Paléoécologie des environnements nordiques anthropisés : une étude comparative entre l'Islande et le Labrador

Dans le but de comparer l’impact des fluctuations climatiques et des activités anthropiques sur l'évolution du couvert végétal des environnements nordiques avant et après leur anthropisation, une étude paléoécologique basée sur une approche pluridisciplinaire a été réalisée sur des échantillons prélevés aux alentours de sites archéologiques au nord-est de l’Islande et au nord du Labrador. Les bio-indicateurs qui ont été utilisés incluent les grains de pollen, les macrorestes (plantes et insectes), les diatomées et les cernes de croissance d’arbres. Le Labrador a été occupé par des groupes autochtones depuis 7000 ans; leur économie de subsistance était basée sur la chasse, la pêche et la cueillette de petits fruits. En Islande, la première vague de colons scandinaves est arrivée à la fin du 9e siècle; ils ont apporté avec eux un mode de vie européen continental basé sur un système de subsistance combinant l'agriculture, l’élevage et la pêche. Tant en Islande qu’au Labrador, nos données paléoenvironnementales montrent une évolution de la végétation similaire qui a été principalement influencée par les conditions climatiques qui prévalaient. À titre d’exemple, la détérioration des conditions environnementales au cours du Néoglaciaire a entrainé un déclin du couvert forestier en faveur des arbustes et des espèces de tourbières. Dans les deux régions d’étude, l'effet principal de l'activité anthropique a été l'introduction et la dispersion de nouvelles espèces de mauvaises herbes et des déchets reliés à leurs activités quotidiennes. Toutefois, au Labrador, l’arrivée des Moraves vers AD 1771 semble avoir entrainé l’ouverture du couvert forestier le long de la côte. En combinant les données paléoenvironnementales et archéologiques, nous avons démontré que les les Inuits et les Moraves du Labrador et les Norois en Islande ont dû faire face à des fluctuations climatiques similaires au cours des derniers millénaires. En particulier, les Norois auraient mis en œuvre des stratégies de gestion des terres pour développer les pâturages à partir de AD 940 et même pendant la période du Petit Âge glaciaire. Pour les Inuits du Labrador, les changements dans l'évolution du paysage sont subtils jusqu’à la fin du 18e siècle, ce qui coïncide avec l'arrivée des missionnaires moraves en 1771. Le besoin récurrent en bois a causé l’ouverture du couvert forestier ce qui pourrait avoir conduit à l'établissement du mélèze.The aim of this study is to compare the impact of climatic fluctuations and anthropogenic activities on the evolution of vegetation cover in anthropic northern environments. Paleoecological studies based on a multi-proxy approach were undertaken on samples taken from archeological sites located in northeastern Iceland and northern Labrador. The fundamental bio-indicators included pollen, macrofossils (plants and insects), diatoms and tree-rings growth. Labrador has been occupied by aboriginal groups for 7000 years BP. Their subsistence economy was based on hunting, fishing and gathering berry picking. In Iceland, the first wave of Norse settlers arrived at the end of the 9th Century. They brought with them a continental European way of life based on a subsistence system combining pasture and fisheries. The paleoenvironmental data in Iceland and Labrador show a similar vegetation evolution that was mainly influenced by prevailing climate conditions. For example, the deterioration of environmental conditions during the Neoglacial led to a decline in forest cover in favor of shrubs and peatland species. In both of the study regions, the main effects of anthropogenic activity were the introduction and dispersal of new weed species and waste disposal related to their daily activities. However, in Labrador, the arrival of the Moravians at around 1771 seems to have led the opening of the forest cover along the coast. By combining palaeoenvironmental and archaeological data, we have shown that the Inuit and Moravians in Labrador and the Norse in Iceland faced similar climatic fluctuations over the last millennium. In Iceland, the Norse settlers implemented major land management strategies to develop pasture land, which is the primary reason they continued to occupy Svalbard since AD 940 and during the Little Ice Age. In Labrador, there were subtle changes in the landscape at the end of the 18th Century that coincided with the arrival of the Moravian missionaries. In particular, the recurrent need for wood caused an opening in the spruce forest that could have led to the establishment of tamarack

Induction of human immunodeficiency virus type 1-specific T cells by a bluetongue virus tubule-vectored vaccine prime-recombinant modified virus Ankara boost regimen.

