Socio-ecological systems and biodiversity conservation in African city: Insights from Kano Emir’s Palace gardens

Urban biodiversity management in most African countries is at a peripheral stage. At the same time, African urban areas substantially remain poorly planned and intensively growing. This study explores the socio-ecological system as an alternative approach to explore African indigenous urban biodiversity management. For this purpose, we mixed conventional scientific investigation methods to explain the biodiversity conservation in the ancient gardens of the Kano palace in northern Nigeria. This multidisciplinary approach has successfully unveiled a harmonious relationship of humans and ecosystems in the context of African cultural values and heritage systems. The paper reveals that the palace gardens offer an avenue for intersection of a wide range of ecological and cultural activities. These include biodiversity conservation, recreation, security and surveillance, climate hazards proofing, and sacred dimensions. The findings of this study show that it is possible to address challenges confronting Africa’s urban biodiversity through the combination of scientific and indigenous systems.     

Testing for or against a trend in odds ratios

Consider data arranged into k × 2 × 2 contingency tables. The principal result of this paper is the derivation of the likelihood ratio test and its asymptotic distribution for testing for or against an order restriction placed upon the odds ratios. We will show that the limiting distributions are of chi-bar square type and give the expression of the weighting values.     

On Comparing Cumulative Incidence Functions Using an Empirical Likelihood Ratio Type Test

We consider the competing risks problem with two risks and develop empirical likelihood ratio type tests for testing the null hypothesis that the cumulative incidence functions corresponding to these two risks are equal against the alternatives: (a) they are not equal and (b) they are linearly ordered. The asymptotic null distributions of the proposed test statistics are shown to have simple distribution-free representations in terms of a standard Brownian motion process. The results of a simulation study indicate that the proposed test for testing for the presence of the linear order is more powerful than a test designed for the same situation in Aly et al. (1994 Aly, E.A.A., Kochar, S.C., McKeague, I.W. (1994). Some tests for comparing cumulative incidence functions and cause-specific hazard rates. J. Am. Stat. Assoc. 89:994–999.[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). To illustrate the theoretical results, we discuss an example involving survival times of mice exposed to radiation.     

Final outcome probabilities for SIR epidemic model

Abstract

We consider an SIR stochastic epidemic model in which new infections occur at rate f(x, y), where x and y are, respectively, the number of susceptibles and infectives at the time of infection and f is a positive sequence of real functions. A simple explicit formula for the final size distribution is obtained. Some efficient recursive methods are proved for the exact calculation of this distribution. In addition, we give a Gaussian approximation for the final distribution using a diffusion process approximation.     

Estimation of cumulative incidence functions when the lifetime distributions are uniformly stochastically ordered

In the competing risks problem an important role is played by the cumulative incidence function (CIF), whose value at time t is the probability of failure by time t from a particular type of risk in the presence of other risks. Assume that the lifetime distributions of two populations are uniformly stochastically ordered. Since this ordering may not hold for the empiricals due to sampling variability, it is natural to estimate these distributions under this constraint. This will in turn affect the estimation of the CIFs. This article considers this estimation problem. We do not assume that the risk sets in the two populations are related, give consistent estimators of all the CIFs and study the weak convergence of the resulting processes. We also report the results of a simulation study that show that our restricted estimators outperform the unrestricted ones in terms of mean square error. A real life example is used to illustrate our theoretical results.     

Estimation of extreme quantiles from heavy and light tailed distributions

In Gardes et al. (2011), a new family of distributions is introduced, depending on two parameters τ$\tau$ and θ$\theta$, which encompasses Pareto-type distributions as well as Weibull tail-distributions. Estimators for θ$\theta$ and extreme quantiles are also proposed, but they both depend on the unknown parameter τ$\tau$, making them useless in practical situations. In this paper, we propose an estimator of τ$\tau$ which is independent of θ$\theta$. Plugging our estimator of τ$\tau$ in the two previous ones allows us to estimate extreme quantiles from Pareto-type and Weibull tail-distributions in an unified way. The asymptotic distributions of our three new estimators are established and their efficiency is illustrated on a small simulation study and on a real data set.     

An application of negative binomial distribution of order k in sensitive surveys

This article is an attempt to generalize some of the recent papers on randomized response techniques by using the negative binomial distribution of order k to randomize the responses in the randomization design where respondents can report outcome of one of two binary devices depending upon their actual status. The relative efficiency results are observed to be better than those of many recent and relevant randomized response techniques. The results are also better than those of the base line model used in this study, providing the sensitive attribute is rare. An extra advantage of the proposed technique is that it does not require any additional sampling and administrative cost.     

Green and lean: a Gemba–Kaizen model for sustainability enhancement

Abstract

Despite the encouraging results obtained from the application of Green Lean, organizations have found the integration of Green and Lean, and their implementation as an integrated approach, challenging. This paper therefore presents a model for integrating Lean and Green based on the Gemba-Kaizen approach. The proposed model was developed on the basis of a through literature review on Gemba and Kaizen, conducted on peer reviewed journal articles and pragmatic books, and the more than 40 years of accumulated experience of the authors as academics, researchers, industrialists and consultants. The model was validated through two cases study in the aerospace and automotive industries. The results showed that the proposed model helped the case organizations to reduce the consumption of resources and improve their environmental performance. The proposed model can be the basis for further research on Lean and Green, contributing to help organizations to improve their sustainability performance.