment: 8 pages, 4 figure

    Current and noise expressions for radio-frequency single-electron transistors

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    We derive self-consistent expressions of current and noise for single-electron transistors driven by time-dependent perturbations. We take into account effects of the electrical environment, higher-order co-tunneling, and time-dependent perturbations under the two-charged state approximation using the Schwinger-Kedysh approach combined with the generating functional technique. For a given generating functional, we derive exact expressions for tunneling currents and noises and present the forms in terms of transport coefficients. It is also shown that in the adiabatic limit our results encompass previous formulas. In order to reveal effects missing in static cases, we apply the derived results to simulate realized radio-frequency single-electron transistor. It is found that photon-assisted tunneling affects largely the performance of the single-electron transistor by enhancing both responses to gate charges and current noises. On various tunneling resistances and frequencies of microwaves, the dependence of the charge sensitivity is also discussed.Comment: 18 pages, 9 figure

    Veganomics: Current Status and Challenges

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    Products introduced as vegan are recognized by consumers as ethical consumption that protects animals and the environment, so they are becoming a trend in recent marketing strategies. However, consumers are confused by the claim that veganism consumption is not environmentally friendly, contrary to consumers' perception of animal protection and environmental protection. Vegan leather, which appeared as an alternative to natural leather, emits harmful substances during the manufacturing and disposal process, is less durable than natural leather, and has a shorter lifespan, resulting in a problem of fast fashion. Substitute meat is emerging as a food of the future due to environmental problems caused by raising livestock. However, considerable carbon is generated during the production of substitute meat, and there is a problem in verifying the safety of fiber materials such as various additives used during the production process. In the case of vegan cosmetics, they use only eco-friendly ingredients derived from nature instead of animal ingredients and do not test on animals, so the impact on the environment is minimal. Overall, bigonomics products generate relatively less environmental pollutants and cause less environmental pollution, but there are still limitations to be overcome. It is thought that the limitations of bigonomics can be overcome through social collective practice such as education and investment in parallel with individual practice in daily life. Furthermore, I think that if there is a correct understanding of vegannomics and communication about its value, the vegan industry will be able to take its place as a major industry in society. In this review, the current status of bigonomics in the food, cosmetics, and fashion industries, which are being developed by consumers' ethical consumption, is reviewed and prospects are presented. This review will help set the direction in each industry pursuing vigenomics

    Functional Benefit after Modification of Radial Forearm Free Flap for Soft Palate Reconstruction

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    ObjectivesTo compare the velopharyngeal function, swallowing and speech of the conventional and modified radial forearm free flap (RFFF) for soft palate reconstruction.MethodsRetrospective clinical study. Twenty-eight patients who underwent oropharyngeal reconstruction with RFFF were divided into two groups: 10 patients had conventional folded RFFF and 18 patients underwent modified method.ResultsThe average speech intelligibility score in modified RFFF group was 8.0Ā±2.4, and 6.2Ā±2.2 in conventional RFFF group (P<0.05). The nasalance was 27.4Ā±7.8% in modified group and 38.6Ā±2.7% in conventional group during no nasal passage reading and 43.6Ā±7.3% in modified group, 55.2Ā±7.6% in conventional group during high nasal passage reading (P<0.05). The subjective swallowing functional score was 2.8 in modified group and 2.1 in conventional group.ConclusionThe speech assessment and nasalance demonstrate a more favorable outcome in modified group than conventional group

    Lateral resistance of mass timber shear wall connected by withdrawal-type connectors

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    In this study, the lateral resistances of mass timber shear walls were investigated for seismic design. The lateral resistances were predicted by kinematic models with mechanical properties of connectors, and compared with experimental data. Four out of 7 shear wall specimens consisted of a single Ply-lam panel and withdrawal-type connectors. Three out of 7 shear wall specimens consisted of two panels made by dividing a single panel in half. The divided panels were connected by 2 or 4 connectors like a single panel before being divided. The applied vertical load was 0, 24, or 120 kN, and the number of connectors for connecting the Ply-lam wall-to-floor was 2 or 4. As a result, the tested data were 6.3 to 52.7% higher than the predicted value by kinematic models, and it means that the lateral resistance can be designed by the behavior of the connector, and the prediction will be safe. The effects of wall-to-wall connectors, wall-to-floor connectors and vertical loads on the shear wall were analyzed with the experimental data.This project was funded by the Korea Forest Service (Korea Forestry Promotion Institute) and the Ministry of Land, Infrastructure and Transport (the Korea Agency for Infrastructure Technology Advancement)

    Who Are Less Likely to Receive Subsequent Chemotherapy Beyond First-Line Therapy for Advanced Non-small Cell Lung Cancer?: Implications for Selection of Patients for Maintenance Therapy

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    BackgroundProspective studies have implied that maintenance therapy for non-small cell lung cancer (NSCLC) has its effect by giving active drugs earlier to patients who otherwise die without receiving second-line therapy. The purpose of this study was to select patients with NSCLC who could most benefit from maintenance therapy, by evaluating which patients would be less likely to receive second-line therapy.MethodsClinicopathologic data of patients with advanced NSCLC who received four cycles of first-line chemotherapy followed by time-off therapy and eventual disease progression or death were reviewed retrospectively. Patients were grouped into ones with first-line therapy only or ones with more than first-line therapy. Clinical characteristics between the two groups were compared.ResultsA total of 271 patients were eligible for analysis, and 39 patients (14.4%) received only first-line therapy. Patients significantly more likely to receive only first-line therapy had performance status of two or three after first-line therapy, large volume of initial target lesions (sum of long diameters ā‰„70 mm), or smaller decrease in target lesions (decrease <20%) after first-line therapy. Median overall survival of the 143 patients (52.8%) with at least one of these characteristics (16.3 months) was significantly shorter than that of patients without any of these characteristics (23.5 months, p = 0.007).ConclusionMaintenance therapy may be of greater benefit to patients with NSCLC who have clinical characteristics including poor performance status after first-line therapy, large initial target lesions, or smaller decrease in target lesions after first-line therapy

    Sensitivity of censored data analysis to determine the characteristic value of structural timber

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    In structural timber tests, unintended failure mechanisms occur frequently in specimens and their results are called censored data. There are two censored data analysis: censored maximum likelihood estimation (CMLE) and Kaplanā€“Meier (KM) method. In this study, the precision of the censored data analysis was investigated to determine the characteristic value, 5th percentile value, of the structural timber. The results show that (1) the 5th percentile value was underestimated by ordinary data analysis methods; maximum likelihood estimation (MLE) and Order statistics. (2) CMLE with 30% lower tail censored data and KM method provided much more precise 5th percentile value. (3) The amount of under-measurement (5Ā MPa, 10Ā MPa, and 15Ā MPa in this simulation study) did not show significant effect on the 5th percentile determination in CMLE and KM method, but the proportion of censored data (percentage of unintended failure specimen; 10%, 20%, 30%, and 40%) affected the determination of 5th percentile value. (4) CMLE with 30% lower tail censored data and KM method showed good agreement in case that the data included unintended failure data up to 20%.(1) This work was supported by Research Resettlement Fund for the new facā€‘ulty of Seoul National University. (2) This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2017R1A2B1010748)
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