search
Include:
The following results are related to Canada. Are you interested to view more results? Visit OpenAIRE - Explore.
972 Research products, page 1 of 98

  • Canada
  • AR
  • CONICET Digital

10
arrow_drop_down
Relevance
arrow_drop_down
  • Restricted
    Authors: 
    A. Mederos; David F. Kelton; Andrew S. Peregrine; John A. VanLeeuwen; S. Fernández; A. LeBoeuf; Paula I. Menzies; Ralph C. Martin;
    Publisher: Elsevier BV
    Country: Argentina
    Project: NSERC

    A study was conducted in sheep on Canadian farms to describe the relationship between packed cell volume (PCV) or fecal egg counts (FEC) and subjective clinical parameters that may indicate the severity of parasitic gastroenteritis. Twenty-one farms in Ontario (ON) and 8 farms in Quebec (QC) were purposively selected and visited during April–May (spring) and August (summer) 2007. At each farm visit, blood and fecal samples were collected from 10 ewes and 10 female lambs; body condition score (BCS), dag score (DS), fecal consistency score (FCS) and FAMACHA score were recorded for all sampled sheep. Packed cell volume was determined for all blood samples, and FEC were performed for all fecal samples. Summary statistics and simple correlations were performed for the parameters recorded. Two mixed models with random effects at the farm level were developed; one using PCV as the response variable and another using the natural log of eggs per gram of feces (lnEPG). Finally, the residuals from both models were correlated to the covariates in the models. The mean PCV values during the spring were 29.7% and 36.7% for lambs, and 28.8% and 31.1% for ewes, in ON and QC, respectively. During the summer, the mean PCV was 32.0% and 32.8% for lambs, and 30.1% and 29.9% for ewes, in ON and QC, respectively. The arithmetic mean FEC per gram of feces (EPG) during the spring was 3 and 2 for lambs, and 1266 and 789 for ewes, in ON and QC, respectively, whereas during summer the arithmetic mean EPG was 907 and 237 for lambs, and 458 and 246 for ewes, in ON and QC, respectively. Results from simple correlations indicated that PCV was negatively correlated with lnEPG (r = −0.255; r2 = 6.5%) and FAMACHA (r = −0.312; r2 = 9.7%), and positively correlated with BCS (r = 0.317; r2 = 10%). LnEPG was negatively correlated with BCS (r = −0.232; r2 = 5.4%) and PCV (r = −0.255; r2 = 6.5%), but positively correlated with FAMACHA (r = 0.178; r2 = 3.2%) and DS (r = 0.086; r2 = 0.7%). Results from the models indicated that PCV and lnEPG residuals were negatively correlated with FAMACHA, FCS and almost all categories of BCS and DS, although the correlations were very low. The main results from this study suggested that none of the subjective clinical parameters evaluated were highly correlated with PCV or lnEPG and therefore were not good predictors of lnEPG or PCV on the studied farms in Ontario and Quebec. Fil: Mederos, A.. Instituto Nacional de Investigación Agropecuaria; Uruguay Fil: Kelton, D.. University of Guelph; Canadá Fil: Peregrine, A. S.. University of Guelph; Canadá Fil: VanLeeuwen, J.. University Of Prince Edward Island; Canadá Fil: Fernández, Alicia Silvina. University of Guelph; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: LeBoeuf, A.. Ministère de l’Agriculture, des Pêcheries et de l’Alimentation du Québec; Canadá Fil: Menzies, P.. University of Guelph; Canadá Fil: Martin, R.. Nova Scotia Agricultural College; Canadá

  • Restricted
    Authors: 
    Mariano A. Rodriguez-Cabal; M. Noelia Barrios-Garcia; Seth M. Rudman; Athena D. McKown; Takuya Sato; Gregory M. Crutsinger;
    Publisher: Wiley
    Country: Argentina
    Project: NSERC

    Phenology, or the timing of life cycle events, is a key trait of organisms that has significance for how communities are assembled and ecosystems function. Although variation in phenology in plants has received increased attention over the past decade as a result of changing climate, we are only beginning to understand the role of genetic variation in these phenological traits on ecological interactions and ecosystem-level processes. The influence of tree species on riparian environments presents an interesting system for understanding the effects of phenology in terrestrial species on aquatic ecosystems. Here, we used a dominant riparian tree (Populus trichocarpa: Salicaceae) and tested intraspecific genetic variation in the phenological timing of leaf drop, which influenced leaf-litter inputs into our experimental aquatic ecosystems. Our empirical results found that genotypic differences in P. trichocarpa explained much of the variation both in leaf-litter decomposition and aquatic invertebrate species richness within our experimental ponds. Moreover, our results showed that variation in the timing of leaf-litter inputs outweighed the effects of variation in leaf-litter quality among P. trichocarpa genotypes on aquatic invertebrate species richness. Taken together, our results suggest that genetic variation in the timing of litter inputs from dominant plant species is likely to be a strong underlying mechanism driving litter decomposition and invertebrate communities in aquatic ecosystems. This emphasises that studies disregarding phenology may significantly underestimate an important and variable component in communities and ecosystems. Fil: Rodriguez Cabal, Mariano Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. University of British Columbia; Canadá Fil: Barrios Garcia Moar, Maria Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of British Columbia; Canadá. Administración de Parques Nacionales. Parque Nacional "Nahuel Huapi"; Argentina Fil: Rudman, Seth M.. University of British Columbia; Canadá Fil: McKown, Athena D.. University of British Columbia; Canadá Fil: Sato, Takuya. Kobe University; Japón Fil: Crutsinger, Gregory M.. University of British Columbia; Canadá

