Effect of cyclic shearing on contact surfaces of geo-materials under constant normal force

A large amount of research has been done on conforming surfaces in rock joints as well as on the contact between individual grains; however, not much exist in nonconforming contact surfaces subjected to friction, such as flat contacts between ballast particles, stone columns, or riprap; applications that involve the use of coarse gravel subjected to low vertical stresses. Therefore, this article aims to study changes in contact properties between nonconforming flat contacts between large geo-material particles that have been subjected to cyclic shearing under a constant low vertical force, using a direct shear apparatus. Two different silica carbide sandpapers that do not loose particles were used, to simulate different morphologies, a nominally fine and a coarse surface texture. The results show a passivation of the shear strength where a constant value of friction coefficient is reached after around 15 to 17 cycles for all tests, except the tests at the lowest vertical force. For the tests at the highest vertical force, similar friction coefficients were determined for the coarse and fine surfaces. The mass broken during the 10th and 20th cycles was collected at the end of the tests and seemed to show a linear relationship with the vertical force used in the test. Particle analysis, determined via microscopy, shows that the grading is dependent on the initial topography of the surfaces. Despite being subjected to 10 and 20 cycles of shearing, the broken particles look similar in shape with sharp, jagged edges and having different shapes and roundness values with a large variation, indicating that the breakage was not enough to fill in the space between the particles

Aerial Close-Range Photogrammetry to Quantify Deformations of the Pile Retaining Walls

Today, as structures with life expectancy of more than 100 years are being constructed, it is vital to gain knowledge about the gradual decline in material properties. Accordingly, to ensure the longevity and safety of these structures, monitoring has been incorporated as a fundamental part of their service life. To monitor structural deformation, various methods have been developed, with the most common being the survey of certain points of a structure during and after construction using a total station. New techniques are now being developed, and one of the most promising ones is photogrammetry because it provides a simple method to monitor a structure using unmanned air vehicles (UAVs). This paper is aimed at sharing the strategic steps followed in monitoring the deflection of a simple secant pile retaining wall during excavation and construction of a basement. The monitoring is performed using a commercial UAV in combination with point cloud formation, georeferencing, and comparison software (cloud compare, I-Site Studio, 3D Reshaper, etc.). The monitoring results show very good agreement with the traditional inclinometer deflection measurements and numerical analysis, thereby demonstrating the feasibility of the proposed method. The authors believe that in the future, photogrammetry using UAVs can become the standard method for geotechnical monitoring because of its speed, lower cost and ease of use, when compared to conventional methods, a non-destructive method, and is easy to learn and use

Evaluating compliance to Kenya national cancer guidelines on diagnosis and staging of breast cancer at Kenyatta national hospital

Background: In Kenya, breast cancer is one of the most prevalent diseases among women. Early diagnosis and stage-directed treatment are vital in reducing morbidity and mortality associated with it. The Kenya National Cancer Guidelines (KNCG) was developed in 2013. Utility of the guidelines is expected to improve early detection, timely diagnosis, harmonize and standardize treatment of cancer. This study sought to assess whether health care providers at Kenyatta National Hospital are utilizing the guidelines in diagnosis and staging of breast cancer.Study objective: To evaluate adherence to KNCG on diagnosis and staging of breast cancer.Study design: Retrospective descriptive study was conducted within five months. Study subjects: Two hundred and fifty (250) patients’ records with diagnosis of breast cancer between September 2013 and September 2015.Results: Most patients were female 95.6 % with mean age of 47.5±15.5 years. Duration from referral point to index breast clinic review was 10.9±11.1 days. Duration from index breast clinic review to surgery was 64.0 ±114.4 days. Documentation on findings from clinical assessment varied between 24.8 to 86.4%. Documentation on radiological assessment of the breast varied between 3.6 to 35.2% whereas for metastatic assessment varied between 3.6 to 64.0 %. Laboratory investigations documentation varied between 8.4 to 94.8% whereas pathologic diagnosis and tumour biology documentation varied between 3.6-62.4%. American joint cancer committee- tumour, node and metastasis (AJCC-TNM) staging was documented in 16 % of the records reviewed.Conclusion: From this study, triple assessment for breast cancer was incomplete and inconsistent which could result in negatively impacting management of these patients. Every effort should be put in place to track as well as prioritize patients with breast cancer in terms of investigations and surgical interventions in a timely manner. Clinical, radiologic and pathologic assessment must adhere to KNCG and be accurately documented. Clinician should undergo knowledge, attitude and practice (KAP) survey on KNCG so as to identify possible gaps and institute measures aimed at compliance which ultimately could improve care of patients with breast cancer at KNH

Significance of Accounting Information on Equity Share Investment in Nigerian Listed Companies

