Showing papers by "University of Winnipeg published in 2017"

The Global Refugee Crisis: Empirical Evidence and Policy Implications for Improving Public Attitudes and Facilitating Refugee Resettlement

Abstract: The number of refugees across the globe is at an alarming high and is expected to continue to rise for the foreseeable future. As a result, finding durable solutions for refugees has become a major challenge worldwide. The literature reviewed and policy implications discussed in this article are based on the premise that one of the major solutions to the refugee crisis must be refugee resettlement in new host countries. For such a solution to succeed, however, requires relatively favorable attitudes by members of host societies, protection of the well-being of refugees, and effective integration of refugees into new host countries. In this context, we begin by reviewing the literature on determinants of public attitudes toward refugees, the acculturation of refugees in host societies, and factors affecting refugee mental health, all of which are directly relevant to the success of the resettlement process. We then turn our attention to the policy implications of these literatures, and discuss strategies for improving public attitudes toward refugees and refugee resettlement in host countries; for improving the resettlement process to reduce mental health challenges; and for supporting the long-term acculturation and integration of refugees in their new homes.

Combined Analysis of Neutrino and Antineutrino Oscillations at T2K.

Abstract: T2K reports its first results in the search for CP violation in neutrino oscillations using appearance and disappearance channels for neutrino- and antineutrino-mode beam. The data include all runs from Jan 2010 to May 2016 and comprise $7.482\times10^{20}$,protons on target in neutrino mode, which yielded in the far detector 32 e-like and 135 $\mu$-like events, and $7.471\times10^{20}$,protons on target in antineutrino mode which yielded 4 e-like and 66 $\mu$-like events. Reactor measurements of $\sin^{2}2\theta_{13}$ have been used as an additional constraint. The one-dimensional confidence interval at 90% for $\delta_{CP}$ spans the range ($-3.13$, $-0.39$) for normal mass ordering. The CP conservation hypothesis ($\delta_{CP}=0,\pi$) is excluded at 90% C.L.

Plants of the Genus Zingiber as a Source of Bioactive Phytochemicals: From Tradition to Pharmacy

Abstract: Plants of the genus Zingiber (Family Zingiberaceae) are widely used throughout the world as food and medicinal plants. They represent very popular herbal remedies in various traditional healing systems; in particular, rhizome of Zingiber spp. plants has a long history of ethnobotanical uses because of a plethora of curative properties. Antimicrobial activity of rhizome essential oil has been extensively confirmed in vitro and attributed to its chemical components, mainly consisting of monoterpene and sesquiterpene hydrocarbons such as α-zingiberene, ar-curcumene, β-bisabolene and β-sesquiphellandrene. In addition, gingerols have been identified as the major active components in the fresh rhizome, whereas shogaols, dehydrated gingerol derivatives, are the predominant pungent constituents in dried rhizome. Zingiber spp. may thus represent a promising and innovative source of natural alternatives to chemical food preservatives. This approach would meet the increasing concern of consumers aware of the potential health risks associated with the conventional antimicrobial agents in food. This narrative review aims at providing a literature overview on Zingiber spp. plants, their cultivation, traditional uses, phytochemical constituents and biological activities.

Internal phosphorus loading in Canadian fresh waters: a critical review and data analysis

Abstract: Many physical, chemical, and biological processes in freshwater ecosystems mobilize the nutrient phosphorus (P) from sediments, which in turn may contribute to the formation of harmful algal blooms...

