Bots increase exposure to negative and inflammatory content in online social systems.

Abstract:

:Societies are complex systems, which tend to polarize into subgroups of individuals with dramatically opposite perspectives. This phenomenon is reflected-and often amplified-in online social networks, where, however, humans are no longer the only players and coexist alongside with social bots-that is, software-controlled accounts. Analyzing large-scale social data collected during the Catalan referendum for independence on October 1, 2017, consisting of nearly 4 millions Twitter posts generated by almost 1 million users, we identify the two polarized groups of Independentists and Constitutionalists and quantify the structural and emotional roles played by social bots. We show that bots act from peripheral areas of the social system to target influential humans of both groups, bombarding Independentists with violent contents, increasing their exposure to negative and inflammatory narratives, and exacerbating social conflict online. Our findings stress the importance of developing countermeasures to unmask these forms of automated social manipulation.

authors

Stella M,Ferrara E,De Domenico M

doi

10.1073/pnas.1803470115

subject

Has Abstract

pub_date

2018-12-04 00:00:00

pages

12435-12440

issue

49

eissn

0027-8424

issn

1091-6490

pii

1803470115

journal_volume

115

pub_type

杂志文章
  • Cyclic AMP-dependent plasticity underlies rapid changes in odor coding associated with reward learning.

    abstract::Learning and memory rely on dopamine and downstream cAMP-dependent plasticity across diverse organisms. Despite the central role of cAMP signaling, it is not known how cAMP-dependent plasticity drives coherent changes in neuronal physiology that encode the memory trace, or engram. In Drosophila, the mushroom body (MB)...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1709037115

    authors: Louis T,Stahl A,Boto T,Tomchik SM

    更新日期:2018-01-16 00:00:00

  • Human bone marrow and umbilical cord blood cells generate CD4+ and CD8+ single-positive T cells in murine fetal thymus organ culture.

    abstract::Murine fetal thymus lobes isolated from both normal and scid/scid mice can be colonized by donor cells from either human bone marrow or human umbilical cord blood in vitro. Subsequent organ culture results in a transient production of a few CD4+ CD8+ (double-positive) cells and then the accumulation of CD4+ or CD8+ (s...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.90.22.10778

    authors: Yeoman H,Gress RE,Bare CV,Leary AG,Boyse EA,Bard J,Shultz LD,Harris DT,DeLuca D

    更新日期:1993-11-15 00:00:00

  • Synthesis of bioactive protein hydrogels by genetically encoded SpyTag-SpyCatcher chemistry.

    abstract::Protein-based hydrogels have emerged as promising alternatives to synthetic hydrogels for biomedical applications, owing to the precise control of structure and function enabled by protein engineering. Nevertheless, strategies for assembling 3D molecular networks that carry the biological information encoded in full-l...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1401291111

    authors: Sun F,Zhang WB,Mahdavi A,Arnold FH,Tirrell DA

    更新日期:2014-08-05 00:00:00

  • Modulation of NKG2D, NKp46, and Ly49C/I facilitates natural killer cell-mediated control of lung cancer.

    abstract::Natural killer (NK) cells play a critical role in controlling malignancies. Susceptibility or resistance to lung cancer, for example, specifically depends on NK cell function. Nevertheless, intrinsic factors that control NK cell-mediated clearance of lung cancer are unknown. Here we report that NK cells exposed to exo...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1804931115

    authors: Shi L,Li K,Guo Y,Banerjee A,Wang Q,Lorenz UM,Parlak M,Sullivan LC,Onyema OO,Arefanian S,Stelow EB,Brautigan DL,Bullock TNJ,Brown MG,Krupnick AS

    更新日期:2018-11-13 00:00:00

  • Locus coeruleus toggles reciprocal prefrontal firing to reinstate fear.

    abstract::The medial prefrontal cortex (mPFC) plays an essential role in regulating emotion, including inhibiting fear when danger has passed. The extinction of fear, however, is labile and a number of factors, including stress, cause extinguished fear to relapse. Here we show that fear relapse in rats limits single-unit activi...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1814278116

    authors: Giustino TF,Fitzgerald PJ,Ressler RL,Maren S

    更新日期:2019-04-23 00:00:00

  • Negative selection on human genes underlying inborn errors depends on disease outcome and both the mode and mechanism of inheritance.

    abstract::Genetic variants underlying life-threatening diseases, being unlikely to be transmitted to the next generation, are gradually and selectively eliminated from the population through negative selection. We study the determinants of this evolutionary process in human genes underlying monogenic diseases by comparing vario...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.2001248118

    authors: Rapaport F,Boisson B,Gregor A,Béziat V,Boisson-Dupuis S,Bustamante J,Jouanguy E,Puel A,Rosain J,Zhang Q,Zhang SY,Gleeson JG,Quintana-Murci L,Casanova JL,Abel L,Patin E

