136 research outputs found

    Online college laboratory courses: Can they be done and will they affect graduation and retention rates?

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    Online education has been steadily growing during the last decade. This growth has mainly taken place in the non-laboratory science fields. This essay describes some of the best practices to increase and maintain student retention, increase student engagement and increase graduation rates for college running online laboratory science courses. This article further discusses how to run successful, hands-on laboratory courses for your online students. The most common issues are being discussed and what can be done to provide the students with the same hands-on experience online as what they would experience in a more traditional classroom setting.DOI: 10.18870/hlrc.v5i4.28

    Wall Lake, South Dakota : A Case Study in Geographic Planning

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    Wall Lake is a hypereutrophic (overenriched with nutrients) glacial lake similar in character to many other glacial lakes in South Dakota. As is the case with most glacial lakes, Wall Lake is naturally eutrophic (nutrient enriched) because of the nutrient rich loess which usually occurs in close proximity to glacial kettles and is mixed with nutrient rich glacial till. A hypereutrophic state occurs when additional nutrients are added to the lake by such sources as agricultural runoff, mixing of water with enriched sediments, and by wastewater systems. The result is the accelerated natural progression from lake, to wetland, to dry land. Overenrichment and contamination of the lake cause the overabundant growth of algae, fish kill due to oxygen depletion, unsafe bacterial conditions for water immersion recreation, and the aesthetically displeasing odor of hydrogen sulfide which smells like rotten eggs. Wall Lake is experiencing hypereutrophication which limits the recreational use by residents of Minnehaha County. Agricultural practices and wastewater systems influx has accelerated the natural processes of the lake so that it is feared that it may become a swamp prematurely. The purpose of this study is to determine the feasibility of restoring the lake for Minnehaha County residents. Initially, current, consistent data analysis of runoff from the watershed area of Wall Lake was to be included. Drought prevented watershed runoff from being sampled for the majority of the testing period. Water samples disclosed that bacterial contamination and high nutrient levels continued to occur. This paper suggests that the most probable source of bacterial contamination during this period of testing was wastewater systems

    Dynamics of propagation patterns and anti-arrhythmic mechanisms during atrial fibrillation

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    Atrial fibrillation leads to a rapid and irregular heartbeat. It is an extremely dynamic process involving many electrical waves. Wave patterns can be identified to help direct catheter treatments for atrial fibrillation. An accurate interpretation requires the use of many electrodes and a sufficiently long hospital admission. Vernakalant is the most recent medicine used to treat atrial fibrillation. While Vernakalant proved to be highly effective in treating this arrhythmia, we found the action mechanism to be different than previously thought. Vernakalant slows down electrical activation, which is associated with life-threatening arrhythmias. Careful patient selection is therefore imperative

    Time course and mechanisms of endo-epicardial electrical dissociation during atrial fibrillation in the goat

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    Aims This study aims to determine the degree and mechanisms of endo-epicardial dissociation of electrical activity during atrial fibrillation (AF) and endo-epicardial differences in atrial electrophysiology at different stages of atrial remodelling. Methods and results Simultaneous high-density endo-epicardial mapping of AF was performed on left atrial free walls of goats with acute AF, after 3 weeks, and after 6 months of AF (all n = 7). Endo-epicardial activation time differences and differences in the direction of conduction vectors were calculated, endocardial and epicardial effective refractory periods (ERP) were determined, and fractionation of electrograms was quantified. Histograms of endo-epicardial activation time differences and differences in the direction of conduction vectors revealed two distinct populations, i.e. dissociated and non-dissociated activity. Dyssynchronous activity (dissociated in time) increased from 17 ± 7% during acute AF to 39 ± 17% after 3 weeks, and 68 ± 13% after 6 months of AF. Dissociation was more pronounced in thicker parts of the atrial wall (thick: 49.3 ± 21.4%, thin: 42.2 ± 19.0%, P < 0.05). At baseline, endocardial ERPs were longer when compared with epicardial ERPs (ΔERP, 21.8 ± 18 ms; P < 0.001). This difference was absent after 6 months of AF. The percentage of fractionated electrograms during rapid pacing increased from 9.4 ± 1.9% (baseline) to 18.6 ± 0.6% (6 months). Conclusion During AF, pronounced dissociation of electrical activity occurs between the epicardial layer and the endocardial bundle network. The increase in dissociation is due to owing to progressive uncoupling between the epicardial layer and the endocardial bundles and correlates with increasing stability and complexity of the AF substrat

    Stationary and Recurrent Properties of Atrial Fibrillation Conduction Patterns in Goat

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    Introduction. Electrical mapping of the atria is used to assess the substrate of atrial fibrillation (AF). Targeted ablation of the AF substrate assumes spatiotemporal stationarity. In this study we analyzed long AF recordings of AF using high-density contact mapping.Methods. In 12 goats with stable AF 10 successive 60s files were recorded, within a single AF episode. AF cycle length, fractionation index (FI), lateral dissociation, conduction velocity, breakthroughs and preferentiality of conduction (Prefi were assessed to construct AF-property maps. The Pearson correlation coefficient (PCC) between AF-property maps of consecutive recordings was calculated. Recurrence plots and recurrence quantification analysis were used to identify recurrent patterns.Results Spatiotemporal stationarity for the 6 properties were high, PCC ranged from 0.66 +/- 0.11 for Pref to 0.98 +/- 0.01 for FI. The PCC is not affected by the time delay between files. Yet, highly dynamic patterns were found. Recurrence plots revealed few (1.6 +/- 0.7) recurrent patterns in individual animals.Conclusions AF properties were stationary in stable AF. This cannot be attributed to stable recurrent conduction patterns. during This suggests that spatial properties of the atrium determine AF properties