This study investigated the significance of accounting information on equity share investment in companies listed on Nigerian Stock Exchange. The accounting information variable used to establish the significance of accounting information on equity share investment was net book value per share. The study investigated the influence of net book value per share on equity share investment decision makings in companies listed on Nigeria Stock Exchange. This study used primary data. Data for the study were collected from a sample of 204 respondents from 68 stock brokerage firms in Nigeria. The findings of the study revealed that there is a significant relationship between net book value per share and equity share investment in the listed companies in Nigeria. Specifically, the finding showed that net book value per share has significant influence on equity share investment and was positively correlated with it. This study aimed at providing information that will assist investors in making equity share investment decisions. The findings of this study will assist or guide both potential and existing investors in making investment decisions in listed companies in Nigeria. Keywords:  Accounting information, Equity share investment, Net book value per share,

’The Role of Organisational Climate in Readiness for Change to Lean Six Sigma

Purpose: This study examines the role of organisational climate in readiness for change with particular focus on Lean Six Sigma (LSS). The main aim is to develop and operationalise an instrument to measure organisation climate to determine the organisational readiness of the Kenya Institute of Management (KIM) to progress to the next stage of the Lean Six Sigma (LSS) implementation lifecycle. Design/methodology/approach: A case study outlining the KIM journey to LSS is described. A quantitative survey was developed based on the ten organisation climate dimensions discovered by Ekvall (1983) and redefined by Lauer (1994). This was then used to measure the climate of the case study organisation. Data were analysed to determine individual perceptions of the climate dimensions within KIM. The average score for each dimension was used to determine overall organisational performance and hence readiness for change. Findings: The generally positive scores across each dimension of the survey indicate that the KIM climate is ready for the next stage of its Lean Six Sigma implementation lifecycle although there may be some isolated pockets (individuals or groups) of resistance to change. However, the range of scores on each dimension indicates that there is disagreement within the survey group about the overall organisational climate. Research limitations/implications: The response rate to the climate survey questionnaire was only two-thirds of the total staff at KIM Headquarters and approximately one-fifth of all staff. The views of non-respondents are therefore not known and this may bias the results. Practical implications: Since climate influences readiness for change it is essential that an organisation can measure it to ensure their environment is conducive to the implementation of change generally and Lean Six Sigma particularly. The developed questionnaire is easy to use, easy to analyse and easy to interpret making it an ideal climate measurement instrument. Originality/value: Previous papers on Lean Six Sigma concentrate on organisational culture rather that climate as a success factor for Lean Six Sigma implementation. This paper addresses that omission

Tool for eliminating dog-mediated human rabies through mass dog vaccination campaigns

The World Health Organization and collaborating agencies have set the goal of eliminating dog-mediated human rabies by 2030. Building on experience with rabies endemic countries, we constructed a user-friendly tool to help public health officials plan the resources needed to achieve this goal through mass vaccination of dogs

A heteroskedastic error covariance matrix estimator using a first-order conditional autoregressive Markov simulation for deriving asympotical efficient estimates from ecological sampled Anopheles arabiensis aquatic habitat covariates

<p>Abstract</p> <p>Background</p> <p>Autoregressive regression coefficients for <it>Anopheles arabiensis </it>aquatic habitat models are usually assessed using global error techniques and are reported as error covariance matrices. A global statistic, however, will summarize error estimates from multiple habitat locations. This makes it difficult to identify where there are clusters of <it>An. arabiensis </it>aquatic habitats of acceptable prediction. It is therefore useful to conduct some form of spatial error analysis to detect clusters of <it>An. arabiensis </it>aquatic habitats based on uncertainty residuals from individual sampled habitats. In this research, a method of error estimation for spatial simulation models was demonstrated using autocorrelation indices and eigenfunction spatial filters to distinguish among the effects of parameter uncertainty on a stochastic simulation of ecological sampled <it>Anopheles </it>aquatic habitat covariates. A test for diagnostic checking error residuals in an <it>An. arabiensis </it>aquatic habitat model may enable intervention efforts targeting productive habitats clusters, based on larval/pupal productivity, by using the asymptotic distribution of parameter estimates from a residual autocovariance matrix. The models considered in this research extends a normal regression analysis previously considered in the literature.</p> <p>Methods</p> <p>Field and remote-sampled data were collected during July 2006 to December 2007 in Karima rice-village complex in Mwea, Kenya. SAS 9.1.4^®was used to explore univariate statistics, correlations, distributions, and to generate global autocorrelation statistics from the ecological sampled datasets. A local autocorrelation index was also generated using spatial covariance parameters (i.e., Moran's Indices) in a SAS/GIS^®database. The Moran's statistic was decomposed into orthogonal and uncorrelated synthetic map pattern components using a Poisson model with a gamma-distributed mean (i.e. negative binomial regression). The eigenfunction values from the spatial configuration matrices were then used to define expectations for prior distributions using a Markov chain Monte Carlo (MCMC) algorithm. A set of posterior means were defined in WinBUGS 1.4.3^®. After the model had converged, samples from the conditional distributions were used to summarize the posterior distribution of the parameters. Thereafter, a spatial residual trend analyses was used to evaluate variance uncertainty propagation in the model using an autocovariance error matrix.</p> <p>Results</p> <p>By specifying coefficient estimates in a Bayesian framework, the covariate number of tillers was found to be a significant predictor, positively associated with <it>An. arabiensis </it>aquatic habitats. The spatial filter models accounted for approximately 19% redundant locational information in the ecological sampled <it>An. arabiensis </it>aquatic habitat data. In the residual error estimation model there was significant positive autocorrelation (i.e., clustering of habitats in geographic space) based on log-transformed larval/pupal data and the sampled covariate depth of habitat.</p> <p>Conclusion</p> <p>An autocorrelation error covariance matrix and a spatial filter analyses can prioritize mosquito control strategies by providing a computationally attractive and feasible description of variance uncertainty estimates for correctly identifying clusters of prolific <it>An. arabiensis </it>aquatic habitats based on larval/pupal productivity.</p

