114 research outputs found
Infrastructure-led development and the peri-urban question : furthering crossover comparisons
Contemporary development policy portrays enhanced connectivity as the key to fostering economic growth in lagging regions. This global policy consensus and consequent infrastructure scramble have resulted in a proliferation of new urban spaces. These are dispersed, fragmentary and often unrecognised as urban by projects and plans centred on large-scale connective infrastructures to integrate remote regions into circuits of capital. Whilst our understanding of infrastructure-led development is informed by critical engagements with planetary urbanisation, global infrastructure and logistics, this position paper seeks to reconcile political economy analyses with situated studies closer to lived forms of heterogeneous precariousness in emerging urban worlds. Addressing recent debates that frame these bodies of scholarship as antagonistic, we emphasise the supplementarity of perspectives from within and beyond urban studies. This pluralism can be practised through comparisons that will (i) trace the geo-economic relationality of mega-infrastructures, which conditions directly and indirectly their planning, financing, construction and management, and (simultaneously or independently) (ii) examine difference in the diverse experiences of and responses to emergent infrastructural urbanisms of precarity. The article shows that genetic and generative comparisons can inform a research agenda on (peri-)urban precariousness, engaging policies with unmistakable global moorings but complex multi-scalar politics, diverging outcomes and situated resistances and appropriations
Between pacification and dialogue: Critical lessons from Colombia’s territorial peace
Colombia's peace process prioritised conflict-torn geographies ostensibly suffering from historical state absence. We examine the origins and afterlives of this 'territorial' peace using discourse analysis, archival research and field interviews. The state-initiated agenda exceeded the objective of structuring negotiations with FARC guerrillas, pointing to the transformative potential of social dialogue. The negotiating parties co-sponsored participatory rural development forums, which attracted numerous collectives. These diverse actors' visionary proposals to address neglected claims and conflicts influenced the government's and FARC's respective discourses, ultimately informing the 2016 peace agreement. Yet, state priorities for peace centred on international legitimation and post-conflict infrastructure development to accelerate foreign investment in export-oriented mining, oil extraction, and agri-business. The beleaguered FARC challenged government's narratives while struggling to rebuild organisational legitimacy and prevent fragmentation. Subsequent disappointments with fraught territorial development plans, a new government's securitization of peace programmes, and continuing violence mar the post-agreement period. Prior contributors to participatory forums have joined contentious actions against neglectful austerity, extractivist maldevelopment and targeted assassinations. Thus, we argue that Colombia's international lessons may reside less in governmental pacification programmes - the potential of state-sponsored participatory dialogues notwithstanding - than in resilient (post-)conflict communities open to exercising their peace imagination while remaining mobilised against new-and-old violences. Furthermore, the territorial peace saga illustrates productive overlaps between critical peace geographies and socio-territorial analysis - especially the territorial restructuring induced by neoliberal economic policies, the violent multiple territorialities of differentiated state presence in geographical peripheries and pluriversal struggles against ontological occupation addressed herein
Remaking south beach: Metropolitan gayborhood trajectories under homonormative entrepreneurialism
This paper contributes to research on metropolitan gayborhood trajectories and homonormative urban entrepreneurialism by assessing a South Florida case study. We probe allegations of gay men being displaced from South Beach and the opposing narrative of a sexually diverse city with undiminished appeal. To that end, we present expert informant interviews, participant observation, media archives, and census data showing that the remade gayborhood coexists and competes with other, more affordable LGBT nodes. While socioeconomic, demographic and cultural characteristics differentiate these clusters, exploratory spatial data analysis indicates that the majority of metropolitan same-sex households reside elsewhere. We acknowledge Miami Beachs recent pro-equality efforts, yet argue that homonormative politics conditions them. Public-private actions adopt corporate formats, prioritizing tourist-oriented initiatives and spectacular events that promote nonthreatening, market-friendly forms of sexual dissidence. The conclusion discusses implications for queer community-building in metropolitan regions fragmented by socio-spatial inequality and competitive city-marketing catering to heterogeneous yet exclusive global audiences
