355 research outputs found
Socio-Economic and Demographic Classification of HIV/AIDS Patients: Using Cluster Analysis
HIV/AIDS has been spreading in an alarming rate since the beginning of the pandemic. It is estimated that at least half of the affected ones are between 15-24 years. These have called for a concerted effort to save this segment of the population for many reasons. Against this background the study was aimed at classifying socio economic and demographic several of 1500 patients, registered with the university of Maiduguri teaching hospital from 2009 to 2013.Cluster analysis was employed on the set data. The distance which shows similarly between the variable using the coefficient distance was calculated. Dendogram were formed for agglomerative schedule. It was observed that the dendogram formed by the various methods differs according to their coefficient. Even though the single, complete and ward follow similar pattern of cluster except the centriod method, which differ and gave different pattern. Keywords: Agglomerative, Cluster Analysis, Dendogram, and Hierarchica
Influence of Socio-Psychological Factors on Consumer Willingness to Pay (WTP) for Organic Food Products
This study evaluates consumers’ willingness to pay (WTP) a premium for organic vegetables and fruits in Pietermaritzburg metropolis, KwaZulu-Natal province, South Africa, using data collected from 210 consumers approached during their food shopping. The standard economic approach to valuation was extended by including psychological factors. The results from the empirical model show that psychological factors (behavioural control, attitude and subjective norms) exerted more influence on consumers’ WTP for organic products. In addition, socio-demographic factors such as gender, education, number of children in a household, high income and race, are statistically significant in explaining consumers’ WTP for organic food. Policy implications for advancement and improved promotion, sales and consumption of organic food products were discussed.  
Impacts of Rainfall and Forest Cover Change on Runoff in Small Catchments: A Case Study of Mulunguzi and Namadzi Catchment Areas in Southern Malawi
The impacts of climate change on water resources have received much attention globally especially in the last 30 years. Rainfall, the main driver of the hydrological cycle, has been varying in parts of the world in various ways. The picture is more complicated if impacts of land cover changes on water resources are also taken into consideration. These two pose challenges which require an integrated approach to address. Not many of such studies have been conducted in Malawian catchments and other tropical regions. In this study, annual, seasonal and monthly series of rainfall and river discharge of the Mulunguzi and Namadzi River catchments, two small sub-catchments in the Lake Chilwa catchment area, were analysed for trends using the non parametric Mann-Kendall statistic and Sens slope estimator. Further, Linear regression and the RainRU model were applied to establish whether the relationship between rainfall and runoff in the two catchments has changed. Furthermore, linear regression was used to establish how increased forest cover has influenced river flows in the two catchments. The results suggest that rainfall in the Mulunguzi catchment has decreased significantly at all scales and this has also led to reduced river flows. Increased forest cover since the pre 1950s has also resulted in reduced flows but this is not as significant as the rainfall decrease. In the Namadzi catchment, the rainfall trends suggest a varying pattern with no obvious straight trends. At annual and some months timescale, the rainfall has increased significantly. The river flow on the other hand suggests an overall declining pattern. This pattern is well linked with significant forest area increments which have occurred since 1995. It is therefore important that more detailed studies should be conducted to gain further insight to these relations as both catchments are important socioeconomically.Keywords: Land use; land cover; river flow; rainfall; climate change
CONTROL OF PARTICULATE MATTER (PM) EMISSIONS FROM INDUSTRIAL PLANT USING ANFIS BASED CONTROLLER
In recent times, the negative effect of air pollution such as particulate matter (PM) emitted from industrial plants has compelled researchers in finding efficient control system to control such pollutants in order to keep the environment safe. The aim of this study is to develop a reliable method of controlling the emissions of PM using wet scrubber system as a control device. The process of a wet scrubber is nonlinear in nature. Due to difficulty in selecting optimum scrubbing liquid droplet size in wet scrubbing process, the system becomes complex. Thus, Adaptive Neuro Fuzzy Inference System (ANFIS) based control technique is employed in this paper to handle the nonlinearities. ANFIS control technique has the advantage to integrate fuzzy logic systems and learning ability of neural network, thus able to handle nonlinear systems better. The controller is developed using data of PM emission from cement kiln. The system is simulated using triangular and trapezoidal membership function (MF) with 2 and 3 input MF in each case. The performance of the controller is evaluated based on settling time. The results indicated that the developed controller was able to maintain the PM emission below a set point of 20µg/m3 which is the maximum allowable PM emission limit recommended by world health organization (WHO). The controller with 2 input triangular membership functions indicated a better performance with a settling time of 5.2 seconds
Fuzzy logic based intelligent temperature controller for cassava post-harvest storage system
Significant amount of stored agricultural products are lost as a result of poor and inefficient storage systems in most developing countries, especially in tropical regions of the world. Improvements on the existing storage methods is important to guarantee food security. This study proposes the development of intelligent temperature control technique for fresh cassava roots crop post-harvest storage system using fuzzy logic controller (FLC). The intelligent controller which has two inputs (error in temperature and rate of change in the error) and one output (change in fan speed) was simulated with the developed storage system model for temperature control of fresh cassava roots crop. The results obtained shows that the controller can track appropriately the reference temperature and also gives good stability and robustness towards input disturbances. Faster response to maintain the storage temperature within acceptable limit close to reference point was also achieved successfully
Comparing methods of assessing dog rabies vaccination coverage in rural and urban communities in Tanzania