  • Open Access
    Authors: 
    Sylvester, Francisco; Kalaci, Odion; Leung, Brian; Lacoursière Roussel, Anaïs; Murray, Cathryn Clarke; Choi, Francis M.; Bravo, Monica A.; Therriault, Thomas W.; MacIsaac, Hugh J.;
    Publisher: Scholarship at UWindsor
    Countries: Canada, Argentina

    1. The most effective way to manage nonindigenous species and their impacts is to prevent their introduction via vector regulation. While ships' ballast water is very well studied and this vector is actively managed, hull fouling has received far less attention and regulations are only now being considered despite its importance for introductions to coastal, marine systems. 2. We conducted comprehensive in situ sampling and video recording of hulls of 40 transoceanic vessels to assess propagule and colonization pressure in Vancouver and Halifax, dominant coastal ports in Canada. Concomitant sampling was conducted of harbour fouling communities to compare hull and port communities as part of a vector risk assessment. 3. Although this vector has been operational for a long time, hull and harbour communities were highly divergent, with mean Sørensen's similarity values of 0·03 in Halifax and 0·01 in Vancouver, suggesting invasion risk is high. Propagule pressure (up to 600 000 ind. ship-1) and colonization pressure (up to 156 species ship-1) were high and varied significantly between ports, with Vancouver receiving much higher abundances and diversity of potential invaders. The higher risk of fouling introductions in Vancouver is consistent with historical patterns of successful hull fouling invasions. 4. The extent of hull fouling was modelled using ship history predictors. Propagule pressure increased with time spent in previous ports-of-call and time since last application of antifouling paint, whereas colonization pressure increased with time since last painting and with the number of regions visited by the ship. Both propagule and colonization pressure were negatively related to the time spent at sea and the latitude of ports visited. 5. Synthesis and applications. A major challenge for applied invasion ecology is the effective management of introduction vectors. We found that hull fouling has a strong potential for introduction of many species to coastal marine habitats and that management should be considered. Simple variables related to the vessels' hull husbandry, voyage, and sailing patterns may be used to predict and manage hull fouling intensity. The results presented here should interest policy makers and environmental managers who seek to reduce invasion risk, and ship owners seeking to optimize fuel efficiency. Fil: Sylvester, Francisco. University of Windsor. Great Lakes Institute for Enviromental Research; Canadá. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Kalaci, Odion. University of Windsor. Great Lakes Institute for Enviromental Research; Canadá Fil: Leung, Brian. McGill University; Canadá Fil: Lacoursière Roussel, Anaïs. McGill University; Canadá Fil: Murray, Cathryn Clarke. University of British Columbia; Canadá Fil: Choi, Francis M.. University of British Columbia; Canadá Fil: Bravo, Monica A.. Fisheries and Oceans Canada; Canadá Fil: Therriault, Thomas W.. Fisheries and Oceans Canada; Canadá Fil: MacIsaac, Hugh J.. University of Windsor. Great Lakes Institute for Enviromental Research; Canadá

  • Open Access
    Authors: 
    Kecia A. Kerr; Anabell J. Cornejo; Frédéric Guichard; Augusto Cesar Crespi Abril; Rachel Collin;
    Publisher: Oxford University Press (OUP)
    Country: Argentina

    Predation is considered an important source of mortality for plankton, but documenting variation in planktonic predation, particularly across interacting environmental cycles, remains logistically difficult, thus our understanding remains limited. To test for the combined effects of prey life history stage, diel or light level phase (including crepuscular periods) and seasonal upwelling on the risk of predation, we deployed tethered adult and larval brine shrimp Artemia franciscana using dock-based plankton tethering units (PTUs). Risk was higher overall during upwelling, but life history stage also interacted with season. There was no seasonal difference in risk for adults. Larvae were at significantly lower risk of predation during non-upwelling than during upwelling. Larvae were also at lower risk during non-upwelling than were adults during either season. During upwelling, there was no significant difference in risk between the two prey categories. With respect to the diel cycle, dusk was safer than daytime. For larvae, the diel pattern in risk remained consistent across seasons while risk for adults at night was slightly lower during upwelling than during non-upwelling. Variation in planktonic predation risk across diel and seasonal cycles differs for different life history stages and thus, generalizations fail to capture the complexity of interactions between factors. Fil: Kerr, Kecia A.. Mc Gill University; Canadá. Instituto Smithsonian de Investigaciones Tropicales; Panamá Fil: Cornejo, Anabell. Instituto Smithsonian de Investigaciones Tropicales; Panamá. Universitat Bremen; Alemania Fil: Guichard, Frédéric. Mc Gill University; Canadá Fil: Crespi Abril, Augusto Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina Fil: Collin, Rachel. Instituto Smithsonian de Investigaciones Tropicales; Panamá. Mc Gill University; Canadá