Deindustrialisation and the politics of subordinate degrowth: The case of Greater Buenos Aires, Argentina
Cities in low- and middle-income countries have experienced deindustrialisation as localised agglomerations that historically served domestic and regional markets have become exposed to highly productive global value chains as capital has been (re)allocated to primary sectors. State, corporate and social actors have responded to economic decline by embracing a range of coping and adaptation strategies, some of which are consistent with degrowth, but they are often combined with business-as-usual initiatives in pursuit of economic growth. We refer to this as subordinate degrowth because localised responses are conditioned by the subordinate position of countries and cities in the global economy. While we acknowledge its divergence from ‘pure’ ideal-type degrowth, we do not dismiss the transformative potential of incremental change. Indeed, we argue that any realistic strategy to spatialise degrowth within cities must recognise the indeterminacy and messiness of urban politics. We employ subordinate degrowth as an analytic to interpret responses to deindustrialisation and economic decline in Buenos Aires, Argentina. Our analysis attends to three meso-level blind spots that characterise much degrowth scholarship, between (1) particular and universal, (2) advanced-industrial and agrarian ideal-types and (3) past/current socio-technical regimes and ‘pure’ degrowth
Brownian dynamics approach to interacting magnetic moments
The question how to introduce thermal fluctuations in the equation of motion
of a magnetic system is addressed. Using the approach of the
fluctuation-dissipation theorem we calculate the properties of the noise for
both, the fluctuating field and fluctuating torque (force) representation. In
contrast to earlier calculations we consider the general case of a system of
interacting magnetic moments without the assumption of axial symmetry. We show
that the interactions do not result in any correlations of thermal fluctuations
in the field representation and that the same widely used formula can be used
in the most general case. We further prove that close to the equilibrium where
the fluctuation-dissipation theorem is valid, both, field and torque (force)
representations coincide, being different far away from it
Local media and geo-situated responses to Brexit: a quantitative analysis of Twitter, news and survey data
Societal debates and political outcomes are subject to news and social media influences, which are in turn subject to commercial and other forces. Local press are in decline, creating a "news gap". Research shows a contrary relationship between UK regions' economic dependence on EU membership and their voting in the 2016 UK EU membership referendum, raising questions about local awareness. We draw on a corpus of Twitter data which has been annotated for user location and Brexit vote intent, allowing us to investigate how location, topics of concern and Brexit stance are related. We compare this with a large corpus of articles from local and national news outlets, as well as survey data, finding evidence of a distinctly different focus in local reporting. National press focused more on terrorism and immigration than local press in most areas. Some Twitter users focused on immigration. Local press focused on trade, unemployment, local politics and agriculture. We find that remain voters shared interests more in keeping with local press on a per-region basis
Calibration of the Gamma-RAy Polarimeter Experiment (GRAPE) at a Polarized Hard X-Ray Beam
The Gamma-RAy Polarimeter Experiment (GRAPE) is a concept for an astronomical
hard X-ray Compton polarimeter operating in the 50 - 500 keV energy band. The
instrument has been optimized for wide-field polarization measurements of
transient outbursts from energetic astrophysical objects such as gamma-ray
bursts and solar flares. The GRAPE instrument is composed of identical modules,
each of which consists of an array of scintillator elements read out by a
multi-anode photomultiplier tube (MAPMT). Incident photons Compton scatter in
plastic scintillator elements and are subsequently absorbed in inorganic
scintillator elements; a net polarization signal is revealed by a
characteristic asymmetry in the azimuthal scattering angles. We have
constructed a prototype GRAPE module containing a single CsI(Na) calorimeter
element, at the center of the MAPMT, surrounded by 60 plastic elements. The
prototype has been combined with custom readout electronics and software to
create a complete "engineering model" of the GRAPE instrument. This engineering
model has been calibrated using a nearly 100% polarized hard X-ray beam at the
Advanced Photon Source at Argonne National Laboratory. We find modulation
factors of 0.46 +/- 0.06 and 0.48 +/- 0.03 at 69.5 keV and 129.5 keV,
respectively, in good agreement with Monte Carlo simulations. In this paper we
present details of the beam test, data analysis, and simulations, and discuss
