Showing 1191 - 1200 of 2039 Items
Varieties of digital authoritarianism analyzing Russia’s approach to internet governance
Date: 2021-12-01
Creator: Laura Howells
Laura A. Henry
Access: Open access
- Digital authoritarianism threatens the privacy and rights of Internet users worldwide, yet scholarship on this topic remains limited in analytical power and case selection. In this article, we introduce a comprehensive analytical framework to the field of Internet governance and apply it first, briefly, to the well-known case of China and then, in more depth, to the still-understudied Russian case. We identify the extent and relative centralization of Internet governance as well as proactive versus reactive approaches to governance as notable differences between the cases, highlighting variation among digital authoritarians’ governance strategies. We conclude that Russia’s Internet governance model is less comprehensive and consistent than China’s, but its components may be more easily exported to other political systems. We then consider whether recent changes to Russia’s Internet governance suggest that it could converge with the Chinese model over time.
Saving our marine archives
Date: 2017-01-01
Creator: Emilie Dassié
Kristine Delong
Hali Kilbourne
Branwen Williams
Nerilie, Abram
Logan Brenner
Chloé Brahmi
Kim M. Cobb
Thierry Corrège
Delphine Dissard
Julien Emile-Geay
Heitor Evangelista
Michael N. Evans
Jesse Farmer
Thomas Felis
Michael Gagan
David P. Gillikin
Nathalie Goodkin
Myriam Khodri
Ana Carolina Lavagnino
Michèle Lavigne
Claire Lazareth
Braddock Linsley
Janice Lough
Helen McGregor
Intan S. Nurhati
Gilman Ouellette
Laura Perrin
Maureen Raymo
Brad Rosenheim
Michael Sandstrom
Bernd R. Schöne
Access: Open access
Assessing longitudinal pathways between maternal depressive symptoms, parenting self-esteem and infant temperament
Date: 2019-08-01
Creator: Lea Takács
Filip Smolík
Samuel Putnam
Access: Open access
- Background Previous studies of relations between parenting self-concepts, parental adjustment and child temperament have been ambiguous regarding the direction of influence; and have rarely followed families from pregnancy through the first year of life. The current study examines change and stability in maternal depressive symptoms, parenting competences and child temperament through the perinatal period until nine months postpartum. Methods Czech mothers (N = 282) participated at three time points: the third trimester of pregnancy (Time 1), six weeks (Time 2) and nine months postpartum (Time 3). Questionnaire data concerned depressive symptoms (T1, T2, T3), maternal parenting self-esteem (T1, T2) and sense of competence (T3), and child temperament (T2, T3). A path model was used to examine concurrent and longitudinal relations between these variables. Results The analyses indicated longitudinal stability of all constructs, as well as concurrent relations between them. Longitudinal relations supported child-to-parent, rather than parent-to-child, effects: child difficult temperament predicted decreases in perceived maternal parenting competences, but maternal variables did not predict change in infant temperament. In addition, we observed weak mutual relations between maternal depression levels and parenting competences, such that maternal depression diminished perceived parenting competences that in turn contributed to higher levels of depression. Conclusion Mothers’ confidence in their ability to parent is influenced by their experience with a difficult infant and by their depressive symptoms during the child’s first year of life. Depressive symptoms are, in turn, aggravated by mothers’ low perceived competences in the parenting role.
Cells and constructible representations in type B
Date: 2008-10-13
Creator: Thomas Pietraho
Access: Open access
- We examine the partition of a finite Coxeter group of type B into cells determined by a weight function L. The main objective of these notes is to reconcile Lusztig's description of constructible representations in this setting with conjectured combinatorial descriptions of cells.