    更新日期:2021-01-19 00:00:00

  • Changes produced by bound tryptophan in the ribosome peptidyl transferase center in response to TnaC, a nascent leader peptide.

    abstract::Studies in vitro have established that free tryptophan induces tna operon expression by binding to the ribosome that has just completed synthesis of TnaC-tRNA(Pro), the peptidyl-tRNA precursor of the leader peptide of this operon. Tryptophan acts by inhibiting Release Factor 2-mediated cleavage of this peptidyl-tRNA a...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.0600082103

    authors: Cruz-Vera LR,Gong M,Yanofsky C

    更新日期:2006-03-07 00:00:00

  • Transcriptional response to stress in the dynamic chromatin environment of cycling and mitotic cells.

    abstract::Heat shock factors (HSFs) are the master regulators of transcription under protein-damaging conditions, acting in an environment where the overall transcription is silenced. We determined the genomewide transcriptional program that is rapidly provoked by HSF1 and HSF2 under acute stress in human cells. Our results rev...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1305275110

    authors: Vihervaara A,Sergelius C,Vasara J,Blom MA,Elsing AN,Roos-Mattjus P,Sistonen L

    更新日期:2013-09-03 00:00:00

  • The delivery of copper for thylakoid import observed by NMR.

    abstract::The thylakoid compartments of plant chloroplasts are a vital destination for copper. Copper is needed to form holo-plastocyanin, which must shuttle electrons between photosystems to convert light into biologically useful chemical energy. Copper can bind tightly to proteins, so it has been hypothesized that copper part...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.0600142103

    authors: Banci L,Bertini I,Ciofi-Baffoni S,Kandias NG,Robinson NJ,Spyroulias GA,Su XC,Tottey S,Vanarotti M

    更新日期:2006-05-30 00:00:00

  • A position 12-activated H-ras oncogene in all HS578T mammary carcinosarcoma cells but not normal mammary cells of the same patient.

    abstract::Among 21 human mammary tumors analyzed for transforming genes by transfection of NIH/3T3 cells, only DNA of a carcinosarcoma cell line, HS578T, registered as positive. A Harvey (H)-ras oncogene identified in this line was cloned in biologically active form and the activating lesion was identified as a single nucleotid...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.81.17.5384

    authors: Kraus MH,Yuasa Y,Aaronson SA

    更新日期:1984-09-01 00:00:00

  • Corn pollen deposition on milkweeds in and near cornfields.

    abstract::The density of corn pollen on leaves of milkweed plants inside and outside of cornfields was measured in several studies from different localities. The purpose was to obtain a representative picture of naturally occurring pollen densities to provide a perspective for laboratory and field studies of monarch larvae feed...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.211287498

    authors: Pleasants JM,Hellmich RL,Dively GP,Sears MK,Stanley-Horn DE,Mattila HR,Foster JE,Clark P,Jones GD

    更新日期:2001-10-09 00:00:00

  • Envelope glycans of immunodeficiency virions are almost entirely oligomannose antigens.

    abstract::The envelope spike of HIV is one of the most highly N-glycosylated structures found in nature. However, despite extensive research revealing essential functional roles in infection and immune evasion, the chemical structures of the glycans on the native viral envelope glycoprotein gp120--as opposed to recombinantly ge...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1006498107

    authors: Doores KJ,Bonomelli C,Harvey DJ,Vasiljevic S,Dwek RA,Burton DR,Crispin M,Scanlan CN

    更新日期:2010-08-03 00:00:00

  • Cellular homologue (c-src) of the transforming gene of Rous sarcoma virus: isolation, mapping, and transcriptional analysis of c-src and flanking regions.

    abstract::The tumorigenic properties of Rous sarcoma virus are attributable to a 60,000-dalton protein, pp60v--src, encoded by a single viral gene, v-src. A homologous gene, c-src, that contains the information for a 60,000-dalton protein, pp60c--src, has been identified in all tested vertebrate cells. By screening a recombinan...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.78.9.5842

    authors: Parker RC,Varmus HE,Bishop JM

    更新日期:1981-09-01 00:00:00

  • Phospholipase A2 group IIA expression in gastric adenocarcinoma is associated with prolonged survival and less frequent metastasis.