the implications of our results for the further development of the GRAPE
concept.Comment: 35 pages, 14 figures, accepted for publication in NIM-
Prioritizing disease and trait causal variants at the TNFAIP3 locus using functional and genomic features
Genome-wide association studies have associated thousands of genetic variants with complex traits and diseases, but pinpointing the causal variant(s) among those in tight linkage disequilibrium with each associated variant remains a major challenge. Here, we use seven experimental assays to characterize all common variants at the multiple disease-associated TNFAIP3 locus in five disease-relevant immune cell lines, based on a set of features related to regulatory potential. Trait/disease-associated variants are enriched among SNPs prioritized based on either: (1) residing within CRISPRi-sensitive regulatory regions, or (2) localizing in a chromatin accessible region while displaying allele-specific reporter activity. Of the 15 trait/disease-associated haplotypes at TNFAIP3, 9 have at least one variant meeting one or both of these criteria, 5 of which are further supported by genetic fine-mapping. Our work provides a comprehensive strategy to characterize genetic variation at important disease-associated loci, and aids in the effort to identify trait causal genetic variants
The genetic architecture of the human cerebral cortex
INTRODUCTION
The cerebral cortex underlies our complex cognitive capabilities. Variations in human cortical surface area and thickness are associated with neurological, psychological, and behavioral traits and can be measured in vivo by magnetic resonance imaging (MRI). Studies in model organisms have identified genes that influence cortical structure, but little is known about common genetic variants that affect human cortical structure.
RATIONALE
To identify genetic variants associated with human cortical structure at both global and regional levels, we conducted a genome-wide association meta-analysis of brain MRI data from 51,665 individuals across 60 cohorts. We analyzed the surface area and average thickness of the whole cortex and 34 cortical regions with known functional specializations.
RESULTS
We identified 306 nominally genome-wide significant loci (P < 5 × 10−8) associated with cortical structure in a discovery sample of 33,992 participants of European ancestry. Of the 299 loci for which replication data were available, 241 loci influencing surface area and 14 influencing thickness remained significant after replication, with 199 loci passing multiple testing correction (P < 8.3 × 10−10; 187 influencing surface area and 12 influencing thickness).
Common genetic variants explained 34% (SE = 3%) of the variation in total surface area and 26% (SE = 2%) in average thickness; surface area and thickness showed a negative genetic correlation (rG = −0.32, SE = 0.05, P = 6.5 × 10−12), which suggests that genetic influences have opposing effects on surface area and thickness. Bioinformatic analyses showed that total surface area is influenced by genetic variants that alter gene regulatory activity in neural progenitor cells during fetal development. By contrast, average thickness is influenced by active regulatory elements in adult brain samples, which may reflect processes that occur after mid-fetal development, such as myelination, branching, or pruning. When considered together, these results support the radial unit hypothesis that different developmental mechanisms promote surface area expansion and increases in thickness.
To identify specific genetic influences on individual cortical regions, we controlled for global measures (total surface area or average thickness) in the regional analyses. After multiple testing correction, we identified 175 loci that influence regional surface area and 10 that influence regional thickness. Loci that affect regional surface area cluster near genes involved in the Wnt signaling pathway, which is known to influence areal identity.
We observed significant positive genetic correlations and evidence of bidirectional causation of total surface area with both general cognitive functioning and educational attainment. We found additional positive genetic correlations between total surface area and Parkinson’s disease but did not find evidence of causation. Negative genetic correlations were evident between total surface area and insomnia, attention deficit hyperactivity disorder, depressive symptoms, major depressive disorder, and neuroticism.
CONCLUSION
This large-scale collaborative work enhances our understanding of the genetic architecture of the human cerebral cortex and its regional patterning. The highly polygenic architecture of the cortex suggests that distinct genes are involved in the development of specific cortical areas. Moreover, we find evidence that brain structure is a key phenotype along the causal pathway that leads from genetic variation to differences in general cognitive function
New insights into the genetic etiology of Alzheimer's disease and related dementias
Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele
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