Subleading-color contributions to gluon-gluon scattering in N = 4 SYM theory and relations to N = 8 supergravity
Date: 2008-11-01
Creator: Stephen G. Naculich
Horatiu Nastase
Howard J. Schnitzer
Access: Open access
- We study the subleading-color (nonplanar) contributions to the four-gluon scattering amplitudes in = 4 supersymmetric SU(N) Yang-Mills theory. Using the formalisms of Catani and of Sterman and Tejeda-Yeomans, we develop explicit expressions for the infrared-divergent contributions of all the subleading-color L-loop amplitudes up to three loops, and make some conjectures for the IR behavior for arbitrary L. We also derive several intriguing relations between the subleading-color one- and two-loop four-gluon amplitudes and the four-graviton amplitudes of = 8 supergravity. The exact one- and two-loop = 8 supergravity amplitudes can be expressed in terms of the one- and two-loop N-independent = 4 SYM amplitudes respectively, but the natural generalization to higher loops fails, despite having a simple interpretation in terms of the 't Hooft picture. We also find that, at least through two loops, the subleading-color amplitudes of = 4 SYM theory have uniform transcendentality (as do the leading-color amplitudes). Moreover, the = 4 SYM Catani operators, which express the IR-divergent contributions of loop amplitudes in terms of lower-loop amplitudes, are also shown to have uniform transcendentality, and to be the maximum transcendentality piece of the QCD Catani operators. © SISSA 2008.
An information theoretical approach to task-switching: Evidence from cognitive brain potentials in humans
Date: 2008-03-28
Creator: Francisco Barceló
José A. Periáñez
Erika Nyhus
Access: Open access
- This study aimed to clarify the neural substrates of behavioral switch and restart costs in intermittently instructed task-switching paradigms. Event-related potentials (ERPs) were recorded while participants were intermittently cued to switch or repeat their categorization rule (Switch task), or else they performed two perceptually identical control conditions (NoGo and Oddball). The three tasks involved different task-sets with distinct stimulus-response associations in each, but identical visual stimulation, consisting of frequent colored shapes (p = 0.9) and randomly interspersed infrequent black shapes (p = 0.1; '+' and 'x' symbols). Behavioral restart costs were observed in the first target responses following all black shapes in the Switch and NoGo tasks - but not in the Oddball task - and corresponded with enhanced fronto-centrally distributed early cue-locked P3 activity (peak latency 325-375 ms post-cue onset at the vertex). In turn, behavioral switch costs were associated with larger late cue-locked P3 amplitudes in the Switch task only (peak latency 400-450 ms post-cue onset at mid-parietal sites). Together with our information theoretical estimations, ERP results suggested that restart and switch costs indexed two neural mechanisms related to the preparatory resolution of uncertainty: (1) the intermittent re-activation of task-set information, and (2) the updating of stimulus-response mappings within an active task set, as indexed by early and late cue-locked P3 activations, respectively. In contrast, target-locked P3 activations reflected a functionally distinct mechanism related to the implementation of task-set information. We conclude that task-switching costs consist of both switch-specific and switch-unspecific processes during the preparation and execution stages of task performance. © 2008 Barceló, Periáñez and Nyhus.
Transvection-based gene regulation in Drosophila is a complex and plastic trait
Date: 2014-01-01
Creator: Xinyang Bing
Teresa Z. Rzezniczak
Jack R. Bateman
Thomas J.S. Merritt
Access: Open access
- Transvection, a chromosome pairing-dependent form of trans-based gene regulation, is potentially widespread in the Drosophila melanogaster genome and varies across cell types and within tissues in D. melanogaster, characteristics of a complex trait. Here, we demonstrate that the trans-interactions at the Malic enzyme (Men) locus are, in fact, transvection as classically defined and are plastic with respect to both genetic background and environment. Using chromosomal inversions, we show that trans-interactions at the Men locus are eliminated by changes in chromosomal architecture that presumably disrupt somatic pairing. We further show that the magnitude of transvection at the Men locus is modified by both genetic background and environment (temperature), demonstrating that transvection is a plastic phenotype. Our results suggest that transvection effects in D. melanogaster are shaped by a dynamic interplay between environment and genetic background. Interestingly, we find that cis-based regulation of the Men gene is more robust to genetic background and environment than trans-based. Finally, we begin to uncover the nonlocal factors that may contribute to variation in transvection overall, implicating Abd-B in the regulation of Men in cis and in trans in an allele-specific and tissue-specific manner, driven by differences in expression of the two genes across genetic backgrounds and environmental conditions.
