Social Mobility and Spatialised Slowness

This article analyses the individual aspirations of Sierra Leoneans living in France in relation to normative expectations related to mobility. It argues that aspirations and expectations are expressions of spatialized forms of social becoming situated within broader norms concerning socially-valued forms of mobility. Aspirations to social mobility link up distinct places in a fragmented transnational field, transform them as value-laden spaces, and inform migrants’ assessment of their own trajectory within them. Individual aspirations are formulated with regard to spaces migrants have left, spaces they live in, and spaces they would like to reach. Sierra Leoneans living in France have reached a ‘destination country’ and yet, do not experience their situation as the ideal migratory path. Their achievements are measured with regard to expectations of social mobility as imagined in English-speaking spaces, thereby reinforcing the narrative of mobility and the persistence of local idioms of ‘success’ based on historical transnational connections.

The memory of migration: in-depth interview with immigrant adolescents from the moldovan diaspora in Italy

The paper is an analysis of the migratory path of immigrant Moldovan adolescents from Italy, emphasizing the impact of leaving the country of origin on social inclusion, the specificity of life after family reunification and the new beginning in the context of the host country. Highlights the difficulties of young people, related to separation from loved ones, meeting with the new condition of "immigrant" and rebuilding family relationship.

Torture against migrants: A structural and global phenomenon, and its social roots

The article examines the relationship between torture and migration, highlighting how torture has become a structural element of the migratory experience in the majority of the world; sometimes torture is the cause for departure, it is a frequent experience along the migratory path, it is a reality that migrants are sometimes forced to confront in receiving countries. This is specifically the result of the convergence between the amplification of torture (the "torture crisis") and the worsening of the conditions of migration (the "war on migrants"). The article analyzes the different factors underlying these processes, highlighting that torture against migrants is a global phenomenon that has a close link with the tightening of migration policies, the three-fold process of precarization, illegalization and criminalization of migration, the escalation of racism, all elements that, together with some social processes of contemporary society - the securitization policies, the politics of fear, hyper-detention, the theories on the criminal law of the enemy - promote the production of contexts, environments, and situations permeable to torture.

Revealing migratory path, important stopovers and non-breeding areas of a boreal songbird in steep decline

The Olive-sided Flycatcher (Contopus cooperi) is a steeply declining aerial insectivore with one of the longest migrations of any North American passerine. We deployed light-level geolocators and archival GPS tags on breeders in boreal Alaska to determine migratory routes, important stopovers and non-breeding locations. Data from 16 individuals revealed a median 23,555 km annual journey (range: 19,387, 27,292 km) over 95 days (range: 83, 139 days) with wintering occurring in three regions of South America (NW Colombia/Ecuador, central Peru and W Brazil/S Peru). We developed a new method to identify “Important Stopovers” by quantifying intensity of use (a function of bird numbers and stop durations) along migratory routes. We identified 13 Important Stopovers that accounted for ~66% of the annual migratory period, suggestive of refueling activities. Some sites coincided with key areas previously identified for other Neotropical-Nearctic migrants. Percent land “protected” at Important Stopovers, as defined by IUCN, ranged from 3.8% to 49.3% (mean [95% CI]: 17.3% [9.6, 25.0]). Total migration speed did not differ by season (median: 255 km day-1, range: 182, 295km day-1), despite greater spring travel distances. Birds with longer non-breeding periods, however, migrated north faster. Climate-driven mismatches in migratory timing may be less of a concern for western than for eastern flycatcher populations, given recent con-generic analyses (C. sordidulus, C. virens). However, accelerated high-latitude changes, may nonetheless impact boreal breeders.

Ariadne’s Thread in the Developing Cerebral Cortex: Mechanisms Enabling the Guiding Role of the Radial Glia Basal Process during Neuron Migration

Radial neuron migration in the developing cerebral cortex is a complex journey, starting in the germinal zones and ending in the cortical plate. In mice, migratory distances can reach several hundreds of microns, or millimeters in humans. Along the migratory path, radially migrating neurons slither through cellularly dense and complex territories before they reach their final destination in the cortical plate. This task is facilitated by radial glia, the neural stem cells of the developing cortex. Indeed, radial glia have a unique bipolar morphology, enabling them to serve as guides for neuronal migration. The key guiding structure of radial glia is the basal process, which traverses the entire thickness of the developing cortex. Neurons recognize the basal process as their guide and maintain physical interactions with this structure until the end of migration. Thus, the radial glia basal process plays a key role during radial migration. In this review, we highlight the pathways enabling neuron-basal process interactions during migration, as well as the known mechanisms regulating the morphology of the radial glia basal process. Throughout, we describe how dysregulation of these interactions and of basal process morphology can have profound effects on cortical development, and therefore lead to neurodevelopmental diseases.

