African Children’s Songs: A Legendary Teaching Tool

This paper presents a multicultural perspective of the historical and legendary analysis of African American children’s songs highlighting the important interpersonal familial relationships that have been noted teaching tools for African American children. The data includes multiple songs that have been used for generations to teach children values, history and cultural experiences with life enhancing strength and determination.These diverse experiences are characterized by historical practices that called for African American families to find multimodal means of teaching their children when it was against the law for African Americans to learn to read or to become educated.This research reveals that at various stages in the lives of African American children, parents and extended family members found ways to culturally educate their children. This was done through use of historical and generational African American songs and games. They have been instrumental in providing hope of a better life for those who were oppressed and often denied some of life’s inalienable rights.Teachers at all grade levels including ESL and Special Education could enhance children’s learning through use of multimodal thinking and learning activities

The safe insertion of peripheral intravenous catheters : a mixed methods descriptive study of the availability of the equipment needed

Background: Intravenous cannulation is undertaken in a high proportion of hospitalised patients. Much international attention has been given to the use of care bundles to reduce the incidence of infection in these patients. However, less attention has been given to the systems required to ensure availability of the equipment needed to support these care bundles. Our objectives were to assess how reliably the equipment recommended for a peripheral intravenous care bundle was available for use, and to explore factors which contributed to its non-availability. Methods: We studied 350 peripheral cannula insertions in three NHS hospital organisations across the UK. Staff inserting cannulae were asked to report details of all equipment problems. Key staff were then interviewed to identify the causes of problems with equipment availability, using semi-structured qualitative interviews and a standard coding frame. Results: 47 equipment problems were recorded during 46 of 350 cannulations, corresponding to a reliability of 87%, or 94% if problems with sharps disposal were excluded. Overall reliability was similar in all three organisations, but the types of problem varied. Interviews revealed a variety of causes including issues associated with purchasing policies, storage facilities, and lack of teamwork and communication in relation to reordering. The many human factors related to the supply chain were highlighted. Often staff had adopted work-arounds to deal with these problems. Conclusions: Overall, 87% of cannulations had the correct and functional equipment available. Different problems were identified in different organisations, suggesting that each had resolved some issues. Supply chain management principles may be useful to support best practice in care bundle delivery. Keywords: Cannulation, Patient safety, Equipment, Care bundles, Hospital acquired bacteraemia, Systems reliabilit

Review of fly-ash as a supplementary cementitious material

This paper presents a review of fly-ash as a Supplementary Cementitious Material (SCM) in concrete in terms of its effects on hydration and durability. The climate change agenda has focused the cement and concrete industry on using low embodied CO2 materials and much effort has been made on incorporating industrial by-products into cement as SCMs. With worldwide cement production (circa 4 billion tonnes) currently accounting for approximately 8% of global CO2 emissions and 7% of industry energy use, the use of suitable SCMs to partially replace cement in concrete is extremely important. However, while coal-fired power stations are in the decline, due to the need for more sustainable energy generation, there remains stockpiles of fly-ash for potential use as an SCM. This creates opportunities for ashes not previously used in concrete to be studied both in terms of its behaviour during hydration and durability performance in harsh environments. However, these new fly-ash sources need to be studied carefully due to uncertainties about their physical and chemical constituents, reactivity, long term stability and phase relationships and minor elements distribution due to the variability in the source of coal. The work presented includes a review of fly-ash in terms of its effects during cement hydration and contribution to concretes performance in harsh environments from the literature

Thermodynamic Modelling of Harsh Environments on the Solid Phase Assemblage of Hydrating Cements Using PHREEQC

Poor durability of reinforced concrete structures can lead to serious structural failures. An accurate model to observe the effects of aggressive agents like carbonation, sulfate ingress, and seawater solutions on the solid phase assemblagewill help designers and specifiers better understand howcement behaves in these environments. This paper presents the first steps in developing such a model using the PHREEQC geochemical software by accounting for alkali binding and dissolution. It also presents the use of discrete solid phases (DSPs) to account for the solid-solution behaviour of siliceous hydrogarnet and magnesium silicate hydrate (M-S-H). A new thermodynamic description of the vaterite phase has also been developed for this work using the cemdata18 thermodynamic database. The predicted phase assemblages of cements in these environments here agree with previously published findings using a different thermodynamic model supported with experimental data