Rapid oligo-galacturonide induced changes in protein phosphorylation in arabidopsis
Date: 2016-04-01
Creator: Bruce D. Kohorn
Divya Hoon
Benjamin B. Minkoff
Michael R. Sussman
Susan L., Kohorn
Access: Open access
- The wall-associated kinases (WAKs)1 are receptor protein kinases that bind to long polymers of cross-linked pectin in the cell wall. These plasma-membrane-associated protein kinases also bind soluble pectin fragments called oligo-galacturonides (OGs) released from the wall after pathogen attack and damage. WAKs are required for cell expansion during development but bind water soluble OGs generated from walls with a higher affinity than the wall-associated polysaccharides. OGs activate a WAKdependent, distinct stress-like response pathway to help plants resist pathogen attack. In this report, a quantitative mass-spectrometric-based phosphoproteomic analysis was used to identify Arabidopsis cellular events rapidly induced by OGs in planta. Using N14/ N15 isotopic in vivo metabolic labeling, we screened 1,000 phosphoproteins for rapid OG-induced changes and found 50 proteins with increased phosphorylation, while there were none that decreased significantly. Seven of the phosphosites within these proteins overlap with those altered by another signaling molecule plants use to indicate the presence of pathogens (the bacterial "elicitor" peptide Flg22), indicating distinct but overlapping pathways activated by these two types of chemicals. Genetic analysis of genes encoding 10 OG-specific and two Flg22/OG-induced phosphoproteins reveals that null mutations in eight proteins compromise the OG response. These phosphorylated proteins with genetic evidence supporting their role in the OG response include two cytoplasmic kinases, two membrane-associated scaffold proteins, a phospholipase C, a CDPK, an unknown cadmium response protein, and a motor protein. Null mutants in two proteins, the putative scaffold protein REM1.3, and a cytoplasmic receptor like kinase ROG2, enhance and suppress, respectively, a dominant WAK allele. Altogether, the results of these chemical and genetic experiments reveal the identity of several phosphorylated proteins involved in the kinase/ phosphatase-mediated signaling pathway initiated by cell wall changes.
Cell wall-associated kinases and pectin perception
Date: 2016-01-01
Creator: Bruce D. Kohorn
Access: Open access
- The pectin matrix of the angiosperm cell wall is regulated in both synthesis and modification and greatly influences the direction and extent of cell growth. Pathogens, herbivory and mechanical stresses all influence this pectin matrix and consequently plant form and function. The cell wall-associated kinases (WAKs) bind to pectin and regulate cell expansion or stress responses depending upon the state of the pectin. This review explores the WAKs in the context of cell wall biology and signal transduction pathways.
The cell wall-associated kinases, WAKs, as pectin receptors
Date: 2012-05-08
Creator: Bruce D. Kohorn
Susan L. Kohorn
Access: Open access
- The wall-associated kinases, WAKs, are encoded by five highly similar genes clustered in a 30-kb locus in Arabidopsis. These receptor-like proteins contain a cytoplasmic serine threonine kinase, a transmembrane domain, and a less conserved region that is bound to the cell wall and contains a series of epidermal growth factor repeats. Evidence is emerging that WAKs serve as pectin receptors, for both short oligogalacturonic acid fragments generated during pathogen exposure or wounding, and for longer pectins resident in native cell walls. This ability to bind and respond to several types of pectins correlates with a demonstrated role for WAKs in both the pathogen response and cell expansion during plant development. © 2012 Kohorn and Kohorn.