Mature trees help to offset urban area problems caused by impervious pavement. Trees in paved areas remain unhealthy due to a poor root zone environment. The objective of this experiment was to test if soil under pervious concrete, with greater water and gas infiltration, would be more beneficial to existing mature trees during urban development. Root activity, root growth and soil chemistry of American sweetgum under standard concrete, pervious concrete and no concrete were measured. Soil CO2 efflux rates and soil CO2 concentrations were extremely high under both concrete treatments. Soil under standard concrete had lower oxygen concentrations than soil under pervious concrete and control treatments, particularly under wet conditions. There was no pavement effect on soil water content or soil chemistry. Under control treatment standing live root length was greater than under both concrete treatments. There were no major differences in soil conditions between impervious and pervious concrete treatments. The soil under the plots, a Ships clay, with very low permeability may have prevented soil water infiltration. Likely this overrode any potential treatment effects due to porosity of the concrete. To obtain root zone benefits out of pervious concrete, a different base soil with a higher permeability would be a better alternative.

Trade openness, market size, transparency, ease of doing business, location advantagesand low levels of corruption and country risk are the main determinants that attractForeign Direct Investment into a host country. FDI inflows in México have increasedremarkably since 1994 when the North America Free Trade Agreement (NAFTA) cameinto effect. Using multiple regression analysis in order to measure the impact of FDI onGDP; the Empirical results showed that a one percent increase in FDI leads on average toan increase of 0.08 percent in GDP which clearly reflects a positive but neither animportant nor a substantial impact of FDI on economic growth in México as it would beexpected. Time series data analysis for the period 1980-2007 has been tested for UnitRoot by applying the Dickey-Fuller (DF) test. Each time series after the first differencebecomes stationary and therefore it might be a causal relationship among the variables.However, FDI will not have a real impact on the society unless there is an effective stockof Human Capital capable of learning and absorbing the know-how to work successfullywith the technology that Multinational Corporations bring into the host country with theirinvestment. The challenge for the Mexican Government is to create structural reformssuch as the deregulation of energy and oil sector for private investment that will lead toconstantly higher flows of FDI. In the medium term this will then be reflected in thesociety in terms of poverty reduction and development of its population.

Abstract The main objective of our paper is to investigate whether expansion in exports can lead to improve economic growth of Sub-Saharan African countries for the period 1970-2006. Four macro economic indicators (real GDP, Trade balance, Government expenditure and Investment) are used in our model to carry out our analysis concerning Sub Saharan African countries. Time series techniques such as unit root test (Augmented Dickey Fuller test) and co integration test (Johansen’s procedure) are used to find out whether there is a long run relationship between economic growth and trade balance. The results of the unit root test indicate that all series are stationary after first difference, with I (1). Johansen’s co integration test showed that co integration (long run relationship) exists between GDP and Trade balance, as we got significant eigenvalues and found co integration between all of the four variables which shows that they are co integrated with each other and indicates a long run relationship. Our results indicate that for the time period of 1970 to 2006, Sub Saharan African countries experienced a simultaneous increase in economic growth and trade balance as well as in investment and Govt expenditure.   Key words: exports, economic growth, unit root, co integration, Sub-Saharan Africa