    Incidence, prevalence, and trajectories of repetitive conduction patterns in human atrial fibrillation

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    AIMS: Repetitive conduction patterns in atrial fibrillation (AF) may reflect anatomical structures harbouring preferential conduction paths and indicate the presence of stationary sources for AF. Recently, we demonstrated a novel technique to detect repetitive patterns in high-density contact mapping of AF. As a first step towards repetitive pattern mapping to guide AF ablation, we determined the incidence, prevalence, and trajectories of repetitive conduction patterns in epicardial contact mapping of paroxysmal and persistent AF patients. METHODS AND RESULTS: A 256-channel mapping array was used to record epicardial left and right AF electrograms in persistent AF (persAF, n = 9) and paroxysmal AF (pAF, n = 11) patients. Intervals containing repetitive conduction patterns were detected using recurrence plots. Activation movies, preferential conduction direction, and average activation sequence were used to characterize and classify conduction patterns. Repetitive patterns were identified in 33/40 recordings. Repetitive patterns were more prevalent in pAF compared with persAF [pAF: median 59%, inter-quartile range (41-72) vs. persAF: 39% (0-51), P < 0.01], larger [pAF: = 1.54 (1.15-1.96) vs. persAF: 1.16 (0.74-1.56) cm2, P < 0.001), and more stable [normalized preferentiality (0-1) pAF: 0.38 (0.25-0.50) vs. persAF: 0.23 (0-0.33), P < 0.01]. Most repetitive patterns were peripheral waves (87%), often with conduction block (69%), while breakthroughs (9%) and re-entries (2%) occurred less frequently. CONCLUSION: High-density epicardial contact mapping in AF patients reveals frequent repetitive conduction patterns. In persistent AF patients, repetitive patterns were less frequent, smaller, and more variable than in paroxysmal AF patients. Future research should elucidate whether these patterns can help in finding AF ablation targets

    Methoderapport om Industriële emissies naar lucht te berekenen (actualisatie 2016) zoals gebruikt door de Emissieregistratie

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    In this technical report RIVM describes the updated methods that The Netherlands Pollutant Release and Transfer Register uses to calculate the emissions of contaminated substances into the air from the Industry, Energy Generating and Waste Processing sectors. Due to international treaties, such as the Kyoto protocol, the EU Emissions Ceiling (NEC Directive) and the Convention on Long-range Transboundary Air Pollution (CLRTAP), the Netherlands is obliged to always report in accordance with the most recent scientific insights regarding the emission of greenhouse gases, acidifying pollutants and substances related to large-scale air pollution. This description is used to substantiate the reported emissions. This report is targeted at the national and international reviewers that validate Dutch reports to the EU and UN.Het RIVM beschrijft in deze technische rapportage de geactualiseerde methoden waarmee de Nederlandse Emissieregistratie de uitstoot van verontreinigende stoffen naar de lucht berekent vanuit de sectoren Industrie, Energieopwekking en Afvalverwerking. Nederland is vanwege internationale verdragen, zoals het Kyoto-protocol, de EU-Emissieplafonds (NEC-Directive) en de Convention on Long-range Transboundary Air Pollution (CLRTAP), verplicht om steeds volgens de meest actuele wetenschappelijk inzichten te rapporteren over de uitstoot van broeikasgassen, verzurende stoffen en stoffen die gerelateerd zijn aan grootschalige luchtverontreiniging. Met deze beschrijving wordt de gerapporteerde uitstoot onderbouwd. Doelgroep voor deze rapportage zijn de (internationale) reviewers die de Nederlandse rapportages aan de EU en VN valideren.Ministerie van I&

    Physical and Pharmacological Restraints in Hospital Care:Protocol for a Systematic Review

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    Background: Physical and pharmacological restraints, defined as all measures limiting a person in his or her freedom, are extensively used to handle unsafe or problematic behavior in hospital care. There are increasing concerns as to the extent with which these restraints are being used in hospitals, and whether their benefits outweigh their potential harm. There is currently no comprehensive literature overview on the beneficial and/or adverse effects of the use of physical and pharmacological restraints in the hospital setting. Methods: A systematic review of the existing literature will be performed on the beneficial and/or adverse effects of physical and pharmacological restraints in the hospital setting. Relevant databases will be systematically searched. A dedicated search strategy was composed. A visualization of similarities (VOS) analysis was used to further specify the search. Observational studies, and if available, randomized controlled trials reporting on beneficial and/or adverse effects of physical and/or pharmacological restraints in the general hospital setting will be included. Data from included articles will be extracted and analyzed. If the data is suitable for quantitative analysis, meta-analysis will be applied. Discussion: This review will provide data on the beneficial and/or adverse effects of the use of physical and pharmacological restraints in hospital care. With this review we aim to guide health professionals by providing a critique of the available evidence regarding their choice to either apply or withhold from using restraints. A limitation of the current review will be that we will not specifically address ethical aspects of restraint use. Nevertheless, the outcomes of our systematic review can be used in the composition of a multidisciplinary guideline. Furthermore, our systematic review might determine knowledge gaps in the evidence, and recommendations on how to target these gaps with future research. Systematic Review Registration: PROSPERO registration number: CRD42019116186
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