5,661 research outputs found
Information Diffusion Power of Political Party Twitter Accounts During Japan's 2017 Election
In modern election campaigns, political parties utilize social media to
advertise their policies and candidates and to communicate to electorates. In
Japan's latest general election in 2017, the 48th general election for the
Lower House, social media, especially Twitter, was actively used. In this
paper, we perform a detailed analysis of social graphs and users who retweeted
tweets of political parties during the election. Our aim is to obtain accurate
information regarding the diffusion power for each party rather than just the
number of followers. The results indicate that a user following a user who
follows a political party account tended to also follow the account. This means
that it does not increase diversity because users who follow each other tend to
share similar values. We also find that followers of a specific party
frequently retweeted the tweets. However, since users following the user who
follow a political party account are not diverse, political parties delivered
the information only to a few political detachment users.Comment: The 10th International Conference on Social Informatics (SocInfo
2018
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Robust and stable transcriptional repression in Giardia using CRISPRi.
Giardia lamblia is a binucleate protistan parasite causing significant diarrheal disease worldwide. An inability to target Cas9 to both nuclei, combined with the lack of nonhomologous end joining and markers for positive selection, has stalled the adaptation of CRISPR/Cas9-mediated genetic tools for this widespread parasite. CRISPR interference (CRISPRi) is a modification of the CRISPR/Cas9 system that directs catalytically inactive Cas9 (dCas9) to target loci for stable transcriptional repression. Using a Giardia nuclear localization signal to target dCas9 to both nuclei, we developed efficient and stable CRISPRi-mediated transcriptional repression of exogenous and endogenous genes in Giardia. Specifically, CRISPRi knockdown of kinesin-2a and kinesin-13 causes severe flagellar length defects that mirror defects with morpholino knockdown. Knockdown of the ventral disk MBP protein also causes severe structural defects that are highly prevalent and persist in the population more than 5 d longer than defects associated with transient morpholino-based knockdown. By expressing two guide RNAs in tandem to simultaneously knock down kinesin-13 and MBP, we created a stable dual knockdown strain with both flagellar length and disk defects. The efficiency and simplicity of CRISPRi in polyploid Giardia allows rapid evaluation of knockdown phenotypes and highlights the utility of CRISPRi for emerging model systems
A study of the combustion chemistry of petroleum and bio-fuel oil asphaltenes
The combustion of heavy fuel oils such as Bunker C and vacuum residual oil (VRO) are widely used for industrial applications such as furnaces, power generation and for large marine engines. There is also the possible use of bio-oils derived from biomass. Combustion of these oils generates carbonaceous particulate emissions and polynuclear aromatic hydrocarbons (PAH) that are both health hazards and have an adverse effect on the climate. This paper explores the mechanism of the formation of fine particulate soot and cenospheres. The chemical structure of petroleum asphaltene have been investigated via pyrolysis techniques. The results are consistent with a structure made up of linked small aromatic and naphthenic clusters with substituent alkyl groups, some in the long chains, with the building blocks held together by bridging groups. Other functional groups also play a role. The corresponding bio-asphaltene is made up of similar aromatic and oxygenated species and behave in an analogous way
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Disrupted iron regulation in the brain and periphery in cocaine addiction
Stimulant drugs acutely increase dopamine neurotransmission in the brain, and chronic use leads to neuroadaptive changes in the mesolimbic dopamine system and morphological changes in basal ganglia structures. Little is known about the mechanisms underlying these changes but preclinical evidence suggests that iron, a coenzyme in dopamine synthesis and storage, may be a candidate mediator. Iron is present in high concentrations in the basal ganglia and stimulant drugs may interfere with iron homeostasis. We hypothesised that morphological brain changes in cocaine addiction relate to abnormal iron regulation in the brain and periphery. We determined iron concentration in the brain, using quantitative susceptibility mapping, and in the periphery, using iron markers in circulating blood, in 44 patients with cocaine addiction and 44 healthy controls. Cocaine-addicted individuals showed excess iron accumulation in the globus pallidus, which strongly correlated with duration of cocaine use, and mild iron deficiency in the periphery, which was associated with low iron levels in the red nucleus. Our findings show that iron dysregulation occurs in cocaine addiction and suggest that it arises consequent to chronic cocaine use. Putamen enlargement in these individuals was unrelated to iron concentrations, suggesting that these are co-occurring morphological changes that may respectively reflect predisposition to, and consequences of cocaine addiction. Understanding the mechanisms by which cocaine affects iron metabolism may reveal novel therapeutic targets, and determine the value of iron levels in the brain and periphery as biomarkers of vulnerability to, as well as progression and response to treatment of cocaine addiction.This work was supported by the NIHR Cambridge Biomedical Research Centre and the Behavioural and Clinical Neuroscience Institute (which was supported by a joint award from the Medical Research Council and the Wellcome Trust). The Food Frequency Questionnaire and related analysis software were used in the study. These instruments were initially developed as part of the EPIC-Norfolk Study, which was supported by Cancer Research UK programme grant (C864/A8257)
In the face of threat: neural and endocrine correlates of impaired facial emotion recognition in cocaine dependence.