Plant growth-promoting rhizobacteria (PGPR) are free-living, soil-borne bacteria that colonize the rhizosphere and, when applied to crops, enhance the growth of plants. Plant growth-promoting rhizobacteria may enhance plant growth either by direct or indirect mechanisms. The direct mechanisms of action include nitrogen fixation,production of phytohormones and lowering of ethylene concentrations. The objective of this study was to determine whether Pseudomonas putida strain 6-8 isolated from the rhizosphere of legume crops grown in Saskatchewan fields was able to promote the growth of canola cv. Smart and lentil cv. Milestone plants by direct mechanisms. Initial studies determined the effect of strain 6-8 and other known phytohormoneproducing PGPR strains on the growth of canola and lentil plants both in gnotobiotic and growth chamber conditions. Variations in the results were observed, as there were significant differences among trials. Strain 6-8 enhanced the growth of canola cv. Smart in growth pouches but not in pots in growth chamber studies. In the case of lentil cv.Milestone, strain 6-8 had no significant effect in growth pouches, but it significantly increased root dry weight, shoot dry weight and root surface area in pots in growth chamber studies. A similar effect was observed with wild-type strains GR12-2 and G20- 18. Strain GR12-2 was consistent in promoting the growth of lentil cv. Milestone both in growth pouches and in pots in growth chambers when compared to other strains and the control. The ability of the PGPR strains to produce auxin and cytokinin phytohomones in pure culture and in the canola rhizosphere was tested using the enzyme linked immunosorbent assay (ELISA). All the PGPR strains produced indole compounds and the concentration of the indoles produced increased with increasing concentrations of the precursor tryptophan. There were no significant differences among PGPR strains in production of indole-3-acetic acid (IAA) when assayed using ELISA. The concentrations of IAA secreted by PGPR strains were extremely low (0.19 µg/ml 9.80 µg/ml). Strain 6-8 produced the cytokinins, isopentenyl adenosine (IPA), zeatin riboside (ZR) and dihydroxyzeatin riboside (DHZR) in pure culture. Indole-3-acetic acid was detected in supernatants obtained from canola growth pouches inoculated with PGPR strains, but there were no significant differences in the concentrations of IAA secreted among PGPR strains. Significantly higher concentrations of IPA and ZR were observed in the rhizosphere of canola inoculated with strain 6-8 than in the non-inoculated control. Strain 6-8 produced siderophores, solubilized inorganic phosphate and used 1-aminocyclopropane-1-carboxylic acid (ACC), the precursor of ethylene, as sole nitrogen source. These traits are considered to be alternative mechanisms for direct plant growth promotion. A qualitative and quantitative study of root colonization by strain 6-8 was conducted by tagging the strain with green fluorescent protein in conjunction with confocal laser scanning microscopy and by conventional plating. The populations of strain 6-8 were higher on canola roots than on lentil roots by conventional plating. Similar results were also observed in confocal laser scanning microscopy (CLSM) studies after 5, 7 and 9 days for canola and 3, 6 and 9 days for lentil. Pseudomonas putida strain 6-8 produced cytokinins and also possessed other direct growth promoting characteristics. The ability of strain 6-8 to promote the growth of canola cv. Smart in growth pouches and lentil cv. Milestone in growth chamber studies may be related to these direct growth promoting characteristics. Strain 6-8 may have potential for development as a plant growth-promoting rhizobacterial inoculant.

Purpose: This retrospective study was performed to assess the clinical and radiographic success rates of a non-vital formocresol and zinc oxide eugenol (ZOE) primary molar root canal therapy (RCT) technique. The effects of this treatment on the permanent successors and on exfoliation times were also investigated. Methods: The study included 161 patients with 211 primary molars treated by RCT by a single operator in a private pediatric dental office in the Toronto area. Results: A clinical success rate of 90.0% and a radiographic success rate of 77.3% were obtained. Enamel defects were found in 6.8% of permanent successors and in patients who were significantly younger at the time of root canal therapy treatment (p = .001). Treated molars exfoliated on average 5.8 months sooner than contralateral teeth (p<0.001). Conclusions: Formocresol and ZOE RCT is a viable treatment for necrotic primary molars and yielded very high clinical success rates with moderate radiographic success rates.

This study examined the use of phage therapy against Pseudomonas aeruginosa strain PA14 biofilms. Part 1: 24 and 96h PA14 biofilms grown in microplates were phage treated and bacterial biomass was quantified using crystal violet staining. Part 2: 24 and 96h PA14 biofilms grown in prepared root canals of human mandibular incisors were treated with phages and intra-canal samples using paper points and round burs were taken to assess phage and bacterial counts. Part 1: Two phages (JBD4 and JBD44a) were used. Treatment with phages produced significant reduction in the mean percentage of biomass in 24h (p<0.05) and 96h (p=0.08) biofilms. Part 2: In 24 and 96h biofilms in a root canal model, no significant difference was found in colony forming units after phage treatment (p>0.05). Phage application significantly reduced the biomass of 24 and 96h PA14 biofilms grown on microplates, but did not in the extracted tooth models.