Enrichment of beneficial bacteria in the skin microbiota of bats persisting with white-nose syndrome

Abstract: Infectious diseases of wildlife are increasing worldwide with implications for conservation and human public health. The microbiota (i.e. microbial community living on or in a host) could influence wildlife disease resistance or tolerance. White-nose syndrome (WNS), caused by the fungus Pseudogymnoascus destructans (Pd), has killed millions of hibernating North American bats since 2007. We characterized the skin microbiota of naive, pre-WNS little brown bats (Myotis lucifugus) from three WNS-negative hibernation sites and persisting, previously exposed bats from three WNS-positive sites to test the hypothesis that the skin microbiota of bats shifts following WNS invasion. Using high-throughput 16S rRNA gene sequencing on 66 bats and 11 environmental samples, we found that hibernation site strongly influenced the composition and diversity of the skin microbiota. Bats from WNS-positive and WNS-negative sites differed in alpha and beta diversity, as well as in microbiota composition. Alpha diversity was reduced in persisting, WNS-positive bats, and the microbiota profile was enriched with particular taxa such Janthinobacterium, Micrococcaceae, Pseudomonas, Ralstonia, and Rhodococcus. Some of these taxa are recognized for their antifungal activity, and specific strains of Rhodococcus and Pseudomonas are known to inhibit Pd growth. Composition of the microbial community in the hibernaculum environment and the community on bat skin was superficially similar but differed in relative abundance of some bacterial taxa. Our results are consistent with the hypothesis that Pd invasion leads to a shift in the skin microbiota of surviving bats and suggest the possibility that the microbiota plays a protective role for bats facing WNS. The detection of what appears to be enrichment of beneficial bacteria in the skin microbiota of persisting bats is a promising discovery for species re-establishment. Our findings highlight not only the potential value of management actions that might encourage transmission, growth, and establishment of beneficial bacteria on bats, and within hibernacula, but also the potential risks of such management actions.

Myristoylation: An Important Protein Modification in the Immune Response.

Abstract: Increasing biochemical and genetic evidence confirms that myristoylation is an evolutionary conserved process of lipid modification in many eukaryotic and viral proteins. The discovery that the N-terminal blocking group of cyclic AMP-dependent protein kinase is a myristic acid, some 33 years ago, led to the birth of the field of ‘myristoylation’, dedicated to understanding the significance of protein myristoylation. Although the field is in its infancy, an increasing number of studies have appeared addressing the mechanisms and significance of N-myristoylation in various aspects of cellular signaling. N-Myristoylation is known to occur in mammalian, plant, viral and fungal proteins. Many proteins involved in a variety of signal cascades and cellular differentiation are myristoylated. These include the catalytic subunit of cAMP-dependent protein kinase, the β-subunit of calcineurin, the α-subunit of several G-proteins, the cellular and transforming forms of pp60src. Given the indispensible role of myristoylation in cellular functions, in this review, we examine the myriad functional implications of myristoylation with respect to immune function and regulation.

Exploring the spatial variability of soil properties in an Alfisol soil catena

Abstract: Detailed digital soil maps showing the spatial heterogeneity of soil properties consistent with the landscape are required for site-specific management of plant nutrients, land use planning and process-based environmental modeling. We characterized the short-scale spatial heterogeneity of soil properties in an Alfisol catena in a tropical landscape of Sri Lanka. The impact of different land-uses (paddy, vegetable and un-cultivated) was examined to assess the impact of anthropogenic activities on the variability of soil properties at the catenary level. Conditioned Latin hypercube sampling was used to collect 58 geo-referenced topsoil samples (0–30 cm) from the study area. Soil samples were analyzed for pH, electrical conductivity (EC), organic carbon (OC), cation exchange capacity (CEC) and texture. The spatial correlation between soil properties was analyzed by computing cross-variograms and subsequent fitting of theoretical model. Spatial distribution maps were developed using ordinary kriging. The range of soil properties, pH: 4.3–7.9; EC: 0.01–0.18 dS m− 1; OC: 0.1–1.37%; CEC: 0.44–11.51 cmol (+) kg− 1; clay: 1.5–25% and sand: 59.1–84.4% and their coefficient of variations indicated a large variability in the study area. Electrical conductivity and pH showed a strong spatial correlation which was reflected by the cross-variogram close to the hull of the perfect correlation. Moreover, cross-variograms calculated for EC and Clay, CEC and OC, CEC and clay and CEC and pH indicated weak positive spatial correlation between these properties. Relative nugget effect (RNE) calculated from variograms showed strongly structured spatial variability for pH, EC and sand content (RNE < 25%) while CEC, organic carbon and clay content showed moderately structured spatial variability (25% < RNE < 75%). Spatial dependencies for examined soil properties ranged from 48 to 984 m. The mixed effects model fitting followed by Tukey's post-hoc test showed significant effect of land use on the spatial variability of EC. Our study revealed a structured variability of topsoil properties in the selected tropical Alfisol catena. Except for EC, observed variability was not modified by the land uses. Investigated soil properties showed distinct spatial structures at different scales and magnitudes of strength. Our results will be useful for digital soil mapping, site specific management of soil properties, developing appropriate land use plans and quantifying anthropogenic impacts on the soil system.