The ability to recognize facial expressions of emotion in others is a cornerstone of human interaction. Selective impairments in the recognition of facial expressions of fear have frequently been reported in chronic cocaine users, but the nature of these impairments remains poorly understood. We used the multivariate method of partial least squares and structural magnetic resonance imaging to identify gray matter brain networks that underlie facial affect processing in both cocaine-dependent (n = 29) and healthy male volunteers (n = 29). We hypothesized that disruptions in neuroendocrine function in cocaine-dependent individuals would explain their impairments in fear recognition by modulating the relationship with the underlying gray matter networks. We found that cocaine-dependent individuals not only exhibited significant impairments in the recognition of fear, but also for facial expressions of anger. Although recognition accuracy of threatening expressions co-varied in all participants with distinctive gray matter networks implicated in fear and anger processing, in cocaine users it was less well predicted by these networks than in controls. The weaker brain-behavior relationships for threat processing were also mediated by distinctly different factors. Fear recognition impairments were influenced by variations in intelligence levels, whereas anger recognition impairments were associated with comorbid opiate dependence and related reduction in testosterone levels. We also observed an inverse relationship between testosterone levels and the duration of crack and opiate use. Our data provide novel insight into the neurobiological basis of abnormal threat processing in cocaine dependence, which may shed light on new opportunities facilitating the psychosocial integration of these patients.This work was funded by a research grant from the Medical Research Council (G0701497) and supported by the infrastructure of the Behavioural and Clinical Neuroscience Institute (which is supported by a joint award from the Medical Research Council and the Wellcome Trust).
This study was jointly sponsored by the Cambridge University Hospitals NHS Foundation Trust and the University of Cambridge. KD Ersche, CC Hagan, and PS Jones are supported by the Medical Research Council, and DG Smith by the Cambridge Overseas Trust.This is the final version of the article. It first appeared from NPG via http://dx.doi.org/10.1038/tp.2015.5
Stump-harvesting for bioenergy probably has transient impacts on abundance, richness and community structure of beetle assemblages
Harvesting of tree stumps for bioenergy is popular and, although the environmental impact has been considered with respect to ecosystem processes, there have been fewer studies on the impact of stump-harvesting on biodiversity. We carried out pitfall-trap surveys of beetle communities at eight plots across four sites (four plots were clear-fells where stumps remained and four were clear-fells where stumps were harvested). Initially, we recovered 7743 beetles when stumps were extracted but still on site (Year 1). All beetles were identified to family level and ground beetles and wood-associated beetles to species level. One year after stumps were extracted, the survey was repeated. In this collection, 2898 individual beetles were recovered. In Year 1, stump-harvesting had a negative impact on beetle abundance and richness. However, 1year after stumps were removed, there were no significant differences in these variables at any site. At the community level, stump-harvesting weakly but significantly, affected carabid composition. Oneyear after stumps were removed, stump-harvesting had no effect on community composition. Stump-harvesting initially negatively affects beetle abundance, family-richness and carabid species richness, as well as community structure, although any effects are not large, are site-specific and are probably not persistent. © 2017 The Royal Entomological Societ
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