Modelling the hydrating behaviour of fly-ash in blended cements using thermodynamics

This paper presents a new method to thermodynamically model the hydration behaviour of fly-ash (FA) blended cements by deriving individual phase descriptions depending on the proportion of FA in the blended cement. The predicted hydrated phase assemblage, pore solution chemistries and pH over 1,000 days of hydration and with increasing FA proportions are presented. The thermodynamic data for the FA phases are derived using oxide proportions and mineral compositions are copied directly into the PHREEQC input file. The FA phases take account of all minerals to give a more accurate description of its behaviour during hydration. The calcium aluminosilicate hydrate (C-A-S-H) gel model consists of several Discrete Solid Phases (DSPs) derived from the quinary solid solution end-members in the cemdata18 database [1]. This method has been used previously by the authors to give reliable and computationally efficient results when modelling OPC hydration and extended here for C-A-S-H, accounting for its strongly incongruent dissolution. A number of blended cements with FA contents ranging from 0-35% (in 5% steps) were simulated. As the amount of FA in the blended cement increases, the results show a destabilization of calcium hydroxide at higher replacement levels, more hydrotalcite than OPC, the formation of strätlingite and AFm & AFt phases like monosulfate/monocarbonate and ettringite respectively. The dissolution of Portland cement is modelled using a well-known empirical approach. FA dissolution is modelled using an approach taken from the literature that gave good correlations with experimental data

Circadian Rhythms in Patients with ST-Elevation Myocardial Infarction

BACKGROUND: Circadian rhythms with regard to time of symptom onset for patients with acute myocardial infarction have been observed, although their relationship to outcomes has been debated. We evaluated these rhythms in patients with ST-elevation myocardial infarction as a function of the 24-hour circadian cycle. METHODS AND RESULTS: The relationship between onset of symptoms during the 24-hour circadian cycle and prehospital delays from symptom onset to hospital arrival, timeliness of reperfusion, and in-hospital death was assessed in 2143 patients with ST-elevation myocardial infarction presenting from 2004-2008 at 1 of 3 tertiary-care healthcare ST-elevation myocardial infarction systems. There was a significant association between time of onset and the circadian cycle, with the greatest percentage (39%) of patients experiencing onset between 8 AM and 3 PM (P\u3c0.001). Time of onset was associated with prehospital delay and timeliness of reperfusion. Patients with onset from 12 AM to 5:59 AM had median prehospital delays of 121 minutes versus 70 minutes from 12 PM to 5:59 PM (P\u3c0.001). Patients with onset time from 12 AM to 5:59 AM had median door-to-balloon times of 75 minutes versus 60 minutes from 6 AM to 11:59 AM (P\u3c0.001). Using multivariable modeling to control for baseline patient characteristics, prehospital delay, and timeliness of reperfusion, there was no significant association between time of symptom onset with in-hospital death. CONCLUSIONS: Patients with ST-elevation myocardial infarction exhibit significant circadian patterns in symptom onset, prehospital delay, and timeliness of reperfusion. Patients who develop symptoms from 12 AM to 5:59 AM present with longer prehospital delays and have longer door-to-balloon times. After multivariable adjustment, there was no significant association between circadian patterns of time of onset and in-hospital death

Deriving discrete solid phases from CSH-3T and CSHQ end-members to model cement hydration in PHREEQC

This paper presents a cement hydration model over time using the CEMDATA thermodynamic database and a series of discrete solid phases (DSP) to represent calcium silicate hydrate (C-S-H) as a ternary (CSH-3T) and quaternary (CSHQ) solid solution. C-S-H in cement is amorphous and poorly crystalline with a range of molar Ca/Si ratios = 0.6-1.7 and displays strongly incongruent dissolution behaviour where the release of calcium into solution is several orders of magnitude greater than silicon. It is therefore important that any cement hydration model provides a credible account of this behaviour. C-S-H has been described in the CEMDATA thermodynamic database as a number of binary, ternary and quaternary solid solutions using different end-members with differing levels of complexity. While solid solutions can be included in most modern geochemical software programs, it often leads to a significant increase in computation time. This paper presents how the two of the more complex C-S-H solid solutions, CSH-3T and CSHQ, available in the CEMDATA database, can be represented by DSP to model cement hydration over time using the PHREEQC geochemical software. By using DSP in place of solid solutions, analysis time is much improved with no loss in accuracy in producing stable phase assemblages and reasonable predictions of pH over time