  • Restricted English
    Authors: 
    Cristian Vodopivez; Antonio Curtosi; Edda C. Villaamil; Patricia Smichowski; Émilien Pelletier; Walter P. Mac Cormack;
    Publisher: Elsevier Science
    Country: Argentina
    Project: EC | IMCONET (318718)

    Studies on metal contamination in 25 de Mayo Island, Antarctica, yielded controversial results. In this work, we analyzed Antarctic marine sediments and Antarctic clam (Laternula elliptica) tissues to investigate the possible use of this mollusk as a biomonitor of metals and to identify the sources of metal pollution. Different types of paint from several buildings from Carlini Station were examined to assess their contribution to the local and random metal pollution. Five sediment samples, 105 L. elliptica specimens (40.2-78.0mm length) and four types of paint were analyzed to quantify Cd, Cr, Cu, Fe, Mn, Pb and Zn using inductively coupled plasma-optical emission spectrometry. Metal concentrations in sediments were lower than the global averages of the earth's crust, with the exception of Cd and Cu. These results were related to the contribution of the local fresh-water runoff. The different varieties of paint showed low levels of Cu, Mn, Fe and Zn, whereas a broad range of values were found in the case of Cr and Pb (20-15,100μg·g-1 and 153-115,500μg·g-1 respectively). The remains of the paint would be responsible for the significant increases in Cr and Pb which are randomly detected by us and by other authors. High levels of Fe and Cd, in comparison to other Antarctic areas, appear to be related to the terrigenous materials transported by the local streams. Accumulation indexes suggested that kidney tissue from L. elliptica could be an adequate material for biomonitoring pollution with Cd, Zn and probably also Pb. In general, relationships between size and metal contents reported by other authors were not verified, suggesting that this issue should be revised. elliptica could be adequate for biomonitoring pollution with Cd and Zn. Fil: Vodopivez, Leopoldo Cristian. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina Fil: Curtosi, Antonio. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina Fil: Villaamil Lepori, Edda Cristina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina Fil: Smichowski, Patricia Nora. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Pelletier, Emilien. Université du Québec à Rimouski; Canadá Fil: Mac Cormack, Walter Patricio. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Nanobiotecnología. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Nanobiotecnología; Argentina

  • Open Access English
    Authors: 
    Clément Pellegrin; Yohann Daguerre; Joske Ruytinx; Frederic Guinet; Minna Kemppainen; Nicolas Frei dit Frey; Virginie Puech-Pagès; Arnaud Hecker; Alejandro Guillermo Pardo; Francis Martin; +1 more
    Publisher: HAL CCSD
    Countries: Belgium, Argentina, France, France
    Project: NSERC

    The ectomycorrhizal symbiosis is a predominant tree–microbe interaction in forest ecosystems sustaining tree growth and health. Its establishment and functioning implies a long‐term and intimate relationship between the soil‐borne fungi and the roots of trees. Mycorrhiza‐induced Small‐Secreted Proteins (MiSSPs) are hypothesized as keystone symbiotic proteins, required to set up the symbiosis by modifying the host metabolism and/or building the symbiotic interfaces. L. bicolor MiSSP8 is the third most highly induced MiSSPs in symbiotic tissues and it is also expressed in fruiting bodies. The MiSSP8‐RNAi knockdown mutants are strongly impaired in their mycorrhization ability with Populus, with the lack of fungal mantle and Hartig net development due to the lack of hyphal aggregation. MiSSP8 C‐terminus displays a repetitive motif containing a kexin cleavage site, recognized by KEX2 in vitro. This suggests MiSSP8 protein might be cleaved into small peptides. Moreover, the MiSSP8 repetitive motif is found in other proteins predicted secreted by both saprotrophic and ectomycorrhizal fungi. Thus, our data indicate that MiSSP8 is a small‐secreted protein involved at early stages of ectomycorrhizal symbiosis, likely by regulating hyphal aggregation and pseudoparenchyma formation. Fil: Pellegrin, Clément. université de Lorraine; Francia Fil: Pellegrin, Clément. Fil: Ruytinx, Joske. Fil: Guinet, Frédéric. Fil: Kemppainen, Minna. Fil: Frei dit Frey, Nicolas. Fil: Puech Pagès, Virginie. Fil: Hecker, Arnaud. Fil: Pardo, Alejandro Guillermo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Micología Molecular; Argentina Fil: Martin, Francis M.. Fil: Veneault Fourrey, Claire.

