111 research outputs found

    Political Speech on Twitter: A Sentiment Analysis of Tweets and News Coverage of Local Gun Policy

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    While the gun debate has been one of America’s most politically contentious issues, Twitter has become, in recent years a popular venue for politicians to carry out the debate. The present thesis is aimed at better understanding of political speech on Twitter, as well as the ways in which political frames and sentiment on Twitter differ from those of news media coverage regarding gun policy in the state of Arkansas. The study uses framing theory, which assumes that both news media and individuals use frames to construct perceptions and narratives about issues. Adopting an automated content analysis as a method, the study examined 354 gun-related tweets downloaded from the Twitter accounts of three Arkansas politicians (Charlie Collins, Denise Garner, and Greg Leding) and 40 news articles about gun policy involving these politicians from three local newspapers. The results indicated that state politicians’ discourse on Twitter constituted of a variety of extremely polarized words and frames pertaining and appealing to the core values of their local constituents, while local newspapers’ frames were very fact-based and unbiased. The results also showed that political sentiment on Twitter was extremely negative, fearful, and agitated, while news media expressed a very neutral sentiment in their coverage of gun policy, suggesting a new venue for further investigation of current assumptions about the negative nature of news tone

    FE-SEM Characterization of Some Nanomaterial

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    Enjeux et impacts des barrages de Diama (Mauritanie) et Arzal (France) : des contextes socio-économiques et environnementaux différents pour de mêmes conséquences

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    The similar dams of Arzal (Vilaine, France) and Diama (Mauritania-Senegal frontier) have same strategic functions for the regions and countries where they are built as fresh waters storage. They also had similar consequences over the ecosystems and local and regional activities. The imperfect results of the belated remediations also had as disastrous induced effects and leave the populations and ecosystems in a fragile and vulnerable situation if confronted with any environmental (drought, flood…), socio-economical or political (relations between Mauritania and Senegal) crisis

    Size effect on magnetism of Fe thin films in Fe/Ir superlattices

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    In ferromagnetic thin films, the Curie temperature variation with the thickness is always considered as continuous when the thickness is varied from nn to n+1n+1 atomic planes. We show that it is not the case for Fe in Fe/Ir superlattices. For an integer number of atomic planes, a unique magnetic transition is observed by susceptibility measurements, whereas two magnetic transitions are observed for fractional numbers of planes. This behavior is attributed to successive transitions of areas with nn and n+1n+1 atomic planes, for which the TcT_c's are not the same. Indeed, the magnetic correlation length is presumably shorter than the average size of the terraces. Monte carlo simulations are performed to support this explanation.Comment: LaTeX file with Revtex, 5 pages, 5 eps figures, to appear in Phys. Rev. Let

    Experimental and modeling analysis of p-type Bi0.4Sb1.6Te3 and graphene nanocomposites

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    The state-of-the-art Bismuth-Telluride (Bi2Te3) based systems are promising thermoelectric materials for efficient thermoelectric applications. In this study, the effect of graphene nanosheets (GNS) integrity on thermoelectric properties of a p-type Bi0.4Sb1.6Te3 alloy has been studied using high-energy ball milling and SPS sintering techniques. The synthesized pristine Bi0.4Sb1.6Te3 and 0.05wt% GNS/Bi0.4Sb1.6Te3 nanocomposites at different addition times of GNS have exhibited a single-phase and artifact-free bulk nanocrystalline Bi0.4Sb1.6Te3 with nanocrystals size of 17 nm. The TEM analysis confirmed the mechanical exfoliation of graphene filler in 5m nanocomposite into a single-layered nanostructure with an interplanar spacing of 0.343 nm. The prominent Raman features of the monolayered graphene sheet have appeared in the synthesized 5m-GNS/Bi0.4Sb1.6Te3 nanocomposite. This highlighted the crucial rule of graphene addition time on its structure and morphology of the synthesized nanocomposites. The ZT profile of 5m nanocomposite reached 0.801 at 348 K till 398 K. This resulted in 65% of improvements to the pristine Bi0.4Sb1.6Te3 pellet at 323 K. The obtained results were used to simulate a thermoelectric (TE) device module using ANSYS Workbench. The GNS nanocomposites have shown an ultrahigh output power of 95.57 W compared to 89.96 W for the pristine module at ΔT of 150 °C. The GNS addition has increased the output power of pristine Bi0.4Sb1.6Te3 by 7%, leading to comparable TE performance to other simulated Bi2Te3 systems

    Raman scattering reveals strong LO-phonon-hole-plasmon coupling in nominally undoped GaAsBi: optical determination of carrier concentration