Moving towards a more inclusive patient and public involvement in health research paradigm: the incorporation of a trauma-informed intersectional analysis.

Abstract: The concept of patient engagement in health research has received growing international recognition over recent years. Yet despite some critical advancements, we argue that the concept remains problematic as it negates the very real complexities and context of people’s lives. Though patient engagement conceptually begins to disrupt the identity of “researcher,” and complicate our assumptions and understandings around expertise and knowledge, it continues to essentialize the identity of “patient” as a homogenous group, denying the reality that individuals’ economic, political, cultural, subjective and experiential lives intersect in intricate and multifarious ways. Patient engagement approaches that do not consider the simultaneous interactions between different social categories (e.g. race, ethnicity, Indigeneity, gender, class, sexuality, geography, age, ability, immigration status, religion) that make up social identity, as well as the impact of systems and processes of oppression and domination (e.g. racism, colonialism, classism, sexism, ableism, homophobia) exclude the involvement of individuals who often carry the greatest burden of illness — the very voices traditionally less heard in health research. We contend that in order to be a more inclusive and meaningful approach that does not simply reiterate existing health inequities, it is important to reconceptualize patient engagement through a health equity and social justice lens by incorporating a trauma-informed intersectional analysis. This article provides key concepts to the incorporation of a trauma-informed intersectional analysis and important questions to consider when developing a patient engagement strategy in health research training, practice and evaluation. In redefining the identity of both “patient” and “researcher,” spaces and opportunities to resist and renegotiate power within the intersubjective relations can be recognized and addressed, in turn helping to build trust, transparency and resiliency — integral to the advancement of the science of patient engagement in health research.

Should Immediate Autologous Breast Reconstruction Be Considered in Women Who Require Postmastectomy Radiation Therapy? A Prospective Analysis of Outcomes.

Abstract: Background:In women who require postmastectomy radiation therapy, immediate autologous breast reconstruction is often discouraged. The authors prospectively evaluated postoperative morbidity and satisfaction reported by women undergoing delayed or immediate autologous breast reconstruction in the se

An examination of the default mode network in individuals with autonomous sensory meridian response (ASMR)

Abstract: Autonomous Sensory Meridian Response (ASMR) is a perceptual condition in which specific visual and auditory stimuli consistently trigger tingling sensations on the scalp and neck, sometimes spreading to the back and limbs. These triggering stimuli are often social, almost intimate, in nature (e.g., hearing whispering, or watching someone brush her hair), and often elicit a calm and positive emotional state. Surprisingly, despite its prevalence in the general population, no published study has examined the neural underpinnings of ASMR. In the current study, the default mode network (DMN) of 11 individuals with ASMR was contrasted to that of 11 matched controls. The results indicated that the DMN of individuals with ASMR showed significantly less functional connectivity than that of controls. The DMN of individuals with ASMR also demonstrated increased connectivity between regions in the occipital, frontal, and temporal cortices, suggesting that ASMR was associated with a blending of multiple restin...

An Examination of Personality Traits Associated with Autonomous Sensory Meridian Response (ASMR).