  • Open Access English
    Authors: 
    Diego Armentano; Carlos Beltrán; Michael Shub;
    Publisher: American Mathematical Society
    Countries: Spain, Argentina

    We prove that points in the sphere associated with roots of random polynomials via the stereographic projection, are surprisignly well-suited with respect to the minimal logarithmic energy on the sphere. That is, roots of random polynomials provide a fairly good approximation to Elliptic Fekete points. Fil: Armentano, Diego. Universidad de la República; Uruguay Fil: Beltran, Carlos. Universidad de Cantabria; España Fil: Shub, Michael Ira. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Investigaciones Matemáticas "Luis A. Santaló"; Argentina. University Of Toronto; Canadá

  • Open Access
    Authors: 
    M.F. Silva-Barni; Mariana Gonzalez; Frank Wania; Y.D. Lei; Karina S.B. Miglioranza;
    Publisher: Elsevier BV
    Country: Argentina

    XAD-resin based passive air samplers were deployed at 10 sites in the Quequén Grande River watershed in Argentina during three periods to evaluate the spatial and temporal variations of pesticides and PCBs in the atmosphere. Endosulfan and chlorpyrifos were the most prevalent pesticide because of their continued usage in Argentina, while DDTs, HCHs, chlordanes, dieldrin and heptachlors registered lower levels, reflecting their use in the past. Atmospheric endosulfan levels were 1-2 orders of magnitude higher during the application period (application: 800-12,000 pg/m3, pre- and post-application: <2-350 pg/m3), suggesting that its use in the area continued even after a ban came into effect. The remaining organochlorine pesticides also reached higher concentrations during this period, which is more likely attributable to temperature controlled air-surface exchange than current applications. The highest concentrations of chlorpyrifos were recorded during the application period, in particular at agricultural sites, where its use is wide-spread on soybean fields. The fungicide chlorothalonil was found predominantly at urban sites and in proximity to Quequén harbor, suggesting that its use might be domestic and as a biocide in antifouling paints. A different temporal pattern was observed for the herbicide trifluralin, suggesting its use in the early stages of the wheat-growing season during winter. Limited spatial variations in PCBs levels indicate a diffuse contamination source in the study area, while their relatively high correlation with temperature suggests re-volatilization from local sources. Relative enrichment of lighter PCBs congeners could be attributed to re-evaporation from secondary sources as well as atmospheric transport from urban sites. Fil: Silva Barni, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Gonzalez, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Wania, F.. University of Toronto; Canadá Fil: Lei, Y.D.. University of Toronto; Canadá Fil: Miglioranza, Karina Silvia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

  • Open Access English
    Authors: 
    Romina Elizabeth Araya; María Florencia Gómez Castro; Paula Carasi; Justin L. McCarville; Jennifer Jury; Allan McI. Mowat; Elena F. Verdu; Fernando Gabriel Chirdo;
    Publisher: American Physiological Society
    Countries: United Kingdom, Argentina, Argentina
    Project: CIHR

    Celiac disease (CD) is an immune-mediated enteropathy triggered by gluten in genetically susceptible individuals. Innate immunity contributes to the pathogenesis of CD, but the mechanisms remain poorly understood. Although previous in vitro work suggests that gliadin peptide p31-43 acts as an innate immune trigger, the underlying pathways are unclear and have not been explored in vivo. Here we show that intraluminal delivery of p31-43 induces morphological changes in the small intestinal mucosa of normal mice consistent with those seen in CD, including increased cell death and expression of inflammatory mediators. The effects of p31-43 were dependent on MyD88 and type I IFNs, but not Toll-like receptor 4 (TLR4), and were enhanced by coadministration of the TLR3 agonist polyinosinic:polycytidylic acid. Together, these results indicate that gliadin peptide p31-43 activates the innate immune pathways in vivo, such as IFN-dependent inflammation, relevant to CD. Our findings also suggest a common mechanism for the potential interaction between dietary gluten and viral infections in the pathogenesis of CD. Instituto de Estudios Inmunológicos y Fisiopatológicos

  • Open Access English
    Authors: 
    Dena W. McMartin; Bruno H. Hernani Merino; Barrie Bonsal; Margot Hurlbert; Ricardo Villalba; Olga L. Ocampo; Jorge Julián Vélez Upegui; Germán Poveda; David J. Sauchyn;
    Publisher: Springer
    Country: Argentina
    Project: CIHR

    Debate and deliberation surrounding climate change has shifted from mitigation toward adaptation, with much of the adaptation focus centered on adaptive practices, and infrastructure development. However, there is little research assessing expected impacts, potential benefits, and design challenges that exist for reducing vulnerability to expected climate impacts. The uncertainty of design requirements and associated government policies, and social structures that reflect observed and projected changes in the intensity, duration, and frequency of water-related climate events leaves communities vulnerable to the negative impacts of potential flood and drought. The results of international research into how agricultural infrastructure features in current and planned adaptive capacity of rural communities in Argentina, Canada, and Colombia indicate that extreme hydroclimatic events, as well as climate variability and unpredictability are important for understanding and responding to community vulnerability. The research outcomes clearly identify the need to deliberately plan, coordinate, and implement infrastructures that support community resiliency. Fil: McMartin, Dena W.. University of Regina; Canadá Fil: Hernani Merino, Bruno H.. University of Regina; Canadá Fil: Bonsal, Barrie. Environment Canada; Canadá Fil: Hurlbert, Margot. University of Regina; Canadá Fil: Villalba, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Cientifícas y Tecnológicas; Argentina Fil: Ocampo, Olga L.. Universidad Autónoma de Manizales; Colombia Fil: Upegui, Jorge Julián Vélez. Universidad Nacional de Colombia; Colombia Fil: Poveda, Germán. Universidad Nacional de Colombia; Colombia Fil: Sauchyn, David J.. University of Regina; Canadá

search
Include:
The following results are related to Canada. Are you interested to view more results? Visit OpenAIRE - Explore.
972 Research products, page 1 of 98
  • Restricted
    Authors: 
    A. Mederos; David F. Kelton; Andrew S. Peregrine; John A. VanLeeuwen; S. Fernández; A. LeBoeuf; Paula I. Menzies; Ralph C. Martin;
    Publisher: Elsevier BV
    Country: Argentina
    Project: NSERC

