Influence of tectonics on the extent of quaternary glaciation in the Andes

The extent of Quaternary glaciations varies throughout the Andes. Although the lack of radiometric dating in many places precludes precise assessment of these variations, certain spatial patterns are evident. In the N. Andes (N. of 15ºS) glacial landforms and sediments of only the ultimate and penultimate glaciations (O-isotope stages 2, 4, 6) have been identified. In the Central Andes (15-35ºS) successive glaciations since at least the mid-Quaternary have been progressively less extensive. In the Southern Andes successive glaciations since the greatest glaciation at ca. 1.2 Ma have been progressively smaller; also, the Islas Malvinas 800-1,000 km to the east became glaciated for the first time during the penultimate glaciation and developed an even greater number of nivo-glacial features during the last glaciation. The segmented nature of the oceanic and continental crust along the Pacific-South American subduction zone promotes tectonic independence of parts of the Andean chain. It is argued that variations in the extent of glaciation may be largely explained by Quaternary uplift and subsidence in different places and by precipitation-shadow effects related to elevation and air mass source

Note and Comment

Public Utility Valuations and Rates - In comparing the reports of the public utility commissions with the decisions of the courts on questions of valuation of public utilities, nothing is more striking than this-that as time goes on the commissions are growingly impatient of the cost of reproduction theory, while the courts still insist there is no inflexible method of fixing value, but continue to prefer largely figures as to supposed reproduction cost. This attitude of the commissions is remarkable in view of the fact that every finding may be carried to the courts for review and possible reversal. The Illinois Commission reluctantly obeyed the direct orders of the Supreme Court to consider cost of reproduction, but refuses to treat that as the only basis. Re Springfield Consol. Ry. Co., P. U. R. Ig2o E. 474, 48o. The Interstate Commerce Commission ruled that it was practically impossible for it to find such value in the appraisal of lands of railroads as ordered by Congress in 1912. But the Supreme Court said it must do so because Congress had ordered it. U. S. v. Interstate Coin. Coin., 252 U. S

Influence of pulse crops on arbuscular mycorrhizal fungi in a durum-based cropping system

Non-Peer ReviewedPulses are an important component in crop rotations in southern Saskatchewan. Besides their capability to fix nitrogen, pulse crops establish a symbiotic relationship with arbuscular mycorrhizal fungi, which have been shown to increase nutrient and water uptake through hyphal extensions in the soil. This 2 year study is designed to evaluate the impact of pulses in crop rotations on the biodiversity of AMF communities and their dynamics. Plant N and P uptake and the available soil N and P pools under a durum crop are also measured to assess if there is any correlation with AMF communities. The sampling and analysis is completed on the durum phase of the rotation with preceding crops of pea, lentil, chickpea, canola and durum. The final results will be explained by: (1) the size, nature, and physiological state of the soil microbial community and (2) the nature of the preceding crop residues. Preliminary results from the 2004 season indicate that higher plant P uptake is related to AMF colonization, while no significant change was detected in the soil N and P pools

Contrasting patterns of selection between MHC I and II across populations of Humboldt and Magellanic penguins

The evolutionary and adaptive potential of populations or species facing an emerginginfectious disease depends on their genetic diversity in genes, such as the major histocompatibilitycomplex (MHC). In birds, MHC class I deals predominantly with intracellularinfections (e.g., viruses) and MHC class II with extracellular infections (e.g.,bacteria). Therefore, patterns of MHC I and II diversity may differ between species andacross populations of species depending on the relative effect of local and global environmentalselective pressures, genetic drift, and gene flow. We hypothesize thathigh gene flow among populations of Humboldt and Magellanic penguins limits localadaptation in MHC I and MHC II, and signatures of selection differ between markers,locations, and species. We evaluated the MHC I and II diversity using 454 next-generationsequencing of 100 Humboldt and 75 Magellanic penguins from seven differentbreeding colonies. Higher genetic diversity was observed in MHC I than MHCII for both species, explained by more than one MHC I loci identified. Large populationsizes, high gene flow, and/or similar selection pressures maintain diversity but limitlocal adaptation in MHC I. A pattern of isolation by distance was observed for MHC IIfor Humboldt penguin suggesting local adaptation, mainly on the northernmost studiedlocality. Furthermore, trans-speciesalleles were found due to a recent speciationfor the genus or convergent evolution. High MHC I and MHC II gene diversity describedis extremely advantageous for the long-termsurvival of the species.Fil: Sallaberry Pincheira, Nicole. Pontificia Universidad Católica de Chile; Chile. Universidad Andrés Bello; ChileFil: González Acuña, Daniel. Universidad de Concepción; ChileFil: Padilla, Pamela Solange. Pontificia Universidad Católica de Chile; ChileFil: Dantas, Gisele P. M.. Pontificia Universidade Catolica de Minas Gerais.; BrasilFil: Luna Jorquera, Guillermo. Universidad Católica del Norte; ChileFil: Frere, Esteban. Universidad Nacional de la Patagonia Austral. Unidad Académica Caleta Olivia. Centro de Investigaciones Puerto Deseado; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Valdés Velásquez, Armando. Universidad Peruana Cayetano Heredia; PerúFil: Vianna, Juliana A.. Pontificia Universidad Católica de Chile; Chil

Mitochondrial phylogeography and demographic history of the Vicuña: implications for conservation

