426 research outputs found

    Plant Isotopes as Indicators of N Cycling Processes in Agricultural Fields

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    When nitrogen (N) availability exceeds biological demand, excess N, especially nitrate (NO3), may subsequently pollute ground and surface water. Agricultural practices in Southern Ontario typically supplement soils with organic and inorganic nutrients to aid in crop development, and employ various management techniques to limit nutrient loss. Excess N has several potential fates, which are controlled by the net effects of numerous N cycling reactions in the soil that are often difficult to measure directly. N cycling in soils is controlled in large part by soil moisture, as it affects microbial activity and soil redox conditions. Stable isotope geochemistry is a powerful tool that provides information on N sources and processes. This study uses crop N and carbon (C) isotope ratios to provide insights into the net effects of soil N cycling and N fate. This research was conducted at the Strawberry Creek Watershed (SCW), an agricultural research watershed located between Kitchener-Waterloo and Guelph, Ontario. A subsequent lab-based grow experiment was conducted at Wilfrid Laurier University in Waterloo, Ontario. The SCW exhibits elevated NO3- concentrations in groundwater, tile discharge, and the stream itself. Previous isotopic work revealed that this NO3-is largely derived from chemical fertilizer and manure applications. Field-scale hydrological processes lead to areas where the fate of applied N differs, which has an isotopic effect on the residual N that is available to plants. Results of this study indicate significant patterns in the isotopic signature of plant tissue, in both temporal and spatial scales. At the plot-scale where soil conditions are similar, there is little to no variation in foliar isotope values, but at the field-scale there appears to be a large amount of variability related to soil moisture and N loss. However, that variability is reduced when soil moisture values are grouped. There exists a significant difference between crop productivity and soil moisture, as the medium moisture range (%VWC 30-40) produced corn yields almost 10% greater than wet (%VWC \u3e40) and dry (%VWC The simulated crop growing experiment provided a simplified and controlled system for investigating the relationship between soil and plants. As the soil from all the barrels came from the same field location, and all N inputs were quantifiable, the differences in foliar δ15N provided meaningful insight into N-cycling. The combination of enriched foliar δ15N and soil N20 production in the relatively wet barrels provides reasonable conclusions about the value of using plant isotopes in the investigation of soil processes. This investigation is critical in furthering the efficiency of N application on crops; as well as, the subsequent decrease in the ecological impacts of farming. Reducing agricultural N leaching to ground and surface water requires a better understanding of N fate in the soil zone, and will result in more effective agricultural nutrient management

    Plant Isotopes as Indicators of N Cycling Processes in Agricultural Fields

    Get PDF
    When nitrogen (N) availability exceeds biological demand, excess N, especially nitrate (NO3), may subsequently pollute ground and surface water. Agricultural practices in Southern Ontario typically supplement soils with organic and inorganic nutrients to aid in crop development, and employ various management techniques to limit nutrient loss. Excess N has several potential fates, which are controlled by the net effects of numerous N cycling reactions in the soil that are often difficult to measure directly. N cycling in soils is controlled in large part by soil moisture, as it affects microbial activity and soil redox conditions. Stable isotope geochemistry is a powerful tool that provides information on N sources and processes. This study uses crop N and carbon (C) isotope ratios to provide insights into the net effects of soil N cycling and N fate. This research was conducted at the Strawberry Creek Watershed (SCW), an agricultural research watershed located between Kitchener-Waterloo and Guelph, Ontario. A subsequent lab-based grow experiment was conducted at Wilfrid Laurier University in Waterloo, Ontario. The SCW exhibits elevated NO3- concentrations in groundwater, tile discharge, and the stream itself. Previous isotopic work revealed that this NO3-is largely derived from chemical fertilizer and manure applications. Field-scale hydrological processes lead to areas where the fate of applied N differs, which has an isotopic effect on the residual N that is available to plants. Results of this study indicate significant patterns in the isotopic signature of plant tissue, in both temporal and spatial scales. At the plot-scale where soil conditions are similar, there is little to no variation in foliar isotope values, but at the field-scale there appears to be a large amount of variability related to soil moisture and N loss. However, that variability is reduced when soil moisture values are grouped. There exists a significant difference between crop productivity and soil moisture, as the medium moisture range (%VWC 30-40) produced corn yields almost 10% greater than wet (%VWC \u3e40) and dry (%VWC The simulated crop growing experiment provided a simplified and controlled system for investigating the relationship between soil and plants. As the soil from all the barrels came from the same field location, and all N inputs were quantifiable, the differences in foliar δ15N provided meaningful insight into N-cycling. The combination of enriched foliar δ15N and soil N20 production in the relatively wet barrels provides reasonable conclusions about the value of using plant isotopes in the investigation of soil processes. This investigation is critical in furthering the efficiency of N application on crops; as well as, the subsequent decrease in the ecological impacts of farming. Reducing agricultural N leaching to ground and surface water requires a better understanding of N fate in the soil zone, and will result in more effective agricultural nutrient management

