Road traffic reduces pedestrian accessibility – Quantifying the size and distribution of barrier effects in an African city

BACKGROUND AND OBJECTIVE: Motorised traffic is growing rapidly in many African cities, creating barriers to the movement of pedestrians. This paper analyses the barrier effect of roads in Praia, the capital of Cabo Verde. We measured the barrier effect to potential trips to homes of other people and to food shops and analysed the distribution of the effect across areas and social groups. The paper contributes to the literature by: 1) quantifying the barrier effect of roads for the first time in an African city; 2) mapping the effect at the city level, and 3) developing indicators that account for land use (i.e. what is on the other side of the road). METHODS: We used spatial analysis to estimate, for each building in the city, two indicators: the proportions of the areas of other buildings and of food shops within 600m that are located across main roads. We then analysed the distribution of those indicators using descriptive statistics, cumulative frequencies, bivariate associations, and regression models. RESULTS: In some areas, roads are estimated to curtail more than 70% of the walking accessibility potential of residents. The effect is higher in older informal settlements than in formally planned areas or newer informal settlements, and it disproportionately affects individuals aged 65+. The effect is lower for households with very high and very low socio-economic status than for those with high, medium, or low status. The indicators are robust to changes in the assumptions (e.g. type of roads included, maximum walking distance, attractiveness of destinations) and provide extra information, compared with simpler indicators (e.g. distance to roads or length of roads within a certain distance)

Ca_{4}Sb_{2}O and Ca_{4}Bi_{2}O: two promising mixed-anion thermoelectrics

The environmental burden of fossil fuels and the rising impact of global warming have created an urgent need for sustainable clean energy sources. This has led to widespread interest in thermoelectric (TE) materials to recover part of the ∼60% of global energy currently wasted as heat as usable electricity. Oxides are particularly attractive as they are thermally stable, chemically inert, and formed of earth-abundant elements, but despite intensive efforts there have been no reports of oxide TEs matching the performance of flagship chalcogenide materials such as PbTe, Bi_{2}Te_{3} and SnSe. A number of ternary X_{4}Y_{2}Z mixed-anion systems, including oxides, have predicted band gaps in the useful range for several renewable-energy applications, including as TEs, and some also show the complex crystal structures indicative of low lattice thermal conductivity. In this study, we use ab initio calculations to investigate the TE performance of two structurally-similar mixed-anion oxypnictides, Ca_{4}Sb_{2}O and Ca_{4}Bi_{2}O. Electronic-structure and band-alignment calculations using hybrid density-functional theory (DFT), including spin–orbit coupling, suggest that both materials are likely to be p-type dopable with large charge-carrier mobilities. Lattice-dynamics calculations using third-order perturbation theory predict ultra-low lattice thermal conductivities of ∼0.8 and ∼0.5 W m^{−1} K^{−1} above 750 K. Nanostructuring to a crystal grain size of 20 nm is predicted to further reduce the room temperature thermal conductivity by around 40%. Finally, we use the electronic- and thermal-transport calculations to estimate the thermoelectric figure of merit ZT, and show that with p-type doping both oxides could potentially serve as promising earth-abundant oxide TEs for high-temperature applications

Perception of Nurses about Palliative Care: Experience from South-West Nigeria

Background: Nurses play a major role all over the world in the palliative care team.Aim: The aim of this study was to investigate the knowledge and attitude of nurses toward palliative care in a tertiary level hospital in Nigeria. Subjects and Methods: Setting: This cross-sectional questionnaire-based study was carried out among nurses at a tertiary health care facility inAdo-Ekiti, South-West Nigeria. Design: A cross-sectional questionnaire-based study was carried out. The questionnaire sought information about the sociodemographic profile of respondents, their knowledge of definition and philosophy of palliative care among other things. Descriptive statistics was used to obtain the general characteristics of the study participants, while Chi-square was used to determine the association between categorical variables. A two-sided P < 0.05 was considered as significant.Results: A total of 100 questionnaires were returned with a female preponderance among the respondents with F: M ratio of 9:1. Regarding the definition of palliative care, 71.8% (48/66) of the respondents  understood palliative care to be about pain medicine, 55% (33/60) thought it to be geriatric medicine, while 90.2% (83/92) felt palliative care is about the active care of the dying. Exactly 80.5% (66/82) respondents agreedthat palliative care recognizes dying as a normal process while 84.1% (74/88) respondents were of the opinion that all dying patients would require palliative care. The use of morphine would improve the quality of life of patients according to 68.9% (42/61) of respondents.Conclusion: There are gaps in the knowledge of healthcare workers in the area of palliative care and this call for a review of the current nursing curriculum and practice guidelines in Nigeria.Keywords: End of life, Nursesf attitude, Pain management, Palliative car

Chemical Trends in the Lattice Thermal Conductivity of Li(Ni, Mn, Co)O₂ (NMC) Battery Cathodes