Abstract: Autonomous Sensory Meridian Response (ASMR) is a perceptual condition in which the presentation of particular audio-visual stimuli triggers intense, pleasurable tingling sensations in the head and neck regions, which may spread to the periphery of the body. These triggering stimuli are often socially intimate in nature, and usually involve repetition of movements and/or sounds (e.g., hearing whispering, watching someone brush her hair). Reports of ASMR experiences first appeared in online communities in 2010; since this time, these communities have expanded, with some groups consisting of over 100,000 members. However, despite the apparent prevalence of ASMR, there is currently no research on the personality characteristics that co-occur with this condition. In the current study, 290 individuals with ASMR and 290 matched controls completed the Big Five Personality Inventory (BFI; John, Donahue, & Kentle, 1999); participants with ASMR also completed a questionnaire related to their ASMR phenomenology. Individuals with ASMR demonstrated significantly higher scores on Openness-to-Experience and Neuroticism, and significantly lower levels of Conscientiousness, Extraversion, and Agreeableness compared to matched controls. Further, ratings of subjective ASMR intensity in response to 14 common ASMR stimuli were positively correlated with the Openness-to-Experience and Neuroticism dimensions of the BFI. These results provide preliminary evidence that ASMR is associated with specific personality traits and suggest avenues for further investigation.

Dengue seroprevalence, seroconversion and risk factors in Dhaka, Bangladesh

Abstract: Background Dengue virus (DENV) activity has been reported in Dhaka, Bangladesh since the early 1960s with the greatest burden of dengue fever and dengue hemorrhagic fever cases observed in 2000. Since this time, the intensity of dengue activity has varied from year to year, and its determining factors remained relatively unknown. In light of such gaps in knowledge, the main objectives of this study were to determine the magnitude of seroprevalence and seroconversion among the surveyed population, and establish the individual/household level risk factors for the presence of DENV antibodies among all age groups of target populations in the city of Dhaka. Methodology/Principal findings Considering the lack of fine scale investigations on the factors driving dengue activity in Bangladesh, a prospective cohort study involving serological surveys was undertaken with participant interviews and blood donation across the city of Dhaka in 2012. Study participants were recruited from 12 of 90 wards and blood samples were collected during both the pre-monsoon (n = 1125) and post-monsoon (n = 600) seasons of 2012. The findings revealed that the seroprevalence in all pre-monsoon samples was 80.0% (900/1125) while the seropositivity in the pre-monsoon samples that had paired post-monsoon samples was 83.3% (503/600). Of the 97 paired samples that were negative at the pre-monsoon time point, 56 were positive at the post-monsoon time point. This resulted in a seroprevalence of 93.2% (559/600) among individuals tested during the post-monsoon period. Seroprevalence trended higher with age with children exhibiting a lower seropositivity as compared to adults. Results from this study also indicated that DENV strains were the only flaviviruses circulating in Dhaka in 2012. A multivariate analysis revealed that age, possession of indoor potted plants, and types of mosquito control measures were significant factors associated with DENV seroprevalence; while attendance in public/mass gatherings, and use of mosquito control measures were significantly associated with DENV seroconversion after adjusting for all other variables. Conclusions/Significance Our study suggests that there is a high level of endemic dengue virus circulation in the city of Dhaka which has resulted in significant DENV seroprevalence among its residents. Seropositivity increased with age, however, a substantial proportion of children are at risk for DENV infections. Our serological analysis also documents considerable DENV seroconversion among study participants which indicates that a large proportion of the population in the city of Dhaka were newly exposed to DENV during the study period (pre-and post-monsoon 2012). High levels of seroconversion suggest that there was an intense circulation of DENV in 2012 and this may have resulted in a significant risk for viral associated illness. Findings of our study further indicated that home-based interventions, such as removing indoor potted plants and increased bed net use, in addition to vector control measures in public parks, would reduce exposure to DENV and further decrease risk of viral associated disease.

