426 research outputs found
Plant Isotopes as Indicators of N Cycling Processes in Agricultural Fields
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
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
Clinical instructors (CIs) play a vital role in studentsâ development by facilitating learning in various health care practice environments. Quality nursing education hinges on the CIâs ability to enact his or her professional role. The purpose of this study was to explore Rwandan nursing clinical instructorsâ experiences of structural and psychological empowerment.
A descriptive qualitative method was used to obtain an understanding of CIs empowerment experiences in practice settings. Kanterâs (1993) Theory of Structural Power in Organizations and Spreitzerâs (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
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
Background Since the late 1950âs, a steadily increasing immigrant population
in Germany is resulting in a subpopulation of aging immigrants. The German
health care system needs to adjust its servicesâlinguistically, culturally,
and medicallyâfor 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 51â60 (21.46% immigrants in Berlin population, 17.7% immigrants in
HPC population) and 61â70 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: 0.18â0.29, 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:
0.66â1.16; Polish: OR 1.17, 95%CI: 0.97â1.42). 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: 61â70 vs.
71â80, 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 âhealthy immigrant effectâ 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
Nitrous oxide (NâO) is a powerful greenhouse gas, and its atmospheric concentration is increasing dramatically. NâO is produced through the microbially-mediated processes of nitrification and denitrification. Since these processes have different substrates and isotopic enrichment factors, stable isotope analysis (δšâľN and δšâ¸O) of NâO can be used to study the production of this important greenhouse gas.
Although production in rivers accounts for a significant portion of the global NâO budget, the isotopic composition of NâO from this source is poorly characterized. Most of the previous work using stable isotopes of NâO has been conducted in terrestrial or oceanic environments, and only one published study has measured δšâľN and δšâ¸O of NâO produced in a riverine environment. The purpose of this research project was to use stable isotope analysis to characterize the processes responsible for NâO production in the Grand River, Ontario, Canada, and to determine the spatial and temporal variability of the isotopic composition of the NâO flux.
To meet the study objectives, an offline âpurge and trapâ method was developed to collect and purify dissolved NâO for stable isotope analysis. Using this method, δšâľN and δšâ¸O analysis of dissolved NâO is possible for samples with concentrations as low as 6 nmol NâO/L.
Due to the isotopic effects of gas exchange and the back flux of tropospheric NâO, there is a complex relationship between the δšâľN and the δšâ¸O of source, dissolved, and emitted NâO in aquatic environments. A simple box model (SIDNO â Stable Isotopes of Dissolved Nitrous Oxide) was developed to properly interpret isotopic data for dissolved NâO. Using this model, it was determined that the isotopic composition of emitted NâO is much more representative of NâO production in aquatic environments than the isotopic composition of dissolved NâO. If the concentration, δšâľN and δšâ¸O of dissolved NâO are measured, the magnitude and isotopic composition of the NâO 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 NâO production pathway, with sediment denitrification also contributing to NâO 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, NâO produced during the day was found to have a δšâľN of -22â° and a δšâ¸O of 43â°. NâO produced at night had a δšâľN of -30â° and a δšâ¸O of 30â°. The isotopic composition of NâO 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 NâO emitted from the Grand River is -18.5â° and 32.7â° for δšâľN and δšâ¸O respectively. These values are significantly more depleted than the only other published data for riverine NâO production. If the Grand River is representative of global riverine NâO production, these results will have significant implications for the global isotopic budget for atmospheric NâO
The impact of preprinted prescription forms on medication prescribing errors in an ophthalmology clinic in northeast Thailand: a non-randomised interventional study
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%â3.5%, p<0.001). FormularyScripts were associated with statistically significant (p<0.001) decreases in the following error types: legibility (16.1%â0.1%), incomplete (16.1%â0.1%) and abbreviation (3.1%â0.3%). There was no statistically significant change in accuracy errors (0.8%â0.6%, p=0.21). Ambiguous errors increased with FormularyScripts (0.6%â2.5%, 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%â2.5%, p<0.001) and drug name (0.3%â0.6%, 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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