    A study was conducted in sheep on Canadian farms to describe the relationship between packed cell volume (PCV) or fecal egg counts (FEC) and subjective clinical parameters that may indicate the severity of parasitic gastroenteritis. Twenty-one farms in Ontario (ON) and 8 farms in Quebec (QC) were purposively selected and visited during April–May (spring) and August (summer) 2007. At each farm visit, blood and fecal samples were collected from 10 ewes and 10 female lambs; body condition score (BCS), dag score (DS), fecal consistency score (FCS) and FAMACHA score were recorded for all sampled sheep. Packed cell volume was determined for all blood samples, and FEC were performed for all fecal samples. Summary statistics and simple correlations were performed for the parameters recorded. Two mixed models with random effects at the farm level were developed; one using PCV as the response variable and another using the natural log of eggs per gram of feces (lnEPG). Finally, the residuals from both models were correlated to the covariates in the models. The mean PCV values during the spring were 29.7% and 36.7% for lambs, and 28.8% and 31.1% for ewes, in ON and QC, respectively. During the summer, the mean PCV was 32.0% and 32.8% for lambs, and 30.1% and 29.9% for ewes, in ON and QC, respectively. The arithmetic mean FEC per gram of feces (EPG) during the spring was 3 and 2 for lambs, and 1266 and 789 for ewes, in ON and QC, respectively, whereas during summer the arithmetic mean EPG was 907 and 237 for lambs, and 458 and 246 for ewes, in ON and QC, respectively. Results from simple correlations indicated that PCV was negatively correlated with lnEPG (r = −0.255; r2 = 6.5%) and FAMACHA (r = −0.312; r2 = 9.7%), and positively correlated with BCS (r = 0.317; r2 = 10%). LnEPG was negatively correlated with BCS (r = −0.232; r2 = 5.4%) and PCV (r = −0.255; r2 = 6.5%), but positively correlated with FAMACHA (r = 0.178; r2 = 3.2%) and DS (r = 0.086; r2 = 0.7%). Results from the models indicated that PCV and lnEPG residuals were negatively correlated with FAMACHA, FCS and almost all categories of BCS and DS, although the correlations were very low. The main results from this study suggested that none of the subjective clinical parameters evaluated were highly correlated with PCV or lnEPG and therefore were not good predictors of lnEPG or PCV on the studied farms in Ontario and Quebec. Fil: Mederos, A.. Instituto Nacional de Investigación Agropecuaria; Uruguay Fil: Kelton, D.. University of Guelph; Canadá Fil: Peregrine, A. S.. University of Guelph; Canadá Fil: VanLeeuwen, J.. University Of Prince Edward Island; Canadá Fil: Fernández, Alicia Silvina. University of Guelph; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: LeBoeuf, A.. Ministère de l’Agriculture, des Pêcheries et de l’Alimentation du Québec; Canadá Fil: Menzies, P.. University of Guelph; Canadá Fil: Martin, R.. Nova Scotia Agricultural College; Canadá

  • Restricted
    Authors: 
    Mariano A. Rodriguez-Cabal; M. Noelia Barrios-Garcia; Seth M. Rudman; Athena D. McKown; Takuya Sato; Gregory M. Crutsinger;
    Publisher: Wiley
    Country: Argentina
    Project: NSERC

    Phenology, or the timing of life cycle events, is a key trait of organisms that has significance for how communities are assembled and ecosystems function. Although variation in phenology in plants has received increased attention over the past decade as a result of changing climate, we are only beginning to understand the role of genetic variation in these phenological traits on ecological interactions and ecosystem-level processes. The influence of tree species on riparian environments presents an interesting system for understanding the effects of phenology in terrestrial species on aquatic ecosystems. Here, we used a dominant riparian tree (Populus trichocarpa: Salicaceae) and tested intraspecific genetic variation in the phenological timing of leaf drop, which influenced leaf-litter inputs into our experimental aquatic ecosystems. Our empirical results found that genotypic differences in P. trichocarpa explained much of the variation both in leaf-litter decomposition and aquatic invertebrate species richness within our experimental ponds. Moreover, our results showed that variation in the timing of leaf-litter inputs outweighed the effects of variation in leaf-litter quality among P. trichocarpa genotypes on aquatic invertebrate species richness. Taken together, our results suggest that genetic variation in the timing of litter inputs from dominant plant species is likely to be a strong underlying mechanism driving litter decomposition and invertebrate communities in aquatic ecosystems. This emphasises that studies disregarding phenology may significantly underestimate an important and variable component in communities and ecosystems. Fil: Rodriguez Cabal, Mariano Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. University of British Columbia; Canadá Fil: Barrios Garcia Moar, Maria Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of British Columbia; Canadá. Administración de Parques Nacionales. Parque Nacional "Nahuel Huapi"; Argentina Fil: Rudman, Seth M.. University of British Columbia; Canadá Fil: McKown, Athena D.. University of British Columbia; Canadá Fil: Sato, Takuya. Kobe University; Japón Fil: Crutsinger, Gregory M.. University of British Columbia; Canadá