The vicuña (Vicugna vicugna; Miller, 1924) is a conservation success story, having recovered from near extinction in the 1960s to current population levels estimated at 275 000. However, lack of information about its demographic history and genetic diversity has limited both our understanding of its recovery and the development of science-based conservation measures. To examine the evolution and recent demographic history of the vicuña across its current range and to assess its genetic variation and population structure, we sequenced mitochondrial DNA from the control region (CR) for 261 individuals from 29 populations across Peru, Chile and Argentina. Our results suggest that populations currently designated as Vicugna vicugna vicugna and Vicugna vicugna mensalis comprise separate mitochondrial lineages. The current population distribution appears to be the result of a recent demographic expansion associated with the last major glacial event of the Pleistocene in the northern (18 to 22°S) dry Andes 14–12 000 years ago and the establishment of an extremely arid belt known as the 'Dry Diagonal' to 29°S. Within the Dry Diagonal, small populations of V. v. vicugna appear to have survived showing the genetic signature of demographic isolation, whereas to the north V. v. mensalis populations underwent a rapid demographic expansion before recent anthropogenic impacts

Traits associated with innate and adaptive immunity in pigs: heritability and associations with performance under different health status conditions

There is a need for genetic markers or biomarkers that can predict resistance towards a wide range of infectious diseases, especially within a health environment typical of commercial farms. Such markers also need to be heritable under these conditions and ideally correlate with commercial performance traits. In this study, we estimated the heritabilities of a wide range of immune traits, as potential biomarkers, and measured their relationship with performance within both specific pathogen-free (SPF) and non-SPF environments. Immune traits were measured in 674 SPF pigs and 606 non-SPF pigs, which were subsets of the populations for which we had performance measurements (average daily gain), viz. 1549 SPF pigs and 1093 non-SPF pigs. Immune traits measured included total and differential white blood cell counts, peripheral blood mononuclear leucocyte (PBML) subsets (CD4+ cells, total CD8α+ cells, classical CD8αβ+ cells, CD11R1+ cells (CD8α+ and CD8α-), B cells, monocytes and CD16+ cells) and acute phase proteins (alpha-1 acid glycoprotein (AGP), haptoglobin, C-reactive protein (CRP) and transthyretin). Nearly all traits tested were heritable regardless of health status, although the heritability estimate for average daily gain was lower under non-SPF conditions. There were also negative genetic correlations between performance and the following immune traits: CD11R1+ cells, monocytes and the acute phase protein AGP. The strength of the association between performance and AGP was not affected by health status. However, negative genetic correlations were only apparent between performance and monocytes under SPF conditions and between performance and CD11R1+ cells under non-SPF conditions. Although we cannot infer causality in these relationships, these results suggest a role for using some immune traits, particularly CD11R1+ cells or AGP concentrations, as predictors of pig performance under the lower health status conditions associated with commercial farms

An improved methodology for the recovery of Zea mays and other large crop pollen, with implications for environmental archaeology in the Neotropics

We present a simple sieving methodology to aid the recovery of large cultigen pollen grains, such as maize (Zea mays L.), manioc (Manihot esculenta Crantz), and sweet potato (Ipomoea batatas L.), among others, for the detection of food production using fossil pollen analysis of lake sediments in the tropical Americas. The new methodology was tested on three large study lakes located next to known and/or excavated pre-Columbian archaeological sites in South and Central America. Five paired samples, one treated by sieving, the other prepared using standard methodology, were compared for each of the three sites. Using the new methodology, chemically digested sediment samples were passed through a 53 µm sieve, and the residue was retained, mounted in silicone oil, and counted for large cultigen pollen grains. The filtrate was mounted and analysed for pollen according to standard palynological procedures. Zea mays (L.) was recovered from the sediments of all three study lakes using the sieving technique, where no cultigen pollen had been previously recorded using the standard methodology. Confidence intervals demonstrate there is no significant difference in pollen assemblages between the sieved versus unsieved samples. Equal numbers of exotic Lycopodium spores added to both the filtrate and residue of the sieved samples allow for direct comparison of cultigen pollen abundance with the standard terrestrial pollen count. Our technique enables the isolation and rapid scanning for maize and other cultigen pollen in lake sediments, which, in conjunction with charcoal and pollen records, is key to determining land-use patterns and the environmental impact of pre-Columbian societies

Barriers and facilitators to implementing community outreach work, and inter-professional collaboration with regional partners

Abstract : Objective. Community outreach workers support individuals in accessing the health and community services they require through various forms of proximity approaches. Even though community outreach has been available in the province of Quebec (Canada) for the past 40 years, it is still difficult to implement and sustain, especially with families of young children. The aim of this study was to document barriers and facilitators to implementing community outreach practices, and to describe how such workers collaborate with sectoral (e.g. health care) and inter-sectoral (e.g. municipalities, community organizations, schools) partners. Methodology. We performed a content analysis on 55 scientific and grey literature documents, and transcriptions of 24 individual interviews and 3 focus groups with stakeholders including parents, community outreach workers, health care employees, and inter-sectoral partners. Results. This study reveals four categories of barriers and facilitators to the implementation of community outreach work (i.e. organizational factors, nature of the work and worker-related factors, family-related factors, external factors). With regards to collaboration, community outreach workers deal with various partners. Good inter-professional collaboration is achieved through positive interactions and communication, shared or co-developed activities for the families, co-intervention with families, and strategies to enhance role awareness and inter-sectoral meetings. Conclusion. Results highlighted that many factors interact and can either influence, positively or negatively, the opportunity to implement community outreach work. The collaborative practices identified may help to maximize facilitators and overcome barriers. Advocacy and a better understanding of how to integrate community outreach work within health services while maintaining the workers’ flexibility are needed to sustain this practice