Aquatic Global Passive Sampling (AQUA-GAPS) Revisited: First Steps toward a Network of Networks for Monitoring Organic Contaminants in the Aquatic Environment

Abstract: Organic contaminants, in particular persistent organic pollutants (POPs), adversely affect water quality and aquatic food webs across the globe. As of now, there is no globally consistent information available on concentrations of dissolved POPs in water bodies. The advance of passive sampling techniques has made it possible to establish a global monitoring program for these compounds in the waters of the world, which we call the Aquatic Global Passive Sampling (AQUA-GAPS) network. A recent expert meeting discussed the background, motivations, and strategic approaches of AQUA-GAPS, and its implementation as a network of networks for monitoring organic contaminants (e.g., POPs and others contaminants of concern). Initially, AQUA-GAPS will demonstrate its operating principle via two proof-of-concept studies focused on the detection of legacy and emerging POPs in freshwater and coastal marine sites using both polyethylene and silicone passive samplers. AQUA-GAPS is set up as a decentralized network, which is...

Efficacy of a probiotic bacterium to treat bats affected by the disease white-nose syndrome

Abstract: Summary The management of infectious diseases is an important conservation concern for a growing number of wildlife species. However, effective disease control in wildlife is challenging because feasible management options are often lacking. White-nose syndrome (WNS) is an infectious disease of hibernating bats that currently threatens several North American species with extinction. Currently, no effective treatments exist for WNS. We conducted a laboratory experiment to test the efficacy of probiotic treatment with Pseudomonas fluorescens, a bacterium that naturally occurs on bats, to reduce disease severity and improve survival of little brown bats Myotis lucifugus exposed to Pseudogymnoascus destructans, the fungal pathogen that causes WNS. We found that application of the probiotic bacteria at the time of fungal infection reduced several measures of disease severity and increased survival, whereas bacterial treatment prior to pathogen exposure had no effect on survival and worsened disease severity. Synthesis and applications. Our results suggest that probiotic treatment with Ps. fluorescens has potential for white-nose syndrome disease management, but the timing of application is critical and should coincide with natural exposure of bats to P. destructans. These results add to the growing knowledge of how natural host microbiota can be implemented as a biocontrol treatment to influence disease outcomes.

Visible/near-infrared spectral diversity from in situ observations of the Bagnold Dune Field sands in Gale Crater, Mars

Abstract: As part of the Bagnold Dune campaign conducted by Mars Science Laboratory rover Curiosity, visible/near-infrared reflectance spectra of dune sands were acquired using Mast Camera (Mastcam) multispectral imaging (445–1013 nm) and Chemistry and Camera (ChemCam) passive point spectroscopy (400–840 nm). By comparing spectra from pristine and rover-disturbed ripple crests and troughs within the dune field, and through analysis of sieved grain size fractions, constraints on mineral segregation from grain sorting could be determined. In general, the dune areas exhibited low relative reflectance, a weak ~530 nm absorption band, an absorption band near 620 nm, and a spectral downturn after ~685 nm consistent with olivine-bearing sands. The finest grain size fractions occurred within ripple troughs and in the subsurface and typically exhibited the strongest ~530 nm bands, highest relative reflectances, and weakest red/near-infrared ratios, consistent with a combination of crystalline and amorphous ferric materials. Coarser-grained samples were the darkest and bluest and exhibited weaker ~530 nm bands, lower relative reflectances, and stronger downturns in the near-infrared, consistent with greater proportions of mafic minerals such as olivine and pyroxene. These grains were typically segregated along ripple crests and among the upper surfaces of grain flows in disturbed sands. Sieved dune sands exhibited progressive decreases in reflectance with increasing grain size, as observed in laboratory spectra of olivine size separates. The continuum of spectral features observed between the coarse- and fine-grained dune sands suggests that mafic grains, ferric materials, and air fall dust mix in variable proportions depending on aeolian activity and grain sorting.