In the absence of strategies for reliable induction of antibodies broadly neutralizing human immunodeficiency virus type 1 (HIV-1), vaccine efforts have shifted toward the induction of cell-mediated immunity. Here we describe the construction and immunogenicity of novel T-cell vaccine NS1.HIVA, which delivers the HIV-1 clade A consensus-derived immunogen HIVA on the surface of tubular structures spontaneously formed by protein NS1 of bluetongue virus. We demonstrated that NS1 tubules can accommodate a protein as large as 527 amino acids without losing their self-assembly capability. When injected into BALB/c mice by several routes, chimeric NS1.HIVA tubules induced HIV-1-specific major histocompatibility complex class I-restricted T cells. These could be boosted by modified virus Ankara expressing the same immunogen and generate a memory capable of gamma interferon (IFN-gamma) production, proliferation, and lysis of sensitized target cells. Induced memory T cells readily produced IFN-gamma 230 days postimmunization, and upon a surrogate virus challenge, NS1.HIVA vaccine alone decreased the vaccinia virus vv.HIVA load in ovaries by 2 orders of magnitude 280 days after immunization. Thus, because of its T-cell immunogenicity and antigenic simplicity, the NS1 delivery system could serve as a priming agent for heterologous prime-boost vaccination regimens. Its usefulness in primates, including humans, remains to be determined

Is the HCV-HIV co-infection prevalence amongst injecting drug users a marker for the level of sexual and injection related HIV transmission?

BACKGROUND: Amongst injecting drug users (IDUs), HIV is transmitted sexually and parenterally, but HCV is transmitted primarily parenterally. We assess and model the antibody prevalence of HCV amongst HIV-infected IDUs (denoted as HCV-HIV co-infection prevalence) and consider whether it proxies the degree of sexual HIV transmission amongst IDUs. METHODS: HIV, HCV and HCV-HIV co-infection prevalence data amongst IDU was reviewed. An HIV/HCV transmission model was adapted. Multivariate model uncertainty analyses determined whether the model's ability to replicate observed data trends required the inclusion of sexual HIV transmission. The correlation between the model's HCV-HIV co-infection prevalence and estimated proportion of HIV infections due to injecting was evaluated. RESULTS: The median HCV-HIV co-infection prevalence (prevalence of HCV amongst HIV-infected IDUs) was 90% across 195 estimates from 43 countries. High HCV-HIV co-infection prevalences (>80%) occur in most (75%) settings, but can be lower in settings with low HIV prevalence (0.75). The model without sexual HIV transmission reproduced some data trends but could not reproduce any epidemics with high HIV/HCV prevalence ratios (>0.85) or low HCV-HIV co-infection prevalence (10%. The model with sexual HIV transmission reproduced data trends more closely. The proportion of HIV infections due to injecting correlated with HCV-HIV co-infection prevalence; suggesting that up to 80/60/90%. CONCLUSION: Substantial sexual HIV transmission may occur in many IDU populations; HCV-HIV co-infection prevalence could signify its importance

Adolescent girls’ infant and young child nutrition knowledge sources differ among urban and rural samples in Bangladesh

Background: In many low-income countries, including in Bangladesh, girls tend to marry early and have children very soon after marriage. Although conveying infant and young child nutrition (IYCN) knowledge to adolescent girls in a timely manner is important to ensure the well-being of their children, little is known about the best ways to convey these messages. Objective: This study examines the sources from which adolescent girls derive IYCN knowledge in order to inform the design of programs that convey such information. Methods: Information on both characteristics and IYCN knowledge of adolescent girls aged 12-18 was collected as part of a baseline survey in 2013 for the DFID Programme to Accelerate Improved Nutrition for the Extreme Poor in Bangladesh project. A total of 436 girls in rural areas and 345 girls in urban areas are present in the study. Data were analyzed using ordinary least squares (OLS) regression, fixed effects regression, and Poisson regression models. Results: In both the urban and rural samples, girls’ schooling is positively and significantly associated with IYCN knowledge. IYCN knowledge of adolescent girls’ mothers is also associated with adolescents’ IYCN knowledge in both urban and rural samples, but the magnitude of association in the urban sample is only half that of the rural sample. Conclusions: In Bangladesh, efforts to improve knowledge regarding IYCN is typically focused on mothers of young children. Only some of this knowledge is passed onto adolescent girls living in the same household. As other messaging efforts directed towards mothers have only small, or no association with adolescent girls’ knowledge of IYCN, improving adolescent girls’ understanding of breastfeeding, complementary feeding and more general nutrition knowledge may require information and messaging specifically directed towards them

