Students’ evaluation of a computerized patient simulator in nursing education and its effect on the results of preclinical te

The aim of the study was two-fold: to evaluate nursing students’ experiences of active participation in the use of a-computerized simulation manikin during preclinical first-year Bachelor’s studies, and to evaluate the effect of active participation in simulation by comparing active students’ result with observers’ result on preclinical test. An evaluative case study design was used to evaluate simulation with a computerized manikin as a pedagogical learning method. A questionnaire was used to evaluate the active students’ experiences. The second part was a comparison between the active students’ and the observers’ preclinical test results. Findings indicated that the students thought simulation was beneficial, feedback from peers and lecturer was helpful and reflection during debriefing was beneficial. A significant difference was seen between those students who actively participated and those who observed in relation to the pass/fail preclinical test. Nursing students experienced simulation with a computerized manikin as being a beneficial pedagogical learning method, and active participation in a simulation situation can help students pass their preclinical test

Étude de l'interaction Eau-Basaltes lors d'injection de CO2

Les dangers potentiels liés à l'augmentation de la teneur en CO2 de l'atmosphère, tels que les changements climatiques ou l'élévation du niveau des mers, ont provoqué un grand intérêt pour la séquestration du gaz carbonique dans les formations géologiques. Le moyen thermodynamiquement le plus sûr pour stocker le carbone est sous la forme de minéraux carbonatés, mais il exige une source de cations divalents qui ne soit pas carbonatée. Les roches basaltiques qui présentent de fortes teneurs en calcium, magnésium et fer peuvent être une de ces sources et la possibilité de former des minéraux carbonatés par injection de CO2 dans les roches basaltiques est en cours d'investigation en Islande et dans d'autres endroits du monde. Dans ce cadre, l'objectif de cette thèse est de contribuer à l'optimisation de la précipitation des carbonates dans les basaltes lors de l'injection de CO2 grâce à une série d'études de terrain et de laboratoire complémentaires. Une étude détaillée de la composition chimique des eaux souterraines au pied du volcan Mont Hekla, dans le sud de l'Islande, a d'abord été menée afin d'évaluer l'évolution chimique des fluides et la mobilité des métaux toxiques lors des interactions entre basalte et fluides riches en CO2. Ces fluides fournissent un analogue naturel pour estimer les conséquences de la séquestration du CO2 dans les basaltes. La teneur de ces fluides en carbone inorganique dissous diminue de 3,88 à 0,746 mmole/kg avec l'augmentation de la mise en solution du basalte tandis que le pH passe de 6,9 à 9,2. Ces observations fournissent une preuve directe du potentiel qu'offre la dissolution du basalte pour séquestrer le CO2. Les concentrations des métaux toxiques dans ces eaux sont faibles et la modélisation des chemins réactionnels suggère que la calcite et les (oxy)hydroxydes de fer piègent ces métaux, suite à l'alcalinisation des fluides induite par la dissolution continue du basalte. On sait que ce sont les cations divalents libérés par la dissolution du verre basaltique qui contrôlent la minéralisation du gaz carbonique dans les basaltes. La vitesse de dissolution du verre basaltique peut être accrue par l'addition de ligands qui se complexent avec Al3+. L'ion SO42- fait partie de ces ligands et l'étude de son impact sur la vitesse de dissolution du verre basaltique a été conduite dans des réacteurs de type 'mixed flow' à 50°C et 3 < pH < 10. Le soufre est souvent présent dans les gaz émis par les centrales électriques et son stockage constitue un challenge environnemental. La co-injection avec CO2, si elle est réalisable, peut donc constituer une nouvelle méthode peu couteuse de stockage du soufre généré par l'industrie. En accord avec les modèles actuels décrivant la cinétique de dissolution du verre basaltique en fonction de la composition de la solution aqueuse, les résultats de ce travail montrent que SO42-augmente la vitesse de dissolution du verre aux conditions acide mais qu'il n'a aucun effet aux pH alcalins. Ces résultats suggèrent à la fois que 1) la co-injection de sulfate peut accélérer la minéralisation du CO2 dans les basaltes et 2) les modèles cinétiques existant permettent une description précise de la dissolution du verre basaltique. Afin d'évaluer plus précisément l'impact des ions sulfates sur la vitesse de précipitation des carbonates, la vitesse de précipitation de la calcite en régime stationnaire a été mesurée dans des réacteurs à circulation 'mixed flow' à 25°C et pH ~ 9.1. Les résultats montrent qu'en présence de 0.005 M de Na2SO4 la vitesse de précipitation de la calcite est diminuée d'environ 40% et qu'ainsi la co-injection de sulfate peut ralentir la précipitation de la calcite aux pH typiques de la précipitation de ce minéral en subsurface. Des expériences supplémentaires sont prévues pour caractériser définitivement l'effet du