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    We report room-temperature Raman scattering studies of nominally undoped (100) GaAs1−xBix epitaxial layers exhibiting Biinduced (p-type) longitudinal-optical-plasmon coupled (LOPC) modes for 0.018≤x≤0.048. Redshifts in the GaAs-like optical modes due to alloying are evaluated and are paralleled by strong damping of the LOPC. The relative integrated Raman intensities of LO(Γ) and LOPC ALO/ALOPC are characteristic of heavily doped p-GaAs, with a remarkable near total screening of the LO(Γ) phonon (ALO/ALOPC →0) for larger Bi concentrations. A method of spectral analysis is set out which yields estimates of hole concentrations in excess of 5 × 1017 cm−3 and correlates with the Bi molar fraction. These findings are in general agreement with recent electrical transport measurements performed on the alloy, and while the absolute size of the hole concentrations differ, likely origins for the discrepancy are discussed. We conclude that the damped LO-phonon-hole-plasmon coupling phenomena plays a dominant role in Raman scattering from unpassivated nominally undoped GaAsBi

    The Effect of Senegal River Irrigation Water Quality on Soil Salinization: A Study of the Main Canal of the M’Pourie Plain in Mauritania

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    In this study, the Senegal River, being the main source of water, plays a crucial role in the area’s agricultural development. Irrigation on the M’Pourie plain using water from the Senegal River is carried out without any prior sanitation control. An evaluation of the quality of irrigation water and its impact on soil salinization in different agricultural plots soil salinity is crucial for the effective utilization of traditional irrigation water over extended periods. Comprehensive physico-chemical analyses were conducted across nine locations on the M’Pourie plain in Rosso during the dynamic seasons of 2021-2023. Nevertheless, a relatively small number of studies have employed soil salinity indexing methods to examine the consequences of river irrigation on soil salinity. The analysis and interpretation of the results obtained were based both on classic methods (average and correlations) and more advanced techniques such as principal component analysis (PCA) and the Piper diagram which allow characterization and a spatial typology of water. Analysis of the Piper diagram highlights the distinction between two groups of water, weakly and moderately mineralized, ranging from 52.22 μS.cm-1 in the dry season to 72.22 μS.cm-1 in the rainy season, presenting a sodium-potassium bicarbonate facies The variability of irrigation water supplies, proves to be important in the functioning of an agro-systems. Two modes of operation have become individualized: the dry phase mode, characterized by very strong mineralization of the water linked to a significant load of dissolved elements, and the wet phase mode, whose water quality is poorly mineralized but shows the impact that its irrigation water can represent in the loading of organic and mineral pollution and the need for strict control of these waters upstream before their agricultural use. The results of this study show the absence of risks of soil salinization in relation to the chemical nature of irrigation water and the impact of agriculture on the M’Pourie plain

    Cross-cultural comparison of mental illness stigma and help-seeking attitudes: a multinational population-based study from 16 Arab countries and 10,036 individuals

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    BackgroundThere is evidence that culture deeply affects beliefs about mental illnesses\u27 causes, treatment, and help-seeking. We aimed to explore and compare knowledge, attitudes toward mental illness and help-seeking, causal attributions, and help-seeking recommendations for mental illnesses across various Arab countries and investigate factors related to attitudes toward help-seeking.MethodsWe carried out a multinational cross-sectional study using online self-administered surveys in the Arabic language from June to November 2021 across 16 Arab countries among participants from the general public.ResultsMore than one in four individuals exhibited stigmatizing attitudes towards mental illness (26.5%), had poor knowledge (31.7%), and hold negative attitudes toward help-seeking (28.0%). ANOVA tests revealed a significant difference between countries regarding attitudes (F = 194.8, p \u3c .001), knowledge (F = 88.7, p \u3c .001), and help-seeking attitudes (F = 32.4, p \u3c .001). Three multivariate regression analysis models were performed for overall sample, as well as Palestinian and Sudanese samples that displayed the lowest and highest ATSPPH-SF scores, respectively. In the overall sample, being female, older, having higher knowledge and more positive attitudes toward mental illness, and endorsing biomedical and psychosocial causations were associated with more favorable help-seeking attitudes; whereas having a family psychiatric history and endorsing religious/supernatural causations were associated with more negative help-seeking attitudes. The same results have been found in the Palestinian sample, while only stigma dimensions helped predict help-seeking attitudes in Sudanese participants.ConclusionInterventions aiming at improving help-seeking attitudes and behaviors and promoting early access to care need to be culturally tailored, and congruent with public beliefs about mental illnesses and their causations
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