While the transport of ions and electrons in conventional Li-ion battery cathode materials is well understood, our knowledge of the phonon (heat) transport is still in its infancy. We present a first-principles theoretical investigation of the chemical trends in the phonon frequency dispersion, mode lifetimes, and thermal conductivity in the series of layered lithium transition-metal oxides Li(NixMnyCoz)O2 (x + y + z = 1). The oxidation and spin states of the transition metal cations are found to strongly influence the structural dynamics. Calculations of the thermal conductivity show that LiCoO2 has highest average conductivity of 45.9 W·m–1·K–1 at T = 300 K and the largest anisotropy, followed by LiMnO2 with 8.9 W·m–1·K–1 and LiNiO2 with 6.0 W·m–1·K–1. The much lower thermal conductivity of LiMnO2 and LiNiO2 is found to be due to 1–2 orders of magnitude shorter phonon lifetimes. We further model the properties of binary and ternary transition metal combinations to examine the possible effects of mixing on the thermal transport. These results serve as a guide to ongoing work on the design of multicomponent battery electrodes with more effective thermal management

Evolutionary game of coalition building under external pressure

We study the fragmentation-coagulation (or merging and splitting) evolutionary control model as introduced recently by one of the authors, where $N$ small players can form coalitions to resist to the pressure exerted by the principal. It is a Markov chain in continuous time and the players have a common reward to optimize. We study the behavior as $N$ grows and show that the problem converges to a (one player) deterministic optimization problem in continuous time, in the infinite dimensional state space

Polymorph exploration of bismuth stannate using first-principles phonon mode mapping

Accurately modelling polymorphism in crystalline solids remains a key challenge in computational chemistry. In this work, we apply a theoretically-rigorous phonon mode-mapping approach to understand the polymorphism in the ternary metal oxide Bi2Sn2O7. Starting from the high-temperature cubic pyrochlore aristotype, we systematically explore the structural potential-energy surface and recover the two known low-temperature phases alongside three new metastable phases, together with the transition pathways connecting them. This first-principles lattice-dynamics method is completely general and provides a practical means to identify and characterise the stable polymorphs and phase transitions in materials with complex crystal structures

Surface Engineering Strategy Using Urea To Improve the Rate Performance of Na2Ti3O7 in Na‐Ion Batteries

Na2Ti3O7 (NTO) is considered a promising anode material for Na‐ion batteries due to its layered structure with an open framework and low and safe average operating voltage of 0.3 V vs. Na+/Na. However, its poor electronic conductivity needs to be addressed to make this material attractive for practical applications among other anode choices. Here, we report a safe, controllable and affordable method using urea that significantly improves the rate performance of NTO by producing surface defects such as oxygen vacancies and hydroxyl groups, and the secondary phase Na2Ti6O13. The enhanced electrochemical performance agrees with the higher Na+ ion diffusion coefficient, higher charge carrier density and reduced bandgap observed in these samples, without the need of nanosizing and/or complex synthetic strategies. A comprehensive study using a combination of diffraction, microscopic, spectroscopic and electrochemical techniques supported by computational studies based on DFT calculations, was carried out to understand the effects of this treatment on the surface, chemistry and electronic and charge storage properties of NTO. This study underscores the benefits of using urea as a strategy for enhancing the charge storage properties of NTO and thus, unfolding the potential of this material in practical energy storage applications

An evaluation of enteral nutrition practices and nutritional provision in children during the entire length of stay in critical care

<b>Background</b> Provision of optimal nutrition in children in critical care is often challenging. This study evaluated exclusive enteral nutrition (EN) provision practices and explored predictors of energy intake and delay of EN advancement in critically ill children.<p></p> <b>Methods</b> Data on intake and EN practices were collected on a daily basis and compared against predefined targets and dietary reference values in a paediatric intensive care unit. Factors associated with intake and advancement of EN were explored.<p></p> <b>Results</b> Data were collected from 130 patients and 887 nutritional support days (NSDs). Delay to initiate EN was longer in patients from both the General Surgical and congenital heart defect (CHD) Surgical groups [Median (IQR); CHD Surgical group: 20.3 (16.4) vs General Surgical group: 11.4 (53.5) vs Medical group: 6.5 (10.9) hours; p <= 0.001]. Daily fasting time per patient was significantly longer in patients from the General Surgical and CHD Surgical groups than those from the Medical group [% of 24 h, Median (IQR); CHD Surgical group: 24.0 (29.2) vs General Surgical group: 41.7 (66.7) vs Medical group: 9.4 (21.9); p <= 0.001]. A lower proportion of fluids was delivered as EN per patient (45% vs 73%) or per NSD (56% vs 73%) in those from the CHD Surgical group compared with those with medical conditions. Protein and energy requirements were achieved in 38% and 33% of the NSDs. In a substantial proportion of NSDs, minimum micronutrient recommendations were not met particularly in those patients from the CHD Surgical group. A higher delivery of fluid requirements (p < 0.05) and a greater proportion of these delivered as EN (p < 0.001) were associated with median energy intake during stay and delay of EN advancement. Fasting (31%), fluid restriction (39%) for clinical reasons, procedures requiring feed cessation and establishing EN (22%) were the most common reasons why target energy requirements were not met.<p></p> <b>Conclusions</b> Provision of optimal EN support remains challenging and varies during hospitalisation and among patients. Delivery of EN should be prioritized over other "non-nutritional" fluids whenever this is possible.<p></p&gt