Perilaku Migrasi Sikep Madu-Asia dalam Pemanfaatan Lanskap di Flores Bagian Timur, Indonesia Berdasarkan Data Satellite-tracking

Raptor migration is complex phenomenon of migration which involving of millions of individual birds flying hundreds or thousands kilometers, between breeding habitat and wintering habitat. Migratory behavior consisted of period, route, and other aspects that affect the ecology of migratory birds. Pernis ptylorhynchus, Oriental honey-buzzard (OHB) is one of migratory raptors which have satellite tracked by ARGOS since 2003. Eastern part of Flores Islands consisted of small islands (23 islands) were identified as OHB’s migratory path to reach their wintering habitats in Kupang and Timor Island. This study has aimed to identify and analyze the OHB’s migratory behavior in Eastern part of Flores Islands. Four individuals OHB have satellite tracked in the period of 2007-2012 were used as main data for analyzing their migratory behavior. There was no particular pattern found on the way of OHBs selected islands for their stopover site because of the existence of small islands cluster provide variety of route for each OHBs. The length of their stay found relatively constant every year and tend to be stay longer on larger islands than the smaller one such as Flores Island and Lembata Island. This is apparently due to the larger islands provide more food supply than smaller islands.

Malaria parasites differentially sense environmental elasticity during transmission

Transmission of malaria-causing parasites to and by the mosquito rely on active parasite migration and constitute bottlenecks in the Plasmodium life cycle. Parasite adaption to the biochemically and physically different environments must hence be a key evolutionary driver for transmission efficiency. To probe how subtle but physiologically relevant changes in environmental elasticity impact parasite migration, we introduce 2D and 3D polyacrylamide gels to study ookinetes, the parasite forms emigrating from the mosquito blood meal and sporozoites, the forms transmitted to the vertebrate host. We show that ookinetes adapt their migratory path but not their speed to environmental elasticity and are motile for over 24 hours on soft substrates. In contrast, sporozoites evolved more short-lived rapid gliding motility for rapidly crossing the skin. Strikingly, sporozoites are highly sensitive to substrate elasticity possibly to avoid adhesion on soft endothelial cells on their long way to the liver. Hence the two migratory stages of Plasmodium evolved different strategies to overcome the physical challenges posed by the respective environments and barriers they encounter.HighlightsPlasmodium ookinetes can move for over 24 hours on very soft substrates mimicking the blood mealPlasmodium ookinetes change their migration path according to substrate stiffnessPlasmodium sporozoites are highly sensitive to subtle changes in substrate elasticitySporozoite may have evolved to not attach to the soft endothelium to help reach the liver

Single Cortical Microinfarcts Lead to Widespread Microglia/Macrophage Migration Along the White Matter

Loss of cognitive function with aging is a complex and poorly understood process. Recently, clinical research has linked the occurrence of cortical microinfarcts to cognitive decline. Cortical microinfarcts form following the occlusion of penetrating vessels and are considered to be restricted to the proximity of the occluded vessel. Whether and how such local events propagate and affect remote brain regions remain unknown. To this end, we combined histological analysis and longitudinal diffusion tensor imaging (DTI), following the targeted-photothrombotic occlusion of single cortical penetrating vessels. Occlusions resulted in distant tissue reorganization across the mouse brain. This remodeling co-occurred with the formation of a microglia/macrophage migratory path along subcortical white matter tracts, reaching the contralateral hemisphere through the corpus callosum and leaving a microstructural signature detected by DTI-tractography. CX3CR1-deficient mice exhibited shorter trail lengths, differential remodeling, and only ipsilateral white matter tract changes. We concluded that microinfarcts lead to brain-wide remodeling in a microglial CX3CR1-dependent manner.

Harmonization of postmortem donations for pediatric brain tumors and molecular characterization of diffuse midline gliomas

Children diagnosed with brain tumors have the lowest overall survival of all pediatric cancers. Recent molecular studies have resulted in the discovery of recurrent driver mutations in many pediatric brain tumors. However, despite these molecular advances, the clinical outcomes of high grade tumors, including H3K27M diffuse midline glioma (H3K27M DMG), remain poor. To address the paucity of tissue for biological studies, we have established a comprehensive protocol for the coordination and processing of donated specimens at postmortem. Since 2010, 60 postmortem pediatric brain tumor donations from 26 institutions were coordinated and collected. Patient derived xenograft models and cell cultures were successfully created (76% and 44% of attempts respectively), irrespective of postmortem processing time. Histological analysis of mid-sagittal whole brain sections revealed evidence of treatment response, immune cell infiltration and the migratory path of infiltrating H3K27M DMG cells into other midline structures and cerebral lobes. Sequencing of primary and disseminated tumors confirmed the presence of oncogenic driver mutations and their obligate partners. Our findings highlight the importance of postmortem tissue donations as an invaluable resource to accelerate research, potentially leading to improved outcomes for children with aggressive brain tumors.