The origin of the red luminescence in Mg-doped GaN

Optically-detected magnetic resonance (ODMR) and positron annihilation spectroscopy (PAS) experiments have been employed to study magnesium-doped GaN layers grown by metal-organic vapor phase epitaxy. As the Mg doping level is changed, the combined experiments reveal a strong correlation between the vacancy concentrations and the intensity of the red photoluminescence band at 1.8 eV. The analysis provides strong evidence that the emission is due to recombination in which electrons both from effective mass donors and from deeper donors recombine with deep centers, the deep centers being vacancy-related defects.Comment: 4 pages, 3 figure

Modelling of precast concrete composite slab using finite and interface elements

This study presents an efficient finite element analysis technique which shows great versatility in modelling of precast composite flooring system subjected to static loadings. The method incorporates sliding and opening in the analysis of composite structures using the interface element which was specifically designed to simulate the actual behaviour at the interfaces between contacting materials. A three-dimensional finite element model of the precast composite slab which exhibits discontinuous behaviour was performed to demonstrate the potential and applicability of the proposed method of analysis. The results of the analysis demonstrate that the overall response of a discontinuous system to external loading is significantly affected by the bonding condition at the interfaces between the contacting materials

Software development for optimal design of different precast slabs

Precast concrete technology forms an important part in the drive towards a full implementation of the Industrialized Building System (IBS). The IBS requires building components and their dimensions to be standardized, and preferably cast off site. Slabs are major structural elements in buildings, other than beams and columns. Standardized and optimized slabs can significantly enhance the building industries in achieving the full implementation of the IBS. Nevertheless, this requires computer techniques to achieve standardized and optimized slabs which can satisfy all building design requirements, including the standards of architectural and structural design standards. This study proposed a computer technique which analysed and designed five different types of slabs which will satisfy all the requirements in design. The most commonly used slabs included in this study were the solid one way, solid two way, ribbed, voided and composite slabs. The computer techniques enable the design of the most optimized sections for any of the slab types under any loading and span conditions. The computer technique also provides details for the reinforcements required for the slabs

The Design of a Portable Municipal Waste Incinerator with Fuzzy Logic Based Support for Emission Estimation

A fuzzy logic interface system to estimate oxygen requirement for complete combustion as well as the level of pollution from incinerator gas flue in order to manage solid waste from domestic, institutional, medical and industrial sources was designed. The designed incinerator is double chambered operating with a maximum temperature of 760 °C in the lower chamber and 1000°C in the upper chamber. The insulating wall is made up of a refractory brick of 55mm in thickness having a 2mm thickness low carbon steel as the outer wall. Hydrogen Chloride (HCl) and Nitrous oxides (NO)x are the gases was used to demonstrate the Fuzzy Inference System (FIS) model. The FIS was built with five input variables (Food, PVC, Polythene, Paper and Textile) and three input variables with two membership functions. The FIS was developed to estimation the degree of possibility distribution of pollution that should be expected when a certain composition of waste is incinerated. The plots of composition of waste high in food against oxygen require for combustion gives a possibility distribution of about 0.9 which is high according to the fuzzy set definition while the plot of waste composition high in PVC against HCL shows linearity

Partnership for the implementation of mental health policy in Nigeria: a case study of the Comprehensive Community Mental Health Programme in Benue State.

BACKGROUND: 71% of countries in the World Health Organisation's (WHO's) African Region have a stand-alone mental health policy or plan, but only 14% have fully implemented it. In Nigeria, integration of mental health into primary care has been a stumbling block to the implementation of the 1991 National Mental Health Policy, 2013 Policy on Mental Health Services Delivery and the National Mental, Neurological and Substance Use Programme and Action Plan. A partnership between public and private not-for-profits in Benue State, the Comprehensive Community Mental Health Programme (CCMHP) has successfully integrated mental health into primary care in alignment with the national mental health policy and the WHO's mental health Gap Action Programme Intervention Guide (mhGAP-IG). There is a need to document such examples in order to inform policy implementation in Nigeria and other low- and middle-income countries (LMICs). METHODS: We followed the Case Study Methodology to Monitor and Evaluate Community Mental Health Programmes in LMICs. Four field visits were conducted between 2013 and 2017 to document the first phase of activities of CCMHP, covering the period of January 2011 through June 2016. RESULTS: In its first phase, CCMHP trained 19 community psychiatric nurses and 48 community health extension workers in mhGAP-IG, establishing 45 new mental health clinics in primary care facilities across Benue, a state more populous than many countries. As a result, 13,785 clients (55% male, 45% female) were enrolled in mental health services either in primary care or in one of two pre-existing community-based rehabilitation facilities. Most are adults over age 18 (82.75%), and present to services with epilepsy (52.38%) or psychosis (38.41%). CONCLUSION: The case of CCMHP demonstrates it is possible to rapidly scale-up mental health services in line with national mental health policy using the mhGAP-IG, even in a challenging, low-resource setting. Multi-sectoral partnerships may help to overcome some of the barriers to successful integration of mental health into general healthcare by capitalising on the resources and expertise of both state and non-state actors. However, a difficult political context could threaten the sustainability of the programme if funder requirements force a rapid transition to full government ownership