Purpose: This retrospective study was performed to assess the clinical and radiographic success rates of a non-vital formocresol and zinc oxide eugenol (ZOE) primary molar root canal therapy (RCT) technique. The effects of this treatment on the permanent successors and on exfoliation times were also investigated. Methods: The study included 161 patients with 211 primary molars treated by RCT by a single operator in a private pediatric dental office in the Toronto area. Results: A clinical success rate of 90.0% and a radiographic success rate of 77.3% were obtained. Enamel defects were found in 6.8% of permanent successors and in patients who were significantly younger at the time of root canal therapy treatment (p = .001). Treated molars exfoliated on average 5.8 months sooner than contralateral teeth (p<0.001). Conclusions: Formocresol and ZOE RCT is a viable treatment for necrotic primary molars and yielded very high clinical success rates with moderate radiographic success rates.

This study examined the use of phage therapy against Pseudomonas aeruginosa strain PA14 biofilms. Part 1: 24 and 96h PA14 biofilms grown in microplates were phage treated and bacterial biomass was quantified using crystal violet staining. Part 2: 24 and 96h PA14 biofilms grown in prepared root canals of human mandibular incisors were treated with phages and intra-canal samples using paper points and round burs were taken to assess phage and bacterial counts. Part 1: Two phages (JBD4 and JBD44a) were used. Treatment with phages produced significant reduction in the mean percentage of biomass in 24h (p<0.05) and 96h (p=0.08) biofilms. Part 2: In 24 and 96h biofilms in a root canal model, no significant difference was found in colony forming units after phage treatment (p>0.05). Phage application significantly reduced the biomass of 24 and 96h PA14 biofilms grown on microplates, but did not in the extracted tooth models.

The development of plants challenged by environmental stress alters plant architecture through several pathways, including those involving plant hormone responses and reactive oxygen species (ROS) production. Auxin, a phytohormone associated with every aspect of development, and abscisic acid (ABA), a phytohormone involved in abiotic stress responses, both interact with ROS. These ROS are used as secondary messengers to activate transcription of abiotic stress genes, and also in developmental responses such as cell elongation. To understand the mechanisms involved in the abiotic stress response and how the response intersects with auxin, ABA, and ROS, I examined COPPER INDUCED IN LEAVES 1 (<i>CIL1</i>) from <i>Brassica carinata</i> and its Arabidopsis orthologue, AUXIN INDUCED IN ROOTS 12 (AIR12). Expression of both genes increases in response to auxin and recent work has placed both <i>CIL1</i> and AIR12 within a family of plant-specific cytochrome b561 proteins thought to be involved with transmission of ROS signals. This suggests a link between auxin and ROS production resulting from abiotic stress. Antisense <i>CIL1 B. carinata</i> plants produced fewer lateral roots and were resistant to salinity stress during vegetative growth. Mutant air12 plants showed a 50% reduction in lateral root number, lateral root length, and H2O2 root distribution. Growth in the presence of H2O2 was able to restore lateral root length to control levels. In silica analysis of the <i>CIL1</i> and AIR12 amino acid sequences detected an attachment site for glucosylphosphatidylinositol, predicting that the protein is targeted to the extracellular leaflet of the plasma membrane where it could be cleaved and released into the apoplast. Subcellular localization using p35S::GFP-CIL1 and p35S::GFP-AIR12 translational fusions confirmed that CIL1 and AIR12 localize to the plasma membrane and are released into the apoplast. Organ localization of AIR12 using the pAIR12::GFP-AIR12 construct in stably transformed Arabidopsis showed fusion protein accumulation in the apex of the primary root and in the vascular tissue. Fusion protein also localized to cells flanking emerging lateral roots. Investigation of pAIR12::GUS Arabidopsis showed GUS accumulation in the apex of elongating lateral roots. I demonstrate that AIR12 is an extracellular protein and that air12 seedlings are susceptible to salt stress, but not osmostic stress and display increased and decreased sensitivity to ABA during germination and primary root elongation, respectively, suggesting that AIR12 acts downstream of abiotic stress recognition.

