446 research outputs found
Resting-state connectivity and functional specialization in human medial parieto-occipital cortex
According to recent models of visuo-spatial processing, the medial parieto-occipital cortex is a crucial node of the dorsal visual stream. Evidence from neurophysiological studies in monkeys has indicated that the parieto-occipital sulcus (POS) contains three functionally and cytoarchitectonically distinct areas: the visual area V6 in the fundus of the POS, and the visuo-motor areas V6Av and V6Ad in a progressively dorsal and anterior location with respect to V6. Besides different topographical organization, cytoarchitectonics, and functional properties, these three monkey areas can also be distinguished based on their patterns of cortico-cortical connections. Thanks to wide-field retinotopic mapping, areas V6 and V6Av have been also mapped in the human brain. Here, using a combined approach of resting-state functional connectivity and task-evoked activity by fMRI, we identified a new region in the anterior POS showing a pattern of functional properties and cortical connections that suggests a homology with the monkey area V6Ad. In addition, we observed distinct patterns of cortical connections associated with the human V6 and V6Av which are remarkably consistent with those showed by the anatomical tracing studies in the corresponding monkey areas. Consistent with recent models on visuo-spatial processing, our findings demonstrate a gradient of functional specialization and cortical connections within the human POS, with more posterior regions primarily dedicated to the analysis of visual attributes useful for spatial navigation and more anterior regions primarily dedicated to analyses of spatial information relevant for goal-directed action
From Crystalline to Amorphous Germania Bilayer Films at the Atomic Scale: Preparation and Characterization
A new two-dimensional (2D) germanium dioxide film has been prepared. The film consists of interconnected germania tetrahedral units forming a bilayer structure, weakly coupled to the supporting Pt(111) metal-substrate. Density functional theory calculations predict a stable structure of 558-membered rings for germania films, while for silica films 6-membered rings are preferred. By varying the preparation conditions the degree of order in the germania films is tuned. Crystalline, intermediate ordered and purely amorphous film structures are resolved by analysing scanning tunnelling microscopy images
From Crystalline to Amorphous Germania Bilayer Films at the Atomic Scale: Preparation and Characterization
A new two-dimensional (2D) germanium dioxide film has been prepared. The film consists of interconnected germania tetrahedral units forming a bilayer structure, weakly coupled to the supporting Pt(111) metal-substrate. Density functional theory calculations predict a stable structure of 558-membered rings for germania films, while for silica films 6-membered rings are preferred. By varying the preparation conditions the degree of order in the germania films is tuned. Crystalline, intermediate ordered and purely amorphous film structures are resolved by analysing scanning tunnelling microscopy images
Decentering Media Studies, Verbing the Audience: Methodological Considerations Concerning People’s Uses of Media in Urban Space
Media studies scholars are invited today to address the pervasive mediation of contemporary cities, together with researchers from human geography, urban studies, science and technology studies, and mobility studies. Current studies of people’s uses of media in urban space, in particular, could play a central role in shedding light on the mediatedness of urban daily life. Drawing on a review of this specific strand of research within the broader field of “urban media studies,” the article argues that participation in the interdisciplinary endeavor runs the risk of being hindered by overly media-centric methodological procedures. Their restrictive implications are most problematic in the taken-for-granted employment of “urban audience” and “urban media user” as key concepts in the study of how people use media in urban space. What we propose instead is to demarcate the research object by proceeding from the primary importance of urban practices. This methodological decentering of media necessitates the “verbing” of the notion of audience, thereby shifting the research focus to the activity of “audiencing” (media-related or not) and its interrelations with other urban activities
Urban data cultures in post-socialist countries: challenges for evidence-based policy towards housing sustainability
This draft report summarises the initial results from the research project "Urban Data Cultures: Understanding Creation and Management of Housing-Related Information in Post-Communist Republics". This project seeks to better understand the how geographically-varied ‘data cultures’ (i.e. variegated representations, values, norms, epistemologies, practices, infrastructures,
standards, power structures, etc, through which data is produced and used) inform the monitoring of progress towards the UN’s Sustainable Development Goals (SDGs), particularly as they relate to urban housing. For this pilot module, the countries of Georgia, Ukraine, Albania and Kyrgyzstan have been selected as research settings. Our main methods were: in-depth interviews with officials engaged in housing policy and management at the central, regional and local levels (n=24); notes from informal conversations, workshops and visits to state departments; and an analysis of background policy reports, journalism and academic literature related to the case study countries. On the basis of this material, we explore how management styles of housing data are observably impacted in our field settings by three key dynamics: marketization/decentralization; knowledge and expertise; and the evolution of data sharing infrastructures. We then proceed to outline a five-dimensional model of 'data cultures', comprising: 'relationships between data and decision-making'; 'relationships between the data of particular public organizations and civil society'; 'systematicity of data collection'; 'attitudes towards data sharing'; and 'specialization of data-related functions'. In conclusion, we outline some preliminary recommendations