  • Open Access
    Authors: 
    Sylvester, Francisco; Kalaci, Odion; Leung, Brian; Lacoursière Roussel, Anaïs; Murray, Cathryn Clarke; Choi, Francis M.; Bravo, Monica A.; Therriault, Thomas W.; MacIsaac, Hugh J.;
    Publisher: Scholarship at UWindsor
    Countries: Canada, Argentina

    1. The most effective way to manage nonindigenous species and their impacts is to prevent their introduction via vector regulation. While ships' ballast water is very well studied and this vector is actively managed, hull fouling has received far less attention and regulations are only now being considered despite its importance for introductions to coastal, marine systems. 2. We conducted comprehensive in situ sampling and video recording of hulls of 40 transoceanic vessels to assess propagule and colonization pressure in Vancouver and Halifax, dominant coastal ports in Canada. Concomitant sampling was conducted of harbour fouling communities to compare hull and port communities as part of a vector risk assessment. 3. Although this vector has been operational for a long time, hull and harbour communities were highly divergent, with mean Sørensen's similarity values of 0·03 in Halifax and 0·01 in Vancouver, suggesting invasion risk is high. Propagule pressure (up to 600 000 ind. ship-1) and colonization pressure (up to 156 species ship-1) were high and varied significantly between ports, with Vancouver receiving much higher abundances and diversity of potential invaders. The higher risk of fouling introductions in Vancouver is consistent with historical patterns of successful hull fouling invasions. 4. The extent of hull fouling was modelled using ship history predictors. Propagule pressure increased with time spent in previous ports-of-call and time since last application of antifouling paint, whereas colonization pressure increased with time since last painting and with the number of regions visited by the ship. Both propagule and colonization pressure were negatively related to the time spent at sea and the latitude of ports visited. 5. Synthesis and applications. A major challenge for applied invasion ecology is the effective management of introduction vectors. We found that hull fouling has a strong potential for introduction of many species to coastal marine habitats and that management should be considered. Simple variables related to the vessels' hull husbandry, voyage, and sailing patterns may be used to predict and manage hull fouling intensity. The results presented here should interest policy makers and environmental managers who seek to reduce invasion risk, and ship owners seeking to optimize fuel efficiency. Fil: Sylvester, Francisco. University of Windsor. Great Lakes Institute for Enviromental Research; Canadá. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Kalaci, Odion. University of Windsor. Great Lakes Institute for Enviromental Research; Canadá Fil: Leung, Brian. McGill University; Canadá Fil: Lacoursière Roussel, Anaïs. McGill University; Canadá Fil: Murray, Cathryn Clarke. University of British Columbia; Canadá Fil: Choi, Francis M.. University of British Columbia; Canadá Fil: Bravo, Monica A.. Fisheries and Oceans Canada; Canadá Fil: Therriault, Thomas W.. Fisheries and Oceans Canada; Canadá Fil: MacIsaac, Hugh J.. University of Windsor. Great Lakes Institute for Enviromental Research; Canadá

  • Open Access
    Authors: 
    Kecia A. Kerr; Anabell J. Cornejo; Frédéric Guichard; Augusto Cesar Crespi Abril; Rachel Collin;
    Publisher: Oxford University Press (OUP)
    Country: Argentina

    Predation is considered an important source of mortality for plankton, but documenting variation in planktonic predation, particularly across interacting environmental cycles, remains logistically difficult, thus our understanding remains limited. To test for the combined effects of prey life history stage, diel or light level phase (including crepuscular periods) and seasonal upwelling on the risk of predation, we deployed tethered adult and larval brine shrimp Artemia franciscana using dock-based plankton tethering units (PTUs). Risk was higher overall during upwelling, but life history stage also interacted with season. There was no seasonal difference in risk for adults. Larvae were at significantly lower risk of predation during non-upwelling than during upwelling. Larvae were also at lower risk during non-upwelling than were adults during either season. During upwelling, there was no significant difference in risk between the two prey categories. With respect to the diel cycle, dusk was safer than daytime. For larvae, the diel pattern in risk remained consistent across seasons while risk for adults at night was slightly lower during upwelling than during non-upwelling. Variation in planktonic predation risk across diel and seasonal cycles differs for different life history stages and thus, generalizations fail to capture the complexity of interactions between factors. Fil: Kerr, Kecia A.. Mc Gill University; Canadá. Instituto Smithsonian de Investigaciones Tropicales; Panamá Fil: Cornejo, Anabell. Instituto Smithsonian de Investigaciones Tropicales; Panamá. Universitat Bremen; Alemania Fil: Guichard, Frédéric. Mc Gill University; Canadá Fil: Crespi Abril, Augusto Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina Fil: Collin, Rachel. Instituto Smithsonian de Investigaciones Tropicales; Panamá. Mc Gill University; Canadá