    Nursing Clinical Instructor Experiences of Empowerment in Rwanda: Applying Kanter\u27s and Spreitzer\u27s Theories

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    Clinical instructors (CIs) play a vital role in students’ development by facilitating learning in various health care practice environments. Quality nursing education hinges on the CI’s ability to enact his or her professional role. The purpose of this study was to explore Rwandan nursing clinical instructors’ experiences of structural and psychological empowerment. A descriptive qualitative method was used to obtain an understanding of CIs empowerment experiences in practice settings. Kanter’s (1993) Theory of Structural Power in Organizations and Spreitzer’s (1995) Psychological Empowerment Theory were used as a conceptual framework to interpret their experiences. Interview data from 21 nursing CIs in Rwanda were used to complete a secondary data analysis for this study. Most study participants perceived the structural components of informal power, resources, and support while formal power and opportunity were limited, diminishing their sense of structural empowerment. Psychological empowerment for the CIs in Rwanda stemmed from a sense of competence, meaning, impact and self-determination they had for their teaching roles and responsibilities in the practice setting. Implications and recommendations for CIs and administration are suggested to support, recruit and retain clinical instructors

    Mobile Devices and Apps as Accelerators for OER

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    At first sight, open educational resources (OER) and mobile devices would not seem to have much to do with one another. Mobile devices are rapidly replacing normal computers where creating and studying educational resources are concerned. That offers opportunities, but there are also downsides. These are explored in the present article

    An epidemiological appraisal of Berlin

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    Background Since the late 1950’s, a steadily increasing immigrant population in Germany is resulting in a subpopulation of aging immigrants. The German health care system needs to adjust its services—linguistically, culturally, and medically–for this subpopulation of patients. Immigrants make up over 20% of the population in Germany, yet the majority receive inadequate medical care. As many of the labor immigrants of the 1960s and 1970s are in need of hospice and palliative care (HPC), little is known about this specialized care for immigrants. This epidemiological study presents utilization of HPC facilities in Berlin with a focus on different immigrant groups. Methods A validated questionnaire was used to collect data from patients at 34 HPC institutions in Berlin over 20 months. All newly admitted patients were recruited. Anonymized data were coded and analyzed by using SPSS and compared with the population statistics of Berlin. Results 4118 questionnaires were completed and included in the analysis. At 11.4% the proportion of immigrants accessing HPC was significantly (p<0,001) below their proportion in the general Berlin population. This difference was especially seen in the age groups of 51–60 (21.46% immigrants in Berlin population, 17.7% immigrants in HPC population) and 61–70 years (16,9% vs. 13,1%). The largest ethnic groups are Turks, Russians, and Poles, with a different weighting than in the general population: Turkish immigrants were 24% of all Berlin immigrants, but only 13.6% of the study immigrant population (OR: 0.23, 95%CI: 0.18–0.29, p<0.001). Russian and Polish immigrants account for 5.6% and 9.2% in the population, but 11.5% and 24.8% in the study population respectively (Russian: OR 0.88, 95%CI: 0.66–1.16; Polish: OR 1.17, 95%CI: 0.97–1.42). Palliative care wards (PC) were used most often (16.7% immigrants of all PC patients); outpatient hospice services were used least often by immigrants (11.4%). Median age at first admission to HPC was younger in immigrants than non-immigrants: 61–70 vs. 71–80, p = 0.03. Conclusions Immigrants are underrepresented in Berlin´s HPC and immigrants on average make use of care at a younger age than non- immigrants. In this regard, Turkish immigrants in particular have the poorest utilization of HPC. These results should prompt research on Turkish immigrants, regarding access barriers, since they represent the largest immigrant group. This may be due to a lack of cultural sensitivity of the care-providers and a lack of knowledge about HPC among immigrants. In the comparison of the kinds of institutions, immigrants are less likely to access outpatient hospice services compared to PC. Apparently, PC appear to be a smaller hurdle for utilization. These results show a non-existent, but oft- cited “healthy immigrant effect” of the first generation of work immigrants, now entering old age. These findings correspond with studies suggesting increased health concerns in immigrants. Focused research is needed to promote efforts in providing adequate and fair access to HPC for all people in Berlin

    Nitrous Oxide Production in the Grand River, Ontario, Canada: New Insights from Stable Isotope Analysis of Dissolved Nitrous Oxide