    abstract::We analyzed gene expression patterns in human gastric cancers by using cDNA microarrays representing approximately equal 30,300 genes. Expression of PLA2G2A, a gene previously implicated as a modifier of the Apc(Min/+) (multiple intestinal neoplasia 1) mutant phenotype in the mouse, was significantly correlated with p...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.212646299

    authors: Leung SY,Chen X,Chu KM,Yuen ST,Mathy J,Ji J,Chan AS,Li R,Law S,Troyanskaya OG,Tu IP,Wong J,So S,Botstein D,Brown PO

    更新日期:2002-12-10 00:00:00

  • Contributions of cell kill and posttreatment tumor growth rates to the repopulation of intracerebral 9L tumors after chemotherapy: an MRI study.

    abstract::The drought of progress in clinical brain tumor therapy provides an impetus for developing new treatments as well as methods for testing therapeutics in animal models. The inability of traditional assays to simultaneously measure tumor size, location, growth kinetics, and cell kill achieved by a treatment complicates ...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.95.12.7012

    authors: Ross BD,Zhao YJ,Neal ER,Stegman LD,Ercolani M,Ben-Yoseph O,Chenevert TL

    更新日期:1998-06-09 00:00:00

  • Multibranch activity in basal and tuft dendrites during firing of layer 5 cortical neurons in vivo.

    abstract::Layer 5 pyramidal neurons process information from multiple cortical layers to provide a major output of cortex. Because of technical limitations it has remained unclear how these cells integrate widespread synaptic inputs located in distantly separated basal and tuft dendrites. Here, we obtained in vivo two-photon ca...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1312599110

    authors: Hill DN,Varga Z,Jia H,Sakmann B,Konnerth A

    更新日期:2013-08-13 00:00:00

  • DNA replication-timing analysis of human chromosome 22 at high resolution and different developmental states.

    abstract::Duplication of the genome during the S phase of the cell cycle does not occur simultaneously; rather, different sequences are replicated at different times. The replication timing of specific sequences can change during development; however, the determinants of this dynamic process are poorly understood. To gain insig...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.0408170101

    authors: White EJ,Emanuelsson O,Scalzo D,Royce T,Kosak S,Oakeley EJ,Weissman S,Gerstein M,Groudine M,Snyder M,Schübeler D

    更新日期:2004-12-21 00:00:00

  • Niche adaptation limits bacteriophage predation of Vibrio cholerae in a nutrient-poor aquatic environment.

    abstract::Vibrio cholerae, the causative agent of cholera, has reservoirs in fresh and brackish water where it interacts with virulent bacteriophages. Phages are the most abundant biological entity on earth and coevolve with bacteria. It was reported that concentrations of phage and V. cholerae inversely correlate in aquatic re...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1810138116

    authors: Silva-Valenzuela CA,Camilli A

    更新日期:2019-01-29 00:00:00

  • Selection of unique antigenic variants of Newcastle disease virus with neutralizing monoclonal antibodies and anti-immunoglobulin.

    abstract::Monoclonal antibodies were used to isolate nonneutralizable antigenic variants in the hemagglutinin-neuraminidase glycoprotein of Newcastle disease virus. It had been found that a large percentage of virus retains infectivity despite binding neutralizing antibody. This high persistent fraction of nonneutralized virus ...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.82.20.7106

    authors: Iorio RM,Bratt MA

    更新日期:1985-10-01 00:00:00

  • Proteomic and genomic signatures of repeat instability in cancer and adjacent normal tissues.

    abstract::Repetitive sequences are hotspots of evolution at multiple levels. However, due to difficulties involved in their assembly and analysis, the role of repeats in tumor evolution is poorly understood. We developed a rigorous motif-based methodology to quantify variations in the repeat content, beyond microsatellites, in ...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1908790116

    authors: Persi E,Prandi D,Wolf YI,Pozniak Y,Barnabas GD,Levanon K,Barshack I,Barbieri C,Gasperini P,Beltran H,Faltas BM,Rubin MA,Geiger T,Koonin EV,Demichelis F,Horn D

    更新日期:2019-08-20 00:00:00

  • recF-dependent induction of recA synthesis by coumermycin, a specific inhibitor of the B subunit of DNA gyrase.

    abstract::Genetic and biochemical studies on enzymes known to be involved in regulating DNA supercoiling yield a complex spectrum of effects on the Escherichia coli SOS system. Previous studies indicated that only inhibition of DNA gyrase by antibiotics that act on the DNA gyrase A subunit results in turning on the E. coli SOS ...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.80.9.2510

    authors: Smith CL

    更新日期:1983-05-01 00:00:00

  • Open complex scrunching before nucleotide addition accounts for the unusual transcription start site of E. coli ribosomal RNA promoters.

