2,067 research outputs found
Explaining Political Violence Against Civilians in Northern Ireland: A Contention-Oriented Approach
In contrast to prevalent theories of terrorism, this study develops a contention-oriented approach where levels and forms of political violence against civilians depend upon: (1) the strategies of combatants; (2) the means of contention; (3) the locations of allies and opponents; (4) the collective identities of combatants; and (5) the dynamics of contention, including whether or not representatives of paramilitary organizations are included in formal peace processes. Quantitative analyses of a multi-source database of civilian deaths taking place in Northern Ireland between 1966 and 2006 offer preliminary support for this approach. The study underscores the insights provided by theories and methods used in the fields of social movements research and peace and conflict studies
Grasping the Intentions of Others: The Perceived Intentionality of an Action Influences Activity in the Superior Temporal Sulcus during Social Perception
An explication of the neural substrates for social perception is an important component in the emerging field of social cognitive neuroscience and is relevant to the field of cognitive neuroscience as a whole. Prior studies from our laboratory have demonstrated that passive viewing of biological motion (Pelphrey, Mitchell, et al., 2003; Puce et al., 1998) activates the posterior superior temporal sulcus (STS ) region. Furthermore, recent evidence has shown that the perceived context of observed gaze shifts (Pelphrey, Singerman, et al., 2003; Pelphrey et al., 2004) modulates STS activity. Here, using event-related functional magnetic resonance imaging at 4 T, we investigated brain activity in response to passive viewing of goal- and nongoal-directed reaching-to-grasp movements. Participants viewed an animated character making reaching-to-grasp movements either toward (correct) or away (incorrect) from a blinking dial. Both conditions evoked significant posterior STS activity that was strongly right lateralized. By examining the time course of the blood oxygenation level-dependent response from areas of activation, we observed a functional dissociation. Incorrect trials evoked significantly greater activity in the STS than did correct trials, while an area posterior and inferior to the STS (likely corresponding to the MT/ V5 complex) responded equally to correct and incorrect movements. Parietal cortical regions, including the superior parietal lobule and the anterior intraparietal sulcus, also responded equally to correct and incorrect movements, but showed evidence for differential responding based on the hand and arm (left or right) of the animated character used to make the reaching-to-grasp movement. The results of this study further suggest that a region of the right posterior STS is involved in analyzing the intentions of other people's actions and that activity in this region is sensitive to the context of observed biological motions
Market for Luca Pacioli\u27s Summa Arithmetica
This paper looks at an aspect of Luca Pacioli and his Summa Arithmetica that has not previously been explored in detail the market for which he wrote the book. In order to do so, it follows a path identified by two clues in the bookkeeping treatise as to the nature of this market that modern eyes, unaware of how life was in late 15th century Italy, have missed. After discussing the curriculum taught in schools at that time, this paper considers a range of possible markets for which the book may have been written. The paper concludes that it was written primarily for, and sold mainly to, merchants who used the book as a reference text, as a source of pleasure from the mathematical puzzles it contained, and as an aid for the education of their sons
Models of the ICM with Heating and Cooling: Explaining the Global and Structural X-ray Properties of Clusters
(Abridged) Theoretical models that include only gravitationally-driven
processes fail to match the observed mean X-ray properties of clusters. As a
result, there has recently been increased interest in models in which either
radiative cooling or entropy injection play a central role in mediating the
properties of the intracluster medium. Both sets of models give reasonable fits
to the mean properties of clusters, but cooling only models result in fractions
of cold baryons in excess of observationally established limits and the
simplest entropy injection models do not treat the "cooling core" structure
present in many clusters and cannot account for entropy profiles revealed by
recent X-ray observations. We consider models that marry radiative cooling with
entropy injection, and confront model predictions for the global and structural
properties of massive clusters with the latest X-ray data. The models
successfully and simultaneously reproduce the observed L-T and L-M relations,
yield detailed entropy, surface brightness, and temperature profiles in
excellent agreement with observations, and predict a cooled gas fraction that
is consistent with observational constraints. The model also provides a
possible explanation for the significant intrinsic scatter present in the L-T
and L-M relations and provides a natural way of distinguishing between clusters
classically identified as "cooling flow" clusters and dynamically relaxed