Methodological Approaches in Urban Media and Communication Research
Over the last two decades, the study of urban media and communication has witnessed an upsurge of empirical research, characterized by a plurality of methodological perspectives. In this chapter, we aim to help readers find their way through the field’s main methodological heuristics, as a way to both foster internal dialogue and offer guiding principles for urban media and communication scholars to develop their empirical research. Drawing from our previous work, we distinguish three main strands of research within urban media and communication studies: approaches that consider the city as content of communication, as a context of media engagement, and as a medium of communication
Interindividual variability in functional connectivity as long-term correlate of temporal discounting
During intertemporal choice (IT) future outcomes are usually devaluated as a function of the delay, a phenomenon known as temporal discounting (TD). Based on task-evoked activity, previous neuroimaging studies have described several networks associated with TD. However, given its relevance for several disorders, a critical challenge is to define a specific neural marker able to predict TD independently of task execution. To this aim, we used restingstate functional connectivity MRI (fcMRI) and measured TD during economic choices several months apart in 25 human subjects.We further explored the relationship between TD, impulsivity and decision uncertainty by collecting standard questionnaires on individual trait/ state differences. Our findings indicate that fcMRI within and between critical nodes of taskevoked neural networks associated with TD correlates with discounting behavior measured a long time afterwards, independently of impulsivity. Importantly, the nodes form an intrinsic circuit that might support all the mechanisms underlying TD, from the representation of subjective value to choice selection through modulatory effects of cognitive control and episodic prospection
Going About the City: Methods and Methodologies for Urban Communication Research—Introduction
This introduction to the special section on methods and methodologies for urban communication research discusses major approaches to conceptualizing and researching the relationship between cities and communication. We underline the increasing significance of scholarship on the various ways in which city dwellers relate to each other and their urban environment through symbolic, technological, and material means. We then argue that a systematic conversation on the methodological principles, protocols, and practices that set apart this burgeoning area of inquiry is not only timely, but also much needed. With this objective in mind, we invited a group of scholars to reflect on the key questions, instruments, challenges, and contributions of documentary, audiencing, material, visual, mixed-method, ecological, and applied perspectives on urban communication. Based on the seven articles included in the special section, we propose three distinct but interrelated conceptual heuristics—the city as context, the city as medium, the city as content—that highlight the importance of cities as both producers and products of particular practices, interactions, and narratives. We finally conclude that, vis-à-vis research on the automatic production of urban space, urban communication scholarship may contribute to strengthening a broader research agenda rooted in an understanding of communication as a human endeavor
Formation of Reversible Adducts by Adsorption of Oxygen on Ce-ZrO2: An Unusual I•2 Ionic Superoxide
A phosphite dehydrogenase variant with promiscuous access to nicotinamide cofactor pools sustains fast phosphite-dependent growth of transplastomic chlamydomonas reinhardtii
Heterologous expression of the NAD+-dependent phosphite dehydrogenase (PTXD) bacterial enzyme from Pseudomonas stutzerii enables selective growth of transgenic organisms by using phosphite as sole phosphorous source. Combining phosphite fertilization with nuclear expression of the ptxD transgene was shown to be an alternative to herbicides in controlling weeds and contamination of algal cultures. Chloroplast expression of ptxD in Chlamydomonas reinhardtii was proposed as an environmentally friendly alternative to antibiotic resistance genes for plastid transformation. However, PTXD activity in the chloroplast is low, possibly due to the low NAD+/NADP+ ratio, limiting the efficiency of phosphite assimilation. We addressed the intrinsic constraints of the PTXD activity in the chloroplast and improved its catalytic efficiency in vivo via rational mutagenesis of key residues involved in cofactor binding. Transplastomic lines carrying a mutagenized PTXD version promiscuously used NADP+ and NAD+ for converting phosphite into phosphate and grew faster compared to those expressing the wild type protein. The modified PTXD enzyme also enabled faster and reproducible selection of transplastomic colonies by directly plating on phosphite-containing medium. These results allow using phosphite as selective agent for chloroplast transformation and for controlling biological contaminants when expressing heterologous proteins in algal chloroplasts, without compromising on culture performance
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