sulfate aux conditions attendues aux sites d'injection du CO2 en subsurface.The potential dangers with increased concentration of CO2 in the atmosphere, such as climate changes and sea level rise, have lead to an interest in CO2 sequestration in geological formations. The thermodynamically most stable way to store carbon is as carbonate minerals. Carbonate mineral formation, however, requires divalent cations originating from a non-carbonate source. One such source is basaltic rocks which contain high concentrations of Ca2+, Mg2+ and Fe2+. The potential for forming carbonate minerals through the injection of CO2 into basalt is under investigation in Iceland and several other places around the world. The aim of this thesis is to help optimize carbonate mineral precipitation in basalts during CO2 injection through a series of related field and laboratory studies. A detailed study of the chemical composition of the groundwater surrounding the Mt. Hekla volcano in south Iceland was performed to assess fluid evolution and toxic metal mobility during CO2-rich fluid basalt interaction. These fluids provide a natural analogue for evaluating the consequences of CO2 sequestration in basalt. The concentration of dissolved inorganic carbon in these groundwaters decreases from 3.88 to 0.746 mmol/kg with increasing basalt dissolution while the pH increases from 6.9 to 9.2. This observation provides direct evidence of the potential for basalt dissolution to sequester CO2. The concentrations of toxic metals in these waters are low and reaction path modeling suggests that calcite and Fe(III) (oxy)hydroxides scavenge these metals as the fluid phase is neutralized by further basalt dissolution. The rate limiting step for mineralization of CO2 in basalt is thought to be the release of divalent cations to solution through basaltic glass dissolution. The dissolution rate of basaltic glass can be increased by adding ligands which complex aqueous Al3+. Aqueous SO42- can complex Al3+ and the effect of SO42- on the dissolution rate of basaltic glass was studied using mixed flow reactors at 3 < pH < 10 at 50 °C. Moreover, sulphur is often present in the flue gases of power plants and their disposal also poses an environmental challenge. If possible, co-injection of sulfur with CO2 could provide a novel cost effective disposal method for industrial generated sulphur. Consistent with current models describing basaltic glass dissolution by aqueous solution composition, results show that SO42- increases the dissolution rate of the glass in acidic conditions, while no effect was found in alkaline solutions. These results suggest both that 1) co-injection of sulfate may accelerate CO2 mineralization in basalts, and 2) existing kinetic models provide an accurate description of basaltic glass dissolution. To further assess the potential effect of SO42- on the precipitation rate of carbonates, steady-state rates of calcite precipitation were measured in mixed flow reactors at 25 °C and pH ~9.1. The results show that 0.005 M Na2SO4 decreases the precipitation rate of calcite by ~40%. This result suggests that co-injected sulphate could slow calcite precipitation in the subsurface at pH conditions typical of calcite precipitation. Further experiments are planned to completely define these effects at conditions expected at subsurface CO2 injection sites

Does regular antenatal exercise promote exclusive breastfeeding during the first 3 months of life? Secondary analyses of a randomized controlled trial

INTRODUCTION Exclusive breastfeeding (EBF) and antenatal exercise are independently ssociated with positive short- and long-term health effects for women and their children. The aims of the study were to investigate whether antenatal exercise promotes EBF three months postpartum and further to explore factors associated with EBF at three months postpartum. METHODS This study was a follow-up of a Norwegian two-center randomized controlled trial to assess the effect of an antenatal exercise protocol. The recruited pregnant women were randomized to either a 12-week standardized antenatal exercise program with one weekly group training led by a physiotherapist and two weekly home training sessions or standard antenatal care. Women reported breastfeeding status in a questionnaire at three months postpartum. RESULTS Of the 726 women, 88% were EBF at three months postpartum. There was no significant difference in EBF rates between the intervention group (87%) and the control group (89%). EBF was positively associated with maternal education (AOR=3.4; 95% CI: 1.7–6.7) and EBF at discharge from the hospital (AOR=22.2; 95% CI: 10–49). Admission to neonatal intensive care unit was identified as a significant barrier to EBF (AOR=0.2; 95% CI: 0.1–0.4). Significantly more women in the non-EBF group had sought professional help compared to women in the EBF group (p≤0.001). CONCLUSIONS Regular physical exercise during pregnancy did not influence the exclusive breastfeeding rates at three months postpartum. Considering the health effects of exclusive breastfeeding and antenatal physical exercise, studies with follow-up periods beyond three months postpartum are warranted.publishedVersio