Adolescent girls’ infant and young child nutrition knowledge sources differ among urban and rural samples in Bangladesh

Background: In many low-income countries, including in Bangladesh, girls tend to marry early and have children very soon after marriage. Although conveying infant and young child nutrition (IYCN) knowledge to adolescent girls in a timely manner is important to ensure the well-being of their children, little is known about the best ways to convey these messages. Objective: This study examines the sources from which adolescent girls derive IYCN knowledge in order to inform the design of programs that convey such information. Methods: Information on both characteristics and IYCN knowledge of adolescent girls aged 12-18 was collected as part of a baseline survey in 2013 for the DFID Programme to Accelerate Improved Nutrition for the Extreme Poor in Bangladesh project. A total of 436 girls in rural areas and 345 girls in urban areas are present in the study. Data were analyzed using ordinary least squares (OLS) regression, fixed effects regression, and Poisson regression models. Results: In both the urban and rural samples, girls’ schooling is positively and significantly associated with IYCN knowledge. IYCN knowledge of adolescent girls’ mothers is also associated with adolescents’ IYCN knowledge in both urban and rural samples, but the magnitude of association in the urban sample is only half that of the rural sample. Conclusions: In Bangladesh, efforts to improve knowledge regarding IYCN is typically focused on mothers of young children. Only some of this knowledge is passed onto adolescent girls living in the same household. As other messaging efforts directed towards mothers have only small, or no association with adolescent girls’ knowledge of IYCN, improving adolescent girls’ understanding of breastfeeding, complementary feeding and more general nutrition knowledge may require information and messaging specifically directed towards them

Defining the "core microbiome" of the microbial communities in the tonsils of healthy pigs

BACKGROUND: Porcine tonsils are the colonization site for many pathogenic as well as commensal microorganisms and are the primary lymphoid tissue encountered by organisms entering through the mouth or nares. The goal of this study was to provide an in-depth characterization of the composition and structure of the tonsillar microbial communities and to define the core microbiome in the tonsils of healthy pigs, using high throughput bar-coded 454-FLX pyrosequencing. RESULTS: Whole tonsils were collected at necropsy from 12 16-week-old finisher pigs from two healthy herds. Tonsil brushes were also used to collect samples from four of these animals. Bacterial DNA was isolated from each sample, amplified by PCR with universal primers specific for the bacterial 16S rRNA genes, and the PCR products sequenced using pyrosequencing. An average of 13,000 sequences were generated from each sample. Microbial community members were identified by sequence comparison to known bacterial 16S rRNA gene sequences. The microbiomes of these healthy herds showed very strong similarities in the major components as well as distinct differences in minor components. Pasteurellaceae dominated the tonsillar microbiome in all animals, comprising ~60% of the total, although the relative proportions of the genera Actinobacillus, Haemophilus, and Pasteurella varied between the herds. Also found in all animals were the genera Alkanindiges, Peptostreptococcus, Veillonella, Streptococcus and Fusobacterium, as well as Enterobacteriaceae and Neisseriaceae. Treponema and Chlamydia were unique to Herd 1, while Arcanobacterium was unique to Herd 2. Tonsil brushes yielded similar results to tissue specimens, although Enterobacteriaceae and obligate anaerobes were more frequently found in tissue than in brush samples, and Chlamydia, an obligately intracellular organism, was not found in brush specimens. CONCLUSIONS: We have extended and supported our previous studies with 16S clone libraries, using 16S rRNA gene pyrosequencing to describe the microbial communities in tonsils of healthy pigs. We have defined a core microbiome, dominated by Pasteurellaceae, in tonsil specimens, and have also demonstrated the presence of unique minor components of the tonsillar microbiome present in each herd. We have validated the use of noninvasive tonsil brushes, in comparison to tonsil tissue, which will facilitate future studies.Beth A. Lowe, Terence L. Marsh, Natasha Isaacs-Cosgrove, Roy N. Kirkwood, Matti Kiupel and Martha H. Mulk