Using Photovoltaics to Power Electrochemical Chloride Extraction from Concrete

Corrosion of embedded steel in reinforced concrete (RC) is a world-wide problem, that reduces structural performance and lifespan. Chloride attack may be a result of seawater, de-icing salts or contaminated admixtures, brought on by ingress of chlorides into the concrete. Electrochemical Chloride Extraction (ECE) is a non-destructive treatment for contaminated RC structures, that due to uncertainty of treatment times and applied current densities, is only 50% effective. It is often diesel powered has an environmental impact and often very costly due to the long treatment times. To improve the efficiency of ECE the influences of concrete resistance, cement type and duration of treatment have been investigated in an experimental programme. The use of Photovoltaic (PV) panels to improve the efficiency of ECE is presented which replace fossil fuels as a power source enabling a more environmentally sustainable treatment. These findings will increase the life span of vital infrastructure and reduce expensive ongoing repairs with decreased traffic congestion and inconveniences associated with bridge repairs

Experimental determination of the temperature dependence of oxygen-isotope fractionation between water and chitinous head capsules of chironomid larvae

Oxygen-isotope values of invertebrate cuticle preserved in lake sediments have been used in palaeoenvironmental reconstructions, generally with the assumption that fractionation of oxygen isotopes between cuticle and water (\upalpha_{\text{cuticle}-\text{H}_{2}\text{O}}) is independent of temperature. We cultured chironomid larvae in the laboratory with labelled oxygen-isotope water and across a range of closely controlled temperatures from 5 to 25 °C in order to test the hypothesis that fractionation of oxygen isotopes between chironomid head capsules and water (\upalpha_{\text{chironomid}-\text{H}_{2}\text{O}}) is independent of temperature. Results indicate that the hypothesis can be rejected, and that \upalpha_{\text{chironomid}-\text{H}_{2}\text{O}} decreases with increasing temperature. The scatter in the data suggests that further experiments are needed to verify the relationship. However, these results indicate that temperature-dependence of \upalpha_{\text{chironomid}-\text{H}_{2}\text{O}} should be considered when chironomid δ18O is used as a paleoenvironmental proxy, especially in cases where data from chironomids are combined with oxygen-isotope values from other materials for which fractionation is temperature dependent, such as calcite, in order to derive reconstructions of past water temperature

Magnetotransport in p-type Ge quantum well narrow wire arrays

We report magnetotransport measurements of a SiGe heterostructure containing a 20 nm p-Ge quantum well with a mobility of 800 000 cm2 V−1 s−1. By dry etching arrays of wires with widths between 1.0 μm and 3.0 μm, we were able to measure the lateral depletion thickness, built-in potential, and the phase coherence length of the quantum well. Fourier analysis does not show any Rashba related spin-splitting despite clearly defined Shubnikov-de Haas oscillations being observed up to a filling factor of ν = 22. Exchange-enhanced spin-splitting is observed for filling factors below ν = 9. An analysis of boundary scattering effects indicates lateral depletion of the hole gas by 0.5 ± 0.1 μm from the etched germanium surface. The built-in potential is found to be 0.25 ± 0.04 V, presenting an energy barrier for lateral transport greater than the hole confinement energy. A large phase coherence length of 3.5 ± 0.5 μm is obtained in these wires at 1.7 K.This work was supported by the EPSRC funded “Spintronic device physics in Si/Ge heterostructures” EP/J003263/1 and EP/J003638/1 projects and a Platform Grant No. EP/J001074/1.This is the author accepted manuscript. The final version is available from AIP via http://dx.doi.org/10.1063/1.4919053