On the buffer capacity of CO2-charged seawater used for carbonation and subsequent mineral sequestration

Successful mineral trapping of carbon dioxide faces the challenge of effectively titrating a CO2-charged acidic injection solution to pH conditions favorable to carbonate precipitation -using the rock as primary alkalinity source. To illustrate the magnitude of this task, buffer capacities of seawater solutions equilibrated with different partial pressure of CO2 are presented, under open and closed conditions. A number of mechanisms can be evoked to overcome the large buffer intensity of the injection fluid, including dilution, dissolution kinetic catalysis and increasing reaction temperature. Buffer capacity – pH plots are presented to aid in understanding how buffer capacity changes as a function of the presence and concentration of key solutes, like fluoride

Rapid solubility and mineral storage of CO2 in basalt

The long-term security of geologic carbon storage is critical to its success and public acceptance. Much of the security risk associated with geological carbon storage stems from its buoyancy. Gaseous and supercritical CO2 are less dense than formation waters, providing a driving force for it to escape back to the surface. This buoyancy can be eliminated by the dissolution of CO2 into water prior to, or during its injection into the subsurface. The dissolution makes it possible to inject into fractured rocks and further enhance mineral storage of CO2 especially if injected into silicate rocks rich in divalent metal cations such as basalts and ultra-mafic rocks. We have demonstrated the dissolution of CO2 into water during its injection into basalt leading to its geologic solubility storage in less than five minutes and potential geologic mineral storage within few years after injection [1–3]. The storage potential of CO2 within basaltic rocks is enormous. All the carbon released from burning of all fossil fuel on Earth, 5000 GtC, can theoretically be stored in basaltic rocks [4]

The effect of pH, grain size, and organic ligands on biotite weathering rates

Biotite dissolution rates were determined at 25 °C, at pH 2–6, and as a function of mineral composition, grain size, and aqueous organic ligand concentration. Rates were measured using both open- and closed-system reactors in fluids of constant ionic strength. Element release was non-stoichiometric and followed the general trend of Fe, Mg > Al > Si. Biotite surface area normalised dissolution rates (ri) in the acidic range, generated from Si release, are consistent with the empirical rate law: ri=kH,iaxiH+ where kH,i refers to an apparent rate constant, aH+ designates the activity of protons, and xi stands for a reaction order with respect to protons. Rate constants range from 2.15 × 10−10 to 30.6 × 10−10 (molesbiotite m−2 s−1) with reaction orders ranging from 0.31 to 0.58. At near-neutral pH in the closed-system experiments, the release of Al was stoichiometric compared to Si, but Fe was preferentially retained in the solid phase, possibly as a secondary phase. Biotite dissolution was highly spatially anisotropic with its edges being ∼120 times more reactive than its basal planes. Low organic ligand concentrations slightly enhanced biotite dissolution rates. These measured rates illuminate mineral–fluid–organism chemical interactions, which occur in the natural environment, and how organic exudates enhance nutrient mobilisation for microorganism acquisition

The chemistry and saturation states of subsurface fluids during the in situ mineralisation of CO2 and H2S at the CarbFix site in SW-Iceland