Infrared Spectrometer for ExoMars: A Mast-Mounted Instrument for the Rover

Abstract: ISEM (Infrared Spectrometer for ExoMars) is a pencil-beam infrared spectrometer that will measure reflected solar radiation in the near infrared range for context assessment of the surface mineralogy in the vicinity of the ExoMars rover. The instrument will be accommodated on the mast of the rover and will be operated together with the panoramic camera (PanCam), high-resolution camera (HRC). ISEM will study the mineralogical and petrographic composition of the martian surface in the vicinity of the rover, and in combination with the other remote sensing instruments, it will aid in the selection of potential targets for close-up investigations and drilling sites. Of particular scientific interest are water-bearing minerals, such as phyllosilicates, sulfates, carbonates, and minerals indicative of astrobiological potential, such as borates, nitrates, and ammonium-bearing minerals. The instrument has an ∼1° field of view and covers the spectral range between 1.15 and 3.30 μm with a spectral resoluti...

White-nose syndrome increases torpid metabolic rate and evaporative water loss in hibernating bats.

Abstract: Fungal diseases of wildlife typically manifest as superficial skin infections but can have devastating consequences for host physiology and survival. White-nose syndrome (WNS) is a fungal skin dise...

Evolution of Occator Crater on (1) Ceres

Abstract: The Framing Camera project is financially supported by the Max Planck Society and the German Space Agency (DLR).

Costs of services for homeless people with mental illness in 5 Canadian cities: a large prospective follow-up study.

Abstract: Background Limited evidence on the costs of homelessness in Canada is available. We estimated the average annual costs, in total and by cost category, that homeless people with mental illness engender from the perspective of society. We also identified individual characteristics associated with higher costs. Methods As part of the At Home/Chez Soi trial of Housing First for homeless people with mental illness, 990 participants were assigned to the usual-treatment (control) group in 5 Canadian cities (Vancouver, Winnipeg, Toronto, Montreal and Moncton) between October 2009 and June 2011. They were followed for up to 2 years. Questionnaires ascertained service use and income, and city-specific unit costs were estimated. We adjusted costs for site differences in sample characteristics. We used generalized linear models to identify individual-level characteristics associated with higher costs. Results Usable data were available for 937 participants (94.6%). Average annual costs (excluding medications) per person in Vancouver, Winnipeg, Toronto, Montreal and Moncton were $53 144 (95% confidence interval [CI] $46 297-$60 095), $45 565 (95% CI $41 039-$50 412), $58 972 (95% CI $52 237-$66 085), $56 406 (95% CI $50 654-$62 456) and $29 610 (95% CI $24 995-$34 480), respectively. Net costs ranged from $15 530 to $341 535. Distributions of costs across categories varied significantly across cities. Lower functioning and a history of psychiatric hospital stays were the most important predictors of higher costs. Interpretation Homeless people with mental illness generate very high costs for society. Programs are needed to reorient this spending toward more effectively preventing homelessness and toward meeting the health, housing and social service needs of homeless people.

Criteria for quality in qualitative research and use of freedom of information requests in the social sciences

Abstract: Access to information (ATI) and freedom of information (FOI) requests are an under-used means of producing data in the social sciences, especially across Canada and the United States. We use litera...

The Truce-Smiles Rearrangement and Related Reactions: A Review

Abstract: The Truce–Smiles rearrangement is an X → C aryl migration reaction that is achieved by an intramolecular nucleophilic aromatic substitution pathway. The reaction exhibits a wide substrate scope with respect to a migrating aryl ring and leaving group, appearing in many different tandem reaction sequences, to achieve a wide variety of product outcomes. We present an extensive survey of reported examples of the Truce–Smiles rearrangement from the chemistry literature (1950s until present) organized by various substrate design variables or aspects of the reaction method. Present deficiencies in our understanding of the reaction are identified with recommendations for future research directions and useful developments in the application of the reaction are celebrated.

Evolution of Occator Crater on (1) Ceres

Abstract: The Framing Camera project is financially supported by the Max Planck Society and the German Space Agency (DLR).