"non-cooling flow" clusters. The former correspond to systems that had only
mild levels (< 300 keV cm^2) of entropy injection, while the latter are
identified as systems that had much higher entropy injection. This is borne out
by the entropy profiles derived from Chandra and XMM-Newton.Comment: 20 pages, 15 figures, accepted for publication in the Astrophysical
Journa
Recommended from our members
Residues From Coal Conversion and Utilization: Advanced Mineralogical Characterization and Disposed Byproduct Diagenesis
The goals of the project are two-fold: 1) to upgrade semi-quantitative X-ray diffraction(QXRD) methods presently used in analyzing complex coal combustion by-product (CCB)systems, with the quantitative Rietveld method, and 2) to apply this method to a set of by-product materials that have been disposed or utilized for a long period (5 years or more) in contact with the natural environment, to further study the nature of CCB diagenesis. The project is organized into three tasks to accomplish these two goals: 1) thorough characterization of a set of previously analyzed disposed by-product materials, 2) development of a set of CCB specific protocols for Rietveld QXRD, and 3) characterization of an additional set of disposed CCB materials, including application of the protocols for Rietveld QXRD developed in Task 2
Face-Specific Resting Functional Connectivity between the Fusiform Gyrus and Posterior Superior Temporal Sulcus
Faces activate specific brain regions in fMRI, including the fusiform gyrus (FG) and the posterior superior temporal sulcus (pSTS). The fact that the FG and pSTS are frequently co-activated suggests that they may interact synergistically in a distributed face processing network. Alternatively, the functions implemented by these regions may be encapsulated from each other. It has proven difficult to evaluate these two accounts during visual processing of face stimuli. However, if the FG and pSTS interact during face processing, the substrate for such interactions may be apparent in a correlation of the BOLD timeseries from these two regions during periods of rest when no faces are present. To examine face-specific resting correlations, we developed a new partial functional connectivity approach in which we removed variance from the FG that was shared with other category-selective and control regions. The remaining face-specific FG resting variance was then used to predict resting signals throughout the brain. In two experiments, we observed face-specific resting functional connectivity between FG and pSTS, and importantly, these correlations overlapped precisely with the face-specific pSTS region obtained from independent localizer runs. Additional region-of-interest and pattern analyses confirmed that the FGâpSTS resting correlations were face-specific. These findings support a model in which face processing is distributed among a finite number of connected, but nevertheless face-specialized regions. The discovery of category-specific interactions in the absence of visual input suggests that resting networks may provide a latent foundation for task processing
Views from the coalface: chemo-sensors, sensor networks and the semantic sensor web
Currently millions of sensors are being deployed in sensor networks across the world. These networks generate vast quantities of heterogeneous data across various levels of spatial and temporal granularity. Sensors range from single-point in situ sensors to remote satellite sensors which can cover the globe. The semantic sensor web in principle should allow for the unification of the web with the real-word. In this position paper, we discuss the major challenges to this unification from the perspective of sensor developers (especially chemo-sensors) and integrating sensors data in real-world deployments. These challenges include: (1) identifying the quality of the data; (2) heterogeneity of data sources and data transport methods; (3) integrating data streams from different sources and modalities (esp. contextual information), and (4) pushing intelligence to the sensor level
PTFE mapping in gas diffusion media for PEMFCs using fluorescence microscopy
Differentiating between the various polytetrafluoroethylene based structures inside polymer electrolyte membrane fuel cells with a degree of certainty is necessary to optimize manufacturing processes and to investigate possible degradation mechanisms. We have developed a novel method using fluorescence microscopy for distinguishing the origin and location of PTFE and/or NafionÂź in Membrane Electrode assemblies and the gas diffusion media from different sources and stages of processing. Fluorescent material was successfully diffused into the PTFE based structures in the GDM by addition to the âinkâ precursor for both the microporous layer and the catalyst layer; this made it possible to map separately both layers in a way that has not been reported before. It was found that hot pressing of membrane coated structures resulted in physical dispersion of those layers away from the membrane into the GDM itself. This fluorescence technique should be of interest to membrane electrode assembly manufacturers and fuel cell developers and could be used to track the degradation of different PTFE structures independently in the future
- âŠ