In situ carbonation of basaltic rocks could provide a long-term carbon storage solution, which is essential for the success and public acceptance of carbon storage. To demonstrate the viability of this carbon storage solution, 175 tonnes (t) of pure CO2 and 73 tonnes (t) of a 75% CO2-24% H2S-1% H2-gas mixture were sequentially injected into basaltic rocks at the CarbFix site at Hellisheidi, SW-Iceland from January to August 2012. This paper reports the chemistry and saturation states with respect to potential secondary minerals of sub-surface fluids sampled prior to, during, and after the injections. All gases were dissolved in water during their injection into permeable basalts located at 500–800 m depth with temperatures ranging from 20 to 50 °C. A pH decrease and dissolved inorganic carbon (DIC) increase was observed in the first monitoring well, HN-04, about two weeks after each injection began. At storage reservoir target depth, this diverted monitoring well is located ∼125 m downstream from the injection well. A significant increase in H2S concentration, however, was not observed after the second injection. Sampled fluids from the HN-04 well show a rapid increase in Ca, Mg, and Fe concentration during the injections with a gradual decline in the following months. Calculations indicate that the sampled fluids are saturated with respect to siderite about four weeks after the injections began, and these fluids attained calcite saturation about three months after each injection. Pyrite is supersaturated prior to and during the mixed gas injection and in the following months. In July 2013, the HN-04 fluid sampling pump broke down due to calcite precipitation, verifying the carbonation of the injected CO2. Mass balance calculations, based on the recovery of non-reactive tracers co-injected into the subsurface together with the acid-gases, confirm that more than 95% of the CO2 injected into the subsurface was mineralised within a year, and essentially all of the injected H2S was mineralised within four months of its injection. These results demonstrate the viability of the in situ mineralisation of these gases in basaltic rocks as a long-term and safe storage solution for CO2 and H2S

Tracking timescales of short-term precursors to large basaltic fissure eruptions through Fe–Mg diffusion in olivine

Petrological constraints on the timescales of pre-eruptive crystal storage and magma degassing provide an important framework for the interpretation of seismic, geodetic and gas monitoring data in volcanically active regions. We have used Fe–Mg diffusion chronometry in 86 olivine macrocrysts from the AD 1783–1784 Laki eruption on Iceland's Eastern Volcanic Zone to characterise timescales of crystal storage and transport in the lead-up to this eruption. The majority of these olivines have core compositions of Fo 81 olivines record Fe–Mg diffusion timescales of ∼124 days; these crystals are likely to have formed in mid-crustal magma chambers, been transferred to storage at shallower levels and then entrained into the Laki melt prior to eruption. Typical Fe–Mg diffusion timescales of 6–10 days are shorter than the average time interval between discrete episodes of the Laki eruption, indicating variable or pulsed disaggregation of stored crystals into the carrier liquid prior to the onset of each episode. The diffusion timescales coincide with historical accounts of strong and frequent earthquakes in southeast Iceland, which we interpret as being associated with mush disaggregation related to melt withdrawal and the initiation of dyke propagation from a crustal magma reservoir at ∼6 ± 3 km depth to the surface. We calculate pre-eruptive CO2 fluxes of 2–6 Mt d−1, assuming a pre-eruptive CO2 outgassing budget of 189.6 Mt for the Laki eruption and a constant rate of CO2 release in the 6–10 days preceding each eruptive episode. Our dataset indicates that petrological constraints on the timescales of magmatic processes occurring in the days leading up to historic eruptions may enhance our ability to forecast the onset of future large eruptions, both in Iceland and further afield

Weathering dynamics under contrasting Greenland Ice Sheet catchments

Chemical weathering dynamics in Greenland Ice Sheet (GrIS) catchments are largely unknown, due to a scarcity of field data. This paper presents the most comprehensive study to date of chemical weathering rates from four GrIS catchments of contrasting size. Cationic denudation rates varied greatly between catchments studied (2.6–37.6 tons km–2 a–1, world mean = 11.9 tons km–2 a–1), but were of the same order of magnitude to the world non-glacial riverine mean, and are greater than those documented in some major temperate rivers catchments (e.g., Mississippi (1.3 tons km–2 a–1) and Nile (0.4 tons km–2 a–1) rivers). These high chemical denudation rates indicate that the GrIS is a potential source of solute to downstream environments. Dissolved silica yields, indicative of silicate weathering rates, also varied by an order of magnitude, with upper values similar to the world mean (0.2–3.8 tons km–2 a–1, world mean = 3.53 tons km–2 a–1). Elevated chemical weathering rates in GrIS catchments are strongly influenced by the specific discharge, which drives flushing of the subglacial environment and physical erosion of the ice sheet bed. The direct relationship between specific discharge and chemical denudation rates supports the hypothesis that GrIS chemical weathering rates and solute fluxes are likely to increase with enhanced melt rates in a warming climate