Seroprevalence of Brucella spp. and Rift Valley fever virus among slaughterhouse workers in Isiolo County, northern Kenya

Brucella spp. and Rift Valley fever virus (RVFV) are classified as priority zoonotic agents in Kenya, based on their public health and socioeconomic impact on the country. Data on the pathogen-specific and co-exposure levels is scarce due to limited active surveillance. This study investigated seroprevalence and co-exposure of Brucella spp. and RVFV and associated risk factors among slaughterhouse workers in Isiolo County, northern Kenya. A cross-sectional serosurvey was done in all 19 slaughterhouses in Isiolo County, enrolling 378 participants into the study. The overall seroprevalences for Brucella spp. and RVFV were 40.2% (95% CI: 35.2–45.4) and 18.3% (95% CI: 14.5–22.5), respectively while 10.3% (95% CI 7.4%-13.8%) of individuals were positive for antibodies against both Brucella spp. and RVFV. Virus neutralisation tests (VNT) confirmed anti-RVFV antibodies in 85% of ELISA-positive samples. Our seroprevalence results were comparable to community-level seroprevalences previously reported in the area. Since most of the study participants were not from livestock-keeping households, our findings attribute most of the detected infections to occupational exposure. The high exposure levels indicate slaughterhouse workers are the most at-risk population and there is need for infection, prevention, and control programs among this high-risk group. This is the first VNT confirmation of virus-neutralising antibodies among slaughterhouse workers in Isiolo County and corroborates reports of the area being a high-risk RVFV area as occasioned by previously reported outbreaks. This necessitates sensitization campaigns to enhance awareness of the risks involved and appropriate mitigation measures

QTL Mapping of Traits Associated with Dual Resistance to the African Stem Borer (Busseola fusca) and Spotted Stem Borer (Chilo partellus) in Sorghum (Sorghum bicolor)

Sorghum (Sorghum bicolor (L.) Moench) is an important food crop in semi-arid tropics. The crop grain yield ranges from 0.5 t/ha to 0.8 t/ha compared to potential yields of 10 t/ha. The African stem borer Busseola fusca Fuller (Noctuidae) and the spotted stem borer Chilo partellus Swinhoe (Crambidae), are among the most economically important insect pests of sorghum. The two borers can cause 15% - 80% grain yield loss in sorghum. Mapping of QTLs associated with resistance traits to the two stem borers is important towards marker-assisted breeding. The objective of this study was to map QTLs associated with resistance traits to B. fusca and C. partellus in sorghum. 243 F9:10 sorghum RILs derived from ICSV 745 (S) and PB 15520-1 (R) were selected for the study with 4,955 SNP markers. The RILs were evaluated in three sites. Data was collected on leaf feeding, deadheart, exit holes, stem tunnels, leaf toughness, seedling vigour, bloom waxiness, and leaf glossiness. ANOVA for all the traits was done using Genstat statistical software. Insect damage traits and morphological traits were correlated using Pearson’s correlation coefficients. Genetic mapping was done using JoinMap 4 software, while QTL analysis was done using PLABQTL software. A likelihood odds ratio (LOD) score of 3.0 was used to declare linkage. Joint analyses across borer species and sites revealed 4 QTLs controlling deadheart formation; 6 controlling leaf feeding damage; 5 controlling exit holes and stem tunneling damages; 2 controlling bloom waxiness, leaf glossiness, and seedling vigour; 4 conditioning trichome density; and 6 conditioning leaf toughness. Joint analyses for B. fusca and C. partellus further revealed that marker CS132-2 colocalised for leaf toughness and stem tunneling traits on QTLs 1 and 2, respectively; thus, the two traits can be improved using the same linked marker. This study recommended further studies to identify gene(s) underlying the mapped QTLs