    abstract::Most Escherichia coli promoters initiate transcription with a purine 7 or 8 nt downstream from the -10 hexamer, but some promoters, including the ribosomal RNA promoter rrnB P1, start 9 nt from the -10 element. We identified promoter and RNA polymerase determinants of this noncanonical rrnB P1 start site using biochem...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1522159113

    authors: Winkelman JT,Chandrangsu P,Ross W,Gourse RL

    更新日期:2016-03-29 00:00:00

  • Mechanism by which metabolic inhibitors depolarize cultured cardiac cells.

    abstract::To elucidate the means by which metabolic inhibition depolarizes cardiac cells, spontaneously beating chicken embryonic myocardial cell aggregates were voltage clamped during superfusion with 2,4-dinitrophenol and iodoacetic acid. In aggregates continuously clamped in the pacemaker potential range, abrupt exposure to ...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.80.12.3865

    authors: Clusin WT

    更新日期:1983-06-01 00:00:00

  • Optical imaging of the spatial distribution of beta-particles emerging from surfaces.

    abstract::The multiplication in gases of ionization electrons, by the effect of the electric fields between parallel electrodes, leads to the emission of light from the molecules excited in the avalanche process. The optical imaging of this light, with intensifiers, on charge-coupled devices permits the localization, in the gas...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.86.6.1741

    authors: Charpak G,Dominik W,Zaganidis N

    更新日期:1989-03-01 00:00:00

  • A small-molecule inhibitor of the ribonucleolytic activity of human angiogenin that possesses antitumor activity.

    abstract::The results of previous preclinical and clinical studies have identified angiogenin (ANG) as a potentially important target for anticancer therapy. Here we report the design and implementation of a high-throughput screening assay to identify small molecules that bind to the ribonucleolytic active site of ANG, which is...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.152342999

    authors: Kao RY,Jenkins JL,Olson KA,Key ME,Fett JW,Shapiro R

    更新日期:2002-07-23 00:00:00

  • VH replacement in primary immunoglobulin repertoire diversification.

    abstract::The genes encoding the variable (V) region of the B-cell antigen receptor (BCR) are assembled from V, D (diversity), and J (joining) elements through a RAG-mediated recombination process that relies on the recognition of recombination signal sequences (RSSs) flanking the individual elements. Secondary V(D)J rearrangem...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1418001112

    authors: Sun A,Novobrantseva TI,Coffre M,Hewitt SL,Jensen K,Skok JA,Rajewsky K,Koralov SB

    更新日期:2015-02-03 00:00:00

  • New approach for inhibiting Rev function and HIV-1 production using the influenza virus NS1 protein.

    abstract::The Rev protein of HIV-1, which facilitates the nuclear export of HIV-1 pre-mRNAs, has been a target for antiviral therapy. Here we describe a new strategy for inhibiting Rev function and HIV-1 replication. In contrast to previous approaches, we use a wild-type rather than a mutant Rev protein and covalently link this...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.93.17.8873

    authors: Qian XY,Chen ZY,Zhang J,Rabson AB,Krug RM

    更新日期:1996-08-20 00:00:00

  • Forest transition in Vietnam and displacement of deforestation abroad.

    abstract::In some countries across the globe, tropical forest cover is increasing. The national-scale reforestation of Vietnam since 1992 is assumed to contribute to this recovery. It is achieved, however, by the displacement of forest extraction to other countries on the order of 49 (34-70) M m(3), or approximately 39% of the ...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.0904942106

    authors: Meyfroidt P,Lambin EF

    更新日期:2009-09-22 00:00:00

  • Determining complete electron flow in the cofactor photoreduction of oxidized photolyase.

    abstract::The flavin cofactor in photoenzyme photolyase and photoreceptor cryptochrome may exist in an oxidized state and should be converted into reduced state(s) for biological functions. Such redox changes can be efficiently achieved by photoinduced electron transfer (ET) through a series of aromatic residues in the enzyme. ...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1311073110

    authors: Liu Z,Tan C,Guo X,Li J,Wang L,Sancar A,Zhong D

    更新日期:2013-08-06 00:00:00

  • Reconstitution of simian virus 40 DNA replication with purified proteins.

    abstract::Replication of plasmid DNA molecules containing the simian virus 40 (SV40) origin of DNA replication has been reconstituted with seven highly purified cellular proteins plus the SV40 large tumor (T) antigen. Initiation of DNA synthesis is absolutely dependent upon T antigen, replication protein A, and the DNA polymera...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.87.22.8692

    authors: Weinberg DH,Collins KL,Simancek P,Russo A,Wold MS,Virshup DM,Kelly TJ

    更新日期:1990-11-01 00:00:00