A persistently infecting coronavirus in hibernating Myotis lucifugus, the North American little brown bat

Abstract: Bats are important reservoir hosts for emerging viruses, including coronaviruses that cause diseases in people. Although there have been several studies on the pathogenesis of coronaviruses in humans and surrogate animals, there is little information on the interactions of these viruses with their natural bat hosts. We detected a coronavirus in the intestines of 53/174 hibernating little brown bats (Myotis lucifugus), as well as in the lungs of some of these individuals. Interestingly, the presence of the virus was not accompanied by overt inflammation. Viral RNA amplified from little brown bats in this study appeared to be from two distinct clades. The sequences in clade 1 were very similar to the archived sequence derived from little brown bats and the sequences from clade 2 were more closely related to the archived sequence from big brown bats. This suggests that two closely related coronaviruses may circulate in little brown bats. Sequence variation among coronavirus detected from individual bats suggested that infection occurred prior to hibernation, and that the virus persisted for up to 4 months of hibernation in the laboratory. Based on the sequence of its genome, the coronavirus was placed in the Alphacoronavirus genus, along with some human coronaviruses, bat viruses and the porcine epidemic diarrhoea virus. The detection and identification of an apparently persistent coronavirus in a local bat species creates opportunities to understand the dynamics of coronavirus circulation in bat populations.

Human Endogenous Retrovirus-K and TDP-43 Expression Bridges ALS and HIV Neuropathology.

Abstract: Despite the repetitive association of endogenous retroviruses in human disease, the mechanisms behind their pathological contributions remain to be resolved. Here we discuss how neuronal human endogenous retrovirus-K (HERV-K) expression in human immunodeficiency virus (HIV)-infected individuals is a distinct pathological aspect of HIV-associated neurological conditions, such as HIV encephalitis and HIV-associated neurocognitive disorders. Enhanced neuronal HERV-K levels were observed in the majority of HIV-infected individuals, and to a higher degree in brain tissue marked by HIV replication. Moreover, we highlight an important neuropathological overlap between amyotrophic lateral sclerosis and HIV encephalitis, that being the formation of neurotoxic TDP-43 deposits in neurons. Herein, we argue for enhanced transdisciplinary research in the field of ERV biology, using an example of how HERV-K expression has novel mechanistic and therapeutic implications for HIV neuropathology.

Collective cell migration has distinct directionality and speed dynamics

Abstract: When a constraint is removed, confluent cells migrate directionally into the available space. How the migration directionality and speed increase are initiated at the leading edge and propagate into neighboring cells are not well understood. Using a quantitative visualization technique-Particle Image Velocimetry (PIV)-we revealed that migration directionality and speed had strikingly different dynamics. Migration directionality increases as a wave propagating from the leading edge into the cell sheet, while the increase in cell migration speed is maintained only at the leading edge. The overall directionality steadily increases with time as cells migrate into the cell-free space, but migration speed remains largely the same. A particle-based compass (PBC) model suggests cellular interplay (which depends on cell-cell distance) and migration speed are sufficient to capture the dynamics of migration directionality revealed experimentally. Extracellular Ca2+ regulated both migration speed and directionality, but in a significantly different way, suggested by the correlation between directionality and speed only in some dynamic ranges. Our experimental and modeling results reveal distinct directionality and speed dynamics in collective migration, and these factors can be regulated by extracellular Ca2+ through cellular interplay. Quantitative visualization using PIV and our PBC model thus provide a powerful approach to dissect the mechanisms of collective cell migration.

Surveillance of environmental movements in Canada: critical infrastructure protection and the petro-security apparatus

Abstract: A convergence of post-9/11 security governance practices and a dependence on extractive economies has resulted in changes to the way Canadian policing agencies classify environmental movements. We detail how the category of ‘critical infrastructure protection’ (CIP) now enables surveillance of environmentalists under the banner of national security. We examine the growth of CIP as a security category, its changing character from the Cold War to the present, and the role of threat entrepreneurs. We demonstrate that CIP networks have institutionalized collaborations between national security agencies and energy corporations, creating a petro-security apparatus that aims to suppress dissent. We conclude with reflections on what surveillance regimes driven by the petro-security apparatus mean for debates about national security and social movements.