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    Nitrous oxide (N₂O) is a powerful greenhouse gas, and its atmospheric concentration is increasing dramatically. N₂O is produced through the microbially-mediated processes of nitrification and denitrification. Since these processes have different substrates and isotopic enrichment factors, stable isotope analysis (δ¹⁵N and δ¹⁸O) of N₂O can be used to study the production of this important greenhouse gas. Although production in rivers accounts for a significant portion of the global N₂O budget, the isotopic composition of N₂O from this source is poorly characterized. Most of the previous work using stable isotopes of N₂O has been conducted in terrestrial or oceanic environments, and only one published study has measured δ¹⁵N and δ¹⁸O of N₂O produced in a riverine environment. The purpose of this research project was to use stable isotope analysis to characterize the processes responsible for N₂O production in the Grand River, Ontario, Canada, and to determine the spatial and temporal variability of the isotopic composition of the N₂O flux. To meet the study objectives, an offline “purge and trap” method was developed to collect and purify dissolved N₂O for stable isotope analysis. Using this method, δ¹⁵N and δ¹⁸O analysis of dissolved N₂O is possible for samples with concentrations as low as 6 nmol N₂O/L. Due to the isotopic effects of gas exchange and the back flux of tropospheric N₂O, there is a complex relationship between the δ¹⁵N and the δ¹⁸O of source, dissolved, and emitted N₂O in aquatic environments. A simple box model (SIDNO – Stable Isotopes of Dissolved Nitrous Oxide) was developed to properly interpret isotopic data for dissolved N₂O. Using this model, it was determined that the isotopic composition of emitted N₂O is much more representative of N₂O production in aquatic environments than the isotopic composition of dissolved N₂O. If the concentration, δ¹⁵N and δ¹⁸O of dissolved N₂O are measured, the magnitude and isotopic composition of the N₂O flux can be calculated. Sampling downstream of the major wastewater treatment plants (WWTPs) on the Grand River indicates that nitrification and denitrification in the river are strongly tied to diel changes in dissolved oxygen (DO) concentration. During the day, when DO concentrations are high, nitrification or nitrifier-denitrification is the dominant N₂O production pathway, with sediment denitrification also contributing to N₂O production. At night, when DO concentrations are low, denitrification in the sediments and at the sediment / water interface is the dominant production pathway. Using the SIDNO model, N₂O produced during the day was found to have a δ¹⁵N of -22‰ and a δ¹⁸O of 43‰. N₂O produced at night had a δ¹⁵N of -30‰ and a δ¹⁸O of 30‰. The isotopic composition of N₂O emitted from the Grand River is dominated by night-time production downstream of the Waterloo and Kitchener WWTPs during the summer. The flux and time weighted annual average isotopic composition of N₂O emitted from the Grand River is -18.5‰ and 32.7‰ for δ¹⁵N and δ¹⁸O respectively. These values are significantly more depleted than the only other published data for riverine N₂O production. If the Grand River is representative of global riverine N₂O production, these results will have significant implications for the global isotopic budget for atmospheric N₂O

    Mobile devices and apps as accelerators of Open Educational Resources

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    The impact of preprinted prescription forms on medication prescribing errors in an ophthalmology clinic in northeast Thailand: a non-randomised interventional study

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    Objectives: To understand the incidence and types of medication prescribing errors in a low resource setting ophthalmology clinic and to determine the impact of a preprinted prescription based on the hospital formulary (FormularyScript) on medication prescribing errors. Design: Non-randomised interventional study. Setting: Ophthalmology clinic in a teaching hospital in northeast Thailand. Participants: 4349 handwritten prescriptions collected from October 2009 to December 2009, and 4146 FormularyScripts collected from February 2010 to May 2010. Primary and Secondary Outcome Measures: All prescriptions from the handwritten and FormularyScript groups were analysed for medication error rates by types (legibility, ambiguous, incomplete, abbreviation and accuracy) and subtypes (drug name, strength, which eye, route and dispensed amount). Results: Comparison of error rates in the two groups showed a 10-fold reduction in the overall error rate using FormularyScript (32.9%–3.5%, p<0.001). FormularyScripts were associated with statistically significant (p<0.001) decreases in the following error types: legibility (16.1%–0.1%), incomplete (16.1%–0.1%) and abbreviation (3.1%–0.3%). There was no statistically significant change in accuracy errors (0.8%–0.6%, p=0.21). Ambiguous errors increased with FormularyScripts (0.6%–2.5%, p<0.001), likely due to the introduction of new ways to make errors. Decreases were seen in all legibility, abbreviation and accuracy error subtypes, and four out of six incomplete error subtypes. There were statistically significant increases in both ambiguous error subtypes: which eye (0.3%–2.5%, p<0.001) and drug name (0.3%–0.6%, p=0.03). Conclusions: In our study population, outpatient medication prescribing errors were common and primarily due to legibility and incomplete error types. A preprinted prescription form has the potential to decrease medication prescribing errors related to legibility, incomplete prescribing information and use of unacceptable abbreviations without changing the overall rate of accuracy errors. However, new error types can occur
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