Urban Forest and the Tree Canopy: A Pathway to Climate Resilience

Background: Urban ecosystems face many environmental, infrastructure, and social systems challenges. Urban forest plays an important role in urban ecology but continue to face many direct and indirect threats. Research indicates that climate change, insects, disease, and urbanization are the major causes of urban forest decline. Tree canopies play a major role in ecosystem services, providing the advantages of a natural, cost-effective system of green infrastructure, removal of air and water pollutants, modulation of energy use, and improvement in water quality. These services increase climate resilience. Purpose: The purpose of this service-learning project was to gain a better understanding of ecosystem service benefits from trees in Washington, DC and whether these benefits facilitated Washington, DC being more climate resilient. Our aim was two-folds, to describe the monetary value of carbon sequestration from trees in DC, and to assist in identifying tree species in local neighborhoods. Methods: We collected tree canopy data using the i-Tree tool designed to provide an estimate of ecosystem service benefits and the TreeSnap tool designed to allow citizen scientists to make observations of trees in local communities and provide pictorial documents to scientists who catalog tree species. Results: Our results showed on average carbon sequestered by trees valued at $10,196,999 million dollars and carbon stored in trees was valued at$256,084,907 million dollars. Our other results showed the variety of tree species such as the Japanese Cherry Tree, have large bases, are plentiful throughout Washington, DC, and capable of storing large amounts of carbon. Conclusion: Washington, DC has increased the number of trees planted annually, which we believe creates a pathway to a climate-resilient city. As urban sustainability majors, this project enlightened our understanding of urban sustainability and climate resilience

Incarceration history and risk of HIV and hepatitis C virus acquisition among people who inject drugs: a systematic review and meta-analysis

Background People who inject drugs (PWID) experience a high prevalence of incarceration and might be at high risk of HIV and hepatitis C virus (HCV) infection during or after incarceration. We aimed to assess whether incarceration history elevates HIV or HCV acquisition risk among PWID. Methods In this systematic review and meta-analysis, we searched MEDLINE, Embase, and PsycINFO databases for studies in any language published from Jan 1, 2000 until June 13, 2017 assessing HIV or HCV incidence among PWID. We included studies that measured HIV or HCV incidence among community-recruited PWID. We included only studies reporting original results and excluded studies that evaluated incident infections by self-report. We contacted authors of cohort studies that met the inclusion or exclusion criteria, but that did not report on the outcomes of interest, to request data. We extracted and pooled data from the included studies using random-effects meta-analyses to quantify the associations between recent (past 3, 6, or 12 months or since last follow-up) or past incarceration and HIV or HCV acquisition (primary infection or reinfection) risk among PWID. We assessed the risk of bias of included studies using the Newcastle-Ottawa Scale. Between-study heterogeneity was evaluated using the I2 statistic and the P-value for heterogeneity. Findings We included published results from 20 studies and unpublished results from 21 studies. These studies originated from Australasia, western and eastern Europe, North and Latin America, and east and southeast Asia. Recent incarceration was associated with an 81% (relative risk [RR] 1·81, 95% CI 1·40–2·34) increase in HIV acquisition risk, with moderate heterogeneity between studies (I2=63·5%; p=0·001), and a 62% (RR 1·62, 95% CI 1·28–2·05) increase in HCV acquisition risk, also with moderate heterogeneity between studies (I2=57·3%; p=0·002). Past incarceration was associated with a 25% increase in HIV (RR 1·25, 95% CI 0·94–1·65) and a 21% increase in HCV (1·21, 1·02–1·43) acquisition risk. Interpretation Incarceration is associated with substantial short-term increases in HIV and HCV acquisition risk among PWID and could be a significant driver of HCV and HIV transmission among PWID. These findings support the need for developing novel interventions to minimise the risk of HCV and HIV acquisition, including addressing structural risks associated with drug laws and excessive incarceration of PWID