Rabies can be eliminated by achieving comprehensive coverage of 70% of domestic dogs during annual mass vaccination campaigns. Estimates of vaccination coverage are, therefore, required to evaluate and manage mass dog vaccination programs; however, there is no specific guidance for the most accurate and efficient methods for estimating coverage in different settings. Here, we compare post-vaccination transects, school-based surveys, and household surveys across 28 districts in southeast Tanzania and Pemba island covering rural, urban, coastal and inland settings, and a range of different livelihoods and religious backgrounds. These approaches were explored in detail in a single district in northwest Tanzania (Serengeti), where their performance was compared with a complete dog population census that also recorded dog vaccination status. Post-vaccination transects involved counting marked (vaccinated) and unmarked (unvaccinated) dogs immediately after campaigns in 2,155 villages (24,721 dogs counted). School-based surveys were administered to 8,587 primary school pupils each representing a unique household, in 119 randomly selected schools approximately 2 months after campaigns. Household surveys were conducted in 160 randomly selected villages (4,488 households) in July/August 2011. Costs to implement these coverage assessments were 66.12, and $155.70 per village for post-vaccination transects, school-based, and household surveys, respectively. Simulations were performed to assess the effect of sampling on the precision of coverage estimation. The sampling effort required to obtain reasonably precise estimates of coverage from household surveys is generally very high and probably prohibitively expensive for routine monitoring across large areas, particularly in communities with high human to dog ratios. School-based surveys partially overcame sampling constraints, however, were also costly to obtain reasonably precise estimates of coverage. Post-vaccination transects provided precise and timely estimates of community-level coverage that could be used to troubleshoot the performance of campaigns across large areas. However, transects typically overestimated coverage by around 10%, which therefore needs consideration when evaluating the impacts of campaigns. We discuss the advantages and disadvantages of these different methods and make recommendations for how vaccination campaigns can be better monitored and managed at different stages of rabies control and elimination programs
Implementation of Standard Solar PV Projects in Nigeria
The basic operating principle of Photovoltaic device is the conversion of solar irradiation into electricity. There are several applications of this principle. In Nigeria, most solar PV projects are designed for street lighting, water pumping and general stand-alone/minigrid rural electrifications. However, several solar PV projects being installed in various parts of this country fail to meet the minimum life-span due to a number of limiting factors. These include poor or improper fundamental design, use of sub-standard components, adoption of poor installation procedure by inexperienced personnel, bad construction/civil works among other factors. This has become a problem in the country and many are beginning to feel disgusted with solar PV projects as the heavy investments in such projects do not seem to be commensurate with their performances and satisfactions derivable. This paper therefore presents an overview of the performances of solar PV projects and a concise procedural approach to the implementation of standard solar PV projects in the country. In-depth analysis of performances of existing systems was also considered and the limiting factors identified with specific recommendations for improvement. We believe that if power projects are designed and executed properly by experienced technical experts, using the appropriate components and best technical procedures, standard PV projects with maximum performance output could be achieved
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An ERP Investigation on Visuotactile Interactions in Peripersonal and Extrapersonal Space: Evidence for the Spatial Rule
The spatial rule of multisensory integration holds that cross-modal stimuli presented from the same spatial location result in enhanced multisensory integration. The present study investigated whether processing within the somatosensory cortex reflects the strength of cross-modal visuotactile interactions depending on the spatial relationship between visual and tactile stimuli. Visual stimuli were task-irrelevant and were presented simultaneously with touch in peripersonal and extrapersonal space, in the same or opposite hemispace with respect to the tactile stimuli. Participants directed their attention to one of their hands to detect infrequent tactile target stimuli at that hand while ignoring tactile targets at the unattended hand, all tactile nontarget stimuli, and any visual stimuli. Enhancement of ERPs recorded over and close to the somatosensory cortex was present as early as 100 msec after onset of stimuli (i.e., overlapping with the P100 component) when visual stimuli were presented next to the site of tactile stimulation (i.e., perihand space) compared to when these were presented at different locations in peripersonal or extrapersonal space. Therefore, this study provides electrophysiological support for the spatial rule of visual–tactile interaction in human participants. Importantly, these early cross-modal spatial effects occurred regardless of the locus of attention. In addition, and in line with previous research, we found attentional modulations of somatosensory processing only to be present in the time range of the N140 component and for longer latencies with an enhanced negativity for tactile stimuli at attended compared to unattended locations. Taken together, the pattern of the results from this study suggests that visuotactile spatial effects on somatosensory processing occur prior and independent of tactile–spatial attention
Fuzzy Logic Controller (FLC) for the control of Particulate Matter (PM) emission in wet scrubber system
Air pollution such as particulate matter (PM) emitted from industries result in several thousands of deaths. In recognition of this global threat, a large number of abatement measures have been taken to minimize the emission of this pollutant. Wet scrubber system has been the most widely used control device for PM contaminants. Its operating variables (gas velocity, temperature profile, particle size, liquid droplet’s size, terminal settling velocity of liquid droplets, particle density and liquid to gas ratio) fluctuates randomly, thus resulting in a non-linear dynamic behavior of the system. This non-linearity generally limits the ability of the scrubber to control PM less than 5µm in diameter. Thus, in this study, intelligent control technique based on fuzzy logic controller (FLC) has been developed to solve the non-linearity in the system by selecting appropriate scrubbing liquid droplet size in order to improve system performance to control PM that are less than 5µm in diameter. The developed FLC has two inputs (error and change in error) and a single output. The results shows that within short settling time, the controller was able to effectively reduce the PM that are less than 5µm below the set-point (20µg/m3) which is the maximum allowable emission limit of PM contaminants by world health organization (WHO)
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