  • Restricted English
    Authors: 
    Cristian Vodopivez; Antonio Curtosi; Edda C. Villaamil; Patricia Smichowski; Émilien Pelletier; Walter P. Mac Cormack;
    Publisher: Elsevier Science
    Country: Argentina
    Project: EC | IMCONET (318718)

    Studies on metal contamination in 25 de Mayo Island, Antarctica, yielded controversial results. In this work, we analyzed Antarctic marine sediments and Antarctic clam (Laternula elliptica) tissues to investigate the possible use of this mollusk as a biomonitor of metals and to identify the sources of metal pollution. Different types of paint from several buildings from Carlini Station were examined to assess their contribution to the local and random metal pollution. Five sediment samples, 105 L. elliptica specimens (40.2-78.0mm length) and four types of paint were analyzed to quantify Cd, Cr, Cu, Fe, Mn, Pb and Zn using inductively coupled plasma-optical emission spectrometry. Metal concentrations in sediments were lower than the global averages of the earth's crust, with the exception of Cd and Cu. These results were related to the contribution of the local fresh-water runoff. The different varieties of paint showed low levels of Cu, Mn, Fe and Zn, whereas a broad range of values were found in the case of Cr and Pb (20-15,100μg·g-1 and 153-115,500μg·g-1 respectively). The remains of the paint would be responsible for the significant increases in Cr and Pb which are randomly detected by us and by other authors. High levels of Fe and Cd, in comparison to other Antarctic areas, appear to be related to the terrigenous materials transported by the local streams. Accumulation indexes suggested that kidney tissue from L. elliptica could be an adequate material for biomonitoring pollution with Cd, Zn and probably also Pb. In general, relationships between size and metal contents reported by other authors were not verified, suggesting that this issue should be revised. elliptica could be adequate for biomonitoring pollution with Cd and Zn. Fil: Vodopivez, Leopoldo Cristian. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina Fil: Curtosi, Antonio. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina Fil: Villaamil Lepori, Edda Cristina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina Fil: Smichowski, Patricia Nora. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Pelletier, Emilien. Université du Québec à Rimouski; Canadá Fil: Mac Cormack, Walter Patricio. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Nanobiotecnología. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Nanobiotecnología; Argentina

  • Open Access English
    Authors: 
    Clément Pellegrin; Yohann Daguerre; Joske Ruytinx; Frederic Guinet; Minna Kemppainen; Nicolas Frei dit Frey; Virginie Puech-Pagès; Arnaud Hecker; Alejandro Guillermo Pardo; Francis Martin; +1 more
    Publisher: HAL CCSD
    Countries: Belgium, Argentina, France, France
    Project: NSERC

    The ectomycorrhizal symbiosis is a predominant tree–microbe interaction in forest ecosystems sustaining tree growth and health. Its establishment and functioning implies a long‐term and intimate relationship between the soil‐borne fungi and the roots of trees. Mycorrhiza‐induced Small‐Secreted Proteins (MiSSPs) are hypothesized as keystone symbiotic proteins, required to set up the symbiosis by modifying the host metabolism and/or building the symbiotic interfaces. L. bicolor MiSSP8 is the third most highly induced MiSSPs in symbiotic tissues and it is also expressed in fruiting bodies. The MiSSP8‐RNAi knockdown mutants are strongly impaired in their mycorrhization ability with Populus, with the lack of fungal mantle and Hartig net development due to the lack of hyphal aggregation. MiSSP8 C‐terminus displays a repetitive motif containing a kexin cleavage site, recognized by KEX2 in vitro. This suggests MiSSP8 protein might be cleaved into small peptides. Moreover, the MiSSP8 repetitive motif is found in other proteins predicted secreted by both saprotrophic and ectomycorrhizal fungi. Thus, our data indicate that MiSSP8 is a small‐secreted protein involved at early stages of ectomycorrhizal symbiosis, likely by regulating hyphal aggregation and pseudoparenchyma formation. Fil: Pellegrin, Clément. université de Lorraine; Francia Fil: Pellegrin, Clément. Fil: Ruytinx, Joske. Fil: Guinet, Frédéric. Fil: Kemppainen, Minna. Fil: Frei dit Frey, Nicolas. Fil: Puech Pagès, Virginie. Fil: Hecker, Arnaud. Fil: Pardo, Alejandro Guillermo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Micología Molecular; Argentina Fil: Martin, Francis M.. Fil: Veneault Fourrey, Claire.