Beehives possess their own distinct microbiomes

Abstract Background Honeybees use plant material to manufacture their own food. These insect pollinators visit flowers repeatedly to collect nectar and pollen, which are shared with other hive bees to produce honey and beebread. While producing these products, beehives accumulate a considerable number of microbes, including bacteria that derive from plants and different parts of the honeybees’ body. Whether bacteria form similar communities amongst beehives, even if located in close proximity, is an ecologically important question that has been addressed in this study. Specific ecological factors such as the surrounding environment and the beekeeping methods used can shape the microbiome of the beehive as a whole, and eventually influence the health of the honeybees and their ecosystem. Results We conducted 16S rRNA meta-taxonomic analysis on honey and beebread samples that were collected from 15 apiaries in the southeast of England to quantify the bacteria associated with different beehives. We observed that honeybee products carry a significant variety of bacterial groups that comprise bee commensals, environmental bacteria and symbionts and pathogens of plants and animals. Remarkably, this bacterial diversity differs not only amongst apiaries, but also between the beehives of the same apiary. In particular, the levels of the bee commensals varied significantly, and their fluctuations correlated with the presence of different environmental bacteria and various apiculture practices. Conclusions Our results show that every hive possesses their own distinct microbiome and that this very defined fingerprint is affected by multiple factors such as the nectar and pollen gathered from local plants, the management of the apiaries and the bacterial communities living around the beehives. Based on our findings, we suggest that the microbiome of beehives could be used as a valuable biosensor informing of the health of the honeybees and their surrounding environment

Service user and caregiver involvement in mental health system strengthening in low- and middle-income countries: a cross-country qualitative study

The aims of this paper are to: (i) explore the experiences of involvement of mental health service users, their caregivers, mental health centre heads and policy makers in mental health system strengthening in three low- and middle-income countries (LMICs) (Ethiopia, Nepal and Nigeria); (ii) analyse the potential benefits and barriers of such involvement; and (iii) identify strategies required to achieve greater service user and caregiver participation. A cross-country qualitative study was conducted, interviewing 83 stakeholders of mental health services. Our analysis showed that service user and caregiver involvement in the health system strengthening process was an alien concept for most participants. They reported very limited access to direct participation. Stigma and poverty were described as the main barriers for involvement. Several strategies were identified by participants to overcome existing hurdles to facilitate service user and caregiver involvement in the mental health system strengthening process, such as support to access treatment, mental health promotion and empowerment of service users. This study suggests that capacity building for service users, and strengthening of user groups would equip them to contribute meaningfully to policy development from informed perspectives. Involvement of service users and their caregivers in mental health decision-making is still in its infancy in LMICs. Effective strategies are required to overcome existing barriers, for example making funding more widely available for Ph.D. studies in participatory research with service users and caregivers to develop, implement and evaluate approaches to involvement that are locally and culturally acceptable in LMICs

Inelastic analysis of composite sections

This paper describes the development of a numerical algorithm used for the inelastic analysis of composite sections subjected to combined axial force and bending moment. The algorithm is based on finding the strain distribution across the section for a given applied loads and mechanical properties of the materials. The application of algorithm is illustrated by analysing a reinforced concrete section. The stress–strain relationship adopted for the concrete is based on a non-linear monotonic model, which is capable of predicting both ascending and descending (softening) parts of the stress–strain curve. For the reinforcing steel, the relation assumed to be bi-linear elasto-plastic in tension and compression. The developed algorithm predicts the exact mode of strain distribution for elastic, plastic and elasto-plastic stages of behaviour. Newton–Raphson concept has been implemented to determine the strain distribution across the section. The algorithm can be used to analyse both regular and irregular cross-section geometry, different materials with single or multi-layered steel bars

Use of mixed methods designs in substance research: a methodological necessity in Nigeria

The utility of mixed methods (qualitative and quantitative) is becoming increasingly accepted in health sciences, but substance studies are yet to substantially benefit from such utilities. While there is a growing number of mixed methods alcohol articles concerning developed countries, developing nations are yet to embrace this method. In the Nigerian context, the importance of mixed methods research is yet to be acknowledged. This article therefore, draws on alcohol studies to argue that mixed methods designs will better equip scholars to understand, explore, describe and explain why alcohol consumption and its related problems are increasing in Nigeria. It argues that as motives for consuming alcohol in contemporary Nigeria are multiple, complex and evolving, mixed method approaches that provide multiple pathways for proffering solutions to problems should be embraced