<i>Pseudomonas fluorescens</i> BRG100 produces secondary metabolites with herbicidal activity to the grass weeds wild oat, Avena fatua, and green foxtail, Setaria viridis. The green fluorescence protein (gfp) gene was introduced into P. fluorescens BRG100 from Escherichia coli S17-1¥ë via a Tn5 mini transposon suicide vector system. Colony morphology, growth rate in liquid media, weed biocontrol efficacy (plant growth pouch), carbon utilization (Biolog GN) and root colonization of green foxtail by several P. fluorescens BRG100gfp transformants were determined to be the same as the wild type. <i>Pseudomonas fluorescens</i> BRGgfp-15 was found to be most similar to the wild-type in all of the above characteristics and was thus used in subsequent experiments. Note: all strains of Pseudomonas fluorescens will be referred to by only their strain throughout (ie. BRGgfp-15 and BRG100). <p>It was determined by population dynamics per section of root with spiral plating on culture medium, epi-fluorescence and confocal microscopy that BRGgfp-15 colonized all areas of the root, but showed a preference for the proximal 1/3 section and the seed. In the proximal section the mean number of viable cells per gram dry weight was log109.06 and log109.31, when applied as liquid inoculum and as the pesta granular formulation, respectively. With liquid inoculum there was only log107.53 viable cells/g in the middle 1/3 section and log107.01 viable cells/g in the distal 1/3 section. The number of viable cells/g with pesta granules was log107.61 and log107.34, for the middle and distal sections, respectively. The root hairs, root tip, and ventral portion of the seed were all areas of heavy colonization relative to the other areas of the root. <p>Survival of BRGgfp-15 in the pesta formulation was examined in 2 soil types, clay and clay loam, in a thermogradient plate apparatus by a factorial randomized design complete block experiment. The experiment included: 3-12 hour diurnal temperature regimes: 5-15¨¬C, 15-25¨¬C, and 25-35¨¬C and 3 moisture levels: 25, 50 and 75% of soil moisture holding capacity. Sampling was carried out after 0, 14, 28 and 42 days. The highest numbers of viable BRGgfp-15 cells/g were found in the pesta granules in soil subjected to the lowest diurnal temperature regime and moisture content. The lowest numbers of viable cells/g were found in the pesta granules incubated in the highest diurnal temperature and moisture. This suggests lower soil temperature and moisture enhances survival of BRGgfp-15 in pesta and/ or higher soil temperature and moisture enhances the release and dissemination of BRGgfp-15 from pesta granules. When subjected to a 5-15¨¬C-temperature regime the number of viable cells/g was log109.80. When subjected to 15-25¨¬C the viable cells/g was log108.96 and with 25-35¨¬C it was log107.33. The mean number of viable cells/g was log109.36, log108.86, and log107.87, for 25, 50, and 75% soil moisture holding capacity, respectively. There was also a significantly higher number of viable cells/g in the clay soil collected from Saskatoon, log109.00, as compared to the clay loam soil collected from Scott, which was log108.40. <p>These results suggest that Pseudomonas fluorescens BRG100 has considerable potential as a bioherbicide because of its successful root colonization of green foxtail and wheat. <i>Pseudomonas fluorescens</i> BRGgfp-15 survived well under various environmental conditions when formulated into pesta granules, proving the pesta formulation was an excellent formulation. In addition, gfp was shown to be an excellent conservative marker for monitoring the root colonization and survival of <i>P. fluorescens</i> BRG100.