  • Open Access English
    Authors: 
    Diego Armentano; Carlos Beltrán; Michael Shub;
    Publisher: American Mathematical Society
    Countries: Spain, Argentina

    We prove that points in the sphere associated with roots of random polynomials via the stereographic projection, are surprisignly well-suited with respect to the minimal logarithmic energy on the sphere. That is, roots of random polynomials provide a fairly good approximation to Elliptic Fekete points. Fil: Armentano, Diego. Universidad de la República; Uruguay Fil: Beltran, Carlos. Universidad de Cantabria; España Fil: Shub, Michael Ira. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Investigaciones Matemáticas "Luis A. Santaló"; Argentina. University Of Toronto; Canadá

  • Open Access
    Authors: 
    M.F. Silva-Barni; Mariana Gonzalez; Frank Wania; Y.D. Lei; Karina S.B. Miglioranza;
    Publisher: Elsevier BV
    Country: Argentina

    XAD-resin based passive air samplers were deployed at 10 sites in the Quequén Grande River watershed in Argentina during three periods to evaluate the spatial and temporal variations of pesticides and PCBs in the atmosphere. Endosulfan and chlorpyrifos were the most prevalent pesticide because of their continued usage in Argentina, while DDTs, HCHs, chlordanes, dieldrin and heptachlors registered lower levels, reflecting their use in the past. Atmospheric endosulfan levels were 1-2 orders of magnitude higher during the application period (application: 800-12,000 pg/m3, pre- and post-application: <2-350 pg/m3), suggesting that its use in the area continued even after a ban came into effect. The remaining organochlorine pesticides also reached higher concentrations during this period, which is more likely attributable to temperature controlled air-surface exchange than current applications. The highest concentrations of chlorpyrifos were recorded during the application period, in particular at agricultural sites, where its use is wide-spread on soybean fields. The fungicide chlorothalonil was found predominantly at urban sites and in proximity to Quequén harbor, suggesting that its use might be domestic and as a biocide in antifouling paints. A different temporal pattern was observed for the herbicide trifluralin, suggesting its use in the early stages of the wheat-growing season during winter. Limited spatial variations in PCBs levels indicate a diffuse contamination source in the study area, while their relatively high correlation with temperature suggests re-volatilization from local sources. Relative enrichment of lighter PCBs congeners could be attributed to re-evaporation from secondary sources as well as atmospheric transport from urban sites. Fil: Silva Barni, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Gonzalez, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Wania, F.. University of Toronto; Canadá Fil: Lei, Y.D.. University of Toronto; Canadá Fil: Miglioranza, Karina Silvia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

  • Open Access English
    Authors: 
    Romina Elizabeth Araya; María Florencia Gómez Castro; Paula Carasi; Justin L. McCarville; Jennifer Jury; Allan McI. Mowat; Elena F. Verdu; Fernando Gabriel Chirdo;
    Publisher: American Physiological Society
    Countries: United Kingdom, Argentina, Argentina
    Project: CIHR

    Celiac disease (CD) is an immune-mediated enteropathy triggered by gluten in genetically susceptible individuals. Innate immunity contributes to the pathogenesis of CD, but the mechanisms remain poorly understood. Although previous in vitro work suggests that gliadin peptide p31-43 acts as an innate immune trigger, the underlying pathways are unclear and have not been explored in vivo. Here we show that intraluminal delivery of p31-43 induces morphological changes in the small intestinal mucosa of normal mice consistent with those seen in CD, including increased cell death and expression of inflammatory mediators. The effects of p31-43 were dependent on MyD88 and type I IFNs, but not Toll-like receptor 4 (TLR4), and were enhanced by coadministration of the TLR3 agonist polyinosinic:polycytidylic acid. Together, these results indicate that gliadin peptide p31-43 activates the innate immune pathways in vivo, such as IFN-dependent inflammation, relevant to CD. Our findings also suggest a common mechanism for the potential interaction between dietary gluten and viral infections in the pathogenesis of CD. Instituto de Estudios Inmunológicos y Fisiopatológicos

  • Open Access English
    Authors: 
    Dena W. McMartin; Bruno H. Hernani Merino; Barrie Bonsal; Margot Hurlbert; Ricardo Villalba; Olga L. Ocampo; Jorge Julián Vélez Upegui; Germán Poveda; David J. Sauchyn;
    Publisher: Springer
    Country: Argentina
    Project: CIHR

    Debate and deliberation surrounding climate change has shifted from mitigation toward adaptation, with much of the adaptation focus centered on adaptive practices, and infrastructure development. However, there is little research assessing expected impacts, potential benefits, and design challenges that exist for reducing vulnerability to expected climate impacts. The uncertainty of design requirements and associated government policies, and social structures that reflect observed and projected changes in the intensity, duration, and frequency of water-related climate events leaves communities vulnerable to the negative impacts of potential flood and drought. The results of international research into how agricultural infrastructure features in current and planned adaptive capacity of rural communities in Argentina, Canada, and Colombia indicate that extreme hydroclimatic events, as well as climate variability and unpredictability are important for understanding and responding to community vulnerability. The research outcomes clearly identify the need to deliberately plan, coordinate, and implement infrastructures that support community resiliency. Fil: McMartin, Dena W.. University of Regina; Canadá Fil: Hernani Merino, Bruno H.. University of Regina; Canadá Fil: Bonsal, Barrie. Environment Canada; Canadá Fil: Hurlbert, Margot. University of Regina; Canadá Fil: Villalba, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Cientifícas y Tecnológicas; Argentina Fil: Ocampo, Olga L.. Universidad Autónoma de Manizales; Colombia Fil: Upegui, Jorge Julián Vélez. Universidad Nacional de Colombia; Colombia Fil: Poveda, Germán. Universidad Nacional de Colombia; Colombia Fil: Sauchyn, David J.. University of Regina; Canadá